JPS605941B2 - Electrophotographic photoreceptor - Google Patents

Description

[Detailed description of the invention] The present invention relates to an electrophotographic photoreceptor.

Specifically, the present invention relates to a highly sensitive electrophotographic photoreceptor having a photosensitive layer containing an organic photoconductive substance. Conventionally,
Inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been widely used in the photosensitive layer of electrophotographic photoreceptors.

In recent years, research has progressed on the use of organic photoconductive substances, typified by polyvinylcarbazole, in photosensitive layers of electrophotographic photoreceptors, and some of them have been put into practical use. Organic photoconductive materials are lighter and easier to form into films than inorganic materials. It has the advantage that photoreceptors can be easily manufactured, and depending on the type, transparent photoreceptors can be manufactured. Although they have many advantages, organic photoconductive materials have not been widely used in electrophotographic photoreceptors because they are inferior to inorganic materials in terms of sensitivity and durability. Ta. Therefore, the present inventors conducted intensive research on organic photoconductive materials that provide electrophotographic photoreceptors with high sensitivity and high durability, and discovered that a specific pisazo compound was suitable, and arrived at the present invention. did. That is, the gist of the present invention is general formula (1) or general formula (b) [wherein, R represents a hydrocarbon residue which may have a substituent, and D represents -Ar-... group or -Ar-Y-- group (wherein, Ar is a phenylene group which may have a substituent, Y is a divalent hydrocarbon residue which may have a substituent, 〇- group, group, one CONH- group, -S- group, one S-
The present invention relates to an electrophotographic photoreceptor having a photosensitive layer containing a bisazo compound represented by S- group, one SO- group, one S02 group, or one NH- group.

The present invention will be described in detail below. The electrophotographic photoreceptor of the present invention contains a bisazo compound represented by the general formula (1) or (b) in the photosensitive layer.

In the above general formulas (1) and (b), R is a hydrocarbon residue that may have a substituent, and specifically, a methyl group, an ethyl group, a straight mirror-like or a branched group. propyl group,
Alkyl groups such as butyl group, bentyl group, hexyl group; hydroxyalkyl group, alkoxyalkyl group, alkoxycarbonylalkyl group, acyloxyalkoxyalkyl group, hydroxyalkoxyalkyl group, alkoxyalkoxyalkyl group, aryloxyalkyl group,
Such as acyloxyalkyl group, cyanoalkyl group, aminoalkyl group, NON-dialkylaminoalkyl group, alkylaminoalkyl group, halogenated alkyl group, carboxyalkyl group, morpholinoalkyl group, alkylthioalkyl group, arylthioalkyl group, etc. Alkyl group having a substituent; cycloalkyl group such as cyclohexyl group; aralkyl group such as penzyl group, phenethyl group; phenyl group, chlorphenyl group, methoxyphenyl group, nitrophenyl group, tolyl group, xylyl group, alkyl group Examples include aryl groups such as aminophenyl groups. Furthermore, in the general formulas (1) and (b),
D is -Ar-Ar- group or -~1Y-~1 group.

Ar is a phenylene group which may have a substituent, and the substituents include alkyl groups such as methyl group and ethyl group; halogen atoms such as chlorine atom and bromine atom; alkoxy groups such as methoxy group and ethoxy group. Groups; Acyl groups such as acetyl and benzoyl; Alkylthio groups such as methylthio and ethylthio; Arylthio groups such as phenylthio; Alkylsulfinyl groups such as methylsulfinyl and ethylsulfinyl; methylsulfonyl and ethyl Examples thereof include alkylsulfonyl groups such as sulfonyl groups; arylsulfonyl groups such as phenylsulfonyl groups, sulfonic acid groups, sulfinic acid groups, and groups consisting of salts of these acids. Furthermore, Y may have a substituent 2
a valent hydrocarbon residue, 10-group, 1-CON group, 1S- group, 1S-S- group, 1SO- group, 1SQ- group or -NH- group, but the substituent The divalent hydrocarbon residue which may have -CH2- group, one CH=CH-
group, -CH=CBr- group, and the like.

A particularly suitable D is represented by the following formula. Of course, in the above formula, the phenylene group may have a substituent as exemplified above.

In the general formulas (1) and (b), the aromatic nucleus of the naphthalic acid imide bone core portion may also have an appropriate substituent,
Suitable substituents include halogen atoms, nitro groups, and the like.

The pisazo compounds represented by the general formulas (1) and (0) can be produced according to known methods (Japanese Patent Publication No. 36-19083 and Japanese Patent Publication No. 49-12127).

For example, 4-1- or 3-hydroxynaphthalic acid imide represented by the general formula (m) or the general formula (W) (wherein R has the same meaning as the general formulas (1) and (0)), General formula (V)4N-D-NH2...
- (V) (wherein D has the same meaning as general formulas (1) and (b)) can be produced by coupling reaction with a tetrazonium salt of an aromatic diamine.

Substituents on the nucleus of the coupling component and the tetrazo component may be provided before the coupling reaction, or after the coupling reaction, for example, halogenation, nitration,
It may be provided by performing acylation or the like. The electrophotographic photoreceptor of the present invention has a photosensitive layer containing one or more bisazo compounds represented by the general formula (1) or (0).

Various forms of photosensitive layers are well known, and the photosensitive layer of the electrophotographic photoreceptor of the present invention may be any of them. Usually, the photosensitive layer is of the type exemplified below. '11 Photosensitive layer consisting of a bisazo compound ■ Photosensitive layer in which a bisazo compound is dispersed in a binder {3' Photosensitive layer in which a bisazo compound is dispersed in a well-known charge transfer medium ■ Photosensitive layer in the above {1} to [31] A photosensitive layer comprising a charge generation layer and a charge transfer layer containing a well-known charge transfer medium laminated thereon.The compound represented by the general formula (1) or (0) above generates charge carriers with extremely high efficiency when it absorbs light. do.

Although the generated carriers can be transferred using a bisazo compound as a medium, it is preferable to use a known charge transfer medium as a medium. From this point of view, the photosensitive layers in the form '3' and '3' are particularly preferred. Charge transfer media are generally classified into two types: electron transfer media and hole transfer media, and both can be used in the photosensitive layer of the photoreceptor of the present invention, and a mixture thereof can also be used.

As an electron transfer medium, an electron-withdrawing compound having a nitro group or a letron-attracting group such as a cyano group or an ester group, such as 2,4,7-trinitrofluorenone, 2,4,5,7
- Tetranit. Examples include nitrated fluorenone such as fluorenone or tetracyanoquinodimethane. In addition, an electron-donating organic photoconductor is used as a hole transport medium.
compounds, such as heterocyclic compounds such as carbazole, indole, imidazole, oxadiazole, pyrazole, pyrazoline, and thiadiazole, derivatives of aniline, or polymers having a group consisting of these compounds in the king chain or side chain (polyvinyl carbazole, polyglycidyl carbazole) and the like. Among them, the following general formula (
W) (wherein Arl, ~2 and ~3 represent an aromatic hydrocarbon residue or an aromatic compound ring group which may have a substituent, and n represents 0 or 1) Particularly preferred are the birazoline compounds shown in Table 1.

The electrophotographic photoreceptor of the present invention can be manufactured according to a conventional method.

For example, an electrophotographic photoreceptor having a photosensitive layer of type '1' may be prepared using a coating solution obtained by dissolving or dispersing the bisazo compound represented by the general formula (1) or (n) in an appropriate medium. It can be manufactured by coating on a conductive support and drying to form a photosensitive layer having a thickness of usually several to several tens of degrees. Media for preparing the coating solution include basic solvents that dissolve bisazo compounds such as butylamine and ethylenediamine; ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as methyl ethyl ketone and cyclohexanone; carbonized aromatic compounds such as toluene and xylene. Hydrogen; Aprotic polar solvents such as N/N-dimethylformamide, acetonitrile, N-methylpyrrolidone, dimethyl sulfoxide; methanol, ethanol,
Alcohols such as isopropanol; esters such as ethyl acetate, tertyl formate, methyl cellosolve acetate;
Examples include media for dispersing bisazo compounds such as chlorinated hydrocarbons such as dichloroethane and chloroform. When using a medium for dispersing the bisazo compound, the bisazo compound can be dispersed in 5 degrees or less, preferably 3 degrees or less, and optimally 1 degree or less.
〃It is necessary to make the particles into fine particles. Further, as the conductive support on which the photosensitive layer is formed, any of those employed in well-known electrophotographic photoreceptors can be used. Specific examples include metal drums and sheets made of aluminum, copper, etc., and laminates and vapor deposits of these metal foils. Further examples include plastic films, paper, etc., which are coated with a conductive material such as metal powder, carbon black, copper iodide, or polymer electrolyte together with a suitable binder to conductivity treatment. If the binder is dissolved in the coating liquid used to form the photosensitive layer of the type '1', the {
Electrophotographic photoreceptors having 21 types of photosensitive layers can be manufactured.

In this case, the medium of the coating liquid is preferably one that dissolves the binder. As binders, various polymers such as polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, ester acrylate, and ester methacrylate, phenoxy resin, polysulfone, polycarbonate, polyester, cellulose ester, urethane resin, and epoxy resin are used. Can be mentioned. The amount of binder used is usually 0.1 to 5 times the weight of the bisazo compound. In forming this type of photosensitive layer, it is preferred that the bisazo compound be present in the binder in the form of fine particles of, for example, 3 or less particles, particularly 1 or less particles. Similarly, if a charge transfer medium is dissolved in the coating liquid used to form the photosensitive layer of the type '1} above, it is possible to produce an electrophotographic photoreceptor having the photosensitive layer of the glue type. can.

As the charge transfer medium, any of those exemplified above can be used. Apart from charge transport media which can themselves be used as binders, such as polyvinylcarbazole and polyglycidylcarbazole, it is preferred to use other binders. As the binder, any of those exemplified above can be used. In this case, the amount of the binder used is usually 6 to 1000 times the weight of the pisazo compound, and the amount of the charge transfer medium used is usually 0.2 to 1.5 times the weight of the binder, preferably 0.
It is in the range of 3 to 1.2 times the weight. In the case of a charge transport medium which itself can be used as a binder, a weight ratio of 5 to 10% relative to the bisazo compound is usually employed. In this type of photosensitive layer, similarly to the photosensitive layer of type [3'], it is preferable that the bisazo compound is present in the charge transport medium and the binder in the form of fine particles. If a coating solution obtained by dissolving a charge transfer medium in a suitable medium is applied onto the photosensitive layer of the type m to 1, and dried to form a charge transfer layer, a photosensitive layer of the type {41 is obtained. An electrophotographic photoreceptor can be manufactured.

In this case, the photosensitive layer of the '11-Mari type described above serves as a charge generation layer. The charge transfer layer does not need to be provided above the charge generation layer, but may be provided between the charge generation layer and the conductive support. However, the former is preferable in terms of durability.
The charge transfer layer is formed at the same time as the photosensitive layer described in Section 3 above. That is, the coating liquid for forming the photosensitive layer of [31] above, except that the bisazo compound is removed, may be used as the coating liquid. Usually the charge generation layer is 0.01
The charge transfer layer is 5-30 mm thick. Of course, the photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a known sensitizer. Suitable sensitizing agents include Lewis acids and dyes that form charge-transferring bodies with organic photoconductive materials. Examples of Lewis acids include quinones such as chloranil, 2,3-dichloro-1,4-naphthoquinone, 2-methylanthraquinone, 1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone, 2-chloroanthraquinone, and phenanthrenequinone; 4-
Aldehydes such as nitrobenzaldehyde, ketones such as 9-penzoylanthracene, indandione, 3,5-dinitrobenzophenone, 3,3',5,5-tetranitrobenzophenone, phthalic anhydride, 4-clonaphthalic anhydride acid anhydrides, tetracyanoethylene,
Cyano compounds such as terephthalalmalononitrile and 4-nitrobenzalmalononitrile; 3-pensulfthalide,
3-(Q-cyano pnitrobenzal)phthalide, 3
1 (Q-cyano-p nitrobenzal) 4, 5, 6, 7
Examples include electron-withdrawing compounds such as phthalides such as monotetrachlorphthalide. Examples of 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. In addition, inorganic photoconductive fine particles such as selenium and selenium-arsenic alloy; organic photoconductive pigments such as copper phthalocyanine and thioindigo may also be contained. 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.

As plasticizers, phthalate ester, phosphate ester,
Examples include aromatic compounds such as epoxy compounds, chlorinated paraffins, chlorinated fatty acid esters, and methylnaphthalene. It goes without saying that, if necessary, it may have an adhesive layer, an intermediate layer, and a transparent insulating layer like a commercially available electrophotographic photoreceptor. The electrophotographic photoreceptor of the present invention has been described in detail above, and the photoreceptor of the present invention is characterized by extremely high sensitivity and excellent durability.

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. In addition, "parts" in the examples indicate "parts by weight." Example 1 A bisazo compound having the above structure was dispersed in tetrahydrofuran and atomized using a sand grinder.

This bisazo compound part, 10 parts of 5-(p-dimethylaminophenyl)-11,3-diphenyl-2-pyrazoline, and 10 parts of cellulose acetate butyrate (manufactured by Eastman Co., butyryl content 17%) were mixed with tetrahydrofuran. A coating solution was prepared by dissolving or dispersing 100 base portions. This coating solution was applied to a grained aluminum plate using a baker applicator, and when it dried, a thick ior
An electrophotographic photoreceptor having a photosensitive layer was obtained. When the sensitivity, that is, the half-decreased exposure (EI'2) of this photoreceptor was measured, it was 121 ux·sec.

The half-decreased exposure amount is determined by first charging the photoreceptor in a gambling place by Juro V's corona discharge, then exposing it to white light, and measuring the amount of exposure required for the surface potential to attenuate to half of the initial surface potential. Ta. Example 2 In Example 1, 5
A photoreceptor was produced in exactly the same manner except that 2,4,7-trinitrofluorenone was used in place of -(p-dimethylaminophenyl)-1,3-diphenyl-2-pyrazoline.

The EI'2 of this photoreceptor was approximately 28.Sec.

In this case, it was charged with Ichiro V. Examples 3-1
2 1 part of a bisazo compound having a structure corresponding to the above general formula (skin) in which R and D are shown in Table 1 was added to 10 $ of tetrahydrofuran and dispersed using ultrasound.

This dispersion was applied with a baker applicator to a wet film thickness of 20 mm onto a 10 mm thick aluminum foil laminated to a 75 mm thick polyethylene terephthalate film, and then dried. On the charge generation layer thus obtained, 10 parts of 1,3-diphenyl-(5-p-methoxyphenyl)-2-pyrazoline and 1 part of polycarbonate (manufactured by Mitsubishi Gas Chemical Co., Ltd., trademark: Upilon S-1000) were added.
A charge transfer layer was formed by applying a solution prepared by dissolving 100% of tetrahydrofuran to a dry film thickness of 10%. In this way, an electrophotographic photoreceptor having two photosensitive layers was obtained. The EI/2 of this photoreceptor is shown in Table 1.

Further, the exposure amount (EI/5) required for the surface potential to attenuate to 1'5 of the initial potential was measured and is also shown in Table 1.
In this case, it was charged with Ichiro V. Table 1 Examples
13 In Example 3, 5-(p-dimethylaminophenyl)-3-(p-dimethylaminostyryl)-1-phenyl-2-pyrazoline was used instead of 1,3-diphenyl-5-(p-methoxyphenyl)-12-pyrazoline. An electrophotographic photoreceptor having a two-layer photosensitive layer was produced in exactly the same manner as in Example 3, except that .

The EI/2 of this photoreceptor is 2. $blood/sec, EI'5 was 59 views/sec.

Example 14 1 part of the pisazo compound used in Example 11 was added to 100 parts of methyl ethyl ketone and dispersed by ultrasonication.

Polyester (manufactured by Toyobo Co., Ltd., trademark Byron 200)
) was added and applied to the aluminum surface of an aluminum-laminated polyester film in the same manner as in Example 3 to form a charge generation layer. A charge transfer layer was formed on this charge generation layer in the same manner as in Example 3 to obtain an electrophotographic photoreceptor having a two-layer photosensitive layer. When this photoreceptor was set in an electrophotographic copying machine (trade name: UBix-800, manufactured by Konishiroku Photo Industry Co., Ltd.) and a document was copied, a clear image without fogging was obtained.

Example 15 On the charge generation layer prepared in Example 11, polyvinylcarbazole (manufactured by Takasago Co., Ltd., trademark Tuvicol-
210) A solution prepared by dissolving 1 part of chlorinated paraffin and 2 parts of 40% chlorinated paraffin in 10 parts of tetrahydrofuran was applied and dried to form a charge transfer layer to a dry thickness of 10 mu.

Claims (1)

[Claims] 1 General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ Or general formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R has a substituent. D represents an -Ar-Ar- group or -Ar-Y-Ar-
represents a group (in the formula, Ar is a phenylene group that may have a substituent, Y is a divalent hydrocarbon residue that may have a substituent, -O- group, ▲ mathematical formula, chemical formula, There are tables, etc. ▼ Group, -CONH- group, -S- group, -S-S- group, -SO
- group, -SO_2- group, or -NH- group).