JP3305488B2 - Lithographic printing plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate using an aluminum plate as a support, and more particularly to a lithographic printing plate using a silver complex salt diffusion transfer method which can be handled substantially in a bright room environment.

[0002]

2. Description of the Related Art A lithographic printing plate using a silver complex salt diffusion transfer method (DTR method) is described in "Photographic Silver Halide." Some examples are described in "Diffusion Processes", pp. 101-130.

As described therein, a lithographic printing plate using the DTR method includes a two-sheet type in which a transfer material and an image receiving material are separated, or a monolithic type in which they are provided on a single support. Two types of sheet type are known.
A two-sheet type lithographic printing plate is disclosed in
This is described in detail in JP-A-158844. For the mono-sheet type, see JP-B-48-30562.
No. 51-15765, JP-A-51-111103
And JP-A Nos. 52-150105.

[0004] A lithographic printing plate using paper as a support is difficult to print with high quality including printing durability due to plate elongation during printing and penetration of moisture. A film support is used for the purpose of improving these problems and improving printing performance. For example, a cellulose acetate film, a polyvinyl acetal film, a polystyrene film, a polypropylene film, a polyethylene terephthalate film, or a composite film obtained by coating a polyester, polypropylene, or polystyrene film with a polyethylene film can be used as the support.

[0005] However, lithographic printing plates using a film as a support are improved in terms of plate elongation and moisture penetration, as compared with paper-based printing plates, but they have improved printing durability, water retention and printing. The problem remains in terms of the ability to hang the plate on the machine.

In order to solve the above-mentioned various problems of the lithographic printing plate using a paper or a film as a support, a lithographic printing plate of a silver salt type using a metal, particularly an aluminum plate as a support has been known. These are described in detail in JP-A-57-118244, JP-A-57-158844, JP-A-63-260491, JP-A-3-116151, and JP-A-4-282295.

JP-A-63-260491, JP-A-3-26049
JP-A-116151 and JP-A-4-282295 disclose that a roughened and anodized aluminum plate is used as a support, a physical development nucleus is supported thereon, and a photosensitive silver halide emulsion is further provided thereon. DT with mono-sheet type with layer
A lithographic printing plate utilizing the R method is described in detail. According to the method, after the lithographic printing plate is subjected to image exposure and DTR development,
The silver halide emulsion layer is removed by washing with warm water to prepare a printing plate. However, these patents are directed to preventing the corrosion of the aluminum plate caused by the contact between the silver halide emulsion and the aluminum plate, and are intended to improve the image quality of the transferred silver image, ink receptivity, and printing durability. It was not enough in point.

In general, the surface of an aluminum support used for a lithographic printing plate is roughened in order to improve wettability (water retention) with a fountain solution during printing and to improve adhesion to a photosensitive layer. Is done. The surface roughening (so-called graining) is performed by mechanically roughening such as ball graining, wire graining, and brush graining, or by chemically dissolving aluminum with chloride, fluoride, or the like. There are known a chemical surface roughening treatment, an electrolytic surface roughening treatment performed by dissolving aluminum electrochemically, and a surface roughening method using these methods in combination. For example, JP-A-48-28123,
No. 53-123204, No. 54-146234, No. 55-25381, No. 55-132294, No. 56-
No. 55291, No. 56-150593, No. 56-28
Nos. 893 and 58-167196, U.S. Pat.
No. 44,510, No. 3,861,917, No. 4,
Nos. 301 and 229. Regarding the surface shape of an aluminum plate, U.S. Pat. No. 2,344,510 discloses a grain structure in which mechanical roughening and electrolytic surface roughening are performed in an overlapping manner, and U.S. Pat. No. 4,301,229 discloses pits. Cumulative frequency distribution and center line average roughness of diameter, U.S. Pat. No. 3,861,917, Roughness Depth, Canadian Patent No. 954,449, Roughness Crest Height and Diameter, West German Patent 1,813, No. 443 describes a difference in elevation of a rough surface.

After performing such a surface roughening treatment, an anodic oxidation treatment is performed in an electrolytic solution such as sulfuric acid, phosphoric acid, nitric acid or a mixture thereof.

As described above, for the surface treatment of an aluminum plate for a printing plate, an extremely large number of surface-roughened aluminum plates having different shapes and structures of the roughened surface have been proposed depending on the type of lithographic printing plate, printing application and the like. However, in the lithographic printing plate targeted by the present invention, in addition to the function of improving the wetting (water retention) with a fountain solution at the time of printing and improving the adhesion to the photosensitive layer, the lithographic printing plate has a halogenated Influence the printing function of the silver film formed on the aluminum surface by the diffusion transfer development of silver, and specifically, the aluminum plate of any surface shape has a problem in terms of ink receptivity and printing durability. There was no known preference. Further, there are no known factors for controlling the diffusion transfer development of silver halide so as to form a silver image having high image quality and favorable printing durability on the aluminum surface.

At present, a PS (Pre-Sensitized) plate in which a photosensitive material layer such as a photopolymer is provided on an aluminum plate widely used in the field of lithographic printing can be handled substantially in a bright room environment. .

The PS plate is manufactured by applying a photosensitive material such as a photopolymer on an aluminum plate which has been subjected to a surface treatment such as a surface roughening treatment and an anodic oxidation treatment and drying. Since the PS plate has sensitivity in the ultraviolet region, it can be handled in safe light substantially free of ultraviolet light, that is, in a substantially bright room, and is exposed to a light source containing a large amount of ultraviolet light. After image exposure with ultraviolet rays, plate making processes such as development, washing, and gumming are performed to complete a printing plate. The undissolved photosensitive layer formed by the developing process forms an image portion, and the portion where the photosensitive layer is removed and the aluminum surface is exposed becomes hydrophilic and a non-image portion is formed.

Although the PS plate is widely used as a lithographic printing plate, it has some problems. At the time of image exposure, the PS plate is exposed to ultraviolet light in close contact with the film. However, since the sensitivity of the PS plate is low, long exposure with strong ultraviolet light is required. Strong ultraviolet light is bad for eyes and is not preferable as a working environment. Further, a large amount of a developing solution containing a high alkali agent, an organic solvent or the like is used in the developing treatment.
The use of such a developing solution is not preferable in the working environment, and the waste liquid generated in a larger amount is a major problem in global environmental conservation. In addition, improvements such as stabilization of quality and rapid processing have been continued.

Under the circumstances described above, with regard to a lithographic printing plate using an aluminum plate as a support by a silver complex salt diffusion transfer method, techniques relating to corrosion prevention on an aluminum surface, a developing method, and the like are described in the above-mentioned patent specification. Although it is disclosed in a book or the like, there is no mention of a lithographic printing plate that can be handled in a bright room environment and has a high image quality and a high printing durability and uses an aluminum plate as a support using a silver complex salt diffusion transfer method. Absent.

[0015]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an object of the present invention is to use a silver complex salt diffusion transfer method which can be handled in a substantially bright room environment and has high image quality and high printing durability. An object of the present invention is to provide a novel lithographic printing plate using an aluminum plate as a support.

[0016]

SUMMARY OF THE INVENTION The above object of the present invention, crude
Planarized and anodized aluminum support and halogen
A lithographic printing plate having a physical development nucleus layer between silver halide emulsion layers
1 mole of silver halide in the silver halide emulsion.
10 ^-8 to 10 ^-3 mol of a water-soluble rhodium salt and halogen
0.2 to 200 mg of organic desensitizer per mole of silver halide
Achieved by a lithographic printing plate characterized by including.

As the water-soluble rhodium salt used in the present invention, conventionally known ones are used. Typically, rhodium monochloride, rhodium dichloride, rhodium trichloride, rhodium ammonium chloride and the like are used. The amount of addition is 10 @ -8 to 1 mol per mol of silver halide.
It may be in the range of 10-3 mol. The rhodium salt is generally preferably used at the time of silver halide precipitation or physical ripening, but may be at any time thereafter.

The organic desensitizer is generally known to be directly used in a positive silver halide emulsion. Specific examples of such organic desensitizers are described in a number of patent specifications and literatures, all of which have the same action in the present invention. 39-20261, 4
0-26751, 43-13167, 45-8
833, 47-8746, 47-10197,
50-37530, JP-A-48-24734, 49-84639, 56-142525, U.S. Pat. Nos. 2,271,229, 2,541,472, and 30.
No. 35917, No. 3062651, No. 31244
No. 58, No. 3,326,687 and No. 3,671,254 can be used. Specific examples are shown below. (A) 1,3-diethyl-1′-methyl-2′-phenylimidazo [4,5-b] -quinoxalinol 3′-indolocarbocyanine iodide (B) pinacryptol yellow (C) 1,1 ′, 3,3, 3 ', 3'-hexamethyl-5,5'-dinitroindocarbocyanine-P-toluenesulfonate (D) 5,5-dichloro-3,3'-diethyl-6,
6 'dinitrothiacarbocyanine iodide (E) 1,1'-dimethyl-2,2'diphenyl-3,3'-indolocarbocyanine bromide (F) 1,1', 3,3'-tetraethylimidazo [4 5,5-b] quinoxanocarbocyanine chloride (G) 5-m-nitrobenzylidene rhodanine (H) 6-chloro-4-nitro-nitrobenzotriazole (I) 1,1'-dibutyl-4,4'-bipyridinium. Dibromide (J) 1,1'-Ethylene-2,2'-Bipyridinium dibromide (K) 4- (Pn-amyloxyphenyl) -2,6
Di (P-ethylphenyl) thiapyrium perchlorate (L) 2-mercapto-4-methyl-5-nitrothiazole (M) 2- (O-nitrostyryl) -3-ethylbenzothiazolium P-toluenesulfonate (N) 2- (P -Nitrostyryl) -quinoline / P-toluenesulfonate (O) phenosafuran (P) pinacryptol green (Q) 2,3-dimethyl-6-nitro-benzothiazolium / P-toluenesulfonate

The amount of the organic desensitizer to be used is selected in the range of 0.2 to 200 mg, preferably 1 to 50 mg, per mol of silver halide. The time of addition is generally added after aging.

The aluminum support used in the present invention is a surface-treated aluminum plate used for printing, which has been subjected to a general surface roughening treatment (so-called graining). In the roughening,
As mentioned above, mechanical surface roughening, chemical surface roughening,
And an electrolytic surface roughening treatment, and a surface roughening method using these methods in combination. In the present invention, a diameter of 0.03
Have at least 500 pits of 0.30 μm per 100 μm ² , and the average diameter of those pits is 0.05 to
A rough aluminum plate of 0.20 μm is preferred.

The inventors of the present invention have found that in a lithographic printing plate to which the present invention is directed, the quality of transfer developed silver which governs image quality, ink receptivity, and printing durability is related to the rough surface state of the aluminum plate. As a result of intensive studies based on the idea that
It has been found that by using a roughened and anodized aluminum plate having a large number of extremely small pits (holes), transfer silver excellent in image quality and very strong for printing is formed. That is, the lithographic printing plate of the present invention using the specific roughened aluminum plate described above is rapidly dissolved in a silver halide emulsion layer by a silver halide solvent contained in a diffusion transfer developer, and Diffused on the surface,
It is presumed that the presence of a large number of small pits produces favorable diffusion control, leading to high image quality. Further, by the preferred diffusion transfer development, transfer silver is formed in a large number of fine pits and has an anchoring effect, and the transfer silver forms a continuous dense lipophilic layer and adheres to the aluminum plate. Transfer silver is not lost even in long printing,
It is considered to show high printing durability.

The roughened and anodized aluminum plate used in the present invention was obtained by using a scanning electron microscope at 50,000.
The photograph can be easily confirmed by a photograph of a magnification of about twice. The pits have a diameter of 0.03 to 0.30 μm, and 500 pits per 100 μm ² , preferably about 1,
There are 000 or more. The upper limit is preferably up to about 15,000. The average diameter of the pits having a diameter of 0.03 to 0.30 μm is 0.05 to 0.20 μm, preferably 0.05 to 0.15 μm. The pit diameter is a dimension when the diameter of a pit having a shape other than a circle is regarded as a circle. The center depth of this pit is 1/3 (0.01 to 0.10 μm) or more of the pit diameter,
Preferably １ ／ (0.015 to 0.15 μm) to 3
(0.03 to 0.90 μm) is desirable.

Japanese Unexamined Patent Publication No. Sho 56-28893 discloses that a plateau (primary structure) and a pit (surface of a plateau) are formed on an aluminum surface by using both mechanical roughening, chemical etching and electrolytic surface roughening. Secondary structure)
The grain of a composite structure consisting of The micro pit of the present invention preferably has a composite structure existing on a large pit (plateau) having an average diameter of 3 to 15 μm. The projected area of the small pit is preferably about 5 to 40%, and the projected area of the large pit (plateau) is 50%.
About 95% is preferable. The center line average roughness (Ra) is preferably in the range of 0.3 to 1.0 μm. The aluminum plate having such a surface shape of the present invention is subjected to mechanical roughening treatment,
It can be relatively easily found by the conditions of the chemical surface roughening treatment, the electrolytic surface roughening treatment, and the anodic oxidation method.
In the case where the number of the small pits is less than 500 or only the large pits without the small pits (plateaus), the pits having an average diameter of 0.30 μm are further 100 μm.
² , Even if the number is 500 or more, only poor ink acceptability and printing durability can be obtained as compared with the lithographic printing plate of the present invention.

The thickness of the anodized layer of the roughened and anodized aluminum plate used in the present invention is about 0.3 to 3.0 μm.
The range of m is preferred. Note that desmutting is preferably performed prior to the anodizing. That is, the surface-roughened aluminum substrate is replaced with 10 to 50% hot sulfuric acid (4%).
0-60 ° C) or dilute alkali (such as sodium hydroxide)
The smut adhered to the surface is removed by the treatment.

After the anodic oxidation treatment, a post-treatment can be performed if necessary. For example, a method of dipping in an aqueous solution of polyvinylphosphonic acid disclosed in British Patent No. 1,230,447 is used. Also,
If necessary, an undercoat layer of a hydrophilic polymer can be provided, but it is selected depending on the properties of the photosensitive layer provided thereon.

The physical development nucleus of the physical development nucleus layer provided on the aluminum support may be a known one usually used in a silver complex salt diffusion transfer method, for example, a colloid of gold, silver or the like, furthermore, palladium, zinc or the like. A metal sulfide obtained by mixing a water-soluble salt such as sulfide with a sulfide can be used. With respect to these details and the production method thereof, techniques described in JP-B-48-30562, JP-A-49-55402, and JP-B-53-21602 can be used.

The silver halide used in the photosensitive silver halide emulsion provided on the physical development nucleus layer includes silver chloride, silver chlorobromide, silver chloroiodobromide and silver chloroiodide. It is a silver halide containing 80 mol% or more, preferably 90 mol% or more of silver chloride.

In the present invention, a negative-type lithographic printing plate can be prepared by using a direct positive silver halide emulsion as the photosensitive silver halide emulsion. The direct positive silver halide emulsion is disclosed in U.S. Pat. No. 3,501,307.

The method of mixing the emulsion may be any of known methods such as forward mixing, reverse mixing, and simultaneous mixing. The emulsion may be prepared by any of the ammonia method, neutral method and acidic method. The size distribution of the silver halide grains may be either monodisperse or heterodisperse, but monodisperse is preferred for uniformity of grain sensitivity. The crystal habit of the particles may be cubic, octahedral, or any other.
The particle size is 1 μm or less, preferably 0.5 μm or less. More preferably, it is 0.3 μm or less. This is because it is necessary to prevent the developed silver particles from being roughened and to make them finer for saving silver.

As the protective colloid of the photosensitive silver halide emulsion, various gelatins such as acid-treated gelatin, alkali-treated gelatin, gelatin derivatives, and grafted gelatin can be used. In addition, polyvinylpyrrolidone, various starches, albumin, polyvinyl alcohol, It may contain a hydrophilic polymer compound such as gum arabic and hydroxyethyl cellulose.

The emulsion thus prepared can be subjected to chemical sensitization (sulfur sensitization, gold sensitization, reduction sensitization, etc.) with a chemical sensitizer. However, no chemical sensitization is required.

The silver halide emulsion obtained according to the present invention can be used for general photographic purposes such as stabilizers, antifoggants, irradiation inhibitors, film physical property modifiers, surfactants, hardeners, matting agents and developing agents. Can be included.

The silver halide emulsion layer thus prepared can be coated directly on the physical development nucleus layer, but an intermediate layer of gelatin or the like may be provided for facilitating peelability. . Further, the material may have a hydrophilic colloid layer such as gelatin for protecting the surface of the photosensitive material.

The lithographic printing plate of the present invention is exposed by an ultraviolet laser light source such as a mercury lamp, an ultra-high pressure mercury lamp, a metal halide, or an ultraviolet argon laser used mainly in the printing field.
In addition, before and after the exposure, long-time safe handling under bright light can be performed.

The lithographic printing plate of the present invention is generally subjected to diffusion transfer development with an alkali developing solution after imagewise exposure to remove a residual emulsion film, and if necessary, if necessary, a neutralizing solution, a fixing solution, and a sensitizing solution. And a plate making and printing process with a humidifying liquid or the like. The developer may be an ordinary photographic alkali developer containing a developing agent such as hydroquinone, or a so-called alkaline activated developer in which the material is contained in the material and the developer is substantially free of the developing agent. Anything can be used. Some of these developing solutions are used for various purposes.
Compounds described in JP-A-1-486 and JP-A-52-150105 are added.

As the composition of the neutralizing solution, fixing solution, sensitizing solution, humidifying solution and the like used in the present invention, those having compositions known to those skilled in the art can be used according to the respective purposes.

[0037]

The present invention will be described below with reference to examples.
Of course, the present invention is not limited to this.

Example 1 An average diameter of about 5 μm was obtained by electrolytic surface roughening treatment and anodic oxidation.
0.3 mm thick having about 5,600 pits having a diameter of 0.03 to 0.30 μm per 100 μm ² on the plateau and having an average diameter of 0.08 μm for the pits
An aluminum plate (A) was obtained. This aluminum plate was anodized after the surface roughening treatment, and had an average roughness (Ra) of 0.5 to 0.6 μm.

On the pretreated aluminum support, a silver sol prepared by the Carey, Lea method was applied so that the silver amount was 10 mg / m ² .

Subsequently, silver halide was precipitated by a conventional method using 10-5 mol of a rhodium chloride salt per mol of silver chlorobromide containing 95 mol% of silver chloride, and subjected to physical ripening to obtain an average grain size. An emulsion having a diameter of 0.2 μm was obtained. This emulsion was desalted and redissolved. Then, 7 mg per mol of silver halide of pinacritol yellow was added as an organic desensitizer, and a stabilizer and a surfactant were further added.

This emulsion was coated on the aluminum support coated with silver sol and dried so that the silver content was 1.5 g / m ² and the gelatin content was 1.0 g / m ² .

The lithographic printing plate produced as described above is
After imagewise exposure using a bright room printer, diffusion transfer development was performed at 20 ° C. for 30 seconds in the following alkaline developer. Phenidone B = 4-methyl-1-phenyl-3-pyrazolidone

After the development by diffusion transfer, the emulsion layer was peeled off, whereby a lithographic printing plate on which a diffusion transfer silver image was formed was produced.

When this sample was irradiated in a bright room of about 500 lux for 1 hour and then exposed and developed in the same manner as above, there was no change in sensitivity and tone, and a lithographic printing plate having a diffusion-transferred silver image formed thereon. Could be produced. Further, when the sample was exposed to light in the above-mentioned light room for 15 minutes after being subjected to imagewise exposure and then developed similarly, there was no change in sensitivity or tone.

Example 2 In the above-mentioned Example 1, the organic desensitizers (A), (E), (O), and
Four types of lithographic printing plates were prepared in exactly the same manner except that each of (P) was added to the re-dissolved emulsion. When the suitability for the light room environment was tested in the same manner as in Example 1, a lithographic printing plate having good sensitivity and tone was obtained.

COMPARATIVE EXAMPLE The procedure of Example 1 was repeated, except that no rhodium chloride salt was added during the precipitation of the silver halide emulsion, and that 0.15 mg of pinakryptol yellow was added per mol of silver halide to the re-dissolved emulsion. A lithographic printing plate was prepared. When this sample was exposed and developed after irradiating it in a bright room of about 300 lux for 30 minutes, the diffusion transfer silver image was an extremely thin image.

Example 3 The lithographic printing plates prepared in Examples 1 and 2 were applied to a copy rapid fixer (Fixe) manufactured by Agfa.
r), after the surface treatment, the printing press Heidelberg TOK
(Heidelberg's offset printing machine trademark), printing was performed on 100,000 sheets, and the print quality was good. The sample of the comparative example was also subjected to a printing test in the same manner, but hardly covered with ink and did not function as a lithographic printing plate.

Example 4 The following Table 1 shows the difference between the electrolytic surface roughening treatment and the anodic oxidation.
An aluminum plate having a surface shape shown in FIG.

[0049]

[Table 1]

In Table 1, the number of pits is about 5 μm on average.
0.03 to 0.30 μm on the plateau of m
Are the number of pits per 100 μm ² , and the average diameter is the average value of the diameters of those pits. The average roughness (Ra) of these aluminum plates was 0.5 to 0.6 μm.

On these aluminum supports, in the same manner as in Example 1, planographic printing plates A-1, B-1, C-1, D-
1 and E-1 were produced.

The lithographic printing plate thus obtained was subjected to image exposure, developed with the diffusion transfer developer described in Example 1, and immediately washed (washed off) with a running water. Before the plate surface dries, apply a plate surface protection solution with absorbent cotton or the like and dry. The lithographic printing plate created in this way is used as a printing press Heidelberg TOK (Heidelberg
Image quality and printing durability.

Regarding the image quality, a mark that can simultaneously reproduce a negative ruled line and a positive ruled line of 10 μm on the printing plate surface exposed and developed through a contact original is indicated by a circle, and a pattern that can be simultaneously reproduced by a negative ruled line and a positive ruled line of 15 μm. The symbol Δ indicates that a negative ruled line and a positive ruled line of 20 μm can be simultaneously reproduced. The ink used is New Champion F Gloss Black N manufactured by Dainippon Ink and the printing durability is set to 5 mm. The printing pressure is set to 5 mm. Evaluation was made based on the number of printed sheets when it became impossible. Table 2 shows the results.

[0054]

[Table 2]

As is clear from the results in Table 2, the diameter 0.0
3 to 0.30 μm pits of 500 per 100 μm ²
And the average diameter of those pits is 0.0
Lithographic printing plate A using aluminum plate of 5 to 0.20 μm
-1, B-1 and C-1 were found to be excellent in image quality and printing durability. On the other hand, a lithographic printing plate D- using an aluminum plate having an average pit diameter of 0.20 μm or more.
From the results of E-1 and E-1, it can be seen that A-1, B-1, and C-1 are more preferable.

[0056]

According to the present invention, it is possible to manufacture an aluminum lithographic printing plate which can be handled in a substantially bright room environment, uses a silver complex salt diffusion transfer system, and has high image quality and high printing durability.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03F 7/07 B41N 1/08 G03F 7/09

Claims (2)

(57) [Claims] In a lithographic printing plate having a physical development nucleus layer between a roughened and anodized aluminum support and a silver halide emulsion layer, the lithographic printing plate contains 10 per mole of silver halide in the silver halide emulsion. ^-8 to 10 ^-3 mol of water-soluble rhodium
0.2 to 200 m per mole of silver salt and silver halide
A lithographic printing plate comprising g of an organic desensitizer. 2. A rough aluminum plate having at least 500 pits having a diameter of 0.03 to 0.30 μm per 100 μm ² and having an average diameter of the pits of 0.05 to 0.20 μm. The lithographic printing plate according to claim 1, wherein