JP2883973B2 - Imaging materials for making improved printing plates by silver salt diffusion transfer method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an imaging element for making an improved lithographic printing plate by a silver salt diffusion transfer method. Further, the present invention relates to a method for producing an improved lithographic printing plate by a silver salt diffusion transfer method.

[0002]

2. Description of the Related Art The principle of silver complex salt diffusion transfer reversal method (hereinafter referred to as DTR method) is described in, for example, US Pat. No. 2,352,014 and The Focal Press 197 in London and New York.
Published 2 years, by Andre Rott and Edith Weyde, Photog
raphic Silver Halide Diffusion Processes.

In the DTR method, undeveloped silver halide of a photographic silver halide emulsion layer material exposed according to information is converted into a soluble silver complex compound with a so-called silver halide solvent, and this is diffused into an image receiving material. And reduced therein with a developing agent, generally in the presence of a physical development nucleus,
A silver image ("DTR image") is formed having an image density value that is the inverse of the black silver image obtained in the exposed areas of the photographic material.

[0004] The DTR image bearing material can be used as a lithographic printing plate, where the DTR silver image areas form water repellent ink receptive areas on a water receptive ink repellent background.

The DTR image can be formed in the image receiving layer of a sheet or web material (a so-called two-sheet DTR material) which is a separate material to the photographic silver halide emulsion material, or at least one photographic silver halide emulsion. Formation in an image-receiving layer of a so-called single support material (also referred to as a mono-sheet material) containing at least one photographic silver halide emulsion layer integral with an image-receiving layer in water-permeable relationship with the layer it can. The latter monosheet format is preferred for producing offset printing plates by the DTR method.

[0006] There are two types of monosheet DTR offset printing plate precursors. For example, US-P47225
According to No. 35 and the first type described in GB-P1241661, a support is provided in this order with a silver halide emulsion layer and a layer containing physical development nuclei acting as an image receiving layer. After informed exposure and development, the imaged material is used as a printing plate without removing the emulsion layer.

According to a second type of monosheet DTR offset printing plate precursor, a layer of physical development nuclei and a silver halide emulsion layer are provided in this order on a hydrophilic support (mostly anodized aluminum). After exposing and developing according to the information, the imaged material is processed to remove the emulsion layer, leaving the support carrying the silver image, which is used as a printing plate. Such kind of lithographic printing plate is, for example, U
It is described in S-P3511656.

With respect to other printing plates, offset printing plates belonging to the second type of mono-sheet DTR offset printing plates have good printing characteristics, such as high printing durability, good ink receptivity in the printing area and non-printing areas. Is required to have non-ink receptivity (no toning). Further, it is desired that the printing plate has a high resolution.

Offset printing plates belonging to the second type of mono-sheet DTR offset printing plates have good printing properties in most cases. In order to improve the resolution of these types of printing plates, a dye which gives a sharpness to the emulsion layer of these printing plate precursors (sharpening dyes) is used.
e) can be added, but results in a loss of sensitivity. That is a serious drawback.

JP 05/303206 discloses and improved a printing plate precursor belonging to a second type of monosheet DTR offset printing plate containing a filter dye or pigment in the uppermost hydrophilic colloid layer above the emulsion layer. Claims sharpness and print durability. However, these printing plates have a minimum point seen on the printing plate at a constant exposure which causes an undesired reduction of the reproducible gray value, which is also a significant disadvantage, and a minimum point on the printing from said printing plate. This reduces the screen area to be printed due to the poor match. Thus, there is still room for improvement of this type of printing plate.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an imaging material for making a silver halide diffusion transfer offset printing plate having good consistency and high resolution between the printing plate and the print. The image forming material has as little loss of sensitivity as possible.

It is another object of the present invention to provide a method of manufacturing an offset plate with said imaging material having better consistency and higher resolution between the printing plate and its print.

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

[0014]

According to the present invention, there are provided (i) an image receiving layer containing physical development nuclei, and (ii) a silver halide emulsion having a water-permeable relationship with the image receiving layer. containing a blue or a photosensitive layer sensitive to green light and (iii) said image-receiving layer and the antistress composition in water permeable relationship
An imaging element comprising a stress-resistant composition layer in this order on a hydrophilic surface of a support, wherein the stress-resistant composition layer comprises 0.02 g.
/ M ² -1.0 g / m ² in CI Pigment Red 1
12 (color index 12370) particles,
An imaging element is provided wherein the silver halide emulsion is absorptive to a range of light to which it is sensitive.

According to the present invention, there is also provided a method for producing an offset printing plate by a silver salt diffusion transfer method comprising the steps of: (a) exposing an image-forming material according to the present invention image-wise;
(B) applying an aqueous alkaline solution to the imaging material in the presence of a developing agent and a silver halide solvent; (c) treating the imaging material to remove a layer above the image receiving layer, thereby The silver image formed on the image receiving layer is exposed.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION 0.02 g / m ^{2 to} 1.0 g / m
² , preferably from 0.04 g / m ^{2 to} 0.60 g /
m includes an antistress composition layer containing a non-diffusible dye or pigment particles in an amount of ^2, by using an image forming material having absorptivity for a range of optical silver halide emulsion is susceptible, A lithographic printing plate according to the DTR method having a good resolution and a high resolution with little loss of sensitivity of the printing plate precursor is obtained.

The non-diffusible dye or pigment particles are mostly solid particles, but can also be liquid, ie, emulsified particles. The number average particle size of the particles, expressed as the diameter of a sphere having an equivalent volume, is preferably from 0.01 μm to
0.5 μm, more preferably 0.05 μm to 0.1 μm.
25 μm.

The preparation of particles having the stated particle size is well known to those skilled in the art. For example, the dispersion of the non-diffusible dye or pigment can be obtained by the following steps.

In the first step, a high shear mixer (eg, U
LTRA TURRAX, KOTTHOFF MISCHSIRENE or DISSOLV
ER) with water or a water-miscible solvent (e.g. ethanol) in the presence of a surfactant in an amount of 0.10 g / l to 25 g / l, more preferably 0.30 g / l to 7.5 g / l. Preferably in a solution of water containing 10 g / l to 700 g / l,
More preferably, by stirring the non-diffusible dye or pigment in an amount of from 30 g / l to 500 g / l
A pre-dispersion having particles with a particle size of ２０20 μm is obtained. The time of said stirring is not very critical, but should be long enough to obtain a homogeneous predispersion. Actually, 120 seconds to 1800 seconds, more preferably 360 seconds to
A time of 1200 seconds applies. The temperature of the agitation is not critical, but for practical reasons is between 15C and 50C, more preferably between 20C and 35C.

In the second step, the preliminary dispersion is milled (pulverized) until a desired particle size is obtained. Suitable mills are, for example, horizontal pearl mills
(Eg, DYNOMILL and COBALL-MILL), ball mills, sand mills, vertical mills and the like. The temperature of the milling is not critical, but for practical reasons is between 15C and 50C, more preferably between 20C and 35C. The time of milling is determined by the technical characteristics of the mill and will be apparent to those skilled in the art. Actually, the time is 120 seconds to 3600 seconds, preferably 300 seconds to 2400 seconds.
Could be seconds.

As the non-diffusible dye or pigment having a light absorbing property to which the silver halide emulsion is sensitive, a dye or pigment suitable as an antihalation dye is preferable. Said dyes or pigments are absorptive to light to which the silver halide emulsions are sensitive either intrinsically or by spectral sensitization. For imaging materials comprising silver halide emulsions sensitive to blue or green light, said non-diffusible dyes or pigments whose silver halide emulsions are absorptive to sensitive light are sold under the trade name Helioetchtappie
CI Pigment Red 112 (Color Index No. 12370) sold by BAYER AG Germany under rotBL.

The stress-resistant composition layer is composed of one or more layers and / or at least one of them containing a non-diffusible dye or pigment which has a light-absorbing ability to the silver halide emulsion. However, for practical reasons it is preferred that the composition layer consist of one layer.

The stress-resistant composition layer according to the present invention has a thickness of 0.60 to 0.60.
In an amount of 1.75 g / m ² , more preferably 0.80 to
It is preferred to include unhardened gelatin as binder in an amount of 1.25 g / m ² .

Preferably, at least 50%, more preferably at least 75%, most preferably at least 90% of said unhardened gelatin belongs to one or more gelatin species, of which a 10% by weight aqueous solution (36 ° C., pH 6) is 100%.
35 mPa.s at a shear rate of 0 s ^-1 . s, less preferably 30 mPa.s. s.

The stress-resistant composition layer can contain one or more unhardened gelatins, and a 10% by weight aqueous solution thereof (36 ° C.,
pH 6) is 35 mPa.s at a shear rate of 1000 s- ¹ . s
Although having a lower viscosity, for practical reasons the composition layer preferably contains only one such gelatin.

The stress-resistant composition layer may have a thickness of 0.2 to 10 μm to improve the diffusion of the processing solution through the stress-resistant composition layer.
Small particles having an average diameter of m (eg matting agents) can be included.

The stress-resistant layer according to the invention must be in water-permeable relationship with the image-receiving layer in the imaging element. Layers in water-permeable contact with each other are layers that are adjacent to each other or that are merely separated from each other 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 compounds (eg, developing agents or complexed silver) or water contained in the aqueous solution.

The imaging element is preferably prepared by coating different layers on the hydrophilic side of the support. Alternatively, different layers can be laminated to the image receiving layer from a temporary base that holds the layers in reverse order as described in US-P 5,068,165.

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

Such a hydrophilic binder is, for example, EP-A45
0199, which is incorporated herein by reference. Suitable cured hydrophilic layers are, for example, EP-A5
And aldehyde-cured partially modified dextran or pullulan as described in US Pat. No. 14,990, which is incorporated herein by reference. Further suitable hydrophilic layers are, for example, GB-P1419512, FR-P2300354,
US Pat. No. 3,971,660, US Pat. No. 4,284,705, E
Consist of polyvinyl alcohol cured with tetraalkyl orthosilicate as described in P-A405016 and EP-A450199 (these documents are incorporated herein by reference), preferably SiO ₂ and / or Ti
O ₂ , wherein the weight ratio between the polyvinyl alcohol and the tetraalkyl orthosilicate is 0.5 to 5
Is a layer.

The flexible support may be opaque or transparent, such as a paper support or a resin support. When a paper support is used, one coated on one or both sides with an alpha-olefin polymer is preferred. Organic resin supports such as poly (ethylene terephthalate) films or poly-alpha-olefin films can also be used. The thickness of such an organic resin film is 0.0
It is preferably from 7 to 0.35 mm. These organic resin supports are preferably coated with a hydrophilic adhesive layer that can contain water-insoluble particles such as silica or titanium dioxide.

The hydrophilic surface of the support is preferably a hydrophilic metal support (for example, aluminum foil).

The aluminum support of the imaging element for use according to the present invention can be made from pure aluminum or an aluminum alloy (the aluminum content is at least 95%). The thickness of the support is usually from about 0.13 to about 0.50 mm.

The process for producing aluminum or aluminum alloy for lithographic offset printing involves the following steps: graining (graining), anodizing, and optionally sealing the foil.

Roughening and anodizing of the foil are necessary to obtain a lithographic printing plate which allows to produce high quality prints according to the invention. Sealing is not required, but can further improve the printing results. Preferably, the aluminum foil has a roughness with a CLA value of 0.2-1.5 μm, an anodized layer with a thickness of 0.4-2.0 μm, and is post-treated with an aqueous bicarbonate solution.

According to the present invention, the aluminum foil can be roughened by a conventionally known method. The surface of the aluminum support is 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 In addition, good water retentivity can be imparted to the area forming the non-printing area on the plate surface.

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

The surface roughening is preferably performed mainly by a degreasing treatment for removing fatty substances from the surface of the aluminum foil.

Therefore, the aluminum foil may be subjected to a degreasing treatment with a surfactant and / or an aqueous alkali solution.

Preferably, after the surface roughening, a chemical etching step using an aqueous solution containing an acid is performed. Chemical etching should be at least 30 ° C, more preferably at least 4
It is preferred to work at a temperature of 0 ° C, most preferably at least 50 ° C.

After roughening and, if desired, chemical etching, the aluminum foil is anodized in the following manner.

The current passes through a roughened aluminum foil immersed as an anode in a solution containing an acid. An electrolyte concentration of 1 to 70% by weight can be used within a temperature range of 0 to 70C. To obtain an anodized film weight of ^{_{1~8g / m 2 Al 2 O 3}} · H 2 O, the anode current density is 1
At 50 A / dm ² , the voltage can be varied in the range of 1-100V. Anodized aluminum foil followed by 1
Rinsing may be performed with deionized water in the temperature range of 0 to 80C.

After the anodizing step, sealing may be applied to the anode 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, “Belgisch-N
ederlands tijdschrift voor Oppervlaktetechnieke
n van materialen ”24ste jaargang / januari1
980, titled "Sealing-Kwaliteit en sealing
-Controle van geanodiseerd Aluminum ". There are various types of sealing of porous anodized aluminum surfaces.

Preferably said sealing is EP-A56717
8 by treating a roughened and anodized aluminum support with an aqueous solution containing bicarbonate as described in US Pat.

Preferably, each of the above steps is separated by a rinsing step to avoid contaminating the liquor used in a particular step with that of the preceding step.

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

Following the preparation of the hydrophilic layer of the support as described above, the hydrophilic layer may be immediately coated with a solution containing physical development nuclei, or may be coated with the solution in a later step. You may.

The image receiving layer preferably contains physical development nuclei in an amount of 0.1 mg / m ^{2 to 20} mg / m ² . The image receiving layer containing the physical development nuclei may not contain a hydrophilic binder, but a hydrophilic colloid (for example, polyvinyl alcohol) may be added to improve the hydrophilicity of the surface up to 80% by weight of the total weight of the layer. It is preferred to include a small amount of

Suitable development nuclei for use in accordance with the present invention are sulphides of heavy metals, such as sulphides of antimony, bismuth, cadmium, cobalt, lead, nickel, palladium, platinum, silver and zinc. Particularly preferred development nuclei in connection with the present invention are palladium sulfide nuclei. Other suitable development nuclei are salts such as, for example, selenides, polyselenides, polysulfides, mercaptans, and tin (II) halides. Heavy metals, preferably silver, gold, platinum,
Palladium and mercury can be used in colloidal form.

The photosensitive layer used in accordance with the present invention is any layer comprising a hydrophilic colloid binder and at least one silver halide emulsion (at least one of the silver halide emulsions is photosensitive). There may be.

The photographic silver halide emulsions used in accordance with the present invention are described, for example, in P. Glafkides, "Chimie et Phys.
ique Photographique ”, Paul Montel, Paris (19
67), GF Duffin, “Photographic Emulsion
Chemistry ", The FocalPress, London (196
6) and VL Zelikman et al., “Making and Coa
ting Photographic Emulsion ”, The Focal Press
, London (1966) according to various methods.

For use according to the present invention, the silver halide emulsion is preferably composed mainly of silver chloride, and the fraction of silver bromide can be present in the range of 1 mol% to 40 mol%. Most preferably at least 73 mol%
Silver chloride, 1.5 mol% to 25 mol% of silver bromide,
A silver halide emulsion containing 0.005 mol% to 2 mol% of silver iodide is used.

The average grain size of the silver halide grains is 0.10 to
It can range from 0.70 μm, preferably from 0.25 to 0.45 μm.

Preferably during the precipitation step iridium and / or
Or a rhodium-containing compound or a mixture of both is added. The concentration of these added compounds was 1 m AgNO ₃
10 ^-8 to 10 ^-3 mol, preferably AgNO
₃ The range is 10 ^-7 to 10 ^-5 mol per 1 mol.

During the chemical ripening step, the emulsion contains a sulfur-containing compound,
For example, it can be chemically sensitized by adding allyl isothiocyanate, allyl thiourea and sodium thiosulfate. A reducing agent such as BE-P
The tin compounds described in US Pat. Nos. 4,934,664 and 5,686,687, and derivatives of aminomethane-sulfonic acid or polyamines such as diethylenetriamine can be used as chemical sensitizers. Other suitable chemical sensitizers are gold, platinum,
Noble metals and noble metal compounds such as palladium, iridium, ruthenium and rhodium. This method of chemical sensitization is described in R. KOSLOWSKY, Z. Wiss. Photogr. Photophys. P
hotochem. 46, 65-72 (1951).

Apart from the negative working silver halide emulsions preferred for high photosensitivity, it is also possible to use direct positive silver halide emulsions which produce a positive silver image in the emulsion layer and a negative image in the image receiving layer.

Suitable direct positive silver halide emulsions for use in accordance with the present invention are silver halide emulsions which are pre-fogged or which primarily form an internal latent image.

The silver halide emulsion of the DTR material can be spectrally sensitized according to the spectral emission of the exposure source, for which the DTR material is designed.

Suitable sensitizing dyes for the visible spectral region are described by FM Hamer, "The Cyanine Dyes and Rel
ated Compounds ", 1964, John Wiley & Sons
And methine dyes as described in Dyes which can be used for this purpose include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, isopolar cyanine dyes, hemicyanine dyes, styryl dyes and hemioxonol dyes. Particularly useful dyes are those belonging to the cyanine dyes, merocyanine dyes, complex merocyanine dyes.

In the case of a conventional light source (for example, tungsten light), a green sensitizing dye is required. In the case of exposure with an argon ion laser, a blue sensitizing dye is mixed. In the case of exposure with a red light emitting source (eg, LED or HeNe laser), a red sensitizing dye is used.
In the case of semiconductor laser exposure, special spectral sensitizing dyes suitable for the near infrared are required. Suitable sensitizing dyes are described, for example, in U.S. Pat.
56,29555939,3482978,355297
4,357,921,3582,344,3623881
And 3695888.

Preferred blue sensitizing dyes, green sensitizing dyes, red sensitizing dyes and infrared sensitizing dyes in connection with the present invention are EP-A
554585.

A so-called supersensitizer can be used in combination with a red or infrared sensitizing dye to increase the sensitivity in the red or near infrared region. A suitable supersensitizer is Resea
rchDisclosure Vol 289, May 1988, item
28952. The spectral sensitizer can be added to the photographic emulsion in the form of an aqueous solution, a solution in an organic solvent or in the form of a dispersion.

The silver halide emulsions can contain usual emulsion stabilizers. A suitable emulsion stabilizer is azaindene, preferably tetra- or penta-azaindene,
Particularly, those substituted with a hydroxy or amino group.
Compounds of this kind are described in BIRR's Z.Wiss. Photogr. Photoph
ys. Photochem. 47, 2-27 (1952). Other suitable emulsion stabilizers are heterocyclic mercapto compounds, especially substituted or unsubstituted 1-phenyl-5-mercapto-tetrazole, especially the amide group -NR ₁ -C
O—R ₂ or —NR ₁ —SO ₂ —R ₂ (wherein R ₁ represents hydrogen or C ₁ -C ₄ alkyl, and R ₂ represents C ₁ -C ₈
Represents a hydrocarbon group selected from the group consisting of alkyl, aryl, and alkenyl, wherein the hydrocarbon group is -CO
Substituted by an OM group or a —SO ₃ M group, where M is hydrogen,
1-phenyl-5-mercapto-tetrazole substituted by a metal cation or an ammonium group).

A hydrophilic colloid (usually a protein, preferably gelatin) can be used as a binder in the silver halide emulsion layer related to the present invention. However, gelatin can be partially or completely replaced by synthetic, semi-synthetic, or natural polymers. Preferably the silver halide emulsion layer contains at least one gelatin species, a 10% by weight aqueous solution (36 ° C., pH 6) of 20 mP at a shear rate of 1000 s ⁻¹ in combination with a higher viscosity gelatin.
a. s. Preferably, the weight ratio of said low viscosity gelatin to higher viscosity gelatin is greater than 0.5.

Preferably, the gelatin layer is not substantially hardened. Substantially not cured means that such a gelatin layer is coated on a primed polyethylene terephthalate film base at a dry thickness of 1.2 g / m ² and has a 35% R.C. H. Means that the gelatin layer dissolves at 95% by weight or more in 5 minutes when immersed in water at 30 ° C. for 3 days.

The silver halide emulsion can contain a pH controlling component. Preferably, at least one layer containing gelatin is coated at a pH value above the isoelectric point of gelatin to avoid interaction between the gelatin-containing coating layer and the intermediate layer described below. More preferably, the gelatin layer adjacent to the intermediate layer has a pH above the isoelectric point of gelatin.
Coated with value. Most preferably, all gelatin containing layers are coated at a pH value above their gelatin's isoelectric point. Other ingredients such as antifoggants, development accelerators, wetting agents, and hardeners for gelatin can be present. The silver halide emulsion layer can contain a light-blocking dye that absorbs scattered light and enhances image sharpness. Suitable light absorbing dyes are described in US-P 4,092,168, US
-P4311787 and DE-P2453217.

Further details on the composition, preparation and coating of silver halide emulsions suitable for use in accordance with the present invention can be found in, for example, Product Licensing Index, Vol.
December 1971, Publication 9232, 107-1
It can be found on page 09.

Preferably, the imaging element comprises an intermediate layer between the image-receiving layer on the hydrophilic side of the support and the photosensitive layer (packet) to facilitate removal of said layer (packet), The processing of the imaging material exposes the silver image formed in the image receiving layer.

In one embodiment, the intermediate layer comprises at least one non-protein hydrophilic film forming polymer, for example, polyvinyl alcohol, and optionally EP-A-410.
Comprising an antihalation dye or pigment as described in 500, it is a water-swellable intermediate layer coated at a ratio of 0.01 to 2.0 g / m ^2.

In another embodiment, the intermediate layer is made by polymerization of at least one ethylenically unsaturated monomer,
This is a layer containing a hydrophobic polymer having an average particle size of 0.2 μm or more. Preferably, the intermediate layer contains the hydrophobic polymer beads in a dry state up to 80% of the total amount. Further details are described in EP-A 483 415.

In yet another embodiment, the intermediate layer has a thickness of 0.1 μm.
It is a layer containing particles of a water-insoluble inorganic compound having a number average particle size of m or more. Preferably, said intermediate layer comprises said water insoluble inorganic compound in an amount of at least 0.1 g / m ^2.
Further details are described in EP-A-94203779.7.

In yet another embodiment, the intermediate layer is a layer containing particles of an alkali-insoluble non-polymerizable organic compound having a melting point of at least 50 ° C., wherein said particles are 0.1 μm to 10 μm.
It has a number average particle size of μm. Preferably, said intermediate layer comprises said alkali-insoluble non-polymerizable organic compound in an amount of at least 0.1 g / m ² .

An auxiliary intermediate layer, which may be present between the silver halide emulsion-containing layer and one of the intermediate layers, comprises an antihalation dye or pigment, a developing agent, a silver halide solvent, a base precursor, and an anticorrosive. One or more components such as anionic substances may be mixed. Preferred auxiliary intermediate layers have a thickness of between 0.2 μm and ² μm, and between 0.02 g / m ² and
A layer containing a hydrophilic colloid binder and an antihalation dye or pigment in an amount of 1.0 g / m ² .

When the imaging element is produced by laminating a layer packet containing a photosensitive layer on an image receiving layer, the intermediate layer is provided on the photosensitive layer, the intermediate layer being the upper layer.

According to the present invention, the image-forming material can be information-wise exposed in an apparatus according to its specific application.
A wide selection of cameras for exposing the photosensitive silver halide emulsion is available on the market. Horizontal, vertical and darkroom type cameras and contact exposure equipment can be used to suit any particular type of electronic copying operation. The imaging element according to the invention can also be exposed, for example, with the aid of a laser recorder and a cathode ray tube.

In order to enjoy the beneficial effects of the present invention,
The imaging element is exposed to light of a wavelength that is absorbed by said non-diffusible dye or pigment, which has an absorption for a range of light to which the silver halide emulsion is sensitive.

According to the present invention, a silver image is formed in the light-sensitive layer, and the formed non-reduced silver halide or complex is diffused from the light-sensitive layer to the image-receiving layer in accordance with an image, and is formed therein. To form a silver image, development and diffusion transfer of the informed exposure of the imaging element is performed with the aid of an aqueous alkaline solution in the presence of a developing agent and a silver halide solvent. Developing agents and / or silver halide solvents can be incorporated into the aqueous alkaline solution and / or into the imaging element.

Preferably, the silver halide solvent is used in the aqueous alkaline solution in an amount of 0.05% to 5% by weight, more preferably 0.5% to 2% by weight. The silver halide solvent which acts as a complexing agent for the silver halide is preferably a water-soluble thiosulfate or thiocyanate, such as sodium, potassium or ammonium thiosulfate and sodium, potassium or ammonium thiocyanate.

Further, silver halide solvents which can be used in connection with the present invention include, for example, sulphite, amine, 2-mercaptobenzoic acid, cyclic imide compounds (eg uracil),
5,5-dialkylhydantoins, alkyl sulfones and oxazolidones.

Further, the silver halide solvent for use in connection with the present invention is an alkanolamine. Examples of alkanolamines that can be used in connection with the present invention are those corresponding to the formula:

Embedded image In the formula, X and X ′ independently represent hydrogen, 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. The alkanolamine can be present in the alkaline processing liquid preferably at a concentration of 0.1% to 5% by weight. However, some or all of the alkanolamine can be present in one or more layers of the imaging element.

[0081] Other suitable silver halide solvents for use in connection with the present invention are thioethers. Thioethers which are preferably used are those corresponding to the following general _{^{formula: Z- (R 1 -S) t}} -R 2 -S-R 3 in -Y formulas, Z and Y each independently represents hydrogen, an alkyl group ,
Amino group, ammonium group, hydroxyl, sulfo group,
Represents carboxyl, aminocarbonyl or aminosulfonyl; R ¹ , R ² and R ³ each independently represent an alkylene which may be substituted and optionally contain an oxygen bridge; and t represents an integer of 0-10. Examples of thioether compounds corresponding to the above formula are, for example, US Pat.
83 and EP-A 554585.

Further preferred silver halide solvents are 1,2,2
4-triazolium-3-thiolate, preferably C ₁ -C ₈ alkyl group containing at least three fluorine atoms, C ₁ -C ₈ alkyl group containing C ₄ -C ₁₀ hydrocarbon group and at least three fluorine atoms And / or C ₄ −
C ₁₀ 1 substituted with at least one substituent selected from the group consisting of substituted 4-amino group with a hydrocarbon group,
2,4-triazolium-3-thiolate.

Various combinations of silver halide solvents can be used, at least one silver halide solvent being incorporated into a suitable layer of the imaging element, and at least one other silver halide solvent being added to the developing solution. It is also possible to add

The alkaline processing liquid can 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 imaging or photographic material. When all of the developing agent is contained in the image forming material, the alkaline processing liquid is called an activator or an active liquid.

The silver halide developing agents for use in accordance with the present invention are preferably of the p-dihydroxybenzene type, such as, for example, hydroquinone, methylhydroquinone or chlorohydroquinone, preferably 1-phenyl-3-pyrazolidinone type developing agents. It is combined with an auxiliary developing agent which is the main agent and / or p-monomethylaminophenol. Particularly useful auxiliary developing agents are, for example, 1-phenyl-
3-pyrazolidinone. More preferably, especially when they are incorporated into photographic materials, 1-phenyl-3-, whose water solubility is increased by hydrophilic substituents such as, for example, hydroxy, amino, carboxylic acid groups, sulfonic acid groups and the like. Pyrazolidinone. Examples of 1-phenyl-3-pyrazolidinone 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 also be used.

The preferred amount of the hydroquinone type developing agent is in the range of 0.05 mol to 0.40 mol per liter, and the preferred amount of the second developing agent is 1.0 mol per liter.
The range is from 8 × 10 ^{-3 to} 2.0 × 10 ^-1 mol.

The aqueous alkaline solution according to the present invention can be combined with another silver halide solvent in an amount of from 40 g to 18 g / l.
It may further contain a sulfite, for example sodium sulfite, in an amount of 0 g, preferably 60 g to 160 g per liter.

The quantitative ranges given for the developing agent, the silver halide solvent and the sulfite are such that these compounds form part of the aqueous alkaline solution or contain them upon application of the aqueous alkaline solution. Apply to the amount of these compounds present as solutes in aqueous alkaline solutions during DTR-treatment, depending on whether they are dissolved from the layer.

Aqueous alkaline solutions suitable for use in accordance with the present invention may be used in an amount of at least 0.3 g / l to prevent the emulsion layer from sticking to transport rollers when the emulsion is swollen with the aqueous alkaline solution. And more preferably at least 0.6 g / l of aluminum ions.

The alkaline processing liquid has a pH of 9-14, more preferably 10-13, but depends on the type of silver halide emulsion to be developed, the intended development time, and the processing temperature.

Processing conditions such as temperature and time may vary over a wide range provided that the mechanical strength of the material being processed is not adversely affected and no decomposition occurs.

The pH of the alkaline treatment liquid can be established by an organic or inorganic alkaline substance or a mixture thereof. Suitable inorganic alkali materials are, for example, hydroxides of sodium and potassium, alkali metal salts of phosphoric acid and / or silicic acid, such as trisodium phosphate, sodium or potassium orthosilicate, metasilicate, hydrodisilicate, and sodium carbonate. . Suitable organic alkali substances are, for example, alkanolamines. In the latter case, the alkanolamine will maintain or help maintain the pH and will act as a silver halide complexing agent.

The aqueous alkaline solution may further contain a hydrophobizing agent to improve the hydrophobicity of the silver image obtained in the image receiving layer. Generally, these compounds contain a mercapto or thiolate group and one or more hydrophobic substituents.
Particularly preferred hydrophobizing agents are DE-A 1228927 and US
-Mercapto as described in P45635410-
1,3,4-thiadiazole, 2-mercapto-5-heptyl-oxa-3,4-diazole, 3-mercapto-5-alkyl-1,2,4-triazole and long-chain (at least 5 carbon atoms) alkyl It is a substituted mercaptotetrazole. The hydrophobizing agents can be used alone or in combination with one another.

These hydrophobizing compounds can be added to the aqueous alkali solution, preferably in an amount of 0.1 to 3 g per liter, preferably in combination with 1-phenyl-mercaptotetrazole, the latter compound being added to the solution ( A small amount of ethanol may be contained to improve the solubility of the compound).
g can be used.

The aqueous alkaline solution can contain other ingredients such as, for example, oxidation preservatives, calcium sequestering compounds, sludge inhibitors, and hardeners (including latent hardeners).

Regeneration of the aqueous alkaline solution by known methods is of course possible irrespective of whether the solution contains a developing agent and / or a silver halide solvent.

Although not often required, development may be stopped with a so-called stabilizing solution, which is preferably an acidic stop bath having a pH in the range of 5-7.

Buffer stop bath compositions comprising a mixture of sodium dihydrogen orthophosphate and disodium hydrogen orthophosphate and having a pH in the above range are preferred.

Development and diffusion transfer can be performed in various ways, for example by rubbing with a roller, by wiping with absorbing means (for example, cotton and sponge stoppers) or by immersing the material to be treated in a liquid composition. You can start. Preferably they are performed on an automatically operated device. They are usually carried out at a temperature in the range of 18 ° C to 30 ° C for a time of 5 seconds to 5 minutes.

After forming a silver image on the hydrophilic surface of the support,
Excess aqueous alkaline solution still present on the base can be removed, preferably by guiding the foil through a pair of squeezing rollers.

The silver image thus obtained in the layer of physical development nuclei is then exposed by treating the imaging element to remove all layers on the layer containing physical development nuclei, whereby The image forming surface of the hydrophilic support is exposed.

According to a particularly preferred embodiment of the present invention, the silver image in the layer of physical development nuclei is exposed by rinsing all layers above the layer containing physical development nuclei with rinsing water.

Although the temperature of the rinsing water can vary widely, it is preferably 30 ° C. to 50 ° C., more preferably 35 ° C.
C. to 45C.

The imaging surface of the hydrophilic side of the support can be subjected to a chemical treatment which increases the hydrophilicity of the non-silver image portions and the lipophilicity of the silver image.

This chemical post-treatment often comprises a finishing agent, including 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 is preferred to work with the so-called lithographic composition.

Suitable ingredients for the finish are organic compounds containing a mercapto group, such as the hydrophobizing compounds described above for alkaline solutions. Preferred compounds correspond to one of the following formulas:

Embedded image

Embedded image In the formula, R ⁵ represents hydrogen or an acyl group, and R ⁴ represents alkyl, aryl or aralkyl. Most preferably used compounds are compounds according to one of the above formulas wherein R4 represents alkyl containing ³ to 16 C atoms. Said hydrophobizing agent is preferably included in the finish in a total concentration of 0.1 g / l to 10 g / l, more preferably in a total concentration of 0.3 g / l to 3 g / l.

Additives for improving the lipophilic ink-repellency of hydrophilic surface areas include acidic polysaccharides such as gum arabic, carboxymethyl cellulose,
Sodium alginate, propylene glycol esters of alginic acid, carbohydrates such as hydroxyethyl starch, dextrin, hydroxyethyl cellulose, polyvinylpyrrolidone, polystyrene sulfonic acid, polyvinyl alcohol and water or poly which is the reaction product of an alcohol with ethylene oxide and / or propylene oxide Glycol. If desired, hygroscopic materials may be added, such as sorbitol, glycerol, tri (hydroxyethyl) ester of glycerol, and funnel oil.

Further, it is preferable to add a surface active compound to the finishing agent. Its concentration can vary over a wide range. The only requirement is that the finish does not show any excessive foaming when the plate is finished. Suitable surfactant compounds are anionic or nonionic surfactant compounds.

Suitable finishing agents as described in US Pat. No. 4,563,410 are compositions comprising a solution of mercaptotriazole in a solution of polyethylene oxide having a molecular weight of 4000. Further suitable finishes are US-A406
2682.

When treatment with the finish is initiated, the surface carrying the silver pattern can be dry or wet. In general, treatment with finish does not take long, usually less than about 30 seconds, which is preferably between 30 ° C and 60 ° C.
Can be carried out immediately after the treatment and the stripping step at a finish temperature in the range of

The finish is applied in various ways, for example by rubbing with a roller, by wiping with adsorption means (for example cotton or sponge stoppers) or by dipping the material to be treated in the finish. be able to. The printing plate image-hydrophobization process has a narrow groove filled with a finish and guides the printing plate to a device that transports the printing plate at the end of the groove between the two squeezing rollers to remove excess liquid. May be processed automatically.

As soon as the hydrophilic side of the support carrying the silver image has been treated with a finish, it can be used as a printing plate.

[0113]

The present invention will be illustrated by the following examples.
The present invention is not limited to these. All parts,
Percentages and ratios are by weight unless otherwise specified.

Example 1 A 0.30 mm thick aluminum foil (AA1050) was
The foil was degreased by dipping the foil in an aqueous solution containing 10% phosphoric acid, followed by etching in an aqueous solution containing 2 g / l sodium hydroxide. The foil is then brought to 35 ° C.
Surface was electrochemically roughened by using alternating current in an aqueous solution containing 4 g / l hydrochloric acid and 4 g / l hydroboric acid at a temperature of 0.6 μm and a mean center line roughness Ra of 0.6 μm.
Was formed. The aluminum plate was then smutted at 60 ° C. for 120 seconds with an aqueous solution containing 30% sulfuric acid. The foil was subsequently subjected to anodization in a 20% aqueous sulfuric acid solution to give 3.0 g / m ² of Al ₂
Forming an anodic oxide film of O ₃ · H ₂ O, 20g / l
Of NaHCO ₃ for 30 minutes at 45 ° C., then rinsed with deionized water and dried.

The image forming material I was 1.1 m as a physical development nucleus.
g / m ² PdS, roughened with a silver receptive layer containing
Obtained by coating an anodized and post-treated aluminum support.

Next, the resulting dried layer has a thickness of 0.1 / m ² .
An interlayer was provided on the dry silver receptive layer from the aqueous composition in such a way as to have a weight of 5 g of polymethyl methacrylate. Said composition comprises: 20% dispersion of polymethyl methacrylate beads in an equal volume mixture of water and ethanol having an average particle size of 1.0 μm 50 ml Helioechtpapierrot BL (BAYER AG, D-5090) Leverkusen, trade name of the dye sold by West Germany) 2.5 g saponin 2.5 g sodium oleyl methyl tauride 1.25 g deionized water 300 ml (pH-value: 5.6)

Next, 2.2 mm per 1 mol of AgX
ol, 1- (3- (2-sulfobenzamide)) phenyl-5-mercapto-tetrazole, a substantially uncured photosensitive negative-working cadmium-free gelatin salt spectrally sensitized to green light Odor (97.98 / 2
/0.02 mol%) A silver emulsion layer was coated on the intermediate layer.
The amount of silver halide provided was equivalent to 2.40 g of silver nitrate per m ^{2 and} the gelatin content of the emulsion layer was 1.58 g / m ^2.
m ² and 21 mPa. s with a viscosity of 0.7 g / m ² and 14 mPa.s. s of the remaining gelatin.

Finally, 11 mPa. A stress-resistant layer containing 1 g / m ² of gelatin having a viscosity of s was coated on the layer containing the silver halide emulsion.

Helioechtpapier, a non-diffusible dye having a number average particle size of about 0.1 μm and absorbing green light
rot BL, 0.1875 g of silver halide emulsion containing layer
An imaging material II was obtained in the same manner as the imaging material I, except that the amount containing Helioechtpapierrot BL / m ² was added to the layer containing the silver halide emulsion.

Each of the stress-resistant layers was 0.0625 g / m
² , 0.125 g / m ² or 0.1875 g / m ² H
Helioec in an amount that contains elioechtpapierrot BL
Imaging materials III, IV and V were obtained in the same manner as imaging material I, except that htpapierrot BL was added to the stress resistant layer.

The image forming material is placed in close contact with a test target having a line of dots of the same size in one line and dots of different sizes in different lines,
It was exposed with a plate making camera through it. In the next step, each imaging element was dipped in a freshly made developing solution having the following composition for 10 seconds at 24 ° C .: carboxymethylcellulose 4 g sodium hydroxide 22.5 g anhydrous sodium sulfite 120 g hydroquinone 20 g 1-phenyl-4- Methyl-3-pyrazolidinone 6 g Potassium bromide 0.75 g Anhydrous sodium thiosulfate 8 g Ethylenediaminetetraacetic acid tetrasodium salt 2 g Make up to 1000 ml with deionized water. pH (24 ° C.) = 13

Diffusion transfer was continued for 30 seconds to form a silver image in the image receiving layer.

To remove the developed silver halide emulsion layer and interlayer from the aluminum foil, the developed mono-sheet DTR material was applied to LP82 (Agfa-Gevaert, trade name of a developer sold by Belgium). 4
Rinse with water jet at 0 ° C. for 4 seconds.

Next, the image forming surface of the aluminum foil was
Guided through the finish at 30 ° C. for a second to enhance the water receptivity of the non-image areas and render the image areas oleophilic ink receptive.
The finish had the following composition: Gebo (trade name of surfactant sold by Chemische Fabrik Chem-Y, GmbH, Germany) 250 mg polyethylene glycol 3000 100 ml potassium nitrate 12.5 g citric acid 20.0 g 2-mercapto -5 - heptyl - oxa-3,4 - 1000 ml to at diazole _{2.0g NaH 2 PO 4 · 2H 2} O 20.0g 5- bromo-5-nitro-1,3-dioxane 200mg sodium hydroxide 13.0g water I do. pH (20 ° C.) = 5.9

The printing plate thus produced was mounted on the same offset printing press (HEIDELBERGGTO-46) and used for printing under the same conditions. Anchor / L
Industrial A sold by ithemko Inc., Florida
QUA TAME 7035E as a humidifying solution
K + E 125 sold by Kast + Ehinger, AG, Germany, was used as the ink at a 5% concentration in an aqueous solution containing 5% isopropanol. A compressed rubber blanket was used.

The results are shown in Table 1 below. a) Match: The minimum observable dot difference (μm) between the printing plate and the copy (number average of 6 experiments) b) Sensitivity: (Density = (Dmax + Dmin) / LogE for 2) c) Resolution: the size of the point where the positive and negative points have the same size at the same exposure

From the results in Table 1, it was found that Helioechtpap was added to the stress-resistant layer.
0.0625 g / m ² and 0.12 for ierrot BL, respectively
5 g / ^{m 2} or 0.1875g / ^{m 2} imaging element containing (the imaging element III by the inventors, IV and V) printing plate obtained from Helioechtpapierrot in the silver halide emulsion layer
It has the same value in resolving power as an imaging material containing no Helioechtpapierrot BL in the stress-resistant layer , such as an imaging material containing 0.1875 g / m ^{2 of} BL (Comparative Material II), but with a loss of sensitivity. It turns out that there is less.
Further, the image forming materials III, IV and V are comparative image forming materials I and
It is shown to be more consistent than II. This is especially so in imaging material V.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Paul Copan Sepceptrat, Mortzere, Belgium 27 Inside Agfa Geverth na Mroseze Bennacht Chap (56) References JP 5-303206 (JP, A) JP-A-6-236038 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03F 7/07, 7/00, 7/0004

Claims (7)

(57) [Claims] (1) An image receiving layer containing physical development nuclei, (i)
i) a light-sensitive layer sensitive to blue or green light containing a silver halide emulsion having a water-permeable relationship with the image-receiving layer, and (iii) a water-permeable relationship with the image-receiving layer. An image-forming material comprising a stress-resistant composition layer containing a stress-resistant composition in this order on a hydrophilic surface of a support, wherein the stress-resistant composition layer is 0.02 g / m ^{2 to} 1.0 g / m ² . C in an amount of m ²
I Pigment Red 112 (Color Index 123
70. An imaging element comprising the grains of 70), wherein the imaging element is absorptive to light in the range in which the silver halide emulsion is sensitive. 2. The non-diffusible dye, wherein the non-diffusible dye having an absorptivity to light to which a silver halide emulsion is sensitive is 0.04 g / m 2.
An imaging element according to claim 1, which is used in an amount of ^{2 ~0.60g} / ^{m 2.} 3. The number average particle diameter of the particles is 0.01 μm or more.
3. The image forming material according to claim 1, which has a thickness of 0.5 [mu] m. 4. The particle having a number average particle size of 0.05 μm or less.
4. The image forming material according to claim 3, which has a thickness of 0.25 [mu] m. 5. The composition according to claim 1, wherein the stress-resistant composition layer is 0.60 to 1.7.
5. An imaging element according to claim 1, comprising uncured gelatin as binder in an amount of 5 g / m < ² >. 6. At least 50% by weight of the unhardened gelatin belongs to one or more gelatin species, and a 10% by weight aqueous solution (36 ° C., pH 6) of 35 mPa.s. An imaging element according to claim 5 having a viscosity lower than s. 7. A method for producing an offset printing plate by a silver salt diffusion transfer method comprising the following steps: (a) The CI Pigment Red 112 (color) having a silver halide emulsion absorbing light in a sensitive range. Imagewise exposing the imaging material of any of claims 1 to 6 with light of a wavelength absorbed by the index 12370), (b) imaging the aqueous alkaline solution in the presence of a developing agent and a silver halide solvent. Applying to the material; (c) treating the imaging material to remove the layer above the image receiving layer, thereby exposing the silver image formed on the image receiving layer.