JP2003295446A - Processing method for planographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a processing method for a planographic printing plate capable of always achieving high ink acceptability and high printing resistance independently of difference in sensitization temperature and time with respect to a method for developing a printing plate in which a photographically formed silver halide image is applied as lipophilicity and ink acceptability. <P>SOLUTION: In a method for making a planographic printing plate in which a photographic material having a silver halide emulsion layer is exposed and developed and an undeveloped silver halide image region is selectively made lipophilic and ink-acceptable, the photographic material is processed after the development with a processing solution comprising an organic compound having at least one propyleneoxy group per molecule, an organic compound having a mercapto group and a silver halide solvent, wherein the molar ratio of the organic compound having a mercapto group to the silver halide solvent is 1:1 to 1:8. <P>COPYRIGHT: (C)2004,JPO

Description

Description: TECHNICAL FIELD The present invention relates to a silver halide emulsion.
Exposure and development of photographic materials
The undeveloped silver halide image area is selectively lipophilic
Pertaining to the method of processing lithographic printing plates to make them acceptable
is there. [0002] Lithographic printing accepts oily inks.
Lipophilic part and hydrophilic part that does not accept ink
The lipophilic portion is colored by supplying both water and ink to the plate
The hydrophilic part selectively receives water,
By transferring the above ink to a substrate such as paper,
Have been. Therefore, to obtain good printed matter,
The difference between lipophilicity and hydrophilicity is sufficiently large,
When applied, the lipophilic part receives a sufficient amount of ink
The hydrophilic part must not accept ink at all.
is there. [0003] High sensitivity and spectral sensitization
Photographic materials consisting of silver halide emulsions
Suitable and already several methods are known. Photo gelatin
Lithographic printing plate using silver halide emulsion
Broadly speaking, the following methods are known. (1) A method using tanning development,
Tanning hydrophilic gelatin and silver halide emulsion
Develops and hardens the gelatin in the developing section to make it lipophilic,
Reasoning method (US Pat. No. 3,146,104). (2) Formed by applying a silver salt diffusion transfer method
Lipophilic surface silver metal pattern used as ink acceptability
Printing plate (US Pat. No. 3,721,559;
3,490,905, JP-B-48-30562,
J. Photo. Sci, 8, 26-32 (1960)
A. Rott & L. (3) Development by applying etching bleach
Silver image part or silver image formed by transfer development
Area with bleaching solution, and at the same time break the gelatin in the silver image area.
Lithographic printing plate by breaking and exposing the lipophilic surface
How to create. (U.S. Pat. No. 3,385,701;
No. 3,814,603, JP-B-44-27242
(4) Undeveloped halo in silver halide emulsion layer
Method for selectively accepting a silver genide image portion as an oleophilic ink
(U.S. Pat. Nos. 3,454,398 and 3,764,3
No. 23, No. 3,099, 209, JP-B-57-393
9, JP-B-61-23545, JP-A-4-1235
No. 3, JP-A-9-304934, JP-A-9-3049
No. 35). The lithographic printing plate of the present invention meets the above classification (4).
Belong. Use of undeveloped silver halide image as lipophilicity
As a lithographic printing plate, for example, thiol compound
A method of treating with a lukari solution (US Pat. No. 3,099,20)
No. 9), a terminal ethynyl compound (US Pat. No. 3,454,
398) or a benzotriazole compound (US Patent
No. 3,764,323).
Methods have been proposed. On the other hand, silver halide solvent and silver ions react with
Treatment solution containing an organic compound that forms a poorly soluble compound in response
(Hereinafter referred to as lipophilization solution) is proposed.
It has been proposed (Japanese Patent Publication No. 57-3939). Here halo
Silver halide solvents act on silver halide,
A compound that can form a complex with high solubility
Thiosulfates, thiocyanates, thioureas,
Iodides, bromides, chlorides and the like are mentioned. Again here
Compounds that react with silver ions to form poorly soluble compounds
Is the soluble silver formed by the silver halide solvent
Silver complex compound with higher stability and lower solubility than the complex
An organic compound that can form a substance, and is a particularly useful organic compound.
Thiol or thione group
Heterocyclic compounds and the like. [0010] However, the conventional method
Lithographic printing plates have an ink-receiving property
And stable printing performance cannot be obtained.
After processing, the undeveloped silver halide image area is selectively sensitized.
The processing time or temperature of the sensitization process in the processing process
Due to differences in the conditions of the lithographic printing plate
Capacity and press life can be significantly affected,
It had not yet been put to practical use. [0011] Accordingly, an object of the present invention.
Is the lithographic printing plate created by the method of (4) above.
In the sensitization treatment, especially treatment such as treatment temperature and treatment time
High ink receptivity and unaffected by differences in conditions
How to make a lithographic printing plate that can stably achieve high printing durability
Is to provide. [0012] The above-mentioned object of the present invention is to achieve the above object.
Exposure and development processing of a photographic material having a silver halide emulsion layer
Thereafter, the undeveloped silver halide image portion is selectively made lipophilic,
In preparing a lithographic printing plate to make it acceptable,
After the development of the material, at least one propylene
Organic compound having oxy group, mercapto group in molecule
Containing an organic compound having a silver halide solvent, and
Organic Compounds Having Mercapto Group in Molecule and Halogenation
A processing solution having a molar ratio of silver solvent of 1: 1 to 1: 8 (hereinafter referred to as a processing solution)
(Hereinafter referred to as post-sensitization treatment liquid).
Achieved by the method of making a printing plate. [0013] The present invention is included in the sensitizing solution of the present invention
Has at least one propyleneoxy group in the molecule
Organic compounds (hereinafter referred to as propyleneoxy derivatives),
Organic compounds having a mercapto group in the
Group-substituted organic compounds) and silver halide solvents
Each content greatly affects the printability of the lithographic printing plate.
Propyleneoxy derivative contained in the sensitizing solution of the present invention
The amount of body used is in the range of 0.1 g / L to 50 g / L.
And preferably within the range of 0.5 to 10 g / L.
The amount of the organic compound substituted with a rucapto group is 10 ^-Four Mol / L ~
0.1 mol / L is preferable, and the mercapto group
The molar ratio of the substituted organic compound to the silver halide solvent is 1:
The effect of the present invention is expressed in the range of 1-1: 8,
The content molar ratio is more preferably in the range of 1: 2 to 1: 6. [0014] Propylene contained in the sensitizing solution of the present invention
Hydroxy derivatives are propylene glycol, propylene
Derivatives based on oxy groups, polypropylene glycol
Coals, a mixture of ethyleneoxy and propyleneoxy groups
Glycols and propyleneoxy groups by repeating groups
And the like. Hereinafter, the present invention
Specific examples of propyleneoxy derivatives are given below.
It is not limited. The propylene oxide of the present invention
Two or more derivatives may be used in combination. Embedded image Embedded image Halogen contained in the desensitizing solution of the present invention
The silver halide solvent uses a silver complex salt diffusion transfer method (DTR method).
Is widely included in the processing system of the lithographic printing plate processing method.
It is well known and can be applied to the present invention. Halogen of the present invention
A silver halide solvent acts on silver halide and
A compound capable of forming a complex with high resolution,
Specific examples of the silver halide solvent used in the present invention
Is a sulfite (sodium sulfite, potassium sulfite
Thiosulfate (sodium thiosulfate, etc.), thiocyan
Acid salts (such as potassium thiocyanate), amines (ethylene
Diamine, etc.), alkanolamines (diethanol
Amine, N-methylmonoethanolamine, etc.), thioe
-Tels (3,6-dithia-1,8-octanediol
Thioureas (tetramethylthiourea, etc.), iodides
(Potassium iodide, sodium iodide, etc.), bromide (
Thorium, etc.) and chlorides (potassium chloride, etc.)
Thiocyanate is a particularly preferred silver halide solvent.
Potassium salt, 3,6-dithia-1,8-octanediol
, Potassium iodide and sodium iodide.
It is not limited to these. The halogen of the present invention
Two or more silver halide solvents may be used in combination. The mercap contained in the sensitizing solution of the present invention
G-substituted organic compounds react with silver ions to make them less soluble
And a compound that forms a compound with the silver halide solvent described above.
Is more stable than the soluble silver complex formed by
An organic compound that can form a silver complex compound with low solubility.
You. The mercap contained in the sensitizing solution of the present invention
The preferred structure of the organic compound substituted with a mercapto group is a mercapto group
Having a basic structure of a substituted aromatic ring or a nitrogen-containing heterocyclic ring.
And the number of mercapto group substitutions is within the same molecule.
There may be two or more, Japanese Patent Publication No. 57-3939,
Mercapto base described in Sho 61-23545
Alternative organic compounds may be used. Also, the mercap of the present invention
Two or more kinds of organic group-substituted compounds may be used in combination. Here, preferred are mercapto group-substituted organic compounds.
As a new aromatic ring or nitrogen-containing heterocyclic ring, benzene
Ring, pyridine ring, pyrimidine ring, pyridazine ring, pyrazine
Ring, imidazole ring, thiazole ring, oxazole
Ring, tetrazole ring, oxadiazole ring, thiadiazo
Ring, triazole ring, triazine ring, etc.
You. Mercapto group substitution contained in the sensitizing solution of the present invention
Specific examples of typical organic compounds
And 5- (n-heptyl) -2-mercapto-1,3,
4-oxadiazole, 2-mercapto-5- (n-pe
Methyl) -1,3,4-oxadiazole, thiosalithi
Phosphoric acid, 2-mercapto-1,3-benzimidazole,
2-mercapto-1,3-benzothiazole, 2-mer
Captopyridine-N-oxide, 6-dibutylamino-
2,4-dimercapto-1,3,5-triazine, 2,
4,6-trimercapto-1,3,5-triazine, 5
-Mercapto-1-phenyltetrazole, 1- (n-
Dodecanyl) -5-mercaptotetrazole, 2,5-
Dimercapto-1,3,4-thiadiazole, 3-mer
Capto-5-phenyl-4-acetamido-1,2,4
-Triazole, 2-mercaptonaphthalene, etc.
However, the present invention is not limited to these. The sensitizing solution of the present invention contains a silver halide solution.
Agent, propyleneoxy derivative, mercapto group substituted organic
Compound, but improves the solubility of the organic compound.
Methanol, ethanol, propanol,
Water miscibility of Tylene glycol, diethylene glycol, etc.
An organic solvent may be contained. The sensitizing solution of the present invention has a pH of 4 to 8.
It is preferably buffered. As a pH buffer
Are acids having a pKa value of 4 to 8, such as acetic acid, citric acid, phosphoric acid, etc.
And their salts. The conversion solution
May contain various other components. For example, hydroxye
Water-soluble polymers such as chill cellulose, colloidal
It may contain a surface hydrophilizing agent such as silica. In the present invention, undeveloped silver halide is ink-received.
This is a method of creating a lithographic printing plate by converting it to a container.
When the silver halide material is a negative type,
For printing plates and positive silver halide photosensitive materials
Gives a negative-type printing plate. The sensitizing solution of the present invention contains a surfactant.
(Such as propylene glycol alginate),
Minopolycarboxylate (ethylenediaminetetraacetic acid sodium salt)
) May be contained singly or in combination.
In order to prevent unevenness of the sensitization treatment, Japanese Patent Application Laid-Open No. 4-123
No. 53, an acetylene surfactant described in JP-A-9-30
It is possible to use the amino acid surfactant described in No. 4935.
it can. In the present invention, the treatment is performed before the sensitization treatment.
The development process does not include silver complex salt diffusion transfer development. Departure
Hydroquinone, as a developing agent of the developer used for lightening,
Chlorohydroquinone, bromohydroquinone, isop
Ropylhydroquinone, methylhydroquinone, 2,3
-Dichlorohydroquinone, 2,5-dichlorohydro
Quinone, 2,3-dibromohydroquinone, 2,5-di
Methyl hydroquinone, hydroquinone monosulfone
And others. In the present invention, in addition to the developing agent,
Nyl-3-pyrazolidone or a derivative thereof or p-amido
Nophenolic developing agents can be added. Concrete example
1-phenyl-3-pyrazolidone, 1-phenyl
-4,4-dimethyl-3-pyrazolidone, 1-phenyl
4-Methyl-4-hydroxymethyl-3-pyrazoli
Don, 1-phenyl-5-methyl-3-pyrazolidone,
1-p-aminophenyl-4,4-dimethyl-3-pyra
Zolidone, 1-p-tolyl-4,4-dimethyl-3-pi
Lazolidone and the like. P-aminophen used in the present invention
N-methyl-p-aminophen
NOL, N- (β-hydroxyethyl) -p-aminophen
Phenol, N- (4-hydroxyphenyl) glycine,
2-methyl-p-aminophenol, p-benzylamido
There are nophenol and the like, and among them, N-methyl-p-a
Minophenol is preferred. The developing agent is usually 0.03 mol / L to 0.8.
It is preferably used in an amount of mol / L. Also dihydro
Xybenzenes and 1-phenyl-3-pyrazolidones or
Is when a combination with p-aminophenols is used
The former is 0.1 mol / L to 0.5 mol / L, and the latter is 0.0 mol / L.
It is preferably used in an amount of 1 to 0.1 mol / L. As a preservative of the developing agent used in the present invention,
Sulfites, such as sodium sulfite, potassium sulfite
, Sodium bisulfite, potassium metabisulfite,
And sodium aldehyde bisulphite. The amount used
Although not particularly limited, preferably 0.05 mol / L to 1.
It is used in the range of 0 mol / L. In the developing solution, if necessary, a buffering agent (eg,
For example, carbonates, borates, alkanolamines, sulfo
Salicylic acid, etc.), alkaline agents (eg, sodium hydroxide)
, Potassium hydroxide, lithium hydroxide, etc.), dissolution aid
(Polyethylene glycols, their esters, etc.),
pH adjuster (for example, organic acid such as acetic acid), development acceleration
Agent, surfactant, hardener, etc.
You. The developing solution may further contain an antifoggant (for example, 5
-Nitroindazole, 5-nitrobenzimidazo
, 5-methylbenzotriazole, 5-nitrobenzo
Benzotriazole such as triazole, benzothiazo
Or 1-phenyl-5-mercaptotetrazole
Tetrazole, thiazole or British Patent 1,26
No. 9,268), chelating agents (examples)
For example, ethylenediaminetetraacetic acid, these alkali metals
Salt, polyphosphate, nitriloacetate)
Can be. As additives used in addition to the above components,
Is a development inhibitor such as sodium bromide and potassium iodide
Agent, ethylene glycol, diethylene glycol, tri
Ethylene glycol, N, N-dimethylformamide,
Methyl cellosolve, hexylene glycol, ethanol
And organic solvents such as methanol.
Includes toning agent, defoamer, water softener, etc. as needed
Is also good. The pH value of the developer thus adjusted is
Select enough to give the desired density and contrast.
However, it is desirable to be in the range of about 8-12. [0033] It can be used in the process of the present invention.
As an automatic developing machine, L manufactured by Dainippon Screen Mfg. Co., Ltd.
D281Q, LD360, LD381, LD480Q,
FG680A, FG950 manufactured by Fuji Photo Film Co., Ltd.
A, FG710A, etc., but limited to the type of automatic processor
Not. In addition, lithographic printing plates using silver salt diffusion transfer method
Automatic processors used for processing should also be used for processing.
Can be. The development processing temperature and time of the photographic material are mutually
Related and determined in relation to the total processing time,
Generally, it takes 10 seconds to 3 minutes at about 20 to 50 ° C.
In the case of treatment, it is 10 to 40 seconds at about 30 to 50 ° C.
You. Halogenation of photographic material used in the present invention
Silver is silver chloride, silver chlorobromide, silver bromide, including iodide
May be. The binder of the photographic material is preferably gelatin.
However, part or all of the colloidal substance is, for example,
Albumin, casein, polyvinyl alcohol, polyvinyl
Nyl alcohol-maleic anhydride, polyvinyl
Alcohol-styrene maleic anhydride, algi
It may be replaced with a phosphate or a cellulose derivative. Binder for silver halide, preferably
The weight ratio of gelatin and the absolute amount of binder are
An important factor in the production of a plate
You. When the amount of silver halide expressed as silver nitrate is 1
The amount of binder is preferably between 0.3 and 2.0. Join
When the ratio of the agent is 0.3 or less, the film strength as an emulsion layer is low.
Easy to remove and produce undesirable print characteristics.
Easy to do. On the other hand, when the ratio of the binder increases, the ink receiving
Tolerability may be reduced. The silver halide emulsion layer is made of
0.6 to 7 g / m in terms of silver acid amount ^Two , Converted to the amount of binder
0.18 to 2.1 g / m ^Two Preferably applied in
No. In the production of the printing plate of the present invention, other important
An important element is the hardened silver halide emulsion layer. At least
Must be fully cured before printing.
No. Emulsion layer coating solution is used in the same manner as the usual emulsion layer hardening method.
May be added during the process or before development and plate making.
Or at a later stage, for example, cured by a method such as heat treatment
Is also good. Includes curing agent for stable effect properties
After coating and drying the silver halide emulsion, it is heated appropriately
Is preferred. This heating treatment gives a good degree of hardening
For example, at 80 to 150 ° C.
Minutes or tens of minutes, or at 30-50 ° C for several days (1
(About 20 days). As a hardening agent, an ordinary silver halide emulsion
The compounds used as curing agents for the layers can be used.
For example, formalin, glyoxal, glutar alde
Aldehyde curing agents such as hide and mucochromic acid,
Urea-formalin condensate, melanin-formalin condensate
Is also effective, and epoxy and aziridine compounds
Products, activated olefins, isocyanate compounds,
Organic curing agents such as azines, chromium, aluminum,
Hardness of photographic emulsions such as inorganic polyvalent metal salts such as ruconium
Known compounds alone or in combination
Can be used. Further, the silver halide emulsion layer is
About 2 to 10 particles in size to prevent roid wear
Fine particles having a diameter of μm should be contained.
Mosquito, clay, talc, seek light, rice starch, etc.
Although it can be used, silica is particularly preferred. Silica is 0.01 to 1 square meter.
It is added to the silver halide emulsion so as to be 1 g. Siri
If the particle concentration is too high, the ink concentration
It is difficult to climb and causes scumming phenomenon
You. Photo sharpness, ultimately the resolution of the printed matter
So-called antireflective dyes or
It is preferable to apply a pigment. These are halogenated
In the silver emulsion layer or between the support and the silver halide emulsion layer
In the so-called anti-reflective layer, or between the supports
By applying it in the layer opposite the silver halide emulsion layer.
The purpose is achieved. Light-reflective pigments such as titanium oxide,
White pigments such as barium sulfate and magnesium oxide
Is a combination of a yellow organic pigment and a light-absorbing dye or pigment
The purpose is also achieved by using it. Photographic material in the method for producing a printing plate of the present invention
The most preferred embodiment is the use of an antireflective dye or
Has a colloidal undercoat layer having a pigment, and the undercoat layer
It has a silver halide emulsion layer thereon. A resin having the antireflection dye or pigment
The Lloyd undercoat layer is preferably made of gelatin, as described above.
Such fine particles having a particle size of 2 to 10 μm are contained. Suitable
The fine particles are silica. The gelatin binder is a square
0.5g to 2.5g per bottle, silver halide emulsion
It should be cured as well as the layer. Also, silica is one
Granted between 0.1g-20g per square meter
You. Contains fine particles as in the present configuration
The undercoat layer improves the abrasion of the colloid during printing,
It has the effect of improving printing durability. In this case the emulsion
In the layer, particulate silica is not necessarily required. The support for the silver halide emulsion is prepared according to the prior art.
Use any support commonly used in the field
it can. For example, paper coated on both sides with polyethylene,
Resin film such as ethylene terephthalate, metal
A sheet or the like can be used. In addition, surface activity is used to improve coating properties.
Agents, stabilizers for maintaining photographic sensitivity, anti-fogging
Stoppers, sensitizing dyes, developers, development accelerators and halogens
Dyes, pigments, etc. are optionally added for the purpose of coloring the silver halide emulsion layer.
Can be included. The present invention will be described in more detail with reference to the following examples.
However, it is not limited to this. (1) Production of photographic material Polyethylene terephthalate resin subjected to corona discharge machining
Silica particles (average particle size 5 μm) and carbon on the film
A gelatin undercoat solution containing black was applied. In addition, Zera
Add formalin and dimethylol urea as tin hardener
Was. The amount of gelatin and silica deposited is equivalent to one square meter.
The rust was 1.2 g and 0.7 g, respectively. Also,
The layer having a reflection density of 0.9. Next, this primer
Optically sensitized with a helium-neon sensitizing dye on the
Formalin and dimethylol urea as gelatin hardeners
Photographic materials coated with a silver halide emulsion layer of the following composition
Created a fee. Heat this photographic material at 40 ° C for 3 days
Was. Silver halide composition Silver chlorobromide (25 mol% of silver bromide) Average grain size of silver halide 0.33 μm Silver halide coating amount represented by silver nitrate 1.0 g / m 2 ^Two Gelatin coating amount 1.0g / m ^Two Silica (average particle size 5μm) coating amount 0.1g / m ^Two (2) Processing method The above photographic material was treated with a helium-neon laser light source (633).
exposing the image with an output machine having the following formula:
Solution and the sensitizing solution are respectively processed by an automatic processor LD221.
(Made by Dainippon Screen) into the first and second tanks,
The temperature of the developer in one tank was adjusted to 35 ° C., and under the conditions shown in Table 2,
After being treated and dried, a lithographic printing plate was obtained. <Developer> Water 600 ml EDTA · 2Na 1 g Sodium hydroxide 50 g Potassium sulfite 100 g Hydroquinone 55 g N-methyl-p-aminophenol 1/2 sulfate 0.8 g Potassium hydroquinone monosulfonate 40 g 5-methylbenzotriazole 0 0.2 g Potassium bromide 4 g The pH was adjusted to 11.80 using potassium hydroxide, and water was added to make up to 1 liter. <Degreasing Solution> Water 600 ml Diethylene glycol 50 g Sodium hydroxide 4 g Dipotassium hydrogen phosphate 25 g Mercapto group-substituted organic compound (referred to as compound M in Table 1) x molar silver halide solvent (in Table 1, silver solvent) Y mol propyleneoxy derivative (referred to as compound P in Table 1) zg Phosphoric acid (85%) was added to adjust the pH to 7.50, and water was added.
To 1 liter. Comparison shown in Table 1 and the present invention
Using a bright sensitizing solution (referred to as a sensitizing solution in Table 1)
Tested. [Table 1] 脂 Sensitized liquid Compound M / x silver Solvent / y x: y Compound P / z Ａ A (comparative) M1 / 0.0250 KI / 0.1 1: 4 B (comparative) M1 / 0.0100 KI / 0.1 1:10 P1 / 5 C M1 / 0.0167 KI / 0.1 1: 6 P1 / 5 D M1 /0.0250 KI / 0.1 1: 4 P1 / 5 E M1 / 0.0500 KI / 0.1 1: 2 P1 / 5 F M2 / 0.0250 KI / 0.1 1: 4 P1 / 5 G M1 / 0.0250 KI / 0.1 1: 4 P2 / 5 ────────────────────────────────── The compounds described in the table As the following things name
It is. <Compound M>M1; 5- (n-heptyl) -2-mercapto-1,
3,4-oxadiazole M2; 6-dibutylamino-2,4-dimercapto-
1,3,5-triazine <silver solvent>KI; potassium iodide <compound P>P1; tripropylene glycol P2; polypropylene glycol (average molecular weight = 100
0) [Table 2] 番号 No. Oil-sensitizing liquid Oil-sensitizing treatment condition (temperature / time) １ 1 (comparison) A 30 ° C / 30 seconds 2 (comparison) A 30 ° C / 45 seconds 3 (comparison) A 30 ° C / 60 seconds 4 (comparison) A 35 ° C / 30 seconds 5 (comparison) B 30 ° C / 30 seconds 6 (comparison) B 30 ° C / 45 seconds 7 (comparison) B 30 ° C / 60 seconds 8 (comparison) B 35 ° C./30 seconds 9 C 30 ° C./30 seconds 10 C 30 ° C./45 seconds 11 C 30 ° C./60 seconds 12 C 35 ° C./30 seconds 13 D 30 ° C./30 seconds 14 D 30 ° C./45 seconds 15 D 30 ° C./60 seconds 16 D 35 ° C./30 seconds 17 E 30 ° C./30 seconds 18 E 30 ° C./45 seconds 19 E 30 ° C./60 seconds 20 E 35 ° C./30 seconds 21 F 30 / 30 seconds 22 F 30 ° C./45 seconds 23 F 30 ° C./60 seconds 24 F 35 ° C./30 seconds 25 G 30 ° C./30 seconds 26 G 30 ° C./45 seconds 27 G 30 ° C./60 seconds 28 G 35 ° C. / 30 seconds────────────────────────── [0057] Then, the printing plate is set on the offset printing press.
And the plate surface was sufficiently wetted with an etchant having the following composition,
The printing was performed using the humidifying solution of the above. <Etch solution> Isopropanol 400 ml Ethylene glycol 50 g 2-mercapto-5-n-heptyl-1,3,4-oxadiazole 0.1 g Water is added to make 1 liter. <Humidifying liquid> Water 8 L Succinic acid 6 g Sodium sulfate 25 g Ethylene glycol 100 g Colloidal silica (20% aqueous solution) 28 g Printing and printing of Examples determined according to the following criteria
The results are shown in Table 3. Ink acceptance and printing durability test in printing
The result is shown. Ink receptivity is sufficient
Evaluation is based on the number of printed sheets until the degree is obtained.
And ○: up to 11 to 20 sheets, Δ: up to 21 to 30 sheets,
X: The evaluation was made in four steps of exceeding 31 sheets. Printing durability is an image
Is the number of prints when printing is not possible due to missing
50,000 or more, ○: 20,000 or more to less than 50,000, △: 5,000
More than ~ 20,000 sheets, ×; Evaluated in four stages of less than 5,000 sheets
Was. [Table 3] As is clear from the above results, the present invention
Higher stability and higher stability of sensitization process than comparison
A lithographic printing plate with ink receptivity and high printing durability was obtained.
Was.

Claims (1)

Claims: 1. A lithographic plate which comprises exposing a photographic material having a silver halide emulsion layer to light and developing, and then selectively lipophilicizing an undeveloped silver halide image to make it ink-receptive. In the production of a printing plate, after development processing of the photographic material, the photographic material contains an organic compound having at least one propyleneoxy group in a molecule, an organic compound having a mercapto group in a molecule, and a silver halide solvent, and The molar ratio of the organic compound having a mercapto group to the silver halide solvent is 1: 1 to 1: 8.
A method for preparing a lithographic printing plate, characterized by treating with a processing solution.