JPH04328559A - Developer for lithographic printing plate - Google Patents

Abstract

PURPOSE:To obtain a processing solution for forming the recorded picture having favorable printing resistibility and excellent in ink receptivity by adding a specified diffusion transfer accelerator to a developing processing solution. CONSTITUTION:At least one kind of compound expressed as formula I is incorporated into o developer for lithographic printing plate utilizing silver complex salt diffusion transfer method. In formula I, X is sulfur atom or oxygen atom, R1 is alkyl group, aryl group, aralkyl group, dialkylamino group, and R2 is hydrogen atom, alkyl group, aryl group, aralkyl group, dialkylamino group. Adding quantity of this solution to the developer is preper to a range of 0.01-10.0wt.%, especially a range of 0.01-4.0wt.% is favorable. A lithographically printing plate made of this developer is improved the omission of transfer silver image, drastically improved the plate wear and the deterioration of ink receptivity is prevented.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer used for lithographic printing plates produced by silver complex diffusion transfer.

0002

[Prior Art] An offset printing plate using a silver image obtained by the silver complex diffusion transfer method (DTR) has already been disclosed in Patent Publication No. 46-43132 or Patent Publication No. 48-3.
0562, and the positive type printing original plate is described in Published Patent Publication No. 1983-55402.
Regarding negative type printing plates, see the published patent publication 1972-
It is described in detail in No. 106902, Japanese Patent Publication No. 112402/1980, and the like.

[0003] These direct printing plates consist of a support and on the support a subbing layer that also serves as antihalation layer, a silver halide emulsion layer, and a physical development nucleus layer. The silver halide on which a latent image has been formed by development becomes blackened silver in the emulsion layer. On the other hand, silver halide on which no latent image has been formed is dissolved by the action of a silver halide complexing agent contained in the processing solution and diffused onto the surface of the photosensitive material. The silver complex salt that has been dissolved and diffused is deposited as a silver image on the physical development nuclei in the surface layer by the reducing action of the developing agent. In order to enhance the ink receptivity of the silver image obtained in this way, after development, a sensitizing treatment is applied if necessary, and the ink image is transferred to a printed matter by setting the silver image in an offset printing machine. Direct photographic printing materials have advantages such as excellent operability and low cost, but on the other hand, because the silver image for printing is formed through photographic development processing, excessive silver ions tend to remain, which makes storage stability difficult. This caused a decrease in durability or printing durability.

Various methods are available to remedy these shortcomings. One of them is the use of oxidizing agents. JP-A-55-98753 describes the use of a sulfur-containing organic compound in combination with an oxidizing agent, and JP-A-51-5
No. 8952 and No. 61-223740 describe a method of improving printing durability using iodine ions and an oxidizing agent. Additionally, removing excess silver ions by using a chelate resin was also effective in increasing printing durability. However, these methods often tend to reduce the ink-receiving ability of silver images, and there has been no satisfactory method for increasing printing durability without reducing the ink-receiving ability.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to obtain a silver image with good printing durability and high ink receptivity in the development process of a direct lithographic printing plate using the silver complex diffusion transfer method. The purpose is to provide a developer.

[0006]

[Means for Solving the Problems] The object of the present invention was achieved by adding a diffusion transfer accelerator represented by Chemical Formula 2 to the above-mentioned developing solution.

[0007]

[Case 2]

[0008] In the formula, X represents S or O, and R1 is
It represents an alkyl group, an aryl group, an aralkyl group, a dialkylamino group, and R2 is a hydrogen atom or an alkyl group,
Indicates an aryl group, an aralkyl group, and a dialkylamino group.

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

0010

[Chemical formula 3]

[0011]

[C4]

0012

[C5]

[0013]

[C6]

[0014]

[C7]

[0015]

[Chemical formula 8]

[0016]

[Chemical formula 9]

[0017]

[Chemical formula 10]

[0018]

[Chemical formula 11]

[0019]

[Chemical formula 12]

[0020]

[Chemical formula 13]

[0021]

[Chemical formula 14]

[0022]

[Chemical formula 15]

[0023]

[Chemical formula 16]

These compounds are described, for example, in the Journal of the Chemical Society [J. Chem. Soc, Pe
rkin. Trans. I 627 (1974)],
Journal of Heterocyclic Chemistry
[J. Heterocycle. Chem. 5277
(1968)], Tetrahedron Letters [Tera
hedron Lett. 5881 (1968)
], same [Terahedron Lett. 1809-1
4 (1967)], US Pat. No. 4,939,075, and the like. The amount of the compound of chemical formula 2 of the present invention added to the developer is preferably in the range of 0.01 to 10.0% by weight, particularly 0.01% by weight.
A range of 4.0% by weight is preferred.

It is known to use water-soluble polymers such as carboxymethyl cellulose (CMC) and hydroxyethyl cellulose (HEC) as thickeners in diffusion transfer developers for lithographic printing plates (for example, special Kaisho 48-76603
No. 56-6237, etc.) may be added to the treatment solution of the present invention, but these polymer compounds
There is no action to improve printing durability.

The developing solution of the present invention contains an alkaline substance,
For example, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium triphosphate, etc. and sulfites (potassium sulfite, sodium sulfite, etc.) as preservatives are essential, but other compounds such as sulfates (sodium sulfate, etc.) are essential. ,
ammonium sulfate, etc.), silver halide solvents such as thiosulfate, thiocyanate, thioether, cyclic imide,
Thickening agents such as thiosalicylic acid and alkanolamines, such as hydroxyethylcellulose (HEC) and carboxymethylcellulose (CMC), antifoggants such as potassium bromide and sodium bromide, developing agents, For example, hydroquinone, 1-phenyl-3-pyrazolidonemeth-
It may contain a developer modifier such as a polyoxyalkylene compound, an onium compound, etc. Furthermore, one or more surfactants such as alginate propylene glycol ester, aminopolycarboxylic acid salts (sodium ethylenediaminetetraacetate, etc.) may be included.In addition, solvents for the compounds of the present invention, such as methane -ol, ethanol, propanol, isopropyl alcohol, n-butyl alcohol, dimethyl formaldehyde,
Water-miscible organic solvents such as dioxane 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 has been practiced to incorporate developing agents into the silver halide emulsion layer and/or into the image-receiving layer or other water-permeable layers adjacent thereto. Therefore, in such a photosensitive material, a so-called "alkaline activating solution" which does not contain a developing agent may be used as a processing solution for development.

As the silver halide emulsion for the lithographic printing plate used in the practice of the present invention, silver chloride, silver bromide, silver chlorobromide, silver chloroiodide, and silver chlorobromoiodide can be used, and silver chloride is preferable. 50
It is silver halide with a mole % or more. These silver halide emulsions contain spectral sensitizers (spectral sensitizing dyes depending on the light source and purpose, such as camera type, laser light type, panchromatic type for color separation, etc.), gelatin hardeners, coating aids, It can contain antifoggants, plasticizers, developing agents, matting agents, and the like.

The binder used in the silver halide emulsion of the lithographic printing plate of the present invention is usually gelatin, and gelatin is partially composed of starch, albumin, sodium alginate, hydroxyethylcellulose (HEC),
Gum arabic, polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), carboxymethylcellulose (CMC), polyacrylamide, styrene-maleic anhydride copolymer, polyvinyl methyl ether-maleic anhydride copolymer It can also be replaced with one or more hydrophilic polymer binders such as. Furthermore, a vinyl copolymer aqueous dispersion (latex) can also be used.

The underside (support side) of the silver halide emulsion layer may contain an undercoat layer for the purpose of improving adhesion and/or preventing halation. agent.

As the support to which the silver halide emulsion is coated, paper, various films, plastics, paper coated with a resin-like substance, metal plate, etc. can be used.

The physical development nuclei used in the physical development nucleus layer are:
Chemicals of this type are well known and can include metals such as antimony, cadmium, cobalt, palladium, nickel, silver, lead, zinc, and their sulfides. This physical development nucleus layer can also contain a developing agent, or a hydrophilic binder.
May include.

The compound of chemical formula 2 of the present invention can be used in a photolithographic process solution such as a stop solution or a fixer solution used subsequent to processing with the developer solution of the present invention, or in a printing process step such as a desensitizing solution or a dampening solution. Although it can be contained alone or in combination in various processing solutions used for processing, it is particularly effective to include it in a developing processing solution.

[0034]

[Examples] The present invention will be specifically explained below using examples, but it is of course not limited thereto.

Example 1 A matting layer containing silica particles having an average particle size of 5 μm was provided on one side of a subbed-treated polyester film support, and a matting layer containing silica particles with an average particle size of 5 μm was provided on the other side, and an amount of paint was applied on the opposite side to give a light reflectance of 3% at 633 nm. - an antihalation subbing layer (adjusted to pH 4.0) containing bomb black and 20% by weight of silica powder with an average particle size of 7 μm based on photographic gelatin and an average particle size after being chemically sensitized; A spectrally sensitized high-sensitivity silver chloride emulsion (adjusted to pH 4.0) containing silica powder with a diameter of 7 μm at a ratio of 5% by weight based on photographic gelatin was provided. Gelatin for the undercoat layer was coated at a rate of 3.5 g/m2, gelatin for the emulsion layer at a rate of 0.8 g/m2, and silver halide converted to silver nitrate at a rate of 1.0 g/m2. The undercoat layer and emulsion layer contained 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, JP-A-54-
103104 Publication Example 2 Plate No. A lithographic printing plate is produced by applying the nuclear solution described in 31 and drying it. The silver halide emulsion had 4 x 10-6 mol of rhodium chloride added per mol of silver halide during physical ripening, and had an average grain size of 0.40 microns. The original plate of the planographic printing plate obtained in this way was exposed to light using a plate-making camera having an image reversal mechanism, and the following developing solution A (working solution) was used for 30 minutes.
It was developed at ℃ for 30 seconds, and then treated with the following neutralizing solution.

Developer solution A Sodium hydroxide

24g potassium hydroxide

8g anhydrous sodium sulfite

50g 2-methyl-2-amino-1-
Propanol 30g
Uracil

Add 0.2 g of water to make 1 liter.

Neutralizing liquid ethylene glycol

5g colloidal silica (20% aqueous solution)
1g
citric acid

10g sodium citrate

Add 35 g of water to make 1 liter.

On the other hand, for comparison purposes, developer solutions B to I were prepared by adding exemplified compound 3 of the present invention in the amount shown in Table 1 to developer solution A described above. Development was carried out in exactly the same manner as developer A described above. The printing plate was then set in an offset printing machine, the plate surface was sufficiently moistened with an etchant having the composition shown below, and printing was carried out using a dampening liquid having the composition shown below.

Etch liquid water

600ml isopropanol

400ml ethylene glycol

50g 3-mercapto-
4-acetamido-5-n-
Butyl-1,2,4-triazole
1g

Moisturizing liquid water

8l succinic acid

6g sodium sulfate
25g
ethylene glycol
100g
Colloidal silica (20% aqueous solution)
28g

[0041]
The printing machine was an A.B.Dick 350CD (A.B.D.
An offset printing machine (trademark) manufactured by IKE Co., Ltd. was used. In the printing plate obtained with developer A, partial loss of the transferred silver image occurred by 5,000 sheets, whereas in the printing plates obtained with developers B to I of the present invention, partial loss of the transferred silver image occurred by 5,000 sheets. No loss of the transferred silver image occurred even on the sheet. The compounds used in Example 1 and the amounts added are shown in Table 1, and the printing results determined according to the following criteria are shown in Table 1. After continuous printing of 1,000 to 50,000 sheets, the following four levels were evaluated based on the number of prints when ink splattered in the silver image area. A50,0
00 or moreB 25,000C 10,00
0D 5,000

[0042]

[Table 1]

Example 2 Compounds 4 to 16 were each used in place of compound 3 used in developer solutions B to I of Example 1.
．． Plate making was carried out in exactly the same manner as in Comparative Developer A above, except that 5 g/l was added. The printing results are shown in the table. All had better printing durability than developer A. The results of the compounds used in Example 2 are shown in Tables 2 and 3, which were evaluated using the same method as in Example 1.

[0044]

[Table 2]

[0045]

[Table 3]

As is clear from Tables 2 and 3, the addition of the compound of formula 2 produced image silver with excellent printing durability.

[0047]

Effects of the Invention: The lithographic printing plate made with the developer of the present invention has improved loss of transferred silver images, has dramatically improved printing durability, and has no deterioration in ink receptivity.

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. [Formula A] (In formula A, X represents S or O, R1 represents an alkyl group, aryl group, aralkyl group, or dialkylamino group, and R2 represents a hydrogen atom, an alkyl group, an aryl group, or a dialkylamino group. )