JP2007164090A - Electrophotographic photoreceptor and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having excellent electrical characteristics and an image forming apparatus with which high quality image formation processing is possible by using the electrophotographic photoreceptor. <P>SOLUTION: The electrophotographic photoreceptor is equipped with a conductive substrate, and a photosensitive layer formed via an under coating layer or directly on the conductive substrate, in which a triaryl amine base compound expressed by general formula (1) is incorporated into the photosensitive layer. In the formula, Ar<SP>1</SP>and Ar<SP>2</SP>are the same as or different from each other and denote substituted or unsubstituted 6 to 30C aryl groups; R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>, R<SP>4</SP>and R<SP>5</SP>are the same as or different from each other and denote substituted or unsubstituted 1 to 12C alkyl groups, etc.; (n) denotes an integer from 0 to 3; (p) denotes an integer from 0 to 4; (q) and (r) are the same as or different from each other and denote 0 or 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member and an image forming apparatus using the same.

In recent years, organic photoconductors are the mainstream of electrophotographic photoconductors used in image forming apparatuses such as electrostatic copying machines, facsimile machines, and laser beam printers. This organic photoreceptor has a wide variety of options for the material for forming the photosensitive layer (for example, a charge transport agent, a charge generator, a binder resin, etc.), has a high degree of freedom in functional design, and is easy to manufacture.
In recent years, various studies have been made to improve the electrical characteristics of electrophotographic photoreceptors, and compounds represented by the following general formula (i) or (ii) have been proposed as charge transporting agents having excellent electrical characteristics. (Patent Documents 1 and 2).

(In the formulas (i) and (ii), R ^C1 , R ^C2 , R ^C3 , R ^C4 , R ^C5 and R ^C6 are the same or different from each other, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl, And Ar ^C1 represents a substituted or unsubstituted aryl group.)
However, although the compounds specifically disclosed in Patent Documents 1 and 2 have characteristics such as relatively high charge mobility, the solubility of the coating solution for forming a photosensitive layer in a solvent or a binder resin is known. , Compatibility is not enough. Therefore, when used as a charge transfer agent, the electrical characteristics of the electrophotographic photosensitive member cannot be sufficiently improved.

  In particular, among the compounds represented by the above general formula (i) or (ii), the compound represented by the following formula (a) has poor solubility and compatibility with the solvent and binder resin of the coating solution for forming the photosensitive layer. Patent Document 3 describes that crystallization is observed in part during formation of the photosensitive layer.

  Patent Document 4 proposes a compound represented by the following formula (iii) as a charge transport agent.

(In formula (iii), R ^C7 , R ^C8 , R ^C9 , R ^C10 and R ^C11 are the same or different from each other and represent a lower alkyl group or the like.)
On the other hand, in recent years, due to the demand for downsizing of image forming apparatuses, a so-called static elimination-less system has been adopted in which the static elimination apparatus for an image bearing member such as an electrophotographic photosensitive member is omitted, or the generation of ozone due to corona discharge is prevented. In order to achieve this, it has been attempted to realize charging of the image carrier by a contact charging method.
JP 60-175052 A Japanese Patent Laid-Open No. 62-120346 JP-A-4-57056 JP 7-173112 A

However, all of the compounds specifically disclosed in Patent Document 4 are not sufficiently soluble or compatible with the solvent or binder resin of the photosensitive layer forming coating solution, and the electrical characteristics of the electrophotographic photosensitive member are not sufficient. There is a problem that it drops.
In addition, when the electrophotographic photosensitive member has inferior electrical characteristics, for example, the memory effect of the image bearing member, the occurrence of fogging, etc. are notable by eliminating static elimination or adopting the contact charging method. There is a problem of becoming.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above technical problems and provide an electrophotographic photoreceptor excellent in electrical characteristics.
Another object of the present invention is to provide an image forming apparatus capable of high-quality image forming processing using the electrophotographic photosensitive member.

In order to achieve the above object, the present invention provides:
(1) A conductive substrate and a photosensitive layer formed on the conductive substrate through an undercoat layer or directly, wherein the photosensitive layer is a triaryl represented by the following general formula (1) An electrophotographic photoreceptor containing an amine compound,
General formula (1):

(In the formula (1), Ar ¹ and Ar ² are the same or different from each other, and represent a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and R ¹ and R ² are the same or different from each other, hydrogen An atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, wherein R ³ , R ⁴ and R ⁵ are the same or different from each other; A substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, and an unsaturated group having 2 to 12 carbon atoms An aliphatic hydrocarbon group, a substituted or unsubstituted alkoxy group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, m represents an integer of 0 to 5; n Represents an integer of 0 to 3, p represents an integer of 0 to 4, and q and r are the same or different from each other and represent 0 or 1, provided that m, n and p represent an integer of 2 or more. In addition, different substituents may be substituted on the same benzene ring.)
(2) In the said General formula (1), m has shown the integer of 1-3, The electrophotographic photoreceptor as described in said (1) characterized by the above-mentioned.
(3) In the general formula (1), Ar ¹ and Ar ² are the same substituent, R ¹ and R ² are the same substituent, and q and r are the same. The electrophotographic photosensitive member according to (1) or (2), characterized in that an integer of
(4) Any of the above (1) to (3), wherein the photosensitive layer contains a polycarbonate having any of the repeating units represented by the following general formulas (I) to (III) The electrophotographic photosensitive member according to claim 1,
Formula (I):

    General formula (II):

    Formula (III):

(In the formulas (I) to (III), R ^A , R ^B , R ^C , R ^D , R ^E and R ^F are the same or different and represent a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms. A, b, c, d, e and f are the same or different from each other and represent an integer of 0 to 4.)
(5) The electrophotographic photosensitive member according to any one of (1) to (4), wherein the undercoat layer contains titanium oxide.
(6) The electrophotographic photosensitive member according to any one of (1) to (5), wherein the photosensitive layer is a single layer,
(7) The photosensitive layer is formed on the conductive substrate via an undercoat layer or directly on the surface of the charge generation layer, and is represented by the general formula (1). An electrophotographic photosensitive member according to any one of (1) to (5), comprising a charge transport layer containing a triarylamine-based compound.
(8) An image bearing member, a charging unit for charging the surface of the image bearing member, and the surface of the image bearing member charged by the charging unit are exposed to form an electrostatic latent image on the surface of the image bearing member. An exposure unit for forming the electrostatic latent image, a developing unit for developing the electrostatic latent image as a toner image, and a transfer unit for transferring the toner image from the image carrier to a transfer target to which the toner image is transferred. In the image forming apparatus including the transfer unit, the image carrier is the electrophotographic photosensitive member according to any one of (1) to (7), and charges on the surface of the image carrier are removed. An image forming apparatus, characterized in that it is not provided with a static elimination means for
(9) The image forming apparatus according to (8), wherein the charging unit is a contact charging unit,
Is to provide.

  In the electrophotographic photoreceptor of the present invention, the triarylamine compound represented by the general formula (1) has good solubility and compatibility with the solvent and binder resin of the coating solution for forming the photosensitive layer. In addition, this has couple | bonded with the nitrogen atom of the triarylamine type compound shown by General formula (1), and has group:> C = CH- or group:> C = CH-CH = CH-. A methyl group at the 3-position of at least one of the two benzene rings (the substitution position of the carbon atom bonded to the nitrogen atom of the amine among the carbon atoms forming the benzene ring is the first position). It is presumed to be caused by having

In addition, the triarylamine compound represented by the general formula (1) has a characteristic of high charge mobility.
Therefore, according to the present invention, an electrophotographic photoreceptor excellent in electrical characteristics can be provided by containing the triarylamine compound represented by the general formula (1) in the photosensitive layer.
Further, by using the electrophotographic photosensitive member of the present invention, it is possible to provide an image forming apparatus excellent in image quality even when a static elimination-less system or a contact charging method is adopted.

The electrophotographic photosensitive member of the present invention includes a conductive substrate and a photosensitive layer formed directly on the conductive substrate via an undercoat layer, and the photosensitive layer has the above general formula. The triarylamine compound represented by (1) is contained.
In the triarylamine compound represented by the general formula (1), examples of the substituent represented by Ar ¹ and Ar ¹ include a substituted or unsubstituted aryl group having 6 to 30 carbon atoms.

  Examples of the substituted or unsubstituted aryl group having 6 to 30 carbon atoms include phenyl, naphthyl, biphenylyl, tolyl (o-, m-, p-), xylyl (2,3-, 2,4-, 2, 5-, 3,4-, 3,5-), mesityl, cumenyl (o-, m-, p-), 2-ethyl-6-methylphenyl and the like. Of these, phenyl and p-tolyl are preferable.

  Examples of the group substituted on the aryl group include an alkyl group having 1 to 4 carbon atoms and a halogen atom. Examples of the alkyl group having 1 to 4 carbon atoms include ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and tert-butyl. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, An iodine atom is mentioned.

In the triarylamine compound represented by the general formula (1), the substituent represented by R ¹ and R ² is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or Examples thereof include an unsubstituted aryl group having 6 to 30 carbon atoms. Among these, a hydrogen atom or a substituted or unsubstituted phenyl group is preferable, and a hydrogen atom is more preferable.

  Examples of the substituted or unsubstituted alkyl group having 1 to 12 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, neopentyl, sec-pentyl, tert- Examples include pentyl, hexyl, 1-methylpentyl, 2-methylpentyl, isohexyl, heptyl, 5-methylhexyl, octyl, isooctyl, nonyl, decyl, undecyl, dodecyl and the like. Among these, Preferably, a C1-C4 alkyl group is mentioned, More preferably, a C1-C2 alkyl group is mentioned.

The substituted or unsubstituted aryl group having 6 to 30 carbon atoms is the same as described above.
In the triarylamine compound represented by the general formula (1), the substituent represented by R ³ , R ⁴ and R ⁵ is a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, substituted or unsubstituted. An aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, an unsaturated aliphatic hydrocarbon group having 2 to 12 carbon atoms, a substituted or unsubstituted alkoxy having 1 to 12 carbon atoms Group, or a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms. Of these, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms is preferable.

Examples of the substituted or unsubstituted alkyl group having 1 to 12 carbon atoms and the substituted or unsubstituted aryl group having 6 to 30 carbon atoms are the same as those described above. Among these, Preferably, a C1-C8 alkyl group is mentioned, More preferably, a C1-C4 alkyl group is mentioned.
Examples of the substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms include an aralkyl group having the aryl group exemplified above as an aryl moiety. Examples of the alkylene portion of the substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms include alkylene corresponding to the above-exemplified alkyl groups.

Examples of the unsaturated aliphatic hydrocarbon group having 2 to 12 carbon atoms include vinyl, 1-propenyl, allyl, 2-butenyl, 1,3-butadienyl, isopropenyl and the like.
Examples of the substituted or unsubstituted alkoxy group having 1 to 12 carbon atoms include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, isopentyloxy, neopentyloxy, sec-pentyloxy, tert-pentyloxy, hexyloxy, 1-methylpentyloxy, 2-methylpentyloxy, isohexyloxy, heptyloxy, 5-methylhexyloxy, octyloxy, isooctyloxy, nonyloxy, decyloxy, un Examples include an unsubstituted alkoxy group having 1 to 12 carbon atoms such as decyloxy and dodecyloxy, and the above-mentioned unsubstituted alkoxy group having 1 to 12 carbon atoms substituted with a halogen atom. Examples of the halogen atom include the same halogen atoms as those exemplified above.

  Examples of the substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms include, for example, an unsubstituted aryloxy group having 6 to 30 carbon atoms such as phenoxy and naphthoxy, and the above unsubstituted 6 to 30 carbon atoms. An aryloxy group substituted with a halogen atom is exemplified. Examples of the aryl moiety of the aryloxy group include the aryl groups exemplified above.

M representing the number of substituents ^{R 3} represents an integer of 0 to 5, preferably represents a integer of 1 to 3, more preferably 1 or 2. It is preferable that m is 1 or more, that is, at least one substituent R ³ is provided in order to improve the electrical characteristics of the triarylamine-based compound (1).
When m is 1, the substitution position of the substituent R ³ is preferably the 4-position of the phenyl group (the substitution position of the carbon atom bonded to the nitrogen atom of the amine is the 1-position). When m is 2, the substitution position of the substituent R ³ is preferably the 2-position and 4-position, 3-position and 4-position, or 2-position and 6-position of the phenyl group (bonded to the nitrogen atom of the amine). The substitution position of the carbon atom is the 1st position). In the case where m is 1 or 2, the type of substituent R ³ is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, Preferably, it is methyl or ethyl.

N representing the number of substituents ^{R 4} represents an integer of 0 to 3, preferably represents 0.
P representing the number of substituents ^{R 5} represents an integer of 0 to 4, preferably exhibit 1. When p is 1, the substitution position of the substituent R ⁵ is preferably the 3-position of the phenyl group (the substitution position of the carbon atom bonded to the nitrogen atom of the amine is the 1-position). In the case where p is 1, the type of the substituent R ⁵ is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and particularly preferably. , Methyl. That is, the substituent R ⁵ is preferably symmetric about the nitrogen atom of the amine with respect to the methyl group on the benzene ring that may have the substituent R ⁴ .

In addition, when said m, n, and p show an integer greater than or equal to 2, the same benzene ring may be substituted by a different substituent. That is, for example, when m is 2, the benzene ring having R ³ may be further substituted with two identical substituents. For example, a methyl group and an ethyl group, and a methyl group and Different substituents such as a methoxy group may be substituted.

The triarylamine compound represented by the general formula (1) can be synthesized, for example, according to the methods described in Patent Documents 1, 2, and 4.
The photosensitive layer may further contain other hole transporting agents (excluding the triarylamine compounds represented by the general formula (1)) and various electron transporting agents.
Examples of the other hole transporting agent include N, N, N ′, N′-tetraphenylbenzidine compounds, N, N, N ′, N′-tetraphenylphenylenediamine compounds, N, N, N ', N'-tetraphenylnaphthylenediamine compound, N, N, N', N'-tetraphenylphenanthrylenediamine compound, styryl compound (for example, 9- (4-diethylaminostyryl) anthracene), Oxadiazole compounds (for example, 2,5-di (4-methylaminophenyl) -1,3,4-oxadiazole, etc.), carbazole compounds (for example, polyvinyl carbazole, etc.), pyrazoline compounds (for example, 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline, etc.), organic polysilane compounds, hydrazone compounds, Indian System compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, and triazole compounds. Specific examples of these other hole transporting agents include hole transporting agents described in JP-A Nos. 2004-262813 and 2004-269441.

  Examples of the electron transfer agent include benzoquinone compounds, naphthoquinone compounds, anthraquinone compounds, diphenoquinone compounds, dinaphthoquinone compounds, naphthalene tetracarboxylic acid diimide compounds, fluorenone compounds, malononitrile compounds, thiopyran compounds, tri Examples thereof include nitrothioxanthone compounds, dinitroanthracene compounds, dinitroacridine compounds, nitroantharaquinone compounds, dinitroanthraquinone compounds, and azoquinone compounds. Specific examples of these electron transporting agents include the electron transporting agents described in JP-A No. 2004-262813, JP-A No. 2004-269441, and the like.

The photosensitive layer preferably contains a polycarbonate having any one of the repeating units represented by the above (I) to (III) as a binder resin.
In the repeating units represented by the above (I) to (III), as the substituted or unsubstituted alkyl group having 1 to 12 carbon atoms represented by R ^A , R ^B , R ^C , R ^D , R ^E and R ^F , , The same as described above.

Further, a, b, c, d, e and f indicating the number of substituents R ^{A to} R ^F all represent an integer of 0 to 4, preferably an integer of 0 to 2, more preferably Represents 0 or 1, particularly preferably 0.
The polycarbonate containing the repeating unit represented by the above (I) to (III) alone is a polycarbonate (copolymer) containing the repeating unit represented by the above (I) to (III) and other repeating unit. Merging).

In the case where the polycarbonate is a copolymer containing the repeating units represented by the above (I) to (III) and other repeating units, the other repeating units are not particularly limited and form a polycarbonate. And various repeating units.
In the case where the polycarbonate is a copolymer containing the repeating units represented by the above (I) to (III) and other repeating units, the above (I) to (III) in all the repeating units. ) Is preferably 5 to 100%, more preferably 30 to 100%.

  The binder resin for forming the photosensitive layer is not limited to the above-described polycarbonate. For example, a known resin as the binder resin for forming the photosensitive layer, specifically, polyester, polyarylate, polystyrene, and poly (meth) acrylic. Acid esters and the like can be used. However, among various binder resins, in particular, by using a polycarbonate having any of the repeating units represented by the above (I) to (III), it is represented by the above general formula (1) in the photosensitive layer. While maintaining the compatibility and dispersibility of the triarylamine compound, the durability of the electrophotographic photoreceptor can be improved by improving the mechanical strength, particularly the abrasion resistance, of the photosensitive layer.

  The photosensitive layer may further contain a biphenyl compound. Examples of the biphenyl compound include biphenyl, (o-, m-, p-) terphenyl, 4-biphenyl-phenylmethane; (2-, 3-, 4-) cyclohexylbiphenyl; (2-, 3-, 4-) alkyl biphenyl; (2,6′-, 3,5′-, 4,4 ′-) dialkylbiphenyl and the like. Examples of the alkyl in the biphenyl derivative exemplified above include an unsubstituted alkyl group having 1 to 4 carbon atoms, and examples of the unsubstituted alkyl group having 1 to 4 carbon atoms include those exemplified above.

  The photosensitive layer is blended with a charge generating agent for generating charges. Examples of the charge generator include metal-free phthalocyanine represented by the following formula (CGM-1), titanyl phthalocyanine represented by the following formula (CGM-2), hydroxygallium phthalocyanine represented by the following formula (CGM-3), Phthalocyanine pigments such as chlorogallium phthalocyanine represented by the following formula (CGM-4); disazo pigments, disazo condensation pigments, monoazo pigments, perylene pigments, dithioketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, Examples include squaraine pigments, trisazo pigments, indigo pigments, azurenium pigments, cyanine pigments, pyrylium salts, ansanthrone pigments, triphenylmethane pigments, selenium pigments, toluidine pigments, pyrazoline pigments, and quinacridone pigments. Among them, preferably, phthalocyanine pigments such as metal-free phthalocyanine (CGM-1), titanyl phthalocyanine (CGM-2), hydroxygallium phthalocyanine (CGM-3), chlorogallium phthalocyanine (CGM-4), and the like can be mentioned. Preferably, titanyl phthalocyanine (CGM-2) or hydroxygallium phthalocyanine (CGM-3) is used.

The charge generating agent may be variously selected from those exemplified above so that the electrophotographic photosensitive member has sensitivity in a desired absorption wavelength region. The charge generators exemplified above may be used alone or in combination of two or more.
Currently, semiconductor lasers (LDs) and light emitting diodes (LEDs) are used as exposure light sources in digital optical image forming apparatuses such as laser beam printers, and their wavelengths range from 680 to 830 nm (so-called wavelength range). "Near-infrared region") is the mainstream, so the charge generating agent for electrophotographic photoreceptors used in digital image forming devices is required to have excellent sensitivity in the near-infrared region, Specifically, phthalocyanine pigments are preferably used.

  The crystal form of the phthalocyanine pigment is not particularly limited, and various types can be adopted. Among these, from the viewpoint of further improving the sensitivity of the photoreceptor, X-type or τ-type is used for metal-free phthalocyanine (CGM-1), and α-type is used for titanyl phthalocyanine (CGM-2). In the X-ray diffraction spectrum, when the Bragg angle (2θ ± 0.2 °) is 7.6 ° and 28.6 °, it has a main diffraction peak or Y type (Bragg angle (2θ ± 0.2 °)) It is preferable to use those having a main diffraction peak at 27.2 °, V-type for hydroxygallium phthalocyanine (CGM-3), and II-type for chlorogallium phthalocyanine (CGM-4). In addition, as titanyl phthalocyanine, it is preferable to use what was produced according to the manufacturing method as described in Unexamined-Japanese-Patent No. 2004-145284 and patent 3463032.

For the analog optical image forming apparatus such as an electrostatic copying machine using a white light source such as a halogen lamp, among the charge generators exemplified above, perylene pigments and bisazo pigments having sensitivity in the visible region are suitable. Used for.
In order to improve characteristics such as dispersibility of the charge generating agent in the binder resin, an azo pigment such as disazo yellow, dianisidine orange, pyrazolone orange, or pyrazolone red may be blended.

  Examples of the conductive substrate of the electrophotographic photosensitive member include various materials having conductivity. The conductive substrate may be any material as long as the substrate itself has conductivity or the surface of the substrate has conductivity. Specific examples thereof include, for example, simple metals such as iron, aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, and brass. Examples thereof include a plastic material deposited or laminated, for example, a glass coated with aluminum iodide, tin oxide, indium oxide or the like, for example, a resin substrate in which conductive fine particles such as carbon black are dispersed. The shape of the conductive substrate may be any of a sheet shape and a drum shape according to the structure of the image forming apparatus to be used.

  The conductive substrate may further have a surface subjected to an oxide film treatment or a resin film treatment. The oxide film treatment for the conductive substrate includes, for example, a process of forming an anodic oxide film (anodic oxide film) on the surface of the conductive substrate when aluminum or titanium is used as the conductive substrate. The anodized film is formed by anodizing in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, boric acid, sulfamic acid, etc., and the treatment is performed in sulfuric acid, particularly in the acidic baths exemplified above. Is preferred. The method of anodizing treatment, the method of degreasing treatment performed prior to the anodizing treatment, and the like are not particularly limited, and may be performed according to a conventional method. Examples of the resin coating treatment on the conductive substrate include a treatment in which a polyamide resin, a phenol resin, a melamine resin, an alkyd resin, a polyvinyl acetal resin or the like is dissolved in an appropriate solvent and applied to the surface of the conductive substrate. It is done. As the resin material used for the resin coating treatment, it is particularly preferable to use a polyamide resin or a resol type phenol resin among the resins exemplified above.

In the electrophotographic photoreceptor, an undercoat layer may be formed on a conductive substrate.
In addition, the undercoat layer is formed using a polyamide resin obtained by condensing a dicarboxylic acid component containing a polymerized fatty acid and a diamine component, or formed using an alcohol-soluble copolymerized polyamide resin. Preferably there is.
The polymerized fatty acid is obtained by polymerizing an unsaturated fatty acid. Examples of the unsaturated fatty acid include monobasic unsaturated fatty acids having one or more double bonds or triple bonds. Preferably, for example, oleic acid, linoleic acid, erucic acid and the like have 10 to 10 carbon atoms. 24 monobasic unsaturated fatty acids. Said unsaturated fatty acid may be used independently and may be used in mixture of 2 or more types.

  Commercially available polymerized fatty acids usually contain dimerized fatty acids as the main component, and also contain raw fatty acids that have not been dimerized and trimerized fatty acids. The content ratio of the dimerized fatty acid is preferably 70% or more, more preferably 95% or more. Moreover, it is more preferable that the polymerized fatty acid has a degree of unsaturation reduced by hydrogenation. Specific examples of commercially available polymerized fatty acids include “Buriball 1009” manufactured by Unikema Corporation, “Buriball 1004” manufactured by the same company, “Enball 1010” manufactured by Henkel Corporation, and the like. These commercially available products may be used alone or in combination of two or more.

  Although it does not specifically limit as diamine, Preferably, C2-C20 diamine is mentioned. Specifically, for example, ethylenediamine, 1,4-diaminobutane, hexamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, bis- (4,4 '-Aminocyclohexyl) methane, metaxylylenediamine and the like.

  From the viewpoint of providing solubility in a solvent and flexibility, the polyamide resin may contain a polyamide resin composed of a dicarboxylic acid and a diamine as long as the effects of the present invention are not impaired. It may be a copolymerized polyamide resin comprising a mixture of dicarboxylic acid and diamine. Further, it may be a copolymer with a cyclic monomer such as caprolactam.

Examples of the dicarboxylic acid component other than the polymerized fatty acid include aliphatic dicarboxylic acids such as azelaic acid, sebacic acid, and adipic acid.
The content ratio of the polymerized fatty acid in the polyamide resin obtained by condensing the polymerized fatty acid and the diamine component is preferably 20% or more in the total dicarboxylic acid component containing the polymerized fatty acid.

  Examples of the alcohol-soluble copolymer polyamide resin include those obtained by copolymerization of 6-nylon, 8-nylon, 66-nylon, 12-nylon, 6,10-nylon, and the like. Therefore, a ternary copolymer in which at least three of the above components are copolymerized and a tetracopolymer in which four of the above components are copolymerized are preferable.

More preferably, the undercoat layer contains metal oxide fine particles.
Examples of the metal oxide include titanium oxide, tin oxide, zinc oxide, aluminum oxide, bismuth oxide, cobalt oxide, iron oxide, manganese oxide, yttrium oxide, and indium-tin-oxide (ITO). Of these, titanium oxide and zinc oxide are preferable, and titanium oxide is more preferable.

The particle size of the metal oxide is not particularly limited, but the average particle size (50% particle size) is preferably 2 μm or less so as not to impair the smoothness of the photosensitive layer. In order to maintain the dispersibility in the film, it is preferably 1 μm or less. The average particle diameter (50% particle diameter) of the metal oxide is more preferably 0.005 to 0.1 μm.
In the case where the metal oxide is titanium oxide, the titanium oxide fine particles are preferably subjected to surface treatment from the viewpoint of improving dispersibility in the coating liquid for forming the undercoat layer, for example. . The surface treatment is not particularly limited, and examples thereof include inorganic oxides such as alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), and silica (SiO ₂ ); coating treatment with polysiloxane, stearic acid, and the like.

  Examples of commercially available titanium oxide fine particles include ultrafine particle rutile type titanium oxide STR series (“STR-60C”, “STR-60C-LP”, “STR-60N”, “STR-100C” manufactured by Sakai Chemical Co., Ltd. Ishihara Sangyo Co., Ltd. ultrafine particle titanium oxide TTO series ("TTO-55 (A)", "TTO-55 (C)", "TTO-55 (D)", "TTO-55 ( S) "," TTO-D-1 ", etc.); Ultrafine titanium oxide (" SMT-500SAS "," SMT-100SAS "," MT-500SA "," MT-100SA "," MT-100HD "," MT-05 ", etc.).

  When a layer formed using a polyamide resin obtained by condensing a polymerized fatty acid and a diamine is used as the undercoat layer, a metal oxide (particularly preferably, titanium oxide) is further added to the polyamide resin. When fine particles are blended, the electrical characteristics of the electrophotographic photosensitive member can be stabilized even when the environment of temperature and humidity is changed, and a high-quality image can be formed more stably.

  The electrophotographic photoreceptor may be a single layer type electrophotographic photoreceptor in which the photosensitive layer is a single layer, or a laminated electrophotographic photoreceptor separated into a charge generation layer and a charge transport layer. There may be. Among these, the single-layer type electrophotographic photosensitive member has an advantage that the photosensitive layer can be easily produced, and defects caused by film defects during the lamination process are less likely to occur. In the case of a single layer type electrophotographic photosensitive member, the triarylamine compound represented by the general formula (1) and the electron transporting agent are allowed to coexist in the photosensitive layer, thereby charging the electrophotographic photosensitive member. The polarity can be positively charged. Thereby, the ozone generation amount at the time of the charging process by corona discharge can be reduced.

For obtaining a single layer type electrophotographic photosensitive member, for example, for forming a single layer type photosensitive layer on the surface of a conductive substrate or on the surface of an undercoat layer previously formed on the conductive substrate. The coating liquid may be applied and dried.
The coating solution for forming a single-layer type photosensitive layer includes, for example, the triarylamine compound represented by the above general formula (1), a charge generator, a binder resin, and, if necessary, other examples illustrated above. After compounding a hole transport agent, an electron transport agent, a biphenyl compound, etc., it can be prepared by dispersing and mixing together with a dispersion medium described later using an attritor, a paint shaker, an ultrasonic disperser, or the like.

  When preparing a coating solution for forming a single-layer type photosensitive layer, the amount of the triarylamine compound represented by the general formula (1) is preferably 100 parts by weight of the binder resin in the coating solution. 10 to 200 parts by weight, and more preferably 20 to 100 parts by weight. The blending amount of the charge generating agent is preferably set in the range of 0.1 to 50 parts by weight, more preferably 0.5 to 30 parts by weight with respect to 100 parts by weight of the binder resin in the coating solution. The blending amount of the electron transport agent is preferably set in the range of 5 to 100 parts by weight, more preferably 10 to 80 parts by weight with respect to 100 parts by weight of the binder resin in the coating solution. The amount of the biphenyl compound is preferably set in the range of 1 to 100 parts by weight, more preferably 3 to 30 parts by weight with respect to 100 parts by weight of the binder resin in the coating solution.

The thickness of the single-layer type photosensitive layer is not particularly limited, but is preferably 5 to 100 μm, and more preferably 10 to 50 μm.
On the other hand, in order to obtain a multilayer electrophotographic photosensitive member, for example, a charge generation layer is first formed on the surface of a conductive substrate or on the surface of an undercoat layer previously formed on the conductive substrate. The charge generation layer is formed by applying a coating solution for drying and drying. Next, a charge transport layer forming coating solution is applied to the surface of the charge generation layer thus formed, and dried to form a charge transport layer.

The stacking order of the charge generation layer and the charge transport layer may be the reverse order of the above case, but in general, the charge generation layer is thin and the strength is not sufficient. The stacking order is preferable.
The coating liquid for forming the charge transport layer includes, for example, a triarylamine compound represented by the general formula (1), a binder resin, and, if necessary, other hole transport agents exemplified above and electron transport. After blending an agent, a biphenyl compound and the like, it can be prepared by dispersing and mixing together with a dispersion medium described later using an attritor, a paint shaker, an ultrasonic disperser or the like.

  In preparing the coating solution for forming the charge transport layer, the blending amount of the triarylamine compound represented by the general formula (1) is preferably 20 with respect to 100 parts by weight of the binder resin in the coating solution. It is set in the range of ˜300 parts by weight, more preferably 30 to 200 parts by weight. The amount of the biphenyl compound is preferably set in the range of 1 to 50 parts by weight, more preferably 3 to 30 parts by weight with respect to 100 parts by weight of the binder resin in the coating solution.

Although the thickness of a charge transport layer is not specifically limited, Preferably, it is 5-100 micrometers, More preferably, it is 10-50 micrometers.
On the other hand, a coating solution for forming a charge generation layer can be prepared by, for example, dispersing and mixing a charge generator, a binder resin, and the like and a dispersion medium described later using an attritor, a paint shaker, an ultrasonic disperser, or the like. .

In preparing the coating solution for forming the charge generation layer, the amount of the charge generating agent is preferably 10 to 1000 parts by weight, more preferably 30 to 100 parts by weight with respect to 100 parts by weight of the binder resin in the coating solution. It is set in the range of 500 parts by weight.
The thickness of the charge generation layer is not particularly limited, but is preferably 0.01 to 5 μm, and more preferably 0.1 to 1 μm.

  Examples of the dispersion medium include various organic solvents used in coating solutions for forming a photosensitive layer. Specifically, for example, alcohols such as methanol, ethanol, isopropanol, and butanol, for example, aliphatic hydrocarbons such as n-hexane, octane, and cyclohexane, for example, aromatic hydrocarbons such as benzene, toluene, and xylene Halogenated hydrocarbons such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride, chlorobenzene, for example, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, dioxane, dioxolane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, such as acetone, methyl ethyl ketone Ketones such as cyclohexanone, esters such as ethyl acetate and methyl acetate, such as dimethylformaldehyde, dimethyl Formamide, dimethyl sulfoxide and the like.

  In addition, although not limited to this, tetrahydrofuran, dioxane, dioxolane, cyclohexanone, toluene, xylene, among various organic solvents, in order to stably disperse each component such as a charge transport agent and a binder resin. It is preferable to use at least one organic solvent selected from the group consisting of dichloromethane, dichloroethane and chlorobenzene.

  In addition to the above-mentioned components, the coating solution for forming the photosensitive layer has various conventionally known additives such as an antioxidant, a radical scavenger, a single layer, as long as the electrophotographic characteristics are not adversely affected. Deterioration inhibitors such as term quenchers and ultraviolet absorbers, for example, softeners, plasticizers, surface modifiers, extenders, thickeners, dispersion stabilizers, waxes, acceptors, donors and the like can be blended. Further, a surfactant, a leveling agent or the like may be used in order to improve the dispersibility of the charge transport agent or charge generator and the smoothness of the photosensitive layer surface.

  The undercoat layer is, for example, a polyamide resin obtained by condensing a dicarboxylic acid component containing a polymerized fatty acid and a diamine component, or an alcohol-soluble copolymerized polyamide resin, if necessary, together with metal oxide fine particles, which will be described later. It can be formed by dispersing or dissolving in a dispersion medium, and then applying the coating solution for forming the undercoat layer thus obtained on a conductive substrate and drying.

Examples of the dispersion medium for the undercoat layer include, but are not limited to, for example, alcohols having 1 to 4 carbon atoms such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, benzene, toluene, ( and a mixed solvent with an aromatic hydrocarbon having 6 to 12 carbon atoms such as o, m, p-) xylene.
The undercoat layer-forming coating solution can be prepared, for example, by dispersing and mixing the above components using a roll mill, ball mill, attritor, paint shaker, ultrasonic disperser, or the like.

Although the thickness of an undercoat layer is not specifically limited, Preferably, it is 0.001-50 micrometers, More preferably, it is 0.1-10 micrometers.
Although not particularly limited in the present invention, a protective layer is provided on the surface of the photosensitive layer or the surface of the charge generation layer and the charge transport layer formed on the outer surface side of the photoreceptor. It may be formed.

  The electrophotographic photoreceptor of the present invention, for example, exposes the image carrier, a charging unit for charging the surface of the image carrier, the surface of the image carrier charged by the charging unit, and the image An exposure means for forming an electrostatic latent image on the surface of the carrier, a developing means for developing the electrostatic latent image as a toner image, and the image carrier to the transfer target to which the toner image is transferred. An image forming apparatus comprising: a transfer unit for transferring the toner image; and no discharger for removing charges on the surface of the image carrier. In an image forming apparatus employing the system, it is preferably used as the image carrier.

The charging means, exposure means, development means and transfer means are not particularly limited, and various known charging means, exposure means, development means and transfer means can be employed.
According to the electrophotographic photosensitive member of the present invention, the generation of exposure memory can be sufficiently suppressed even when used as an image carrier in an image forming apparatus employing the above-described static elimination-less system. The occurrence of memory effects on the body is reduced to a level that cannot be recognized on the image.

In the image forming apparatus, the charging unit is preferably a contact charging unit.
Examples of the contact charging means include a charging roller and a charging brush.
According to the image forming apparatus employing the contact charging method, when the electrophotographic photosensitive member of the present invention is used as the image carrier, a good image free from fogging can be obtained.

Next, although this invention is demonstrated based on an Example and a comparative example, this invention is not limited by the following Example.
Production Example 1
Titanyl phthalocyanine was synthesized according to the method described in JP-A No. 2004-145284. First, 25 g of o-phthalonitrile, 28 g of titanium tetrabutoxide, and 300 g of quinoline were added to a flask purged with argon, and the temperature was raised to 150 ° C. while stirring. Next, while evaporating the vapor generated from the reaction system, the temperature was raised to 215 ° C. while maintaining this temperature, and the reaction was continued for another 2 hours while stirring. After completion of the reaction, when the reaction mixture is cooled to 150 ° C., the reaction mixture is filtered off with a glass filter, and the resulting solid is washed successively with N, N-dimethylformamide and methanol and dried in vacuo to obtain 24 g of a blue-purple solid. It was. (Pigmentation pretreatment)
10 g of the blue-violet solid obtained by the above-mentioned pigmentation pretreatment was added to 100 mL of N, N-dimethylformamide, heated to 130 ° C. with stirring, and stirred for 2 hours. Next, heating was stopped when 2 hours passed, and after cooling to 23 ± 1 ° C., stirring was also stopped, and the liquid was allowed to stand for 12 hours in this state (stabilization treatment).

And the liquid stabilized by the said stabilization process was filter-separated with the glass filter, the obtained solid was wash | cleaned with methanol, and then it vacuum-dried, and 9.83 g of crude crystals of the titanyl phthalocyanine compound were obtained.
Next, 5 g of crude crystals of titanyl phthalocyanine are dissolved in 100 mL of concentrated sulfuric acid, and this sulfuric acid solution is added dropwise to water under ice cooling, followed by stirring at room temperature for 15 minutes, and further at around 23 ± 1 ° C. for 30 minutes. It was allowed to stand and recrystallized. Further, after separating the crystals with a glass filter and washing with water until the washing solution becomes neutral, the crystals are not dried and dispersed in 200 mL of chlorobenzene in the presence of water and heated to 50 ° C. Stir for 10 hours.

And after filtering a liquid with a glass filter, the obtained solid was vacuum-dried at 50 degreeC for 5 hours, and 4.1g of crystals (blue powder) of titanyl phthalocyanine were obtained.
This titanyl phthalocyanine is represented by the above formula (CGM-2) and has a Bragg angle (2θ ± 0.2 °) of 7.4 immediately after synthesis and after immersion in 1,3-dioxolane or tetrahydrofuran for 7 days. It has no diffraction peak in X-ray diffraction analysis when it is at 0 ° and 26.2 °, and there is a difference between 50 ° C. and 400 ° C. except for a peak around 90 ° C. accompanying vaporization of adsorbed water. It was confirmed that there was no endothermic peak in the scanning calorimetric analysis.

<Manufacture of laminated electrophotographic photoreceptor>
Example 1
Titanium oxide (Taca Co., Ltd., prototype SMT-02, number average primary particle size 10 nm) 2 weight after surface treatment with alumina and silica and surface treatment with methyl hydrogen polysiloxane under wet dispersion Parts, 6,12,66,610-quaternary copolymerized polyamide resin (trade name “Amilan (registered trademark) CM8000”, manufactured by Toray Industries, Inc.), 10 parts by weight of methanol, and 2 parts by weight of butanol Was mixed with a bead mill for 5 hours to prepare an undercoat layer coating solution.

The undercoat layer coating solution is filtered through a filter having an opening of 5 μm, and then applied to the surface of an aluminum drum-shaped support (diameter 30 mm, total length 238.5 mm) as a conductive support by a dip coating method. Applied. After coating, the film was heat treated at 130 ° C. for 30 minutes to form an undercoat layer having a thickness of 2 μm.
Next, as a charge generator, 1 part by weight of titanyl phthalocyanine (CGM-2) obtained in Preparation Example 1 above, and as a binder resin, a polyvinyl acetal resin (trade name “ESREC KS-5”, Sekisui Chemical Co., Ltd.) )) 0.5 part by weight, 0.5 part by weight of phenoxy resin (manufactured by PKKH InChem), 40 parts by weight of propylene glycol monomethyl ether and 40 parts by weight of tetrahydrofuran as a dispersion medium were blended, and 2 hours in a bead mill Dispersed to prepare a coating solution for the charge generation layer.

The obtained coating solution for charge generation layer was filtered through a filter having a mesh opening of 3 μm, and then applied onto the undercoat layer by the dip coating method. After coating, the film was dried at 50 ° C. for 5 minutes to form a charge generation layer having a thickness of 0.3 μm.
Furthermore, as a hole transport agent, 70 parts by weight of a triarylamine compound represented by the following formula (1-1), as an additive, 10 parts by weight of m-terphenyl, and as a binder resin, the following formula (RU— By blending 100 parts by weight of a polycarbonate resin (Resin-1, viscosity average molecular weight 30500) consisting of the repeating unit represented by 1) and 600 parts by weight of tetrahydrofuran as a solvent, the mixture is stirred and dissolved to be used for a charge transport layer. A coating solution was prepared.

  Further, the obtained charge transport layer coating solution is applied onto the above charge generation layer and dried at 130 ° C. for 30 minutes to form a charge transport layer having a thickness of 20 μm, thereby obtaining a laminated electrophotographic film. A photoreceptor was obtained.

Example 2
Instead of 70 parts by weight of the triarylamine compound represented by the above formula (1-1), 70 parts by weight of the triarylamine compound represented by the following formula (1-2) was used as the hole transport agent. A laminated electrophotographic photosensitive member was obtained in the same manner as Example 1 except for the above.

Example 3
Instead of 70 parts by weight of the triarylamine compound represented by the above formula (1-1), 70 parts by weight of the triarylamine compound represented by the following formula (1-3) was used as the hole transport agent. A laminated electrophotographic photosensitive member was obtained in the same manner as Example 1 except for the above.

Example 4
Instead of 70 parts by weight of the triarylamine compound represented by the above formula (1-1), 70 parts by weight of the triarylamine compound represented by the following formula (1-4) was used as the hole transport agent. A laminated electrophotographic photosensitive member was obtained in the same manner as Example 1 except for the above.

Example 5
Instead of 70 parts by weight of the triarylamine compound represented by the above formula (1-1), 70 parts by weight of the triarylamine compound represented by the following formula (1-5) was used as the hole transport agent. A laminated electrophotographic photosensitive member was obtained in the same manner as Example 1 except for the above.

Example 6
Example 1 except that 1 part by weight of a hydroxygallium phthalocyanine represented by the above formula (CGM-3) was used in place of 1 part by weight of a titanyl phthalocyanine represented by the above formula (CGM-2) as a charge generating agent. In the same manner as above, a multilayer electrophotographic photosensitive member was obtained.
Example 7
Instead of 100 parts by weight of the polycarbonate resin (Resin-1) consisting of the repeating unit represented by the above formula (RU-1) as the binder resin, the polycarbonate resin (Resin) consisting of the repeating unit represented by the following formula (RU-2) -2, viscosity average molecular weight 31000) A laminated electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that 100 parts by weight were used.

Example 8
Instead of 100 parts by weight of the polycarbonate resin (Resin-1), 100 parts by weight of a polycarbonate resin (Resin-3, viscosity average molecular weight 32500) composed of a repeating unit represented by the following formula (RU-3) was used as the binder resin. A laminated electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that.

Example 9
As the binder resin, instead of 100 parts by weight of the polycarbonate resin (Resin-1), a repeating unit represented by the following formula (RU-4) and a repeating unit represented by the following formula (RU-2) are sequentially added: A laminated electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that 100 parts by weight of polycarbonate resin (Resin-4, viscosity average molecular weight 29800) contained at a ratio of 85 (molar ratio) was used.

Example 10
As the binder resin, instead of 100 parts by weight of the polycarbonate resin (Resin-1), a repeating unit represented by the following formula (RU-5) and a repeating unit represented by the following formula (RU-2) are sequentially added: A laminated electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that 100 parts by weight of polycarbonate resin (Resin-5, viscosity average molecular weight 31000) contained at a ratio of 85 (molar ratio) was used.

Example 11
As the binder resin, instead of 100 parts by weight of the polycarbonate resin (Resin-1), a repeating unit represented by the following formula (RU-6) and a repeating unit represented by the following formula (RU-2) are sequentially added: A laminated electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that 100 parts by weight of polycarbonate resin (Resin-6, viscosity average molecular weight 31000) contained at a ratio of 85 (molar ratio) was used.

Example 12
As a binder resin, instead of 100 parts by weight of polycarbonate resin (Resin-1), a mixture (total amount of 100 parts by weight) of 70 parts by weight of polycarbonate resin (Resin-3) and 30 parts by weight of polycarbonate resin (Resin-4) is used. A laminated electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that it was used.

Example 13
As a binder resin, instead of 100 parts by weight of polycarbonate resin (Resin-1), a mixture (total amount of 100 parts by weight) of 70 parts by weight of polycarbonate resin (Resin-3) and 30 parts by weight of polycarbonate resin (Resin-5) is used. A laminated electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that it was used.

Example 14
As a binder resin, instead of 100 parts by weight of polycarbonate resin (Resin-1), a mixture (total amount of 100 parts by weight) of 70 parts by weight of polycarbonate resin (Resin-3) and 30 parts by weight of polycarbonate resin (Resin-6) is used. A laminated electrophotographic photosensitive member was obtained in the same manner as in Example 1 except that it was used.

Comparative Example 1
Instead of 70 parts by weight of the triarylamine compound represented by the above formula (1-1), 70 parts by weight of the triarylamine compound represented by the following formula (c-1) was used as the hole transport agent. A laminated electrophotographic photosensitive member was obtained in the same manner as Example 1 except for the above.

Comparative Example 2
Instead of 70 parts by weight of the triarylamine compound represented by the above formula (1-1), 70 parts by weight of the triarylamine compound represented by the following formula (c-2) was used as the hole transport agent. A laminated electrophotographic photosensitive member was obtained in the same manner as Example 1 except for the above.

Comparative Example 3
Instead of 70 parts by weight of the triarylamine compound represented by the above formula (1-1), 70 parts by weight of the triarylamine compound represented by the following formula (c-3) was used as the hole transport agent. A laminated electrophotographic photosensitive member was obtained in the same manner as Example 1 except for the above.

<Performance evaluation of multilayer electrophotographic photoreceptor>
The laminated electrophotographic photoreceptors obtained in Examples 1 to 14 and Comparative Examples 1 to 3 were obtained by using a commercially available printer (trade name “MicroLine-22N” manufactured by Oki Data Co., Ltd.) employing a negative charge reversal development process. ) As a photosensitive drum. This printer did not have a static elimination means, and was a contact charging type.

Next, using this printer, room temperature (23 ° C.), humidity 50% RH, normal temperature and humidity (hereinafter referred to as “N / N environment”), and 35 ° C./85% RH, high temperature and high humidity environment. (Hereinafter, referred to as “H / H environment”), each of the black solid images was processed continuously for 100,000 sheets, and the electrical characteristics under the N / N environment and under the H / H environment. The fog density was evaluated.
The electrical characteristics were evaluated by comparing the residual potential V _L (V) at the black solid portion potential at the development position and the blank paper potential V ₀ (V) at the blank paper portion after image formation processing for 100,000 sheets continuously. This was done by measuring. The smaller the absolute value of the residual potential _VL, the better the sensitivity.

  Note that the blank area refers to the surface of the photosensitive drum that has been charged, exposed, developed, and transferred one cycle before the image forming process (a process comprising a cycle of charging, exposure, development, and transfer). The part that was not done. That is, in the performance evaluation for performing the image formation processing of the black solid image, the portion of the image forming area (the area where the charging process is performed) on the surface of the photosensitive drum where the exposure and the development of the black solid image are not performed. pointing.

Also, a solid black image is formed one cycle before the image forming process (one cycle before the photosensitive drum) with respect to the blank paper potential V ₀ (V) after the 100,000 sheets of continuous image forming processing. After that, the potential of the blank paper was V _0b (V), and the value represented by the formula: V ₀ -V _0b (V) was the exposure memory. The smaller the value of V ₀ −V _0b (V), the smaller the exposure memory.

In addition, the fog density was evaluated by measuring the fog density on a blank paper portion using an image densitometer (model number “RD-19I”, manufactured by Gretab Macbeth Co., Ltd.) after performing image formation processing continuously for 100,000 sheets. did.
The results of the performance evaluation are shown in Table 1.

As shown in Table 1, the laminated electrophotographic photoreceptors of Examples 1 to 14 had good electrical characteristics and suppressed fog density.
On the other hand, in Comparative Examples 1 and 2, the solubility of the hole transport agent in the coating solution and the compatibility with the binder resin are poor, and after formation of the charge transport layer, crystals of the hole transport agent are formed on the entire surface of the photosensitive drum. Precipitated. For this reason, evaluation of sensitivity characteristics and image formation processing cannot be performed.

In Comparative Example 3, the solubility of the hole transport agent in the coating solution and the compatibility with the binder resin were low, and the electrical characteristics of the multilayer electrophotographic photosensitive member were inferior to those of Examples 1-14. In addition, crystallization of the hole transport agent was observed in the charge transport layer.
<Manufacture of single layer type electrophotographic photoreceptor>
Example 15
The same coating solution for the undercoat layer as prepared in Example 1 was filtered with a filter having an opening of 5 μm, and then the surface of an aluminum drum-shaped support (diameter 30 mm, total length 238.5 mm) as a conductive support. The dip coating method was applied. After coating, the film was heat treated at 130 ° C. for 30 minutes to form an undercoat layer having a thickness of 2 μm.

  Next, 3 parts by weight of an X-type metal-free phthalocyanine represented by the above formula (CGM-1) as a charge generating agent, and a triarylamine compound 50 represented by the above formula (1-1) as a hole transporting agent. Polycarbonate resin (Resin-) consisting of 40 parts by weight of an azoquinone compound represented by the following formula (ETM-1) as an electron transporting agent, and a repeating unit represented by the above formula (RU-1) as a binder resin. 1) 100 parts by weight and 600 parts by weight of tetrahydrofuran as a dispersion medium were blended and mixed and dispersed by an ultrasonic disperser to prepare a coating solution for forming a photosensitive layer.

  Next, the obtained coating solution is filtered through a 3 μm filter, and then applied by the dip coating method on the subbing layer produced above, and dried with hot air at 130 ° C. for 40 minutes to form a photosensitive layer having a thickness of 25 μm. To obtain a single layer type electrophotographic photosensitive member.

Example 16
Instead of 50 parts by weight of the triarylamine compound represented by the above formula (1-1), 50 parts by weight of the triarylamine compound represented by the above formula (1-2) was used as the hole transport agent. A single-layer electrophotographic photosensitive member was obtained in the same manner as Example 15 except for the above.
Example 17
Instead of 50 parts by weight of the triarylamine compound represented by the above formula (1-1), 50 parts by weight of the triarylamine compound represented by the above formula (1-3) was used as the hole transport agent. A single-layer electrophotographic photosensitive member was obtained in the same manner as Example 15 except for the above.

Example 18
Instead of 50 parts by weight of the triarylamine compound represented by the above formula (1-1), 50 parts by weight of the triarylamine compound represented by the above formula (1-4) was used as the hole transport agent. A single-layer electrophotographic photosensitive member was obtained in the same manner as Example 15 except for the above.
Example 19
Instead of 50 parts by weight of the triarylamine compound represented by the above formula (1-1), 50 parts by weight of the triarylamine compound represented by the above formula (1-5) was used as the hole transport agent. A single-layer electrophotographic photosensitive member was obtained in the same manner as Example 15 except for the above.

Example 20
Example except that 40 parts by weight of a naphthoquinone compound represented by the following formula (ETM-2) was used instead of 40 parts by weight of a quinone compound represented by the above formula (ETM-1) as an electron transport agent. In the same manner as in Example 15, a single layer type electrophotographic photosensitive member was obtained.

Example 21
Example except that 40 parts by weight of a naphthoquinone compound represented by the following formula (ETM-3) was used instead of 40 parts by weight of a quinone compound represented by the above formula (ETM-1) as an electron transport agent. In the same manner as in Example 15, a single layer type electrophotographic photosensitive member was obtained.

Example 22
Except for using 40 parts by weight of a diphenoquinone compound represented by the following formula (ETM-4) instead of 40 parts by weight of a quinone compound represented by the above formula (ETM-1) as an electron transporting agent. In the same manner as in Example 15, a single layer type electrophotographic photosensitive member was obtained.

Example 23
Implementation was carried out except that 40 parts by weight of a dinaphthoquinone compound represented by the following formula (ETM-5) was used in place of 40 parts by weight of the quinone compound represented by the above formula (ETM-1) as an electron transport agent. In the same manner as in Example 15, a single layer type electrophotographic photosensitive member was obtained.

(In formula (ETM-5), t-Pe represents a tert-pentyl group.)
Example 24
In place of 3 parts by weight of the X-type metal-free phthalocyanine represented by the above formula (CGM-1) as a charge generator, 3 parts by weight of titanyl phthalocyanine (CGM-2) obtained in Preparation Example 1 was used. As an auxiliary pigment, C.I. I. A single-layer electrophotographic photosensitive member was obtained in the same manner as in Example 15 except that 2 parts by weight of Pigment Yellow 93 was blended.

Example 25
Other than using 3 parts by weight of V-type hydroxygallium phthalocyanine represented by the above formula (CGM-3) instead of 3 parts by weight of X-type metal-free phthalocyanine represented by the above formula (CGM-1) as the charge generating agent Produced a single-layer electrophotographic photosensitive member in the same manner as in Example 15.
Example 26
Other than using 3 parts by weight of type II chlorogallium phthalocyanine represented by the above formula (CGM-4) instead of 3 parts by weight of X type metal-free phthalocyanine represented by the above formula (CGM-1) as the charge generating agent Produced a single-layer electrophotographic photosensitive member in the same manner as in Example 15.

Example 27
Implementation was performed except that 100 parts by weight of polycarbonate resin (Resin-3) represented by the above formula (RU-3) was used as the binder resin instead of 100 parts by weight of polycarbonate resin (Resin-1). In the same manner as in Example 15, a single layer type electrophotographic photosensitive member was obtained.

Example 28
As the binder resin, instead of 100 parts by weight of the polycarbonate resin (Resin-1), a repeating unit represented by the above formula (RU-6) and a repeating unit represented by the above formula (RU-2) are sequentially added: A single-layer electrophotographic photosensitive member was obtained in the same manner as in Example 15 except that 100 parts by weight of polycarbonate resin (Resin-6) contained at a ratio of 85 (molar ratio) was used.

<Performance evaluation of single layer type electrophotographic photoreceptor>
The single layer type electrophotographic photosensitive member obtained in Examples 15 to 28 was mounted as a photosensitive drum in a laser beam printer (trade name “DP-560” manufactured by Kyocera Mita Co., Ltd.). Note that the static elimination lamp for neutralizing the photosensitive drum was removed. The rotational speed of the photosensitive drum was 60 mm / sec, and the exposure light quantity was 1.0 μJ / cm ² . The charging means of this printer was a scorotron charging system.

Next, using this printer, 100,000 black images were continuously formed in an N / N environment and an H / H environment, respectively, and the electrical characteristics in the N / N environment The fog density in an H / H environment was evaluated.
The evaluation of the electrical characteristics is based on the residual potential V _L (V) corresponding to the black solid portion potential at the developing position and the blank paper potential V ₀ (corresponding to the blank paper portion) after the image formation processing for 100,000 sheets continuously. And V). The smaller the absolute value of the residual potential _VL, the better the sensitivity.

Further, the exposure memory was measured in the same manner as in the case of the multilayer photoreceptor.
In addition, the fog density was evaluated by measuring the fog density on a blank paper portion using an image densitometer (model number “RD-19I”, manufactured by Gretab Macbeth Co., Ltd.) after performing image formation processing continuously for 100,000 sheets. did.
The results of the above performance evaluation are shown in Table 2.

As shown in Table 2, the single layer type electrophotographic photoreceptors of Examples 15 to 28 had good electrical characteristics and suppressed fog density.
The present invention is not limited to the above description, and various design changes can be made within the scope of the matters described in the claims.

Claims (9)

A conductive substrate, and a photosensitive layer formed directly on the conductive substrate via an undercoat layer, or
The electrophotographic photoreceptor, wherein the photosensitive layer contains a triarylamine compound represented by the following general formula (1).
General formula (1):

(In the formula (1), Ar ¹ and Ar ² are the same or different from each other, and represent a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and R ¹ and R ² are the same or different from each other, hydrogen An atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, wherein R ³ , R ⁴ and R ⁵ are the same or different from each other; A substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms, and an unsaturated group having 2 to 12 carbon atoms An aliphatic hydrocarbon group, a substituted or unsubstituted alkoxy group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, m represents an integer of 0 to 5; n Represents an integer of 0 to 3, p represents an integer of 0 to 4, and q and r are the same or different from each other and represent 0 or 1, provided that m, n and p represent an integer of 2 or more. In addition, different substituents may be substituted on the same benzene ring.)   The electrophotographic photosensitive member according to claim 1, wherein in the general formula (1), m represents an integer of 1 to 3. In the general formula (1), Ar ¹ and Ar ² are the same substituent, R ¹ and R ² are the same substituent, and q and r are the same integer. The electrophotographic photosensitive member according to claim 1, wherein the electrophotographic photosensitive member is shown. The electrophotographic film according to claim 1, wherein the photosensitive layer contains a polycarbonate having any one of repeating units represented by the following general formulas (I) to (III). Photoconductor.
Formula (I):

General formula (II):

Formula (III):

(In the formulas (I) to (III), R ^A , R ^B , R ^C , R ^D , R ^E and R ^F are the same or different and represent a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms. A, b, c, d, e and f are the same or different from each other and represent an integer of 0 to 4.)   The electrophotographic photosensitive member according to claim 1, wherein the undercoat layer contains titanium oxide.   The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer is a single layer.   The photosensitive layer is formed on the conductive substrate via an undercoat layer or directly, and the triaryl represented by the general formula (1) is formed on the surface of the charge generation layer. An electrophotographic photoreceptor according to claim 1, comprising a charge transport layer containing an amine compound. An image carrier;
Charging means for charging the surface of the image carrier;
Exposure means for exposing the surface of the image carrier charged by the charging means to form an electrostatic latent image on the surface of the image carrier;
Developing means for developing the electrostatic latent image as a toner image;
Transfer means for transferring the toner image from the image carrier to a transfer target to which the toner image is transferred;
In an image forming apparatus comprising:
The image carrier is the electrophotographic photosensitive member according to any one of claims 1 to 7, and
An image forming apparatus, wherein a charge eliminating unit for removing charges on the surface of the image carrier is not provided.   The image forming apparatus according to claim 8, wherein the charging unit is a contact charging unit.