JPH10260540A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor high in sensitivity and low in residual potential by incorporating a specified low-molecular organic stilbene photoconductor. SOLUTION: This electrophotographic photoreceptor is provided with a photosensitive layer containing the stilbene compound represented by formula I in which X is an H atom or a group represented by formula II; each of Ar1 and Ar4 , and Ar2 in the case of X being an H atom is an alkyl or optionally substituted aralkyl group or the like; each of Ar3 and Ar5 and Ar6 , and Ar2 in the case of X being a group of formula II is an arylene or optionally substituted divalent bonding group or the like; each of R1 , R2 , R4 , R5 , R7 and R8 is an H atom or an optionally substituted alkyl group or the like; each of R3 and R6 is an aryl or heterocyclic group each optionally substituted or the like; each of (l) and (m) is an integer of >=1; and (n) is an integer of >=2.

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. More specifically, the present invention relates to an electrophotographic photoreceptor having a photosensitive layer containing a specific organic low-molecular-weight photoconductive compound. The electrophotographic photoreceptor of the present invention has very high sensitivity and high performance.

[0002]

2. Description of the Related Art Conventionally, inorganic photoconductive substances such as selenium, cadmium sulfide, and zinc oxide have been widely used for a photosensitive layer of an electrophotographic photosensitive member. However, selenium and cadmium sulfide need to be recovered as toxic, selenium is crystallized by heat and has poor heat resistance, cadmium sulfide and zinc oxide have poor moisture resistance, and zinc oxide has no printing durability. Therefore, efforts have been made to develop new photoconductors. Recently, studies have been made on the use of organic photoconductive materials for the photosensitive layer of an electrophotographic photoreceptor, and some of them have been put to practical use. Organic photoconductive materials are lighter, easier to form films, easier to produce photoconductors, can produce transparent photoconductors depending on the type, and are harmless as compared to inorganic ones. And so on. Recently, the so-called function-separated type photoreceptor, in which the functions of generating and transferring charge carriers are shared by different compounds, is effective for increasing the sensitivity, and has become the mainstream of development. Practical use of photoreceptors is also being carried out.

As a charge carrier transfer medium, there are a case where a polymer photoconductive compound such as polyvinyl carbazole is used and a case where a low molecular weight photoconductive compound is dispersed and dissolved in a binder polymer. In particular, when using an organic low-molecular-weight photoconductive compound, film properties as a binder,
Since a polymer having excellent flexibility and adhesiveness can be selected, a photoreceptor having excellent mechanical properties can be easily obtained, and various proposals have been made so far (Japanese Patent Application Laid-Open No. 58-1983). Nos. 198043, 61-69070, 63
-269160 publications).

[0004]

However, the organic low-molecular-weight photoconductive compounds proposed so far do not have sufficiently satisfactory performance for producing a high-sensitivity electrophotographic photoreceptor. An object of the present invention is to provide an organic low molecular weight photoconductive compound suitable for producing a highly sensitive electrophotographic photoreceptor.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result, have found that a specific stilbene compound is suitable as an organic low-molecular photoconductive compound. The invention has been completed.

That is, the present invention provides an electrophotographic photosensitive member having a photosensitive layer on a conductive substrate, wherein the photosensitive layer contains a stilbene compound represented by the following general formula (I). Electrophotographic photoreceptor.

[0007]

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(Wherein X is a hydrogen atom or a general formula (II)

[0009]

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Represents a group represented by the formula: Ar₁, Ar_FourAnd
Ar wherein X and X are hydrogen atoms_TwoHas a substituent
Alkyl group, aralkyl optionally having substituent (s)
Group, an aryl group which may have a substituent,
A heterocyclic group, a condensed polycyclic group which may have a substituent, or
Or a biphenyl group which may have a substituent,
May be the same or different from each other; Ar_Three, A
r_Five, Ar₆And X is a group represented by the formula (II)
r_TwoIs an arylene which may have a substituent
Group, divalent heterocyclic group which may have a substituent,
May have a divalent fused polycyclic group, or
Also represent good biphenylene groups, which are the same or different
R₁, R_Two, R_Four, R_Five, R₇and
R₈Are a hydrogen atom and an atom which may have a substituent, respectively.
Alkyl group, aralkyl group which may have a substituent, substituent
An aryl group which may have a heterocyclic group which may have a substituent
A ring group or a condensed polycyclic group which may have a substituent.
And they may be the same or different from each other;
_ThreeAnd R₆Are each an ant which may have a substituent.
Or a heterocyclic group which may have a substituent, or
Represents a condensed polycyclic group which may have a group,
May be the same or different; Ar₁And Ar_Two, Ar_Two
And Ar_Three, Ar₁And Ar_Three, Ar_FourAnd Ar_Five, Ar_FiveWhen
Ar₆, Ar_FourAnd Ar₆, R_TwoAnd R_Three, R_FiveAnd R₆And
And multiple R₇And R₈R₇Or R ₈Comrade
Is R₇And R₈May be directly or via a linking group.
Good; l and m each represent an integer of 1 or more;
May be the same or different from each other;
Or when m is an integer of 2 or more,₁, R_Two,
R_FourOr R_FiveMay be the same or different, and n is 2
Represents an integer greater than or equal to ₇And R₈Are the same
May be different). Hereinafter, the present invention will be described in detail.
explain.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The electrophotographic photoreceptor of the present invention contains a stilbene compound represented by the general formula (I) in a photosensitive layer. In the formula (I), Ar ₁ and Ar ₄
Is 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 heterocyclic group such as a furyl group or a pyridyl group; a condensed polycyclic group such as a pyrenyl group, an anthracenyl group, or a fluorenyl group; a biphenylene group, particularly preferably an aryl group, a condensed polycyclic group, or a biphenylene group; They may be the same or different. These alkyl group, aralkyl group, aryl group, heterocyclic group, condensed polycyclic group and biphenylene group may have a substituent, and the substituent includes a hydroxyl group; a chlorine atom;
Halogen atom such as bromine atom and iodine atom; alkyl group such as methyl group, ethyl group, propyl group, butyl group and hexyl group; alkoxy group such as methoxy group, ethoxy group and butoxy group; allyl group; allyloxy group; benzyl group Aralkyl groups such as naphthylmethyl group and phenethyl group; aryloxy groups such as phenoxy group and toloxy group; aralkyloxy groups such as benzyloxy group and phenethyloxy group;
Aryl groups such as phenyl and naphthyl; thienyl,
A heterocyclic group such as a furyl group; an arylvinyl group such as a styryl group or a naphthylvinyl group; a dialkylamino group such as a dimethylamino group or a diethylamino group; a diphenylamino group;
Diarylamino group such as dinaphthylamino group; diaralkylamino group such as dibenzylamino group and diphenethylamino group; diheterocyclic amino group such as dithienylamino group and difurylamino group; diallylamino group; Combined disubstituted amino groups; nitro groups; acetyl groups;
An acyl group such as a benzoyl group is exemplified.

Ar ₂ , Ar ₃ , Ar ₅ and Ar ₆ are
An arylene group such as a phenylene group and a naphthylene group; a divalent heterocyclic group such as a thienylene group, a furylene group and a pyridylene group; a divalent fused polycyclic group such as a pyrenylene group, an anthracenylene group and a fluorenylene group; In particular, an arylene group, a divalent condensed polycyclic group and a biphenylene group are preferable, and these may be the same or different. These arylene groups, divalent heterocyclic groups, divalent condensed polycyclic groups, and biphenylene groups may have a substituent, and the substituent may be a hydroxyl group; a chlorine atom, a bromine atom, an iodine atom, or the like. Halogen atom; alkyl group such as methyl group, ethyl group, propyl group, butyl group, hexyl group; alkoxy group such as methoxy group, ethoxy group, butoxy group; allyl group; allyloxy group; benzyl group, naphthylmethyl group, phenethyl group Aroxy groups such as phenoxy group and toloxy group; aralkyloxy groups such as benzyloxy group and phenethyloxy group;
Aryl groups such as phenyl and naphthyl; thienyl,
A heterocyclic group such as a furyl group; an arylvinyl group such as a styryl group or a naphthylvinyl group; a dialkylamino group such as a dimethylamino group or a diethylamino group; a diphenylamino group;
A diarylamino group such as a dinaphthylamino group, a diaralkylamino group such as a dibenzylamino group or a diphenethylamino group; a diheterocyclic amino group such as a dithienylamino group or a difurylamino group; a diallylamino group; Combined disubstituted amino groups; nitro groups; acetyl groups;
An acyl group such as a benzoyl group is exemplified.

R ₁ , R ₂ , R ₄ , R ₅ , R ₇ and R ₈
Each represents 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 aryl group such as a phenyl group and a naphthyl group; an aralkyl group such as a benzyl group, a naphthylmethyl group and a phenethyl group; Heterocyclic groups such as thienyl group, furyl group and pyridyl group; pyrenyl group;
Represents a condensed polycyclic group such as an anthracenyl group or a fluorenyl group, which may be the same or different;
These alkyl group, aryl group, aralkyl group, heterocyclic group and condensed polycyclic group may have a substituent, and the substituent may be a hydroxyl group; a halogen atom such as a chlorine atom, a bromine atom and an iodine atom; Alkyl groups such as methyl group, ethyl group, propyl group, butyl group and hexyl group; alkoxy groups such as methoxy group, ethoxy group and butoxy group; allyl group; allyloxy group; aralkyl groups such as benzyl group, naphthylmethyl group and phenethyl group; Aryloxy groups such as phenoxy group, toloxy group; aralkyloxy groups such as benzyloxy group and phenethyloxy group; aryl groups such as phenyl group and naphthyl group; heterocyclic groups such as thienyl group and furyl group; styryl group; Aryl vinyl groups such as naphthyl vinyl group; dialkylamino groups such as dimethylamino group and diethylamino group; diphenyl A diarylamino group such as a mino group or a dinaphthylamino group, a diaralkylamino group such as a dibenzylamino group or a diphenethylamino group; a diheterocyclic amino group such as a dithienylamino group or a difurylamino group; a diallylamino group; A disubstituted amino group in which an amino group is combined; a nitro group; an acyl group such as an acetyl group and a benzoyl group.

R ₃ and R ₆ are each a phenyl group,
An aryl group such as a naphthyl group; a heterocyclic group such as a thienyl group, a furyl group and a pyridyl group; and a condensed polycyclic group such as a pyrenyl group, an anthracenyl group and a fluorenyl group, which may be the same or different. These aryl group, heterocyclic group, and condensed polycyclic group 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; a methyl group and an ethyl group. ,
An alkyl group such as 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; aralkyl groups such as allyloxy group, benzyl group, naphthylmethyl group, and phenethyl group; phenoxy group,
Aryloxy groups such as toloxy groups; aralkyloxy groups such as benzyloxy groups and phenethyloxy groups; aryl groups such as phenyl groups and naphthyl groups; heterocyclic groups such as thienyl groups and furyl groups; styryl groups and naphthyl vinyl groups Arylvinyl group; dialkylamino group such as dimethylamino group, diethylamino group; diarylamino group such as diphenylamino group, dinaphthylamino group; diaralkylamino group such as dibenzylamino group, diphenethylamino group; dithienylamino group And a diheterocyclic amino group such as a difurylamino group; a diallylamino group; a disubstituted amino group obtained by combining the above amino groups; a nitro group; and an acyl group such as an acetyl group or a benzoyl group.

In the formula (I), Ar₁And Ar_Two, Ar₁And A
r_Three, Ar_FourAnd Ar₆And Ar_FourAnd Ar_FiveIs also directly
Indicates that they may be linked via a bonding group, for example,
Ar ₁And Ar_TwoWhen the following general formula (IV),
Structures represented by (V), (VI), (VII) or (VIII)
You can also take structure.

[0016]

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Further, in the formula (I), it is shown that Ar ₂ and Ar ₃ and Ar ₅ and Ar ₆ may be linked directly or via a bonding group. For example, when Ar ₂ and Ar ₃ are linked, And the following general formulas (IX), (X), (XI), (XII) and (XIII).

[0018]

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In the formula (I), R ₂ , R ₃ and R ₅
And R ₆ may be linked directly or via a bonding group. For example, when R ₂ and R ₃ are linked, the following general formulas (XIV), (XV), (XVI), (XVII) ), (XVIII),
The structure represented by (XIX), (XX), (XXI) and (XXII) can be adopted.

[0020]

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In the above formulas (IV) to (XXII),

[0022]

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Represents a benzene ring which may have one or more substituents, and the substituent includes a hydroxyl group; a chlorine atom;
Halogen atom such as bromine atom and iodine atom; alkyl group such as methyl group, ethyl group, propyl group, butyl group and hexyl group; alkoxy group such as methoxy group, ethoxy group and butoxy group; allyl group; allyloxy group; benzyl group Aralkyl groups such as naphthylmethyl group and phenethyl group; aryloxy groups such as phenoxy group and toloxy group; aralkyloxy groups such as benzyloxy group and phenethyloxy group;
Aryl groups such as phenyl and naphthyl; thienyl,
A heterocyclic group such as a furyl group; an arylvinyl group such as a styryl group or a naphthylvinyl group; a dialkylamino group such as a dimethylamino group or a diethylamino group; a diphenylamino group;
A diarylamino group such as a dinaphthylamino group, a diaralkylamino group such as a dibenzylamino group or a diphenethylamino group; a diheterocyclic amino group such as a dithienylamino group or a difurylamino group; a diallylamino group; Combined disubstituted amino groups; nitro groups; acetyl groups;
An acyl group such as a benzoyl group is exemplified.

In the formula (I), a plurality of R₇And R
₈R₇Or R₈Comrade or R ₇And R₈Is also directly
Indicates that they may be linked via a linking group.
Represents an optionally substituted cycloalkyl group or the like;
As a substituent, a hydroxyl group; a chlorine atom, a bromine atom, an iodine atom
Halogen atom such as a child; methyl group, ethyl group, propyl
An alkyl group such as a butyl group, a hexyl group or the like; methoxy
Groups, ethoxy groups, butoxy groups and other alkoxy groups; allyl
Group; allyloxy group; benzyl group, naphthylmethyl group,
Aralkyl groups such as phenethyl group; phenoxy group, trilo
Aryloxy groups such as xy groups; benzyloxy groups,
An aralkyloxy group such as a netyloxy group; a phenyl group;
Aryl groups such as naphthyl groups; thienyl groups, furyl groups, etc.
Heterocyclic group; aryl such as styryl group and naphthylvinyl group
Vinyl group; dimethylamino group, diethylamino group, etc.
Alkylamino group; diphenylamino group, dinaphthylua
Diarylamino group such as amino group, dibenzylamino group,
Diaralkylamino groups such as diphenethylamino group;
Diheterocyclic amino such as enylamino group and difurylamino group
Group; diallylamino group; a combination of the above amino groups
Disubstituted amino group; nitro group; acetyl group, benzoyl group
And the like. l and m are each 1
Represents an integer greater than or equal to 1, particularly preferably 1 or 2, and n is 2
It represents the above integer, and 2 or 3 is particularly preferable.

In the following, typical examples of the stilbene compound represented by the formula (I) are shown in Table 1. These typical examples are shown for illustrative purposes only. It is not limited to these representative examples.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

[Table 3]

[0029]

[Table 4]

[0030]

[Table 5]

[0031]

[Table 6]

[0032]

[Table 7]

[0033]

[Table 8]

[0034]

[Table 9]

[0035]

[Table 10]

[0036]

[Table 11]

[0037]

[Table 12]

[0038]

[Table 13]

The stilbene compound represented by the formula (I) can be produced by a known method. Preferred production methods are described below for the case where -X is a hydrogen atom and the case where -X is-(CR ₄ = CR ₅ ) _m -R _{6 represented by} the formula (II).

(1) When -X is -H For example, a known carbonyl-introducing reaction is carried out using a known arylamine compound as a raw material, and then a Wittig reaction is carried out to obtain a desired compound. Is the way. To explain this method in detail, first,

[0041]

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When R ₁ = H In the formula (XXIII) (in the formulas (XXIII) and (XXIV), X, n, A
r ₁ , Ar ₂ , Ar ₃ , Ar ₄ , Ar ₅ , Ar ₆ ,
R ₁ , R ₇ and R ₈ have the same meaning as in the general formula (I)) in the presence of phosphorus oxychloride in the presence of N, N-dimethylformamide, N-methylformanilide The aldehyde derivative represented by the general formula (XXIV) can be obtained by reacting with a formylating agent such as Although a large excess of the formylating agent can be used as a reaction solvent, an inert solvent such as o-dichlorobenzene and benzene can also be used.

In the case of R ₁ ≠ H, the arylamine compound represented by the formula (XXIII) is reacted with a Lewis acid such as aluminum chloride, iron chloride or zinc chloride in the presence of
Nitrobenzene, dichloromethane, four in a solvent such as carbon tetrachloride, by reaction with an acid chloride represented by the general formula Cl-CO-R _1, ketone body represented by formula (XXIV).

Then, the obtained aldehyde or ketone represented by the formula (XXIV) is reacted with N, N-dimethoxyformamide, N, N-dimethylacetamide, tetrahydrofuran, dioxane, benzene, toluene, etc., in a known manner. In an organic solvent of the formula (XXV) (wherein R ₁ ,
R ₂ , R ₃ and 1 have the same meanings as in formula (I), and Q represents a halogen atom such as a chlorine atom or a bromine atom) and triphenylphosphine. Or a Wittig reagent obtained by reacting the halogen compound with a trialkoxy phosphorus compound (R ₉ O) ₃ P (R ₉ represents an alkyl group such as a methyl group or an ethyl group) at 10 to 200 ° C. The compound represented by the formula (I) by reacting at a temperature of preferably from 20 to 100 ° C in the presence of a known basic catalyst such as butyllithium, phenyllithium, sodium methoxide, sodium ethoxide, potassium t-butoxide. Is obtained.

At this time, any of the cis-form, the trans-form, and a mixture of the cis-form and the trans-form is obtained. (In the following formula, the formula (I) represents any of a cis form, a trans form, and a mixture of the cis form and the trans form)

[0046]

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[0047]

(2) -X is-(CR ₄ = CR ₅ ) _m -R ₆
in the case of

For example, this is a method in which a known arylamine compound is used as a raw material, a known carbonyl introduction reaction is performed, and then a Wittig reaction is performed to obtain a desired compound. To explain this method in detail, first,

[0049]

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When R ₁ = R ₄ = H The arylamine compound represented by the formula (XXIII) is reacted with N, N-dimethylformamide in the presence of phosphorus oxychloride,
When reacted with a formylating agent such as N-methylformanilide, the compound has the formula (XXIV) (wherein Ar ₁ , Ar ₂ , Ar ₃ , Ar
₄ , R ₁ , R ₄ , R ₇ and R ₈ have the same meaning as in formula (I)). Although a large excess of the formylating agent can be used as a reaction solvent, an inert solvent such as o-dichlorobenzene and benzene can also be used.

When R ₁ ≠ H, R ₄ ≠ H: The arylamine compound represented by the formula (XXIII) is dissolved in a solvent such as nitrobenzene, dichloromethane or carbon tetrachloride in the presence of a Lewis acid such as aluminum chloride, iron chloride or zinc chloride. In the general formula Cl-CO-R ₁ or Cl-CO-R ₄
By reacting the compound with an acid chloride represented by the following formula, a ketone compound represented by the general formula (XXVI) is obtained. Also, R ₁
And R ₄ may be the same or different, R ₁
In the case of ≠ R ₄ , this can be achieved by mixing the acid chlorides to be added or adding them stepwise.

In the case where one of R ₁ and R ₄ is a hydrogen atom and the other is not a hydrogen atom, this can be achieved by performing the synthesis method in the above two cases stepwise.

Then, the obtained aldehyde or ketone represented by the formula (XXVI) is reacted with N, N-dimethylformamide, N, N-dimethylaldehyde, tetrahydrofuran, dioxane, benzene, toluene or the like in a known manner. In an organic solvent of

[0054]

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In the above formulas (XXV) and (XXVII) ((XXVI) and (XXVII), R ₁ , R ₂ , R ₃ , R ₄ , R ₅ ,
R ₆ , l and m have the same meanings as in formula (I), and Q represents a halogen atom such as a chlorine atom, a bromine atom or the like) and triphenylphosphine. Or a Wittig reagent obtained by reacting the halogen compound with a trialkoxy phosphorus compound (R ₁₀ O) ₃ P (R ₁₀ represents an alkyl group such as a methyl group or an ethyl group) at 10 to 200 ° C., preferably Is reacted at a temperature of 20 to 100 ° C. in the presence of a known basic catalyst such as butyllithium, phenyllithium, sodium methoxide, sodium ethoxide, potassium t-butoxide to give the compound represented by the formula (I). can get. At this time, an asymmetric stilbene compound represented by the formula (I) can be obtained by mixing the two types of Wittig reagents (XXV) and (XXVII) in some cases. 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. (In the following formula, Formula (I) represents any of a cis-form, a trans-form, and a mixture of a cis-form and a trans-form.) (XXV) and (XXVII) may be used alone or as a mixture.
In some cases, the reaction may be performed stepwise.

In these reactions, depending on the case, after completion of each step or after completion of all the steps, it is possible to obtain a highly purified product by a known purification means such as recrystallization purification, sublimation purification, column purification and the like. . The electrophotographic photoreceptor of the present invention has a photosensitive layer containing one or more styryl compounds represented by the formula (I). The stilbene compound represented by the formula (I) shows extremely excellent performance as an organic photoconductor. Particularly, when used as a charge transport medium, a photosensitive member having high sensitivity and excellent durability is provided.

Various forms of the photosensitive layer of the electrophotographic photosensitive member are known, and any of the photosensitive layers of the electrophotographic photosensitive member of the present invention may be used. For example, a photosensitive layer in which a stilbene compound and a dye or an electron-withdrawing compound serving as a sensitizer are added as needed in a binder, and a charge generating agent particle and a stilbene compound that generate charge carriers with extremely high efficiency when absorbing light are used. A photosensitive layer added in a binder, a charge transport layer composed of a stilbene compound and a binder, and a charge generation layer composed of charge generator particles that generate charge carriers with extremely high efficiency for absorbing light or a charge generation layer composed of this and a binder were laminated. And a photosensitive layer.

In these photosensitive layers, together with the stilbene compound represented by the formula (I), other known arylamine compounds, hydrazone compounds and stilbene compounds having excellent performance as organic photoconductors are included. You may mix. In the present invention, when the stilbene compound represented by the formula (I) is used in the charge transport layer of the photosensitive layer composed of the charge generation layer and the charge transport layer, the sensitivity is particularly high, the residual potential is small, and In addition, when used repeatedly, it is possible to obtain a photosensitive member which has little fluctuation in surface potential, lower sensitivity, accumulation of residual potential, and the like, and has excellent durability.

The electrophotographic photoreceptor of the present invention is prepared by dissolving a stilbene compound represented by the formula (I) together with a binder in a suitable solvent according to a conventional method and, if necessary, absorbing light. A coating solution obtained by adding a charge generating agent particle, a sensitizing dye, an electron-withdrawing compound, or a plasticizer, a pigment or other additives that generates It can be produced by forming a photosensitive layer having a thickness of from micron to several tens of micron, preferably from 10 to 40 micron. In the case of a photosensitive layer consisting of two layers, a charge generation layer and a charge transport layer, the above-mentioned coating layer is applied on the charge generation layer, or the charge generation layer is formed on the charge transport layer obtained by applying the above coating solution. Can be produced. More preferably, a structure in which a charge transport layer containing the stilbene compound of the formula (I) is provided on the charge generation layer is preferable. In this case, the charge generation layer is 0.1 to 5 μm, and the charge transport layer is 10 to 50 μm.
Preferably, it has a thickness of m.

Examples of the solvent for preparing the 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; Aprotic polar solvents such as acetonitrile, N-methylpyrrolidone, dimethylsulfoxide;
Esters such as ethyl acetate, methyl formate and methyl cellosolve acetate; and solvents dissolving stilbene compounds such as chlorinated hydrocarbons such as dichloroethane and chloroform. Of course, it is necessary to select a material that dissolves the binder from these. Further, as the binder, styrene, vinyl acetate, vinyl chloride, acrylic acid ester, methacrylic acid ester, polymers and copolymers of vinyl compounds such as butadiene, polyvinyl acetal, polycarbonate, polyester, polyphenylene oxide, polyurethane, cellulose ester, Various polymers compatible with styrene compounds, such as cellulose ether, phenoxy resin, silicon resin, and epoxy resin, may be mentioned. The amount of the binder used, whether laminated or single-layer, is usually in the range of 0.5 to 30 times, preferably 0.7 to 10 times the weight of the stilbene compound.

A charge generating particle added to the photosensitive layer,
Known dyes and electron-withdrawing compounds can be used. Selenium, a charge generator particle that generates charge carriers with extremely high efficiency when absorbing light,
Inorganic charge generator particles such as selenium-tellurium alloy, selenium-arsenic alloy, cadmium sulfide, amorphous silicon; metal-containing phthalocyanine, perylene pigment, thioindigo, quinacridone, perylene pigment, anthraquinone pigment, azo pigment, bisazo pigment And organic charge generating particles such as trisazo pigments, tetrakis azo pigments and cyanine pigments. Particularly when combined with a bisazo pigment, an excellent photoreceptor having improved sensitivity and low residual potential can be obtained.

Examples of the dyes include triphenylmethane dyes such as methyl violet, brilliant green and crystal violet, thiazine dyes such as methylene blue, quinone dyes such as quinizarin, cyanine dyes, pyrylium salts, thiapyrylium salts and benzopyrylium salts. Is mentioned. Examples of the electron withdrawing compound that forms a charge transfer complex with a stilbene compound include chloranil, 2,3-dichloro-1,4-naphthoquinone,
Quinones such as 1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone, 2-chloroanthraquinone and phenanthrenequinone; aldehydes such as 4-nitrobenzaldehyde; 9-benzoylanthracene, indandione, 3,5-dihydrobenzophenone, 2,
Ketones such as 4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, 3,3 ', 5,5'-tetranitrobenzophenone; phthalic anhydride,
Acid anhydrides such as -chloronaphthalic anhydride; tetracyanoethylene, terephthalmalononitrile, 9-anthrylmethylidenemalononitrile, 4-nitrobenzalmalononitrile, 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.

Further, the photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a well-known plasticizer in order to improve film formability, flexibility and mechanical strength. Therefore, examples of the plasticizer to be added to the coating solution include phthalic acid esters, phosphoric acid esters, epoxy compounds, chlorinated paraffins, chlorinated fatty acid esters, and aromatic compounds such as methylnaphthalene. When the stilbene compound is used as the charge transporting agent in the charge transporting layer, the coating solution may have the above-mentioned composition, but the charge generating particles, the dye, the electron withdrawing compound and the like may be removed or a small amount may be added. . In this case, as the charge generation layer, a coating solution obtained by dissolving or dispersing the charge generation particles and a solvent such as a binder polymer or an organic photoconductive substance, a dye, or an electron withdrawing compound as necessary was applied and dried. Examples thereof include a thin layer and a layer formed by depositing the charge generating agent by a method such as vapor deposition.

The photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a well-known additive in order to improve electric characteristics or durability in repeated use. For this purpose, the additives to be added to the coating solution include phenol compounds, organic phosphorus compounds, organic sulfur compounds and the like. It goes without saying that the photoreceptor thus formed may have an adhesive layer, an intermediate layer, a transparent insulating layer, and the like, if necessary.

As the conductive substrate on which the photosensitive layer is formed, any of those used for known electrophotographic photosensitive members can be used. Specifically, for example, a metal drum or sheet of aluminum, stainless steel, copper, or the like, a laminate of these metal foils, and a vapor-deposited material may be used. In addition, metal powder, carbon black, copper iodide, a conductive material such as a polymer electrolyte applied with an appropriate binder, and subjected to a conductive treatment plastic film, plastic drum, paper,
Paper tubes and the like. Further, a plastic sheet or drum containing a conductive substance such as a metal powder, carbon black, or carbon fiber to become conductive may be used.

[0066]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following production examples and examples unless it exceeds the gist. In the examples, “parts” means “parts by weight”.

[Production Example 1] 5.0 g of a bisaldehyde compound represented by the following formula:

[0068]

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11.1 g of a Wittig reagent represented by the following formula:
of

[0070]

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4.9 g of NaOMe (28% methanol solution) was added to a dimethylformamide (50 ml) solution, and the mixture was stirred at 70 ° C. for 1 hour. Thereafter, the reaction solution was poured into water and subjected to extraction, concentration, and purification treatments in a usual manner to obtain 4.5 g of a yellow glassy solid. This compound was found to be a stilbene-based compound (exemplified compound No. 17) having the following structural formula by mass spectrometry and infrared absorption spectrum measurement (FIG. 1). (Mass Spectrometry Results) As C ₅₅ H ₄₆ N ₂ . W = 734 M ⁺ = 734

[0072]

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[Production Example 2] In the same manner as in Production Example 1, 5.0 g of the bisaldehyde compound used in Production Example 1 and 11.2 g of the Wittig reagent represented by the following formula were used.

[0074]

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By reacting, 3.8 g of a yellow glassy solid was obtained. This compound was found to be a stilbene-based compound (exemplified compound No. 16) having the following structural formula by mass spectrometry and infrared absorption spectrum measurement (FIG. 2). (Mass Spectrometry Results) As C ₆₇ H ₅₄ N ₂ . W = 886 M ⁺ = 886

[0076]

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Example 1 1.0 part of a naphthalic acid-based bisazo pigment represented by the following structural formula was used.

[0078]

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In addition to 14 parts of dimethoxyethane and dispersion treatment with a sand glider, 14 parts of dimethoxyethane and 14 parts of 4-methoxy-4-methylpentanone-2 (manufactured by Mitsubishi Chemical Corporation) were added and diluted. Further, 0.5 part of polyvinyl butyral (trade name "Denka Butyral"# 6000-C, manufactured by Denki Kagaku Kogyo KK) and phenoxy resin (trade name "UCA" manufactured by Union Carbide Co., Ltd.)
R "(registered trademark) PKHH) (0.5 part) was mixed with a solution in which 6 parts of dimethoxyethane and 6 parts of 4-methoxy-4-methylpentanone-2 were dissolved to obtain a dispersion.
The weight of the dispersion after drying was 0.2 g on an aluminum deposition layer deposited on a polyester film having a thickness of 75 μm.
/ M ² , and dried to form a charge generation layer. On this, 90 parts of the stilbene compound produced in Production Example 1 and the polycarbonate resin shown below

[0080]

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A coating solution prepared by dissolving 100 parts in 900 parts of tetrahydrofuran was applied and dried to form a 20 μm-thick charge transport layer. The sensitivity, that is, half-exposure amount, of the electrophotographic photoreceptor having the two-layered photosensitive layer obtained as described above was 0.68 lux / sec. The half-exposure amount is obtained by first negatively charging the photoreceptor in a dark place with a corona current of 22 μA, then exposing the same to white light of 1 lux, and measuring the exposure amount required for the surface potential to attenuate from −450 V to −225 V. Determined by Further, when the surface potential when the exposure time was set to 9.9 seconds was measured as a residual potential, it was 8 V.

Example 2 Instead of the naphthalic acid-based bisazo pigment used in Example 1, the X-ray diffraction spectrum showed a Bragg angle (2θ ± 0.2 °) of 9.3 ° and 13.2.
Photoreceptor prepared in the same manner as in Example 1 except that an oxytitanium phthalocyanine pigment exhibiting main diffraction peaks at °, 26.2 °, and 27.1 °, a styryl compound, 70 parts, and a charge transport layer having a thickness of 17 μm were used. Was exposed to light of 780 nm (light amount: 500 nW), and the half-exposure amount was measured to be 0.69 μJ / cm ² .

Example 3 The half-life exposure of a photoreceptor prepared in the same manner as in Example 1 except that the stilbene compound synthesized in Production Example 2 was used instead of the stilbene compound used in Example 1 was measured. After that, 0.57lux
sec. The residual potential was 2V.

Example 4 The half-life exposure of a photoreceptor prepared in the same manner as in Example 2 except that the stilbene compound synthesized in Production Example 2 was used instead of the stilbene compound used in Example 2 was measured. As a result, 0.54 μJ / c
m ² .

[0085]

The photoreceptor for electrophotography of the present invention has a very high sensitivity and a small residual potential which causes fogging.
In particular, since there is little light fatigue, accumulation of residual potential due to repeated use or strong exposure, small fluctuations in surface potential and sensitivity, and excellent durability, it is not only suitable for PPC, but also stable and reliable in performance. It is a photoreceptor suitable for a photoreceptor for a printer, such as a laser printer, a liquid crystal shutter printer, and an LED printer, which require particularly high performance.

[Brief description of the drawings]

FIG. 1 is an infrared absorption spectrum of a stilbene compound produced in Production Example 1.

FIG. 2 is an infrared absorption spectrum of a stilbene compound produced in Production Example 2.

Claims (9)

[Claims] 1. An electrophotographic photosensitive member having a photosensitive layer on a conductive substrate, wherein the photosensitive layer contains a stilbene compound represented by the following general formula (I). Photoreceptor. Embedded image (Wherein X is a hydrogen atom or a general formula (II) Represents a group represented in, Ar ₂ Ar _1, Ar ₄ and X is a hydrogen atom, an alkyl group which may have a substituent, aralkyl group which may have a substituent, have a substituent An aryl group which may be substituted, a heterocyclic group which may have a substituent, a condensed polycyclic group which may have a substituent, or a biphenyl group which may have a substituent. Ar ₃ , Ar ₅ , Ar ₆ may be the same or different from each other;
And Ar ₂ in which X is a group represented by the formula (II) is an arylene group optionally having a substituent, a divalent heterocyclic group optionally having a substituent, A divalent fused polycyclic group or a biphenylene group which may have a substituent, which may be the same or different; R ₁ , R ₂ , R ₄ , R ₅ , R ₇ and R ₈ each have 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, also heterocyclic group, or represents an condensed polycyclic group which may have a substituent, they may be the same or different from each other; R ₃ and R
₆ represents 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. But may be different; Ar ₁ and Ar ₂ , Ar ₂ and Ar ₃ ,
Ar ₁ and Ar ₃ , Ar ₄ and Ar ₅ , Ar ₅ and Ar ₆ , A
r ₄ and Ar ₆ , R ₂ and R ₃ , R ₅ and R _6, and R ₇ or R _{8 of a} plurality of R ₇ and R ₈ , or R ₇ and R
₈ may be linked directly or via a linking group;
m represents an integer of 1 or more, which may be the same or different from each other; or, when 1 or m is an integer of 2 or more, a plurality of R ₁ , R ₂ , R _4, or R ₅ May be the same or different; n represents an integer of 2 or more, and a plurality of R ₇ and R ₈ may be the same or different) 2. The electrophotographic photoconductor according to claim 1, wherein n is 2 or 3 in the formula (I). 3. The electrophotographic photoconductor according to claim 1, wherein in the formula (I), 1 and m are each 1 or 2. 4. The electrophotographic photoconductor according to claim 1, wherein in formula (I), X—Ar ₂ is a phenyl group and Ar ₅ is a phenylene group. 5. A photosensitive layer containing a charge generating agent and a charge transporting agent, wherein a stilbene compound represented by the formula (I) is used as the charge transporting agent.
The electrophotographic photosensitive member according to any one of the above. 6. The photosensitive layer has a charge transport layer containing at least a charge transport agent, a charge generator layer containing a charge generator and a binder resin, and the charge transport agent in the charge transport layer has the formula (I)
The electrophotographic photoconductor according to any one of claims 1 to 4, wherein a stilbene compound represented by the following formula is used. 7. The electrophotographic photosensitive member according to claim 1, wherein the charge transport layer contains a charge transport agent and a binder resin. 8. A conductive support comprising a stilbene compound represented by the formula (I) as a charge transporting agent on a conductive support, wherein the charge generating agent contains a coupler component represented by the following general formula (III) in the molecule. 2. An azo pigment having
5. The electrophotographic photoconductor according to any one of items 1 to 4, Embedded image (Wherein, B represents a nitrogen-containing heterocyclic divalent group or an aromatic hydrocarbon divalent group, which may have a substituent) 9. A conductive support comprising a stilbene compound represented by the formula (I) as a charge transporting agent on a conductive support, and a Bragg angle (2θ ± 2) in an X-ray diffraction spectrum as a charge generating agent.
0.2 °) oxytitanium phthalocyanine or (2θ ± 0.2 °) showing a main diffraction peak at 27.3 °
2. A photosensitive layer containing oxytitanium phthalocyanine having main diffraction peaks at 9.3 °, 13.2 °, 26.2 ° and 27.1 °.
5. The electrophotographic photoconductor according to any one of items 1 to 4,