JPH04120550A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body which is high in sensitivity and low in residual potential by incorporating a pyrrolopyrole compd., hydrazone compd. and/or hydrazone compd. which are respectively specific into a photosensitive layer. CONSTITUTION:The pyrrolopyrole compd. expressed by formula I and the hydrozone compd. expressed by formula II and/or the hydrozone compd. expressed by formula III are incorporated into the photosensitive layer. In the formulas I to III, R1, R2 denote an aryl group which may have a substituent, aralkyl group, etc.; R3, R4 denote a hydrogen group, alkyl group, etc.; R5, R6 denote an alkyl group, aralkyl group, etc.; R7 denotes a prehnyl group, isoamyl group, etc.; R8, R9 denote an aralkyl group, aryl group which may have a substituent. The electrophotographic sensitive body which has the excellent photostability, good sensitivity and low residual potential is obtd. in this way.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an electrophotographic photoreceptor suitably used in an image forming apparatus such as a copying machine. ) In recent years, electrophotographic photoreceptors in image forming devices such as copying machines have been used as electrophotographic photoreceptors that have a large degree of freedom in functional design. Among them, charge-generating materials that generate electric charges when irradiated with light, and charge-transporting materials that transport the generated electric charges. For example, a single-layer photosensitive layer containing a charge generating material, a charge transporting material, and a binder resin, or a charge generating layer containing the charge generating material, a charge transporting material, and a binder resin. A functionally separated electrophotographic photoreceptor has been proposed, which includes a laminated photosensitive layer in which a charge transport layer containing a charge transport layer is laminated.

Further, when forming a copy image using an electrophotographic photoreceptor, the Carlson process is widely used. The Carlson process consists of a charging process in which a photoconductor is uniformly charged by corona discharge, an exposure process in which an original image is exposed to light on the charged photoconductor to form a static latent image corresponding to the original image, and an electrostatic latent image. a developing step of developing with a developer containing toner to form a toner image, a transfer step of transferring the toner image to a base material such as paper, and a fixing step of fixing the toner image transferred to the base material. After the transfer process, the basic process includes a cleaning process to remove toner remaining on the photoreceptor.In order to form a high-quality image in the above-mentioned Carlson process, the electrophotographic photoreceptor must have sufficient charging characteristics and photosensitive characteristics. It is required to have excellent characteristics and a low residual potential after exposure.

On the other hand, the electrophotographic properties of the functionally separated electrophotographic photoreceptor are largely influenced by the combination of the charge generating material and the charge transporting material. For example, pyrrolopyrrole compounds proposed as charge-generating materials (Japanese Patent Laid-Open No. 61-1625
No. 55) and N-ethyl-3-carbazolylaldehye)
In an electrophotographic photoreceptor having a photoreceptor layer combining ``-NN diphenylhydrazone, the hydrazone compound has a large electric field intensity dependence regarding drift mobility, a high residual potential of the photoreceptor, and sufficient sensitivity. Moreover, since the above hydrazone compounds are easily photoisomerized by light irradiation, their photostability is still insufficient, and there are problems in that sensitivity decreases and residual potential increases with repeated use.

On the other hand, N,N-diethylaminohenzaldehyde diphenylhydrazone is known as a charge transport material having superior photostability compared to the above-mentioned N-ethyl-3-calhazolyl aldehyde N,N-diphenylhydrazone. However, although an electrophotographic photoreceptor having a photosensitive layer in combination with the above-mentioned pyrrolopyrrole compound can achieve photostability, it still has the problem that the residual potential of the photoreceptor is high and the sensitivity is not sufficient.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an electrophotographic photoreceptor having excellent photostability, high sensitivity, and low residual potential.

(Means and effects for solving the problems) The present invention has the following features:
In a photoreceptor in which a photosensitive layer is formed on a conductive substrate, the photosensitive layer comprises a pyrrolopyrrole compound represented by the following general formula [■], a hydrazone compound represented by the following general formula (II), and The above object was achieved by containing the hydrazone compound represented by the general formula (III).

(In the formula, R1 and R2 are the same or different, and are an aryl group or an aralkyl group that may have a substituent,
It represents a heterocyclic group, and R3 and R4 are the same or different and represent a hydrogen atom, an alkyl group, or an aryl group which may have a substituent. ) (In the formula, R3 and R, which are the same or different, represent an alkyl group, an aralkyl group, or an aryl group that may have a substituent, and R7 represents a prenyl group, an isoamyl group, or a benzyl group.) (In the formula, and R9 are the same or different and represent an aralkyl group or an aryl group which may have a substituent.) As a result of intensive research, the present inventors have developed a charge-generating material represented by the general formula (1). In an electrophotographic photoreceptor having a photosensitive layer containing a pyrrolopyrrole compound, a hydrazone compound represented by general formula (II) and/or a hydrazone represented by general formula CI[l] is used as a charge transport material. It has been found that when these compounds are combined, an electrophotographic photoreceptor with excellent photostability, high sensitivity, and low residual potential can be obtained.

(Preferred Embodiment) The electrophotographic photoreceptor of the present invention includes a binder resin, a pyrrolopyrrole compound represented by the above general formula [I] as a charge generating material, and the above general formula CIN and/or as a charge transport material.
Alternatively, a photosensitive layer is formed by preparing a coating solution by mixing the hydrazone compound represented by the general formula CI [[) with a solvent, etc., coating this coating solution on a conductive substrate, and drying it. be done. The above-mentioned photosensitive layer includes a single layer type in which a charge generation material, a charge transport material and a binder resin are mixed, and a multilayer type in which a charge generation layer and a charge transport layer are laminated. It is applicable to both.

As the charge generating material, the general pyrrolopyrrole compound represented by N is used, and examples of the aryl group of R4 and R2 include phenyl, naphthyl, anthryl, phenanthryl, fluorenyl, 1-pyrenyl group, etc. Among them, phenyl group is preferred.

Examples of the aralkyl group include benzyl, phenylethyl, and naphthylmethyl groups.

Examples of the substituent in the aryl group or aralkyl group which may have a substituent include )\halogen atom, lower alkyl group having a halogen atom, cyano group, alkyl group,
Examples include substituents selected from the group consisting of alkoxy groups and dialkylamino groups.

Examples of the halogen atom include hydrogen, chlorine, bromine, and iodine, with chlorine or bromine being preferred.

In addition, examples of alkyl groups having a halogen atom include chloromethyl, dichloromethyl, trichloromethyl, 2-chloroethyl, 2.2-dichloroethyl, 2,2.2-)
'J Chloroethyl, trifluoromethyl group, etc. are exemplified.

Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, and stearyl groups with a carbon number of 1.
-18 alkyl groups are exemplified. Among the above alkyl groups, a straight chain or branched alkyl group having 1 to 12 carbon atoms, especially a straight chain or branched lower alkyl group having 1 to 6 carbon atoms, especially a straight chain or branched chain having 1 to 4 carbon atoms A lower alkyl group is preferred.

Alkoxy groups include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isofoxy, ter
Examples include t-butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, and stearyloxy groups. Among the above alkoxy groups,
Straight chain or branched chain alkoxy groups having 1 to 12 carbon atoms, particularly straight chain or branched lower alkoxy groups having 1 to 6 carbon atoms, particularly preferred are straight chain or branched lower alkoxy groups having 1 to 4 carbon atoms. .

Examples of dialkylamino groups include dialkylamino groups in which the alkyl moiety has 1 to 6 carbon atoms, such as dimethylamino, diethylamino, methylethylamino, dibutylamino, diisopropylamino, dibutylamino, diisobutylamino, di-tret-butylamino, diethylamino, and diacylamino groups. Examples include groups.

Examples of the heterocyclic group include thienyl, thianthrenyl, furyl, pyranyl, isobenzofuranyl, chromenyl, xanthenyl, phenoxathiinyl, pyrrolyl, imidazolyl, pyrazolyl, isothiazolyl, isoxasilyl, indidiridinyl, isoindolyl, indolyl, imidazolyl, brinyl, Pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, quinalinyl, isoquinolyl, quinolyl, phthalazinyl, naphthyridinyl, quinoxalinyl,
Quinazolinyl, cinnolinyl, pteridinyl, carbazolyl, carbolinyl, phenoxazinyl, acridinyl, berimidinyl, phenanthrolinyl, phthalazinyl,
Phenarsazinyl, phenothiazinyl, furazanyl, phenoxazinyl, isochromanyl, chromanyl, pyrrolidinyl, pyrrolinyl, imidazolidinyl, imidazolinyl, pyrazolidinyl, pyrazolinyl, piperidyl, piperidino, piperazinyl, indolinyl, isoindolinyl, quinuclidinyl, phorforinyl, phorphorino group, or a compound having the above heterocyclic group Examples include fused heterocyclic groups of fused heterocyclic compounds obtained by ortho- or helical condensation of and an aryl compound.

In addition, in the pyrrolopyrrole compound represented by the above general formula CI), the alkyl groups of R3 and R4 are:
Examples include lower alkyl groups having 1 to 6 carbon atoms as the substituents R and R2.

Among the above alkyl groups, alkyl groups having 1 to 4 carbon atoms are preferred.

In addition, as the aryl group which may have a substituent,
A phenyl group which may have a substituent on the phenyl ring is preferred, and the substituent for the phenyl group includes a halogen atom, a lower alkyl group having a halogen atom, an alkyl group, an alkoxy group, an alkylthio group, and a nitro group. Preferred are substituents selected from the group consisting of: Examples of the above-mentioned halogen atom, lower alkyl group having a halogen atom, alkyl group, and alkoxy group include the same substituents as the above-mentioned substituents R1 and R2. Alkylthio groups include methylthio, ethylthio, propylthio, isopropylthio,
Butylthio, isobutylthio, tert-butylthio,
Examples include pentylthio, hexylthio, heptylthio, octylthio, nonylthio, decylthio, undecylthio, dodecylthio, and stearylthio groups. Among the above alkylthio groups, straight-chain or branched lower alkylthio groups having 1 to 6 carbon atoms are preferred, particularly preferred are straight-chain or branched lower alkylthio groups having 1 to 4 carbon atoms.

In addition, it is particularly preferable that the above-mentioned substituents R3 and R4 are hydrogen atoms.

Among the above pyrrolopyrrole compounds, 1,4-dithioke 1--3. 6-diphenylvirolo(3,4-c)pyrrole, 114-dithioketo-3
, 6-di(4-tolyl)pyrrolo(3,4-c)pyrrole, 1,4-dithioketo-3,6-di(4-ethylphenyl)pyrrolo[3°4-c]pyrrole, 1,4- Dithioketo-3,6-cy(4-7” lobylphenyl)pyrrolo[3
,4-C]virol, 1,4-dithioketo-3,6-di(4-isopropylphenyl)pyrroloC3,4C]virol, 1,4-dithioketo-3,6-di(4-butylphenyl)pyrrolo( 3,4-cl pyrrole, 1,4-dithioketo-3,6-di(4isobutylphenyl)pyrrolo(
3,4-c]virol, 1,4-dithioketo-3,6-
Di(4-term-butylphenyl)pyrrolo(3,4-
c) Pyrrole, 1,4-dithioketo-3,6-di(4pentylphenyl)pyrrolo(3,4-c)pyrrole, 1,
4-dithioketo-3,6-di(4-hexylphenyl)
Pyrrolo(3,4-c)pyrrole, 1,4-dithioketo-
3,6-di(3,5-dimethylphenyl)pyrrolo(3,
4-c) Pyrrole, 1,4-dithioketo-3,6-di(
3,4,5-trimethylphenyl)pyrrolo(3,4-c
) pyrrole, 1,4-dithioketo-3,6-di(4-methoxyphenyl)pyrrolo(3,4-c)pyrrole, 1.
4-dithioketo-3,6-di(4-ethoxyphenyl)
Pyrrolo(3,4-c)pyrrole, 14-dithioketo-3
,6-di(4-propoxyphenyl)pyrroloC3,4-
c) Pyrrole, 1,4-dithioketo-3,6-di(4-
Impropoxyphenyl)pyrrolo(3,4-c)pyrrole, 14-dithioketo-3,6-di(4-butoxyphenyl)pyrroloC3,4-C)pyrrole, 1.4dithioketo-3,6-di(4 -isobutoxyphenyl)pyrrolo(
3,4-c) pyrrole, 1,4 dithioketo-3,6-di(4-tert-butoxyphenyl)pyrrolo(3,4-
c) Virol, 1°4-dithioketo-3,6-di(4-
Pentyloxyphenyl)pyrrolo(3,4-C)virol, 14-dithioketo-3,6-di(4-hexyloxyphenyl)pyrrolo(3,4-c)virol, 1°4-
dithioketo-3,6-di(3,5-dimethoxyphenyl)pyrrolo(3,4-c)virol, 14-dithioketo-
3,6-di(3,4,5-trimethoxyphenyl)pyrrolo(3,4-c)virol, 1,4-dithioketo-36
-dibenzylpyrrolo(3,4-cl pyrrol, ■, 4-
Dithioke 1--3,6-dinaphthylvirolo[3,4-c
) virol, 1,4-dithioketo-3,6-di(4cyanophenyl)pyrrolo(3,4-c)virol, 1,4-
Dithioketo-3,6-di(4-chlorophenyl)pyrrolo(3,4-C)virol, 1,4-cythioketo-3,6
-di(2-bromophenyl)pyrrolo(3,4-c)virol, 1,4-dithioketo-3,6-di(4-trifluoromethylphenyl)pyrrolo(3,4-c)virol,
1゜4-dithioketo-3,6-di(4-dimethylaminophenyl)pyrrolo(3,4-c:]virol, 114-
Dithioketo-3,6-di(4-diethylaminophenyl)pyrrolo(3,4-C)virol, N.

N''-dimethyl-1,4-dithioketo-3,6 diphenylvirol (3,4-c)virol, N.

N.-dimethyl-1,4-dithioketo-3,6-dydolylvirol (3,4-c)virol, N,N.

-dimethyl-1,4-dithioketo-3,6-di(4-ethylphenyl)pyrrolo(3,4-c)virol, N,
N=-dimethyl-1,4-dithioketo-3,6-di(4
-isopropylphenyl)pyrrolo(3,4-c)virol, N, N-dimethyl-1,4-dithioketo-3
,6-di(4-tert-butylphenyl)pyrrolo(3
,4-c) Virol, N, N=-dimethyl-1,4
-dithioketo-3,6-di(3,4,5-trimethylphenyl)pyrrolo(3,4-c)virol, N,N-dimethyl-1,4-dithioketo-3,6-di(4-methoxyphenyl) ) pyrrolo(3,4-c)virol, N, N
'-Dimethyl-1,4-dithioketo-3,6-di(4-
ethoxyphenyl)pyrrolo(3,4-c)virol, N
, N-dimethyl 1,4-dithioketo-3,6-di(4-isopropoxyphenyl)pyrrolo(3,4-c)
Pyrrole, N, N"-dimethyl-1,4-dithioketo-3゜6-di(4-tert-butoxyphenyl)pyrrolo(3,4-c]pyrrole, N, N-dimethyl-
1,4-dithioketo-3,6-di(3,4,5trimethoxyphenyl)pyrroloC3,4-c)virol, N,
N=-dimethyl-1,4-dithioketo-3,6-di(
3-pyrrolyl)pyrrolo[3゜4-〇]virol, 1.4
-dithioketo-3,6-di(3-pyrrolyl)pyrrolo(3
, 4-c) virol, 1,4-dithioketo-3,6-di(4-oxacylyl)pyrrolo(3,4-c) virol,
1゜4-dithioketo-3,6-di(4-thiazolyl)pyrrolo[3,4-c)virol, 1,4-dithioketo-3
, 6-diimidazolylvirolo(3,4-C]pyrrole,
1,4-dithioketo-3,6-di(2-imidazolyl)
Pyrrolo(3,4-c)virol, 1,4-dithioketo-
3,6-di(4-imidazolyl)pyrrolo(3,4-c)
Birol, ■.

4-dithioketo-3,6-di(4-pyridyl)pyrrolo(
3,4-c) Virol, 1,4-dithioketo-3,6-
di(2-pyrimidyl)pyrrolo[3°4-C]virol,
1,4-dithioketo-3,6-dibiperidinopyrrolo(3
, 4-c) virol, 1,4-dithioketo-3,6-di(4-piperidinyl)pyrrolo(3,4-c) virol,
1.4-dithioketo-3,6-dimorpholinovirolo[3
゜4-c] virol, 1,4-dithioketo-3,6-di(2-quinolyl)pyrrolo(3,4-c) virol, 1.
4-dithioketo-3,6-di(3-benzo(b)thiophenyl)pyrrolo(3,4-c)virol, N, N.
-dimethyl-1,4-dithioketo-3,6-di(4-imidazolyl)pyrrolo(3,4-c)virol, N,
N = -dimethyl-1,4-dithioketo-3,6-dimorpholinopyrrolo[3,4-c]pyrrole, N, N.
-dimethyl-1,4-dithioketo-3,6-di(4-
Examples include pyrrolo(pyridyl)pyrrolo(3,4-cl)virol, and 1,4-dithioketo-3,6-diphenylpyrrolo(3,4-c)virol is particularly preferred.

The pyrrolopyrrole compounds represented by formula (1) above may be used alone or in combination of two or more.

Furthermore, the pyrrolopyrrole compound represented by the above general formula (1) may be used in combination with various charge generating materials within the range that does not impair the photosensitivity properties, etc. Examples of the charge generating material include selenium, selenium-tellurium, amorphous silicon, biryllium salts, azo compounds, disazo compounds, phthalocyanine compounds, anthanthrone compounds, perylene compounds, indigo compounds, and triphenylmethane compounds. compounds, thren compounds, toluidine compounds, birapurin compounds, quinacridone compounds, and the like. One or more types of the above charge generating materials may be used.

Note that the charge generating material described above can be selected as appropriate.

As the charge transport material, the above-mentioned general 2CII) CI [[]
A hydrazone compound represented by is used. Examples of the alkyl groups for R5 and R6 in the general formula [■] include the same substituents as the substituents R3 and R4. Further, as the aralkyl group of the general formula %, the substituents R and R2
Examples of substituents similar to R5, R6R, and R1
Examples of the aryl group which may have a substituent include the same substituents as the above substituents R3 and R4.

The hydrazone compound represented by the general formula [■] or [III) is combined with the pyrrolopyrrole compound represented by the general formula (1) to form a photosensitive layer,
A photoreceptor with high sensitivity and low residual potential can be obtained, but if necessary, it may be used in combination with other charge transport materials as long as the charging characteristics, photosensitivity characteristics, etc. are not impaired. Examples of the other charge transport materials include tetracyanoethylene, 2,4.
Fluorenone compounds such as 7-dolinitro-9-fluorenone, nitrated compounds such as 2,4.8-)linitrothioxanthone and dinitroanthracene, succinic anhydride,
Maleic anhydride, dibromomaleic anhydride, oxadiazole compounds such as 2,5-di(4-dimethylaminophenyl)-1,3,4-oxadiazole, 9-(4-
Styryl compounds such as diethylaminostyryl)anthracene, carbazole compounds such as polyvinylcarbazole, pyrazoline compounds such as 1-phenyl-3-(P-diethylaminophenyl)pyrazoline, 4°4'
4”-)lis(4-diethylaminophenyl)triphenylamine, 4,4′-bis(Nphenyl-N-
(3-methylphenyl)aminocodiphenyl, 4,4゛-bis(N,N-di(4-methylphenyl)amino)-
Amine derivatives such as 3,3--dimethylphenyl, 4-
(N, N-diethylamino)benzaldehyde N,
Nitrogen-containing cyclic compounds such as hydrazone compounds such as N-diphenylhydrazone, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, triazole compounds, Examples include fused polycyclic compounds. These charge transport materials are
Used singly or in combination of two or more.

Various binder resins can be used, such as styrene polymers, acrylic polymers, styrene-acrylic polymers, olefin polymers such as ethylene-vinyl acetate copolymers, polyvinyl chloride, and vinyl chloride. Vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, epoxy resin, polycarbonate such as poly(4,4'-cyclohexylidene diphenyl) carbonate, polyarylate, polysulfone, diallyl phthalate, silicone resin, ketone resin, Various polymers can be used, such as polyvinyl butyral resin, polyether resin, phenol resin, and photocurable resin such as epoxy acrylate.

In a single-layer type electrophotographic photoreceptor, the amount of the charge generating material is 2 to 20 parts by weight, especially 3 parts by weight, per 100 parts by weight of the binder resin.
~15 parts by weight of the charge transport material, suitably 40 to 200 parts by weight, especially 50 to 150 parts by weight. If the amount of the charge-generating material and the charge-transporting material is less than the above-mentioned amount, not only the sensitivity of the photoreceptor will not be sufficient, but also the residual potential will become large. Further, if the amount exceeds the above range, the abrasion resistance of the photoreceptor will not be sufficient. In addition, the thickness of the single-layer type photosensitive layer is 10 to 50 μm.
In particular, it is preferably about 15 to 25 μm.

In the laminated electrophotographic photoreceptor, the charge generation material and the binder resin constituting the charge generation layer can be used in various ratios; It is preferably used in a proportion of 700 parts by weight, particularly 20 to 500 parts by weight. If the amount of the charge generating material is less than 10 parts by weight, the charge generating ability will be low, and if it exceeds 700 parts by weight, there will be problems such as poor adhesion. Further, the charge generation layer may have an appropriate thickness, but may have a thickness of 0.05 to 5.
It is preferable that the thickness be formed to be approximately 0.1 to 3 μm.

The charge transport material and the binder resin constituting the charge transport layer can be used in various ratios, but in order to easily transport the charges generated in the charge generation layer by light irradiation,
10 to 5 parts of charge transport material per 100 parts by weight of binder resin
It is preferably used in a proportion of 0.00 parts by weight, particularly 25 to 200 parts by weight.

If the amount of the charge transport material is less than 10 parts by weight, the charge transport ability will not be sufficient, and if it exceeds 500 parts by weight, the mechanical strength etc. of the charge transport layer will decrease. In addition, the charge transport layer has a content of 5 to 10
It is preferably formed to have a thickness of about 0 μm, particularly about 10 to 30 μm.

The conductive substrate may be in the form of a conductive sheet or drum, and may be made of various conductive materials, such as alumite-treated or untreated aluminum, aluminum alloy, copper. , tin, platinum, gold, silver, vanadium, molybdenum, chromium, cadmium,
Examples include simple metals such as titanium, nickel, palladium, indium, stainless steel, and brass, as well as plastic materials and glass on which layers of the above metals, indium oxide, tin oxide, etc. are formed by means such as vapor deposition. Preferably, the material is anodized using a sulfuric acid alumite method and sealed with nickel acetate.

Further, the conductive substrate may be surface-treated with a silane coupling agent, a titanium coupling agent, or the like to improve adhesion to the photosensitive layer, if necessary.

In addition, when preparing the coating liquid for the photosensitive layer consisting of each component such as the charge transport material, charge generation material, and binder resin,
An appropriate organic solvent is used depending on the type of binder resin used, and examples of the organic solvent include methanol,
Alcohols such as ethanol, propatool, isopropanol, butanol, n-hexane, octane,
Aliphatic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as benzene, toluene, xylene, dichloromethane,
Halogenated hydrocarbons such as dichloroethane and chlorobenzene, ethers such as tetrahydrofuran, 1,4-dioxane, ethylene glycol dimethyl ether, and ethylene glycol diethyl ether, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and esters such as ethyl acetate and methyl acetate. Various solvents such as
They may be used singly or in combination of two or more. In addition, when preparing the coating solution for the photosensitive layer, in order to improve dispersibility, coating properties, etc., leveling agents such as surfactants and silicone oils, or conventionally known leveling agents such as terphenyl, halonaphthoquinones, and acenaphthylene are used. Various additives such as sensitizers may be used in combination.

As the silicone oil, polydimethylsiloxane is preferable.

The above-mentioned coating liquid for the photosensitive layer can be prepared by conventional mixing and dispersion methods.
For example, it can be prepared using a paint shaker, mixer ball mill, sand mill, attritor, ultrasonic disperser, etc. When applying the obtained coating solution for the photosensitive layer, a conventional coating method such as a dip coating method can be used. Coating, spray coating, spin coating, roller coating, blade coating, curtain coating, bar coating, etc. are employed.

(Example) Hereinafter, the present invention will be explained in more detail based on examples.

An electrophotographic photoreceptor was prepared in the following manner using the following pyrrolopyrrole compound as a charge generating material and the following hydrazone compound as a charge transporting material.

Pyrrolopyrrole 7, Mu A: 1,4-dithioketo-3,6-diphenylvirolo C
3,4-C) Virol B: 1,4-dithioketo-3,6-di(4-tolyl)pyrrolo(3,4-C) Virol C: 1,4-dithioketo-3,6-di(4- methoxyphenyl)pyrrolo(3,4-C)virol D: 1,4-dithioketo-3,6-dinitylvirolo(3
,4-C) Virol E,N,N=-diethyl-1,4-dithioketodite
rt-Butylpyrrolo(3,4-C)virol F: 1,4-dithioketo-3,6-distearylpyrrolo(3,4-C)virolhycine, human [Preparation of laminated electrophotographic photoreceptor] Implementation Examples 1 to 9 10 parts by weight of the above pyrrolopyrrole compound shown in Table 1 as a charge-generating material, 10 parts by weight of vinyl chloride-vinyl acetate copolymer (manufactured by Tanezu Kagaku Kogyo Co., Ltd., trade name: Meiko Suretsuku C) and a predetermined amount. A charge generation layer coating solution made of tetrahydrofuran of was formed.

Next, the above hydrazone compound 1.0 shown in Table 1
10 parts by weight of bisphenol Z type polycarbonate (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name PCZ) and a predetermined amount of toluene were mixed and dissolved to prepare a coating solution for the charge transport layer, and the mixture was coated on the charge generation layer. By heating and drying, a charge transport layer having a thickness of 20 μm was formed, and an electrophotographic photoreceptor having a laminated photosensitive layer was produced.

Comparative Examples 1 to 2 An electrophotographic photoreceptor having a laminated photosensitive layer was produced in the same manner as in the above example, except that a compound represented by L in the following formula was used in place of the hydrazone compound of Example 1. was created.

Comparative Examples 3 to 4 An electrophotographic photoreceptor having a laminated photosensitive layer was produced in the same manner as in the above example, except that compounds represented by M and N below were used in place of the pyrrolopyrrole compound of Example 1. was created.

M: 4.10-dibromo-dibenzo (def, mno)
Chrysene-6,12-dione N: N,N-di(3,5-dimethylphenyl)perylene-3,4,9,10-tetracarboxydiimide [Evaluation of electrophotographic photoreceptor] Drum sensitivity tester (Diente・Using (manufactured by Tsuku Corporation),
A flowing current was applied to the electrophotographic photoreceptor G obtained in each of the above Examples to charge the surface potential V, p (V) to approximately -700V.

After that, a tungsten lamp was used to emit 831ux light at 60°C.
Irradiated for m5ec.

The time required for the surface potential Vsp (V) to become 1/2 was determined, and the half-reduced exposure amount El/2 (luxsec) was calculated.

Furthermore, the potential 0.4 seconds after the start of exposure is the residual potential V, p
(V).

(The following is a blank space) Table 1 As is clear from Table 1, the electrophotographic photoreceptor of the present invention (Examples 1 to 9) has a pyrrolopyrrole compound containing a compound other than that represented by the general formula (IIl, (1)). An electrophotographic photoreceptor in which a hydrazone compound is combined (Comparative Examples 1 to 2), and a pigment other than a pyrrolopyrrole compound has the general formula [m
), CDI) Compared to the electrophotographic photoreceptors (Comparative Examples 3 to 4) in which hydrazone compounds represented by the following formulas are combined, it can be seen that all of them have good sensitivity and excellent electrophotographic properties with low residual potential. .

[Preparation of single-layer electrophotographic photoreceptor]

Examples 10 to 13 8 parts by weight of the pyrrolopyrrole compound shown in Table 2 as a charge-generating material, 100 parts by weight of the hydrazone compound shown in Table 2 as a charge-transporting material, bisphenol Z-type polycarbonate (Mitsubishi Gas Chemical Co., Ltd.) A paint shaker was charged with 100 parts by weight of PCZ (trade name: PCZ) and a predetermined amount of tetrahydrofuran, and the mixture was mixed and dispersed for 3 hours to prepare a coating solution for a single-layer electrophotographic photosensitive layer. The above coating solution was applied onto an aluminum sheet, heat treated at 100°C for 30 minutes,
An electrophotographic photoreceptor having a single-layer photosensitive layer with a thickness of 18 μm was produced.

Comparative Example 5 An electrophotographic photoreceptor having a single-layer type photosensitive layer was produced in the same manner as in the above Example, except that the compound represented by the above formula was used in place of the hydrazone compound of Example 10.

Comparative Example 6 An electrophotographic photoreceptor having a single-layer type photosensitive layer was produced in the same manner as in the above Example, except that the compound represented by the formula M was used in place of the pyrrolopyrrole compound in Example 10. .

[Evaluation of electrophotographic photoreceptor]

Using a drum sensitivity tester (manufactured by Zientic Co., Ltd.), a flowing current was applied to the electrophotographic photoreceptor obtained in each of the above examples to charge it so that the surface potential V, p (V) was around ±700V. I let it happen.

After that, a tungsten lamp was used to emit light of 831uχ at 60°C.
Irradiated for ms e c.

Determine the time until the above surface potential v-p(v) becomes 1/2, and calculate the halving exposure amount E l / 2 (l u x se
c) was calculated. Further, the potential 0.4 seconds after the start of exposure was defined as residual potential V, (V).

Table 2 As is clear from Table 2, the electrophotographic photoreceptors of the present invention (Examples 10 to 13) had the general formula CII), CI!, in the pyrrolopyrrole compound. Electrophotographic photoreceptor combined with a hydrazone compound other than those represented by I) (Comparative Example 5)
), and an electrophotographic photoreceptor (Comparative Example 6) in which a hydrazone compound represented by the general formula [n] or (III) is combined with a pigment other than a pyrrolopyrrole compound (Comparative Example 6), both showed good sensitivity. It can be seen that it has excellent electrophotographic properties with low residual potential.

Comparative Example 7 A single-layer photosensitive film was produced in the same manner as in the above example except that N-ethyl-3-carbazolylaldehyde-N,N-diphenylhydrazine was used in place of the hydrazone compound in Example 10. An electrophotographic photoreceptor having layers was produced.

Comparative Example 8 In place of the hydrazone compound of Example 1, N-ethyl-3
-Carbazolylaldehyde-N, An electrophotographic photoreceptor having a laminated photosensitive layer was produced in the same manner as in the above example except that N,N diphenylhydrazone was used.

[Evaluation of photostability] Using a fluorescent lamp, 5001 ux of light was applied to the surface of the electrophotographic photoreceptor obtained in each of the above Examples and Comparative Examples 7 and 8.
Exposure was made for 0 minutes. Then, the electrophotographic photoreceptor after exposure is
After being left at room temperature in a dark place for 2 hours, it was loaded into a copying machine (manufactured by Sanda Kogyo Co., Ltd., DC-3255 modified machine) to obtain a copy image.

With the electrophotographic photoreceptors obtained in each example, good copied images were obtained, but when the electrophotographic photoreceptors obtained in Comparative Examples 7 and 8 were used, unclear copied images with white spots were obtained. Obtained.

(Effects of the Invention) As described above, according to the electrophotographic photoreceptor of the present invention, the photosensitive layer contains a pyrrolopyrrole compound represented by the above general formula [1], and the above general formula (I[) and/or Since it contains the hydrazone compound represented by the general formula (I[]), it exhibits the unique effects of excellent photostability, good sensitivity, and low residual potential.

Claims (1)

[Claims] (1) In a photoreceptor in which a photosensitive layer is formed on a conductive substrate, the photosensitive layer contains a pyrrolopyrrole compound represented by the following general formula [I] and a hydrazone represented by the following general formula [II]. 1. An electrophotographic photoreceptor comprising a hydrazone compound and/or a hydrazone compound represented by formula [III]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] (In the formula, R_1 and R_2 are the same or different,
It represents an aryl group, an aralkyl group, or a heterocyclic group that may have a substituent, and R_3 and R_4 are the same or different and represent a hydrogen atom, an alkyl group, or an aryl group that may have a substituent. ) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [II] (In the formula, R_5 and R_6 are the same or different,
It represents an alkyl group, an aralkyl group, or an aryl group that may have a substituent, and R_7 represents a prenyl group, an isoamyl group, or a benzyl group. ) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼
[III] (wherein R_8 and R_9 are the same or different,
Indicates an aralkyl group and an aryl group which may have a substituent. )