JPH11180064A - Manufacture of lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high ink receiving property stably and raise an antiprinting property by containing a water soluble iodide in at least one treatment liquid after development. SOLUTION: A lithographic printing material having a physical development cell nucleus between an aluminum carrier and a silver halide emulsion layer is processed in use of treatment liquid containing a lipophilic agent for silver images, and in this instance, a water soluble iodide is contained in at least one treatment liquid after development. Such a water soluble iodide can include for use lithium, potassium, sodium, ammonium, or the like, and it is contained in at least one liquid among treatment liquid except development liquid, viz., water washing liquid, finishing liquid, and further stabilizing liquid, etching liquid or the like furnished as required. Also, such a lipophilic agent is contained in at least one liquid among development liquid, water washing liquid, and further stabilizing liquid, etching liquid, or the like before printing provided as required. This can attain a high ink receiving property and improve antiprinting property.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for making a lithographic printing plate utilizing a silver complex salt diffusion transfer method using an aluminum plate as a support.

[0002]

2. Description of the Related Art A planographic 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 mono-sheet type lithographic printing plate utilizing a silver complex salt diffusion transfer method using an aluminum plate as a support (hereinafter referred to as an aluminum lithographic printing plate) is disclosed in
No. 118244, No. 57-158844, No. 63-2
60491, JP-A-3-116151, 4-28
No. 2,295, U.S. Pat. Nos. 4,567,131 and 5,427,889.

[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 comprises 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 or the like for protection. The so-called processing is performed. It is also known that this finishing liquid contains a compound (hereinafter, referred to as an oleophilic agent) that makes a silver image portion lipophilic.

The problems in the plate making method of the aluminum lithographic printing plate are that the silver image portion at the start of printing has poor ink acceptability and insufficient printing durability. This is largely attributable to the insufficiency of the mechanism of the plate making process, particularly the removal of the silver halide emulsion layer (gelatin). Regarding the above problem of ink acceptability, it is disclosed in Japanese Patent Application Laid-Open No. 4-306660 that a lipophilic agent is contained in the finishing liquid.
No. 7-77805, U.S. Pat. No. 4,567,1.
No. 31, for example. It is also described in the above-mentioned patent publications that the developer contains an oleophilic agent.

The use of a lipophilic agent improves ink receptivity to a certain extent, but the ink receptivity may be insufficient depending on changes in printing conditions, for example, changes in the type of printing press or ink. A stable and high ink receptivity has not yet been obtained. Therefore, further improvements are desired. Regarding the problem of printing durability, desired performance has not been obtained, and improvement is desired.

Another problem in the method of making an aluminum lithographic printing plate is that the washing liquid becomes cloudy.
This turbidity is caused by the silver complex salt (silver ion) generated during the development being brought into the washing solution. In the aluminum lithographic printing plate, the substantially uncured silver halide emulsion layer has a very large swelling, so that the emulsion layer absorbs a large amount of liquid and the silver complex salt which is not trapped by physical development nuclei is brought into the washing liquid. Seems to have increased.

In general, gelatin or chemically developed silver or the like dissolved or dispersed in a washing solution is recovered from the washing solution by a filter, and the washing solution passed through the filter is generally circulated and reused. . However, silver complexes cannot be recovered by filtration filters. Moreover,
Disposal of the processing solution containing the silver complex has environmental problems, and countermeasures are desired.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of making an aluminum lithographic printing plate which is stable and has high ink acceptability and excellent printing durability. Another object of the present invention is to provide a plate making method that prevents the washing solution from becoming cloudy and has no environmental problems.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lithographic printing material having a physical development nucleus between an aluminum support and a silver halide emulsion layer. A plate making method using a lithographic printing plate is characterized in that at least one processing solution after development contains a water-soluble iodide.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The lipophilic agent used in the present invention comprises:
Preferred are compounds having a mercapto group or a thione group, for example, JP-B-48-29723 and JP-A-58-1983.
What is described in -127829 is used preferably.

The water-soluble iodide used in the present invention includes water-soluble iodides such as lithium, potassium, sodium and ammonium, but may be an organic compound of iodide.

In the present invention, the oleophilic agent is at least one of a developing solution, a washing solution, a finishing solution, and a stabilizing solution (neutralizing solution after development) or an etching solution before printing, if necessary. It is contained in the processing solution. Further, the water-soluble iodide is a processing solution other than the developing solution, that is, a washing solution, a finishing solution,
Further, it is contained in at least one processing solution such as a stabilizing solution or an etchant provided as needed. It is preferable that the lipophilic agent and the water-soluble iodide are contained in the same processing solution, and it is particularly preferable that they are contained together in the processing solution following development.

When the water-washing liquid contains a lipophilic agent and a water-soluble iodide, the water-washing liquid is prevented from becoming cloudy, silver can be recovered, and at the same time, the ink receptivity and the printing durability are further improved.

The content of the water-soluble iodide is 0.001 to 0.2 mol, preferably 0.005 per liter of the processing solution.
~ 0.1 mol.

As the lipophilic agent, a nitrogen-containing heterocyclic compound having a mercapto group or a thione group is preferable, and examples thereof include those having a general formula shown in the following chemical formula 1.

[0020]

Embedded image

(Wherein R ₁ and R ₃ are an alkyl group, alkenyl group, aralkyl group or aryl group having 3 or more carbon atoms, preferably 3 to 12 carbon atoms, and R ₂ is a hydrogen, an alkyl group, an alkenyl group or an aralkyl group). Or an aryl group.
n represents an integer of 1 or more. When R ₂ is an alkyl group, alkenyl group, aralkyl group or aryl group having 3 or more carbon atoms, n may be 0. Z is N in the formula,
The remaining atomic groups of the bond necessary to form a 5- or 6-membered ring with C are shown. )

Specific examples of the 5- or 6-membered ring include imidazole, imidazoline, thiazole, thiazoline,
Oxazole, oxazoline, pyrazoline, triazole, thiadiazole, oxadiazole, tetrazole, pyridine, pyrimidine, pyridazine, pyrazine, triazine, etc., and these rings may be two or more condensed rings; And those condensed with a naphthalene ring. Further, it is preferable that the compound does not have a water-soluble group such as a carboxy group and a sulfo group.

Specific examples of such compounds include 2-mercapto-4-phenylimidazole and 2-mercapto-1
-Benzylimidazole, 2-mercapto-1-butyl-benzimidazole, 1,3-dibenzyl-imidazolidin-2-thione, 2-mercapto-4-phenylthiazole, 3-butyl-benzothiazoline-2-thione, 3- Dodecyl-benzothiazoline-2-thione, 2
-Mercapto-4,5-diphenyloxazole, 3-
Pentyl-benzoxazoline-2-thione, 1-phenyl-3-methylpyrazolin-5-thione, 3-mercapto-4-allyl-5-pentadecyl-1,2,4-triazole, 3-mercapto-5-nonyl-1 , 2,4
-Triazole, 3-mercapto-4-acetamide-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-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, 3-mercapto-4-methyl-6-phenyl-pyridazine, 2-mercapto-5,6-diphenyl-pyrazine, -Mercapto-4,6-diphenyl-1,3,5-triazine, 2-
Amino-4-mercapto-6-benzyl-1,3,5-
Examples include, but are not limited to, triazines.

The content of the compound having a mercapto group or a thione group is 0.01 to 1 per liter of the processing solution.
About 10 g is appropriate.

In order to further improve ink receptivity and printing durability, the compound having a mercapto group or a thione group is preferably contained in two or more processing solutions. Preferably, it is contained in three processing solutions of a developing solution, a washing solution and a finishing solution. Further, a compound having a mercapto group or a thione group can be contained in the lithographic printing material.

The compound having a mercapto group or a thione group is dissolved in an alkaline solution, but is not dissolved in a neutral to weakly acidic washing solution. Therefore, an organic solvent, an amine compound (for example, amino alcohol), polyethylene glycol, It can be added using a dissolution aid such as a quaternary ammonium salt type cationic surfactant.

In the present invention, the protease is preferably contained in the washing solution and / or the finishing solution.
As a protease, a known vegetable or animal enzyme capable of hydrolyzing proteins such as gelatin is used. For example, pepsin, rennin, trypsin, chymotrypsin, cathepsin, papain, ficin, thrombin, renin, collagenase, bromelain, bacterial proteinase (for example, bioprase manufactured by Nagase & Co., Ltd.) and the like can be mentioned. Among these, trypsin, papain, ficin, and bacterial proteinase are particularly preferred. The content of the enzyme in the washing solution and / or the finishing solution is suitably about 0.5 to 50 g / liter.

In the present invention, the pH of the washing solution is 4 to 4.
8, preferably a buffer to buffer in the range of 4.5 to 7,
For example, it may contain a phosphate buffer, a citrate buffer or a mixture thereof. Further, a preservative may be contained.

The above-mentioned washing solution is used for completely removing the silver halide emulsion layer on the aluminum support.
Usually, a method of spraying a washing liquid at 25 to 35 ° C. by a jet method or a method of peeling the emulsion layer with a scrub roller while spraying the washing liquid is adopted. The emulsion layer peeled off from the aluminum support is dissolved or dispersed in the washing solution, and once returned to a tank for storing the washing solution,
It is collected by the filter by being circulated through a filtration filter arranged outside the system.

In the aluminum lithographic printing plate, the washing and removal of the silver halide emulsion layer 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 developer used in the present invention includes a developing agent such as polyhydroxybenzenes, 3-pyrazolidinones, and alkaline substances such as potassium hydroxide, sodium hydroxide, lithium hydroxide, tertiary sodium phosphate, and amines. Compounds, preservatives such as sodium sulfite, thickeners such as carboxymethylcellulose, antifoggants such as potassium bromide, development modifiers such as polyoxyalkylene compounds, silver halide solvents such as thiosulfate, thiocyanate , Cyclic imide, thiosalicylic acid, mesoionic compounds and the like. The pH of the developer is usually 10 to 14, preferably 1 to 14.
2-14.

The silver image portion and the non-image portion exposed by the developing process and the rinsing process are treated with a finishing solution in order to increase their lipophilicity and hydrophilicity and to protect the plate surface. For example, in order to protect the anodized layer in the non-image area and improve the hydrophilicity, gum arabic, dextrin, sodium alginate, propylene glycol ester of alginic acid, hydroxyethyl starch, carboxymethylcellulose, hydroxyethylcellulose, polyvinylpyrrolidone, polystyrenesulfonic acid, polyvinyl It is preferable to contain a protective colloid such as alcohol.

The lithographic 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.

The silver halide emulsion layer may contain the compound having a mercapto group or a thione group.
Gelatin is preferably used as the 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.) or low molecular weight gelatin having an average molecular weight of 70,000 or less 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 aluminum support used in the present invention is a roughened and anodized aluminum plate, for example, the one described in US Pat. No. 5,427,889 is used.

The physical development nucleus of the physical development nucleus layer used in the present invention may be a physical development nucleus used in a known silver complex salt diffusion transfer method, for example, a colloid such as gold or silver, or a water-soluble salt such as palladium or zinc. 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, Focal Press, London New York (1972), Andre Lott and Edith
See Weide, "Photographic Silver Halide Diffusion Processes".

In the present invention, between the physical development nucleus layer and the silver halide emulsion layer, JP-A-3-116151,
A water-swellable intermediate layer described in JP-A-282295 and JP-A-8-234437 may be provided.

[0038]

EXAMPLES The present invention will be described below with reference to examples.

Example 1 The electrolytic surface roughening treatment and anodic oxidation of an aluminum support were carried out according to the method described in US Pat. No. 5,427,889 on a plateau having an average diameter of about 5 μm.
0.30 μm pits are about 5,600 per 100 μm ²
And the average diameter of these pits is 0.08 μm
Was obtained as an aluminum plate having a thickness of 0.30 mm. This aluminum plate was anodized after the surface roughening treatment, and had an average roughness (Ra) of 0.5 to 0.6 μm.

The aluminum support was coated with a physical development nucleus solution composed of a silver sol prepared by the Curey Lea method, and then dried. The amount of silver contained in the physical development nucleus layer was 3 mg / m ² .

As a silver halide emulsion, alkali-treated gelatin was used as a protective colloid, and potassium hexachloroiridate (IV) having an average particle size of 0.2 μm was added in an amount of 0.006 m per mol of silver by a control double jet method.
A mol-doped silver chloroiodobromide emulsion (AgBr 10 mol%, AgI 0.4 mol%) was prepared. Further, this emulsion was subjected to sulfur gold sensitization and spectral sensitization using a sensitizing dye for red LD.

A surfactant is added to the silver halide emulsion thus prepared, and coated on the aluminum support coated with the physical development nucleus so that the silver amount becomes 2 g / m ² .
After drying, a lithographic printing material was obtained.

The above lithographic printing material was converted to a red LD of 633 nm.
An image was output by an output machine using a laser as a light source, and then processed by a plate-making processor (SLT-N automatic developing machine manufactured by DuPont) to prepare a lithographic printing plate. The plate making processor includes a developing step (immersion at 21 ° C. for 30 seconds), a washing step (peeling the emulsion layer with a scrub roller while vigorously shower-spraying a washing liquid at 33 ° C. for 10 seconds), and a finishing step (21 C., 5 seconds shower) and a drying step.

The washing step includes a tank for storing 30 liters of washing liquid, a unit for supplying the lithographic printing material from the tank to the lithographic printing material via a pump to peel off and remove the emulsion layer, and a washing filter for removing the emulsion layer from the tank. Is circulated. As the filtration filter, a cylindrical 5 μm filter was used.

The turbidity of the washing solution was observed after a 100 m ² treatment using the following developing solution, washing solution and finishing solution.

<Developer A> Sodium ethylenediaminetetraacetate 5 g Sodium hydroxide 20 g Hydroquinone 20 g 1-Phenyl-3-pyrazolidinone 2 g Anhydrous sodium sulfite 80 g Monomethylethanolamine 10 g Anhydrous sodium thiosulfate 6 g Polyethylene glycol (average molecular weight 400) 10 g Water In addition, adjust the total amount to 1000cc. The pH was adjusted to 13.0.

<Washing solution A> 10 g of sodium bisulfite 40 g of potassium monophosphate 3 g of potassium iodide Water is added to adjust the total amount to 1000 cc. The pH was adjusted to 6.0.

<Washing liquid B> 2-Mercapto-5-n-heptyl-oxadiazole 0.5 g Triethanolamine 13 g Sodium bisulfite 10 g Potassium monophosphate 40 g Water is added to adjust the total amount to 1000 cc. The pH was adjusted to 6.0.

<Washing solution C> 2-mercapto-5-n-heptyl-oxadiazole 0.5 g triethanolamine 13 g sodium bisulfite 10 g potassium monophosphate 40 g potassium iodide 3 g Water was added to adjust the total amount to 1000 cc. I do. The pH was adjusted to 6.0.

<Finishing liquid A> 10 g of gum arabic 10 g of sodium phosphate monobasic The total amount is adjusted to 1000 cc by adding water. The pH was adjusted to 6.0.

As a result of the above treatment, the washing solution A was significantly clouded, and the washing solution B was slightly clouded, whereas the washing solution C was not clouded at all. Further, with respect to the lithographic printing plate prepared by the above-described method, printing conditions relatively poor in ink acceptability obtained empirically, that is, a printing press Heidelberg T
Printing was performed using OK (a trademark of an offset printing machine manufactured by Heidelberg), ink (New Champion Boku H, manufactured by Dainippon Ink and Chemicals Co., Ltd.), and a commercially available humidifying solution for PS plates. Ride) was evaluated. The ink acceptability was evaluated by the number of sheets after the start of printing until the change in image density did not occur.

As a result, the lithographic printing plate treated with the rinsing liquid A did not get ink even after printing 50 sheets, and the lithographic printing plate treated with the rinsing liquid B showed an ink acceptability of 40 sheets from the start of printing. On the other hand, in the lithographic printing plate treated with the washing liquid C of the present invention, the ink stably stuck on 20 sheets from the start of printing.

Example 2 The developer A used in Example 1 was replaced with 2-mercapto-5-n-
Developer B containing 0.5 g of heptyl-oxadiazole
The procedure was as in Example 1, except that as a result,
The lithographic printing plate treated with the washing solution B showed an ink receptivity of 30 sheets. On the other hand, the lithographic printing plate treated with the rinsing liquid A stuck 20 inks from the start of printing, and the lithographic printing plate treated with the rinsing liquid C stuck 15 inks from the start of printing.

Example 3 Instead of 2-mercapto-5-nheptyl-oxadiazole of the washing solution C of Example 1, 3-mercapto-5-
The test was conducted in the same manner as in Example 1 except that the washing solution D to which nonyl-1,2,4-triazole was added and the washing solution E to which 3-pentylbenzoxazoline-2-thione was added. As a result, no turbidity of the washing liquids D and E was observed. In addition, the same ink receptivity as that of the washing liquid C was obtained.

Example 4 2-Mercapto-5-n was added to the finishing solution A used in Example 1.
Processing was carried out according to Example 1 using finishing solution B containing 1 g of heptyl-oxadiazole and 26 g of triethanolamine and developing solution B of Example 2.

The lithographic printing plate prepared by the above-described method was evaluated for ink receptivity and printing durability according to the method of Example 1. The printing durability was evaluated by the number of printed sheets when printing became impossible due to the lack of a minute halftone dot image portion. As a result, the lithographic printing plate treated with the washing liquid B had a printing durability of 100,000 or less and an ink receptivity of 25. On the other hand, the lithographic printing plate treated with the washing liquid A has a printing durability of 100,000 sheets or more, and ink is applied on 15 sheets from the start of printing, and the lithographic printing plate treated with the washing liquid C has a printing resistance of 100,000 sheets or more. The ink stably applied on 10 sheets from the start of printing with force.

Example 5 A finishing solution C was prepared by adding 2 g of bioprolase AL-15 (bacterial proteinase, manufactured by Nagase & Co., Ltd.) as a protease to the finishing solution B of Example 4. Processing was carried out using the above-mentioned developer B, washing liquid C and finishing liquid C.
As a result, the printing durability was 100,000 sheets or more, and the ink receptivity was 6
It was a sheet.

Example 6 A finishing solution D was prepared by adding 4 g of potassium iodide to the finishing solution A of Example 4. The processing was carried out using the developer B, the washing liquid B and the finishing liquid D of Example 4. As a result, the printing durability was 100,000 sheets or more, and the ink receptivity was 15 sheets.

[0059]

According to the present invention, high ink acceptability and high printing durability can be stably obtained. Further, it is possible to prevent the turbidity of the washing liquid and to provide a plate-making method having no environmental problems.

Continued on the front page (72) Inventor Yoshito Ohashi 3-4-2, Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Paper Mills Co., Ltd.

Claims (3)

[Claims] 1. A method for making a lithographic printing material having a physical development nucleus between an aluminum support and a silver halide emulsion layer using a processing solution containing a lipophilic agent for a silver image, comprising: A method of making a lithographic printing plate, wherein one processing solution contains a water-soluble iodide. 2. The plate making method according to claim 1, wherein at least two processing liquids contain a lipophilic agent for a silver image. 3. The plate-making method according to claim 1, wherein the processing solution is a combination of a water-soluble iodide and a lipophilic agent.