JP2009169023A - Electrophotographic photoreceptor and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which is: (1) good at solubility in a solvent of a charge transport material so that a photoreceptive layer can be manufactured well; (2) good at such electric characteristics as the sensitivity to light of the photoreceptive layer formed, residual potential, and charge mobility; and (3) excellent in potential stability and environmental stability when preserved. <P>SOLUTION: The electrophotographic photoreceptor has a photoreceptive layer on conductive support. The photoreceptive layer contains at least one of compound having a terphenyl skeleton represented by general formula (1). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrophotographic photoreceptor and an image forming apparatus. Specifically, the present invention relates to an electrophotographic photosensitive member provided with a photosensitive layer containing an arylamine compound having a terphenyl skeleton, and an image forming apparatus provided with the electrophotographic photosensitive member.

  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 photosensitive member that is the core of the electrophotographic technology, an electrophotographic photosensitive member using an organic photoconductive material (hereinafter simply referred to as “electrified”) having advantages such as non-pollution, easy film formation, and easy manufacture. In some cases, it is referred to as a “photoconductor”.

  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. Multilayer photoreceptors are known. Laminated photoconductors can be divided into separate layers for charge generation materials and charge transport materials, and select and combine the most efficient ones to obtain highly sensitive and stable photoconductors. This is the mainstream of photoconductors because of the fact that it is possible to obtain photoconductors whose characteristics can be easily adjusted due to its wide area, and that the photosensitive layer can be easily formed by coating, has high productivity, and is advantageous in terms of cost. Is used a lot.

  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 it requires fewer coating processes and is effective against interference fringes and tube defects derived from a conductive substrate (support), and is inexpensive such as an uncut tube (support). There is an advantage that the cost can be reduced.

In addition, the electrophotographic photosensitive member deteriorates because it is repeatedly used in an electrophotographic process, that is, a cycle such as charging, exposure, development, transfer, cleaning, and static elimination, and receives various stresses. 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.
Due to this damage, in repeated use, electrical stability such as a decrease in chargeability and an increase in residual potential, and an accompanying image defect may occur. These defects are largely caused by chemical deterioration of the charge transport material contained in the photosensitive layer.

  Furthermore, with the recent speeding up of the electrophotographic process, it is essential to increase the sensitivity and speed of the electrophotographic photosensitive member. Among these, in order to increase the sensitivity, it is necessary not only to optimize the charge generation material, but also to develop a charge transport material having a good matching with the charge generation material. In order to achieve high-speed response, it is necessary to develop a charge transport material that exhibits high mobility, high sensitivity, and a sufficiently low residual potential during exposure.

  As a conventional technique, it is disclosed that an arylamine compound having a terphenyl skeleton can be used as a charge transport material (for example, Patent Documents 1 to 3).

  However, the arylamine-based compound group described in Patent Document 1 has the disadvantages that electric characteristics such as photosensitivity and residual potential are still insufficient and the charge mobility is relatively slow. Further, when the phenyl group at the molecular end has an alkoxy group and an alkyl group at the same time, the arylamine compound may be easily oxidized because the ionization potential of the molecule is too low.

  Therefore, an electrophotographic photoreceptor using this arylamine compound as a charge transporting material has insufficient electrical characteristics or responsiveness, or when used repeatedly, the acid gas resistance deteriorates and the charging property is low. A great problem arises in the stability of electrical characteristics such as a decrease and an increase in residual potential.

In addition, the arylamine compound group described in Patent Document 2 or 3 has problems in solubility in a solvent at the time of production of the photoreceptor and stability of the formed coating solution. It was not satisfactory as a material.
WO2005-115970 JP 2001-305664 A WO2007-063989

  The present invention has been made in view of the above-mentioned present situation. (1) Since the solubility of the charge transporting material in the solvent is good, a photosensitive layer can be produced satisfactorily. (2) The light of the formed photosensitive layer Provided are an electrophotographic photosensitive member having excellent electrical characteristics such as sensitivity, residual potential, and charge mobility, and (3) excellent durability and environmental stability, and an image forming apparatus including the photosensitive member. The task is to do.

  As a result of intensive studies to solve the above problems, the present inventors have introduced a short-chain alkyl substituent at the ortho position of the terminal phenyl group directly connected to the nitrogen atom of the arylamine compound having a terphenyl skeleton, The inventors have found that the above problems can be solved, and have completed the following present invention.

  The first aspect of the present invention is an electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains at least a compound having a terphenyl skeleton represented by the following general formula (1). An electrophotographic photosensitive member characterized by containing one kind.

（一般式（１）中、Ａｒ^１およびＡｒ^２は、互いに同一でも異なっていてもよく、Ｈａｍｍｅｔｔ則における置換基定数σｐが０．２０以下である置換基を有していてもよいアリール基を表し、Ｒ^１およびＲ^２は、互いに同一でも異なっていてもよく、炭素数１〜３のアルキル基を表し、ＸおよびＹは、互いに同一でも異なっていてもよく、置換基を有していてもよいアルキル基を表し、ｍおよびｎは、ＸおよびＹで表される置換基の数を表し、それぞれ１〜４の整数を表す。ただし、ＸとＲ^１とが、および／または、ＹとＲ^２とが、互いに環を形成する場合、ならびに、Ａｒ^１およびＡｒ^２が、窒素原子に対してオルト位に置換基を同時に有する場合を除く。）。

(In the general formula (1), Ar ¹ and Ar ² may be the same or different from each other, and an aryl group which may have a substituent having a substituent constant σp of 0.20 or less in Hammett's rule) R ¹ and R ² may be the same as or different from each other, and represent an alkyl group having 1 to 3 carbon atoms, X and Y may be the same as or different from each other, and have a substituent. M and n represent the number of substituents represented by X and Y, and each represents an integer of 1 to 4, provided that X and R ¹ and / or Y and Except when R ² forms a ring with each other and when Ar ¹ and Ar ² simultaneously have a substituent at the ortho position with respect to the nitrogen atom).

  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 electrophotographic photoreceptor of the present invention can be produced satisfactorily because (1) the solubility of the charge transport material (compound having a terphenyl skeleton) in the solvent is good. In addition, since the photosensitive layer includes a compound having a terphenyl skeleton as a charge transport material, (2) electrical characteristics such as photosensitivity, residual potential, and charge mobility are good. (3) Furthermore, it is excellent in potential stability during durability and environmental stability. The electrophotographic photoreceptor of the present invention can be implemented 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.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

<Electrophotographic photoreceptor>
The electrophotographic photoreceptor of the present invention comprises a photosensitive layer on a conductive support, and the photosensitive layer contains at least one compound having a specific terfinyl skeleton. Hereinafter, first, a compound having a specific terphenyl skeleton contained in the photosensitive layer will be described.

(Compound having terphenyl skeleton)
In the present invention, the compound having a terphenyl skeleton (arylamine compound) contained in the photosensitive layer is a compound represented by the following general formula (1).

In the general formula (1), Ar ¹ and Ar ² may be the same as or different from each other, and each represents an aryl group which may have a substituent having a substituent constant σp of 0.20 or less in the Hammett rule. . The aryl group constituting Ar ¹ and Ar ² is preferably an aryl group having 6 to 20 carbon atoms, and examples thereof include phenyl, naphthyl, fluorenyl, anthryl, phenanthryl, and pyrenyl. From the viewpoint of production cost, aryl groups having 6 to 10 carbon atoms such as phenyl and naphthyl are particularly preferable. Furthermore, when Ar ¹ and Ar ² have a substituent, the substituent is preferably a substituent having 1 to 10 carbon atoms and a substituent constant σp in the Hammett rule of 0.20 or less. In addition, when Ar ¹ and Ar ² simultaneously have a substituent in the ortho position with respect to the nitrogen atom, the conjugation of the triarylamine part is completely cleaved, which is not preferable in terms of electrical characteristics and charge mobility. Excluded from the scope of the present invention.

  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 the 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 (Edited by Chemical Society of Japan, “Basic Manual II, Revised 4th Edition”, Maruzen Co., Ltd., published on September 30, 1993, p.364-365). .

  Examples of such a substituent include 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, an aryl group having 6 to 10 carbon atoms, 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. Among these, an alkyl group having 1 to 4 carbon atoms is particularly preferable from the viewpoint of electrical characteristics.

In general formula (1), R ¹ and R ² may be the same as or different from each other, and represent an alkyl group having 1 to 3 carbon atoms. Examples of R ¹ and R ² include methyl, ethyl, n-propyl, and isopropyl. Among them, a methyl group is particularly preferable in terms of electrical characteristics.

  In general formula (1), X and Y may be the same as or different from each other, and represent an alkyl group which may have a substituent. The alkyl group constituting X and Y is preferably an alkyl group having 1 to 4 carbon atoms, and examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl and the like. Among these, a methyl group is particularly preferable in terms of production cost. Furthermore, when the alkyl group has a substituent, the substituent is preferably a substituent having 1 to 10 carbon atoms and a substituent constant σp in the Hammett rule of 0.20 or less.

In general formula (1), m and n represent the number of substituents represented by X and Y, and each represents an integer of 1 to 4. m and n are each preferably an integer of 1 to 2. Among these, from the viewpoint of electrical characteristics and manufacturing cost, m = n = 1 is particularly preferable. However, when X and R ¹ and / or Y and R ² form a ring with each other, it is not preferable in terms of electrical characteristics, and is excluded from the scope of the present invention.

  As typical examples of the arylamine compound having a terphenyl skeleton represented by the general formula (1), the following exemplified compounds (CT-1 to CT-7) may be mentioned. However, the compounds related to the present invention are not limited to these compounds.

  These arylamine compounds having a terphenyl skeleton 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.

  As shown in the above reaction formula, 4,4 ″ -diiodo-p-terphenyl (A) and diarylamine derivative (B) are condensed in the presence of a palladium-trialkylphosphine complex catalyst to obtain the target product. Charge transport material CT-1 can be obtained.

  The configuration of the electrophotographic photosensitive member of 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 triarylamine compound described above is provided on a conductive support, but the charge generation layer, A laminate type photoreceptor in which a charge transport layer is laminated is preferable, and in particular, the charge transport layer preferably contains the triarylamine compound.

(Conductive support)
There are no particular restrictions on the conductive support, but for example, metal materials such as aluminum, aluminum alloy, stainless steel, copper and nickel, and conductive powders such as metal, carbon and tin oxide are added to provide conductivity. Mainly used are resin, glass, paper, or the like obtained by depositing or applying a conductive material such as aluminum, nickel, or ITO (indium tin oxide) to the surface. These may be used alone or in combination of two or more in any combination and ratio. Examples of the conductive support include a drum shape, a sheet shape, and a belt shape. Furthermore, 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 preferable 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. Further, in order to reduce the cost, it is possible to use the drawing tube as it is without performing a cutting process or the like.

(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 silicone. 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 them, the average primary particle diameter is preferably 10 nm or more and 100 nm or less, and more preferably 10 nm or more and 50 nm or less from the viewpoint of characteristics and liquid stability.

  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 resin. Vinylidene resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, polyacrylamide resin, polyvinyl pyrrolidone resin, polyvinyl pyridine resin, water-soluble polyester resin, cellulose ester resin such as nitrocellulose, cellulose ether resin, casein , Gelatin, polyglutamic acid, starch, starch acetate, amino starch, zirconium chelate compounds, zirconium alkoxide compounds, etc. Beam compounds, titanyl chelate compounds, organic titanyl compounds such as titanium alkoxide compounds include known binder resins such as a 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 ratio of the metal oxide particles to the binder resin in the undercoat layer is not particularly limited. From the viewpoint of dispersion stability and coatability, the metal oxide particles are 10% by mass based on the binder resin (100% by mass). It is preferable to set it to 500 mass% or less.

  The thickness of the undercoat layer is not particularly limited, but is preferably 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. Further, 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. And a functional separation type (laminated type) composed of two layers of a charge transport layer in which a transport material is dispersed in a binder resin. In the present invention, it is preferable to employ a function-separated type (laminated type) photosensitive layer.

  In addition, as the laminated type photosensitive layer, the charge generating layer and the charge transport layer are laminated in this order from the conductive support side, and conversely, the charge transport layer and the charge generation layer from the conductive support side. There is a reverse lamination type photosensitive layer that is laminated in this order, and any of them can be adopted, but a normal lamination type photosensitive layer that can exhibit the most balanced photoconductivity is preferred.

(Laminated photosensitive layer)
[Charge generation layer]
In the case of a laminated 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 selenium and its alloys, inorganic photoconductive materials such as cadmium sulfide, and organic photoconductive materials such as organic pigments. Among these, organic photoconductive materials are preferable, and organic pigments are particularly preferable. 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. Examples of phthalocyanine pigments include metal-free phthalocyanine pigments and metal-containing phthalocyanine pigments. Examples of azo pigments include monoazo pigments, bisazo pigments, and trisazo pigments. 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 phthalocyanine pigment is used as the charge generation material, a highly sensitive photoreceptor can be obtained with respect to a laser beam having a relatively long wavelength, for example, a laser beam having a wavelength around 780 nm. When an azo pigment is used, for white light, laser light having a wavelength around 660 nm, or laser light having a relatively short wavelength (for example, laser light having a wavelength in the range of 380 nm to 500 nm). A photoreceptor having sufficient sensitivity can be obtained.

  Specific examples of phthalocyanine pigments that are charge generation materials include metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, aluminum, and other metals or oxides, halides, hydroxides thereof. And phthalocyanine dimers using an oxygen atom or the like as a bridging atom, or the like. Particularly, 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 °. Or D-type (also called Y-type) titanyl phthalocyanine, II-type chlorogallium phthalocyanine, and V-type, each having a strong peak at 28.1 °, or 26. Hydroxygallium phthalocyanine having no peak at 2 °, 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.

  As the phthalocyanine compound, a single compound may be used, two or more kinds may be mixed and used, or those in a mixed crystal state may be used. As the mixed or mixed crystal state, those obtained by mixing the respective constituent elements later may be used, or a mixed state is generated in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, and crystallization. There may be. Acid paste treatment, grinding treatment, solvent treatment, and the like are known as treatment processes for phthalocyanine compounds. 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.

  As the azo pigment which is a charge generating substance, 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, and among them, a bisazo 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. For example, polyvinyl butyral resin, polyvinyl formal resin, partially modified polyvinyl acetal resin, polyarylate resin, polycarbonate resin, polyester resin, modified ether polyester resin, phenoxy resin, polychlorinated resin. Vinyl 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, Polyvinylpyrrolidone resin, casein, vinyl chloride-vinyl acetate copolymer, hydroxy-modified vinyl chloride-vinyl acetate copolymer, carboxyl-modified vinyl chloride Vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer such as vinyl chloride-vinyl acetate-maleic anhydride copolymer, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, styrene-alkyd resin, Examples thereof include insulating resins such as silicone-alkyd resins and phenol-formaldehyde resins, and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinyl anthracene, and polyvinyl 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 above charge generation material in a solution obtained by dissolving the above binder resin in an organic solvent to prepare a coating solution, which is then placed on the conductive support (with an undercoat layer). If provided, 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 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, Acetic acid n- Chains such as ester solvents such as chill, halogenated hydrocarbon solvents such as methylene chloride, chloroform, 1,2-dichloroethane, diethyl ether, dimethoxyethane, tetrahydrofuran, 1,4-dioxane, methyl cellosolve, ethyl cellosolve, etc. Or cyclic ether solvents, acetonitrile, dimethylsulfoxide, sulfolane, aprotic polar solvents such as hexamethylphosphoric triamide, n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine, triethylenediamine, triethylamine and other nitrogen-containing compounds Compound, mineral oil such as ligroin, water and the like. Any of these may be used alone or in combination of two or more. In addition, when providing the above-mentioned undercoat layer, it is preferable that the solvent does not dissolve this undercoat layer.

  In the charge generation layer, the ratio 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 the upper limit is usually 1000 parts by mass with respect to 100 parts by mass of the binder resin. It is not more than part by mass, preferably not more than 500 parts by mass. 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. The lower limit of the thickness of the charge generation layer is usually 0.1 μm or more, preferably 0.15 μm or more, and the upper limit is usually 10 μm or less, preferably 0.6 μm or less.

  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 make the particles finer to a particle size 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 photoreceptor 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, the above-described compound having a terphenyl skeleton is used. As the compound having a terphenyl skeleton, one kind may be used alone, or a plurality of kinds may be mixed and used in an arbitrary combination and ratio. In addition to the compound having a terphenyl skeleton, other known charge transport materials may be used in combination. When other charge transport materials are used in combination, the type is not particularly limited, but for example, carbazole derivatives, hydrazone compounds, aromatic amine derivatives, stilbene derivatives, butadiene derivatives and those in which a plurality of these derivatives are bonded 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 other known charge transport materials may be used alone, or a plurality of types may be used in any combination.

  In the case where a compound having a terphenyl skeleton and another known charge transport material are used in combination, the content ratio of the other known charge transport material is 1% by mass or more and 20% by mass based on the total amount of the charge transport material. % Or less, and more preferably 3% by mass or more and 10% by mass or less from the viewpoint of more effectively exerting the role of the compound having a terphenyl skeleton.

  In the charge transport layer, the binder resin is used to ensure film strength. Examples of the binder resin for the charge transport layer include polymers and copolymer of 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. Polymer, 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- 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 charge transport material in the charge transport layer is usually 20 parts by mass or more when the binder resin is 100 parts by mass. 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 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 more preferable from the viewpoint of scratch resistance.

  The thickness of the charge transport layer is not particularly limited, but from the viewpoint of long life, image stability, and high resolution, the lower limit is usually 5 μm or more, preferably 10 μm or more, and the upper limit is usually 50 μm or less, preferably 45 μm or less. Preferably it is 30 micrometers or less.

<Single layer type photosensitive layer>
The single-layer type photosensitive layer is formed by using a binder resin for ensuring film strength 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). By applying and drying, a single-layer type photosensitive layer can be obtained.

  As the charge transport material and the binder resin, the same materials as those described in the charge transport layer of the multilayer photoreceptor are used. Further, the ratio of use thereof is the same as that in the charge transport layer of the multilayer photoreceptor. A charge generation 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 in the charge generation layer of the multilayer photoreceptor are 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, it 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. On the other hand, if the amount is too large, there are problems such as a decrease in chargeability and a decrease in sensitivity. For this reason, the lower limit of the amount of the charge generating material dispersed in the single-layer type photosensitive layer is usually 0.5% by mass or more, preferably 1% by mass, based on the whole single-layer type photosensitive layer (100% by mass). In addition, the upper limit is usually 50% by mass or less, preferably 20% by mass or less.

  The 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 30 parts per 100 parts by mass of the binder resin. It is made into the range below 10 mass parts, preferably below 10 mass parts.

  The lower limit of the thickness of the monolayer type photosensitive layer is usually 5 μm or more, preferably 10 μm or more, and the upper limit is usually 100 μm or less, preferably 50 μm or less.

(Other functional layers)
For the purpose of improving the film formability, flexibility, coatability, contamination resistance, gas resistance, light resistance, etc., in both the photosensitive layer and each layer constituting it, both in the multilayer type photoreceptor and the single layer type photoreceptor. 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 multilayer 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 thereon, and this may be 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 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 a lot of fog. 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 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, silicone resin, polyethylene resin, or the like. You may contain the particle | grains which consist of these resin, and the particle | grains of an inorganic compound. 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 repeating a coating / drying step for each layer sequentially on a conductive support obtained by dissolving or dispersing a substance to be contained in a solvent.

  There is no particular limitation on the solvent or dispersion medium used for the preparation of the coating solution, for example, alcohols such as methanol, ethanol, propanol and 2-methoxyethanol, ethers such as tetrahydrofuran, 1,4-dioxane and dimethoxyethane, Esters such as methyl formate and ethyl acetate, ketones such as acetone, methyl ethyl ketone, cyclohexanone and 4-methoxy-4-methyl-2-pentanone, aromatic hydrocarbons such as benzene, toluene and xylene, dichloromethane, chloroform, 1 , 2-dichloroethane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichlorethylene and other chlorinated hydrocarbons, 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 be used in combination of 2 or more types arbitrarily.

  The amount of the solvent or the 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 appropriately determined so that the physical properties such as the 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 single layer type photoreceptor and a charge transport layer of 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. Hereinafter, 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, usually in the temperature range of 30 ° C. or more and 200 ° C. or less, and for 1 minute or more and 2 hours or less, while still or blowing. Moreover, the heating temperature at the time of drying may be constant or may be changed with time.

<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.

  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 photosensitive member 1 is not particularly limited as long as it is the above-described electrophotographic photosensitive member of the present invention. In FIG. 1, as an example, the above-described photosensitive layer is formed on the surface of a cylindrical conductive support. A drum-shaped photoreceptor 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) for charging a charged member by directly contacting the charged member surface with the surface of the photosensitive member, etc. are 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 a means for direct charging, either charging with air discharge or injection charging without air discharge is possible. Moreover, as a voltage applied at the time of charging, only a DC voltage may be used, or an alternating current may be superimposed 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 at the time of exposure is arbitrary, but for example, exposure may be performed with monochromatic light with a wavelength of 780 nm, monochromatic light with a wavelength slightly shorter than 600 nm to 700 nm, monochromatic light with a wavelength shorter than 380 nm to 500 nm, or the like. .

  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 is configured to store toner T 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. This 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 photosensitive member 1 and the supply roller 43 and is in contact with the electrophotographic photosensitive member 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 a silicone resin or a 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 a 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 having different blade shapes and sizes may be provided.

  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. . In FIG. 1, the transfer device 5 is illustrated as including a transfer charger, a transfer roller, a transfer belt, and the like 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. However, when there is little or almost no toner remaining on the surface of the photoreceptor, the cleaning device 6 may not be provided.

  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. As the upper and lower fixing members 71 and 72, known heat such as 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, or a fixing sheet is used. A fixing member can be used. Further, the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve the 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 P. The toner is fixed on the top.

  The type of the fixing device is not particularly limited, and a fixing device of an arbitrary method such as heat roller fixing, flash fixing, oven fixing, pressure fixing, or the like can be provided.

  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.

  Further, the image forming apparatus may be further modified, 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 a main body of an electrophotographic apparatus 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.

<Production of compound having terphenyl skeleton>
(Production Example 1: Production of exemplary compound CT-1)
Under a nitrogen atmosphere, 7.23 g (15 mmol) of 4,4 ″ -diiodo-p-terphenyl A and 6.97 g (33 mmol) of diarylamine derivative B described in the production method of Exemplified Compound CT-1, 50 ml of xylene, sodium-tert -3.17 g (33 mmol) of butoxide was charged into the reactor, and 1 ml of a xylene solution containing 0.7 mg of palladium acetate and 2.35 mg of tri-tert-butylphosphine was added to the mixed solution with stirring. The reactor was heated to 145 ° C. and continued to react for 2 to 3 hours at that temperature, followed by reaction, cooling, and adding 50 ml of toluene and 50 ml of water to separate the organic layer. After washing with magnesium sulfate three times, drying with contact with magnesium sulfate, the solution was concentrated under reduced pressure. / Hexane (v / v = 1: 1) was dissolved in heat and then passed through column chromatography (silica gel 250 g, developing solvent: toluene / hexane = 1/1) to obtain the above exemplified compound CT-1. (9.15 g, 14.1 mmol, 94% yield) The IR spectrum (JASCO FT / IR-350 spectrophotometer) of this compound is shown in FIG.

<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, by performing ultrasonic dispersion treatment, the mass ratio of methanol / 1-propanol / toluene is 7/1/2, and the hydrophobically treated titanium oxide / copolymerized polymer Containing de mass ratio 3/1 was undercoat layer dispersion having a solid concentration of 18.0%.

  A-type oxytitanium phthalocyanine (shows diffraction peaks at 9.3 °, 10.6 °, and 26.3 ° of Bragg angles (2θ ± 0.2 °) in the X-ray diffraction spectrum for CuKα characteristic X-ray) 10 The mass part 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 a 5 mass% 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. .

  Further, 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 the 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.

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

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

(Comparative Example 3: Electrophotographic photoreceptor P3)
An electrophotographic photoreceptor P3 as a comparative example was prepared in the same manner as in Example 1 except that the following charge transport material (comp-3) exemplified in Patent Document 1 was used instead of the exemplified compound CT-1. Obtained.

(Comparative Example 4: Electrophotographic photoreceptor P4)
An electrophotographic photosensitive member P4 as a comparative example was prepared in the same manner as in Example 1 except that the following charge transport material (comp-4) exemplified in Patent Document 1 was used in place of the exemplified compound CT-1. Obtained.

(Comparative Example 5: electrophotographic photoreceptor P5)
An electrophotographic photosensitive member P5 as a comparative example was prepared in the same manner as in Example 1 except that the following charge transport material (comp-5) exemplified in Patent Document 3 was used instead of the exemplified compound CT-1. Although obtained, crystals were deposited after the photoreceptor was coated. Attempts were made to measure the electrical characteristics of this photoreceptor, but no optical attenuation was observed, and the characteristics could not be measured.

＜電子写真感光体の電気特性評価＞
得られた電子写真感光体Ａ１、Ｐ１〜Ｐ５の電子写真特性を、感光体評価装置（シンシア−５５、ジェンテック社製）を用いて、スタティック方式でそれぞれ以下のようにして測定した。

<Evaluation of electrical characteristics of electrophotographic photoreceptor>
The electrophotographic characteristics of the obtained electrophotographic photoreceptors A1 and P1 to P5 were measured by a 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), measure the voltage, was determined the initial band voltage (V _0). 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 and half exposure energy E _1/2 (μJ / cm ² ) required until the photoreceptor surface potential is changed from −550 V to −275 V, The residual potential (Vr) 10 seconds after irradiation was determined. The smaller the half exposure energy E1 _{/ 2} and the residual potential (Vr) value 10 seconds after irradiation, the better the electrical characteristics.

  Table 2 shows the evaluation results of the electrophotographic photoreceptors A1 and P1 to P5.

  As shown in Table 2, the electrophotographic photoreceptor A1 of the present invention showed excellent results in the half-exposure energy or the residual voltage Vr after 10 seconds of irradiation, compared to the electrophotographic photoreceptors P1 to P4 of the comparative examples. . In addition, since the electrophotographic photosensitive member P5 had crystals precipitated, light attenuation was hardly observed, and the characteristics were not measured.

  As described above, the electrophotographic photosensitive member A1 of the present invention using the exemplified compound CT-1 which is a compound having a predetermined terphenyl skeleton as a charge transport material is an analog charge transport material (comp-1 to comp-5). It was found that the electrophotographic photosensitive member using) is superior in terms of electrical characteristics or compatibility with the binder resin.

<Evaluation of responsiveness>
For the photoconductors obtained in Example A1 and Comparative Examples P1 to P4, the electric field strength E = 2.0 × 10 ⁵ (V / cm) of the charge transport layer and the hole drift mobility at a temperature of 21 ° C. were measured by the TOF method. It was measured. Table 3 shows the hole drift mobility of each electrophotographic photosensitive member A1, P1 to P4.

表３に示すように、本発明の電子写真感光体Ａ１は、比較例の電子写真感光体Ｐ１〜Ｐ４に比べ、ホールドリフト移動度が速い。これより、本発明の電子写真感光体は、応答性の面においても優れていることが分かった。

As shown in Table 3, the electrophotographic photoreceptor A1 of the present invention has a higher hole drift mobility than the electrophotographic photoreceptors P1 to P4 of the comparative examples. From this, it was found that the electrophotographic photosensitive member of the present invention is excellent in terms of responsiveness.

<Evaluation of ozone resistance>
The method of ozone exposure test is described below. Using the EPA8200 manufactured by Kawaguchi Electric Co., the photoreceptors (A1, P1, and P2) obtained in Example 1 and Comparative Examples 1 and 2 were charged by applying a current of 25 μA to the corotron charger, and the charging The value was V1. Thereafter, ozone having a concentration of 150 ppm was exposed to these photoreceptors for 5 hours a day for 2 days (total exposure amount 750 ppm · hour), and the charge value was measured in the same manner after the exposure, and this value was designated as V2. Table 4 shows the charge retention before and after ozone exposure [(V2 / V1) × 100] (%). Similarly to the electrical property evaluation method described above, after 10 seconds of exposure, residual potentials before and after ozone exposure (respectively Vr1 and Vr2) are measured, and the difference ΔVr (Vr2−Vr1) is obtained. It was.

  As shown in Table 4, the electrophotographic photoreceptor A1 has a higher charge retention before and after ozone exposure than the electrophotographic photoreceptors P1 and P2, and the difference in residual potential after 10 seconds of exposure is small. Therefore, the electrophotographic photosensitive member A1 using the exemplary compound CT-1 which is an arylamine compound having a terphenyl skeleton of the present invention as a charge transport material uses the charge transport materials comp-1 and comp-2 as analogs. It was confirmed that the electrophotographic photoreceptor has better ozone resistance and better electrical stability.

<Image formation test and photoreceptor stability / durability test>
(Example 2)
A coating solution for a charge generation layer and a charge transport layer prepared in the same manner as the electrophotographic photoreceptor A1 is dip-coated on an aluminum tube having a diameter of 3 cm and a length of 25.4 cm, which has been anodized and sealed. Were sequentially coated and dried to produce an electrophotographic photosensitive drum having a film thickness of 0.3 μm and a charge transport layer of 20 μm. When this electrophotographic photosensitive drum was mounted on a laser printer, Laser Jet 4 (LJ4) manufactured by Hewlett-Packard Co., and an image test was performed, a good image free from image defects and noise was obtained. Subsequently, 10,000 sheets were continuously printed, but no image deterioration such as ghosting, fogging, and black spots was observed, and the printing was stable.

(Comparative Example 5)
In the procedure of Example 2, an electrophotographic photosensitive drum was prepared in the same procedure as in Example 2 except that the charge transport layer coating solution was prepared in the same manner as in the electrophotographic photosensitive member P3 (Comparative Example 3). Then, when an image test was performed, a good image free from image defects and noise was obtained. Next, when 10,000 sheets were continuously printed, white spots were generated in the halftone, and deterioration in image quality was recognized.

(Comparative Example 6)
In the procedure of Example 2, an electrophotographic photosensitive drum was prepared in the same procedure as in Example 2, except that the charge transport layer coating solution was prepared in the same manner as in the electrophotographic photosensitive member P2 (Comparative Example 2). Then, when an image test was performed, a good image free from image defects and noise was obtained. Next, when 10,000 sheets were continuously printed, image flow occurred and the resolution was remarkably lowered.

  From Example 2 and Comparative Examples 5 and 6, the electrophotographic photoreceptors P2 and P3 have problems in repeatability and are difficult to use, but the electrophotographic photoreceptor A1 which is an example of the present invention has excellent repeatability. It was confirmed to have

  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.

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.

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 compound having a terphenyl skeleton represented by the following general formula (1). An electrophotographic photoreceptor.

(In the general formula (1), Ar ¹ and Ar ² may be the same or different from each other, and an aryl group which may have a substituent having a substituent constant σp of 0.20 or less in Hammett's rule) R ¹ and R ² may be the same as or different from each other, and represent an alkyl group having 1 to 3 carbon atoms, X and Y may be the same as or different from each other, and have a substituent. M and n represent the number of substituents represented by X and Y, and each represents an integer of 1 to 4, provided that X and R ¹ and / or Y and Except when R ² forms a ring with each other and when Ar ¹ and Ar ² simultaneously have a substituent at the ortho position with respect to the nitrogen atom). 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.

Images