JPH0365543B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of the Invention] The present invention relates to a photosensitive lithographic printing plate (referred to as a "Presensitized Plate"), which is composed of a silver halide-containing photosensitive layer provided on an aluminum support having an aluminum oxide coating on the surface thereof, and is different from a PS plate. ), which prevents white and black spots that occur during the plate-making process, as well as many minute dot-like stains (hereinafter referred to as "dot-like stains") that occur over the entire surface of printed matter. It is possible to create a lithographic printing plate that can be printed with excellent image quality.
This is related to the PS version. [Prior Art] PS plates in which a silver halide-containing photosensitive layer is provided directly or via a non-silver photosensitive layer on an aluminum support having an aluminum oxide coating on the surface are disclosed, for example, in British Patent Nos. 1571155 and 1567844. ,same
No. 1227603, Japanese Patent Publication No. 55-166645, No. 56-60442
No. 56-50330, No. 57-48733, etc. However, in this type of PS plate, spots often occur during the manufacturing process, probably due to some kind of interaction between the metal aluminum of the aluminum support or impurities and the silver halide grains. The occurrence of such spots was reported in Japanese Unexamined Patent Application Publication No. 1987-
This can be prevented by incorporating a mercapto compound having a specific chemical structure into the photosensitive layer as described in No. 48733. However, even in the PS version where the occurrence of such spots has been prevented, over time,
New problems have been discovered in which white spots occur in printed areas and dotted stains occur in non-printed areas. It has been found that the use of mercapto compounds not only cannot prevent these problems, but also promotes the occurrence of the white spots. It has also been found that such an adverse effect is particularly noticeable when a direct positive type silver halide containing photosensitive layer is used. [Object of the invention] The present invention provides a PS in which such problems are solved.
The purpose is to provide a version. That is, a first object of the present invention is to provide an improved PS plate that does not cause spot stains and does not generate white spots in the image area even after natural aging. The second objective is to develop a PS with a direct positive silver halide-containing photosensitive layer that has high sensitivity and improved stability over time.
The purpose is to provide a version. [Structure of the Invention] As a result of various studies, the present inventors have discovered that the above object can be achieved by using a specific compound containing a triazine ring. That is,
The present invention provides a photosensitive lithographic printing plate having at least a silver halide-containing photosensitive layer on an aluminum support having an aluminum oxide coating on the surface, wherein the average weight of the aluminum oxide coating is at least 1 g/
m ² and at least one layer on the support contains a compound having a repeating unit represented by the following general formula (). Here, R ₁ is −OR, −SR,

〔Effect of the invention〕

The features of the present invention will be explained. When a silver halide photosensitive layer is provided in direct contact with a metallic aluminum support, fogging occurs. If the aluminum surface is coated with aluminum oxide by anodizing or the like, fogging can be significantly suppressed. The inventor tried to make the grained support as uniform as possible by applying 1 g/
It has been found that coating with aluminum oxide of m ² or more can almost prevent the occurrence of fog. but,
If this is left for a long time, spots will appear due to development. These spots cannot be prevented at all even by the use of compounds normally used as spot preventers in silver halide photosensitive emulsions, such as the aldoxime compounds described in US Pat. No. 3,310,405. Some black spots can be prevented when used in combination with mercapto compounds. Mercapto compounds are
Silver ions and poorly soluble mercapto silver salts are formed and precipitated, and are also used as antifoggants. In the same way, it produces silver ions and poorly soluble silver salts, and is also used as an antifoggant. For example, even if 5-bromo-benzotriazole, 6-nitro-benzotriazole, etc. are used, the occurrence of spots cannot be prevented at all. However, with the use of mercapto compounds, white spots that occur in the image area during natural aging and especially
It was difficult to prevent spot stains. By using the compounds according to the invention, it is possible to prevent not only black spots, which can be prevented by using mercapto compounds, but also white spots and punctate stains. This effect is due to the fact that when a direct positive-working silver halide-containing photosensitive layer is used, the addition of a mercapto compound prevents the occurrence of black spots, but tends to cause a large number of white spots. It has been found that the addition has a surprising effect in preventing the occurrence of white and black spots as well as dotted stains. [Example] Hereinafter, the content of the present invention will be specifically explained with reference to synthesis examples and examples of the compound represented by the general formula () used in the present invention. Note that % indicates weight % unless otherwise specified. Synthesis Example 1 (Synthesis of Compound 1) 368g of cyanuric chloride was dissolved in 1.1g of acetone,
This was gradually added to 1.5 liters of water cooled to below 10° C. with stirring. While keeping this mixture below 5°C and continuing to stir, the ethanolamine 122
g, 212 g of acidic sodium carbonate and 800 ml of water was added over 1.5 hours. After stirring for another 2 hours at the same temperature, gradually raise the temperature to about 15℃.
The mixture was stirred for 1 hour. Filter the precipitated crystals,
Recrystallization from water containing a small amount of acidic sodium carbonate yielded 253 g of 2,4-dichloro-6-hydroxyethylamino-S-triazine. It was a white crystal with a melting point (decomposition) of 117-119°C. 209 g of 2,4-dichloro-6-hydroxyethylamine-S-triazine thus obtained was mixed with 2 parts of water, stirred while maintaining the temperature at 20-25°C, and 70 g of 1,3-diaminopropane was added to the mixture. water
A solution consisting of 300 ml was added over a period of 1 hour. After the addition was complete, the temperature was raised to 30-35°C and a solution of 168 g of sodium acid carbonate and 1 part water was added over 40 minutes. After addition, gradually increase the temperature to 95-100
The mixture was stirred for 3 hours while maintaining the temperature at ℃. After cooling, the mixture was filtered, washed with water until the washing liquid became neutral, and dried. 200g of Compound 1 in the form of a white powder was obtained. Compound 1 measured in dimethylformamide at 35°C
The value of intrinsic viscosity was 0.104. Synthesis Example 2 (Synthesis of Compound 2) A mixture consisting of 250 g of 2,4-dichloro-6-hydroxyethylamino-S-triazine obtained by the same method as in Synthesis Example 1, 2 parts of acetone, and 1 part of water was added. After stirring at 20°C, a solution of 40.7 g of 1,3-diaminopropane and 200 ml of water was added dropwise over 30 minutes, and then a solution of 101 g of acidic sodium carbonate and 1 ml of water was added to the mixture for 30 minutes.
It was added over a period of minutes. After the addition was complete, the temperature was raised and stirring was continued at 40-45°C for 1 hour, cooled with ice water and filtered to obtain 232 g of white crystals. When this was recrystallized from a mixed solvent of dioxane/water = 1/1, 1,3-bis(2'-chloro-4'-hydroxyethylamino-S-triazin-6-ylamino)-propane (melting point (decomposition) 276 ℃) 184 g were obtained as white crystals. 42.5 g of 1,3-bis(2'-chloro-4'-hydroxyethylamino-S-triazin-6'-ylamino)propane thus obtained and 400 g of water.
ml of the mixture was stirred at 30-35°C, a solution of 7.4 g of ethylenediamine monohydrate and 30 ml of water was added thereto, the temperature was raised to 40-45°C and a solution of 16.8 g of acidic sodium carbonate and 120 ml of water was added. of
Added over 30 minutes. The temperature was further raised to 90 to 95°C, and the mixture was heated and stirred for 3 hours, then cooled to room temperature, filtered, washed with water, and dried. 240 g of a white powdery compound was obtained. The intrinsic viscosity of this product measured in dimethylformamide at 35°C was 0.125. Example 1 Grained JISA1050 aluminum plate
Part of the surface was corroded by immersing it in a 2% sodium hydroxide aqueous solution kept at 40°C for 1 minute. After washing with water, it was immersed in a sulfuric acid-chromic acid solution for about 1 minute to expose the pure aluminum surface. After immersing in 20% sulfuric acid kept at 30℃ and anodizing for 2 minutes under the conditions of DC voltage 1.5V and current density 3A/ ^dm2 , washing with water,
Dry. Next, add a photosensitive solution with the following composition to a dry weight of 2
A non-silver photosensitive layer was formed by continuously coating the film using a roll coater so as to obtain a coating of about ² g/m. Acetone - naphthoquinone of pyrogallol resin -
1,2-Diazide(2)-5-sulfonic acid ester (synthesized according to the method of Example 1 of US Pat. No. 3,635,709) 2.5 g Cresol-formaldehyde resin 5.0 g Methyl ethyl ketone 75 g Cyclohexanone 60 g The dry weight of the photosensitive liquid is 5.2g/
It was applied continuously so that it was in the ^2nd position and dried with hot air at a final temperature of 110°C. This sample is designated as A. An emulsion in which 20g of a copolymer of benzyl methacrylate and methacrylic acid (70% benzyl methacrylate and 30% methacrylic acid) is dissolved in 277g of ethyl acetate and dispersed in 556ml of a 10% gelatin solution using an anionic surfactant as a dispersion medium...1470g Directly below Positive photosensitive silver halide emulsion (raw milk)
…1000g pinacryptol yellow (1/250 mol water/
Methanol = 1/1 solution...144ml 1% aqueous solution of glyoxal...8ml [Raw milk] 1st solution (5 c.c. of inert gelatin and 1N solution of sodium chloride in 500 c.c. of water heated to 60℃ 2nd solution (100 g of nitric acid dissolved in 500 c.c. of water)
(dissolved by heating to ℃) and third liquid (dissolve 23 g of sodium chloride and 23 g of potassium bromide in 150 c.c. of water,
Furthermore, potassium hexachloroiridate ()
50 mg of K ₂ Ircl ₃ was added and kept at 60° C.) and was gradually added over 20 minutes with stirring. Then, add 15 c.c. of 0.2N potassium iodide solution,
I lowered the temperature and washed with water. Further melt PAg
Adjust to 4.0 and add hydrazine and gold chloride salt,
Next, the pH was adjusted to 10, aged for 10 minutes, and then neutralized to pH 6.5 using citric acid. Lower the temperature and wash with water, then add a mixture of molten sodium chloride and potassium bromide to adjust PAg to 7.0, and then add a fourth solution (75 g of inert gelatin dissolved in 300 c.c. of water). A silver halide emulsion was obtained.
The average grain size of the obtained silver halide emulsion was 0.15 microns, and substantially all the grains were regular tetragonal grains having (100) planes. Next, the following compound was added to the silver halide emulsion-containing layer of sample A, and the mixture was stirred for 30 minutes.The mixture was coated on the non-silver photosensitive layer in the same manner as sample A, and the resulting sample was dried.
Let it be G. Sample B: 3% aqueous solution of Compound 1 (synthesized according to Synthesis Example 1) ...150ml Sample C: 3% aqueous solution of Compound 2 (synthesized according to Synthesis Example 2) ...150ml Sample D: 3% aqueous solution of Compound 3 (synthesized according to Synthesis Example 1)...150ml Sample E: 3% aqueous solution of Compound 4 (synthesized according to Synthesis Example 1)...220ml Sample F: Compound 5 3% aqueous solution of Compound 6 (synthesized according to Synthesis Example 1)...200ml Sample G: 3% aqueous solution of Compound 6 (synthesized according to Synthesis Example 1)...160ml Samples A to G at room temperature for 1 day After being left to stand, the plate was made as follows. A positive image of the original text stamped on phototypesetting paper is pasted onto a mount, and then printed at 500w using a plate-making camera (Art Graphica 601, manufactured by Dainippon Screen).
The photo was taken using four halogen lamps as the light source, with an aperture of 11 and an exposure time of 25 seconds. Next, the following processing was performed using an automatic developing machine. A developer solution () with the following composition was heated at 32℃.
for 20 seconds, and then add the following fixer () at 20℃ for 10 seconds.
It lasted for a second. Next, it is passed through an ultraviolet exposure section consisting of three reflector-type mercury lamps for 15 seconds, soaked in warm water at 40 to 45 degrees Celsius, rubbed with a brush, passed through a squeeze roller, and then heated at 30 degrees Celsius with a developer () having the composition shown below. The mixture was heated for 30 seconds and then gummed to obtain a lithographic printing plate. Composition of developer () Water...700ml Metol...3.0g Sodium sulfite...45.0g Hydroquinone...12.0g Sodium carbonate (monohydrate)...80.0g Potassium bromide...2g Add water to make...1 Add this stock solution with water It is diluted (1:2) and used. Developer () JIS No. 1 Sodium silicate...100g Sodium metasilicate...50g Pure water...1800ml Fixer () Water...700ml Ammonium thiosulfate...224g Sodium sulfite...20g Add water to make...1000ml Each printing plate thus obtained by heidel
Printed using a KOR printing machine. The lithographic printing plates obtained from Samples B to G all gave prints of good image quality and had a printing life of about 110,000 copies. On the other hand, prints made using the lithographic printing plate made from Sample A produced good prints from the start of printing until 3000 copies were printed, but after that, scumming occurred.
When printing more than 5,000 copies, spot stains frequently appeared in non-image areas. Example 2 An aluminum plate was treated in the same manner as in Example 1, and then a non-silver photosensitive layer was provided on the sample. Direct positive silver halide emulsions having the following compositions H to J were added to a dry weight of 5.2 g. Coating and drying was carried out in the same manner as in Example 1 so that the coating was ² /m2. Composition H~J

[Table] The sample thus obtained was left for one day under high temperature and high humidity conditions of 50° C. to 90% RH, and then developed in the same manner as in Example 1 without being exposed to light. The degree of spots generated on the developed printing plate is shown in the table below.

[Table] From this result, in the PS version according to the present invention,
It can be seen that no spots appear even after a long period of time.

Claims (1)

[Scope of Claims] 1. A photosensitive lithographic printing plate having at least a silver halide-containing photosensitive layer on an aluminum support having an aluminum oxide coating on the surface, wherein the average weight of the aluminum oxide coating is at least 1 g/m ² 1. A photosensitive lithographic printing plate, wherein at least one layer on the support contains a compound having a repeating unit represented by the following general formula (). Here, R ₁ represents -OR, -SR, [Formula], and R and R' are respectively a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a hydroxyalkyl group, and a sulfoalkyl (or salt thereof) group. , carboxyalkyl (or salt thereof) group, aralkyl group, or sulfo (or salt thereof), carboxyl (or salt thereof), alkyl having 1 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms, or halogen It represents an aryl group having 6 to 12 carbon atoms or a cycloalkyl group with or without a - substituent, or even if R and R' together form an alkylene ring or an alkylene ring containing -O-. Often, R ₂ , R ₃ , R ₄ and R ₅ each represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and Y ₁ ,
Y ₂ , Y ₃ and Y ₄ are each a polymethylene group having 2 to 12 carbon atoms, a polymethylene group having 2 to 12 carbon atoms substituted with an alkyl group having 1 to 4 carbon atoms, or a sulfo (or salt thereof)- , represents an arylene group with or without a carboxyl (or salt thereof), alkyl having 1 to 4 carbon atoms, or halogen, or a cycloalkylene group, and Z is -O-, -SO ₂ - or −CH ₂ −,
1 and m represent 0 or 1. 2. The photosensitive lithographic printing plate according to claim 1, wherein the photosensitive lithographic printing plate has a non-silver photosensitive layer and a silver halide-containing photosensitive layer in this order on the support.