JPH0293466A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the sensitivity and durability of the photosensitive body by providing a layer contg. a specific dibenzodiazine as a charge transfer material to the photosensitive body. CONSTITUTION:The layer contg. the dibenzodiazine expressed by the formula I is provided. In the formula, R1 to R4 denote H, alkyl or alkoxy. For example, a liquid dispersion prepd. by dispersing a phthalocyanine pigment into a polyester soln. is applied on an Al sheet to form a charge generating layer an a soln. prepd. by dissolving the above-mentioned compd. (e.g. the compd. expressed by the formula II) into a polycarbonate soln. is applied thereon to form a charge transfer layer.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to electrophotographic photoreceptors, and more particularly to electrophotographic photoreceptors containing low molecular weight organic photoconductors that provide improved electrophotographic properties.

[Prior Art] Conventionally, photoconductive materials used in electrophotographic photoreceptors include:
Selenium, cadmium sulfide1. Inorganic light such as zinc diluted J#
Amanosei material Ne1 is known. These photoconductive materials have a number of advantages, such as being able to be charged to an appropriate potential in the dark, and having little charge dissipation in the dark or light! ! <Although it has the advantage of being able to quickly dissipate charge by radiation, it has various drawbacks. For example, selenium-based photoreceptors easily crystallize due to factors such as temperature, humidity, dust, and pressure. progresses.

In particular, when the ambient temperature exceeds 40'O, crystallization becomes significant, resulting in drawbacks such as a decrease in chargeability and the appearance of white In dots in images. Cadmium sulfide photoreceptor is a humid ring 1.
Stable sensitivity cannot be obtained below 11.

Oxidation I++: Lead-based photoreceptors require the sensitizing effect of sensitizing dyes such as rosebental, but these sensitizing dyes cause charge deterioration due to corona charging and photobleaching due to exposure light, so long-term sensitization is required. The drawback is that it is not possible to change stable images.

Various organic photoconductive polymers have been proposed, including polyvinyl carpasol, but these polymers are superior to inorganic photoconductive materials in terms of film formability, light weight, and uniformity. Despite this, it has been difficult to put it into practical use until now. This is because they have not yet been able to obtain sufficient growth properties and are inferior to inorganic photoconductive materials in terms of sensitivity, durability, and stability against environmental changes.

Also, hydrazone compounds described in US Pat. No. 4,150,987, triarylpyrazoline compounds described in US Pat. No. 3,837,851, etc.,
Low-molecular organic photoconductors such as 9-styryluane 1-hracene compounds described in Japanese Patent Application Laid-open No. 94828 and Japanese Patent Application Laid-open No. 51-94829 have been proposed.

These low-molecular-weight organic photoconductors have been able to overcome the drawbacks of film-forming properties that have been a problem in the field of organic photoconductive polymers by appropriately selecting the interlayer used. It is not sufficient in terms of sensitivity.

For this reason, in recent years, a laminated structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer has been proposed. An electrophotographic photoreceptor using this laminated structure as a photosensitive layer can now be improved in terms of sensitivity to visible light, surface strength of '1 settling force, etc.

Such an Eko photographic photoreceptor is manufactured by, for example, the US 4.1
It is described in F Patent No. 3837851, Patent No. 3871882, Japanese Patent Publication No. 62-55655, etc.

However, conventional photoreceptors using low-molecular-weight organic photoconductors in the charge transport layer do not always have sufficient sensitivity characteristics, especially after repeated use. i? There is a large variation in bright area potential and dark area potential after exposure and exposure, and there are points that need to be improved.

[Problems to be Solved by the Invention] An eleventh object of the present invention is to provide an electrophotographic photoreceptor that eliminates the above-mentioned drawbacks or disadvantages.

Furthermore, another object of the present invention is to provide a novel charge 1 trapping material in a laminated photosensitive layer in which a charge generation layer and a charge transport layer are functionally separated.

[Solving the Problems] The present invention comprises an electrophotographic photoreceptor characterized by having a layer containing a dibenzodiazine compound represented by the following general formula (1).

Examples include groups.

Representative examples of the dibenzodiazine compounds represented by the general formula (1) are listed below.

Compound Example (1) In the formula, R1, R2, R3 and R4 represent a hydrogen atom, an alkyl group or an alkoxy group which may have an n substituent.

Specifically, the alkyl groups represented by R1, R2, R3 and R4 include groups such as methyl, ethyl and propyl;
Examples of alkoxy groups include methoxy, ethoxy, and propoxy, and examples of substituents in the above groups include fluorine, chlorine, and iodine.

Halogen atoms such as bromine, alkyl groups such as methyl, ethyl, propyl, alkoxy groups such as methoxy, ethoxy, propoxy, phenyloxy groups such as dimethylamino, diethylamino, diphenylamino, ditolylamino, dimethoxyphenylamino, piperidino, piperazino, etc. 'l P4. Amino Compound Example (2) Compound Example (3) Compound Example Compound Example (5) Compound Example (8) Compound Example Compound Example (9) Compound Example Compound Example (io) Dibenzodiazine compound represented by the above general formula (1) can be easily synthesized by subjecting phenazine and iodized benzene to the Ullmann reaction.

In a preferred embodiment of the present invention, a dibenzodiazine compound represented by the general formula (1) is used as a charge transporting material in an electrophotographic photoreceptor in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer.

The charge transport layer in the present invention is preferably formed by applying a solution of the dibenzodiazine compound represented by the general formula (1) and a binder dissolved in a suitable solvent and drying the solution.

Examples of the binder used here include polyarylate,
Polysulfone, polyamide, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, acetic acid vinyl resin, phenolic resin, epoxy resin, polyester, fluorocarbon resin, polycarbonate, polyurethane, or two or more repeating units of these resins! Examples of the copolymer 1 include styrene-butadiene copolymer, styrene-acrylonitrile copolymer, and styrene-maleic acid copolymer. Also,
In addition to such insulating polymers, organic photonic sA such as polyvinyl cartazoole, polyvinylanthracene, and polyvinylpyrene are also available. tt polymers can also be used.

The blending ratio of this binder and the specific dibenzodiazine compound is 100 Ir! It is preferable that the dibenzodiazine compound corresponding to lj is 10 to 500 parts by weight.

The charge transport layer is electrically connected to the charge generation layer below and has the function of receiving charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. ing. In this case, this charge transport layer may be laminated on or under the charge generation layer, but the charge transport layer may be laminated on F of the charge generation layer. is desirable.

Since this charge transport layer has a limit in which it can transport a load carrier, it cannot be made thicker than necessary, although it is 5 to 30 gm for boat fishing.

The preferred range is 8 to 20 μm.

The organic solvent used to form such a charge transport layer varies depending on the type of binder used, but it is preferable to select one that does not dissolve the charge generation layer or underlying subbing layer. Examples of organic solvents include alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, amides such as N,N-dimethylpol-11amide, N,N-dimethylacetamide, and dimethyl sulfoxide. Sulfoxides, ethers such as tetrahydrofuran, dioxane and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate,
Aliphatic halogenated hydrocarbons such as methylene chloride, dichloroethylene, carbon tetrachloride, trichloroethylene, or benzene, toluene, xylene, monochlorobenzene,
Aromatic compounds such as dichlorobenzene can be used.

Coating methods include dip coating, spray coating, spinner coating, bead coating,
This can be carried out 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 done by drying to the touch at room temperature and then heating. Drying by heating should be carried out at a temperature of 30 to 200°C for 5 minutes to 2 hours for boat fishing on a quiet 1F or under ventilation. is preferred.

The charge transport layer in the present invention may contain various additives. Such additives include diphenyl 31, diphenyl 31, 0-terphenyl, P-terphenyl, sibutyl phthalate, dimethyl glycol phthalate, dioctyl phthalate, triphenyl phosphoric acid, methylnaphthalene, benzophenone, chlorinated paraffin,
Examples include dilaurylthiopropionate, 3,5-dinitrosalicylic acid, and various fluorocarbons.

The charge generation layer in the present invention includes selenium, selenium-tellurium, biryllium-based dye 1, thiapyrylium-based dye 1. Azulenium dye 1. Phthalocyanine pigments, andanthrone pigments, dibenzpyrenequinone pigments 1. Pyranthrone pigment, trisazo pigment, disuane pigment 4, monoazo pigment 1, indigo pigment, quinacridone pigment, thiacyanin, asymmetric quinocyanine, quinocyanin or +
A separate adhesion layer or resin dispersion layer selected from charge generating materials such as amorphous silicon as described in Japanese Patent Publication No. 54-143645 may be used.

Specifically, for example, the following inorganic compounds or organic compounds are exemplified as representative examples of the electron 1XI generator used in the electron photoreceptor of the present invention.

ti: (=:j Examples of generated substances (1) Amorphous silicon (2) Selenium-tellurium (l 1) (l 7) (l 9) (l 3) (l 4) (2l) Methine squaric acid dye Indigo dye (C, 1, No, 78000) Thioindigo dye (C, 1, No, 78800) (31) β-type copper phthalocyanine (4B) 4- (4-dimethylaminophenyl) 2.6
- The charge-generating layer of cyphenylthiapyrylium perchlorate can be formed by dispersing the charge-generating substance described above in a suitable binder and coating it on a support, or by depositing it by vacuum deposition equipment. It can be formed by forming a film.

The binder can be selected from a wide range of insulating resins and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene.

Preferably polyvinyl butyral, polyarylate (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinylpyridine, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol,
Examples include polyvinylpyrrolidone.

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

Organic solvents used during coating include alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and amides such as N,N-dimethylformamide and N,N-dimethylacetamide. , sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, and aliphatics such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene. Halogenated hydrocarbons or aromatics such as benzene, toluene, xylene, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating can be carried out using the same coating method as in the formation of the "crL cargo transport layer."

The charge generation layer contains as much of the organic photoconductor as possible in order to obtain sufficient absorbance and a thin film layer, for example 5A, to reduce the range of the generated charge carriers.
It is desirable to form a thin film layer having a thickness of Lm or less, preferably 0.01 to Igm.

A photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer is provided on a support having a conductive layer. As the support having a conductive layer, the support itself is conductive, such as aluminum, aluminum alloy, copper,
Zinc, stainless steel, henadium, molybdenum, chromium,
Titanium, nickel, indium, gold, platinum, etc. can be used, and in addition, aluminum, aluminum alloy, indium oxide, tin oxide, indium oxide-tin oxide alloy, etc. can be used to form a film using the vacuum base layering method. Plastics (e.g. polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluoroethylene, etc.), conductive particles (e.g. aluminum powder, titanium oxide, tin oxide,
Zinc oxide.

A support in which carbon black, tR granules, etc.) is coated on a plastic or the above-mentioned support with a suitable binder, a support in which plastic or paper is impregnated with conductive particles, a plastic containing a conductive polymer, etc. can be used. can.

A subbing layer having a barrier function and an adhesive resin can also be provided between the conductive support and the photosensitive layer.

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

The thickness of the subbing layer is 0.1 to 5 gm, preferably 0.5 to 3 gm.
Le m is appropriate.

When using a photoreceptor having V1 layers in this order of a conductive support, a charge generation layer, and a charge transport layer, the dibenzodiazine compound in the present invention has hole transport properties, so the surface of the charge transport layer is negatively charged. When exposed to light after charging, the holes generated in the charge generation layer are injected into the charge transport layer in the exposed area, and then reach the surface and neutralize the negative charge, resulting in attenuation of the surface potential and the unexposed area. An electrostatic contrast occurs between and ′.

During development, it is necessary to use positively charged toner.

In another specific example of the present invention, the above-mentioned azo pigment or the biryllium dyes, thiapyrylium dyes, selenapyrylium dyes, and benzene dyes disclosed in U.S. Pat. Pyrylium dye, benzothiapyrylium dye,
Pigments and dyes having photoconductivity such as naphthopyrylium dye 4 and naphthothiapyrylium dye can also be used as sensitizers.

In another specific example, a eutectic complex of a biryllium dye and an electrically insulating polymer having an alkylidene diarylene moiety as disclosed in US Pat. No. 3,684,502 and the like can be used as a sensitizer. This eutectic complex is, for example, 4-[4-bis(2-chloroethyl)aminophenyl]
-2,6-Cyphenylthiavirylium perchlorate and poly(4,4°-isopropylidene diphenylene carbonate) are mixed in a halogenated hydrocarbon solvent such as dichloromethane, chloroform, carbon tetrachloride, 11-dichloroethane, 1. After dissolving in 2-dichloroethane, 1.1.2-1-lichloroethane, chlorobenzenebromobenzene, 1,2-dichlorobenzene, etc., a nonpolar solvent,
For example, it can be obtained as a particulate eutectic complex by adding hexane, octane, decane, 2,2,4-)limethylbenzene, ligroin, etc.

The electrophotographic photoreceptor in this specific example includes styrene-butadiene copolymer, silicone resin vinyl resin, vinylidene chloride-acrylonitrile copolymer, styrene-butadiene copolymer,
Acrylonitrile copolymer, vinyl acetate-IP
i-vinyl copolymer polyvinyl petyral, polymethyl methacrylate, poly-N-butyl methacrylate,
Polyesters, cellulose esters, etc. can be contained as a binder.

Furthermore, as another specific example of the present invention, the dibenzodiazine-based compound represented by the general formula (1) may be added to the same photosensitive layer together with a charge-generating substance, in addition to the functionally separated electrophotographic photoreceptor described above. Examples include electrophotographic photoreceptors containing the above.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines but also in a wide range of electrophotographic applications such as laser beam printers, CRT printers, and electrophotographic plate making systems.

The electrophotographic photoreceptor of the present invention has the advantage of high sensitivity and small fluctuations in bright area potential and dark area potential when repeatedly charged and exposed.

[Example] Example 1 β-type copper phthalocyanine (trade name L-io no I
Blue NCB Toner, bundle diameter ink manufacturing■
After sequentially refluxing the product) in water, ethanol and benzene,
7 g of filtered and purified pigment, polyester (trade name: Polyester Adhesive 49,000, solid content 20%, DuPont S8 14 g, toluene 35 g, dioxane 3
A coating liquid was prepared by mixing 5 g of ii! and dispersing it in a ball mill for 6 hours. Made by l. This coating solution was applied to an aluminum sheet using a Mayer bar so that the dry film thickness was 0.5 μm to form a charge generation layer.

Next, 7 g of Compound Example (1) as a charge transport substance and 7 g of polycarnate (trade name: Panlite -1300, manufactured by Teijin Kasei Ltd.) were stirred and dissolved in a mixed solvent of 35 g of tetrahydrofuran and 35 g of chlorobenzene. Apply the solution onto the charge generation layer using a Mayer bar until the dry film thickness is 16g.
An electrophotographic photoreceptor was prepared by coating to form a charge transport layer.

This electrophotographic photoreceptor was statically charged with a corona at 15 KV using a static copying paper tester Model EPA-8100 manufactured by Kawaguchi Electric Co., Ltd., held in a dark place for 1 second, and then exposed to light at an illuminance of 2.5 lux. The charging characteristics were investigated.

As for the charging characteristics, the surface potential (vO) and the exposure amount (El/'2) required to attenuate the potential (V) when dark decayed for 1 second to 1/2 were measured.

Furthermore, in order to measure the fluctuations in bright area potential and dark area potential during repeated use, we attached the above to the photosensitive drum cylinder of a Canon PPC copying machine NP-1502, and made so many copies using the same machine. conduct, initial and 50,0
Bright area potential (VL) and dark area potential (V
D) fluctuations were measured.

In addition, in place of Compound Example (1), using the compound of the structural formula as Comparative Compound 1 and the compound of the structural formula as Comparative Compound 2, the electrons of Comparative Sample 1 and Comparative Sample 2 were A photographic photoreceptor was prepared and measured in the same manner.

Show the results.

Example 1 Comparative sample 1 Comparative sample 2 Initial 1, 5 2, 9 2, 7 After 50,000 sheets durability Example 1 650 150 640 160 Comparative sample 1 640 230 580 350 Comparative sample 2 64
0 190 590 330 That is, it can be seen that the electrophotographic photoreceptor of the present invention has high sensitivity and excellent durability stability.

Examples 2 to 8 Compound example (2) was used instead of compound example (1) used in Example 1.
), (3), (4), (5), (6).

Electrophotography corresponding to Examples 2 to 8 using the compounds (8) and (10) as the charge transporting substance and using the pigment of charge generation substance example (21) as the charge generation substance, except that the other conditions were the same as in Example 1. A photoreceptor was created.

The electrophotographic properties of each photoreceptor were measured in the same manner as in Example 1. Show the results.

Initial 690 1.2 680 1.4 680 1.6 670 2.0 690 1.7 680 2.1 690 1.5 After 50,000 sheets of durability Example V 1) V L V p V L
(-V) (-V) (-v) (
-v) Example 9 Aluminum cylinder
Water 222m9. ) was applied using a dip coating method and dried to form a subbing layer with a coating weight of 1.0 g/m2.

Next, 1 part by weight of charge-generating substance example (43), 1 part by weight of butyral resin (trade name Kosuretsu BM-2, manufactured by Tsukiki Kagaku ■) and 30 parts by weight of inpropyl alcohol were dispersed in a ball mill for 4 hours.

This dispersion was applied to the previously formed subbing layer by dip coating and dried to form a charge generating layer. The film thickness was 0.3 μm.

Next, 1 part by weight of Compound Example (3), 1 part by weight of polysulfone (trade name P1700, manufactured by Union Carbide), and 6 parts by weight of chlorobenzene were mixed and dissolved by stirring with a stirrer. This liquid was applied onto the charge generation layer by dip coating and dried to form a charge transport layer. This film thickness is 20μ
It was m.

-5KV was applied to the electrophotographic photoreceptor thus created.
A corona discharge was performed.

The surface potential at this time was measured (initial potential Vo).

Furthermore, the surface potential of this photoreceptor was measured after it was left in a dark place for 5 seconds (decay).The sensitivity was determined by the potential V after dark decay.
Evaluation was made by measuring the exposure amount (El/2 microjoules/cm2) required to attenuate K by half. At this time, the light source was a gallium/aluminum/propylene ternary semiconductor laser (output: 5 mW, oscillation wavelength: 780 nm).
m) was used. These results were as follows.

Vo knee 700V Potential holding rate (VK /VOX 100): 95%E
l/2: 1.2 microjoules/cm2 Next, the photoreceptor was transferred to a laser beam printer (LBP-CX manufactured by Canon), which is a reversal development type electrophotographic printer equipped with the same semiconductor laser. An actual image forming test was conducted by setting it in place of the photoreceptor.

The conditions are as follows.

Surface potential knee after primary charging 700V, surface potential knee after image exposure 180V (exposure amount 2, 5 μJ/cm2), transfer potential: +700V, developer polarity: negative polarity, process speed: 50mm/sec, development conditions ( Development bias) knee 450V, image exposure scanning method: image scan, - exposure before next charging: 301 ux, red full exposure at seC, image formation was performed by line scanning a laser beam according to the character signal and image signal, but one character, Good prints were obtained for both images.

Example 10 3 g of 4-(4-dimethylaminophenyl)-2,6-siphenylthiavirillium perchlorate and compound example (6
) of polyester (Polyester Adhesive 4
9000 (manufactured by DuPont) in 100 mJl of toluene (50)-dioxane (5o) solution and dispersed in a ball mill for 6 hours. The film thickness after drying this dispersion is 15 μm.
It was applied onto an aluminum sheet using a Mayer bar so that

The electrophotographic properties of the electrophotographic photoreceptor thus prepared were measured in the same manner as in Example 1.

Show the results.

Vo Knee 710V Vl Knee 680V El/2: 1.71ux, sec ['' VD Knee 640V VL Knee 190V ΣGoyurukyou Kyou Vo Knee 620V VL Knee 180V Example 11 Zein 11.2g, 28% ammonia water 1g, water 222
M) was coated with a Meyer bar and dried to form an adhesive layer with a thickness of 1 μm.

Next, 5 g of the azo pigment of the charge generating substance example (9) and 2 g of butyral resin (degree of butyralization 63 mol%) were mixed with 9 mol of ethanol.
After dispersing it together with a solution dissolved in 5 mJL, it was coated on the adhesive layer to form a charge generation layer having a film thickness of 0°4#Lm after drying.

Next, a solution prepared by dissolving 5 g of compound example (10) and 5 g of poly-4,4-dioxydiphenyl-2,2-propane carbonate (viscosity average molecular weight 30,000) in 150 mL of dichloromethane was applied onto the charge generation layer and dried. Then, an electrophotographic photoreceptor was prepared by forming a charge transport layer having a film thickness of 201 Lm.

The electrophotographic properties of the electrophotographic photoreceptor were measured in the same manner as in Example 1. Show the results.

VQ Knee 710V Vl Knee 690V El/2: 2.0 Sentence ux, sec Ammonia aqueous solution of casein on an aluminum plate Example 12 Surface-cleaned O!2mm thick molybdenum plate (
(substrate) was fixed in place within the glow discharge deposited layer.

Next, the inside of the layer was evacuated to a vacuum level of about 5XIO-6 torr. Thereafter, the input voltage of the heater was increased to stabilize the molybdenum substrate temperature at 150°C. After that, hydrogen gas and silane gas (15% by volume relative to hydrogen gas) were introduced into the layer, and the gas flow rate and vapor deposition layer main valve were adjusted to 0.5%.
5 MHz to zero-order induction coil stabilized at torr
A high frequency power of 30 W was applied to generate a glow discharge inside the coil in the layer, resulting in an input power of 30 W. J: An amorphous silicone film was grown on a substrate under the conditions described above, and the same conditions were maintained until the film thickness reached 2 pm, after which glow discharge was discontinued. After that, the heating heater and high frequency power supply are turned off, and after waiting for the substrate temperature to reach 100℃, the hydrogen gas and silane gas outflow valves are closed, and after the inside of the layer is lowered to 1O-5 torr or less, it is returned to atmospheric pressure. , took out the board.

Next, a charge transport layer was formed on this amorphous silicon layer in exactly the same manner as in Example 1 except that Compound Example (8) was used as the charge transport material.

The created electrophotographic photoreceptor was installed in a charging exposure experiment equipment,
It was corona charged at -6 KV and immediately irradiated with a light image. The light image was illuminated through a transmission type test chart using a tungsten lamp light source.

Immediately thereafter, a positively charged developer (containing toner and carrier) was cascaded onto the photoreceptor surface to obtain a good toner image on the photoreceptor surface.

[Effects of the Invention] By using a specific dibenzodiazine compound as a charge transport material, the electrophotographic photoreceptor of the present invention has high sensitivity and high durability (significantly less potential fluctuation due to repeated use), and is suitable for electrophotography. It has the remarkable effect of being applicable to a wide range of fields of use.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor comprising a layer containing a dibenzodiazine compound represented by the following general formula (1). General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) In the formula, R_1, R_2, R_3 and R_4 represent a hydrogen atom, an alkyl group or an alkoxy group which may have a substituent.