JP2000284487A - Photochemical process for planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the printing durability, the ink removability and fingerprint stain resistance of the non-image area and the thin line reproducibility of the silver image area of a planographic printing plate using an aluminum sheet as the substrate and utilizing a silver complex salt diffusion transfer process. SOLUTION: A planographic printing plate having physical developing nuclei between an anodically oxidized aluminum substrate and a silver halide emulsion layer and utilizing a silver complex salt diffusion transfer process is subjected to at least development after exposure. The substrate is an aluminum sheet having >=500 pits of 0.03-0.30 μm diameter per 100 μm2 and having 0.05-0.20 μm average diameter of the pits or an aluminum sheet having recesses whose surface area is >=50% of the total surface area. The development is carried out with a developing solution containing a dissolution inhibitor of aluminum oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of making an aluminum lithographic printing plate using an aluminum plate as a support and utilizing a silver complex salt diffusion transfer method.

[0002]

2. Description of the Related Art A lithographic printing plate using a silver complex salt diffusion transfer method (DTR method) is described in "Photographic Silver Halide," published by Focal Press, London New York (1972), by Andrelot and Edith Weide. Some examples are described in "Diffusion Processes", pp. 101-130.

As described therein, a 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 monolithic type in which they are provided on a single support. Two types of sheet type are known.
A two-sheet type lithographic printing plate is disclosed in
This is described in detail in JP-A-158844. For the mono-sheet type, see JP-B-48-30562.
No. 51-15765, JP-A-51-111103
And JP-A Nos. 52-150105.

A monosheet type lithographic printing plate utilizing an aluminum plate as a support and utilizing a silver complex salt diffusion transfer method (hereinafter referred to as an aluminum lithographic printing plate) is disclosed in Japanese Patent Application Laid-Open No. 57-118244. No. 57-158
Nos. 844 and 63-260491, JP-A-3-116
No. 151, 4-282295, U.S. Pat.
Nos. 7,131, 5,427,889 and the like.

[0005] The aluminum lithographic printing plate has a structure in which a physical development nucleus is supported on a roughened and anodized aluminum support, and a silver halide emulsion layer is further provided thereon. The general method of making a lithographic printing plate is
After exposure, the process includes development, washing (wash-off: removal of the silver halide emulsion layer), and finishing.

More specifically, a metal silver image portion is formed on a physical development nucleus by a development process, and a silver halide emulsion layer is removed by a subsequent washing process to form a metal silver image portion (hereinafter referred to as silver) on an aluminum support. Image portion) is exposed. At the same time, the anodized aluminum surface itself is exposed as a non-image area.

The exposed silver image area and the non-image area are coated with a finishing solution containing a protective colloid such as gum arabic, dextrin, carboxymethylcellulose, polystyrene sulfonic acid and the like for protection. A so-called gumming process is performed. The finishing solution is also called a fixing solution or a finishing solution, and generally contains a compound (for example, a nitrogen-containing heterocyclic compound having a mercapto group or a thione group) that renders a silver image portion lipophilic.

US Pat. No. 5,427,889 discloses that a pit having a diameter of 0.03 to 0.30 μm is formed in 100 μm ^2.
By using an aluminum support having at least 500 per pit and having an average diameter of the pits of from 0.05 to 0.20 μm, it is also possible to use the method described in US Pat.
No. 0 describes that a lithographic printing plate having excellent ink receptivity and printing durability can be obtained by using an aluminum support having a surface area of the recess of 50% or more of the total surface area. I have.

[0009] However, even when these aluminum supports are used, extremely fine physical development nuclei are carried thereon, and as a result of the DTR development with a high pH alkali developing solution, a stable and excellent lithographic printing plate is obtained. There was a problem that a printing plate could not be obtained.

Further, as a general problem of the aluminum lithographic printing plate, there is a problem that the ink detachability at the start of printing is poor. In the field of offset rotary printing presses, etching with dampening solution is often omitted at the start of printing to prevent paper breakage.The dampening solution is fed after ink is applied to the entire surface of the printing plate to remove ink in the non-image area. A printing method of separating is used. In such printing, a delay in the ink desorption speed in the non-image area significantly reduces the printing efficiency.

Further, there is a fingerprint stain as a problem related to the non-image portion. This is a problem in that a fingerprint attached to a non-image portion of a printing plate during handling of a printing plate causes ink to adhere to the printing plate to stain the printing plate.

Another problem related to the silver image portion is fine line reproducibility. This is a problem that a fine line image of about 100 μm or less is not faithfully reproduced on a printed matter.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lithographic printing plate which uses a silver complex salt diffusion transfer method on an aluminum plate as a support and has a remarkably improved ink receptivity and printing durability. Is to provide a way. Another object of the present invention is to further improve the ink detachability and fingerprint smear in the non-image area and to further improve the fine line reproducibility in the silver image area.

[0014]

SUMMARY OF THE INVENTION It is an object of the present invention to expose a lithographic printing plate utilizing a silver complex diffusion transfer method having a physical development nucleus between an anodized aluminum support and a silver halide emulsion layer. Thereafter, at least in a plate-making method of performing development processing, the support has 500 or more pits having a diameter of 0.03 to 0.30 μm per 100 μm ² and an average diameter of the pits is 0.05 to 0.20 μm. An aluminum plate or an aluminum plate in which the surface area of the depression is 50% or more of the total surface area, wherein the plate is treated with a developer containing a dissolution inhibitor of aluminum oxide. Achieved.

Hereinafter, the present invention will be described in detail. One of the aluminum supports used in the present invention is a pit having a diameter of 0.03 to 0.30 μm, described in US Pat. No. 5,427,889, having a diameter of 5 μm per 100 μm ^2.
And the average diameter of those pits is 0.
It is an aluminum support of 0.5 to 0.20 μm. The number of pits having a diameter of 0.03 to 0.30 μm is preferably 10
It is about 1,000 or more per 0 μm ² , and the upper limit is 15,
Up to 000 are preferred. 0.03-0.30 μm in diameter
The average diameter of the pits is preferably 0.05 to 0.15 μm.
m. The pit diameter is a dimension when the diameter of a pit having a shape other than a circle is regarded as a circle. The center depth of this pit is 1/3 of the pit diameter
(0.01-0.1 μm) or more, preferably 好 ま し く
(0.01 to 0.1 μm) to 3 (0.09 to 0.9 μm)
Position m) is preferred. The total projected area of these minute pits is preferably about 5 to 50%.

Another aluminum support used in the present invention is the aluminum support described in US Pat. No. 5,405,730, wherein the surface area of the recess is 50% or more of the total surface area. is there. Such a support is an area of the actual surface on the granulated and anodized side of an aluminum support in which the depressions have a continuous depth of at least 0.5 μm, and the ridges extend continuously to a depth of less than 0.5 μm. Area of the actual surface of the grained and anodized side of the aluminum support having the surface, the depth being measured perpendicular to the theoretical surface, the theoretical surface being the highest point at each sampling length of 0.25 mm Consists of a line connecting the highest point in the adjacent sampling length of the measurement length, the total surface area is equal to the sum of the surface area of the depression and the surface area of the ridge, and the surface area of each of the depression and the ridge is the intersection of the actual surface and the line as a diameter. 0.5 μm below the theoretical surface, equal to the area of a circle having a distance between
Only parallel.

The sum of the surface areas of the depressions is preferably at least 75% of the total surface area, particularly preferably at least 90%. The depth of the recess preferably has a maximum depth of 1 μm, particularly preferably a maximum depth of 2 μm.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the plate making method of the present invention, the aluminum oxide on the aluminum support is subjected to a developing process (the time from immersion in a developing solution in a developing tank to stopping of developing in the next processing step). In order to suppress the amount of dissolution and reduction caused by the process (1), the solution is treated with a developer containing a dissolution inhibitor for aluminum oxide, preferably an alkaline earth metal.

JP-A-63-260491 discloses a DTR
It is described that, as a support for an aluminum lithographic printing plate using the method, it is desirable to increase the ratio of the amount of aluminum oxide to the surface roughness (Ra) in order to prevent etch pits. However, even if the amount of aluminum oxide per unit area is increased by anodizing treatment, the above-mentioned problem of the present invention is not fundamentally solved.

In the present invention, regardless of the amount of aluminum oxide contained in the aluminum support, it is important to suppress the amount of the aluminum oxide which is dissolved and reduced by development. As the aluminum support of the aluminum lithographic printing plate of the present invention, one having 1.5 g or more, preferably 1.8 g to 5 g of porous aluminum oxide per square meter is used.

In the present invention, when the developing treatment (from immersion in the developing solution to the stop of the development in the next processing step) is performed, the amount of aluminum oxide which is dissolved and reduced is 0.6 g / m 2. Below, it is preferable to select a condition such that it is 0.5 g or less, particularly preferably 0.3 g to 0.0 g.

The total amount of aluminum oxide is measured by dissolving aluminum oxide in a dichromic acid solution and measuring according to JIS.
-H-8680-7 "film mass method". In the present invention, the amount of reduction of the aluminum oxide is measured by removing the photosensitive layer of the aluminum lithographic printing material with hot water or the like to form an aluminum support, scraping the aluminum oxide on the back surface, and measuring the total weight (a). Next, the plate is subjected to development and plate making and dried, and the total weight (b) is measured again, and the difference (ab) between the weights is defined as the amount dissolved by the development.

In the plate making method of the present invention, the development processing time (the time from immersion in the developing solution to the stop of development in the next processing step) is not limited, and is, for example, 20 seconds or shorter. After development, an additional 3 to 3
Development for about 0 seconds may be allowed to proceed.

In the present invention, from the viewpoint of suppressing the dissolution of aluminum oxide, it is generally preferable that the pH of the developer is lower, the development temperature is lower, and the development processing time is shorter. Specifically, the pH of the developer
Is usually 10 to 14, but in consideration of printing characteristics, pH
The temperature is preferably in the range of 12.0 to 13.5, the temperature of the developer is preferably about 15 to 30 ° C., and the developing time is 5 to 40 ° C.
Seconds are preferred.

The reduction in the amount of aluminum oxide on the aluminum support can be attained by using alkaline earth metals such as calcium, magnesium, beryllium and barium, using the alkaline earth metals in a washing solution in addition to a developing solution, It is governed by conditions such as the pH of the developer, the development processing time, and the development temperature.

In a preferred embodiment of the present invention, the developer contains an alkaline earth metal. As the alkaline earth metal used in the present invention, calcium, strontium,
Barium, beryllium, magnesium. When an alkaline earth metal is added to the developer, it may be added as the following compound. For example, calcium bromide, calcium carbonate, calcium chloride, calcium citrate, calcium gluconate, calcium hydroxide, calcium iodide, calcium nitrate, calcium nitrite, calcium oxalate, calcium stearate, calcium sulfate, calcium tartrate, chloric acid Barium, barium perchlorate, barium bromide, barium bromate, barium nitrate, barium sulfate, barium thiosulfate, barium nitrite, beryllium chloride, beryllium bromide, beryllium iodide, beryllium nitrate, magnesium chloride, perchloric acid Magnesium, magnesium bromide, magnesium iodide, magnesium sulfate, magnesium nitrate, strontium chloride, strontium bromide, strontium nitrate, strontium sulfate, and the like. These compounds are contained as alkaline earth metals in a developer at a concentration of 1 to 100 mmol / l, preferably 2 to 100 mmol / l, more preferably 3 to 80 mmol / l. Among the above alkaline earth metals, calcium is particularly preferably used.

The developer used in the present invention includes a developing agent such as polyhydroxybenzenes such as hydroquinone, ascorbic acid and its derivatives, 1-phenyl-
3-pyrazolidinones such as 3-pyrazolidinone and derivatives thereof, alkaline substances such as potassium hydroxide, sodium hydroxide, lithium hydroxide, tertiary sodium phosphate, or amine compounds, preservatives such as sodium sulfite, thickeners such as Carboxymethyl cellulose, antifoggants such as potassium bromide, development modifiers such as polyoxyalkylene compounds, chelating agents such as ethylenediaminetetraacetic acid, anionic gelatin flocculants such as polystyrenesulfonic acid and maleic anhydride copolymers, and And an additive such as a silver halide solvent as shown in the following.

Examples of the silver halide solvent include thiosulfates such as sodium thiosulfate and potassium thiosulfate; sulfites such as sodium sulfite and potassium bisulfite;
Iodides, such as potassium iodide and sodium iodide
Examples thereof include 2-mercaptobenzoic acid and its derivatives, cyclic imides such as uracil, alkanolamines, diamines, mesoionic compounds, and thioethers.

Of these silver halide solvents, thiosulfates, alkanolamines, mesoionic compounds and thioether compounds are preferred. The addition amount of thiosulfate is 4 to 50 g, preferably 5 to 50 g per liter of the developing solution.
Approximately 40 g.

As the alkanolamine, for example, 2-alkanolamine
(2-aminoethylamino) ethanolamine, diethanolamine, N-methylethanolamine, triethanolamine, N-ethyldiethanolamine, diisopropanolamine, ethanolamine, 4-aminobutanol, N, N-dimethylethanolamine, 3-amino And propanol, N, N-ethyl-2,2′-iminodiethanol, 2-methylaminoethanol, 2-amino-2-methyl-1-propanol and the like. The amount of addition is 1 to 100 g, preferably 10 to 100 g, per liter of the developer.

The mesoionic compound is disclosed in
No. 328559, No. 9-160248, No. 9-1
No. 71257 is disclosed.
The addition amount of the mesoionic compound varies depending on various conditions, but is 0.1 g to 10 g, preferably 0.1 g to 5 g per liter of the developer.

The thioether compound is disclosed in US Pat.
No. 0,294 and Japanese Patent Application No. 9-89444. The addition amount of the thioether compound is 0.01 g to 20 g, preferably 0.1 g to 10 g per liter of the developer.

Among the above silver halide solvents, it is particularly preferable to use a combination of a thiosulfate and an alkanolamine.

It is preferable that the developer further contains a compound (lipophilic agent) for making the silver image area lipophilic. Examples of oleophilizers include Focal Press, London New York (1972), by Andrelot and Edith Weide, Photographic Silver Halide Diffusion Processes, 105, 10
Compounds described on page 6 can be mentioned. For example, there are a compound having a mercapto group or a thione group and a quaternary ammonium compound. In the present invention, a compound having a mercapto group or a thione group is preferably used. Particularly preferred are nitrogen-containing heterocyclic compounds having a mercapto group or a thione group, and JP-B-48-2972.
No. 3 and JP-A-58-127928.
Specific examples will be described below, but the present invention is not limited thereto.

2-mercapto-4-phenylimidazole, 2-mercapto-1-benzylimidazole, 2-mercapto-1-benzylimidazole
Mercapto-benzimidazole, 1-ethyl-2-mercapto-benzimidazole, 2-mercapto-1-
Butyl-benzimidazole, 1,3-diethyl-benzimidazoline-2-thione, 1,3-dibenzyl-imidazolidin-2-thione, 2,2'-dimercapto-
1,1'-decamethylene-diimidazoline, 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-benzoxazoline-
2-thione, 1-phenyl-3-methylpyrazoline-5
-Thione, 3-mercapto-4-allyl-5-pentadecyl-1,2,4-triazole, 3-mercapto-5
-Nonyl-1,2,4-triazole, 3-mercapto-4-acetamido-5-heptyl-1,2,4-triazole, 3-mercapto-4-amino-5-heptadecyl-1,2,4-triazole , 2-mercapto-5-
Phenyl-1,3,4-thiadiazole, 2-mercapto-5-phenyl-1,3,4-thiadiazole, 2-
Mercapto-5-n-heptyl-oxathiazole, 2
-Mercapto-5-nheptyl-oxadiazole, 2
-Mercapto-5-phenyl-1,3,4-oxadiazole, 2-heptadecyl-5-phenyl-1,3,4
-Oxadiazole, 5-mercapto-1-phenyl-
Tetrazole, 2-mercapto-5-nitropyridine,
1-methyl-quinoline-2 (1H) -thione, 3-mercapto-4-methyl-6-phenyl-pyridazine, 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-
And diphenyl-S-triazolino [1,2-a] -S-triazoline. The amount of these lipophilic agents added to the developer is preferably about 0.01 to 10 g / liter.

In the present invention, a water washing treatment is performed after the development treatment. The washing solution may contain a buffer for buffering the pH in the range of 4 to 8, preferably 4.5 to 7, for example, a phosphate buffer, a citrate buffer or a mixture thereof. Further, a preservative may be contained. The washing solution may further contain proteolytic enzymes (eg, pepsin, rennin, trypsin, chymotrypsin, cathepsin, papain, ficin, thrombin, renin, collagenase, bromelain, bacterial proteinase) and the above-described lipophilic agent. it can.

A neutralization stabilization treatment for stopping the progress of the development may be performed between the development treatment and the water washing treatment, and the lipophilic agent may be contained in the neutralization solution.

The washing solution is used for completely removing the silver halide emulsion layer on the aluminum support.
A method of spraying a washing liquid at 25 to 35 ° C. by a jet method or a method of peeling an emulsion layer with a scrub roller while spraying the washing liquid is generally used.

In the aluminum lithographic printing plate, the removal of the silver halide emulsion layer by washing with water is a very important step for completely exposing the silver image portion and the non-image portion constituted by the aluminum surface itself. In particular, the silver image portion receiving the ink needs to have strong lipophilicity, and it is necessary to completely remove substances that inhibit lipophilicity such as gelatin.

The silver image portion and the non-image portion exposed by the water washing process are subjected to a treatment with a finishing solution in order to increase their lipophilicity and hydrophilicity and to protect the plate surface.
In the present invention, in the finishing solution, for protecting the anodized layer in the non-image area and improving the hydrophilicity, gum arabic, dextrin, sodium alginate, propylene glycol ester of alginic acid, hydroxyethyl starch, carboxymethyl cellulose, hydroxyethyl cellulose,
It is preferable to contain a protective colloid such as polyvinylpyrrolidone, polystyrenesulfonic acid, and polyvinyl alcohol. Further, in order to further improve the lipophilicity of the image area, it is preferable to contain the lipophilic agent. Further, the above enzyme can be contained.

The planographic printing plate of the present invention has a physical development nucleus and a silver halide emulsion layer on an aluminum support. The silver halide emulsion is selected from commonly used silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodobromide, silver iodobromide, etc., but mainly contains silver chloride (50 mol of silver chloride). %). The emulsion type may be either a negative type or a positive type. These silver halide emulsions can be chemically or spectrally sensitized as necessary.

It is preferable to use gelatin as a hydrophilic colloid in the silver halide emulsion layer when preparing silver halide grains. Various gelatins such as acid-treated gelatin and alkali-treated gelatin can be used as the gelatin.
Further, those modified gelatins (for example, phthalated gelatin, amidated gelatin, etc.) can also be used. Further, hydrophilic polymer compounds such as polyvinylpyrrolidone, various starches, albumin, polyvinyl alcohol, gum arabic, and hydroxyethyl cellulose can be contained. As the hydrophilic colloid to be used, it is desirable to use a hydrophilic colloid layer substantially free of a hardener in order to facilitate the peelability after development.

The emulsion layer of the lithographic printing plate according to the present invention may optionally contain an anion, a cation, a betaine, a nonionic surfactant, a thickener such as carboxymethyl cellulose, a coating aid such as an antifoaming agent, etc. A chelating agent such as ethylenediaminetetraacetate and a developing agent such as hydroquinone, polyhydroxybenzenes and 3-pyrazolidinones may be contained.

The aluminum support used in the present invention is a roughened and anodized aluminum plate, preferably the one described in US Pat. No. 5,427,889.

The physical development nuclei of the physical development nucleus layer used in the present invention may be those used in a known silver complex salt diffusion transfer method. For example, colloids such as gold and silver, and water-soluble salts such as palladium and zinc are used. Metal sulfide mixed with sulfide can be used. Various hydrophilic colloids can be used as the protective colloid. For details and manufacturing method,
For example, JP-B-48-30562 and JP-A-48-55
Nos. 402 and 53-21602, Focal Press, New York, London (1972), by Andrelot and Edith Weide, "Photographic Silver Halide Diffusion Processes".

In the present invention, a water-swellable intermediate layer described in JP-A-3-116151 and a hydrophobic polymer described in JP-A-4-282295 are provided between a physical development nucleus layer and a silver halide emulsion layer. An intermediate layer containing beads may be provided.

[0047]

EXAMPLES The present invention will be described below with reference to examples. Example 1 The electrolytic surface roughening treatment and anodizing of an aluminum support were carried out according to the method described in U.S. Pat. No. 5,427,889 on a plate having an average diameter of about 5 [mu] m.
A 0.30 mm thick aluminum plate having about 700 pits of 0.30 μm per 100 μm ² and an average diameter of these pits of 0.27 μm was obtained. This aluminum plate was anodized after the surface roughening treatment, had 2.7 g of porous aluminum oxide per square meter, and had an average roughness (Ra) of 0.4 to 0.5 μm ( Support A).

According to the support A, the average diameter is about 5 μm.
0.35 mm thick having about 5,600 pits with a diameter of 0.03 to 0.30 μm per 100 μm ² on the plate and having an average diameter of 0.08 μm for these pits
Was obtained. This aluminum plate was anodized after the surface roughening treatment.
7 g of porous aluminum oxide, having an average roughness (R
a) was 0.5 to 0.6 μm (Support B).

A palladium sulfide nucleus solution was applied to these aluminum supports and then dried. The amount of nuclei contained in the physical development nucleus layer was 3 mg / m ² .

A silver halide emulsion was prepared by using alkali-treated gelatin as a protective colloid, and adding potassium hexachloroiridate (IV) having an average particle size of 0.2 μm to the solution by a control double jet method in an amount of 0.001 mol / mol of silver.
A silver bromochloroiodide emulsion containing 15 mol% of silver bromide and 0.4 mol% of silver iodide doped with 6 mmol was prepared. afterwards,
The emulsion was flocculated and washed. Further, after this emulsion was subjected to sulfur gold sensitization, a stabilizer was added, and spectral sensitization was performed using 3 mg of a red-sensitive sensitizing dye per 1 g of silver.

A surfactant was added to the silver halide emulsion thus prepared to prepare a coating solution. The emulsion layer coating solution was coated on the aluminum support coated with the physical development nuclei and dried so that the amount of silver was 2 g / m ² and the amount of gelatin was 2.5 g / m ² to obtain a lithographic printing material sample. Was.

A 633 nm red LD was used for the lithographic printing material.
An image was output by an output device using a laser as a light source, and then processed by a plate-making processor (SLT-85N automatic developing machine manufactured by DuPont) to prepare a lithographic printing plate. The plate making processor includes a developing step (immersion at 22 ° C. for 15 seconds), a washing step (washing out the emulsion layer with a scrub roller while spraying a washing liquid at 35 ° C. for 10 seconds),
It comprises a finishing process (shown at 21 ° C. for 5 seconds) and a drying process.

The developing solutions A and B having the following compositions were used. <Developer A> Sodium hydroxide 25 g Polystyrene sulfonic acid / maleic anhydride copolymer (average molecular weight 500,000) 10 g Sodium ethylenediaminetetraacetate 2 g Sodium sulfite anhydrous 100 g Monomethylethanolamine 50 g 2-Mercapto-5-nheptyl-oxa Diazole 0.5 g Sodium thiosulfate (pentahydrate) 8 g Hydroquinone 15 g 1-phenyl-3-pyrazolidinone 3 g Make up to 1000 ml with deionized water. pH (25 ° C.) = 13.1

<Developer B> Sodium hydroxide 25 g Polystyrene sulfonic acid / maleic anhydride copolymer (average molecular weight 500,000) 10 g Ethylenediaminetetraacetic acid sodium salt 2 g Anhydrous sodium sulfite 100 g Monomethylethanolamine 50 g 2-mercapto-5-n Heptyl-oxadiazole 0.5 g Sodium thiosulfate (pentahydrate) 8 g Hydroquinone 15 g 1-Phenyl-3-pyrazolidinone 3 g Calcium sulfate 22 mmol Aminotri (methylenephosphonic acid) 10 g Make up to 1000 ml with deionized water. pH (25 ° C.) = 13.1

The compositions of the washing solution and the finishing solution used are shown below. <Washing solution> 2-mercapto-5-nheptyl-oxadiazole 0.5 g monoethanolamine 13 g sodium bisulfite 10 g proteinase 1 g Water is added to adjust the total amount to 1000 cc. The pH was adjusted to 6.0. Bioprolase AL-15 as a proteolytic enzyme
(Bacterial proteinase, manufactured by Nagase & Co., Ltd.) was used.

<Finishing solution> Phosphoric acid 0.5 g Monoethanolamine 5.0 g 2-Mercapto-5-n-butyloxyoxasole 0.5 g Polyglycerol (hexamer) 50 g Make up to 1000 ml with deionized water. The pH was adjusted to 7.2.

When the lithographic printing materials A and B were developed using the developing solution A or B, the reduction amount of aluminum oxide per square meter of the developing solution A was 1.0 g. B was 0.3 g.

The lithographic printing plate produced using this developer A or B was subjected to a printing press Heidelberg TOK (He
Printing was performed using idelberg's offset printing press trademark), ink (New Champion Boku H, manufactured by Dainippon Ink and Chemicals, Inc.), and a commercially available PS plate humidifier, and the printing durability was evaluated. As a result, about 20,000 printing plates AA made with the combination of developer A and material A, about 70,000 sheets of printing plate AB made with developer A-material B, and About 100,000 printing plates B-A were prepared in A, but the developer B-
The printing plate BB made with the material B had a printing durability sufficiently exceeding 100,000 sheets.

The four types of lithographic printing plates described above were evaluated for ink release properties. The ink detachability was evaluated by attaching the printing plate to an offset rotary printing press, placing the ink on the plate surface, sending a fountain solution, and measuring the number of sheets until the ink stain on the non-image area was removed. . As a result, the printing plates AA and AB
Were about 100 sheets and the printing plate BA was 40 sheets,
There were 10 printing plates BB.

Further, the four types of lithographic printing plates were evaluated for fingerprint smear. After forcibly pressing a finger against a non-image portion of the printing plate to apply a fingerprint, the printing plate left for one day is printed on a printing press Heidelberg TOK (a trademark of an offset printing press manufactured by Heidelberg), ink (Dai Nippon Ink Co., Ltd.) Printing was performed using a new champion black ink H) manufactured by the company) and a commercially available humidifying solution for PS plates, and fingerprint smearing was evaluated. As a result, the printing plate A-
In both A and AB, a clear fingerprint stain occurred on the non-image portion of the printed matter printed, and the print plate BA slightly stained the fingerprint, but the printing plate BB showed no fingerprint stain at all. Was.

Next, the fine line reproducibility of the lithographic printing plate prepared using the developing solution A or B was tested by the following method. Registration marks (register marks consisting of 80 μm thin lines) for registration at the four corners of the printing plate with a red LD laser output machine
Was output simultaneously with the image output. When these printing plates were similarly printed using a printing machine Heidelberg TOK, the printing plates AA and AB did not have the register marks printed on the printed matter, and the printing plate BA had slightly the register marks printed. However, register marks could be clearly reproduced on the printing plate BB.

Example 2 In accordance with Example 1 of US Pat. No. 5,405,730, an aluminum support having a concave surface area of 90% or more of the total surface area was prepared. A lithographic printing material was prepared according to Example 1 described above, and the plate was similarly prepared using the developing solutions A and B of Example 1 and tested. A clear significant difference was observed between the developer A and the developer B in the same manner as in Example 1, in which the developer B was superior in all the test items.

[0063]

By using the plate making method of the present invention, the printing durability is improved, and the ink detachability and fingerprint smear of the non-image area and the reproducibility of the fine line of the silver image area are greatly improved. In particular, when calcium is contained in the developer, a remarkable effect is obtained.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2H025 AA00 AA02 AA04 AA12 AB03 AC01 AD01 BB00 DA14 DA20 DA36 FA16 2H096 AA09 BA17 CA03 EA02 GA10

Claims (2)

[Claims] 1. A plate-making method comprising: exposing a lithographic printing plate utilizing a silver complex salt diffusion transfer method having a physical development nucleus between an anodized aluminum support and a silver halide emulsion layer; The support has a diameter of 0.03-
It has more than 500 0.30 μm pits per 100 μm ² and the average diameter of the pits is 0 m ² . 05 to 0.
A plate making method for a lithographic printing plate, which is an aluminum plate having a thickness of 20 μm and is treated with a developer containing a dissolution inhibitor for aluminum oxide. 2. A plate-making method comprising: exposing a lithographic printing plate utilizing a silver complex salt diffusion transfer method having a physical development nucleus between an anodized aluminum support and a silver halide emulsion layer; A method of making a lithographic printing plate, wherein the support is an aluminum plate having a surface area of the recess of 50% or more of the total surface area, and is treated with a developer containing a dissolution inhibitor of aluminum oxide.