JPH049853A - Planographic printing plate for scanning type exposing - Google Patents

Abstract

PURPOSE:To obtain the planographic printing plate for scanning type exposing having a high sensitivity, hard contrast, high plate wear, high water retention, and excellent preservable property by incorporating a bisphenol type epoxy resin latex into a primer coating layer. CONSTITUTION:The bisphenol type epoxy resin latex is incorporated into the primer coating layer of the planographic printing plate for scanning type exposing having at least one primer coating layer, silver halide emulsion layer and surface physical development nucleus layer on a base. The planographic printing plate for which scanning type exposing light sources, such as laser beam and more particularly, semiconductor laser beam, IR laser beam and red light emitting diode, having the light emission wavelength within 600 to 800nm are used as light sources and for which the silver complex salt diffusion method of the high sensitivity, the hard contrast, the high plate wear, the high water retention, and the excellent preservable property is utilized is obtd. in this way.

Description

Detailed Description of the Invention (A) Industrial Application Field The present invention provides a silver complex salt suitable for use as a light source with a scanning exposure light source such as a laser beam, particularly a semiconductor laser beam, a red laser beam, and a red light emitting diode. This invention relates to a lithographic printing plate using the diffusion transfer method.

CB) Prior art and its problems A lithographic printing plate in which a transferred silver image obtained by the silver complex diffusion transfer method can be immediately used for ink receptivity has already been disclosed in Japanese Patent Publications No. 48-30562 and No. 53-2160.
2, 1972-103104, 1977-9750, etc., and are well known.

According to a typical implementation method of the silver salt diffusion transfer method suitable for the plate making method of such a lithographic printing plate, a support is provided, and a subbing layer that also serves as an antihalation layer, a silver halide emulsion layer, and a physical development nucleus layer are formed on the support. When a photosensitive material consisting of is imagewise exposed and developed, the silver halide on which a latent image has been formed becomes blackened silver in the emulsion layer. At the same time, silver halide on which no latent image has been formed is dissolved by the action of a silver halide complexing agent contained in the processing solution and diffused onto the surface of the photosensitive material. The silver complex salt that has been dissolved and diffused is deposited as a silver image on the physical development nuclei in the surface layer by the reducing action of the developing agent. After development and, if necessary, a sensitization treatment to enhance the ink receptivity of the resulting silver image, it is placed in an offset printing press and the ink image is transferred to a printed product.

According to the above conventional method, the silver halide emulsion layer is vector sensitized using a merocyanine dye, a cyanine dye, etc. so as to have a maximum sensitivity in the green region around 550 nm, and a plate-making camera with a normal light source such as a tungsten light source is used. Exposure was given for several seconds to several tens of seconds. However, the above conventional method has limitations even though the lithographic printing plate originally has excellent sharpness and resolution. Moreover, if one tries to obtain color printed matter from a color original, there are still problems in that not only the resolution is insufficient, but also the production of printing plates and plate-making operations are complicated.

Today, as a method for solving the above-mentioned problems, a method of direct plate making using laser light is being considered. For example, U.S. Patent No. 4,501°811;
61752, 1986-75838, 1986-100
148, 1986-114235, 1984-4775
6 discloses a lithographic printing plate used for helium-neon lasers, argon ion lasers-1 semiconductor lasers, light emitting diodes, and the like.

However, as described in the above patent specification, in lithographic printing plates using the silver complex diffusion transfer method, the surface physical development nucleus layer greatly affects the spectral sensitization, resulting in the desired sensitivity to laser light. In addition, as a result of silver complex salt diffusion transfer development, a soft transferred deposited silver image is formed, resulting in a decrease in sharpness and resolution, and furthermore, background smearing occurs, and silver images are printed. It has been difficult to obtain a lithographic printing plate of the desired high quality because sufficient printing durability may not be obtained due to cracking. Therefore, a sensitizing dye that meets these requirements must not only have sufficiently high sensitivity at the wavelength of laser light, but also have good storage stability and the ability to form a high-contrast transferred deposited silver image. , there must be no adverse effects such as scumming, and the ability to form strong transferred deposited silver that cannot be removed during printing even with minute amounts of silver must be satisfied.

Various types of lasers are known, but methods that use helium, neon, argon, and other laser light sources as scanner-type light sources can provide high output, and output devices equipped with these can achieve high image quality and high speed. It has characteristics that are associated with gender. However, the drawbacks are that the device is large and the power consumption efficiency is low.

On the other hand, semiconductor lasers have advantages such as being small, inexpensive, easy to modulate, and long life. Semiconductor lasers include Ga/As/P; Ga/At/As :G
Semiconductors of systems such as a/As; In/P; In/As are used, and the wavelength of this laser light is generally 700 m.
There are many wavelengths longer than μ (JC750mμ), but in recent years red semiconductor lasers with 680mμ have also been developed and are being put into practical use. Output devices equipped with these lasers are low cost and compact. However, it has the disadvantage of being inferior in image quality compared to the helium/neon laser output keyaki.

A lithographic printing plate using the silver complex diffusion transfer method that is suitable for using the above-mentioned scanning exposure light source as a light source has high sensitivity and satisfies the above-mentioned characteristics at the wavelength of the scanning exposure light source used. It has to be something.

Such properties also depend on factors such as the halogen composition of the silver halide emulsion, the silver halide grain size, and the type and degree of chemical sensitization. An emulsion containing mainly silver chloride as a halogenated steel has the advantage that diffusion transfer development occurs quickly and transfer deposited silver is easily produced to be used as an ink receiving area. However, the sensitivity is generally low, and if sufficient chemical sensitization is applied to achieve high sensitivity, the sensitivity to laser light becomes even lower.Also, if the diffusion transfer development is too fast, the printing strength of the transferred silver tends to become weaker.

Lithographic printing plates using the silver complex diffusion transfer method, which is suitable for using laser light, especially scanning exposure light sources such as semiconductor laser light, red laser light, and red light emitting diodes, have high sensitivity, high resolution, and high durability. It has been difficult to satisfy all of the above-mentioned requirements such as printing power and storage stability.

(C) Object of the invention The object of the invention is to provide laser light, particularly semiconductor laser light,
The light source is a scanning exposure light source with an emission wavelength in the range of 600 to 800 nm, such as a red laser beam or a red light emitting diode, and silver complex salt diffusion has high sensitivity, high contrast, high printing durability, high water retention, and excellent storage stability. Transfer method f! Our goal is to provide lithographic printing plates for our friends.

(D) Structure of the Invention The above object is to provide a lithographic printing plate for scanning exposure having at least one undercoat layer, a silver halide emulsion layer and a surface physical development nucleus layer on a support, in which the undercoat layer contains a bisphenol type. This is achieved by including epoxy resin latex.

Compounds with epoxy groups are disclosed in JP-A No. 51-103422.
, 59-94756, 60-191249, 60
As described in specifications such as No.-213941, it has been used for the purpose of improving adhesiveness. The present inventors employed the above-mentioned compound in a lithographic printing plate using a scanning exposure light source as a light source, and as a result of intensive study, they found that a bisphenol-type epoxy resin latex fully satisfies the object of the present invention. This effect is not observed in camera-type lithographic printing plates, and is a characteristic effect of lithographic printing plates using the scanning exposure light source of the present invention as a light source.

The bisphenol type epoxy resin latex used in the present invention is an emulsion of an epoxy resin synthesized by a known synthesis method as shown in the following formula (1).

The epoxy equivalent of the latex is not limited, but is preferably 500 or more.

The undercoat layer adjacent to the support of the present invention is
503, 1972-100203, 1972-5540
2.Sho 53-21602 or Sho 53-9603
As described in , the undercoat layer uses gelatin as a hydrophilic polymer, and the amount of bisphenol-type epoxy resin latex contained in the undercoat layer is relative to the gelatin Igr contained in the undercoat layer. 150111! -10QO”
F is a favorable factor.

Various types of gelatin can be used as the hydrophilic polymer used in the undercoat layer.
It can be replaced with hydrophilic colloids, sodium alginate, PVA, PVP, etc. described in 100554 and the like. Further, the undercoat layer may also serve as an antihalation layer, and further, various activators, hardeners, capping agents, and additives commonly used in the relevant field may be used as necessary. .

The red sensitizing dye used in the present invention may be any dye, for example,
1, 1983-39818, Japanese Patent Application Publication No. 59-71055,
It is a pigment known as JP-A No. 59-71056, etc., and is also known as JP-A No. 61-114235 and JP-A No. 62-62353.
It may be a combination of dyes described in , 1986-62354, etc. Specific examples of the red sensitizing dye used in the present invention are shown below, but of course, the present invention also applies to ] [1-E] CI-■] CI-J) 2H5 [11-K] (CH2)3 ■ 0s CI-H] 5OsH-N(C2Hs)s C5 CI-L) [11-A] [11 -B) SO5H-N(C2M5)3 1J3 [1-C) [:II-F] [-D) ■ 0s (n-G, 1 [1-E) (It-H:] [0s CII-I ] General formula CD C3Hn (CH2)3 O3 [n-J] The above dyes 1 and 2 can be used in combination.

In the present invention, in order to provide sensitivity applicable to semiconductor lasers, a sensitizing dye having an absorption peak on the wavelength side longer than 700 mμ can be used. The following general formula (1
) It is preferable to contain at least one sensitizing dye represented by:

(In the formula, Xl and X2Vi may be the same or different, each is an oxygen atom, N-R (R is an alkyl group)
, represents a sulfur atom or a selenium atom.

Zl and Z2 may be the same or different, and 5
Represents the atomic group necessary to form a nitrogen-containing heterocycle.

R1 and R2 may be the same or different and each represents an alkyl group or an alkenyl group.

R3 represents an alkyl group, an alkenyl group, or an aryl group. R4 represents a hydrogen atom, a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group. Y is a sulfur atom, N-
Ro (Ro is an alkyl group) represents an oxygen atom.

Q represents an atomic group necessary to form a 5- or 6-membered ring by linking with a carbon atom of a methine chain.

X represents an acid anion. ] Specific examples of Zl and Zl include thiazole, benzothiazole, naphtho[1,2-d]thiazole, naphtho[
,2,1-d]thianur,naphtho[2゜3-d,:]
Thiazole, selenazole, benzoselenazole, naphthoc2.1-d] selenazole, naphtho[1,2-d
:] selenazole, oxazole, benzoxazole, naph) [1,2-d:) oxazole, napf) [2,
Examples include nitrogen-containing heterocycles such as 1-d) oxazole, naphtho[:2.3-d]oxazole, 3,3-dialkylindolenine, imidazole, benzimidazole, naph)[1,2-d) imidazole, etc. can. These heterocycles include alkyl groups (e.g., methyl, ethyl, butyl, trifluoromethyl, etc.), aryl groups (e.g., fe, ;, tolyl, etc.), hydroxy groups, alkoxy groups (e.g., methoxy, ethoxy, butoxy, etc.), carboxy groups, alkoxycarbonyl groups (e.g., methoxycarbonyl, ethoxycarbonyl, etc.), halogen atoms (
For example, fluorine, chlorine, bromine, iodine), aralkyl group (
For example, it may have one or more substituents such as benzyl, phenethyl, etc.), a cyano group, and an alkenyl group (eg, allyl).

In R1 and R2, the alkyl group is methyl,
-/L/, lower alkyl groups such as propyl, butyl, β-
Hydroxyalkyl groups such as hydroxyethyl and γ-hydroxyglobil, alkoxyalkyl groups such as β-methoxyethinobe and γ-methoxypropyl, acyloxyalkyl groups such as β-acetoxyethyl, γ-acetoxypropyl, and β-benzoyloxyethyl, carboxymethyl ,
Carboxyalkyl groups such as β-carboquinethyl, methoxycarbonylmethyl, methoxycarbonylmethyl, β
-Alkoxycarbonylalkyl groups such as ethoxycarbonylethyl, β-sulfoethyl, γ-sulfopropyl,
and -sulfoalkyl group such as sulfobutyl, benzy/Iz
, acylkyl groups such as f+ethyl, sulfobenzyl, etc.
Examples of the alkenyl group include allyl.

Examples of R3 include the alkyl groups and alkenyl groups mentioned above for R1 and R2, as well as aryol groups such as phenyl, tolyl, methquinphenyl, talolophenyl, and naphthyl.

Examples of R4 include alkyl groups and aryl groups as described in R1 to R3 above, halogen atoms include fluorine, chlorine, bromine, and iodine, and alkoxy groups include methoxy, ethquine, propokino, and sulfopropoxy. etc. The ring represented by Q may be substituted with a lower alkyl group such as a methyl group.

Examples of the acid anion of It does not exist if .

Representative examples of the sensitizing dye for semiconductor lasers used in the present invention are shown below.

(I-1) U2F'i5 2 n5 CI-4) CI-5) CI-8) CI-6) CHpe) S03 Cl-11) The amount of the sensitizing dye used in the present invention is determined by the sensitizing dye. Although it varies depending on the type of dye or the type of silver halide photographic emulsion, it is usually 0.01 gr to 1 fine in terms of silver nitrate.
10gr can be used in a wide range, and when sensitizing dyes are combined, the total amount can be added within the above-mentioned range, and the mixing ratio of the combined dyes may be arbitrary. When adding a sensitizing dye to a silver halogenide emulsion, it can be added as a solution in a solvent such as methanol, isopropanol, pyridine, dimethylformamide, water, etc. alone or in combination. It is also possible to add ultrasonic dispersion to the emulsion. Additionally, U.S. Patent No. 3
, 482,981, 3,585,195, 3,469,987 and 2,912,343 may also be used.

In producing the silver halide emulsion for the lithographic printing plate of the present invention, various methods known in the photosensitive materials industry can be used.

The silver halide emulsion of the lithographic printing plate of the present invention is preferably at least 50 mol. Silver chloride, silver chlorobromide containing silver chloride of i70 mole or more, and a small amount (for example, 3 mole or less) of silver iodide mixed therein.The average grain size of these silver halide grains is preferably 0.2-0.8
It is in the micron range, but ranges other than this can also be used.

Furthermore, the silver halide is preferably a mono-diverse emulsion in which 90 percent or more of the total number of grains has a grain size within ±30 inches of the average grain size. Although silver halide grains are preferably substantially cubic or tetradecahedral, silver halide having other crystal habits may also be used.

The binder used in the silver halide emulsion of the lithographic printing plate of the present invention is usually gelatin. It can also be substituted with one or more hydrophilic polymer binders such as methylcellulose, polyacrylamide, styrene-maleic anhydride copolymer, and polyvinyl methyl ether-maleic anhydride copolymer. Furthermore, an aqueous vinyl polymer dispersion (latex) can also be used.

...A silver halide emulsion can be sensitized in a moderate manner when it is manufactured or when it is coated. For example, by sodium thiosulfate, gold alkylthiochloride,
Alternatively, it is preferable to chemically sensitize by a method known in the art, such as a combination of both.

In addition, at any time during the production of the halogenated emulsion, compounds of metals belonging to Group Ⅰ of the periodic table, such as cobalt,
By using salts such as nickel, rhodium, palladium, iridium, platinum, etc., it is possible to obtain properties particularly favorable for printing plates for direct plate making, such as high sensitivity, high sharpness, and high resolution. The amount added is in the range of 10-8 to 10'-3 mol per mol of silver halide. The silver halide emulsion layer may contain other conventional additives such as fabrication aids, antifoggants, matting agents (water retention agents), and developing agents.

An undercoat layer may be provided below the silver halide emulsion layer (on the support side) for the purpose of improving adhesion and/or preventing halation, and this layer may contain a developer, a capping agent, etc. 8 is coming too.

The lithographic printing plate of the present invention has an image-receiving layer containing physical development nuclei.

As the physical development nucleus, known ones such as metals such as anti-hetamine, bismuth, cadmium cobalt, palladium nickel, silver, lead, and zinc, and their sulfides can be used. The image-receiving layer does not need to contain hydrophilic colloids and may include gelatin, carboxyl methylcellulose, gum arabic, sodium alginate, droxyethyl starch, dextrin, hydroxyethylcellulose, polystyrene sulfonic acid, and a copolymer of vinylimidazole and acrylamide. , polyvinyl alcohol, etc., preferably in an amount of up to 0.1 grams per square meter.

Hygroscopic substances such as humectants such as sorbitol, glycerol, etc. may be present in the image-receiving layer. Furthermore, the image-receiving layer may also contain pigments for anti-scamming such as barium sulfate, titanium dioxide, china clay, and silver, developing agents such as hydroquinone, and hardening agents such as formaldehyde.

Supports include, for example, paper, films such as cellulose acetate films, polyvinyl acetal films, polystyrene films, polypropylene films, polyethylene terephthalate films, or composite films coated with polyethylene films such as polyester, polypropylene or polystyrene films, metals, metals, etc. It can be a support of synthetic paper or metal/paper laminate. Paper supports coated on one or both sides with an alpha-olefin polymer, such as polyethylene, are also useful. These supports include
Antihalation dyes or pigments may also be incorporated.

The DTR treatment liquid used in the present invention includes an alkaline substance,
For example, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium triphosphate, etc., sulfites as preservatives, silver halide solvents, such as thiosulfates, thiocyanates, cyclic imides, thiosalicylic acid, amines, etc. thickening agent,
For example, hydroxyethylcellulose, carboxymethylcellulose, antifoggants such as potassium bromide, 1-
Phenyl-5-mercaptotetrazole, JP-A-47-
26201, developers such as hahydroquinone, 1-phenylene, nyl-3-hydrochloride, development modifiers such as polyoxene alkylene compounds, onium compounds, and the like.

For implementing the silver complex diffusion transfer method, for example, British Patent No. 1,000,115, British Patent No. 1,012,476,
No. 1,017,273; is being mixed in. Therefore, for such materials, the processing solution used in the development step may be a so-called "alkaline activating solution" that does not contain a developer.

The lithographic printing plate produced according to the present invention is, for example,
-29723, and compounds such as those described in U.S. Pat. No. 3,721,539, can convert or enhance ink receptivity.

The printing method, the desensitizing liquid, the dampening liquid, etc. used can be any commonly known method.

(E) Examples The present invention will be explained below using examples, but it is of course not limited thereto.

EXAMPLE A matting layer containing silica particles having an average particle size of 5 μm is provided on one side of a polyester film support, and an undercoat layer serving as an antihalation layer is coated on the opposite side as described below.

Undercoat layer> Gelatin 25gr matting agent (silica powder) 6gr carbon black dispersion (solid content 32%) 1.5gr surfactant 3-formalin
Add 0.2 gr water to bring the total volume to 45
Make it 0 gr. Application f is 45-/I in terms of moisture application amount.

A bisphenol type epoxy resin latex (epoxy content: 900) was added to the above undercoat layer as described below.

A silver halide emulsion layer containing 5% by weight of silica powder based on photographic gelatin is provided on the undercoat layer.

A silver halide emulsion was first prepared by conventional physical ripening. 5 x 10 per mole of silver halide during physical ripening
molar of iridium is added, and the silver halide grains have an average grain size of 0.33 microns, ±30% of the average grain size.
It was a substantially cubic silver chloride crystal with 90% or more of the total number of grains distributed in the range of . Subsequently, chemical sensitization was performed using a gold compound and hypo, and then spectral sensitization was performed by adding a red sensitizing dye or a sensitizing dye for semiconductor lasers. Also, for comparison, Orn sensitization was carried out for camera type use.

Gelatin in the emulsion layer is 1.2 gr, /+', silver halide 1-5 gr/W converted to silver nitrate? was applied at the rate of

Further, the emulsion layer contains formalin as a hardening agent in an amount of 28 .mu./2 gelatin to gelatin.

After coating and drying, after heating at 40°C for 7 days, % Example 1 of Japanese Patent Publication No. 1983-103104 was applied on top of this emulsion layer.
Hydroquinone 0.8 was added to the core coating liquid on plate 11.
Prepare the solution in the same manner by adding it so that it becomes f/m',
Coated.

633nm or 780n for sensitometry
Each of the planographic printing plates was exposed to light for 10 -6 seconds in close contact using an interference filter of 0.0 m and a wafer with a tolerance of 0.15.

On the other hand, the printing test sample was Helium Neo 7'L/
-Zertaib Center Linotronic 300
(L1notype GJ) Alternatively, halftone dots and fine line images were created by fogging using Alkylenta (manufactured by Altre Co., Ltd.).

Samples of camera type lithographic printing plates were prepared using conventional methods.

In order to test the storage stability of the lithographic printing plate of the present invention, samples were prepared by forced heating at 50° C. for 4 days.

Samples for photographic properties tests and printing tests were obtained in the same manner as described above.

Each exposed printing plate was treated with the following diffusion transfer developer.
Developed at 5° C. for 30 seconds. After the development process, the original plate was passed between two squeezing rollers to remove excess developer, and immediately treated with a neutralizing solution having the following composition at 25°C for 20 seconds, and the excess liquid was removed using a squeezing roller. , dried at room temperature.

<Diffusion transfer developer> Potassium hydroxide anhydrous sodium sulfite 2-mercaptobenzoic acid uranium neutralizing liquid> Pressing durability is determined by pasting each printing sample onto a sheet and placing this sheet in an offset printing machine. The following desensitizing liquid was applied all over the plate surface, and printing was performed using the following dampening liquid.

The printing machine is N.B.Dick 350CD (A・B-
A trademark of an offset printing machine manufactured by DICk was used.

Non-greasy liquid> Add water to make a total volume of 1 ton.

Table 1 shows the water retention properties of the fresh sample C (unheated) and the forced heating sample.

The sensitivities of the lithographic printing plates in Table 1 are relative sensitivities, with the sensitivity of the comparative sample being 100. The printing durability was evaluated based on the number of sheets that could not be printed due to silver flying, and the following criteria were used.

1. 4,000 sheets or less 2. 4,000-6,000 sheets 3. 6,000-s, o o o sheets 4. 8,000-10,000 sheets 5. 10,000 sheets or more Also, water retention For this, a forced test was conducted using water instead of the dampening liquid, and evaluation was made based on the number of sheets that started to become soiled.

As is clear from Table 1, the relative sensitivity, gamma, printing durability, and (F) effect of the invention of each lithographic printing plate, the present invention provides high sensitivity, high contrast, high printing durability, high water retention, and storage stability. It can be seen that a lithographic printing plate for scanning type exposure with excellent properties can be produced.

Claims (1)

[Claims] (1) In a lithographic printing plate for scanning exposure having at least one undercoat layer, a silver halide emulsion layer, and a surface physical development nucleus layer on a support, the undercoat layer contains a bisphenol-type epoxy resin latex. A lithographic printing plate for scanning exposure characterized by: