JP2016114902A - Organic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic photoreceptor that can provide memory resistance over a long period and provide high stability in quality of an image to be formed.SOLUTION: There is provided an organic photoreceptor having a charge generating layer, charge transport layer, and protective layer laminated in this order on a conductive support, where the protective layer contains p-type semiconductor fine particles and copper (II) oxide fine particles. In the organic photoreceptor, the copper (II) oxide fine particles preferably have a number average primary particle diameter of 1 to 300 nm, and the copper (II) oxide fine particles are preferably be contained in an amount of 0.05 to 5 mass% relative to the p-type semiconductor fine particles.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an organic photoreceptor used in an electrophotographic image forming apparatus.

Organic photoconductors (hereinafter also simply referred to as “photoconductors”) constituting image forming apparatuses such as electrophotographic copying machines and printers have a long life and image quality stability of formed images. It has been demanded. In the photoconductor, the lifetime of the photoconductor is determined as the photoconductor surface wears, and image quality deterioration is caused by minute scratches and uneven wear caused by wear on the photoconductor surface.
In recent years, an organic photosensitive layer is laminated on a conductive support as a photoconductor that has excellent wear resistance, scratch resistance, and environmental stability and has a long life, and a protective layer made of a cured resin is further formed on the organic photosensitive layer. An organophotoreceptor in which is formed has been developed.

  In such an organic photoreceptor, in order to improve wear resistance and image quality stability, 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, even with a photoreceptor constituted by adding P-type semiconductor fine particles to the protective layer as described above, the memory resistance and image quality stability relating to the exposure memory and transfer memory are sufficient when used for a long period of time. The reality is that it cannot be obtained.

JP 2013-130603 A

  The present invention has been made based on the circumstances as described above, and an object of the present invention is to provide an organic photoreceptor capable of obtaining memory resistance over a long period of time and providing high image quality stability to a formed image. It is to provide.

The organic photoreceptor of the present invention is an organic 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 P-type semiconductor fine particles and copper (II) oxide fine particles in a resin.

  In the organophotoreceptor of the present invention, the copper (II) oxide fine particles preferably have a number average primary particle size of 1 to 300 nm.

  In the organophotoreceptor of the present invention, the copper (II) oxide fine particles are preferably contained in an amount of 0.05 to 5% by mass with respect to the P-type semiconductor fine particles.

  In the organic photoreceptor of the present invention, the P-type semiconductor fine particles are preferably made of a metal oxide.

In the organophotoreceptor of the present invention, the metal oxide is preferably composed of a compound represented by the following general formula (1) or a compound represented by the following general formula (2).
General formula (1): CuM ¹ O ₂
[Wherein M ¹ represents an element belonging to Group 13 of the periodic table. ]
General formula (2): M ² Cu ₂ O ₂
[Wherein M ² represents an element of Group ² of the periodic table. ]

  In the organic photoreceptor of the present invention, it is preferable that the resin constituting the protective layer is a cured resin obtained by polymerizing a crosslinkable polymerizable compound.

  According to the organophotoreceptor of the present invention, by having a protective layer containing P-type semiconductor fine particles and copper (II) oxide fine particles in the resin, memory resistance can be obtained over a long period of time and an image to be formed High image quality stability.

It is a fragmentary sectional view which shows an example of the layer structure of the organic photoreceptor of this invention. FIG. 2 is a cross-sectional view illustrating the configuration of an example of an image forming apparatus provided with the organic photoreceptor of the present invention.

  Hereinafter, the present invention will be specifically described.

[Photoconductor]
The photoreceptor of the present invention is an organic photoreceptor in which a charge generation layer, a charge transport layer, and a protective layer are laminated in this order on a conductive support.

  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.

  As the photoreceptor, for example, as shown in FIG. 1, an intermediate layer 1b, a charge generation layer 1c, a charge transport layer 1d, and a protective layer 1e are laminated in this order on a conductive support 1a. Thus formed, the charge generating layer 1c and the charge transport layer 1d constitute the organic photosensitive layer 1f that is indispensable for the structure of the organic photoreceptor. The protective layer 1e contains P-type semiconductor fine particles 1eA and copper (II) oxide fine particles 1eB.

[Protective layer 1e]
The protective layer constituting the photoreceptor of the present invention is one in which P-type semiconductor fine particles 1eA and copper (II) oxide fine particles 1eB are contained in a binder resin (hereinafter also referred to as “protective layer binder resin”). is there.
By including the P-type semiconductor fine particles 1eA and the copper oxide (II) fine particles 1eB in the protective layer 1e, the memory resistance related to the exposure memory and the transfer memory can be obtained over a long period of time, and the potential stability can be obtained. High image quality stability can be obtained for the formed image.
This is considered to be due to the following reasons. That is, first, since the copper oxide (II) fine particles 1eB have a high concealment rate for light in the wavelength range from the visible light region to the infrared light region, the influence of exposure to exposure to static electricity or exposure is reduced. Therefore, the memory resistance related to the exposure memory can be sufficiently obtained even when it is repeatedly used over a long period of time. Further, since the P-type semiconductor fine particles 1eA have a hole transport property, a good hole sweeping property from the inside of the photoreceptor can be obtained, so that a high image quality stability can be obtained in an image formed by obtaining a potential stability. . However, since the protective layer 1e contains the P-type semiconductor fine particles 1eA, it is easily affected by hole injection in the transfer process, and the memory resistance related to the transfer memory is not sufficiently secured. The inclusion of copper oxide (II) fine particles 1eB, which are high-resistance fine particles, in 1e reduces the influence of hole injection, so that the memory resistance of the transfer memory can be sufficiently obtained. In addition, when other high resistance fine particles that are not copper (II) oxide fine particles are contained in the protective layer, it is considered that sufficient potential stability cannot be obtained.

[P-type semiconductor fine particles 1eA]
P-type semiconductor fine particles are semiconductor particles in which carriers for transporting charges are holes, and contribute to image quality stability.

In the present invention, it is preferable to use metal oxide fine particles as the P-type semiconductor fine particles, and in particular, those composed of a compound represented by the following general formula (1) or a compound represented by the following general formula (2). It is preferable to be used. Further, Cu ₂ O may be used as the P-type semiconductor fine particles.
General formula (1): CuM ¹ O ₂
[Wherein M ¹ represents an element belonging to Group 13 of the periodic table. ]
General formula (2): M ² Cu ₂ O ₂
[Wherein M ² represents an element of Group ² of the periodic table. ]

Specific examples of Group 13 elements in the periodic table include boron (B), aluminum (Al), gallium (Ga), indium (In), and thallium (Tl). In the present invention, aluminum Preferably, gallium or indium is used.
In the present invention, preferred examples of the compound represented by the general formula (1) include CuAlO ₂ , CuGaO ₂ , and CuInO ₂ .

Specific examples of Group 2 elements in the periodic table include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). In the invention, barium or strontium is preferable.
In the present invention, preferred examples of the compound represented by the general formula (2) include BaCu ₂ O _{2 and} SrCu ₂ O ₂ .

  The number average primary particle size of the P-type semiconductor fine particles is preferably 1 to 300 nm, more preferably 3 to 100 nm.

  The number-average primary particle size of the P-type semiconductor fine particles is a photographic image (aggregated particles) taken with a scanning electron microscope “JSM-7500F” (manufactured by JEOL Ltd.) and a magnified image of 100,000 times taken with a scanner. The P-type semiconductor fine particles were binarized using an automatic image processing analyzer “LUZEX AP (software version Ver. 1.32)” (manufactured by Nireco). The horizontal direction ferret diameter about 100 arbitrary is calculated, and let the average value be a 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 P-type semiconductor fine particles is binarized.

The P-type semiconductor fine particles can be produced, for example, by a sintering method. Specifically, when CuAlO ₂ is used as the P-type semiconductor fine particles, Al ₂ O ₃ (purity 99.9%) and Cu ₂ O (99.9%) are mixed at a molar ratio of 1: 1, and an Ar atmosphere After calcining at a temperature of 1100 ° C. for 4 days, a sintered body is obtained by molding into a pellet and sintering at 1100 ° C. for 2 days. 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.

  The P-type semiconductor fine particles can also be generated using, for example, a plasma method. Examples of the plasma method include a direct current plasma arc method, a high frequency plasma method, and a plasma jet method.

  In the DC plasma arc method, a metal alloy is used as a consumption anode electrode, a plasma flame is generated from the cathode electrode, the metal alloy on the anode electrode side is heated and evaporated, and the vapor of the metal alloy is oxidized and cooled. Type semiconductor fine particles can be obtained.

  In the high frequency plasma method, thermal plasma generated when a gas is heated by high frequency induction discharge under atmospheric pressure is used. Of these, in the plasma evaporation method, solid particles are injected into the center of the inert gas plasma, evaporated while passing through the plasma, and P-type semiconductor fine particles can be generated by rapidly cooling and condensing the high-temperature vapor.

In the plasma method, argon plasma, hydrogen (nitrogen, oxygen) plasma, or the like is obtained by arc discharge in an inert gas argon and hydrogen or nitrogen as a diatomic molecular gas in an oxygen atmosphere. Since hydrogen (nitrogen, oxygen) plasma is extremely reactive compared to inert gas, it is called reactive arc plasma to distinguish it from inert gas plasma.
As a method for generating P-type semiconductor fine particles, a plasma method using oxygen plasma among reactive arc plasmas can be suitably used.

The P-type semiconductor fine particles 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 P-type semiconductor fine particles is 20 parts by mass or more with respect to 100 parts by mass of the binder resin for the protective layer, the charge transport ability can be reliably obtained in the protective layer. On the other hand, the content ratio of the P-type semiconductor fine particles is 300 parts by mass or less with respect to 100 parts by mass of the binder resin for the protective layer, thereby preventing the formation of the coating film from being inhibited when the protective layer is formed. Can do.

[Surface-treated P-type semiconductor fine particles]
The P-type semiconductor fine particles contained in the protective layer are preferably surface-treated with a surface treatment agent from the viewpoint of obtaining dispersibility and improving wear resistance, and further have a surface having a reactive organic group It is more preferable that the surface is treated with a treatment agent.

As the surface treatment agent, it is preferable to use a surface treatment agent that reacts with a hydroxy group or the like present on the surface of the P-type semiconductor fine particles before the treatment. Etc.
In the present invention, for the purpose of further increasing the hardness of the protective layer, it is preferable to use a surface treating agent having a reactive organic group, and it is more preferable that the reactive organic group is a radically polymerizable reactive group. preferable. By using a surface treating agent having a radical polymerizable reactive group, when the protective layer binder resin is a cured resin of the following polymerizable compound, it forms a strong protective layer to react with the polymerizable compound. Can do.
As the surface treatment agent having a radical polymerizable reactive group, a silane coupling agent having an acryloyl group or a methacryloyl group is preferably used, and the surface treatment agent having such a radical polymerizable reactive group is described below. Such known compounds are exemplified.
Examples of the silane coupling agent having an acryloyl group or a methacryloyl group include the following compounds.

_{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 P-type semiconductor fine particles before a process.

[Surface treatment method for P-type semiconductor fine particles]
Specifically, the surface treatment of the P-type semiconductor fine particles is performed by wet-grinding a slurry (suspension of solid particles) containing the P-type semiconductor fine particles and the surface treatment agent before the treatment, thereby finely dividing the P-type semiconductor fine particles. At the same time, the surface treatment of the particles proceeds, and then the solvent is removed to form a powder.

  The slurry is preferably mixed at a ratio of 0.1 to 100 parts by mass of the surface treatment agent and 50 to 5000 parts by mass of the solvent with respect to 100 parts by mass of the P-type semiconductor fine particles before treatment.

An apparatus used for wet pulverization of the slurry includes a wet media dispersion type apparatus.
The wet media dispersion type device is a method of crushing and dispersing the aggregated particles of P-type semiconductor fine particles by filling beads in a container as media and rotating a stirring disk mounted perpendicular to the rotation axis at high speed. There is no problem as long as it is a type in which the P-type semiconductor fine particles are sufficiently dispersed and surface-treated when the surface treatment is performed on the P-type semiconductor fine particles. Various types such as a continuous type and a batch type can be used. Specifically, a sand mill, an ultra visco mill, a pearl mill, a glen mill, a dyno mill, an agitator mill, a dynamic mill, or 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.

  As the beads used in the wet media dispersion type apparatus, a ball made of glass, alumina, zircon, zirconia, steel, flint stone or the like can be used, but those made of zirconia or zircon are particularly preferable. Further, as the size of the beads, those having a diameter of about 1 to 2 mm are usually used, but in the present invention, those having a diameter of about 0.1 to 1.0 mm are preferably used.

  Various materials such as stainless steel, nylon, and ceramic can be used for the disk and container inner wall used in the wet media dispersion type apparatus. In the present invention, a ceramic disk such as zirconia or silicon carbide is particularly used. Or the inner wall of the container.

[Copper (II) oxide fine particles 1eB]
The copper (II) oxide fine particles 1eB contained in the protective layer 1e of the organophotoreceptor of the present invention may be one that has been surface-treated with a surface treatment agent. The surface treatment agent used for the surface treatment of the copper (II) oxide fine particles may be a surface treatment agent having a reactive organic group.
The surface treatment of the copper (II) oxide fine particles can be performed by the same method as for the P-type semiconductor fine particles.

The number average primary particle size of the copper (II) oxide fine particles is preferably 1 to 300 nm, more preferably 3 to 100 nm.
When the number average primary particle size of the copper (II) oxide fine particles is 1 nm or more, sufficient dispersion stability is obtained in the coating solution for forming the protective layer, and the coating solution is stably maintained for a long period of time. be able to. On the other hand, when the number average primary particle size of the copper (II) oxide fine particles is 300 nm or less, the roughness of the surface of the coating film for forming the protective layer can be suppressed to a low level, and as a result It is possible to make the body suppressed from occurrence of poor cleaning.
The number average primary particle size of the copper (II) oxide fine particles is measured in the same manner as the P-type semiconductor fine particles.

The copper (II) oxide fine particles are preferably contained in a proportion of 0.05 to 5% by mass, more preferably 0.1 to 3% by mass with respect to the P-type semiconductor fine particles.
When the content ratio of the copper (II) oxide fine particles is 0.05% by mass or more with respect to the P-type semiconductor fine particles, the memory resistance related to the exposure memory and the transfer memory can be sufficiently obtained. On the other hand, when the content ratio of the copper (II) oxide fine particles is 5% by mass or less with respect to the P-type semiconductor fine particles, it is possible to suppress a decrease in the light transmittance of the protective layer and to reduce the sensitivity of the photoreceptor. And the increase in potential after exposure can be suppressed.

[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—).

  In addition to the protective layer binder resin, P-type semiconductor fine particles, and copper (II) oxide fine particles as described above, the protective layer may contain lubricant particles, various antioxidants, and the like as necessary. Good.

[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 be used singly or in combination of two or more. 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 obtained by adding a polyfunctional radical polymerizable compound, P-type semiconductor fine particles and copper (II) oxide fine particles, and a known resin, a polymerization initiator, lubricant particles, an antioxidant, etc. to a solvent as necessary. The prepared coating solution can be produced by coating the surface of the charge transport layer by a known method to form a coating film, followed by curing treatment.

(Polymerization initiator)
The polymerization initiator that can be contained in the protective layer is a radical polymerization initiator that initiates the polymerization reaction of the polyfunctional radical polymerizable compound, and examples thereof include a thermal polymerization initiator and a photopolymerization 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.

  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 solvent used for forming the intermediate layer is not particularly limited. For example, n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, methyl ethyl ketone, methyl isopropyl ketone, Cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane, tetrahydrofuran, dioxolane, Use dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cellosolve, etc. It can, among these, toluene, tetrahydrofuran, dioxolane, etc. are preferably used. These solvents can be used alone or as a mixed solvent 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.

  Although it does not specifically limit as a coating method of the coating liquid for intermediate | middle layer formation, For example, the dip coating method, the spray coating method, etc. are mentioned.

  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 content ratio of the charge generation material in the charge generation layer is preferably 1 to 600 parts by mass, more preferably 50 to 500 parts by mass with respect to 100 parts by mass of the binder resin for charge generation layer.

  The mixing ratio of the charge generation layer binder resin and the charge generation material is preferably 20 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 binder resin for the charge generation layer may be used. For example, ketone solvents such as methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, cyclohexanone, acetophenone, etc. , Ether solvents such as tetrahydrofuran, dioxolane and diglyme, alcohol solvents such as methyl cellosolve, ethyl cellosolve and butanol, ester solvents such as ethyl acetate and t-butyl acetate, aromatic solvents such as toluene and chlorobenzene, A large number of halogen-based solvents such as dichloroethane and trichloroethane can be exemplified, but the invention is not limited thereto. 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 layer thickness of the charge generation layer varies depending on the characteristics of the charge generation material, the characteristics and content ratio of the binder resin for the charge generation layer, but is preferably 0.1 to 2 μm, more preferably 0.15 to 1.5 μm. is there.

[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”).

  Examples of the charge transport material for the charge transport layer include a charge transport material such as a triphenylamine derivative, a hydrazone compound, a styryl compound, a benzidine compound, and a butadiene compound.

  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 250 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, and 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.

  According to the photoreceptor as described above, by having the protective layer 1e in which the P-type semiconductor fine particles 1eA and the copper (II) oxide fine particles 1eB are contained in the resin, the memory resistance can be obtained over a long period of time. High image quality stability can be obtained for the image to be displayed.

[Image forming apparatus]
The photoreceptor of the present invention can be provided in a general electrophotographic image forming apparatus. Examples of such an image forming apparatus include a photoconductor, a charging unit that charges the surface of the photoconductor, an exposure unit that forms an electrostatic latent image on the surface of the photoconductor, and the electrostatic latent image using toner. Developing means for developing and forming a toner image, transfer means for transferring the toner image to a transfer material, fixing means for fixing the toner image transferred to the transfer material, and cleaning means for removing residual toner on the photoreceptor And the like provided with.

FIG. 2 is a cross-sectional view illustrating the configuration of an example of an image forming apparatus provided with the photoconductor of 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 endless belt-shaped intermediate transfer body unit 7, and paper feeding It comprises means 21 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, The rotating developing means 4Y, 4M, 4C, 4Bk and the cleaning means 6Y, 6M, 6C, 6Bk for cleaning the photoreceptors 1Y, 1M, 1C, 1Bk are configured.
The image forming apparatus of the present invention uses the above-described photoreceptor 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 image forming unit 10Y will be described in detail as an example.

  In the image forming unit 10Y, a charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 6Y are arranged around a photoconductor 1Y as an image forming body, and a yellow (Y) toner image is placed on the photoconductor 1Y. To form.

  The charging unit 2Y is a unit that applies a uniform potential to the photoreceptor 1Y. In the present invention, the charging means includes a contact or non-contact roller charging type.

  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 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.

  The cleaning unit 6Y 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 apparatus main body A through a guide means such as a rail.

  The image forming units 10Y, 10M, 10C, and 10Bk are arranged in a column in the vertical direction, and an endless belt-shaped intermediate transfer body unit 7 is arranged on the left side of the photoreceptors 1Y, 1M, 1C, and 1Bk in the drawing. The endless belt-shaped intermediate transfer body unit 7 is wound around a primary transfer roller 5Y, 5M, 5C, 5Bk, a secondary transfer roller 5b, and a plurality of rollers 71, 72, 73, 74, and is rotatably supported. Further, it comprises a semiconductive endless belt-shaped intermediate transfer body 70 and a cleaning means 6b.

  The image forming units 10Y, 10M, 10C, and 10Bk and the endless belt-shaped intermediate transfer body unit 7 are housed in a housing 8, and the housing 8 is pulled out from the apparatus main body A through support rails 82L and 82R. It is configured to be possible.

  The toner images of the respective colors formed by the image forming units 10Y, 10M, 10C, and 10Bk are sequentially transferred onto a rotating endless belt-shaped intermediate transfer body 70 by primary transfer rollers 5Y, 5M, 5C, and 5Bk as primary transfer means. The image is transferred and superimposed to form a color image. Then, a transfer material (image support that carries a fixed final image: for example, plain paper, transparent sheet, etc.) P housed 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 means, and a color image is collectively transferred onto the transfer material P. The transfer material P onto which the color image has been transferred is subjected to fixing processing by the fixing unit 24, is sandwiched between paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus.

  On the other hand, after the color 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 endless belt-shaped intermediate transfer body 70 from which the transfer material P is separated by curvature.

  During the image forming process, the primary transfer roller 5Bk is always in contact with the photoconductor 1Bk, and the other primary transfer rollers 5Y, 5M, and 5C are respectively provided with the corresponding photoconductors 1Y, 1M, and 5D only when forming a color image. 1C is contacted.

  The secondary transfer roller 5b is brought into contact with the endless belt-shaped intermediate transfer member 70 only when the transfer material P passes through the secondary transfer roller 5b.

  In the image forming apparatus shown in FIG. 2, a color laser printer is shown. However, the photoconductor of the present invention can be similarly applied to a monochrome laser printer and a copy. Moreover, as an exposure light source, you may use light sources other than a laser, for example, LED light source.

[Toner and developer]
The toner used in the image forming apparatus provided with the photoconductor of the present invention may be a pulverized toner or a polymerized toner. However, in the image forming apparatus according to the present invention, from the viewpoint of obtaining a high quality image. It is preferable to use a polymerized toner prepared by a polymerization method.

  With polymerized toner, the generation of the binder resin that forms the toner and the formation of the toner particle shape are performed in parallel by polymerization of the raw material monomer to obtain the binder resin and, if necessary, subsequent chemical treatment. It means the resulting toner.

  More specifically, it means a toner formed through a step of obtaining resin fine particles by a polymerization reaction such as suspension polymerization or emulsion polymerization, and a step of fusing the resin fine particles performed thereafter if necessary.

  As the toner used in the image forming apparatus provided with the photoreceptor of the present invention, it is preferable to use a toner in which the binder resin is made of a crystalline resin. By using a toner containing a binder resin made of a crystalline resin, it is possible to suppress the occurrence of fog in the obtained image. This is considered to be due to the reduction in charging variation when the toner is frictionally charged in the developing means 4Y, 4M, 4C, and 4Bk.

  The volume average particle diameter of the toner, that is, the 50% volume particle diameter (Dv50) is preferably 2 to 9 μm, more preferably 3 to 7 μm. By setting this range, the resolution can be increased. In addition, by combining with the above range, the amount of toner having a fine particle diameter can be reduced while being a small particle diameter toner, the dot image reproducibility is improved over a long period of time, and the sharpness is excellent. In addition, a stable image can be formed.

  The toner according to the present invention may be used alone as a one-component developer, or may be mixed with a carrier and used as a two-component developer.

  When used as a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used. be able to.

  In addition, when used as a two-component developer by mixing with a carrier, conventionally known magnetic particles of the carrier, such as metals such as iron, ferrite, and magnetite, alloys of these metals with metals such as aluminum and lead, etc. Materials can be used, and ferrite particles are particularly preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 80 μm.

  The volume average particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

  The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene acrylic resin, silicone resin, ester resin, or fluorine-containing polymer resin is used. The resin for constituting the resin-dispersed carrier is not particularly limited, and known resins can be used. For example, styrene acrylic resin, polyester resin, fluorine resin, phenol resin, etc. can be used. it can.

  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.

[Photosensitive body preparation example 1]
(1) Production of conductive support The surface of a drum-shaped aluminum support (outer diameter 60 mm) was cut to produce a conductive support [1].

(2) Formation of intermediate layer Binder resin for intermediate layer: Polyamide resin “CM8000” (manufactured by Toray Industries, Inc.) 100 parts by mass, ethanol / n-propyl alcohol / tetrahydrofuran (volume ratio 45/20/35) mixed solvent 1700 mass The mixture was stirred and mixed at 20 ° C. To this solution, 120 parts by mass of titanium oxide particles “SMT500SAS” (manufactured by Teica) and 160 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 layer 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-Binder resin for protective layer: Polycarbonate resin "Z-300" (manufactured by Toray Industries, Inc.)
100 parts by mass-Surface-treated P-type semiconductor fine particles (CuAlO ₂ , number average primary particle size = 20 nm)
100 parts by mass-Copper (II) oxide fine particles (number average primary particle size = 20 nm) 0.1 part by mass-Solvent: 330 parts by mass of 2-butanol-Solvent: Tetrahydrofuran 17 parts by mass of a coating liquid composition is mixed and stirred. Were sufficiently dissolved and dispersed to prepare a coating solution [1] for forming a protective layer.
The protective layer-forming coating solution [1] is applied onto the charge transport layer [1] using a circular slide hopper coating machine, and then dried at 120 ° C. for 70 minutes, whereby a protective layer having a dry film thickness of 3.0 μm is obtained. [1] was formed, thereby producing a photoreceptor [1].

[Photoconductor Preparation Example 2]
Photosensitive member [2] was prepared in the same manner as in Preparation Example 1 of the photosensitive member, except that a protective layer was formed as follows.
(5) Formation of protective layer Polymerizable compound (Exemplary compound (M1)) 100 parts by mass Surface-treated P-type semiconductor fine particles (CuAlO ₂ , number average primary particle size = 20 nm)
100 parts by mass Copper oxide (II) fine particles (number average primary particle size = 20 nm) 0.1 part by mass Polymerization initiator “Irgacure 819” (manufactured by BASF Japan) 5 parts by mass Solvent: 2-butanol 330 mass Part-Solvent: Tetrahydrofuran A coating liquid composition consisting of 17 parts by mass was mixed and stirred to sufficiently dissolve and disperse to prepare a coating liquid [2] for forming a protective layer.
This protective layer forming coating solution [2] 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 [2] having a dry film thickness of 3.0 μm was formed, whereby a photoreceptor [2] was produced.

[Photoconductor Preparation Example 3]
Photosensitive member [3] was prepared in the same manner as in Preparation Example 1 of the photosensitive member, except that a protective layer was formed as described below.
(5) Formation of protective layer Polymerizable compound (Exemplary compound (M1)) 100 parts by mass Surface-treated P-type semiconductor fine particles (CuAlO ₂ , number average primary particle size = 20 nm)
100 parts by mass Copper oxide (II) fine particles (number average primary particle size = 20 nm) 0.1 part by mass Polymerization initiator: 5 parts by mass of the compound represented by the following formula (A) Solvent: 2-butanol 330 parts by mass Solvent: Tetrahydrofuran 17 parts by weight of a coating solution composition was mixed and stirred to sufficiently dissolve and disperse to prepare a protective layer forming coating solution [3].
This protective layer-forming coating solution [3] is applied onto the charge transport layer [1] using a circular slide hopper coating machine, and then dried at 120 ° C. for 70 minutes, thereby protecting the film with a dry film thickness of 3.0 μm. Layer [3] was formed, thereby producing photoreceptor [3].

[Photoconductor Preparation Examples 4 to 10]
Photoreceptors [4] to [10] were produced in the same manner as in the protective layer formation step in Photoreceptor Production Example 2, except that the formulation in Table 1 was changed.

[Production Example 11 of Photoreceptor]
A comparative photoconductor [11] was produced in the same manner as in the protective layer forming step in Photoconductor Production Example 2 except that copper (II) oxide fine particles were not added.

[Photoconductor Preparation Example 12]
In the protective layer forming step in Photosensitive Member Preparation Example 2, for the purpose of comparison, except that Fe ₂ O ₃ fine particles (number average primary particle size = 20 nm) were added instead of copper (II) oxide fine particles. The photoreceptor [12] was prepared.

[Examples 1 to 10, Comparative Examples 1 and 2]
Evaluation was performed by mounting the photoreceptors [1] to [12] on a commercially available full-color multifunction peripheral “bizhub PRO C6501” (manufactured by Konica Minolta).
First, in a temperature 23 ° C. and humidity 50% RH environment, 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 million sheets at A4 horizontal feed, and before and after the endurance test. The transfer memory, the exposure memory, and the potential stability were evaluated.

(1) Evaluation of transfer memory After the endurance test, the transfer current was changed between 20 μA and 100 μA, 10 images in which a solid black image and a solid white image were mixed were continuously printed, and then uniform halftone An image was printed, and the occurrence of a solid black image and a solid white image in the halftone image, that is, the occurrence of memory, was visually observed and evaluated according to the following evaluation criteria. The results are shown in Table 2.
-Evaluation criteria-
A: Even when the transfer current exceeds 60 μA, no memory is observed (pass)
B: A slight memory is observed when the transfer current is in the range of 40 to 60 μA, but there is no practical problem (pass).
C: Even when the transfer current is less than 40 μA, the memory is clearly observed and is a practically problematic level (failed)

(2) Evaluation of exposure memory After the endurance test, 20,000 black solid band charts were continuously printed on A3 paper, and then a uniform halftone image was printed. The history of the black solid band chart was included in this halftone image. Occurrence, that is, occurrence of memory, was visually observed. When memory was generated, A3 halftone images were output every 5 minutes thereafter, and the recovery time was investigated and evaluated according to the following evaluation criteria. The results are shown in Table 2.
-Evaluation criteria-
A: No memory is observed even immediately after continuous printing of 20,000 sheets (pass)
B: Memory is observed immediately after continuous printing of 20,000 sheets, but recovers within 5 minutes, and there is no practical problem (pass)
C: Memory is observed immediately after continuous printing of 20,000 sheets, and does not recover even after a time exceeding 5 minutes, causing a practical problem (fail)

(3) Evaluation of potential stability Before and after the durability test, while rotating the organic photoreceptor 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 ^2. Measure the post-exposure potential under the following conditions: the difference between the post-exposure potential before the endurance test (initial potential) and the post-exposure potential after the endurance test (post-endurance potential) ((post-endurance potential)-(initial potential)) A certain potential fluctuation (ΔV) was calculated and evaluated. The results are shown in Table 2. 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 P-type semiconductor fine particles 1eB copper (II) oxide fine particles 1f organic 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 7 Endless belt-shaped intermediate transfer body unit 8 Housing 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 Endless belt-shaped intermediate transfer member 71, 72, 73, 74 Roller 82L, 82R Support rail A Main unit SC Document image reading device P Transfer material

Claims (6)

In an organic photoreceptor in which a charge generation layer, a charge transport layer and a protective layer are laminated in this order on a conductive support,
An organic photoreceptor, wherein the protective layer contains P-type semiconductor fine particles and copper (II) oxide fine particles in a resin.   2. The organophotoreceptor according to claim 1, wherein the copper (II) oxide fine particles have a number average primary particle size of 1 to 300 nm.   The organophotoreceptor according to claim 1, wherein the copper (II) oxide fine particles are contained in an amount of 0.05 to 5 mass% with respect to the P-type semiconductor fine particles.   The organophotoreceptor according to claim 1, wherein the P-type semiconductor fine particles are made of a metal oxide. The organophotoreceptor according to claim 4, wherein the metal oxide is composed of a compound represented by the following general formula (1) or a compound represented by the following general formula (2).
General formula (1): CuM ¹ O ₂
[Wherein M ¹ represents an element belonging to Group 13 of the periodic table. ]
General formula (2): M ² Cu ₂ O ₂
[Wherein M ² represents an element of Group ² of the periodic table. ] 6. The organic photoreceptor according to claim 1, wherein the resin constituting the protective layer is a cured resin obtained by polymerizing a crosslinkable polymerizable compound.

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