JPH0830896B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an electrophotographic photoreceptor, and more particularly, to an electrophotographic photoreceptor having a low molecular organic photoconductor that provides improved electrophotographic properties.

[Prior Art] Conventionally, various kinds of organic photoconductive polymers such as polyvinylcarbazole have been proposed as photoconductive materials used in electrophotographic photoreceptors.
Although it is superior to inorganic photoconductive materials in terms of film formability and lightness, it has been difficult to put it into practical use to date because sufficient film formability has not yet been obtained. This is because it is inferior to the inorganic photoconductive material in terms of sensitivity, durability and stability due to environmental changes.

Also, hydrazone compounds described in U.S. Pat.No. 4,150,987, triarylpyrazoline compounds described in U.S. Pat.No. 3,738,851, JP-A-51-94828, JP-A-51-94829 and the like. Low molecular weight organic photoconductors such as the described 9-styrylanthracene compounds have been proposed.

Such a low-molecular organic photoconductor, by appropriately selecting the binder to be used, it has become possible to eliminate the drawbacks of film formation that has been a problem in the field of organic photoconductive polymers, It is not enough in terms of sensitivity.

For these reasons, a laminated structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer has recently been proposed. The electrophotographic photoreceptor having this laminated structure as a photosensitive layer can be improved in terms of sensitivity to visible light, charge retention, surface strength, and the like.

Such an electrophotographic photoreceptor is disclosed, for example, in U.S. Pat. No. 3837851.
No. 3871882, and the like.

Further, in JP-A-58-199352, JP-A-61-245165, JP-A-62-964, etc., a hydrazone compound having a substituted amino group in the para position is described as a charge transporting substance. There is.

However, the sensitivity and characteristics are not always sufficient in the electrophotographic photosensitive member using the conventional low-molecular weight organic photoconductor for the charge transport layer, and when it is repeatedly charged and exposed after intense exposure irradiation. Has a point that the fluctuations in the light potential and the dark potential should be greatly improved.

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

[Means and Actions for Solving the Problems] The present invention is an electrophotographic photoreceptor in which a photosensitive layer is laminated on a conductive support, wherein the photosensitive layer contains a compound represented by the following general formula (I). And an electrophotographic photoreceptor.

In the formula, Ar represents an aryl group having a substituted amino group at least in the ortho position, R ₁ and R ₂ are the same or different, and may have an alkyl group which may have a substituent, or a substituent which may have a substituent. The aralkyl group, the aromatic ring group which may have a substituent or the heterocyclic group which may have a substituent are shown.

Specifically, the aryl group is a group such as phenyl, naphthyl and anthranyl, the alkyl group is a group such as methyl, ethyl and propyl, and the aralkyl group is a group such as benzyl, phenethyl and naphthylmethyl,
Examples of the aromatic ring group include groups such as phenyl and naphthyl, examples of the heterocyclic group include groups such as piperidyl, pyrrolyl, pyrrolidine, quinoline, and thienyl, and examples of substituents of the above groups include alkyl groups such as methyl, ethyl and propyl. Examples thereof include alkoxy groups such as methoxy, ethoxy and propoxy, halogen atoms such as fluorine atom, chlorine atom and bromine atom, and substituted amino groups such as dimethylamino and diphenylamino.

Furthermore, in the present invention, Ar is a compound represented by the following general formula (II) in the compound represented by the general formula (I).

In the formula, R ₃ and R ₄ are the same or different, and may have an alkyl group such as methyl, ethyl, or propyl, which may have a substituent, aralkyl such as benzyl, phenethyl, or naphthylmethyl which may have a substituent. A group, a phenyl which may have a substituent, an aromatic ring group such as naphthyl, or a quinolyl which may have a substituent, a heterocyclic group such as thienyl,
Alternatively, R ₃ and R ₄ may form a ring with a nitrogen atom,
R ₅ and R ₆ are the same or different and each is a hydrogen atom, methyl,
It represents an alkyl group such as ethyl or propyl, an alkoxy group such as methoxy, ethoxy or propoxy, a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom, a nitro group, a cyano group or a substituted amino group represented by the following general formula (III). .

(In the formula, R ₃ and R ₄ have the same meanings as in the general formula (II)), and as the substituent in R ₃ and R ₄ , an alkyl group such as methyl, ethyl, propyl, methoxy, ethoxy, propoxy, or the like can be given. Alkoxy group, halogen atom such as fluorine atom, chlorine atom, bromine atom, dimethylamino,
Examples thereof include substituted amino groups such as diphenylamino.

The electrophotographic photosensitive member of the present invention has R ₁ in the general formula (I).
When both R ₂ and R ₂ are aromatic ring groups, it is provided as an electrophotographic photosensitive member having extremely excellent characteristics such as sensitivity in comparison with other cases.

The reason why the electrophotographic photosensitive member of the present invention exhibits good characteristics is not clear, but it is presumed that it is largely caused by the fact that it has a substituted amino group at the ortho position and is less likely to undergo photoisomerization.

Typical examples of the compound represented by formula (I) are listed below.

Synthesis Example (Synthesis of Exemplified Compound (1)) 22.8 g (104 mmol) of the compound of the above (2) was dissolved in 120 ml of glacial acetic acid in a 500 ml beaker, to which a solution of 7.9 g (114 mmol) of sodium nitrite in 12 ml of water was added.

After stirring at room temperature for 1 hour, 120 ml of methanol was added and the temperature was 25 ° C.
Below, 23.8 g (364 mmol) of zinc dust was gradually added. After the exotherm stopped, the mixture was stirred at room temperature for 30 minutes, and the precipitate was filtered off.

To the filtrate, 25.0 g (83 mmol) of the compound of (1) above was added to 70 m.
A solution dissolved in l of glacial acetic acid was added. The precipitated crystals are dispersed and washed with heated methanol, recrystallized using a mixed solvent of methyl ethyl ketone-methanol, and toluene-
It was purified with an alumina column and dried to obtain the target compound.

Yield 28.0 g Yield 65.2% Elemental analysis Calculated value (%) Measured value (%) C 85.85 85.81 H 6.04 5.99 N 8.11 8.07 In addition, compounds other than the above Synthesis Examples are generally synthesized by the same method.

In a preferred embodiment of the present invention, the compound represented by the above general formula (I) can be used as the charge transporting substance of the electrophotographic photoreceptor in which the photosensitive layer is functionally separated into the charge generating layer and the charge transporting layer.

The charge transport layer according to the present invention is preferably formed by applying a solution prepared by dissolving the compound represented by the general formula (I) and a binder in a suitable solvent and drying the solution. Examples of the binder used here include polyacrylate, polysulfone, polyamide, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin,
Examples thereof include vinyl acetate resin, phenol resin, epoxy resin, polyester, alkyd resin, polycarbonate, polyurethane or copolymers such as styrene-butadiene copolymer, styrene-acrylonitrile copolymer and styrene-maleic acid copolymer. In addition to such insulating polymers, organic photoconductive polymers such as polyvinyl carbazole, polyvinyl anthracene, and polyvinyl pyrene can be used.

The mixing ratio of the binder and the charge transport material is 10
The charge transport compound is preferably 10 to 500 parts by weight per 0 part by weight.

The charge transport layer is electrically connected to the charge generation layer described below, and has a function of receiving the charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. are doing. At this time, the charge transport layer may be laminated on the charge generation layer,
Further, it may be laminated below the charge generation layer. However, the charge transport layer is preferably laminated on the charge generation layer.

This charge transport layer cannot be made thicker than necessary because there is a limit to the transport of charge carriers. Generally, it is 5-40 microns and the preferred range is 10-30 microns.

The organic solvent used in forming the charge transport layer varies depending on the type of the binder used, or is preferably selected from those which do not dissolve the charge generation layer or the undercoat layer described below. Specific organic solvents include alcohols such as methanol, ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and dichlorohexanone, amides such as N, N-dimethylformamide and N, N-dimethylacetamide. , Sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, methylene chloride,
Aliphatic halogenated hydrocarbons such as dichloroethylene, carbon tetrachloride and trichloroethylene, and aromatics such as benzene, toluene, xylene, monochlorobenzene and dichlorobenzene can be used.

Coating can be performed using a coating method such as a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a Meyer bar coating method, a blade coating method, a roller coating method, and a curtain coating method.

Drying is preferably a method of drying by touching at room temperature and then drying by heating. The heat drying can be carried out at a temperature of 30 to 200 ° C. for 5 minutes to 2 hours while still or under blowing air.

The charge transport layer in the invention may contain various additives. For example, plasticizers such as diphenyl, m-terphenyl and dibutyl phthalate, silicone oils, graft type silicone polymers, surface lubricants such as various fluorocarbons, potential stabilizers such as dicyanovinyl compounds and carbazole derivatives, β-carotene, Ni
Examples thereof include complexes and antioxidants such as 1,4-diazabicyclo [2,2,2] octane.

The charge generating layer used in the present invention is an inorganic charge generating substance such as selenium, selenium-tellurium, and amorphous silicon, a pyrylium-based dye, a thiapyrylium-based dye, an azurenium-based dye, a thiacyanine-based dye, a cationic dye such as a quinocyanine-based dye, and a scubarylium salt. Dyes, phthalocyanine pigments, anthanthrone pigments, dibenzpyrenequinone pigments, polycyclic quinone pigments such as pyrantrone pigments, indigo pigments, quinacridone pigments, azo pigments, etc. These materials can be used alone or in combination as a vapor deposition layer or coating layer.

Among the above-mentioned charge generating substances used in the present invention, the azo pigments are particularly wide-ranging, but typical structural examples of the azo pigments having particularly high effects are shown below.

As a general formula of an azo pigment, the central skeleton is represented by A as follows,
Let Cp be the coupler portion and n = 2 or 3. A
Specific example of N = N-Cp) _n A Specific example of Cp And the like.

By combining these central skeleton A and the coupler Cp at any time, an azo pigment as a charge generating substance is formed.

The charge generation layer can be formed by dispersing the above-mentioned charge generation substance in an appropriate binder and coating it on a support, or can be formed by forming a vapor deposition film by a vacuum vapor deposition device. .

The binder can be selected from a wide range of insulating resins,
Further, it can be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene. Preferably, polyvinyl butyral, polyacrylate (polycondensation polymer of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinyl pyridine, cellulosic resin, urethane resin, casein. Insulating resins such as polyvinyl alcohol and polyvinylpyrrolidone can be used. The amount of the resin contained in the charge generation layer is at most 80% by weight, preferably at most 40% by weight.

Examples of the organic solvent used for coating include alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone, methyl ethyl ketone and cyclohexanone; amides such as N, N-dimethylformamide and N, N-dimethylacetamide; Sulfoxides such as sulfoxide, tetrahydrofuran, dioxane,
Ethers such as ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride and trichloroethylene or benzene, toluene, xylene, Aromatic compounds such as monochlorobenzene and dichlorobenzene can be used.

Coating can be performed using a coating method such as a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a Meyer bar coating method, a blade coating method, a roller coating method, and a curtain coating method.

The charge generation layer contains as much of the organic photoconductor as possible to obtain sufficient absorbance and is a thin film layer, such as a thin film layer, for injecting the charge carrier into the charge transport layer within the lifetime of the generated charge carrier. 5 microns or less, preferably 0.
A thin film layer having a film thickness of 01 to 1 micron is preferable. This means that most of the amount of incident light is absorbed by the charge generation layer and many charge carriers are generated, and it is necessary to inject the generated charge carriers into the charge transport layer without deactivating them due to recombination or traps. It is due to being there.

The photosensitive layer having a laminated structure of a charge generation layer and a charge transport layer is provided on a support having a conductive layer.

As the support having a conductive layer, the support itself has conductivity, for example, aluminum, aluminum alloy,
Copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold, platinum, etc. can be used. In addition, aluminum, aluminum alloy, indium oxide, tin oxide, indium oxide-tin oxide alloy, etc. can be vacuumized. Plastic having a layer formed by a vapor deposition method (for example, polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluoroethylene, etc.), conductive particles (for example, aluminum powder, titanium oxide, tin oxide, zinc oxide, Carbon black, silver particles, etc.) together with a suitable binder on a plastic or a support obtained by coating the above conductive support, a support obtained by impregnating plastic or paper with conductive particles, or a plastic having a conductive polymer. Can be used

An undercoat layer having a barrier function and an adhesive function may be provided between the conductive support and the photosensitive layer.

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

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

In the case of 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 material of the present invention has a hole transport property, and thus the surface of the charge transport layer needs to be negatively charged. When exposed after charging, holes generated in the charge generation layer in the exposed area are injected into the charge transport layer, then reach the surface to neutralize the negative charges, and the surface potential is attenuated to cause the gap between the exposed area and the unexposed area. Electrostatic contrast occurs. At the time of development, it is necessary to use a positively charged toner.

In another embodiment of the present invention, the above-mentioned azo pigments or U.S. Pat.Nos. 3,554,745, 3,567,438, 3586500, pyrylium dyes, thiapyrylium dyes, serenapyrylium dyes disclosed in, for example, 3586500 A photoconductive pigment or dye such as benzopyrylium dye, benzothiapyrylium dye, or naphthopyrylium dye can also be used as the sensitizer.

In another embodiment, a eutectic complex of a pyrylium dye disclosed in US Pat. No. 3,684,502 and an electrically insulating polymer having an alkylidene diarylene moiety can be used as a sensitizer.

This eutectic complex is, for example, halogenated 4- [4-bis- (2-chloroethyl) aminophenyl] -2,6-diphenylthiapyrylium perchlorate and poly (4,4'-isopropylidenediphenylene carbonate). Hydrocarbon solvent (for example, dichloromethane, chloroform, carbon tetrachloride, 1,1-dichloroethane, 1,2-dichloroethane, 1,
After dissolving in 1,2-trichloroethane, chlorobenzene, bromobenzene, 1,2-dichlorobenzene), this is dissolved in a non-polar solvent (e.g. hexane, octane, decane, 2,2,
4-trimethylbenzene, ligroin) is added to obtain a particulate eutectic complex.

The electrophotographic photosensitive member in this example contains 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 and the like can be contained as a binder.

The electrophotographic photoreceptor of the present invention is used not only for electrophotographic copying machines, but also for laser printers, CRT printers,
It is also widely used in electrophotographic application fields such as an electrophotographic plate making system.

The electrophotographic photosensitive member of the present invention has the advantages of high sensitivity and small fluctuations in the light potential and the dark potential when repeatedly charged and exposed.

[Examples] Example 1 5 g of a disazo pigment represented by the following structural formula was added to 2 g of butyral resin (degree of butyralization: 63 mol%) and cyclohexanone 10
Disperse with a solution dissolved in 0 ml for 24 hours with a sand mill,
A coating liquid was prepared.

This coating solution was applied onto an aluminum sheet with a Meyer bar so that the dry film thickness would be 0.2 micron to form a charge generation layer.

Next, 10 g of the exemplified compound (54) as a charge-transporting substance and 10 g of polycarbonate (average molecular weight of 20,000) are dissolved in 70 g of monochlorobenzene, and this solution is applied on the charge-generating layer formed previously with a Meyer bar and dried. An electrophotographic photosensitive member was prepared by forming a charge transport layer having a film thickness of 20 μm.

This electrophotographic photosensitive member was statically tested at -5 KV using an electrostatic copying paper tester Model-SP-428 manufactured by Kawaguchi Electric Co., Ltd.
After corona charging in, and holding in the dark for 1 second, illuminance 20lux
It was exposed to light and the charging characteristics were measured.

As the charging characteristics, the exposure amount (E) required to attenuate the surface potential (V ₀ ) and the potential (V ₁ ) when dark attenuated for 1 second (1/2) is used.
1/2) was measured.

In addition, in order to measure the deterioration of the photoconductor due to light irradiation, only a part of the photoconductor prepared in this example has an illuminance of 1,500 lux.
After exposing it for 5 minutes in a dark place, it was kept in a dark place for 5 minutes and attached to a cylinder for a photosensitive drum of a PPC copier NP-3525 manufactured by Canon Inc. 5,000 copies were made with the same machine and the initial and 5,0
The fluctuations in the potential difference in the bright portion (ΔV _L ) and the potential difference in the dark portion (ΔV _D ) with respect to the non-history portion of the strong exposure history portion after copying 00 sheets were measured.

The dark part potential and the light part potential of the initial non-history portion were set to -700V and -200V, respectively. The results will be described later.

For comparison, a similar photoconductor was prepared using the compound (A) represented by the following structural formula instead of the exemplified compound as the charge transporting substance, and the same measurement was performed. The results are shown.

As is clear from the above, it can be seen that the electrophotographic photosensitive member of the present invention has good sensitivity and little potential fluctuation in the strong exposure history portion.

Examples 2 to 15 In each of these Examples, the compound (1), (2), (3)
(4), (5), (6), (7), (8), (9),
(16), (18), (19), (47) and (63) were used, and a pigment having the following structural formula was used as a charge generating substance, and an electrophotographic photosensitive member was obtained in the same manner as in Example 1. Created.

The electrophotographic characteristics of each photoconductor were measured by the same method as in Example 1. The results are shown.

Example 16 Aqueous ammonia solution of casein on an aluminum cylinder (casein 11.2 g, 28% ammonia water 1 g, water 22.2 m
l) was applied by a blade coating method to form an undercoat layer having a dry film thickness of 1 micron.

Next, 10 g of the charge generating substance represented by the following structural formula, 5 g of butyral resin (butyralization degree: 63 mol%) and 200 g of cyclohexanone were dispersed by a ball mill disperser for 48 hours. This dispersion was applied onto the undercoat layer by the blade coating method to form a charge generation layer having a dry film thickness of 0.15 μm.

Next, 10 g of Exemplified Compound (1) and 10 g of polymethylmethacrylate (average molecular weight of 50,000) were dissolved in 70 g of monochlorobenzene, and applied on the charge generation layer previously formed by the blade coating method to obtain a dry film thickness of 19 μm. Was formed on the charge transport layer.

Corrosion discharge of −5 KV was applied to the photoreceptor thus prepared.

The surface potential (initial potential V ₀ ) at this time was measured. Furthermore, the surface potential of this photoreceptor was measured after leaving it in the dark for 1 second.

The sensitivity was evaluated by measuring the exposure dose (E1 / 2 μJ / cm ² ) required to attenuate the potential V _k after dark decay to 1/2.

At this time, a gallium / aluminum / arsenic ternary semiconductor laser (output 5 mW, oscillation wavelength 780 nm) was used as a light source. The results are shown.

V ₀ : −703V V ₁ : −690V E1 / 2: 2.0μJ / cm ² Next, a laser beam printer (trade name LBP-CX, Canon ( The photoconductor of the present invention) was replaced with the photoconductor of the present invention and set, and an actual image forming test was carried out under the conditions shown below.

Surface potential after primary charging: -700 V, the surface potential after image exposure: -150 V (exposure quantity 2.0μJ / cm ^2), transfer potential: + 700 V,
Developer polarity: negative polarity, process speed: 50 mm / sec, development condition (development bias): -450 V, image exposure scan method: image scan, pre-priming exposure: 50 lux, sec full red exposure.

Image formation was performed by laser scanning with a laser beam according to a character signal and an image signal, and good prints were obtained for both characters and images.

Furthermore, when 3,000 continuous images were output, stable and good prints were obtained from the initial stage to 3,000 pages.

Example 17 3 g of 4- (4-dimethylaminophenyl) -2,6-diphenylthiapyrylium perchlorate and 5 g of the exemplified compound (2) were mixed with polyester (polyester adhesive).
49000: manufactured by DuPont) was mixed with 100 ml of a toluene-dioxane (50 parts by weight: 50 parts by weight) solution and dispersed by a ball mill for 6 hours. This dispersion was applied on an aluminum sheet with a Meyer bar so that the film thickness after drying would be 15 microns.

The electrophotographic characteristics of the thus prepared photoconductor were measured by the same method as in Example 1. The results are shown below.

V ₀ : −704V, V ₁ : −685V E1 / 2: 2.8lux, sec Initial potential difference ΔV _D : + 20V, ΔV _L : ± 0V Potential difference after 5,000 sheets endurance ΔV _D : + 20V, ΔV _L : + 20V Example 184 After sufficiently dissolving 3 g of-(4-dimethylaminophenyl) -2,6-diphenylthiapyrylium perchlorate and 3 g of poly (4,4-isopropylidene diphenylene carbonate) in 200 ml of dichloromethane, 100 ml of toluene was added and the mixture was added. The crystalline complex was precipitated. After this precipitate was filtered off, dichloromethane was added to redissolve it, and then 100 ml 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 in a ball mill for 6 hours. This dispersion was applied on an aluminum plate having a casein layer by a Meyer bar so as to have a thickness of 0.4 μm after being dried to form a charge generation layer.

Next, the exemplary compound (4), which is a charge-transporting substance, was used, and a charge-transporting layer was formed on the charge-generating layer in the same manner as in Example 1 except for the above.

The electrophotographic characteristics of the thus prepared photoconductor were measured by the same method as in Example 1.

The results are shown below.

V ₀ : -700V, V ₁ : -690V E1 / 2: 2.6lux, sec Initial potential difference ΔV _D : + 10V, ΔV _L : ± 0V Potential difference after 5000 sheets endurance ΔV _D : + 20V, _VL : + 20V Example 19 Aluminum An aqueous ammonia solution of casein (described above) was applied to the plate with a Meyer bar to form an undercoat layer having a dry film thickness of 1 micron. An electrophotographic photosensitive member was prepared in the same manner as in Example 6 except that the charge transport layer and the charge generation layer of Example 6 were sequentially laminated thereon, and the layer structure was different, and the charging characteristics were the same as in Example 1. Was measured. However, the charging polarity was +.
The results are shown.

V ₀ : + 705V, V ₁ : + 690V E1 / 2: 3.1lux, sec Initial potential difference ΔV _D : ± 0V, ΔV _L : + 10V Potential difference after 5,000 sheets endurance ΔV _D : + 20V, _VL : + 10V Example 20 On aluminum plate A 5% methanol solution of soluble nylon (6-66-610-12 quaternary nylon copolymer) was applied to the above to form an undercoat layer having a dry film thickness of 0.5 micron.

Next, 5 g of a pigment having the following structural formula was added to tetrahydrofuran.
It was dispersed in a sand mill for 20 hours in 95 ml.

Next, 5 g of the charge transport substance of Exemplified Compound (7) and bisphenol Z type polycarbonate (viscosity average molecular weight 30,000)
A liquid prepared by dissolving 10 g of the product in 30 ml of monochlorobenzene was added to the previously prepared dispersion liquid, and the mixture was further dispersed by a sand mill for 2 hours.

This dispersion was applied onto the above-mentioned undercoat layer with a Meyer bar so that the film thickness after drying was 20 μm, and dried.

The electrophotographic characteristics of the electrophotographic photosensitive member thus prepared were measured by the same method as in Example 1. The results are shown.

V ₀ : −702V, V ₁ : −687V E1 / 2: 2.9lux, sec Initial potential difference ΔV _D : + 10V, ΔV _L : + 10V Potential difference after 5,000 sheets endurance ΔV _D : + 20V, _VL : + 10V [Effect of the invention] The electrophotographic photoreceptor containing the specific compound according to the present invention has a high sensitivity, and the fluctuations in the light portion potential and the potential portion in the continuous image formation by repeated charging / exposure are small,
Has excellent durability.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 54-150128 (JP, A) JP 55-52064 (JP, A) JP 57-101844 (JP, A) JP 58- 199352 (JP, A)

Claims (2)

[Claims] 1. An electrophotographic photosensitive member comprising a photosensitive layer laminated on a conductive support, wherein the photosensitive layer contains a compound represented by the following general formula (I). In the formula, Ar represents an aryl group having a substituted amino group at least in the ortho position, R ₁ and R ₂ are the same or different, and may have an alkyl group which may have a substituent, or a substituent which may have a substituent. The aralkyl group, the aromatic ring group which may have a substituent or the heterocyclic group which may have a substituent are shown. 2. A compound represented by the general formula (I),
The electrophotographic photosensitive member according to claim 1, wherein Ar is a compound represented by the following general formula (II). In the formula, R ₃ and R ₄ are the same or different, and may be an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aromatic ring group which may have a substituent or a substituent. Represents a heterocyclic group which may have a group, or R ₃ and R ₄ may form a ring together with a nitrogen atom, R ₅ and R ₆ are the same or different and are a hydrogen atom, an alkyl group or an alkoxy group. A group, a halogen atom, a nitro group, a cyano group or a substituted amino group is shown.