Electro-photographic photoreceptor, process cartridge and electro-photographic device, and method for producing hydroxy phthalocyanine crystal

Abstract

To provide an electro-photographic photoreceptor having a low absolute value of a potential in an exposed part even in an electro-photographic device in a high speed printing process, as well as a highly stable potential in the exposed part without being affected by fluctuations in the humidity of an environment in which the electro-photographic device is used.SOLUTION: Provided is an electro-photographic photoreceptor having a support medium and a photosensitive layer. The photosensitive layer contains a hydroxygallium phthalocyanine crystal, and the hydroxygallium phthalocyanine crystal contains a compound A having a dipole moment magnitude of 3.6 D or more and an SP value SPA of 11.5 (cal / cm3)1 / 2 or more, and a compound B having a dipole moment magnitude of greater than 0 and less than or equal to 2.0 D as well as an SP value SPB of 9.5 (cal / cm3)1 / 2 or less.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an electrophotographic photoreceptor, a process cartridge having the electrophotographic photoreceptor, and an electrophotographic apparatus having the electrophotographic photoreceptor.Furthermore, the present invention relates to a method for producing hydroxygallium phthalocyanine crystals. [Background technology]

[0002] Currently, semiconductor lasers that are often used as image exposure means in the electrophotographic field have long oscillation wavelengths of 650 to 820 nm, and development is underway to develop electrophotographic photoreceptors that can reduce the absolute value of the potential of exposed areas to light of such long wavelengths. Phthalocyanine pigments are effective as charge generating substances for electrophotographic photoreceptors capable of lowering the absolute value of the potential of exposed areas to light in such a long wavelength region. In recent years, there has been an increasing demand for image stability in electrophotographic devices. In particular, with the increasing speed of electrophotographic devices, there is a strong demand for electrophotographic photoreceptors that are not affected by changes in humidity in the environment in which the electrophotographic device is used and have a stable exposed area potential, even in electrophotographic devices with high-speed printing processes. As an electrophotographic photoreceptor that has little change in exposed area potential in response to changes in humidity, an electrophotographic photoreceptor that uses V-type hydroxygallium phthalocyanine crystals as a charge generating material has been reported. For example, Patent Document 1 describes an electrophotographic photoreceptor using hydroxygallium phthalocyanine crystals containing a polar organic solvent such as N,N-dimethylformamide. Furthermore, Patent Document 2 describes an electrophotographic photoreceptor using hydroxygallium phthalocyanine crystals containing N-methylformamide as a polar organic solvent. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-331107 [Patent Document 2] JP 2016-161713 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors have investigated the change in exposed area potential with respect to changes in environmental humidity when the hydroxygallium phthalocyanine crystals containing the polar organic solvents described in Patent Documents 1 and 2 are used as charge generating materials for electrophotographic photoreceptors. As a result, while the absolute value of the exposed area potential is low, it cannot be said that the crystals have sufficient performance to meet the higher requirements for environmental stability required for electrophotographic devices in high-speed printing processes.

[0005] Therefore, the object of the present invention is to provide an electrophotographic photoreceptor that has a low absolute value of the potential of the exposed portion even in an electrophotographic device with a high-speed printing process, and is not affected by the humidity fluctuation of the environment in which the electrophotographic device is used, and has a highly stable potential of the exposed portion. Another object of the present invention is to provide a process cartridge having the electrophotographic photoreceptor and an electrophotographic device having the electrophotographic photoreceptor. Still another object of the present invention is to provide a method for producing hydroxygallium phthalocyanine crystals that, when used as a charge generating material for an electrophotographic photoreceptor, can reduce the absolute value of the potential of the exposed portion of the electrophotographic photoreceptor, and can stabilize the potential of the exposed portion of the electrophotographic photoreceptor without being affected by the humidity fluctuation of the environment in which the electrophotographic device equipped with the electrophotographic photoreceptor is used. [Means for solving the problem]

[0006] The above object can be achieved by the present invention as described below. That is, an electrophotographic photoreceptor according to one aspect of the present invention is an electrophotographic photoreceptor having a support and a photosensitive layer, the photosensitive layer contains hydroxygallium phthalocyanine crystals, The hydroxygallium phthalocyanine crystal is The magnitude of the dipole moment is 3.6D or more, and the SP value is SP A is 11.5(cal / cm 3 )1 / 2 Compound A, The magnitude of the dipole moment is greater than 0 and less than or equal to 2.0D, and the SP value is SP B is 9.5(cal / cm 3 ) 1 / 2 and Compound B, which is

[0007] Further, an electrophotographic photoreceptor according to another aspect of the present invention is an electrophotographic photoreceptor having a support and a photosensitive layer, the photosensitive layer contains hydroxygallium phthalocyanine crystals, The hydroxygallium phthalocyanine crystal is At least one compound A selected from the group consisting of N,N-dimethylformamide and N-methylformamide; and at least one compound B selected from the group consisting of toluene, ethyl acetate, and tetrahydrofuran.

[0008] Furthermore, a process cartridge according to another aspect of the present invention is characterized in that it integrally supports the above-mentioned electrophotographic photosensitive member and at least one means selected from the group consisting of a charging means, a developing means and a cleaning means, and is detachably attachable to the main body of the electrophotographic apparatus.

[0009] Further, an electrophotographic apparatus according to another aspect of the present invention comprises the above electrophotographic photoreceptor, as well as an exposure unit, a charging unit, a developing unit and a transfer unit.

[0010] In addition, a method for producing a hydroxygallium phthalocyanine crystal according to another embodiment of the present invention comprises the steps of: For hydroxygallium phthalocyanine pigments, The magnitude of the dipole moment is 3.6D or more, and the SP value is SP A is 11.5(cal / cm 3 ) 1 / 2 Compound A, The magnitude of the dipole moment is greater than 0 and less than or equal to 2.0D, and the SP value is SP Bis 9.5(cal / cm 3 ) 1 / 2 Compound B, which is and carrying out a dispersion treatment by a wet milling method. Effect of the Invention

[0011] According to the present invention, it is possible to provide an electrophotographic photoreceptor in which the absolute value of the exposed area potential is low even in an electrophotographic device with a high-speed printing process, and in which the exposed area potential is highly stable without being affected by fluctuations in humidity in the environment in which the electrophotographic device is used. [Brief description of the drawings]

[0012] [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

[0013] The present invention will be described in detail below with reference to preferred embodiments. When hydroxygallium phthalocyanine crystal is used as a charge generating material of an electrophotographic photoreceptor, the absolute value of the potential of the exposed portion of the electrophotographic photoreceptor can be reduced. On the other hand, as a result of the study by the present inventors, it has been found that when the humidity of the environment in which an electrophotographic device is used increases, the absolute value of the potential of the exposed portion of an electrophotographic photoreceptor using hydroxygallium phthalocyanine crystal as a charge generating material increases. The present inventors believe that the reason for this is that the separation efficiency of the charge pair generated by exposure decreases due to the adsorption of water molecules in the environment to the hydroxy group of the hydroxygallium phthalocyanine molecule constituting the hydroxygallium phthalocyanine crystal.

[0014] In addition, the present inventors compared the case where the hydroxygallium phthalocyanine crystal containing the polar organic solvent described in Patent Document 1 or 2 is used as the charge generating material of the electrophotographic photoreceptor with the above case where the hydroxygallium phthalocyanine crystal does not contain the polar organic solvent. As a result, it was found that the change in the exposed part potential due to the change in the humidity of the environment is small. When the hydroxygallium phthalocyanine crystal containing only the conventional highly polar compound is used as the charge generating material of the electrophotographic photoreceptor, the absolute value of the exposed part potential can be reduced. However, on the other hand, according to the study by the present inventors, it was found that the electrophotographic photoreceptor using the hydroxygallium phthalocyanine crystal according to the conventional technology cannot sufficiently suppress the change in the exposed part potential due to the change in the humidity of the environment.

[0015] It is presumed that the highly polar compound adsorbs water molecules instead of the hydroxy group of the hydroxygallium phthalocyanine molecule constituting the hydroxygallium phthalocyanine crystal, and suppresses the change in the separation efficiency of the charge pair. However, it is considered that the adsorption effect of water molecules is not fully exhibited even if the highly polar compound is contained alone in the hydroxygallium phthalocyanine crystal. As a result, even if the hydroxygallium phthalocyanine crystal containing only the highly polar compound is used as the charge generating material of the electrophotographic photoreceptor, the change in the potential of the exposed part due to the change in the humidity of the environment cannot be fully suppressed. Therefore, it is considered that it is insufficient to meet the higher demand for environmental stability of electrophotographic devices in recent years.

[0016] In order to solve the above problems that occurred in the conventional technology, the present inventors have conducted extensive research and have found the following. That is, when the hydroxygallium phthalocyanine crystal used in the photosensitive layer of an electrophotographic photoreceptor contains two or more compounds having specific physical properties, the problems in the conventional technology can be solved. In other words, it has been found that by using such a hydroxygallium phthalocyanine crystal, the absolute value of the potential of the exposed portion can be reduced, and the change in the potential of the exposed portion due to the change in environmental humidity can be significantly suppressed.

[0017] Based on the above findings, the present inventors have come up with the present invention as described below. That is, the electrophotographic photoreceptor according to the present invention is an electrophotographic photoreceptor having a support and a photosensitive layer, the photosensitive layer containing hydroxygallium phthalocyanine crystals, the hydroxygallium phthalocyanine crystals having a dipole moment of 3.6D or more and an SP value SP A is 11.5(cal / cm 3 ) 1 / 2 and a compound A having a dipole moment greater than 0 and less than or equal to 2.0D and an SP value SP B is 9.5(cal / cm 3 ) 1 / 2 and Compound B. In one embodiment of the electrophotographic photoreceptor according to the present invention, Compound A is at least one selected from the group consisting of N,N-dimethylformamide and N-methylformamide. Compound B is at least one selected from the group consisting of toluene, ethyl acetate, and tetrahydrofuran.

[0018] Furthermore, the process cartridge according to the present invention is characterized in that it integrally supports the above-mentioned electrophotographic photosensitive member and at least one means selected from the group consisting of a charging means, a developing means and a cleaning means, and is detachably attachable to the main body of the electrophotographic apparatus.

[0019] Further, an electrophotographic apparatus according to the present invention is characterized by comprising the above electrophotographic photoreceptor, an exposure means, a charging means, a developing means and a transfer means.

[0020] Furthermore, in the method for producing a hydroxygallium phthalocyanine crystal according to the present invention, the magnitude of the dipole moment of a hydroxygallium phthalocyanine pigment is 3.6D or more and the SP value SP A is 11.5(cal / cm 3 ) 1 / 2 and a compound A having a dipole moment greater than 0 and less than or equal to 2.0D and an SP value SP B is 9.5(cal / cm 3 ) 1 / 2The method is characterized in that it comprises adding Compound B, which is as follows:

[0021] The present inventors believe that the mechanism by which the above technical problems can be solved with such a configuration is as follows. As described above, when the hydroxygallium phthalocyanine crystal containing only the conventional highly polar compound is used as the charge generating material of the electrophotographic photoreceptor, the change in the potential of the exposed area caused by the change in the humidity of the environment cannot be sufficiently suppressed. The reason for this is considered as follows. It is presumed that the highly polar compound adsorbs water molecules instead of the hydroxy group of the hydroxygallium phthalocyanine molecule constituting the hydroxygallium phthalocyanine crystal, and suppresses the change in the separation efficiency of the charge pair. However, it is considered that the effect of adsorbing water molecules is not fully exhibited even if the highly polar compound is contained alone in the hydroxygallium phthalocyanine crystal.

[0022] In contrast, the present invention contains compound A as a highly polar compound and compound B as a low polar compound. Compound A has a dipole moment of 3.6D or more and an SP value SP A is 11.5(cal / cm 3 ) 1 / 2 Compound B has a dipole moment greater than 0 and less than or equal to 2.0 D, and an SP value SP B is 9.5(cal / cm 3 ) 1 / 2 The compound is as follows. When compound B, which has a small dipole moment, is mixed with compound A, compound B exerts the effect of suppressing the intrusion of water molecules and their adsorption to OH ligands. At the same time, since compound B has a different SP value from compound A, it is thought that compound A is localized closer to the OH ligands, and the effect of compound A, which adsorbs water molecules instead of the OH ligands, is more pronounced. From the above, it is believed that in the present invention, fluctuations in the potential of exposed areas caused by adsorption of water molecules to OH ligands can be more significantly suppressed compared to the conventional case in which a highly polar compound is used alone.

[0023] The components according to the present invention will now be described in more detail. [Electrophotographic photoreceptor] The electrophotographic photoreceptor according to the present invention has a support and a photosensitive layer. The method for producing the electrophotographic photoreceptor according to the present invention includes a method in which the coating liquid for each layer described below is prepared, coated in the desired order, and dried. 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. The support and each layer will be described below.

[0024] <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.

[0025] <Conductive layer> In the present invention, a conductive layer may be provided on the support. By providing the 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. The conductive particles may be made of a material such as metal oxide, metal, or carbon black. Examples of metal oxides include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, bismuth oxide, etc. Examples of metals include aluminum, nickel, iron, nichrome, copper, zinc, silver, etc. Among these, it is preferable to use metal 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. 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. Furthermore, when a metal oxide is used as the conductive particles, the 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.

[0026] 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 thickness of the conductive layer is preferably from 1 μm to 50 μm, and particularly preferably from 3 μm to 40 μm. 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.

[0027] <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 carboxyl group, a thiol group, a carboxylic anhydride group, and a carbon-carbon double bond group.

[0028] 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. When a metal oxide is used, 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. The undercoat layer may further contain an additive.

[0029] The 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.

[0030] <Photosensitive layer> The electrophotographic photoreceptor according to the present invention has a photosensitive layer on a support, a conductive layer or an undercoat layer. The photosensitive layer contains a hydroxygallium phthalocyanine crystal, and the hydroxygallium phthalocyanine crystal contains a compound A and a compound B. Compound A has a dipole moment of 3.6D or more and an SP value SP A is 11.5(cal / cm 3 ) 1 / 2Compound B has a dipole moment greater than 0 and less than or equal to 2.0 D, and an SP value SP B is 9.5(cal / cm 3 ) 1 / 2 The compound is: In the present invention, a hydroxygallium phthalocyanine crystal containing compound A and compound B means a hydroxygallium phthalocyanine crystal in which compound A and compound B are incorporated within the crystal.

[0031] SP value of compound A A and the SP value of compound B, SP B The difference ΔSP between the above values ​​and the above values, as defined by the following formula, is preferably 2.5 or more, and more preferably 3.0 or more. ΔSP=SP A -SP B

[0032] In addition, the mass ratio b / a of the compound B to the compound A in the hydroxygallium phthalocyanine crystal is preferably 5.0% or more and 50% or less, and more preferably 10% or more and 24% or less. In the hydroxygallium phthalocyanine crystal, the mass ratio a / p of the compound A to the entire hydroxygallium phthalocyanine crystal is preferably 0.50% or more and 3.50% or less, and more preferably 1.80% or more and 3.00% or less. In the hydroxygallium phthalocyanine crystal, the mass ratio b / p of the compound B to the entire hydroxygallium phthalocyanine crystal is preferably 0.10% or more and 2.00% or less, and more preferably 0.20% or more and 0.50% or less.

[0033] In the hydroxygallium phthalocyanine crystal, the mass ratios a / p and b / p of compound A and compound B relative to the entire hydroxygallium phthalocyanine crystal can be measured, for example, by nuclear magnetic resonance (NMR). In addition, by measuring a / p and b / p, the mass ratio b / a of compound B relative to compound A in the hydroxygallium phthalocyanine crystal can be calculated.

[0034] The compound A preferably has an amide group. In particular, the compound A is preferably at least one selected from the group consisting of N,N-dimethylformamide and N-methylformamide. For example, the compound A may be N,N-dimethylformamide or N-methylformamide. The compound A is more preferably N-methylformamide.

[0035] In addition, the compound B is preferably at least one selected from the group consisting of toluene, ethyl acetate, and tetrahydrofuran. For example, the compound B may be toluene, ethyl acetate, or tetrahydrofuran. Among them, the compound B is more preferably toluene.

[0036] The photosensitive layer of an electrophotographic photoreceptor is mainly classified into (1) a multi-layer type photosensitive layer and (2) a single-layer type photosensitive layer. (1) The multi-layer type photosensitive layer has a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. (2) The single-layer type photosensitive layer has a photosensitive layer containing both a charge generation material and a charge transport material.

[0037] (1) Laminated photosensitive layer The laminated type photosensitive layer has a charge generating layer and a charge transport layer.

[0038] (1-1) Charge generation layer The charge generating layer preferably contains a charge generating substance and a binder resin. In the present invention, the charge generating material comprises a hydroxygallium phthalocyanine pigment. Other charge generating materials that can be used in the present invention include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, phthalocyanine pigments, etc. Among these, azo pigments and phthalocyanine pigments are preferred. Among phthalocyanine pigments, oxytitanium phthalocyanine pigments and chlorogallium phthalocyanine pigments are preferred.

[0039] The hydroxygallium phthalocyanine pigment used as the charge generating material preferably has crystal grains of a crystal type that exhibits peaks at Bragg angles 2θ of 7.4°±0.3° and 28.2°±0.3° in an X-ray diffraction spectrum using CuKα radiation. The crystal particle size of the hydroxygallium phthalocyanine pigment preferably has a peak at 20 nm to 50 nm in the crystal particle size distribution measured using small angle X-ray scattering, and the half-value width of the peak is preferably 50 nm or less. When a dispersant is used in the milling treatment, the amount of the dispersant is preferably 10 to 50 times the phthalocyanine pigment by mass. Examples of the solvent to be used include amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylformamide, N-methylacetamide, and N-methylpropionamide, halogen solvents such as chloroform, ether solvents such as tetrahydrofuran, and sulfoxide solvents such as dimethyl sulfoxide. The amount of the solvent to be used is preferably 5 to 30 times the phthalocyanine pigment by mass.

[0040] In the present invention, the method for recovering and analyzing compound A and compound B from the electrophotographic photoreceptor is not particularly limited, but for example, they can be recovered and analyzed as follows. First, the photosensitive layer is dissolved using an organic solvent or the like. Then, hydroxygallium phthalocyanine crystals are recovered by a known method such as centrifugation. The recovered hydroxygallium phthalocyanine crystals can be subjected to analysis.

[0041] The method of qualitative analysis of Compound A and Compound B in the present invention is not particularly limited, but can be performed, for example, as follows: That is, the qualitative analysis can be easily performed by comparing the spectrum obtained by a known structural analysis method such as pyrolysis gas chromatography-mass spectrometry or nuclear magnetic resonance spectroscopy (NMR) with a known database.

[0042] In the present invention, whether or not the hydroxygallium phthalocyanine crystal contains compound A and compound B therein can be determined by subjecting the obtained phthalocyanine crystal to NMR measurement under the following conditions and analyzing the obtained data. (NMR measurement) Measuring instrument used: AVANCEIII 500 manufactured by BRUKER Measured nuclides: 1 H Solvent: Bisulfuric acid (D2SO4) Accumulation count: 2000

[0043] The powder X-ray diffraction measurement of the phthalocyanine pigment contained in the electrophotographic photoreceptor according to the present invention was carried out under the following conditions. (Powder X-ray diffraction measurement) Measuring equipment used: Rigaku Electric Co., Ltd., X-ray diffraction device RINT-TTRII X-ray tube:Cu X-ray wavelength: Kα1 Tube voltage: 50KV Tube current: 300mA Scan method: 2θ scan Scan speed: 4.0° / min Sampling interval: 0.02° Start angle 2θ: 5.0° Stop angle 2θ: 35.0° Goniometer: Rotor horizontal goniometer (TTR-2) Attachment: Capillary rotating sample stage Filter: None Detector: Scintillation counter Incident Monochrome: Use Slit: Variable slit (parallel beam method) Counter monochromator: Not used Divergence slit: open Divergence vertical limit slit: 10.00mm Scattering slit: open Receiving slit: open

[0044] In the present invention, the charge generating layer contains hydroxygallium phthalocyanine crystals produced from the hydroxygallium phthalocyanine pigment used as the charge generating material. The method for producing hydroxygallium phthalocyanine crystals according to the present invention comprises adding the above-mentioned compound A and the above-mentioned compound B to a hydroxygallium phthalocyanine pigment, and carrying out a dispersion treatment by a wet milling method. In the method for producing hydroxygallium phthalocyanine crystals according to the present invention, the mass ratio b2 / a2 of the amount of compound B added to compound A is preferably 2.6% or more and 26% or less. Here, the mass ratio b2 / a2 of the amount added refers to the ratio of the mass of compound B added to the hydroxygallium phthalocyanine pigment to the mass of compound A added to the hydroxygallium phthalocyanine pigment. The content of the charge generating material in the charge generating layer is preferably from 40% by mass to 85% by mass, and more preferably from 60% by mass to 80% by mass, based on the total mass of the charge generating layer.

[0045] Examples of the binder resin include polyester resin, polycarbonate resin, polyvinyl acetal resin, polyvinyl butyral resin, acrylic resin, silicone resin, epoxy resin, melamine resin, polyurethane resin, phenol resin, polyvinyl alcohol resin, cellulose resin, polystyrene resin, polyvinyl acetate resin, polyvinyl chloride resin, etc. Among these, polyvinyl butyral resin is more preferable. The charge generating layer may further contain additives such as an antioxidant and an ultraviolet absorbing agent, etc. Specific examples of such additives include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.

[0046] The thickness of the charge generating layer is preferably from 0.1 μm to 1 μm, and more preferably from 0.15 μm to 0.4 μm. The charge generating layer can be formed by preparing a coating solution for the charge generating layer containing the above-mentioned materials and solvent, forming a coating film 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.

[0047] (1-2) Charge transport layer The charge transport layer preferably contains a charge transport material and a binder resin. Examples of the charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these materials. Among these, in order to obtain the effects of the present application, it is preferable to use a material having an ionization potential of 5.2 eV or more and 5.4 eV or less. If the ionization potential of the charge transport material is 5.2 eV or more, α, which represents the electric field intensity dependency, does not become too large, and the deterioration of the memory phenomenon after repeated use can be suppressed, and if it is 5.4 eV or less, the increase in the residual potential can be suppressed. The ionization potential can be determined by measuring the threshold energy for emitting electrons using an atmospheric photoelectron spectrometer (product name: AC-2) manufactured by Riken Keiki Co., Ltd. The content of the charge transport material in the charge transport layer is preferably from 25% by weight to 70% by weight, and more preferably from 30% by weight to 55% by weight, based on the total weight of the charge transport layer.

[0048] Examples of the resin include polyester resin, polycarbonate resin, acrylic resin, polystyrene resin, etc. Among these, polycarbonate resin and polyester resin are preferable. As the polyester resin, polyarylate resin is particularly preferable. The content ratio (mass ratio) of the charge transport material to the resin is preferably from 4:10 to 20:10, and more preferably from 5:10 to 12:10.

[0049] The charge transport layer may also 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 thickness of the charge transport layer is preferably from 5 μm to 30 μm, more preferably from 8 μm to 17 μm, and particularly preferably from 10 μm to 14 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.

[0050] (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.

[0051] <Protective layer> In the present invention, a protective layer may be provided on the photosensitive layer. By providing the protective layer, durability can be improved. The protective layer preferably contains conductive particles and / or a charge transport material, and a binder resin. The conductive particles include particles of metal oxides such as titanium oxide, zinc oxide, tin oxide, and indium oxide. Examples of the charge transport material include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these materials. Among these, triarylamine compounds and benzidine compounds are preferred. Examples of the binder resin include polyester resin, acrylic resin, phenoxy resin, polycarbonate resin, polystyrene resin, phenol resin, melamine resin, epoxy resin, etc. Among them, polycarbonate resin, polyester resin, and acrylic resin are preferable. The protective layer may be formed as a cured film by polymerizing a composition containing a monomer having a polymerizable functional group. Examples of the reaction include thermal polymerization, photopolymerization, and radiation polymerization. Examples of the polymerizable functional group of the monomer having a polymerizable functional group include an acrylic group and a methacrylic group. A material having a charge transport function may be used as the monomer having a polymerizable functional group.

[0052] The protective layer may contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slipping agents, abrasion resistance improvers, etc. 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 thickness of the protective layer is preferably from 0.5 μm to 10 μm, and more preferably from 1 μm to 7 μm. The protective layer can be formed by preparing a coating solution for the protective layer containing the above-mentioned materials and solvent, forming a coating film from 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, sulfoxide-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0053] [Process cartridges, electrophotographic devices] The process cartridge according to the present invention is characterized in that it integrally supports the electrophotographic photosensitive member described above and at least one means selected from the group consisting of a charging means, a developing means and a cleaning means, and is detachably attachable to the main body of the electrophotographic apparatus. The electrophotographic apparatus according to the present invention is characterized by comprising the electrophotographic photosensitive member described above, an exposure means, a charging means, a developing means and a transfer means.

[0054] FIG. 1 shows an example of a schematic configuration of an electrophotographic apparatus having a process cartridge equipped with an electrophotographic photosensitive member. A cylindrical electrophotographic photoreceptor 1 is driven to rotate around an axis 2 at a predetermined peripheral speed in the direction of the arrow. The surface of the electrophotographic photoreceptor 1 is charged to a predetermined positive or negative potential by a charging means 3. Although the figure shows a roller charging method using a roller-type charging member, a corona charging method, a proximity charging method, an injection charging method, or other charging methods may be adopted. Exposure light 4 is irradiated from an exposure means (not shown) onto the charged surface of the electrophotographic photoreceptor 1, and an electrostatic latent image corresponding to the target image information is formed. The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed with toner contained in a 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 a transfer material 7 by a transfer means 6. The transfer material 7 to which the toner image has been transferred is transported to a fixing means 8, where the toner image is fixed, and the transfer material is printed out outside the electrophotographic device. The electrophotographic device may have a cleaning means 9 for removing deposits such as toner remaining on the surface of the electrophotographic photoreceptor 1 after transfer. The cleaning means 9 is preferably a cleaning blade having a urethane resin. Alternatively, a so-called cleanerless system may be used in which the deposits are removed by the developing means 5 or the like without providing a separate cleaning means 9. The electrophotographic apparatus may have a charge eliminating mechanism that eliminates charge on the surface of the electrophotographic photoreceptor 1 by pre-exposure light 10 from a pre-exposure means (not shown). Also, in order to mount and remove the process cartridge 11 according to one embodiment of the present invention to and from the main body of the electrophotographic image forming apparatus, a guide means 12 such as a rail may be provided. The electrophotographic photoreceptor according to the present invention can be used in electrophotographic image forming apparatuses such as laser beam printers, LED printers, copiers, facsimiles, and combination machines thereof. EXAMPLES

[0055] 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.

[0056] [Example 1] <Support> An aluminum cylinder (JIS-A3003, aluminum alloy) having a diameter of 24 mm and a length of 257 mm was used as a support (conductive support).

[0057] <Undercoat layer> The following materials were prepared: Rutile-type titanium oxide particles (average primary particle size: 150 nm, manufactured by Teika) 3 parts 4.5 parts N-methoxymethylated nylon (product name: Torezin EF-30T, manufactured by Nagase ChemteX) Copolymer nylon resin (product name: Amilan CM8000, manufactured by Toray) 1.5 parts These were added to a mixed solvent of 90 parts of methanol and 60 parts of 1-butanol to prepare a dispersion. This dispersion was dispersed for 6 hours in a vertical sand mill using glass beads with a diameter of 1.0 mm. The solution thus subjected to the sand mill dispersion treatment was then further dispersed for 1 hour in an ultrasonic disperser (UT-205, manufactured by Sharp) to prepare a coating solution for an undercoat layer. The output of the ultrasonic disperser was set to 100%. In addition, no media such as glass beads were used in this milling treatment. Next, the obtained coating liquid for undercoat layer was dip-coated onto the above-mentioned support to form a coating film, and the coating film was dried by heating at a temperature of 100° C. for 10 minutes to form an undercoat layer with a thickness of 2 μm.

[0058] <Charge generation layer> [Synthesis of Hydroxygallium Phthalocyanine Pigment] [Synthesis Example 1] In a nitrogen flow atmosphere, 5.46 parts of orthophthalonitrile and 45 parts of α-chloronaphthalene were added to a reaction vessel, and the vessel was heated to a temperature of 30°C and maintained at this temperature. Next, 3.75 parts of gallium trichloride were added at this temperature (30°C). The water concentration of the mixed liquid at the time of addition was 150 ppm. The temperature was then increased to 200°C. Next, the mixture was reacted at a temperature of 200°C for 4.5 hours under a nitrogen flow atmosphere, cooled, and the product was filtered when the temperature reached 150°C. The resulting filtrate was dispersed and washed using N,N-dimethylformamide at a temperature of 140°C for 2 hours, and then filtered. The resulting filtrate was washed with methanol and then dried to obtain a chlorogallium phthalocyanine pigment in a yield of 71%.

[0059] [Synthesis Example 2] 4.65 parts of the chlorogallium phthalocyanine pigment obtained in the above Synthesis Example 1 was dissolved in 139.5 parts of concentrated sulfuric acid at a temperature of 10°C, dropped into 620 parts of ice water under stirring to reprecipitate, and filtered under reduced pressure using a filter press. At this time, No. 5C (manufactured by Advantec Co., Ltd.) was used as the filter. The obtained wet cake (filtrate) was dispersed and washed with 2% ammonia water for 30 minutes, and then filtered using a filter press. Next, the obtained wet cake (filtrate) was dispersed and washed with ion-exchanged water, and then filtration using a filter press was repeated three times. Finally, freeze-drying was performed to obtain a hydroxygallium phthalocyanine pigment (hydrated hydroxygallium phthalocyanine pigment) with a solid content of 23% in a yield of 97%.

[0060] [Synthesis Example 3] 6.6 kg of the hydroxygallium phthalocyanine pigment obtained in Synthesis Example 2 above was dried using a Hyper Dry dryer (product name: HD-06R, frequency (oscillation frequency): 2455 MHz ± 15 MHz, manufactured by Japan Biocon) as follows. The hydroxygallium phthalocyanine pigment obtained in Synthesis Example 2 above was placed on a dedicated circular plastic tray in the form of a lump (water-containing cake thickness 4 cm or less) just removed from the filter press, and the far-infrared rays were turned off and the temperature of the inner wall of the dryer was set to 50° C. During microwave irradiation, the vacuum pump and leak valve were adjusted to adjust the degree of vacuum to 4.0 to 10.0 kPa. First, in the first step, the hydroxygallium phthalocyanine pigment was irradiated with 4.8 kW microwaves for 50 minutes, and then the microwaves were turned off and the leak valve was closed to create a high vacuum of 2 kPa or less. At this point, the solid content of the hydroxygallium phthalocyanine pigment was 88%. In the second step, the leak valve was adjusted to adjust the degree of vacuum (pressure inside the dryer) to within the above-mentioned set value (4.0 to 10.0 kPa). Thereafter, the hydroxygallium phthalocyanine pigment was irradiated with 1.2 kW microwaves for 5 minutes, and the microwaves were turned off and the leak valve was closed to create a high vacuum of 2 kPa or less. This second step was repeated once more (a total of two times). At this point, the solid content of the hydroxygallium phthalocyanine pigment was 98%. Furthermore, in the third step, microwave irradiation was performed in the same manner as in the second step, except that the microwave output in the second step was changed from 1.2 kW to 0.8 kW. This third step was repeated once more (a total of two times). In the fourth step, the leak valve was adjusted to restore the degree of vacuum (pressure inside the dryer) to the above-mentioned set value (4.0 to 10.0 kPa). After that, the hydroxygallium phthalocyanine pigment was irradiated with 0.4 kW microwaves for 3 minutes, and the microwaves were turned off and the leak valve was closed to create a high vacuum of 2 kPa or less. This fourth step was repeated seven more times (total of eight times). In total, 1.52 kg of hydroxygallium phthalocyanine pigment (crystals) with a moisture content of 1% or less was obtained over a total of three hours.

[0061] [Preparation example of coating solution 1 for charge generating layer] The following materials were prepared: 20 parts of the hydroxygallium phthalocyanine pigment obtained in Synthesis Example 3 above Compound A: 172 parts of N-methylformamide Compound B: 18 parts toluene These were subjected to wet milling treatment in a sand mill together with 300 parts of glass beads having an average particle size of 0.8 mm at 25±5°C for 70 hours. In this case, a 1L sand mill was used as the container, and the wet milling treatment was performed under the condition that the blade rotated 600 times per minute. Hydroxygallium phthalocyanine crystals were taken out from this dispersion using N-methylformamide, filtered, and the top of the filter was thoroughly washed with tetrahydrofuran. The filtered product was dried in a vacuum to obtain 18 parts of hydroxygallium phthalocyanine crystals. This hydroxygallium phthalocyanine crystal was a crystal that showed peaks at 7.4° and 28.3° in the X-ray diffraction pattern (Bragg angle 2θ±0.2°) using CuKα radiation. In addition, it was confirmed by NMR measurement that the hydroxygallium phthalocyanine crystal obtained in this example contained 2.00% by mass of N-methylformamide and 0.41% by mass of toluene, calculated from the proton ratio. Since both N-methylformamide and toluene are dissolved in tetrahydrofuran, which is the washing solvent, it is understood that N-methylformamide and toluene are contained in the hydroxygallium phthalocyanine crystal in this example. Next, the following materials were prepared: 20 parts of the hydroxygallium phthalocyanine crystal obtained above Polyvinyl butyral (product name: S-LEC BX-1, manufactured by Sekisui Chemical Co., Ltd.) 10 parts 190 parts cyclohexanone 482 pieces of glass beads with a diameter of 0.9 mm These were dispersed using a sand mill (K-800, manufactured by Igarashi Machinery Manufacturing (now Imex), disk diameter 70 mm, number of disks 5) for 4 hours under cooling water temperature of 18°C. The disks were rotated at 1,800 revolutions per minute. 444 parts of cyclohexanone and 634 parts of ethyl acetate were added to this dispersion to prepare coating solution 1 for charge generating layer. The coating solution 1 for charge generation layer obtained in the preparation example of the coating solution 1 for charge generation layer was dip-coated onto the above-mentioned 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 generation layer with a thickness of 0.2 μm.

[0062] <Charge transport layer> The following materials were prepared: As a charge transport material, 5 parts of a triarylamine compound represented by the following formula: [ka] As a charge transport material, 5 parts of a triarylamine compound represented by the following formula: [ka] Polycarbonate resin (product name: Iupilon Z-400, manufactured by Mitsubishi Engineering Plastics) 10 parts These were dissolved in a mixed solvent of 25 parts of ortho-xylene / 25 parts of methyl benzoate / 25 parts of dimethoxymethane to prepare a coating solution 1 for the charge transport layer. Next, the obtained coating liquid for the charge transport layer was dip-coated on the charge generating layer to form a coating film, and the coating film was dried at 120° C. for 30 minutes to form a charge transport layer having a thickness of 16 μm. By the above method, an electrophotographic photoreceptor 1 was produced.

[0063] [Charge generating layer coating liquid 2-35] In the preparation example of the coating liquid 1 for charge generation layer, the types of compound A and compound B and the contents in the crystal were changed to the substances and values ​​shown in Table 1. Otherwise, coating liquids 2 to 35 for charge generation layer were produced in the same manner as the coating liquid 1 for charge generation layer. The abbreviations for the types of Compound A and Compound B in Table 1 have the following meanings: NMF: N-methylformamide DMF: N,N-dimethylformamide EtOAc: ethyl acetate THF: tetrahydrofuran NMP: N-methyl-2-pyrrolidone W:Water In addition, the addition ratio (%) b2 / a2 in Table 1 indicates the ratio of the mass of compound B added to the hydroxygallium phthalocyanine pigment to the mass of compound A added to the hydroxygallium phthalocyanine pigment in preparing the coating liquid for the charge generating layer. In addition, in Table 1, b / a indicates the mass ratio of compound B to compound A in the hydroxygallium phthalocyanine crystal. In addition, in Table 1, a / p indicates the mass ratio of compound A to the entire hydroxygallium phthalocyanine crystal in the hydroxygallium phthalocyanine crystal. In addition, in Table 1, b / p indicates the mass ratio of compound A to the entire hydroxygallium phthalocyanine crystal in the hydroxygallium phthalocyanine crystal. The water content in the pigment in the coating liquid 35 for the charge generating layer was measured by the moisture vaporization Karl Fischer method as follows: First, 0.3 g of the pigment in the coating liquid 35 for the charge generating layer was heated to 180° C. in a moisture vaporizer (ADP-611, manufactured by Kyoto Electronics Manufacturing Co., Ltd.) to evaporate moisture. Next, the water content was determined by coulometric titration using a Karl Fischer reagent with a trace moisture measuring device (MKC-501, manufactured by Kyoto Electronics Manufacturing Co., Ltd.).

[0064] [Examples 2 to 32, Comparative Examples 1 to 3] An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the type of the charge generating layer coating liquid used to form the charge generating layer was changed as shown in Table 1.

[0065] [evaluation] Using the electrophotographic photoreceptors produced in Examples 1 to 32 and Comparative Examples 1 to 3, the environmental humidity dependency of the potential of the exposed portion was evaluated under the following conditions. The electrophotographic device used was a modified version of a Hewlett-Packard laser beam printer, product name HP LaserJet Enterprise Color M553dn. Specific modifications included changing the print process speed to 80 (sheets / min), adjusting and measuring the voltage applied to the charging roller, and adjusting and measuring the amount of image exposure light. The cartridge used for evaluation was a modified cartridge for a laser beam printer, product name HP LaserJet Enterprise Color M553dn, manufactured by Hewlett-Packard Co., Ltd. The specific modification involved attaching a potential probe (product name: model 6000B-8, manufactured by Trek Japan Co., Ltd.) to the development position so that the potential could be measured. First, the above electrophotographic device, the above cartridge, and the electrophotographic photosensitive members according to the examples and comparative examples were left in an environment of 23°C temperature and 50% RH for 24 hours or more, and then the electrophotographic photosensitive member was attached to the cartridge and installed in the electrophotographic device. Next, the potential of the exposed portion was measured under the following conditions: charging condition: the potential of the charged portion was −600 V, exposure condition: the amount of image exposure light was 0.4 μJ / cm 2 The resulting potential of the exposed portion was designated as V1. The above electrophotographic device, the above cartridge, and the electrophotographic photosensitive members of the Examples and Comparative Examples were left in an environment of 23°C temperature and 85% RH for 24 hours or more, and then the electrophotographic photosensitive member was attached to the cartridge and installed in the electrophotographic device. Next, the potential of the exposed part was measured under the same conditions as in the measurement of V1. The obtained potential of the exposed part was designated as V2. Finally, the change Δ in the potential of the exposed portion was calculated from the obtained V1 and V2 according to the following formula: Δ=|V2-V1| The results of the above evaluations performed using the electrophotographic photoreceptors produced in Examples 1 to 32 and Comparative Examples 1 to 3 are shown in Table 1. As can be seen from Table 1, in Examples 1 to 32, the absolute value of the exposed portion potential was low, and even if the humidity of the environment in which the electrophotographic apparatus is used increased, the fluctuation of the exposed portion potential was suppressed.

[0066] [Table 1]

[0067] Disclosure according to an embodiment of the present invention includes the following configurations and methods. (Configuration 1) An electrophotographic photoreceptor having a support and a photosensitive layer, the photosensitive layer contains hydroxygallium phthalocyanine crystals, The hydroxygallium phthalocyanine crystal is The magnitude of the dipole moment is 3.6D or more, and the SP value is SP A is 11.5(cal / cm 3 ) 1 / 2 Compound A, The magnitude of the dipole moment is greater than 0 and less than or equal to 2.0D, and the SP value is SP B is 9.5(cal / cm 3 ) 1 / 2 Compound B, which is 1. An electrophotographic photoreceptor comprising: (Configuration 2) The above SP A and the above SP B The difference ΔSP is 2.5 (cal / cm 3 ) 1 / 2 The electrophotographic photoreceptor according to Configuration 1, which is as described above. (Configuration 3) 3. The electrophotographic photoreceptor according to configuration 1 or 2, wherein a mass ratio b / a of the compound B to the compound A in the hydroxygallium phthalocyanine crystal is 5.0% or more and 50% or less. (Configuration 4) 4. The electrophotographic photoreceptor according to Configuration 3, wherein the mass ratio b / a is 10% or more and 24% or less. (Configuration 5) 5. The electrophotographic photoreceptor according to any one of configurations 1 to 4, wherein the mass ratio a / p of the compound A to the entire hydroxygallium phthalocyanine crystal in the hydroxygallium phthalocyanine crystal is 0.50% or more and 3.50% or less. (Configuration 6) 6. The electrophotographic photoreceptor according to Configuration 5, wherein the mass ratio a / p is 1.80% or more and 3.00% or less. (Configuration 7) 7. The electrophotographic photoreceptor according to any one of configurations 1 to 6, wherein the mass ratio b / p of the compound B to the entire hydroxygallium phthalocyanine crystal is 0.10% or more and 2.00% or less. (Configuration 8) 8. The electrophotographic photoreceptor according to claim 7, wherein the mass ratio b / p is 0.20% or more and 0.50% or less. (Configuration 9) 9. The electrophotographic photoreceptor according to any one of configurations 1 to 8, wherein the compound A has an amide group. (Configuration 10) 10. The electrophotographic photoreceptor according to any one of configurations 1 to 9, wherein the compound A is at least one selected from the group consisting of N,N-dimethylformamide and N-methylformamide. (Configuration 11) 11. The electrophotographic photoreceptor according to any one of configurations 1 to 10, wherein the compound B is at least one selected from the group consisting of toluene, ethyl acetate, and tetrahydrofuran. (Configuration 12) An electrophotographic photoreceptor having a support and a photosensitive layer, the photosensitive layer contains hydroxygallium phthalocyanine crystals, The hydroxygallium phthalocyanine crystal is At least one compound A selected from the group consisting of N,N-dimethylformamide and N-methylformamide; At least one compound B selected from the group consisting of toluene, ethyl acetate and tetrahydrofuran; 1. An electrophotographic photoreceptor comprising: (Configuration 13) An electrophotographic photoreceptor according to any one of Configurations 1 to 12, At least one means selected from the group consisting of a charging means, a developing means, and a cleaning means; and a process cartridge which is detachably mountable to a main body of an electrophotographic apparatus. (Configuration 14) 13. An electrophotographic apparatus comprising: an electrophotographic photoreceptor according to any one of Configurations 1 to 12; and at least one means selected from the group consisting of an exposure means, a charging means, a developing means, a transfer means, and a cleaning means. (Method 1) A method for producing hydroxygallium phthalocyanine crystals, comprising the steps of: For hydroxygallium phthalocyanine pigments, The dipole moment is 3.6D or more, and the SP value is 11.5 (cal / cm 3 ) 1 / 2 Compound A, The magnitude of the dipole moment is greater than 0 and less than or equal to 2.0D, and the SP value is 9.5 (cal / cm 3 ) 1 / 2 Compound B, which is and carrying out a dispersion treatment by a wet milling method. (Method 2) The method for producing hydroxygallium phthalocyanine crystals according to method 1, wherein a mass ratio b2 / a2 of the amount of compound B added to the amount of compound A is 2.6% or more and 26% or less. (Method 3) 3. The method for producing a hydroxygallium phthalocyanine crystal according to the method 1 or 2, wherein the compound A has an amide group. (Method 4) The method for producing hydroxygallium phthalocyanine crystals according to any one of Methods 1 to 3, wherein the compound A is at least one selected from the group consisting of N,N-dimethylformamide and N-methylformamide. (Method 5) The method for producing hydroxygallium phthalocyanine crystals according to any one of Methods 1 to 4, wherein the compound B is at least one selected from the group consisting of toluene, ethyl acetate, and tetrahydrofuran. [Explanation of symbols]

[0068] 1. Electrophotographic photoreceptor 2-axis 3. Charging means 4 Exposure light 5. Developing method 6 Transfer Method 7 Transfer material 8 Fixing Method 9 Cleaning Method 10 Pre-exposure light 11 Process cartridge 12 Guidance means

Claims

1. An electrophotographic photoreceptor having a support and a photosensitive layer, the photosensitive layer contains hydroxygallium phthalocyanine crystals, The hydroxygallium phthalocyanine crystal is The magnitude of the dipole moment is 3.6D or more, and the SP value SP Ａ is 11.5 (cal / cm ３ ) １／２ Compound A, The magnitude of the dipole moment is greater than 0 and less than or equal to 2.0D, and the SP value SP Ｂ is 9.5 (cal / cm ３ ) １／２ Compound B, 1. An electrophotographic photoreceptor comprising:

2. The SP Ａ and the SP Ｂ The difference ΔSP is 2.5 (cal / cm ３ ) １／２ The electrophotographic photoreceptor according to claim 1 .

3. 2. The electrophotographic photoreceptor according to claim 1, wherein a mass ratio b / a of said compound B to said compound A in said hydroxygallium phthalocyanine crystal is 5.0% or more and 50% or less.

4. The electrophotographic photoreceptor according to claim 3 , wherein the mass ratio b / a is 10% or more and 24% or less.

5. 2. The electrophotographic photoreceptor according to claim 1, wherein a mass ratio a / p of the compound A to the entire hydroxygallium phthalocyanine crystal in the hydroxygallium phthalocyanine crystal is 0.50% or more and 3.50% or less.

6. The electrophotographic photoreceptor according to claim 5 , wherein the mass ratio a / p is 1.80% or more and 3.00% or less.

7. 2. The electrophotographic photoreceptor according to claim 1, wherein a mass ratio b / p of the compound B to the entire hydroxygallium phthalocyanine crystal in the hydroxygallium phthalocyanine crystal is 0.10% or more and 2.00% or less.

8. The electrophotographic photoreceptor according to claim 7 , wherein the mass ratio b / p is 0.20% or more and 0.50% or less.

9. The electrophotographic photoreceptor according to claim 1 , wherein the compound A has an amide group.

10. 2. The electrophotographic photoreceptor according to claim 1, wherein the compound A is at least one selected from the group consisting of N,N-dimethylformamide and N-methylformamide.

11. 2. The electrophotographic photoreceptor according to claim 1, wherein the compound B is at least one selected from the group consisting of toluene, ethyl acetate, and tetrahydrofuran.

12. An electrophotographic photoreceptor having a support and a photosensitive layer, the photosensitive layer contains hydroxygallium phthalocyanine crystals, The hydroxygallium phthalocyanine crystal is At least one compound A selected from the group consisting of N,N-dimethylformamide and N-methylformamide; At least one compound B selected from the group consisting of toluene, ethyl acetate and tetrahydrofuran; 1. An electrophotographic photoreceptor comprising:

13. The electrophotographic photoreceptor according to any one of claims 1 to 12, At least one means selected from the group consisting of a charging means, a developing means, and a cleaning means; and a process cartridge which is detachably mountable to a main body of an electrophotographic apparatus.

14. 13. An electrophotographic apparatus comprising: the electrophotographic photoreceptor according to claim 1; and at least one unit selected from the group consisting of an exposure unit, a charging unit, a developing unit, a transfer unit, and a cleaning unit.

15. A method for producing hydroxygallium phthalocyanine crystals, comprising the steps of: For hydroxygallium phthalocyanine pigments, The magnitude of the dipole moment is 3.6 D or more, and the SP value is 11.5 (cal / cm ３ ) １／２ Compound A, The magnitude of the dipole moment is greater than 0 and less than or equal to 2.0 D, and the SP value is 9.5 (cal / cm ３ ) １／２ Compound B, and carrying out a dispersion treatment by a wet milling method.

16. The method for producing a hydroxygallium phthalocyanine crystal according to claim 15, wherein a mass ratio b2 / a2 of the amount of compound B added to the amount of compound A is 2.6% or more and 26% or less.

17. The method for producing a hydroxygallium phthalocyanine crystal according to claim 15 or 16, wherein the compound A has an amide group.

18. The method for producing a hydroxygallium phthalocyanine crystal according to claim 15 or 16, wherein the compound A is at least one selected from the group consisting of N,N-dimethylformamide and N-methylformamide.

19. 17. The method for producing hydroxygallium phthalocyanine crystals according to claim 15 or 16, wherein the compound B is at least one selected from the group consisting of toluene, ethyl acetate and tetrahydrofuran.

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