JPH0235461A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To reduce residual potential of a photosensitive body and to enhance sensitivity and potential stability at the time of repeated uses by using a specified pigment as an electric charge generating material. CONSTITUTION:The photosensitive layer formed on a conductive substrate contains at least one kind of the tetraazaporphyrin derivatives represented by formula I and the tetraazaporphyrin metal complex salt derivatives represented by formula II. In formulae I and II, X is H, D, or the like; each of R1 and R2 is H, alkyl, or the like; M is a metal except Si and alkali metals; Y is halogen, hydroxy, or the like; and n is 0, 1, or 2. These pigments can be formed by condensing 4,5-dicyanophenanthrene with a metal (halide), or reacting phenanthrene-4,5-dicarboxylic acid (anhydride) with urea, and the pigment of formula III can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor containing a tetraazaporphyrin derivative having a specific structure and a tetraazaporphyrin metal complex salt.

[Prior Art J Inorganic photoconductors such as selenium, cadmium sulfide, and zinc oxide are known as photoconductors used in electrophotographic processes. However, compared to these inorganic photoconductors, electrophotographic photoreceptors using organic photoconductors have the advantage of being able to form films by coating, being extremely productive, and being able to provide inexpensive photoreceptors. In addition, it has the advantage of being able to freely control color sensitivity by selecting the sensitizers used, such as dyes and pigments, and has been extensively studied so far.

Phthalocyanine pigments are known for being stable against heat and light and exhibiting a deep blue color, and have recently attracted attention as organic materials that can be put to practical use not only as dyes but also as electronic materials and catalysts.

In the field of electrophotographic photoreceptors, numerous studies have been conducted, including US Pat. No. 3,816,118, which proposed the use of phthalocyanine pigments. Documents related to high-sensitivity phthalocyanine used in electrophotographic photoreceptors include ``Unexamined Japanese Patent Publication No. 5, which uses vanadyl phthalocyanine.''
7-146255, JP 62-119547 using dihalogenostinphthalocyanine, JP 59-49544 using titanyloxyphthalocyanine
No. 63-565, which also uses chloroindium chlorophthalocyanine as a phthalocyanine derivative.
Publication No. 64 and JP-A-63-5 using naphthalocyanine
There are publications such as No. 5556.

[Problem that the invention seeks to solve]

However, photoreceptors using conventional phthalocyanine pigments generally have a high residual potential, and are not always satisfactory in terms of potential stability and sensitivity during repeated use.
However, only a few materials have been put into practical use.

Therefore, an object of the present invention is to improve these drawbacks and provide a photoreceptor that can be put to practical use.

[Means for solving problems]

As a result of studies, the present inventors found that a tetraazaporphyrin derivative or a tetraazaporphyrin metal complex salt derivative with a specific structure solves the above-mentioned problems and exhibits excellent electrophotographic properties, and the present invention has been made based on this finding. It's arrived.

That is, the present invention provides an electrophotographic photoreceptor having a photosensitive layer on a conductive support, in which the photosensitive layer has the general formula (I) (wherein, represents an atom, R1 and R2 are a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, an alkoxy group,
It represents a halogen atom or a nitro group, and R1 and R2 may be the same or different. ) A tetraazaporphyrin derivative represented by the general formula (U) (wherein M represents a silicon atom and a metal atom other than an alkali metal, and Y represents a halogen atom.

Indicates a hydroxyl group, an alkoxy group, or an oxygen atom.

Further, n is an integer of o, l or 2. R1°R2 and n have the same meanings as R, and R2 in general formula (I). ) This is an electrophotographic photoreceptor characterized by containing at least one member selected from the group consisting of tetraazaporphyrin metal complex salt derivatives shown in the following.

In the above general formula, the alkali metal atom represents lithium, sodium, potassium, etc. Halogen atoms include chlorine, bromine, and fluorine.

Represents iodine, etc. As an alkoxy group, methyl,
Represents ethyl, propyl, etc. Examples of the aralkyl group include benzyl, phenethyl, naphthylmethyl, and the like. Examples of the aryl group include phenyl, naphthyl, pyrenyl, and the like. Examples of the alkoxy group include methoxy, ethoxy, and phenoxy.

Furthermore, these groups are halogen atoms and nitro groups.

It may have a substituent such as a cyano group or a hydroxyl group.

Further, M represents a silicon atom and a metal atom other than an alkali metal, specifically, beryllium, magnesium,
Calcium, strontium, barium, aluminum, silicon, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, yttrium, zirconium, niobium, technetium, ruthenium, rhodium, palladium, silver, cadmium, indium, tin, antimony,
Tellurium, barium, hafnium, tantalum, rhenium,
Osmium, iridium, platinum, gold, mercury, thallium,
A type selected from lead, bismuth, polonium, lanthanum, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and uranium.

A general method for producing the tetraazaporphyrin derivatives and tetraazaporphyrin metal complex salt derivatives of general formulas (I) and (II) used in the present invention will be described. The optimal synthesis method differs depending on the type of M, but in general, 4.
It can be synthesized from 5-dicyanophenanthrene (m) and a metal or metal halide.

)′ (m) (rV) (V
) The condensation reaction may be carried out either wet using an organic solvent or dry using no organic solvent. The organic solvent used in the wet condensation reaction can be arbitrarily selected, and may include α-chloronaphthalene, β-chloronaphthalene, α-bromonaphthalene, β-
Naphthalenes such as bromonaphthalene, α-methylnaphthalene, α-methoxynaphthalene, diphenyl ether,
3. Diphenyl ethers such as 3'-dimethyl diphenyl ether and 4.4'-dichlorodiphenyl ether;
Diphenylmethanes such as diphenylmethane, 4.4'-dimethyldiphenylmethane, 3.3'-dichlorodiphenylmethane, or benzene, toluene, xylene, monochlorobenzene1. Benzene derivatives such as dichlorobenzene, or ethanol, l-propanol,
It is possible to use alcohols such as 2-propatool.

Furthermore, in addition to terdiscyanophenanthrene (m), a method of forming a lithium complex and then converting it into another metal can be adopted.

The resulting pigment is treated with hot water and, if necessary, acid treatment,
Alkali treatment, solvent treatment, dry silling treatment, wet silling treatment.

For solvent treatment and wet silling treatment, organic solvents such as benzene, chlorobenzene, dichlorobenzene, acetone, methyl ethyl ketone, cyclohexanone, N,N-dimethylformamide, tetrahydrofuran, dioxane, quinoline, α-chloronaphthalene, and N-methylpyrrolidone are used alone. Alternatively, two or more types can be used in combination.

These treatments have the effect of changing the particle size and crystallinity of the pigment, and are also useful for improving purity.

Typical examples of the tetraazaporphyrin derivatives and tetraazaporphyrin metal complex derivatives of the present invention are listed below.

Note that some compounds have isomers. for example,
Compound (3) is a mixture of four isomers, of which only the structural formula is shown. These isomers may be used separately or as a mixture.

O2 NO2 OCH3 OCH3 N(J2 A coating containing a pigment represented by the above general formula (1) or (n) exhibits photoconductivity, and therefore can be used in a photosensitive layer of an electrophotographic photoreceptor.

That is, in the present invention, general formula (1),
An electrophotographic photoreceptor can be constructed by forming a film using the pigment represented by (rI) by vacuum evaporation, or by dispersing the pigment in a suitable binder to form a film.

In a preferred embodiment of the present invention, the above-mentioned film exhibiting photoconductivity may be applied as a charge generation layer in an electrophotographic photoreceptor in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer. can.

In order to obtain sufficient absorbance, the charge generation layer contains as much of the above-mentioned photoconductive compound as possible, and in order to shorten the range of the generated charge carriers, a thin film layer, for example 5 μm or less, is used. , preferably a thin film layer having a thickness of 0.01 to 1 μm.

As mentioned above, the charge generation layer can be formed, for example, by dispersing the pigment represented by the general formula (1) or (n) in a suitable binder and coating it on the support, or by vacuum deposition. It can be obtained by forming a vapor-deposited film using an apparatus. The binder used in forming the charge generating layer by coating can be selected from a wide variety of insulating resins and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene. Preferably, polyvinyl butyral, polyarylate, polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide resin, polyamide, polyvinylpyridine, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol, polyvinylpyrrolidone, etc. Examples include insulating resins. The resin contained in the charge generation layer is suitably 80% by weight or less, preferably 40% by weight or less.

The solvent that dissolves these resins varies depending on the type of resin, and is preferably selected from those that do not dissolve the underlying charge transport layer or subbing layer. Specific organic solvents include alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone, methyl ethyl ketone, cyclohexanone, and 2-methoxy-2-methyl-4-pentanone, N,N-dimethylformamide, N,
Amides such as N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, methylene chloride, dichloroethylene, and tetrachloride. Carbon, aliphatic halogenated hydrocarbons such as trichloroethylene, or aromatics such as benzene, toluene, xylene, ligroin, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating is done by dip coating method, spray coating method,
This can be done using a coating method such as a Meyer bar coating method. For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying at 30℃~2
It can be carried out at a temperature of 00° C. for a time ranging from 5 minutes to 2 hours, either stationary or under ventilation.

Further, the photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a known sensitizer. As a sensitizer, chloranil, quinones such as phenanthrenequinone, or ketones,
Examples include acid anhydrides, aldehydes, diano compounds, phthalide compounds, cyanine dyes, thiazine dyes, and quinone dyes.

Furthermore, the photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a well-known plasticizer in order to improve film formability, flexibility, and mechanical strength. As a plasticizer, phthalate ester,
Examples include aromatic compounds such as phosphoric acid esters and methylnaphthalene.

The charge transport layer may be located above the charge generation layer when viewed from the conductive support (or may be located between the conductive support and the charge generation layer).

Examples of the charge transport substance include fluorenone compounds such as 2,4,5,7-tetranitro-9-fluorenone, 2,4,7-dolinitro-9-dicyanomethylenefluorenone, and N-methyl-N-phenylhydrazino-3-methylidene. Carbazole compounds such as -9-ethylcarbazole, NlN-diphenylhydrazino-3-methylidene-9-ethylcarbazole, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, p-diethylaminobenzaldehyde-N-α-naphthyl-N −
Hydrazone compounds such as phenylhydrazone, 1-[
Pyridyl (2)) -3-(α-Methyl-p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-phenyl-3-(p-diethylaminostyryl)-4-methyl-5-(p pyrazoline compounds such as -diethylaminophenyl)pyrazoline, N-
Ethyl-3(α-phenylstyryl)carbazole, 9
-p-Dibenzylaminobenzylidene-9H-fluorenone, 5-p-ditolylaminobenzylidene-5H-dibenzo[a,d) Styryl compounds such as cycloheptene, 2-(p-diethylaminostyryl)-6-dinithylamino Benzoxazole, 2-(p-diethylaminophenyl)-4-(p-dimethylaminophenyl)-
Oxazole compounds such as 5-(2-chlorophenyl)oxazole, 2-(p-diethylaminostyryl)
-thiazole compounds such as 6-dinithylaminobenzothiazole, triarylmethane compounds such as bis(4-diethylamino-2-methylphenyl)-phenylmethane, 1,1-bis(4-N,N-diethylamino-
Examples include polyarylalkane compounds such as 2-methylphenyl)hebutane and 111.2.2-tetrakis(4-N,N-dimethylamino-2-methylphenyl)ethane.

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 substances can be used alone or in combination of two or more.

When the charge transport material does not have film-forming properties, a film can be formed by selecting an appropriate binder.

Since the charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary. Generally it is 5 to 40 μm, but the preferred range is 15 to 30 μm.
It is μm.

As the conductive support, aluminum, aluminum alloy, stainless steel, or conductively treated plastic or paper can be used, and a resin layer in which conductive particles are dispersed therein can also be used. Its shape may be any one such as a cylinder, film, or sheet.

An undercoat layer having barrier and adhesive functions can also be provided between the conductive support and the photosensitive layer. The thickness of the undercoat layer is 5 μm or less, preferably 0.1 to 3 μm.

In another specific example of the present invention, organic compounds such as the aforementioned carbazole compounds, hydrazone compounds, pyrazoline compounds, styryl compounds, oxazole compounds, thiazole compounds, triarylmethane compounds, polyarylalkane compounds, etc. The photosensitive film may contain a pigment of the general formula (I) or (n) as a sensitizer for a photoconductive substance or an inorganic photoconductive substance such as zinc oxide or selenium. This photosensitive film is formed by coating these photoconductive substances with the above-mentioned tetraazaporphyrin derivatives and tetraazaporphyrin metal complex salt derivatives of general formulas (I) and (TI) together with a binder.

Further, as another specific example of the present invention, the above-mentioned general formula (1)
Alternatively, an electrophotographic photoreceptor may be mentioned in which the pigment (rI) is contained in the same layer with a charge transport substance. In this case, in addition to the above-mentioned charge transport substance, a charge transfer complex compound consisting of poly-N-vinylcarbazole and trinitrofluorenone can be used. The electrophotographic photoreceptor of this example can be prepared by dispersing the pigment of general formula (I) or (n) and the charge transfer complex in a solution of polyester dissolved in tetrahydrofuran, and then forming a film thereon.

The pigment used in any of the photoreceptors contains at least one type of pigment selected from general formula (1) or (II), and its crystal form may be amorphous or crystalline. In addition, if necessary, pigments of general formula (I) or (II) may be used in combination to increase the sensitivity of the photoreceptor or to obtain a panchromatic photoreceptor.
It is also possible to use a combination of two or more types of pigments represented by or in combination with a charge generating substance selected from known dyes and pigments.

The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines, but also for laser printers, CRT printers, L
It can also be widely used in electrophotographic applications such as ED printers, liquid crystal printers, and laser engraving.

[Synthesis example]

Synthesis of copper-tetra-4,5-phenanthridinoporphyrazine Urea 1.30 (130 parts), ammonium molybdate 0
051 g (5 parts) are heated to 130-140 DEG C. in 40 g of alpha-chloronaphthalene. To this, 1.00 g (100 parts) of anhydrous phenanthrene-4,5-dicarboxylic acid
, 0.051 g (5 parts) of ammonium molybdate and 0.20 g (20 parts) of anhydrous copper chloride are added in portions.

The temperature was further raised and the mixture was heated and stirred at 150 to 160°C for 1 hour.

After the reaction was completed, the obtained blue solid was pulverized, washed with ethanol, hot water, 5% aqueous sodium hydroxide solution, 5% aqueous hydrochloric acid solution, and water in this order, and dried.

Yield 0.8g (yield 21.7%) 〔Example〕 The present invention will be explained below with reference to Examples.

Example 1 A 0.1 μm subbing layer made of vinyl chloride-maleic anhydride-vinyl acetate copolymer resin was provided on a aluminum plate.

Next, 5 g of the above-mentioned exemplary pigment (No. 1) was added to 95 mj of cyclohexanone! The mixture was added to a solution in which 2 g of butyral resin (degree of butyralization 63 mol %, number average molecular weight 20,000) was dissolved, 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 0.5 μm, and dried to form a charge generation layer. Next, the photoreceptor of Example 1 was manufactured by coating the structure with a Mayer bar so that the film thickness after drying was 20 μm and drying to form a charge transport layer. Photoreceptors corresponding to Examples 2 to 14 were produced in exactly the same manner using other exemplary pigments shown in Table 1 in place of pigment (No. 1).

The electrophotographic photoreceptor manufactured in this manner was tested using an electrostatic copying paper testing device MODE ISP-4 manufactured by Kawaguchi Denki ■.
After corona charging at -5.5KV using static method using 28 and holding it for 1 second in a dark place, the illuminance was 101! It was exposed to UV light and its charging characteristics were examined. The charging characteristics include surface potential (VO
) and the exposure amount (E%) required to attenuate the potential to B after dark decaying for 1 second was measured. Furthermore, the surface potential vR after 30 seconds of exposure was also measured. The results are shown in Table 1.

5 g of hydrazone compound and 5 g of polymethyl methacrylate resin (number average molecular weight 100,000) were dissolved in 70 m4 of chlorobenzene and dried on the charge generation layer. Dissolved in
Then, it was dropped into 200 rrl of pure water to regenerate the pigment. The mixture was filtered, washed successively with warm water, a 5% aqueous sodium carbonate solution, and warm water, and dried under reduced pressure to obtain a blue pigment with metallic luster. The pigment obtained here was used in place of the pigment (No. 1) in Example 1, except that the corresponding photoreceptors were produced in the same manner as in Example 1, and evaluated in the same manner as in Examples 1 to 15. The results are shown in Table 2.

Table 2 Examples 17 to 19 100 mj' of glass beads with a particle size of 0.3 mm were placed in a 300 mf beaker, and 3 g of pigment (NoJ) and α-
Chloronaphthalene 150m1! was added and heated and stirred at 170°C for 5 hours. After cooling to room temperature, the glass beads were separated, thoroughly washed with ethanol and then warm water, and dried. The pigment thus obtained was used as the pigment of Example 1 (No.
A photoreceptor was manufactured in exactly the same manner as in Example 1, except that . In addition, evaluations were made in the same manner by changing the solvent used for the treatment, the treatment temperature, and the treatment time as shown in Table 3. These results are summarized in Table 3.

A solution prepared by dissolving 5 g of the benzylidene compound shown in Table 3 and 5 g of bisphenol Z type polycarbonate resin (viscosity average molecular weight 30,000) in 32.5 g of monochlorobenzene was applied onto the charge generation layer so that the film thickness after drying was 20 μm. , to form a charge transport layer. The charging characteristics of the photoreceptor thus produced were measured in the same manner as in Example 1. The results are shown in Table 4.

Table 4 Example 20 Pigments (No, L) were deposited on an aluminum substrate to a film thickness of 100 m.
A charge generation layer was formed by vacuum evaporation to give a ratio of g/a.

Next, the photoreceptor used in Example 1.4.6.8 was used to measure changes in bright area potential and dark area potential during repeated use. The method is to attach the photoreceptor to the cylinder of an electrophotographic copying machine equipped with a -5.6KV corona charger, exposure optical system, developer, transfer charger, static elimination exposure optical system, and cleaner. The structure is such that an image is obtained on the transfer paper as the transfer unit is driven. Using this copying machine, the initial bright area potential (VL) and dark area potential (VD) were set to 100% each.
V, set around -600V, and measured the bright area potential (VL) and dark area potential (VD) after using it 5000 times.

did. The results are shown in Table 5.

Examples 1 to 3 except that the phthalocyanine pigment shown in
The charging characteristics were evaluated in exactly the same manner as No. 15. These results and the corresponding measurement results for the pigments of the present invention are shown in Table 6.

From the results in Table 5, it can be seen that the potential stability during durable use is good.

Comparative Examples 1 to 3 The following structural formula No. 6 was used instead of the pigment (No. 15) of Example 1.
From the results in the table, it can be seen that the electrophotographic photoreceptor using the pigment of the present invention has high sensitivity and is excellent in that it has a low residual potential.

〔Effect of the invention〕

As described above, the tetraazaporphyrin derivative and the tetraazaporphyrin metal complex salt derivative of the present invention have extremely high sensitivity and can form an electrophotographic photoreceptor with excellent potential stability during repeated use.

Claims (1)

[Claims] (1) In an electrophotographic photoreceptor having a photosensitive layer on a conductive support, the photosensitive layer has the general formula (I) ▲ Numerical formula, chemical formula, table, etc. ▼ (However, in the formula, X is a hydrogen atom, Represents a hydrogen atom or an alkali metal atom, R_1 and R_2 represent a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, an alkoxy group, a halogen atom, a nitro group, R_1 and R_
2 may be the same or different. ), and the general formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, in the formula, M represents a silicon atom and a metal atom other than an alkali metal, Y represents a halogen atom, Represents a hydroxyl group, an alkoxy group, or an oxygen atom. Also, n is 0, 1 or 2
is an integer. R_1, R_2 and n have the general formula ( I
) has the same meaning as R_1 and R_2. ) An electrophotographic photoreceptor comprising at least one member selected from the group consisting of tetraazaporphyrin metal complex salt derivatives represented by: