JP5353078B2 - Electrophotographic photosensitive member and image forming apparatus using compound having enamine skeleton - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor containing in a photosensitive layer a compound suitable for use in a photosensitive layer of an electrophotographic photoreceptor and having good solubility, high charge mobility and excellent electrical characteristics, and also to provide an image-forming apparatus using the photoreceptor. <P>SOLUTION: The electrophotographic photoreceptor has the photosensitive layer on a conductive support, wherein the photosensitive layer contains at least one enamine compound represented by a general formula [I]. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to an electrophotographic photoreceptor and an image forming apparatus having a photosensitive layer containing a compound having an arylamine skeleton that can be suitably used as a photoconductive material for an electrophotographic photoreceptor.

  The electrophotographic technique is widely used in the fields of copiers, various printers, printing machines, etc. because it is excellent in immediacy and provides high-quality images. As an electrophotographic photoreceptor that is the core of electrophotographic technology, an electrophotographic photoreceptor using an organic photoconductive material (hereinafter simply referred to as “photosensitive material”) that has advantages such as non-pollution, easy film formation, and easy manufacture. Also referred to as "body").

  As an electrophotographic photoreceptor using an organic photoconductive material, a so-called dispersion type single-layer photoreceptor in which a photoconductive fine powder is dispersed in a binder resin, a charge generation layer and a charge transport layer are laminated. A laminated type photoconductor is known. Multilayer photoconductors can be obtained by combining highly efficient charge generation materials and charge transport materials in separate layers, and combining them with high sensitivity and stability. Photoconductors that are easy to adjust are obtained, and the photosensitive layer can be easily formed by coating, has high productivity, and is advantageous in terms of cost. Yes.

  On the other hand, the single-layer type photoconductor is slightly inferior to the multilayer type photoconductor in terms of electrical characteristics and the degree of freedom of material selection is somewhat small, but it can generate charges near the surface of the photoconductor, so it has high resolution. In addition, there is an advantage that a high printing durability can be achieved by increasing the thickness of the film because the image is not blurred even if the thickness is increased. In addition, the single-layer type photoreceptor is advantageous in that the coating process is small, and it is advantageous for interference fringes and tube defects derived from the conductive support, and an inexpensive substrate such as a non-cutting tube can be used. Therefore, there is an advantage that the cost can be reduced.

  Further, since the electrophotographic photosensitive member is repeatedly used in an electrophotographic process, that is, a cycle such as charging, exposure, development, transfer, cleaning, and static elimination, it is deteriorated by various stresses during that time. Among these, as chemical deterioration, for example, strong oxidizing ozone or NOx generated from a corona charger usually used as a charger may damage the photosensitive layer. Deterioration in electrical stability such as a decrease or increase in residual potential, and accompanying image defects may occur. These are largely derived from chemical deterioration of charge transport materials contained in the photosensitive layer in a large amount.

  Furthermore, with the recent speeding up of the electrophotographic process, it is essential to increase the sensitivity and speed of the electrophotographic photosensitive member. Of these, in order to achieve high sensitivity, it is necessary not only to optimize charge generation materials, but also to develop charge transport materials with good matching with them. There is a need to develop charge transport materials that exhibit sensitivity and a sufficiently low residual potential upon exposure.

  As a conventional technique, it is known that an enamine compound can be used as a photoconductive material for an electrophotographic photoreceptor. For example, it has been proposed that the enamine compounds described in Patent Documents 1 and 2 can be used as charge transport materials. Such a group of compounds had relatively low mobility, and there was a point that should improve electric characteristics. Further, since there are difficulties in the solubility in a solvent and the stability of the coating solution at the time of production of the photoconductor, the actual situation is not yet satisfied in the photoconductor market.

As a result of diligent studies to improve the above problems, the present inventors have introduced a substituent into an aryl group directly connected to a nitrogen atom of a compound having an arylamine skeleton, thereby improving photosensitivity, residual potential, and charge transfer. It has been found that the properties such as the temperature can be remarkably improved, and the solubility in a solvent at the time of production of the photoreceptor can be greatly improved. In addition, when such a compound is used in the photosensitive layer of an electrophotographic photoreceptor, it has been found that it exhibits excellent characteristics such as photosensitivity, residual potential, charge mobility, potential stability during durability, and environmental stability. It was.
Japanese Patent Laid-Open No. 7-146574 Japanese Patent Publication No. 2653080

  The present invention has been made in view of the present situation, and its purpose is to have good solubility, high charge mobility, which can be suitably used for a photosensitive layer of an electrophotographic photosensitive member, and An object of the present invention is to provide an electrophotographic photoreceptor containing a compound having excellent electrical characteristics in a photosensitive layer, and an image forming apparatus using the photoreceptor.

  By introducing a substituent into the aryl group directly connected to the nitrogen atom of the compound having an arylamine skeleton, the present inventors have remarkably improved characteristics such as photosensitivity, residual potential, and charge mobility. It has been found that the solubility in a solvent at the time of production is also greatly improved. In addition, when such a compound is used in the photosensitive layer of an electrophotographic photoreceptor, it has been found that it exhibits excellent characteristics such as photosensitivity, residual potential, charge mobility, potential stability during durability, and environmental stability. The present invention has been completed.

  The first present invention is an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer contains at least one enamine compound represented by the general formula [I]. And an electrophotographic photosensitive member.

（式［Ｉ］中、Ａｒ^１〜Ａｒ^６は、同一または異なっていてもよく、それぞれ置換基を有していてもよいアリール基を表し、ｎは２以上の整数を表し、Ｚは一価の有機残基を表し、ｍは０〜４の整数を表す。ただし、Ａｒ^１〜Ａｒ^２のうち、少なくとも一つは、置換基を有するアリール基である。）。

(In Formula [I], Ar ^{1 to} Ar ⁶ may be the same or different and each represents an aryl group which may have a substituent, n represents an integer of 2 or more, and Z represents a monovalent group. M represents an integer of 0 to 4, provided that at least one of Ar ^{1 to} Ar ² is an aryl group having a substituent.

  The second aspect of the present invention is an electrophotographic photosensitive member according to the first aspect of the present invention, a charging unit that charges the electrophotographic photosensitive member, an exposure unit that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image, And an image forming apparatus including a developing unit that develops the electrostatic latent image formed on the electrophotographic photosensitive member by exposure using toner.

  The compound according to the present invention has excellent solubility, high charge mobility, and excellent electrical characteristics. Therefore, when it is included in the photosensitive layer of an electrophotographic photoreceptor, the electrophotographic photoreceptor is repeatedly used. Even in this case, it is possible to provide an electrophotographic photosensitive member that has good electrical characteristics stability, quick response, high sensitivity, and low residual potential, and an image forming apparatus including the same.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention will be described in detail. However, the present invention is not limited to the following embodiment, and various modifications can be made within the scope of the present invention. it can.
The electrophotographic photoreceptor of the present invention has a photosensitive layer on a conductive support, and the photosensitive layer contains a compound represented by the following formula [I].

（式［Ｉ］中、Ａｒ^１〜Ａｒ^６は、同一または異なっていてもよく、それぞれ置換基を有していてもよいアリール基を表し、ｎは２以上の整数を表し、Ｚは一価の有機残基を表し、ｍは０〜４の整数を表す。ただし、Ａｒ^１〜Ａｒ^２のうち、少なくとも一つは、置換基を有するアリール基である。）

(In Formula [I], Ar ^{1 to} Ar ⁶ may be the same or different and each represents an aryl group which may have a substituent, n represents an integer of 2 or more, and Z represents a monovalent group. And m represents an integer of 0 to 4. However, at least one of Ar ^{1 to} Ar ² is an aryl group having a substituent.)

In the formula [I], Ar ^{1 to} Ar ⁶ represent aryl groups which may have a substituent, and may be the same or different. Among them, an aryl group having 6 to 20 carbon atoms is preferable, and an aryl group having 6 to 12 carbon atoms is more preferable. Specific examples include a phenyl group, a naphthyl group, a fluorenyl group, an anthryl group, a phenanthryl group, and a pyrenyl group, and a phenyl group, a naphthyl group, and a fluorenyl group are preferable. From the viewpoint of production cost, an aryl group having 6 to 10 carbon atoms such as a phenyl group and a naphthyl group is particularly preferable. Further, when it has a substituent, the substituent is preferably a substituent having 1 to 10 carbon atoms and having a substituent constant σp of 0.20 or less according to Hammett's rule.

  Here, Hammett's rule is an empirical rule used to explain the effect of a substituent in an aromatic compound on the electronic state of an aromatic ring, and the substituent constant σp of the substituted benzene is the electron donation / It can be said that this is a value obtained by quantifying the degree of suction. If the σp value is positive, the substituted benzoic acid is more acidic than the unsubstituted one, that is, an electron-withdrawing substituent. Conversely, when the σp value is negative, an electron donating substituent is formed. Table 1 shows σp values of representative substituents (The Chemical Society of Japan, “Chemical Handbook, Basic Edition II, 4th revised edition”, Maruzen Co., Ltd., published on September 30, 1993, p.364-365). .

  Examples of such a substituent include an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylamino group having 2 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and the like. Specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, methoxy group, ethoxy group, propoxy group, butoxy group, N, N-dimethylamino group N, N-diethylamino group, phenyl group, 4-tolyl group, 4-ethylphenyl group, 4-propylphenyl group, 4-butylphenyl group, naphthyl group and the like. Among these, from the viewpoint of electrical characteristics, an alkyl group having 1 to 4 carbon atoms is preferable, and a methyl group and an ethyl group are particularly preferable.

  In the formula [I], n is an integer of usually 2 or more in terms of improving the electrical characteristics of the electrophotographic photoreceptor according to the present invention, and there is no particular upper limit as long as the electrical characteristics are not adversely affected. An integer of 5 or less is preferable, and an integer of 3 or less is more preferable. From the viewpoint of compatibility with the photosensitive layer and production cost, n is preferably 2 or 3, particularly preferably n = 2.

In the formula [I], examples of the monovalent organic residue Z include, for example, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkylamino group having 2 to 4 carbon atoms, and 6 carbon atoms. -10 aryl groups and the like, specifically, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, butoxy, N, N-dimethylamino, N, N-diethylamino, phenyl, 4-tolyl, 4-ethylphenyl, 4-propylphenyl, 4-butylphenyl, naphthyl and the like can be mentioned. Among these, an alkyl group having 1 to 4 carbon atoms is particularly preferable from the viewpoint of electrical characteristics.
In the general formula [1], m is preferably an integer of 0 to 1, but is preferably m = 0 from the viewpoint of production cost.

  As typical examples of the compound represented by the formula [I], the following exemplified compounds CT-1 to CT-14 may be mentioned. However, the compound represented by the formula [I] according to the present invention is not limited to these compounds.

  These compounds can be easily synthesized by known methods. For example, exemplary compound CT-1 of this invention can be manufactured according to the following reaction formula.

  The diarylamine derivative (α) is condensed by reflux dehydration with diarylacetaldehyde (β) in the presence of an acid catalyst such as p-toluenesulfonic acid to obtain the target charge transport material (CT-1). be able to.

  The structure of the electrophotographic photosensitive member according to the present invention will be described below. The structure of the electrophotographic photosensitive member according to the present invention is not particularly limited as long as the photosensitive layer containing the compound represented by the formula [I] described above is provided on a conductive support. A layered photoreceptor in which a generation layer and a charge transport layer are stacked is preferable, and it is particularly preferable that the charge transport layer contains the compound.

<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 conductive support may be smooth, or may be roughened by using a special cutting method or performing a polishing treatment. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the conductive support. In order to reduce the cost, it is possible to use the drawing tube as it is without performing the cutting process.

<Underlayer>
An undercoat layer may be provided between the conductive support and the photosensitive layer described later for improving adhesion and blocking properties. As the undercoat layer, a resin, a resin in which particles such as a metal oxide are dispersed, or the like is used.
Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. One kind of these particles may be used alone, or a plurality of kinds of particles may be mixed and used. Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicon. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. Moreover, the thing of a several crystal state may be contained.

  Various particle diameters of the metal oxide particles can be used. Among these, from the viewpoint of characteristics and liquid stability, the average primary particle diameter is preferably 10 nm or more and 100 nm or less, and particularly preferably 10 nm or more and 50 nm. It is as follows.

  The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. The binder resin used for the undercoat layer is epoxy resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, polyimide resin, chloride Cellulose esters such as vinylidene resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, polyurethane resin, polyacryl resin, polyacrylamide resin, polyvinyl pyrrolidone resin, polyvinyl pyridine resin, water-soluble polyester resin, nitrocellulose Resin, cellulose ether resin, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, zirconium chelate compound, zirconium Rukokishido compounds such as organic zirconium compounds of titanyl chelate compounds, organic titanyl compounds such as titanium alkoxide compounds include known binder resins, such as silane coupling agent. These may be used alone or in combination of two or more in any combination and ratio. Moreover, you may use with the hardening | curing form with the hardening | curing agent. Among these, alcohol-soluble copolymerized polyamides, modified polyamides, and the like are preferable because they exhibit good dispersibility and coatability.

The use ratio of the inorganic particles to the binder resin used in the undercoat layer can be arbitrarily selected, but is usually in the range of 10% by mass or more and 500% by mass or less from the viewpoint of the stability of the dispersion and the coating property. Is preferably used.
The thickness of the undercoat layer can be selected arbitrarily, but is usually preferably in the range of 0.1 μm or more and 20 μm or less from the viewpoint of improving the photoreceptor characteristics and applicability.
A known antioxidant or the like may be mixed in the undercoat layer. For the purpose of preventing image defects, pigment particles, resin particles and the like may be contained and used.

<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-generating layer and a charge transport layer are laminated in this order from the conductive support side, and conversely, a charge transport layer and a charge generation layer are formed from the conductive support side. There are reverse laminated photosensitive layers provided in order, and any of them can be adopted, but a forward laminated photosensitive layer that can exhibit 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 generation material, 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, white light, laser light having a wavelength around 660 nm, or relatively short wavelength laser light (for example, laser light having a wavelength in the range of 380 to 500 nm) Thus, a photoreceptor having sufficient 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 highly sensitive photoreceptor with respect to a relatively long wavelength laser beam, and the azo pigment includes white light and a relatively short wavelength laser beam (for example, a wavelength in the range of 380 to 500 nm). Each of them is excellent in that it has sufficient sensitivity to a laser beam.

  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, chlorogallium phthalocyanine such as type II, hydroxygallium phthalocyanine such as type V, μ-oxo-gallium phthalocyanine dimer such as type G and type I, 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, type II chlorogallium phthalocyanine, which has a clear peak at 28.1 °, and no peak at 26.2 ° V-type hydroxygallium phthalocyanine, G-type μ-oxo, having a clear peak at 1 ° and a half-width W of 25.9 ° of 0.1 ° ≦ W ≦ 0.4 ° -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 in the phthalocyanine compound or crystal state here, those obtained by mixing the respective constituent elements later may be used, or the mixed state in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, crystallization, etc. It may be the one that gave rise to. 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. Examples of preferred azo pigments are shown below.

  When the organic pigments exemplified above are 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 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, cellulose resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, casein, vinyl chloride -Vinyl acetate-vinyl acetate copolymers such as vinyl acetate copolymers, hydroxy-modified vinyl chloride-vinyl acetate copolymers, carboxyl-modified vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymers, etc. Insulating resins such as polymers, styrene-butadiene copolymers, vinylidene chloride-acrylonitrile copolymers, styrene-alkyd resins, silicone-alkyd resins, phenol-formaldehyde resins, poly-N-vinylcarbazole, polyvinylanthracene, polyvinyl And organic photoconductive polymers such as perylene. 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 dispersing the halogen-substituted indium phthalocyanine of the present invention and other charge generation materials used in some cases in a solution obtained by dissolving the above binder resin in an organic solvent. Is applied on a conductive support (or an undercoat layer when an undercoat layer is provided).

  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 dimethylformamide, N-methyl-2-pyrrolidone, methanol, ethanol, isopropanol, n-butanol, benzyl alcohol, etc. Alcohol solvents, aliphatic polyhydric alcohols such as glycerin and polyethylene glycol, chain or cyclic ketone solvents such as acetone, cyclohexanone, methyl ethyl ketone, 4-methoxy-4-methyl-2-pentanone, methyl formate, ethyl acetate, N-butyl acetate Ester solvents such as methylene chloride, chloroform, 1,2-dichloroethane and other halogenated hydrocarbon solvents, diethyl ether, dimethoxyethane, tetrahydrofuran, 1,4-dioxane, methyl cellosolve, ethyl cellosolve, etc. Or a cyclic ether solvent, aprotic polar solvent such as acetonitrile, dimethyl sulfoxide, sulfolane, hexamethyl phosphate triamide, nitrogen-containing compounds such as n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine, triethylenediamine, triethylamine , Mineral oil such as ligroin, water and the like. 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 (mass) of the binder resin and the charge generation material is usually 10 parts by mass or more, preferably 30 parts by mass or more, and usually 1000 parts by mass with respect to 100 parts by mass of the binder resin. Part or less, preferably 500 parts by mass or less, and 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).

  As the charge transport material, it is preferable to use a compound represented by the formula [I] according to the present invention. As the compound represented by the formula [I] according to the present invention, one type may be used alone, or a plurality of types may be used in any combination and ratio.

  In addition to the compound represented by the formula [I] according to the present invention, other known charge transport materials may be used in combination. When other charge transport materials are used in combination, the kind thereof is not particularly limited. For example, carbazole derivatives, hydrazone compounds, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, and those obtained by bonding a plurality of these derivatives are preferable. More specifically, compounds described in JP-A-2-230255, JP-A-63-225660, JP-A-58-198043, JP-B-58-32372, and JP-B-7-21646 Are preferably used. Any one of these charge transport materials may be used alone, or a plurality of types may be used in any combination. When the compound represented by the formula [I] according to the present invention is used in combination with another known charge transport material, the content ratio (% by mass) of the charge transport material to be used in the total amount of the charge transport material is: Although not particularly limited, it is preferably 50% or less, and more preferably in the range of 1 to 20%. In order to more significantly fulfill the role of the compound according to the present invention, it is particularly preferably within the range of 3 to 10%.

  Examples of the binder resin used for binding the charge transport layer include vinyl compounds such as butadiene resin, styrene resin, vinyl acetate resin, vinyl chloride resin, acrylic ester resin, methacrylic ester resin, vinyl alcohol resin, and ethyl vinyl ether. Polymers and copolymers, 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, silicone resin, silicone-alkyd Resin, poly-N-vinylcarbazole resin and the like. 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 to the charge transport material is such that the charge transport material is used in a ratio of 20 parts by mass or more with respect to 100 parts by mass of the binder resin. Among these, 30 parts by mass or more is preferable from the viewpoint of residual potential reduction, and 40 parts by mass 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 mass or less. Among these, 110 parts by mass or less is preferable from the viewpoint of compatibility between the charge transport material and the binder resin, 80 parts by mass or less is more preferable from the viewpoint of printing durability, and 70 parts by mass 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 used in the range of usually 0.5% by mass or more, preferably 1% by mass or more, and usually 50% by mass or less, preferably 20% by mass or less based on the whole layer-type photosensitive layer.

The use ratio of the binder resin to the charge generating substance in the single-layer type photosensitive layer is such that the charge generating substance is usually 0.1 parts by mass or more, preferably 1 part by mass or more, and usually 100 parts by mass of the binder resin. It is 30 mass parts or less, Preferably it is set as the range of 10 mass parts 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 a suitable binder resin, or a copolymer using a compound having a charge transporting ability such as a triphenylamine skeleton described in JP-A-9-190004. 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 described in JP-A-9-190004 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.
In addition, for the purpose of reducing the frictional resistance and wear on the surface of the photosensitive member, and increasing the transfer efficiency of the toner from the photosensitive member to the transfer belt, paper, etc., fluorine resin, silicone resin, polyethylene resin, etc. The surface layer may contain particles or inorganic compound particles. Alternatively, a layer containing these resins and particles may be newly formed as a surface layer.

<Method for forming each layer>
Each layer constituting these photoreceptors is formed by immersing, spraying, nozzle coating, bar coating, roll coating, blade coating on a conductive support obtained by dissolving or dispersing a substance to be contained in a solvent. It is formed by repeating a coating / drying step sequentially for each layer by a known method such as coating.

  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, acetone, methyl ethyl ketone, cyclohexanone, ketones such as 4-methoxy-4-methyl-2-pentanone, aromatic hydrocarbons such as benzene, toluene, xylene, dichloromethane, Chlorinated hydrocarbons such as chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichloroethylene, n-butylamine, isopropanolamine, Diethyla Emissions, 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.

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 of a single layer type photoreceptor or a function separation type photoreceptor, the solid content concentration of the coating solution is usually 5% by mass or more, preferably 10% by mass or more, and usually 40% by mass or less. The range is preferably 35% by mass or less. In addition, the viscosity of the coating solution is usually 10 mPa · s or higher, preferably 50 mPa · s or higher, and usually 500 mPa · s or lower, preferably 400 mPa · s or lower, at the temperature during use.

  In the case of a charge generation layer of a multilayer photoreceptor, the solid content concentration of the coating solution is usually 0.1% by mass or more, preferably 1% by mass or more, and usually 15% by mass or less, preferably 10% by mass. % Or less. In addition, the viscosity of the coating solution is usually 0.01 mPa · s or higher, preferably 0.1 mPa · s or higher, and usually 20 mPa · s or lower, preferably 10 mPa · s or lower, at the temperature during use.

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. Further, the heating temperature may be constant, or heating may be performed while changing the temperature during drying.

<Image forming apparatus>
Next, an embodiment of an image forming apparatus using the electrophotographic photosensitive member of the present invention (an image forming apparatus 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 arranged along the outer peripheral surface of the electrophotographic photoreceptor 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. As the charging device, a corona charging device such as corotron or scorotron, a direct charging device (contact type charging device) in which a direct charging member to which voltage is applied is brought into contact with the surface of the photosensitive member and charged is often used. Examples of the direct charging device include a charging roller and a charging brush. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2. As the direct charging means, either charging with air discharge or injection charging without air discharge is possible. Moreover, as a voltage applied at the time of charging, it is possible to use only a direct current voltage or to superimpose an alternating current on a direct current.

  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 having a wavelength of 780 nm, monochromatic light having a wavelength of 600 nm to 700 nm, slightly short wavelength, or monochromatic light having a 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 insulating toner development, one-component conductive toner development, or two-component magnetic brush development, or a wet development method is used. be able to. 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 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 silicone 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 regulating member 45 is formed of a resin blade such as silicone resin or urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such metal blade with resin. The regulating member 45 abuts on the developing roller 44 and is pressed against the developing roller 44 side with a predetermined force by a spring or the like (general blade linear pressure is 5 g / cm 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 besides the pulverized toner, a polymerized toner using a suspension polymerization method, an emulsion polymerization method, or the like can be used. In particular, a polymerized toner is preferable, and a toner having a small particle diameter of about 3 μm to 8 μm is particularly preferable. Also, the toner particles can be used in a variety of shapes, from a nearly spherical shape to a toner particle that is out of the potato shape. In particular, from the viewpoint of charging uniformity, transferability, and cleaning properties, it is preferable to use a polymerized toner produced by an emulsion polymerization aggregation method.

  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 disposed so as 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. However, when there is little or almost no toner remaining on the surface of the photoreceptor, 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. The upper and lower fixing members 71 and 72 are known heat fixings such as a fixing roll in which a metal base tube such as stainless steel or aluminum is coated with silicone rubber, a fixing roll in which Teflon (registered trademark) resin is coated, or 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 silicone 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 exposure light.
Further, the image forming apparatus may be further modified and configured, for example, a configuration capable of performing processes such as a pre-exposure process and an auxiliary charging process, a structure performing offset printing, and a plurality of types. A full-color tandem system configuration using toner may be used.

  The electrophotographic photosensitive member 1 is combined with one or more of the charging device 2, the exposure device 3, the developing device 4, the transfer device 5, the cleaning device 6, and the fixing device 7 to form an integrated cartridge ( The electrophotographic photosensitive member cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. In this case, for example, when the electrophotographic photosensitive member 1 and other members are deteriorated, the electrophotographic photosensitive member cartridge is removed from the main body of the image forming apparatus, and another new electrophotographic photosensitive member cartridge is mounted on the main body of the image forming apparatus. This facilitates maintenance and management of the image forming apparatus.

Hereinafter, the present invention will be described in more detail with reference to production examples, examples and comparative examples. In addition, the following examples are shown in order to explain the present invention in detail, and the present invention is not limited to the following examples unless it is contrary to the gist thereof.
<Production of compound having arylamine skeleton>
(Production Example 1: Production of exemplary compound CT-1)
Under a nitrogen atmosphere, a reflux tube and a Dean-stark water separator were sequentially set in the reactor, and 7.29 g (20 mmol) of N, N′-di (m-tolyl) benzidine, 8.63 g (44 mmol) of diphenylacetaldehyde, Each reactor was charged with 0.20 g of p-toluenesulfonic acid monohydrate and dissolved in 50 ml of xylene while stirring. Thereafter, the mixture was reflux dehydrated for 2 hours while maintaining 140 ° C., and cooled to room temperature. The reaction solution and toluene / demineralized water (v / v = 1: 1) were mixed and stirred and separated. The obtained organic layer was washed with 1N NaOH aqueous solution and separated, and the organic layer was further washed with demineralized water 2-3 times and separated. The solvent of the obtained organic layer was distilled off under reduced pressure, passed through flash column chromatography (silica gel 400 g, developing solvent: toluene / hexane = 1/2), and further purified by reprecipitation with methanol. After vacuum drying, the exemplified compound CT-1 was obtained as a yellow powder (yield 10.81 g, yield 75%, purity 99.5%). The purity was calculated from the simple area ratio value on the high performance liquid chromatography chart. The IR spectrum (JASCO FT / IR-350 spectrophotometer) of this compound is shown in FIG.

(Production Example 2: Production of Exemplified Compound CT-2)
Exemplified compound CT-2 was obtained as a yellow powder in the same manner as in Production Example 1, except that N, N′-di (p-tolyl) benzidine was used as a raw material. An IR spectrum (JASCO FT / IR-350 spectrophotometer) of this compound is shown in FIG.

(Production Example 3: Production of Exemplified Compound CT-3)
Exemplified compound CT-3 was obtained as a yellow powder in the same manner as in Production Example 1, except that N, N′-di [(3,4-dimethyl) phenyl] benzidine was used as a raw material. FIG. 4 shows the IR spectrum (JASCO FT / IR-350 spectrophotometer) of this compound.

(Production Example 4: Production of Exemplified Compound CT-4)
Exemplified compound CT-4 was obtained as a yellow powder in the same manner as in Production Example 1, except that N, N′-di [(2,4-dimethyl) phenyl] benzidine was used as a raw material. FIG. 5 shows the IR spectrum (JASCO FT / IR-350 spectrophotometer) of this compound.

(Production Example 5: Production of Exemplified Compound CT-5)
Exemplified compound CT-5 was obtained as a yellow powder in the same manner as in Production Example 1, except that N, N′-di [(2,5-dimethyl) phenyl] benzidine was used as a raw material. FIG. 6 shows the IR spectrum (JASCO FT / IR-350 spectrophotometer) of this compound.

(Production Example 6: Production of exemplary compound CT-12)
Exemplified compound CT-12 was obtained as a yellow powder in the same manner as in Production Example 1, except that the following compound was used as a raw material. FIG. 7 shows the IR spectrum (JASCO FT / IR-350 spectrophotometer) of this compound.

<Production of electrophotographic photoreceptor>
(Example 1: Electrophotographic photoreceptor A1)
Using a conductive support in which an aluminum vapor-deposited layer (thickness 70 nm) is formed on the surface of a biaxially stretched polyethylene terephthalate resin film (thickness 75 μm), the following undercoat layer dispersion is formed on the aluminum vapor-deposited layer of the conductive support The liquid was applied by a bar coater so that the film thickness after drying was 1.25 μm and dried to form an undercoat layer.

  The undercoat layer dispersion was prepared by the following method. That is, a rutile type titanium oxide having an average primary particle size of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by mass of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) with respect to the titanium oxide were flowed at high speed. By dispersing the surface-treated titanium oxide obtained by mixing at high speed at a rotational peripheral speed of 34.5 m / sec with a ball mill of methanol / 1-propanol. A dispersion slurry of hydrophobized titanium oxide was obtained. The dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam [compound represented by the following formula (A)] / bis (4-amino-3-methylcyclohexyl) methane [the following formula ( Compound represented by B)] / hexamethylenediamine [compound represented by the following formula (C)] / decamethylene dicarboxylic acid [compound represented by the following formula (D)] / octadecamethylene dicarboxylic acid [following formula The compound represented by (E)] has a composition molar ratio of 60% / 15% / 5% / 15% / 5% and is agitated and mixed with pellets of copolymerized polyamide to dissolve the polyamide pellets. Then, ultrasonic dispersion treatment is performed, so that the mass ratio of methanol / 1-propanol / toluene is 7/1/2, and the hydrophobically treated titanium oxide / copolymerized polyamid. Which contained a weight ratio 3/1 was undercoat layer dispersion having a solid concentration of 18.0%.

  Separately, type A oxytitanium phthalocyanine (diffraction peaks are shown at 9.3 °, 10.6 °, and 26.3 ° of the Bragg angle (2θ ± 0.2 °) in the X-ray diffraction spectrum for CuKa characteristic X-ray) 10 parts by mass was added to 150 parts by mass of 4-methoxy-4-methyl-2-pentanone, and pulverized and dispersed in a sand grind mill for 1 hour. Thereafter, 100 parts by mass of 5% by weight 1,2-dimethoxyethane solution of polyvinyl butyral (“Denkabutyral # 6000C” manufactured by Denki Kagaku Kogyo Co., Ltd.) as a binder resin, and phenoxy resin (“PKHH” manufactured by Union Carbide) A charge generation layer coating solution was prepared by adding 100 parts by mass of a 5 mass% 1,2-dimethoxyethane solution. The charge generation layer coating solution was applied onto the undercoat layer of the conductive support with a bar coater so that the film thickness after drying was 0.4 μm, and dried to form a charge generation layer. .

  Separately, 40 parts by mass of the exemplified compound CT-1 obtained in Production Example 1 as a charge transport material, 100 parts by mass of a binder resin, and 0.03 parts by mass of silicone oil as a leveling agent were added in tetrahydrofuran / toluene ( (Mass ratio 8/2) A charge transport layer coating solution was prepared by dissolving in 640 parts by mass of a mixed solvent. In addition, as binder resin, the repeating unit A51 mol% which uses the following 2, 2-bis (4-hydroxy-3-methylphenyl) propane as an aromatic diol component, and 1,1-bis (4-hydroxyphenyl) are shown. ) A polycarbonate resin (viscosity average molecular weight 30000) having a terminal structure derived from pt-butylphenol, comprising 49 mol% of a repeating unit B having 1-phenylethane as an aromatic diol component.

  The charge transport layer coating solution is applied onto the charge generation layer with a film applicator so that the film thickness after drying is 20 μm, and is dried to form a charge transport layer. Photoreceptor A1 was produced.

(Example 2: Electrophotographic photoreceptor A2)
An electrophotographic photoreceptor A2 as an example was obtained in the same manner as in Example 1 except that CT-2 was used as a charge transport material instead of the exemplified compound CT-1.

(Example 3: Electrophotographic photoreceptor A3)
An electrophotographic photoreceptor A3 as an example was obtained in the same manner as in Example 1 except that CT-3 was used as the charge transport material instead of the exemplified compound CT-1.

(Example 4: Electrophotographic photoreceptor A4)
An electrophotographic photoreceptor A4 as an example was obtained in the same manner as in Example 1 except that CT-4 was used as a charge transport material instead of the exemplified compound CT-1.

(Example 5: electrophotographic photoreceptor A5)
An electrophotographic photoreceptor A5 as an example was obtained in the same manner as in Example 1 except that CT-5 was used as a charge transport material instead of the exemplified compound CT-1.

(Example 6: electrophotographic photoreceptor A6)
An electrophotographic photoreceptor A6 as an example was obtained in the same manner as in Example 1 except that CT-12 was used as a charge transport material instead of the exemplified compound CT-1.

(Comparative Example 1: Electrophotographic photoreceptor P1)
An electrophotographic photoreceptor P1 as a comparative example was obtained in the same manner as in Example 1 except that the following charge transport material (a) exemplified in Patent Document 1 was used instead of the exemplified compound CT-1. .

(Comparative Example 2: Electrophotographic photoreceptor P2)
An electrophotographic photosensitive member P2 as a comparative example was obtained in the same manner as in Example 1 except that the following charge transport material (b) exemplified in Patent Document 2 was used in place of the exemplified compound CT-1. .

(Comparative Example 3: Electrophotographic photoreceptor P3)
An electrophotographic photosensitive member P3 as a comparative example was prepared in the same manner as in Example 1 except that the following charge transport material (c) exemplified in Patent Document 2 was used in place of the exemplified compound CT-1. However, the compatibility with the binder resin was poor and a cloudy coating solution was obtained. Thereafter, further crystals were precipitated during the application of the photoreceptor, and the measurement of the characteristics was not achieved.

<Evaluation of electrical characteristics of electrophotographic photoreceptor>
The electrophotographic characteristics of the obtained electrophotographic photoreceptors A1 to A6 and P1 to P3 were measured by the static method as follows using a photoreceptor evaluation apparatus (Cynthia-55, manufactured by Gentec Corporation).
First, the electrophotographic photosensitive member is discharged with a scorotron charger in a dark place so that the surface potential is about −700 V, charged through the electrophotographic photosensitive member at a constant speed (125 mm / sec), The voltage was measured and the initial charging voltage (V ₀ ) was determined. Thereafter, the potential drop (DDR) was measured when left for 2.5 seconds. Next, irradiation with 780 nm monochromatic light having an intensity of 1.0 μW / cm ² , irradiation with half-exposure energy E1 / 2 (μJ / cm ² ) required until the photoreceptor surface potential is changed from −550 V to −275 V, and irradiation The residual potential (Vr) after 10 seconds was determined.
Table 2 shows the evaluation results of the electrophotographic photoreceptors A1 to A6 and P1 to P3.

  As shown in Table 2, the electrophotographic photoconductors A1 to A6 are more sensitive than the electrophotographic photoconductors P1 and P2 with a low half-exposure energy, and 10 seconds after exposure light irradiation. The residual voltage Vr was more preferable at a low value. Therefore, an electron using the exemplary compounds CT-1, CT-2, CT-3, CT-4, CT-5, CT-12, which are compounds represented by the formula [I] according to the present invention, as a charge transport material The photographic photoreceptors A1 to A6 are more suitable for electrophotographic devices in terms of electrical characteristics than the electrophotographic photoreceptors using the charge transport materials a and b having a similar structure or geometric isomers. Moreover, it turns out that the compound represented by the formula [I] according to the present invention exhibits better solubility than the known enamine charge transport material c.

<Evaluation of responsiveness>
With respect to the obtained electrophotographic photoreceptors A1 to A6 and P1 to P2, the electric field strength E = 2.0 + 5E (V / cm) of the charge transport layer and the hole drift mobility at a temperature of 21 ° C. were measured by the TOF method. Table 3 shows the hole drift mobilities of the electrophotographic photoreceptors A1 to A6 and P1 to P2.

  As shown in Table 3, the electrophotographic photoreceptors A1 to A6 have a higher hole drift mobility than the electrophotographic photoreceptors P1 to P2. Therefore, an electron using the exemplary compounds CT-1, CT-2, CT-3, CT-4, CT-5, CT-12, which are compounds represented by the formula [I] according to the present invention, as a charge transport material The photographic photoreceptors A1 to A6 are more suitable for an electrophotographic apparatus in terms of responsiveness than the electrophotographic photoreceptors using the charge transport materials a and b having a similar structure or geometric isomers.

<Image formation test and photoreceptor stability / durability test>
(Examples 7 to 8)
The coating solution for the charge generation layer and the charge transport layer prepared in the same manner as the electrophotographic photoreceptors A4 and A6 is immersed in an aluminum tube having a diameter of 3 cm and a length of 25.4 cm, which is anodized and sealed. The electrophotographic photosensitive drums having a film thickness of 0.3 μm and a charge transport layer of 20 μm were prepared as Examples 7 to 8, respectively, by coating and drying sequentially by a coating method. When these electrophotographic photosensitive drums were mounted on a laser printer, Laser Jet 4 (LJ4) manufactured by Hewlett-Packard Co., and an image test was performed, good images without any image defects or noise were obtained. Subsequently, 10,000 sheets were continuously printed, and all of them were stable with no image deterioration such as ghost, fog, and black spots.

(Comparative Examples 4-5)
The electrophotographic photosensitive drum was used as Comparative Examples 4 to 5 in the same procedure as in Examples 7 to 8, except that those prepared in the same manner as the electrophotographic photosensitive members P1 and P2 were used as the charge transport layer coating solution. When produced and subjected to an image test, good images without image defects and noise were obtained. However, when 10,000 sheets were continuously printed, fogging defects were observed in Comparative Example 4. In Comparative Example 5, the ghost was significantly changed.

  From Examples 7 to 8 and Comparative Examples 4 to 5, the electrophotographic photosensitive member using the known enamine compounds a and b has a problem in repetitive characteristics and is difficult to use, but the formula [I It was confirmed that the electrophotographic photosensitive member using the compound represented by the above formula has excellent repetitive characteristics.

  While the present invention has been described in connection with embodiments that are presently the most practical and preferred, the present invention is not limited to the embodiments disclosed herein. The electrophotographic photosensitive member and the image forming apparatus accompanying such changes are also within the technical scope of the present invention, and can be appropriately changed without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. Must be understood as encompassed by.

  The present invention can be carried out in any field that requires an electrophotographic photoreceptor, and is suitably used for, for example, a copying machine, a printer, a printing machine, and the like.

1 is a schematic diagram illustrating a main configuration of an embodiment of an image forming apparatus of the present invention. It is IR spectrum of exemplary compound CT-1 of this invention. It is IR spectrum of exemplary compound CT-2 of this invention. It is IR spectrum of exemplary compound CT-3 of this invention. It is IR spectrum of exemplary compound CT-4 of this invention. It is IR spectrum of exemplary compound CT-5 of this invention. It is IR spectrum of exemplary compound CT-12 of this invention.

Explanation of symbols

1 Photoconductor (Electrophotographic photoconductor)
2 Charging device (charging roller; charging unit)
3 Exposure equipment (exposure section)
4 Development device (development unit)
DESCRIPTION OF SYMBOLS 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 (paper, medium)

Claims (2)

An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer contains at least one enamine compound represented by the general formula [I]. .

(In the formula [I], Ar ^{1 to} Ar ⁶ may be the same or different, each having 1 to 10 carbon atoms and a substituent constant σp in the Hammett rule of 0.20 or less. And n represents an integer of 2 or 3 , Z represents a monovalent organic residue, and m represents an integer of 0 to 4. However, Ar ^{1 to} Ar ² Among them, at least one is an aryl group having a substituent having 1 to 10 carbon atoms and having a substituent constant σp of 0.20 or less in Hammett's rule . 2. The electrophotographic photosensitive member according to claim 1, a charging unit for charging the electrophotographic photosensitive member, an exposure unit for exposing the charged electrophotographic photosensitive member to form an electrostatic latent image, and the electrophotography by exposure. An image forming apparatus comprising: a developing unit that develops an electrostatic latent image formed on a photoreceptor using toner.

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