JPH06194853A - Electrophotographic organic photoreceptor - Google Patents

Abstract

PURPOSE:To impart static charge characteristics and characteristics against repeated uses similar to conventional ones and to improve sensitivity and residual potential by incorporating a specified diphenoquinone derivative. CONSTITUTION:The electrophotographic photoreceptor contains in the organic photosensitive layer at least one of the diphenoquinone derivatives represnted by formulae I-III in which each of R1-R3 is, independntly, H, or optionally substituted alkyl, alkoxy, aryl, or aralkyl. The organic photosensitive layer has an electric charge generating material dispersed into a medium containing a charge transfer material and at least one of the charge transfer materials is one of the diphenoquinone derivatives of formulae I-III, thus permitting these derivatives to impart static charge characteristics and characteristics against repeated uses similar to the conventional ones, and to remarkably improve sensitivity and residual potential.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic photoconductor for electrophotography used in copying machines, laser printers and the like, and more specifically, it contains a specific diphenoquinone derivative and is excellent in sensitivity and residual potential. The present invention relates to an electrophotographic photoreceptor.

[0002]

2. Description of the Related Art A light source having a wavelength of 700 nm or more is usually used for an electrophotographic photosensitive member using a digital optical system. Organic photoreceptors (OPC), amorphous silicon (α-S) are used as photoreceptors having sensitivity in this wavelength region.
i), some selenium photoreceptors are known, but the sensitivity,
From a comprehensive viewpoint of cost, etc., OPC is often used in this field.

As an organic photoreceptor, a charge generation layer (CG
L) and a charge transport layer (CTL) are laminated, so-called function-separated type organic photoconductors, that is, multi-layered photoconductors are often used, but a single layer type in which a charge generating agent is dispersed in a medium of the charge transporting agent is used. Organic photoconductors are already known. As a charge transfer agent for this type of photoconductor, one having a high carrier mobility is required, but most of the charge transfer agents having a high carrier mobility have a hole transporting property, and thus are practically used. The thing is limited to the negative charge type organic photoreceptor. However, since the negatively charged organic photoreceptor uses a negatively charged corona discharge, a large amount of ozone is generated, which causes problems such as pollution of the environment and deterioration of the photoreceptor. It requires a special charging system that does not generate electricity, a system that decomposes generated ozone, a system that exhausts ozone in the apparatus, and the like, which has the drawback of complicating the process and system. In addition, the laminated type photoreceptor has an optical problem that interference fringes are easily generated because the photosensitive layer needs to be coated twice or the photosensitive layer has an interface between the charge generation layer and the charge transport layer. .

As one of the few examples of a charge transfer agent having an electron transfer ability, JP-A-1-206349 proposes a compound having a diphenoquinone structure as a charge transfer agent for an electrophotographic photoreceptor.

[0005]

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

That is, an object of the present invention is to provide an electrophotographic photosensitive member having high sensitivity. Another object of the present invention is to
Another object of the present invention is to provide an electrophotographic photosensitive member which contains a specific diphenoquinone derivative as an electron transfer material and can be positively charged and the copying speed can be increased in an image forming apparatus.

[0007]

According to the present invention, the organic photosensitive layer contains at least one diphenoquinone derivative represented by the following general formula (1), (2) or (3). An organic photoconductor for electrophotography is provided.

[0008]

[Chemical 3]

(In the formula, R1, R2 and R3 each independently represent a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group, an aryl group or an aralkyl group.) According to the present invention, In an organic electrophotographic photoreceptor for electrophotography, which comprises a photosensitive layer in which a charge-generating agent is dispersed in a medium containing the charge-transporting agent, at least a part of the charge-transporting agent is represented by the general formula (1), (2) or (3). An electrophotographic photoreceptor is provided which is a diphenoquinone derivative represented by:

In the above photoconductor, it is desirable that the charge generating agent has an ionization potential of 5.3 to 5.6 eV.

[0011]

According to the present invention, the diphenoquinone derivative having the structure represented by the general formula (1), (2) or (3) maintains the charging characteristics and the repeating characteristics almost the same as those of the diphenoquinone derivative known as an electron transfer agent. , And is based on the finding that it exhibits markedly improved sensitivity and residual potential.

Conventionally, more soluble in the solvent, thus compatibility with the binder resin is good, and moreover the best diphenoquinone derivatives in the electron transport performance, ^{_{3,5-dimethyl-3,}}
5 ^, -ditert-butyl-4,4 ^, -diphenoquinone (DMDB), that is, the following formula (a)

[0013]

[Chemical 4]

Derivatives of are known. This DMDB
Among the diphenoquinone derivatives, it has high charging characteristics and excellent sensitivity, but it is necessary to improve the sensitivity in order to use it in a high-speed copying machine or the like, and it is still satisfactory in practical use. Not a thing. On the other hand, when the diphenoquinone derivative having the structure represented by the general formula (1), (2) or (3) is used according to the present invention, the sensitivity is maintained while maintaining the charging characteristics and the repeating characteristics at the same level as DMDB. And the residual potential can be significantly improved (see the example described later).

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

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Electron Transfer Agent In the diphenoquinone derivative represented by the general formula (1), (2) or (3), the alkyl group corresponding to R1 to R3 in the formula is a methyl group or an ethyl group. Group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, 2-ethylhexyl group, etc. primary alkyl group having up to 9 carbon atoms, isopropyl group, sec-butyl group, etc. 9 secondary alkyl group, t-butyl group, α, α,
Examples thereof include alkyl groups having 4 to 9 carbon atoms such as γ and γ-tetramethylbutyl groups.

As the alkoxy group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a t-butoxy group,
Examples thereof include a hexyloxy group and a 2-ethylhexyl group, with a methoxy group and an ethoxy group being preferred. Examples of the aryl group include a phenyl group, an o-terphenyl group, a naphthyl group, a tolyl group, an ethylphenyl group, an anthryl group, a phenanthryl group, and the like, and an aryl group having 6 to 16 carbon atoms is preferable. Examples of the aralkyl group include a benzyl group, a phenethyl group and a cumyl group.

As the substituent for substituting the above group, for example, a halogen atom, an amino group, a hydroxyl group, an optionally esterified carboxyl group, a cyano group, an alkyl group having 1 to 6 carbon atoms, or an aryl group is included. Some carbon number 2-6
Alkenyl groups and the like. The general formula (1),
Specific examples of the diphenoquinone derivative represented by (2) or (3) include compounds having groups shown in Tables 1 and 2 as the groups of R1 to R3 in each formula.

[0019]

[Table 1]

[0020]

[Table 2]

Further, the above general formulas (1), (2) and (3)
The diphenoquinone derivative represented by can be synthesized by various conventionally known methods. For example, the diphenoquinone derivative represented by the general formula (1) is represented by the following formula (i)

[0022]

[Chemical 5]

(Wherein R1 represents a group similar to the above formula (1)) and a disubstituted phenol represented by the following formula (i)
i)

[0024]

[Chemical 6]

(Wherein R2 and R3 represent the same groups as those in the above formula (1).) A disubstituted phenol represented by the formula (1) is molecularly prepared in a polar solvent in the presence of a copper salt-tertiary amine complex catalyst. It can be synthesized by contacting with oxygen. The diphenoquinone derivative represented by the general formula (2) is the same as the disubstituted phenol represented by the following formulas (iii) and (iv) in place of the formulas (i) and (ii). It can be synthesized in the same manner as described above.

[0026]

[Chemical 7]

(In the formula, R1, R2 and R3 represent the same groups as those in the above formula (2).) The diphenoquinone derivative represented by the above general formula (3) is represented by the above formulas (i) and (ii). Instead of, a disubstituted phenol represented by the following formulas (v) and (vi) is used, and it can be synthesized in the same manner as above.

[0028]

[Chemical 8]

(In the formula, R1, R2 and R3 represent the same groups as in the above formula (3).) The diphenoquinone derivative represented by the above general formula (1), (2) or (3) may be used alone. Alternatively, they may be mixed and used. Hole Transfer Agent As the hole transfer agent, any hole transfer agent is used, and examples thereof include oxadiazole compounds, styryl compounds, carbazole compounds, pyrazoline compounds, hydrazone compounds, triphenylamine compounds, Indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds,
Of the nitrogen-containing cyclic compounds and condensed polycyclic compounds such as imidazole compounds, pyrazole compounds, and triazole compounds, the ionization potential is 5.3 ev to 5.6 e.
V (the measurement is carried out by an atmospheric photoelectron analyzer (AC-1 by Riken Keiki Co., Ltd.)) is preferably used.
Suitable hole transport agents include, but are not limited to, 1,1-
Bis (p-diethylaminophenyl) -4,4 diphenyl-1,3-butadiene (IP = 5.32 eV, drift mobility = 7.5 × 10 ⁻⁶ cm ² / V · sec), N,
N ^, -bis (o, p-dimethylphenyl) -N, N ^, -diphenylbenzidine (IP = 5.43 eV, drift mobility = 2.8 × 10 ⁻⁵ cm ² / V · sec), 3,3 ^,
- dimethyl -N, N, ^{N,, N,} - tetrakis-4-methylphenyl ^(1,1, - biphenyl) ^-4,4' - diamine (IP = 5.56eV, drift mobility = 5.1 ×
10 ⁻⁵ cm ² / V · sec), N-ethyl-3-carbazolylaldehyde-N, N ^, -diphenylhydrazone (IP = 5.53 eV, drift mobility = 3.2 × 10)
^-5 cm ² / V · sec), 4- [N, N-bis (p-toluyl) amino] -β-phenylstilbene (IP =
5.53 eV, drift mobility = 3.5 × 10 ⁻⁵ cm ²
/ V · sec) and the like. Charge Generating Agent As the charge generating agent, any charge generating agent is used, including selenium, selenium-tellurium, amorphous silicon, pyrylium salts, azo pigments, disazo pigments, anthanthrone pigments, phthalocyanine pigments, indico pigments. Examples thereof include threnic pigments, toluidine pigments, pyrazoline pigments, perylene pigments, quinacridone pigments and the like, and they may be used alone or in combination of two or more so as to have an absorption wavelength in a desired region. Ionization potential is 5.3 ev
To 5.6 eV [measured by an atmospheric photoelectron analyzer (AC-1) manufactured by Riken Keiki Co., Ltd.] is preferable, and the following are particularly preferable. 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 (IP = 5.60eV ) Binder resin As the binder resin, various kinds of resins can be used,
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, polyester Thermoplastic resin such as resin, silicone resin, epoxy resin, phenol resin, urea resin, melamine resin, other crosslinkable thermosetting resin, and photocurable epoxy acrylate, urethane-acrylate, etc. Butter, and the like are exemplified. These binder resins can be used alone or in combination of two or more. In the additive photosensitive layer, within a range that does not adversely affect electrophotographic properties, various kinds of compounding agents known per se, for example, antioxidants,
A radical scavenger, a singlet quencher, a UV absorber, a softening agent, a surface modifier, a thickener, a dispersion stabilizer, a wax, an acceptor, a donor and the like can be added.

According to the present invention, when a sterically hindered phenolic antioxidant is added in an amount of 0.1 to 50% by weight based on the total solid content, the durability of the photosensitive layer is remarkably improved without adversely affecting the electrophotographic characteristics. I found that it can be improved. Suitable antioxidants are as follows:

[0031]

[Chemical 9]

[0032]

[Chemical 10]

Conductive Substrate As the conductive substrate on which the photosensitive layer is formed, various conductive materials can be used, such as aluminum,
Copper, tin, platinum, silver, vanadium, molybdenum, chromium,
Examples include cadmium, titanium, nickel, palladium, indium, stainless steel, brass and other simple metals, plastic materials obtained by vapor deposition or lamination of the above metals, aluminum iodide, tin oxide, glass coated with indium oxide, etc. It

It may be in the form of a conductive 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. 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 above general formulas (1) and (2)
Alternatively, the effect of the electron transfer agent represented by (3) becomes more prominent particularly in the single-layer type photosensitive layer containing the charge generation agent, the hole transfer agent and the electron transfer agent in the same layer. ,
It can be said that the present invention is more preferably applied to an electrophotographic photoreceptor having a single-layer type photosensitive layer.

To obtain a single-layer type photoreceptor, a compound represented by the general formula (1), (2) or (3), which is a charge generating agent and an electron transferring material, is combined with a hole transferring material. A photosensitive layer containing a resin and the like may be formed on the conductive substrate by means of coating or the like. That is, the principle of generating a charge image in the above single layer system is that, when charges (holes / electrons) are generated in the charge generating agent by exposure, the individual agents are contained in the same layer.
There are more opportunities for contact between the charge generation agent and the charge transfer agent, and electrons are efficiently injected into the electron transfer agent, holes are injected into the hole transfer agent,
The respective charges (holes / electrons) injected thereafter are transferred in the respective transport agents without being trapped on the way, and finally transported to the surface of the photosensitive layer or the conductive substrate side. .

That is, in the single-layer type photoconductor as described above,
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 generation layer containing a charge generation agent is formed on a conductive substrate by means such as vapor deposition or coating, and the electron transfer agent, which is an electron transfer agent, is formed on the charge generation layer. The charge transport layer containing the compound represented by the general formula (1), (2) or (3), the hole transport agent and the 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 charge generation layer containing a charge generation agent is formed on a conductive substrate by means such as vapor deposition or coating, and the electron transfer agent represented by the general formula (1), (2) or The electron transport layer containing the compound represented by (3) and the 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 may be sequentially laminated. The laminated type photoreceptor of the above type is a negative charging type. Further, a protective layer may be provided on the organic photosensitive layer, or an intermediate layer may be provided between the 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. When the organic photosensitive layer is formed as a laminate, the charge generation layer has a thickness of 0.
1 to 5 μm is preferable, and more preferably 0.5 μm to
2 μm. The thickness of the charge transport layer is preferably 10 to 50 μm, more preferably 15 to 60.

In the photoconductor of the present invention, the charge generating agent is 0.1 to 5% by weight, particularly 0.25 to 2.
It is preferably contained in the photosensitive layer in an amount of 5% by weight. When the content of the charge generating agent is less than 0.1% by weight, the photosensitivity of the resulting photoreceptor becomes insufficient. On the contrary, when the content of the charge generating agent exceeds 5% by weight, the charging property and the repeating property of the obtained photoreceptor are deteriorated.

The diphenoquinone derivative (ET) as an electron transfer agent is preferably used in an amount of 5 to 50% by weight, particularly 10 to 40% by weight, based on the solid content. When the content of the above diphenoquinone derivative is less than 5% by weight, the photosensitivity of the resulting photoreceptor becomes insufficient. On the contrary, when the content of the above diphenoquinone derivative exceeds 50% by weight, the resulting photoreceptor will be crystallized.

On the other hand, when a hole transporting agent (HT) is used in combination, it is 5 to 50% by weight, particularly 20 to 40% by weight based on the solid content.
It is preferable that each of them is contained in the photosensitive layer in a weight percentage. When the content of the hole transport material is less than 5% by weight, the photosensitivity of the resulting photoreceptor is not sufficient. On the contrary, when the content of the hole transporting agent exceeds 50% by weight, the resulting photoreceptor will be crystallized. Further, the ET: HT weight ratio is best in the range of 1: 9 to 9: 1, especially 2: 8 to 8: 2. Preparation of Photoreceptor When the above layers are formed by a coating method, the charge generation agent, electron transfer agent, hole transfer agent, binder resin and the like exemplified above are used together with a suitable solvent in a known method, for example, A coating solution may be prepared by dispersing and mixing using a roll mill, a ball mill, an attritor, a paint shaker or an ultrasonic disperser, and the coating solution may be coated and dried by a known means.

As the solvent for forming the coating solution, various kinds of 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, tetrahydrofuran, Examples thereof 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 may be used alone or in combination of two or more.

The present invention will be described in detail below with reference to Examples and Comparative Examples.

[0045]

【Example】

Synthesis Example 1 Synthesis of 3,5-diisopropyl-3 ^, -t-butyl-5 ^, -phenyl-4,4 ^, -diphenoquinone 500 equipped with an oxygen gas introduction pipe, a waste gas discharge pipe, and a stirrer
A milliliter separable flask was charged with 7.8 g of 2,6-diisopropylphenol, 9.94 g of 2-t-butyl-6-phenylphenol, 0.18 g of cuprous chloride, 0.414 g of tetramethylethylenediamine, and 100 ml of methanol. After the reaction was completed while flowing pure oxygen gas into the flask gas phase while stirring vigorously, the precipitated crystals were separated by filtration, washed with water and dried. Then, the product 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%).

[0046]

[Chemical 11]

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 reacted in the same manner as in Synthesis Example 1 except that the target compound represented by the following general formula (d) was used. Got The yield of the target product is 6.4 g (yield 32
%)Met.

[0048]

[Chemical 12]

Synthesis Example 3 Synthesis of 3,5-di (tertiary butyl) -3 ^, -t-butyl-5 ^, -phenyl-4,4 ^, -diphenoquinone As the disubstituted phenol as a raw material, 2,6-di ( A reaction product was obtained in the same manner as in Synthesis Example 1 except that (tert-butyl) phenol and 2-t-butyl-6-phenol were used to obtain the target compound represented by the following general formula (b).

[0050]

[Chemical 13]

Synthetic Example 4 Synthesis of 3,5-dimethoxy-3 ^, -(α, α, γ, γ-tetramethylbutyl) -5 ^, -phenyl-4,4 ^, -diphenoquinone , 6-dimethoxy-
Reaction was performed in the same manner as in Synthesis Example 1 except that phenol and 2-phenyl-6- (α, α, γ, γ-tetramethylbutyl) -phenol were used to obtain the target compound represented by the following general formula (e). .

[0052]

[Chemical 14]

Synthesis Example 5 3,5-Dimethyl-3 ^, -(tert-butyl) -5 ^, -(α-
Synthesis of dimethyl-benzyl) -4,4 ^, -diphenoquinone Other than using 2,6-dimethyl-phenol and 2- (α-dimethyl-benzyl) -6- (tert-butyl) phenol as the disubstituted phenol as a raw material. Was reacted in the same manner as in Synthesis Example 1 to obtain the target compound represented by the following general formula (f).

[0054]

[Chemical 15]

Single-layer type electrophotographic photoconductors Examples 1 to 36 and Comparative Examples 1 to 8 5 parts by weight of charge generating agent, 40 parts by weight of electron transferring material, 40 parts by weight of hole transferring material, and polycarbonate as a binder. 10
A coating solution for a single-layer type photosensitive layer was prepared by mixing and dispersing 0 part by weight and a predetermined amount of dichloromethane as a coating solvent with a ball mill, and the prepared solution was coated on an aluminum foil with a wire bar and then at 100 ° C. By hot air drying for 60 minutes, a single-layer type electrophotographic photosensitive member having a film thickness of 15 to 20 μm was obtained. The charge generating agent used was compound number I of the following I and II: X-type metal-free phthalocyanine (IP = 5.3
8 eV) II: oxotitanyl phthalocyanine (IP = 5.32)
eV) The hole transfer agent used is a compound number of the following general formulas (A) to (E).

[0056]

[Chemical 16]

The electron transfer agent used is represented by the above formula (a) to
Specific examples are shown in Table 3 using the compound numbers of (f). Laminated electrophotographic photoreceptors Examples 37-57 and Comparative Examples 9-13 100 parts by weight of a charge generating agent, 100 parts by weight of butyral resin as a binder, and a predetermined amount of tetrahydrofuran as a solvent were mixed and dispersed in a ball mill, A charge generation layer coating solution is prepared, and the prepared solution is applied on an aluminum foil with a wire bar, and then dried with hot air at 100 ° C. for 60 minutes to form a charge generation layer having a film thickness of 1 to 2 μm. 40 parts by weight of a transfer material, 40 parts by weight of a hole transfer material, 100 parts by weight of a polycarbonate as a binder, and a predetermined amount of toluene as a solvent were mixed and dispersed by a ball mill to prepare a coating solution for a charge transfer layer. The solution was applied with a Royer bar and then dried with hot air at 100 ° C. for 60 minutes to obtain a laminated electrophotographic photosensitive member having a film thickness of 15 to 20 μm. The charge generating agent, hole transporting agent, and electron transporting agent used are the same as those used in the above single-layer type electrophotographic photoreceptor, and are specifically shown in Table 4.

The following tests were carried out on the electrophotographic photoreceptors of the above-mentioned respective Examples and Comparative Examples to evaluate their characteristics. 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, a white halogen lamp light was irradiated for an exposure time of 6 seconds to measure the half-dose exposure amount. That is, the time until the initial surface potential V1 (V) becomes 1/2 was obtained, and the half-dose exposure amount (μJ / cm ² ) was obtained. Also, 3 from the start of exposure
The surface potential after the lapse of seconds was determined as the initial residual potential V2 (V). Repeatability Characteristics The electrophotographic photoreceptors obtained in each of the above Examples and Comparative Examples were attached on aluminum cylinders using adhesive tapes, and then mounted on an electrostatic copying machine DC-1656 (manufactured by Mita Industry Co., Ltd.). did.

Next, the copying is repeated 1000 times, and the surface potentials V1 ^and (V) and the post-exposure potential V2 after that are repeated.
^, (V) were measured in the same manner as above, and the difference between the initial surface potential and the initial residual potential was calculated using the following formula.

[0060]

[Equation 1]

The above results are shown in Tables 3 and 4.

[0062]

[Table 3]

[0063]

[Table 4]

As is clear from Table 3, Examples 1-36
The single-layer type electrophotographic photoconductor of the present invention shown in FIG. 2 is capable of being charged both positively and negatively, and is excellent in sensitivity, residual potential, and repetitive characteristics, and particularly, the characteristics of the sensitivity side are remarkably improved. . On the other hand, the positively charged single-layer type photoreceptors shown in Comparative Examples 1 to 4 are compared with Examples 1 to 15 and Examples 19 to 33, and the negatively charged single layer type photoreceptors shown in Comparative Examples 5 to 8. The layer type photoreceptor was inferior in sensitivity, residual potential and repetitive characteristics as compared with Examples 16 to 18 and Examples 22 to 24.

Next, as is clear from Table 4, Example 3
The laminated photoreceptors of the present invention shown in Nos. 7 to 57 were excellent in sensitivity, residual potential and repeatability. On the other hand, the positively charged laminated type photoreceptors shown in Comparative Examples 9 to 11 were compared with Examples 37 to 51, and the negatively charged laminated type photoreceptor shown in Comparative Example 12 was compared with Example 52. Comparative Example 1
The positively charged layered type photoreceptor not containing the hole transfer agent shown in No. 3 was inferior to Examples 53 to 57 in sensitivity, residual potential and repeatability.

[0066]

According to the present invention, among the diphenoquinone derivatives, at least one of the specific diphenoquinone derivatives represented by the general formula (1), (2) or (3) is selected, and this is used as an organic photosensitive layer. By using it as an electron transfer agent, it was possible to obtain charging characteristics and repetitive characteristics which were not inferior to those using the conventional diphenoquinone derivative, and at the same time, significantly improved sensitivity and residual potential could be obtained.

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

[Procedure amendment]

[Submission date] October 5, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Chemical 1] (In the formula, R 1, R 2, and R 3 are different from each other, a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group,
An aryl group and an aralkyl group are shown. )

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Chemical 2] (In the formula, R 1, R 2, and R 3 are different from each other, a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group,
An aryl group and an aralkyl group are shown. )

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

(In the formula, R1, R2, and R3 are different from each other.
And represents a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group, an aryl group or an aralkyl group. ) According to the present invention, in an electrophotographic organic photoreceptor having a photosensitive layer in which a charge generating agent is dispersed in a charge transporting agent-containing medium, at least a part of the charge transporting agent is represented by the general formula (1), There is provided an organic photoconductor for electrophotography, which is a diphenoquinone derivative represented by (2) or (3).

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

Claims (5)

[Claims] 1. An organic photosensitive layer comprising the following general formula (1):
An organic photoconductor for electrophotography, comprising at least one diphenoquinone derivative represented by (2) or (3). [Chemical 1] (In the formula, R1, R2, and R3 are each independently a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group,
An aryl group and an aralkyl group are shown. ) 2. An organic photosensitive layer, in which at least one diphenoquinone derivative represented by the following general formula (1), (2) or (3) as an electron transfer agent dispersed in a resin medium, a charge generating agent and The organophotoreceptor for electrophotography according to claim 1, which is a composition comprising a hole transport material. [Chemical 2] (In the formula, R1, R2, and R3 are each independently a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group,
An aryl group and an aralkyl group are shown. ) 3. The charge-generating agent is a charge-generating agent having an ionization potential of 5.3 to 5.6 eV.
2. The electrophotographic photoreceptor for electrophotography according to 2. 4. The organic photoconductor for electrophotography according to claim 1, wherein the charge generating agent is an X-type metal-free phthalocyanine. 5. The organic photoreceptor for electrophotography according to claim 1, wherein the charge generating agent is present in the organic photosensitive layer in an amount of 0.1 to 5% by weight based on the solid content.