JPH0812430B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: 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] Inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been conventionally known as photoconductive materials used in electrophotographic photoreceptors.

While these photoconductive materials have many advantages, for example, they can be charged to a proper potential in the dark, that the dissipation of charges is small in the dark, or that they can be rapidly dissipated by light irradiation, , Has various drawbacks.

For example, selenium-based photoconductors easily crystallize due to factors such as temperature, humidity, dust, and pressure. In particular, when the ambient temperature exceeds 40 ° C, crystallization becomes remarkable, resulting in a decrease in chargeability and spots on images. There are drawbacks such as. Cadmium sulfide-based photoconductors do not provide stable sensitivity in humid environments, and zinc oxide-based photoconductors require the sensitizing effect of sensitizing dyes typified by rose bengal. The dye has a drawback that a stable image cannot be provided for a long period of time because it causes charge deterioration due to corona charging and discoloration due to exposure light.

On the other hand, various organic photoconductive polymers such as polyvinylcarbazole have been proposed, but these polymers are superior to the above-mentioned inorganic photoconductive materials in film forming property and lightness. Despite this, it has been difficult to put it into practical use until now, because the film-forming property has not been obtained yet, and the inorganic photoconductivity is high in terms of sensitivity, durability and stability due to environmental changes. This is because it is inferior to the material.

Further, hydrazone compounds disclosed 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, etc. A low molecular weight organic photoconductor such as the 9-styrylanthracene compound described in 1) has been proposed. Such a low molecular weight organic photoconductor, by properly selecting the binder to be used, it has become possible to eliminate the drawback of film-forming property which 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. An electrophotographic photosensitive member using this laminated structure as a photosensitive layer,
It has become possible to improve the sensitivity to visible light, the charge retention, and the surface strength.

Such an electrophotographic photoreceptor is disclosed, for example, in US Pat.
No. 851, U.S. Pat. No. 3,871,882, and the like.

However, the sensitivity and the characteristics are not always sufficient in the electrophotographic photosensitive member using the conventional low molecular weight organic photoconductor for the charge transport layer, and in particular, when the charging and the exposure are repeated, the potentials of the bright portion and the dark portion are not increased. There is a lot of fluctuation and there are points that need improvement.

[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, and to further provide a charge generation layer. It is to provide a novel charge transporting material in a laminated type photosensitive layer which is functionally separated into a charge transporting layer.

[Means and Actions for Solving Problems] The present invention is constituted by an electrophotographic photoreceptor having a layer containing a carbazole compound represented by the following general formula.

General formula In the formula, R ₁ represents an alkyl group such as methyl, ethyl, propyl, or butyl which may have a substituent, benzyl, phenethyl, an aralkyl group such as naphthylmethyl or an aryl group such as phenyl or naphthyl, and R ₂ to R ₈ is a hydrogen atom, a fluorine atom, a chlorine atom, a halogen atom such as a bromine atom, optionally substituted methyl, ethyl, propyl,
It represents an alkyl group such as butyl, an alkoxy group such as phenoxy, methoxy, ethoxy, and propoxy, or an amino group, and R ₂ and R ₃ , R ₃ and R ₄ , R ₄ and R _5, and R ₆ and R ₇ are substituted, respectively. Represents a residue forming a benzene ring which may have a group, and A is phenyl which may have a substituent,
An aromatic ring group such as naphthyl or a heteroaromatic ring group such as pyridyl, indolyl, quinolyl, and benzothienyl is shown. Then, the alkyl group, aralkyl group, aryl group, alkoxy group, amino group, benzene ring-forming residue, aromatic ring group, or alkyl group such as methyl, ethyl, or propyl as a substituent that the heteroaromatic ring group may have. , Alkoxy groups such as methoxy, ethoxy, and propoxy, fluorine atoms,
Examples thereof include halogen atoms such as chlorine atom and bromine atom, cyano group, nitro group, substituted amino group, and the like, wherein the substituent of the substituted amino group is an alkyl group such as methyl, ethyl, propyl, or butyl, or an alkyl group, an alkoxy group. ,
Examples thereof include an aromatic ring group which may have a substituent such as a halogen atom, a nitro group and a cyano group.

Representative examples of the carbazole compound represented by the above general formula in the present invention are shown below.

Regarding the synthesis of the carbazole compound represented by the above general formula, the synthesis method of the compound example (4) will be described as a representative example.

9-Ethyl-3-diazonium carbazole tetrafluoroborate 10.0 g (32.3 mmol) was added to nitrobenzene 32
In addition to 0 cc, 6.34 g (64.6 mmol) of potassium acetate and 1.2 cc of acetonitrile are added, and the mixture is vigorously stirred for 2 hours. The reaction solution is washed with water, dried over anhydrous sodium sulfate, and nitrobenzene and the like are distilled off under reduced pressure.

The residue was purified by a silica gel column to obtain 9.41 g of 3- (p-nitrophenyl) -9-ethylcarbazole. This was reduced and ethylated by a usual method to obtain 9.11 g of the desired compound.

 The yield was 82.9%.

Elemental analysis value Calculated value (%) Measured value (%) C 84.42 84.38 H 7.38 7.41 N 8.20 8.21 Other exemplified carbazole compounds can be synthesized by the same method.

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

The charge transport layer in the present invention is preferably formed by applying a solution in which a carbazole compound represented by the above general formula and a binder are dissolved in a suitable solvent and drying the solution.

As the binder, for example, polyarylate, polysulfone, polyamide, acrylic resin, acrylonitrile resin, methacrylic resin, polyvinyl chloride, polyvinyl acetate, phenol resin, epoxy resin, polyester, alkyd resin, polycarbonate, polyurethane or a resin of these Copolymers containing two or more repeating units such as styrene-butadiene copolymer, styrene-
Mention may be made of acrylonitrile copolymers, styrene-maleic acid copolymers and the like. Besides such an insulating resin, an organic photoconductive polymer such as polyvinylcarbazole, polyvinylanthracene or polyvinylpyrene can be used.

The mixing ratio of the binder and the carbazole compound is
The carbazole compound is preferably 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 described below and has a function of receiving an electric carrier injected from the charge generation layer in the presence of an electric field and capable of transporting these charge carriers to the surface. are doing. At this time, the charge transport layer may be stacked on or below the charge generation layer. However, the charge transport layer is preferably laminated on the charge generation layer.

Since the charge transport layer has a limit for transporting charge carriers, it cannot be made thicker than necessary. Generally, it is 5 to 30μ, but a preferable range is 8 to 20μ.

The solvent used when forming the charge transport layer varies depending on the kind of the binder used, or is preferably selected from those which do not dissolve the charge generation layer or the undercoat layer described below.

For example, methanol, ethanol, alcohols such as isopropanol, acetone, methyl ethyl ketone, ketones such as cyclohexane, N, N-dimethylformamide, N, N-dimethylacetamide and other amides, dimethyl sulfoxide and other sulfoxides, 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 hydrocarbons such as ligroin, monochlorobenzene and dichlorobenzene can be used.

The coating can be performed by 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 performed at 30 to 200 ° C. for 5 minutes to 2 hours in a static state or under blowing air.

Various additives can be contained in the charge transport layer.

Such additives include diphenyl, diphenyl chloride, o-terphenyl, p-terphenyl, dibutyl phthalate, dimethyl glycol phthalate, dioctyl phthalate, triphenyl phosphoric acid, methylnaphthalene,
Examples thereof include benzophenone, chlorinated paraffin, dilauryl thiopropionate, 3,5-dinitrosalicylic acid and various fluorocarbons.

The charge generation layer in the present invention is selenium, selenium-tellurium, pyrylium dye, thiapyrylium dye, azurenium dye, phthalocyanine pigment, anthanthrone pigment,
Dibenzpyrenequinone pigment, pyranthrone pigment, trisazo pigment, disazo pigment, monoazo pigment, indigo pigment, quinacridone pigment, thiacyanine, asymmetric quinocyanine, quinocyanine, or charge generating substance such as amorphous silicon described in JP-A-54-143645 Can be used to form a vapor deposition layer or a resin dispersion layer.

Examples of the charge generating substance used in the electrophotographic photosensitive member of the present invention include the following inorganic compounds and organic compounds.

Charge generation materials (1) Amorphous silicon (2) Selenium-tellurium (3) Selenium-arsenic (4) Cadmium sulfide (58) Squaric acid methine dye (59) Indigo dye (60) Thioindigo dye (61) β-type copper phthalocyanine The charge generation layer can be formed by dispersing the above-mentioned charge generation substance in a suitable binder and coating it on a substrate, or can also be obtained by forming a vapor deposition film by a vacuum vapor deposition device. it can.

The binder that can be used when forming the charge generation layer by coating can be selected from a wide range of insulating resins, and can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene. To be done.

Preferred are polyvinyl butyral, polyarylate (polycondensation polymer of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinyl pyridine, cellulosic resin, polyurethane, casein. Insulating resins such as polyvinyl alcohol and polyvinylpyrrolidone can be used.

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

As the solvent used in coating, methanol, ethanol, alcohols such as isopropanol, acetone, methyl ethyl ketone, ketones such as cyclohexanone, N, N-dimethylformamide, amides such as N, N-dimethylacetamide, dimethyl sulfoxide. Sulfoxides such as, tetrahydrofuran, dioxane, ethers such as ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, aliphatic halogenated carbonization such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride and trichloroethylene Examples thereof include hydrogens, aromatic hydrocarbons such as benzene, toluene, xylene, ligroin, monochlorobenzene, and dichlorobenzene.

The coating can be carried out 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 or a curtain coating method.

The charge generation layer contains as much of the charge generation material as possible to obtain sufficient absorbance, and in order to shorten the range of the generated charge carrier, a thin film layer such as 5
A thin film layer having a thickness of less than or equal to μ, preferably 0.01 to 1 μ is desirable.

This means that most of the amount of incident light is absorbed by the charge generation layer, generating a large number of charge carriers, and the generated charge carriers are injected into the charge transport layer without being deactivated by recombination or trapping. Is due to the need to.

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

As the substrate having a conductive layer, if the substrate itself has conductivity, for example, aluminum, aluminum alloy,
Copper, zinc, stainless steel, vanadium molybdenum, chromium, titanium, nickel, indium, gold, platinum and the like can be mentioned. In addition, aluminum, aluminum alloy, indium oxide, tin oxide, indium oxide-tin oxide alloy, etc. can be vacuum-deposited. A plastic having a layer coated by (eg polyethylene, polypropylene,
Polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluoroethylene, etc.), conductive particles (for example, carbon black, silver particles, etc.) coated on a plastic with a suitable binder, conductive particles contained in plastic or paper. Examples include a corroded substrate and a plastic having a conductive polymer.

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

The subbing layer is made 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 be formed.

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

In the case of using a photoconductor in which a conductive layer, a charge generation layer and a charge transport layer are laminated in this order, the carbazole compound represented by the above general formula of the present invention has a hole transport property, and thus the surface of the charge transport layer is negatively charged. When exposed after charging, holes generated in the charge generation layer are injected into the charge transport layer in the exposed portion, and then reach the surface to neutralize the negative charge,
The surface potential is attenuated, and electrostatic contrast is generated between the surface and the unexposed portion. At the time of development, it is necessary to use a positively charged toner.

In another embodiment of the present invention, disazo pigments or U.S. Pat.Nos. 3,554,745, 3,567,438, 35,
Use of a photoconductive pigment or dye such as pyrylium dye, thiapyrylium dye, selenapylylium dye, benzopyrylium dye, benzothiapyrylium dye, or naphthopyrylium dye disclosed in 86500 as a sensitizer You can

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,
Obtained as a particulate eutectic complex by adding 4-trimethylbenzene and ligroin.

The electrophotographic photoreceptor in this specific example includes styrene-
Butadiene copolymer, silicone resin, vinyl resin,
Vinylidene chloride-acrylonitrile copolymer, styrene-acrylonitrile copolymer, vinyl acetate-
A vinyl chloride copolymer, polyvinyl butyral, polymethyl methacrylate, poly-N-butyl methacrylate, polyester resin, cellulose ester 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.

[Example] Example 1 β-type copper phthalocyanine (trade name: Lionnl Blue NCB Tone
r, Toyo Ink Mfg. Co., Ltd.) was sequentially refluxed in water, ethanol and benzene, and then filtered and purified to give 7 g of pigment, product name Polyester Adhesive 49000 (solid content 20%, made by DuPont) 14 g, toluene 35 g and dioxane 35 g were mixed and dispersed by a ball mill for 6 hours to prepare a coating liquid. This coating liquid was applied on an aluminum sheet with a Meyer bar so that the dry film thickness was 0.5 μm to form a charge generation layer.

Next, 7 g of a compound of the carbazole compound (4) and 7 g of a polycarbonate (trade name: Panlite K-1300, manufactured by Teijin Ltd.) as a charge-transporting substance were added to tetrahydrofuran.
A solution obtained by stirring and dissolving in a mixed solvent of 35 g and 35 g of chlorobenzene was applied onto the above charge generation layer with a Meyer bar to a dry film thickness of 11 μ, and a photosensitive layer consisting of a two-layer structure. Was prepared.

This electrophotographic photosensitive member was corona-charged at -5 KV by a static method using an electrostatic copying paper tester Model-SP-428 manufactured by Kawaguchi Electric Co., Ltd., kept for 1 second in a dark place, and then exposed at an illuminance of 5 lux. 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.

Furthermore, in order to measure the fluctuation of the light potential and the dark potential when the electrophotographic photosensitive member created above is repeatedly used,
PPC copier manufactured by Canon Inc., affixed to the cylinder for photosensitive drum of product name NP-150Z, and made 50,000 copies with the same machine. Bright area potential ( _VL ) and dark area potential (V _L ) and dark area potential at the initial and after copying 50,000 sheets ( The variation of V _D ) was measured.

Further, instead of the carbazole compound example (4), a structural formula Comparative Material 1 was prepared in the same manner as in Example 1 except that the compound of Example 1 was used, and the same measurement was performed.

 The results are shown below.

As is clear from the above results, the electrophotographic photoreceptor using the carbazole compound represented by the general formula of the present invention in the charge transport layer has high sensitivity and high durability.

Examples 2 to 16 In this example, instead of the charge transport material used in Example 1, the carbazole compound examples (2), (5), (6), (7), (8) represented by the above general formula are used. ),(Ten),
(13), (16), (18), (20), (22), (23),
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the compounds (27), (28) and (32) were used and the pigment (44) illustrated as the charge generating substance was used.

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

Example 17 Aqueous ammonia solution of casein on aluminum cylinder (casein 11.2 g, 28% ammonia water 1 g, water 222 ml)
Is applied by the dip coating method and dried to apply a coating amount of 1.0 g / m
An undercoat layer of ² was formed.

Next, 1 part by weight of the pigment of the exemplary pigment (78) as a charge generating substance, 1 part by weight of butyral resin (trade name S-REC BM-2, manufactured by Sekisui Chemical Co., Ltd.) and 30 parts by weight of isopropyl alcohol were dispersed in a ball mill for 4 hours. did. This dispersion was applied onto the above-mentioned undercoat layer by a dip coating method and dried to form a charge generation layer. This film thickness was 0.3 μm.

Next, 1 part by weight of the charge-transporting substance of the carbazole compound example (3), 1 part by weight of polysulfone (P-1700, manufactured by UCC), and 6 parts by weight of monochlorobenzene were mixed, and stirred and dissolved by a stirrer. This liquid was applied onto the above charge generation layer by a dip coating method and dried to form a charge transport layer. The film thickness was 12μ.

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

The surface potential (initial potential V ₀ ) at this time was measured. Further, the surface potential of the photoconductor after being left in the dark for 5 seconds was measured (attenuation).

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 : −685V Potential holding ratio (V _K / V ₀ × 100): 95% E1 / 2: 2.1 μJ / cm ² Laser beam, a reversal development type electrophotographic printer equipped with the same semiconductor laser as above. The photoconductor of the printer (trade name LBP-LX, manufactured by Canon Inc.) 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 1.2μJ / cm ^2), transfer potential: +700
V, developer polarity: negative polarity, process speed: 50 mm / sec,
Development condition (development bias): -450V, image exposure scan method: image scan, exposure before primary charging: 500lux, 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.

Example 18 3 g of 4- (4-dimethylaminophenyl) -2,6-diphenylthiapyrylium perchlorate and 5 g of the charge-transporting substance of the above carbazole compound example (14) were replaced with toluene-dioxane ( 50:50) solution 100ml
And dispersed in 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 was 15 μm.

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 : −688V, V ₁ : −678V E1 / 2: 2.4 lux, sec Initial V _D : −687V, _VL : −143V After 50,000 sheets durability V _D : −677V, _VL : −171V Example 19 Aqueous ammonia solution of casein (casein
11.2 g, 28% ammonia water 1 g, and water 222 ml) were applied and dried with a Meyer bar to form an adhesive layer having a film thickness of 1 μm.

Next, 5 g of the disazo pigment of the charge generating substance example (16) and 2 g of butyral resin (butyralization degree 63%) were added to 95 ml of ethanol.
After being dispersed together with the liquid dissolved in the above, it was coated on the adhesive layer to form a charge generation layer having a film thickness after drying of 0.4 μm.

Next, 5 g of the charge-transporting substance of the carbazole compound example (2) and 5 g of poly-4,4'dioxydiphenyl-2,2-propanecarbonate (viscosity average molecular weight 30,000) dissolved in 150 ml of dichloromethane were charged. Apply and dry on the generation layer,
An electrophotographic photoreceptor was prepared by forming a charge transport layer having a film thickness of 11 μm.

The electrophotographic characteristics of this photoreceptor were measured in the same manner as in Example 1. The results are shown below.

V ₀ : −689V, V ₁ : −680V E1 / 2: 2.0lux, sec Initial V _D : −688V, _VL : −138V After 50,000 sheets endurance V _D : −678V, _VL : −159V Example 20 0.2mm thick molybdenum plate (substrate) with clean surface
Was fixed in place in the glow discharge deposition tank. Next, the inside of the tank was evacuated to a vacuum degree of about 5 × 10 ⁻⁶ torr. After that, the input voltage of the heater was increased to stabilize the molybdenum substrate temperature at 150 ° C. After that, hydrogen gas and silane gas (15% by volume relative to hydrogen gas) were introduced into the tank, and the gas flow rate and the main valve of the evaporation tank were adjusted to stabilize at 0.5 torr. Next, high-frequency power of 5 MHz was applied to the induction coil to generate glow discharge inside the coil and set the input power to 30 W. Under the above conditions, an amorphous silicon film is grown on the substrate, and the film thickness is 2
After maintaining the same conditions until the value became μ, the glow discharge was stopped. After that, turn off the heater and high frequency power,
After waiting for the substrate temperature to reach 100 ° C., the outflow valves for hydrogen gas and silane gas were closed, the inside of the tank was once brought to 10 ⁻⁵ torr or less, and then returned to atmospheric pressure and the substrate was taken out.

Next, a charge transport layer was formed on this amorphous silicon layer in the same manner as in Example 1 except that the above carbazole compound example was used as the charge transport material. The photoconductor thus created was installed in the charging exposure experimental device, and -6KV
It was corona-charged and immediately irradiated with a light image. The light image was illuminated through a transmissive test chart using a tungsten lamp light source. Immediately thereafter, a positively chargeable developer (including a toner and a carrier) was cascaded on the surface of the photoconductor to obtain a good toner image on the surface of the photoconductor.

Example 21 3 g of 4- (4-dimethylaminophenyl) -2,6-diphenylthiapyrylium perchlorate and poly (4,4'-
3 g of isopropylidene diphenylene carbonate) and 200 ml of dichloromethane were sufficiently dissolved, and then 100 ml of toluene was added.
Was added to precipitate the eutectic complex. After the precipitate was separated by filtration, dichloromethane was added to redissolve it, and then 100 ml of n-hexane was added to the 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 is applied on an aluminum plate having a casein layer by a Meyer bar so that the film thickness becomes 0.4μ after drying,
A charge generation layer was formed.

Next, a charge transporting layer was formed on the charge generating layer in the same manner as in Example 1 except that the substance of the carbazole compound example (21), which was a charge transporting substance, was used. 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 : −690V, V ₁ : −684V E1 / 2: 2.9lux, sec Initial V _D : −687V, _VL : −147V After endurance of 50,000 sheets V _D : −680V, _VL : −170V Example 22 5 g of a eutectic complex similar to the eutectic complex used in Example 21 and 5 g of the charge-transporting substance of the carbazole compound example (4) were added to 150 ml of a tetrahydrofuran solution of polyester (described above), and they were sufficiently mixed and stirred. This solution was applied onto an aluminum sheet with a Meyer bar so that the film thickness after drying would be 15 μm. The electrophotographic characteristics of this photoreceptor were measured in the same manner as in Example 1. The results are shown.

V ₀ : −688V, V ₁ : −679V E1 / 2: 2.0lux, sec Initial V _D : −687V, _VL : −139V After 50,000 sheets durability V _D : −680V, _VL : −157V [Invention Effect] The electrophotographic photosensitive member of the present invention has high sensitivity, since the specific carbazole compound is used as the charge transport material.
High durability (potential fluctuation due to repeated use is extremely small)
In addition, it has a remarkable effect that it can be applied to a wide range of electrophotographic fields.

Continuation of front page (56) Reference JP-A-60-135953 (JP, A) JP-A-54-5433 (JP, A) JP-A-61-218587 (JP, A)

Claims (1)

[Claims] 1. An electrophotographic photosensitive member having a layer containing a carbazole compound represented by the following general formula. General formula In the formula, R ₁ represents an alkyl group which may have a substituent, an aralkyl group or an aryl group, and R _{2 to} R ₈ represent a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an alkoxy group. Alternatively, it represents an amino group, further R ₂ and R ₃ , R ₃ and
R ₄ , R ₄ and R _5, and R ₆ and R ₇ represent a benzene ring-forming residue which may have a substituent, and A represents phenyl, naphthyl,
It represents a pyridyl, indolyl, quinolyl or benzothienyl group, and any of these groups may have a substituent.