JP2017151268A - Toner, toner storage unit, image forming apparatus, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize high image density without causing abnormal images due to filming by an external additive on a photoconductor even when repeatedly used not only at room temperature and normal humidity but also under low temperature and low humidity environment for a long time. To provide toner that can be secured. A toner containing toner base particles having a binder resin and at least two kinds of inorganic fine particles, wherein the inorganic fine particles are 1.0% by mass to 3.5% with respect to the toner base particles. When the toner is made to collide by using a vacuum disperser by a vacuum dispersion type image analysis method in which the toner is collided with the substrate, the free number of the inorganic fine particles dispersed in the substrate made of carbon tape is the toner. 10 or less per particle, the number of free inorganic fine particles dispersed in the substrate made of mica is 200 to 1,800 per particle of the toner, and 350 nm or more dispersed in the substrate made of mica. The toner is characterized in that the number of released inorganic fine particles of 500 nm or less is 50 or less per particle of the toner. [Selection diagram] None

Description

  The present invention relates to a toner, a toner storage unit, an image forming apparatus, and an image forming method.

Conventionally, toner used for image formation such as electrophotography has externally added inorganic fine particles to toner base particles in order to ensure transportability and chargeability in the image forming apparatus.
However, if the inorganic fine particles externally added to the toner are embedded in the toner base particles due to stress with the conveying member during toner conveyance in the developing device, the toner fluidity is impaired, and toner replenishment property, Developability and chargeability deteriorate with time. Further, the image density is lowered during long-term repeated use.
In addition, if the external additive is liberated from the toner during the development, not only does the toner chargeability and flowability decrease, the image density decreases and the development becomes clogged, but the toner adheres to the developing roller and is fixed. The amount of toner drawn up at the location where the toner is fixed decreases, and an abnormal image is generated.
In addition, when the external additive is released from the toner at the time of transfer to the photosensitive member or the intermediate transfer belt, the external additive forms a film on the entire photosensitive member or the intermediate transfer belt. Optical and electrical characteristics are degraded and abnormal images are likely to be generated. The image forming apparatus is generally provided with a cleaning mechanism for removing filming substances deposited on the photosensitive member and the intermediate transfer belt. However, the cleaning function is deteriorated particularly in a low-temperature and low-humidity environment. .
On the other hand, it is difficult to completely suppress the liberation of toner external additives during image formation. In addition, when an appropriate amount of external additive is supplied onto the photoconductor or intermediate transfer belt, the supplied external additive is preferable for cleaning the surface of the photoconductor or intermediate transfer belt.

In recent years, in order to reduce the particle size and spheroidization of the toner, the toner is granulated in a liquid, including a toner produced by a suspension polymerization method, an emulsion polymerization method, a dispersion polymerization method, or the like. Many methods for manufacturing the same In particular, in the case of a toner having a small particle diameter, the surface area of the toner base particles is relatively large. Therefore, in order to ensure fluidity, it is necessary to increase the amount of the external additive added. The liberation of the external additive is likely to occur, and there is a problem that filming of the external additive increases. Therefore, there is a demand for a toner that does not release the external additive until the toner is put into the developing device, and that is released from an appropriate amount of toner when the toner is transferred to the photoreceptor or the intermediate transfer belt.
As described above, it is very important to consider how the external additive is released from the toner in order to continuously form a high-quality image. As a method for determining the ease of release of the external additive from the toner, for example, ultrasonic vibration is applied to the toner dispersion liquid, and the external additive released from the weight change of the toner after the external additive released from the toner is removed. A wet method for obtaining the ratio of the agent is disclosed (for example, see Patent Documents 1 and 2).

However, although the wet methods disclosed in Patent Documents 1 and 2 can roughly determine the ease of liberation of the external additive, the measurement variation is very large, and the measured value and the external additive from the toner are different. In many cases, there was no correlation with the degree of filming of the external additive on the photoreceptor due to liberation. In addition, since it was not known at all how the external additive was released, it was not known whether the defect was due to the release of the external additive. In fact, despite the fact that the same toner is used, it is impossible to explain that the occurrence of a problem changes simply by changing the members such as the carrier, the developing roller, the photoconductor, and the intermediate transfer belt. No stable image could be obtained.
Therefore, the present invention does not generate abnormal images due to filming due to external additives on the photosensitive member even when used repeatedly over a long period of time, not only at normal temperature and humidity, but particularly in a low temperature and low humidity environment. An object of the present invention is to provide a toner whose density can be secured stably.

Means for solving the above-described problems are the following toners. That is,
The toner of the present invention is a toner containing toner base particles having a binder resin and at least two kinds of inorganic fine particles,
Containing 1.0 to 3.5% by weight of the inorganic fine particles with respect to the toner base particles,
When the toner is collided using a vacuum disperser by a vacuum dispersion type image analysis method in which the toner collides with the substrate,
The number of liberated inorganic fine particles dispersed on the substrate made of carbon tape is 10 or less per one toner particle;
The number of liberated inorganic fine particles dispersed on the substrate made of mica is 200 to 1,800 per one toner particle,
The number of liberated inorganic fine particles of 350 nm or more and 500 nm or less dispersed on the substrate made of the mica is 50 or less per toner particle.

  According to the present invention, not only normal temperature and normal humidity, but also an abnormal image caused by filming due to an external additive on the photoreceptor does not occur even when used repeatedly over a long period of time particularly in a low temperature and low humidity environment, and a high image density Can be provided stably.

FIG. 1A is an example diagram for explaining a vacuum dispersion type image analysis method in which toner collides with a substrate. FIG. 1B is an example diagram for explaining a vacuum dispersion type image analysis method in which toner collides with a substrate. FIG. 1C is an example diagram for explaining a vacuum dispersion type image analysis method in which toner collides with a substrate. FIG. 1D is an example diagram for explaining a vacuum dispersion type image analysis method in which toner collides with a substrate. FIG. 1E is an example diagram for explaining a vacuum dispersion type image analysis method in which toner collides with a substrate. FIG. 2 is an example diagram showing a scanning electron microscope (SEM) image of the toner on the carbon tape. FIG. 3 is an example diagram showing a scanning electron microscope (SEM) image of toner on mica. FIG. 4 is a schematic configuration diagram showing an example of the image forming apparatus of the present invention. FIG. 5 is a schematic configuration diagram showing an example of the image forming apparatus of the present invention. FIG. 6 is a schematic configuration diagram showing an example of a tandem color image forming apparatus which is another image forming apparatus of the present invention. FIG. 7 is a schematic configuration diagram showing an example of a tandem color image forming apparatus which is another image forming apparatus of the present invention. FIG. 8 is a schematic configuration diagram showing an example of a tandem type color image forming apparatus which is another image forming apparatus of the present invention.

(toner)
The toner of the present invention contains toner base particles having a binder resin and at least two kinds of inorganic fine particles.
The inorganic fine particles are contained in an amount of 1.0% by mass to 3.5% by mass with respect to the toner base particles.
The toner of the present invention is preferably obtained by externally adding the inorganic fine particles to the toner base particles from the viewpoint of imparting fluidity.
When the toner is collided using a vacuum disperser by a vacuum dispersion type image analysis method in which the toner collides with the substrate,
The number of liberated inorganic fine particles dispersed on the substrate made of carbon tape is 10 or less per toner particle, and the number of liberated inorganic fine particles dispersed on the substrate made of mica is 200 per toner particle. The number of inorganic fine particles of 350 nm to 500 nm dispersed on the substrate made of mica is 50 or less per one toner particle.

The present inventors have found that the toner satisfying the above conditions is not only at normal temperature and humidity, but also abnormal images caused by filming due to external additives on the photoreceptor even when used repeatedly over a long period of time particularly in a low temperature and low humidity environment. It was found that the toner can be stably secured with a high image density.
Based on the recognition that the ease of liberation of the external additive from the toner greatly contributes to the occurrence of filming, the inventors of the present invention have focused their research on the characteristics of the external additive. Thus, it has been found that liberation of the external additive from the toner basically occurs when the toner collides with something. Further, it has been found that the liberation of the external additive from the toner changes depending on the hardness of the substrate on which the toner collides.

When a toner is collided with a substrate made of carbon tape using a vacuum disperser using a vacuum dispersion type image analysis method, the free number of inorganic fine particles dispersed on the carbon tape is determined by setting the toner in the image forming apparatus. It can be considered that this corresponds to the free state of the inorganic fine particles before the toner is applied, that is, when no stress is applied to the toner. If the number of inorganic fine particles per toner particle on the carbon tape is 10 or more, fluidity cannot be secured within the development, and appropriate chargeability cannot be obtained, resulting in a background stain image due to toner scattering. To do. In addition, when the toner is made to collide with the substrate made of mica using the vacuum disperser, the free number of inorganic fine particles dispersed on the mica is the free state of the inorganic fine particles when the toner hits a hard material. It turns out that it can be regarded as equivalent. When the number of free inorganic fine particles dispersed on the mica is 200 or less per toner particle, the embedding of the inorganic fine particles in the toner base becomes remarkable, and toner agglomerates to generate a black spot image. Density unevenness occurs. Further, when the number is 1,800 or more, filming on the photoconductor increases, and a white spot image due to the filming portion is generated. The number of liberated inorganic fine particles dispersed on the mica is preferably 200 to 1,800, more preferably 300 to 600 per toner particle.
Further, the number of liberated inorganic fine particles of 350 nm or more and 500 nm or less dispersed on the substrate made of the mica is 50 or less per one toner particle. In the case where the number of liberated inorganic fine particles of 350 nm or more and 500 nm or less is 50 or more per toner particle, the loose coarse inorganic fine particles damage the photoconductor, and an abnormal image such as white spots occurs.

<Vacuum dispersion type image analysis method>
A method of causing the toner to collide with the substrate surface in the toner evaluation method of the present invention will be described with reference to FIGS. 1A to 1E.
A toner sample 81 is placed on the top of the disperser (see FIG. 1A), the inside of the disperser is depressurized to 10 kPa (see FIG. 1B) by the vacuum pump 83 (see FIG. 1B), and then a gap is formed on the top of the disperser. The toner sample 81 is sucked into the disperser (see FIG. 1C). After being left for 1 minute (see FIG. 1D), the inside of the disperser is brought to normal pressure (see FIG. 1E), and the substrate (pin stub) 82 is taken out.
In the toner evaluation method of the present invention, the toner is introduced together with a very small amount of air from the upper part of the disperser. The toner hits the substrate linearly at high speed.
On the substrate on which the toner collides, there are provided at least one place having adhesiveness and one place harder than the place having adhesiveness. The toner is captured at the sticky portion. When the toner collides with a part having an adhesive, fine particles may be released from the toner base particles, but the toner base particles need to be attached to the part having adhesiveness. For this reason, the material of the adhesive part is not particularly limited as long as the toner base particles can be reliably attached, and can be appropriately selected according to the purpose. In consideration of observation with a scanning electron microscope (SEM), it is preferable to use a carbon tape for SEM observation that generates less gas and can reliably capture complement particles.
A portion harder than the portion having adhesiveness has no adhesiveness, and therefore, most of the toner base particles are not fixed on the hard portion. However, the fine particles adhering to the toner base particles remain on a hard portion due to electrostatic force, intermolecular force, and the like because of their small size. As a material of the harder portion than the sticky portion, a material used in a portion where the toner may collide in the image forming apparatus may be appropriately selected. For example, a carrier coat film, a developing roller, a photoreceptor, an intermediate transfer member (belt, roller), a cleaning blade, and the like can be given. Where the material is harder than the part having adhesiveness, the material itself may be used, but if it is not a smooth material, the same material as the surface in contact with the toner is made into a flat plate, a sheet, or a coating, It may be provided on the substrate surface.

When the toner is evaluated, it is preferable to use a toner sample having a number average particle diameter in the range of 0.5 μm to 200 μm as a toner sample to be put into the disperser. Moreover, it is preferably 1 μm to 100 μm, more preferably 2 μm to 50 μm. This is because when the number average particle diameter of the toner sample put into the disperser is within the above range, an accurate measurement result can be obtained in evaluating filming of the external additive.
In the decompression space in the toner evaluation method of the present invention, the inner diameter of the disperser is preferably 50 mm to 200 mm, and more preferably 70 mm to 150 mm, considering pressure resistance and the spread of particles to be introduced. The height of the decompression space is preferably 75 mm to 300 mm, and more preferably 100 mm to 260 mm. If the height of the decompression space is 75 mm or more, the dispersion of particles is uniform, and if the height is 260 mm or less, the space can be decompressed in a short time, and a large vacuum pump is unnecessary.
In the toner evaluation method of the present invention, the degree of vacuum in the reduced pressure space is preferably 20 kPa or less, and more preferably 5 kPa to 15 kPa. When the degree of vacuum in the decompression space is 20 kPa or less, it is possible to prevent the problem that the toner particles thrown into the decompression space are subjected to air resistance and the energy colliding with the substrate is weakened.
As a disperser used for evaluating the toner of the present invention, a disperser NEBULA 1 (manufactured by Phenom-World) is preferable because of excellent handling and dispersion reproducibility.

The density (A (number / mm ² )) of toner particles per unit area of the toner collided on the substrate can be obtained from the number of toner base particles of toner adhering to a sticky portion. Even if the inorganic fine particles are released from the toner adhering to the sticky part, as described above, the number average particle size of the inorganic fine particles is overwhelmingly small with respect to the toner. Only the toner can be determined. Further, A ′ / A was calculated from the density (A ′ (number / mm ² )) of the inorganic fine particles released from the toner adhering to the sticky part, and the toner colliding with the sticky part collided. At this time, the number of inorganic fine particles released from one toner particle can be calculated. The quality of the toner can be determined by the value of A ′ / A.
Further, the number B / A of inorganic fine particles released from one toner is calculated from the density (B (number / mm ² )) of the inorganic fine particles adhering to a place harder than the sticky place. The quality of the toner can be determined by the value.
Since it is difficult to measure the number of toner particles and the number of inorganic fine particles by using optical means, it is performed using a scanning electron microscope (SEM).

In SEM, since the shape of each inorganic fine particle is known, not only the particle size of the inorganic fine particle but also the particle size parameters such as circularity, convexity, and aspect ratio can be obtained. Therefore, for the inorganic fine particles attached to a harder place than the place having adhesiveness, the density of inorganic fine particles having a specific particle size parameter (C (pieces / mm ² )) is obtained, and C / A is calculated. The quality of the toner can be determined by the value of C / A.
Since the inorganic fine particles adhering to the toner are often agglomerated and there are cases where a plurality of types of inorganic fine particles are adhering, the C / A is calculated from the density of the inorganic fine particles having a specific particle diameter. The quality of the toner can be determined based on the value of C / A.

In this invention, the location which has adhesiveness is made into a carbon tape, and a location harder than it is made into mica.
Specifically, SEM carbon double-sided tape E3605 (EM Japan) is attached to the surface of a φ25 × 8 aluminum pins stub (EM Japan), and mica punched out to φ10 is attached thereon.
This pin stub is installed in the disperser NEBULA 1 (Phenom-World), the toner is raised at the sample inlet of the disperser, the pressure inside the disperser is reduced to 10 kPa, and the Φ25 mm sample inlet is opened for about 0.1 second. Then, the toner is introduced into the disperser. By introducing the toner sample, the pressure in the disperser rises to 20 kPa. Under such conditions, the toner collides with the air flow of about 7.3 m / sec on the substrate of the pin stub. Next, after maintaining the state for 1 minute, the inside of the disperser is brought to normal pressure, and the pin stub is taken out. When normalizing the inside of the disperser, air is introduced into the disperser at a speed of about 10 kPa / 5 seconds.
Describes the results of SEM observation of carbon particle on the pin stub surface and inorganic fine particles on mica by SEM proX PREMIUM (manufactured by PHENOM-WORLD) and particle size distribution measurement by particle metric software (manufactured by PHENOM-WORLD). To do.

In the SEM observation of the toner on the carbon tape, 10 SEM photographs were taken at random in a visual field region of 181 and 13.5 μm square. One SEM photograph taken at a 181 μm square is shown in FIG. Only toner particles were observed on the carbon tape, and no liberation of external additives could be observed.
When the total number of toners for 10 SEM photographs was measured with particle metric software, it was found that toner particles were present at a density of 586 particles / mm ² .
Similarly, 10 SEM photographs were taken on a mica with a 13.5 μm square field of view. Although SEM photographs were taken at random, a place where there was no toner in the SEM pictures was selected and photographed. An example of the SEM photograph on mica is shown in FIG.
Many inorganic fine particles were observed on the mica. When the total number of inorganic fine particles for 10 SEM photographs was measured using particle metric software, it was found that the inorganic fine particles were present at a density of 8477366 particles / mm ² .
Accordingly, it was found that in this toner, 1446 inorganic fine particles are released from one toner particle.

<Toner base particles>
The toner base particles contain a binder resin, and may further contain other components such as a colorant, a release agent, and a charge control agent as necessary.
<< Binder resin >>
The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a styrene resin (a styrene or a homopolymer or copolymer containing a styrene substitution product), a vinyl chloride resin, and styrene. / Vinyl acetate copolymer, rosin modified maleic acid resin, phenol resin, epoxy resin, polyethylene resin, polypropylene resin, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene / ethyl acrylate copolymer, xylene resin, polyvinyl butyral Examples thereof include resins, petroleum resins, and hydrogenated petroleum resins.
Examples of the styrene resin (a homopolymer or copolymer containing styrene or a styrene-substituted product) include polystyrene, chloropolystyrene, poly α-methylstyrene, styrene / chlorostyrene copolymer, styrene / propylene copolymer, and styrene. / Butadiene copolymer, styrene / vinyl chloride copolymer, styrene / vinyl acetate copolymer, styrene / maleic acid copolymer, styrene / acrylic acid ester copolymer (styrene / methyl acrylate copolymer, styrene / Ethyl acrylate copolymer, styrene / butyl acrylate copolymer, styrene / octyl acrylate copolymer, styrene / phenyl acrylate copolymer, etc.), styrene / methacrylic acid ester copolymer (styrene / methyl methacrylate) Copolymer, styrene / ethyl methacrylate copolymer , Styrene / butyl methacrylate copolymer, a styrene / phenyl methacrylate copolymer), styrene / alpha-chloromethyl acrylate copolymer, and styrene / acrylonitrile / acrylic acid ester copolymer.
There is no restriction | limiting in particular as a manufacturing method of these resin, It can select suitably, For example, block polymerization, solution polymerization, emulsion polymerization, suspension polymerization, etc. can be utilized.
These resins are not limited to single use but can be used in combination of two or more.

The binder resin used in the present invention is more preferably a polyester resin from the viewpoint of low-temperature fixability. As the polyester resin, for example, those usually obtained by condensation polymerization of an alcohol component and a carboxylic acid component can be used.
Examples of the alcohol component include glycols, 1,4-bis (hydroxymethyl) cyclohexane, ethylated bisphenols such as bisphenol A, other dihydric alcohol monomers, and trihydric or higher polyhydric alcohol monomers. Etc.
Examples of the glycols include ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol.
Examples of the carboxylic acid component include divalent organic acid monomers and trivalent or higher polyvalent carboxylic acid monomers.
Examples of the divalent organic acid monomer include maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, and malonic acid.
Examples of the trivalent or higher polyvalent carboxylic acid monomer include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, and 1,2 1,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methylenecarboxypropane, 1,2,7,8-octanetetracarboxylic acid and the like.
In particular, the polyester resin preferably has a glass transition point Tg of 55 ° C. or higher, more preferably 60 ° C. or higher, in view of heat resistant storage stability.
The DSC measurement (endothermic peak or glass transition point Tg) in the present invention is measured by using a differential scanning calorimeter (“DSC-60”; manufactured by Shimadzu Corporation) and increasing the temperature to 20 to 150 ° C. at 10 ° C./min. .

-Combined use of crystalline polyester resin-
When crystalline polyester is contained in the binder resin, low-temperature fixability and heat-resistant storage stability can be imparted to the toner due to its sharp melt property.
When the crystalline polyester is used in combination with the binder resin, it preferably has an endothermic peak due to the crystalline polyester resin in the range of 90 to 130 ° C. in the endothermic peak measurement of the toner by DSC (differential scanning calorimetry). If the endothermic peak due to the crystalline polyester resin is in the range of 90 to 130 ° C., the crystalline polyester resin does not melt at room temperature, and the toner melts in a relatively low fixing temperature region and is fixed on the recording medium. Therefore, the heat resistant storage stability and the low temperature fixability can be expressed more effectively.
Also, the endothermic amount of the endothermic peak is preferably 1 J / g or more and 15 J / g or less.
When the endothermic amount is 1 J / g or more, the amount of the crystalline polyester resin that works effectively in the toner is too small, so that the problem that the function of the crystalline polyester resin is not sufficiently exhibited can be effectively prevented. When the endothermic amount is 15 J / g or less, the amount of the crystalline polyester resin effective in the toner is excessive, so that it is possible to effectively prevent the problem that the heat resistant storage stability is lowered.

"DSC measurement"
The DSC measurement (endothermic peak, glass transition temperature Tg) in the present invention is measured by using a differential scanning calorimeter (“DSC-60”; manufactured by Shimadzu Corporation) and increasing the temperature to 20 to 150 ° C. at 10 ° C./min. .
In the present invention, the endothermic peak derived from the crystalline polyester is present in the vicinity of 80 to 130 ° C., which is the melting point of the crystalline polyester, and the endothermic amount is determined from the area surrounded by the baseline and the endothermic curve. In general, the endothermic amount in DSC measurement is often measured by increasing the temperature twice, but the endothermic peak and glass transition temperature in the present invention are measured using the endothermic curve at the first temperature increase. derive.
When the endothermic peak derived from the crystalline polyester overlaps the endothermic peak of the wax, the endothermic amount of the wax is subtracted from the endothermic amount of the overlapped peak. The endothermic amount of the wax is calculated from the endothermic amount of the wax alone and the wax content in the toner.

The crystalline polyester resin refers to a polyester resin that has a particularly high ratio of taking a crystal structure in which the main chain is regularly oriented, and the viscosity of the resin changes greatly in the vicinity of the melting point.
Examples of the crystalline polyester resin include, as an alcohol component, a saturated aliphatic diol compound having 2 to 12 carbon atoms (particularly 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1, 10-decanediol, 1,12-dodecanediol, and derivatives thereof) and a dicarboxylic acid having 2 to 12 carbon atoms having a double bond (C = C bond) as an acid component, or 2 to 2 carbon atoms 12 saturated dicarboxylic acids (especially fumaric acid, 1,4-butanedioic acid, 1,6-hexanedioic acid, 1,8-octanedioic acid, 1,10-decanedioic acid, 1,12-dodecanedioic acid, And crystalline polyester resins synthesized using these derivatives).
Among them, in particular, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and 1 in that the difference between the endothermic peak temperature and the endothermic shoulder temperature is further reduced. , 12-dodecanediol alcohol component, fumaric acid, 1,4-butanedioic acid, 1,6-hexanedioic acid, 1,8-octanedioic acid, 1,10-decanedioic acid, And 1,12-dodecanedioic acid, preferably only one kind of dicarboxylic acid component.
In addition, as a method for controlling the crystallinity and softening point of the crystalline polyester resin, trivalent or higher polyhydric alcohol such as glycerin as an alcohol component and trivalent or higher valency such as trimellitic anhydride as an acid component at the time of polyester synthesis. And a method of designing and using a non-linear polyester subjected to condensation polymerization by adding a polyvalent carboxylic acid.
The molecular structure of the crystalline polyester resin can be confirmed by X-ray diffraction, GC / MS, LC / MS, IR measurement, etc. in addition to NMR measurement by solution or solid.
The content of the crystalline polyester resin in the toner is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0% by mass to 15% by mass with respect to 100% by mass of the total binder resin. 5 mass%-15 mass% are more preferable. When the content is 5% by mass or less, the effect on low-temperature fixability is sufficiently obtained. Further, since the crystalline polyester resin has a relatively low stress resistance, if the content is 15% by mass or less, the external additive is buried in the crystalline polyester resin portion on the surface of the toner base, so that the storage stability is improved. The problem of worsening can be effectively prevented.

<<< Colorant >>>
Examples of the colorant used in the toner of the present invention include carbon black, lamp black, iron black, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6C lake, calco oil blue, chrome yellow, quinacridone, benzidine yellow, Conventionally known dyes and pigments such as rose bengal and triallylmethane dyes and pigments can be used. These can be used alone or in combination, and can be used as black toner or full color toner.
The content of these colorants is preferably 1% by mass to 30% by mass and more preferably 3% by mass to 20% by mass with respect to the binder resin component of the toner.

<<< release agent >>>
A conventionally well-known thing can be used as said mold release agent. For example, low molecular weight polyethylene, low molecular weight polypropylene and other low molecular weight polyolefin waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax, beeswax, carnauba wax, candelilla wax, rice wax, montan wax and other natural waxes, Examples include petroleum waxes such as paraffin wax and microcrystalline wax, higher fatty acids such as stearic acid, palmitic acid and myristic acid, metal salts of higher fatty acids, higher fatty acid amides, synthetic ester waxes, and various modified waxes thereof.
Among these release agents, carnauba wax and its modified wax, polyethylene wax, and synthetic ester wax are preferably used.
These release agents can be used alone or in combination of two or more.
The content of these release agents is preferably 2% by mass to 15% by mass with respect to the binder resin of the toner. If it is 2% by mass or more, there is an effect of preventing hot offset, and if it is 15% by mass or less, it is possible to prevent deterioration of transferability and durability.
The melting point of the release agent is preferably 70 ° C to 150 ° C. If it is 70 degreeC or more, the fall of the heat-resistant storage property of a toner can be prevented. If it is 150 degrees C or less, the effect of releasability can be exhibited.

<<< Charge Control Agent >>>
The charge control agent is not particularly limited. For example, nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified) (Including quaternary ammonium salts), alkylamides, phosphorus simple substances or compounds, tungsten simple substances or compounds, fluorosurfactants, salicylic acid metal salts, salicylic acid derivative metal salts, copper phthalocyanine, perylene, quinacridone, azo pigments, etc. And two or more of them may be used in combination. Examples of the charge control agent other than these include polymer compounds having a functional group such as a sulfonic acid group, a carboxyl group, and a quaternary ammonium base.
The content of these charge control agents is 0.1% by mass to 10% by mass, preferably 1% by mass to 5% by mass with respect to the binder resin component of the toner.

<Inorganic fine particles>
The inorganic fine particles are externally added to the toner base particles. In the present invention, at least two kinds of inorganic fine particles are used. Here, different types mean that the primary particles in the inorganic fine particles have different number average particle diameters or different materials, but in the present invention, at least two kinds of inorganic fine particles having different primary particle number average particle diameters are used. It is preferable to use it.
The content of the inorganic fine particles contained in the toner is a value obtained by adding the contents of a plurality of types of inorganic fine particles, and is 1.0% by mass to 3.5% by mass with respect to the toner base particles.

The inorganic fine particles added as an external additive to the toner base particles are not particularly limited and can be appropriately selected according to the purpose. For example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, titanium Calcium oxide, strontium titanate, fluorine compound, iron oxide, copper oxide, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide , Zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride and the like.
Among these, it is preferable that the inorganic fine particles contain at least one oxide or composite oxide selected from silica, titanium, alumina, and fluorine compounds because good fluidity can be obtained.

Examples of the silica fine particles include dry silica or fumed silica produced by vapor phase oxidation of silicon halide, wet silica produced from water glass, sol-gel silica produced by a sol-gel method, and the like. As the inorganic fine particles, dry silica having less silanol groups on the surface and inside the silica fine particles and less Na ₂ O and SO ₃ is preferable. The dry silica may be composite fine particles of silica and another metal oxide produced by using a metal halogen compound such as aluminum chloride or titanium chloride together with a silicon halogen compound in the production process.

The surface of the inorganic fine particles is preferably subjected to a hydrophobizing treatment from the viewpoints of adjusting the charge amount of the toner, improving the environmental stability, improving the characteristics under a high humidity environment, and the like. This is because when the inorganic fine particles added to the toner absorb moisture, the charge amount as the toner is lowered, the developing property and the transfer property are liable to be lowered, and the durability tends to be lowered.
For example, the method of hydrophobizing the inorganic fine particles includes a method of chemically treating with an organosilicon compound that reacts or physically adsorbs with the inorganic fine particles. In the present invention, inorganic fine particles that have been subjected to a hydrophobic treatment or not subjected to a hydrophobic treatment may be treated with silicon oil.
Examples of the hydrophobizing agent to be surface-treated include unmodified silicone varnish, various modified silicone varnishes, unmodified silicone oil, various modified silicone oils, silane compounds, silane coupling agents, other organosilicon compounds, or organotitanium. Compounds. These treatment agents may be used alone or in combination.

A preferred example of the treatment of silica fine particles preferably used in the toner of the present invention will be described.
In the present invention, the silica fine particles are preferably silica fine particles obtained by treating the raw silica fine particles with silicone oil and then treating with the silane or silazane compound. Transferability, charging stability in a high-temperature and high-humidity environment, and fluidity after high-temperature storage can be achieved at a higher level.
The silica fine particles are more preferably those obtained by crushing the raw silica fine particles after treating them with silicone oil. By performing the crushing treatment, the fluidity of the toner is further enhanced.

Furthermore, in the present invention, the silica fine particle is preferably 0.50% by mass or less, and 0.10% by mass or less, in the silica fine particle surface-treated with silicone oil, using hexane. More preferably. In this case, reduction of free oil in high-temperature storage can be expected, fluidity after high-temperature storage is good, and solid image followability is good.
The amount of the extracted silicone oil can be appropriately controlled according to the amount of treatment and the treatment temperature when the raw silica fine particles are treated with the silicone oil.

Furthermore, in the present invention, the hydrophobicity of the silica fine particles is preferably 95% or more and 100% or less, and more preferably 97% or more and 100% or less. When the hydrophobization rate of the silica fine particles is 95% or more, the charging stability during storage in a high temperature and high humidity environment is further improved. The hydrophobization rate of the silica fine particles can be controlled by the treatment amount and treatment conditions of the silane or silazane compound.
As the silicone oil used for the treatment of the silica fine particles of the present invention, a known silicone oil can be used without particular limitation, but straight silicone is particularly preferable.
More specifically, for example, dimethyl silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, fluorine-modified silicone oil, or methylhydrogen silicone oil can be used.
The method for treating the silicone oil may be, for example, mixing silica fine particles and silicone oil directly using a mixer such as a Henschel mixer, or may be a method of stirring the raw silica fine particles while spraying the silicone oil. Alternatively, it may be prepared by dissolving or dispersing silicone oil in an appropriate solvent (preferably adjusted to pH 4 with an organic acid or the like), mixing with the raw silica fine particles, and then removing the solvent. In addition, put the silica fine particles into the reaction vessel, add alcohol water while stirring under a nitrogen atmosphere, introduce a silicone oil treatment liquid into the reaction vessel to perform surface treatment, and then heat and stir to remove the solvent. You may take the method to do.

As the silane or silazane compound used for the treatment of the silica fine particles of the present invention, a known silane or silazane compound can be used without particular limitation.
Specifically, hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchloro. Silane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilyl mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, or diphenyl Examples include diethoxysilane. Among these, hexamethyldisilazane is preferably used from the viewpoint of processing uniformity and coupling bond reliability. Silane compounds or silazane compounds can be used alone or in combination of two or more.

The treatment with at least one of the silane or silazane compound necessary for obtaining the silica fine particles of the present invention is a dry treatment in which the vaporized silane or silazane compound is reacted with the raw silica fine particles made into a cloud by stirring, or the raw material It can be processed by a generally known method such as a wet method in which silica fine particles are dispersed in a solvent and a silane or silazane compound is dropped.
In this invention, when processing with a silane compound or a silazane compound, it is good to use 1 mass part or more and 50 mass parts or less of a silane compound or a silazane compound with respect to 100 mass parts of original silica fine particles.
In addition, it can replace with a silica fine particle and can perform a hydrophobization process by the method similar to the above-mentioned method.

Of the inorganic fine particles, at least one kind of inorganic fine particles preferably has a number average particle size of primary particles in the range of 40 nm to 200 nm. If the number average particle diameter is 40 nm or more, it is resistant to thermal or mechanical stress, and if it is 200 nm or less, it is possible to prevent a decrease in fluidity of the toner. Therefore, in order to prevent filming while maintaining good chargeability, the number average particle diameter of the inorganic fine particles as an external additive is preferably 40 nm to 200 nm. The number average particle size of the inorganic fine particles is more preferably 70 nm to 150 nm.
The number average particle diameter of the inorganic fine particles is preferably 1/5 or less of the number average particle diameter of the toner, and more preferably 1/10 or less.

In the present invention, it is preferable to add a plurality of types of the inorganic fine particles. In addition to the inorganic fine particles having a number average particle size of 40 nm to 200 nm, it is also preferable to add inorganic fine particles having a number average particle size of 2 nm to 10 nm. . Those having a large particle size act as a spacer for suppressing contact between the toner and the member, and those having a small particle size impart fluidity to the toner. The larger the particle size of the inorganic fine particles, the easier it is to be released from the toner. However, by making the inorganic fine particles chargeable with a polarity opposite to that of the toner, adhesion by electrostatic force can be imparted and release can be suppressed.
Inorganic fine particles having a number average particle diameter of 2 nm to 10 nm are preferable in that they are effective in both preventing filming and imparting toner fluidity. If the number average particle diameter is 2 nm or more, the fluidity is good, and the embedding of inorganic fine particles into the toner base particles occurs due to stress in the development process, increasing the non-electrostatic adhesion of the toner particles, and the photoconductor It is possible to effectively prevent the problem of deterioration of filming. Further, when the number average particle diameter is 10 nm or less, it is possible to effectively prevent the problem that the fluidity function is not sufficiently exhibited by reducing the contact area by adhering to the toner surface.

-Measurement of particle size of inorganic fine particles-
In the present invention, the particle size of the inorganic fine particles can be measured as follows. Inorganic fine particles are observed with a TEM (transmission electron microscope, Hitachi H-9000NAR), 100 particles are selected at random, and the particle size is calculated with image processing software (Nikore image analyzer Luzex AP). Obtain the average particle size.

<Toner characteristics>
<< Average particle diameter of toner >>
In the toner of the present invention, the number average particle diameter is preferably 3.0 μm or more.
In order to obtain a high image quality excellent in fine line reproducibility and the like, the number volume average particle diameter is more preferably 4 μm to 10 μm.
If it is 3 μm or more, the image quality can be kept good without affecting the cleaning performance in the development process and the transfer efficiency in the transfer process. If it is 10 μm or less, the fine line reproducibility of the image can be kept good.
-Toner number average particle diameter-
The number average particle diameter of the toner can be measured by various methods. For example, Coulter Multisizer III manufactured by Coulter Electronics, USA can be used.

<< Average circularity >>
In the toner of the present invention, the average circularity is preferably 0.910 to 0.975.
In particular, when the toner is a toner manufactured by a polymerization method among the toner manufacturing methods described below, a toner having an average circularity of 0.930 to 0.975 can be easily obtained. In the case of the toner manufactured by the above, toner having an average circularity of 0.910 to 0.965 is easily obtained.

-Average circularity-
The average circularity of the toner can be measured by a flow type particle image analyzer FPIA-3000 (manufactured by Toa Medical Electronics Co., Ltd.). As a specific measurement method, a surfactant, preferably alkylbenzene sulfonate, is added in an amount of 0.1 mL to 0.5 mL as a dispersant in 100 mL to 150 mL of water from which impure solids have been removed in advance, and a measurement sample is further added. About 0.1 to 0.5 g. The suspension in which the sample is dispersed is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the concentration and dispersion of the toner are adjusted by the above apparatus with the dispersion concentration being 3,000 / μL to 10,000 / μL. Obtained by measuring.

<< Average thickness of shell structure >>
When the toner cross section is observed by ruthenium dyeing with respect to the toner, the toner has a core / shell structure having a different composition due to a contrast difference. 1/60 to 1/10 is preferable because the hardness of the surface of the base toner is appropriate and the external additive is prevented from being buried or released.
Specifically, the average thickness of the shell structure can be measured as follows.
After the toner is embedded in an epoxy resin and cured, the cross section is cut out with a knife, and an ultrathin section of toner having a thickness of 80 nm is prepared using an ultramicrotome ULTRACUT UCT (manufactured by Leica). Next, the ultrathin section is gas-exposed with ruthenium tetroxide for 5 minutes to distinguish and stain the shell and the core. Further, using a TEM (transmission electron microscope) H7000 (manufactured by Hitachi High-Tech), an ultrathin section of the toner is observed at an acceleration voltage of 100 kV, and the thickness of the shell is measured. At this time, the thickness of the shell of the toner 10 particles is measured, and the average value is calculated.
When ruthenium dyeing is performed on a toner having a number average particle diameter of 6 μm, shell layers having different contrasts are observed on the surface with an average thickness of 100 nm to 600 nm.

<Toner production method>
The toner of the present invention can be obtained by externally adding the inorganic fine particles to the toner base particles.
The toner base particles can be obtained by various production methods such as a pulverization method and a polymerization method (suspension polymerization, emulsion polymerization, dispersion polymerization, emulsion aggregation, emulsion association, etc.).
The toner of the present invention is preferably a toner having a small particle size and a nearly spherical shape so as to output a high-quality and high-definition image. Therefore, the toner production method is preferably a suspension polymerization method, an emulsion polymerization method, a polymer suspension method, or the like, in which an oil phase is emulsified, suspended or aggregated in an aqueous medium to form toner base particles.

<< Suspension polymerization method >>
Disperse a colorant, a release agent, a charge control agent, etc. in an oil-soluble polymerization initiator or polymerizable monomer, and emulsify and disperse it in an aqueous medium containing a surfactant, other solid dispersant, etc. . At this time, the particle size of the release agent is controlled by conditions such as the stirring speed and temperature for dispersing the release agent. Thereafter, after a polymerization reaction to form particles, a wet process for attaching inorganic fine particles to the surface of the toner base particles in the present invention may be performed. At that time, it is preferable to treat the toner particles from which excess surfactant and the like are removed by washing.
Examples of the polymerizable monomer include acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride, acrylamide, methacrylamide, di Functional groups are introduced on the surface of toner particles by using a part of acetone acrylamide or these methylol compounds, vinyl pyridine, vinyl pyrrolidone, vinyl imidazole, ethyleneimine, acrylates and methacrylates with amino groups such as dimethylaminoethyl methacrylate. it can.
Further, by selecting a dispersant having an acid group or a basic group as a dispersant to be used, the dispersant can be adsorbed and left on the particle surface to introduce a functional group.

<< Emulsion polymerization aggregation method >>
A water-soluble polymerization initiator and a polymerizable monomer are emulsified in water using a surfactant, and a latex is synthesized by an ordinary emulsion polymerization technique. Separately, a dispersion in which a colorant, a release agent having a controlled particle size, a charge control agent, and the like are dispersed in an aqueous medium is prepared. After mixing, the toner base particles are agglomerated to a toner size and heat-fused. obtain. Thereafter, wet processing of the inorganic fine particles may be performed. A functional group can be introduced on the surface of the toner particles by using a latex similar to the monomer that can be used in the suspension polymerization method.

<< Polymer suspension method >>
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. In the oil phase of the toner composition, a binder, a prepolymer, a colorant such as a pigment, a release agent with a controlled particle size, a charge control agent, and the like are dissolved or dispersed in a volatile solvent.
An oil phase composed of a toner composition is dispersed in an aqueous medium in the presence of a surfactant, a solid dispersant and the like, and a prepolymer is reacted to form particles. Thereafter, wet processing of the inorganic fine particles may be performed.

<< Dry grinding method >>
As an example of the pulverization system, a step of mechanically dry-mixing raw materials including at least a binder resin, a colorant, a charge control agent and a release agent, a step of melt-kneading, a step of pulverizing, and a step of classifying A method for producing a toner having the above can be applied. Further, in order to improve the dispersibility of the colorant, the colorant may be mixed with other raw materials after the masterbatch treatment and processed to the next step.
The mixing step for mechanical mixing may be performed under normal conditions using a normal mixer using rotating wings, and is not particularly limited. When the above mixing process is completed, the mixture is then charged into a kneader and melt-kneaded. As the melt kneader, a uniaxial or biaxial continuous kneader or a batch kneader using a roll mill can be used. Specific apparatuses for kneading the toner include batch type two rolls, a Banbury mixer and a continuous type twin screw extruder, for example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type twin screw manufactured by Toshiba Machine Co., Ltd. Extruder, KCK twin screw extruder, Ikegai Iron Works PCM type twin screw extruder, Kurimoto Iron Works KEX type twin screw extruder, continuous single screw kneader, such as Bus Etc. are preferably used. The melt-kneaded product obtained as described above is cooled and then pulverized. For pulverization, for example, coarsely pulverized using a hammer mill, a funnel plex, etc. A machine can be used. The pulverization is desirably performed so that the number average particle diameter is 3 μm to 10 μm.
Further, the pulverized product is adjusted in particle size to 2.5 μm to 20 μm by a wind classifier or the like.
In the pulverization method, the thickness of the kneaded product is preferably 2.5 mm or more and more preferably 2.5 mm or more and 8 mm or less in the cooling step after melt-kneading the raw materials. The cooling rate of the kneaded product is slowed down, and the time for recrystallization of the crystalline polyester resin melted in the kneaded product is increased, so that recrystallization is promoted and the function of the crystalline polyester resin is more effectively performed. It can be demonstrated. In order to promote recrystallization, it is an effective means to add a fatty acid amide as described above, but the effect can also be obtained by adjusting the production process in this way. There is no upper limit to the thickness of the kneaded product, but if it is thicker than 8 mm, the efficiency is significantly reduced in the pulverization step, and the peak ratio C / R is increased.

Next, external addition of inorganic fine particles is performed on the toner base particles. By mixing and stirring the toner base particles and the inorganic fine particles using a mixer, the inorganic fine particles as the external additive are coated on the surface of the toner base particles while being crushed.
The mixing apparatus that can be used is not particularly limited as long as the powder can be mixed, and a known apparatus can be used. For example, a V-type mixer, a rocking mixer, a Ladige mixer, a Nauter mixer, a Henschel mixer, a Q For example, a mixer. These mixing devices are preferably those equipped with a jacket or the like and capable of adjusting the internal temperature.
The adhesion strength of the inorganic fine particles to the toner base surface can be controlled by changing the peripheral speed of the rotating blades of the mixing device or changing the mixing / stirring time. Further, when inorganic fine particles are externally added while applying heat to the mixing apparatus, the surface is softened and the inorganic fine particles can be embedded in the toner base surface, so that the adhesion strength to the toner base surface can be controlled.

(Developer)
The developer of the present invention contains at least the toner and, if necessary, other components such as a carrier as appropriate.
For this reason, it is excellent in transferability, chargeability, etc., and a high quality image can be formed stably. The developer may be a one-component developer or a two-component developer. However, when used in a high-speed printer or the like that supports an increase in information processing speed in recent years, the lifetime is shortened. A two-component developer is preferred because it improves.

<Career>
There is no restriction | limiting in particular as said carrier, What is necessary is just to select suitably according to the objective, For example, a magnetic carrier and a resin carrier are mentioned. As the magnetic carrier, conventionally known ones such as iron powder, ferrite powder, magnetite powder, magnetic resin carrier having a particle diameter of about 20 to 200 μm can be used. The content ratio of the carrier and the toner in the developer is preferably 1 part by mass to 10 parts by mass of the toner with respect to 100 parts by mass of the carrier.
The carrier preferably has a core material and a resin layer covering the core material.

(Toner storage unit)
The toner storage unit in the present invention refers to a unit in which toner is stored in a unit having a function of storing toner. Here, examples of the toner storage unit include a toner storage container, a developing device, and a process cartridge.
The toner container is a container that contains toner.
The developing device is a unit having a means for containing and developing toner.
The process cartridge is a cartridge in which at least an electrostatic latent image carrier (also referred to as an image carrier) and a developing unit are integrated, accommodates toner, and is detachable from the image forming apparatus. The process cartridge may further include at least one selected from a charging unit, an exposure unit, and a cleaning unit.
By attaching the toner containing unit of the present invention to an image forming apparatus to form an image, the external additive on the photoreceptor can be used not only at normal temperature and humidity but also repeatedly for a long time particularly in a low temperature and low humidity environment. Abnormal images caused by filming due to filming do not occur, and high-density and high-definition images are formed with long-term image stability by taking advantage of the characteristics of the toner that can stably ensure high image density be able to.

(Image forming apparatus and image forming method)
The image forming apparatus of the present invention includes at least an electrostatic latent image carrier, an electrostatic latent image forming unit, and a developing unit, and further includes other units as necessary.
The image forming method according to the present invention includes at least an electrostatic latent image forming step and a developing step, and further includes other steps as necessary.
The image forming method can be preferably performed by the image forming apparatus, the electrostatic latent image forming step can be preferably performed by the electrostatic latent image forming unit, and the developing step can be performed by the developing unit. The other steps can be preferably performed by the other means.
More preferably, the image forming apparatus of the present invention is an electrostatic latent image carrier, an electrostatic latent image forming unit that forms an electrostatic latent image on the electrostatic latent image carrier, and the electrostatic latent image carrier. The electrostatic latent image formed on the body is developed with toner to form a toner image, and a developing means including toner, and the toner image formed on the electrostatic latent image carrier are transferred to a recording medium Transfer means for transferring to the surface, and fixing means for fixing the toner image transferred to the surface of the recording medium.
In the image forming method of the present invention, more preferably, an electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic latent image carrier and the electrostatic latent image carrier formed on the electrostatic latent image carrier. A developing process for developing the electrostatic latent image with toner to form a toner image, a transfer process for transferring the toner image formed on the electrostatic latent image carrier onto the surface of the recording medium, and the recording A fixing step of fixing the toner image transferred onto the surface of the medium.
The toner is used in the developing unit and the developing step. Preferably, the toner image may be formed by using a developer containing the toner and further containing other components such as a carrier as necessary.

<Electrostatic latent image carrier>
The material, structure, and size of the electrostatic latent image carrier are not particularly limited and may be appropriately selected from known materials. Examples of the material include inorganic photoreceptors such as amorphous silicon and selenium. And organic photoreceptors such as polysilane and phthalopolymethine.

<Electrostatic latent image forming means>
The electrostatic latent image forming means is not particularly limited as long as it is a means for forming an electrostatic latent image on the electrostatic latent image carrier, and can be appropriately selected according to the purpose. Examples thereof include at least a charging member that charges the surface of the electrostatic latent image carrier and an exposure member that exposes the surface of the electrostatic latent image carrier imagewise.

<Developing means>
The developing unit is not particularly limited as long as it is a developing unit equipped with toner that develops the electrostatic latent image formed on the electrostatic latent image carrier to form a visible image, depending on the purpose. Can be selected as appropriate.

<Other means>
Examples of the other means include a transfer means, a fixing means, a cleaning means, a static elimination means, a recycling means, and a control means.

Next, one mode for carrying out the method of forming an image by the image forming apparatus of the present invention will be described with reference to FIG.
FIG. 4 is a schematic configuration diagram of an example of the image forming apparatus. Around a photosensitive drum 110 (hereinafter referred to as a photosensitive member) 110 as an image carrier, a charging roller 120 as a charging device, an exposure device 130, a cleaning device 160 having a cleaning blade, a static elimination lamp 170 as a static elimination device, and development. An apparatus 140 and an intermediate transfer member 150 as an intermediate transfer member are provided. The intermediate transfer member 150 is suspended by a plurality of suspension rollers 151 and is configured to run endlessly in the direction of the arrow by a driving unit such as a motor (not shown). A part of the suspension roller 151 also serves as a transfer bias roller for supplying a transfer bias to the intermediate transfer member, and a predetermined transfer bias voltage is applied from a power source (not shown). A cleaning device 190 having a cleaning blade for the intermediate transfer member 150 is also provided. Further, a transfer roller 180 is provided as a transfer means for transferring the developed image onto the transfer sheet 1100 as the final transfer material, facing the intermediate transfer body 150. The transfer roller 180 is applied with a transfer bias by a power supply device (not shown). Supplied. Around the intermediate transfer member 150, a corona charger 152 as a charge applying unit is provided.

The developing device 140 includes a developing belt 141 as a developer carrying member, a black (hereinafter referred to as “Bk”) developing unit 145K, a yellow (hereinafter referred to as “Y”) developing unit 145Y, and a magenta (hereinafter referred to as “below”). It is composed of a developing unit 145M (referred to as magenta) and a cyan (hereinafter referred to as C) developing unit 145C. The developing belt 141 is stretched between a plurality of belt rollers, and is configured to run endlessly in a direction indicated by an arrow by a driving unit such as a motor (not shown). Move at almost the same speed.
Since the configuration of each developing unit is common, the following description will be made only for the Bk developing unit 45K, and the other developing units 145Y, 145M, and 145C will be described in the parts corresponding to those in the Bk developing unit 145K in the drawing. Y, M, and C are appended to the numbers given to those in the unit, and the description is omitted. The Bk developing unit 145K is disposed so as to immerse the developing tank 142K containing a high-viscosity, high-concentration liquid developer containing toner particles and a carrier liquid component, and the lower part in the liquid developer in the developing tank 142K. And a coating roller 144K that thins the developer pumped from the pumping roller 143K and applies it to the developing belt 141. The application roller 144K has conductivity, and a predetermined bias is applied from a power source (not shown).
In addition to the apparatus configuration shown in FIG. 4, the apparatus configuration of the copying machine according to the present embodiment is an apparatus configuration in which development units 145 of the respective colors are provided around the photoconductor 110 as shown in FIG. 5. It may be.

Subsequently, the operation of the image forming apparatus according to the present embodiment will be described. In FIG. 4, the photosensitive member 110 is uniformly charged by the charging roller 120 while being driven to rotate in the direction of the arrow, and then the reflected light from the document is imaged and projected onto the photosensitive member 110 by the exposure device 130 using an optical system (not shown). An electrostatic latent image is formed. This electrostatic latent image is developed by the developing device 140 to form a toner image as a visible image. The developer layer on the developing belt 141 is peeled off from the developing belt 141 in a thin layer state by contact with the photoconductor in the developing region, and moves to a portion where a latent image is formed on the photoconductor 110. The toner image developed by the developing device 140 is transferred to the surface of the intermediate transfer member 150 at the contact portion (primary transfer region) between the photosensitive member 110 and the intermediate transfer member 150 moving at a constant speed (primary transfer). Transcription). When transferring three or four colors to be superimposed, this process is repeated for each color to form a color image on the intermediate transfer member 150.
A corona charger 152 for applying a charge to the superimposed toner image on the intermediate transfer member is provided downstream of the contact facing portion between the photosensitive member 110 and the intermediate transfer member 150 in the rotation direction of the intermediate transfer member 150, and It is installed at a position upstream of the contact facing portion between the intermediate transfer member 150 and the transfer paper 1100. The corona charger 152 gives the toner image a true charge having the same polarity as the charge polarity of the toner particles forming the toner image, and the charge is sufficient for good transfer to the transfer paper 1100. To the toner image. The toner image is charged by a corona charger 152 and then transferred to a transfer paper 1100 conveyed in the direction of an arrow from a paper supply unit (not shown) by a transfer bias from a transfer roller 180 (secondary transfer). . Thereafter, the transfer paper 1100 onto which the toner image has been transferred is separated from the photoreceptor 110 by a separation device (not shown), and after being subjected to a fixing process by a fixing device (not shown), is discharged from the device. On the other hand, the untransferred toner is collected and removed by the cleaning device 160 on the photosensitive member 110 after the transfer, and the residual charge is discharged by the discharging lamp 170 in preparation for the next charging. A color image is usually formed with four colored toners. On one color image, toner layers of 1 to 4 layers are formed. The toner layer passes through primary transfer (transfer from the photosensitive member to the intermediate transfer belt) and secondary transfer (transfer from the intermediate transfer belt to the sheet).

-Tandem type color image forming device-
The image forming apparatus according to the present invention can also be used as a tandem color image forming apparatus. An example of an embodiment of a tandem type color image forming apparatus will be described. As shown in FIG. 6, the tandem type electrophotographic apparatus includes a direct transfer system that sequentially transfers an image on each photoconductor 1 to a sheet s conveyed by a sheet conveying belt 3 by a transfer device 2. As shown in FIG. 7, the images on the respective photoreceptors 1 are once sequentially transferred to the intermediate transfer member 4 by the primary transfer device 2, and then the images on the intermediate transfer member 4 are transferred to the sheet s by the secondary transfer device 5. There are indirect transfer systems that perform batch transfer. The secondary transfer device 5 is a transfer conveyance belt, but there is also a roller shape method.
Comparing the direct transfer type with the indirect transfer type, the former arranges the paper feeding device 6 on the upstream side of the tandem type image forming apparatus T on which the photoconductors 1 are arranged, and the fixing device 7 on the downstream side. There is a drawback in that the size increases in the sheet conveying direction. On the other hand, the latter can set the secondary transfer position relatively freely. The paper feeding device 6 and the fixing device 7 can be disposed so as to overlap the tandem type image forming apparatus T, and there is an advantage that downsizing is possible.
In the former, in order not to increase the size in the sheet conveying direction, the fixing device 7 is disposed close to the tandem type image forming apparatus T. For this reason, the fixing device 7 cannot be disposed with a sufficient margin that allows the sheet s to bend, and an impact when the leading edge of the sheet s enters the fixing device 7 (particularly with a thick sheet) or fixing. There is a drawback that the fixing device 7 tends to affect image formation on the upstream side due to the difference in speed between the sheet conveyance speed when passing through the apparatus 7 and the sheet conveyance speed by the transfer conveyance belt.

On the other hand, in the latter case, the fixing device 7 can be disposed with a sufficient margin that the sheet s can be bent, so that the fixing device 7 can hardly affect the image formation.
In view of the above, recently, an indirect transfer type among tandem type electrophotographic apparatuses has attracted attention.
In this type of color electrophotographic apparatus, as shown in FIG. 7, the transfer residual toner remaining on the photoconductor 1 after the primary transfer is removed by the photoconductor cleaning device 8 to clean the surface of the photoconductor 1. In preparation for another image formation. Further, the transfer residual toner remaining on the intermediate transfer body 4 after the secondary transfer is removed by the intermediate transfer body cleaning device 9 to clean the surface of the intermediate transfer body 4 to prepare for image formation again.

FIG. 8 shows an embodiment of the present invention, which is a tandem indirect transfer type electrophotographic apparatus. In the figure, reference numeral 100 is a copying apparatus main body, reference numeral 200 is a paper feed table on which the copying apparatus is placed, reference numeral 300 is a scanner mounted on the copying apparatus main body 100, and reference numeral 400 is an automatic document feeder (ADF) mounted thereon. ). The copying machine main body 100 is provided with an endless belt-shaped intermediate transfer member 10 at the center.
Then, as shown in FIG. 8, in the illustrated example, it is wound around three support rollers 14, 15, and 16 so that it can be rotated and conveyed clockwise in the figure.
In this illustrated example, an intermediate transfer body cleaning device 17 for removing residual toner remaining on the intermediate transfer body 10 after image transfer is provided on the left of the second support roller 15 among the three.
Further, among the three images, four images of yellow, cyan, magenta, and black are arranged on the intermediate transfer member 10 stretched between the first support roller 14 and the second support roller 15 along the conveyance direction. The tandem image forming apparatus 20 is configured by arranging the forming units 18 side by side.
An exposure device 21 is further provided on the tandem image forming apparatus 20 as shown in FIG. On the other hand, a secondary transfer device 22 is provided on the side opposite to the tandem image forming apparatus 20 with the intermediate transfer body 10 interposed therebetween. In the illustrated example, the secondary transfer device 22 is configured by spanning a secondary transfer belt 24, which is an endless belt, between two rollers 23, and is pressed against the third support roller 16 via the intermediate transfer body 10. The image on the intermediate transfer body 10 is transferred to a sheet.
A fixing device 25 for fixing the transfer image on the sheet is provided beside the secondary transfer device 22. The fixing device 25 is configured by pressing a pressure roller 27 against a fixing belt 26 that is an endless belt.
The secondary transfer device 22 described above is also provided with a sheet transport function for transporting the image-transferred sheet to the fixing device 25. Of course, a transfer roller or a non-contact charger may be arranged as the secondary transfer device 22, and in such a case, it is difficult to provide this sheet conveying function together.
In the illustrated example, a sheet reversing device 28 for reversing the sheet so as to record an image on both sides of the sheet is provided below the secondary transfer device 22 and the fixing device 25 in parallel with the tandem image forming device 20 described above. Is provided.

Now, when making a copy using this color electrophotographic apparatus, a document is set on the document table 30 of the automatic document feeder 400. Alternatively, the automatic document feeder 400 is opened, a document is set on the contact glass 32 of the scanner 300, and the automatic document feeder 400 is closed and pressed by it.
When a start switch (not shown) is pressed, when a document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32, and then the document is set on the other contact glass 32. Immediately drives the scanner 300 and travels through the first traveling body 33 and the second traveling body 34. Then, the first traveling body 33 emits light from the light source and further reflects the reflected light from the document surface toward the second traveling body 34, and is reflected by the mirror of the second traveling body 34 and passes through the imaging lens 35. The document is placed in the reading sensor 36 and the original content is read.
When a start switch (not shown) is pressed, one of the support rollers 14, 15, and 16 is driven to rotate by a drive motor (not shown), and the other two support rollers are driven to rotate to convey the intermediate transfer member 10. To do. At the same time, the individual image forming means 18 rotates the photosensitive member 40 to form black, yellow, magenta, and cyan monochrome images on the respective photosensitive members 40. Then, along with the conveyance of the intermediate transfer member 10, the single color images are sequentially transferred to form a composite color image on the intermediate transfer member 10.

On the other hand, when a start switch (not shown) is pressed, one of the paper feed rollers 42 of the paper feed table 200 is selectively rotated, and the sheet is fed out from one of the paper feed cassettes 44 provided in multiple stages in the paper bank 43, and the separation roller 45. Are separated one by one into the paper feed path 46, transported by the transport roller 47, guided to the paper feed path 48 in the copying apparatus main body 100, and abutted against the registration roller 49 and stopped.
Alternatively, the sheet feed roller 50 is rotated to feed out the sheets on the manual feed tray 51, separated one by one by the separation roller 52, put into the manual feed path 53, and abutted against the registration roller 49 and stopped.
Then, the registration roller 49 is rotated in synchronization with the composite color image on the intermediate transfer member 10, the sheet is fed between the intermediate transfer member 10 and the secondary transfer device 22, and transferred by the secondary transfer device 22. A color image is recorded on the sheet.
The image-transferred sheet is conveyed by the secondary transfer device 22 and sent to the fixing device 25. The fixing device 25 applies heat and pressure to fix the transferred image, and then the switching roller 55 is used to switch the discharge roller. The paper is discharged at 56 and stacked on the paper discharge tray 57. Alternatively, it is switched by the switching claw 55 and put into the sheet reversing device 28, where it is reversed and guided again to the transfer position, and an image is recorded also on the back surface, and then discharged onto the discharge tray 57 by the discharge roller 56.
On the other hand, the intermediate transfer body 10 after the image transfer is removed by the intermediate transfer body cleaning device 17 to remove residual toner remaining on the intermediate transfer body 10 after the image transfer, so that the tandem image forming apparatus 20 can prepare for another image formation.
Here, the registration roller 49 is generally used while being grounded, but it is also possible to apply a bias for removing paper dust from the sheet.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples. “Part” represents “part by mass” unless otherwise specified. “%” Represents “% by mass” unless otherwise specified.

(Manufacture of toner base particles 1)
<Synthesis of Crystalline Polyester Resin 1>
1,200 parts of 1,6-hexanediol, 1,200 parts of terephthalic acid, and 0.4 part of dibutyltin oxide as a catalyst in a reaction vessel equipped with a cooling pipe, a stirrer, and a nitrogen introduction pipe. After putting in, the air in a container was made into inert atmosphere with nitrogen gas by pressure reduction operation, and it stirred at 180 rpm by mechanical stirring for 7 hours. Thereafter, the temperature was gradually raised to 210 ° C. under reduced pressure, and the mixture was stirred for 1.5 hours. When it became viscous, it was air-cooled to stop the reaction to obtain [Crystalline Polyester Resin 1].
The obtained [Crystalline Polyester Resin 1] had a number average molecular weight of 4,800, a weight average molecular weight of 15,000, and a melting point of 110 ° C.

<Synthesis of Amorphous Polyester Resin 1>
In a reaction vessel equipped with a condenser, a stirrer, and a nitrogen inlet tube, 660 parts of bisphenol A ethylene oxide 2 mol adduct, 103 parts of bisphenol A propylene oxide 2 mol adduct, 283 parts of terephthalic acid, 22 parts of isophthalic acid, and 2 parts of dibutyltin oxide was added, reacted at 230 ° C. under normal pressure for 5 hours, and further reacted at reduced pressure of 10 mmHg to 15 mmHg for 5 hours. Next, 35 parts of trimellitic anhydride was added and reacted at 180 ° C. for 2 hours under normal pressure to obtain amorphous polyester resin 1.
The obtained amorphous polyester resin 1 has a number average molecular weight of 3,500, a weight average molecular weight of 18,000, a glass transition point (Tg) of 58 ° C., an acid value of 25 mgKOH / g, and a hydroxyl value of 52 mgKOH / g. there were.

-Formulation of toner base particles 1-
Crystalline polyester resin 1 10 parts by weight Amorphous polyester resin 1 90 parts by weight Colorant (carbon black): 10 parts by weight Release agent: carnauba wax (melting point: 81 ° C.) 4 parts by weight Charge control agent: monoazo Fe metal Complex 2 parts by mass

  After premixing using a Henschel mixer (Mitsui Miike Kako Co., Ltd., FM20B) according to the above prescription, kneading section 120 ° C., feeding section 100 using a biaxial kneader (Ikegai Co., Ltd., PCM-30). It was melted and kneaded at 0 ° C. The obtained kneaded material was rolled to a thickness of 2.7 mm with a roller, cooled to room temperature with a belt cooler, and coarsely pulverized to 200 μm to 300 μm with a hammer mill. Subsequently, after finely pulverizing using a supersonic jet pulverizer lab jet (manufactured by Nippon Pneumatic Industry Co., Ltd.), the number average particle size is 7. with an air flow classifier (manufactured by Nippon Pneumatic Industry Co., Ltd., MDS-I). The toner base particles 1 were obtained by classification while appropriately adjusting the louver opening so as to be 0 ± 0.2 μm. At this time, the average circularity of the toner base particles was 0.930. Further, the core / shell layer was not confirmed by cross-sectional observation.

(Manufacture of inorganic fine particles)
<Manufacture of silica fine particles 1>
-With crushing treatment-
A silica fine particle substrate (A1) (manufactured by Nippon Aerosil Co., Ltd.) having a number average particle diameter of 7 nm is charged into an autoclave equipped with a stirrer, and then heated to a temperature of 200 ° C. in a fluidized state by stirring. Got.
While stirring the inside of the reaction tank, 10 parts by weight of dimethyl silicone oil (viscosity = 50 cs) is sprayed on 100 parts by weight of the substrate 1, and after stirring for 30 minutes, the temperature is raised to 300 ° C. while stirring. The mixture was further stirred for 2 hours. Then, it took out and crushed using the pin type crushing apparatus. Next, the inside of the reactor was replaced with nitrogen gas, the reactor was sealed, and 100 parts by mass of the substrate 1 was sprayed with 10 parts by mass of hexamethyldisilazane to perform silane compound treatment.
This reaction was continued for 60 minutes, and then the reaction was terminated. After completion of the reaction, the autoclave was depressurized and washed with a nitrogen gas stream to remove excess hexamethyldisilazane and by-products. Thereafter, 1-pass crushing treatment was performed with a pulverizer (manufactured by Hosokawa Micron Corporation) to obtain silica fine particles 1 with crushing treatment.
In addition, the crushing process by the said pin-type crushing apparatus throws the base material 1 which processed the dimethyl silicone oil into the 20L Q mixer, and pulverized for 1 minute at the peripheral speed of 50 m / s.
-No crushing treatment-
Except for the crushing treatment by the pin type crushing apparatus, silica fine particles 1 without crushing treatment were obtained by the same method.

<Manufacture of silica fine particles 2>
-With crushing treatment-
A silica fine particle substrate (A4) (manufactured by Nippon Aerosil Co., Ltd.) having a primary particle number average particle size of 45 nm is charged into an autoclave equipped with a stirrer, and then heated to a temperature of 200 ° C. in a fluidized state by stirring. Got.
In the method for producing silica fine particles 1 with crushing treatment, silica fine particles 2 with crushing treatment are obtained in the same manner as the method for producing silica fine particles 1 except that the substrate 2 is used instead of the substrate 1. It was.
-No crushing treatment-
Except for the crushing treatment by the pin type crushing apparatus, silica fine particles 2 without crushing treatment were obtained by the same method as the production method of the silica fine particles 2.

<Titanium oxide fine particles 1>
As a first treatment step, 10 parts by mass of isobutyltrimethoxysilane is sprayed on 100 parts by mass of acicular rutile-type titanium oxide fine particles (manufactured by Teika) having a number average particle diameter of 15.0 nm of primary particles, and titanium oxide is then sprayed. The treatment with the silane compound was performed with the fine particles flowing. This reaction was continued for 60 minutes, and then the reaction was terminated. As a 2nd process process, 10 mass parts dimethyl silicone oil was sprayed with respect to the titanium oxide microparticles | fine-particles produced | generated by the 1st process process, and stirring was continued for 30 minutes. Thereafter, the temperature was raised to 190 ° C. with stirring, and the mixture was further stirred for 3 hours, whereby dimethylsilicone oil was baked on the surface of the titanium oxide fine particles to complete the reaction. Thereafter, the pulverizer (manufactured by Hosokawa Micron Corporation) was repeatedly pulverized until the aggregates of the titanium oxide fine particles disappeared to obtain titanium oxide fine particles 1 having a primary particle number average particle size of 15 nm.

<Manufacture of silica fine particles 3>
To a glass reactor having a stirrer, a dropping funnel and a thermometer, 693.0 g of methanol, 46.0 g of water, and 55.3 g of 28% by mass of ammonia water as alcohol solvents were added, methanol, water, A mixed solution of ammonia and ammonia was prepared. The obtained mixed solution was adjusted to a reaction temperature of 35 ° C. and stirred while maintaining the reaction temperature, and 1293.0 g (8.5 mol) of tetramethoxysilane and 464.5 g of 5.4 mass% ammonia water. At the same time, dripping was started. At this time, the dropping time of tetramethoxysilane was dropped for 8 hours. The dropping speed of ammonia water was adjusted so that dropping was completed one hour earlier than tetramethoxysilane. After completion of the dropwise addition of tetramethoxysilane, the mixture was stirred for 1 hour for hydrolysis to obtain a methanol-water dispersion of sol-gel silica fine particles. Next, the dispersion was heated to 75 ° C. to distill off 1,320 g of methanol, and then 1,320 g of water was added. The dispersion was heated to 90 ° C. to distill off 532.4 g of methanol to obtain an aqueous dispersion of sol-gel silica fine particles. After 1,584 g of methyl isobutyl ketone was added to this aqueous dispersion, the mixture was heated to 90 ° C. to 110 ° C., and 1,474 g of a mixture of methanol and water was distilled off over 15 hours. After cooling the obtained methyl isobutyl ketone dispersion of sol-gel silica fine particles to 25 ° C., 322 g of hexamethyldisilazane (2.0 mol, 0.24 mol relative to 1 mol of SiO ₂ unit) was added as a surface treatment agent. The sol-gel silica fine particles were subjected to a surface treatment by heating to 130 ° C. and reacting for 7 hours. By removing the solvent from this dispersion under reduced pressure at 80 ° C., silica fine particles 3 having a primary particle number average particle size of 110 nm were obtained.

(Manufacture of toner base particles 2)
<Resin particle dispersion 1>
In a reaction vessel equipped with a stirrer and a thermometer, 683 parts of ion-exchanged water, 11 parts of sodium salt Eleminol RS-30 (manufactured by Sanyo Kasei Kogyo Co., Ltd.) of sulfuric acid ester of methacrylic acid ethylene oxide, 10 parts of polylactic acid, 60 parts of styrene, 100 parts of methacrylic acid, 70 parts of butyl acrylate, and 1 part of ammonium persulfate were charged and stirred at 3.8 × 10 ³ rpm for 40 minutes. Next, after heating up to 75 degreeC and making it react for 5 hours, 30 mass parts of 1 mass% ammonium persulfate aqueous solution was added, and it age | cure | ripened at 75 degreeC for 7 hours, and the resin particle dispersion liquid 1 was obtained.
It was 320 nm when the volume average particle diameter of the resin particle dispersion 1 was measured using a laser diffraction / scattering particle size distribution analyzer LA-920 (manufactured by Horiba Ltd.). Moreover, when the resin of the resin particle dispersion 1 was isolated, the glass transition point was 59 ° C. and the weight average molecular weight was 6 × 10 ⁴ .

<Intermediate polyester 1>
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 229 parts of an ethylene oxide 2-mole adduct of bisphenol A, 264 parts of a propylene oxide 3-mole adduct of bisphenol A, 208 parts of terephthalic acid, 80 parts of adipic acid And 2 parts of dibutyltin oxide were added and reacted at 230 ° C. for 9 hours under normal pressure, and then allowed to react for 5 hours under reduced pressure of 10 mmHg to 15 mmHg. Next, 35 parts of trimellitic anhydride was added and reacted at 180 ° C. for 2 hours under normal pressure to obtain Intermediate Polyester 1. The intermediate polyester 1 had a number average molecular weight of 1.8 × 10 ³ , a weight average molecular weight of 3.5 × 10 ³ , a glass transition point of 38 ° C., and an acid value of 25 KOH mg / g.
<Prepolymer 1>
Next, 410 parts of intermediate polyester 1, 89 parts of isophorone diisocyanate and 500 parts of ethyl acetate are placed in a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, and reacted at 100 ° C. for 5 hours to produce a prepolymer. 1 was obtained. Prepolymer 1 had a free isocyanate content of 1.53% by mass.
<Ketimine 1>
In a reaction vessel equipped with a stirrer and a thermometer, 170 parts of isophoronediamine and 75 parts of methyl ethyl ketone were charged and reacted at 50 ° C. for 4 and a half hours to obtain ketimine 1. Ketimine 1 had an amine value of 417 KOH mg / g.
<Aqueous medium 1>
990 parts of ion-exchanged water, 83 parts of resin particle dispersion 1, 37 parts of a 48.3% by weight aqueous solution of sodium dodecyl diphenyl ether disulfonate, Eleminol MON-7 (manufactured by Sanyo Chemical Industries) and 90 parts of ethyl acetate are mixed and stirred. A milky white aqueous medium 1 was obtained.

<Master batch 1>
1,200 parts of ion-exchanged water, 540 parts of carbon black Printex 35 (manufactured by Dexa) having a DBP oil absorption of 42 mL / 100 mg and a pH of 9.5, and 1,200 parts of polyester 1 were added to a Henschel mixer (Mitsui Mining Co., Ltd.). And then kneaded for 1 hour at 110 ° C. using two rolls, cooled by rolling, and pulverized with a pulverizer to obtain a master batch 1.
<Dispersion 1>
In a container equipped with a stir bar and a thermometer, 378 parts of polyester 1, 100 parts of paraffin wax with a glass transition point of 71 ° C. and 947 parts of ethyl acetate are charged, heated to 80 ° C. and kept for 5 hours while stirring. Then, it was cooled to 30 ° C. in 1 hour. Next, 500 parts of Masterbatch 1 and 500 parts of ethyl acetate were added and mixed for 1 hour. 1,324 parts of the obtained mixed liquid was transferred to a container, and using a bead mill Ultra Visco Mill (manufactured by IMEX), the liquid feeding speed was 1 kg / hour, the peripheral speed of the disk was 6 m / second, and the particle size was 0. Filled with 80% by volume of 5 mm zirconia beads and dispersed under conditions of 3 passes. Next, 1,324 parts of a 65% by mass ethyl acetate solution of polyester 1 was added, and two passes were performed using a bead mill under the above conditions to obtain dispersion 1. When dispersion 1 was dried at 130 ° C. for 30 minutes, the solid content concentration was 50% by mass.
<Emulsified slurry 1>
749 parts of dispersion 1, 115 parts of prepolymer 1 and 2.9 parts of ketimine 1 were placed in a container and mixed for 2 minutes at 5 × 10 ³ rpm using a TK homomixer (manufactured by Tokushu Kika). Then, 1,200 parts of aqueous medium 1 was added and mixed for 25 minutes at 1.3 × 10 ⁴ rpm using a TK homomixer to obtain emulsified slurry 1.
<Dispersion slurry 1>
The emulsified slurry 1 was put into a container in which a stirrer and a thermometer were set, and after removing the solvent at 30 ° C. for 8 hours, it was aged at 40 ° C. for 24 hours to obtain a dispersed slurry 1.
<Filter cake>
After 100 parts of the dispersion slurry 1 were filtered under reduced pressure, 100 parts of ion-exchanged water was added to the filter cake, and the mixture was mixed for 10 minutes at 1.2 × 10 ⁴ rpm using a TK homomixer, followed by filtration. To the obtained filter cake, 100 parts of a 10% by mass aqueous sodium hydroxide solution was added, and the mixture was mixed at 1.2 × 10 ⁴ rpm for 30 minutes using a TK homomixer, and then filtered under reduced pressure. 100 parts of 10% by mass hydrochloric acid was added to the obtained filter cake, and the mixture was mixed for 10 minutes at 1.2 × 10 ⁴ rpm using a TK homomixer, followed by filtration. To the obtained filter cake, 300 parts of ion-exchanged water was added, and after mixing for 10 minutes at 1.2 × 10 ⁴ rpm using a TK homomixer, an operation of filtering was performed twice to obtain a filter cake.
<Toner base particle 2>
The obtained filter cake was dried at 45 ° C. for 48 hours using a circulating dryer, and then sieved with a mesh having a mesh opening of 75 μm to obtain toner base particles 2. At this time, the toner base particles 2 had an average circularity of 0.960 and a number average particle diameter of 6.0 μm. Moreover, the average thickness of the shell structure by cross-sectional observation was 700 nm.

-Measurement of number average molecular weight and mass average molecular weight-
The number average molecular weight and the mass average molecular weight were measured as follows. Hereinafter, the number average molecular weight and the mass average molecular weight in all synthesis examples were also measured under the same conditions.
Apparatus: HLC-8220GPC (manufactured by Tosoh Corporation)
Column: TSKgel
SuperHZM-Mx3
Temperature: 40 ° C
Solvent: THF (tetrahydrofuran)
Flow rate: 0.35 mL / min Sample: 0.01 mL injection of a 0.05-0.6% concentration sample Use a molecular weight calibration curve created with a monodisperse polystyrene standard sample from the molecular weight distribution of the toner resin measured under the above conditions And calculated. As a monodisperse polystyrene standard sample, 10 samples in the range of 5.8 × 100 to 7.5 × 1,000,000 were used.
-Measurement of acid value-
The acid value was measured as follows. Hereinafter, the acid values in all synthesis examples were also measured under the same conditions.
In a conical flask, 1 g to 1.5 g of a sample was precisely weighed, and 20 mL of xylene was added thereto, followed by dissolution by heating. After dissolution, 20 mL of dioxane was added, and the solution was titrated as soon as possible with a 1% phenolphthalein solution as an indicator with a N / 10 potassium hydroxide standard methanol solution while the solution did not become cloudy or hazy. At the same time, a blank test was performed.
Acid value = [5.61 × (AB) × f] / S
However,
A: mL number of N / 10 potassium hydroxide standard methanol solution required for this test B: mL number of N / 10 potassium hydroxide standard methanol solution required for blank test f: N / 10 potassium hydroxide standard methanol solution Factor S: Sample (g)
-Measurement of hydroxyl value-
The hydroxyl value was measured as follows. Hereinafter, the hydroxyl values in all synthesis examples were also measured under the same conditions.
Measurement was performed under the following conditions in accordance with the measurement method described in JIS K0070-1966.
0.5 g of intermediate polyester 1 was precisely weighed into a 100 mL volumetric flask, and 5 mL of an acetylating reagent was correctly added thereto. Then, it was heated by being immersed in a bath at 100 ° C. ± 5 ° C. After 1 to 2 hours, the flask was taken out of the bath, allowed to cool, then added with water and shaken to decompose acetic anhydride. Further, in order to complete the decomposition, the flask was again heated in a bath for 10 minutes or more and allowed to cool, and then the wall of the flask was thoroughly washed with an organic solvent. This solution was subjected to potentiometric titration with a N / 2 potassium hydroxide ethyl alcohol solution using a potentiometric automatic hand titrator (DL-53 Titrator, manufactured by METTLER TOLEDO) to determine the hydroxyl value.
-Measurement of glass transition point-
Using a differential scanning calorimeter (DSC-60, manufactured by Shimadzu Corporation), the temperature was determined from a DSC chart when the temperature was raised from 20 ° C. to 150 ° C. at 10 ° C./min.

(Manufacture of toner base particles 3)
<Resin particle dispersion 2>
In a reaction vessel equipped with a stirrer and a thermometer, 683 parts of ion-exchanged water, 11 parts of sodium salt Eleminol RS-30 (manufactured by Sanyo Kasei Kogyo Co., Ltd.) of sulfuric acid ester of methacrylic acid ethylene oxide, 20 parts of polylactic acid, 60 parts of styrene, 100 parts of methacrylic acid, 70 parts of butyl acrylate, and 1 part of ammonium persulfate were charged and stirred at 3.8 × 10 ³ rpm for 40 minutes. Next, after heating up to 75 degreeC and making it react for 3 hours, 30 mass parts of 1 mass% ammonium persulfate aqueous solution was added, and it age | cure | ripened at 75 degreeC for 5 hours, and obtained the resin particle dispersion liquid 2.
It was 250 nm when the volume average particle diameter of the resin particle dispersion 2 was measured using a laser diffraction / scattering particle size distribution analyzer LA-920 (manufactured by Horiba, Ltd.).
Moreover, when the resin of the resin particle dispersion liquid 2 was isolated, the glass transition point was 61 ° C. and the weight average molecular weight was 5.5 × 10 ⁴ .
Toner base particles 3 were obtained in the same manner as toner base particles 2 except that resin particle dispersion 2 was used instead of resin particle dispersion 1.
Toner base particles 3 had an average circularity of 0.960 and a number average particle diameter of 6.0 μm. Moreover, the average thickness of the shell structure by cross-sectional observation was 400 nm.

Example 1
Crushed silica fine particles 1 and titanium oxide fine particles 1 were charged into a 20 L Henschel mixer at a ratio shown in Table 1 below with respect to toner base particles 1 (2 kg). The temperature of the jacket cooling water was set to 30 ° C., and the mixture was mixed and stirred under the conditions shown in Table 2 below to obtain toner particles 1 in which the surface of the toner base particles was coated with silica fine particles 1 and titanium oxide fine particles 1.
For the toner particles 1 obtained above, the number of liberated inorganic fine particles on the carbon tape and mica was measured by the following vacuum dispersion type image analysis method.
A carbon double-sided tape E3605 for SEM (manufactured by EM Japan) was attached to the surface of a φ25 × 8 aluminum pin stub (EM Japan), and mica punched to φ10 was attached thereon.
This pin stub is installed in the disperser NEBULA 1 (Phenom-World), the toner is raised at the sample inlet of the disperser, the pressure in the disperser is reduced to 10 kPa, and the sample inlet is opened for about 0.1 second. Toner was introduced into the disperser. With the introduction of the toner sample, the pressure in the disperser increased to 20 kPa. After maintaining this state for 1 minute, the inside of the disperser was brought to normal pressure, and the pin stub was taken out. When normalizing the inside of the disperser, air was introduced into the disperser at a speed of about 10 kPa / 5 seconds.
The particle size of inorganic fine particles on the carbon tape and mica on the surface of the pin stub was observed by SEM with a desktop SEM proX PREMIUM (manufactured by PHENOM-WORLD), and the particle size distribution was measured with particle metric software (manufactured by PHENOM-WORLD).
Table 3 shows the measurement results.
In addition, the following evaluation criteria are used to ensure that a high image density can be stably secured without causing abnormal images due to filming of the photoreceptor even when the toner is repeatedly used over a long period of time under normal temperature and normal humidity and low temperature and low humidity conditions. Evaluated. The results are shown in Table 4.

<Evaluation method>
In this invention, it evaluated using the following evaluation machines.
Evaluation was carried out using an evaluation machine that tuned a part of a full color copier imagio MP C4503 manufactured by Ricoh Co., Ltd., which has a four-color non-magnetic two-component developing unit and a four-color photoreceptor. The printing speed was evaluated by high-speed printing (45 sheets / min / A4).
<< Evaluation Items >>
1) Filming property in a low-temperature and low-humidity environment In a temperature-humidity environment where the temperature is 10 ° C. and the relative humidity is 15%, the adhesion adhered to the photoconductor after outputting 10,000 and 50,000 20% image area density charts. The amount of components was evaluated visually.
The case where no adhesion was observed was evaluated as ◎, the case where a slightly cloudy trace was observed was evaluated as ◯, the case where a cloudy streak could be confirmed was evaluated as △, and the case where a cloudy area was large was evaluated as ×.
Note that those evaluated as “◎”, “◯”, and “Δ” are at a level where there is no practical problem with respect to filming property, and image density unevenness is also in an allowable range.
2) Long-term image density stability 2-1) Normal temperature and normal humidity environment After outputting 30,000 and 100,000 5% image area density charts in a temperature and humidity environment at a temperature of 23 ° C. and a relative humidity of 50%, the inside Four black solids (A3 area) were continuously fed using the pattern, and the image density of the latter half of the fourth sheet was measured using X-Rite 938 (manufactured by X-Rite).
2-2) Low-temperature and low-humidity environment In a temperature-humidity environment with a temperature of 10 ° C. and a relative humidity of 15%, after outputting 5,000 and 10,000 5% image area density charts, black solid (A3 Area) was continuously passed, and the image density of the latter half of the fourth sheet was measured using X-Rite 938 (manufactured by X-Rite).
The image density of the solid black image is not practically problematic as long as ID = 1.3 or more, but it is preferable to stably maintain a high image density at the time of diameter.
3) Image under normal temperature and normal humidity environment In a temperature and humidity environment with a temperature of 23 ° C. and a relative humidity of 50%, after outputting 30,000 and 100,000 5% image area density charts, black using the internal pattern Four sheets of solid (A3 area) were continuously passed. Abnormal images such as white spots and white spots were visually confirmed on the four black solid images.

(Examples 2 to 9)
In Example 1, toners 2 to 9 were obtained in the same manner as in Example 1 except that the toner base particles, the types of inorganic fine particles, and the content of the inorganic fine particles were changed to the ratios shown in Table 1 below. It was.
The same measurements and evaluations as in Example 1 were performed on toners 2 to 9. The results are shown in Tables 3 and 4.

(Example 10)
After the toner 4 was obtained, the toner was subjected to surface modification by heat under the following conditions with a surface modification device (surfing system, manufactured by Nippon Pneumatic Kogyo Co., Ltd.) to obtain a toner 10.
Developer supply section; table feeder + vibration feeder, dispersion nozzle; 4 (symmetrical arrangement of 90 degrees each)
Ejection angle: 30 degrees Hot air flow rate = 6 m ³ / min
Injection air flow rate = 0.8 m ³ / min
Blower air volume = 10m ³ / min
Hot air temperature = 145 ° C
Feed amount (sample supply amount): 2 kg / h
Cold air temperature = 15 ° C., cooling water temperature = 5 ° C.
The same measurement and evaluation as in Example 1 were performed on the toner 10. The results are shown in Tables 3 and 4.

(Comparative Examples 1 to 4)
In Example 1, toners 12 to 15 were obtained in the same manner as in Example 1 except that the toner base particles, the types of inorganic fine particles, and the content of the inorganic fine particles were changed to the ratios shown in Table 1 below. It was.
The same measurements and evaluations as in Example 1 were performed on toners 12 to 15. The results are shown in Tables 3 and 4.

(Comparative Example 5)
After obtaining toner 10, this toner was subjected to surface modification by heat in the same manner as in Example 10 to obtain toner 16.
The same measurement and evaluation as in Example 1 were performed on the toner 16. The results are shown in Tables 3 and 4.

Aspects of the present invention are as follows, for example.
<1> A toner containing toner base particles having a binder resin and at least two kinds of inorganic fine particles,
Containing 1.0 to 3.5% by weight of the inorganic fine particles with respect to the toner base particles,
When the toner is collided using a vacuum disperser by a vacuum dispersion type image analysis method in which the toner collides with the substrate,
The number of liberated inorganic fine particles dispersed on the substrate made of carbon tape is 10 or less per one toner particle;
The number of liberated inorganic fine particles dispersed on the substrate made of mica is 200 to 1,800 per one toner particle,
The toner is characterized in that the number of liberated inorganic fine particles of 350 nm or more and 500 nm or less dispersed on the mica substrate is 50 or less per one toner particle.

<2> The toner according to <1>, wherein the inorganic fine particles contain at least one oxide or composite oxide selected from silica, titanium, alumina, and a fluorine compound.
<3> The toner according to any one of <1> to <2>, wherein at least one of the inorganic fine particles is an inorganic fine particle having a number average particle diameter of 40 nm to 200 nm.
<4> Among the inorganic fine particles, at least one kind is inorganic fine particles having a number average particle diameter of 70 nm to 150 nm, and the other one is inorganic fine particles having a number average particle diameter of 2 nm to 10 nm. The toner according to any one of <1> to <3>.
<5> When cross-sectional observation is performed on the toner,
The toner has a shell structure having a different composition due to a contrast difference,
The toner according to any one of <1> to <4>, wherein an average thickness of the shell structure is 1/60 to 1/10 of the diameter of the toner.
<6> A two-component developer comprising a carrier and the toner according to any one of <1> to <5>.
<7> A toner storage unit that stores the toner according to any one of <1> to <5>.
<8> An electrostatic latent image carrier, and electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier,
Developing means comprising toner for developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image;
Transfer means for transferring the toner image formed on the electrostatic latent image carrier onto the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium,
An image forming apparatus, wherein the toner is the toner according to any one of <1> to <5>.
<9> an electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic latent image carrier;
A developing step of developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image;
A transfer step of transferring a toner image formed on the electrostatic latent image carrier onto the surface of a recording medium;
Fixing the toner image transferred to the surface of the recording medium,
The toner is the toner according to any one of <1> to <5>.

  <1> to <5>, the toner according to <6>, the two-component developer according to <6>, the toner storage unit according to <7>, the image forming apparatus according to <8>, According to the image forming method described in <9>, the conventional problems can be solved and the object of the invention can be achieved.

Japanese Patent No. 3129074 JP 2014-174341 A

Claims (9)

A toner containing toner base particles having a binder resin and at least two kinds of inorganic fine particles,
Containing 1.0 to 3.5% by weight of the inorganic fine particles with respect to the toner base particles,
When the toner is collided using a vacuum disperser by a vacuum dispersion type image analysis method in which the toner collides with the substrate,
The number of liberated inorganic fine particles dispersed on the substrate made of carbon tape is 10 or less per one toner particle;
The number of liberated inorganic fine particles dispersed on the substrate made of mica is 200 to 1,800 per one toner particle,
The toner according to claim 1, wherein the number of liberated inorganic fine particles of 350 nm or more and 500 nm or less dispersed in the mica substrate is 50 or less per toner particle.   The toner according to claim 1, wherein the inorganic fine particles contain at least one oxide or composite oxide selected from silica, titanium, alumina, and fluorine compounds.   The toner according to claim 1, wherein at least one of the inorganic fine particles is an inorganic fine particle having a number average particle diameter of 40 nm to 200 nm.   At least one of the inorganic fine particles is an inorganic fine particle having a number average particle diameter of 70 nm to 150 nm, and the other is an inorganic fine particle having a number average particle diameter of 2 nm to 10 nm. The toner according to any one of the above. When the cross section of the toner is observed,
The toner has a shell structure having a different composition due to a contrast difference,
The toner according to claim 1, wherein an average thickness of the shell structure is 1/60 to 1/10 of the diameter of the toner.   A two-component developer comprising a carrier and the toner according to claim 1.   A toner containing unit containing the toner according to claim 1. An electrostatic latent image carrier, and electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier;
Developing means comprising toner for developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image;
Transfer means for transferring the toner image formed on the electrostatic latent image carrier onto the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium,
An image forming apparatus according to claim 1, wherein the toner is the toner according to claim 1. An electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic latent image carrier;
A developing step of developing the electrostatic latent image formed on the electrostatic latent image carrier with toner to form a toner image;
A transfer step of transferring a toner image formed on the electrostatic latent image carrier onto the surface of a recording medium;
Fixing the toner image transferred to the surface of the recording medium,
6. The image forming method according to claim 1, wherein the toner is the toner according to claim 1.