JP2016182746A - Image correction method of photosensitive lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image correction method of a photosensitive lithographic printing plate capable of correcting a printing image by desensitization of an unwanted image part without generating ink smudges even when desensitization liquid adheres to a non-image part.SOLUTION: Polyethyleneimine, polyacrylic acid and a salt thereof and an inorganic fine particle are added to an unwanted image part after making a photosensitive lithographic printing plate having at least a hydrophilic layer containing an inorganic filler and a hydrophilic binder of 60 mass% or more based on total solid content of the hydrophilic layer and a photosensitive layer containing a compound having a polymerizable double bond group on the hydrophilic layer on a supporter.SELECTED DRAWING: None

Description

  The present invention relates to an image correction method for a photosensitive lithographic printing plate that corrects a printed image by desensitizing an unnecessary image portion of the photosensitive lithographic printing plate.

  In computer-to-plate (CTP) technology that outputs images directly on a printing plate based on digital data produced on a computer, full digitization has progressed due to the expansion of JDF (abbreviation of Job Definition Format). Therefore, work efficiency has been improved. However, a printing plate material (hereinafter also referred to as a CTP printing plate material) that can be made by CTP technology represented by the thermal type and photopolymer type, which are currently mainstream, is used after laser exposure of the lithographic printing plate material. The non-image part is eluted and removed using a developer containing a strong alkali agent, and then is generally subjected to plate making through steps such as washing with water and gumming. There is a need to switch to a system that considers human health and the environment. For this reason, technological development of a system aimed at so-called chemical-free, which eliminates chemicals including alkaline agents as much as possible from the developer for developing CTP printing plate materials, and no processing that does not require the development process itself has been carried out. It is active.

  In recent years, there has been proposed a photosensitive lithographic printing plate material that avoids the use of a developer containing a strong alkali agent and that can be developed with water or the like, that is, so-called chemical-free development. For example, in Japanese Patent Application Laid-Open No. 2003-215801 and Japanese Patent Application Laid-Open No. 2011-209354, a hydrophilic layer is provided on a roughened aluminum support having an anodized film and further silicate-treated, or a plastic film. A cationic water-soluble polymer having a phenyl group with a vinyl group substituted on the side chain, or a water-soluble polymer having a phenyl group and a sulfonate group with a vinyl group substituted on the side chain, and photopolymerization A photosensitive lithographic printing plate having a photosensitive layer containing an initiator or an acid generator is disclosed.

  Examples of the hydrophilic layer of the photosensitive lithographic printing plate that can be developed with water or the like, and that can be developed in a chemical-free manner, include, for example, JP 2008-265297 A, JP 2008-233820 A, and JP 2013. -88670, JP-A-2014-98777, and the like include a hydrophilic binder and an inorganic filler on the support, and the content of the inorganic filler is 60% by mass or more based on the total solid content of the hydrophilic layer. A certain hydrophilic layer (hereinafter also referred to as a hydrophilic layer mainly composed of an inorganic filler) is disclosed.

  In the above-described photosensitive lithographic printing plate, the photosensitive layer portion photopolymerized in the exposure step remains on the hydrophilic layer, and the other photosensitive layer portion is removed in the development step to expose the hydrophilic layer. Is obtained. The photosensitive layer portion on the hydrophilic layer functions as an image portion that selectively receives ink during printing, and the exposed hydrophilic layer functions as a non-image portion that selectively receives water during printing. However, if the photosensitive layer is not sufficiently removed in the development process described above, or if minor correction / deletion of the image after plate making is necessary, it is usually complicated to repeat the exposure process again, so correction of the printed image is usually performed. Work is done.

  Regarding the image correction method, a so-called correction liquid is generally used. For example, the image portion is removed by bringing an organic solvent or acid into contact with the image portion, or the surface of the unnecessary image portion is desensitized. To eliminate ink receptivity by doing

  The former method is described in, for example, Japanese Patent Publication No. 51-33442, Japanese Patent Application Laid-Open No. 55-121447, Japanese Patent Application Laid-Open No. 60-17748, and the like. However, when a lithographic printing plate having a hydrophilic layer mainly composed of an inorganic filler is brought into contact with a correction liquid containing an organic solvent or an acid, strong erosion or the like occurs on the hydrophilic layer, resulting in ink stains. There was a case. In addition, poor photodissolving of the photopolymerized photosensitive layer may occur, which is not satisfactory.

  On the other hand, in the latter method, it is important to maintain sufficient hydrophilicity for the desensitized image portion during the period of lithographic printing, and various studies have been made conventionally. . For example, JP 2002-307646 A (Patent Document 1) discloses a method for eliminating unnecessary image portions and stains on a lithographic printing plate having a hydrophilic layer containing a hydrophilic binder. JP-A-2003-118261 (Patent Document 2) contains a hydrophilic polymer having a silane coupling group at its terminal. The plate surface correction liquid characterized by this is described. However, sufficient effects could not be obtained in a lithographic printing plate having a hydrophilic layer mainly composed of an inorganic filler.

  JP-A-2003-287908 (Patent Document 3), JP-A-2006-347047 (Patent Document 4), JP-A-2007-79110 (Patent Document 5) and the like are modified to contain an organosilica sol. Although each of these solutions is shown, all of these methods are premised on dissolving and removing unnecessary image portions, and are sufficiently satisfactory when applied to a lithographic printing plate having a hydrophilic layer mainly composed of inorganic fillers. It wasn't possible. Furthermore, JP 2011-207138 A (Patent Document 6) discloses an image of a heat-sensitive lithographic printing plate on which an aqueous solution containing at least one water-soluble polymer compound having an amine structure and having a pH of 12 or more is applied. Although an erasing method is described, an aqueous solution adhering to a hydrophilic layer mainly composed of an inorganic filler has a problem that ink stains are liable to occur, and is not sufficiently satisfactory.

JP 2002-307646 A JP 2003-118261 A JP 2003-287908 A JP 2006-347047 A JP 2007-79110 A JP 2011-207138 A

  An object of the present invention is to desensitize an unnecessary image portion of a photosensitive lithographic printing plate so that a printed image at the time of performing lithographic printing can be corrected, and the desensitizing liquid is a non-image portion. It is an object of the present invention to provide a method for correcting an image of a photosensitive lithographic printing plate that does not cause ink smearing even when it adheres to the surface.

The problems of the present invention are solved by the following means.
(1) A hydrophilic layer containing 60% by mass or more of an inorganic filler and a hydrophilic binder with respect to the total solid content of the hydrophilic layer on the support, and a polymerizable double bond group on the hydrophilic layer. A photosensitive lithographic printing characterized in that polyethyleneimine, polyacrylic acid or a salt thereof, and inorganic fine particles are added to an unnecessary image portion after making a photosensitive lithographic printing plate having at least a photosensitive layer containing a compound having Version image correction method.

  According to the present invention, it is possible to correct a printed image when lithographic printing is performed by desensitizing an unnecessary image portion of the photosensitive lithographic printing plate, and the desensitizing liquid adheres to the non-image portion. In this case, it is possible to provide a method for correcting an image of a photosensitive lithographic printing plate that does not cause ink smearing.

  Hereinafter, the present invention will be described in detail.

  In the method for correcting an image of a photosensitive lithographic printing plate of the present invention, polyethyleneimine, polyacrylic acid or a salt thereof, and inorganic fine particles are formed on an unnecessary image portion of the lithographic printing plate after the plate making process (after the exposure process and the development process). Is granted.

  As a method for applying the above-described components, a desensitizing solution containing these is prepared, and this is applied to an unnecessary image portion using a applying means such as a brush, a brush, a pen, a cotton swab, or a dropper, and is dried. You can do it. However, when polyethyleneimine and inorganic fine particles coexist in the same liquid, an aggregate may be formed. Moreover, when desensitizing an unnecessary image part, it is preferable to provide an inorganic fine particle to an outermost part from a viewpoint of obtaining sufficient hydrophilicity. Therefore, in the present invention, it is preferable to apply the above three components to the unnecessary image portion by the following method (a) or (b).

(A): A desensitizing liquid (a1) containing polyethyleneimine and polyacrylic acid or a salt thereof is applied to an unnecessary image portion, and then a desensitizing liquid (a2) containing inorganic fine particles is applied.
(B): A desensitizing liquid (b1) containing polyethyleneimine is applied to an unnecessary image portion, and then a desensitizing liquid (b2) containing polyacrylic acid or a salt thereof and inorganic fine particles is applied.
In addition, when providing these two types of desensitizing liquid, it is preferable to provide a drying process between the processes.

  The desensitizing solution (a1) containing polyethyleneimine and polyacrylic acid or a salt thereof preferably has a pH of 10 or more. For the purpose of lowering the surface tension, the above-mentioned desensitizing liquid (a1) and the desensitizing liquid (b1) containing polyethyleneimine are nonionic surfactants such as polyoxyethylene alkyl ether and polyoxyethylene. An anionic surfactant represented by alkyl ether sulfuric acid can also be used in combination. Moreover, methanol, ethanol, etc. can be contained for the purpose of improving the drying property.

  On the other hand, the pH of the desensitizing liquid containing inorganic fine particles such as a desensitizing liquid (a2) containing inorganic fine particles, polyacrylic acid or a salt thereof, and a desensitizing liquid containing inorganic fine particles (b2) is 3 to 7 is preferable. Thereby, hydrophilicity can be effectively provided. As the pH adjuster, buffers such as phosphoric acid, polyphosphoric acid, phytic acid, citric acid, succinic acid, adipic acid, or salts thereof can be used.

  Examples of the polyethyleneimine described above are commercially available from Nippon Shokubai Co., Ltd., Epomin SP-012 (weight average molecular weight 1200), SP-018 (weight average molecular weight 1800), SP-200 (weight average molecular weight 10,000), Since SP-1000 (weight average molecular weight 70000) and the like can be easily obtained, they can be suitably used. Among these, when polyethyleneimine having a weight average molecular weight of 60000 or more is used, it is preferable because high hydrophilicity can be maintained over a long period of time. The content of the polyethyleneimine contained in the desensitizing solution (the above (a1) and (b1)) is preferably 10 to 200 g / L, more preferably 50 to 150 g / L.

  As polyacrylic acid or a salt thereof used in the present invention, polyacrylic acid having a weight average molecular weight of 1000 to 100,000 or a salt thereof can be suitably used. Examples of the salt include sodium salt and potassium salt. As such polyacrylic acid or a salt thereof, for example, various grades are commercially available from Nippon Shokubai Co., Ltd. as an aquaric series, and from Toa Gosei Co., Ltd. as an Aron series, and these can be obtained and used. . The preferable content of polyacrylic acid or a salt thereof contained in the desensitizing liquid ((a1) and (b2)) is 10 to 300 g / L, and more preferably 50 to 200 g / L.

  As the inorganic fine particles used in the present invention, inorganic fine particles having a peak particle size of 0.1 μm or less in a volume-based particle size distribution are preferable. For example, colloidal silica, alumina sol, zirconia sol, titania sol, and the like can be used. Of these, colloidal silica is most preferable. The colloidal silica may be in a form in which aluminum is adsorbed on the surface of fine particles. For example, Snowtex C, Snowtex CXS, Snowtex XS, Snowtex N, Snowtex commercially available from Nissan Chemical Industries, Ltd. 30, Snowtex ZL, Snowtex O, etc. are commercially available and can be used. In particular, colloidal silica having a peak particle size of 15 nm or less in the volume-based particle size distribution is preferred. The content of the inorganic fine particles contained in the desensitizing liquid ((a2) and (b2)) is preferably 5 to 200 g / L, more preferably 20 to 50 g / L in terms of solid content.

  Next, a photosensitive lithographic printing plate whose image is corrected according to the present invention will be described. Such a photosensitive lithographic printing plate has a hydrophilic layer containing 60% by mass or more of an inorganic filler and a hydrophilic binder with respect to the total solid content of the hydrophilic layer on the support, and a polymerizable property on the hydrophilic layer. It has at least a photosensitive layer containing a compound having a double bond group.

  As the support of the photosensitive lithographic printing plate, a metal plate represented by an aluminum plate, polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polystyrene, polyvinyl acetal, polycarbonate, cellulose diacetate, cellulose triacetate, propionic acid Representative examples include plastic films such as cellulose, cellulose butyrate, and cellulose nitrate. Particularly, polyethylene terephthalate and polyethylene naphthalate are preferably used.

  Further, the surface of the plastic film described above may be subjected to a surface treatment in order to improve adhesion with a hydrophilic layer or a backing layer provided as necessary. Examples of such surface treatment include corona discharge treatment, flame treatment, plasma treatment, and ultraviolet irradiation treatment. As a further surface treatment, an undercoat layer may be provided on the support in order to enhance adhesion with the hydrophilic layer provided on the support.

  The hydrophilic layer contains 60% by mass or more of an inorganic filler with respect to the total solid content of the hydrophilic layer. When the content of the inorganic filler is less than 60% by mass, sufficient printing durability and soil resistance may not be obtained. Examples of the inorganic filler contained in the hydrophilic layer include calcium carbonate, magnesium carbonate, zinc oxide, titanium dioxide, barium sulfate, aluminum hydroxide, zinc hydroxide, colloidal silica, pore silica, and kaolin. Of these, titanium dioxide, barium sulfate, aluminum hydroxide, and colloidal silica are preferable.

  Titanium dioxide may be either a rutile type or an anatase type, and the production method is not limited to either the sulfuric acid method or the chlorine method. You may use them individually or in mixture. Furthermore, from the viewpoint of dispersion stability and other functionality, it is possible to selectively use those subjected to various surface treatments. Examples of commercially available titanium dioxide include SR-1, R-650, R-5N, R-7E, R-3L, A-110, and A-190 from Sakai Chemical Industry Co., Ltd., Ishihara Sangyo Co., Ltd. Typeke R-580, R-930, A-100, A-220, CR-58 from Kronos KR-310, KR-380, KA-10, KA from Titanium Industry Co., Ltd. -20 etc., Titanics JR-301, JR-600A, JR-800, JR-701, etc. from Tyca Corporation, Taipure R-900, R-931, etc. from DuPont Corporation.

  As barium sulfate, it is preferable to use precipitated barium sulfate produced by adding a sulfate aqueous solution to a barium chlorine solution and chemically precipitating. Precipitated barium sulfate is commercially available, for example, as “Variace” from Sakai Chemical Industry Co., Ltd., having various particle diameters or surface-treated ones, any of which can be used.

  Aluminum hydroxide mixes bauxite, which is an ore containing alumina, with caustic soda or sodium aluminate solution, extracts the alumina component under high temperature and high pressure conditions, separates and removes red mud as a dissolution residue from the extract, A clarified sodium aluminate solution is obtained, and then seeds are added to the solution to crystallize aluminum hydroxide, and the obtained aluminum hydroxide can be pulverized. Various grades of aluminum hydroxide are commercially available as “Hijilite” from Showa Denko KK, and any grade can be used in the present invention.

  Colloidal silica is obtained by heating and aging a silica sol obtained by metathesis of sodium silicate with an acid or the like or through an ion exchange resin layer. Alternatively, it can also be produced by a liquid phase synthesis method such as hydrolysis of an alkoxide. For example, from Nissan Chemical Industries, Snowtex XS, Snowtex S, Snowtex 20, MP-2040, MP-1040, Snowtex ZL, Snowtex O, Snowtex OL, Snowtex UP, Snowtex PS-S, Snow Tex PS-M and the like are commercially available and can be used.

  Moreover, in the particle size distribution of the inorganic filler contained in the hydrophilic layer, the peak exists in the range of 0.2 μm or more and less than 0.6 μm and in the range of 0.6 μm or more and less than 1.5 μm, and 0.2 μm or more and 0.6 μm. When the distribution frequency of the inorganic filler existing in the range of less than fx is fx and the distribution frequency of the inorganic filler existing in the range of 0.6 μm or more and less than 1.5 μm is fy, the fx / fy ratio is 1.5 or more, The distribution frequency fy is preferably 25% or more. The fx / fy ratio is more preferably 2.0 or more, and the upper limit of the fx / fy ratio is less than 3.5. In the above-mentioned range, for example, when a plurality of peaks are present in the range of 0.2 μm or more and less than 0.6 μm, the distribution frequency fx may be obtained with the higher peak. In the case where the height of the recess between two peaks is 60% or more of the higher peak, it is regarded as one peak. As a result, a photosensitive lithographic printing plate excellent in soil resistance can be obtained.

  The above-mentioned particle size distribution is a volume-based particle size distribution, which is an index indicating what kind of particle size the sample particle group to be measured is and what ratio is configured, and is a publicly known publicly known It can be measured by the method. For example, a sieving method, a Coulter method (Coulter principle), a dynamic light scattering method, an image analysis method, a laser diffraction scattering method, etc. are known as the measuring method. In the present invention, the particle size to be measured and reproducibility are known. From the viewpoint of operability and the like, a laser diffraction / scattering method is preferably used. For example, it can be measured by LA-920 (laser diffraction / scattering type particle size distribution measuring apparatus) manufactured by Horiba, Ltd. The distribution frequency can be obtained as a distribution of the existence ratio for each size (particle diameter) based on the measurement result.

  The particle size distribution and distribution frequency in the present invention are measured by measuring the inorganic filler dispersed in the coating solution, or by measuring the inorganic filler in a solution obtained by re-dissolving the dried coating film of the applied hydrophilic layer with an alkali. You can ask for it. As will be described later, in the present invention, two or more kinds of inorganic fillers can be used together. However, in the laser diffraction scattering method preferably used in the present invention, the light intensity distribution pattern is obtained from the Fraunhofer diffraction theory and the Mie scattering theory. Therefore, a refractive index specific to the object is required, and it is difficult to accurately measure the particle size distribution and distribution frequency of a coating liquid containing two or more inorganic fillers having different refractive indexes. However, in such a case, the particle size distribution and distribution frequency of each inorganic filler alone are measured in advance, and two or more kinds of inorganic fillers are added by multiplying the obtained measurement result by the addition ratio in the coating liquid as a coefficient. The particle size distribution and distribution frequency of the coating liquid used in combination can be determined.

  In order to obtain the particle size distribution of the inorganic filler described above, an inorganic filler having an average primary particle size of 0.1 μm or more and less than 0.6 μm and an inorganic filler having an average primary particle size of 0.6 μm or more and less than 2.0 μm are combined. It is preferable to use it, and if it is such a combination, the inorganic filler may be further used in combination with three or four kinds. The addition amount of the inorganic filler is preferably 60% by mass or more, more preferably 70% by mass or more, based on the total solid content of the hydrophilic layer.

  In addition, it is desirable that the content of the silicon-containing compound is small in the entire inorganic filler having the above particle size distribution. The silicon-containing compound is colloidal silica, pore silica, kaolin, or the like, and is preferably used at 5% by mass or less, more preferably 3% by mass or less, particularly 1% by mass with respect to the total inorganic filler. It is desirable to use in the following. Thereby, a lithographic printing plate support excellent in developability is obtained.

  The hydrophilic layer of the present invention further contains a hydrophilic binder in addition to the above-described inorganic filler. Examples of such hydrophilic binders include proteins such as gelatin and gelatin derivatives, or cellulose derivatives, gum arabic, starch and derivatives thereof, cellulose derivatives (for example, hydroxypropylmethylcellulose), polysaccharides such as glycogen, agarose, pectin, dextran, and pullulan. Examples thereof include synthetic polymer compounds such as polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, styrene / maleic acid copolymer salt, styrene / acrylic acid copolymer salt, and acrylamide polymer.

  Other components that can be contained in the hydrophilic layer include, for example, melamine resin, epoxy resin, polyisocyanate compound, aldehyde compound, silane compound, chromium alum, divinylsulfone, etc. for the purpose of improving the film strength and adhesive strength of the hydrophilic layer. For example, polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyls for the purpose of improving the coating properties of coating solutions containing a high concentration of the inorganic filler in the hydrophilic layer. Anionic surfactants such as ether sulfates, fatty acid alkylbetaine amphoteric surfactants such as coconut oil fatty acid amidopropyl betaine, lauric acid amidopropyl betaine, myristic acid amidopropyl betaine, octanoic acid amidopropyl betaine, lauryldimethylaminoacetic acid , Steari Alkylbetaine-type amphoteric surfactants such as dimethylaminoacetic acid, sulfobetaine-type amphoteric surfactants such as dodecylaminomethyldimethylsulfopropylbetaine, octadecylaminomethyldimethylsulfopropylbetaine, sodium lauroylglutamate, potassium lauroylglutamate, lauroylmethyl-β -Amino acid type amphoteric surfactants such as alanine, and amine oxide type amphoteric surfactants such as lauryldimethylamine N-oxide and oleyldimethylamine N-oxide can be contained.

  Next, the photosensitive layer containing a compound having a polymerizable double bond group will be described.

  The compound having a polymerizable double bond group can be used by mixing one or two or more compounds selected from a group of high molecular compounds and low molecular compounds.

  The polymer compound having a polymerizable double bond group is a polymer compound formed by an arbitrary repeating unit, and is a polymer compound in which a polymerizable double bond group is bonded to a side chain through an arbitrary linking group. is there. Among them, a polymer compound having a vinyl group as a polymerizable double bond group is preferably used, and a polymer compound in which a phenyl group substituted with a vinyl group is bonded to the main chain directly or via an arbitrary linking group is particularly preferably used. It is done. In addition, it is preferable to introduce a carboxyl group, a sulfo group, a quaternary ammonium group, or the like linked to the main chain via an arbitrary linking group, but among them, a polymer compound having a sulfo group is preferably used because of its high developability. be able to. The sulfo group may form a salt (for example, sodium salt, potassium salt, lithium salt, ammonium salt, etc.). These linking groups are not particularly limited, and include any group, atom, or a combination thereof. The phenyl group and sulfo group substituted with a vinyl group may be independently bonded to the main chain, or the phenyl group substituted with a vinyl group and the sulfo group share part or all of the linking group. You may combine with.

  In the phenyl group substituted by the vinyl group, the phenyl group may be substituted, and the vinyl group is a halogen atom, carboxyl group, sulfo group, nitro group, cyano group, amide group, amino group, alkyl group. , An aryl group, an alkoxy group, an aryloxy group and the like may be substituted.

  With respect to the polymer compound having a polymerizable double bond group, for example, JP 2012-203131, JP 2012-208152, JP 2012-208331, JP 2012-208332, JP 2013. -20103 and the like, and can be used in the present invention.

  Next, a low molecular compound having a polymerizable double bond group will be described. The low molecular compound having a polymerizable double bond group in this case can be preferably used as long as it is a compound that undergoes polymerization by radicals generated by photolysis of a photopolymerization initiator. Furthermore, when a compound having two or more polymerizable double bond groups in the molecule is used, a crosslinked product is formed as a result of polymerization by radicals. Therefore, a negative photosensitive lithographic printing plate material is used. When constituted, it forms a cross-linked hard image part film, so that it can be used very preferably to give a printing plate excellent in printing durability and ink transferability. Examples of compounds having a polymerizable double bond group that can be used for such purposes include 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and tetraethylene glycol diacrylate. Polyfunctional acrylic monomers such as trisacryloyloxyethyl isocyanurate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, etc., or acryloyl group, methacryloyl group Polyester (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, etc. are also used in the same way as various oligomers introduced with That.

  Examples of other elements constituting the photosensitive layer of the photosensitive lithographic printing plate used in the present invention include a photopolymerization initiator. Conventionally known compounds can be used as the photopolymerization initiator. For example, trihaloalkyl-substituted compounds (for example, s-triazine compounds and oxadiazole derivatives as trihaloalkyl-substituted nitrogen-containing heterocyclic compounds, trihaloalkylsulfonyl compounds), organic boron salts, hexaarylbiimidazoles, titanocene compounds, thios Examples thereof include compounds and organic peroxides. Among these photopolymerization initiators, trihaloalkyl-substituted compounds and organic boron salts are particularly preferably used. More preferably, a combination of a trihaloalkyl-substituted compound and an organic boron salt is used. A combination of a trihaloalkyl-substituted compound and an organic boron salt is preferable because sensitivity can be further improved.

  The trihaloalkyl-substituted compound that is a photopolymerization initiator is specifically a compound having at least one trihaloalkyl group such as a trichloromethyl group or a tribromomethyl group in the molecule. Preferred examples include the trihaloalkyl group. S-triazine derivatives and oxadiazole derivatives may be mentioned as compounds in which is bonded to a nitrogen-containing heterocyclic group, or trihaloalkylsulfonyl in which the trihaloalkyl group is bonded to an aromatic ring or a nitrogen-containing heterocyclic ring via a sulfonyl group Compounds.

  Further, the photosensitive layer preferably contains a compound for sensitizing the above-mentioned photopolymerization initiator. As compounds that increase the sensitivity in the wavelength region of 400 to 430 nm, cyanine dyes, coumarin compounds described in JP-A-7-271284, JP-A-8-29973, etc., JP-A-9-230913, Carbazole compounds described in JP-A No. 2001-42524 and the like, carbomerocyanine dyes described in JP-A-8-262715, JP-A-8-272096, JP-A-9-328505, and the like, JP-A-4-194857, JP-A-6-295061, JP-A-7-84863, JP-A-8-220755, JP-A-9-80750, JP-A-9-236913, etc. Aminobenzylidene ketone dyes, JP-A-4-184344, JP-A-6-301208, The pyromethine dyes described in Kaihei 7-225474, JP-A-7-5585, JP-A-7-281434, JP-A-8-6245, etc., and JP-A-9-80751 Styryl dyes or (thio) pyrylium compounds. Of these, cyanine dyes, coumarin compounds or (thio) pyrylium compounds are preferred.

  The photosensitive layer of the photosensitive lithographic printing plate used in the present invention preferably contains a silane coupling agent. An excellent printing durability can be obtained when the photosensitive layer contains a silane coupling agent. However, in the photosensitive lithographic printing plate having the hydrophilic layer described above, the stain resistance, the antifogging property, and the ink detachment property are eliminated. This is particularly preferable because the printing durability is improved without lowering the separation property.

  Examples of silane coupling agents include epoxycyclohexylethyltrimethoxysilane, glycidoxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, methacryloxypropyltrimethoxysilane, mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, methyltri Methoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, styryltrimethoxysilane, styryltriethoxysilane, hexyltrimethoxysilane , Decyltrimethoxysilane, vinyltris (3-methoxyethoxy) silane, vinyltriet Sisilane, vinyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3 -Glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β ( Aminoethyl) -aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-chloro B pills trimethoxysilane, 3-isocyanatopropyltriethoxysilane, etc. it is possible to contain. Among them, epoxycyclohexylethyltrimethoxysilane, glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, acryloxypropyltrimethoxysilane, methacryloxypropyltrimethoxysilane, mercaptopropyltrimethoxysilane, mercaptopropyltri Particularly preferred are trialkoxysilanes such as ethoxysilane. In addition, a silane coupling agent may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  The photosensitive layer is preferably a layer formed by applying and drying an aqueous coating solution containing at least an emulsion in water of a compound having a photopolymerization initiator and a polymerizable double bond group. In preparing an emulsion in water containing the above-mentioned components, a photopolymerization initiator and a compound having a polymerizable double bond group are emulsified and dispersed in water in the presence of an anionic surfactant, so that they are exposed to a certain high temperature. However, it is preferable because an underwater emulsion capable of stably maintaining an emulsified dispersion state can be obtained. In addition, it is preferable from the viewpoint of storage stability of the coating liquid that a photopolymerization initiator, a compound having a polymerizable double bond group, and a sensitizing dye are emulsified and dispersed in water in the presence of an anionic surfactant.

  Examples of anionic surfactants used for emulsification and dispersion include higher fatty acid salts such as sodium laurate, sodium stearate and sodium oleate, alkyl sulfates such as sodium dialkylsulfosuccinate, sodium lauryl sulfate and sodium stearyl sulfate, and octyl. Sodium alcohol sulfate, sodium lauryl alcohol sulfate, higher alcohol sulfates such as ammonium lauryl alcohol sulfate, aliphatic alcohol sulfates such as sodium acetyl alcohol sulfate, alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate, Alkyl naphthalene sulfones such as sodium butyl naphthalene sulfonate and sodium isopropyl naphthalene sulfonate Salts, alkyl diphenyl ether disulfonates such as sodium alkyl diphenyl ether disulfonate, alkyl phosphate esters such as sodium lauryl phosphate and sodium stearyl phosphate, polyethylene oxide adduct of sodium lauryl ether sulfate, polyethylene oxide adduct of ammonium lauryl ether sulfate, lauryl ether Polyethylene oxide adducts of alkyl ether sulfates such as polyethylene oxide adduct of triethanolamine sulfate, polyethylene oxide adducts of alkyl phenyl ether sulfates such as polyethylene oxide adduct of sodium nonylphenyl ether sulfate, sodium lauryl ether phosphate Polyether of alkyl ether phosphate such as polyethylene oxide adduct Alkylene oxide adducts, and polyethylene oxide adducts, and the like alkyl phenyl ether phosphate polyethylene oxide adduct of nonyl phenyl ether sodium phosphate. Of these, sodium dialkylsulfosuccinate, alkyl naphthalene sulfonates, and polyethylene oxide adducts of alkyl ether sulfates are particularly preferable because of the most improved dispersion stability.

  In addition, the dispersion stability of the emulsion in water is further improved by adding the above-described polymer compound having a polymerizable double bond group and a sulfo group that forms a salt to the system and emulsifying and dispersing. Since the polymer compound is water-soluble, it may be added at the time of emulsification dispersion for preparing an emulsion in water, or may be added after emulsification dispersion. Since the dispersed particle diameter is remarkably reduced and dispersed in the form of extremely fine droplets and fine particles, problems such as sedimentation or levitation over time are suppressed, which is more preferable. Furthermore, a part of the polymer compound may be used at the time of dispersion to prepare a dispersion, and after the stable dispersion is prepared, the polymer compound may be preferably added.

  The dispersion method for emulsifying and dispersing is not particularly limited, and any disperser such as a rotary disperser, a media mill such as a bead mill or a ball mill, an ultrasonic disperser or a kneader can be used. A commercially available apparatus such as a homogenizer or a sand grinder can be preferably used.

  In preparing an emulsion in water, a compound having a photopolymerization initiator and a polymerizable double bond group is dissolved in advance in an organic solvent, or a photopolymerization initiator and a polymerizable double bond group are previously dissolved in an organic solvent. After dissolving a compound having a sensitizing dye and a sensitizing dye, an emulsion is prepared by the dispersion method described above, and an organic solvent is removed from the emulsion by distillation to prepare an underwater emulsion in which fine particles are dispersed in water. Is preferred. The organic solvent that can be used may be any organic solvent that is liquid at room temperature and can dissolve or disperse a compound having a polymerizable double bond group, a photopolymerization initiator, or a sensitizing dye. Examples of organic solvents include volatile organic solvents and non-volatile organic solvents. When a volatile organic solvent is used, it is preferably removed from the system by heating or leaving the volatile organic solvent from the produced dispersion. In the case of using a non-volatile organic solvent, the non-volatile organic solvent exhibits a flash point higher than 50 ° C., which may reduce countermeasures as a dangerous substance in normal handling, which is preferable.

  Specific examples of the volatile organic solvent include, for example, acetates of lower alkanols such as ethyl acetate, propyl acetate and butyl acetate, ethylene glycol acetates such as ethylene glycol monomethyl ether acetate and ethylene glycol monoethyl ether acetate. , Ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, hydrocarbons such as hexane, cyclohexane and heptane, and aromatics such as benzene, toluene and xylene, etc., and ethyl acetate is most preferably used.

  Nonvolatile organic solvents include phosphoric acid esters, phthalic acid esters, acrylic acid esters, methacrylic acid esters and other carboxylic acid esters, fatty acid amides, alkylated biphenyls, alkylated terphenyls, alkylated naphthalenes, diarylethanes, chlorinated paraffins, Examples include alcohol solvents, phenol solvents, ether solvents, monoolefin solvents, and epoxy solvents. Specific examples include tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, tricyclohexyl phosphate, dibutyl phthalate, dioctyl phthalate, dilaurate phthalate, dicyclohexyl phthalate, butyl olefinate, diethylene glycol benzoate, dioctyl sebacate, Dibutyl sebacate, dioctyl adipate, trioctyl trimellitate, acetyl triethyl citrate, octyl maleate, dibutyl maleate, isoamylbiphenyl, chlorinated paraffin, diisopropylnaphthalene, 1,1'-ditolylethane, monoisopropylbiphenyl, diisopropylbiphenyl, 2,4-ditertiaryamylphenol, N, N-dibutyl-2-butoxy-5-tertiaryoctylaniline, hydroxy Ikikosan ethylhexyl esters, high boiling point solvent such as polyethylene glycol.

  More preferably, the organic solvent used when preparing the emulsion in water is a volatile organic solvent. In this case, it is preferable because an underwater emulsion having the most stable dispersion state can be produced and the dispersion state can be kept stable even when exposed to a temperature higher than room temperature. As the volatile organic solvent, ethyl acetate is particularly preferable. Since ethyl acetate is highly volatile, it can be distilled off simply by placing it under heating or under reduced pressure. The emulsion in water after distillation of ethyl acetate is in a solid dispersion state and contains an organic solvent such as ethyl acetate. This is extremely preferable because it forms an aqueous coating solution that is more stable than the state. In the present invention, the aqueous coating solution means that water accounts for 50% by mass or more as a liquid medium component in the coating solution, and more preferably 80% by mass or more.

  Further, in the photosensitive lithographic printing plate used in the present invention, a protective layer is preferably provided on the photosensitive layer. The protective layer prevents exposure of low molecular weight compounds such as oxygen and basic substances present in the atmosphere that hinder the image formation reaction caused by exposure in the photosensitive layer to further improve exposure sensitivity in the atmosphere. It has a favorable effect of improving. Furthermore, an effect of preventing the photosensitive layer surface from scratches is also expected. Therefore, the properties desired for such a protective layer are low permeability of low molecular weight compounds such as oxygen and excellent mechanical strength, and further, transmission of light used for exposure is not substantially inhibited, and the photopolymerizable photosensitive layer and It is desirable that it has excellent adhesiveness and can be easily removed in the development step after exposure.

  Such a device relating to the protective layer has been conventionally devised, and is described in detail in US Pat. No. 3,458,311 and JP-A-55-49729. As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used. Specifically, polyvinyl alcohol, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, and polyacrylic are used. Water-soluble polymers such as acids are known, and among these, using polyvinyl alcohol as a main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability. The polyvinyl alcohol used for the protective layer may be partially substituted with an ester, an ether and an acetal as long as it contains an unsubstituted vinyl alcohol unit for having necessary oxygen barrier properties and water solubility. Similarly, some of them may have other copolymer components.

As a light source used for exposure for forming an image pattern on the above-described photosensitive lithographic printing plate, a carbon arc, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a low pressure mercury lamp, a deep UV lamp, a xenon lamp, a metal halide lamp, a tungsten lamp, a halogen lamp Excimer UV lamps, LED lamps, various fluorescent lamps and the like (white fluorescent lamps, black lights, chemical lights, etc.) can be used, but scanning exposure with a laser is very preferable in terms of plate making efficiency. Examples of the laser light source include a blue-violet semiconductor laser (violet laser), an argon laser, a helium / neon laser, a red LED, a near infrared laser, and an infrared laser. Among them, GaN having a wavelength region of 390 to 430 nm is preferably used from the viewpoint of productivity and image definition. The scanning method may be any of an internal drum system, an external drum system, a planar scanning system, etc., but an internal drum system is preferred. Further, the laser intensity at the plate surface is preferably set to 1~600μJ / cm ^2, particularly preferably in the 30~400μJ / cm ^2.

  The development method of the above-described photosensitive lithographic printing plate is preferably a temperature of about 10 to 60 ° C., more preferably about 15 to 45 ° C., by a known development method such as immersion development, spray development, brush development, or ultrasonic development. In about 5 seconds to 10 minutes. At that time, the protective layer provided as necessary on the photosensitive layer may be removed in advance with water or the like, or may be removed during development.

  The plate making method of the photosensitive lithographic printing plate can be usually developed by a known alkali developer by the above developing method. In the case where the polymer compound having a polymerizable double bond group described above has an acidic group such as a carboxy group or a sulfo group, and the acidic group is in the form of a metal salt or an ammonium salt in the photosensitive layer. , Ion-exchanged water, tap water, industrial water or the like can be used for the development treatment.

  EXAMPLES Hereinafter, although this invention is demonstrated using an Example, this invention is not limited by this description. In the following description, “%” and “part” are based on mass unless otherwise specified.

<Preparation of photosensitive lithographic printing plate>
On a polyethylene terephthalate film having a thickness of about 200 μm, a hydrophilic layer coating solution having the following composition was applied by a slide hopper coating method. At that time, the application was performed in advance so that the moisture application amount was 35 g / m ² . Immediately after coating, the coating film was gelled with cold air of 1 to 5 ° C., and then dried using a dry air set at 50 ° C. After drying, the hydrophilic layer was completed by putting it in a thermo-hygrostat adjusted to 40 ° C. and 40% RH and heating for 7 days.

<Hydrophilic layer coating solution>
Alkali-treated gelatin 1.2 parts Inorganic filler 1: Titanium dioxide 4.0 parts (TISR1, manufactured by Sakai Chemical Industry Co., Ltd., average primary particle size≈0.3 μm, relative refractive index≈2.04)
Inorganic filler 2: 1.6 parts of barium sulfate (B35, manufactured by Sakai Chemical Industry Co., Ltd., average primary particle size≈0.3 μm, relative refractive index≈1.23)
Inorganic filler 3: 0.4 part of aluminum hydroxide (H42, manufactured by Showa Denko KK, average primary particle size≈1.0 μm, relative refractive index≈1.24)
Dispersant (acrylic acid copolymerized metal salt, 10% solution) 1.0 part Surfactant: 0.4 part of polyoxyethylene lauryl ether sodium acetate (Daiichi Kogyo Seiyaku Co., Ltd. Neo Haitenol ECL-45 10% solution) )
Chelating agent: sodium triethylenetetramine hexaacetate 0.1 part Hardener (divinylsulfone, 5% solution) 4.0 part Adjust the pH to 7.0 with 1N sulfuric acid and add 35 parts by weight with water. It was.

  Regarding the particle size distribution and distribution frequency of the inorganic filler contained in the hydrophilic layer coating liquid, the inorganic fillers 2 and 3 contained in the hydrophilic layer coating liquid are not added, and the inorganic filler is inorganic in the hydrophilic layer coating liquid. A coating solution in which the filler 1 is present alone is prepared, and a coating solution in which the inorganic fillers 2 and 3 are present in the hydrophilic layer coating solution is prepared in the same manner. The particle size distribution and the distribution frequency were measured using a laser diffraction / scattering particle size distribution measuring apparatus (LA920 manufactured by Horiba, Ltd.), and the particle size distribution of each obtained single dispersion was multiplied by the addition ratio as a coefficient, The particle size distribution and distribution frequency of the hydrophilic layer coating solution were calculated. As a result, the distribution frequency fx of the inorganic filler existing in the range of 0.2 μm or more and less than 0.6 μm is 64.8%, and the distribution frequency fy of the inorganic filler existing in the range of 0.6 μm or more and less than 1.5 μm is It was 30.1% and fx / fy was 2.15.

<Photosensitive layer>
On the hydrophilic layer obtained above, the following photosensitive layer coating solution was applied such that the solid content was 1.5 g / m ^2, and after application, dried in a 75 ° C. drier for 10 minutes.

<Photosensitive layer coating solution>
Liquid compositions A and B having the following compositions were prepared.
<Liquid composition A>
300 parts of ion-exchanged water High molecular compound having a polymerizable double bond group (formula 1 / weight average molecular weight 200,000)
20.0 parts Anionic surfactant (sodium dialkylsulfosuccinate) 5.0 parts (Perex OT-P: manufactured by Kao Corporation)
Colorant (Pigment Blue 15) 0.2 part

<Liquid composition B>
Trimethylolpropane triacrylate 6.0 parts Photopolymerization initiator (Chemical formula 2) 2.0 parts Trihaloalkyl-substituted compound (Chemical formula 3) 1.5 parts 3-acryloxypropyltrimethoxysilane 0.5 parts Sensitizing dye (Chemical formula) 4) 0.05 part 200 parts of ethyl acetate was added and dissolved.

  Liquid composition A was charged into a vacuum emulsifier PVQ-1D (manufactured by Mizuho Kogyo Co., Ltd.) and the rotation speed of the homomixer was set to 5000 rpm. Then, liquid composition B was charged into the vacuum emulsifier and homogenized at room temperature. The mixer was stirred at high speed for 20 minutes to carry out emulsification dispersion. Thereafter, the inside of the vacuum emulsification apparatus is reduced in pressure using an aspirator, the temperature is raised to 50 ° C. under a reduced pressure condition of 20% of atmospheric pressure, and ethyl acetate is distilled off under reduced pressure to form a photopolymerizable photosensitive layer coating solution. did. From the amount of ethyl acetate collected in the cooler, it was confirmed that all the ethyl acetate used was distilled off from the emulsion in water.

<Protective layer>
A coating solution is prepared according to the following protective layer formulation, and applied to the photopolymerizable photosensitive layer so that the solid content is 1.5 g / m ^2. After coating, the coating solution is dried in a dryer at 75 ° C. for 10 minutes. A photosensitive lithographic printing plate was obtained.

<Protective layer prescription>
Polyvinyl alcohol PVA-102 (manufactured by Kuraray Co., Ltd.) 1 part Surfactant (POE nonylphenyl ether sulfate, 10% solution) 0.4 part Ion exchange water 9 parts

<Exposure / Development>
The photosensitive lithographic printing plate obtained above was exposed to a test chart image using a blue-violet semiconductor laser emitting at 405 nm (output: 120 mW) as an exposure light source and setting the plate surface exposure energy to 200 μJ / cm ² . Thereafter, the film was immersed in ion exchange water at 25 ° C. for 15 seconds, and the surface having the photopolymerizable photosensitive layer / protective layer was rubbed and developed with cellulose sponge.

<Image correction processing>
(Comparative Example 1)
A desensitizing liquid 1 was obtained by adding Epomin P-1000 (weight average molecular weight 70000) manufactured by Nippon Shokubai Co., Ltd. to pure water so as to be 100 g / L in solid content as polyethyleneimine. The obtained desensitizing solution 1 was applied to a part of the image portion and non-image portion of the planographic printing plate with a cotton swab and dried.

(Comparative Example 2)
Aaron T-50 (weight average molecular weight 6000) manufactured by Toa Gosei Co., Ltd. was added to pure water as sodium polyacrylate so as to have a solid content of 100 g / L to obtain a desensitizing solution 2. The obtained desensitizing solution 2 was applied to a part of the image portion and non-image portion of the planographic printing plate with a cotton swab and dried.

(Comparative Example 3)
As a polyvinyl alcohol, PVA-117 manufactured by Kuraray Co., Ltd. was added to pure water so as to have a solid content of 1 g / L to obtain a desensitizing solution 3. The obtained desensitizing liquid 3 was applied to a part of the image portion and non-image portion of the planographic printing plate with a cotton swab and dried.

(Comparative Example 4)
As a polyacrylamide, a reagent (weight average molecular weight 10,000) manufactured by Wako Pure Chemical Industries, Ltd. was added to pure water so as to have a solid content of 1 g / L to obtain a desensitizing solution 4. The obtained desensitizing solution 4 was applied to part of the image portion and non-image portion of the planographic printing plate with a cotton swab and dried.

(Comparative Example 5)
A desensitizing liquid 5 was obtained by adding Snowtex C (solid content 20%) manufactured by Nissan Chemical Industries, Ltd. to pure water so that it was 250 g / L and monosodium phosphate was 100 g / L. After applying the desensitizing solution 1 obtained in Comparative Example 1 to a part of the image portion and non-image portion of the planographic printing plate with a cotton swab and drying, the above-described desensitizing solution 5 is applied to the same portion with a cotton swab. It was applied and dried.

(Comparative Example 6)
Apply the above-described desensitizing solution 2 to a part of the image portion and non-image portion of the planographic printing plate with a cotton swab and dry, and then apply the above-described desensitizing solution 5 to the same portion with a cotton swab and dry it. I let you.

(Comparative Example 7)
The above-described desensitizing solution 3 is applied to a part of the image portion and non-image portion of the lithographic printing plate with a cotton swab and dried, and then the above-described desensitizing solution 5 is similarly applied to the same portion with a cotton swab and dried. I let you.

(Comparative Example 8)
After applying the desensitizing solution 4 to a part of the image portion and the non-image portion of the planographic printing plate with a cotton swab and drying, the above-described desensitizing solution 5 is similarly applied to the same portion with a cotton swab and dried. I let you.

Example 1
As a polyethyleneimine, Nippon Shokubai Co., Ltd. Epomin P-1000 (weight average molecular weight 70000) is 50 g / L in solid content, and Toa Gosei Co., Ltd. Aaron T-50 (weight average molecular weight 6000) in solid content is used as sodium polyacrylate. It added to the pure water so that it might be set to 50 g / L, and the desensitizing liquid 6 was obtained. After applying the obtained desensitizing liquid 6 to a part of the image portion and non-image portion of the planographic printing plate with a cotton swab and drying, the above-described desensitizing liquid 5 was similarly applied to the same portion with a cotton swab, Dried.

(Example 2)
As a polyethyleneimine, Nippon Shokubai Co., Ltd. Epomin P-1000 (weight average molecular weight 70,000) is 100 g / L in solid content, and as sodium polyacrylate, Toa Gosei Co., Ltd. Aron T-50 (weight average molecular weight 6000) is in solid content. It added to the pure water so that it might be set to 50 g / L, and the desensitizing liquid 7 was obtained. The obtained desensitizing solution 7 was applied to a part of the image portion and the non-image portion of the planographic printing plate with a cotton swab, and after drying, the above-described desensitizing solution 5 was similarly applied to the same portion with a cotton swab, Dried.

Example 3
As a polyethyleneimine, Nippon Shokubai Co., Ltd. Epomin P-1000 (weight average molecular weight 70,000) is 150 g / L in solid content, and as polyacrylic acid, Toa Gosei Co., Ltd. Aron T-50 (weight average molecular weight 6000) is used in solid content. It added to the pure water so that it might be set to 50 g / L, and the desensitizing liquid 8 was obtained. After applying the obtained desensitizing liquid 8 to a part of the image part and non-image part of the lithographic printing plate with a cotton swab and drying, the above-described desensitizing liquid 5 is similarly applied to the same part with a cotton swab, Dried.

Example 4
As a polyethyleneimine, Nippon Shokubai Co., Ltd. Epomin P-1000 (weight average molecular weight 70,000) is 150 g / L in solid content, and as polyacrylic acid, Toa Gosei Co., Ltd. Aron T-50 (weight average molecular weight 6000) is used in solid content. It added to the pure water so that it might be set to 100 g / L, and the desensitizing liquid 9 was obtained. After applying the obtained desensitizing solution 9 to a part of the image portion and non-image portion of the planographic printing plate with a cotton swab, and drying, the above-described desensitizing solution 5 is similarly applied to the same portion with a cotton swab, Dried.

(Example 5)
As a polyethyleneimine, Nippon Shokubai Co., Ltd. Epomin P-1000 (weight average molecular weight 70,000) is 150 g / L in solid content, and as polyacrylic acid, Toa Gosei Co., Ltd. Aron T-50 (weight average molecular weight 6000) in solid content. It added to the pure water so that it might become 200 g / L, and the desensitizing liquid 10 was obtained. After applying the obtained desensitizing solution 10 to a part of the image portion and non-image portion of the planographic printing plate with a cotton swab and drying, the above-described desensitizing solution 5 was similarly applied to the same portion with a cotton swab, Dried.

(Example 6)
A desensitizing liquid 12 was obtained in which Snowtex C (solid content 20%) manufactured by Nissan Chemical Industries, Ltd. was added to pure water so as to be 100 g / L and monosodium phosphate was 100 g / L. After applying the above-described desensitizing solution 6 to a part of the image portion and non-image portion of the planographic printing plate with a cotton swab and drying, the above-described desensitizing solution 12 is similarly applied to the same portion with a cotton swab and dried. I let you.

(Example 7)
Aron T-50 (weight average molecular weight 6000) manufactured by Toagosei Co., Ltd. as 250 g / L of Snowtex C (solid content 20%) manufactured by Nissan Chemical Industries, Ltd., 100 g / L of monosodium phosphate, and sodium polyacrylate Was added to pure water so that the solid content was 100 g / L to obtain a desensitizing solution 13. After applying the above-described desensitizing solution 1 to a part of the image portion and non-image portion of the planographic printing plate with a cotton swab and drying, the above-described desensitizing solution 13 is similarly applied to the same portion with a cotton swab and dried. I let you.

<Printing evaluation>
The lithographic printing plate subjected to the image correction processing as described above was mounted on a printing machine (Sprint 226 printing machine manufactured by Komori Corporation), and lithographic printing was started. The ink used for printing was TK NEX Indigo LZ manufactured by Toyo Ink Co., Ltd., and the dampening solution used was SLM-OD50 manufactured by Mitsubishi Paper Industries Co., Ltd. diluted to 2% by mass. Printing was performed 1000 sheets, and the ink stains of the image area and the non-image area to which the desensitizing liquid was applied were visually observed on the printed matter.

The desensitization of the image area was evaluated according to the following criteria. The results are shown in Table 1.
○: The presence of the image portion cannot be visually recognized on the printed matter.
(Triangle | delta): It can visually recognize if presence of an image part looks good on printed matter.
X: The presence of the image portion can be clearly visually recognized on the printed matter.

Ink stains on non-image areas were evaluated according to the following criteria. The results are shown in Table 1.
○: Ink smear is not observed in the application part of the desensitizing liquid on the printed matter.
(Triangle | delta): Ink stain | pollution | contamination is recognized slightly in the application part of a desensitizing liquid on printed matter.
X: Ink smear is observed in the application part of the desensitizing liquid on the printed matter.

  As is clear from the above results, according to the present invention, it is possible to correct the printed image when lithographic printing is performed by desensitizing the unnecessary image portion of the photosensitive lithographic printing plate, and It is possible to provide a method for correcting an image of a photosensitive lithographic printing plate that does not cause ink smearing even when the desensitizing liquid adheres to a non-image area.

Claims (1)

  On the support, a hydrophilic layer containing 60% by mass or more of an inorganic filler and a hydrophilic binder with respect to the total solid content of the hydrophilic layer, and a compound having a polymerizable double bond group on the hydrophilic layer An image of a photosensitive lithographic printing plate characterized by adding polyethyleneimine, polyacrylic acid or a salt thereof, and inorganic fine particles to an unnecessary image portion after making a photosensitive lithographic printing plate having at least a photosensitive layer. How to fix.