JPH11119442A - Finishing liquid for lithographic printing plate and plate making method - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a finishing liquid for a DTR lithographic printing plate using an aluminum plate having excellent ink release properties as a support. In particular, it is an object of the present invention to provide a finishing liquid in which the ink releasability is improved without lowering the ink receptivity of a silver image portion, and a plate making method using the same. (1) A finishing solution for a lithographic printing plate utilizing a silver complex salt diffusion transfer using an aluminum plate as a support,
(2) a silver complex salt diffusion transfer method having a physical development nucleus between an aluminum support and a silver halide emulsion layer; In the plate making method of exposing the used lithographic printing material to at least a developing treatment, a rinsing treatment and a finishing treatment, a plate making method of a lithographic printing plate wherein the finishing liquid used in the finishing treatment is the finishing liquid of the above (1),

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[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.

[0004] A mono-sheet type lithographic printing plate utilizing a silver complex salt diffusion transfer method using an aluminum plate as a support of the present invention (hereinafter referred to as an aluminum lithographic printing plate)
Are described in JP-A-57-118244 and 57-15884.
No. 4, No. 63-260491, JP-A-3-11615
1, No. 4-282295, U.S. Pat. No. 4,567,
Nos. 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.

As a problem of the above aluminum lithographic printing plate, there is a problem that ink releasability 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.

It is known that the lithographic printing plate finishing liquid to which the present invention is directed contains a water-soluble protective colloid as described above. However, these finishing liquids do not sufficiently improve the ink detachability, and the ink acceptability of the silver image portion is reduced even if the ink detachability is relatively effective. was there.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a DTR using an aluminum plate as a support having excellent ink release properties.
It is to provide a finishing liquid for a lithographic printing plate. In particular, it is an object of the present invention to provide a finishing liquid in which the ink releasability is improved without lowering the ink receptivity of a silver image portion, and a plate making method using the same.

[0011]

The above objects of the present invention are as follows.
(1) A finishing solution for a lithographic printing plate utilizing a silver complex salt diffusion transfer using an aluminum plate as a support, wherein the finishing solution contains a saccharide having a component having a degree of polymerization of 20 or less and 50% by weight or more. (2) a finishing solution further containing at least one of glycerol, polyglycerol and polyethylene glycol having 2 to 20 ethyleneoxy units, (3) an aluminum support and a silver halide emulsion layer After exposing a lithographic printing material utilizing a silver complex salt diffusion transfer method having a physical development nucleus during exposure, at least a developing process, a washing process, and a finishing process, the finishing solution used in the finishing process is (1) ) Or (2), wherein the lithographic printing plate is a finishing solution.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The saccharide used in the present invention is a saccharide having a polymerization degree of 20 or less obtained by hydrolyzing a carbohydrate as a main component. Conventionally, polysaccharides such as gum arabic, starch, dextrin, dextran, and carboxymethyl cellulose, which are known to be used in finishing solutions, are required to have sufficient film-forming properties from the standpoint of plate surface protection, and have a molecular weight of Tens of thousands to hundreds of thousands were common.

In the presensitized plate (PS plate) using a photosensitive resin, the use of the above-mentioned high molecular polysaccharides did not cause any problem. However, in the lithographic printing plate targeted by the present invention,
This has caused a problem of a reduction in the ink desorption speed when applied to a rotary printing press. In particular, there remains a difficult problem in compatibility with the ink acceptability of the image area. The present inventors have conducted intensive studies to solve the above problems, and as a result, have found that saccharides having a polymerization degree of 20 or less as a main component as described above have excellent effects.

The saccharide used in the present invention is preferably a saccharide containing 50% by weight or more of a component having a degree of polymerization of 15 or less, more preferably 50% by weight of a component having a degree of polymerization of 10 or less.
The saccharides contained above. More preferably, it is a saccharide containing a component having a degree of polymerization of 10 or less at 80% by weight or more. The saccharide used in the present invention may be a single component of monosaccharides or oligosaccharides (2 to 6 saccharides), but is usually used as a mixture mainly composed of monosaccharides and oligosaccharides.

Examples of the saccharide used in the present invention include maltose (maltose) obtained by enzymatic degradation of starch, and reduced maltose starch syrup mainly containing maltitol obtained by reducing maltose. These can be obtained from Hayashibara Shoji Co., Ltd., with reduced syrup amamil, HS-40, reduced maltose syrup candy, malbit C, maltodextrin (Sundec #
150, # 180) and the like are commercially available and can be obtained. The amount of the saccharide used is about 10 to 200 g, preferably 20 to 100 g, per liter of the finishing solution.

In the present invention, the finishing liquid preferably further contains at least one of glycerol, polyglycerol and polyethylene glycol having 2 to 20 ethyleneoxy groups. In combination with the above saccharides, the ink detachability is further improved. The polyethylene glycol has an ethyleneoxy group unit of 5 to 15;
Are preferred. The polyglycerol is represented by the following general formula.

[0017]

Embedded image In the formula, n represents an integer of 2 or more. Preferably n is 2-3
0, more preferably n is 3 to 15.

The appropriate amount of glycerol, polyglycerol and polyethylene glycol to be added to the finishing solution is about 10 to 100 g per liter of the finishing solution. The above glycerol, polyglycerol and polyethylene glycol may be used in combination, in which case the amount used is 1 in total.
A range from 0 to 100 g is preferred.

The finishing solution of the present invention may further include protective colloids such as gum arabic, dextrin, sodium alginate, propylene glycol ester of alginic acid, hydroxyethyl starch, carboxymethylcellulose, hydroxyethylcellulose, polyvinylpyrrolidone, polystyrenesulfonic acid, and polyvinyl alcohol. Buffers that buffer the pH in the range of 4 to 8, such as phosphate buffers, citrate buffers, or mixtures thereof, can be included. Further, a preservative may be contained. It is preferable that the finishing liquid further contains a protease.

Proteolytic enzymes are vegetable or animal enzymes capable of hydrolyzing proteins such as gelatin.
Known ones are 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 finishing solution is
About 0.2 to 20 g / liter is appropriate.

It is preferable that the finishing liquid further contains a compound (lipophilic agent) for making the silver image area lipophilic. Examples of lipophilic agents include Focal Press, London New York (1972), by Andrelot and Edith Weide, Photographic Silver Halide Diffusion Processes, 105, 1
Compounds described on page 06 are 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,
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 addition amount of the lipophilic agent to the finishing liquid is 0.0
About 1 to 10 g / liter is appropriate.

The above-mentioned compound having a mercapto group or a thione group is soluble in an alkaline solution, but is not soluble in a neutral to weakly acidic finishing 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.

The developing solution used in the present invention includes developing agents such as polyhydroxybenzenes, 3-pyrazolidinones, and alkaline substances such as potassium hydroxide, sodium hydroxide, lithium hydroxide, and tertiary sodium phosphate.
Alternatively, amine 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 and thiocyanate Additives such as acid salts, cyclic imides, thiosalicylic acid, and mesoionic compounds can be included. The lipophilic agent may be contained. P of developer
H is usually from 10 to 14, preferably from 12 to 14.

The washing solution used in the present invention has a pH of 4
-8, preferably 4.5-7, such as a phosphate buffer, a citrate buffer or a mixture thereof. Further, a preservative may be contained. It is preferable that the washing solution further contains the above protease and a lipophilic agent.

The 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 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.

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.) 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 of the present invention may optionally contain an anion, a cation, a betaine, a nonionic surfactant, a thickener such as carboxymethylcellulose, a coating aid such as a defoamer, 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 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, 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.

[0034]

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.
0.35 μm pits of about 5,60 per 100 μm ²
0 pits and the average diameter of these pits is 0.08μ
m of an aluminum plate having a thickness of 0.30 mm was obtained. This aluminum plate is anodized after roughening treatment.
The average roughness (Ra) was 0.5 to 0.6 μm.

A palladium sulfide nucleus solution was applied to the aluminum support and 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 0.3 μm to the solution by a control double jet method in an amount of 0.006 mol / mol of silver.
20 mmol% of silver bromide doped with millimoles and 0.1 mol of silver iodide.
A 4 mol% silver chloroiodobromide emulsion was prepared. Thereafter, 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 the sensitizing dye of Chemical Formula 2 per 1 g of silver.

[0037]

Embedded image

A surfactant was added to the silver halide emulsion thus prepared to prepare a coating solution. The emulsion layer coating solution was applied onto 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 3 g / m ² to obtain a lithographic printing material sample.

The lithographic printing material was converted to a 633 nm red LD.
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 21 ° C. for 15 seconds), a washing step (washing off the emulsion layer with a scrub roller while shower-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 compositions of the developing solution, washing solution and finishing solution used are as follows. <Developer> Sodium hydroxide 20 g Hydroquinone 20 g 1-Phenyl-3 pyrazolidinone 2 g Anhydrous sodium sulfite 80 g 2-Mercapto-5-n-heptyl-oxacyazole 0.5 g Monomethylethanolamine 6 g Sodium thiosulfate (pentahydrate) 8 g Ethylenediamine Sodium tetraacetate 5 g Make up to 1000 ml with deionized water. pH (25 ° C.) = 13.4

<Washing solution> 2-mercapto-5-n-heptyl-oxadiazole 0.5 g triethanolamine 13 g sodium bisulfite 10 g potassium phosphate 1 g protease 1 g Water is added to adjust the total amount to 1000 cc. pH is 6.
Adjusted to zero. Bioprolase AL-15 (bacterial proteinase, Nagase Sangyo Co., Ltd.)
Was used.

<Finishing Solution A> Phosphoric Acid 0.5 g Monoethanolamine 5.0 g 2-Mercapto-5-n-heptyloxasiasol 0.5 g Make up to 1000 ml with deionized water. The pH was adjusted to 7.2.

<Finishing liquid B> To finishing liquid A, 20 g of gum arabic was added.

<Finishing Solution C> To finishing solution A, 20 g of polystyrene sulfonic acid was added.

<Finishing Liquid D> To finishing liquid A, 50 g of acrodextrin (degree of polymerization: about 24) was added.

<Finishing liquid E> 50 g of starch was added to finishing liquid A
added.

<Finishing liquid F> To finishing liquid A, 50 g of reduced starch syrup amamil (primary component: 46% monosaccharide, 36% disaccharide, 10% trisaccharide) manufactured by Hayashibara Shoji Co., Ltd. was added.

<Finishing liquid G> The finishing liquid A was prepared by reducing syrup HS-40 (manufactured by Hayashibara Shoji Co., Ltd.).
(3%, trisaccharide 23%) was added.

<Finishing liquid H> The finishing liquid A was made of reduced maltose syrup candy Mavit C (manufactured by Hayashibara Shoji Co., Ltd.)
50 g of saccharides (77%, trisaccharides 3%) were added.

<Finishing Liquid I> To finishing liquid A, 50 g of Maltodextrin manufactured by Hayashibara Shoji Co., Ltd., Sandeck # 180 (main component is 55% of disaccharide to octasaccharide) was added.

The lithographic printing plate prepared by the method described above was used for a printing press Heidelberg MO (trademark of an offset printing press manufactured by Heidelberg) and an ink (Dainippon Ink Co., Ltd.)
Printing was carried out using New Champion Ink H) and a commercially available humidifying solution for PS plates, and the ink acceptability (inking) at the start of printing 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.

Further, the above lithographic printing plate was evaluated for ink detachability. 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. . The results are summarized in Table 1.

[0053]

[Table 1]

As is evident from the results in Table 1, the use of a saccharide having a low degree of polymerization in the finishing liquid can improve the ink releasability without lowering the ink acceptability.

Example 2 Glycerin and glycerol (6
) Or polyethylene glycol (having 10 ethyleneoxy units) were added, and finishing liquids J, K, and L were prepared by adding 40 g of each, and tested in the same manner as in Example 1. As a result, all of the finishing liquids J, K, and L had ink releasability of about 5 sheets. The ink acceptability was 6 to 10 sheets.

[0056]

According to the present invention, a finishing solution containing a saccharide having a low degree of polymerization is applied during plate making of a lithographic printing plate utilizing a silver complex salt diffusion transfer method using an aluminum plate as a support. Excellent ink detachability was obtained without impairing ink acceptability.

Claims (3)

[Claims] 1. A lithographic printing plate finishing solution utilizing silver complex salt diffusion transfer using an aluminum plate as a support, characterized by containing a saccharide having a polymerization degree of 20 or less and a component of 50% by weight or more. Finishing liquid. 2. The finishing solution according to claim 1, further comprising at least one of glycerol, polyglycerol and polyethylene glycol having 2 to 20 ethyleneoxy units. 3. A plate making method comprising exposing a lithographic printing material utilizing a silver complex salt diffusion transfer method having a physical development nucleus between an aluminum support and a silver halide emulsion layer, followed by at least development, washing and finishing. 3. A method of making a lithographic printing plate according to claim 1, wherein the finishing liquid used in the finishing treatment is the finishing liquid according to claim 1 or 2.