JP2012013885A - Image forming apparatus and process cartridge - Google Patents

Abstract

The present invention prevents wear and filming of an image carrier, contamination of a charging member, and toner slippage, can maintain its effect over time, can cope with changes in the external environment, and can detect abnormal images. There is provided an image forming apparatus capable of preventing occurrence and obtaining a good quality image stably over a long period of time.
An image forming apparatus of the present invention includes a protective layer forming apparatus 2. The protective layer forming apparatus 2 includes an image carrier protective agent 21 containing at least a fatty acid metal salt and an inorganic lubricant, and the image carrier. A protective agent supply member 22 for applying or adhering a protective agent to the surface of the image carrier 1 is provided, and the image forming apparatus main body is provided with detection means for detecting the temperature and humidity of the external environment. And a control means for executing the image carrier refresh mode during non-image formation based on the detection result of the detection means for detecting the image.
[Selection] Figure 5

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a plotter, a facsimile, or a multifunction machine having these functions, and a printer having the protective layer forming apparatus for forming a protective layer on the surface of the image carrier. The present invention relates to a process cartridge to be used.

  Conventionally, in electrophotographic image formation, a latent image is formed by an electrostatic charge on an image carrier made of a photoconductive substance, and charged colored particles (referred to as toner) are applied to the electrostatic latent image. A visible image is formed by adhering. The visible image formed by the toner is finally transferred to a transfer medium such as paper, and then fixed to the transfer medium by heat, pressure, solvent gas, or the like, and becomes an output image.

  These image forming methods include a so-called two-component development method that uses friction charging by stirring and mixing toner particles and carrier particles by a method of charging toner particles for visualization, and without using carrier particles. In other words, the toner particles are roughly classified into so-called one-component development systems in which charge is imparted to toner particles. In addition, the one-component development method is classified into a magnetic one-component development method and a non-magnetic one-component development method depending on whether or not a magnetic force is used for holding toner particles on the developing roller.

Up to now, in copiers that require high speed and image reproducibility, and multi-function machines based on these, two components are required due to demands such as toner particle charging stability, start-up stability, and long-term image quality stability. One-component development methods have been often employed in small printers, facsimiles, and the like that require many development methods and have great demands for space saving and cost reduction.
In particular, in recent years, colorization of output images has progressed, and the demand for higher image quality and stabilization of image quality has become stronger than ever.
In order to improve the image quality, the average particle diameter of the toner is reduced, and the shape of the particles is not rounded and becomes more round.

  In these electrophotographic image forming apparatuses, a drum-shaped or belt-shaped image carrier (generally a photosensitive member) is uniformly charged while rotating regardless of the development method, and laser light, etc. To form a latent image pattern on the image bearing member, which is visualized by a developing device, and further transferred onto a transfer medium.

Further, the toner component that has not been transferred remains on the image carrier after the toner image is transferred to the transfer medium. When these residues are conveyed to the charging process as they are, it is often the case that the uniform charging of the image carrier is hindered. The components and the like are removed in a cleaning process to make the surface of the image carrier sufficiently clean, and then charging is performed.
As described above, various physical stresses and electrical stresses exist in each image forming process, and the image carrier, the charging member, and the cleaning member deteriorate.

In order to solve this problem, many proposals have been made so far regarding various lubricants and lubricant component supply / film formation methods in order to reduce deterioration of the image carrier, charging member, and cleaning member.
For example, in Patent Document 1 (Japanese Patent Publication No. 51-22380), in order to extend the life of the photoreceptor and the cleaning blade, a solid lubricant mainly composed of zinc stearate is supplied to the photoreceptor surface to lubricate the photoreceptor surface. It has been proposed to form a film. As a result, it is possible to suppress wear on the surface of the photoreceptor and to extend the life of the image carrier.

In Patent Document 2 (Japanese Patent Application Laid-Open No. 2006-350240), various lubricants obtained by adding boron nitride, which is one of inorganic lubricants, to a solid lubricant mainly composed of zinc stearate on the surface of an image carrier are supplied. As a result, even when an electrical stress is applied to the surface of the image carrier due to the charging process, the lubricity is hardly lowered, and a lubricant film is formed over the entire surface of the image carrier to maintain high lubricity. You can do that.
In addition, the toner cleaning property has been dramatically improved, and it is possible to clean toner having a small particle size and high circularity in recent years. Further, the cleaning property has been improved, so that contamination of the charging member is reduced, and the life of the charging member can be extended. Further, since the toner does not slip through, the blade wear is small, and the life of the cleaning blade can be extended.
Further, as disclosed in Patent Document 2, as one of means for realizing a solid lubricant in which an inorganic lubricant or inorganic fine particles are included in a fatty acid metal salt such as zinc stearate, it is solidified into a bar shape by compression molding. A manufacturing method has been proposed.

  In Patent Document 3 (Japanese Patent Laid-Open No. 2001-305907), a lubricant supply device is shown as a specific method for applying a solid lubricant. The lubricant supply device described in Patent Document 3 is in contact with a bar-like solid lubricant, and a fine powdery lubricant scraped off by rubbing the lubricant into a photosensitive belt or an intermediate transfer belt (lubricant). A brush roller (supply member) for supplying to a supply object is provided. The solid lubricant is held by a lubricant holding member, and a spring (biasing means) is in contact with the lubricant holding member. The solid lubricant is pressed against the brush roller by the biasing force of the spring. When the brush roller rotates, the solid lubricant in contact therewith is rubbed, and the lubricant scraped off and attached to the brush roller is applied to the surface of the photosensitive belt or intermediate transfer belt. The lubricant supply device is provided with a lubricant leveling blade. This lubricant leveling blade is for spreading the lubricant applied to the surface of the photoreceptor belt or the intermediate transfer belt to form a lubricant layer having a uniform thickness on the surface.

  However, in the configuration in which the spring contacts and is pressed against the brush roller, the spring expands as the solid lubricant is shaved, and the pressing force inevitably decreases. As a result, the amount of solid lubricant is reduced, and the amount of solid lubricant supplied to the photoreceptor and intermediate transfer belt is also reduced, so that the photoreceptor and intermediate transfer belt cannot be sufficiently protected. .

With respect to these problems, Patent Document 4 (Japanese Patent Application Laid-Open No. 2007-293240) discloses a solid lubricant by providing a movable pressing member on a member that holds the solid lubricant and pressurizing it with a spring member. It is said that the same pressure can be maintained over time.
However, it has been found that a solid lubricant block obtained by compression molding cannot prevent a decrease in consumption over time even if the same pressure is maintained over time.

With respect to this problem, in Patent Document 5 (Japanese Patent Laid-Open No. 2007-65100), the decrease in consumption can be suppressed by making the hardness on the front side larger than the hardness on the back side in the front and back direction of the solid lubricant. Yes.
The stress on the image carrier is received not only from the cleaning process but also from the charging process, and the electrical stress greatly changes the state of the image carrier surface. Further, this electrical stress is conspicuous in the contact charging method and the proximity charging method that involve a discharge phenomenon near the surface of the image carrier. In these charging methods, many active species and reaction products are generated on the surface of the image carrier, and many active species and reaction products generated in the atmosphere in the discharge region are adsorbed on the surface of the image carrier. .

A lubricant using zinc stearate as in Patent Document 1 described above covers the surface of the image carrier relatively evenly and provides good lubricity and protection. Therefore, the use of zinc stearate can be easily solved in order to prevent photoconductor wear, which is a problem in the image forming process in which an alternating voltage is applied when the image carrier is charged.
However, zinc stearate has a big problem in terms of cleaning properties. In a normal image forming process, a blade cleaning system is adopted as a means for removing the residual toner after transfer from the photoreceptor. However, zinc stearate has a property that the toner easily slips through the blade. If the toner slips through the cleaning blade, the toner directly appears on the image or further accelerates the contamination of the charging member. Due to contamination of the charging member, an abnormal image such as density unevenness occurs. The toner slipping becomes more noticeable as the toner becomes spherical with a small particle diameter. In addition, since a material using zinc stearate often slips out of toner or the like, the cleaning blade is worn and the image forming apparatus has a short life. In addition, zinc stearate is susceptible to electrical stress and easily deteriorates. As a result, the lubricity is further lost, and the toner slipping and the charging member contamination are further accelerated.

  In Patent Document 6 (Japanese Patent Laid-Open No. 2005-30201) and Patent Document 7 (Japanese Patent Laid-Open No. 2006-154212), control is performed for the purpose of removing zinc stearate deteriorated in the charging process. In Patent Document 6, various sensors are mounted and controlled for the purpose of removing zinc stearate deteriorated in the charging process. However, mounting many sensors increases the configuration of the image forming apparatus and leads to an increase in cost. Further, Patent Document 7 discloses a filming removal mode for preventing the occurrence of filming in an image forming apparatus having a plurality of image carrier linear velocities. This filming removal mode is a method of reducing the AC charging current superimposed on the DC voltage at the time of execution, inputting the toner to the image carrier, and scraping off the toner together with the cleaning member.

  Further, in Patent Document 2, as described above, an image carrier by the charging process is supplied by supplying an inorganic lubricant added with boron nitride to a solid lubricant mainly composed of zinc stearate on the surface of the image carrier. Even if the surface is subjected to electrical stress, the lubricity is hardly lowered, and a lubricant film can be formed over the entire surface of the image carrier to maintain a high lubricity. However, the protective agent containing boron nitride has a high adhesive force to the image carrier of the inorganic lubricant itself, and a low image area ratio and an image output with many non-image areas are used continuously over time. When paper is used or when it is carried out in a high-temperature and high-humidity environment, a protective agent is deposited on the image carrier and causes filming on the image carrier. As a result, a defective image or image blur due to insufficient charging occurs. However, since the filming substance resulting from this boron nitride has a weak adhesive force, it can be easily removed, unlike the filming that occurs when a protective agent containing only zinc stearate is used.

  The present invention has been made in view of the above-described problems of the prior art, and prevents wear and filming of the image carrier, contamination of the charging member, and toner slip-through. To provide an image forming apparatus that can maintain an effect, can cope with a change in the external environment, can prevent abnormal images from occurring, and can stably obtain a good quality image over a long period of time. With the goal. Another object of the present invention is to provide a process cartridge used in the image forming apparatus.

In order to achieve the above object, the present invention adopts the following means [1] to [14].
[1]: A charging device having an image carrier and a charging member arranged close to or in contact with the image carrier and applying a charging bias voltage to the charging member to uniformly charge the surface of the image carrier An exposure device that exposes the surface of the charged image carrier based on image data and writes a latent image; and a developing device that supplies toner to the latent image formed on the surface of the image carrier to visualize the latent image. A transfer device for transferring a visible image on the surface of the image carrier directly to a transfer medium or via an intermediate transfer member, a cleaning device for cleaning the surface of the image carrier after the transfer, and an image on the surface of the image carrier. An image forming apparatus comprising: a protective layer forming apparatus for applying or adhering a carrier protective agent, wherein the protective layer forming apparatus includes an image carrier protective agent containing at least a fatty acid metal salt and an inorganic lubricant, and the image carrier. A body protecting agent for the image carrier A protective agent supplying member that is applied or adhered to the surface, and the image forming apparatus main body includes a detection unit that detects the temperature and humidity of the external environment, and the detection result of the detection unit that detects the temperature and humidity of the external environment And a control means for executing an image carrier refresh mode during non-image formation based on the above (claim 1).
[2]: In the image forming apparatus according to [1], in the image carrier refresh mode, the image carrier is idled at a predetermined number of rotations regardless of whether the charging member is charged or not. (Claim 2).
[3]: In the image forming apparatus according to [1] or [2], in the image carrier refresh mode, the image carrier and the protective agent supply member are idled at a predetermined number of rotations. (Claim 3).
[4]: In the image forming apparatus according to any one of [1] to [3], the detection unit that detects the temperature and humidity of the external environment includes a temperature sensor attached to the main body of the image forming apparatus. It is a humidity sensor (Claim 4).
[5]: In the image forming apparatus according to any one of [1] to [4], the fatty acid metal salt contained in the image carrier protecting agent is zinc stearate (claim). Item 5).
[6]: In the image forming apparatus according to any one of [1] to [5], the inorganic lubricant contained in the image carrier protecting agent is boron nitride. 6).
[7]: In the image forming apparatus according to any one of [1] to [6], the protective layer forming apparatus includes a protective agent supply member made of a rotating brush-like member. And supplying to the surface of the image carrier via the above (claim 7).
[8] The image forming apparatus according to any one of [1] to [7], further including a layer forming member that presses the image carrier protective agent supplied to the surface of the image carrier to form a film. (Claim 8).
[9]: In the image forming apparatus according to [8], the layer forming member is a blade-like member (claim 9).
[10: The image forming apparatus according to any one of [1] to [9], wherein the image carrier is a photoconductor.
[11]: In the image forming apparatus according to any one of [1] to [10], the circularity SR of the toner is
The circularity SR is 0.93 to 1.00 when the circularity SR = peripheral length of a circle having the same area as the particle projection area / perimeter length of the particle projection image (claim 11). ).
[12]: In the image forming apparatus according to any one of [1] to [11], a ratio (D4 / D1) of the weight average diameter (D4) to the number average diameter (D1) of the toner is 1. It is 00-1.40 (claim 12).
[13]: A process cartridge used in the image forming apparatus according to any one of [1] to [12], wherein at least an image carrier that has undergone a step of carrying a toner image, and the toner image is transferred A protective layer forming device for applying or adhering an image carrier protecting agent to the surface of the image carrier after being transferred to the medium is integrally provided, and is detachably attached to the image forming apparatus main body. (Claim 13).
[14]: The process cartridge according to [13], wherein a charging device, a developing device, and a cleaning device are integrally provided in addition to the image carrier and the protective layer forming device. .

  In the image forming apparatus of the present invention, the protective agent containing a fatty acid zinc salt and an inorganic lubricant used in the protective layer forming apparatus is excellent in lubricity and wears the cleaning member for a long time without passing through the toner cleaning. Can be prevented. Therefore, the image carrier refresh mode can be implemented over a long period of time. Further, since toner does not slip through, the charging member is not contaminated over a long period of time. Further, it is not always necessary to control the AC charging current of the charging member to remove the filming substance, which is much simpler than the conventional method.

More specifically, it is considered that the image forming apparatus of the present invention can suppress filming on the image carrier for the following reason.
An electrophotographic image carrier (for example, a photoreceptor) is coated with an image carrier protective agent to protect the image carrier from charging and cleaning hazards.
However, as a protective agent, the fatty acid metal salt has reduced lubricity due to the effect of charging, and in the cleaning member, toner and protective agent slip through and adhere to the charging member, causing charging member contamination. .
Therefore, by adding an inorganic lubricant, it is possible to assist lubricity, prevent the toner and the protective agent from slipping through, and reduce the amount of fatty acid metal salt flying to the charging member.

At present, a protective agent using a fatty acid metal salt typified by zinc stearate as a main raw material is generally used in many color machines. This protective agent is molded and solidified by melting a fatty acid metal salt as a raw material and pouring it into a mold.
On the other hand, in a protective agent in which an inorganic lubricant is added to a fatty acid metal salt, when the raw material is melted and molded and solidified, it becomes a very hard solid block and can be scraped off with a supply member such as a brush. Therefore, photoconductor contamination occurs. This is considered because the inorganic lubricant plays the role of a filler. Therefore, a protective agent obtained by adding an inorganic lubricant to a fatty acid metal salt is generally produced by compression molding.

The protective agent containing boron nitride has a high adhesive force to the image carrier of the inorganic lubricant itself, and when image formation is performed in a high temperature and high humidity environment, the protective agent is deposited on the image carrier, Filming is generated on the image carrier. As a result, defective images and image blur due to insufficient charging occur.
Therefore, in the present invention, in an image forming apparatus having a protective layer forming apparatus using an image carrier protecting agent containing a fatty acid metal salt and an inorganic lubricant, an image carrier that removes a filming substance on the surface of the image carrier. By having the refresh mode and executing the image carrier refresh mode at a time other than the time of image formation based on the result of the detection means that detects the temperature and humidity of the external environment, it is stable regardless of the external environment over time An image can be output.

In the image forming apparatus of the present invention, since the image carrier surface is rubbed by the supply member by executing the image carrier refresh mode at a predetermined temperature and humidity, filming on the surface of the image carrier is removed. And can output an image stably over time.
However, if the image carrier refresh mode is not executed at a predetermined temperature and humidity, an abnormal image is output, and the image cannot be output stably over time.

In the present invention, better photoconductor protection is obtained when stearic acid is used as the fatty acid metal salt. Of the higher fatty acids, stearic acid is the cheapest, and among them, zinc salts are very stable substances with excellent hydrophobicity.
In the present invention, the use of boron nitride as the inorganic lubricant provides a better effect of preventing charging member contamination.

  In the present invention, the image carrier protecting agent exhibits a protective effect by adhering to the surface of the image carrier and forming a film, and thus is relatively easily plastically deformed. Accordingly, when an attempt is made to form a protective layer by directly pressing the bulky image carrier protective agent component onto the surface of the image carrier, not only the supply becomes excessive and the protective layer formation efficiency is not good, but also the protective layer becomes multilayered and static. Since it may become a factor that impedes light transmission in an exposure process such as when forming an electrostatic latent image, the types of image carrier protecting agents that can be used are limited. On the other hand, the protective layer forming apparatus has a brush-like supply member, and a soft image carrier protective agent is obtained by interposing a brush-like supply member between the image carrier protective agent and the image carrier. Even when used, the protective agent can be evenly supplied to the surface of the image carrier by the brush-like supply member. Further, when the protective layer forming apparatus is provided with a layer forming member that presses the image carrier protective agent to form a film, the layer forming member may also serve as a cleaning member, but in order to form the protective layer more reliably, It is preferable to remove in advance a residue mainly composed of toner on the image carrier with a cleaning member so that the residue does not enter the protective layer.

  In the present invention, by configuring the process cartridge using the protective layer forming apparatus having the image carrier protecting agent, the process cartridge replacement interval can be set to be extremely long, so that the running cost is reduced. In addition, the amount of waste can be greatly reduced.

  In addition, since the component of the image carrier protecting agent of the present invention does not substantially contain a metal component, the charging member disposed in contact or close to the charging member is not contaminated with a metal oxide or the like. The change with time can be reduced. For this reason, it becomes easy to reuse process cartridge components such as an image carrier and a charging member, and the amount of waste can be further reduced.

1 is an overall perspective view of a mold used for producing an image carrier protecting agent of the present invention. It is the schematic sectional drawing which looked at the type | mold shown in FIG. 1 from the longitudinal direction. It is a schematic perspective view which shows an example of the produced image carrier protective agent block. FIG. 4 is a schematic cross-sectional view of an essential part showing an example in which the image carrier protecting agent block shown in FIG. 3 is attached to a holder. FIG. 3 is a schematic configuration diagram illustrating a main part of a configuration example of a main part of an image forming unit of an image forming apparatus including a protective layer forming apparatus according to the present invention. It is a schematic sectional drawing for demonstrating the outline of the structural example of the process cartridge using the protective layer forming apparatus which concerns on this invention. It is a schematic block diagram which shows an example of the image forming apparatus which comprises the protective layer forming apparatus of this invention. 3 is a block diagram illustrating an example of a control system of the image forming apparatus of the present invention. FIG. It is a table | surface which shows the Example of this invention, a comparative example, and an evaluation result.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the image forming apparatus of the present invention, it is essential that the image carrier protecting agent used in the protective layer forming apparatus contains a fatty acid metal salt and an inorganic lubricant. Furthermore, in the image forming apparatus of the present invention, it is essential to execute the image carrier refresh mode.

  Examples of fatty acid metal salts contained in the image carrier protective agent include barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, cadmium stearate , Magnesium stearate, zinc stearate, zinc oleate, magnesium oleate, iron oleate, cobalt oleate, copper oleate, lead oleate, manganese oleate, zinc palmitate, cobalt palmitate, lead palmitate, palmitate Magnesium oxide, aluminum palmitate, calcium palmitate, lead caprylate, lead caprate, zinc linolenate, cobalt linolenate, calcium linolenate, zinc ricinoleate, cadmium ricinoleate Beauty mixtures thereof, but is not limited to this. Moreover, you may mix and use these.

  The inorganic lubricant contained in the image carrier protecting agent refers to a material that cleaves and lubricates itself or causes internal slip. Examples of this include, but are not limited to, mica, boron nitride, molybdenum disulfide, tungsten disulfide, talc, kaolin, montmorillonite, calcium fluoride, and graphite. Boron nitride, for example, has hexagonal mesh surfaces with tightly intermingled atoms and a wide gap between them, and only the weak van der Waals force connects the layers, so that the layers are easily cleaved and lubricated. .

An example of means for realizing the image carrier protecting agent of the present invention will be described below with reference to the drawings.
FIG. 1 is an overall perspective view of a mold used for producing the image carrier protecting agent of the present invention, and FIG. 2 is a schematic sectional view of the mold shown in FIG.
As shown in FIGS. 1 and 2, raw material 1005 before compression is put in a place where the lower mold 1002 is sandwiched between the horizontal mold 1003 and the end mold 1004.
Further, a small amount and the same amount of raw materials are put into both end regions and pressed with the upper mold 1001. As a result, it is possible to produce an image carrier protecting agent block in which the density of the end region is larger than that of the central region.
FIG. 3 is a schematic perspective view showing an example of the produced image carrier protecting agent block, and FIG. 4 is a schematic cross-sectional view showing an example in which the image carrier protecting agent block of FIG. 3 is attached to a holder.

  Next, a protective layer forming apparatus using the image carrier protecting agent block manufactured by the above method as an image carrier protecting agent, a process cartridge including the protective layer forming apparatus, and an image forming apparatus will be described. .

(Protective layer forming device)
FIG. 5 is a schematic configuration diagram showing a main part of an example of the configuration of an image forming unit of an image forming apparatus provided with the protective layer forming apparatus of the present invention.
A protective layer forming apparatus 2 disposed opposite to a drum-shaped image carrier (for example, a photosensitive drum) 1 is a quadrangular prism, hexagonal column, or circle formed by compressing the protective agent for protecting the image carrier 1 as described above. The image carrier protecting agent 21 solidified in a columnar block or the like, and a brush-like member (for example, a brush roller) that rotates in contact with the image carrier protecting agent 21 and has a brush shape from the image carrier protecting agent 21. The protective agent supply member 22 for supplying the protective agent transferred to the member to the image carrier 1 and the image carrier protective agent 21 against the brush-like member of the protective agent supply member 22 to apply the protective agent to the protective agent supply member 22. A pressing force applying mechanism 23 for shifting to a brush-like member, a protective layer forming mechanism 24 having a layer forming member for thinning the protective agent supplied onto the image carrier by the protective agent supply member 22, and a protective agent 21. Support to prevent swinging back and forth Mamoruzai is mainly composed of the supporting member (holder) 25 and the like. A cleaning mechanism (cleaning device) 4 is disposed upstream of the protective agent supply member 22 in the moving direction (rotation direction) of the image carrier surface indicated by an arrow in the figure. It can also be regarded as a part of the protective layer forming apparatus 2. Further, the arrangement of the image carrier protecting agent 21 and the protecting agent supply member 22 is merely an example, and is not limited thereto.

In the present invention, the image carrier protecting agent 21 comes into contact with the protecting agent supply member 22 made of, for example, a brush-like member, by a pressing force from a pressing force applying mechanism 23 made of a member such as a spring or a spring. The protective agent supply member 22 rotates and rubs with the image carrier 1 with a linear velocity difference. At this time, the image carrier protective agent 21 held on the surface of the protective agent supply member is supplied to the surface of the image carrier.
The image carrier protecting agent 21 supplied to the surface of the image carrier may not be a sufficient protective layer at the time of supply depending on the selection of the material type. Therefore, in order to form a more uniform protective layer, for example, a layer forming member The image bearing member is thinned by a protective layer forming mechanism 24 having a blade-shaped member and a pressing member (not shown) such as a spring or a spring that presses the blade-shaped member against the surface of the photoreceptor 1. It becomes a protective layer on the surface.

The image carrier 1 on which the protective layer is formed is, for example, a charging member (for example, a charging member) to which a DC bias voltage or a charging bias voltage obtained by superimposing an AC bias voltage is applied by a voltage application device such as a high voltage power source (not shown). The roller 3) is brought into contact with or in close proximity to charge the image carrier by discharge in a minute gap. At this time, a part of the protective layer is decomposed or oxidized due to electrical stress, and air discharge products adhere to the surface of the protective layer, resulting in a deteriorated product.
The deteriorated image carrier protective agent is removed by a cleaning mechanism together with components such as toner remaining on the image carrier by a normal cleaning mechanism. Such a cleaning mechanism may also be used as the protective layer forming mechanism 24 described above. However, the function of removing the image carrier surface residue and the function of forming the protective layer are based on the state of rubbing between appropriate members. In the configuration shown in FIG. 5, the functions are separated, and the cleaning blade, the cleaning pressing mechanism, and the like are disposed upstream of the image carrier protecting agent supply unit in the moving direction (rotation direction) of the image carrier 1. A cleaning mechanism (cleaning device) 4 is provided.

(Process cartridge)
Next, an embodiment of a process cartridge according to the present invention will be described.
The process cartridge of the present invention includes at least the image carrier 1 and the protective layer forming device 2 as a unit, and further integrates a charging device, an exposure device, a developing device, a cleaning device, and the like as necessary. Have.
The process cartridge of the present invention can be detachably provided in various electrophotographic image forming apparatuses, and is preferably detachably provided in the image forming apparatus of the present invention described later.

Here, FIG. 6 is a schematic cross-sectional view for explaining an outline of a configuration example of a process cartridge using the protective layer forming apparatus according to the present invention. This process cartridge is detachably attached to the image forming unit 10 of the image forming apparatus according to the present invention.
An image forming unit 10 shown in FIG. 6 includes an image carrier (for example, a photosensitive drum) 1, a charging device (charging roller in the illustrated example) 3 that is a charging unit that charges the image carrier 1, and a charged image. An electrostatic latent image forming means (not shown) for forming an electrostatic latent image by irradiating the carrier 1 with a laser beam L or the like, and developing the electrostatic latent image on the image carrier 1 with toner to make it visible A developing device 5 which is a developing means for forming an image (toner image), a transfer means 6 for transferring a toner image on the image carrier 1 to a transfer medium (recording medium such as paper or an intermediate transfer body) 7, and after transfer The cleaning device 4 is a cleaning unit that removes toner remaining on the surface of the image carrier 1, and the protective layer forming device 2 is disposed in a portion from the cleaning device 4 to the charging device 3. The image forming unit 10 is configured using a process cartridge 11 in which a protective layer forming device 2, a charging device 3, a developing device 5, and a cleaning device 4 are integrally provided in a cartridge together with the image carrier 1. Yes. In the present embodiment, the cleaning device 4 cleans the surface of the photosensitive member before supplying the protective agent so that the protective agent is satisfactorily applied. Therefore, the moving direction of the image carrier 1 ( It is provided downstream of the transfer means 6 in the rotation direction) and upstream of the protective layer forming apparatus 2.

In the process cartridge 11, the protective layer forming device 2 disposed opposite to the photosensitive drum as the image carrier 1 includes an image carrier protective agent 21, a protective agent supply member 22, a pressing force applying mechanism 23, and a protective member. It is comprised from the layer formation mechanism 24, the protective agent support member (holder) 25, etc.
Further, the image carrier 1 has a surface on which the image carrier protective agent or toner component partially deteriorated after the transfer process remains, but the surface residue is cleaned by the cleaning member 41 of the cleaning device 4. To be cleaned. In FIG. 6, the cleaning member 41 is a cleaning blade abutted at an angle similar to a so-called counter type (leading type).
The protective layer forming mechanism 24 includes a blade-like member (hereinafter referred to as a blade) 24a that is a layer forming member, and a pressing member 24b such as a spring or a spring that presses the blade 24a against the surface of the photoreceptor 1. The blade 24a is not a counter type in the illustrated example, but the blade 24a may also be abutted at an angle similar to the counter type.

The image carrier protective agent 21 is supplied from the protective agent supply member 22 of the protective layer forming device 2 to the surface of the image carrier from which the residual toner on the surface and the deteriorated image carrier protective agent have been removed by the cleaning device 4. The protective layer forming mechanism 24 forms a film-like protective layer. At this time, the image carrier protecting agent 21 used in the present invention can stably and stably supply the necessary and sufficient amount to the surface of the image carrier with good controllability. Thus, the deterioration of the image carrier itself can be prevented.
The image carrier 1 having the protective layer formed in this way is charged by the charging device (charging roller) 3, and then an electrostatic latent image is formed by exposure L such as a laser, and is developed by the developing device 5 to be visible. An image is formed and transferred to a transfer medium (recording medium such as paper or an intermediate transfer member) 7 by transfer means (transfer roller or the like) 6 outside the process cartridge.

  As described above, the process cartridge 11 according to the present invention is excellent in an allowable range with respect to fluctuations in the surface state of the image carrier, and has a configuration in which fluctuations in charging performance to the image carrier are highly suppressed. By using the process cartridge 11 in the image forming unit of the image forming apparatus, it is possible to stably form an extremely high quality image over a long period of time.

(Configuration example of image forming apparatus)
Next, FIG. 7 is a schematic configuration diagram showing an example of the image forming apparatus 100 including the protective layer forming apparatus of the present invention.
The image forming apparatus 100 includes an image forming apparatus main body (printer unit) 110 that performs image formation, a document reading unit (scanner unit) 120 installed on the upper part of the main unit 110, and an automatic document supply unit installed thereon. A paper device (ADF) 130 and a paper feed unit 200 installed at the lower part of the image forming apparatus main body 110 are provided, and have a function of a copying machine. The image forming apparatus 100 has a communication function with an external device, and can be used as a printer or a scanner by connecting to a personal computer or the like outside the device via a LAN. Further, it can be used as a facsimile by connecting to a telephone line or an optical line.

  In the image forming apparatus main body 110, four image forming portions (for example, process cartridges shown in FIG. 6) 10 having the same configuration and different toner colors of the developing device 5 are arranged in parallel, and the four image forming portions ( The process cartridge 10 forms images with different toner colors (for example, yellow (Y), magenta (M), cyan (C), and black (K) images), and each color toner image is transferred to a transfer medium or an intermediate transfer medium. Multi-color or full-color images can be formed by overlaying and transferring. In the example of FIG. 7, the four image forming units 10 are arranged in parallel along a belt-shaped transfer medium (hereinafter referred to as an intermediate transfer member) 7 stretched around a plurality of rollers. The toner images of the respective colors formed by the forming unit are sequentially transferred to the intermediate transfer member 7 in order, and then transferred to a sheet-like recording medium such as paper by the secondary transfer device 12.

  The image forming unit 10 for each color has the same configuration as that in FIG. 6, and a protective layer forming device 2, a charging device 3, and an exposure device are disposed around an image carrier (for example, a photosensitive drum) 1 (1 Y, 1 M, 1 C, 1 K). An exposure unit such as a laser beam from the device 8, a developing device 5, a primary transfer device 6, and a cleaning device 4 are arranged. Similarly to FIG. 6, each color image forming unit 10 has a process cartridge in which a protective layer forming device 2, a charging device 3, a developing device 5, and a cleaning device 4 are integrally provided in a cartridge together with the photoreceptor 1. 11 is used. The process cartridge 11 is detachably attached to the image forming apparatus main body 110.

Next, the operation of the image forming apparatus shown in FIG. 7 will be described. Here, a series of processes for image formation will be described using a negative-positive process. The operation of each image forming unit is the same.
Image carriers 1Y, 1M, 1C, and 1K typified by a photoreceptor (OPC) having an organic photoconductive layer are neutralized by a static elimination lamp (not shown) or the like, and uniformly negative by a charging device 3 having a charging member. Is charged.
When the image bearing member is charged by the charging device, the image bearing member 1Y, 1G, is supplied from a voltage applying device (not shown) to a charging member (for example, a charging roller disposed in contact with or close to the image bearing member). A charging bias voltage obtained by superimposing an AC bias voltage on a DC bias voltage of an appropriate magnitude suitable for charging 1M, 1C, and 1K to a desired potential is applied.
The charged image carriers 1Y, 1M, 1C, and 1K form a latent image with laser light corresponding to image data irradiated by an exposure device 8 including exposure means such as a laser optical system (the absolute value of the exposure portion potential is , The potential becomes lower than the absolute value of the non-exposed portion potential).
Laser light is emitted from a semiconductor laser, and the surfaces of the image carriers 1Y, 1M, 1C, and 1K are moved along the rotation axis direction of the image carrier (main scanning direction) by a polygonal polygon mirror that rotates at high speed. Scan).
The latent image formed in this way is developed with a developer made of toner particles or a mixture of toner particles and carrier particles supplied on the developing sleeve of the developing roller 51 which is a developer carrying member in the developing device 5. As a result, a visible image of the toner is formed.
At the time of developing the latent image, a voltage of an appropriate magnitude or a voltage between the exposed portion and the non-exposed portion of the image carrier 1Y, 1M, 1C, 1K is applied to the developing sleeve from a voltage application mechanism (not shown). A developing bias superimposed with an AC voltage is applied.

The toner images formed on the image carriers 1Y, 1M, 1C, and 1K corresponding to the respective colors by the operation as described above are primarily transferred onto the intermediate transfer body 7 by the primary transfer device 6 in order. On the other hand, in synchronization with the image forming operation and the primary transfer operation, the paper feed roller 202 and the separation roller are selected from the paper feed cassettes selected from the multi-stage paper feed cassettes 201a, 201b, 201c, and 201d of the paper feed unit 200. A sheet-like recording medium such as paper is fed by a paper feeding mechanism 203, and is conveyed to a secondary transfer unit via conveying rollers 204, 205, 206 and registration rollers 207. In the secondary transfer portion, the toner image on the intermediate transfer member 7 is secondarily transferred to the conveyed recording medium by a secondary transfer device (for example, a secondary transfer roller) 12. In the above transfer step, it is preferable that a potential having a polarity opposite to the charging polarity of the toner is applied to the primary transfer device 6 and the secondary transfer device 12 as a transfer bias.
After the secondary transfer described above, the recording medium is separated from the intermediate transfer member 7 to obtain a transfer image. Further, the toner particles remaining on the photosensitive member 1 after the primary transfer are collected into the toner collecting chamber in the cleaning device 4 by the cleaning member 41 of the cleaning device 4. Further, the toner particles remaining on the intermediate transfer body 7 after the secondary transfer are collected in a toner collection chamber in the belt cleaning device 9 by the cleaning member of the belt cleaning device 9.

  An image forming apparatus 100 shown in FIG. 7 is a so-called tandem type intermediate transfer type image forming apparatus in which a plurality of the above-described image forming units (process cartridges) 10 are arranged along the intermediate transfer body 7. A plurality of toner images having different colors, which are sequentially created on the respective photoreceptors 1Y, 1M, 1C, and 1K by the image forming unit 10, are sequentially transferred onto the intermediate transfer body 7 and then collectively transferred to a sheet of paper. Transfer to recording medium. Then, the recording medium onto which the toner image has been transferred is sent to the fixing device 14 by the transport device 13 and the toner is fixed by heating, pressing, or the like. The recording medium after fixing is discharged to a discharge tray 17 by a transport device 15 and a discharge roller 16. The image forming apparatus 100 also has a double-sided printing function. During double-sided printing, the conveyance path downstream of the fixing device 14 is switched, and a recording medium on which a single-sided image is fixed is transferred through the double-sided conveyance apparatus 210. The paper is reversed, and is fed again to the secondary transfer unit by the transport roller 206 and the registration roller 207, and the image is transferred to the back side. The recording medium after transfer is conveyed to the fixing device 14 in the same manner as described above to fix the image, and the recording medium after fixing is discharged to a discharge tray 17.

  In the above configuration, the intermediate transfer member can be used without using an intermediate transfer member, and a tandem type direct transfer method image forming apparatus can be used. In the case of this direct transfer method, a recording medium is supported instead of the intermediate transfer member. Using a transfer belt or the like that transports, a plurality of toner images of different colors, which are sequentially created on each photoreceptor 1 (1Y, 1M, 1C, 1K) by each image forming unit 10, are directly transported by the transfer belt. Alternatively, the toner may be fixed to the recording medium after being sequentially transferred to the fixing device 14 by heating and pressurizing.

In the image forming apparatus as described above, the charging device 3 is preferably a charging device in which a charging member such as a charging roller is disposed in contact with or in close proximity to the surface of the image carrier. Compared with a so-called corotron or socorotron using a corona discharger, the amount of ozone generated during charging can be greatly suppressed.
However, in the charging device 3 that charges such a charging member in contact with or close to the surface of the image carrier, the discharge is performed in the region near the surface of the image carrier as described above. Tend to be stressful. Therefore, the image carrier is deteriorated over a long period of time by using the protective layer forming apparatus 2 using the image carrier protective agent 21 according to the present invention and further executing the image carrier refresh mode described later. Therefore, image fluctuations over time and image fluctuations due to the use environment can be greatly suppressed, and stable image quality can be ensured.

Next, each part of the protective layer forming apparatus 2 used in the image forming apparatus of the present invention will be described in more detail.
The material of the layer forming member (blade) used for the protective layer forming mechanism 24 of the protective layer forming apparatus 2 is not particularly limited. For example, urethane rubber, hydrin rubber, silicone rubber, fluorine, which are generally known as cleaning blade materials, are used. Elastic bodies such as rubber can be used alone or in combination. Further, these rubber blades may be coated or impregnated with a low friction coefficient material at the contact portion with the image carrier. Further, in order to adjust the hardness of the elastic body, fillers represented by other organic fillers and inorganic fillers may be dispersed.

For example, as shown in FIG. 6, these blades are fixed to the blade support by an arbitrary method such as adhesion or fusion so that the tip can be pressed against the surface of the image carrier. The blade thickness cannot be uniquely defined in consideration of the force applied by pressing, but can be preferably used if it is about 0.5 to 5 mm, and more preferably about 1 to 3 mm.
Also, the length of the blade that protrudes from the support and can bend, that is, the so-called free length, is applied by pressing in the same manner, but it cannot be uniquely defined in terms of force, but is approximately 1 to 15 mm. If it is about 2-10 mm, it can be preferably used.

As another configuration of the protective layer forming blade member, a layer of resin, rubber, elastomer or the like is coated on the surface of an elastic metal blade such as a spring plate, if necessary, via a coupling agent, a primer component, etc. It may be formed by a method, and if necessary, heat curing or the like, and if necessary, surface polishing or the like may be applied.
The thickness of the elastic metal blade is preferably about 0.05 to 3 mm, and more preferably about 0.1 to 1 mm.
Moreover, in an elastic metal blade, in order to suppress the twist of a braid | blade, you may perform processes, such as a bending process, in the direction substantially parallel to a spindle after attachment.
As a material for forming the surface layer, fluorine resin such as PFA, PTFE, FEP, PVdF, silicone elastomer such as fluorine rubber, methylphenyl silicone elastomer, and the like can be used together with a filler, if necessary. It is not limited to this.

  Further, the force for pressing the image carrier with the blade 24a of the protective layer forming mechanism 24 is sufficient as the image carrier protective agent spreads to form a protective layer or a protective film, and the linear pressure is 5 gf / cm or more. It is preferably 80 gf / cm or less, and more preferably 10 gf / cm or more and 60 gf / cm or less.

The brush-like member of the protective layer forming apparatus 2 is preferably used as the protective agent supply member 22, but in this case, the brush fiber has flexibility in order to suppress mechanical stress on the surface of the image carrier. Is preferred.
As a specific material of the flexible brush fiber, one or more kinds can be selected and used from generally known materials. Specifically, polyolefin resins (for example, polyethylene, polypropylene); polyvinyl and polyvinylidene resins (for example, polystyrene, acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether and Polyvinyl chloride); vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; styrene-butadiene resin; fluorine resin (for example, polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene); Polyester; Nylon; Acrylic; Rayon; Polyurethane; Polycarbonate; Phenol resin; Amino resin (eg urea-formaldehyde resin, melamine) Fat, benzoguanamine resins, urea resins, polyamide resins); Among such, may be a resin having flexibility.
Also, in order to adjust the degree of bending, diene rubber, styrene-butadiene rubber (SBR), ethylene propylene rubber, isoprene rubber, nitrile rubber, urethane rubber, silicone rubber, hydrin rubber, norbornene rubber, etc. are used in combination. Also good.

The support for the protective agent supply member 22 includes a fixed type and a rotatable roller type. In the present invention, a rotatable roller type is used. As a roller-shaped supply member, for example, there is a roller roller in which a tape having brush fibers piled is wound around a metal core bar in a spiral shape. The brush fiber has a fiber diameter of about 10 to 500 μm, the length of the brush fiber is 1 to 15 mm, and the brush density is 10,000 to 300,000 per square inch (1.5 × 10 ^{7 to} 4.5 × 10 per square meter). ⁸ ) are preferably used.

  The protective agent supply member 22 is preferably made of a material having a very high brush density in terms of supply uniformity and stability, and one fiber is made from several to several hundreds of fine fibers. Is also preferable. For example, bundling 50 fine fibers of 6.7 decitex (6 denier), such as 333 decitex = 6.7 decitex × 50 filament (300 denier = 6 denier × 50 filament), and implanting as one fiber Is also possible.

  Moreover, you may provide a coating layer in the brush surface for the purpose of stabilizing the surface shape of a brush, environmental stability, etc. as needed. As a component constituting the coating layer, it is preferable to use a coating layer component that can be deformed according to the bending of the brush fiber, and these are not limited as long as the material can maintain flexibility. Polyolefin resins such as polyethylene, polypropylene, chlorinated polyethylene, chlorosulfonated polyethylene, etc .; polystyrene, acrylic (for example, polymethyl methacrylate), polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, Polyvinyl and polyvinylidene resins such as polyvinyl carbazole, polyvinyl ether, and polybiliketones; vinyl chloride-vinyl acetate copolymers; silicone resins composed of organosiloxane bonds or modified products thereof (for example, alkyd resins, Modified products by reester resin, epoxy resin, polyurethane, etc.); Fluororesin such as perfluoroalkyl ether, polyfluorovinyl, polyfluorovinylidene, polychlorotrifluoroethylene; polyamide; polyester; polyurethane; polycarbonate; urea-formaldehyde resin, etc. Amino resins; epoxy resins, composite resins of these, and the like.

Next, a photoconductor suitably used as an image carrier in the image forming apparatus of the present invention will be described.
In the photoreceptor used in the image forming apparatus of the present invention, a photosensitive layer is provided on a conductive support. The photosensitive layer is composed of a single layer type in which a charge generation material and a charge transport material are mixed, a forward layer type in which a charge transport layer is provided on the charge generation layer, or a charge generation layer provided on the charge transport layer. There is a reverse layer type. In addition, a protective layer can be provided on the photosensitive layer in order to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property, and the like of the photoreceptor. An undercoat layer may be provided between the photosensitive layer and the conductive support. In addition, an appropriate amount of a plasticizer, an antioxidant, a leveling agent and the like can be added to each layer as necessary.

  As the conductive support of the photosensitive member, one having a volume resistance of 10 ^ 10 Ω · cm or less, for example, metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, oxidation A metal oxide such as indium is deposited or sputtered on a film or cylindrical plastic or paper, or a plate of aluminum, aluminum alloy, nickel, stainless steel, etc. After forming the tube into a drum shape, it is possible to use a tube that has been surface-treated by cutting, superfinishing, polishing, or the like. A drum-shaped support having a diameter of 20 to 150 mm, preferably 24 to 100 mm, and more preferably 28 to 70 mm can be used. If the diameter of the drum-shaped support is 20 mm or less, it is physically difficult to arrange the charging, exposure, development, transfer, and cleaning steps around the drum. If the diameter of the drum-shaped support is 150 mm or more, image formation is performed. The apparatus becomes undesirably large. In particular, when the image forming apparatus is a tandem type, it is necessary to mount a plurality of photoconductors, and thus the diameter is preferably 70 mm or less, and preferably 60 mm or less. Further, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can also be used as the conductive support.

  As the undercoat layer of the photosensitive member used in the image forming apparatus of the present invention, a resin or a material mainly composed of a white pigment and a resin, and a metal oxide film obtained by chemically or electrochemically oxidizing the surface of a conductive substrate Etc., but those containing a white pigment and a resin as main components are preferred. Examples of the white pigment include metal oxides such as titanium oxide, aluminum oxide, zirconium oxide, and zinc oxide. Among them, it is most preferable to contain titanium oxide that is excellent in preventing charge injection from the conductive substrate. As the resin used for the undercoat layer, thermoplastic resins such as polyamide, polyvinyl alcohol, casein, and methyl cellulose, thermosetting resins such as acrylic, phenol, melamine, alkyd, unsaturated polyester, and epoxy, one or various kinds of these Mixtures can be exemplified.

  Examples of the charge generating material for the photoreceptor used in the image forming apparatus of the present invention include azo pigments such as monoazo pigments, bisazo pigments, trisazo pigments, and tetrakisazo pigments, triarylmethane dyes, thiazine dyes, and oxazines. Dyes, xanthene dyes, cyanine dyes, styryl dyes, pyrylium dyes, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, bisbenzimidazole pigments, indanthrone pigments, squarylium pigments Inorganic materials such as pigments, organic pigments and dyes such as phthalocyanine pigments, selenium, selenium-arsenic, selenium-tellurium, cadmium sulfide, zinc oxide, titanium oxide, and amorphous silicon can be used. It can be used alone or in combination. The undercoat layer may be a single layer or a plurality of layers.

  Examples of the charge transport material for the photoreceptor used in the image forming apparatus of the present invention include anthracene derivatives, pyrene derivatives, carbazole derivatives, tetrazole derivatives, metallocene derivatives, phenothiazine derivatives, pyrazoline compounds, hydrazone compounds, styryl compounds, styryl hydrazone compounds, Enamine compounds, butadiene compounds, distyryl compounds, oxazole compounds, oxadiazole compounds, thiazole compounds, imidazole compounds, triphenylamine derivatives, phenylenediamine derivatives, aminostilbene derivatives, triphenylmethane derivatives, etc. can do.

  The binder resin used to form the photosensitive layer of the charge generation layer and the charge transport layer is electrically insulating and is a known thermoplastic resin, thermosetting resin, photocurable resin, and photoconductive material. Suitable binder resins include, for example, polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, Ethylene-vinyl acetate copolymer, polyvinyl butyral, polyvinyl acetal, polyester, phenoxy resin, (meth) acrylic resin, polystyrene, polycarbonate, polyarylate, thermoplastic resin such as polysulfone, polyethersulfone, ABS resin, phenol resin , Epoxy resin, urethane resin, melamine resin, isocyanate resin, alkyd resin, Examples thereof include a thermosetting resin such as a ricone resin, a thermosetting acrylic resin, a type of binder resin such as a photoconductive resin such as polyvinyl carbazole, polyvinyl anthracene, and polyvinyl pyrene, or a mixture of various types of binder resins. In particular, it is not limited to these.

As antioxidant, the following are used, for example.
Monophenol compounds 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di-t -Butyl-4-hydroxyphenyl) propionate, 3-t-butyl-4-hydroxynisol and the like.

Bisphenol compounds 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2′-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4′- Thiobis- (3-methyl-6-tert-butylphenol), 4,4′-butylidenebis- (3-methyl-6-tert-butylphenol) and the like.

High molecular phenol compound 1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5 -Di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3' -Bis (4'-hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, tocophenols and the like.

Paraphenylenediamines N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N , N′-di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine, and the like.

Hydroquinones 2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2 -Octadecenyl) -5-methylhydroquinone and the like.

Organic sulfur compounds Dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like.

Organic phosphorus compounds such as triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine and the like.

As the plasticizer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is about 0 to 30 parts by weight with respect to 100 parts by weight of the binder resin. Is appropriate.
A leveling agent may be added to the charge transport layer. As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the chain are used, and the amount used is 100 parts by weight of binder resin. 0 to 1 part by weight is suitable.

  As described above, the surface layer is provided to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property, etc. of the photoreceptor. Examples of the surface layer include a polymer having a mechanical strength higher than that of the photosensitive layer and a polymer in which an inorganic filler is dispersed. The polymer used for the surface layer may be either a thermoplastic polymer or a thermosetting polymer, but the thermosetting polymer has a high mechanical strength and does not wear due to friction with the cleaning blade. It is very preferable because of its extremely high ability to suppress. If the surface layer has a thin film thickness, there is no problem even if it does not have the charge transport capability. However, if the surface layer without the charge transport capability is formed thick, the sensitivity of the photoreceptor decreases, the potential increases after exposure, and the residual layer remains. Since the potential rise is likely to occur, it is preferable to use the above-mentioned charge transporting substance in the surface layer or to use a polymer having a charge transporting capability for the protective layer. When the surface layer is provided, the mechanical strength of the photosensitive layer and the surface layer is generally greatly different, and therefore the protective layer is worn away due to friction with the cleaning blade. It is important that the surface layer has a sufficient film thickness, and is 0.01 to 12 μm, preferably 1 to 10 μm, more preferably 2 to 8 μm. If the film thickness of the surface layer is 0.1 μm or less, it is not preferable because it is too thin and easily disappears due to friction with the cleaning blade, and wear of the photosensitive layer proceeds from the disappeared portion. When the film thickness of the surface layer is 12 μm or more, the sensitivity is lowered, the potential after exposure is increased, and the residual potential is likely to be increased. This is not preferable.

  The polymer used for the surface layer is preferably a material that is transparent to the writing light during image formation and has excellent insulation, mechanical strength, and adhesiveness. ABS resin, ACS resin, olefin-vinyl monomer copolymer , Chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethyl Examples include resins such as bentene, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polyvinylidene chloride, and epoxy resin. . These polymers may be thermoplastic polymers, but in order to increase the mechanical strength of the polymers, they are crosslinked with a crosslinking agent having a polyfunctional acryloyl group, carboxyl group, hydroxyl group, amino group, etc. By using a curable polymer, the mechanical strength of the surface layer is increased, and wear due to friction with the cleaning blade can be greatly reduced.

  As described above, it is preferable that the surface layer has a charge transport capability. In order to provide the surface layer with a charge transport capability, a polymer used for the surface layer and the above-described charge transport material are mixed. A method of using a polymer having a charge transporting capability for the surface layer is conceivable, and the latter method is preferable because it can obtain a photoconductor with high sensitivity and little increase in potential after exposure and little increase in residual potential.

The image carrier of the present invention is an intermediate used for image formation by a so-called intermediate transfer method in which a toner image formed on a photoreceptor is primarily transferred to perform color superposition and further transferred to a transfer medium. It may be a transfer medium.
As the intermediate transfer medium, a medium having a volume resistance of 10 ^ 5 to 10 ^ 11 Ω · cm is preferable. When the surface resistance is less than 10 ^ 5Ω / □, when transferring the toner image from the photoconductor onto the intermediate transfer medium, so-called transfer dust may be generated in which the toner image is disturbed due to discharge. If it exceeds 11Ω / □, after the toner image is transferred from the intermediate transfer medium to a transfer medium such as paper, the counter charge of the toner image remains on the intermediate transfer medium and appears as a residual image on the next image. is there.

As an intermediate transfer medium, for example, a metal oxide such as tin oxide or indium oxide, or conductive particles such as carbon black or a conductive polymer, alone or in combination, kneaded with a thermoplastic resin, and then extruded into a belt shape Alternatively, a cylindrical plastic can be used. In addition to this, the above-mentioned conductive particles and conductive polymer are added to a resin solution containing a thermal crosslinking reactive monomer or oligomer, if necessary, and subjected to centrifugal molding while heating to obtain an intermediate transfer medium on an endless belt. You can also
When providing a surface layer on the intermediate transfer medium, among the surface layer materials used for the above-mentioned photoreceptor surface layer, the composition excluding the charge transport material is appropriately adjusted in combination with a conductive substance, Can be used.

Next, the toner suitably used in the present invention will be described.
First, the toner of the present invention preferably has an average circularity of 0.93 to 1.00. In the present invention, the value obtained from the following formula (1) is defined as circularity. This circularity is an index of the degree of unevenness of the toner particles, and indicates 1.00 when the toner is a perfect sphere, and the circularity becomes smaller as the surface shape becomes more complicated.
Circularity SR = perimeter of a circle having the same area as the particle projection area / perimeter of the particle projection image (1)

When the average circularity is in the range of 0.93 to 1.00, the surface of the toner particles is smooth, and the contact area between the toner particles and between the toner particles and the photosensitive member is small, so that the transferability is excellent.
Since the toner particles have no corners, the developer agitation torque in the developing device is small, and the agitation drive is stabilized, so that no abnormal image is generated.
Since there are no angular toner particles in the toner that forms the dots, when the pressure is brought into contact with the transfer medium during the transfer, the pressure is uniformly applied to the entire toner that forms the dots, and the transfer is not easily lost.
Since the toner particles are not angular, the abrasive power of the toner particles themselves is small, and the surface of the image carrier is not damaged or worn.

Next, a method for measuring the circularity will be described.
The circularity can be measured using a flow type particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics.
As a specific measuring method, 0.1 to 0.5 ml of a surfactant, preferably alkylbenzene sulfonate is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance, and further measurement is performed. Add about 0.1-0.5g of sample. The suspension in which the sample is dispersed is subjected to dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the shape and particle size of the toner are measured by the above apparatus with the dispersion concentration being 3000 to 10000 / μl.

In the present invention, the weight average diameter D4 of the toner is preferably 3 to 10 μm.
In this range, since the toner particles have a sufficiently small particle size with respect to the minute latent image dots, the dot reproducibility is excellent.
When the weight average diameter D4 is less than 3 μm, phenomena such as a decrease in transfer efficiency and a decrease in blade cleaning properties tend to occur.
When the weight average diameter D4 exceeds 10 μm, it is difficult to suppress scattering of characters and lines.

In the toner of the present invention, the ratio of the weight average diameter D4 to the number average diameter D1 (D4 / D1) is preferably 1.00 to 1.40. The closer the value of (D4 / D1) is to 1, the sharper the particle size distribution of the toner.
Therefore, when (D4 / D1) is in the range of 1.00 to 1.40, the selective development due to the toner particle size does not occur, and the stability of the image quality is excellent.
Since the toner particle size distribution is sharp, the triboelectric charge amount distribution is also sharp, and fogging is suppressed.
When the toner particle diameter is uniform, the latent image dots are developed so as to be arranged in a precise and orderly manner, so that the dot reproducibility is excellent.

Next, a method for measuring the particle size distribution of toner particles will be described.
Examples of the measuring device for the particle size distribution of toner particles by the Coulter counter method include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). The measurement method is described below.
First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 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, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as the aperture. Volume distribution and number distribution are calculated. From the obtained distribution, the weight average diameter D4 and the number average diameter D1 of the toner can be obtained.
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; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

  In addition, as such a substantially spherical toner, a toner composition containing a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent in an aqueous medium in the presence of fine resin particles. A toner that undergoes crosslinking and / or elongation reaction is preferred. The toner produced by this reaction can reduce the hot offset by curing the toner surface, and can prevent the fixing device from becoming dirty and appearing on the image.

Examples of the prepolymer comprising a modified polyester resin that can be used for toner preparation include a polyester prepolymer (A) having an isocyanate group, and examples of a compound that extends or crosslinks with the prepolymer include amines (B). Can be mentioned.
Examples of the polyester prepolymer (A) having an isocyanate group include a product obtained by further reacting a polyester having an active hydrogen group with a polyisocyanate (3), which is a polycondensate of polyol (1) and polycarboxylic acid (2). Can be mentioned. Examples of the active hydrogen group possessed by the polyester include hydroxyl groups (alcoholic hydroxyl groups and phenolic hydroxyl groups), amino groups, carboxyl groups, mercapto groups, and the like. Among these, alcoholic hydroxyl groups are preferred.

  Examples of the polyol (1) include a diol (1-1) and a tri- or higher valent polyol (1-2). (1-1) alone or (1-1) and a small amount of (1-2) Mixtures are preferred. Diol (1-1) includes alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide phenol compound (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. The trihydric or higher polyol (1-2) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

  Examples of the polycarboxylic acid (2) include dicarboxylic acid (2-1) and trivalent or higher polycarboxylic acid (2-2). (2-1) alone and (2-1) with a small amount of ( The mixture of 2-2) is preferred. Dicarboxylic acid (2-1) includes alkylene dicarboxylic acid (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acid (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acid (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polycarboxylic acid (2-2) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (trimellitic acid, pyromellitic acid, and the like). In addition, as polycarboxylic acid (2), you may make it react with polyol (1) using the acid anhydride or lower alkyl ester (methyl ester, ethyl ester, isopropyl ester, etc.) of the above-mentioned thing.

  The ratio of the polyol (1) to the polycarboxylic acid (2) is usually 2/1 to 1/1, preferably 1. as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. 5/1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

  Examples of the polyisocyanate (3) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); Diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates; polyisocyanates such as phenol derivatives, oximes, caprolactams, etc. And a combination of two or more of these.

  The ratio of the polyisocyanate (3) is usually 5/1 to 1/1, preferably 4 /, as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. If the molar ratio of [NCO] is less than 1, the urea content in the modified polyester will be low, and the hot offset resistance will deteriorate. The content of the polyisocyanate (3) component in the prepolymer (A) having an isocyanate group at the terminal is usually 0.5 to 40% by weight, preferably 1 to 30% by weight, more preferably 2 to 20% by weight. It is. If it is less than 0.5% by weight, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40% by weight, the low-temperature fixability deteriorates.

  The number of isocyanate groups contained per molecule in the prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2.5 on average. It is. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

  As amines (B), diamine (B1), trivalent or higher polyamine (B2), aminoalcohol (B3), aminomercaptan (B4), amino acid (B5), and amino acids B1-B5 blocked (B6) etc. are mentioned. Examples of the diamine (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′dimethyldicyclohexylmethane, diaminecyclohexane, Isophorone diamine etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine etc.) and the like. Examples of the trivalent or higher polyamine (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of the B1 to B5 amino group blocked (B6) include ketimine compounds and oxazoline compounds obtained from the B1 to B5 amines and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

  Furthermore, if necessary, the molecular weight of the urea-modified polyester can be adjusted using an elongation terminator. Examples of the elongation terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

  The ratio of amines (B) is the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). The ratio is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] exceeds 2 or less than 1/2, the molecular weight of the urea-modified polyester (i) becomes low, and the hot offset resistance deteriorates. In the present invention, the polyester (i) modified with a urea bond may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

  By these reactions, the modified polyester used in the toner of the present invention, especially the urea-modified polyester (i) can be prepared. These urea-modified polyesters (i) are produced by a one-shot method or a prepolymer method. The weight average molecular weight of the urea-modified polyester (i) is usually 10,000 or more, preferably 20,000 to 10,000,000, more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the urea-modified polyester is not particularly limited when the unmodified polyester (ii) described later is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. (I) When used alone, the number average molecular weight is usually 20000 or less, preferably 1000 to 10000, and more preferably 2000 to 8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color apparatus are deteriorated.

  In the present invention, not only the polyester (i) modified with a urea bond but also the polyester (ii) not modified can be contained as a binder resin component together with the (i). By using (ii) in combination, the low-temperature fixability and glossiness when used in a full-color apparatus are improved, which is preferable to single use. Examples of (ii) include the same polycondensates of polyol (1) and polycarboxylic acid (2) as in the polyester component (i) above, and preferred ones are also the same as (i). (Ii) is not limited to unmodified polyester, but may be modified with a chemical bond other than a urea bond, and may be modified with a urethane bond, for example. It is preferable that (i) and (ii) are at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Accordingly, the polyester component (i) and (ii) preferably have similar compositions. When (ii) is contained, the weight ratio of (i) and (ii) is usually 5/95 to 80/20, preferably 5/95 to 30/70, more preferably 5/95 to 25/75, Particularly preferred is 7/93 to 20/80. If the weight ratio of (i) is less than 5%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The peak molecular weight of (ii) is usually 1000-30000, preferably 1500-10000, more preferably 2000-8000. If it is less than 1000, heat-resistant storage stability will deteriorate, and if it exceeds 10,000, low-temperature fixability will deteriorate. The hydroxyl value of (ii) is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If it is less than 5, it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. The acid value of (ii) is usually 1-30, preferably 5-20. By having an acid value, it tends to be negatively charged.

  In the present invention, the glass transition point (Tg) of the binder resin is usually 50 to 70 ° C., preferably 55 to 65 ° C. If it is less than 50 ° C., the blocking of the toner during high temperature storage deteriorates, and if it exceeds 70 ° C., the low-temperature fixability becomes insufficient. Due to the coexistence of the urea-modified polyester resin, the dry toner of the present invention tends to have good heat-resistant storage stability even when the glass transition point is low, as compared with known polyester-based toners. As the storage elastic modulus of the binder resin, the temperature (TG ′) at which 10000 dyne / cm 2 is obtained at a measurement frequency of 20 Hz is usually 100 ° C. or higher, preferably 110 to 200 ° C. If it is less than 100 ° C., the resistance to hot offset deteriorates. As the viscosity of the binder resin, the temperature (Tη) at 1000 poise at a measurement frequency of 20 Hz is usually 180 ° C. or less, preferably 90 to 160 ° C. If it exceeds 180 ° C., the low-temperature fixability deteriorates. That is, TG ′ is preferably higher than Tη from the viewpoint of achieving both low temperature fixability and hot offset resistance. In other words, the difference between TG ′ and Tη (TG′−Tη) is preferably 0 ° C. or more. More preferably, it is 10 degreeC or more, Most preferably, it is 20 degreeC or more. The upper limit of the difference is not particularly limited. Further, from the viewpoint of achieving both heat-resistant storage stability and low-temperature fixability, the difference between Tη and Tg is preferably 0 to 100 ° C. More preferably, it is 10-90 degreeC, Most preferably, it is 20-80 degreeC.

  The binder resin can be produced by the following method. The polyol (1) and the polycarboxylic acid (2) are heated to 150 to 280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and the generated water is distilled off as necessary. Thus, a polyester having a hydroxyl group is obtained. Next, this is reacted with polyisocyanate (3) at 40 to 140 ° C. to obtain a prepolymer (A) having an isocyanate group. Further, (A) is reacted with amines (B) at 0 to 140 ° C. to obtain a polyester modified with a urea bond. When (3) is reacted and (A) and (B) are reacted, a solvent can be used as necessary. Usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers And those inert to the isocyanate (3), such as tetrahydrofuran (such as tetrahydrofuran). When polyester (ii) not modified with urea bond is used in combination, (ii) is produced by the same method as polyester having a hydroxyl group, and this is dissolved in the solution after completion of the reaction of (i) and mixed. To do.

Further, the toner used in the present invention can be produced generally by the following method, but is not limited thereto.
The aqueous medium used in the present invention may be water alone, or a solvent miscible with water may be used in combination. Examples of the miscible solvent include alcohol (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methylcellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.) and the like.

  The toner particles may be formed by reacting a dispersion composed of a prepolymer (A) having an isocyanate group in an aqueous medium with (B), or using a urea-modified polyester (i) produced in advance. good. As a method for stably forming a dispersion comprising urea-modified polyester (i) or prepolymer (A) in an aqueous medium, a toner raw material comprising urea-modified polyester (i) or prepolymer (A) in an aqueous medium is used. And a method of dispersing by shearing force. The prepolymer (A) and other toner compositions (hereinafter referred to as toner raw materials), a colorant masterbatch, a release agent, a charge control agent, an unmodified polyester resin, etc. are dispersed in an aqueous medium. It may be mixed at the time of formation, but it is more preferable to mix the toner raw materials in advance and then add and disperse the mixture in the aqueous medium. In the present invention, other toner materials such as a colorant, a release agent, and a charge control agent do not necessarily have to be mixed when forming particles in an aqueous medium, but after the particles are formed. , May be added. For example, after forming particles containing no colorant, the colorant can be added by a known dyeing method.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. In order to make the particle size of the dispersion 2 to 20 μm, a high-speed shearing type is preferable. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C. Higher temperatures are preferred in that the dispersion made of urea-modified polyester (i) or prepolymer (A) has a low viscosity and is easy to disperse.

  The amount of the aqueous medium used relative to 100 parts of the toner composition containing the urea-modified polyester (i) and the prepolymer (A) is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner composition is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical. Moreover, a dispersing agent can also be used as needed. It is preferable to use a dispersant because the particle size distribution becomes sharp and the dispersion is stable.

  In the step of synthesizing the urea-modified polyester (i) from the prepolymer (A), the amine (B) may be added and reacted before the toner composition is dispersed in the aqueous medium, or may be dispersed in the aqueous medium. An amine (B) may be added later to cause a reaction from the particle interface. In this case, urea-modified polyester is preferentially produced on the surface of the manufactured toner, and a concentration gradient can be provided inside the particles.

  Anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates and phosphates, alkylamines as dispersants for emulsifying and dispersing the oily phase in which the toner composition is dispersed in a liquid containing water Amine salts such as salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, imidazoline, alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, etc. Nonionic surfactants such as quaternary ammonium salt type cationic surfactants, fatty acid amide derivatives, polyhydric alcohol derivatives, such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl N, amphoteric surfactants such as N- dimethyl ammonium betaine and the like.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [omega-fluoroalkyl (C6 to C11). Sodium oxy] -1-alkyl (C3-C4) sulfonate, sodium 3- [omega-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonate, fluoroalkyl (C11-C20) carboxylic acid and Metal salt, perfluoroalkyl carboxylic acid (C7 to C13) and its metal salt, perfluoroalkyl (C4 to C12) sulfonic acid and its metal salt, perfluorooctane sulfonic acid diethanolamide, N-propyl-N- (2 hydroxy ethyl) -Fluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Is mentioned.

  Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Taikin Kogyo Co., Ltd.), Mega-Fac F-ll0, F-120, F-113, F-191, F-812, F-833 (Dainippon Ink Co., Ltd.), Xtop EF- 102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F-150 (manufactured by Neos).

  In addition, as the cationic surfactant, aliphatic quaternary ammonium salts such as aliphatic primary, secondary or secondary amic acid, perfluoroalkyl (C 6 -C 10) sulfonamidopropyltrimethylammonium salt which right the fluoroalkyl group, Benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, trade names include Surflon S-121 (Asahi Glass), Florard FC-135 (Sumitomo 3M), Unidyne DS-202 (Daikin Industries) ), Megafuck F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products Co., Ltd.), Footgent F-300 (Neos Co., Ltd.) and the like.

  Further, tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, hydroxyapatite and the like can be used as an inorganic compound dispersant which is hardly soluble in water.

  Further, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-acrylate Chloro-2-hydroxypropyl, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate, N -Methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or esters of compounds containing vinyl alcohol and carboxyl groups For example, pinyl acetate, pinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or acid chlorides such as these methylol compounds, acrylic acid chloride, methacrylic acid chloride, pinylviridine, vinylpyrrolidone, vinylimidazole, ethyleneimine Homopolymers or copolymers such as those having a nitrogen atom or its heterocyclic ring, polyoxyethylene, polyoxypropylene, Oxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonylphenyl Polyoxyethylenes such as esters, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

In addition, when an acid such as calcium phosphate salt or an alkali-soluble substance is used as the dispersion stabilizer, the calcium phosphate salt is removed from the fine particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. To do. It can also be removed by operations such as enzymatic degradation.
When a dispersant is used, the dispersant may remain on the surface of the toner particles, but it is preferable from the charged surface of the toner that the dispersant is washed and removed after the elongation and / or crosslinking reaction.

  Furthermore, in order to lower the viscosity of the toner composition, a solvent in which the urea-modified polyester (i) or the prepolymer (A) is soluble can be used. The use of a solvent is preferable in that the particle size distribution becomes sharp. The solvent is preferably volatile from the viewpoint of easy removal. Examples of the solvent include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, Methyl ethyl ketone, methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform and carbon tetrachloride are preferred, and aromatic solvents such as toluene and xylene are more preferred. The usage-amount of the solvent with respect to 100 parts of prepolymers (A) is 0-300 parts normally, Preferably it is 0-100 parts, More preferably, it is 25-70 parts. When a solvent is used, it is removed by heating under normal pressure or reduced pressure after elongation and / or crosslinking reaction.

  The elongation and / or cross-linking reaction time is selected depending on the reactivity of the isocyanate group structure of the prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. is there. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.

  In order to remove the organic solvent from the obtained emulsified dispersion, a method in which the temperature of the entire system is gradually raised to completely evaporate and remove the organic solvent in the droplets can be employed. Alternatively, the emulsified dispersion can be sprayed into a dry atmosphere to completely remove the water-insoluble organic solvent in the droplets to form toner fine particles, and the aqueous dispersant can be removed by evaporation together. . As a dry atmosphere in which the emulsified dispersion is sprayed, a gas obtained by heating air, nitrogen, carbon dioxide gas, combustion gas, or the like, in particular, various air currents heated to a temperature equal to or higher than the boiling point of the highest boiling solvent used is generally used. Sufficient quality can be obtained with a short treatment such as spray dryer, belt dryer or rotary kiln.

When the particle size distribution at the time of emulsification dispersion is wide and washing and drying processes are performed while maintaining the particle size distribution, the particle size distribution can be adjusted by classifying into a desired particle size distribution.
In the classification operation, the fine particle portion can be removed in the liquid by a cyclone, a decanter, centrifugation, or the like. Of course, the classification operation may be performed after obtaining the powder as a powder after drying. The unnecessary fine particles or coarse particles obtained can be returned to the kneading step and used for the formation of particles. At that time, fine particles or coarse particles may be wet.
The dispersant used is preferably removed from the obtained dispersion as much as possible, but it is preferable to carry out it simultaneously with the classification operation described above.

  By mixing the resulting dried toner powder with dissimilar particles such as release agent fine particles, charge control fine particles, fluidizing agent fine particles, and colorant fine particles, or by giving mechanical impact force to the mixed powder By immobilizing and fusing on the surface, it is possible to prevent detachment of the foreign particles from the surface of the resulting composite particle.

  Specific means include a method of applying an impact force to the mixture by blades rotating at high speed, a method of injecting and accelerating the mixture in a high-speed air stream, and causing particles or composite particles to collide with an appropriate collision plate, etc. is there. As equipment, Ong mill (manufactured by Hosokawa Micron Co., Ltd.), I-type mill (manufactured by Nippon Pneumatic Co., Ltd.) is modified to reduce the pulverization air pressure, hybridization system (manufactured by Nara Machinery Co., Ltd.), kryptron Examples include a system (manufactured by Kawasaki Heavy Industries, Ltd.) and an automatic mortar.

  As the colorant used in the toner, pigments and dyes conventionally used as toner colorants can be used. Specifically, carbon black, lamp black, iron black, ultramarine, nigrosine dye, Aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine 6C lake, calco oil blue, chrome yellow, quinacridone red, benzidine yellow, rose bengal and the like can be used alone or in combination.

  Further, if necessary, in order to give the toner particles magnetic properties, magnetic components such as iron oxides such as ferrite, magnetite and maghemite, metals such as iron, cobalt and nickel, or alloys of these with other metals. May be contained alone or in combination in the toner particles. Moreover, these components can also be used / used together as a colorant component.

The number average diameter of the colorant in the toner used in the present invention is desirably 0.5 μm or less, preferably 0.4 μm or less, more preferably 0.3 μm or less.
When the number average diameter of the colorant in the toner is larger than 0.5 μm, the dispersibility of the pigment does not reach a sufficient level, and preferable transparency may not be obtained.
A colorant having a fine particle diameter of less than 0.1 μm is sufficiently smaller than a half wavelength of visible light, and thus is considered not to adversely affect light reflection and absorption characteristics. Therefore, the colorant particles of less than 0.1 μm contribute to good color reproducibility and transparency of the OHP sheet having a fixed image. On the other hand, if there are many colorants having a particle size larger than 0.5 μm, the transmission of incident light is hindered or scattered, and the brightness and color of the projected image of the OHP sheet tend to decrease. There is.
Further, if there are many colorants having a particle size larger than 0.5 μm, the colorant is detached from the surface of the toner particles and easily causes various problems such as fogging, drum contamination, and poor cleaning. In particular, the colorant having a particle size larger than 0.7 μm is preferably 10% by number or less, more preferably 5% by number or less of the total colorant.
In addition, by adding a wetting liquid in advance with a part or all of the binder resin and kneading the colorant, the binder resin and the colorant are initially sufficiently adhered, In the toner production process, the colorant is dispersed more effectively in the toner particles, the dispersed particle diameter of the colorant is reduced, and better transparency can be obtained.

As the binder resin used for kneading in advance, the resins exemplified as the binder resin for toner can be used as they are, but are not limited thereto.
As a specific method for kneading the mixture of the binder resin and the colorant with the wetting liquid in advance, for example, the binder resin, the colorant and the wetting liquid are obtained after mixing with a blender such as a Henschel mixer. The obtained mixture is kneaded at a temperature lower than the melting temperature of the binder resin by a kneader such as a two-roll or three-roll to obtain a sample.

In addition, as the wetting liquid, a general one can be used in consideration of the solubility of the binder resin and the paintability with the colorant, but in particular, an organic solvent such as acetone, toluene, butanone, or water, It is preferable from the viewpoint of dispersibility of the colorant.
Among these, the use of water is more preferable from the viewpoint of environmental considerations and maintaining the dispersion stability of the colorant in the subsequent toner production process.
According to this manufacturing method, not only the particle diameter of the colorant particles contained in the obtained toner is reduced, but also the uniformity of the dispersion state of the particles is increased, so that the color reproducibility of the projected image by OHP is further improved. Get better.

In addition, as long as the configuration of the present invention is adopted, a release agent represented by wax can be contained in the toner together with the binder resin and the colorant.
Known release agents can be used, such as polyolefin wax (polyethylene wax, polypropylene wax, etc.); long chain hydrocarbons (paraffin wax, sasol wax, etc.); carbonyl group-containing wax, etc. .

  Of these, carbonyl group-containing waxes are preferred. Carbonyl group-containing waxes include polyalkanoic acid esters (carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18. -Octadecanediol distearate, etc.); polyalkanol esters (tristearyl trimellitic acid, distearyl maleate, etc.); polyalkanoic acid amides (ethylene diamine dibehenyl amide, etc.); polyalkylamides (trimellitic acid tristearyl amide, etc.) And dialkyl ketones (such as distearyl ketone).

  Among these carbonyl group-containing waxes, polyalkanoic acid esters are preferred. The melting point of these release agents is usually 40 to 160 ° C, preferably 50 to 120 ° C, more preferably 60 to 90 ° C. A wax having a melting point of less than 40 ° C. has an adverse effect on heat resistant storage stability, and a wax having a melting point of more than 160 ° C. tends to cause a cold offset when fixing at a low temperature. Further, the melt viscosity of the wax is preferably 5 to 1000 cps, more preferably 10 to 100 cps as a measured value at a temperature 20 ° C. higher than the melting point. Waxes exceeding 1000 cps have poor effects for improving hot offset resistance and low-temperature fixability. The content of the wax in the toner is usually 0 to 40% by weight, preferably 3 to 30% by weight.

In addition, a charge control agent may be contained in the toner as necessary in order to accelerate the toner charge amount and its rise. Here, since a color change occurs when a colored material is used as the charge control agent, a material that is colorless and close to white is preferable.
Any known charge control agent can be used. Examples include triphenylmethane dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkyls. Amide, phosphorus simple substance or compound, tungsten simple substance or compound, fluorine-based activator, salicylic acid metal salt, metal salt of salicylic acid derivative, and the like. Specifically, Bontron P-51 of a quaternary ammonium salt, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex, E-89 of a phenol condensate (above, Orient Chemical Co., Ltd.) Manufactured), TP-302, TP-415 of quaternary ammonium salt molybdenum complex (above, manufactured by Hodogaya Chemical Co., Ltd.), copy charge PSY VP2038 of quaternary ammonium salt, copy blue PR of triphenylmethane derivative, Quaternary ammonium salt copy charge NEG VP2036, copy charge NX VP434 (from Hoechst), LRA-901, boron complex LR-147 (Nihon Kalit Ltd), quinacridone, azo pigment, other sulfone Polymerization with functional groups such as acid groups, carboxyl groups, and quaternary ammonium salts Thing, and the like.

  In the present invention, the amount of charge control agent used is determined by the toner production method including the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method, and is uniquely limited. However, it is preferably used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the main charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, the flowability of the developer is reduced, and the image density is reduced. Incurs a decline. These charge control agents can be dissolved and dispersed after being melt-kneaded with a masterbatch and resin, or may be added when directly dissolving and dispersing in an organic solvent, or may be fixed on the toner surface after preparation of toner particles. Also good.

Further, when the toner composition is dispersed in the aqueous medium during the toner production process, resin fine particles mainly for stabilizing the dispersion may be added.
The resin fine particles used may be any resin that can form an aqueous dispersion, and may be a thermoplastic resin or a thermosetting resin. For example, vinyl resins, polyurethane resins, epoxy resins, polyester resins, Examples thereof include polyamide resin, polyimide resin, silicon resin, phenol resin, melamine resin, urea resin, aniline resin, ionomer resin, and polycarbonate resin. As the resin fine particles, two or more of the above resins may be used in combination. Of these, vinyl resins, polyurethane resins, epoxy resins, polyester resins, and combinations thereof are preferred because an aqueous dispersion of fine spherical resin particles is easily obtained.

  The vinyl resin is a polymer obtained by homopolymerization or copolymerization of a vinyl monomer, such as a styrene- (meth) acrylate resin, a styrene-butadiene copolymer, a (meth) acrylic acid-acrylate polymer, Examples include, but are not limited to, styrene-acrylonitrile copolymers, styrene-maleic anhydride copolymers, styrene- (meth) acrylic acid copolymers, and the like.

Further, inorganic fine particles can be preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles.
The primary particle diameter of the inorganic fine particles is preferably 5 μm to 2 μm, and particularly preferably 5 μm to 500 μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The proportion of the inorganic fine particles used is preferably 0.01 to 5% by weight of the toner, and particularly preferably 0.01 to 2.0% by weight. Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.
In addition, polymer fine particles such as polystyrene obtained by soap-free emulsion polymerization, suspension polymerization and dispersion polymerization, methacrylic acid ester and acrylic acid ester copolymer, polycondensation system such as silicone, benzoguanamine and nylon, thermosetting resin And polymer particles.

  Such a fluidizing agent can be surface-treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, silane coupling agents, silylating agents, silane coupling agents having an alkyl fluoride group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils and the like are preferable surface treatment agents. .

  Examples of the cleaning property improver for removing the developer after transfer remaining on the photoreceptor or the primary transfer medium include fatty acid metal salts such as zinc stearate, calcium stearate and stearic acid, such as polymethyl methacrylate fine particles, polystyrene. Examples thereof include fine polymer particles produced by soap-free emulsion polymerization of fine particles and the like. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.

  By using these toners, a high-quality toner image having excellent development stability can be formed as described above. However, the toner that is not transferred to the transfer medium or intermediate transfer medium by the transfer device and remains on the image carrier is difficult to remove by the cleaning device due to its fineness and good rolling properties. May end up. In order to completely remove the toner from the image carrier, it is necessary to strongly press a toner removing member such as a cleaning blade against the image carrier. Such a load not only shortens the life of the image carrier and the cleaning device, but also uses extra energy.

  When the load on the image carrier is reduced, the toner on the image carrier and the small-diameter carrier are insufficiently removed, and these damage the surface of the image carrier when passing through the cleaning blade of the cleaning device. It becomes a factor which fluctuates the performance of the forming apparatus.

  As described above, the image forming apparatus of the present invention has an excellent tolerance for fluctuations in the surface state of the image carrier, particularly the presence of a low-resistance portion, and highly suppresses fluctuations in charging performance to the image carrier. Because of the configuration, when used in combination with the toner having the above configuration, an extremely high quality image can be stably obtained over a long period of time.

In addition, the image forming apparatus of the present invention can be applied not only to the use of the toner having a configuration suitable for obtaining a high quality image as described above, but also to an irregular shaped toner by a pulverization method, and the life of the apparatus. Needless to say, it will be greatly extended.
As a material constituting such a pulverized toner, those usually used as an electrophotographic toner can be applied without particular limitation.

  Examples of general binder resins used in the above toner include styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene, and homopolymers of substitution products thereof; styrene / p-chlorostyrene copolymer. Styrene / propylene copolymer, styrene / vinyl toluene copolymer, styrene / vinyl naphthalene copolymer, styrene / methyl acrylate copolymer, styrene / ethyl acrylate copolymer, styrene / butyl acrylate copolymer Styrene / octyl acrylate copolymer, styrene / methyl methacrylate copolymer, styrene / ethyl methacrylate copolymer, styrene / butyl methacrylate copolymer, styrene / α-chloromethyl methacrylate copolymer, styrene / Acrylonitrile copolymer, styrene / vinyl methyl ketone copolymer Styrene copolymers such as styrene / butadiene copolymer, styrene / isoprene copolymer, styrene / maleic acid copolymer; polymethyl acrylate, polybutyl acrylate, polymethyl methacrylate, polybutyl methacrylate, etc. Acrylic ester monopolymers and copolymers thereof; polyvinyl derivatives such as polyvinyl chloride and polyvinyl acetate; polyester polymers, polyurethane polymers, polyamide polymers, polyimide polymers, polyol polymers An epoxy polymer, a terpene polymer, an aliphatic or alicyclic hydrocarbon resin, an aromatic petroleum resin, and the like can be used, and these can be used alone or in combination, but are not particularly limited thereto. Among these, at least one selected from styrene-acrylic copolymer resins, polyester resins, and polyol resins is more preferable from the viewpoint of electrical characteristics, cost, and the like. Furthermore, it is more preferable to use a polyester-based resin and / or a polyol-based resin as having good fixing characteristics.

For the reasons described above, the same resin component as the binder resin of the toner contained in the coating layer of the charging member includes a linear polyester resin composition, a linear polyol resin composition, and a linear styrene acrylic resin. At least one of the compositions or these cross-linked products can be preferably used.
In the pulverized toner, together with these resin components, the colorant component, wax component, charge control component, and the like as described above are premixed as necessary, and then kneaded at a temperature close to the melting temperature of the resin component, and then cooled. Thereafter, a toner may be prepared through a pulverizing and classifying step, and the above-mentioned external additive components may be appropriately added and mixed as necessary.

(Image carrier refresh mode)
Next, the image carrier refresh mode in the image forming apparatus of the present invention will be described.
FIG. 8 shows an example of the control system of the image forming apparatus of the present invention.
The control unit includes a central processing unit (CPU) that is a control device, a memory (ROM, RAM, nonvolatile RAM, etc.) that stores various control programs and control data, an input / output device (not shown), a clock, a timer, It consists of an image forming number counter, various control circuits, etc., setting information input from the operation panel, detection information of external environment detection means (temperature sensor, humidity sensor), detection information of other various sensors, and a control program, In accordance with the control data, each part of the image forming apparatus (for example, an exposure device driving unit, an image carrier driving unit, a charging device driving unit, a developing device driving unit, a transfer unit driving unit, a paper feeding, a conveyance driving unit, a fixing device driving unit, A supply member driving unit of the protective layer forming apparatus) and the series of image forming operations described above.
The control program of the control unit incorporates a program for executing the image carrier refresh mode.
Note that a temperature sensor and a humidity sensor, which are external environment detection means, are attached to the main body of the image forming apparatus shown in FIG.

In the image forming apparatus of the present invention, the control unit shown in FIG. 8 is configured to execute an image carrier refresh mode for removing the protective agent on the surface of the photoconductor during non-image formation. Control means for executing a refresh mode.
The control unit normally executes the image carrier refresh mode for each predetermined number of sheets based on the count information from the image forming number counter at the time of non-image forming, but the temperature and humidity of the external environment are equal to or higher than the predetermined temperature and humidity. The image carrier refresh mode is also executed when.

The image carrier refresh mode in the present invention is a temperature sensor for detecting the temperature and humidity of the external environment installed in the image forming apparatus main body, and the temperature and humidity input by the humidity sensor are equal to or higher than a predetermined temperature and humidity. In this mode, after passing a predetermined number of sheets, the photosensitive member as an image carrier and a protective agent supply member (for example, a brush roller) for supplying the image carrier protective agent are idled during non-image formation. .
The filming material on the surface of the photoreceptor can be removed by executing the image carrier refresh mode and sliding the surface of the photoreceptor with a brush roller. By executing this image carrier refresh mode at the time of non-image formation, contamination of the photoconductor can be prevented over a long period of time.

In the image forming apparatus of the present invention, as an image carrier protecting agent, a lubricant obtained by adding boron nitride to a solid lubricant mainly composed of zinc stearate, which is hardly deteriorated by charging and has excellent cleaning properties. Therefore, unlike the system using only zinc stearate as a lubricant, it is not necessary to control to reduce the AC charging current of the charging member in the image carrier refresh mode. That is, the photosensitive member and the protective agent supply member (brush roller) can be rotated at a predetermined number of rotations regardless of whether or not the charging member is charged.
In addition, the relationship between the temperature and humidity of the external environment, the interval at which the image carrier refresh mode is executed, and the rotational speed of idling may be set as appropriate depending on the model configuration of the image forming apparatus.
That is, in the image carrier refresh mode, the rotational speed of the idle rotation of the photoreceptor and the protective agent supply member (brush roller) depends on the toner and photoreceptor conditions of each image forming apparatus and the blades of the cleaning apparatus and the protective layer forming mechanism. The optimum conditions are appropriately set according to the contact conditions and the like, and the optimum conditions are preliminarily tabulated and stored in a ROM, nonvolatile RAM or the like of the memory, and control based on the tabulated control data is performed.

Hereinafter, specific examples of the present invention will be described.
The table of FIG. 9 shows an embodiment of the image forming apparatus according to the present invention together with a comparative example.
As an image forming apparatus, the image carrier protecting agent of the present invention was supplied from a protective layer forming apparatus supplying zinc stearate in an image forming unit of imgio MP C5000 manufactured by Ricoh.
The technology of Patent Document 4 is used for the mechanism for pressurizing zinc stearate in imgio MP C5000 manufactured by Ricoh, and the pressure is almost constant over time.

A 2000-sheet continuous paper feeding test was performed on an A4 size original including a vertical belt portion with an image area ratio of 100%, and the photoreceptor contamination and the charging member contamination were visually observed. In the image carrier refresh mode, the photoconductor was rotated 20 times every time 100 images were formed.
Using a worn cleaning blade, the experiment was conducted under accelerated conditions where the charging member is easily contaminated.
Moreover, the external environment was implemented in two environments, ie, an environment with a temperature of 32 ° C. and a humidity of 80%, and a laboratory environment with room temperature and normal humidity.

[Example 1]
When using an image carrier protective agent that is compression molded by mixing a fatty acid metal salt and an inorganic lubricant at a weight ratio of 8 to 2, zinc stearate (manufactured by NOF Corporation) is used as the fatty acid metal salt. Boron nitride (manufactured by Momentive Performance Materials) was used as the agent. The test was performed in a laboratory environment without an image carrier refresh mode and when the external environment was at a temperature of 32 ° C. and a humidity of 80% and had an image carrier refresh mode.

[Example 2]
When the image carrier protective agent is a compression molded product of a fatty acid metal salt and an inorganic lubricant mixed at a weight ratio of 8 to 2. Calcium stearate (manufactured by Wako Pure Chemical Industries) was used as the fatty acid metal salt, and boron nitride (manufactured by Momentive Performance Materials) was used as the inorganic lubricant. The test was performed in a laboratory environment without an image carrier refresh mode and when the external environment was at a temperature of 32 ° C. and a humidity of 80% and had an image carrier refresh mode.

[Example 3]
When the image carrier protective agent is a compression molded product of a fatty acid metal salt and an inorganic lubricant mixed at a weight ratio of 8 to 2. Zinc stearate (manufactured by Nippon Oil & Fats) was used as the fatty acid metal salt, and mica (manufactured by Shiseido) was used as the inorganic lubricant. The test was performed in a laboratory environment without an image carrier refresh mode and when the external environment was at a temperature of 32 ° C. and a humidity of 80% and had an image carrier refresh mode.

[Comparative Example 1]
When a fatty acid metal salt is melted, poured into a mold, cooled and molded as an image carrier protective agent. As the fatty acid metal salt, zinc stearate (manufactured by NOF Corporation) was used. All the image carrier protecting agents currently used in image forming apparatuses are produced by this method. When the external environment was 32 ° C. and the humidity was 80%, and in the laboratory environment, the test was performed without the image carrier refresh mode.

[Comparative Example 2]
When a fatty acid metal salt is melted, poured into a mold, cooled and molded as an image carrier protective agent. As the fatty acid metal salt, zinc stearate (manufactured by NOF Corporation) was used. All the image carrier protecting agents currently used in image forming apparatuses are produced by this method. In the case where the external environment was a temperature of 32 ° C. and the humidity was 80%, and in the laboratory environment, the image carrier refresh mode was performed.

[Comparative Example 3]
When the image carrier protective agent is a compression molded product of a fatty acid metal salt and an inorganic lubricant mixed at a weight ratio of 8 to 2. Zinc stearate (manufactured by Nippon Oil & Fats) was used as the fatty acid metal salt, and boron nitride (manufactured by Momentive Performance Materials) was used as the inorganic lubricant. When the external environment was 32 ° C. and the humidity was 80%, and in the laboratory environment, the test was performed without the image carrier refresh mode.

[Comparative Example 4]
When the image carrier protective agent is a compression molded product of a fatty acid metal salt and an inorganic lubricant mixed at a weight ratio of 8 to 2. Calcium stearate (manufactured by Wako Pure Chemical Industries) was used as the fatty acid metal salt, and boron nitride (manufactured by Momentive Performance Materials) was used as the inorganic lubricant. When the external environment was 32 ° C. and the humidity was 80%, and in the laboratory environment, the test was performed without the image carrier refresh mode.

[Comparative Example 5]
When the image carrier protective agent is a compression molded product of a fatty acid metal salt and an inorganic lubricant mixed at a weight ratio of 8 to 2. Zinc stearate (manufactured by Nippon Oil & Fats) was used as the fatty acid metal salt, and mica (manufactured by Shiseido) was used as the inorganic lubricant. When the external environment was 32 ° C. and the humidity was 80%, and in the laboratory environment, the test was performed without the image carrier refresh mode.
The evaluation results of the above examples and comparative examples are also displayed in the table of FIG.

The image forming apparatus of the present invention described above can suppress filming on the image carrier for the following reasons.
An image carrier protective agent is applied to the image carrier of the electrophotographic image forming apparatus in order to protect the image carrier from charging and cleaning hazards.
However, as a protective agent, the fatty acid metal salt has reduced lubricity due to the effect of charging, and in the cleaning member, toner and protective agent slip through and adhere to the charging member, causing charging member contamination. .
Therefore, by adding an inorganic lubricant, it is possible to assist lubricity, prevent the toner and the protective agent from slipping through, and reduce the amount of fatty acid metal salt flying to the charging member.
At present, a protective agent using a fatty acid metal salt typified by zinc stearate as a main raw material is generally used in many color machines. This protective agent is molded and solidified by melting a fatty acid metal salt as a raw material and pouring it into a mold.
On the other hand, in a protective agent in which an inorganic lubricant is added to a fatty acid metal salt, when the raw material is melted and molded and solidified, it becomes a very hard solid block and can be scraped off with a supply member such as a brush. Therefore, photoconductor contamination occurs. This is considered because the inorganic lubricant plays the role of a filler. Therefore, a protective agent obtained by adding an inorganic lubricant to a fatty acid metal salt is generally produced by compression molding.

The protective agent containing boron nitride has a high adhesive force to the image carrier of the inorganic lubricant itself, and when image formation is performed in a high temperature and high humidity environment, the protective agent is deposited on the image carrier, Filming occurs on the carrier. As a result, defective images and image blur due to insufficient charging occur.
Therefore, an image carrier protective agent containing a fatty acid metal salt and an inorganic lubricant has an image carrier refresh mode for removing filming substances on the surface of the image carrier, and detects the temperature and humidity of the external environment. By executing the image carrier refresh mode at a time other than the time of image formation based on the result of the means, an image can be stably output over time regardless of the external environment.

In the present invention, as in Examples 1 to 3, in the image carrier protective agent containing a fatty acid metal salt and an inorganic lubricant, the image carrier is carried out by executing the image carrier refresh mode at a predetermined temperature and humidity. Since the surface of the body is rubbed by the supply member, filming on the surface of the image carrier can be removed, and an image can be output stably over time.
However, as in Comparative Examples 3 to 5, when the image carrier refresh mode is not executed at a predetermined temperature and humidity, an abnormal image is output, and the image cannot be output stably over time.

In the present invention, from comparison between Example 1 and Example 2 and Comparative Example 3 and Comparative Example 4, better photoconductor protection is obtained when stearic acid is used as the fatty acid metal salt. Of the higher fatty acids, stearic acid is the cheapest, and among them, zinc salts are very stable substances with excellent hydrophobicity.
Further, in the present invention, from the comparison between Example 1 and Example 3 and Comparative Example 3 and Comparative Example 5, the use of boron nitride as the inorganic lubricant can provide a better effect of preventing charging member contamination.

  In the present invention, the image carrier protecting agent exhibits a protective effect by adhering to the surface of the image carrier and forming a film, and thus is relatively easily plastically deformed. Accordingly, when an attempt is made to form a protective layer by directly pressing the bulky image carrier protective agent component onto the surface of the image carrier, not only the supply becomes excessive and the protective layer formation efficiency is not good, but also the protective layer becomes multilayered and static. Since it may become a factor that impedes light transmission in an exposure process such as when forming an electrostatic latent image, the types of image carrier protecting agents that can be used are limited. On the other hand, the protective layer forming apparatus is configured to have a protective agent supply member (brush roller) made of a brush-like member, and by interposing the protective agent supply member between the image carrier protective agent and the image carrier, Even when a soft image carrier protective agent is used, the protective agent can be evenly supplied to the surface of the image carrier. When the protective layer forming apparatus is provided with a layer forming member (blade) that presses the image carrier protective agent to form a film, the layer forming member may also serve as a cleaning member, but the protective layer is more reliably formed. For this purpose, it is preferable to remove in advance a residue mainly composed of toner on the image carrier by a cleaning member so that the residue does not enter the protective layer.

In the present invention, as shown in FIG. 6, by configuring the process cartridge 11 using the protective layer forming apparatus 2 having the image carrier protecting agent, the process cartridge replacement interval can be set extremely long. This makes it possible to reduce running costs and greatly reduce the amount of waste.
Further, since the component of the image carrier protecting agent of the present invention does not substantially contain a metal component, the charging member disposed in contact with or close to the image carrier is contaminated with a metal oxide or the like. In addition, the change with time of the charging device can be reduced. For this reason, it becomes easy to reuse process cartridge components such as an image carrier and a charging member, and the amount of waste can be further reduced.

1 (1Y, 1M, 1C, 1K): image carrier (photosensitive drum)
2: Protection layer forming device 3: Charging device (charging roller)
4: Cleaning device (cleaning mechanism)
5: Development device 6: Primary transfer device (transfer means)
7: Intermediate transfer member (or transfer medium)
8: exposure device 9: belt cleaning device 10: image forming unit 11: process cartridge 12: secondary transfer device 13: transport device 14: fixing device 15: transport device 16: paper discharge roller 17: paper discharge tray 21: image carrier Body protective agent 22: Protective agent supply member 23: Pressurizing force applying mechanism 24: Protective layer forming mechanism 24a: Blade-like member (blade)
24b: pressing member 25: protective agent support member (holder)
41: Cleaning member (cleaning blade)
42: cleaning pressing member 51: developing roller 52, 53: stirring and conveying screw 100: image forming apparatus 110: image forming apparatus main body (printer unit)
120: Document reading unit (scanner unit)
130: Automatic document feeder (ADF)
200: paper feed unit 201a to 201d: paper feed cassette 202: paper feed roller 203: separation roller 204, 205, 206: transport roller 207: registration roller 210: transport device for both sides L: exposure

Japanese Patent Publication No.51-22380 JP 2006-350240 A JP 2001-305907 A JP 2007-293240 A JP 2007-65100 A JP 2005-30201 A JP 2006-154212 A

Claims (14)

An image carrier;
A charging device having a charging member arranged close to or in contact with the image carrier and applying a charging bias voltage to the charging member to uniformly charge the surface of the image carrier;
An exposure device that exposes the surface of the charged image carrier based on image data and writes a latent image; and
A developing device that supplies toner to the latent image formed on the surface of the image carrier to visualize the latent image;
A transfer device for transferring a visible image on the surface of the image carrier directly to a transfer medium or via an intermediate transfer member;
A cleaning device for cleaning the surface of the image carrier after transfer;
A protective layer forming apparatus for applying or adhering an image carrier protective agent to the surface of the image carrier;
In an image forming apparatus comprising:
The protective layer forming apparatus comprises an image carrier protective agent containing at least a fatty acid metal salt and an inorganic lubricant, and a protective agent supplying member for applying or adhering the image carrier protective agent to the surface of the image carrier,
In addition, the image forming apparatus main body includes detection means for detecting the temperature and humidity of the external environment,
An image forming apparatus comprising: a control unit that executes an image carrier refresh mode during non-image formation based on a detection result of a detection unit that detects temperature and humidity of the external environment. The image forming apparatus according to claim 1.
In the image carrier refresh mode, the image carrier is idled at a predetermined number of rotations regardless of whether the charging member is charged or not. The image forming apparatus according to claim 1, wherein
In the image carrier refresh mode, the image carrier and the protective agent supply member are rotated at a predetermined number of revolutions. The image forming apparatus according to claim 1,
The image forming apparatus according to claim 1, wherein the detecting means for detecting the temperature and humidity of the external environment is a temperature sensor and a humidity sensor attached to the image forming apparatus main body. In the image forming apparatus according to any one of claims 1 to 4,
The image forming apparatus, wherein the fatty acid metal salt contained in the image carrier protecting agent is zinc stearate. The image forming apparatus according to claim 1,
An image forming apparatus, wherein the inorganic lubricant contained in the image carrier protecting agent is boron nitride. The image forming apparatus according to claim 1,
The protective layer forming apparatus supplies the image carrier protective agent to the surface of the image carrier through a protective agent supply member made of a rotating brush-like member. The image forming apparatus according to claim 1,
An image forming apparatus comprising: a layer forming member that presses the image carrier protecting agent supplied to the surface of the image carrier to form a film. The image forming apparatus according to claim 8.
The image forming apparatus, wherein the layer forming member is a blade-like member. The image forming apparatus according to claim 1,
An image forming apparatus, wherein the image carrier is a photoconductor. The image forming apparatus according to claim 1,
The circularity SR of the toner is
An image forming apparatus, wherein the circularity SR is 0.93 to 1.00 when the circularity SR = peripheral length of a circle having the same area as the particle projection area / perimeter length of the particle projection image. The image forming apparatus according to claim 1,
An image forming apparatus, wherein a ratio (D4 / D1) of a weight average diameter (D4) and a number average diameter (D1) of the toner is 1.00 to 1.40. A process cartridge for use in the image forming apparatus according to claim 1,
At least an image carrier through which a toner image is carried; and
A protective layer forming device for applying or adhering an image carrier protective agent to the surface of the image carrier after the toner image is transferred to a transfer medium;
A process cartridge which is detachably mounted on an image forming apparatus main body. The process cartridge according to claim 13, wherein
A process cartridge comprising a charging device, a developing device, and a cleaning device in addition to the image carrier and the protective layer forming device.

Images