JP2955244B2 - Method for producing lithographic printing plate by silver type diffusion transfer method by phototypesetting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to a method for obtaining a lithographic printing plate using a silver halide photographic material which is sensitive to high-brightness and short-time exposure by a silver salt diffusion transfer method.

BACKGROUND OF THE INVENTION With the recent rapid development of information transmission systems, silver halide photographic light-sensitive materials are increasingly required to have high sensitivity. Such systems include, for example, high-speed phototypesetting systems, in which information output from an electronic computer is immediately provided as text and graphics by a cathode ray tube and a press facsimile system for rapid transmission of newspaper manuscripts to remote locations. Is displayed.

[0003] Photo-typesetting machines on the market to date are usually He.
/ Ne laser (632 nm), laser diode (680 nm), or LED (670 nm or 780 n)
m).

For photographic materials which should be suitable for use for photocomposition, the material must have a so-called high brightness-short time exposure (flash or scanning exposure), ie a high exposure of less than 10 ^-4 seconds. It must be of high speed and produce images of high contrast and high resolution.

[0005] Photo-typesetting materials are, for example, US-P4501
811 and lithographic printing plates based on silver salt diffusion transfer (hereinafter referred to as DTR) and photographic films and papers used in the method of manufacturing lithographic printing plates described in U.S. Pat. No. 4,784,933. Using the former material, the lithographic printing plate
Obtained immediately without the need for contact or camera exposure.

[0006] The photographic DTR material preferably contains a sufficiently high proportion of a solution of silver halide and a silver halide emulsion consisting mainly of silver chloride to obtain the satisfactory gradation required for graphic purposes. Usually only a small amount of silver bromide and / or silver iodide not exceeding 5 mol% is present.

To obtain a printing plate, the sensitivity of the imaging material should be high. Higher sensitivity results in easier conversion of laser intensity. The sensitivity of an imaging material is affected by many factors, but to a significant extent by organic compounds, especially organic stabilizing compounds, contained in the photosensitive layer of said imaging material. Most current imaging materials contain 1-phenyl-5-mercapto-tetrazole as an organic stabilizing compound. However, the material could be used with high sensitivity.

SUMMARY OF THE INVENTION An object of the present invention is to improve the sensitivity of a silver halide photographic material which is sensitive to high-brightness and short-time exposure by a DTR method and obtain a lithographic printing plate having good printing characteristics. The purpose is to provide a method.

[0009] Further objects of the present invention will become clear from the description hereinafter.

According to the present invention, the following steps: (1) a photosensitive layer containing at least one photosensitive silver halide emulsion and a heterocyclic compound containing at least one nitrogen atom in a ring; An image-receiving layer containing a physical development nucleus in a water-permeable relationship with the photosensitive layer, by imagewise exposing the image-forming material contained on the support to high-brightness-short-time exposure; To provide a method for making a lithographic printing plate by a silver salt diffusion transfer method comprising a step of developing with an alkaline processing solution in the presence of a developing agent and a silver halide solvent, wherein the photosensitive layer is sulfonated. Naphthalene-O
Containing xazolidine-2-thione, and wherein the heterocyclic compound has at least one mercapto or thione group, and a linear or branched alkyl, alkenyl,
It is characterized by containing one substituent containing at least 5 carbon atoms selected from the group consisting of alkynyl, aralkyl and alkylaryl.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, when the image-forming material contains a compound as described above, a lithographic printing plate having good printing characteristics is obtained by the DTR method, and high-luminance-short-time exposure is achieved. And high sensitivity.

According to the present invention, the photosensitive layer contains the compound in an amount of from 0.0001 to 1 mol per mol of silver halide.
It is preferably contained in an amount in the range of 0.01 mol, and 0.0005 to 0.002 per mol of silver halide.
More preferably, it is contained in an amount in the range of mol.

According to the invention, said compound is selected from the group consisting of 2-mercapto-5-alkyl-1,3,4-thiadiazole and 2-mercapto-5-alkyl-1,3,4-oxadiazole. Preferred compounds are those wherein the 5-alkyl substituent contains at least 5 carbon atoms.

More preferably, said compound corresponds to the formula:

[0015]

Embedded image

Wherein R ⁴ represents an alkyl group containing 5 to 17 C atoms, more preferably R ⁴ represents an alkyl group containing 5 to 11 C atoms, and most preferably R ⁴ represents an alkyl group containing 5 to 11 C atoms.
⁴ represents an alkyl group containing 7 C atoms.

According to a preferred embodiment of the present invention, the imaging element in the context of the present invention for producing a lithographic printing plate comprises a photosensitive material containing a silver halide emulsion on a support in the following order: Layer and an image-receiving layer containing physical development nuclei in a water-permeable relationship with the emulsion layer.

Layers in water-permeable contact with each other are layers that are adjacent to one another or that are only separated from one another by a water-permeable layer. The nature of the water-permeable layer is such that it does not substantially inhibit or inhibit the diffusion of water or compounds contained in the aqueous solution, such as developing agents or complexed silver ions.

Supports suitable for use in accordance with the present invention can be opaque or transparent, for example, a paper support or a resin support. When a paper support is used, preference is given to one or both sides coated with an α-olefin polymer, for example a polyethylene layer containing, if desired, an antihalation dye or pigment. An organic resin support such as a cellulose nitrate film, a cellulose acetate film, a poly (vinyl acetal) film, a polystyrene film, a poly (ethylene terephthalate) film, a polycarbonate film, a polyvinyl chloride film, or a poly-α-olefin film such as polyethylene Alternatively, a polypropylene film can be used. The thickness of the organic resin film is 0.07 to 0.35 mm
It preferably comprises These organic resin supports are preferably coated with a hydrophilic adhesive layer that can contain water-insoluble particles such as silica or titanium dioxide. According to the invention, a metal support such as aluminum can also be used.

Photographic silver halide emulsions are described, for example, in Parry's Paul Montel, 1967, by P. Glafkides,
Chimie et Physique Photographique; Th in London
e Focal Press 1966, GF Duffin,
Photographic Emulsion Chemistry; and London
The Focal Press 1966, VL Zelikm
an et al., Making and Coating Photographic Emulsi
It can be prepared from soluble silver salts and soluble halides by various methods as described in on.

According to the invention, it is preferred that the emulsion consists mainly or entirely of silver chloride. However, 0.1-
A silver bromide fraction may be present in the range of 40 mol%.
When the silver bromide fraction is present at 5% or more, the emulsion belongs to the core / shell form well known to those skilled in the art in that substantially all of the silver bromide is concentrated in the core. preferable. This core contains 10-40 of the total silver halide precipitated.
%, While the shell preferably comprises 60-90% of the total silver halide precipitated.

The average grain size of the silver halide is 0.10 to 0.10.
0.70 μm range, preferably 0.25 to 0.45 μm
m.

Preferably during the precipitation stage iridium and / or
Or a rhodium-containing compound or a mixture of both is added. The concentration of these added compounds is 1 for 1 mol of AgNO _3.
The range is from 0 ^-8 to 10 ^-3 mol, preferably 0.5 × 10 ^-7 and 10 ^-5 for 1 mol of AgNO ₃ .

The emulsions can be chemically sensitized, for example, by adding sulfur containing compounds such as allyl isothiocyanate, allyl thiourea, and sodium thiosulfate during the chemical ripening stage. A reducing agent such as BE-P4
The tin compounds described in 93464 and BE-P568687, and polyamines such as diethylenetriamine or derivatives of aminoethanesulfonic acid can be used as chemical sensitizers. Other suitable chemical sensitizers include noble metals and noble metal compounds such as gold, platinum, palladium, iridium, ruthenium and rhodium. This chemical sensitization method is based on Z.
Wiss. Photogr. Photophys. Photochem.
951) 65-72 in R. KOSLOWSKY's dissertation.

Emulsions of DTR materials can be spectrally sensitized for exposure to laser light, eg, helium-neon laser light, and semiconductor laser light. Dyes that can be used to adjust the light sensitivity to laser light include, for example, J
A-Pi62-284344, 62-284345, 6
2-141561, 62-103649, 62-139
555,62-105147,62-105148,6
2-075638, 62-062353, 62-062
354,62-062355,62-157027,6
2-157028, 62-113148, 61-203
446,62-003250,60-061752,5
5-070834,51-115821,51-115
822, 51-106422, 51-106423, 5
1-106425; DE-A-3826700; US-
P-4501811, 4725532, 478493
3: US Serial No. 07/986071; GB-P
-1467638; EP-A 100654 and the references cited therein.

When exposing with a red light emitting source such as an LED or HeNe laser, for example, EP-A5454
A red sensitizing dye as described in 52 is used. In the case of exposure with a semiconductor laser, a special spectral sensitizing dye suitable for the near-infrared is disclosed, for example, in EP-A54
Required as described in US Pat. To enhance the sensitivity in the red or near infrared band, so-called supersensitizers can be used in combination with a red or infrared sensitizing dye. A suitable supersensitizer is Research Disclosure Vol.
89, May 1988, item 28952. Preferred red, infrared and supersensitizers are described in EP-A 554585.

The spectral sensitizer can be added to the photographic emulsion in the form of an aqueous solution, a solution in an organic solvent, or a dispersion.

The silver halide emulsion can contain other suitable stabilizers. Preferably, the photosensitive layer is azaindene,
Preferably tetra- or penta-azaindene, more preferably tetra- or penta-azaindene substituted with a hydroxy or amino group, more preferably 4
-Hydroxy-6-methyl-1,3,3a, 7-tetraazaindene may also be included. The photosensitive layer preferably contains the azaindene in an amount in the range of 20-2000 mg / mol silver halide, more preferably in the range of 100-500 mg / mol silver halide.

The photosensitive layer also preferably contains a sulfonated naphthalene-oxazolidine-2-thione, more preferably 7-sulfo-naphtho- (2,3-d) -oxazolidine-2-thione. The photosensitive layer preferably contains the sulfonated naphthalene-oxazolidine-2-thione in an amount of from 60 to 6000 per mol of silver halide.
mg, more preferably 1 mol silver halide.
It is contained in an amount in the range of 200 to 1200 mg for 1. The sulfonated naphthalene-oxazolidine-2-
Thione is preferably azaindene, more preferably 4-
It is used in the form of a mixture with hydroxy-6-methyl-1,3,3a, 7-tetraazaindene.

The silver halide emulsion can contain a pH controlling component. Preferably, the emulsion layer is coated at a pH value near the isoelectric point of the gelatin to improve the stability properties of the coating layer. Other ingredients such as antifoggants, development accelerators, wetting agents and hardening agents for gelatin may be present. The silver halide emulsion layers can contain light screening dyes that absorb scattered light and thus promote image sharpness. Suitable light-absorbing dyes are, for example, US-P 4,092,168, US-P 431.
1787 and DE-P2453217.

Further details on the composition, preparation and coating of silver halide emulsions can be found, for example, in Product Licensing Index.
x, Vol. 92, December 1971, Publication 92
32 pages 107-109.

The layer containing the physical development nuclei may not contain a hydrophilic binder, but in order to improve the degree of surface hydrophilicity, a hydrophilic colloid, for example polyvinyl alcohol, is added, for example, to the total weight of said layer. It preferably contains up to 80% by weight. Preferred development nuclei for use according to the invention are sulfides of heavy metals, such as antimony,
Bismuth, cadmium, cobalt, lead, nickel, palladium, platinum, silver and zinc sulfides. Particularly preferred development nuclei in the context of the present invention are palladium sulfide nuclei. Other suitable development nuclei include heavy metal salts such as selenides, polyselenides, polysulfides, mercaptans and tin (II) halides. Heavy metals, preferably silver, gold, platinum, palladium and mercury, can be used in colloidal form.

Between the support and the silver halide emulsion layer is preferably provided a base layer containing an antihalation substance such as a light absorbing dye which absorbs light, for example for imagewise exposure of the imaging element. Is preferred. Alternatively, micronized carbon black can be used as the antihalation substance. On the other hand, in order to obtain an increase in sensitivity, a light reflecting pigment,
For example, titanium dioxide can be present in the substrate. In addition, this layer is a hardener, matting agent, for example silica particles,
And a humectant. Suitable matting agents are preferably 2
It has an average diameter of from 10 to 10 μm, more preferably from 2 to 5 μm. Matting agents are generally 0.1-2.5 g in the imaging element
/ M ² . At least a part of these matting agents and / or light-reflecting pigments may contain a halogenated emulsion layer and / or
Alternatively, it can be present in the cover layer. As a further alternative, the light reflecting pigment may be present in a separate layer between the antihalation layer and the photosensitive silver halide emulsion layer. At the same time as the emulsion layer, the base layer is preferably coated at a pH value near the isoelectric point of the gelatin in the base layer.

In a preferred embodiment in the context of the present invention, a backing layer is provided on the non-photosensitive side of the support. This layer, which can act as an anti-curl layer, can contain, for example, matting agents such as silica particles, lubricants, antistatic agents, light absorbing dyes, opacifiers such as titanium dioxide and customary components such as hardeners and wetting agents. The backing layer can consist of a single layer or a double layer pack.

The hydrophilic layer usually contains gelatin as a hydrophilic colloid binder. To adjust the flow properties of the bed,
Mixtures of different gelatins with different particle sizes can be used. Like the emulsion layer, the other hydrophilic layer is preferably coated at a pH value near the isoelectric point of gelatin. However, instead of or together with gelatin, one or more other natural and / or synthetic hydrophilic colloids such as albumin, casein, zein, polyvinyl alcohol, alginic acid or its salts, cellulose derivatives such as carboxymethylcellulose, modified gelatins such as phthalo Il gelatin or the like can be used.

The hydrophilic layer of the photographic material may comprise a suitable hardening agent, for example of the vinylsulfone type, for example methylenebis (sulfonylethylene), an aldehyde such as formaldehyde, glyoxal, and glutaraldehyde, especially when the binder used is gelatin. It can be cured with N-methylol compounds such as dimethylol urea and methylol dimethylhydantoin, active halogen compounds such as 2,4-dichloro-6-hydroxy-s-triazine, and mucohalic acids such as mucochloric acid and mucophenoxycyclolic acid. These curing agents can be used alone or in combination. The binder may also be a rapid reaction hardener such as US-P4
Curing with carbamoylpyridinium salts of the type described in US Pat.

The curing agents preferably used are of the aldehyde type. The curing agent can be used in a wide concentration range,
Preferably it is used in an amount of 4 to 7% of the hydrophilic colloid. Different amounts of curing agent can be used in different layers of the imaging material, or the curing of one layer can be adjusted by diffusion of the curing agent from another layer.

The imaging elements used according to embodiments of the present invention may further contain various surfactants in the photographic emulsion layer or in at least one other hydrophilic colloid layer. Examples of suitable surfactants are described, for example, in EP 545452. Preferably, a compound containing a perfluorinated alkyl group is used.

The photographic material of the embodiment of the present invention may contain various other additives such as a compound for improving the dimensional stability of the photographic material,
It may further contain UV absorbers, spacing agents and plasticizers.

Additives suitable for improving the dimensional stability of the photographic material include, for example, dispersions of water-soluble or almost insoluble synthetic polymers, for example alkyl (meth) acrylates,
Alkoxy (meth) acrylate, glycidyl (meth)
Acrylates, (meth) acrylamides, vinyl esters, acrylonitrile, polymers of olefins and styrene, or acrylic and methacrylic acids with those described above,
There are dispersions of copolymers of α, β-unsaturated carboxylic acids, hydroxyalkyl (meth) acrylates, sulfoalkyl (meth) acrylates, and styrene sulfonic acids.

[0041] The DTR monosheet imaging element described above in connection with the present invention comprises an apparatus according to its particular use,
Exposure is for example in an LED or laser containing device. The imaged material is subsequently developed with an alkaline processing liquid in the presence of a developing agent and a silver halide solvent.

The alkaline processing liquid used for developing the image-forming material according to the method of the present invention preferably contains a silver halide solvent. Preferably the silver halide solvent is in an amount of 0.01 to 10% by weight, more preferably 0.1 to 10% by weight.
It is used in an amount of from 0.5 to 8% by weight. Silver halide solvents suitable for use in connection with the present invention include, for example, 2
-Mercaptobenzoic acid, cyclic imides, oxazolidones and thiosulfates. Silver halide solvents that are preferably used in connection with the present invention include thiocyanates and alkanolamines.

Alkanolamines suitable for use in connection with the present invention can be of the tertiary, secondary or primary amine type. Examples of alkanolamines that can be used in connection with the present invention correspond to the formula:

[0044]

Embedded image

In the formula, X and X ′ are each independently hydrogen,
Represents a hydroxyl group or an amino group, l and m represent 0 or an integer of 1 or more, and n represents an integer of 1 or more. Alkanolamines preferably used include, for example, N- (2
-Aminoethyl) ethanolamine, diethanolamine, N-methylethanolamine, triethanolamine, N-ethyldiethanolamine, diisopropanolamine, ethanolamine, 4-aminobutanol,
There are N, N-dimethylethanolamine, 3-aminopropanol, N, N-ethyl-2,2'-iminodiethanol, 2-aminoethyl-aminoethanol and the like or a mixture thereof.

According to the invention, the alkanolamine is
Preferably, it is present in the alkaline processing liquid. However, some or all of the alkanolamine can be present in one or more layers of the imaging element.

A further preferred type of silver halide solvent is a thioether compound. The thioethers preferably used correspond to the general formula:

Z- (R ¹ -S) _t -R ² -SR ³ -Y

In the formula, Z and Y each independently represent hydrogen, an alkyl group, an amino group, an ammonium group, a hydroxyl group, a sulfo group, a carboxyl group, an aminocarbonyl group or an aminosulfonyl group, and R ¹ , R ² and R ³ each independently represents an alkylene group which may be substituted and optionally contains an oxygen bridge;
Represents an integer of 0. Examples of thioether compounds corresponding to the above formula are, for example, US-P 4,960,683 and EP-A5
47662, which are therefore incorporated herein by reference.

Still further suitable silver halide solvents include isoionic compounds. Preferred mesoionic compounds for use in connection with the present invention include triazolium thiolate and more preferably 1,2,4-triazolium-3-thiolate.

Preferably at least part, and more preferably all, of the mesoionic compound is present in the alkaline processing liquid used to develop the image-wise exposed imaging element. The amount of the mesoionic compound in the alkaline treatment liquid is preferably from 0.1 mmol / l to 25 mmol / l, more preferably from 0.5 mmol / l to 15 mmol / l, most preferably from 1 mmol / l to 8 mmol / l.

However, the isoionic compound can be incorporated into one or more layers included on the support of the imaging element. In this case, the mesoionic compound is preferably contained in the image forming material in a total amount of 0.1 to 10 mmol / m ² , more preferably 0.1 to 5 mmol / m ² , and most preferably 0.5 to 1 mmol / m ^2. 0.5 mmol / m ²
To be contained. Further details are described in EP-A 0 545 585.

The alkaline processing liquid used according to the present invention preferably has a pH of 9 to 14,
It is more preferred to have The pH can be established with an organic or inorganic alkaline substance or a combination thereof. Suitable inorganic alkaline substances include, for example, potassium or sodium hydroxide, carbonate, phosphate and the like. Suitable organic alkaline substances include, for example, alkanolamines. In the latter case, the alkanolamine helps provide or maintain the pH and acts as a silver halide complexing agent.

The alkaline processing liquid may also contain a developing agent. In this case, the alkaline processing liquid is called a developer.
Alternatively, some or all of the developing agent can be present in one or more layers of the photographic or imaging material. When all of the developing agent is contained in the imaging element, the alkaline processing liquid is called an activator or activating liquid.

The silver halide developing agent for use according to the present invention is preferably a p-dihydroxybenzene-based developing agent such as hydroquinone, methylhydroquinone or chlorohydroquinone, and is preferably a 1-phenyl-3-pyrazolidone-based developing agent and / or p-dihydroxybenzene-based developing agent. Preferably in combination with an auxiliary developing agent which is monomethylamine phenol. A particularly useful auxiliary developing agent is 1-phenyl-3-pyrazolidone. Especially when they are mixed in photographic materials,
Even more preferred is 1-phenyl-3-pyrazolidone with increased aqueous solubility with hydrophilic substituents such as hydroxy, amino, carboxylic acid groups, sulfonic acid groups and the like. Examples of 1-phenyl-3-pyrazolidone substituted with one or more hydrophilic groups include, for example, 1-phenyl-4,4-dimethyl-2-hydroxy-3-pyrazolidone, 1- (4-carboxyphenyl)- 4,4-dimethyl-3-pyrazolidone and the like. However, other developing agents can be used.

At least the auxiliary developing agent is incorporated in the photographic material, preferably in the silver halide emulsion layer of the photographic material.
150m silver halide 1g, expressed as NO ₃
Preferably, it is incorporated in an amount of less than 100 g, more preferably less than 100 mg / g of silver halide expressed as AgNO ₃ .

According to the present invention, the alkaline processing liquid used for developing the image-forming material as described above also contains a hydrophobizing agent to improve the hydrophobicity of the silver image obtained in the image-receiving layer. Is preferred. Hydrophobizing agents used in the context of the present invention are compounds which are capable of reacting with silver or silver ions and are hydrophobic, i.e. insoluble or only slightly soluble in water. Generally, these compounds contain a mercapto or thiolate group and one or more hydrophobic substituents, for example, an alkyl group containing at least 3 carbon atoms. Examples of hydrophobizing agents for use according to the invention include, for example, those described in US Pat. No. 3,776,728 and US Pat. No. 4,563,410. Preferred compounds correspond to one of the following formulas:

[0058]

Embedded image

[0059]

Embedded image

[0060] wherein R ⁵ represents hydrogen or an acyl group, R ⁴
Represents an alkyl group, an aryl group or an aralkyl group. Most preferably used compounds are those wherein R ⁴ is 3-16 C
A compound according to one of the above formulas representing an alkyl group containing an atom.

According to the invention, the hydrophobizing agent is present in the alkaline processing liquid in an amount of at least 0.1 g / l, more preferably at least 0.2 g / l, and most preferably at least 0.3 g / l. It is contained in. The maximum amount of the hydrophobizing agent is determined by the type of the hydrophobizing agent, the type and amount of the silver halide solvent, and the like. Typically, the concentration of the hydrophobizing agent is preferably 1.5 g / l or less, more preferably 1 g / l or less.

The alkaline processing liquid preferably also contains a preservative having antioxidant activity, for example, sulphite ions, for example sulphite ions provided by sodium or potassium sulphite. For example, the aqueous alkaline solution contains sodium sulfite in an amount of 0.15 to 1.0 mol / l. Further thickeners such as hydroxyethylcellulose and carboxymethylcellulose, antifoggants such as potassium bromide, potassium iodide and benzotriazoles which are known to improve print durability, calcium ion sequestering compounds, sludge inhibitors and latent curing Curing agents, including agents, can be present. According to the invention, it is further preferred to use a spreading agent or a surfactant in the alkaline processing liquid in order to ensure an even spreading of the alkaline processing liquid on the surface of the photographic material. Such surfactants should be stable at the pH of the alkaline processing liquid and ensure rapid overall wetting of the surface of the photographic material. Suitable surfactants for this purpose for example, a fluorine-containing surfactant for example C ₇ F ₁₅ COONH _4.
It is further advantageous to add glycerin to the alkaline processing liquid so as to prevent crystallization of the dissolved components of the alkaline processing liquid.

The development is accelerated by adding various compounds, preferably, for example, US Pat. No. 3,038,805, US Pat. No. 4,403,807 to one or more layers of the alkaline processing solution and / or the photographic material.
5, US-P4292400, US-P4975354
This can be accomplished by adding a polyalkylene derivative having a molecular weight of at least 400, such as those described in US Pat.

Following development in an alkaline processing liquid according to the invention, the surface of the printing plate is preferably neutralized with a neutralizing liquid.

The neutralizing solution generally has a pH of 5-8. It preferably contains a neutralizing solution, a buffer such as a phosphate buffer, a citrate buffer or a mixture thereof. The neutralizing solution may further comprise a bactericide, a substance which affects the hydrophobic / hydrophilic balance of the printing plate obtained after processing of the DTR material, such as hydrophobizing agents as described above, silica and wetting agents, preferably perfluorinated alkyls. Compounds containing groups can be included.

Thus, a lithographic printing plate is obtained.

According to another embodiment of the present invention, lithographic printing is carried out by the DTR method using an imaging material containing a layer of physical development nuclei and a silver halide emulsion layer on the hydrophilic surface of the support in the following order: You can get a version.

The hydrophilic surface of the support can be a cured hydrophilic layer containing a hydrophilic binder and a curing agent coated on a flexible support.

Such a hydrophilic binder is, for example, EP-A45
0199, which is hereby incorporated herein by reference. Preferred cured hydrophilic layers are, for example, E
Contains pullulan or partially modified dextran cured with aldehydes as described in P-A514990. For this reason, it is incorporated herein by reference. More preferred hydrophilic layers are preferably SiO ₂ and / or TiO ₂
And cured with a tetraalkyl orthosilicate, wherein the weight ratio between the polyvinyl alcohol and the tetraalkyl orthosilicate is, for example, GB-P141951.
2, FR-P2300354, US-P396166
0.5, as described in US-P 4,284,705, EP-A 405 016 and EP-A 450 199.
5, which are therefore incorporated herein by reference.

A flexible support, such as a paper support or a resin support, has been described above.

The hydrophilic layer of the support can be a hydrophilic metal support such as an aluminum foil.

The aluminum support of the imaging element for use according to the present invention can be made of pure aluminum or an aluminum alloy having an aluminum content of at least 95%. The thickness of the support is usually about 0.5.
It ranges from 13 to about 0.50 mm.

The production of aluminum or aluminum alloy foil for lithographic offset printing involves the following steps: graining, anodizing, and optionally sealing the foil.

Graining and anodizing of the foil are necessary to obtain a lithographic printing plate which allows to produce high quality prints according to the present invention. Sealing is not required, but can further improve the printing results. Preferably, the aluminum foil has a roughness with a CLA value of 0.2 to 1.5 μm, 0.
It has an anodized layer with a thickness of 4 to 2.0 μm and is sealed with an aqueous bicarbonate solution.

According to the invention, the roughening of the aluminum foil can be carried out by methods well known to those skilled in the art. The surface of the aluminum substrate can be roughened by mechanical, chemical or electrochemical graining, or a combination thereof, to obtain satisfactory adhesion of the silver halide emulsion layer to the aluminum support, and to be printed. Good water retention can be provided to the area forming the non-printing area on the plate surface.

Electrochemical graining is preferred because it can form a uniform surface roughness having a large average surface area with very fine and uniform particles normally desired when used for lithographic printing plates. Because.

The electrochemical particle formation can be carried out in an electrolytic solution containing hydrochloric acid and / or nitric acid using alternating current or direct current. Other aqueous solutions which can be used in the electrochemical granulation include, for example, if desired, one or more additional corrosion inhibitors, for example Al (NO ₃ ) ₃ , AlCl ₃ , boric acid, chromic acid, sulfates, chlorides, nitrates , monoamines, diamines, aldehydes, phosphates, acid such as _{H 2 SO 4, H 3 PO} 4 containing H ₂ O ₂ or the like.

Electrochemical graining in the context of the present invention can be performed using single-phase and three-phase alternating current. The current applied to the aluminum plate is preferably from 10 to 35V.
The current density of 3-150 Amp / dm ^2, using 5-240 seconds. The temperature of the electrolyte particle forming solution can be varied between 5 and 50C. Electrochemical granulation is preferably 10 Hz
This is performed using an alternating current of 300 Hz.

The surface roughening is preferably performed prior to the degreasing treatment in order to mainly remove grease-like substances from the surface of the aluminum foil.

Accordingly, the aluminum foil can be subjected to a degreasing treatment with a surfactant and / or an aqueous alkaline liquid.

The surface roughening is preferably carried out by a chemical etching treatment using an aqueous solution containing an acid. Preferably, the chemical etching is performed at at least 30 ° C, more preferably at least 40 ° C, most preferably at least 50 ° C.

[0082] Acids suitable for use in the aqueous etching solution are preferably inorganic acids and most preferably strong acids. Preferably, the total amount of acid in the aqueous etching solution is at least 150 g / l. Preferably, the duration of the chemical etching is between 3 seconds and 5 minutes.

After roughening and optional chemical etching,
Aluminum foil undergoes anodic oxidation, which is preferably performed as follows.

The current is passed through a grained aluminum foil immersed as an anode in a solution containing sulfuric acid, phosphoric acid, oxalic acid, chromic acid or an organic acid such as fumaric acid, benzenesulfonic acid or the like, or a mixture thereof. Within the temperature range of 0-70 ° C., electrolyte concentrations of 1-70% by weight can be used. Anodizing current density can vary the voltage within a range of 1~50A / dm ² Then 1~100V, 1~8g / m ²
Al ₂ O ₃ .H ₂ O anodized film weight can be obtained. The anodized aluminum foil is subsequently
It is recommended to wash with deionized water within a temperature range of 80 ° C.

After the anodizing step, sealing can be applied to the anodized surface. Sealing the pores of the aluminum oxide layer formed by anodization is a technique known to those skilled in the art of aluminum anodization. This technology is for example Sealing-kwal
iteit en sealing-controle van geanodiseerd
Under the title of Aluminum, Belgisch-Nederlands tijdschri
ft voor Oppervlaktetechnieken van materialen,
24ste jaargang / januari 1980. There are various types of sealing of porous aluminum anodized surfaces.

Preferably, said seal comprises a grained, anodized aluminum support as described in EP-A56717.
8 by treatment with an aqueous solution containing bicarbonate (for which reason the above patents are incorporated herein by reference).

Preferably, each of the aforementioned steps is separated by a washing step to avoid contamination of the liquid used in the particular step with the liquid of the preceding step.

To promote image sharpness and, consequently, the sharpness of the final printed copy, the anodized layer may be entirely coated with an antihalation dye or pigment, for example as described in JA-Pu 58-14797. Should be colored.

As a binder in the silver halide emulsion layer in the context of the present invention, a hydrophilic colloid, usually a protein, preferably gelatin can be used. However, gelatin can be partially or completely replaced by synthetic, semi-synthetic or natural polymers. Preferably, the silver halide emulsion layer comprises at least one gelatin species having a viscosity of less than 20 mPas at a shear rate of 1000 / s of less than 20 mPas at 36 ° C. and a 10% by weight aqueous solution at pH 6 in combination with a high viscosity gelatin. It contains.
The weight cost of said low viscosity gelatin relative to high viscosity gelatin is preferably> 0.5.

Preferably, the gelatin layer is not substantially hardened. Substantially uncured means that such a gelatin layer was coated on a subbed polyethylene terephthalate film substrate at a dry thickness of 1.2 g / m ² ,
° C and 35% R.C. H. When dried in water at 30 ° C. for 3 days, the gelatin layer becomes 95% by weight within 5 minutes.
It means to dissolve more.

The imaging material of this embodiment can be imaged using scanning exposure as described above, followed by a development step in the presence of a developing agent and a silver halide solvent according to the present invention,
Thus, a silver image is formed in the physical development nucleus layer. The silver halide emulsion layer and other optional hydrophilic layers are subsequently removed, for example, by washing the imaged material with water, preferably at 30 ° C. to 50 ° C., thus exposing the silver image.

To facilitate the removal of the silver halide emulsion layer, a hydrophilic non-protein film forming polymer such as polyvinyl alcohol, a polymer bead such as poly () is provided between the hydrophilic surface of the support and the silver halide emulsion layer. (Meth) acrylate beads, mixtures thereof, particles of water-insoluble inorganic compounds having a number average particle size of at least 0.1 μm or at least 50
It is advantageous to provide a layer containing an alkali-insoluble non-polymeric organic compound having a melting point of ° C. and a number average particle size of 0.1 to 10 μm. Layers of this type are described in EP-A 4834.
15, EP-A410500, EP-A9420377
9.7 and EP-A 95201713.5.

Finally, the exposed and imaged surface of the hydrophilic support is treated with a finish to enhance the water receptivity of the non-image areas and render the image areas oleophilic ink receptive.

The lithographic composition, referred to as a finish, comprises at least one compound that enhances the lacquer and / or ink receptivity of the silver image and at least one compound that improves the ink repellency of the hydrophilic surface. It contains.

Ingredients suitable for the finish include, for example,
There are organic compounds containing a mercapto group, such as the above-mentioned hydrophobizing compounds, for the alkaline processing solution. The hydrophobizing agent is contained in the finishing agent preferably at a total concentration of 0.1 to 10 g / l, more preferably at a total concentration of 0.3 to 3 g / l.

Additives that improve the lipophilic ink repellency of the hydrophilic surface region include, for example, carbohydrates such as acidic polysaccharides such as arabic gum, carboxymethyl cellulose, sodium alginate, propylene glycol esters of alginic acid, hydroxyethyl starch, dextrin, hydroxy Ethyl cellulose, polyvinyl pyrrolidone, polystyrene sulfonic acid, polyvinyl alcohol,
And preferably, there is polyglycol which is a reaction product of ethylene oxide and / or propylene oxide with water or alcohol. Optionally hygroscopic substances such as sorbitol, glycerol, tri (hydroxyethyl) ester of glycerol, and sulfated oils (turkis
h red oil) can be added.

Thus, a lithographic printing plate is obtained.

The present invention will now be illustrated by the following examples.
However, the present invention is not limited to this. All parts are parts by weight unless otherwise specified.

Example 1 Preparation of silver halide emulsion coating solution

Gelatin silver halide emulsion I was 3 mol
Aqueous solution of AgNO ₃ with a concentration of
Aqueous solutions having a concentration of 1 / l and KBr of 0.054 mol / l were made using double jet precipitation by mixing with stirring. Prior to precipitation, 5 × 10 ⁻⁴ mol / l sodium hexachlororhodaat was added to the alkali halide solution.

The temperature during silver halide formation was 50 ° C. The resulting emulsion was cooled, aggregated and washed. Gelatin was added in an amount sufficient to reach a 2/3 (by weight) ratio of gelatin to silver halide, expressed as equivalents of silver nitrate.

Subsequently, the chemical ripening of Emulsion I was carried out in a conventional manner known to the person skilled in the art, by first adding 0.02 mol of KI per mol of AgNO ₃ and subsequently thiosulphate and gold salts. A silver chlorobromoiodide emulsion comprising 98.0 mol% of silver chloride, 1.8 mol% of silver bromide and 0.2 mol% of silver iodide and containing rhodium ions as an internal dopant was thus prepared. The average silver halide grain size was 0.4 μm (diameter of a sphere having the same volume). 4-hydroxy-6-methyl- as a stabilizer
1,3,3a, 7-Tetraazaindene was added in an amount of 290 mg per mol of silver halide.

Before coating, Emulsion I was red sensitized with a red sensitizing dye. Finally, 1-phenyl-5-mercaptotetrazole (9.5 × 1 per mol of silver halide)
0 ^-4 mol) and 7-sulfo-naphtho- (2,3-d)
-Oxazolidine-2-thione (1 mol of silver halide
Was added to the emulsion.

Emulsion II was prepared by mixing 1-phenyl-
Emulsion I was made in the same manner as Emulsion I, except that 5-mercaptotetrazole was replaced with an equimolar amount of 2-mercapto-5-n-heptyl-1,3,4-oxadiazole.

Emulsion III was prepared by combining 1-phenyl-5-mercaptotetrazole in Emulsion I with an equimolar amount of 1-
Emulsion I was made in the same manner as Emulsion I, substituting with (3-octanamidophenyl) -5-mercaptotetrazole.

An undercoating solution having the following composition was prepared: gelatin 5.5% carbon black 0.76% silica particles (5 μm) 1.6%

Production of image forming materials 1 to 3

Primed polyethylene terephthalate coated with two backing layer packs, each with emulsion coating solutions I-III coated on the side of the support opposite to the side containing the backing layer The support was simultaneously coated with the substrate coating solution by the cascade coating method. The emulsion layer is AgNO
Silver halide coverages, expressed as ₃ 1.25 g / m
² and a gelatin content of 1.33 g / m ² . The emulsion further contains 0.15 g / m ² of 1-
Hydroquinone phenyl-4,4'-dimethyl-3-pyrazolidone and 0.25 g / m ² was included. The base layer, the amount of gelatin in the coated layer was coated such that 3 g / m ^2.

The first subbing layer on the back side was 2.2 mg / m
² of polystyrene sulphonic acid and 0.9 mg / m ² poly - contained an antistatic composition 3.1 mg / m ² consisting of (3,4-ethylenedioxythiophene).

The layer of the backing pack closest to the support contained 0.08 g / m ² of gelatin. The second backing layer is a matting agent comprising gelatin 2.8 g / m ² , transparent spherical polymer beads having an average diameter of 3 μm according to EP-A080225.
065 g / m ² , dispersed barium sulfate (average diameter 0.
2. 3 to 0.4 mμ) 1.5 g / m ² , colloidal silica
0 g / m ² , curing agent triacryl formal 0.05 g
/ M ² and wetting agent F ₁₅ C ₇ -COONH ₄ 0.021 g / m ²
Was contained.

The material thus obtained is dried and
Exposure to a temperature of 0 ° C., then the emulsion layer is washed with PdS as physical development nuclei, hydroquinone at 0.4 g / m ² and 1
It was overcoated with a layer containing formaldehyde at 00 mg / m ² .

The following treatment solution was prepared: activator solution A sodium hydroxide 30 g sodium sulfite anhydride 35 g 1-methyl-4-allyl-5-methyl-1,2,4-triazolim-3-thiolate 1100 mg 2-amino Ethyl-aminoethanol 20 ml 2-mercapto-5-n-heptyl-oxa-3,4-diazole 350 mg Water was made up to 1 l.

Neutralization solution Citric acid 10 g Sodium citrate 35 g Sodium sulfite anhydride 5 g Phenol 50 mg Water was made up to 1 l.

The above-mentioned image forming materials 1 to 3 are image-wise exposed by an LED image setter, and are exposed to the above-mentioned activator solution at 30 ° C. for 2 hours.
Treated for 0 seconds, then neutralized at 25 ° C. with the neutralizing solution and dried.

The results are shown in the table below.

Sensitometric properties Sensitivity and toe gradients were evaluated as follows:

Sensitivity: negative logarithm of exposure at density = (Dmax + Dmin) / 2. The higher the number, the higher the sensitivity of the material.

Gradients: Dmin + 0.10 and Dmin +
Average gradient between 0.25.

[0119]

From the results shown in Table 1, 1- (3-
Imaging material containing (octanamidophenyl) -5-mercaptotetrazole (imaging material according to the invention)
Is clearly higher in sensitivity when exposed by high-brightness and short-time exposure than the imaging material 1 containing 1-phenyl-5-mercaptotetrazole (comparative imaging material). The gradient foot remains the same.

Further, from the results in Table 1, it can be seen that the image-forming material 2 containing 2-mercapto-5-n-heptyl-1,3,4-oxadiazole as a stabilizer (image-forming material according to the present invention) has 1 It is evident that the image-forming material 1 containing -phenyl-5-mercaptotetrazole (comparative image-forming material) has much higher sensitivity when exposed by high-brightness-short-time exposure. The gradient foot, which is the speed for the tendency to contaminate (the higher the value, the less the tendency to contaminate) is also better for the imaging material 2 than for the imaging material 1.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-323659 (JP, A) JP-A-57-48733 (JP, A) JP-A-6-59454 (JP, A) JP-A-5-59454 127387 (JP, A) EP 489983 (EP, A1) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03F 7/07, 7/00

Claims (9)

(57) [Claims] 1. The following steps: (1) a photosensitive layer containing at least one photosensitive silver halide emulsion and a heterocyclic compound containing at least one nitrogen atom in a ring; An image-receiving layer containing a physical development nucleus having a water-permeable relationship is image-wise exposed to high-brightness-short-time exposure of an image-forming material contained on a support, and (2) the image-forming material is developed with a developing agent And a method for producing a lithographic printing plate by a silver salt diffusion transfer method comprising a step of developing with an alkaline processing solution in the presence of a silver halide solvent, wherein the photosensitive layer comprises a sulfonated naphthalene-oxazolidin-2-thione. And the heterocyclic compound containing at least one nitrogen in the ring,
Containing at least one mercapto or thione group and one substituent containing at least 5 carbon atoms selected from the group consisting of linear or branched alkyl, alkenyl, alkynyl, aralkyl and alkylaryl. Characteristic manufacturing method. 2. The photosensitive layer contains the heterocyclic compound containing at least one nitrogen atom in a ring in an amount ranging from 0.0001 to 0.01 mol per mol of silver halide. The method of claim 1, wherein: 3. The method according to claim 1, wherein the heterocyclic compound containing at least one nitrogen atom in the ring is 2-mercapto-5-alkyl-1,3,4-thiadiazole and 2-mercapto-5-alkyl-1,2. 3. The method according to claim 1, wherein the method is selected from 3,4-oxadiazole, wherein the alkyl group contains at least 5 carbon atoms. 4. The heterocyclic compound containing at least one nitrogen atom in the ring is represented by the following formula: ^4. The process according to claim 1, wherein R ⁴ represents an alkyl group containing 5 to 17 C atoms. 5. The method according to claim 4, wherein R ⁴ represents an alkyl group containing 5 to 11 C atoms. 6. The method of claim 5, wherein R ⁴ represents an alkyl group containing 7 C atoms. 7. The method according to claim 1, wherein the image-forming material comprises at least one photosensitive silver halide emulsion containing a heterocyclic compound containing at least one nitrogen atom in a ring on a support in the following order. A method according to any of claims 1 to 6, characterized in that it comprises a photosensitive layer comprising: a photosensitive layer comprising: a photosensitive layer; and an image receiving layer comprising physical development nuclei in water permeable relationship with said photosensitive layer. 8. The method according to claim 1, wherein the photosensitive layer comprises 4-hydroxy-6.
8. The method of claim 7, comprising methyl-1,3,3a, 7-tetraazaindene. 9. The method according to claim 9, wherein the photosensitive layer is 4-hydroxy-6-.
9. The method according to claim 8, wherein methyl-1,3,3a, 7-tetraazaindene is contained in an amount ranging from 100 to 500 mg per mol of silver halide.