JPH04295849A - Developer for planographic printing plate - Google Patents

Abstract

PURPOSE:To improve plate wear and to obtain silver images having high ink acceptability by incorporating a specific compd. and an org. development inhibitor without contg. mercapto groups into the above developer. CONSTITUTION:The physical development accelerator expressed by formula I and the org. development inhibitor without having the mercapto groups are used in combination in the development processing liquid in the development of a direct planographic printing plate for which a silver complex salt diffusion transfer method is utilized. In the formula I, R denotes an alkyl group, allyl group, aralkyl group, hydroxyalkyl group; X denotes a hetero atom of Se, S, O, N or is a methylene group, alkyl substd. methylene group; Z denotes the atom group necessary for forming a 5-membered ring or 6-membered ring. The compd. expressed by the formula I can be easily synthesized and the amt. of this compd. to be added to the developer is preferably in a 0.01 to 10.0wt.% range, more preferably in a 0.01 to 4.0wt.% range. Benzotriazole or benzimidazole and its deriv. are particularly effective as the org. development inhibitor which has no mercapto groups and is to be used in combination.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer used for lithographic printing plates produced by silver complex diffusion transfer.

0002

[Prior Art] An offset printing plate using a silver image obtained by the silver complex diffusion transfer method (DTR) has already been disclosed in Patent Publication No. 46-43132 or Patent Publication No. 48-3.
0562, and the positive type printing original plate is described in Published Patent Publication No. 1983-55402.
Regarding negative type printing plates, see the published patent publication 1972-
It is described in detail in No. 106902, Japanese Patent Publication No. 112402/1980, and the like.

These direct printing plates consist of a support, and thereon a subbing layer for antihalation, a silver halide emulsion layer, and a physical development nucleus layer. When a photosensitive material is imagewise exposed and then treated with a developer containing a developer and a silver halide solvent, the silver halide forming a latent image becomes blackened silver in the emulsion layer; The unformed silver halide is dissolved by the action of the silver halide complexing agent and diffused onto the surface of the photosensitive material. A printing plate is obtained by a process in which this silver complex salt is deposited as a silver image on the physical development nuclei of the surface layer by the reducing action of a developing agent. In order to enhance the ink receptivity of this silver image, after development, if necessary, a sensitizing treatment is applied and the ink image is transferred to a printed product on an offset printing press. This direct printing plate has advantages such as good operability and low price, but on the other hand, because the silver image for printing is formed by photo development processing, the diffusion transfer cannot be completed within the processing time, resulting in However, excessive silver ions remained, which was one of the causes of decreased storage stability or printing durability.

Various methods are available to remedy these shortcomings. One of them is the use of oxidizing agents. JP-A No. 55-98753 describes the use of a sulfur-containing organic compound and an oxidizing agent in combination, and JP-A No. 51-589
No. 52 and No. 61-223740 describe a method for improving printing durability using iodine ions and an oxidizing agent. Additionally, removing excess silver ions by using a chelate resin was also effective in increasing printing durability. However, a drawback of these methods was that they often tended to reduce the ink receptivity of the silver image. In addition, JP-A-57
No. 211148 and No. 58-156936 describe methods of using thione compounds as physical development accelerators. Although these methods are superior to the above methods in terms of ink adhesion and printing durability, they may cause disadvantageous changes in photographic properties, such as softening of the tone, resulting in a decrease in printing durability. there were.

[0005]

[Problems to be Solved by the Invention] An object of the present invention is to provide a processing solution for obtaining a silver image with good printing durability and high ink receptivity in the development of a direct lithographic printing plate using the silver complex diffusion transfer method. The goal is to provide the following.

[0006]

[Means for Solving the Problems] An object of the present invention is to use at least one physical development accelerator represented by the formula 2 and an organic development inhibitor having no mercapto group in the development processing solution. It was achieved by this.

[0007]

[Case 2]

In the formula, R represents an alkyl group, an allyl group, an aralkyl group, or a hydroxyalkyl group, and X represents Se, S,
It is a hetero atom of O or N, a methylene group, or an alkyl-substituted methylene group, and Z represents the remaining atomic group necessary to form a 5-membered ring or a 6-membered ring.

Typical examples of the compound of formula 2 used in the present invention are shown below.

0010

[Chemical formula 3]

[0011]

[C4]

0012

[C5]

[0013]

[C6]

[0014]

[C7]

[0015]

[Chemical formula 8]

[0016]

[Chemical formula 9]

[0017]

[Chemical formula 10]

[0018]

[Chemical formula 11]

[0019]

[Chemical formula 12]

[0020]

[Chemical formula 13]

[0021]

[Chemical formula 14]

[0022]

[Chemical formula 15]

[0023]

[Chemical formula 16]

[0024]

[Chemical formula 17]

[0025]

[Chemical formula 18]

[0026]

[Chemical formula 19]

[0027]

[C20]

[0028]

[C21]

[0029]

[C22]

These compounds are described, for example, in Journal of Organic Chemistry, Vol. 36, p. 637 (
1971) [J. Org. Chem. 36 637
(1971)], Synthesis p. 807 (1984) [Synthesis 807 (1971)], Synthesis p. 96 (1983) [Synthesis
96 (1971)], Chemical Pharmaceutical Bulletin Vol. 31, p. 1733 (1983) [C
hem・Pharm・Bull 31 1733 (
1983)], Organic Synthes Vol. 7, 1
Page 95 [Organic Synthesis, Col.
l. vol. 7 195 (1990)] and JP-A-62-246558. The amount of the compound of chemical formula 2 of the present invention added to the developer is in the range of 0.01 to 10.0% by weight, particularly preferably in the range of 0.01 to 4.0% by weight, and can be used alone or Two or more types of compounds can also be used in combination.

[0031] The organic development inhibitor having no mercapto group used in the processing solution of the present invention may be used alone or in combination of two or more, and any compound having no mercapto group may be used, but benzotriazole or Benzimidazole and its derivatives were particularly effective. The organic development inhibitor used in the present invention is a compound having no mercapto group, and typical examples are shown below.

[0032]

[C23]

[0033]

[C24]

[0034]

[C25]

[0035]

[C26]

[0036]

[C27]

The amount of the organic development inhibitor added to the processing solution is preferably 0.01 to 2.0% by weight, and the ratio with chemical formula 2 is preferably 0.01 to 1.0% by weight. preferable.

It is known that water-soluble polymers such as carboxymethyl cellulose (CMC) and hydroxyethyl cellulose (HEC) are used as thickening agents in diffusion transfer developers for lithographic printing plates (for example, in Japanese Patent Application Laid-Open No. 76603/1983).
Although they may be added to the processing solution of the present invention, these polymer compounds do not have the effect of improving printing durability.

The developing solution of the present invention contains an alkaline substance,
For example, sodium hydroxide, potassium hydroxide, sodium triphosphate, etc. and sulfites as preservatives (potassium sulfite, sodium sulfite, etc.) are essential, but other compounds such as sulfates (sodium sulfate, ammonium sulfate, etc.) are essential. ), antifoggants such as potassium bromide, silver halide solvents such as thiosulfates, thiocyanates, thioethers, cyclic imides, thiosalicylic acid, alkanolamines, etc., thickening agents such as hydroxyethyl cellulose
(HEC), carboxymethyl cellulose (CMC)
etc., developing agents such as hydroquinone, 1-phenyl-
3-pyrazolidone, methol, etc., development modifiers such as polyoxyalkylene compounds, onium compounds, etc. can be included. Furthermore, surfactants such as alginate propylene glycol ester, aminopolycarboxylic acid salts (
It is also possible to contain one or more types such as sodium ethylenediaminetetraacetate). In addition, there are other solvents for the compounds of the present invention, such as methanol, ethanol, propanol, isopropyl alcohol, n-butyl alcohol,
Water-miscible organic solvents such as dimethyl formaldehyde and dioxane can be included.

In carrying out the complex salt diffusion transfer method, for example, British Patent Nos. 1,000,115 and 1,012,47
No. 6, No. 1,017,273, No. 1,042,477
It has been practiced to incorporate developing agents into the silver halide emulsion layer and/or into the image-receiving layer or other water-permeable layers adjacent thereto. Therefore, in such a photosensitive material, a so-called "alkaline activating solution" which does not contain a developing agent may be used as a processing solution for development. The processing liquid of the present invention is also effective for these types of photosensitive materials.

The silver halide emulsion of the lithographic printing plate used in carrying out the present invention may be silver chloride, silver bromide, silver chlorobromide, silver chloroiodide, or silver chlorobromoiodide, and silver chloride is preferable. is 50 mol% or more of silver halide. These silver halide emulsions contain spectral sensitizers (spectral sensitizing dyes depending on the light source and application, such as camera type, laser light type, panchromatic type for color separation, etc.), gelatin hardeners, coating aids, and antifoggants. , a plasticizer, a developing agent, a matting agent, etc.

The binder used in the silver halide emulsion of the lithographic printing plate of the present invention is usually gelatin, and gelatin is partially composed of starch, albumin, sodium alginate, hydroxyethyl cellulose (HEC),
Hydrophilic polymer bonds such as gum arabic, polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), carboxymethylcellulose (CMC), polyacrylamide, styrene-maleic anhydride copolymer, polyvinyl methyl ether-maleic anhydride copolymer, etc. It can also be replaced with one or more agents. Furthermore, a vinyl copolymer aqueous dispersion (latex) can also be used.

The underside (support side) of the silver halide emulsion layer may contain an undercoat layer for the purpose of improving adhesion and/or preventing halation, and this layer may contain a developing agent, a matting agent, etc. can be included.

As the support to which the silver halide emulsion is coated, paper, various films, plastics, paper coated with a resin-like substance, metal plate, etc. can be used.

The physical development nuclei used in the physical development nucleus layer are:
Chemicals of this type are well known and can include metals such as antimony, cadmium, cobalt, palladium, nickel, silver, lead, zinc, and their sulfides. This physical development nucleus layer may also contain a developing agent or a hydrophilic binder.

[0046]

[Examples] The present invention will be specifically explained below using examples, but it is of course not limited thereto.

Example 1 A matting layer containing silica particles with an average particle size of 5 μm was provided on one side of a subbed-treated polyester film support, and an amount of carbon was applied on the opposite side to give a light reflectance of 3% at 633 nm. Contains black, 20% for photographic gelatin
An antihalation subbing layer (adjusted to pH 4.0) containing silica powder with an average particle size of 7 μm in weight% and 5% by weight of silica powder with an average particle size of 7 μm on photographic gelatin after being chemically sensitized. A spectrally sensitized high-sensitivity silver chloride emulsion (adjusted to pH 4.0) was prepared. Gelatin in the undercoat layer is 3.5g/m2, and gelatin in the emulsion layer is 0.8g.
/m2, silver halide converted to silver nitrate 1.0g/m2
It was applied at a ratio of 2. The undercoat layer and emulsion layer contained formalin as a hardening agent in an amount of 5.0 mg/g based on gelatin. After drying and heating at 40°C for 14 days,
On this emulsion layer, JP-A-54-103104 Example 2
Plate No. A lithographic printing plate is produced by applying the nuclear solution described in 31 and drying it. The silver halide emulsion had 4 x 10-6 mol of rhodium chloride added per mol of silver halide during physical ripening, and had an average grain size of 0.40 microns. The lithographic printing plate master obtained in this manner was image-exposed using a plate-making camera having an image reversal mechanism, and developed with the following developer A (working solution) at 30°C for 30 seconds, followed by the following neutralizing solution. Processed with.

Developer solution A Sodium hydroxide

24g potassium hydroxide

8g anhydrous sodium sulfite

50g 2-methyl-2-amino-1-
Propanol 30g
Uracil

Add 0.2g water to make 1L.

Neutralizing liquid ethylene glycol

5g colloidal silica (20% aqueous solution)
1g
citric acid

10g sodium citrate

Add 35g water to make 1L.

On the other hand, as a comparison of the above developer A, a developer B- was prepared by adding Exemplified Compound 3 of the present invention and an organic development inhibitor.
H was prepared. However, as a comparative example, developer C used the following chemical compound 28, which is a typical compound that is a mercapto group-containing inhibitor. Development was carried out in exactly the same manner as developer A described above. The printing plate was then set in an offset printing machine, the plate surface was sufficiently moistened with an etchant having the composition shown below, and printing was carried out using a dampening liquid having the composition shown below.

Etch liquid water

600ml isopropanol

400ml ethylene glycol

50g

Moisturizing liquid water

8l succinic acid

6g sodium sulfate
25g
ethylene glycol
100g
Colloidal silica (20% aqueous solution)
28g

[0053]
The printing machine was an A.B. Dick 350CD (A.B.D.
An offset printing machine (trademark) manufactured by IKE Co., Ltd. was used. The printing plate obtained with developer A showed partial loss of the transferred silver image by 5,000 sheets, and the printing plate obtained with developer B showed partial loss of the transferred silver image by 10,000 sheets. The printing plates obtained using the developing solutions D and E of the invention did not cause any loss of the transferred silver image even after 25,000 sheets were printed, and the printing plates obtained using the developing solutions F to H did not cause any loss even after 50,000 sheets were printed.

[0054]

[Table 1]

Table 1 shows the results of combining Compound 3 used in Example 1 and organic inhibitor 23 (addition amount 0.19 g/l) having no mercapto group, and shows the printing results judged according to the following criteria. Ta. The printing durability of printing was evaluated on the following four levels based on the number of printed sheets when ink splattered in the silver image area after continuous printing of 1,000 to 50,000 sheets. A 50,000 or more B 25,000 C 10,000 D 5,000

Example 2 In place of organic inhibitor 23 (addition amount 0.19 g/l) and compound 3 used in developer D of Example 1, compounds 4 to 22 were used.
The plate-making process was carried out in exactly the same manner as the developer A described above, except that 0.5 g/l of each was added and developers 1 to 19 were prepared. The printing results are shown in Tables 2 and 3. All had better printing durability than developer A.

[0057]

[Table 2]

[0058]

[Table 3]

As is clear from Tables 2 and 3, the lithographic printing plate obtained by using the compound of Chemical Formula 2 in combination with an organic development inhibitor that does not contain a mercapto group has an image with dramatically excellent printing durability. Compared to lithographic printing plates obtained using silver and organic development inhibitors containing mercapto groups, fine line areas of originals can be reproduced better, and there is no mechanical abrasion caused by printing on the fine line areas, and long printing is possible. It was durable.

[0060] The lithographic printing plate made with the developer of the present invention has improved loss of transferred silver images, dramatically improves printing durability, and has no deterioration in ink receptivity.

[C28]

Claims (1)

[Claims] Claim 1: A developer for a lithographic printing plate using a silver complex diffusion transfer method, comprising at least one compound represented by the following formula and at least one organic development inhibitor not containing a mercapto group. A developer for a lithographic printing plate characterized by containing: [Formula 1] In the formula, R represents an alkyl group, an allyl group, an aralkyl group, or a hydroxyalkyl group; The remaining atomic groups necessary to form a 5-membered ring or a 6-membered ring are shown.