JPS6355058B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a photosensitive plate used in electrophotography, and particularly to an electrophotographic plate with excellent printing durability. In composite electrophotographic plates containing a charge generating substance and a charge transporting substance as constituent components, conventionally, inorganic compounds such as selenium, cadmium sulfide, and zinc oxide, and organic materials such as disazo pigments, phthalocyanine pigments, and perylene pigments are used as charge generating substances. Also, for example, trinitrofluorenone, pyrazoline derivatives, polyvinylcarbazole, etc. are used as charge transport substances. At that time, various synthetic resins and cellulose derivatives have often been blended with charge transport materials as binders to contribute to the formation of photoreceptor layers. Electrophotographic plates with the above-mentioned material composition have good characteristics, but their high sensitivity range is limited to visible light wavelengths (400 to 700 nm), and their service life is limited to about 50,000 sheets per page at most. In particular, there was a problem in that printing characteristics deteriorated due to surface roughness caused by friction with paper, that is, printing durability was poor. Regarding the first problem, the present inventors have solved the problem by including a polymer or copolymer of 9-(p-vinylphenyl)anthracene as a charge transporting material and combining it with a copper phthalocyanine pigment as a charge generating material. discovered that the high-sensitivity region could be extended to longer wavelengths (Japanese Patent Application No. 17836/1983, etc.). However, since a known resin was used as the binder, the printing durability was not sufficient. The second method of improving printing durability has been to use thermosetting resins or highly hard and transparent materials.
Proposals have been made to use it as a binder or a hard surface layer. However, in those materials,
Since the residual charge, which is important as an electrophotographic characteristic, is not completely removed, the resulting copies and prints have poor image quality with a lot of fog. An object of the present invention is to overcome the above-mentioned difficulties found in conventional materials and to provide an electrophotographic plate with improved printing durability without deteriorating electrophotographic properties. A feature of the present invention is that in an electrophotographic plate comprising a charge generation layer containing a charge generation substance on a conductive substrate and a charge transfer layer containing a charge transport substance layered thereon, a binder for the charge transfer layer is used. is()(a) General formula (1) (In the formula, X represents hydrogen or a bromine atom) 9-(p-vinylphenyl)anthracene structural unit; (b) General formula (2) (In the formula, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents -NHCH ₂ OR ₃ (However, R ₃ represents a hydrogen atom or an alkyl group having 4 or less carbon atoms), -OR ₄ (However, R ₄ represents a hydrogen atom, an alkyl group having 4 or less carbon atoms, a 2-ethylhexyl group, a 2-hydroxyethyl group, a 2-hydroxypropyl group, or a 1,2-epoxypropyl group). A copolymer containing () General formula (3) (In the formula, R ₅ , R ₆ and R ₇ are each a hydrogen atom,
represents an alkyl group, a phenyl group, a hydroxyl group, an amino group, an amino group substituted with an alkyl group, an amino group substituted with a hydroxymethyl group, or an amino group substituted with an alkoxymethyl group, and R ₅ , R ₆ and at least one of R ₇ is an amino group substituted with a hydroxymethyl group or an amino group substituted with an alkoxymethyl group. Our goal is to provide electrophotographic plates. One of the repeating structural units of the copolymer used in the present invention has the general formula

[Formula] (wherein, X represents hydrogen or bromine atom), and its monomers, 9-(p-vinylphenyl)anthracene and 9-(p-vinylphenyl)
-10-bromoanthracene and their polymers,
The copolymer is published in Japanese Patent Publication No. 40-40079, 49-11949, 49-
43893, 50-21855 and US Pat. No. 4,125,701. In addition, other repeating structural units have the general formula (The meanings of R ₁ and R ₂ in the formula are the same as described above.) An acrylic derivative represented by, for example, N
-(Hydroxymethyl)acrylamide, N-(ethoxymethyl)methacrylamide, N-(butoxymethyl)acrylamide, acrylic acid, methacrylic acid, ethyl acrylate, butyl acrylate,
Examples include unit structures such as butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, glycidyl acrylate, and glycidyl methacrylate. The copolymer () is crosslinked and cured by reaction with a triazine compound (). As the curing agent, the following compounds can be used. The composition of the copolymer () of the present invention is (a) 9-(p
-Vinyl phenyl) anthracene unit and (b) acrylic monomer unit expressed as a molar ratio of 1:100
The ratio is preferably in the range of 1:2 to 1:2, particularly 1:20 to 1:3. When the value of the molar ratio is larger than this range, residual charge tends to increase, and when it is smaller, sufficient printing durability cannot be obtained. In addition, copolymers () and triazine compounds ()
It is desirable to mix 0.1 to 500 parts by weight of the latter to 100 parts by weight of the former, and particularly good results are obtained when the latter is 200 parts by weight or less. This is because as the amount of the triazine compound increases, the electrophotographic properties deteriorate, and if it is too small, no improvement in printing durability can be expected. In the present invention, the two-component resin material not only serves as a binder to improve printing durability, but also serves to extend the high sensitivity range to wavelengths longer than visible light. In the present invention, good photosensitivity can be obtained by using a charge-generating substance and a charge-transporting substance in the resin material, and in particular, using an electron-accepting compound as the charge-transporting substance,
This is suitable for improving sensitivity characteristics. As the charge-generating substance, known organic pigments such as monoazo pigments, disazo pigments, phthalocyanine pigments, perylene pigments, cyanine pigments, polycyclic quinone pigments, and indigoid pigments are suitably used.
Furthermore, selenium and its alloys, cadmium sulfide, cadmium selenide, cadmium telluride,
Inorganic materials such as zinc oxide, antimony sulfide, antimony selenide, arsenic sulfide, arsenic selenide are also used. On the other hand, an electron donating compound can be used as the charge transporting substance. Such compounds include, for example, tetracyanoethylene, o-bromoanyl, o-chloroanyl, p-bromoanyl, p
-Chloranil, p-iodoanil, 2,5-dichloro-p-benzoquinone, 2,6-dichloro-
p-benzoquinone, 1,2-dicarboxy-1,
2-dicyanoethylene, chloro-p-benzoquinone, maleic anhydride, 2,4,6-trinitrobenzoic acid, 1,3,5-trinitrobenzene, tetranitromethane, 2,4,6-trinitroanisole, tetrachlorophthalanhydride acid, picryl chloride, 3,5-dinitrobenzonitrile, 2,4,
7-trinitro-9-fluorenylidene malononitrile, 2,4,5,7-tetranitrocarbazole, 2,2',4,4'-tetranitrobiphenyl, tetracyanoquinodimethane, 1,2,4 ,5
-tetracyanobenzene, tetrabromophthalic anhydride, p-fluoroanyl, 2,3-dichloronaphthoquinone, 1,8-dichloroanthraquinone,
1-Chlornaphthoquinone, 3,4,5,6-tetrachlorophthalimide, 2,6-dichloroquinone-4-chloroimide, 2,3-dichloro-5,6
-dicyano-p-benzoquinone, acetyl-p-
Benzoquinone, bromo-p-benzoquinone, 2,
6-dibromo-p-benzoquinone, 2,3-dichloro-p-benzoquinone, trichloro-p-benzoquinone, methyltrichlor-p-benzoquinone, cyano-p-benzoquinone, 2,3-dicyano-p-benzoquinone, tetracyano-p -benzoquinone, fluoro-p-benzoquinone, iodo-p-benzoquinone, nitro-p-benzoquinone, 2,6-dinitro-p-benzoquinone, dibromo-1,4-naphthoquinone, 2,3-dichloro-5-nitro-1 , 4-naphthoquinone, 2,3-
dicyano-1,4-naphthoquinone, 2,3-dicyano-5-nitro-1,4naphthoquinone, 2,
3,5,6-tetrachloro-7-nitro-1,4
-naphthoquinone, 2,3-dicyano-5,6-dichloro-7-nitro-1,4-naphthoquinone,
2,4-dinitrofluorenemalononitrile,
2,5-dinitrofluorenemalononitrile,
2,6-dinitrofluorene malononitrile,
2,7-dinitrofluorene malononitrile,
3,6-dinitrofluorenemalononitrile,
2,4,5,7-Tetranitrofluorenemalononitrile, pentacyanobenzonitrile, pentacyanobenzonitrile, pentacyanomethylbenzene, tetrafluorotetracyanoquinodimethane, benzorylacetonitrile, dicyanomethylene-indene-1,3- Examples include dione, hexacyanobutadiene, 3,5-dinitrophthalic anhydride, and diphenoquinone. The electrophotographic plate of the present invention has a structure in which a layer of a charge-generating substance (charge-generating layer) and a layer of a charge-transporting substance (charge-transporting layer) are laminated. In the laminated type, there are two methods: forming a charge generation layer on a conductive substrate and then forming a charge transport layer thereon, and vice versa. method is possible. At that time, the resin material can be blended into either the upper or lower layer, but in a structure with the charge transport layer as the upper layer, blending and using it only in this layer can achieve both printing durability and electrophotographic properties. Therefore, it is particularly preferable. In the case of a stacked structure, the thickness of the charge generation layer is 0.1 to 5μ.
m, the charge transport layer is preferably formed to have a thickness of 5 to 50 μm. A suitable ratio of the resin material in the charge transport layer is 25 to 200 parts by weight of the charge transport material to 100 parts by weight of the resin material;
When used in the charge generation layer, the appropriate ratio is 50 to 500 parts by weight of the charge generation substance per 100 parts by weight of the resin material. In the present invention, a uniform layer or charge generating layer and a charge transport layer are formed as described above on a conductive substrate, such as an aluminum foil or a plastic sheet coated with a thin layer of aluminum. An undercoat layer may be provided on the substrate in advance in order to prevent peeling of these photosensitive layers and impart scorbability to the photosensitive layer.
The photosensitive layer is prepared by applying a coating solution prepared by dissolving necessary components of a charge generating substance, a charge transporting substance, and a resin material in an appropriate solvent according to the needs, using a well-known method such as a bar coater, a roll coater, an applicator, or a casting method. After coating and drying the solvent, the resin component is thermally cured to complete the process. Curing is performed at a temperature above about 100°C and below the melting point of the charge transport material.
This can be completed by heating, for example, at 120° C. for about 60 minutes. The effects of the present invention will be explained in more detail below using Examples. Example 1 In the method described in U.S. Pat. No. 4,125,701,
A 9-(p-vinifluphenyl)anthracene-isobutyl methacrylate copolymer (monomer unit molar ratio m/n) was prepared. That is, a mixture of 0.56 g of isobutyl methacrylate, 5.6 g of 9-(p-vinylphenyl)anthracene, 15.6 mg of t-butyl peroxide and 8 ml of xylene was heated at 130 DEG C. for 8 hours in a nitrogen gas stream. The obtained copolymer was washed with methanol and then vacuum dried.
It was further purified by reprecipitation twice in a dichloroethane-methanol system. By elemental analysis, the m/n ratio was determined to be 1:about 0.21. Next, a methylolmelamine mixture mainly consisting of hexamethylolmelamine was synthesized by the following method. i.e. melamine
31.5g, 67g of commercially available 37% formaldehyde, 14g of water
g was added thereto, and the mixture was stirred at 70° C. for 1 hour under a reflux condenser. During the reaction, sodium hydroxide was added to adjust the pH of the solution to maintain it at 9.0. This reaction solution was poured into 2 to 3 times the volume of cold methanol to precipitate crystals, which were filtered and dried. An electrophotographic plate was prepared using the thus obtained copolymer and methylolmelamine as a hardening agent. First, ε-type copper phthalocyanine (Lionol Blue ES manufactured by Toyo Ink Company) was used as a charge generating substance.
Polycarbonate (Mitsubishi Gas Chemical Co., Ltd. Corpilon) was added to 100ml of 1% by weight toluene dispersion
S3000) in dichloromethane solution (concentration 1% by weight)
A coating liquid was prepared by adding 50ml. This coating liquid was applied onto an aluminum plate (10 cm x 15 cm) with a thickness of 100 μm using an applicator (manufactured by Toyo Seiki Co., Ltd.) and heated at 100°C.
A charge generation layer was prepared by drying for a period of time. Next, 10 g of the copolymer prepared by the above production method, 8 g of methylolmelamine, and 6 g of o-bromoanil were mixed in a mixed solvent of toluene and methyl ethyl ketone (7:3).
Volume ratio) was dissolved in 100 ml and coated on the charge generation layer in the same manner. 30 minutes at 100℃, then 130℃
The resin component was cured by heating for 1 hour. For this electrophotographic plate, an electrostatic recording paper tester (SP-428 manufactured by Kawaguchi Electric Co., Ltd.) was equipped with a visible light cut filter (manufactured by Kodatsu Co., Ltd., which cuts wavelengths below No. 750 nm), and the half-reduction exposure (E50) was 2.0 lux.・The value of seconds was obtained. Further, when a halogen lamp (500 W) was analyzed using a spectrometer and the half-decreased exposure amount was measured at a wavelength of 775 nm, a value of 10 mJ/m ² was obtained, indicating high sensitivity to long wavelength light. Next, this electrophotographic plate was installed in a homemade laser printer recording device and its characteristics were repeatedly examined. This device uses a semiconductor laser (oscillation wavelength: 780 nm) as a light source, and can automatically perform charging, exposure, development, and transfer many times. The electrophotographic plate was tested under the following conditions: a charging corona voltage of 5.5 kV, an exposure of 1 mW, a recording speed of 100 mm/s with a laser scanning width of 50 cm, and a pressure fixing type magnetic toner as the developer. It was found that there was no change in characteristics even after multiple printings, the surface was smooth, and the printing durability was extremely excellent. Comparative Example 1 An electrophotographic plate was produced in the same manner as in Example 1 except that methylolmelamine was used as the binder. When the electrophotographic characteristics of this electrophotographic plate were evaluated in the same manner as in Example 1, characteristic values of half-reduction exposure of 2.1 lux·sec (visible light cut filter) and 0.08 mJ/m ² (wavelength 1775 nm) were obtained. . In addition, when we similarly evaluated the printing durability, we found that
By the time the test was repeated 10,000 times, the sensitivity had already decreased to about 2/3, and the surface of the electrophotographic plate had unevenness due to friction with the paper, causing cloudiness. Example 2 Similar to Example 1, copolymers of various compositions (see table) synthesized based on the method described in U.S. Pat. An electrophotographic plate was prepared in the same manner as in Example 1, and its characteristics were investigated. As a result, it was found that all of them had a printing durability of 50,000 times or more. On the other hand, the printing durability of electrophotographic plates prepared using non-curing resins having the specifications shown in the table as Comparative Examples 2 and 3 was only about 5000 times and about 2000 times, respectively.

【table】

[Table] Values for parts by weight.
As described above, according to the present invention, it is possible to achieve both printing durability and electrophotographic properties, particularly high sensitivity to long wavelength light, and the electrophotographic plate can be suitably used for laser printers and facsimiles.

Claims (1)

[Scope of Claims] 1. In an electrophotographic plate comprising a charge generation layer containing a charge generation substance on a conductive substrate and a charge transfer layer containing a charge transport substance layered thereon, the bonding of the charge transfer layer is The agent is ()(a) General formula (1) (In the formula, X represents hydrogen or a bromine atom) 9-(p-vinylphenyl)anthracene structural unit; (b) General formula (2) (In the formula, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents -NHCH ₂ OR ₃ (However, R ₃ represents a hydrogen atom or an alkyl group having 4 or less carbon atoms), -OR ₄ (However, R ₄ represents a hydrogen atom, an alkyl group having 4 or less carbon atoms, a 2-ethylhexyl group, a 2-hydroxyethyl group, a 2-hydroxypropyl group, or a 1,2-epoxypropyl group). A copolymer containing () General formula (3) (In the formula, R ₅ , R ₆ and R ₇ are each a hydrogen atom,
represents an alkyl group, a phenyl group, a hydroxyl group, an amino group, an amino group substituted with an alkyl group, an amino group substituted with a hydroxymethyl group, or an amino group substituted with an alkoxymethyl group, and R ₅ , R ₆ and at least one of R ₇ is an amino group substituted with a hydroxymethyl group or an amino group substituted with an alkoxymethyl group. Electrophotographic board.