JP3255525B2 - Pyrazine compound and electrophotographic photoreceptor containing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel pyrazine compound useful for an electrophotographic photosensitive member and an electrophotographic photosensitive member containing the pyrazine compound.

[0002]

2. Description of the Related Art Conventionally, as a photosensitive layer of an electrophotographic photosensitive member,
Inorganic photoconductive materials such as selenium, selenium-tellurium alloy, and zinc oxide have been widely used.In recent years, research on electrophotographic photoreceptors using organic photoconductive materials has progressed, and some of them have been put into practical use. ing. Here, most of the photoconductors that have come into practical use are laminated electrophotographic photoconductors each having a photosensitive layer in which functions are separated into a charge generation layer and a charge transport layer. Actively designed electrophotographic photoreceptors that take advantage of organic photoconductive materials such as safety and versatility at low cost, improved in sensitivity and photoreceptor life, which were inferior to the body. It became so.

[0003] This type of laminated electrophotographic photoreceptor generally comprises a charge generation layer composed of a charge generation substance such as a pigment or a dye, and a charge transport layer composed of a charge transport substance such as hydrazone or pyrazoline on a conductive support. Are formed in order, and due to the nature of the electron-donating charge transporting substance, it becomes a hole-transfer type and has sensitivity when the surface of the photoreceptor is negatively charged. However, in the negative charging, the corona discharge used at the time of charging is unstable compared to the positive charging, and ozone,
It generates nitrogen oxides and the like, and is liable to cause physical and chemical deterioration such as adsorption on the photoreceptor surface.In addition, there is a problem that the environment is deteriorated. However, it is difficult to manufacture the positive polarity toner from the viewpoint of the triboelectric series with respect to the ferromagnetic carrier particles. In the two-component high-resistance magnetic brush developing system, the negatively charged toner / developing toner is used. The agent is more stable and has a greater degree of freedom in selection and use conditions. In this respect, the application range of the positively chargeable photoreceptor is wider and more advantageous.

Therefore, it has been proposed to use a photoreceptor using an organic photoconductive substance by positive charging. For example, when forming a photoreceptor by laminating a charge transport layer on the charge generation layer, the charge transport layer has a large electron transport ability, for example, 2,
Although 4,7-trinitro-9-fluorenone and the like are used, there is a problem that the substance is carcinogenic and is extremely unsuitable for occupational health. As the electron transporting compound, a fluorenidenemethane compound is used in JP-A-60-69657, and an anthraquinodimethane and an anlone derivative are used in JP-A-61-233750. Both have problems with the repetition characteristics, and also have problems to be improved, such as poor compatibility with the binder resin. Further, as a positively charged photoreceptor, US Pat.
No. 5,414 discloses thiapyrylium salts (charge generating substances)
Is contained so as to form a eutectic complex with polycarbonate (binder resin). However, this known photoreceptor has the disadvantage that the memory phenomenon is large and ghosts are likely to occur.

Therefore, the charge generating layer containing a charge generating substance which generates holes and electrons upon light irradiation is defined as an upper layer (surface layer), and the charge transporting layer including a charge transporting substance having a hole transporting property is defined as a lower layer. It is conceivable to use a photoreceptor having a laminated photosensitive layer for positive charging. However, since the layer containing the charge generating substance is formed as a surface layer on the positively charged photoreceptor, it is hardly exposed to external effects such as short-wavelength light irradiation such as ultraviolet rays, corona discharge, humidity, and mechanical friction during light irradiation. The fragile charge generating material is present in the vicinity of the surface layer, so that the electrophotographic performance is degraded during storage of the photoreceptor and during the image forming process, and the image quality is degraded. In a conventional negatively charged photoreceptor having a charge transport layer as a surface layer, the influence of the various external effects is extremely small, and the charge transport layer has a function of protecting a lower charge generation layer.

Therefore, it is conceivable to provide a thin protective layer made of, for example, an insulating and transparent resin to protect the layer containing the charge generating substance from external action. The light irradiation effect is lost due to blocking, and when the thickness of the protective layer serving as the surface layer is large, the sensitivity is reduced. As described above, various attempts have been made to obtain a positively charged photoreceptor, but all of them have many problems to be improved in light sensitivity, memory phenomenon, occupational health and the like.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a pyrazine compound used for an electrophotographic photoreceptor, and an electrophotographic photoreceptor comprising a conductive support provided with a photosensitive layer containing a charge generating substance and a charge transporting substance. It is another object of the present invention to provide a highly sensitive and durable electrophotographic photoreceptor characterized in that the pyrazine compound is used as a high-performance charge transporting substance having good compatibility with a binder resin.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted various studies to solve the above problems, and as a result, have found a specific group of compounds, thereby completing the present invention. That is, according to the present invention, a pyrazine compound represented by the following general formula (I) is provided.

Embedded image Ｘwhere X is = C (Y) (Z) or = N (C
N), Y and Z represent H, cyano group, COOR, substituted or unsubstituted phenyl group, substituted or unsubstituted naphthyl group, or substituted or unsubstituted pyridyl group (here, R
Represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted phenyl group. ) And W represent an alkyl group, a halogen atom, an alkoxycarbonyl group, a phenyl group, a cyano group, or a nitro group, respectively. n
Represents an integer of 0 to 4. ｝ Further, according to the present invention, in an electrophotographic photoreceptor having a conductive support and a photosensitive layer provided thereon as an essential component,
An electrophotographic photoreceptor characterized in that the photosensitive layer contains the pyrazine compound represented by the general formula (I), wherein the photosensitive layer comprises a charge generation layer and a charge transport layer, At least the above-mentioned general formula (I) in the charge transport layer
An electrophotographic photoreceptor characterized by containing a pyrazine compound represented by is further provided, wherein the photosensitive layer comprises at least a charge generation material, a single layer having a charge transport material as an essential component, An electrophotographic photoreceptor comprising the pyrazine compound represented by the general formula (I) as the charge transporting material is provided.

Hereinafter, the present invention will be described in more detail. In the general formula (I), the substituent of the phenyl or naphthyl group of Y, Z, or R is an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a t-butyl group, or a methoxy group. Or an alkoxy group such as an ethoxy group, a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom, a halogenated alkyl group such as a trifluoromethyl group, an alkoxycarbonyl group such as a methoxycarbonyl group, a substituted or unsubstituted phenoxy Examples include a carbonyl group, a substituted or unsubstituted naphthoxycarbonyl group, an acyl group, a cyano group, and a nitro group.
Examples of the substituent of the alkyl group for R include an alkoxy group such as a methoxy group and an ethoxy group, and a halogen atom such as a fluorine atom and a chlorine atom.

Specific examples of the pyrazine compound represented by the general formula (I) are shown in Tables 1 and 2 below, but are not limited thereto.

[0011]

[Table 1- (1)]

[0012]

[Table 1- (2)]

[0013]

[Table 1- (3)]

[0014]

[Table 1- (4)]

[0015]

[Table 1- (5)]

[0016]

[Table 1- (6)]

[0017]

[Table 1- (7)]

[0018]

[Table 1- (8)]

[0019]

[Table 1- (9)]

[0020]

[Table 1- (10)]

[0021]

[Table 1- (11)]

[0022]

[Table 1- (12)]

[0023]

[Table 1- (13)]

[0024]

[Table 1- (14)]

[0025]

[Table 1- (15)]

[0026]

[Table 1- (16)]

[0027]

[Table 1- (17)]

[0028]

[Table 2]

Next, a method for producing the pyrazine compound represented by the general formula (I) of the present invention will be described. The reaction formula for producing the pyrazine compound represented by the general formula (I) is shown in Table 3 below. First, a ninhydrin compound (I
The pyrazine compound (VI) can be obtained by heat-reacting V) with diaminomaleonitrile (V). The reaction is usually carried out without solvent, a polar solvent such as methanol, ethanol, isopropanol, 1-butanol, acetic acid, tetrahydrofuran, 1,4-dioxane or N, N-dimethylformamide, or benzene, toluene, monochlorobenzene or xylene. It can be performed in an aromatic solvent. The reaction temperature is from room temperature to 150 ° C, preferably from room temperature to 100 ° C.

Next, a pyrazine compound represented by the general formula (VI) and a methylene compound represented by the general formula (VII) shown in Table 3 below are reacted under both acidic and basic catalysts to give a general compound. A pyrazine compound represented by the formula (II) can be obtained. Examples of the acidic catalyst used include organic acids such as acetic acid and p-toluenesulfonic acid, inorganic acids such as sulfuric acid, and Lewis acids such as zinc chloride and titanium tetrachloride. Examples of the basic catalyst include organic bases such as pyridine, piperidine, N-methylpiperidine, morpholine, N-methylmorpholine, and triethylamine; acetates such as sodium acetate, potassium acetate, and ammonium acetate; caustic soda, caustic potassium, and carbonate. Examples include inorganic bases such as potassium, metal alkoxides such as sodium methylate, sodium ethylate, and potassium t-butoxide. The reaction is usually solventless or
The reaction can be performed with a halogen-based solvent such as dichloromethane and 2-dichloroethane, and a polar solvent such as methanol, ethanol, butanol, tetrahydrofuran, 1,4-dioxane, and NN-dimethylformamide.

The pyrazine compound (III) can be obtained by condensing the pyrazine compound (VI) with bis (trimethylsilyl) carbodiimide (VIII) in the same solvent as described above using the acid as a catalyst. Compounds (II) and (III) are included in the pyrazine compound represented by the general formula (I).

[0032]

[Table 3]

The pyrazine compound of the present invention can be used not only as a charge transporting substance for an electrophotographic photoreceptor, but also suitably as an electronic device such as a solar cell or an organic EL device in the field of electronics.

Next, the structure of the photoreceptor of the present invention will be described with reference to the drawings. As the photoreceptor, for example, as shown in FIG. 1, a layer (charge generation layer) containing a charge generation substance and, if necessary, a binder resin on a support 1 (a conductive support or a sheet provided with a conductive layer). 2) A layer containing 2 as a lower layer and containing a charge transport material and, if necessary, a binder resin (charge transport layer)
3, a protective layer 5 provided on the photosensitive layer 4 of FIG. 1 as shown in FIG. 2, and a support as shown in FIG. A single-layered photoconductor layer 6 containing a charge generating substance, a charge transporting substance, and, if necessary, a binder resin is provided thereon. A protective layer may be provided on the upper layer, and an intermediate layer may be provided between the support and the photoreceptor layer.

As the charge generating substance used in the present invention, any of inorganic substances and organic substances can be used as long as they absorb visible light and generate free charges. For example, amorphous selenium, trigonal selenium, selenium-arsenic alloy, selenium-tellurium alloy, cadmium sulfide,
Inorganic substances such as cadmium selenide, cadmium sulfate selenide, mercury sulfide, lead oxide, lead sulfide, amorphous silicon, or bisazo dyes, polyazo dyes, triarylmethane dyes, thiazine dyes, oxazine dyes, xanthene dyes Dye, cyanine dye, styryl dye, pyrylium dye, quinacridone dye, indigo dye, perylene dye, polycyclic quinone dye, bisbenzimidazole dye, indanthrone dye, squarylium dye, anthraquinone dye Dyes and organic substances such as phthalocyanine dyes are exemplified.

In the present invention, examples of the binder resin usable for the photoreceptor layer include polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin,
Addition polymerization type resin such as vinyl acetate resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, polyaddition type resin, polycondensation type resin, and repetition of these resins Insulating resins such as vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin containing two or more units, and poly-N-vinyl carbazole And the like.

As the conductive support for supporting the photoreceptor layer, a metal plate such as aluminum or nickel, a metal drum or metal foil, a plastic film on which aluminum, tin oxide, indium oxide or the like is deposited, or a conductive material is applied. Films or drums of dipped paper, plastic, etc. can be used.

In the case where the photoreceptor according to the present invention is formed in a laminated structure of a charge generation layer and a charge transport layer, that is, in the case of FIGS. It can be formed by vapor deposition, or by dissolving or dispersing in a suitable solvent alone or together with a suitable binder resin, followed by coating and drying. When the charge generation material is dispersed to form a charge generation layer, the charge generation material is preferably a powder having an average particle size of 2 μm or less, preferably 1 μm or less. That is, if the particle size is too large, the dispersion in the layer will be poor, and the particles will partially protrude to the surface, resulting in poor surface smoothness. In some cases, discharge will occur at the protruding portions of the particles or toner The toner filming phenomenon easily occurs due to the adhesion of the particles. However, if the above-mentioned particle size is too small, on the contrary, it tends to agglomerate, increasing the resistance of the layer, decreasing the sensitivity and repetition characteristics due to the increase in crystal defects, or limiting the fineness of the layer. The lower limit of the diameter is preferably set to 0.01 μm.

The charge generation layer can be provided by the following method. That is, the charge generating material is made into fine particles in a dispersion medium by a ball mill, a homomixer, or the like,
This is a method of applying a dispersion obtained by adding and mixing and dispersing a binder resin. In this method, when the particles are dispersed under the action of ultrasonic waves, uniform dispersion is possible. In the charge generation layer, the ratio of the charge generation material contained in the binder resin is set to 20 to 200 parts by weight based on 100 parts by weight of the binder resin. The thickness of the charge generation layer formed as described above is preferably 0.1 to 10 μm, and particularly preferably 0.5 to 5 μm.

Next, the charge transport layer of the present invention can be formed by applying the pyrazine compound as a charge transport substance dissolved or dispersed in a suitable solvent alone or with a suitable binder resin, followed by drying and then drying. Provided in the same way as Examples of the solvent used for the charge transport layer include N, N-dimethylformamide, toluene, xylene, monochlorobenzene, 1,2-dichloroethane, dichloromethane, 1,1,1-trichloroethane,
Examples thereof include 1,2-trichloroethylene, tetrahydrofuran, methyl ethyl ketone, cyclohexanone, ethyl acetate, and butyl acetate. In this charge transport layer,
The ratio of the charge transport material contained in the binder resin is such that the charge transport material is 20 to 2 parts by weight based on 100 parts by weight of the binder resin.
Used at a rate of 00 parts by weight. At this time, the thickness of the charge transport layer is preferably 5 to 50 μm, particularly preferably 5 to 50 μm.
30 μm.

Next, when the photoreceptor of the present invention is formed in a single layer structure, that is, in the case of FIG. 3, the ratio of the charge generating substance and the charge transporting substance contained in the binder resin is 100 parts by weight of the binder resin. The charge generating material is used in an amount of 20 to 200 parts by weight, and the charge transporting material is used in an amount of 20 to 200 parts by weight. The thickness of the photoreceptor having a single-layer structure is 7 to 50 μm, and more preferably 10 to 30 μm.

The intermediate layer functions as an adhesive layer or a barrier layer. In addition to the above-mentioned binder resin, for example, polyvinyl alcohol, ethyl cellulose,
Carboxymethylcellulose, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, casein, resins such as N-alkoxymethyl nylon, or those in which tin oxide or indium is dispersed, Aluminum oxide, zinc oxide,
Alternatively, a deposited film of silicon oxide or the like is used. The thickness of the intermediate layer is desirably 1 μm or less. As the material used for the protective layer, it is appropriate to use the above-mentioned resin as it is or to disperse a low-resistance substance such as tin oxide or indium oxide. Further, an organic plasma polymerized film can also be used, and the organic plasma polymerized film may be appropriately formed of oxygen, nitrogen, halogen, and
It may contain Group V and Group V atoms.

[0043]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In the examples, "parts" are "parts by weight" unless otherwise specified.

Synthesis Example 1 [Synthesis of compound of general formula (VI), n = 0] 8.91 g of commercially available ninhydrin and 5.41 g of commercially available diaminomaleonitrile were added to 200 m of isopropyl alcohol.
The mixture was stirred for 2 hours under reflux in the flask. After the reaction, the reaction mixture was allowed to cool to room temperature, and the precipitated crystals were separated by filtration. The obtained crude product was recrystallized from toluene to give pure product 7.16.
g was obtained. Decomposition point: 266.5 ° C. The infrared absorption spectrum of this product is shown in FIG.

Synthesis Example 2 [Synthesis of compound of general formula (II), Compound No. I-110] 2.32 g of the compound obtained in Synthesis Example 1 and 4.33 g of commercially available n-dibutyl malonate were added to 80 m of dichloromethane.
and 3.79 g of titanium tetrachloride in 1 under ice-cooling and stirring.
It was added dropwise over 0 minutes, and N-methylmorpholine 2.0 was added.
2 g was added dropwise over 10 minutes. After further stirring at room temperature for 4 hours, the mixture was poured into ice water, extracted with chloroform, and the chloroform layer was washed with water until neutral. After the chloroform layer was dried over magnesium sulfate, the solvent was distilled off. Then, the residue was subjected to column chromatography using chloroform as a developing solvent, and the obtained crude target product was recrystallized from ethanol to obtain a pure target product. 1.48 g of the product were obtained. Melting point: 147.9 to 149.0 ° C. The infrared absorption spectrum of this product is shown in FIG.

Synthesis Example 3 [Synthesis of Compound of General Formula (II)] In the same manner as in Synthesis Example 2, various compounds of general formula (II) were obtained. Table 4 shows the melting points and the results of elemental analysis of the compounds obtained as described above.

[0047]

[Table 4]

Example 1 5 parts of a bisazo dye represented by the following chemical formula (P-1) and a butyral resin (denkabutyral resin # 3000-2:
2.5 parts, manufactured by Denki Kagaku Kogyo) and tetrahydrofuran 9
2.5 parts were dispersed in a ball mill for 12 hours, and then tetrahydrofuran was added to a concentration of 2% by weight of the dispersion and redispersed to prepare a coating solution. The prepared dispersion was applied by casting with a doctor blade onto a 100 μm-thick polyester film on which aluminum was deposited, to form a charge generation layer having a dried thickness of 1.0 μm.

Embedded image On the charge generation layer thus obtained, 6 parts of an exemplary compound (Compound No. I-110), 10 parts of a polycarbonate resin (K-1300: manufactured by Teijin Chemicals), and methylphenyl silicon (KF50-100 cps: Shin-Etsu Chemical) Made)
A coating solution of a prescription consisting of 0.002 parts and 94 parts of tetrahydrofuran was prepared and cast and coated with a doctor blade to form a charge transport layer having a thickness of 20.0 μm after drying. A laminated electrophotographic photoreceptor (photoreceptor No. 1) composed of a layer and a charge transport layer was prepared.

Examples 2 to 4 In place of the exemplified compound (Compound No. I-110) of Example 1, Compound No. I-14, Compound No. I-21, Compound No. Photoconductor No. 1 was manufactured in the same manner as in Example 1 except that I-33 was used. 2. Photoconductor N
o. 3, photoconductor No. 4 was created.

Example 5 The same procedure as in Example 1 was carried out except that 6 parts of a trisazo dye represented by the following chemical formula (P-2) was used instead of 5 parts of a bisazo dye represented by the following chemical formula (P-1). A charge generating layer was formed by the method.

Embedded image On the charge generation layer thus obtained, 6 parts of an exemplary compound (Compound No. I-110), 10 parts of a polycarbonate resin (K-1300: manufactured by Teijin Chemicals), and methylphenyl silicon (KF50-100 cps: Shin-Etsu Chemical) Made)
A coating solution composed of 0.002 parts and 94 parts of tetrahydrofuran was prepared, and a charge transport layer having a thickness of 20.0 μm after drying was formed in the same manner as in Example 1. The aluminum electrode / charge generation layer / charge A laminated electrophotographic photoreceptor (photoreceptor No. 5) composed of a transport layer was prepared.

Examples 6 to 8 In place of the exemplified compound (Compound No. I-110) of Example 5, Compound No. I-14, Compound No. I-21, Compound No. Photoconductor No. 1 was manufactured in the same manner as in Example 5 except that I-33 was used. 6. Photoconductor N
o. 7, photoconductor No. 8 was created.

[0052] Example 9 x type metal-free phthalocyanine (P-3) 5 parts, polyvinyl butyral resin (LEC BLS: manufactured by Sekisui Chemical)
5 parts and 90 parts of tetrahydrofuran are dispersed in a ball mill for 12 hours, and then 2% by weight of tetrahydrofuran is dispersed.
And the resulting mixture was redispersed to prepare a coating solution. The prepared dispersion was deposited with aluminum 1
The solution was cast-coated on a polyester film having a thickness of 00 μm with a doctor blade to form a charge generation layer having a thickness of 0.5 μm after drying. On the charge generation layer thus obtained, 6 parts of the exemplified compound (Compound No. I-110) and 10 parts of a polycarbonate resin (K-1300: manufactured by Teijin Chemicals Ltd.)
And a coating solution of a formulation consisting of 94 parts of tetrahydrofuran, prepared by casting with a doctor blade, forming a charge transport layer having a thickness of 20.0 μm after drying, and forming an aluminum electrode / charge generation layer / A laminated electrophotographic photosensitive member (photosensitive member No. 9) composed of a charge transport layer was formed.

Examples 10 to 12 In place of the exemplified compound (Compound No. I-110) of Example 5, Compound No. I-14, Compound No. I-21, Compound No. Photoconductor No. 1 was manufactured in the same manner as in Example 9 except that I-33 was used. 10, photoconductor no. 11, photoconductor No. 12 was created.

The electrophotographic photosensitive member obtained as described above was subjected to a corona charging of +6 KV using an electrostatic copying paper tester (SP-42: Kawaguchi Electric Works), and was positively charged, and then 20 seconds. Left in a dark place, and the surface potential V
Then, light was irradiated using a tungsten lamp so that the illuminance on the surface became 40 lux, and the half-life exposure amount E1 / 2 (lux · sec) was measured. Table 5 shows the results.

[0055]

[Table 5]

Example 13 0.09 g of the compound (P-1), 15 g of a 10 wt% tetrahydrofuran solution of a polycarbonate resin (PC-Z, manufactured by Teijin Chemicals), and 0.9 of the donor compound (D-1)
g, 0.6 g of an exemplary compound (Compound No. 110 ) and 0.3 g of a 1 wt% solution of silicon oil (KF50: manufactured by Shin-Etsu Chemical) in tetrahydrofuran were weighed into a ball mill pot, and ball-milled for 24 hours to prepare a coating solution. The prepared coating solution was cast and applied on a 100 μm-thick polyester film on which aluminum was vapor-deposited with a doctor blade to prepare a single-layer electrophotographic photoreceptor having a thickness of about 20 μm after drying.

Embedded image

Comparative Example 1 A single-layer type electrophotographic photosensitive member was prepared in the same manner as in Example 13 except that the acceptor compound of the present invention was not added (photosensitive member No. 14).

The electrophotographic photosensitive member obtained as described above is subjected to a corona charging of +6 KV using an electrostatic copying paper tester (SP-428: Kawaguchi Electric Works), positively charged, and then for 20 seconds. It was left in a dark place, and the surface potential Vo at that time was measured. Then, light irradiation was performed using a tungsten lamp so that the illuminance on the surface became 40 lux, the half-life exposure amount E1 / 2 (lux · sec), and light irradiation 30 The surface potential Vr after 2 seconds was measured. Next, VO, E1 / 2, and Vr after the above operation were repeated 5000 times were measured, and the results are shown in Table 6.

[Table 4]

[0059]

The pyrazine compound according to the present invention can be produced by a relatively simple and efficient method and has excellent solubility or dispersibility in a binder resin. Further, the pyrazine compound functions as a charge transporting substance having an excellent ability to accept and transport charges generated from the charge generating substance, and an electrophotographic photoreceptor containing this pyrazine compound as a charge transporting substance was prepared. In this case, it has high sensitivity and high durability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a laminated electrophotographic photoreceptor of the present invention in which a charge generation layer and a charge transport layer are sequentially provided on a support.

FIG. 2 is a cross-sectional view of the electrophotographic photoreceptor of the present invention in which a protective layer is further provided on the electrophotographic photoreceptor having the cross section shown in FIG.

FIG. 3 is a cross-sectional view of a single-layer type electrophotographic photoreceptor of the present invention in which a photoreceptor layer is provided on a support.

FIG. 4 is an infrared absorption spectrum of the compound of Formula (VI) (n = 0) obtained in Synthesis Example 1.

FIG. 5: Compound No. obtained in Synthesis Example 2 FIG. 3 is an infrared absorption spectrum of I-110.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support 2 Charge generation layer 3 Charge transport layer 4 Photoconductor layer (laminated structure) 5 Protective layer 6 Photoconductor layer (single layer structure)

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Akio Kojima 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company, Ltd.

Claims (4)

(57) [Claims] 1. A pyrazine compound represented by the following general formula (I). Embedded image Ｘwhere X is = C (Y) (Z) or = N (C
N), Y and Z represent H, cyano group, COOR, substituted or unsubstituted phenyl group, substituted or unsubstituted naphthyl group, or substituted or unsubstituted pyridyl group (here, R
Represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted phenyl group. ) And W represent an alkyl group, a halogen atom, an alkoxycarbonyl group, a phenyl group, a cyano group, or a nitro group, respectively. n
Represents an integer of 0 to 4. ｝ 2. An electrophotographic photosensitive member comprising a conductive support and a photosensitive layer provided thereon as an essential component, wherein the pyrazine compound represented by the general formula (I) according to claim 1 is contained in the photosensitive layer. An electrophotographic photosensitive member characterized by containing: 3. The photosensitive layer comprises a charge generation layer and a charge transport layer, wherein at least the charge transport layer contains the pyrazine compound represented by the general formula (I) according to claim 1. The electrophotographic photosensitive member according to claim 2. 4. The method according to claim 1, wherein the photosensitive layer comprises at least a charge generating substance,
3. The charge transport material according to claim 2, wherein the charge transport material comprises a single layer, and the charge transport material contains a pyrazine compound represented by the general formula (I). Electrophotographic photoreceptor.