Electrophotographic apparatus
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- CANON KK
- Filing Date
- 2023-06-05
- Publication Date
- 2026-05-27
Smart Images
Figure 2024174667000001 
Figure 2024174667000002 
Figure 2024174667000003
Abstract
Description
[Technical field]
[0001] The present invention relates to an electrophotographic apparatus using an electrophotographic photoreceptor. [Background technology]
[0002] As an electrophotographic photoreceptor mounted in an electrophotographic device or a process cartridge, an organic electrophotographic photoreceptor (hereinafter, simply referred to as "electrophotographic photoreceptor" or "photoreceptor") containing an organic photoconductive material (charge generating material) is used. In recent years, there has been a demand for electrophotographic devices with a longer life, and therefore, there is a demand for an electrophotographic photoreceptor with improved image quality and wear resistance (mechanical durability). Furthermore, in recent electrophotographic devices, in addition to responding to the above-mentioned demand for longer life, there is also a demand for improving the efficiency of the transfer process to suppress toner scattering during transfer, thereby improving image quality and reducing waste toner.
[0003] Polycarbonate resin has been used as a binder resin for the charge transport layer of an electrophotographic photoreceptor. Strontium titanate has been used as an external additive for a toner for developing an electrostatic image for the purpose of controlling the chargeability of the toner. Patent Document 1 proposes an electrophotographic device using a polycarbonate resin as a binder resin for the charge transport layer of a photoreceptor and a toner using strontium titanate as an external additive.
[0004] Also, there has been a proposal to improve the durability of an electrophotographic photoreceptor by using a polyarylate resin, which has a higher mechanical strength than a polycarbonate resin, as a binder resin for a charge transport layer. Polyarylate resin is a type of aromatic dicarboxylic acid polyester resin. Patent Document 2 proposes a photoreceptor having improved durability and electrical properties by incorporating a polyarylate resin in a photosensitive layer. [Prior art documents] [Patent documents]
[0005] [Patent Document 1] Patent Publication No. 2021-131520 [Patent Document 2] JP 2011-227486 A Summary of the Invention [Problem to be solved by the invention]
[0006] According to the investigations of the present inventors, in an image forming apparatus in which the polycarbonate resin of the electrophotographic photoreceptor described in Patent Document 1 is replaced with the polyarylate resin described in Patent Document 2 for the purpose of improving the durability of the photoreceptor, there was room for improvement in transferability in a low-temperature, low-humidity environment after durability testing.
[0007] Therefore, an object of the present invention is to provide an electrophotographic device that has excellent transferability even under low temperature and low humidity conditions while maintaining the durability of an electrophotographic photosensitive member in an image forming apparatus that uses strontium titanate as an external additive for a toner. [Means for solving the problem]
[0008] The above object can be achieved by the present invention, which comprises: an electrophotographic photoreceptor having a surface layer containing resin X as a binder resin; a charging means for charging the surface of the electrophotographic photoreceptor; an exposure means for irradiating the charged surface of the electrophotographic photoreceptor with light to form an electrostatic latent image; a developing means for supplying toner to the electrostatic latent image to form a toner image; a transfer means for transferring the toner image onto a transfer medium, the toner contains strontium titanate as an external additive, The resin X is characterized in that it contains a structural unit represented by formula (1). [ka] Effect of the Invention
[0009] According to the present invention, it is possible to provide an electrophotographic apparatus that has excellent transferability even under low temperature and low humidity conditions while maintaining the durability of an electrophotographic photosensitive member in an image forming apparatus that uses strontium titanate as an external additive for a toner. [Brief description of the drawings]
[0010] [Figure 1] 1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having an electrophotographic photosensitive member according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0011] The present invention will be described in detail below with reference to preferred embodiments. In an image forming apparatus using an electrophotographic photoreceptor having a polycarbonate resin as described in Patent Document 1 and a toner to which strontium titanate is externally added, no deterioration in transferability occurs. However, in an image forming apparatus in which the polycarbonate resin is replaced with an electrophotographic photoreceptor containing a polyarylate resin for the purpose of improving durability, deterioration in transferability occurs under low temperature and low humidity conditions. From this, the present inventors speculate as follows about the reason why transferability deteriorates in an electrophotographic photoreceptor containing a polyarylate resin. When the surface of the photoconductor is charged, a discharge occurs from the charging member to the photoconductor. The discharge energy at this time causes discharge deterioration of the substance contained in the surface of the photoconductor, and specifically, the bond of the binder resin on the surface of the photoconductor may be broken. In polyarylate resin, the ester bond is broken by discharge, and COOH groups are easily generated. In particular, under low temperature and low humidity conditions, the discharge is unstable, so strong discharge may occur, and discharge deterioration is likely to occur. Therefore, a large number of COOH groups are likely to be generated on the surface of the photoconductor when it is used repeatedly for a long period of time. In addition, strontium titanate has a perovskite crystal structure, and titanium, which is a metal, and functional groups are likely to interact with each other. In particular, COOH shows a strong interaction by coordinating the orbit of titanium, which is a metal, with the unshared electron pair. For this reason, it is thought that the adhesion between the toner to which strontium titanate is added and the photoconductor containing polyarylate resin becomes strong during repeated use, causing deterioration in transferability. Polycarbonate is less likely to generate COOH groups, and has lower mechanical strength than polyarylate, so the COOH groups are easily removed by rubbing against the photoreceptor surface. Therefore, it is speculated that when strontium titanate was combined with conventional polycarbonate, there was no deterioration in transferability, but when combined with polyarylate, a deterioration in transferability occurred.
[0012] Based on the above speculation, the inventors have investigated various means for improving the durability of an electrophotographic photosensitive member without deteriorating the transferability by using strontium titanate as an external additive for a toner, and have arrived at the configuration of the present invention. Polyarylate resin has a structure in which a dicarboxylic acid-derived structure containing an aromatic ring and a diol (bisphenol) containing an aromatic ring are bonded. It was found that when the resin has an ether structure in the bond between the aromatic rings, it is resistant to discharge deterioration. Furthermore, when resin X, which simultaneously has an ether structure between the aromatic rings of the dicarboxylic acid-derived structure and the bisphenol-derived structure as shown in formula (1), is used, it is particularly resistant to discharge deterioration and is less likely to generate COOH groups. It is speculated that this prevents the adhesion with toner to which strontium titanate is externally added from becoming strong, improving transferability even in durability under low temperature and low humidity conditions.
[0013] [Electrophotographic photoreceptor] The electrophotographic photoreceptor of the present invention has at least a support and a photosensitive layer formed on the support. The method for producing the electrophotographic photoreceptor of the present invention includes a method of preparing the coating liquid for each layer described later, coating the layers in the desired order, and drying the liquid. In this case, the coating liquid can be applied by dip coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, ring coating, etc. Among these, dip coating is preferred from the viewpoint of efficiency and productivity. Each layer will be described below.
[0014] <Support> In the present invention, the electrophotographic photoreceptor has a support. In the present invention, the support is preferably a conductive support having electrical conductivity. The shape of the support may be a cylinder, a belt, a sheet, or the like. Among them, a cylindrical support is preferable. The surface of the support may be subjected to electrochemical treatment such as anodization, blasting, cutting, or the like. The support is preferably made of a metal, a resin, or a glass. Examples of the metal include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. Among them, an aluminum support using aluminum is preferable. Furthermore, the resin or glass may be made conductive by a process such as mixing with or coating with a conductive material.
[0015] <Conductive layer> In the present invention, a conductive layer may be provided on the support. By providing the conductive layer, it is possible to cover unevenness and defects of the support and prevent interference fringes. The average thickness of the conductive layer is preferably 5 μm or more and 40 μm or less. The conductive layer preferably contains conductive particles and a binder resin. Examples of the conductive particles include carbon black, metal particles, and metal oxide particles. Examples of the metal oxides include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, and bismuth oxide. Examples of the metals include aluminum, nickel, iron, nichrome, copper, zinc, and silver. Among these, it is preferable to use metal oxides as the conductive particles, and it is particularly preferable to use titanium oxide, tin oxide, or zinc oxide. When a metal oxide is used as the conductive particles, the surface of the metal oxide may be treated with a silane coupling agent or the like, or the metal oxide may be doped with an element such as phosphorus or aluminum or an oxide thereof. Examples of the doped element or oxide thereof include phosphorus, aluminum, niobium, and tantalum. The conductive particles may have a laminated structure having a core particle and a coating layer that covers the core particle. Examples of the core particle include titanium oxide, barium sulfate, zinc oxide, etc. Examples of the coating layer include metal oxides such as tin oxide and titanium oxide. When a metal oxide is used as the conductive particles, the volume average particle size thereof is preferably 1 nm or more and 500 nm or less.
[0016] Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, and alkyd resin. The conductive layer may further contain silicone oil, resin particles, a masking agent such as titanium oxide, and the like. The average thickness of the conductive layer is preferably 1 μm or more and 50 μm or less. The conductive layer can be formed by preparing a coating solution for the conductive layer containing the above-mentioned materials and solvent, forming a coating film of this, and drying it. Examples of the solvent used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Examples of the dispersion method for dispersing the conductive particles in the coating solution for the conductive layer include a method using a paint shaker, a sand mill, a ball mill, and a liquid collision type high-speed disperser.
[0017] <Undercoat layer> In the present invention, an undercoat layer may be provided on the support or the conductive layer. By providing an undercoat layer, the adhesion between layers can be improved and a charge injection blocking function can be imparted. The undercoat layer preferably contains a resin. Alternatively, the undercoat layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of the resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, acrylic resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinyl phenol resin, alkyd resin, polyvinyl alcohol resin, polyethylene oxide resin, polypropylene oxide resin, polyamide resin, polyamic acid resin, polyimide resin, polyamideimide resin, and cellulose resin. Examples of the polymerizable functional group contained in the monomer having a polymerizable functional group include an isocyanate group, a blocked isocyanate group, a methylol group, an alkylated methylol group, an epoxy group, a metal alkoxide group, a hydroxyl group, an amino group, a carboxy group, a thiol group, a carboxylic anhydride group, and a carbon-carbon double bond group.
[0018] For the purpose of improving electrical properties, the undercoat layer may further contain an electron transporting material, a metal oxide, a metal, a conductive polymer, etc. Among these, it is preferable to use an electron transporting material or a metal oxide. Examples of the electron transport substance include a quinone compound, an imide compound, a benzimidazole compound, a cyclopentadienylidene compound, a fluorenone compound, a xanthone compound, a benzophenone compound, a cyanovinyl compound, an aryl halide compound, a silole compound, a boron-containing compound, etc. An electron transport substance having a polymerizable functional group may be used as the electron transport substance, and the undercoat layer may be formed as a cured film by copolymerizing the electron transport substance with the monomer having the polymerizable functional group described above. Examples of metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, silicon dioxide, etc. Examples of metals include gold, silver, aluminum, etc. The undercoat layer may further contain an additive. The average thickness of the undercoat layer is preferably from 0.1 μm to 50 μm, more preferably from 0.2 μm to 40 μm, and particularly preferably from 0.3 μm to 30 μm. The undercoat layer can be formed by preparing a coating solution for the undercoat layer containing the above-mentioned materials and solvent, forming a coating film from the coating solution, and drying and / or curing the coating solution. Examples of the solvent used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.
[0019] <Photosensitive layer> The photosensitive layer of an electrophotographic photoreceptor is mainly classified into (1) a laminated type photosensitive layer and (2) a single-layer type photosensitive layer. (1) The laminated type photosensitive layer has a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. (2) The single-layer type photosensitive layer has a photosensitive layer containing both a charge generation material and a charge transport material. The electrophotographic photoreceptor according to the present invention preferably has a laminated type photosensitive layer.
[0020] (1) Laminated photosensitive layer The laminated photosensitive layer has a charge generating layer and a charge transport layer. In one embodiment of the present invention, the charge transport layer is the surface layer.
[0021] (1-1) Charge generation layer The charge generating layer preferably contains a charge generating material and a resin. The charge generating material used in the charge generating layer is preferably a phthalocyanine pigment, such as titanyl phthalocyanine, hydroxygallium phthalocyanine, or chlorogallium phthalocyanine, with titanyl phthalocyanine being more preferred. Examples of the binder resin used in the charge generating layer include resins (insulating resins) such as polyvinyl butyral resin, polyvinyl acetal resin, polyarylate resin, polycarbonate resin, polyester resin, polyvinyl acetate resin, polysulfone resin, polystyrene resin, phenoxy resin, acrylic resin, phenoxy resin, polyacrylamide resin, polyvinylpyridine resin, urethane resin, agarose resin, cellulose resin, casein resin, polyvinyl alcohol resin, polyvinylpyrrolidone resin, vinylidene chloride resin, acrylonitrile copolymer, and polyvinyl benzal resin. Organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinyl anthracene, and polyvinylpyrene can also be used. Only one type of binder resin may be used, or two or more types may be used in combination as a mixture or copolymer.
[0022] Examples of the solvent used in the charge generating layer coating liquid include toluene, xylene, tetralin, chlorobenzene, dichloromethane, chloroform, trichloroethylene, tetrachloroethylene, carbon tetrachloride, methyl acetate, ethyl acetate, propyl acetate, methyl formate, ethyl formate, acetone, methyl ethyl ketone, cyclohexanone, diethyl ether, dipropyl ether, propylene glycol monomethyl ether, dioxane, methylal, tetrahydrofuran, water, methanol, ethanol, n-propanol, isopropanol, butanol, methyl cellosolve, methoxypropanol, dimethylformamide, dimethylacetamide, dimethylsulfoxide, etc. The solvent may be used alone or in combination of one or more kinds. The charge generation layer can be obtained by dispersing a phthalocyanine pigment as a charge generation material and, if necessary, a binder resin in a solvent to prepare a coating liquid for the charge generation layer, forming a coating film of the coating liquid for the charge generation layer, and drying the coating film. The coating liquid for the charge generating layer may be prepared by adding only the charge generating material to a solvent and dispersing the material, and then adding the binder resin, or by adding the charge generating material and the binder resin together to a solvent and dispersing the material. In the above dispersion, a media type dispersing machine such as a sand mill or a ball mill, a liquid collision type dispersing machine, an ultrasonic dispersing machine or the like can be used.
[0023] (1-2) Charge transport layer When the surface layer of the present invention is a charge transport layer, the charge transport layer contains a binder resin and preferably contains a charge transport material.
[0024] [Binding resin] The binder resin used in the charge transport layer contains a resin X having a structural unit represented by formula (1). [ka]
[0025] Furthermore, it is preferable that the resin X further has a structural unit represented by formula (2). [ka] In formula (2), R 1 and R 2 represents a methyl group, and R 3 and R 4 are bonded together to represent a cycloalkylidene group having 5 or 6 carbon atoms, or R 1 and R 2 each independently represents a hydrogen atom or a methyl group; R 3 represents a methyl group, and R 4 represents a hydrogen atom or an alkyl group having 2 or 3 carbon atoms.
[0026] By including the structural units of formula (1) and formula (2), the wear resistance of the charge transport layer is improved and the suppression of discharge degradation is further improved. The reason for the improvement in wear resistance and the suppression of discharge degradation is presumed to be as follows. Formula (2) includes a dicarboxylic acid-derived structure and a bisphenol-derived structure. The dicarboxylic acid-derived structure includes an ether structure that is resistant to wear and discharge degradation, and the bisphenol-derived structure forms a bulky skeleton on one side.
[0027] R 1 and R 2 The presence of molecules having asymmetric positions and sizes with respect to the main chain, including the above, makes it easier to prevent uneven distribution of the binder resin and the charge transport material in the charge transport layer. This prevents uneven distribution of the binder resin and the charge transport material in the charge transport layer and makes them uniform, thereby allowing the structural units of formulas (1) and (2) in the charge transport layer to fully exhibit the effect of suppressing discharge degradation, thereby improving wear resistance and suppression of discharge degradation.
[0028] The ratio n2 / n1 of the number of structural units n1 represented by formula (1) contained in resin X to the number of structural units n2 represented by formula (2) contained in resin X of the charge transport layer is preferably 1.0 or more. If it is 10.0 or more, it is difficult to obtain the effects of wear resistance and suppression of discharge deterioration. More preferably, n2 / n1 is 1.0 or more and 3.0 or less.
[0029] Suitable examples of formula (2) include formula (2-1), formula (2-2), formula (2-3), formula (2-4) and formula (2-5). [ka] [ka] [ka] [ka] [ka] Furthermore, it is more preferable that the resin X contains the formula (2-5).
[0030] The viscosity average molecular weight of the resin X is preferably 10,000 or more, and more preferably 40,000 or more. When the viscosity average molecular weight of the resin X is 10,000 or more, the abrasion resistance of the photoreceptor is improved. On the other hand, the viscosity average molecular weight of the resin X is preferably 80,000 or less, and more preferably 70,000 or less. When the viscosity average molecular weight of the resin X is 80,000 or less, the resin X is easily dissolved in a solvent for forming the photosensitive layer.
[0031] The charge transport layer may further contain a resin other than the resin X containing a structural unit represented by formula (1) or formula (2) as a binder resin. Examples of the other resin include other polyarylate resins, polyester resins, polycarbonate resins, styrene resins, acrylic resins, etc. The polyarylate resin may be, for example, a random copolymer, an alternating copolymer, a periodic copolymer, or a block copolymer.
[0032] Other examples of the structural unit of the polyarylate resin include the following. [ka] [ka] [ka] [ka] [ka]
[0033] In addition, the resin X having a structural unit represented by formula (1) used in the binder resin of the surface layer of the electrophotographic photoreceptor of the present invention may have other structural units as long as it has a structural unit represented by formula (1), or may be a copolymer with a structural unit consisting of a group derived from another divalent carboxylic acid different from formula (1) and a divalent organic residue. The content of the resin X containing the structural units represented by formula (1) and formula (2) in the binder resin in the charge transport layer is preferably 50% by mass or more and 100% by mass or less.
[0034] It is preferable to further include a small amount of resin Y having the following structure as the binder resin in the charge transport layer, since this improves the transferability of the effects of the present invention. Resin Y contains at least one structural unit selected from the group consisting of formulas (PE1-1) and (PE1-2) as a structural unit derived from dicarboxylic acid, and at least one structural unit selected from the group consisting of (PE2-1) and (PE2-2) as a structural unit derived from diol. Preferably, resin Y is a resin represented by formula (PE-A). The content ratio of these resins Y in the charge transport layer is preferably 0.5% by mass or more and 6.0% by mass or less in terms of mass ratio. Note that the subscripts in the formula (for example, two 50.0 in formula PE-A) indicate the molar ratio (copolymerization ratio) of each unit. [ka] [ka] [ka] [ka] [ka]
[0035] The method for producing the resin X is not particularly limited. For example, a method of polycondensing bisphenol for forming a bisphenol-derived structure and dicarboxylic acid for forming a dicarboxylic acid-derived structure can be used. A known method can be used as the synthesis method for polycondensation. Bisphenol and dicarboxylic acid may be used as derivatives. As the derivative of bisphenol, aromatic diacetate may be used. Examples of the derivative of dicarboxylic acid include dicarboxylic acid dichloride, dicarboxylic acid dimethyl ester, dicarboxylic acid diethyl ester, and dicarboxylic acid anhydride. The ratio n1 / n2 can be adjusted by changing the types and amounts of bisphenol and dicarboxylic acid when producing resin X. The ratio n1 / n2 can be analyzed and calculated by nuclear magnetic resonance analysis or pyrolysis GC-MS analysis.
[0036] [Charge transport material] As the charge transport material, it is preferable to use compounds represented by the following formulas (20), (21), (22), (23), (24) and (25). [ka] [ka] [ka] [ka] [ka] [ka]
[0037] In formula (20), R 11 , R 12 , R 13 , and R 14each independently represents an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. 1 , a 2 , a 3 , and a 4 Each independently represents an integer of 0 to 5. 1 When represents an integer between 2 and 5, multiple R 11 may represent the same group or different groups. 2 When represents an integer between 2 and 5, multiple R 12 may represent the same group or different groups. 3 When represents an integer between 2 and 5, multiple R 13 may represent the same group or different groups. 4 When represents an integer between 2 and 5, multiple R 14 may represent the same group or different groups. 11 , R 12 , R 13 , and R 14 Each of the groups independently preferably represents an alkyl group having 1 to 3 carbon atoms, and more preferably represents a methyl group or an ethyl group. 1 , a 2 , a 3 , and a 4 preferably each independently represents an integer of 1 or more and 3 or less, and more preferably represents 1.
[0038] In formula (21), R 21 , R 22 , and R 23 R each independently represents an alkyl group having 1 to 6 carbon atoms. 24 , R 25 , and R 26 Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. 1 , b 2 , and b 3 Each independently represents 0 or 1. In formula (21), R 21 , R 22 , and R 23R preferably each independently represents an alkyl group having 1 to 3 carbon atoms, and more preferably represents a methyl group. 21 , R 22 , and R 23 is preferably bonded to the meta position of the phenyl group relative to the ethenyl group or the butadienyl group. 24 , R 25 , and 26 Each of b preferably represents a hydrogen atom. 1 , b 2 , and b 3 It is preferable that both of the symbols represent 0 or both of the symbols represent 1.
[0039] In formula (22), R 31 , R 32 , and R 33 R each independently represents an alkyl group having 1 to 6 carbon atoms. 34 represents an alkyl group having 1 to 6 carbon atoms or a hydrogen atom. 1 , d 2 , and d 3 Each independently represents an integer of 0 to 5. In formula (22), d 1 When represents an integer between 2 and 5, multiple R 31 may represent the same group or different groups. 2 When represents an integer between 2 and 5, multiple R 32 may represent the same group or different groups. 3 When represents an integer between 2 and 5, multiple R 33 may represent the same group or different groups. 34 preferably represents a hydrogen atom. 1 , d 2 , and d 3 Preferably, each represents 0.
[0040] In formula (23), R 41 , R 42 , R 43 , R 44 , R 45 , and R 46R each independently represents an alkyl group having 1 to 6 carbon atoms or a phenyl group. 47 and R 48 Each of e independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a phenyl group. 1 , e 2 , e 3 , and e 4 Each independently represents an integer of 0 to 5. 5 and e 6 Each independently represents an integer of 0 to 4. 7 and e 8 Each independently represents 0 or 1. In formula (23), e 1 When represents an integer between 2 and 5, multiple R 41 may represent the same group or different groups. 2 When represents an integer between 2 and 5, multiple R 42 may represent the same group or different groups. 3 When represents an integer between 2 and 5, multiple R 43 may represent the same group or different groups. 4 When represents an integer between 2 and 5, multiple R 44 may represent the same group or different groups. 5 When represents an integer between 2 and 4, multiple R 45 may represent the same group or different groups. 6 When represents an integer between 2 and 4, multiple R 46 may represent the same group or different groups. 41 ~R 46 R each independently preferably represents an alkyl group having 1 to 6 carbon atoms, more preferably represents an alkyl group having 1 to 3 carbon atoms, and further preferably represents a methyl group or an ethyl group. 47 and R 48 preferably represents a hydrogen atom. 1 , e 2 , e 3 , and e 4Each independently preferably represents an integer of 0 to 2, 1 and e 2 represents 0, e 3 and e 4 More preferably, e represents 2. 5 and e 6 Preferably, e represents 0. 7 and e 8 It is preferable that both of the symbols represent 0 or both of the symbols represent 1.
[0041] In formula (24), R 50 and R 51 R each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group. 52 , R 53 , R 54 , R 55 , R 56 , R 57 , and R 58 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms. 1 and f 2 Each independently represents an integer of 0 to 2. 3 and f 4 Each independently represents an integer of 0 to 5. In formula (24), f 3 When represents an integer between 2 and 5, multiple R 50 may represent the same group or different groups. 4 When represents an integer between 2 and 5, multiple R 51 may represent the same group or different groups. 50 and R 51 Each of R independently preferably represents an alkyl group having 1 to 6 carbon atoms. 52 and R 53 R preferably represents a hydrogen atom or a phenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms. 54 ~R 58Each of f independently preferably represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. 1 and f 2 It is preferable that all of f represent 0, all of f represent 1, or all of f represent 2. 3 and f4 each preferably independently represent 0 or 1. 50 and R 51 The alkyl group having 1 to 6 carbon atoms represented by R is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group. 52 and R 53 The phenyl group which may be substituted with an alkyl group having 1 to 6 carbon atoms, represented by the formula (I), is preferably a phenyl group or a phenyl group substituted at 1 to 5 positions with an alkyl group having 1 to 3 carbon atoms. The phenyl group substituted with an alkyl group having 1 to 3 carbon atoms is preferably a methylphenyl group, and more preferably a 4-methylphenyl group. 54 ~R 58 The alkyl group having 1 to 6 carbon atoms represented by R is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group, an ethyl group, or an n-butyl group. 54 ~R 58 The alkoxy group having 1 to 6 carbon atoms represented by the formula (I) is preferably an alkoxy group having 1 to 3 carbon atoms, and more preferably an ethoxy group.
[0042] In formula (25), R 61 , R 62 , R 63 , R 64 , R 65 , and R 66 each independently represents an alkyl group having 1 to 8 carbon atoms, a phenyl group, or an alkoxy group having 1 to 8 carbon atoms; h1, h2, h4, and h5 each independently represent an integer of 0 to 5; and h3 and h6 each independently represent an integer of 0 to 4.
[0043] A suitable example of the charge transport compound (20) is a compound represented by formula (H-11). A suitable example of the charge transport compound (21) is a compound represented by formula (H-7) and (H-8). A suitable example of the charge transport compound (22) is a compound represented by formula (H-6). A suitable example of the charge transport compound (23) is a compound represented by formula (H-9) and (H-10). A suitable example of the charge transport compound (24) is a compound represented by formula (H-1), (H-2), (H-3), and (H-5). A suitable example of the charge transport compound (25) is a compound represented by formula (H-4). Hereinafter, the compounds represented by formulas (H-1) to (H-11) may be referred to as charge transport compounds (H-1) to (H-11), respectively. [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka]
[0044] The content of the charge transport material is preferably 10 parts by weight or more and 200 parts by weight or less, more preferably 30 parts by weight or more and 120 parts by weight or less, and even more preferably 50 parts by weight or more and 100 parts by weight or less, relative to 100 parts by weight of the binder resin. The photosensitive layer may contain only one type of charge transport compound, or may contain two or more types of charge transport compounds. The photosensitive layer may further contain a charge transport compound other than the charge transport compounds (20), (21), (22), (23), (24), and (25) (hereinafter, sometimes referred to as other electron transport compounds or electron transport materials). Other examples of the charge transport compound include triphenylamine derivatives, diamine derivatives (e.g., N,N,N',N'-tetraphenylbenzidine derivatives, N,N,N',N'-tetraphenylphenylenediamine derivatives, N,N,N',N'-tetraphenylnaphthylenediamine derivatives, N,N,N',N'-tetraphenylphenanthrylenediamine derivatives, and di(aminophenylethenyl)benzene derivatives), oxadiazole-based compounds (e.g., 2,5-di(4-methylaminophenyl)-1,3,4-oxadiazole-based compounds, diazoles), styryl compounds (e.g., 9-(4-diethylaminostyryl)anthracene), carbazole compounds (e.g., polyvinylcarbazole), organic polysilane compounds, pyrazoline compounds (e.g., 1-phenyl-3-(p-dimethylaminophenyl)pyrazoline), hydrazone compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, and triazole compounds.
[0045] The charge transport layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slipping agents, and abrasion resistance improvers. Specific examples of such additives include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles. The average thickness of the charge transport layer is preferably from 5 μm to 50 μm, and more preferably from 8 μm to 40 μm. The charge transport layer can be formed by preparing a coating solution for the charge transport layer containing the above-mentioned materials and solvent, forming a coating film of this, and drying it. Examples of the solvent used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Among these solvents, ether-based solvents or aromatic hydrocarbon-based solvents are preferred.
[0046] (2) Single-layer photosensitive layer The single-layer type photosensitive layer can be formed by preparing a coating solution for the photosensitive layer containing a charge generating material, a charge transporting material, a resin and a solvent, forming a coating film of this, and drying it. The charge generating material, the charge transporting material and the resin are the same as the examples of materials in "(1) Multi-layer type photosensitive layer" above.
[0047] [toner] The toner according to the present invention has toner particles containing a binder resin and an external additive, and the external additive contains strontium titanate. Strontium titanate can adjust the chargeability and fluidity of the toner. The content of strontium titanate is 0.05 to 5.0 parts by mass relative to 100.0 parts by mass of the toner particles. It is preferably 0.1 to 1.0% by mass.
[0048] <Binding resin> The binder resin contained in the toner particles according to the present invention is not particularly limited and may be any known binder resin, but is preferably a vinyl resin, a polyester resin, etc. Examples of the vinyl resin, polyester resin, and other binder resins include the following resins or polymers. Homopolymers of styrene and its substituted derivatives such as polystyrene and polyvinyltoluene; styrene-based copolymers such as styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers, styrene-methyl acrylate copolymers, styrene-ethyl acrylate copolymers, styrene-butyl acrylate copolymers, styrene-octyl acrylate copolymers, styrene-dimethylaminoethyl acrylate copolymers, styrene-methyl methacrylate copolymers, styrene-ethyl methacrylate copolymers, styrene-butyl methacrylate copolymers, styrene-dimethylaminoethyl methacrylate copolymers, styrene-vinyl methyl ether copolymers, styrene-vinyl ethyl ether copolymers, styrene-vinyl methyl ketone copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-maleic acid copolymers, and styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resins, polyamide resins, epoxy resins, polyacrylic resins, rosin, modified rosin, terpene resins, phenolic resins, aliphatic or alicyclic hydrocarbon resins, and aromatic petroleum resins. These binder resins can be used alone or in combination, and styrene copolymers are preferred. The binder resin preferably contains a carboxy group, and is preferably a resin produced using a polymerizable monomer containing a carboxy group. Examples of the polymerizable monomer containing a carboxy group include acrylic acid, methacrylic acid; α-alkyl derivatives or β-alkyl derivatives of acrylic acid or methacrylic acid, such as α-ethylacrylic acid and crotonic acid; unsaturated dicarboxylic acids, such as fumaric acid, maleic acid, citraconic acid and itaconic acid; and unsaturated dicarboxylic acid monoester derivatives, such as succinic acid monoacryloyloxyethyl ester, succinic acid monoacryloyloxyethylene ester, phthalic acid monoacryloyloxyethyl ester, and phthalic acid monomethacryloyloxyethyl ester. As the polyester resin, a resin obtained by polycondensation of a carboxylic acid component and an alcohol component as shown below can be used. Examples of the carboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, fumaric acid, maleic acid, cyclohexanedicarboxylic acid, and trimellitic acid. Examples of the alcohol component include bisphenol A, hydrogenated bisphenol, an ethylene oxide adduct of bisphenol A, a propylene oxide adduct of bisphenol A, glycerin, trimethylolpropane, and pentaerythritol. The polyester resin may be a polyester resin containing a urea group. It is preferable that the carboxyl groups at the terminals of the polyester resin are not capped.
[0049] <Wax> The toner according to the present invention may contain a wax. The wax that is preferably used is as described above. The content of the wax is preferably 5.0 parts by mass or more and 20.0 parts by mass or less with respect to 100.0 parts by mass of the binder resin or the polymerizable monomer that produces the binder resin.
[0050] <Coloring agent> The colorant is not particularly limited, and any known colorant can be used. Examples of yellow pigments that can be used include condensed azo compounds such as yellow iron oxide, navel yellow, naphthol yellow S, Hansa yellow G, Hansa yellow 10G, benzidine yellow G, benzidine yellow GR, quinoline yellow lake, permanent yellow NCG, and tartrazine lake, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specific examples include the following. CI Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 155, 168, 180, 185, 193. Examples of red pigments include condensed azo compounds such as red iron oxide, permanent red 4R, lithol red, pyrazolone red, watching red calcium salt, lake red C, lake red D, brilliant carmine 6B, brilliant carmine 3B, eoxin lake, rhodamine lake B, and alizarin lake, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specific examples include the following. CI Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221, and 254. Examples of blue pigments include alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partial chloride, fast sky blue, copper phthalocyanine compounds such as indanthrene blue BG and their derivatives, anthraquinone compounds, basic dye lake compounds, etc. Specific examples include the following: CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, 66. Examples of black pigments include carbon black, aniline black, non-magnetic ferrite, magnetite, and pigments toned to black using the above-mentioned yellow, red and blue colorants. These colorants can be used alone or in combination, or in the form of a solid solution. If necessary, the colorant may be surface-treated with a substance that does not inhibit polymerization. The content of the colorant is preferably 3.0 parts by mass or more and 15.0 parts by mass or less with respect to 100.0 parts by mass of the binder resin or the polymerizable monomer that produces the binder resin.
[0051] <Charge control agent> The toner according to the present invention may contain a charge control agent. Any known charge control agent can be used. In particular, a charge control agent that has a high charging speed and can stably maintain a constant charge amount is preferred. Furthermore, when the toner particles are produced by a direct polymerization method, a charge control agent that has low polymerization inhibition properties and is substantially free of solubilized matter in an aqueous medium is preferred. As the charge control agent that controls the toner particles to have a negative charge, the following can be mentioned. Organometallic compounds and chelating compounds include monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, oxycarboxylic acids and dicarboxylic acid-based metal compounds. Other examples include aromatic oxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides or esters, and phenol derivatives such as bisphenol. Further examples include urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, and calixarenes. These charge control agents may be contained alone or in combination of two or more kinds. The amount of the charge control agent added is preferably 0.01 parts by mass or more and 10.0 parts by mass or less with respect to 100.0 parts by mass of the binder resin.
[0052] <Toner additives> The toner according to the present invention may contain, as an external additive, other external additives in addition to strontium titanate for the purpose of improving fluidity, chargeability, blocking properties, and the like. Examples of the external additive include inorganic fine particles such as silica fine particles, alumina fine particles, and titanium oxide fine particles. These may be used alone or in combination of two or more. These inorganic fine particles are preferably surface-treated with a silane coupling agent, a titanium coupling agent, a higher fatty acid, a silicone oil, or the like to improve heat-resistant storage stability and environmental stability. The total content of these various external additives is preferably 0.05 to 5.0 parts by mass relative to 100.0 parts by mass of toner particles. The content of strontium titanate is preferably 0.1 to 1.0 part by mass relative to 100.0 parts by mass of toner particles.
[0053] The toner particles can be produced by known means, and a kneading and grinding method or a wet production method can be used. From the viewpoint of uniformity of particle size and shape controllability, a wet production method is preferred. Examples of the wet production method include a suspension polymerization method, a dissolution suspension method, an emulsion polymerization aggregation method, and an emulsion aggregation method, and the emulsion aggregation method is more preferred. In other words, the toner particles are preferably emulsion aggregation toner particles. In the emulsion aggregation method, first, a dispersion of each material such as binder resin particles and colorant is prepared. The obtained dispersion of each material is dispersed and mixed by adding a dispersion stabilizer as necessary. Then, an aggregating agent is added to aggregate the particles to the desired toner particle size, and then or simultaneously with the aggregation, the resin particles are fused together. If necessary, the shape is controlled by heat to form toner particles.
[0054] The following can be used as the dispersion stabilizer. As the surfactant, a known cationic surfactant, anionic surfactant, or nonionic surfactant can be used. Examples of inorganic dispersion stabilizers include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, and alumina. Examples of the organic dispersion stabilizer include polyvinyl alcohol, gelatin, methyl cellulose, methylhydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, and starch. As the flocculant, in addition to surfactants having the opposite polarity to the surfactants used in the dispersion stabilizer, inorganic salts and inorganic metal salts having a valence of 2 or more can be suitably used. In particular, inorganic metal salts are preferred because they facilitate the control of the flocculation property and the charge property of the toner by ionizing the polyvalent metal element in an aqueous medium. Specific examples of preferred inorganic metal salts include metal salts of calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, iron chloride, aluminum chloride, and aluminum sulfate, as well as inorganic metal salt polymers of polyiron chloride, polysilica iron, polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Among these, aluminum salts and their polymers, and polysilica iron are particularly suitable. In general, in order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is preferably 2-valent rather than 1-valent, and 3-valent or more rather than 2-valent, and even if the valence is the same, inorganic metal salt polymers are more suitable. Examples of the external addition device that can be used include a double cone mixer, a V-type mixer, a drum type mixer, a super mixer, an FM mixer (manufactured by Nippon Coke & Engineering Co., Ltd.), a Nauta mixer, a Mechano Hybrid, etc. To control the coating state of the external additive, the toner can be prepared by adjusting the rotation speed, processing time, and water temperature and amount of water in the jacket of the external addition device. From the viewpoint of high definition and high resolution of an image, it is preferable that the weight average particle size of the toner particles is 3.0 μm or more and 10.0 μm or less.
[0055] <Process cartridge and electrophotographic apparatus> An example of the schematic configuration of an electrophotographic apparatus having a process cartridge equipped with an electrophotographic photosensitive member is shown in Figure 1. In Figure 1, reference numeral 1 denotes a cylindrical (drum-shaped) electrophotographic photosensitive member, which is driven to rotate around an axis 2 in the direction of the arrow at a predetermined peripheral speed (process speed). During the rotation process, the surface of the electrophotographic photoreceptor 1 is charged to a predetermined positive or negative potential by a charging means 3. Next, the charged surface of the electrophotographic photoreceptor 1 is irradiated with exposure light 4 from an exposure means (not shown), and an electrostatic latent image corresponding to the target image information is formed. The image exposure light 4 is light that is intensity-modulated in response to a time-series electric digital image signal of the target image information, which is output from an exposure means such as a slit exposure or laser beam scanning exposure. The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed (normal development or reversal development) by supplying toner contained in the developing means 5, and a toner image is formed on the surface of the electrophotographic photoreceptor 1. The toner image formed on the surface of the electrophotographic photoreceptor 1 is transferred to the transfer medium 7 by the transfer means 6. At this time, a bias voltage of a polarity opposite to that of the charge held by the toner is applied to the transfer means 6 from a bias power source (not shown). Furthermore, when the transfer medium 7 is paper, the transfer medium 7 is taken out from a paper feed section (not shown) and fed between the electrophotographic photoreceptor 1 and the transfer means 6 in synchronization with the rotation of the electrophotographic photoreceptor 1. The transfer medium 7 onto which the toner image has been transferred from the electrophotographic photoreceptor 1 is separated from the surface of the electrophotographic photoreceptor 1, and then conveyed to a fixing means 8, where the toner image is fixed, and the image is printed out as an image formed product (print, copy) outside the electrophotographic device. The surface of the electrophotographic photoreceptor 1 after the toner image has been transferred to the transfer medium 7 is cleaned by removing adhesions such as toner (transfer residual toner) by a cleaning means 9. The transfer residual toner can also be directly removed by a developing device or the like by a cleanerless system that has been developed in recent years. Furthermore, the surface of the electrophotographic photoreceptor 1 is repeatedly used for image formation after being subjected to a charge removal process by pre-exposure light 10 from a pre-exposure means (not shown). Note that when the charging means 3 is a contact charging means using a charging roller or the like, the pre-exposure means is not necessarily required. In the present invention, a plurality of components among the components such as the electrophotographic photoreceptor 1, the charging means 3, the developing means 5, and the cleaning means 9 described above are housed in a container and supported as a unit to form a process cartridge. This process cartridge can be configured to be freely attached to and detached from the main body of the electrophotographic device. For example, at least one selected from the charging means 3, the developing means 5, and the cleaning means 9 is integrally supported together with the electrophotographic photosensitive member 1 to form a cartridge. A process cartridge 11 can be formed that is detachably attached to the main body of the electrophotographic apparatus using a guide means 12 such as a rail of the main body of the electrophotographic apparatus. When the electrophotographic apparatus is a copying machine or a printer, the exposure light 4 may be reflected light or transmitted light from an original. Alternatively, the exposure light 4 may be light emitted by scanning a laser beam, driving an LED array, or driving a liquid crystal shutter array in accordance with a signal obtained by reading an original with a sensor and converting it into a signal. The electrophotographic photoreceptor 1 can be widely used in electrophotographic application fields such as laser beam printers, CRT printers, LED printers, FAX machines, liquid crystal printers, and laser plate making. EXAMPLES
[0056] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited to the following examples without departing from the gist of the present invention. In the following examples, "parts" are based on mass unless otherwise specified.
[0057] [Resin X] (Resin X(P1)) As a synthesis example, a method for synthesizing a resin X represented by the following (P1) will be shown below. A dicarboxylic acid chloride having a structure represented by the following formula (DC-1) was dissolved in dichloromethane to prepare an acid chloride solution. In addition to this acid chloride solution, bisphenols having structures represented by the following formulas (BP-1) and (BP-2) were mixed in a molar ratio of 27:23 and dissolved in a 10% aqueous sodium hydroxide solution. To this was added tributylbenzylammonium chloride as a polymerization catalyst and the mixture was stirred to prepare a bisphenol solution. Next, the acid chloride solution was added to the bisphenol solution with stirring to initiate polymerization. The polymerization was carried out for 3 hours with stirring while maintaining the reaction temperature at 25°C or less. Thereafter, acetic acid was added to terminate the polymerization reaction, and washing with water was repeated until the aqueous layer became neutral. After washing, the polymer was dropped into stirred methanol to precipitate the polymer, and the polymer was dried in a vacuum to obtain resin X represented by (P1). The viscosity average molecular weight of the obtained (P1) was 46,000. Note that the subscripts in the formula (for example, the two 54.0 and 46.0 in formula P1) indicate the molar ratio (copolymerization ratio) of each unit. [ka] [ka] [ka] [ka]
[0058] (Resin X(P2)~(P15)) Resins X (P2) to (P15) were produced in the same manner as Resin X (P1), except that the bisphenol used in the production of Resin X (P1) was changed and adjusted to the ratio shown in Table 1. Table 1 also shows the viscosity average molecular weight of Resin X.
[0059] [Table 1]
[0060] The structures of Resin X (P2) to (P15) are shown below. [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka]
[0061] [Resin Y] PE-A was prepared as resin Y. The viscosity average molecular weight was 23,000.
[0062] <Manufacture of electrophotographic photoreceptor> The thickness of each layer of the electrophotographic photoreceptor, except for the charge generation layer, was measured by a method using an eddy current film thickness meter (Fischerscope, manufactured by Fisher Instruments) or a method of converting the specific gravity from the mass per unit area. The film thickness of the charge generation layer was measured by converting the Macbeth density value of the photoreceptor using a calibration curve previously obtained from the Macbeth density value measured by pressing a spectrodensitometer (product name: X-Rite504 / 508, manufactured by X-Rite) against the surface of the photoreceptor and the film thickness measurement value by observing a cross-sectional SEM image.
[0063] [Photoreceptor 1] <Conductive layer> An aluminum cylinder (JIS-A3003, aluminum alloy) having a diameter of 24 mm and a length of 257.5 mm was used as a support (conductive support). Next, the following materials were prepared: Metal oxide particles such as oxygen-deficient tin oxide (SnO 2 ) coated with titanium dioxide (TiO 2 ) particles (average primary particle diameter 230 nm) 214 parts Phenolic resin as a binding material (phenolic resin monomer / oligomer) (product name: Plyofen J-325, manufactured by DIC Corporation, resin solid content: 60% by mass) 132 parts 98 parts of 1-methoxy-2-propanol as solvent These were placed in a sand mill using 450 parts of glass beads with a diameter of 0.8 mm, and dispersion treatment was performed under the conditions of rotation speed: 2000 rpm, dispersion treatment time: 4.5 hours, and cooling water temperature setting: 18 ° C. to obtain a dispersion liquid. The glass beads were removed from this dispersion liquid using a mesh (opening: 150 μm). Silicone resin particles (trade name: Tospearl 120, manufactured by Momentive Performance Materials Co., Ltd., average particle size 2 μm) were added to the obtained dispersion liquid as a surface roughening agent. The amount of silicone resin particles added was 10 mass % of the total mass of the metal oxide particles and binding material in the dispersion liquid after removing the glass beads. In addition, silicone oil (trade name: SH28PA, manufactured by Toray Dow Corning Co., Ltd.) was added to the dispersion liquid as a leveling agent so that the amount was 0.01 mass % of the total mass of the metal oxide particles and binding material in the dispersion liquid. Next, a mixed solvent of methanol and 1-methoxy-2-propanol (mass ratio 1:1) was added to the dispersion so that the total mass of the metal oxide particles, the binder material, and the surface roughening agent in the dispersion (i.e., the mass of the solid content) was 67 mass% relative to the mass of the dispersion. Then, the mixture was stirred to prepare a coating liquid for a conductive layer. The coating liquid for a conductive layer was dip-coated on a support and heated at 140°C for 1 hour to form a conductive layer with a thickness of 30 μm.
[0064] <Undercoat layer> Surface-treated titanium oxide (number average primary particle diameter 10 nm) was prepared. Titanium oxide was surface-treated using alumina and silica, and the surface-treated titanium oxide was further surface-treated using methylhydrogenpolysiloxane while wet-dispersing. Next, 2 parts by mass of the surface-treated titanium oxide, 1 part by mass of polyamide resin ("Amilan CM8000" manufactured by Toray Industries, Inc., a tetrapolymer polyamide resin of polyamide 6, polyamide 12, polyamide 66 and polyamide 610), 10 parts by mass of methanol, 1 part by mass of butanol and 1 part by mass of toluene were mixed for 5 hours using a bead mill to obtain a coating liquid for an undercoat layer. Thereafter, the obtained coating liquid for an undercoat layer was dip-coated on the conductive substrate prepared as above to form a coating film, and the coating film was thermally dried at 130°C for 30 minutes to form an undercoat layer having a film thickness of 1.5 μm. An aluminum drum-shaped support was used as the conductive substrate.
[0065] <Charge generation layer> A Y-type titanyl phthalocyanine (1.5 parts by mass) as a charge generating material and a polyvinyl acetal resin ("S-LEC BX-5" manufactured by Sekisui Chemical Co., Ltd.) (1 part by mass) were added to a solvent containing propylene glycol monomethyl ether (40 parts by mass) and tetrahydrofuran (40 parts by mass). These materials and the solvent were mixed for 12 hours using a bead mill to disperse the materials in the solvent, thereby preparing a coating liquid for a charge generating layer. The obtained coating liquid for a charge generating layer was dip-coated on the undercoat layer to form a coating film, and the coating film was heated and dried at a temperature of 100°C for 10 minutes to form a charge generating layer having a thickness of 0.25 μm.
[0066] <Charge transport layer> A coating liquid for a charge transport layer was prepared by mixing 6 parts by mass of (HTM-1) as a charge transport material, 4.5 parts by mass of resin X (P1) as a binder resin, 5.5 parts by mass of a polyarylate resin (P16) containing a structural unit represented by the following formula, 67.5 parts by mass of tetrahydrofuran, and 22.5 parts by mass of toluene. The obtained coating liquid for a charge transport layer was dip-coated on the charge generating layer to form a coating film, and the coating film was dried by heating at a temperature of 120° C. for 30 minutes to form a charge transport layer having a thickness of 18 μm. [ka] (Viscosity average molecular weight 40000)
[0067] [Photoconductor 2~34, Photoconductor A~N] Electrophotographic photoreceptors were prepared by modifying the above <Photoreceptor 1> so that the charge transport material, binder resin, and content of the charge transport material relative to the content of the binder resin in the charge transport layer, i.e., in the surface layer, were as shown in Table 2.
[0068] [Table 2]
[0069] The polyarylate resins (P17) to (P25) each contain a structural unit represented by the following formula: [ka] (Viscosity average molecular weight 42000) [ka] (Viscosity average molecular weight 42500) [ka] (Viscosity average molecular weight 42300) [ka] (Viscosity average molecular weight 43300) [ka] (Viscosity average molecular weight 41600) [ka] (Viscosity average molecular weight 42900) [ka] (Viscosity average molecular weight 44000) [ka] (Viscosity average molecular weight 45000) [ka] (Viscosity average molecular weight 46200)
[0070] (Polycarbonate resin) The following polycarbonate resins were prepared: Mitsubishi Gas Chemical Co., Ltd. "Iupilon Z400" (viscosity average molecular weight 40,000) An example of toner production will now be described.
[0071] <Preparation example of binder resin particle dispersion> 78.0 parts of styrene, 20.7 parts of butyl acrylate, 1.3 parts of acrylic acid as a carboxyl group-imparting monomer, and 3.2 parts of n-lauryl mercaptan were mixed and dissolved. An aqueous solution of 1.5 parts of NEOGEN RK (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) in 150 parts of ion-exchanged water was added to this solution and dispersed. An aqueous solution of 0.3 parts of potassium persulfate and 10 parts of ion-exchanged water was added while slowly stirring for another 10 minutes. After nitrogen replacement, emulsion polymerization was carried out at 70°C for 6 hours. After polymerization was completed, the reaction solution was cooled to room temperature, and ion-exchanged water was added to obtain resin particle dispersion 1 with a solid content of 12.5% by mass and a volume-based median diameter of 0.2 μm. A part of the obtained resin particles was washed with pure water to remove the surfactant and dried under reduced pressure in order to measure the acid value of the resin. The acid value of the resin was measured and confirmed to be 9.5 mgKOH / g.
[0072] <Preparation example of release agent dispersion> 100 parts of behenyl behenate (melting point: 72.1°C) and 15 parts of NEOGEN RK were mixed with 385 parts of ion-exchanged water, and dispersed for about 1 hour using a wet jet mill JN100 (manufactured by Jokou Co., Ltd.) to obtain a release agent dispersion. The concentration of the release agent dispersion was 20% by mass.
[0073] <Preparation example of colorant dispersion> As a colorant, 100 parts of carbon black "Nipex35 (manufactured by Orion Engineered Carbons)" and 15 parts of Neogen RK were mixed with 885 parts of ion-exchanged water, and dispersed for about 1 hour using a wet jet mill JN100 to obtain a colorant dispersion.
[0074] <Toner manufacturing example> 265 parts of resin particle dispersion, 1:10 parts of wax dispersion, and 10 parts of colorant dispersion were dispersed using a homogenizer (IKA Ultra Turrax T50) while stirring. The temperature inside the vessel was adjusted to 30° C., and a 1 mol / L aqueous solution of sodium hydroxide was added to adjust the pH to 8.0. As a flocculant, an aqueous solution of 0.25 parts of aluminum chloride dissolved in 10 parts of ion-exchanged water was added over 10 minutes at 30°C while stirring. After leaving it for 3 minutes, the temperature was raised to 50°C to generate associated particles. In this state, the particle size of the associated particles was measured using a Coulter Counter Multisizer 3 (registered trademark, manufactured by Beckman Coulter, Inc.). When the weight average particle size reached 6.0 μm, 0.9 parts of sodium chloride and 5.0 parts of Neogen RK were added to stop particle growth. After adjusting the pH to 9.0 by adding 1 mol / L aqueous sodium hydroxide solution, the temperature was raised to 95° C. to spheroidize the aggregated particles. When the average circularity reached 0.980, the temperature was lowered and the mixture was cooled to room temperature to obtain a toner particle dispersion. Hydrochloric acid was added to the obtained toner particle dispersion to adjust the pH to 1.5 or less, and the mixture was left to stir for 1 hour, and then the mixture was subjected to solid-liquid separation using a pressure filter to obtain a toner cake. This was reslurried with ion-exchanged water to make a dispersion again, and then the mixture was subjected to solid-liquid separation using the above-mentioned filter. The reslurry and solid-liquid separation were repeated until the electrical conductivity of the filtrate was 5.0 μS / cm or less, and finally the mixture was subjected to solid-liquid separation to obtain a toner cake. The obtained toner cake was dried and further classified using a classifier so that the weight average particle size (D4) was 6.0 μm, and toner particles were obtained. Strontium titanate particles (0.7 parts) (number average primary particle diameter 70 nm) and silica particles (2.5 parts) (number average primary particle diameter 12 nm) surface-treated with dimethyl silicone oil were externally mixed with the toner particles (100 parts) obtained above using an FM10C (manufactured by Nippon Coke & Engineering Co., Ltd.). The external addition conditions were as follows: the lower blade was set to A0 blade, the gap between the blade and the wall of the deflector was set to 20 mm, the amount of toner particles charged was 2.0 kg, the rotation speed was 66.6 s-1, the external addition time was 10 minutes, and the cooling water temperature was set to 20°C and the flow rate was 10 L / min. Thereafter, the mixture was sieved through a mesh having an opening of 200 μm to obtain a toner.
[0075] <Example 1> <Evaluation> The electrophotographic photoreceptor and toner prepared above were used to carry out the following evaluations. The evaluation results are shown in Table 3. The electrophotographic device used was a modified version of a laser beam printer manufactured by Hewlett-Packard Co., Ltd., product name HP LaserJet Enterprise Color M553dn, which was modified to allow adjustment and measurement of the voltage applied to the charging roller, adjustment and measurement of the amount of image exposure light, and adjustment and measurement of the voltage applied in the transfer process. The toner was removed from the black toner cartridge and replaced with the prepared toner. Also, the photoconductor 1 was attached to the black toner cartridge. Next, in a low-temperature, low-humidity environment of 15°C and 10% RH, 10,000 images were printed on A4-sized plain paper using a test chart with a print ratio of 1%. The charging conditions were a dark potential of -500V, and the exposure conditions were an image exposure light amount of 0.25 μJ / cm 2 The paper used was plain paper CS-680 (68 g / m 2 ) (Canon Marketing Japan Inc.) was used.
[0076] [Evaluation of wear resistance] The amount of wear of the charge transport layer was determined from the difference in the photoreceptor film thickness before and after repeated image output of 10,000 sheets.
[0077] [Evaluation of transferability] After repeatedly outputting 10,000 images, a 30 mm wide solid image was output vertically on plain paper CS-680, and the output during solid image formation was stopped and the residual toner on the electrophotographic photoreceptor was collected using a transparent polyester tape (polyester tape 5511, Nichiban). The density of the residual toner was measured by the following method. The transparent tape on which the residual toner was collected after peeling from the surface of the electrophotographic photoreceptor and a new transparent tape were each attached to a high whiteness paper (GFC081 Canon). Then, the density D1 of the transparent tape on the residual toner collecting portion and the density D0 of the new transparent tape portion were each measured with an X-Rite color reflection densitometer (X-rite 500 Series, manufactured by X-rite Corporation). The difference obtained by the measurement, "D1-D0", was taken as the density of the residual toner. The smaller the value of the residual toner density, the less the amount of the residual toner.
[0078] (Evaluation Criteria) A: Transfer residual density is less than 0.02 B: Transfer residual density is 0.02 or more and less than 0.06 C: Transfer residual density is 0.06 or more and less than 0.10 D: Transfer residual density is 0.10 or more
[0079] The results are shown in Table 3. [Table 3]
[0080] <Examples 2 to 34> In Examples 2 to 34, process cartridges were produced using photoreceptors 2 to 34 and toners, respectively, as shown in Table 3, and an image output test was carried out in the same manner as in Example 1. The evaluation results for each are shown in Table 3.
[0081] <Comparative Examples 1 to 14> In Comparative Examples 1 to 14, process cartridges were produced using the photoreceptors A to N and toners shown in Table 3, respectively, and an image output test was carried out in the same manner as in Example 1. The evaluation results for each are shown in Table 3.
[0082] The embodiments of the present invention include the following configurations. [Configuration 1] an electrophotographic photoreceptor having a surface layer containing resin X as a binder resin; a charging means for charging the surface of the electrophotographic photoreceptor; an exposure means for irradiating the charged surface of the electrophotographic photoreceptor with light to form an electrostatic latent image; a developing means for supplying toner to the electrostatic latent image to form a toner image; a transfer means for transferring the toner image onto a transfer medium, the toner contains strontium titanate as an external additive, The electrophotographic device, wherein the resin X contains a structural unit represented by formula (1). [ka] [Configuration 2] The electrophotographic apparatus according to Configuration 1, wherein the resin X further contains a structural unit represented by formula (2). [ka] (In formula (2), R 1 and R 2 represents a methyl group, and R 3 and R 4 are bonded together to represent a cycloalkylidene group having 5 or 6 carbon atoms, or R 1 and R 2 each independently represents a hydrogen atom or a methyl group; R 3 represents a methyl group, and R 4 represents a hydrogen atom or an alkyl group having 2 or 3 carbon atoms. [Configuration 3] With respect to the number n2 of structural units represented by formula (2) contained in the resin X, 3. The electrophotographic apparatus according to claim 2, wherein the ratio n2 / n1 of the number n1 of the structural units represented by formula (1) contained in the resin X is 1.0 or more. [Configuration 4] The electrophotographic apparatus according to configuration 2 or 3, wherein the content of resin X containing the structural units represented by formula (1) and formula (2) in the binder resin in the surface layer is 50% by mass or more and 100% by mass or less. [Configuration 5] 5. The electrophotographic apparatus according to any one of configurations 2 to 4, wherein the structural unit represented by formula (2) is a structural unit represented by formula (2-1), (2-2), (2-3), (2-4), or (2-5). [ka] [ka] [ka] [ka] [ka] [Configuration 6] 6. The electrophotographic apparatus according to any one of configurations 2 to 5, wherein the structural unit represented by formula (2) is a structural unit represented by formula (2-5). [ka] [Configuration 7] The electrophotographic device according to any one of Structures 1 to 6, wherein the surface layer further contains a resin Y having at least one structural unit selected from the group consisting of formulas (PE1-1) and (PE1-2), and at least one structural unit selected from the group consisting of formulas (PE2-1) and (PE2-2). [ka] [ka] [ka] [ka] [Configuration 8] 8. The electrophotographic apparatus according to claim 1, wherein the mass of the strontium titanate relative to the mass of the toner particles in the toner is 0.1 to 1.0% by mass. [Explanation of symbols]
[0083] 1: Electrophotographic photoreceptor 2: Axis 3: Charging means 4: Image exposure light 5: Developing method 6: Transfer method 7: Transfer medium 8: Image fixing means 9: Cleaning means 10: Pre-exposure light 11: Process cartridge 12: Guidance means
Claims
1. An electrophotographic photoreceptor having a surface layer containing a binder resin, A charging means for charging the surface of the electrophotographic photoreceptor, An exposure means for irradiating light onto the surface of the charged electrophotographic photoreceptor to form an electrostatic latent image, A developing means that supplies toner to the electrostatic latent image to form a toner image, A transfer means for transferring the toner image onto a transfer medium, An electrophotographic apparatus having, The developing means includes the toner, The toner comprises toner particles and an external additive. The external additive contains strontium titanate, The aforementioned binding resin includes resin X, The resin X includes a structural unit represented by the following formula (1): An electrophotographic apparatus characterized by the following features. 【Chemistry 1】
2. The electrophotographic apparatus according to claim 1, wherein the resin X further includes a structural unit represented by the following formula (2). 【Chemistry 2】 (In formula (2), R １ and R ２ represents a methyl group, R ３ and R ４ These are bonded together to represent a cycloalkylidene group with 5 or 6 carbon atoms, or R １ and R ２ Each of these independently represents either a hydrogen atom or a methyl group, R ３ represents a methyl group, R ４ (This represents a hydrogen atom, or an alkyl group having 2 or 3 carbon atoms.)
3. The electrophotographic apparatus according to claim 2, wherein when the number of structural units represented by formula (2) contained in the resin X is n2, and the number of structural units represented by formula (1) contained in the resin X is n1, n2 / n1 is 1.0 or more.
4. The electrophotographic apparatus according to claim 2, wherein the content of the resin X in the binder resin in the surface layer is 50% by mass or more and 100% by mass or less.
5. The electrophotographic apparatus according to claim 2, wherein the resin X includes structural units represented by the following formulas (2-1), (2-2), (2-3), (2-4), or (2-5) as structural units represented by formula (2). 【Transformation 3】 【Chemistry 4】 【Transformation 5】 【Transformation 6】 【Transformation 7】
6. The electrophotographic apparatus according to claim 2, wherein the resin X includes structural units represented by the following formula (2-5) as structural units represented by formula (2). 【Transformation 8】
7. The surface layer further comprises resin Y, The aforementioned resin Y A structural unit selected from the group consisting of structural units represented by the following formula (PE1-1) and structural units represented by the following formula (PE1-2), A structural unit selected from the group consisting of structural units represented by the following formula (PE2-1) and structural units represented by the following formula (PE2-2), Having, The electrophotographic apparatus according to claim 1 or 2. 【Chemistry 9】 【Chemistry 10】 【Chemistry 11】 【Chemistry 12】
8. The electrophotographic apparatus according to claim 1 or 2, wherein the mass of strontium titanate relative to the toner particles in the toner is 0.1 to 1.0% by mass.