JPH01271755A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve fluctuation of light part potential and dark part potential of an electrophotographic sensitive body when repetitive charge and exposure are executed, by incorporating a specified diamino benzanthrene compd. into a photosensitive layer. CONSTITUTION:A diamino benzanthrene compd. expressed by the formula I is incorporated into a photosensitive layer of an electroconductive base. In the formula I, each R1-R4 is a (substituted) alkyl group, aryl group, or aralkyl group; each R5 and R6 is a halogen atom, alkyl group, alkoxy group, etc.; as a preferred specific example, a diamino benzanthrene compd. expressed by the formula I is used as a charge transfer material of an electrophotographic sensitive body having a photosensitive layer function-separated into a charge generating layer and a charge transfer layer. By this constitution, fluctuation of light part potential and dark part potential of an electrophotographic sensitive body in a stage of forming continuous picture image by carrying out repetitive charge and exposure, are kept at small degree.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to electrophotographic photoreceptors, and more particularly to electrophotographic photoreceptors containing low molecular weight organic photoconductors that provide improved electrophotographic properties.

[Prior Art] Conventionally, various organic photoconductive polymers including polyvinylcarbazole have been proposed as photoconductive materials for use in electrophotographic photoreceptors. Although it is superior in terms of film formability and light weight, it has been difficult to put it into practical use until now because sufficient film formability has not yet been obtained, and sensitivity, durability, and This is because they are inferior to inorganic photoconductive materials in terms of stability against environmental changes.

Also, hydrazone compounds disclosed in U.S. Pat. No. 4,150,987, etc., doarylpyrazoline compounds disclosed in U.S. Pat.
Low-molecular organic photoconductors such as 9-styrylanthracene compounds described in JP-A-94828 and JP-A-51-94829 have been proposed. These low-molecular-weight organic photoconductors have been able to overcome the film-forming problems that had been a problem in the field of organic photoconductive polymers by appropriately selecting the binder used, but the sensitivity It cannot be said that it is sufficient in this respect.

For this reason, in recent years, a laminated structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer has been proposed. Electrophotographic photoreceptors using this laminated structure as a photosensitive layer can now be improved in terms of sensitivity to visible light, charge retention, surface strength, and the like.

Such an electrophotographic photoreceptor is disclosed in, for example, US Pat. No. 383
This method is disclosed in Japanese Patent Publication No. 7851, Japanese Patent Publication No. 3871882, Japanese Patent Publication No. 55655/1983, and the like.

However, electrophotographic photoreceptors that use conventional low-molecular organic photoconductors in the charge transport layer do not necessarily have sufficient sensitivity and characteristics, and when repeatedly charged and exposed, the bright area potential and dark area potential change. There are areas that need improvement.

[Problems to be Solved by the Invention] An object of the present invention is to provide an electrophotographic photoreceptor that eliminates the above-mentioned drawbacks or disadvantages, to provide a novel organic photoconductor, and to provide a charge generation layer and a charge transport layer. The object of the present invention is to provide a novel charge transport material in a laminated photosensitive layer with functionally separated functions.

[Means for Solving the Problems, Effects] The present invention provides an electrophotographic photoreceptor in which a photosensitive layer is laminated on a conductive support, wherein the photosensitive layer contains a diaminobenzanthrene compound represented by the following general formula (1). It consists of an electrophotographic photoreceptor characterized by:

In the Rp formula, R,, R2, R'3 and R4 represent an alkyl group, an aryl group or an aralkyl group which may have a substituent, and may be the same or different, and R5 and R
6 represents a halogen atom, an alkyl group, an alkoxy group, a nitro group, or a cyano group, and may be the same or different.

Specifically, R1-R4 include alkyl groups such as methyl, ethyl, propyl, and butyl, aryl groups such as phenyl, diphenyl, naphthyl, and anthryl, and aralkyl groups such as benzyl, phenethyl, and naphthylmethyl; , Substituents for the above groups include halogen atoms such as fluorine atom, chlorine atom, iodine atom, and bromine atom, alkyl groups such as methyl, ethyl, propyl, isopropyl, and butyl, and alkoxy groups such as methoxy, ethoxy, propoxy, and phenoxy. , nitro group, cyano group, dimethylamino, dibenzylamino, diphenylamino,
Examples include substituted amino groups such as morpholino, piperidino, and pyrrolidino.

R5, Re is a halogen atom such as a fluorine atom, a chlorine atom, an iodine atom, a bromine atom, methyl, ethyl,
Alkyl groups such as propyl, isopropyl, butyl,
Examples include alkoxy groups such as methoxy, ethoxy, propoxy, and phenoxy, nitro groups, and cyano groups.

Representative examples of the diaminobenzanthrene compound represented by the general formula (1) are listed below.

Compound Example (1) Compound Example (2) Compound Example (3) Compound Example (4) Compound Example (5) Compound Example (6) Compound Example (7) Compound Example (8) Compound Example (9) Compound Example (10) Compound Example (11) Compound Example (12) Compound Example (13) Compound Example (15) Compound Example (16) Compound Example (17) Compound Example (18) Compound Example (19) Compound Example (20) Compound Example (21) Compound Example (22) Compound Example (23) Compound Example (24) Compound Example (25) Compound Example (26) Compound Example (27) Compound Example (28) Compound Example (29) Compound Example (30) Compound Example (32) Compound Example (33) ρN Compound Example (34) Compound Example (35) Next, a general method for synthesizing the diaminobenzanthrene compound represented by the general formula (1) will be described.

When R1-R4 are the same, benzanthrene is dinitrated with nitric acid, reduced with Fe/HCl or hydrazine, and then reacted with R(1-4)I/NaH to obtain the desired product.

When R1-R4 are different, one equivalent of nitric acid is used to convert the compound to 10-nitro, and the compound represented by general formula (2) is reduced in the same manner as above, then one side of the amino acid is acetylated with acetic anhydride, and R3I is reacted. After that, remove the acetyl group with a base or acid, react R4I in the same way, and then
Upon nitration, a compound represented by general formula (3) can be obtained.

In a preferred embodiment of the present invention, a diaminobenzanthrene compound represented by the general formula (1) is used as the charge transport material of an electrophotographic photoreceptor in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer.

The charge transport layer in the present invention is preferably formed by applying a solution of the diaminobenzanthrene compound represented by the general formula (1) and a binder dissolved in a suitable solvent and drying the solution.

Examples of the binder used here include polyarylate,
Polysulfone, polyamide, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenolic resin, epoxy resin, polyester, alkyd resin, polycarbonate, polyurethane or copolymer, side light styrene-bitadiene copolymer, styrene -Acrylonitrile copolymer, styrene-maleic copolymer, etc. can be mentioned. In addition to such insulating polymers, organic photoconductive polymers such as polyvinyl carboxylate, polyvinylanthracene, and polyvinylpyrene can also be used.

The blending ratio of this binder and the specific charge transport substance is:
Preferably, the amount of the charge transport material is 10 to 500 parts by weight per 100 parts by weight of the binder.

The charge transport layer is electrically connected to the charge generation layer below and has the function of receiving charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. ing. At this time, this charge transport layer may be laminated on or under the charge generation layer. However, it is desirable that the charge transport layer is laminated on the charge generation layer.

Since this charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary. −
5 to 40 microns within the shell, but the preferred range is 1
It is 0 to 30 microns.

The organic solvent used to form such a charge transport layer varies depending on the type of binder used, and is preferably selected from those that do not dissolve the charge generation layer or underlying subbing layer.

Specific organic solvents include methanol, ethanol,
Alcohols such as isopropanol, ketones such as acetone, methyl ethyl ketone, cyclohexanone, N
, amides such as N-dimethylformamide and N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether;
Esters such as methyl acetate and ethyl acetate, aliphatic halogenated hydrocarbons such as methylene chloride, dichloroethylene, carbon tetrachloride, trichlorethylene, or benzene,
Aromatics such as toluene, xylene, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating methods include dip coating, spray coating, spinner coating, bead coating,
This can be carried out using a coating method such as a Mayer coating method, a blade coating method, a roller coating method, or a curtain coating method. For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying: -30 to 200°C inside the shell
It is preferable to carry out the process at a temperature of 5 minutes to 2 hours, either stationary or under ventilation.

The charge transport layer in the present invention may contain various additives. For example, plasticizers such as diphenyl, m-terphenyl, dibutyl phthalate, silicone oil, grafted silicone polymers, surface lubricants such as various fluorocarbons, potential stabilizers such as cyanohinyl compounds, carbazole derivatives, etc. -Carotene, Ni complex, 1,4-diazabicyclo[2,2,2
] Examples include anti-thickening agents such as octane.

The charge generation layer in the present invention includes fLR charge generation substances such as selenium, selenium-tellurium, and amorphous silicone, cationic dyes such as biryllium dyes, thiapyrylium dyes, asthrenium dyes, thiacyanine dyes, and quinocyanine dyes, and scuparium salts. selected from organic charge-generating substances such as polycyclic pigments such as dyes, phthalocyanine pigments, anthoanthrone pigments, dibenzpyrenequinone pigments, and pyranthrone pigments, indigo pigments, quinacridone pigments, and azo pigments. These materials can be used alone or in combination as a vapor deposited layer or a coating layer.

Among the above-mentioned charge-generating substances, there are a wide variety of azo pigments in particular, and typical structural examples of particularly effective azo pigments will be described below.

The general formula of the azo pigment is shown below, with the central skeleton being A and the coupler portion being Cp, where n is 1 or 2. Specific examples are given below.

A (N=N-Op) n Specific examples of A include (R: hydrogen atom, chlorine atom, methoxy group) (R: hydrogen atom, cyano group) (R: hydrogen atom, cyan group) (X: oxygen Atom, sulfur atom R: hydrogen atom, methyl group, chlorine atom) (X: oxygen atom, sulfur atom R1, R2: hydrogen atom, methyl group, chlorine atom) (R1, R2: hydrogen atom, methyl group, chlorine atom, etc. R
3: Hydrogen atom, methyl group, (X: oxygen atom, sulfur atom) (x: oxygen atom, sulfur atom) (X: oxygen atom, sulfur atom) (R: hydrogen atom, methyl group) (X: =CH, Oxygen atom, sulfur atom, =SO)A-
14 Mutton Samana (X: oxygen atom, sulfur atom) 1y A-1,8+cH=N-N=cH-@-A-21 N(
X (R: hydrogen atom, methyl group) Specific examples of Cp include (R: hydrogen atom, halogen atom, alkoxy group, alkyl group, nitro group, etc. n: 1 or 2) (R: methyl group, ethyl group) , propyl group, etc.) [R: alkyl group, 9 (Rゝ: hydrogen atom R' atom, halogen atom, alkoxy group, alkyl group, nitro group, etc.)] O (R: alkyl group, aryl group, etc.) R1, R2: hydrogen atom, halogen atom, alkoxy group, alkyl group, nitro group, nil or 2), and the like.

The central skeleton A and the coupler Cp form a pigment serving as a charge-generating substance by appropriate combination.

The charge generation layer can be formed by dispersing the charge generation substance described above in a suitable binder and coating it on a support, or by forming a vapor deposited film using a vacuum evaporation device. .

The binder can be selected from a wide range of insulating resins and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene.

Preferably polyvinyl butyral, polyarylate (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinylpyridine, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol,
Examples include polyvinylpyrrolidone.

The resin contained in the charge generation layer is suitably 80% by weight or less, preferably 40% by weight or less.

Organic solvents used during coating include alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and amides such as N,N-dimethylformamide and N,N-dimethylacetamide. , sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, and aliphatics such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene. Halogenated hydrocarbons or aromatics such as benzene, toluene, xylene, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating methods include dip coating, spray coating, spinner coating, bead coating,
This can be carried out using a coating method such as a Mayer coating method, a blade coating method, a roller coating method, or a curtain coating method. For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying - 30-200'O inside the shell
It is preferable to carry out the process at a temperature of 5 minutes to 2 hours, either stationary or under ventilation.

The charge generation layer contains as much of the organic photoconductor as possible in order to obtain sufficient absorbance and contains a thin film layer, e.g. 5 microns or less, preferably o, o
It is desirable to form a thin film layer having a thickness of 1 to 1 mil.

This means that most of the incident light is absorbed by the charge generation layer, generating many charge carriers, and that the generated charge carriers are not deactivated by recombination or trapping, but are transferred to the charge transport layer. This is due to the need for injection.

A photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer is provided on a support having a conductive layer. The support having a conductive layer may be one in which the support itself is conductive, such as aluminum, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold or platinum. In addition, plastics (e.g., polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate) have a layer formed by vacuum evaporation of aluminum, aluminum alloy, indium oxide, tin oxide, indium oxide-tin oxide alloy, etc. , acrylic resin, polyfluoroethylene, etc.), conductive particles (e.g. aluminum powder, titanium oxide, tin oxide,
A support in which plastic or the above-mentioned conductive support is coated with zinc oxide, carbon black, silver particles, etc.) together with a suitable binder, a support in which plastic or paper is impregnated with conductive particles, or a conductive polymer. Plastic can be used.

A subbing layer having barrier and adhesive functions can also be provided between the conductive support and the photosensitive layer.

The undercoat layer is formed of casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin, aluminum oxide, etc. can.

The thickness of the subbing layer is 0.1 to 5 microns, preferably 0.5 microns.
~3 microns is suitable.

When using a photoreceptor in which a conductive support, a charge generation layer, and a charge transport layer are laminated in this order, the charge transport compound in the present invention has hole transport properties, so it is necessary to negatively charge the surface of the charge transport layer. When exposed to light after being charged, holes generated in the charge generation layer in the exposed area are injected into the charge transport layer, and then reach the surface and neutralize the negative charge, resulting in attenuation of the surface potential and the gap between the exposed area and the unexposed area. Electrostatic contrast occurs.

During development, it is necessary to use positively charged toner.

In another embodiment of the invention, the aforementioned disazo pigments or the disazo pigments described in U.S. Pat.
The photoconductivity of biryllium dyes, thiapyrylium dyes, selenapyrylium dyes, benzobyrylium dyes, benzothiapyryllium dyes, naphthopyryllium dyes, naphthothiapyrylium dyes, etc. disclosed in Specification No. 8, Specification 3586500, etc. Pigments and dyes can also be used as sensitizers.

In another specific example, a eutectic complex of a biryllium dye and an electrically insulating polymer having an alkylidene diarylene moiety as disclosed in US Pat. No. 3,684,502 and the like can be used as a sensitizer. This eutectic complex is, for example, 4-[4-bis(2-chloroethyl)aminophenyl]
-2,6-cyphenylthiapyrylium perchlorate and poly(4,4''-isopropylidene diphenylene carbonate) are mixed in a halogenated hydrocarbon solvent such as dichloromethane, chloroform, carbon tetrachloride, 1°1-dichloroethane, ■, 2-dichloroethane, 1, l, 2
- To! After dissolving in chloroethane, chlorobenzene, bromobenzene, 1,2-dichlorobenzene, etc., add a nonpolar solvent such as hexane, octane, decane,
A particulate eutectic complex is obtained by adding 2,2,4-trimethylbenzene, ligroin, etc.

The electrophotographic photoreceptor in this specific example includes styrene-butadiene copolymer, silicone resin, vinyl resin, vinylidene chloride-acrylonitrile copolymer, styrene-acrylonitrile copolymer, vinyl acetate-vinyl chloride copolymer, polyvinyl butyral, polymethyl methacrylate, poly- N-butyl methacrylate,
Polyesters, cellulose esters, etc. can be contained as a binder.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines but also in a wide range of electrophotographic application fields such as laser beam printers, CRT printers, and electrophotographic plate making systems.

The electrophotographic photoreceptor of the present invention has the advantage of high sensitivity and small fluctuations in bright area potential and dark area potential when repeatedly charged and exposed.

[Example] Example 1 5 g of a disazo pigment represented by the following structural formula was mixed with butyral resin (
butyralization degree 63 mol%) 2g scrohexanone l
A coating solution was prepared by dispersing the mixture in a sand mill together with a solution dissolved in oomJlj for 24 hours.

This coating solution was applied onto an aluminum sheet using a Meyer bar to a dry film thickness of 0.2 μm to form a charge generation layer.

Next, Log compound example (20) as a charge transport material and 10 g of polycarbonate (average molecular weight 20,000) were dissolved in 70 g of monochloropentene, and this solution was applied onto the charge generation layer using a Mayer Per. A charge transport layer having a dry thickness of 20 microns was formed to produce an electrophotographic photoreceptor.

The electrophotographic photoreceptor thus prepared was corona-charged at 5 KV in a static mode using an electrostatic copying paper tester Model-3P-428 manufactured by Kawaguchi Juiki ■, held in a dark place for 1 second, and then exposed to light at an illuminance of 20 lux. , the charging characteristics were investigated.

As for charging characteristics, the surface potential (Vo) and the exposure amount (E 1/2) required to attenuate the potential (vl) to 1/2 when dark decayed for 1 second were measured.

Furthermore, in order to measure the fluctuations in bright area potential and dark area potential during repeated use, we attached an electrophotographic photoreceptor fabricated on the wood side to the photosensitive drum cylinder of Canon's PPC Duplicator NP-3525. 5,000 copies were made with the same machine, and the fluctuations in bright area potential (VL) and dark area potential (VD) were measured at the initial stage and after 5,000 copies were made.

Nao, initial VD and vL are -700V and -200■ respectively.
It was set so that

In addition, for comparison, a similar electrophotographic photoreceptor was prepared using a compound (A) represented by the following structural formula in place of the above-mentioned compound example as a charge transport material, and measurements were carried out in the same manner.

Show the results.

Example 1 -700 -695 2.3 Comparative Example 1 -
690 -650 5.8V5
V Example I VD -700-690VL -20
0, -210 Comparative Example I VD -700-600VL -20
0-310 As is clear from the above results, it can be seen that when the charge transport compound specified in the present invention is used, it has good sensitivity and less potential fluctuation during durability.

Examples 2 to 15 In each of these Examples, in place of the charge transport compound example (20) used in Example 1, compound examples (1), (3), and (4) were used.
), (7), (8), (9), (11), (14), (
15), (16), (24), (28), (30), (
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the pigment having the structural formula shown below was used as the charge generating substance.

O The electrophotographic characteristics of each photoreceptor were measured in the same manner as in Example 1. Show the results.

2 (1) 700 690 2.03
(3) 700 685 2.54
(4) 690 680 2.35
(7) 700 685 2.86
(8) 700 695 1.97
(9) 690 680 2
．． 28 (11) 700 690
2.09 (14) 690 68
0 3.010 (15) 700
690 1.811 (16) 6
90 680 2.112 (24)
700 690 2.913 (28
) 690 680 2.814
(30) 690 680 3.215
(32) 700 69C12,7 first
After 5,000 pieces of sake Example 16 An ammonia aqueous solution of casein (11.2 g of casein, 1 g of 28% ammonia water, 22.2 m of water) was coated on an aluminum cylinder using the blade coating method, and the dry thickness was 1 micron. A subbing layer was formed.

Next, 5 g of a charge generating substance represented by the following structural formula, log of butyral resin (degree of butyralization: 63 mol %), and 200 g of cyclohexanone were dispersed for 48 hours using a ball mill disperser. This dispersion was applied onto the previously formed subbing layer by a blade coating method to form a charge generating layer with a dry film thickness of 0.15 microns.

Next, 10 g of Compound Example (18) and log of polymethyl methacrylate (average molecular weight 50,000) were dissolved in 70 g of monochlorobenzene, and the solution was coated on the previously formed charge generation layer by a blade coating method, with a dry film thickness of 19 A micron charge transport layer was formed. .

A corona discharge of 15 KV was applied to the electrophotographic photoreceptor thus prepared. The surface potential at this time was measured (initial potential Vo). Furthermore, the surface potential of this photoreceptor was measured after it was left in a dark place for 1 second.

Sensitivity is the exposure amount (El/2, microjoule/cm2) required to attenuate the potential v1 after dark decay to 1/2.
It was evaluated by measuring.

At this time, the light source was a gallium/aluminum/arsenic ternary semiconductor laser (output: 5 mw, oscillation wavelength: 780 nm).
m) was used. Show the results.

vo knee 700V vt knee 695VEl
/2: 2.4 microunits/cm2 Next, the photoreceptor was transferred to a laser beam printer (manufactured by Canon ■, LBP-CX), which is a reversal development type electrophotographic printer equipped with the same semiconductor laser. An actual image forming test was conducted by setting the photoreceptor in place of the CX photoreceptor.

The conditions were: surface potential knee 700 V after negative charging, surface potential knee 150 V after image exposure (fi light intensity 2.0 microdeg/cm2), transfer potential: +700 V, developer polarity:
Negative polarity, process speed = 50 mm/sec, development conditions (development bias) knee 450V, image exposure scan method: image scan, - exposure before next charging = 50 mm uX, S
The entire surface of the ec was exposed to red light and the image was formed by line scanning a laser beam in accordance with the character and image signals, and good prints were obtained for both the characters and the image. Furthermore, when a series of 3,000 images were printed, stable and good prints were obtained from the initial stage up to 3,000 sheets.

Example 17 3 g of 4-(4-dimethylaminophenyl)-2,6-siphenylthiapyrylium perchlorate and compound example (2
) and 5g of polyester (Polyester Adhesive 4
9000, manufactured by DuPont) toluene (50 parts by weight) -
Dioxane (50 parts by weight) was mixed with 100 ml of solution,
The mixture was dispersed for 6 hours using a ball mill disperser. This dispersion was applied onto an aluminum sheet using a Meyer bar so that the film thickness after drying was 15 microns.

The electrophotographic properties of the electrophotographic photoreceptor thus prepared were measured in the same manner as in Example 1. Show the results.

vo Knee 690V Vl Knee 680VEl
/2: 3.0 sentences uX, Sec First-1st period Vo Knee 690V VL Knee 200V Shadow i Kusara Hisatsuki V o: -670V V L:
-205V Example 18 3 g of 47-(4-dimethylaminophenyl)-2,6-cyphenylthiapyrylium perchlorate and poly(4,
4"-isopropylidene diphenylene carbonate) 3
After fully dissolving g in 200 mJL of dichloromethane,
100 mM toluene was added to precipitate the eutectic complex. After filtering this precipitate, dichloromethane was added to redissolve it, and then 100'mM of n-hexane was added to this solution to obtain a precipitate of a eutectic complex.

5 g of this eutectic complex was added to 95 ml of a methanol solution containing 2 g of polyvinyl butyral, and dispersed for 6 hours using a ball mill disperser. This dispersion was applied onto an aluminum plate having a casein layer using a Mayer bar to form a charge generation layer so that the film thickness after drying was 0.4 microns.

Next, a cover layer of a charge transport layer was formed in the same manner as in Example 1 except that Compound Example (19) was used on the charge generation layer.

The electrophotographic properties of the thus produced electrophotographic photoreceptor were measured in the same manner as in Example 1.

Show the results.

vo knee 700V VL knee 685Vel
/2:3. IMux, see -1 VD Knee 690V VL Knee 200V (Vn Knee 680V VL Knee 210V Example 1)
9 An ammonia aqueous solution of casein (described above) was applied on an aluminum plate using a Meyer bar to form a subbing layer with a dry film thickness of 1 micron. On top of this, the charge transport layer and charge generation layer of Example 1 were sequentially laminated, and an electrophotographic photoreceptor was prepared in the same manner as in Example 1 except for the layer structure, and the charging properties were the same as in Example 1. was measured. However, the charge was set to 10. Show the results.

vo: +700V Vl: +680VEl/2
:3.7uux, sec Example 20 Soluble nylon (6-66-610-12
A 5% methanol solution of (quaternary nylon copolymer) was applied to form a subbing layer having a dry thickness of 0.5 microns.

Next, 5 g of the pigment having the following structural formula was added to 95 g of tetrahydrofuran.
The mixture was dispersed in mu using a sand mill disperser for 200 hours.

Next, a solution prepared by dissolving 5 g of Compound Example (31) and 10 g of bisphenol Z type polycarbonate (viscosity average molecular weight 30,000) in 30 ml of monochlorobenzene was added to the dispersion prepared above, and the mixture was further dispersed for 2 hours using a sand mill. This dispersion was applied onto the previously formed subbing layer using a Mayer bar so that the film thickness after drying would be 20 microns, and then dried.

The electrophotographic properties of the electrophotographic photoreceptor thus prepared were measured in the same manner as in Example 1. Show the results.

vo knee 700V VT: -690
VEL/2:2. ! 1llux, see [Effects of the Invention] The electrophotographic photoreceptor containing the diaminobenzanthrene compound of the present invention has high sensitivity and durability with small fluctuations in bright area potential and dark area potential during continuous image formation by repeated charging exposure. There is an electrophotographic photoreceptor with excellent properties.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer laminated on a conductive support, characterized in that the photosensitive layer contains a diaminobenzanthrene compound represented by the following general formula (1). Photographic photoreceptor. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (1) In the formula, R_1, R_2, R_3, and R_4 represent an alkyl group, an aryl group, or an aralkyl group that may have a substituent, and they may be the same or different. Good luck, R_5
and R_6 represents a halogen atom, an alkyl group, an alkoxy group, a nitro group or a cyano group, and may be the same or different.