JPH07179440A - Pyrazine compound and electrophotographic photoreceptor containing the same - Google Patents

Abstract

PURPOSE:To obtain a new pyrazine compound, useful as a charge transport substance, etc., used in an electrophotographic photoreceptor and capable of providing the electrophotographic photoreceptor, having a high sensitivity and good in durability. CONSTITUTION:This pyrazine compound is expressed by formula I [X is C(Y)(Z) or N(CN); Y and Z each is H, CN or COOR (R is a substitutive alkyl or a substitutive phenyl), a substitutive phenyl, a substitutive naphthyl or a substitutive pyridyl; W is an alkyl, a halogen, an alkoxycarbonyl, phenyl, CN or NO2; n is 0-4]. The compound is obtained by thermally reacting a ninhydrin compound expressed by formula IV with a diaminomaleonitrile expressed by formula V, providing a pyrazine compound expressed by formula VI and then reacting the resultant compound with a methylene compound expressed by formula VII or bis(trimethylsilyl)carbodiimide expressed by formula VIII. Furthermore, this electrophotographic photoreceptor, having a high sensitivity and good in durability electrically conductive support of a charge generation layer and a charge transport layer and comprising the compound expressed by formula I in at least the charge transport layer.

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 photoreceptor and an electrophotographic photoreceptor containing the pyrazine compound as a charge transport material.

[0002]

2. Description of the Related Art Conventionally, as a photosensitive layer of an electrophotographic photoreceptor,
Inorganic photoconductive substances such as selenium, selenium-tellurium alloy, and zinc oxide have been widely used, but in recent years, research on electrophotographic photoreceptors using organic photoconductive substances has progressed, and some of them have been put to practical use. ing. Here, most of the photoconductors that have been put into practical use are laminated electrophotographic photoconductors that are composed of a photoconductive layer having a charge-generating layer and a charge-transporting layer, and a photoconductive layer made of an inorganic photoconductive material. The electrophotographic photoconductor is actively designed, which is improved in terms of sensitivity and photoconductor life, which are inferior to those of the human body, and is low in cost, and takes advantage of organic photoconductive substances such as safety and versatility. It became so.

This type of laminated electrophotographic photosensitive member is generally a charge generating layer made of a charge generating substance such as a pigment and a dye, and a charge transporting layer made of a charge transporting substance such as hydrazone and pyrazoline on a conductive support. Are sequentially formed. Due to the property of the electron transporting charge transport material, they are of the hole transfer type and have sensitivity when negatively charged on the surface of the photoreceptor. However, with negative charging, the corona discharge used during charging is more unstable than with positive charging, and ozone is about 10 times as much as during positive charging.
Nitrogen oxides are generated, which easily causes physical deterioration such as adsorption on the surface of the photoconductor and chemical deterioration, and further worsens the environment.There is also a problem that the negative polarity is used for developing the negative charging photoconductor. The toner of positive polarity has a problem that it is difficult to manufacture in view of the triboelectrification series with respect to the ferromagnetic carrier particles. In the two-component high resistance magnetic brush developing method, negatively charged toner / developing toner is used. The agent is more stable and has more flexibility in selection and use conditions, and in this respect as well, the range of application to the positive charging type photoreceptor is wide and advantageous.

Therefore, it has been proposed to use a photoconductor using an organic photoconductive material with a positive charge. For example, when a charge transport layer is laminated on the charge generation layer to form a photoreceptor, 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 has carcinogenicity and is extremely unsuitable for occupational health. Further, as the electron transport compound, a fluorenidene methane compound is used in JP-A-60-69657 and an anthraquinodimethane and an anron derivative are used in JP-A-61-233750. Both have problems in repeatability and have problems to be improved such as poor compatibility with binder resin. Further, as a positively charged photoreceptor, US Pat.
5,414, thiapyrylium salt (charge generating substance)
Is included so as to form a eutectic complex with polycarbonate (binder resin). However, this known photoconductor has a drawback that a memory phenomenon is large and a ghost is likely to occur.

Therefore, the charge generation layer containing a charge generation substance that generates holes and electrons at the time of light irradiation is used as an upper layer (surface layer), and the charge transport layer containing a charge transport substance having a hole transport ability is used as a lower layer. It is conceivable to use a photoreceptor having a laminated photosensitive layer for positive charging. However, since the positive charging photoreceptor is formed with a layer containing a charge generating substance as a surface layer, it is exposed to external effects such as irradiation of short wavelength light such as ultraviolet rays, corona discharge, humidity, mechanical friction, etc. Since the fragile charge generating substance is present in the vicinity of the surface layer, the electrophotographic performance is deteriorated during storage of the photoconductor and during the image formation process, and the image quality is deteriorated. In the conventional negative charging photoreceptor having the charge transport layer as the surface layer, the influence of the various external effects is extremely small, and rather the charge transport layer has a function of protecting the lower charge generating layer.

Therefore, for example, a thin protective layer made of an insulating and transparent resin may be provided to protect the layer containing the charge generating substance from an external action. However, the charge generated during light irradiation is the protective layer. The light irradiation effect is lost due to blocking, and the sensitivity is lowered when the thickness of the protective layer serving as the surface layer is large. Although various attempts have been made to obtain a photoconductor for positive charging as described above, there are many problems to be solved in terms of photosensitivity, memory phenomenon, occupational health and the like.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a pyrazine compound useful as a charge-transporting substance used in an electrophotographic photoreceptor, and a photosensitive layer containing a charge-generating substance and a charge-transporting substance on a conductive support. Provided is an electrophotographic photoreceptor provided with the pyrazine compound, which is characterized by using the pyrazine compound as a high-performance charge transporting material having good compatibility with a binder resin. The purpose is to do.

[0008]

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

[Chemical 1] {In the formula, X is = C (Y) (Z) or = N (C
N), Y and Z are H, a cyano group, COOR, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, or a substituted or unsubstituted pyridyl group (wherein R is
Represents a substituted or unsubstituted alkyl group, or a substituted or unsubstituted phenyl group. ) And W each represent an alkyl group, a halogen atom, an alkoxycarbonyl group, a phenyl group, a cyano group, or a nitro group. n
Represents an integer of 0 to 4. } According to the present invention, in an electrophotographic photoreceptor having a conductive support and a photosensitive layer provided thereon as an essential component,
There is provided an electrophotographic photoreceptor comprising the pyrazine compound represented by the general formula (I) in the photosensitive layer, and the photosensitive layer is composed of a charge generation layer and a charge transport layer, At least in the charge transport layer, the above general formula (I)
There is provided an electrophotographic photosensitive member characterized by containing a pyrazine compound represented by, further, the photosensitive layer is composed of at least a charge generating substance, a single layer containing a charge transporting substance as an essential component, There is provided an electrophotographic photoreceptor comprising the pyrazine compound represented by the general formula (I) as the charge transport material.

The present invention will be described in more detail below. In the general formula (I), the substituent of the phenyl or naphthyl group of Y, Z, and R is a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an alkyl group such as a t-butyl group, or methoxy. Group, or alkoxy group such as ethoxy group, halogen atom such as fluorine atom, chlorine atom or bromine atom, halogenated alkyl group such as trifluoromethyl group, alkoxycarbonyl group such as methoxycarbonyl group, substituted or unsubstituted phenoxy Examples thereof include a carbonyl group, a substituted or unsubstituted naphthoxycarbonyl group, an acyl group, a cyano group, and a nitro group.
Moreover, examples of the substituent of the alkyl group of 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, the ninhydrin compound (I
The pyrazine compound (VI) can be obtained by reacting V) with diaminomaleonitrile (V) by heating. The reaction is usually solvent-free, or 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 carried out in an aromatic solvent. The reaction temperature is room temperature to 150 ° C, preferably room temperature to 100 ° C.

Next, the pyrazine compound represented by the general formula (VI) and the 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 paratoluenesulfonic 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, or ammonium acetate, caustic soda, caustic potassium, or carbonic acid. Examples thereof include inorganic bases such as potassium, sodium methylate, sodium ethylate, and metal alcoholates such as potassium t-butoxide. The reaction is usually solvent-free,
It can be carried out with a halogen-based solvent such as dichloromethane or 2-dichloroethane, or a polar solvent such as methanol, ethanol, butanol, tetrahydrofuran, 1,4-dioxane or N-N-dimethylformamide.

Further, the pyrazine compound (VI) can be condensed with the bis (trimethylsilyl) carbodiimide (VIII) using the above-mentioned acid as a catalyst in the same solvent as described above to obtain the pyrazine compound (III). The 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 as an electronic device such as a solar cell or an organic EL device in the electronics field.

Next, the structure of the photoconductor of the present invention will be described with reference to the drawings. As the photoreceptor, for example, as shown in FIG. 1, a layer containing a charge generating substance and optionally a binder resin on a support 1 (a conductive support or a sheet on which a conductive layer is provided) (charge generating layer). ) 2 as a lower layer, containing a charge transport material and optionally a binder resin (charge transport layer)
3, a photosensitive layer 4 having a laminated structure having 3 as an upper layer, 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 photosensitive layer 6 containing a charge-generating substance, a charge-transporting substance and, if necessary, a binder resin may be provided. 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, either an inorganic substance or an organic substance can be used as long as it absorbs visible light and generates a free charge. For example, amorphous selenium, trigonal selenium, selenium-arsenic alloy, selenium-tellurium alloy, cadmium sulfide,
Inorganic substances such as cadmium selenide, cadmium sulfur selenide, mercury sulfide, lead oxide, lead sulfide, and amorphous silicon, or bisazo dyes, polyazo dyes, triarylmethane dyes, thiazine dyes, oxazine dyes, xanthene dyes Dyes, cyanine dyes, styryl dyes, pyrylium dyes, quinacridone dyes, indigo dyes, perylene dyes, polycyclic quinone dyes, bisbenzimidazole dyes, indanthrone dyes, squarylium dyes, anthraquinone dyes Examples include dyes and organic substances such as phthalocyanine dyes.

Examples of the binder resin usable in the photosensitive layer in the present invention include polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin,
Vinyl acetate resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicon resin, addition resin such as melamine resin, polyaddition resin, polycondensation resin, and repetition of these resins Copolymer resins containing two or more units, such as vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymer resins, and other insulating resins, as well as poly-N-vinylcarbazole. Polymer organic semiconductors such as

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

In the case where the photoconductor according to the present invention is formed with a laminated structure of a charge generation layer and a charge transport layer, that is, in the case of FIGS. 1 and 2, the charge generation layer is formed by vacuumizing a charge generation substance on a conductive support. It can be formed by vapor deposition, or by coating and drying a suitable solvent alone or dissolved or dispersed with a suitable binder resin, and drying. When the charge-generating layer is formed by dispersing the charge-generating substance, the charge-generating substance is preferably a powder having an average particle diameter of 2 μm or less, preferably 1 μm or less. That is, if the particle size is too large, the dispersion in the layer becomes poor, and the particles partially project on the surface and the surface smoothness deteriorates. Toner filming phenomenon tends to occur due to particles adhering. However, if the above-mentioned particle size is too small, it tends to agglomerate rather, the resistance of the layer increases, the crystal defects increase and the sensitivity and repeatability deteriorate, or there is a limit on fineness. The lower limit of the diameter is preferably 0.01 μm.

The charge generation layer can be provided by the following method. That is, the charge generating substance is made into fine particles in a dispersion medium by a ball mill, a homomixer, etc.,
It is a method of applying a binder resin and mixing and dispersing to obtain a dispersion liquid. In this method, if the particles are dispersed under the action of ultrasonic waves, uniform dispersion is possible. In the charge generation layer, the proportion of the charge generation substance contained in the binder resin is 20 to 200 parts by weight with respect to 100 parts by weight of the binder resin. The film thickness of the charge generation layer formed as described above is preferably 0.1 to 10 μm, particularly preferably 0.5 to 5 μm.

Next, the charge transport layer of the present invention is a charge generation layer by a method in which the above pyrazine compound as a charge transport substance is dissolved or dispersed in a suitable solvent alone or together with a suitable binder resin and then dried. The same as the above. 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, 1,
1,2-trichloroethylene, tetrahydrofuran, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate and the like can be mentioned. In this charge transport layer,
The ratio of the charge transport material contained in the binder resin is 20 to 2 with respect to 100 parts by weight of the binder resin.
It is used in a proportion 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
It is 30 μm.

Next, when the photoconductor 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 generation material is used in a proportion of 20 to 200 parts by weight, and the charge transport material is used in a proportion of 20 to 200 parts by weight. The film thickness of the single-layer photosensitive member is 7 to 50 μm, more preferably 10 to 30 μm.

The intermediate layer functions as an adhesive layer or a barrier layer, and in addition to the above binder resin, for example, polyvinyl alcohol, ethyl cellulose,
Resins such as carboxymethyl cellulose, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, casein, N-alkoxymethyl nylon as they are, or those in which tin oxide or indium is dispersed, Aluminum oxide, zinc oxide,
Alternatively, a vapor deposition film of silicon oxide or the like is used. The thickness of the intermediate layer is preferably 1 μm or less. As the material used for the protective layer, it is suitable 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 is appropriately oxygen, nitrogen, halogen, or III in the periodic table as needed.
It may contain a group or group V atom.

[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 and refluxed in 1 for 2 hours. After the reaction, the mixture was allowed to cool to room temperature, the precipitated crystals were separated by filtration, and the obtained crude target substance was recrystallized from ethanol to obtain a pure target substance 7.1.
6 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 Formula (II), Compound No. I-110] 2.32 g of the compound obtained in Synthesis Example 1 and 4.33 g of commercially available malonate-n-dibutyl malonate were added to 80 m of dichloromethane.
It was dissolved in 1 l and 3.79 g of titanium tetrachloride was added to 1 while stirring under ice cooling.
The solution was added dropwise over 0 minutes, and N-methylmorpholine 2.0 was added.
2 g was added dropwise over 10 minutes. After 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. The chloroform layer was dried over magnesium sulfate, the solvent was distilled off, and the residue was subjected to column chromatography using chloroform as a developing solvent, and the obtained crude target substance was recrystallized from ethanol to obtain a pure target substance. 1.48 g of the product was obtained. Melting point: 147.9 to 149.0 ° C. Further, an infrared absorption spectrum diagram 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 elemental analysis results of the compounds obtained as described above.

[0047]

[Table 4]

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

[Chemical 2] On the charge generation layer thus obtained, 6 parts of the exemplified compound (Compound No. I-110), 10 parts of a polycarbonate resin (K-1300: manufactured by Teijin Chemicals), methyl phenyl silicon (KF50-100 cps: Shin-Etsu Chemical). Made)
A coating solution having a composition of 0.002 parts and tetrahydrofuran (94 parts) was prepared and cast-coated with a doctor blade to form a charge-transporting layer having a thickness of 20.0 μm after drying. Aluminum electrode / charge generation A laminated electrophotographic photoreceptor (photoreceptor No. 1) composed of a layer / charge transport layer was prepared.

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

Example 5 The same as Example 1 except that 6 parts of the trisazo dye represented by the following chemical formula (P-2) was used in place of 5 parts of the bisazo dye represented by the following chemical formula (P-1). The charge generation layer was prepared by the method.

[Chemical 3] On the charge generation layer thus obtained, 6 parts of the exemplified compound (Compound No. I-110), 10 parts of a polycarbonate resin (K-1300: manufactured by Teijin Chemicals), methyl phenyl silicon (KF50-100 cps: Shin-Etsu Chemical). Made)
A coating solution consisting of 0.002 parts and 94 parts of tetrahydrofuran was prepared, and a charge transport layer having a film thickness after drying of 20.0 μm was formed in the same manner as in Example 1, and aluminum electrode / charge generation layer / charge was formed. A laminated electrophotographic photosensitive member (photosensitive member No. 5) including a transport layer was prepared.

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

Example 9 5 parts of x-type phthalocyanine (P-3), 5 parts of polyvinyl butyral resin (S-Rex BLS: Sekisui Chemical Co., Ltd.),
And 90 parts of tetrahydrofuran were dispersed in a ball mill for 12 hours, and then tetrahydrofuran was added so as to have a dispersion liquid concentration of 2% by weight and redispersed to prepare a coating liquid. The prepared dispersion liquid was vapor-deposited with aluminum to 100 μm.
The polyester film having a thickness of m was cast and coated 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, coating of a formulation comprising 6 parts of the exemplified compound (Compound No. I-110), 10 parts of a polycarbonate resin (K-1300: manufactured by Teijin Chemicals), and 94 parts of tetrahydrofuran. A layered electrophotographic photoconductor in which a liquid is prepared and cast-coated with a doctor blade to form a charge transport layer having a film thickness after drying of 20.0 μm, which is composed of an aluminum electrode / charge generation layer / charge transport layer A body (photoreceptor No. 9) was formed.

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

The electrophotographic photosensitive member obtained as described above was subjected to +6 KV corona charging using an electrostatic copying paper tester (SP-42: Kawaguchi Denki Seisakusho), and after being positively charged, for 20 seconds. Left in the dark, the surface potential V at that time
o was measured, and then light irradiation was performed using a tungsten lamp so that the illuminance on the surface was 40 lux, and the half-exposure amount E1 / 2 (lux · sec) was measured. The results are shown in Table 5.

[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 a donor compound (D-1) 0.9.
g, 0.6 g of the exemplified compound (Compound No. 36), and 0.3 g of a 1 wt% tetrahydrofuran solution of silicon oil (KF50: manufactured by Shin-Etsu Chemical Co., Ltd.) were weighed in a ball mill pot and ball-milled for 24 hours to prepare a coating liquid. The coating liquid thus prepared was cast and coated on a 100 μm-thick polyester film on which aluminum was vapor-deposited by a doctor blade to prepare a single-layer type electrophotographic photoreceptor having a film thickness after drying of about 20 μm.

[Chemical 4]

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

[Table 4]

[0059]

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

[Brief description of 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 an electrophotographic photosensitive member according to the present invention, in which an electrophotographic photosensitive member having the cross section shown in FIG.

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

FIG. 4 is an infrared absorption spectrum diagram of a compound of general formula (VI) (n = 0) obtained in Synthesis Example 1.

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

[Explanation of symbols]

 1 Support 2 Charge Generation Layer 3 Charge Transport Layer 4 Photoreceptor Layer (Layered Structure) 5 Protective Layer 6 Photoreceptor Layer (Single Layered Structure)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akio Kojima 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (4)

[Claims] 1. A pyrazine compound represented by the following general formula (I). [Chemical 1] {In the formula, X is = C (Y) (Z) or = N (C
N), Y and Z are H, a cyano group, COOR, a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, or a substituted or unsubstituted pyridyl group (wherein R is
Represents a substituted or unsubstituted alkyl group, or a substituted or unsubstituted phenyl group. ) And W each represent an alkyl group, a halogen atom, an alkoxycarbonyl group, a phenyl group, a cyano group, or a nitro group. 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 constituent, wherein the pyrazine compound represented by the general formula (I) according to claim 1 is contained in the photosensitive layer. An electrophotographic photosensitive member comprising: 3. The photosensitive layer comprises a charge generation layer and a charge transport layer, and at least the pyrazine compound represented by the general formula (I) according to claim 1 is contained in the charge transport layer. The electrophotographic photosensitive member according to claim 2. 4. The photosensitive layer comprises at least a charge generating substance,
A single layer comprising a charge transport substance as an essential component, and the pyrazine compound represented by the general formula (I) according to claim 1 being contained as the charge transport substance. Electrophotographic photoreceptor.