JPH07110579A - Developer for lithographic printing plate - Google Patents

Abstract

PURPOSE:To provide a developer very effective in rapid development in a method for making a lithographic printing plate utilizing a silver complex salt diffusion transfer process, not reducing printing resistance or causing defects such as ink stain unlike a developer in the conventional system and adaptable to a rapid processing method by which many lithographic printing plates can rapidly be made with a small amt. of a developer. CONSTITUTION:This developer contains 0.5-50g/l at least one of polyoxyethylene compds. represented by formulae I-III (where 4<=n<=500 and R is H or 2-20C alkyl).

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 developing solution utilizing a silver complex salt diffusion transfer method, and in particular, a lithographic printing plate is coated with a developing solution in an amount necessary for development. It is suitable for the method (hereinafter referred to as rapid processing).

[0002]

2. Description of the Related Art A lithographic printing plate supplies both water and ink to a plate surface to selectively receive a coloring ink in an image area and water in a non-image area, for example, an ink on the image. Printing is performed by transferring to a printing medium such as paper. Therefore, in order to obtain a good printed matter, the difference in the lipophilicity and hydrophilicity of the surface between the image area and the background non-image area is sufficiently large, and when water and ink are applied, the image area contains a sufficient amount of ink. It is necessary that the non-image area accepts no ink.

A lithographic printing plate using a silver complex salt diffusion transfer method (DTR method), particularly a lithographic printing plate having a physical development nucleus layer on a silver halide emulsion layer is described in, for example, US Pat.
No. 114, No. 4,134,769, No. 4,16
0,670, 4,336,321, 4,5
01, 811, No. 4,510, 228, No. 4,
No. 621,041 and the like.

The exposed silver halide crystals undergo chemical development in the emulsion layer by development processing to become blackened silver, forming hydrophilic non-image areas. On the other hand, the unexposed silver halide crystals are solubilized by the silver complex salt forming agent in the developer, diffused to the physical development nucleus layer on the surface, and the reducing action of the developing agent on the physical development nuclei causes the ink-accepting image silver. Is deposited as.

In the plate-making processing method that has been realized for such a lithographic printing plate, an automatic plate-making camera having a developing tank is used. That is, after exposure by the plate-making camera, the printing plate passes through a developer tank, and the developer remaining on the plate surface after passing is removed by a mechanical method, for example, by passing between squeezing rollers having a contact pressure. Then, if necessary, the solution is passed through a neutralizing solution tank to adjust the pH of the plate surface, and the neutralizing solution remaining on the plate surface like the developer is removed by a mechanical method.

In the plate-making processing method as described above, a developer who has a large amount of plate-making processing discharges a large amount of the developer liquid which has become a waste liquid. Economically, it was a heavy burden on employers.

Needless to say, it takes time to pass through the developing solution tank and, if necessary, the neutralizing solution tank, and fatigue of the developing solution due to the processing of a large number of sheets, for example, decrease in pH, generation of sludge, etc. Had.

JP-A-48-76603 and JP-A-57-11
No. 5549 describes a rapid processing method in which an amount of developing solution necessary for developing a lithographic printing plate is applied and supplied to the plate surface to carry out a plate-making process. In rapid processing, it is possible to develop a lithographic printing plate by constantly supplying a fresh developer in the minimum necessary amount.
The development time can be shortened and the fatigue of the developing solution becomes irrelevant.

However, when the conventional developing tank type developing solution is applied to the rapid processing method, various problems occur.
First, the development temperature is suitable. Conventionally, the developing temperature was maintained by adjusting the temperature of the developing tank, but it was found that the developing temperature depends on the lithographic printing plate temperature in the rapid processing system. However, it is difficult to control the temperature of the lithographic printing plate with high precision in terms of the apparatus, and it is necessary to have a wide temperature range suitable for the developing solution. Secondly, the printing durability is reduced. It has been found that the rapid processing method requires a small amount of liquid and completes the development in a few seconds, so that the strength of the image portion that can withstand printing cannot be obtained unless the developing efficiency is increased. Third is ink stains.
It was found that when a conventional developing bath type developing solution was applied to the rapid processing system, the printing plate image became soft and the non-image area was easily soiled.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to provide DT
It is an object of the present invention to provide a developing solution for a lithographic printing plate utilizing the R method, which is suitable for a rapid processing system, has a wide developing temperature suitability range, does not deteriorate in printing durability, and does not cause ink stain resistance.

[0011]

The above objects of the present invention are as follows.
A developer used in a method of developing by supplying a developer only to the surface coated with a silver halide emulsion layer, and containing at least one polyoxyethylene compound represented by the following general formula. Was achieved by using a developer characterized by:

[0012]

[Chemical 4]

[0013]

[Chemical 5]

[0014]

[Chemical 6]

N = 4 to 500, R is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.

A more detailed description will be given below. The rapid processing method described in the present invention is a method in which the developing solution is applied and supplied only to the surface on which the silver halide emulsion layer is applied.
No. 8-76603. For example, liquid coating method, dropping method roller coating method, dropping knife coating method,
There are spray coating methods, brush coating methods, etc., but not limited to these. For simplicity, a so-called doctor bar in which a bar is wound around a rod made of an appropriate material can be used. Specifically, the development is performed on the surface of the printing plate which is kept horizontal and coated with the silver halide emulsion layer. A method of dropping the solution and spreading the developing solution with a doctor bar can also be adopted.

In the sense of rapid processing, the coating amount of the developing solution on the planographic printing plate is 10-1 per square meter of the printing plate.
It is in the range of 50 ml, preferably in the range of 20-80 ml, and the developing time (the time from application of the developing solution until the developing solution stops the developing effect) is 15 seconds or less, preferably in the range of 2-10 seconds. The development temperature depends on the temperature control accuracy, but it is 20-4
It has a width of 5 ° C.

In the plate making method using the developing solution of the present invention, for example, a planographic printing plate is first coated with the developing solution, and then the developing solution on the plate surface is removed by a squeezing roller or the like. Next, if necessary, p
To reduce H, a neutralizing solution or washing with water is performed, and further, in an automatic plate making machine or the like, the plate making is completed through a drying step. Of course, a step of heating the lithographic printing plate or the developing solution can be included if necessary during the plate making step.

The polyoxyethylene compound represented by the above general formula used in the present invention has an oxymethylene chain length of n.
= 4 to 500, preferably 20 to 200,
R is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. These compounds can be easily obtained as commercial products such as chemicals and chemical products. Specific examples are shown below, but the present invention is not limited thereto.

[0020]

[Chemical 7]

[0021]

[Chemical 8]

[0022]

[Chemical 9]

[0023]

[Chemical 10]

[0024]

[Chemical 11]

[0025]

[Chemical 12]

[0026]

[Chemical 13]

[0027]

[Chemical 14]

[0028]

[Chemical 15]

[0029]

[Chemical 16]

[0030]

[Chemical 17]

[0031]

[Chemical 18]

[0032]

[Chemical 19]

[0033]

[Chemical 20]

[0034]

[Chemical 21]

[0035]

[Chemical formula 22]

[0036]

[Chemical formula 23]

[0037]

[Chemical formula 24]

[0038]

[Chemical 25]

The amount of the above compound used in the present invention contained in the developer is 0.5 g / l-50 g / l, preferably 1 g / l-20 g
The range is / l.

In the developing solution used in the present invention, alkaline substances such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium triphosphate, etc., sulfites as preservatives, silver complex forming agents, eg, Thiosulfates, alkanolamines, thiocyanates, cyclic imides, thiosalicylic acid, etc., viscous agents such as hydroxymethyl cellulose, carboxymethyl cellulose, antifoggants,
For example, potassium bromide, 1-phenyl-5-mercaptotetrazole, the compounds described in JP-A-47-26201 and the like, and developers such as hydroquinone and 1-phenyl-3-pyrazolidone can be contained.

In carrying out the DTR method, for example, British Patent Nos. 1,000,115, 1,012,476 and 1,017,
No. 273, No. 1,042,477, etc., a developer is incorporated into a silver halide emulsion layer and / or an image receiving layer or another water permeable layer adjacent thereto. There is. Therefore, in such a material,
The processing solution used in the development stage may be a so-called "alkaline activating solution" containing no developer.

The silver halide emulsion of the lithographic printing plate used in the practice of the present invention can use silver chloride, silver bromide, silver chlorobromide, silver chloroiodide, silver chlorobromoiodide, etc., and preferably silver chloride. Is 5
It is 0 mol% or more of silver halide. These silver halides are spectral sensitizers (light sources, spectral sensitizing dyes depending on the application,
For example, camera type, laser light type, color separation panchromatic type, etc. ), Gelatin hardening agents, coating aids, antifoggants, plasticizers, developers, matting agents and the like.

Binders for silver halide emulsions are the natural and / or synthetic binders commonly used for this purpose.
For example, gelatin, colloidal albumin, cellulose derivative and the like can be used.

An undercoat layer for improving adhesion and / or an undercoat layer for the purpose of preventing halation may be included on the lower side (support surface) of the silver halide emulsion layer.
A matting agent can also be included.

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

The physical development nuclei used in the physical development nuclei layer are
Examples of this type of chemical are well known and include antimony, bismuth, cadmium, cobalt, palladium, nickel,
Metals such as silver, lead and zinc and their sulfides can be used. The physical development nucleus layer may also contain a developer and may contain a water-soluble binder.

The lithographic printing plate produced according to the present invention is, for example, Japanese Patent Publication No. 48-29723, US Pat. No. 3,721,539.
Ink receptivity can be converted or enhanced by a compound as described in the specification.

The printing method or the desensitizing liquid, dampening liquid or the like to be used can be based on a commonly known method.

[0049]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. Example 1 A silver master (trade name) manufactured by Mitsubishi Paper Mills, Ltd. was used as a lithographic printing plate utilizing the DTR method. The lithographic printing plate precursor was imagewise exposed with a plate-making camera having an image reversing mechanism.

Then, the imagewise exposed lithographic printing plate was placed on a horizontal glass plate kept at a predetermined temperature (20 ° C., 30 ° C., 40 ° C.) in a room kept at about 25 ° C. Using a surface thermometer (IT-330, Horiba Seisakusho Co., Ltd.), check that the surface temperature of the lithographic printing plate has reached the specified temperature.
The developing solutions shown below were dropped and spread with a doctor bar. The doctor bar is a stainless steel rod having a diameter of 5 mm and a wire having a diameter of 0.4 mm wound around it.

After being spread, it was left for about 5 seconds, immediately washed thoroughly with water and dried.

[0052]

[Table 1]

As the polyoxyethylene compound,
0 compounds were used.

Next, these lithographic printing plates were dried, set on a Heidenberg TOK offset printing machine, the following desensitizing liquid was applied all over the plate surface, and printing was carried out using a dampening liquid having the following composition. It was As the printing ink, F-Gloss Indigo Blue (manufactured by Dai Nippon Paper Industries Co., Ltd.) was used for the evaluation of stain resistance, which is particularly susceptible to ink stains.

[0055]

[Table 2]

The printed matter obtained was evaluated according to the following evaluation criteria. Printing durability: ◯: 20,000 sheets or more △: 10,000 sheets or more ×; 5,000 sheets or more Ink stain resistance: ◯: No stain Δ: All or partial light stain ×: Thick stain on the entire surface

The evaluation results are shown in Table 3.

[0058]

[Table 3]

Example 2 In Example 1, polyethylene glycol (n = 91)
Instead of polyethylene glycol (n = 2, 5, 10
(0, 200, 600) was carried out in the same manner as in Example 1 except that the following developing solutions were prepared and used individually. Developer solution Water 700 g Potassium hydroxide 17 g Sodium hydroxide 7 g Anhydrous sodium sulfite 35 g 2- (2-aminoethylamino) ethanol 10 g Polyoxyethylene compound 5 g Water to make a total volume of 1 l.

The results are shown in Table 4.

[0061]

[Table 4]

Example 3 The same result as in Example 1 was carried out in the same manner as in Example 1 except that each of Chemical formula 20, Chemical formula 21 and Chemical formula 23 was used instead of Chemical formula 10. Got

From the results, it is clear that the planographic printing plate and the ink stain resistance of the lithographic printing plate rapidly processed using the developing solution containing the polyoxyethylene compound as shown in the present invention are remarkably improved. Also, the temperature range suitable for development of the developer is
It is extremely effective for rapid processing that spreads to lower temperatures and the development temperature depends on the temperature of the printing plate.

[0064]

According to the developer of the present invention, it is extremely effective for the rapid processing developing method, and there are drawbacks such as reduction of printing durability and occurrence of ink stain, which are observed when the developer of the conventional system is applied. It is possible to make a large number of planographic printing plates quickly and with a small amount of developing solution.

Claims (1)

[Claims] 1. A developer for use in a method of making a lithographic printing plate using a silver complex salt diffusion transfer method by supplying a developer only to the surface coated with a silver halide emulsion layer and developing. A developer containing at least one polyoxyethylene compound represented by the following general formula. [Chemical 1] [Chemical 2] [Chemical 3] n = 4 to 500, R is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.