JPH07110578A - Production of silver salt photosensitive sheet and silver salt photosensitive sheet - Google Patents

Abstract

PURPOSE:To provide a photosensitive sheet excellent as an ornamental or display material and further to provide a silver salt offset printing plate excellent in printing durability and picture reproducibility in the monosheet-type diffusion- transfer silver salt photosensitive sheet with an anodized aluminum plate as the substrate. CONSTITUTION:A physical development nucleus and a silver halide photosensitive layer are formed on an anodized aluminum substrate to constitute a diffusion-transfer silver salt photosensitive sheet. The anodic oxide film of the photosensitive sheet is formed by using an electrolyte contg. sulfuric acid to anodize the substrate by AC electrolysis, allowing the substrate to react with an aq. metallic ion-contg. soln. to form a physical development nucleus and further providing a silver halide photo-sensitive layer thereon, and the physical development nucleus is formed in the pore of the anodic oxide film.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a silver salt photosensitive plate, and more particularly to a silver salt photosensitive plate suitable for a silver salt offset printing plate by a silver salt diffusion transfer method.

[0002]

2. Description of the Related Art Conventionally, in the general printing field, an aluminum plate was used as a support, and a diazo photosensitive composition, an azide photosensitive composition or a photopolymer photosensitive composition was applied in a thin layer on the so-called PS. Plates are widely used as offset printing plates. After exposure, the PS plate elutes and removes the non-image area, and uses the anodized surface of aluminum for the non-image area, and has excellent printing performance such as water retention and printing durability.
There is a problem that the light sensitivity is low, a large output light source is required for laser direct plate making, etc., and the sharpness of the image is poor, so that only contact baking using a film can be used. Recently, an electrophotographic OPC printing plate in which an electrophotographic photosensitive layer is provided on an aluminum support, a toner image is developed, and then a non-image portion is dissolved and removed by using a toner as a resist has come into practical use. This printing plate has high photosensitivity, uses the anodized surface of aluminum in the non-image area, and has excellent printing performance such as water retention and printing durability, and it is beginning to be put to practical use in laser direct plate making for newspapers. Since this method requires corona charging, not only is it difficult to put it into practical use in contact baking, but also the holding time of the charge is limited, making laser direct plate making difficult in high-quality printing such as general printing. Further, there is a problem that the plate making apparatus is complicated and expensive because it requires steps such as corona charging and toner development.

On the other hand, in the field of light printing, it has excellent photosensitivity,
Electrophotographic zinc oxide printing plates and silver salt printing plates using the silver salt diffusion transfer method have been put to practical use, but a paper or film is used for the support, and the photosensitive layer is directly hydrophilized in the non-image area. However, the water retention was poor and the printing durability was limited.

The silver salt lithographic printing plate using the silver salt diffusion transfer method (DTR method) is described in "Photographic Silver" by Andre Lot and Edith Weide, published by Focal Press, London New York (1972). Halide Diffusion Processes ", pages 101-130, for some examples.

As described therein, in a lithographic printing plate using the DTR method, a two-sheet type in which a transfer material and an image receiving material are separately provided, or they are provided on a single support. Two types of mono-sheet type are known. For a two-sheet type lithographic printing plate, see JP-A-57-1
It is described in detail in Japanese Patent No. 58844. For mono-sheet type, Japanese Patent Publication No. 48-30562,
51-15765, JP-A-51-111103,
It is described in detail in each of the publications such as No. 52-150105. All were developed for light printing and had limited printing durability.

The silver salt type lithographic printing plates using aluminum as a support are disclosed in JP-A-57-118244 and 57-57.
-158844, 63-260491, JP-A-3
It is described in detail in each publication such as No. -116151.
For example, in JP-A-63-260491, a physical development nucleus solution in which silver sol prepared by the curry method is dispersed in gelatin is applied on a roughened and anodized aluminum support to form a physical development nucleus layer. A silver salt printing plate is described which is formed and provided with a silver halide photosensitive layer thereon.
In this printing plate, unexposed silver halide is converted into a soluble silver complex by development in the presence of a developing agent and a silver halide solvent, diffuses into a physical development nucleus layer below to form a silver image, and the exposed silver halide is It is chemically developed and remains on the photosensitive layer, and then the entire photosensitive layer is dissolved and removed to leave a silver image, thereby obtaining a printing plate. Therefore, although the anodized surface of aluminum can be used and is excellent in water retention, the physical development nuclei are in the form of particles and are wrapped in a hydrophilic polymer, and even if a silver image is deposited, it does not adhere to the aluminum surface. There was a problem that the adhesiveness was poor and sufficient printing durability could not be obtained. In addition, when the photosensitive layer is eluted after development, the image peels off together with the physical development nucleus layer, and there is a problem of lack of stability.

[0007]

DISCLOSURE OF THE INVENTION The present invention relates to a silver salt photosensitive plate having aluminum as a support, in which the method for forming physical development nuclei is improved to improve the reproducibility of an image and when used in an offset printing plate. The purpose is to improve printing durability.

[0008]

Means for Solving the Problems The present inventors have diligently studied the above problems. As a result, using an electrolytic solution containing sulfuric acid, the aluminum support anodized by an alternating current electrolytic method, by contacting an aqueous solution containing physical development nucleus metal ions, found that physical development nuclei are formed, It was found that by utilizing this, a DTR method photosensitive plate excellent in image reproducibility and printing durability can be obtained.

That is, according to the present invention, an electrolytic solution containing sulfuric acid is used, and at least the anodic oxide film side of an aluminum support having an anodic oxide film formed by an alternating current electrolysis method on the surface thereof contains a metal ion which constitutes a physical development nucleus. A method for producing a silver salt photosensitive plate is characterized in that a physical development nucleus is formed by contacting with a solution and a silver halide photosensitive layer is provided thereon. Furthermore, the present invention is a silver salt photosensitive plate characterized in that the physical development nuclei are formed in the pores of the anodic oxide film.

Next, the method of manufacturing the silver salt photosensitive plate of the present invention and the silver salt photosensitive plate using the same will be described in detail.

The aluminum plate used for the support of the present invention includes pure aluminum and various metals such as silicon, magnesium, iron, copper, zinc, manganese, chromium,
An aluminum alloy plate containing a small amount of titanium or the like is suitable.
A trace amount of impurity metal contained in aluminum or a small amount of arbitrarily added metal has a great influence on the size, shape and distribution of the pits of the grain obtained by electrolysis, and also on the strength of the aluminum plate. give.

In order to use the aluminum plate as a support for a photosensitive plate, it is generally surface-treated before coating the photosensitive layer. In the surface treatment, degreasing and anodic oxidation treatments are generally carried out. Particularly, in the case of an offset printing plate support, treatments such as roughening and desmutting are further added during degreasing and anodization. These treatments are usually performed continuously using an aluminum coil, and water washing is added between the treatments as needed. Next, a method for manufacturing a support will be described in the order of processing steps using a support for an offset printing plate as an example.

The degreasing treatment removes an oxide film or the like formed by contact with oil or air during rolling of the aluminum surface to expose a clean aluminum plate surface so that the subsequent steps can be uniformly processed. Is given. Examples of the degreasing method include solvent degreasing with trichloroethylene, perchlorethylene, etc., alkaline degreasing with sodium hydroxide, sodium carbonate, sodium metasilicate, trisodium phosphate, tetrasodium pyrophosphate, soap, etc., or a mixture thereof. There are methods such as emulsion degreasing in which a surfactant, kerosene, triethanolamine, sodium hydroxide and the like are combined, and electrolytic degreasing called finish degreasing that removes contamination that cannot be removed by the above chemical degreasing. Fork ultrasonic cleaning is also effective.

Next, a roughening process is performed. The roughening treatment gives unevenness to the surface and directly contributes to the improvement of the adhesiveness of the photosensitive layer by the anchor effect.However, in the offset printing plate, printing such as printing durability and water retention printing image quality is performed. Since it affects the basic performance of, various methods are now in practical use for improving these performances.
That is, mechanical graining methods such as brush graining, ball graining and liquid honing, chemical graining methods by chemical etching with hydrochloric acid or nitric acid, or electrolysis by electrochemical etching with these acids. A roughening method, or a method of roughening it by combining them is known.

Among them, the electrolytic surface roughening method can finely adjust the shape and surface roughness of the grain depending on the composition of the electrolytic solution and the electrolysis conditions as compared with other methods. It is the center of the roughening method. For example, brush graining and electrolytic surface roughening (described in JP-A-53-123204), chemical etching and electrolytic surface roughening (JP-A-60-208294).
Liquid honing and electrolytic surface roughening (JP-A-60).
-18390 gazette)) and the like are known. The electrolytic surface-roughening method is a preferred method for surface-roughening the silver salt offset printing plate support of the present invention. In the electrolytic surface-roughening method, pits are formed on the aluminum surface, and the size, depth, and distribution of pits can be changed depending on the current density, liquid concentration, liquid composition, liquid temperature during electrolysis.
The shape of the surface is generally expressed by a roughness meter, and its size is suitably center line average roughness; Ra value of 0.3 to 1.0 μ.

Generally, in the electrolytic surface roughening method, an electrolytic solution containing hydrochloric acid or nitric acid as a main component is used, and electrolysis is carried out by applying a direct current or an alternating current (single phase or three phases). In electrolytic surface roughening treatment, it is necessary to supply a large current to a continuously moving aluminum plate strip, so the power feeding method has been devised, and the direct power feeding method in which the power feeding terminal is directly contacted with the aluminum plate, or direct aluminum Connect the power supply between both electrodes, without contacting the power supply terminal with the plate, via the electrolytic solution between the counter electrode, for example, in the case of single-phase alternating current, divide the processing tank into two However, in the case of three-phase alternating current, each of the three-phase terminals is divided into three tanks and connected, and an electrolytic solution is supplied to energize the so-called indirect power supply method (Metal surface technology Vol. 30, No. 10, 1979, P541
~ P546) can also be adopted.

The electric current used for electrolytic surface roughening treatment is single-phase or three-phase commercial alternating current, or 10 to 300 Hz including them.
, Sine wave, square wave, triangle wave, thyristor, etc., part of AC waveform is cut, current of asymmetrical type, positive / negative current ratio is not equal, symmetric sine wave, and non-sine wave , Symmetrical non-sinusoidal wave can be used.

The power supplied to the aluminum plate varies depending on the composition of the electrolytic solution, the temperature, the distance between the electrodes and the like, but in order to obtain a suitable grain as a printing plate, the voltage is generally 1 to
60 V, 5-60 A / dm ² at the current density on the treated surface,
It is used in the range of 50 to 4000 coulombs in terms of electricity. The temperature of the electrolytic solution is preferably 0 to 60 ° C., and the distance between the electrode and the aluminum plate is preferably in the range of 1 to 10 cm.

As the electrolytic solution, nitric acid or a salt thereof, hydrochloric acid or a salt thereof, or an aqueous solution of one kind or a mixture of two or more kinds thereof can be used. Further, if necessary, sulfuric acid, phosphoric acid, chromic acid, boric acid, organic acid, or their salts, nitrates, chlorides, ammonium salts, amines, surfactants, other corrosion accelerators, corrosion inhibitors, stabilization You may use it, adding an agent and the like.

Regarding the concentration of the electrolytic solution, it is preferable that the concentration of the above-mentioned acids is 0.1 to 10% by weight and the concentration of aluminum ions in the electrolytic solution is maintained in the range of 0 to 10 g / liter. In the electrolytic surface roughening treatment, as the electrolysis proceeds, aluminum melts and the acids are consumed.Therefore, while discarding a part of the electrolytic solution, the acids are removed so that the composition of the electrolytic solution does not deviate from the predetermined setting range. It is preferable to install a replenisher for replenishing the electrolyte solution.

The aluminum plate strip electrolytically surface-roughened as described above is sufficiently washed with water, but smut usually adheres to the surface and cannot be removed by only washing with water, and blocks the pits. Desmutting is applied to remove the smut. For the desmutting treatment, an alkaline agent which is usually used for degreasing treatment can be used. Desmutting dissolves the smut and reveals the pit surface. The amount of dissolution depends on the treatment conditions with the electrolytic solution,
0.1 to 1 g / m ² is suitable.

The desmutted roughened aluminum strip is then anodized. In the anodizing treatment, an aluminum oxide film is formed on the aluminum surface, which not only prevents the surface from being denatured, but also significantly improves the surface hardness and improves the printing durability during printing.

Usually, micropores of a porous oxide film are positively used as the anodic oxide film. As an electrolytic solution for producing such a porous oxide film, sulfuric acid, oxalic acid, chromic acid,
Phosphoric acid, etc., or a mixture thereof may be used, and an acid having a low solubility of the produced oxide film is used. Since the anodic oxide film is formed only on the anode, a direct current is usually used as the current.

In the present invention, however, a so-called sulfuric acid alternating current coating is used as the anodizing treatment, in which an electrolytic solution containing sulfuric acid is used and which is anodized by an alternating current electrolysis method.
When electrolysis is performed in a sulfuric acid bath in an alternating current, sulfate ions are reduced and sulfur compounds such as sulfur and hydrogen sulfide are produced in the film or in the micropores (JM Kape; Metal Finis
ing, April, 80 (1974)). When an aluminum support having such a film formed thereon is brought into contact with an aqueous solution of a metal salt, a metal sulfide reacts with the solution to form on the surface or in the micropores. In particular, when metal ions capable of forming physical development nuclei are used in the aqueous metal salt solution, physical development nuclei of metal sulfide can be formed as they are.

In the present invention, as the electrolytic solution containing sulfuric acid, sulfuric acid and a mixture of sulfuric acid and an inorganic acid such as phosphoric acid and chromic acid capable of forming an anodic oxide film, or a mixture of sulfuric acid and an organic acid such as oxalic acid and citric acid. Aqueous solution of can be used.

The electric current of the AC electrolysis method used for the anodizing treatment of the present invention is a single-phase or three-phase commercial AC or a sine wave, a square wave in the range of 1 to 300 Hz including them.
Waveform current with a part of AC waveform cut by triangular wave, thyristor, etc., asymmetric type with unequal positive / negative current ratio, symmetric sine wave, non-sinusoidal wave, symmetric non-sinusoidal wave, etc. can be used . Further, an AC / DC superposed wave in which a direct current is superposed on these currents, an incomplete rectified wave, or a current by a current inversion method in which a negative current is caused to flow periodically can also be used.

The conditions for anodic oxidation are liquid concentration of 1 to 30.
%, The voltage is used in the range of 5 to 100V. The thickness of the anodic oxide film is changed by the net amount of electricity of the anodic current and the time, and is appropriately adjusted depending on the printing durability grade of the printing plate.
0.1 to 3 μm is sufficient. The production amount of the sulfur compound is not necessarily proportional to the thickness, but it is larger as the current density is higher, the temperature is lower, and the bath voltage is higher, and it varies depending on the magnitude of the cathode side current with respect to the anode side current. Further, in the porous anodic oxide film, the anodic oxidation current concentrates in the micropores and grows, so that more sulfur compounds are formed in the micropores than on the surface or in the oxide film. Since coloring is not the purpose in the present invention, the amount of the sulfur compound produced in the anodic oxide film is sufficiently small to form physical development nuclei, and 0.1 g / m ² or less is sufficient.

Next, in the present invention, after anodic oxidation, it is brought into contact with a metal ion-containing solution that constitutes physical development nuclei to perform physical development nucleation treatment.

Examples of physical development nuclei generally used in the DTR method include heavy metals such as silver, gold, platinum, palladium, copper, cadmium, lead, cobalt and nickel, or their sulfides and selenides. Since the reproducibility changes depending on the type of physical development nuclei, the optimum physical development nuclei are selected depending on the type, configuration, application, etc. of the DTR material.

These physical development nuclei are described in the above-mentioned patent publications by reducing the corresponding metal ions to form a metal colloidal dispersion, or by mixing a metal ion solution with a soluble sulfide or selenide solution to form a water-insoluble metal. It can be obtained by making a colloidal dispersion of sulfide or metal selenide, and is used in the form of so-called colloidal particles. Since it is in a particle state, for the purpose of dispersion stability, poly-N-vinylpyrrolidone, gelatin, carboxymethyl cellulose, hydroxymethyl cellulose, as a protective colloid or as a binder,
Polymers such as polyvinyl alcohol, polyacrylamide, and acrylamide-vinylimidazole copolymer are added and coated to form a physical development nucleus layer. For this reason, nuclei cannot be placed in the micropores of the porous anodic oxide film.

On the other hand, in the present invention, the physical development nuclei are obtained by contacting an aluminum support having an anodized film formed by an alternating current electrolysis method on the surface with a metal ion-containing solution capable of physical development nucleation by a method such as immersion. Precipitate as a metal sulfide. That is, in the present invention, the sulfur compound generated in the micropores of the porous anodic oxide film in advance reacts with the metal invading in the form of ions to form physical development nuclei of metal sulfide.
In the DTR method, the silver ions supplied from the upper silver halide photosensitive layer by development are deposited on the physical development nuclei to form a silver image, so silver is deposited from the physical development nuclei existing in the pores, and the image is It's as if you've rooted in the pores,
A silver image with excellent adhesion can be obtained.

The metal ion source for forming physical development nuclei is an aqueous solution of the above corresponding metal sulfate, nitrate, halide, cyanide or the like, or an aqueous solution obtained by dissolving these in a small amount of acid or alkali. Can be used as alcohol or a mixed solution of alcohol and water. In the present invention, the concentration of the metal ion source compound in the aqueous solution is 0.0
01-0.2 g / l is sufficient.

In the physical development nucleation treatment using the metal ion-containing solution of the present invention, the treatment liquid does not contain a particulate metal colloid and no polymer is added, so that the physical development nuclei are effectively contained in the micropores of the anodic oxide film. It can be deposited and a strong physical development nucleus can be formed.
Further, since only dipping is sufficient for the treatment, it is also possible to carry out a physical development nucleation treatment continuously by anodizing after anodizing at the stage of surface treatment of the aluminum coil. Even if physical development nuclei are formed on the surface of the anodic oxide film outside the micropores, the effect of the present invention is not hindered, but if a large amount is formed, stains may occur during printing. It is preferable to remove the excess liquid by washing with water after.

The support subjected to the physical development nucleation treatment is then provided with a silver halide photosensitive layer. The photosensitive silver halide used in the present invention is selected from commonly used silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodide, silver iodobromide, silver chlorobromoiodide and the like. To be selected. The emulsion type may be either a negative type or a positive type, and a special type described in JP-A-54-48544 using a photosensitive silver halide and a non-photosensitive silver halide emulsion hardly soluble. May be If necessary, an overlayer may be provided in these silver halide photosensitive layers for the purpose of improving image sharpness such as halation prevention.

The photosensitive halide emulsion provided on the physical development nuclei-containing anodic oxide film layer is a silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodide, or iodine prepared by a conventional method. Although any of silver bromide, silver chlorobromoiodide emulsion and the like may be used, silver chloride or those mainly containing silver chloride are preferable. The silver halide emulsion can be subjected to various chemical sensitizations such as noble metal sensitization, sulfur sensitization, reduction sensitization, and sensitization combining these sensitizations, and if necessary, a sensitizing dye such as cyanine. Spectral sensitization can be performed by using a dye such as merocyanine or merocyanine. Further, additives such as antifoggants, stabilizers and surfactants may be contained by known methods. For details of the photosensitive silver halide emulsion and a method for producing the same, reference can be made to the description in JP-A-49-55402.

As the protective colloid of the photosensitive silver halide emulsion, various kinds of gelatin such as acid-processed gelatin, alkali-processed gelatin, gelatin derivatives and grafted gelatin can be used, and polyvinylpyrrolidone, various starches, albumin, polyvinyl alcohol, A hydrophilic polymer compound such as gum arabic or hydroxyethyl cellulose may be contained.

In the DTR type aluminum lithographic printing plate, a silver image is formed by the following procedure. In the imagewise exposed light-sensitive silver halide emulsion layer, unexposed silver halide is converted into a soluble silver complex in the presence of a developing agent and a silver halide solvent, and exposed silver halide is chemically developed. The unexposed portion of the soluble silver complex diffuses into the physical development nuclei layer and forms a silver image in the presence of physical development nuclei. After forming a silver image, the silver halide photosensitive layer is removed and used as a lithographic printing plate.

The developer used in the present invention contains an alkaline substance such as sodium hydroxide, potassium hydroxide, lithium hydroxide, tribasic sodium phosphate, or an amine compound, a preservative such as sodium sulfite and a viscous agent. For example, additives such as carboxymethyl cellulose, antifoggants such as potassium bromide, toning agents such as 1-phenyl-5-mercaptotetrazole, development modifiers such as polyoxyalkylene compounds can be included. As the developing agent used in the present invention, polyhydroxybenzenes and 3-pyrazolidinone are preferable, and these developing agents may be used in a so-called main agent built-in type contained in the plate material constituting layer.

Wash-off for removing the silver halide photosensitive layer can be carried out by washing with running water at a temperature of about 20 to 40 ° C. Further, after wash-off, a plate surface protective agent such as gum arabic may be applied as necessary to protect the plate surface.

[0040]

EXAMPLES The present invention will be described by taking a silver salt offset printing plate as an example.
The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

Example 1 An A1050 type aluminum plate strip having a width of 300 mm and a thickness of 0.2 mm was moved at a processing speed of 1.3 m / min to obtain 50
° C., was dipped for 30 seconds in a 4% aqueous sodium hydroxide solution, washed with water, immersed in the electrolytic cell of the indirect power supply system filled with 1.5% hydrochloric acid 20 ℃, 20A / dm ² from a power source thereto, 50H
A single-phase alternating current of z was applied to each electrode terminal for 45 seconds to roughen the AC electrolytic surface, washed with water, then immersed in a 4% caustic soda aqueous solution at 25 ° C for 30 seconds to desmut, washed with water, then 25 ° C, 15 50% by passing through 90% sulfuric acid for 90 seconds, 5
It was anodized with an alternating current of A / dm ² , washed with water, and then dried to obtain an aluminum support for offset printing plates.

Immediately thereafter, it was immersed in a 0.1% aqueous silver nitrate solution for 1 minute to react with it to perform a physical development nucleation treatment of silver sulfide and then washed with water.

An ortho-sensitized silver chloride gelatin emulsion was added to the thus-obtained physical development nucleation-treated support at a silver content of 1.5 g / m ² and a gelatin content of 1.0 g / m ² . A silver halide photosensitive layer was formed by applying the above-mentioned coating solution and drying to obtain a silver salt offset printing original plate.

Comparative Example For comparison, a gelatin coating solution containing silver colloid (silver: gelatin = 1: 1 weight ratio) prepared by the curry method was applied to the anodized aluminum support of Example 1 to give a composition of
A 05 g / m ² physical development nucleus layer was formed, and Example 1 was formed thereon.
Was coated with silver halide emulsion and dried to obtain a silver salt offset printing original plate.

Next, a standard resolution test chart (USAF) was contact-exposed to the printing plate precursors of Example 1 and Comparative Example, respectively, using a tungsten lamp as a light source, and developed with the following developer (1) at 20 ° C. for 30 seconds. After development, the film was washed in warm water to remove the residual film, and a silver salt offset printing plate was obtained.

Developer (1) Sodium sulfite 50 g / l Hydroquinone 12 g / l Phenidone B 6 g / l Sodium hydroxide 12 g / l Sodium thiosulfate 10 g / l Potassium bromide 1.0 g / l pH 13.0 Phenidone B = 4- Methyl-1-phenyl-3-pyrazolidone

When the image reproducibility of the printing plates thus obtained was compared on the plate surface, it was 80 to 100 in Example 1.
The number of lines / mm, and in the comparative example, 30 to 50 lines / mm, the present invention was found to be excellent. Further, when both plates were simultaneously loaded on an offset printing machine and the printing durability was compared, the present invention was possible up to 50,000 sheets without causing scumming. It was found that the printing plate was missing and the present invention was a printing plate excellent in printing durability.

Example 2 An aluminum support prepared in the same manner as in Example 1 was immersed in an aqueous solution containing metal ions containing 0.01% palladium chloride and 0.05% phosphoric acid for 1 minute and reacted to react it with the physical properties of palladium sulfide. After forming development nuclei, it was washed with water.

A silver halide emulsion similar to that used in Example 1 was coated on the thus-obtained physical development nucleation-treated support and dried to obtain a silver salt offset printing original plate. Further, the printing original plate prepared in this manner was imagewise exposed, developed with the following developer (2) at 20 ° C. for 30 seconds, and washed in warm water after development to remove the residual film, to obtain a silver salt offset printing plate. Obtained. When the printing plate thus obtained was placed on an offset printing machine and printed, no scumming occurred.
I was able to print 10,000 sheets.

Developer (2) Sodium sulfite 50 g / l Hydroquinone 12 g / l Phenidone B 12 g / l Sodium hydroxide 2 g / l Sodium thiosulfate 10 g / l 2-Methylaminoethanol 40 cc / l Potassium bromide 0.5 g / l pH 11.4

Example 3 An A1050 type aluminum plate strip having a width of 300 mm and a thickness of 0.24 mm was moved at a processing speed of 1.3 m / min to obtain 50
After immersing in a 4% caustic soda aqueous solution for 30 seconds at 40 ° C., it is washed with water and then immersed in an indirect power supply type electrolytic cell filled with 2.0% nitric acid at 20 ° C., from which a power source of 40 A / dm ² , 50 H
A single-phase alternating current of z was applied to each electrode terminal for 45 seconds to roughen the AC electrolytic surface, washed with water, then immersed in a 4% caustic soda aqueous solution for 30 seconds to desmut, washed with water, and then 5 ° C at 25 ° C. By passing it through a mixed acid of 5% sulfuric acid and 5% phosphoric acid for 2 minutes, and anodizing it with a direct current of 1 A / dm ^{2 and} an alternating direct current of 60 Hz and an alternating current of 2 A / dm ² (effective value).
It was washed with water and then dried to obtain an aluminum support for offset printing plates. A silver salt offset printing plate was obtained in the same manner as in Example 2 except that this support was used.

Example 4 In Example 3, the anodic oxidation treatment was passed through a mixed acid solution of 2% sulfuric acid and 4% oxalic acid for 1 minute to give an average current density of 3 A / dm.
² , anodizing with a high speed reversal current of 5: 1 duty ratio,
An aluminum support for offset printing plates was obtained in the same manner as in Example 3.

A silver salt offset printing original plate was obtained in the same manner as in Example 2 except that this support was used. When the silver salt offset printing plates obtained in Examples 3 and 4 were made into a plate and evaluated in the same manner as in Example 1, all showed image reproducibility of 100 lines / mm or more and printing durability. The number of sheets was 50,000 or more, and it was found that the silver salt offset printing plate was excellent.

[0054]

INDUSTRIAL APPLICABILITY In a method for producing a DTR type silver salt photosensitive plate using an anodized aluminum plate as a support, an aluminum support anodized by AC electrolysis with an electrolytic solution containing sulfuric acid contains metal ions. Contact the aqueous solution,
By forming physical development nuclei of metal sulfide, a silver salt photosensitive plate having excellent image reproducibility can be manufactured. Further, this photosensitive plate can be used as a silver salt offset printing plate having excellent printing durability.

Claims (2)

[Claims] 1. An electrolytic solution containing sulfuric acid is used, and at least the anodized film side of an aluminum support having an anodized film formed by an alternating current electrolysis method on the surface is contacted with a metal ion-containing solution constituting physical development nuclei. A method for producing a silver salt photosensitive plate, characterized by forming a physical development nucleus and providing a silver halide photosensitive layer thereon. 2. A silver salt photosensitive plate, wherein the physical development nuclei formed by the manufacturing method according to claim 1 are formed in pores of an anodized film.