JP2005111822A - Printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing method being excellent in on-machine developability and printing stability and enabling attainment of printed matter excellent in a finished quality. <P>SOLUTION: In the printing method wherein a lithographic plate material is subjected to image exposure by a laser light and then development and printing are performed, the lithographic plate material has a thermal image formation layer on an aluminum support having a surface roughened electrolytically in an electrolyte containing a hydrochloric acid. The development is conducted on printing equipment by using dampening water, or the dampening water and printing ink, while the printing ink used for the printing contains soybean oil of 5-50 mass %. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a printing method using a lithographic printing plate material having an image forming layer provided on an aluminum support, which can be developed on a printing press. More specifically, a printing method in which image exposure is performed by a computer-to-plate (hereinafter abbreviated as CTP) method, followed by development using dampening water or dampening water and ink on a printing apparatus, and printing. About.

  Along with the digitization of print data, there is a need for a CTP method that is inexpensive and easy to handle and has the same printability as printing using a conventional PS plate. In recent years, various CTP methods using infrared laser recording have been proposed.

  One of these CTP methods is a method of forming an image by liquid development by changing the solubility of an image forming layer of a printing plate material in a developing solution by exposure, generally called a wet type CTP method. Can be mentioned. However, this method requires a special alkaline developer for development as in the case of the conventional PS plate, and developability changes depending on the state of the developer (temperature, fatigue), and stable image reproducibility can be obtained. There are various problems, such as lack of handling and limitations in handling in a bright room.

  On the other hand, development of a so-called dry CTP (including development on a printing press) system that does not require a special wet development process is also in progress. The dry CTP method is attracting a great deal of attention because it can be applied to a direct imaging (DI) type printing apparatus in which an image is directly recorded on a printing apparatus and printing is performed as it is.

  Examples of those used in the dry CTP method include those described in JP-A-8-507727, JP-A-6-186750, JP-A-6-199064, JP-A-7-314934, JP-A-10-58636, and JP-A-10-244773. Examples include an ablation type CTP method, a method in which a heat-sensitive image forming layer is provided on a substrate, and an image portion is formed on a hydrophilic layer by image-like heat generation by laser exposure (for example, Patent Document 1, Patent) Reference 2 and Patent Reference 3).

  A printing plate material having a heat-sensitive image forming layer that converts laser light into heat and forms an image portion on a hydrophilic layer has a sharp dot shape and is suitable for high-definition image formation.

  However, in the printing plate material having the thermal image forming layer, the developing speed by the fountain solution on the printing machine is insufficient, and the number of so-called damaged papers is large. There are problems such as the occurrence of spots and spot-like stains, and the printing stability and the finished quality of printed matter are insufficient.

On the other hand, in recent printing, printing ink that does not use VOC (Volatile Organic Compound) contained in conventional printing ink has been developed from an environmental point of view, and soybean oil is used as one of them. Ink is known for use in printing on lithographic printing plates that use wet development using a grained aluminum plate, and special fountain solution in silver halide printing plates that use silver halide. It is known to use for printing in use (see, for example, Patent Document 4).
JP 2001-96710 A Japanese Patent Laid-Open No. 2001-138852 JP 2001-113848 A JP 2002-283766 A

  An object of the present invention is to provide a printing method capable of obtaining a printed matter having excellent on-press developability and printing stability and excellent finished quality.

The object of the present invention is achieved by the following constitution.
(Claim 1)
In a printing method in which a lithographic printing plate material is subjected to image exposure with a laser beam and then developed and printed, a thermal image is formed on an aluminum support whose surface is electrolytically roughened in an electrolytic solution containing hydrochloric acid. A lithographic printing plate material having a layer, wherein the development is performed on a printing apparatus using dampening water or dampening water and printing ink, and the printing ink used for the printing contains soybean oil in an amount of 5% by mass to 50% by mass. A printing method comprising a printing ink containing mass%.
(Claim 2)
The printing method according to claim 1, wherein the fountain solution does not contain isopropanol.
(Claim 3)
The printing method according to claim 1, wherein the fountain solution is an aqueous solution containing a surfactant.
(Claim 4)
4. The printing method according to claim 1, wherein the center line average roughness (Ra) of the surface of the aluminum support on the heat-sensitive image forming layer side is 0.20 to 0.4 μm.

  According to the present invention, it is possible to provide a printing method capable of obtaining a printed matter having a high development speed on a printing press and having good dot reproducibility without causing spot-like stains during printing.

  The present invention relates to a printing method capable of on-press development using a lithographic printing plate material having an aluminum support, having a high on-press development speed, and capable of reproducing a high-definition image without causing spot-like stains. It is.

  The present invention is a printing method in which an on-press developable photosensitive printing plate material having a thermal image-forming layer on a specific aluminum support and an ink containing a specific amount of soybean oil are used in combination.

(Printing ink)
The ink containing soybean oil according to the present invention is usually a mixture of an organic / inorganic pigment, a binder resin, soybean oil, a high-boiling petroleum solvent, and additionally, a plasticizer, a stabilizer, a drying agent, Thickeners, dispersants, fillers and the like may be included.

  The effect of the present invention is exerted on ink containing a certain amount or more of soybean oil, and ink certified by the American Soybean Association (ASA) by providing a soy seal certification system can be used.

  A known soybean oil can be used as the soybean oil of the present invention. Edible soybean oil (refined soybean oil) certified by the Japanese Agricultural Standard is particularly preferably used.

  The printing ink used for this invention contains soybean oil in 5-50 mass% with respect to printing ink. The preferred amount of soybean oil to be added varies depending on the type of ink, but is 20 to 50% by mass for sheet-fed ink and foam ink, 7 to 20% by mass for off-ring heat set ink, and 40 to 50 mass for black ink for newspaper ink. %, 30 to 40% by mass for color ink, and 20 to 30% by mass for business foam ink.

  As organic / inorganic pigments, disazo yellow, brilliant carmine 6B, phthalocyanine blue, lake red C, carbon black, titanium oxide, calcium carbonate and the like can be used.

  As binder resin, natural or processed resin such as rosin, copal, dammar, shellac, cured rosin, rosin ester, phenol resin, rosin modified phenol resin, 100% phenol resin, maleic acid resin, alkyd resin, petroleum resin, vinyl resin Acrylic resin, polyamide resin, epoxy resin, amino alkyd resin, polyurethane resin, amino blast resin and the like are preferable.

  Examples of the high-boiling petroleum solvent include a commercially available petroleum hydrocarbon solvent, a normal paraffin or isoparaffin single composition, a paraffin and naphthene compound, a paraffin, naphthene, and an aroma compound. Examples of commercially available products include “Isolan S”, “Isolan R”, “No. 5 Solvent”, “No. 6 Solvent”, “No. 7 Solvent”, “AF Solvent 5”, “AF Solvent 6”, “AF Solvent 7” manufactured by Nippon Petrochemical Co., Ltd. Or the like.

  The ink containing soybean oil according to the present invention is sold by each ink manufacturer and can be easily obtained.

  For example, Naturalis 100 (Naturalith) sheet-fed ink, Web World Advan off-wheel ink, <above, Dainippon Ink & Chemicals, Inc.>, TK High Unity SOY sheet ink, TK High Echo SOY sheet-fed ink, CK Win Echo SOY sheet ink, WD Super Leo Echo SOY off-wheel ink, WD Leo Echo SOY off-wheel ink, SCRSOY business form inki <more, Toyo Ink Co., Ltd. > Etc.

(Support and surface treatment)
The support of the lithographic printing plate used in the present invention uses an aluminum plate that has been subjected to a surface roughening treatment in an electrolyte containing hydrochloric acid.

  The aluminum plate may be a pure aluminum plate or an aluminum alloy plate.

  Various aluminum alloys can be used, for example, alloys of aluminum and metals such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel, titanium, sodium, iron, etc. An aluminum plate produced by the method can be used. In addition, a recycled aluminum plate obtained by rolling recycled aluminum ingots such as scrap materials and recycled materials that are becoming popular in recent years can also be used.

  The support of the lithographic printing plate used in the present invention is preferably subjected to a degreasing treatment in order to remove the rolling oil on the surface prior to roughening (graining treatment). 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 caustic soda can be used for the degreasing treatment. When an alkaline aqueous solution such as caustic soda 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 caustic soda is used for the degreasing treatment, smut is generated on the surface of the support. In this case, the substrate is immersed in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid, or a mixed acid thereof and desmutted. It is preferable to perform the treatment.

  Next, a roughening process is performed. In the present invention, AC electrolytic surface roughening treatment is performed in an electrolytic solution containing hydrochloric acid, but prior to that, mechanical surface roughening treatment and preliminary electrolytic surface roughening treatment mainly composed of nitric acid may be performed.

The mechanical roughening method is not particularly limited, but a brush polishing method and a honing polishing method are preferable. The roughening by the brush polishing method is, for example, by rotating a rotating brush using a bristle having a diameter of 0.2 to 0.8 mm, and for example, volcanic ash particles having a particle size 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 size of 10 to 100 μm in water, injecting pressure from a nozzle, and causing the surface to collide obliquely with the support surface. Can do. Further, for example, abrasive particles having a particle size of 10 to 100 μm are applied to the support surface so as to be present 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 a pressure to transfer the rough surface pattern of the sheet.

After the surface is roughened by the mechanical surface 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 support, 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 carry out a neutralization treatment by immersion in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid or a mixed acid thereof.

The preliminary electrolytic surface roughening treatment mainly composed of nitric acid can be generally performed by applying a voltage in the range of 1 to 50 volts, but is preferably selected from the range of 10 to 30 volts. 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 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, nitrates, chlorides, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, aluminum ions, and the like can be added to the electrolytic solution.

After the electrolytic surface-roughening treatment mainly composed of nitric acid, it is preferably immersed in an acid or alkali aqueous solution in order to remove aluminum scraps on the surface. 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 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 that after the immersion treatment with an alkaline aqueous solution, neutralization treatment is performed by immersion in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid or a mixed acid thereof.

  Next, in the present invention, an AC electrolytic surface roughening treatment is performed in an electrolytic solution containing hydrochloric acid.

  The hydrochloric acid concentration is preferably 5 to 20 g / l, more preferably 6 to 15 g / l.

The current density is 15 to 60 A / dm ² , preferably 20 to 50 A / dm ² . The quantity of electricity was 400~1500C / dm ^2, preferably 500~1000C / dm ^2. The frequency is preferably in the range of 40 to 150 Hz.

  The temperature of the electrolytic solution is preferably in the range of 15 to 50 ° C, particularly preferably in the range of 20 to 40 ° C.

  The treatment time is preferably 5 to 80 seconds, particularly preferably 10 to 60 seconds.

  If necessary, nitrates, chlorides, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid, aluminum ions, and the like can be added to the electrolytic solution.

  The amount to be added is preferably 20% by mass or less, particularly preferably 10% by mass or less based on hydrochloric acid.

  After the electrolytic surface-roughening treatment is performed in the electrolytic solution containing hydrochloric acid, it is preferably immersed in an aqueous solution of acid or alkali in order to remove aluminum scraps on the surface.

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 alkaline aqueous solution. The amount of aluminum dissolved on the surface is preferably 0.5 to ² g / m2. In addition, it is preferable that after the immersion treatment with an alkaline aqueous solution, neutralization treatment is performed by immersion in an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid or a mixed acid thereof.

Following the roughening treatment, an anodizing treatment is performed to form an anodized film. The anodizing method used in the present invention is performed using sulfuric acid or an electrolytic solution mainly composed of sulfuric acid as the electrolytic solution. The concentration of sulfuric acid is preferably 5 to 50% by mass, particularly preferably 10 to 35% by mass. The temperature is preferably 10 to 50 ° C. The treatment voltage is preferably 18V or more, and more preferably 20V or more. Current density is preferably 1~30A / dm ^2. Quantity of electricity is preferably from 200~600C / dm ^2.

The anodic oxidation coating amount to be formed is adjusted to ³ to 5 g / m ^2, and preferably 4 to 5 g / m ² . The amount of anodic oxidation coating is, for example, by immersing an aluminum plate in a chromic phosphate solution (85% phosphoric acid solution: 35 ml, prepared by dissolving 20 g of chromium (IV) oxide in 1 L of water) to dissolve the oxide layer, It is obtained from mass change measurement before and after dissolution of the coating on the plate. Micropores are generated in the anodized film, and the density of the micropores is preferably 400 to 700 / μm ^{2, and} more preferably 400 to 600 / μm ² .

  The anodized support may be sealed as necessary. These sealing treatments can be performed using known methods such as hot water treatment, boiling water treatment, water vapor treatment, sodium silicate treatment, dichromate aqueous solution treatment, nitrite treatment, and ammonium acetate treatment.

  Furthermore, in the present invention, it is preferable to perform a hydrophilic treatment after performing these treatments. Hydrophilization treatment is not particularly limited, but a water-soluble resin such as polyvinylphosphonic acid, a polymer and copolymer having a sulfonic acid group in the side chain, polyacrylic acid, a water-soluble metal salt (for example, zinc borate) or Undercoat with yellow dye or amine salt can be used.

  Furthermore, a sol-gel treated substrate in which a functional group capable of causing an addition reaction by a radical as disclosed in JP-A-5-304358 is covalently used. Preferably, the support surface is hydrophilized with polyvinylphosphonic acid. The treatment is not limited to a coating method, a spray method, a dip method, or the like, but a dip method is suitable for making the equipment inexpensive. In the case of a dip type, it is preferable to treat polyvinylphosphonic acid with a 0.05 to 3% aqueous solution.

  The treatment temperature is preferably 20 to 90 ° C., and the treatment time is preferably 10 to 180 seconds. After the treatment, it is preferable to perform a squeegee treatment or a water washing treatment in order to remove the excessively laminated polyvinylphosphonic acid. Furthermore, it is preferable to perform a drying process. As a drying temperature, 20-95 degreeC is preferable.

  The centerline average roughness (Ra) of the surface of the aluminum support thus obtained on the image forming layer side is preferably 0.2 to 0.4 μm, and more preferably 0.25 to 0.35 μm. Roughness can be controlled by a combination of hydrochloric acid concentration, current density, and quantity of electricity.

  The center line average roughness is a center line average roughness (Ra) in three-dimensional roughness measurement, and is defined by JIS-B-0601 of JIS surface roughness.

That is, the centerline average roughness (Ra) by analog measurement is obtained by extracting a portion of the measurement length L from the roughness curve in the direction of the centerline and setting the cut-off value as 0.8 mm to X. When the axis and the direction of the vertical magnification are represented by the Y axis and the roughness curve is represented by Y = f (X), the value obtained by the following formula is represented by micrometers (μm).

  In addition, the centerline average roughness (Ra) by digital measurement is a specific sampling length, and the height of M points in the X direction, N points in the Y direction, and a total of MN points are measured to obtain a roughness curved surface. The difference between each measurement point with respect to the average height of the roughness curved surface is Z, and the value obtained according to the following formula is expressed in micrometers (μm).

  As a measuring apparatus that can be used as a measuring method of the center line average roughness (Ra), for example, an RSTPLUS non-contact three-dimensional micro surface shape measuring system manufactured by WYKO can be exemplified.

(Thermal image forming layer)
A heat-sensitive image forming layer is a layer that can form an image by heating, and a layer containing a heat-meltable material or a heat-fusible material, or changes from hydrophilic to hydrophobic or from hydrophobic to hydrophilic by heating. Is a layer.

  The heat-sensitive image forming layer is heated imagewise by image exposure with laser light.

  In the present invention, a lithographic printing plate material having a layer containing a photothermal conversion material, which will be described later, is preferably used, and particularly when the lithographic printing plate material containing a photothermal conversion material in the image forming layer or its adjacent layer is used. Is big.

  Examples of the material used for the layer that changes from hydrophilic to hydrophobic or from hydrophobic to hydrophilic by the heating described above include, for example, polymers containing aryl diazosulfonate units disclosed in JP-A-2000-56449. Examples include hydrophobizing precursors that change from hydrophilicity (water-soluble or water-swellable) to hydrophobicity by heat, or polarity-converting polymer compounds that change the polarity by laser exposure and lead the layer to hydrophilicity. It is done.

  The heat-meltable material or heat-fusible material used in the heat-sensitive image forming layer is preferably contained in the form of fine particles, and examples thereof include the following heat-meltable fine particles and heat-fusible fine particles. .

  The heat-meltable fine particles are fine 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 ° C. or higher and 120 ° C. or lower, a melting point of 60 ° C. or higher and 150 ° C. or lower, more preferably a softening point of 40 ° C. or higher and 100 ° C. or lower, and a melting point of 60 ° C. or higher and 120 ° C. or lower. When the melting point is less than 60 ° C., storage stability is a problem, and when the melting point is higher than 300 ° C., ink deposition sensitivity is lowered.

  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, ester groups, carboxyl groups, aldehyde groups, and peroxide groups.

  Furthermore, in order to lower the softening point and improve the workability, these waxes are stearamide, linolenamide, laurylamide, myristamide, hardened beef fatty acid amide, palmitoamide, oleic acid amide, rice sugar fatty acid amide, coconut fatty acid amide. Alternatively, methylolated products of these fatty acid amides, methylene bisstellaramide, ethylene bisstellaramide, and the like can be added. 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. In addition, 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 or the like is improved.

  The heat-meltable fine particles are preferably dispersible in water, and the average particle size is preferably 0.01 to 10 μm, more preferably 0.1 to 3 μm. When the average particle size is smaller than 0.01 μm, when the coating liquid for the layer containing the heat-meltable fine particles is applied onto the porous hydrophilic layer described later, the heat-meltable fine particles are not removed from the pores of the hydrophilic layer. It becomes easy to enter inside or into the gaps between fine irregularities on the surface of the hydrophilic layer, and the on-press development becomes insufficient, which may cause scumming. When the average particle size of the heat-meltable fine particles is larger than 10 μm, the resolution is lowered.

  Further, the composition of the heat-meltable 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 formation method, a sol-gel method, or the like can be used.
As content of the heat-meltable microparticles | fine-particles in a layer, 1-90 mass% of the whole layer is preferable, and 5-80 mass% is more preferable.

  Examples of the heat-fusible fine particles include thermoplastic hydrophobic polymer fine particles, and there is no specific upper limit for the softening temperature of the polymer fine particles, but the temperature is lower than the decomposition temperature of the polymer fine particles. Is preferred. 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, for example, diene (co) polymers such as polypropylene, polybutadiene, polyisoprene and ethylene-butadiene copolymer, styrene-butadiene copolymer, Synthetic rubbers such as methyl methacrylate-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 etc. of polymers Ester (co) polymer, 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 polymer fine 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 off to form fine particles. In any of the methods, a surfactant, such as sodium lauryl sulfate, sodium dodecylbenzenesulfonate, polyethylene glycol, or a water-soluble resin, such as polyvinyl alcohol, is used as a dispersant or stabilizer in polymerization or micronization as necessary. May be used.

  The heat-fusible fine particles are preferably dispersible in water, and the average particle size is preferably 0.01 to 10 μm, more preferably 0.1 to 3 μm. When the average particle size is smaller than 0.01 μm, when the coating liquid for the layer containing the heat-fusible fine particles is applied onto the porous hydrophilic layer described later, the heat-fusible fine particles It becomes easy to get into the pores or into the gaps between the fine irregularities on the surface of the hydrophilic layer, and the on-press development becomes insufficient, resulting in fear of soiling. When the average particle size of the heat-fusible fine particles is larger than 10 μm, the resolution is lowered.

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

As a coating method, a known microcapsule formation method, a sol-gel method, or the like can be used.
As content of the thermoplastic fine particle in a layer, 1-90 mass% of the whole layer is preferable, and 5-80 mass% is more preferable.

  Examples of the microcapsules include microcapsules enclosing a hydrophobic material described in JP-A No. 2002-2135 and JP-A No. 2002-19317.

  The microcapsules preferably have an average diameter of 0.1 to 10 μm, more preferably 0.3 to 5 μm, and even 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 microcapsule 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, known materials and methods described in “New Microcapsules, Production Methods, Properties, and Applications” (Takeshi Kondo, Masumi Koishi / Sankyo Publishing Co., Ltd.) or cited references are used. be able to.

  The film thickness of the heat-sensitive image forming layer is preferably from 0.1 μm to 10 μm, particularly preferably from 1 to 5 μm.

(Photothermal conversion material)
Examples of the photothermal conversion material used in the image forming layer of the present invention include the following dyes and pigments.

  Examples of the dye include organic compounds such as cyanine dyes, croconium dyes, polymethine dyes, azurenium dyes, squalium dyes, thiopyrylium dyes, naphthoquinone dyes, anthraquinone dyes, which are general infrared absorbing dyes, phthalocyanines , Naphthalocyanine-based, azo-based, thioamide-based, dithiol-based, and indoaniline-based organometallic complexes. 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, Kaihei 3-26593, JP-A-3-30991, JP-A-3-34891, JP-A-3-36093, JP-A-3-36094, JP-A-3-36095, JP-A-3-42281, JP-A-3-42281 Examples thereof include compounds described in JP-A-3-97589, JP-A-3-103476, and the like. These can be used alone or in combination of two or more.

  JP-A-11-240270, JP-A-11-265062, JP-A-2000-309174, JP-A-2002-49147, JP-A-2001-162965, JP-A-2002-144750, JP-A-2001-219667. The compounds described in (1) can also be preferably used.

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

  As carbon, furnace black or acetylene black is particularly preferable. 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.

  Examples of the former include black iron oxide and black composite metal oxides containing two or more metals.

Examples of the latter include SnO ₂ doped with Sb (ATO), In ₂ O ₃ doped with Sn (ITO), TiO ₂ , TiO ₂ with reduced TiO ₂ (titanium oxynitride, generally titanium black), etc. Is mentioned. Further, it can also be used those obtained by coating the core material _{(BaSO 4, TiO 2, 9Al} 2 O 3 · 2B 2 O, K 2 O · nTiO 2 , etc.) in these metal oxides. These particle sizes are 0.5 μm or less, preferably 100 nm or less, and more preferably 50 nm or less.

  Among these photothermal conversion materials, black iron oxide and black composite metal oxides containing two or more metals are more preferable materials.

The black iron oxide (Fe ₃ O ₄ ) is preferably particles having an average particle diameter of 0.01 to 1 μm and an acicular ratio (major axis diameter / minor axis diameter) of 1 to 1.5. It is preferably substantially spherical (acicular ratio 1) or has an octahedral shape (acicular ratio about 1.4).

  Examples of such black iron oxide particles include TAROX series manufactured by Titanium Industry Co., Ltd. As the spherical particles, BL-100 (particle diameter 0.2 to 0.6 μm), BL-500 (particle diameter 0.3 to 1.0 μm), or the like can be preferably used. Further, as octahedral shaped particles, ABL-203 (particle size 0.4 to 0.5 μm), ABL-204 (particle size 0.3 to 0.4 μm), ABL-205 (particle size 0.2 to 0) .3 μm), ABL-207 (particle size: 0.2 μm) and the like can be preferably used.

Furthermore, particles whose surface is coated with an inorganic substance such as SiO ₂ can also be preferably used. As such particles, spherical particles coated with SiO ₂ : BL-200 (particle size 0.2 to 0) .3 μm), octahedral shaped particles: ABL-207A (particle size 0.2 μm).

  Specifically, the black composite metal oxide is a composite metal oxide composed of two or more metals selected from Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sb, and Ba. . These are disclosed by methods disclosed in JP-A-8-27393, JP-A-9-25126, JP-A-9-237570, JP-A-9-241529, JP-A-10-231441, and the like. Can be manufactured.

  The composite metal oxide used in the present invention is particularly preferably a Cu-Cr-Mn-based or Cu-Fe-Mn-based composite metal oxide. In the case of a Cu—Cr—Mn system, it is preferable to perform the treatment disclosed in JP-A-8-27393 in order to reduce the elution of hexavalent chromium. These composite metal oxides are colored with respect to the amount added, that is, they have good photothermal conversion efficiency.

  These composite metal oxides preferably have an average primary particle size of 1 μm or less, and more preferably have an average primary particle size in the range of 0.01 to 0.5 μm. When the average primary particle diameter is 1 μm or less, the photothermal conversion ability with respect to the addition amount becomes better, and when the average primary particle diameter is within the range of 0.01 to 0.5 μm, the photothermal conversion ability with respect to the addition amount is obtained. Better.

  However, the photothermal conversion ability with respect to the addition amount is greatly affected by the degree of dispersion of the particles, and the better the dispersion, the better. Therefore, it is preferable to disperse these composite metal oxide particles by a known method separately before adding them to the layer coating solution to prepare a dispersion (paste).

Since dispersion becomes difficult when the average primary particle size is less than 0.01, a dispersing agent can be appropriately used for dispersion. The addition amount of the dispersant is preferably 0.01 to 5% by mass, and more preferably 0.1 to 2% by mass with respect to the composite metal oxide particles.
(Other materials that can be included in the image forming layer)
The image forming layer used in the present invention may further contain the following materials.

  The above-mentioned photothermal conversion material can be contained in the image forming layer. The image forming layer is preferably made of a material that is less colored with visible light.

  The image forming layer can contain a water-soluble resin or a water-dispersible resin. Examples of water-soluble resins and water-dispersible resins include oligosaccharides, polysaccharides, polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyethylene glycol (PEG), polyvinyl ether, styrene-butadiene copolymers, and methyl methacrylate-butadiene copolymers. Examples thereof include resins such as conjugated diene polymer latex, acrylic polymer latex, vinyl polymer latex, polyacrylic acid, polyacrylate, polyacrylamide, and polyvinylpyrrolidone.

Of these, oligosaccharides, polysaccharides, polyacrylic acid, polyacrylates (such as Na salts), and polyacrylamide are preferable.
Examples of the oligosaccharide include raffinose, trehalose, maltose, galactose, sucrose, and lactose, and trehalose is particularly preferable.
As polysaccharides, starches, celluloses, polyuronic acids, pullulans and the like can be used, but cellulose derivatives such as methyl cellulose salts, carboxymethyl cellulose salts, hydroxyethyl cellulose salts are particularly preferable, and sodium salts and ammonium salts of carboxymethyl cellulose are preferable. More preferred.

  The polyacrylic acid, polyacrylic acid, polyacrylate (Na salt, etc.), and polyacrylamide preferably have a molecular weight of 3,000 to 5,000,000, and more preferably 5,000 to 1,000,000.

  The image forming layer can contain a water-soluble surfactant. A surfactant such as Si-based or F-based can be used, but it is particularly preferable to use a surfactant containing Si 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, based on the entire hydrophilic layer (solid content as the coating solution).

Further, it may contain an acid (phosphoric acid, acetic acid, etc.) or an alkali (sodium hydroxide, silicate, phosphate, etc.) for pH adjustment.
The amount per image forming layer, a 0.01 to 10 g / m ^2, preferably from 0.1 to 3 g / m ^2, more preferably from 0.2 to 2 g / m ^2.
(Protective layer)
A protective layer can also be provided on the image forming layer.

  As a material used for the protective layer, the above-mentioned water-soluble resin and water-dispersible resin can be preferably used.

Further, hydrophilic overcoat layers described in JP-A Nos. 2002-19318 and 2002-86948 can also be preferably used.
The amount per the protective layer is 0.01 to 10 g / m ^2, preferably from 0.1 to 3 g / m ^2, more preferably from 0.2 to 2 g / m ^2.
(On-press development method)
Developing with fountain solution or fountain solution and printing ink on the printing apparatus of the present invention means non-image using fountain solution, fountain solution and printing ink at the stage of printing preparation on the press. By removing the portion, a so-called development process is performed on the printing apparatus.

  The removal of the non-image part (unexposed part) of the image forming layer on the printing press can be performed by contacting a watering roller or an ink roller while rotating the plate cylinder. Alternatively, it can be performed by various other sequences. In that case, the water amount may be adjusted by increasing or decreasing the amount of dampening water required for printing, and the water amount adjustment may be divided into multiple stages or steplessly. You may change it to.

  (1) As a sequence for starting printing, a watering roller is brought into contact with the plate cylinder to make one to several dozen rotations, then an ink roller is brought into contact with the plate cylinder to make one to several dozen rotations, and then Start printing.

  (2) As a sequence for starting printing, an ink roller is contacted to rotate the plate cylinder from 1 to several tens of turns, then a watering roller is contacted to rotate the plate cylinder from 1 to tens of rotations, 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.

  As the printing machine, generally known lithographic offset printing machines are used.

(Manufacture of lithographic printing plate materials)
Examples of the organic solvent used for forming the image forming layer of the printing plate material used in the present invention include alcohols (ethanol, propanol, etc.), cellosolves (methyl cellosolve, ethyl cellosolve), aromatics (toluene, Xylene, chlorobenzene, etc.), ketones (acetone, methyl ethyl ketone, etc.), ester solvents (ethyl acetate, butyl acetate, etc.), ethers (tetrahydrofuran, dioxane, etc.), halogen solvents (chloroform, dichlorobenzene, etc.), amides System solvents (for example, dimethylformamide, N-methylpyrrolidone, etc.) can be used.

  The formation of the image forming layer on the support can be carried out by, for example, applying and drying with an extrusion type extrusion coater. In order to increase the hardness of the surface of the image forming layer in order to obtain a high resolution image, May be calendared.

(Image exposure and printing method)
As the exposure light source used in the printing method of the present invention, a laser light source is used.

As a laser light source to be used, solid lasers such as ruby laser, YAG laser and glass laser, which are generally well known; He / Ne laser, Ar ion laser, Kr ion laser, CO ₂ laser, CO laser, He / Cd laser, Gas lasers such as N ₂ laser and excimer laser; semiconductor lasers such as InGaP laser, AlGaAs laser, GaAsP laser, InGaAs laser, InAsP laser, CdSnP2 laser, GaSb laser; chemical laser, dye laser, etc. Among them, a laser with a wavelength of 600 to 1500 nm can convert light energy into heat energy and is preferable in terms of sensitivity, and a laser with a wavelength of 700 to 1200 nm is more preferable.

  In the printing method of the present invention, the laser exposure is performed based on the image information, and then the process proceeds to a printing process without performing a special development process.

(Dampening water)
As the fountain solution used in the present invention, a fountain solution generally used for printing a planographic printing plate can be applied. Only water or an additive may be included.

  As the fountain solution, a fountain solution containing no conventionally used isopropanol is preferably used. In this case, “not contained” means that the content is less than 0.5%.

  An aqueous solution containing a surfactant is preferably used as the fountain solution.

  As the dampening water, tap water, well water, etc., which are generally obtained, can be used.

  The fountain solution contains, as a minor component, acids such as phosphoric acid or a salt thereof, citric acid or a salt thereof, nitric acid or a salt thereof, acetic acid or a salt thereof, and more specifically phosphoric acid, ammonium phosphate, phosphoric acid. Sodium, etc., citric acid, ammonium citrate, sodium citrate, acetic acid, ammonium acetate, sodium acetate and the like, and water-soluble polymer compounds such as carboxymethyl cellulose, carboxyethyl cellulose, etc.

  The content of these trace components is less than 0.1% by mass, preferably 0.05% by mass or less.

  Furthermore, glycol compounds such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol propyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene Glycol diethyl ether, dipropylene glycol dibutyl ether and the like can also be contained, and the content of these glycol compounds is also preferably small, less than 0.1% by mass, preferably 0.05% by mass or less.

  An aqueous solution containing a surfactant also exhibits the effects of the present invention.

  The surfactant is a nonionic surfactant, an anionic surfactant, a cationic surfactant, or these surfactants are a nonionic surfactant, an anionic surfactant, a cationic surfactant, or a mixed interface thereof. An activator is preferably used.

  Specific examples of the anionic surfactant include, for example, fatty acid salts, abietic acid salts, hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts, dialkyl sulfosuccinic acid salts, linear alkylbenzene sulfonic acid salts, alkylnaphthalene sulfonic acid salts, Alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salts, N-alkyl sulfosuccinic acid monoamide disodium salts, petroleum sulfone complex salts, sulfated castor oil, Sulfated tallow oil, sulfates of fatty acid alkyl esters, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl esters Sulfuric acid ester salts, polyoxyethylene styryl phenyl ether sulfuric acid ester salts, alkyl phosphoric acid ester salts, polyoxyethylene alkyl ether phosphoric acid ester salts, polyoxyethylene alkyl phenyl ether phosphoric acid ester salts, partial saponification of styrene and maleic anhydride copolymer And naphthalene sulfonate formalin condensates.

  Specific examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters , Sorbitan fatty acid partial esterified product, pentaerythritol fatty acid partial esterified product, propylene glycol monofatty acid ester, sucrose fatty acid partial esterified product, polyoxyethylene sorbitan fatty acid partial esterified product, polyoxyethylene sorbitol fatty acid partial ester Products, polyethylene glycol fatty acid esters, polyglycerol fatty acid partial esterified products, polyoxyethylenated castor oil, polyoxyethylene glycol Phosphorus fatty acid partial esterified products, fatty acid diethanolamides, N, N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, trialkylamine oxides, polyoxyethylene-poly Examples thereof include oxypropylene block polymers. Other fluorine-based surfactants and silicon-based surfactants can also be used.

  Specific examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, polyethylene polyamine derivatives, and the like.

  These surfactants may be used alone or in combination of two or more. The amount of the surfactant in the fountain solution is preferably 0.01% by mass or less, and more preferably 0.05% by mass or less.

As trace components, acids such as phosphoric acid or its salt, citric acid or its salt, nitric acid or its salt, acetic acid or its salt, more specifically, phosphoric acid, ammonium phosphate, sodium phosphate, citric acid Ammonium citrate, sodium citrate, acetic acid, ammonium acetate, sodium acetate and the like, and also include carboxymethyl cellulose, carboxyethyl cellulose, etc. as water-soluble polymer compounds. The content of these trace components is 0.1% by mass or less, preferably 0.05% by mass or less.
Furthermore, glycol compounds such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol propyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dibutyl ether, dipropylene glycol dimethyl ether, dipropylene Glycol diethyl ether, dipropylene glycol dibutyl ether and the like can also be contained, and the content of these glycol compounds is preferably a small amount, preferably 0.1% by mass or less, more preferably 0.05% by mass or less.

(Image forming method)
Image formation for producing a printing plate used in the printing method of the present invention can be performed by heat, but it is particularly preferable to perform image formation by exposure with an infrared laser.

  More specifically, the present invention relates to exposure used for producing a printing plate used for printing of the present invention, and more specifically, a laser that emits light in the infrared and / or near infrared region, that is, in the wavelength range of 700 to 1500 nm. The scanning exposure used is preferred. 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 according to the present invention, any apparatus can be used as long as it can form an image on the surface of a printing plate material in accordance with an image signal from a computer using the semiconductor laser. Good.

In general,
(1) A method of exposing the entire surface of the printing plate material by performing two-dimensional scanning using one or a plurality of laser beams on the printing plate material held by the plate-like holding mechanism,
(2) The circumferential direction of the cylinder (main scanning direction) using one or a plurality of laser beams from the inside of the cylinder to the printing plate material held along the cylindrical surface inside the fixed cylindrical holding mechanism ), Scanning the entire surface of the printing plate material by moving it in a 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 a plurality of laser beams from the outside of the cylinder. ) And moving in the direction perpendicular to the circumferential direction (sub-scanning direction) to expose the entire surface of the printing plate material.

  In the present invention, the scanning exposure method (3) is particularly preferable, and the exposure method (3) is used particularly in an apparatus that performs exposure on a printing apparatus.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, “parts” represents “parts by mass” unless otherwise specified.

Examples 1-18 and Comparative Examples 1-12
(Manufacture of aluminum support (base material 1))
A 0.24 mm-thick aluminum plate (material 1050, tempered H16) was immersed in a 5% aqueous sodium hydroxide solution maintained at 65 ° C., degreased for 1 minute, and then washed with water.

Next, in a 1% by mass hydrochloric acid aqueous solution maintained at 25 ° C., electrolytic polishing was performed with a carbon electrode at 40 ° C., a current of 20 A, 20 seconds (400 A · sec / dm ² ), and grained. After washing with water, subsequently, an immersion treatment (desmut treatment) was performed at 60 ° C. for 60 seconds with a 2% by weight aqueous caustic soda solution.

  Subsequently, anodization was performed under the following conditions.

  Bath: 30% by mass of sulfuric acid aqueous solution.

Current density: 2 A / dm ²
Processing temperature: 40 ° C
Treatment time: 60 seconds Subsequently, a 30-second immersion treatment is performed with hot water at 80 ° C. The substrate 1 was obtained by drying with hot air of 40 ° C.

  The roughness of the produced grain was measured with a surface roughness meter (RSTPLUS manufactured by WYKO). Ra was 0.34 μm.

(Preparation of planographic printing plate material 1)
(Preparation of image forming layer coating solution 1)
An image forming layer coating solution 1 having the composition shown in the following table was prepared. This image forming layer is an oleophilic layer that becomes hydrophilic by infrared laser exposure and can be developed with water or on-press.

The image forming layer coating solution 1 was applied to the substrate 1 so that the dry weight was 1.2 g / m ² and dried at 80 ° C. for 3 minutes to prepare a lithographic printing plate material 1.

(Image formation)
Image formation was performed by infrared laser exposure. A laser beam having a wavelength of 830 nm and a spot diameter of about 18 μm is used for exposure, and the laser beam is focused on the surface of the printing plate material. The exposure energy is 250 mJ / cm ² and 2400 dpi (dpi represents the number of dots per 2.54 cm). ) To form an image including a solid exposure part. On-press developability was evaluated in the solid exposure part.

(Printing method)
Printing machine: The lithographic printing plate material 1 was attached to the plate cylinder of DAIYA1F-1 manufactured by Mitsubishi Heavy Industries, Ltd., and printing was performed using the following dampening water and the following printing ink and paper. The printing start sequence was the PS printing sequence, and no special on-press development operation was performed.

<Dampening water>
Dampening water 1: Water (tap water) was used.

(Printing ink)
<< Manufacture of printing ink 1 (M) >> (magenta ink containing 20% by weight of soybean oil)
Resin (Rosin phenol resin; Beccasite F-181 <Dainippon Ink Chemical>)
45 parts flaxseed oil 14 parts No. 7 solvent (manufactured by Nippon Petroleum) 25 parts soybean oil 15 parts are charged into a reaction vessel, heated to 200 ° C., stirred for 1 hour to dissolve, and then aluminum chelate EB2 (Hope Pharmaceutical ( 1 part) was added and stirred at 180 ° C. for 1 hour to obtain a varnish for printing ink.

  60 parts of this varnish for printing, 20 parts of Carmine 6B (red pigment <Dainippon Ink Chemicals>), 7 parts of No. 7 solvent, 11 parts of soybean oil, and 2 parts of castor oil are kneaded by a conventional three-roll mill in a printing ink. 1 (M) was obtained.

<< Manufacture of printing inks 1 (Y), (C), (K) >>
A printing ink was produced in the same manner except that the pigment (carmine 6B) used in printing ink 1 (M) (magenta ink) was changed as follows. The amount of pigment added was finely adjusted to match the offset standard ink.

Printing ink 1 (Y) (yellow ink), pigment; dizazo yellow AAOT (color index (Pigment; Yellow-14, No; 21095))
Printing ink 1 (C) (cyan ink), pigment; phthalocyanine blue (color index (Blue-15, No; 74160)) Printing ink 1 (K) (black ink), pigment; carbon black (color index (Black-7) , No; 77266))
Paper : Coated paper (Mucoat <made by Hokuetsu Paper>)
(Evaluation of on-press developability)
The number of damaged paper sheets from the start of the printing sequence on the printing machine to the removal of the non-image area stains was measured. Further, the finished quality of the printed material when printing 1000 sheets and 10,000 sheets and the reproducibility of the shadow portion were evaluated. For the 100,000th sheet, the number of spot-like (circles having a diameter of 1 to 5 mm) spots scattered in the non-image area was counted.

Examples 2-24, Comparative Examples 1-12
Printing evaluation was performed in the same manner as in Example 1 except that the fountain solution and printing ink used in Example 1 were changed as follows.

(Printing ink 2-5)
Printing ink 2; ink containing 5% by weight of soybean oil printing ink 3; ink containing 50% by weight of soybean oil printing ink 4 (comparison); ink containing 3% by weight of soybean oil;
Printing ink 5 (comparison); ink containing 55% by weight of soybean oil (production of printing ink 2-5)
It changed into the following preparation ratio, and manufactured similarly to Example 1.

<Dampening water>
"Dampening water 1"
100 parts of tap water 《Dampening water 2》
Tap water 99.95 parts Phosphoric acid 0.04 parts Carboxymethyl cellulose 0.01 parts << Dampening water 3 >>
Tap water 99.94 parts Phosphoric acid 0.04 parts Carboxymethylcellulose 0.01 parts Sodium dodecylbenzenesulfonate 0.01 parts Dampening water 4
Tap water 99.8 parts Phosphoric acid 0.04 parts Carboxymethyl cellulose 0.01 parts Sorbitan monooleate 0.01 parts <Dampening water 5>
Tap water 99.8 parts Phosphoric acid 0.04 parts Carboxymethyl cellulose 0.01 parts Sodium dodecylbenzenesulfonate 0.01 parts Propylene glycol ethyl ether 0.04 parts fountain solution 6
Tap water 95.45 parts Isopropanol 4.5 parts Phosphoric acid 0.04 parts Carboxymethylcellulose 0.01 parts The ink and dampening water used in Examples 1 to 18 and Comparative Examples 1 to 12 are shown below.

Printing ink fountain solution Example 1 1 1
Example 2 1 2
Example 3 1 3
Example 4 1 4
Example 5 1 5
Example 6 1 6
Example 7 2 1
Example 8 2 2
Example 9 2 3
Example 10 2 4
Example 11 2 5
Example 12 2 6
Example 13 3 1
Example 14 3 2
Example 15 3 3
Example 16 3 4
Example 17 3 5
Example 18 3 6
Comparative Example 1 4 1
Comparative Example 2 4 2
Comparative Example 3 4 3
Comparative Example 4 4 4
Comparative Example 5 4 5
Comparative Example 6 4 6
Comparative Example 7 4 1
Comparative Example 8 5 2
Comparative Example 9 5 3
Comparative Example 10 5 4
Comparative Example 11 5 5
Comparative Example 12 5 6
The results are shown in Table 4.

Examples 19-24
(Preparation of planographic printing plate material 2)
(Preparation of thermal image-forming layer coating solution 2): An image-forming layer coating solution 2 having the composition shown in the following table was prepared. Using this coating solution, an image forming layer was coated on a substrate 2 produced in the same manner as in Example 1 except for the following conditions, and a lithographic printing plate material 2 was produced.

<< Substrate 2 >>
Electrolytic polishing bath: 25 ° C., 1 mass% hydrochloric acid aqueous solution Electrolytic conditions: 40 ° C., current 20 amps, 20 seconds (400 A · sec / dm ² ),
Surface roughness roughness Ra: 0.26 μm

  The same evaluation as in Example 1 was performed using the planographic printing plate 2. The printing ink and fountain solution used for printing are as follows.

Printing ink fountain solution Example 19 1 1
Example 20 1 2
Example 21 1 3
Example 22 1 4
Example 23 1 5
Example 24 1 6
The evaluation results are shown in Table 4. From Table 4, it can be seen that according to the present invention, the development speed on the printing press is high, and a printed matter with good dot reproducibility can be obtained without causing spot-like stains during printing.

  * 1: Number of damaged paper at start (on-machine development speed): Number of printed sheets until the non-image area is free from smudges.

  * 2 From the shadow part: The reproducibility of the shadow part (80-99%) of the printed pattern was visually evaluated with a loupe.

  A: No entanglement.

  ○: Although it is slightly entangled at the end, it is not visually recognized.

  Δ: Slightly entangled.

  X: Entangled.

  * 3: Finished quality: Visual evaluation of the printed solid part and the density of the net part, and visual evaluation of the halftone dot of the pattern part with a loupe.

  A: The ink density is high and the halftone dot fringe shape is smooth.

  ◯: Concentration is high, halftone dot fringe shape is somewhat sticky.

  (Triangle | delta): The ink density | concentration is high and the halftone dot fringe shape is sticking.

  X: The ink density is uneven and the halftone dot fringe shape is rough.

  * 4: Number of spot-like stains: Counts the number of spot-like stains (about 1-5mm) in the non-image area (the size of the printed non-image area is 400mm * 300mm (centered), non-image area) (Line area ratio is about 80%)

Claims (4)

In a printing method in which a lithographic printing plate material is exposed to an image with a laser beam and then developed and printed, a thermal image is formed on an aluminum support whose surface is electrolytically roughened in an electrolytic solution containing hydrochloric acid. A lithographic printing plate material having a layer, wherein the development is carried out on a printing apparatus using dampening water or dampening water and printing ink, and the printing ink used for the printing contains soybean oil in an amount of 5% by mass to 50% by mass. A printing method comprising a printing ink containing mass%. The printing method according to claim 1, wherein the fountain solution does not contain isopropanol. The printing method according to claim 1, wherein the fountain solution is an aqueous solution containing a surfactant. 4. The printing method according to claim 1, wherein the center line average roughness (Ra) of the surface of the aluminum support on the thermal image forming layer side is 0.20 to 0.4 μm.