JP2012198422A - Carrier for electrostatic latent image development, developer for electrostatic latent image development, developer cartridge, image forming apparatus, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress granular unevenness of an image formed on a carrier.SOLUTION: A carrier for electrostatic latent image development has a core material having a binder resin containing a magnetic material and surface roughness Ra of 0.3 μm or more and 0.5 μm or less, and a resin layer that covers the surface of the core material and contains resin.

Description

  The present invention relates to an electrostatic latent image developing carrier, an electrostatic latent image developing developer, a developer cartridge, an image forming apparatus, and a process cartridge.

As a representative method of a so-called two-component developer formed by mixing a carrier for electrostatic image development and a toner among many known development methods of a developer in electrophotographic image formation, The magnetic brush method is mentioned.
In this method, magnetic particles are used as a carrier, a developer composed of toner and a magnetic carrier is held by a magnet, and the developer is formed into a brush shape by the magnetic field of the magnet. By contacting the electrostatic latent image, the toner in the brush is attracted according to the charge amount of the latent image and developed.

As a carrier used in this magnetic brush method, particles having fine irregularities on the surface have been proposed, and the size of the irregularities is preferably 1 μm or more and 20 μm or less (see, for example, Patent Document 1).
In addition, on the spherical particles having magnetism, the outer shell layer provided in a form to cover the particles has irregularities based on fine particles encapsulated in the layer, and the outermost surface is coated with a silicone resin. And the carrier whose average height difference of the said unevenness | corrugation is 0.1 micrometer or more and 2.0 micrometers or less is disclosed.

JP-A-5-197212 JP 2002-287431 A

  An object of the present invention is to provide a granularity in an image formed at an image area ratio of 100% in an environment of 28 ° C./85% RH compared to the case where the surface roughness Ra of the core is not 0.3 μm or more and 0.5 μm or less. Sex unevenness is suppressed.

The above object is achieved by the present invention described below.
That is, the invention according to claim 1
A core material containing a magnetic substance in the binder resin and having a surface roughness Ra of 0.3 μm or more and 0.5 μm or less;
A resin layer covering the surface of the core material and containing a resin;
A carrier for developing an electrostatic latent image.

The invention according to claim 2
A particle having a particle size of 0.8 µm or more and 5 µm or less is contained in a region from the surface of the core material to 1/8 D (µm) when the number average particle size of the core material is D (µm). 1. The electrostatic latent image developing carrier according to 1.

The invention according to claim 3
3. The electrostatic latent image developing carrier according to claim 2, wherein a ratio of an area of the particle in a portion protruding from a surface of the core material to a surface area of the core material is 15% or more and 40% or less.

The invention according to claim 4
An electrostatic latent image developing toner;
A binder having a magnetic material in the binder resin and having a surface roughness Ra of 0.3 μm or more and 0.5 μm or less, and a static resin having a resin layer covering the surface of the core material and containing the resin. A carrier for developing an electrostatic latent image;
Is a developer for developing an electrostatic latent image.

The invention according to claim 5
An electrostatic latent image developing toner;
A binder having a magnetic material in the binder resin and having a surface roughness Ra of 0.3 μm or more and 0.5 μm or less, and a static resin having a resin layer covering the surface of the core material and containing the resin. A carrier for developing an electrostatic latent image;
Is a developer cartridge containing a developer for developing an electrostatic latent image.

The invention according to claim 6
An image carrier,
A charging device for charging the surface of the image carrier;
A latent image forming apparatus that forms an electrostatic latent image on the surface of the charged image carrier;
A toner for developing an electrostatic latent image, a core material containing a magnetic substance in a binder resin and having a surface roughness Ra of 0.3 μm to 0.5 μm, and a surface of the core material; And an electrostatic latent image developing developer containing an electrostatic latent image developing carrier having a resin layer containing a resin, and developing the electrostatic latent image in the electrostatic latent image developing developer. A developing device for developing the electrostatic latent image as a toner image with a toner for use;
A transfer device for transferring the toner image formed on the surface of the image carrier to the surface of the transfer target;
An image forming apparatus having

The invention according to claim 7 provides:
An electrostatic latent image developing toner, a core material containing a magnetic substance in a binder resin and having a surface roughness Ra of 0.3 μm or more and 0.5 μm or less, and a surface of the core material, Containing an electrostatic latent image developing carrier having a resin layer containing a resin, and an electrostatic latent image developing developer containing the resin layer,
A process cartridge including a developer holder that holds and conveys the developer for developing an electrostatic latent image.

  According to the first aspect of the present invention, it is formed at an image area ratio of 100% in an environment of 28 ° C./85% RH, compared to the case where the surface roughness Ra of the core material is not 0.3 μm or more and 0.5 μm or less. The unevenness of graininess in the printed image is suppressed.

  According to the invention of claim 2, when the number average particle diameter of the core material is D (μm), the particle diameter is 0.8 μm or more and 5 μm in the region from the surface of the core material to 1/8 D (μm). Compared with the case where the following particles are not contained, initial graininess unevenness in an image formed with an image area ratio of 100% under an environment of 28 ° C./85% RH is further suppressed.

  According to the invention of claim 3, the ratio of the area of the particles protruding from the surface of the core to the surface area of the core is not less than 15% and not more than 40%, compared with 28 ° C./85% RH. In such an environment, unevenness in graininess over time in an image formed with an image area ratio of 100% is suppressed.

  According to the fourth aspect of the present invention, the surface roughness Ra of the core material in the electrostatic latent image developing carrier is less than 0.3 μm and not more than 0.5 μm in an environment of 28 ° C./85% RH. Graininess unevenness in an image formed with an image area ratio of 100% is suppressed.

  According to the fifth aspect of the present invention, the surface roughness Ra of the core material in the electrostatic latent image developing carrier is 28 ° C./85% RH compared with a case where the surface roughness Ra is not 0.3 μm or more and 0.5 μm or less. Graininess unevenness in an image formed with an image area ratio of 100% is suppressed.

  According to the sixth aspect of the present invention, the graininess of the electrostatic latent image developing developer is higher than that of the surface roughness Ra of the core material in the electrostatic latent image developing carrier of not less than 0.3 μm and not more than 0.5 μm. An image in which the unevenness is suppressed is obtained.

  According to the seventh aspect of the present invention, the graininess of the electrostatic latent image developing developer in the electrostatic latent image developing carrier is greater than that in the case where the surface roughness Ra of the core material is not 0.3 μm or more and 0.5 μm or less. An image in which the unevenness is suppressed is obtained.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows an example of the process cartridge of this embodiment.

  Hereinafter, embodiments of the present invention will be described in detail.

<Electrostatic latent image developing carrier>
The electrostatic latent image developing carrier according to the present embodiment includes a core material containing a magnetic substance in a binder resin and a surface roughness Ra of 0.3 μm or more and 0.5 μm or less, and a surface of the core material And a resin layer containing a resin.

  The carrier in which the magnetic substance is contained in the binder resin has a structure in which the above-described magnetic brush is formed, and the length of the brush is short and the number of brushes is easily formed. In particular, a carrier having no unevenness on the surface of the carrier has a dense brush structure and is solid under a high toner concentration condition particularly under high temperature and high humidity (hereinafter, “28 ° C./85% RH”). When outputting an image, it is considered that the toner tends to be unevenly distributed in the magnetic brush, and the toner is likely to fly to the image portion as a lump, and as a result, unevenness may occur in graininess in the formed image.

If the surface roughness Ra of the core material is smaller than 0.3 μm, the magnetic brush formed on the surface of the developer holding member that transfers the toner to the image holding member tends to be dense, and the toner tends to slip on the carrier surface. Thus, the uneven distribution of the toner occurs on the surface of the carrier, so that it is considered that the toner is transferred in a lump, particularly when a solid image is formed, and the graininess of the image is uneven. This phenomenon occurs remarkably in an environment where the charge amount is small, such as a high temperature and high humidity environment. On the other hand, if Ra is larger than 0.5 μm, a short and uneven brush is formed in the magnetic brush, and as a result, it is considered that unevenness occurs in the graininess in the formed image.
On the other hand, when the surface roughness Ra of the core material is controlled within the above range, the carrier surface roughness is maintained in a suitable range over a long period of time, and appropriate voids are formed on the carrier surface. Since an appropriate magnetic brush is formed over a long period of time, the toner is transferred from the entire length direction of the magnetic brush and the entire process direction without unevenness, and unevenness in graininess is observed even in a high temperature and high humidity environment. It is assumed that a suppressed image is obtained.
The reason why the surface roughness Ra of the core material is defined as described above, not the roughness of the carrier surface (that is, the surface of the resin layer) in the carrier having the core material and the resin layer, is as follows. That is, if the surface of the resin layer is only roughened, a suitable range of roughness cannot be maintained over a long period of time. If the surface of the core material is roughened to the above range, unevenness in graininess is caused. It is because it discovered that the effect of suppression can be maintained over a long period of time.

(Carrier composition)
The carrier according to the present embodiment includes a core material and a resin layer that covers the core material.
−Core material−
・ Surface roughness Ra of core material
The core material contains a magnetic substance in the binder resin and has a surface roughness Ra of 0.3 μm or more and 0.5 μm or less.
The surface roughness Ra of the core material is more preferably 0.35 μm or more and 0.5 μm or less, and particularly preferably 0.4 μm or more and 0.5 μm or less.

  The surface roughness Ra of the core material is measured by an ultra-depth color 3D shape measuring microscope (VK-9500, Keyence) in accordance with JIS-B0601 (1994).

  The method for controlling the surface roughness Ra of the core material to the above range is not particularly limited, but when the number average particle diameter of the core material is D (μm), 1/8 D from the surface of the core material. It is preferable to contain particles having a specific particle size in a region up to (μm) (hereinafter simply referred to as “the outermost layer”). By containing the above-mentioned particles in the outermost layer, the particles protrude from the surface of the core material to form irregularities, and the surface roughness Ra is achieved.

The number average particle size of the core material is measured by the following method.
30 parts by mass of carrier is added to 70 parts by mass of a mixed liquid of two-part adhesive quick 30 (manufactured by Konishi Co., Ltd.), and further mixed, and left to stand for 48 hours in a 25 ° C. environment to be cured. After the cured embedded material is shaped with a razor, it is cut with an ultramicrotome apparatus (LEICA, URUTRACUT UCT) equipped with a diamond knife SK2035 (manufactured by Sumitomo Electric Industries, Ltd.) (surface exposure). Further, while confirming the smoothness of the cut surface with an optical microscope, cutting is performed until a smooth cut surface is formed, thereby producing a test piece. A cross-sectional image of the test piece is obtained by observing the obtained test piece with a scanning electron microscope. The obtained image is taken into image analysis software WinROOF (manufactured by Mitani Corporation), converted into a monochrome image, and then analyzed to measure the number average particle diameter. The measurement is performed at four locations for one carrier and is an arithmetic average of 50 randomly selected carriers.

-Particles contained in the outermost layer portion of the core material Specifically, the outermost layer portion of the core material preferably contains particles having a particle size of 0.8 µm or more and 5 µm or less, preferably 1.5 µm or more and 5 µm or less. Particles are more preferable, and particles of 1.5 μm or more and 4 μm or less are particularly preferable.
The particle size of the above-mentioned particles contained in the outermost layer portion is obtained by taking the surface of the core material observed with a scanning microscope into image analysis software (WinROOF) and forming a monochrome image, and then measuring the particle size of the largest portion. It is done by.

  By containing particles having a particle size in the above-mentioned range in the outermost layer portion of the core material, the toner and the carrier can be mixed and stirred well in the developing device even under high temperature and high humidity, and the toner on the surface of the carrier It is considered that an image having excellent uniformity is obtained.

  The particles contained in the outermost layer of the core material protrude from the surface of the core material (exposed from the surface of the core material or covered with the resin forming the core material but protruding beyond the core material surface) Included). The ratio of the area of the particles protruding from the surface of the core material to the surface area of the core material (the ratio of the particle protruding portions) is preferably 15% or more and 40% or less. Furthermore, particles of 15% to 35% are more preferable, and particles of 20% to 35% are particularly preferable.

  When the proportion of the particle protrusions is within the above range, the fluidity is ensured even when an image is formed at a high speed by suppressing the decrease in the charge amount even when the image is formed at a high speed. Deterioration is suppressed. On the other hand, by being below the above upper limit value, variation in the distribution of charge amount due to the exposure of the particles to the outermost layer portion with time is suppressed, and deterioration of graininess is suppressed.

  In addition, the measurement of the abundance ratio of the particle protrusions is performed by taking the surface of the core material observed with a scanning microscope into image analysis software (WinROOF) and converting it to a monochrome image, and then the maximum particle size is within the particle size range. This is done by selecting the particles one by one and measuring the area ratio, and the average value of 50 fields of the randomly selected core surface is selected.

  The particles contained in the outermost layer of the core material may be magnetic particles or non-magnetic particles. However, when non-magnetic particles are contained, the proportion of the protrusions of the particles due to the non-magnetic particles becomes too large from the viewpoint of suppressing carrier scattering in a region where an image is formed at a particularly high speed due to a decrease in magnetic force. It is preferable to control so that there is no. Specifically, the ratio of the non-magnetic particles among the magnetic particles and non-magnetic particles contained in the outermost layer portion of the core material is preferably 5% by mass or more and 40% by mass or less. More preferably, it is 7 mass% or more and 30 mass% or less.

  Further, the total content of the magnetic body and the non-magnetic body in the core material is preferably 50% by mass or more and 99% by mass or less, more preferably 60% by mass or more and 99% by mass or less, and 70 It is more desirable that the content is not less than 95% by mass.

-Magnetic particles As the material of the magnetic particles contained in the core material, for example, magnetic metals such as iron, steel, nickel, cobalt, and alloys of these with manganese, chromium, rare earth elements (for example, nickel) -Iron alloys, cobalt-iron alloys, aluminum-iron alloys, etc.), magnetic oxides such as ferrite and magnetite, etc. are applied, and among these, ferrite and magnetite are preferred because of their stable characteristics.

  The particle size of the magnetic particles is desirably 0.01 μm or more and 5 μm or less, more desirably 0.1 μm or more and 2 m or less, and further desirably 0.1 μm or more and 1 μm or less.

Nonmagnetic particles As the material of the nonmagnetic particles contained in the core material, for example, titanium oxide, silica, alumina, zinc oxide, magnesium oxide, hematite and the like are applied.

  The particle size of the non-magnetic particles is preferably 0.8 μm or more and 5 μm or less, more preferably 1.5 μm or more and 5 μm or less, and particularly preferably 1.5 μm or more and 4 μm or less.

-Region in which particles are contained The particles (magnetic particles and / or non-magnetic particles) having a particle size in the above-mentioned range contained in the core material are preferably contained in the outermost layer portion of the core material as much as possible.
The concentration of the particles in the outermost layer portion of the core material is preferably 60% or more, more preferably 70% or more, and particularly preferably 80% or more.

The concentration is measured by the following method.
30 parts by mass of carrier is added to 70 parts by mass of a mixed liquid of two-part adhesive quick 30 (manufactured by Konishi Co., Ltd.), and further mixed, and left to stand for 48 hours in a 25 ° C. environment to be cured. After the cured embedded material is shaped with a razor, it is cut with an ultramicrotome apparatus (LEICA, URUTRACUT UCT) equipped with a diamond knife SK2035 (manufactured by Sumitomo Electric Industries, Ltd.) (surface exposure). Further, while confirming the smoothness of the cut surface with an optical microscope, cutting is performed until a smooth cut surface is formed, thereby producing a test piece. A cross-sectional image of the test piece is obtained by observing the obtained test piece with a scanning electron microscope. The obtained image was imported into image analysis software WinROOF (manufactured by Mitani Shoji Co., Ltd.), and “(total area occupied by particles in the region 1 / 8D from the surface of the core material) / (1 / 8D from the surface of the core material). By calculating “total area of region) × 100”, the density per carrier is calculated. The concentration of the particles is the arithmetic average of 50 randomly selected carriers.
If it is difficult to accurately calculate one carrier in one field of view, increase the magnification and perform the above calculation within the field of view, and perform this calculation at four locations (90 degree intervals) per carrier. The average of the results obtained for is taken as the concentration per carrier. Then, the arithmetic average of the results obtained by similarly measuring 50 randomly selected carriers is finally set as the concentration of the carrier.

-Binder resin As binder resin which comprises a core material, styrene resin, acrylic resin, styrene-acrylic copolymer resin, polyolefin resin, phenol resin, etc. are mentioned.

  Further, the core material may further contain other components, and examples of the other components include a charge control agent and fluorine-containing particles.

・ Manufacturing method of core material
(1) “Melting and kneading method” in which a magnetic material and a binder resin are melt-kneaded using a Banbury mixer, a kneader, etc., cooled, pulverized, and classified (for example, Japanese Patent Publication No. 59-24416, Japanese Patent Publication No. 8) Described in Japanese Patent No. 3679)
(2) “Suspension polymerization method” in which a monomer unit of a binder resin and a magnetic substance are dispersed in a solvent to prepare a suspension, and this suspension is polymerized (for example, JP-A-5-1000049) Described in)
(3) "Spray-drying method" in which a magnetic substance is mixed and dispersed in a resin solution and then spray-dried
(4) “Polymerization method” in which the polymerizable monomer of the binder resin and the magnetic material are mixed, and then the composition is granulated and polymerized (described in Japanese Patent No. 349981)
Any of these methods may be used. In any of the above production methods, the method includes a step of preparing a magnetic material by some means, mixing particles of the magnetic material and a binder resin, and incorporating the magnetic material in the binder resin.

In addition, as a method of including particles (magnetic particles and / or non-magnetic particles) having a particle diameter in the above-described range in the outermost layer portion of the core material, for example, the magnetic content contained in the outermost layer portion of the core material. In addition to the treatment of the body particles or the non-magnetic particles with a prescription different from the magnetic material contained in the core material, in the case of the above (1) “melt kneading method”, during the melt kneading If the means for adding and adhering particles in the latter half of the melt-kneading at low temperature is (2) “suspension polymerization method” and (4) “polymerization method”, polymerization is in progress If the means for adding and attaching the particles in the state before the polymerization is completed is the above (3) `` spray dry method '', means for adding and attaching the particles in the latter half of the spraying can be mentioned. It is done.
In addition, according to these methods, a core material in which the above-mentioned particles are present in the outermost layer portion and a portion containing the particles and a portion not containing the particles are integrally formed (the interface is not confirmed) is obtained. .

-Resin layer-
The carrier according to the present embodiment has a resin layer that covers the surface of the core material and contains a resin.
There is no restriction | limiting in particular as resin which comprises this resin layer, According to the objective, it selects. For example, polyolefin resins such as polyethylene and polypropylene; polyvinyl resins and polyvinylidene resins such as polystyrene, acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether and polyvinyl ketone Vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; straight silicone resin composed of organosiloxane bond or modified product thereof; polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, etc. Fluororesin; Silicone resin; Polyester; Polyurethane; Polycarbonate; Phenol resin; Urea-formaldehyde resin, Mela Down resins, benzoguanamine resins, urea resins, amino resins such as polyamide resins, epoxy resins, resins and the like. Also included are homopolymers of monomers containing cycloalkyl groups, copolymers obtained by polymerizing two or more types of monomers containing cycloalkyl groups, and copolymers of monomers containing cycloalkyl groups and monomers not containing cycloalkyl groups. It is done. These may be used individually by 1 type and may use 2 or more types together.

The resin layer may contain conductive particles in the resin. Here, the conductivity means that the volume resistivity is less than 10 ⁷ Ω · cm.
Examples of the conductive particles include metal particles such as gold, silver and copper, carbon black particles, semiconductive oxide particles such as titanium oxide and zinc oxide, titanium oxide, zinc oxide, barium sulfate, aluminum borate, and titanic acid. Examples thereof include particles in which the surface of potassium powder or the like is covered with tin oxide, carbon black, metal, or the like. These may be used individually by 1 type and may use 2 or more types together. Among these, carbon black particles are desirable.
The type of carbon black is not particularly limited, but carbon black having a DBP oil absorption of 50 ml / 100 g or more and 250 ml / 100 g or less is desirable.

The resin layer may contain a wax. The wax is not particularly limited, and examples thereof include low molecular weight polyolefin wax, carnauba wax, rice wax, candelilla wax, paraffin wax, microcrystal wax, Fischer-Tropsch wax, and solid acid ester wax. Of these, paraffin wax and Fischer-Tropsch wax are particularly desirable.
These may be used individually by 1 type and may use 2 or more types together.

-Formation of resin layer Formation of the resin layer in the carrier which concerns on this embodiment will not be specifically limited if it is a method which can form the carrier of the said structure. For example, a spray method in which a solution in which a resin for coating is dissolved is agitated and dispersed using a stirrer (for example, a sand mill) and a resin layer forming solution is sprayed on the surface of the core material, and the above resin layer forming solution And the core material are mixed in a kneader coater, and then the kneader coater method is used to remove the solvent.

-Resin layer thickness The thickness of the resin layer is not particularly limited, but is preferably 0.1 μm or more and 3.0 μm or less, more preferably 0.2 μm or more and 2.0 μm or less, and 0 .2 μm or more and 1.0 μm or less is particularly preferable.
The thickness of the resin layer is measured by the following method.
30 parts by mass of carrier is added to 70 parts by mass of a mixed liquid of two-part adhesive quick 30 (manufactured by Konishi Co., Ltd.), and further mixed, and left to stand for 48 hours in a 25 ° C. environment to be cured. After the cured embedded material is shaped with a razor, it is cut with an ultramicrotome apparatus (LEICA, URUTRACUT UCT) equipped with a diamond knife SK2035 (manufactured by Sumitomo Electric Industries, Ltd.) (surface exposure). Further, while confirming the smoothness of the cut surface with an optical microscope, cutting is performed until a smooth cut surface is formed, thereby producing a test piece. A cross-sectional image of the test piece is obtained by observing the obtained test piece with a scanning electron microscope. After the obtained image was taken into image analysis software WinROOF (Mitani Corporation) and converted into a monochrome image, the thickness of four resin layers at 90 degree intervals was selected for one randomly selected core material. The measurement is repeated for 50 pieces, and the average value is calculated.

・ Surface roughness Ra of the carrier
The surface roughness Ra of the carrier, that is, the surface roughness Ra of the resin layer constituting the surface is preferably 0.25 μm to 0.4 μm, and more preferably 0.3 μm to 0.4 μm.
The surface roughness Ra of the resin layer is measured by the measurement method for the surface roughness Ra of the core material described above.

<Developer for developing electrostatic latent image>
The developer for developing an electrostatic latent image according to this embodiment is configured as a two-component developer including the carrier and toner according to this embodiment.
Hereinafter, the toner used in the developer for developing an electrostatic latent image according to this embodiment will be described.

(Toner composition)
For the toner used in this embodiment, a known binder resin, various colorants, and the like may be used. Examples of the binder resin in the toner used in the exemplary embodiment include polyester resin, polyolefin resin, copolymer of styrene and acrylic acid or methacrylic acid, polyvinyl chloride, phenol resin, acrylic resin, methacrylic resin, and polyacetic acid. Vinyl, silicone resin, modified polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin, polyether polyol resin, etc. may be used alone. It may be good or may be used together.

  Further, the toner used in the exemplary embodiment may contain a charge control agent and a release agent, and nigrosine, a quaternary ammonium salt, an organometallic complex, a chelate complex, and the like may be used.

  The toner production method is not particularly limited, and any known toner production method such as a pulverization method or a polymerization method may be used.

(External toner additive)
Examples of external additives that are externally added to the toner include silica, titanium oxide, cerium oxide, barium titanate, fluorine particles, and acrylic particles. These may be used alone or in combination. Commercially available products such as TG820 (manufactured by Cabot) and HVK2150 (manufactured by Clariant) may be used as the silica.
In addition, as said external additive, that whose volume average particle diameter is 20 nm or more and 1 micrometer or less is used suitably.

  The mixing ratio (mass ratio) of the carrier and the toner according to this embodiment is preferably in the range of toner: carrier = 1: 100 to 30: 100, and more preferably in the range of 3: 100 to 15: 100.

<Image forming apparatus>
Next, an image forming apparatus according to this embodiment using the developer for developing an electrostatic latent image according to this embodiment will be described.
An image forming apparatus according to the present embodiment includes an image carrier, a charging device that charges the surface of the image carrier, a latent image forming device that forms an electrostatic latent image on the charged surface of the image carrier, A developing device that develops the electrostatic latent image as a toner image with the toner in the developer for developing an electrostatic latent image according to the above-described embodiment, and the toner image formed on the surface of the image holding member. And a transfer device for transferring to the recording medium. The image forming apparatus according to the present embodiment may include other devices such as a cleaning device that cleans residual transfer components by sliding the latent image holding member with a cleaning member as necessary.
Hereinafter, an example of the image forming apparatus according to the present embodiment will be described, but the present invention is not limited thereto. The main parts shown in the figure will be described, and the description of the other parts will be omitted.

  In this image forming apparatus, for example, the part including the developing device may have a cartridge structure (process cartridge) that is detachable from the main body of the image forming apparatus. As the process cartridge, a developer holding member is used. The process cartridge according to the present embodiment, which includes at least the developer for developing an electrostatic latent image according to the present embodiment, is preferably used.

  FIG. 1 is a schematic configuration diagram illustrating a four-tandem color image forming apparatus which is an example of an image forming apparatus according to the present embodiment. The image forming apparatus shown in FIG. 1 is a first to first electrophotographic method that outputs yellow (Y), magenta (M), cyan (C), and black (K) images based on color-separated image data. Fourth image forming units 10Y, 10M, 10C, and 10K (image forming apparatuses) are provided. These image forming units (hereinafter simply referred to as “units”) 10Y, 10M, 10C, and 10K are juxtaposed at a predetermined distance from each other. The units 10Y, 10M, 10C, and 10K may be process cartridges that are detachable from the main body of the image forming apparatus.

Above each of the units 10Y, 10M, 10C, and 10K, an intermediate transfer belt 20 as an intermediate transfer member is extended through each unit. The intermediate transfer belt 20 is provided by being wound around a driving roller 22 and a support roller 24 that are in contact with the inner surface of the intermediate transfer belt 20 that are spaced apart from each other from the left to the right in the drawing. It is designed to travel in the direction toward 10K. Further, an intermediate transfer member cleaning device 30 is provided on the side of the image carrier of the intermediate transfer belt 20 so as to face the driving roller 22.
Further, each of the developing devices (developing devices) 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K includes yellow, magenta, cyan, and black contained in the toner cartridges 8Y, 8M, 8C, and 8K. The four colors of toner are supplied.

  Since the first to fourth units 10Y, 10M, 10C, and 10K described above have the same configuration, here, the first unit that forms a yellow image disposed on the upstream side in the intermediate transfer belt traveling direction. 10Y will be described as a representative. Note that the second to fourth units are denoted by reference numerals with magenta (M), cyan (C), and black (K) instead of yellow (Y) in the same parts as the first unit 10Y. Description of 10M, 10C, 10K is omitted.

The first unit 10Y has a photoreceptor 1Y that functions as a latent image holding member. Around the photosensitive member 1Y, a charging roller 2Y for charging the surface of the photosensitive member 1Y to a predetermined potential, and the charged surface is exposed by a laser beam 3Y based on a color-separated image signal to form an electrostatic latent image. An exposure device 3 to be formed, a developing device (developing device) 4Y for supplying a charged toner to the electrostatic latent image to develop the electrostatic latent image, and a primary transfer roller for transferring the developed toner image onto the intermediate transfer belt 20 A 5Y (primary transfer device) and a photoconductor cleaning device (cleaning device) 6Y for removing toner remaining on the surface of the photoconductor 1Y after the primary transfer are sequentially arranged.
The primary transfer roller 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. Further, a bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rollers 5Y, 5M, 5C, and 5K. Each bias power source varies the transfer bias applied to each primary transfer roller under the control of a control unit (not shown).

Hereinafter, an operation of forming a yellow image in the first unit 10Y will be described. First, prior to operation, the surface of the photoreceptor 1Y is charged to a potential of −600V to −800V by the charging roller 2Y.
The photoreceptor 1Y is formed by laminating a photosensitive layer on a conductive substrate (volume resistivity at 20 ° C .: 1 × 10 ⁻⁶ Ωcm or less). This photosensitive layer usually has a high resistance (a resistance equivalent to that of a general resin), but has a property that the specific resistance of the portion irradiated with the laser beam changes when irradiated with the laser beam 3Y. Therefore, a laser beam 3Y is output to the surface of the charged photoreceptor 1Y via the exposure device 3 in accordance with yellow image data sent from a control unit (not shown). The laser beam 3Y is applied to the photosensitive layer on the surface of the photoreceptor 1Y, whereby an electrostatic latent image of a yellow print pattern is formed on the surface of the photoreceptor 1Y.

The electrostatic latent image is an image formed on the surface of the photoreceptor 1Y by charging, and the specific resistance of the irradiated portion of the photosensitive layer is lowered by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y is reduced. On the other hand, it is a so-called negative latent image formed by the charge remaining in the portion not irradiated with the laser beam 3Y.
The electrostatic latent image formed on the photoreceptor 1Y in this way is rotated to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic latent image on the photoreceptor 1Y is converted into a visible image (toner image) by the developing device 4Y.

  Yellow toner is accommodated in the developing device 4Y. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charged charge on the photoreceptor 1Y, and a developer roll (developer holder). Is held on. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner is electrostatically attached to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. . The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer, a predetermined primary transfer bias is applied to the primary transfer roller 5Y, and the electrostatic force directed from the photoreceptor 1Y to the primary transfer roller 5Y generates toner. By acting on the image, the toner image on the photoreceptor 1 </ b> Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time is a (+) polarity opposite to the polarity (−) of the toner. For example, in the first unit 10Y, it is controlled to about +10 μA by a control unit (not shown).
On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by the cleaning device 6Y.

Further, the primary transfer bias applied to the primary transfer rollers 5M, 5C, and 5K after the second unit 10M is also controlled according to the first unit.
Thus, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of the respective colors are superimposed and transferred in a multiple manner.

  The intermediate transfer belt 20 onto which the four color toner images have been transferred through the first to fourth units is arranged on the image transfer surface side of the intermediate transfer belt 20 and the support roller 24 in contact with the inner surface of the intermediate transfer belt 20. The secondary transfer roller (secondary transfer device) 26 is connected to a secondary transfer portion. On the other hand, a recording paper (transfer object) P is fed at a predetermined timing into a gap where the secondary transfer roller 26 and the intermediate transfer belt 20 are pressed against each other via a supply mechanism, and a predetermined secondary transfer bias is provided. Is applied to the support roller 24. The transfer bias applied at this time is a (−) polarity that is the same polarity as the polarity (−) of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P is applied to the toner image, and the transfer bias is applied to the intermediate transfer belt 20. The toner image is transferred onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection device (not shown) for detecting the resistance of the secondary transfer portion, and is voltage-controlled.

Thereafter, the recording paper P is fed into the fixing device 28, the toner image is heated, and the color-superposed toner image is melted and fixed on the recording paper P. The recording paper P on which the color image has been fixed is carried out toward the discharge unit, and a series of color image forming operations is completed.
The image forming apparatus exemplified above is configured to transfer the toner image onto the recording paper P via the intermediate transfer belt 20, but the present invention is not limited to this configuration, and the toner image is directly transferred from the photoconductor. It may be a structure that is transferred to a recording sheet.

<Process cartridge>
FIG. 2 is a schematic configuration diagram showing a preferred example of a process cartridge containing a developer for developing an electrostatic latent image according to the present embodiment. In the process cartridge 200, a charging roller 108, a developing device 111, a photoconductor cleaning device (cleaning device) 113, an opening 118 for exposure, and an opening 117 for static elimination exposure are attached to a rail 116 together with the photoconductor 107. Are combined and integrated with each other. In FIG. 2, reference numeral 300 represents a transfer object.
The process cartridge 200 is detachable from an image forming apparatus main body including a transfer device 112, a fixing device 115, and other components (not shown). It forms a forming apparatus.

  The process cartridge shown in FIG. 2 includes a photosensitive member 107, a charging roller 108, a developing device 111, a cleaning device 113, an opening 118 for exposure, and an opening 117 for static elimination exposure. May be selectively combined. In the process cartridge according to the present embodiment, in addition to the developing device 111, the photoconductor 107, the charging roller 108, the photoconductor cleaning device (cleaning device) 113, the opening 118 for exposure, and the charge removal exposure. You may provide at least 1 sort (s) selected from the group comprised from the opening part 117. FIG.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited by the following Example. In the following, “part” and “%” are “mass basis” unless otherwise indicated.

[Example 1]
<Creation of carrier>
(1) Formation of core material The core material was formed with the following method.
[Preparation of magnetic particles A]
By adding 500 parts of magnetite particles having an average particle diameter of 0.27 μm to a Henschel mixer and stirring sufficiently, adding 5.0 parts of a silane coupling agent, raising the temperature to 100 ° C., and thoroughly stirring and mixing for 30 minutes Magnetite magnetic particles A coated with a silane coupling agent were obtained.

[Preparation of magnetic particles B]
By adding 100 parts of magnetite particles having an average particle diameter of 0.7 μm to a Henschel mixer and stirring sufficiently, 0.03 part of a silane coupling agent is added, the temperature is raised to 100 ° C., and the mixture is thoroughly stirred for 30 minutes. Magnetite magnetic particles B coated with a silane coupling agent were obtained.

[Preparation of Core Particle (1)]
Next, 60 parts of phenol, 90 parts of 37% formalin, 420 parts of the above magnetic particles A lipophilically treated, 16 parts of 28% aqueous ammonia, and 40 parts of water were stirred and mixed in a 1 L four-necked flask. Next, after raising the temperature to 45 ° C. over 30 minutes with stirring, the rotational speed of the stirring blade is decreased while watching the inside of the flask, and after adding 7 parts of the magnetic particles B and 10 parts of water, the addition is completed. The number of revolutions was again increased to the initial number of revolutions, the temperature was raised to 85 ° C. in 30 minutes, and the reaction was performed at the same temperature for 180 minutes. After cooling to 25 ° C. and adding 500 ml of water, the supernatant was removed and the precipitate was washed with water. This was air-dried under reduced pressure to obtain core material particles (1).

  The surface roughness Ra of the core material, the particle size range of the particles contained in the outermost layer portion (outermost layer portion particle size range), the concentration of the particles in the outermost layer portion (outermost layer particle concentration), and the particle protrusion Table 1 shows the results of measuring the ratio of parts present.

(2) Formation of resin layer A resin layer was formed on the surface of the core material by the following method.
[Preparation of coating layer forming raw material solution (a)]
Components of the following composition were stirred / dispersed with a stirrer for 60 minutes to prepare a coating layer forming raw material solution (a).
Toluene: 85 parts Styrene-methacrylate copolymer (mass ratio 90:10): 12 parts Carbon black (R330, manufactured by Cabot): 4 parts

[Production of Carrier 1]
100 parts of the core material particles (1) and 12 parts of the coating layer forming raw material solution (a) are put into a vacuum degassing type kneader, and while stirring, the pressure is reduced to −200 mmHg at 60 ° C. and mixed for 15 minutes. It was warmed / depressurized and stirred and dried at 94 ° C./−720 mmHg for 30 minutes to obtain resin-coated particles. Next, sieving was performed with a 75 μm mesh sieving net to obtain Carrier 1.
Table 1 shows the results of measuring the surface roughness Ra of the resin layer.

<Production of toner>
Extruder is a mixture of 100 parts of styrene-butyl acrylate copolymer (weight average molecular weight Mw = 150,000, copolymerization ratio 80:20), 5 parts of carbon black (Mogal L: manufactured by Cabot Corporation), and 6 parts of carnauba wax. After kneading with a jet mill, spheronization with hot air was performed with Kryptron (manufactured by Kawasaki Heavy Industries) and classified with an air classifier to obtain toner particles having a particle size of 6.2 μm. To 100 parts of the toner particles, 1.2 parts of colloidal silica (R972 manufactured by Nippon Aerosil Co., Ltd.) and 0.3 parts of colloidal silica having a particle size of 0.6 μm are added and mixed with a Henschel mixer to add external toner particles. Obtained.

<Production of developer>
The developer was prepared by stirring 85 parts of the carrier and 15 parts of the toner in a V-type blender for 20 minutes.

[Example 2]
In Example 1, a developer was prepared by the method described in Example 1 except that the carrier 1 was changed to the following.
(Preparation of carrier 2)
Core material particles (2) were prepared by the method described in Example 1, except that in the preparation of the core material particles (1) of Example 1, the addition amount of the magnetic particles B was changed to 10 parts.
Moreover, in preparation of the carrier 1 of Example 1, Example 1 except using the said core material particle (2) as a core material particle, and changing the addition amount of the raw material solution (a) for coating layer formation into 14 parts. Carrier 2 was obtained by the method described in 1.

[Example 3]
In Example 1, a developer was prepared by the method described in Example 1 except that the carrier 1 was changed to the following.
(Preparation of carrier 3)
In the production of the magnetic particles B of Example 1, the magnetite particles having an average particle size of 0.7 μm were changed to an average particle size of 0.8 μm, and the amount of the magnetic particles B added in the production of the core particles (1) The core particle (3) was produced by the method described in Example 1 except that the amount was changed to 13 parts.
Moreover, the said core material particle (3) was used as a core material particle, and preparation of the carrier was performed by the method as described in preparation of the said carrier 2, and the carrier 3 was obtained.

[Example 4]
In Example 1, a developer was prepared by the method described in Example 1 except that the carrier 1 was changed to the following.
(Preparation of carrier 4)
In the production of the magnetic particles B of Example 1, the magnetite particles having an average particle size of 0.7 μm were changed to an average particle size of 0.8 μm, and the amount of the magnetic particles B added in the production of the core particles (1) The core particle (4) was produced by the method described in Example 1 except that the amount was changed to 12 parts.
Moreover, the said core material particle (4) was used as a core material particle, and preparation of a carrier was performed by the method as described in preparation of the said carrier 2, and the carrier 4 was obtained.

[Example 5]
In Example 1, a developer was prepared by the method described in Example 1 except that the carrier 1 was changed to the following.
(Preparation of carrier 5)
In the production of the magnetic particles B of Example 1, the magnetite particles having an average particle size of 0.7 μm were changed to an average particle size of 1.5 μm, and the amount of the magnetic particles B added in the production of the core particles (1) A core particle (5) was produced by the method described in Example 1 except that was changed to 15 parts.
Moreover, the said core material particle (5) was used as a core material particle, and preparation of the carrier was performed by the method as described in preparation of the said carrier 2, and the carrier 5 was obtained.

[Example 6]
In Example 1, a developer was prepared by the method described in Example 1 except that the carrier 1 was changed to the following.
(Preparation of carrier 6)
In the production of the magnetic particles B of Example 1, the magnetite particles having an average particle size of 0.7 μm were changed to an average particle size of 4 μm, and in the production of the core material particles (1), the addition amount of the magnetic particles B was 15 Core material particles (6) were produced by the method described in Example 1 except that the part was changed to the part.
Moreover, the said core material particle (6) was used as a core material particle, and preparation of the carrier was performed by the method as described in preparation of the said carrier 2, and the carrier 6 was obtained.

[Example 7]
In Example 1, a developer was prepared by the method described in Example 1 except that the carrier 1 was changed to the following.
(Preparation of carrier 7)
In the production of the magnetic particles B of Example 1, the magnetite particles having an average particle size of 0.7 μm were changed to an average particle size of 2.0 μm, and the amount of the magnetic particles B added in the production of the core particles (1) A core particle (7) was produced by the method described in Example 1 except that the amount was changed to 15 parts.
Moreover, the said core material particle (7) was used as a core material particle, and preparation of the carrier was performed by the method as described in preparation of the said carrier 2, and the carrier 7 was obtained.

[Example 8]
In Example 1, a developer was prepared by the method described in Example 1 except that the carrier 1 was changed to the following.
(Preparation of carrier 8)
In the production of the magnetic particles B of Example 1, the magnetite particles having an average particle size of 0.7 μm were changed to an average particle size of 1.7 μm, and the amount of the magnetic particles B added in the production of the core particles (1) A core particle (8) was produced by the method described in Example 1 except that the amount was changed to 15 parts.
Moreover, the said core material particle (8) was used as a core material particle, and carrier preparation was performed by the method as described in preparation of the said carrier 2, and the carrier 8 was obtained.

[Example 9]
In Example 1, a developer was prepared by the method described in Example 1 except that the carrier 1 was changed to the following.
(Preparation of carrier 9)
In the production of the magnetic particles B of Example 1, the magnetite particles having an average particle size of 0.7 μm were changed to an average particle size of 1.3 μm, and the amount of the magnetic particles B added in the production of the core particles (1) A core particle (9) was produced by the method described in Example 1 except that was changed to 17 parts.
Moreover, the said core material particle (9) was used as a core material particle, and preparation of a carrier was performed by the method as described in preparation of the said carrier 2, and the carrier 9 was obtained.

[Example 10]
In Example 1, a developer was prepared by the method described in Example 1 except that the carrier 1 was changed to the following.
(Preparation of carrier 10)
In the production of the magnetic particles B of Example 1, the magnetite particles having an average particle size of 0.7 μm are changed to an average particle size of 5.5 μm, and the amount of the magnetic particles B added in the production of the core particles (1) A core particle (10) was produced by the method described in Example 1 except that the amount was changed to 15 parts.
Moreover, the said core material particle (10) was used as a core material particle, and preparation of a carrier was performed by the method as described in preparation of the said carrier 2, and the carrier 10 was obtained.

[Comparative Example 1]
In Example 1, a developer was prepared by the method described in Example 1 except that the carrier 1 was changed to the following.
(Preparation of carrier 11)
In the production of the magnetic particles B of Example 1, the magnetite particles having an average particle size of 0.7 μm were changed to an average particle size of 0.3 μm, and the amount of the magnetic particles B added in the production of the core material particles (1) Core material particles (11) were produced by the method described in Example 1 except that the amount was changed to 10 parts.
Moreover, the said core material particle (11) was used as a core material particle, and preparation of the carrier was performed by the method as described in preparation of the said carrier 1, and the carrier 11 was obtained.

[Comparative Example 2]
In Example 1, a developer was prepared by the method described in Example 1 except that the carrier 1 was changed to the following.
(Preparation of carrier 12)
In the production of the magnetic particles B of Example 1, the magnetite particles having an average particle size of 0.7 μm were changed to an average particle size of 0.6 μm, and the amount of the magnetic particles B added in the production of the core particles (1) Core material particles (12) were produced by the method described in Example 1 except that the amount was changed to 10 parts.
Moreover, the said core material particle (12) was used as a core material particle, and preparation of the carrier was performed by the method as described in preparation of the said carrier 2, and the carrier 12 was obtained.

[Comparative Example 3]
In Example 1, a developer was prepared by the method described in Example 1 except that the carrier 1 was changed to the following.
(Preparation of carrier 13)
Fe ₂ O ₃ : 500 parts, Mn (OH) ₂ : 222 parts, Mg (OH) ₂ : 36 parts are mixed, pulverized with a dispersing agent, water and zirconia beads having a media diameter of 1 mm, filtered and then dried. The temperature was raised to 900 ° C. to obtain an oxide. Subsequently, a dispersing agent and water were added, and it mixed / pulverized for 10 hours with the wet ball mill. Next, after granulating and drying with a spray dryer, the temperature was set to 1150 ° C. with an electric furnace and firing was performed for 4.5 hours. Core material particles (13) were obtained through the crushing step and the classification step.
Moreover, the said core material particle (13) was used as a core material particle, and carrier preparation was performed by the method as described in preparation of the said carrier 2, and the carrier 13 was obtained.

<Evaluation test>
-Evaluation of graininess at initial stage and time-
Using each developer, 10000 sheets of an image area ratio of 100% were continuously output in a high temperature and high humidity (28 ° C./85% RH) environment using a Docu Center Color 400 manufactured by Fuji Xerox Co., Ltd. The tenth and 10000th images of the output images were visually observed to evaluate the graininess. Specific evaluation criteria are as follows. In addition, 4, 3, and 2 were made into the tolerance | permissible_range.
4: Unevenness in graininess cannot be confirmed at the visual level and is very good 3: Unevenness in the graininess is almost unobservable at the visual level 2: Some unevenness in graininess can be confirmed at the visual level Good thing 1: Graininess is uneven and bad at visual level

1Y, 1M, 1C, 1K, 107 photoconductor (latent image holder)
2Y, 2M, 2C, 2K, 108 Charging roller 3Y, 3M, 3C, 3K Laser beam 3 Exposure device 4Y, 4M, 4C, 4K, 111 Developing device 5Y, 5M, 5C, 5K Primary transfer roller 6Y, 6M, 6C , 6K, 113 Photoconductor cleaning device 8Y, 8M, 8C, 8K Toner cartridge 10Y, 10M, 10C, 10K Image forming unit 20 Intermediate transfer belt 22 Drive roller 24 Support roller 26 Secondary transfer roller 28, 115 Fixing device 30 Intermediate transfer Body cleaning device 112 Transfer device 116 Mounting rail 117 Opening portion 118 for static elimination exposure Opening portion 200 for exposure Process cartridge P, 300 Recording paper (transferred material)

Claims (7)

A core material containing a magnetic substance in the binder resin and having a surface roughness Ra of 0.3 μm or more and 0.5 μm or less;
A resin layer covering the surface of the core material and containing a resin;
A carrier for developing an electrostatic latent image.   A particle having a particle size of 0.8 µm or more and 5 µm or less is contained in a region from the surface of the core material to 1/8 D (µm) when the number average particle size of the core material is D (µm). 2. The carrier for developing an electrostatic latent image according to 1.   The carrier for developing an electrostatic latent image according to claim 2, wherein a ratio of an area of the particle in a portion protruding from a surface of the core material to a surface area of the core material is 15% or more and 40% or less. An electrostatic latent image developing toner;
A binder having a magnetic material in the binder resin and having a surface roughness Ra of 0.3 μm or more and 0.5 μm or less, and a static resin having a resin layer covering the surface of the core material and containing the resin. A carrier for developing an electrostatic latent image;
A developer for developing an electrostatic latent image. An electrostatic latent image developing toner;
A binder having a magnetic material in the binder resin and having a surface roughness Ra of 0.3 μm or more and 0.5 μm or less, and a static resin having a resin layer covering the surface of the core material and containing the resin. A carrier for developing an electrostatic latent image;
A developer cartridge containing a developer for developing an electrostatic latent image. An image carrier,
A charging device for charging the surface of the image carrier;
A latent image forming apparatus that forms an electrostatic latent image on the surface of the charged image carrier;
A toner for developing an electrostatic latent image, a core material containing a magnetic substance in a binder resin and having a surface roughness Ra of 0.3 μm to 0.5 μm, and a surface of the core material; And an electrostatic latent image developing developer containing an electrostatic latent image developing carrier having a resin layer containing a resin, and developing the electrostatic latent image in the electrostatic latent image developing developer. A developing device for developing the electrostatic latent image as a toner image with a toner for use;
A transfer device for transferring the toner image formed on the surface of the image carrier to the surface of the transfer target;
An image forming apparatus. An electrostatic latent image developing toner, a core material containing a magnetic substance in a binder resin and having a surface roughness Ra of 0.3 μm or more and 0.5 μm or less, and a surface of the core material, Containing an electrostatic latent image developing carrier having a resin layer containing a resin, and an electrostatic latent image developing developer containing the resin layer,
A process cartridge comprising a developer holder that holds and conveys the developer for developing an electrostatic latent image.