JPS61173254A - Production of negative type lithographic printing plate - Google Patents

Abstract

PURPOSE:To form a negative type lithographic printing plate which is free from fogging, has high sensitivity and high contrast and is excellent in a metallic image forming speed and efficiency by incorporating an electron donative compd. which has low oxidation potential in a buffer soln. having specific pH into a photosensitive photographic element. CONSTITUTION:This printing plate contains the electron donative compd. having the oxidation potential lower than the oxidation potential of a compd. (SRR compd.) which releases a compd. which acts as a dissolving agent for metallic salt particles having no sensitivity or a dissolved matter developing accelerator by reacting with the developing agent oxidant formed by development in the buffer soln. (25 deg.C) having 13.0pH. The more preferable embodiment of the electron donative compd. is exemplified by a compd. such as substd. hydroquinone having low oxidation potential in an aq. alkaline soln., i.e., having a reducing characteristic. The SRR compd. expressed by the formula is used as an example of said compd.

Description

Detailed Description of the Invention 1. Background of the Invention Technical Field -1-- The present invention relates to a method for producing a negative planographic printing plate using a novel negative silver smoke diffusion transfer image forming method.

Prior art and its problems A method is already widely known in which a silver image is formed using a silver salt diffusion transfer method, and the silver image is subjected to a sensitization treatment to be used as a lithographic printing plate.

That is, in the above method, the silver halide coated on the support is exposed to light and then treated with a developer and a silver halide solvent to convert the silver halide in the exposed area into reduced silver. The silver halide in the unexposed area is dissolved by the action of a silver halide solvent and deposited as physically developed silver on the adjacent physical development nuclei, and the positive silver image thus obtained is further exposed to light. The technology for fat conversion is described in detail in No. 18719 or No. 48-30562.

However, all of the printing plates obtained by the method for producing a lithographic printing plate using the above-mentioned diffusion transfer method are positive printing plates and cannot be used when producing a lithographic printing plate directly from a negative original.

Furthermore, in direct plate making using a laser scanner, which has recently begun to be widely used, a negative type is theoretically more advantageous than a positive type.

On the other hand, little is known about the manufacturing method of lithographic printing plates using the negative silver salt diffusion transfer method, and as a slightly more recent example, Japanese Patent Application Laid-open No. 57-44153 describes photosensitive halogenation of exposed areas. A method is described in which the physicochemical action caused by silver development dissolves the easily soluble metal salt particles, which have been rendered insensitive to light, to form a metal image on the physical development nucleus, and sensitizes this. Furthermore, Japanese Patent Application Laid-Open No. 57-150849 describes an improved method of the above method, but since all of the above methods use metal salt particles that have been treated to make them difficult to dissolve, as negative image forming materials,
It has the disadvantage that the speed of image formation during development processing is slow, and that the photosensitive material contains a large amount of a metal salt refractory agent, which adversely affects its storage stability.

Therefore, the present inventors have developed a method for producing a negative planographic printing plate that does not have these drawbacks, has a short processing time, and has excellent transfer efficiency of metal salt particles to an image. 2> Metal salt particles that have substantially no photosensitivity. <3> Reacts with the oxidized developing agent produced during development and acts as a dissolving agent or dissolved physical development accelerator for the metal salt particles mentioned in <2> above. Compounds that release compounds (AgX
5olvent Releasing Redox
Compounds.

(hereinafter abbreviated as SRR compound) <4> A compound containing physical development nuclei was proposed (Japanese Patent Application No. 59-54089).

This negative-tone sensitive material is processed with a developing solution containing a metal salt particle reducing agent to cause the development of the photosensitive silver halide described in <1> above in the exposed areas, and the effect of the oxidized product of the developing agent produced. An image is obtained by depositing the metal ions or metal complex ions generated from <2> and <3> above as metals on the physical development nuclei of <4>.

This method has the above-mentioned advantages and is also excellent in storage stability, but because development is amplified, even a small amount of oxidized developing agent may exist in the system due to air oxidation. It also had the disadvantage of easily producing capri.

(2) Purpose of the Invention The object of the present invention is to provide a novel method for producing a negative planographic printing plate that is free from such fog, has high sensitivity and contrast, and is excellent in metal image forming speed and efficiency.

■ Structure of the invention Structure and principle of the present invention The present invention consists of (1) photosensitive silver halide, (2)
metal salt particles having substantially no photosensitivity; (3) reacting with the oxidized developing agent produced during development;

A photosensitive photographic element containing a combination of a compound that releases a compound that acts as a solubilizer or a dissolved physical development accelerator, and (4) physical development nuclei is subjected to imagewise exposure and then development processing. In the method for producing a negative planographic printing plate, the method includes the step of selectively depositing the metal salt particles of the above (2) in the exposed area on the physical development nuclei of the above (4) as a metal image, wherein p
An electron donating compound (E) which has a lower oxidation potential than the compound (3) in a buffer solution (25°C) of H=131)
A method for producing a negative lithographic printing plate, which is characterized by comprising the steps of:

That is, when the photosensitive photographic element of the present invention is imagewise exposed and then developed, development of the photosensitive silver halide () occurs in the exposed areas, producing an oxidized developing agent (
3) by reacting with a compound that releases a compound that acts as a dissolving agent or dissolving physical development accelerator for metal salt particles (2).
A negative-like metal image is deposited on the physical development nucleus of (4) by dissolving or dissolving the metal salt particles of (4), but this image usually forms a dense metal aggregate layer with a specular surface. and has ink receptivity. On the other hand, in the valve exposed area, pH = 12.0 to 14, which is the normal development processing condition.
．． Since the electron donating compound (El), which has a lower oxidation potential than the compound (3) in 0, contains a suitable amount, a small amount of the oxidized developing agent produced by air oxidation, etc. reacts selectively with (El). (3)
) does not react with the compound, so no fogging occurs.

In addition, since the amount of oxidized developing agent produced in the exposed area is large, the initiation of the reaction of the compound (3) is not prevented, and therefore the amplification effect of development is almost the same as in the case without fE). The above processing renders the photographic elements of the present invention suitable for use as negative-working lithographic printing plates.

In addition, the photosensitive photographic element of the present invention not only achieves the above-mentioned objectives, but also has excellent metal transfer efficiency to physical development nuclei, so when non-photosensitive silver halide is used as the metal salt particles, This has advantages such as the ability to save on silver.

Components of the invention A buffer solution (pH=13.0 at 25°C) used in the invention
), the electron donating compound (E) having a lower oxidation potential than the compound (3) can be a variety of compounds depending on the selection of the compound (3) to be used, but preferred examples include substituted compounds. 1 with various substituents such as hydroquinone, substituted catechol, alkyl, allyl, alkoxy, etc.
Compounds having so-called reducing properties, such as 4- or 1,2-dihydroxynaphthalene, substituted aminophenols, and substituted phenylene diamines, have a low oxidation potential in alkaline aqueous solutions. These compounds may also be substituted with ballast groups for immobilization in photographic elements.

As a more specific example, when the below-mentioned 5RR-1 is used as the compound (3), the following compounds are preferably used as (E), but the present invention is not limited thereto.

2. OH 3, OH 4, OH OH 5, OH OH CH3 Oxidation half-wave potential EX (Ox) of compounds 1 to 10 is pH
The measurement was carried out using a cyclic portammetry method in a buffer solution (25° C.) of 13.0° C. using a saturated calomel electrode as a reference electrode. The sample concentration at the time of measurement was 10-3 to 10-4 mol/a.

These compounds are 0.0 per mole of compound (3)
It is used in a range of 1 to 100 moles.

Further, these compounds may be used alone or in combination.

The photosensitive silver halide (1) used in the present invention includes silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodide, silver iodobromide, silver chloroiodobromide, or these. Although a mixture or the like may be used, preferably a highly sensitive silver bromide or an iodobromide diode containing 10 mol % or less of silver iodide is suitable for the present invention. Further, the photographic emulsion containing silver halide in the present invention is prepared by a conventional manufacturing method. Further, the silver halide grains used in the present invention include those having various crystal habits. This silver halide emulsion can be sensitized using various salt-sensitive materials, it can also be spectrally sensitized using a sensitizing dye to impart photosensitivity to a desired spectrum region, and it can also be sensitized using various stabilizing dyes. It can also be stabilized using a stabilizing agent.

The non-photosensitive metal salt particles (2) used in the present invention are (
The dissolution rate of the metal salt particles released from the compound (3) in the dissolving agent is higher than that of the photosensitive silver halide (1), and the compound is a metal salt having substantially no photosensitivity.

In the present invention, "substantially not having photosensitivity" means not being photosensitized relative to the photosensitive silver halide in (1) above, and specifically, (1
This means that when the light energy necessary to sensitize the light-sensitive silver halide of ) is applied to the light-sensitive photographic element according to the present invention, it is not substantially exposed to light at that light energy. In the present invention, the term "non-photosensitive-1" is also used synonymously.

The non-photosensitive metal salt particles (2) used in the present invention may be selected from those having the above-mentioned properties, but in a preferred embodiment of the present invention, the non-photosensitive metal salt particles (2) are substantially photosensitive. These silver halide grains have a higher dissolution rate in a dissolving agent than the photosensitive silver halide grains described in (1) above. It will be done.

More specifically, the metal salt particles preferably applied to the present invention are pure silver chloride that has not been subjected to chemical sensitization treatment or salt odor particles that have been subjected to desensitization treatment and contain 5 mol% or less of desensitized silver. Silver chloride, silver chloroiodide containing 1 mol% or less of silver iodide, or a mixed silver halide thereof, which preferably has finer crystals than the photosensitive silver halide described in (1) above; The metal salt particles are used in an amount of 0.1 mol to 100 mol, preferably 1 mol to 10 mol, per 1 mol of photosensitive silver halide in (1).

The compound (3) that releases a solubilizing agent or a dissolved physical development accelerator (SRR compound) used in the present invention means a compound represented by the following general formula. .

A-B(1) [1] In the formula, A is a redox mother that is oxidized by cross-oxidation with an oxidized developing agent and releases B residues by a subsequent hydrolysis reaction under alkaline conditions. A nucleus is formed, and B forms a substituent which, when eliminated from A, forms a compound that exhibits a metal salt particle dissolving action or a dissolution physical development promoting action. A may have a ballast group attached to it to immobilize it in the photographic element. Here, A is preferably a negative-acting dye-releasing redox compound commonly known in color diffusion transfer processes.
singRedox Compounds, hereinafter DR
The redox nucleus of R compound (abbreviated as R compound) is used.

More specifically, substituted phenols, substituted naphthols, substituted indoles, etc., which are bonded to B via a sulfonamide group, as shown in formulas 0 to 0, are preferably used as A.

αNH30□- In the formula, α represents a hydroxyl group or a group that gives a hydroxyl group by hydrolysis, β represents an atomic group necessary to form a carbocyclic ring, for example, a benzene ring, and a carbocyclic or heterocyclic ring is added to the benzene ring. The rings may be fused to form, for example, a naphthalene ring, a quinoline ring, or the like. r represents an alkyl, alkoxy or aryl substituent, and Ba1l represents an organic ballast group, preferably a group containing a hydrophobic group having from 8 to 50 carbon atoms. In the compound (2), a ballast group may be substituted at the r position.

The mechanism of B residue release by development is the same as the mechanism of dye release of DRR compounds in color diffusion transfer method, and Anq
eHChem, Int, Ed, Engl, 2
It is described in detail in reviews such as Vol. 2, pp. 191-209 (1983) or Organic Synthetic Chemistry, Vol. 39, No. 4, pp. 331-334 (1981). As the B residue, a substituent that forms a compound that exhibits a metal salt particle dissolving action or a dissolution physical development promoting action, which is known in the field of photographic light-sensitive materials, is usually used, but more preferably a redox mother of the DRR compound. In addition to heterocyclic compounds such as substituted uracil, substituted hydantoin, substituted imidazolidinethione, fitted-substituted thiazolidinethione, and substituted oxazolidinethione, which are bonded to the nucleus through a sulfonamide group, chain-like substituted thioethers, substituted amino alcohols, etc. Conventionally, compounds known as silver halide solvents or silver halide dissolution physical development accelerators are used in the field of TA salt light-sensitive materials.

The following compounds are used as examples of the SRR compound (1).

SRR-1゜5RR-2゜5RR-4゜5RR-5゜5RR-6゜5RR-8゜5RR-9,5 The oxidation half-wave potential E of compounds 5RR-1, ~5RR-9, (Ox) is Measurement was performed using a cyclic portammetry method using a saturated calomel electrode in a buffer solution with pH=13.0 (25° C.). The sample concentration during measurement was 10-3 to 1
It was 0-4 mol/λ.

These compounds may be used alone or in combination. In addition, when Mortar] is used as a dissolving agent or a dissolved physical development accelerator-releasing compound, among the developing agents used in the development of ordinary photographic materials, [,1
Any substance may be used as long as it forms an oxidant capable of cross-oxidizing the redox core A, but a preferred example is 1-phenyl-3, which is usually used as a cross-oxidizing agent in color diffusion transfer photosensitive materials. -There are pyrazolidinone derivatives. The developing agent may be contained in the processing solution or in the photosensitive material.

The physical development nucleus (4) in the present invention has the function of catalytically promoting the reaction in which metal ions or metal complex ions produced by dissolving the metal salt particles (2) are reduced to metal by a reducing agent. Indicates a substance that has As examples, metal sulfide colloids, noble metal colloids, etc. are used, and more specifically, palladium sulfide, nickel sulfide, silver sulfide, metal silver colloids, metal palladium colloids, etc. are preferably used.

The photographic light-sensitive element according to the present invention is basically produced by at least one support and the above-mentioned (1) photosensitive silver halide (2) substantially non-photosensitive metal salt particles (3) development. A compound (4) physical development nucleus and 1) H= which reacts with the oxidized developing agent to release a compound which acts as a solubilizer or a dissolving physical development accelerator for the metal salt particles mentioned in (2) above.
(1), (2), (
3), (4), and (A+) may each be contained in a single layer, or may have a structure including a layer containing two or more types in any combination. Various configurations can be taken for the order of (1),
(2), (3), (4) and fE) are separately contained on a plurality of supports in any combination and layer configuration,
A configuration may be used in which they are used together.

A particularly preferred layer structure of the silver halide photographic element according to the present invention is to coat a layer containing a mixture of (1), (2), (3) and (El) from the support side, and to apply (
Either layer 4) is applied to form a two-layer structure, or a layer consisting of a mixture of (1), (3) and (E) is applied from the support side, and then (2) is applied on top of that. A layer containing (2), (3) and It is preferable to apply a layer containing the champion of (E) and further apply a layer of (4) on top of that to form a three-layer structure.

Furthermore, depending on the purpose, the photographic element of the present invention may have appropriate layers at various positions as long as the effects of the present invention are not impaired, such as a protective layer, an intermediate layer, an antihalation layer, or a backing layer. It may also be in a so-called activated form, which includes a layer containing a developing agent.

Further, in the photographic element of the present invention, depending on the purpose, photographic additives other than those described above may be added to any layer of the photographic element to the extent that the effects of the present invention are not impaired. In order to particularly improve or improve printing properties such as water retention and printing durability, fine powder particles such as silica gel, colloidal silica, silicon dioxide, magnesium oxide, titanium dioxide, calcium carbonate, etc. may be used in any layer. can. Further, hardeners commonly used in the art can be used to strengthen adhesion to the support and physical properties of the film, and surfactants can also be used to improve the coating stability of the coating solution.

Next, any support can be used in the present invention as long as it has a hydrophilic surface.

For example, baryta paper, polyethylene-coated paper, cellulose acetate, polyester film such as polyethylene terephthalate, polyamide film, polystyrene film, glass plate, which has been subjected to corona discharge treatment, undercoating treatment, etc., or aluminum which has been anodized. Metal plates such as plates are included, but particularly preferred are polyethylene-covered paper, polyester films, and aluminum plates. Further, as the surface hydrophilic treatment methods such as the corona discharge treatment, undercoating treatment, and anodizing treatment, known methods commonly used in the art can be used.

The present invention will be explained in more detail below using typical examples, but the technical scope of the present invention is not limited thereby.

Example 1 (,) Preparation of high-sensitivity silver iodobromide emulsion (preparation of r(1) photosensitive silver halide grains) Iodide odor is removed from silver nitrate, potassium bromide, and potassium iodide by an ordinary neutral method. A silveride emulsion (silver iodide 2 mol %) was prepared, chemically sensitized by gold and sulfur sensitization, and 4-hydroxy-6-methyl-1,3,3ζ,7-titrazaindene was added as a stabilizer. A silver iodobromide emulsion with a grain size of 0.4 microns was obtained.

(b) Preparation method of desensitized iodosilver chloride emulsion (preparation of r (2+ non-photosensitive metal salt grains)) Desensitized iodosilver chloride emulsion using rhodium chloride as a desensitizer in silver nitrate, sodium chloride, and potassium iodide. (silver iodide 0.8 mol%) was prepared.

The grain size of the resulting emulsion grains was 0.1 micron.

tc+ Preparation of Physical Development Nuclei Physical development nuclei consisting of silver sulfide were prepared with sodium sulfide and silver nitrate in an aqueous polyvinyl alcohol solution.

(a) High-sensitivity silver iodobromide emulsion (
b) Desensitized silver iodochloride emulsion (el physical development nucleus (a) separately synthesized silver halide solvent-releasing redox compound 5RR-
By applying the following on a paper support using a gel containing 6 in gelatin by an oil dispersion method, and a gel in which a compound of 5 (, 1 electron donating compound) was incorporated in gelatin by an oil dispersion method. A sample of the present invention and a comparative sample shown in are prepared.

Sample 1-1 (Sample of the present invention) A layer containing (a), (d) and (,1) was coated, and (
Sample 1-2 where a layer containing bl was applied, and then a layer containing (c) was applied on top of that. (Comparative sample) A layer containing fal and (d) was applied, and then a layer containing (b) was applied. Sample 1-3 (comparative sample) on which a layer containing (cl) was applied (comparative sample) A layer containing (Tb) was applied on top of a layer containing (, ) and (,) on which a layer containing (Tb) was applied. Sample 1-4 coated with a layer containing c) Sample 1-4 (comparative sample) A layer containing f,) was coated, a layer containing (b) was coated, and a layer containing (c) was further coated on top of that. However, for all samples, the coated silver amount was 0.13 y/m' for the silver emulsion (,), and the coated silver amount was 0.13 y/m' for the desensitized silver iodochloride (b). 42P/Go, (cl
For palladium sulfide, the coating weight is 6 x 10-'
For the SRR compound (SRR-6) in (d), the coating amount is 0.4 mmol/g, and for the electron donating compound (compound 5.) in (,), the coating amount is 0.32 mmol/g. '
Coating was carried out so that J mole/g.

-25-〇The above samples were wedge exposed with 4.5ζMS light and then developed with a developer having the following composition at 20°C for 30 seconds.

After development, the sample was fixed using a commercially available Kodak F-5 fixer (manufactured by Eastman Kodak, USA), washed with water, and dried. The silver content of the sample was measured, and the results shown in Table 1 were obtained. Ta.

Table 1 In addition, mirror-like precipitated silver was observed in the exposed areas of Samples 1-1 and 1-2, while in Samples 1-3 and 1-4.
No deposited silver was observed in the exposed areas. On the other hand, no surface precipitated silver was observed in the non-exposed area of sample 1-1, whereas a slight amount of precipitated silver due to fog was observed in the non-exposed area of sample 1-2.

As is clear from the above results, it can be seen that only by the method of the present invention can a negative specular silver image with almost no fog in the unexposed areas and with good silver transfer efficiency in the exposed areas be obtained. It can also be understood that (e) does not work alone, but only shows its effect when coexisting with (d).

Next, sample 1-1 of the present invention and comparative sample 1- obtained here
Regarding 2, the surface is sensitized by wiping it with SLM-OH liquid (oil sensitizing liquid, manufactured by Mitsubishi Paper Mills Co., Ltd.), and then soaked in a water bath for 3 minutes to soak the surface with water.Then, the surface is printed using normal offset printing. When using a rubber roller coated with printing ink, sample 1-1-c was coated with ink only on the exposed area where the specular silver image was formed, whereas sample 1-2 was coated with ink not only on the exposed area but also on the exposed area. A small amount of ink also adhered to the non-exposed areas.

When paper was applied to these and an ink image was transferred onto the paper by pressing with a rubber roller, sample 1-1 yielded a clean image with no ink stains in the non-exposed areas, while sample 1-2 did not. Considerable ink stains were observed in the unexposed areas of the image.

From the above two points, it can be understood that a novel negative planographic printing plate free from fog can be obtained by the method of the present invention.

Example 2 High-sensitivity silver iodobromide emulsion (,) same as used in Example 1,
Gelatin gel with fdl's 5RR-6 dispersed in oil,
The coating amount of 5RR-6 is 0.6 and the coating amount of (,) is 03y/g, fd).
Mi! Jmol/go, and tel reducing agent5. was coated on a paper support so that the coating amount of Example 1. The same desensitized iodosilver chloride emulsion (b) used in (b) and (fl Thyroid 5Y-30
8 (silica gel powder, manufactured by Fuji Davison Co., Ltd.) was mixed with emulsion (b) with a coating amount of 0.7b and (fl
Apply so that the coating g is 1.0 f/rrl.

Furthermore, the same physical development nuclei (C) as used in Example 1 were coated thereon in an amount of 3 x 10-5 mol/Trt of palladium sulfide.

Sample 2 of the present invention having a three-layer structure prepared as described above was exposed, developed, and fixed in the same manner as in Example 1, and then the surface was oil-sensitized to prepare a printing plate.

When the printing plate thus obtained was run on an offset printing machine using normal offset printing ink and normal water as a wetting liquid, a clear ink image with no ink stains in the non-exposed areas was obtained. At the same time, it had a printing life of more than 500 copies.

From the above, it can be understood that the present invention is an excellent method for producing a negative planographic printing plate.

Example 3 The same high-sensitivity silver iodobromide emulsion (a) as used in Example 1, (bl-29) was deposited on a polyethylene terephthalate film.
−^ Town desensitized iodosilver chloride emulsion, physical development nuclei of (C) and (f)
Example 2. Sample prepared with 1
ii1-Prepare samples with the same configuration and the same coating amount. However, d
) as the SRR compound, 5R instead of 5RR-6
Using R-8 (coating amount: 0.6 mmol/go) and (e
) in sample 3-1, compound 2
．． In sample 3-2, compound 4. Moreover, in sample 3-3, compound 5. was used. These samples 3-1 to 3-3 were developed with the same developer used in Example 1 at 20° C. for 60 seconds, and then fixed in the same manner as in Example 1 to oil-sensitize the surfaces and prepare printing plates.

When the printing plate thus obtained was applied to an offset printing machine in the same manner as in Example 2, a clear image without ink stains was obtained, and the printing plate had a printing life of more than 500 copies. From the above, it can be understood that the present invention is an excellent method for producing a negative planographic printing plate.

Claims (1)

[Claims] On the support, (1) photosensitive silver halide, (2) metal salt particles having substantially no photosensitivity, and (3) the metal of (2) above reacts with the oxidized developing agent produced by development. A photosensitive photographic element containing a combination of a compound that releases a compound that acts as a salt particle solubilizer or a dissolved physical development accelerator, and (4) physical development nuclei is imagewise exposed and then developed to improve the In the method for producing a negative lithographic plate comprising the step of selectively precipitating the metal salt particles as a metal on the physical development nuclei of (4), a buffer having a pH of 13.0 is added to the photosensitive photographic element. A method for producing a negative planographic printing plate, comprising an electron donating compound (E) having a lower oxidation potential than the compound (3) at (25° C.).