JP2501198B2 - 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.

[Conventional technology]

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 a number of advantages, such as being able to be charged to a proper potential in the dark, having little dissipation of charges in the dark, or being able to dissipate charges rapidly by irradiation with light. On the other hand, it 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 do not provide stable sensitivity in humid environments, and zinc oxide-based photoconductors require the sensitizing effect of sensitizing dyes typified 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. In addition, 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 and the like. Low molecular weight organic photoconductors such as the described 9-styrylanthracene compounds have been 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.

On the other hand, in recent years, a laminated structure has been proposed in which a photosensitive layer is functionally separated into a charge generation layer and a charge transport layer. The electrophotographic photosensitive member having the laminated structure as a photosensitive layer has a sensitivity to visible light,
It has become possible to improve the charge retention and surface strength. Such an electrophotographic photoreceptor is disclosed in, for example, US Pat.
No. 851, No. 3871882, and the like.

However, even in this laminated structure, the conventional electrophotographic photoreceptor using a low molecular weight organic photoconductor as the charge transport layer,
Sensitivity and characteristics are not always sufficient, and there is a point that the fluctuations in the bright portion potential and the dark portion potential should be greatly improved when repeatedly charged and exposed.

[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 has the general formula (I): (Where X is -O-, -S-, _{-CH 2 -CH 2 -, - CH} = CH-, Or -N = N-, and R ₁ , R ₂ , R ₃ and R ₄ are substituted or unsubstituted alkyl groups, aralkyl groups, aryl groups, heterocyclic groups or R ₁ and R ₂ , R ₃ and R ₄ Represents a residue forming a 5- or 6-membered ring with a nitrogen atom. However, R ₁ , R ₂ , R ₃ , and R ₄ may be the same or different. ) An electrophotographic photoreceptor having a layer containing a compound represented by: In the formula, R _{1 to} R ₄ may be the same or different, substituted or unsubstituted methyl, ethyl, propyl, an alkyl group such as butyl, benzyl, phenethyl, an aralkyl group such as naphthylmethyl, phenyl,
An aryl group such as diphenyl, naphthyl, anthony, fluorenyl, etc., a heterocyclic group such as thienyl, furyl, benzoxazolyl, benzothiazolyl, pyridyl, quinolyl, carbazolyl, or R ₁ and R ₂ , R ₃ and R ₄ And represent a residue forming a 5- or 6-membered heterocyclic group such as substituted or unsubstituted benzoxazolyl, benzothiazolyl, piperidyl, monophoryl, carbezolyl together with a nitrogen atom.

As the substituent of the group represented by R _{1 to} R ₄ , a hydroxyl group,
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 groups, aryl groups such as phenyl, diphenyl and naphthyl,
Aryloxy group such as phenyloxy, amino group, dimethylamino, diethylamino, diphenylamino, ditolylamino, substituted amino group such as dianisylamino, pyrrolidino, piperidino, monofolino, nitro group, trifluoromethyl group, cyano group, acetyl group, An acyl group such as a benzoyl group can be used.

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

Compound example Next, representative synthetic examples of the above compounds will be shown.

Synthesis Example 1 Compound (a) shown below 5.00 g (25.3 mmol) was dissolved in 100 ml of anhydrous tetrahydrofuran and oily sodium hydride (content 60%) was added with stirring under ice-water cooling.
6.06 g (151.5 mmol) are added slowly. After addition 30
Stir for minutes at room temperature. After that, 12.11 ml of ethyl iodide (1
(51.5 mmol) is slowly added dropwise, and after completion of the addition, the mixture is stirred at room temperature for 1 hour, and further refluxed for 8 hours. After completion of the reaction, the reaction product was poured into about 500 ml of ice water and extracted with 300 ml of ethyl acetate. The organic layer was washed with water, dried over sodium sulfate and dried under reduced pressure to obtain 5.89 g of the compound shown below (Compound Example No. 2).

The yield was 75.2%.

Elemental analysis Calculated value (%) Measured value (%) C 77.42 77.38 H 8.39 8.33 N 9.03 9.00 Compounds other than the synthesis examples are generally synthesized in the same manner as above.

In a preferred specific example of the electrophotographic photosensitive member according to the present invention, a compound represented by the general formula (I) is used as a charge transporting substance of an electrophotographic photosensitive member having a photosensitive layer functionally separated into a charge generating layer and a charge transporting layer. You can

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. As the binder used here, for example, 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, polycarbonate, polyurethane or a copolymer resin containing two or more repeating units of these resins, for example, styrene-butadiene copolymer, styrene-acrylonitrile. Copolymers, styrene-maleic acid copolymers and the like can be mentioned. In addition to such insulating polymers, organic photoconductive polymers such as polyvinylcarbazole, polyvinylanthracene and polyvinylpyrene can also be used.

The mixing ratio of the binder and the compound is 100
The amount of the compound is preferably 10 to 500 parts by weight per 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 thereunder. 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, 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 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. 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, sulfoxides such as dimethyl sulfoxide, tetrahydrofuran, dioxane, ethylene glycol monomethyl Ethers such as ethers, 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, ligroin, monochloro Aromatic compounds such as benzene 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 performed by touch drying at room temperature and then heating and drying. Heat drying is performed at a temperature of 30 to 200 ° C for 5 minutes to 2 hours.
It can be performed at rest or under blast for a time in the time range.

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,
Examples thereof include dioctyl phthalate, triphenyl phosphoric acid, methylnaphthalene, benzophenone, chlorinated paraffin, dilauryl thiopropionate, 3,5-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 a charge generating substance such as quinocyanine or 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 (58) Squaric acid methine dye (59) Indico dye (CINo.78000) (60) Thioindico dye (CINo.78800) (61) β-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, polyacrylamide resin, polyamide, polyvinyl pyridine, cellulosic resin, urethane resin Insulating resins such as epoxy resin, casein, polyvinyl alcohol, and polyvinylpyrrolidone. The resin contained in the charge generation layer is 80% by weight or less, preferably
Suitable below 40% by weight. As the organic solvent used at the time of coating, methanol, ethanol, alcohols such as isopropanol, acetone, methyl ethyl ketone,
Ketones such as cyclohexanone, N, N-dimethylformamide, amides such as N, N-dimethylacetamide, sulfoxides such as dimethylsulfoxide, ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, methyl acetate, ethyl acetate, etc. Ester, chloroform, methylene chloride,
Aliphatic halogenated hydrocarbons such as dichloroethylene, carbon tetrachloride and trichloroethylene, or benzene, toluene, xylene, ligroin, monochlorobenzene,
Aromatic substances such as 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.

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 carriers, a thin film layer such as 5
It is preferable to use a thin film layer having a film thickness of not more than micron, preferably 0.01 micron to 1 micron. This is
Most of the amount of incident light is absorbed by the charge generation layer to generate many charge carriers, and the generated charge carriers need to be injected into the charge transport layer without being deactivated by recombination or trapping. Is attributed to

The photosensitive layer having such a laminated structure of the charge generation layer and the charge transport layer is provided on a substrate having a conductive layer. As the substrate having a conductive layer, a substrate having conductivity, for example, aluminum, an aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold, platinum, or the like can be used. , Other aluminum, aluminum alloy,
A plastic having a layer formed by vacuum deposition of indium oxide, tin oxide, an indium oxide-tin oxide alloy, or the like (for example, polyethylene, polypropylene,
Polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluorinated ethylene, etc.), conductive particles (eg, carbon black, silver particles, etc.) coated on plastic with a suitable binder, conductive particles on plastic or paper An impregnated substrate or a plastic having a conductive polymer can be used.

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, copolymer nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin, aluminum oxide, etc. it can.

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

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, the charge transport layer surface needs to be negatively charged. 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 where an electron transport material is used.

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.

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) are converted to halogenated hydrocarbon solvents (for example, dichloromethane, chloroform, carbon tetrachloride, 1,1-dichloroethane, 1,1-dichloroethane). 2-dichloroethane, 1,1,2-trichloroethane,
After dissolving in chlorobenzene, bromobenzene, 1,2-dichlorobenzene), a non-polar solvent (e.g., hexane, octane, decane, 2,2,4-trimethylbenzene, ligroin) is added to the particulate co-solvent. And a styrene-butadiene copolymer, a silicone resin,
Containing vinyl resin, vinylidene chloride-acrylonitrile copolymer, styrene-acrylonitrile copolymer, vinyl acetate-vinyl chloride copolymer, polyvinyl butyral, polymethyl methacrylate, poly-N-butyl methacrylate, polyesters, cellulose esters, etc. as a binder. Can be.

The electrophotographic photoreceptor of the present invention is used not only for electrophotographic copying machines, but also for laser printers, CRT printers,
It can be widely used in electrophotographic application fields such as 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〕

Example 1 β-type copper phthalocyanine (trade name Lionol Blue NCB Toner manufactured by Toyo Ink Mfg. Co., Ltd.) was sequentially refluxed in water, ethanol and benzene, and was then purified by passing through 7 g of a pigment; 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 above exemplified compound No. 2 as a charge transport compound
35 g of tetrahydrofuran with 7 g of polycarbonate resin (trade name "Panlite K-1300" manufactured by Teijin Chemicals Ltd.)
A solution obtained by stirring and dissolving it in a mixed solvent of 35 g of chlorobenzene and chlorobenzene was applied on the above charge generation layer with a Meyer bar so that the dry film thickness would be 11 μm. An electrophotographic photosensitive member having

The electrophotographic photosensitive member produced in this manner was used in an electrostatic copying paper tester manufactured by Denki Co., Ltd. (Model-SP-428 manufactured by Kawaguchi Electric Co., Ltd.)
Was used to statically corona-charge at −5 kV, hold it in the dark for 1 second, and then expose it at an illuminance of 5 lux to examine the charging characteristics.

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.

Further, in order to measure the fluctuation of the light potential and the dark potential when repeatedly used, the photoconductor prepared in this example is PP
C Copier (NP-150Z made by Canon Inc.) was attached to the cylinder for the photosensitive drum and 50,000 copies were made with the same machine, and the light potential (V _L ) and dark potential (V _D ) at the initial and after 50,000 copies were made. ) Was measured.

Further, instead of the exemplified compound No. 2, the following structural formula Comparative sample-
1 was prepared and measured in the same manner.

 The results are shown below.

From the results of this table, flatness is maintained at X in the general formula,
As a result, it can be seen that the transfer of electrons in the charge transport layer is facilitated and good characteristics are exhibited.

Examples 2 to 16 In each of these Examples, the exemplary compound N was used instead of the exemplary compound No. 2 as the charge transport compound used in Example 1 above.
o.5,8,12,13,20,22,25,27,32,34,39,41,47,55,59 and except that the pigment of the example (16) is used as the charge generating substance An electrophotographic photosensitive member was prepared in the same manner as in Example 1.

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

Example 17 3 g of 4- (4-dimethylaminophenyl) -2,6-diphenylthiapyrylium perchlorate and 5 g of the exemplified compound (No. 8) were added to toluene of polyester (Polyester Adhesive 49000: manufactured by DuPont). This was mixed with 100 ml of a (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 thus prepared photoconductor were measured by the same method as in Example 1. The results are shown below.

V ₀ : −635 Volt V ₁ :: −610 Volt E _{1 ] 2} : 2.5lux ・ sec Initial V _D : −625 Volt V _L : −95 Volt After 50,000 sheets endurance V _D : −610 Volt V _L : −120 Volt Example 18 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 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. 12) and poly-4,4 '
-Dioxydiphenyl-2,2-propanecarbonate (viscosity average molecular weight 30,000) 5g dissolved in 150ml dichloromethane was applied on the charge generation layer and dried to form a charge transport layer with a thickness of 11 microns. An electrophotographic photoreceptor was created.

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 : −635 bolts V ₁ :: −605 bolts E _{1 ] 2} : 2.2 lux ° sec Initial V _D : −645 bolts V _L : −75 bolts After 50,000 sheets endurance V _D : −610 volts V _L : −105 bolts Example 19 0.2 mm thick molybdenum plate (substrate) whose surface is cleaned
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 is increased to raise the molybdenum substrate temperature to 150 ° C.
Stabilized to. 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 is grown on the substrate and the film thickness is 2μ.
The glow discharge was stopped after maintaining the same conditions until. After that, turn off the heater and high frequency power supply,
After waiting for the 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 the substrate was returned to atmospheric pressure and the substrate was taken out. Next, on the amorphous silicon layer, exemplified compound No. 2 as a charge transport compound
A charge transport layer was formed in exactly the same manner as in Example 1 except that 0 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 photoreceptor to obtain a good toner image on the surface of the photoreceptor.

Example 20 4- (4-Dimethylaminophenyl) -2,6-diphenylthiapyrylium perchlorate 3 g and poly (4,4'-
After sufficiently dissolving 3 g of isopropylidenediphenylene carbonate in 200 ml of dichloromethane, 100 ml of toluene was added to precipitate a eutectic complex. After separating this precipitate, it was redissolved by adding dichloromethane, 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 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 this charge generation layer in exactly the same manner as in Example 1 except that Exemplified Compound No. 62 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 : −635 Volt V ₁ :: −605 Volt E _{1 ] 2} : 3.1lux ° sec Initial V _D : −645 Volt V _L : −100 Volt After Endurance of 50,000 Sheets V _D : −610 Volt V _L : −125 Volt Example 21 5 g of the same eutectic complex used in Example 20 and 5 g of the above-exemplified compound (No. 70) were added to 150 ml of a tetrahydrofuran solution of polyester (Polyester Adhesive 49000: manufactured by DuPont), and mixed well. And mixed and stirred. The film thickness after drying this solution on an aluminum sheet with a Meyer bar
It was applied so as to be 15μ.

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

V ₀ : −650 Volt V ₁ : −630 Volt E _{1 ] 2} : 3.2lux ・ sec Initial V _D : −635 Volt V _L : −110 Volt After 50,000 sheets endurance V _D : −605 Volt V _L : −135 Volt Example 22 Aqueous ammonia solution of casein on aluminum cylinder (casein 11.2 g, 28% ammonia water 1 g, water 22.2 m
l) is applied by the dip coating method, dried and the applied amount is 1.0
An undercoat layer of g / m ² was formed.

Next, 1 part by weight of the charge generating substance of Ex. No. 89, 1 part by weight of butyral resin (Eslec BM-2: manufactured by Sekisui Chemical Co., Ltd.) and 30 parts by weight of isopropyl alcohol were dispersed by a ball mill disperser for 4 hours. 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 Compound No. 32 of the present invention exemplified above, polysulfone resin (P1700: manufactured by Union Carbide Co., Ltd.), 1
Part by weight and 6 parts by weight of monochlorobenzene were mixed and dissolved by stirring with 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 this photoreceptor was measured after leaving it in the dark for 5 seconds. Sensitivity is the amount of exposure required to reduce the potential V _K after dark decay to 1/2 (E _{1 ] 2} microjoules / cm ² )
Was evaluated by measuring. 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 were as follows.

V ₀ : -705 V Potential holding ratio: 95% E _1/2 : 1.25 microjoule / cm ² Next, the above photoconductor was exposed to LBP-CX by a laser beam printer (LBP-CX manufactured by Canon Inc.), which is an electrophotographic printer of reversal development method equipped with the same semiconductor laser. It was replaced with the body and set, and an actual image forming test was performed.
The conditions are as follows.

Surface potential after primary charging: -700 V, surface potential after image exposure: -150 V (exposure amount 25 μJ / 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 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.

〔The invention's effect〕

As is clear from the above, according to the present invention, by incorporating a specific low molecular weight organic compound in the photosensitive layer, the sensitivity characteristics are excellent and the fluctuations of the light potential and the dark potential after the repeated charging exposure are used are improved. It is possible to provide an excellent electrophotographic photosensitive member that does not exist.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norihiro Kikuchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Gen Miyazaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Within the corporation (56) References JP-A-56-22437 (JP, A) JP-A-62-208054 (JP, A)

Claims (2)

(57) [Claims] 1. General formula (I): (Where X is -O-, -S-, _{-CH 2 -CH 2 -, - CH} = CH-, Or -N = N-, and R ₁ , R ₂ , R ₃ and R ₄ are substituted or unsubstituted alkyl groups, aralkyl groups, aryl groups, heterocyclic groups or R ₁ and R ₂ , R ₃ and R ₄ Represents a residue forming a 5- or 6-membered ring with a nitrogen atom. However, R ₁ , R ₂ , R ₃ , and R ₄ may be the same or different. ) An electrophotographic photoreceptor having a layer containing a compound represented by: 2. The above-mentioned layer is a function-separated type comprising a charge generation layer and a charge transport layer, and the charge transport layer has the above general formula (I).
The electrophotographic photosensitive member according to claim 1, which contains a compound represented by: