JP2009251283A - Method for manufacturing electrophotographic photoreceptor, electrophotographic photoreceptor, image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an electrophotographic photoreceptor, in which traces of sulfuric acid in anodic oxidation are thoroughly removed so that a sealer is allowed to penetrate even into the micropores in an alumite layer in pore sealing treatment. <P>SOLUTION: By using a washing and sealing apparatus shown in Fig.1, an aluminum support on which an anodic oxide film has been formed is washed with a supercritical fluid and subjected to pore sealing treatment with a supercritical fluid containing a sealer including a nickel compound such as nickel acetate or nickel fluoride to seal the pores in the anodic oxide film, and then a charge generating layer and a charge transport layer are stacked to obtain an electrophotographic photoreceptor. By this method, the occurrence of image defects such as fine black spots due to repeated use of a photoreceptor can be suppressed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing an electrophotographic photosensitive member, an electrophotographic photosensitive member, an image forming apparatus, and a process cartridge, and more particularly, to an electrophotographic photosensitive member in which a photosensitive layer is formed on an anodized film formed on an aluminum support. It relates to a manufacturing method.

  In recent years, in an image forming apparatus using an electrophotographic system, due to a demand for high image quality, an image is exposed to an electrophotographic photosensitive member having a uniform surface charge corresponding to a colored portion of an image, and the surface charge is lost to static. A developing method that forms an electrostatic latent image, forms a toner image on the electrostatic latent image of the exposed portion, and does not form a toner image on the unexposed portion, that is, a so-called reversal developing method is mainly used.

  There are two types of electrophotographic photoconductors: organic electrophotographic photoconductors and inorganic electrophotographic photoconductors. From the viewpoint of high productivity, ease of material design, and future prospects, organic photoconductors can be used for organic electrons. Photographic photoreceptors have been actively developed, and those in which a charge generation layer, a charge transport layer and the like are laminated on a support are generally used.

  When an organic electrophotographic photosensitive member (hereinafter, also simply referred to as an electrophotographic photosensitive member or a photosensitive member) is used for reversal development, image defects such as “black spots” and “background stains” in which toner locally adheres to a white background occur. It is known. This occurs due to local neutralization of the surface charge by charge injection from the conductive support.

  In order to prevent black spots and background stains generated during the reversal development, in Patent Document 1, a charge generation layer and charge transport are provided on an alumium support having an alumite layer formed by anodizing (electrolytic treatment) the surface. An electrophotographic photosensitive member having a photosensitive layer formed by sequentially laminating layers is disclosed in Patent Document 2 as an aluminum support having an alumite layer formed by anodizing, oxotitanyl phthalocyanine as a charge generating agent, and a charge transporting agent. An electrophotographic photoreceptor comprising a photosensitive layer containing a stilbene compound is proposed.

JP 2001-255679 A JP 11-282183 A

  However, in both Patent Documents 1 and 2, the alumite layer is washed with water at the time of the sealing treatment for sealing the micropores formed at the time of the electrolytic treatment, and then an aqueous solution containing a nickel compound such as nickel acetate or nickel fluoride is used. In order to use it, there are cases where removal of sulfuric acid marks during anodization remaining in the fine pores of the alumite layer is insufficient, and there is a problem that image defects such as fine black spots occur due to repeated use of the photoreceptor.

  The present invention has been made in consideration of the above circumstances, and it is possible to sufficiently remove sulfuric acid traces during anodization so that the sealing agent can penetrate into the fine pores of the alumite layer during the sealing process. It is an object of the present invention to provide a method for producing an electrophotographic photoreceptor.

  Another object of the present invention is to provide an electrophotographic photosensitive member capable of suppressing the occurrence of image defects such as minute black spots by repeatedly using the photosensitive member, an image forming apparatus and a process cartridge including the same. is there.

In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that after an anodic oxide film having a thickness of 2 μm to 10 μm is formed on an aluminum support, the anodic oxide film is subjected to sealing treatment, and thereafter In the method for producing an electrophotographic photosensitive member for forming a photosensitive layer on an anodized film,
In the sealing treatment, after an anodic oxide film is formed on the aluminum support, the anodic oxide film is immersed in at least one of a supercritical fluid and a subcritical fluid containing a sealing agent. The pores in the anodic oxide film are sealed in a temperature range of 90 ° C.

The invention of claim 2 is the method for producing an electrophotographic photosensitive member according to claim 1,
The sealing agent is a nickel compound.

The invention of claim 3 is the method for producing an electrophotographic photosensitive member according to claim 1 or 2,
The supercritical fluid or subcritical fluid is carbon dioxide.

According to a fourth aspect of the present invention, there is provided an electrophotographic photosensitive member in which a photosensitive layer is formed on an anodized film on an aluminum support.
The electrophotographic photosensitive member is manufactured by the method of manufacturing an electrophotographic photosensitive member according to any one of claims 1 to 3.

According to a fifth aspect of the present invention, there is provided an electrophotographic photosensitive member that forms an electrostatic latent image on a surface, and a developing device that supplies toner to the electrostatic latent image to convert the electrostatic latent image into a toner image. In the image forming apparatus,
The electrophotographic photoreceptor is the electrophotographic photoreceptor according to claim 4.

According to a sixth aspect of the present invention, in the image forming apparatus of the fifth aspect,
The image forming apparatus includes a plurality of developing devices and a plurality of electrophotographic photosensitive members that are paired with the developing devices, and each of the developing devices accommodates a different color toner and corresponds to each toner. To the electrophotographic photosensitive member to form toner images of different colors on the surfaces of the respective electrophotographic photosensitive members, and the developing device and the electrophotographic photosensitive member forming a pair transfer the transfer member onto which the toner image is transferred. It arrange | positions along the direction, It is characterized by the above-mentioned.

According to a seventh aspect of the present invention, there is provided a process cartridge in which an electrophotographic photosensitive member and at least one of a developing device, a cleaning device, and a charging device are integrally formed.
The electrophotographic photoreceptor is the electrophotographic photoreceptor according to claim 4.

  According to the present invention, the sealing treatment is performed by immersing the anodic oxide film in at least one of a supercritical fluid and a subcritical fluid containing a sealing agent after forming the anodic oxide film on the aluminum support. The pores in the anodic oxide film are sealed in a temperature range of 30 ° C. to 90 ° C., thereby sufficiently removing sulfuric acid traces during anodic oxidation. It is possible to provide a method for producing an electrophotographic photosensitive member capable of penetrating to the inside of the fine holes.

  According to the present invention, the electrophotographic photosensitive member is an electrophotographic photosensitive member manufactured by the method for manufacturing an electrophotographic photosensitive member according to any one of claims 1 to 3, thereby repeating the photosensitive member. It is possible to provide an electrophotographic photosensitive member capable of suppressing the occurrence of image defects such as fine black spots in both regular development and reversal development, and an image forming apparatus and process cartridge provided with the same. become.

  As a result of examining image defects such as “black spots” and “background stains” in an electrophotographic photosensitive member in which a photosensitive layer is formed on an anodized film on an aluminum support, the present inventors have found that the fine pores in the alumite layer It has been investigated that removal of sulfuric acid traces during the remaining anodization may be insufficient, and that image defects such as fine black spots occur due to repeated use of the photoreceptor.

  As a result of further investigation based on this investigation, after an anodic oxide film was formed on the aluminum support, sealing treatment was performed with a supercritical fluid containing a nickel compound (sealing agent) such as nickel acetate or nickel fluoride. After the pores in the anodic oxide film are sealed, an electrophotographic photosensitive member in which a charge generating layer, a charge transporting layer, and the like are laminated is used to generate image defects such as minute black spots due to repeated use of the photosensitive member. As a result, the present invention has been completed.

  First, the cleaning and sealing treatment of an anodized film formed on an aluminum support according to the present invention will be described.

  FIG. 1 shows a schematic configuration of a cleaning and sealing device using a supercritical fluid used for cleaning and sealing treatment in which an anodized film (alumite layer) is formed on an aluminum support according to an embodiment of the present invention. FIG.

  First, by using the cleaning and sealing apparatus shown in FIG. 1 according to the present embodiment, an anodized film (anodized film) is formed by so-called anodizing treatment in which an electroconductive aluminum support described later is subjected to electrolytic treatment in an acidic solution. The washing of acid traces such as sulfuric acid traces remaining on the aluminum support on which the layer) is formed will be described.

  As shown in FIG. 1, the aluminum support 61 after the etching process by anodizing is disposed in the pressure vessel 62, the valve 68, the three-way valves 70, 74 are adjusted, and the tank 69 is supercritical by the pump 69. It becomes possible to introduce the fluid or the subcritical fluid into the pressure-resistant vessel 62 and clean the aluminum support 61 appropriately. And by such washing | cleaning, the adhesiveness of the aluminum support body 61 and the photosensitive layer which provided the alumite layer which consists of aluminum oxide formed by the anodic oxidation can be improved.

Therefore, in the present invention, an aluminum support (drum) 61 in which an anodized layer is formed by anodization is disposed in the pressure-resistant vessel 62 in the same manner as described above, and the valves 68 and the three-way valves 70 and 74 are adjusted. A supercritical fluid or a subcritical fluid is introduced from the tank 67 into the pressure vessel 62 by the pump 69 to clean the aluminum support 61.
Subsequently, the supercritical fluid or subcritical fluid 75 in which the sealing agent is dispersed from the dispersion tank 65 is opened in the valve 71 and the three-way valve 74 and introduced into the pressure vessel 62 by the pump 72 to seal the aluminum support 61. It is immersed in the agent-dispersed supercritical fluid or the sealant-dispersed subsupercritical fluid. The dispersion tank 65 includes a stirrer 66, and the sealing agent is uniformly dispersed by stirring the sealing agent-dispersing supercritical fluid or subcritical fluid in the dispersion tank 65. The heater 73 heats the supercritical fluid or subcritical fluid in which the sealing agent is dispersed to 30 to 90 ° C. to perform sealing processing. After the sealing treatment, the pump 72 is reversed to discharge the coating liquid (supercritical fluid or subcritical fluid in which the sealing agent is dispersed) gradually out of the pressure vessel 62 and return to the dispersion tank 65 to support the aluminum. An alumite layer is formed by sealing the anodic oxide film on the body surface with a sealing agent.

  The alumite layer is formed by anodic oxidation. However, before the anodic oxidation treatment, it is desirable to perform the degreasing treatment by various degreasing cleaning methods such as acid, alkali, organic solvent, and surfactant. After that, it is preferable to perform a surface etching treatment with an alkali, acid, fluoride or the like.

The anodizing treatment is usually performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, boric acid, sulfamic acid, and the like, and an electrolytic treatment is carried out using a conductive aluminum support made of aluminum or an aluminum alloy as an anode, An alumite layer is formed on the support surface. In this case, either direct current or alternating current may be used, but the voltage is preferably ^{2 to} 160 V, the current density is 0.1 A / dm ^{2 to} 0.7 A / dm ² , and the liquid temperature is 10 to 40 ° C. The thickness of the anodized layer formed by sealing the anodic oxide film is preferably 2 to 10 μm, and more preferably 5 to 8 μm. If the thickness is less than 2 μm, the charging property is lowered and the local background contamination is likely to occur when the photoreceptor is used repeatedly. If the thickness exceeds 10 μm, the post-exposure potential is significantly increased during repeated use.

  FIG. 2 is a schematic perspective view showing the structure of an alumite layer formed by anodizing treatment, and FIG. 3 is a schematic cross-sectional view showing the structure of the anodized layer formed by anodizing treatment. The anodized aluminum support 15 has an alumite layer 16 formed on the surface thereof. As shown in FIGS. 2 and 3, the alumite layer 16 has a thin barrier layer 16a uniformly formed on the aluminum support 15, and a hexagonal prism having a honeycomb-like pore 16c on the upper layer. It has a porous layer 16b made of an assembly of cells 16d. The innumerable fine holes 16c are preferably subjected to a sealing treatment for the porous film.

  The sealing process is performed using the apparatus shown in FIG. Examples of the sealing agent include nickel compounds such as nickel acetate and nickel fluoride. These materials can be used alone or as a mixture of two or more.

  The supercritical fluid used in the present invention exists as a non-condensable high-density fluid in a temperature and pressure region that exceeds the limit (critical point) at which gas and liquid can coexist, and does not cause condensation even when compressed. As long as the fluid is at a temperature higher than the critical pressure or higher than the critical pressure, it is not particularly limited and can be appropriately selected according to the purpose. The subcritical fluid is not particularly limited as long as it exists as a high-pressure liquid in the temperature / pressure region near the critical point, and can be appropriately selected according to the purpose. Preferred examples of these fluids include carbon monoxide, carbon dioxide, ammonia, nitrogen, methanol, ethanol, ethane, propane, 2,3-dimethylbutane, benzene, chlorotrifluoromethane, dimethyl ether and the like. These supercritical fluids and subcritical fluids can be used alone or in combination of two or more. Among these, carbon dioxide is particularly preferable in that the critical temperature is close to room temperature and the handleability is excellent. In addition, an organic solvent (entrainer) that promotes dissolution of the sealing agent can be mixed with the supercritical fluid and the subcritical fluid. The entrainer is not particularly limited, such as hydrocarbon solvents such as hexane, cyclohexane and toluene, and ketone solvents such as acetone and methyl ethyl ketone.

  A supercritical fluid having a critical temperature of 30 ° C. to 40 ° C. and close to normal temperature, such as supercritical carbon dioxide and supercritical carbon monoxide, is desirably used at a temperature of 20 ° C. to 200 ° C. and a pressure of 5 MPa to 70 MPa. 30 ° C. to 90 ° C. and 7 MPa to 60 MPa are more preferable. Carbon dioxide and nitrous oxide are not preferred at temperatures below 20 ° C. and pressures below 5 MPa because carbon dioxide and nitrous oxide are unlikely to be in a supercritical state. If the temperature exceeds 150 ° C., the constituent material of the photoconductor may be dissolved, and if the pressure exceeds 70 MPa, the operation of the apparatus including the fluid pump may be hindered. Incidentally, the critical temperature of carbon dioxide is 31 ° C., the critical pressure is 7.53 MPa, the critical temperature of carbon monoxide is 37 ° C., and the critical pressure is 7.26 MPa.

  As shown in FIG. 4, the photosensitive layer according to the present invention has a laminated structure in which a charge generation layer 17 and a charge transport layer 18 are laminated on an alumite layer 16 formed on an aluminum support 15 and sealed. Further, if necessary, a protective layer is provided on the charge transport layer 18, an undercoat layer is interposed between the charge generation layer 17 and the alumite layer 16, or an intermediate between the charge generation layer 17 and the charge transport layer 18. A layer can also be interposed.

  As the aluminum support, aluminum containing 0.3 wt% or more of iron and copper as impurities, for example, aluminum made of JIS 3003, 5052, 6063, or the like is used. These aluminums contain 0.3 wt% or more of iron and copper in combination with less impurities such as JIS 1070, so that the mechanical strength is improved under the same heat treatment conditions, and the weight of the thin film can be reduced. .

  As the dimensional accuracy of the aluminum support, the total flare amount is preferably less than 0.05 mm. The total flare amount affects the gap accuracy between the photosensitive member and the developing means. When the total flare amount exceeds 0.05 mm, it is difficult to maintain the gap accuracy less than 0.1 mm. If the gap accuracy is 0.1 mm or more, there may be a variation in toner concentration in the longitudinal direction due to uneven wear. The surface roughness Rz of the aluminum support is preferably 0.05 μm to 1.5 μm in consideration of workability, moire due to reflection of the support, and the like. Since the surface is roughened by providing an alumite layer, moire is hardly generated even with a roughness close to a mirror surface.

  The charge generation layer is a layer mainly composed of a charge generation material, and a binder resin may be used as necessary. As the charge generation material, inorganic materials and organic materials can be used. Inorganic materials include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compounds and the like.

  On the other hand, a known material can be used as the organic material. For example, phthalocyanine pigments such as metal-free phthalocyanine and metal phthalocyanine, azulenium salt pigments, squaric acid methine pigments, azo pigments having a carbazole skeleton, azo pigments having a triphenylamine skeleton, azo pigments having a diphenylamine skeleton, dibenzothiophene skeleton Azo pigments having fluorenone skeleton, azo pigments having oxadiazole skeleton, azo pigments having bis-stilbene skeleton, azo pigments having distyryl oxadiazole skeleton, azo pigments having distyrylcarbazole skeleton, perylene Pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, Jigoido based pigments, and bisbenzimidazole pigments. These charge generation materials can be used alone or as a mixture of two or more. As an azo pigment, an azo pigment having a carbazole skeleton, an azo pigment having a triphenylamine skeleton, an azo pigment having a diphenylamine skeleton, an azo pigment having a dibenzothiophene skeleton, an azo pigment having a fluorenone skeleton, an azo pigment having an oxadiazole skeleton Pigments, azo pigments having a bis-stilbene skeleton, azo pigments having a distyryl oxadiazole skeleton, azo pigments having a distyryl carbazole skeleton, and phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine in addition to azo pigments, azulenium Salt pigment, square methine pigment, perylene pigment, anthraquinone or polycyclic quinone pigment, quinoneimine pigment, diphenylmethane and triphenylmethane pigment, benzoquinone and naphthoquinone pigment, Cyanine and azomethine pigments, indigoid pigments, may contain such one or more bis-benzimidazole pigments.

  Among these organic charge generating materials, titanyl phthalocyanine, particularly titanyl phthalocyanine having a maximum diffraction peak at a Bragg angle 2θ of 27.2 ± 0.2 ° with respect to the characteristic X-ray (wavelength 1.542α) of CuKα is highly sensitive. In particular, titanyl phthalocyanine is suitable in a high speed region where the process speed exceeds 1 m / sec.

  As a binder resin used as necessary for the charge generation layer, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, Polyacrylamide or the like is used. These binder resins can be used alone or as a mixture of two or more. Moreover, you may add a charge transport material as needed. In addition to the binder resin described above, a polymer charge transport material is preferably used as the binder resin for the charge generation layer. The ratio between the charge generation material and the resin of the charge generation layer is 1/1 to 10/1 in weight ratio, whereby the adhesion between the photosensitive layer and the undercoat layer can be improved and the post-exposure potential can be stabilized.

  As a method for forming the charge generation layer, a casting method from a solution dispersion system is mainly used. In order to provide a charge generation layer by the casting method, a ball mill, an attritor, or the like using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, butanone, or methyl ethyl ketone together with a binder resin, if necessary, the inorganic or organic charge generation material described above. It can be formed by dispersing with a sand mill or the like, and applying the solution after diluting the dispersion appropriately. The coating can be performed using a dip coating method, a spray coating method, a bead coating method, or the like. The thickness of the charge generation layer provided as described above is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm.

  The charge transport layer is a layer intended to hold a charged charge and to combine the charged charge generated and separated in the charge generation layer by exposure with the charged charge held. Furthermore, the charge transport layer is required to have a high electric resistance in order to achieve the purpose of holding the charged charge, and in order to achieve the purpose of obtaining a high surface potential with the held charged charge, the dielectric constant is small and Good charge mobility is required. The charge transport layer for satisfying these requirements is a coating solution in which a charge transport material and a binder resin are dissolved in a cyclic ether solvent such as tetrahydrofuran, tetrahydropyran, 1,4-dioxane, dioxolane, toluene, and dimethoxymethane. It is formed by coating. If necessary, an appropriate amount of a plasticizer, an antioxidant, a leveling agent and the like can be added in addition to the charge transport material and the binder resin. In terms of the environment, chlorinated solvents such as dichloromethane, chloroform, monochlorobenzene, trichloroethane, and trichloromethane are avoided. By using these cyclic ether solvents, the adhesion between the photosensitive layer and the support or the undercoat layer can be improved. The amount of residual cyclic ether solvent in the charge transport layer is preferably 20 ppm to 5000 ppm. If it is less than 20 ppm, the adhesiveness with the aluminum support or the undercoat layer is lowered, and if it exceeds 5000 ppm, the potential increases after exposure of the photoreceptor.

Examples of the charge transport material include a hole transport material and an electron transport material.
Examples of the electron transporting material include chloroanil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophene-4-one, 1,3,7-trinitro Examples thereof include electron accepting substances such as dibenzothiophene-5,5-dioxide. These electron transport materials can be used alone or as a mixture of two or more. In addition, antioxidants such as monophenolic compounds other than hydroquinone compounds, polymer phenolic compounds, paraphenylenediamines, and organic sulfur compounds may be used in combination. Specific examples of paraphenylenediamines, organic sulfur compounds, and organic adjacent compounds are as follows.

(Paraphenylenediamines)
N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'- Di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.
(Organic sulfur compounds)
Dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like.
(Organic phosphorus compounds)
Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.

  Examples of the hole transporting material include the electron donating materials shown below and are used favorably. For example, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline , Phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, thiophene derivatives, and the like. These hole transport materials can be used alone or as a mixture of two or more. The thickness of the charge transport layer is suitably about 5 to 100 μm.

  Binder resins that can be used in the charge transport layer include polycarbonate (bisphenol A type, bisphenol Z type), polyester, methacrylic resin, acrylic resin, polyethylene, vinyl chloride, vinyl acetate, polystyrene, phenol resin, epoxy resin, polyurethane, polychlorinated resin. Vinylidene, alkyd resin, silicone resin, polyvinyl carbazole, polyvinyl butyral, polyvinyl formal, polyacrylate, polyacrylamide, phenoxy resin, and the like are used. These binders can be used alone or as a mixture of two or more. The charge transport layer containing the binder resin may be mixed with a plasticizer, an antioxidant, or the like that plasticizes the binder resin. As the plasticizer, those used as plasticizers such as dibutyl phthalate, dioctyl phthalate and bisbenzylbenzene derivatives can be used as they are, and the amount used is about 0 to 30 parts by weight with respect to 100 parts by weight of the binder resin. Is appropriate.

  As the antioxidant, for example, the following monophenol compounds, bisphenol compounds, polymer phenol compounds, paraphenylenediamines, hydroquinones, organic sulfur compounds, and organic phosphorus compounds are suitable.

(Monophenol compound)
2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di-t-butyl-4 -Hydroxyphenyl) propionate, 3-t-butyl-4-hydroxynisol and the like.

(Bisphenol compounds)
2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2′-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4′-thiobis- ( 3-methyl-6-tert-butylphenol), 4,4′-butylidenebis- (3-methyl-6-tert-butylphenol) and the like.

(High molecular phenolic compounds)
1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t- Butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis (4 ′ -Hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, tocophenols and the like.

(Paraphenylenediamines)
N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'- Di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.

(Hydroquinones)
2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) ) -5-methylhydroquinone and the like.

(Organic sulfur compounds)
Dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like.

(Organic phosphorus compounds)
Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.

A leveling agent may be added to the charge transport layer coating solution. As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the chain are used, and the amount used is 100 parts by weight of binder resin. 0 to 1 part by weight is suitable.
A protective layer may be provided on the charge transport layer.

  The protective layer is a layer in which fine particles of metal or metal oxide are dispersed in a binder resin. As the binder resin, a resin that is transparent to visible and infrared light and excellent in electrical insulation, mechanical strength, and adhesiveness is desirable. As the binder resin for the protective layer, ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, poly Butylene terephthalate, polycarbonate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polychlorinated Examples thereof include resins such as vinylidene and epoxy resins. Examples of the metal oxide include titanium oxide, tin oxide, potassium titanate, TiO, TiN, zinc oxide, indium oxide, and antimony oxide. In addition to the protective layer, fluorine resins such as polytetrafluoroethylene, silicone resins, and those obtained by dispersing inorganic materials such as these resins can be added for the purpose of improving wear resistance. As a method for forming the protective layer, a normal coating method is employed. In addition, about 0.1-10 micrometers is suitable for the thickness of a protective layer.

  Next, an electrophotographic image forming apparatus according to an embodiment of the present invention will be described in detail with reference to FIGS. FIG. 5 is a schematic cross-sectional view showing a schematic configuration of an image forming unit for explaining the electrophotographic process and the image forming apparatus of the present invention, and FIG. 6 is a perspective view showing the relationship between the photoconductor and the charging roller in FIG. FIG. 7 is a schematic sectional view showing a schematic configuration of a tandem type image forming apparatus according to the present invention, and FIG. 8 is a schematic sectional view showing a process cartridge according to an embodiment of the present invention.

  The image forming unit of the image forming apparatus according to the embodiment of the present invention will be described with reference to FIG. In this embodiment, the image forming unit of the image forming apparatus has the charging roller 2, the developing device unit 4, the pre-transfer charger 26, the transfer charger 29, the separation charger 30, and the pre-cleaning charger 32 with the drum-shaped photoreceptor 1 as the center. , A fur brush 33, a cleaning blade 34, and a static elimination lamp 22 are provided. The photosensitive member 1 has a drum shape, but may be a sheet shape or an endless belt shape. The charging member, the pre-transfer charger 26, the transfer charger 29, the separation charger 30, and the pre-cleaning charger 32 are not only a corotron, a scorotron, a solid state charger (solid state charger), but also a roller-like charging member or a brush-like charging member. A member etc. are used and all well-known means can be used. In this embodiment, a charging roller 2 as shown in FIG. 6 is used.

  As the charging member, a non-contact charging method such as corona charging or a contact charging method using a charging member using a roller or a brush is generally used, and any of them can be used effectively in the present invention. In particular, the charging roller can significantly reduce the amount of ozone generated compared to corotron, scorotron, etc., and is effective in stability and prevention of image quality deterioration when the photoreceptor is used repeatedly. However, due to the contact between the photoconductor and the charging roller, the charging roller is contaminated by repeated use, which affects the photoconductor and contributes to the occurrence of abnormal images and reduced wear resistance. It was. In particular, when a photoconductor having high wear resistance is used, it is difficult to perform reface due to surface wear, and therefore it is necessary to reduce contamination of the charging roller.

  Therefore, as shown in FIG. 6, by attaching a gap forming member 2 a at positions opposite to the non-image forming area 1 a of the photosensitive member 1 at both ends of the charging roller 2 and bringing the gap forming member 2 a into contact with the surface of the photosensitive member 1, A gap G (see FIG. 5) having a predetermined length is formed on the photoreceptor 1. Then, by placing the charging roller 2 close to the photoreceptor 1 through the gap G, contaminants are less likely to adhere to the charging roller 2 or can be easily removed, and the influence thereof can be reduced. . In this case, the gap G between the photoreceptor 1 and the charging roller 2 is preferably small, and is 100 μm or less, more preferably 50 μm or less. However, by making the charging roller 2 non-contact, the discharge becomes non-uniform and the charging of the photosensitive member may become unstable. In that case, the stability of charging is maintained by superimposing the AC component on the DC component, thereby making it possible to simultaneously reduce the effects of ozone, charging roller contamination, and charging properties.

  For light sources such as image exposure L and static elimination lamp 22, light emitting materials such as fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light emitting diodes (LEDs), semiconductor lasers (LD), and electroluminescence (EL) are used. Can be used. Among these, a semiconductor laser (LD) and a light emitting diode (LED) are mainly used. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range. In addition to the steps shown in FIG. 5, these light sources and the like irradiate the photosensitive member with light by providing a transfer step, a static elimination step, a cleaning step, or a pre-exposure step that uses light irradiation. However, the exposure of the photoconductor in the static elimination step has a great influence of fatigue on the photoconductor, and may cause a decrease in charge and an increase in residual potential. Therefore, it may be possible to eliminate static electricity by applying a reverse bias in the charging process or cleaning process, instead of static elimination by exposure, which may be effective from the viewpoint of enhancing the durability of the photoreceptor.

  When the surface of the photosensitive member 1 is positively (negatively) charged by the charging roller 2 and the surface of the charged photosensitive member 1 is irradiated with exposure L corresponding to image information, the surface of the photosensitive member 1 is subjected to image information according to the image information. A positive (negative) electrostatic latent image is formed. To this electrostatic latent image, negative (positive) polarity toner (electric detection fine particles) having a polarity opposite to that of the surface of the photoreceptor 1 charged by the charging roller 2 from the developing device 4 is supplied. A positive image can be obtained by developing the toner image into a toner image, and a negative image can be obtained by developing the toner image with a positive (negative) polarity toner. A known method is applied to the developing unit, and a known method is also used for the charge eliminating unit.

  Generally, the above-mentioned charging member can be used as the transfer means, but the polarity opposite to that of the toner for effectively transferring the toner image on the photosensitive member 1 onto the transfer paper P as shown in FIG. It is effective to use a transfer charger 29 for applying a voltage of 2 and a separation charger 30 for applying a voltage in order to separate the transfer paper P from the photoreceptor 1.

  In this embodiment, such a transfer unit is used to directly transfer the toner image from the photosensitive member 1 to the transfer paper P. In the present invention, the toner image on the photosensitive member is once transferred intermediately. In the case of adopting an intermediate transfer system in which the image is transferred to a body and then transferred from the intermediate transfer body to paper, it is more preferable in terms of enhancing the durability or improving the image quality of the photoreceptor.

  Among the contaminants that adhere to the surface of the photoconductor, discharge substances generated by charging and external additives contained in the toner are easy to pick up the effects of humidity and cause abnormal images. One of the causative substances is paper dust generated from the transfer paper P. When they adhere to the photoreceptor, abnormal images are not only easily generated, but also wear resistance is reduced. There is a tendency to cause wear. Therefore, it is more preferable from the viewpoint of high image quality that the photoconductor and the paper are not in direct contact for the above reason.

  The intermediate transfer method is particularly effective for image forming apparatuses capable of full-color printing, and controls the prevention of color misregistration by forming a plurality of toner images on the intermediate transfer member and then transferring them to the paper at once. It is easy and effective for high image quality. However, the intermediate transfer method requires four scans to obtain one full-color image, so that the durability of the photoconductor has been a big problem. The photoconductor of the present invention is particularly effective and useful since it is easy to use in combination with an intermediate transfer type image forming apparatus because image blurring hardly occurs even without a drum heater. The intermediate transfer member includes various materials or shapes such as a drum shape and a belt shape. In the present invention, any conventionally known intermediate transfer member can be used. It is effective and useful for achieving high quality or high image quality.

  The toner developed on the photosensitive member 1 by the developing device unit 4 is transferred to the transfer paper P, but not all is transferred, and toner remaining on the photosensitive member 1 is also generated. Such toner is removed from the photoreceptor 1 by the fur brush 33 or the blade 34. This cleaning process may be performed only by the cleaning brush 33 or may be performed in combination with the blade 34. As the cleaning brush 33, a known brush brush or a mag fur brush is used. As described above, the cleaning is a process of removing toner remaining on the photosensitive member 1 after the transfer. However, the abrasion of the photosensitive member 1 is accelerated by repeatedly rubbing the photosensitive member 1 with the blade 34 or the brush 33 or the like. An abnormal image may occur due to damage or damage. Further, if the surface of the photoconductor 1 is contaminated due to poor cleaning, it not only causes an abnormal image, but also significantly reduces the life of the photoconductor 1. In particular, in the case of a photoreceptor having a layer containing a pigment for improving abrasion resistance on the outermost surface, contaminants attached to the surface of the photoreceptor are difficult to remove. It will promote the occurrence of. Therefore, improving the cleaning property of the photoconductor is very effective for improving the durability and image quality of the photoconductor.

  As means for improving the cleaning property of the photosensitive member, a method of reducing the coefficient of friction on the surface of the photosensitive member is known. Methods for reducing the coefficient of friction on the surface of the photoreceptor are classified into a method in which various lubricants are contained in the photoreceptor surface and a method in which the lubricant is supplied to the photoreceptor surface from the outside. The former is advantageous for small-diameter photoreceptors because of the high degree of freedom in layout around the engine, but the coefficient of friction increases remarkably with repeated use, and there remains a problem in its sustainability. On the other hand, the latter needs to be provided with a component for supplying a lubricating substance, but is effective for enhancing the durability of the photoreceptor because of high stability of the friction coefficient. Among them, the method of adhering to the photoreceptor during development by incorporating a lubricant into the developer is not restricted by the layout around the engine, and the effect of reducing the friction coefficient on the photoreceptor surface is high. Therefore, it is a very effective means for improving the durability and image quality of the photoreceptor.

  These lubricants include lubricating fluids such as silicone oil and fluorine oil, various fluorine-containing resins such as PTFE, PFA and PVDF, silicone resins, polyolefin resins, silicone grease, fluorine grease, paraffin wax, fatty acid esters , Fatty acid metal salts such as zinc stearate, lubricating liquids such as graphite and molybdenum disulfide, solids, powders, and the like, but particularly when mixed with a developer, it must be in the form of a powder, especially stearic acid Zinc has little adverse effect and can be used very effectively. When the zinc stearate powder is contained in the toner, it is necessary to consider the balance and influence on the toner, and the content is preferably 0.01 to 0.5% by weight with respect to the toner, preferably 0.1 to 0.3%. 3% by weight is more preferred.

  The photoconductor according to the present invention can be applied to a small-diameter photoconductor because it is a photoconductor excellent in durability by suppressing scumming and residual potential increase due to repeated use. Accordingly, as an image forming apparatus or a method thereof in which the above photoreceptor is used more effectively, each developing device corresponding to a plurality of color toners and a plurality of photoreceptors corresponding to these developing devices are provided. Accordingly, the image forming apparatus is extremely effectively used for a so-called tandem image forming apparatus that performs parallel processing. The tandem image forming apparatus includes a plurality of developing devices respectively storing at least four color toners of yellow (C), magenta (M), cyan (C), and black (K) that are required for full-color printing. A plurality of photoconductors paired with these developing devices are provided, and the paired developing devices and photoconductors are arranged in the transfer direction of a transfer body such as an intermediate transfer body or transfer paper. Then, each color toner from each developing device is supplied to a pair of photoconductors to form a toner image of each color on each photoconductor, and these toner images are sequentially superimposed and transferred to a transfer body. By doing so, it is possible to perform full color printing at an extremely high speed as compared with a conventional image forming apparatus capable of full color printing.

  FIG. 7 is a schematic cross-sectional view for explaining a tandem-type full-color electrophotographic image forming apparatus according to an embodiment of the present invention, and the following modifications also belong to the category of the present invention. In FIG. 7, reference numerals 1C, 1M, 1Y, and 1K are drum-shaped photoconductors, and the photoconductors are photoconductors according to the present invention. The photoreceptors 1C, 1M, 1Y, and 1K rotate in the direction of the arrow in the figure, and at least around them, charging rollers 2C, 2M, 2Y, and 2K, developing devices 4C, 4M, 4Y, and 4K, and a cleaning device 5C. , 5M, 5Y, 5K are arranged. The charging rollers 2C, 2M, 2Y, and 2K are charging members that constitute a charging device for uniformly charging the surfaces of the photoreceptors 1C, 1M, 1Y, and 1K.

  The photosensitive member between the charging members 2C, 2M, 2Y, and 2K and the developing devices 4C, 4M, 4Y, and 4K is irradiated with laser beams LC, LM, LY, and LK from an exposure member (not shown), and the photosensitive member 1C, Electrostatic latent images corresponding to the respective color images are formed on 1M, 1Y, and 1K. Then, four image forming elements 6C, 6M, 6Y, and 6K centering around the photoreceptors 1C, 1M, 1Y, and 1K are juxtaposed along the intermediate transfer conveyance belt 10 that is a transfer body conveyance unit. . The intermediate transfer conveyance belt 10 includes photosensitive members 1C, 1M, 1Y, and 1K between the developing devices 4C, 4M, 4Y, and 4K of the image forming units 6C, 6M, 6Y, and 6K and the cleaning members 5C, 5M, 5Y, and 5K. The transfer brushes 11 </ b> C, 11 </ b> M, 11 </ b> Y, and 11 </ b> K for applying a transfer bias are disposed on the back surface of the intermediate transfer conveyance belt 10. Each of the image forming elements 6C, 6M, 6Y, and 6K is different in the color of the toner inside the developing device, and has the same configuration.

  In the color electrophotographic apparatus having the configuration shown in FIG. 7, the image forming operation is performed as follows. First, in each of the image forming elements 6C, 6M, 6Y, and 6K, the photoreceptors 1C, 1M, 1Y, and 1K are charged by the charging rollers 2C, 2M, 2Y, and 2K that rotate in the direction of the arrow (the direction around the photoreceptor). Next, an electrostatic latent image corresponding to each color image to be created is formed by laser light LC, LM, LY, and LK at an exposure unit (not shown) disposed outside the photoreceptor.

  Next, toner of each color is supplied to the electrostatic latent images corresponding to the respective colors formed on the photoreceptors 1C, 1M, 1Y, and 1K by the developing devices 4C, 4M, 4Y, and 4K. The electrostatic latent image is developed to form a toner image. The developing devices 4C, 4M, 4Y, and 4K are developing devices that perform development with toners of C (cyan), M (magenta), Y (yellow), and K (black), respectively, and the four photosensitive members 1C, 1M, and 1Y. , 1K toner images of respective colors are superimposed on the transfer paper P. The transfer paper P is sent out from the tray by the paper supply roller 8, temporarily stopped by the pair of registration rollers 9, and sent to the intermediate transfer conveyance belt 10 in synchronization with the image formation on the photosensitive member. The transfer paper P held on the intermediate transfer transport belt 10 is transported, and each color toner image is transferred at the contact position (transfer section) with each of the photoreceptors 1C, 1M, 1Y, 1K. The toner image on the photoconductor is transferred onto the transfer paper P by an electric field formed by a potential difference between the transfer bias applied to the transfer brushes 11C, 11M, 11Y, and 11K and the photoconductors 1C, 1M, 1Y, and 1K. The Then, the transfer paper P on which the four color toner images are superimposed after passing through the four transfer portions is conveyed to the fixing device 12, where the toner is fixed, and is discharged to a paper discharge portion (not shown). Further, the residual toner remaining on the photoreceptors 1C, 1M, 1Y, and 1K without being transferred by the transfer unit is collected by the cleaning devices 5C, 5M, 5Y, and 5K.

In the example of FIG. 7, the image forming elements 6C, 6M, 6Y, and 6K are C (cyan), M (magenta), Y (yellow), and K (black) from the upstream side to the downstream side in the transfer sheet conveyance direction. ) Are arranged in the order of colors. However, the order is not limited to this order, and the color order is arbitrarily set. Further, when a black-only document is created, it is particularly effective to use the present invention to provide a mechanism that stops the image forming elements 6C, 6M, 6Y other than black. Further, in FIG. 7, the charging rollers 2C, 2M, 2Y, and 2K are in contact with the photoreceptors 1C, 1M, 1Y, and 1K, but by using a charging mechanism as shown in FIG. Gap (10
(About 200 μm) can reduce the amount of wear of both, and can reduce the amount of toner filming on the charging member and can be used satisfactorily.

  The image forming apparatus as described above may be fixedly incorporated in a copying apparatus, a facsimile machine, or a printer. However, each of the image forming elements 6C, 6M, 6Y, and 6K is in the form of a process cartridge. It may be incorporated within. A process cartridge is a single device (part) that contains a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a neutralizing unit, and the like.

  The above-described tandem image forming apparatus can transfer a plurality of toner images at a time, so that high-speed full-color printing is realized. However, since at least four photoconductors are required, an increase in the size of the apparatus is unavoidable, and depending on the amount of toner used, there is a difference in the wear amount of each photoconductor, thereby reproducing the color. There are many problems such as a decrease in performance and occurrence of abnormal images. On the other hand, the photoconductor according to the present invention can be applied even to a small-diameter photoconductor because of high durability, and the influence of increase in residual potential and background contamination is reduced. Even if the amount is different, the difference in residual potential and sensitivity over time is small, and a full color image having excellent color reproducibility can be obtained even when used repeatedly over a long period.

  The above illustrated electrophotographic process exemplifies an embodiment of the present invention, and of course, other embodiments are possible. The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge. A process cartridge is a single device (part) that contains a photosensitive member and includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit. There are many shapes and the like of the process cartridge, but a general example is shown in FIG. That is, the developing roller that agitates and conveys the toner contained in the housing 4b around the photosensitive member 1 and the developing roller that agitates and conveys the toner that is conveyed by the conveying screw 4c and supplies the toner to the photosensitive member 1 A developing device 4 having 4 a, a charging roller 2, and a cleaning device 5 having a cleaning blade 34 for scraping off toner remaining on the surface of the photoreceptor 1 are configured integrally with the photoreceptor 1. Then, these component parts can be integrally detached from the image forming apparatus, and repair, inspection, replacement, etc. of these component parts are removed from the image forming elements 6C, 6M, 6Y, 6K as necessary. It is possible to perform in the state. In this case, as the process cartridge, the developing device 4, the charging roller 2 and the cleaning device 5 do not always have to be integrated with the photosensitive member 1, and the developing device unit 4, the charging roller 2 and the cleaning device 5 are provided as necessary. At least one component and the photosensitive member 1 can be integrated, but in the present invention, at least the developing device unit 4 and the photosensitive member that form a toner image on the photosensitive member 1 are provided. A process cartridge integrated with 1 is preferable. In FIG. 8, reference numeral 19 denotes a transfer roller for transferring the toner image formed on the photosensitive member 1 to the transfer paper P conveyed by the registration roller 19.

  Next, a specific configuration and manufacturing method of the photoreceptor according to the present invention will be described based on examples. In the following examples, “parts” means parts by weight.

[Example 1]
The surface of a cylindrical aluminum support having a diameter (φ) of 30 mm × length (L) of 256 mm, a thickness of 0.75 mm, a surface roughness Rz: 0.8 μm and a total flare amount of 0.03 mm is degreased and washed, and the following bath composition And it was immersed for 5 minutes in the conditions, and the etching process was performed.

Sodium hydroxide 5%
Sodium fluoride 2%
Distilled water remainder Bath temperature 60 ℃

Thereafter, washing with water was repeated. Next, anodization was performed using a 15% sulfuric acid electrolyte (dissolved aluminum concentration 5 g / l) at a bath temperature of 21 ° C. and a direct current density of 1.5 A / dm ² .

  Next, using the cleaning and sealing apparatus shown in FIG. 1, cleaning was performed by immersion in a supercritical carbon dioxide fluid at 35 ° C. and 8 MPa for 15 minutes. Subsequently, 1 L (1 liter) was immersed in and brought into contact with a supercritical carbon dioxide fluid containing 15 g of nickel acetate and 5 g of boric acid at a temperature of 80 ° C. and 15 MPa for 1 hour to seal micropores in the anodized film. Thereafter, the pressure is reduced to 10 MPa while maintaining the temperature of 80 ° C., and the carbon dioxide fluid is allowed to flow for 30 minutes at a flow rate of 8 L / min using the pressurizing pump and the exhaust pressure valve while maintaining this pressure. The sealing agent that was not injected into the fine holes of the anodized film was removed from the pressure cell. After the removal, the temperature and pressure were gradually lowered to an atmospheric pressure atmosphere to form an alumite layer in which the anodized film on the surface of the aluminum support was sealed with nickel acetate. After the sealing treatment, the thickness of the alumite layer was 5.5 μm.

  Prior to the formation of the photosensitive layer, the valve 68 and the three-way valves 70 and 74 are adjusted, and a supercritical carbon dioxide fluid at 35 ° C. and 8 MPa is introduced from the tank 67 into the pressure-resistant vessel 62 by the pump 69, so that the aluminum support 1 Was washed for 30 minutes.

  Thus, an electrophotographic photosensitive member was prepared by forming a charge generation layer and a charge transport layer as follows on the alumite layer whose surface was sealed.

[Formation of charge generation layer]
A mixture of 2 parts of the charge generation material of the chemical formula (1), 60 parts of polyvinyl butyral resin (BX-1; manufactured by Sekisui Chemical Co., Ltd.) / Methyl ethyl ketone solution with a solid content concentration of 2 wt% is placed in a ball mill pot and a YTZ ball having a diameter of 2 mm is used. The charge generation layer coating solution was prepared by ball milling for 24 hours. This coating solution was dip-coated on the undercoat layer and dried at 95 ° C. for 20 minutes to form a charge generation layer having a thickness of 0.1 μm. The charge generation material of the chemical formula (1) had a peak at 27.2 ° by X-ray diffraction measurement.

[Formation of charge transport layer]
Next, a charge transport layer coating solution is prepared according to the following composition, and this coating solution is dip coated on the charge generation layer formed above, dried at 135 ° C. for 25 minutes, and a charge transport layer having a thickness of 32 μm. Formed.

<Composition of coating solution for charge transport layer>
Charge transport material of the following chemical formula (2) (manufactured by Ricoh) 7 parts Polycarbonate resin (TS-2050: manufactured by Teijin Chemicals) 10 parts Silicone oil (KF-50: manufactured by Shin-Etsu Chemical) 0.002 parts Tetrahydrofuran (Kanto Chemical) 77.4 parts)

[Example 2]
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the film thickness of the alumite layer after the sealing treatment was changed to 8 μm in Example 1.

Example 3
An electrophotographic photosensitive member was prepared in exactly the same manner as in Example 1 except that nickel acetate used in the sealing treatment in Example 1 was changed to nickel fluoride.

Example 4
After anodizing and washing with water on the aluminum support in the same manner as in Example 1, sealing treatment was performed in supercritical carbon dioxide as in Example 1. Thereafter, it was sufficiently washed with water and dried naturally to form an alumite layer having a thickness of 5.5 μm. Subsequently, a charge generation layer and a charge transport layer were provided in the same manner as in Example 1 to form an electrophotographic photoreceptor.

[Comparative Example 1]
An electrophotographic photoreceptor was prepared in exactly the same manner as in Example 1 except that the thickness of the alumite layer in Example 1 was changed to 12 μm.

[Comparative Example 2]
An electrophotographic photosensitive member was prepared in exactly the same manner as in Example 1, except that the thickness of the alumite layer in Example 1 was 1.5 μm.

[Comparative Example 3]
An electrophotographic photosensitive member was prepared in exactly the same manner as in Example 1 except that the temperature during the sealing treatment in Example 1 was changed to 120 ° C.

[Comparative Example 4]
An electrophotographic photosensitive member was prepared by providing a photosensitive layer in the same manner as in Example 1 except that the sealing treatment was not performed in Example 1.

[Comparative Example 5]
Etching treatment, anodization, and cleaning with supercritical carbon dioxide were performed in exactly the same manner as in Example 1, and then 5 g of nickel acetate and 5 g of boric acid were dissolved in 1 liter of distilled water and kept at a bath temperature of 100 ° C. for 25 minutes. It was immersed and sealed. Thereafter, cleaning with supercritical carbon dioxide was performed to form a 5.5 μm alumite layer. Subsequently, a charge generation layer and a charge transport layer were provided in the same manner as in Example 1 to prepare an electrophotographic photosensitive member.

[Comparative Example 5]
Etching, anodic oxidation, and cleaning with supercritical carbon dioxide were performed in exactly the same manner as in Example 1, and then a charge generation layer and a charge transport layer were provided in the same manner as in Example 1 without providing an alumite layer. A photoreceptor was formed.

  Images were formed using the electrophotographic photoreceptors prepared in the above examples and comparative examples. The toner, carrier and developer used in image formation were prepared as follows.

[Production of toner]
(Synthesis example of polyester resin)
In a four-necked separable flask with a stirrer, thermometer, nitrogen inlet, flow-down condenser, and condenser, 740 g of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxy Esterification catalyst of 300 g of ethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 466 g of dimethyl terephthalate, 80 g of isododecenyl succinic anhydride, and 114 g of tri-n-butyl 1,2,4-benzenetricarboxylate Added with. Under a nitrogen atmosphere, the temperature was raised to 210 ° C. in the first half, and the reaction was allowed to proceed with stirring at 210 ° C. under reduced pressure in the second half. A polyester resin having an acid value of 2.3 KOH mg / g, a hydroxyl value of 28.0 KOH mg / g, a softening point of 106 ° C., and a Tg of 62 ° C. was obtained.

(Example of base toner production)
Composition Binder resin: Polyester resin 85.6 parts Colorant: Carbon black 8.6 parts Charge control agent: Zinc compound of salicylic acid 0.9 part Mold release agent: Carnauba wax 4.3 parts A base toner was prepared according to the procedure described in 1. to obtain a black base toner having a volume average particle size of 6.8 μm.
Procedure 1. The raw materials having the above composition are mixed with a Henschel mixer.
Procedure 2. Melt-knead by Busconyder (Bus Co.) set at 120 ° C.
Procedure 3. After cooling the kneaded product, it is pulverized by a pulverizer using a turbo mill (manufactured by Turbo Kogyo Co., Ltd.).
Procedure 4. Classify using an air classifier.

(Product toner production example)
To the base toner obtained in the base toner production example, 1.5% by weight of silica (AEROSILTT 600: manufactured by Nippon Aerosil Co., Ltd.) and 0.7% by weight of titanium oxide (MT-150M: manufactured by Teica) were added. The mixture was mixed at 1000 rpm for 10 minutes with a Henschel mixer (manufactured by Mitsui Miike), and passed through a sieve having an opening of 50 μm to obtain an electrophotographic toner.

(Example of carrier production)
100 g of toluene was added to 100 g of a silicone resin (Toray Dow Corning Silicone: SR-2411) to prepare a coating solution. This solution is spray-coated on 1 kg of a carrier core material (average particle size 60 μm Cu—Zn ferrite) by a fluidized bed coating method, dried for about 5 minutes, heated at 200 ° C. for 1 hour, cooled and sieved with a sieve. Manufactured carrier. When coating by changing the average particle diameter of the carrier, the amount of silicone resin was adjusted by converting the surface area in order to keep the film thickness constant.

(Developer production example)
A developer was prepared by mixing 4 parts of the electrophotographic toner and 96 parts of the carrier with a tumbler mixer for 10 minutes.

  Four electrophotographic photoreceptors thus prepared were attached to a reverse development Ricoh digital color printer IPSIO SP C411. The initial charging potential VD and the post-exposure potential VL were measured with a unit to which the developing roller was removed and an electrometer probe was attached.

  Next, a developing roller was attached and 30,000 sheets were printed repeatedly in A4 vertical size to evaluate image quality (reproducibility of fine black spots and fine lines), charging potential VD, and post-exposure potential VL. Subsequently, 10,000 sheets were continuously printed in an environment of 30 ° C. and 90% RH, and then image quality (reproducibility of fine black spots and fine lines), charging potential VD, and post-exposure potential VL were measured.

  These results are shown in FIG. The reproducibility of the fine line was evaluated by printing a 1-dot oblique line. Table 1 shows the evaluation criteria for the reproducibility of the thin lines.

In addition, the evaluation of black spots was performed by measuring the size and number of black spots using a color image processor SPICCA (manufactured by Nippon Avionics Co., Ltd.), and determining the number of black spots with a diameter of 0.05 mm or more per 1 cm ² . Table 2 shows the criteria for black spot evaluation. In the determination, “○”, “◯”, “Δ” means that there is no practical problem, and “x” means that it is not suitable for practical use.

  As is apparent from the evaluation results shown in FIG. 9, when the charge generation layer and the charge transport layer are formed without forming the alumite layer shown in Comparative Example 6, a minute black spot is generated at the initial stage and practically used. If the sealing process is not performed and the sealing process is not performed as shown in Comparative Example 4, a large number of small black spots are generated after printing on 30,000 sheets, which is not practical. In addition, when the sealing agent shown in Comparative Example 5 was dissolved in distilled water and subjected to sealing treatment, the 30,000 black fine spots after printing were lower than in the initial case, and further 30 ° C. The fine line reproducibility also decreases after printing 10,000 sheets at 90% RH.

  On the other hand, in Examples 1 to 3 according to the present invention, the fine black spot characteristics after printing 30,000 sheets, the black spot characteristics after printing 10,000 sheets at 30 ° C. and 90% RH, and fine line reproducibility are also good. It is clear that the characteristic is shown. However, in the case of cleaning with supercritical carbon dioxide as shown in Example 4 and water washing after sealing treatment in supercritical carbon dioxide, minute black spots are slightly generated after printing 10,000 sheets at 30 ° C. and 90% RH. Although it is recognized that this occurs, it exhibits better black spot characteristics than Comparative Examples 4 and 5. From the results of Example 4, it is clear that cleaning with supercritical carbon dioxide and cleaning with supercritical carbon dioxide after sealing treatment in supercritical carbon dioxide are more preferable as in Examples 1-3. It is.

  As shown in Comparative Examples 1 and 2, when the thickness of the alumite layer deviates from the range of 12 μm, 1.5 μm, and 2 μm to 10 μm, fine line reproduction after printing 10,000 sheets at 30 ° C. and 90% RH Therefore, the thickness of the alumite layer is preferably in the range of 2 μm to 10 μm.

  Moreover, as shown in Comparative Example 3, when the sealing process is performed at a temperature of 120 ° C., microcracks are generated in the alumite layer, so that the sealing process is performed within the range of 30 ° C. to 90 ° C. Is preferred.

It is sectional drawing which showed schematic structure of the washing | cleaning and sealing apparatus which concerns on one Embodiment by this invention. It is a schematic perspective view which shows the structure of the alumite layer formed by the anodizing process which concerns on one Embodiment by this invention. It is a schematic sectional drawing which shows the structure of the alumite layer formed by the anodizing process which concerns on one Embodiment by this invention. 1 is a schematic cross-sectional view of a photoreceptor according to an embodiment of the present invention. 1 is a schematic cross-sectional view illustrating a schematic configuration of an image forming unit for explaining an electrophotographic process and an image forming apparatus of the present invention. FIG. 6 is a perspective view showing a relationship between the photoconductor and the charging roller in FIG. 5. 1 is a schematic cross-sectional view showing a schematic configuration of a tandem type image forming apparatus according to the present invention. It is a schematic sectional drawing which shows the process cartridge which concerns on one Embodiment by this invention. It is a table | surface figure which shows the evaluation result about the photoreceptor of each Example and comparative example by this invention.

Explanation of symbols

1, 1K, 1Y, 1M, 1C Photoconductor 2, 2K, 2Y, 2M, 2C Charge roller L, LK, LY, LM, LC Exposure 4, 4K, 4Y, 4M, 4C Developing device 5, 5K, 5Y, 5M 5C Cleaning device 10 Transfer belt 12 Fixing device 15, 61 Aluminum support 16 Alumite layer 16a Barrier layer 16b Porous layer 16c Hole 16d Cell 17 Charge generation layer 18 Charge transport layer 62 Pressure vessel 63 Lid 64 Drum support stand 65 Dispersion tank 66 Stirrer 67 Tank 68, 71 Valve 69, 72 Pump 70, 74 Three-way valve 73 Heater 75 Supercritical fluid in which sealing agent is dispersed

Claims (7)

A method for producing an electrophotographic photoreceptor, comprising forming an anodic oxide film having a thickness of 2 μm to 10 μm on an aluminum support, performing a sealing treatment on the anodic oxide film, and then forming a photosensitive layer on the anodic oxide film In
In the sealing treatment, after an anodic oxide film is formed on the aluminum support, the anodic oxide film is immersed in at least one of a supercritical fluid and a subcritical fluid containing a sealing agent. A method for producing an electrophotographic photoreceptor, comprising sealing pores in the anodized film in a temperature range of 90 ° C. In the manufacturing method of the electrophotographic photosensitive member according to claim 1,
The method for producing an electrophotographic photoreceptor, wherein the sealing agent is a nickel compound. In the manufacturing method of the electrophotographic photosensitive member according to claim 1 or 2,
The method for producing an electrophotographic photoreceptor, wherein the supercritical fluid or subcritical fluid is carbon dioxide. In an electrophotographic photoreceptor having a photosensitive layer formed on an anodized film on an aluminum support,
The electrophotographic photosensitive member produced by the method for producing an electrophotographic photosensitive member according to any one of claims 1 to 3. An image forming apparatus comprising: an electrophotographic photosensitive member that forms an electrostatic latent image on a surface; and a developing device that supplies toner to the electrostatic latent image to convert the electrostatic latent image into a toner image.
The image forming apparatus according to claim 4, wherein the electrophotographic photoreceptor is the electrophotographic photoreceptor according to claim 4. The image forming apparatus according to claim 5.
The image forming apparatus includes a plurality of developing devices and a plurality of electrophotographic photosensitive members that are paired with the developing devices, and each of the developing devices accommodates a different color toner and corresponds to each toner. To the electrophotographic photosensitive member to form toner images of different colors on the surfaces of the respective electrophotographic photosensitive members, and the developing device and the electrophotographic photosensitive member forming a pair transfer the transfer member onto which the toner image is transferred. An image forming apparatus arranged along a direction. In a process cartridge in which an electrophotographic photosensitive member is integrated with at least one of a developing device, a cleaning device, and a charging device,
The process cartridge according to claim 4, wherein the electrophotographic photosensitive member is an electrophotographic photosensitive member according to claim 4.

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