JP2005292821A - Electrophotographic photoreceptor, and image forming apparatus and cartridge using photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having excellent electric characteristics as well as image characteristics in various use environments with high temperature and high humidity to low temperature and low humidity, and to provide an image forming apparatus and a cartridge using the electrophotographic photoreceptor. <P>SOLUTION: The electrophotographic photoreceptor is an organic electrophotographic photoreceptor having a base coating layer and a photosensitive layer on a conductive substrate, wherein the base coating layer contains a binder resin and metal compound particles having an organic group containing a sulfur atom. The invention provides an image forming apparatus using the above photoreceptor and provides a cartridge for the apparatus. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photosensitive member having an undercoat layer, and more particularly to an electrophotographic photosensitive member having good electrical characteristics and image characteristics.

In recent years, electrophotographic technology has been widely used and applied not only in the field of copying machines but also in the field of various printers because of its immediacy and high-quality images.
As for photoconductors that are the core of electrophotographic technology, in recent years, photoconductors using organic photoconductive materials that have advantages such as non-polluting, easy film formation, and easy manufacture are available. Has been developed. In particular, a stacked type photoconductor composed of a charge generation layer and a charge transfer layer, which separates the function of absorbing light to generate charges and the function of transporting the generated charges, has become the mainstream. Currently, these photoreceptors are widely used in the field of image forming apparatuses such as copying machines and laser printers.

The electrophotographic photosensitive member has a basic structure in which a photosensitive layer is formed on a conductive support. An undercoat layer is provided between the photosensitive layer and the support in order to eliminate image defects due to charge injection from the support or defects in the support, and to improve the adhesion to the photosensitive layer to improve the chargeability. Yes.
As the undercoat layer, it is known to use various resin materials, and it is known that a soluble polyamide resin is particularly preferable (see, for example, Patent Document 1). As a particularly preferable polyamide resin, a copolymerized polyamide resin having a specific diamine component as a constituent component is known (see, for example, Patent Document 2). Further, as an undercoat layer in which an inorganic material is dispersed in a polyamide resin, for example, a layer in which titanium oxide and tin oxide are dispersed in 8-nylon is known (see, for example, Reference 3).
JP 56-21129 A JP-A-4-31870 Japanese Patent Laid-Open No. 62-280864

  However, in the electrophotographic photosensitive member using the previously known undercoat layer, the electrical characteristics and image characteristics are highly dependent on the environment, and it is difficult to obtain a high-quality image. For example, when using the undercoat layer according to the technique described in JP-A-62-258471, the thicker the undercoat layer is, the better the image characteristics are. It deteriorates rapidly especially in a low temperature and low humidity environment. On the other hand, when the film thickness of the undercoat layer was reduced, the residual potential was improved, but the image defects could not be sufficiently eliminated and the characteristics could not be achieved at the same time.

  Similarly, for example, when fine particles of titanium oxide that have not been surface-treated are dispersed as metal compound particles, the residual potential in a low-humidity environment certainly improves, but conversely the image characteristics under high-temperature and high-humidity conditions deteriorate. Therefore, even if the film thickness was increased, it could not be improved sufficiently. The same was true for the dispersion of titanium oxide subjected to alumina surface treatment. Dispersed titanium oxide treated only with methylhydrogen siloxane, dispersed untreated titanium oxide, dispersed alumina-treated titanium oxide, and treated with alumina and further treated with methylhydrogen polysiloxane Compared to the above, the improvement in characteristics was observed, but it was insufficient.

  The present invention provides an electrophotographic photoreceptor excellent in electrical characteristics and image characteristics under various usage environments ranging from high temperature and high humidity to low temperature and low humidity, and an image forming apparatus using the electrophotographic photoreceptor. It is for the purpose.

  As a result of intensive studies on materials used for the undercoat layer of the electrophotographic photoreceptor, the present inventors have found that a photoreceptor using an undercoat layer containing a metal compound particle having an organic group containing a sulfur atom and a binder resin, It has been found that it has excellent electrical characteristics and image characteristics, and has reached the present invention. That is, the gist of the present invention is an organic electrophotographic photoreceptor having an undercoat layer and a photosensitive layer on a conductive substrate, wherein the undercoat layer contains metal compound particles having an organic group containing a sulfur atom, and a binder resin. An electrophotographic photosensitive member characterized by the above.

  The electrophotographic photoreceptor using the undercoat layer of the present invention has good adhesion to the photosensitive layer and the conductive substrate in various usage environments ranging from high temperature and high humidity conditions to low temperature and low humidity conditions, High performance electrophotographic photoreceptor excellent in electrical characteristics such as chargeability and residual potential, and image characteristics, high performance image forming apparatus using the photoreceptor, and image forming apparatus using the photoreceptor A cartridge can be provided.

Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is a representative example of the embodiments of the present invention, and is appropriately modified and implemented without departing from the spirit of the present invention. can do.
In the present invention, a metal compound particle having an organic group containing a sulfur atom and an undercoat layer containing a binder are formed on a conductive support. Here, the state in which the metal compound particle has an organic group containing a sulfur atom only needs to have an organic group containing a sulfur atom in the entire metal compound particle, more specifically, an organic compound containing a sulfur atom. The group may be chemically bonded to the surface of the metal compound particle, or the compound having an organic group containing a sulfur atom may be only attached to the surface of the metal compound particle. The state in which the compound having an organic group containing a sulfur atom is attached to the surface of the metal compound particle is not limited to the physical adsorption state, and may be a chemical adsorption state.

  In the present invention, as the organic group containing a sulfur atom contained in the metal compound particles, any organic compound containing a sulfur atom in the molecular structure can be used, and an organic sulfur halide, thiol, Examples thereof include sulfide, polysulfide, hydropolysulfide, thioaldehyde, thioketone, thioacetal, sulfoxide, sulfone, sulfonium, sultone, sultam, sulfonic acid, sulfinic acid, sulfenic acid, thiocarboxylic acid, and thiocarbonic acid derivative. These residues may also be used. Among these, thiol, sulfide, polysulfide, hydropolysulfide, and these residues are preferable, thiol, hydropolysulfide, and their residues are more preferable, and organic silicon containing a sulfur atom such as silathian is more preferable. Compounds and their residues, particularly organosilicon compounds having a mercapto group and their residues are preferred. Examples of the organosilicon compound skeleton include reactive silane coupling agents such as vinyl silane compounds, amino silane compounds, and acrylic silane compounds, and mercapto silane compounds containing mercapto groups and their residues are most preferred.

  As the metal compound particles of the present invention, those having high dispersion stability of the coating solution are preferable, and specifically, those such as silica, alumina, titanium oxide, barium titanate, zinc oxide, lead oxide, and indium oxide are used. Among these, silica, alumina, titanium oxide, zinc oxide, barium titanate and the like are preferable, and titanium oxide is particularly preferable.

Titanium oxide can be either crystalline or amorphous, but in the case of crystalline, the crystalline form may be any of anatase, rutile, or brookite, but anatase for reasons such as water absorption and surface treatment efficiency. A type or rutile type is generally used. Particularly preferably, a rutile type is used.
As for the particle size of the metal compound particles, those having an average particle size of usually 100 nm or less are preferable, and 10 to 60 nm is particularly preferable, for the reason of dispersion stability in the coating solution. The particle size of the particles used in the coating solution may be uniform or a composite system having different particle sizes. In the case of a composite system having different particle sizes, those having a maximum particle size peak near 150 nm and a particle size distribution with a minimum particle size of about 30 nm to about 500 nm are preferable. And 0.03 μm may be mixed and used.

  The metal compound particles treated with the organic compound containing a sulfur atom of the present invention (hereinafter sometimes referred to as a surface treating agent) can be produced by a dry process and a wet process. That is, in the dry method, the surface treatment agent of the present invention can be manufactured by a method in which a metal compound is coated by mixing with metal compound particles, and heat treatment is performed as necessary. In the wet method, a mixture of the metal compound particles and the surface treatment agent of the present invention in an appropriate solvent is stirred well until it is uniformly attached, or mixed with media, then dried, and heated as necessary. It can manufacture by the method of processing.

By treating with the surface treating agent of the present invention, the organosilicon compound containing sulfur atoms is firmly bonded to the surface of the metal compound particles, and the dispersion stability, low water absorption, and good electrical properties of the coating liquid containing the particles are obtained. Demonstrate.
As for the amount of the surface treatment agent, the effect of the present invention cannot be obtained when the treatment amount is small, and if the treatment amount is too large, the electrical characteristics tend to deteriorate. Furthermore, when the amount of treatment is too large, there is a treatment agent that is not modified on the surface of the particles, which causes repelling of the coating film during the coating process. Therefore, the amount of the surface treatment agent is preferably adjusted according to the type of metal compound particles, and is usually 0.1 parts by weight or more, preferably 0.2% by weight or more, based on the metal compound particles used. The surface treatment agent is treated with 20% by weight or less, preferably 10% by weight or less.

  As the binder resin contained in the undercoat layer of the electrophotographic photosensitive member of the present invention, resin materials such as polyvinyl acetal, polyamide resin, phenol resin, polyester, epoxy resin, polyurethane, and polyacrylic acid can be used. Among these, a polyamide resin having excellent adhesion to the support and low solubility in a solvent used in the charge generation layer coating solution is preferable. Among these, a copolymerized polyamide resin having a diamine component represented by the following general formula (2) as a constituent material is particularly preferable.

In formula (2), A and B each independently represent a cyclohexane ring which may have a substituent, and X represents a methylene group which may have a substituent.
The ratio between the metal compound particles treated with the surface treatment agent and the binder resin can be arbitrarily selected, but it is 0.5 weight with respect to 1 part by weight of the binder resin in terms of liquid stability, coatability, and electrical characteristics. A range of from 6 parts to 6 parts by weight is preferred. The undercoat layer is mainly composed of metal compound particles coated with an organic compound containing sulfur atoms and a binder resin, but if necessary, other surface-treated metal compound particles (fluorine silane-treated titanium oxide, methyl Dimethoxysilane-treated titanium oxide, etc.), metal compound particles without surface treatment, antioxidants, additives, conductive agents and the like may be added.

If the film thickness of the undercoat layer is too thin, the effect on local charging failure will not be sufficient, and conversely if it is too thick, the residual potential will increase or the adhesive strength between the conductive substrate and the photosensitive layer will decrease. Cause. In the present invention, the thickness of the undercoat layer is preferably 0.1 to 10 μm, more preferably 0.3 to 6 μm.
The volume resistance value of the undercoat layer is usually 1 × 10 ¹¹ Ω or more, preferably 1 × 10 ¹² Ω or more, and usually 1 × 10 ¹⁴ Ω or less, preferably 1 × 10 ¹³ Ω or less.

To obtain a subbing coating solution containing metal compound particles coated with an organic compound containing sulfur atoms and a binder resin, pulverization or dispersion treatment of planetary mill, ball mill, sand mill, paint shaker, attractor, ultrasonic, etc. The slurry of the metal compound particles treated with the apparatus may be mixed with a binder resin or a solution obtained by dissolving the binder resin in an appropriate solvent, and dissolved and stirred. Conversely, the metal compound particles may be added to the binder resin solution, and pulverization or dispersion treatment may be performed with the dispersing apparatus as described above.
<Electrophotographic photoreceptor>
A photosensitive layer is formed on the undercoat layer. The photosensitive layer may have a single layer structure, but a laminated structure in which a charge generation layer and a charge transport layer are separated is preferable. The structure of the electrophotographic photoreceptor of the present invention is not particularly limited as long as a photosensitive layer is provided on a conductive support (substrate).
<Conductive support>
There is no particular limitation on the conductive support, but for example, metal materials such as aluminum, aluminum alloy, stainless steel, copper, and nickel, and conductive powder such as metal, carbon, and tin oxide are added to impart conductivity. A resin material, a resin, glass, paper, or the like on which a conductive material such as aluminum, nickel, or ITO (indium tin oxide) is deposited or applied on the surface is mainly used. These may be used alone or in combination of two or more in any combination and ratio. As a form of the conductive support, a drum form, a sheet form, a belt form or the like is used. Further, a conductive material having an appropriate resistance value may be used on a conductive support made of a metal material in order to control conductivity and surface properties and to cover defects.

Moreover, when using metal materials, such as an aluminum alloy, as an electroconductive support body, you may use, after giving an anodic oxide film. When an anodized film is applied, it is desirable to perform a sealing treatment by a known method.
The surface of the support may be smooth, or may be roughened by using a special cutting method or by performing a roughening treatment. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the support. In order to reduce the cost, it is possible to use the drawing tube as it is without performing the cutting process.
<Photosensitive layer>
As a type of the photosensitive layer, a charge generation material and a charge transport material are present in the same layer and are dispersed in a binder resin, a charge generation layer in which a charge generation material is dispersed in a binder resin, and a charge. A function separation type (laminated type) composed of two layers of a charge transport layer in which a transport material is dispersed in a binder resin can be mentioned, but any type may be used.

In addition, as the laminated photosensitive layer, a charge generation layer and a charge transport layer are laminated in this order from the conductive support side, and a charge transport layer and a charge generation layer are laminated in this order. There are reverse laminated type photosensitive layers, and any of them can be adopted, but a forward laminated type photosensitive layer capable of exhibiting the most balanced photoconductivity is preferable.
<Laminated photosensitive layer>
-Charge generation layer In the case of a multilayer type photoreceptor (function separation type photoreceptor), the charge generation layer is formed by binding a charge generation material with a binder resin.

  Examples of the charge generation material include inorganic photoconductive materials such as selenium and its alloys, cadmium sulfide, and organic photoconductive materials such as organic pigments, but organic photoconductive materials are preferred, especially organic pigments. Is preferred. Examples of organic pigments include phthalocyanine pigments, azo pigments, dithioketopyrrolopyrrole pigments, squalene (squarylium) pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, and benzimidazole pigments. . Among these, phthalocyanine pigments or azo pigments are particularly preferable. When organic pigments are used as the charge generating substance, usually, fine particles of these organic pigments are used in the form of a dispersion layer bound with various binder resins.

  When a metal-free phthalocyanine compound or a metal-containing phthalocyanine compound is used as the charge generation material, a photosensitive member having a high sensitivity to a laser beam having a relatively long wavelength, for example, a laser beam having a wavelength around 780 nm, is obtained. When an azo pigment such as diazo or trisazo is used, it is sufficient for white light, laser light having a wavelength around 660 nm, or laser light having a relatively short wavelength, for example, laser having a wavelength around 450 nm or 400 nm. A photosensitive member having a high sensitivity can be obtained.

When an organic pigment is used as the charge generating material, a phthalocyanine pigment or an azo pigment is particularly preferable. The phthalocyanine pigment provides a photosensitive material with high sensitivity to a laser beam having a relatively long wavelength, and the azo pigment has a sufficient sensitivity to white light and a laser beam having a relatively short wavelength. , Each is excellent.
When using a phthalocyanine pigment as a charge generation material, specifically, metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, aluminum or other metal or oxide thereof, halide, water Those having crystal forms of coordinated phthalocyanines such as oxides and alkoxides, and phthalocyanine dimers using oxygen atoms as bridging atoms are used. In particular, titanyl phthalocyanines (also known as oxytitanium) such as X-type, τ-type metal-free phthalocyanine, A-type (also known as β-type), B-type (also known as α-type), and D-type (also known as Y-type), which are highly sensitive crystal types Phthalocyanine), vanadyl phthalocyanine, chloroindium phthalocyanine, hydroxyindium phthalocyanine, type II chlorogallium phthalocyanine, type V hydroxygallium phthalocyanine, type G, type I μ-oxo-gallium phthalocyanine dimer, type II, etc. The [mu] -oxo-aluminum phthalocyanine dimer is preferred.

  Among these phthalocyanines, A-type (also known as β-type), B-type (also known as α-type), and powder X-ray diffraction angle 2θ (± 0.2 °) are 27.1 ° or 27.3 °. D-type (Y-type) titanyl phthalocyanine, II-type chlorogallium phthalocyanine, V-type and 28.1 ° have the strongest peaks, and 26.2 ° have peaks Hydroxygallium phthalocyanine having a clear peak at 28.1 ° and a full width at half maximum W of 25.9 ° of 0.1 ° ≦ W ≦ 0.4 °, G-type μ-oxo -Gallium phthalocyanine dimer and the like are particularly preferable.

  The phthalocyanine compound may be a single compound or several mixed or mixed crystal states. As the mixed state that can be put in the phthalocyanine compound or crystal state here, those obtained by mixing the respective constituent elements later may be used, or they may be mixed in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, and crystallization. It may be the one that caused the condition. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known. In order to generate a mixed crystal state, as described in JP-A-10-48859, two types of crystals are mixed, mechanically ground and made amorphous, and then converted into a specific crystal state by solvent treatment. The method of doing is mentioned.

When an azo pigment is used as the charge generation material, various bisazo pigments and trisazo pigments are preferably used.
When an organic pigment is used as the charge generation material, one kind may be used alone, or two or more kinds of pigments may be mixed and used. In this case, it is preferable to use a combination of two or more kinds of charge generating materials having spectral sensitivity characteristics in different spectral regions of the visible region and the near red region. Among them, a disazo pigment, a trisazo pigment and a phthalocyanine pigment are preferably used in combination. More preferred.

  The binder resin used for the charge generation layer is not particularly limited, but examples include polyvinyl butyral resin, polyvinyl formal resin, polyvinyl acetal type such as partially acetalized polyvinyl butyral resin in which a part of butyral is modified with formal, acetal, or the like. Resin, Polyarylate resin, Polycarbonate resin, Polyester resin, Modified ether type polyester resin, Phenoxy resin, Polyvinyl chloride resin, Polyvinylidene chloride resin, Polyvinyl acetate resin, Polystyrene resin, Acrylic resin, Methacrylic resin, Polyacrylamide resin, Polyamide Resin, polyvinyl pyridine resin, cellulosic resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, casein, vinyl chloride Vinyl chloride-vinyl acetate copolymer such as vinyl acetate copolymer, hydroxy-modified vinyl chloride-vinyl acetate copolymer, carboxyl-modified vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer Insulating resin such as polymer, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, styrene-alkyd resin, silicon-alkyd resin, phenol-formaldehyde resin, poly-N-vinylcarbazole, polyvinylanthracene, polyvinylperylene Organic photoconductive polymers such as Any one of these binder resins may be used alone, or two or more thereof may be mixed and used in any combination.

Specifically, the charge generation layer is prepared by, for example, preparing a coating solution by dispersing a charge generation material in a solution in which the above-described binder resin is dissolved in an organic solvent, and providing this on a conductive support (providing an undercoat layer). In some cases, it is formed by coating (on the undercoat layer).
The solvent used for preparing the coating solution is not particularly limited as long as it dissolves the binder resin. For example, saturated aliphatic solvents such as pentane, hexane, octane, and nonane, and aromatics such as toluene, xylene, and anisole. Group solvents, halogenated aromatic solvents such as chlorobenzene, dichlorobenzene, chloronaphthalene, amide solvents such as N, N-dimethylformamide, N-methyl-2-pyrrolidone, methanol, ethanol, isopropanol, n-butanol, Alcohol solvents such as benzyl alcohol, aliphatic polyhydric alcohols such as glycerin and polyethylene glycol, chain or cyclic ketone solvents such as acetone, cyclohexanone, and methyl ethyl ketone, ester systems such as methyl formate, ethyl acetate, and n-butyl acetate Solvent, methylene chloride Halogenated hydrocarbon solvents such as chloroform and 1,2-dichloroethane, linear or cyclic ether solvents such as diethyl ether, dimethoxyethane, tetrahydrofuran, 1,4-dioxane, methyl cellosolve, ethyl cellosolve, acetonitrile, dimethyl Aprotic polar solvents such as sulfoxide, sulfolane, hexamethylphosphoric triamide, n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine, triethylenediamine, triethylamine and other nitrogen-containing compounds, ligroin and other mineral oils, water, etc. Can be mentioned. Any one of these may be used alone, or two or more of these may be used in combination. In addition, when providing the above-mentioned undercoat layer, what does not melt | dissolve this undercoat layer is preferable.

  In the charge generation layer, the blending ratio (weight) of the binder resin and the charge generation material is usually 10 parts by weight or more, preferably 30 parts by weight or more, and usually 1000 parts by weight with respect to 100 parts by weight of the binder resin. The film thickness is usually 0.1 μm or more, preferably 0.15 μm or more, and usually 10 μm or less, preferably 0.6 μm or less. If the ratio of the charge generation material is too high, the stability of the coating solution may be reduced due to aggregation of the charge generation material, while if the ratio of the charge generation material is too low, the sensitivity as a photoreceptor may be decreased. There is.

As a method for dispersing the charge generation material, a known dispersion method such as a ball mill dispersion method, an attritor dispersion method, or a sand mill dispersion method can be used. At this time, it is effective to refine the particles to a particle size in the range of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.
-Charge transport layer The charge transport layer of the multilayer photoconductor contains a charge transport material and usually contains a binder resin and other components used as necessary. Specifically, such a charge transport layer is prepared by, for example, preparing a coating solution by dissolving or dispersing a charge transport material or the like and a binder resin in a solvent. In addition, in the case of a reverse lamination type photosensitive layer, it can be obtained by coating and drying on a conductive support (or on the undercoat layer when an undercoat layer is provided).

  The charge transport material is not particularly limited, and any material can be used. Examples of known charge transport materials include aromatic nitro compounds such as 2,4,7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, electron withdrawing materials such as quinone compounds such as diphenoquinone, and carbazole derivatives. , Indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, thiadiazole derivatives, heterocyclic compounds such as benzofuran derivatives, aniline derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives and multiple types of these compounds Or an electron donating substance such as a polymer having a group composed of these compounds in the main chain or side chain. Among these, carbazole derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives, and those in which a plurality of these compounds are bonded are preferable. Any one of these charge transport materials may be used alone, or two or more thereof may be used in any combination.

  The binder resin is used for securing the film strength. Examples of the binder resin for the charge transport layer include butadiene resin, styrene resin, vinyl acetate resin, vinyl chloride resin, acrylic ester resin, methacrylic ester resin, vinyl alcohol resin, ethyl vinyl ether and other vinyl compound polymers and copolymer Coalesced, polyvinyl butyral resin, polyvinyl formal resin, partially modified polyvinyl acetal, polycarbonate resin, polyester resin, polyarylate resin, polyamide resin, polyurethane resin, cellulose ester resin, phenoxy resin, silicon resin, silicon-alkyd resin, poly-N- A vinyl carbazole resin etc. are mentioned. Of these, polycarbonate resins and polyarylate resins are preferred. These binder resins can also be used after being crosslinked by heat, light or the like using an appropriate curing agent. Any one of these binder resins may be used alone, or two or more thereof may be used in any combination.

  The ratio of the binder resin and the charge transport material is such that the charge transport material is used in a ratio of 20 parts by weight or more with respect to 100 parts by weight of the binder resin. Among these, 30 parts by weight or more is preferable from the viewpoint of residual potential reduction, and 40 parts by weight or more is more preferable from the viewpoint of stability and charge mobility when repeatedly used. On the other hand, from the viewpoint of thermal stability of the photosensitive layer, the charge transport material is usually used at a ratio of 150 parts by weight or less. Among these, 110 parts by weight or less is preferable from the viewpoint of compatibility between the charge transport material and the binder resin, 80 parts by weight or less is more preferable from the viewpoint of printing durability, and 70 parts by weight or less is most preferable from the viewpoint of scratch resistance.

The thickness of the charge transport layer is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, and usually 50 μm or less, preferably 45 μm or less, from the viewpoint of long life, image stability, and high resolution. Is in the range of 30 μm or less.
<Single layer type photosensitive layer>
The single-layer type photosensitive layer is formed by using a binder resin in order to ensure film strength, in the same manner as the charge transport layer of the multilayer photoconductor, in addition to the charge generation material and the charge transport material. Specifically, a charge generation material, a charge transport material, and various binder resins are dissolved or dispersed in a solvent to prepare a coating solution, and on a conductive support (or an undercoat layer when an undercoat layer is provided). It can be obtained by coating and drying.

The types of the charge transport material and the binder resin and the use ratios thereof are the same as those described for the charge transport layer of the multilayer photoreceptor. A charge generating material is further dispersed in a charge transport medium comprising these charge transport materials and a binder resin.
As the charge generation material, the same materials as those described for the charge generation layer of the multilayer photoreceptor can be used. However, in the case of a photosensitive layer of a single-layer type photoreceptor, it is necessary to sufficiently reduce the particle size of the charge generating material. Specifically, the range is usually 1 μm or less, preferably 0.5 μm or less.

If the amount of the charge generating material dispersed in the single-layer type photosensitive layer is too small, sufficient sensitivity cannot be obtained, but if it is too large, there are adverse effects such as a decrease in chargeability and a decrease in sensitivity. It is usually used in the range of 0.5% by weight or more, preferably 1% by weight or more, and usually 50% by weight or less, preferably 20% by weight or less based on the whole layer-type photosensitive layer.
In addition, the usage ratio of the binder resin and the charge generating material in the single-layer type photosensitive layer is such that the charge generating material is usually 0.1 parts by weight or more, preferably 1 part by weight or more, based on 100 parts by weight of the binder resin. It is 30 parts by weight or less, preferably 10 parts by weight or less.

The film thickness of the single-layer type photosensitive layer is usually 5 μm or more, preferably 10 μm or more, and usually 100 μm or less, preferably 50 μm or less.
<Other functional layers>
For the purpose of improving film forming properties, flexibility, coating properties, contamination resistance, gas resistance, light resistance, etc., in both the photosensitive layer and the layers constituting the photosensitive layer, both of the multilayer type photosensitive member and the single layer type photosensitive member. Additives such as well-known antioxidants, plasticizers, ultraviolet absorbers, electron-withdrawing compounds, leveling agents, and visible light shielding agents may be included.

Further, in both the laminated type photoreceptor and the single layer type photoreceptor, the photosensitive layer formed by the above procedure may be the uppermost layer, that is, the surface layer, but another layer may be provided on the photosensitive layer and used as the surface layer. Good.
For example, a protective layer may be provided for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to discharge products generated from a charger or the like.
The protective layer is formed by containing a conductive material in an appropriate binder resin, or has a charge transporting ability such as a triphenylamine skeleton described in JP-A Nos. 9-190004 and 10-252377. A copolymer using a compound can be used.

Examples of the conductive material used for the protective layer include aromatic amino compounds such as TPD (N, N′-diphenyl-N, N′-bis- (m-tolyl) benzidine), antimony oxide, indium oxide, tin oxide, and oxide. Metal oxides such as titanium, tin oxide-antimony oxide, aluminum oxide, and zinc oxide can be used, but are not limited thereto.
As the binder resin used for the protective layer, known resins such as polyamide resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, polyvinyl ketone resin, polystyrene resin, polyacrylamide resin, and siloxane resin can be used. Also, a copolymer of the above resin and a skeleton having a charge transporting ability such as a triphenylamine skeleton as described in JP-A-9-190004 and JP-A-10-252377 can be used.

The electrical resistance of the protective layer is usually in the range of 10 9 Ω · cm to 10 14 Ω · cm. If the electric resistance is higher than the above range, the residual potential is increased, resulting in an image with much fog. On the other hand, if the electric resistance is lower than the above range, the image is blurred and the resolution is reduced. Further, the protective layer must be configured so as not to substantially prevent transmission of light irradiated during image exposure.
Further, for the purpose of reducing the frictional resistance and wear on the surface of the photoconductor, and increasing the transfer efficiency of the toner from the photoconductor to the transfer belt and paper, etc., the surface layer is made of fluorine resin, silicon resin, polyethylene resin, etc. Particles made of this resin or inorganic compound particles may be contained in the surface layer. Alternatively, a layer containing these resins and particles may be newly formed as a surface layer.
<Method for forming each layer>
The undercoat layer of the present invention and each layer constituting the photoconductor are formed by dip coating, spray coating, nozzle coating, bar coating on a support obtained by dissolving or dispersing a substance contained in each layer in a solvent. It is formed by repeating the coating / drying step for each layer in order by a known method such as coating, roll coating, blade coating or the like.

  There are no particular restrictions on the solvent or dispersion medium used in the preparation of the coating solution, but specific examples include alcohols such as methanol, ethanol, propanol and 2-methoxyethanol, tetrahydrofuran, 1,4-dioxane, dimethoxyethane and the like. Ethers, esters such as methyl formate and ethyl acetate, ketones such as acetone, methyl ethyl ketone and cyclohexanone, aromatic hydrocarbons such as benzene, toluene and xylene, dichloromethane, chloroform, 1,2-dichloroethane, 1,1, Chlorinated hydrocarbons such as 2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichloroethylene, n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine , Nitrogen-containing compounds such as triethylenediamine, acetonitrile, N- methylpyrrolidone, N, N- dimethylformamide, aprotic polar solvents such as dimethyl sulfoxide and the like. Moreover, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and kinds.

The amount of the solvent or dispersion medium used is not particularly limited, but considering the purpose of each layer and the properties of the selected solvent / dispersion medium, it is appropriate so that the physical properties such as solid content concentration and viscosity of the coating liquid are within a desired range. It is preferable to adjust.
For example, in the case of a charge transport layer layer of a single layer type photoreceptor and a function separation type photoreceptor, the solid content concentration of the coating solution is usually 5% by weight or more, usually 5% by weight or more, preferably 10% by weight or more, Moreover, it is usually 40% by weight or less, preferably 35% by weight or less. Further, the viscosity of the coating solution is usually in the range of 10 cps or more, preferably 50 cps or more, and usually 500 cps or less, preferably 400 cps or less.

In the case of a charge generating layer of a multilayer photoreceptor, the solid content concentration of the coating solution is usually 0.1% by weight or more, preferably 1% by weight or more, and usually 15% by weight or less, preferably 10% by weight. % Or less. The viscosity of the coating solution is usually 0.01 cps or more, preferably 0.1 cps or more, and usually 20 cps or less, preferably 10 cps or less.
Examples of the coating method include a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, an air knife coating method, and a curtain coating method. Other known coating methods can also be used.

The coating solution is preferably dried by touching at room temperature, followed by heating or drying in a temperature range of usually 30 ° C. or more and 200 ° C. or less for 1 minute to 2 hours, while still or blowing. The heating temperature may be constant or the heating may be performed while changing the temperature during drying.
<Image forming apparatus>
An image forming apparatus such as a copying machine or a printer using the electrophotographic photosensitive member of the present invention includes at least charging, exposure, development, transfer, and static elimination processes. Also good.

  As the charging method (charging machine), for example, in addition to corotron and scorotron charging using corona discharge, a direct charging means for charging a surface by contacting a directly charged member to which a voltage is applied may be used. As the direct charging means, any one such as contact charging using a conductive roller, brush, or film may be used, and any of those that involve air discharge or injection charging that does not involve air discharge is possible. Among these, scorotron charging is preferable in the charging method using corona discharge in order to keep the dark portion potential constant. As a charging method in the case of a contact charging device using a conductive roller or the like, DC charging or AC superimposed DC charging can be used.

  As the exposure light, halogen lamps, fluorescent lamps, lasers (semiconductors, He—Ne), LEDs, photoconductor internal exposure systems, and the like are used. As digital electrophotographic systems, lasers, LEDs, optical shutter arrays, and the like are used. preferable. As the wavelength, in addition to monochromatic light of 780 nm, monochromatic light near a short wavelength in the 600 to 700 nm region and short wavelength monochromatic light in the 380 to 500 nm region can be used.

  For the development process, a dry development method such as cascade development, one-component insulating toner development, one-component conductive toner development, two-component magnetic brush development, or the like is used. As the toner, in addition to the pulverized toner, a polymerized toner such as suspension polymerization or emulsion polymerization aggregation method can be used. In particular, in the case of the polymerized toner, those having a small particle diameter of about 4 to 8 μm in average diameter are used, and those having a shape close to a spherical shape or those outside a potato-like spherical shape can be used. The polymerized toner is excellent in charging uniformity and transferability and is suitably used for high image quality.

For the transfer step, electrostatic transfer methods such as corona transfer, roller transfer, and belt transfer, pressure transfer methods, and adhesive transfer methods are used. For fixing, heat roller fixing, flash fixing, oven fixing, pressure fixing, or the like is used.
For cleaning, brush cleaner, magnetic brush cleaner, electrostatic brush cleaner, magnetic roller cleaner, blade cleaner, etc. are used.

In many cases, the static elimination step is omitted, but when used, a fluorescent lamp, LED, or the like is used, and an exposure energy that is three times or more of the exposure light is often used as the intensity. In addition to these processes, a pre-exposure process and an auxiliary charging process may be included.
An embodiment of an image forming apparatus using the electrophotographic photosensitive member of the present invention will be described with reference to FIG. However, the embodiment is not limited to the following description, and can be arbitrarily modified without departing from the gist of the present invention.

As shown in FIG. 1, the image forming apparatus includes an electrophotographic photosensitive member 1, a charging device 2, an exposure device 3, and a developing device 4, and further, a transfer device 5, a cleaning device 6 and a fixing device as necessary. A device 7 is provided.
The electrophotographic photoreceptor 1 is not particularly limited as long as it is the above-described electrophotographic photoreceptor of the present invention, but in FIG. 1, as an example, a drum in which the above-described photosensitive layer is formed on the surface of a cylindrical conductive support. The photoconductor is shown. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are disposed along the outer peripheral surface of the electrophotographic photosensitive member 1.

The charging device 2 charges the electrophotographic photosensitive member 1 and uniformly charges the surface of the electrophotographic photosensitive member 1 to a predetermined potential. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2, but other corona charging devices such as corotron and scorotron, and contact-type charging devices such as charging brushes are often used.
In many cases, the electrophotographic photosensitive member 1 and the charging device 2 are designed to be removable from the main body of the image forming apparatus as a cartridge including both of them (hereinafter also referred to as a photosensitive cartridge). For example, when the electrophotographic photoreceptor 1 or the charging device 2 deteriorates, the photoreceptor cartridge can be removed from the image forming apparatus main body, and another new photosensitive cartridge can be mounted on the image forming apparatus main body. ing. Also, the toner described later is often stored in the toner cartridge and designed to be removable from the main body of the image forming apparatus. When the toner in the used toner cartridge runs out, this toner cartridge is removed. It can be removed from the main body of the image forming apparatus and another new toner cartridge can be mounted. Further, a cartridge equipped with all of the electrophotographic photosensitive member 1, the charging device 2, and the toner may be used.

  The type of the exposure apparatus 3 is not particularly limited as long as it can expose the electrophotographic photoreceptor 1 to form an electrostatic latent image on the photosensitive surface of the electrophotographic photoreceptor 1. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, LEDs, and the like. Further, exposure may be performed by a photoreceptor internal exposure method. The light used for the exposure is arbitrary. For example, the exposure may be performed using monochromatic light with a wavelength of 780 nm, monochromatic light with a wavelength slightly shorter than 600 nm to 700 nm, or monochromatic light with a short wavelength of 380 nm to 500 nm. .

  The type of the developing device 4 is not particularly limited, and an arbitrary device such as a dry development method such as cascade development, one-component conductive toner development, two-component magnetic brush development, or a wet development method can be used. In FIG. 1, the developing device 4 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and has a configuration in which toner T is stored inside the developing tank 41. . Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing device 4 as necessary. The replenishing device is configured to be able to replenish toner T from a container such as a bottle or a cartridge.

The supply roller 43 is formed from a conductive sponge or the like. The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicon resin, a urethane resin, a fluorine resin, or the like. The surface of the developing roller 44 may be smoothed or roughened as necessary.
The developing roller 44 is disposed between the electrophotographic photoreceptor 1 and the supply roller 43 and is in contact with the electrophotographic photoreceptor 1 and the supply roller 43, respectively. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism (not shown). The supply roller 43 carries the stored toner T and supplies it to the developing roller 44. The developing roller 44 carries the toner T supplied by the supply roller 43 and contacts the surface of the electrophotographic photosensitive member 1.

  The restricting member 45 is formed of a resin blade such as silicon resin or urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such a metal blade with resin. The regulating member 45 contacts the developing roller 44 and is pressed against the developing roller 44 side with a predetermined force by a spring or the like (a general blade linear pressure is 5 to 500 g / cm). If necessary, the regulating member 45 may be provided with a function of imparting charging to the toner T by frictional charging with the toner T.

The agitator 42 is rotated by a rotation driving mechanism, and agitates the toner T and conveys the toner T to the supply roller 43 side. A plurality of agitators 42 may be provided with different blade shapes and sizes.
The type of the toner T is arbitrary, and in addition to the powdery toner, a polymerized toner using a suspension polymerization method, an emulsion polymerization method, or the like can be used. In particular, when a polymerized toner is used, a toner having a small particle diameter of about 4 to 8 μm is preferable, and the toner particles are used in various shapes ranging from a nearly spherical shape to a shape outside the spherical shape on the potato. be able to. The polymerized toner is excellent in charging uniformity and transferability and is suitably used for high image quality.

  The type of the transfer device 5 is not particularly limited, and an apparatus using an arbitrary system such as an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, or an adhesive transfer method can be used. . Here, it is assumed that the transfer device 5 includes a transfer charger, a transfer roller, a transfer belt, and the like that are disposed to face the electrophotographic photoreceptor 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner T, and transfers the toner image formed on the electrophotographic photosensitive member 1 to a recording paper (paper, medium) P. Is.

There is no restriction | limiting in particular about the cleaning apparatus 6, Arbitrary cleaning apparatuses, such as a brush cleaner, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, can be used. The cleaning device 6 is for scraping off residual toner adhering to the photoreceptor 1 with a cleaning member and collecting the residual toner. If there is little or almost no residual toner, the cleaning device 6 may be omitted.
The fixing device 7 includes an upper fixing member (fixing roller) 71 and a lower fixing member (fixing roller) 72, and a heating device 73 is provided inside the fixing member 71 or 72. FIG. 1 shows an example in which a heating device 73 is provided inside the upper fixing member 71. Each of the upper and lower fixing members 71 and 72 includes a fixing roll in which a metal base tube such as stainless steel or aluminum is coated with silicon rubber, a fixing roll in which Teflon (registered trademark) resin is coated, and a fixing sheet. A member can be used. Further, each of the fixing members 71 and 72 may be configured to supply a release agent such as silicon oil in order to improve releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

When the toner transferred onto the recording paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P.
The type of the fixing device is not particularly limited, and a fixing device of any type such as heat roller fixing, flash fixing, oven fixing, pressure fixing, etc. can be provided including those used here.

In the electrophotographic apparatus configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the photoreceptor 1 is charged to a predetermined potential (for example, −600 V) by the charging device 2. At this time, charging may be performed by a DC voltage, or charging may be performed by superimposing an AC voltage on the DC voltage.
Subsequently, the photosensitive surface of the charged photoreceptor 1 is exposed by the exposure device 3 according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. The developing device 4 develops the electrostatic latent image formed on the photosensitive surface of the photoreceptor 1.

The developing device 4 thins the toner T supplied by the supply roller 43 with a regulating member (developing blade) 45 and has a predetermined polarity (here, the same polarity as the charging potential of the photosensitive member 1) and the negative polarity. ), And conveyed while being carried on the developing roller 44 to be brought into contact with the surface of the photoreceptor 1.
When the charged toner T carried on the developing roller 44 comes into contact with the surface of the photoreceptor 1, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the photoreceptor 1. This toner image is transferred onto the recording paper P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the photoreceptor 1 without being transferred is removed by the cleaning device 6.

After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the fixing device 7 and thermally fixing the toner image onto the recording paper P.
In addition to the above-described configuration, the image forming apparatus may be configured to perform, for example, a static elimination process. The neutralization step is a step of neutralizing the electrophotographic photosensitive member by exposing the electrophotographic photosensitive member, and a fluorescent lamp, an LED, or the like is used as the neutralizing device. In addition, the light used in the static elimination process is often light having an exposure energy that is at least three times that of the exposure light.

  The image forming apparatus may be further modified. For example, the image forming apparatus may be configured to perform a pre-exposure process, an auxiliary charging process, or the like, or may be configured to perform offset printing. A full-color tandem system configuration using toner may be used.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention still in detail, this invention is not limited to these, unless the summary is exceeded. In the examples, “parts” means “parts by weight” unless otherwise specified.
<Manufacture of dispersion for undercoat layer coating formation>
・ Dispersion P1
Γ-mercaptopropyltrimethoxysilane (product name: TSL8380, manufactured by Toshiba Silicone) with respect to rutile-type white titanium oxide having an average primary particle size of 40 nm (product name: TTO55N, manufactured by Ishihara Sangyo Co., Ltd.) and 100 parts of the titanium oxide. The slurry obtained by mixing the parts with a ball mill was fired at 120 ° C. for 1 hour to prepare surface-treated titanium oxide. Next, this surface-treated titanium oxide is subjected to ball mill dispersion in a mixed solvent of methanol / 1-propanol = 7/3, and a γ-mercaptopropyltrimethoxysilane-treated titanium oxide dispersion having a solid content concentration of 33.3% by weight is obtained. Obtained.

  The titanium oxide dispersion obtained here was mixed alcohol (methanol / 1-propanol) of a random copolymerized polyamide of the following structural formula (3) produced by the production method described in the example of JP-A-4-31870. = 70/30) The resulting mixture was mixed with a solution to finally prepare a dispersion having a solid content concentration of 16% by weight with a titanium oxide / nylon ratio of 3/1 (weight ratio), and this was designated as dispersion (P1).

・ Dispersion P2
Dispersion P2 was prepared in the same manner as dispersion P1, except that the amount of γ-mercaptopropyltrimethoxysilane used in the preparation of dispersion P1 was 10 parts.
・ Dispersion P3
A dispersion P3 was prepared in the same manner as the dispersion P1, except that 5 parts of methyldimethoxysilane was used instead of the γ-mercaptopropyltrimethoxysilane-treated titanium oxide used in the preparation of the dispersion P1.
・ Dispersion P4
Dispersion P4 was prepared in the same manner as Dispersion P1, except that 10 parts of methyldimethoxysilane was used instead of the γ-mercaptopropyltrimethoxysilane-treated titanium oxide used in the preparation of Dispersion P1.
・ Dispersion P5
Dispersion P5 was prepared in the same manner as dispersion P1, except that titanium oxide not subjected to surface treatment was used.
Example 1
The undercoat layer is obtained by dip-coating the dispersion P1 on an aluminum cylinder having a mirror-finished outer diameter of 30 mm, length of 254 mm, and wall thickness of 1.0 mm so that the dry film thickness is 0.75 μm. Was provided.

  Next, the powder X-ray diffraction spectrum by CuKα characteristic X-ray has a Bragg angle 2θ ± 0.2 and has strong peaks at 10.5 °, 26.2 °, and 27.2 °. 1 part, 500 parts of 1,2-dimethoxyethane was added to 5 parts of polyvinyl butyral (trade name # 6000-C, manufactured by Denki Kagaku Kogyo Co., Ltd.), and pulverized and dispersed by a sand grind mill. This dispersion was dip-coated on the previously provided undercoat layer, and a charge generation layer was provided so that the dry film thickness was about 0.3 μm.

  Next, 56 parts by weight of hydrazone compound A shown below, 14 parts by weight of hydrazone compound B, 1.5 parts by weight of cyanide compound shown below, and the production method described in the examples of JP-A-3-221196 A coating solution prepared by dissolving 100 parts of the polycarbonate resin shown below having two repeating structural units thus prepared in 620 parts by weight of a mixed solvent of 1,4 dioxane: tetrahydrofuran = 65: 25 is placed on the charge generation layer. By dip coating, a charge transport layer was provided so that the dry film thickness was 17 μm. The photoreceptor thus obtained is designated as photoreceptor A1.

Example 2
A photoconductor A2 was produced in the same manner as in Example 1 except that the dispersion P2 was used instead of the dispersion P1 used for forming the undercoat layer of Example 1.
Comparative Example 1
A comparative photoreceptor A3 was produced in the same manner as in Example 1 except that the dispersion P3 was used instead of the dispersion P1 used for forming the undercoat layer of Example 1.
Comparative Example 2
A comparative photoreceptor A4 was produced in the same manner as in Example 1 except that the dispersion P4 was used instead of the dispersion P1 used for forming the undercoat layer of Example 1.
Comparative Example 3
A comparative photoreceptor A5 was produced in the same manner as in Example 1 except that the dispersion P5 was used instead of the dispersion P1 used for forming the undercoat layer of Example 1.
Example 3
A photosensitive drum was obtained in the same manner as in Example 1 except that the undercoat layer was provided so that the dry film thickness of the undercoat layer was 1.25 μm. The photoreceptor thus obtained is designated as photoreceptor B1.
Example 4
Example 1 except that the dispersion P2 was dip-coated instead of the dispersion P1 used to form the undercoat layer of Example 1 and the undercoat layer was provided so that the dry film thickness was 1.25 μm. In the same manner as above, a photosensitive drum was obtained. The photoreceptor thus obtained is designated as photoreceptor B2.
Comparative Example 4
Example 2 except that the dispersion P3 was dip-coated instead of the dispersion P2 used for forming the undercoat layer of Example 2 and the undercoat layer was provided so that the dry film thickness was 1.25 μm. In the same manner as above, a photosensitive drum was obtained. The photoreceptor thus obtained is referred to as a comparative photoreceptor B3.
Comparative Example 5
Photosensitive drum in the same manner as in Example 1 except that the aluminum cylinder used in Example 1 was dip-coated in dispersion P4 and an undercoat layer was provided so that the dry film thickness was 1.25 μm. Got. The photoreceptor thus obtained is referred to as a comparative photoreceptor B4.
Comparative Example 6
A photosensitive drum was obtained in the same manner as in Example 1 except that the aluminum cylinder used in Example 1 was dip-coated in dispersion P5 and a pulling layer was provided so that the dry film thickness was 1.25 μm. It was. The photoreceptor thus obtained is referred to as a comparative photoreceptor B5.
Comparative Example 7
A photosensitive drum was obtained in the same manner as in Example 1 except that the undercoat layer was not provided. This photoreceptor is referred to as a comparative photoreceptor C1.
[Evaluation of Photosensitive Drum]
The photoreceptors manufactured in Examples 1 to 4 and Comparative Examples 1 to 7 were mounted on a commercially available laser printer (LASER JET 4 PLUS manufactured by HEWLETT PACKARD) to form a white background image in various environments, and image evaluation was performed. went. For image evaluation, spectro color meter SE2000 (NIPPON DENSHOKU) was used, and the whiteness of the paper before image printing (5 points per sheet were measured and the average value was obtained as data) was measured. The whiteness of the paper after the image formation was measured in the same manner as the whiteness of the paper before the image was printed, and the whiteness before the image formation was determined from the whiteness value after the image formation. The difference in the degree value was calculated as whiteness. The results are shown in Table 1.

  The photoreceptors of Examples 1 to 4 (photoreceptors A1, A2, B1, and B2) and the photoreceptors of Comparative Examples 1, 2, 4, and 5 (comparative photoreceptors A3, A4, B3, and B4) have a temperature / relative relationship. Humidity: 5 ° C / 10% (hereinafter sometimes referred to as LL environment), 25 ° C / 50% (hereinafter also referred to as NN environment), 35 ° C / 85% (hereinafter sometimes referred to as HH environment) A good image was obtained in any of the above environments, but the whiteness values of the photoconductors of Comparative Examples 3, 6, and 7 (Comparative Photoconductors A5, B5, and C1) were high, and the actual image was visually confirmed. Even fog was observed.

  Next, the electrophotographic photoreceptors of Examples 1 to 4 and Comparative Examples 1 to 7 were used as photoreceptor characteristic measuring machines (basic and applied electrophotographic techniques, edited by Electrophotographic Society, Corona, pages 404 to 405). And charged to a surface potential of −700 V, and then half-exposure when irradiated with light of 780 nm (hereinafter sometimes referred to as sensitivity), further charged to −700 V and 5 The potential holding ratio after 2 seconds and the residual potential after removing the 660 nm LED light were measured. The smaller the values of sensitivity and residual potential, the higher the performance of the electrophotographic photoreceptor. The results are shown in Table 2.

  The photoconductors A1, A2, B1, and B2 of the present invention are particularly excellent in sensitivity in all environments, and in the photoconductor having an undercoat layer, the residual potential is also excellent in all environments.

1 is a conceptual diagram illustrating an embodiment of an image forming apparatus using an electrophotographic photosensitive member of the present invention.

Explanation of symbols

1 Photoconductor 2 Charging device (charging roller)
DESCRIPTION OF SYMBOLS 3 Exposure apparatus 4 Developing apparatus 5 Transfer apparatus 6 Cleaning apparatus 7 Fixing apparatus 41 Developing tank 42 Agitator 43 Supply roller 44 Developing roller 45 Control member 71 Upper fixing member (fixing roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper

Claims (7)

An electrophotographic photosensitive member having an undercoat layer and a photosensitive layer on a conductive substrate, wherein the undercoat layer contains metal compound particles having an organic group containing a sulfur atom, and a binder resin. Photoconductor. The electrophotographic photosensitive member according to claim 1, wherein the metal compound particles having an organic group containing a sulfur atom have an organosilicon group. The electrophotographic photoreceptor according to claim 1, wherein the organic group containing a sulfur atom is a mercapto group. The electrophotographic photosensitive member according to claim 1, wherein the metal compound particles are titanium oxide particles. The electrophotographic photosensitive member according to claim 1, wherein the binder resin is a polyamide resin. An image forming apparatus using the electrophotographic photosensitive member according to claim 1. A cartridge for an image forming apparatus using the electrophotographic photosensitive member according to claim 1.

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