JP3474371B2 - Lithographic printing plate and its processing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate utilizing an aluminum plate as a support and utilizing a silver complex salt diffusion transfer method, and a method for treating the lithographic printing plate. 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" published by Focal Press, London New York (1972), by Andrelot and Edith Weide. Some examples are described in "Halide 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. A lithographic printing plate of the monosheet type utilizing a silver complex salt diffusion transfer method using an aluminum plate as a support (hereinafter referred to as an aluminum lithographic printing plate), which is an object of the present invention, is disclosed in JP-A-57-118244. No. 57-158
Nos. 844 and 63-260491, JP-A-3-116
No. 151, 4-282295, U.S. Pat.
Nos. 7,131, 5,427,889 and the like. [0005] The aluminum lithographic printing plate has a structure in which a physical development nucleus is supported on a roughened and anodized aluminum support, and a silver halide emulsion layer is further provided thereon. The general method of making a lithographic printing plate is
After exposure, development, washing (removal of the silver halide emulsion layer), and finishing are performed. More specifically, a metal silver image portion is formed on a physical development nucleus by a development process, and a silver halide emulsion layer is removed by a subsequent washing process to form a metal silver image portion (hereinafter referred to as silver) on an aluminum support. Image portion) is exposed. At the same time, the anodized aluminum surface itself is exposed as a non-image area. The aluminum lithographic printing plate targeted by the present invention as described above has a problem that white spots often occur on the image portion of the printed matter. This is considered to be caused by corrosion of the aluminum plate as the support. JP-A-63-260491, JP-A-3-1
No. 16151 describes the cause of corrosion of an aluminum plate. It is described that the former is corroded by the presence of an electromotive force between the two metals due to the close contact between the metallic silver image and the aluminum plate, and the latter is corroded by physical development nuclei or gelatin in the silver halide emulsion layer. For preventing corrosion, JP-A-63-260491 discloses that the amount of anodic oxidation and surface roughness are specified, and JP-A-3-116151 discloses that a non-protein water-swellable intermediate layer is provided. It is also generally known to use corrosion inhibitors such as mercapto compounds. Although the white spots in the image area have been improved to some extent by the above method, they are still insufficient and further improvement is desired. On the other hand, the printing plate is generally used for printing within a short period of time (usually within one week) after the plate making process, but after printing once, the printing plate is stored (placed),
It is often used again for printing. The stencil may extend for more than one month, and the longer the stencil is, the more the corrosion of aluminum increases, which has adversely affected the printing after the stencil as described above. SUMMARY OF THE INVENTION An object of the present invention is to provide an aluminum lithographic printing plate which solves the above-mentioned problems, has no white spots on an image portion, has excellent print quality, and a processing method therefor. is there. The object of the present invention is to provide a lithographic printing plate having a physical development nucleus between an aluminum support and a silver halide emulsion layer, which contains an acetylene glycol compound. A lithographic printing plate characterized by:
2) a method of processing a lithographic printing plate, which comprises treating a lithographic printing plate having a physical development nucleus between an aluminum support and a silver halide emulsion layer with a developer containing an acetylene glycol compound; 3) aluminum After development of a lithographic printing plate having a physical development nucleus between the support and the silver halide emulsion layer, the plate is treated with a washing solution containing an acetylene glycol compound and / or a finishing solution containing an acetylene glycol compound. A lithographic printing plate processing method. In the present invention, the acetylene glycol compound is contained in the lithographic printing plate to prevent corrosion of the aluminum support during storage from the production of the lithographic printing plate to the plate making process. By treating with a developing solution containing, to prevent corrosion of the aluminum support by the alkali developing solution,
By being included in the washing liquid and / or the finishing liquid,
The purpose of the present invention is to prevent corrosion of the aluminum support by the plate after the plate making process, and to suppress the occurrence of white spots during printing. Hereinafter, the present invention will be described in detail.
Acetylene glycol is a compound having an acetylene bond (carbon-carbon triple bond) and an alcohol (ROH: R is an alkyl group) in the molecule. In particular, two carbon atoms adjacent to the alkyne triple bond have one carbon atom each. A compound having a hydroxyl group, for example, having the general formula Embedded image R ₁ , R ₂ , R ₃ and R ₄ preferably have 4 carbon atoms.
And R ₁ and R ₃ are particularly preferably methyl groups. N + m = N represents the number of moles of ethylene oxide added, and is preferably 10 or more. Specific examples of Chemical Formula 1 include Chemical Formulas 2 and 3
And shown in Chemical Formula 4. Embedded image Embedded image Embedded image The acetylene glycol used in the present invention is manufactured by Air Products and Chemicals, Inc. of the United States, and is sold by Nissin Chemical Co., Ltd. under the trade name "Surfynol". The compound represented by the above chemical formula 2 is Surfynol 82, and the compound represented by the chemical formula 3 is surfynols 104A, 104E and 104H (104A is a 50% by weight solution of 2-ethylhexyl alcohol, 104E and 1E).
04H is 50 and 75% by weight of ethylene glycol
Liquid), and the compound represented by the chemical formula 4 is Surfynol 44
0, 465, 485 (440 is N = 3, 5, 465 is 1
0 and 485 are 30). Other examples include Surfynol TG in which Surfynol 104 and polyoxyethylene alkyl phenyl ether are dissolved in ethylene glycol at a high concentration. Surfynols 82, 465 and 485 are preferred because of their relatively high solubility in water. However, the present invention is not limited to these. In the present invention, the acetylene glycol compound is contained in a physical development nucleus layer, a silver halide emulsion layer and the like constituting a lithographic printing plate. Content is 0.01-5g
/ M ² is appropriate. When it is contained in the developing solution, the washing solution and the finishing solution, the content is suitably about 0.1 to 10 g / liter. The lithographic printing plate of the present invention has a physical development nucleus and a silver halide emulsion layer on an aluminum support. The silver halide emulsion is selected from commonly used silver chloride, silver bromide, silver iodide, silver chlorobromide, silver chloroiodobromide, silver iodobromide, etc., but mainly contains silver chloride (50 mol of silver chloride). %). The emulsion type may be either a negative type or a positive type. These silver halide emulsions can be chemically or spectrally sensitized as necessary. Gelatin is preferably used as a hydrophilic colloid in the silver halide emulsion layer when preparing silver halide grains. Various gelatins such as acid-treated gelatin and alkali-treated gelatin can be used as the gelatin.
Further, those modified gelatins (for example, phthalated gelatin, amidated gelatin, etc.) can also be used. Further, hydrophilic polymer compounds such as polyvinylpyrrolidone, various starches, albumin, polyvinyl alcohol, gum arabic, and hydroxyethyl cellulose can be contained. As the hydrophilic colloid to be used, it is desirable to use a hydrophilic colloid layer substantially free of a hardener in order to facilitate the peelability after development. The aluminum support used in the present invention is a roughened and anodized aluminum plate, preferably the one described in US Pat. No. 5,427,889. The physical development nucleus of the physical development nucleus layer used in the present invention may be a physical development nucleus used in a known silver complex salt diffusion transfer method, for example, a colloid such as gold or silver, or a water-soluble salt such as palladium or zinc. Metal sulfide mixed with sulfide can be used. Various hydrophilic colloids can be used as the protective colloid. See, for example, "Photographic Silver Halide Diffusion Processes" by Andrelot and Edith Weide, Focal Press, New York, London (1972) for details. In the present invention, a water-swellable intermediate layer described in JP-A-3-116151 may be provided between the physical development nucleus layer and the silver halide emulsion layer. In the developer used in the present invention, in addition to the acetylene glycol compound, developing agents such as polyhydroxybenzenes, 3-pyrazolidinones, and alkaline substances such as potassium hydroxide, sodium hydroxide, lithium hydroxide Sodium tertiary phosphate, or amine compounds, preservatives such as sodium sulfite, thickeners such as carboxymethylcellulose, antifoggants such as potassium bromide, development modifiers such as polyoxyalkylene compounds, silver halide Solvents, for example, additives such as thiosulfate, thiocyanate, cyclic imide, thiosalicylic acid and mesoionic compounds can be included. The pH of the developer is usually from 10 to 14, preferably from 12 to 14. In the water washing solution used in the present invention, in addition to the acetylene glycol compound, a lipophilic agent for making the silver image area lipophilic, the pH of which is buffered in the range of 4 to 8, preferably 4.5 to 7. It may contain a buffer, for example a phosphate buffer, a citrate buffer or a mixture thereof. Further, a preservative may be contained. The washing solution may further contain proteolytic enzymes. A neutralization stabilization treatment for stopping the progress of the development may be performed between the development treatment and the water washing treatment. The above-mentioned washing solution is used for completely removing the silver halide emulsion layer on the aluminum support.
Usually, a method of spraying a washing liquid at 25 to 35 ° C. by a jet method or a method of peeling the emulsion layer with a scrub roller while spraying the washing liquid is adopted. In the aluminum lithographic printing plate, the washing and removal of the silver halide emulsion layer is a very important step for completely exposing the silver image portion and the non-image portion constituted by the aluminum surface itself. In particular, the silver image portion receiving the ink needs to have strong lipophilicity, and it is necessary to completely remove substances that inhibit lipophilicity such as gelatin. The silver image portion and the non-image portion exposed by the water washing process are treated with a finishing liquid in order to increase their lipophilicity and hydrophilicity and to protect the plate surface.
In the finishing solution used in the present invention, in addition to the acetylene glycol compound, for protecting the anodized layer in the non-image area and improving the hydrophilicity, gum arabic, dextrin, sodium alginate, propylene glycol ester of alginic acid, hydroxyethyl It is preferable to contain a protective colloid such as starch, carboxymethylcellulose, hydroxyethylcellulose, polyvinylpyrrolidone, polystyrenesulfonic acid, and polyvinyl alcohol. Further, a lipophilic agent for the silver image portion may be contained. EXAMPLES The present invention will be described below with reference to examples. EXAMPLE 1 Electrolytic surface roughening treatment and anodic oxidation of an aluminum support were carried out according to the method described in US Pat. No. 5,427,889 on a plateau having an average diameter of about 5 μm.
0.35 μm pits of about 5,60 per 100 μm ²
And the average diameter of these pits is 0.08
A 0.30 mm thick aluminum plate having a thickness of 0.3 μm 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 an aluminum support, Curry Lee is used.
A physical development nucleus solution composed of a silver sol prepared by the y Lea) method was applied, and then dried. The amount of silver contained in the physical development nucleus layer was 3 mg / m ² . As a silver halide emulsion, alkali-treated gelatin was used as a protective colloid, and potassium hexachloroiridate (IV) having an average particle size of 0.2 μm was added in an amount of 0.006 m per mol of silver by a control double jet method.
A mol-doped silver chloroiodobromide emulsion (AgBr 20 mol%, AgI 0.4 mol%) was prepared. Further, this emulsion was subjected to sulfur gold sensitization, and the sensitizing dye represented by the formula (5) was added in an amount of 3 to 1 g of silver.
mg was used for spectral sensitization. Embedded image A surfactant is added to the silver halide emulsion prepared in this manner, coated on an aluminum support coated with a nucleus solution so that the silver amount becomes 2 g / m ² , and dried to form a lithographic printing plate. A was obtained. <Lithographic printing plate B> A lithographic printing plate was prepared by further adding 0.5 g / m ² of Surfynol 82 as an acetylene glycol compound to the silver halide emulsion layer of the lithographic printing plate A. The lithographic printing plate was stored at 30 ° C. and 80% for 2 weeks. Immediately after production of the lithographic printing plate and after storage, the image is output by an output device using a 633 nm red LD laser as a light source, and then processed by a plate-making processor (Dupont SLT-N automatic developing machine). To make a lithographic printing plate. The plate-making processor performs the development process (21 ° C., 3
(E.g., immersion for 0 seconds), a water-washing process (the emulsion layer is peeled off by a scrub roller while spraying a water-washing solution at 33 ° C. for 10 seconds), a finishing process (21 ° C., 5-second shower), and a drying process. . Processing was carried out using the following developing solution, washing solution and finishing solution. <Developer A> sodium hydroxide 20 g hydroquinone 20 g 1-phenyl-3-pyrazolidinone 2 g anhydrous sodium sulfite 80 g monomethylethanolamine 6 g anhydrous sodium thiosulfate 6 g ethylenediaminetetraacetate sodium salt 5 g polyethylene glycol (average molecular weight 400) 10 g water To adjust the total amount to 1000 cc. pH is 1
It was adjusted to 3.0. <Developer B> To the above developer A, 2 g of Surfynol 82 was added as an acetylene glycol compound. <Washing Solution A> 40 g of first potassium phosphate water is added to adjust the total amount to 1000 cc. pH is 6.
Adjusted to zero. <Finishing liquid A> Gum arabic 10 g 2-mercapto-5-n-heptyl-oxadiazole 1 g Triethanolamine 26 g Sodium monophosphate 10 g Water is added to adjust the total amount to 1000 cc. pH is 6.
Adjusted to zero. The lithographic printing plate produced by the method described above was used for a printing press Heidelberg TOK (trademark of an offset printing press manufactured by Heidelberg), an ink (New Champion Ink H manufactured by Dainippon Ink Co., Ltd.) and a commercial PS plate. After printing 100 sheets using the moisturizer, the ink was removed from the printing plate surface with an ink remover, and the number of corrosion spots on the plate surface that caused white spots on the printed matter was counted and evaluated according to the following criteria. Table 1 shows the results. Evaluation criteria for corrosion spots on the printing plate Grade 1: Almost no occurrence. Grade 2: Several occurrences. Grade 3: Dozens occurred. Grade 4: 50 or more occurred. [Table 1] From the above results, it can be seen that the inclusion of the acetylene glycol compound in the lithographic printing plate markedly suppresses the corrosion of the aluminum support due to storage time after production. Further, it can be seen that by adding an acetylene glycol compound to the developer, corrosion due to alkali is suppressed. Example 2 A test was carried out in the same manner as in Example 1 except that the acetylene glycol compound was changed from Surfynol 82 to Surfynol 465 and 485. The same results as in Example 1 were obtained. Example 3 Washing solution B and finishing solution B were prepared by adding 2 g of Surfynol 82 to washing solution A and finishing solution A of Example 1, respectively. After treating the lithographic printing plate B of Example 1 with the developer B,
The washing liquid and the finishing liquid were treated in the combinations shown in Table 2, and the state of corrosion immediately after the treatment and after one month of storage was evaluated in accordance with Example 1. Table 2 shows the results. [Table 2] From the above results, it can be seen that the corrosion caused by the plate after the plate making process can be prevented by adding an acetylene glycol compound to the washing liquid or the finishing liquid. According to the present invention, the aluminum lithographic printing plate using a silver complex salt diffusion transfer method contains an acetylene glycol compound, whereby the aluminum support can be prevented from corroding due to storage time after production. In addition, by containing it in a developer, corrosion during development can be suppressed. Further, by including the rinsing liquid and / or the finishing liquid in the rinsing liquid, it is possible to prevent corrosion caused by the stencil after plate making.

Claims (1)

(1) A lithographic printing plate having a physical development nucleus between an aluminum support and a silver halide emulsion layer, wherein the lithographic printing plate contains an acetylene glycol compound. .