JPH06258839A - Method for processing planographic printing plate - Google Patents

Abstract

PURPOSE:To provide the processing method for the direct planographic printing plate improved in omission of transferred silver image, remarkably enhanced in printing resistance, and freed from drop of ink receptivity. CONSTITUTION:The planographic printing plate is formed by using the silver complex salt diffusion transfer method and processing in the presence of at least one kind of compounds represented by the formula in which each of R<1> and R<2> is H, an alkyl, or alkoxy; each of Z<1> and Z2 is a monovalent metal ion or H or an acyl; X is a divalent group having O and N atoms and forming 15-, 18-, or 21-membered ring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a lithographic printing plate by a silver complex salt diffusion transfer method.

[0002]

2. Description of the Related Art An offset printing plate using a silver image obtained by a silver complex salt diffusion transfer method (DTR) has already been disclosed in Japanese Patent Publication No. 46-43132 or Japanese Patent Publication No. 48-3.
No. 0562, and a positive type printing original plate is disclosed in Japanese Patent Laid-Open Publication No. 49-55402.
Regarding negative type printing original plates, published patent publication Sho 52-
No. 106902, JP-A No. 52-112402, and the like.

These direct printing plates are composed of a support, an undercoat layer also serving as an antihalation layer, a silver halide photographic emulsion layer and a physical development nucleus layer on the support. When a light-sensitive material is imagewise exposed and then treated with a developer containing a developer and a silver halide solvent, the silver halide on which a latent image is formed becomes blackened in the emulsion layer. The silver halide in which the silver halide is not formed is dissolved by the action of the silver halide complexing agent and diffuses to the surface of the light-sensitive material. This silver complex salt is deposited as a silver image on the physical development nuclei of the surface layer by the reducing action of the developing agent. This process results in a direct printing plate.

In order to enhance the ink receptivity of the silver image, after development, an oil-sensitizing treatment is carried out if necessary, and the ink image is transferred to a printed matter by an offset printing machine. This direct printing plate has advantages such as good operability and low price, but on the other hand, due to the nature of forming a silver image for printing by photographic development processing, diffusion transfer is completed within the processing time. However, excessive silver ions remained, which contributed to a decrease in storage stability or printing durability.

Various methods are utilized to remedy these drawbacks. One of them is a method of using various appropriate compounds as a silver halide complexing agent. JP-A-56
Nos. -1057 and 56-9750 describe a method of adding thiosalicylic acid and a substituted derivative thereof to a processing liquid or a constituent layer of a printing plate. Ibid 56-62
Nos. 37 and 56-8145 describe a method in which thiosalicylic acid and its derivative are used in combination with an alkanolamine or a cyclic imide compound, but there are drawbacks such as reduction of ink sticking of silver images, and further improvement is desired.

Further, Japanese Patent Laid-Open No. 62-239161 describes a method in which a benzotriazole compound is used as a development inhibitor and the printing durability is improved by controlling the DTR. Although the printing durability is improved to some extent by this method, the amount of ink sticking is reduced and it has not yet reached a sufficient level. In particular, there is a need for a method that does not reduce ink sticking.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to obtain a silver image having a good printing durability and a high ink acceptability in the development processing of a direct lithographic printing plate utilizing the silver complex salt diffusion transfer method. Is to provide a processing method.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventor has conducted development and stabilization in the presence of a development inhibitor having a chelating function in the same molecule. It was found that the object of the present invention can be achieved by the above.

That is, the present invention is a method of treating a silver salt diffusion transfer lithographic printing plate in the presence of a compound represented by the following chemical formula 2.

[0010]

[Chemical 2]

In Formula 2, R ¹ and R ² may be the same or different and each represents a hydrogen atom, an alkyl group or an alkoxy group, and Z ¹ and Z ² may be the same or different and are monovalent metal ions. , A hydrogen atom or an acyl group, X is a divalent group containing an oxygen atom or a nitrogen atom,
Form a 15, 18 or 21 membered ring. Specific examples of the compound of Chemical formula 2 used in the present invention are shown below.

[0012]

[Chemical 3]

[0013]

[Chemical 4]

[0014]

[Chemical 5]

[0015]

[Chemical 6]

[0016]

[Chemical 7]

[0017]

[Chemical 8]

[0018]

[Chemical 9]

[0019]

[Chemical 10]

[0020]

[Chemical 11]

The compound of the present invention was synthesized by formylating the mother benzocrown ether by the Vilsmeier reaction, followed by nitration, and the formyl group was oxidized with KMnO4 to reduce the nitrobenzoic oxygen derivative with Fe to obtain anthranilic acid. Obtain the derivative. This amino compound was diazotized, reacted with potassium xanthate, and then reduced with sodium hydrosulfite to synthesize. The benzocrown ether, which is the mother nucleus, is, for example, Synthesis 680.
(1986), tetrahedron. Letters (Tetrahedron Lett.)
26 2705 (1985), Chemical Communication (Chem.com
mun) 268 (1986), Journal of Polymer Science (J. Polymer Sci. A- 19 817 (1971), Journal of American Chemical Society (J. Amer. Chm. So)
c.) 95 , 3842 (1973) Chemical Communication (Che
m.commun) 414 (1975), 639 (1976), 640 (1976). In addition, the formylation of benzocrown ether is based on the Journal of Chemical Society (JC
S. Dalton) p. 1696 (1978). The synthesis examples of representative compounds of the present invention are shown below.

Synthetic Example (Synthesis of Chemical Formula 3) Journal of Chemical Society (JCS Dalton)
Benzo-1 synthesized by the method of page 1696 (1978)
10 g of 5-crown-5-4-aldehyde was dissolved in 70 ml of chloroform, and the outside was cooled with a dry ice-methanol bath, and the fuming nitric acid (SG =
1.50) 10 ml was added dropwise. Then, the mixture was stirred at room temperature for 4 hours. The reaction solution was poured into water and extracted with chloroform. The chloroform layer was washed with water, dried and evaporated under reduced pressure to obtain 10 g of a crude nitro compound as a yellow solid. PMR (CDCL ₃ )
δ, 10.43 (1H.S.-C HO ), 7.58 (1
H, S, 6th), 7.37 (1H, S, 3rd), 4.2
0-4.29 (4H, m), 3.89-3.99 (4
H, m), 3.70-3.79 (8H, m)

10 g of the crude nitroaldehyde compound was finely crushed, 60 ml of water was added, and 7.8 ml of 35% NaOH was added.
Add and suspend. The mixture was heated to an internal temperature of 70 ° C., 10 g of potassium permanganate was dissolved in 60 ml of water while stirring well, and the mixture was added dropwise at an internal temperature of 73-80 ° C. (Time required 2 hours)
After reacting at the same temperature for 4 hours, the mixture was allowed to cool, the insoluble matter was filtered off, and the filtrate was acidified with concentrated hydrochloric acid. The precipitated crystals were collected by filtration, washed with water and dried.

7.9 g (yellow solid) mp109-111
° C PMR (DMSO) δ 7.53 (1H, S)
7.26 (1H, S), 4.21-4.18 (4H,
m), 3.79-3.73 (4H, m), 3.62 (8)
H, S), CMR (DMSO / NaOH), δ166.
6, 151.5, 150.0, 141.9, 121.
8, 121.8, 108.8, 70.4, 69.4, 6
9.1, 68.1

Next, 15 g of iron powder, 15 ml of water and 3 of dioxane.
2 ml of acetic acid was added to 0 ml of the mixture with heating and stirred for 15 minutes,
7.1 g of crude nitro compound is dissolved in 50 ml of dioxane and added dropwise. (10 minutes required) After cooling under reflux for 1 hour, the reaction product was filtered through Celite 520A. Dioxane in the filtrate was distilled off under reduced pressure to obtain 5.3 g of a crude amino compound.

5.2 g of this amino compound was added to 0.98 g of potassium hydroxide and 1.22 g of sodium nitrite together with 30 parts of water.
Dissolve it in ml and add it dropwise to a mixture of concentrated hydrochloric acid (12 ml) and water (16 ml) kept at an internal temperature of 0-5 ° C (time required: 20 minutes).
After stirring for 0 minutes, 4.4 g of potassium acetate was added to adjust the pH to 5 or less, and the diazonium salt was added dropwise to a solution of 7.28 g of potassium ethylxanthate dissolved in 30 ml of water at an internal temperature of 35 ° C. (required time: 10 minutes). After stirring for 1 hour (room temperature), the mixture was acidified with concentrated hydrochloric acid, and the crystallized product was washed with water and dried to give 1 crystal.
Dissolve in 50 ml of 0% sodium carbonate, add 5.6 g of sodium hydrosulfite while refluxing, and reflux for 1 hour. The reaction product was acidified with concentrated hydrochloric acid under cooling, the precipitated crystals were washed with water, dried and then separated by column chromatography with a mixed solvent of chloroform: methanol = 1: 1. The desired fraction was concentrated to give pale yellow crystals.

Yield 3.1 g mp 240-242 ° C. PMR (DMSO-d ₆ ) δ7.19 = (1H,
S), 7.61 (1H, S), 4.34 to 4.30 (4
H, m), 4.04 to 3.95 (4H, m), 3.90.
~3.85 (8H, m), CMR (DMSO-d 6),
δ170.4, 157.9, 148.0, 133.3,
120.4, 114.1, 99.5, 69.8, 68.
6, 67.6, 66.4

The amount of the compound of formula 2 of the present invention added to the developing solution is in the range of 10 ^-5 to 10 ^-1 mol / l, preferably 10 ^-3 to 10 ^-2 mol / l. Further, two or more kinds of compounds can be used in combination.

The compound of the present invention is most effectively added to a developing solution, but a processing solution such as a stabilizing solution, a silver halide emulsion layer or a physical development nucleus layer of a direct printing plate, preferably a silver halide. It may be added to the emulsion layer. In that case, the addition amount is in the range of 10 ⁻⁷ to 10 ⁻³ mol / m ² , and preferably 10 ⁻⁶ to 10 ⁻⁴ mol / m ² . Further, two or more kinds of compounds can be used in combination. The addition to the treatment liquid is preferably carried out by dissolving in an organic solvent. The same applies when it is added to the emulsion.

The developing solution of the present invention contains an alkaline substance (sodium hydroxide, potassium hydroxide, sodium triphosphate, etc.) and a sulfite salt (potassium sulfite, as a preservative).
Sodium sulfite, etc.) is essential, but other compounds such as sulfates (sodium sulfate, ammonium sulfate, etc.), antifoggants (potassium bromide, etc.), silver halide solvents (thiosulfates, thiocyanates, thioethers) , Cyclic imide, thiosalicylic acid, alkanolamine, etc.), developing agent (hydroquinone, 1-phenyl-3)
-Pyrazolidone, methol, etc.) and development accelerators (polyoxyalkylene compounds, onium compounds, etc.).

Further, one or more kinds of surfactants (propylene glycol alginate, etc.), aminopolycarboxylic acid salts (sodium ethylenediaminetetraacetate, etc.) can be contained. In addition to these, a solvent for the compound of the present invention, for example, a water-miscible organic solvent such as methanol, ethanol, propanol, isopropyl alcohol, n-butyl alcohol, DMF, dioxane and the like can be included.

In carrying out the silver complex salt diffusion transfer method, for example, British Patent Nos. 1000115 and 1012476.
No. 1017273, 1042477, the incorporation of a developing agent into the silver halide emulsion and / or the image receiving layer or other water permeable layer adjacent thereto has been carried out. There is. Therefore, in such a light-sensitive material, the processing solution used for development may be a simple alkaline solution containing no developing agent. The compound of the present invention is also effective in such a type of sensitive material.

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

The binder used in the silver halide emulsion of the lithographic printing plate of the present invention is usually gelatin, but a part of gelatin is starch, albumin, sodium alginate, hydroxyethyl cellulose (HEC), natural gums such as gum arabic and the like. Polymer, polyvinyl alcohol (P
VA), polyvinylpyrrolidone (PVP), carboxymethyl cellulose (CMC), polyacrylamide, styrene-maleic anhydride copolymer and the like may be substituted with one or more synthetic polymers.

An undercoat layer may be included on the lower side (support surface) of the silver halide emulsion layer for the purpose of improving adhesion and / or preventing halation. This layer may contain a developing agent and a matting agent. I can.

The support on which the silver halide emulsion is coated is
Paper, various films, plastics, paper coated with resin-like substances, metal plates, etc. can be used.

The physical development nuclei used in the physical development nuclei layer are
Well-known drugs such as antimony, cadmium, cobalt,
Metals such as palladium, nickel, silver, lead and zinc and their sulfides can be used. The physical development nucleus layer may also contain a developing agent and may contain a hydrophilic binder.

[0038]

The present invention will be described in more detail with reference to the following examples, but the invention is not limited thereto.

An undercoating-treated polyester film support is provided on one side with a matting layer containing silica particles having an average particle size of 5 μ, and on the opposite side, carbon black is included to reduce the light reflectance. An anti-halation subbing layer (adjusted to pH 4.0) containing silica powder having a diameter of 7μ at a ratio of 20% by weight with respect to photographic gelatin, and a silica powder having an average particle diameter of 7μ after chemically sensitized was used as photographic gelatin. And a spectrally sensitized high-sensitivity silver chloride emulsion layer (adjusted to pH 4.0) were provided. The subbing layer was made of gelatin at 3.5 g / m ² , and the emulsion layer was made of gelatin.
8 g / m ² and silver halide (converted to silver nitrate) 1.0 g /
It was applied at a rate of m ² . The subbing layer and the emulsion layer contain formalin as a hardener at a ratio of 5.0 mg / g with respect to gelatin.

After drying, the mixture was heated at 40 ° C. for 14 days, then the emulsion was coated with the nuclear liquid described in Plate No. 31 used in Example 2 of JP-A-54-103104 and dried. , Produce lithographic printing plates. The silver halide emulsion was prepared by adding 4 × 10 ⁻⁶ mol of rhodium chloride per mol of silver halide during physical ripening, and had an average grain size of 0.40 μm.
Met. The lithographic printing plate precursor thus obtained was image-exposed with a plate-making camera having an image reversal mechanism, developed with the following developer (use solution) at 30 ° C. for 30 seconds, and then with the following neutralizing solution. Processed.

Developer A Sodium hydroxide 24 g Potassium hydroxide 8 g Anhydrous sodium sulfite 50 g 2-Methyl-amino-1-propanol 30 g Uracil 0.2 g Water is added to make 1 liter.

Neutralizing solution Ethylene glycol 5 g Colloidal silica (20% aqueous solution) 1 g Citric acid 10 g Sodium citrate 35 g Water is added to make 1 liter.

On the other hand, in addition to the developer A, the following comparative compounds 12 and 13 or the exemplified compounds of the present invention were added at a ratio of 2 × 10 ^-3 mol per liter of the developer, and the developer B was added.
~ I was prepared.

[0044]

[Chemical 12]

[0045]

[Chemical 13]

The development was carried out in the same manner as the developer A, and a plate-making process was carried out. Then, the printing plate was set in an offset printing machine, the plate surface was sufficiently wetted with an etchant having the following composition, and printing was performed using a dampening liquid having the following composition.

Etching solution Water 600 ml Isopropanol 400 ml Ethylene glycol 50 g

Humidifying liquid Water 8 l Succinic acid 6 g Sodium sulfate 25 g Ethylene glycol 100 g Colloidal silica (20% aqueous solution) 28 g

The printing results of the examples judged according to the following criteria are shown in Table 1. The printing durability of printing was determined by the following method. Printing was continued from 1,000 sheets to 50,000 sheets, and the following four levels were evaluated according to the number of printed sheets when ink bleeding occurred in the silver image area. A 50,000 or more B 25,000 or more C 10,000 or more D 5,000 or more

[0050]

[Table 1]

As is clear from Table 1, the lithographic printing plate obtained by adding the compound of Chemical formula 2 produced a silver image with dramatically excellent printing durability and satisfactorily reproduced fine line portions of the original. Moreover, it was able to withstand long printing without mechanical abrasion due to printing of the fine line portion.

[0052]

EFFECTS OF THE INVENTION The planographic printing plate produced by the processing method of the present invention is improved in the lack of transferred silver image, the printing durability is remarkably improved, and the ink receiving ability is not deteriorated.

Claims (1)

[Claims] 1. A method of treating a lithographic printing plate utilizing a silver complex salt diffusion transfer method under conditions in which at least one compound represented by the following chemical formula 1 is present. [Chemical 1] (In the formula, R ¹ and R ² each represent a hydrogen atom, an alkyl group or an alkoxy group, Z ¹ and Z ² may be the same or different and are a monovalent metal ion, a hydrogen atom or an acyl group, and X 1 Is a divalent group containing an oxygen atom or a nitrogen atom and forms a 15, 18 or 21-membered ring.)