JPH01223463A - Planographic printing plate - Google Patents

Abstract

PURPOSE:To obtain a planographic printing plate for high-illuminance and short-time exposing having high sensitivity, hard contrast and excellent preservable property by providing an intermediate layer consisting of a water permeable film formable high polymer between an emulsion layer and nucleus layer. CONSTITUTION:The intermediate layer consisting of the water permeable film formable high polymer is provided between the silver halide emulsion layer and physical development nucleus layer of the planographic printing plate for high-illuminance and short-period exposing having the emulsion layer and the nucleus layer on a base. The water permeable film formable high polymer is more particularly preferably gelatin in terms of the coating property and adhesiveness of the physical development nucleus layer. The high sensitivity to the high-illuminance and short-time exposing of a laser or the like and the high contrast are thereby obtd. and the preservable property is improved.

Description

Detailed Description of the Invention (4) Industrial Application Field The present invention relates to a photosensitive lithographic printing plate suitable for using laser light as a light source, particularly a lithographic printing plate using a silver A salt diffusion transfer method, and its products. (B) Prior art and its problems A lithographic printing plate in which a transferred silver image obtained by the silver complex salt expansion fii transfer method can be immediately used for ink receptivity has already been disclosed in Japanese Patent Publication No. 48-30562 and Japanese Patent Application Laid-open No. 30562/1989. 53-21
602, 1972-103104, 1975-9750
etc. n, is well known.

According to a typical implementation method of the silver complex diffusion transfer method suitable for the plate making method of such a lithographic printing plate, a support, a subbing layer for preventing halide swelling, a silver halide emulsion layer, and a physical development layer are formed on the support. When a gold image of a photosensitive material consisting of a core layer is exposed and developed, the silver halide forming a latent image becomes blackened silver in the emulsion layer. At the same time, silver halide on which no latent image has been formed is developed.

The silver halide complex salt, which is dissolved and diffused by the action of the silver halide complexing agent contained in the processing solution, spreads onto the surface of the photosensitive layer. It is deposited as a silver image by the action of transmitting light. In order to fully enhance the ink receptivity of the silver image obtained, the silver image is developed and, if necessary, subjected to a sensitizing treatment, after which it is placed in an offset printing press.

In the method described above, the silver halide emulsion layer is spectrally sensitized using a merocyanine dye, cyanine dye, etc. so that it has a maximum sensitivity in the green region around 55 Qnm, and the silver halide emulsion layer is spectrally sensitized using a tungsten light source. For a few seconds using a prepress camera with a normal light source such as
However, the conventional method described above had its limitations even though the lithographic printing plate originally had excellent sharpness and resolution.

Moreover, when trying to obtain color printed matter from a color original, there are problems in that not only the resolution is insufficient, but also the production of printing plates and plate-making operations are complicated. .

Today, as one method to solve the above-mentioned problems, plate making using laser light or the like has been proposed.For example, U.S. Pat. 1986-75838, 1986-
87330, 1986-100147, 1986-17
9744, 1986-103649, 1982-105
147-105150, 1982-113148, 1982-139555, 1982-141561, etc. include helium-neon laser-1 light emitting diode (LED).
), lithographic printing plates for use with argon lasers or semiconductor lasers have been disclosed.

However, lithographic printing plates for performing high-intensity, short-time exposure using a scanning exposure method, such as laser beams, suffer from poor quality, high contrast, and
The current situation is that the characteristics such as resolution, storage stability, and printing durability are still not sufficient, and further improvements are needed.
We have discovered the surprising fact that the above-mentioned properties of lithographic printing plates for exposure are dramatically improved (Q. Purpose of the Invention The purpose of the present invention is to provide high sensitivity, high contrast, and excellent storage stability. The object of the invention is to provide a lithographic printing plate for high illumination and short-time printing. A lithographic printing plate for high-intensity short-duration exposure, characterized in that there is an intermediate layer gold film made of a water-permeable film-forming polymer between the emulsion layer and the core layer. Achieved by edition n
Ta.

As the water-permeable film-forming polymer forming the intermediate layer of the present invention, gelatin is particularly preferred from the viewpoint of coatability and adhesiveness of the physical development nucleus layer. However, polymers other than gelatin, such as polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, gum arabic, can be used as polymers that can pass through the developer and have film-forming ability (i.e., water-permeable film-forming polymers). , sodium alginate, hydroxyethyl[8, dialdehyde starch, dextrin, polystyrene sulfonic acid, styrene-maleic anhydride copolymer, acrylic acid-maleic anhydride copolymer, etc. Gelatin is
Any gelatin may be used, such as lime-treated gelatin, acid-treated gelatin, and various gelatin fat conductors.

It is not clear why the uninvented intermediate layer produces effects such as sensitization and contrast enhancement. However, considering that this does not occur with low-light exposure using a normal plate-making camera, and that it does not occur even if the amount of polymer binder in the emulsion layer or physical development nucleus layer is increased without providing an intermediate layer, it is considered that high-light exposure It seems that the formation of the m-image by the process, the balance between physical development (generation, diffusion, and reduction of silver complex salts) and chemical development are intertwined and involved.

As the amount of polymer used in the intermediate layer of the present invention increases up to a certain amount, the effect of the present invention increases, but if the amount increases too much, the amount of silver transferred and deposited decreases, so the optimum amount is determined depending on the conditions. Should.

- The yield is about 0.0III to about 21 per square meter.
, preferably in the range of about o, os11 to about 1.5 g.

The intermediate layer of the present invention may contain normally required compounds such as surfactants and hardeners.The intermediate layer may be divided into two or more parts as necessary.The intermediate layer may be a silver halide emulsion. It can be applied at the same time as No. or separately.

The silver halide emulsion of the lithographic printing plate of the present invention is spectrally sensitized by a color sensitization process appropriate to the wavelength of the light source. For suitable sensitized color chips, reference may be made to the above-mentioned patent specifications.

Argon laser, helium-neon laser, CRT
For light sources such as , LED, etc., sensitizing dyes represented by -maximum (1) below are preferred.

- Maximum (I) In formula (I), 1 to R1 each represent an alkyl group, an alkenyl group, an aryl group, or an aralkyl group, and at least one of R1 and B has a sulfo group or a carboxyl group. It is a substituted alkyl group.

R1-R6 are each a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, a hydroxyl group, an alkoxycarbonyl group, a halogen atom, R1 and 84, or R3
And R6 and benzene! ' may be formed o R? i
, represents an alkyl group, an aryl group, or an aralkyl group. Y
l and Y tones are respectively n0 atom, S atom, and SsS atom N-R
, (R, is a lower alkyl group). X represents a cation such as hydrogen, an alkali metal, or ammonium. m and n represent 1 or Ot-.

All typical sensitizing dyes are listed below.

700 against half-body laser! A sensitizing dye exhibiting maximum sensitivity at 115 or higher is used. Below - maximum (6)
~N sensitizing dyes represented by M are preferred 〇-maximum (6) ~
In M, 2. and 2. may be the same or different, and each 5-membered ring represents an atomic group necessary to form a 6-membered nitrogen-containing heterocycle. R1 and B may each be the same or different, and are n-t'n alkyl groups,
Alkenyl Fund Represents. R8 represents an alkyl group, an alkenyl group, or an aryl group. R4-R1° may be the same or different, and each represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, or an alkoxy group. However, R6 and R1 or R8 and R1 can also be connected to each other to form a 5- or 6-membered 4t-. R11 and R1! may be the same or different, and each represents an alkyl group or an aryl group, and R11 and Rlm may be linked to each other to form a 5- or 6-membered box. Y has a sulfur atom, an oxygen atom, N Rta(Rts
represents an alkyl group).

Q represents the number of atoms required to form a 5-membered or 6-membered graft.

X represents an acid anion; m, n, p and q each represent t'Ll or 2;

Next, typical sensitized colors xi are illustrated.

0, H La I- v2 to 1ge -〇! Tow! The sensitizing dye used in the present invention can be synthesized by methods known to those skilled in the art. It can be added to the silver halide emulsion at any time before coating the emulsion. The additive 71at can be varied over a wide range, but good results have been obtained from 1x10 to 1x10 per mole of silver halide.
In the range of 1x10 mol. The optimum amount of addition varies depending on the conditions of the silver halide emulsion, such as the halogen composition, the average grain size of the silver halide grains, and the crystal habit.

The silver halide emulsion of the lithographic printing plate of the present invention can be silver chloride, silver bromide, silver chlorobromide, silver chloroiodide, silver chlorobromoiodide, etc., and preferably silver chloride is a halogen containing 50 mol% or more. It is chemical silver. The average particle size of these silver halide grains is preferably in the range of 0.2 to 0.8 microns, but ranges other than this can also be used. Furthermore, for silver norogenide, more than 90% of the total grain number is ±30% of the average grain size.
It is preferable that the emulsion is a monodispersed emulsion having a grain size within %0.Although silver halide having substantially cubic or tetradecahedral grains is preferable, silver halide having other crystal habits may also be used. The binder used in the silver decagenide emulsion of the lithographic printing plate of the present invention is usually gelatin. One or two hydrophilic polymer binders such as gum arabic, polyvinyl alcohol, polyvinylpyrrolidone, carboxymethyl cellulose, polyacrylamide, styrene-maleic anhydride copolymer, polyvinyl methyl ether-maleic anhydride copolymer, etc.
It can also be replaced with more than one building. Furthermore, an aqueous vinyl polymer dispersion (latex) can also be used.

Silver halide emulsions can be sensitized in a variety of ways when they are manufactured or coated. Preferably, it is chemically sensitized by methods well known in the art, such as by sodium thiosulfate, alkylthioureas, or by gold compounds such as rhodan gold, gold chloride, or a combination of both.

In addition, by using compounds of metals belonging to Vlhyc of the periodic table, such as salts of cobalt, nickel, rhodium, palladium, iridium, platinum, etc., at any stage in the production of silver halide emulsions, particularly high sensitivity can be achieved. It is possible to obtain characteristics desirable for a printing plate for direct plate making with high sharpness and high resolution. The amount added is in the range of 10 to 10 moles per mole of silver halide. The silver halide emulsion layer can contain other additives, such as coating aids, hardeners, anti-capri agents, matting agents (water retention agents), lump-method herbal medicines, and other conventional additives.

1N below the silver halide emulsion layer! An undercoat layer for improving adhesion or a subbing layer that may contain a light-absorbing compound such as carbon black can be provided on the IC support (I C support). It can also contain agents.

A photosensitive lithographic printing plate using the DTR method has an image-receiving layer containing physical development nuclei. Such an image-receiving layer can also be provided below the silver halide emulsion layer, and after image exposure the DT
After R development, the silver halide emulsion layer and intermediate layer are removed to obtain a lithographic printing plate. The image-receiving layer is particularly preferably provided above the silver halide emulsion layer, that is, as the outermost surface layer via an intermediate layer.

As physical development nuclei, known ones such as metals such as antimony, bismuth, cadmium, cobalt, palladium, nickel, silver, lead, and zinc and their sulfides are used. The image-receiving layer contains hydrophilic colloids such as gelatin, carboxymethyl cellulose, gum arabic, sodium alginate, hydroxyethyl starch, dialdehyde starch, dextrin, hydroxyethyl cellulose, polystyrene sulfonic acid, a copolymer of vinylimidazole and acrylamide, and borivinyl alcohol. It may contain one type or two or more types. In the case of a lithographic printing plate having an image-receiving layer as a surface layer, the water-soluble colloid contained in the image-receiving layer is 0.
．． It is preferably 517 m' or less.

Hygroscopic substances such as wetting agents such as sorbitol and glycerol may be present in the receiver 12 layer ◇Furthermore, the receiver + Jj! The layer may also contain pigments for preventing scumming such as barium sulfate, titanium dioxide, china clay and -, a developing system such as hydroquinone, and a hardening agent such as formaldehyde or dichloro-8-)riazine.

The support may be, for example, paper, film such as cellulose acetate film, polyvinyl acetal film, polystyrene film, polypropylene film, polyethylene terephthalate film, or a composite film in which polyester, polypropylene, or polystyrene film is coated with polyethylene film, metal, or metal. It can be a support of synthetic paper or metal/paper laminate. Paper supports coated on one or both sides with an alpha-olefin polymer, such as polyethylene, are also useful. These supports include
A compound capable of preventing Halesi's tumor may be mixed.

The block method treatment solution used in the present invention contains alkaline substances such as sodium hydroxide, potassium hydroxide, lithium hydroxide, tertiary phosphate, etc., and sulfur as a preservative.
! salts, silver halide solvents such as thiosulfur m,4, thiocyanates, cyclic imides, thiosalicylic acid, amines, etc., thickening agents such as hydroxyethylcellulose, carboxymethylcellulose, antifoggants such as potassium bromide, l-phenyl -5-mercaptotetrazole, a compound described in JP-A No. 47-26201, a stock agent such as hydroquinone, l-phenyl-3-pyrazolidone, a developer modifier such as a polyoxyalkylene compound, an onium compound, etc. can be included.

For implementing the silver complex diffusion transfer method, for example, British Patent No. 1,000,115, GL, 012,476,
ml, No. 017,273, No. 1,042,477, etc., a developer is incorporated into the silver halide emulsion layer and/or the image receiving layer or other water permeable layer adjacent thereto. Mixing is being done. Therefore, in such materials, the processing used in the development stage is limited.
I-liquid is a so-called "alkaline activation liquid" that does not contain any active agents.
can be used.

The lithographic printing plate manufactured according to the present invention is, for example,
8-29723, US Vat￥jff No. 3,721,53
The ink receptivity can be changed or enhanced by compounds such as those described in No. 9 and others.

The printing method, the desensitizing liquid used, and the moisture supply can be determined by commonly known methods. It is not something that will be done.

Example 1 A matting layer containing silica particles with an average particle size of 5 μm was provided on one side of a subbed-treated polyester film support, and carbon black was provided on the other side to provide a 20% ]it% of silica powder with an average particle size of 7jm (adjusted to pH 4.0) and silica powder with an average particle size of 7μm on photographic gelatin after being chemically sensitized with hypo and gold compounds. A spectrally sensitized high-sensitivity silver chloroiodobromide emulsion layer (Br3
pH at mol%, 10.4 mol%, 0J96.6 mol%
(adjusted to 4°0).

Gelatin without undercoat is 3.0 g/m", gelatin in the emulsion layer is 1.oy/m", silver halide converted to silver nitrate is 1.
．． The undercoat and emulsion layers were made with formalin as a hardening agent at a ratio of 5.0% to gelatin.
gy/J? Contains gelatin value. After drying, 4
After heating at 0°C for 14 days, JP-A-53-216020 English Example 2. A lithographic printing plate is prepared by using the nuclear blood described in 1. (the polymer is a 1:3 copolymer of acrylamide and imidazole, containing hydroquinone at a ratio of 0° sy/mF) as a blood cloth and drying it. The silver halide emulsion is a physically aged IIK silver halide emulsion containing 5Xlυ mol rhino rhodium chloride per mole of silver halide, with an average grain size of 0°35 microns, ±30% of the average grain size.
It was a substantially cubic crystal with more than 90% of the total number of particles distributed in the range of .

In addition, 5 x 10 mol of exemplified dye (10) was added as a sensitizing dye per 1 mol of silver halide (comparison a), while
In the lithographic printing plate of comparison a, lime-treated gelatin 0.11
7 m'' (invention B), 0.211/rrr'' (invention B
), a lithographic printing plate A-0 of the present invention was produced in the same manner except that an intermediate layer of 0.411/A (invention 0) was coated together with the emulsion layer and the undercoat layer. The intermediate layer contained a hardening agent and a surfactant, and the pH was adjusted to 4.5.・These lithographic printing plates are processed using semiconductor laser exposure equipment (U.S.
The image was exposed using Ultra matter (manufactured by LTRE), and this was used as a sample for a printing test.

On the other hand, attach a dark red filter (so-70) to the light source,
The lithographic printing plate was subjected to internal light exposure for 10 seconds through a light pipe to prepare a sample for sensitometry.

After exposure, development was performed using the following diffusion transfer developer.

After processing with a transfer developer, the original plate is passed between two squeezing rollers to remove excess developer. After removing the liquid, immediately treat it with a neutralizing liquid having the following composition at 25°C for 20 seconds, and remove any excess with a squeezing roller. i
n was removed and dried at room temperature.

Neutralization if> Table 1 shows the sensitivity and printing durability of each lithographic printing plate. The sensitivity is expressed as a relative value, with the comparative printing plate a being 1.0 based on the j1 element amount required to stop the formation of transferred deposited silver. The printing durability was determined by pasting each sample onto a sheet, attaching this sheet to an offset printing machine, applying the following desensitizing liquid all over the plate surface, and printing using the following dampening liquid. Ta. The printing machine is N.B.Dick 3500D (
The printing durability was evaluated based on the number of sheets that could not be printed due to the occurrence of background smearing or silver staining using A. Shown in the right column.

Rating: 1.4.00 (3 or less sheets 2. 4,000-6,000 sheets 3. 6,000-s, ooo sheets 4. 8,000-10,000 sheets 5, 10,000 sheets or more) Humidifying liquid〉 Humidifying liquid〉 Table 1 The lithographic printing plates of the present invention A to 0 have higher contrast (particularly good sharpness at the foot portions) and higher sensitivity than the lithographic printing plates of the comparatively hot type. The printing durability is also good.Furthermore, after storing these lithographic printing plates under conditions of 50°C and 80% RH for 5 days,
When a sensitometric test was similarly conducted, it was found that the lithographic printing plate of Comparative A had a 40% desensitization, whereas the present invention ^
, B and 0 had desensitization of 25%, 20% and 10%, respectively, and were found to have good storage stability.

Example 2 During the production of silver halide, 3XlO-' mol of hexachloroiridium J and potassium chloride were added per mol of silver halide to prepare a layered silver emulsion having an average grain size of 0.4 microns.

Comparison of lithographic printing plates prepared in the same manner as in Example 1 except that 3 x 10 mol of exemplary color $(3) was added as a sensitizing dye per mol of silver halide and a polyethylene laminate paper support was used. It was quiet.

On the other hand, in the comparative lithographic printing plate, there were 0.217 m'' (invention D), o, 7 m'' (invention E), o, stp 7 m'' (invention F) between the emulsion layer and the core layer. Lithographic printing plates provided with a lime-treated ceratin intermediate layer according to Example 1 were prepared according to the present invention and designated as B and F.

These lithographic printing plates were exposed to flash light for 10 seconds and developed according to Example 1, and the sensitivity and gradation were examined. As a result, the sensitivity of the comparison plate was 1.0, the sensitivity of the invention plate was 1.3, and the sensitivity of the invention plate was 1.3. B is 1.
6. Invention F- had a sensitivity of 2.1, and Invention D-F both had higher contrast than in comparison.

This result was also confirmed by scanner exposure with a helium-neon laser.

(F5 Effects of the Invention The lithographic printing plate of the present invention has high sensitivity and high contrast to high-intensity short-time exposure such as laser, and also has improved storage stability.

Claims (1)

[Claims] (1) A lithographic printing plate for high-intensity short-time exposure having at least a silver halide emulsion layer and a physical development nucleus layer on a support, in which a water-permeable film is formed between the emulsion layer and the nucleus layer. A lithographic printing plate characterized by having an intermediate layer made of a polymer.