JPH0588376A - Developer for lithographic printing plate - Google Patents

Abstract

PURPOSE:To obtain a processing soln. contg. a diffusion transfer accelerator and excellent in plate wear in a developer for the direct lithographic printing plate utilizing a silver complex salt diffusion transfer process. CONSTITUTION:This novel diffusion transfer accelerator is shown by the formula. In the formula, R is alkyls (e.g. ethylene, propylene and tetramethylene), Z is an atomic group (e.g. thiazoline ring, pentiazoline ring, etc.), X is sulfur atom, and (n) is 1 to 4. The direct lithographic printing plate prepared by this developer is improved in the omission of the transfer silver image, the printing resistance is remarkably ameliorated, and the ink receivability is not deteriorated.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a developer used for a lithographic printing plate by a silver complex salt diffusion transfer method.

[0002]

2. Description of the Related Art An offset printing plate using a silver image obtained by a silver complex salt diffusion transfer method (DTR) has already been described in JP-B-46-43132 and JP-A-48-30562, and further positive type printing. For the original plate, JP-A-49-55402, and for the negative type printing original plate, JP-A-52-106902 and 52-112.
No. 402 and the like are described in detail.

These direct printing plates are composed of a subbing layer for preventing halation, a silver halide emulsion layer, and a physical development nucleus layer on a support. When this printing plate is imagewise exposed and then developed, the silver halide on which a latent image is formed becomes blackened silver in the emulsion layer. The silver halide on which a latent image is not formed is dissolved by the action of a silver halide complexing agent such as sulfite in the developing solution and diffuses to the surface of the light-sensitive material. The diffused silver complex salt forms a silver image on the physical development nuclei by the reducing action of the developing agent. In order to enhance the ink receptivity of the silver image thus obtained, it is subjected to an oil-sensitizing treatment, set on an offset printing machine, and the ink image is transferred to a printed matter.

The direct photographic printing material has advantages such as excellent operability and cost, but on the other hand, excessive silver ions tend to remain because of the nature of forming a printing silver image by photographic development processing. It has been one of the causes of deterioration of storage stability or printing durability. Various methods are utilized to remedy these drawbacks. One is the use of oxidizing agents. JP-A-55-98753 describes the combined use of a sulfur-containing organic compound and an oxidizing agent, and also JP-A-5-98753.
1-58952 and 61-223740 describe a method of improving printing durability using iodine ions and an oxidizing agent. Further, the removal of excessive silver ions by using the chelate resin was also effective in increasing the printing durability. However, these methods often tend to lower the ink acceptability of silver images, and there has been no satisfactory method for increasing the printing durability without lowering the ink acceptability.

[0005]

DISCLOSURE OF THE INVENTION An object of the present invention is to obtain a silver image having good printing durability and high ink acceptability in the development process of a direct lithographic printing plate utilizing a silver complex salt diffusion transfer method. To provide the liquid.

[0006]

The object of the present invention has been achieved by adding a diffusion transfer accelerator represented by the chemical formula 2 during the development processing.

[0007]

[Chemical 2]

In the formula, R represents an alkylene group (for example, ethylene, propylene, tetramethylene), and Z is 5 to 5.
Represents an atomic group (for example, thiazoline ring, penthiazoline ring) necessary for forming a 6-membered heterocycle, n is 1 to 4
Represents.

Representative examples of the compound of Chemical formula 2 used in the present invention are shown below.

[0010]

[Chemical 3]

[0011]

[Chemical 4]

[0012]

[Chemical 5]

[0013]

[Chemical 6]

[0014]

[Chemical 7]

[0015]

[Chemical 8]

[0016]

[Chemical 9]

These compounds are commercially available, for example, from the Journal of Chemical Society (JCS) 72 ,
1879 (1950), Journal of Organic Chemistry (JOC) 24 , 470 (19).
53), Britain Chemical Society (Bul
l. Chem. Soc. ) 40 , 2854 (196)
7), Pharmaceutical Journal 85 , 1537 (1968), Japanese Patent Publication Sho 3
9-26203, 60-11341, etc., for easy synthesis. The details of the synthesis method will be described below using synthesis examples.

Synthesis Example 1 (Synthesis of Exemplified Compound 3) To 2.66 g of 2-methylthiothiazoline, 3.64 g of 2-chloro-2'-hydroxydiethyl sulfide is added. Heat at 150 ° C-160 ° C for 3 hours. After cooling, 10 ml of pyridine was added to the reaction mixture, the mixture was heated to 100 ° C. for 2 hours, water was added to the reaction mixture, and the mixture was extracted with chloroform. The chloroform layer was washed with water, dried over anhydrous sodium sulfate, chloroform was distilled off, and the residue was separated by column chromatography (chloroform / methanol = 10/1) to obtain 2.51 g of a pale yellow oil. CMR (CDCL ₃ ) δ197.0, 60.9,
57.4, 48.8, 35.2, 28.3, 27.5P
MR (CDCL ₃ ) δ 4.18, 3.96, 3.79,
3.33, 2.88, 2.85

The amount of the compound of the present invention added to the developer is
The range of 0.01 to 10.0% by weight is preferable, and especially 0.01
The range of ˜4.0 wt% is preferred.

The developing solution of the present invention contains an alkaline substance such as sodium hydroxide, potassium hydroxide, lithium hydroxide and sodium triphosphate and a sulfite salt (potassium sulfite, sodium sulfite, etc.) as a preservative. It is essential, but other compounds such as sulfates (sodium sulfate, ammonium sulfate, etc.), wetting agents such as polyol compounds having two or more hydroxy groups (polyethylene glycol, propylene glycol, pentaerytriol, glycerol, hexylene glycol). Etc.), silver halide solvent (thiosulfate, thiocyanate, cyclic imide, thiosalicylic acid, amine, etc.), thickener (gum arabic, hydroxyethyl cellulose (HE
C), carboxemethyl cellulose (CMC), sodium alginate, vinylpyrrolidone (PVP), vinyl imidazole, methyl vinyl ether-maleic anhydride copolymer, carboxymethyl starch, ammonium alginate, alginate oxydide cellulose, methyl cellulose, etc.), fogging prevention Agent (potassium bromide, 1-phenyl-5-mercaptodetrazole, JP-A-47-2
6201), developing agents (hydroquinone, 1-phenyl-3-pyrazolidone, methol, phenidone, catechol, pyrogallol, glycine, chlorohydroquinone, etc.), development modifiers (polyoxyalkylene compounds, onium compounds), etc. It may be included. Furthermore, one or more surfactants [propylene glycol alginate, aminopolycarboxylic acid salts (sodium ethylenediaminetetraacetate, etc.)] may be contained. In addition to this, a water-miscible organic solvent for the solvent of the compound of the present invention (methanol, ethanol, propanol, isopropyl alcohol, n-butyl alcohol, dimethylformaldehyde, dioxane, etc.) can be included.

In carrying out the complex salt diffusion transfer method, for example, British Patent Nos. 1,000,115 and 1,012,47.
No. 6, No. 1,017,273, No. 1,042,477
It is practiced to incorporate a developing agent into the silver halide emulsion layer and / or the image-receiving layer or another water-permeable layer adjacent thereto as described in the specification of U.S. Pat. Therefore, in such a light-sensitive material, the processing solution used for development may be a so-called "alkaline activating solution" containing no developing agent.

The silver halide emulsion of the lithographic printing plate used in the practice of the present invention may be silver chloride, silver bromide, silver chlorobromide, silver chloroiodide or silver chlorobromoiodide, preferably silver chloride. Fifty
It is a silver halide of mol% or more. These silver halide emulsions include spectral sensitizers (light sources, spectral sensitizing dyes depending on the application, such as camera type, laser light type, panchromatic type for color separation), gelatin hardening agents, coating aids, antifoggants. , A plasticizer, a developing agent, a matting agent and the like.

The binder used in the silver halide emulsion of the lithographic printing plate of the present invention is usually gelatin. Gelatin is a part of starch, albumin, sodium alginate, hydroxyethyl cellulose (HEC),
Hydrophilic polymer bonds such as gum arabic, polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), carboxymethyl cellulose (CMC), polyacrylamide, styrene-maleic anhydride copolymer, polyvinyl methyl ether-maleic anhydride copolymer, etc. It is also possible to substitute with one or more agents. Further, an aqueous dispersion of vinyl copolymer (latex) can also be used.

On the lower side (support surface) of the silver halide emulsion layer, an adhesion improving subbing layer and / or a subbing layer for the purpose of preventing halation may be contained, and a developing agent and a matting agent are contained in this layer. Can be included.

The support on which the silver halide emulsion is coated is
Paper, various films, plastics, paper coated with resin-like substances, metal plates, etc. can be used.

Physical development nuclei used in the physical development nuclei layer are known to be chemicals of this kind, and include antimony, cadmium,
Metals such as cobalt, palladium, nickel, silver, lead and zinc, and their sulfides can be used. The physical development nucleus layer may also contain a developing agent, or may contain a hydrophilic binder.

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1 A matting layer containing silica particles having an average particle size of 5 μ was provided on one side of a polyester film support which had been subjected to subbing treatment, and carbon black in an amount that would give a light reflectance of 3% was provided on the opposite side. A halation-preventing subbing layer (adjusted to pH 4.0) containing 20% by weight of silica powder having an average particle size of 7 μm with respect to photographic gelatin, and a silica powder having an average particle size of 7 μm after being chemically sensitized. Spectral-sensitized high-sensitivity silver chloride emulsion layer containing 5% by weight of photographic gelatin (p
(Adjusted to H4.0). The gelatin of the undercoat layer is 3.
5 g / m ² , the gelatin in the emulsion layer was 0.8 g / m ² , and the silver halide in terms of silver nitrate was 1.0 g / m ² . The subbing layer and the emulsion layer contain formalin as a hardening agent in an amount of 5.0 mg / g based on gelatin. After drying and heating at 40 ° C. for 14 days, the emulsion layer was
Plate No. 31 of Example 2 of JP-A-54-103104
The core liquid described is applied and dried to produce a lithographic printing plate. The silver halide emulsion was prepared by adding 4 × 10 ⁻⁶ mol of rhodium chloride per mol of silver halide during physical ripening, and had an average grain size of 0.40 μm. The original plate of the lithographic printing plate thus obtained was image-exposed with a plate-making camera having an image reversal mechanism, and developed with the following developer A (use solution) at 30 ° C. for 30 seconds, followed by the following neutralizing solution. Processed in.

Developer A Sodium hydroxide 24 g Potassium hydroxide 8 g Anhydrous sodium sulfite 50 g 2-Methyl-2-amino-1-propanol 30 g Uracil 0.2 g Water is added to make 1 liter.

Neutralizing solution Ethylene glycol 5 g Colloidal silica (20% aqueous solution) 1 g Citric acid 10 g Sodium citrate 35 g Water is added to make 1 liter.

On the other hand, for the purpose of comparison with the developer A, a developer B (B1 to B8) was prepared by adding the compound of the chemical formula 3 of the present invention into the developer, and the developer A was completely used. Plate-making processing was carried out similarly. Then, the printing plate was set in an offset printing machine, the plate surface was sufficiently wetted with an etchant having the following composition, and printing was performed using a dampening solution having the following composition.

Etching solution Water 600 ml Isopropanol 400 ml Ethylene glycol 50 g 3-Mercapto-4-acetamido-5-n-butyl-1,2,4-triazol 1 g

Humidifying liquid Water 8 l Succinic acid 6 g Sodium sulfate 25 g Ethylene glycol 100 g Colloidal silica (20% aqueous solution) 28 g

The printing machine is ABCD350CD
(Trademark of offset printing machine manufactured by AB Dick) was used. The printing durability of printing was judged by the following method. 1,
Printing was continued from 000 sheets to 50,000,000 sheets, and the following five levels were evaluated according to the number of printed sheets when the ink spreads in the silver image area. A 50,000 or more B 50,000 or less C 25,000 or less D 5,000 or less E 2,000 or less

[0035]

[Table 1]

The printing plate obtained with the developer A has a thickness of 5,000.
In contrast to the partial missing of the transferred silver image by the number of sheets,
The printing plate obtained with the developer B (B1 to B8) of the present invention is
Even with 10,000 sheets, the transfer silver image was not lost.

Example 2 A plate-making process was carried out in the same manner as in the developer A except that 0.5 g / l of each of Chemical formulas 4 to 9 was added instead of Chemical formula 3 used in the developer B of Example 1. Processed. The printing results are shown in Table 2. The printing durability was better than that of Developer A in all cases.

[0038]

[Table 2]

[0039]

EFFECTS OF THE INVENTION The planographic printing plate prepared by the developing solution of the present invention is improved in the lack of transferred silver image, the printing durability is remarkably improved, and the ink receiving ability is not deteriorated.

Claims (1)

[Claims] 1. A developer for a lithographic printing plate using a silver complex salt diffusion transfer method, which contains at least one compound represented by the following formula: [Chemical 1] In the formula, R represents an alkylene group, Z is an atomic group necessary for forming a 5- or 6-membered heterocycle, and n represents 1 to 4.