JP2012145852A - Development processing method of photosensitive planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a development processing method of photosensitive planographic printing plate that improves development unevenness of a photosensitive planographic printing plate provided with a hydrophilic layer on a plastic film support, improves development unevenness even when a photosensitive layer capable of chemical-less processing is especially provided on the hydrophilic layer and achieves an excellent plate life.SOLUTION: In a development processing method of photosensitive planographic printing plate, with respect to a relationship between a conveyance speed P (mm/second) of photosensitive planographic printing plate and a rotating speed S (rpm) of scrub roller, a value of S/P is set within a range from 20 to 40.

Description

  The present invention relates to a development processing method for a photosensitive lithographic printing plate having at least a hydrophilic layer and a photosensitive layer on a plastic film support.

  Computer-to-plate (CTP) technology has been developed to output directly to the printing plate without outputting it on the film based on digital data produced on a computer, and various plate setters equipped with various lasers as output machines The development of photosensitive lithographic printing plates suitable for these has been actively conducted. When a plastic film support is used as a support for such a photosensitive lithographic printing plate, there is an advantage that it can be stored compactly in a plate setter. In addition, the printing system for the plastic film support is advantageous in that it can be supplied in rolls and is lighter and easier to handle than the printing plate on the aluminum support. However, important problems or demands that have been raised with the spread of the CTP method include various points related to development processing.

  In a photosensitive lithographic printing plate using a plastic film support, a hydrophilic layer is provided on the plastic film support, and the hydrophilic layer is exposed by development to impart ink resilience. Examples of such a hydrophilic layer include a hydrophilic resin layer made of a (meth) acrylate polymer having a hydroxyalkyl group described in JP-B-49-2286, and a urea resin described in JP-B-56-2938. A hydrophilic layer composed of a pigment, a hydrophilic layer obtained by curing an acrylamide polymer described in JP-A-48-83902 with aldehydes, and a water-soluble melamine described in JP-A-62-280766 A hydrophilic layer obtained by curing a composition containing a resin, polyvinyl alcohol and a water-insoluble inorganic powder, and a water-soluble polymer containing a repeating unit having an amidino group in the side chain described in JP-A-8-184967. Hydrolyzed layer obtained by curing, a hydrolyzed tet containing a hydrophilic (co) polymer described in JP-A-8-272087 A hydrophilic layer cured with an alkyl orthosilicate, a hydrophilic layer having an onium group described in JP-A-10-296895, and a crosslinked hydrophilic polymer having a Lewis base moiety described in JP-A-11-311861 Numerous hydrophilic layers such as a hydrophilic layer obtained by three-dimensional crosslinking by interaction with a valent metal ion, a hydrophilic layer described in JP 2000-122269 A, and a hydrophilic layer containing a water-dispersible filler. Sexual layers are known.

  On the other hand, lithographic printing plates using these CTP systems are subjected to image exposure processing by laser exposure and development processing. When performing development using an automatic developing machine, the printing plate is immersed in a developer filled in a developing tank, and the printing plate is conveyed at a contact portion of one to four brush rollers while being conveyed by a roll. In general, a developing process is performed in which a brush roller or a Molton roller is rotated so as to mix and rub the same direction or the opposite direction to the advancing direction to remove the photosensitive layer in the non-image area. Incidentally, when referring to either or both of the brush roller and the molton roller, they are also referred to as “scrubbing rollers” hereinafter.

  However, the image portion of a photosensitive lithographic printing plate having a hydrophilic layer on a plastic film support may have poorer adhesion than an image portion formed on a roughened and anodized aluminum support, Further, since the developing solution penetrates to some extent in the image area itself, the strength of the image area is likely to decrease due to swelling of the coating film. For this reason, if the photosensitive layer in the non-image area is removed with the scrub roller, the image area is liable to be peeled off or scratched, and adjustment such as reducing the contact pressure on the photosensitive surface of the scrub roller to prevent such an image area defect. This time, there is a problem that the remaining film removal of the non-image portion becomes insufficient and development unevenness is likely to occur.

  In recent years, from development systems using special chemicals normally used in conventional printing plates near digital equipment, development with water, or development with a chemical-less developer containing substantially no alkali agent, or these A photosensitive lithographic printing plate capable of on-press development (development on a printing press) using a lime is attracting attention. In the CTP system using these chemically-less photosensitive lithographic printing plates, a special developing chemical typified by strong alkali is not substantially used, so that no processing chemical cost is required or the waste liquid processing cost is low. At the same time, it has the benefit of reducing environmental impact.

  However, the photosensitive layer of the chemicalless photosensitive printing plate can be developed with water, or developed with a chemicalless developer containing substantially no alkali agent, so that the photosensitive layer is easily swollen by these developers. Designed (to be relatively hydrophilic). For this reason, when the photosensitive layer in the non-image area is removed with the scrub roller, the above-mentioned peeling or scratches of the image area appear remarkably, and adjusting the contact pressure of the scrub roller in order to eliminate the scratches can provide sufficient printing durability. There is a problem that it is more difficult to obtain, and improvement has been demanded.

  On the other hand, the relationship between the transport speed P (mm / second) of the photosensitive lithographic printing plate and the rotation speed S (rpm) of the scrub roller, and the value of S / P are in a very wide range for each lithographic printing plate. For example, Japanese Patent No. 2847398 (Patent Document 1) discloses that a photosensitive lithographic printing plate conveyance speed P (mm / second) and a scrub roller rotation speed S (rpm) It is suggested that the S / P value is 3.3 to 125, and that the waterless lithographic printing plate has an S / P value of 26.7 to 325. In JP 2009-175583 A (Patent Document 2), the value of S / P is set to 4 to 4 for the purpose of improving the stain and printing durability of a lithographic printing plate using a photosensitive layer containing an alkali-soluble resin. 25. Japanese Patent Application Laid-Open No. 2010-197620 (Patent Document 3) suggests that the value of S / P at the time of PS plate development is 5.3 to 53. Document 4) suggests that the S / P value is 52.4 to 261.8.

Japanese Patent No. 2847398 JP 2009-175583 A JP 2010-197620 A JP-A-8-054728

  Accordingly, an object of the present invention is to improve development unevenness of a photosensitive lithographic printing plate having at least a hydrophilic layer on a plastic film support, and in particular, to provide a photosensitive layer capable of chemicalless processing on the hydrophilic layer. Even in such a case, it is an object of the present invention to provide a method for developing a photosensitive lithographic printing plate in which uneven development is improved and excellent printing durability is obtained.

The above object of the present invention has been achieved by the following processing method.
1. A photosensitive lithographic printing plate having at least a hydrophilic layer on a plastic film support and at least a photosensitive layer on the hydrophilic layer is immersed in a developer, and the photosensitive lithographic printing plate on the side having the photosensitive layer is immersed. In the development processing method of a photosensitive lithographic printing plate in which the surface is rubbed with a scrub roller, the relationship between the conveying speed P (mm / second) of the photosensitive lithographic printing plate and the rotational speed S (rpm) of the scrub roller, and the value of S / P is A developing method for a photosensitive lithographic printing plate, characterized in that it is 20-40.

  By the development processing method of the photosensitive lithographic printing plate of the present invention, development unevenness of the photosensitive lithographic printing plate in which at least a hydrophilic layer is provided on a plastic film support is improved, and in particular, a chemicalless treatment is performed on the hydrophilic layer. Even when a possible photosensitive layer is provided, it is possible to provide a development processing method for a photosensitive lithographic printing plate in which development unevenness is improved and excellent printing durability can be obtained.

1 is a schematic view of a plate making apparatus using a photosensitive lithographic printing plate development processing method of the present invention. FIG.

  As a result of intensive studies, the present inventor has found that it is useful to increase the rotation speed of the scrub roller to a certain speed with respect to the conveyance speed of the photosensitive lithographic printing plate in order to solve the above problems.

  With respect to the development processing method of the photosensitive lithographic printing plate of the present invention, an example in which the development processing method of the present invention is applied to a chemicalless development processing will be given, and the embodiments according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of a plate making apparatus using the photosensitive lithographic printing plate development processing method of the present invention.

  In FIG. 1, the leading end portion of the photosensitive lithographic printing plate M on which an image is recorded by the exposure device 7 enters the photosensitive material processing device 9 through the introduction guide 10, and the developer is developed by the pair of introduction rollers 11 and 12. The photosensitive lithographic printing plate M is transported between the transport guide 30 and the guide roller 13 with the photosensitive layer surface facing up, and the nip roller pairs 31 and 32 in the developer tank 22 are moved between the transport guide 30 and the guide roller 13. After passing, the hydrophilic layer is exposed by passing through the roller pair of the scrub roller 33 and the backup roller 34 and rubbing the surface of the photosensitive lithographic printing plate M having the photosensitive layer. The developing process is performed by squeezing the developer. Subsequently, the photosensitive lithographic printing plate M is transported along the transfer guide 37 between the developing tank 22 and the rinsing tank 23, and is guided to the transport guide 19 in the rinsing tank 23 by the pair of introduction rollers 17 and 18. While the photosensitive layer surface and the back surface of the printing plate M are cleaned by sprays 14 and 15 that circulate and spray the rinsing liquid, excess rinsing liquid of the photosensitive lithographic printing plate M is drawn and rinsed by the pair of squeezing rollers 20 and 21. Done. Then, the photosensitive lithographic printing plate M after the rinsing process is conveyed to the drying unit 3, and has a fan 25 and a heater 26 to dry the photosensitive lithographic printing plate M by blowing warm air on the photosensitive lithographic printing plate M. Is discharged. As a typical example of the chemicalless development processing, water is used as a processing solution to be introduced into the developing tank 22 and the rinsing tank 23.

  Next, replenishment of water as a processing solution to the developing tank 22 and the rinsing tank 23 will be described with reference to FIG. The developing tank 22 is connected to a pump 41 that circulates water that has been injected and stored in advance so as to maintain the water at a predetermined temperature by the heater 24, and constantly circulates water. Further, a filter 40 is installed on the downstream side of the pump 41 in the circulation pipe. The rinse tank 23 is also circulated and supplied with pre-injected and stored water through sprays 14 and 15 at a normal temperature by a pump 42. The replenishing tank 47 stores water used as a developing solution or a rinsing solution, and a predetermined amount is supplied by the pump 43 and the pump 44 according to the plate making amount of the photosensitive lithographic printing plate M, and the developing tank 22 and the developing layer 22. To replenish. As such a pump, for example, a peristaltic pump, a bellows pump, a diaphragm pump, an oscillating pump, or the like can be used. The rinsing liquid exceeding the liquid level of the rinsing tank 23 flows into the developing tank from a notch on the tank wall surface (not shown), the liquid level of the developing tank is controlled, and the developing liquid exceeding the liquid level of the developing tank is overflow pipe 38. And stored in the waste liquid tank 46.

  In the present invention, as the scrub roller 33 provided in the developing tank, a Molton roller or a rotary brush roller is preferably used. In the plate-making apparatus of FIG. 1, while developing solution is circulated, the scrub roller is brought into contact with the surface having the photosensitive layer to scrape off the unnecessary photosensitive layer and the like to carry out the development processing. Molton roller is made of nitrile rubber, ethylene-propylene copolymer rubber, polyurethane or other rubber roller or ABS, polyurethane or other resin roller with a material consisting mainly of 2-5mm thick cotton as a scrub member. The fiber is preferably used, and the fiber is generally about 5 to 15 μm in thickness and about 1 to 3 mm in length.

  It is preferable that the fiber layer is formed as homogeneously as possible on the surface of the Molton roller, and it is preferable that the surface on the side having the photosensitive layer is rubbed uniformly by taking a method such as suppressing fuzz. Furthermore, as the drive roller, the Morton roller effectively removes the remaining film on the non-image area by rotating in the same direction as the transport direction or in the opposite direction without synchronizing with the transport speed of the transported plate material. It is preferably done. More preferably, the Molton roller is rotated in the same direction as the conveying direction.

  Regarding the brush roller as another preferred example of the scrub roller 33 provided in the developing tank in the present invention, a brush roller using a brush wire material such as nylon or polypropylene is preferable, and an implantation roller brush and a channel roller brush are preferably used. Is done. Also in this case, the brush roller is preferably a driving roller driven by an original driving device, and is preferably rotated in the same direction or in the opposite direction with respect to the conveying direction of the plate material and rubs the surface.

  The disposition position of the scrub roller 33 is preferably in the range of 2/3 to 9/10 from the entrance side in the process in which the photosensitive lithographic printing plate is immersed in the developer. Before this, the image portion may be scratched, and it is physically difficult and apparatus-wise to dispose the immersed scrub roller on the exit side beyond this range.

  The diameter of the scrub roller 33 is set to about 25 to 60 mm, preferably 35 to 55 mm. The rotational speed S of the scrub roller 33 is preferably 100 to 200 rpm, more preferably 130 to 180 rpm. If the speed is slower than this, the photosensitive layer may remain in a horizontal shape, and if the speed is too high, the density of the image area and the printing durability may be lowered.

  The contact pressure between the scrub roller 33 and the photosensitive lithographic printing plate M is preferably in the range of 0.15 to 0.80 kg / 10 cm. More preferably, it is the range of 0.25-0.6 kg / 10cm. The contact pressure can be measured with a digital force gauge when a photosensitive lithographic printing plate having a width of 10 cm passes through a scrub roller (using FGP-10 manufactured by Nidec Sympo Co., Ltd.). If the pressure is lower than this, the photosensitive layer may remain. If the pressure is too high, the density of the image area and the printing durability may be reduced. The conveyance speed P of the photosensitive lithographic printing plate is preferably 8 to 15 (mm / second), and the conveyance speed P (mm / second) of the photosensitive lithographic printing plate and the rotation speed S (rpm) of the scrub roller. More preferably, the value of the relationship, S / P, is 26-39.

  As the hydrophilic layer of the photosensitive lithographic printing plate of the present invention, a conventionally known layer can be used. For example, the (meth) acrylate polymer having a hydroxyalkyl group described in JP-B No. 49-2286 described above. Obtained by curing with aldehydes a hydrophilic layer composed of a urea resin and a pigment described in JP-B-56-2938, and an acrylamide polymer described in JP-A-48-83902. A hydrophilic layer obtained by curing a composition containing a water-soluble melamine resin, polyvinyl alcohol, and a water-insoluble inorganic powder described in JP-A-62-280766, JP-A-8-184967 A hydrophilic layer obtained by curing a water-soluble polymer containing a repeating unit having an amidino group in the side chain described in the publication, JP-A-8-272087 A hydrophilic layer containing a hydrophilic (co) polymer described in the publication and cured with hydrolyzed tetraalkylorthosilicate, a hydrophilic layer having an onium group described in JP-A-10-296895, A hydrophilic layer obtained by three-dimensionally cross-linking a crosslinked hydrophilic polymer having a Lewis base moiety described in JP-A-11-311861 by interaction with a polyvalent metal ion, and a hydrophilic layer described in JP-A-2000-122269 Examples include a hydrophilic layer containing a resin and a water-dispersible filler.

  The hydrophilic layer of the present invention particularly preferably contains a polymer represented by the following general formula (1) from the viewpoint of obtaining excellent printing durability and stain resistance.

  In the formula, X represents mass% of repeating units in the polymer composition, and represents an arbitrary numerical value from 1 to 40. The repeating unit A represents a repeating unit having a group selected from a carboxy group, an amino group, a hydroxyl group and an acetoacetoxy group as a reactive group, and the repeating unit B is a repeating unit having a hydrophilic group necessary for making the polymer water-soluble. Represents a unit.

  It is important that the water-soluble polymer represented by the general formula (1) contains a reactive group in the molecule for allowing a crosslinking reaction to proceed efficiently with a crosslinking agent described later. Examples of such reactive groups include a carboxy group, an amino group, a hydroxyl group, and an acetoacetoxy group. In order to obtain a water-soluble polymer having such a reactive group in the molecule, it is preferable to incorporate various monomers having a reactive group in a copolymerized form. As the monomer corresponding to the repeating unit A represented by the general formula (1), acrylic acid, methacrylic acid, 2-carboxyethyl acrylate, 2-carboxyethyl methacrylate, itaconic acid, crotonic acid, maleic acid, fumaric acid, cinnamic acid Carboxy group-containing monomers such as maleic acid monoalkyl ester, fumaric acid monoalkyl ester, 4-carboxystyrene, acrylamide-N-glycolic acid and their salts, allylamine, diallylamine, 2-dimethylaminoethyl acrylate, 2-dimethylamino Ethyl methacrylate, 2-diethylaminoethyl acrylate, 2-diethylaminoethyl methacrylate, 3-dimethylaminopropyl acrylamide, 3-dimethylaminopropyl methacrylamide, 4-aminostyrene Amino group-containing monomers such as 4-aminomethylstyrene, N, N-dimethyl-N- (4-vinylbenzyl) amine, N, N-diethyl-N- (4-vinylbenzyl) amine, 4-vinylpyridine, 2 Nitrogen-containing heterocycle-containing monomers such as vinylpyridine and N-vinylimidazole, (meth) acrylamides such as N-methylolacrylamide and 4-hydroxyphenylacrylamide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxy Examples thereof include hydroxyalkyl (meth) acrylates such as propyl acrylate, 2-hydroxypropyl methacrylate, and glycerol monomethacrylate, and acetoacetoxy methacrylate, but are not limited to these examples.

  In the general formula (1), X, which is the ratio of the repeating unit A in the copolymer, is 1 to 40, and if it is less than this range, sufficient film strength may not be obtained even if the crosslinking reaction proceeds. If it is more than this range, the effect of introducing the repeating unit B for imparting water solubility described below is lessened, and the affinity of the hydrophilic layer for water may be lowered.

  Furthermore, as a monomer for giving the repeating unit B in the general formula (1), vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, styrene sulfonic acid, 2-sulfoethyl methacrylate, 3-sulfopropyl methacrylate, 2- Sulfonic acid group-containing monomers such as acrylamido-2-methylpropanesulfonic acid and their salts, Phosphoric acid group-containing monomers such as vinylphosphonic acid and their salts, dimethyl diallyl ammonium chloride, acrylic acid-2- (trimethylammonio) Ethyl ester, methacrylic acid-2- (trimethylammonio) ethyl ester, acrylic acid-2- (triethylammonio) ethyl ester, methacrylic acid-2- (triethylammonio) ethyl ester, (3-acrylamidopropyl) trime Quaternary ammonium salts such as ruammonium chloride, N, N, N-trimethyl-N- (4-vinylbenzyl) ammonium chloride, acrylamide, methacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N (Meth) acrylamides such as N, diethylacrylamide, N-isopropylmethacrylamide, methacrylic acid methoxydiethylene glycol monoester, methacrylic acid methoxypolyethylene glycol monoester, methacrylic acid polypropylene glycol monoester , N-vinyl pyrrolidone, N-vinyl caprolactam and the like, but are not limited thereto. These water-soluble monomers may be used alone to constitute the repeating unit B, or any two or more of them may be used. Specific examples of preferable water-soluble polymers in the present invention are shown below. In the present invention, water-soluble means that 0.5 g or more of a water-soluble polymer is dissolved in 1 L of water.

  The hydrophilic layer of the photosensitive lithographic printing plate of the present invention preferably contains inorganic fine particles. Examples of these inorganic fine particles include colloidal silica, titanium dioxide particles, alumina particles (for example, aluminum oxide hydrate, aluminum hydroxide), zeolite, and other metal oxide particles. These inorganic fine particles may be subjected to surface treatment on the particle surface. Preferred inorganic fine particles of the present invention include colloidal silica and titanium dioxide particles, and colloidal silica is particularly preferred.

  The colloidal silica preferably used in the present invention is a sphere, needle shape, irregular shape, or a necklace shape in which spherical particles are connected, preferably having an average particle diameter of 5 to 200 nm measured by a light scattering particle size distribution analyzer. Silica sols having various shapes and particle diameters and stably dispersed in water are preferably used. As such materials, various colloidal silicas are provided, for example, under the name of Snowtex from Nissan Chemical Industries, Ltd., and as a spherical silica sol, Snowtex XS (particle diameter 4 to 6 nm), Snowtex S (particle diameter 8) To 11 nm), Snowtex 20 (particle size 10 to 20 nm), Snowtex XL (particle size 40 to 60 nm), Snowtex YL (particle size 50 to 80 nm), Snowtex ZL (particle size 70 to 100 nm), Snowtex As an acidic type silica sol from which MP-2040 (particle diameter: 200 nm) and sodium salt on the surface have been removed, Snowtex OXS, OS and the like can be preferably used. Examples of the needle-like or amorphous silica sol include Snowtex UP, OUP, and Fine Cataloid F-120 from JGC Catalysts & Chemicals. Examples of the necklace-shaped silica sol include Snowtex PS-S (particle diameter 80 to 120 nm), PS-M (particle diameter 80 to 150 nm), and PS-SO and PS-MO which are acidic types thereof.

  The titanium dioxide particles preferably used in the present invention are preferably spherical particles having an average particle diameter of 10 to 800 nm, and the production method includes a chlorine method and a sulfuric acid method, such as anatase type, rutile type and bulcalite type. However, preferably, rutile type titanium dioxide is surface-treated with an inorganic substance. Inorganic treatment on the surface of titanium dioxide includes alumina treatment, silica treatment, zirconia treatment, zinc treatment, tin treatment, antimony treatment, and the like, and each oxide is used. Among these, silica treatment, zirconia treatment, and zinc treatment are preferable, and silica treatment and zirconia treatment are particularly preferable. These inorganic treatments may be a composite treatment, and examples thereof include a composite treatment of silica and alumina, a composite treatment of zirconia and alumina, and a composite treatment of silica, zirconia and alumina. Such titanium dioxide particles are, for example, from Sakai Chemical Industry Co., Ltd. R-11P (particle diameter 200 nm), R-21 (particle diameter 200 nm), R-61N (particle diameter 260 nm), R-5N (particle diameter 250 nm). ), R-45M (particle diameter 290 nm), A-110 (particle diameter 150 nm), A-190 (particle diameter 150 nm) from Ishihara Sangyo Co., Ltd. TTO-55A (particle diameter 30-50 nm), TTO-55D ( The particle diameter is 30-50 nm).

  As the inorganic fine particles contained in the hydrophilic layer, each kind of inorganic fine particles may be used alone, or different kinds of inorganic fine particles may be mixed and used in various proportions. The content of the inorganic fine particles as described above is preferably in the range of 0.1 to 10 parts by mass, particularly preferably in the range of 0.5 to 5 parts by mass with respect to 1 part by mass of the water-soluble polymer.

  There is a preferred range for the dry weight of the hydrophilic layer, specifically, the dry weight of the hydrophilic layer is between 0.1 g and 10 g per square meter, and the preferred range is 0.2 g to 5 g per square meter. The most preferred range is between 0.3 g and 2 g per square meter.

  The hydrophilic layer of the present invention preferably contains a crosslinking agent, and examples of such a crosslinking agent include various known compounds. Specific examples include epoxy compounds, aziridine compounds, oxazoline compounds, isocyanate compounds and derivatives thereof, aldehyde compounds such as formalin, methylol compounds, hydrazide compounds, and the like. Particularly preferred crosslinking agents are epoxy compounds.

  As the epoxy compound, a compound having two or more epoxy groups in the molecule is preferably used. Specific examples of preferred epoxy compounds are shown below.

  Specific examples of preferable compounds as the aziridine compound are shown below.

  As the oxazoline compound, a compound containing two or more groups represented by the following general formula (2) in the molecule as a substituent is preferable, and various commercially available compounds are provided, for example, by Nippon Shokubai Co., Ltd. under the trade name Epocross. Various grades of compounds are preferably used.

  As the isocyanate compound, a compound that is stable in water is preferable, and a so-called self-emulsifiable isocyanate compound or a blocked isocyanate compound is preferably used. Examples of self-emulsifying isocyanate compounds include Japanese Patent Publication No. 55-7472 (US Pat. No. 3,996,154) and Japanese Patent Laid-Open No. 5-222150 (US Pat. No. 5,252,696). Self-emulsifiable isocyanate as described in JP-A-9-71720, JP-A-9-328654, JP-A-10-60073, and the like.

  Examples of aldehyde compounds and methylol compounds such as formaldehyde and glyoxal include formaldehyde, glyoxal, and various N-methylol compounds as shown below.

  Specific examples of compounds that can be preferably used as the hydrazide compound are shown below.

  The hydrophilic layer of the present invention can contain a surfactant, a pH adjuster and the like in addition to the water-soluble polymer, inorganic fine particles, and crosslinking agent described above.

  Although the photosensitive lithographic printing plate of the present invention has at least a hydrophilic layer and a photosensitive layer, an intermediate layer may be provided between the plastic film support and the hydrophilic layer. Such an intermediate layer can contain inorganic porous compounds, gelatin or polyacrylic acids, crosslinking agents, polymers, latexes, surfactants, pH adjusting agents, etc., and 0.5 g per square meter in terms of dry mass. To between 50 and 50 g.

  The photosensitive layer of the photosensitive lithographic printing plate used in the present invention may be either a positive type or a negative type. Examples of the positive photosensitive layer include a photosensitive layer containing a substance that can be decomposed by an acid. Examples of such a photosensitive layer include light that generates an acid by laser exposure described in JP-A-9-171254. Phenol such as a cresol novolac resin described in WO 97/39894, a photosensitive layer composed of an acid-decomposing compound and an infrared absorber that are decomposed by an acid generator and the generated acid to increase solubility in a developer. And an aqueous alkali-soluble resin having a functional hydroxyl group and (B) a photosensitive layer containing an infrared absorber.

  As the negative photosensitive layer, for example, a photosensitive layer using a photocurable photosensitive composition using a diazo resin, a cinnamic acid derivative resin, an azide compound or the like, a photosensitive layer using a high-sensitivity photopolymer system, Examples of a system utilizing an output (near) infrared laser include a photosensitive layer composed of a near-infrared absorbing dye, a novolak resin, a resole resin, and a photoacid generator as described in JP-A-7-271029. It is done.

  Among these photosensitive layers, especially when using high-sensitivity photopolymer systems or near-infrared photosensitive systems, the photosensitive layer may be relatively soft. However, the development processing method according to the present invention can be particularly preferably used since such damage to the image area can be effectively prevented.

  High-sensitivity photopolymer-based photosensitive layers include a monomer having a phenyl group substituted with a vinyl group as a monomer having a polymerizable double bond, and a monomer having a carboxy group in the structure as a water-soluble group-containing monomer (for example, acrylic acid). , Methacrylic acid, 4-carboxystyrene, carboxyethyl acrylate, etc.) as a copolymerization component, and a copolymer having a phenyl group and a carboxy group substituted with a vinyl group in the side chain (hereinafter referred to as a carboxylic acid type polymer). Can be mentioned. The phenyl group having a vinyl group substituted on the side chain of the copolymer is specifically represented by the following general formula (3).

In the formula, R ₁₁ , R ₁₂ and R ₁₃ may be the same or different and are each a hydrogen atom, halogen atom, carboxy group, sulfo group, nitro group, cyano group, amide group, amino group, alkyl group. A group selected from a group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylamino group, an arylamino group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, and an arylsulfonyl group The alkyl group and aryl group constituting these groups are a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, an aryl group, an alkenyl group, a hydroxy group, and an alkoxy group. , Aryloxy group, alkylthio group, arylthio group, alkyl It may be substituted with an amino group, arylamino group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group or the like. Among these groups, those in which R ₁₁ is a hydrogen atom or a lower alkyl group having 4 or less carbon atoms (for example, a methyl group, an ethyl group, etc.) and R ₁₂ and R ₁₃ are hydrogen atoms are particularly preferable.

In the formula, R ₁₄ represents a hydrogen atom, a halogen atom, a carboxy group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylamino group, A group selected from an arylamino group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, and an arylsulfonyl group. The alkyl group and aryl group constituting these groups are halogen atom, carboxy group, sulfo group, nitro group, cyano group, amide group, amino group, alkyl group, aryl group, alkenyl group, alkynyl group, hydroxy group. , An alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylamino group, an arylamino group, an acyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, an arylsulfonyl group and the like.

In the formula, m ₁ represents an integer of 0 to 4, and p ₁ represents an integer of 0 or 1. L ₁ represents an atom selected from a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom or a polyvalent linking group comprising a hydrogen atom, a carbon atom, a nitrogen atom, an oxygen atom and a sulfur atom group.

Examples of the heterocyclic ring constituting L ₁ include pyrrole ring, pyrazole ring, imidazole ring, triazole ring, tetrazole ring, isoxazole ring, oxazole ring, oxadiazole ring, isothiazole ring, thiazole ring, thiadiazole ring, thia Triazole ring, indole ring, indazole ring, benzimidazole ring, benzotriazole ring, benzoxazole ring, benzthiazole ring, benzselenazole ring, benzothiadiazole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, quinoline And a nitrogen-containing heterocycle such as a ring and a quinoxaline ring, a furan ring, a thiophene ring, and the like. These heterocycles may have a substituent.

  When the polyvalent linking group described above has a substituent, examples of the substituent include a halogen atom, a carboxy group, a sulfo group, a nitro group, a cyano group, an amide group, an amino group, an alkyl group, an aryl group, an alkenyl group, and an alkynyl group. Group, hydroxy group, alkoxy group, aryloxy group, alkylthio group, arylthio group, alkylamino group, arylamino group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, alkylsulfonyl group, arylsulfonyl group and the like.

  Specific examples of the carboxylic acid type polymer in the present invention are shown below.

  In addition, as described above, a photosensitive lithographic printing plate provided with a photosensitive layer that can be developed with a chemicalless developer containing substantially no alkali agent, or on-press development using these (on-press development). In this case, peeling and scratches in the image area appear particularly prominent, and it is extremely difficult to obtain sufficient printing durability if the contact pressure of the scrub roller is adjusted to eliminate the scratches. It works particularly effectively in such systems. Hereinafter, the photosensitive layer which enables development with a chemicalless developer substantially free of an alkali agent or on-press development will be described.

  A photosensitive layer that can be developed with a chemical-less developer or on-press development is described in, for example, Japanese Patent Application Laid-Open No. 2003-215801. The photosensitive layer includes a monomer having a phenyl group substituted with a vinyl group and a water-soluble layer. Monomers having a sulfonic acid group in the structure (for example, 3-sulfopropyl methacrylate, 4-sulfostyrene, 4-sulfo-n-butylmethacrylamide, sulfo-tert-butylacrylamide, etc.) An anionic copolymer having a phenyl group substituted with a vinyl group in the side chain and a sulfonic acid group (hereinafter referred to as a sulfonic acid type polymer) is included as a polymerization component, and the sulfonic acid group is a salt (for example, sodium Salt, potassium salt, triethylammonium salt, lithium salt, tetramethylammonium salt, etc.) It may form. In this sulfonic acid type polymer, an alkaline developer containing an alkaline agent may be used because the sulfonic acid group in the structure increases water solubility, but the pH value of the developer which is a more preferred embodiment of the present invention is 10 A method using a chemical-less developer in the range of less than 0.0 is possible. Further, by having a phenyl group substituted with a vinyl group in the side chain, high sensitivity can be achieved.

  Specific examples of the sulfonic acid type polymer in the present invention are shown below.

  The photosensitive layer of the photosensitive lithographic printing plate of the present invention preferably contains a photopolymerization initiator. As such a photopolymerization initiator, any compound can be used as long as it is a compound capable of generating radicals upon irradiation with light or an electron beam. The following photopolymerization initiators are also preferably used in the above-described high-sensitivity photopolymer-based photosensitive layer.

  Examples of the photopolymerization initiator that can be used in the present invention include (a) an organic boron salt compound, (b) an aromatic onium salt compound, (c) an organic peroxide, (d) a hexaarylbiimidazole compound, ( e) ketoxime ester compounds, (f) azinium salt compounds, (g) active ester compounds, (h) metallocene compounds, (i) trihaloalkyl-substituted compounds, (j) aromatic ketones, etc. The polymerization initiator is (a) an organic boron salt compound and (i) a trihaloalkyl-substituted compound.

  Examples of (a) organic boron salt compounds include JP-A-8-217813, JP-A-9-106242, JP-A-9-188585, JP-A-9-188686, and JP-A-9-188710. Organoboron ammonium compounds described in JP-A-6-175561, JP-A-6-175564, JP-A-6-157623, and the like. Organoboron iodonium compounds described in JP-A-6-175553, JP-A-6-175554, etc., Organoboron phosphonium compounds described in JP-A-9-188710, JP-A-6-348011, JP-A-7- 128785, JP-A-7-140589, JP-A-7-2920 4 JP, organic boron transition metal coordination complex compound described in JP-A-7-306527 Patent Publication, and the like. Examples of the counter anion described in JP-A-62-143044 and JP-A-5-194619 include cationic dyes containing an organic boron anion.

  (B) Examples of aromatic onium salt compounds include N, P, As, Sb, Bi, O, S, Se, Te, or I aromatic onium salts. Examples of such aromatic onium salt compounds include compounds exemplified in Japanese Patent Publication No. 52-14277, Japanese Patent Publication No. 52-14278, Japanese Patent Publication No. 52-14279, and the like.

  (C) Examples of the organic peroxide include almost all organic compounds having one or more oxygen-oxygen bonds in the molecule. For example, 3,3 ′, 4,4′-tetra (tert-butyl) Peroxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (tert-amylperoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetra (tert-hexylperoxycarbonyl) benzophenone, 3, 3 ', 4,4'-tetra (tert-octylperoxycarbonyl) benzophenone, 3,3', 4,4'-tetra (cumylperoxycarbonyl) benzophenone, 3,3 ', 4,4'-tetra ( p-Isopropylcumylperoxycarbonyl) benzophenone, di (tert-butyldiperoxy) isophthalate, etc. Le systems are preferred.

  (D) Examples of hexaarylbiimidazole compounds include lophine dimers described in JP-B-45-37377 and JP-B-44-86516, such as 2,2′-bis (o-chlorophenyl) -4, 4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-bromophenyl) -4,4', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o, p-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-chlorophenyl) -4,4', 5,5'-tetra (m-methoxyphenyl) bi Imidazole, 2,2'-bis (o, o'-dichlorophenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-nitrophenyl) -4,4', 5 5'-tetraphenylbiimidazole, 2,2'-bis (o-methylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole, 2,2'-bis (o-trifluoromethylphenyl) -4,4 ', 5,5'-tetraphenylbiimidazole and the like.

  (E) Examples of ketoxime ester compounds include 3-benzoyloxyiminobutan-2-one, 3-acetoxyiminobutan-2-one, 3-propionyloxyiminobutan-2-one, 2-acetoxyiminopentane -3-one, 2-acetoxyimino-1-phenylpropan-1-one, 2-benzoyloxyimino-1-phenylpropan-1-one, 3- (p-toluenesulfonyloxyimino) butan-2-one , 2-ethoxycarbonyloxyimino-1-phenylpropan-1-one and the like.

  Examples of (f) azinium salt compounds include JP-A-63-138345, JP-A-63-142345, JP-A-63-142346, JP-A-63-143537, JP-B-46. The compound group which has NO bond as described in -42363 gazette etc. can be mentioned.

  (G) Examples of active ester compounds include imide sulfonate compounds described in JP-B-62-2223 and the like, and active sulfonates described in JP-B-63-14340, JP-A-59-174831, and the like. Can be mentioned.

  (H) Examples of metallocene compounds include JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, and JP-A-2-4705. And titanocene compounds described in JP-A-1-304453, and iron-arene complexes described in JP-A-1-152109 and the like.

  (I) Specific examples of the trihaloalkyl-substituted compound include compounds having at least one trihaloalkyl group such as a trichloromethyl group and a tribromomethyl group in the molecule. US Pat. No. 3,954,475 Specification, U.S. Pat. No. 3,987,037, U.S. Pat. No. 4,189,323, JP-A-61-151644, JP-A-63-298339, JP-A-4-69661 And trihalomethyl-s-triazine compounds described in JP-A-11-153859, JP-A-54-74728, JP-A-55-77742, JP-A-60-138539, 2-Trihalomethyl-1,3 described in JP-A-61-143748, JP-A-4-362644, JP-A-11-84649, etc. 4- oxadiazole derivatives. Moreover, the trihaloalkylsulfonyl compound as described in Unexamined-Japanese-Patent No. 2001-290271 etc. which this trihaloalkyl group couple | bonded with the aromatic ring or the nitrogen-containing heterocyclic ring through the sulfonyl group is mentioned.

  (J) Preferred examples of aromatic ketones include “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY”. P. FUOASSIER, J.A. F. RABEK (1993), P.A. 77-P. 177, a compound having a benzophenone skeleton or a thioxanthone skeleton, an α-thiobenzophenone compound described in Japanese Patent Publication No. 47-6416, a benzoin ether compound described in Japanese Patent Publication No. 47-3981, and Japanese Patent Publication No. 47-22326 Α-substituted benzoin compounds described in JP-A No. 47-23664, benzoin derivatives described in JP-B-47-23664, aroylphosphonic acid esters described in JP-A-57-30704, and JP-B-60-26483 Dialkoxybenzophenones, benzoin ethers described in JP-B-60-26403, JP-A-62-181345, p-di (dimethylaminobenzoyl) benzene described in JP-A-2-211452, A thio-substituted aromatic keto described in JP 61-194062 A , Acylphosphine sulfides described in JP-B-2-9597, acylphosphines described in JP-B-2-9596, thioxanthones described in JP-B-63-61950, JP-B-59-42864 Can be mentioned.

  The photopolymerization initiator used in the present invention includes compounds known as photoacid generators. As the photoacid generator, any compound can be used as long as it is a compound that can be decomposed by irradiation with light or electron beam to generate a strong acid such as hydrochloric acid or sulfonic acid or an acid such as Lewis acid. Examples of photoacid generators that can be used in the present invention include (k) aromatic diazonium salt compounds, (l) p-valic acid-o-nitrobenzyl ester, benzenesulfonic acid-o-nitrobenzyl ester, o- Sulfonic acid ester derivatives such as nitrobenzyl esters, (m) 9,10-dimethoxyanthracene-2-sulfonic acid-4-nitrobenzyl ester, pyrogallol trismethanesulfonate, naphthoquinonediazide-4-sulfonic acid esters, (n) Sulfones such as dibenzylsulfone and 4-chlorophenyl-4'-methoxyphenyldisulfone, (o) phosphate ester derivatives and (p) U.S. Pat. No. 3,332,936, JP-A-2-83638, JP 11-322707 A, JP 2000-1469 A, etc. And the like sulfonyl diazomethane compounds described.

  The organic boron salt compound which is a particularly preferable photopolymerization initiator in the present invention is composed of an organic boron salt, and the organic boron anion constituting the organic boron salt is represented by the following general formula (4).

In the formula, each of R ₂₁ , R ₂₂ , R ₂₃ and R ₂₄ may be the same or different, and represents an alkyl group, an aryl group, an aralkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, or a heterocyclic group. To express. Of these, it is particularly preferred that one of R ₂₁ , R ₂₂ , R ₂₃ and R ₂₄ is an alkyl group and the other substituent is an aryl group.

  In the above-mentioned organoboron anion, a cation that forms a salt is simultaneously present. Examples of the cation in this case include alkali metal ions, onium ions, and cationic sensitizing dyes. Examples of onium salts include ammonium, sulfonium, iodonium and phosphonium compounds. When a salt of an alkali metal ion or onium compound and an organic boron anion is used, photosensitivity in the wavelength range of light absorbed by the dye is imparted by adding a sensitizing dye separately. When an organic boron anion is contained as a counter anion of the cationic sensitizing dye, photosensitivity is imparted according to the absorption wavelength of the sensitizing dye. However, in the latter case, it is preferable to further contain an organic boron anion as a counter anion of the alkali metal or onium salt.

  The organic boron salt used in the present invention is a salt containing the organic boron anion represented by the general formula (4) shown above, and alkali metal ions and onium compounds are preferably used as cations forming the salt. The Particularly preferable examples of the onium salt with an organic boron anion include ammonium salts such as tetraalkylammonium salts, sulfonium salts such as triarylsulfonium salts, and phosphonium salts such as triarylalkylphosphonium salts. Specific examples of particularly preferred organic boron salts are shown below.

  In the present invention, a trihaloalkyl-substituted compound can be used as a photopolymerization initiator that can be used with an organic boron salt to realize higher sensitivity and higher contrast. Specifically, the trihaloalkyl-substituted compound is a compound having at least one trihaloalkyl group such as a trichloromethyl group or a tribromomethyl group in the molecule. As a preferable example, the trihaloalkyl group is a nitrogen-containing complex. Examples of the compound bonded to the ring group include s-triazine derivatives and oxadiazole derivatives, or trihaloalkylsulfonyl compounds in which the trihaloalkyl group is bonded to an aromatic ring or a nitrogen-containing heterocycle via a sulfonyl group. .

  Particularly preferred specific examples of trihaloalkyl-substituted nitrogen-containing heterocyclic compounds and trihaloalkylsulfonyl compounds are shown below.

  The above photopolymerization initiators may be used alone or in any combination of two or more. The content of the photopolymerization initiator is preferably in the range of 1 to 100 parts by mass, more preferably in the range of 1 to 40 parts by mass with respect to 100 parts by mass of the polymer containing a monomer having a polymerizable double bond as a copolymerization component. Particularly preferred.

  The photosensitive layer of the photosensitive lithographic printing plate of the present invention preferably contains a sensitizing dye. Such a sensitizing dye sensitizes the aforementioned photopolymerization initiator to the absorption maximum wavelength of the sensitizing dye. This makes it possible to cope with exposure by various lasers (for example, a blue-violet semiconductor laser and a near infrared laser). And when the said photoinitiator is an organic boron salt, it has the characteristic that the sensitivity with respect to various laser beams becomes very high by combining with this sensitizing dye. The sensitizing dye specifically sensitizes the decomposition of the photopolymerization initiator in a wavelength range of 380 to 1300 nm, and includes various cationic dyes, anionic dyes, and merocyanine as neutral dyes having no charge. , Coumarin, xanthene, thioxanthene, azo dyes and the like can be used. Specific examples of the sensitizing dye according to the present invention are shown below.

  As the sensitizing dye of the present invention, a system that imparts sensitivity to light in the wavelength region of 750 to 1100 nm is preferable for near infrared laser, and the sensitizing dye needs to have absorption in such a wavelength region. There is a particularly preferred specific example used for such purposes.

  Specific examples of preferred sensitizing dyes used for blue-violet semiconductor lasers (violet lasers) having a light source at a short wavelength are shown below as sensitizing dyes of the present invention.

  The sensitizing dyes may be used alone or in any combination of two or more. The content of the sensitizing dye is preferably in the range of 0.1 to 50 parts by mass, more preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymer containing a monomer having a polymerizable double bond as a copolymerization component. The range of is particularly preferable.

  Addition of a colorant can be preferably performed as another element constituting the photosensitive layer. As a colorant, it is used for the purpose of enhancing the visibility of the image area after exposure and development processing, and various kinds of carbon black, phthalocyanine dye, triarylmethane dye, anthraquinone dye, azo dye, etc. Dyes and pigments can be used.

  About the element which comprises a photosensitive layer, other elements can also be contained in addition to the above-mentioned element for various purposes. For example, inorganic fine particles or organic fine particles are also preferably added for the purpose of preventing blocking of the photosensitive layer composition.

  There is a preferred range for the dry weight of the photosensitive layer, preferably a dry weight in the range of 0.2 to 5 grams per square meter, most preferred range of 0.5 to 3 grams per square meter.

  In the present invention, the photosensitive lithographic printing plate can increase the sensitivity of the photosensitive layer by providing an over layer on the photosensitive layer. As the overlayer used for this purpose, a water-soluble polymer material that blocks oxygen is preferable, and polyvinyl alcohol is preferably used. The polyvinyl alcohol used for the over layer may be partially substituted with an ester, an ether and an acetal as long as it contains a substantial amount of unsubstituted vinyl alcohol units necessary for the development of the required water solubility. Similarly, a part may contain other copolymer components. Specific examples of polyvinyl alcohol include those in which 71 to 100% by mass are hydrolyzed and the degree of polymerization is in the range of 300 to 2400. Specifically, PVA-105, PVA-110, and PVA manufactured by Kuraray Co., Ltd. -117, PVA-117H, PVA-120, PVA-124, PVA-124H, PVA-CS, PVA-CST, PVA-HC, PVA-203, PVA-204, PVA-205, PVA-210, PVA-217 , PVA-220, PVA-224, PVA-217EE, PVA-217E, PVA-220E, PVA-405, PVA-420, PVA-613 and the like. Examples of the copolymer include polyvinyl acetate chloroacetate or polyvinyl acetate chloropropionate, polyvinyl formal, polyvinyl acetal, and copolymers thereof that have been hydrolyzed by 88 to 100% by mass. Of these polyvinyl alcohols, the completely saponified type is particularly preferred.

  As an overlayer of the photosensitive lithographic printing plate, in addition to the above-mentioned polymer, the photosensitive layer has good film-forming properties so as to prevent contact with air as much as possible, especially contact with oxygen. A water-soluble polymer that can be removed may be used in combination. Specific examples of such water-soluble polymers include water-soluble acrylic resins, polyvinyl pyrrolidone, gelatin, gum arabic and the like. A surfactant may be added for the purpose of improving the coating property for coating on the photosensitive layer.

  The dry mass of the overlayer is preferably 0.1 to 10 g, more preferably 0.5 to 5 g per square meter.

  Examples of the plastic film support used as the support for the photosensitive lithographic printing plate of the present invention include polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polystyrene, polyvinyl acetal, polycarbonate, cellulose diacetate, cellulose triacetate, and propion. Examples include acid cellulose, cellulose butyrate, and cellulose nitrate. The surface of these plastic film supports is subjected to various hydrophilization treatments for the purpose of improving the adhesiveness with the hydrophilic layer or the intermediate layer and imparting water retention to the non-image area. Such hydrophilic treatment includes chemical treatment, discharge treatment, glow discharge treatment, flame treatment, ultraviolet treatment, high-frequency treatment, active plasma treatment, laser treatment, and other surface treatments, and a hydrophilic subbing layer is applied to the surface. These methods may be combined and implemented.

Next, the developer used in the development processing method of the present invention will be described.
Examples of the developer used in the present invention include a strong alkali developer that contains a large amount of an alkali agent that has been generally used, and a chemicalless developer that does not substantially contain an alkali agent.

  Unlike a strong alkali developer (usually exceeding pH 10) that contains a large amount of an alkali agent that has been generally used in the past, a chemicalless developer does not substantially contain an alkali agent. Call. Therefore, the pH of the chemical-less developer used in the development processing method of the present invention is less than 10, preferably less than 9.5, more preferably less than 8. The lower limit of pH is about 3. In the chemical-less developer used in the development processing method of the present invention, water accounts for 70% by mass or more, further 80% by mass or more of the entire developer, and other additives include ethanol, isopropanol, n- Various organic solvents such as Butyl Cellosolve, Ethylene Glycol, Diethylene Glycol, Triethylene Glycol, Glycerin, and Benzyl Alcohol, Anionic, Cationic and Nonionic Surfactants, and Chelate Complexes for Calcium and Magnesium Ions As the chelating agent to be generated, a phosphonic acid chelating agent, an organic acid having a hydroxyl group, or the like can be added.

  Examples of the present invention applied to chemicalless lithographic printing plates capable of development processing will be described below. The present invention is not limited to this embodiment. In the examples,% represents mass%.

(Preparation of photosensitive lithographic printing plate)
A coating solution prepared by the following hydrophilic layer formulation on a polyester film support having a thickness of 175 μm was applied at 8 g / m ² (moisture coating amount), dried for 10 minutes in a dryer at 50 ° C. and hydrophilic. A sample coated with a conductive layer was obtained. Further, the dried product was heated in a dryer at 50 ° C. for 2 days.

<Hydrophilic layer formulation>
Water-soluble polymer WP-4 (10% solution) 1g
Inorganic fine particles Colloidal silica (Snowtex 20 manufactured by Nissan Chemical Industries, Ltd.)
Particle size 10-20nm 20% aqueous solution 15g
Cross-linking agent H-9 0.5g
pH adjuster (pH value adjusted to 5.0 with aqueous sodium hydroxide or sulfuric acid)
Ion exchange water 10ml

<Photosensitive layer>
On the above hydrophilic layer coating sample (surface of the hydrophilic layer), after the preparation with the following photosensitive layer formulation, the photosensitive layer is coated so as to be 21.5 g / m ² (moisture coating amount) with a wire bar. And dried for 3 minutes in a dryer at 70 ° C. Further, a protective layer is applied on the photosensitive layer by the following protective layer formulation so as to be 30 g / m ² (moisture application amount), followed by drying for 10 minutes in a dryer at 70 ° C. A printed version was obtained.

<Photosensitive layer formulation>
1 g of sulfonic acid type polymer SP-1
Photopolymerization initiator BC-4 0.1g
Photopolymerization initiator T-8 0.1g
Sensitizing dye S-19 0.05g
Colorant Victoria Blue 0.2g
Acetone 5ml
5 ml of ethanol
Tetrahydrofuran 10ml

<Over layer>
1g made by PVA-117 Kuraray Co., Ltd.
Ion exchange water 20ml

<Exposure test>
The obtained photosensitive lithographic printing plate was exposed to an image of 2400 dpi 175 line at an exposure amount of 100 μJ / cm ² using VIPLAS manufactured by Mitsubishi Paper Industries Co., Ltd. equipped with a 405 nm violet laser.

<Development processing>
Using the exposed photosensitive lithographic printing plate, water was poured into a developing tank and a washing tank of the plate making apparatus shown in FIG. 1 of the present invention, and development processing was performed with the photosensitive layer facing upward. The developing tank is provided with a Molton roller having the diameter shown in Table 1 in the latter half of the processing step (4/5 position from the inlet side with respect to the length in which the developing solution is immersed). did. In the rinsing tank, room temperature water was showered and washed on the front and back of the printing plate, and then dried by blowing hot air of 40 ° C. The development processing conditions were set such that the Morton roller rotation speed S (rpm) shown in Table 1 and the photosensitive lithographic printing plate conveyance speed P (mm / second) were set, and the development processing was performed. The Molton roller was rotated in the same direction as the conveying direction of the photosensitive lithographic printing plate, and the contact pressure between the Molton roller and the photosensitive lithographic printing plate was set to 0.3 kg / 10 cm.

<Development unevenness>
The non-image area of the printing plate after the above processing is visually observed, and development unevenness between the non-image area and the image area (whether there is a residual film in the non-image area or whether there is peeling or scratches in the image area) No) was evaluated according to the following criteria. The results are shown in Table 1. Note that the larger the evaluation standard value, the better the development unevenness.
3: No development unevenness 2: Almost no development unevenness 1: Partially uneven

  The printing plates obtained by the development treatments 1 to 28 shown in Table 1 were subjected to a printing test using a print master QM46 (manufactured by Heidelberg) offset printing machine. The fountain solution used was 2% by weight Astro Mark 3 (manufactured by Nikken Chemical Research Co., Ltd.), and the ink was BEST ONE (manufactured by T & K TOKA Co., Ltd.).

<Evaluation criteria for printing durability>
In the printed matter obtained by printing more than 20,000 sheets, the solid image was visually observed for defects, and the printing durability of the image portion was evaluated according to the following criteria. The results are also shown in Table 1. The larger the evaluation standard value, the better the printing durability.
5: No defect in the image area even when the image area is 20,000 sheets or more 4: Defect occurs in the image area between 15,000 sheets and less than 20,000 sheets 3: 10,000 sheets to less than 15,000 sheets The image part is defective between 2: 5000 sheets and less than 10,000 sheets. The image part is defective between 1: 5000 sheets and less than 1: 5,000 sheets.

  From the test results in Table 1, development unevenness is improved by setting the relationship between the transport speed P (mm / second) of the photosensitive lithographic printing plate and the rotational speed S (rpm) of the Morton roller to S / P = 20-40. It can be seen that excellent printing durability can be obtained.

DESCRIPTION OF SYMBOLS 1 Development part 2 Rinse part 3 Drying part 6 Drying mechanism 7 Exposure apparatus 9 Photosensitive material processing apparatus 10 Introduction guide 11 Introduction roller 22 Developing tank 23 Rinse tank 33 Scrub roller 35 Diaphragm roller 41 Pump 46 Waste liquid tank M Photosensitive planographic printing plate

Claims (1)

  A photosensitive lithographic printing plate having at least a hydrophilic layer on a plastic film support and at least a photosensitive layer on the hydrophilic layer is immersed in a developer, and the photosensitive lithographic printing plate on the side having the photosensitive layer is immersed. In the development processing method of a photosensitive lithographic printing plate in which the surface is rubbed with a scrub roller, the relationship between the conveying speed P (mm / second) of the photosensitive lithographic printing plate and the rotational speed S (rpm) of the scrub roller, and the value of S / P is A developing method for a photosensitive lithographic printing plate, characterized in that it is 20-40.

Images