JP2002029168A - Lithographic printing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lithographic printing method, by which a stable and high quality printed matter can be easily obtained irrespective of the balance between an image part and a non-image part in lithographic printing, in which an emulsion ink is employed. SOLUTION: Printing is executed by applying an emulsion ink, which is obtained by emulsifying a mixture obtained by adding a hydrophilic component mainly made of water and/or polyhydric alcohol to an oil ink component, onto the original plate, which has non-image parts obtained by recording an image thereon and made of a thin film hydrophilic layer with a surface containing a metal oxide, of a lithographic printing plate. The preferable original plate of the lithographic printing plate is one having a support, on which the thin film hydrophilic layer having its surface containing the metal oxide is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing method using a heat-sensitive lithographic printing plate. More specifically, the present invention relates to a lithographic printing method capable of recording an image based on a digital signal and making a plate by a simple process. The present invention relates to a method of printing a lithographic printing plate which can form a plate printing plate, and can obtain a stable printed matter by using a lithographic printing plate in which a non-image portion is formed by a hydrophilic layer, without using fountain solution.

[0002]

2. Description of the Related Art In general, a lithographic printing plate comprises an oleophilic image area receiving ink during a printing process and a hydrophilic non-image area receiving fountain solution. Such lithographic printing is based on the property that water and oil-based ink repel each other, so that a lipophilic image area is an ink receiving area and a hydrophilic non-image area is a dampening water receiving area (an ink non-receiving area). ) Is a method of causing a difference in the adhesiveness of the ink on the plate surface, depositing the ink only on the image portion, and then transferring the ink to a printing medium such as paper to print. PS plates in which a lipophilic photosensitive resin layer is provided on a hydrophilic support are widely used. As a plate making method, usually, a lithographic printing plate precursor is exposed through an original such as a lith film using a photolithography technique, and then a photosensitive layer is left in an image area, and a non-image area is developed with a developer. To dissolve and remove the surface of the aluminum substrate, and form a dampening water layer on the exposed surface of the hydrophilic aluminum substrate to prevent the adhesion of ink. In this method, it was necessary to supply water called a fountain solution or a liquid containing water as a main component from the printing press to the plate surface.
It is difficult to balance the supply of water and ink, and it is necessary to constantly control the amount of dampening water during printing.To control the appropriate amount of dampening water, skills and experience are required. Not only that, a large amount of dampening solution waste liquid was generated, and the amount of waste paper at the start of printing was also large.

On the other hand, as a simple lithographic printing method using no dampening solution, Japanese Patent Publication No. 54-26923, Japanese Patent Publication No. 57-3060, Japanese Patent Publication No. 56-12862, and Japanese Patent Publication No. 56-23150 No., JP-B-56-3
No. 0856, JP-B-60-60051, JP-B-61-54220, JP-B-61-54222, JP-B-61-54223, and JP-B-61-6.
No. 16, JP-B-63-23544, JP-B-2
JP-A-25498, JP-B-3-56622, JP-B-4-28098, JP-B5-1934, JP-A-2-63050, JP-A-2-6305
No. 1 is proposed. These use a lithographic printing plate that has a silicone rubber layer as the ink repellent layer in the non-image area, so printing can be performed without ink adhering to the non-image area, even if fountain solution is not supplied during printing. It has the feature that it is.

[0004] Japanese Patent Publication No. 49-26844, Japanese Patent Publication No. 49-27124, and Japanese Patent Publication No. 49-27125.
JP, JP-A-53-36307, JP-A-53-36307
No. 36308, JP-B-61-52867, JP-A-58-2114844, JP-A-53-278
03, JP-A-53-29807, JP-A-5-29807
JP-A-4-146110, JP-A-57-212274, JP-A-58-37069, JP-A-54-1
No. 06305 discloses lithographic printing using emulsion ink. These emulsion inks are emulsions of water-containing inks, and since water and ink are separated on the plate surface, water can be supplied from the ink side. It is a feature. However, when the emulsion ink is applied to a conventional lithographic printing plate having a hydrophilic aluminum substrate surface as a non-image portion, there has been a problem that water is lost due to excess water or ground stain is apt to occur due to insufficient water. . This is because, while the quantitative balance of the ink and water supplied from the emulsion ink is constant, the ratio of the non-image part to which water is supplied and the image part to which ink is supplied varies greatly depending on the printed matter. This is considered to be due to the fact that the width of the balance between the ink and water on the plate surface is small.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems when an emulsion ink is applied to lithographic printing. That is, an object of the present invention is to provide a lithographic printing method capable of easily obtaining a stable and high-quality printed matter in lithographic printing to which an emulsion ink is applied, regardless of the balance between the image area and the non-image area. It is in. A further object of the present invention is to provide a novel method of using a hydrophilic layer which can be suitably used for supplying water from an emulsion ink, instead of using a hydrophilic surface of an aluminum substrate as a non-image portion. .

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the use of a lithographic printing plate provided with a thin film hydrophilic layer having a surface containing a metal oxide in a non-image portion allows the use of the lithographic printing plate. The inventors have found that the problem can be solved, and completed the present invention. That is, the lithographic printing method of the present invention performs image recording on a lithographic printing plate precursor to form a non-image portion region composed of a thin film hydrophilic layer having a surface containing a metal oxide,
The printing is characterized by adding a hydrophilic component containing water and / or a polyhydric alcohol as a main component to the oil-based ink component and emulsifying the emulsion-based ink to print. The lithographic printing plate precursor applied to the printing method of the present invention is a lithographic printing plate precursor comprising a support having an oil-based ink-receiving layer formed on its surface, or a metal oxide on a support having an oil-based ink-receiving surface. Is preferably provided with a thin-film hydrophilic layer having a surface containing

Although the reason why the thin film hydrophilic layer having a surface containing a metal oxide works effectively in printing using the emulsion ink of the present invention is not necessarily clear, an aluminum substrate which has been hydrophilized by a conventional surface treatment is not always clear. Compared to the surface, the thin film hydrophilic layer having the surface containing the metal oxide is superior in hydrophilicity to the conventional hydrophilic surface in which the hydrophilicity is improved by physical roughening. However, since there are few fine irregularities, the smoothness is high, and the surface area is small, the surface of the non-image area can be sufficiently covered even when the hydrophilic component existing on the plate surface is small, and the uniform hydrophilic component Since it is possible to form a liquid film, it is considered that the allowable range of the ratio of the amount of the oil-based ink component and the amount of the hydrophilic component on the plate surface becomes wider.

[0008]

Embodiments of the present invention will be described below in detail. The lithographic printing plate precursor applied to the printing method of the present invention is such that a specific hydrophilic layer exposed on the surface of the plate by image formation forms a non-image portion, and similarly, an oil-based ink-receiving layer exposed on the surface of the plate forms an image. Each part is formed, and the emulsion ink used at the time of printing is separated, whereby the oily ink component is deposited on the image part (oily ink receiving layer),
By supplying the hydrophilic component to the non-image area to form an ink-repellent area, high-quality printed matter can be stably obtained without supplying dampening water.

[Emulsion ink] The emulsion ink used in the present invention is an emulsion ink obtained by adding a hydrophilic component to an oil-based ink component and emulsifying it.
ter in oil) type or O / W (oil in water) type. Further, the emulsion ink used in the present invention, in the ink fountain of the printing machine when applied to printing and printing in an ink can, maintain a stable emulsified state,
At the time of printing, the inking system (ink supply system) is transferred while receiving the share, and when the ink reaches the inking roller, the emulsification is destroyed and the hydrophilic component is separated and supplied onto the plate surface. On the plate surface, the hydrophilic component adheres to the non-image area to form a liquid film, and the oil-based ink component is prevented from adhering, while the oil-based ink component adheres to the image area. Any emulsion ink having such a function can be used in the present invention without any particular limitation. Further, in order for the emulsion ink of the present invention to exhibit the above function, it is more preferable to use a printing machine equipped with a cooling mechanism in the inking system.

The proportion of the oily ink component and the hydrophilic component in the emulsion ink of the present invention is 5 to 150 parts by weight, preferably 10 to 120 parts by weight, more preferably 100 parts by weight of the oily ink component. Preferably, 20 to
100 parts by weight. As the oil-based ink component of the emulsion ink of the present invention, vegetable oil, synthetic resin varnish or natural resin varnish, or a synthetic varnish thereof,
An ordinary oil-based ink comprising a high-boiling petroleum solvent, a pigment, and other additives (such as a friction resistance improver, an ink dryer, and a drying inhibitor) can be used. As the hydrophilic component of the emulsion ink of the present invention, water and / or polyhydric alcohols can be used. Examples of polyhydric alcohols include glycerin, diglycerin, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, sorbitol, butanediol, pentanediol, and the like. Among them, glycerin, ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol can be preferably used. The polyhydric alcohol may be used alone, or two or more kinds may be used as a mixture, and may be used as a mixture with water. The preferred content of the polyhydric alcohol in the hydrophilic component of the present invention is 30 to 100% by weight, more preferably 50 to 100% by weight.

The hydrophilic component of the emulsion ink according to the present invention may further comprise, in addition to the above, an additive for the purpose of improving emulsion stability, improving flow characteristics, improving hydrophilicity, suppressing evaporation of the hydrophilic component, and the like. Can be used. For example,
Monohydric alcohols such as methanol and ethanol; amino alcohols such as monoethanolamine and diethanolamine; known nonionic, anionic, cationic and betaine surfactants; and oxyacids such as glycolic acid, lactic acid and citric acid Carboxylic acids, polyvinylpyrrolidone,
Examples include hydrophilic polymers such as polyacrylic acid, gum arabic, and carboxymethyl cellulose, and inorganic acids and salts such as phosphoric acid, silicic acid, nitric acid, and salts thereof.

[Image forming method] In the printing method of the present invention, the non-image area of a lithographic printing plate provided with a thin hydrophilic layer having a surface containing a metal oxide contains at least a metal oxide on a substrate. It is formed by forming an image on a lithographic printing plate precursor provided with a thin film hydrophilic layer having a surface to be formed. Examples of the image forming method include (a) a method of forming a lipophilic image area on a lithographic printing plate precursor provided with the hydrophilic layer on a substrate by a known method such as an ink jet method; ) A lithographic printing plate precursor having a hydrophilic layer and a heat-sensitive or photosensitive lipophilic layer sequentially provided on a substrate, and a lipophilic layer serving as a non-image portion formed by a known heat-sensitive or photosensitive image recording method. A method of forming an image portion by removing, and (c) a method of recording a known heat-sensitive or photosensitive image on a lithographic printing plate precursor having a heat-sensitive or photosensitive lipophilic layer and a hydrophilic layer sequentially provided on a substrate Thus, a method of removing the hydrophilic layer in a portion to be an image portion to form an image portion can be applied. Among them, lithographic printing plate precursors, which form images by a thermal image recording method, are insensitive to light of a normal illuminance level such as indoor lighting, and have the advantage that thermal-recorded images do not require fixing. And preferably used in the present invention. In the present invention, the non-image area of the lithographic printing plate on which an image is formed is characterized in that it is formed of a thin film hydrophilic layer having a surface containing a metal oxide.
The configuration of the lithographic printing plate precursor and the means used for image formation are not particularly limited. Here, for the sake of convenience, an example of a lithographic printing plate precursor that is provided with a heat-sensitive lipophilic layer and a hydrophilic layer in order on a substrate and capable of recording a heat-sensitive image with a laser beam will be described in detail below.

[Structure of Lithographic Printing Plate Precursor] A substrate on which a thermosensitive image can be recorded by a laser beam used in the present invention is provided.
As an embodiment of a lithographic printing plate precursor sequentially provided with a heat-sensitive lipophilic layer and a specific hydrophilic layer shown below, for example, an oil-based ink-receiving layer and a hydrophilic layer having a light-to-heat conversion function are sequentially provided on a substrate. A hydrophilic overcoat that has a hydrophilic layer and a light-to-heat conversion function and is removable on a substrate having an oil-based ink-receiving surface or an oil-based ink-receiving layer formed on the surface. Embodiments in which layers are sequentially provided are exemplified.

(Hydrophilic Layer Having Surface Containing Metal Oxide) The hydrophilic layer used in the present invention is a thin film having a hydrophilic metal oxide on its surface. This is a layer that receives and retains a sexual component and functions as a non-image portion. The thin film used for the hydrophilic layer of the present invention is not particularly limited as long as the surface of the thin film is made of a hydrophilic metal oxide, and includes a thin film of a metal or a metal compound having a hydrophilic metal oxide on the surface. .
Examples of the metal or metal compound that can be used for forming the thin film hydrophilic layer having a surface containing the metal oxide of the present invention include d-block (transition) metal, f-block (lanthanoid) metal, aluminum, and indium. , Lead, tin, or metal oxides corresponding to silicon and alloys and their respective metals, metal carbides, metal nitrides, metal borides,
Metal sulfides, metal halides, which are
It can be used in the form of a mixture (including a uniform mixed film, a non-uniform mixed film, and a laminated film). Above all, an embodiment in which the thin film hydrophilic layer is constituted by the metal oxide thin film itself is particularly preferable. Examples of the metal oxide thin film include indium oxide, tin oxide, tungsten oxide, manganese oxide, silicon oxide, titanium oxide, aluminum oxide, and aluminum oxide. A thin film of zirconium oxide or the like and a mixed thin film thereof can be suitably used as the hydrophilic layer of the present invention. In forming the thin film hydrophilic layer of the present invention, metals and metal compounds other than metal oxides can be used as a material,
These thin film surfaces are substantially highly oxidized in the atmosphere, and the action of this oxidation results in the presence of metal oxides on the surface, and therefore can be used in the present invention. However, in order to further ensure the content of the metal oxide on the surface, after forming a thin film of the metal and the metal compound, in order to promote oxidation of the surface, heat treatment or humidification treatment Alternatively, a process such as a glow discharge process may be performed. Further, the thin-film hydrophilic layer according to the present invention is not limited to a single-layer structure, but is formed by forming a thin film of these metals and metal compounds, and further laminating a metal oxide thin film on the surface of the thin film. It may have a layered structure. In the case of the multilayer structure, it is needless to say that the metal oxide must be contained in the uppermost layer exposed on the surface.

For forming a thin film of a metal or a metal compound used for the thin film hydrophilic layer according to the present invention, a PVD method (physical vapor deposition method) such as a vacuum vapor deposition method, a sputtering method, an ion plating method, or a CVD method (chemical vapor deposition method). ) And the like are appropriately used. For example, in a vacuum evaporation method, resistance heating, high-period induction heating, electron beam heating, or the like can be used as a heating method. In addition, oxygen, nitrogen, or the like may be introduced as a reactive gas, or reactive vapor deposition using means such as ozone addition or ion assist may be used.

When a sputtering method is used, a pure metal or a target metal compound can be used as a target material. When a pure metal is used, oxygen, nitrogen, or the like is introduced as a reactive gas. DC power supply,
A pulse DC power supply or a high-frequency power supply can be used.

Prior to the formation of a thin film by the above method, the substrate may be degassed by heating the substrate, or may be subjected to vacuum glow treatment on the surface of the lower layer in order to improve the adhesion to the lower layer.
For example, in vacuum glow processing, 1 to 10 mtorr
A high frequency is applied to the substrate under a pressure of about r to form a glow discharge, and the substrate can be processed by the generated plasma. Further, the effect can be improved by increasing the applied voltage or introducing a reactive gas such as oxygen or nitrogen.

The thickness of the thin film hydrophilic layer according to the present invention is preferably from 10 nm to 3000 nm. More preferably, it is 20 to 1500 nm. If the thickness is too small, undesired results such as a decrease in retention of the hydrophilic component of the emulsion ink and the film strength are reduced. If the thickness is too large, undesired results such as a decrease in image recording sensitivity are provided.

(Oil-Based Ink-Receiving Layer) The oil-based ink-receiving layer of the lithographic printing plate precursor used in the present invention is a layer that receives the oil-based ink component of the emulsion ink in printing and functions as an image area. This is a layer containing an organic polymer having an ink receptive surface. Further, the oil-based ink-receiving layer used in the present invention is applied on a substrate, or when the substrate itself has an oil-based ink component-receiving surface (for example, a plastic film or a substrate on which a plastic film is laminated). And the like, the substrate may also function as the oil-based ink-receiving layer. (Detailed description of the substrate will be described later.)

As the organic polymer used for the material of the oil-based ink receiving layer according to the present invention, those having a lipophilic film-forming ability are selected. Furthermore, in order to improve the printing durability and solvent resistance of the ink receiving layer, it is preferable to improve the film strength by previously hardening the coating film by adding a crosslinking agent or the like.

Useful organic polymers that can be used include polyesters, polyurethanes, polyureas, polyimides,
Posisiloxane, polycarbonate, phenoxy resin,
Epoxy resin, phenol / formaldehyde resin, alkylphenol / formaldehyde resin, polyvinyl acetate, acrylic resin and its copolymer, polyvinylphenol, polyvinylhalogenated phenol, methacrylic resin and its copolymer, acrylamide copolymer, methacrylamide copolymer , Polyvinyl formal, polyamide, polyvinyl butyral, polystyrene, cellulose ester resin, polyvinyl chloride, polyvinylidene chloride, and the like. Among these,
As a more preferable compound, a resin having a hydroxyl group, a carboxy group, a sulfonamide group or a trialkoxysilyl group in a side chain is excellent in adhesion to a substrate or an upper hydrophilic layer, and is easily cured when a crosslinking agent is used as desired. It is desirable. In addition, an acrylonitrile copolymer, a polyurethane, a copolymer having a sulfonamide group in a side chain or a copolymer having a hydroxyl group in a side chain which is photocured with a diazo resin are preferably used.

Other phenol, cresol (m-cresol, p-cresol, m / p mixed cresol), phenol / cresol (m-cresol, p-cresol, m / p mixed cresol), phenol-modified xylene, tert-butylphenol, A novolak resin and a resole resin of condensation with formaldehyde such as octylphenol, resorcinol, pyrogallol, catechol, chlorophenol (m-Cl, p-Cl), bromophenol (m-Br, p-Br), salicylic acid, and phloroglucinol; Further, a condensation resin of the above phenol compound and acetone is useful.

As other suitable high molecular compounds, there can be mentioned copolymers having a molecular weight of usually 10,000 to 200,000, which contains the following monomers (1) to (12) as constituent units. (1) Acrylamides, methacrylamides, acrylates, methacrylates and hydroxystyrenes having an aromatic hydroxyl group, for example, N- (4
-Hydroxyphenyl) acrylamide or N- (4
-Hydroxyphenyl) methacrylamide, o-, m-
And p-hydroxystyrene, o-, m- and p-
Hydroxyphenyl acrylate or methacrylate, (2) acrylates and methacrylates having an aliphatic hydroxyl group, for example, 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, (3) methyl acrylate, ethyl acrylate, acryl Propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, cyclohexyl acrylate, octyl acrylate, phenyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, 4-hydroxybutyl acrylate, glycidyl acrylate, N- (Substituted) acrylates such as dimethylaminoethyl acrylate,

(4) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate,
Amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, octyl methacrylate, phenyl methacrylate, benzyl methacrylate, methacrylic acid
(Substituted) methacrylates such as 2-chloroethyl, 4-hydroxybutyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl methacrylate, (5) acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N- Ethyl acrylamide, N-ethyl methacrylamide, N-hexyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-cyclohexyl methacrylamide, N-hydroxyethyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N- Phenyl methacrylamide, N-benzylacrylamide, N
-Benzyl methacrylamide, N-nitrophenyl acrylamide, N-nitrophenyl methacrylamide, N
Acrylamide or methacrylamide such as -ethyl-N-phenylacrylamide and N-ethyl-N-phenylmethacrylamide,

(6) Ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether,
Vinyl ethers such as octyl vinyl ether and phenyl vinyl ether; (7) vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate; (8) styrenes such as styrene, methyl styrene and chloromethyl styrene; 9)
Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone; (10) olefins such as ethylene, propylene, isobutylene, butadiene, and isoprene; (11) N
-Vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile and the like,

(12) N- (o-aminosulfonylphenyl) acrylamide, N- (m-aminosulfonylphenyl) acrylamide, N- (p-aminosulfonylphenyl) acrylamide, N- [1- (3-aminosulfonyl) Naphthyl] acrylamide, acrylamides such as N- (2-aminosulfonylethyl) acrylamide, N- (o-aminosulfonylphenyl) methacrylamide, N- (m-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonyl) Methacrylamides such as phenyl) methacrylamide, N- [1- (3-aminosulfonyl) naphthyl] methacrylamide, N- (2-aminosulfonylethyl) methacrylamide, and o-aminosulfonylphenyl acrylate, m-amino Sulfo sulfonyl phenyl acrylate,
p-aminosulfonylphenyl acrylate, 1- (3
-Aminosulfonylphenylnaphthyl) unsaturated sulfonamides such as acrylates such as acrylate, o-aminosulfonylphenylmethacrylate, m
Unsaturated sulfonamides such as methacrylic esters such as -aminosulfonylphenyl methacrylate, p-aminosulfonylphenyl methacrylate and 1- (3-aminosulfonylphenylnaphthyl) methacrylate;

The organic polymer used in the present invention is, for example, nitrocellulose or a resin containing a t-butoxycarbonyl group or an acetal group as described in "J.
Imaging Sci., P59-64, 30 (2), (1986) (Frechet et al.) "
And "Polymers in Electronics (Symposium Series, P1
1, 242, T. Davidson, Ed., ACS Washington, DC (1984) (I
to, Willson) "," Microelectronic Engineering, P3-1
0,13 (1991) (E. Reichmanis, LFThompson), but not limited thereto. These polymers may be used alone or as a mixture of two or more.

In this embodiment, a lithographic printing plate precursor having a heat-sensitive oil-based ink-receiving layer is described.
In such an embodiment, it is preferable that the oil-based ink receiving layer has a light-to-heat conversion function from the viewpoint of sensitivity. When the oil-based ink-receiving layer has a light-to-heat conversion capability, the oil-based ink-receiving layer may contain a light-to-heat conversion material capable of absorbing laser light used for image recording and converting the light into heat. it can. Examples of the photothermal conversion material used in the oil-based ink receiving layer include those that absorb light having a wavelength used for image recording and convert it into heat.For example, when a laser light source is an infrared laser, an infrared absorbing dye, Various organic and inorganic materials that absorb the laser wavelength used for image recording, such as infrared absorbing pigments, infrared absorbing metals, and infrared absorbing metal oxides, can be used. Tall ones are preferred.

Examples of pigments include various carbon blacks such as acidic carbon black, basic carbon black and neutral carbon black, various carbon blacks whose surface is modified or coated to improve dispersibility, etc.
Nigrosines and dyes include "infrared sensitizing dyes" (Matsuoka, Plenum Press, New York, NY (1990)), US4833.
124, EP-321923, U.S. Pat.
US-4942141, US-4948776, US-
4948777, US-4948778, US-495
0639, US-4912083, US-495255
2, various compounds described in the specification such as US Pat. No. 5,023,229, and metals or metal oxides include aluminum,
Indium tin oxide, tungsten oxide, manganese oxide, titanium oxide and the like, as well as conductive polymers such as polypyrrole and polyaniline can be used. The amount used is 2% based on the total solid weight of the oil-based ink receiving layer.
% By weight, preferably 5% by weight to 45% by weight, more preferably 10% by weight to 40% by weight.

The oil-based ink-receiving layer can be provided by dissolving the above composition in an appropriate solvent, applying the composition on a substrate, and drying. The organic polymer alone can be used by dissolving it in a solvent, but usually a crosslinking agent, an adhesion aid,
Used together with a coloring agent, inorganic or organic fine particles, a coating surface condition improving agent or a plasticizer. Further, a heat-decomposable compound for enhancing the laser recording sensitivity or a heating color-developing system or a decoloring system for forming a printout image after exposure may be added. Hereinafter, typical additives will be described.

As a known crosslinking agent for crosslinking an organic polymer used for improving the film properties, specifically, for example,
Diazo resin, aromatic azide compound, polyfunctional isocyanate compound, polyfunctional epoxy compound, polyfunctional amine compound, polyol compound, polyfunctional carboxyl compound, aldehyde compound, polyfunctional (meth) acrylic compound, polyfunctional vinyl compound, polyfunctional mercapto Compounds, polyvalent metal salt compounds, polyalkoxysilane compounds, polyalkoxytitanium compounds, polyalkoxyaluminum compounds, polymethylol compounds, polyalkoxymethyl compounds, and the like.A known reaction catalyst may be added to promote the reaction. It is possible. The amount used is from 0% by weight to 50% by weight, preferably from 3% by weight to 40% by weight, more preferably from 5% by weight to 35% by weight, based on the total solid weight in the coating liquid of the oil-based ink-receiving layer. It is.

As the adhesion aid, the above-mentioned diazo resin is excellent in adhesion to the substrate and the hydrophilic layer. In addition, silane coupling agents, isocyanate compounds, and titanium-based coupling agents are also useful.

As the coloring agent, ordinary dyes and pigments are used. In particular, rhodamine 6G chloride, rhodamine B chloride, crystal violet, malachite green oxalate, oxazine 4 perchlorate, quinizarin,
2- (α-naphthyl) -5-phenyloxazole and coumarin-4. Specifically, as other dyes,
Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black B
Y, oil black BS, oil black T-505
(The above are manufactured by Orient Chemical Industry Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI4255)
5), methyl violet (CI42535), ethyl violet, methylene blue (CI52015), patent pure blue (manufactured by Sumitomo Sangoku Chemical Co., Ltd.), brilliant blue, methyl green, erythricin B, basic fuchsin, m-cresol purple, auramine, 4
Triphenylmethane-based, diphenylmethane-based, oxazine-based, xanthene-based, iminonaphthoquinone-based, azomethine-based or anthraquinone-based dyes such as -p-diethylaminophenyliminaphthoquinone and cyano-p-diethylaminophenylacetanilide; -293247, Japanese Patent Application No. 7-335.
And dyes described in JP-A-145-145 or the gazette. When the above dye is added to the oil-based ink receiving layer, it is usually about 0.02 to 10% by weight, more preferably about 0.2% by weight, based on the total solid content of the oil-based ink receiving layer.
It is a ratio of 1 to 5% by weight.

Further, fluorine-based surfactants and silicon-based surfactants, which are well-known compounds as coating surface condition improvers, can also be used. Specifically, a surfactant having a perfluoroalkyl group or a dimethylsiloxane group is useful for preparing the coated surface.

Examples of the inorganic or organic fine powder usable in the present invention include colloidal silica and colloidal aluminum having an average particle size of 10 nm to 100 nm, and inert particles having a particle size larger than these colloids, for example, silica particles. , Surface-hydrophobized silica particles, alumina particles,
Examples include titanium dioxide particles, other heavy metal particles, clay and talc. The addition of these inorganic or organic fine powders to the oil-based ink-receiving layer has the effect of improving the adhesion to the upper hydrophilic layer and increasing the printing durability in printing. The addition ratio of these fine powders in the oil-based ink-receiving layer is preferably 80% by weight or less, more preferably 40% by weight or less of the total amount.

In the present invention, as the thermally decomposable compound for improving the recording sensitivity of a laser which can be used for image recording, a known compound which decomposes upon heating to generate a gas can be used. In this case, laser recording sensitivity can be improved due to rapid volume expansion in the exposed portion of the surface of the oil-based ink receiving layer. Examples of these additives include dinitiro pentamethylenetetramine, N, N'-dimethyl-N, N'-dinitrosoterephthalamide, p-toluenesulfonylhydrazide, 4,4-oxybis (benzenesulfonylhydrazide), diamide Benzene and the like can be mentioned. Further, as the thermally decomposable compound for improving laser recording sensitivity, various iodonium salts, sulfonium salts, phosphonium tosylate, oxime sulfonate, dicarbodiimide sulfonate, triazine, etc. Known compounds of the resulting thermal acid generator can be used as additives.
By using these together with a chemical amplification system binder,
It is possible to greatly lower the decomposition temperature of the chemically amplified binder as a constituent material of the heat-sensitive layer, and as a result, to improve the laser recording sensitivity. The addition ratio is preferably from 1% by weight to 20% by weight, more preferably from 5% by weight to 10% by weight, based on the total amount of the oil-based ink-receiving layer.

If necessary, a plasticizer is added to the oil-based ink-receiving layer of the present invention in order to impart flexibility to the coating film. For example, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, oligomers of acrylic acid or methacrylic acid And polymers.

Further, it is preferable to add a color-forming or decoloring compound to the oil-based ink-receiving layer of the present invention in order to clearly distinguish an image area from a non-image area when exposed. For example, together with a thermal acid generator such as a diazo compound or a diphenyliodonium salt, a leuco dye (leucomalachite green, leuco crystal violet, a lactone of crystal violet, etc.) or a PH discoloration dye (eg, ethyl violet, Victoria Poor Blue BO)
H and the like). In addition, EP 897134
A combination of an acid-coloring dye and an acidic binder as described in the specification is also effective. In this case, the bond in the associated state forming the dye is broken by heating, and a lactone is formed to change from colored to colorless. The addition ratio of these coloring systems is preferably 10% by weight or less, more preferably 5% by weight or less, based on the total amount in the heat-sensitive layer.

As the solvent for forming the oil-based ink receiving layer by coating, alcohols (methanol, ethanol, propyl alcohol, ethylene glycol,
Diethylene glycol, propylene glycol, dipropylene glycol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, etc.), ethers (tetrahydrofuran, ethylene glycol dimethyl ether, propylene glycol dimethyl ether, tetrahydropyran, etc.), ketones (acetone, Use methyl ethyl ketone, acetylacetone, etc., esters (methyl acetate, ethylene glycol monomethyl monoacetate, etc.), amides (formamide, N-methylformamide, pyrrolidone, N-methylpyrrolidone, etc.), gamma-butyrolactone, methyl lactate, ethyl lactate, etc. be able to. These solvents are used alone or in a mixed state. When preparing a coating solution, the concentration of the components of the oil-based ink-receiving layer (total solids including additives) in the solvent is preferably 1 to 50% by weight. In addition, a film can be formed not only from the above-mentioned application from an organic solvent but also from an aqueous emulsion. In this case, the concentration is preferably 5% by weight to 50% by weight.

The thickness of the oil-based ink receiving layer of the present invention after coating and drying is not particularly limited, but may be 1.0 g / m ² or more. When it is provided on a metal plate, it also has a role as a heat insulating layer, so that it is preferably 0.5 g / m ² or more. If the oil-based ink receptive layer is too thin, the heat generated will dissipate toward the metal plate, lowering the sensitivity. In addition, in the case of a hydrophilic metal plate, abrasion resistance is required, so that the printing durability cannot be ensured. When a lipophilic plastic film is used as the substrate, the coating amount of the oil-based ink-receiving layer may be smaller than that of the metal plate, and the thickness of the dried film is preferably 0.05 μm or more.

(Overcoat Layer) In the lithographic printing plate precursor applied to the method of the present invention, an overcoat layer can be formed, if necessary, in addition to the hydrophilic layer and the oil-based ink-receiving layer. The overcoat layer used in the present invention is a layer that is easily removed before or during printing, has a function of protecting a hydrophilic surface, and contains a polymer compound capable of forming a film. Further, the overcoat layer of the present invention may have a light-to-heat conversion function. In this case, a light-to-heat conversion substance can be contained in the overcoat layer.

As a method of providing an overcoat layer,
The coating solution containing the overcoat layer composition may be directly applied and dried on the hydrophilic layer, or the coating solution may be applied on another support and dried, and then applied on the hydrophilic layer. May be provided by pressure bonding (lamination), and the support may be peeled off and provided. The polymer used for the overcoat layer is
It is a known organic or inorganic resin, and a film formed by coating and drying has a film-forming ability. Further, at the time of printing, when it is removed with an emulsion ink, the hydrophilic component of the emulsion ink, particularly water as well as/
Alternatively, it is preferable that the compound be easily dissolved or dispersed in polyhydric alcohols. As such a polymer, it is preferable to use a hydrophilic polymer. Specific examples of such a hydrophilic polymer include polyvinyl acetic acid (having a hydrolysis rate of 65% or more) and polyacryl. Acid and its alkali metal salt or amine salt, polyacrylic acid copolymer and its alkali metal salt or amine salt, polymethacrylic acid and its alkali metal salt or amine salt, polymethacrylic acid copolymer and its alkali metal salt or amine salt,
Polyacrylamide and its copolymer, polyhydroxyethyl acrylate, polyvinylpyrrolidone and its copolymer, polyvinyl methyl ether, polyvinyl methyl ether / maleic anhydride copolymer, poly-2-acrylamide-2-methyl-1-propanesulfone Acid and its alkali metal salt or amine salt, poly-2-acrylamido-2-methyl-1-propanesulfonic acid copolymer and its alkali metal salt or amine salt, gum arabic,
Cellulose derivatives (eg, carboxymethyl cellulose,
(Carboxyethyl cellulose, methyl cellulose, etc.) and modified products thereof, white dextrin, pullulan, enzymatically decomposed etherified dextrin, and the like.
Further, according to the purpose, two or more of these resins can be used in combination.

By adding a light-to-heat conversion material to the overcoat layer, the sensitivity in heat-sensitive recording can be improved. The photothermal conversion material that can be used here is a photothermal conversion material that can absorb laser light used for image recording and convert it into heat, and various pigments and dyes can be used. When removing with an emulsion ink, it is preferred that it be easily dissolved or dispersed in a hydrophilic component of the emulsion ink, particularly, water and / or a polyhydric alcohol. When an infrared laser is used as the laser light source that is a recording light source, various organic and inorganic materials that absorb light having a laser wavelength used for image recording, such as an infrared absorbing dye, an infrared absorbing pigment, an infrared absorbing metal, and an infrared absorbing metal oxide. Material is available.

As the pigment having the property of easily dissolving or dispersing in a hydrophilic component, for example, as a pigment, a method of surface-coating a hydrophilic resin, a method of attaching a surfactant, a reactive substance (eg, silica sol) , Alumina sol,
A method of bonding a silane coupling agent, an epoxy compound, an isocyanate compound, etc.) to the pigment surface (the above surface treatment method is described in "Properties and Applications of Metallic Soap" (Koshobo),
"Printing ink technology" (CMC Publishing, 1984) and "Latest Pigment Application Technology" (CMC Publishing, 1986)
It is described in. Pigments that have been surface-treated according to ()) are suitable. Among them, carbon black coated with a hydrophilic resin and carbon black modified with silica sol are preferably used as those which are easily dispersed in a water-soluble resin and do not impair hydrophilicity.

Examples of the fine particles of metal or metal oxide include, for example, a surface treatment with a surfactant, a surface treatment with a substance having a hydrophilic group that reacts with the constituent material of the particles, and a protective colloid having a hydrophilic property. Fine particles of metal or metal oxide that have been subjected to a surface hydrophilic treatment by a method such as providing a polymer film are suitable. Particularly preferable is a surface silicate treatment. For example, in the case of iron fine particles or iron tetroxide fine particles, sodium silicate (3%) at 70 ° C.
The surface can be made sufficiently hydrophilic by immersing it in an aqueous solution for 30 seconds. Other metal fine particles and metal oxide fine particles can be subjected to surface silicate treatment in the same manner. Hydrophilization of the surface, such as by aluminate treatment or titanate treatment, can be performed in the same manner, or by using a surface etching aid such as sodium pyrophosphate, sodium carbonate, sodium hydroxide, or the like. I can do it. Among them, metal oxide fine particles with a hydrophilic surface,
In particular, fine particles of metal oxide whose surface is silicate-treated, particularly fine particles of iron oxide or iron whose surface is silicate-treated are preferably used.

As the dye, US Pat. No. 5,15
The near-infrared absorption sensitizers described in US Pat. No. 6,938,938 are also preferably used, and substituted arylbenzo (thio) pyrylium salts described in US Pat. No. 3,881,924;
No. 7-142645 (U.S. Pat. No. 4,327,169)
No. 3) described in JP-A-58-1983.
No. 181051, No. 58-220143, No. 59-4
Nos. 1363, 59-84248, 59-8424
No. 9, No. 59-146063, No. 59-146061
Pyrylium compounds described in JP-A-59-
No. 216146, US Pat.
No. 83,475, such as pentamethine thiopyrylium salt and the like, and pyrylium compounds disclosed in Japanese Patent Publication Nos. 5-135514 and 5-19702, are commercially available as Epollight III-178 manufactured by Eporin. , Ep
light III-130, Epollight III-1
25 and the like are particularly preferably used. In these dyes,
A water-soluble cyanine dye represented by the following formula (I) is particularly preferably used.

[0047]

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Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶
Represents a substituted or unsubstituted alkyl group, and Z ¹ and Z ² represent a substituted or unsubstituted phenyl group or a naphthalene group. L is a substituted or unsubstituted methine group, and when it has a substituent, the substituent is an alkyl group having 8 or less carbon atoms, a halogen atom or an amino group, or
The substituents on the two methine carbons may include a cyclohexene ring or a cyclopentene ring which may have a substituent formed by bonding to each other, and the substituent may be an alkyl group having 6 or less carbon atoms. Or a halogen atom. X
^- represents an anionic group. n is 1 or 2; and R ¹ ,
At least one of R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , Z ¹ and Z ² represents an acidic group or a substituent having an alkali metal base or an amine base of an acidic group.

Specific compounds of the water-soluble cyanine dye represented by the following formula (I) [exemplified compounds (I-1) to (I)
−32)], but the present invention is not limited to these.

[0050]

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[0051]

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[0052]

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[0053]

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[0054]

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[0055]

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[0056]

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[0057]

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The amount of the light-to-heat converting substance used is 1 to 70% by weight, preferably 2 to 50% by weight based on the total solid content of the overcoat layer.
% By weight, in the case of a dye, particularly preferably 2 to 30% by weight,
In the case of pigments, the proportion is particularly preferably 20 to 50% by weight. If the amount of the pigment or dye is too small, the sensitivity improving effect will be insufficient. If the amount is too large, the uniformity of the layer will be lost and the durability of the layer will be poor.

In addition, in the overcoat layer, the physical strength of the film is improved, the dispersibility of the components constituting the film is improved, the applicability is improved, the removability of the film is improved, and an adjacent layer, for example, For the purpose of improving adhesion to the surface of the thin film hydrophilic layer, for example, plasticizers, pigments, dyes, surfactants, particles,
It is possible to add an adhesion improver and the like. For example, when the overcoat layer is provided by application of an aqueous solution, a nonionic surfactant is mainly added for the purpose of improving the uniformity of application. Specific examples of such a nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan triolate, stearic acid monoglyceride, and polyoxyethylene nonyl phenyl ether. The proportion of the nonionic surfactant in the total solid matter of the overcoat layer is preferably 0.05 to 5% by weight, more preferably 1 to 3% by weight.

[0060] The coating amount of the overcoat layer used in the present invention is preferably 0.05~4.0g / m ^2, more preferred range is 0.1 to 1.0 g / m ^2. If the overcoat layer is too thick, it takes time to remove it before or during printing, and if it is too thin, the film properties may be impaired. The properties of the overcoat layer, particularly the influence on the sensitivity, also depend on the content of the light-to-heat conversion substance in the layer, but if the thickness is too thick or too thin, the sensitivity tends to decrease.

(Substrate) As the substrate of the lithographic printing plate precursor applicable to the method of the present invention, a dimensionally stable plate is used. Paper, lipophilic plastic (eg, polyethylene, polypropylene, polystyrene, etc.) laminated paper, metal plate (eg, aluminum, zinc, copper,
Nickel, stainless steel plate, etc.), the above metal plate coated with an organic polymer resin, plastic film (for example, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate,
Cellulose nitrate, polyethylene terephthalate, polyethylene naphthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), the above-mentioned plastic film on which an organic polymer resin is applied, the above-mentioned plastic film on which a pigment is dispersed, or a metal laminated or This includes vapor-deposited paper or the above plastic film.

Preferred substrates include a polyethylene terephthalate film, a polycarbonate film, an aluminum plate, a steel plate and the like, and further, an aluminum plate or a steel plate on which a lipophilic plastic film is laminated.

The preferred aluminum plate used as the support in the lithographic printing plate according to the present invention is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of a different element. Is coated with an oil-based ink receptive polymer compound, or
An oil-based ink receptive plastic is laminated. The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of the foreign element in the alloy is at most 10% by weight or less. However, as the aluminum plate applied to the present invention, an aluminum plate of a conventionally known and used material can be appropriately used.

It is preferable to roughen the surface of the aluminum plate before using it. By performing the surface roughening treatment, when the oil-based ink receiving layer containing an organic polymer is applied on the substrate, the adhesiveness between the substrate and the oil-based ink receiving layer can be easily secured. The roughening process will be described sequentially. Prior to the surface-roughening treatment, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution for removing rolling oil on the surface of the aluminum substrate is performed.

The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening the surface, a method of electrochemically dissolving and roughening the surface, and a method of chemically roughening the surface. Is generally employed.
Known methods such as a ball polishing method, a brush polishing method, a blast polishing method, and a buff polishing method can be used as the mechanical surface roughening method. As a chemical surface roughening method, a method of immersing in a saturated aqueous solution of an aluminum salt of a mineral acid as described in JP-A-54-31187 is suitable. Further, as an electrochemical surface roughening method, there is a method of carrying out an alternating current or a direct current in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Also, an electrolytic surface roughening method using a mixed acid as disclosed in JP-A-54-63902 can be used. The surface roughening by the above-mentioned method is performed when the center line surface roughness (Ha) of the surface of the aluminum plate is 0.3 to
It is preferable that the coating be performed within a range of 1.0 μm.

The roughened aluminum plate is subjected to an alkali etching treatment using an aqueous solution of potassium hydroxide or sodium hydroxide, if necessary, and further subjected to a neutralization treatment. Is anodized. As the electrolyte used for the anodic oxidation treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. Generally, sulfuric acid, hydrochloric acid, oxalic acid,
Chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of the electrolyte.
The anodizing treatment conditions vary depending on the electrolyte used and cannot be specified unconditionally. However, in general, the concentration of the electrolyte is 1 to 80% by weight, the solution temperature is 5 to 70 ° C., and the current density is 5 to 70%.
60A / dm ² , voltage 1-100V, electrolysis time 10 seconds-5
A range of minutes is appropriate. The amount of the oxide film formed is preferably from 1.0 to 5.0 g / m ² , particularly preferably from 1.5 to 4.0 g / m ² .

When a nonconductive material such as polyester is used for the substrate of the present invention, it is preferable to provide an antistatic layer on the oil-based ink-receiving layer side or on the opposite side or on both sides of the substrate. As the antistatic layer, a polymer layer in which metal oxide fine particles and a matting agent are dispersed can be used.

Materials of the metal oxide particles used for the antistatic layer include ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ ,
Examples include In ₂ O ₃ , MgO, BaO, MoO ₃ , V ₂ O ₅ , composite oxides thereof, and / or metal oxides further containing different atoms. These may be used alone or as a mixture. As metal oxides, ZnO, SnO ₂ , Al ₂ O ₃ , Ti
O ₂ , In ₂ O ₃ , and MgO are preferred. Examples of containing a small amount of hetero atoms include Al, In, and S
Sb respect nO _2, Nb or a halogen element, an In ₂
O ₃ may be doped with 30 mol% or less, preferably 10 mol% or less of different atoms such as Sn. Metal oxide particles are present in the antistatic layer
Preferably, it is contained in the range of up to 90% by weight. The average particle diameter of the metal oxide particles that can be used in the antistatic layer is preferably in the range of 0.001 to 0.5 μm. Here, the average particle diameter is a value including not only the primary particle diameter of the metal oxide particles but also the particle diameter of the higher-order structure.

The matting agent that can be used in the antistatic layer preferably has an average particle size of 0.5 to 20 μm,
More preferably, inorganic or organic particles having an average particle size of 1.0 to 15 μm are exemplified. Examples of the inorganic particles include metal oxides such as silicon oxide, aluminum oxide, titanium oxide, and zinc oxide, and metal salts such as calcium carbonate, barium sulfate, barium titanate, and strontium titanate. Examples of the organic particles include cross-linked particles of polymethyl methacrylate, polystyrene, polyolefin, and a copolymer thereof. The matting agent is preferably contained in the antistatic layer in the range of 1 to 30% by weight.

Examples of the polymer which can be used in the antistatic layer include proteins such as gelatin and casein, cellulose compounds such as carboxymethylcellulose, hydroxyethylcellulose, acetylcellulose, diacetylcellulose and triacetylcellulose, dextran, agar and sodium alginate. , Sugars such as starch derivatives, polyvinyl alcohol, polyvinyl acetate, polyacrylate, polymethacrylate, polystyrene, polyacrylamide, polyvinylpyrrolidone,
Examples include synthetic polymers such as polyester, polyvinyl chloride, polyacrylic acid, and polymethacrylic acid. The polymer is preferably contained in the antistatic layer in a range of 10 to 90% by weight.

The substrate used in the present invention preferably has a maximum roughness depth (Rt) of at least 1.2 μm or more from the viewpoint of preventing blocking. Of the lithographic printing plate precursor according to the present invention preferably has a dynamic friction coefficient (μk) of 2.6 or less when sliding on the surface of the lithographic printing plate precursor of the present invention. The thickness of the substrate used in the present invention is about 0.05 mm.
About 0.6 mm, preferably 0.1 mm to 0.4 mm, particularly preferably 0.15 mm to 0.3 mm.

The lithographic printing plate precursor to which the printing method of the present invention can be applied has the above-described configuration. Next, an image recording process and a printing process of the lithographic printing plate precursor will be sequentially described. [Image recording step] In a lithographic printing plate precursor capable of recording a heat-sensitive image with a laser beam, which is a typical example of a lithographic printing plate applicable to the method of the present invention, the laser light energy used for recording is adjusted according to the present invention. The light-to-heat conversion material contained in the lithographic printing plate precursor absorbs and converts it into heat energy. Due to the action of this heat, chemical reactions and physical changes such as combustion, melting, decomposition, vaporization, explosion, etc. are caused in the laser exposure part of the lithographic printing plate precursor, and as a result, the hydrophilic layer is removed from the lower layer. Or it can be removed. In the present invention, since the hydrophilic layer is very thin, removal from the lower layer is easy.

In the present invention, a laser beam is used to expose the lithographic printing plate precursor. The laser to be used is not particularly limited as long as the hydrophilic layer is removed, or provided that it gives an exposure amount necessary to be in a state where the hydrophilic layer can be removed, and a gas laser such as an Ar laser or a carbon dioxide gas laser is used. A solid-state laser such as a YAG laser and a semiconductor laser can be used. Usually 50m output
A laser of W class or higher is required. Semiconductor lasers and semiconductor-excited solid-state lasers (such as YAG lasers) are preferably used in terms of practicality such as maintainability and price. The recording wavelength of these lasers is in the infrared wavelength region, and an oscillation wavelength of 800 nm to 1100 nm is often used. Exposure can also be performed using an imaging device described in JP-A-6-186750.

[Development and Printing Steps] In the lithographic printing plate precursor exposed by the above method, the hydrophilic layer in the laser-exposed area (image area) may be removed during laser exposure. After the laser exposure, the hydrophilic layer in the laser-exposed area (image area) is removed to expose the oil-based ink-receiving layer. Removal of the hydrophilic layer of the laser exposure portion, for example, suction, injection of compressed gas or compressed liquid, pressure bonding and peeling of the adhesive sheet or in the presence or absence of a processing liquid, such as a developing pad or a developing brush This is performed by rubbing the plate surface with a rubbing member. The treatment liquid used in the present invention is preferably water or an aqueous solution containing water as a main component from the viewpoints of safety, flammability, and maintaining hydrophilicity on the surface of the hydrophilic layer, and is simply water (tap water, pure water, An aqueous solution of a surfactant (anionic, cationic, nonionic) or the like can be used. Further, the treatment liquid may include an alkaline agent (for example, sodium carbonate, triethanolamine, diethanolamine, sodium hydroxide, silicates, etc.) or an acid agent (for example, phosphoric acid, phosphorous acid, metaphosphoric acid, pyrophosphoric acid, oxalic acid, etc.). Acids, malic acid, tartaric acid, boric acid, amino acids, etc.) and known antifoaming agents and preservatives can also be used. The temperature of the treatment liquid can be any temperature, but is preferably from 10C to 50C. The removal of the hydrophilic layer in the laser-exposed area can be performed, for example, by mounting the lithographic printing plate precursor after laser exposure on a plate cylinder of a printing press without applying any treatment, and then, on the printing press, applying the emulsion ink to the plate. It is also possible to perform so-called on-press development that is performed by supplying. Further, the lithographic printing method of the present invention includes:
It is preferable to use an offset type lithographic printing press equipped with a known inking device.

In the method of the present invention, when a lithographic printing plate on which an image is recorded is mounted on a printing press and printing is started using emulsion ink, the hydrophilic component of the emulsion ink adheres to the thin film hydrophilic layer exposed on the surface. Then, it becomes an ink-repellent area (non-image area). Further, the exposed oil-based ink-receiving layer forms an ink-philic region (image area), and the oil-based ink component in the emulsion ink is deposited on the oil-based ink-receiving layer, and printing is started.

[0076]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited to these examples. (Example 1) [Preparation of aluminum substrate] In 99.5% by weight of aluminum, 0.01% by weight of copper, 0.03% by weight of titanium, 0.3% by weight of iron, and 0.1% by weight of silicon. JIS contained
A1050 aluminum plate of 0.24 mm in thickness was rolled with 400 mesh pumice stone (manufactured by Kyoritsu Ceramics).
Weight percent aqueous suspension and a rotating nylon brush (6,10-
(Nylon) and the surface was grained, and then washed well with water. This was immersed in a 15% by weight aqueous sodium hydroxide solution (containing 4.5% by weight of aluminum), etched so that the amount of aluminum dissolved was 5 g / m ² , and washed with running water. Further, the mixture was neutralized with 1% by weight of nitric acid and then in an aqueous solution of 0.7% by weight of nitric acid (containing 0.5% by weight of aluminum), the voltage at the time of anode was 10.5 volts and the voltage at the time of cathode was 9.3.
Electrolytic rough surface with an anode electric quantity of 160 coulomb / dm ² using a rectangular wave alternating waveform voltage of volts (current ratio r = 0.90, current waveform described in Examples of Japanese Patent Publication No. 58-5796). Treatment. After washing with water, 10% by weight at 35 ° C
After being immersed in an aqueous solution of sodium hydroxide and etched so that the amount of aluminum dissolved was 1 g / m ² , the substrate was washed with water. Next, it was immersed in a 30% by weight aqueous sulfuric acid solution at 50 ° C., desmutted, and washed with water.

Further, a porous anodic oxide film was formed in a 20% by weight aqueous sulfuric acid solution (containing 0.8% by weight of aluminum) at 35 ° C. using a direct current. That is, electrolysis was performed at a current density of 13 A / dm ² , and the anodic oxide film weight was adjusted to 2.7 g / m ² by adjusting the electrolysis time. The support was washed with water, immersed in a 0.2% by weight aqueous solution of sodium silicate at 70 ° C. for 30 seconds, washed with water and dried. The aluminum substrate obtained as described above had a reflection density of 0.30 and a center line average roughness of 0.58 μm as measured by a Macbeth RD920 reflection densitometer.

[Formation of Oil-Based Ink-Receiving Layer] (Preparation of Carbon Black Dispersion) The following mixture was dispersed for 30 minutes using a paint shaker, and the glass beads were filtered off to prepare a carbon black dispersion. -Carbon black (MA100 manufactured by Mitsubishi Chemical Corporation) 4.0 g-Solsperse S20000 (manufactured by ICI) 0.27 g-Solsperse S12000 (manufactured by ICI) 0.22 g-Propylene glycol monomethyl ether 10 g-Methyl ethyl ketone 10 g-Glass beads 120 g

The following coating solution was applied on the aluminum substrate and dried by heating (120 ° C., 1 minute) to form an oil-based ink-receiving layer having a dry weight of 2 g / m ² . (Oil-based ink receiving layer coating liquid 1) 30 g of the above carbon black dispersion liquid 5 g of a copolymer having a molar ratio of methyl methacrylate / methyl acrylate / hydroxyethyl methacrylate = 65/20/15 = polyurethane resin 5 g (diphenylmethane) Diisocyanate / 2,2-dihydroxymethyl-1-propionic acid / polypropylene glycol (Mw 1000) = condensation reaction product in a molar ratio of 50/30/20) ・ of titanium diisopropoxide bis (2,4-pentadionate) 75% isopropanol solution (AKT855 manufactured by Chisso Corporation) 1 g ・ Propylene glycol monomethyl ether 40 g ・ Methyl ethyl ketone 50 g

[Formation of Thin-Film Hydrophilic Layer] Then, silicon oxide was deposited on the oil-based ink-receiving layer using a batch-type sputter film-forming apparatus (CFS-10-EP70 manufactured by Shibaura Eletech Co., Ltd.) to a thickness of 100 nm under the following conditions. A film was formed to form a hydrophilic layer. Target material: silicon oxide Atmosphere: argon Film formation pressure: 5 mtorr Power: RF1 kW (power supply is JRF- manufactured by JEOL Ltd.)
3000)

Before the film formation, the surface of the oil-based ink receiving layer was glow-treated under the following conditions. Atmosphere: Argon Processing pressure: 5.0 mtorr Power: RF3kW (Power supply is JRF manufactured by JEOL
-3000) Time: 2.5 minutes

[Formation of Overcoat Layer] Then, the following coating solution was applied on the hydrophilic layer and dried by heating (100
C. for 2 minutes) to obtain a dry coating weight of 0.1 g / m ^2.
Was formed to obtain a lithographic printing plate precursor of Example 1. (Coating solution 1 for overcoat layer)-1 g of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., PVA204)-0.025 g of polyoxyethylene nonylphenyl ether-39 g of water

[Image Recording] From the hydrophilic layer side of the lithographic printing plate precursor described above, a 40 W trend setter (40
Using a 830 nm W semiconductor laser mounted on a plate setter), image exposure was performed at an energy of 300 mJ / cm ² . Then, the surface of the lithographic printing plate precursor subjected to image exposure was rubbed using a developing pad containing a 10% by volume aqueous solution of EU-3 (manufactured by Fuji Photo Film Co., Ltd.),
The overcoat layer and the hydrophilic layer in the laser-exposed area were removed, and in the image area, the oil-based ink-receiving layer was exposed to form an image.

[Printing Evaluation] Next, the lithographic printing plate was mounted on a printing machine (Heidelberg SOR-M) and printed with an emulsion ink having the following composition. A good printed product without missing parts was obtained. (Emulsion Ink Composition 1) [Preparation of Emulsion Ink] (1) Preparation of Varnish (Hereinafter, parts are by weight.) Varnish A: Maleated petroleum resin (Neopolymer 120: Nippon Oil Co., Ltd.) 47 Part Spindle oil 53 parts Gel varnish B: Rosin-modified phenolic resin (Tamanol 354: manufactured by Arakawa Chemical Industry Co., Ltd.) 34 parts Machine oil 31 parts Spindle oil 31 parts Aluminum stearate 4 parts Varnish C: Gilsonite 25 parts Machine oil 75 parts

(2) Preparation of oil-based ink component: ・ 14 parts of carbon black ・ 5 parts of calcium carbonate (white glossy flower DD: manufactured by Shiraishi Industry Co., Ltd.) ・ 27 parts of varnish A ・ 7 parts of gel varnish B ・ 11 parts of varnish C -Linseed oil 4 parts-Machine oil 6 parts-Spindle oil 24 parts-Cyanine blue 1 part

(3) Preparation of hydrophilic component:-10 parts of purified water-55 parts of propylene glycol-34 parts of glycerin-Surfactant (polyoxyethylene alkyl phenyl ether, Liponox NCE: manufactured by Lion Oil & Fat Co., Ltd.) Department

100 parts by weight of the oil-based ink component of (2) and 70 parts by weight of the hydrophilic component of (3) were mixed by stirring.
An O-type emulsion ink was prepared.

Example 2 Printing was performed using an emulsion ink (composition 1) in the same manner as in Example 1 except that the lithographic printing plate precursor exposed to laser was mounted on a printing machine without any treatment. In the initial stage of printing, the overcoat layer and the hydrophilic layer in the laser-exposed area are promptly removed from the plate surface on the printing press, and the oil-based ink-receiving layer is exposed in the image area, and the non-image area of 20,000 sheets is exposed. Thus, a good printed matter free of stains and image portions was not obtained.

(Example 3) [Preparation of substrate] Corona treatment was applied to both surfaces of polyethylene terephthalate having a thickness of 180 μm, and
Apply the following coating solution and heat dry (180 ° C, 30 seconds)
Then, an antistatic layer having a dry film thickness of 0.2 g / m ² was formed. (Antistatic layer coating liquid) Acrylic resin aqueous dispersion (Julima ET-410, solid content: 20% by weight, manufactured by Nippon Pure Chemical Co., Ltd.) 20 g Tin water-antimony oxide aqueous dispersion (average particle diameter: 0.1%) 1 g, 17% by weight) 36 g Polyoxyethylene nonylphenyl ether (Nonipol 100, manufactured by Sanyo Chemical Industries, Ltd.) 0.6 g Aqueous sodium salt of alkyl diphenyl ether disulfonate (Sandet BL, concentration 40% by weight, Sanyo Chemical Industries ( Melamine compound (Sumitec Resin M-3, active ingredient concentration 80% by weight, manufactured by Sumitomo Chemical Co., Ltd.) 0.2 g Polymethacrylic acid resin particles (MX-500, average particle size) 5 μm, Soken Chemical Co., Ltd.) 0.2 g ・ Water 42.4 g

[Preparation of Oil-based Ink-Receiving Layer] The following oil-based ink-receiving layer coating solution was applied onto the above-mentioned polyethylene terephthalate undercoated with an antistatic layer, and dried by heating (100%).
C., 1 minute) to form an oil-based ink-receiving layer having a dry coating amount of 0.5 g / m ² . (Oil-based ink-receptive layer coating solution 2) Epoxy resin (Epicoat 1010, manufactured by Yuka Shell Epoxy Co., Ltd.) 5 g γ-butyrolactone 9.5 g Methyl lactate 3 g Methyl ethyl ketone 22.5 g Propylene glycol monomethyl ether 22 g

[Formation of Thin-Film Hydrophilic Layer] Aluminum oxide was deposited to form a hydrophilic layer in the same manner as in the formation of the hydrophilic layer in Example 1, except that the target material was changed to aluminum oxide. [Formation of overcoat layer] Next, the following coating solution was applied on the hydrophilic layer and dried by heating (100 ° C, 2 minutes) to form an overcoat layer having a dry coating weight of 0.6 g / m ^2. Then, a lithographic printing plate precursor was obtained. (Overcoat layer coating solution 2) ・ Polyacrylic acid (Wako Pure Chemical Industries, Ltd., weight average molecular weight 25,000) 1 g ・ (I-32) infrared absorbing dye 0.2 g ・ Polyoxyethylene nonylphenyl ate Tail 0.025g ・ Water 19g

[Image recording] The above lithographic printing plate precursor was subjected to laser image exposure and treatment in the same manner as in Example 1 to remove the overcoat layer and the hydrophilic layer in the laser-exposed area. The ink-receiving layer was exposed to form an image. [Printing Evaluation] Then, when the above lithographic printing plate was printed in the same manner as in Example 1, 20,000 sheets of good printed matter free of stains in the non-image area and exudation of the image area were obtained.

Example 4 Printing was performed using an emulsion ink (composition 1) in the same manner as in Example 3 except that the lithographic printing plate precursor exposed to laser was mounted on a printing machine without any treatment. In the initial stage of printing, the overcoat layer and the hydrophilic layer in the laser-exposed area are promptly removed from the plate surface on a printing press, and in the image portion,
The oil-based ink receptive layer was exposed, and 20,000 good prints were obtained without stains in the non-image area and no bleeding in the image area.

(Examples 5 to 8) Printing was carried out in the same manner as in Examples 1 to 4 except that an emulsion ink having the following composition was used. Good printed matter without soaking was obtained. (Emulsion Ink Composition 2) [Preparation of Emulsion Ink] (1) Preparation of Varnish (Hereinafter, parts are by weight.) By the following formulation, gelation was performed by heating at 200 ° C. for 1 hour to obtain a gel varnish D.・ Rosin-modified phenolic resin (Hitanol 270T: manufactured by Hitachi Chemical Co., Ltd.) 42 parts ・ Low viscosity linseed oil polymerization varnish (2 poise) 30 parts ・ Spindle oil 27 parts ・ Ethyl acetoaceto aluminum diisopropylate 1 part

(2) Preparation of oil-based ink component:-Gel varnish D 66 parts-Phthalocyanine blue 20 parts-Low viscosity linseed oil polymerization varnish (2 poise) 5 parts-Polyethylene wax compound 3 parts-Cobalt dryer 1 part-Spindle oil 5 Department

(3) Preparation of hydrophilic component: 100 parts of ethylene glycol 100 parts by weight of oily ink component of item (2) and 45 parts by weight of hydrophilic component of item (3) are mixed with stirring to form a W / O type. An emulsion ink was prepared.

(Examples 9 to 14) The printing was evaluated in the same manner as in Example 4 except that the hydrophilic component of the emulsion ink was changed to the composition shown in Table 1 below. The hydrophilic layer of the laser-exposed area is promptly removed from the printing plate on the printing press, and the oil-based ink-receptive layer is exposed in the image area, so that 20,000 sheets of non-image area are not stained and the image area is not soaked. Good printed matter was obtained.

[0098]

[Table 1]

Comparative Example 1 Aqualess Echo Ink LZ (Toyo Ink Manufacturing Co., Ltd.), a lithographic printing ink that does not require dampening solution
The printing evaluation was performed in the same manner as in Example 3 except that the above was used as the printing ink. As a result, the non-image area was stained, and a good printed matter could not be obtained. As described above, when printing is performed with an oil-based ink without using an emulsion ink, the hydrophilic layer cannot sufficiently repel the ink, the non-image area is stained, and a good printed matter can be obtained. Did not.

(Comparative Example 2) An ordinary PS plate having an aluminum surface as a non-image portion (V, manufactured by Fuji Photo Film Co., Ltd.)
S) was image-exposed, and a lithographic printing plate obtained by carrying out genuine development processing was printed using an emulsion ink (composition 1) in the same manner as in Example 1.
Since the surface area was large due to the effect of the surface roughening / hydrophilization treatment, the hydrophilic component in the emulsion ink did not sufficiently reach the non-image area, and a uniform hydrophilic film was not formed. Even when used,
Background stains occurred in the non-image area, and good printed matter could not be obtained.

[0101]

The constitution of the lithographic printing method of the present invention, that is, a lithographic printing plate having a thin film hydrophilic layer having a surface containing a metal oxide in a non-image area is prepared by adding water and / or water to an oil-based ink component. The method of printing using an emulsion ink emulsified by adding a hydrophilic component containing a polyhydric alcohol as a main component makes it possible to easily obtain a stable, high-quality printed matter.

Continued on the front page F term (reference) 2H084 AA14 AE05 CC06 2H096 AA06 CA03 HA30 2H113 AA02 AA03 BA06 BC00 BC02 DA03 DA07 DA42 DA43 DA48 DA49 DA53 DA54 DA56 DA57 DA58 DA60 DA62 DA64 2H114 AA05 AA22 AA24 DA01 DA04 DA05 DA08 DA52 DA53 DA55 DA56 DA57 DA59 DA60 DA62 EA01 EA02 EA08

Claims (1)

[Claims] An image is recorded on a lithographic printing plate precursor to form a non-image portion region composed of a thin film hydrophilic layer having a surface containing a metal oxide, and thereafter, water and / or water is added to the oil-based ink component. A lithographic printing method, characterized in that a lithographic printing method is characterized in that a hydrophilic component containing a polyhydric alcohol as a main component is added, and printing is performed using an emulsion ink obtained by emulsification.