JP2017090609A - Electrophotographic photoreceptor and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor that can provide high wear resistance, and excellent dot reproducibility and potential stability, and a manufacturing method of the same.SOLUTION: The present manufacturing method of an electrophotographic photoreceptor is a method of manufacturing an electrophotographic photoreceptor having a charge generating layer, a charge transport layer, and a protective layer laminated in this order on a conductive substrate, where the protective layer contains metal oxide fine particles in a resin and uses, as the metal oxide fine particles, ones subjected to processing of being stirred in liquid nitrogen together with a medium. In the manufacturing method of an electrophotographic photoreceptor, it is preferable that the metal oxide fine particles be p-type semiconductor fine particles.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrophotographic photosensitive member used in an electrophotographic image forming process and a method for manufacturing the same.

An electrophotographic photosensitive member (hereinafter also simply referred to as “photosensitive member”) that constitutes an image forming apparatus such as an electrophotographic copying machine or a printer has a long life and the image quality stability of the formed image. Is required. In the photoconductor, the lifetime of the photoconductor is determined as the surface of the photoconductor is worn.
In recent years, as a photoreceptor that has excellent wear resistance, scratch resistance and environmental stability and has a long life, a photosensitive layer is laminated on a conductive support, and a protective layer made of a cured resin is formed on the photosensitive layer. Photoconductors have been developed.

  In such a photoreceptor, in order to improve wear resistance, potential stability, etc., for example, it has been proposed that the protective layer further contains P-type semiconductor fine particles as high-strength fine particles having hole transportability (for example, , See Patent Document 1).

  However, the actual situation is that the demands for further wear resistance and potential stability are not sufficiently met.

Japanese Patent Laying-Open No. 2015-141269

  The present invention has been made based on the above circumstances, and an object thereof is an electrophotographic photosensitive member capable of obtaining high wear resistance, excellent dot reproducibility and potential stability, and a method for producing the same. Is to provide.

The method for producing an electrophotographic photoreceptor of the present invention is a method for producing an electrophotographic photoreceptor in which a charge generation layer, a charge transport layer and a protective layer are laminated in this order on a conductive support,
The protective layer contains metal oxide fine particles in the resin,
As the metal oxide fine particles, those finely treated with a medium in liquid nitrogen are used.

  In the method for producing an electrophotographic photoreceptor of the present invention, the metal oxide fine particles are preferably P-type semiconductor fine particles.

In the method for producing an electrophotographic photosensitive member according to the present invention, the P-type semiconductor fine particles are preferably CuAlO ₂ fine particles.

The electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member in which a charge generation layer, a charge transport layer and a protective layer are laminated in this order on a conductive support,
The protective layer contains metal oxide fine particles in the resin,
The protective layer contains metal oxide fine particles in the resin,
The metal oxide fine particles have been subjected to a treatment for stirring together with a medium in liquid nitrogen.

  According to the method for producing an electrophotographic photosensitive member of the present invention, having a protective layer containing metal oxide fine particles that have been treated with a medium in liquid nitrogen, has high wear resistance, and is excellent. Dot reproducibility and potential stability are obtained.

FIG. 3 is a partial cross-sectional view illustrating an example of a layer configuration of the electrophotographic photoreceptor of the present invention. 1 is a cross-sectional view illustrating the configuration of an example of an image forming apparatus on which an electrophotographic photosensitive member of the present invention is mounted.

  Hereinafter, the present invention will be specifically described.

[Photoreceptor]
The photoconductor of the present invention is a photoconductor mounted on an image forming apparatus including a charging unit, an exposure unit, a developing unit, a transfer unit, and a cleaning unit, and a photosensitive layer and a protective layer are arranged in this order on a conductive support. It is an organic photoreceptor formed by lamination.

  In the present invention, the organic photoreceptor means a structure in which at least one of a charge generation function and a charge transport function essential to the structure of the photoreceptor is exhibited by an organic compound. Or a photosensitive member having an organic photosensitive layer composed of an organic charge transport material, a photosensitive member having all known organic photoreceptors, such as a photosensitive member having an organic photosensitive layer in which a charge generation function and a charge transport function are composed of a polymer complex. Say.

  For example, as shown in FIG. 1, the photoconductor 1 is formed by laminating an intermediate layer 1b, a charge generation layer 1c, a charge transport layer 1d, and a protective layer 1e in this order on a conductive support 1a. The photosensitive layer 1f is composed of the charge generation layer 1c and the charge transport layer 1d.

[Protective layer 1e]
The protective layer constituting the photoreceptor of the present invention is also referred to as a treatment (hereinafter referred to as “medium agitation treatment”) in a binder resin (hereinafter, also referred to as “binder resin for protective layer”) and a medium in liquid nitrogen. ) Containing metal oxide fine particles 1eA.

[Metal oxide fine particle medium stirring treatment]
Specifically, the medium agitation treatment is a so-called refinement of the raw metal oxide fine particles by stirring a slurry (suspension of solid particles) containing liquid nitrogen and raw metal oxide fine particles together with, for example, a dispersion medium. It is a pulverization process by a medium pulverization method.
After the medium stirring treatment, liquid nitrogen is removed from the obtained metal oxide fine particles to form powder.
Liquid nitrogen can be removed (volatilized) by natural drying.

  The slurry is preferably mixed at a ratio of 50 to 5000 parts by mass of liquid nitrogen as a dispersion medium with respect to 100 parts by mass of the raw material metal oxide fine particles.

Moreover, as a device used for stirring the slurry, for example, a wet media dispersion type device can be used.
The wet media dispersion type device is filled with beads as a medium in a container, and further agitated blades mounted perpendicular to the rotation axis are rotated at high speed to crush and disperse the aggregated particles of metal oxide fine particles. An apparatus having a process, for example, various types such as a vertical type, a horizontal type, a continuous type, and a batch type can be used. Specifically, a bead mill, a sand mill, an ultra visco mill, a pearl mill, a glen mill, a dyno mill, an agitator mill, a dynamic mill, and the like can be used. These dispersion-type devices are pulverized and dispersed by impact crushing, friction, shearing, shear stress, etc. using a grinding medium (media) such as balls and beads.

The stirring speed of the slurry can be set to, for example, 500 to 2000 rpm.
Moreover, stirring time can be 0.5 to 10 hours, for example.
The longer the stirring time, the smaller the particle size of the metal oxide fine particles subjected to the medium stirring treatment to be obtained. Specifically, for example, when the stirring time is 1 hour, the particle size is about 100 nm. In the case of 3 hours, fine particles having a particle size of about 50 nm can be obtained, and in the case of 5 hours, fine particles having a particle size of about 30 nm can be obtained.

As the dispersion medium, for example, zirconia beads, glass beads, alumina beads, and dry ice beads can be used, and it is particularly preferable to use zirconia beads or dry ice beads.
Further, it is preferable to use a bead having a diameter of about 0.1 to 1.0 mm.

[Raw metal oxide fine particles]
The raw material metal oxide fine particles are preferably conductive, and examples of such metal oxide fine particles include N-type semiconductor fine particles and P-type semiconductor fine particles, and P-type semiconductor fine particles are used. Is particularly preferred.

P-type semiconductor fine particles are semiconductor particles in which carriers for transporting electric charges are holes, and contribute to image quality stability.
Examples of the P-type semiconductor fine particles include fine particles such as Cu ₂ O, CuAlO ₂ , and SrCu ₂ O _2, and it is particularly preferable to use CuAlO ₂ fine particles.

The P-type semiconductor fine particles are preferably produced by, for example, a sintering method (solid phase method). Specifically, when using PAl type semiconductor particles made of CuAlO ₂ , Al ₂ O ₃ (purity 99.9%) and Cu ₂ O (99.9%) are mixed at a molar ratio of 1: 1. After calcining for 4 days at a temperature of 1100 ° C. in an Ar atmosphere, the pellets are molded and sintered at 1100 ° C. for 2 days to obtain a sintered body. Then, after coarsely pulverizing to several hundred μm, CuAlO ₂ having a desired particle diameter can be obtained by finely pulverizing the obtained coarse particles and solvent using a wet media dispersion type apparatus.

N-type semiconductor particles use electrons as carriers for transporting electric charges.
Examples of the N-type semiconductor fine particles include SnO ₂ , ZnO, and TiO ₂ , and SnO ₂ is preferably used from the viewpoint of the hardness, conductivity, and light transmittance of the protective layer obtained.

  As the N-type semiconductor fine particles, those produced by a general method such as a gas phase method, a chlorine method, a sulfuric acid method, a plasma method, or an electrolytic method can be used.

[Surface treatment of metal oxide fine particles]
In the medium stirring treatment of metal oxide fine particles, a surface treatment agent such as a silane coupling agent is stirred together from the viewpoint of further improving the dispersibility of the metal oxide fine particles in the protective layer and further improving the wear resistance. The metal oxide fine particles may be subjected to a surface treatment. Examples of the surface treatment agent include a silane coupling agent and a titanium coupling agent. In particular, for the purpose of further increasing the hardness of the protective layer, it is preferable to use a silane coupling agent having a radical polymerizable reactive group.
By using a silane coupling agent having a radical polymerizable reactive group, when the protective layer binder resin is a cured resin by a polymerizable compound described later, a strong protective layer is formed to react with the polymerizable compound. be able to.
As the silane coupling agent having a radical polymerizable reactive group, it is preferable to use a silane coupling agent having an acryloyl group or a methacryloyl group. Examples of the silane coupling agent having such a radical polymerizable reactive group include the following. Examples of known compounds are as follows.

_{S-1: CH 2 = CHSi} (CH 3) (OCH 3) 2
_{S-2: CH 2 = CHSi} (OCH 3) 3
S-3: CH ₂ = CHSiCl _{3
S-4: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-5: CH 2 = CHCOO} (CH 2) 2 Si (OCH 3) 3
_{S-6: CH 2 = CHCOO} (CH 2) 2 Si (OC 2 H 5) (OCH 3) 2
_{S-7: CH 2 = CHCOO} (CH 2) 3 Si (OCH 3) 3
_{S-8: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) Cl 2
_{S-9: CH 2 = CHCOO} (CH 2) 2 SiCl 3
_{S-10: CH 2 = CHCOO} (CH 2) 3 Si (CH 3) Cl 2
S-11: CH ₂ = CHCOO (CH ₂ ) ₃ SiCl _{3
S-12: CH 2 = C} (CH 3) COO (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-13: CH 2 = C} (CH 3) COO (CH 2) 2 Si (OCH 3) 3
_{S-14: CH 2 = C} (CH 3) COO (CH 2) 3 Si (CH 3) (OCH 3) 2
_{S-15: CH 2 = C} (CH 3) COO (CH 2) 3 Si (OCH 3) 3
_{S-16: CH 2 = C} (CH 3) COO (CH 2) 2 Si (CH 3) Cl 2
_{S-17: CH 2 = C} (CH 3) COO (CH 2) 2 SiCl 3
_{S-18: CH 2 = C} (CH 3) COO (CH 2) 3 Si (CH 3) Cl 2
_{S-19: CH 2 = C} (CH 3) COO (CH 2) 3 SiCl 3
_{S-20: CH 2 = CHSi} (C 2 H 5) (OCH 3) 2
_{S-21: CH 2 = C} (CH 3) Si (OCH 3) 3
_{S-22: CH 2 = C} (CH 3) Si (OC 2 H 5) 3
_{S-23: CH 2 = CHSi} (OCH 3) 3
_{S-24: CH 2 = C} (CH 3) Si (CH 3) (OCH 3) 2
_{S-25: CH 2 = CHSi} (CH 3) Cl 2
_{S-26: CH 2 = CHCOOSi} (OCH 3) 3
_{S-27: CH 2 = CHCOOSi} (OC 2 H 5) 3
_{S-28: CH 2 = C} (CH 3) COOSi (OCH 3) 3
_{S-29: CH 2 = C} (CH 3) COOSi (OC 2 H 5) 3
_{S-30: CH 2 = C} (CH 3) COO (CH 2) 3 Si (OC 2 H 5) 3
_{S-31: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) 2 (OCH 3)
_{S-32: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OCOCH 3) 2
_{S-33: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (ONHCH 3) 2
_{S-34: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OC 6 H 5) 2
_{S-35: CH 2 = CHCOO} (CH 2) 2 Si (C 10 H 21) (OCH 3) 2
_{S-36: CH 2 = CHCOO} (CH 2) 2 Si (CH 2 C 6 H 5) (OCH 3) 2

  As the surface treatment agent, in addition to S-1 to S-36, a silane compound having a reactive organic group capable of performing a radical polymerization reaction can be used. These surface treatment agents can be used alone or in admixture of two or more.

  Moreover, the usage-amount of a surface treating agent is although it does not restrict | limit in particular, It is preferable that it is 0.1-100 mass parts with respect to 100 mass parts of raw material metal oxide fine particles.

The number average primary particle size of the metal oxide fine particles subjected to the medium stirring treatment is preferably 10 to 70 nm, and more preferably 30 to 50 nm.
When the number average primary particle size of the metal oxide fine particles subjected to the medium stirring treatment is less than 10 nm, the dispersibility in the coating liquid for forming the protective layer is lowered, so that the metal oxidation subjected to the medium stirring treatment is performed. Fine particles may agglomerate, and thus a uniform coating film may not be formed. On the other hand, when the number average primary particle size of the metal oxide fine particles subjected to the medium stirring treatment exceeds 70 nm, the strength of the protective layer may be reduced.

  The number average primary particle size of the metal oxide fine particles subjected to the medium stirring treatment was taken with a scanning electron microscope “JSM-7500F” (manufactured by JEOL Ltd.) at a magnification of 100,000 times, and the photograph was captured by a scanner. For the photographic image (excluding the agglomerated particles), an automatic image processing analyzer “LUZEX (registered trademark) AP (software version Ver. 1.32)” (manufactured by Nireco Corporation) The valuation treatment is performed, the horizontal ferret diameter for any 100 metal oxide fine particles is calculated, and the average value is taken as the number average primary particle diameter. Here, the horizontal ferret diameter refers to the length of a side parallel to the x-axis of the circumscribed rectangle when the image of the metal oxide fine particles is binarized.

The metal oxide fine particles subjected to the medium stirring treatment are preferably contained in a proportion of 20 to 300 parts by mass, more preferably 50 to 200 parts by mass with respect to 100 parts by mass of the protective layer binder resin.
When the content ratio of the metal oxide fine particles subjected to the medium stirring treatment is in the above range, an appropriate charge transport property can be obtained in the protective layer and the hardness of the protective layer can be appropriately adjusted.

According to the photoreceptor as described above, high abrasion resistance, and excellent dot reproducibility and potential stability can be obtained by having the protective layer containing the metal oxide fine particles subjected to the medium stirring treatment. .
The reason why high abrasion resistance and excellent dot reproducibility and potential stability can be obtained in a photoreceptor having such a protective layer is presumed as follows.
That is, the metal oxide fine particles produced by a sintering method (solid phase method) at a high temperature are usually coarse particles having a particle size of several μm. When the coarse powder particles are subjected to a medium stirring treatment in a liquefied inert gas (liquid nitrogen), heat is not generated due to collision with the dispersion media (beads) because it is performed at an ultra-low temperature, and deterioration due to heat does not occur. , Since the dispersion medium is a liquefied inert gas, it is possible to suppress the generation of impurities without adhering to the surface of the coarse particles, and thus, metal oxide fine particles having high uniformity in shape and particle size can be obtained. It is done. In addition, since the liquefied inert gas evaporates at a temperature below room temperature, it is necessary to give heat energy for drying to the metal oxide fine particles when recovering the metal oxide fine particles obtained after the medium stirring treatment. Therefore, it is possible to suppress deterioration of the electrical characteristics of the metal oxide fine particles and aggregation of the metal oxide fine particles. Furthermore, even when the particle size is reduced, the metal oxide fine particles can be prevented from aggregating due to heat or the like. For these reasons, the metal oxide fine particles subjected to the medium stirring treatment can be dispersed with high dispersibility in the protective layer of the photoreceptor, and as a result, high wear resistance and excellent dot reproducibility can be obtained. And excellent potential stability is obtained.
In addition, when the coarse particles of metal oxide fine particles produced by the sintering method (solid phase method) are subjected to a medium stirring treatment using, for example, an alcohol solvent or an alkoxy solvent as a dispersion medium, It is difficult to increase the uniformity of the shape and particle size of the metal oxide fine particles because the dispersion medium adheres to the surface and impurities are generated.

[Binder resin for protective layer]
The binder resin for the protective layer is preferably a thermoplastic resin or a photocurable resin, and more preferably a photocurable resin because a high film strength can be obtained.
As the protective layer binder resin, for example, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, acrylic resin, melamine resin and the like can be used. When a thermoplastic resin is used, it is preferably a polycarbonate resin. When a photocurable resin is used, a crosslinkable polymerizable compound, specifically a compound having two or more radical polymerizable functional groups (hereinafter also referred to as “polyfunctional radical polymerizable compound”). It is preferably a cured resin obtained by a polymerization reaction by irradiation with active rays such as ultraviolet rays and electron beams.
The above-mentioned materials mentioned as the protective layer binder resin can be used alone or in combination of two or more.

[Polyfunctional radical polymerizable compound]
Since the polyfunctional radical polymerizable compound can be cured in a small amount of light or in a short time, an acryloyl group (CH ₂ ═CHCO—) or a methacryloyl group (CH ₂ ═CCH ₃ CO—) is used as the radical polymerizable functional group. ) Is particularly preferably an acrylic monomer having two or more) or oligomers thereof. Accordingly, the curable resin is preferably an acrylic resin formed from an acrylic monomer or an oligomer thereof.

  Examples of these polyfunctional radically polymerizable compounds include the following compounds.

However, in the chemical formulas showing the exemplary compounds M1 to M15, R represents an acryloyl group (CH ₂ ═CHCO—), and R ′ represents a methacryloyl group (CH ₂ ═CCH ₃ CO—).

  The protective layer may contain lubricant particles, various antioxidants, and the like, if necessary, in addition to the protective layer binder resin and the metal oxide fine particles subjected to the medium stirring treatment as described above.

[Lubricant particles]
Examples of the lubricant particles include fluorine atom-containing resin particles. Examples of the fluorine atom-containing resin particles include ethylene tetrafluoride resin, ethylene trifluoride chloride resin, hexafluoroethylene chloride propylene resin, vinyl fluoride resin, vinylidene fluoride resin, and ethylene difluoride dichloride resin. These copolymers can also be used. These can be used individually by 1 type or in combination of 2 or more types. Among these, it is particularly preferable to use a tetrafluoroethylene resin and a vinylidene fluoride resin.

  The thickness of the protective layer is preferably 0.2 to 10 μm, more preferably 0.5 to 6 μm.

(Formation of protective layer)
The protective layer is a coating prepared by adding a polyfunctional radical polymerizable compound, metal oxide fine particles subjected to a medium stirring treatment and, if necessary, known resins, polymerization initiators, lubricant particles, antioxidants and the like to a solvent. The solution can be prepared by applying the solution to the surface of the charge transport layer by a known method to form a coating film and curing.

(Polymerization initiator)
As a method for polymerizing the polyfunctional radically polymerizable compound, a method using an electron beam cleavage reaction or a method using light or heat in the presence of a radical polymerization initiator can be employed.
Examples of the radical polymerization initiator that initiates the polymerization reaction of the polyfunctional radically polymerizable compound include a thermal polymerization initiator and a photopolymerization initiator, and these can be used in combination.

  As thermal polymerization initiators, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylazobisvaleronyl), 2,2′-azobis (2-methylbutyro) Azo compounds such as nitrile); peroxides such as benzoyl peroxide (BPO), di-tert-butyl hydroperoxide, tert-butyl hydroperoxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, lauroyl peroxide An oxide etc. are mentioned.

  Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 (“Irgacure 369” (manufactured by BASF Japan)), 2-hydroxy-2- Methyl-1-phenylpropan-1-one, 2-methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime Acetophenone or ketal photoinitiators such as benzoin, benzoin methyl ether, Benzoin ether photopolymerization initiators such as benzoin ethyl ether, benzoin isobutyl ether, benzoin isopropyl ether; benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoyl Benzophenone photopolymerization initiators such as phenyl ether, acrylated benzophenone, 1,4-benzoylbenzene; 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4- Examples thereof include thioxanthone photopolymerization initiators such as dichlorothioxanthone.

  Other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine Oxide (“Irgacure 819” (manufactured by BASF Japan)), bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10-phenanthrene, acridine series Examples thereof include compounds, triazine compounds, and imidazole compounds. Moreover, what has a photopolymerization promotion effect can be used individually or in combination with the said photoinitiator. Examples of the photopolymerization promoting effect include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4′- Examples include dimethylaminobenzophenone.

  The polymerization initiator is preferably a photopolymerization initiator, more preferably an alkylphenone compound or a phosphine oxide compound, and a photopolymerization initiator having an α-hydroxyacetophenone structure or an acylphosphine oxide structure. More preferably, an agent is used.

These polymerization initiators may be used alone or in combination of two or more.
The usage-amount of a polymerization initiator is 0.1-40 mass parts with respect to 100 mass parts of polyfunctional radically polymerizable compounds, Preferably it is 0.5-20 mass parts.

〔solvent〕
Solvents used for forming the protective layer include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-2-propanol, benzyl alcohol, methyl isopropyl ketone, and methyl isobutyl ketone. , Methyl ethyl ketone, cyclohexane, toluene, xylene, methylene chloride, ethyl acetate, butyl acetate, 2-methoxyethanol, 2-ethoxyethanol, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine and diethylamine. It is not limited to.
These can be used individually by 1 type or in mixture of 2 or more types.

  In the curing process, the coating film is irradiated with actinic rays to generate radicals, polymerize, and form a cross-linking bond by a cross-linking reaction between molecules and within the molecule to form a binder resin for the protective layer. Is preferred. As an actinic ray, it is preferable to use light such as ultraviolet light and visible light and an electron beam, and it is particularly preferable to use ultraviolet light from the viewpoint of ease of use.

As the ultraviolet light source, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a flash (pulse) xenon, an ultraviolet LED, or the like can be used. Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually 1 to 20 mJ / cm ² , preferably 5 to 15 mJ / cm ² . The output voltage of the light source is preferably 0.1 to 5 kW, and particularly preferably 0.5 to 3 kW.

  As the electron beam source, for example, a curtain beam type electron beam irradiation apparatus can be preferably used. The acceleration voltage at the time of irradiation with an electron beam is preferably 100 to 300 kV. The absorbed dose is preferably 0.005 Gy to 100 kGy (0.5 to 10 Mrad).

  The irradiation time of the actinic radiation may be a time for obtaining the necessary irradiation amount of the actinic radiation, specifically 0.1 seconds to 10 minutes is preferable, and 1 second to 5 minutes is preferable from the viewpoint of curing efficiency or work efficiency. More preferred.

  The coating film may be dried before and after irradiation with active rays and during irradiation with active rays. The timing for performing the drying process can be appropriately selected in combination with the irradiation condition of the active rays. The drying conditions for the protective layer can be appropriately selected depending on the type of solvent used in the coating solution, the thickness of the protective layer, and the like. The drying temperature is preferably room temperature to 180 ° C, particularly preferably 80 to 140 ° C. The drying time is preferably 1 to 200 minutes, particularly preferably 5 to 100 minutes. By drying the coating film under such drying conditions, the amount of solvent contained in the protective layer can be controlled in the range of 20 ppm to 75 ppm.

  Hereinafter, the configuration of the photoreceptor other than the protective layer will be described.

[Conductive support 1a]
The conductive support only needs to have conductivity, for example, a metal such as aluminum, copper, chromium, nickel, zinc and stainless steel formed into a drum or a sheet, or a metal foil such as aluminum or copper. Examples include those laminated on plastic films, aluminum, indium oxide, tin oxide, etc. deposited on plastic films, metals with conductive layers applied alone or with a binder resin, plastic films and paper .

[Intermediate layer 1b]
The intermediate layer provides a barrier function and an adhesive function between the conductive support and the organic photosensitive layer. From the viewpoint of preventing various failures, it is preferable to provide such an intermediate layer.

  Such an intermediate layer contains, for example, a binder resin (hereinafter also referred to as “binder resin for intermediate layer”) and, if necessary, conductive particles and metal oxide particles.

  Examples of the intermediate layer binder resin include casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide resin, polyurethane resin, and gelatin. Among these, alcohol-soluble polyamide resins are preferable.

The intermediate layer can contain various conductive particles and metal oxide particles for the purpose of adjusting the resistance. For example, various metal oxide particles such as alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, and bismuth oxide can be used. Ultrafine particles such as indium oxide doped with tin, tin oxide doped with antimony, and zirconium oxide can be used.
The number average primary particle size of such metal oxide particles is preferably 0.3 μm or less, and more preferably 0.1 μm or less.
You may use a metal oxide particle individually by 1 type or in mixture of 2 or more types. When two or more kinds are mixed, it may take the form of a solid solution or fusion.

  It is preferable that the content rate of electroconductive particle or metal oxide particle is 20-400 mass parts with respect to 100 mass parts of binder resin for intermediate | middle layers, More preferably, it is 50-200 mass parts.

The above intermediate layer is prepared by, for example, dissolving an intermediate layer binder resin in a known solvent, and dispersing conductive particles or metal oxide particles as necessary to prepare a coating solution for forming an intermediate layer. The intermediate layer-forming coating solution can be applied to the surface of the conductive support to form a coating film, and the coating film can be dried.
The concentration of the intermediate layer binder resin in the intermediate layer forming coating solution can be appropriately selected according to the thickness of the intermediate layer and the coating method.

  The solvent used for the formation of the intermediate layer is not particularly limited, and various known organic solvents can be used, but good solubility and coating performance with respect to the polyamide resin which is preferable as the binder resin for the intermediate layer Therefore, it is preferable to use alcohols having 2 to 4 carbon atoms such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol and sec-butanol. Moreover, in order to improve preservability and the dispersibility of electroconductive particle or metal oxide particle, a cosolvent can be used together with the said solvent. Preferred examples of the cosolvent include methanol, benzyl alcohol, toluene, cyclohexanone, tetrahydrofuran and the like. These solvents and cosolvents can be used alone or in combination of two or more.

  As a means for dispersing the conductive particles and metal oxide particles, an ultrasonic disperser, a ball mill, a sand grinder, a homomixer, or the like can be used.

  The coating method for the intermediate layer forming coating solution is not particularly limited. For example, dip coating method, spray coating method, spinner coating method, bead coating method, blade coating method, beam coating method, circular amount regulation type coating method ( A circular slide hopper coating method).

  As a method for drying the coating film, a known drying method can be appropriately selected according to the type of solvent and the film thickness of the intermediate layer to be formed, and thermal drying is particularly preferable.

  The thickness of the intermediate layer is preferably 0.1 to 15 μm, and more preferably 0.3 to 10 μm.

[Charge generation layer 1c]
The charge generation layer contains a charge generation material and a binder resin (hereinafter also referred to as “binder resin for charge generation layer”).

  Examples of charge generation materials include azo raw materials such as Sudan Red and Diane Blue, quinone pigments such as pyrenequinone and anthanthrone, quinocyanine pigments, perylene pigments, indigo pigments such as indigo and thioindigo, pyranthrone and diphthaloylpyrene. Examples thereof include, but are not limited to, ring quinone pigments and phthalocyanine pigments. Among these, polycyclic quinone pigments and titanyl phthalocyanine pigments are preferable. These charge generation materials may be used alone or in combination of two or more.

  As the binder resin for the charge generation layer, known resins can be used. For example, polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, Polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and copolymer resin containing two or more of these resins (for example, vinyl chloride-vinyl acetate copolymer resin, chloride) Vinyl-vinyl acetate-maleic anhydride copolymer resin), poly-vinylcarbazole resin, and the like, but are not limited thereto. Among these, polyvinyl butyral resin is preferable.

  The mixing ratio of the charge generation layer binder resin and the charge generation material is preferably 1 to 600 parts by mass, more preferably 50 to 500 parts by mass, relative to 100 parts by mass of the charge generation layer binder resin. Part by mass. When the mixing ratio of the charge generating layer binder resin and the charge generating material is in the above range, high dispersion stability is obtained in the coating solution for forming the charge generating layer, which will be described later. The resistance is suppressed to be low, and an increase in residual potential due to repeated use can be extremely suppressed.

  The charge generation layer as described above is prepared by, for example, preparing a charge generation layer forming coating solution by adding and dispersing a charge generation material in a charge generation layer binder resin dissolved in a known solvent. It can be formed by applying a coating liquid for layer formation onto the surface of the intermediate layer to form a coating film and drying the coating film.

  As the solvent used for forming the charge generation layer, a solvent capable of dissolving the charge generation layer binder resin may be used. For example, ketone solvents such as methyl ethyl ketone and cyclohexanone, tetrahydrofuran, 1-dioxane, 1, 3 -Ether solvents such as dioxolane, alcohol solvents such as methyl cellsolve, ethyl cellsolve, methanol, ethanol, propanol and butanol, ester solvents such as ethyl acetate and t-butyl acetate, aromatic solvents such as toluene and xylene However, it is not limited to these. These may be used alone or in combination of two or more.

Examples of the means for dispersing the charge generating substance include the same method as the means for dispersing the conductive particles and metal oxide particles in the coating liquid for forming the intermediate layer.
Examples of the coating method for the charge generation layer forming coating solution include the same methods as those mentioned as the coating method for the intermediate layer forming coating solution.

  The thickness of the charge generation layer is preferably 0.01 to 5 μm, more preferably 0.05 to 3 μm, although it varies depending on the characteristics of the charge generation material, the characteristics and the content ratio of the binder resin for charge generation layer.

[Charge transport layer 1d]
The charge transport layer contains a charge transport material and a binder resin (hereinafter also referred to as “binder resin for charge transport layer”).

  As a charge transport material for the charge transport layer, for example, carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bis Imidazolidine derivatives, styryl compounds, hydrazone compounds, pyrazoline compounds, oxazolone derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, benzidine derivatives , Poly-N-vinylcarbazole, poly-1-vinylpyrene and poly-9-vinylanthracene.These may be used alone or in combination of two or more.

  A known resin can be used as the binder resin for the charge transport layer. Polycarbonate resin, polyacrylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polymethacrylic ester resin, styrene-methacrylic ester Examples of the resin include a copolymer resin, and a polycarbonate resin is preferable. Furthermore, BPA (bisphenol A) type, BPZ (bisphenol Z) type, dimethyl BPA type, BPA-dimethyl BPA copolymer type polycarbonate resin and the like are preferable in terms of crack resistance, wear resistance, and charging characteristics.

  The content ratio of the charge transport material in the charge transport layer is preferably 10 to 500 parts by weight, more preferably 20 to 100 parts by weight with respect to 100 parts by weight of the charge transport layer binder resin.

  In the charge transport layer, an antioxidant, an electronic conductive agent, a stabilizer, silicone oil, or the like may be added. As the antioxidant, those disclosed in JP-A No. 2000-305291 and as the electronic conductive agent are disclosed in JP-A Nos. 50-137543 and 58-76483.

  The layer thickness of the charge transport layer varies depending on the characteristics of the charge transport material, the characteristics and the content ratio of the binder resin for the charge transport layer, but is preferably 5 to 40 μm, more preferably 10 to 30 μm.

The charge transport layer as described above is prepared, for example, by adding and dispersing a charge transport material (CTM) in a binder resin for a charge transport layer dissolved in a known solvent to prepare a coating solution for forming a charge transport layer. The charge transport layer forming coating solution can be applied to the surface of the charge generation layer to form a coating film, and the coating film can be dried.
Examples of the solvent used for forming the charge transport layer include the same solvents as those used for forming the charge generation layer.
In addition, as the method for applying the charge transport layer forming coating solution, the same method as the method for applying the charge generating layer forming coating solution can be used.

[Image forming apparatus]
The photoconductor of the present invention includes, for example, a charging unit that charges the surface of the photoconductor, an exposure unit that exposes the photoconductor charged by the charging unit to form an electrostatic latent image, and a toner on the photoconductor. A developing means for supplying and developing the electrostatic latent image with toner to form a toner image; a transfer means for transferring the toner image formed on the photoreceptor; and a cleaning for removing the toner remaining on the surface of the photoreceptor. And an image forming apparatus.

FIG. 2 is a cross-sectional view illustrating the configuration of an example of the image forming apparatus according to the present invention.
This image forming apparatus is called a tandem type color image forming apparatus, and includes four sets of image forming units (image forming units) 10Y, 10M, 10C, and 10Bk, an intermediate transfer body unit 70, a paper feeding unit 21, and And fixing means 24. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

The four sets of image forming units 10Y, 10M, 10C, and 10Bk are centered around the photoreceptors 1Y, 1M, 1C, and 1Bk, charging means 2Y, 2M, 2C, and 2Bk, and exposure means 3Y, 3M, 3C, and 3Bk, Rotating developing means 4Y, 4M, 4C, 4Bk, primary transfer rollers 5Y, 5M, 5C, 5Bk as primary transfer means, and cleaning means 6Y, 6M, 6C, cleaning the photoreceptors 1Y, 1M, 1C, 1Bk It is composed of 6Bk.
The image forming apparatus according to the present invention uses the above-described photoreceptors of the present invention as the photoreceptors 1Y, 1M, 1C, and 1Bk.

  The image forming units 10Y, 10M, 10C, and 10Bk have the same configuration except that the colors of the toner images formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are different from yellow, magenta, cyan, and black, respectively. The forming unit 10Y will be described in detail as an example.

  The image forming unit 10Y includes a charging unit 2Y, an exposing unit 3Y, a developing unit 4Y, and a cleaning unit 6Y around a photoconductor 1Y as an image forming body, and a yellow (Y) toner image is formed on the photoconductor 1Y. To form.

  The charging unit 2Y is a unit that uniformly charges the surface of the photoreceptor 1Y to a negative polarity. As the charging unit 2Y, for example, a corona discharge type charger is used.

  The exposure unit 3Y is a unit that performs exposure based on an image signal (yellow) on the photoreceptor 1Y to which a uniform potential is applied by the charging unit 2Y, and forms an electrostatic latent image corresponding to a yellow image. As the exposure means 3Y, a device composed of an LED having light emitting elements arranged in an array in the axial direction of the photoreceptor 1Y and an imaging element, a laser optical system, or the like is used.

  The developing means 4Y includes, for example, a developing sleeve that contains a magnet and rotates while holding the developer, and a voltage applying device that applies a DC and / or AC bias voltage between the photosensitive member and the developing sleeve.

  The cleaning unit 6Y is a unit that removes toner remaining on the surface of the photoreceptor 1Y. The cleaning means 6Y in this example includes a cleaning blade and a brush roller provided on the upstream side of the cleaning blade.

  In the image forming apparatus of FIG. 2, the photosensitive member 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 6Y of the image forming unit 10Y are integrally supported and provided as a process cartridge. It may be configured to be detachable from the main body A of the image forming apparatus via a guide means such as a rail.

  The image forming units 10Y, 10M, 10C, and 10Bk are arranged in tandem in the vertical direction, and an intermediate transfer body unit 70 is arranged on the left side of the photoreceptors 1Y, 1M, 1C, and 1Bk in the drawing. The intermediate transfer body unit 70 is wound around a plurality of rollers 71, 72, 73, and 74, and is supported by a semiconductive endless belt-like intermediate transfer body 77, and a secondary transfer means. It consists of a next transfer roller 5b and a cleaning means 6b.

  The image forming units 10Y, 10M, 10C, and 10Bk and the intermediate transfer body unit 70 are housed in a housing 80. The housing 80 is pulled out from the main body A of the image forming apparatus via support rails 82L and 82R. It is configured to be possible.

  The fixing unit 24 is, for example, a heat roller fixing configured by a heating roller having a heating source therein and a pressure roller provided in pressure contact with the heating roller so as to form a fixing nip portion. One of the methods is mentioned.

  In FIG. 2, the image forming apparatus according to the present invention is shown as a color laser printer, but may be configured as a monochrome laser printer or a copy. In the image forming apparatus according to the present invention, a light source other than a laser, for example, an LED light source can be used as the exposure light source.

In the image forming apparatus as described above, image formation is performed as follows. That is, first, the charging means 2Y, 2M, 2C, and 2Bk are discharged to the surface of the photoreceptors 1Y, 1M, 1C, and 1Bk to be negatively charged (charging process). Next, the exposure means 3Y, 3M, 3C, and 3Bk expose the surfaces of the photoreceptors 1Y, 1M, 1C, and 1Bk based on the image signal to form an electrostatic latent image (exposure process). Next, with the developing means 4Y, 4M, 4C, and 4Bk, toner is applied to the surface of the photoreceptors 1Y, 1M, 1C, and 1Bk and developed to form a toner image (developing process).
Next, the primary transfer rollers 5Y, 5M, 5C, and 5Bk are brought into contact with the rotating intermediate transfer body 77. Thus, the color toner images formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are sequentially transferred onto the rotating intermediate transfer body 77 to form a color toner image (primary transfer process). During the image forming process, the primary transfer roller 5Bk is always in contact with the photoreceptor 1Bk. On the other hand, the other primary transfer rollers 5Y, 5M, and 5C abut against the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

Then, after separating the primary transfer rollers 5Y, 5M, 5C, and 5Bk from the intermediate transfer body 77, the toner remaining on the surfaces of the photoreceptors 1Y, 1M, 1C, and 1Bk is cleaned with the cleaning means 6Y, 6M, 6C, and 6Bk. To remove (cleaning step). Thereafter, in preparation for the next image forming process, the surfaces of the photoreceptors 1Y, 1M, 1C, and 1Bk are neutralized by a neutralizing unit (not shown) as necessary.
As described above, this image forming apparatus is configured such that the lubricant is supplied to the surfaces of the photoreceptors 1Y, 1M, 1C, and 1Bk for each image forming process.

On the other hand, a transfer material P (for example, a support for carrying a final image such as plain paper or a transparent sheet) accommodated in the paper feed cassette 20 is fed by the paper feed means 21 and a plurality of intermediate rollers 22A, 22B, 22C. , 22D, and the registration roller 23, and is conveyed to a secondary transfer roller 5b as a secondary transfer unit. The secondary transfer roller 5b is brought into contact with the intermediate transfer member 77, whereby a color toner image is formed on the transfer material P. Are transferred at once. The transfer material P onto which the color toner image has been transferred is fixed by the fixing means 24, is sandwiched between the paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus. The secondary transfer roller 5b is brought into contact with the intermediate transfer member 77 only when secondary transfer is performed.
After the color toner image is transferred to the transfer material P by the secondary transfer roller 5b, the residual toner is removed by the cleaning means 6b from the intermediate transfer body 77 from which the transfer material P is separated by curvature.

[Toner and developer]
The toner used in the image forming apparatus according to the present invention is not particularly limited, but includes toner particles containing a binder resin and a colorant. The toner particles may include other components such as a release agent as desired. It may be contained.

  As the toner, either a pulverized toner or a polymerized toner can be used. However, in the image forming apparatus according to the present invention, it is preferable to use a polymerized toner from the viewpoint of obtaining a high quality image.

  The average particle diameter of the toner is preferably 2 to 8 μm in terms of volume-based median diameter. By setting this range, the resolution can be increased.

  In addition, an appropriate amount of inorganic fine particles such as silica and titania having an average particle diameter of about 10 to 300 nm and an abrasive of about 0.2 to 3 μm can be externally added to the toner particles as external additives.

The toner can be used as a magnetic or nonmagnetic one-component developer, but may be mixed with a carrier and used as a two-component developer.
In the case where the toner is used as a two-component developer, the carrier may be a conventionally known material such as a ferromagnetic metal such as iron, an alloy such as ferromagnetic metal and aluminum and lead, and a compound of ferromagnetic metal such as ferrite and magnetite. In particular, ferrite is preferable.

  As mentioned above, although embodiment of this invention was described concretely, embodiment of this invention is not limited to said example, A various change can be added.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

[Example 1 of medium stirring treatment for metal oxide fine particles]
Dispersion medium: 100 parts by mass of φ0.5 mm zirconia beads and dispersoid: 100 parts by mass of metal oxide fine particles (CuAlO ₂ ) were sufficiently cooled under 200 parts by mass of liquid nitrogen as a dispersion medium, and this was equipped with a stirring blade After putting into a bead mill and stirring at 2,000 rpm for 3 hours, the zirconia beads and metal oxide fine particles in liquid nitrogen are passed through a sieve having an opening of 0.1 mm to separate only liquid nitrogen and metal oxide fine particles. Thereafter, liquid nitrogen was volatilized by natural drying to obtain a powder of metal oxide fine particles [1] that had been subjected to a medium stirring treatment with a number average primary particle size of 30 nm.

[Example 2 of medium stirring treatment for metal oxide fine particles]
The number average primary particles in the same manner as in Example 1 of the metal oxide fine particle medium stirring treatment, except that the metal oxide fine particles were made of SnO ₂ instead of CuAlO ₂ and the stirring time was 2 hours. A powder of metal oxide fine particles [2] having a diameter of 50 nm and subjected to a medium stirring treatment was obtained.

[Metal oxide fine particle medium stirring treatment example 3]
In the medium agitation processing example 1 of the metal oxide particles, used as an alternative to those made of CuAlO ₂ as the metal oxide fine particles from SrCu ₂ O _2, in the same manner except that the stirring time was 2 hours, the number average A powder of metal oxide fine particles [3] subjected to medium stirring treatment with a primary particle size of 50 nm was obtained.

[Example 4 of medium stirring treatment for metal oxide fine particles]
In Example 1 of the metal oxide fine particle medium agitation treatment, the number average primary particle size is the same except that CO ₂ (dry ice) beads are used as the dispersion medium instead of zirconia beads and the agitation time is 6 hours. A powder of metal oxide fine particles [4] subjected to a medium stirring treatment of 50 nm was obtained.

[Example 5 of medium stirring for metal oxide fine particles]
In Example 1 of stirring medium for metal oxide fine particles, ethanol was used instead of liquid nitrogen as a dispersion medium, the stirring time was set to 2 hours, and heat drying was performed to evaporate ethanol after separation. A powder of metal oxide fine particles [5] having a number average primary particle size of 100 nm was obtained.

[Example 6 of medium stirring treatment for metal oxide fine particles]
Metal oxide fine particles having a number average primary particle size of 100 nm in the same manner as in Example 5 of stirring the metal oxide fine particles except that water was used instead of ethanol as the dispersion medium and the stirring time was 1 hour. A powder of [6] was obtained.

[Photosensitive body preparation example 1]
(1) Production of conductive support A conductive support [1] of a drum-shaped aluminum support (outer diameter 60 mm) was prepared.

(2) Formation of Intermediate Layer Binder resin for intermediate layer: 100 parts by mass of polyamide resin is added to 1700 parts by mass of a mixed solvent of ethanol / n-propyl alcohol / tetrahydrofuran (volume ratio 45/20/35), and at 20 ° C. Stir and mix. To this solution, 160 parts by mass of titanium oxide particles “SMT500SAS” (manufactured by Teika) and 120 parts by mass of titanium oxide particles “SMT150MK” (manufactured by Teica) were added and dispersed by a bead mill with a mill residence time of 5 hours. And after leaving this solution still overnight, it filtered, and obtained the coating liquid for intermediate | middle layer formation. Filtration was performed under a pressure of 50 kPa using a rigesh mesh filter (manufactured by Nippon Pole Co., Ltd.) having a nominal filtration accuracy of 5 μm as a filtration filter. The intermediate layer-forming coating solution thus obtained is applied to the outer peripheral surface of the washed conductive support [1] by a dip coating method and dried at 120 ° C. for 30 minutes, whereby a dry film thickness of 2 μm is obtained. An intermediate layer [1] was formed.

(3) Formation of Charge Generation Layer Dispersion for 10 hours was performed using a sand mill using the following raw materials as a disperser to prepare a charge generation layer forming coating solution [1].
Charge generation material: titanyl phthalocyanine pigment (having a maximum diffraction peak at a position of at least 27.3 ° by Cu-Kα characteristic X-ray diffraction spectrum measurement) 20 parts by mass Binder resin for charge generation layer: polyvinyl butyral resin # 6000-C "(manufactured by Denki Kagaku Kogyo Co., Ltd.) 10 parts by mass. Solvent: 700 parts by mass of t-butyl acetate. Solvent: 300 parts by mass of 4-methoxy-4-methyl-2-pentanone Above the intermediate layer [1] Then, this charge generation layer forming coating solution [1] was applied by a dip coating method to form a coating film, thereby forming a charge generation layer [1] having a dry film thickness of 0.3 μm.

(4) Formation of charge transport layer The following raw materials were mixed and dissolved to prepare a charge transport layer forming coating solution [1].
Charge transport material: 4,4′-dimethyl-4 ″-(β-phenylstyryl) triphenylamine) 225 parts by mass Binder resin for charge transport layer: polycarbonate resin “Z300” (Mitsubishi Gas Chemical Co., Ltd.) 300 mass Parts, solvent: THF 1600 parts by mass, solvent: toluene 400 parts by mass, antioxidant (BHT) 6 parts by mass, silicone oil “KF-96” (manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by mass on the charge generation layer [1] Then, this coating solution [1] for forming a charge transport layer is applied by a dip coating method to form a coating film, and this coating film is dried at 120 ° C. for 70 minutes to form a charge transport layer [1] having a layer thickness of 20 μm. Formed.

(5) Formation of protective layer Polymerizable compound (Exemplary compound (M1)) 100 parts by mass Metal oxide fine particles [1] (number average primary particle size = 30 nm) subjected to medium stirring treatment
150 parts by mass-Polymerization initiator "Irgacure 819" (manufactured by BASF Japan) 5 parts by mass-Solvent: 230 parts by mass of 2-butanol-Solvent: Tetrahydrofuran 12 parts by mass A mixture of the coating liquid composition is sufficiently stirred It melt | dissolved and disperse | distributed and the coating liquid [1] for protective layer formation was prepared.
This protective layer forming coating solution [1] is applied onto the charge transport layer [1] using a circular slide hopper applicator, irradiated with UV light for 1 minute using a xenon lamp, and then dried at 120 ° C. for 70 minutes. As a result, a protective layer [1] was formed, whereby a photoreceptor [1] was produced.

[Photosensitive body preparation examples 2, 3, and 5]
In the step of forming the protective layer in Production Example 1 of the photoreceptor, instead of the metal oxide fine particles [1] subjected to the medium stirring treatment, the metal oxide fine particles [2] and [3] subjected to the medium stirring treatment, respectively. , [4], and photosensitive members [2], [3], [5] were prepared in the same manner except that the polymerizable compounds (exemplary compounds) shown in Table 1 were used.

[Photoconductor Preparation Example 4]
Photoreceptor [4] was produced in the same manner as in Photoconductor Preparation Example 1 except that a protective layer was formed as described below. (5) Formation of protective layer-Binder resin for protective layer: polycarbonate resin " Z-300 "(manufactured by Toray Industries, Inc.)
100 parts by mass Metal oxide fine particles [1] that have been subjected to medium stirring treatment (number average primary particle size = 30 nm)
150 parts by mass-Solvent: 230 parts by mass of 2-butanol-Solvent: Tetrahydrofuran 12 parts by mass of a coating solution composition was mixed and stirred to sufficiently dissolve and disperse to prepare a protective layer forming coating solution [4].
This protective layer forming coating solution [4] is applied onto the charge transport layer [1] using a circular slide hopper coating machine and then dried at 120 ° C. for 70 minutes to form the protective layer [4]. Thus, a photoreceptor [4] was produced.

[Photoconductor Preparation Examples 6 and 7]
Except for using the metal oxide fine particles [5] and [6], respectively, instead of the metal oxide fine particles [1] subjected to the medium stirring treatment in the protective layer forming step in Preparation Example 1 of the photoreceptor. Similarly, photoreceptors [6] and [7] were produced.

[Examples 1 to 5, Comparative Examples 1 and 2]
Evaluation was performed by mounting the photoreceptors [1] to [7] on a commercially available full-color multifunction peripheral “bizhub C1070” (manufactured by Konica Minolta).
First, in an environment of a temperature of 23 ° C. and a humidity of 50% RH, an endurance test was performed in which a belt image having an image area ratio of 5% was continuously printed on both sides by 1.5 million sheets by A4 horizontal feeding. The wear resistance (surface roughness), dot reproducibility and potential stability of the body were evaluated as follows. The results are shown in Table 2.

(1) Abrasion resistance (surface roughness)
Before and after the above durability test, using a surface roughness measuring machine “Surfcom 1400D” (manufactured by Tokyo Seimitsu Co., Ltd.), reference length λc = 0.08 mm, evaluation length L = 8 mm, measurement speed = 0.15 mm / The surface roughness Rz was measured under the condition of sec.
In the present invention, a case where the difference (ΔRz) before and after the printing durability test (initial and after durability) is 0.1 or less is determined to be acceptable.

(2) Dispersibility (dot reproducibility)
After the printing durability test, in the environment of temperature 30 ° C. and humidity 80% RH, the internal mounting pattern No. 53 / Dot 1 (a typical exposure pattern formed in the form of dots having regularity) is printed on an A3 / POD gloss coated paper (100 g / m ² ) (manufactured by Oji Paper Co., Ltd.) with a density indication value of 100. The dot formation state was magnified and evaluated according to the following evaluation criteria.
-Evaluation criteria-
A: The dots are formed normally (pass)
B: Some dots are thin, but there is no practical problem (pass)
C: The dots are thin as a whole, and there are practical problems (failure)

(3) Potential stability Before and after the printing durability test, while rotating the photoconductor at 130 rpm in an environment of a temperature of 10 ° C. and a humidity of 15% RH, the grid voltage was −700 V and the exposure amount was 0.4 μJ / cm. Measure the post-exposure potential under the conditions of ² , and the difference between the post-exposure potential before the printing test (initial potential) and the post-exposure potential after the printing test (post-endurance potential) ((post-endurance potential)-(initial potential) )) Which is a potential fluctuation (ΔV) was calculated.
In the present invention, a case where the potential fluctuation is 60 V or less is determined to be acceptable.

1a Conductive support 1b Intermediate layer 1c Charge generation layer 1d Charge transport layer 1e Protective layer 1eA Metal oxide fine particles 1f subjected to medium stirring treatment Photosensitive layers 1, 1Y, 1M, 1C, 1Bk Photoconductors 2Y, 2M, 2C, 2Bk charging means 3Y, 3M, 3C, 3Bk exposure means 4Y, 4M, 4C, 4Bk developing means 5Y, 5M, 5C, 5Bk primary transfer roller 5b secondary transfer rollers 6Y, 6M, 6C, 6Bk, 6b cleaning means 10Y, 10M , 10C, 10Bk Image forming unit 20 Paper feed cassette 21 Paper feed means 22A, 22B, 22C, 22D Intermediate roller 23 Registration roller 24 Fixing means 25 Paper discharge roller 26 Paper discharge tray 70 Intermediate transfer body units 71, 72, 73, 74 Roller 77 Intermediate transfer member 80 Cases 82L, 82R Support rail A Body SC Original image reading Location P transfer material

Claims (4)

A method for producing an electrophotographic photosensitive member in which a charge generation layer, a charge transport layer and a protective layer are laminated in this order on a conductive support,
The protective layer contains metal oxide fine particles in the resin,
A method for producing an electrophotographic photoreceptor, wherein the metal oxide fine particles used are those that have been agitated with a medium in liquid nitrogen.   The method for producing an electrophotographic photosensitive member according to claim 1, wherein the metal oxide fine particles are P-type semiconductor fine particles. The method for producing an electrophotographic photosensitive member according to claim 2, wherein the P-type semiconductor fine particles are CuAlO ₂ fine particles. An electrophotographic photosensitive member in which a charge generation layer, a charge transport layer, and a protective layer are laminated in this order on a conductive support,
The protective layer contains metal oxide fine particles in the resin,
The protective layer contains metal oxide fine particles in the resin,
A method for producing an electrophotographic photosensitive member, wherein the metal oxide fine particles are subjected to a treatment of stirring together with a medium in liquid nitrogen.

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