JP2009172855A - Manufacturing method of lithographic printing plate, exposing method of lithographic printing plate material and printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process-less plate, the image visibility of which is improved through exposure and which is excellent in print durability. <P>SOLUTION: This manufacturing method of a lithographic printing plate has a plurality of processes for exposing a support and a lithographic printing plate material having a heatsensitive recording layer provided on the support and including hot weld particles or heatsensitive hydrophobic polymer particles. In this case, at least one process to expose the lithographic printing plate material is one process for heating the surface of the lithographic printing plate up to 120°C or more through the exposure with infrared rays. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lithographic printing plate manufacturing method, a lithographic printing plate material exposure method, and a printing method.

  In the printing industry, with the digitization of print data, there is a demand for CTP (computer-to-plate) technology that is inexpensive, easy to handle, and has the same printability as the PS plate. In recent years, in order to reduce the burden on the global environment, there is an increasing expectation for a so-called processless CTP printing plate that does not require wet development with a special chemical.

  Infrared laser recording is a promising image forming method for processless printing plates. There are three types of recording methods: an ablation type, a thermal fusion transfer type, and a thermal fusion image layer development type. Exists. Among them, the heat fusion image layer on-machine development type having an image layer containing heat fusible fine particles or heat fusible fine particles is considered to be a mainstream method in the future because no ablation defects occur in exposure. (See Patent Documents 1 and 2).

  In the industry, after image exposure, an operation called plate inspection is performed to confirm whether a desired image is recorded. For this reason, an image contrast that can be easily visually confirmed is required. In the case of a general printing plate, it is possible to form a contrast relatively easily by adding dyes / pigments etc. to the image layer and removing it by development processing. However, in the case of an on-press development type printing plate, It is necessary to form contrast at the stage of exposure. In the on-press development plate using heat-meltable fine particles, a technique for providing contrast by changing the scattered light has been proposed (see Patent Document 3).

As a technique for direct writing using an infrared laser, a method of irradiating a laser while heating and holding the original plate at 40 to 110 ° C. has been proposed (see Patent Document 4). This technology includes infrared irradiation as a heating means, but the purpose is to reduce the energy loss of the laser beam and the energy of the laser beam, and there is no description about the improvement of visible image quality.
JP-A-9-123387 JP-A-9-123388 JP 2006-31275 A JP-A-11-58666

  An object of the present invention is to provide a processless plate having improved visibility in exposure. The second object of the present invention is to provide a processless plate having on-press development suitability and excellent printing durability.

The above object of the present invention has been achieved by the following constitution.
1.
A lithographic printing plate comprising a plurality of steps of exposing a lithographic printing plate material having a support and a heat-sensitive recording layer containing heat-fused fine particles or heat-sensitive hydrophobic polymer particles provided on the support. Production method.
2.
2. The method for producing a lithographic printing plate as described in 1 above, wherein at least one of the steps of exposing the lithographic printing plate material heats the surface of the lithographic printing plate material to 120 ° C. or more during infrared exposure.
3.
Item 1 or 2 above, wherein the plurality of exposure steps include a first step of exposing the entire surface of the lithographic printing plate material with infrared rays and a second step of imagewise exposure with infrared laser light thereafter. The manufacturing method of the lithographic printing plate of description.
4).
Item 1 or 2, wherein the plurality of exposure steps include a first step of imagewise exposure with infrared laser light and a second step of exposing the entire surface of the lithographic printing plate material with infrared rays thereafter. The manufacturing method of the lithographic printing plate of description.
5.
An exposure method for a lithographic printing plate material, wherein the first exposure is performed by infrared irradiation, and the second exposure is an imagewise exposure using infrared laser light.
6).
An exposure method for a lithographic printing plate material, wherein the first exposure is imagewise exposure using infrared laser light, and the second exposure is exposure by infrared irradiation.
7).
An exposure method for a lithographic printing plate material, wherein the first exposure and the second exposure are performed by imagewise exposure using infrared laser light.
8).
8. The exposure method for a lithographic printing plate material according to any one of 5 to 7, wherein the interval between the first exposure and the second exposure is 0.01 to 5 seconds.
9.
A plurality of steps of exposing the lithographic printing plate material having a support and a heat-sensitive recording layer containing heat-bonding fine particles or heat-sensitive hydrophobic polymer particles provided on the support, any one of items 5 to 8 above. An exposure method for a lithographic printing plate material comprising the exposure method described in 1.
10.
5. A printing method comprising printing after development on a printing press using a lithographic printing plate obtained by the method for producing a lithographic printing plate according to any one of 1 to 4 above.

  According to the present invention, it is possible to provide a processless plate with improved visibility in exposure. The obtained processless plate is excellent in printing durability.

  Hereinafter, the present invention will be described in more detail.

  The lithographic printing plate material (hereinafter also referred to as printing plate material) according to the present invention has a heat-sensitive recording layer (hereinafter also referred to as an image forming layer) containing heat-fused fine particles or heat-sensitive hydrophobic polymer particles on a support.

<Heat-bonding fine particles>
The heat-sealable fine particles of the present invention are particles formed of a material that has a low viscosity when melted, and is generally classified as a wax, among thermoplastic materials. The physical properties are preferably a softening point of 40 to 120 ° C. and a melting point of 60 to 150 ° C., more preferably a softening point of 40 to 100 ° C. and a melting point of 60 to 120 ° C. When the melting point is in this range, both storage stability and ink deposition sensitivity can be satisfied.

  Usable materials include paraffin, polyolefin, polyethylene wax, microcrystalline wax, fatty acid wax and the like. These have a molecular weight of about 800 to 10,000. In order to facilitate emulsification, these waxes can be oxidized to introduce polar groups such as hydroxyl groups (hydroxyl groups), ester groups, carboxyl groups, aldehyde groups, peroxide groups and the like.

  Furthermore, in order to lower the softening point and improve workability, these waxes are treated with stearoamide, linolenic amide, lauryl amide, myristamide, hardened beef fatty acid amide, palmitoamide, oleic acid amide, rice sugar fatty acid amide, palm It is also possible to add fatty acid amides or methylolated products of these fatty acid amides, methylene bisstellaramide, ethylene bisstellaramide and the like. Coumarone-indene resin, rosin-modified phenol resin, terpene-modified phenol resin, xylene resin, ketone resin, acrylic resin, ionomer, and copolymers of these resins can also be used.

  Among these, it is preferable to contain any of polyethylene, microcrystalline, fatty acid ester, and fatty acid. Since these materials have a relatively low melting point and a low melt viscosity, high-sensitivity image formation can be performed. Further, since these materials have lubricity, damage when a shearing force is applied to the surface of the printing plate material is reduced, and resistance to printing stains due to scratches is improved.

  The heat fusion fine particles are preferably dispersible in water, and the average particle diameter is preferably 0.01 to 10 μm, more preferably 0.1 μm, from the viewpoint of on-press developability and resolution. ~ 3 μm.

  Further, the composition of the heat fusion fine particles may vary continuously between the inside and the surface layer, or may be coated with a different material.

  As a coating method, a known microcapsule forming method, a sol-gel method, or the like can be used.

  In a preferred embodiment, the image forming layer of the present invention contains heat-fused fine particles in a microencapsulated form.

  As content of the heat sealing | fusion fine particle in a layer, 1-90 mass% of the whole layer is preferable, and 5-80 mass% is still more preferable.

  Examples of the heat-sealing fine particles used in the present invention include thermoplastic hydrophobic polymer particles, and there is no specific upper limit for the softening temperature of the polymer particles, but the temperature is the decomposition of the polymer particles. It is preferable that the temperature is lower than that. The weight average molecular weight (Mw) of the polymer is preferably in the range of 10,000 to 1,000,000.

  Specific examples of the polymer constituting the polymer particles include diene (co) polymers such as polypropylene, polybutadiene, polyisoprene, and ethylene-butadiene copolymer, styrene-butadiene copolymer, and methyl methacrylate. -Synthetic rubbers such as butadiene copolymer, acrylonitrile-butadiene copolymer, polymethyl methacrylate, methyl methacrylate- (2-ethylhexyl acrylate) copolymer, methyl methacrylate-methacrylic acid copolymer, methyl acrylate- (N- (Methylolacrylamide) copolymer, (meth) acrylic acid ester such as polyacrylonitrile, (meth) acrylic acid (co) polymer, polyvinyl acetate, vinyl acetate-vinyl propionate copolymer, vinyl acetate-ethylene copolymer Vinyl esters such as Co) polymers, vinyl acetate - (2-ethylhexyl acrylate) copolymers, polyvinyl chloride, polyvinylidene chloride, polystyrene and copolymers thereof. Of these, (meth) acrylic acid esters, (meth) acrylic acid (co) polymers, vinyl ester (co) polymers, polystyrene, and synthetic rubbers are preferably used.

  The polymer particles may be composed of a polymer polymer polymerized by any known method such as emulsion polymerization, suspension polymerization, solution polymerization, and gas phase polymerization. As a method of microparticulating a polymer polymer polymerized by a solution polymerization method or a gas phase polymerization method, a method of spraying a solution in an organic solvent of the polymer polymer into an inert gas and drying to form particles, Examples thereof include a method in which a high molecular weight polymer is dissolved in a water-immiscible organic solvent, this solution is dispersed in water or an aqueous medium, and the organic solvent is distilled to form fine particles. In any of the methods, a surfactant or a surfactant such as sodium lauryl sulfate, sodium dodecylbenzenesulfonate, polyethylene glycol, or a water-soluble solution such as polyvinyl alcohol is used as a dispersing agent or stabilizer during polymerization or micronization as necessary. Resin may be used.

  The heat-sealing fine particles are preferably dispersible in water, and the average particle diameter is preferably 0.01 to 10 μm, more preferably 0.1 to 10 μm from the viewpoint of on-press developability and resolution. ~ 3 μm.

  The heat-fusible particles may be continuously changed in composition between the inside and the surface layer, or may be coated with different materials. As a coating method, a known microcapsule forming method, a sol-gel method, or the like can be used.

  In a particularly preferred embodiment, the image forming layer according to the present invention contains heat-fusible particles in a microencapsulated form.

  Examples of the microcapsule include microcapsules enclosing a hydrophobic material described in JP-A-2002-2135 and 2002-19317.

  The microcapsules preferably have an average diameter of 0.1 to 10 μm, more preferably 0.3 to 5 μm, and still more preferably 0.5 to 3 μm. The thickness of the wall of the microcapsule is preferably 1/100 to 1/5 of the diameter, and more preferably 1/50 to 1/10. The content of the microcapsules is 5 to 100% by mass of the entire image forming layer, preferably 20 to 95% by mass, and more preferably 40 to 90% by mass.

  Known materials and methods can be used as the material for the wall of the microcapsule and the method for producing the microcapsule. For example, publicly known materials and methods described in “New edition microcapsules, production method, properties, and application” (written by Tamotsu Kondo, Masumi Koishi: published by Sankyo Publishing Co., Ltd.) or cited documents can be used.

<Heat-sensitive hydrophobic polymer>
The heat-sensitive hydrophobic polymer particles according to the present invention are those in which a water-insoluble hydrophobic polymer is dispersed as fine particles in a water-soluble dispersion medium. As the dispersion state, the polymer is emulsified in a dispersion medium, emulsion-polymerized, micelle-dispersed, or partly hydrophilic in the polymer molecule and the molecular chain itself is molecularly dispersed. Any of these may be used. As for polymer latex, “Synthetic resin emulsion (Hiraku Okuda, Hiroshi Inagaki: Published by Kobunshi Publishing (1978))”, “Application of synthetic latex (Takaaki Sugimura, Ikuo Kataoka, Junichi Suzuki, Keiji Kasahara, Takashi Published in Molecular Publications (1993)), “Synthetic Latex Chemistry (written by Soichi Muroi: published by High Polymers Publication (1970))” and the like.

  The average particle diameter of the dispersed particles is preferably in the range of 1 to 50,000 nm, more preferably about 5 to 1,000 nm. The particle size distribution of the dispersed particles is not particularly limited, and may have a wide particle size distribution or a monodispersed particle size distribution.

  The polymer latex of the present invention may be a so-called core / shell type latex other than a normal polymer latex having a uniform structure. In this case, it may be preferable to change the glass transition temperature (Tg) between the core and the shell.

  The Tg of the polymer latex used for the binder of the present invention is −30 to 40 ° C. The minimum film forming temperature (MFT) of the polymer latex is preferably −30 to 90 ° C., more preferably about 0 to 70 ° C. In order to control MFT, a film-forming aid may be added. The film-forming aid, also called a plasticizer, is an organic compound (usually an organic solvent) that lowers the MFT of the polymer latex, and is described, for example, in the aforementioned “Synthetic Latex Chemistry”.

  Examples of the polymer species used in the polymer latex of the present invention include acrylic resins, vinyl acetate resins, polyester resins, polyurethane resins, rubber resins, vinyl chloride resins, vinylidene chloride resins, polyolefin resins, and copolymers thereof. . The polymer may be a linear polymer, a branched polymer, or a crosslinked polymer.

  The polymer may be a so-called homopolymer in which a single monomer is polymerized or a copolymer in which two or more monomers are polymerized. In the case of a copolymer, it may be a random copolymer or a block copolymer. The molecular weight of the polymer is about 5,000 to 1,000,000, preferably about 10,000 to 100,000 in terms of number average molecular weight (Mn). By setting the molecular weight within the above range, both the mechanical strength and the film forming property of the layer can be satisfied.

  Specific examples of the polymer latex used as the binder of the present invention include the following. Latex of methyl methacrylate / ethyl acrylate / methacrylic acid copolymer, latex of methyl methacrylate / 2-ethylhexyl acrylate / styrene / acrylic acid copolymer, latex of styrene / butadiene / acrylic acid copolymer, latex of styrene / butadiene / divinylbenzene / methacrylic acid copolymer , Latex of methyl methacrylate / vinyl chloride / acrylic acid copolymer, latex of vinylidene chloride / ethyl acrylate / acrylonitrile / methacrylic acid copolymer, and the like.

  Such polymers are also commercially available, and the following polymers can be used. For example, as an example of acrylic resin, Sebian A-4635, 46583, 4601 (manufactured by Daicel Chemical Industries), Nipol Lx811, 814, 821, 820, 857 (manufactured by Nippon Zeon Co., Ltd.) and the like; FINETEX ES650, 611 as a polyester resin 675,850 (Dainippon Ink Chemical Co., Ltd.), WD-size, WMS (Eastman Chemical Co., Ltd.), etc .; as polyurethane resin, HYDRAN AP10, 20, 30, 40 (Dainippon Ink Chemical Co., Ltd.), etc .; rubber type LACSTAR 7310K, 3307B, 4700H, 7132C (manufactured by Dainippon Ink & Chemicals), Nipol Lx416, 410, 438C, 2507 (manufactured by Nippon Zeon Co., Ltd.) and the like; G351, 576 (manufactured by Nippon Zeon Co., Ltd.) Etc .; Vinylidide chloride Examples of the resin include L502,513 (manufactured by Asahi Kasei Kogyo Co., Ltd.), Aron D7020,504,5071 (manufactured by Mitsui Toatsu), etc .; Examples of the olefin resin include Chemipearl S120, SA100 (manufactured by Mitsui Petrochemical Co., Ltd.) . These polymers may be used alone or in combination of two or more as required. The content of the polymer latex is preferably 50% by mass or more.

<Multiple exposure>
The present invention is characterized by having a plurality of steps of exposing the printing plate material. That is, (a) image-wise exposure with infrared laser light after image-wise exposure with infrared laser light, and (b) image-wise exposure with infrared laser light and image-wise exposure with infrared light. Thereby, the visible image quality is remarkably improved.

  In addition, it is preferable that the space | interval of the 1st exposure and the 2nd exposure is 0.01 to 5 second, More preferably, it is 0.1 to 2 second.

  In order to make it 0.01 seconds or less, the laser exposure mechanism and the entire surface exposure mechanism must be installed close to each other, which is not practical. On the other hand, if the interval is longer than 5 seconds, the thermal efficiency is deteriorated due to heat radiation or the like.

(Infrared exposure)
Infrared exposure is performed to heat the surface of the printing plate material to 120 ° C. or higher. As a method of irradiating infrared rays, it is preferable to use a ceramic heater, a hollow heater or the like that radiates far infrared rays. The upper limit of the surface temperature of the printing plate material is 250 ° C. By heating the surface of the printing plate material to 120 to 250 ° C., both the visibility and the on-press development suitability can be improved.

(Infrared laser exposure)
The printing plate material according to the present invention preferably forms an image using laser light. Among these, it is particularly preferable to form an image by exposure with a thermal laser. For example, scanning exposure using laser light that emits light in the infrared and / or near infrared region, that is, emits light in the wavelength range of 700 to 1,500 nm is preferable. A gas laser may be used as the laser, but it is particularly preferable to use a semiconductor laser that emits light in the near infrared region.

  As an apparatus suitable for scanning exposure, any apparatus may be used as long as it can form an image on the surface of the printing plate material in accordance with an image signal from a computer using the semiconductor laser.

  Generally, there are the following three methods.

  (1) A method in which the entire surface of the printing plate material is exposed by performing two-dimensional scanning on the printing plate material held by the flat plate-like holding mechanism using one or a plurality of laser beams.

  (2) The printing plate material held along the cylindrical surface inside the fixed cylindrical holding mechanism is used in the circumferential direction of the cylinder (in the main scanning direction) by using one or a plurality of laser beams from the inside of the cylinder. ), The entire surface of the printing plate material is exposed by moving in the direction perpendicular to the circumferential direction (sub-scanning direction).

  (3) A printing plate material held on the surface of a cylindrical drum that rotates about an axis as a rotating body is rotated in the circumferential direction (main scanning direction) by rotating the drum using one or more laser beams from the outside of the cylinder. ), The entire surface of the printing plate material is exposed by moving in the direction perpendicular to the circumferential direction (sub-scanning direction).

  In particular, in an apparatus that performs exposure on a printing apparatus (developing apparatus on a printing press), the exposure method (3) is used.

  In the present invention, in the exposure method (2), the surface of the printing plate material can be raised to 120 ° C. or higher by disposing the ceramic heater or the like at a position that does not interfere with the laser beam.

<Other components>
The image forming layer suitable for image exposure with laser light preferably contains a photothermal conversion agent, and further preferably contains a thermoplastic substance, a water-soluble compound, a pH adjuster, a surfactant and the like.

(Photothermal conversion agent)
The photothermal conversion agent is a material that can convert exposure light into heat to form an image on the image forming layer. Examples of the photothermal conversion agent include the following dyes and pigments.

  Examples of the dye include organic compounds such as cyanine, croconium, polymethine, azurenium, squalium, thiopyrylium, naphthoquinone, and anthraquinone dyes that are general infrared absorbing dyes; phthalocyanine, naphthalocyanine, azo And organic metal complexes such as thioamide, dithiol, and indoaniline dyes.

  Specifically, JP-A-63-139191, JP-A-64-33547, JP-A-1-160683, JP-A-1-280750, JP-A-1-293342, JP-A-2-2074, JP-A-3-26593, Described in 3-30991, 3-34891, 3-36093, 3-36094, 3-36095, 3-42281, 3-97589, 3-103476, etc. The compound of this is mentioned. These can be used alone or in combination of two or more.

  Further, compounds described in JP-A-11-240270, JP-A-11-265062, JP-A-2000-309174, JP-A-2002-49147, JP-A-2001-162965, JP-A-2002-144750, and JP-A-2001-219667 are also included. It can be preferably used.

  Examples of the pigment include carbon, graphite, metal, metal oxide and the like.

  As carbon, it is particularly preferable to use furnace black or acetylene black. The particle size (d50) is preferably 100 nm or less, and more preferably 50 nm or less.

  As the graphite, fine particles having a particle size of 0.5 μm or less, preferably 100 nm or less, more preferably 50 nm or less can be used.

  As the metal, any metal can be used as long as the particle diameter is 0.5 μm or less, preferably 100 nm or less, more preferably 50 nm or less. The shape may be any shape such as a spherical shape, a piece shape, or a needle shape. Colloidal metal fine particles (Ag, Au, etc.) are particularly preferable.

  As the metal oxide, a material that is black in the visible light region, or a material that has conductivity or is a semiconductor can be used.

(Water-soluble compounds)
The image forming layer preferably contains a water-soluble compound.

  The water-soluble compound refers to a compound that dissolves in an amount of 0.1 g or more in 100 g of water at 25 ° C., and preferably a compound that dissolves in an amount of 1 g or more in 100 g of water at 25 ° C.

  Specific examples of the water-soluble compound include the following, but are not limited thereto.

  Glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, and their ether or ester derivatives, polyhydroxys such as glycerin and pentaerythritol, triethanolamine, diethanolamine monoethanolamine, etc. Organic amines and salts thereof, quaternary ammonium salts such as tetraethylammonium bromide, organic sulfonic acids and salts thereof such as toluenesulfonic acid and benzenesulfonic acid, organic phosphonic acids and salts thereof such as phenylphosphonic acid, tartaric acid, oxalic acid, Organic carboxylic acids such as citric acid, apple acid, lactic acid, gluconic acid, amino acids and their salts, phosphates (trisodium phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate) , Guanidine phosphate, etc.), sodium carbonate (carbonate, guanidine carbonate, etc.), other water-soluble organic salts, inorganic salts. Saccharides (monosaccharides, oligosaccharides, etc.), polysaccharides, polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyethylene glycol (PEG), polyvinyl ether, polyacrylic acid, polyacrylate, polyacrylamide, polyvinylpyrrolidone, polystyrene sulfonic acid, Water-soluble polymers such as polystyrene sulfonate are listed. Also, water dispersible latex such as styrene-butadiene copolymer latex, conjugated diene polymer latex of methyl methacrylate-butadiene copolymer, acrylic polymer latex, vinyl polymer latex, and the like.

  The content of the water-soluble compound is 1 to 40% by mass, preferably 5 to 30% by mass, and preferably 10 to 25% by mass with respect to the image forming layer in terms of on-press developability. More preferred.

(PH adjuster)
The image forming layer may contain an acid (phosphoric acid, acetic acid, etc.) or an alkali (sodium hydroxide, silicate, phosphate, etc.) for pH adjustment.

(Surfactant)
In addition, the coating solution used for coating the hydrophilic layer can contain a water-soluble surfactant for the purpose of improving the coating property, and a silicon-based or fluorine-based surfactant is used. However, it is particularly preferable to use a surfactant containing silicon element because there is no fear of causing printing stains. The content of the surfactant is preferably 0.01 to 3% by mass, more preferably 0.03 to 1% by mass of the entire hydrophilic layer (solid content as the coating solution).

The amount with the image forming layer, image visibility, it is preferable that in view of the sensitivity is 0.1 to 3.0 g / m ^2, more preferably from 0.3 to 1.5 g / m ^2.

(On-press development suitability)
In a preferred embodiment, the image forming layer according to the present invention is an image forming layer capable of on-press development or water development. An on-machine developable image forming layer is printed after being exposed to an image, without being subjected to a development process, when it is subjected to a printing process, i.e., with dampening water or dampening water and printing ink in a printing preparation stage. It refers to an image forming layer in which a portion of the image forming layer that becomes a non-image portion is sometimes removed to form a printable image.

<Support>
The support for the printing plate material of the present invention is preferably a substrate having a hydrophilic surface.

  The base material having a hydrophilic surface is a base material having a surface where the heat-sensitive image-forming layer is removed at the time of printing and can become a non-image portion by being water-receptive. A substrate having a surface layer and a substrate provided with a hydrophilic layer containing a hydrophilic substance can be used.

  As the base material, if the surface shape is within the range specified in the present invention, a known material used as a substrate of a printing plate can be used, for example, a paper treated with a metal plate, a plastic film, a polyolefin or the like. And a composite base material obtained by appropriately laminating the above materials.

  The thickness of the base material is not particularly limited as long as it can be attached to a printing press, but a thickness of 50 to 500 μm is generally easy to handle.

  Among these, a metal plate having a hydrophilic surface is preferably used. Examples of the metal plate include iron, stainless steel, and aluminum. In the present invention, aluminum or an aluminum alloy (hereinafter, both referred to as an aluminum plate) is particularly preferable because of the relationship between specific gravity and rigidity. In addition, a material subjected to any of the known roughening treatment, anodizing treatment, and surface hydrophilization treatment (so-called aluminum grained plate) is more preferable.

  Various aluminum alloys can be used as the base material. For example, an alloy of metal such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel, titanium, sodium, iron, and aluminum can be used.

  Prior to roughening (graining treatment), the aluminum plate used as the base material is preferably subjected to a degreasing treatment in order to remove the rolling oil on the surface. As the degreasing treatment, a degreasing treatment using a solvent such as trichlene or thinner, an emulsion degreasing treatment using an emulsion such as kesilon or triethanol, or the like is used. In addition, an alkaline aqueous solution such as sodium hydroxide can be used for the degreasing treatment. When an alkaline aqueous solution such as sodium hydroxide is used for the degreasing treatment, dirt and oxide film that cannot be removed only by the degreasing treatment can be removed. When an alkaline aqueous solution such as sodium hydroxide is used for the degreasing treatment, smut is generated on the surface of the base material, so that it is immersed in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid, or a mixed acid thereof and subjected to a desmut treatment. It is preferable. Examples of the roughening method include a mechanical method and a method of etching by electrolysis.

The mechanical roughening method used is not particularly limited, but a brush polishing method and a honing polishing method are preferable. The surface roughening by the brush polishing method is, for example, rotating a rotating brush using brush bristles having a diameter of 0.2 to 0.8 mm, and for example, volcanic ash particles having a particle diameter of 10 to 100 μm on water. While supplying the uniformly dispersed slurry, the brush can be pressed. The roughening by honing polishing is performed by, for example, uniformly dispersing volcanic ash particles having a particle diameter of 10 to 100 μm in water, injecting pressure from a nozzle and injecting them obliquely to the surface of the base material. Can do. Also, for example, abrasive particles having a particle size of 10 to 100 μm are applied to the surface of the substrate so as to exist at a density of 2.5 × 10 ³ to 10 × 10 ³ particles / cm ² at intervals of 100 to 200 μm. Roughening can also be performed by laminating the sheets and applying pressure to transfer the rough surface pattern of the sheets.

After roughening by the above-mentioned mechanical roughening method, it is preferable to immerse in an aqueous solution of acid or alkali in order to remove the abrasive that has digged into the surface of the base material, formed aluminum scraps, and the like. Examples of the acid include sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid, hydrochloric acid, and the like. Examples of the base include sodium hydroxide and potassium hydroxide. Among these, it is preferable to use an aqueous alkali solution such as sodium hydroxide. The dissolution amount of aluminum in the support surface, 0.5 to 5 g / m ² is preferred. After the immersion treatment with an alkaline aqueous solution, it is preferable to neutralize by immersion in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid or a mixed acid thereof.

  The electrochemical surface roughening method is not particularly limited, but a method of electrochemical surface roughening in an acidic electrolyte is preferable. As the acidic electrolytic solution, an acidic electrolytic solution usually used in an electrochemical surface roughening method can be used, but a hydrochloric acid-based or nitric acid-based electrolytic solution is preferably used. As the electrochemical surface roughening method, for example, methods described in JP-B-48-28123, British Patent No. 896,563 and JP-A-53-67507 can be used.

This roughening method can be generally performed by applying a voltage in the range of 1 to 50V, but is preferably selected from the range of 10 to 30V. Current density may be in the range of 10 to 200 A / dm ^2, preferably selected from the range of 50 to 150 A / dm ^2. The quantity of electricity may be in the range of 5000 C / dm ^2, preferably selected from the range of 100~2000C / dm ^2. The temperature at which the roughening method is performed can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C.

When electrochemical surface roughening is performed using a nitric acid-based electrolyte as the electrolyte, it can be generally performed by applying a voltage in the range of 1 to 50V, but is preferably selected from the range of 10 to 30V. . Current density may be in the range of 10 to 200 A / dm ^2, preferably selected from the range of 20 to 100 A / dm ^2. The quantity of electricity, may be in the range of 5000 C / dm ^2, preferably selected from the range of 100~2000C / dm ^2. The temperature at which the electrochemical surface roughening method is performed can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C. The concentration of nitric acid in the electrolytic solution is preferably 0.1 to 5% by mass. If necessary, nitrate, chloride, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, and the like can be added to the electrolytic solution.

In the case of using a hydrochloric acid-based electrolyte as the electrolyte, it can be generally performed by applying a voltage in the range of 1 to 50V, but is preferably selected from the range of 2 to 30V. Current density may be in the range of 10 to 200 A / dm ^2, preferably selected from the range of 50 to 150 A / dm ^2. The quantity of electricity may be in the range of ^{100~5,000C / dm 2, 100~2000C / dm} 2, and more preferably selected from the range of 200~1000C / dm ^2. The temperature at which the electrochemical surface roughening method is performed can be in the range of 10 to 50 ° C, but is preferably selected from the range of 15 to 45 ° C. The concentration of hydrochloric acid in the electrolytic solution is preferably 0.1 to 5% by mass.

After the surface is roughened by the electrochemical surface roughening method, it is preferably immersed in an acid or alkali aqueous solution in order to remove aluminum scraps on the surface. As the acid, sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid, nitric acid, hydrochloric acid and the like are used, and as the base, sodium hydroxide, potassium hydroxide and the like are used. Among these, it is preferable to use an alkaline aqueous solution. The dissolution amount of aluminum in the support surface, 0.5 to 5 g / m ² is preferred. In addition, it is preferable to carry out a neutralization treatment by immersing in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid or a mixed acid thereof after immersing with an alkaline aqueous solution.

  The mechanical surface roughening method and the electrochemical surface roughening method may each be used alone for roughing, or the mechanical surface roughening method followed by the electrochemical surface roughening method. You may roughen.

Following the roughening treatment, anodizing treatment is preferably performed. There is no restriction | limiting in particular in the method of the anodizing process which can be used in this invention, A well-known method can be used. By performing the anodizing treatment, an oxide film is formed on the substrate. For the anodizing treatment, a method of electrolyzing an aqueous solution containing sulfuric acid and / or phosphoric acid at a concentration of 10 to 50% as an electrolytic solution at a current density of 1 to 10 A / dm ² is preferably used. No. 1,412,768, a method of electrolysis at high current density in sulfuric acid, a method of electrolysis using phosphoric acid described in US Pat. No. 3,511,661, chromic acid, oxalic acid, malonic acid, etc. Examples thereof include a method using a solution containing one or more kinds. The formed anodic oxidation coating amount is suitably 1 to 50 mg / dm ² , preferably 10 to 40 mg / dm ² . The amount of anodic oxidation coating is, for example, by immersing an aluminum plate in a chromic phosphate solution (35% phosphoric acid solution 35 ml, prepared by dissolving 20 g of chromium oxide (IV) in 1 L of water), dissolving the oxide layer, and covering the plate It is obtained from mass change measurement before and after dissolution.

  The anodized base material may be subjected to a sealing treatment as necessary. The sealing treatment can be performed using a known method such as hot water treatment, boiling water treatment, water vapor treatment, sodium silicate treatment, dichromate aqueous solution treatment, nitrite treatment, ammonium acetate treatment.

  Further, after these treatments, as a hydrophilization treatment, a water-soluble resin such as polyvinyl phosphonic acid, a polymer or copolymer having a sulfonic acid group in the side chain, polyacrylic acid, a water-soluble metal salt (boric acid) Zinc or the like), or a primer coated with a yellow dye, amine salt or the like is also suitable. Further, a sol-gel treated substrate having a functional group capable of causing an addition reaction by a radical as disclosed in JP-A-5-304358 is also preferably used.

  Examples of the plastic film used as the substrate include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide, polyamide, polycarbonate (PC), polysulfone, polyphenylene oxide, and cellulose esters.

  Of these plastic films, polyester films such as PET and PEN are particularly preferably used as the substrate. Furthermore, it is preferable to use a support having a thermal dimensional change rate of 0.001 to 0.04% at 120 ° C. for 30 seconds obtained by the method described in JP-A-10-10676. A preferable polyester film is an unstretched polyester film, a uniaxially stretched polyester film, or a biaxially stretched polyester film. Of these, a longitudinally stretched polyester film uniaxially stretched in the film extrusion direction (longitudinal direction) is particularly preferable.

<Applying the undercoat layer to the substrate>
In the polyester film base material, easy adhesion treatment or undercoat layer coating can be performed in order to have various functions.

  Examples of the easy adhesion treatment include corona discharge treatment, flame treatment, plasma treatment, and ultraviolet irradiation treatment.

  As the undercoat layer, a layer containing gelatin or latex is preferably provided on the polyester film support. Among these, an antistatic undercoat layer described in paragraph numbers “0044” to “0116” of JP-A-7-191433 is preferably used. Further, the conductive polymer-containing layer described in paragraphs “0031” to “0073” of JP-A-7-20596 and the metal oxides described in paragraphs “0074” to “0081” of JP-A-7-20596 It is preferable to provide a conductive layer such as a layer. The conductive layer may be coated on any side as long as it is on the polyester film support, but it is preferably coated on the opposite side of the image forming functional layer with respect to the support. When this conductive layer is provided, the charging property is improved, the adhesion of dust and the like is reduced, and white spots failure during printing is greatly reduced.

<Hydrophilic layer>
When a plastic film as described above is used as the substrate, a hydrophilic layer is provided on the substrate to form a substrate having a hydrophilic surface. In this case, the hydrophilic layer preferably has a porous structure. In order to form a hydrophilic layer having a porous structure, the following materials for forming a hydrophilic matrix are preferably used. As a material for forming the hydrophilic matrix, a metal oxide is preferable.

(Metal oxide)
The metal oxide preferably contains fine metal oxide particles, and examples thereof include colloidal silica, alumina sol, titania sol, and other metal oxide sols. The form of the metal oxide fine particles may be spherical, needle-like, feather-like or any other form. The average particle diameter is preferably in the range of 3 to 100 nm, and several metal oxides having different average particle diameters. Fine particles can also be used in combination. Further, surface treatment may be performed on the particle surface.

  The metal oxide fine particles can be used as a binder by utilizing the film forming property. The decrease in hydrophilicity is less than when an organic binder is used, and it is suitable for use in a hydrophilic layer.

(Colloidal silica)
Among the metal oxides, colloidal silica can be particularly preferably used. Colloidal silica has the advantage of high film-forming properties even under relatively low temperature drying conditions, and can provide good strength. The colloidal silica preferably includes necklace-like colloidal silica, which will be described later, and fine particle colloidal silica having an average particle size of 20 nm or less, and the colloidal silica preferably exhibits alkalinity as a colloidal solution.

  Necklace-shaped colloidal silica is a generic term for an aqueous dispersion of spherical silica whose primary particle diameter is on the order of nm, and spherical colloidal silica whose primary particle diameter is 10 to 50 nm is bonded to a length of 50 to 400 nm. Means “pearl necklace-shaped” colloidal silica. The pearl necklace shape (that is, a pearl necklace shape) means that an image in a state where the silica particles of colloidal silica are connected and linked has a shape like a pearl necklace.

(Porous metal oxide particles)
In the present invention, porous metal oxide particles having a particle size of less than 1 μm can be contained as a porous material having a hydrophilic layer matrix structure. As the porous metal oxide particles, the following porous silica, porous aluminosilicate particles, or zeolite particles can be preferably used.

(Porous silica, porous silica, porous aluminosilicate particles)
The porous silica particles are generally produced by a wet method or a dry method. In the wet method, the gel obtained by neutralizing the aqueous silicate solution can be obtained by drying and pulverizing, or by pulverizing the precipitate deposited after neutralization. In the dry method, silicon tetrachloride is burned together with hydrogen and oxygen to obtain silica. These particles can be controlled in their porosity and particle size by adjusting the production conditions. As the porous silica particles, those obtained from a wet gel are particularly preferable.

  The porous aluminosilicate particles are produced, for example, by the method described in JP-A-10-71764. That is, amorphous composite particles synthesized by hydrolysis using aluminum alkoxide and silicon alkoxide as main components. The ratio of alumina to silica in the particles can be synthesized in the range of 1: 4 to 4: 1. Moreover, what was manufactured as composite particle | grains of 3 or more components by adding the alkoxide of another metal at the time of manufacture can also be used for this invention. These composite particles can also control the porosity and particle size by adjusting the production conditions.

  The porosity of the particles is preferably 0.5 ml / g or more in terms of pore volume, more preferably 0.8 ml / g or more, and further preferably 1.0 to 2.5 ml / g. preferable. The pore volume is closely related to the water retention of the coating film. The larger the pore volume, the better the water retention and the less difficult it is to stain during printing, and the water amount latitude is widened, but 0.5 to 2.5 ml / G prevents inadequate printing performance and lowers durability of the coating film.

(Measurement method of pore volume)
The above pore volume was measured by using Autosorb-1 (manufactured by Cantachrome) and relative to the assumption that the voids of the powder were filled with nitrogen by nitrogen adsorption measurement using a constant volume method. The pressure is calculated from the nitrogen adsorption amount at 0.998.

(Zeolite particles)
Zeolite is a crystalline aluminosilicate, which is a porous body having regular three-dimensional network voids having a pore diameter of 0.3 nm to 1 nm.

  Further, the hydrophilic layer matrix structure constituting the hydrophilic layer can contain layered clay mineral particles. Examples of the layered mineral particles include kaolinite, halloysite, talc, smectite (montmorillonite, beidellite, hectorite, sabonite, etc.), clay minerals such as vermiculite, mica (mica), chlorite, and hydrotalcite, layered polysilicate. (Kanemite, macatite, ialite, magadiaite, Kenyaite, etc.). In particular, the higher the charge density of the unit layer (unit layer), the higher the polarity and the higher the hydrophilicity. The charge density is preferably 0.25 or more, more preferably 0.6 or more. Examples of the layered mineral having such a charge density include smectite (charge density 0.25 to 0.6; negative charge), vermiculite (charge density 0.6 to 0.9; negative charge) and the like. In particular, synthetic fluorine mica is preferable because it can be obtained with a stable quality such as particle size. Further, among the synthetic fluorine mica, those that are swellable are preferable, and those that are free swell are more preferable.

  Also used are intercalation compounds of the above-mentioned layered minerals (pillar crystals, etc.), those subjected to ion exchange treatment, and those subjected to surface treatment (silane coupling treatment, compounding treatment with organic binder, etc.) can do.

  As the size of the flat lamellar mineral particles, the average particle diameter (maximum length of the particles) is less than 1 μm in the state of being contained in the layer (including the case where the swelling process and the dispersion peeling process have been performed). The aspect ratio is preferably 50 or more. If the particle size is less than 1 μm, the continuity and flexibility in the planar direction, which are the characteristics of the thin layered particles, are imparted to the coating film, and it is difficult to crack and it can be made a tough coating film in a dry state. Moreover, in the coating liquid containing many particulate matters, sedimentation of particulate matter can be suppressed by the thickening effect of the layered clay mineral. When the particle diameter is 1 μm or more, non-uniformity occurs in the coating film, and the strength may be locally reduced.

  On the other hand, when the aspect ratio is less than 50, the number of tabular grains with respect to the added amount is reduced, the viscosity is insufficient, and the effect of suppressing sedimentation of the particulate matter is reduced.

  The content of the layered mineral particles is preferably 0.1 to 30% by mass, and more preferably 1 to 10% by mass based on the entire layer. In particular, swellable synthetic fluorinated mica and smectite are preferable because they can be effective even when added in a small amount.

  The layered mineral particles may be added as a powder to the coating solution, but in order to obtain a good degree of dispersion even with a simple preparation method (no need for a dispersion step such as media dispersion), the layered mineral particles are used alone. It is preferable to prepare the gel swollen in water and add it to the coating solution.

In the hydrophilic layer matrix constituting the hydrophilic layer, a silicate aqueous solution can also be used as another additive material. Alkali metal silicates such as sodium silicate, potassium silicate, and lithium silicate are preferred, and the SiO ₂ / M ₂ O ratio is selected so that the pH of the entire coating solution when the silicate is added does not exceed 13. This is preferable for preventing dissolution of inorganic particles.

  Further, an inorganic polymer or organic-inorganic hybrid polymer by a so-called sol-gel method using a metal alkoxide can also be used. The formation of an inorganic polymer or an organic-inorganic hybrid polymer by the sol-gel method is described in, for example, “Application of the sol-gel method” (Sakuo Sakuo, published by Agne Jofusha) or in this book Known methods described in the cited documents can be used.

  In the present invention, a water-soluble resin may be contained. Examples of the water-soluble resin include conjugated dienes such as polysaccharides, polyethylene oxide, polypropylene oxide, polyvinyl alcohol (PVA), polyethylene glycol (PEG), polyvinyl ether, styrene-butadiene copolymer, and methyl methacrylate-butadiene copolymer. Resins such as polymer latex, acrylic polymer latex, vinyl polymer latex, polyacrylamide, and polyvinylpyrrolidone can be used, and the water-soluble resin used in the present invention is preferably a polysaccharide.

  As the polysaccharide, starch, cellulose, polyuronic acid, pullulan, and the like can be used, but cellulose derivatives such as methyl cellulose salt, carboxymethyl cellulose salt, hydroxyethyl cellulose salt are particularly preferable, and sodium salt and ammonium salt of carboxymethyl cellulose are preferable. More preferred. This is because an effect of forming the surface shape of the hydrophilic layer in a preferable state can be obtained by including the polysaccharide in the hydrophilic layer.

  The surface of the hydrophilic layer preferably has a concavo-convex structure with a pitch of 0.1 to 20 μm like the aluminum grain of the PS plate, and this concavo-convex improves water retention and image area retention. Such a concavo-convex structure can be formed by adding an appropriate amount of filler having an appropriate particle size to the hydrophilic layer matrix. However, the hydrophilic colloidal silica and the water-soluble polyvalent silica are added to the hydrophilic layer coating solution. It is preferable that a saccharide is contained and formed by causing phase separation when the hydrophilic layer is applied and dried so that a structure having better printability can be obtained.

  The shape of the concavo-convex structure (pitch, surface roughness, etc.) is determined depending on the type and addition amount of alkaline colloidal silica, the type and addition amount of water-soluble polysaccharides, the type and addition amount of other additives, the solid content concentration of the coating liquid, and the wetness. It is possible to appropriately control the film thickness, drying conditions, and the like.

  In the present invention, the water-soluble resin added to the hydrophilic matrix structure part is preferably present in a state where at least a part thereof is water-soluble and can be eluted in water. This is because even if it is a water-soluble material, when it is cross-linked by a cross-linking agent or the like and becomes insoluble in water, its hydrophilicity is lowered and printability may be deteriorated. Further, the resin may further contain a cationic resin. Examples of the cationic resin include polyalkylene polyamines such as polyethylene amine and polypropylene polyamine or derivatives thereof, and acrylic resins having a tertiary amino group or a quaternary ammonium group. , Diacrylamine and the like. The cationic resin may be added in the form of fine particles, and examples thereof include a cationic microgel described in JP-A-6-161101.

  In addition, the coating solution used for coating the hydrophilic layer can contain a water-soluble surfactant for the purpose of improving the coating property, and a silicon-based or fluorine-based surfactant is used. However, it is particularly preferable to use a surfactant containing silicon element because there is no fear of causing printing stains. The content of the surfactant is preferably 0.01 to 3% by mass, more preferably 0.03 to 1% by mass of the entire hydrophilic layer (solid content as the coating solution).

  The hydrophilic layer can contain a phosphate. In the present invention, since the hydrophilic layer coating solution is preferably alkaline, the phosphate is preferably added as trisodium phosphate or disodium hydrogen phosphate. By adding a phosphate, the effect of improving the mesh opening during printing can be obtained. The addition amount of the phosphate is preferably 0.1 to 5% by mass and more preferably 0.5 to 2% by mass as an effective amount excluding the hydrate.

  In the present invention, the reflection density on the surface of the support is particularly preferably in the range of 0.7 to 2.5 from the viewpoint of visible image properties. By making the surface of the substrate dark, the contrast with the whitened exposed portion is enhanced, and a good exposed visible image can be obtained. In order to set the reflection density of the substrate surface within the above range, the following method may be mentioned.

  In the case of an aluminum grain substrate, the reflection density can be adjusted to the above range by coloring the AD layer (adhesive layer) by a known electrolytic coloring method and appropriately adjusting the coloring conditions. In the case of a base material on which a hydrophilic layer is formed, a coloring pigment (preferably a black pigment) is contained in the hydrophilic layer, and the content ratio of the coloring pigment in the hydrophilic layer and the amount of the hydrophilic layer are appropriately adjusted. Thus, the reflection density can be within the above range.

  The reflection density in the present invention is a numerical value of density obtained by performing density measurement on an absolute white basis using a reflection densitometer D-196 manufactured by Gretag-Macbeth. When the substrate having a hydrophilic surface is light-transmitting, the measurement is performed on a white table (specifically, a table on which four sheets of coated paper used for printing are laid).

(printing)
The image-exposed printing plate material can be subjected to general lithographic printing using dampening water and printing ink. As a printing method, it is a preferable embodiment particularly when fountain solution that does not contain i-propanol as the fountain solution (that does not contain means a content of 0.5% by mass or less with respect to water) is used. .

  That is, in a preferred embodiment, the printing plate material of the present invention is subjected to image exposure with an infrared laser, developed with dampening water or dampening water and printing ink on a printing machine, and printed.

  The printing plate material after image formation is directly attached to the plate cylinder of the printing press, or the image forming is performed after the printing plate material is attached to the plate cylinder of the printing press, and the water supply roller and / or while rotating the plate cylinder By bringing the ink supply roller into contact with the printing plate material, it is possible to remove the non-image portion of the thermal image forming layer.

(On-press development method)
The removal of the non-image area, a so-called on-press development method will be described below.

  The removal of the non-image part (unexposed part) of the heat-sensitive image forming layer on the printing press can be carried out by contacting a watering roller or an ink roller while rotating the plate cylinder, as in the following examples: Alternatively, it can be performed by various other sequences.

  In this case, the water amount may be adjusted by increasing or decreasing the amount of dampening water required for printing. The water amount adjustment may be divided into multiple stages or steplessly. You may change it to.

  (1) As a sequence for starting printing, the plate cylinder is rotated 1 to several tens of times by contacting the watering roller, then the plate cylinder is rotated by contacting the ink roller one to several tens of times, and then printing is started. .

  (2) As a sequence for starting printing, contact the ink roller to rotate the plate cylinder 1 to several tens of times, then contact the watering roller to rotate the plate cylinder 1 to several tens of times, and then start printing .

  (3) As a sequence for starting printing, the watering roller and the ink roller are brought into contact with each other substantially simultaneously to rotate the plate cylinder 1 to several tens of times, and then printing is started.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, the embodiment of this invention is not limited to this. In Examples, “%” represents “% by mass” and “parts” represents “parts by mass” unless otherwise specified.

Example 1
<Preparation of substrate 1>
An aluminum plate (material 1050, tempered H16) having a thickness of 0.24 mm is immersed in a 1% sodium hydroxide aqueous solution at 50 ° C., dissolved so that the dissolution amount becomes 2 g / m ² , and washed with water. The sample was immersed in a 0.1% hydrochloric acid aqueous solution at 25 ° C. for 30 seconds, neutralized, and washed with water.

Next, this aluminum plate was subjected to an electrolytic surface roughening treatment with an electrolytic solution containing hydrochloric acid 10 g / L and aluminum 0.5 g / L using a sine wave alternating current and a peak current density of 50 A / dm ^2. went. The distance between the electrode and the sample surface at this time was 10 mm. Perform electrolytic graining treatment is divided into 12 times, and the quantity of electricity used in one treatment (at a positive polarity) as the 40C / dm ^2, treatment quantity of electricity 480C / dm ² in total (at a positive polarity). In addition, a rest period of 5 seconds was provided between each surface roughening treatment.

After electrolytic surface roughening, it is immersed in a 1% aqueous sodium hydroxide solution maintained at 50 ° C. and etched so that the dissolution amount including the smut of the roughened surface becomes 1.2 g / m ^2. And washed with water. Subsequently, it was immersed in a 10% aqueous sulfuric acid solution maintained at 25 ° C. for 10 seconds, neutralized, and then washed with water. Next, anodization was performed in a 20% sulfuric acid aqueous solution so that the amount of electricity was 150 C / dm ² under a constant voltage condition of 20 V, followed by washing with water.

  Next, after squeezing the surface water after washing with water, it was immersed in a 1% aqueous solution of sodium dihydrogen phosphate kept at 70 ° C. for 30 seconds, washed with water, and then dried at 80 ° C. for 5 minutes.

<Applying hydrophilic layer>
A material having the following composition was sufficiently stirred and mixed using a homogenizer, followed by filtration to prepare a hydrophilic layer 1 coating solution having a solid content of 15%.

On the roughened aluminum plate, the hydrophilic layer 1 coating solution was applied using a wire bar so that the applied amount after drying was 0.5 g / m ² and dried at 110 ° C. for 3 minutes. . Subsequently, the base material 1 which has a hydrophilic layer was produced by performing the aging process for 60 degreeC * 72 hours.
(Hydrophilic layer 1 coating solution)
Hydrophilic layer colloidal silica (alkaline): Snowtex-S (manufactured by Nissan Chemical Co., solid content 30%) 12.86 parts Necklace-shaped colloidal silica (alkaline): Snowtex-PSM (manufactured by Nissan Chemical Co., solid content) 20%) 35.83 parts Infrared absorbing dye: ADS830WS (manufactured by American Dye Source)
0.45 parts Layered mineral particles Montmorillonite: Mineral colloid MO (manufactured by Southern Clay Products, average particle size 0.1 μm) was vigorously stirred with a homogenizer to form a 5% water-swelling gel 6.00 parts Sodium carboxymethyl cellulose: 4% aqueous solution of CMC1220 (manufactured by Daicel Chemical Industries) 3.75 parts 10% aqueous solution of trisodium phosphate 12 water (reagent manufactured by Kanto Chemical Co., Ltd.) 0.75 parts Porous metal oxide particles SILTON AMT08L (manufactured by Mizusawa Chemical Co., Ltd., Porous aluminosilicate particles, average particle size 0.6 μm) 1.50 parts Porous metal oxide particles Silton JC-30 (manufactured by Mizusawa Chemical Co., Ltd., porous aluminosilicate particles, average particle size 3 μm) 1.50 parts pure water 37.36 parts <Preparation of printing plate material>
A 0.1% calcium sulfate aqueous solution was adjusted to 25 ° C., applied onto the substrate 1 so that the amount applied after drying was 0.05 g / m ^2, and dried at 60 ° C. for 3 minutes. Subsequently, an image forming layer material having the following composition was sufficiently mixed and stirred, and filtered to prepare a coating solution for the image forming layer a having a solid content of 10%.

On the substrate 1 on which the above-mentioned water-soluble compound coating solution has been applied and dried, the image forming layer a coating solution is applied using a wire bar so that the dry weight is 0.7 g / m ² . Dry at 1 ° C. for 1 minute. Next, an aging treatment at 40 ° C. for 24 hours was performed to obtain a printing plate material 1.
(Image forming layer a coating solution)
Polystyrene-block-poly (methyl methacrylate) aqueous dispersion (average particle size 0.3 μm, softening point 65 ° C., solid content 40%) 17 parts disaccharide trehalose (trade name Treha, melting point 97 ° C., Hayashibara Shoji Co., Ltd.) , Solid content 20% 12 parts Sodium polyacrylate (Aquaric DL522: manufactured by Nippon Shokubai Co., Ltd.), solid content 10% 6 parts Photothermal conversion dye (ADS830WS: manufactured by American Dye Source) 1% aqueous solution 55 parts Pure water 10 parts <Image formation by infrared laser exposure>
First exposure: A far-infrared radiation hollow ceramic heater is installed adjacent to the laser unit of an outer cylindrical scanning drum setter, and the laser is irradiated when the laser unit and the ceramic heater are moved by sub-scanning. The output of the ceramic heater was adjusted so that the plate temperature at the position was 200 ° C.

The printing plate material was wound around the exposure drum and fixed. The first exposure is the far infrared heater, and the second exposure is a laser beam having a wavelength of 830 nm and a spot diameter of about 18 μm, an exposure energy of 150 mJ / cm ² and an exposure energy of 2,400 dpi (dpi is 1 inch = 2.54 cm). An image was formed with 175 lines. The interval between the first exposure and the second exposure is 0.5 seconds.

  The obtained printing plate is referred to as Example 1.

Example 2
In Example 1, the exposure was performed in the same manner as in Example 1 except that the first exposure was imagewise exposed with a laser beam, and the second exposure was performed with a far-infrared heater.

Comparative Example 1
In Example 1, exposure was performed without using a ceramic heater.

Comparative Example 2
In Example 1, exposure was performed in the same manner as in Example 1 except that the setting position of the ceramic heater was changed and the interval between the first exposure and the second exposure was changed to 6 seconds.

Comparative Example 3
In Example 1, exposure was performed in the same manner as in Example 1 except that the output of the ceramic heater was adjusted and the temperature of the plate surface was 115 ° C.

<Evaluation>
Evaluation was performed as follows.

<Exposure Visibility>
A 50% halftone dot image portion of each exposed printing plate material was observed at a magnification of 200 times using a microscope VH-X (manufactured by Keyence Corporation). The discriminability between the image portion and the non-image portion was visually evaluated by the following index.

◎: Very good ○: Good △: Can be identified ×: Difficult to identify << On-machine developability >>
(Printing method)
The exposed printing plate material sample is attached to a Heidel GTO printing machine without developing, and 45 times water diluted solution of SEU-3 (manufactured by Konica) is used as an etching solution, and HiEcho (Toyo Ink Co., Ltd.) is used as an ink. And printing was performed using high-quality paper as printing paper. Printing was performed in an environment of 23 ° C. and 48% RH (relative humidity).

  For each printing plate material, the number of sheets printed from the printing was determined to obtain a printed matter with good image quality. The on-machine development end index is that the non-image area is not smudged on the printed matter, the density of the solid image area is 1.5 or more (measured in the M mode using Macbeth RD918), and 90% of the mesh The point image is open.

<Press life>
Printing was performed in the same manner as described above, and the printed matter was confirmed every 5,000 sheets, and the number of sheets at which 3% halftone dots started to be missing was counted as the number of printing durability.

  The results are also shown in Table 1.

  It can be seen from Table 1 that the lithographic printing plate produced by the method for producing a lithographic printing plate material of the present invention is excellent in exposure visible image quality, and excellent in on-press developability and printing durability.

Claims (10)

A lithographic printing plate comprising a plurality of steps of exposing a lithographic printing plate material having a support and a heat-sensitive recording layer containing heat-fused fine particles or heat-sensitive hydrophobic polymer particles provided on the support. Production method. The method for producing a lithographic printing plate according to claim 1, wherein at least one of the steps of exposing the lithographic printing plate material heats the surface of the lithographic printing plate material to 120 ° C or more during infrared exposure. 3. The method according to claim 1, wherein the plurality of exposure steps include a first step of exposing the entire surface of the lithographic printing plate material with infrared rays, and a second step of imagewise exposure with infrared laser light thereafter. The manufacturing method of the lithographic printing plate of description. 3. The method according to claim 1, wherein the plurality of exposure steps include a first step of imagewise exposure with infrared laser light and a second step of exposing the entire surface of the lithographic printing plate material with infrared rays thereafter. The manufacturing method of the lithographic printing plate of description. An exposure method for a lithographic printing plate material, wherein the first exposure is performed by infrared irradiation, and the second exposure is an imagewise exposure using infrared laser light. An exposure method for a lithographic printing plate material, wherein the first exposure is imagewise exposure using infrared laser light, and the second exposure is exposure by infrared irradiation. An exposure method for a lithographic printing plate material, wherein the first exposure and the second exposure are performed by imagewise exposure using infrared laser light. The lithographic printing plate material exposure method according to any one of claims 5 to 7, wherein an interval between the first exposure and the second exposure is 0.01 to 5 seconds. The plurality of steps of exposing a lithographic printing plate material having a support and a heat-sensitive recording layer containing heat-bonding fine particles or heat-sensitive hydrophobic polymer particles provided on the support, according to any one of claims 5 to 8. An exposure method for a lithographic printing plate material comprising the exposure method described in 1. A printing method comprising printing after development on a printing press using the planographic printing plate obtained by the method for producing a planographic printing plate according to any one of claims 1 to 4.