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

Abstract

To provide an electrophotographic photoreceptor comprising a surface layer that features superior dispersibility of fluorine atom-containing resin particles and suppresses ghost images.SOLUTION: An electrophotographic photoreceptor is provided, comprising a surface layer containing fluorine atom-containing resin particles, a binding material, and a polymer A having a specific structural unit.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to an electrophotographic photosensitive member, a process cartridge having the electrophotographic photosensitive member, an electrophotographic apparatus having the electrophotographic photosensitive member, and a method for manufacturing an 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 in order to improve the dispersibility of the fluorine-containing resin particles. Patent Documents 2, 3, and 4 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 5 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] Japanese Patent Application Publication No. 2020-129058 [Patent Document 5] 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, 3, and 4 provide electrophotographic photoreceptors having a surface layer with excellent dispersibility of fluorine atom-containing resin particles, they may not be able to sufficiently suppress the occurrence of ghost images during repeated use of the electrophotographic photoreceptor. Therefore, there is room for improvement in suppressing the occurrence of ghost images during repeated use of the electrophotographic photoreceptor.

[0008] One aspect of the present disclosure is to provide an electrophotographic photoreceptor in which the occurrence of ghost images during repeated use is 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 including 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, With surface layer An electrophotographic photoreceptor , The surface layer is fluorine atom-containing resin particles; A binding material; Polymer A, Contains The binder material is Bisphenol Z polycarbonate resin, or A cured film obtained by polymerizing a composition containing a hole transporting compound represented by the following formula (B) and a compound represented by the following formula (C): and The polymer A but, A compound represented by the following formula (1) and a compound represented by the following formula (5) and a compound represented by the following formula (3): An electrophotographic photoreceptor is provided. [ka] [ka] [ka] (In formula (1), R 11 represents a hydrogen atom or a methyl group, R 12 represents a single bond, a methylene group, or an ethylene group, Rf 1 are each independently a group having 1 or more carbon atoms. 3 The following perfluoroalkylenes The base Show, Rf 2 represents a perfluoroalkyl group having 1 to 5 carbon atoms, n is an integer between 1 and 3, When n is 2 or 3, n Rf 1 may be the same or different.) [ka] (In formula (5), -Y A1 -Y B The structure indicated by - is -Y A1 -(Y A2 ) b -(Y A3 )c -(Y A4 ) d -(Y A5 ) e -(Y A6 ) f - is a structure represented by Y A1 represents a methylene group, Y A2 represents a methylene group substituted with a hydroxy group, Y A3 represents a methylene group, Y A4 indicates an ester bond, Y A5 represents a methylene group, Y A6 indicates a sulfur atom, b is 1, c is 1, d is 1, e is 1, f is 1, Z A represents a structure represented by the following formula (2A): R 51 represents a hydrogen atom or a methyl group, R 52 indicates a methyl group, m is an integer between 25 and 150.

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[0010] 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 mountable to the main body of the 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]

[0011] 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 the occurrence of ghost images during repeated use is suppressed. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic diagram illustrating an example of a configuration of an electrophotographic photoreceptor according to the present disclosure. [Figure 2] FIG. 1 is a diagram showing an example of a polishing machine using a polishing sheet. [Figure 3] FIG. 1 is a diagram illustrating an example of a process cartridge including an electrophotographic photosensitive member according to the present disclosure. [Figure 4] FIG. 1 is a diagram illustrating an example of an electrophotographic apparatus including an electrophotographic photoreceptor according to the present disclosure. [Figure 5] FIG. 1 is a schematic diagram showing an image signal used to evaluate ghosts. DETAILED DESCRIPTION OF THE INVENTION

[0013] As a result of investigations by the present inventors, it has been found that by incorporating polymer A obtained by polymerizing a composition containing fluorine atom-containing resin particles and a compound represented by the formula (1), a compound represented by the formula (2), and a compound represented by the formula (3) into the surface layer of an electrophotographic photosensitive member, it is possible to obtain an electrophotographic photosensitive member in which the dispersibility of the fluorine atom-containing resin particles in the surface layer is excellent and the occurrence of ghost images is suppressed.

[0014] That is, the present disclosure: With surface layer An electrophotographic photoreceptor , The surface layer is fluorine atom-containing resin particles; A binding material; Polymer A, Contains The binder material is Bisphenol Z polycarbonate resin, or A cured film obtained by polymerizing a composition containing a hole transporting compound represented by the following formula (B) and a compound represented by the following formula (C): and The polymer A but, A compound represented by the following formula (1): and , the following formula (5) A compound represented by and, A compound represented by the following formula (3): and, The electrophotographic photoreceptor is a polymer obtained by polymerizing a composition containing the compound. [ka] [ka] [ka] (In formula (1), R 11 represents a hydrogen atom or a methyl group, R 12 represents a single bond, a methylene group, or an ethylene group, Rf1 are each independently a group having 1 or more carbon atoms. 3 represents the following perfluoroalkylene group: Rf 2 represents a perfluoroalkyl group having 1 to 5 carbon atoms, n is an integer between 1 and 3, When n is 2 or 3, n Rf 1 may be the same or different.) [ka] (In formula (5), -Y A1 -Y B The structure indicated by - is -Y A1 -(Y A2 ) b -(Y A3 ) c -(Y A4 ) d -(Y A5 ) e -(Y A6 ) f - is a structure represented by Y A1 represents a methylene group, Y A2 represents a methylene group substituted with a hydroxy group, Y A3 represents a methylene group, Y A4 indicates an ester bond, Y A5 represents a methylene group, Y A6 indicates a sulfur atom, b is 1, c is 1, d is 1, e is 1, f is 1, Z A represents a structure represented by the following formula (2A): R 51 represents a hydrogen atom or a methyl group, R 52 indicates a methyl group, m is an integer between 25 and 150. [ka] (In formula (2A), Z A1 indicates a methyl group.) [ka] (In formula (3), R 31 represents a hydrogen atom or a methyl group, R 32 represents a phenyl group, a cyano group, or a group represented by the following formula (4): [ka] (In formula (4), R 41 teeth, Methyl )

[0015] The present disclosure also provides a method for producing an electrophotographic photoreceptor having a surface layer, comprising: fluorine atom-containing resin particles; At least one selected from a binding material and a raw material for a binding material; a polymer A obtained by copolymerizing a compound represented by the above formula (1), a compound represented by the above formula (2), and a compound represented by the above formula (3); A step of preparing a coating liquid for a surface layer containing the following: 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; The present invention provides a method for producing an electrophotographic photoreceptor having the above structure.

[0016] Although it is not excluded that polymer A has a structural unit having an acidic group with a pKa of 3 or less, it is preferable that polymer A does not have such a structural unit.

[0017] 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 sulfonic acid groups (methanesulfonic acid: -2.6), phosphonic acid groups (first dissociation: 1.5), phosphate groups (first dissociation: 2.12), and fluorinated alkylcarboxylic acid groups (e.g., trifluoroacetic acid: -0.25, difluoroacetic acid: 1.24, monofluoroacetic acid: 2.66).

[0018] The present inventors believe that the structure 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 a surface layer of an electrophotographic photosensitive member.

[0019] 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 the occurrence of ghost images during repeated use.

[0020] Electrophotographic photoreceptors having a surface layer containing fluorine atom-containing resin particles and a dispersant tend to easily produce ghost images during repeated use, which is thought to be because electric charges tend to accumulate in the fluorine atom-containing resin particles contained in the surface layer.

[0021] 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 discovered that the presence of an oxygen atom between the - chain has the effect of suppressing the retention of charges in fluorine-containing resin particles. However, when a polymer copolymerized with a macromonomer is used to impart dispersibility to fluorine-containing resin particles, although the dispersibility of the fluorine-containing resin particles is improved, the effect of suppressing the occurrence of ghost images is not sufficiently obtained. This is because -(CF2) n -Chain and-(CF2) n It is presumed that the presence of an oxygen atom between the - chain weakens the adhesive force to the fluorine-containing resin particles compared to when no oxygen atom is present, and the macromonomer moiety in the copolymer also adheres to the fluorine-containing resin particles, thereby weakening the adhesion to the fluorine-containing resin particles.

[0022] As a result of further investigations by the present inventors, it was found that by incorporating a copolymer obtained by further polymerizing the compound represented by the above formula (3) into the surface layer, charge retention can be suppressed and an electrophotographic photoreceptor can be obtained in which the occurrence of ghost images during repeated use is suppressed. The present inventors speculate that the reason for this is as follows. That is, because the side chain of the compound represented by formula (3) is short, spatial gaps are formed in the polymer, which facilitates molecular movement within the polymer, thereby eliminating steric constraints within the polymer. As a result, -(CF2)n- chains, which have a high affinity for fluorine-containing resin particles and are ultimately in an energetically stable state, are attached to the fluorine-containing resin particles.

[0023] In addition, Rf in the formula (1) 1 is a perfluoroalkylene group or a perfluoroalkylidene group, and it has been found that when the number of carbon atoms in each is 1 to 5, the effect of suppressing ghosting can be achieved. It is presumed that when the number of carbon atoms in the perfluoroalkylene group or perfluoroalkylidene group is greater than 5, charge retention occurs in the perfluoroalkylene group or perfluoroalkylidene group, and the effect of suppressing charge trapping via oxygen atoms cannot be achieved. In the above formula (1), Rf 2is a perfluoroalkyl group, and it was found that a ghost suppression effect can be achieved when the carbon number is between 1 and 5. It is speculated that when the carbon number of the above perfluoroalkyl group is more than 5, charge retention occurs in the perfluoroalkyl group, making it impossible to achieve the effect of suppressing charge trapping via oxygen atoms.

[0024] In addition, R in the formula (1) 12 It was found that the effect of suppressing ghosting can be achieved by changing the structural unit represented by formula (1) to a single bond, a methylene group, or an ethylene group. This is thought to reduce the difference in surface energy between the structural unit represented by formula (1) and the fluorine-containing resin particles, making it easier for the structural unit to adhere to the fluorine-containing resin particles and suppressing the retention of electric charges on the fluorine-containing resin particles.

[0025] <Fluorine atom-containing resin particles> The surface layer of the electrophotographic photoreceptor of the present disclosure contains fluorine atom-containing resin particles. 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.

[0026] When the protective layer of the electrophotographic photoreceptor is a surface layer, the content of the fluorine atom-containing resin particles is preferably 20% by mass or more and 40% by mass or less, more preferably 25% by mass or more and 35% by mass or less, relative to the protective layer.

[0027] When the photosensitive layer of the electrophotographic photoreceptor is a laminated photosensitive layer and the charge transport layer is a surface layer, the content of the fluorine atom-containing resin particles is preferably 5% by mass or more and 15% by mass or less, more preferably 7% by mass or more and 10% by mass or less, relative to the charge transport layer.

[0028] When the photosensitive layer of the electrophotographic photoreceptor is a single-layer type photosensitive layer and the photosensitive layer is a surface layer, the content of the fluorine atom-containing resin particles is preferably 5% by mass or more and 15% by mass or less relative to the photosensitive layer.

[0029] 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 resin.

[0030] The fluorine-containing resin particles preferably have an arithmetic mean of the major axes of primary particles (average primary particle size) measured from a secondary electron image of the surface layer observed by a scanning electron microscope in a cross-section of the surface layer with a scanning electron microscope, of 150 nm to 300 nm, from the viewpoints of improving dispersibility and suppressing the occurrence of ghost images.Furthermore, the fluorine-containing resin particles preferably have an average primary particle size of 180 nm to 250 nm.

[0031] 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.

[0032] 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.

[0033] (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) The fluorine atom-containing resin particles of the present disclosure may be used alone or in combination of two or more types.

[0034] <Binding material> The surface layer of the electrophotographic photoreceptor of the present disclosure contains a binder material. When the protective layer of the electrophotographic photoreceptor is the surface layer, the binder material is a cured film obtained by polymerizing a composition containing a monomer having a polymerizable functional group, and the monomer having a polymerizable functional group is the raw material of the binder material. Examples of the raw material of the binder material include monomers having a polymerizable functional group. Examples of the 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 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. The monomer having charge transport capability is preferably a compound represented by formula (CT-1) or (CT-2) described below. When the photosensitive layer of the electrophotographic photoreceptor is a laminated photosensitive layer and the charge transport layer is a surface layer, the binder material is a thermoplastic resin. Examples of the thermoplastic resin include polyester resin, polycarbonate resin, acrylic resin, and polystyrene resin. Among these, polycarbonate resin and polyester resin are preferred. As the polyester resin, polyarylate resin is particularly preferred. When the photosensitive layer of the electrophotographic photoreceptor is a single-layer photosensitive layer and the photosensitive layer is a surface layer, the binder material is a thermoplastic resin. Examples of the thermoplastic resin include polyester resin, polycarbonate resin, acrylic resin, and polystyrene resin. Among these, polycarbonate resin and polyester resin are preferred. As the polyester resin, polyarylate resin is particularly preferred.

[0035] <Compound represented by formula (1)> The surface layer of the electrophotographic photoreceptor of the present disclosure contains polymer A, which is a composition containing a compound represented by the following formula (1). [ka]

[0036] In the formula (1), R 11 is a hydrogen atom or a methyl group.12 is either a single bond, a methylene group, or an ethylene group. 12 If R is an alkylene having a large number of carbon atoms, the difference in surface energy between the polymer A and the fluorine atom-containing resin particles becomes large, making it difficult for them to adhere to each other sufficiently, and dispersibility tends to be insufficient. 12 is more preferably a methylene group. n Rf 1 Rf are each independently a perfluoroalkylene group having 1 to 5 carbon atoms or a perfluoroalkylidene group having 1 to 5 carbon atoms. 2 Rf is a perfluoroalkyl group having 1 to 5 carbon atoms. 1 , and Rf 2 If the number of carbon atoms is 6 or more, accumulation of electric charges in the fluorine atom-containing resin particles cannot be sufficiently suppressed, and the occurrence of ghost images cannot be sufficiently suppressed during repeated use of the electrophotographic photosensitive member.

[0037] In addition, in the formula (1), n ​​Rf 1 The number of carbon atoms and Rf 2 The total number of carbon atoms contained in the is preferably 5 or more and 8 or less.

[0038] In addition, in the formula (1), Rf 1 is a perfluoroalkylene group having 2 or 3 carbon atoms or a perfluoroalkylidene group having 2 or 3 carbon atoms, and Rf 2 is preferably a perfluoroalkyl group having 2 or 3 carbon atoms. n is an integer of 1 to 3, and when n is 2 or more, n Rf 1 may be the same or different. Furthermore, in the formula (1), n ​​is more preferably 1 or 2.

[0039] Examples of the compound represented by formula (1) used in the present disclosure include structures represented by formulas (1-1) to (1-14) below.

[0040] [ka]

[0041] <Compound represented by formula (2)> The surface layer of the electrophotographic photoreceptor of the present disclosure contains polymer A, which is a composition containing a compound represented by the following formula (2). [ka]

[0042] In the formula (2), R 21 is a hydrogen atom or a methyl group. Y is a divalent organic group. Z is a polymer moiety. It is preferable that -YZ in the formula (2) does not have an acidic group with a pKa of 3 or less. It is preferable that -YZ in the formula (2) does not have -SO3H.

[0043] In the formula (2), Z is preferably a polymer moiety having a structural unit represented by the following formula (b-1): Z preferably has a total of 25 to 150 structural units represented by (b-1). [ka] In formula (b-1), R 201 represents a hydrogen atom or a methyl group, and R 202 is a structure represented by the following formula (2A), a cyano group, or a phenyl group. [ka] In the above formula (2A), Z A1 is an alkyl group having 1 to 4 carbon atoms.

[0044] The terminal of the polymer moiety represented by Z in the formula (2) may be terminated using a terminal capping agent or may have a hydrogen atom.

[0045] The compound represented by the formula (2) is preferably a compound represented by the following formula (5). [ka] In the formula (5), 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 the structure represented by formula (2A), a cyano group, or a phenyl group, and R 51 , R 52 represents a hydrogen atom or a methyl group, and m represents an integer of 25 or more and 150 or less.

[0046] In formula (5), 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 (5), 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 (5), 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-.

[0047] -Y in the formula (5) A1 -Y B -Y A1-(Y A2 ) b -(Y A3 ) c -(Y A4 ) d -(Y A5 ) e -(Y A6 ) f Preferably, the structure is represented by -. Y A1 represents an unsubstituted alkylene group, and 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, and Y A3 represents an unsubstituted alkylene group, and Y A4 represents an ester bond, an amide bond, or a urethane bond, and Y A5 represents an unsubstituted alkylene group, and Y A6 represents an oxygen atom or a sulfur atom, and b, c, d, e, and f each independently represent 0 or 1. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, and a hexylene group. Among these, a methylene group, an ethylene group, and a propylene group are preferred.

[0048] Further specific examples of the compound represented by formula (5) include the following compounds: Particularly preferred examples include the compound represented by (A) described below. [Table 1-1] [Table 1-2]

[0049] <Compound represented by formula (3)> The surface layer of the electrophotographic photoreceptor of the present disclosure contains polymer A, which is a composition containing a compound represented by the following formula (3). [ka] In the formula (3), R 31 is a hydrogen atom or a methyl group.32 represents a phenyl group, a substituent represented by formula (4), or a cyano group. [ka] (In formula (4), R 41 represents an alkyl group having 1 to 4 carbon atoms.

[0050] Furthermore, from the viewpoint of suppressing the occurrence of ghost images, R 41 is more preferably a methyl group.

[0051] Further specific examples of the compound represented by formula (3) include the following compounds: A particularly preferred example is the compound represented by formula (3-6). [ka]

[0052] In the composition, the ratio of the compound represented by formula (3) to the compound represented by formula (1) is preferably 0.05 mol % or more and 2.0 mol % or less, more preferably 0.10 mol % or more and 1.0 mol % or less, and even more preferably 0.10 mol % or more and 0.50 mol % or less.

[0053] Polymer A may be a random copolymer, an alternating copolymer, or a block copolymer. The polymer A can have structural units of the following formulae (101), (201), and (301). [ka] (In formula (101), R 11 represents a hydrogen atom or a methyl group. R 12 represents a single bond, a methylene group, or an ethylene group. Rf 1 each independently represents a perfluoroalkylene group having 1 to 5 carbon atoms or a perfluoroalkylidene group having 1 to 5 carbon atoms. Rf 2 represents a perfluoroalkyl group having 1 to 5 carbon atoms. n is an integer between 1 and 3. When n is 2 or 3, n Rf 1 may be the same or different.) [ka] (In formula (201), R 21 represents a hydrogen atom or a methyl group. Y represents a divalent organic group. Z represents a polymer moiety. [ka] (In formula (301), R 31 represents a hydrogen atom or a methyl group. R 32 represents a phenyl group, a cyano group, or a group represented by the following formula (4): [ka] (In formula (4), R 41 represents an alkyl group having 1 to 4 carbon atoms.

[0054] An example of the polymer A is a compound represented by the following formula (c). [ka]

[0055] It is more preferable that the polymer A is a polymer obtained by polymerizing only the compound represented by the formula (1), the compound represented by the formula (2), and the compound represented by the formula (3).

[0056] In the polymer A contained in the surface layer of the electrophotographic photoreceptor of the present disclosure, the structural unit derived from the compound represented by the formula (1) is preferably 5 mol % or more and 95 mol % or less, more preferably 50 mol % or more and 95 mol % or less, and even more preferably 70 mol % or more and 90 mol % or less, based on the total content of all structural units possessed by the polymer A, from the viewpoint of improving the dispersibility of the fluorine atom-containing resin particles.

[0057] Of the polymer A contained in the surface layer of the electrophotographic photoreceptor of the present disclosure, the structural unit derived from the compound represented by formula (1) is preferably 0.1% by mass or more and 80% by mass or less, more preferably 1% by mass or more and 80% by mass or less, and even more preferably 4% by mass or more and 66% by mass or less.

[0058] In polymer A, the molar ratio of the structural units derived from the compound represented by formula (1) to the structural units derived from the compound 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.

[0059] From the viewpoints of improving the dispersibility of fluorine-containing resin particles and suppressing the occurrence of ghost images, the weight-average molecular weight of the polymer A contained in the surface layer of the electrophotographic photoreceptor of the present disclosure is preferably 16,000 or more and 100,000 or less. Furthermore, the weight-average molecular weight of the polymer A in the composition containing (1), (2), and (3) is more preferably 18,000 or more and 80,000 or less.

[0060] The weight average molecular weight of polymer A can be measured and calculated by the following method. (Weight average molecular weight measured by GPC) The weight average molecular weight according to the present disclosure can be 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.

[0061] The content of polymer A of the composition containing (1), (2), and (3) in the surface layer relative to the fluorine atom-containing resin particles is preferably 2% by mass or more and 10% by mass or less, more preferably 4% by mass or more and 8% by mass or less, from the viewpoint of improving dispersibility and suppressing the occurrence of ghost images.

[0062] <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.

[0063] The surface layer of the electrophotographic photoreceptor of the present disclosure contains fluorine atom-containing resin particles and a polymer A of a composition including the compound represented by the formula (1), the compound represented by the formula (2), and the compound represented by the formula (3).

[0064] 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.

[0065] The configuration of the electrophotographic photoreceptor of the present disclosure will be described below. <Support> The electrophotographic photoreceptor of the present disclosure preferably has a support. The support of the electrophotographic photoreceptor is preferably conductive (conductive support). The support may have a cylindrical, belt-like, or sheet-like shape. 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.

[0066] <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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] The average 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.

[0071] <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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] The average thickness of the undercoat layer is preferably from 0.1 μm to 50 μm, more preferably from 0.2 μm to 40 μm, and particularly preferably from 0.3 μm to 30 μm.

[0080] <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.

[0081] (1) Laminated photosensitive layer The laminated photosensitive layer has a charge generating layer and a charge transport layer.

[0082] (1-1) Charge generation layer The charge generating layer preferably contains a charge generating material and a resin.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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 the coating film on an underlayer such as an 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.

[0087] The average thickness of the charge generating layer is preferably from 0.1 μm to 1 μm, and more preferably from 0.15 μm to 0.4 μm.

[0088] (1-2) Charge transport layer The charge transport layer preferably contains a charge transport material and a resin.

[0089] Examples of charge transport materials include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these materials. Among these, triarylamine compounds and benzidine compounds are preferred. 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.

[0090] Examples of the resin include polyester resin, polycarbonate resin, acrylic resin, polystyrene resin, etc. Among these, polycarbonate resin and polyester resin are preferred. As the polyester resin, polyarylate resin is 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.

[0091] When the photosensitive layer is a laminated type photosensitive layer and does not have a protective layer (described later), the charge transport layer serves as the surface layer. In this case, the charge transport layer contains fluorine atom-containing resin particles, a binder material, and polymer A having a composition containing the compound represented by formula (1), the compound represented by formula (2), and the compound represented by formula (3).

[0092] 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.

[0093] 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.

[0094] The average thickness of the charge transport layer is preferably from 5 μm to 50 μm, more preferably from 8 μm to 40 μm, and particularly preferably from 10 μm to 30 μm.

[0095] (2) Single-layer photosensitive layer A 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 this coating film on an underlayer such as an undercoat layer, and drying it. The charge generating material, charge transport material, and resin are the same as those exemplified for the material in "(1) Multilayer Photosensitive Layer" above. When the photosensitive layer is a single-layer photosensitive layer and does not have a protective layer (described later), the photosensitive layer becomes the surface layer.

[0096] <Protective layer> In the present invention, a protective layer may be provided on the photosensitive layer, which can improve durability.

[0097] The protective layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of the reaction include thermal polymerization, photopolymerization, and radiation polymerization. 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 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 a polymerizable functional group.

[0098] The monomer having charge transporting ability is 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 from 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 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), and 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).

[0099] [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.

[0100] 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 polymer A.

[0101] 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.

[0102] The protective layer can be formed by preparing a coating solution for the protective layer containing the above-mentioned materials and solvent, forming this coating film on the photosensitive layer, and drying and / or curing it. Examples of solvents 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. Alcohol-based solvents are preferred because they do not dissolve the underlying photosensitive layer.

[0103] The average 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.

[0104] <Surface treatment of electrophotographic photoreceptors> In the present disclosure, the surface of the electrophotographic photosensitive member may be subjected to 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.

[0105] 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).

[0106] 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.

[0107] <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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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, followed by drying.

[0113] <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 guide rollers 2-2c and 2-2d by the motor (not shown) onto a take-up device 2-5. Polishing is performed by constantly pressing the abrasive sheet 2-1 against the workpiece (the 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 contact area of ​​the abrasive sheet 2-1.

[0114] The feed speed of the abrasive sheet 2-1 is preferably 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.

[0115] 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.

[0116] The pressing pressure of the backup roller 2-3 against the object to be processed 2-4 is 0.005 to 15 N / m, although it depends on the hardness and polishing time of the backup roller 2-3. 2 This is preferable.

[0117] 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 base material, etc.

[0118] <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. Surface roughness meters such as the Surf Coader SE3500 type surface roughness measuring instrument manufactured by Kosaka Laboratory Ltd. Non-contact three-dimensional surface measuring machine Micromap 557N manufactured by Hishikawa System Co., Ltd. Microscopes capable of acquiring three-dimensional shapes such as the ultra-depth shape measuring microscope VK-8550 and VK-9000 manufactured by Keyence Corporation. 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). Also, in the present disclosure, for the range of a 5 mm square section of the electrophotographic photoreceptor cut out as a specimen for X-ray photoelectron spectroscopy described later, Rmax is measured in advance. The measurement is performed arbitrarily at three locations in the range of 5 mm square, and the average value is adopted as the polishing depth L (μm).

[0119] <Process cartridge, electrophotographic apparatus> The electrophotographic photoreceptor of the present disclosure may be one of the components of a process cartridge or an electrophotographic apparatus. The process cartridge integrally supports the electrophotographic photoreceptor described so far and at least one means selected from the group consisting of charging means, developing means, transfer means, and cleaning means, and is detachable from the electrophotographic apparatus main body. Further, the electrophotographic apparatus has the electrophotographic photoreceptor, charging means, exposure means, developing means, and transfer means described so far.

[0120] FIG. 3 shows the configuration of a process cartridge equipped with the electrophotographic photosensitive member of the present disclosure, and FIG. 4 shows an example of the schematic configuration of an electrophotographic apparatus having the process cartridge of FIG.

[0121] In Figure 3, 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.

[0122] 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.

[0123] 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.

[0124] 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 may be 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, and the process cartridge 9 may be configured to be detachably attachable to the main body of the electrophotographic apparatus. In FIG. 3, the electrophotographic photosensitive member 1, charging means 2, developing means 4, and cleaning means 8 are integrally supported to form the process cartridge 9 that is detachably attachable to the main body of the electrophotographic apparatus.

[0125] An example of the configuration of the electrophotographic apparatus of the present disclosure is shown in Figure 4. 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.

[0126] 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 intermediate transfer body 10. The toner image on intermediate transfer body 10 is transferred to transfer paper 11 by a transfer bias from secondary transfer means 14. The toner image transferred onto transfer paper 11 is transported along paper feed path 12, fixed on transfer paper 11 by fixing means 15, and then discharged from paper discharge section 16. [Example]

[0127] 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.

[0128] <Synthesis of Polymer A> In the present disclosure, polymers and the like of compositions containing (1), (2), and (3) (hereinafter also referred to as "graft copolymers") were synthesized as follows. The acrylate compounds and macromonomer compounds used in the following synthesis examples can be produced by referring to, for example, JP 2009-104145 A.

[0129] (Graft copolymer 1) 100 parts of 1H,1H-Perfluoro(2,5-dimethyl-3,6-dioxanonanoyl) acrylate (manufactured by Sigma-Aldrich) which is the compound represented by formula (1-1), 139.89 parts of a macromonomer (number average molecular weight 6,000) represented by the following formula (A) which is the compound represented by formula (2), 0.093 parts of methyl methacrylate which is the compound represented by formula (3), 1,1'-Azobis(1-acetoxy-1-phenylethane) (trade name: OTAZO-15, Otsuka Chemical Co., Ltd.), In a glass flask equipped with a stirrer, reflux condenser, nitrogen gas inlet tube, thermostatic bath, and thermometer, 0.874 parts of n-butyl acetate and 676 parts of n-butyl acetate were mixed 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 3,000 parts of 2-propanol were added to obtain a precipitate. This precipitate was washed with a mixed solvent of n-butyl acetate and 2-propanol in a ratio of 1:5 and dried at 80°C for 3 hours under reduced pressure of 1,325 PA or less to obtain graft copolymer 1. [ka]

[0130] (Graft copolymers 2-39) Graft copolymers 2 to 39 were obtained in the same manner as for graft copolymer 1, except that the compounds represented by formulas (1) to (3) were changed to the compounds shown in Table 2 in terms of parts by mass.

[0131] In graft copolymers 37 to 39, instead of the compound represented by formula (1), compounds represented by the following formulas (a-1) and (a-2), which do not fall under the category of compounds represented by formula (1), were used. [ka]

[0132] The resulting graft copolymers 1 to 39 were subjected to GPC measurement by the method described above, and the weight average molecular weights were calculated. The results are shown in Table 2.

[0133] [Table 2]

[0134] <Preparation 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.

[0135] (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.

[0136] 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.

[0137] The obtained coating liquid for undercoat layer was dip-coated onto the support to form a coating film, and the coating film was dried at 160° C. for 30 minutes to form undercoat layer 1 with a film thickness of 18 μm.

[0138] (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]

[0139] (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 structural 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] (In formula (I), 0.95 and 0.05 represent the molar ratio (copolymerization ratio) of the two structural units.)

[0140] (Protective layer 1) 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. 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] The prepared protective layer coating solution was dip-coated onto the charge transport layer 1 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, in a nitrogen atmosphere, the coating film was heat-treated for 15 seconds under conditions where the temperature of the coating film reached 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 until the temperature reached 25°C, and then heat-treated for 1 hour under conditions where the temperature of the coating film reached 105°C, forming a surface layer (protective layer 1) with a thickness of 5 μm.

[0141] In this manner, an electrophotographic photoreceptor having a support and a surface layer before surface polishing was prepared.

[0142] <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 above-mentioned polishing device 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.

[0143] (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 performed at three arbitrary locations within a 5 mm range, 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

[0144] [Examples 1-2 to 1-41, Comparative Examples 1-1 to 1-6] An electrophotographic photoreceptor was prepared in the same manner as in Example 1-1, except that in forming the protective layer, the type and mass part of the graft copolymer and the average primary particle size of the polytetrafluoroethylene resin particles were changed to those shown in Tables 3 and 4.

[0145] [Table 3]

[0146] [Table 4]

[0147] <Evaluation of Electrophotographic Photoreceptors> The electrophotographic photoreceptors obtained in Examples 1-1 to 1-41 and Comparative Examples 1-1 to 1-6 were evaluated as follows.

[0148] [Evaluation device 1-1] The electrophotographic photoreceptors prepared in Examples 1-1 to 1-41 and Comparative Examples 1-1 to 1-6 were installed in a copying machine ImagePRESS C910 (product name) manufactured by Canon Inc., and evaluated. Specifically, the prepared electrophotographic photosensitive member was mounted in a magenta process cartridge, which was then mounted in the station of the magenta process cartridge, and evaluation was carried out. The above evaluation device was placed in an environment of a temperature of 10°C and a relative humidity of 10%RH, 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 carried out.

[0149] [Evaluation device 1-2] The electrophotographic photoreceptors prepared in Examples 1-1 to 1-41 and Comparative Examples 1-1 to 1-6 were mounted on a modified copy machine of Canon Inc.'s ImagePRESS C910 (product name) (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 exposure means was a laser image exposure system (wavelength 680 nm)) and evaluated. Specifically, the evaluation device was placed in an environment of 10°C temperature and 10% 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 −900V and the exposure potential was −400V, and the charging potential and the exposure amount of the exposure means were adjusted.

[0150] 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 set to 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, manufactured by Trek Japan Co., Ltd.).

[0151] (Initial image evaluation) Image evaluation was performed using the above-mentioned evaluation device 1-1. A solid white image was output on A4-size glossy 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 the present invention, ranks A, B, C, and D represent levels at which the effects of the present invention are achieved, with rank A being judged to be an excellent level. Rank E, on the other hand, was judged to be a level at which the effects of the present invention 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 larger in diameter The results of the evaluation are shown in Table 5.

[0152] (Ghost Rating) The ghost evaluation was performed by repeatedly outputting images using the evaluation device 1-1 described above, followed by measuring the ghost potential using the evaluation device 1-2 described above. A cartridge containing an electrophotographic photoreceptor was attached to the evaluation device 1-1, and 25,000 sheets of A4-size plain paper were repeatedly printed with a monochrome text image at a coverage rate of 1%. The electrophotographic photoreceptor that had been repeatedly used was then attached to the cartridge and attached to the evaluation device 1-2. The ghost potential was measured by inputting a signal outputting the image shown in Figure 5 into the evaluation device 1-2. The image for ghost evaluation, as shown in Figure 5(a), was an image in which a square solid image (black image) was displayed on a white background (white image) at the beginning of the image, followed by the one-dot knight's horse pattern image shown in Figure 5(b). In the evaluation device 1-2, the aforementioned potential measurement probe was fixed so that it was positioned at the position of the square solid image (black image) in the signal outputting the image shown in Figure 5. The applied bias was set so that the dark potential of the non-exposed portion of the electrophotographic photosensitive member was −900V, and the exposure amount of the exposure means was adjusted so that the exposure potential was −400V. An electrostatic latent image corresponding to the image shown in Fig. 5 is formed on the surface of the photoconductor by a signal that outputs the image shown in Fig. 5. In the electrostatic latent image corresponding to the image shown in Fig. 5, the potential difference between the potential of the ghost image generating region in the knight's knight pattern image forming region and the potential of the region other than the ghost image generating region in the knight's knight pattern image forming region was defined as the ghost potential. In the same manner, image formation was repeated for 60,000 sheets and 80,000 sheets, and then the ghost potential was evaluated.The lower the ghost potential, the better, and the more the effect of the present invention was obtained. The results of the evaluation are shown in Table 5.

[0153] [Table 5]

[0154] 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.

[0155] (Undercoat layer 2) Zinc oxide particles (average particle diameter: 70 nm, specific surface area: 15 m 2 Sixty 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.

[0156] 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 anthraquinone 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.

[0157] 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.

[0158] (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.

[0159] (Charge transport layer 2) 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 20 parts of tetrahydrofuran were mixed and stirred for 48 hours while maintaining the liquid temperature at 20°C to obtain Preparation A.

[0160] Next, 45.0 parts of N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine, 55.0 parts of bisphenol Z-type polycarbonate resin (viscosity average molecular weight 40,000), and 0.30 parts of 2,6-di-t-butyl-4-methylphenol as an antioxidant were mixed, and 280 parts of tetrahydrofuran was added and dissolved to obtain Preparation B.

[0161] 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. 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.

[0162] This charge transport layer coating liquid was dip coated onto the charge generation layer 2 to form a coating film, and the resulting coating film was dried at 135° C. for 40 minutes to form a charge transport layer 2 having a thickness of 33 μm. In this way, an electrophotographic photoreceptor was prepared.

[0163] [Examples 2-2 to 2-41, Comparative Examples 2-1 to 2-6] An electrophotographic photoreceptor was prepared in the same manner as in Example 2-1, except that in forming the charge transport layer, the type and mass part of the graft copolymer and the average primary particle size of the polytetrafluoroethylene resin particles were changed to those shown in Tables 6 and 7.

[0164] [Table 6]

[0165] [Table 7]

[0166] <Evaluation of Electrophotographic Photoreceptors> The electrophotographic photoreceptors produced using the electrophotographic photoreceptors obtained in Examples 2-1 to 2-41 and Comparative Examples 2-1 to 2-6 were evaluated as follows.

[0167] [Evaluation device 2-1] The electrophotographic photoreceptor prepared using the electrophotographic photoreceptor was mounted on a copying machine, imageRUNNER ADVANCE DX C3835F (product name), manufactured by Canon Inc., and evaluated. Specifically, the evaluation device was placed in an environment of 10°C temperature and 10% 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.

[0168] [Evaluation device 2-2] The electrophotographic photosensitive members prepared in Examples 2-1 to 2-40 and Comparative Examples 2-1 to 2-6 were mounted on a modified copy machine of imageRUNNER ADVANCE DX C3835F (product name) manufactured by Canon Inc. (charging means was a system in which a DC voltage was applied to a roller-type contact charging member (charging roller), and exposure means was a laser image exposure system (wavelength 780 nm)), and evaluation was carried out. Specifically, the evaluation device was placed in an environment of a temperature of 10°C and a relative humidity of 10% RH, and the prepared electrophotographic photosensitive members were mounted on a process cartridge for magenta, which was then mounted on the station of the magenta process cartridge, and evaluation was carried out. 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.).

[0169] (Initial image evaluation) Image evaluation was performed using the evaluation device 2-1 described above. A solid white image was printed on A4-size glossy 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 the present invention, ranks A, B, C, and D represent levels at which the effects of the present invention are achieved, with rank A being judged to be an excellent level. Rank E, on the other hand, was judged to be a level at which the effects of the present invention 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 larger in diameter The results of the evaluation are shown in Table 7.

[0170] (Ghost Rating) The ghost was evaluated by repeatedly outputting images as follows using the evaluation device 2-1, and then measuring the ghost potential using the evaluation device 2-2. A cartridge equipped with an electrophotographic photoreceptor was installed in Evaluation Apparatus 1-1, and a monochrome text image with a 1% print rate was repeatedly printed on 20,000 sheets of A4-sized plain paper. The electrophotographic photoreceptor that had been repeatedly used was then installed in the cartridge and installed in Evaluation Apparatus 1-2. The ghost potential was measured by inputting a signal outputting the ghost evaluation image shown in Figure 5 into Evaluation Apparatus 1-2. The ghost evaluation image, as shown in Figure 5(a), was an image in which a square solid image (black image) was displayed on a white background (white image) at the beginning of the image, followed by the one-dot knight's horse pattern image shown in Figure 5(b). In Evaluation Apparatus 1-2, the aforementioned potential measurement probe was fixed so that it was positioned at the position of the square solid image (black image) in the signal outputting the image shown in Figure 5. The applied bias was set so that the dark potential of the non-exposed area of ​​the electrophotographic photosensitive member was −500 V, and the laser light intensity was 0.30 μJ / cm 2 An electrostatic latent image corresponding to the image shown in Fig. 5 is formed on the surface of the photoconductor by a signal that outputs the image shown in Fig. 5. In the electrostatic latent image corresponding to the image shown in Fig. 5, the potential difference between the potential of the ghost image generating region in the knight's knight pattern image forming region and the potential of the region other than the ghost image generating region in the knight's knight pattern image forming region was defined as the ghost potential. In the same manner, image formation was repeated for 40,000 sheets and 55,000 sheets, and then the ghost potential was evaluated.The lower the ghost potential, the better, and the more the effect of the present invention was obtained. The results of the evaluation are shown in Table 8.

[0171] [Table 8] [Explanation of symbols]

[0172] 101 Base 102 Undercoat layer 103 Charge generation layer 104 Charge transport layer 105 Surface layer 2-1 Polishing sheet 2-2a Guide roller 2-2b Guide roller 2-2c Guide roller 2-2d Guide Roller 2-3 Backup roller 2-4 Object to be treated 2-5 Winding method 2-6 Shaft 1 Electrophotographic photoreceptor 2. Charging means 3 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 Fixation Method 16 Paper output section 17 Yellow process cartridge 18 Magenta process cartridge 19 Cyan process cartridge 20 Black process cartridge 41 White Images 42 Black Images 43 1-dot knight pattern image 44 Ghost Images

Claims

1. An electrophotographic photoreceptor having a surface layer, The surface layer is fluorine atom-containing resin particles; A binding material; Polymer A, and Contains The binder material is Bisphenol Z polycarbonate resin, or A cured film obtained by polymerizing a composition containing a hole transporting compound represented by the following formula (B) and a compound represented by the following formula (C): and The polymer A is a polymer obtained by polymerizing a composition containing a compound represented by the following formula (1), a compound represented by the following formula (5), and a compound represented by the following formula (3): An electrophotographic photoreceptor characterized by the above-mentioned. 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 (In formula (1), R １１ represents a hydrogen atom or a methyl group, R １２ represents a single bond, a methylene group, or an ethylene group, Rf １ each independently represents a perfluoroalkylene group having 1 to 3 carbon atoms, Rf ２ represents a perfluoroalkyl group having 1 to 5 carbon atoms, n is an integer of 1 to 3, When n is 2 or 3, n Rf １ may be the same or different.) 【Chemistry 4】 (In formula (5), The structure represented by -Y A1 -Y B - is a structure represented by -Y A1 -(Y A2 ) b -(Y A3 ) c -(Y A4 ) d -(Y A5 ) e -(Y A6 ) f -, Y A1 represents a methylene group; Y A2 represents a methylene group substituted with a hydroxy group; Y A3 represents a methylene group; Y A4 represents an ester bond; Y A5 represents a methylene group; Y A6 represents a sulfur atom; b is 1; c is 1; d is 1, e is 1, f is 1, Z A represents a structure represented by the following formula (2A): R 51 represents a hydrogen atom or a methyl group; R 52 represents a methyl group; m is an integer of 25 or more and 150 or less. 【Transformation 5】 (In formula (2A), Z A1 represents a methyl group.) 【Transformation 6】 (In formula (3), R ３１ represents a hydrogen atom or a methyl group, R ３２ represents a phenyl group, a cyano group, or a group represented by the following formula (4): 【Transformation 7】 (In formula (4), R ４１ indicates a methyl group.)

2. In the formula (1), n ​​Rf １ , and Rf ２ 2. The electrophotographic photoreceptor according to claim 1, wherein the total number of carbon atoms is 5 or more and 8 or less.

3. 3. The electrophotographic photoreceptor according to claim 1, wherein n in formula (1) is 1 or 2.

4. Rf in the formula (1) １ is a perfluoroalkylene group having 2 or 3 carbon atoms, and Rf ２ 4. The electrophotographic photoreceptor according to claim 1, wherein is a perfluoroalkyl group having 2 or 3 carbon atoms.

5. R in the formula (3) ３２ The electrophotographic photoreceptor according to any one of claims 1 to 4, wherein is a group represented by the formula (4).

6. the content of the compound represented by formula (1) in the composition is 5 mol % or more and 95 mol % or less with respect to the total content of the compound represented by formula (1), the compound represented by formula (5), and the compound represented by formula (3) in the composition; the content of the compound represented by formula (3) in the composition is 0.10 mol % or more and 1.0 mol % or less relative to the content of the compound represented by formula (1) in the composition; The electrophotographic photoreceptor according to any one of claims 1 to 5.

7. 7. The electrophotographic photoreceptor according to claim 6, wherein the content of the compound represented by formula (3) in the composition is 0.10 mol % or more and 0.50 mol % or less with respect to the content of the compound represented by formula (1) in the composition.

8. The electrophotographic photoreceptor according to any one of claims 1 to 7, wherein the polymer A is a polymer obtained by polymerizing only the compound represented by formula (1), the compound represented by formula (5), and the compound represented by formula (3).

9. 9. The electrophotographic photoreceptor according to claim 1, wherein the content of the polymer A in the surface layer is 2% by mass or more and 10% by mass or less with respect to the mass of the fluorine atom-containing resin particles in the surface layer.

10. 10. 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.

11. 11. 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.

12. the fluorine atom-containing resin particles are polytetrafluoroethylene resin particles, 12. The electrophotographic photoreceptor according to claim 1, wherein, in cross-sectional observation of the surface layer, the arithmetic mean of the major axis of primary particles measured from a secondary electron image of the polytetrafluoroethylene resin particles by a scanning electron microscope is 150 nm or more and 300 nm or less.

13. 13. A process cartridge which integrally supports the electrophotographic photosensitive member according to any one of claims 1 to 12 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 a main body of an electrophotographic apparatus.

14. 13. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1, a charging unit, an exposing unit, a developing unit, and a transferring unit.

15. A method for manufacturing an electrophotographic photoreceptor having a surface layer, comprising: The manufacturing method comprises: fluorine atom-containing resin particles; a bisphenol Z-type polycarbonate resin as a binder material, or a hole transport compound represented by the following formula (B) and a compound represented by the following formula (C) as raw materials for the binder material; a polymer A obtained by copolymerizing a compound represented by the following formula (1), a compound represented by the following formula (5), and a compound represented by the following formula (3); A step of preparing a coating liquid for a surface layer containing the following: 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; having 10. A method for producing an electrophotographic photosensitive member, comprising: 【Transformation 8】 【Chemistry 9】 【Chemistry 10】 (In formula (1), R １１ represents a hydrogen atom or a methyl group, R １２ represents a single bond, a methylene group, or an ethylene group, Rf １ each independently represents a perfluoroalkylene group having 1 to 3 carbon atoms, Rf ２ represents a perfluoroalkyl group having 1 to 5 carbon atoms, n is an integer of 1 to 3, When n is 2 or 3, n Rf １ may be the same or different.) 【Chemistry 11】 (In formula (5), The structure represented by -Y A1 -Y B - is a structure represented by -Y A1 -(Y A2 ) b -(Y A3 ) c -(Y A4 ) d -(Y A5 ) e -(Y A6 ) f -, Y A1 represents a methylene group; Y A2 represents a methylene group substituted with a hydroxy group; Y A3 represents a methylene group; Y A4 represents an ester bond; Y A5 represents a methylene group; Y A6 represents a sulfur atom; b is 1; c is 1; d is 1, e is 1, f is 1, Z A represents a structure represented by the following formula (2A): R 51 represents a hydrogen atom or a methyl group; R 52 represents a methyl group; m is an integer of 25 or more and 150 or less. 【Chemistry 12】 (In formula (2A), Z A1 represents a methyl group.) 【Chemistry 13】 (In formula (3), R ３１ represents a hydrogen atom or a methyl group, R ３２ represents a phenyl group, a cyano group, or a group represented by the following formula (4): 【Chemistry 14】 (In formula (4), R ４１ indicates a methyl group.)

Images