Electrophotographic device

Abstract

To provide an electrophotographic device that further reduces white dots and image streaks due to toner fusion and slipping of a toner external additive.SOLUTION: In an electrophotographic device, the content of a compound represented by the general formula (1) is 10 mass% or more and 50 mass% or less relative to the total of the content of the compound represented by the general formula (1) and the content of a compound represented by the general formula (2). A surface of a surface layer has a maximum height roughness Rmax of 0.30 μm or less, which is defined by JISB0601:1982.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electrophotographic apparatus. [Background technology]

[0002] Electrophotographic photoreceptors containing organic photoconductive materials (charge-generating materials) are widely used in electrophotographic devices. In recent years, there has been a demand for improved mechanical durability (wear resistance) and cleaning properties of electrophotographic photoreceptors in order to extend their lifespan and improve image quality during repeated use.

[0003] As a technique for improving the abrasion resistance and cleaning properties of an electrophotographic photosensitive member, Patent Document 1 discloses a technique for improving abrasion resistance, scratch resistance, and cleaning properties by incorporating metal oxide particles that have been surface-modified with a silicone surface modifier onto the surface of an electrophotographic photosensitive member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-67781 Summary of the Invention [Problem to be solved by the invention]

[0005] In the technology described in Patent Document 1, when the image is repeatedly used in a high-humidity environment, toner melting occurs on the surface of the electrophotographic photosensitive member, and toner external additives slip through, which can result in white spots (parts where toner should adhere but does not adhere, leaving them white) and image streaks (for example, linear or band-like streaks running in the direction of image formation). SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an electrophotographic apparatus in which white spots and image streaks caused by toner fusion and slip-through of toner external additives are further suppressed. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides: an electrophotographic photoreceptor; a charging means for charging the surface of the electrophotographic photosensitive member; an image exposure means for irradiating the surface of the electrophotographic photosensitive member with image exposure light to form an electrostatic latent image on the surface of the electrophotographic photosensitive member; a developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member using a two-component developer having a toner and a magnetic carrier to form a toner image on the surface of the electrophotographic photosensitive member; a cleaning means for cleaning residual toner from the surface of the electrophotographic photosensitive member; a transfer means for transferring the toner image formed on the surface of the electrophotographic photosensitive member onto a recording medium; An electrophotographic apparatus having The electrophotographic photoreceptor has a surface layer having a copolymer of a composition containing a compound represented by the following general formula (1) and a compound represented by the following general formula (2), The content of the compound represented by the following general formula (1) in the composition is 10% by mass or more and 50% by mass or less with respect to the total content of the compound represented by the general formula (1) and the compound represented by the general formula (2), The surface of the surface layer has a maximum height roughness Rmax of 0.30 μm or less as specified in JIS B0601:1982. The electrophotographic apparatus is characterized by: [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an electrophotographic apparatus in which white spots and image streaks caused by toner fusion and external additive slip-through are improved. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of the configuration of an electrophotographic apparatus. [Figure 2] FIG. 1 is a schematic diagram showing an example of a solid-state exposure apparatus. [Figure 3] FIG. 2 is a schematic diagram illustrating the crown shape of a charging roller. [Figure 4] FIG. 2 is a schematic diagram illustrating an example of a developing unit and a toner supply device. [Figure 5] FIG. 2 is a diagram illustrating an example of a toner surface treatment device. [Figure 6] FIG. 4 is a schematic diagram showing the penetration amount of a cleaning blade. DETAILED DESCRIPTION OF THE INVENTION

[0009] <One embodiment> One embodiment of the present invention is directed to an electrophotographic device. The electrophotographic apparatus of the present invention comprises: an electrophotographic photoreceptor; a charging means for charging the surface of the electrophotographic photosensitive member; an image exposure means for irradiating the surface of the electrophotographic photosensitive member with image exposure light to form an electrostatic latent image on the surface of the electrophotographic photosensitive member; a developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member using a two-component developer having a toner and a magnetic carrier to form a toner image on the surface of the electrophotographic photosensitive member; a cleaning means for cleaning residual toner from the surface of the electrophotographic photosensitive member; a transfer means for transferring the toner image formed on the surface of the electrophotographic photosensitive member onto a recording medium; An electrophotographic apparatus having The electrophotographic photoreceptor has a surface layer having a copolymer of a composition containing a compound represented by the following general formula (1) and a compound represented by the following general formula (2), The content of the compound represented by the following general formula (1) in the composition is 10% by mass or more and 50% by mass or less with respect to the total content of the compound represented by the general formula (1) and the compound represented by the general formula (2), The surface of the surface layer is characterized in that the maximum height roughness Rmax defined in JIS B0601:1982 is 0.30 μm or less. The following describes the embodiments.

[0010] In the electrophotographic device of the present invention, the content of the compound represented by the following general formula (1) in the composition is 10% by mass or more and 50% by mass or less relative to the total content of the compound represented by the following general formula (1) and the compound represented by the following general formula (2), thereby reducing the crosslink density in the film and increasing the amount of wear on the surface of the electrophotographic photoreceptor. When the amount of wear increases, the external additive becomes less likely to adhere to the surface of the electrophotographic photoreceptor, thereby suppressing fusion. [ka] (In general formula (1), R1, R2, R3, and R4 each represent hydrogen or a methyl group. p represents an integer of 2 or more and 5 or less. p is preferably an integer of 2 or more and 3 or less.) [ka] (In general formula (2), R5 and R6 each represent hydrogen or a methyl group. q represents an integer of 2 or more and 5 or less. q is preferably an integer of 2 or more and 3 or less.)

[0011] At the same time, when a two-component developer is used, the magnetic carrier comes into contact with the surface of the electrophotographic photosensitive member, causing unevenness on the surface. It is believed that the unevenness reduces the torque on the surface. Also, by making Rmax 0.3 μm or less, it becomes difficult for toner to slip through. It is believed that the above-mentioned configuration can suppress toner fusion and toner slip-through.

[0012] Specific examples of the compound represented by general formula (1) include compounds represented by the following formulae (1-1) to (1-10). [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka]

[0013] Specific examples of the compound represented by general formula (2) include compounds represented by the following formulae (2-1) to (2-6). [ka] [ka] [ka] [ka] [ka] [ka]

[0014] [Electrophotographic photoreceptor] As a method for producing an electrophotographic photoreceptor, a method of preparing a coating liquid for each layer described later, coating each coating liquid in a desired layer order, and drying can be mentioned. Examples of the coating method for the coating liquid include dip coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, and ring coating. From the viewpoint of efficiency and productivity, dip coating is preferred. The shape of the electrophotographic photoreceptor is preferably cylindrical.

[0015] <Support> The support is preferably conductive (conductive support). The support is preferably cylindrical. The surface of the support may be subjected to electrochemical treatment such as anodization, blasting, cutting, etc. The support is preferably made of metal, resin, or glass. Examples of metals include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. Among these, an aluminum support using aluminum is preferred. Alternatively, conductivity may be imparted to resin or glass by mixing or coating the resin or glass with a conductive material.

[0016] <Conductive layer> A conductive layer may be provided on the support, which can conceal scratches and irregularities on the surface of the support and control light reflection on the surface of the support. The conductive layer preferably contains conductive particles and a binder resin.

[0017] Examples of materials for the conductive particles include metal oxide particles, metal particles, carbon black, etc. Examples of metal oxide particles include particles of zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, bismuth oxide, etc. Examples of metal particles include particles of aluminum, nickel, iron, nichrome, copper, zinc, silver, etc.

[0018] Among these, metal oxide particles are preferred, and particles of titanium oxide, tin oxide, and zinc oxide are particularly preferred. The surfaces of the metal oxide particles may be treated with a silane coupling agent or the like, or the metal oxide particles may be doped with elements such as phosphorus or aluminum or their oxides.

[0019] The conductive particles may also have a laminated structure having a core particle and a coating layer covering the particle. Examples of the core particle include particles of titanium oxide, barium sulfate, and zinc oxide. Examples of the coating layer include metal oxides such as tin oxide. When metal oxide particles are used as the conductive particles, their volume average particle size is preferably 1 nm or more and 500 nm or less, and more preferably 3 nm or more and 400 nm or less.

[0020] Examples of the binder resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, and alkyd resin.

[0021] The conductive layer may further contain silicone oil, resin particles, a masking agent such as titanium oxide, and the like. The average thickness of the conductive layer is preferably 1 μm or more and 50 μm or less, and more preferably 3 μm or more and 40 μm or less.

[0022] The conductive layer can be formed by preparing a coating solution for the conductive layer containing the above-mentioned materials and solvent, forming a coating film from this, and drying and / or curing it. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Methods for dispersing conductive particles in the coating solution for the conductive layer include methods using a paint shaker, sand mill, ball mill, or liquid collision-type high-speed disperser.

[0023] <Undercoat layer> An undercoat layer may be provided on the support or the conductive layer, which can improve adhesion between layers and provide a charge injection blocking function. The undercoat layer preferably contains a binder resin. Alternatively, the undercoat layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group.

[0024] Examples of binder resins include polyester resins, polycarbonate resins, polyvinyl acetal resins, acrylic resins, epoxy resins, melamine resins, polyurethane resins, phenol resins, polyvinylphenol resins, alkyd resins, polyvinyl alcohol resins, polyethylene oxide resins, polypropylene oxide resins, polyamide resins, polyamic acid resins, polyimide resins, polyamideimide resins, and cellulose resins.

[0025] Examples of the polymerizable functional group contained in the monomer having a polymerizable functional group include an isocyanate group, a blocked isocyanate group, a methylol group, an alkylated methylol group, an epoxy group, a metal alkoxide group, a hydroxy group, an amino group, a carboxy group, a thiol group, a carboxylic acid anhydride group, and a carbon-carbon double bond group.

[0026] The undercoat layer may further contain an electron transport material, metal oxide particles, metal particles, or a conductive polymer for the purpose of improving electrical properties. Among these, the use of an electron transport material and metal oxide particles is preferred.

[0027] Examples of the electron transport substance include a quinone compound, an imide compound, a benzimidazole compound, a cyclopentadienylidene compound, a fluorenone compound, a xanthone compound, a benzophenone compound, a cyanovinyl compound, an aryl halide compound, a silole compound, a boron-containing compound, etc. An electron transport substance having a polymerizable functional group may be used as the electron transport substance, and the undercoat layer may be formed as a cured film by copolymerizing the electron transport substance with the above-mentioned monomer having the polymerizable functional group.

[0028] Examples of metal oxide particles include particles of indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, silicon dioxide, etc. Examples of metal particles include particles of gold, silver, aluminum, etc.

[0029] The undercoat layer may further contain additives. The average thickness of the undercoat layer is preferably from 0.1 μm to 50 μm, more preferably from 0.2 μm to 40 μm, and particularly preferably from 0.3 μm to 30 μm.

[0030] The undercoat layer can be formed by preparing a coating solution for the undercoat layer containing the above-mentioned materials and solvent, forming a coating film from the coating solution, and drying and / or curing the coating film. Examples of the solvent used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0031] <Photosensitive layer> The photosensitive layer of an electrophotographic photoreceptor is mainly classified into (1) a multi-layer type photosensitive layer and (2) a single-layer type photosensitive layer. (1) The multi-layer type photosensitive layer has a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. (2) The single-layer type photosensitive layer has a photosensitive layer containing both a charge generation material and a charge transport material.

[0032] (1) Laminated photosensitive layer The laminated photosensitive layer has a charge generating layer and a charge transport layer. (1-1) Charge generation layer The charge generating layer preferably contains a charge generating substance and a binder resin. Examples of charge-generating materials include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, and phthalocyanine pigments. Among these, azo pigments and phthalocyanine pigments are preferred. Among phthalocyanine pigments, oxytitanium phthalocyanine pigments, chlorogallium phthalocyanine pigments, and hydroxygallium phthalocyanine pigments are preferred. The content of the charge generating material in the charge generating layer is preferably 40% by mass or more and 85% by mass or less, and more preferably 60% by mass or more and 80% by mass or less, based on the total mass of the charge generating layer.

[0033] Examples of binder resins include polyester resins, polycarbonate resins, polyvinyl acetal resins, polyvinyl butyral resins, acrylic resins, silicone resins, epoxy resins, melamine resins, polyurethane resins, phenolic resins, polyvinyl alcohol resins, cellulose resins, polystyrene resins, polyvinyl acetate resins, and polyvinyl chloride resins. Polyvinyl butyral resins are more preferred.

[0034] The charge generating layer may further contain additives such as antioxidants and ultraviolet absorbers, etc. Specific examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds. The average thickness of the charge generating layer is preferably from 0.1 μm to 1 μm, and more preferably from 0.15 μm to 0.4 μm.

[0035] The charge generating layer can be formed by preparing a coating solution for the charge generating layer containing the above-mentioned materials and solvent, forming a coating film from the coating solution, and drying the coating film. Examples of the solvent used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0036] (1-2) Charge transport layer The charge transport layer preferably contains a charge transport material and a binder resin. Examples of the charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these materials. Among these, triarylamine compounds and benzidine compounds are preferred.

[0037] Preferred charge transport materials include compounds represented by formulae (C-1) to (C-12). [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka]

[0038] The content of the charge transport material in the charge transport layer is preferably from 25% by mass to 70% by mass, more preferably from 30% by mass to 55% by mass, based on the total mass of the charge transport layer. Examples of binder resins include polyester resins, polycarbonate resins, acrylic resins, and polystyrene resins. Among these, polycarbonate resins and polyester resins are preferred. As the polyester resin, polyarylate resins are particularly preferred. The content ratio (mass ratio) of the charge transport material to the binder resin is preferably 4:10 to 20:10, and more preferably 5:10 to 12:10.

[0039] The charge transport layer may also contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slipping agents, and abrasion resistance improvers, including hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0040] The average thickness of the charge transport layer is preferably from 5 μm to 50 μm, more preferably from 8 μm to 40 μm, and particularly preferably from 10 μm to 30 μm.

[0041] The charge transport layer can be formed by preparing a coating solution for the charge transport layer containing the above-mentioned materials and solvent, forming a coating film from the coating solution, and drying the coating film. Examples of the solvent used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Among these solvents, ether-based solvents and aromatic hydrocarbon-based solvents are preferred.

[0042] (2) Single-layer photosensitive layer The single-layer photosensitive layer can be formed by preparing a coating solution for the photosensitive layer containing a charge generating material, a charge transport material, a binder resin, and a solvent, forming a coating film from the coating solution, and drying the coating film. The charge generating material, charge transport material, and binder resin are the same as those exemplified in "(1) Multilayer Photosensitive Layer" above.

[0043] <Surface layer> The electrophotographic device of the present invention has a surface layer having a copolymer of a composition containing the compound represented by the above general formula (1) and the compound represented by the above general formula (2). In the present invention, the surface layer is defined as the layer located on the outermost surface of the electrophotographic photoreceptor. In the present invention, the surface layer is a protective layer.

[0044] The surface layer of the present invention contains a compound represented by the above general formula (1) and a compound represented by the above general formula (2). In the electrophotographic device of the present invention, the content of the compound represented by the following general formula (1) in the composition is 10% by mass or more and 50% by mass or less based on the total content of the compound represented by the following general formula (1) and the compound represented by the following general formula (2).

[0045] From the viewpoint of further suppressing image streaks, a more preferred range is that the content of the compound represented by the following general formula (1) in the composition is 10% by mass or more and 40% by mass or less relative to the total content of the compound represented by the following general formula (1) and the compound represented by the following general formula (2).

[0046] From the viewpoint of being able to further suppress image streaks and white spots, a more preferable range is that the content of the compound represented by the following general formula (1) in the composition is from 25% by mass to 40% by mass, based on the total content of the compound represented by the following general formula (1) and the content of the compound represented by the following general formula (2). If the content is in the range of from 25% by mass to 40% by mass, it is thought that slip-through of external additives due to increased surface roughness caused by wear can be suppressed, and the effect of suppressing fusion of external additives can be exerted.

[0047] From the viewpoint of suppressing image streaks and white spots, the compound represented by the general formula (1) is preferably a compound represented by the general formula (1-3), and the compound represented by the general formula (2) is preferably a compound represented by the general formula (2-1).

[0048] In addition, a compound having a polymerizable functional group other than the compounds represented by the general formulas (1) and (2) may be contained. Examples of the polymerizable functional group possessed by the compound having a polymerizable functional group include an acryloyloxy group. Materials without charge transport capability may also be used as the compound having a polymerizable functional group. Examples of reaction methods for forming the surface layer include thermal polymerization, photopolymerization, and radiation polymerization. The surface layer may contain conductive particles and / or a charge transport material and a resin. Examples of conductive particles include titanium oxide particles, zinc oxide particles, tin oxide particles, and indium oxide particles.

[0049] Examples of the charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these materials. Among these, triarylamine compounds and benzidine compounds are preferred.

[0050] Examples of the resin include polyester resin, acrylic resin, phenoxy resin, polycarbonate resin, polystyrene resin, phenol resin, melamine resin, epoxy resin, etc. Among these, polycarbonate resin, polyester resin, and acrylic resin are preferred.

[0051] The surface layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slippage-imparting agents, and abrasion resistance improvers, including hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0052] In the electrophotographic apparatus of the present invention, it is preferable that the composition does not contain fluorine atom-containing resin particles (fluororesin particles) from the viewpoint of suppressing image streaks. In the electrophotographic apparatus of the present invention, it is preferable that the surface layer contains a siloxane-modified acrylic resin as a leveling material, from the viewpoint of suppressing white spots. The average thickness of the surface layer is preferably 0.5 μm or more and 10 μm or less, and more preferably 1 μm or more and 8 μm or less.

[0053] The surface layer can be formed by preparing a coating solution for the protective layer containing the above-mentioned materials and solvent, forming a coating film from this, and drying and / or curing the coating film. Examples of the solvent used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, sulfoxide-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0054] In the electrophotographic apparatus of the present invention, the surface of the surface layer has a maximum height roughness Rmax of 0.30 μm or less as specified in JIS B0601: 1982. When the maximum height roughness Rmax is 0.30 μm or less, image streaks and white spots can be suppressed.

[0055] <About electrophotographic devices> The electrophotographic apparatus of the present invention comprises: an electrophotographic photoreceptor; a charging means for charging the surface of the electrophotographic photosensitive member; an image exposure means for irradiating the surface of the electrophotographic photosensitive member with image exposure light to form an electrostatic latent image on the surface of the electrophotographic photosensitive member; a developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member using a two-component developer having a toner and a magnetic carrier to form a toner image on the surface of the electrophotographic photosensitive member; a cleaning means for cleaning residual toner from the surface of the electrophotographic photosensitive member; a transfer means for transferring the toner image formed on the surface of the electrophotographic photosensitive member onto a recording medium; It has. Each item is explained below.

[0056] [Outline of Electrophotographic Apparatus] An overview of the electrophotographic apparatus and the process cartridge will be described. The electrophotographic apparatus shown in Fig. 1 is an electrophotographic full-color printer having four image forming units (first, second, third, and fourth image forming units) 1Y, 1M, 1C, and 1Bk, which are provided corresponding to the four colors of yellow, magenta, cyan, and black.

[0057] The electrophotographic apparatus can form a four-color full-color image on a recording material P (recording paper, plastic film, cloth, etc.) in response to image signals from the following devices connected to the main body of the electrophotographic apparatus: a document reading device (not shown), a host device such as a personal computer, or an external device such as a digital camera.

[0058] The electrophotographic device includes cylindrical electrophotographic photosensitive members 2Y, 2M, 2C, and 2Bk as image carriers in first to fourth image forming units 1Y, 1M, 1C, and 1Bk. The toner images formed on these electrophotographic photosensitive members are transferred onto an intermediate transfer belt 8 as an intermediate transfer member. The toner images on the intermediate transfer belt 8 are then transferred onto a recording material P, thereby forming a recorded image.

[0059] The electrophotographic apparatus may be a monochromatic apparatus having only one image forming unit, an apparatus having image forming units of four or more colors, or an apparatus having a single image forming unit and developing units of multiple colors.

[0060] Any plurality of components of the image forming unit may be integrated into a unit to form a process cartridge, which can be detachably mounted on an electrophotographic apparatus such as a copying machine or a laser beam printer.

[0061] [Configuration and Operation of Electrophotographic Apparatus] Next, the configuration and operation of the electrophotographic apparatus will be described in more detail. In the following description, elements common to the four image forming units 1Y, 1M, 1C, and 1Bk will be given the same reference numerals with the suffixes Y, M, C, and Bk added. When there is no need to distinguish between them, the suffixes Y, M, C, and Bk added to the reference numerals to indicate that the element is provided for one of the colors will be omitted, and the element will be described in general terms.

[0062] In the image forming unit 1, a cylindrical electrophotographic photosensitive member 2 is disposed as an image carrier. The electrophotographic photosensitive member 2 is driven to rotate in the direction of the arrow in the figure. Around the electrophotographic photosensitive member 2, a charging roller 3 as a charging means, a developing device 4 as a developing means, a primary transfer roller 5 as a primary transfer means, and a cleaning device 6 as a cleaning means are disposed. Also, an image exposure device 7 as an image exposure means is disposed above the electrophotographic photosensitive member 2 in the figure. Also, an intermediate transfer belt 8 as an intermediate transfer member is disposed facing the electrophotographic photosensitive member 2 of each image forming unit 1. The intermediate transfer belt 8 is wound around a drive roller 9, a secondary transfer opposing roller 10, and a driven roller 11, and moves in the direction of the arrow in the figure by the driving force transmitted to the drive roller 9. At the position where the primary transfer roller 5 and the electrophotographic photosensitive member 2 face each other, the intermediate transfer belt 8 comes into contact with the electrophotographic photosensitive member 2, forming a primary transfer portion (primary transfer nip). Further, a secondary transfer roller 12 as a secondary transfer means is provided at a position facing the secondary transfer opposing roller 10 across the intermediate transfer belt 8. The secondary transfer roller 12 comes into contact with the intermediate transfer belt 8 at a position facing the secondary transfer opposing roller 10, forming a secondary transfer portion (secondary transfer nip).

[0063] The electrophotographic apparatus can be equipped with a full-color image forming mode using all of the first to fourth image forming stations 1Y, 1M, 1C, and 1Bk, and a black monochrome image forming mode using only the fourth image forming station 1Bk. First, the image forming operation in the full-color image forming mode will be described.

[0064] <Electrified> When the image forming operation starts, the surfaces of the rotating electrophotographic photosensitive members 2Y, 2M, 2C, and 2Bk in the image forming units 1Y, 1M, 1C, and 1Bk are uniformly charged by the charging rollers 3Y, 3M, 3C, and 3Bk. At this time, a charging bias is applied to the charging rollers 3Y, 3M, 3C, and 3Bk from a charging bias power supply. The charging means may be a corona charger.

[0065] Image exposure Next, image exposure devices 7Y, 7M, 7C, and 7Bk emit image exposures in accordance with image signals for the separation colors corresponding to the respective image forming units, whereby each of the electrophotographic photosensitive members 2Y, 2M, 2C, and 2Bk is exposed in accordance with image information for the corresponding separation colors, and an electrostatic image (electrostatic latent image) is formed thereon in accordance with the image signal.

[0066] <developing> The electrostatic images formed on the electrophotographic photosensitive members 2Y, 2M, 2C, and 2Bk are developed into toner images using toner contained in the respective developing units 4Y, 4M, 4C, and 4Bk. For example, when a reversal development method is adopted, toner from the developing unit 4 adheres to the exposed areas (bright potential areas) on the electrophotographic photosensitive member 2.

[0067] <Primary Transcription> The toner images formed on the electrophotographic photosensitive members 2Y, 2M, 2C, and 2Bk are transferred (primary transfer) sequentially onto the intermediate transfer belt 8 at each primary transfer portion (primary transfer nip) so as to be superimposed on the intermediate transfer belt 8. At this time, a primary transfer bias having a polarity opposite to the normal charging polarity of the toner is applied to the primary transfer rollers 5Y, 5M, 5C, and 5Bk from a primary transfer bias power supply. In this way, a multiple toner image in which four color toner images are superimposed is formed on the intermediate transfer belt 8.

[0068] <cleaning> Toner remaining on the surfaces of the electrophotographic photosensitive members 2Y, 2M, 2C, and 2Bk after the primary transfer (primary transfer residual toner) is collected by cleaning devices 6Y, 6M, 6C, and 6Bk. Separately, a charge removal process may be performed using pre-exposure light from a pre-exposure means (not shown) to perform electrical cleaning.

[0069] <Secondary transfer> Meanwhile, in synchronization with the movement of the toner image on the intermediate transfer belt 8, a recording material P stored in a recording material storage cassette (not shown) is transported to a secondary transfer portion (secondary transfer nip) by a supply roller 13 or the like. Then, the multiple toner images on the intermediate transfer belt 8 are transferred (secondary transfer) all at once onto the recording material P at the secondary transfer portion (secondary transfer nip). At this time, a secondary transfer bias having a polarity opposite to the normal charging polarity of the toner is applied to the secondary transfer roller 12 from a secondary transfer bias power supply. Note that toner that is not transferred to the recording material P at the secondary transfer portion (secondary transfer nip) and remains on the intermediate transfer belt 8 (secondary transfer residual toner) is collected by an intermediate transfer belt cleaner 15.

[0070] <Establishment> The recording material P onto which the toner image has been transferred is transported by a transport member or the like to a fixing device 14 serving as a fixing means. By applying heat and pressure in the fixing device 14, the toner on the recording material P is melted, mixed, and fixed to the recording material P, becoming a permanent full-color image. Thereafter, the recording material P is discharged outside the machine.

[0071] Next, the image forming operation in the monochrome image forming mode will be described. In the monochrome image forming mode, a toner image is formed on the electrophotographic photosensitive member 2Bk only in the fourth image forming station 1Bk. This toner image is then primarily transferred to the intermediate transfer belt 8, and then secondarily transferred to the recording material P. The toner image forming operation, primary transfer operation, and secondary transfer operation in the fourth image forming station 1Bk are the same as those in the full-color image forming mode described above.

[0072] [Charging means] Either non-contact or contact charging methods can be used as the charging method. Corona charging, a non-contact charging method, has a relatively high output and is suitable for high-speed processes. Contact charging methods are widely used because they have excellent charging uniformity and are small in size.

[0073] The contact charging method uses a charging roller as a charging member, which is made by providing a conductive elastic layer on the outer periphery of a conductive support (metal core) and coating the outer periphery of the conductive elastic layer with a resistive layer. This charging roller is then rotatably arranged in contact with an electrophotographic photosensitive member, and a voltage is applied to the metal core, causing a minute discharge near the contact nip between the charging roller and the electrophotographic photosensitive member, thereby charging the surface of the electrophotographic photosensitive member. Here, the charging member does not necessarily need to be in contact with the electrophotographic photosensitive member; as long as a dischargeable region determined by the gap voltage and the corrected Paschen curve is secured between the charging member and the electrophotographic photosensitive member, it may be arranged in close proximity without contact, for example, with a gap of several tens of micrometers. Although this proximity charging is non-contact, it is functionally classified as contact charging.

[0074] There are two types of contact charging methods: DC charging, in which only DC voltage is applied to the core, and AC+DC charging, in which AC voltage is superimposed on DC voltage to create an oscillating voltage. In the AC / DC charging method, an oscillating voltage is applied to the charging member, which is a superposition of a direct current (DC) voltage equivalent to the desired charging potential VD of the photoconductor and an AC voltage with a peak-to-peak voltage at least twice the discharge threshold Vth when the DC voltage is applied. The AC / DC charging method has the advantage that the potential leveling effect of the AC voltage makes it easy to converge the potential of the photoconductor to the DC voltage and obtain the desired charging potential VD. On the other hand, the DC charging method does not require an AC power source, which has the advantage of allowing for smaller and less expensive devices.

[0075] In the AC+DC charging method, uniform charging can be achieved by alternately discharging the positive and negative sides using an oscillating voltage. To achieve uniform charging, it is preferable to apply a superimposed AC voltage with a peak-to-peak voltage (Vpp) at least twice the charging initiation voltage when a DC voltage is applied. The waveform of the oscillating voltage is not limited to a sine wave, but can also be a square wave, triangular wave, or pulse wave. Examples of oscillating voltages include a square wave voltage formed by periodically turning a DC voltage on and off, and a DC voltage whose value is periodically changed to achieve the same output as a superimposed voltage of an AC voltage and a DC voltage. The applied voltage can be selected as needed, but a range of -1000 V to -400 V is preferred. To ensure consistent discharge, the AC voltage is preferably at least twice that of the DC voltage. A peak-to-peak voltage (Vpp) of 1000 V to 3000 V and a frequency of 0.5 kHz to 3 kHz are preferred.

[0076] The charging device uses a roller (hereinafter also referred to as a charging roller) that rotates in contact with the electrophotographic photosensitive member. The charging roller is arranged in contact with the electrophotographic photosensitive member and forms a charging nip, which is the contact point with the electrophotographic photosensitive member. The charging roller uses a conductive core metal that forms the shaft as a base, and an elastic layer is provided on top of this. The conductive core metal can be made of metal materials such as iron, copper, stainless steel, and aluminum. The conductive core may be plated to provide rust prevention and scratch resistance, as long as the conductive core does not lose its conductivity.

[0077] Considering deflection when pressure is applied to the electrophotographic photosensitive member, the elastic layer preferably has a so-called crown shape, with the center portion in the longitudinal direction (the direction of the rotation axis of the electrophotographic photosensitive member) being thicker and the both ends in the longitudinal direction being thinner. This is because the charging roller is designed so that both ends in the longitudinal direction receive a predetermined pressure toward the electrophotographic photosensitive member from a pressure mechanism. This is to suppress the tendency for the contact pressure of the charging roller against the electrophotographic photosensitive member at the longitudinal center portion to be smaller than at the ends. When the longitudinal length of the elastic body is 220 mm or more and 340 mm or less, the crown amount is preferably 0.01 mm or more and 0.300 mm or less. Figure 3 is a schematic diagram showing the crown shape of the charging roller. The crown amount represents the value obtained by subtracting the diameter d2 of the end portion from the diameter d1 of the elastic layer 302 at the center of the charging roller in Figure 3. 301 represents a conductive core.

[0078] The material for forming the elastic layer may contain a binder resin and conductive particles. Examples of binder resins include: natural rubber, butadiene rubber, styrene butadiene rubber (SBR), nitrile rubber, ethylene propylene rubber (EPDM), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), epichlorohydrin rubber, butyl rubber, silicone rubber, urethane rubber, fluororubber, and chlorine rubber, as well as thermoplastic elastomers. Among these, NBR is preferred from the viewpoint of compression set and hardness. The charging roller may use, for example, a conductive core metal with a diameter of "8 mm," and a conductive agent may be added to the elastic layer to achieve a volume resistivity of "1 x 10 10 The resistivity is adjusted to be equal to or less than Ωcm. A protective layer may be provided on the surface of the elastic layer to prevent leakage. Examples of materials for the protective layer include acrylic resin and urethane resin. The protective layer preferably has a thickness of about 3 to 15 μm. The charging roller is pressed against the electrophotographic photosensitive member at a predetermined contact pressure. The charging roller rotates in accordance with the rotation of the electrophotographic photosensitive member.

[0079] [Image Exposure Means] Image exposure is performed by converting information read by a document reader or electronic data generated by an information device such as a personal computer into a signal, and then irradiating the image from the image exposure device in accordance with this signal. The image exposure means can be a laser beam scanning light, or light irradiated by driving an LED array or liquid crystal shutter array.

[0080] As an example of an image exposure device, the structure of a solid-state exposure head will be described. A solid-state exposure head has multiple light-emitting points, such as LEDs or organic ELs, arranged in a roughly linear fashion in a direction parallel to the rotation axis of the electrophotographic photosensitive member (main scanning direction), and exposes the electrophotographic photosensitive member all at once in the main scanning direction.

[0081] FIG. 2 shows a cross-sectional view of a solid-state exposure head 201 as an example. A light-emitting substrate 202 on which multiple LED chips are mounted and aligned in the main scanning direction (the direction of the rotation axis of the photosensitive member), and a lens array 206 on which multiple cylindrical gradient index lenses are aligned in the same main scanning direction, are held in a housing 205. The housing 205 is made of a zinc-plated steel plate or a cold-rolled steel plate that has been plated afterwards. The lens array 206 focuses the light beams emitted from the LED light-emitting points 203 onto the electrophotographic photosensitive member 103 as an erect image at 1:1 magnification. At this time, the distance from the LED light-emitting points to the entrance surface of the lens array 206 and the distance from the exit surface of the lens array 206 to the surface of the electrophotographic photosensitive member 103 are approximately equal.

[0082] The distance between the LED light emitting point 203 and the incident surface of the lens array 206 must be highly accurate on the order of μm, and after this distance is precisely adjusted, the light emitting substrate 202 and lens array 206 are fixed by adhesive to the housing 205. In this embodiment, an LED is used as the solid-state exposure light source, and the light emitting substrate 202, lens array 206, and housing 205 integrated into one unit is called the solid-state exposure head 201.

[0083] [Developing means] The developing unit mainly comprises a developing container, a developer stirring and transporting member, a developer carrier, and a developer layer thickness regulating member. An example is shown below.

[0084] This will be explained with reference to FIG. FIG. 4 is a longitudinal cross-sectional view of the developing unit 4 and the toner supply device 49. As shown in FIG. The developing unit 4 has a developing container 44 that stores developer. The interior of the developing container 44 is divided into a developing chamber 44a and an agitating chamber 44b by a partition wall 44d. The developing chamber 44a and the agitating chamber 44b are connected at both longitudinal ends of the developing container 44. A first agitating / conveying screw 43a is provided in the developing chamber 44a, and a second agitating / conveying screw 43b is provided in the agitating chamber 44b. The first and second agitating / conveying screws 43a and 43b are driven by a motor 52 to rotate in the same direction via a gear train 54. This rotation transports the developer in the direction of the arrow in FIG. 4, circulating between the agitating chamber 44b and the developing chamber 44a. At this time, an electric charge is imparted to the developer.

[0085] The developing chamber 44a is in contact with the developer carrier 41. The developer carrier 41 contains a magnet roll with multiple magnetic poles in the circumferential direction. This magnetic force draws up the developer in the developing chamber 44a and forms the developer spikes (magnetic brushes).

[0086] The outer surface of the developer carrier 41 is made of a non-magnetic material such as aluminum or stainless steel. The outer surface of the developer carrier 41 may be textured to facilitate developer transport. Examples include a sandblasted uneven surface or multiple V-shaped grooves. V-shaped grooves are preferred from the perspective of maintaining the shape. The V-shaped grooves are preferably parallel to the longitudinal direction of the sleeve, have 40 to 120 grooves in the circumferential direction (at a diameter of 20 mm), have a slope angle of 60° to 120°, and have a groove depth of 20 μm to 100 μm. The developer carrier 41 is driven to rotate by a motor 51. The rotation direction may be with or counter to the rotation direction of the electrophotographic photosensitive member. If the rotation direction is with the electrophotographic photosensitive member, the rotation speed is preferably more than 1 to 2.5 times the rotation speed of the electrophotographic photosensitive member to provide a difference in peripheral speed.

[0087] The developer carrier 41 transports the developer to the development position facing the electrophotographic photosensitive member 2. At the development position, a developer layer thickness regulating member is provided to form appropriate developer spikes (magnetic brushes). First, at the development position, a developer reservoir is formed by the cutting pole of the magnet roll, and the thickness of this reservoir is regulated by the layer thickness regulating member. The layer thickness regulating member can be a magnetic plate blade, a non-magnetic plate blade, a combination of both, or an elastic blade.

[0088] The magnetic brush is brought into contact with the photosensitive member, and the toner in the developer adheres to the electrostatic image on the photosensitive member, developing the electrostatic image into a toner image. During development, a development voltage is applied to the developer carrier 41 from a power source (not shown). By applying a DC voltage appropriate to the potential of the electrostatic image, the electrostatic image can be developed faithfully. An AC voltage may be superimposed on the development voltage, and a square wave or a square wave with a pause can be selected. The AC voltage preferably has a frequency of 5 kHz to 20 kHz and an amplitude of 0.5 kV to 2 kV.

[0089] The toner supply device 49 will now be described. The toner supply device 49 has a toner container (toner supply tank, toner storage unit) 46 that stores toner to be supplied to the developing device 4. A toner discharge port 48 is provided at the bottom of the toner container 46 and is connected to the toner supply port 44c of the developing device 4. The toner container 46 also has a toner supply screw 47 that transports toner. The toner supply screw 47 is rotated by a motor 53. The amount of toner supplied can be changed by changing the rotation time and rotation speed of the motor 53. The rotation of the motor 53 is controlled by a CPU (control means) 61 of an engine control unit 60 provided in the electrophotographic apparatus. The CPU 61 controls motor rotation to supply toner based on information on toner consumption and remaining toner amount and the relationship between motor rotation and toner supply amount (in ROM 62 or CPU 61). In FIG. 4, 42 denotes a toner concentration detection means, and 45 denotes a toner remaining amount detection means, which obtain information on toner consumption and remaining toner amount.

[0090] The toner in the toner supply device 49 may be toner containing a small amount of carrier in order to recover from carrier deterioration in the developer in the developing device 4. In this case, since the amount of developer in the developing device 4 increases as the developer is replenished, an outlet may be provided in the stirring chamber 44b. To optimize the amount of developer discharged, the screw shape near the outlet of the stirring and conveying screw 43b may be changed, or a magnet member may be installed near the outlet.

[0091] [Developer] In the present invention, a two-component developer is used as the developer. For example, a magnetic two-component developer is prepared by mixing a magnetic carrier and a toner (described later) in a V-type mixer (V-10 type: Tokuju Manufacturing Co., Ltd.) for 0.5 seconds to obtain a toner concentration of 8.0% by mass. -1 The mixture can be obtained by mixing with a rotation time of 5 minutes.

[0092] <Developer Toner> The toner contains colored resin particles containing binder resin, wax, colorant, and optionally other additives, and colored particles to which an external additive such as colloidal silica fine powder has been added. The volume average particle size is preferably 4 μm or more and 8 μm or less. The average circularity of the toner is preferably 0.930 or more and 0.985 or less. To further improve transfer efficiency, it is preferably 0.960 or more, and more preferably 0.965 or more.

[0093] -Binder resin- Examples of binder resins used in toners include homopolymers of styrene and its substituted derivatives, such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers, styrene-acrylic acid ester copolymers, styrene-methacrylic acid ester copolymers, styrene-α-chloromethyl methacrylate copolymers, styrene-acrylonitrile copolymers, styrene-vinyl methyl ether copolymers, styrene-vinyl ethyl ether copolymers, styrene-vinyl methyl ketone copolymers, and styrene-acrylonitrile-indene copolymers; and polyvinyl chloride, phenolic resins, naturally modified phenolic resins, naturally resin-modified maleic acid resins, acrylic resins, methacrylic resins, polyvinyl acetate, silicone resins, polyester resins, polyurethanes, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resins, coumarone-indene resins, and petroleum-based resins.

[0094] Among these, polyester resins are preferred from the viewpoints of low-temperature fixability and charge control. Monomers used in the polyester unit include polyhydric alcohols (dihydric, trihydric or higher alcohols), polycarboxylic acids (dihydric, trihydric or higher carboxylic acids), acid anhydrides thereof, or lower alkyl esters thereof.

[0095] Examples of dihydric alcohols include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, bisphenol, and derivatives thereof.

[0096] Examples of trihydric or higher alcohol components include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxymethylbenzene. Of these, glycerol and trimethylolpropane are preferred. These dihydric alcohols and trihydric or higher alcohols can be used alone or in combination.

[0097] Examples of dicarboxylic acid components include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, n-dodecenylsuccinic acid, isododecenylsuccinic acid, n-dodecylsuccinic acid, isododecylsuccinic acid, n-octenylsuccinic acid, n-octylsuccinic acid, isooctenylsuccinic acid, isooctylsuccinic acid, anhydrides of these acids, and lower alkyl esters thereof. Among these, particularly preferred are maleic acid, fumaric acid, terephthalic acid, and n-dodecenylsuccinic acid.

[0098] Examples of trivalent or higher carboxylic acids, their acid anhydrides, or their lower alkyl esters include 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxy-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra(methylenecarboxy)methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, empol trimer acid, and their acid anhydrides or lower alkyl esters. Among these, 1,2,4-benzenetricarboxylic acid, i.e., trimellitic acid or its derivatives, is particularly preferred due to its low cost and easy reaction control. These divalent carboxylic acids and trivalent or higher carboxylic acids can be used alone or in combination.

[0099] The hybrid resin may be a hybrid resin containing a polyester resin as a main component, or a hybrid resin of a polyester resin and a vinyl resin. A preferred method for obtaining the hybrid resin is to carry out a polymerization reaction of one or both of the resins in the presence of a polymer containing a monomer component capable of reacting with the vinyl resin, the vinyl copolymer unit, and the polyester resin.

[0100] Among the monomers constituting the polyester resin component, those capable of reacting with the vinyl copolymer include, for example, unsaturated dicarboxylic acids such as phthalic acid, maleic acid, citraconic acid, and itaconic acid, or anhydrides thereof, etc. Among the monomers constituting the vinyl copolymer component, those capable of reacting with the polyester resin component include those having a carboxy group or a hydroxy group, and acrylic acid or methacrylic acid esters.

[0101] In addition to the polyester resin as the main component, various resin compounds can be used in combination, such as phenolic resin, natural resin-modified phenolic resin, natural resin-modified maleic resin, acrylic resin, methacrylic resin, polyvinyl acetate resin, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumaroindene resin, and petroleum-based resin.

[0102] The binder resin may be a mixture of a low molecular weight binder resin L and a high molecular weight binder resin H. The content ratio (H / L) of the high molecular weight binder resin H to the low molecular weight binder resin L is preferably 10 / 90 or more and 60 / 40 or less by mass, from the viewpoint of low temperature fixability and hot offset resistance. The peak molecular weight of the high molecular weight binder resin A is preferably 10,000 or more and 20,000 or less, from the viewpoint of hot offset resistance. Furthermore, the acid value of the high molecular weight binder resin is preferably 2 mgKOH / g or more and 20 mgKOH / g or less, from the viewpoint of charge stability in a high temperature and high humidity environment. The number average molecular weight of the low molecular weight binder resin B is preferably 3,000 or more and 7,000 or less, from the viewpoint of low temperature fixability. Furthermore, the acid value of the low molecular weight binder resin is preferably 10 mgKOH / g or less, from the viewpoint of charge stability in a high temperature and high humidity environment.

[0103] -Crystalline resin- The toner preferably contains a crystalline resin for low-temperature fixability. It is important that the crystalline resin is a crystalline ester compound or a crystalline ether compound. By using a crystalline ester compound or a crystalline ether compound, the polyester resin of the binder resin can be plasticized to improve low-temperature fixability. In order to fully exert the plasticizing effect, it is preferable to use a polyester as the crystalline resin.

[0104] The crystalline polyester contained in the toner particles is obtained by polycondensation of a monomer composition containing an aliphatic diol and an aliphatic dicarboxylic acid as main components. The aliphatic diol and the aliphatic dicarboxylic acid preferably have 6 to 12 carbon atoms.

[0105] The aliphatic diol is preferably a chain (more preferably a straight-chain) aliphatic diol, such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,4-butadiene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, nonamethylene glycol, decamethylene glycol, and neopentyl glycol. Among these, particularly preferred are straight-chain aliphatic diols such as ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol, as well as α,ω-diols. Of the alcohol components, preferably 50% by mass or more, more preferably 70% by mass or more, is an alcohol selected from aliphatic diols having 6 to 12 carbon atoms.

[0106] Polyhydric alcohol monomers other than the above-mentioned aliphatic diols can also be used. Among these polyhydric alcohol monomers, dihydric alcohol monomers include aromatic alcohols such as polyoxyethylenated bisphenol A and polyoxypropylenated bisphenol A; and 1,4-cyclohexanedimethanol. Furthermore, among these polyhydric alcohol monomers, trihydric or higher polyhydric alcohol monomers include aromatic alcohols such as 1,3,5-trihydroxymethylbenzene; and aliphatic alcohols such as pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, and trimethylolpropane.

[0107] Furthermore, monohydric alcohols may be used to the extent that they do not impair the properties of the crystalline polyester, such as monofunctional alcohols such as n-butanol, isobutanol, sec-butanol, n-hexanol, n-octanol, lauryl alcohol, 2-ethylhexanol, decanol, cyclohexanol, benzyl alcohol, and dodecyl alcohol.

[0108] On the other hand, the aliphatic dicarboxylic acid is preferably a chain (more preferably a linear) aliphatic dicarboxylic acid. Examples include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, glutaconic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, and itaconic acid, as well as their acid anhydrides or hydrolyzed lower alkyl esters. Of the carboxylic acid components, preferably 50% by mass or more, more preferably 70% by mass or more, is a carboxylic acid selected from aliphatic dicarboxylic acids having 6 to 12 carbon atoms.

[0109] Polycarboxylic acids other than aliphatic dicarboxylic acids can also be used. Among the other polycarboxylic acid monomers, dicarboxylic acids include aromatic carboxylic acids such as isophthalic acid and terephthalic acid; aliphatic carboxylic acids such as n-dodecylsuccinic acid and n-dodecenylsuccinic acid; and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid, as well as their acid anhydrides and lower alkyl esters. Among the other carboxylic acid monomers, tricarboxylic or higher polycarboxylic acids include aromatic carboxylic acids such as 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and pyromellitic acid; and aliphatic carboxylic acids such as 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, and 1,3-dicarboxy-2-methyl-2-methylenecarboxypropane, as well as their acid anhydrides and lower alkyl esters.

[0110] The crystalline polyester may contain a monocarboxylic acid to the extent that the properties of the crystalline polyester are not impaired. Examples of the monocarboxylic acid include benzoic acid, naphthalenecarboxylic acid, salicylic acid, 4-methylbenzoic acid, 3-methylbenzoic acid, phenoxyacetic acid, biphenylcarboxylic acid, acetic acid, propionic acid, butyric acid, octanoic acid, decanoic acid, dodecanoic acid, and stearic acid.

[0111] Crystalline polyesters can be produced according to conventional polyester synthesis methods. For example, the desired crystalline polyester can be obtained by esterifying or transesterifying the carboxylic acid monomer and alcohol monomer described above, followed by polycondensation under reduced pressure or by introducing nitrogen gas, according to a conventional method. The esterification or transesterification reaction can be carried out using a conventional esterification or transesterification catalyst, such as sulfuric acid, titanium butoxide, dibutyltin oxide, manganese acetate, or magnesium acetate, as needed. The polycondensation reaction can be carried out using a conventional polymerization catalyst, or a known catalyst, such as titanium butoxide, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, or germanium dioxide. The polymerization temperature and catalyst amount are not particularly limited.

[0112] In the esterification or transesterification reaction or polycondensation reaction, all the monomers may be charged at once to increase the strength of the resulting crystalline polyester. Alternatively, to reduce the amount of low-molecular-weight components, a divalent monomer may be reacted first, and then a trivalent or higher monomer may be added and reacted.

[0113] The crystalline polyester is preferably contained in an amount of 1.0 to 15 parts by weight per 100 parts by weight of the amorphous resin. If the amount of crystalline resin is too small, the plasticizing effect is insufficient, and low-temperature fixability is not improved. If too much crystalline resin is added, the toner tends to absorb moisture, which impairs color stability. From the viewpoint of suppressing moisture adsorption, the acid value is preferably 2 mgKOH / g or more and 20 mgKOH / g or less.

[0114] -wax- Examples of waxes used in toner include the following: Examples of such waxes include hydrocarbon waxes such as low-molecular-weight polyethylene, low-molecular-weight polypropylene, alkylene copolymers, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax; oxides of hydrocarbon waxes such as oxidized polyethylene wax or block copolymers thereof; waxes containing fatty acid esters as the main component such as carnauba wax; and partially or completely deoxidized fatty acid esters such as deoxidized carnauba wax. Saturated straight-chain fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassidic acid, eleostearic acid, and valinaric acid; saturated alcohols such as stearyl alcohol, aralkyl alcohols, behenyl alcohol, carnaubyl alcohol, ceryl alcohol, and melissyl alcohol; polyhydric alcohols such as sorbitol; esters of fatty acids such as palmitic acid, stearic acid, behenic acid, and montanic acid with alcohols such as stearyl alcohol, aralkyl alcohols, behenyl alcohol, carnaubyl alcohol, ceryl alcohol, and melissyl alcohol; fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide; methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, and hexamethylenebisstearate amide. Saturated fatty acid bisamides such as stearic acid amide; unsaturated fatty acid amides such as ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipamide, and N,N'-dioleyl sebacic acid amide; aromatic bisamides such as m-xylene bisstearic acid amide and N,N'-distearyl isophthalic acid amide; fatty metal salts (commonly known as metal soaps) such as calcium stearate, calcium laurate, zinc stearate, and magnesium stearate; waxes grafted onto aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid; partial esters of fatty acids and polyhydric alcohols such as behenic acid monoglyceride; and methyl ester compounds with hydroxy groups obtained by hydrogenating vegetable oils and fats. Among these waxes, hydrocarbon waxes such as paraffin wax and Fischer-Tropsch wax are preferred from the viewpoint of improving low-temperature fixability and anti-wrapping properties after fixation.

[0115] The content of the wax is preferably 0.5 parts by mass or more and 20 parts by mass or less relative to 100 parts by mass of the binder resin. From the viewpoint of achieving both the storage stability and high-temperature offset resistance of the toner, it is preferable that the peak temperature of the maximum endothermic peak present in the temperature range of 30°C to 200°C in an endothermic curve during temperature rise measured with a differential scanning calorimeter (DSC) is 50°C to 110°C.

[0116] -Wax dispersant- The toner preferably contains a wax dispersant in order to improve blocking resistance and hot offset resistance. A polymer in which a styrene-acrylic polymer is graft-modified onto a polyolefin is preferred. The styrene-acrylic polymer is preferably one having a unit derived from a cycloalkyl(meth)acrylate.

[0117] Examples of polyolefins include low-molecular-weight polyethylene, low-molecular-weight polypropylene, alkylene copolymers, microcrystalline wax, paraffin wax, and hydrocarbon waxes such as Fischer-Tropsch wax. Furthermore, the peak temperature of the maximum endothermic peak measured using a differential scanning calorimeter (DSC) is preferably 70°C or higher and 90°C or lower. The styrene-acrylic polymer may be a homopolymer of a vinyl monomer or a copolymer with other monomers.

[0118] The cycloalkyl (meth)acrylate-derived unit is preferably a saturated alicyclic hydrocarbon group, such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a t-butylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, a tricyclodecanyl group, a decahydro-2-naphthyl group, a tricyclo[5.2.1.02,6]decan-8-yl group, a pentacyclopentadecanyl group, an isobornyl group, an adamantyl group, a dicyclopentanyl group, or a tricyclopentanyl group. The unit may have a substituent such as an alkyl group, a halogen atom, a carboxy group, a carbonyl group, or a hydroxy group.

[0119] The wax dispersant preferably has a weight-average molecular weight (Mw) of 5,000 to 70,000 inclusive, as determined by GPC molecular weight distribution of styrene-acrylic resin. When the weight-average molecular weight (Mw) is 5,000 or more, the wax dispersant remains in the toner, suppressing elution of wax onto the toner surface when left at high temperature and humidity, improving the toner's blocking resistance. Furthermore, when the weight-average molecular weight (Mw) is 70,000 or less, the wax finely dispersed in the toner can quickly migrate to the molten toner surface during fixing and melting, improving release properties during fixing and reducing the likelihood of high-temperature offset.

[0120] -Coloring agent- Examples of colorants used in toner include the following: Examples of black colorants include carbon black and those toned to black using a yellow colorant, a magenta colorant, and a cyan colorant. As the colorant, a pigment may be used alone, but it is more preferable to use a dye and a pigment in combination to improve the clarity from the viewpoint of the image quality of a full-color image.

[0121] Examples of magenta coloring pigments include the following: CI Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48:2, 48:3, 48:4, 49, 50, 51, 52, 53, 54, 55, 57:1, 58, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 3, 64, 68, 81:1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 146, 147, 150, 163, 184, 202, 206, 207, 209, 238, 269, 282; CI Pigment Violet 19; CI Vat Red 1, 2, 10, 13, 15, 23, 29, 35. Magenta-colored dyes include the following: Examples of suitable dyes include solvent dyes such as CI Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, and 121; CI Disperse Red 9; CI Solvent Violet 8, 13, 14, 21, and 27; and CI Disperse Violet 1; and basic dyes such as CI Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, and 40; and CI Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, and 28.

[0122] Examples of cyan pigments include CI Pigment Blue 2, 3, 15:2, 15:3, 15:4, 16, and 17; CI Vat Blue 6; CI Acid Blue 45; and copper phthalocyanine pigments having one to five phthalimidomethyl groups substituted on the phthalocyanine skeleton. Examples of cyan dyes include CI Solvent Blue 70.

[0123] Yellow coloring pigments include, for example, CI Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 62, 65, 73, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, and 185; CI Vat Yellow 1, 3, and 20; and yellow coloring dyes include, for example, CI Solvent Yellow 162. The amount of the colorant used is preferably 0.1 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0124] -Charge control agent- The toner may contain a charge control agent as needed. Known charge control agents can be used as the charge control agent contained in the toner, but metal compounds of aromatic carboxylic acids are particularly preferred because they are colorless, can charge the toner quickly, and can stably maintain a constant charge amount.

[0125] Examples of negative charge control agents include metal salicylate compounds, metal naphthoate compounds, metal dicarboxylate compounds, polymeric compounds having sulfonic acid or carboxylic acid on the side chain, polymeric compounds having sulfonate salts or sulfonate esters on the side chain, polymeric compounds having carboxylate salts or carboxylate esters on the side chain, boron compounds, urea compounds, silicon compounds, calixarene, etc. The charge control agent may be added internally or externally to the toner particles. The amount of the charge control agent added is preferably 0.2 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0126] -Inorganic fine particles- The toner may contain inorganic fine particles as needed. The inorganic fine particles may be added internally to the toner particles or may be mixed with the toner particles as an external additive. As the inorganic fine particles, inorganic fine powders such as silica, titanium oxide, strontium titanate, and aluminum oxide are preferred. The inorganic fine powders are preferably hydrophobicized with a silane compound, silicone oil, or a mixture thereof.

[0127] As inorganic fine particles for improving fluidity, a specific surface area of ​​50m 2 / g or more 400m 2 / g or less of inorganic fine powder is preferred, and for stable durability, a specific surface area of ​​10 m 2 / g or more 50m 2 In order to simultaneously improve the flowability and stabilize the durability, inorganic fine powders having a specific surface area within the above range may be used in combination.

[0128] The inorganic fine particles are preferably used in an amount of 0.1 parts by mass to 10.0 parts by mass relative to 100 parts by mass of toner particles. The toner particles and the inorganic fine particles can be mixed using a known mixer such as a Henschel mixer.

[0129] -Manufacturing method- Known manufacturing methods can be used. In particular, the melt-kneading step improves the dispersibility of the wax and the blocking resistance. Furthermore, the use of the bulky hydrophobic wax dispersant can prevent the wax from being exposed on the surface even after the heat treatment step, thereby preventing a decrease in the chargeability and blocking resistance.

[0130] ·Raw material mixing process The raw materials of the toner, such as binder resin, crystalline resin, wax, wax dispersant, colorant, and charge control agent, are weighed and mixed. As a mixing device, a Henschel mixer (manufactured by Nippon Coke Company), a Supermixer (manufactured by Kawata Corporation), a Ribocone (manufactured by Okawara Manufacturing Co., Ltd.), a Nauta mixer, a Turbulizer, or a Cyclomix (manufactured by Hosokawa Micron Corporation), a Spiral Pin Mixer (manufactured by Pacific Machinery Works, Ltd.), or a Loedige mixer (manufactured by Matsubo Corporation) can be used.

[0131] Melt-mixing process The mixed raw materials are melt-kneaded to disperse the colorant, wax, etc. in the binder resin. In this melt-kneading process, a batch kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used. Examples include a TEM-type extruder (manufactured by Toshiba Machine Co., Ltd.), a TEX twin-screw kneader (manufactured by The Japan Steel Works, Ltd.), a PCM kneader (manufactured by Ikegai Iron Works, Ltd.), a Kneadex (manufactured by Mitsui Mining Co., Ltd.), a KTK-type twin-screw extruder (manufactured by Kobe Steel, Ltd.), a twin-screw extruder (manufactured by KCK Corporation), and a Co-Kneader (manufactured by Buss Co., Ltd.). The colored resin composition obtained by melt-kneading the toner raw materials is melt-kneaded, rolled using a twin roll, etc., and cooled using water cooling or the like.

[0132] Crushing process The cooled colored resin composition is pulverized to a desired particle size. In the pulverization step, the pulverized material is coarsely pulverized using a pulverizer such as a crusher, hammer mill, or feather mill, and then further pulverized using a pulverizer such as a Cryptron System (manufactured by Kawasaki Heavy Industries, Ltd.), a Super Rotor (manufactured by Nisshin Engineering Co., Ltd.), a Turbo Mill (manufactured by Turbo Kogyo Co., Ltd.), or an air jet type pulverizer, to obtain toner particles.

[0133] ·Classification process The toner particles are classified into powder particles having the desired particle size in a classification process using a centrifugal classifier such as Turboplex, Faculty, TSP, or TTSP Separator (manufactured by Hosokawa Micron Corporation), or an inertial classifier such as Elbow Jet (manufactured by Nittetsu Mining Co., Ltd.).

[0134] Heat treatment process Heat treatment may be performed after pulverization. Heat treatment can control the distribution of materials such as wax and make the toner spherical. Examples of heat treatment devices include the Hybridization System (manufactured by Nara Machinery Works), Mechanofusion System (manufactured by Hosokawa Micron Corporation), Faculty (manufactured by Hosokawa Micron Corporation), and Meteor Rainbow MR Type (manufactured by Nippon Pneumatic Co., Ltd.).

[0135] The heat treatment apparatus will be described with reference to the apparatus shown in Fig. 5. In the apparatus shown in Fig. 5, a mixture supplied at a fixed amount by a material supplying means 91 is introduced into an inlet pipe 93, which is installed vertically to the material supplying means, by compressed gas adjusted by a compressed gas adjusting means 92. The mixture passing through the inlet pipe is uniformly dispersed by a conical protruding member 94 installed in the center of the material supplying means, and is then introduced into eight-way supply pipes 95 that radiate outward, and into a treatment chamber 96 where heat treatment is carried out. At this time, the flow of the mixture supplied to the treatment chamber is regulated by a regulating means 99 installed in the treatment chamber for regulating the flow of the mixture.

[0136] Therefore, the mixture supplied to the treatment chamber is heat-treated while swirling within the treatment chamber, and then cooled. The hot air used to heat-treat the supplied mixture is supplied from hot air supply means 97, distributed by distribution member 912, and introduced into the treatment chamber by swirling member 913 for swirling the hot air in a spiral shape. In terms of configuration, swirling member 913 for swirling the hot air has multiple blades, and the swirling of the hot air can be controlled by the number and angle of the blades.

[0137] The hot air supplied into the processing chamber has a temperature at the outlet of the hot air supplying means 97 of 100° C. or higher and 300° C. or lower, more preferably 130° C. or higher and 170° C. or lower. If the temperature at the hot air supplying means outlet 911 is within the above range, it is possible to uniformly sphericalize the toner particles while preventing fusion and coalescence of the toner particles due to excessive heating of the mixture.

[0138] Furthermore, the heat-treated toner particles are cooled by cold air supplied from the cold air supply means 98, and the temperature of the cold air supplied from the cold air supply means 98 is preferably -20°C or higher and 30°C or lower. If the temperature of the cold air is within the above range, the heat-treated toner particles can be efficiently cooled, and fusion and coalescence of the heat-treated toner particles can be prevented without impeding the uniform spheroidization of the mixture. The absolute moisture content of the cold air is 0.5 g / m 3 More than 15.0g / m 3The cooled heat-treated toner particles are then collected by collection means 910 at the lower end of the processing chamber.

[0139] A blower (not shown) is provided beyond the recovery means, which is used for suction and transport. The powder particle supply port 914 is provided so that the swirling direction of the supplied mixture and the swirling direction of the hot air are the same, and the recovery means 910 of the surface treatment device is provided on the outer periphery of the treatment chamber so as to maintain the swirling direction of the swirled powder particles.

[0140] Furthermore, the cold air supplied from the cold air supply means 98 is supplied horizontally and tangentially from the outer periphery of the apparatus to the circumferential surface inside the processing chamber. The swirling direction of the toner supplied from the powder particle supply port 914, the swirling direction of the cold air supplied from the cold air supply means, and the swirling direction of the hot air supplied from the hot air supply means are all the same. This prevents turbulence from occurring inside the processing chamber, strengthens the swirling flow inside the apparatus, applies a strong centrifugal force to the toner, and further improves toner dispersibility, resulting in toner with fewer coalesced particles and more uniformly shaped toner.

[0141] ·External addition process Inorganic fine particles may be externally added to the surface of toner powder particles. The external addition step may be performed before, after, or both before and after the heat treatment step. The external addition step is performed by blending a predetermined amount of toner powder particles and a known external additive using a mixing device. Examples of mixing devices include a double cone mixer, V-type mixer, drum mixer, super mixer, Henschel mixer, Nauta mixer, Mechano Hybrid (manufactured by Nippon Coke Company), and Nobilta (manufactured by Hosokawa Micron Corporation).

[0142] ·Sieving process A sieving process may be carried out to remove coarse aggregates of additives and coarse particles formed in the heat treatment process. A sieving machine such as Ultrasonic (manufactured by Koei Sangyo Co., Ltd.), Resonaseave, Gyrosifter (manufactured by Tokuju Kogyosho Co., Ltd.), Turbo Screener (manufactured by Turbo Kogyo Co., Ltd.), or Hi-Bolter (manufactured by Toyo Hitec Co., Ltd.), or a classifier such as those listed in the classification process above, may be used.

[0143] - Toner production example - Examples of toner preparation using polyester resins L, H, and C are described below. Polyester resin L The following materials were weighed and placed in a reaction vessel equipped with a condenser, a stirrer, a nitrogen inlet tube, and a thermocouple. Polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane: 72.0 parts by mass (0.20 moles; 100.0 mole% based on the total number of moles of polyhydric alcohol) Terephthalic acid: 28.0 parts by mass (0.17 moles; 100.0 mole % based on the total number of moles of polycarboxylic acids) Tin 2-ethylhexanoate (esterification catalyst): 0.5 parts by mass

[0144] Next, the atmosphere inside the flask was replaced with nitrogen gas, and the temperature was gradually raised with stirring, and the mixture was allowed to react for 4 hours with stirring at a temperature of 200°C. The pressure inside the reaction vessel was then reduced to 8.3 kPa and maintained at this temperature for 1 hour, after which the mixture was cooled to 180°C and returned to atmospheric pressure. Trimellitic anhydride: 3 parts by mass (0.01 mole; 4.0 mol% based on the total number of moles of polycarboxylic acids) tert-butylcatechol (polymerization inhibitor): 0.1 parts by mass

[0145] Then, the above materials were added, the pressure in the reactor was reduced to 8.3 kPa, and the temperature was maintained at 180°C. After it was confirmed that the softening point measured in accordance with ASTM D36-86 had reached 90° C., the temperature was lowered to terminate the reaction, and an amorphous polyester resin L was obtained. Polyester resin H

[0146] The following materials were weighed and placed in a reaction vessel equipped with a condenser, a stirrer, a nitrogen inlet tube, and a thermocouple. Polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane: 72.3 parts by mass (0.20 moles; 100.0 mole% based on the total number of moles of polyhydric alcohol) Terephthalic acid: 18.3 parts by mass (0.11 moles; 65.0 mol% based on the total number of moles of polycarboxylic acids) Fumaric acid: 2.9 parts by mass (0.03 moles; 15.0 mole % based on the total number of moles of polycarboxylic acids) Tin 2-ethylhexanoate (esterification catalyst): 0.5 parts by mass

[0147] Next, the atmosphere in the flask was replaced with nitrogen gas, and the temperature was gradually raised with stirring, and the reaction was carried out for 2 hours with stirring at a temperature of 200°C. The pressure in the reaction vessel was then reduced to 8.3 kPa and maintained at this temperature for 1 hour, after which the pressure was cooled to 180 and returned to atmospheric pressure. Trimellitic anhydride: 6.5 parts by mass (0.03 moles; 20.0 mole% based on the total number of moles of polycarboxylic acids) tert-butylcatechol (polymerization inhibitor): 0.1 parts by mass

[0148] The above materials were then added, the pressure in the reaction vessel was reduced to 8.3 kPa, and the reaction was carried out for 15 hours while maintaining the temperature at 160° C. After confirming that the softening point measured in accordance with ASTM D36-86 had reached 137° C., the temperature was reduced to stop the reaction, and amorphous polyester resin H was obtained. Crystalline polyester resin C The following materials were weighed and placed in a reaction vessel equipped with a condenser, a stirrer, a nitrogen inlet tube, and a thermocouple. 1,6-Hexanediol: 34.5 parts by mass (0.29 moles; 100.0 mole% based on the total number of moles of polyhydric alcohols) Dodecanedioic acid: 65.5 parts by mass (0.28 moles; 100.0 mole% based on the total number of moles of polycarboxylic acids) Tin 2-ethylhexanoate: 0.5 parts by mass

[0149] After replacing the atmosphere in the flask with nitrogen gas, the temperature was gradually increased while stirring, and the mixture was allowed to react for 3 hours while stirring at a temperature of 140°C. Next, the above materials were added, the pressure in the reaction vessel was reduced to 8.3 kPa, and the mixture was allowed to react for 4 hours while maintaining the temperature at 200°C.

[0150] Furthermore, the pressure in the reactor was gradually released to return to normal pressure, and then one or more aliphatic compounds selected from the group shown in Table 2 were added in an amount of 7.0 mol% relative to 100.0 mol% of the raw material monomers, and the mixture was reacted at 200°C under normal pressure for 2 hours. The pressure in the reactor was then reduced to 5 kPa or less again, and the mixture was reacted at 200°C for 3 hours to obtain crystalline polyester resin C. The SP value (SP1) of crystalline polyester resin C was 11.3.

[0151] - Toner particle production The following materials were mixed in a Henschel mixer (FM-75, manufactured by Mitsui Mining Co., Ltd.) at a rotation speed of 20 s. -1 After mixing for 5 minutes, the mixture was kneaded in a twin-screw kneader (PCM-30 model, manufactured by Ikegai Corporation). The barrel temperature during kneading was set so that the outlet temperature of the kneaded product was 115°C. The outlet temperature of the kneaded product was directly measured using a handheld thermometer HA-200E manufactured by Anritsu Meter Co., Ltd. Amorphous polyester resin L 50 parts by mass Amorphous polyester resin H 50 parts by mass Crystalline polyester resin C 5 parts by mass Wax dispersant 5 parts by weight Fischer-Tropsch wax (hydrocarbon wax, maximum endothermic peak temperature 90°C) 5 parts by mass CI Pigment Blue 15:3 7 parts by weight 0.3 parts by mass of 3,5-di-t-butylsalicylic acid aluminum compound (Bontron E88, manufactured by Orient Chemical Industry Co., Ltd.)

[0152] The kneaded material obtained was cooled and coarsely pulverized to 1 mm or less using a hammer mill to obtain a coarsely pulverized material. The coarsely pulverized material obtained was finely pulverized using a mechanical pulverizer (T-250, manufactured by Turbo Kogyo Co., Ltd.). Further, classification was performed using a Faculty F-300 (manufactured by Hosokawa Micron Corporation) to obtain toner particles. The operating conditions were a classification rotor rotation speed of 130 s -1 , distributed rotor rotation speed 120s -1 It was decided.

[0153] The obtained toner particles were subjected to a heat treatment using the surface treatment device shown in Fig. 5 to obtain heat-treated toner particles. The operating conditions were a feed rate of 5 kg / hour, a hot air temperature of 150°C, and a hot air flow rate of 6 m 3 / min, cold air temperature = -5℃, cold air flow rate = 4m 3 / min, Blower air volume = 20m 3 / min, injection air flow rate = 1m 3 / min.

[0154] 100 parts by mass of the obtained heat-treated particles of the toner were mixed with hydrophobic silica (BET: 200m 2 / g) 1.0 mass part, titanium oxide fine particles surface-treated with isobutyltrimethoxysilane (BET: 80m 2 1.0 mass part of 1 / g) was mixed with a Henschel mixer (FM-75, manufactured by Mitsui Mining Co., Ltd.) at a rotation speed of 30 s -1 The mixture was mixed for 10 minutes, and the rotation time was 10 minutes to obtain toner particles.

[0155] <Magnetic Carrier of Developer> As the magnetic carrier, usable are surface-oxidized iron powder, unoxidized iron powder, metal particles such as iron, lithium, calcium, magnesium, nickel, copper, zinc, cobalt, manganese, and rare earth elements, alloy particles thereof, oxide particles, magnetic materials such as ferrite, and magnetic material-dispersed resin carriers in which magnetic materials are dispersed in a binder resin.

[0156] The preferred range of the physical properties of the magnetic carrier is a weight average particle size of 20 μm or more and 50 μm or less, preferably 30 μm or more and 40 μm or less. 7 Ω·cm or more, preferably 10 8 Ω·cm or more, and the magnetization is 40 emu / g or more and 80 emu / g or less. The magnetic material dispersed resin carrier consists of a magnetic carrier core and a coating resin.

[0157] <Magnetic carrier core manufacturing example> To 100.0 parts by mass of magnetite powder with a number-average particle size of 0.30 μm, 4.0 parts by mass of a silane coupling agent (3-(2-aminoethylamino)propyltrimethoxysilane) was added, and the mixture was mixed and stirred at high speed in a container at 100°C or higher to treat the fine particles. Phenol 10 parts by mass Formaldehyde solution 6 parts by weight (40% formaldehyde, 10% methanol, 50% water) Treated magnetite 84 parts by weight

[0158] The above materials, 5 parts by weight of 28% aqueous ammonia, and 20 parts by weight of water were placed in a flask, and the mixture was heated to 85°C over 30 minutes and held there while stirring and mixing. A polymerization reaction was carried out for 3 hours, and the resulting phenolic resin was cured. The cured phenolic resin was then cooled to 30°C, and more water was added. The supernatant was removed, and the precipitate was washed with water and air-dried. This was then dried at 60°C under reduced pressure (5 mmHg or less) to obtain spherical magnetic carrier cores with the magnetic material dispersed therein.

[0159] <Example of coating resin production> Chief Monomer Cyclohexyl methacrylate 69.5 parts by mass Methyl methacrylate 0.5 parts by mass Macromonomer Methyl methacrylate 30 parts by mass (The macromonomer has a terminal methacryloyl group as a reactive site having a reactive C—C double bond.) The above was added to a four-necked flask equipped with a reflux condenser, a thermometer, a nitrogen suction tube, and a rotary stirrer, and 100.0 parts by mass of toluene, 100.0 parts by mass of methyl ethyl ketone, and 2.4 parts by mass of azobisisovaleronitrile were further added, and the mixture was maintained at 80°C for 10 hours under a nitrogen stream to obtain a resin A-1 solution (solid content 35% by mass).

[0160] An autoclave was charged with 50 parts by mass of xylene, and after purging with nitrogen, the autoclave was heated to 185°C in a sealed state with stirring. A mixed solution of 99.99 parts by mass of styrene, 0.01 parts by mass of butyl acrylate, 50 parts by mass of di-t-butyl peroxide, and 20 parts by mass of xylene was continuously added dropwise over 3 hours while controlling the temperature inside the autoclave at 185°C, allowing polymerization to occur. The same temperature was maintained for another 1 hour to complete the polymerization, and the solvent was removed to obtain Resin B-1.

[0161] <Magnetic Carrier 1 Manufacturing Example> Magnetic carrier core 100 parts by mass ·Resin A-1 1.40 parts by mass ·Resin B-1 0.60 parts by mass The above-mentioned amount of coating resin was diluted with toluene to a resin content of 5% for 100 parts by mass of magnetic carrier cores, and the resulting solution was thoroughly stirred to prepare a resin solution. The magnetic carrier cores were then placed in a planetary mixer (Nauta Mixer VN, manufactured by Hosokawa Micron Corporation) maintained at 60°C, and the above-mentioned resin solution was added. The resin solution was added in half its original amount, and the solvent was removed and applied for 30 minutes. Next, another half of the resin solution was added, and the solvent was removed and applied for 40 minutes.

[0162] The magnetic carrier coated with the resin coating layer was then transferred to a mixer (a UD-AT type drum mixer manufactured by Sugiyama Heavy Industries Co., Ltd.) equipped with spiral blades in a rotatable mixing container, and heat-treated for 2 hours at 120°C in a nitrogen atmosphere while stirring at 10 revolutions per minute. The obtained magnetic carrier was separated into low magnetic particles by magnetic separation, passed through a sieve with 150 μm openings, and then classified with an air classifier to obtain the magnetic carrier.

[0163] -Example of developer production- The magnetic carrier and toner were mixed in a V-type mixer (V-10 type: Tokuju Seisakusho Co., Ltd.) for 0.5 seconds to achieve a toner concentration of 8.0% by mass. -1 The mixture was mixed for 5 minutes, and a magnetic two-component developer was obtained.

[0164] [Primary Transfer Means] The primary transfer unit is composed of the primary transfer roller 5 and intermediate transfer belt 8 shown in FIG. 1. The primary transfer roller 5 is composed of a core metal and a cylindrically formed conductive layer on its outer circumferential surface. Both ends of the primary transfer roller 5 are biased toward the electrophotographic photosensitive member 2 by pressing members (not shown) such as springs. As a result, the conductive layer of the primary transfer roller 5 is pressed against the surface of the electrophotographic photosensitive member 2 via the intermediate transfer belt 8 with a predetermined pressing force. A primary transfer bias power supply (not shown) serving as a primary transfer bias output unit is connected to the core metal. A primary transfer section is formed between the electrophotographic photosensitive member 2 and the primary transfer roller 5. The intermediate transfer belt 8 is sandwiched in the primary transfer section. The primary transfer roller 5 contacts the inner circumferential surface of the intermediate transfer belt 8 and rotates in accordance with the movement of the intermediate transfer belt 8. During image formation, a primary transfer bias voltage of a polarity (positive polarity, for example) opposite to the normal charging polarity (negative polarity, for example) of the toner is applied to the primary transfer roller 5 by the primary transfer bias power supply. Then, an electric field is formed between the primary transfer roller 5 and the electrophotographic photosensitive member 2 in a direction that moves the toner of the first polarity from the electrophotographic photosensitive member 2 toward the intermediate transfer belt 8. As a result, the toner image on the electrophotographic photosensitive member 2 is transferred (primary transfer) onto the surface of the intermediate transfer belt 8.

[0165] <Primary transfer roller> The primary transfer roller 5 may be either a sponge roller or a metal roller. The sponge roller is designed to have an appropriate electrical resistance value in order to apply an appropriate bias to the toner. When using a metal roller, instead of designing the electrical resistance value of the sponge, the roller may be positioned away from the position facing the drum. The sponge roller may have a core of 8 mm, an elastic layer of 4 mm, and an outer diameter of 16 mm. Examples of elastic materials include NBR and hydrin rubber.

[0166] (Intermediate transfer belt) The intermediate transfer belt 8 can be made of a dielectric resin such as polycarbonate, polyethylene terephthalate, or polyvinylidene fluoride. To improve transferability, the intermediate transfer belt 8 can have a laminated structure in which a surface layer is provided on a base layer. The structure is described below.

[0167] An example of an intermediate transfer belt having a single layer structure will be shown below. The intermediate transfer belt is made up of at least a resin and a conductive filler. Examples of resins include polyimide, polycarbonate, polyvinylidene fluoride (PVDF), polyphenylene sulfide, polyethylene, polypropylene, polystyrene, polyamide, polysulfone, and polyarylate. Also included are simple resins such as polyethylene terephthalate, polybutylene terephthalate, polyethersulfone, polyethernitrile, ethylene tetrafluoroethylene copolymer, and polyether ether ketone, or mixtures thereof.

[0168] The thickness of the intermediate transfer belt is preferably in the range of 40 to 200 μm. The surface resistivity of the intermediate transfer belt is preferably 1.0×10 9 Ω / □ or more 1.0×10 15 A range of Ω / □ can be suitably used (using a probe conforming to JIS-K6911 method, applied voltage 100V, application time 60 seconds, 23°C / 50%RH).

[0169] Conductive filler Examples of conductive fillers used in the base layer include carbon black and metal particles. Carbon black is preferred from the perspective of mechanical properties. Examples of carbon black include ketjen black, furnace black, acetylene black, thermal black, and gas black. Among these, acetylene black and furnace black are preferred because they contain fewer impurities, cause fewer foreign matter defects when molded into a film shape with the thermoplastic resin, and easily achieve the desired conductivity. Specific examples of acetylene black include the "Denka Black" series (manufactured by Denki Kagaku Kogyo Kabushiki Kaisha), the "Mitsubishi Conductive Filler" series (manufactured by Mitsubishi Chemical Corporation), the "Vulcan" series (manufactured by Cabot Corporation), the "Brintex" series (manufactured by Degussa), and "SRF" (manufactured by Asahi Carbon Co., Ltd.). Specific examples of furnace black include the "Toka Black" series (manufactured by Tokai Carbon Co., Ltd.) and the "Asahi Carbon Black" series (manufactured by Asahi Carbon Co., Ltd.).

[0170] [Cleaning Means] Adherents such as toner remaining on the surface of the electrophotographic photosensitive member 2 after the primary transfer step (primary transfer residual toner) are cleaned by a cleaning device 6. The cleaning device 6 is composed of a cleaning blade as a cleaning member for the electrophotographic photosensitive member, a waste toner transport screw, and a housing. The cleaning blade is brought into contact with the electrophotographic photosensitive member 2 at a predetermined angle and pressure by a pressure means (not shown). As a result, the toner remaining on the surface of the electrophotographic photosensitive member 2 is scraped off and removed from the electrophotographic photosensitive member 2 by the cleaning blade, and is collected in the housing. The collected toner is transported by the waste toner transport screw and discharged into a waste toner storage unit (not shown).

[0171] There are two methods for applying pressure to the cleaning blade 502: a fixed system and a spring pressure system. The fixed system generates pressure by mechanically intruding. The spring pressure system presses the blade against the electrophotographic photosensitive member using a spring. In the case of the fixed system, the angle between the electrophotographic photosensitive member and the tangent to the electrophotographic photosensitive member at the point of contact between the cleaning blade 502 and the electrophotographic photosensitive member is called the set angle. The preferred range for the set angle is 15° to 35°. Furthermore, the intruding amount (movement amount) d (FIG. 6) when intruding (moving) in the direction of contact with the photosensitive drum 501 is preferably 0.5 to 1.3 mm.

[0172] Urethane-based elastic materials are widely used as cleaning blade materials, and are used in the form of flat elastic materials supported by metal sheets. Cleaning blades are required to have toner-cleaning properties and abrasion resistance, and elastic materials with a Wallace hardness (measured by the M method (micro method) of the IRHD hardness test method) of 60 to 85 degrees and a rebound resilience of 10 to 40% are preferably used. The hardness and rebound resilience may be uniform throughout the blade, or may vary at the contact point with the electrophotographic photoreceptor or at the longitudinal end of the blade. Methods for varying the hardness and rebound resilience include two-color molding, in which a different material is bonded to the blade, and applying a curing agent and then heating to promote curing. When varying the hardness, it is preferable to vary only the hardness of the rubber surface.

[0173] The hardness of a rubber surface can be measured as follows to measure the hardness of only the surface vicinity. Using a Fischerscope HM2000LT microhardness tester (manufactured by Fischer), a Vickers square pyramidal diamond indenter with a facing angle of 136° is used in an environment of 25°C and 50% humidity, with an initial load of 0.14 mN / s and a final load of 0.98 mN. The final load of 0.98 mN is then maintained for 5 seconds, and the pressure is reduced to 0.14 mN / s. The indentation modulus obtained by measurement can be used as the hardness of the rubber surface.

[0174] [Secondary Transfer Means] The secondary transfer means comprises an electrically grounded secondary transfer counter roller 10 and a secondary transfer roller 12 connected to a secondary transfer bias power supply. During image formation, a secondary transfer bias voltage of a polarity (e.g., positive polarity) opposite to the normal charging polarity (e.g., negative polarity) of the toner is applied to the secondary transfer roller 12. An electric field is then formed between the secondary transfer counter roller 10 and the secondary transfer roller 12 in a direction that moves the toner of the normal charging polarity (e.g., negative polarity) from the intermediate transfer belt 8 toward the recording material P. As a result, the toner image on the intermediate transfer belt 8 is transferred (secondary transfer) onto the recording material P.

[0175] The secondary transfer opposing roller 10 is configured, for example, by providing an elastic layer made of EPDM (ethylene propylene diene rubber) around a metal core. The outer diameter is 15 mm, and the hardness of the elastic layer is set to, for example, 70°. The secondary transfer roller 12 is configured, for example, by providing an elastic layer made of NBR (nitrile rubber) or EPDM containing an ion conductive material such as a metal complex around a metal core, and is formed so that the outer diameter including the elastic layer is 14 mm. [Example]

[0176] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited to the following examples without departing from the gist of the present invention. In the following examples, "parts" are by mass unless otherwise specified.

[0177] Example 1 <Preparation of Electrophotographic Photoreceptor> -Support- As a support (conductive support), a cylindrical aluminum cylinder having a diameter of 29.9 mm, a length of 357.5 mm, and a thickness of 0.7 mm was used.

[0178] -Conductive layer- Next, 60 parts by mass of TiO particles coated with oxygen-deficient SnO as conductive particles, 36.5 parts by mass of phenolic resin as binder resin, and 20 parts by mass of methoxypropanol as solvent were dispersed for approximately one hour using a horizontal sand mill disperser with 1 mm diameter glass beads to prepare a dispersion. The TiO particles coated with oxygen-deficient SnO as conductive particles had a powder resistivity of 100 Ω·cm and a SnO coverage (mass ratio) of 40%. The phenolic resin was manufactured by Dainippon Ink and Chemicals, Inc. under the trade name Plyofen J-325, with a resin solids content of 60%. 18 kg of glass beads were added to the horizontal sand mill, and the dispersion disk rotation speed during dispersion was set to 900 rpm. The average particle size of the TiO2 particles coated with oxygen-deficient SnO2 in this dispersion was 0.36 μm.

[0179] To this dispersion, 1.5 parts by weight of silicone resin particles as a surface roughening agent and 0.001 parts by weight of silicone oil as a leveling agent were added and stirred to prepare a coating solution for the conductive layer. The silicone resin particles were manufactured by Momentive Performance Materials Japan, LLC under the trade name Tospearl (registered trademark) 120, with an average particle size of 2 μm. The silicone oil was manufactured by Dow Toray under the trade name SH28PA. This conductive layer coating solution was dip-coated onto a support, followed by drying and thermal curing at 150°C for 30 minutes to form a conductive layer with a thickness of 18 μm. The Rzjis of the conductive layer surface was measured to be 0.9 μm. Rzjis was measured in accordance with JIS-B0601 (1994) using a surface roughness meter, Surfcorder SE3500, manufactured by Kosaka Laboratory Ltd., with a feed rate of 0.1 mm / s, a cutoff λc of 0.8 mm, and a measurement length of 2.50 mm.

[0180] - Undercoat layer - Methoxymethylated nylon 6 resin 40 parts by mass (Product name: Torezin EF-30T, manufactured by Nagase ChemteX Corporation) The above-mentioned conductive layer was dip-coated with a solution prepared by dissolving the compound in a mixture of 400 parts by mass of methanol and 200 parts by mass of butanol, and the solution was dried by heating in a hot air dryer adjusted to 100°C for 30 minutes to harden the coating film of the solution, thereby forming an undercoat layer with a thickness of 0.5 μm.

[0181] -Charge generation layer- The following four materials were placed in a sand mill using glass beads with a diameter of 1 mm and dispersed for 4 hours, after which 700 parts by mass of ethyl acetate was added to prepare a coating liquid for a charge generating layer. Hydroxygallium phthalocyanine crystal (charge generating material) in a crystalline form having strong peaks at 7.4° and 28.2° of the Bragg angle 2θ±0.2° in CuKα characteristic X-ray diffraction: 20 parts by mass Polyvinyl butyral (product name: S-LEC (registered trademark) BBX-1, manufactured by Sekisui Chemical Co., Ltd.): 10 parts by mass A compound represented by the following formula (A): 0.2 parts by mass Cyclohexanone: 600 parts by mass This charge generating layer coating liquid was dip coated onto the undercoat layer, and the resulting coating was dried at 110° C. for 15 minutes to form a charge generating layer having a thickness of 0.20 μm. [ka]

[0182] -Charge transport layer- Next, 10 parts by weight of a compound represented by the following formula (B), 22.5 parts by weight of a compound represented by the above formula (C-1), 45 parts by weight of a compound represented by the above formula (C-2), 22.5 parts by weight of a compound represented by the above formula (C-3), 100 parts by weight of a polycarbonate resin (trade name: Iupilon (registered trademark) Z400, manufactured by Mitsubishi Engineering-Plastics Corporation, bisphenol Z type), and 0.18 parts by weight of a polycarbonate (viscosity average molecular weight Mv: 40,000) having a structural unit represented by the following formula (E) were dissolved in a solvent of 200 parts by weight of mixed xylene, 400 parts by weight of dimethoxymethane, and 200 parts by weight of methyl benzoate to prepare a coating solution for a charge transport layer. [ka] [ka] (In formula (E), 0.95 and 0.05 are the molar ratios (copolymerization ratios) of the two structural units.) This charge transport layer coating liquid was dip coated onto the charge generating layer to form a coating film, and the resulting coating film was dried at 105° C. for 30 minutes to form a charge transport layer with a thickness of 15 μm.

[0183] -Protective layer- 8.75 parts by mass of a compound represented by formula (1-3) 16.25 parts by mass of the compound represented by formula (2-1) Siloxane-modified acrylic resin 0.1 parts by mass (US270, manufactured by Toagosei Co., Ltd.) These were mixed with a solvent of 12 parts by mass of 1-propanol and 27 parts by mass of cyclohexane and stirred to prepare a coating liquid for the protective layer.

[0184] This protective layer coating solution was dip-coated onto the charge transport layer to form a coating film. The resulting coating film was dried at 40°C for 5 minutes. Next, under a nitrogen atmosphere, the substrate (irradiated object) was rotated at a speed of 300 rpm under conditions of an acceleration voltage of 70 kV and a beam current of 8.0 mA. The coating film was then irradiated with an electron beam for 1.5 seconds. The temperature of the coating film was then raised from 25°C to 115°C over 10 seconds to cure the coating film. The absorbed dose of the electron beam was measured at this time to be 15 kGy, and the oxygen concentration from electron beam irradiation to the subsequent heat treatment was 20 ppm or less. Next, the substrate was heat-treated at 100°C for 15 minutes to form a surface layer (protective layer) with a thickness of 5 μm.

[0185] <Rmax measurement> The Rmax of the produced electrophotographic photosensitive member was measured using a surface roughness measuring instrument, Surfcorder SE3500, manufactured by Kosaka Laboratory Co., Ltd., in accordance with JIS B0601 (1982). Measurement conditions Detector: R2μm Stylus: 0.7mN diamond stylus Filter: 2CR Cutoff value: 0.08 mm Measurement length: 2.5 mm Feed speed: 0.1 mm

[0186] <Evaluation of White Dots (Evaluation of Toner Melting)> The electrophotographic photoreceptor thus produced was evaluated for toner fusion adhesion by modifying a multifunction printer (product name: iR-ADVC3330, manufactured by Canon Inc.) as follows. Charging means DC bias: -1280V

[0187] Developing method The two-component developer consisting of non-magnetic toner and magnetic carrier, as described in the "Developer Preparation Example" above, was used, and the developing device described above was used. In particular, an aluminum developing sleeve with a V-shaped groove and a stainless steel layer thickness regulating member were used, and the gap between the developing sleeve 41 and the blade was set to 300 μm. An AC bias with a frequency of 10 kHz and an amplitude of 1.5 kV was used.

[0188] Primary transfer means A sponge roller with an outer diameter of 16 mm was used as the primary transfer roller. Cleaning means A urethane rubber blade with a length of 330 mm, a thickness of 2 mm, a Wallace hardness of 77 degrees, and a resilience of 20% was attached to a sheet metal member with a free length of 8 mm, and was fixed with a set angle of 18° and a penetration amount of 0.8 mm. In addition, only the area near the contact point of the urethane rubber blade with the electrophotographic photosensitive member was immersed in isocyanate within a range of 100 μm in the depth direction and hardened, thereby changing the hardness.

[0189] A photosensitive member was installed in the M station of the modified machine and fusion evaluation was performed. 20,000 horizontal line images with an image duty of 10% were continuously output in an environment of 30°C and 80%. Following the continuous output test, a solid black image was output. The output image was visually inspected to check the number of white dots within the circumferential distance of the electrophotographic photosensitive member 2.

[0190] The evaluation criteria for white spots due to toner fusion are as follows: A: No white spots B: One white dot C: 2 to 4 white dots

[0191] <Evaluation of image streaks (evaluation of external additive penetration)> The produced electrophotographic photoreceptor was evaluated for slip-through. A main body having the same configuration as the multifunction machine used in the toner fusion test was used. In a high-temperature, high-humidity environment of 30°C and 80% RH, 1,000 sheets of A4-sized plain paper were printed with a 5% print ratio. The charging conditions were a dark potential of -700 V, and the exposure conditions were an image exposure light intensity of 0.20 μJ / cm. 2 Subsequently, evaluation was performed using halftone images. Specifically, the number of streaks in the halftone images caused by toner passing through due to poor cleaning was visually counted and evaluated according to the following criteria. A: There are no streaks in the image quality and the image quality is good. B: Very slight streaks occur. C: Slight streaks occur.

[0192] The results are shown in Table 1. In the evaluation of white spots (evaluation of toner fusion) and the evaluation of image streaks (evaluation of external additive slip-through), a rating of A or B was determined to be effective.

[0193] Example 2 A charge transport layer was formed in the same manner as in Example (1), except that the amount of the compound represented by formula (C-1) contained in the charge transport layer coating liquid was changed to 17.5 parts by mass, the amount of the compound represented by formula (C-2) was changed to 35 parts by mass, the amount of the compound represented by formula (C-3) was changed to 17.5 parts by mass, 0.035 parts by mass of the compound represented by formula (C-5) was added, 0.07 parts by mass of the compound represented by formula (C-6) was added, and 0.035 parts by mass of the compound represented by formula (C-7) was added. In preparing the protective layer coating liquid for the electrophotographic photoreceptor, a protective layer was formed in the same manner as in Example 1, except that the amount of the compound represented by formula (1-3) was changed to 6.25 parts by mass and the amount of the compound represented by formula (2-1) was changed to 18.75 parts by mass, and an electrophotographic photoreceptor was produced. Evaluations were performed in the same manner as in Example 1.

[0194] Example 3 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that in the preparation of the coating solution for the protective layer of the electrophotographic photoreceptor, the amount of the compound represented by formula (1-3) was changed to 10 parts by mass, and the amount of the compound represented by formula (2-1) was changed to 15 parts by mass, and the electrophotographic photoreceptor was evaluated in the same manner as in Example 1.

[0195] Example 4 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the siloxane-modified acrylic resin was not added in preparing the coating liquid for the protective layer of the electrophotographic photoreceptor, and evaluations were performed in the same manner as in Example 1.

[0196] Example 5 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that in the preparation of the coating solution for the protective layer of the electrophotographic photoreceptor, the amount of the compound represented by formula (1-3) was changed to 2.5 parts by mass, and the amount of the compound represented by formula (2-1) was changed to 22.5 parts by mass, and the electrophotographic photoreceptor was evaluated in the same manner as in Example 1.

[0197] Example 6 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that in the preparation of the coating solution for the protective layer of the electrophotographic photoreceptor, the amount of the compound represented by formula (1-3) was changed to 12.5 parts by mass, and the amount of the compound represented by formula (2-1) was changed to 12.5 parts by mass, and the electrophotographic photoreceptor was evaluated in the same manner as in Example 1.

[0198] Example 7 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that in the preparation of the coating solution for the protective layer of the electrophotographic photoreceptor, the amount of the compound represented by the above formula (1-3) was changed to 12.5 parts by mass, and the amount of the compound represented by the above formula (2-1) was changed to 12.5 parts by mass. In order to roughen (roughen) the surface layer of the electrophotographic photosensitive member produced above, the electrophotographic photosensitive member was subjected to a polishing treatment using the polishing device shown in Fig. 1. The polishing conditions were as follows. Abrasive sheet: GC#2000 or CG#3000 (manufactured by Riken Corundum Co., Ltd.) Abrasive sheet feed speed: 300 mm / min Electrophotographic photoreceptor rotation speed: 300 rpm Rotation direction of the abrasive sheet and electrophotographic photoreceptor: Backup roller: outer diameter 100 mm, Asker C hardness 25 The electrophotographic photosensitive member was pressed against the backup roller by 1.0 mm, and polishing was carried out for 4 seconds. After polishing, the Rmax of the electrophotographic photosensitive member was measured in the same manner as in Example 1, and evaluation was carried out in the same manner as in Example 1.

[0199] (Comparative Example 1) An electrophotographic photosensitive member was produced in the same manner as in Example 1, except that in the preparation of the coating solution for the protective layer of the electrophotographic photosensitive member, the amount of the compound represented by formula (1-3) was changed to 1.25 parts by mass and the amount of the compound represented by formula (2-1) was changed to 23.75 parts by mass, and the electrophotographic photosensitive member was evaluated in the same manner as in Example 1.

[0200] (Comparative Example 2) An electrophotographic photosensitive member was produced in the same manner as in Example 1, except that in the preparation of the coating solution for the protective layer of the electrophotographic photosensitive member, the amount of the compound represented by formula (1-3) was changed to 15 parts by mass, and the amount of the compound represented by formula (2-1) was changed to 10 parts by mass, and the electrophotographic photosensitive member was evaluated in the same manner as in Example 1.

[0201] (Comparative Example 3) An electrophotographic photoreceptor was produced in the same manner as in Example 1. The polishing treatment was carried out in the same manner as in Example 6, except that the polishing time in the polishing treatment carried out in the example was changed to 10 seconds, and evaluation was carried out in the same manner as in Example 1.

[0202] [Table 1]

[0203] The disclosure of this embodiment includes the following configuration. (Configuration 1) an electrophotographic photoreceptor; a charging means for charging the surface of the electrophotographic photosensitive member; an image exposure means for irradiating the surface of the electrophotographic photosensitive member with image exposure light to form an electrostatic latent image on the surface of the electrophotographic photosensitive member; a developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member using a two-component developer having a toner and a magnetic carrier to form a toner image on the surface of the electrophotographic photosensitive member; a cleaning means for cleaning residual toner from the surface of the electrophotographic photosensitive member; a transfer means for transferring the toner image formed on the surface of the electrophotographic photosensitive member onto a recording medium; An electrophotographic apparatus having The electrophotographic photoreceptor has a surface layer having a copolymer of a composition containing a compound represented by the following general formula (1) and a compound represented by the following general formula (2), The content of the compound represented by the following general formula (1) in the composition is 10% by mass or more and 50% by mass or less with respect to the total content of the compound represented by the general formula (1) and the compound represented by the general formula (2), The surface of the surface layer has a maximum height roughness Rmax of 0.30 μm or less as specified in JIS B0601:1982. An electrophotographic apparatus characterized by: [ka] (In general formula (1), R1, R2, R3, and R4 each represent a hydrogen atom or a methyl group, and p represents an integer of 2 or more and 5 or less.) [ka] (In general formula (2), R5 and R6 each represent a hydrogen atom or a methyl group, and q represents an integer of 2 or more and 5 or less.) (Configuration 2) The electrophotographic device according to Configuration 1, wherein the content of the compound represented by the general formula (1) in the composition is 25% by mass or more and 40% by mass or less with respect to the total content of the compound represented by the general formula (1) and the compound represented by the general formula (2). (Configuration 3) 3. The electrophotographic apparatus according to configuration 1 or 2, wherein the compound represented by the general formula (1) is a compound represented by the following formula (1-3): [ka] (Configuration 4) 4. The electrophotographic apparatus according to any one of configurations 1 to 3, wherein the compound represented by the general formula (2) is a compound represented by the following formula (2-1): [ka] (Configuration 5) 5. The electrophotographic apparatus according to any one of Configurations 1 to 4, wherein the composition does not contain fluorine atom-containing resin particles. (Configuration 6) 6. The electrophotographic apparatus according to any one of Configurations 1 to 5, wherein the surface layer contains a siloxane-modified acrylic resin. [Explanation of symbols]

[0204] 1, 1Y, 1M, 1C, 1Bk image forming unit, 2, 2Y, 2M, 2C, 2Bk electrophotographic photosensitive member, 3, 3Y, 3M, 3C, 3Bk charging roller, 4, 4Y, 4M, 4C, 4Bk developing unit, 5, and 5Y, 5M, 5C, 5Bk primary transfer roller, 6, 6Y, 6M, 6C, 6Bk cleaning device, 7, 7Y, 7M, 7C, 7Bk image exposure device, 8 intermediate transfer belt, 9 drive roller, 10 secondary transfer opposing roller, 11 driven roller, 12 secondary transfer roller, 13 supply roller, 14 fixing device, 15 intermediate transfer belt cleaner, P recording material, 301 conductive core metal, 302 elastic layer, 41 developer carrier, 42 toner concentration detection means, 43a first stirring and conveying screw, 43b Second stirring and conveying screw, 44 developing container, 44a developing chamber, 44b stirring chamber, 44c toner supply port, 44d partition wall, 45 toner remaining amount detecting means, 46 toner container, 47 toner supply screw, 48 toner discharge port, 49 toner supply device, 51 developer carrier drive motor, 52 stirring and conveying screw drive motor, 53 toner supply screw drive motor, 54 gear for transmitting drive of toner supply screw, 60 engine control section, 61 CPU (control means), 62 ROM, 91 raw material constant amount supply means, 910 recovery means, 911 hot air supply means outlet, 912 distribution member, 913 swiveling member, 914 powder particle supply port, 92 compressed air adjustment means, 93 introduction pipe, 94 protruding member, 95 supply pipe, 96 treatment chamber, 97 hot air supply means, 98 cold air supply means, 99 regulation means

Claims

1. an electrophotographic photoreceptor; a charging means for charging the surface of the electrophotographic photosensitive member; an image exposure means for irradiating the surface of the electrophotographic photosensitive member with image exposure light to form an electrostatic latent image on the surface of the electrophotographic photosensitive member; a developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member using a two-component developer having a toner and a magnetic carrier to form a toner image on the surface of the electrophotographic photosensitive member; a cleaning means for cleaning residual toner from the surface of the electrophotographic photosensitive member; a transfer means for transferring the toner image formed on the surface of the electrophotographic photosensitive member onto a recording medium; An electrophotographic apparatus having The electrophotographic photoreceptor has a surface layer having a copolymer of a composition containing a compound represented by the following general formula (1) and a compound represented by the following general formula (2), the content of the compound represented by the following general formula (1) in the composition is 10% by mass or more and 50% by mass or less with respect to the total content of the compound represented by the general formula (1) and the compound represented by the general formula (2), The surface of the surface layer has a maximum height roughness Rmax of 0.30 μm or less as specified in JIS B0601:1982. An electrophotographic apparatus characterized by: 【Chemical 1】 (In general formula (1), R1, R2, R3, and R4 each represent a hydrogen atom or a methyl group, and p represents an integer of 2 or more and 5 or less.) 【Chemistry 2】 (In general formula (2), R5 and R6 each represent a hydrogen atom or a methyl group, and q represents an integer of 2 or more and 5 or less.)

2. 2. The electrophotographic device according to claim 1, wherein the content of the compound represented by the general formula (1) in the composition is 25% by mass or more and 40% by mass or less with respect to the total content of the compound represented by the general formula (1) and the compound represented by the general formula (2).

3. 2. The electrophotographic apparatus according to claim 1, wherein the compound represented by the general formula (1) is a compound represented by the following formula (1-3): 【Chemistry 3】

4. 2. The electrophotographic apparatus according to claim 1, wherein the compound represented by the general formula (2) is a compound represented by the following formula (2-1): 【Chemistry 4】

5. 2. The electrophotographic apparatus according to claim 1, wherein the composition does not contain fluorine atom-containing resin particles.

6. 2. The electrophotographic apparatus according to claim 1, wherein the surface layer contains a siloxane-modified acrylic resin.

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