JP2599170B2 - Electrophotographic photoreceptor - Google Patents

Description

The present invention relates to an electrophotographic photoreceptor using phthalocyanine containing vanadium as a central metal, and more particularly, to an excellent exposure sensitivity. The present invention relates to an electrophotographic photosensitive member having characteristics and wavelength characteristics.

(Prior Art) Conventionally, as an electrophotographic photoconductor, a photoconductor using an inorganic photoconductor such as selenium, a selenium alloy, zinc oxide, cadmium sulfide, and tellurium has been mainly used. In recent years, the development of semiconductor lasers has been remarkable, and small and stable laser oscillators have become available at low cost, and have begun to be used as light sources for electrophotography. However, using a semiconductor laser that oscillates short-wavelength light in these devices has many problems in view of life, output, and the like. Therefore, materials that have been used in the short wavelength region, which have been used in the past, are not suitable for use in semiconductor lasers, and there is a need to study materials that have high sensitivity in the long wavelength region (780 nm or more). Was. In recent years, studies on organic photoconductors in which organic materials, particularly phthalocyanine, which is expected to have a sensitivity in a long wavelength region, are laminated and laminated with these materials have been actively conducted. For example, as a divalent metal phthalocyanine,
ε-type copper phthalocyanine (ε-CuPc), X-type metal-free phthalocyanine (X-H2Pc), τ-type metal-free phthalocyanine (τ-
H2Pc) has sensitivity in the long wavelength region. Examples of trivalent and tetravalent metal phthalocyanines include chloroaluminum phthalocyanine (AlPcCl), chloroaluminum phthalocyanine chloride (ClAlPcCl), titanyl phthalocyanine (TiOPc), and chloroindium phthalocyanine (InPcC).
l) and then contacting it with a vapor of a soluble solvent to increase the wavelength and sensitivity (Japanese Patent Application Laid-Open Nos.
No. 9-166959), a method of subjecting a phthalocyanine containing Ti, Sn and Pb as a Group IV metal to long-wavelength treatment using various substituents, derivatives or shifting agents such as crown ethers (Japanese Patent Application No. 59-59). No. 36254, Japanese Patent Application No. 59-204045
No.), sensitivity is obtained in the long wavelength region.

The use of vanadyl phthalocyanine (VOPc) as a charge generating agent for an electrophotographic photoreceptor is disclosed in JP-A-54-149634,
JP-A-57-146255, JP-A-57-147641, JP-A-57-146255
148747, JP-A-57-148748, etc.
The charge generating agent is limited to a compound having the chemical structural formula of VOPc. Further, the charge transfer agent is also limited to the benzidine derivative, oxadiazole derivative, triphenylmethane derivative, hydrazone derivative and 2,4,7-trinitro-9-fluorenone (TNF). However, the photoreceptors obtained by these methods are not only low in sensitivity but also have a drawback in that dark decay, which is an important necessary property of electrophotographic characteristics, is large. Furthermore, benzidine derivatives, oxadiazole derivatives, triphenylmethane derivatives, and hydrazone derivatives are not practical photoreceptors because of their instability to ultraviolet light, and TNF is used due to its toxicity. I can't do that. Thus, it was used until now
At present, practical photoconductors have not been obtained with the combination of VOPc and the above-mentioned charge transfer agent.

LEDs are also in practical use as digital light sources for printers. Although LEDs in the visible light range are also used, those that are generally put into practical use have an oscillation wavelength of 650 nm or more, typically 660 nm. Azo compounds, perylene compounds,
Selenium, zinc oxide, etc. cannot be said to have sufficient photosensitivity at around 650 nm, but phthalocyanine compounds have an absorption peak at around 650 nm, so they can be used as effective materials as charge generators for LEDs.

(Problems to be Solved by the Invention) An object of the present invention is to provide an electrophotographic photoreceptor having not only excellent exposure sensitivity characteristics and wavelength characteristics but also deterioration resistance characteristics, printing durability, and image stability when used repeatedly over a long period of time. Is to get

[Configuration of the invention]

(Means and Actions for Solving the Problems) The present invention relates to an electrophotographic photosensitive member using a charge generating agent and a charge transfer agent on a conductive support. And an electrophotographic photoreceptor which is a vanadium phthalocyanine compound represented by the formula:

(Wherein, R _{2 to} R ₄ represent a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group, provided that R _{2 to} R ₄ are not all hydrogen atoms. K, l, m, and n are And an integer of 0 to 4.) Further, in an electrophotographic photoreceptor obtained by laminating a charge generation layer and a charge transfer layer on a conductive support, the charge generation agent may be the above-mentioned vanadium phthalocyanine compound. The present invention relates to a characteristic electrophotographic photosensitive member.

Further, in an electrophotographic photoreceptor obtained by laminating a charge generation layer and a charge transfer layer on a conductive support, the charge generator is the vanadium phthalocyanine compound according to claim 1, and the charge transfer agent is represented by the general formula: The present invention relates to an electrophotographic photoreceptor, which is a compound represented by [II].

(Wherein, R ₅ and R ₆ are a hydrogen atom, an alkyl group, an alkoxy group or an aryl group, R ₇ , R ₈ , and R ₉ are a hydrogen atom or —NR ₅
It represents a (R ₆ ) group, and n is 0 or 1. The vanadium phthalocyanine compound of the present invention is a compound having a substituent on the central vanadium metal and / or the benzene ring on the outer ring, and the substituent may be any of the general formula [I]. , May be a mixture of two or more. Further, any vanadium phthalocyanine compound represented by the general formula [I] may have any crystal form and X
It may have a line diffraction pattern. The method for producing the vanadium phthalocyanine compound of the present invention will be described.

Phthalocyanine can be obtained by the phthalodinitrile method in which phthalodinitrile and a metal compound are heated and melted or heated in the presence of an organic solvent, the phthalic anhydride in the form of the Weyler method in which phthalic anhydride is heated by melting with urea and metal chloride or heated in the presence of an organic solvent, There is a method in which benzamide and a metal salt are reacted at a high temperature, and a method in which dilithium phthalocyanine is reacted with a metal salt, but is not limited thereto. Examples of the organic solvent include α-chloronaphthalene, β-chloronaphthalene, α-methylnaphthalene, methoxynaphthalene, diphenylethane, ethylene glycol, dialkyl ether, quinoline, sulfolane, and dichlorobenzene. desirable.

Also, a method of synthesizing a metal phthalocyanine having a substituent by a method of adding a substituent to a phthalocyanine raw material such as phthalodinitrile, indolene compound, indolenine compound, phthalic anhydride, cyanobenzamide, and condensing with a metal compound. Can be done. According to the above-mentioned method, the obtained product is acid, alkali, acetone, methyl ethyl ketone, tetrahydrofuran, pyridine, quinoline, sulfolane, α-chloronaphthalene, toluene, dioxane, xylene, chloroform, carbon tetrachloride, dichloromethane, dichloroethane, trichloropropane. , N, N'-dimethylacetamide, N-methylpyrrolidone, N, N'-dimethylformamide and the like. Purification methods include dissolution washing, recrystallization, extraction methods such as Soxhlet, and hot suspension. It is also possible to perform sublimation purification. The purification method is not limited to these.

The X-ray diffraction peak of the compound may be arbitrary.

The vanadium phthalocyanine compound synthesized and purified by the above method is further refined by a chemical refinement method such as an acid pasting method and an acid slurry method or a mechanical grinding method and used as a charge generating agent. If necessary at the time of grinding, a grinding aid such as salt or silica gel can be used.

In addition, the equipment used during grinding is a kneader,
Banbury mixer, attritor, edge runner mill, roll mill, ball mill, sand mill, SPEX mill,
Examples include, but are not limited to, homomixers, dispersers, agitators, jaw crushers, stamp mills, cutter mills, micronizers, and the like.

The charge generation layer using the vanadium phthalocyanine compound of the present invention is a uniform layer having a large light absorption efficiency, between particles in the charge generation layer, between the charge generation layer and the charge transfer layer, between the charge generation layer and the undercoat layer. In addition, there are few gaps between conductive substrates, and there are many characteristics such as potential stability, prevention of rise in bright area potential, etc. as an electrophotographic photoreceptor, and reduction of image defects and printing durability during repeated use. Can be obtained.

The n-type photoreceptor is formed by sequentially laminating an undercoat layer, a charge generation layer, and a charge transfer layer on a conductive substrate. The p-type photoreceptor is formed by laminating a charge transfer layer and a charge generation layer in this order on an undercoat layer, or by dispersing and coating a charge generation agent and a charge transfer agent together with an appropriate resin on the undercoat layer. Something was done. If necessary, an overcoat layer can be provided on both photoconductors for the purpose of protecting the surface and preventing filming with toner.

The vanadium phthalocyanine compound of the present invention is suitably used for all of the above various photoreceptors. The charge generation layer can be obtained by dispersing and coating a vanadium phthalocyanine compound and a resin with an appropriate solvent. If necessary, the charge generating layer can be used by dispersing and coating without the resin.

Although it is known that a charge generation layer is obtained by vapor deposition, the material obtained according to the present invention is processed to fine primary particles, and the crystals are extremely prepared by a suitable solvent. Since the impurities that have been removed are removed, vapor deposition can be performed very efficiently, and this is also effective as a material for vapor deposition.

Coating of photoreceptor is done by spin coater, applicator,
Spray coater, bar coater, immersion coater, doctor blade, roller coater, curtain coater,
Drying is preferably performed by heating and drying at 40 to 200 ° C. for 10 minutes to 6 hours under static or blowing conditions. After drying, the film is coated to have a thickness of 0.01 to 5 microns, preferably 0.1 to 1 micron.

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-vinylcarbol, polyvinylanthracene, and polyvinylpyrene. Preferably, polyvinyl butyral, polyarylate (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide resin, polyamide resin, polyvinylpyridine, cellulose resin, urethane Resin, ethoxy resin, silicone resin, polystyrene, polyketone resin, polyvinyl chloride,
Insulating resins such as polyvinyl chloride copolymer, polyvinyl acetal, polyacrylonitrile, phenolic resin, melamine resin, casein, polyvinyl alcohol, and polyvinylpyrrolidone can be exemplified. The resin contained in the charge generation layer is suitably at most 100% by weight, preferably at most 40% by weight. These resins may be used alone or in combination of two or more. The solvent for dissolving these resins differs depending on the type of the resin, and it is preferable to select a charge generation layer or an undercoat layer, which will be described later, from those that do not affect the coating. Specifically, benzene, xylene, ligroin,
Aromatic hydrocarbons such as monochlorobenzene and dichlorobenzene, ketones such as acetone, methyl ethyl ketone and cyclohexanone, alcohols such as methanol, ethanol and isopropanol, esters such as ethyl acetate and methyl cellosolve, carbon tetrachloride, chloroform, Aliphatic halogenated hydrocarbons such as dichloromethane, dichloroethane, and trichloroethylene; ethers such as tetrahydrofuran, dioxane and ethylene glycol monomethyl ether; N, N-dimethylformamide;
Amides such as N, N-dimethylacetamide and sulfoxides such as dimethyl sulfoxide are used.

The charge transfer layer is formed by dissolving and dispersing the charge transfer agent alone or in a binder resin. The charge transfer agent used in the present photoreceptor is preferably a compound represented by the general formula [II], but is not limited thereto.

(Wherein, R ₆ and R ₇ are a hydrogen atom, an alkyl group, an alkoxy group or an aryl group, and R ₈ , R ₉ and R ₁₀ are a hydrogen atom or —NR
_{6 represents a} (R ₇ ) group, and n is 0 or 1. A particularly preferred example of the general formula [II] is a compound in which R ₄ and R ₅ are both ethyl groups and R _{6 to} R ₈ are hydrogen atoms, or any of R _{6 to} R ₈ is —NC ₂ H ₅ (C ₂ H ₅ ).

The charge transfer materials can be used alone or in combination of two or more. The resin used for the charge transfer layer is silicon resin, ketone resin, polymethyl methacrylate,
Insulating resin such as polyvinyl chloride, acrylic resin, polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl butyral, polyvinyl formal, polysulfone, polyacrylamide, polyamide, chlorinated rubber, and poly- N-vinyl carbazole, polyvinyl anthracene, polyvinyl pyrene and the like are used.

The coating method is performed using a spin coater, an applicator, a spray coater, a bar coater, a dipping coater, a doctor blade, a caller coater, a curtain coater, and a bead coater.
Micron, preferably 10 to 20 micron is good. In addition to these layers, an undercoat layer can be provided on the conductive substrate for the purpose of preventing a decrease in chargeability and improving adhesion. Nylon as undercoat layer
Polyamides such as 6, nylon 66, nylon 11, nylon 610, copolymerized nylon, and alkoxymethylated nylon, metal oxides such as casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, gelatin, polyurethane, polyvinyl butyral, and aluminum oxide Object is used. It can also be adjusted by incorporating metal oxides such as zinc oxide and titanium oxide, and conductive and dielectric particles such as silicon nitride, silicon carbide and carbon Bragg into the resin.

The material of the present invention has absorption peaks at wavelengths of 800 mm or more and 650 nm, and is suitable not only as an electrophotographic photoreceptor for copying machines and printers but also as an absorbing material for solar cells, photoelectric conversion elements and optical disks.

(Examples) Hereinafter, examples of the present invention will be specifically described. Parts in the examples indicate parts by weight.

Example 1 10 parts of 3-chlorophthalodinitrile, phthalodinitrile
10 parts, 9.6 parts of vanadium pentoxide in 200 parts of quinoline, 220 ° C
, And the solvent was removed by steam distillation. Next, the sample was purified with acetone, and the sample was dried to obtain 21.4 parts of a vanadium phthalocyanine compound. The vanadium phthalocyanine compound obtained as a result of elemental analysis was VOPC-Cl 0.45
Having the following composition:

Example 2 A vanadium phthalocyanine compound was prepared in the same manner as in Example 1 except that 10 parts of 3-methoxyphthalodinitrile was used instead of 3-chlorophthalodinitrile.
20.8 parts were obtained. As a result of elemental analysis, the obtained vanadium phthalocyanine compound had a composition of VOPC (OCH ₃ ) 0.38.

Example 3 A vanadium phthalocyanine compound was prepared in the same manner as in Example 1, except that 10 parts of 2-methyl-1-amino-3-iminoisoindolenin was used instead of 3-chlorophthalodinitrile and phthalodinitrile. It was produced to obtain 20.3 parts. As a result of elemental analysis, the obtained vanadium phthalocyanine compound had a composition of VOPC (CH ₃ ) 0.82.

Next, a method for producing an electrophotographic photoreceptor using the vanadium phthalocyanine compound produced in Examples 1 to 3 as a charge generating agent will be described.

10 parts of copolymerized nylon (Amilan CM-8000 manufactured by Toray) was mixed with 190 parts of ethanol in a ball mill for 3 hours, and the resulting coating solution was dissolved in polyethylene terephthalate (PET).
After coating with a wire bar on a sheet on which aluminum was deposited on the film, the sheet was dried to obtain a sheet having an undercoat layer having a thickness of 0.5 μm.

2 parts of the vanadium phthalocyanine compound obtained in this example were dispersed in a ball mill for 6 hours together with a resin solution obtained by dissolving 1 part of a vinyl chloride-vinyl acetate copolymer resin (VMCH manufactured by Union Carbide) in 97 parts of THF.

This dispersion is applied on the undercoat layer, dried and
A micron charge generation layer was formed.

Next, as a charge transfer agent, 1 part of the exemplified compound (II-a) of the compound of the general formula [II] and 1 part of a polycarbonate resin (Panlite L-1250 manufactured by Teijin Chemicals Ltd.) were mixed with methylene chloride 8 parts.
And mixed and dissolved. This solution was applied on the charge generation layer and dried, and then a 15-micron charge transfer layer was formed, and the electrophotographic characteristics were measured.

The electrophotographic characteristics of the photoreceptor were measured by the following method.

Static mode 2, corona charging is -5.2KV, irradiating white light with surface potential and 5Lux or light adjusted to 800nm of 1μW by electrostatic copying paper tester SP-428 (manufactured by Kawaguchi Electric). The white light half-life exposure sensitivity (E1 / 2) was examined from the time to decrease to 1/2. Spectral sensitivity was measured by applying a corona charge of -5.2 KV to the photoreceptor using an electrostatic charging tester, and irradiating it as a monochromatic light with a monochromator (manufactured by Joban Yvon) using a 500 W xenon lamp as a light source. , Was measured by the light decay at the time of the charge drop.

 Table 1 shows the results of the electrophotographic characteristics.

Example 4 A vanadium phthalocyanine compound prepared under the same conditions as in Example 1 was coated on a PET film having an undercoat layer by 10 ^-5 Torr.
Under the vacuum conditions described above, a charge generation layer having a thickness of 0.15 μm was obtained. A charge transfer layer was formed thereon under the same conditions as in Example 1, and the electrophotographic characteristics were measured. The results are shown in Table 2.

The photoreceptor having a charge generation layer using vanadium phthalocyanine of the present invention had almost the same sensitivity in both the dispersion method and the vapor deposition method.

Comparative Examples 1-4 An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that vanadyl phthalocyanine (VOPc) was used as a charge generating agent and the compounds shown in Table 3 were used as a charge transfer agent. Compared.

Table 4 shows the results of the electrophotographic characteristics of Comparative Examples 1 to 4.

From the results shown in Table 4, the electrophotographic photosensitive members of Comparative Examples 1 to 4 were significantly lower in sensitivity than Examples 1 to 4.

Further, the photoreceptors prepared in Examples 1 to 4 and Comparative Examples 1 to 4 were left under 600 (lux) white light for 30 minutes. The surface potential of the photoreceptor before and after standing was measured to compare the optical memory properties.

 The results are shown in Table 5.

From the results shown in Table 5, the vanadium phthalocyanine compound of the present invention and the photoreceptors of Examples 1 to 4 were 600 (lu
x) While the potential difference before and after irradiation was 15 (V) or less, the potentials of Comparative Examples 1 to 4 were significantly reduced. From the above results, it was confirmed that the photoreceptor of the present invention also has light stability in addition to excellent sensitivity and spectral sensitivity.

Further, the following vanadium phthalocyanine compound was prepared, and the electrophotographic characteristics were measured (the charge transfer agent and other conditions were the same as in Examples 1 to 4). The results are shown in Table 6.

[Effects of the Invention] According to the present invention, an electrophotographic photoreceptor having not only excellent exposure sensitivity characteristics and wavelength characteristics but also deterioration resistance characteristics, printing durability, and image stability when used repeatedly over a long period of time can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication location C09B 47/22 C09B 47/22 G03G 5/06 372 G03G 5/06 372

Claims (4)

(57) [Claims] 1. An electrophotographic photoreceptor comprising a charge generating agent and a charge transfer agent on a conductive support, wherein the charge generating agent is a vanadium phthalocyanine compound represented by the general formula [I]. An electrophotographic photosensitive member characterized by the following. (Wherein, R _{2 to} R ₄ represent a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group (provided that R _{2 to} R ₄ are not all hydrogen atoms), k, l, m and n is 0 to
Represents an integer of 4. ) 2. An electrophotographic photosensitive member comprising a charge generating layer and a charge transfer layer laminated on a conductive support, wherein the charge generating agent is the vanadium phthalocyanine compound according to claim 1. Photoreceptor. 3. An electrophotographic photosensitive member comprising a charge generating layer and a charge transfer layer laminated on a conductive support, wherein the charge generator is the vanadium phthalocyanine compound according to claim 1, wherein the charge transfer agent is An electrophotographic photosensitive member, which is a compound represented by the general formula [II]. (Wherein, R ₅ and R ₆ are a hydrogen atom, an alkyl group, an alkoxy group or an aryl group, R ₇ , R ₈ , and R ₉ are a hydrogen atom or —NR ₅
It represents a (R ₆ ) group, and n represents 0 or 1. ) 4. The electrophotographic photoreceptor according to claim 2, wherein an inorganic or organic subbing layer is provided on the conductive support.