JPH08151371A - Oxadiazole derivative and photographic photoreceptor using the same - Google Patents

Abstract

PURPOSE: To obtain a new compound having good solubility to solvents and compatibility with binder resins, excellent in matching with electron charge- generating agents, thereby excellent in electron-transporting property in low electric field and capable of providing an electrophotographic photoreceptor having high sensitivity as an electron transporting agent. CONSTITUTION: This compound is expressed by a compound of formula I [R<1> and R<2> are each H, alkyl, etc.; (n), (m), (p) and (q) are each 0-2, with the proviso that (n) and (m) are simultaneously 0], e.g. a compound of formula II. The compound is obtained by reacting, e.g. a benzoic acid derivative of formula III (R3 is an alkoxy or a halogen) with hydrazine in a solvent such as ethanol to afford a benzhydrazide, reacting the compound with a benzoic acid derivative identical with or different from the benzoic acid derivative of formula III to afford a dibenzhydrazide of formula IV, reacting the compound in a solvent such as phosphoryl chloride at 70-140 deg.C for 1-18hr to carry out cyclization reaction by intramolecular condensation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxadiazole derivative and an electrophotographic photoreceptor using the same, more specifically, an electron transfer material for an electrophotographic organic photoreceptor used in a copying machine, a laser printer or the like. And an oxadiazole derivative preferably used as.

[0002]

2. Description of the Related Art Electrophotographic photoreceptors made of various materials are used in image forming apparatuses such as copying machines using the Carlson process. One is an inorganic photoreceptor using an inorganic material such as selenium in the photosensitive layer, and the other is an organic photoreceptor using an organic material in the photosensitive layer. Extensive research has been conducted because organic photoreceptors have many advantages such as being inexpensive and having high productivity as compared with inorganic photoreceptors and being non-polluting.

As the organic photoconductor, there are many so-called function-separated type organic photoconductors in which a charge generation layer and a charge transport layer are laminated, that is, laminated photoconductors, but a charge generation agent and a charge transport agent are used as the photoconductive layer. A single-layer type organic photoconductor dispersed therein is also known. Charge transport agents used in these photoreceptors are required to have high carrier mobility, but most charge transport agents having high carrier mobility have hole transporting properties. Therefore, it is practically limited to the negative charging type laminated organic photoreceptor having the charge transport layer as the outermost layer from the viewpoint of mechanical strength. However, since the negative charge type organic photoconductor uses negative corona discharge, a large amount of ozone is generated, and thus there are problems such as pollution of the environment and deterioration of the photoconductor.

Therefore, in order to eliminate such drawbacks, the use of an electron transfer agent as a charge transfer agent has been studied, and in JP-A-1-206349, a compound having a diphenoquinone structure is electrophotographic. It has been proposed to use it as an electron transfer material for photoreceptors. However, in general, conventional electron transfer agents containing diphenoquinones have poor compatibility with the binder resin and have a long hopping distance, so that electron transfer in a low electric field does not easily occur. Therefore, the electrophotographic photoreceptor containing the conventional electron transfer material has a drawback that the residual potential is considerably high and the sensitivity is low.

In order to solve such a drawback, JP-A-4-46350 and JP-A-5-150498 propose to use a specific oxadiazole derivative as an electron transfer agent. Although these oxadiazole derivatives are more compatible with the binder resin than the above diphenoquinone derivatives, they have insufficient electron transporting ability, and thus a high-sensitivity photoreceptor cannot be obtained.

A main object of the present invention is to provide a novel oxadiazole derivative having an excellent electron transporting ability. Another object of the present invention is to provide a single-layer type and a multi-layer type electrophotographic photoconductor in which the residual potential is suppressed to a low level and which exhibits excellent sensitivity.

[0007]

Means and Actions for Solving the Problems The oxadiazole derivative of the present invention has the formula (1):

[0008]

Embedded image

(Wherein R ¹ and R ² are the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and n, m, p and q are the same or different and are an integer of 0 to 2). However, n and m must not be 0 at the same time.) The oxadiazole derivative (1) of the present invention has a more broad π than a conventional diphenoquinone derivative.
Since it has an electron conjugated system, it has a high electron transporting ability. Further, this derivative (1) is different from the above-mentioned conventional oxadiazole derivative in that by introducing a nitro group into the benzene ring, the solubility in a solvent and the compatibility with a binder resin are good, It becomes excellent in matching with the charge generating agent, the electrons are smoothly injected, and the electron transporting property is excellent especially in a low electric field.

The nitro group preferably has at least one substituent on each of the two benzene rings. That is, n and m in the general formula (1) are 1 or 2
Should be an integer. In addition, the oxadiazole derivative of the present invention preferably has an asymmetric structure in order to further improve the solubility and compatibility and enhance the sensitivity of the electrophotographic photoreceptor. Specifically, (1) groups R ¹ and R ² are different from each other, (2) n and m are different from each other, (3) R ¹
And varying the substitution position and the number of substitutions of R ^2, form an asymmetric structure by such as by replacing (4) varying the substitution position of the nitro group in both benzene ring, (5) one of the benzene ring only nitro group can do.

The electrophotographic photoreceptor of the present invention comprises an electroconductive substrate and an organic photosensitive layer provided on the electroconductive substrate, wherein the organic photosensitive layer serves as an electron transporting agent represented by the general formula (1). It is characterized by containing an azole derivative. Since the electrophotographic photosensitive member of the present invention contains the oxadiazole derivative (1), the electron transporting ability is remarkably improved, and as a result, the ratio of electrons and holes to be recombined is reduced, The apparent charge generation efficiency approaches the actual value, and the sensitivity of the photoconductor is improved. In addition, the residual potential of the photoconductor also becomes low, and the stability and durability upon repeated exposure are improved.

The organic photosensitive layer contains an electron-accepting compound having an oxidation-reduction potential of -0.8 to -1.3 V, in addition to the above-mentioned electron transfer agent, in order to reduce the number of electrons from the charge generating agent. This is preferable because the drawing effect is enhanced. Each group represented by the general formula (1) will be specifically described. Examples of the alkyl group include alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, t-butyl, pentyl and hexyl groups.

Examples of the alkoxy group include alkoxy groups having 1 to 6 carbon atoms such as methoxy, ethoxy, propoxy, t-butoxy, pentyloxy and hexyloxy groups. As a halogen atom, chlorine,
Examples include bromine, fluorine and iodine. The derivatives represented by the general formula (1) include, for example, the following compounds. Of these, formulas (1-1) to (1-5) represent compounds having a symmetric structure, and formulas (1-6) to (1-12) represent compounds having an asymmetric structure.

[0014]

[Chemical 4]

[0015]

Embedded image

[0016]

[Chemical 6]

The oxadiazole derivative (2) of the present invention is
For example, it can be synthesized as shown below.

[0018]

[Chemical 7]

(Wherein R ¹ , R ² , p, q, m and n
Is the same as above, and R ³ and R ⁴ are an alkoxy group or a halogen atom. The benzoic acid derivative represented by the general formula (10) is an ester or an acid chloride. The benzoic acid derivative (10) is reacted with hydrazine in a suitable solvent to obtain a benzhydrazide derivative represented by the general formula (11). As the solvent,
Examples include lower alcohols such as ethanol and pyridine.

The benzhydrazide derivative (11) is reacted with a benzoic acid derivative (12) which is the same as or different from the benzoic acid derivative (10) to obtain a dibenzhydrazide derivative represented by the general formula (13). The reaction may be performed in a suitable solvent at a temperature of 40 to 130 ° C. for 6 to 24 hours. Then, the dibenzhydrazide derivative (13) is allowed to undergo a ring-closing reaction by intramolecular condensation to give the oxadiazole derivative (1) of the present invention.
Get. The reaction may be performed in a solvent such as phosphoryl chloride at a temperature of 70 to 140 ° C. for 1 to 18 hours.

The electrophotographic photosensitive member of the present invention is roughly classified into a single layer type and a laminated type. The single-layer type electrophotographic photoconductor is one in which an organic photosensitive layer is provided on a conductive substrate, and the organic photosensitive layer is a binder resin containing at least a charge generating agent and a hole transporting agent, and An oxadiazole derivative represented by the formula (1) is contained as an electron transfer agent. In this single-layer type electrophotographic photosensitive member, the residual potential of the photosensitive member is greatly reduced, and the sensitivity can be improved. The single-layer type photoreceptor of the present invention can be applied to both positive charging and negative charging, but it is particularly preferable to use the positive charging type.

When the organic photosensitive layer of the single-layer type electrophotographic photosensitive member contains an electron-accepting compound having an oxidation-reduction potential of -0.8 to -1.3 V, the electron withdrawing from the charge generating agent is removed. It can be performed efficiently, and the sensitivity of the photoconductor is further improved. On the other hand, the multilayer electrophotographic photoreceptor of the present invention is one in which at least a charge generation layer and a charge transport layer are provided in this order on a conductive substrate, and the charge transport layer has the above general formula (1) as an electron transport agent. ) The oxadiazole derivative represented by

This electrophotographic photosensitive member is used as a positive charging type, and the residual potential is greatly reduced, and the sensitivity can be improved. In order to smoothly transfer electrons from the charge generation layer to the charge transport layer, the charge generation layer also has the general formula (1)
It is preferable to contain an oxadiazole derivative represented by

Further, in a laminated electrophotographic photoreceptor in which at least a charge generation layer and a charge transport layer are provided in this order on a conductive substrate, the charge transport layer is represented by the general formula (1) as an electron transport agent. An electron-accepting compound having an oxidation-reduction potential of -0.8 to -1.3 V may be contained in the charge generation layer, while containing an oxadiazole derivative. The redox potential is measured using the following materials by a three-electrode type cyclic voltammetry.

Electrode: working electrode (glassy carbon electrode), counter electrode (platinum electrode) Reference electrode: silver nitrate electrode (0.1 mol / liter AgNO)
₃ - acetonitrile) Measurement solution electrolyte: perchlorate tetra -n- butylammonium 0.1 mol analyte: electron transporting agent 0.001 mol solvent: formulated with CH ₂ Cl ₂ 1 liter or more materials measurement solution Prepare.

Calculation of redox potential: As shown in FIG.
The relationship between the index voltage (V) and the current (μA) is obtained, E ₁ and E ₂ shown in the figure are measured, and the redox potential is obtained by the following calculation formula. Redox potential = (E ₁ + E ₂ ) / 2 (V) The compound represented by the general formula (1) in the present invention has good solubility in a solvent and compatibility with a binder resin, and Excellent matching with the charge generating agent, smooth injection of electrons, and excellent electron transporting property especially in a low electric field.

Therefore, the single-layer type positive charging photoreceptor of the present invention is
The electrons released from the charge generating agent in the exposure step are smoothly injected into the electron transfer agent represented by the general formula (1), and then the electrons are transferred to and from the photosensitive layer by the transfer of electrons between the electron transfer agents. Then, the positive charge (+) charged on the surface of the photosensitive layer is canceled. On the other hand, holes (+) are injected into the hole transport material, move to the surface of the conductive substrate without being trapped in the middle, and cancel the negative charge (-) on the surface of the conductive substrate. In this way, the sensitivity of the positive charging type photoconductor is considered to be improved. When the single-layer type photoreceptor is used with negative charging, the sensitivity is similarly improved only by reversing the direction of charge transfer.

Further, in the laminated positive charging photoreceptor of the present invention,
Electrons released from the charge generating agent in the charge generating layer in the exposure step are smoothly injected into the electron transferring agent represented by the general formula (1) in the charge transferring layer, and then the electrons between the electron transferring agents are changed. Upon transfer, the electrons move in the charge transport layer, reach the surface of the photosensitive layer, and cancel the positive charge (+) charged in advance on the surface of the photosensitive layer. On the other hand, holes (+) move directly from the charge generation layer to the surface of the conductive substrate, and cancel the negative charge (-) on the surface of the conductive substrate. It is considered that the sensitivity of the layered positively charged photoreceptor is improved in this way.

The charge-generating agent that absorbs light upon exposure to the photosensitive member produces ion pairs [holes (+) and electrons (-)]. In order for the generated ion pairs to become free carriers and effectively cancel the surface charge, it is preferable that the ion pair recombine and disappear. When an electron-accepting compound having an oxidation-reduction potential of −0.8 to −1.3 V is present, LUMO (means the highest energy level in the molecular orbitals occupied by electrons in the molecule). , The excited electron is usually an electron of this level.) Since the energy level of the electron is lower than that of the charge generating agent, the electron moves to the electron-accepting compound during the generation of the ion pair, and the ion pair becomes the carrier. It becomes easy to separate into. That is, the electron-accepting compound acts on the charge generation to improve the generation efficiency.

On the other hand, in order to have high sensitivity, it is also necessary that carrier traps due to impurities do not occur when free carriers move. Usually, a trap due to a small amount of impurities exists in the moving process of the free carrier, and the free carrier moves while repeating trap-detrap. Therefore, when the free carriers fall to a level where they cannot be untrapped, they become carrier traps and their movement is stopped.

When an electron-accepting compound having an oxidation-reduction potential of higher than -0.8 V is used, the separated free carriers are dropped to a level that cannot be detrapped, resulting in carrier traps. On the contrary, the redox potential is −
LUM for electron-accepting compounds less than 1.3 V
The energy level of O becomes higher than that of the charge generating agent, and when the ion pair is generated, the electrons do not move to the electron accepting compound,
It is considered that this does not lead to improvement in charge generation efficiency.

As the hole-transporting agent, conventionally known hole-transporting substances are used, for example, oxadiazole such as 2,5-di (4-methylaminophenyl) and 1,3,4-oxadiazole. Compounds, styryl compounds such as 9- (4-diethylaminostyryl) anthracene, carbazole compounds such as polyvinylcarbazole, organic polysilane compounds, pyrazoline compounds such as 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline, Nitrogen-containing cyclic compounds such as hydrazone compounds, triphenylamine compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, and triazole compounds, Such as condensed polycyclic compounds .

These charge transport materials may be used alone or in admixture of two or more. Further, when using a charge transport material having film-forming properties such as polyvinylcarbazole, the binder resin is not always necessary. In the present invention, among the hole transporting agents, the ionization potential is 4.8 to 5.6 eV.
It is preferable to use one having an electric field strength of 3 × 10 ⁵ V
Those having a mobility of 1 × 10 ⁻⁶ cm ² / V · sec or more in / cm are particularly preferable. Specifically, alkyl-substituted triphenylamine derivatives are preferable.

The ionization potential of the hole-transporting agent is measured by using an atmospheric photoelectron analyzer (AC-1 manufactured by Riken Keiki Co., Ltd.) as in the electron-transporting agent. In the present invention, by using a hole transfer agent having an ionization potential within the above range, the residual potential can be further lowered and the sensitivity can be improved. The reason is not clear, but it is considered as follows.

That is, the easiness of injecting the charge from the charge generating agent into the hole transferring material is closely related to the ionization potential of the hole transferring material, and the ionization potential of the hole transferring material is higher than the above range. If it is large, the degree of charge injection from the charge generating agent to the hole transporting agent will be low, or the degree of transfer of holes between the hole transporting agents will be low, resulting in a decrease in sensitivity. Is recognized.

On the other hand, in a system in which a hole transfer material and an electron transfer material coexist, it is necessary to pay attention to the interaction between them and more specifically to the formation of a charge transfer complex. When such a complex is formed between the two, recombination occurs between the holes and the electrons, and the mobility of the charge is lowered as a whole. When the ionization potential of the hole transfer material is smaller than the above range, the tendency to form a complex with the electron transfer material increases, and electron-hole recombination occurs, resulting in an apparent quantum yield. Is likely to decrease, resulting in a decrease in sensitivity.

Therefore, a bulky substituent is introduced into the oxadiazole derivative represented by the general formula (1), and the steric hindrance thereof suppresses the formation of a complex with the hole transfer agent. Is preferred. The hole transporting agent used in the present invention is not particularly limited, but for example, 1,1-bis (4-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene, N,
N'-bis (2,4-dimethylphenyl) -N, N'-
Diphenylbenzidine, 3,3'-dimethyl-N, N,
N ', N'-tetrakis-4-methylphenyl (1,
1'-biphenyl) -4,4'-diamine, N-ethyl-3-carbazolylaldehyde-N, N'-diphenylhydrazone, 4- [N, N-bis (p-toluyl) amino] -β- Examples include phenyl stilbene.

The electron-accepting compound is not particularly limited as long as it has an electron-accepting property and an oxidation-reduction potential of -0.8 to -1.3 V, and examples thereof include benzoquinone compounds and naphthoquinone compounds. Anthraquinone type, diphenoquinone type, malononitrile, thiopyran type compound, 2,
4,8-trinitrothioxanthone, 3,4,5,7-
Examples thereof include fluorenone compounds such as tetranitro-9-fluorenone, dinitroanthracene, dinitroacridine, nitroanthraquinone and dinitroanthraquinone. Of these, the diphenoquinone type has a quinone type oxygen atom excellent in electron-accepting property bonded to the end of the molecular chain, and since there is a conjugated double bond over the entire long molecular chain, the transfer of electrons within the molecule also occurs. It is particularly preferable because it has the advantage that it is easy and the transfer of electrons is easy. Further, each electron-accepting compound described above contributes to the generation of charges.

Examples of the benzoquinone compounds include p-benzoquinone, 2,6-dimethyl-p-benzoquinone and 2,6-di-t-butyl-p-benzoquinone. Further, as the diphenoquinone compound,
Examples include derivatives represented by the following general formulas (4) to (7).

[0040]

Embedded image

[0041]

[Chemical 9]

(In each formula, R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷
And R ¹⁸ are the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, a cycloalkyl group, or an amino group which may have a substituent. ) Examples of the alkyl group include alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, t-butyl, pentyl and hexyl groups, and examples of the alkoxy group include methoxy, ethoxy and propoxy groups. ,
An alkoxy group having 1 to 6 carbon atoms such as t-butoxy, pentyloxy and hexyloxy groups, an aryl group such as a phenyl group and a naphthyl group, and an aralkyl group such as benzyl, benzhydryl, trityl and phenethyl. Groups, etc., as the cycloalkyl group,
Examples thereof include cycloalkyl groups having 3 to 6 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. The amino group which may have a substituent includes, for example, an amino group, monomethylamino, dimethylamino, monoethylamino,
Examples thereof include a diethylamino group.

Specific examples of the diphenoquinone compounds represented by the formulas (4) to (7) include, for example, 3,5-dimethyl-
3 ', 5'-dit-butyldi-4,4'-diphenoquinone, 3,3'-dimethyl-5,5'-dit-butyl-
4,4'-diphenoquinone, 3,5'-dimethyl-3,
Examples thereof include 5'-di-t-butyl-4,4'-diphenoquinone. The diphenoquinone-based compound having these substituents is preferable because the symmetry of the molecule is low, the interaction between the molecules is small, and the solubility is excellent. Also,
Examples of the diphenoquinone compound represented by the formula (4) include 3,3 ', 5,5'-tetramethyl-4,4'-diphenoquinone, 3,3', 5,5'-tetraethyl-
4,4'-diphenoquinone, 3,3 ', 5,5'-tetra-t-butyl-4,4'-diphenoquinone and the like can be mentioned. These diphenoquinone compounds can be used alone or in combination of two or more.

Examples of the charge generating agent used in the present invention include selenium, selenium-tellurium, amorphous silicon, pyrylium salts, azo pigments, ansanthuron pigments, phthalocyanine pigments, perylene pigments, naphthalocyanine pigments, Examples thereof include indigo pigments, triphenylmethane pigments, slene pigments, toluidine pigments, pyrazoline pigments, quinacridone pigments and dithioketopyrrolopyrrole pigments. These charge generating agents may be used alone or in combination of two or more so as to have an absorption wavelength in a desired region. At that time, in connection with the use of a hole transfer agent having an ionization potential of 4.8 to 5.6 eV, a charge generation agent having an ionization potential balanced with the hole transfer agent, specifically, Has an ionization potential of 4.8 to 6.0 eV, particularly 5.0 to 5.
Use of the one in the range of 8 eV reduces the residual potential,
Desirable for improving sensitivity. Examples of particularly suitable charge generating agents include phthalocyanine-based pigments such as X-type metal-free phthalocyanine and oxotitanyl phthalocyanine, or perylene-based pigments.

Of these, the phthalocyanine pigment is 70
It is suitable as a charge generating material for a photoconductor having sensitivity in a wavelength region of 0 nm or more. That is, since the phthalocyanine-based pigment is excellent in matching with the compound (electron transfer agent) represented by the general formula (1), the electrophotographic photoreceptor using both of them has high sensitivity in the above wavelength range. Therefore, it can be suitably used for an image forming apparatus of a digital optical system using a light source having a wavelength of 700 nm or more.

Further, as the perylene pigment, a general formula:

[0047]

[Chemical 10]

(In the formula, R ^a , R ^b , R ^c and R ^d are the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group or an aryl group.) A compound represented by the following formula is preferably used. . Examples of the alkyl group, alkoxy group and aryl group include the same groups as described above. This perylene-based pigment is suitable as a charge generating material for a photoreceptor having sensitivity in the visible region. That is, since the perylene-based pigment (3) is excellent in matching with the compound (electron transfer agent) represented by the general formula (1), the electrophotographic photoreceptor using both of them has high sensitivity in the visible region. Therefore, it can be suitably used for an image forming apparatus of an analog optical system using a light source having a wavelength in the visible region.

As the binder resin for dispersing the above components, various resins conventionally used in organic photosensitive layers can be used, for example, a styrene polymer,
Styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic copolymer, styrene-acrylic acid copolymer, polyethylene, ethylene-vinyl acetate copolymer, chlorinated polyethylene, poly Vinyl chloride, polypropylene, ionomer, vinyl chloride-vinyl acetate copolymer, polyester,
Alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin,
Thermoplastic resin such as polyether resin, polyester resin, silicone resin, epoxy resin, phenol resin,
Examples thereof include urea resins, melamine resins, other crosslinkable thermosetting resins, and photocurable resins such as epoxy acrylate and urethane-acrylate. These binder resins can be used alone or in combination of two or more. Suitable resins are styrene polymers, acrylic polymers, styrene-acrylic copolymers, polyesters, alkyd resins, polycarbonates, polyarylates and the like.

In order to obtain a single-layer type electrophotographic photosensitive member, a predetermined electron transporting agent is dissolved or dispersed in a suitable solvent together with a charge generating agent, a hole transporting agent, a binder resin and the like to apply a coating solution. It may be applied on the conductive substrate by means such as the above and dried. In order to obtain a laminated type electrophotographic photoreceptor, first, a charge generation layer containing a charge generation agent is formed on a conductive substrate by means such as vapor deposition or coating, and then an electron transfer agent is formed on this charge generation layer. A coating liquid containing a binder resin and a binder resin may be applied by means such as coating and dried to form the charge transport layer.

In the case of a single-layer type photoreceptor, the binder resin 10
The charge generating agent is added in an amount of 0.1 to 50 parts by weight, preferably 0.5 to 30 parts by weight, and the electron transporting agent is 5 to 100 parts by weight, preferably 10 to 80 parts by weight, based on 0 parts by weight. It is mixed in the ratio of. Further, the hole transfer agent is added in an amount of 5 to 500 parts by weight, preferably 25 to 200 parts by weight. Further, it is suitable that the total amount of the hole transfer agent and the electron transfer agent is 20 to 500 parts by weight, preferably 30 to 200 parts by weight, based on 100 parts by weight of the binder resin. When the single-layer type photosensitive layer contains an electron-accepting compound, the electron-accepting compound is added in an amount of 0.1 to 100 parts by weight of the binder resin.
It is suitable to add 40 parts by weight, preferably 0.5 to 20 parts by weight.

The thickness of the single-layer type photosensitive layer is 5 to 100.
μm, preferably 10 to 50 μm. In the multi-layer type photoreceptor, the charge generating agent and the binder resin constituting the charge generating layer can be used in various ratios, but the charge generating agent is added in an amount of 5 to 1000 with respect to 100 parts by weight of the binder resin. It is suitable to blend in a weight ratio of 30 to 500 parts by weight. When the charge-generating layer contains an electron-accepting compound, the electron-accepting compound is contained in an amount of 0.1 to 40 parts by weight, preferably 0.5 to 20 parts by weight, based on 100 parts by weight of the binder resin.
It is suitable to blend in parts by weight. When the charge generation layer contains the oxadiazole derivative (1), the derivative (1) is added in an amount of 0.5 to 5 with respect to 100 parts by weight of the binder resin.
It is suitable to add 0 parts by weight, preferably 1 to 40 parts by weight.

The electron-transporting agent and the binder resin constituting the charge-transporting layer can be used in various proportions within the range that does not hinder the transport of charge and the range that does not crystallize. In order to easily transport the generated charge, 10 to 10 parts by weight of the electron transfer agent may be added to 100 parts by weight of the binder resin.
It is suitable to mix it in an amount of 500 parts by weight, preferably 25 to 100 resin. When the charge transport layer contains an electron-accepting compound, the electron-accepting compound is added to the binder resin 10
0.1 to 40 parts by weight, preferably 0.
It is suitable to add 5 to 20 parts by weight.

The thickness of the laminated photosensitive layer is about 0.01 to 5 μm, preferably 0.1 to 3 μm for the charge generation layer.
The charge transport layer has a thickness of 2 to 100 μm, preferably 5 to 50 μm. In the case of a single-layer type photoreceptor, between the conductive base and the photosensitive layer, and in the case of the multilayer type photoreceptor, between the conductive base and the charge generation layer, the conductive base and the charge transport layer. Between or between the charge generation layer and the charge transport layer,
A barrier layer may be formed in a range that does not impair the characteristics of the photoreceptor. Further, a protective layer may be formed on the surface of the photoconductor.

Various additives known per se, such as an antioxidant, a radical scavenger, and a singlet quencher, are added to each of the single-layer type and laminated type photosensitive layers, as long as they do not adversely affect the electrophotographic characteristics. A deterioration inhibitor such as an ultraviolet absorber, a softening agent, a plasticizer, a surface modifier, a bulking agent, a thickener, a dispersion stabilizer, a wax, an acceptor, a donor and the like can be added.

In order to improve the sensitivity of the photosensitive layer,
For example, known sensitizers such as terphenyl, halonaphthoquinones and acenaphthylene may be used in combination with the charge generating agent.
In addition to the compound represented by the above general formula, other conventionally known electron transfer agents may be contained in the photosensitive layer. Examples of such electron transfer agents include benzoquinone-based, diphenoquinone-based, malononitrile, thiopyran-based compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone, 3,4,5,7-tetranitro-9-fluorenone and the like. Fluorenone compounds, dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride,
Examples thereof include maleic anhydride and dibromomaleic anhydride.

As the conductive substrate used in the photoreceptor of the present invention, various conductive materials can be used. For example, aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium. , Cadmium, titanium,
Examples include simple metals such as nickel, palladium, indium, stainless steel, and brass, plastic materials in which the above metals are vapor-deposited or laminated, and glass coated with aluminum iodide, tin oxide, indium oxide, or the like.

The conductive substrate may be in the form of a sheet, a drum or the like, as long as the substrate itself has conductivity or the surface of the substrate has conductivity. Further, it is preferable that the conductive substrate has sufficient mechanical strength when used. The photosensitive layer according to the present invention is manufactured by coating a coating solution prepared by dissolving or dispersing a resin composition containing each of the above components in a solvent on a conductive substrate and drying the coating solution.

That is, the charge generating agent, charge transporting agent, binder resin and the like exemplified above are used together with an appropriate solvent by a known method such as a roll mill, a ball mill, an attritor, a paint shaker or an ultrasonic disperser. The coating liquid may be prepared by dispersing and mixing, and the coating liquid may be coated and dried by a known means. As the solvent for forming the coating liquid, various organic solvents can be used, for example, alcohols such as methanol, ethanol, isopropanol and butanol, aliphatic hydrocarbons such as n-hexane, octane and cyclohexane, benzene, Aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, carbon tetrachloride and chlorobenzene, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, acetone, methyl ethyl ketone, cyclohexanone, etc. Examples thereof include ketones, esters such as ethyl acetate and methyl acetate, dimethylformaldehyde, dimethylformamide, dimethylsulfoxide and the like. These solvents can be used alone or in combination of two or more.

Further, in order to improve the dispersibility of the charge transporting material or the charge generating material and the smoothness of the surface of the photosensitive layer, a surfactant, a leveling agent, etc. may be used.

[0061]

EXAMPLES Hereinafter, the oxadiazole derivative of the present invention and the electrophotographic photoreceptor using the same will be described with reference to Synthesis Examples, Examples and Comparative Examples. Synthesis Example 1 (Synthesis of Exemplified Compound 1-1) (I)

[0062]

[Chemical 11]

The inside of a 300-ml three-necked flask was replaced with argon, and 19.5 g (0.1 mol) of ethyl p-nitrobenzoate (a) and 50 ml of dry ethanol were put into this, and the mixture was heated under reflux. Add to this hydrazine hydrate 10.5
ml was slowly added dropwise using a dropping funnel. After refluxing for 14 hours, hydrazine hydrate and ethanol were distilled off, the obtained solid was added to ethanol and stirred, and crystals were filtered and dried to obtain p-nitrobenzhydrazide (b) 1
5.8 g (yield 87.3%) was obtained. (II)

[0064]

[Chemical 12]

In a 200 ml three-necked flask, 3.0 g (0.017 mol) of the p-nitrobenzhydrazide (b) and 3.1 g (0.10 mol) of the p-nitrobenzoyl chloride (c) were added.
017 mol) was added and the atmosphere was replaced with argon. To this, 50 ml of pyridine was added, and the mixture was heated under reflux. After 15 hours, the pyridine was distilled off, the reaction product was precipitated in water and suction filtered. The product was washed with water and vacuum dried to obtain 2.8 g of a reaction product (d). This reaction product (d) was used in the next reaction without purification. (III)

[0066]

[Chemical 13]

4.8 g of the above reaction product (d) was placed in a 200 ml three-necked flask and purged with argon. To this was added 90 ml of phosphoryl chloride POCl ₃ at room temperature. 1
After heating under reflux for 2 hours, the mixture was carefully poured into ice water, and the deposited precipitate was suction filtered, washed with water, and then vacuum dried. The obtained solid was purified by column chromatography to obtain 2.1 g of the desired compound of the formula (1-1). The yield based on the compound of formula (b) was 39.4%. Melting point: 126.2 ° C. Elemental analysis Calculated value (%) C53.9 N17.9 H2.6 Measured value (%) C53.6 N17.6 H2.8 The infrared absorption spectrum of the product is shown in FIG. << Single Layer Type Photoreceptor for Digital Light Source >> Examples 1 to 2 X-type metal-free phthalocyanine (X
φ, Ip = 5.38 eV) or 5 parts by weight of oxotitanyl phthalocyanine (Tiφ, Ip = 5.32 eV),
Compound 30 of formula (1-1) obtained in Synthesis Example 1 which is an electron transfer agent
Parts by weight, and 50 parts by weight of N, N, N ', N'-tetrakis (p-methylphenyl) -3,3'-dimethylbenzidine (DB, Ip = 5.56 eV), which is a hole transferring material,
80 parts by weight of 100 parts by weight of the binder resin, polycarbonate.
A single layer type photosensitive layer coating liquid was prepared by mixing and dispersing with 0 part by weight of tetrahydrofuran in a ball mill for 50 hours. Then, this coating solution is applied to the surface of an aluminum tube by a dip coating method, dried with hot air at 100 ° C. for 60 minutes, and an electrophotographic photoreceptor having a single-layer type photosensitive layer for a digital light source with a film thickness of 15 to 20 μm Was produced. Comparative Examples 1-2 As Examples 1-2, except that 30 parts by weight of 3,5-dimethyl-3 ', 5'-di-t-butyl-4,4'-diphenoquinone (DQ) was used as an electron transfer agent. Similarly, an electrophotographic photoreceptor having a single-layer type photosensitive layer for a digital light source was produced. Comparative Example 3 An electrophotographic photosensitive member having a single-layer type photosensitive layer for a digital light source was prepared in the same manner as in Examples 1 and 2 except that the electron transfer agent was not added. << Layered Photoreceptor for Digital Light Source >> Example 3 2 parts by weight of X-type metal-free phthalocyanine which is a charge generating agent and 1 part by weight of polyvinyl butyral which is a binder resin were mixed with 120 parts by weight of dichloromethane in a ball mill. Dispersion was performed to prepare a coating liquid for the charge generation layer. Then, this coating solution was applied onto the surface of the aluminum tube by a dip coating method and dried with hot air at 100 ° C. for 60 minutes to form a charge generation layer having a film thickness of 0.5 μm.

Next, 80 parts by weight of the compound of the formula (1-1) obtained in Synthesis Example 1, which is an electron transferring material, and 100 parts by weight of a polycarbonate, which is a binder resin, were placed in a ball mill together with 800 parts by weight of benzene. And mixed and dispersed to prepare a coating solution for the charge transport layer. Then, this coating solution is applied onto the charge generation layer by a dip coating method and dried with hot air at 90 ° C. for 60 minutes to form a charge transport layer having a film thickness of 15 μm, and a laminated photosensitive layer for a digital light source is obtained. Was prepared. Comparative Example 4 In the same manner as in Example 3 except that 80 parts by weight of 3,5-dimethyl-3 ′, 5′-di-t-butyl-4,4′-diphenoquinone (DQ) was used as the electron transfer agent, An electrophotographic photosensitive member having a laminated photosensitive layer for a digital light source was produced.

The following photosensitivity test I was conducted on the electrophotographic photoreceptors of the above-mentioned respective examples and comparative examples to evaluate their sensitivity characteristics. Photosensitivity test I Using a drum sensitivity tester manufactured by GENTEC, an applied voltage was applied to the surface of each of the photoconductors of Examples and Comparative Examples to charge the surface to + 700V. Then, the surface of the photoreceptor is irradiated with monochromatic light having a wavelength of 780 nm (half-value width of 20 nm) and a light intensity of 16 μW / cm ² extracted from white light of a halogen lamp which is an exposure light source using a bandpass filter (light irradiation time 80 msec. .), And 330 msec. From the start of exposure. The surface potential at the elapsed time was measured as the post-exposure potential VL (V). The smaller the post-exposure potential VL (V), the higher the sensitivity of the electrophotographic photosensitive member. Table 1 shows the results.

[0070]

[Table 1]

<< Single Layer Type Photoreceptor for Analog Light Source >> Example 4 As a charge generating agent, 5 parts by weight of perylene pigment (Pe) in which R ^{a and} R ^b in the general formula (3) are both methyl groups was used. An electrophotographic photoreceptor having a single-layer type photosensitive layer for an analog light source was produced in the same manner as in Examples 1 and 2 except the above. Comparative Example 5 3,5-Dimethyl-3 ′, 5′-di-t as an electron transfer agent
An electrophotographic photoreceptor having a single-layer type photosensitive layer for an analog light source was produced in the same manner as in Example 4 except that 30 parts by weight of -butyl-4,4'-diphenoquinone (DQ) was used. Comparative Example 6 An electrophotographic photoreceptor having a single-layer type photosensitive layer for an analog light source was produced in the same manner as in Example 4 except that the electron transfer agent was not blended. << Layered Photoreceptor for Analog Light Source >> Example 5 The same procedure was performed except that 2 parts by weight of perylene pigment (Pe) in which R ^{a and} R ^b in the general formula (3) were both methyl groups was used as the charge generating agent. In the same manner as in Example 3, an electrophotographic photosensitive member having a laminated photosensitive layer for analog light source was produced. Comparative Example 7 In the same manner as in Example 5 except that 80 parts by weight of 3,5-dimethyl-3 ′, 5′-di-t-butyl-4,4′-diphenoquinone (DQ) was used as the electron transport agent. An electrophotographic photoreceptor having a laminated photosensitive layer for an analog light source was produced.

For the electrophotographic photoreceptors of the above-mentioned respective examples and comparative examples
Then, perform the following photosensitivity test II and evaluate its sensitivity characteristics.
did. Photosensitivity test II Drum sensitivity tester manufactured by GENTEC
Voltage applied to the surface of the photoconductor of each of the examples and comparative examples.
Was added to charge the surface to + 700V. Just
Then, the white light of the halogen lamp (light intensity 1
47 lμW / cm ²) On the surface of the photoconductor (irradiation time
50 msec. ), And 330 msec. From the start of exposure.
The surface potential at the time when it has passed is the post-exposure potential VL (V).
And measured. The smaller the post-exposure potential VL (V), the more
The child photoconductor has high sensitivity. The results are shown in Table 2.

[0073]

[Table 2]

From Table 1 and Table 2, the photoreceptors of Examples are
It can be seen that the residual potential is low and the sensitivity is high. Synthesis Example 2 (Synthesis of Exemplified Compound (1-6) Above) (I)

[0075]

Embedded image

30.0 g (0.17 mol) of pt-butylbenzoic acid (e), 100 ml of ethanol and 4 ml of sulfuric acid were added to a 300 ml eggplant-shaped flask, and the mixture was heated under reflux. After 6 hours, the mixture was cooled, ethanol was distilled off, water was added, and the mixture was extracted with ether three times. The organic layer was washed with water, dried over anhydrous sodium sulfate, filtered, and the solvent was evaporated. The obtained liquid is purified by column chromatography and p
Ethyl -t-butylbenzoate (f) was obtained. (II)

[0077]

[Chemical 15]

The 200 ml two-necked flask was replaced with argon, 20 ml of hydrazine monohydrate was added, and the mixture was heated to reflux. 20 g (0.1 mol) of the ethyl p-t-butylbenzoate (f) obtained in (I) above was slowly added dropwise to this, and the mixture was heated under reflux as it was. After 15 hours, the mixture was cooled, the obtained white crystals were filtered, the filtrate was concentrated, the obtained solid and the white crystals were combined, and recrystallized from ether to give pt-butylbenzhydrazide (g). 16.7 g (yield 87.2
%) Was obtained. (III)

[0079]

Embedded image

The inside of a 200 ml three-necked flask was replaced with argon, and the above-mentioned pt-butylbenzhydrazide was added thereto.
3.1 g (0.016 mol) of (g) and 3.0 g (0.016 mol) of p-nitrobenzoyl chloride were put, dissolved in 50 ml of pyridine, and heated under reflux. After 13 hours, the pyridine was distilled off, the reaction product was precipitated in water and suction filtered. This product was washed with water and vacuum dried to obtain 5.2 g of a reaction product (h). This reaction product (h) was used in the next reaction without purification. (IV)

[0081]

[Chemical 17]

After purging the inside of a 200 ml three-necked flask with argon, 4.8 g of the above reaction product (h) was added, and 100 ml of phosphoryl chloride POCl ₃ was added thereto at room temperature.
After heating under reflux for 13 hours, the mixture was carefully poured into ice water, and the deposited precipitate was suction filtered, washed with water, and then vacuum dried. The white solid obtained is purified by column chromatography,
2.8 g of the desired compound of formula (1-6) was obtained. Formula (g)
The yield based on the compound of 54.2% was 54.2%. Melting point: 119.3 ° C. Elemental analysis Calculated value (%) C66.9 N13.0 H5.26 Measured value (%) C67.1 N13.2 H6.24 The infrared absorption spectrum of the product is shown in FIG. Synthesis Example 3 (Synthesis of Exemplified Compound (1-8) Above) (I)

[0083]

Embedded image

The inside of a 200 ml three-necked flask was replaced with argon, and 3.07 g (0.016 mol) of pt-butylbenzhydrazide (g) obtained in (II) of Synthesis Example 2 was added thereto. 3.7 g (0.016) of 5-dinitrobenzoyl chloride
Mol) and dissolved in 50 ml of pyridine and heated to reflux. Thereafter, in the same manner as in (III) of Synthesis Example 2, 6.3 g of a reaction product (i) was obtained. This reaction product (i) was used in the next reaction without purification. (II)

[0085]

[Chemical 19]

After replacing the inside of a 200 ml three-necked flask with argon, 6.0 g of the above reaction product (i) was added, and 80 ml of phosphoryl chloride POCl ₃ was added thereto at room temperature to give 13
Heated to reflux for hours. Thereafter, in the same manner as in (IV) of Synthesis Example 2, 3.1 g (yield 51.3%) of a reaction product (1-8) was obtained. Melting point: 123.3 ° C. Elemental analysis Calculated value (%) C58.7 N15.2 H4.35 Measured value (%) C58.6 N15.1 H4.35 The infrared absorption spectrum of the product is shown in FIG. Synthesis Example 4 (Synthesis of Exemplified Compound (1-9) Above) (I)

[0087]

Embedded image

3-Nitro-in a 300 ml eggplant flask.
25 g (0.14 mol) of 4-methylbenzoic acid (j), 100 ml of ethanol and 5 ml of sulfuric acid were added, and the mixture was heated under reflux. After 5 hours, the mixture was cooled, ethanol was distilled off, water was added, and chloroform extraction was performed 3 times. Wash the organic layer with water,
After drying over anhydrous sodium sulfate, it was filtered and chloroform was distilled off. The obtained solid was purified by column chromatography, ethyl 3-nitro-4-methylbenzoate
24.9 g (85.0%) of (k) was obtained. (II)

[0089]

[Chemical 21]

A 200 ml two-necked flask was purged with argon, charged with 20 g (0.1 mol) of ethyl 3-nitro-4-methylbenzoate (k) obtained in the above (I) and 50 ml of dry ethanol, and heated. Refluxed. Hydrazine-
12 ml of the hydrate was slowly added dropwise using a dropping funnel, and the mixture was heated under reflux for 13 hours. Then, hydrazine-hydrate and ethanol were distilled off, the obtained solid was put into ethanol, stirred, and the solid was filtered and then dried,
White crystalline 3-nitro-4-methylbenzhydrazide
(1) 14.3 g (yield 73%) was obtained. (III)

[0091]

[Chemical formula 22]

The inside of a 200 ml three-necked flask was replaced with argon, and 3.5 g (0.018 mol) of the above-mentioned 3-nitro-4-methylbenzhydrazide (l) and 3.3 g of p-nitrobenzoyl chloride ( 0.018 mol),
It was dissolved in 50 ml of pyridine and heated under reflux for 14 hours.
After cooling, pyridine was distilled off, the reaction product was poured into water to cause precipitation, and suction filtration was performed. This product was washed with water, filtered, and dried under vacuum to obtain 5.6 g of a reaction product (m). This reaction product (m) was used in the next reaction without purification. (IV)

[0093]

[Chemical formula 23]

After purging the inside of a 200 ml two-necked flask with argon, 5.6 g of the above reaction product (m) was added, and 90 ml of phosphoryl chloride POCl ₃ was added thereto at room temperature to give 1
The mixture was heated under reflux for 3 hours. Thereafter, 2.7 g of the target compound of the formula (1-9) was obtained in the same manner as in IV of Synthesis Example 2. formula
The yield based on the compound (l) was 44.6%. Melting point: 122.7 ° C. Elemental analysis Calculated value (%) C55.2 N17.2 H3.1 Measured value (%) C55.1 N17.5 H3.3 The infrared absorption spectrum of the product is shown in FIG. Synthesis Example 5 (Synthesis of Exemplified Compound (1-10) Above) (I)

[0095]

[Chemical formula 24]

The inside of a 200 ml three-necked flask was replaced with argon, and this was replaced with 3-nitro-4- obtained in (II) of Synthesis Example 4.
3.5 g (0.018 mol) of methylbenzhydrazide (l) and 4.4 g of benzoyl 3,5-dinitrochloride (0.
018 mol) and dissolved in 60 ml of pyridine,
The mixture was heated under reflux for 14 hours. Thereafter, in the same manner as in (III) of Synthesis Example 4, 5.7 g of a reaction product (o) was obtained. This reaction product (o) was used in the next reaction without purification. (II)

[0097]

[Chemical 25]

After purging the inside of a 300 ml two-necked flask with argon, 5.5 g of the above reaction product (o) was added, and 50 ml of phosphoryl chloride POCl ₃ was added thereto at room temperature to give 1
The mixture was heated under reflux for 6 hours. Then, 3.1 g of the target compound of the formula (1-10) was obtained in the same manner as in IV of Synthesis Example 2. formula
The yield based on the compound of (l) was 52.5%. Melting point: 124.4 ° C. Elemental analysis Calculated value (%) C48.5 N18.9 H2.4 Measured value (%) C48.3 N18.8 H2.6 << Single layer type photoreceptor for digital light source >> Examples 6 to 13 Other than using any of the oxadiazole derivatives (1-6), (1-8), (1-9) and (1-10) obtained in Synthesis Examples 2 to 5 as an electron transfer agent A single-layer type electrophotographic photosensitive member was produced in the same manner as in Examples 1 and 2. << Layered Photoreceptor for Digital Light Source >> Examples 14 to 17 Oxadiazole derivatives (1-6), (1-8), (1-9) and (1) obtained in Synthesis Examples 2 to 5 as electron transfer agents. A single-layer type electrophotographic photosensitive member was produced in the same manner as in Example 3 except that any one of (-10) was used.

The above-mentioned photosensitivity test I was conducted on each of the photoconductors obtained in Examples 6 to 17 to evaluate their sensitivity characteristics.
Table 3 shows the results.

[0100]

[Table 3]

<< Single-Layer Photoreceptor for Analog Light Source >> Examples 18 to 21 Oxadiazole derivatives (1-6), (1-8), (1-9 as electron transfer agents obtained in Synthesis Examples 2 to 5) ) And (1-10) were used, and a single-layer type electrophotographic photoreceptor was prepared in the same manner as in Example 4. << Layered Photoreceptor for Digital Light Source >> Examples 22 to 25 Oxadiazole derivatives (1-6), (1-8), (1-9) and (1) obtained in Synthesis Examples 2 to 5 as electron transport agents A laminated electrophotographic photosensitive member was produced in the same manner as in Example 5 except that any one of (-10) was used.

The photosensitivity test II described above was conducted on each of the photoconductors obtained in Examples 18 to 25 to evaluate their sensitivity characteristics. The results are shown in Table 4.

[0103]

[Table 4]

From Tables 3 and 4, it can be seen that the photoconductors of the respective examples have low residual potential and high sensitivity. Examples 26-41 and Comparative Examples 8-15 5 parts by weight of an X-type metal-free phthalocyanine pigment as a charge generating agent, and N, N, N ', N'-tetrakis (p-methylphenyl) -3 as a hole transferring material. , 3'-Dimethylbenzidine (50 parts by weight) and Synthesis Example 1 as an electron transfer agent
Oxadiazole derivative (1-1), (1-6), (1-
8) and 30 parts by weight of (1-9), 10 parts by weight of any of the following compounds a to e as an electron accepting compound, and 100 parts by weight of polycarbonate as a binder resin,
800 parts by weight of dichloromethane as a solvent was mixed and dispersed in a ball mill for 50 hours to prepare a single-layer type photosensitive layer coating solution. Next, this coating solution is applied onto an aluminum tube and then dried with hot air at 100 ° C. for 60 minutes to give a film thickness of 15-2.
A 0 μm single-layer type electrophotographic photosensitive member was produced. Electron-accepting compound a: p-benzoquinone (oxidation-reduction potential: -0.81 V) b: 2,6-di-t-butyl-p-benzoquinone (oxidation-reduction potential: -1.30 V) c: 3,5-dimethyl -3 ', 5'-di-t-butyl-
4,4'-diphenoquinone (redox potential: -0.86
V) d: 3,3 ', 5,5'-tetra-t-butyl-4,4'
-Diphenoquinone (oxidation-reduction potential: -0.94V) e: 2,5-dichloro-p-benzoquinone (oxidation-reduction potential: -0.51V) Using each of the obtained electrophotographic photoreceptors, the above-mentioned photosensitivity test Then, the sensitivity characteristic was evaluated.

The results are shown in Table 5.

[0106]

[Table 5]

[0107]

The oxadiazole derivative of the present invention has a high electron transporting ability. Therefore, the electrophotographic photosensitive member of the present invention containing the oxadiazole derivative as an electron transporting agent has an effect that the residual potential is remarkably lowered, and that it has high sensitivity to charging. Therefore, when the photoconductor of the present invention is used, the speed of a copying machine, a printer or the like can be increased.

Further, by adding an electron-accepting compound having a specific oxidation electric potential, the residual potential is further lowered and a photosensitive member having improved sensitivity can be obtained.

[Brief description of drawings]

FIG. 1 is a graph showing a relationship between a traction voltage (V) and a current (A) for obtaining a redox potential in the present invention.

FIG. 2 is an infrared absorption spectrum of the product obtained in Synthesis Example 1.

FIG. 3 is an infrared absorption spectrum of the product obtained in Synthesis Example 2.

FIG. 4 is an infrared absorption spectrum of the product obtained in Synthesis Example 3.

5 is an infrared absorption spectrum of the product obtained in Synthesis Example 4. FIG.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] February 21, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

The charge-generating agent that absorbs light upon exposure to the photosensitive member produces ion pairs [holes (+) and electrons (-)]. In order for the generated ion pairs to become free carriers and effectively cancel the surface charge, it is preferable that the ion pair recombine and disappear. Here, in the presence of an electron-accepting compound having an oxidation-reduction potential of −0.8 to −1.3 V, LUMO ( of an electron-free molecular orbital)
It is the orbit with the lowest energy level and is excited
The electrons usually move in this orbit. Since the energy level of ) is lower than that of the charge generating agent, when the ion pair is generated, the electron moves to the electron accepting compound and the ion pair is easily separated into the carrier. That is, the electron-accepting compound acts on the charge generation to improve the generation efficiency.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hirofumi Kawaguchi 1-2-2 Tamatsukuri, Chuo-ku, Osaka City, Osaka Prefecture Mita Kogyo Co., Ltd. (72) Yasushi Mizuta 1-2-chome Tamatsukuri, Chuo-ku, Osaka City, Osaka Prefecture No. 28 Inside Mita Industry Co., Ltd.

Claims (5)

[Claims] 1. Formula (1): (In the formula, R ¹ and R ² are the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and n, m, p and q are the same or different, and are 0 to 2
Is an integer. However, n and m must not be 0 at the same time. ) An oxadiazole derivative represented by: 2. The n and m are the same or different and 1
Alternatively, the oxadiazole derivative according to claim 1, which is an integer of 2. 3. The oxadiazole derivative according to claim 1, which has an asymmetric structure. 4. An electrophotographic photosensitive member having an organic photosensitive layer provided on a conductive substrate, wherein the organic photosensitive layer contains an oxadiazole derivative represented by the following general formula (1) as an electron transfer agent. An electrophotographic photoreceptor characterized by: Embedded image (In the formula, R ¹ and R ² are the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and n, m, p and q are the same or different, and are 0 to 2
Is an integer. However, n and m must not be 0 at the same time. ) 5. The organic photosensitive layer is -0.8 to -1.3V.
The electrophotographic photosensitive member according to claim 4, which contains the electron-accepting compound having the redox potential of.