JPS63272551A - Original plate for lithographic press - Google Patents

Abstract

PURPOSE:To obtain an original plate for lithographic press having excellent desensitizing performance and casing no dot type scumming, by adding one kind of resin containing at least one kind of functional group having two hydroxyl groups arranged in cubically close position each other while being protected with a protective group, as main component of a surface layer. CONSTITUTION:A resin containing a specific functional group is a homo-polymer or multi-dimensional polymer where polymer component containing functional group occupies 40-10wt.%, and a resin containing at least one kind of functional group in such form as at least two hydroxyl groups located at cubically close positions are protected simultaneously with single protective group is decomposed by desensitizing liquid and wetting water being employed during printing through hydrolysis or hydrogenolysis to produce at least two hydroxyl groups. Consequently, in an original plate for lithographic press containing resin is main component in the surface layer, non-image portion is made hydrophilic by the hydroxyl group produced in the resin and discriminated clearly from lipophilic image portion, thus preventing adhesion of ink to the non-image portion during printing.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an electrophotographic printing original plate made by an electrophotographic method, and in particular, a surface layer having specific properties on a photoconductive layer. This invention relates to a lithographic printing original plate which is provided with a lithographic printing plate.

(Prior art and its problems) Currently, various types of offset original plates for direct plate making have been proposed and put into practical use. A photoreceptor provided with a photoconductive layer mainly composed of resin is subjected to a normal electrophotographic process to form a highly lipophilic toner image on the surface of the photoreceptor, and then the surface is desensitized with an etchant. A widely used technique is to obtain an offset original plate by selectively making non-image areas hydrophilic by treatment with a liquid.

In order to obtain good printed matter, first, the original image is faithfully copied onto the offset master plate, the surface of the photoreceptor is easily compatible with the anti-fat treatment liquid, and the non-image area is made sufficiently hydrophilic, and at the same time it has water resistance. In addition, during printing, the photoconductive layer with the image does not separate and is compatible with dampening water,
It is necessary to have performance such as maintaining sufficient hydrophilicity in non-image areas so that stains do not occur even if the number of printed sheets increases.

In particular, as an offset master plate, background smearing due to insufficient desensitization is a major problem, and in order to improve this problem, various studies are being conducted on the development of zinc oxide binding resins that improve desensitization. , for example, Special Publication No. 50-3101
No. 1, JP-A-53-54027, JP-A-547207
No. 35, JP-A-57-202544, JP-A-58-6
It is disclosed in the specification of No. 8046 and the like. However, even if these resins are said to be effective in improving the anti-grease property, when actually evaluated, they are still unsatisfactory in terms of scumming and printing durability.

On the other hand, using an organic photoconductive compound as the photoconductive particle,
It is also possible to use an electrophotographic body in which a photoconductive layer and a binder resin are provided on a grained aluminum substrate.

To make this type of master plate, as described above, a toner image is formed on the photosensitive layer by a normal electrophotographic method, and then the non-image area is dissolved and removed using a processing liquid. As a result, the non-image portion becomes an aluminum substrate and becomes hydrophilic. For example, Special Publication No. 37-17162, Special Publication No. 17162, Special Publication No. 17162
-39405, JP-A-52-2437, JP-A-56
When using a photosensitive layer in which an oxadiazole compound or an oxazole compound is bound with an alkali-soluble resin such as a styrene-maleic anhydride copolymer, as shown in Japanese Patent Application Laid-open No. 105254-10724, etc.
No., JP-A-55-16125, JP-A-58-1509
It is known that a photosensitive layer comprising a phthalocyanine pigment or an azo pigment and an alkali-soluble phenol resin is used, as shown in Japanese Patent Application Laid-Open No. 58-162961.

However, in this plate-making process, the photosensitive layer in the non-image area must be dissolved and removed, which requires a large-scale apparatus, and this takes time, resulting in a slow plate-making speed. Furthermore, since ethylene glycol, glycerin, methanol, ethanol, etc. are used as processing liquids (organic solvents mentioned above), problems with this plate-making method remain in terms of cost, safety, pollution, and occupational health. has been done.

Furthermore, Japanese Patent Publication No. 45-5666 discloses a method of preparing a printing plate of a hydrophilic treatment type on the surface of a non-image area, which is easy to make by providing a specific resin layer on an ordinary electrophotographic photoreceptor. That is, vinyl ether is deposited on the electrophotographic photosensitive layer.
A printing plate provided with a surface layer comprising a maleic anhydride copolymer and a hydrophobic resin compatible therewith is disclosed.

This layer is N (hydrophilizable layer) that can be made hydrophilic by treating the non-image area with an alkali to open the acid anhydride ring portion with water after the toner image is formed.

The vinyl ether-maleic anhydride copolymer used there becomes water-soluble when ring-opened and made hydrophilic, so even if it is compatible with other hydrophilic resins, a layer may not be formed. Even if it were, its water resistance was extremely poor, and its printing life was limited to 500 to 600 sheets at most.

Furthermore, JP-A-60-90343, JP-A-60-159
No. 756, JP-A No. 61-217292, etc.,
A method of providing a surface layer (hydrophilicizable layer) containing silylated polyvinyl alcohol as a main component and also using a crosslinking agent is disclosed.

That is, in this layer, silylated polyvinyl alcohol is hydrolyzed in a non-image area after toner image formation to make it hydrophilic. In addition, in order to maintain the film strength after hydrophilization, the degree of silylation of polyvinyl alcohol is adjusted, and the remaining hydroxyl groups are crosslinked using a crosslinking agent.

However, although it is stated that these methods improve the scumming resistance of printed matter and increase the number of printed sheets, actual evaluation shows that they are still unsatisfactory, especially in terms of scumming. In addition, silylated polyvinyl alcohol is produced by silylating polyvinyl alcohol in a desired proportion with a silylating agent, but since it is a polymer reaction,
Difficult to produce stably. In addition, since the chemical structure of the hydrophilic polymer is limited, we have to ensure 1) charging properties, 2) quality of copied images (halftone reproducibility/resolution of the image area, 3) It is difficult to prevent the surface layer from affecting the exposure sensitivity.

Furthermore, in order to obtain sufficient hydrophilicity after hydrolysis, a relatively large amount of silylated polyvinyl alcohol moiety is required, making it expensive, and furthermore, material composition is required to achieve a comprehensive balance of electrophotographic properties, film properties, etc. There were problems such as a narrow tolerance range.

The present invention is intended to improve the problems of electrophotographic lithographic printing original plates as described above.

The object of the present invention is to provide a lithographic printing plate with excellent anti-grease properties that reproduces a faithful copy image to the original image, and which does not cause not only uniform background smudges on the entire surface but also dotted smudges as an offset original plate. The purpose is to provide original printing plates.

Another object of the present invention is to maintain sufficient hydrophilicity in non-image areas and prevent background smudges even when the number of printed sheets increases.
The present invention provides a lithographic printing plate having high stiffness.

Another object of the present invention is to provide a lithographic printing original plate having a binder resin that can be made hydrophilic in non-image areas and is easy to manufacture.

Another object of the present invention is to provide a lithographic printing original plate which is relatively inexpensive and has a wide range of material composition tolerances in order to achieve a comprehensive balance of electrophotographic properties, film properties, etc.

(Means for Solving the Problems) The above-mentioned planographic printing utilizes an electrophotographic material comprising at least one photoconductive layer provided on a conductive support and a surface layer provided on the top layer. In the original plate, as the main component of the surface layer, a resin containing at least one functional group having at least two hydroxyl groups located sterically close to each other and simultaneously protected with one protecting group is used. This is achieved by an original plate for electrophotographic lithographic printing, which is characterized in that it contains one kind of material.

In the present invention, examples of functional groups having at least two hydroxyl groups in a protected form that are sterically close to each other include those represented by the following general formulas (1), (II), and (I[). can be mentioned.

General formula (1) c In formula (1), R,, R, may be the same or different from each other, and are a hydrogen atom, a hydrocarbon group, or -0-R'
(R' represents a hydrocarbon group), and Z represents a carbon-carbon bond which may be via a heteroatom (provided that the number of atoms between oxygen atoms is 5 or less). ] General formula (II) (In (II), Z is as defined above.) General formula (I[[) (In formula (III), R+, Rz and Z are as defined above. ) A more detailed explanation of the functional group is as follows.

In the above formula, R1 and Rz may be the same or different, and preferably represent a hydrogen atom, an optionally substituted alkyl group having 1 to 12 carbon atoms (e.g., methyl group, ethyl group, propyl group, butyl group). , bexyl group, 2-methoxyethyl group, octyl group, etc.), optionally substituted aralkyl groups having 7 to 9 carbon atoms (such as benzyl group, phenethyl group, methylbenzyl group, methoxybenzyl group, chlorobenzyl group, etc.) ), alicyclic groups having 5 to 7 carbon atoms (e.g., cyclopentyl group, cyclohexyl group, etc.), optionally substituted aryl groups (e.g., phenyl group, chlorophenyl group, methoxyphenyl group, methylphenyl group, cyanophenyl group) or -0-R'(R' is synonymous with the hydrocarbon group in R+ and Rz).

Z represents a carbon-carbon bond which may be via a heteroatom, and the number of atoms between oxygen atoms is 5 or less.

The resin that binds at least one functional group used in the present invention can be obtained by a method in which the hydroxyl groups contained in the polymer and located in positions sterically close to each other as described above are protected with a protecting group by a polymer reaction; Or, it is produced by a method of polymerizing a monomer containing at least two hydroxyl groups that has been previously protected with a protecting group, or by a polymerization reaction of the monomer and another monomer that can be copolymerized with it. Ru.

The former polymer reaction production method includes polymer components (i)-( ix) (R' is H or a substituent such as CH3, etc.) Ul-I Llti (-CH2-C-Y CH,CH,0H (Vl) +CHz CH-← CH,0H (X' represents a linking group) By reacting a polymer containing a carbonyl compound, an orthoester compound, a halogen-substituted formate, a dihalogen-substituted silyl, etc., a form in which at least two desired hydroxyl groups are simultaneously protected with one protecting group can be obtained. It is possible to form a functional group having .

Specifically, the Chemical Society of Japan, "New Experimental Chemistry Course Volume 14, Synthesis and Reactions of Organic Compounds (V), Page 2505 (published by Maruzen Co., Ltd.), J, F, W, Mc, 0m1e, r
Protective groups in Organ
ic Chea+1try J Chapters 3 and 4 (P
It can be produced by the method described in the known literature cited in the review such as ``Lenum'' (Published by Press). In the latter method, a monomer with at least two hydroxyl groups protected in advance is synthesized by a known method cited in the above-mentioned review, and then, if necessary, other monomers that can be copolymerized with the monomer are synthesized. A homopolymer or a multicomponent copolymer can be produced by polymerizing the polymer by a normal polymerization method in the coexistence of polymers.

Other monomers that can be copolymerized include, for example,
Aliphatic carboxylic acid vinyl or allyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, allyl acetate, allyl propionate, etc.; Saturated carboxylic acids, esters or amides of these unsaturated carboxylic acids, styrene, vinyltoluene, styrene derivatives such as α-methylstyrene, α-olefins, acrylonitrile, methachronitrile, N-
Examples include vinyl group-substituted heterocyclic compounds such as vinylpyrrolidone.

In order to further improve the strength of the surface layer, it is possible to utilize the crosslinking effect described below. , carboxyl group, hydroxyl group, etc.) is preferably copolymerized.

These methods are described, for example, in "New Experimental Chemistry Course Volume 14, Synthesis and Reactions of Organic Compounds (■)", Volume 253, published by the Chemical Society of Japan.
5 (published by Maruzen Co., Ltd.), Yoshio Iwakura: Keisuke Kurita, "Reactive Polymers", page 170 (published by Kodansha), etc., are described in detail in the known literature cited as a review.

The molecular weight of the resin of the present invention is 103 to 106, preferably 5
It is X103-10S.

In addition, the polymer component containing the functional group in the resin is 30 to 1
00% by weight, preferably 35 to 85% by weight.

More specifically, examples of polymer components containing the functional group include the following. However, the scope of the present invention is not limited to the following.

― CH.

CH,-.

OCR.

(12) -fcH2-CH-CH-CH1narchyCH2CH.

C2H5 Hs (15) Yun-CH2-C--Chi Hs (16) -(-CH, -c--Chi H, C0 (17) (CH,=C)I + CH.

-(-CH, -C-) The resin containing the specific functional group of the present invention is a homopolymer or a multicomponent copolymer consisting of 40 to 100% by weight of the polymer component containing the nuclear functional group. , preferably 40~
It is a multicomponent copolymer containing 80% by weight of this component.

Conventionally known resins can be used in combination with the resin used in the present invention. Examples include silicone resin, alkyd resin, vinyl acetate resin, polyester resin, styrene-butadiene resin, acrylic resin, etc. Specifically, Ryuji Kurita, Tsugube Niishiwatari, Kobunshi, Vol. 17, No. 27
8 (1968), Harumi Miyamoto, Hidehiko Takei, Imaging 1973 (Nα8), p. 9, cited in a review, etc. Known materials for the binder resin used in the photoconductive layer can be mentioned.

The resin used in the present invention and known resins can be mixed in any proportion, but the content of the specific functional group according to the present invention in the total resin amount is 40 to 100% by weight, preferably 45% by weight. % or more.

If the content of the nuclear functional group component is less than 40% by weight, the resulting lithographic printing original plate will not have sufficient hydrophilicity caused by desensitizing treatment with a desensitizing liquid or fountain solution, resulting in stains during printing. Occur.

The resin containing at least one functional group containing at least two hydroxyl groups located in sterically close positions to each other and simultaneously protected with one protecting group according to the present invention includes:
It is a resin that is hydrolyzed or hydrolyzed by a desensitizing liquid and a dampening solution used during printing to produce at least two hydroxyl groups.

Therefore, in the present lithographic printing original plate containing the resin as a main component in the surface layer (hydrophilizable layer), the non-image area is made hydrophilic by the hydroxyl groups generated in the resin, and the image area becomes lipophilic. It is clearly distinguishable and prevents printing ink from adhering to non-image areas during printing.

Furthermore, the copolymerized component in the resin of the present invention decomposes,
Since at least two hydroxyl groups are generated, sufficiently high hydrophilicity can be exhibited even if the content of the core copolymer is small, and the effects of the present invention can be effectively achieved. Therefore, it can be obtained at a relatively low cost, and the tolerance range for the composition of the material when achieving a comprehensive balance of electrophotographic properties, film properties, etc. is widened.

In order to improve the strength of the hydrophilic surface layer itself, the adhesion with the electrophotographic photosensitive layer, the electrophotographic properties, etc., resins other than the resins of the present invention described above may be added, or crosslinking agents or plasticizers may be added. May be added.

As the crosslinking agent, commonly used crosslinking agents such as organic peroxides, metal soaps, organic silanes, and polyurethanes, and curing agents such as epoxy resins can be used. Specifically, they are described in "Crosslinking Agent Handbook" edited by Fuzo Yamashita and Tosuke Kaneko, published by Taiseisha (1981).

Furthermore, the surface layer that can be made hydrophilic may have its surface mechanically matted or layered for the purpose of improving development characteristics during toner development, adhesion of toner images, or water retention after hydrophilic treatment. may contain a matting agent. Examples of the matting agent include fillers such as silicon dioxide, zinc oxide, titanium oxide, zirconium oxide, glass particles, alumina, and gray, and polymer particles such as polymethyl methacrylate, polystyrene, and phenol resin.

What is important when forming the surface layer is that the non-image area becomes sufficiently hydrophilic after the desensitization treatment, as described above.

That is, this hydrophilicity can be confirmed, for example, by measuring the contact angle with respect to water.

The contact angle with water on the surface of the surface layer (hydrophilic layer) before desensitization is approximately 60°C to 120°C, but after desensitization, it decreases to approximately 50 to 20°C. and become very wet with water. Therefore, the printing plate has an image area made of lipophilic toner and a highly hydrophilic non-image area formed on its surface. Therefore,
The contact angle of the surface layer with water after the anti-fat treatment may be 20 degrees or less.

The present invention is particularly superior in that its hydrophilicity is even better than conventional ones.

The electrophotographic photosensitive layer (photoconductive N) used in the present invention includes:
Any photoconductive substance can be used, whether it is an inorganic photoconductive compound or an organic photoconductive compound.

Examples of inorganic photoconductive substances include zinc oxide, titanium oxide, zinc sulfide, selenium, selenium alloys, cadmium sulfide, cadmium selenide, and silicon, which together with the binding resin form the photoconductive layer. You can also
Alternatively, the photoconductive layer may be formed alone by vapor deposition, sputtering, or the like. As an organic photoconductive substance,
For example, as polymers, the following (1) to (5) can be mentioned.

(1) Polyvinylcarbazole and its derivatives described in Japanese Patent Publication No. 34-10966, (2) Japanese Patent Publication No. 43-1
Polyvinylpyrene, polyvinylanthracene, poly-2 described in JP-A No. 8674 and Japanese Patent Publication No. 43-19192
-vinyl-4-(4"-dimethylaminophenyl)-5
-vinyl polymers such as phenyl-oxazole and poly-3-vinyl-N-ethylcarbazole; (3) polyacenaphthylene, polyindene, and copolymers of acenaphthylene and styrene described in Japanese Patent Publication No. 19193-1973; Polymer.

(4) Condensation resins such as pyrene-formaldehyde resin, brompyrene-formaldehyde resin, and ethylcarbazole-formaldehyde resin described in Japanese Patent Publication No. 56-13940, etc. (5) JP-A-56-90833 and 56-16155
Various triphenylmethane polymers described in Publication No. 0.

Examples of low molecular weight compounds include the following (6) to (18).

(6) Triazole derivatives described in US Pat. No. 3,112,197, etc.; (7) Oxadiazole derivatives, described in US Pat. No. 3,189,447, etc.;
Imidazole derivatives described in Publication No. 16096, etc. (9) U.S. Patent No. 3615402, U.S. Patent No. 382098
No. 9, No. 3542544, Special Publication No. 45-555, No. 10983-1983, Japanese Patent Publication No. 93224-1971,
JP-A-55-17105, JP-A-56-4148,
JP-A-55-108667, JP-A-55-15695
No. 3, polyaryl alkane derivatives described in JP-A-56-36656, publications, etc. (10) U.S. Pat. No. 3180729, U.S. Pat. No. 42787
No. 46, JP-A-55-88064, JP-A-55-88
No. 065, JP-A-49-105537, JP-A-55-
No. 51086, JP-A-56-80051, JP-A-56
-88141, JP-A-57-45545, JP-A-5
Pyrazoline derivatives and pyrazolone derivatives described in No. 4-112637, JP-A-55-74546, publications, etc.

(11) U.S. Patent No. 3,615,404, Japanese Patent Publication No. 5
1-10105, JP-A-54-83435, JP-A-54-110836, JP-A-54-119925,
Phenyldiamine derivatives described in Japanese Patent Publication No. 46-3712, Japanese Patent Publication No. 47-28336, publications, etc. (12) U.S. Patent No. 3567450, Japanese Patent Publication No. 49-3
No. 5702, West German Patent (DAS) No. 1110518,
U.S. Patent No. 3180703, U.S. Patent No. 324059
No. 7, U.S. Patent No. 3,658,520, U.S. Patent No. 423
No. 2103, U.S. Patent No. 4175961, U.S. Patent No. 4012376, JP 55-144250, JP 55-119132, JP 39-27577,
Arylamine derivatives described in JP-A-56-22437, publications, etc., (13) amino-substituted chalcone derivatives described in U.S. Pat. No. 3,526,501, (14) U.S. Pat. No. 3,542,546, etc. (15) Oxazole derivatives described in US Pat. No. 3,257,203, etc.; (16) Styryl anthracene derivatives described in JP-A-56-46234, etc.; (17) JP-A-56-46234, etc.; Fluorenone derivatives described in Publication No. 54-110837 etc., (18) U.S. Patent No. 3717462, JP-A-54-5
9143 (corresponding to U.S. Patent No. 415098), JP 55-52063, JP 55-52064, JP 55-46760, JP 55-85495, JP 57-11350 No., Japanese Patent Publication No. 57-14874
Vidrazone derivatives disclosed in Patent No. 9, Publication No. 1, etc.

Two or more of these photoconductive substances may be used in combination depending on the case.

Among these photoconductive materials are poly-N-vinylcarbazole; triarylazines such as tri-P-)lylamine and triphenylamine; 4,4″-bis(diethylamine)-2°2′-dimethyltri polyarylmethanes such as phenylmethane; and 3-(4
-dimethylaminophenyl)-1,5-diphenyl-2
-Unsaturated heterocycle-containing compounds represented by pyrazoline derivatives such as pyrazoline are preferably used.

As the binder that can be combined, all conventionally known binders can be used. Typical examples include vinyl chloride-vinyl acetate copolymer, styrene-butadiene copolymer, styrene-butyl methacrylate copolymer, polymethacrylate, polyacrylate, polyvinyl acetate, polyvinyl butyral, alkyd resin, silicone resin, and epoxy resin. , epoxy ester resin, polyester resin, etc.

It is also possible to combine it with an aqueous acrylic emulsion or an acrylic ester emulsion.

For examples of specific polymeric materials useful as binders, see
Research Disclosure
Disclosure), Vol. 109, pp. 61-67.
under the title ``Electrophotographic Elements, Materials and Methods''.

Generally, the amount of binder present in the photoconductive compositions of the present invention can vary. Typically useful amounts of binder are:
For the total amount of photoconductive material and binder mixture, about 10
and about 90% by weight.

Furthermore, conventionally known compounds can be added as spectral sensitizers. For example, xanthine dyes, triphenylmethane dyes, azine dyes, phthalocyanine dyes (
Examples include metal-containing), polymethine dyes, etc. Specifically, examples include Harumi Miyamoto and Hidehiko Takei, Imaging 1973 (Nα
8), 2, “Recording material and photosensitive resin JC, J, You
ng, R, C, A Reviei 1, 5,469 (
1954) Wataru Kiyota, Transactions of the Institute of Electrical Communication Engineers J63-C (Nα2)
, 97 (1980) Yuji Harasaki et al. Industrial Chemistry Journal, 1dan, 78 and 188 Tadaaki Tani, Journal of the Photographic Society of Japan, 35.20B (1972), Re5earch, Disclosure, 1982
216, pp. 117-118, Comprehensive technical data collection "Recent development and practical application of photoconductive materials and photoreceptors" Nihon Kagaku Information ■Publishing department series (1986), etc. Publicly known materials cited in the review.

The photoconductive layer may be formed from a single layer, or may be formed from multiple layers of two or more layers.

In the case of a multilayer structure, for example, a charge generating layer consisting of the vapor-deposited photoconductor described above or an organic chain such as a phthalocyanine pigment or an azo pigment and a binding resin added as necessary;
A so-called resin-separated type photoconductive layer may be considered, which is laminated with a charge transport layer made of the above-mentioned high-molecular compound, low-molecular compound, and binding resin.

The photoconductive layer used in the present invention can be provided on a commonly used and known support. Generally speaking, the support of the electrophotographic photosensitive layer is preferably electrically conductive, and examples of the electrically conductive support include metal, paper, etc.
A substrate such as a plastic sheet that has been treated to conductivity by impregnating it with a low-resistance substance, etc. The purpose is to impart conductivity to the back side of the substrate (the side opposite to the side on which the photosensitive layer is provided) and to prevent curling. A1 coated with at least one layer of A1 A material made by laminating a plastic substrate onto paper, etc., can be used.

Specifically, examples of conductive substrates or conductive materials include:
Yukio Sakamoto, Electrophotography 14, (Nα1), pp. 2-11 (
1975L Hiroyuki Moriga "Introductory Chemistry of Special Papers" Kobunshi Publishing Association (1975L M, F.

Hoover, J., Macromol, Sci., C.
hem, A-4(6), pp. 1327-1417 (19
70) etc. can be used.

The coating thickness of the photoconductive composition on a suitable support can vary widely. Usually about 10 microns to about 300 microns
It can be applied within the range of microns (before drying). A preferred range of coating thickness before drying has been found to be within the range of about 50 microns to about 150 microns. However, useful results can be obtained even outside this range. The dry thickness of this coating may range from about 1 micron to about 50 microns.

The thickness of the hydrophilic surface layer of the present invention is 10 μm or less, particularly 0.1 to 5 μm for Carlson process.
It is preferable that

If it is thicker than 5 μm, disadvantages may occur such as a decrease in sensitivity of the lithographic printing original plate as an electrophotographic photoreceptor and an increase in residual potential.

In order to actually make the lithographic printing original plate of the present invention, generally,
First, an electrophotographic photosensitive layer (photoconductive layer) is formed on a conductive support according to a conventional method.Next, on this layer, the resin of the present invention and, if necessary, the additives mentioned above are added to a boiling point of 20.
It can be produced by dissolving or dispersing it in a volatile hydrocarbon solvent at 0°C or lower, coating it, and drying it. Specifically, preferred organic solvents are halogenated hydrocarbons having 1 to 3 carbon atoms, such as dichloroethane, chloroform, 1,2-dichloroethane, tetrachloroethane, dichloropropane, and trichloroethane. Other various solvents used in coating compositions, such as aromatic hydrocarbons such as chlorobenzene, toluene, xylene or benzene, ketones such as acetone or 2-butanone, ethers such as tetrahydrofuran, and methylene chloride, and the above-mentioned solvents. Mixtures of can also be used.

A toner image is formed on the original plate obtained as described above in accordance with a conventional electrophotographic method. A printing plate can be obtained by treating this with a fat-free treatment liquid (for example, an acidic or alkaline aqueous solution or an aqueous solution containing a reducing agent) to make the non-image area hydrophilic.

In addition to the above-mentioned normal electrophotographic method, methods for forming toner images include, for example, (a) electrostatic transfer of an electrostatic latent image formed on another electrophotographic photoreceptor and development thereof. How to get toner images. (b) A method of applying an electric signal to a multi-needle electrode to form an electrostatic latent image according to the electric signal and developing it to obtain a toner image. (c) Special Publication No. 45-30320,
An electrostatic latent image is formed on a screen-shaped electrophotographic photoreceptor having a large number of minute openings, as described in Japanese Patent Publication No. 4B-5063, Japanese Patent Application Laid-open No. 51-341, etc.
By performing corona charging processing via this electrostatic latent image, the ion flow of the corona is modulated and an electrostatic latent image is created.
There is a method of developing this to obtain a toner image. In this case as well, the hydrophilic layer of the present invention can be applied, and a lithographic printing original plate in which a hydrophilic layer is directly provided on a conductive support may be used.

In this way, if the hydrophilic layer of the present invention is used,
Any conventionally known electrophotographic photoreceptor can be used as a high-quality lithographic printing original plate.

The hydrophilizable layer is a film that exhibits both high hydrophilicity and water resistance after hydrophilic treatment, and also has extremely good adhesion to the base plate and the torch image. Therefore, the obtained lithographic printing original plate is The occurrence of scumming is extremely suppressed, and it has high printing durability.

Furthermore, since the printing plate of the present invention can maintain almost the original sensitivity of the electrophotographic photosensitive layer, it is possible to obtain a printing original plate with significantly higher sensitivity than conventional printing original plates for electrophotographic engraving. In addition, conventionally, a single layer must have the properties of photoconductivity and hydrophilicity, so
Previously, only limited materials such as zinc oxide could be used, but in the printing original plate of the present invention, the functions are separated into a photoconductive layer and a hydrophilizable layer, so the range of selection of the photoconductive layer is expanded, and therefore, for example, By selecting a material that is highly sensitive to long wavelength light, it becomes possible to write with H, -N, laser, or semiconductor laser, which was previously impossible.

In addition, in the printing original plate of the present invention, the non-image area can be made hydrophilic by simply immersing it in a hydrophilic treatment solution for a few seconds, so it is small and
Plate making becomes possible with a simple device.

(Example) Examples of the present invention are illustrated below, but the content of the present invention is not limited thereto.

Example 1 25 g of 4,4'-bis(diethylamino)-2,2'-dimethyltriphenylmeth as an organic photoconductive substance
1-bisphenol A polycarbonate (manufactured by GE,
Product name Lexan 121) 5g.

Spectral sensitizing dye (A) of the following structural formula 40 cm, 0.2 g of an anilide compound of the following structural formula (B) as a chemical sensitizer, methylene chloride 30 mft and ethylene chloride 3
It was dissolved in 0 mA' to prepare a photosensitive solution.

(Spectral sensitizing dye (A)) Shi4M5(j)
4F1m(t) (anilide compound (B)) This photosensitive solution was applied to a conductive transparent support (a 100 μm polyethylene terephthalate support with a surface resistance 1
03Ω) to obtain an organic thin film having a photosensitive layer of about 4μ.

On the other hand, n-butyl methacrylate 30g1 specific example (15
) A mixed solution of 20 g of monomer corresponding to the copolymerization component shown in ) and 200 g of toluene was heated at a temperature of 70°C under a nitrogen stream.
After heating to , asobisisobutyronitrile (AIBN
) 1.0 g was added and reacted for 8 hours. The weight average molecular weight of the obtained copolymer was 43,000.

A 5% by weight toluene solution of the obtained copolymer was applied to the surface of the electrophotographic photoreceptor obtained previously using a doctor blade to form a surface layer of about 2 μm. The photosensitive material was passed once through an etching processor using a desensitizing liquid (ELP-EX, manufactured by Fuji Photo Film ■) to be desensitized.

A droplet of 2 μl of distilled water was placed on this, and the contact angle with the water formed was measured with a goniometer and found to be 18°. The contact angle before the desensitization treatment was 85°, clearly indicating that the surface layer of the photosensitive material was very well rendered hydrophilic.

The original plate obtained in this way was processed using a fully automatic plate making machine ELP404V (Fuji Photo Film ■) using a negatively charged liquid developer.
A toner image is formed by making a plate using an offset printing machine (HAF DASTER 800 manufactured by HAMADASTAR ■), which is treated to make it unfattenable under the same conditions as above, and then used as an offset master.
3X type) and printed on high-quality paper.

The number of prints that could be printed without causing problems with scumming in the non-image areas and image quality in the image areas was 10,000.

Example 2 5 g of bisazo pigment with the following structural formula, 9 g of tetrahydrofuran
A mixture of 5 g of polyvinyl butyral resin (manufactured by Denki Kagaku Kogyo Co., Ltd.: Denka Butyral #4000-1) of 30 g of a 5% by weight tetrahydrofuran solution was sufficiently ground in a ball mill.Then, this mixture was taken out, and 520 g of tetrahydrofuran was added thereto while stirring. Ta. This dispersion was prepared in Example 1 using a wire round rod. A charge generation layer of about 0.7 gm was formed by coating on the conductive transparent support used in .

(Bisazo pigment) <Next, 20 g of a hydrazone compound having the following structural formula, 20 g of polycarbonate resin (manufactured by GE, trade name: Lexan 121)
A mixed solution of 160 g of tetrahydrofuran and 160 g of tetrahydrofuran was coated on the charge generation layer using a wire round rod to form a charge transport layer of about 18 μm, thereby obtaining an electrophotographic photoreceptor having a photosensitive layer consisting of two layers.

(Hydrazone compound) On the other hand, a mixed solution of 20 g of benzyl methacrylate, 30 g of ethyl methacrylate, 50 g of a monomer corresponding to the copolymer component shown in Example (25), and 300 g of toluene was heated to a temperature of 75°C under a nitrogen stream. After heating, A.1.
1.0 g of B and N were added and reacted for 8 hours.

The weight average molecular weight of the obtained copolymer was 45,000.

A 5% by weight toluene solution of the obtained copolymer was applied onto the photosensitive layer using a doctor blade to form a surface layer of about 2 μm.

The photosensitive material prepared in this way is used as a paper analyte (
Kawaguchi Electric, 5P-428) was charged to -6 kV, and the initial potential (Vo), dark charge retention rate (DRR), and half-decreased exposure (E'4) were measured, Vo = -580 V, D, respectively.
R,R,=87% and E+A56 (e r g/ci
〕Met.

Furthermore, in the same manner as in Example 1, a fully automatic plate making machine ELP4 was used.
When the plate was made using an ELP-T (ELP-T) at 0.04V, the density of the obtained offset printing master plate was 1.0 or more, and the image quality was clear.

Furthermore, after etching and printing with a printing machine, -
After printing 10,000 copies, the printed matter had no fog in the non-image area and the image was clear.

Example 3 37 g of n-butyl methacrylate, compound of the present invention (2
5) 60g, 2-hydroxyethyl methacrylate 3g
A mixed solution of 200 g of toluene was subjected to a polymerization reaction under the same conditions as in Example 2 to obtain a copolymer with a weight average molecular weight of 138,000.

A solution prepared by adding 0.15 g of toluene-2,4-diisocyanate to 20 g of a 5% by weight toluene solution of this copolymer was applied to the upper layer of the two-layer separation type photoreceptor prepared in Example 2 using a doctor blade. After drying at 110°C for 1 minute, heat treatment was further performed at 150"C for 30 minutes to obtain a thickness of approximately 1.8 μm.
A surface layer was formed. The electrostatic properties of the lithographic printing original plate prepared in this way were measured using paper analyte under the same conditions as in Example 2, and the results were as follows: Vo=-540VSDRR=
84%, E'A54. 5 (erg/c+1).

Next, the same operation as in Example 2 was carried out using a fully automatic plate making machine ELP-404V, and the density of the obtained offset printing master plate was 1.0 or more and the image quality was clear. Further, when etching was performed and printed on a printing press, the printed matter after printing 10,000 copies had no fog in the non-image area and the image was clear.

Example 4 40 g of butyl vinyl ether, 4-methylene-1,3-
A mixed solution of dioxolane Log and 100 g of ether was cooled to -78°C under a nitrogen stream, and BF,
- 5g of ether solution was added and reacted for 600 hours. Then add a methanol solution of ammonia to stop the polymerization.
The precipitated polymer was separated from the solvent by decantation, washed with n-hexane, and then dried under reduced pressure.

Subsequently, a 5% by weight toluene solution consisting of 8 layers of this copolymer and a [butyl methacrylate/acrylic acid (98/2) weight ratio] copolymer was applied to the upper layer of the photoreceptor prepared in Example 2 with a doctor. It was applied with a blade and dried at 110°C for 1 minute to form a surface layer of about 1°8 μm.

When the paper analyte electrostatic properties of the lithographic printing original plate prepared in this way were measured under the same conditions as in Example 2, Vo=-560V, D, RlR,=86%, E A
= 56 (er g /cJ).

Next, when the fully automatic plate making machine ELP-404V was operated in the same manner as in Example 1, the density of the obtained offset printing master plate was 1.0 or more and the image quality was clear. Furthermore, when etching was performed and printed on a printing press, the printed matter after printing 10,000 copies had no capri in the non-image area and the image was clear.

Examples 5 to 7 Lithographic printing original plates were prepared in the same manner as in Example 1, except that the following resins were used in place of the resins in the surface layer of Example 1. Next, the electrostatic properties were measured using a paper analyte in the same manner as in Example 2, and then the plate was operated using a fully automatic plate making machine ELP-404V. The results are shown in Table-2.

Similar results to Examples 1 and 2 were obtained.

(Effects of the Invention) From the above, the electrophotographic lithographic printing original plate having a hydrophilic layer containing the resin of the present invention in its surface layer has a coating that has both high hydrophilicity and water resistance after hydrophilic treatment. Moreover, since the adhesion to the substrate and toner image is also extremely good, the obtained lithographic printing original plate has excellent quality in terms of both scumming resistance and rigidity resistance.

Furthermore, the resin of the present invention is easy to manufacture.

Claims (1)

[Claims] providing at least one photoconductive layer on the conductive support;
Furthermore, in a lithographic printing original plate using an electrophotographic photoreceptor having a surface layer provided on the uppermost layer, at least two hydroxyl groups located sterically close to each other are treated with one protective group as a main component of the surface layer. What is claimed is: 1. An original plate for electrophotographic lithographic printing, characterized in that it contains at least one resin containing at least one functional group having at the same time protected form.