JP4198017B2 - Lithographic printing plate - Google Patents

Description

  The present invention relates to a lithographic printing plate using a roughened and anodized aluminum as a support, and more particularly to an aluminum lithographic printing plate using a silver complex diffusion transfer method.

  For lithographic printing plates using the silver complex diffusion transfer method (DTR method), published by Focal Press, London New York (1972), written by Andre Lot and Edith Weide, `` Photographic Silver Halide Diffusion Processes '', Some examples are described on pages 101-130.

  As described therein, the lithographic printing plate using the DTR method includes a two-sheet type in which a transfer material and an image receiving material are separated, or a mono-sheet type in which they are provided on a single support. Two methods are known. The two-sheet type planographic printing plate is described in detail in JP-A-57-158844. The mono sheet type is described in detail in Japanese Patent Publication Nos. 48-30562, 51-15765, JP-A-51-111103, 52-150105 and the like.

Monosheet type lithographic printing plates using a silver complex diffusion transfer method using an aluminum plate as a target for the present invention are disclosed in JP-A-57-118244, 57-158844, 63-260491, It is described in detail in each publication. A physical development nucleus is supported on a roughened and anodized aluminum support, and a photosensitive silver halide emulsion layer is further provided thereon. According to them, after exposing the lithographic printing plate to DTR development and then removing the constituent layers such as the silver halide emulsion layer by washing with washing water, an aluminum support carrying the transferred silver image remains. Is used as a lithographic printing plate.

  In general, the development processing is performed using an automatic developing machine. At this time, when the lithographic printing plate is continuously developed, the components of the constituent layers of the lithographic printing plate removed after the DTR development gradually accumulate in the washing tank, and bubbles are generated from the washing tank. The bubbles flowed into the developing tank, often causing trouble during plate making. This effect appears as unevenness in the shadow portion when the printing plate after development processing is printed.

  Solutions to the above problems are described in, for example, Japanese Patent Application Laid-Open Nos. 11-218934 and 7-281442. (Patent Documents 1 and 2) The former discloses a method using a non-ionic surfactant for washing water, and the latter discloses a method using silicone oil or the like for washing water. However, when these were added to the washing water, the solubility in water and the defoaming effect itself were not sufficient, and it was not possible to reach a satisfactory level when the lithographic printing plate was processed continuously. . Further, in order to obtain a sufficient defoaming effect with such washing water, a larger amount of washing water replenishment is required, which is not economical. Further, when an amount capable of obtaining an antifoaming effect is added to the lithographic printing plate, an application failure occurs due to the antifoaming agent, which is not realistic.

On the other hand, JP-A-2002-99091 (Patent Document 3) discloses an oil dispersion on a lithographic printing plate having a physical development nucleus layer between a roughened and anodized aluminum support and a silver halide emulsion layer. However, there is no description on the antifoaming agent.
Japanese Patent Laid-Open No. 11-218934 (2nd to 3rd terms) Japanese Patent Laid-Open No. 7-281442 (second to third terms) JP 2002-99091 (first and second items)

  An object of the present invention is to provide a lithographic printing plate that suppresses the generation of bubbles generated in a washing tank when a lithographic printing plate is continuously processed using an automatic developing machine, and does not cause development unevenness.

  The object is to provide a lithographic printing plate having a physical development nucleus layer between a roughened and anodized aluminum support and a silver halide emulsion layer, with at least one layer on the aluminum support of the lithographic printing plate. It was solved by using a lithographic printing plate characterized by containing an oil dispersion containing an antifoaming agent.

  Suppresses the generation of bubbles in the washing layer when lithographic printing plates are continuously processed using an automatic developing machine, eliminating development unevenness, especially unevenness in shadows when printing plates after development processing. It was.

The present invention will be described in detail below.
The antifoaming agent to be encapsulated in the oil dispersion of the present invention is not particularly limited. For example, a new edition of the surfactant handbook (editor) published by Engineering Books Co., Ltd. The antifoaming agents described in the items 190 to 195 can be used. Preferred examples include acetylene-based nonionic surfactants, acetylene glycol-based surfactants, polyoxyalkylene glycol derivatives, and the like, and a sufficient defoaming effect was obtained when a lithographic printing plate was continuously processed with an automatic processor. However, these antifoaming agents having a very high defoaming effect have extremely low solubility in water and cannot be directly added to the hydrophilic colloid layer of the lithographic printing plate.

  By adding the above preferred antifoaming agent in the form of an oil dispersion to the hydrophilic colloid layer of the lithographic printing plate, the present inventors continuously processed the lithographic printing plate with an automatic processor without causing coating failure. It was found that a sufficient defoaming effect was obtained. An oil dispersion suitable for the present invention can be achieved by utilizing the technique in the oil protection system of oil-soluble couplers described in US Pat. No. 2,322,027. In the case of the present invention, an oil-soluble coupler is not necessary.

  A method in which the oil dispersion is mechanically refined with the aid of a surfactant and dispersed in a binder such as gelatin is suitable. The oil dispersion preferably has an average oil particle size of 5 μm or less, particularly 0.1%. ˜2 μm is preferred. By adding such an oil dispersion to any one of the silver halide emulsion layer, intermediate layer, protective layer, etc., bubbles in the washing tank generated when the lithographic printing plate is continuously processed by an automatic processor. Generation can be suppressed, and development unevenness can be prevented. In order to obtain the desired antifoaming effect without adversely affecting the printing durability, it is preferably added to an intermediate layer between the physical development nucleus layer and the silver halide emulsion layer.

  As the oil of the oil dispersion used in the present invention, a compound having a boiling point of 100 ° C. or higher is used, and a compound having a boiling point of 180 ° C. or higher is particularly preferable. Although the specific example of oil is described below, it is not limited to these.

  <Oil specific example> tricresyl phosphate, diethylene glycol diethyl ether, triethylene glycol monobutyl ether, polyethylene glycol monohexyl ether, polypropylene glycol dibenzoate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, diamyl naphthalene, monocaprin, Diproline, dicaprin, triacetin, tripalmitin, palmitooleolinorenin, trilaurin, tricaprin, dipropyl adipate, dibutyl succinate, diisopropyl sebacate, octyl stearate, linseed oil, soybean oil, sesame oil, sunflower oil, cottonseed oil, sesame oil, There are rapeseed oil, olive oil, camellia oil, castor oil, etc., and two or more kinds may be used in combination.

  The oil dispersion preferably contains 1 mg to 1 g of oil in the oil dispersion per square meter of the lithographic printing plate, and particularly preferably 10 mg to 200 mg per square meter. The antifoaming agent to be included in the oil dispersion is preferably contained in an amount of 0.2 mg to 500 mg per square meter, and particularly preferably 1 mg to 100 mg per square meter.

  The type of silver halide emulsion used in the present invention is selected from generally used silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodobromide, silver iodobromide and the like. The emulsion type may be either a negative type or a positive type. For the grain formation of the silver halide emulsion used in the present invention, methods well known in the art such as forward mixing, back mixing and simultaneous mixing are used. In particular, it is preferable to use a so-called controlled double jet method, which is one of the simultaneous mixing methods, and maintains the pAg in the liquid phase in which particles are formed, in order to obtain the desired sensitivity and contrast with good reproducibility. In this case, each particle has a coefficient of variation represented by {(standard deviation of particle diameter) / (average particle diameter)} × 100 of 15% or less.

The silver halide emulsion grains used in the present invention are preferably doped with iridium ions in order to give high sensitivity in high-intensity short-time exposure with laser light. In general, the doping amount is preferably 10 ⁻⁸ to 10 ⁻⁵ mol per mol of silver halide. Further, for various purposes, a cadmium salt, a lead salt, a zinc salt, a thallium salt, an iron salt and a complex salt thereof may be contained.

  The silver halide emulsion used in the present invention is preferably sensitized with various chemical sensitizers, and is described in the literature cited in Research Disclosure Item 308119 III-A (December 1989, P.993). As described above, methods commonly used in the industry such as sulfur sensitization, selenium sensitization, and noble metal sensitization can be used singly or in combination. A compound, a thioether compound, an azaindene compound, a thiosulfonic acid compound and the like can also be present.

The spectral characteristics of the silver halide emulsion of the present invention can be adjusted according to the laser exposure apparatus to be used. For example, there are He / Ne laser (632 nm), laser diode (680 nm) or LED (670 or 780 nm), argon laser (488 nm), blue semiconductor laser (405 nm), and the like. In the present invention, sensitizing dyes that impart maximum spectral sensitivity to silver halide in the above-mentioned wavelength region are disclosed in, for example, JP-A Nos. 2-251853, 3-274055, 4-9853, and 9-9. The sensitizing dyes represented by the following chemical formula 1 described in No. 244196, No. 9-6005, No. 8-248637, No. 13-350267, and Japanese Patent Application No. 2002-222244 can be used. Of course, the present invention is not limited to these examples. The amount added can vary widely, but good results have been found to be 1 × 10 ⁻⁶ to 1 × 10 ⁻² mole, more preferably 5 × 10 ⁻⁴ to 1 × 10 ⁻² mole per mole of silver halide Can be obtained when a relatively large amount of sensitizing dye is added. The optimum addition amount varies depending on the conditions of the silver halide emulsion, such as the halogen composition, the average grain size of the silver halide grains, and the crystal habit.

In the general formula (I), Z ₁ represents an atomic group necessary for forming a 5- or 6-membered nitrogen-containing heterocycle, Q ₁ represents O, S, NR ₁₁ , Q ₂ represents O, S , NR ₁₂ . R ₁₁ and R ₁₂ are a hydrogen atom, an alkyl group, an aryl group, an organic group containing an ethyleneoxy group, an organic group containing a thioether group, an organic group containing an amino group, an organic group containing a heterocyclic ring, or an acetal group. Represents an organic group containing However, at least one of Q ₁ and Q ₂ represents NR ₁₁ or NR ₁₂ , and at least one of R ₁₁ and R ₁₂ is an organic group containing an ethyleneoxy group, an organic group containing a thioether group, or an organic group containing an amino group. , An organic group containing a heterocycle, or an organic group containing an acetal group. M ₁ represents a counter ion for neutralizing the charge of the molecule.

In the present invention, the silver halide emulsion layer may contain benzotriazole or a derivative thereof, a nitrogen-containing heterocyclic compound having a mercapto group or a thione group. The amount 1 to 100 mg / m ^2, preferably from 5 to 30 mg / m ^2.

  Examples of the benzotriazole derivative include 5-methylbenzotriazole, 5-chlorobenzotriazole and the like. The heterocyclic ring of the nitrogen-containing heterocyclic compound having a mercapto group or a thione group includes imidazole, imidazoline, thiazole, thiazoline, oxazole, oxazoline, pyrazolidone, trizol, thiadiazole, oxadiazole, tetrazole, pyridine, pyrimidine, pyridazine, pyrazine, There are triazines, among which imidazole, triazole and tetrazole are preferred.

  Specific examples of the nitrogen-containing heterocyclic compound having a mercapto group or a thione group are given below. 2-mercapto-4-phenylimidazole, 2-mercapto-1-benzylimidazole, 2mercapto-1-butyl-benzimidazole, 1 ethyl-2 mercapto-benzimidazole, 2 mercapto-benzimidazole, 1,3 diethyl- Benzimidazoline 2-thione, 1,3 dibenzyl-imidazolidine-2-thione, 2,2-dimercapto-1,1′-decamethylene-diimidazoline-2-thione, 2 mercapto-4-phenylthiazole, 2 -Mercapto-benzothiazole, 2-mercaptonaphthothiazole, 3-ethyl-benzothiazoline-2-thione, 3-dodecyl-benzothiazoline-2-thione, 2-mercapto-4,5-diphenyloxazole, 2-mercaptobenzoxazole , 3-pentyl-be Zoxazoline-2-thione, 1-phenyl-3-methylpyrazolidone-5-thione, 3-mercapto-4-allyl-5-pentadecyl-1,2,4-triazole, 3-mercapto-5-nonyl 1,2,4-triazole, 3-mercapto-5-nonyl-5-1,2,4-triazole, 3-mercapto-4-allyl-5-pentadecyl-1,2,4-triazole, 3-mercapto- 4-amino-5-heptadecyl-1,2,4-triazole, 2-mercapto-5-phenyl-5-pentadecyl-1,3,4-thiadiazole, 2-mercapto-5-n-heptyl-oxathiazole, 2 -Mercapto-5-phenyl 1,3,4-oxadiazole, 5-mercapto-1-phenyl-tetrazole, 2-mercapto-5-nitropi Gin, 1-methyl-quinoline-2 (1H) -thione, 3-mercapto-4-methyl-6-phenylpyridazine, 2-mercapto-5,6-diphenyl-pyrazine, 2-mercapto-4,6-diphenyl 1 , 3,5 triazine, 2-amino-4-mercapto-6-benzyl-1,3,5-triazine, 1,5-dimercapto-3,7-diphenyl-S-triazolino [1,2-a] -S -Triazoline and the like.

  The silver halide emulsion of the present invention is preferably added with a dye having a maximum absorption wavelength at 450 to 750 nm to the silver halide emulsion layer or its protective layer for the purpose of enabling handling under bright safelight. The more preferable maximum absorption wavelength of the dye is 480 to 550 nm. As the dyes used in the present invention, water-soluble oxonol dyes and water-soluble azo dyes described in Japanese Patent Application No. 2001-304393 are particularly preferred. In addition, oxonol dyes, hemioxonol dyes, styryl dyes, merocyanine dyes, cyanine dyes and Azo dyes and the like are included. Specifically, for example, a pyrazolone oxonol dye described in US Pat. No. 2,274,782, a diarylazo dye described in US Pat. No. 2,956,879, US Pat. No. 3,423,207, The styryl dye and butadienyl dye described in US Pat. No. 3,384,487, the merocyanine dye and oxonol dye described in US Pat. No. 2,527,583, and the enaminohemioxo described in US Pat. No. 3,976,661 Nol dyes and British Patent Nos. 584,609, 1,177,429, JP-A-48-85130, 49-99620, 49-114420, US Pat. No. 2,533,472, 3,148,187, 3,177,078, 3,247,127, 3,540,887, 3,575,70 No., dyes described in JP same second 3,653,905 is used. The dye having a maximum absorption wavelength of 450 nm to 750 nm is a wavelength at which the spectral absorption of the added dye is maximized, and is defined as an absorption wavelength in a state of being dispersed in a binder to form a film.

Further, for the same purpose as the dye, a water-insoluble pigment having a maximum absorption wavelength of 450 to 750 nm can be used. For example, organic pigments described in JP-A-9-281708 can be used. The size of the pigment is preferably about 0.05 μm as the primary particles, and is used as an aqueous dispersion having an average particle size of 0.5 μm or less by dispersing in water using a dispersant such as nonionic or anionic surfactant. Is preferred. In particular, a pigment using an anionic surfactant is preferable. However, depending on the type of pigment and dispersion conditions, it usually causes secondary or tertiary aggregation in water, and is about 0.2 to 2.0 μm. The amount of time to be added to the silver halide emulsion layer is preferably ^{0.001g / m 2 ~10g / m 2} , particularly preferably ^{0.01g / m 2 ~2g / m 2} .

  Further, by adding an organic desensitizer to the silver halide emulsion layer in combination with a dye having a maximum absorption wavelength of 450 nm to 750 nm, the safelight resistance can be further improved.

Usually, the wavelength with the least absorption of the silver halide emulsion used in the plate is selected as the safety light. For this reason, the frequency with which safety light is absorbed by silver halide to form photoelectrons is very low. On the other hand, imagesetter - To image exposure in the convenience of performing high-definition exposure of a large area, the exposure time of a point is very short, typically 10 ^-3 seconds or less, there is only 10 ^-7 seconds to exposure time in some cases . Thus, when an appropriate amount of organic desensitizer is adsorbed on silver halide only when the exposure time of image exposure and safety light is different, it occurs in silver halide when safety light is irradiated. Although almost all of the photoelectrons are taken up by the organic desensitizer, a large amount of photoelectrons are generated in an instant during image exposure, so all the photoelectrons cannot be taken up by the organic desensitizer. Since there is no illuminance failure, the sensitivity hardly changes. Further, it is known that a rhodium salt is used in the light-sensitive material for a bright room in order to lower the sensitivity, but such an inorganic desensitizer does not exhibit the above-described effect of the present invention.

  The organic desensitizer used in the present invention is generally known to be used directly in a positive silver halide emulsion, and has a positive sum of a polarographic anode potential and a polarographic cathode potential. Methods for measuring these oxidation-reduction potentials are described in, for example, US Pat. No. 3,501,307. Specific examples of such organic desensitizers are described in many patent specifications and literatures, all of which have the same action in the present invention. Sho 39-20261, Sho 40-26751, Sho 43-13167, Sho 45-8833, Sho 47-8746, Sho 47-10197, Sho 50-37530, Sho 48-24734, Sho 49 -84639, 56-142525, U.S. Pat. Nos. 2,271,229, 2,541,472, 3,035,917, 3,062,651, 3, 124,458, 3,326,687, 3,671,254 and the like can be used. Specific examples are shown below. 1,3-diethyl-1'methyl-2'-phenylimidazo [4,5-b] -quinoxalino-3'-indolocarbocyanine iodide. Pinacryptol yellow and pinacryptol green. 1,1 ',-3,3,3', 3'-hexamethyl-5,5'-dinitroindocarbocyanine / P-toluenesulfonate. 5,5-Dichloro-3,3'-diethyl-6,6'-dinitrothiacarbocyanine iodide. 1,1 ', 3,3'-tetraethylimidazo [4,5-b] quinoxanocarbocyanine chloride. 5-m-nitrobenzylidene rhodanine. 6-chloro-4-nitrobenzotriazolium. 1,1'-dibutyl-4,4'-bibilidinium dibromide. 4- (Pn-amyloxyphenyl) -2,6-di (P-ethylphenyl) thiapylium perchlorate. 2-mercapto-4-methyl-5-nitrothiazole. Fenosafranine.

  The organic desensitizer is used in an amount of 0.1 to 200 mg, preferably 10 to 150 mg per mole of silver halide.

  The organic desensitizer used in the present invention may be dissolved in an appropriate solvent such as water, alcohol (for example, methanol, ethanol, propanol, etc.), acetone, or a mixed solvent thereof and added to the silver halide emulsion layer. it can.

  The silver halide emulsion used in the present invention includes other stabilizers, antifoggants, irradiation inhibitors, film property modifiers, surfactants, matting agents, developing agents, and the like used for general photography. An agent can be included.

  The physical development nuclei of the physical development nuclei layer used in the present invention may be those used in a known silver complex diffusion transfer method. For example, colloids such as gold and silver, water-soluble salts such as palladium and zinc, and sulfides. Mixed metal sulfides can be used. Various hydrophilic colloids can also be used as the protective colloid. For details and manufacturing methods, see, for example, “Photographic Silver Halide Diffusion Processes”, published by Focal Press, London New York (1972), by Andre Lot and Edith Weide.

In the present invention, nitrate ion or nitrite ion may be contained in the physical development nucleus layer. The amount to be contained the nitrate ion or nitrite ion is preferably 0.05 mmol / m ² or more, more preferably in the range of 0.5 ~5mmol / m ²

  Developers used in the present invention include developing agents such as polyhydroxybenzenes, 3-pyrazolidinones, alkaline substances such as potassium hydroxide, sodium hydroxide, lithium hydroxide, tribasic sodium phosphate, or amine compounds. Fixing agents such as sodium sulfite, thickeners such as carboxymethyl sesulose, antifoggants such as potassium bromide, 1-phenyl-5-mercaptotetrazole, development modifiers such as additives such as polyoxyalkylene compounds, etc. Can be included.

  The pH of the developer is usually about 10 to 14, preferably about 12 to 14, but pretreatment (for example, anodizing) conditions of the lithographic printing plate aluminum support used, photographic element, desired image, in developer Depending on the type and amount of various compounds, development conditions, and the like.

  Washoff for removing the gelatin layer can be performed by rinsing with running water at a temperature of about 20 to 30 ° C.

  The aluminum support used in the present invention is a roughened and anodized aluminum plate having 1.0 g or more, preferably 1.5 to 5.0 g of porous aluminum oxide per square meter. It is done. The support used in the present invention is subjected to degreasing treatment, roughening treatment, anodizing treatment, etc., which are usually used in this technical field. At least the roughening treatment and anodizing treatment are performed in this order. Use the support made.

  In order to remove fatty substances from the surface of the aluminum plate, degreasing treatment includes solvent degreasing such as trichlene and thinner, emulsion degreasing, acid degreasing, alkaline degreasing mixed with surfactant, kerosene, triethanolamine and sodium hydroxide. and so on. The roughening treatment for improving the adhesion to the silver halide emulsion layer and improving the water retention includes mechanical treatment, chemical treatment, and electrochemical treatment. These treatments are used alone or in combination. I do. In particular, it is preferable to combine mechanical polishing in terms of cost. The shape of the surface is generally represented by a roughness meter, but the size is suitably a center line average roughness; Ra value of 0.3 to 1.0 μm.

  In the present invention, the desmut refers to a chemical etching process performed between roughening and anodizing. Desmutting can be performed using an acid or an alkali, but acid treatment is preferred. The concentration of the liquid is related to the treatment, and the total of acid or alkali is about 5 to 40%, and the treatment time is preferably 30 seconds to 2 minutes. The treatment temperature is preferably 40-60 ° C.

After performing such roughening treatment and desmut treatment, anodization treatment is performed. As the electrolytic solution for anodic oxidation, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, organic acid (for example, sulfamic acid, benzenesulfonic acid, etc.) or a mixture thereof is preferable, and an acid with low solubility of the generated oxide film is particularly preferable. . The thickness of the anodic oxide film is changed by the current density and time, it is adjusted appropriately by printing grade of the printing plate, 3 g / m ² or less, preferably ^{2.8g / m 2 ~1g / m 2} , more preferably preferably It will be 2.3g / m ² ~1g / m ² necessary. The amount of these anodized films can be measured based on JIS H86807 “film mass method”.

  Further, after the anodizing treatment, a post-treatment can be performed as necessary. As the post-treatment, methods known to those skilled in the art, for example, post-treatment with inorganic salts such as silicate treatment and hydrofluoric zirconate treatment, organic polymer treatment such as gum arabic, polyvinyl phosphonic acid and polyvinyl sulfonic acid, hydration There is a sealing treatment.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In addition,% shows the mass% unless there is a notice.

<Preparation of aluminum support with physical development nuclei>
A 1050 aluminum plate is degreased with a 4% aqueous sodium hydroxide solution at 50 ° C. for 1 minute, washed with water, polished with a rotating nylon brush using a 400 mesh pumiston suspension, and washed in a 2.5% aqueous hydrochloric acid solution. An electrolytic surface roughening treatment was performed at an AC density of 50 A / dm ² at 60 ° C. for 60 seconds and desmutted with 20% phosphoric acid at 50 ° C. for 1 minute. Thereafter, anodization was performed in a 25% sulfuric acid solution at a temperature of 20 ° C., an electric density of 3 A / dm ² , and a treatment time of 45 seconds. Thereafter, palladium sulfide nuclei were applied as physical development nuclei on the prepared aluminum support so that the coating amount was 3 mg / m ² to obtain an aluminum support with physical development nuclei.

<Preparation of oil dispersion A>
An oil dispersion A was prepared using a polyoxyalkylene glycol derivative commercially available from Nippon Oil & Fats Co., Ltd., and deform NGL6003. 6.0 g of NGL6003 was collected and dissolved in 10 g of ethyl acetate. To this solution, 25 g of tricresyl phosphate was added and dissolved. An aqueous solution containing 250 g of a 10% gelatin solution and 5 g of a surfactant (anionic surfactant: 20-fold diluted sodium sulfosuccinate di (2-ethyl) hexyl) was kept at 40 ° C. An oil in which a foaming agent is dissolved is added, and TK. Using a HOMO MIXER, the mixture was dispersed with the stirring dial 6 for 30 minutes. After dispersion, water was added to make 300 g. When the particle diameter of the obtained oil dispersion was measured using a laser diffraction / scattering particle size distribution analyzer HORIBA LA910 manufactured by Horiba, Ltd., the median diameter was 1.09 μm.

<Preparation of oil dispersion B>
Oil dispersion B was prepared in the same manner as oil dispersion A using acetylene-based nonionic surfactant and olefin SPC commercially available from Nissin Chemical Industry Co., Ltd. The particle diameter of the obtained oil dispersion was measured using a laser diffraction / scattering particle size distribution analyzer HORIBA LA910 manufactured by Horiba, Ltd. As a result, the median diameter was 1.10 μm.

<Creation of intermediate layer coating liquid>
2 g of sodium nitrate was added to 10 g of a 10% polyvinylpyrrolidone aqueous solution, and water was added to make 80 g of the intermediate layer coating solution 1. Similarly, an intermediate layer coating solution 2 in which 6.0 g of the oil dispersion A was added to the intermediate layer coating solution 1 and an intermediate layer coating solution 3 in which 6.0 g of the oil dispersion B were added were prepared. Further, an intermediate layer coating solution 4 was prepared by directly adding 0.12 g of deformed NGL6003 to the intermediate layer coating solution 1.

<Preparation of silver halide emulsion layer>
The silver halide emulsion was prepared by using photographic gelatin as a protective colloid, an average particle size of 0.3 μm by a control double jet method, and chloride doped with 0.006 mmol of potassium hexachloroiridium (III) per mol of silver. A silver chlorobromoiodide emulsion comprising 84.8 mol% silver, 15 mol% silver bromide and 0.2 mol% silver iodide was prepared. The emulsion was then flocculated and washed with demineralized water. The emulsion was further subjected to gold-sulfur sensitization, then added with photographic gelatin and stabilizer, and spectral sensitization using 8 × 10 ⁻⁴ mol of sensitizing dye represented by the following chemical formula 2 per mol of silver halide. Further, 150 mg of an organic desensitizer represented by the following chemical formula 3 was added per mole of silver halide. 30 mg / m ^{2 of} filter dyes represented by the chemical formulas 4 and 5 were added thereto to obtain a silver halide emulsion layer.

<Preparation of planographic printing plates 1, 2, 3, 4>
On the aluminum support with physical development nuclei, 0.08 g of polyvinylpyrrolidone as an intermediate layer was coated with 0.08 g of polyvinylpyrrolidone per 1 m ² , and the silver halide emulsion layer was converted to a silver amount in terms of silver halide. A lithographic printing plate 1 coated to 2.0 g / m ² was prepared. Similarly, after using the intermediate layer coating solution 2 to coat 0.08 g of polyvinylpyrrolidone per 1 m ² , the silver halide emulsion layer was coated so that the silver halide amount was 2.0 g / m ^{2 in} terms of silver amount. After applying 0.08 g of polyvinylpyrrolidone per 1 m ² using the lithographic printing plate 2 and the intermediate layer coating solution 3, the silver halide emulsion layer has a silver halide content of 2.0 g / m in terms of silver amount. ² is applied to the lithographic printing plate 3 and the intermediate layer coating solution 4 is coated with 0.08 g of polyvinylpyrrolidone per 1 m ² , and then the silver halide emulsion layer is converted into a silver amount. A lithographic printing plate 4 was prepared by coating at 2.0 g / m ² . However, the lithographic printing plate 4 has a coating failure in which many portions where the silver halide emulsion layer is locally missing are observed on the surface of the lithographic printing plate after coating the silver halide emulsion layer. Could not get the version.

  The lithographic printing plate used for the test was developed by the following method. P-α880 manufactured by Mitsubishi Paper Industries was used as the plate-making processor. This consists of a development process (22 ° C), a washing process (washing off the emulsion layer with a scrub roller while spraying 35 ° C washing water), a finishing process (21 ° C, shower) and a drying process. ing. The washing process is a closed type in which 20L of washing water stored in the storage tank is circulated with a pump, showered on the planographic printing plate, filtered through a filtration filter, collected in the storage tank, and reused. . The processing speed was adjusted so that the development processing step was 10 seconds.

The composition of the developer, washing solution and finishing solution used is as follows.
<Developer>
Sodium hydroxide 30g
Polystyrene sulfonic acid and maleic anhydride copolymer
(Average molecular weight 500,000)
10g
Hydroquinone 15g
1-phenyl-3-pyrazolidinone 3g
100 g of anhydrous sodium sulfite
Monomethylethanolamine 50g
2-mercapto-5-nheptyloxadiazole 0.1 g
5-mercapto-1-phenyltetrazole 0.8 g
5-methylbenzotriazole 0.2g
Sodium thiosulfate 20g
Amino trimethylene phosphonic acid 7g
Calcium sulfate 1g
Bring to 1000 mL with deionized water.
pH (25 ° C) = 13.3

<Washing liquid 1>
2-mercapto-5-nheptyloxadiazole 0.5 g
20g triethanolamine
Potassium bisulfite 6g
Amino trimethylene phosphonic acid 20g
Proteolytic enzyme 1g
Add water to adjust total volume to 1000cc. The pH was adjusted to 7.4.
Bioprolase AL-15 (bacterial proteinase, manufactured by Nagase Sangyo Co., Ltd.) was used as a proteolytic enzyme.
<Finishing liquid>
Phosphoric acid 100g
N-methylethanolamine 30g
2-mercapto-5-nheptyloxadiazole 0.5 g
90g of polypropylene glycol alkyl ether
Sodium nitrate 20g
Arabic gum 50g
Ethylenediaminetetraacetic acid 0.5g
Proteolytic enzyme 1g
Bring to 1000 mL with deionized water.
The pH was adjusted to 5.4.

  Further, a water washing solution obtained by adding 10 mg of Disform NGL6003 to 1000 ml of the water washing solution was prepared as a water washing solution 2, and a water washing solution obtained by adding 10 mg of olefin SPC was prepared as a water washing solution 3.

  A running test was performed using a combination of a lithographic printing plate and a washing solution as described in Table 1. In the test, the prepared lithographic printing plate (size: 670 × 560 mm) was subjected to scanning exposure using a scanning exposure apparatus (Mitsubishi Paper Industries Image Setter: VIPLAS) equipped with a purple-blue semiconductor laser, and 75 over the entire scanning exposure area. % Flat net was output, and continuous processing was carried out with a plate-making processor Mitsubishi Paper Industries P-α880. At this time, the replenishing amounts of the developer and the washing solution are both 100 ml per square meter of the lithographic printing plate.

  The lithographic printing plates obtained in the running tests 1 to 5 thus performed were mounted on an offset printing machine (Sprint 226 manufactured by Comori Corp.) for printing. The ink used was GEOS-G (cyan) H type manufactured by Dainippon Ink. The value of the printing result in the table indicates the number of processed sheets from the start of the test during the running process in which unevenness began to appear on the printed matter.

From Table 1, it can be seen that unevenness of printed matter is improved by the present invention.

Claims (1)

In a lithographic printing plate having a physical development nucleus layer between a roughened and anodized aluminum support and a silver halide emulsion layer, at least one layer on the aluminum support of the lithographic printing plate contains an antifoaming agent A lithographic printing plate comprising an oil dispersion containing