Electrophotographic photoreceptor, process cartridge, electrophotographic device, and method of 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] This disclosure relates to an electrophotographic photoreceptor, a process cartridge having the electrophotographic photoreceptor, an electrophotographic apparatus having the electrophotographic photoreceptor, and a method for manufacturing an electrophotographic photoreceptor. [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 improve image quality during repeated use.

[0003] One technique for improving the wear resistance of electrophotographic photoreceptors is to incorporate fluorine atom-containing resin particles into the surface layer of the electrophotographic photoreceptor, thereby reducing friction between the surface layer and contact members such as cleaning blades. 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 atom-containing resin particles, a method is known in which a fluorine atom-containing (meth)acrylic polymer is used as a dispersant to improve the dispersibility of the fluorine atom-containing resin particles. Patent documents 2, 3, and 4 disclose a technique for improving the dispersibility of fluorine atom-containing resin particles by using a fluorine atom-containing (meth)acrylic polymer of a specific structure as a dispersant.

[0005] Patent Document 5 discloses an electrophotographic photoreceptor having a surface layer containing a fluorine-based graft polymer and fluorine-containing resin particles, wherein the fluorine-based graft polymer contains structural units having acidic groups 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 Publication No. 2012-189715 [Patent Document 3] Japanese Patent Publication No. 2009-104145 [Patent Document 4] Japanese Patent Publication No. 2020-129058 [Patent Document 5] Japanese Patent Publication No. 2021-47236 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, while the technologies disclosed in Patent Documents 2, 3, and 4 provide an electrophotographic photoreceptor having a surface layer with excellent dispersibility of fluorine atom-containing resin particles, they sometimes fail to sufficiently suppress the occurrence of ghost images during repeated use of the electrophotographic photoreceptor. Therefore, there was room for improvement in suppressing the occurrence of ghost images during repeated use of the electrophotographic photoreceptor.

[0008] One aspect of this disclosure aims to provide an electrophotographic photoreceptor in which the occurrence of ghost images during repeated use is suppressed. Another aspect of this disclosure is toward providing a process cartridge equipped with the electrophotographic photoreceptor, and an electrophotographic apparatus equipped with the process cartridge. Another aspect of this disclosure is toward providing a method for manufacturing the electrophotographic photoreceptor. [Means for solving the problem]

[0009] According to one aspect of this disclosure, Having a surface layer, The surface layer Fluorine atom-containing resin particles, Binding material and, Polymer A and, It contains, 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 (2), and a compound represented by the following formula (3), and an electrophotographic photoreceptor is provided. [Chemical formula] (In formula (1), R , 32 , , , , , , , 41 ,

[0010] , 31 , , , , 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 of 1 or more and 3 or less, When n is 2 or 3, n Rf 1 may be the same as or different from each other.) [Chemical formula] (In formula (2), R 21 represents a hydrogen atom or a methyl group, Y represents a divalent organic group, Z represents a polymer moiety.) [Chemical formula] (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).) [Chemical formula] (In formula (4), R 41 represents an alkyl group having 1 to 4 carbon atoms.) [[ID=​​Furthermore, according to other aspects of the present disclosure, a process cartridge is provided that integrally supports the electrophotographic photoreceptor and at least one means selected from the group consisting of a charging means, a developing means, and a cleaning means, and is detachably attached to the body of an electrophotographic apparatus. Furthermore, according to other aspects of this disclosure, an electrophotographic apparatus is provided having the electrophotographic photoreceptor, as well as a charging means, an exposure means, a developing means, and a transfer means. Furthermore, according to other aspects of this disclosure, a method for manufacturing the electrophotographic photoreceptor is provided. [Effects of the Invention]

[0011] According to one aspect of this disclosure, an electrophotographic photoreceptor can be provided that exhibits excellent dispersibility of fluorine atom-containing resin particles in the surface layer and suppresses the occurrence of ghost images during repeated use. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing an example of the configuration of the electrophotographic photoreceptor in this disclosure. [Figure 2] This figure shows an example of a polishing machine using abrasive sheets. [Figure 3] This figure shows an example of a process cartridge equipped with the electrophotographic photoreceptor of this disclosure. [Figure 4] This figure shows an example of an electrophotographic apparatus equipped with the electrophotographic photoreceptor of this disclosure. [Figure 5] This is a schematic diagram showing the image signals used to evaluate ghosting. [Modes for carrying out the invention]

[0013] As a result of our investigations, we have found that by incorporating polymer A, which is obtained by polymerizing a composition containing fluorine atom-containing resin particles and the compound represented by formula (1), the compound represented by formula (2), and the compound represented by formula (3), into the surface layer of an electrophotographic photoreceptor, an electrophotographic photoreceptor can be obtained that exhibits excellent dispersibility of fluorine atom-containing resin particles in the surface layer and suppresses the generation of ghost images.

[0014] In other words, this disclosure is, Having a surface layer, The surface layer is Fluorine atom-containing resin particles, Binding material and, Polymer A and, It contains, The present invention provides an electrophotographic photoreceptor in which 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 (2), and a compound represented by the following formula (3). [ka] (In formula (1), R 11 This indicates a hydrogen atom or a methyl group. R 12 This represents a single bond, a methylene group, or an ethylene group. Rf 1 Each of these independently represents a perfluoroalkylene group having 1 to 5 carbon atoms, or a perfluoroalkylidene group having 1 to 5 carbon atoms. Rf 2 This 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 They may be the same or different from each other. [ka] (In formula (2), R 21 This indicates a hydrogen atom or a methyl group. Y represents a divalent organic group. Z indicates the polymerized site. [ka] (In formula (3), R 31 This indicates a hydrogen atom or a methyl group. R 32 (This represents a phenyl group, a cyano group, or a group represented by formula (4) below.) [ka] (In formula (4), R 41 (This represents an alkyl group with 1 to 4 carbon atoms.)

[0015] Furthermore, this disclosure relates to a method for manufacturing an electrophotographic photoreceptor having a surface layer, Fluorine atom-containing resin particles, A binder and at least one selected from the raw materials of the binder, Polymer A obtained by copolymerizing the compound represented by formula (1) above, the compound represented by formula (2) above, and the compound represented by formula (3) above, A step of preparing a coating solution for a surface layer containing, A step of forming the surface layer by forming a coating film of the surface layer coating liquid, and drying and / or curing the coating film, The present invention provides a method for manufacturing an electrophotographic photoreceptor having the following properties:

[0016] Polymer A may have structural units with acidic groups having a pKa of 3 or less, but it is preferable that it does not.

[0017] The pKa of an acidic group can be determined by measurement using known methods such as titration. Examples of acidic groups with a pKa below 3 include sulfonic acid groups (methanesulfonic acid: -2.6), phosphonic acid groups (first dissociation: 1.5), phosphate groups (first dissociation: 2.12), and alkyl fluoride carboxylic acid groups (e.g., trifluoroacetic acid: -0.25, difluoroacetic acid: 1.24, monofluoroacetic acid: 2.66).

[0018] Here, the inventors believe that the structure shown in formula (1) above acts as a dispersant for fluorine atom-containing resin particles in the process of preparing a coating solution for the surface layer of an electrophotographic photoreceptor.

[0019] The inventors speculate that the electrophotographic photoreceptor of this disclosure exhibits excellent dispersibility of fluorine atom-containing resin particles in the surface layer and excellent suppression of ghost image generation during repeated use, as follows.

[0020] Electrophotographic photoreceptors having a surface layer containing fluorine atom-containing resin particles and a dispersant tend to develop ghost images with repeated use. This is thought to be because electric charge tends to accumulate on the fluorine atom-containing resin particles contained in the surface layer.

[0021] Based on the inventors' investigations, -(CF2) n -When incorporating a polymer having structural units including chains into the surface layer, -(CF2) n -Chains- (CF2) n -We found that the presence of oxygen atoms between the chains suppresses the accumulation of charge in fluorine atom-containing resin particles. However, when a polymer copolymerized from macromonomers is used to impart dispersibility to the fluorine atom-containing resin particles, although the dispersibility of the fluorine atom-containing resin particles improves, the effect of suppressing the generation of ghost images is not sufficiently obtained. This is -(CF2) n -Chains- (CF2) n -It is presumed that the presence of oxygen atoms between the chains weakens the adhesion force to the fluorine atom-containing resin particles compared to when oxygen atoms are absent, and the macromonomer portions in the copolymer also begin to adhere to the fluorine atom-containing resin particles, thus weakening the adhesion to the fluorine atom-containing resin particles.

[0022] As a result of further investigation by the present inventors, it was found that by incorporating a copolymer obtained by further polymerizing the compound shown in formula (3) into the surface layer, charge accumulation is suppressed, and an electrophotographic photoreceptor in which the generation of ghost images is suppressed during repeated use can be obtained. The inventors speculate that this is the reason as follows: Because the side chains of the compound shown in formula (3) are short, spatial gaps are created within the polymer, allowing molecules to move more easily within the polymer and thus resolving steric constraints within the polymer. As a result, the -(CF2)n- chain, which has a high affinity for the fluorine atom-containing resin particles and is ultimately in an energetically stable state, adheres to the fluorine atom-containing resin particles.

[0023] Also, Rf in equation (1) 1 Rf is a perfluoroalkylene group or a perfluoroalkylidene group, and it has been found that the ghost suppression effect is obtained when the number of carbon atoms in each group is between 1 and 5. When the number of carbon atoms in the perfluoroalkylene group or perfluoroalkylidene group is greater than 5, it is hypothesized that the suppression effect of charge trapping via oxygen atoms cannot be obtained because charge accumulation occurs in the perfluoroalkylene group or perfluoroalkylidene group. In the above formula (1), Rf 2 The perfluoroalkyl group is one in number between 1 and 5 carbon atoms, and it has been found that the ghosting suppression effect is obtained when the number of carbon atoms is between 1 and 5. When the number of carbon atoms in the perfluoroalkyl group is greater than 5, it is hypothesized that the suppression effect of charge trapping via oxygen atoms is not obtained because charge accumulation occurs in the perfluoroalkyl group.

[0024] Also, R in formula (1) 12 It was found that by using a single bond, a methylene group, or an ethylene group, the ghosting suppression effect can be obtained. It is thought that the difference in surface energy between the structural unit shown in formula (1) and the fluorine atom-containing resin particles becomes smaller, making it easier for the unit to adhere to the fluorine atom-containing resin particles and suppressing the accumulation of charge on the fluorine atom-containing resin particles.

[0025] <Fluorine atom-containing resin particles> The surface layer of the electrophotographic photoreceptor of this disclosure contains fluorine atom-containing resin particles. The content of 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 an electrophotographic photoreceptor is the surface layer, the content of fluorine atom-containing resin particles is preferably 20% to 40% by mass, and more preferably 25% to 35% by mass, relative to the protective layer.

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

[0028] When the photosensitive layer of an electrophotographic photoreceptor is a single-layer photosensitive layer and the photosensitive layer is the surface layer, the content of 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 this disclosure include: polytetrafluoroethylene resin, polychlorotrifluoroethylene resin, polytetrafluoroethylene propylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, or 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, polytetrafluoroethylene resin is more preferable for the fluorine atom-containing resin particles.

[0030] In cross-sectional observation of the surface layer of fluorine atom-containing resin particles using a scanning electron microscope, it is preferable that the arithmetic mean of the major axis of the primary particles (average primary particle size) measured from the secondary electron image obtained by the scanning electron microscope is between 150 nm and 300 nm, from the viewpoint of improving dispersibility and suppressing the generation of ghost images. Furthermore, it is preferable that the average primary particle size of the fluorine atom-containing resin particles is between 180 nm and 250 nm.

[0031] It is preferable that the fluorine atom-containing resin particles have an average roundness (average roundness) of 0.75 or higher, calculated from the area and circumference of primary particles measured from secondary electron images obtained by scanning electron microscopy.

[0032] To bring the measured values ​​of the average primary particle size and average roundness of the fluorine atom-containing resin particles contained in the surface layer of the electrophotographic photoreceptor of this disclosure within the above range, fluorine atom-containing resin particles can be used such that the average primary particle size and average roundness values ​​measured and calculated by the following method fall within the above range.

[0033] (Measurement method for average primary particle size and average roundness) In other words, in the embodiments of this disclosure, the average particle size and average roundness of the fluorine atom-containing resin particles to be incorporated into the surface layer of the electrophotographic photoreceptor were measured using a field emission scanning electron microscope (FE-SEM) as follows. Fluorine atom-containing resin particles were attached to a commercially available carbon conductive tape, and fluorine atom-containing resin particles not attached to the conductive tape were removed with compressed air, followed by platinum deposition. The deposited fluorine atom-containing resin particles were observed using a Hitachi High-Technologies Corporation FE-SEM (S-4700). The measurement conditions for the FE-SEM were as follows. Acceleration voltage: 2kV WD: 5mm Magnification: 20,000 times Pixel count: 1280 pixels vertically, 960 pixels horizontally (size of each pixel: 5nm) The Ferret diameter of 100 particles was determined from the obtained images using ImageJ (open-source software from the National Institutes of Health (NIH)), and the average value was calculated to determine the average particle size. Similarly, the area and perimeter were determined, the roundness was calculated using the following formula (II), and the average value was calculated and defined as the average roundness. Roundness = 4 × π × (area) ÷ (perimeter squared) Equation (II) The fluorine atom-containing resin particles of this disclosure may be used alone or in combination of two or more types.

[0034] <Binding material> The surface layer of the electrophotographic photoreceptor of this disclosure contains a binder material. When the protective layer of an 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 for the binder material. Examples of raw materials for the binder material include monomers having polymerizable functional groups. Examples of polymerizable functional groups include isocyanate groups, blocked isocyanate groups, methylol groups, alkylated methylol groups, epoxy groups, metal alkoxide groups, hydroxyl groups, amino groups, carboxyl groups, thiol groups, carboxylic acid anhydride groups, and groups containing carbon-carbon double bonds. Examples of groups containing carbon-carbon double bonds include acryloyl groups and methacryloyl groups. As monomers having charge transport ability, monomers represented by formulas (CT-1) or (CT-2) described later are preferred. When the photosensitive layer of an electrophotographic photoreceptor is a multilayer photosensitive layer and the charge transport layer is the surface layer, the binder material is a thermoplastic resin. Examples of thermoplastic resins include polyester resin, polycarbonate resin, acrylic resin, and polystyrene resin. Among these, polycarbonate resin and polyester resin are preferred. Among polyester resins, polyarylate resin is particularly preferred. When the photosensitive layer of an electrophotographic photoreceptor is a single-layer photosensitive layer and the photosensitive layer is the surface layer, the binder material is a thermoplastic resin. Examples of thermoplastic resins include polyester resin, polycarbonate resin, acrylic resin, and polystyrene resin. Among these, polycarbonate resin and polyester resin are preferred. Among polyester resins, polyarylate resin is particularly preferred.

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

[0036] In equation (1) above, R 11 R is a hydrogen atom or a methyl group. 12 R is either a single bond, a methylene group, or an ethylene group. 12 If the alkylene has a high number of carbon atoms, the surface energy difference between polymer A and the fluorine atom-containing resin particles becomes large, making it difficult for them to adhere to each other sufficiently, and resulting in insufficient dispersibility. Furthermore, from the viewpoint of dispersibility, R 12 It is more preferable that it be a methylene group. n reduction Rf 1 These are, independently, perfluoroalkylene groups having 1 to 5 carbon atoms or perfluoroalkylidene groups having 1 to 5 carbon atoms. Rf 2 Rf is a perfluoroalkyl group having 1 to 5 carbon atoms. 1 , and Rf 2 If the carbon number is increased to 6 or more, the accumulation of charge in the fluorine atom-containing resin particles cannot be sufficiently suppressed, and the occurrence of ghost images cannot be sufficiently suppressed when the electrophotographic photoreceptor is repeatedly used.

[0037] Furthermore, in equation (1) above, n Rf 1 The number of carbon atoms it has and Rf 2 It is preferable that the total number of carbon atoms in the material is between 5 and 8.

[0038] Furthermore, in formula (1) above, Rf 1 Rf is a perfluoroalkylene group having 2 or 3 carbon atoms, or a perfluoroalkylidene group having 2 or 3 carbon atoms. 2 It is preferable that it is a perfluoroalkyl group having 2 or 3 carbon atoms. n is an integer between 1 and 3, and when n is 2 or greater, there are n Rf 1 These may be the same or different. Furthermore, it is more preferable that n in formula (1) is 1 or 2.

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

[0040] [ka]

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

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

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

[0044] The end of the polymer moiety represented by Z in formula (2) may have an end-terminating agent or may have a hydrogen atom.

[0045] The compound represented by formula (2) is preferably the compound represented by formula (5) below. [ka] In equation (5) above, Y A1 represents an unsubstituted alkylene group, Y B This represents an unsubstituted alkylene group, a halogen-substituted alkylene group, a hydroxyl-substituted alkylene group, an ester bond (-COO-), an amide bond (-NHCO-), or a urethane bond (-NHCOO-), or a divalent linking group that can be derived by combining one or more of these groups and bonds with -O- or -S-, or a single bond, Z A R represents the structure represented by formula (2A), a cyano group, or a phenyl group. 51 , R 52 represents a hydrogen atom or a methyl group, and m represents an integer between 25 and 150.

[0046] In formula (5), Y B If it shows an ester bond, -Y A1 -Y B -CH2- is -Y A1 -CO-O-CH2- and -Y A1 Either -O-CO-CH2- is acceptable, preferably -Y A1 It is -CO-O-CH2-. Also, in equation (5), Y B If it shows an amide bond, -Y A1 -Y B -CH2- is -Y A1 -NH-CO-CH2- and -Y A1 Either -CO-NH-CH2- is acceptable, preferably -Y A1It is -NH-CO-CH2-. Also, in equation (5), Y B If it is a urethane bond, -Y A1 -Y B -CH2- is -Y A1 -NH-CO-O-CH2- and -Y A1 Either -O-CO-NH-CH2- is acceptable, preferably -Y A1 It is -NH-CO-O-CH2-.

[0047] -Y in equation (5) above A1 -Y B - is, -Y A1 -(Y A2 ) b -(Y A3 ) c -(Y A4 ) d -(Y A5 ) e -(Y A6 ) f It is preferable that the structure be as shown by -. Y A1 This shows an unsubstituted alkylene group, Y A2 This represents a methylene group substituted with at least one selected from the group consisting of hydroxyl groups and halogen atoms, Y A3 This shows an unsubstituted alkylene group, Y A4 Y represents an ester bond, amide bond, or urethane bond. A5 This shows an unsubstituted alkylene group, 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 alkylene groups include methylene, ethylene, propylene, butylene, pentylene, and hexylene groups. Among these, methylene, ethylene, and propylene groups are preferred.

[0048] Further specific examples of compounds represented by formula (5) include the following compounds. A particularly preferred example is 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 this disclosure contains polymer A of a composition comprising a compound represented by the following formula (3). [ka] In equation (3) above, R 31 R 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 (This represents an alkyl group with 1 to 4 carbon atoms.)

[0050] Furthermore, from the perspective of suppressing the occurrence of ghost images, R 41 It is more preferable that it be a methyl group.

[0051] Further specific examples of compounds represented by formula (3) include the following compounds. Particularly preferred examples include compounds represented by (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. Polymer A can have structural units represented by the following formulas (101), (201), and (301).

Chemical formula

Chemical formula

Chemical formula

Chemical formula

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

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

[0056] Of the polymer A contained in the surface layer of the electrophotographic photoreceptor of this disclosure, the structural units derived from the compound represented by formula (1) are preferably 5 mol% to 95 mol%, more preferably 50 mol% to 95 mol%, and even more preferably 70 mol% to 90 mol%, relative to the total content of all structural units of polymer A, from the viewpoint of improving the dispersibility of fluorine atom-containing resin particles.

[0057] In the polymer A contained in the surface layer of the electrophotographic photoreceptor of this disclosure, it is preferable that the structural units derived from the compound represented by formula (1) are 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 structural units derived from the compound represented by formula (1) to 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] The weight-average molecular weight of polymer A contained in the surface layer of the electrophotographic photoreceptor of this disclosure is preferably 16,000 to 100,000, from the viewpoint of improving the dispersibility of fluorine atom-containing resin particles and suppressing the occurrence of ghost images. Furthermore, the weight-average molecular weight of polymer A in the composition containing (1), (2), and (3) is more preferably 18,000 to 80,000.

[0060] The weight-average molecular weight of polymer A can be measured and calculated using the following method. (Weight-average molecular weight measurement by GPC) The weight-average molecular weight relating to this 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. Then, the resulting solution is filtered through a solvent-resistant membrane filter, "Maeshori Disc" (manufactured by Tosoh Corporation), with a pore diameter of 0.2 μm, to obtain the sample solution. The sample solution is adjusted so that the concentration of components soluble in THF is approximately 0.8% by mass. This sample solution is then used for measurement under the following conditions. • Equipment: HLC8120 GPC (Detector: RI) (Manufactured by Tosoh Corporation) • Columns: Shodex KF-801, 802, 803, 804, 805, 806, 807 (7 columns, manufactured by Showa Denko) • Eluent: Tetrahydrofuran (THF) ·Flow rate: 1.0ml / min Oven temperature: 40.0℃ • Sample injection volume: 0.10 ml For calculating the molecular weight of the sample, a molecular weight calibration curve prepared using standard polystyrene resin (for example, "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, and more preferably 4% by mass or more and 8% by mass or less, from the viewpoint of improving dispersibility and suppressing the generation of ghost images.

[0062] <Electrophotographic photoconductor> Figure 1 shows an example of the layer structure of the electrophotographic photoreceptor of this disclosure. In Figure 1, a base 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 composed of a laminated photosensitive layer having a charge generation layer and a charge transport layer, or it may be composed of a single-layer photosensitive layer containing a charge generation material and a charge transport material.

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

[0064] A method for manufacturing the electrophotographic photoreceptor according to this disclosure includes preparing coating solutions for each layer, applying the desired layers in order, and drying them. Examples of coating methods include immersion coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, and ring coating. Among these, immersion coating is preferred from the viewpoint of efficiency and productivity.

[0065] The configuration of the electrophotographic photoreceptor described herein will be explained below. <Support> The electrophotographic photoreceptor of this disclosure preferably has a support. The support of the electrophotographic photoreceptor is preferably conductive (conductive support). The shape of the support can be cylindrical, belt-shaped, or sheet-shaped. Among these, a cylindrical support is preferred. The surface of the support may also be subjected to electrochemical treatments such as anodizing, blasting, or cutting. Suitable materials for the support include metal, resin, and glass. Examples of metals include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. Among these, an aluminum support made of aluminum is preferred. Furthermore, it is preferable to impart conductivity to resins and glass by processing them, such as by mixing or coating them with conductive materials.

[0066] <Conductive layer> A conductive layer may be provided on the support. By providing a conductive layer, scratches and irregularities on the surface of the support can be concealed, and light reflection on the surface of the support can be controlled. The conductive layer preferably contains conductive particles and a resin.

[0067] Examples of materials for 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, and bismuth oxide. Examples of metals include aluminum, nickel, iron, nichrome, copper, zinc, and silver. Among these, it is preferable to use metal oxide particles as conductive particles, and it is more preferable to use titanium oxide particles, tin oxide particles, or zinc oxide particles. When using metal oxide particles as conductive particles, the surface of the metal oxide particles may be treated with a silane coupling agent or the like, or the metal oxide particles may be doped with elements such as phosphorus or aluminum, or their oxides. Furthermore, the conductive particles may have a laminated structure comprising core material particles and a coating layer covering those particles. Examples of core material particles include titanium oxide particles, barium sulfate particles, and zinc oxide particles. Examples of coating layer particles include metal oxide particles such as tin oxide. Furthermore, when metal oxide particles are used as conductive particles, their volume-average particle size is preferably 1 nm or more and 500 nm or less, and more preferably 3 nm or more and 400 nm or less.

[0068] Examples of resins include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenolic resin, and alkyd resin. Furthermore, the conductive layer may further contain silicone oil, resin particles, a concealing agent such as titanium dioxide, etc.

[0069] A conductive layer can be formed by preparing a coating solution for a conductive layer containing the above-mentioned materials and solvents, forming this coating film on a support, and drying it. Examples of solvents used in the coating solution for a conductive layer include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Methods for dispersing conductive particles in the coating solution for a conductive layer include using a paint shaker, sand mill, ball mill, or liquid impaction 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] <Underlayer> In this disclosure, an undercoat layer may be provided on the support or conductive layer. Providing an undercoat layer enhances the interlayer adhesion function and imparts a charge injection blocking function.

[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 polymerizable functional groups. Examples of resins include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenolic resin, polyvinylphenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, polyamide resin, polyamic acid resin, polyimide resin, polyamide-imide resin, and cellulose resin. Polymerizable functional groups found in monomers possessing polymerizable functional groups include isocyanate groups, blocked isocyanate groups, methylol groups, alkylated methylol groups, epoxy groups, metal alkoxide groups, hydroxyl groups, amino groups, carboxyl groups, thiol groups, carboxylic acid anhydride groups, and carbon-carbon double bond groups.

[0073] Furthermore, the undercoat layer may further contain electron transport materials, metal oxide particles, metal particles, conductive polymers, etc., for the purpose of improving electrical properties. Among these, electron transport materials and metal oxide particles are preferred. Examples of electron transport materials include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, aryl halides, silole compounds, and boron-containing compounds. An electron transport material having polymerizable functional groups may be used as the electron transport material, and a base layer may be formed as a cured film by copolymerizing it with the above-mentioned monomers having polymerizable functional groups. Examples of metal oxide particles include 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 gold, silver, and aluminum. The metal oxide particles contained in the undercoat may be surface-treated using a surface treatment agent such as a silane coupling agent before use.

[0074] Common methods are used for surface treatment of metal oxide particles. Examples include dry and wet methods. The dry method involves adding an aqueous alcohol solution, an organic solvent solution, or an aqueous solution containing a surface treatment agent to metal oxide particles while stirring them in a high-speed mixer such as a Henschel mixer, then uniformly dispersing them and drying them. In the wet method, metal oxide particles and a surface treatment agent are stirred in a solvent or dispersed using a sand mill with glass beads or the like. 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 including metal particles like aluminum particles, conductive material particles like carbon black, charge transport materials, metal chelate compounds, and organometallic compounds.

[0076] The undercoat layer can be formed by preparing an undercoat coating solution containing the above-mentioned materials and solvents, forming this coating film on a support or conductive layer, and then drying and / or curing it.

[0077] Examples of solvents used in the coating liquid for the undercoat include organic solvents such as alcohols, sulfoxides, ketones, ethers, esters, aliphatic halogenated hydrocarbons, and aromatic compounds. In this disclosure, it is preferable to use alcohol-based or ketone-based solvents.

[0078] Dispersion methods for preparing coating liquids for the undercoat include methods using homogenizers, ultrasonic dispersers, ball mills, sand mills, roll mills, vibratory mills, attritors, and liquid impact type high-speed dispersers.

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

[0080] <Photosensitive layer> The photosensitive layers of electrophotographic photoreceptors are mainly classified into (1) multilayer photosensitive layers and (2) single-layer photosensitive layers. (1) A multilayer photosensitive layer is a photosensitive layer having a charge generating layer containing a charge generating material and a charge transport layer containing a charge transport material. (2) A single-layer photosensitive layer is a photosensitive layer containing both a charge generating material and a charge transport material.

[0081] (1) Stacked photosensitive layer The stacked photosensitive layer comprises a charge generation layer and a charge transport layer.

[0082] (1-1) Charge generation layer The charge generation layer preferably contains a charge generation 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% to 85% by mass, and more preferably 60% to 80% by mass, relative to the total mass of the charge generating layer.

[0084] Examples of resins include polyester resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl butyral resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenolic resin, polyvinyl alcohol resin, cellulose resin, polystyrene resin, polyvinyl acetate resin, and polyvinyl chloride resin. Among these, polyvinyl butyral resin is more preferred.

[0085] Furthermore, the charge generation layer may contain additives such as antioxidants and ultraviolet absorbers. Specifically, these include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.

[0086] The charge generation layer can be formed by preparing a coating solution for the charge generation layer containing the above-mentioned materials and solvents, forming this coating film on a lower layer such as an undercoat layer, and drying it. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0087] The average thickness of the charge generation layer is preferably 0.1 μm or more and 1 μm or less, and more preferably 0.15 μm or more and 0.4 μm or less.

[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 substances. Among these, triarylamine compounds and benzidine compounds are preferred. The content of the charge transport material in the charge transport layer is preferably 25% to 70% by mass, and more preferably 30% to 55% by mass, relative to the total mass of the charge transport layer.

[0090] Examples of resins include polyester resin, polycarbonate resin, acrylic resin, and polystyrene resin. Among these, polycarbonate resin and polyester resin are preferred. Polyarylate resin is particularly preferred among polyester resins. 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] Furthermore, if the photosensitive layer is a laminated photosensitive layer and no protective layer is provided as described later, the charge transport layer becomes the surface layer. In this case, the charge transport layer contains fluorine atom-containing resin particles, a binder material, and polymer A of a composition comprising the compound represented by formula (1), the compound represented by formula (2), and the compound represented by formula (3).

[0092] Furthermore, the charge transport layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, and leveling agents. Specifically, examples 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 solvents, forming this coating film on the charge generating 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 or aromatic hydrocarbon-based solvents are preferred.

[0094] The average thickness of the charge transport layer is preferably 5 μm to 50 μm, more preferably 8 μm to 40 μm, and particularly preferably 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 a photosensitive layer containing a charge generating substance, a charge transporting substance, a resin, and a solvent, forming this coating film on a lower layer such as an undercoat layer, and drying it. The charge generating substance, charge transporting substance, and resin are the same as the examples of materials in "(1) Multilayer Photosensitive Layer" above. If the photosensitive layer is a single-layer photosensitive layer and no protective layer is provided as described later, the photosensitive layer becomes the surface layer.

[0096] <Protective layer> In this invention, a protective layer may be provided on the photosensitive layer. Providing a protective layer 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 reactions include thermal polymerization, photopolymerization, and radiation polymerization. Examples of polymerizable functional groups in monomers containing polymerizable functional groups include isocyanate groups, blocked isocyanate groups, methylol groups, alkylated methylol groups, epoxy groups, metal alkoxide groups, hydroxyl groups, amino groups, carboxyl groups, thiol groups, carboxylic acid anhydride groups, and groups containing carbon-carbon double bonds. Examples of groups containing carbon-carbon double bonds include acryloyl groups and methacryloyl groups. Monomers with charge transport ability may be used as monomers containing polymerizable functional groups.

[0098] As monomers having charge transport ability, monomers represented by the following formulas (CT-1) or (CT-2) are preferred. [ka] In the above formula (CT-1), Ar 11 ~Ar 13 Each of these is independently a substituted aryl group or an unsubstituted aryl group. The substituents that the substituted aryl group may have are alkyl groups having 1 to 6 carbon atoms, or monovalent functional groups represented by any 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 of the following formulas (P-1) to (P-3). [ka] In the above formula (CT-2), Ar 21 ~Ar 24 These are, independently, a substituted aryl group or an unsubstituted aryl group, AR 25This is a substituted aryl group or an unsubstituted aryl group. The substituents that the substituted aryl group may have are alkyl groups having 1 to 6 carbon atoms, or monovalent functional groups represented by the following formulas (P-1) to (P-3). The substituents that the substituted aryl group may have are alkyl groups having 1 to 6 carbon atoms, or monovalent functional groups 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 above equation (P-1), Z 11 X is a single bond or an alkylene group having 1 to 6 carbon atoms. 11 This is a hydrogen atom or a methyl group. [ka] In the above equation (P-2), Z 21 This is a single bond or an alkylene group having 1 to 6 carbon atoms. [ka] In the above equation (P-3), Z 31 This is a single bond or an alkylene group having 1 to 6 carbon atoms.

[0100] When a protective layer is provided, the protective layer becomes the surface layer of the electrophotographic photoreceptor. In this case, the protective layer contains fluorine atom-containing resin particles, a binder, and polymer A.

[0101] The protective layer may contain additives such as antioxidants, UV absorbers, plasticizers, and leveling agents. Specifically, these 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 protective coating solution containing the above-mentioned materials and solvents, 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 from the viewpoint of not dissolving the underlying photosensitive layer.

[0103] The average thickness of the protective layer is preferably 0.5 μm to 10 μm, and more preferably 1 μm to 7 μm.

[0104] <Surface treatment of electrophotographic photoreceptors> In this disclosure, the surface of the electrophotographic photoreceptor may be processed. By processing the surface, the behavior of the cleaning means (cleaning blade) that comes into contact with the electrophotographic photoreceptor can be made more stable. Methods of surface processing include pressing a mold having protrusions onto the surface of the electrophotographic photoreceptor to transfer the shape, creating uneven surfaces by mechanical polishing, or roughening the surface by impacting powder onto the surface of the electrophotographic photoreceptor. In this way, by providing recesses or protrusions on the surface layer of the electrophotographic photoreceptor, the behavior of the cleaning means that comes into contact with the electrophotographic photoreceptor can be made more stable.

[0105] The recesses or protrusions may be formed over the entire surface of the electrophotographic photoreceptor, or on a portion of the surface of the electrophotographic photoreceptor. If the recesses or protrusions are formed on a portion of the surface of the electrophotographic photoreceptor, 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 a recess, a mold having a convex portion corresponding to the recess is pressed against the surface of the electrophotographic photoreceptor, and the shape is transferred, thereby forming a recess on the surface of the electrophotographic photoreceptor.

[0107] <Abrasive tools used for mechanical polishing> Mechanical polishing can be performed using known methods. Generally, a polishing tool is brought into contact with an electrophotographic photoreceptor, and one or both of the tools are moved relative to each other to polish the surface of the electrophotographic photoreceptor. The polishing tool is a polishing member having a layer on a base material in which abrasive particles are dispersed in a binder resin.

[0108] Examples of abrasive particles include aluminum oxide, chromium oxide, diamond, iron oxide, cerium oxide, corundum, silica, silicon nitride, boron nitride, molybdenum carbide, silicon carbide, tungsten carbide, titanium carbide, and silicon oxide. The particle size of the abrasive particles is preferably 0.01 to 50 μm, and more preferably 1 to 15 μm. If the particle size of the abrasive particles is too small, the polishing power will be weak, and it will be difficult to increase the F / C ratio of the outermost surface of the electrophotographic photoreceptor. These abrasive particles can be used individually or in mixtures of two or more types. When mixing two or more types, the material and particle size may be different or the same.

[0109] As the binder resin for dispersing abrasive particles used in polishing tools, known thermoplastic resins, thermosetting resins, reactive resins, electron beam curing resins, ultraviolet curing resins, visible light curing resins, and antifungal resins can be used. Examples of thermoplastic resins include vinyl chloride resin, polyamide resin, polyester resin, polycarbonate resin, amino resin, styrene-butadiene copolymer, urethane elastomer, and polyamide-silicone resin. Examples of thermosetting resins include phenolic resin, phenoxy resin, epoxy resin, polyurethane resin, polyester resin, silicone resin, melamine resin, and alkyd resin. An isocyanate-based curing agent may also be added to the thermoplastic resin.

[0110] The thickness of the layer formed by dispersing abrasive grains in the binder resin of the polishing tool is preferably 1 to 100 μm. If the thickness is too thick, unevenness in thickness is likely to occur, resulting in uneven surface roughness of the workpiece. On the other hand, if the thickness is too thin, the abrasive grains are more likely to fall off.

[0111] The shape of the base material of the polishing tool is not particularly limited. In the embodiments of this disclosure, a sheet-like base material was used to efficiently polish a cylindrical electrophotographic photoreceptor, but other shapes may also be used. (Hereafter, the polishing tool of this disclosure will also be referred to as a polishing sheet.) The material of the base material of the polishing tool is also not particularly limited. For example, the material of the sheet-like base material may be paper, woven fabric, nonwoven fabric, or plastic film.

[0112] The polishing tool can be obtained by coating a substrate with a paint mixture in which the above-mentioned abrasive grains, binder resin, and solvent capable of dissolving the binder resin are mixed and dispersed, and then drying the mixture.

[0113] <Polishing equipment> An example of the polishing apparatus for electrophotographic photoreceptors described herein is shown in Figure 2. Figure 2 shows an apparatus for polishing a cylindrical electrophotographic photoreceptor using a polishing sheet. In Figure 2, the polishing sheet 2-1 is wound around a hollow shaft 2-6, and a motor (not shown) is positioned so that tension is applied to the polishing sheet 2-1 in the opposite direction to the direction in which the polishing sheet 2-1 is fed to the shaft 2-6. The polishing sheet 2-1 is fed in the direction of the arrow, passes through guide rollers 2-2a and 2-2b to a backup roller 2-3, and after polishing, the polishing sheet 2-1 is wound onto a winding means 2-5 by a motor (not shown) via guide rollers 2-2c and 2-2d. Polishing is performed by constantly pressing the polishing sheet 2-1 against the workpiece (electrophotographic photoreceptor before polishing) 2-4. Since the polishing sheet 2-1 is often insulating, it is preferable to use a material that is grounded or conductive at the contact points of the polishing 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 result in deep scratches on the surface of the workpiece 2-4.

[0115] The workpiece 2-4 is placed at a position facing the backup roller 2-3 through the polishing sheet 2-1. From the perspective of improving the surface roughness uniformity of the workpiece 2-4, the backup roller 2-3 is preferably an elastic body. At this time, the workpiece 2-4 and the backup roller 2-3 are pressed against each other through the polishing sheet 2-1 at a desired set 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 the direction in which the polishing sheet 2-1 is fed, or may be opposite. Also, the rotation direction may be changed during polishing.

[0116] The pressing pressure of the backup roller 2-3 against the workpiece 2-4 depends on the hardness of the backup roller 2-3 and the polishing time, but is preferably 0.005 to 15 N / m. 2 is preferred.

[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 substrate, etc.

[0118] <Measurement of 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 Coater SE3500 type surface roughness measuring instrument manufactured by Kosaka Laboratory Ltd. A non-contact three-dimensional surface measuring machine Micro Map 557N manufactured by Hishikawa System Co., Ltd. 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 surface roughness indicators, 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, regarding the range of the 5 mm square section of the electrophotographic photoreceptor cut out as a specimen for the X-ray photoelectron spectroscopy described later, Rmax is measured in advance. The measurement is performed arbitrarily at three locations within the 5 mm square range, and the average value is adopted as the polishing depth L (μm).

[0119] <Process cartridges, electrophotographic equipment> The electrophotographic photoreceptor of this disclosure may be a process cartridge or one of the components of an electrophotographic apparatus. The process cartridge integrally supports the electrophotographic photoreceptor described herein 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 attached to the main body of the electrophotographic apparatus. The electrophotographic apparatus also includes the electrophotographic photoreceptor, charging means, exposure means, developing means, and transfer means described herein.

[0120] Figure 3 shows a process cartridge configuration equipped with the electrophotographic photoreceptor of this disclosure, and Figure 4 shows an example of a schematic configuration of an electrophotographic apparatus having the process cartridge of Figure 3.

[0121] In Figure 3, the cylindrical electrophotographic photoreceptor 1 is driven to rotate at a predetermined peripheral speed in the direction of the arrow. The peripheral surface of the rotating electrophotographic photoreceptor 1 is uniformly charged to a predetermined positive or negative potential by the charging means 2. Next, the charged peripheral surface of the electrophotographic photoreceptor 1 receives exposure light (image exposure light) 3 output from an exposure means (not shown), such as slit exposure or laser beam scanning exposure. In this way, an electrostatic latent image corresponding to the desired image is sequentially formed on the peripheral surface of the electrophotographic photoreceptor 1. The voltage applied to the charging means (charging roller, etc.) 2 may be either a voltage with an AC component superimposed on a DC component, or a voltage with only a DC component.

[0122] The electrostatic latent image formed on the circumferential surface of the electrophotographic photoreceptor 1 is developed by the toner contained in the developer of the developing means 4 to form a toner image. Next, the toner image formed and supported on the circumferential surface of the electrophotographic photoreceptor 1 is sequentially transferred to the transfer material (paper, intermediate transfer material, etc.) 6 by the transfer bias from the transfer means (transfer roller, etc.) 5. The transfer material 6 is fed in synchronization with the rotation of the electrophotographic photoreceptor 1.

[0123] After toner image transfer, the surface of the electrophotographic photoreceptor 1 is treated to remove static electricity by pre-exposure light 7 from a pre-exposure means (not shown), and then cleaned by a cleaning means 8 to remove any remaining toner. The electrophotographic photoreceptor 1 is then repeatedly used for image formation. The pre-exposure means may be performed before or after the cleaning process, and is not necessarily required.

[0124] The electrophotographic photoreceptor 1 may be mounted in an electrophotographic device such as a copier or a laser beam printer. Alternatively, a process cartridge 9 may be constructed by housing and supporting multiple components, such as the electrophotographic photoreceptor 1, charging means 2, developing means 4, and cleaning means 8, in a container, and making it detachable from the electrophotographic device body. In Figure 3, the electrophotographic photoreceptor 1, charging means 2, developing means 4, and cleaning means 8 are supported as a single unit, forming a process cartridge 9 that is detachable from the electrophotographic device body.

[0125] Figure 4 shows an example of the configuration of the electrophotographic apparatus of this disclosure. Process cartridges 17 for yellow, 18 for magenta, 19 for cyan, and 20 for black, corresponding to yellow, magenta, cyan, and black respectively, are arranged side by side along the intermediate transfer body 10. The diameter, constituent materials, developer, charging method, and other means of the electrophotographic photoreceptor do not necessarily have 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, the transfer paper 11 is fed from the paper tray 13 by the paper feed path 12 and is fed to the secondary transfer means 14 in time with the rotation of the intermediate transfer body 10. The toner image on the intermediate transfer body 10 is transferred to the transfer paper 11 by the transfer bias from the secondary transfer means 14. The toner image transferred onto the transfer paper 11 is transported along the paper feed path 12, fixed onto the transfer paper 11 by the fixing means 15, and then discharged from the paper discharge unit 16. [Examples]

[0127] The present disclosure will be described in further detail below using examples and comparative examples, but will not be limited thereto. In the following descriptions of examples, "parts" refers to mass unless otherwise specified.

[0128] <Synthesis of Polymer A> Polymers of compositions containing (1), (2), and (3) in this disclosure (hereinafter also referred to as "graft copolymers") were synthesized as described below. The acrylate compounds and macromonomer compounds used in the following synthesis examples can be produced, for example, by referring to Japanese Patent Application Publication No. 2009-104145.

[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 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) 0.874 parts of (manufactured by Chemical Co., Ltd.) and 676 parts of n-butyl acetate were mixed for 30 minutes at 20°C under a nitrogen atmosphere in a glass flask equipped with a stirrer, reflux condenser, nitrogen gas inlet tube, constant temperature bath, and thermometer. The reaction was then heated to 85-90°C and allowed to proceed for 5 hours. The reaction was stopped by ice cooling, and 3000 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 under reduced pressure below 1325 PA for 3 hours to obtain graft copolymer 1. [ka]

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

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

[0132] The obtained graft copolymers 1-39 were subjected to GPC measurement using the method described above, and their weight-average molecular weight was calculated. The results are shown in Table 2.

[0133] [Table 2]

[0134] <Fabrication of electrophotographic photoreceptors> [Example 1-1] (Support 1) As a support (conductive support), a cylindrical aluminum cylinder (JIS-A3003, aluminum alloy, outer diameter 30.6 mm, length 370 mm, wall thickness 1 mm) that had been machined was used. Ultrasonic cleaning was performed in a cleaning solution containing detergent (product name: Chemicol CT, manufactured by Tokiwa Chemical Co., Ltd.) in pure water, followed by rinsing off the cleaning solution, and then further ultrasonic cleaning in pure water to degrease it, and this was used as support 1.

[0135] (Bottom layer 1) Zinc oxide particles (specific surface area: 19 m²) 2 / g, powder resistance: 4.7×10 6100 parts of (Ω·cm) were mixed with 500 parts of toluene and stirred. 0.8 parts of a silane coupling agent (compound name: N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, trade name: KBM602, manufactured by Shin-Etsu Chemical Co., Ltd.) were added, and the mixture was stirred for 6 hours. Subsequently, the toluene was removed by distillation under reduced pressure, and the mixture was heated and dried 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.) and 15 parts of blocked isocyanate (trade name: Duranate TPA-B80E, non-volatile content 80% by mass, manufactured by Asahi Kasei Chemicals Corporation) 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 for 3 hours at a 23±3°C atmosphere using a sand mill apparatus with glass beads with a diameter of 0.8 mm. After dispersion treatment, 0.01 parts of silicone oil (product name: SH28PA, manufactured by Toray Dow Corning Co., Ltd. (formerly Toray Dow Corning Silicone Co., Ltd.)) and 5.6 parts of cross-linked polymethyl methacrylate (PMMA) particles (product name: Techpolymer SSX-103, manufactured by Sekisui Chemical Co., Ltd., average primary particle size: 3 μm) were added and stirred to prepare a coating solution for the undercoat layer.

[0137] The obtained undercoating solution was applied to the support by immersion to form a coating film, and the coating film was dried at 160°C for 30 minutes to form an undercoat 1 with a thickness of 18 μm.

[0138] (Charge generation layer 1) Four parts of hydroxygallium phthalocyanine crystals (charge-generating material) in a crystalline form having strong peaks at 7.4° and 28.1° of the Bragg angle 2θ±0.2° in CuKα characteristic X-ray diffraction, and 0.04 parts of the compound represented by the following formula (E) were added to a solution prepared by dissolving 2 parts of polyvinyl butyral (trade name: S-Rec BX-1, manufactured by Sekisui Chemical Co., Ltd.) in 100 parts of cyclohexanone. Subsequently, the mixture was dispersed for 1 hour in a sand mill using 1 mm diameter glass beads under an atmosphere of 23±3°C. After dispersion, 100 parts of ethyl acetate were added to prepare a coating solution for the charge-generating layer. This charge generation layer coating solution was applied to the undercoat layer 1 by immersion, and the resulting coating film was dried at 90°C for 10 minutes to form a charge generation layer 1 with a thickness of 0.15 μm. [ka]

[0139] (Charge transport layer 1) A coating solution for the charge transport layer was prepared by dissolving 60 parts of the compound represented by formula (F) below, 30 parts of the compound represented by formula (G) below, 10 parts of the compound represented by formula (H) below, 100 parts of bisphenol Z type polycarbonate resin (product name: Yupiron Z400, manufactured by Mitsubishi Engineering Plastics Corporation), and 0.2 parts of polycarbonate having the structural unit represented by formula (I) below (viscosity-average molecular weight Mv: 20000) in a mixed solvent of 272 parts o-xylene, 256 parts methyl benzoate, and 272 parts dimethoxymethane. This charge transport layer coating solution was applied to the above-mentioned charge generating layer 1 by immersion 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 with 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 graft copolymer 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 Inc.) and 100 parts of 1-propanol. 40 parts of polytetrafluoroethylene resin particles (average primary particle size 210 nm, average roundness 0.85) were added to the obtained dispersant solution. Then, it was passed through a high-pressure disperser (trade name: Microfluidizer M-110EH, manufactured by Microfluidics Corp., USA) to obtain a polytetrafluoroethylene resin particle dispersion. 75.4 parts of a hole-transporting 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 to the obtained polytetrafluoroethylene resin particle dispersion. Then, filtration was performed with a polytetrafluoroethylene filter (trade name: PF-040, manufactured by Advantec Toyo Co., Ltd.) to prepare a polytetrafluoroethylene resin particle dispersion (coating solution for the protective layer).

Chemical formula

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

[0142] <Surface processing of the electrophotographic photoreceptor> (Polishing of the electrophotographic photoreceptor before surface polishing) The surface of the electrophotographic photoreceptor before forming the surface shape was polished. The polishing was performed using the above-described polishing apparatus under the following conditions. Feed speed of the polishing sheet; 400 mm / min Rotation speed of the electrophotographic photoreceptor; 450 rpm Pressing of the electrophotographic photoreceptor into the backup roller; 3.5 mm Rotation direction of the polishing sheet and the electrophotographic photoreceptor; with Backup roller; outer diameter 100 mm, Asker C hardness 25 The polishing sheet A mounted on the polishing apparatus was produced by mixing the polishing abrasive grains used in GC3000 and GC2000 manufactured by Riken Korundum Co., Ltd. GC3000 (polishing sheet surface roughness Ra 0.83 μm) GC2000 (polishing sheet surface roughness Ra 1.45 μm) Polishing sheet A (polishing sheet surface roughness Ra 1.12 μm) The polishing time using the polishing sheet A was set to 20 seconds.

[0143] (Measurement of polishing depth L (μm)) For the electrophotographic photoreceptor after polishing, the maximum height Rmax was measured in accordance with JIS B 0601 1982 using a surface roughness measuring instrument SurfCodar SE3500 type manufactured by Kosaka Laboratory Ltd. The measurement conditions were set as follows. The 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 photoreceptor after surface polishing was 0.75 μm. Also, in Examples 1-2 to 1-25 described later, the polishing depth L of the electrophotographic photoreceptor subjected to surface processing was all 0.75 μm. (Measurement conditions) Detector: R2μm Stylus: Diamond needle of 0.7 mN Filter: 2CR Cutoff value: 0.08 mm Measurement length: 2.5 mm Feed speed: 0.1 mm

[0144] [[ID=4 three]] 〔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 the type and mass 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, respectively, in the formation of the protective layer.

[0145] [Table 3]

[0146] [Table 4]

[0147] <Evaluation of electrophotographic photoconductors> 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 mounted in a Canon ImagePRESS C910 copier and evaluated. For more details, the fabricated electrophotographic photoreceptor was mounted onto a magenta process cartridge, then placed in a magenta process cartridge station, and the evaluation was performed. The evaluation apparatus was set up in an environment with a temperature of 10°C and a relative humidity of 10%RH. The fabricated electrophotographic photoreceptor was mounted onto a magenta process cartridge, which was then placed in the magenta process cartridge station for evaluation.

[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 Canon ImagePRESS C910 copier (product name) (the charging method uses a DC voltage superimposed with an AC voltage applied to a roller-type contact charging element (charging roller), and the exposure method uses a laser image exposure method (wavelength 680 nm)) and evaluated. In detail, the evaluation apparatus was set up in an environment with a temperature of 10°C and a relative humidity of 10%RH. The fabricated electrophotographic photoreceptor was mounted on a magenta process cartridge, and then mounted on the magenta process cartridge station for evaluation. The charging conditions were adjusted so that the charging potential was -900V and the exposure potential was -400V, by adjusting the charging potential and the exposure amount of the exposure means.

[0150] The surface potential of the electrophotographic photoreceptor was measured by removing the developing cartridge from the evaluation apparatus described above and inserting a potential measuring device into its place. The potential measuring device consisted of a potential measuring probe (product name: model6000B-8, manufactured by Trek Japan Co., Ltd.) placed at the developing position of the developing cartridge. The position of the potential measuring probe relative to the electrophotographic photoreceptor was set to the center in the direction of the electrograph line of the electrophotographic photoreceptor, with a gap of 3 mm from the surface of the electrophotographic photoreceptor. Furthermore, the potential of the central part of the electrophotographic photoreceptor was measured using a surface potential meter (product name: model, manufactured by Trek Japan Co., Ltd.).

[0151] (Initial image evaluation) The image evaluation was carried out using the above evaluation device 1-1. Using A4-sized gloss paper, a solid white image was output, and the image defects due to dispersion defects included in the area corresponding to one circumference of the electrophotographic photoreceptor of the output image, that is, the number of black spots, were visually evaluated according to the following evaluation ranks. The area corresponding to one circumference of the electrophotographic photoreceptor is a rectangular area with a length of 297 mm, which is the long side length of A4 paper, and a width of 94.2 mm, which is the circumference of the electrophotographic photoreceptor. In the present invention, ranks A, B, C, and D are the levels at which the effects of the present invention are obtained, and among them, rank A is judged to be an excellent level. On the other hand, rank E is judged to be the level at which the effects of the present invention are not obtained. A: No black spots B: There are 1 or more and 3 or less black spots with a diameter less than 1.5 mm, and no black spots with a diameter of 1.5 mm or more C: There are 1 or more and 3 or less black spots with a diameter less than 1.5 mm, and 1 or more and 2 or less black spots with a diameter of 1.5 mm or more D: There are 4 or more and 5 or less black spots with a diameter less than 1.5 mm, and 2 or less black spots with a diameter of 1.5 mm or more E: There are 6 or more black spots with a diameter less than 1.5 mm, or 3 or more black spots with a diameter of 1.5 mm or more In this way, the evaluation results are shown in Table 5.

[0152] (Evaluation of ghost) Ghosting was evaluated by repeatedly outputting images using the evaluation device 1-1 described above, and then measuring the ghost potential using the evaluation device 1-2 described above. A cartridge equipped with an electrophotographic photoreceptor was attached to evaluation device 1-1, and 25,000 images of monochrome text images with a print density of 1% were repeatedly formed on A4 size plain paper. Next, the electrophotographic photoreceptor that had been used repeatedly was attached to the cartridge and attached to evaluation device 1-2. The ghost potential was measured by inputting a signal that outputs the image shown in Figure 5 into evaluation device 1-2. The image used for ghost evaluation is shown in Figure 5(a), in which a solid square image (black image) appears at the beginning of the image on a white background (white image), and then the 1-dot knight pattern image shown in Figure 5(b) is created. In evaluation device 1-2, the aforementioned potential measurement probe was fixed to the position of the solid square image (black image) in the signal that outputs the image shown in Figure 5. The applied bias was set so that the dark area potential of the unexposed part of the electrophotographic photoreceptor was -900V, and the exposure amount of the exposure means was adjusted so that the exposure potential was -400V. The signal that outputs the image shown in Figure 5 forms an electrostatic latent image on the surface of the photoreceptor corresponding to the image shown in Figure 5. In the electrostatic latent image corresponding to the image shown in Figure 5, the potential difference between the potential of the ghost image generation region in the knight pattern image formation region and the potential of the region other than the ghost image generation region in the knight pattern image formation region was defined as the ghost potential. Similarly, after repeating the image formation process 60,000 and 80,000 times, the ghost potential was evaluated. A lower ghost potential indicates better performance and demonstrates that the effects of the present invention have been achieved. The results of this evaluation are shown in Table 5.

[0153] [Table 5]

[0154] [Example 2-1] (Support 2) As the support (conductive support), a cylindrical aluminum cylinder (JIS-A3003, aluminum alloy, outer diameter 30 mm, length 357.5 mm, wall thickness 0.7 mm) was machined and used. Ultrasonic cleaning was performed in a cleaning solution containing detergent (product name: Chemicol CT, manufactured by Tokiwa Chemical Co., Ltd.) in pure water, followed by rinsing off the cleaning solution, and then further ultrasonic cleaning in pure water to degrease it, which was then used as support 2.

[0155] (Bottom layer 2) Zinc oxide particles (average particle size: 70 nm, specific surface area: 15 m²) 2 60 parts of ( / g) were mixed with 500 parts of tetrahydrofuran and stirred. 0.75 parts of a silane coupling agent (compound name: N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, trade name: KBM603, manufactured by Shin-Etsu Chemical Co., Ltd.) were added and the mixture was stirred for 2 hours. Subsequently, the tetrahydrofuran was removed by distillation under reduced pressure, and the mixture was heated and dried at 120°C for 3 hours to obtain surface-treated zinc oxide particles.

[0156] Next, 25 parts of butyral (product name: BM-1, manufactured by Sekisui Chemical Co., Ltd.) and 22.5 parts of blocked isocyanate (product name: Sumijool 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 using glass beads with a diameter of 1 mm in a sand mill. After dispersion treatment, 0.008 parts of dioctyltin dilaurate and 6.5 parts of silicone resin particles (Tospar 145, manufactured by GE Toshiba Silicone Co., Ltd.) were added and stirred to prepare a coating solution for the undercoat layer.

[0157] The obtained undercoating solution was applied to the support 2 by immersion to form a coating film, and the coating film was dried at 190°C for 24 minutes to form an undercoating 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° relative to CuKα characteristic X-rays, 10 parts of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Union Carbide Japan Co., Ltd.), and 300 parts of n-butyl alcohol were mixed and dispersed for 4 hours using a sand mill with glass beads with a diameter of 1 mm to prepare a coating solution for the charge generation layer. This charge generation layer coating solution was applied to the undercoat layer 2 by immersion, and the resulting coating film was dried at 150°C for 5 minutes to form a charge generation layer 2 with 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 roundness 0.85), 0.50 parts of the aforementioned graft copolymer 1, and 20 parts of tetrahydrofuran were stirred and mixed for 48 hours while maintaining a liquid temperature of 20°C to obtain preparation A.

[0160] Next, 45.0 parts of N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzicine, 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 were mixed and dissolved to obtain preparation B.

[0161] After adding preparation A to preparation B and stirring, the mixture was passed through a high-pressure disperser (product name: Microfluidizer M-110EH, manufactured by Microfluidics, Inc., USA) to obtain a dispersion. Subsequently, fluorine-modified silicone oil (product name: FL-100, manufactured by Shin-Etsu Silicone Co., Ltd.) was added to the dispersion to a concentration of 5 ppm, and the mixture was filtered using a polyflon filter (product name: PF-040, manufactured by Advantec Toyo Co., Ltd.) to prepare a coating solution for the charge transport layer.

[0162] This charge transport layer coating solution was applied to the charge generating layer 2 by immersion 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 with a thickness of 33 μm. In this way, an electrophotographic photoreceptor was fabricated.

[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 the type and mass 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, respectively, in the formation of the charge transport layer.

[0164] [Table 6]

[0165] [Table 7]

[0166] <Evaluation of electrophotographic photoconductors> The electrophotographic photoreceptors prepared 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] An electrophotographic photoconductor fabricated using electrophotographic photoconductors was installed in a Canon imageRUNNER ADVANCE DX C3835F (product name) copier and evaluated. In detail, the evaluation apparatus was set up in an environment with a temperature of 10°C and a relative humidity of 10%RH. The fabricated electrophotographic photoreceptor was mounted on a magenta process cartridge, and then mounted on the magenta process cartridge station for evaluation.

[0168] [Evaluation device 2-2] The electrophotographic photoreceptors prepared in Examples 2-1 to 2-40 and Comparative Examples 2-1 to 2-6 were evaluated by mounting them in a modified Canon imageRUNNER ADVANCE DX C3835F (product name) copier (the charging method uses a DC voltage applied to a roller-type contact charging element (charging roller), and the exposure method is a laser image exposure method (wavelength 780 nm)). Specifically, the evaluation apparatus was set up in an environment of 10°C and 10% RH relative humidity, and the electrophotographic photoreceptors prepared in the magenta process cartridges were mounted and then placed in the magenta process cartridge station for evaluation. The surface potential of the electrophotographic photoreceptor was measured by removing the developing cartridge from the evaluation apparatus described above and inserting a potential measuring device into it. The potential measuring device consisted of a potential measuring probe (product name: model6000B-8, manufactured by Trek Japan Co., Ltd.) placed at the developing position of the developing cartridge. The position of the potential measuring probe relative to the electrophotographic photoreceptor was set to the center in the direction of the electrograph line of the electrophotographic photoreceptor, with a gap of 3 mm from the surface of the electrophotographic photoreceptor. Furthermore, the potential of the central part of the electrophotographic photoreceptor was measured using a surface potential meter (product name: model344, manufactured by Trek Japan Co., Ltd.).

[0169] (Initial image evaluation) Image evaluation was performed using the evaluation apparatus 2-1 described above. Using A4 size gloss paper, an image with a completely solid white surface was output, and the number of image defects due to dispersion defects, i.e., black dots, contained within 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 area with a vertical dimension of 297 mm (the length of the long side of the A4 paper) and a horizontal dimension of 94.2 mm (the circumference of the electrophotographic photoreceptor). Furthermore, in this invention, ranks A, B, C, and D represent levels where the effects of the present invention are obtained, with rank A being judged to be an excellent level. On the other hand, rank E was judged to be a level where the effects of the present invention are not obtained. A: There are no black spots at all. B: There are 1 to 3 black spots less than 1.5 mm in diameter, and no black spots larger than 1.5 mm in diameter. C: One to three black dots less than 1.5 mm in diameter, AND one to two black dots 1.5 mm or larger in diameter. D: There are 4 to 5 black spots with a diameter of less than 1.5 mm, AND 2 or fewer black spots with a diameter of 1.5 mm or more. E: Six or more black spots less than 1.5 mm in diameter, or three or more black spots 1.5 mm or larger in diameter. The results of this evaluation are shown in Table 7.

[0170] (Ghost evaluation) The ghosting was evaluated by repeatedly outputting images using the evaluation device 2-1 described above, and then measuring the ghost potential using the evaluation device 2-2 described above. A cartridge equipped with an electrophotographic photoreceptor was attached to evaluation device 1-1, and 20,000 repeated image formations were performed on A4-sized plain paper using a single-color character image with a print density of 1%. Next, the electrophotographic photoreceptor that had been used repeatedly was attached to the cartridge and attached to evaluation device 1-2. The ghost potential was measured by inputting a signal that outputs the ghost evaluation image shown in Figure 5 into evaluation device 1-2. As shown in Figure 5(a), the ghost evaluation image is an image in which a solid square image (black image) appears at the beginning of the image on a white background (white image), and then the 1-dot knight pattern image shown in Figure 5(b) is created. In evaluation device 1-2, the aforementioned potential measurement probe was fixed to be positioned at the location of the solid square image (black image) in the signal that outputs the image shown in Figure 5. The applied bias was set so that the dark area potential of the unexposed part of the electrophotographic photoreceptor was -500V, and the laser light intensity was 0.30 μJ / cm². 2 The settings were configured as follows. The signal that outputs the image shown in Figure 5 forms an electrostatic latent image on the surface of the photoreceptor corresponding to the image shown in Figure 5. In the electrostatic latent image corresponding to the image shown in Figure 5, the potential difference between the potential of the ghost image generation region in the knight pattern image formation region and the potential of the region other than the ghost image generation region in the knight pattern image formation region was defined as the ghost potential. Similarly, after forming 40,000 and 55,000 images repeatedly, the ghost potential was evaluated. A lower ghost potential indicates better performance and that the effects of the present invention are achieved. The results of this evaluation are shown in Table 8.

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

[0172] 101 Base 102 Lower layer 103 Charge generation layer 104 Charge transport layer 105 Surface layer 2-1 Abrasive Sheet 2-2a Guide roller 2-2b Guide roller 2-2c Guide Roller 2-2d Guide Roller 2-3 Backup rollers 2-4 Object to be processed 2-5 Winding mechanism 2-6 Axis 1 Electrophotographic Photoreceptor 2. Charging means 3 Exposure light 4. Developing means 5. Transfer means 6 Transfer material 7. Pre-exposure light 8. Cleaning methods 9 Process Cartridges 10 Intermediate Transfer 11 Transfer paper 12 Paper feed path 13 Paper feed tray 14. Secondary transfer means 15 Fixing means 16 Paper output section 17 Process cartridge for yellow color 18 Process cartridges for magenta 19. Process cartridge for cyan color 20 Process cartridges for black color 41 White image 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, Contains 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 (2), and a compound represented by the following formula (3):

1. An electrophotographic photoreceptor comprising: 【Chemistry 1】 (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 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.) 【Chemistry 2】 (In formula (2), R ２１ represents a hydrogen atom or a methyl group, Y represents a divalent organic group; Z represents a polymer moiety. 【Chemistry 3】 (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 4】 (In formula (4), R ４１ represents an alkyl group having 1 to 4 carbon atoms.

2. The electrophotographic photoreceptor according to claim 1 , wherein the composition contains a compound represented by the following formula (5) as the compound represented by the formula (2): 【Chemistry 5】 (In 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 hydroxyl group, an ester bond (-COO-), an amide bond (-NHCO-), a urethane bond (-NHCOO-), or a divalent linking group derived by combining one or more selected from these groups and bonds with -O- or -S-, or a single bond, Z Ａ represents a structure represented by the following formula (2A), a cyano group, or a phenyl group, R ５１ , and R ５２ each independently represents a hydrogen atom or a methyl group, m is an integer between 25 and 150. 【Chemistry 6】 (In formula (2A), Z Ａ１ represents an alkyl group having 1 to 4 carbon atoms.

3. In the formula (5), -Y Ａ１ -Y Ｂ The structure represented 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 an unsubstituted alkylene group, Y Ａ２ represents a methylene group substituted with at least one atom selected from the group consisting of a hydroxy group and a halogen atom, Y Ａ３ represents an unsubstituted alkylene group, Y Ａ４ represents an ester bond, an amide bond, or a urethane bond, Y Ａ５ represents an unsubstituted alkylene group, Y Ａ６ represents an oxygen atom or a sulfur atom, b, c, d, e and f each independently represent 0 or 1. The electrophotographic photoreceptor according to claim 2 .

4. In the formula (1), n ​​Rf １ , and Rf ２ The electrophotographic photoreceptor according to any one of claims 1 to 3, wherein the total number of carbon atoms in the groups is 5 or more and 8 or less.

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

6. Rf in the formula (1) １ is a perfluoroalkylene group having 2 or 3 carbon atoms or a perfluoroalkylidene group having 2 or 3 carbon atoms, Rf ２ 6. The electrophotographic photoreceptor according to claim 1, wherein is a perfluoroalkyl group having 2 or 3 carbon atoms.

7. R in the formula (3) ３２ is a group represented by the formula (4), and R ４１ 7. The electrophotographic photoreceptor according to claim 1, wherein is a methyl group.

8. 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 (2), and the compound represented by formula (3) in the composition; The content of the compound represented by the formula (3) in the composition is 0.10 mol % or more and 1.0 mol % or less with respect to the content of the compound represented by the formula (1) in the composition. The electrophotographic photoreceptor according to any one of claims 1 to 7.

9. 9. The electrophotographic photoreceptor according to claim 8, 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.

10. The electrophotographic photoreceptor according to any one of claims 1 to 9, wherein 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).

11. The electrophotographic photoreceptor according to any one of claims 1 to 10, 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.

12. The electrophotographic photoreceptor according to any one of claims 1 to 11, wherein the weight average molecular weight of the polymer A is 16,000 or more and 100,000 or less.

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

14. the fluorine atom-containing resin particles are polytetrafluoroethylene resin particles, In a cross-sectional observation of the surface layer, the arithmetic average of the major axis of the 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. The electrophotographic photoreceptor according to any one of claims 1 to 13.

15. 15. A process cartridge which integrally supports the electrophotographic photosensitive member according to any one of claims 1 to 14 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.

16. 15. An electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1, a charging unit, an exposing unit, a developing unit, and a transferring unit.

17. A method for producing an electrophotographic photoreceptor having a surface layer, comprising the steps of: The manufacturing method comprises: 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 following formula (1), a compound represented by the following formula (2), and a compound represented by the following formula (3), A step of preparing a coating liquid for a surface layer comprising the steps of: forming a coating film of the coating liquid for the surface layer, and drying and / or curing the coating film to form the surface layer; having 2. A method for producing an electrophotographic photoreceptor comprising the steps of: 【Chemistry 7】 (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 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.) 【Chemistry 8】 (In formula (2), R ２１ represents a hydrogen atom or a methyl group, Y represents a divalent organic group; Z represents a polymer moiety. 【Chemistry 9】 (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 10】 (In formula (4), R ４１ represents an alkyl group having 1 to 4 carbon atoms.

Images