JPH06130688A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body having high sensitivity and excellent in repetitive characteristics and residual potential characteristics. CONSTITUTION:A photosensitive layer contg. a diphenoquinone compd. represented by formula I as an electron transferring material and a compd. represented by formula II as a positive hole transferring material is formed on an electric conductive substrate. In the formula I, each of R1-R4 is H, alkyl which may have a substituent, alkoxy or aryl but two of R1-R4 are the same group. In the formula II, each of R5-R10 is alkyl, alkoxy, halogen, aryl, nitro, cyano or alkylamino, each of (p) and (q) is an integer of 0-1 and each of (k), (l), (m) and (o) is an integer of 0-5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member used in an image forming apparatus using an electrophotographic method such as an electrostatic copying machine and a laser beam printer.

[0002]

2. Description of the Related Art The electrophotographic method such as the Carlson process is a step of uniformly charging the surface of an electrophotographic photosensitive member by corona discharge, and exposing the charged surface of the electrophotographic photosensitive member to an electrostatic latent image on the surface. An exposure step of forming an image, a developing step of bringing a developer into contact with the formed electrostatic latent image, and developing the electrostatic latent image into a toner image by toner contained in the developer, and a toner image Transfer step of transferring the toner to paper, a fixing step of fixing the transferred toner image, and a transfer step,
And a cleaning step for removing the toner remaining on the photoconductor.

As the electrophotographic photosensitive member used in the electrophotographic method, there are an inorganic photosensitive member using a photosensitive layer containing an inorganic material such as selenium and an organic photosensitive member using a photosensitive layer containing an organic material. is there. Organic photoreceptors are cheaper and more pollution-free than inorganic photoreceptors, and because of their diverse molecular structures, they have many advantages such as a high degree of freedom in functional design and high productivity. In recent years, extensive research has been advanced.

In such an organic photoreceptor, generally, a function-separated type photosensitive layer containing a charge generating material for generating charges by light irradiation and a charge transporting material for transporting the generated charges is often used. . In order to satisfy various conditions desired for such an organic photoreceptor, it is necessary to appropriately select materials to be combined such as a charge generating material and a charge transporting material.

As the charge transporting material, various kinds of substances have been studied in the past, and many substances such as polyvinylcarbazole, oxadiazole type compounds, pyrazoline type compounds and hydrazone type compounds have been proposed. Since these charge-transporting materials are hole-transporting materials, the charge-generating layer and the charge-transporting layer are formed on a conductive substrate, which is one of the function-separated type photoreceptors that are currently the mainstream of organic photoreceptors. A negative charging process is inevitably required for a laminated type photoreceptor of a system in which layers are sequentially laminated.

However, the negatively charged organic photoreceptor may pollute the environment due to generation of ozone or may be deteriorated due to oxidation of the photoreceptor. To prevent this, a system that does not generate ozone, There is a disadvantage that a system for discarding ozone in the image forming apparatus is required, which complicates the process and system. Use of an electron transporting material as a charge transporting material has been studied in order to solve these drawbacks, and an electrophotographic photosensitive member using a compound having a diphenoquinone skeleton as the electron transporting material, which can be used in positive charging, is provided. Proposed (Japanese Patent Laid-Open No. 1-20
No. 6349).

The compound having a diphenoquinone skeleton is an electron acceptor having a delocalized π electron system,
Electrons can be transported by an electron transfer reaction involving an anion radical state. By the way, if a photoconductor having both positive charging property and negative charging property can be used, the application range of the photoconductor can be further expanded. As such a photoreceptor, by containing an electron transporting material having a diphenoquinone structure as a charge transporting material and a polysilane-based hole transporting material in the photosensitive layer, it can be used in both positive and negative charging, and has high sensitivity and repetitive characteristics. It is also considered to obtain an excellent photoconductor.

[0008]

The diphenoquinone derivative is said to exhibit good transportability, but it has poor sensitivity for use in high-speed copying machines and is not yet sufficiently satisfactory in practical use. . The present inventors have found that among various diphenoquinone derivatives, a diphenoquinone derivative containing a substituent in a specific positional relationship is remarkably excellent in sensitivity as compared with a diphenoquinone derivative conventionally known as an electron transfer agent. Found.

Further, in order to manufacture an organic photoconductor using various materials, it is necessary to select materials having good matching so as to satisfy electrophotographic characteristics. For example, even if charge transporting materials having high charge transporting ability are combined, good electrophotographic characteristics are not always obtained, and in a system in which a hole transporting material and an electron transporting material coexist as charge transporting materials, Attention should be paid to the formation of the transfer complex. That is, when the charge transfer complex is formed, recombination occurs between the holes and the electrons, and the transfer of charges is reduced as a whole. Furthermore, when the energy gap between the HOMO of the hole transport material and the LUMO of the electron transport material coincides with the wavelength energy of the main exposure and the neutralization light with which the photoreceptor is irradiated, absorption of light by the charge transfer complex occurs, and the charge is transferred. This will lead to a drastic decrease in generation efficiency.

It is inferred that the formation of the charge transfer complex has a causal relationship with the way in which the electron clouds of the hole transport material and the electron transport material overlap. The present invention is intended to solve the above problems, and an object thereof is to provide an electrophotographic photoreceptor having high sensitivity and excellent repetitive characteristics and residual potential characteristics.

[0011]

Means and Actions for Solving the Problems On the conductive substrate, the following general formula (1) as an electron transport material:

[0012]

[Chemical 3]

(Wherein R1, R2, R3 and R4 are
A hydrogen atom, an alkyl group which may have a substituent, an alkoxy group and an aryl group are shown. However, two of R1, R2, R3 and R4 are the same group. ) And the following general formula (2) as a hole transport material:

[0014]

[Chemical 4]

(In the formula, R5, R6, R7, R8, R9 and R10 each independently represent an alkyl group, an alkoxy group, a halogen atom, an aryl group, a nitro group, a cyano group or an alkylamino group. q represents an integer of 0 to 4. k, l, m, and o represent integers of 0 to 5.)
The inventors have found that a photosensitive layer containing a compound represented by the following should be provided, and completed the present invention.

According to the present invention, the diphenoquinone derivative having the structure represented by the above general formula (1) has remarkably improved sensitivity and sensitivity while maintaining substantially the same chargeability and repetitive characteristics as those of the diphenoquinone derivative known as an electron transfer agent. This is based on the finding that the residual potential is shown. Conventionally, as a diphenoquinone derivative that is easily dissolved in a solvent and therefore has good compatibility with a binder resin, and has the best electron transport performance,
^{3-dimethyl-3, 5,} - di tert ^butyl-4,4,
-Diphenoquinone (DMDB), that is, the following formula (a)

[0017]

[Chemical 5]

Derivatives of are known. This DMDB
Among the diphenoquinone derivatives, although they have high charging characteristics and excellent sensitivity, further improvement in sensitivity is required for use in high-speed copying machines, etc., and they are still sufficiently satisfactory in practical use. You don't get it. On the other hand, when the diphenoquinone derivative having the structure represented by the general formula (1) is used according to the present invention, the sensitivity and the residual potential are remarkably improved while maintaining the charging characteristics and the repeating characteristics at the same level as DMDB. It becomes possible (see the example described later).

The fact that the diphenoquinone derivative used in the present invention shows the above-mentioned improvement has been found as a phenomenon as a result of many experiments, but since this derivative has a lower symmetry, it has a problem in the photosensitive layer. It is presumed that formation of aggregates or aggregates is unlikely to occur, and therefore diphenoquinone molecules are effectively distributed in the same volume, which is advantageous for carrying out hopping conduction of electrons.

Therefore, the inventors of the present invention selected a specific hole-transporting material for the diphenoquinone-based compound to obtain electrophotographic characteristics satisfying high performance, and the hole-transporting material to be used. Various studies were conducted. Matching by selecting the compound represented by the general formula (1) as the specific electron transport material of the present invention and the compound represented by the general formula (2) as the specific hole transport material Although the action of is not clear, from the comparison of the examples and comparative examples described later, as a result, sensitivity, repeatability,
It is understood that this leads to improvement in residual potential characteristics.

That is, even if the output of the exposure lamp that is standardly installed in the copying machine is not increased, problems such as fog do not occur, which leads to a longer life of the exposure lamp and a reduction in power consumption. It is estimated to be.

[0022]

[Preferable Embodiment] As the charge generating material , conventionally known materials can be used, and examples thereof include selenium, selenium-tellurium, selenium-arsenic, amorphous silicon, pyrylium salts, azo pigments, perylene pigments, Ansanthuron-based pigments, phthalocyanine-based pigments, indigo-based pigments, triphenylmethane-based pigments, slene-based pigments, toluidine-based pigments, pyrazoline-based pigments, quinacridone-based pigments, pyrrolopyrrole-based pigments, and the like, preferably metal-free phthalocyanine ,
Copper phthalocyanine, oxotitanyl phthalocyanine and the like are mentioned, and particularly, a material showing an ionization potential of 5.3 eV to 5.6 eV [the measurement by an atmospheric photoelectron spectrometer (AC-1 by Riken Keiki Co., Ltd.)] is preferable. There are the following, as particularly preferable ones. X-type metal-free phthalocyanine (IP = 5.38e
V) β-type metal-free phthalocyanine (IP = 5.32e
V) Oxotitanyl phthalocyanine (IP = 5.32 eV) 1,4-dithioketo-3,6-diphenyl-pyrrolo-
(3, 4-C) pyrrole (IP = 5.46 eV) N, N-bis ^{(3, 5,} - dimethylphenyl) perylene-3,4,9,10-tetracarboxylic diimide (I
P = 5.60 eV) Charge Transport Material The electron transport material represented by the general formula (1) and the hole transport material represented by the general formula (2) are used.

In the diphenoquinone compound represented by the general formula (1), examples of the alkyl group corresponding to R1, R2, R3 and R4 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group and an isobutyl group. Group, t-butyl group, pentyl group, hexyl group and the like. As the alkoxy group, for example, a methoxy group,
Examples thereof include an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a t-butoxy group and a hexyloxy group.

As the aryl group, for example, a phenyl group,
Examples thereof include a tolyl group, a xylyl group, a biphenyl group, a naphthyl group, an anthryl group and a phenanthryl group. Examples of the substituent substituting the above groups include a methyl group, an ethyl group, an isopropyl group, a propyl group, a butyl group, an isobutyl group,
t-butyl group, pentyl group, methoxy group, ethoxy group,
Examples include propoxy group, isopropoxy group, butoxy group, isobutoxy group, t-butoxy group and the like.

As the diphenoquinone derivative represented by the general formula (1), those represented by the following formulas (3), (4) and (5) are used.

[0026]

[Chemical 6]

(In the formula, R1 ^, R2 ^, R3 ^, are hydrogen atoms, optionally substituted alkyl groups, alkoxy groups,
Indicates an aryl group. ) The general formulas (3), (4),
(5) Specific examples of the diphenoquinone derivative represented by the, R1 in each ^formula, to ^R3, a compound having a group such as shown in Table 1 is exemplified as a group.

[0028]

[Table 1]

The diphenoquinone derivative represented by the above general formula (3), (4) or (5) may be used alone,
Alternatively, they may be mixed and used. Further, the diphenoquinone derivative represented by the above general formula (3), (4) or (5) can be synthesized by various conventionally known methods. For example, the diphenoquinone derivative is represented by the above general formula (3). The diphenoquinone derivative is represented by the following formula (i)

[0030]

[Chemical 7]

[0031] (wherein ^R1, the formula (3) similar to)
A disubstituted phenol represented by the following formula and the following formula (ii)

[0032]

[Chemical 8]

[0033] (wherein ^{R2,, R3,} is the general formula (3) similar to) the copper salt in a polar solvent to a disubstituted phenol represented by - and molecular oxygen in the presence of a tertiary amine complex catalyst Synthesized by contacting. Further, the diphenoquinone derivative represented by the general formula (4) has the following formulas (iii) (iv) instead of the formulas (i) (ii).
It is synthesized in the same manner as described above except that the disubstituted phenol represented by

[0034]

[Chemical 9]

[0035] (wherein ^{R1,, R2,, R3,} is the general formula (4) similar to) Further, diphenoquinone derivative represented by the above general formula (5) is replaced by the formula (i) (ii) Then, the following formula (v)
It is synthesized in the same manner as described above except that the disubstituted phenol represented by (vi) is used.

[0036]

[Chemical 10]

[0037] (wherein ^{R1,, R2,, R3,} is the general formula (5) described above) in the hole transporting material represented by the general formula (2), R5 in the formula, R6, R7, R8 Examples of the alkyl group, alkoxy group and aryl group corresponding to R 9, R 9 and R 10 include the same as those in the above general formula (1). Examples of the halogen atom include chlorine, iodine, bromine and fluorine.

Examples of the alkylamino group include methylamino group, dimethylamino group, ethylamino group, diethylamino group, propylamino group, isopropylamino group, butylamino group, isobutylamino group, t-butylamino group, pentylamino group. , Hexylamino group and the like. Specific compounds of the compound represented by the general formula (2) include, for example, No. 2 in Table 2. Examples include those shown in A1 to A15. In the table, for example, "3-CH
₃ "that indicates that the methyl group is bonded to the 3-position of the phenyl group," 3, 5-CH ₃ "is the methyl group at the 3-position and 5-position of the phenyl group are bonded respectively Shows.

[0039]

[Table 2]

The compound (2) can be synthesized by various methods. For example, the compound represented by the following general formula (6) and the compounds represented by the general formulas (7) to (10). It can be synthesized by reacting with and simultaneously.

[0041]

[Chemical 11]

(In the formula, R5, R6, R7, R8, R9 and R10 each independently represent an alkyl group, an alkoxy group, a halogen atom, an aryl group, a nitro group, a cyano group or an alkylamino group. P, q represents an integer of 0 to 4. k, l, m and o represent an integer of 0 to 5. X
Represents a halogen atom. ) The reaction between the compound represented by the general formula (6) and the compounds represented by the general formulas (7) to (10) is usually carried out in an organic solvent, and as a solvent, this reaction does not adversely affect. Any solvent can be used as long as it is a solvent, for example, nitrobenzene, dichlorobenzene,
Examples include organic solvents such as quinoline, N, N-dimethylformamide, N-methylpyrrolidone and dimethyl sulfoxide. The reaction is usually carried out at a temperature of 150 to 250 ° C. in the presence of a catalyst such as copper powder, copper oxide and copper halide, and a basic substance such as sodium hydroxide and potassium hydrogen carbonate.

After completion of the reaction, the reaction mixture can be concentrated and easily separated and purified by a conventional means such as recrystallization, solvent extraction, column chromatography and the like. The compounds represented by the above general formulas (1) and (2), which are charge transport materials, can be used in combination with other conventionally known charge transport materials. As the conventionally known charge transport material, various electron-withdrawing compounds and electron-donating compounds can be used.

Examples of the electron-withdrawing compound include 2,
^{6-dimethyl-2,, 6,} - di tert- dibutyl phenoxide diphenoquinone derivatives non like, malononitrile, thiopyran compounds, tetracyanoethylene, 2,
4,8-trinitrothioxanthone, 3,4,5,7-
Tetranitro-9-fluorenone, dinitrobenzene,
Examples include dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride, and dibromomaleic anhydride.

As the electron donating compound, 2,5
-Oxadiazole compounds such as di (4-methylaminophenyl) and 1,3,4-oxadiazole, 9- (4
-Styryl compounds such as diethylaminostyryl) anthracene, carbazole compounds such as polyvinylcarbazole, pyrazoline compounds such as 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline, hydrazone compounds, triphenylamine compounds, indole Compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds,
Examples thereof include nitrogen-containing cyclic compounds such as imidazole compounds, pyrazole compounds, and triazole compounds, and condensed polycyclic compounds.

These charge transport materials may be used alone or in combination of two or more. When a charge transporting material having film-forming property such as polyvinylcarbazole is used,
The binder resin is not always necessary. Binder Resin Various resins can be used as the binder resin. For example, styrene-based polymer, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic copolymer, styrene-acrylic acid copolymer, polyethylene, ethylene-vinyl acetate copolymer , Chlorinated polyethylene, polyvinyl chloride, polypropylene, vinyl chloride-vinyl acetate copolymer, polyester alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin, Thermoplastic resin such as polyester resin, silicone resin, epoxy resin,
Examples thereof include phenol resins, 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. As the conductive substrate on which the conductive substrate photosensitive layer is formed, various materials having conductivity can be used, for example, aluminum, 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. Additives The organic photosensitive layer may contain additives such as a sensitizer, a fluorene compound, an antioxidant, a deterioration inhibitor such as an ultraviolet absorber, and a plasticizer.

Suitable antioxidants are, for example:

[0049]

[Chemical 12]

[0050]

[Chemical 13]

When the sterically hindered phenolic antioxidant is blended in an amount of 0.1 to 50% by weight based on the total solid content,
It was found that the durability of the photosensitive layer can be significantly improved without adversely affecting the electrophotographic characteristics. In order to improve the sensitivity of the charge generation layer, for example, terphenyl,
Known sensitizers such as halonaphthoquinones and acenaphthylene may be used in combination with the charge generating material. Structure of Photoreceptor The photoconductor of the present invention can be applied to either a single layer type or a laminated type as a photosensitive layer. However, the effect of the combination of the electron transporting material and the hole transporting material becomes more remarkable particularly in the single-layer type photosensitive layer in which both materials are contained in the same layer. It can be said that it is more preferable to apply it to an electrophotographic photoreceptor having a photosensitive layer.

In order to obtain a single-layer type photoreceptor, a charge generating material, a compound represented by the general formula (1) which is an electron transport material, and a general formula (2) which is a hole transport material are used. A photosensitive layer containing the compound shown and a binder resin may be formed on the conductive substrate by means of coating or the like. That is, the principle of charge image generation in the above-mentioned single layer system is that, when charges (holes / electrons) are generated in the charge generation material by exposure, electrons are injected into the electron transport material and holes are injected into the hole transport material. The respective charges (holes / electrons) injected thereafter are transferred in the respective transport materials without being trapped on the way, and finally transported to the surface of the photosensitive layer or the surface of the conductive substrate. It is a thing.

That is, in the above single-layer type photoconductor,
Not only can the trapping of charges be suppressed and the sensitivity can be improved, but it can also be used as a dual charging photoconductor and has a wide range of applications. Further, since the single-layer type photoreceptor does not need to be coated twice on the photosensitive layer due to its constitution, the productivity is improved. Further, in order to obtain a laminated type photoreceptor, a charge generating layer containing a charge generating material is formed on a conductive substrate by means such as vapor deposition or coating, and the electron transporting material is formed on the charge generating layer. A charge transporting layer containing a compound represented by the general formula (1), a compound represented by the general formula (2), which is a hole transporting material, and a binder resin may be formed. Alternatively, conversely to the above, the charge transport layer may be formed on the conductive substrate, and then the charge generation layer may be formed.

The above-mentioned laminated type photoconductor can be used as a dual charging photoconductor and has a wide range of applications. In addition, a hole transport layer containing a compound represented by the general formula (2), which is a hole transport material, and a binder resin is formed on a conductive substrate, and vapor deposition is performed on the hole transport layer. Alternatively, a charge generation layer containing a charge generation material is formed by a means such as coating, and the general formula (1), which is an electron transport material, is formed on the charge generation layer.
An electron transport layer containing a compound represented by and a binder resin may be formed.

The above-mentioned laminated type photoreceptor is a positive charging type. Alternatively, conversely to the above, the electron transport layer may be formed on the conductive substrate, and then the charge generation layer and the hole transport layer may be sequentially laminated. The laminated type photoreceptor of the above type is a negative charging type. Furthermore, a protective layer may be provided on the organic photosensitive layer, or an intermediate layer may be provided between the organic photosensitive layer and the conductive substrate.

When the organic photosensitive layer is formed as a single layer, the film thickness of the organic photosensitive layer is preferably 10 to 50 μm, more preferably 15 to 30 μm. The content of the charge generating material is preferably in the range of 1 to 20 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the binder resin of the organic photosensitive layer. When the content of the charge generating material is less than 1 part by weight, the resulting photoreceptor has a low charge generating ability. On the contrary, the content of the charge generation material is 2
If the amount exceeds 0 part by weight, the abrasion resistance of the obtained photoreceptor may be reduced.

[0057] The content of the electron transporting material represented by the above general formula (1) it is preferably is contained in a range of 10 to 100 by weight parts of the binder resin 100 parts by weight of an organic photosensitive layer , more preferably from 20 to 70 by weight part. If the content of the electron transporting material is less than 10 parts by weight, the sensitivity and repeatability of the resulting photoreceptor will be poor. On the other hand, if the content of the electron transport material exceeds 100 parts by weight, the abrasion resistance of the obtained photoreceptor may be reduced.

The content of the hole transport material represented by the general formula (2) is preferably 10 to 100 parts by weight based on 100 parts by weight of the binder resin of the organic photosensitive layer. And more preferably 20 to 70 parts by weight. When the content of the hole transport material is less than 10 parts by weight, the sensitivity of the resulting photoreceptor becomes poor. On the other hand, if the content of the hole transport material exceeds 100 parts by weight, the abrasion resistance of the resulting photoreceptor may be reduced.

The content of the electron transport material represented by the general formula (1) is 20 to 80% by weight in the charge transport material.
It is contained, particularly preferably 30 to 70% by weight. When the content of the electron transporting material in the charge transporting material is less than 20% by weight, the sensitivity of the obtained photoreceptor,
Repeatability deteriorates. On the contrary, when the content of the electron transporting material exceeds 80% by weight, the sensitivity of the obtained photoreceptor becomes poor.

When the organic photosensitive layer is composed of a charge generation layer and a charge transport layer, the thickness of the charge generation layer is 0.1.
To 5 μm is preferable, and more preferably 0.5 to 2 μm.
Is. The thickness of the charge transport layer is preferably 10 to 50 μm, more preferably 15 to 30 μm. The content of the charge generation material is preferably in the range of 50 to 500 parts by weight, and more preferably 100 to 300 parts by weight, based on 100 parts by weight of the binder resin in the charge generation layer. When the content of the charge generating material is less than 50 parts by weight, the charge generating ability of the resulting photoreceptor is small, and when the content of the charge generating material exceeds 500 parts by weight, the mechanical strength of the obtained photoreceptor is low. It may decrease.

[0061] The content of the electron transporting material represented by the above general formula (1) it is preferably is contained in a range of 10 to 100 by weight parts per 100 parts by weight of the binder resin of the charge transport layer , more preferably from 20 to 70 by weight part. If the content of the electron transporting material is less than 10 parts by weight, the sensitivity and repeatability of the resulting photoreceptor will be poor. On the other hand, if the content of the electron transport material exceeds 100 parts by weight, the abrasion resistance of the obtained photoreceptor may be reduced.

The content of the hole transport material represented by the general formula (2) is preferably 10 to 100 parts by weight with respect to 100 parts by weight of the binder resin of the charge transport layer. And more preferably 20 to 70 parts by weight. When the content of the hole transport material is less than 10 parts by weight, the sensitivity of the resulting photoreceptor becomes poor. On the other hand, if the content of the hole transport material exceeds 100 parts by weight, the abrasion resistance of the resulting photoreceptor may be reduced.

The content of the electron transporting material represented by the general formula (1) is 20 to 80% by weight in the charge transporting material.
It is contained, particularly preferably 30 to 70% by weight. When the content of the electron transporting material in the charge transporting material is less than 20% by weight, the sensitivity of the obtained photoreceptor,
Repeatability deteriorates. On the contrary, when the content of the electron transporting material exceeds 80% by weight, the sensitivity of the obtained photoreceptor becomes poor. Preparation of Photoreceptor When forming each of the above layers by a coating method, the charge generation material, charge transport material, binder resin and the like exemplified above, together with a suitable solvent, in a known method, for example, a roll mill,
Prepare a coating solution by dispersing and mixing with a ball mill, attritor, paint shaker or ultrasonic disperser.
This may be applied and dried by a known means.

As the solvent for forming the coating solution, 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, aromatic hydrocarbons such as benzene, toluene and xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, carbon tetrachloride and chlorobenzene, dimethyl ether, diethyl ether and tetrahydrofuran. Examples include ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether, ketones such as acetone, methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and methyl acetate, dimethylformaldehyde, dimethylformamide and dimethyl sulfoxide. These solvents can be used alone or in combination of two or more.

Further, in order to improve the dispersibility of the charge transport 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. Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.

[0066]

【Example】

Synthesis Example 1 3,5-diisopropyl-3 ^, -tert-butyl-5 ^, -
Synthesis of phenyl-4,4 ^, -diphenoquinone 500 equipped with oxygen gas introduction pipe, waste gas discharge pipe, and stirrer
In a milliliter separable flask, 7.8 g of 2,6-diisopropylphenol, 2-tertbutyl-6-
Phenylphenol 9.94g, cuprous chloride 0.18
g, tetramethylethylenediamine (0.414 g) and methanol (100 ml) were charged, and after the reaction was completed while flowing pure oxygen gas into the gas phase of the flask with vigorous stirring, the precipitated crystals were separated by filtration, washed with water and dried. Then,
It was separated by column chromatography packed with silica gel to obtain the target compound represented by the following general formula (c). The yield of the target product was 4.9 g (yield 27%).

[0067]

[Chemical 14]

Synthesis Example 2 Synthesis of 3,5-diisopropyl-3 ^, -(α, α, γ, γ-tetramethylbutyl) -5 ^, -phenyl-4,4 ^, -diphenoquinone , 6-diisopropylphenol and 2- (α, α, γ, γ-tetramethylbutyl) -6-phenylphenol were used and reacted in the same manner as in Synthesis Example 1 to obtain the object represented by the following general formula (d). I got the thing. The yield of the target product is 6.4 g (yield 32
%)Met.

[0069]

[Chemical 15]

Synthesis Example 3 3,5-di (tert-butyl) -3 ^, -tert-butyl-5 ^,
Synthesis of -phenyl-4,4 ^, -diphenoquinone Similar to Synthesis Example 1 except that 2,6-di (secondary butyl) phenol and 2-tertbutyl-6-phenylphenol were used as the disubstituted phenol as a raw material. To obtain the target compound represented by the following general formula (b).

[0071]

[Chemical 16]

Examples 1 to 9 and Comparative Examples 1 to 7 5 parts by weight of charge generating material, 40 parts by weight of electron transporting material, 40 parts by weight of hole transporting material, 100 parts by weight of polycarbonate resin as a binder resin, and as a solvent. A fixed amount of dichloromethane was mixed and dispersed with a ball mill to prepare a coating liquid for a single layer type photosensitive layer. The prepared solution was applied on an aluminum sheet with a wire bar and then dried with hot air at 100 ° C. for 60 minutes to obtain an electrophotographic photosensitive member having a single-layer type photosensitive layer having a film thickness of 15 to 20 μm.

The charge generating material used is represented by the following formula (I):
Compound No. I of (II) I: X-type metal-free phthalocyanine (IP = 5.3
8 eV) II: oxotitanyl phthalocyanine (IP = 5.32)
eV) The hole transport material used is a compound number of the following formulas (A) to (E).

[0074]

[Chemical 17]

The electron-transporting materials used are those represented by the above formulas (a) to (a).
It shows concretely in Table 3 using the compound number of (d). The following tests were carried out on the electrophotographic photoreceptors of the above-mentioned respective Examples and Comparative Examples, and their characteristics were evaluated. Electrical characteristics Electrostatic copying tester (EPA-810, Kawaguchi Denki KK)
0), an applied voltage of ± 7 KV was applied to the surface of the sheet-shaped electrophotographic photoconductors prepared in Examples and Comparative Examples to positively or negatively charge the surface potential to obtain an initial surface potential V1.
(V) was measured. Then, using a halogen lamp as an exposure light source, white halogen light was irradiated for an exposure time of 6 seconds to measure the half-dose exposure amount. That is, the initial surface potential V1
The half-exposure dose (μJ / cm ² ) was determined by determining the time until (V) became 1/2. Further, the surface potential at the time point 3 seconds after the start of exposure was determined as the initial residual potential V2 (V).

The above results are shown in Table 3. Repetitive characteristics The electrophotographic photoreceptors obtained in each of the above Examples and Comparative Examples,
Each of them was attached on an aluminum cylinder with an adhesive tape and then mounted on an electrostatic copying machine DC-1656 (manufactured by Mita Industry Co., Ltd.).

Next, the copying is repeated 1000 times, and then the surface potential V1 '(V) and the post-exposure potential V2' are obtained.
(V) was measured using a surface electrometer, and the difference between the initial surface potential and the initial residual potential was calculated using the following formula. (However, the measurement was performed with positive charging.)

[0078]

[Equation 1]

The above results are shown in Table 3.

[0080]

[Table 3]

As is clear from Table 3, the electrophotographic photosensitive members of the present invention represented by Examples 1 to 9 are excellent in post-exposure potential, half-exposure amount and repetitive characteristics. It can be seen that the photographic characteristics show high performance.
On the other hand, the electrophotographic photoreceptors represented by Comparative Examples 1 to 7 had high post-exposure potential and poor sensitivity, and further had extremely poor repeatability.

[0082]

According to the present invention, by selecting the diphenoquinone derivative represented by the general formula (1) as the electron transport material and the compound represented by the general formula (2) as the hole transport material, An organic photoreceptor having excellent electrophotographic characteristics can be provided.

[Procedure amendment]

[Submission date] October 7, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0073

[Correction method] Change

[Correction content]

The charge generating material used was a compound shown in (I) below: I: X-type metal-free phthalocyanine (IP = 5.38)
eV) The hole transport material used is a compound number of the following formulas (A) to (E).

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masato Katsukawa 1-2-2 Tamatsukuri Chuo-ku, Osaka-shi, Osaka Mita Industry Co., Ltd.

Claims (1)

[Claims] 1. A compound represented by the following general formula (1) as an electron transport material on a conductive substrate: (In the formula, R1, R2, R3 and R4 represent a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group or an aryl group, provided that two of R1, R2, R3 and R4 are the same. And a diphenoquinone compound represented by the following general formula (2) as a hole transport material: (Wherein R5, R6, R7, R8, R9 and R10
Are each independently an alkyl group, an alkoxy group, a halogen atom, an aryl group, a nitro group, a cyano group or an alkylamino group. p and q show the integer of 0-4.
k, l, m and o represent an integer of 0-5. An electrophotographic photosensitive member comprising a photosensitive layer containing a compound represented by the formula (1).