JP3311479B2 - Lithographic printing plate developer - Google Patents

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 developer utilizing a silver complex salt diffusion transfer method, and more particularly, to a lithographic printing plate which is supplied with an amount of developing solution necessary for developing the lithographic printing plate. It is suitable for a method of coating and developing (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, and selectively receives a colorable ink in an image portion and water in a non-image portion. Printing is performed by transferring the image onto a printing medium such as paper. Therefore, in order to obtain good printed matter, the difference between 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 requires a sufficient amount of ink. It is necessary that the receiving and non-image parts do not receive any 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 disclosed in, for example, US Pat. No. 3,728,
No. 114, No. 4,134,769, No. 4,16
Nos. 0,670, 4,336,321 and 4,5
No. 01,811, No. 4,510,228, No. 4,
621,041.

[0004] The exposed silver halide crystal undergoes chemical development in the emulsion layer by a development process to become blackened silver, thereby forming a hydrophilic non-image portion. On the other hand, the unexposed silver halide crystals are solubilized by the silver complex salt forming agent in the developing solution, diffused to the physical development nucleus layer on the surface, and reduced on the physical development nuclei by the reducing action of the developing agent to form an image-receptive image silver. Precipitates as

[0005] In the plate making processing method that has been realized for such a lithographic printing plate, a developing tank and a stabilizing tank (neutralizing tank) are used.
An automatic plate-making camera with a built-in is used.

[0006] In the above plate making method, a large amount of plate developer requires a large amount of waste developer to be discharged, and the storage and processing of these waste liquids requires environmental protection. It was economically burdensome for employers.

[0007] Needless to say, it takes a long time to pass through the developing solution tank and, if necessary, the neutralizing solution tank, and also disadvantages such as fatigue of the developing solution due to processing of a large number of sheets, such as a decrease in pH and generation of sludge. Had.

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

However, when the developing solution used in the conventional developing tank system is applied to the rapid processing system, various problems occur. First, it is appropriate for the development temperature. Conventionally, the developing temperature was maintained by adjusting the temperature of the developing tank. However, it was found that the developing temperature depends on the lithographic printing plate temperature in the rapid processing method. However, it is difficult to precisely control the temperature of the lithographic printing plate in terms of equipment, and it is necessary to provide a suitable temperature range for the developer. Second, printing durability is reduced. In the rapid processing method, since the development is completed in a few liquids and within several seconds, it was found that unless the development efficiency was increased, the strength of the image portion that could withstand printing could not be obtained. Third, ink stains. When the developer used in the conventional developing tank method is applied to the rapid processing method, the printing plate image softens,
It was found that the non-image portion was easily stained.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a DT
An object of the present invention is to provide a developing solution for a lithographic printing plate utilizing the R method, which is suitable for a rapid processing method, has a wide range of developing temperature suitability, does not decrease printing durability, and does not generate ink stain.

[0011]

SUMMARY OF THE INVENTION The above objects of the present invention are as follows.
A developer used in a method of supplying a developer necessary for developing a lithographic printing plate using the DTR method and performing coating and developing,
This was basically achieved by using a developer characterized by containing at least one kind of polyoxyethylene compound represented by the following general formula.

[0012]

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[0013]

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[0014]

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

The details will be described below. The rapid processing method described in the present invention is a method in which a necessary developing solution is supplied to a light-sensitive material and coating and development are performed.
No. 3. For example, there are a liquid coating method, a dropping roller coating method, a dropping knife coating method, a spray coating method, a brush coating method, and the like, but are not limited thereto. For simplicity, a so-called doctor bar, in which a line is wound around a rod made of a suitable material, can also be used. Specifically, the developing plate is developed on the surface of the printing plate on which the silver halide emulsion layer is coated, while maintaining the horizontal position. A method of dropping the solution and spreading the developer with a doctor bar, or a method of passing the solution through a very small processing tank in a short time and adsorbing the processing solution on the photosensitive surface can also be adopted.

In the sense of rapid processing, the amount of developer applied to a lithographic printing plate is 10 -1 per square meter of the printing plate.
The development time (time from application of the developer until the developer stops the development effect) is 15 seconds or less, preferably 2 to 10 seconds. Although the developing temperature depends on the temperature control accuracy, 20-4
It has a width of 5 ° C.

In the plate making method using a developer according to the present invention, for example, after the developer is first applied to a lithographic printing plate, the developer on the plate surface is removed with a squeezing roller or the like. Next, if necessary,
To reduce H, a neutralizing solution or washing with water is performed.
Further, in an automatic plate making machine or the like, plate making is completed through a drying step. Of course, if necessary during the plate making step, a step of heating the lithographic printing plate or the developing solution and controlling the temperature can be included.

The polyoxyethylene compounds represented by the above general formulas (4), (5) and (6) used in the present invention have an oxyethylene chain length n = 4 to 500, preferably 20.
And R is a hydrogen atom or 1-20 carbon atoms.
Is an alkyl group. 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]

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[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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[0031]

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[0032]

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[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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The amount of the above compound used in the present invention to be contained in the developer is 0.5 g / l to 80 g / l, preferably 1 g / l to 30 g.
/ l range.

Further, the developing solution of the present invention has the following general formula 26
By adding the ethylene oxide adduct of acetylene glycol represented by the formula (1), the problem caused by adding the above polyoxyethylene compound could also be solved.

[0041]

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M and n are the number of moles of oxyethylene chain added.

The problems that occur are 1) processing unevenness, processing dirt, 2) coating unevenness, and 3) generation of bubbles. In order to solve these problems, it is a usual method to use a surfactant, but there are few activators which can be stably used under a high alkali and high ionic strength like a developer. On the other hand, the surfactant itself does not have a very high solubility, which causes processing unevenness and processing stain.

The ethylene oxide adduct of acetylene glycol according to the present invention can be treated with the surfactant itself,
There was no treatment stain, and the problem caused by adding the polyoxyethylene compound could be solved.

In Formula 26, when N = m + n (total number of moles of oxyethylene chain added), the ethylene oxide adduct of acetylene glycol used in the present invention is N
= 4 to 50. Preferably, N is in the range of 6 to 20.

The amount of the ethylene oxide adduct of acetylene glycol used in the present invention is 1 liter of developer.
0.1 to 10 g per unit. The compound is commercially available, for example, from NOF Corporation or Kawaken Fine Chemical Corporation, and can be easily obtained.

The developing solution used in the present invention contains alkaline substances such as sodium hydroxide, potassium hydroxide, lithium hydroxide and sodium tertiary phosphate, and sulfites and silver complexing agents such as thiol as preservatives. Thickening agents, such as hydroxymethylcellulose, carboxymethylcellulose, etc., antifoggants, such as potassium bromide, 1-phenyl-5-mercaptotetrazole, sulfate, alkanolamine, thiocyanate, cyclic imide, thiosalicylic acid, etc. -26201, etc., and developers such as hydroquinone, 1-phenyl-3-pyrazolidone and the like.

In carrying out the DTR method, for example, British Patent Nos. 1,000,115, 1,012,476 and 1,017,
As described in the specifications of JP-A Nos. 273 and 1,042, 477, a developer is mixed into a silver halide emulsion layer and / or an image receiving layer or another water-permeable layer adjacent thereto. I have. Therefore, in such materials,
As the processing solution used in the development step, a so-called “alkaline activating solution” containing no developer can be used.

As the silver halide emulsion of the lithographic printing plate used in the practice of the present invention, silver chloride, silver bromide, silver chlorobromide, silver chloroiodide, silver chlorobromoiodide and the like can be used. Is 5
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 beam type, panchromatic type for color separation, etc. ), A gelatin hardener, a coating aid, an antifoggant, a plasticizer, a developer, a matting agent, and the like.

The binders of the silver halide emulsions include the natural and / or synthetic binders generally used for this purpose,
For example, gelatin, colloidal albumin, cellulose derivatives and the like can be used.

Under the silver halide emulsion layer (on the side of the support), a subbing layer for improving adhesion and / or an undercoat layer for the purpose of preventing halation, etc., may be included.
A matting agent may 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 and the like can be used.

The physical development nucleus used for the physical development nucleus layer is
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 disclosed in, for example, JP-B-48-29723, US Pat. No. 3,721,539.
Can be converted or enhanced to ink receptivity by the compounds described in the specification.

The printing method, the desensitizing solution, the humidifying solution, and the like to be used can be a commonly well-known method.

[0056]

EXAMPLES The present invention will be described below with reference to examples, but is of course not limited thereto. Example 1 As a lithographic printing plate utilizing the DTR method, a silver master (trade name) manufactured by Mitsubishi Paper Mills, Inc. was used. The lithographic printing plate precursor was subjected to image exposure with a plate making camera having an image reversing mechanism.

Then, in a room maintained at about 25 ° C., the lithographic printing plate subjected to image exposure was placed on a horizontal glass plate kept at a predetermined temperature (20 ° C., 30 ° C., 40 ° C.), Check that the surface temperature of the lithographic printing plate has reached a predetermined temperature with a surface thermometer (HORIBA, Ltd. IT-330),
Each of the following developing solutions was 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 thereon.

After being spread, it was allowed to stand for about 5 seconds, immediately washed with water and dried.

[0059]

[Table 1]

Compound 9 was used as the polyoxyethylene compound.

Next, these lithographic printing plates were dried and set on a Heidenberg TOK offset printing press, and the following desensitizing solution was applied all over the plate surface, and printing was performed using a humidifying solution having the following composition. Was. As the printing ink, F gloss navy blue (manufactured by Dainippon Ink and Chemicals, Inc.), which is particularly prone to appear ink stains, was used for the stain resistance evaluation.

[0062]

[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 ×; 5000 sheets or more Ink stain resistance: ；: no stain △: full or partial thin stain ×: dark stain on the entire surface

Table 3 shows the evaluation results.

[0065]

[Table 3]

Example 2 The same procedure as in Example 1 was carried out except that the following developing solution was prepared and used in place of polyoxyethylene compound 9, using chemical formulas 14, 18 and 22. I went to. However, the liquid preparation had the component amount of No. 3.

Table 4 shows the results.

[0068]

[Table 4]

From the results, it is apparent that the lithographic printing plate rapidly processed using the developer containing the polyoxyethylene compound according to the present invention has remarkably improved printing durability and ink stain resistance. In addition, the developing temperature range of the developer is
It is very effective for rapid processing that spreads to a low temperature side and the development temperature depends on the temperature of the printing plate.

Example 3 A treatment solution as shown in Table 5 was prepared.

[0071]

[Table 5]

In Table 5, as the acetylene glycol compound, a compound in which m = n = 5 in Chemical formula 26 was used.

A small processing tank (4.5 cm long, 6 mm deep) is filled with the above-mentioned processing solution, and a guide roller is placed thereon.
The plate was made to pass through the position of mm. The same printing plate as in Example 1 was passed through the small processing tank at a speed of 30 mm / min and developed.

A lithographic printing plate (20 × 40 cm) exposed to a 50% full-screen image of 133 lines was developed and processed. 1) Number of repelling of coating liquid 2) Processing unevenness: clearly visible; × faintly visible; None: O was visually evaluated.

Table 6 shows the results of the evaluation.

[0076]

[Table 6]

From Table 6, it was found that by adding an ethylene oxide adduct of acetylene glycol to the treatment liquid of the present invention, various problems occurring during coating could be solved.

[0078]

According to the developing solution of the present invention, it is extremely effective for a rapid processing and developing method, and disadvantages such as a decrease in printing durability and generation of ink stains which are observed when a developing solution of a conventional system are applied are also obtained. In addition, a large number of lithographic printing plates can be made quickly and with a small amount of developing solution.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03F 7/07 G03F 7/32

Claims (2)

(57) [Claims] 1. A developing solution used in a method of supplying a necessary developing solution and performing coating and developing in a plate making method of a lithographic printing plate utilizing a silver complex salt diffusion transfer method, wherein at least one of the following general A developer containing a polyoxyethylene compound represented by the formula: Embedded image Embedded image Embedded image n = 4 to 500, R is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. 2. The developer according to claim 1, wherein the developer for a lithographic printing plate utilizing a silver complex salt diffusion transfer method contains at least one ethylene oxide adduct of acetylene glycol.