JPS63175860A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the electrophotographic characteristics of the titled body by incorporating a specific diphenyldicyanoethylene derivative to an electric charge transfer layer. CONSTITUTION:The titled body comprises an electric charge generating layer and the electric charge transfer layer provided on a conductive supporting body. In the formula R1 is hydrogen atom, nitro or alkoxycarbonyl group, R2 is alkyl, alkoxy, nitro, cyano or alkoxy carbonyl group, R3 is hydrogen or halogen atom, alkoxy carbonyl or nitro group, R4 is hydrogen or halogen atom, alkyl, cyano, nitro, alkoxy carbonyl, a substd. or an unsubstd. phenyl or a substd. or an unsubstd. 4-phenyl phenyl group. Said diphenyl dicyanoethylene derivative has an electron transferring property more than equivalent to that of 2,4,7-trinitrofluorenone (TNF). Accordingly, the positive charge electron photographic sensitive body in which said derivative is used to the electron transfer agent of the charge transfer layer has the excellent electrophotographic characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrophotographic photoreceptor having a charge generation layer and a charge transport layer.

Conventional technology Conventionally, electrophotographic photoreceptors using organic photoconductors have been studied in various ways because they have advantages such as non-pollution, high productivity, and low cost. There are also known methods using
@Refer to the official bulletin).

However, among organic photoconductors, substances that absorb visible light and generate electric charge have poor charge retention ability; It has the disadvantage that it has almost no photoconductivity. In order to solve this problem, we developed a laminated photosensitive layer that has a layer structure in which the photosensitive material is functionally separated into a charge generating agent that absorbs visible light and generates a charge, and a charge transport material that transports the charge. things are being done. Many charge generating agents and electron transporting agents have been proposed, including amine compounds, hydrazone compounds,
Pyrazoline compounds, oxazole compounds, oxadiazole compounds, stilbene compounds, carbazole compounds, etc. are known.

Problems to be Solved by the Invention Incidentally, in a function-separated type electrophotographic photoreceptor, a positively charged type is preferable from the viewpoints of prevention of ozone generation in a corotron, control of toner charge during development, and the like. However, when used as a positively charged type, if the electron transport agent has hole transport properties, it is necessary to provide a charge generation layer as an upper layer, but due to its nature, the charge generation layer is usually made thin. This is insufficient to satisfy the mechanical properties of a photoreceptor. In addition, it is necessary to devise measures on the copying machine side for use with negative charging. Therefore, there is a desire to obtain a positively charged photoreceptor by using a relatively thick charge transport layer as an upper layer, and for this purpose, it is necessary to use a sufficiently effective electron transport agent in the charge transport layer. be. However, none of the previously proposed electron transport agents is known to be sufficiently effective.

The present invention has been made in view of the above-mentioned conventional problems.

Therefore, an object of the present invention is to provide a laminated electrophotographic photoreceptor for positive charging that has excellent electrophotographic properties.

Means for Solving the Problems As a result of research, the present inventors have found that when a group of diphenyldicyanoethylene derivatives are used as a charge transport agent, a positively charged electrophotographic photoreceptor exhibiting good electrophotographic properties can be obtained. They discovered this and completed the present invention.

The electrophotographic photoreceptor of the present invention has a charge generation layer and a charge transport layer on a conductive support, and the charge transport layer contains a diphenyldicyanoethylene derivative represented by the following general formula (I>). It is characterized by

(In the formula, R1 represents a hydrogen atom, a nitro group, or an alkoxycarbonyl group, and R2 represents an alkyl group, an alkoxy group,
Represents a nitro group, a cyano group, or an alkoxycarbonyl group, R3 represents a hydrogen atom, an alkoxycarbonyl group, a halogen atom, or a nitro group, and R4 represents a hydrogen atom, an alkyl group, a cyano group, a nitro group, a halogen atom, or an alkoxycarbonyl group. , represents a substituted or unsubstituted phenyl group or a substituted or unsubstituted 4-phenylphenyl group. ) Examples of the compound represented by the above general formula used in the present invention include the following.

(5> (6) (11)
(12>(13)
<14>('+5)
(16) (23)
(2/I) (3g>
(40)(/13)
(/I4>(bl) (5
2) (5ri) (b6
) ”3<b9)
(60) These compounds can be synthesized, for example, by condensation reaction of the corresponding benzophenone derivative with malonitrile in a solvent, optionally in the presence of a catalyst, at temperatures from 50 °C to the boiling point of the solvent. can. This reaction is a dehydration condensation reaction between a carbonyl group and an active methylene.
This is known as the e + reaction. (Experimental Chemistry Course 1
Volume 8 “Reactions of Organic Compounds ■ (Medium)” (Nippon Kagaku Kinpei, 1
In the electrophotographic photoreceptor of the present invention, examples of the conductive support include metal pipes, metal plates, metal sheets, metal foils, conductive-treated polymer films, AI, etc. A polymer film provided with a metal vapor deposited layer, a polymer film or paper coated with a metal oxide quaternary ammonium salt such as 5n02, etc. are used.

The charge generation layer formed on the conductive support may be obtained, for example, by vapor-depositing a charge generation agent on the conductive support, or it may be formed mainly of a charge generation agent and a binder resin. It may be formed by applying a coating liquid.

As the charge generating agent and binder resin, any known ones may be used.
You can use anything. For example, as the charge generating material, inorganic semiconductors such as tri-3e, organic semiconductors such as polyvinylcarbazole, organic pigments such as bisazo compounds, trisazo compounds, phthalocyanines, pyrylium compounds, and squareium compounds can be used. As the binder resin, polystyrene, silicone resin,
Polycarbonate resins, acrylic resins, methacrylic resins, polyesters, vinyl polymers, celluloses, alkyd resins, etc. can be used.

The thickness of the charge generation layer is set to about 0.05 to 10 μm.

A charge transport layer is formed on the charge generation layer.

This charge transport layer is composed of the above-mentioned diphenyldicyanoethylene derivative and a binder resin. ,
It is formed by coating on the charge generation layer using a dip coater or the like. In this case, the mixing ratio of the diphenyldicyanoethylene derivative and the binder resin is 1:20 to 20.
: Set to about 1. In addition, the thickness of the charge transport layer is 2 to 2.
It is set to about 100μ.

Any known binder resin can be used for the charge transport layer. For example, styrene-butadiene copolymer, vinyltoluene-styrene copolymer, styrene-modified alkyd resin, silicone-modified alkyd resin, soybean oil-modified alkyd resin, nyldene chloride-vinyl chloride copolymer, polyvinyl butyral, nitrated polystyrene, Methylstyrene, polyisobutylene, polyester, phenolic resin, ketone resin,
Examples include polyamide, polycarbonate, polythiocarbonate, polygonyl haloarylate, vinyl acetate resin, polystyrene, polyvinyl acrylate, polysulfone, and polymethacrylate.

In addition, in the electrophotographic photoreceptor of the present invention, a barrier layer may be provided on the conductive support. The barrier layer is effective in preventing unnecessary charge injection from the conductive support, and has the effect of improving image quality. Materials constituting the barrier layer include metal oxides such as aluminum oxide, acrylic resins, phenolic resins, polyester resins,
Examples include polyurethane.

Examples Hereinafter, synthesis examples of the above-mentioned compounds used in the present invention and examples of the present invention will be shown.

Synthesis Example 1 Synthesis of Exemplified Compound (8) 12.59 of 4-nitrobenzoyl chloride and 93 of aluminum chloride were stirred in 100 rnl of methylene chloride, and a solution of 5.2 g of biphenyl dissolved in 20 m of methylene chloride was slowly added dropwise to the solution. , After the completion of dropping, at room temperature 8
Stir for hours. After the reaction mixture was poured into water, an aqueous sodium hydroxide solution was added to remove the acid chloride. Next, the methylene chloride layer was separated, thoroughly washed with water, dried, and the solvent was distilled off. The obtained residue was recrystallized from methylene chloride-ethanol to obtain 7.59 g of 4-nitro-4-1-phenylbenzophenone.

rrl, 166-167℃ Mass spectrum M''-303 Elemental analysis CHN Calculated value 75.24 4.32 4.62 Actual value
75,13 4.15 4.43I R1650cm
-1(C=O) Next, 6.4 g of the obtained 4-nitro-4'-phenylbenzophenone and 2.5 g of malonitrile were refluxed in 100 d of pyridine under a nitrogen stream for 4 hours. Thereafter, pyridine was distilled off under reduced pressure, and the residue was dissolved in methylene chloride, thoroughly washed with dilute hydrochloric acid and then with water, dried, and methylene chloride was distilled off under reduced pressure. The residue was recrystallized from methanol to yield 1 q of 5.9 g of Exemplified Compound (8).

ml), 169-171°C Mass spectrum M+ 351 Elemental analysis CHN Calculated value 75.21 3.73 11.96 Actual value
75.40 3.52 11.80I R2224c
m-1(-CN) Synthesis Example 2 Synthesis of Exemplified Compound (44) Benzophenone tetracarboxylic dianhydride 109 was suspended in 70 d of methanol, 1 d of concentrated sulfuric acid was added, and 80 d of concentrated sulfuric acid was added.
Refluxed for an hour. Thereafter, it was poured into 150 m of water, made basic by adding sodium carbonate, and extracted with methylene chloride.

After thoroughly washing the methylene chloride layer with water, it was dried, and the methylene chloride was distilled off. After thoroughly drying the residue, add pyridine 100
d, 2.8 g of malonitrile was added thereto, and the mixture was rapidly flowed under a nitrogen stream for 4 hours. Pyridine was distilled off under reduced pressure, and the residue was dissolved in methylene chloride and thoroughly washed with dilute hydrochloric acid and then with water. Then, it was dried over anhydrous sodium sulfate, and methylene chloride was distilled off under reduced pressure.

The residue was recrystallized from methanol-methylene chloride to give exemplified compound (44) 4.1! ? I got it.

mp, 169-171°C Mass spectrum M+ 462 Elemental analysis CHN Calculated value &2.34 3.92 6.06 Actual value
82,52 3.92 6.04I R2220rm
, 1744 cm-1, 1724 cm-1 Synthesis Example 3 Synthesis of Exemplary Compound (1) 10 cj of commercially available 4-nitrobenzophenone and 5.89 g of malonitrile were rapidly flowed in pyridine 1001 ni under a nitrogen stream for 4 hours. Thereafter, pyridine was distilled off under reduced pressure, and the residue was dissolved in methylene chloride, thoroughly washed with dilute hydrochloric acid and then with water, dried, and methylene chloride was distilled off under reduced pressure. The residue was recrystallized from methanol to obtain Exemplified Compound (1)
I got it.

mp, 97.5-98.5℃ (from methanol) Mass spectrum M 275 Elemental analysis CHN Calculated value 69°82 3.30 15.27 Actual value
70.07 3.27 15.211 R2228c
m-1 (KBr) Synthesis Example 4 Synthesis of Exemplified Compound (2) 2-nitrobenzophenone 13.59, malononitrile 7.9 g and pyridine 10 (M!) Compound (2)
I got it.

r7B), 114-115.5°C (from ethanol) Mass spectrum M+ 275 Elemental analysis CHN Calculated value 69.82 3.30 15.27 Actual value
70,14 3.13 15.28I R2224c
m-' (KBr) Synthesis Example 5 Synthesis of Exemplary Compound (15) 4-Ethyl-3-,5-dinitrobenzophenone 1
3.59, malononitrile 5.9g and pyridine 1
Exemplary compound (15) was obtained in the same manner as in Synthesis Example 3 except that 00m was used.

mD, 181-183℃ (from hexane/CH2Cl2) Mass spectrum M+ 348 Elemental analysis CHN Calculated value 82.07 3.47 16.09 Actual value
62.23 3.31 15.98I R2232c
m-' (KBr) Synthesis Example 6 Synthesis of Exemplified Compound (18) 3=, 5''-dinitro-4'-phenylbenzophenone 129, malononitrile 4.6y and pyridine 1
Exemplary compound (18) was obtained in the same manner as in Synthesis Example 3 except that 00ml was used.

mp, 213.5-215.5°C (CH2CI2
/from ethanol) Mass spectrum M 396 Elemental analysis CHN Calculated value 66.68 3.05 14.14 Actual value
66.67 2.89 13.95I R2228c
m-1 (KBr) Synthesis Example 7 Synthesis of Exemplified Compound (47) 3. Exemplified Compound was prepared in the same manner as in Synthesis Example 3, except that 10 g of 3-dinitrobenzophenone, 4.4 g of malononitrile, and 100 g of pyridine were used. (4
7) was obtained.

no, 209-211°C (from CH2CI2) Mass spectrum M+ 320 Elemental analysis CHN Calculated value 60.01 2.52 17.49 Actual value
60.19 2.35 17.58r R2228c
m-'(KBr) The other compounds exemplified above can also be synthesized in the same manner as above.

Example 1 0.5y of Exemplified Compound (1) and 0.75g of bisphenol A polycarbonate (Macrolon 5705) were dissolved in 79g of methylene chloride to obtain a solution (2).

This solution (1) was applied to the 1-ri-3e provided on the conductive substrate.
/ polyvinyl carbazole 70 wt%) on a charge generation layer (2.5 μm),
Apply with a wet gap of 5 ml and apply at 80°C.
After drying for hours, an electrophotographic photoreceptor was obtained. This electrophotographic photoreceptor was tested using an electrostatic copying paper tester (Kawaguchi Electric Seisakusho SP4).
28) to +800V or -800V, and 5 l
Sensitivity dV/dt (initial decay rate) was evaluated by exposing to ux white light. The results are as follows.

dV/dt (initial decay rate) +800 V 509 V/sec-800 V
Comparative Example 1 with No Attenuation The solution (1) prepared in Example 1 was applied onto a conductive substrate with a wet gap of 5rd, and dried at 80'C for 1 hour to obtain a photoreceptor. This was tested at +800V and -800V using an electrostatic copying paper tester (Kawaguchi Riken SP428).
When charged to v and exposed to 5 1uX white light,
No potential attenuation was observed.

Examples 2-6 Exemplary compounds 1) (2), (8), (18), (44
) and (47), a solution having the same composition as in Example 1 was prepared, and an electrophotographic photoreceptor was obtained in the same manner as in Example 1. Comparative Example 2 Compound (1) was evaluated in the same manner as in Example 1.
An electrophotographic photoreceptor was obtained in the same manner as in Example 1 except that a solution having the same composition as in Example 1 was prepared instead of TNF). The sensitivity of the obtained electrophotographic photoreceptor was measured in the same manner as in Example 1.

The results are as follows.

Charged potential +800 V -800 Vff/dt
6 & - Effects of the Invention As is clear from the comparison of the above Examples and Comparative Examples, the diphenyldicyanoethylene derivative represented by the above general formula (I>) used in the present invention is conventionally known to be relatively excellent. It exhibits an electron transport property equal to or higher than that of TNF, and therefore, an electrophotographic photoreceptor for positive charging using this material as an electron transport agent in a charge transport layer exhibits excellent electrophotographic properties.

Claims (1)

[Claims] (1) An electrophotographic photoreceptor having a photosensitive layer consisting of a charge generation layer and a charge transport layer on a conductive support, wherein the charge transport layer contains a diphenyldicyanoethylene derivative represented by the following general formula (I). An electrophotographic photoreceptor characterized by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, R_1 represents a hydrogen atom, a nitro group, or an alkoxycarbonyl group, and R_2 represents an alkyl group, an alkoxy group, a nitro group, a cyano group, or an alkoxycarbonyl group. , R_3 is a hydrogen atom, an alkoxycarbonyl group,
Represents a halogen atom or a nitro group, R_4 is a hydrogen atom, an alkyl group, a cyano group, a nitro group, a halogen atom,
It represents an alkoxycarbonyl group, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted 4-phenylphenyl group. )