JPH073587B2 - 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 weight organic photoconductor that provides improved electrophotographic properties. is there.

[Prior art]

Inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been known as photoconductive materials used in electrophotographic photoreceptors. These photoconductive materials have many advantages, such as being able to be charged to an appropriate potential in a dark place, less dissipation of charges in a dark place, or being capable of rapidly dissipating charges by light irradiation. , Has various drawbacks. For example, selenium-based photoreceptors easily crystallize due to factors such as temperature, humidity, dust, and pressure.In particular, when the ambient temperature exceeds 40 ° C, crystallization becomes noticeable, resulting in reduced chargeability and white spots on images. There is a drawback that occurs. Cadmium sulfide-based photoconductors cannot obtain stable sensitivity in a humid environment, and zinc sulfide-based photoconductors require the sensitizing effect of a sensitizing dye represented by rose bengal. There is a drawback that a stable image cannot be provided for a long period of time because the photosensitive dye causes charge deterioration due to corona charging and photobleaching 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 light weight. Nevertheless, it has been difficult to put it into practical use until today because it has not been able to obtain sufficient film-forming properties, and it is not suitable for inorganic photoconductive materials because of its sensitivity, durability, and stability due to environmental changes. It was because it was inferior.
Further, hydrazone compounds disclosed in US Pat. No. 4,150,987, triaryl pyrazoline compounds described in US Pat. No. 3837851, JP-A-51-94828,
A low molecular weight organic photoconductor such as a 9-styrylanthracel compound described in JP-A-51-94829 is proposed. Such low molecular weight organic photoconductor, by properly selecting the binder to be used, it has become possible to solve 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.

Under these circumstances, in recent years, a laminated structure has been proposed in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer. An electrophotographic photosensitive member 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 electrophotographic photoreceptors are disclosed, for example, in US Pat. Nos. 3,838,851 and 3,871,882.

However, the sensitivity and characteristics are not always sufficient in the electrophotographic photoreceptor using the conventional low molecular weight organic photoconductor for the charge transport layer, and the bright part is not visible when repeatedly charged and exposed. There is a point that the fluctuations of the potential and the dark part 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 eliminates the above-mentioned drawbacks or disadvantages.

Another object of the present invention is to provide a novel organic photoconductor.

Another object of the present invention is to provide a novel charge transport material in a laminated type photosensitive layer in which a charge generation layer and a charge transport layer are functionally separated.

[Means for solving problems]

That is, the present invention is an electrophotographic photoreceptor having a layer containing a compound represented by the following general formula.

General formula (In the formula, R ₁ represents an alkyl group which may have a substituent or an aralkyl group, and R ₂ , R ₃ , R ₄ and R ₅ may be an alkyl group which may have a substituent, an aralkyl group or an aryl group. A group or a heterocyclic group, R ₂ and R ₃ or R ₄ and R ₅ may be bonded to form a 5- or 6-membered ring together with the nitrogen atom in the formula, and X ₁ and X ₂ are hydrogen atoms. ,
Halogen atom, alkyl group, alkoxy group, nitro group,
A cyano group and a trifluoromethyl group are shown. Here, R ₁ represents an alkyl group such as methyl, ethyl, propyl or butyl, or an aralkyl group such as benzyl, phenethyl or naphthylmethyl. These alkyl groups and aralkyl groups are halogen atoms such as fluorine, chlorine, bromine and iodine, alkyl groups such as methyl, ethyl, propyl and butyl, alkoxy groups such as methoxy, ethoxy, propoxy and butoxy, aralkyl such as benzyl and phenethyl. It may be substituted with a group, an aryl group such as phenyl, naphthyl or fluorenyl, a substituted amino group such as diethylamino, dibutylamino or diphenylamino, a nitro group or a cyano group.

R ₂ , R ₃ , R ₄ and R ₅ are alkyl groups such as methyl, ethyl, propyl and butyl, aralkyl groups such as benzyl, phenethyl and naphthylmethyl, aryl groups such as phenyl, naphthyl and fluorenyl, or pyridyl, quinolyl, Furyl, thienyl, pyryl, oxazolyl, thiazolyl, imidazolyl, triazolyl, oxadiazolyl, thiadiazolyl, indolyl, carbazolyl, benzoxazolyl,
Heterocyclic groups such as benzothiazolyl, benzimidazolyl and benzotriazolyl are shown. These alkyl groups, aralkyl groups, aryl groups and heterocyclic groups are halogen atoms such as fluorine, chlorine, bromine and iodine, alkyl groups such as methyl, ethyl, propyl and butyl, alkoxy such as methoxy, ethoxy, propoxy and butoxy. Groups, aralkyl groups such as benzyl and phenethyl, aryl groups such as phenyl, naphthyl and fluorenyl, substituted amino groups such as diethylamino, dibutylamino and diphenylamino, nitro groups, or cyano groups.

Further, R ₂ and R ₃ or R ₄ and R ₅ may combine with each other to form a 5- or 6-membered ring such as piperidino, piperazino, morpholino and carbazolyl together with the nitrogen atom in the formula.

X ₁ and X ₂ are a hydrogen atom, a halogen atom such as fluorine, chlorine, bromine and iodine, an alkyl group such as methyl, ethyl, propyl and butyl, an alkoxy group such as methoxy, ethoxy, propoxy and butkin, a nitro group and a cyano group. Or a trifluoromethyl group.

Typical examples of the compounds represented by the general formula will be given below.

Compound example Next, a synthesis example of the compound will be shown.

Synthesis Example (Synthesis of Compound No. (1)) N-Methyl-4,4'-diaminodiphenylamine 10.24 g
(0.048 mol) was dissolved in 200 ml of anhydrous tetrahydrofuran and oily sodium hydride (content 60
%) 5.80 g (0.145 mol) is slowly added. When foaming stops, bring to room temperature and stir for 30 minutes. Next, 11.6 ml (0.145 mol) of ethyl iodide was slowly added dropwise.
Stir for 0 minutes at room temperature. Then, the mixture is stirred under reflux for another 8 hours. After the reaction was completed, the reaction product was poured into water 1 and extracted with ethyl acetate.
It is extracted twice with 300 ml, and the ethyl acetate layer is washed with water and dried over sodium sulfate. The solvent was distilled off under reduced pressure, and the residue was recrystallized from cyclohexane to which a small amount of ethyl acetate was added to obtain 12.0 g of crystals.
Yield 76.7% Elemental analysis value Calculated value Measured value C 77.49 77.31 H 9.60 9.53 N 12.91 12.94 For compounds other than the above-mentioned synthesis examples, the required diamino compound is generally used together with sodium hydride, alkyl iodide,
It is synthesized by a similar synthetic method in which an aralkyl halide, an aryl halide or the like is allowed to act. However, R ₂ , R ₃ ,
When R ₄ and R ₅ (the same as those shown in the claims) are different, for example, one of the required dinitro compounds is partially reduced to carry out the substitution reaction, and then the remaining nitro group is reduced again. Then, a procedure such as performing a substitution reaction is required.

In a preferred specific example of the present invention, the 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 according to the present invention is preferably formed by applying a solution prepared by dissolving the compound represented by the above general formula and a binder in a suitable solvent and drying the solution. Examples of the binder used here include polyarylate resin, polysulfone resin, polyamide resin, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenol resin, epoxy resin, polyester resin, alkyd resin, and polycarbonate. , A polyurethane or a copolymer resin containing two or more repeating units of these resins, such as styrene-
Examples thereof include butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer and the like. In addition to such insulating polymers, organic photoconductive polymers such as polyvinylcarbazole, polyvinylanthracene and polyvinylpyrene can also be used.

The compounding ratio of the binder and the compound is preferably 10 to 500 parts by weight of the compound 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 the charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. is doing. At this time, the charge transport layer may be laminated on or below the charge generation layer. However, the charge transport layer is
It is preferably laminated on the charge generation layer. Since this charge transport layer has a limit for transporting charge carriers, the film thickness cannot be increased more than necessary. Generally, it is 5 microns to 30 microns, but the preferred range is 8 microns to 20 microns.

The organic solvent used when forming such a charge transport layer is
It is preferable to select it depending on the kind of the binder used or one which does not dissolve the charge generation layer or the undercoat layer described below. Specific organic solvents include methanol, ethanol, alcohols such as isopropanol, acetone, methyl ethyl ketone, ketones such as cyclohexanone, N, N-dimethylformamide, amides such as N, N-dimethylacetamide, and dimethyl sulfoxide. Ethers such as sulfoxides, tetrahydrofuran, dioxane and 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. Alternatively, aromatic compounds such as benzene, toluene, xylene, ligroin, monochlorobenzene, and dichlorobenzene can be used.

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.
Drying is preferably a method of drying by touching at room temperature and then drying by heating. Heat drying at a temperature of 30 ℃ to 200 ℃ for 5 minutes to 2
It can be done statically or under blast for a time range of hours.

The charge transport layer of the present invention may contain various additives. Such additives include diphenyl, diphenyl chloride, o-terphenyl, p-terphenyl, dibutyl phthalate, dimethyl glycol phthalate, dioctyl phthalate, triphenyl phosphoric acid, methylnaphthalene, benzophenone, chlorinated paraffin, dilauryl thiopropionate, 3, Examples thereof include 5-dinitrosalicylic acid and various fluorocarbons.

The charge generation layer used in the present invention is selenium, selenium tellurium, pyrylium, thiopyrylium, azurenium dye, phthalocyanine pigment, anthanthrone pigment, dibenzpyrenequinone pigment, pyranthrone pigment, trisazo pigment, disazo pigment, azo pigment, indigo pigment, Quinacridone pigment, thiacyanine, asymmetric quinocyanine,
A separate vapor deposition layer or resin dispersion layer selected from quinocyanine or a charge generating substance such as amorphous silicon described in JP-A-54-143645 can be used.

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 material (1) Amorphous silicon (2) Selenium-tellurium (3) Selenium-arsenic (4) Cadmium sulfide (19) -2 Square methacrylic acid methine dye (19) -3 Indigo dye (CINo.78000) (19) -4 Thioindigo dye (CINo.78800) (19) -5β-type copper phthalocyanine The charge generation layer can be formed by dispersing the above-mentioned charge generation substance in an appropriate binder and coating it on a substrate, or can be obtained by forming a vapor deposition film by a vacuum vapor deposition device. . 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. . Preferably, polyvinyl butyral, polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin,
Examples of the insulating resin include polyacrylamide resin, polyamide, polyvinyl pyridine, cellulosic resin, urethane resin, epoxy resin, casein, polyvinyl alcohol and polyvinyl pyrrolidone. The resin contained in the charge generation layer is 80% by weight or less, preferably 40% by weight or less.
Weight% or less is suitable. As the organic solvent used during coating, methanol, ethanol, alcohols such as isopropanol, acetone, methyl ethyl ketone, ketones such as cyclohexanone, N, N-dimethylformamide, N, N-dimethylacetamide amides,
Sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, and aliphatic halogens such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene. Chemical hydrocarbons or aromatics such as benzene, toluene, xylene, ligroin, monochlorobenzene, and dichlorobenzene can be used.

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 organic photoconductor as possible in order to obtain sufficient absorbance, and in order to shorten the range of the generated charge carrier, a thin film layer, for example, 5 microns or less, preferably Is preferably a thin film layer having a thickness of 0.01 micron to 1 micron. This means that most of the amount of incident light is absorbed by the charge generation layer to generate a large number of charge carriers, and the generated charge carriers are not deactivated by recombination or capture (trap) to the charge transport layer. This is due to the need to inject.

The photosensitive layer having such a laminated structure of the charge generation layer and the charge transport layer is provided on the substrate having the conductive layer. The substrate having a conductive layer is a substrate having conductivity,
For example, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium,
Nickel, indium, gold, platinum or the like can be used, and in addition, aluminum, aluminum alloy, indium oxide, tin oxide, a plastic having a layer formed by vacuum deposition of an indium oxide-tin oxide alloy (for example, Polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluorinated ethylene, etc., conductive particles (eg,
Aluminum powder, titanium oxide, tin oxide, zinc oxide, carbon black, silver particles, etc.) with a suitable binder, or a substrate coated on the above conductive substrate, a substrate or conductive material impregnated with plastic or paper. It is possible to use a plastic or the like having a hydrophilic polymer.

An undercoat layer having a barrier function and an adhesive function can be provided between the conductive layer and the photosensitive layer. The undercoat layer is casein,
Polyvinyl alcohol, nitrocellulose, ethylene-
It can be formed of acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin, aluminum oxide and the like.

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

In the case of using a photoreceptor in which a conductive layer, a charge generation layer and a charge transport layer are laminated in this order, since the compound has a hole transport property, it is necessary to negatively charge the surface of the charge transport layer. In the exposed area, the holes generated in the charge generation layer are injected into the charge transport layer, and then reach the surface to neutralize the negative charges, the surface potential is attenuated, and electrostatic contrast is generated with the unexposed area. At the time of development, it is necessary to use a positively charged toner, contrary to the case of using an electron transport substance.

In another embodiment of the present invention, the above-mentioned disazo pigments or U.S. Pat.Nos. 3,554,745, 3,567,438 and 358,650.
Pyrylium dyes, thiapyrylium dyes, serenapyrylium dyes, benzopyrylium dyes, etc.
A photoconductive pigment or dye such as a benzothiapyrylium dye, a naphthopyrylium dye, or a naphthothiapyrylium dye can also be used as a sensitizer.

Further, in another specific example, 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, 4- [4
-Bis- (2-chloroethyl) aminophenyl] -2,6
-Diphenylthiapyrylium perchlorate and poly (4,
4'-isopropylidene diphenylene carbonate) is a halogenated hydrocarbon solvent (for example, dichloromethane,
Chloroform, carbon tetrachloride, 1,1-dichloroethane, 1,2
-Dichloroethane, 1,1,2-trichloroethane, chlorobenzene, bromobenzene, 1,2-dichlorobenzene)
In a non-polar solvent (e.g., hexane,
It is obtained as a particulate eutectic complex by adding octane, decane, 2,2,4-trimethylbenzene and ligroin. The electrophotographic photoreceptor in this 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 and the like can be contained as a binder.

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

According to the present invention, it is possible to provide a high-sensitivity electrophotographic photosensitive member, and there is an advantage that variations in the light portion potential and the dark portion potential upon repeated charging and exposure are small.

Hereinafter, the present invention will be described according to examples.

Example 1 Pigment 7 g obtained by refluxing β-type copper phthalocyanine (trade name Lionol Blue NCB Toner) manufactured by Toyo Ink Mfg. Co., Ltd. in water, ethanol and benzene in order, followed by filtration; Polyester adhesive 49,000
(Solid content 20%) ”14 g; toluene 35 g; dioxane 35 g were mixed and dispersed by a ball mill for 6 hours to prepare a coating liquid. This coating solution was applied onto an aluminum sheet with a Meyer bar so that the dry film thickness would be 0.5 μm, to form a charge generation layer.

Next, 7 g of the exemplified compound (5) as a charge transport compound
And 7 g of polycarbonate resin (trade name "Panlite K-1300" manufactured by Teijin Chemicals Ltd.) in tetrahydrofuran 35
The solution obtained by stirring and dissolving in a mixed solvent of g and 35 g of chlorobenzene was applied onto the above charge generation layer with a Meyer bar so that the dry film thickness would be 11 microns, and a photosensitive layer consisting of two layers was formed. An electrophotographic photoreceptor having layers was prepared.

The electrophotographic photoconductor thus prepared is manufactured by Kawaguchi Electric Co., Ltd.
Using an electrostatic copying paper tester Model-SP-428, corona charging was performed at -5 KV by a static method, held for 1 second in a dark place, and then exposed at an illuminance of 5 lux to examine charging characteristics.

The charging characteristics are as follows: the surface potential (V ₀ ) and the exposure amount (E1 / E1) required to attenuate the potential (V ₁ ) when dark decaying for 1 second to 1/2.
2) was measured.

Further, in order to measure the fluctuation of the light potential and the dark potential when repeatedly used, the photoconductor prepared in this example was attached to the cylinder for the photoconductive drum of the Canon PPC copier NP-150Z. , 50,000 copies were made with the same machine, and the light potential (V _L ) and the dark potential (V _D ) at the initial stage and after copying 50,000 sheets
The following structural formula was used instead of the exemplified compound. Comparative sample-1 by the completely same operation using the compound of
Was prepared and measured in the same manner.

The results are shown below.

Examples 2 to 16 In each of these Examples, the charge transporting compound used in Example 1 was replaced with the exemplified compound (1), (3), (4), (6), (). 7), (9),
(11), (12), (13), (18), (21), (22),
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that (23), (30) and (31) were used and the pigment of Example (16) was used as the charge generating substance.

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 22.2 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 charge generating substance of Ex. No. 25, 1 part by weight of butyral resin (Eslek BM-2: manufactured by Sekisui Chemical Co., Ltd.) and 30 parts by weight of isopropyl alcohol were dispersed for 4 hours by a ball mill disperser. This dispersion was applied onto the previously formed subbing layer by a dip coating method and dried to form a charge generation layer. The film thickness at this time was 0.3 micron.

Next, 1 part by weight of the compound No. (2) according to the present invention exemplified above, 1 part by weight of a polysulfone resin (P1700: manufactured by Union Carbide Co.) and 6 parts by weight of monochlorobenzene were mixed and stirred and dissolved by a stirrer. . This liquid was applied onto the charge generation layer by a dip coating method and dried to form a charge transport layer. The film thickness at this time was 12 microns.

Corona discharge of -5 KV was applied to the thus prepared photoreceptor. The surface potential at this time was measured (initial potential V ₀ ). Further, the surface potential of the photoconductor after being left in the dark for 5 seconds was measured (attenuation). Sensitivity is the potential V _K after dark decay is 1 /
Exposure required to attenuate to 2 (E1 / 2 microJules / c
It was evaluated by measuring m ² ). At this time, a ternary semiconductor laser of gallium / aluminum / arsenic (output: 5 mW, oscillation wavelength 780 nm) was used as a light source. These results were as follows.

V ₀ : −680 V Potential holding ratio: 94% E1 / 2: 1.0 microjoule / cm ² Next, the above photoconductor is used as a photoconductor of LBP-CX in a laser beam printer (LBP-CX manufactured by Canon Inc.), which is an electrophotographic printer of reversal development system equipped with the same semiconductor laser. Was replaced and set, and an actual image forming test was conducted. The conditions are as follows.

Surface potential after primary charging: -700v, surface potential after image exposure;
-150V (exposure amount 1.2μJ / cm ² ), transfer potential; + 700V, developer polarity; negative polarity, process speed; 50mm / sec, development condition (development bias); -450V, image exposure scan method; image scan, primary Pre-charging exposure: 50 lux · sec red full surface exposure, image formation was performed by line 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 exemplified compound (No. (8)) were mixed with polyester (Polyester Adhesive 49000: manufactured by Deupon Corporation). ) Was mixed with 100 ml of a toluene (50) -dioxane (50) solution and dispersed by a ball mill for 6 hours. This dispersion was applied onto an aluminum sheet with a Meyer bar so that the film thickness after drying would be 15 microns.

The electrophotographic characteristics of the photoconductor thus prepared are shown in Example 1.
It measured by the method similar to. The results are shown below.

V _0: -620 volt V _1: -610 volt E1 / 2: 1.6lux · sec initial V _D: -695 volts V _L: -70 volts 50,000 sheets endurance after V _D: -665 volts V _L: -105 volts implementation Example 19 Aqueous ammonia solution of casein (casein-1
1.2 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 micron.

Next, with a disazo pigment 5g having the following structure, 2 g of butyral resin (degree of butyralization: 63 mol%) was dispersed in a solution of 95 ml of ethanol and dispersed, and then applied onto the adhesive layer to form a charge generation layer having a thickness of 0.4 micron after drying.

Next, 5 g of the above-exemplified compound (No. (14)) and poly-4,
A solution of 5 g of 4'-dioxydiphenyl-2,2-propane carbonate (viscosity average molecular weight 30,000) in 150 ml of dichloromethane was applied on the charge generation layer and dried to form a charge transport layer with a thickness of 11 microns. By doing so, an electrophotographic photosensitive member was prepared.

The electrophotographic characteristics of the electrophotographic photosensitive member thus produced were measured in the same manner as in Example 1.

The results are shown below.

V ₀ : −605 volt V ₁ : −595 volt E1 / 2: 2.3 lux ・ sec Initial V _D : −705 volt _VL : −70 volt After running 50000 sheets V _D : −670 volt _VL : −100 volt Example 20 A 0.2 mm thick molybdenum plate (substrate) whose surface was cleaned was fixed at a predetermined position in a 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 with respect to hydrogen gas) were introduced into the tank, and the gas flow rate and the main valve of the vapor deposition 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 was grown on the substrate and kept under the same conditions until the film thickness became 2 μ, and then the glow discharge was stopped. After that, turn off the heater and high-frequency power supply, wait until the substrate temperature reaches 100 ° C, close the outflow valves for hydrogen gas and silane gas, temporarily set the inside of the tank to 10 ^-5 torr or less, and then return to atmospheric pressure. Took out. Then, as an example of a charge transport compound, a compound N was formed on the amorphous silicon layer.
A charge transport layer was formed in exactly the same manner as in Example 1 except that o.1 was used.

The photoconductor thus obtained was installed in the charging exposure experimental device.
It was corona charged at 6 KV 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 chargeable developer (including toner and 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 3 g of poly (4,4'-isopropylidene diphenylene carbonate) were sufficiently dissolved in 200 ml of dichloromethane. After that, 100 ml of toluene was added to precipitate the eutectic complex. After filtering this precipitate off,
Dichloromethane was added to redissolve it and then n
-Hexane 100 ml was added to obtain a eutectic complex precipitate.

5 g of this eutectic complex was added to 95 ml of a methanol solution containing 2 g of polyvinyl butyral and dispersed by a ball mill for 6 hours. This dispersion was applied on an aluminum plate having a casein layer by a Meyer bar so that the film thickness after drying would be 0.4 μm to form a charge generation layer.

Then, a coating layer for the charge transport layer was formed on the charge generation layer in exactly the same manner as in Example 1 except that the exemplified compound No. (25) 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 : −600 volt V ₁ : −590 volt E1 / 2: 1.9 lux ・ sec Initial V _D : −695 volt _VL : −75 volt After running 50000 sheets V _D : −660 volt _VL : −105 volt Example 22 5 g similar to the eutectic complex used in Example 21 and 5 g of the above-exemplified compound (No. (28)) were added to 150 ml of a tetrahydrofuran solution of polyester (Polyester Adhesive 49000: manufactured by Deupon), The mixture was thoroughly 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 below.

V ₀ : −590 volt V ₁ : −580 volt E1 / 2: 2.4lux ・ sec Initial V _D : −700 volt _VL : −60 volt After running 50000 sheets V _D : −660 volt _VL : −95 volt EFFECTS OF THE INVENTION As described above, the electrophotographic photosensitive member according to the present invention has high sensitivity, and in particular, has excellent characteristics of potential stability in continuous image formation in which repeated charging and exposure are performed.

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Norihiro Kikuchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Masakazu Matsumoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (56) Reference JP-A-60-254139 (JP, A) JP-A-61-53647 (JP, A) JP-A-52-4242 (JP, A)

Claims (1)

[Claims] 1. An electrophotographic photosensitive member having a layer containing a compound represented by the following general formula. General formula (In the formula, R ₁ represents an alkyl group which may have a substituent or an aralkyl group, and R ₂ , R ₃ , R ₄ and R ₅ may be an alkyl group which may have a substituent, an aralkyl group or an aryl group. A group or a heterocyclic group, R ₂ and R ₃ or R ₄ and R ₅ may be bonded to form a 5- or 6-membered ring together with the nitrogen atom in the formula, and X ₁ and X ₂ are hydrogen atoms. ,
Halogen atom, alkyl group, alkoxy group, nitro group,
A cyano group and a trifluoromethyl group are shown. )