JP2591648B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor using two kinds of charge generating substances.

[Background of the Invention] With the recent increase in speed and miniaturization of electrophotographic copying machines, higher sensitivity of electrophotographic photosensitive members used for the electrophotographic copying machines has been increasingly required. Electrophotographic photoreceptors are becoming mainstream.

Azo pigments conventionally used as charge generating materials for the above-mentioned function-separated type electrophotographic photoreceptors, particularly bisazo pigments (for example, JP-A-47-3754, JP-A-53-133445, JP-A-58-70)
Nos. 232 and 58-140745) have good sensitivity on the long wavelength side of 570 nm or more and are relatively high as a whole. However, when such an azo pigment is used as a charge generating substance, its charge transport ability is low, and in order to take advantage of long-wavelength sensitivity, it is necessary to form the charge generating layer with a thin film of about 0.1 to 0.3 μm. There is. When the film thickness is increased, the charging ability and sensitivity are insufficient, and the repetition characteristics are deteriorated. When such a thin film is applied by a dip coating method, which is a general manufacturing method, coating defects such as unevenness in a step, liquid dripping, and aggregation are easily generated, leading to a reduction in coating yield, a reduction in productivity, and an increase in cost.

Phthalocyanine pigments are also known as charge generating substances (Japanese Patent Publication No. 49-4338, Japanese Patent Application Laid-Open No. 58-182639).
And Nos. 60-19154) have the same problems as the above-mentioned azo pigments.

On the other hand, polycyclic quinone pigments are known as pigments having good image reproducibility in copying (see JP-A-57-67933). Polycyclic quinone pigments generally have a higher charge transporting function than bisazo pigments, and when used in a relatively thick charge generating layer, usually of the order of 0.5 to 3 μm, provide a photoreceptor with good electrophotographic properties. Therefore, since a relatively thick film can be formed, coating defects during manufacturing hardly occur. However, when this polycyclic quinone pigment is used, the sensitivity is significantly reduced in the region of 570 nm or more, and has almost no sensitivity in the region around 580 to 620 nm. The sensitivity is insufficient for use in small copiers.

[Object of the Invention] The present invention has been made in view of the above-mentioned conventional problems. First, the present invention has sufficient sensitivity even when used in a high-speed copying machine or a small-sized copying machine, and causes coating defects during manufacturing. It is another object of the present invention to provide an electrophotographic photoreceptor that is difficult to produce and is excellent in productivity, and secondly, to provide a high-sensitivity electrophotographic photoreceptor excellent in repetition characteristics.

[Constitution of the Invention] The object of the present invention is to provide an electrophotographic photoreceptor having at least a charge generation layer and a charge transport layer on a conductive support, wherein the charge generation layer has the following general formula [I] , [II], [III], [IV], [V], [VI] or [VII], at least one selected from bisazo compounds, metal-free phthalocyanine compounds and metal phthalocyanine compounds, and a polycyclic quinone compound The film containing at least one compound and having the same thickness as the charge generation layer is
It is achieved by an electrophotographic photoreceptor characterized in that the thickness is 0.5 μm to 5 μm.

The bisazo compound used in the present invention is represented, for example, by the general formula BN = NA) ₂ . Here, A represents a coupler, and B represents a divalent organic group in which the azo group-bonded carbon atoms form a conjugated double bond system. Specifically, for example, compounds represented by the following general formulas [I] to [VII] are mentioned as typical ones.

General formula [I] In the formula, Ar ₁ , Ar ₂ and Ar ₃ each represent a substituted or unsubstituted aromatic carbocyclic residue or a substituted or unsubstituted aromatic heterocyclic residue. R ₁ , R ₂ , R ₃ and R ₄ each represent a hydrogen atom or an electron-withdrawing group. However, at least one of R _{1 to} R ₄ is an electro withdrawing group.

A ₁ Represents

Where X ₁ is a hydroxy group, Or -NHSO ₂ -R ₈ (where R ₆ and R ₇ each represent a hydrogen atom or a substituted or unsubstituted alkyl group, and R ₈ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. Represents). Y ₁ represents a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted sulfamoyl group, a carboxyl group or a sulfo group. Z ₁ represents an atomic group necessary for constituting a substituted or unsubstituted carbocyclic aromatic ring or a substituted or unsubstituted heterocyclic aromatic ring. R ₅ represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted carbamoyl group, a carboxyl group or an ester group thereof.
A 'represents a substituted or unsubstituted aryl group. n is
M represents an integer of 1, 2 or 3, and m represents an integer of 0, 1 or 2.

In the general formula [I], the residue represented by Ar ₁ , Ar ₂ or Ar ₃ is, for example, And when the ring has a substituent, examples of the substituent include a halogen atom and an alkyl group.

The electron-withdrawing group represented by R ₁ , R ₂ , R ₃ or R ₄ is, for example, a halogen atom (a chlorine atom, a bromine atom, etc.), a cyano group, a nitro group and the like.

Representative specific examples of the compound represented by the general formula [I] are shown below, but it should not be construed that the invention is limited thereto.

General formula [II] Where A ₂ is Represents

Here, Ar ₄ represents an aromatic group or a heterocyclic group. Ar ₅ and Ar ₆ each represent an aromatic ring group. R ₉ and R ₁₁ each represent a hydrogen atom, an alkyl group or an aryl group. R
₁₀ represents an alkyl group, a carboxyl group or an ester group thereof. Z ₂ represents an atom group necessary for forming an aromatic ring or a heterocyclic ring.

The aromatic ring group represented by Ar ₄ , Ar ₅ or Ar ₆ is, for example, a phenyl group, a naphthyl group or the like, and the heterocyclic group represented by Ar ₄ is, for example, a dibenzofuran ring, a carbazole ring, an indazole ring or the like. The alkyl group represented by R ₉ , R ₁₀ or R ₁₁ is, for example, a lower alkyl group such as a methyl group or an ethyl group, and the aryl group represented by R ₉ or R ₁₁ is, for example, a phenyl group. Specific examples of the aromatic ring or heterocyclic ring formed by Z ₂ are the same as the specific examples of Ar _{4 to} Ar ₆ described above.

Each group represented by Ar _{4 to} Ar ₆ , R _{9 to} R ₁₁ and Z ₂ may have a substituent, and examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, a nitro group, and a substituted amino group. , An acylamino group, a cyano group, a carboxyl group, a sulfonic acid group, a sulfamoyl group and the like.

Representative specific examples of the compound represented by the general formula [II] are shown below, but it should not be construed that the invention is limited thereto.

General formula [III] Wherein, A ₂ has the same meaning as A ₂ in the general formula [II].

Representative specific examples of the compound represented by the general formula [III] are shown below, but it should not be construed that the invention is limited thereto.

General formula [IV] In the formula, R ₁₂ and R ₁₃ each represent a hydrogen atom, a halogen atom or an alkyl group. X ₂ is -O- or (R ₁₄ represents a hydrogen atom, an alkyl group or an aryl group.)

Represents Z ₃ represents an arylene group. R ₁₅ represents an alkyl group or an aryl group. R ₁₆ represents a hydrogen atom, an alkyl group or an aryl group. Ar ₇ represents an aryl group. Y ₂ represents an atom group necessary to form an aromatic carbocyclic or heterocyclic ring.

Examples of the alkyl group represented by R _{12 to} R ₁₆ include a methyl group and an ethyl group, and examples of the aryl group represented by R _{14 to} R ₁₆ and Ar ₇ include a phenyl group and a naphthyl group. May have a substituent.

X ₂ is particularly preferably —O—.

Examples of the arylene group represented by Z ₃ include a phenylene group and a naphthylene group, and these groups may have a substituent. Examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, a nitro group, a hydroxyl group and the like. Z ₃ is particularly preferably a substituted or unsubstituted phenylene group.

The aromatic carbocyclic or heterocyclic ring formed by Y ₂ is, for example, a benzene ring, a naphthalene ring, a triazole ring and the like.

Representative specific examples of the compound represented by the general formula [IV] are shown below, but it should not be construed that the invention is limited thereto.

General formula [V] In the formula, Ar ₈ and Ar ₉ each represent a substituted or unsubstituted aromatic carbocyclic residue or a substituted or unsubstituted aromatic hetero residue. R ₁₇ and R ₁₈ each represent a hydrogen atom or an electron-withdrawing group. However, at least one of R ₁₇ and R ₁₈ is an electron-withdrawing group.

A ₄ Represents

Here, X ₃ is a hydroxy group, , Is -NHSO ₂ -R ₂₂ (represented here R ₂₀ and R ₂₁ are each a hydrogen atom or a substituted or unsubstituted alkyl group, R ₂₂
Represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. ). Y ₃ is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group,
A substituted or unsubstituted alkoxy group, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted sulfamoyl group, a carboxy group, an ester group thereof, or a sulfo group. Z ₄ represents an atomic group necessary for constituting a substituted or unsubstituted carbocyclic aromatic ring or a substituted or unsubstituted heterocyclic aromatic ring. R ₁₉ represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted carbamoyl group, a carboxyl group or an ester group thereof. A ″ represents a substituted or unsubstituted aryl group, n represents an integer of 1, 2 or 3, and m represents an integer of 0, 1 or 2.

In the general formula [V], as the residue represented by Ar ₈ or Ar ₉ , for example, When a substituent is present on the ring, examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, and a cyano group.

Examples of the electron-withdrawing group represented by R ₁₇ or R ₁₈ include a halogen atom (a chlorine atom, a bromine atom, etc.), a cyano group,
A nitro group.

Representative specific examples of the compound represented by the general formula [V] are shown below, but it should not be construed that the invention is limited thereto.

General formula [VI] Where A ₅ is Represents R ₂₃ and R ₂₄ each represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a hydroxyl group. R ₂₅ represents an alkyl group or an alkoxycarbonyl group. n represents 1, 2 or 3.

In the general formula [VI], examples of the halogen atom represented by R ₂₃ or R ₂₄ include a chlorine atom and a bromine atom, and examples of the alkyl group include a methyl group and an ethyl group. Examples include a methoxy group and an ethoxy group. Examples of the alkyl group represented by R ₂₅ include a methyl group and an ethyl group.
Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group.

Representative specific examples of the compound represented by the general formula [VI] are shown below, but it should not be construed that the invention is limited thereto.

General formula [VII] In the formula, X ₄ represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group.

A ₆ Represents Here, R ₂₆ represents a substituted or unsubstituted carbamoyl group, a carboxyl group or an ester group thereof. Z ₅ represents an atomic group necessary for forming a carbocyclic aromatic ring or a heterocyclic aromatic ring. R ₂₇ represents an alkyl group or an aryl group.

In the general formula [VII], examples of the halogen atom represented by X ₄ include a chlorine atom and a bromine atom, and examples of the alkyl group include a methyl group and an ethyl group. An ethoxy group is exemplified.

Examples of the substituted carbamoyl group represented by R ₂₆ include N-phenylcarbamoyl, N-ethylcarbamoyl, N-naphthylcarbamoyl, N-phenyl-N-
Examples include an ethylcarbamoyl group and an N, N-diphenylcarbamoyl group, and these groups may further have a substituent.

Examples of the ester group of the carboxyl group represented by R ₂₆ include And the like.

Carbocyclic aromatic ring or heterocyclic aromatic ring such as a benzene ring formed by Z _5, a naphthalene ring, a carbazole ring, a benzofuran ring, etc., may have a substituent on the ring.

Examples of the alkyl group represented by R ₂₇ include a methyl group and an ethyl group, and examples of the aryl group include a phenyl group. These groups may have a substituent.

Representative specific examples of the compound represented by the general formula [VII] are shown below, but it should not be construed that the invention is limited thereto.

The typical specific examples of the compounds represented by the general formulas [I] to [VII] are described above. As other specific examples, the general formula [I] is described, for example, in JP-A-58-70232 and JP-A-58-70232. 140
No. 745, general formula [II] is described in, for example, JP-A-53-13344.
No. 5, general formula [III] is described in, for example, JP-A-54-22834.
No. and general formula [IV] are described in, for example, JP-A-59-229564.
No. and the general formula [V] are described in, for example, JP-A-57-182747.
Nos. 58-115447 and 56-116040, and the general formula [VI] is described in, for example, JP-A-47-37543, and the general formula [VII] is described in, for example, JP-A-56-116039. Compounds can be mentioned.

Further, the bisazo compounds as described above can be easily synthesized by the methods described in the above publications.

The phthalocyanine-based compound used in the present invention can be any of a metal-free phthalocyanine compound and a metal phthalocyanine compound, for example, α, β, γ, τ, τ ′, η,
η ′, X-type metal-free phthalocyanine compounds and ε-type copper phthalocyanine compounds. Among them, the metal-free phthalocyanine compound has the feature of being excellent in sensitivity and charge stability. Some of the characteristic values of the metal-free phthalocyanine compound are as follows.

In addition, these metal-free phthalocyanine compounds are
49-4338, JP-A-60-19154, JP-A-58-1
It is described in detail in 82639. The ε-type copper phthalocyanine is described in Japanese Patent Publication No. 40-2780.

The polycyclic quinone-based compound used in the present invention includes an anthrone-based pigment represented by the following general formula [A], a dibenzpyrene quinone-based pigment represented by the following general formula [B], and a compound represented by the following general formula [C]. At least one selected from pyranthrone-based pigments can be used, but the general formula [A] is particularly preferable.

General formula [A] General formula [B] General formula [C] In the formula, X represents a halogen atom, a nitro group, a cyano group, an acyl group or a carboxyl group, n represents an integer of 0 to 4, and m represents an integer of 0 to 6.

Specific compounds of the anthantrone-based pigment represented by the general formula [A] are as follows.

Specific compound examples of the dibenzpyrenequinone pigment represented by the general formula [B] are as follows.

Specific examples of the pyranthrone-based pigment represented by the general formula [C] are as follows.

The polycyclic quinone-based compound as described above can be synthesized by a known method, but can also be obtained as a commercial product.

Although various configurations are known for the configuration of the electrophotographic photosensitive member, the electrophotographic photosensitive member of the present invention can take any of these forms.

Normally, the configuration is as shown in FIGS. 1 and 2, at least one of the above-mentioned bisazo compound and phthalocyanine compound is formed on the conductive support 1.
A photosensitive layer comprising a laminate of a charge generation layer 2 having a thickness of 0.5 μm to 5 μm containing a species and at least one kind of a polycyclic quinone-based compound, and a charge transport layer 3 containing a charge transport substance described later as a main component. 4 are provided, and in FIG. 1 and FIG.
The stacking order of the second load generation layer 2 and the charge transport layer 3 is different. Third
As shown in FIG. 4 and FIG. 4, the photosensitive layer 4 may be provided on a conductive support via an intermediate layer 5 such as an adhesive layer and a barrier layer. Thus, when the photosensitive layer 4 has a two-layer structure, a photosensitive member having the best electrophotographic characteristics can be obtained. In the present invention, a protective layer may be provided as the outermost layer.

The charge generation layer 2 constituting the two-layered photosensitive layer 4 is formed directly on the conductive support 1 or the charge transport layer 3 or, if necessary, on an intermediate layer 5 such as an adhesive layer or a barrier layer. For example, it can be formed by the following method.

M-1) A solution in which at least one selected from a bisazo-based compound and a phthalocyanine-based compound and at least one of a polycyclic quinone-based compound are dissolved together or separately in a suitable solvent, or a binder resin as required. A method of applying a mixed and dissolved solution.

M-2) At least one kind selected from a bisazo compound and a phthalocyanine compound and at least one kind of a polycyclic quinone compound are mixed together or separately in a dispersion medium by means of a ball mill, a homomixer, or the like in a dispersion medium.
μm or less, more preferably 1 μm or less), and applying a dispersion liquid mixed with an binder resin if necessary.

Solvents or dispersion media used for forming the charge generation layer include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone, methylethylkettle, cyclohexanone, benzene, Toluene, xylene, chloroform, 1,
2-dichloroethane, 1,2-dichloropropane, 1,1,2-
Trichloroethane, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethane, dichloromethane,
Examples thereof include tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, and methyl cellosolve.

The charge transport layer can be formed in the same manner as the charge generation layer.

As the binder resin used for forming the charge generation layer or the charge transport layer, any binder resin can be used, but it is preferable to use a hydrophobic, high dielectric constant, and electrically insulating film-forming polymer. preferable. Examples of such a high-molecular polymer include the following, but are not limited thereto.

P-1) Polycarbonate P-2) Polyester P-3) Methacrylic acid P-4) Acrylic resin P-5) Polyvinyl chloride P-6) Polyvinylidene chloride P-7) Polystyrene P-8) Polyvinyl acetate P -9) Styrene-butadiene copolymer P-10) Vinylidene chloride-acrylonitrile copolymer P-11) Vinyl chloride-vinyl acetate copolymer P-12) Vinyl chloride-vinyl acetate-maleic anhydride copolymer P- 13) Silicon resin P-14) Silicon-alkyd resin P-15) Phenol formaldehyde resin P-16) Styrene-alkyd resin P-17) Poly-N-vinylcarbazole P-18) Polyvinyl butyral P-19) Polyvinyl formal These binder resins can be used alone or as a mixture of two or more.

The thickness of the charge generation layer formed as described above is 0.5
The best electrophotographic characteristics can be obtained by setting the thickness to from 5 μm to 5 μm, preferably from 0.5 to 3 μm. In addition, since the film can be formed into a relatively thick film, coating defects during manufacturing hardly occur.

Further, in the charge generation layer formed as described above, the weight ratio of the binder to the charge generation material comprising at least one selected from bisazo compounds and phthalocyanine compounds and at least one polycyclic quinone compound is as follows. Preferably it is 100: 0 to 100: 500. If the content of the charge generating substance is less than this, photosensitivity is low and the residual potential is increased, and if it is more than this, dark decay and accepting potential are reduced.

Further, the combined ratio of at least one kind of the polycyclic quinone-based compound and at least one kind selected from the bisazo-based compound and the phthalocyanine-based compound is preferably from 100: 1 to 100: 30 by weight, and the bisazo-based compound and the phthalocyanine are preferably used. If the proportion of at least one selected from the series compounds is higher than this, the electrophotographic properties will be reduced.

Further, in the charge transport layer formed as described above, the charge transport material is a binder resin 100 in the charge transport layer.
20 to 200 parts by weight per part by weight is preferred, and particularly preferably 3 to 200 parts by weight.
0 to 150 parts by weight.

The thickness of the formed charge transport layer is preferably 5
To 50 μm, particularly preferably 5 to 30 μm.

The charge transporting material used in the present invention is not particularly limited, but includes, for example, oxazole derivatives, oxadianol derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, and bisimidazolidines. Derivatives, styryl compounds, hydrazone compounds, pyrazoline derivatives, amine derivatives, oxazolone derivatives,
Benzothiazole derivatives, benzimidazole derivatives,
Quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, and the like.

The charge transporting material used in the present invention has excellent transportability to the support side of holes generated during light irradiation, and is suitable for combination with the polycyclic quinone-based compound, bisazo-based compound, phthalocyanine-based compound, and the like. Preferably, the charge transport material is represented by the following general formulas (A), (B) and (C).

General formula (A) However, Ar ₁ , Ar ₂ , Ar ₄ each represents a substituted or unsubstituted aryl group, Ar ₃ represents a substituted or unsubstituted arylene group, R ₁ is a hydrogen atom, a substituted or unsubstituted alkyl group, or Represents a substituted or unsubstituted aryl group.

Specific examples of such compounds are described in detail in JP-A-58-65440, pp. 3-4, and JP-A-58-198043, pp. 3-6.

General formula (B) Here, R ₁ represents a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, and R ₂ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Are described in JP-A Nos. 58-134642 and 58-166354.

General formula (C) Here, R ₁ is a substituted or unsubstituted aryl group, R ₂ is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group,
A hydroxy group, R ₃ is a substituted or unsubstituted aryl group,
Represents a substituted or unsubstituted heterocyclic group. Methods for synthesizing these compounds and examples thereof are described in detail in JP-B-57-148750, which can be incorporated in the present invention.

Other preferred charge transporting substances of the present invention include hydrazone compounds described in JP-A-57-67940, JP-A-59-15252, and JP-A-57-101844, respectively.

As the dielectric support used in the electrophotographic photoreceptor of the present invention, a metal plate including an alloy, a metal drum or a conductive polymer, a conductive compound such as indium oxide or an alloy including an aluminum, palladium, gold, etc. Paper, plastic film, and the like, which are made conductive by applying, depositing, or laminating a thin metal layer, may be used. As the intermediate layer such as the adhesive layer or the barrier layer, an organic polymer substance such as polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose, aluminum oxide, or the like is used in addition to the polymer used as the binder resin.

Organic amines can be added to the photosensitive layer of the invention for the purpose of improving the charge generation function of the charge generation substance, and it is particularly preferable to add a secondary amine.

Such secondary amines include, for example, dimethylamine,
Diethylamine, di-n-propylamine, di-isopropylamine, di-nbutylamine, di-isobutylamine, di-n-amylamine, di-isoamylamine, di-n-hexylamine, di-isohexylamine, di-n
Pentylamine, di-isopentylamine, di-n-octylamine, di-isooctylamine, di-nnonylamine, di-isononylamine, di-ndecylamine, di-isodecylamine, di-nmonodecylamine, Examples thereof include di-isomonodecylamine, di-n-dodecylamine, and di-isododecylamine.

Further, the amount of the organic amine to be added is 1 time or less, preferably 0.2 to 0.005 times the mole of the charge generating substance.

Further, an antioxidant can be added to the photosensitive layer of the present invention for the purpose of preventing ozone deterioration.

Representative specific examples of such antioxidants are shown below, but are not limited thereto.

Group (I): hindered phenols dibutylhydroxytoluene, 2,2'-methylenebis (6-t-butyl-4-methylphenol), 4,4'-
Butylidenebis (6-t-butyl-3-methylphenol), 4,4'-thiobis (6-t-butyl-3-methylphenol), 2,2'-butylidenebis (6-t-butyl-4-methylphenol) ), Α-tocopherol, β
-Tocopherol, 2,2,4-trimethyl-6-hydroxy-7-tert-butylchroman, pentaerythyltetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2, 2'-thiodiethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,6-hexanediolbis [3- (3,5-di-t-butyl-4 -Hydroxyphenyl) propionate], butylhydroxyanisole,
Dibutylhydroxyanisole, 1- [2-｛(3,5-
Di-tert-butyl-4-hydroxyphenyl) propionyloxydiethyl] -4- [3- (3,5-di-tert-
Butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidyl.

Group (II): paraphenylenediamines N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p -Phenylenediamine, N, N'-diisopropyl-p-phenylenediamine, N, N'-dimethyl-N, N'-di-tert-butyl-p-phenylenediamine and the like.

Group (III): hydroquinones 2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone,
-Dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) -5-methylhydroquinone and the like.

Group (IV): organic sulfur compounds such as dilauryl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, and ditetradecyl 3,3'-thiodipropionate.

Group (V): Organophosphorus compounds Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine and the like.

These compounds are known as antioxidants for rubbers, plastics, oils and the like, and commercially available products can be easily obtained.

These antioxidants may be added to any of the charge generation layer, the charge transport layer, and the protective layer, but are preferably added to the charge transport layer. In this case, the amount of the antioxidant added is 0.1 to 100 parts by weight, preferably 1 to 50 parts by weight, particularly preferably 1 to 25 parts by weight based on 100 parts by weight of the charge transporting substance.

In the present invention, the charge generation layer may contain one or more kinds of electron accepting substances for the purpose of improving sensitivity, reducing residual potential, or reducing fatigue during repeated use.

Electron accepting substances that can be used here include
For example, succinic anhydride, maleic anhydride, dibromo maleic anhydride, phthalic anhydride, tetrachloro phthalic anhydride, tetrabromo phthalic anhydride, 3-nitro phthalic anhydride, 4-nitro phthalic anhydride, pyromellitic anhydride, merit anhydride Acid, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene, 1,3,5-trinitrobenzene, paranitrobenzonitrile, picryl chloride, quinone chlorimide,
Chloranil, bulmanil, dichlorodianoparabenzoquinone, anthraquinone, dinitroanthraquinone, 2,7
-Dinitrofluorenone, 2,4,7-tronitrofluorenone, 2,4,5,7-tetranitrofluorenone, 9-fluorenylidene [sidianomethylenemalonodinitrile],
Polynitro-9-fluorenylidene- [dicyanomethylenemalonodinitrile], picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, 3,5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid, 3,5 −
Examples thereof include dinitrosalicylic acid, phthalic acid, melitic acid, and other compounds having a high electron affinity.

The amount of the electron-accepting substance to be added depends on the weight ratio of the charge generating substance:
Electron accepting substance = 100: 0.01 to 200, preferably 100: 0.1 to
It is 100.

The electron accepting substance may be added to the charge transport layer. The amount of the electron-accepting substance to be added to such a layer is 100: 0.01 to 100, preferably 100:
0.1 to 50.

In addition, the photoreceptor of the present invention may further contain, if necessary, an ultraviolet absorber or the like for the purpose of protecting the photosensitive layer, or may contain a dye for correcting color sensitivity.

The electrophotographic photoreceptor of the present invention is configured as described above, and has high sensitivity, as is clear from the examples described later,
In particular, it has sufficient sensitivity even when used in high-speed copying machines and small-sized copying machines. The electrophotographic photoreceptor of the present invention has stable characteristics even when repeatedly used.

Further, the electrophotographic photoreceptor of the present invention has good properties as a photoreceptor by forming a relatively thick charge generating layer, and thus has few coating defects during production as described above and is excellent in productivity. It is a thing.

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples.
This does not limit the embodiments of the present invention.

Example 1 After dissolving 5 g of a polycarbonate resin (Panlite L-1250, manufactured by Teijin Chemicals Ltd.) in 200 ml of 1,2-dichloroethane, 10 g of an exemplary polycyclic quinone compound [A3] was mixed as a charge generating substance CGM2. Then, the mixture was dispersed with a sand grinder for 10 hours. This is designated as solution A.

Next, after dissolving 1 g of the above polycarbonate resin in 120 ml of 1,2-dichloroethane, 2 g of the exemplified bisazo compound No. I-22 as the charge generating substance CGM1 was mixed and dispersed with a sand grinder for 10 hours. This is designated as solution B.

The above solution A and solution B are used alone or mixed with stirring to form a coating solution for forming a charge generating layer. Using this coating solution, the solution is coated on an aluminum drum by a dip coating method.
A charge generation layer was formed. At this time, the film thickness was variously changed by changing the pulling speed from the coating solution.

Next, a charge transport layer having a thickness of about 20 μm after drying was laminated on the above-mentioned charge generation layer by the same dip coating method using a coating liquid for forming a charge transport layer having the following composition to obtain a photoreceptor.

A characteristic evaluation test of the thus obtained photoreceptor sample was performed as follows.

[Sensitivity test] Using an electrostatic charging tester EPA-8100 (manufactured by Kawaguchi Electric Co., Ltd.), the exposure amount E1 / 2 (lux) required for the photoconductor surface potential to be reduced by half from the initial charging potential Va (V). .sec).

[Repeatability test] Using the electrostatic charging tester EPA-8100, measure the change ΔVa ^{0 → 100} (V) in the first and 100th charge potentials when charging → exposure → discharge 100 times. did.

 Table 1 summarizes the obtained results.

From the results in Table 1, it is clear that the photoreceptor of the present invention shows superior performance in all respects of sensitivity, repetition characteristics, and productivity as compared with the comparative photoreceptor.

Example-2 The combination of the charge generating substances used was changed as shown in Table 2, and the polycarbonate resin used for the coating solution for forming the charge transport layer was changed to Iupilon Z-200 (manufactured by Mitsubishi Gas Chemical Co., Ltd.). A sample was prepared in the same manner as in Example 1 except for replacing, and a property evaluation test similar to that in Example 1 was performed.
Table 2 shows the obtained results.

From the results in Table 2, it can be seen that the photoreceptor of the present invention exhibits excellent performance in all respects of sensitivity, repetition characteristics and productivity.

Example 3 The charge generation materials used were changed as shown in Table 3, and the polycarbonate resin used for the coating solution for forming the charge transport layer was changed to Iupilon Z-200 (described above). To A sample was prepared in the same manner as in Example 1 except that
The same property evaluation test as in Example 1 was performed, and the obtained results are shown in Table-3.

From the results in Table 3, it can be seen that the photoreceptor of the present invention shows excellent performance in all respects of sensitivity, repetition characteristics and productivity.

Example-4 The charge-transporting substance used was changed as shown in Table 4, and the polycarbonate resin used for the coating liquid for forming the charge-transporting layer was replaced with Iupilon Z-200 (described above). To A sample was prepared in the same manner as in Example 1 except that
The same property evaluation test as in Example 1 was performed, and the obtained results are shown in Table-4.

The results in Table 4 show that the photoreceptor of the present invention shows excellent performance in all respects of sensitivity, repetition characteristics and productivity.

[Brief description of the drawings]

FIGS. 1 to 4 are cross-sectional views each showing an example of the configuration of the photoconductor of the present invention. DESCRIPTION OF SYMBOLS 1 ... Conductive support 2 ... Charge generation layer 3 ... Charge transport layer 4 ... Photosensitive layer 5 ... Intermediate layer

──────────────────────────────────────────────────の Continuation of front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location G03G 5/06 351 G03G 5/06 351A 352 352 367 367 370 370 376 376

Claims (1)

(57) [Claims] 1. An electrophotographic photoreceptor having at least a charge generation layer and a charge transport layer on a conductive support, wherein the charge generation layer has the following general formulas [I], [II] and [II] in the same layer.
At least one selected from bisazo compounds, metal-free phthalocyanine compounds and metal phthalocyanine compounds represented by I], [IV], [V], [VI] or [VII]
An electrophotographic photoreceptor containing at least one of a species and a polycyclic quinone-based compound, and wherein the same layer of the charge generation layer has a thickness of 0.5 μm to 5 μm. General formula [I] In the formula, Ar ₁ , Ar ₂ and Ar ₃ each represent a substituted or unsubstituted aromatic carbocyclic residue or a substituted or unsubstituted aromatic heterocyclic residue. R ₁ , R ₂ , R ₃ and R ₄ each represent a hydrogen atom or an electron-withdrawing group. However, at least one of R _{1 to} R ₄ is an electro withdrawing group. A ₁ is Represents Where X ₁ is a hydroxy group, Or -NHSO ₂ -R ₈ (where R ₆ and R ₇ each represent a hydrogen atom or a substituted or unsubstituted alkyl group, and R ₈ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. Represents.). Y ₁ is a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted carbamoyl group,
Represents a substituted or unsubstituted sulfamoyl group, a carboxyl group or a sulfo group. Z ₁ represents an atomic group necessary for forming a substituted or unsubstituted carbocyclic aromatic ring or a substituted or unsubstituted heterocyclic aromatic ring. R ₅ represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted carbamoyl group, a carboxyl group or an ester group thereof. A ′ represents a substituted or unsubstituted aryl group. n represents an integer of 1, 2, or 3, and m represents an integer of 0, 1, or 2. General formula [II] Where A ₂ is Represents Here, Ar ₄ represents an aromatic group or a heterocyclic group. Ar ₅ and Ar
₆ represents an aromatic ring group. R ₉ and R ₁₁ each represent a hydrogen atom, an alkyl group or an aryl group. R ₁₀ represents an alkyl group, a carboxyl group or an ester group thereof. Z ₂
Represents an atom group necessary for forming an aromatic ring or a heterocyclic ring. General formula [III] Wherein, A ₂ has the same meaning as A ₂ in the general formula [II]. General formula [IV] In the formula, R ₁₂ and R ₁₃ each represent a hydrogen atom, a halogen atom or an alkyl group. X ₂ is -O- or (R ₁₄ represents a hydrogen atom, an alkyl group or an aryl group.) A ₃ Represents Z ₃ represents an arylene group. R ₁₅ represents an alkyl group or an aryl group. R ₁₆ represents a hydrogen atom, an alkyl group or an aryl group. Ar ₇ represents an aryl group. Y ₂ represents an atom group necessary for forming an aromatic carbocyclic ring or a heterocyclic ring. General formula [V] In the formula, Ar ₈ and Ar ₉ each represent a substituted or unsubstituted aromatic carbocyclic residue or a substituted or unsubstituted aromatic hetero residue. R ₁₇ and R ₁₆ each represent a hydrogen atom or an electron-withdrawing group. However, at least one of R ₁₇ and R ₁₈ is an electron-withdrawing group. A ₄ Represents Here, X ₃ is a hydroxy group, Or —NHSO ₂ —R ₂₂ (where R ₂₀ and R ₂₁ each represent a hydrogen atom or a substituted or unsubstituted alkyl group, and R ₂₂ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl. ). Y ₃ is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted sulfamoyl group, a carboxy group or an ester group thereof, or a sulfo group Represents Z ₄ represents a group of atoms necessary for forming a substituted or unsubstituted carbocyclic aromatic ring or a substituted or unsubstituted heterocyclic aromatic ring. R ₁₉ represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted carbamoyl group, a carboxyl group or an ester group thereof, and A ″ represents a substituted or unsubstituted aryl group N represents an integer of 1, 2 or 3. m represents an integer of 0, 1 or 2. General formula [VI] Where A ₅ is Represents R ₂₃ and R ₂₄ each represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a hydroxyl group. R ₂₅ represents an alkyl group or an alkoxycarbonyl group. n represents 1, 2 or 3. General formula [VII] In the formula, X ₄ represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. A ₆ Represents Here, R ₂₆ represents a substituted or unsubstituted carbamoyl group, a carboxyl group or an ester group thereof.
Z ₅ represents an atomic group necessary to form a carbocyclic aromatic ring or heterocyclic aromatic ring. R ₂₇ represents an alkyl group or an aryl group.