JPH0789225B2 - 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 charge dissipation in the dark, or being able to rapidly dissipate charges by light irradiation. 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.
Further, hydrazone compounds disclosed in U.S. Pat.No. 4,150,987, triarylpyrazoline compounds described in U.S. Pat.No. 3837851, 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 sensitivity and the characteristics are not necessarily sufficient in the electrophotographic photoreceptor using the conventional low molecular weight organic photoconductor for the charge transport layer, and in particular, repeated charging and exposure are performed. In that case, there is a point that the fluctuations in the light potential and the dark potential should be greatly improved.

[Problems to be solved by the invention]

An object of the present invention is to provide an electrophotographic photosensitive member which 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]

The object of the present invention is achieved by an electrophotographic photoreceptor having a photosensitive layer containing a compound represented by the following general formula (1).

General formula (1) However, in the formula, R ₁ , R ₂ , R ₃ and R ₄ are optionally substituted alkyl groups such as methyl, ethyl, propyl and butyl, or optionally substituted benzyl, phenethyl, naphthylmethyl An aralkyl group such as anthrylmethyl or an optionally substituted phenyl, naphthyl, anthryl, phenanthryl or another aryl group or an optionally substituted pyridyl, quinolyl, thienyl, furyl, oxazolyl, thiazolyl, triazolyl And heterocyclic groups such as imidazolyl and carbazolyl. R ₁ , R ₂ or R ₃ , R ₄ is N
The residue which forms a 5- or 6-membered ring with an atom is shown. here
R ₁ , R ₂ , R ₃ and R ₄ may be the same or different. Further, as the substituents of R ₁ , R ₂ , R ₃ and R ₄ , alkyl groups such as methyl, ethyl and propyl, alkoxy groups such as methoxy, ethoxy and propoxy, fluorine,
Halogen atom such as chlorine and bromine, nitro group, cyano group, phenyl, naphthyl, aromatic ring such as anthryl, pyridyl,
Heterocyclic groups such as quinolyl, furyl and thienyl can be mentioned.

In the formula, A is naphthalene, anthracene, phenanthrene,
A divalent group formed by removing two hydrogen atoms from one selected from pyrene, fluorene, fluorenone, pyridine, pyrazine, naphthyridine, carbazole, phenoxazine and phenothiazine is shown, and may have a substituent. . As a substituent which A has, an alkyl group such as methyl, ethyl and propyl, an alkoxy group such as methoxy, ethoxy and propoxy, a halogen atom such as fluorine, chlorine and bromine,
Examples thereof include nitro group, cyano group, aryl group such as phenyl and naphthyl.

Typical examples of the compound represented by the general formula (1) will be given below.

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

Synthesis Example 1 1,5-bis (p-aminophenyl) naphthalene 5.00 g (1
6.1mmole) in 100 ml of anhydrous tetrahydrofuran,
3.87 g (9% of oily sodium hydride (content 60%) under ice cooling stirring
6.8 mmole) is added slowly. After the addition is complete, stir for 30 minutes at room temperature. Then ethyl iodide 7.74 ml (96.8 mmole)
Is slowly added dropwise, and after completion of the addition, the mixture is stirred at room temperature for 1 hour and further stirred at reflux for 8 hours. After completion of the reaction, add about 50
Pour into 0 ml, extract with 300 ml of ethyl acetate, wash the organic layer with water, dry with sodium sulfate, and dry under reduced pressure to give 1,5-bis (p-diethylaminophenyl) naphthalene (Compound Example No. (2)).
Obtained 5.30 g. The yield was 77.8%.

Elemental analysis Calculated value (%) Experimental value (%) C 85.26 85.19 H 8.11 8.18 N 6.63 6.61 Synthesis example 2 1- (p-aminophenyl) obtained by partial reduction of 1,5-bis (p-nitrophenyl) naphthalene -5- (p-nitrophenyl) naphthalene 3.00g (8.81mmole), iodobenzene 20.84g (102mmole), copper powder 0.68g, potassium carbonate
2.84g (20.5mmole) is put into a 50ml eggplant flask, and the mixture is refluxed and stirred for 20 hours. After completion of the reaction, the reaction product is poured into 100 ml of water and extracted with ethyl acetate. The organic layer is washed with water, dried over sodium sulfate and dried under reduced pressure. Isopropyl ether was added to the residue to precipitate 1- (p-diphenylaminophenyl) -5- (p
Crystals of -nitrophenyl) naphthalene are taken. yield
2.75 g Yield 63.4% 1- (p-Diphenylaminophenyl) -5- (p-nitrophenyl) naphthalene obtained by reducing 1- (p-diaminophenyl) -5- (p-diphenylaminophenyl) naphthalene 2.00 g (4.32 mmole) was ethylated in the same manner as in Synthesis Example 1 to give 1- (p-diethylaminophenyl).
1.80 g of -5- (p-diphenylaminophenyl) naphthalene (Compound Example No. (5)) was obtained. Yield 80.3% Elemental analysis Calculated value (%) Experimental value (%) C 87.99 87.85 H 6.61 6.68 N 5.40 5.46 Compounds other than the synthesis examples are generally synthesized in the same manner as above.

In a preferred embodiment of the electrophotographic photoreceptor according to the present invention,
The compound represented by the above general formula (1) 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 charge transport compound represented by the general formula (1) and a binder in a suitable solvent and drying. 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,
Examples thereof include polycarbonate, polyurethane, and copolymer resins containing two or more of repeating units of these resins, such as styrene-butadiene copolymer, styrene-acrylonitrile copolymer, and styrene-maleic acid copolymer. 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 charge transport compound of the present invention is 10 to 500 parts by weight of the compound of the present invention per 100 parts by weight of the binder.
Weight is preferable.

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 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 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 is a dip coating method, a spray coating method, a spinner coating method, a bead coating method,
The coating can be performed using a coating method such as a Mayer 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. The heat drying can be carried out at a temperature of 30 ° C. to 200 ° C. for a time in the range of 5 minutes to 2 hours while still or under blowing air.

The charge transport layer of the present invention may contain various additives. Examples of such additives include diphenyl, diphenyl chloride, O-ta-phenyl, P-ta-phenyl, dibutyl phthalate, dimethyl glycol phthalate, dioctyl phthalate, triphenyl phosphoric acid, methylnaphthalene, benzophenone, chlorinated paraffin, and dilauryl thiopropyl. Examples thereof include pionate, 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,
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 in the 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 conductor as possible to obtain sufficient absorbance, and in order to shorten the range of the generated charge carriers, a thin film layer, for example, 5 microns or less, preferably A thin film layer having a film thickness of 0.01 to 1 micron is preferable. 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 trapping (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, a plastic having a layer in which aluminum, an aluminum alloy, indium oxide, tin oxide, an indium oxide-tin oxide alloy, or the like is formed by a vacuum evaporation method (for example, Polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluoroethylene, etc.), conductive particles (for example,
Aluminum powder, titanium oxide, tin oxide, zinc oxide, carbon black, silver particles, etc.) coated with a suitable binder on plastic or the above conductive substrate, a substrate or conductive material in which plastic particles or paper are impregnated with conductive particles. It is possible to use a plastic 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,
It can be formed from polyvinyl aluminum, nitrocellulose, ethylene-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 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, the compound of the present invention has a hole transport property, and therefore the surface of the charge transport layer needs to be negatively charged. When exposed, holes generated in the charge generation layer in the exposed area are injected into the charge transport layer, neutralize the negative charges reaching the surface after that, and the surface potential is attenuated, resulting in an electrostatic contrast with the unexposed area. Occurs. 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,
Octane, decane, 2,2,4-trimethylbenzene, ligroin) is added to obtain a particulate eutectic complex. The electrophotographic photoreceptor in this example includes styrene-butadiene polymer, 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 fluctuations in the light portion potential and the dark portion potential upon repeated charging and exposure are small.

〔Example〕

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

Example 1 β-type copper phthalocyanine (manufactured by Toyo Ink Mfg. Co., Ltd., trade name Lionol Blue NCB Toner) was sequentially refluxed in water, ethanol and benzene, and then purified through filtration to obtain 7 g of 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 (26) was used 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 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.) and held in a dark place for 1 second. After that, it was exposed to an illuminance of 25 lux and the charging characteristics were examined.

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.

In addition, in order to measure the fluctuation of the light potential and the dark potential when repeatedly used, the photoconductor prepared in this example
Stick it on the cylinder for the photoconductor drum of a copier (NP-150Z made by Canon Inc.) and make 50,000 copies with the same machine.
Bright area potential (V _L ) and dark area potential (V _L ) at the initial stage and after copying 50,000 sheets
The variation of _D ) was measured.

Further, instead of the exemplified compound (26), the following structural formula 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.

From these results, the electrophotographic photoreceptor using the compound of the present invention in the charge transport layer is superior in sensitivity and characteristics to the electrophotographic photoreceptor using the conventional organic photoconductor, and particularly excellent in repeated charging characteristics. It turned out that

Examples 2 to 16 In each of the examples, the example compound No. 5 was used instead of the example compound (5) as the charge transport compound used in the example 1.
(1), (2), (4), (7), (10), (11),
(13), (16), (18), (21), (24), (30),
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that (33), (34) and (48) were used and the pigment of Example (44) 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 3 g of 4- (4-dimethylaminophenyl) -2,6-diphenylthiapyrylium perchlorate and 5 g of the above exemplified compound (2) were used as polyester (polyester adhesive 49).
000: manufactured by DuPont) toluene (50) -dioxane (5
0) 100 ml of the solution was mixed and dispersed with 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 : −680 V V ₁ : −650 V E1 / 2: 2.5 lux ° sec Initial V _D : −690 V _VL : −130 V After 50000 sheets endurance V _D : −670 V V _L : −150 V Implemented Example 18 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, a liquid prepared by dissolving 5 g of the above-exemplified compound (12) and 5 g of poly-4,4'-dioxydiphenyl-2,2'-propane carbonate (viscosity average molecular weight 30000) in 150 ml of dichloromethane was placed on the charge generation layer. An electrophotographic photosensitive member was prepared by coating and drying the above, and forming a charge transport layer having a film thickness of 11 μm.

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 : −680 volt V ₁ : −640 volt E1 / 2: 3.8 lux ° sec Initial V _D : −700 volt _VL : −190 volt After running 50000 sheets V _D : −680 volt _VL : −210 volt Implemented Example 19 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, the same conditions were maintained until the film thickness became 2 μ, and then glow discharge was stopped. After that, turn on the heater and high-frequency power supply in the Nef state, wait until the substrate temperature reaches 100 ° C, close the outflow valves of 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. Next, a charge transport layer was formed on this amorphous silicon layer in exactly the same manner as in Example 1 except that the exemplified compound (5) was used as the charge transport compound.

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 20 An aqueous ammonia solution of casein (11.2 g of casein, 1 g of 28% ammonia water, 222 ml of water) was applied onto an aluminum cylinder by a dip coating method, and dried to give a coating amount of 1.0 g / m ^2.
An undercoat layer was formed.

Next, 1 part by weight of the charge generating substance of No. 81, 1 part by weight of butyral resin (S-REC 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 the above-exemplified compound No. (2), 1 part by weight of polysulfone resin (P1700: manufactured by Union Carbide Co.) and 6 parts by weight of monochlorobenzene were mixed and stirred and welded 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 flow surface potential at this time was measured (initial potential V ₀ ). Further, the surface potential of this photoconductor after being left in the dark for 5 seconds was measured (attenuation). Sensitivity is the potential V _K after dark decay
It was evaluated by measuring the amount of exposure (E1 / 2 microjoule / cm ² ) required to attenuate 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. These results were as follows.

V ₀ : −690 bolt E1 / 2: 2.5 microjoules / cm ² Next, the above photoconductor is used as a photoconductor of LBP-CX in a laser beam printer (LBP-CX made by Canon) which is an electrophotographic printer of reversal development system equipped with the same semiconductor laser. Was set and replaced with, and an actual image forming test was performed.
The conditions are as follows.

Surface potential after primary charging: -700V, surface potential after image exposure;
-150 V (exposure quantity 1.2 J / cm ^2), transfer potential; + 700 V, the developer polarity; negative process speed: 50 mm / sec, the developing condition (developing bias); - 450V, image exposure scanning system; image scanning, primary Pre-charging exposure: 50 lux · sec red full-area 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 21 4- (4-Dimethylaminophenyl) -2,6-diphenylthiapyrylium perchlorate 3 g and poly (4,4'-isopropylidene diphenylene carbonate) 3 g were sufficiently dissolved in 200 ml of dichloromethane, 100 ml of toluene was added to precipitate the eutectic complex. After separating this precipitate,
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, when the exemplified compound (26) was used on this charge generation layer, a coating layer for the charge transport layer was formed in exactly the same manner as in Example 1.

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 : −710 volt V ₁ : −680 volt E1 / 2: 3.5lux ・ sec Initial V _D : −690 volt V _L : −180 volt After 5000 cycles of durability V _D : −670 volt V _L : −210 volt Example 22 5 g of the same eutectic complex used in Example 20 and 5 g of the above-exemplified compound (52) were added to a tetrahydrofuran solution (150 m) of polyester (Polyester Adhesive 49000: manufactured by DuPont).
In addition to 1, 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 : −670 Volt V ₁ : −650 Volt E1 / 2: 2.7lux ・ sec Initial V _D : −700 Volt V _L : −130 Volt After Endurance of 50000 Sheets V _D : −680 Volt V _L : −140 Volt EFFECTS OF THE INVENTION As is apparent from the above, according to the present invention, by containing a specific low molecular weight organic compound in the photosensitive layer, the sensitivity characteristics are excellent, and the light potential and dark area potential after repeated charging / exposure use are increased. It is possible to provide an unprecedented excellent electrophotographic photoreceptor with improved fluctuation.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technology display location G03G 5/06 316 Z 318 A (72) Inventor Masashige Ubara Hara 3-30 Shimomaruko, Ota-ku, Tokyo No. 2 Canon Inc. (72) Inventor Masakazu Matsumoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Inc. Canon Inc. (56) Reference JP-A-60-19146 (JP, A) JP-A-54 -61936 (JP, A)

Claims (2)

[Claims] 1. A general formula (I) _{(Wherein, R 1, R 2, R} 3, R 4 is an optionally substituted alkyl group, an aralkyl group, an aryl group, a heterocyclic group, each of which may be the same .R ₁ And R ₂ or R ₃ and R ₄ may form a ring together with a nitrogen atom, A is naphthalene, anthracene, phenanthrene, pyrene, fluorene, fluorenone, pyridine, pyrazine, naphthyridine, carbazole, phenoxazine, phenothiazine. An electrophotography having a photosensitive layer containing a compound represented by a divalent group formed by removing two hydrogen atoms from a group selected from the group represented by the formula (1) and optionally having a substituent. Photoconductor. 2. The photosensitive layer is a function-separated type comprising a charge generation layer and a charge transport layer, and the charge transport layer contains the compound represented by the general formula (I).
The electrophotographic photosensitive member according to the item.