JP2005263725A - Stilbene derivative, method for producing the same, and electrophotographic photoreceptor using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new stilbene derivative, to provide a method for producing the same, and to provide an electrophotographic photoreceptor improved in sensitivity than ever. <P>SOLUTION: The stilbene derivative is represented by the general formula(1)[wherein, R<SB>1</SB>and R<SB>2</SB>are each (un)substituted 1-8C alkyl or (un)substituted 1-20C aryl; R<SB>3</SB>to R<SB>14</SB>are each H, (un)substituted 1-8C alkyl, (un)substituted 1-8C alkoxy or (un)substituted 1-20C aryl; and m is an integer of 2-5]. The stilbene derivative is obtained by formylating the para-site on the phenyl group of a triphenylamine followed by reacting a diphosphoric ester derivative. The electrophotographic photoreceptor is such that a photosensitive layer containing this stilbene derivative is provided on an electrically conductive substrate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a stilbene derivative having excellent charge transporting ability, a method for producing the stilbene derivative, and an electrophotographic photosensitive member containing the stilbene derivative and used in an image forming apparatus such as an electrostatic copying machine, a facsimile machine, or a laser beam printer.

In the image forming apparatus, various organic photoreceptors having sensitivity in the wavelength region of the light source used in the apparatus are used.
This organic photoconductor is easier to manufacture than conventional inorganic photoconductors, and there are various options for photoconductor materials such as a charge transport agent, a charge generator, and a binder resin, and the degree of freedom in functional design is high. In recent years, it has been widely used because of its advantages.

The organic photoreceptor includes a single layer type photoreceptor in which a charge transport agent is dispersed in the same photosensitive layer together with a charge generator, a charge generation layer containing a charge generator, and a charge transport layer containing a charge transport agent. There is a laminated type photoreceptor in which is laminated.
A stilbene derivative represented by the following general formula (6) is known as a charge transport agent used in the organic photoreceptor. (For example, refer to Patent Document 1).
General formula (6):

Wherein R ¹ , R ² , R ⁵ and R ⁶ are the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group or an aryl group, and R ³ and R ⁴ are the same or different and represent an alkyl group, an alkoxy group or An aryl group, m represents an integer of 1 to 10, and l, n, o, p, q and r are the same or different and represent an integer of 1 to 2)
JP 05-105646 A (Claims)

However, among the stilbene derivatives represented by the general formula (6), the compound specifically disclosed in the above publication has poor compatibility with the binder resin and is difficult to be uniformly dispersed in the photosensitive layer. There is a problem that movement is difficult to occur.
Therefore, even though the stilbene derivative (6) itself has a high charge mobility, when it is used as a charge transport agent for a photoreceptor, its characteristics cannot be fully exhibited, the residual potential is high, and the photosensitivity is high. Only an insufficient photoreceptor can be obtained.
Accordingly, an object of the present invention is to solve the above technical problems and to provide a novel stilbene derivative that can be suitably used as a charge transport agent for an electrophotographic photosensitive member and a method for producing the same.
Another object of the present invention is to provide an electrophotographic photoreceptor having improved sensitivity as compared with the prior art.

In order to solve the above-mentioned problems, the present inventors have repeatedly studied the molecular structure of the stilbene derivative represented by the general formula (6). As a result, the 2-position of one phenyl group in the diphenylamino group at the molecular end is as follows. When it has a substituent such as an alkyl group at the (ortho position), it is more compatible with the binder resin than the conventional stilbene derivative (6), has a large charge mobility, and a charge generator. The present inventors have found a completely new fact that it is excellent in the charge injecting property from the present invention and completed the present invention.
That is, the stilbene derivative of the present invention has the general formula (1):

(Wherein R ₁ and R ₂ are the same or different and each represents an optionally substituted alkyl group having 1 to 8 carbon atoms or an optionally substituted aryl group having 1 to 20 carbon atoms. R _{3 to} R ₁₄ are the same or different and are a hydrogen atom, an alkyl group having 1 to 8 carbon atoms which may have a substituent, or an alkoxy group having 1 to 8 carbon atoms which may have a substituent. Or an aryl group having 1 to 20 carbon atoms which may have a substituent, m represents an integer of 2 to 5.), and is a stilbene derivative.

In constituting the stilbene derivative of the present invention, it is preferable that R ₁ and R ₂ in the general formula (1) are alkyl groups having 1 to 8 carbon atoms.

  The method for producing the stilbene derivative (1) of the present invention has the general formula (2a):

And general formula (2b):

(Wherein R ₁ and R ₂ are the same or different and each represents an optionally substituted alkyl group having 1 to 8 carbon atoms or an optionally substituted aryl group having 1 to 20 carbon atoms. R _{3 to} R ₁₄ are the same or different and are a hydrogen atom, an alkyl group having 1 to 8 carbon atoms which may have a substituent, or an alkoxy group having 1 to 8 carbon atoms which may have a substituent. Or an aryl group having 1 to 20 carbon atoms which may have a substituent.) A formylated triphenylamine derivative represented by general formula (3):

(N represents an integer of 0 to 3)
It is characterized by reacting a diphosphate derivative represented by the formula:

  The formylated triphenylamine derivative (2a) used in the production method of the present invention has the general formula (4a):

(In the formula, R ₁ represents an alkyl group having 1 to 8 carbon atoms which may have a substituent or an aryl group having 1 to 20 carbon atoms which may have a substituent, and R ₃ and R ₄ represent The same or different, having a hydrogen atom, an optionally substituted alkyl group having 1 to 8 carbon atoms, an optionally substituted alkoxy group having 1 to 8 carbon atoms, or a substituent; An aryl group having 1 to 20 carbon atoms may be reacted with at least one iodobenzene derivative to produce a general formula (5a):

(In the formula, R ₁ represents an optionally substituted alkyl group having 1 to 8 carbon atoms or an optionally substituted aryl group having 1 to 20 carbon atoms, R _{3 to} R _7; R ₁₃ is the same or different and represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms which may have a substituent, an alkoxy group having 1 to 8 carbon atoms which may have a substituent, or a substituent. An aryl group having 1 to 20 carbon atoms which may be present.) And then formylating the compound (5a) by the Vilsmeier method. .

  The formylated triphenylamine derivative (2b) used in the production method of the present invention has the general formula (4b):

(Wherein R ₂ represents an alkyl group having 1 to 8 carbon atoms which may have a substituent or an aryl group having 1 to 20 carbon atoms which may have a substituent, and R ₈ and R ₉ are The same or different, having a hydrogen atom, an optionally substituted alkyl group having 1 to 8 carbon atoms, an optionally substituted alkoxy group having 1 to 8 carbon atoms, or a substituent; An aryl group having 1 to 20 carbon atoms may be reacted with at least one iodobenzene derivative to give a general formula (5b):

(In the formula, R ₂ represents an alkyl group having 1 to 8 carbon atoms which may have a substituent or an aryl group having 1 to 20 carbon atoms which may have a substituent, and R _{8 to} R _12, R ₁₄ may be the same or different and each represents a hydrogen atom, an optionally substituted alkyl group having 1 to 8 carbon atoms, an optionally substituted alkoxy group having 1 to 8 carbon atoms, or a substituent. An aryl group having 1 to 20 carbon atoms which may be present.) And then formylating this compound (5b) by the Vilsmeier method. .
The electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member in which a photosensitive layer is provided on a conductive substrate, and the photosensitive layer contains a stilbene derivative represented by the general formula (1). It is characterized by.

  The photosensitive layer is preferably a single-layer type photosensitive layer containing a stilbene derivative represented by the general formula (1) and a charge generating agent and an electron transporting agent.

According to the present invention, the stilbene derivative of the present invention represented by the general formula (1) is a compound not specifically disclosed in JP-A No. 05-105646, and is specifically disclosed in the above-mentioned publication. Compared with the prepared compound, the compatibility with the binder resin is high and the charge mobility is high.
Therefore, by using the stilbene derivative (1) of the present invention as a charge (hole) transport agent in an electrophotographic photosensitive member, an electrophotographic photosensitive member having higher sensitivity than the conventional one can be provided.

Further, according to the present invention, R ₁ and R ₂ in the general formula (1) are further excellent in compatibility with the binder resin by being an alkyl group having 1 to 8 carbon atoms. A stilbene derivative having high mobility and excellent charge injectability from the charge generating agent can be provided. In addition, such a substituent is relatively easy to introduce, and a predetermined stilbene derivative can be produced in a relatively high yield. In addition, according to the present invention, the formyl body is obtained by formylating triphenylamine derivatives (5a) and (5b) having a substituent at the 2-position (ortho-position) of a phenyl group by the Vilsmeier method. (2a) and (2b) can be produced efficiently, and as a result, the productivity of the stilbene derivative (1) can be improved.

When the triphenylamine derivatives (5a) and (5b) are formylated by the Vilsmeier method, only the formyl form (2a) or (2b) of triphenylamine which is a raw material of the stilbene derivative (1) is high. Produced in yield.
The reason is not clear, but among the three phenyl groups of the compounds (5a) and (5b), a phenyl group having a substituent R ₁ or R ₂ in the ortho position is a nitrogen atom as compared with other phenyl groups. Since the bond axis with the phenyl group is twisted by the influence of the substituent R ₁ , the electron donation from the nitrogen atom is poor and the nucleophilicity of the phenyl group is lowered, so that the phenyl having the substituents R ₁ and R ₂ It is presumed that the para position of the group is not formylated, and as a result, the para position of the other phenyl group is formylated.

  Further, according to the electrophotographic photoreceptor of the present invention, since the stilbene derivative represented by the general formula (1) is contained in the photosensitive layer, the compatibility with the binder resin is excellent, and the crystallization is effectively performed. Thus, it is possible to obtain an electrophotographic photosensitive member having a high speed of transporting charges (holes) generated by the charge generating agent (that is, having a high charge mobility) and excellent photosensitivity during charging and exposure.

Hereinafter, the present invention will be described in detail.

<Stilbene derivative>
In the stilbene derivative represented by the general formula (1), examples of the alkyl group corresponding to R _{1 to} R ₁₄ include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, and the like. Examples include butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl and the like. Among these, a group having 1 to 8 carbon atoms is preferable.

The alkyl group may have a substituent.
Examples of the alkyl group having a substituent include a hydroxyalkyl group, an alkoxyalkyl group, an aminoalkyl group, a monoalkylaminoalkyl group, a dialkylaminoalkyl group, a halogen-substituted alkyl group, an alkoxycarbonylalkyl group, a carboxyalkyl group, and an alkanoyloxyalkyl. Groups and the like.

In particular, in the stilbene derivative (1) of the present invention, the alkyl group has an electron donating group such as an alkoxy group, an amino group, a monoalkylamino group, and a dialkylamino group from the viewpoint of increasing charge mobility. preferable.
Examples of the hydroxyalkyl group include hydroxymethyl, 2-hydroxyethyl, 1,1-dimethyl-2-hydroxyethyl, 3-hydroxypropyl, 4-hydroxybutyl, 2-hydroxybutyl, 1-hydroxypentyl, and 6-hydroxy. Examples thereof include hydroxyalkyl groups having 1 to 6 carbon atoms in the alkyl moiety, such as hexyl.

Examples of the alkoxyalkyl group include, for example, methoxymethyl, methoxyethyl, methoxybutyl, ethoxymethyl, ethoxyhexyl, butoxyethyl, t-butoxyhexyl, hexyloxymethyl, etc. The alkoxyalkyl group which is 1-6 is mentioned.
Examples of the aminoalkyl group include aminoalkyl groups having 1 to 6 carbon atoms in the alkyl moiety, such as aminomethyl, aminoethyl, aminopropyl, aminobutyl, and aminohexyl.

  Examples of the monoalkylaminoalkyl group include methylaminomethyl, ethylaminomethyl, hexylaminomethyl, ethylaminoethyl, hexylaminoethyl, methylaminopropyl, butylaminopropyl, methylaminobutyl, ethylaminobutyl, hexylaminobutyl, Examples thereof include alkylaminoalkyl groups having 1 to 6 carbon atoms in the alkyl moiety, such as methylaminohexyl, ethylaminohexyl, butylaminohexyl, hexylaminohexyl and the like.

  Examples of the dialkylaminoalkyl group include dimethylaminomethyl, diethylaminoethyl, dihexylaminomethyl, diethylaminoethyl, dihexylaminoethyl, dimethylaminopropyl, dibutylaminopropyl, dimethylaminobutyl, diethylaminobutyl, dihexylaminobutyl, dimethylaminohexyl, Examples thereof include dialkylaminoalkyl groups having 1 to 6 carbon atoms in the alkyl moiety, such as diethylaminohexyl, dibutylaminohexyl, dihexylaminohexyl and the like.

  Examples of the halogen-substituted alkyl group include monochloromethyl, monobromomethyl, monoiodomethyl, monofluoromethyl, dichloromethyl, dibromomethyl, diiodomethyl, difluoromethyl, trichloromethyl, tribromomethyl, triiodomethyl, trifluoromethyl, 1 to 3 halogen atoms are substituted, such as monochloroethyl, monobromoethyl, monoiodoethyl, monofluoroethyl, dibromobutyl, diiodobutyl, difluorobutyl, chlorohexyl, bromohexyl, iodohexyl, fluorohexyl, etc. And an alkyl group having 1 to 6 carbon atoms.

  Examples of the alkoxycarbonylalkyl group include methoxycarbonylmethyl, methoxycarbonylethyl, methoxycarbonylhexyl, ethoxycarbonylmethyl, ethoxycarbonylethyl, propoxycarbonylmethyl, isopropoxycarbonylmethyl, butoxycarbonylmethyl, pentyloxycarbonylmethyl, hexylcarbonyl. Examples of the alkyl moiety and the alkoxy moiety such as methyl, hexylcarbonylbutyl, and hexylcarbonylhexyl include an alkoxycarbonylalkyl group having 1 to 6 carbon atoms.

Examples of the carboxyalkyl group include carboxyalkyl groups having 1 to 6 carbon atoms in the alkyl moiety, such as carboxymethyl, carboxyethyl, carboxybutyl, carboxyhexyl, 1-methyl-2-carboxyethyl, and the like.
Examples of the alkanoyloxyalkyl group include C2-C6 alkanoyl moieties such as acetoxymethyl, 2-acetoxyethyl, propionyloxymethyl, 1-hexanoyloxy-2-methylpentyl, and the like, and C1-C6 An alkanoyloxy group having an alkyl moiety.

Examples of the aryl group corresponding to R _{1 to} R ₁₄ include groups such as phenyl, naphthyl, anthryl, and phenanthryl.

The aryl group may have a substituent. Examples of the substituent include a halogen atom, an amino group, a hydroxyl group, an optionally esterified carboxyl group, a cyano group, and the like. The C1-C6 alkyl group which may have a substituent, the C1-C6 alkoxy group which may have a substituent, etc. are mentioned.
In addition, the substitution position of these substituents is not particularly limited.

Examples of the alkoxy group corresponding to R _{1 to} R ₁₄ include groups such as methoxy, ethoxy, n-propoxy, isopropoxy, tert-butoxy, n-pentyloxy, and n-hexyloxy.
Especially, it is preferable that it is a C1-C6 group of an alkyl part.
The alkoxy group may have a substituent. Examples of the substituent include substituents similar to the above-described alkyl groups such as a halogen atom, an amino group, a hydroxyl group, a carboxyl group, and an alkanoyloxy group. Is mentioned.

  Among the compounds represented by the above general formula (1), the stilbene derivative of the present invention is represented by the general formula (1 ′):

(Wherein R _{1 to} R ₁₄ are the same as described above), the groups R ₁ , R ₃ , R ₂ and R ₉ are all substituted in the ortho position. From the viewpoint of ease of compatibility or compatibility with the binder resin.
Further, m is preferably 2 or 3 from the viewpoint of ease of synthesis or compatibility with the binder resin.

Specific examples (1-1) to (1-9) and (2-1) to (2-9) of the stilbene derivative (1) of the present invention are shown in Table 1 below as substituents corresponding to R1 to R14. Show.
In Table 1, H is a hydrogen atom, Me is a methyl group, Et is an ethyl group, i-Pr is an isopropyl group, s-Bu is a sec-butyl group, t-Bu is a tert-butyl group, Ph is a phenyl group, n -Octyl represents an n-octyl group, and MeO represents a methoxy group.
The numbers shown in the columns of R ₂ , R ₄ and R ₆ indicate the substitution positions of the groups.
Thus, for example, “6-Me” indicates that the methyl group is substituted at the 6-position (ortho-position) of the phenyl group in the triphenylamine moiety, and “4-Et” is the 4-position (para-position) of the phenyl group. Indicates that the ethyl group is substituted.

In addition, the stilbene derivative (1) of the present invention includes a so-called cis isomer due to the difference in arrangement between the central benzene ring on both sides of the vinylene group (—CH═CH—) and the triphenylamine moiety. There are two isomers, the trans form.
In the present invention, the cis isomer and trans isomer of the stilbene derivative (1) are not particularly limited, but it is usually preferable to use the trans isomer.

<< Method for Producing Stilbene Derivative >> A method for synthesizing the stilbene derivative (1) of the present invention will be described.
Reaction formula (1):

(Wherein R _{1 to} R ₁₄ are the same as described above.)
As shown in the above reaction formula (1), the stilbene derivative of the present invention represented by the general formula (1) has a formyl form of triphenylamine represented by the general formulas (2a) and (2b) and the general formula (1). It is synthesized by reacting the diphosphate derivative represented by 3) in a suitable anhydrous solvent in the presence of a base.

The solvent used in the above synthesis reaction may be any solvent that does not affect the reaction. For example, ethers such as diethyl ether, tetrahydrofuran and dioxane; halogenated hydrocarbons such as methylene chloride, chloroform and dichloroethane; benzene and toluene And aromatic hydrocarbons.
Examples of the base include sodium alkoxide such as sodium methoxide, and metal hydride such as sodium hydride.
The total amount of diphosphate derivative and formylated triphenylamine derivative used is preferably such that the addition ratio is in the range of 1: 2.0 to 1: 2.4 in terms of molar ratio. The reaction is usually performed at −10 to 30 ° C. and is completed in about 1 to 12 hours.
If the left and right triphenylamine structures are different across the vinylene group (—CH═CH—) of the stilbene derivative (1), a protective group is appropriately added to the phosphate part of the disphosphate derivative (3). A reaction may be performed.

The formyl isomers (2a) and (2b) of triphenylamine are synthesized as shown in the following reaction formulas (2a) and (2b).
Reaction formula (2a):

Reaction formula (2b):

(In the formula, R _{1 to} R ₁₄ are the same as above.)
In this reaction, the aniline derivative (4a) or (4b) and iodobenzene (90) are added to nitrobenzene and reacted with a catalyst such as anhydrous potassium carbonate, copper, copper iodide, etc. to obtain the triphenylamine derivative (5a). Or (5b) is obtained, and then this triphenylamine derivative is formylated by the Filsmeier method to obtain a formyl form (2a) or (2b) of triphenylamine which is a starting material of the above reaction formula (I) Is.
In preparing the triphenylamine derivative represented by the general formula (5a) or (5b), one hydrogen of the amino group constituting the aniline derivative represented by the general formula (4a) or (4b) is substituted with an acetyl group. It is preferable to substitute with. That is, after protecting a part of the aniline derivative with an acetyl group, it is reacted with one kind of iodobenzene derivative. Next, it is preferable to remove the acetyl group of the obtained acetylated diphenylamine derivative and simultaneously add hydrogen, and further react with another type of iodobenzene derivative.

The use ratio of the aniline derivative and the total amount of iodobenzene in the reaction formulas (2a) and (2b) is 1: 2 to 1: 6 in molar ratio.
The reaction is usually carried out at 160 to 220 ° C. and is completed in about 4 to 30 hours.
Reagents used in the Vilsmeier method (Vilsmeier reagent) include (i) halogenating agents such as phosphorus oxychloride, phosgene, oxalyl chloride, thionyl chloride, triphenylphosphine-bromine, hexachlorotriphosphazatriene, and (ii) Prepared in combination with N, N-dimethylformamide (DMF), N-methylformanilide (MFA), N-formylmorpholine, N, N-diisopropylformamide and the like.
In particular, in the present invention, a combination of phosphorus oxychloride and DMF that can also be used as a solvent is preferably used.

In the preparation of the Vilsmeier reagent, the ratio of (i) and (ii) used is usually 1: 1 to 1:20, preferably 1: 1 to 1: 5 in terms of molar ratio.
The amount of the Vilsmeier reagent used is 0.9 to 2 times, preferably 1 to 1.1 times the amount of the triphenylamine derivative (5).
The formylation of the compound (5) is usually performed at 130 ° C. or less and is completed in about 2 to 5 hours.
The diphosphate ester derivative (3) is synthesized as shown in the following reaction formula (III).
Reaction formula (3):

(N represents an integer of 0 to 4)
In this reaction, a phosphoethylene derivative (91) is reacted with a phosphorous acid triester in the absence of a solvent or in a suitable solvent to obtain a diphosphate ester derivative (3) which is a starting material of the above reaction formula (I). Is.
At this time, when a tertiary amine is added, the alkyl halide is removed from the reaction system, and the reaction is accelerated.

The solvent used in the above reaction is not particularly limited as long as it does not affect the reaction. For example, ethers such as diethyl ether, tetrahydrofuran and dioxane; halogenated hydrocarbons such as methylene chloride, chloroform and dichloroethane; benzene and toluene Aromatic hydrocarbons, dimethylformamide and the like.
Examples of the tertiary amine include triethylamine, tributylamine, pyridine, 4- (dimethylamino) pyridine and the like.

The amount of phosphorous acid triester to be used for the dichloroethylene derivative (91) is at least a 2-fold molar amount, preferably a 2.1-5 molar amount.
The reaction is usually carried out at 80 to 150 ° C. and is completed in about 2 to 10 hours.
The stilbene derivative represented by the general formula (1) has a large charge mobility as described above, that is, it has a high hole transport ability, and therefore is suitably used as a hole transport agent in an electrophotographic photoreceptor. In addition, it can be used in various fields such as solar cells and electroluminescence elements.

<< Electrophotographic Photosensitive Member >> The electrophotographic photosensitive member of the present invention is obtained by providing a photosensitive layer containing a stilbene derivative represented by the general formula (1) on a conductive substrate.
As described above, there are a single layer type and a multilayer type photoreceptor, and the present invention can be applied to both of them.
A single-layer type photoreceptor is obtained by providing a single photosensitive layer on a conductive substrate.
This photosensitive layer is obtained by dissolving or dispersing a stilbene derivative (hole transport agent) represented by the general formula (1), a charge generator, a binder resin, and, if necessary, an electron transport agent in an appropriate solvent. The resulting coating solution is formed on a conductive substrate and dried.
Such a single-layer type photoreceptor can be applied to either a positive or negative charge type with a single configuration, and has a simple layer configuration and excellent productivity.

  The single layer type electrophotographic photosensitive member of the present invention is a single layer type electrophotographic photosensitive member obtained by using a stilbene derivative specifically disclosed in the above-mentioned JP-A No. 05-105646 as a hole transporting agent. In comparison, the residual potential of the photoreceptor is greatly reduced, and the sensitivity is improved.

  In addition, when the electron transport agent is further contained in the photosensitive layer of the single-layer electrophotographic photosensitive member of the present invention, electrons are efficiently exchanged between the charge generating agent and the hole transport agent, The sensitivity of the photoreceptor is further improved.

On the other hand, in the multilayer photoreceptor, first, a charge generation layer containing a charge generation agent is formed on a conductive substrate by means of vapor deposition or coating, and then, on this charge generation layer, the general formula (1) It is produced by applying a coating liquid containing at least one stilbene derivative (hole transport agent) and a binder resin, and drying to form a charge transport layer.
In contrast to the above, a charge transport layer may be formed on a conductive substrate, and a charge generation layer may be formed thereon.
However, since the charge generation layer is much thinner than the charge transport layer, it is preferable to form the charge generation layer on the conductive substrate and to form the charge transport layer thereon for protection. .

Depending on the order of formation of the charge generation layer and the charge transport layer and the type of charge transport agent used in the charge transport layer, the laminate type photoreceptor is selected as a positive or negative charge type.
For example, as described above, when a charge generation layer is formed on a conductive substrate and a charge transport layer is formed thereon, the charge transport agent in the charge transport layer can be used as the stilbene derivative (1) of the present invention. When a positive hole transport agent is used, the photoconductor is negatively charged.
In this case, the charge generation layer may contain an electron transport agent.

The laminated electrophotographic photosensitive member of the present invention is compared with the laminated electrophotographic photosensitive member obtained by using a stilbene derivative specifically disclosed in the above-mentioned JP-A No. 05-105646 as a hole transporting agent. The residual potential of the photoconductor is greatly reduced, and the sensitivity is improved.
As described above, the electrophotographic photosensitive member of the present invention can be applied to both a single layer type and a laminated type, but can be used for both positive and negative charging types, has a simple structure and is easy to manufacture, The single layer type is preferable from the viewpoints of being able to suppress film defects when forming a layer, reducing the interface between layers, and improving optical characteristics.
Next, various materials used for the electrophotographic photoreceptor of the present invention will be described.
(1) Examples of the charge generator used in the present invention include metal-free phthalocyanine, oxotitanyl phthalocyanine, perylene pigment, bisazo pigment, dithioketopyrrolopyrrole pigment, metal-free naphthalocyanine pigment, metal naphthalocyanine pigment, and squaraine pigment. , Trisazo pigments, indigo pigments, azurenium pigments, cyanine pigments, and the like, or a combination of two or more.

  In particular, an image forming apparatus of a digital optical system such as a laser beam printer or a facsimile using a light source such as a semiconductor laser needs a photosensitive member having a sensitivity in a wavelength region of 700 nm or more. For example, metal-free phthalocyanine, A phthalocyanine pigment such as oxotitanyl phthalocyanine is preferably used.

On the other hand, an analog optical image forming apparatus such as an electrostatic copying machine using a white light source such as a halogen lamp requires a photosensitive member having sensitivity in the visible region. For example, a perylene pigment or a bisazo pigment is used. Etc. are preferably used.
(2) Hole transport agent In the electrophotographic photoreceptor of the present invention, it is also preferable that the photosensitive layer contains another conventionally known hole transport agent together with the stilbene derivative of the present invention which is a hole transport agent.

  Examples of such hole transporting agents include various compounds having high hole transporting ability, such as compounds represented by the following general formulas (HT-1 to HT-13).

(Wherein R ^h1 , R ^h2 , R ^h3 , R ^h4 , R ^h5 and R ^h6 are independent of each other, and are a halogen atom, a substituted or unsubstituted alkyl group or alkoxy group having 1 to 20 carbon atoms, substituted or An unsubstituted aryl group having 6 to 40 carbon atoms, a and b are the same or different integers of 0 to 4, and c, d, e and f are the same or different 0 Represents an integer of ˜5, provided that when a, b, c, d, e or f is 2 or more, each R ^h1 , R ^h2 , R ^h3 , R ^h4 , R ^h5 and R ^h6 may be different. .)

(Wherein R ^h7 , R ^h8 , R ^h9 , R ^h10 and R ^h11 are independent of each other, and are a halogen atom, a substituted or unsubstituted alkyl group or alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted group, An aryl group having 6 to 40 carbon atoms, wherein g, h, i and j represent the same or different integers of 0 to 5 and k represents an integer of 0 to 4, provided that g, h , I, j or k is 2 or more, each R ^h7 , R ^h8 , R ^h9 , R ^h10 and R ^h11 may be different.)

^{(Wherein, R h12, R h13, R} h14 and R ^h15 are independent of each other, substituted or unsubstituted alkyl or alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted C 6 to 40 carbon ^{Represents an} aryl group, and R ^h16 represents a halogen atom, a cyano group, a nitro group, a substituted or unsubstituted alkyl group or alkoxy group having 1 to 20 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 40 carbon atoms. M, n, o and p represent the same or different integers of 0 to 5, and q represents an integer of 0 to 6, provided that m, n, o, p or q is 2 or more. when each ^{R h12, R h13, R h14} , R h15 and R ^h16 may be different.)

( ^Wherein R ^h17 , R ^h18 , R ^h19 and R ^h20 are independent of each other, and are a halogen atom, a substituted or unsubstituted alkyl group or alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon number of 6; Represents an aryl group of ˜40, r, s, t, and u represent the same or different integers of 0 to 5, provided that when r, s, t, or u is 2 or more, each R ^h17, R ^h18, R ^h19 and R ^h20 may be different.)

(In the formula, R ^h21 and R ^h22 are independent of each other and represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms or an alkoxy group. R ^h23 , R ^h24 , R ^h25 and R ^h26 are independent of each other. And represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 40 carbon atoms.)

(In the formula, R ^h27 , R ^h28 and R ^h29 are independent of each other and represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms or an alkoxy group.)

(In the formula, R ^h30 , R ^h31 , R ^h32 and R ^h33 are independent of each other and represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms or an alkoxy group.)

(In the formula, R ^h34 , R ^h35 , R ^h36 , R ^h37 and R ^h38 are independent of each other and represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms or an alkoxy group.)

(In the formula, R ^h39 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, R ^h40 , R ^h41 and R ^h42 are independent of each other; a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms; Or an alkoxy group.)

(Wherein, R ^h43, R ^h44 and R ^h45 are independent of each other, represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group having 1 to 20 carbon atoms.)

(In the formula, R ^h46 and R ^h47 are independent of each other, and are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group or alkoxy group having 1 to 20 carbon atoms, or a substituted or unsubstituted carbon atom having 6 to 6 carbon atoms. 40 aryl groups are shown.)

(In the formula, R ^h50 , R ^h51 , R ^h52 , R ^h53 , R ^h54 and R ^h55 are independent of each other, and are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or an alkoxy group. Or a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, α represents an integer of 1 to 10, and v, w, x, y, z and β may be the same or different. Represents an integer of 0 to 2, provided that when v, w, x, y, z or β is 2, each R ^h50 , R ^h51 , R ^h52 , R ^h53 , R ^h54 and R ^h55 may be different. .)

(In the formula, R ^h56 , R ^h57 , R ^h58 and R ^h59 are independent of each other, and represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group or alkoxy group having 1 to 20 carbon atoms, and Φ is It is a group represented by any of the formulas.)

Further, in the present invention, together with the above exemplified hole transport agents HT-1 to HT-13 and the like, a conventionally known hole transport material, 2,5-di (4-methylaminophenyl) -1,3,4 Oxadiazole compounds such as oxadiazole, styryl compounds such as 9- (4-diethylaminostyryl) anthracene, carbazole compounds such as polyvinylcarbazole, organic polysilane compounds, 1-phenyl-3- (p-dimethylamino) Pyrazoline compounds such as phenyl) pyrazoline, hydrazone compounds, triphenylamine compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, triazole compounds Nitrogen-containing cyclic compounds such as compounds, condensation Singly or in combinations of two or more such cyclic compounds.
(3) Electron transport agent The electron transport agent used in the present invention includes various compounds having high electron transport ability, such as compounds represented by the following general formulas (ET-1 to ET-17). .

(Wherein R ^e1 , R ^e2 , R ^e3 , R ^e4 and R ^e5 are independent of each other, and are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group or alkoxy group having 1 to 20 carbon atoms, substituted or An unsubstituted aryl group having 6 to 40 carbon atoms or an aralkyl group, or a substituted or unsubstituted phenoxy group.

(In the formula, R ^e6 is a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, R ^e7 is a substituted or unsubstituted alkyl group or alkoxy group having 1 to 20 carbon atoms, or a substituted or unsubstituted carbon group having 6 to 6 carbon atoms. 40 represents an aryl group or an aralkyl group, a halogen atom, or a halogenated alkyl group, and γ represents an integer of 0 to 5. However, when γ is 2 or more, each R ^e7 may be different from each other. )

(In the formula, R ^e8 and R ^e9 are independent of each other, and represent a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms. Δ represents an integer of 1 to 4, and ε represents an integer of 0 to 4. (However, when δ and ε are 2 or more, each R ^e8 and R ^e9 may be different.)

( ^Wherein R ^e10 represents a substituted or unsubstituted alkyl group or alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group or aralkyl group having 6 to 40 carbon atoms, a halogenated alkyl group, or a halogen atom. Ζ represents an integer of 0 to 4, and η represents an integer of 0 to 5. However, when η is 2 or more, each R ^e10 may be different.)

(In the formula, R ^e11 represents a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and σ represents an integer of 1 to 4. However, when σ is 2 or more, each R ^e11 may be different. good.)

( ^Wherein R ^e12 and R ^e13 are independent of each other, a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group or alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon group having 6 to 40 carbon atoms) An aryl group, an aralkyloxycarbonyl group, a hydroxyl group, a nitro group, or a cyano group, and X represents an oxygen atom, = N-CN group, or = C (CN) ₂ group.

( ^Wherein R ^e14 represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group or alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, and R ^e15 represents a halogen ^atom. An atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, an alkoxycarbonyl group, an N-alkylcarbamoyl group, a cyano group, or a nitro group is represented. ^Represents an integer of 0 to 3. However, when λ is 2 or more, each ^{Re 15} may be different from each other.

(In the formula, θ represents an integer of 1 to 2)

(In the formula, R ^e16 and R ^e17 are independent of each other, and represent a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a cyano group, a nitro group, or an alkoxycarbonyl group. Represents an integer of ˜3, provided that when ν or ξ is 2 or more, R ^e16 and R ^e17 may be different from each other.

(In the formula, R ^e18 and R ^e19 are independent of each other, and represent a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, a condensed polycyclic group or a heterocyclic group, and these groups represent a substituent. You may have.)

( ^Wherein R ^e20 represents an amino group, a dialkylamino group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms or an alkoxy group, or a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, and π represents ^Represents an integer of 1 to 2. However, when π is 2, each ^{Re 20} may be different from each other.

(In the formula, R ^e21 represents a hydrogen atom, a substituted or unsubstituted alkyl group or alkoxy group having 1 to 20 carbon atoms, or a substituted or unsubstituted aryl group or aralkyl group having 6 to 40 carbon atoms.)

( ^Wherein R ^e22 represents a halogen atom, a substituted or unsubstituted alkyl group or alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group or aralkyl group having 6 to 40 carbon atoms, an alkoxycarbonyl group, N -Represents an alkylcarbamoyl group, a cyano group, or a nitro group, and μ represents an integer of 0 to 3. However, when μ is 2 or more, each ^{Re 22} may be different from each other.

(Wherein, R ^e23 represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group having 6 to 40 carbon atoms having 1 to 20 carbon atoms, R ^e24 represents a substituted or unsubstituted C 1 -C 20 alkyl group or a substituted or unsubstituted aryl group having 6 to 40 carbon atoms or a group represented by -O-R ^e24,. R ^e24 in the above groups, the above-described substituted or unsubstituted carbon Represents an alkyl group having 1 to 20 carbon atoms or a substituted or unsubstituted aryl group having 6 to 40 carbon atoms.)

(In the formula, R ^e25 , R ^e26 , R ^e27 , R ^e28 , R ^e29 , R ^e30 and R ^e31 are independent of each other, and are substituted or unsubstituted alkyl groups or alkoxy groups having 1 to 20 carbon atoms, substituted or non-substituted. A substituted aryl group having 6 to 40 carbon atoms or an aralkyl group, a halogen atom, or a halogenated alkyl group, χ and φ are the same or different integers of 0 to 4;

( ^Wherein R ^e32 and R ^e33 are independent of each other, a substituted or unsubstituted alkyl group or alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, a halogen atom, Or a halogenated alkyl group, wherein τ and ψ are the same or different and represent an integer of 0 to 4.

( ^Wherein R ^e34 , R ^e35 , R ^e36 and R ^e37 are independent of each other, and are a hydrogen atom, a substituted or unsubstituted alkyl group or alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted carbon number of 6; An aryl group, an aralkyl group, a cycloalkyl group or an amino group of ^˜40 , ^provided that at least two of R ^e34 , R ^e35 , R ^e36 and R ^e37 are the same group which is not a hydrogen atom.
In addition to the above examples, in the present invention, conventionally known electron transport materials, for example, benzoquinone compounds, malononitrile, thiopyran compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroanthracene, etc. , Dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride, dibromomaleic anhydride, etc., alone or in combination.
(4) Binder Resin Various resins conventionally used in the photosensitive layer can be used as the binder resin for dispersing each component. For example, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic copolymer, styrene-acrylic acid copolymer, polyethylene resin, ethylene-vinyl acetate copolymer, chlorinated polyethylene Resin, polyvinyl chloride resin, polypropylene resin, ionomer resin, vinyl chloride-vinyl acetate copolymer, polyester resin, alkyd resin, polyamide resin, polyurethane resin, polycarbonate resin, polyarylate resin, polysulfone resin, diallyl phthalate resin, ketone resin , Polyvinyl butyral resin, polyether resin, polyester resin, etc .; silicone resin, epoxy resin, phenol resin, urea resin, melamine resin, other crosslinkable thermosetting resins; epoxy acrylate DOO, urethane - resin such as photocurable resin such as acrylate can be used.

In particular, a polycarbonate resin is a preferable binder resin because it is excellent not only in transparency and heat resistance but also in mechanical properties and compatibility with a hole transport agent.
(5) Additives In addition to the above-mentioned components, the photosensitive layer has various conventionally known additives such as antioxidants, radical scavengers, singlet quenchers and the like within a range that does not adversely affect the electrophotographic characteristics. Deterioration inhibitors such as char and ultraviolet absorbers, softeners, plasticizers, surface modifiers, extenders, thickeners, dispersion stabilizers, waxes, acceptors, donors, and the like can be blended. In order to improve the sensitivity of the photosensitive layer, a known sensitizer such as terphenyl, halonaphthoquinones, and acenaphthylene may be used in combination with the charge generator.
(6) Mixing ratio and thickness When the electrophotographic photosensitive member of the present invention is a single layer type photosensitive member, the charge generating agent is 0.1 to 50 parts by weight, preferably 100 parts by weight of the binder resin. What is necessary is just to mix | blend in the ratio of 0.5-30 weight part. What is necessary is just to mix | blend the stilbene derivative (hole transport agent) of this invention in the ratio of 20-500 weight part with respect to 100 weight part of binder resin, Preferably it is 30-200 weight part. When the electron transport agent is contained, the ratio of the electron transport agent is 5 to 100 parts by weight, preferably 10 to 80 parts by weight with respect to 100 parts by weight of the binder resin.

  In addition, when the electrophotographic photoreceptor of the present invention is a laminated photoreceptor, the charge generator and the binder resin constituting the charge generation layer can be used in various ratios, but the binder resin 100 can be used. It is appropriate to mix the charge generating agent in an amount of 5 to 1000 parts by weight, preferably 30 to 500 parts by weight with respect to parts by weight. In the case where a hole transport agent is contained in the charge generation layer, the ratio of the hole transport agent is 10 to 500 parts by weight, preferably 50 to 200 parts by weight with respect to 100 parts by weight of the binder resin. .

The hole transport agent constituting the charge transport layer and the binder resin can be used in various proportions within a range not inhibiting charge transport and not crystallizing, but are generated in the charge generation layer by light irradiation. The stilbene derivative (hole transport agent) of the present invention is blended in an amount of 10 to 500 parts by weight, preferably 25 to 200 resins, with respect to 100 parts by weight of the binder resin so that the charges can be easily transported. Is appropriate. When the electron transporting agent is contained in the charge transporting layer, the ratio of the electron transporting agent is 5 to 200 parts by weight, preferably 10 to 100 parts by weight with respect to 100 parts by weight of the binder resin.
(7) Structure Further, the thickness of the photosensitive layer in the single layer type photoreceptor is 5 to 100 μm, preferably 10 to 50 μm. The thickness of the photosensitive layer in the multilayer photoreceptor is about 0.01 to 5 μm, preferably about 0.1 to 3 μm for the charge generation layer, and about 2 to 100 μm, preferably about 5 to 50 μm for the charge transport layer. .

  As the conductive substrate on which such a photosensitive layer is formed, various materials having conductivity can be used. For example, iron, aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, Examples thereof include metals such as cadmium, titanium, nickel, palladium, indium, stainless steel, and brass, plastic materials on which the above metal is vapor-deposited or laminated, glass coated with aluminum iodide, tin oxide, indium oxide, and the like.

Further, the shape of the conductive substrate may be any of a sheet shape, a drum shape, or the like in accordance with the structure of the image forming apparatus to be used. The substrate itself is conductive or the surface of the substrate is conductive. As long as it has. The conductive substrate preferably has sufficient mechanical strength when used. When the photosensitive layer is formed by a coating method, the charge generator, charge transport agent, binder resin and the like exemplified above, together with a suitable solvent, a known method such as a roll mill, ball mill, attritor, paint shaker, super A dispersion liquid may be prepared by dispersing and mixing using a sonic disperser or the like, and this may be applied and dried by a known means.
(8) Manufacturing method Various organic solvents can be used as a solvent for producing the dispersion, for example, alcohols such as methanol, ethanol, isopropanol and butanol; aliphatic systems such as n-hexane, octane and cyclohexane. Hydrocarbons: aromatic hydrocarbons such as benzene, toluene, xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride, chlorobenzene; ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether Ketones such as acetone, methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate and methyl acetate; dimethylformaldehyde, dimethylformamide, dimethylsulfo Sid and the like. These solvents are used alone or in admixture of two or more.

  Further, a surfactant, a leveling agent or the like may be used in order to improve the dispersibility of the charge transport agent or charge generator and the smoothness of the photosensitive layer surface.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.
Hereinafter, the present invention will be described with reference to synthesis examples, examples and comparative examples.
[Example 1]
(1) Synthesis of Stilbene Derivative (1) -1 Synthesis of Triphenylamine Derivative Synthesis of a triphenylamine derivative represented by the following formula (13) was carried out according to the following reaction formula (4).
That is, 152.0 g (1.10 mol) of anhydrous potassium carbonate and 9.5 g (0.15 mol) of powdered copper copper were added into a two-necked flask having a volume of 500 ml, heated for 2 hours, and stirred until uniform. did. Next, after cooling to room temperature, 67.6 g (0.5 mol) of an aniline compound represented by the following formula (12) and 305.9 g (1.5 mol) of iodobenzene were added, and then reheated to 220 ° C. And allowed to react for 2.5 hours. Then, after cooling to room temperature, 100 ml of toluene was added and filtered. The obtained residue was dissolved in toluene and dried using activated clay. Thereafter, the residue was dissolved in toluene, and methanol was further added for crystallization. Thereafter, the residue was dissolved again with toluene, and methanol was further added to cause crystallization. The obtained crystals were separated by filtration and dried. Thereafter, the obtained crystal was purified using silica gel column chromatography (developing solvent: chloroform / hexane solvent) to obtain 79.3 g of a triphenylamine derivative represented by the formula (13) (yield: 55. 2%).
Reaction formula (4):

(1) -2 Synthesis of formylated triphenylamine derivative Subsequently, a formylated triphenylamine derivative represented by the formula (14) was synthesized according to the following reaction formula (5).

That is, in a 500 ml flask, 60 g (0.21 mol) of a triphenylamine derivative represented by the formula (13), 450 ml of dimethylformamide (DMF), 41.8 g (0.27 mol) of oxychlorophosphoric acid, And stirred at 85 ° C. or higher for 3 hours. After the reaction, the reaction solution was dropped into 600 ml of ion-exchanged water, and the precipitated solid was filtered off. The obtained solid was stirred and washed with ion-exchanged water. Thereafter, the solid was dissolved in toluene, and the organic layer was washed 5 times with ion-exchanged water. Then, anhydrous sodium sulfate and activated clay were added to the obtained organic layer, followed by drying and adsorption treatment. Thereafter, toluene was distilled off under reduced pressure, and the residue was dissolved in 200 ml of toluene and crystallized from methanol to obtain 51.4 g of a formylated triphenylamine derivative represented by the formula (14) (yield 77.6). %).
Reaction formula (5):

(1) -3 Synthesis of diphosphate ester derivative Preparation of the diphosphate ester derivative represented by the formula (17) was made according to the following reaction formula (6). That is, after adding 100 g (0.8 mol) of dichlorobutene in a flask having a volume of 500 ml, 319 g (1.92 mol) of triethyl phosphite was added and reacted at 180 ° C. for 8 hours. Subsequently, after cooling to room temperature, excess phosphorous acid triethyl ester was distilled off under reduced pressure. The obtained white residue was washed with n-hexane and vacuum-dried to obtain 223 g of a diphosphate derivative represented by the formula (30) (yield 85%).
Reaction formula (6):

(1) -4 Synthesis of stilbene derivatives
Subsequently, the synthesis | combination of the stilbene derivative represented by Formula (2-1) of Table 1 mentioned above was implemented along following Reaction formula (7). That is, in a 500 ml two-necked flask, 8.2 g (0.025 mol) of the diphosphate ester represented by the formula (17) obtained in (1) -3 was added and purged with argon. , NaOMe 4.8 g (0.025 mol) / THF 30 ml were accommodated and stirred for 30 minutes. Next, 16 g (0.051 mol) of the formylated triphenylamine derivative represented by the above formula (16) was dissolved in this container, and then stirred at room temperature for about 12 hours. Next, the reaction solution was poured into 500 ml of ion-exchanged water, and the aqueous layer was changed from neutral to weakly acidic with dilute hydrochloric acid. Furthermore, toluene extraction was performed and the organic layer was washed 5 times with ion exchange water. Thereafter, the organic layer was dried over anhydrous magnesium sulfate, and the solvent was distilled off. The obtained residue was purified by silica gel chromatography (developing solvent: chloroform / hexane) to obtain 12.4 g of a stilbene derivative represented by the formula (9) (yield 76%).
Reaction formula (7):

(2) Evaluation of crystallization and measurement of electrical characteristics (initial surface potential, half-exposure amount and residual potential) Using the obtained stilbene derivative as a hole transporting agent, a single layer type electrophotographic photosensitive member was prepared, and the photosensitive member The initial crystallization potential, half-exposure dose, and residual potential were measured as electrical property evaluation. That is, 60 parts by weight of the obtained stilbene derivative as a hole transport agent, 5 parts by weight of an X-type metal-free phthalocyanine (CGM-1) represented by the following formula as a charge generator, and a binder resin 100 parts by weight of a polycarbonate (Resin-1) resin represented by the following formula was added to 800 parts by weight of tetrahydrofuran as a solvent. Subsequently, it was mixed and dispersed for 50 hours using a ball mill to prepare a coating solution for a single-layer type photosensitive layer. The obtained coating solution is applied on a conductive substrate (aluminum base tube) by a dip coating method and dried with hot air at 100 ° C. for 30 minutes to form a single-layer type photosensitive layer having a thickness of 25 μm. An electrophotographic photosensitive member was obtained.

Subsequently, the crystallization state of the obtained electrophotographic photosensitive member was observed, and further, the initial electrical characteristics, that is, the half exposure amount (E _1/2 ) and the residual potential (V _r ) were measured with a drum sensitivity tester (produced by GENTEC). ) And charged so that the surface potential was 710V. As for the half-exposure dose (E _1/2 ), monochromatic light having a wavelength of 780 nm (half-value width: 20 nm, light intensity: 1.5 μJ / cm ² ) extracted from the light of the halogen lamp using a bandpass filter is exposed. Then, the time required for the surface potential to be halved was measured. Furthermore, as for the residual potential, the surface potential at the time when 330 msec passed from the start of exposure was measured and used as the residual potential.

    The obtained results are shown in Table 2.

  Evaluation of crystallization: ○ No crystallization, × Crystallization can be visually confirmed.

As is clear from the results, it was confirmed that the obtained electrophotographic photosensitive member had a low residual potential value, a half exposure amount of 0.9 seconds or less, and a predetermined sensitivity.
CGM-1:

Resin-1:

[Example 2] A single layer was formed in the same manner as in Example 1 except that 30 parts by weight of a quinone derivative (ET-A) represented by the following formula was added as an electron transport material to the coating liquid of Example 1. A mold photosensitive layer was prepared and evaluated.

  ET-A:

[Example 3] A single-layer type photosensitive material as in Example 1 except that 30 parts by weight of a quinone derivative (ET-B) according to the following formula was further added as an electron transport material to the coating solution in Example 1. Layers were created and evaluated.
ET-B:

  [Example 4] In the same manner as in Example 1, except that another 30 parts by weight of another quinone derivative (ET-C) represented by the following formula was added as an electron transporting material to the coating liquid in Example 1. A single-layer type photosensitive layer was prepared and evaluated.

  [Examples 5 to 8] Example 1 was used except that instead of the stilbene derivative (2-1) in Example 1, the stilbene derivative (2-2) in Table 1 described above was used as the hole transport material. A single-layer type photosensitive layer was prepared and evaluated in the same manner as in.

  [Examples 9 to 12] Example 1 was used except that instead of the stilbene derivative (2-1) in Example 1, the stilbene derivative (3-1) in Table 1 described above was used as the hole transport material. A single-layer type photosensitive layer was prepared and evaluated in the same manner as in.

  Examples 13 to 16 Example 1 was used except that the stilbene derivative (2-4) in Table 1 described above was used as the hole transport material instead of the stilbene derivative (2-1) in Example 1. A single-layer type photosensitive layer was prepared and evaluated in the same manner as in.

  [Examples 17 to 20] Instead of the stilbene derivative (2-1) in Example 1, the stilbene derivative (1-1) in Table 1 described above was used as the hole transport material, except that the examples 1 to 1 were used. A single-layer type photosensitive layer was prepared and evaluated in the same manner as in Example 4.

  [Comparative Example 1] Similar to Example 1 except that instead of the stilbene derivative (2-1) in Example 1, a stilbene derivative represented by the following formula (HT-A) was used as the hole transport material. A single-layer type photosensitive layer was prepared and evaluated.

    [Comparative Example 2] A single-layer type photosensitive layer as in Example 1 except that the stilbene derivative (HT-B) was used as the hole transport material instead of the stilbene derivative (2-1) in Example 1. Was created and evaluated.

As is apparent from the table, the electrophotographic photoreceptors of Examples 1 to 20 had a small absolute value of the residual potential Vr, and a good value was also obtained for the half-exposure amount E1 _{/ 2} . On the other hand, the electrophotographic photosensitive member of the comparative example was crystallized and the electrical characteristics could not be evaluated.

Claims (6)

General formula (1):

(Wherein R ₁ and R ₂ are the same or different and each represents an optionally substituted alkyl group having 1 to 8 carbon atoms or an optionally substituted aryl group having 1 to 20 carbon atoms. R _{3 to} R ₁₄ are the same or different and are a hydrogen atom, an alkyl group having 1 to 8 carbon atoms which may have a substituent, or an alkoxy group having 1 to 8 carbon atoms which may have a substituent. Or an aryl group having 1 to 20 carbon atoms which may have a substituent, m represents an integer of 2 to 5.), and a stilbene derivative.
The stilbene derivative according to claim 1, wherein R ₁ and R ₂ in the general formula (1) are alkyl groups having 1 to 8 carbon atoms. General formula (2a):

And general formula (2b):

(Wherein R ₁ and R ₂ are the same or different and each represents an optionally substituted alkyl group having 1 to 8 carbon atoms or an optionally substituted aryl group having 1 to 20 carbon atoms. R _{3 to} R ₁₄ are the same or different and are a hydrogen atom, an alkyl group having 1 to 8 carbon atoms which may have a substituent, or an alkoxy group having 1 to 8 carbon atoms which may have a substituent. Or an aryl group having 1 to 20 carbon atoms which may have a substituent.) A formylated triphenylamine derivative represented by general formula (3):

(N represents an integer of 0 to 3)
2. The method for producing a stilbene derivative according to claim 1, wherein a diphosphate derivative represented by the formula: The formylated triphenylamine derivative (2a) is represented by the general formula (4a):

(In the formula, R ₁ represents an alkyl group having 1 to 8 carbon atoms which may have a substituent or an aryl group having 1 to 20 carbon atoms which may have a substituent, and R ₃ and R ₄ represent The same or different, having a hydrogen atom, an optionally substituted alkyl group having 1 to 8 carbon atoms, an optionally substituted alkoxy group having 1 to 8 carbon atoms, or a substituent; Or an aryl group having 1 to 20 carbon atoms.) The aniline derivative represented by formula (5a) is reacted with at least one iodobenzene derivative which may have a substituent.

(In the formula, R ₁ represents an optionally substituted alkyl group having 1 to 8 carbon atoms or an optionally substituted aryl group having 1 to 20 carbon atoms, R _{3 to} R _7; R ₁₃ is the same or different and represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms which may have a substituent, an alkoxy group having 1 to 8 carbon atoms which may have a substituent, or a substituent. An aryl group having 1 to 20 carbon atoms which may be present.) And then formylating this compound (5a) by the Vilsmeier method. Furthermore, the formylated triphenylamine derivative (2b) is represented by the general formula (4b):

(Wherein R ₂ represents an alkyl group having 1 to 8 carbon atoms which may have a substituent or an aryl group having 1 to 20 carbon atoms which may have a substituent, and R ₈ and R ₉ are The same or different, having a hydrogen atom, an optionally substituted alkyl group having 1 to 8 carbon atoms, an optionally substituted alkoxy group having 1 to 8 carbon atoms, or a substituent; Or an aryl group having 1 to 20 carbon atoms.) Is reacted with at least one iodobenzene derivative which may have a substituent, and the general formula (5b):

(In the formula, R ₂ represents an alkyl group having 1 to 8 carbon atoms which may have a substituent or an aryl group having 1 to 20 carbon atoms which may have a substituent, and R _{8 to} R _12, R ₁₄ may be the same or different and each represents a hydrogen atom, an optionally substituted alkyl group having 1 to 8 carbon atoms, an optionally substituted alkoxy group having 1 to 8 carbon atoms, or a substituent. An aryl group having 1 to 20 carbon atoms that may be present.) And then formylating this compound (5b) by the Vilsmeier method. The manufacturing method of the stilbene derivative of Claim 3 which is a thing. An electrophotographic photosensitive member provided with a photosensitive layer on a conductive substrate, wherein the photosensitive layer contains a stilbene derivative represented by the general formula (1) according to claim 1 or claim 2. An electrophotographic photoreceptor. The photosensitive layer is a single-layer type photosensitive layer containing a stilbene derivative represented by the general formula (1) according to claim 1 or 2 together with a charge generating agent and an electron transporting agent. Electrophotographic photoreceptor.