Electrophotographic photoreceptor, process cartridge, electrophotographic apparatus, and method for manufacturing electrophotographic photoreceptor

Abstract

To provide an electrophotographic photoreceptor which comprises a surface layer that features superior dispersibility of fluorine atom-containing resin particles and suppresses electric potential variations associated with repetitive use.SOLUTION: An electrophotographic photoreceptor is provided, comprising a surface layer containing fluorine atom-containing resin particles, a binder resin, and a polymer having a specific repeating unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member, and a method for manufacturing the electrophotographic photosensitive member. [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) of electrophotographic photoreceptors in order to extend their lifespan and achieve high image quality during repeated use.

[0003] One technique for improving the abrasion resistance of an electrophotographic photosensitive member is to incorporate fluorine atom-containing resin particles into the surface layer of the electrophotographic photosensitive member, thereby reducing friction between the surface layer and a contact member such as a cleaning blade. Patent Document 1 discloses a technique for forming a surface layer using a dispersion of fluorine atom-containing resin particles such as polytetrafluoroethylene resin particles as a coating liquid for the surface layer.

[0004] Furthermore, when preparing a dispersion of fluorine-containing resin particles, a method is known in which a fluorine-containing (meth)acrylic polymer is used as a dispersant for the fluorine-containing resin particles in order to improve dispersibility. Patent Documents 2 and 3 disclose techniques for improving the dispersibility of fluorine-containing resin particles by using a fluorine-containing (meth)acrylic polymer with a specific structure as a dispersant.

[0005] Patent Document 4 discloses an electrophotographic photoreceptor having an outermost surface layer containing a fluorine-based graft polymer and fluorine-containing resin particles, in which the fluorine-based graft polymer contains a structural unit having an acidic group with a pKa of 3 or less. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 06-332219 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-189715 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-104145 [Patent Document 4] Patent Publication No. 2021-47236 Summary of the Invention [Problem to be solved by the invention]

[0007] However, while the techniques disclosed in Patent Documents 2 and 3 provide a surface layer with excellent dispersibility of fluorine-containing resin particles, they sometimes fail to sufficiently suppress potential fluctuations during repeated use of the electrophotographic photoreceptor. In particular, electrophotographic photoreceptors having a surface layer with excellent abrasion resistance for the purpose of extending their lifespan have a problem of large potential fluctuations during long-term repeated use. Therefore, there is room for improvement in suppressing potential fluctuations during repeated use of the electrophotographic photoreceptor.

[0008] One aspect of the present disclosure is to provide an electrophotographic photoreceptor in which potential fluctuations during repeated use are suppressed. Another aspect of the present disclosure is directed to providing a process cartridge in which the electrophotographic photosensitive member is mounted, and an electrophotographic apparatus equipped with the process cartridge. Another aspect of the present disclosure is directed to providing a method for producing the electrophotographic photoreceptor. [Means for solving the problem]

[0009] According to one aspect of the present disclosure, there is provided an electrophotographic photoreceptor having a surface layer, the surface layer comprising fluorine atom-containing resin particles, a binder material, and a structural unit represented by the following formula (1): and a structural unit represented by the following formula (2): and the polymer A does not have a structural unit having an acidic group having a pKa of 3 or less. An electrophotographic photoreceptor is provided, characterized in that: [ka] ( the above In formula (1), R 11 represents a hydrogen atom or a methyl group. 12 represents a single bond or a methylene group. 1 and Rf 2 Rf each independently represents a perfluoroalkylene group having 1 to 3 carbon atoms or a perfluoroalkylidene group having 1 to 3 carbon atoms. 3 represents a perfluoroalkyl group having 1 to 3 carbon atoms. (In the above formula (2), Y A1 represents an unsubstituted alkylene group, and Y B represents an unsubstituted alkylene group, an alkylene group substituted with a halogen atom, an alkylene group substituted with a hydroxy group, an ester bond (-COO-), an amide bond (-NHCO-), a urethane bond (-NHCOO-), or a divalent linking group derived by combining one or more selected from these groups and bonds with -O- or -S-, or a single bond; Z A is a structure represented by the following formula (2A) (Z A1 represents an alkyl group having 1 to 4 carbon atoms; R represents a cyano group or a phenyl group; 21 and R 22 each independently represents a hydrogen atom or a methyl group, and m is an integer of 25 or more and 150 or less. According to another aspect of the present disclosure, there is provided an electrophotographic photoreceptor having a surface layer, the surface layer containing fluorine atom-containing resin particles, a binder material, and a polymer A having a structural unit represented by the above formula (1), the content of the polymer A being 2% by mass or more and 10% by mass or less relative to the mass of the fluorine atom-containing resin particles in the surface layer, and the polymer A not having a structural unit having an acidic group with a pKa of 3 or less. According to yet another aspect of the present invention, there is provided an electrophotographic photoreceptor having a surface layer, the surface layer comprising fluorine atom-containing resin particles, a binder material, and a polymer A having a structural unit represented by the above formula (1), wherein the content of the structural unit represented by the formula (1) in the polymer A is from 5% to 95% by number based on the total structural units in the polymer A, and the polymer A does not have a structural unit having an acidic group with a pKa of 3 or less.

[0010] The surface layer preferably does not contain a polymer having a structural unit with an acidic group having a pKa of 3 or less.

[0011] According to another aspect of the present disclosure, there is provided a process cartridge that integrally supports the electrophotographic photosensitive member and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means, and is detachably attachable to the main body of an electrophotographic apparatus. According to another aspect of the present disclosure, there is provided an electrophotographic apparatus having the electrophotographic photoreceptor, a charging unit, an exposure unit, a developing unit, and a transfer unit. According to another aspect of the present disclosure, there is provided a method for producing the electrophotographic photoreceptor. [Effects of the Invention]

[0012] According to one aspect of the present disclosure, it is possible to provide an electrophotographic photoreceptor in which the dispersibility of fluorine atom-containing resin particles in the surface layer is excellent and potential fluctuation during repeated use is suppressed. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 2 is a schematic diagram illustrating an example of the configuration of an electrophotographic photosensitive member. [Figure 2] FIG. 1 is a diagram showing an example of a polishing machine using a polishing sheet. [Figure 3] 1 is a diagram showing an example of a schematic configuration of a process cartridge in which an electrophotographic photosensitive member is mounted, and an electrophotographic apparatus including the process cartridge. [Figure 4] FIG. 1 is a schematic view illustrating an example of a process cartridge having an electrophotographic photosensitive member. [Figure 5] 1 is a schematic diagram illustrating an example of an electrophotographic apparatus having an electrophotographic photosensitive member. DETAILED DESCRIPTION OF THE INVENTION

[0014] As a result of investigations by the present inventors, it has been found that by incorporating fluorine atom-containing resin particles, a binder material, and a polymer A having a structural unit represented by the following formula (1) into the surface layer of an electrophotographic photoreceptor, The surface layer has excellent dispersibility of fluorine-containing resin particles, and Potential fluctuations during repeated use are suppressed It has been found that an electrophotographic photoreceptor can be obtained. [ka] (In formula (1), R 11 represents a hydrogen atom or a methyl group. 12 represents a single bond or a methylene group. 1 and Rf 2 Rf each independently represents a perfluoroalkylene group having 1 to 3 carbon atoms or a perfluoroalkylidene group having 1 to 3 carbon atoms. 3 represents a perfluoroalkyl group having 1 to 3 carbon atoms.

[0015] The polymer A does not have a structural unit having an acidic group with a pKa of 3 or less. The surface layer may or may not contain a polymer having a structural unit with an acidic group having a pKa of 3 or less, but it is preferable that the surface layer does not contain such a polymer.

[0016] The pKa of an acidic group can be determined by measurement using a known method such as titration. Examples of acidic groups with a pKa of 3 or less include a sulfonic acid group (methanesulfonic acid: -2.6), a phosphonic acid group (first dissociation: 1.5), a phosphoric acid group (first dissociation: 2.12), and a fluorinated alkylcarboxylic acid group (e.g., trifluoroacetic acid: -0.25, difluoroacetic acid: 1.24, monofluoroacetic acid: 2.66).

[0017] The present inventors believe that the polymer A having the structural unit represented by the formula (1) functions as a dispersant for fluorine atom-containing resin particles in the process of preparing a surface layer coating liquid for forming the surface layer of an electrophotographic photosensitive member.

[0018] The present inventors speculate as follows why the electrophotographic photoreceptor of the present disclosure has excellent dispersibility of fluorine atom-containing resin particles in the surface layer and excellent effect of suppressing potential fluctuations during repeated use.

[0019] Electrophotographic photoreceptors having a surface layer containing fluorine-containing resin particles and a dispersant tend to have large potential fluctuations during repeated use. This is due to the -(CF2) of the dispersant attached to the fluorine-containing resin particles contained in the surface layer. n -This is thought to be because electric charges tend to accumulate in the chains.

[0020] As a result of the investigations by the present inventors, -(CF2) n When the surface layer contains a polymer having a structural unit containing a - chain, -(CF2) n -Chain and-(CF2) nIt was found that the presence of an oxygen atom between the -(CF2) chain has the effect of suppressing charge trapping. n The greater the number of carbon atoms in the chain, the more easily electric charges accumulate, and in some cases the effect of suppressing potential fluctuations may not be sufficient.

[0021] Therefore, as a result of further investigations by the present inventors, it was found that by incorporating polymer A having a structural unit represented by the above formula (1) into the surface layer, charge trapping can be suppressed and an electrophotographic photoreceptor in which potential fluctuation during repeated use is suppressed can be obtained.

[0022] Rf in the formula (1) 1 and Rf 2 is a perfluoroalkylene group having 1 to 3 carbon atoms or a perfluoroalkylidene group having 1 to 3 carbon atoms, and Rf 3 is a perfluoroalkyl group having 1 to 3 carbon atoms. By doing so, it is thought that accumulation of electric charge in the structural unit represented by the formula (1) can be suppressed. 12 By making the structural unit represented by formula (1) a single bond or a methylene group, the difference in surface energy between the structural unit represented by formula (1) and the fluorine-containing resin particles is thought to be small, making it easier to adhere to the fluorine-containing resin particles.

[0023] <Fluorine atom-containing resin particles> The surface layer of the electrophotographic photoreceptor of the present disclosure contains fluorine atom-containing resin particles, and the content of the fluorine atom-containing resin particles in the surface layer is preferably 5% by mass or more and 40% by mass or less relative to the total mass of the surface layer. Examples of resins contained in the fluorine atom-containing resin particles used in the present disclosure include the following: polytetrafluoroethylene resin, polychlorotrifluoroethylene resin, polytetrafluoroethylenepropylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, and polydichlorodifluoroethylene resin. It is also preferable to use particles containing multiple types of the above resins. Among the above, from the viewpoint of improving dispersibility, it is more preferable that the fluorine atom-containing resin particles be polytetrafluoroethylene (PTFE) resin.

[0024] In cross-sectional observation of the surface layer, the fluorine atom-containing resin particles preferably have an arithmetic mean of the major axes of the primary particles (average primary particle size) measured from a secondary electron image taken with a scanning electron microscope of 150 nm to 300 nm in terms of improving dispersibility and suppressing potential fluctuations.Furthermore, the fluorine atom-containing resin particles preferably have an average primary particle size of 180 nm to 250 nm.

[0025] The fluorine atom-containing resin particles preferably have an average circularity (average circularity) of 0.75 or more, calculated from the area and perimeter of primary particles measured from a secondary electron image taken by a scanning electron microscope.

[0026] In order to ensure that the average primary particle size and average circularity of the fluorine atom-containing resin particles contained in the surface layer of the electrophotographic photoreceptor of the present disclosure fall within the above ranges, fluorine atom-containing resin particles can be used such that the average primary particle size and average circularity values ​​calculated by the following methods fall within the above ranges.

[0027] (Method for measuring average primary particle size and average roundness) That is, in the examples of the present disclosure, the average particle size and average circularity of the fluorine-containing resin particles contained in the surface layer of the electrophotographic photoreceptor were measured using a field emission scanning electron microscope (FE-SEM) as follows: The fluorine-containing resin particles were attached to commercially available carbon conductive tape, and the fluorine-containing resin particles not attached to the conductive tape were removed with compressed air, followed by platinum deposition. The deposited fluorine-containing resin particles were observed using an FE-SEM (S-4700) manufactured by Hitachi High-Technologies Corporation. The FE-SEM measurement conditions were as follows: Accelerating voltage: 2 kV WD: 5mm Magnification: 20,000 times Number of pixels: 1280 pixels vertically, 960 pixels horizontally (size of each pixel: 5 nm) From the obtained images, the Feret's diameter of 100 particles was determined using ImageJ (open source software from the National Institutes of Health (NIH)), and the average value was calculated to obtain the average particle size. Similarly, the area and circumference were determined, and the circularity was calculated from the following formula (II), and the average value was calculated to obtain the average circularity. Circularity = 4 × π × (area) ÷ (perimeter squared) Formula (II)

[0028] The fluorine atom-containing resin particles of the present disclosure may be used alone or in combination of two or more types.

[0029] <Polymer A having a structural unit represented by formula (1)> The surface layer of the electrophotographic photoreceptor of the present disclosure contains a polymer A having a structural unit represented by the following formula (1). [ka]

[0030] In the formula (1), R 11 is a hydrogen atom or a methyl group. 12 is a single bond or a methylene group. 12When Rf is an alkylene having two or more carbon atoms, the difference in surface energy between the structural unit represented by the formula (1) and the fluorine-containing resin particles becomes large, making it difficult for the structural unit to adhere to the fluorine-containing resin particles sufficiently, and dispersibility tends to be insufficient. 1 and Rf 2 Rf are each independently a perfluoroalkylene group having 1 to 3 carbon atoms or a perfluoroalkylidene group having 1 to 3 carbon atoms. 3 Rf is a perfluoroalkyl group having 1 to 3 carbon atoms. 1 ~Rf 3 If the number of carbon atoms is 4 or more, accumulation of electric charge in the structural unit represented by the formula (1) cannot be sufficiently suppressed, and potential fluctuations cannot be sufficiently suppressed during repeated use of the electrophotographic photosensitive member.

[0031] In addition, in the formula (1), Rf 1 ~Rf 3 The total number of carbon atoms in Rf is preferably 6 or more and 9 or less from the viewpoint of improving the dispersibility of the fluorine atom-containing resin particles. 1 ~Rf 3 The total number of carbon atoms is more preferably 6 or more and 8 or less.

[0032] Examples of the structural unit represented by formula (1) contained in polymer A having the structural unit represented by formula (1) used in the present disclosure include the structures shown in Table 1 below.

[0033] [Table 1]

[0034] In order to improve the dispersibility of fluorine-containing resin particles, the content of the structural unit represented by formula (1) in the polymer A contained in the surface layer of the electrophotographic photoreceptor of the present disclosure is preferably 5% by number to 95% by number (0.1% by mass to 80% by mass) of all structural units contained in the polymer A. Furthermore, the content of the structural unit represented by formula (1) is more preferably 50% by number to 95% by number (1% by mass to 80% by mass) of all structural units contained in the polymer A. Furthermore, the content of the structural unit represented by formula (1) is more preferably 70% by number to 90% by number (4% by mass to 66% by mass) of all structural units contained in the polymer A.

[0035] The weight-average molecular weight of the polymer A having the structural unit represented by formula (1) contained in the surface layer of the electrophotographic photoreceptor of the present disclosure is preferably 16,000 or more and 100,000 or less, from the viewpoints of improving the dispersibility of the fluorine atom-containing resin particles and suppressing potential fluctuations.Moreover, the weight-average molecular weight of the polymer A having the structural unit represented by formula (1) is more preferably 18,000 or more and 80,000 or less.

[0036] The weight average molecular weight of the polymer A having the structural unit represented by the formula (1) can be measured and calculated by the following method.

[0037] (Weight average molecular weight measured by GPC) The weight average molecular weight according to the present disclosure is measured by gel permeation chromatography (GPC) as follows. First, the sample is dissolved in tetrahydrofuran (THF) at room temperature for 24 hours. The resulting solution is then filtered through a solvent-resistant membrane filter "Maesholidisc" (manufactured by Tosoh Corporation) with a pore size of 0.2 μm to obtain a sample solution. The sample solution is adjusted so that the concentration of components soluble in THF is approximately 0.8 mass%. This sample solution is used for measurements under the following conditions. Apparatus: HLC8120 GPC (detector: RI) (Tosoh Corporation) Column: Shodex KF-801, 802, 803, 804, 805, 806, 807 (7 columns, manufactured by Showa Denko Co., Ltd.) Eluent: tetrahydrofuran (THF) ·Flow rate: 1.0ml / min Oven temperature: 40.0℃ Sample injection volume: 0.10 ml To calculate the molecular weight of a sample, a molecular weight calibration curve prepared using standard polystyrene resins (e.g., trade names "TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500", manufactured by Tosoh Corporation) is used.

[0038] The content of the polymer A having the structural unit represented by the formula (1) in the surface layer relative to the fluorine-containing resin particles is preferably 2% by mass or more and 10% by mass or less from the viewpoints of improving dispersibility and suppressing potential fluctuations. Furthermore, the content of the polymer A having the structural unit represented by the formula (1) in the surface layer relative to the fluorine-containing resin particles is more preferably 4% by mass or more and 8% by mass or less from the viewpoints of improving dispersibility and suppressing potential fluctuations.

[0039] The polymer A is preferably a polymer having a structural unit represented by the formula (1) and a structural unit represented by the following formula (2). [ka] (In formula (2), Y A1 represents an unsubstituted alkylene group, Y B represents an unsubstituted alkylene group, an alkylene group substituted with a halogen atom, an alkylene group substituted with a hydroxy group, an ester bond (-COO-), an amide bond (-NHCO-), a urethane bond (-NHCOO-), or a divalent linking group derived by combining one or more of these groups or bonds with -O- or -S-, or a single bond; ZA represents a structure represented by formula (2A), a cyano group, or a phenyl group, R 21 , R 22 each independently represents a hydrogen atom or a methyl group, m is an integer between 25 and 150. [ka] (In formula (2A), Z A1 represents an alkyl group having 1 to 4 carbon atoms.

[0040] In formula (2), Y B When represents an ester bond, -Y A1 -Y B -CH2- is -Y A1 -CO-O-CH2- and -Y A1 -O-CO-CH2-, and preferably -Y A1 -CO-O-CH2-. In addition, in formula (2), Y B represents an amide bond, -Y A1 -Y B -CH2- is -Y A1 -NH-CO-CH2- and -Y A1 -CO-NH-CH2-, and preferably -Y A1 -NH-CO-CH2-. In addition, in formula (2), Y B If is a urethane bond, -Y A1 -Y B -CH2- is -Y A1 -NH-CO-O-CH2- and -Y A1 -O-CO-NH-CH2-, and preferably -Y A1 -NH-CO-O-CH2-.

[0041] In addition, -Y in the formula (2) A1 -Y B -Y A1 -(Y A2 ) b -(Y A3 ) c -(Y A4 ) d -(YA5 ) e -(Y A6 ) f It is preferred that the compound has a structure represented by the formula: (Y A1 represents an unsubstituted alkylene group, Y A2 represents a methylene group substituted with at least one atom selected from the group consisting of a hydroxy group and a halogen atom, Y A3 represents an unsubstituted alkylene group, Y A4 represents an ester bond, an amide bond, or a urethane bond, Y A5 represents an unsubstituted alkylene group, Y A6 represents an oxygen atom or a sulfur atom, b, c, d, e, and f each independently represent 0 or 1.

[0042] It is preferable that the polymer A has, as structural units, only the structural unit represented by the formula (1) and the structural unit represented by the formula (2).

[0043] In the formula (2), [ka] is preferably not an acidic group with a pKa of 3 or less.

[0044] In the formula (2), [ka] is preferably not —SO3H.

[0045] In polymer A having a structural unit represented by formula (1) and a structural unit represented by formula (2), the molar ratio of the structural unit represented by formula (1) to the structural unit represented by formula (2) is preferably 1:19 to 19:1, more preferably 1:1 to 19:1, and even more preferably 7:3 to 9:1.

[0046] Examples of the structural unit represented by the formula (2) include those having the structures shown in Table 2 below. [Table 2-1] [Table 2-2]

[0047] <Electrophotographic photoreceptor> An example of the layer structure of an electrophotographic photoreceptor of the present disclosure is shown in Figure 1. In Figure 1, an undercoat layer 102, a charge generation layer 103, a charge transport layer 104, and a surface layer 105 are laminated on a support 101. The photosensitive layer may be a laminated photosensitive layer having a charge generation layer and a charge transport layer, or may be a single-layer photosensitive layer containing a charge generation material and a charge transport material.

[0048] The surface layer of the electrophotographic photoreceptor of the present disclosure contains fluorine atom-containing resin particles and polymer A having a structural unit represented by the above formula (1).

[0049] A method for producing the electrophotographic photoreceptor of the present disclosure includes preparing a coating liquid for each layer described below, coating the desired layers in order, and drying the coating liquid. Examples of methods for applying the coating liquid include dip coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, and ring coating. Among these, dip coating is preferred from the viewpoints of efficiency and productivity.

[0050] The configuration of the electrophotographic photoreceptor of the present disclosure will be described below. <Support> The support of the electrophotographic photoreceptor is preferably conductive (conductive support). The support may be cylindrical, belt-like, or sheet-like. Of these, a cylindrical support is preferred. The surface of the support may be subjected to electrochemical treatment such as anodization, blasting, cutting, or the like. The support is preferably made of a metal, a resin, or a glass. Examples of metals include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. Among these, an aluminum support using aluminum is preferred. It is also preferable to impart electrical conductivity to the resin or glass by processing such as mixing or coating with an electrically conductive material.

[0051] <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 resin.

[0052] Examples of materials for the conductive particles include metal oxides, metals, and carbon black. Examples of metal oxides include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, strontium titanate, magnesium oxide, antimony oxide, bismuth oxide, etc. Examples of metals include aluminum, nickel, iron, nichrome, copper, zinc, silver, etc. Among these, it is preferable to use metal oxide particles as the conductive particles, and it is particularly preferable to use titanium oxide particles, tin oxide particles, or zinc oxide particles. When metal oxide particles are used as the conductive particles, 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 an element such as phosphorus or aluminum or an oxide thereof. The conductive particles may have a laminated structure including a core particle and a coating layer covering the core particle. Examples of the core particle include titanium oxide particles, barium sulfate particles, and zinc oxide particles. Examples of the coating layer include metal oxide particles such as tin oxide. When metal oxide particles are used as the conductive particles, the volume average particle size thereof is preferably 1 nm or more and 500 nm or less, and more preferably 3 nm or more and 400 nm or less.

[0053] Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, and alkyd resin. The conductive layer may further contain silicone oil, resin particles, a masking agent such as titanium oxide, and the like.

[0054] The conductive layer can be formed by preparing a coating solution for the conductive layer containing the above-mentioned materials and solvent, forming this coating film on a support, and drying it. Examples of solvents used in the coating solution for the conductive layer include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Examples of dispersion methods for dispersing the 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.

[0055] The thickness of the conductive layer is preferably 1 μm or more and 50 μm or less, and particularly preferably 3 μm or more and 40 μm or less.

[0056] <Undercoat layer> In the present disclosure, an undercoat layer may be provided on the support or the conductive layer. By providing an undercoat layer, adhesion between layers can be improved and a charge injection blocking function can be imparted.

[0057] The undercoat layer preferably contains a resin. Alternatively, the undercoat layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinylphenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, polyamide resin, polyamic acid resin, polyimide resin, polyamideimide resin, and cellulose resin. 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.

[0058] Furthermore, for the purpose of improving electrical properties, the undercoat layer may further contain an electron transport material, metal oxide particles, metal particles, a conductive polymer, etc. Among these, it is preferable to use an electron transport material or metal oxide particles. 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. Examples of metal oxide particles include particles of indium tin oxide, tin oxide, indium oxide, titanium oxide, strontium titanate, zinc oxide, and aluminum oxide. Silicon dioxide particles can also be used. Examples of metal particles include particles of gold, silver, and aluminum. The metal oxide particles contained in the undercoat layer may be surface-treated with a surface treatment agent such as a silane coupling agent.

[0059] The surface treatment of the metal oxide particles can be carried out by a common method, such as a dry method or a wet method. In the dry method, metal oxide particles are stirred in a mixer capable of high-speed stirring, such as a Henschel mixer, and an alcohol aqueous solution, organic solvent solution, or aqueous solution containing a surface treatment agent is added to the metal oxide particles to uniformly disperse them, followed by drying. In the wet method, metal oxide particles and a surface treatment agent are stirred in a solvent or dispersed in a sand mill using glass beads or the like, and after dispersion, the solvent is removed by filtration or vacuum distillation. After solvent removal, it is preferable to further bake the mixture at 100°C or higher.

[0060] The undercoat layer may further contain additives, such as known materials such as metal particles such as aluminum particles, conductive material particles such as carbon black, charge transport materials, metal chelate compounds, and organometallic compounds.

[0061] 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 on the support or the conductive layer, and drying and / or curing the coating film.

[0062] Examples of solvents used in the coating liquid for the undercoat layer include organic solvents such as alcohols, sulfoxides, ketones, ethers, esters, halogenated aliphatic hydrocarbons, aromatic compounds, etc. In the present disclosure, it is preferable to use alcohol-based and ketone-based solvents.

[0063] Dispersion methods for preparing the coating liquid for the undercoat layer include methods using a homogenizer, ultrasonic disperser, ball mill, sand mill, roll mill, vibration mill, attritor, and liquid collision type high-speed disperser.

[0064] The thickness of the undercoat layer is preferably 0.1 μm or more, more preferably 0.2 μm or more, and particularly preferably 0.3 μm or more, and is preferably 50 μm or less, more preferably 40 μm or less, more preferably 30 μm or less, more preferably 10 μm or less, and particularly preferably 5 μm or less.

[0065] <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) A multi-layer type photosensitive layer is a photosensitive layer having a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. (2) A single-layer type photosensitive layer is a photosensitive layer containing both a charge generation material and a charge transport material.

[0066] (1) Laminated photosensitive layer The laminated photosensitive layer has a charge generating layer and a charge transport layer.

[0067] (1-1) Charge generation layer The charge generating layer preferably contains a charge generating material and a resin.

[0068] 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.

[0069] Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl butyral resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinyl alcohol resin, cellulose resin, polystyrene resin, polyvinyl acetate resin, polyvinyl chloride resin, etc. Among these, polyvinyl butyral resin is more preferred.

[0070] 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.

[0071] 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 this coating film on the undercoat layer, and drying it. 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.

[0072] The thickness of the charge generating layer is preferably 0.1 μm or more and 1 μm or less, and more preferably 0.15 μm or more and 0.4 μm or less.

[0073] (1-2) Charge transport layer The charge transport layer preferably contains a charge transport material and a binder material. When a protective layer (described later) is not provided, the charge transport layer serves as the surface layer of the electrophotographic photoreceptor. In this case, the charge transport layer contains fluorine atom-containing resin particles, a binder material, and a polymer A having a structural unit represented by the formula (1).

[0074] Examples of the charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, triarylamine compounds, and resins having groups derived from these materials. Among these, triarylamine compounds are preferred. The content of the charge transport material in the charge transport layer is preferably 25% by mass to 70% by mass, and more preferably 30% by mass to 55% by mass, based on the total mass of the charge transport layer.

[0075] As the binding material, a thermoplastic resin (hereinafter also referred to as "resin") is used. Examples of thermoplastic 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 resin is preferably 4:10 to 20:10, and more preferably 5:10 to 12:10.

[0076] The content of the fluorine atom-containing resin particles in the charge transport layer is preferably 5% by weight to 15% by weight, and more preferably 7% by weight to 10% by weight.

[0077] The charge transport layer may also contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, etc. Specific examples of such additives include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, polystyrene resin particles, polyethylene resin particles, and boron nitride particles.

[0078] 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 this coating film on the charge generation layer, and drying it. Examples of solvents 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.

[0079] The 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.

[0080] (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 resin, and a solvent, forming the coating on the undercoat layer, and drying the coating. The charge generating material, charge transport material, and resin are the same as those exemplified in "(1) Multilayer Photosensitive Layer" above.

[0081] <Protective layer> In the present disclosure, a protective layer may be provided on the photosensitive layer, which can improve durability.

[0082] When a protective layer is provided, the protective layer serves as the surface layer of the electrophotographic photoreceptor. In this case, the protective layer contains fluorine atom-containing resin particles, a binder material, and a polymer A having a structural unit represented by the formula (1).

[0083] The protective layer may be formed as a cured film by polymerizing a composition containing, for example, a monomer having a polymerizable functional group, which is a raw material for the binder material. Examples of the reaction include thermal polymerization, photopolymerization, and radiation polymerization. Examples of the polymerizable functional group possessed by the monomer having the polymerizable functional group include an isocyanate group, a blocked isocyanate group, a methylol group, an alkylmethylol group, an epoxy group, a metal alkoxyl group, a hydroxyl group, an amino group, a carboxyl group, a thiol group, a carboxylic acid anhydride group, and a group containing a carbon-carbon double bond. Examples of the group containing a carbon-carbon double bond include an acryloyl group and a methacryloyl group. A monomer having charge transport capability may be used as the monomer having the polymerizable functional group.

[0084] Here, the cured product of the monomer having a polymerizable functional group is the binder material of the protective layer. As the monomer having a polymerizable functional group, it is preferable to use a hole transporting compound having a chain-polymerizable functional group.

[0085] The hole transporting compound having a chain-polymerizable functional group is more preferably a compound represented by the following formula (CT-1) or (CT-2). [ka] (In the formula (CT-1), Ar 11 ~Ar 13 are each independently a substituted aryl group or an unsubstituted aryl group. The substituent that the substituted aryl group may have is an alkyl group having 1 to 6 carbon atoms, or a monovalent functional group represented by any one of the following formulas (P-1) to (P-3). However, the compound represented by the formula (CT-1) has at least one monovalent functional group represented by any one of the following formulas (P-1) to (P-3). [ka] (In the formula (CT-2), Ar 21 ~Ar 24 are each independently a substituted aryl group or an unsubstituted aryl group, and Ar 25 is a substituted arylene group or an unsubstituted arylene group. The substituent that the substituted aryl group may have is an alkyl group having 1 to 6 carbon atoms, or a monovalent functional group represented by the following formulas (P-1) to (P-3). The substituent that the substituted arylene group may have is an alkyl group having 1 to 6 carbon atoms, or a monovalent functional group represented by the following formulas (P-1) to (P-3). However, the compound represented by formula (CT-2) has at least one monovalent functional group represented by any of the following formulas (P-1) to (P-3). [ka] (In the formula (P-1), Z 11 is a single bond or an alkylene group having 1 to 6 carbon atoms, and X 11 is a hydrogen atom or a methyl group.) [ka] (In the formula (P-2), Z 21 is a single bond or an alkylene group having 1 to 6 carbon atoms. [ka] (In the formula (P-3), Z 31 is a single bond or an alkylene group having 1 to 6 carbon atoms.

[0086] The content of the fluorine atom-containing resin particles in the protective layer is preferably 20% by mass or more and 40% by mass or less, and more preferably 25% by mass or more and 35% by mass or less.

[0087] The protective layer preferably contains a compound represented by the following formula (3): In addition, when preparing a coating liquid for the surface layer, the compound represented by the following formula (3) is preferably a liquid compound from the viewpoint of being used as a dispersion medium. [ka] In the formula (3), R 31 is an alkyl group or a fluoroalkyl group. 32 is a fluoroalkyl group. 31 is preferably a fluoroalkyl group.

[0088] Examples of the compound represented by formula (3) include methyl nonafluorobutyl ether, ethyl nonafluorobutyl ether, 1,1,1,2,3,4,4,5,5,5-decafluoro-3-methoxy-2-(trifluoromethyl)pentane 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, etc. Among them, 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether is preferred from the viewpoints of improving dispersibility and suppressing potential fluctuations.

[0089] In terms of suppressing potential fluctuation, the content of the compound represented by formula (3) in the protective layer is preferably 1 ppm or more and 10 ppm or less.Moreover, it is more preferable that the compound represented by formula (3) is 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether.

[0090] The content of the compound represented by formula (3) in the protective layer can be measured, for example, by GCMS analysis. The surface layer on the electrophotographic photosensitive member is scraped off with a razor or the like to obtain a measurement sample, which serves as the film mass. The measurement sample is analyzed by GCMS to measure the content of the compound represented by formula (3) contained in the surface layer. The GCMS analysis can be performed using, for example, a GCMS-QP2000 (manufactured by Shimadzu Corporation). In the examples of the present disclosure, the measurement sample was obtained by the above-described method, and then the content of the compound represented by formula (3) was measured using the above-described GCMS device.

[0091] The protective layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, etc. Specific examples of such additives include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, and silicone oils.

[0092] The protective layer can be formed by preparing a coating solution for the protective layer containing the above-mentioned materials and solvent, forming the coating film on the photosensitive layer, and drying and / or curing it. 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.

[0093] The thickness of the protective layer is preferably 0.5 μm or more and 10 μm or less, and more preferably 1 μm or more and 7 μm or less.

[0094] <Surface treatment of electrophotographic photoreceptors> In the present disclosure, the surface of the electrophotographic photosensitive member may be subjected to a surface treatment. By performing the surface treatment, the behavior of a cleaning means (cleaning blade) that comes into contact with the electrophotographic photosensitive member can be further stabilized. Examples of surface treatment methods include a method in which a mold having convex portions is pressed against the surface of the electrophotographic photosensitive member to transfer the shape, a method in which an uneven shape is imparted by mechanical polishing, or a method in which powder is collided with the surface of the electrophotographic photosensitive member to roughen the surface. In this way, by providing concave or convex portions on the surface layer of the electrophotographic photosensitive member, the behavior of a cleaning means that comes into contact with the electrophotographic photosensitive member can be further stabilized.

[0095] The recesses or protrusions may be formed over the entire surface of the electrophotographic photosensitive member, or may be formed on only a part of the surface of the electrophotographic photosensitive member. When the recesses or protrusions are formed on only a part of the surface of the electrophotographic photosensitive member, it is preferable that the recesses or protrusions are formed over at least the entire contact area with the cleaning means (cleaning blade).

[0096] When forming recesses, a mold having protrusions corresponding to the recesses is pressed against the surface of the electrophotographic photosensitive member to transfer the shape, thereby forming the recesses on the surface of the electrophotographic photosensitive member.

[0097] <Abrasive tools used for mechanical polishing> Mechanical polishing can be performed by known means. Generally, an abrasive tool is brought into contact with an electrophotographic photosensitive member, and one or both of them are moved relatively to polish the surface of the electrophotographic photosensitive member. The abrasive tool is a polishing member having a substrate and a layer in which abrasive grains are dispersed in a binder resin.

[0098] Examples of abrasive grains include particles of aluminum oxide, chromium oxide, diamond, iron oxide, cerium oxide, corundum, silica stone, silicon nitride, boron nitride, molybdenum carbide, silicon carbide, tungsten carbide, titanium carbide, and silicon oxide. The particle size of the abrasive grains is preferably 0.01 to 50 μm, and more preferably 1 to 15 μm. If the particle size of the abrasive grains is too small, the polishing power becomes weak, making it difficult to increase the F / C ratio of the outermost surface of the electrophotographic photosensitive member. These abrasive grains can be used alone or in combination of two or more types. When two or more types are mixed, the materials and particle sizes may be different or the same.

[0099] The binder resin used to disperse the abrasive grains in the polishing tool can be any of the well-known thermoplastic resins, thermosetting resins, reactive resins, electron beam curable resins, ultraviolet curable resins, visible light curable resins, and antifungal resins. Examples of thermoplastic resins include vinyl chloride resins, polyamide resins, polyester resins, polycarbonate resins, amino resins, styrene-butadiene copolymers, urethane elastomers, and polyamide-silicone resins. Examples of thermosetting resins include phenolic resins, phenoxy resins, epoxy resins, polyurethane resins, polyester resins, silicone resins, melamine resins, and alkyd resins. An isocyanate-based curing agent may also be added to the thermoplastic resin.

[0100] The thickness of the layer of the abrasive tool, in which abrasive grains are dispersed in a binder resin, is preferably 1 to 100 μm. If the layer is too thick, unevenness in the layer thickness is likely to occur, resulting in unevenness in the surface roughness of the object to be polished. On the other hand, if the layer is too thin, abrasive grains are likely to fall off.

[0101] The shape of the substrate of the abrasive tool is not particularly limited. In the examples of the present disclosure, a sheet-like substrate is used to efficiently abrade a cylindrical electrophotographic photoreceptor, but other shapes may also be used. (Hereinafter, the abrasive tool of the present disclosure will also be referred to as an abrasive sheet.) The material of the substrate of the abrasive tool is also not particularly limited. For example, the material of the sheet-like substrate may be paper, woven fabric, nonwoven fabric, or plastic film.

[0102] The abrasive tool can be obtained by coating a base material with a coating material in which the above-mentioned abrasive grains, binder resin, and a solvent capable of dissolving the binder resin are mixed and dispersed, and then drying the coating material.

[0103] <Polishing equipment> An example of the polishing device for the electrophotographic photosensitive member of the present disclosure is shown in FIG. FIG. 2 shows an apparatus for polishing a cylindrical electrophotographic photoreceptor using an abrasive sheet. In FIG. 2, the abrasive sheet 2-1 is wound around a hollow shaft 2-6, and a motor (not shown) is arranged to apply tension to the abrasive sheet 2-1 in the direction opposite to the direction in which the abrasive sheet 2-1 is fed around the shaft 2-6. The abrasive sheet 2-1 is fed in the direction indicated by the arrow, passing through guide rollers 2-2a and 2-2b and a backup roller 2-3. After polishing, the abrasive sheet 2-1 is wound around a winding means 2-5 by a motor (not shown) via guide rollers 2-2c and 2-2d. Polishing is performed by constantly pressing the abrasive sheet 2-1 against the workpiece (electrophotographic photoreceptor before polishing) 2-4. Because the abrasive sheet 2-1 is often insulating, it is preferable to use a grounded or conductive material for the area in contact with the abrasive sheet 2-1.

[0104] The feed speed of the abrasive sheet 2-1 is preferably in the range of 10 to 1000 mm / min. If the feed rate is too low, the binder resin may adhere to the surface of the abrasive sheet 2-1, which may cause deep scratches on the surface of the object 2-4 to be treated.

[0105] The workpiece 2-4 is placed opposite the backup roller 2-3 via the abrasive sheet 2-1. The backup roller 2-3 is preferably an elastic body from the viewpoint of improving the uniformity of the surface roughness of the workpiece 2-4. At this time, the workpiece 2-4 and the backup roller 2-3 are pressed against each other via the abrasive sheet 2-1 at a desired setting value for a predetermined time, and the surface of the workpiece 2-4 is polished. The rotation direction of the workpiece 2-4 may be the same as or opposite to the feeding direction of the abrasive sheet 2-1. Furthermore, the rotation direction may be changed during polishing.

[0106] The pressing pressure of the backup roller 2-3 against the object to be processed 2-4 is preferably 0.005 to 15 N / m, although it depends on the hardness and polishing time of the backup roller 2-3. 2 It is preferred.

[0107] The surface roughness of the electrophotographic photoreceptor can be adjusted by appropriately selecting the feed speed of the polishing sheet 2-1, the pressing pressure of the backup roller 2-3, the abrasive grain type of the polishing sheet, the film thickness of the binder resin of the polishing sheet, the thickness of the substrate, and the like.

[0108] <Measurement of the maximum height Rmax in JIS B0601 1982> The surface roughness of the electrophotographic photoreceptor can be measured by known means. For example, the following can be mentioned. A surface roughness meter such as the Surfcoader SE3500 type surface roughness measuring instrument manufactured by Kosaka Laboratory Ltd. A non-contact three-dimensional surface measuring machine Micro Map 557N manufactured by Hishikawa System Co., Ltd. A microscope capable of acquiring three-dimensional shapes such as the ultra-depth shape measuring microscope VK-8550 and VK-9000 manufactured by Keyence Corporation.

[0109] In the present disclosure, among the indexes of surface roughness, the maximum height Rmax in JIS B0601 1982 defined by the Japanese Industrial Standard JIS is used as the polishing depth L (μm). Further, in the present disclosure, the Rmax is measured in advance for the range of the 5 mm square section of the electrophotographic photoreceptor cut out as a specimen for the X-ray photoelectron spectroscopy described later. The measurement is performed arbitrarily at three locations in the range of 5 mm square, and the average value thereof is adopted as the polishing depth L (μm).

[0110] <Process cartridge, electrophotographic apparatus> The electrophotographic photosensitive member of the present disclosure may be one of the components of a process cartridge or an electrophotographic apparatus. The process cartridge is characterized by integrally supporting the electrophotographic photosensitive member described above and at least one means selected from the group consisting of a charging means, a developing means, a transfer means, and a cleaning means, and is detachably mountable to the main body of the electrophotographic apparatus. The electrophotographic apparatus is characterized by having the electrophotographic photosensitive member described above, a charging means, an exposure means, a developing means, and a transfer means.

[0111] FIG. 3 shows an example of a schematic configuration of an electrophotographic apparatus having a process cartridge equipped with an electrophotographic photosensitive member.

[0112] A cylindrical (drum-shaped) electrophotographic photoreceptor 201 is rotated around an axis 202 in the direction of the arrow at a predetermined peripheral speed (process speed). During rotation, the surface of the electrophotographic photoreceptor 201 is charged to a predetermined positive or negative potential by a charging unit 203. While FIG. 3 shows a roller charging method using a roller-type charging member, other charging methods, such as corona charging, proximity charging, and injection charging, may also be used. Exposure light 204 from an exposure unit (not shown) is irradiated onto the charged surface of the electrophotographic photoreceptor 201, forming an electrostatic latent image corresponding to the target image information. The exposure light 204 is intensity-modulated in response to a time-series electric digital image signal of the target image information, and is output from an image exposure unit such as a slit exposure unit or laser beam scanning exposure unit. The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 201 is developed (normal development or reversal development) with toner contained in a developing unit 205, forming a toner image on the surface of the electrophotographic photoreceptor 201. The toner image formed on the surface of the electrophotographic photosensitive member 201 is transferred to a transfer material 207 by transfer means 206. At this time, a bias voltage of a polarity opposite to that of the charge carried by the toner is applied to the transfer means 206 from a bias power supply (not shown). When the transfer material 207 is paper, the transfer material 207 is taken out from a paper feed unit (not shown) and fed between the electrophotographic photosensitive member 201 and transfer means 206 in synchronization with the rotation of the electrophotographic photosensitive member 201. The transfer material 207 onto which the toner image has been transferred from the electrophotographic photosensitive member 201 is separated from the surface of the electrophotographic photosensitive member 201 and transported to fixing means 208, where the toner image is fixed, and the transferred material is printed out of the electrophotographic apparatus as an image-formed product (print, copy). The electrophotographic apparatus may also have cleaning means 209 for removing deposits such as toner remaining on the surface of the electrophotographic photosensitive member 201 after transfer. Alternatively, a so-called cleanerless system may be used in which the deposits are removed by the developing means or the like without providing a separate cleaning means. A process cartridge can be formed by housing a plurality of components selected from the electrophotographic photosensitive member 201, the charging means 203, the developing means 205, and the cleaning means 209 in a container and supporting them integrally. In addition, the process cartridge can be configured to be detachable from the main body of the electrophotographic apparatus.For example, it may be configured as follows: At least one selected from a charging unit 203, a developing unit 205, and a cleaning unit 209 is integrally supported together with an electrophotographic photosensitive member 201 to form a cartridge. This can be made into a process cartridge 211 that can be attached to and detached from the main body of the electrophotographic apparatus using guide units 212 such as rails of the main body of the electrophotographic apparatus. The electrophotographic apparatus may have a charge-removing mechanism that removes charge from the surface of the electrophotographic photosensitive member 201 with pre-exposure light 210 from a pre-exposure unit (not shown). Furthermore, guide units 212 such as rails may be provided to attach and detach the process cartridge 11 to and from the main body of the electrophotographic apparatus. The electrophotographic apparatus of the present disclosure is characterized by having an electrophotographic photosensitive member 201, as well as a charging unit 203, an exposure unit, a developing unit 205, and a transfer unit 206.

[0113] FIG. 4 shows the configuration of a process cartridge equipped with the electrophotographic photosensitive member of the present disclosure, and FIG. 5 shows an example of the schematic configuration of an electrophotographic apparatus having the process cartridge of FIG.

[0114] In Figure 4, a cylindrical electrophotographic photosensitive member 1 is rotated in the direction of the arrow at a predetermined peripheral speed. The peripheral surface of the rotationally driven electrophotographic photosensitive member 1 is uniformly charged to a predetermined positive or negative potential by charging means 2. Next, the charged peripheral surface of the electrophotographic photosensitive member 1 is exposed to exposure light (image exposure light) 3 output from exposure means (not shown) such as slit exposure or laser beam scanning exposure. In this way, an electrostatic latent image corresponding to a target image is sequentially formed on the peripheral surface of the electrophotographic photosensitive member 1. The voltage applied to the charging means (such as a charging roller) 2 may be a voltage in which an AC component is superimposed on a DC component, or a voltage consisting of only a DC component.

[0115] The electrostatic latent image formed on the peripheral surface of the electrophotographic photosensitive member 1 is developed into a toner image by the toner contained in the developer of the developing means 4. Next, the toner image formed and carried on the peripheral surface of the electrophotographic photosensitive member 1 is sequentially transferred onto a transfer material (paper, intermediate transfer member, etc.) 6 by a transfer bias from a transfer means (transfer roller, etc.) 5. The transfer material 6 is fed in synchronization with the rotation of the electrophotographic photosensitive member 1.

[0116] After the toner image is transferred, the surface of the electrophotographic photoreceptor 1 is subjected to a charge removal process using pre-exposure light 7 from a pre-exposure means (not shown), and then the surface is cleaned by removing the residual toner from the surface by a cleaning means 8, and the electrophotographic photoreceptor 1 is then repeatedly used for image formation. The pre-exposure means may be placed before or after the cleaning step, and the pre-exposure means is not necessarily required.

[0117] The electrophotographic photosensitive member 1 may be mounted in an electrophotographic apparatus such as a copying machine or a laser beam printer. Alternatively, a process cartridge 9 configured by housing a plurality of components, such as the electrophotographic photosensitive member 1, charging means 2, developing means 4, and cleaning means 8, in a container and integrally supporting them may be configured to be detachably attachable to the main body of the electrophotographic apparatus. In FIG. 4, the electrophotographic photosensitive member 1, charging means 2, developing means 4, and cleaning means 8 are integrally supported to form a process cartridge 9 that is detachably attachable to the main body of the electrophotographic apparatus.

[0118] Next, an electrophotographic apparatus equipped with the electrophotographic photoreceptor of the present disclosure will be described. An example of the configuration of the electrophotographic apparatus of the present disclosure is shown in Figure 5. A yellow process cartridge 17, a magenta process cartridge 18, a cyan process cartridge 19, and a black process cartridge 20, each corresponding to a different color, are arranged side by side along the intermediate transfer body 10. The diameter, constituent materials, developer, charging method, and other means of the electrophotographic photosensitive member do not necessarily need to be the same for each color.

[0119] When the image formation operation begins, toner images of each color are sequentially superimposed on the intermediate transfer body 10 according to the image formation process described above. In parallel, transfer paper 11 is fed from paper feed tray 13 via paper feed path 12 and fed to secondary transfer means 14 in synchronization with the rotation of the intermediate transfer body. The toner image on the intermediate transfer body 10 is transferred to the transfer paper 11 by a transfer bias from secondary transfer means 14. The toner image transferred onto the transfer paper 11 is transported along paper feed path 12, fixed on the transfer paper by fixing means 15, and then discharged from paper discharge section 16.

[0120] The electrophotographic photoreceptor of the present disclosure can be used in laser beam printers, LED printers, copiers, facsimiles, and multifunction machines thereof. [Example]

[0121] The present disclosure will be described in more detail below using examples and comparative examples, but is not limited thereto. In the following description of the examples, "parts" are by mass unless otherwise specified.

[0122] <Synthesis of Polymer A Having Structural Unit Represented by Formula (1)> Polymer A (hereinafter also referred to as "graft copolymer") having a structural unit represented by formula (1) in the present disclosure was synthesized as follows. The acrylate compound and macromonomer compound used in the synthesis examples below can be produced by referring to, for example, JP 2009-104145 A.

[0123] (Graft copolymer 1) 50 parts of 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate (Sigma-Aldrich), 75 parts of a macromonomer (number average molecular weight 6,000) represented by the following formula (A), 0.437 parts of 1,1'-azobis(1-acetoxy-1-phenylethane) (trade name: OTAZO-15, Otsuka Chemical Co., Ltd.), and 338 parts of n-butyl acetate were mixed in a glass flask equipped with a stirrer, reflux condenser, nitrogen gas inlet tube, thermostatic bath, and thermometer at 20°C under a nitrogen atmosphere for 30 minutes, and then the reaction mixture was heated to 85-90°C and reacted for 5 hours. The reaction was stopped by cooling with ice, and a precipitate was obtained by adding 1500 parts of 2-propanol. This precipitate was washed with a mixed solvent of n-butyl acetate:2-propanol=1:5 and dried at a temperature of 80° C. under reduced pressure of 1325 Pa or less for 3 hours, thereby obtaining graft copolymer 1. [ka]

[0124] (Graft copolymer 2) Graft copolymer 2 was obtained in the same manner as for graft copolymer 1, except that 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate was changed to 1H,1H-perfluoro(2,5-dimethyl-4,6-dioxanonanoyl)acrylate.

[0125] (Graft copolymer 3) Graft copolymer 3 was obtained in the same manner as for graft copolymer 1, except that 40 parts of 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate was used instead of 1H,1H-perfluoro(4,7-dioxanonanoyl)acrylate.

[0126] (Graft copolymer 4) Graft copolymer 4 was obtained in the same manner as graft copolymer 1, except that 55 parts of 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate was used instead of 1H,1H-perfluoro(3,6-dimethyl-4,7-dioxadecanoyl)acrylate.

[0127] (Graft Copolymer 5) Graft copolymer 5 was obtained in the same manner as graft copolymer 1, except that the amounts of 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate and the macromonomer represented by formula (A) were changed to 2.5 parts and 570 parts, respectively.

[0128] (Graft Copolymer 6) Graft copolymer 6 was obtained in the same manner as graft copolymer 1, except that the amounts of 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate and the macromonomer represented by formula (A) were changed to 12.5 parts and 450 parts, respectively.

[0129] (Graft Copolymer 7) Graft copolymer 7 was obtained in the same manner as graft copolymer 1, except that the amounts of 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate and the macromonomer represented by formula (A) were changed to 25 parts and 300 parts, respectively.

[0130] (Graft Copolymer 8) Graft copolymer 8 was obtained in the same manner as graft copolymer 1, except that the amounts of 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate and the macromonomer represented by formula (A) were changed to 35 parts and 180 parts, respectively.

[0131] (Graft Copolymer 9) Graft Copolymer 9 was obtained in the same manner as for Graft Copolymer 1, except that 56.25 parts of 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate was used.

[0132] (Graft Copolymer 10) Graft copolymer 10 was obtained in the same manner as for graft copolymer 1, except that 0.819 parts of 1,1'-azobis(1-acetoxy-1-phenylethane) was used.

[0133] (Graft copolymer 11) Graft copolymer 11 was obtained in the same manner as for graft copolymer 1, except that 0.728 parts of 1,1'-azobis(1-acetoxy-1-phenylethane) was used.

[0134] (Graft copolymer 12) Graft copolymer 12 was obtained in the same manner as for graft copolymer 1, except that 0.164 parts of 1,1'-azobis(1-acetoxy-1-phenylethane) was used.

[0135] (Graft copolymer 13) Graft copolymer 13 was obtained in the same manner as for graft copolymer 1, except that 0.131 parts of 1,1'-azobis(1-acetoxy-1-phenylethane) was used.

[0136] (Graft copolymer 14) Graft copolymer 14 was obtained in the same manner as for graft copolymer 1, except that 0.874 parts of 1,1'-azobis(1-acetoxy-1-phenylethane) was used.

[0137] (Graft copolymer 15) Graft Copolymer 15 was obtained in the same manner as Graft Copolymer 1, except that 0.119 parts of 1,1'-azobis(1-acetoxy-1-phenylethane) was used.

[0138] (Graft copolymer 16) Graft copolymer 16 was obtained in the same manner as graft copolymer 1, except that the amounts of 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate and the macromonomer represented by formula (A) were changed to 20 parts and 360 parts, respectively.

[0139] (Graft copolymer 17) Graft copolymer 17 was obtained in the same manner as graft copolymer 1, except that 50 parts of 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate and 30 parts of the macromonomer represented by formula (A) were used.

[0140] (Graft copolymer 18) Graft copolymer 18 was obtained in the same manner as for graft copolymer 1, except that 25 parts of 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate was used instead of 1H,1H-perfluoro(3,5-dioxahexanoyl)acrylate.

[0141] (Graft copolymer 19) Graft copolymer 19 was obtained in the same manner as for graft copolymer 1, except that 35 parts of 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate was used instead of 1H,1H-perfluoro(3,6-dioxaoctanoyl)acrylate.

[0142] (Graft copolymer 20) Graft copolymer 20 was obtained in the same manner as for graft copolymer 1, except that 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate was changed to 1H,1H-perfluoro(4,7-dioxaundecanoyl)acrylate.

[0143] (Graft copolymer 21) Graft copolymer 21 was obtained in the same manner as graft copolymer 1, except that 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate was changed to 1H,1H,2H,2H-perfluoro(3,6-dimethyl-4,7-dioxadecanoyl)acrylate.

[0144] (Graft copolymer 22) Graft copolymer 22 was obtained in the same manner as graft copolymer 1, except that 1H,1H-perfluoro(2,5-dimethyl-3,6-dioxanonanoyl)acrylate was changed to 1H,1H,2H,2H-perfluoro(4,7-dioxaundecanoyl)acrylate.

[0145] The resulting graft copolymers 1 to 22 were subjected to GPC measurement by the method described above, and the weight average molecular weights were calculated. The results are shown in Table 3.

[0146] [Table 3]

[0147] <Production of Electrophotographic Photoreceptor> Example 1-1 (Support 1) A cylindrical aluminum cylinder (JIS-A3003, aluminum alloy, outer diameter 30.6 mm, length 370 mm, wall thickness 1 mm) was used as a support (conductive support). It was ultrasonically cleaned in a cleaning solution containing pure water and detergent (product name: Chemicol CT, manufactured by Tokiwa Chemical Co., Ltd.), and after the cleaning solution was rinsed off, it was further ultrasonically cleaned in pure water and degreased. This was designated Support 1.

[0148] (Undercoat layer 1) Zinc oxide particles (specific surface area: 19 m 2 / g, powder resistance: 4.7×10 6 100 parts of the sol-gel (Ω·cm) was mixed with 500 parts of toluene and stirred, to which 0.8 parts of a silane coupling agent (compound name: N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, product name: KBM602, manufactured by Shin-Etsu Chemical Co., Ltd.) was added and stirred for 6 hours. Thereafter, the toluene was distilled off under reduced pressure, and the particles were dried by heating at 130°C for 6 hours to obtain surface-treated zinc oxide particles A.

[0149] Next, 15 parts of butyral (trade name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) as a polyol and 15 parts of blocked isocyanate (trade name: Duranate TPA-B80E, nonvolatile content 80% by mass, manufactured by Asahi Kasei Chemicals Corp.) were dissolved in a mixed solvent of 73.5 parts of methyl ethyl ketone and 73.5 parts of 1-butanol. To this solution, 80.8 parts of surface-treated zinc oxide particles A and 0.81 parts of 2,3,4-trihydroxybenzophenone (manufactured by Tokyo Chemical Industry Co., Ltd.) were added, and the mixture was dispersed in a sand mill using glass beads with a diameter of 0.8 mm in an atmosphere of 23±3°C for 3 hours. After the dispersion process, 0.01 parts of silicone oil (trade name: SH28PA, manufactured by Toray Dow Corning Co., Ltd. (formerly Toray Dow Corning Silicones Co., Ltd.)) and 5.6 parts of cross-linked polymethyl methacrylate (PMMA) particles (trade name: Techpolymer SSX-103, manufactured by Sekisui Plastics Co., Ltd., average primary particle size: 3 μm) were added and stirred to prepare a coating solution for the undercoat layer. The obtained coating liquid for undercoat layer was dip-coated onto the support 1 to form a coating film, and the coating film was dried at 160° C. for 30 minutes to form an undercoat layer 1 with a film thickness of 18 μm.

[0150] (Charge generation layer 1) Four parts of hydroxygallium phthalocyanine crystals (charge generating material) with strong peaks at Bragg angles 2θ±0.2° (7.4° and 28.1°) in CuKα characteristic X-ray diffraction and 0.04 parts of a compound represented by the following formula (E) were added to a solution prepared by dissolving 2 parts of polyvinyl butyral (trade name: S-LEC BX-1, manufactured by Sekisui Chemical Co., Ltd.) in 100 parts of cyclohexanone. The mixture was then dispersed in a sand mill using 1 mm diameter glass beads in an atmosphere of 23±3°C for 1 hour, and after the dispersion process, 100 parts of ethyl acetate was added to prepare a coating solution for a charge generating layer. This charge generating layer coating liquid was dip coated onto the undercoat layer 1, and the resulting coating was dried at 90° C. for 10 minutes to form a charge generating layer 1 having a thickness of 0.15 μm. [ka]

[0151] (Charge transport layer 1) A coating solution for a charge transport layer was prepared by dissolving 60 parts of a compound represented by the following formula (F), 30 parts of a compound represented by the following formula (G), 10 parts of a compound represented by the following formula (H), 100 parts of a bisphenol Z-type polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Engineering-Plastics Corporation), and 0.2 parts of a polycarbonate having a unit represented by the following formula (I) (viscosity average molecular weight Mv: 20,000) in a mixed solvent of 272 parts of o-xylene, 256 parts of methyl benzoate, and 272 parts of dimethoxymethane. This charge transport layer coating liquid was dip coated onto the charge generation layer 1 to form a coating film, and the resulting coating film was dried at 115° C. for 50 minutes to form a charge transport layer 1 having a thickness of 18 μm. [ka] [ka] [ka] [ka] (In formula (I), 0.95 and 0.05 are the molar ratios (copolymerization ratios) of the two units.)

[0152] (protective layer) A dispersant solution was prepared by dissolving 2.20 parts of the above-mentioned graft copolymer 1 in a mixed solvent consisting of 100 parts of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether (trade name: AE-3000, manufactured by AGC Corporation) and 100 parts of 1-propanol. To the resulting dispersant solution, 40 parts of polytetrafluoroethylene resin particles (average primary particle size 210 nm, average circularity 0.85) were added, and the mixture was passed through a high-pressure disperser (product name: Microfluidizer M-110EH, manufactured by Microfluidics, Inc., USA) to obtain a polytetrafluoroethylene resin particle dispersion.

[0153] To the obtained polytetrafluoroethylene resin particle dispersion, 75.4 parts of a hole transport compound represented by the following formula (B), 21.9 parts of a compound represented by the following formula (C), and 100 parts of 1-propanol were added. Then, the mixture was filtered with a Polyflon filter (trade name: PF-040, manufactured by Advantec Toyo Co., Ltd.) to prepare a polytetrafluoroethylene resin particle dispersion (coating liquid for protective layer). [ka] [ka]

[0154] This protective layer coating solution was dip-coated onto the charge transport layer to form a coating film, and the resulting coating film was dried at 40°C for 5 minutes. After drying, the coating film was irradiated with an electron beam for 1.6 seconds under a nitrogen atmosphere at an acceleration voltage of 70 kV and an absorbed dose of 15 kGy. Then, under a nitrogen atmosphere, the coating film was heat-treated for 15 seconds to a temperature of 135°C. The oxygen concentration from the electron beam irradiation to the 15-second heat treatment was 15 ppm. Next, the coating film was naturally cooled in the atmosphere to a temperature of 25°C, and then heat-treated for 1 hour to a temperature of 105°C to form a surface layer (protective layer) with a thickness of 5 μm.

[0155] The content of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether in the surface layer was 5 ppm.

[0156] In this manner, an electrophotographic photoreceptor having a support and a surface layer before surface polishing was prepared.

[0157] <Surface treatment of electrophotographic photoreceptors> (Polishing of electrophotographic photoreceptor before surface polishing) The surface of the electrophotographic photosensitive member before the surface texture formation was polished using the polishing device shown in Figure 2 under the following conditions. Abrasive sheet feed speed: 400mm / min Electrophotographic photoreceptor rotation speed: 450 rpm Pressing of electrophotographic photoreceptor into backup roller: 3.5 mm Rotation direction of the abrasive sheet and electrophotographic photoreceptor; Backup roller; outer diameter 100 mm, Asker C hardness 25 The polishing sheet A to be attached to the polishing device was made by mixing the polishing grains used in GC3000 and GC2000 manufactured by Riken Corundum Co., Ltd. GC3000 (abrasive sheet surface roughness Ra0.83μm) GC2000 (abrasive sheet surface roughness Ra1.45μm) Polishing sheet A (polishing sheet surface roughness Ra1.12μm) The polishing time using the polishing sheet A was 20 seconds.

[0158] (Measurement of polishing depth L (μm)) The maximum height Rmax of the electrophotographic photosensitive member after polishing was measured in accordance with JIS B 0601 1982 using a surface roughness measuring instrument, Surfcorder SE3500, manufactured by Kosaka Laboratory Co., Ltd. The measurement conditions were set as follows. Measurement was carried out at three arbitrary locations within a 5 mm square area, and the average value was adopted as the polishing depth L (μm). The polishing depth L of the electrophotographic photosensitive member after surface polishing was 0.75 μm. In Examples 1-2 to 1-25 described later, the polishing depth L of the electrophotographic photosensitive member subjected to surface processing was all 0.75 μm. (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

[0159] [Examples 1-2 to 1-13, 1-22 to 1-27, Comparative Examples 1-1 to 1-3] An electrophotographic photoreceptor was produced in the same manner as in Example 1-1, except that in forming the protective layer, graft copolymer 1 was changed to the graft copolymer shown in Table 4. The content of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether in the surface layer is shown in Table 4.

[0160] Examples 1-14 to 1-15, 1-20 to 1-21 An electrophotographic photoreceptor was produced in the same manner as in Example 1-1, except that in forming the protective layer, the amount of graft copolymer 1 was changed to the part by mass shown in Table 4. The content of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether in the surface layer is shown in Table 4.

[0161] Examples 1-16 to 1-19 An electrophotographic photoreceptor was produced in the same manner as in Example 1-1, except that in forming the protective layer, polytetrafluoroethylene resin particles having the average primary particle size and average circularity shown in Table 4 were used. The content of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether in the surface layer is shown in Table 4.

[0162] [Table 4]

[0163] Example 2-1 (Support 2) A cylindrical aluminum cylinder (JIS-A3003, aluminum alloy, outer diameter 30 mm, length 357.5 mm, wall thickness 0.7 mm) was used as the support (conductive support). It was ultrasonically cleaned in a cleaning solution containing pure water and detergent (product name: Chemicol CT, manufactured by Tokiwa Chemical Co., Ltd.), and after the cleaning solution was rinsed off, it was further ultrasonically cleaned in pure water and degreased. This was designated support 2.

[0164] (Undercoat layer 2) Zinc oxide particles (average particle diameter: 70 nm, specific surface area: 15 m 2Sixty parts of zinc oxide particles (60 parts by weight / g) were mixed with 500 parts of tetrahydrofuran by stirring, and 0.75 parts of a silane coupling agent (compound name: N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, product name: KBM603, manufactured by Shin-Etsu Chemical Co., Ltd.) was added thereto and stirred for 2 hours. Thereafter, the tetrahydrofuran was distilled off under reduced pressure, and the mixture was dried by heating at 120°C for 3 hours to obtain surface-treated zinc oxide particles.

[0165] Next, 25 parts of butyral (trade name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) as a polyol and 22.5 parts of blocked isocyanate (trade name: Sumidur BL-3173, manufactured by Sumitomo Bayer Urethane Co., Ltd.) were dissolved in 142 parts of methyl ethyl ketone. To this solution, 100 parts of the surface-treated zinc oxide particles and 1 part of alizarin were added, and the mixture was dispersed for 5 hours in a sand mill using glass beads with a diameter of 1 mm. After the dispersion treatment, 0.008 parts of dioctyltin dilaurate and 6.5 parts of silicone resin particles (Tospearl 145, manufactured by GE Toshiba Silicones) were added and stirred to prepare a coating liquid for an undercoat layer. The obtained coating liquid for undercoat layer was dip-coated onto the support 2 to form a coating film, and the coating film was dried at 190° C. for 24 minutes to form an undercoat layer 2 with a thickness of 15 μm.

[0166] (Charge generation layer 2) Next, 15 parts of chlorogallium phthalocyanine crystals having strong diffraction peaks at Bragg angles (2θ±0.2°) of at least 7.4°, 16.6°, 25.5°, and 28.3° for CuKα characteristic X-rays, 10 parts of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nippon Union Carbide Co., Ltd.), and 300 parts of n-butyl alcohol were mixed and dispersed for 4 hours in a sand mill using 1 mm diameter glass beads to prepare a coating solution for the charge generating layer. This charge generating layer coating liquid was dip coated onto the undercoat layer 2, and the resulting coating was dried at 150° C. for 5 minutes to form a charge generating layer 2 having a thickness of 0.2 μm.

[0167] (charge transport layer) Next, 10 parts of polytetrafluoroethylene resin particles (average primary particle size 210 nm, average circularity 0.85), 0.50 parts of the above-mentioned graft copolymer 1, and 24 parts of tetrahydrofuran were mixed and stirred for 48 hours while maintaining the liquid temperature at 20°C to obtain Preparation A. Next, 53.2 parts of N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine, 14.1 parts of bisphenol Z-type polycarbonate resin (viscosity average molecular weight 40,000), and 0.26 parts of 2,6-di-t-butyl-4-methylphenol as an antioxidant were mixed, and 250 parts of tetrahydrofuran was added and dissolved to obtain Preparation B. Preparation A was added to Preparation B and mixed with stirring, and then passed through a high-pressure disperser (trade name: Microfluidizer M-110EH, manufactured by Microfluidics, Inc., USA) to obtain a dispersion.

[0168] Thereafter, fluorine-modified silicone oil (product name: FL-100, manufactured by Shin-Etsu Silicones Co., Ltd.) was added to the dispersion to a concentration of 5 ppm, and the dispersion was filtered using a Polyflon filter (product name: PF-040, manufactured by Advantech Toyo Co., Ltd.) to prepare a coating liquid for the charge transport layer. This charge transport layer coating liquid was dip coated onto the charge generating layer 2 to form a coating film, and the resulting coating film was dried at 150° C. for 25 minutes to form a charge transport layer with a thickness of 30 μm. In this way, an electrophotographic photoreceptor was prepared.

[0169] [Examples 2-2 to 2-13, 2-22 to 2-27, Comparative Examples 2-1 to 2-3] An electrophotographic photoreceptor was produced in the same manner as in Example 2-1, except that the graft copolymer 1 was changed to the graft copolymer shown in Table 5 in forming the charge transport layer.

[0170] [Examples 2-14 to 2-15, 2-20 to 2-21] An electrophotographic photoreceptor was produced in the same manner as in Example 2-1, except that the amount of graft copolymer 1 was changed to the parts by mass shown in Table 5 in forming the charge transport layer.

[0171] Examples 2-16 to 2-19 An electrophotographic photoreceptor was prepared in the same manner as in Example 2-1, except that in forming the charge transport layer, the polytetrafluoroethylene resin particles were changed to polytetrafluoroethylene resin particles having the average primary particle size and average circularity shown in Table 5.

[0172] [Table 5]

[0173] <Evaluation of Electrophotographic Photoreceptors> The electrophotographic photoreceptors obtained in Examples 1-1 to 1-27, 2-1 to 2-27, and Comparative Examples 1-1 to 1-3, 2-1 to 2-3 were evaluated as follows.

[0174] [Evaluation device 1-1] The electrophotographic photoreceptors prepared in Examples 1-1 to 1-27 and Comparative Examples 1-1 to 1-3 were installed in a copying machine, imagePRESS C800 (product name), manufactured by Canon Inc., and evaluated. Specifically, the evaluation device was placed in an environment of 23°C temperature and 50% RH relative humidity, and the prepared electrophotographic photosensitive member was attached to a magenta process cartridge, which was then attached to the station of the magenta process cartridge, and evaluation was performed.

[0175] [Evaluation device 1-2] The electrophotographic photoreceptors prepared in Examples 1-1 to 1-27 and Comparative Examples 1-1 to 1-3 were installed in a modified copy machine, imagePRESS C800 (product name), manufactured by Canon Inc. The charging means of the modified machine was a charging means of a type that applies a voltage in which an AC voltage is superimposed on a DC voltage to a roller-type contact charging member (charging roller), and the exposure means was an exposure means of a laser image exposure type (wavelength 680 nm). Specifically, the evaluation device was placed in an environment of 23°C temperature and 50% RH relative humidity, and the prepared electrophotographic photosensitive member was attached to a magenta process cartridge, which was then attached to the station of the magenta process cartridge, and evaluation was performed. The charging conditions were adjusted so that the charging potential was −800V and the exposure potential was −300V, and the charging potential and the exposure amount of the exposure means were adjusted.

[0176] The surface potential of the electrophotographic photosensitive member was measured by removing the developing cartridge from the evaluation device and inserting a potential measuring device therein. The potential measuring device was configured by disposing a potential measuring probe (trade name: model 6000B-8, manufactured by Trek Japan Co., Ltd.) at the development position of the developing cartridge. The position of the potential measuring probe relative to the electrophotographic photosensitive member was the center of the electrophotographic photosensitive member in the generatrix direction, with a gap of 3 mm from the surface of the electrophotographic photosensitive member. Furthermore, the potential at the center of the electrophotographic photosensitive member was measured using a surface potentiometer (trade name: model 344, manufactured by Trek Japan Co., Ltd.).

[0177] [Evaluation device 2-1] The electrophotographic photoreceptors prepared in Examples 2-1 to 2-27 and Comparative Examples 2-1 to 2-3 were installed in a copying machine imageRUNNER iR-ADV C5051 manufactured by Canon Inc. and evaluated. Specifically, the evaluation device was placed in an environment of 23°C temperature and 50% RH relative humidity, and the prepared electrophotographic photosensitive member was attached to a cyan color process cartridge, which was then attached to the station of the cyan process cartridge, and evaluation was performed.

[0178] [Evaluation device 2-2] The electrophotographic photoreceptors prepared in Examples 2-1 to 2-27 and Comparative Examples 2-1 to 2-3 were mounted on a modified copy machine, imageRUNNER iR-ADV C5051, manufactured by Canon Inc. (the charging means was a system in which a voltage in which an AC voltage was superimposed on a DC voltage was applied to a roller-type contact charging member (charging roller), and the exposure means was a laser image exposure system (wavelength 780 nm)), and evaluations were carried out. Specifically, the evaluation device was placed in an environment of 23°C temperature and 50% RH relative humidity, and the prepared electrophotographic photosensitive member was attached to a cyan color process cartridge, which was then attached to the station of the cyan process cartridge, and evaluation was performed. The charging conditions were adjusted so that the charging potential was −700V and the exposure potential was −200V, and the charging potential and the exposure amount of the exposure means were adjusted. The surface potential of the electrophotographic photosensitive member was measured by removing the developing cartridge from the evaluation device and inserting a potential measuring device therein. The potential measuring device was configured by placing a potential measuring probe (trade name: model 6000B-8, manufactured by Trek Japan Co., Ltd.) at the development position of the developing cartridge, and the position of the potential measuring probe relative to the electrophotographic photosensitive member was the center in the generating line direction of the electrophotographic photosensitive member, with a gap of 3 mm from the surface of the electrophotographic photosensitive member. Furthermore, the potential at the center of the electrophotographic photosensitive member was measured using a surface potentiometer (trade name: model 344, manufactured by Trek Japan Co., Ltd.).

[0179] (Initial image evaluation) Image evaluation was performed using the evaluation device 1-1 and evaluation device 2-1 described above. A solid white image was printed on A4-size gloss paper, and the number of image defects due to poor dispersion, i.e., black dots, contained in the area of ​​one circumference of the electrophotographic photoreceptor in the output image was visually evaluated according to the following evaluation ranks. The area of ​​one circumference of the electrophotographic photoreceptor is a rectangular region with a length of 297 mm, the long side length of A4 paper, and a width of 94.2 mm, the circumference of the electrophotographic photoreceptor. In this disclosure, ranks A, B, C, and D represent levels at which the effects of the present disclosure are achieved, with rank A being considered to be an excellent level. Rank E, on the other hand, was considered to be a level at which the effects of the present disclosure are not achieved. A: No black spots at all B: 1 to 3 black dots less than 1.5 mm in diameter, and no black dots 1.5 mm or more in diameter C: 1 to 3 black dots with a diameter of less than 1.5 mm, and 1 to 2 black dots with a diameter of 1.5 mm or more D: 4 to 5 black dots less than 1.5 mm in diameter, and 2 or less black dots 1.5 mm or more in diameter E: 6 or more black spots less than 1.5 mm in diameter, or 3 or more black spots 1.5 mm or more in diameter The results of the evaluation are shown in Table 6.

[0180] (Evaluation of potential fluctuations during repeated use) The potential fluctuation evaluation during repeated use was performed using the above-mentioned evaluation device 1-2 and evaluation device 2-2. A cartridge equipped with an electrophotographic photoreceptor was attached to the evaluation device, and the photoreceptor was repeatedly used by passing 10,000 sheets of paper. At the station where the electrophotographic photoreceptor was installed, 10,000 sheets of A4-sized plain paper were repeatedly imaged with a monochrome text image at a 1% print rate. The initial dark potential at this time was compared with the dark potential after 10,000 sheets of repeated image formation, and this was taken as the potential fluctuation value (ΔVd). The initial light potential was also compared with the light potential after 10,000 sheets of repeated image formation, and this was taken as the potential fluctuation value (ΔVl). After passing 10,000 sheets of paper, the cartridge was left for 5 minutes, and the developing cartridge was replaced with a potential measuring device. The light potential (Vlb) and dark potential (Vdb) after repeated use were measured. The difference between the dark potential after repeated use and the initial dark potential (Vda) was defined as the dark potential fluctuation (ΔVd = |Vdb| - |Vda|). The difference between the light potential after repeated use and the initial light potential (Vla) was defined as the light potential fluctuation (ΔVl = |Vlb| - |Vla|). In the evaluation using evaluation device 1-2, the light potential fluctuation was measured after repeated use of 100,000 sheets, 300,000 sheets, and 500,000 sheets. In the evaluation using evaluation device 2-2, the light potential fluctuation was measured after repeated use of 100,000 sheets. In the present disclosure, when the change in bright area potential is within 40 V, it is determined that the effect of the present disclosure is achieved, and among these, when the change in bright area potential is within 15 V, it is determined that it is a particularly excellent level. The results of the evaluation are shown in Table 6.

[0181] [Table 6] [Explanation of symbols]

[0182] 101 Support 102 Undercoat layer 103 Charge generation layer 104 Charge transport layer 105 Surface layer (protective layer) 201 Electrophotographic photoreceptor 202 axes 203 Charging means 204 Exposure light 205 Developing means 206 Transcription means 207 Transfer material 208 Fixing means 209 Cleaning means 210 Pre-exposure light 211 Process cartridge 212 Guidance means 1. Electrophotographic photoreceptor 2. Charging means 3 Exposure light (image exposure light) 4. Developing methods 5 Transfer Method 6 Transfer material 7 Pre-exposure light 8 Cleaning Method 9 Process cartridge 10 Intermediate transfer body 11 Transfer paper 12 Paper feed path 13 Paper tray 14 Secondary transfer means 15 Fixing Method 16 Paper output section 17 Yellow process cartridge 18 Magenta process cartridge 19 Cyan process cartridge 20 Black process cartridge

Claims

1. An electrophotographic photoreceptor having a surface layer, The surface layer is fluorine atom-containing resin particles; A binding material; A polymer A having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), Contains the polymer A does not have a structural unit having an acidic group having a pKa of 3 or less; An electrophotographic photoreceptor characterized by: 【Chemistry 1】 (In formula (1), R １１ represents a hydrogen atom or a methyl group, R １２ represents a single bond or a methylene group, Rf １ and Rf ２ each independently represents a perfluoroalkylene group having 1 to 3 carbon atoms or a perfluoroalkylidene group having 1 to 3 carbon atoms, Rf ３ represents a perfluoroalkyl group having 1 to 3 carbon atoms. 【Chemistry 2】 (In formula (2), Y A1 represents an unsubstituted alkylene group; Y B represents an unsubstituted alkylene group, an alkylene group substituted with a halogen atom, an alkylene group substituted with a hydroxy group, an ester bond (—COO—), an amide bond (—NHCO—), a urethane bond (—NHCOO—), or a divalent linking group derived by combining one or more selected from these groups and bonds with —O— or —S—, or a single bond; Z A represents a structure represented by the following formula (2A), a cyano group, or a phenyl group: R 21 and R 22 each independently represent a hydrogen atom or a methyl group; m is an integer of 25 or more and 150 or less. 【Transformation 3】 (In formula (2A), Z A1 represents an alkyl group having 1 to 4 carbon atoms.)

2. An electrophotographic photoreceptor having a surface layer, The surface layer is fluorine atom-containing resin particles; A binding material; A polymer A having a structural unit represented by the following formula (1), Contains the content of the polymer A is 2% by mass or more and 10% by mass or less relative to the mass of the fluorine atom-containing resin particles in the surface layer, the polymer A does not have a structural unit having an acidic group having a pKa of 3 or less; An electrophotographic photoreceptor characterized by: 【Chemistry 4】 (In formula (1), R 11 represents a hydrogen atom or a methyl group; R 12 represents a single bond or a methylene group; Rf 1 and Rf 2 each independently represent a perfluoroalkylene group having 1 to 3 carbon atoms or a perfluoroalkylidene group having 1 to 3 carbon atoms; Rf 3 represents a perfluoroalkyl group having 1 to 3 carbon atoms.

3. An electrophotographic photoreceptor having a surface layer, The surface layer is fluorine atom-containing resin particles; A binding material; A polymer A having a structural unit represented by the following formula (1), Contains the content of the structural unit represented by formula (1) in the polymer A is 5% by number or more and 95% by number or less of all structural units in the polymer A, the polymer A does not have a structural unit having an acidic group having a pKa of 3 or less; An electrophotographic photoreceptor characterized by: 【Transformation 5】 (In formula (1), R 11 represents a hydrogen atom or a methyl group; R 12 represents a single bond or a methylene group; Rf 1 and Rf 2 each independently represent a perfluoroalkylene group having 1 to 3 carbon atoms or a perfluoroalkylidene group having 1 to 3 carbon atoms; Rf 3 represents a perfluoroalkyl group having 1 to 3 carbon atoms.

4. 3. The electrophotographic photoreceptor according to claim 1, wherein the content of the structural unit represented by formula (1) in the polymer A is 5% by number or more and 95% by number or less of all structural units in the polymer A.

5. 4. The electrophotographic photoreceptor according to claim 1, wherein the content of the polymer A in the surface layer is from 2% by mass to 10% by mass relative to the mass of the fluorine atom-containing resin particles in the surface layer.

6. The electrophotographic photoreceptor according to any one of claims 2 to 5, wherein the polymer A further has a structural unit represented by the following formula (2): 【Transformation 6】 (In formula (2), Y Ａ１ represents an unsubstituted alkylene group, Y Ｂ represents an unsubstituted alkylene group, an alkylene group substituted with a halogen atom, an alkylene group substituted with a hydroxy group, an ester bond (-COO-), an amide bond (-NHCO-), a urethane bond (-NHCOO-), or a divalent linking group derived from a combination of one or more selected from these groups and bonds with -O- or -S-, or a single bond; Z Ａ represents a structure represented by the following formula (2A), a cyano group, or a phenyl group, R ２１ , and R ２２ each independently represents a hydrogen atom or a methyl group, m is an integer of 25 or more and 150 or less. 【Transformation 7】 (In formula (2A), Z Ａ１ represents an alkyl group having 1 to 4 carbon atoms.

7. The electrophotographic photoreceptor according to claim 1, wherein the total number of carbon atoms in Rf 1 to Rf 3 in formula (1) is 6 or more and 9 or less.

8. An electrophotographic photosensitive member described in any one of claims 1 to 7, wherein the content of the structural unit represented by formula (1) in polymer A is 0.1 mass% or more and 80 mass% or less with respect to all structural units in polymer A.

9. The electrophotographic photoreceptor according to claim 1, wherein the weight average molecular weight of the polymer A is 16,000 or more and 100,000 or less.

10. 8. The electrophotographic photoreceptor according to claim 1, wherein the polymer A has, as structural units, only the structural unit represented by the formula (1) and the structural unit represented by the formula (2).

11. 11. The electrophotographic photoreceptor according to claim 1, wherein the ratio of the structural unit represented by formula (1) to the structural unit represented by formula (2) in polymer A is 1:19 to 19:1 in terms of molar ratio.

12. 12. The electrophotographic photoreceptor according to claim 1, wherein the content of the fluorine atom-containing resin particles in the surface layer is 5% by mass or more and 40% by mass or less with respect to the total mass of the surface layer.

13. 13. The electrophotographic photoreceptor according to claim 1, wherein the binder material is a cured product of a hole transporting compound having a chain-polymerizable functional group.

14. 14. The electrophotographic photoreceptor according to claim 13, wherein the hole transporting compound having a chain polymerizable functional group is a compound represented by the following formula (CT-1) or (CT-2): 【Transformation 8】 (In the formula (CT-1), Ar １１ ~Ar １３ each independently represents a substituted aryl group or an unsubstituted aryl group, and the substituent that the substituted aryl group may have is an alkyl group having from 1 to 6 carbon atoms, or a monovalent functional group represented by any one of the following formulas (P-1) to (P-3), with the proviso that the compound represented by formula (CT-1) has at least one monovalent functional group represented by any one of the following formulas (P-1) to (P-3): 【Chemistry 9】 (In the formula (CT-2), Ar ２１ ~Ar ２４ each independently represents a substituted aryl group or an unsubstituted aryl group, Ar ２５ represents a substituted arylene group or an unsubstituted arylene group, and the substituent that the substituted aryl group may have is an alkyl group having from 1 to 6 carbon atoms, or a monovalent functional group represented by any of the following formulas (P-1) to (P-3), and the substituent that the substituted arylene group may have is an alkyl group having from 1 to 6 carbon atoms, or a monovalent functional group represented by any of the following formulas (P-1) to (P-3), with the proviso that the compound represented by formula (CT-2) has at least one monovalent functional group represented by any of the following formulas (P-1) to (P-3). 【Chemistry 10】 (In the formula (P-1), Z １１ represents a single bond or an alkylene group having 1 to 6 carbon atoms; X １１ represents a hydrogen atom or a methyl group.) 【Chemistry 11】 (In the formula (P-2), Z ２１ represents a single bond or an alkylene group having 1 to 6 carbon atoms. 【Chemistry 12】 (In the formula (P-3), Z ３１ represents a single bond or an alkylene group having 1 to 6 carbon atoms.

15. 15. The electrophotographic photoreceptor according to claim 1, wherein the content of the fluorine atom-containing resin particles in the surface layer is 20% by mass or more and 40% by mass or less with respect to the total mass of the surface layer.

16. The electrophotographic photoreceptor according to any one of claims 1 to 15, wherein the surface layer further contains a compound represented by the following formula (3): 【Chemistry 13】 (In formula (3), R ３１ represents an alkyl group or a fluoroalkyl group, and R ３２ represents a fluoroalkyl group.

17. 17. A process cartridge which integrally supports the electrophotographic photosensitive member according to any one of claims 1 to 16 and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means, and which is detachably mountable to a main body of an electrophotographic apparatus.

18. 17. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1, a charging unit, an exposure unit, a developing unit, and a transfer unit.

19. A method for manufacturing an electrophotographic photoreceptor having a surface layer, comprising: The manufacturing method comprises: a step of preparing a surface layer coating liquid containing a polymer A having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), at least one selected from a binder material and a raw material for the binder material, and fluorine atom-containing resin particles; and a step of forming a coating film of the surface layer coating liquid and drying and / or curing the coating film to form the surface layer; have 10. A method for producing an electrophotographic photosensitive member, comprising: 【Chemistry 14】 (In formula (1), R １１ represents a hydrogen atom or a methyl group, R １２ represents a single bond or a methylene group, Rf １ and Rf ２ each independently represents a perfluoroalkylene group having 1 to 3 carbon atoms or a perfluoroalkylidene group having 1 to 3 carbon atoms, Rf ３ represents a perfluoroalkyl group having 1 to 3 carbon atoms. 【Chemistry 15】 (In formula (2), Y A1 represents an unsubstituted alkylene group; Y B represents an unsubstituted alkylene group, an alkylene group substituted with a halogen atom, an alkylene group substituted with a hydroxy group, an ester bond (—COO—), an amide bond (—NHCO—), a urethane bond (—NHCOO—), or a divalent linking group derived by combining one or more selected from these groups and bonds with —O— or —S—, or a single bond; Z A represents a structure represented by the following formula (2A), a cyano group, or a phenyl group: R 21 and R 22 each independently represent a hydrogen atom or a methyl group; m is an integer of 25 or more and 150 or less. 【Chemistry 16】 (In formula (2A), Z A1 represents an alkyl group having 1 to 4 carbon atoms.) 20. A method for producing an electrophotographic photoreceptor having a surface layer, comprising: The manufacturing method comprises: a step of preparing a surface layer coating liquid containing a polymer A having a structural unit represented by the following formula (1), at least one selected from a binder material and a raw material for the binder material, and fluorine atom-containing resin particles; and a step of forming a coating film of the surface layer coating liquid and drying and / or curing the coating film to form the surface layer; and the content of the polymer A is 2% by mass or more and 10% by mass or less relative to the mass of the fluorine atom-containing resin particles in the surface layer; 10. A method for producing an electrophotographic photosensitive member, comprising: 【Chemistry 17】 (In formula (1), R 11 represents a hydrogen atom or a methyl group; R 12 represents a single bond or a methylene group; Rf 1 and Rf 2 each independently represent a perfluoroalkylene group having 1 to 3 carbon atoms or a perfluoroalkylidene group having 1 to 3 carbon atoms; Rf 3 represents a perfluoroalkyl group having 1 to 3 carbon atoms.

21. A method for producing an electrophotographic photoreceptor having a surface layer, comprising: The manufacturing method comprises: a step of preparing a surface layer coating liquid containing a polymer A having a structural unit represented by the following formula (1), at least one selected from a binder material and a raw material for the binder material, and fluorine atom-containing resin particles; and a step of forming a coating film of the surface layer coating liquid and drying and / or curing the coating film to form the surface layer; have the content of the structural unit represented by formula (1) in the polymer A is 5% by number or more and 95% by number or less of all structural units in the polymer A; 10. A method for producing an electrophotographic photosensitive member, comprising: [Chemistry 18] (In formula (1), R 11 represents a hydrogen atom or a methyl group; R 12 represents a single bond or a methylene group; Rf 1 and Rf 2 each independently represent a perfluoroalkylene group having 1 to 3 carbon atoms or a perfluoroalkylidene group having 1 to 3 carbon atoms; Rf 3 represents a perfluoroalkyl group having 1 to 3 carbon atoms.

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