JP2002091044A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having excellent electric characteristics and environmental characteristics. SOLUTION: In the electrophotographic photoreceptor having a base coating layer and photosensitive layer formed in this order on a conductive supporting body, the base coating layer contains an electron transfer organic compound and polyamide resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member. Specifically, the present invention relates to an electrophotographic photosensitive member having an undercoat layer between a conductive support and a photosensitive layer.

[0002]

2. Description of the Related Art An electrophotographic photoreceptor is obtained by forming a photosensitive layer on a conductive surface of a support. Generally, the electrophotographic photoreceptor has improved adhesion between the photosensitive layer and the support, improved coating properties of the photosensitive layer, and the like. Surface protection,
A layer called a blocking layer (intermediate layer) is interposed for covering defects on the support, protecting the photosensitive layer from electrical breakdown, improving the carrier injectability of the photosensitive layer, and the like. The blocking layer is typically an alumite layer obtained by anodizing aluminum, or a polyurethane, a polyamide, a polyvinyl alcohol, an epoxyethylene-acrylic acid copolymer, an ethylene-vinyl acetate copolymer, casein, methylcellulose, It is composed of a layer mainly composed of a resin such as nitrocellulose and phenol resin, and these may be used in combination.

[0003] However, depending on the composition of the charge generation layer, the movement of the charge carriers to flow into the support side is hindered.
In the charge generation layer, recombination with charge carriers of other polarity or accumulation at the boundary between the undercoat layer and the charge generation layer to form a barrier due to space charge, so the charge potential decreases due to repeated use, and the residual potential decreases. There were cases in which there was a phenomenon such as a rise. Further, these undercoat layers have a drawback that the characteristics of the photoreceptor are greatly changed by humidity because the transport of charges is mainly carried by moisture in the undercoat layer.

As means for preventing these defects, it has been proposed to include a charge transport material in an undercoat layer. For example, Japanese Patent Publication No. 61-35555 discloses that a barrier layer containing a non-hydrophilic peptide polymer and an electron donating substance or an electron accepting substance is provided. JP-A-61-80158 discloses that an undercoat layer containing an electron-donating substance is provided, and JP-A-61-204640 discloses that an undercoat layer containing a hydrazone compound is provided. It is described that an undercoat layer including a charge transporting material such as pyrazoline, thiazole, oxadiazole, oxazole, hydrazone, ketazine, azine, carbazole, and polyvinylcarbazole is provided.

On the other hand, to solve the above-mentioned problems by making the intermediate layer contain an electron-accepting substance so as to allow electrons to easily pass therethrough is disclosed in Japanese Patent Publication No. 61-35551 and Japanese Patent Publication No. 61-55551. It is described in, for example, JP-A-59-160147. Furthermore, JP-A-58-209751 discloses that a precoat layer containing an N-type dye or a pigment is provided, and JP-A-63-210848 discloses an undercoating layer containing an electron-migrating pigment. It is described that a pull layer is provided.

However, when the electron-donating substance is contained in the undercoat layer as described above, electrons generated in the photosensitive layer tend to become traps, and the electrons recombine with holes to cause a decrease in sensitivity. Therefore, there is a problem that a sufficient function as an undercoat layer cannot be achieved. On the other hand, when an electron-accepting substance is contained in the undercoat layer, the undercoat layer functions sufficiently as an undercoat layer.
551 and JP-A-59-160147 are soluble in a solvent. Therefore, when a photosensitive layer is formed on an undercoat layer by coating,
In particular, when dip coating is performed, there is a disadvantage that the electron-accepting substance is eluted into the photosensitive layer or the coating solution. Also, Japanese Patent Application Laid-Open
209,751 and JP-A-63-210848
In the case of incorporating a pigment as disclosed in JP-A No. 10-133, the pigment itself is hardly soluble or insoluble in a solvent and therefore does not elute into the photosensitive layer, but is dispersed by a resin and applied by a method. Since the undercoat layer is formed, the resin is soluble in the solvent, and the application of the upper photosensitive layer dissolves the resin, thereby causing a coating film defect, thereby failing to function sufficiently as the undercoat layer. There was a disadvantage.

Further, Japanese Patent Application Laid-Open No. 8-146439 discloses an electrophotographic photoreceptor containing an electron transporting pigment such as a perylene pigment in an undercoat layer.
JP-A-228125 discloses an electrophotographic photoreceptor containing a polyamide resin binder and polyol-coated titanium oxide particles in an undercoat layer. However,
Even with these, the environmental dependence of the electrical characteristics and image characteristics has not always been sufficiently satisfied.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor having excellent electrical characteristics with little environmental change.

[0009]

As a result of various studies on the material of the undercoat layer, the present inventors have found that a combination of a polyamide resin having a specific diamine structural unit in a molecule and a charge transporting organic compound is particularly effective. The present inventors have found that the present invention exerts excellent effects in terms of environmental characteristics and completed the present invention.

That is, the gist of the present invention is that a conductive support is
An electrophotographic photoconductor provided with an undercoat layer and a photosensitive layer in this order, wherein the undercoat layer contains an electron-transporting organic compound and a polyamide resin,
Exists.

The electrophotographic photoreceptor of the present invention has an undercoat layer and a photosensitive layer provided on a conductive support in this order. The electrophotographic photoreceptor of the present invention, in addition to these layers,
For example, an overcoat layer or the like can be provided as needed.

Examples of the conductive support include metals such as aluminum, nickel, chromium, and stainless steel, and aluminum, titanium, nickel, chromium, stainless steel, gold, vanadium, tin oxide, indium oxide, and ITO.
And plastic films coated with or impregnated with a conductivity-imparting agent, and plastic films. These conductive supports are used in an appropriate shape such as a drum shape, a sheet shape, and a plate shape, but are not limited thereto.

When the electrophotographic photosensitive member is in the form of a drum, aluminum is preferred. The undercoat layer used in the present invention contains a polyamide resin as a binder resin. As the diamine structural unit constituting the polyamide resin used in the present invention, a known diamine can be used, but an alkane diamine such as hexamethylene diamine or octamethylene diamine or a cycloamine such as cyclohexane-1,4-diamine is preferable. Alkanediamine is used. The polyamide resin used in the present invention preferably contains an aliphatic diamine having 10 to 20 carbon atoms as a diamine structural unit. Among them, it is more preferable to contain a diamine structural unit represented by the following general formula (I) as a copolymerization component.

[0014]

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(In the general formula (I), R ^{1 to} R ¹⁶ each independently represent a hydrogen atom, a halogen atom, an alkyl group optionally substituted with a halogen atom, an alkoxy group optionally substituted with a halogen atom. R ¹⁷ and R ¹⁸ each independently represent a hydrogen atom, an alkyl group optionally substituted with a halogen atom, or an alkylthio group optionally substituted with a halogen atom; In formula (I), R ^{1 to} R ¹⁶ each independently represent a hydrogen atom; a halogen atom such as a fluorine atom or a chlorine atom; a methyl group, an ethyl group, a propyl group, or an isopropyl group. Group, butyl group, isobutyl group, pentyl group, hexyl group, cyclopentyl group, cyclohexyl group, chloromethyl group, chloroethyl group, trifluoromethyl group, halogen atom An alkyl group which may be substituted; a halogen atom such as an alkoxy group, a methylthio group, an ethylthio group, and a chloromethylthio group which may be substituted with a halogen atom such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a chloromethoxy group; Represents an alkylthio group which may be substituted with an atom, of which a hydrogen atom, a fluorine atom, a chlorine atom,
A methyl group, an ethyl group and a methoxy group are preferred, and a hydrogen atom and a methyl group are more preferred.

R ¹⁷ and R ¹⁸ are each independently a hydrogen atom;
Substituted with halogen atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, cyclopentyl, cyclohexyl, chloromethyl, chloroethyl, trifluoromethyl, etc. And an alkoxy group which may be substituted with a halogen atom such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a chloromethoxy group. Of these, a hydrogen atom, a methyl group and an ethyl group are exemplified. Preferred are a hydrogen atom and a methyl group.

The dicarboxylic acid structural unit copolymerized with the diamine structural unit is not particularly limited, and a known dicarboxylic acid can be used. Preferably, butanedicarboxylic acid, pentanedicarboxylic acid, hexanedicarboxylic acid, An alkanedicarboxylic acid (polymethylenedicarboxylic acid) such as dodecanedicarboxylic acid, octadecanedicarboxylic acid, or eicosanedicarboxylic acid, or a cycloalkanedicarboxylic acid such as cyclopentanedicarboxylic acid or cyclohexanedicarboxylic acid is used.

Further, together with these diamine structural units and dicarboxylic acid structural units, ω-amino acid structural units can be used in combination as copolymerized units. The ω-amino acid that can be used in combination is not particularly limited, and ω is preferably used.
Examples of -amino acids include 5-aminopentanoic acid, 6-aminohexanoic acid, 7-aminoheptanoic acid, and 8-aminooctanoic acid, and these intramolecular lactams can also be preferably used as ω-amino acid structural units.

In the polyamide resin used in the present invention, the aliphatic diamine structural unit having 10 to 20 carbon atoms is preferably 3% by number or more, more preferably 5% by number or more, and more preferably 10% by number or more of all the structural units. Particularly preferred. Also,
The number is preferably 50% or less, more preferably 40% or less, particularly preferably 30% or less. Carbon number 10-2
If the content of the aliphatic diamine structural unit of 0 is significantly out of the above range, problems may occur in coatability and storage stability.

The number average molecular weight of the copolymerized polyamide used in the present invention is from 10,000 to 50,000, more preferably from 15,000 to 35,000. If the ratio is out of this range, there may be a problem in applicability and storage stability.
In the above structure, more preferably, the amide group is at the para position, and the other groups are a hydrogen atom, a methyl group and an ethyl group.

The electron-transporting organic compound used in the present invention can be used without any particular limitation as long as it is an organic compound having an electron-transporting ability. Specifically, polycyclic quinone pigments, perylene pigments, azo pigments And indigo pigments and quinacridone pigments. Of these, perylene pigments are preferred. Particularly preferred perylene pigments are those composed of any one of the compounds represented by the following general formulas (II), (III) and (IV).

[0022]

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(In the general formula (II), R ¹⁹ and R ²⁰ each independently represent a hydrogen atom, an aryl group which may have a substituent, an alkyl group which may have a substituent, (In the general formula (III), Ar ¹ and Ar ² each independently represent an aromatic hydrocarbon ring which may have a substituent.) (In the general formula (IV), Ar ³ and Ar ⁴ each independently represent an aromatic hydrocarbon ring which may have a substituent.) In the general formula (II), R ¹⁹ and R ²⁰ are Each independently represents a hydrogen atom, an aryl group which may have a substituent, an alkyl group which may have a substituent, or an aralkyl group which may have a substituent; Are preferably a phenyl group and a naphthyl group, and the substituent on the aryl group is a methyl group, an ethyl group Alkyl groups having 4 or less carbon atoms such as isopropyl group and tertiary butyl group, halogen atoms such as fluorine atom, chlorine atom and bromine atom, alkoxy having 4 or less carbon atoms such as methoxy group, ethoxy group and propoxy group, and butoxy group. Groups are preferred.

The alkyl group represented by R ¹⁹ and R ²⁰ preferably has 10 or less carbon atoms, more preferably 4 or less carbon atoms. As the substituent on the alkyl group, a halogen atom such as a fluorine atom, a chlorine atom, and a bromine atom, an alkoxy group having 4 or less carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, and a butoxy group are preferable. The aralkyl group in R ¹⁹ and R ²⁰ is preferably a benzyl group or a phenethyl group, and the substituent on the aralkyl group may be a methyl group, an ethyl group, an isopropyl group,
An alkyl group having 4 or less carbon atoms such as a tertiary butyl group,
A halogen atom such as a fluorine atom, a chlorine atom and a bromine atom, an alkoxy group having 4 or less carbon atoms such as a methoxy group, an ethoxy group and a propoxy group, and a butoxy group are preferred.

In the present invention, the pulling layer is formed by mixing / dispersing an electron transporting organic compound in a polyamide resin.
The proportion of the electron transporting organic compound in the undercoat layer is preferably from 10 to 500 parts by weight based on 100 parts by weight of the binder polymer, from the viewpoint of storage stability of the dispersion and applicability.
150 to 500 parts by weight is more preferred.

As a mixing / dispersing method, an ordinary method using a ball mill, a roll mill, a sand mill, an attritor, an ultrasonic wave or the like is applied. The mixing / dispersion is carried out in an organic solvent. As the organic solvent, any one that does not cause gelation or aggregation when the binder resin is dissolved and the electron transporting pigment is mixed / dispersed, Anything can be used. For example, methanol, ethanol, n-propanol, n
-Butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate,
Commonly used organic solvents such as dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene can be used alone or in combination of two or more.

The undercoat layer preferably contains fine particles of metal oxide such as alumina or titania, or an organic or inorganic dye capable of absorbing laser light, particularly for the purpose of preventing interference fringes during laser exposure. It is effective. The thickness of the undercoat layer is generally set in the range of 0.1 to 20 μm, preferably 0.5 to 10 μm. The undercoat layer can be formed by a commonly used coating method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method. . After application, drying is performed to obtain an undercoat layer.
It is performed at a temperature at which a film can be formed.

The photosensitive layer used in the present invention may have a single-layer structure, but preferably has a laminated structure in which a charge generation layer and a charge transfer layer are separated. When the photosensitive layer has a single-layer structure, a known material in which a photosensitive material is dispersed in a binder material is used. For example, a dye-sensitized ZnO photosensitive layer, Cd
An S photosensitive layer and a photosensitive layer in which a charge generation material is dispersed in a charge transfer material are exemplified. When the photosensitive layer has a laminated structure, each layer is provided on a conductive support or an undercoat layer in the order of a charge generation layer and a charge transfer layer.

As the charge generating material used for the charge generating layer, any known materials can be used. Selenium and its alloys, arsenic-selenium, cadmium sulfide, zinc oxide, other inorganic photoconductive materials, phthalocyanine, Azo dye, quinacridone, polycyclic quinone, pyrylium salt, indigo, thioindigo, anthantrone, pyranthrone,
Pigments and dyes composed of various organic compounds such as cyanine can be used. Among them, metals such as metal-free phthalocyanine, copper, indium chloride, gallium chloride, tin, oxytitanium, zinc, and vanadium, or oxides, phthalocyanines coordinated with chloride, azo pigments such as monoazo, bisazo, trisazo, and polyazos Is preferred.

Of these, oxytitanium phthalocyanine is more preferred from the viewpoint of sensitivity when used in an image forming apparatus equipped with an exposure device using a laser beam in the range of 530 to 850 nm. Most preferred is Y-type oxytitanium phthalocyanine having a characteristic peak at an angle (2θ ± 0.2 °) = 27.3 °.

The charge generation layer can be obtained by applying and drying a coating solution obtained by dissolving or dispersing fine particles of these substances and a binder polymer in a solvent. Examples of the binder include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic acid ester, methacrylic acid ester, vinyl alcohol, and ethyl vinyl ether, polyvinyl acetal, polycarbonate, polyester, polyamide, polyurethane, and cellulose ether. Phenoxy resin, silicon resin, epoxy resin and the like.

The ratio of the charge generating substance to the binder polymer is not particularly limited, but is generally 5 to 500 parts by weight, preferably 20 to 30 parts by weight, per 100 parts by weight of the charge generating substance.
0 parts by weight of binder polymer are used. Further, the charge generation layer may be a deposited film of the above-described charge generation substance. The thickness of the charge generation layer is 0.05 to 5 μm, preferably 0.1 to 5 μm.
２2 μm.

The charge transfer layer is mixed with a known polymer having excellent performance as a binder on the charge generation layer, dissolved in a suitable solvent together with the charge transfer material, and if necessary, an electron-accepting compound. Alternatively, it can be produced by applying a coating liquid obtained by adding a plasticizer, a pigment or other additives. The thickness of the charge transfer layer is usually in the range of 10 to 50 μm, preferably 13 to 35 μm.

Examples of the charge transfer material in the charge transfer layer include high molecular compounds such as polyvinyl carbazole, polyvinyl pyrene and polyacenaphthylene, and low charge compounds such as various pyrazoline derivatives, oxazole derivatives, hydrazone derivatives, stilbene derivatives and arylamine derivatives. Molecular compounds can be used. Among these, compounds represented by the following general formula (V) are preferable in terms of sensitivity and other electrical characteristics. In particular, the compound represented by the general formula (V) is preferable since oxytitanium phthalocyanine is used as the charge generating substance, since the electrical characteristics are significantly improved.

[0035]

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(In the general formula (V), Ar ⁵ represents an optionally substituted benzene ring, an optionally substituted naphthalene ring, or an optionally substituted biphenyl ring;
Ar ^{6 to} Ar ⁹ each independently represent an optionally substituted aromatic ring. In the general formula (1), Ar ⁵ represents a benzene ring which may be substituted, a naphthalene ring which may be substituted, or a biphenyl ring which may be substituted. A biphenyl ring is also preferable. As the substituent, a halogen atom, an alkyl group having 4 or less carbon atoms, an alkoxy group having 3 or less carbon atoms, an alkylthio group having 3 or less carbon atoms, a cyano group, and a nitro group are preferable. Among them, a methyl group, a fluorine atom, and a chlorine atom are preferable. Atoms are more preferred.
However, an unsubstituted aromatic ring is most preferred.

Ar ^{6 to} Ar ⁹ each independently represent an optionally substituted aromatic ring, and the aromatic ring may be any of an aromatic hydrocarbon and an aromatic heterocyclic ring. Is a benzene ring, a naphthalene ring, a phenanthrene ring,
Anthracene ring, pyridine ring, pyrrole ring, furan ring,
A thiophene ring, a benzofuran ring, a benzothiophene ring and the like. Of these, a benzene ring, a naphthalene ring and a thiophene ring are preferred.

The substituent on the aromatic ring includes a halogen atom, an alkyl group having 4 or less carbon atoms, an alkoxy group having 3 or less carbon atoms, an alkylthio group having 3 or less carbon atoms, a cyano group, a nitro group, A substituent represented by the following general formula (VI) is preferable.

[0039]

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(In the general formula (VI), Ar ¹⁰ represents a halogen atom or a phenyl group which may be substituted with an alkyl group. R ²¹ and R ²² each independently represent a hydrogen atom or a methyl group. n represents 1, 2 or 3.) In the general formula (VI), Ar ¹⁰ represents a phenyl group which may be substituted with a halogen atom or an alkyl group, but is preferably an unsubstituted phenyl group. R ²¹ and R ²² represent a hydrogen atom or a methyl group, and a hydrogen atom is preferable. n
Represents 1, 2, or 3, but is preferably 2.

Further, among the charge transfer agent compounds represented by the general formula (V), compounds represented by the following general formula (VII) are particularly effective.

[0042]

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In the general formula (VII), R ²¹ , R ²² , A
r ¹⁰ and n have the same meanings as described above. Also, R ²³ , to R
²⁶ is each independently a hydrogen atom or a methyl group. As the binder used for the charge transfer layer, a polymer that has good compatibility with the charge transfer material and does not crystallize or phase-separate the charge transfer material after forming the coating film is preferable.
Examples thereof include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic acid ester, methacrylic acid ester, vinyl alcohol, and ethyl vinyl ether, polyvinyl acetal, polycarbonate, polyester, polysulfone, and polyphenylene oxide. , Polyurethane, cellulose ester,
Examples include cellulose ether, phenoxy resin, silicon resin, epoxy resin and the like.

The binder used in the charge transfer layer preferably has a high strength and is at least partially compatible with the above-mentioned polysiloxane compound. In view of this, polycarbonate, polyarylate or a mixture thereof is preferably used. Can be Examples of the electron-accepting compound optionally contained in the charge transfer layer include cyano compounds such as tetracyanoquinodimethane, dicyanoquinomethane, aromatic esters having a dicyanoquinovinyl group, and 2,4,6-
Nitro compounds such as trinitrofluorenone, condensed polycyclic aromatic compounds such as perylene, diphenoquinone derivatives, quinones, aldehydes, ketones, esters, acid anhydrides, phthalides, substituted and unsubstituted metal complexes of salicylic acid, substitution And metal salts of unsubstituted salicylic acid, metal complexes of aromatic carboxylic acids, and metal salts of aromatic carboxylic acids.

Preferably, cyano compounds, nitro compounds, condensed polycyclic aromatic compounds, diphenoquinone derivatives, metal complexes of substituted and unsubstituted salicylic acids, metal salts of substituted and unsubstituted salicylic acids, metal complexes of aromatic carboxylic acids, aromatic complexes It is preferred to use metal salts of carboxylic acids. Further, the photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a well-known plasticizer, antioxidant, and ultraviolet absorber in order to improve film formability, flexibility, applicability, and mechanical strength. good.

When an overcoat layer is further provided on the charge transfer layer, examples of the binder resin include polyvinyl methyl ether, poly-N-vinyl imidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, polyamide, Casein, gelatin, polyethylene, polyester, phenolic resin, vinyl chloride-vinyl acetate copolymer, epoxy resin, polyvinylpyrrolidone, polyvinylpyridine, polyurethane, polyglutamic acid, polyacrylic acid, polyamide resin, silicone resin, and fluorine resin are used. Preferably, polyurethane, silicone resin and fluorine resin are used. The thickness of the overcoat layer is usually 0.01 to 100 μm, preferably 1 to 10 μm.

[0047]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the present invention. The "part" used in the examples
Indicates "parts by weight" unless otherwise specified. [Preparation of dispersion (P1)] Perylene pigment (PV FAST B RE
D; Clariant Japan) and a mixed alcohol (methanol / 1-propanol = 70/30) were dispersed with a paint shaker for 3 hours.

[0048] The obtained perylene pigment dispersion was prepared by the method described in
No. 31870, a mixed alcohol (methanol / 1-propanol = 70/3) of a random copolymerized polyamide having the following structure produced by the production method described in Examples
0) Added to solution. Finally, a dispersion having a solid content concentration of 5% by weight with a perylene pigment / nylon ratio of 2/1 (weight ratio) was prepared and used as a dispersion (P1).

[0049]

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[Preparation of Dispersion (P2)] Perylene pigment (PV
FAST B RED; manufactured by Clariant Japan) and a mixed alcohol (methanol / 1-propanol = 70/30) were dispersed with a paint shaker for 3 hours.

The obtained perylene pigment dispersion was treated with polyvinyl butyral (trade name # 6000, manufactured by Denki Kagaku Kogyo KK).
-C) and a mixed alcohol (methanol / 1-propanol = 70/30) solution. Finally, a dispersion having a solid content concentration of 5% by weight was prepared at a perylene pigment / polyvinyl butyral ratio of 2/1 (weight ratio), and this was used as a dispersion (P2). [Preparation of Dispersion (P3)] Titanium oxide manufactured by Ishihara Sangyo Co., Ltd., product name TTO-55N (crystal rutile primary particle size: 0.03-0.05 μm) and mixed alcohol (methanol / 1-propanol = 70) / 30) was dispersed in a ball mill for 16 hours. The titanium oxide dispersion obtained here was added to a mixed alcohol (methanol / 1-propanol = 70/30) solution of the above random copolymerized polyamide. Finally, a dispersion having a solid content concentration of 16% was prepared at a titanium oxide / nylon ratio of 3/1 (weight ratio), and this was designated as a dispersion (P3). [Preparation of Dispersion (P4)] TTO55 as titanium oxide
A liquid dispersion (P4) was prepared in exactly the same manner as the dispersion liquid (P3) except that N was treated with dimethyldimethoxysilane at 3% by weight. Example 1 An aluminum cylinder having an outer diameter of 30 mm, a length of 254 mm and a wall thickness of 1.0 mm having a mirror-finished surface was dip-coated on the dispersion liquid (P1), and the dried film thickness was 1.25.
After providing an undercoat layer so as to have a thickness of μm, 1,2-dimethoxyethane 500 was added to 10 parts of β-type oxytitanium phthalocyanine and 5 parts of polyvinyl butyral (trade name # 6000-C, manufactured by Denki Kagaku Kogyo KK). The mixture was added and pulverized and dispersed by a sand grind mill. An aluminum cylinder provided with an undercoat layer was dip-coated on this dispersion, and its dry film thickness was 0.3 g / m 2 (about 0.3 μm).
m) was provided with a charge generation layer.

Next, this aluminum cylinder was
56 parts by weight of the hydrazone compound (A), 14 parts by weight of the hydrazone compound (B), 2 parts by weight of the cyan compound (C), and the production method described in Examples of JP-A-3-221962. Drying is carried out by dip coating a solution prepared by dissolving 100 parts of the produced polycarbonate resin having the following two repeating structural units (D) (monomer molar ratio: 1: 1) in a mixed solvent of 1,4-dioxane / tetrahydrofuran. The charge transfer layer was provided so as to have a thickness of 17 μm. The drum thus obtained is referred to as a photoconductor A1.

[0053]

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[0054]

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Comparative Example 2 The aluminum cylinder used in Example 1 was dip-coated with the dispersion (P2), and an undercoat layer was provided so that the dry film thickness was 1.25 μm. A photoconductor was obtained in the same manner as in Example 1. The drum thus obtained is designated as B1. [Comparative Example 3] The aluminum cylinder used in Example 1 was dip-coated with the dispersion liquid (P3), and the dried film thickness was 1.
A photoconductor was obtained by the same way as that of Example 1 except that an undercoat layer was provided so as to have a thickness of 25 μm. The drum thus obtained is designated as B2. [Comparative Example 4] The aluminum cylinder used in Example 1 was dip-coated with the dispersion liquid (P4), and the dried film thickness was 1.
A photoconductor was obtained by the same way as that of Example 1 except that an undercoat layer was provided so as to have a thickness of 25 μm. The drum thus obtained is designated as B3. [Comparative Example 5] Photoconductor B4 was obtained in the same manner as in Example 1, except that no undercoat layer was provided. [Evaluation of image] Next, these photoconductors were converted to a commercially available laser printer (LASER manufactured by HEWLETT PACKARD).
JET 4 Plus), temperature / humidity is 5 ℃
Printing was performed in each environment of / 10%, 25 ° C./50%, and 35 ° C./85%, and image evaluation was performed. Table 1 shows the fog value under each environment.

The fog value of the standard sample was 94.
The whiteness of the paper (A4 size) before printing was measured using this whiteness meter, and the white paper signal of the same paper was sent to the laser printer described above. Printing was performed by inputting, and then the whiteness of the paper was measured again, and the difference between the whiteness before printing and the whiteness after printing was determined.

[0057]

[Table 1]

Next, these electrophotographic photoreceptors were mounted on a photoreceptor characteristic measuring instrument, charged to a surface potential of -700 V, and then irradiated with light of 780 nm to obtain 13 μJ /
The potential (VL) at the exposure amount of cm 2, and the potential holding ratio (DDR) after being charged to −700 V and left for 5 seconds, 660 n
The residual potential (Vr) after the m LED light removal was measured. This measurement was performed under each environment. Table 2 shows the results.

[0059]

[Table 2]

The photosensitive member A1 of the present invention has a temperature / humidity of 5 ° C. /
In an environment of 10%, 25 ° C./50%, and 35 ° C./85%, compared with the photoconductors B1, B2, B3, and B4, 13
It can be seen that the difference between the potential and the residual potential at the exposure amount of μJ / cm 2 under each environment is small. Under each environment, the photoreceptor B3 having good image characteristics has a large environmental change compared with the photoreceptor of the embodiment, and has a problem of environmental dependency.

It can be seen that the photosensitive members B1 and B3 also have large environmental fluctuations. The photoconductor B4 is almost the same as the embodiment with respect to the environmental fluctuation of the electrical characteristics. However, considering that the potential holding ratio is slightly smaller than that of the photoconductors A1, B2, and B3, and that many small black spots are seen on a white background image in each environment in image characteristics, the photosensitive layer provided with the undercoat layer is considered. The body is considered preferred.

From the above results, it can be determined that the electrophotographic photoreceptor of the present invention has characteristics independent of various environments. This is because inorganic oxides such as titania generally have high water absorption, and are greatly affected by environmental changes, particularly humidity changes. For this reason, a method of reducing dependency on the environment by performing a surface treatment or the like is adopted. However, it has also been found that the surface treatment of the bulk is a factor that deteriorates the electrical characteristics, and as a result, it is considered that this leads to an increase in residual potential and the like.

On the other hand, organic substances such as perylene used in the present invention are generally hydrophobic, and are considered to be hardly affected by the above-mentioned changes in the environment, particularly, changes in humidity. Therefore, it is considered that no environmental difference is observed in various characteristics such as potential.

[0064]

The electrophotographic photoreceptor using the undercoat layer according to the present invention can provide excellent electrical and image properties in all environments from high temperature and high quality to low temperature and low humidity.

Continued on the front page F term (reference) 2H068 AA43 AA44 BA36 BB28 4J001 DA01 EB03 EB04 EB09 EB10 EB14 EC03 EC09 EC10 EC14 EC16 EE65E FB03 FC03 JA07

Claims (8)

[Claims] 1. An electrophotographic photoreceptor having an undercoat layer and a photosensitive layer provided on a conductive support in this order, wherein the undercoat layer contains an electron transporting organic compound and a polyamide resin. Electrophotographic photoreceptor. 2. The electrophotographic photoreceptor according to claim 1, wherein the polyamide resin contains an aliphatic diamine structural unit having 10 to 20 carbon atoms. 3. An electrophotographic photosensitive member in which an undercoat layer and a photosensitive layer are provided on a conductive support in this order, wherein the undercoat layer is represented by an electron transporting organic compound and the following general formula (I). An electrophotographic photosensitive member comprising a polyamide resin having a structural unit. Embedded image (In the general formula (I), R ^{1 to} R ¹⁶ each independently represent a hydrogen atom, a halogen atom, an alkyl group optionally substituted with a halogen atom, an alkoxy group optionally substituted with a halogen atom, Represents an alkylthio group which may be substituted with an atom, and R ¹⁷ and R ¹⁸ each independently represent
A hydrogen atom, an alkyl group which may be substituted with a halogen atom, and an alkoxy group which may be substituted with a halogen atom. ) 4. An aliphatic diamine structural unit having 10 to 20 carbon atoms in a total amount of 10 to 10 structural units constituting a polyamide resin.
The electrophotographic photosensitive member according to claim 2, wherein the content is 30%. 5. The electrophotographic photosensitive member according to claim 1, wherein the electron transporting organic compound is a perylene compound. 6. A perylene compound represented by the following general formula (II):
The electrophotographic photoreceptor according to claim 2, which is one of the compounds represented by (III) or (IV). Embedded image (In the general formula (II), R ¹⁹ and R ²⁰ each independently represent a hydrogen atom, an aryl group which may have a substituent, an alkyl group which may have a substituent, or a substituent. (In the formula (III), Ar ¹ and Ar ² each independently represent an aromatic hydrocarbon ring which may have a substituent.) (General In the formula (IV), Ar ³ and Ar ⁴ each independently represent an aromatic hydrocarbon ring which may have a substituent.) 7. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer is formed by laminating a charge generation layer and a charge transfer layer. 8. The electrophotographic photosensitive member according to claim 1, wherein the undercoat layer does not contain a metal oxide.