JPH02226159A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a high-sensitivity characteristic and the stable potential characteristic in repetitive use by providing a photosensitive layer contg. a specific compd. on a conductive base. CONSTITUTION:This photosensitive body has the photosensitive layer contg. the compd. expressed by formula I on the conductive base. In the formula I, X denotes an aryl group which may have a substituent, arylene group, heterocyclic group, diaryl amino group or triaryl amino group; Y denotes -CH2-, -CH2- CH2-, -CH=CH- or single bond; n denotes 0 or 1 integer; m denotes 1 to 3 integer; R1 and R2 denote an alkyl group, aryl group, aralkyl group, cyano group, nitro group or halogen atom; R1 and R2 may be the same or different; R3 denotes an alkyl group, aryl group or aralkyl group which may have a substituent. The photosensitive body having the high sensitivity and the characteristics excellent in the potential stability at the time of repetitive use is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor containing a specific compound.

[Prior Art] Electrophotographic photoreceptors using inorganic photoconductors such as selenium, cadmium sulfide, and zinc oxide as photosensitive components have been widely known.

On the other hand, since the discovery that certain organic compounds exhibit photoconductivity, a number of organic photoconductors have been developed. Carbazole compounds, anthracene compounds, pyrazoline compounds,
Low-molecular organic photoconductors such as oxadiazole compounds, hydrazone compounds, polyarylalkane compounds, phthalocyanine pigments, azo pigments, polycyclic pigments, perylene pigments, indigo dyes, thioindigo dyes, or squaric acid. Organic pigments and dyes such as methine dyes are known.

In particular, organic pigments and dyes with photoconductivity are easier to synthesize than inorganic materials, and the variety of compounds that exhibit photoconductivity in an appropriate wavelength range has expanded. Organic pigments and dyes have been proposed.

For example, U.S. Pat. No. 4,123,270, 4,247
Specification No. 614, Specification No. 4251613, No. 4
Specification No. 251614, Specification No. 4256821,
Specification No. 4260672, Specification No. 4268596, Specification No. 4278747, Specification No. 429362
Electrophotographic photoreceptors using an azo pigment exhibiting photoconductivity as a charge-generating substance in a photosensitive layer functionally separated into a charge-generating layer and a charge-transporting layer are known, as disclosed in Japanese Patent Application No. 8.

An electrophotographic photoreceptor using such an organic photoconductor can be produced by coating by appropriately selecting a binder, so it is possible to provide an electrophotographic photoreceptor with extremely high productivity and low cost. This electrophotographic photoreceptor has the advantage of being able to freely control the sensitive wavelength range by selection, and improvements have been made in terms of sensitivity and durability, and many of them have come into practical use.

In particular, it has recently been known that an electrophotographic photoreceptor using a dye such as pyrrolovirol disclosed in JP-A-61-162555 exhibits photoconductivity due to intramolecular charge transfer.

[Problems to be Solved by the Invention] An object of the present invention is to provide a novel photoconductive material;
To provide an inexpensive electrophotographic photoreceptor having practical high-sensitivity characteristics and stable potential characteristics during repeated use, and to provide a novel charge-transfer type compound having an electron-donating moiety and an electron-withdrawing moiety in the molecule. There is a particular thing.

[Means for Solving the Problems, Effects] The present invention comprises an electrophotographic photoreceptor characterized by having a layer containing a compound represented by the following general formula (1).

In the formula, X represents an aryl group, an arylene group, a heterocyclic group, a diarylamino group, or a triarylamino group which may have a substituent, and Y represents 0-CHzJ:H-, -0H-OH- or Represents a single bond, n is O or an integer of 1, m is an integer of 1.2 or 3, and R1 and R2 are an alkyl group that may have a substituent, an aryl group, an aralkyl group, a cyano group, a nitro represents a group or a halogen atom, and R1 and R2 may be the same or different.

R3 represents an alkyl group, an aryl group, or an aralkyl group which may have a substituent.

Substituents for X include groups selected from alkyl groups, aralkyl groups, and aryl groups, and substituents for R1, R2, and R3 include groups selected from alkyl groups, halogen atoms, cyano groups, nitro groups, and the like.

In the above expressions, alkyl groups include methyl, ethylpropyl, and butyl, aralkyl groups include benzyl, phenethyl, and naphthylmethyl, and aryl groups include phenyl, diphenylnaphthyl, anthryl, pyrenyl, perylene, and arylene. Groups include phenylene, naphthylene, birenylene, perylenenylene, etc.
Examples of heterocyclic groups include pyridyl, thienyl, furyl, thiazolyl, carbazolyl, dipenzofuryl, benzimidazolyl, and benzothiazolyl; diarylamino groups include diphenylamino, dinaphthylamino, and dibenzylamino; and triarylamino groups include groups such as diphenylamino, dinaphthylamino, and dibenzylamino. Groups such as triphenylaminotrinaphthylamino and tribenzylamino, and examples of the halogen atom include chlorine atom, fluorine atom, bromine atom, and iodine atom.

Typical specific compounds of the compound represented by general formula (1) are listed below.

Compound Example (1) Compound Example Compound Example Compound Example Compound Example Compound Example (9) Compound Example (10) Compound Example (11) Compound Example (12) Compound Example Compound Example Compound Example Compound Example (13) Compound Example (1 Compound Example (15) Compound Example (1 Compound Example (1 Compound Example (19) 0M Compound Example (23) OL Compound Example (24) Compound Example (25) Compound Example (20) Compound Example (21) Compound Example (22) NOS Compound Example (26) Compound Example (27) Compound Example (28) Compound Example (29) OxN Compound Example (30) The compound represented by the general formula (1) has m=2゜n=0, Y
= In the case of NOCM, it can be synthesized by a conventional method as shown below, for example.

Synthesis Example (Synthesis of Compound Example (1)) 2 g of 4'-diformyl-N-methyldiphenylamine and 1.5 g of 9-dicyanomethylene-10-diethylphosphonylanthracene were added to 150 m of tetrahydrofuran.
0.13 g of NaH was added. After heating and stirring at 40° C. for 2.5 hours, one reaction solution was filtered.

The obtained reddish-purple crystals were dispersed and washed four times with 150 ml of methanol for 30 minutes each, and then dried in vacuum. Yield 2g Elemental analysis experimental value (%) Theoretical value (%) C84,4684,48 H4,604,57 N 10.97 10.95 The film containing the compound represented by the above general formula (1) is photoconductive Therefore, it can be used in the photosensitive layer of the electrophotographic photoreceptor.

The electrophotographic photoreceptor of the present invention has the general formula (
It has a photosensitive layer containing the compound shown in 1).

The form of the photosensitive layer may be any known form, but a photosensitive layer containing the compound represented by general formula (1) is used as a charge generation layer, and a charge transport layer containing a charge transport substance is laminated thereon. A functionally separated type photosensitive layer is particularly preferred.

The charge generation layer can be formed by coating a coating solution in which the compound represented by formula (1) is dispersed together with a binder resin in an appropriate solvent on a conductive support by a known method, and the resulting film is The thickness of the thin film layer is preferably 5 #Lm or less, preferably 0.01 to 1 pm.

The binder resin used in this case is selected from a wide range of insulating resins or organic photoconductive polymers, including polyvinyl butyral, polyvinylbenzal, polyarylate, polycarbonate, polyester, phenoxy resin, cellulose resin, acrylic resin, polyurethane. etc., and the amount used is preferably 80% in terms of content in the charge generation layer.
It is not more than 40% by weight, preferably not more than 40% by weight.

The solvent used is preferably selected from those that dissolve the resin described above but do not dissolve the charge transport layer or undercoat layer described later.

Specifically, ethers such as tetrahydrofuran and 1,4-dioxane, and cyclohexanone.

Ketones such as methyl ethyl ketone, amides such as N,N-dimethylformamide, esters such as methyl acetate and ethyl acetate, toluene, and xylene.

Examples include aromatics such as chlorobenzene, alcohols such as methanol, ethanol, and 2-propanol, and aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichlorethylene.

The charge transport layer is laminated above or below the charge generation layer, and has the function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting them.

The charge transport layer is formed by dissolving a charge transport material in a solvent together with a suitable binder resin as necessary and applying the film, and the film thickness is generally 5 to 40 pm, but 8.
~30 gm is preferred.

Charge transporting substances include electron transporting substances and hole transporting substances. Examples of electron transporting substances include 2゜4,7-trinitrofluorenone, 2,4,5゜7-tetranitrofluorenone, chloranil, and tetranitrofluorenone. Examples include electron-withdrawing substances such as cyanoquinodimethane, and polymerization of these electron-withdrawing substances.

Hole-transporting substances include polycyclic aromatic compounds such as pyrene and anthracene, carbazole-based, indole-based, imidazole-based, oxazole-based, thiazole-based, oxadiazole-based, pyrazole-based pyrazoline-based, thiadiazole-based, triazole-based compounds, etc. heterocyclic compound, p-
Hydrazone-based compounds such as diethylaminobenzaldehyde-N,N-diphenylhydrazone, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, α-phenyl-4°-N,N-diphenylaminostilbene, 5-[ 4-(di-p-tolylamino)benzylidene] -5H-dibenzo[a, d] A styryl compound such as cycloheptene, a benzidine compound, a triarylmethane compound, triphenylamine, or a group consisting of these compounds. Examples include polymers having it in the chain or side chain (eg, poly-N-vinylcarbazole, polyvinylanthracene, etc.).

In addition to these organic charge transport materials, inorganic materials such as selenium, selenium-tellurium, amorphous silicon, and cadmium sulfide can also be used.

Further, these charge transport materials can be used alone or in combination of two or more.

When the charge transport material does not have film-forming properties, an appropriate binder can be used, specifically, acrylic resin, polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, polyacrylamide, polyamide, chlorine. Insulating resin such as rubber or poly-N-vinylcarbazole,
Examples include organic photoconductive polymers such as polyvinylanthracene.

Examples of the conductive support on which the photosensitive layer is formed include aluminum, aluminum alloy, copper, zinc stainless steel, titanium, nickel, indium, gold, and platinum. In addition, plastics (e.g. polyethylene,
Polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, etc.) or conductive particles (e.g. carbon black, silver particles, etc.) are coated on a plastic or metal substrate together with a suitable binder resin, or conductive particles are coated on a plastic or metal substrate. A support such as paper impregnated can be used.

A subbing layer having barrier and adhesive functions can also be provided between the conductive support and the photosensitive layer.

The subbing layer can be formed of casein, polyvinyl alcohol, nitrocellulose, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, aluminum oxide, or the like.

The thickness of the subbing layer is 5 gm or less, preferably 0.5 to 3 m.
is appropriate.

Another specific example of the present invention is an electrophotographic photoreceptor containing the compound represented by general formula (1) and a charge transport material in the same layer. At this time, a charge transfer complex consisting of poly-N-vinylcarbazole and trinitrofluorenone can also be used as the charge transport substance. The electrophotographic photoreceptor of this example can be formed by coating and drying a solution in which a compound represented by general formula (1) and a charge transporting substance are dispersed in a suitable resin solution.

The general formula used in any electrophotographic photoreceptor (
It contains the compound shown in 1), and its crystal form may be amorphous or crystalline.

It is also possible to use a combination of two or more types of compounds represented by the general formula (1), or to use them in combination with a known charge-generating substance.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in a wide range of electrophotographic applications such as laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making.

[Example] Examples 1 to 12 5 g of methoxymethylated nylon (average molecular weight 32,000) and 10 g of alcohol-soluble copolymerized nylon (average molecular weight 29,000) were placed on an aluminum support in 95 g of methanol.
A solution dissolved in was applied with a Mayer bar to form an undercoat layer having a thickness of 1 gm after drying.

Next, 5 g of compound example (1) was added to 95 m of cyclohexanone.
2 g of butyral resin (degree of butyralization 63 mol%) for M
was added to the dissolved solution and dispersed in a sand mill for 20 hours.

This dispersion was applied onto the previously formed undercoat layer using a Mayer bar so that the film thickness after drying was 0.2 pm, and dried to form a charge generation layer.

5g of hydrazone compound and polymethyl methacrylate (
5 g (number average molecular weight: 100,000) was dissolved in 40 mu of toluene, and this was applied onto the charge generation layer using a Mayer bar and dried.
A charge transport layer having a thickness of 201 Lm was formed to produce an electrophotographic photoreceptor of Example 1.

Using a compound of another compound example in place of compound example (1),
Photoreceptors corresponding to Examples 2 to 12 were prepared in exactly the same manner.

The electrophotographic photoreceptor thus prepared was tested using an electrostatic copying paper tester (Model 5F-428, manufactured by Kawaguchi Denki ■).
The sample was corona-charged at -5 KV using a microcomputer, held in a dark place for 1 second, and then exposed to light at an illuminance of 10 lux to evaluate charging characteristics.

The charging characteristics include the surface potential (Vo) and the amount of exposure required to attenuate the surface potential by half (El/2) after being left in the dark.
) was measured. Show the results.

1 (1) 675 2.
52 (3) 680 3
．． 83 (4) 695 2
．． 811, (21) Comparative Examples 1 and 2 Comparative Examples 1 and 2 were carried out in exactly the same manner as in Example 1, except that the compound of Compound Example (1) used in Example 1 was used in place of the compound represented by the following structural formula. An electrophotographic photoreceptor corresponding to the above was prepared, and its charging characteristics were evaluated in the same manner. Show the results.

(Comparative example 1) El/2: 5.41uxs 5ec (Comparative example 2) vo knee 620V El/2: 5. 31ux @ sec
From the Examples and the Comparative Examples above, it can be seen that the electrophotographic photoreceptors of the present invention all have sufficient charging ability and excellent sensitivity.

Examples 13 to 15 Using the electrophotographic photoreceptors prepared in Examples 1.4 and 12, fluctuations in bright area potential and dark area potential during repeated use were measured.

As a method, the photoreceptor was attached to the cylinder of an electrophotographic copying machine equipped with a -6.5 KV corona charger, an exposure optical system, a developing device, a transfer charger, static elimination exposure optics, and a cleaner. In this welfare printing, as the cylinder is driven, an image is obtained on the transfer paper. The amount of variation in dark area potential (ΔVo) and the amount of variation in bright area potential (ΔVL) were measured after repeated use 5,000 times.

Show the results.

Note that a negative sign in the amount of change in potential represents a decrease in potential, and a positive sign represents an increase in potential.

13 1 -13 +
1OL4 4 -10
+715 12 ~10
+6 Comparative Examples 3 and 4 Regarding the photoreceptors used in Comparative Examples 1 and 2, Example 13
Potential fluctuations during repeated use were measured using the same method as above. Show the results.

3 1 -85
+804 2 -80
-h50 From the above results, it can be seen from Examples 13 to 15 and Comparative Examples 3.4 that the electrophotographic photoreceptor of the present invention has little potential fluctuation when used repeatedly for 1 m.

Example 16 A polyvinyl alcohol film having a thickness of 0.5 ILm was formed on the aluminum surface of an aluminum vapor-deposited polyethylene terephthalate film.

A dispersion of the compound of Compound Example (22) used in Example 12 was applied onto this using a Mayer bar and dried, resulting in a film thickness of 0.2
．． A charge generation layer of pm was formed.

Next, a solution prepared by dissolving 5 g of a styryl compound represented by the following structural formula and 5 g of polyarylate (condensation polymer of bisphenol A and terephthalic acid-isophthalic acid) in 40 mjl of tetrahydrofuran was coated on the charge generation layer and dried to obtain a film thickness of 20 mjl.
A charge transport layer of 1.0 m was formed.

The charging characteristics and durability characteristics of the electrophotographic photoreceptor thus prepared were measured in the same manner as in Examples 1 and 13. Show the results.

v(, knee 690V El/2: 1.61ux*sec ΔVo knee 15V ΔyL, +av Example 17 A photosensitive material in which the charge transport layer and charge generation layer of the electrophotographic photoreceptor prepared in Example 1O were coated and laminated in the reverse order. A body was prepared, and the charging characteristics were evaluated in the same manner as in Example 1.However, the charging polarity was set to 10.The results are shown below.

vo: +700V El/2: 3.21ux* seC Example 18 On the charge generation layer prepared in Example 9, 5 g of 2,4.7-dolinitro-9-fluorenone and poly-4,4'-dioxydiphenyl were added. A coating solution prepared by dissolving 5 g of -2.2-propane carbonate (molecular weight: 300,000) in 70 ml of chlorobenzene was applied to a dry film thickness of 151 Lm and dried to form a charge transport layer.

The charging characteristics of the electrophotographic photoreceptor thus prepared were measured in the same manner as in Example 1. However, the charging polarity was set to 10.

Show the results.

Vo: +680V El/2: 3.51ux*sec Example 19 2.4.7-1 5g of linitro-9-fluorenone and 5g of poly-N-vinylcarbazole (number average molecular weight: 300,000)
A charge transfer complex was prepared by dissolving the following in 70 ml of tetrahydrofuran.

This charge transfer complex and 1 g of the compound of the above compound example (19)
was added to a solution in which 5 g of polyester (trade name: Vylon, manufactured by Toyobo ■) was dissolved in 70 ml of tetrahydrofuran and dispersed.

This dispersion was applied onto the undercoat layer prepared in Example 1 and dried to form a photosensitive layer having a thickness of 16 ILm.

The electrophotographic photoreceptor thus produced was evaluated in the same manner as in Example 1. The results are shown in Table 6. However, the charging polarity was set to 10.

vo: +690V El/2: 2.9Jlux*sec [Effect of the invention]

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor characterized by having a layer containing a compound represented by the following general formula (1). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (1) In the formula, X represents an aryl group, arylene group, heterocyclic group, diarylamino group, or triarylamino group that may have a substituent, and Y represents There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Mathematical formulas, chemical formulas, tables, etc. There is ▼, -CH_
2-, -CH_2-CH_2-, -CH=CH- or a single bond, n is an integer of 0 or 1, m is an integer of 1, 2 or 3, and R_1 and R_2 have a substituent. R_1 and R_2 may be the same or different, R_3
represents an alkyl group, an aryl group, or an aralkyl group which may have a substituent.