JP2637485B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: FIELD OF THE INVENTION 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)

Inorganic photoconductors such as selenium, cadmium sulfide, and zinc oxide are known as photoconductors used in the electrophotographic process. However, compared to these inorganic photoconductors,
Electrophotographic photoreceptors using organic photoconductors have good film-forming properties,
It has the advantage that it can be produced by coating and that it can provide an inexpensive photoreceptor with extremely high productivity. Further, there is an advantage that color sensitivity can be freely controlled by selecting a sensitizer such as a dye or a pigment to be used, and wide studies have been made so far.

BACKGROUND ART Phthalocyanine pigments are known for exhibiting a deep blue color that is stable to heat and light, and have attracted attention in recent years not only as dyes but also as organic materials that can withstand practical use as electronic materials and catalysts. Numerous studies have been made in the field of electrophotographic photoreceptors, including US Pat. No. 3,816,118, which proposed the use of phthalocyanine pigments. References relating to high-sensitivity phthalocyanines used in electrophotographic photoreceptors include JP-A-57-146255 using vanadyl phthalocyanine, JP-A-62-119547 using dihalogenotin phthalocyanine, and titanyloxyphthalocyanine. JP-A-59-49544, JP-A-63-56564 using chloroindium chlorophthalocyanine as a phthalocyanine derivative, and JP-A-63-55556 using naphthalocyanine.

[Problems to be solved by the invention]

However, photoreceptors using conventional phthalocyanine pigments generally have high residual potentials, which are not always satisfactory in terms of potential stability and sensitivity upon repeated use, and very few materials have been put to practical use. Only. The object of the invention is therefore to remedy these disadvantages,
An object of the present invention is to provide a photosensitive member that can withstand practical use.

[Means for solving the problem]

The present inventors have studied and found that a tetraazaporphyrin derivative or a tetraazaporphyrin metal complex derivative having a specific structure solves the above-mentioned problems and realizes excellent electrophotographic properties. Reached.

That is, the present invention relates to an electrophotographic photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer has a general formula (I) (Where X represents a hydrogen atom, a deuterium atom or an alkali metal atom, and A may have a substituent Represents A) a tetraazaporphyrin derivative represented by the general formula (II) (Wherein, M represents a metal atom other than a silicon atom and an alkali metal, Y represents a halogen atom, a hydroxyl group, an alkoxy group, or an oxygen atom. Further, n is an integer of 0, 1 or 2, and A is An electrophotographic photoreceptor comprising at least one selected from the group consisting of tetraazaporphyrin metal complex salt derivatives represented by the following general formula (I):

In the above general formula, the alkali metal atom represents lithium, sodium, potassium or the like. The halogen atom represents chlorine, bromine, fluorine, iodine and the like. Examples of the alkoxy group include methoxy, ethoxy, butoxy and the like.

Also, in the general formula Examples of the substituent which may have an alkyl group such as methyl, ethyl and propyl; an alkoxy group such as methoxy, ethoxy and propoxy; a halogen atom such as chlorine, bromine, fluorine and iodine, and a nitro group. .

M represents a silicon atom or a metal atom other than an alkali metal, and 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,
It is a kind 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 derivative of the general formula (I) and the tetraazaporphyrin metal complex salt derivative of the general formula (II) used in the present invention will be described. M
Although the optimal synthesis method differs depending on the type of the compound, generally, the tetraazaporphyrin derivative (I) and the tetraazaporphyrin metal complex salt derivative (II) have the corresponding dicyano forms (III), (IV), (V) and (V). It can be synthesized from VI), (VII) and metal or metal halide.

The dicyano forms of (III), (IV), (V), (VI), and (VII) have the above-mentioned halogen atom as a substituent,
It may have an alkyl group, an alkoxy group or a nitro group.

The condensation reaction may be either a wet method using an organic solvent or a dry method using no organic solvent. The organic solvent used in the wet condensation reaction can be arbitrarily selected, and α-chloronaphthalene, β-chloronaphthalene, α-bromonaphthalene, β
-Bromonaphthalene, α-methylnaphthalene, naphthalenes such as α-methoxynaphthalene, diphenylether, diphenylethers such as 3,3′-dimethyldiphenylether, 4,4′-dichlorodiphenylether, diphenylmethane, 4,4'-dimethyldiphenylmethane,
Use of diphenylmethanes such as 3,3'-dichlorodiphenylmethane, benzene derivatives such as benzene, toluene, xylene, monochlorobenzene and dichlorobenzene, or alcohols such as ethanol, 1-propanol and 2-propanol Is possible.

Furthermore, the dicyano bodies (III), (IV), (V), (V
Instead of I) and (VII), the following dicarboxylic acids (VII
(I), (IX), (X), (XI), (XII) and urea, or acid anhydrides (XIII), (XIV), (XV), (XVI), (XV
II) and urea can also be used respectively. These dicarboxylic acids and acid anhydrides may have a halogen atom, an alkyl group, an alkoxy group or a nitro group as a substituent, similarly to the dicyano compound.

In addition, a method of converting a lithium complex into another metal can be employed.

The obtained pigment is subjected to a hot water treatment, and if necessary, an acid treatment, an alkali treatment, a solvent treatment, a dry shilling treatment, or a wet shilling treatment.

For solvent treatment and wet-shilling treatment, benzene, chlorobenzene, dichlorobenzene, acetone, methyl ethyl ketone, cyclohexanone, N, N-dimethylformamide, tetrahydrofuran, dioxane, quinoline, α-
Organic solvents such as chloronaphthalene and N-methylpyrrolidone can be used alone or in combination of two or more. These treatments have the effect of changing the particle size and crystallinity of the pigment, and at the same time, contribute to improving the purity.

Hereinafter, representative examples of the tetraazaporphyrin derivative and the tetraazaporphyrin metal complex derivative of the present invention will be described.

The structural formula of the raw material No. 1 has four pyridine nuclei. N is a counterclockwise direction. Examples are shown in the 1,8,15,22 positions, but they are not necessarily aligned in such a direction, and instead of the 1,8,15,22 positions, 4,11,18,2
It could be fifth. The same applies to pigment Nos. 2 to 60.

The coating containing the pigment represented by the above general formula (I) or (II) exhibits photoconductivity, and thus can be used for a photosensitive layer of an electrophotographic photoreceptor.

That is, in the present invention, a film of the pigment represented by the general formula (I) or (II) is formed on a conductive support by a vacuum evaporation method, or is dispersed and contained in an appropriate binder to form a film. An electrophotographic photosensitive member can be configured.

In a preferred embodiment of the present invention, the above-mentioned photoconductive film is applied as the charge generation layer in the electrophotographic photosensitive member in which the photosensitive layer of the electrophotographic photosensitive member is functionally separated into a charge generation layer and a charge transport layer. it can.

The charge generation layer contains as much of the aforementioned photoconductive compound as possible in order to obtain sufficient absorbance, and a thin film layer, for example, 5 μm or less, preferably in order to shorten the range of the generated charge carrier. Is preferably a thin film layer having a thin film of 0.01 to 1 μm.

The charge generation layer includes, for example, the general formula (I) as described above,
Alternatively, the pigment can be formed by dispersing the pigment represented by (II) in a suitable binder and applying it to a support, or can be obtained by forming a vapor deposition film with a vacuum vapor deposition device. The binder that can be used when forming the charge generation layer by coating can be selected from a wide range of insulating resins, and can be selected from 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, polyvinyl pyridine, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone and the like An insulating resin can be used. The amount of the resin contained in the charge generation layer is suitably 80% by weight or less, preferably 40% by weight or less.

The solvent for dissolving these resins differs depending on the type of the resin, and is preferably selected from those which do not dissolve the charge transport layer and the undercoat layer described below. Specific organic solvents include alcohols such as methanol, ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone, cyclohexanone, 2-methoxy-2-methyl-4-pentanone, N, N-dimethylformamide, N, N
Amides such as dimethylacetamide, sulfoxides such as dimethylsulfoxide, tetrahydrofuran,
Dioxane, ethers such as ethylene glycol monomethyl ether, methyl acetate, esters such as ethyl acetate, chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, aliphatic halogenated hydrocarbons such as trichloroethylene or benzene, toluene, Aromatic substances such as xylene, ligroin, monochlorobenzene, and cyclobenzene can be used.

The coating can be performed by using a coating method such as an immersion coating method, a spray coating method, and a Meyer bar coating method. Drying is preferably performed by touch drying at room temperature and then heating and drying. Heat drying is 30 ° C ~
It can be carried out at a temperature of 200 ° C. for a time ranging from 5 minutes to 2 hours, still or under blast.

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

Further, the photosensitive layer of the electrophotographic photoreceptor of the present invention has a film-forming property,
A well-known plasticizer may be contained in order to improve flexibility and mechanical strength. Examples of the plasticizer include phthalic acid esters, phosphoric acid esters, and aromatic compounds such as methylnaphthalene.

The charge transport layer may be located above the charge generation layer as viewed from the conductive support, or may be located between the conductive support and the charge generation layer.

As the charge transport material, 2,4,5,7-tetranitro-9
Fluorenone compounds such as fluorenone, 2,4,7-trinitro-9-dicyanomethylenefluorenone, N-
Methyl-N-phenylhydrazino-3-methylidene-9
-Ethylcarbazole, N, N-diphenylhydrazino-
Carbazole compounds such as 3-methylidene-9-ethylcarbazole, hydrazone compounds such as p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, p-diethylaminobenzaldehyde-N-α-naphthyl-N-phenylhydrazone; -[Pyridyl (2)]-3- (α-methyl-p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazolin, 1-phenyl-3- (p-diethylaminostyryl) -4-methyl-5 Pyrazoline compounds such as-(p-diethylaminophenyl) pyrazoline, N-ethyl-3 (α-phenylstyryl) carbazole, 9-p-
Dibenzylaminobenzylidene-9H-fluorenone, 5
-P-ditolylaminobenzylidene-5H-dibenzo [a,
b] styryl compounds such as cycloheptene, 2- (p
-Diethylaminostyryl) -6-diethylaminobenzoxazole, 2- (p-diethylaminophenyl)
Oisazole compounds such as -4- (p-dimethylaminophenyl) -5- (2-chlorophenyl) oxazole, thiazole compounds such as 2- (p-diethylaminostyryl) -6-diethylaminobenzothiazole,
Triarylmethane compounds such as bis (4-diethylamino-2-methylphenyl) -phenylmethane;
Polyarylalkane compounds such as -bis (4-N, N-diethylamino-2-methylphenyl) heptane and 1,1,2,2-tetrakis (4-N, N-dimethylamino-2-methylphenyl) ethane; No.

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

These charge transport materials can be used alone or in combination of two or more.

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

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

The conductive support is made of aluminum, aluminum alloy,
It is possible to use stainless steel or plastic or paper which has been subjected to a conductive treatment, and it is also possible to use those provided with a dispersed resin layer of conductive particles. The shape may be any of a cylinder, a film, a sheet and the like.

An undercoat layer having a barrier function and an adhesive function may 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, the carbazole compound, the hydrazone compound, the pyrazoline compound,
As a sensitizer for organic photoconductive substances such as styryl compounds, oxazole compounds, thiazole compounds, triarylmethane compounds, and polyarylalkane compounds, and inorganic photoconductive substances such as zinc oxide and selenium, the above-mentioned general formula A photosensitive film containing the pigment of (I) or (II) can be used. This photosensitive film is formed by applying the photoconductive substance and the tetraazaporphyrin derivative and the tetraazaporphyrin metal complex salt derivative represented by the above general formulas (I) and (II) together with a binder.

Another specific example of the present invention is an electrophotographic photoreceptor in which the above-described pigment of the general formula (I) or (II) is contained in the same layer together with the charge transporting substance.
In this case, a charge transfer complex compound comprising poly-N-vinylcarbazole and trinitrofluorenone can be used in addition to the above-described charge transport material. The electrophotographic photoreceptor of this example can be prepared by dispersing the above-described pigment of the general formula (I) or (II) and the charge transfer complex in a solution of polyester dissolved in tetrahydrofuran, and then forming a film.

The pigment used in any of the photoreceptors has the general formula (I)
Or it contains at least one kind of pigment selected from (II), and its crystalline form may be amorphous or crystalline. If necessary, a pigment represented by the general formula (I) or (II) may be used in combination with a pigment having a different light absorption to enhance the sensitivity of the photoreceptor or obtain a panchromatic photoreceptor. It is also possible to use a combination of two or more kinds or a combination with a charge generating substance selected from known dyes and pigments.

The electrophotographic photoreceptor of the present invention is used not only for an electrophotographic copying machine, but also for a laser printer, a CRT printer, and an LED.
It can be widely used in electrophotographic applications such as printers, liquid crystal printers, and laser plate making.

(Synthesis example)

Synthesis of Pigment No.16 6.39 (106.4 mmol) urea, ammonium molybdate 0.245
g (1.986 mmol) in 130 g of α-chloronaphthalene.
Heat to 0 ° C. Thereto 4.92 pyridine-3,4-dicarboxylic acid
g (29.43 mmol), ammonium molybdate 0.245 g (1.98 mm
ol) and 1.00 g (7.34 mmol) of anhydrous zinc (II) chloride are added in small portions. The temperature was further increased, and the mixture was heated and stirred at 170 to 180 ° C. for 7 hours. After the completion of the reaction, the obtained blue solid was crushed, and ethanol, hot water,
A 5% aqueous solution of sodium hydroxide, water, a 5% aqueous solution of hydrochloric acid, and water were sequentially washed and dried. 1.74 g of the obtained pigment (yield 40
%)Met.

〔Example〕

 Hereinafter, the present invention will be described with reference to examples.

Example 1 An undercoat layer of 0.1 μm vinyl chloride-maleic anhydride-vinyl acetate copolymer resin was provided on an aluminum plate.

Next, 5 g of the above exemplified pigment (No. 1) was added to cyclohexanone 95
2 g of butyral resin (butyralization degree: 63 mol%, number average molecular weight: 20,000) was dissolved in ml, and the mixture was dispersed by a sand mill for 20 hours. This dispersion was applied on a previously formed undercoat layer using a Meyer bar so that the film thickness after drying was 0.5 μm, and dried to form a charge generation layer. Then the structural formula 5 g of a hydrazone compound and 5 g of a polymethyl methacrylate resin (number average molecular weight 100,000) are dissolved in 70 ml of chlorobenzene, and this is applied on a charge generating layer with a Meyer bar so that the film thickness after drying becomes 20 μm, and dried. Thus, a charge transport layer was formed to produce a photoreceptor of Example 1. The photoreceptors corresponding to Examples 2 to 25 were produced in exactly the same manner, using the other exemplary pigments shown in Table 1 in place of the pigment (No. 1).

The electrophotographic photoreceptor thus manufactured was corona-charged at −5.5 KV in a static manner using an electrostatic copying paper tester Model SP-428 manufactured by Kawaguchi Electric Co., Ltd., and was held for 1 second in a dark place. And the charging characteristics were examined. As the charging characteristics, the surface potential (V ₀ ) and the exposure amount (E1 / 2) required to attenuate the potential after dark decay for one second to half were measured. The surface potential V _R of exposure 30 seconds was measured. Table 1 shows the results.

Example 26 10 g of the pigment (No. 8) was dissolved in 80 g of concentrated sulfuric acid, then dropped into 200 ml of pure water, and neutralized with a 5% aqueous sodium carbonate solution to regenerate the pigment. The mixture was filtered, washed with warm water, a 5% aqueous sodium carbonate solution and warm water in this order, and dried under reduced pressure to obtain a blue pigment having a metallic luster. A corresponding photoreceptor was produced in the same manner as in Example 1 except that the pigment obtained here was used in place of the pigment (No. 1) of Example 1, and evaluated in the same manner as in Examples 1 to 25. . Table 2 shows the results.

Examples 27 to 30 In a 300 ml beaker were charged 100 ml of glass beads having a particle diameter of 0.3 mm, and 3.0 g of a pigment (No. 11) and ortho-dichlorobenzene 1
50 ml was added and the mixture was heated and stirred at 120 ° C. for 5 hours. After cooling to room temperature, the glass beads were separated, washed thoroughly with ethanol and then with warm water, and dried. A photoconductor was produced in the same manner as in Example 1 except that the pigment thus obtained was used in place of the pigment (No. 1) in Example 1, and evaluated in the same manner as in Examples 1 to 25. In addition, the same evaluation was performed by changing the pigment, 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.

Example 31 A pigment (No. 12) was vacuum-deposited on an aluminum substrate so as to have a thickness of 100 mg / m ² to form a charge generation layer. Then the structural formula 5g of a benzylidene compound and 5g of a bisphenol Z-type polycarbonate resin (viscosity average molecular weight 30,000) dissolved in 32.5g of monochlorobenzene are applied on the charge generation layer so that the film thickness after drying becomes 20µm, and charge transport is performed. A layer was formed. The charging characteristics of the photoreceptor thus manufactured were measured in the same manner as in Example 1. Table 4 shows the results.

Examples 32 to 35 Using the photoreceptors used in Examples 1, 12, 17, and 25, fluctuations in the light portion potential and the dark portion potential during repeated use were measured. As a method, a photoreceptor was attached to a cylinder of an electrophotographic copying machine equipped with a -5.6 KV corona charger, an exposure optical system, a developing device, a transfer charger, a charge removing exposure optical system and a cleaner. With the drive, an image is obtained on the transfer paper. Using this copier, the initial light potential (V _L ) and dark potential (V _D ) are set to around -100 V and -600 V, respectively, and the light potential (V _L ) and dark potential after 5,000 uses. (V _D ) was measured. Table 5 shows the results.

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

Comparative Examples 1-3 Charging characteristics were evaluated in exactly the same manner as in Examples 1 to 25 except that the phthalocyanine pigment represented by the following structural formula was used instead of the pigment (No. 1) of Example 1. Table 6 shows these results and the corresponding measurement results for the pigment of the present invention.

From the results shown in Table 6, it can be seen that the electrophotographic photoreceptor using the pigment of the present invention has high sensitivity and excellent low residual potential.

[Effects of the Invention] As described above, the tetraazaporphyrin derivative and the tetraazaporphyrin metal complex salt derivative of the present invention form an electrophotographic photoreceptor having extremely high sensitivity and excellent potential stability upon repeated use. You can do it.

Continuation of the front page (72) Inventor Nobuyoshi Kure 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-63-95460 (JP, A) JP-A-63-141070 ( JP, A)

Claims (1)

(57) [Claims] 1. An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer has a general formula (1) (Where X represents a hydrogen atom, a deuterium atom or an alkali metal atom, and A may have a substituent Or Represents A) a tetraazaporphyrin derivative represented by the general formula (II) (Wherein, M represents a metal atom other than a silicon atom and an alkali metal, Y represents a halogen atom, a hydroxyl group, an alkoxy group, or an oxygen atom. Further, n is an integer of 0, 1 or 2, and A is An electrophotographic photoreceptor comprising at least one selected from the group consisting of tetraazaporphyrin metal complex salt derivatives represented by the following general formula (I):