JP2000075518A - Electrophotographic photoreceptor - Google Patents

Abstract

(57) [Problem] To provide an electrophotographic photoreceptor excellent in sensitivity and residual potential. SOLUTION: The photosensitive layer formed on the conductive support,
An electrophotographic photoconductor containing an enamine compound represented by the following general formula (1). Embedded image (R ^{1 to} R ⁴ are an alkyl group, an aryl group, an aralkyl group,
Cycloalkyl group, heterocyclic group or fused polycyclic group, Ar ¹ to
Ar ⁴ is a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, a heterocyclic group or a condensed polycyclic group, and X is -CH = CH-Y
-CH = CH- and the like. Y is a divalent alkylene group, an arylene group, a heterocyclic group or a condensed polycyclic group)

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor, and more particularly to a very sensitive and high-performance electrophotographic photoreceptor having a photosensitive layer containing an organic photoconductive substance. It is.

[0002]

2. Description of the Related Art Conventionally, the photosensitive layer of an electrophotographic photoreceptor has
Inorganic photoconductive substances such as selenium, cadmium sulfide, and zinc oxide have been widely used. However, selenium,
Cadmium sulfide must be recovered after use, and selenium has poor heat resistance, cadmium sulfide and zinc oxide have poor moisture resistance, and zinc oxide has poor printing durability. The development of various photosensitive materials is underway. In recent years, research on using an organic photoconductive substance for a photosensitive layer of a photoconductor for electrophotography has been advanced, and a part thereof has been put to practical use.

Organic photoconductive materials are lighter in weight, easier to form films, easier to produce a photoreceptor, and can produce a transparent photoreceptor depending on the type, as compared to inorganic ones. And has the advantage that the material is pollution-free.

[0004] Recently, a so-called function-separated type photoreceptor, in which a charge carrier generation function and a charge transfer function are shared by different compounds, is effective for increasing the sensitivity. In addition, this function-separated type organic photoconductor has been put to practical use.

In this function-separated type organic photoreceptor, as a charge carrier transporting medium, a polymer photoconductive compound such as polyvinyl carbazole is used, and a low molecular weight photoconductive compound is dispersed and dissolved in a binder polymer. May be used.

[0006] Among these, particularly when an organic low molecular weight photoconductive compound is used, by selecting a polymer having excellent film properties, flexibility, adhesion and the like as a binder, mechanical properties can be easily achieved. There is an advantage that a photosensitive member having excellent characteristics can be obtained (for example, see Japanese Patent Application Laid-Open No. 63-26916).
No. 0, Japanese Patent Publication No. 3-39306, Japanese Patent Publication No. 4-5
No. 3308).

[0007]

However, a more sensitive electrophotographic photoreceptor using a low molecular weight photoconductive compound is desired.

The present invention solves the above-mentioned conventional problems and provides an electrophotographic photosensitive member using a low-molecular-weight photoconductive compound as a charge transporting agent. It is an object of the present invention to provide an electrophotographic photoreceptor having no problem of potential rise.

[0009]

Means for Solving the Problems The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having a photosensitive layer formed on a conductive substrate, wherein the photosensitive layer is represented by the following general formula (1). Characterized in that it contains an enamine-based compound.

[0010]

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(In the general formula (1), R ¹ , R ² , R ³ and R ⁴
Is an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a cycloalkyl group which may have a substituent,
Represents a heterocyclic group which may have a substituent or a condensed polycyclic group which may have a substituent, which may be the same or different from each other; Ar ¹ , Ar ² , Ar ³ and Ar ⁴ is a hydrogen atom, an alkyl group which may have a substituent,
Represents an aralkyl group which may have a substituent, an aryl group which may have a substituent, a heterocyclic group which may have a substituent, or a condensed polycyclic group which may have a substituent. these may be the same or different from each other; X ^{is, -CR 5 = CR 6 - -CR} 7 = CR 8 -CR 9 = CR 10 - or ^{-CR 11 = CR 12 -Y-CR} 13 = CR 14 R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ ,
R ¹² , R ¹³ and R ¹⁴ each represent a hydrogen atom, an alkyl group optionally having a substituent, an aralkyl group optionally having a substituent, an aryl group optionally having a substituent, Represents a heterocyclic group which may have a substituent or a condensed polycyclic group which may have a substituent. These may be the same or different from each other, and Y represents a group which may have a substituent. A divalent alkylene group, a divalent arylene group which may have a substituent, a divalent heterocyclic group which may have a substituent or a divalent fused polycyclic group which may have a substituent. Represent. The enamine-based compound represented by the general formula (1) exhibits extremely excellent performance as an organic photoconductive compound, and particularly, when used as a charge transport agent, has high sensitivity and excellent durability. You can get the body.

The electrophotographic photoreceptor of the present invention has the following structure. The photosensitive layer contains a charge generating agent and a charge transporting agent, and contains the enamine-based compound represented by the general formula (1) as the charge transporting agent. The photosensitive layer has a charge transporting layer containing a charge transporting agent, and a charge generating layer containing a charge generating agent and a binder resin, and the enamine represented by the general formula (1) as a charge transporting agent in the charge transporting layer. It contains a system compound. In this case, the charge transport layer preferably contains a charge transport agent and a binder resin.

In the present invention, the charge generator is preferably an azo pigment having a coupler component represented by the general formula (A) in a molecule or a phthalocyanine compound.

[0014]

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(In the general formula (A), B represents a nitrogen-containing divalent heterocyclic group or a divalent aromatic hydrocarbon group, which may have a substituent.)

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

First, the enamine-based compound represented by the general formula (1) contained in the photosensitive layer of the electrophotographic photosensitive member of the present invention will be described.

In the general formula (1), R ¹ , R ² , R
³ and R ⁴ are each an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, and a hexyl group; an aralkyl group such as a benzyl group, a naphthylmethyl group and a phenethyl group; an aryl group such as a phenyl group and a naphthyl group; A cycloalkyl group such as a cyclopentyl group or a cyclohexyl group; a heterocyclic group such as a thienyl group, a furyl group, or a pyridyl group; a fused polycyclic group such as a pyrenyl group, an anthracenyl group, or a fluorenyl group; Fused polycyclic groups are preferred. These may be the same or different from each other, and they may have a substituent. Examples of the substituent include a hydroxyl group; a halogen atom such as a chlorine atom, a bromine atom and an iodine atom; an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group and a hexyl group; an alkoxy group such as a methoxy group, an ethoxy group and a butoxy group. Allyl group; Allyloxy group; Aralkyl groups such as benzyl group, naphthylmethyl group, and phenethyl group; Aryloxy groups such as phenoxy group and toloxy group; Aralkyloxy groups such as benzyloxy group and phenethyloxy group; Phenyl group and naphthyl group Heteroaryl groups such as thienyl group and furyl group; arylvinyl groups such as styryl group and naphthylvinyl group; dialkylamino groups such as dimethylamino group and diethylamino group; diphenylamino group and dinaphthylamino group Diarylamino group; dibenzylamino group, diphenethylamino group, etc. A diaralkylamino group; a diheterocyclic amino group such as a dithienylamino group or a difurylamino group; a diallylamino group; a disubstituted amino group obtained by combining the above amino groups; a nitro group; an acyl group such as an acetyl group or a benzoyl group. No.

Ar ¹ , Ar ² , Ar ³ and Ar ⁴ are each a hydrogen atom; an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group and a hexyl group; a benzyl group, a naphthylmethyl group, a phenethyl group and the like. An aralkyl group; an aryl group such as a phenyl group and a naphthyl group; a heterocyclic group such as a thienyl group, a furyl group and a pyridyl group; a condensed polycyclic group such as a pyrenyl group, an anthracenyl group and a fluorenyl group; A hydrogen atom, an alkyl group, and an aryl group are preferred. These may be the same or different from each other,
These may have a substituent. Examples of the substituent include those described above as examples of the substituent such as R ¹ .

[0020] X ^{is, -CR 5 = CR 6 - -CR} 7 = CR 8 -CR 9 = CR 10 - or ^{-CR 11 = CR 12 -Y-CR} 13 = CR 14 - and is, R ^5, R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ ,
R ¹² , R ¹³ and R ¹⁴ are each a hydrogen atom; an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group and a hexyl group; an aralkyl group such as a benzyl group, a naphthylmethyl group and a phenethyl group; , An aryl group such as a naphthyl group; a heterocyclic group such as a thienyl group, a furyl group, a pyridyl group; a condensed polycyclic group such as a pyrenyl group, an anthracenyl group, or a fluorenyl group;
Alkyl groups and aryl groups are preferred. These may be the same or different from each other, and they may have a substituent. Examples of the substituent include those described above as examples of the substituent such as R ¹ .

Y is a divalent alkylene group such as a methylene group, an ethylene group, a propylene group or a butylene group; a divalent arylene group such as a phenylene group, a naphthylene group or a biphenylene group; a thienylene group, a furylene group, a pyridylene group or the like. Represents a divalent condensed polycyclic group such as an anthracenylene group, a pyrenylene group, or a fluorenylene group, and among these, an arylene group and a condensed polycyclic group are particularly preferable. These may be the same or different from each other, and they may have a substituent. Examples of the substituent include those described above as examples of the substituent such as R ¹ .

The following are typical specific examples of the enamine-based compound represented by the general formula (1). The compounds shown below are examples of the enamine-based compound according to the present invention and do not limit the present invention. It does not do.

[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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The enamine compound represented by the general formula (1) can be produced by a known method. For example, it can be produced by a method in which a known enamine-based compound is carbonylated into a carbonyl compound and then condensed reductively, or subjected to a condensation reaction with a phosphonic acid diester or a Wittig reagent to obtain a target compound.

This manufacturing method will be described below. The following general formulas (2), (3), (4), (5A), (5
In B), (6A) and (6B), R ^{1 to} R ⁵ , A
r ¹ , Ar ² , X and the like have the same meanings as in the general formula (1).

[Carbonylation] When R ⁵ , R ⁷ , R ¹¹ = hydrogen atom, an enamine compound represented by the following general formula (2) is converted to N, N in the presence of phosphorus oxychloride. N-dimethylformamide, N
-Aldehyde represented by the general formula (3) is obtained by reacting with a formylating agent such as methylformanilide.

[0031]

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In this case, a large excess of the formylating agent can be used as a reaction solvent, but a solvent inert to the reaction such as o-dichlorobenzene or benzene can also be used.

When R ⁵ , R ⁷ , R ¹¹ Ｒhydrogen,
The enamine-based compound represented by the general formula (2) is converted to a compound represented by the general formula Cl- in the presence of a Lewis acid such as aluminum chloride, iron chloride or zinc chloride in a solvent such as nitrobenzene, dichloromethane or carbon tetrachloride. by reaction with an acid chloride represented by CO-R ^5, to obtain a ketone compound represented by the general formula (4).

[0034]

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[Condensation reaction] In the case of a reductive condensation reaction, a carbonyl compound represented by the general formula (4) is converted into a known organic solvent inert to a reaction such as tetrahydrofuran or dioxane as shown below.
Titanium trichloride and potassium, titanium trichloride and lithium, titanium trichloride and lithium aluminum hydride, titanium trichloride and magnesium, titanium tetrachloride and lithium aluminum hydride, titanium tetrachloride and zinc, tungsten hexachloride and lithium aluminum hydride , React with a reagent prepared from tungsten hexachloride and butyllithium, etc. at room temperature or under heating, react with triethyl phosphite under heating, or react under heating with a reagent prepared from chlorodiphenylphosphine and sodium hydride it by the general formula ^{(1) (X: -CR 5} = CR 6 -) represented by can be obtained enamine compound.

[0036]

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In order to suppress side reactions in this reaction, pyridine, triethylamine, tri-n-butylamine, 1,8-bis (dimethylamino)
A tertiary amine such as naphthalene may be added.

In this reaction, a symmetric enamine compound can be obtained by using one kind of carbonyl compound, and an asymmetric enamine compound can be obtained by using two or more kinds of carbonyl compounds.

At this time, at the double bond, any one of a cis-form, a trans-form, and a mixture of the cis-form and the trans-form is obtained. Represents either the trans form or a mixture of the cis form and the trans form.)

In the case of the Wittig reaction, the carbonyl compound represented by the general formula (4) is converted to the following general formula (5A), (5B), (6A) or (6B) (in these general formulas) R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ represent an alkyl group, and Z represents a halogen atom.), A tetrahydrofuran, 1,2-dimethoxyethane, N, N- By reacting in a solvent such as dimethylformamide in the presence of a base such as potassium alkoxide, sodium hydride or sodium alkoxide, the compound represented by the general formula (1)
^{(X: -CR 7 = CR 8} -CR 9 = CR 10 -, - CR 11 =
^{CR 12 -Y-CR 13 = CR} 14 -) represented by can be obtained enamine compound.

[0041]

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Also in this reaction, a symmetric enamine compound can be obtained by using one kind of carbonyl compound, and an asymmetric enamine compound can be obtained by using two or more kinds of carbonyl compounds.

At this time, at the double bond, any one of a cis-form, a trans-form, and a mixture of the cis-form and the trans-form is obtained. Represents either the trans form or a mixture of the cis form and the trans form.)

In the above reaction, depending on the case, after each step or after completion of all the steps, purification may be carried out by a known method such as recrystallization purification or column purification, whereby a highly purified product may be obtained. It is possible.

The electrophotographic photoreceptor of the present invention has a photosensitive layer containing one or more of such enamine-based compounds.

In general, the form of the photosensitive layer (photoconductive layer) of the electrophotographic photoreceptor is a laminated type in which a charge generation layer and a charge transport layer are laminated in this order or reversely, or a charge transport agent (charge transport medium). ) Are known in various forms such as a so-called dispersion type in which particles of a charge generating agent (charge generating substance) are dispersed, and the photosensitive layer of the electrophotographic photoreceptor of the present invention has any of these forms. May be.

The laminated photosensitive layer includes, for example, a charge transporting layer composed of an enamine compound as a charge transporting agent and a binder, a charge generating agent that generates charge carriers with extremely high efficiency when absorbing light, A photosensitive layer in which an agent and a charge generation layer comprising a binder are laminated.

In such a laminated photoreceptor, a charge generation layer is generally formed by directly depositing a charge generation agent on a conductive support or by applying the charge generation agent as a dispersion with a binder. By casting the enamine-based compound by casting an organic solvent solution containing the enamine-based compound, or dissolving or dispersing the enamine-based compound together with a binder and other low-molecular-weight compounds to prepare a coating solution and coating the enamine-based compound. It can be produced by forming a charge transport layer containing a charge transport agent. Note that, as described above, the order of lamination of the charge generation layer and the charge transport layer in the laminated photoconductor may be reversed.

The single-layer type photosensitive layer includes, for example, a photosensitive layer to which an enamine compound and, if necessary, a dye or an electron-withdrawing compound serving as a sensitizer are added, or a charge generator and an enamine compound. And a photosensitive layer dispersed in an appropriate binder.

Such a single-layer type photoreceptor is manufactured by applying a coating solution in which a charge generating agent and an enamine compound as a charge transporting agent are dispersed or dissolved in a binder onto a conductive support. be able to.

In the present invention, the enamine compound is
When used in a charge transport layer of a laminated photosensitive layer composed of two layers, a charge generation layer and a charge transport layer (charge transfer layer), the sensitivity is particularly high, the residual potential is small, and the surface potential when used repeatedly. Of a photosensitive member having excellent durability and less fluctuation of the toner, lowering of sensitivity, accumulation of residual potential, and the like are preferable.

The charge generator used together with the enamine compound according to the present invention includes selenium, selenium-tellurium alloy,
Inorganic photoconductive particles such as selenium-arsenic alloy, cadmium sulfide, and amorphous silicon; metal-free phthalocyanine, metal-containing phthalocyanine, perinone pigment, thioindigo, quinacridone, perylene pigment, anthraquinone pigment, azo pigment, bisazo pigment, Organic photoconductive particles such as trisazo pigments, tetrakis azo pigments, and cyanine pigments are exemplified. Also, various organic pigments and dyes such as polycyclic quinone, pyrylium salt, thiopyrylium salt, indigo, anthantrone, and pyranthrone can be used. Among them, in particular, metal-free phthalocyanine, or a metal such as copper, indium chloride, gallium chloride, tin, oxytitanium, zinc, vanadium or an oxide thereof,
Azo pigments such as phthalocyanines, monoazo, bisazo, trisazo and polyazos, to which chlorides are coordinated, are preferred.

In particular, when an enamine-based compound is combined with a metal-containing phthalocyanine represented by the following formula (1) or an azo pigment having a coupler component represented by the following general formula (A) in the molecule, the sensitivity to laser light is improved, An excellent photoconductor having a small residual potential can be obtained.

The Bragg angle of the X-ray diffraction spectrum (2
θ ± 0.2 °) Oxytitanium phthalocyanine showing diffraction peaks at 9.7 °, 14.2 °, and 27.3 ° Bragg angle of X-ray diffraction spectrum (2θ ± 0.2
°) Oxytitanium phthalocyanine showing diffraction peaks at 9.3 °, 13.2 °, 26.2 °, and 27.1 ° Bragg angle of X-ray diffraction spectrum (2θ ± 0.3
゜) 9.2 °, 14.1 °, 15.3 °, 19.7 °,
Dihydroxysilicon phthalocyanine having a peak at 27.1 °

[0055]

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Hereinafter, the structure of the electrophotographic photosensitive member of the present invention will be described in detail.

In the present invention, as the conductive support on which the photosensitive layer is formed, any one which has been used for a known electrophotographic photosensitive member can be used. Specifically, aluminum, stainless steel, copper, a drum made of a metal material such as nickel, a sheet or a laminate of these metal foils,
Aluminum, copper, palladium on the deposit or surface
Examples include an insulating support such as a polyester film or paper provided with a conductive layer such as tin oxide or indium oxide. Further, plastic films, plastic drums, paper, paper tubes, and the like, which have been subjected to conductive treatment by applying a conductive substance such as metal powder, carbon black, copper iodide, and a polymer electrolyte together with a suitable binder, may be used. In addition, plastic sheets and drums provided with conductivity by blending conductive materials such as metal powder, carbon black, and carbon fiber, and plastics that have been conductively treated with conductive metal oxides such as tin oxide and indium oxide Examples include films and belts.

Among these, a particularly preferred support is an endless pipe made of metal such as aluminum.

The single-layer type electrophotographic photoreceptor is prepared by dissolving the enamine compound according to the present invention in an appropriate solvent and, if necessary, adding an appropriate charge generator, sensitizing dye, enamine compound and charge transfer. An electron-withdrawing compound that forms a complex, another charge transporting agent, or a known plasticizer, a cross-linking agent, or a residual-potential-suppressing agent for improving film forming properties, flexibility, mechanical strength, and the like. Additives, dispersing aids for improving dispersion stability, leveling agents for improving coating properties, fluidity-imparting agents, surfactants such as silicone oils, fluorine-based oils, pigments, and other well-known additives The obtained coating solution is coated on the conductive support described above, dried, and usually several μm.
It can be produced by forming a photosensitive layer having a thickness of m to several tens of μm, preferably 10 to 40 μm, particularly preferably 25 μm or more.

In the case of a dispersion type photosensitive layer in which particles of a charge generating agent are dispersed in a single photosensitive layer, the particle size of the charge generating agent must be sufficiently small, preferably 1 μm or less.
More preferably, the thickness is 0.5 μm or less. The amount of the charge generating agent dispersed in the photosensitive layer is, for example, in the range of 0.5 to 50% by weight. If the content is too small, sufficient sensitivity cannot be obtained. There are adverse effects such as a decrease in sensitivity and a decrease in sensitivity. The more preferable content of the charge generating agent is 1 to 20% by weight, and the thickness of the dispersion type photosensitive layer is usually 5 to 20% by weight.
It is 50 μm, preferably 10 to 45 μm.

The binder resin used as the matrix is preferably a polymer which has good compatibility with the enamine compound and does not undergo phase separation after the formation of a coating film. For example, styrene, vinyl acetate, vinyl chloride,
Polymers and copolymers of vinyl compounds such as acrylic acid esters, methacrylic acid esters, butadiene, polyvinyl acetal, polycarbonate, polyester, polyester carbonate, polysulfone, polyimide, polyphenylene oxide, polyurethane, cellulose ester, cellulose ether, phenoxy resin, silicon Various resins such as epoxy resin and epoxy resin,
These partially crosslinked cured products can also be used. The amount of the binder to be used is generally 0.5 to 30 times by weight, preferably 0.7 to 10 times by weight, based on the enamine compound.

In the case of a laminated electrophotographic photoreceptor comprising two layers of a charge generation layer and a charge transport layer, the above-mentioned coating solution for forming a single-layer photosensitive layer is applied on the charge generation layer, or It can be manufactured by forming a charge generation layer on a charge transport layer obtained by applying this coating solution. In this case, the enamine-based compound-containing coating solution for forming the charge transport layer may have the above-described composition, but the photoconductive particles, the dye, the electron-withdrawing compound, and the like are removed or added in a small amount. good.

In this case, the charge generating layer is a coating solution obtained by dissolving or dispersing the above-mentioned photoconductive particles and, if necessary, a solvent such as a binder or other organic photoconductive substance, a dye or an electron-withdrawing compound. And a layer in which the photoconductive particles are formed by means such as vapor deposition. The charge transport layer in the case of the laminated photosensitive layer may contain various additives such as an antioxidant and a sensitizer, and other charge transport agents, if necessary. The thickness of the charge transport layer is usually 10 to 60 μm, preferably 10 to 45 μm, and more preferably 25 to 40 μm.

On the other hand, the charge generating layer is coated with a coating solution obtained by dissolving or dispersing the charge generating agent and, if necessary, a binder, another organic photoconductive substance, a dye or an electron-withdrawing compound in a solvent. It can be formed by drying or by directly depositing the charge generating agent by means such as vapor deposition.

When the charge generation layer in the laminated photosensitive layer is formed by a coating method, fine particles of the charge generation agent may be formed by, for example, polyester resin, polyvinyl acetate, polyester, polycarbonate, polyvinyl acetoacetal, or the like.
It may be formed as a dispersion layer in a form bound by various binder resins such as polyvinyl propional, polyvinyl butyral, phenoxy resin, epoxy resin, urethane resin, cellulose ester and cellulose ether. Further, as the binder resin, styrene, vinyl acetate,
Polymers and copolymers of vinyl compounds such as vinyl chloride, acrylic acid esters, methacrylic acid esters, vinyl alcohol and ethyl vinyl ether, polyamides, silicon resins and the like can also be used.

In this case, the use ratio of the charge generating agent is usually 20 to 2,000 parts by weight, preferably 30 to 500 parts by weight, more preferably 33 to 500 parts by weight, based on 100 parts by weight of the binder resin. The thickness of the charge generation layer is generally 0.05 to 5 μm, preferably 0.1 to 2 μm, and more preferably 0.15 to 0.8 μm.

Further, the charge generation layer may contain various additives such as a leveling agent, an antioxidant, and a sensitizer for improving coating properties, if necessary.

As described above, the charge generation layer may be a vapor-deposited film of the charge generation agent.

In the case of such a laminated electrophotographic photoreceptor, the charge transfer layer is usually formed on the charge transfer layer, but the charge transfer layer may be formed on the charge transfer layer.

In the photosensitive layer of the electrophotographic photoreceptor of the present invention, phthalic acid esters, phosphoric acid, and the like are used as plasticizers to be added to the coating solution in order to improve film forming property, flexibility and mechanical strength. Examples include esters, epoxy compounds, chlorinated paraffins, chlorinated fatty acid esters, and aromatic compounds such as methylnaphthalene.

Examples of the dyes that may be added include, for example, triphenylmethane dyes such as methyl violet, brilliant green and crystal violet, thiazine dyes such as methylene blue, quinone dyes such as quinizarin, cyanine dyes and pyrylium salts. Thiapyrylium salts, benzopyrylium salts and the like.

Examples of the electron-withdrawing compound which forms a charge-transfer complex with an enamine compound include, for example, chloranil, 2,3-dichloro-1,4-naphthoquinone, 1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone Quinones such as, 2-chloroanthraquinone and phenanthrenequinone; aldehydes such as 4-nitrobenzaldehyde; 9-benzoylanthracene, indandione, 3,5-dinitrobenzophenone, 2,4,7-
Ketones such as trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, 3,3 ', 5,5'-tetranitrobenzophenone; acid anhydrides such as phthalic anhydride and 4-chloronaphthalic anhydride; Cyano compounds such as tetracyanoethylene, terephthalalmalononitrile, 9-anthrylmethylidenemalononitrile, 4-nitrobenzalmalonenitrile, 4- (p-nitrobenzoyloxy) benzalmalononitrile; 3-benzalphthalide, 3- (Α-cyano-p-nitrobenzal) phthalide, 3- (α-cyano-p-nitrobenzal) -4,
Electron-withdrawing compounds such as phthalides such as 5,6,7-tetrachlorophthalide.

Solvents for preparing a coating solution include ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; N, N-dimethylformamide, acetonitrile; N-methylpyrrolidone,
Aprotic polar solvents such as dimethyl sulfoxide; esters such as ethyl acetate, methyl formate, and methyl cellosolve acetate; and solvents dissolving enamine-based compounds such as chlorinated hydrocarbons such as dichloroethane and chloroform and binders.

In the present invention, together with the enamine-based compound, other known arylamine compounds and hydrazone compounds having excellent performance as an organic photoconductor are added to the photosensitive layer.
A stilbene compound may be mixed.

The photosensitive layer of the electrophotographic photoreceptor of the present invention may contain other well-known additives in order to improve electric characteristics or durability in repeated use. For this purpose, the additives to be added to the coating solution include phenolic compounds, amine compounds, organic phosphorus compounds, organic sulfur compounds, and the like. Specific examples of the phenolic compound, the amine compound, the organic phosphorus compound, and the organic sulfur compound include the following.

[Phenol compounds] dibutylhydroxytoluene, 2,2'-methylenebis (6-t-butyl-4-methylphenol), 4,4'-butylidenebis (6-t-butyl-3-methylphenol), 4,4 '
-Thiobis (6-tert-butyl-3-methylphenol), 2,2'-butylidenebis (6-tert-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'-thioethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 1,6-hexanediolbis [3- (3 5-di-t-butyl-4-hydroxyphenyl) propionate], butylhydroxyanisole, dibutylhydroxyanisole, 1- [2-
{(3,5-di-butyl-4-hydroxyphenyl) propionyloxy} ethyl] -4- [3- (3,5-di-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6 6-tetramethylpiperidyl, 2,
4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-
Triazine, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3-t-butyl-5
-Methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 1- [2- {3- (3,5-di-t-
Butyl-4-hydroxyphenyl) propionyloxy {ethyl] -4- {3- (3,5-di-t-butyl-
4-hydroxyphenyl) propionyloxy {-2,
2,6,6-tetramethylpiperidine, octadecyl-
3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate and the like.

[Amine compound] 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-butyl-p-phenylenediamine, tribenzylamine and the like.

[Organic phosphorus compound] Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine,
Tri (2,4-dibutylphenoxy) phosphine, tris (2,4-di-t-butylphenyl) phosphite and the like.

[Organic sulfur compound] Dilauryl-3,
3'-thiodipropionate, distearyl-3,3 '
-Thiodipropionate, ditetradecyl-3,3'-
Thiodipropionate and the like.

Examples of the method of applying the photosensitive layer include a spray coating method, a spiral coating method, a ring coating method, and a dip coating method.

As the spray coating method, air spray,
There are airless spray, electrostatic air spray, electrostatic airless spray, rotary atomizing electrostatic spray, hot spray, hot airless spray, etc., considering the degree of atomization and adhesion efficiency to obtain a uniform film thickness. In the rotary atomization type electrostatic spray, by the transport method disclosed in the re-published Hei 1-805198, that is, by transporting the cylindrical work continuously while rotating the cylindrical work without spacing in the axial direction, It is possible to obtain an electrophotographic photoreceptor excellent in uniformity of film thickness with high deposition efficiency overall.

The spiral coating method is disclosed in
A method using a liquid coating machine or a curtain coating machine disclosed in Japanese Patent Application Publication No. 119651, a method for continuously flying paint in a streak form from a fine opening disclosed in Japanese Patent Application Laid-Open No. 1-231966, There is a method using a multi-nozzle body disclosed in Japanese Unexamined Patent Publication No. 3-193161.

In the case of the dip coating method, first, the total solid content is preferably 25 to 40% by weight and the viscosity is usually 50 to 300 centipoise using the enamine compound, binder, solvent and the like according to the present invention. Preferably 100-
A 200 centipoise coating solution for forming a charge transport layer is prepared. Here, the viscosity of the coating liquid is substantially determined by the type and molecular weight of the binder, but if the molecular weight is excessively low, the mechanical strength of the binder itself is reduced,
It is preferable to use a binder having a molecular weight that does not impair this. Then, a charge transport layer is formed by a dip coating method using the prepared coating liquid, and then the coating film is dried.

In the present invention, the drying after the application of the coating solution is performed by adjusting the drying temperature and time so that the coating film can be sufficiently dried. The drying temperature is usually 100 to 250 ° C, preferably 110 to 170 ° C, more preferably 120 to 140 ° C.
It is in the range of ° C. As a drying method, a hot air dryer, a steam dryer, an infrared dryer, a far infrared dryer, or the like can be used.

The electrophotographic photoreceptor of the present invention having the photosensitive layer formed on the conductive support as described above may further include, if necessary, an intermediate layer such as a barrier layer, an adhesive layer, or a blocking layer. Needless to say, a layer such as an insulating layer or a protective layer for improving electric characteristics and mechanical characteristics may be formed. Here, as the barrier layer and the intermediate layer, for example, an anodized aluminum film, aluminum oxide, an inorganic layer such as aluminum hydroxide, polyvinyl alcohol,
Organic layers such as casein, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, and polyamide are used. Furthermore, an overcoat layer mainly composed of a conventionally known thermoplastic or thermosetting polymer may be provided as the outermost surface layer. As a forming method of each layer, a known method such as sequentially applying a coating solution obtained by dissolving or dispersing a substance to be contained in a layer in a solvent can be applied.

[0086]

EXAMPLES The present invention will be described more specifically with reference to production examples and examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Production Example 1 An enamine compound according to the present invention was produced.

[Carbonylation] To a solution of 3.1 g of an enamine compound represented by the following structural formula in 21 ml of N, N-dimethylformamide was added phosphorus oxychloride (1.6 ml) with stirring at room temperature. 1 hour 30 at the same temperature
Minutes. Thereafter, the reaction solution was poured into distilled water (50 ml), extracted and concentrated by a conventional method to obtain yellow crystals.
1 g (melting point: 170-172 ° C.) was obtained.

[0089]

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The obtained compound was analyzed by mass spectrometry and ¹ H
Nuclear magnetic resonance spectroscopy revealed that the compound was a carbonyl compound having the following structural formula.

[0091]

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(Results of Mass Spectrometry) MW = 375 M + = 375 as C ₂₇ H ₂₁ ON [Condensation reaction] 5.0 g of the carbonyl compound synthesized by the above carbonylation and 2.9 g of Wittig reagent having the following structural formula
In a solution of tetrahydrofuran (50 ml) at room temperature (25
Under stirring, 3.9 g of a methanol solution of sodium methoxide (28% by weight) was added, and the mixture was stirred at the same temperature for 50 hours. Thereafter, 1.6 g of Wittig reagent was further added.
Methanol solution of sodium methoxide (28% by weight)
2.0 g was added, and the mixture was stirred at room temperature for 13 hours. Thereafter, a reaction treatment and a purification treatment were carried out by a conventional method, and 0.8 g of an orange crystal was obtained.
(Melting point: 165-175 ° C) was obtained.

[0093]

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This compound was found to be an enamine-based compound of the present invention having the following structural formula by mass spectrometry and infrared absorption spectrum measurement.

[0095]

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(Mass Spectrometry Results) C ₆₂ H ₄₈ N ₂ MW = 820 M + = 820 (Infrared Absorption Spectra Measurement Results) FIG. 1 shows the results.

Example 1 An electrophotographic photoreceptor was produced using the enamine-based compound produced in Production Example 1 as a charge transporting agent.

1.0 part by weight of a naphthalic acid-based bisazo pigment represented by the following structural formula was added to 14 parts by weight of dimethoxyethane, and the mixture was dispersed with a sand grinder. Then, 14 parts by weight of dimethoxyethane and 4-methoxy-4- Methyl-2-
14 parts by weight of pentanone (manufactured by Mitsubishi Chemical Corporation) was added for dilution. Polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd.), trade name "Denka Butyral"# 600
0-C) 0.5 part by weight and a phenoxy resin (trade name “UCAR” (registered trademark) manufactured by Union Carbide Co., Ltd.)
PKHH) was mixed with a solution prepared by dissolving 0.5 part by weight of dimethoxyethane in a mixed solution of 6 parts by weight of dimethoxyethane and 6 parts by weight of 4-methoxy-4-methyl-2-pentanone to obtain a dispersion.
The weight of the dispersion after drying was 0.4 g on an aluminum deposition layer deposited on a polyester film having a thickness of 75 μm.
/ M ² , and then dried to form a charge generation layer.

[0099]

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On the charge generation layer, a coating solution prepared by dissolving 110 parts by weight of the enamine compound prepared in Preparation Example 1 and 100 parts by weight of a polycarbonate resin represented by the following structural formula in a mixed solution of 900 parts by weight of tetrahydrofuran was applied. After drying, a charge transport layer having a thickness of 29 μm was formed.

[0101]

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The sensitivity (half-exposure amount) of the thus obtained electrophotographic photosensitive member having the photosensitive layer composed of two layers was 1.558 lux · sec. The half-exposure amount is measured by first charging the photoreceptor to -700 V in a dark place, then exposing it to 2 lux white light, and measuring the exposure amount required for the surface potential to attenuate from -550 V to -275 V. I asked for it. When the surface potential when the exposure time was set to 10 seconds was measured as a residual potential, it was -16 V.

Example 2 In Example 1, instead of the bisazo naphthalate pigment, the X-ray diffraction spectrum showed a Bragg angle (2θ ±
0.2 °) 9.3 °, 13.2 °, 26.2 °, 27.
A charge generation layer was formed in the same manner except that an oxytitanium phthalocyanine pigment showing a main diffraction peak at 1 ° was used. Thereafter, a coating solution obtained by dissolving 70 parts by weight of the enamine-based compound prepared in Preparation Example 1 and 100 parts by weight of a polycarbonate resin represented by the following structural formula in a mixed solution of 900 parts by weight of tetrahydrofuran is applied on the charge generation layer, and dried. Thus, a charge transport layer having a thickness of 21 μm was formed.

[0104]

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The thus obtained electrophotographic photosensitive member having the two-layered photosensitive layer was irradiated with 780 nm light (light amount 500
nW), and the half-exposure amount was measured.
It was 51 μJ / cm ² . The residual potential obtained in the same manner as in Example 1 was -16 V.

[0106]

As described in detail above, the photoreceptor for electrophotography of the present invention has a very high sensitivity, a small residual potential which causes fogging, and in particular, has a small amount of light fatigue. Laser printers and liquid crystal shutters that are not only suitable for PPC, but also require stable performance and reliability, as well as low residual potential accumulation and small fluctuations in surface potential and sensitivity due to Printer,
It is a high-performance electrophotographic photoconductor suitable for a photoconductor for a printer such as an LED printer.

[Brief description of the drawings]

FIG. 1 is an infrared absorption spectrum of an enamine compound according to the present invention produced in Production Example 1.

Claims (6)

[Claims] 1. An electrophotographic photosensitive member having a photosensitive layer formed on a conductive substrate, wherein the photosensitive layer contains an enamine-based compound represented by the following general formula (1). Photoreceptor. Embedded image (In the general formula (1), R ¹ , R ² , R ³ and R ⁴ each have an alkyl group which may have a substituent, an aralkyl group which may have a substituent, and a substituent. Or an optionally substituted aryl group, a cycloalkyl group optionally having a substituent, a heterocyclic group optionally having a substituent, or a condensed polycyclic group optionally having a substituent. Ar ¹ , Ar ² , Ar ³ and Ar ⁴ may be the same or different;
A hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a heterocyclic group which may have a substituent, or X represents a condensed polycyclic group which may have a substituent, which may be the same or different; X represents -CR ⁵ = CR ⁶ -CR ⁷ = CR ⁸ -CR ⁹ = CR ¹⁰ -or ^{-CR 11 = CR 12 -Y-CR} 13 = CR 14 - and ^{is, R 5, R 6, R} 7, R 8, R 9, R 10, R 11,
R ¹² , R ¹³ and R ¹⁴ each represent a hydrogen atom, an alkyl group optionally having a substituent, an aralkyl group optionally having a substituent, an aryl group optionally having a substituent, Represents a heterocyclic group which may have a substituent or a condensed polycyclic group which may have a substituent. These may be the same or different from each other, and Y represents a group which may have a substituent. A divalent alkylene group, a divalent arylene group which may have a substituent, a divalent heterocyclic group which may have a substituent or a divalent fused polycyclic group which may have a substituent. Represent. ) 2. The photosensitive layer according to claim 1, wherein the photosensitive layer contains a charge generating agent and a charge transporting agent, and the charge transporting agent contains an enamine compound represented by the general formula (1). 2. The electrophotographic photoreceptor according to claim 1. 3. The photosensitive layer has a charge transporting layer containing a charge transporting agent and a charge generating layer containing a charge generating agent and a binder resin, wherein the charge transporting agent in the charge transporting layer has the general formula (1) 2. The electrophotographic photoconductor according to claim 1, further comprising an enamine compound represented by the formula: 4. The electrophotographic photoconductor according to claim 3, wherein the charge transport layer contains a charge transport agent and a binder resin. 5. The photosensitive layer according to claim 1, wherein an azo pigment having a coupler component represented by the general formula (A) in a molecule is contained as a charge generating agent in the photosensitive layer. Item 2. An electrophotographic photoreceptor for electronic use according to item 1. Embedded image (In the general formula (A), B represents a nitrogen-containing divalent heterocyclic group or a divalent aromatic hydrocarbon group, which may have a substituent.) 6. The photoconductor for electrophotography according to claim 1, wherein the photoconductive layer contains a phthalocyanine compound as a charge generating agent.