JPH1184669A - Production of lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily produce a lithographic printing plate with excellent printing characteristics by a dry method without using water by heat developing a heat developable silver salt photosensitive element and physical development nuclei in a contact state without using water. SOLUTION: A heat developable silver salt photosensitive element and physical development nuclei in a contact state are heat developed without using water. The heat developable silver salt photosensitive element has an oxidation- reduction image forming component comprising a reducible org. silver salt and a reducing agent, a photosensitive silver halide and/or photosensitive silver halide forming component, and a binder on a supporting body. The physical development nuclei are formed as a physical development nuclear layer on the heat developable silver salt photosensitive element to make a contact state with the element, or formed as a physical development nuclear layer on another supporting body. For example, after the heat developable silver salt photosensitive element carrying the physical development nuclei on its surface is exposed according to an image, the element is heated at least at 70 deg.C for several seconds to several minutes to produce physically developed silver in the unexposed area by the effect of the physical development nuclei as a catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for preparing a lithographic printing plate, and more particularly to a method for preparing a lithographic printing plate by a dry (dry) method.

[0002]

2. Description of the Related Art A lithographic printing plate in which a transferred silver image obtained by a silver complex salt diffusion transfer method (DTR method) can be immediately used as ink receptivity is well known. For example, a planographic printing plate having a silver halide emulsion layer and a physical development nucleus layer on a support is disclosed in JP-B-48-30562,
Nos. 3-9603, 53-21602, 54-10
JP-A-5-216 discloses a lithographic printing plate having a silver halide emulsion layer on a physical development nucleus supported on an aluminum support.
236 and 6-81194.

According to the method of making a lithographic printing plate, DT
When processed with an R developing solution, the silver halide on which a latent image is formed becomes blackened silver in the emulsion layer. At the same time, the silver halide on which no latent image is formed is dissolved by the action of the silver halide solvent contained in the developing solution and diffuses into the physical development nucleus layer. The dissolved and diffused silver complex is deposited as image silver by the reducing action of the developing agent using the physical development nucleus as a catalyst, and the deposited silver is used as ink receptivity.

Although the lithographic printing plate making method has many advantages, it is susceptible to, for example, processing conditions due to wet development processing, which makes it difficult to design lithographic printing materials and processing solutions. Accompany. Further, the user is troublesome in maintenance and management of the processing apparatus and the processing liquid, and management of waste liquid is also a problem from an environmental point of view. In recent years, there has been a demand for environmental measures (reduction of the amount of waste liquid) and improvement in maintainability of a processing apparatus, and a coating processing method capable of processing with a small amount of processing liquid has been developed (for example,
(See JP-A-4-307245, JP-A-6-27682, and JP-A-7-175219), which is hardly a fundamental solution.

JP-A-8-314143 and JP-A-8-31
No. 4144 discloses a method for preparing a lithographic printing plate which is subjected to heating DTR development using a small amount of water, an alkali generator and a silver halide solvent. This method has a problem that, unless a small amount of water is supplied uniformly, unevenness of the transferred silver image, and eventually unevenness of the printed image, is likely to occur.

[0006] On the other hand, methods for producing printing plates that are heat developable are also known. For example, Research Diss
Closure No. 33303 (1992)
Disclosed is a thermosensitive image-forming material having cross-linked hydrophilicity on a support containing thermoplastic polymer particles and an infrared absorbing pigment (for example, carbon black). Upon image-wise exposure with an infrared laser, the thermoplastic polymer particles coagulate image-wise and become ink-receptive. The disadvantage of this method is that
When pressure is applied to a non-printing area, the ink receiving property, that is, the background is easily stained, and lithographic printing performance is not sufficient.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a simple method for preparing a lithographic printing plate excellent in printing characteristics by a dry method that does not use water without the above-mentioned drawbacks in wet processing. That is.

[0008]

The above objects of the present invention can be attained by subjecting a heat-developable silver salt light-sensitive element to physical development nuclei in a contact state and performing heat development without using water.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The heat-developable silver salt photosensitive element used in the present invention comprises, on a support, at least (a) an oxidation-reduction image forming component comprising a reducible organic silver salt and a reducing agent;
(B) a photosensitive silver halide or (and) a photosensitive silver halide forming component, and (c) a binder.

The physical development nucleus used in the present invention may be provided as a physical development nucleus layer on the heat-developable silver salt light-sensitive element, or may be provided on a separate support. Provided as a layer.

Heat-developable silver salt light-sensitive elements are known, for example, JP-B-43-4924 and JP-B-52-17415.
JP-A-53-2687, JP-A-59-282895, and JP-A-48-97523.

(A) The reducible organic silver salt as an oxidation-reduction image forming component is preferably a silver salt of a long chain fatty acid having 12 to 24 carbon atoms, for example, silver behenate, silver stearate, palmitic acid Silver, silver myristate, silver laurate,
Although silver oleate and the like can be mentioned, silver behenate is particularly useful.

(A) Various reducing agents can be used as the oxidation-reduction image forming component. Generally, developing agents used in ordinary silver halide photosensitive materials, specifically, hydroquinone, methylhydroquinone, chlorohydroquinone, methylhydroxynaphthalene, diethylamino-p-phenylenediamine, aminophenol, ascorbic acid, 1-phenyl -3-pyrazolidone, 2,2'-methylenebis (6-t-butyl-
4-methylphenol, 4,4'-butylidenebis (6-
t-butyl-3-methylphenol, 4,4'-thiobis (6-t-butyl-3-methylphenol and the like can be mentioned.

(B) As the photosensitive silver halide, silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodide and silver chlorobromoiodide can be used. The photosensitive silver halide is preferably in the form of fine particles. As a preparation method, a part of the reducible organic silver salt is converted into a silver halide forming component, for example, ammonium bromide,
A method of preparing a fine silver halide by halogenating with lithium bromide, sodium chloride, N-bromosuccinimide or the like can be given. Further, a method of containing a so-called extra-system silver halide can also be used.

The heat-developable light-sensitive element containing the extra-system silver halide is described in, for example, Belgian Patent No. 774436. That is, a photosensitive silver halide is prepared outside the heat-developable photosensitive element, in other words, outside of the oxidized-reduced image forming component, and then the silver halide is added to the image forming component and mixed. Prepared. The suitable content of silver halide (or silver halide forming component) is preferably 0.001 mol to 0.3 mol, particularly preferably 0.01 mol to 0.15 mol per mol of the reducible organic silver salt. Range of moles.

The photosensitive silver halide may be chemically sensitized, and may be used as an exposure light source, for example, a He—Ne laser, a red L
Spectral sensitization can also be performed according to a desired light source wavelength such as a D laser or an infrared LD laser.

The heat-developable silver salt photosensitive element used in the method of preparing a lithographic printing plate of the present invention contains (c) a binder alone or in combination in a layer. Suitable materials for the binder can be hydrophobic or hydrophilic, and can be transparent or translucent. Specifically, polyvinyl butyral, cellulose acetate butyrate,
Polymethyl methacrylate, polyvinylpyrrolidone,
Ethyl cellulose, cellulose acetate, polyvinyl acetate,
Polyvinyl alcohol, gelatin, Canadian Patent No. 774
No. 054 having a sulfobetaine repeating unit. The amount of the binder used is 10: 1 to 1: by weight based on the organic silver salt to be reduced.
10 is preferred, and more preferably in the range of 4: 1 to 1: 2.

The physical development nuclei used in the present invention include:
Zinc, cadmium, lead, iron, nickel, tin, cobalt,
Conventionally known heavy metals such as copper, noble metals such as palladium, platinum, silver, and gold, and sulfides, selenides, and tellurides of these metals can be used. These physical development nuclei reduce the corresponding metal ion to form a metal colloid dispersion, or mix a metal ion solution with a soluble sulfide, selenide or telluride solution to form a water-insoluble metal sulfide, It is obtained by making a colloidal dispersion of metal selenide or metal telluride.

The physical development nucleus is supported on the upper part (surface) or in some cases lower part (between the support and the photosensitive layer) of the heat-developable silver salt light-sensitive element, or separately from the heat-developable silver salt light-sensitive element. On a support. The latter is preferred in terms of printing characteristics. The loading amount of the physical development nucleus is usually 10 ⁻⁵ to 10
^-1 g / m ² .

It is generally preferable to provide a physical development nucleus layer by coating as a colloid solution,
Other methods, such as a method of dipping in a colloid solution, may be used. Physical development nucleus colloid solution, a binder, for example, gelatin, polyvinyl alcohol, polyvinylpyrrolidone, various cellulose derivatives, acrylamide polymer,
It may contain starch and the like. When a binder is contained, the content is preferably 300% by weight or less based on the physical development nucleus.
When a physical development nucleus layer is provided on the heat-developable silver salt photosensitive element used in the present invention, silicon dioxide (silica), starch, polymethyl methacrylate and the like have an average particle diameter of 1%.
It is preferable to provide a physical development nucleus layer containing a matting agent of about 10 to 10 μm.

The heat-developable silver salt photosensitive element used in the present invention can be obtained by forming a coating on a suitable support. As the support, polyethylene, polypropylene,
Synthetic resin film such as polyethylene terephthalate, polycarbonate, cellulose acetate, etc., synthetic paper, paper coated with synthetic resin film such as polyethylene, paper such as art paper, baryta paper for photography, etc., or metal plate (foil) such as aluminum And a synthetic resin film or a glass plate on which a metal deposition film is formed by an ordinary method. When a physical development nucleus is provided on a heat-developable silver halide photosensitive element,
Since the photosensitive element is a planographic printing plate, one that satisfies at least the physical properties of the printing plate is selected. When provided on a support different from the heat-developable silver salt light-sensitive element, the support becomes a lithographic printing plate, and thus the same physical properties are required.

The heat-developable silver salt light-sensitive element used in the present invention may be an antifoggant such as a 1,2,4-triazole compound described in JP-B-55-42375.
No. 7,308,828, benzoic acids described in JP-A-57-138630, compounds having a sulfonylthio group described in JP-A-57-147627, and JP-A-58-107534. The dibasic acids described may be contained. Further, a development accelerator, for example, an alkali metal salt compound of a fatty acid described in JP-B-64-8809 can be contained.

The heat-developable silver salt light-sensitive element used in the present invention comprises a fluorine-containing surfactant as an antistatic agent or a fluorine-containing surfactant described in JP-A-64-24245 and a nonionic surfactant. A surfactant may be used in combination. Further, the above-mentioned matting agent can be contained.

In the method of preparing a lithographic printing plate according to the present invention, for example, after imagewise exposing a heat-developable silver salt photosensitive element having a physical development nucleus supported on its surface, a temperature of at least 70 ° C. for several seconds to several minutes, preferably 90 ° Heating is performed at about 200 ° C. for about 1 to 200 seconds to generate physically developed silver in the non-exposed area using the physical development nucleus as a catalyst. In the case of a sheet carrying physical development nuclei on another support, after imagewise exposing the heat-developable silver salt photosensitive element, the same heating is performed while closely contacting the sheet,
Physically developed silver is formed on the sheet.

In the heat development method of the present invention, in order to form a silver image in a photosensitive layer corresponding to an exposed portion of the heat-developable silver salt photosensitive element, for example, heating is performed at 100 to 140 ° C. for 1 to 50 seconds, Thereafter, the heating temperature is higher than the above-mentioned heating condition, and further, a long-time strong heating condition, for example, 130 to 200 ° C. and 5 to 2
A method of performing reheating for 00 seconds to promote physical development from the photosensitive layer corresponding to the non-exposed area can also be adopted.

Heat development may be performed by any method such as heating with a hot roll, heating on a hot plate, heating in silicone oil, and heating with hot air. Heating without using water means that not only water but also a liquid such as an alkali developing solution is not used.

The lithographic printing plate obtained according to the present invention is treated with a commercially available etchant for a DTR lithographic printing plate (containing a heterocyclic compound having a mercapto group as a lipophilic agent) to form an ink. It is preferable to enhance acceptability, and printing conditions such as fountain solution and ink can be determined by a commonly used method.

[0028]

Hereinafter, the present invention will be described with reference to Examples.
The present invention is not limited to these.

Example 1 (Preparation of photosensitive silver halide) Under red safety light, 11.0 g of silver stearate was dispersed in 200 ml of ethanol, and 7.5 g of polyvinyl butyral was further added and stirred and dissolved. While maintaining the obtained silver stearate dispersion at 50 ° C. and stirring, 50 ml of an acetone solution in which 5.5 g of N-bromosuccinimide and 6.4 mg of sodium bromide were dissolved was added.
It was dropped over time. After completion of the dropwise addition, the mixture was further stirred at 50 ° C. for 1 hour, and then cooled to room temperature to prepare a silver bromide dispersion.
This silver bromide dispersion is dropped into 1,000 ml of vigorously stirred water, the precipitate is filtered, dried, and a silver bromide-polyvinyl butyral solid containing stearic acid (hereinafter referred to as a silver bromide solid). Was prepared.

(Preparation of heat developable silver salt photosensitive element) A photosensitive composition having the following constitution was prepared. Silver pehenate 25 g Silver bromide solids 4.15 g Pehenic acid 18 g 2,2-Methylene-bis- (6-t-butyl-4-methylphenol) 20 g Phthalazine 6.0 g 20% mercuric bromide in 20% methanol 5ml xylene / butanol (volume ratio 1/1) 1000ml

This was coated on a 100 μm-thick polyester film and dried to form a 10 μm-thick photosensitive layer.

Then, a palladium sulfide nucleus solution containing polyvinyl alcohol as a binder was prepared in accordance with the physical development nucleus A described in Examples of JP-A-56-27151, and silicon dioxide (silica) having an average particle diameter of 1.3 μm was prepared. ) A matting agent was added in an amount of 0.4 g / m ^2, and then coated and dried on the above-mentioned photosensitive layer to prepare a heat-developable silver salt photosensitive element serving as a printing plate precursor.

The resulting heat-developable silver salt photosensitive element was exposed to tungsten light using a light source and an exposing machine and subjected to heat development at 140 ° C. for 30 seconds. Was precipitated.

After the lithographic printing plate was wiped with a silver master etchant (SLM-OH), the plate surface was set on an offset printing machine (AB-Dick 365; a trademark of an offset printing machine manufactured by AB-Dick), and the ink was AB-D
Printing was performed using an ink 3-1012 black ink and a dampening solution for silver master (SLM-OD). A large number of prints with little background stain and good ink density could be obtained.

Example 2 The silicon dioxide was removed from the physical development nucleus solution of Example 1 and applied to an anodized and roughened aluminum support. The heat-developable silver salt photosensitive element having no physical development nucleus layer of Example 1 was similarly exposed, and the photosensitive layer and the nucleus layer of the aluminum support were heated from both sides while sandwiched between two hot plates in a state where the nucleation layer was in close contact with the photosensitive layer. And developed. A mirror-finished silver image was obtained on the physical development nucleus layer. When printing was performed in accordance with Example 1 below, a larger number of printed matter having better quality than in Example 1 could be obtained.

[0036]

By combining a heat developable silver salt photosensitive element with a physical development nucleus, a good lithographic printing plate can be obtained by a dry method without using water or an alkali developing solution.

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI G03F 7/26 521 G03F 7/26 521

Claims (1)

[Claims] 1. A method for preparing a lithographic printing plate, comprising heating and developing a heat developable silver salt photosensitive element and a physical development nucleus in contact with each other without using water.