JP4630619B2 - Development device - Google Patents

Description

  The present invention relates to a developing device that performs development using a developer, and more particularly to a developing device used in an image forming apparatus such as a copying machine or a printer using an electrophotographic recording system.

Conventionally, as a developing device applied to an image forming apparatus using a magnetic developer, there is one in which a hopper chamber and a developing chamber are arranged (see, for example, Patent Document 1 and Patent Document 2).
A conventional example will be described with reference to FIG. FIG. 3 is a schematic cross-sectional view of a batch supply type developing device.

  The developer carrying member 101 rotates in the direction of the arrow, and a developer layer is formed on the surface of the developer carrying member 111 by the developer regulating member 111. The developer is conveyed and developed at a position facing the image carrying member 102. ing. A developing chamber 103 is disposed adjacent to the developer carrying member 101, and the developer is stirred by a developing chamber stirring member 104 that conveys the developer to the developer carrying member 101 while stirring the developer along the longitudinal direction of the developer carrying member 101. A developer is supplied to the carrier 101. A hopper chamber 105 is adjacent to the developing chamber 103 through a partition wall 109. The hopper chamber 105 is provided with a rotating stirring member 106 that conveys the developer toward the developing chamber 103 while stirring the developer, and the supply amount is adjusted by the opening 110. In addition, an opening 112 that can be opened and closed for replenishing the developer is provided in the upper part of the developing device.

  The developing chamber agitating member 104 and the rotating agitating member 106 rotate at a constant ratio with respect to the rotational speed of the developer carrier 101 to agitate and convey the developer.

  When the developer is replenished, the replenished developer is agitated by the rotary agitating member 106 and simultaneously conveyed toward the developing chamber 103 through the opening 110.

  Further, as a method for optimizing the amount of magnetic developer supplied to the developer carrier, there is a method in which a developer carrier is disposed in the upper opening of the developing device (see, for example, Patent Document 3). Briefly described with reference to FIG. 9, a developer regulating member 111 that is disposed opposite to the developer carrier 101 and regulates the amount of developer on the developer carrier 101 and has magnetism, and after passing through the development region. A separation member that peels off the developer on the developer carrier 101, a partition member that partitions the development chamber 103 including the developer regulating member 111 and the second region including the separation member, and a development chamber On the partition member, a staying member that temporarily retains the developer conveyed from the rotary stirring member 106 in front of the developer carrying member 101 is erected with the upper space remaining, and the staying member and the developer carrying member are left standing. 101 is formed as a developer non-retention area.

  In addition, there is a roller in which a developer is supplied to the developer carrier below the developer carrier (see, for example, Patent Document 4).

  Further, the developer is made spherical in order to optimize the charge amount of the developer and improve the fluidity, for example, the circularity of the magnetic developer, the weight average particle diameter (d50) of the toner, and the surface roughness of the developer carrier. There is one that defines a ratio d50 / Ra to the thickness (Ra) (see, for example, Patent Document 5) and one that defines a cumulative value of a developer having a certain circularity or more (see, for example, Patent Document 6).

  As a method for preventing sleeve contamination / fusion, there is an Rz / Ra method that defines the value of the average inclination Δa of the developer carrier (see, for example, Patent Document 7).

  In addition, there is one that defines the Rp / Rv ratio and Rz / Rv ratio of a developer carrier (see, for example, Patent Document 8).

JP 2001-147777 A JP 2002-196574 A Japanese Patent Laid-Open No. 11-044991 JP 2004-004380 A JP 2000-003072 A JP 2002-311636 A JP 2000-089572 A JP 2003-202749 A

  However, in the conventional example shown in FIG. 3, the developer accumulated on the back side of the developer regulating member 111 is scraped by the developing chamber stirring member 104, but the developer accumulates in a portion where the developing chamber stirring member 104 does not reach. In this case, the developer packing occurs in this portion, and problems such as deterioration of the developer, poor coating of the developer on the developer carrying member, and resulting low development density occur. Further, since the developer is supplied to the developer carrier 101, the developing chamber 103 is also provided in addition to the hopper chamber 105. Therefore, it is difficult to save the space of the developing device, and the image forming apparatus cannot be made compact. Furthermore, since the developing chamber stirring member 104 must be provided in addition to the rotating stirring member 106, the cost increases.

  In the conventional example shown in FIG. 9, since the developing chamber 103 is also arranged in addition to the hopper chamber 105, and further, the partition member and the peeling member are also installed, it is difficult to save space and reduce costs.

  In Patent Document 4, a non-magnetic developer is conveyed to a developer carrying member by a brush supply roller. However, a magnetic developer having a large specific gravity may not be suitably conveyed and supplied.

  On the other hand, in response to the demand for higher image quality and reduction in power consumption of copying machines in recent years, as the particle size and the softening point of the magnetic developer are reduced, the developer can be used over a long period of time. There is a stronger tendency of fusing to the irregularities on the surface of the carrier and leading to contamination.

  When the developer fusing occurs on the surface of the developer carrying member, first, the transport amount of the developer to the developing area is lowered, and the image density is likely to be lowered. Conventionally, in order to perform good development, a developing bias is applied to the developer carrying member at the time of development. However, if toner fusion occurs on the surface of the developer carrying member, the fused product is applied to the surface of the developer carrying member. A high resistance layer is formed by the above, and a desired electric field is not formed in the development region between the developer carrier and the image carrier at the time of development. The density tends to decrease and image defects such as white spots are likely to occur.

  In the case of Patent Document 7, which defines the value of the average inclination Δa of the developer carrying member in order to improve the above-mentioned contamination / fusion, Δa is a parameter relating to the roughness inclination, and refers to the height of the peak. Therefore, a sufficient effect was not seen in the developing device in which the fluidity of the developer deteriorates. In the case of Patent Document 8, etc. that define the Rp / Rv ratio and the Rz / Rv ratio, it relates to a developing device using a two-component developer, so that a sufficient effect can be obtained in the case of a developing device using a magnetic one-component developer. I couldn't.

  By the way, in the case of reducing the space and cost of the developing device, since the installation of the stirring member and the developing chamber becomes the minimum necessary, the fluidity in the developing device tends to deteriorate. Therefore, there is a method of improving the fluidity by spheroidizing the developer and supplying a stable quantity. However, in Patent Document 5, the developer transport amount is optimized based on the spheroidizing developer and the d50 / Ra parameter. However, in the developing device of the present invention, sleeve contamination and fusion occur. In Patent Document 6, sleeve contamination and fusion cannot be prevented only by the material configuration of the conductive resin coating layer.

  The object of the first invention according to the present application is to provide a one-component magnetic developer, even when the developing device is simplified and made compact in order to realize cost reduction and space saving of the image forming device. It is an object of the present invention to provide a developing device that realizes an image forming apparatus excellent in durability of a large number of sheets under normal temperature and normal humidity, normal temperature and low humidity, or high temperature and high humidity.

  In addition, there is no sleeve contamination or fusion even in long-term durability, and high-quality images that do not cause image quality degradation such as image density reduction, ghost, blotch, and solid white fog as well as room temperature and normal humidity as well as room temperature and low humidity It is to be.

An object of the second invention according to the present application is to provide a developing device that supplies a toner having an appropriate charge amount onto a developer carrier and realizes a stable image forming apparatus.
An object of the third invention according to the present application is to provide a developing device in which solid black density unevenness does not occur even in long-term durability.

In order to achieve the above object, the first invention according to the present application,
Magnetic developer,
A developer container having the magnetic developer therein;
A developer carrier that is disposed in the upper opening of the developer container and that is disposed in proximity to or in pressure contact with the image carrier to supply the magnetic developer;
Rotating agitation means for moving the magnetic developer inside the developer container toward the developer carrier;
Replenishment detection means for detecting replenishment of the magnetic developer inside the developer container,
The lower end of the developer carrying member in the developing apparatus is positioned at the top than the central axis of rotation of the rotary stirring means,
The magnetic developer includes magnetic developer particles obtained by pulverizing a solidified product of a melt-kneaded material including a binder resin, a magnetic material, and a release agent by mechanical pulverization and an external additive, and includes a weight average particle. In particles having a diameter of 5 μm to 12 μm and 3 μm or more of the magnetic developer, 90% or more of particles having a circularity a calculated from the following formula (1) of 0.900 or more in terms of the number-based cumulative value. ,
Circularity a = L ₀ / L ------- (1)
[Expression, L ₀ represents the circumference of a circle having the same projected area as the particle image, and L represents the circumference of the particle image. ]

The developer carrying member has a resin coating layer on the surface of at least the substrate and the substrate,
The oil sump depth of the surface of the resin coating layer (Rvk) is 2.0μm or less, and the initial wear height (Rpk) is characterized in that it is a current image device Ru der below 3.0 [mu] m.

  Further, a second invention according to the present application is characterized in that the upper end of the replenishment detecting means is a developing device positioned below the rotating shaft of the stirring means.

  Furthermore, a third invention according to the present application is a developing device in which a powder surface of the magnetic developer in the developer container is below a lower end of the developer carrier.

  According to the present invention, according to the first aspect of the present application, an appropriate amount of developer can be supplied to the developer carrying member without providing a plurality of stirring members in the developing device. In addition, since the toner stirring chamber and the developing chamber can be integrated, the developing device can be simplified and made compact, and at the same time, a developing device free from sleeve contamination and fusion can be provided even in long-term durability. In addition, it is possible to provide a developing device that realizes an image forming apparatus excellent in durability of a large number of sheets under normal temperature and normal humidity, normal temperature and low humidity, and high temperature and high humidity in a one-component magnetic developer. In addition to room temperature and normal humidity, high-quality images can be obtained over a long period of time without causing image quality defects such as image density reduction, ghost, blotch, and fog at room temperature, low humidity, and high temperature and high humidity. That is, a stable high-quality image can be provided.

  Further, according to the second invention of the present application, since the powder surface of the developer is always located below the rotating shaft of the stirring means, the toner can be well stirred. As a result, in terms of durability, it is possible to supply a toner having an appropriate charge amount onto the developer carrying member, and to provide a developing device that realizes a stable image forming apparatus.

  Further, according to the third invention of the present application, the toner fluidity does not fluctuate, the toner coat unevenness on the developer carrier is eliminated, and as a result, the solid black density unevenness does not occur even in the latter half of the durability. Can be provided.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the following embodiments should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions. As long as there is no specific description, it is not the meaning which limits the scope of the present invention only to them.

  First, a developing device to which the present invention is applied will be described in detail with reference to FIG. FIG. 1 shows an example of a sectional view of the developing device of the present invention.

  As shown in FIG. 1, the developer carrier 1 is rotated in the direction of the arrow, and a developer layer is formed on the surface of the developer regulating member 11 to convey the developer. Development is performed at the opposite position.

  A hopper chamber 5 is adjacent to the developer carrier 1. The hopper chamber 5 is provided with a rotating stirring member 6 that transports the developer toward the developer carrier 1 while stirring the developer, and supplies the developer to the developer carrier 1. In addition, an opening 12 that can be opened and closed for supplying a developer is provided in the upper part of the developing device.

  In the hopper chamber 5, a developer replenishment detecting member 13 is arranged so that the position about 15 mm from the bottom of the developing container, on the other side of the hopper chamber wall, is the center.

  The developer replenishment detection member 13 is composed of a piezoelectric element, which detects the presence or absence of the developer in a portion immediately inside the developer replenishment detection member 13 in the hopper chamber 5 and develops the detection signal. This is communicated to the agent supply determination device 14. The developer replenishment determination device 14 continuously receives a signal from the developer replenishment detection member 13, and determines that there is no developer when it receives a no-developer signal from the developer replenishment detection member 13. The sensor surface of the developer replenishment detection member 13 has a circular shape with a diameter of 10 mm, and the developer is present in all regions on the sensor surface since no developer is present in the region of 1/2 or more on the sensor surface. A signal indicating that there is no developer is output in one of the states before the start. That is, the output of the signal indicating no developer is started while the developer is reduced to the line a in FIG. 1 while the developer is reduced to the line b.

  In the developing device of the present embodiment, the target remaining developer amount when determining the absence of developer is 200 g.

  In the present embodiment, the height d of the lower end of the developer carrier 1 is about 50 mm from the bottom of the developing container. The height g of the rotation center axis of the rotary stirring member 6 is about 40 mm from the bottom of the developing container. The height t of the powder surface of the developer in the hopper chamber 5 is at a position of about 45 mm from the bottom of the developing container at the maximum. The height s of the upper end of the developer supply detection member 13 is about 20 mm from the bottom of the developing container. Therefore, the height t of the powder surface of the developer is between about 20 to 45 mm from the bottom of the developing container.

  The present invention is not limited to the above numerical values. For example, the lower end of the developer carrier 1 may be at a position higher than the rotation center axis of the rotary stirring member 6, and the upper end of the developer supply detection member 13 is higher than the rotation center axis of the rotation stirring member 6. Any lower position is acceptable. Furthermore, the powder surface of the developer in the hopper chamber 5 may be at a position lower than the lower end of the developer carrier 1.

  The developer replenished from the opening 12 at the top of the developing container enters the hopper chamber 5, and the developer is conveyed to the developer carrying member 1 by the rotary stirring member 6. At this time, since the rotation center shaft height g of the rotary stirring member 6 is located below the lower end of the developer carrier 1, the developer supply to the developer carrier 1 is pumped up from below. It is not over-supplemented, but is supplied in appropriate amounts. Therefore, as in the conventional developing device as shown in FIG. 5, in order to optimize the developer supply amount, an extra space is provided in which a developing chamber 103 is provided in addition to the hopper chamber 105 and the supply amount is adjusted by the opening 110. There is no need to provide.

  Further, as shown in FIG. 1, the developer on the back side of the developer regulating member 11 in the present embodiment moves upward along the developer regulating member and eventually falls below the hopper chamber 5 due to the influence of gravity. Good prevention of developer packing can be achieved. Therefore, unlike the conventional developing device, it is not necessary to install the developing chamber stirring member 104 and scrape off the developer staying behind the developer regulating member 11. At this time, the angle θb formed with the horizontal direction of the developer regulating member 11 in the developing device is preferably 45 ° or less in order to prevent good packing. When the angle exceeds 45 °, the developer on the back side of the developer regulating member 11 is hardly affected by gravity and does not fall below the hopper chamber 5 but stays in the vicinity of the developer carrying member on the back side of the developer regulating member 11 and eventually develops. Excessive agent is generated and strong packing is generated, and the magnetic developer is likely to be deteriorated, faded, and thin at the end.

  In the present embodiment, a ferromagnetic metal material is used as the developer regulating member 11, but a non-magnetic material can also be used.

  On the other hand, it has been conventionally known that the shape of the magnetic developer affects various properties of the magnetic developer, but the present inventors have examined the particle size and shape of the magnetic developer produced by the pulverization method. As a result, it was found that the degree of circularity, transferability, developability (image quality), and fixability of particles of 3 μm or more are closely related.

  Further, in order to exert the same effect in magnetic developers having different particle diameters, it is necessary to control the circularity of particles having a particle size of 3 μm or more by the magnetic developer weight average diameter and the fine powder content of less than 3 μm.

  That is, by defining the circularity of particles having a particle size of 3 μm or more by the magnetic developer weight average diameter and the fine powder content of less than 3 μm, a magnetic developer having excellent transferability, developability (image quality) and fixability can be obtained. I can do it.

  By reducing the particle size of the magnetic developer, the specific surface area of the magnetic developer particles increases. This increases the cohesiveness and adhesion of the magnetic developer. For this reason, when the magnetic developer image is transferred onto the transfer material from the photosensitive member, the adhesion force acting between the photosensitive member and the magnetic developer becomes strong, and the transfer efficiency is lowered. In particular, the magnetic developer produced by the conventional pulverization method becomes irregular and angular, and this tendency becomes remarkable.

  That is, even if the particle size is small, the transfer efficiency is improved by having a low adhesion equivalent to or higher than that of the normal particle size magnetic developer.

  When the magnetic developer has a relatively large particle size, the specific surface area of the magnetic developer particles becomes small. For this reason, the adhesive force acting between the photoreceptor and the magnetic developer is weaker than that of the magnetic developer having a reduced particle size. In other words, when a magnetic developer having a large particle size has a circularity distribution equivalent to that of a small particle size magnetic developer, the effect of reducing adhesion is further increased and transfer efficiency is improved. And other problems such as image quality degradation.

  Furthermore, when a magnetic developer with a reduced particle size is used, dot reproducibility is good, but fog and scattering tend to deteriorate. This is because, in order to produce a magnetic developer of fine particles from a coarsely pulverized magnetic developer, a magnetic developer such as fine powder and ultrafine powder and a large number of particles having a target particle size are mixed. Conceivable. That is, magnetic developers having different particle diameters have different charging characteristics and different adhesion properties with individual particles. For this reason, by reducing the particle size, the charge amount distribution of the magnetic developer becomes conversely wide. In order to control these, it is important to control the circularity distribution of the magnetic developer particles having a particle size of 3 μm or more depending on the amount of the magnetic developer particles having a particle size of less than 3 μm or ultrafine powder.

  Although it is possible to obtain a sharp particle size distribution by repeatedly classifying the pulverized magnetic developer, it is difficult to adapt to actual magnetic developer production.

  In other words, according to the study by the present inventors, in the magnetic developer produced by the pulverization method, the waste magnetic development is improved by improving the transfer rate when transferring the magnetic developer image onto the transfer material from the photoreceptor. It has been found that it is important for the magnetic developer to have a specific particle size distribution and circularity in order to suppress the generation of the agent and achieve good low-temperature fixability and high developability.

  In the magnetic developer having a specific circularity of the present invention, the weight average diameter is preferably 5 to 12 μm, more preferably 5 to 10 μm.

  When a magnetic developer having a weight average particle diameter exceeding 12 μm is reduced in dot reproducibility and a magnetic developer having a weight average diameter exceeding 12 μm is obtained, the load in the pulverizer is reduced as much as possible, or the processing amount is reduced. Increasing the particle size can cope with the particle size, but the shape becomes angular, making it difficult to achieve a desired circularity, and it is difficult to achieve a desired circularity distribution.

  The magnetic developer having a weight average particle size of less than 5 μm particularly deteriorates the fog in the image quality, and when obtaining a magnetic developer having a weight average particle size of less than 5 μm, the load in the pulverizer is increased or the processing amount is increased. However, it is difficult to achieve a desired circularity by approximating the shape to a sphere, and it is difficult to obtain a desired circularity distribution. It becomes impossible to suppress the occurrence of.

  Further, in the particles of 3 μm or more of the magnetic developer in the present invention, 90% or more of particles having a circularity a of 0.900 or more in terms of the number-based cumulative value can easily control the charging of the magnetic developer, It is preferable at the point which can obtain equalization and durability stability. It is also preferable that the transfer efficiency is increased. This is because, in the case of a magnetic developer having a circularity as described above, the contact area between the magnetic developer particles and the photoconductor is reduced, so that the adhesion force acting between the magnetic developer and the photoconductor is reduced. It is.

  When the presence of particles having a circularity a of 0.900 or more in particles of 3 μm or more of the magnetic developer in the present invention is less than 90% in terms of the number-based cumulative value, the contact between the magnetic developer particles and the photosensitive member Since the area increases and the adhesion force of the magnetic developer particles to the photoreceptor increases, it is not preferable because sufficient transfer efficiency cannot be obtained.

  Further, the number of particles having a particle size of less than 4.00 μm in the present invention is 40% by number or less, preferably 5 to 35% by number, and particles having a particle size of 10.08 μm or more are preferably 0 to 20% by volume, 25 A toner having a particle size distribution of not more than volume% is preferable.

  When the number of particles less than 4.00 μm exceeds 40% by number, it is difficult to obtain a desired circularity and circularity distribution for the same reason as that for obtaining a magnetic developer having a weight average diameter of less than 5 μm. When the particle size of 10.08 μm or more exceeds 25% by volume, it is difficult to obtain a desired circularity and circularity distribution for the same reason as in the case of obtaining a magnetic developer having a weight average diameter exceeding 12 μm.

Further, in the present invention, the abundance of fine particles of 3 μm or less is obtained by subtracting the ratio of the particle concentration of the particle group having a circle equivalent diameter of 3 μm or more from the particle concentration of all the measured particles from 100% (hereinafter, cut) When expressed, the relationship between the cut rate Z and the magnetic developer weight average diameter X satisfies the following formula (2):
Cut rate Z ≦ 5.3 × X (2)
[However, the cut rate Z is the particle concentration A (number / μl) of all measured particles measured with a flow type particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics, and the measured particle concentration B (number of particles with an equivalent circle diameter of 3 μm or more) / Μl), it is shown by the following formula (3).
Z = (1-B / A) × 100 (3)]

The relationship between the number-based cumulative value Y of particles having a circularity of 0.950 or more and the magnetic developer weight average diameter X preferably satisfies the following formula (4).
Number reference value Y ≧ exp5.51 × X ^−0.645 of particles having a circularity of 0.950 or more (4)
[However, weight average particle diameter X of magnetic developer: 5 to 12 μm]

  When it has such a circularity, the charge control of the magnetic developer is easy, and uniform charge and durability stability can be obtained. Further, it has been found that the transfer efficiency is increased when the circularity is as described above. This is because, in the case of a magnetic developer having a circularity as described above, the contact area between the magnetic developer particles and the photoconductor is reduced, so that the adhesion force acting between the magnetic developer and the photoconductor is reduced. It is. Furthermore, since the specific surface area of the magnetic developer particles is reduced as compared with the magnetic developer produced by the conventional collision type airflow crusher, the contact area between the magnetic developer particles is reduced, and the magnetic developer is reduced. The bulk density becomes dense, and the effect of improving the fixing property can be obtained by improving the heat conduction during fixing.

The particles having a circularity a of 0.950 or more in the particles of 3 μm or more of the magnetic developer are cumulative values based on the number, and the relationship between the cut rate Z and the magnetic developer weight average diameter X is expressed by the following formula: Cut rate Z ≦ 5. 3 × X (preferably 0 <cut rate Z ≦ 5.3 × X)
And the number reference cumulative value Y ≧ exp5.51 × X ^−0.645 is not satisfied, that is, the number reference cumulative value Y <exp5.51 × X ^−0.645 is satisfied, Adhesion is facilitated and sufficient transfer efficiency cannot be obtained, and the fluidity of the magnetic developer may be deteriorated, which is not preferable.

In the case of the cutting rate Z> 5.3 × X, it indicates that the number of particles of 3 μm or less is large, and even when the number reference cumulative value Y ≧ exp5.51 × X ^−0.645 is satisfied, it is circular due to the presence of fine particles. This is unsatisfactory because it is insufficient in some cases and sufficient transfer efficiency may not be obtained.

  The circularity standard deviation SD can also be used as one standard for the variation of particles having such circularity. In the present invention, the circularity standard deviation SD is preferably 0.030 to 0.045.

  In the magnetic developer of the present invention, the particle size distribution of the magnetic developer is measured using a 100 μm aperture in a Coulter Counter TA-II type or Coulter Multisizer II type manufactured by Coulter, which will be described later. The average circularity is used as a simple method for quantitatively expressing the shape of the particles. In the present invention, the flow type particle image analyzer “FPIA-1000” manufactured by Toa Medical Electronics is used for measurement, The circularity of the measured particles is obtained by the following formula (1), and the value obtained by dividing the total roundness of all particles measured by the total number of particles as defined by the following formula (5) is defined as the average circularity. To do.

Circularity a = L ₀ / L (1)
[In the formula, L ₀ represents the circumference of a circle having the same projected area as the particle image, and L represents the circumference of the particle image. ]

  The circularity in the present invention is an index of the degree of unevenness of the magnetic developer particles, and indicates 1.00 when the magnetic developer is a perfect sphere. The more complex the surface shape, the smaller the circularity. The SD of the circularity distribution in the present invention is an indicator of variation, and the smaller the value, the sharper the distribution.

  “FPIA-1000”, which is a measuring apparatus used in the present invention, calculates the circularity of each particle, and then calculates the average circularity and the circularity standard deviation. .4 to 1.0 are divided into 61 classes, and a calculation method is used in which the average circularity and the circularity standard deviation are calculated using the center value and frequency of the division points. However, each value of the average circularity and the circularity standard deviation calculated by this calculation method, and each value of the average circularity and the circularity standard deviation calculated by the calculation formula that directly uses the circularity of each particle described above, In the present invention, the error of each particle described above is reduced for the reason of handling data such as shortening the calculation time and simplifying the calculation formula. Such a calculation method that is partially changed by using the concept of a calculation formula that directly uses the circularity may be used.

  As a specific measuring method, 0.1 to 0.5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersing agent to 100 to 150 ml of water in which impurities have been removed in advance, and a measurement sample is 0. Add about 1-0.5g. The suspension in which the sample is dispersed is subjected to dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, the dispersion concentration is set to 1 to 220,000 pieces / μl, and the flow type particle image measuring apparatus is used. The circularity distribution of particles having an equivalent circle diameter of 0.60 μm or more and less than 159.21 μm is measured. In addition, by setting the dispersion concentration to 1.2 to 2 million pieces / μl, it is possible to maintain a particle concentration that can maintain the accuracy of the apparatus even when the cutting rate increases.

  The outline of the measurement is described in the catalog (June 1995 edition) of FPIA-1000 published by Toa Medical Electronics Co., Ltd., the operation manual of the measuring apparatus, and JP-A-8-136439. It is.

  The sample dispersion is passed through a flat and flat transparent flow cell (thickness: about 200 μm) flow path (spread along the flow direction). The strobe and the CCD camera are mounted on the flow cell so as to be opposite to each other so as to form an optical path that passes through the thickness of the flow cell. While the sample dispersion is flowing, strobe light is irradiated at 1/30 second intervals to obtain an image of the particles flowing through the flow cell, so that each particle has a certain range parallel to the flow cell. Photographed as a two-dimensional image. From the area of the two-dimensional image of each particle, the diameter of a circle having the same area is calculated as the equivalent circle diameter. The circularity of each particle is calculated from the projected area of the two-dimensional image of each particle and the perimeter of the projected image using the above circularity calculation formula.

  In order to produce a magnetic developer having the above circularity and particle size distribution, it is preferable to use a mechanical pulverizer described below. Hereinafter, the mechanical pulverizer shown in FIGS. 16, 17 and 18 will be described. 16 shows a schematic cross-sectional view of an example of a mechanical pulverizer used in the present invention, FIG. 17 shows a schematic cross-sectional view along the line DD ′ in FIG. 16, and FIG. FIG. 17 shows a perspective view of the rotor 314 shown in FIG. 16. As shown in FIG. 16, the apparatus has a large number of grooves on a surface that rotates in a casing 313, a jacket 316, a distributor 220, and a rotating body that is attached to a central rotating shaft 312 in the casing 313. The provided rotor 314, the stator 310 provided with a large number of grooves on the outer periphery of the rotor 314, which are arranged at regular intervals, and the raw material input for introducing the raw material to be treated The port 311 includes a raw material discharge port 302 for discharging the processed powder.

  The pulverization operation in the mechanical pulverizer configured as described above is performed, for example, as follows.

  That is, when a predetermined amount of powder raw material is introduced from the powder inlet 311 of the mechanical pulverizer shown in FIG. 16, the particles are introduced into the pulverization chamber and are rotated on the surface rotating at high speed in the pulverization chamber. The impact generated between the rotor 314 provided with a large number of grooves and the stator 310 provided with a large number of grooves on the surface, a large number of ultrahigh-speed vortices generated behind this, and the generated It is crushed instantaneously by high-frequency pressure vibration. Thereafter, the material passes through the material discharge port 302 and is discharged. The air carrying the toner particles passes through the pulverization chamber and is discharged out of the apparatus system through the material discharge port 302, the pipe 219, the collecting cyclone 229, the bag filter 222, and the suction filter 224. Is done. In the present invention, since the powder raw material is pulverized in this manner, a desired pulverization treatment can be easily performed without increasing the fine powder and coarse powder.

  When the pulverized raw material is pulverized by a mechanical pulverizer, it is preferable that cold air is blown into the mechanical pulverizer together with the powder raw material by the cold air generating means 321. Furthermore, the temperature of the cold air is preferably 0 to -18 ° C. Further, as an in-machine cooling means of the mechanical pulverizer body, the mechanical pulverizer preferably has a structure having a jacket structure 316, and it is preferable to pass cooling water (preferably an antifreeze such as ethylene glycol). Furthermore, due to the cold air device and the jacket structure described above, the room temperature T1 in the spiral chamber 212 communicating with the powder inlet in the mechanical pulverizer is 0 ° C. or less, more preferably −5 to −15 ° C., still more preferably −7. It is preferable to set the temperature to -12 ° C from the viewpoint of toner productivity. By setting the room temperature T1 of the swirl chamber in the pulverizer to 0 ° C. or less, more preferably −5 to −15 ° C., and still more preferably −7 to −12 ° C., surface modification of the toner due to heat can be suppressed, and efficiency The pulverized raw material can be pulverized well. When the room temperature T1 of the swirl chamber in the pulverizer exceeds 0 ° C., it is not preferable from the viewpoint of toner productivity because the surface of the toner is easily deteriorated or fused in the machine during pulverization. If the room temperature T1 of the spiral chamber in the pulverizer is to be operated at a temperature lower than −15 ° C., the refrigerant (alternative chlorofluorocarbon) used in the cold air generating means 321 must be changed to chlorofluorocarbon.

  Currently, chlorofluorocarbons are being eliminated from the viewpoint of protecting the ozone layer. Use of chlorofluorocarbon as the refrigerant of the cold air generating means 321 is not preferable from the viewpoint of global environmental problems.

  Alternative CFCs include R134A, R404A, R407C, R410A, R507A, R717, etc. Among them, R404A is particularly preferable from the viewpoint of energy saving and safety.

  Cooling water (preferably antifreeze such as ethylene glycol) is supplied into the jacket from the cooling water supply port 317 and discharged from the cooling water discharge port 318.

  The finely pulverized product generated in the mechanical pulverizer is discharged from the powder discharge port 302 to the outside through the rear chamber 320 of the mechanical pulverizer. At this time, the room temperature T2 of the rear chamber 320 of the mechanical pulverizer is preferably 30 to 60 ° C. from the viewpoint of toner productivity. By setting the room temperature T2 of the rear chamber 320 of the mechanical pulverizer to 30 to 60 ° C., it is possible to suppress the toner surface deterioration due to heat and to efficiently pulverize the pulverized raw material. When the temperature T2 of the mechanical pulverizer is lower than 30 ° C., there is a possibility of causing a short pass without being pulverized, which is not preferable from the viewpoint of toner performance. On the other hand, when the temperature is higher than 60 ° C., it may be excessively pulverized at the time of pulverization, and it is not preferable from the viewpoint of toner productivity because the surface of the toner is easily deteriorated or melted in the machine.

When the pulverized raw material is pulverized by a mechanical pulverizer, the temperature difference ΔT (T2−T1) between the room temperature T1 of the spiral chamber 212 and the room temperature T2 of the rear chamber 320 of the mechanical pulverizer is preferably 40 to 70 ° C. More preferably, the temperature is 42 to 67 ° C., and further preferably 45 to 65 ° C. from the viewpoint of toner productivity. By controlling the temperature difference ΔT between the temperature T1 and the temperature T2 of the mechanical pulverizer to 40 to 70 ° C., more preferably 42 to 67 ° C., and further preferably 45 to 65 ° C., the surface deterioration of the toner due to heat can be suppressed. And the pulverized raw material can be efficiently pulverized. When the temperature difference ΔT between the temperature T1 and the temperature T2 of the mechanical pulverizer is smaller than 40 ° C., there is a possibility that a short pass is caused without being pulverized, which is not preferable from the viewpoint of toner performance. When the temperature difference ΔT is larger than 70 ° C., it may be excessively pulverized during pulverization, and is not preferable from the viewpoint of toner productivity because it is liable to cause toner surface deterioration or in-machine fusion due to heat.
When the pulverized raw material is pulverized with a mechanical pulverizer, the glass transition point (Tg) of the binder resin is preferably 45 to 75 ° C, more preferably 55 to 65 ° C. Further, it is preferable from the viewpoint of toner productivity that the room temperature T1 of the spiral chamber 212 of the mechanical pulverizer is 0 ° C. or less with respect to Tg and 60 to 75 ° C. lower than Tg. By changing the room temperature T1 of the spiral chamber 212 of the mechanical pulverizer to 0 ° C. or lower and 60 to 75 ° C. lower than Tg, it is possible to suppress the toner surface alteration due to heat, and to efficiently pulverize the pulverized raw material. Can do. The room temperature T2 of the rear chamber 320 of the mechanical pulverizer is preferably 5 to 30 ° C., more preferably 10 to 20 ° C. lower than Tg. By changing the room temperature T2 of the rear chamber 320 of the mechanical pulverizer to 5 to 30 ° C., more preferably 10 to 20 ° C. lower than Tg, the surface deterioration of the toner due to heat can be suppressed, and the pulverized raw material can be efficiently pulverized. can do.

In the present invention, the glass transition point (Tg) of the binder resin was measured using a differential thermal analyzer (DSC measuring device) and DSC-7 (manufactured by Perkin Elmer) under the following conditions.
Sample: 5-20 mg, preferably 10 mg
Temperature curve: Temperature increase I (20 ° C. → 180 ° C., temperature increase rate 10 ° C./min.)
Temperature drop I (180 ° C. → 10 ° C., temperature drop rate 10 ° C./min.)
Temperature increase II (10 ° C. → 180 ° C., temperature increase rate 10 ° C./min.)
Tg measured at the temperature elevation II is taken as the measured value.
Measurement method: Place the sample in an aluminum pan, and use an empty aluminum pan as a reference. The point of intersection between the line of the midpoint of the base line before and after the endothermic peak and the differential heat curve was defined as the glass transition point Tg.

  The tip peripheral speed of the rotating rotor 314 is preferably 80 to 180 m / sec, more preferably 90 to 170 m / sec, and still more preferably 100 to 160 m / sec from the viewpoint of toner productivity. . By setting the peripheral speed of the rotating rotor 314 to 80 to 180 m / sec, more preferably 90 to 170 m / sec, and even more preferably 100 to 160 m / sec, insufficient pulverization and excessive pulverization of the toner can be suppressed. The pulverized raw material can be pulverized efficiently. When the peripheral speed of the rotor is lower than 80 m / sec, a short pass is easily caused without being pulverized, which is not preferable from the viewpoint of toner performance. When the peripheral speed of the rotor 314 is higher than 180 m / sec, the load on the apparatus itself increases, and at the same time, the toner is excessively pulverized at the time of pulverization, and the toner surface is easily deteriorated and fused in the machine. It is not preferable.

  The minimum distance between the rotor 314 and the stator 310 is preferably 0.5 to 10.0 mm, more preferably 1.0 to 5.0 mm, still more preferably 1.0 to 3.0 mm. It is preferable. By setting the distance between the rotor 314 and the stator 310 to 0.5 to 10.0 mm, more preferably 1.0 to 5.0 mm, and still more preferably 1.0 to 3.0 mm, the toner is pulverized. Insufficient or excessive grinding can be suppressed, and the grinding raw material can be efficiently ground. If the distance between the rotor 314 and the stator 310 is larger than 10.0 mm, it is not preferable from the viewpoint of toner performance because a short pass is likely to occur without being pulverized. When the distance between the rotor 314 and the stator 310 is smaller than 0.5 mm, the load on the apparatus itself is increased, and at the same time, the toner is excessively pulverized during pulverization and is liable to cause toner surface deterioration and in-machine fusion. This is not preferable from the viewpoint of toner productivity.

  The magnetic developer used in the present invention preferably has a weight average particle diameter (D4) of 5.0 to 12.0 μm from the viewpoint of resolution and halftone reproducibility. If the weight average particle size of the magnetic developer is less than 5 μm, the magnetic developer is significantly aggregated, which may cause a problem in handling. Further, when the weight average particle diameter of the magnetic developer exceeds 12 μm, the reproduction of a dot latent image or fine line of 100 μm or less may be insufficient.

  The weight average particle size of the magnetic developer was measured using a Coulter Counter TA-II type or Coulter Multisizer II type (manufactured by Coulter Co., Ltd.). 1 Connect a personal computer (manufactured by Canon), and prepare a 1% NaCl aqueous solution using a special grade or first grade sodium chloride as the electrolyte. As a measurement method, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. As the aperture, a 100 μm aperture is used for measuring the toner particle size, and 13 μm is used for measuring the inorganic fine powder particle size. Measure using an aperture. The volume and number of toner and inorganic fine powder were measured, and the volume distribution and number distribution were calculated. Then, the weight-based weight average diameter obtained from the volume distribution, the number% of particles of 4.00 μm or less obtained from the number distribution, and the volume% of particles of 10.08 μm or more obtained from the volume distribution are obtained. The median value of the channels is a representative value for each channel.

  The following channels are used to measure the toner particle size distribution.

  As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm were used.

  When the developing device of the present invention as shown in FIG. 1 is used, the developer is not provided, and the developer is pumped from the hopper chamber 5 from below by the rotary stirring member 6 and directly to the developer carrier 1. In order to supply the developer, the developer is stressed between the rotating stirring member 6 and the developer carrier 1, and the developer adheres to the surface of the developer carrier 1 over a long period of use, so that the sleeve is contaminated or fused. The phenomenon tends to occur. Furthermore, in order to produce a magnetic developer having the above circularity, a method by mechanical pulverization is preferable to a collision type airflow pulverizer, but compared with a magnetic developer pulverized by a collision type airflow pulverizer. The surface of the magnetic developer particles tends to be easily covered with the resin. In addition, the internally added release agent tends to exude on the surface. Therefore, when used in the developing device of the present invention, phenomena such as sleeve contamination and fusion are more likely to occur.

  Therefore, there is a need to improve the roughness of the surface of the developer carrying member 1 by optimizing the roughness.

  As a result of detailed studies, the inventors have found that the developer carrier used in the present invention has an oil sump depth (Rvk) of 2.0 μm or less, which is a roughness parameter, on the surface, and an initial wear height. (Rpk) is 3.0 μm or less, more preferably Rvk is 1.5 μm or less, Rpk is 2.0 μm or less, Rvk is 1.2 μm or less, and Rpk is 2.0 μm or less. It was. As a result, there are no extremely deep and narrow micro-recesses in the resin coating layer, so that the developer does not accumulate in the micro-recesses, and as a result, fusion and contamination are unlikely to occur. In addition, since there are no extremely high and narrow micro-projections, the developer does not get caught on the micro-projections, and as a result, fusion and contamination hardly occur.

  When Rvk exceeds 2.0 μm, a number of extremely deep and narrow micro-recesses are formed, and the magnetic developer is accumulated therein, and defects such as sleeve contamination, image density reduction, and blotch are liable to occur. On the other hand, when Rpk exceeds 3.0 μm, a number of extremely high and narrow fine convex portions are formed, and the magnetic developer is caught in these portions and accumulates with durability, resulting in sleeve contamination, image density reduction, blotch, etc. It is easy for defects to occur.

  This oil sump depth is a characteristic value obtained from the surface roughness curve, and is obtained as follows.

  First, the surface roughness of the developer carrying member is measured in accordance with JIS B0671, and a load curve (BAC) is obtained from the obtained roughness curve. The relationship between the roughness curve and the load curve (BAC) is schematically shown in FIG. In FIG. 6, b1, b2, bi, and bn represent the respective cutting lengths obtained when the roughness curve is cut at a cutting level C parallel to the peak line of the roughness curve, and C represents the roughness curve. It represents the cutting level from the peak, m represents the average line of the roughness curve, L represents the reference length, and tp represents the load length ratio (%) obtained from the formula in FIG.

  Next, as shown in FIG. 7, the straight line having the smallest slope among the straight lines passing through the two points A and B where the difference in load length ratio is 40% on the load curve (BAC) obtained as described above. Select. A point where the straight line intersects the axis with a load length rate of 0% is a point C, and a point where the straight line intersects the axis with a load length rate of 100% is a point D. Further, an intersection point between the cutting height level passing through the point D and the load curve is set as a point E, and an intersection point between the load curve and an axis having a load length rate of 100% is set as a point F. Then, a point G at which the area A2 surrounded by the line segment DE, the curve EF, and the line segment FD is equal to the area of the triangle DEG is obtained on the axis with a load length ratio of 100%. The distance between this point D and point G is Rvk. In the present invention, Rvk is referred to as oil sump depth.

  Next, as shown in FIG. 8, the straight line having the smallest inclination among the straight lines passing through the two points A and B at which the difference in load length ratio is 40% on the load curve (BAC) obtained as described above. Select. A point where this straight line intersects the axis with a load length rate of 0% is defined as a point C. Further, an intersection between the cutting height level passing through the point C and the load curve is defined as a point H, and an intersection between the load curve and an axis having a load length rate of 0% is defined as a point I. Then, a point J at which the area surrounded by the line segment CH, the curve HI, and the line segment IC is equal to the area of the triangle CHJ is obtained on the axis with a load length ratio of 0%. Let Rpk be the distance between this point C and point J. In the present invention, Rpk is referred to as initial wear height.

  For measuring the surface roughness, there is no particular problem if a stylus type roughness meter is used and the method is performed in accordance with JIS B0671.

  Here, the difference between the average line depth Rv and the average line height Rp described in Patent Document 8 will be briefly described. As shown in FIG. 19, the average line depth Rv is obtained by dividing the extracted curve into reference lengths, and for each reference length, the depth from the average line to the deepest valley bottom is Rvi. It is the average value of the depth of Rvi. Therefore, since it does not depend greatly on the number of deep valley bottoms, the number of portions where the developer tends to accumulate is not taken into account, and in the present invention, there is no correlation with sleeve contamination and fusion as much as Rvk.

  As shown in FIG. 20, the average line height Rp was obtained by dividing the extracted curve into reference lengths and setting the height from the average line to the highest peak at each reference length as Rpi. It is the average value of the height Rpi. Therefore, since it does not greatly depend on the number of high peaks, the number of portions where the developer is easily caught is not taken into account, and therefore, in the present invention, there is no correlation with sleeve contamination / fusion as much as Rpk.

  By the way, the surface roughness of the resin coating layer on the surface of the developer carrying member is preferably in the range of 0.1 μm or more and 3.5 μm or less in terms of JIS centerline average roughness (Ra). More preferably, it is 0.3-2.5 micrometers. If Ra is less than 0.1 μm, the charge amount of the magnetic developer on the developer carrying member becomes too high and the developability may be insufficient, and the transportability of the developer to the development area is inferior, It becomes difficult to obtain a sufficient image density. On the other hand, if Ra exceeds 3.5 μm, the magnetic developer layer formed on the developer carrying member may be uneven, which may cause density unevenness on the image.

  Rvk, Rpk, and Ra on the surface of the resin coating layer are measured using a surf coder SE-3500 manufactured by Kosaka Laboratory, with measurement conditions of a cutoff of 0.8 mm, an evaluation length of 4 mm, and a feed rate of 0.5 mm / sec. The measurement was made for 3 points in the axial direction × 3 points in the circumferential direction = 9 points, and the average value was taken.

  Next, the developer carrier used in the present invention will be described.

  Hereinafter, the structure of the resin coating layer in the developer carrier used in the present invention will be described. FIG. 2 is a cross-sectional view schematically showing a part of an example of the developer carrying member used in the present invention. In FIG. 2, a resin coating layer 201 in which a solid lubricant 205, conductive fine particles 203, roughening material or reinforcing particles 202 are dispersed in a binder resin 204 is laminated on a base body 206 made of a metal cylindrical tube. Yes.

  The developer carrier used in the present invention has at least a substrate and a resin coating layer formed on the surface of the substrate.

  The shape and material of the substrate are not particularly limited as long as the resin coating layer can be formed on the surface. Examples of the shape of the base include a cylindrical member, a columnar member, and a belt-like member. As the substrate, for example, when a non-contact developing method is used as an electrostatic latent image carrier (photosensitive drum) as a developing method, a metal cylindrical member is preferably used, and specifically, a metal cylindrical tube is used. Preferably used. As the metal cylindrical tube, nonmagnetic materials such as stainless steel, aluminum and alloys thereof are preferably used.

  As the binder resin used for the resin coating layer, a known resin exhibiting an appropriate film forming property when the layer is formed can be used. For example, thermoplastic resins such as styrene resin, vinyl resin, polyethersulfone resin, polycarbonate resin, polyphenylene oxide resin, polyamide resin, fluorine resin, fiber resin, acrylic resin; epoxy resin, polyester resin, alkyd resin Thermal or photo-curable resins such as phenol resin, melamine resin, polyurethane resin, urea resin, silicone resin, polyimide resin, etc. can be used. Among them, those with releasability such as silicone resin and fluororesin, or excellent mechanical properties such as polyethersulfone, polycarbonate, polyphenylene oxide, polyamide, phenol, polyester, polyurethane, styrene resin, acrylic resin Is more preferable.

In the present invention, the resin coating layer formed on the developer carrying member is fixed on the developer carrying member due to charge-up, or the developer carrying member generated when the magnetic developer is charged up. In order to prevent poor charging from the surface of the magnetic developer to the magnetic developer, it is desirable to be conductive. In addition, the volume resistance value of the resin coating layer is preferably 10 ⁴ Ω · cm or less, more preferably 10 ³ Ω · cm or less. If the volume resistance value of the resin coating layer exceeds 10 ⁴ Ω · cm, poor charge application to the magnetic developer is likely to occur, and as a result, blotch is likely to occur.

  The resin coating layer has a volume resistance of 7 μm to 20 μm formed on a 100 μm thick PET sheet, and a four-terminal probe using a resistivity meter Loresta AP or Hiresta IP (both manufactured by Mitsubishi Chemical). It can measure by using. The measurement environment is 20 to 25 ° C. and 50 to 60% RH.

  In this invention, in order to adjust the resistance value of a coating layer to said value, it is preferable to contain the electroconductive substance mentioned below in a coating layer. Examples of the conductive material used at this time include metal powders such as aluminum, copper, nickel, and silver, metal oxides such as antimony oxide, indium oxide, and tin oxide, carbon fiber, carbon black, and graphite. Examples include carbon materials. In the present invention, among these, carbon black, in particular conductive amorphous carbon, is particularly excellent in electrical conductivity, and it can be filled with a polymer material to impart conductivity, or only by controlling the amount of addition. Since arbitrary conductivity can be obtained to some extent, it is preferably used. Moreover, it is preferable to make the addition amount of these electroconductive substances suitable in this invention into the range of 1-100 mass parts with respect to 100 mass parts of binder resin.

  Furthermore, in the present invention, a solid lubricant can be mixed in the coating layer in order to further reduce the adhesion of the developer to the surface of the developer carrying member. Examples of the solid lubricant that can be used in this case include molybdenum disulfide, boron nitride, graphite, graphite fluoride, silver-selenium niobium, calcium chloride-graphite, and talc. Of these, crystalline graphite or graphitized particles made of natural graphite are preferably used in the present invention.

  Crystalline graphite used in the present invention can be broadly divided into natural graphite and artificial graphite. Natural graphite is produced from the ground by being completely graphitized by natural geothermal heat for a long time and underground high pressure. To do. Artificial graphite, for example, is obtained by hardening pitch coke with tar pitch or the like and firing and carbonizing it at about 1,000 to 1,300 ° C., impregnating into various pitches, and placing it in a graphitization furnace. By processing at a high temperature of about 1,000 ° C., carbon crystals are grown and converted into graphite. These graphites are pulverized and classified to obtain graphite having a desired particle size.

  Graphitized particles have a slightly lower degree of graphitization than crystalline graphite, but also have high conductivity and lubricity, and the shape of the particles is massive or roughly spherical, and the hardness of the particles themselves is comparable. The characteristic is that it is very expensive. Therefore, it has the characteristic that it is excellent in abrasion resistance than the said graphite.

  As a method for obtaining such graphitized particles, there is a method using bulk mesophase pitch and mesocarbon microbeads as raw materials.

  As a method for obtaining bulk mesophase pitch, β-resin is extracted from coal tar pitch or the like by solvent fractionation, and this is hydrogenated and heavyized, or further finely pulverized, and then benzene or toluene or the like. There is a method obtained by removing solvent-soluble components. Next, the bulk mesophase pitch is finely pulverized and heat-treated in air at about 200 ° C. to 350 ° C. to be lightly oxidized. Next, the oxidized bulk mesophase pitch is carbonized by primary firing at about 800 to 1,200 ° C. in an inert atmosphere such as nitrogen or argon, followed by about 2,000 to 3,500 ° C. Then, the desired aggregated graphitized particles can be obtained by secondary firing.

A typical method for obtaining mesocarbon microbeads, which are another preferred raw material for obtaining graphitized particles, is, for example, a coal-based heavy oil or a petroleum-based heavy oil at a temperature of 300 to 500 ° C. After heat treatment and polycondensation to produce crude mesocarbon microbeads, the reaction product is subjected to filtration, stationary sedimentation, centrifugation, etc. to separate the mesocarbon microbeads, followed by benzene, toluene, There is also a method using mesocarbon microbeads obtained by washing with a solvent such as xylene and further drying.
As a method of graphitizing using the above mesocarbon microbeads, firstly, the mesocarbon microbeads after drying are mechanically dispersed primarily with a gentle force that does not cause destruction. Is preferable for preventing coalescence and obtaining uniform particle size.

  The mesocarbon microbeads after the primary dispersion are subjected to primary heat treatment at a temperature of 200 to 1,500 ° C. in an inert atmosphere and carbonized. In order to prevent coalescence of the particles after graphitization and obtain a uniform particle size, it is preferable that the carbide after the primary heat treatment is mechanically dispersed with a mild force that does not destroy the carbide. The carbide after the secondary dispersion treatment is subjected to secondary heat treatment at about 2,000 to 3,500 ° C. in an inert atmosphere to obtain desired substantially spherical graphitized particles.

  The addition amount of these solid lubricants suitable in the present invention is preferably in the range of 1 to 100 parts by mass with respect to 100 parts by mass of the binder resin.

  As a means for dispersing the conductive substance and the solid lubricant into the binder resin, a conventionally known dispersing device using beads such as a sand mill, a paint shaker, a dyno mill, a pearl mill, or the like can be used.

  However, for example, when a solid lubricant or conductive fine particles having a large specific gravity difference or a high cohesiveness or a small particle diameter are dispersed with a coating resin dissolved in a solvent, fine powder due to insufficient dispersion or excessive dispersion. Due to the increase, the particle size distribution of the conductive substance or solid lubricant in the paint tends to be wide, and it is difficult to make Rvk and Rpk suitable values when a coating layer is formed using these paints. There are cases.

  Thus, it has been found that by using a device that has at least two ring-shaped discs arranged opposite to each other and finely disperses them through the gap, it is possible to more suitably disperse the paint with a uniform particle size distribution. .

  An example of such a dispersing machine is shown in FIGS. These are merely examples and are not limiting. FIG. 10 is a partially cutaway longitudinal sectional view of an apparatus according to the present invention. FIG. 11 is a schematic vertical sectional view of an essential part of the disperser shown in FIG. As shown in FIGS. 10 to 11, the disperser covers the first holder 311, the second holder 321 disposed in front (upward) of the first holder 311, and the first holder 311 together with the second holder 321. A case 303, a supply mechanism P such as a pump for supplying the dispersion liquid to the apparatus, and a contact pressure applying mechanism 304 are provided. The first holder 311 is provided with a first processing ring 310 and a rotating shaft 350. The first processing ring 310 is a metal annular body called a mating ring (shown in FIG. 12), and includes a first processing surface 301 that is mirror-finished. The rotating shaft 350 is fixed to the center of the first holder 311 by a fixing tool 351 such as a bolt, and an end portion thereof is connected to a rotation driving device 305 (rotation driving mechanism) such as an electric motor. The driving force 305 is transmitted to the first holder 311 and the first holder 311 is rotated. The first processing ring 310 is attached to the front part (upper part) of the first holder 311 concentrically with the rotation shaft 350, and rotates integrally with the first holder 311 by the rotation of the rotation shaft 350. The first processing surface 301 is exposed from the first holder 311 and faces the second holder 321 side. The first processing surface 301 is preferably subjected to mirror processing such as polishing, lapping, and polishing. As the material of the first processing ring 310, ceramic, sintered metal, wear-resistant steel, or other metal subjected to hardening treatment, or hard material subjected to lining, coating, plating, or the like is employed. In particular, since it rotates, it is desirable to form the first processing ring 310 with a lightweight material. The case 303 is a bottomed container having a discharge part 332, and the first holder 311 is accommodated in the internal space 330.

  The second holder 321 is provided with a second processing ring 320, a liquid dispersion introduction part 322, and a contact pressure applying mechanism 304.

  The second processing ring 320 is a metal annular body (shown in FIG. 12) called a compression ring, and is a mirror-finished second processing surface 302 and the second processing surface 302 positioned inside the second processing surface 302. A pressure receiving surface 323 (hereinafter referred to as a separation adjusting surface 323) adjacent to the processing surface 302 is provided. As illustrated, the separation adjusting surface 323 is an inclined surface. The mirror surface processing applied to the second processing surface 302 employs the same method as the first processing surface 301. Further, the same material as that of the first processing ring 310 is also used for the material of the second processing ring 320. The separation adjusting surface 323 is adjacent to the inner peripheral surface of the annular second processing ring 320.

  The contact surface pressure applying mechanism 304 presses the second processing surface 302 against the first processing surface 301 in a pressure contact state or a close state, and fluid pressure (pressure of the liquid to be dispersed generated by a supply mechanism such as a pump). ) And the like to generate the microfluidic film by balancing with the force separating the two processing surfaces 301 and 302 (in other words, the interval between the processing surfaces 301 and 302 is kept at a very small interval).

  Specifically, in this embodiment, the contact surface pressure applying mechanism 304 includes an accommodating portion 341, a spring receiving portion 342 provided at the back (deepest portion) of the accommodating portion 341, a spring 343, and an air introducing portion 344. It consists of and.

  However, the contact surface pressure applying mechanism 304 only needs to include at least one of the housing portion 341, the spring receiving portion 342, the spring 343, and the air introducing portion 344.

  The storage portion 341 is provided with the second processing ring 320 so that the position of the second processing ring 320 in the storage portion 341 can be displaced deeply or shallowly (up and down). One end of the spring 343 contacts the back of the spring receiving part 342, and the other end of the spring 343 contacts the front part (upper part) of the second processing ring 320 in the housing part 342. Although only one spring 343 is depicted in FIG. 10, it is preferable that each part of the second processing ring 320 is pressed by a plurality of springs. That is, by increasing the number of springs 343, a more uniform pressing force can be applied to the second processing ring 320. Therefore, it is preferable that several to several tens of springs 343 are attached to the second holder 321.

  In FIG. 11, as described above, it is possible to introduce a pressurized gas such as air into the housing portion 341 from the other at the air introduction portion 344. By introducing such a pressurized gas typified by air, a pressure chamber is provided between the accommodating portion 341 and the second processing ring 320, and air pressure is given to the second processing ring 320 as a pressing force together with the spring 343. Can do. Therefore, by adjusting the air pressure introduced from the air introduction part 344, it is possible to adjust the contact pressure of the second processing surface 302 with respect to the first processing surface 301 even during operation. In addition, instead of the air introduction part using air pressure, other fluid pressures such as oil pressure may be used, but the present invention is not limited to these.

  The contact surface pressure applying mechanism 304 supplies and adjusts a part of the above pressing force (contact surface pressure), and also serves as a displacement adjustment mechanism and a buffer mechanism. Specifically, the contact surface pressure application mechanism 304 can maintain the initial pressing force by adjusting the air pressure to the axial displacement caused by the elongation or wear in the axial direction during starting or during operation as a displacement adjusting mechanism. Further, as described above, the contact surface pressure applying mechanism 304 also functions as a buffer mechanism for fine vibration and rotational alignment by adopting a floating mechanism that holds the second processing unit 320 in a displaceable manner.

  Further, even if there is a margin between the upper part of the second processing ring 320 and the uppermost part of the housing part 341 in the housing part 341, the spring 343 defines the upper limit of the width of the gap between the processing surfaces 301 and 302. To do. That is, it functions as a separation inhibiting unit that inhibits separation of both processing surfaces 301 and 302.

  Further, even if the processing surfaces 301 and 302 are not in contact with each other, the spring 343 defines the lower limit of the width of the gap between the processing surfaces 301 and 302. That is, it functions as a proximity deterring unit that deters the proximity of both processing surfaces 301 and 302.

  An example of such an apparatus is Claire Essfive (M Technique Co., Ltd.).

  Next, the case where the apparatus according to the present invention is used as a disperser for the fine particles contained in the developer carrier resin coating layer will be described in more detail.

  The mixture constituting the resin coating layer described above receives a constant pressure from the supply mechanism P and is introduced into the sealed internal space of the case 303 via the introduction part 322. However, the above-mentioned mixture that is the liquid to be dispersed may be introduced from a plurality of paths, and the resin coating layer constituting material may be introduced through different paths depending on the characteristics of the material. On the other hand, the first processing ring 310 is rotated by the rotation drive device 305 (rotation drive mechanism). As a result, the first processing surface rotates relative to the second processing surface in a state where a minute interval is maintained. The mixture introduced into the internal space of the case 303 forms a fluid film between the processing surfaces 301 and 302 that are kept at a minute distance, and is strongly sheared between the second processing surface 302 by the rotation of the first processing surface 301. In this way, a resin coating for forming a surface layer having a desired dispersion is obtained. The obtained surface layer forming resin paint is discharged from the discharge portion 332. Thereby, the particle size distribution of the particles in the paint is made more uniform, and as a result, it becomes easier to set the aforementioned Rvk and Rpk to suitable values.

  A coefficient of variation can be used as an index representing the uniformity of the particle size distribution of the paint. This is measured as follows.

  In a Coulter LS-230 type particle size distribution meter (manufactured by Coulter, Inc.) of a laser diffraction type particle size distribution meter, isopropyl alcohol is used as a solvent for measurement, and 2 to 20 mg of a measurement sample is added to 100 to 150 ml of the solvent, and ultrasonic waves are obtained. The dispersion treatment was performed for about 1 to 3 minutes with a disperser, and the measurement was performed. Then, the volume average diameter Dv and the coefficient of variation A derived from the volume distribution were obtained. The coefficient of variation A was calculated by S / Dv (S: standard deviation of volume distribution, Dv: volume average particle diameter).

  Further, in the present invention, the wear resistance of the coating layer of the developer carrier is improved, and further, the surface of the coating layer is kept uniform, and at the same time, a certain degree of protrusion is provided on the surface of the coating layer. Thus, spherical particles can be added in order to suppress the load caused by the contact between the surface of the coating layer and the magnetic developer and to make it difficult to cause magnetic developer fusion and magnetic developer contamination.

  The spherical particles have a volume average particle size of 0.3 to 30 μm, preferably 1 to 20 μm, more preferably 3 to 15 μm. If the volume average particle size of the spherical particles is less than 0.3 μm, the effect of imparting a uniform and sufficient roughness to the surface is poor, and the charge of the magnetic developer due to wear of the coating layer, magnetic developer contamination, and magnetic developer fusion Causing ghost deterioration and image density reduction. When the volume average particle size exceeds 30 μm, the surface roughness of the conductive coating layer becomes too large, and it becomes difficult to sufficiently charge the magnetic developer, and the mechanical strength of the coating layer decreases. . The spherical shape in the present invention preferably has a ratio of major axis / minor axis of particles of 1.0 to 1.5 (preferably 1.0 to 1.2). In particular, spherical particles are preferable.

  As the spherical particles used in the present invention, known spherical particles can be used. For example, there are spherical resin particles, spherical metal oxide particles, spherical carbonized particles, and the like, which are appropriately used according to the developability of the magnetic developer and the development system.

  As the spherical resin particles, for example, spherical resin particles by suspension polymerization method, dispersion polymerization method or the like are used. Spherical resin particles can have a suitable surface roughness with a smaller addition amount, and a uniform surface shape can be easily obtained. Examples of such spherical resin particles include acrylic resin particles such as polyacrylate and polymethacrylate, polyamide resin particles such as nylon, polyolefin resin particles such as polyethylene and polypropylene, silicone resin particles, phenolic resin particles, Examples include polyurethane resin particles, styrene resin particles, benzoguanamine particles, and the like. The resin particles obtained by the pulverization method may be used after thermally or physically spheroidizing.

For example, an inorganic fine powder may be adhered to or adhered to the surface of the spherical resin particles. Examples of such inorganic fine powder include SiO ₂ , SrTiO ₃ , CeO ₂ , CrO, Al ₂ O ₃ , ZnO, MgO, oxides such as Si ₃ N ₄ , carbides such as SiC, CaSO ₄ , Examples thereof include sulfates and carbonates such as BaSO ₄ and CaCO ₃ .

  Such inorganic fine powder may be used after being treated with a coupling agent. In particular, it can be preferably used for the purpose of improving the adhesion to the binder resin, or for imparting hydrophobicity to the particles. Examples of such a coupling agent include a silane coupling agent, a titanium coupling agent, and a zircoaluminate coupling agent. More specifically, for example, as a silane coupling agent, hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, Benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethyl Diethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltet Lamethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and dimethyl containing 2 to 12 siloxane units per molecule, each containing a hydroxyl group bonded to one silicon atom at each terminal unit Polysiloxane etc. are mentioned.

  By treating the surface of the spherical resin particles with inorganic fine powder in this way, dispersibility in the paint, uniformity of the coating surface, stain resistance of the coating layer, charge imparting property to the magnetic developer, coating The wear resistance of the layer can be improved.

  Further, by imparting electrical conductivity to the spherical particles, charges are less likely to accumulate on the particle surface due to the electrical conductivity, and it is possible to reduce adhesion of the magnetic developer and improve the charge imparting property of the magnetic developer. As a method for obtaining such conductive spherical particles, the following methods are preferable, but are not necessarily limited to these methods.

As a method for obtaining particularly preferable conductive spherical particles used in the present invention, resin-based spherical particles such as phenol resin, naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer, polyacrylonitrile, etc. Low density and good conductivity spherical carbon particles obtained by carbonizing and / or graphitizing particles and mesocarbon microbeads by firing, more preferably phenol resin, naphthalene resin, furan resin, xylene resin, divinyl The surface of spherical particles such as benzene polymer, styrene-divinylbenzene copolymer, polyacrylonitrile, etc. is coated with bulk mesophase pitch by mechanochemical method, heat-treated in an oxidizing atmosphere, and then fired to carbonize and / or graphite. It is the conductive spherical carbon particle obtained by making it. The spherical carbon particles obtained by these methods can control the conductivity to some extent by changing the firing conditions and the like in any method. In addition, the spherical carbon particles obtained by these methods are optionally plated with a conductive metal and / or metal oxide so that the true density does not exceed ³ g / cm ³ in order to further increase the conductivity. May be.

  As another method for obtaining conductive spherical particles preferably used in the present invention, conductive fine particles smaller than the particle diameter of the core particles are mechanically mixed on the surface of the core particles made of spherical resin particles at an appropriate blending ratio. Then, after the conductive fine particles are uniformly attached around the resin particles by the action of van der Waals force and electrostatic force, the surface of the resin particles is softened by the local temperature rise caused by, for example, mechanical impact force. Examples thereof include conductively treated spherical resin particles formed with fine particles. As the constituent material of the mother particles, it is preferable to use a resin which is a spherical organic compound having a low core density. For example, PMMA, acrylic resin, polybutadiene resin, polystyrene resin, polyethylene, polypropylene, polybutadiene, or a combination thereof. Resin particles such as a polymer, a benzoguanamine resin, a phenol resin, a polyamide resin, nylon, a fluorine resin, a silicone resin, an epoxy resin, and a polyester resin can be used. Further, as the conductive fine particles which are small particles, the particle size of the small particles is preferably 1/8 or less than the particle size of the mother particles in order to uniformly coat the conductive fine particles.

  As still another method for obtaining conductive spherical particles preferably used in the present invention, conductive fine particles are uniformly dispersed in spherical resin particles. For example, conductive fine particles are dispersed in a binder resin. After kneading, pulverize to the prescribed particle size, and add spherical initiator particles, conductive initiators and other additives to the polymerizable monomer. The conductive fine particles obtained by suspending the monomer composition uniformly dispersed by a disperser or the like in a water phase containing a dispersion stabilizer so as to have a predetermined particle diameter by a stirrer or the like and performing polymerization Examples include dispersed spherical particles.

  The conductive fine particle-dispersed spherical particles obtained by these methods are mechanically mixed with the conductive fine particles having a particle size smaller than the above-mentioned core particles at an appropriate blending ratio, and conductive by van der Waals force and electrostatic force. After the conductive fine particles are uniformly attached around the conductive fine particle-dispersed spherical particles, the surface of the conductive fine particle-dispersed resin particles is softened by a local temperature rise caused by, for example, a mechanical impact force, and the conductive fine particles are formed, Further, the conductivity may be increased for use.

  The particle size of these spherical particles was also measured by the same method as the particle size distribution of the paint.

  In the resin coating layer of this invention, a charge control agent can be contained as needed. As the charge control agent, those similar to those used for the magnetic developer particle formation described above can be used.

  When a negatively chargeable magnetic developer is used as the magnetic developer in the present invention, the conductive resin coating of the developer carrying member as disclosed in Japanese Patent Application Laid-Open No. 2002-31636 or Japanese Patent Application Laid-Open No. 2003-057951 The layer may contain a charge-controllable nitrogen-containing compound. In this case, it is preferable that the nitrogen-containing compound is a quaternary ammonium salt compound that is positively charged with respect to iron powder. It is preferable in terms of good charge imparting property to the developer. At this time, the resin coating layer preferably has at least one of an amino group, ═NH group, and —NH— bond in the resin structure in terms of good charge imparting property to the magnetic developer. .

  Here, the relationship between the magnetic developer and the resin coating layer in the developing device will be described. When the magnetic developer is used as a negatively chargeable magnetic developer, for example, since it has a strong negative chargeability compared to a conventional magnetic developer, the magnetic developer has high chargeability, uniform charge amount, and charging characteristics. Environmental stability can be achieved, but magnetic developer fusion and charge-up are likely to occur. Therefore, also in the present invention, by adding the quaternary ammonium salt compound to the resin coating layer, combined with effects such as charge imparting to the resin coating layer by the graphitized particles having a specific degree of graphitization, lubricity and the like. In particular, it is possible to obtain high charging stability and conveyance stability with respect to the magnetic developer that is particularly prone to charge-up and the like. As a result, it is possible to maintain the high charging stability of the magnetic developer and to provide a high-definition image having environmental stability and long-term stability.

  In the present invention, if the binder resin in the resin coating layer is configured as described above, there is no clear reason why the resin coating layer becomes a good charge imparting substance for the magnetic developer. Is estimated as follows.

  When added to the binder resin, the quaternary ammonium salt compound that is positively charged with respect to iron powder itself contains at least one of an amino group, ═NH, or —NH— in the structure. The binder resin is uniformly dispersed in the binder resin and further taken into the structure of the binder resin when the resin coating layer is formed, so that the binder resin composition itself having the compound has a negative chargeability. It is considered a thing.

  For this reason, the resin coating layer works to prevent the negative charge amount of the magnetic developer from becoming excessive with respect to the negatively chargeable magnetic developer. As a result, the negative charge amount of the magnetic developer is appropriately controlled. It becomes possible to do.

  The triboelectric charge amount between the negatively chargeable magnetic developer and the resin coating layer of the developer carrier was measured with a surface charge amount measuring apparatus (TS100AS manufactured by Toshiba Chemical Corporation) as shown in FIG. A crushed material of negatively chargeable magnetic developer is sieved with a mesh, and a binder resin containing particles remaining between 60 mesh and 100 mesh and a quaternary ammonium salt compound that is positively charged with respect to iron powder. What applied to the SUS board was used. FIG. 5 is a graph showing the relationship between the charge amount of the model magnetic developer and the addition amount of the quaternary ammonium salt compound to the binder resin used in the resin coating layer of the present invention. As shown in FIG. 4, in the PMMA resin that does not contain an amino group, ═NH or —NH— in the structure, no change in charge amount due to addition is observed.

  The quaternary ammonium salt compound may be any compound as long as it has a positive chargeability with respect to iron powder, and examples thereof include compounds represented by the following general formula.

（式中のＲ₁、Ｒ₂、Ｒ₃及びＲ₄は、夫々置換基を有してもよいアルキル基、置換基を有してもよいアリール基、アルアルキル基を表し、Ｒ₁〜Ｒ₄は夫々同一でも或いは異なっていても良い。Ｘ^-は酸の陰イオンを表す。）

(Wherein R ₁ , R ₂ , R ₃ and R ₄ represent an alkyl group which may have a substituent, an aryl group which may have a substituent, and an aralkyl group, respectively, R _{1 to} R ₄ may be the same or different, and X ⁻ represents an anion of an acid.)

In the aforementioned general formula, specific examples of the acid ion of X 2 ⁻ include organic sulfate ion, organic sulfonate ion, organic phosphate ion, molybdate ion, tungstate ion, heteropolyacid ion containing molybdenum atom or tungsten atom, etc. Is preferably used.

  On the other hand, for example, a fluorine-containing quaternary ammonium salt compound having a negative chargeability with respect to iron powder as represented by the following structural formula was also studied. It has been found that the intended purpose of the present invention is not achieved. That is, since the compound represented by the following structural formula has a fluorine atom having a strong electron-withdrawing property in the structure, the compound itself has a negative chargeability with respect to the iron powder. Even if the compound is dispersed in a binder resin containing at least one of an amino group, = NH or -NH- in the structure, and this is heat-cured to form a resin coating layer on the developer carrier, To the extent that it is used for a binder resin containing the quaternary ammonium salt compound containing no fluorine, the overcharge suppression property against the negatively chargeable magnetic developer was not obtained.

  Specific examples of the quaternary ammonium salt compound suitably used in the present invention include the following, but of course, the present invention is not limited thereto.

  The amount of the quaternary ammonium salt compound as exemplified above is 1 to 100 parts by mass with respect to 100 parts by mass of the binder resin containing at least one of an amino group, ═NH or —NH— in the structure. It is preferable that If the amount is less than 1 part by mass, the charge imparting property may not be improved by addition. If the amount exceeds 100 parts by mass, the dispersion in the binder resin becomes poor and the coating strength tends to decrease.

  As the binder resin containing at least one of an amino group, = NH or -NH- in the structure, a phenol resin, a polyamide resin, and a polyamide produced using a nitrogen-containing compound as a catalyst in the production process are curing agents. Examples thereof include an epoxy resin, a urethane resin, and a copolymer partially containing these resins. The quaternary ammonium salt compound is easily taken into the structure of the binder resin when forming a mixture with these binder resins.

  Examples of the nitrogen-containing compound used as the catalyst include ammonium salts such as ammonium sulfate, ammonium phosphate, ammonium sulfamate, ammonium carbonate, ammonium acetate, and ammonium maleate, and amine salts. Basic catalysts include ammonia; dimethylamine, diethylamine, diisopropylamine, diisobutylamine, diamylamine, trimethylamine, triethylamine, tri-n-butylamine, triamylamine, dimethylbenzylamine, diethylbenzylamine, dimethylaniline, diethylaniline, N , N-di-n-butylaniline, N, N-diamilaniline, N, N-di-t-amylaniline, N-methylethanolamine, N-ethylethanolamine, diethanolamine, triethanolamine, dimethylethanolamine , Diethylethanolamine, ethyldiethanolamine, n-butyldiethanolamine, di-n-butylethanolamine, triisopropanolamine, ethylenediamine, hexamethyl Amino compounds such as lentetramine; pyridine and derivatives thereof such as pyridine, α-picoline, β-picoline, γ-picoline, 2,4-lutidine, 2,6-lutidine; quinoline compounds, imidazole, 2-methylimidazole, 2 , 4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, imidazole such as 2-heptadecylimidazole, and nitrogen-containing heterocyclic compounds such as derivatives thereof. Can be mentioned.

  Examples of the polyamide resin used as the binder resin described above include nylon 6, 66, 610, 11, 12, 9, 13, Q2 nylon, etc., and a nylon copolymer mainly composed of these, N- Examples thereof include alkyl-modified nylon and N-alkoxylalkyl-modified nylon, and any of them can be suitably used. Furthermore, any resin containing a polyamide resin such as various resins modified with polyamide such as a polyamide-modified phenol resin or an epoxy resin using a polyamide resin as a curing agent may be used. It can be used suitably.

  In addition, as the urethane resin used as the binder resin described above, any resin including a urethane bond can be suitably used. This urethane bond is obtained by polymerization addition reaction of polyisocyanate and polyol.

  The polyisocyanate used as the main raw material for this polyurethane resin is TDI (tolylene diisocyanate), pure MDI (diphenylmethane diisocyanate), polymeric MDI (polymethylene polyphenyl polyisocyanate), TODI (tolidine diisocyanate), NDI (naphthalene diisocyanate), etc. Aromatic polyisocyanates such as: HMDI (hexamethylene diisocyanate), IPDI (isophorone diisocyanate), XDI (xylylene diisocyanate), hydrogenated XDI (hydrogenated xylylene diisocyanate), aliphatic MDI (dicyclohexylmethane diisocyanate), etc. And polyisocyanates.

  Polyols that are the main raw materials for this polyurethane resin include polyether polyols such as PPG (polyoxypropylene glycol), polymer polyol, polytetramethylene glycol (PTMG); polyester polyols such as adipate, polycaprolactone, and polycarbonate polyol. Polyether modified polyols such as PHD polyol and polyether ester polyol; other epoxy-modified polyols; partially saponified polyols of ethylene-vinyl acetate copolymer (saponified EVA); flame retardant polyols and the like.

  In the present invention, the resin coating layer of the developer carrying member may contain an unsubstituted or substituted benzylic acid metal compound represented by the following general formula (B). It is preferable that the acid metal compound is the aluminum compound of benzyl acid from the viewpoint of good charge imparting property to the magnetic developer.

（式中、Ｒ₁とＲ₂は同一であっても異なっていても良く、それぞれ独立して、直鎖又は分岐したアルキル基、直鎖又は分岐したアルケニル基、直鎖又は分岐したアルコキシル基、ハロゲン原子、ニトロ基、シアノ基、アミノ基、カルボキシル基及び水酸基からなるグループから選ばれる置換基を示し、ｍ及びｎは０〜５の整数を示す。）

(In the formula, R ₁ and R ₂ may be the same or different, and each independently represents a linear or branched alkyl group, a linear or branched alkenyl group, a linear or branched alkoxyl group, A substituent selected from the group consisting of a halogen atom, a nitro group, a cyano group, an amino group, a carboxyl group and a hydroxyl group is shown, and m and n are integers of 0 to 5.)

  Further, the aluminum compound of benzyl acid is preferably an aluminum compound of benzyl acid represented by the following general formula (B-1), but if it is a complex and / or complex salt composed of 2 mol of benzyl acid and 1 mol of aluminum atom. It is not limited to the general formula (B-1).

（式中、Ｒ₁とＲ₂は同一であっても異なっていても良く、各々独立して、直鎖又は分岐したアルキル基、アルケニル基、アルコキシル基、ハロゲン原子、ニトロ基、シアノ基、アミノ基、カルボキシル基及び水酸基からなるグループから選ばれる置換基を示し、ｍ及びｎは０乃至５の整数を示す。また、Ｘ⁺は１価のカチオンを示し、Ｘは水素、リチウム、ナトリウム、カリウム、アンモニウム又はアルキルアンモニムを表す。）

(In the formula, R ₁ and R ₂ may be the same or different, and each independently represents a linear or branched alkyl group, alkenyl group, alkoxyl group, halogen atom, nitro group, cyano group, amino group. A substituent selected from the group consisting of a group, a carboxyl group and a hydroxyl group, m and n are each an integer of 0 to 5. X ⁺ is a monovalent cation, X is hydrogen, lithium, sodium, potassium Represents ammonium or alkylammonium.)

  Other examples of the aluminum compound of benzylic acid include an aluminum complex and / or complex salt in which one molecule of benzylic acid is coordinated, an aluminum complex and / or complex salt in which three molecules of benzylic acid are coordinated, and benzylic acid A mixture of an aluminum complex and / or a complex salt in which 1 to 3 molecules of the compound are coordinated can also be used.

  The number of carbon atoms of the substituents represented by the general formulas (B) and (B-1) is not particularly limited, but is in the range of (0 to 12). Or from the viewpoint of dispersibility in the resin coating layer.

  The aluminum compound of benzyl acid was obtained, for example, by mixing an unsubstituted or substituted benzyl acid as described above and an aluminum salt such as aluminum sulfate in a desired molar ratio and heating and reacting in an alkaline atmosphere. The precipitate can be collected by filtration, washed with water and dried. However, the method for producing the aluminum compound of benzyl acid according to the present invention is not limited to this.

  The aluminum compound of benzyl acid dispersed in the resin coating layer has an effect of suppressing the charge amount for a negative magnetic developer having a high charge amount, and is suitable for a negatively chargeable magnetic developer. Can provide a uniform charge amount. As a result, image density reduction, sleeve ghosting, fogging, and the like can be prevented, and blotting due to charge-up can be more effectively prevented.

  As content of the aluminum compound of benzyl acid currently disperse | distributed in the said resin coating layer, it is 1-100 mass parts with respect to 100 mass parts of binder resin, More preferably, it is 2-50 mass parts. When the addition amount is less than 1 part by mass, the effect of the addition may be insufficient, and when it exceeds 100 parts by mass, the environmental stability of the resin coating layer may be insufficient.

  As a method for forming these materials as a resin coating layer on the developer carrying member, it is possible to form the materials by a generally known method such as a spray method or a dipping method. In general, in the air spray method, a coating layer with good dispersion can be obtained by stably forming a paint into fine particle droplets, which is preferable as a method for forming a resin coating layer used for producing the developer carrier of the present invention. .

  Such an air spray method includes a needle type air spray gun shown in FIG. 13 and a type of spray gun which blows air from a concentric hole around the nozzle tip shown in FIG.

  However, when the needle type spray gun 601 model manufactured by Binks Corporation shown in FIG. 13 is used, the paint stays in the vicinity of the needle portion, and the aggregates generated by the reaggregation of the particles may adhere to the coating layer.

  In addition, when a nozzle of the type that blows air from a concentric hole at the nozzle tip as shown in FIG. 14 is used, if the particle size distribution of the paint is wide, fine particle formation becomes insufficient, and dispersion is uneven due to re-aggregation and separation of fine particles. It may become a new layer.

  Therefore, as a method of forming the resin coating layer of the developer carrying member of the present invention, a spray gun for atomizing a paint using a swirling air flow discharged from a spiral hole as shown in FIG. The method using is more preferable. Compared with the case where air discharged from concentric holes is used, this method can also make the paint of relatively high viscosity fine particles, and also when the viscosity of the paint is relatively low and the discharge amount is large. The paint can be stably made into solid fine particles, and the coating latitude is greatly expanded. In addition, even when solid fine particles with high cohesion are dispersed in the paint, the latitude of the conditions for atomization of the paint is wide, so it is easy to prevent reaggregation of the solid fine particles, and the solid in the coating layer to be formed It is possible to obtain a resin film having a high dispersion of fine particles and no dispersion or separation of the fine particles and a uniform dispersion. It was found to be particularly effective for optimizing Rvk.

  In the developing method using a magnetic developer, a magnetic field generating means such as a magnet roller constituted by a magnet is provided in the developer carrying body in order to magnetically attract and hold the magnetic developer on the developer carrying body. Deploy. In that case, the substrate may be cylindrical, and a magnet roller may be disposed therein.

  The binder resin for magnetic developer used in the magnetic developer of the present invention includes polyester resin, styrene-acrylic resin, hybrid resin containing polyester resin component and styrene-acrylic resin component, epoxy resin, styrene-butadiene. Resins, polyurethane resins, and the like can be mentioned, but there is no particular limitation, and conventionally known resins can be used. Of these, polyester resins and hybrid resins are particularly preferred from the standpoint of fixing properties.

  The polyester resin is a resin formed by polycondensation of a polyhydric alcohol and a polybasic acid, and examples of the monomer of the polyester resin component include the following.

  Examples of the divalent alcohol component include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1, 6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, bisphenol derivatives represented by the following formula (a), and diols represented by the following formula (a): Can be mentioned.

  Divalent carboxylic acids include benzene dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and phthalic anhydride, or anhydrides thereof; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, or anhydrides thereof. A succinic acid substituted with an alkyl group having 6 to 18 carbon atoms or an anhydride thereof; an unsaturated dicarboxylic acid such as fumaric acid, maleic acid, citraconic acid, itaconic acid, or an anhydride thereof;

  Other monomers of the polyester resin include glycerin, pentaerythritol, sorbit, sorbitan, and polyhydric alcohols such as oxyalkylene ethers of novolak type phenol resins; trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid And polyhydric carboxylic acids such as anhydride thereof.

  The styrene-acrylic resin is a resin produced by addition polymerization of a styrene monomer and an acrylic acid monomer, and examples of vinyl monomers for producing a styrene-acrylic resin include the following. .

  Styrene monomers include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-phenyl styrene, p-ethyl styrene, 2,4-dimethyl styrene, pn-butyl styrene, p-tert. -Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-chlorostyrene, 3 Styrene and its derivatives such as 1,4-dichlorostyrene, m-nitrostyrene, o-nitrostyrene, p-nitrostyrene.

  Examples of acrylic monomers include acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, acrylic acid-n-butyl, acrylic acid isobutyl, acrylic acid-n-octyl, acrylic acid dodecyl, acrylic acid-2- Acrylic acid and acrylic esters such as ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, methacrylic acid-n-butyl, methacrylic acid Such as isobutyl acid, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate And α- methylene aliphatic monocarboxylic acids and esters thereof, acrylonitrile, methacrylonitrile, and the like such as acrylic acid or methacrylic acid derivatives of acrylamide.

  Furthermore, as a monomer of styrene-acrylic resin, acrylic acid or methacrylic acid esters such as 2-hydroxylethyl acrylate, 2-hydroxylethyl methacrylate, 2-hydroxylpropyl methacrylate, 4- (1-hydroxy-1-methylbutyl) Examples thereof include monomers having a hydroxyl group such as styrene and 4- (1-hydroxy-1-methylhexyl) styrene.

  In the styrene-acrylic resin, various monomers capable of vinyl polymerization can be used in combination as required. Such monomers include ethylene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; unsaturated polyenes such as butadiene and isoprene; halogenated compounds such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride. Vinyls; vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether: vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone; vinyl naphthalenes; and maleic acid, citraconic acid, itaconic acid, al Unsaturated dibasic acids such as succinic acid, fumaric acid, mesaconic acid; unsaturated dibasic acid anhydrides such as maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride; methyl half maleate Esters, ethyl maleate half ester, butyl maleate half ester, citraconic acid methyl half ester, citraconic acid ethyl half ester, citraconic acid butyl half ester, itaconic acid methyl half ester, alkenyl succinic acid methyl half ester, fumarate methyl half ester Unsaturated basic acid esters such as mesaconic acid methyl half ester; Unsaturated basic acid esters such as dimethylmaleic acid and dimethylfumaric acid; α, β-unsaturated such as acrylic acid, methacrylic acid, crotonic acid and cinnamic acid Acid acid Water anhydrides; anhydrides of the α, β-unsaturated acids and lower fatty acids; and monomers having a carboxyl group such as alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid, acid anhydrides and monoesters thereof. It is done.

  The styrene-acrylic resin may be a polymer cross-linked with a cross-linkable monomer as exemplified below if necessary. Crosslinkable monomers include, for example, aromatic divinyl compounds, diacrylate compounds linked by alkyl chains, diacrylate compounds linked by alkyl chains containing ether bonds, and chains containing aromatic groups and ether bonds. And diacrylate compounds, polyester-type diacrylates, and polyfunctional crosslinking agents.

Examples of the aromatic divinyl compound include divinylbenzene and divinylnaphthalene.
Examples of diacrylate compounds linked by an alkyl chain include ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6- Examples include hexanediol diacrylate, neopentyl glycol diacrylate, and those obtained by replacing the acrylate of the above compound with methacrylate.

  Examples of diacrylate compounds linked by an alkyl chain containing an ether bond include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, and dipropylene. Examples include glycol diacrylate and those obtained by replacing acrylate of the above compound with methacrylate.

  Examples of diacrylate compounds linked by a chain containing an aromatic group and an ether bond include polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4)- Examples include 2,2-bis (4-hydroxyphenyl) propane diacrylate, and those obtained by replacing the acrylate of the above compound with methacrylate.

  Examples of polyester diacrylates include trade name MANDA (Nippon Kayaku).

  Examples of the polyfunctional crosslinking agent include pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and those obtained by replacing the acrylate of the above compounds with methacrylate; And allyl cyanurate and triallyl trimellitate.

  These crosslinkable monomers can be used in an amount of 0.01 to 10 parts by mass (more preferably 0.03 to 5 parts by mass) with respect to 100 parts by mass of other monomer components. Among these cross-linkable monomers, those which are preferably used from the viewpoint of fixability and offset resistance are aromatic divinyl compounds (particularly divinylbenzene) and divalent groups connected by a chain containing an aromatic group and an ether bond. Examples include acrylate compounds.

  The styrene-acrylic resin may be a resin produced using a polymerization initiator. Examples of such a polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2 , 4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), dimethyl-2,2′-azobisisobutyrate, 1,1′-azobis (1-cyclohexanecarbonitrile), 2-carbamoylazoisobutyronitrile, 2,2′-azobis (2,4,4-trimethylpentane), 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile, 2,2′-azobis ( 2-methylpropane), methylethylketone peroxide, acetylacetone peroxide, ketone peroxide such as cyclohexanone peroxide 2,2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-butyl peroxide, t-Butylcumyl peroxide, dicumyl peroxide, α, α′-bis (t-butylperoxyisopropyl) benzene, isobutyl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5 5-trimethylhexanoyl peroxide, benzoyl peroxide, m-trioyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-2- D Xylethylperoxycarbonate, dimethoxyisopropylperoxydicarbonate, di (3-methyl-3-methoxybutyl) peroxycarbonate, acetylcyclohexylsulfonyl peroxide, t-butylperoxyacetate, t-butylperoxyisobutyrate, t-butylperoxyneodecanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxylaurate, t-butylperoxybenzoate, t-butylperoxyisopropylcarbonate, di-t -Butyl peroxyisophthalate, t-butyl peroxyallyl carbonate, t-amyl peroxy-2-ethyl hexanoate, di-t-butyl peroxy hexahydroterephthalate, di-t-butyl peroxya Rate, and the like.

  The hybrid resin is a resin in which a polyester resin component and a styrene-acrylic resin component are directly or indirectly chemically bonded, and the above-mentioned polyester resin component, styrene-acrylic resin component, and these resin components It is comprised from the monomer component which can react with both.

  Examples of the monomer constituting the polyester resin component that can react with the styrene-acrylic resin component include unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, and itaconic acid, or anhydrides thereof.

  Among the monomers constituting the styrene-acrylic resin component, those capable of reacting with the polyester resin component include those having a carboxyl group or a hydroxyl group, and acrylic acid or methacrylic acid esters.

  As a method for obtaining a hybrid resin, the monomer component capable of reacting with each of the polyester resin and the styrene-acrylic resin listed above is present, and is obtained by polymerizing one or both resins. The method is preferred.

  Examples of the magnetic material used in the magnetic developer include iron oxides such as magnetite, maghemite, and ferrite, and iron oxides including other metal oxides; metals such as Fe, Co, and Ni, or these metals and Al, And alloys with metals such as Co, Cu, Pb, Mg, Ni, Sn, Zn, Sb, Be, Bi, Cd, Ca, Mn, Se, Ti, W, and V; and mixtures thereof.

Conventionally, as a magnetic material, triiron tetroxide (Fe ₃ O ₄ ), iron sesquioxide (γ-Fe ₂ O ₃ ), iron oxide zinc (ZnFe ₂ O ₄ ), iron yttrium oxide (Y ₃ Fe ₅ O _12). ), Iron cadmium oxide (CdFe ₂ O ₄ ), iron gadolinium oxide (Gd ₃ Fe ₅ O ₁₂ ), iron oxide copper (CuFe ₂ O ₄ ), iron oxide lead (PbFe ₁₂ O ₁₉ ), nickel iron oxide (NiFe ₂₎ O ₄ ), neodymium iron oxide (NdFe ₂ O ₃ ), barium oxide (BaFe ₁₂ O ₁₉ ), magnesium iron oxide (MgFe ₂ O ₄ ), manganese iron oxide (MnFe ₂ O ₄ ), iron lanthanum oxide (LaFeO ₃₎ ), Iron powder (Fe), cobalt powder (Co), nickel powder (Ni), etc. are known, but in the present invention, one or more of the above-mentioned magnetic materials may be arbitrarily selected and used. Is possible.

These magnetic materials have an average particle diameter of about 0.1 to 2 μm, and the magnetic characteristics when 795.8 kA / m (10 k Oersted) is applied are such that the coercive force (Hc) is 1.5 kA / m to 12 kA / m, It is preferable that the saturation magnetization (σs) is 50 to 200 Am ² / kg (preferably 50 to 100 Am ² / kg) and the residual magnetization (σr) is ² to 20 Am ² / kg. The magnetic properties of the magnetic material can be measured using a vibration magnetometer such as VSM P-1-10 (manufactured by Toei Kogyo Co., Ltd.) under the conditions of 25 ° C. and an external magnetic field of 769 kA / m.

  In the present invention, the magnetic material can also function as a colorant. From the viewpoint of a colorant, the magnetic material is preferably magnetic iron oxide. Examples of such magnetic iron oxide include fine powders of triiron tetroxide and γ-iron sesquioxide. In addition, the magnetic iron oxide exhibits good magnetism to prevent scattering of the magnetic developer while maintaining fluidity when 20 to 150 parts by mass of the magnetic developer particles are contained in 100 parts by mass of the binder resin. And, it is preferable for expressing sufficient coloring power.

  In the present invention, the magnetic material is appropriately used by using an appropriate surface hydrophobizing agent such as a silane coupling agent or silicone oil according to the intended physical properties of the magnetic developer and the manufacturing conditions of the magnetic developer. The surface may be hydrophobized.

  In the present invention, other additives may be added to the magnetic developer particles as necessary. As such other additives, various additives conventionally known to be added to the inside of magnetic developer particles can be used, and examples thereof include a release agent and a charge control agent.

  Preferred examples of the release agent include aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax; oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax or the like. Block copolymers of these: waxes based on fatty acid esters such as carnauba wax, sazol wax, and montanic acid ester wax; deoxidized part or all of fatty acid esters such as deoxidized carnauba wax Saturated fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid, and parinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvyl alcohol, seryl alcohol Saturated alcohols such as melyl alcohol, polyhydric alcohols such as sorbitol; Fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide; Methylene bis stearic acid amide, ethylene biscapric acid amide, ethylene bis Saturated fatty acid bisamides such as lauric acid amide and hexamethylene bis stearic acid amide; ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid Unsaturated fatty acid amides such as amides; Aromatic bisamides such as m-xylene bis-stearic acid amide and N, N′-distearylisophthalic acid amide; Calcium stearate, calcium laurate, zinc stearate, magnesium stearate, etc. Aliphatic metal salts (generally referred to as metal soaps); waxes grafted with aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid; fatty acids such as behenic acid monoglycerides Examples include partially esterified products of monohydric alcohols; methyl ester compounds having a hydroxyl group obtained by hydrogenation of vegetable oils and fats; long-chain alkyl alcohols or long-chain alkyl carboxylic acids having 12 or more carbon atoms; and the like.

  Examples of the release agent particularly preferably used in the present invention include aliphatic hydrocarbon waxes. As such an aliphatic hydrocarbon wax, for example, a low molecular weight alkylene polymer obtained by radical polymerization of alkylene at a high pressure or a Ziegler catalyst under a low pressure; a high molecular weight alkylene polymer is thermally decomposed. The resulting alkylene polymer; a synthetic hydrocarbon wax obtained from the distillation residue of hydrocarbons obtained from the synthesis gas containing carbon monoxide and hydrogen by the age method; and a synthetic hydrocarbon wax obtained by hydrogenating it; these fats Group hydrocarbon waxes are classified by press sweating, solvent method, vacuum distillation and fractional crystallization.

  Examples of the hydrocarbon as the matrix of the aliphatic hydrocarbon wax include those synthesized by the reaction of carbon monoxide and hydrogen using a metal oxide catalyst (often a multi-component system of two or more types) (for example, Hydrocarbon compounds synthesized by the Gintor method and Hydrocol method (using a fluidized catalyst bed); Up to a few hundred carbon atoms obtained by the Age method (using an identified catalyst bed) in which many waxy hydrocarbons can be obtained A hydrocarbon obtained by polymerizing an alkylene such as ethylene with a Ziegler catalyst. Among such hydrocarbons, in the present invention, it is preferable that the hydrocarbon is a linear hydrocarbon having a small number of branches and a long saturation, and a hydrocarbon synthesized by a method not based on polymerization of alkylene has a molecular weight. Also preferred from the distribution.

  In the present invention, the release agent is a magnetic developer such that when the magnetic developer particles containing the release agent are measured with a differential scanning calorimeter, an endothermic main peak appears in the region of 70 to 140 ° C. in the obtained DSC curve. It is preferable to be contained in the agent particles from the viewpoint of the low temperature fixability and high temperature offset resistance of the magnetic developer.

The temperature at which the endothermic main peak appears can be measured according to ASTM D3418-82 using a highly accurate internal heat input compensation type differential scanning calorimeter, for example, DSC-7 manufactured by PerkinElmer. The temperature at which the endothermic main peak appears can be adjusted by using a release agent in which the melting point, glass transition point, polymerization degree, and the like are appropriately adjusted. In addition to the temperature at which the endothermic main peak appears, the DSC-7 uses the heat of the magnetic developer particles and their materials, such as the glass transition point, softening point, and melting point of the release agent of the binder resin for magnetic developer. It can be applied to the measurement of temperature that shows physical properties.
The release agent preferably contains 2 to 15 parts by mass per 100 parts by mass of the binder resin for magnetic developer in the magnetic developer particles from the viewpoint of fixability and charging characteristics.

  In the magnetic developer used in the present invention, a charge control agent can be used in order to stabilize the chargeability as long as the effects of the present invention are not impaired. The charge control agent varies depending on the type of the charge control agent and the physical properties of other constituent materials of the magnetic developer particles, but generally 0.1 per 100 parts by mass of the binder resin for magnetic developer in the magnetic developer particles. It is preferable that 10-10 mass parts is contained, and it is more preferable that 0.1-5 mass parts is contained.

  As the charge control agent, those that control the magnetic developer to be negatively charged and those that are controlled to be positively charged are known, and are selected from various types depending on the type and use of the magnetic developer. 1 type, or 2 or more types can be used.

  For controlling the magnetic developer to be negatively charged, for example, an organometallic complex and a chelate compound are effective. Examples thereof include a monoazo metal complex; an acetylacetone metal complex; a metal of an aromatic hydroxycarboxylic acid or an aromatic dicarboxylic acid. A complex or a metal salt. Other examples of controlling the negative developer of the magnetic developer include, for example, aromatic mono- and polycarboxylic acids and metal salts and anhydrides thereof; phenol derivatives such as esters and bisphenols; and monomers containing sulfonic acid groups And sulfur-containing resin as a component.

  Examples of controlling the magnetic developer to be positively charged include, for example, modified products of nigrosine and fatty acid metal salts, and the like; tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate and the like. Onium salts such as quaternary ammonium salts and analogs thereof, such as phosphonium salts, and lake pigments thereof; triphenylmethane dyes and lake pigments thereof (phosphorungstic acid, phosphomolybdic acid, phosphotungsten molybdenum are used as lakeing agents) Acid, tannic acid, lauric acid, gallic acid, ferricyanic acid, ferrocyanic compound, etc.); metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; DOO, dioctyl tin borate, diorgano tin borate such as dicyclohexyl tin borate; and the like. In the present invention, these can be used alone or in combination. Among them, a charge control agent such as a nigrosine compound or a quaternary ammonium salt is particularly preferably used for controlling the magnetic developer to be positively charged.

  The magnetic developer used in the present invention can be used by externally adding various materials according to the type of magnetic developer to the magnetic developer particles described above. Examples of the externally added material include a fluidity improver that improves the fluidity of the magnetic developer, such as inorganic fine powder, and a magnetic developer that adjusts the chargeability of the magnetic developer, such as metal oxide fine particles. External additives such as conductive fine powders can be mentioned.

  As the fluidity improver, one that can improve the fluidity of the magnetic developer by externally adding to the magnetic developer particles is used. Examples of such fluidity improvers include fluorine resin powders such as fine vinylidene fluoride powder and polytetrafluoroethylene fine powder; fine powder silica such as wet process silica and dry process silica, fine powder titanium oxide, and fine powder. Alumina; treated silica, surface treated with silane coupling agent, titanium coupling agent, silicone oil, etc., treated titanium oxide, treated alumina; and the like.

The fluidity improver preferably has a specific surface area by nitrogen adsorption measured by the BET method of 30 m ² / g or more, and more preferably 50 m ² / g or more. Although a fluidity improver changes with kinds of fluidity improver, it is preferable to mix | blend 0.01-8 mass parts with respect to 100 mass parts of magnetic developer particles, for example, and mix | blend 0.1-4 mass parts. More preferably.

  The magnetic developer used in the present invention is not particularly limited with respect to the production method thereof, but the above-described binder resin for magnetic developer and magnetic substance, and other additives that are further added as necessary, a Henschel mixer, Mix thoroughly with a mixer such as a ball mill, melt, knead and knead using a heat kneader such as a kneader or extruder to make the resins compatible with each other, cool and solidify the resulting melt-kneaded product, Thereafter, the solidified product is pulverized, and the pulverized product is classified to obtain magnetic developer particles. The magnetic developer particles and external additives such as a fluidity improver are sufficiently mixed as necessary with a mixer such as a Henschel mixer. It can be obtained by mixing.

  In the production of the magnetic developer, the classification can be performed at any time after the magnetic developer particles are generated. For example, the classification may be performed after mixing with the external additive. Further, an appropriate impact such as mechanical or thermal may be applied to the generated magnetic developer particles, and the particle shape of the magnetic developer particles may be controlled (more specifically, spherical).

  In the production of the magnetic developer, a method of applying a mechanical impact force is preferable as a method of pulverizing the solidified product. Examples of the treatment that gives mechanical impact force include a method using a mechanical pulverizer such as a pulverizer KTM manufactured by Kawasaki Heavy Industries, Ltd., a turbo mill manufactured by Turbo Industry Co., Ltd., a mechano-fusion system manufactured by Hosokawa Micron, and Nara Machinery Co., Ltd. The method of processing with apparatuses, such as a manufactured hybridization system, is mentioned. These apparatuses can be used as they are or after being appropriately improved.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

[Developer production example]
(Developer Production Example 1)
Hybrid resin 100 parts by mass (bisphenol A propylene oxide adduct, bisphenol A ethylene oxide adduct, terephthalic acid, succinic acid derivative, trimellitic acid, styrene, 2-ethylhexyl acrylate, acrylic acid; glass transition temperature: 58 ° C., softening Point: 130 ° C., acid value: 12 mgKOH / g)
90 parts by mass of magnetic iron oxide (average particle size: 0.18 μm, Hc: 9.6 kA / m, σs: 81 Am ² / kg, σr: 13 Am ² / kg)
Sulfur-containing resin 5 parts by weight Polyethylene wax (melting point 105 ° C.) 5 parts by weight The above mixture is melt-kneaded with a biaxial extruder heated to 130 ° C., the melt-kneaded mixture is cooled, and the cooled mixture is cooled with a hammer mill. Coarsely pulverized. The coarsely pulverized product was finely pulverized with a turbo mill (manufactured by Turbo Kogyo Co., Ltd.), and the obtained finely pulverized product was classified with an air classifier to obtain a classified product (medium powder) having a weight average particle diameter of 7.8 μm.

To 100 parts by mass of this classified product, 1.0 part by mass of hydrophobic silica fine powder (BET 180 m ^{2 /} g) is externally added with a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.). Thus, Developer Production Example 1 was obtained.

  When the circularity of Developer Production Example 1 was measured using FPIA-1000 (manufactured by Toa Medical Electronics Co., Ltd.), Developer Production Example 1 was a particle having a circle equivalent diameter of 3 μm or more and a circularity of 0.900 or more. Is 94.7% in terms of number-based cumulative value and 71.3% in terms of number-based cumulative number of particles having a circularity of 0.950 or more. The calculated value on the right side of equation (4) is 65.7%. Met. The cut rate Z at this time was 17.8%.

(Developer Production Example 2)
100 parts by mass of polyester resin (bisphenol A propylene oxide adduct, bisphenol A ethylene oxide adduct, terephthalic acid, succinic acid derivative, trimellitic acid condensation polymer, glass transition temperature: 60 ° C., softening point: 140 ° C., acid value : 18mgKOH / g)
90 parts by mass of magnetic iron oxide (average particle size: 0.18 μm, Hc: 9.6 kA / m, σs: 81 Am ² / kg, σr: 13 Am ² / kg)
Azo-based iron complex compound 2 parts by mass Polyethylene wax (melting point 105 ° C.) 5 parts by mass The above mixture was melt kneaded, coarsely pulverized, finely pulverized and classified in the same manner as in Developer Production Example 1, and the weight average particle size 7 A 1 μm classified product (medium powder) was obtained.

To 100 parts by mass of this classified product, 1.0 part by mass of hydrophobic silica fine powder (BET 180 m ^{2 /} g) is externally added with a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.). Thus, Developer Production Example 2 was obtained.

  When the circularity of Developer Production Example 1 was measured using FPIA-1000 (manufactured by Toa Medical Electronics Co., Ltd.), Developer Production Example 1 was a particle having a circle equivalent diameter of 3 μm or more and a circularity of 0.900 or more. Is 92.2% in terms of number-based cumulative value and 73.2% in terms of number-based cumulative number of particles having a circularity of 0.950 or more. The calculated value on the right side of equation (4) is 69.8%. Met. The cut rate Z at this time was 15.7%.

[Example of coating for developer carrier]
(Development carrier coating example C1)
Conductive carbon black 20 parts by mass Graphite having a volume average particle diameter Dv = 5.4 μm (coefficient of variation A = 75.5%)
80 parts by mass Phenol resin solution produced using ammonia as a catalyst (containing 50% methanol)
200 parts by mass Methanol 100 parts by mass The above materials were put into a predetermined container and pre-dispersed with a three-one motor to prepare a dispersion liquid. Next, the rotation speed of the first processing ring shown in FIG. 10 and FIG. 11 is set to 5000 rpm, and 200 kPa of compressed air is introduced into the air introduction part 344, and the surface between the first processing ring 310 and the second processing ring 320. The pressure was adjusted. The dispersion liquid was introduced into the disperser through the introduction unit 322 by the supply mechanism P at a flow rate of 400 ml / hr. The introduced liquid to be dispersed was subjected to strong shear generated between the first processing surface 1 and the second processing surface, and then was discharged into the internal space 330 and discharged from the discharge unit 332 to the outside of the apparatus.

  The paint intermediate C1 had a sharp particle size distribution with a volume average particle diameter Dv = 3.5 μm and a coefficient of variation A = 67.5%.

  As conductive spherical particles, a coal-based bulk mesophase pitch powder 14 having a volume average particle size of 2 μm or less is used on 100 parts by mass of spherical phenol resin particles having a volume average particle size of 6.5 μm using a lykai machine (automatic mortar, manufactured by Ishikawa Kogyo). The mass average particle diameter Dv = 3.7 μm obtained by uniformly coating a mass part, graphitizing by heat-stabilizing at 280 ° C. in air and then firing at 2000 ° C. in a nitrogen atmosphere and further classification. Spherical conductive carbon particles having a coefficient of variation of 43.4%) were used.

Paint intermediate C1 (solid content 50%) 400 parts by mass Phenol resin solution produced using ammonia as a catalyst (containing 50% methanol)
300 parts by mass Quaternary ammonium salt compound (1) 25 parts by mass Spherical conductive carbon particles having a volume average particle diameter Dv = 3.7 μm (variation coefficient: 43.4%)
25 parts by mass Methanol 50 parts by mass Disperse the above materials with zirconia particles of φ2 mm for 3 hours, then separate the zirconia particles with a sieve, adjust the solid content to 40% with methanol, and apply coating solution C1 (c (carbon ) / GF (graphite) / B (binder resin) / P (quaternary ammonium salt compound) / R (spherical particle) = 0.2 / 0.8 / 2.5 / 0.25 / 0.25) Obtained.

  The coating liquid C1 had a volume average particle diameter Dv = 3.7 μm and a coefficient of variation A = 67.3%.

  Further, when the volume resistance of this coating liquid C1 was measured by the method described above, it was 1.16 Ω · cm.

(Development carrier coating example C2)
Dispersion was carried out in the same manner as paint intermediate C1, except that graphite having a volume average particle diameter Dv = 3.2 μm (variation coefficient A = 80.2%) was used, to obtain paint intermediate C2. This paint intermediate C2 had a sharp particle size distribution with a volume average particle diameter Dv = 2.1 μm and a coefficient of variation A = 69.2%.

  As the conductive spherical particles, spherical conductive carbon particles having a volume average particle diameter Dv = 2.5 μm (variation coefficient 45.3%) are used, and the developer carrier is produced in the same manner as in the developer carrier paint production example C1. Manufactured.

Paint intermediate C2 (solid content 50%) 400 parts by weight Quaternary ammonium salt compound (2) 10 parts by weight Spherical conductive carbon particles having a volume average particle diameter Dv = 2.5 μm (variation coefficient 45.3%)
10 parts by mass Methanol 20 parts by mass The above materials were dispersed and adjusted in the same manner as in Production Example C1 for Developer Carriers, and coating liquid C2 (c (carbon) / GF (graphite) / B (binder resin) / P (quaternary ammonium salt compound) / R (spherical particle) = 0.2 / 0.8 / 1.0 / 0.1 / 0.1) was obtained.

  This coating liquid C2 had a volume average particle diameter Dv = 2.3 μm and a coefficient of variation A = 70.1%.

  Further, when the volume resistance of this coating liquid C2 was measured by the above-mentioned method, it was 0.34 Ω · cm.

(Developer carrying body paint production example C3)
Dispersion was performed in the same manner as paint intermediate C1 except that graphite having a volume average particle diameter Dv = 7.7 μm (variation coefficient A = 73.4%) was used, to obtain paint intermediate C3. This paint intermediate C3 had a sharp particle size distribution with a volume average particle diameter Dv = 5.4 μm and a coefficient of variation A = 63.2%.

  As the conductive spherical particles, spherical conductive carbon particles having a volume average particle diameter Dv = 5.6 μm (variation coefficient 39.8%) were used.

Paint intermediate C3 (solid content 50%) 400 parts by mass Phenol resin solution produced using ammonia as a catalyst (containing 50% methanol)
600 parts by mass Quaternary ammonium salt compound (3) 40 parts by mass Spherical conductive carbon particles having a volume average particle diameter Dv = 5.6 μm (variation coefficient 39.8%)
40 parts by weight Methanol 80 parts by weight The above materials were dispersed and adjusted in the same manner as in the developer carrying paint production example C1, and coating liquid C3 (c (carbon) / GF (graphite) / B (binder resin) / P (quaternary ammonium salt compound) / R (spherical particles) = 0.2 / 0.8 / 4.0 / 0.4 / 0.4) was obtained.

  This coating liquid C3 had a volume average particle diameter Dv = 5.6 μm and a coefficient of variation A = 64.4%.

  Further, when the volume resistance of this coating liquid C3 was measured by the method described above, it was 3.46 Ω · cm.

(Development carrier coating example C4)
Conductive carbon black 30 parts by mass Graphite having a volume average particle diameter Dv = 5.4 μm (variation coefficient A = 75.5%)
70 parts by mass Urethane resin solution (containing 50% methanol) 200 parts by mass Methanol 100 parts by mass The above-mentioned materials were used in the developer carrier paint production example C1, the rotation speed of the first treatment ring was 6000 rpm, and the air introduction part 44 was 300 kPa. Dispersion was carried out in the same manner as paint intermediate C1 except that the compressed air was introduced to obtain paint intermediate C4. This paint intermediate C4 had a sharp particle size distribution with a volume average particle diameter Dv = 3.9 μm and a coefficient of variation A = 66.4%.

Paint intermediate C4 (solid content 50%) 400 parts by weight Urethane resin solution (containing 50% methanol) 100 parts by weight Quaternary ammonium salt compound (1) 15 parts by weight Volume average particle diameter Dv = 4.3 μm (coefficient of variation 46. 0%) spherical PMMA particles
10 parts by mass Methanol 25 parts by mass The above materials were dispersed and adjusted in the same manner as in the developer carrier coating production example C1, and coating liquid C4 (c (carbon) / GF (graphite) / B (binder resin) / P (quaternary ammonium salt compound) / R (spherical particles) = 0.3 / 0.7 / 1.5 / 0.15 / 0.1) was obtained.

  This coating liquid C4 had a volume average particle diameter Dv = 4.2 μm and a coefficient of variation A = 67.1%.

  Further, when the volume resistance of this coating liquid C4 was measured by the method described above, it was 1.95 Ω · cm.

(Development carrier coating example C5)
Conductive carbon black 40 parts by mass Graphite having a volume average particle diameter Dv = 5.4 μm (coefficient of variation A = 75.5%)
60 parts by mass Polyamide resin solution (contains 75% methanol) 400 parts by mass Methanol 300 parts by mass The above-mentioned materials are used in the developer carrier coating production example C1, the rotation speed of the first treatment ring is 8000 rpm, and the air introduction part 44 is 400 kPa. Dispersion was carried out in the same manner as paint intermediate C1 except that the compressed air was introduced to obtain paint intermediate C5. This coating material intermediate C5 had a volume average particle diameter Dv = 4.1 μm and a coefficient of variation A = 67.1%.

Paint intermediate C5 (solid content 25%) 800 parts by weight Polyamide resin solution (containing 75% methanol) 200 parts by weight Quaternary ammonium salt compound (1) 15 parts by weight Volume average particle diameter Dv = 4.5 μm (coefficient of variation 49. 2%) spherical silicone resin particles
10 parts by weight Methanol 75 parts by weight The above materials were dispersed and adjusted in the same manner as in the developer carrying body coating production example C1, and coating liquid C5 (c (carbon) / GF (graphite) / B (binder resin) / P (quaternary ammonium salt compound) / R (spherical particle) = 0.4 / 0.6 / 1.5 / 0.15 / 0.1) was obtained.

  This coating liquid C5 had a volume average particle diameter Dv = 4.4 μm and a coefficient of variation A = 68.3%.

  Further, when the volume resistance of this coating liquid C5 was measured by the method described above, it was 1.71 Ω · cm.

(Developer carrying member paint production example C6)
As a raw material for graphitized particles, β-resin is extracted from coal tar pitch by solvent fractionation, and after heavy treatment by hydrogenation, bulk soluble mesophase is removed by removing the solvent soluble component with toluene. Got the pitch. This bulk mesophase pitch is finely pulverized and oxidized in air at about 300 ° C., followed by primary firing at 1200 ° C. in a nitrogen atmosphere and carbonization, followed by carbonization at 3000 ° C. in a nitrogen atmosphere. Graphitized by subsequent firing, and further classified to obtain graphitized particles having a volume average particle diameter Dv = 3.9 μm (variation coefficient 50.2%).

Conductive carbon black 10 parts by mass Graphitized particles having a volume average particle diameter Dv = 3.9 μm (coefficient of variation: 84.1%)
90 parts by mass Phenol resin solution produced using ammonia as a catalyst (containing 50% methanol)
200 parts by weight Methanol 100 parts by weight The above materials were coated with the above intermediate material except that the rotation speed of the first processing ring was 3000 rpm and 100 kPa of compressed air was introduced into the air introduction part 44 in the developer carrier paint production example C1. Dispersion was carried out in the same manner as for C1, to obtain paint intermediate C6. This paint intermediate C6 had a volume average particle diameter Dv = 2.7 μm, a coefficient of variation A = 76.3%, and a sharp particle size distribution.

Paint intermediate C6 (solid content 50%) 400 parts by weight Quaternary ammonium salt compound (1) 10 parts by weight Methanol 10 parts by weight The above materials are mixed with a three-one motor, and coating liquid C6 (c (carbon) / GF (graphite) ) / B (binder resin) / P (quaternary ammonium salt compound) / R (spherical particles) = 0.1 / 0.9 / 1.0 / 0.1 / 0).

  Since this coating liquid C6 is in a state where the quaternary ammonium salt compound (1) is completely dissolved together with methanol in the coating intermediate C6, the volume average particle size and the coefficient of variation are the same as those of the coating intermediate C5.

  Further, when the volume resistance of this coating liquid C5 was measured by the method described above, it was 0.66 Ω · cm.

(Development example C7 for developer carrier)
Dispersion was carried out in the same manner as paint intermediate C6, except that graphitized particles having a volume average particle diameter Dv = 6.3 μm (variation coefficient 82.3%) were used, to obtain paint intermediate C7. This paint intermediate C7 had a sharp particle size distribution with a volume average particle diameter Dv = 4.2 μm and a coefficient of variation A = 71.5%.

Paint intermediate C7 (solid content 50%) 400 parts by mass Phenol resin solution produced using ammonia as a catalyst (containing 50% methanol)
100 parts by mass Quaternary ammonium salt compound (1) 15 parts by mass Methanol 15 parts by mass The above materials are mixed with a three-one motor, and coating liquid C7 (c (carbon) / GF (graphite) / B (binder resin) / P (Quaternary ammonium salt compound) / R (spherical particle) = 0.1 / 0.9 / 1.5 / 0.15 / 0) was obtained.

  Since this coating liquid C7 is a state in which the quaternary ammonium salt compound (1) is completely dissolved together with methanol in the coating intermediate C7, the volume average particle size and coefficient of variation are the same as those of the coating intermediate C7.

  Further, when the volume resistance of this coating liquid C7 was measured by the method described above, it was 0.79 Ω · cm.

(Comparative developer-carrying paint production example c)
In the developer carrying coating production example C1, 25 parts by mass of spherical carbon particles having a volume average particle diameter Dv = 3.7 μm (variation coefficient 43.4%) are used, and a volume average particle diameter Dv = 10.4 μm (variation coefficient 48). .2%) of the spherical carbon particles, except that it was replaced with 10 parts by mass of the spherical carbon particles. The comparative coating solution c (c (carbon) / GF (graphite) / B (binding) Resin) / P (quaternary ammonium salt compound) / R (spherical particles) = 0.2 / 0.8 / 2.5 / 0.25 / 0.1).

  This comparative coating liquid c had a volume average particle diameter Dv = 5.8 μm and a coefficient of variation A = 84.1%. The particle size distribution was broader than that of the coating liquid C1, and the volume average particle diameter Dv was larger.

  Further, when the volume resistance of this comparative coating solution c was measured by the method described above, it was 1.23 Ω · cm.

(Development carrier coating production example S1)
The material of the coating material intermediate C1 of the coating material production example C1 for developer carrying member was subjected to sand mill dispersion with zirconia particles having a diameter of 2 mm for 3 hours, and then the zirconia particles were separated by sieving. This paint intermediate S1 had a volume average particle diameter Dv = 3.3 μm, a coefficient of variation A = 72.1%, and the particle size distribution was slightly broader than that of the paint intermediate C1.

  The coating liquid S1 (c (carbon) / GF (graphite) / B) was prepared in the same formulation, material, and operation except that the coating intermediate C1 was replaced with the coating intermediate S1 in the developer carrying coating production example C1. (Binder resin) / P (quaternary ammonium salt compound) / R (spherical particle) = 0.2 / 0.8 / 2.5 / 0.25 / 0.25) was obtained.

  This coating liquid S1 was a little broader than the coating liquid C1, which differed only in the paint intermediate dispersion method, with a volume average particle diameter Dv = 3.7 μm and a variation coefficient A = 75.3%.

  Further, when the volume resistance of this coating solution S1 was measured by the method described above, it was 1.72 Ω · cm.

(Development carrier coating production example S2)
A coating material intermediate was obtained by the same operation as in the coating material manufacturing example S1 for the developer carrying member using the material of the coating material intermediate C2 of the coating material manufacturing example C2 for the developer carrying member. This paint intermediate S2 had a volume average particle diameter Dv = 1.9 μm, a coefficient of variation A = 77.3%, and the particle size distribution was slightly broader than that of the paint intermediate C2.

  The coating liquid S2 (c (carbon) / GF (graphite) / B) was prepared in the same formulation, material, and operation except that the coating material intermediate C2 was replaced with the coating material intermediate S2 in the coating material production example C2 for developer carrier. (Binder resin) / P (quaternary ammonium salt compound) / R (spherical particle) = 0.2 / 0.8 / 1.0 / 0.1 / 0.1) was obtained.

  This coating liquid S2 was slightly broader than the coating liquid C2, which differed only in the paint intermediate dispersion method, with a volume average particle diameter Dv = 2.3 μm and a variation coefficient A = 73.5%.

  Further, when the volume resistance of this coating solution S2 was measured by the method described above, it was 0.99 Ω · cm.

(Development carrier coating production example S3)
A coating material intermediate was obtained from the material of the coating material intermediate C3 of the coating material production example C3 for the developer carrying member in the same manner as in the coating material production example S1 for the developer carrying material. This paint intermediate S3 had a volume average particle diameter Dv = 5.1 μm, a coefficient of variation A = 70.2%, and the particle size distribution was slightly broader than that of the paint intermediate C3.

  The coating liquid S3 (c (carbon) / GF (graphite) / B) was prepared in the same formulation, material and operation except that the coating intermediate C3 was replaced with the coating intermediate S3 in the coating material production example C3 for developer carrying member. (Binder resin) / P (quaternary ammonium salt compound) / R (spherical particle) = 0.2 / 0.8 / 4 / 0.4 / 0.4) was obtained.

  This coating liquid S3 was a little broader than the coating liquid C3 which differed only in the paint intermediate dispersion method, with a volume average particle diameter Dv = 5.6 μm and a variation coefficient A = 78.9%.

  Further, when the volume resistance of this coating solution S3 was measured by the above-mentioned method, it was 4.01 Ω · cm.

(Development carrier coating production example S4)
The coating material intermediate C4 of the coating material production example C4 for the developer carrying member was obtained in the same manner as in the coating material production example S1 for the developer carrying material, to obtain a coating material intermediate. This paint intermediate S4 had a volume average particle diameter Dv = 3.7 μm, a coefficient of variation A = 73.2%, and the particle size distribution was slightly broader than that of the paint intermediate C4.

  The coating liquid S4 (c (carbon) / GF (graphite) / B) was prepared in the same formulation, material, and operation except that the coating intermediate C4 was replaced with the coating intermediate S4 in the developer carrier coating production example C4. (Binder resin) / P (quaternary ammonium salt compound) / R (spherical particle) = 0.3 / 0.7 / 1.5 / 0.15 / 0.1) was obtained.

  This coating liquid S4 was slightly broader than the coating liquid C4, which was different only in the paint intermediate dispersion method, with a volume average particle diameter Dv = 4.2 μm and a variation coefficient A = 72.8%.

  Further, when the volume resistance of this coating solution S4 was measured by the method described above, it was 2.91 Ω · cm.

(Development carrier coating production example S5)
A coating material intermediate was obtained by the same operation as in the coating material manufacturing example S1 for the developer carrying member using the material of the coating material intermediate C5 of the coating material manufacturing example C5 for the developer carrying member. This paint intermediate S5 had a volume average particle diameter Dv = 3.6 μm, a coefficient of variation A = 74.1%, and the particle size distribution was slightly broader than that of the paint intermediate C5.

  The coating liquid S5 (c (carbon) / GF (graphite) / B) was prepared in the same formulation, material, and operation except that the coating intermediate C5 was replaced with the coating intermediate S5 in the developer carrying coating production example C5. (Binder resin) / P (quaternary ammonium salt compound) / R (spherical particle) = 0.4 / 0.6 / 1.5 / 0.15 / 0.1) was obtained.

  This coating liquid S5 was a little broader than the coating liquid C5, which differed only in the paint intermediate dispersion method, with a volume average particle diameter Dv = 4.4 μm and a coefficient of variation A = 74.2%.

  Further, when the volume resistance of this coating solution S5 was measured by the method described above, it was 2.69 Ω · cm.

(Development carrier coating material production example S6)
The coating material intermediate C6 of the coating material production example C6 for the developer carrying member was obtained in the same manner as in the coating material production example S1 for the developer carrying material, to obtain a coating material intermediate. This paint intermediate S6 had a volume average particle diameter Dv = 2.5 μm, a coefficient of variation A = 83.2%, and the particle size distribution was slightly broader than that of the paint intermediate C6.

  The coating liquid S6 (c (carbon) / GF (graphite) / B) was prepared with the same formulation, material, and operation except that the coating intermediate C6 was replaced with the coating intermediate S6 in the coating material production example C6 for developer carrying member. (Binder resin) / P (quaternary ammonium salt compound) / R (spherical particle) = 0.1 / 0.9 / 1.0 / 0.1 / 0) was obtained.

  Since this coating liquid S6 is in a state in which the quaternary ammonium salt compound (1) is completely dissolved together with methanol in the coating intermediate S6, the volume average particle size and the coefficient of variation are the same as the coating intermediate S6. It was slightly broader than the coating liquid C6, which was different only in the dispersion method.

  Further, when the volume resistance of this coating solution S6 was measured by the method described above, it was 0.96 Ω · cm.

(Development carrier coating production example S7)
A coating material intermediate was obtained by the same operation as in the coating material manufacturing example S1 for the developer carrying member using the material of the coating material intermediate C7 of the coating material manufacturing example C7 for the developer carrying member. This paint intermediate S7 had a volume average particle diameter Dv = 3.9 μm, a coefficient of variation A = 78.6%, and the particle size distribution was slightly broader than that of the paint intermediate C7.

  The coating liquid S6 (c (carbon) / GF (graphite) / B) was prepared in the same formulation, material, and operation except that the coating material intermediate C7 was replaced with the coating material intermediate S7 in the paint carrying example C7 for developer carrying member. (Binder resin) / P (quaternary ammonium salt compound) / R (spherical particle) = 0.1 / 0.9 / 1.5 / 0.15 / 0) was obtained.

  Since this coating liquid S7 is in a state in which the quaternary ammonium salt compound (1) is completely dissolved in the paint intermediate S7 together with methanol, the volume average particle size and coefficient of variation are the same as those of the paint intermediate S7. It was slightly broader than the coating liquid C7, which was different only in the dispersion method.

  Further, when the volume resistance of this coating solution S7 was measured by the method described above, it was 1.20 Ω · cm.

(Comparative developer carrying paint production example s)
In Production Example S1 for Developer Carrier, 25 parts by mass of spherical carbon particles having a volume average particle diameter Dv = 3.7 μm (variation coefficient 43.4%) and volume average particle diameter Dv = 10.4 μm (variation coefficient 48). .2%) of the spherical carbon particles except that 10 parts by mass of the spherical carbon particles was used in the same manner as in the developer carrier coating production example S1, and the comparative coating solution s (c (carbon) / GF (graphite) / B (condensation) Resin) / P (quaternary ammonium salt compound) / R (spherical particles) = 0.2 / 0.8 / 2.5 / 0.25 / 0.1).

  This comparative coating liquid s had a volume average particle diameter Dv = 5.7 μm, a coefficient of variation A = 87.7%, and the particle size distribution was slightly broader than the coating liquid C1, and the volume average particle diameter Dv was larger. .

  Further, when the volume resistance of this comparative coating solution s was measured by the method described above, it was 1.81 Ω · cm.

[Example of developer carrier production]
(Developer carrier production examples C1 to C7)
Spray for atomizing the coating liquids C1 to C7 produced in the developer carrier coating examples C1 to C7 using a swirling air flow discharged from a spiral hole as shown in FIG. By using this method, a 15 μm film was formed on an Al cylinder of φ20 mm, and then heated and cured at 150 ° C./30 minutes with a hot air drier to produce developer carrying body production examples C1 to C7. Ra of the surface of the conductive coating layer on the developer carrying member is surf coder SE-3500 (manufactured by Kosaka Laboratory), with a cutoff of 0.8 mm, an evaluation length of 4 mm, and a feed rate of 0.5 mm / sec. Measurement was performed for 3 points in the axial direction × 3 points in the circumferential direction = 9 points. The results are shown in Table 2. In all cases, Rvk ≦ 1.2 μm and Rpk ≦ 2.0 μm.

(Developer carrier production examples Cb1 to Cb7)
Using a spray gun of a type that blows out air from concentric holes around the nozzle tip, as shown in FIG. 14, with coating liquids C1 to C7 prepared in Paint Production Examples C1 to C7 for Developer Carriers Except for the above, developer carrier production examples Cb1 to Cb7 were produced in the same manner as in developer carrier production examples C1 to C7. Table 2 shows the surface roughness of the conductive coating layer on the developer carrying member. Rpk was Rpk ≦ 2.0 μm, but Rvk was slightly larger than Developer carrying body production examples C1 to C7 by a coating method using a swirling flow, and was 1.2 μm to 1.5 μm.

(Developer carrier production examples S1 to S7)
The coating liquids S1 to S7 produced in the developer carrying body coating production examples S1 to S7 were applied to the developer carrying body production examples S1 to S7 by a coating method using a swirling flow as in the developer carrying body production example C1. S7 was produced. Table 2 shows the surface roughness of the conductive coating layer on the developer carrying member. Both Rvk and Rpk were slightly larger than those using a device that finely disperses through the gaps of the ring-shaped discs shown in FIGS. 10 to 12 as in developer carrier production examples C1 to C7.

(Comparative developer carrier production example 1)
Development was performed except that the coating liquid s produced in the comparative developer carrier coating material production example s was used, as shown in FIG. 14, in which air was blown out from a concentric hole around the nozzle tip. Comparative developer carrier production example 1 was prepared in the same manner as in agent carrier production example C1. Table 2 shows the surface roughness of the conductive coating layer on the developer carrying member. In the coating liquid s, the coating intermediate is a sand mill dispersion, and the difference in volume average particle diameter Dv between the coating intermediate s and the reinforcing particles is large. Moreover, a spray gun as shown in FIG. , Rpk exceeded the preferred range of the present invention.

(Comparative developer carrier production example 2)
Comparative developer carrier production example 2 was produced in the same manner as developer carrier production example C1 using coating liquid c produced in comparative developer carrier paint production example c. Table 2 shows the surface roughness of the conductive coating layer on the developer carrying member. In the coating liquid c, is the coating intermediate used for the coating method using a swirling flow and using a device that finely disperses by passing through the gap of the ring disk shown in FIGS. Rvk was within the preferred range. However, in the coating liquid c, the difference in the volume average particle diameter Dv between the coating intermediate s and the reinforcing particles was large, so that Rpk exceeded the preferable range of the present invention.

(Comparative developer carrier example 3)
The coating liquid S1 produced in the developer carrier paint production example S1 is spray-coated by the same operation as shown in FIG. 14 as in the comparative developer carrier production example 1, and a comparative developer carrier production example 3 Was made. Table 2 shows the surface roughness of the conductive coating layer on the developer carrying member. In the coating liquid S1, the volume average particle size of the coating intermediate S1 and the reinforcing particles is almost the same, but the dispersion of the coating intermediate S1 is a sand mill and a spray gun as shown in FIG. 14 is used. Only Rvk was beyond the preferred range of the present invention.

[Examples A1 to A7]
In the developing apparatus shown in FIG. 1, the developer production example 1 and developer carrier production examples C1 to C7 were used, and the process speed was 230 mm / sec. Normal temperature and low humidity environment (N / L) (temperature 23 ° C, humidity 5%), normal temperature and normal humidity environment (N / N) (temperature 23 ° C, humidity 60%) and high temperature and high humidity environment (H / H) (30 ° C, 80%), 50,000 sheets were each passed through.

  In the paper passing durability by the image forming apparatus using the developing device, a chart having an image ratio of 5% was used for the original. The evaluation results are shown in Table 4-A. The image and developability were evaluated as follows.

(A) Image Density Image density was measured using a Macbeth densitometer (Macbeth Co., Ltd.) using an SPI filter, and a 1.1 mm density 5 mm round reflection density on the original was in the early and middle endurance (when 20,000 images were printed). And after endurance (when 50,000 sheets were printed).

(B) Fog The fog on the image is measured with a reflection densitometer (reflectometer model TC-6DS manufactured by Tokyo Denshoku Co., Ltd.) on the transfer material before image formation and the white background after image formation. The worst value (maximum value) of partial reflection density was Ds (%), the average reflection density of the transfer material before image formation was Dr (%), and (Ds)-(Dr) was determined and evaluated as the fog amount. The measurement was performed at the initial stage of durability, the middle period of durability, and after the durability, and fog was evaluated according to the following criteria.
A: Fog amount is 1.0% or less B: Fog amount is 1.0-2.0% or less C: Fog amount is 2.0-3.0% or less D: Fog amount is 3.0-4.0 % Or less (practical level lower limit)
E: The fog amount exceeds 4.0% (impractical level)

(C) Sleeve ghost After the end of durability, the end of durability, and after endurance, the position of the developer carrying member that developed an image in which the solid white portion and the solid black portion are adjacent to each other comes to the developing position at the next rotation of the developer carrying member, and halftone The image was developed, and the difference in density appearing on the halftone image thus formed was visually observed and evaluated according to the following criteria.
A: No shade difference is observed at all. B: A slight shade difference can be confirmed depending on the viewing angle. C: A shade difference where the edge is not clear can be confirmed, but it is practically OK level.
D: Difference in shading is slightly clear (practical level lower limit)
E: The density difference can be clearly confirmed, and it can be confirmed as the image density difference (impractical level)

(D) Blotch (defective image)
Visual observation of various images such as solid black, halftone, and line images, and at that time, magnetic developer coating defects on the developer carrier such as wavy irregularities and blotches (spotted irregularities) on the developer carrier Referring to, the observation results in the initial durability period, the intermediate durability period, and after the durability period were evaluated based on the following criteria.
A: Neither image nor sleeve can be confirmed at all.
B: Although it can be confirmed slightly on the sleeve, it can hardly be confirmed on the image.
C: The first halftone image or solid black image can be confirmed on the first cycle of the sleeve cycle.
D: Can be confirmed with a halftone image or a solid black image (practical level lower limit)
E: An image defect that causes a practical problem in the entire solid black image can be confirmed (impractical level).

(E) Sleeve contamination and fusion with magnetic developer (contamination and anti-fusing)
After image evaluation under each environment, the developing sleeve was removed, the magnetic developer on the surface of the developing sleeve was removed with a vacuum cleaner and air blow (by air gun), and an ultra-deep shape measuring microscope (manufactured by KEYENCE, Inc .: VK-8500) ), And with reference to this, the evaluation results are shown by the following indices.
A: There is no magnetic developer at all.
B: A fine powder of magnetic developer is slightly observed in the dent on the sleeve surface.
C: Magnetic developer particles remain in the dents on the sleeve, but the original shape of the magnetic developer particles remains.
D: Magnetic developer particles adhering to the sleeve are present in various places, and the magnetic developer particles are crushed as if they are slightly melted. It does not appear on the image. (Practical level lower limit)
E: The magnetic developer adheres to the sleeve surface. Appears on the image (impractical level)
All were very good results.

[Examples B1 to B7]
In Examples A1 to A7, images and developability were evaluated in the same manner except that Developer Carrier Production Examples Cb1 to Cb7 were used. The evaluation results are shown in Table 4-B. The H / H sleeve contamination / fusion, the N / L fogging and blotch after the 20,000th sheet were slightly inferior to Examples A1 to A7 and ranked B, but they were at no problem level. The others were very good results.

[Examples C1 to C7]
In Examples A1 to A7, images and developability were evaluated in the same manner except that Developer Production Example 2 and Developer Carrier Production Examples S1 to S7 were used. The evaluation results are shown in Table 4-C. H / H sleeve contamination / fusion is the initial B rank, 20,000th and subsequent C ranks, N / L fog and blotch are the 20,000th and Bth ranks, and the 50,000th and subsequent C ranks. Although it was slightly inferior to B1-B7, it was a level which is satisfactory practically. The others were very good results.

[Comparative Example 1]
Image evaluation was performed in the same manner as in Example 1 except that Developer Production Example 1 and Comparative Developer Carrier Production Example 1 were used. The evaluation results are shown in Table 4-D. H / H sleeve contamination / fusion was from 20,000 durability to NG level, so H / H was interrupted at 20,000. Since the Rvk of Comparative Developer Carrier Production Example 1 exceeds 2.0 μm, a large number of deep recesses are formed, and magnetic development is caused by rubbing between the developer regulating member 11 and the rotary stirring member 6 here. The agent accumulated, resulting in sleeve contamination and fusion. Further, since Rpk exceeds 3.0 μm, a lot of sharp peaks are formed, and the magnetic developer is caught in this portion by rubbing against the developer regulating member 11 and the rotary stirring member 6 and accumulated with durability. This resulted in sleeve contamination and fusion.

  In N / L, fog and blotch deterioration were observed in the second half of the endurance due to the same phenomenon.

[Comparative Example 2]
Image evaluation was performed in the same manner as in Example 1 except that Developer Production Example 1 and Comparative Developer Carrier Production Example 2 were used. The evaluation results are shown in Table 4-D. The initial 20,000 sheets of H / H sleeve contamination / fusion were at the practical level, but after 50,000 sheets were at the NG level, the H / H was interrupted at 50,000 sheets. This is because the Rpk of Comparative Developer Carrier Production Example 2 exceeds 3.0 μm, so that a lot of sharp peaks are formed, and the friction between the developer regulating member 11 and the rotary stirring member 6 is also formed in this portion. As a result, the magnetic developer was caught and accumulated along with the durability, resulting in sleeve contamination and fusion. For this reason, the initial to 20,000 sheets were barely at a practical level, but after 50,000 sheets were considered NG.

[Comparative Example 3]
Image evaluation was performed in the same manner as in Example 1 except that Developer Production Example 1 and Comparative Developer Carrier Production Example 3 were used. The evaluation results are shown in Table 4-D. The initial 20,000 sheets of H / H sleeve contamination / fusion were at the practical level, but after 50,000 sheets were at the NG level, the H / H was interrupted at 50,000 sheets. Since the Rvk of Comparative Developer Carrier Production Example 3 exceeds 2.0 μm, a large number of deep recesses are formed, and magnetic development is caused by rubbing between the developer regulating member 11 and the rotary stirring member 6 here. The agent accumulated, resulting in sleeve contamination and fusion. For this reason, the initial to 20,000 sheets were barely at a practical level, but after 50,000 sheets were considered NG.

It is a figure explaining the developing device of this invention. It is a schematic diagram which shows the conductive resin coating layer on the surface of a developer carrier. It is a figure explaining the conventional developing device. It is a measurement model of the triboelectric charge amount by the gradient method. It is a figure which shows the charge amount of a model negative toner with respect to the addition amount to the resin of a quaternary ammonium salt compound. It is a figure for demonstrating the definition of a load length rate (tp) and a load curve (BAC). It is a figure for demonstrating how to obtain | require oil sump depth Rvk. It is a figure for demonstrating how to obtain | require initial wear height Rpk. It is a figure explaining the conventional developing device. It is a partial notch longitudinal cross-sectional view of the dispersion apparatus used for the Example of this invention. It is a principal part schematic sectional drawing of the dispersion apparatus used for the Example of this invention. FIG. 3 is a schematic diagram of a dispersing device part used in the present invention. It is a schematic diagram which shows a needle type air spray gun. It is a schematic diagram which shows the type of spray gun which blows off air from the hole on the concentric circle around the nozzle tip. It is a schematic diagram which shows the type of spray gun which discharges atomization air as a swirl flow from the spiral hole around a nozzle. FIG. 2 is a schematic cross-sectional view of an example mechanical pulverizer used in the toner pulverization step of the present invention. It is a schematic sectional drawing in the D-D 'surface in FIG. It is a perspective view of the rotor shown in FIG. It is explanatory drawing of average line depth Rv. It is explanatory drawing of average line height Rp.

Explanation of symbols

1, 101 ... Developer carrier 2, 102 ... Image carrier 5, 105 ... Hopper chamber 6, 106 ... Rotating stirring member 11, 111 ... Developer regulating member 12, 112 ... Supply developer Openable and closable openings 13, 113... Developer replenishment detecting members 14 and 114... Developer replenishment determining devices 15 and 115... Developer regulating member 103. Partition wall 110 Opening 201 Resin coating layer 202 Reinforcing particles 203 Conductive fine particles 204 Binder resin 205 Solid lubricant 206 Cylindrical substrate 301 First treated surface 302 ... 2nd processing surface 303 ... Case 304 ... Contact surface pressure applying mechanism 305 ... Rotation drive device 310 ... 1st processing ring 311 ... 1st holder 320 ... 2nd processing ring 321 ... 2nd Holder 32 · ··········································································································································································· Outlet portion Fixing tool 412 ... Swirl chamber 419 ... Pipe 420 ... Distributor 422 ... Bag filter 424 ... Suction filter 429 ... Collection cyclone 501 ... Mechanical pulverizer 502 ... Powder discharge port 510 ... Stator 511 ... Powder inlet 512 ... Rotating shaft 513 ... Casing 514 ... Rotor 515 ... First metering feeder 516 ... Jacket 517 ... Cooling water supply port 518 ... Cooling water outlet 520 ... Rear chamber 521... Cold air generating means 531... Third metering feeder

Claims (3)

Magnetic developer,
A developer container having the magnetic developer therein;
A developer carrier that is disposed in the upper opening of the developer container and that is disposed in proximity to or in pressure contact with the image carrier to supply the magnetic developer;
Rotating agitation means for moving the magnetic developer inside the developer container toward the developer carrier;
Replenishment detection means for detecting replenishment of the magnetic developer inside the developer container,
The lower end of the developer carrying member in the developing apparatus is positioned at the top than the central axis of rotation of the rotary stirring means,
The magnetic developer includes magnetic developer particles obtained by pulverizing a solidified product of a melt-kneaded material including a binder resin, a magnetic material, and a release agent by mechanical pulverization and an external additive, and includes a weight average particle. In particles having a diameter of 5 μm to 12 μm and 3 μm or more of the magnetic developer, 90% or more of particles having a circularity a calculated from the following formula (1) of 0.900 or more in terms of the number-based cumulative value. ,
Circularity a = L ₀ / L ------- (1)
[Expression, L ₀ represents the circumference of a circle having the same projected area as the particle image, and L represents the circumference of the particle image. ]
The developer-carrying member has at least a substrate and a resin coating layer on the surface of the substrate, an oil reservoir depth (Rvk) of 2.0 μm or less on the surface of the resin coating layer, and an initial wear height (Rpk). Is a developing device having a thickness of 3.0 μm or less.   The developing device according to claim 1, wherein an upper end of the replenishment detection unit is positioned below a rotation shaft of the stirring unit.   The developing device according to claim 1, wherein a powder surface of the magnetic developer inside the developing container is below a lower end of the developer carrying member.

Images