JPH0519491A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To offer an electrophotographic sensitive body having excellent electrical characteristics and stability to environmental changes as the sensitive body itself and having excellent printing resistance, making a picked-up image and printed matter almost free from pressure marks such as scratches and having such excellent desensitization reactivity that spotted ground stain of printed matter is not caused even by treatment by a single passage through an etching processor having a low treating effect when the sensitive body is used as an electrophotographic planographic printing plate. CONSTITUTION:In this electrophotographic sensitive body having a photoconductive layer based on an inorg. photoconductor and binding resin on the electric conductive substrate, the binding resin contains resin (A) and resin (B) in (8-3):(2-7) weight ratio (expressed in terms of solid matter). The resin A is a first resin compsn. obtd. by polymerizing an acrylic monomer mixture in the presence of alkyd resin and has (2.5-50):(97.5-50) weight ratio between the alkyd resin and the resulting polymer. The resin B is a second resin compsn. obtd. by polymerizing an acrylic monomer mixture and has 2.0-10.0 acid value.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrophotographic photoreceptor,
More specifically, the present invention relates to an electrophotographic photosensitive member which is excellent in imageability, electrical characteristics, stability against environmental changes, and is excellent in printing durability, desensitizing reactivity, and desensitizing film forming performance as an electrophotographic lithographic printing plate.

[0002]

2. Description of the Related Art An electrophotographic photosensitive member composed of a conductive support and a photoconductive layer is used in an image formation by charging, exposing and developing which is a general electrophotographic process. Further, after the image formation, lithographic printing is performed. The method used as a printing plate is widely used. The binder resin used for forming the photoconductive layer of the electrophotographic photosensitive member is a film-forming resin itself, the adhesiveness of the formed photoconductive layer to the conductive support, and the binding of the inorganic photoconductive powder. It has good dispersibility in the resin and has suitable image quality and electrical characteristics as an electrophotographic photoreceptor, and its performance can be stably maintained without being affected by environmental changes during image pickup. is necessary.

It has been known for a long time as a known resin for an electrophotographic photoreceptor that a silicone resin, an alkyd resin, an acrylic resin (acrylic acid ester copolymer or the like) and a mixture thereof are used. However, when these conventional resins are used, 1) the affinity for the inorganic photoconductive powder is insufficient and the dispersibility of the coating liquid becomes poor, 2) the reproducibility of the copied image is poor, and 3) ) Sensitive to environmental changes (from high temperature and high humidity to low temperature and low humidity) during imaging, 4) When used as a lithographic printing plate, the film strength and adhesive strength of the photosensitive layer are insufficient and peeling of the photosensitive layer occurs during printing. 5) There were any problems such as low reactivity with the desensitizing liquid as a lithographic printing plate and causing background stains on the printed matter.

As an improvement of the binder resin of the photoconductive layer, for example, in JP-A-60-10254, an acrylic resin having an acid value of 4 to 50 is used as a component having a distribution of average molecular weight of 10 ³ to 10 ^4.
A method of improving imageability, electrical characteristics, moisture resistance and the like by using together components having a distribution of 10 ^{4 to} 2 × 10 ⁵ is disclosed. Further, research on a lithographic printing plate using an electrophotographic photosensitive member has been earnestly conducted, and a binder resin for a photoconductive layer that has both imageability and electric characteristics as an electrophotographic photosensitive member and printability as a printing plate. For example, in Japanese Patent Publication No. 50-31011, the molecular weight MW 1.8 obtained by copolymerizing a (meth) acrylate-based monomer with another monomer in the presence of fumaric acid.
A resin in which a resin having a glass transition point Tg of 10 to 80 ° C. at a temperature of × 10 ⁴ to 10 × 10 ⁴ and a copolymer composed of a (meth) acrylate-based monomer and a monomer other than fumaric acid is used in combination, JP-A-54-20735 and JP-A-57-202544 use a quaternary or quaternary copolymer containing acrylic acid and hydroxy (meth) acrylate.
In 68046, the one using a terpolymer containing a (meth) acrylic acid ester having an alkyl group having 6 to 6 carbon atoms as a substituent and a vinyl monomer containing a carboxylic acid is a desensitizing agent for the photoconductive layer. It is described that it is effective in improving.

However, even if the above-mentioned resin is considered to have an effect on the image quality, electrical characteristics, moisture resistance, etc., when actually evaluated and seen, the electrical characteristics such as charging property, light attenuation and dark attenuation retention rate are obtained. , Stain on non-image area, image quality such as image density, stability against environmental changes at the time of imaging (from high temperature and high humidity to low temperature and low humidity)
Etc. are not practically satisfactory, and since the film strength of the photoconductive layer surface is weak and the smoothness is high, indentations such as scratches are generated on the surface, which may cause stains on the imaged material and printed matter. there were.

Further, even with a binder resin which is said to be effective in improving the desensitizing property for electrophotographic lithographic printing plates, when actually evaluated, it is insensitive by hand etching having a high desensitizing treatment effect. When the degreasing treatment is performed, the spot stains are slightly generated, but when the desensitizing treatment is performed with an etching processor having a low desensitizing treatment effect which has been widely used in recent years, Uniform soiling occurs over the entire surface.

Therefore, when performing desensitizing treatment using an etching processor, conventionally, as a method for relieving background stains, there is a two-pass method in which a plate once treated by the etching processor is treated again by the etching processor. However, although the double pass method is effective for the background soil that is uniform over the entire surface, it is less effective for the spot-like background stain, and the double pass method is more effective than the hand etching process. Also, there is a tendency that there are many spots of stains on printed matter.

[0008]

Even when a binder resin for an electrophotographic photoreceptor having improved electrical characteristics, image quality, moisture resistance, etc., the environment at the time of imaging changes from high temperature and high humidity to low temperature and low humidity. In this case, it was found that maintaining stable performance was still insufficient, and further there were problems in dispersibility of the coating liquid, film strength on the surface of the photoconductive layer, smoothness and the like.

In the electrophotographic lithographic printing plate, dot-like background stains have a great influence on the value of the printed matter. Therefore, hand-etching and desensitization treatment by passing through the etching processor twice are performed to remove stains on the printed matter. A lithographic printing plate that does not cause the problem is required. Further, in recent years, the plate making machine and etching processor, or the etching processor and the printing machine, or the plate making machine, the etching processor and the printing machine, which are becoming popular, have been integrated.
The passing method is preferable in the process of the system, and it is desired to develop a lithographic printing plate that does not cause scumming on the printed matter even by desensitizing treatment by passing the etching processor once.

The present invention is to improve the above-mentioned problems of the conventional electrophotographic photosensitive member as follows. The object of the present invention is, as an electrophotographic photoreceptor, excellent in electrical characteristics,
Even when the environment at the time of image capturing changes from high temperature and high humidity to low temperature and low humidity, it maintains stable, clear, and good image quality,
Further, as an electrophotographic lithographic printing plate, it has excellent printing durability, scratches and other indentations are unlikely to occur on the imaged material and printed material, and it is a conventional type of hand etching, etching processor double-passing and etching with low processing effect. To provide a lithographic printing plate having excellent desensitizing reactivity and desensitizing film forming performance, which does not cause spot stains as well as uniform stains on the printed matter even by a single-processor treatment method. Is.

[0011]

The above object is to provide an electrophotographic photosensitive member having a photoconductive layer mainly composed of an inorganic photoconductor and a binder resin formed on a conductive support, wherein the binder resin is Containing resin (A) and resin (B) shown below,
The solid content weight ratio is resin (A) / resin (B) = 8 to 3 /
It has been found to be achieved by an electrophotographic photosensitive member characterized by being 2 to 7.

Resin (A): A first resin composition obtained by polymerizing an acrylic monomer mixture in the presence of an alkyd resin, wherein the weight ratio of the alkyd resin to the acrylic monomer mixture is Resin that is 2.5-50 / 97.5-50. Resin (B): A second resin composition obtained by polymerizing an acrylic monomer mixture, and having a resin acid value of 2.0 to 10.0.

The characteristic feature of the binder resin of the present invention is that the resin (A) obtained by polymerizing an acrylic monomer mixture in the presence of an alkyd resin, an acrylic monomer mixture and an unsaturated acid copolymerized therewith. It is composed of a resin (B) obtained by adjusting the acid value of the resin according to the weight ratio of and polymerizing. When only the resin (A) of the present invention is used as a binder resin, poor dispersion of the coating liquid may occur, the presence of aggregates on the surface of the photoconductive layer, insufficient film strength of the photoconductive layer, and a conductive support. Peeling of the photoconductive layer due to insufficient adhesion of the photoconductive layer,
There is a problem that the photoconductive layer surface has high smoothness, and scratches and other indentations are likely to occur.In addition, in electrophotographic characteristics, the image density of the captured image is excellent, but the non-image area has scumming and stains. There are problems such as deterioration of image quality at high temperature and high humidity.

Further, when an electrophotographic planographic printing plate is used,
It has an excellent performance that the printed matter does not have a uniform background stain even if it is passed once through the etching processor, but it causes problems such as spots or partial background stains of the printed matter due to aggregates and indentations on the photoconductive layer surface. There is. When the resin (B) of the present invention is used alone as a binder resin, the dispersibility of the coating liquid,
It has good stability against environmental changes during imaging, but it has problems such as indentations due to excessively high dispersion of photoconductive powder and resin due to high surface smoothness, and low image density in electrophotographic characteristics. In addition, the electrophotographic lithographic printing plate has a problem that the printed matter has spot-like background stains by hand etching, and uniform background stains are generated by passing through the etching processor twice.

When the resin (A) and the resin (B) are used alone as a binder resin, the resin (A) contains an alkyd resin, and the resin (B) contains a certain amount of carboxylic acid. The resin (A) does not have an affinity with the photoconductive powder, and the resin (B) has an affinity with the photoconductive powder. Since the properties are too strong and the dispersibility with the photoconductive powder is not appropriate, it is considered that the above problems occur.

In the present invention, the resin (A) is mixed with the resin (B) to form a binder resin, so that the excellent performance of the resin (A) and the resin (B) is not impaired, and the resin (A), An excellent electrophotographic photoreceptor and an electrophotographic lithographic printing plate were found by solving problems such as dispersibility of the resin (B), surface film strength of the photoconductive layer, adhesiveness and smoothness. In particular, when a resin (A) having a high smoothness and a resin (B) having a high smoothness were mixed, an unexpected performance that the smoothness was lowered was found, which was unexpected.

The mixture of acrylic monomers used for producing the resin (A) and the resin (B) is obtained from acrylic acid or methacrylic acid and an alcohol having a hydrocarbon group having 1 to 12 carbon atoms. Esters, the typical examples of which are hydrocarbon groups are methyl group, ethyl group, n-butyl group, i-butyl group, t-butyl group, n-propyl group, isopropyl group, 2-ethylhexyl group and n- (Meth) acrylates such as lauryl group, cyclohexyl group and benzyl group, and styrene derivatives such as styrene, α-methylstyrene, p-bromostyrene and β-chlorostyrene as comonomer which are copolymerized as necessary, Organic nitriles such as acrylonitrile, methacrylonitrile, α-methylglutaronitrile, vinyl acetate, vinyl propionate, iso- Examples thereof include vinyl esters of organic acids such as vinyl ropionate, and further, as copolymerizable unsaturated acids, α / β-ethylenic non-ionic compounds such as acrylic acid, methacrylic acid, itaconic acid, α-methyleneglutaroic acid and the like. Other copolymerizable carboxylic acids such as saturated carboxylic acid, crotonic acid, maleic acid, or hydroxyalkyl (meth)
Examples thereof include hydroxyl alkyl esters of α / β-ethylenically unsaturated carboxylic acids such as acrylates.

The resin (A) is obtained by polymerizing one kind or a combination of two or more kinds of the above acrylic monomers in the presence of an alkyd resin.
For example, a known alkyd resin having alcohol and phthalic acid as main components and modified with a fatty acid is used. As the denaturing fatty acid, known coconut oil, soybean oil, linseed oil,
Saffura oil, deer oil, etc. are used, and the oil length is short,
Either medium oil or long oil may be used.

Like the resin (A), the resin (B) is obtained by polymerizing one kind or a combination of two or more kinds of acrylic monomers, but the resins are mixed so that the resin acid value becomes 2.0 to 8.0. Adjust the polymerizable unsaturated acid. The method for producing the polymer of the present invention is preferably ordinary solution polymerization, and as the polymerization solvent, hydrocarbons such as toluene and xylene, alcohols such as propanol and butanol, ketones such as acetone and methyl ethyl ketone, mineral spirits and the like. And the like, esters such as ethyl acetate and butyl acetate, and cellosolves such as ethyl cellosolve and bityl cellosolve can be used.

The polymerization initiator used for polymerizing the resin (A) and the resin (B) includes benzoyl peroxide, cumene hydroperoxide, lauryl peroxide, cyclohexanone peroxide, t-butyl hydroperoxide and the like. An azo compound such as a peroxide or azobisisobutyronitrile is used. Regarding the resin (A), a peroxide-based initiator is preferable because of the compatibility between the acrylic monomer and the alkyd resin.

Further, chain transfer agents such as mercaptans can be used if necessary. It is also possible to use other resin in combination with the resin composed of the resin (A) and the resin (B) of the present invention, and examples thereof include acrylic resin, epoxy resin, silicon resin, styrene resin, and the like. An acrylic resin having a low average molecular weight (for example, 10 ^{3 to} 3 × 10 ⁴ ) and a high acid value (for example, 10 to 100) is also included.

However, when the resin used in combination has a resin acid value, the total resin acid value of the resin used in combination with the resin (B) exceeds 10.0, or the total binder resin weight using the resin of the present invention. If it exceeds 30% by weight, the effect of the present invention is lost. When the content of the alkyd resin of the resin (A) is less than 2.5% by weight, the image quality, particularly the imageability at high temperature and high humidity, and the electrical characteristics are deteriorated, and when it is more than 50% by weight, the dispersibility and imageability are improved. In particular, the image quality and the desensitizing property deteriorate at low temperature and low humidity.

When the resin acid value of the resin (B) is less than 2.0, the dispersibility of the coating liquid, the surface strength and adhesiveness of the photoconductive layer, the image quality, particularly the image density at high temperature and high humidity, deteriorates. , 10.0, the sensitivity is slow, and the background stains and desensitizing property of the non-image area at high temperature and high humidity deteriorate. The weight ratio of the resin (A) and the resin (B) used in the present invention varies depending on the type, particle size and surface state of the inorganic photoconductor used, but generally the weight ratio of the resin (A) and the resin (B) is It is 8 to 3/2 to 7, and preferably 7 to 4/3 to 6.

When the image quality is important for the electrophotographic photoreceptor, the resin (A) is less than 50% by weight, and when the desensitization property is important for the electrophotographic lithographic printing plate, the resin (A) is used. More preferably, it is more than 50% by weight. As the inorganic photoconductor material used in the present invention, zinc oxide,
Titanium oxide, zinc sulfide, cadmium sulfide, cadmium carbonate, zinc selenide, cadmium selenide, tellurium selenide, lead sulfide and the like can be used, but zinc oxide and titanium oxide are preferable.

The total amount of the binder resin used for the inorganic photoconductor material is 10 to 100 parts by weight of the photoconductor.
It is used in a proportion of 50 parts by weight, preferably 15 to 30 parts by weight. In the present invention, various dyes can be used in combination as a spectral sensitizer, if necessary, for example, a carbonium dye, a diphenylmethane dye, a triphenylmethane dye,
Examples thereof include xanthene dyes, phthalein dyes, polymethine dyes (oxonol, merocyanine dyes, cyanine dyes, rhodacyanine dyes, styryl dyes, etc.), phthalocyanine dyes (which may contain metal).

The photoconductive layer of the present invention is excellent in that the performance thereof is hardly changed by the sensitizing dye even when the sensitizing dye as described above is used in combination. If necessary in the photoconductive layer of the present invention,
Various known additives for electrophotographic photoconductive layers such as chemical sensitizers can be used in combination, for example, electron-accepting compounds (halogen, benzoquinone, cranyl, acid anhydride, organic carboxylic acid, etc.),
Examples thereof include polyarylalkane compounds, hindered phenol compounds and p-phenylenediamine compounds.

The addition amount of these various additives is not particularly limited, but usually 0.001 to 2.0 with respect to 100 parts by weight of the photoconductor.
Parts by weight. The coating amount of the photoconductive layer 5 to 50 g / m ^2, preferably in particular 10~35g / m ^2, Mataatsu of the 3～50Myu, particularly 5~30μ is preferred. The photoconductive layer according to the present invention can be provided on a conventionally known conductive support.

As the conductive support, for example, metal such as aluminum, paper, plastic sheet and the like and their bonding, those obtained by conducting the conductive treatment by impregnating the base material of the composite with a low resistance substance, and the base material The back surface (the surface opposite to the surface on which the photoconductive layer is provided) is provided with conductivity, and at least one or more layers are coated for the purpose of moisture resistance and curl prevention, and a water resistant coating layer is formed on the surface of the support. Those provided, those in which at least one precoat layer is provided on the surface layer of the support layer as required, those obtained by laminating paper on a plastic which is a vapor-deposited substrate such as A1 can be used. ..

[0029]

EXAMPLES Examples of the present invention will be illustrated below, but the contents of the present invention are not limited thereto. Synthesis Example of Resin (A) 1: A-1 56 parts by weight of methyl methacrylate n-butyl methacrylate 36 〃 Haliftar 309-60 8 〃 (Harima Chemical Industry Co., Ltd., middle oil type alkyd resin, nonvolatile content 60 %) Toluene 100 〃 add an appropriate amount of initiator and solution polymerization, and the resin solution obtained by adding 37 parts toluene and 10 parts isopropyl alcohol is transparent, solid content 40%, resin acid value (Note 1) 1 It was 0.0.

Note 1) Acid value of resin: The resin is dissolved in a mixed solution of alcohol and toluene, and is expressed in mg of potassium hydroxide required to neutralize the acid contained in 1 g of a sample using phenolphthalein as an indicator. It was done. Synthesis Example 2 of Resin (A): A-2 30 parts by weight of methyl methacrylate 30 parts by weight of n-butyl methacrylate 20 〃 Haliftar 309-60 84 〃 Toluene 100 〃 An appropriate amount of an initiator was added to carry out solution polymerization and 6 parts of toluene. The resin solution obtained by adding 10 parts of isopropyl alcohol was transparent and had a solid content of 40% and a resin acid value of 1.8. Resin (A) Synthesis Example 3: A-3 Methyl methacrylate 58 parts by weight n-butyl methacrylate 40 〃 Haliftar 309-60 4 〃 Toluene 100 〃 An appropriate amount of an initiator is added and solution polymerized, and toluene 38 parts The resin solution obtained by adding 10 parts of isopropyl alcohol was transparent and had a solid content of 40% and a resin acid value of 0.8. Synthesis Example 4 of Resin (A): A-4 Methyl methacrylate 50 parts by weight 2-Ethylhexyl acrylate 30 〃 Hariftar LOG42-60X 33 〃 (Harima Chemical Industry Co., Ltd., short oil type alkyd resin, nonvolatile content 60 %) Toluene 100 〃 added an appropriate amount of initiator and solution polymerization, 27 parts toluene and 10 parts isopropyl alcohol were added to obtain a resin solution which was transparent and had a solid content of 40% and a resin acid value of 1.1. It was Synthesis Example 5 of Resin (A): A-5 Methyl methacrylate 50 parts by weight 2-Ethylhexyl acrylate 30 〃 Haliftar KL-912 33 〃 (Harima Chemical Industry Co., Ltd., long oil type alkyd resin, nonvolatile content 60 %) Acrylic acid 1 〃 Toluene 100 〃 Add an appropriate amount of an initiator to solution polymerization, and add 27 parts of toluene and 10 parts of isopropyl alcohol to obtain a resin solution which is transparent and has a solid content of 40% and a resin acid value of 3%. It was .4. Synthesis Example 6 of Resin (A): A-6 Methyl methacrylate 20 parts by weight n-Butyl methacrylate 20 〃 Haliftar 309-60 100 〃 Toluene 100 〃 An appropriate amount of an initiator is added to carry out solution polymerization and isopropyl alcohol 10 The resin solution obtained by adding the parts was transparent and had a solid content of 40% and a resin acid value of 1.9. Synthesis Example 7 of Resin (A): A-7 57 parts by weight of methyl methacrylate n-butyl methacrylate 40 〃 Haliftar 309-60 3 〃 100 〃 Toluene 39 〃 Department,
The resin solution obtained by adding 10 parts of isopropyl alcohol was transparent and had a solid content of 40% and a resin acid value of 1.9. Synthesis Example of Resin (B) 1: B-1 Methyl methacrylate 56 parts by weight n-Butyl methacrylate 36 〃 Acrylic acid 8 〃 Toluene 100 〃 An appropriate amount of an initiator is added to a resin solution obtained by solution polymerization. Was transparent and had a solid content of 50% and a resin acid value of 6.0. Synthesis Example 2 of Resin (B): B-2 Methyl methacrylate 58 parts by weight Ethyl acrylate 38 〃 Acrylic acid 4 〃 Toluene 100 〃 An appropriate amount of an initiator was added to the solution to obtain a resin solution, which was transparent. The solid content was 50% and the resin acid value was 2.5. Synthesis Example 3 of Resin (B): B-3 2-Ethylhexyl Methacrylate 52 parts by weight Ethyl acrylate 33 〃 Acrylic acid 15 〃 Toluene 100 〃 It was transparent and had a solid content of 50% and a resin acid value of 9.7. Synthesis Example 4 of Resin (B): B-4 Methyl methacrylate 60 parts by weight n-butyl methacrylate 40 〃 Toluene 100 〃 An appropriate amount of an initiator was added and solution polymerization was performed to obtain a resin solution which was transparent. The solid content was 50%, and the resin acid value was 0.6. Synthesis Example 5 of Resin (B): B-5 45 parts by weight of methyl methacrylate 45 parts by weight of ethyl acrylate 35 〃 acrylic acid 20 〃 toluene 100 〃 Yes, the solid content was 50% and the resin acid value was 12.5. Examples 1 to 7 and Comparative Examples A to F Example 1 (resin solid content weight ratio A-1 / B-1 = 5/5) Resin A-1 25 parts by weight produced in Synthesis Example 1 of resin (A) , A mixture of resin B-1 20 〃 prepared in Synthesis Example 1 of resin (B), photoconductive zinc oxide 100 〃, rose bengal (2% methanol solution) 5 〃, toluene 100 〃 in a ball mill for 2 hours. Dispersed to prepare a coating for the photoconductive layer, and electrophotographically treated electrophotographic base paper (with water resistance for lithographic printing plates), the dry adhesion amount
Apply with a wire bar to achieve 20g / m ² and 100 ℃
For 1 minute, then in the dark at 20 ℃ 60% RH for 24 hours.
An electrophotographic photosensitive paper was prepared by leaving it for a while. Example 2 (resin solid content weight ratio A-2 / B-2 = 5/5) In Example 1, instead of resin A-1, resin A-2,
An electrophotographic photosensitive paper was prepared in the same manner as in Example 1 except that Resin B-2 was used instead of Resin B-1. Example 3 (resin solid content weight ratio A-3 / B-3 = 5/5) In Example 1, instead of resin A-1, resin A-3,
An electrophotographic photosensitive paper was prepared in the same manner as in Example 1 except that Resin B-3 was used instead of Resin B-1. Example 4 (resin solid content weight ratio A-4 / B-1 = 5/5) The same operation as in Example 1 except that Resin A-4 was used instead of Resin A-1. Then, an electrophotographic photosensitive paper was prepared. Example 5 (resin solid content weight ratio A-5 / B-1 = 5/5) The same operation as in Example 1 except that Resin A-5 was used instead of Resin A-1. Then, an electrophotographic photosensitive paper was prepared. Example 6 (resin solid content weight ratio A-1 / B-1 = 8/2) In Example 1, the compounding amount of the resin A-1 was 40 parts by weight, and the compounding amount of the resin B-1 was 8 parts by weight. Example 1 except for changes
An electrophotographic photosensitive paper was prepared in the same manner as in. Example 7 (resin solid content weight ratio A-1 / B-1 = 3/7) In Example 1, the compounding amount of the resin A-1 was 15 parts by weight, and the compounding amount of the resin B-1 was 28 parts by weight. Example 1 except for changes
An electrophotographic photosensitive paper was prepared in the same manner as in. Comparative Example A (Resin A-1 simple substance) The same operation as in Example 1 was carried out except that in Example 1, only 50 parts by weight of Resin A-1 was used instead of Resin A-1 and Resin B-1. An electrophotographic photosensitive paper was prepared. Comparative Example B (resin solid content weight ratio A-1 / B-1 = 9/1) In Example 1, the compounding amount of the resin A-1 was 45 parts by weight, and the compounding amount of the resin B-1 was 4 parts by weight. Example 1 except for changes
An electrophotographic photosensitive paper was prepared in the same manner as in. Comparative Example C (Resin B-1 Alone) The same operation as in Example 1 was carried out except that in Example 1, only 40 parts by weight of Resin B-1 was used instead of Resin A-1 and Resin B-1. An electrophotographic photosensitive paper was prepared. Comparative Example D (resin solid content weight ratio A-1 / B-1 = 2/8) In Example 1, the amount of the resin A-1 was 10 parts by weight, and the amount of the resin B-1 was 32 parts by weight. Example 1 except for changes
An electrophotographic photosensitive paper was prepared in the same manner as in. Comparative Example E (resin solid content weight ratio A-6 / B-1 = 5/5) The same operation as in Example 1 except that Resin A-6 was used in place of Resin A-1. Then, an electrophotographic photosensitive paper was prepared. Comparative Example F (resin solid content weight ratio A-7 / B-1 = 5/5) The same operation as in Example 1 except that Resin A-7 was used in place of Resin A-1. Then, an electrophotographic photosensitive paper was prepared. Comparative Example G (resin solid content weight ratio A-1 / B-4 = 5/5) The same operation as in Example 1 except that Resin B-4 was used instead of Resin B-1. Then, an electrophotographic photosensitive paper was prepared. Comparative Example H (resin solid content weight ratio A-1 / B-5 = 5/5) The same operation as in Example 1 except that Resin B-5 was used instead of Resin B-1. Then, an electrophotographic photosensitive paper was prepared.

The image quality of these electrophotographic photosensitive papers was examined by changing the environment at the time of imaging, and the results are shown in Table 1. Further, the surface smoothness, electrical characteristics, printability when used with a lithographic printing plate, and printing durability were examined and shown in Table 2.

[0032]

[Table 1]

[0033]

[Table 2]

Note 2) Imageability: The obtained electrophotographic photosensitive paper is left for one day under each environmental condition, and then the plate-making machine AP-
10EX, developer AP-10 set (both are Iwasaki Tsushinki Co., Ltd.)
Image pickup, development, and fixing were performed. Note 3) Sensitivity: An exposure scale that gives the best image on electrophotographic photosensitive paper. The smaller the value, the faster the sensitivity. Note 4) Image density: The maximum value measured by a Macbeth reflection densitometer (Model RD-514 manufactured by Macbeth Co., USA) in the solid part of the imaged image, and the higher the value, the higher the image density. Note 5) Background stain on non-image area: The background stain on the non-image area of the captured image was visually evaluated.

The evaluation criteria are good, good, bad, and bad. Note 6) Smoothness: A value obtained by measuring the smoothness of the obtained electrophotographic photosensitive paper surface using a Beck's smoothness tester (manufactured by Kumagai Riki Kogyo Co., Ltd.) under the condition of an air capacity of 10 cc. The higher the value, the higher the smoothness.

In the case of the photoconductive layer using zinc oxide of the example, the smoothness of 50 to 200 sec is appropriate, and if it is less than 50 sec, agglomerates are likely to exist, and if it exceeds 200 sec, indentations are likely to occur. Note 7) Electrical characteristics: In a dark room of 20% and 60% RH, using an electrostatic charging tester (EPA-8100 type manufactured by Kawaguchi Electric Mfg. Co., Ltd.) for 5 seconds after corona discharge at -6 kv for 5 seconds. Leave it alone
The surface potential (charge amount) at this time was measured. Then, the potential V60 after standing still in the dark for 60 seconds was measured, and the potential retention after dark decay for 55 seconds, that is, the dark decay retention rate was calculated by (V60 / V5) × 100 (%) It was Note 8) Printability: Plate-making under the same conditions as 20% and 60% RH of Note 2), desensitizing solution V etchant (Iwasaki Tsushinki Co., Ltd.)
Is used to perform desensitization treatment by hand etching and one pass through an etching processor (manufactured by Ricoh Co., Ltd.), which is then printed as a lithographic printing plate on a printing machine (Besty-4700CD type manufactured by Tokyo Aviation Keiki Co., Ltd.). Then, the background stains (including stains due to impressions) on the non-image portion of the printed matter were visually evaluated.

The evaluation criteria are good, good, bad, and bad. Note 9) Printing durability: 7,000 sheets are printed under the same conditions as the hand etching process of Note 8), and the number of printable sheets is shown without any problems in the image quality of the image area. Is good.

As shown in Table 1, the electrophotographic photosensitive member of the present invention had good image density of the picked-up image, good background stain on the non-image area, and good stability against environmental changes. Furthermore, as shown in Table 2, the smoothness of the surface of the photoconductive layer and the electrical characteristics are good,
As a lithographic printing plate, even when subjected to desensitizing treatment by hand etching or passing through an etching processor once, no background stain was observed on the printed matter and the printing durability was good.

Comparative Example A using only the resin (A) of the present invention
Has a high image density, but the non-image area is inferior in the background stain, and the image quality at high temperature and high humidity is particularly poor. Furthermore, the smoothness of the photoconductive layer is high, and the film strength and adhesiveness are weak. The printed matter was stained by the impression, and the photoconductive layer was peeled off during printing.
Comparative Example B, in which the solid content weight ratio of the resin (A) of the present invention is high, has higher performance than Comparative Example A,
The image quality at high temperature and high humidity, the smoothness of the photoconductive layer, the film strength, the adhesiveness, the stains on the imaged material and the printed material due to the impression, and the peeling of the photoconductive layer during printing are still insufficient.

Comparative Example B using only the resin (B) of the present invention
Has good stability against environmental changes, but image density,
In particular, the stain on the printed matter is inferior. Resin (B) of the present invention
Comparative Example D, which has a higher solid content weight ratio, has higher performance than Comparative Example C, but is still insufficient in terms of image density and background stain of printed matter. Comparative Examples E and F in which the amount of the alkyd resin was increased or decreased compared to the resin (A) of the present invention deteriorated the background stain and the smoothness of the non-image part, and further increased in Comparative Example C, the image density, and the non-image at low temperature and low humidity. In Comparative Example D, in which the background stain in the image area was aggravated and reduced, the image properties and electrical characteristics at high temperature and high humidity were aggravated.

In Comparative Examples G and H in which the resin acid value was increased or decreased from the resin (B) of the present invention, the background stain, smoothness and printability of the non-image area were deteriorated, and in Comparative Example E which was further reduced, the high temperature and high temperature were obtained. The comparative example F, in which the image density when wet, the electrical characteristics were deteriorated, the photoconductive layer was peeled off during printing, and the increased image density, the background stains in the non-image area at high temperature and high humidity, and the printability were deteriorated. did. From the above,
Only when the binder resin of the present invention is used, an electrophotographic photoreceptor satisfying the image property, electrical property, printability, printing durability and smoothness of the photoconductive layer surface can be obtained.

[0042]

INDUSTRIAL APPLICABILITY According to the present invention, an electrophotographic photosensitive member has excellent image properties, electrical characteristics, and stability against environmental changes, and further has excellent printing durability as a lithographic printing plate and indentations such as scratches are imaged. With a surface smoothness that does not easily occur on printed matter and a processing method that uses a single pass through an etching processor that has a low treatment effect, it has excellent desensitizing reactivity that does not cause spot stains as well as uniform stains on the entire printed matter. It is possible to obtain an electrophotographic photoreceptor having a desensitized film forming performance.

Claims (1)

Claims: 1. An electrophotographic photosensitive member having a photoconductive layer mainly composed of an inorganic photoconductor and a binder resin formed on a conductive support, wherein the binder resin is: The electrophotographic photoreceptor containing the resin (A) and the resin (B) shown in (4) and having a solid content weight ratio of resin (A) / resin (B) = 8 to 3/2 to 7. .. Resin (A): A first resin composition obtained by polymerizing an acrylic monomer mixture in the presence of an alkyd resin, wherein the weight ratio of the alkyd resin to the acrylic monomer mixture is 2.5. Resins that are ~ 50 / 97.5-50. Resin (B): A second resin composition obtained by polymerizing an acrylic monomer mixture, and having a resin acid value of 2.0 to 10.0.