JPS6029751A - lithographic printing plate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lithographic printing plate using a silver complex diffusion transfer method suitable for plate making using a light emitting diode exposure device.

Lithographic printing plates in which a transferred silver image obtained by the silver complex diffusion transfer method can be used immediately as ink receptivity have already been published in Japanese Patent Publication No. 48-30562, Closed Patent Publication No. 53-21602, Denkaho No. 54-103104, 56-9750, etc., and is well known.

According to a typical implementation method of the silver complex diffusion transfer method suitable for the plate-making method of such a lithographic printing plate, a support is provided, and a subbing layer for preventing halation, 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 the 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 of the surface layer by the ring element 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.

In conventional methods, the silver halide emulsion layer is spectrally sensitized using merocyanine dyes, cyanine dyes, etc. so that it has a maximum sensitivity in the green region around 550 nm.
A prepress camera with a normal light source such as a tungsten light source provides exposure 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 way to solve the above-mentioned problems, high-intensity, short-time (
Direct plate making using a scanning exposure method (10 seconds or less) is considered, but as is well known, these exposure methods result in high-intensity reciprocity failure, resulting in unsatisfactory characteristics such as low sensitivity and soft contrast. . Especially the light emitting diode
(LED) has a lower output than neon-helium laser light, so it has higher sensitivity, higher contrast, sharpness, and resolution, and it also prevents background smudges and silver images from coming off during printing. A lithographic printing plate is required. Therefore, sensitizing dyes that meet these requirements generally have not only stable and high sensitivity, but also good storage stability, the ability to form high-contrast transferred deposited silver images, and the ability to prevent scales and background stains. All conditions must be satisfied, such as the absence of negative effects such as the formation of strong Hiko-transfer deposited silver that cannot be removed during printing even with minute amounts of silver, and the like.

JP-A No. 53-21601 describes the use of betaine or anionic cyanine sensitizing dyes as offset printing plates with high sensitivity and improved printing characteristics, and silver bromide is used to obtain high sensitivity. It has also been shown that it is preferable to use a high content Nolog/silver oxide emulsion. On the other hand, it is known that silver chloride emulsions with a high silver chloride content have lower spectral sensitization effects in high-intensity, short-time exposures (for example, Japanese Patent Publication No. 48-4217
2), -j is also known to have a large high-intensity reciprocity law failure (for example, Photographic, Science, & Engineering/Gineering, Vol. 26, 1982), and is generally unsuitable as an emulsion for LEDs. However, by using a specific sensitizing dye in a silver chloride emulsion containing a large amount of silver chloride, the present inventors have achieved sufficiently high sensitivity to exposure using an LED as a light source, and improved printing characteristics. Good 'fx, iron complex expansion 1? We have discovered that a lithographic printing plate can be obtained using a transfer method.

An object of the present invention is to provide a lithographic printing plate using an anchor complex diffusion transfer method that is highly sensitive to exposure using an LED as a light source and has good printing characteristics.

The above object of the present invention is to provide a light-emitting diode as a light source, characterized in that a silver chloride emulsion layer containing at least 70 moles of silver chloride contains a red sensitized color represented by the following general formula CI). Coupled with a lithographic printing plate for complex salt diffusion transfer.

General formula (I) In formula (I), R2 is an alkyl group (e.g., methyl group, ethyl group, propyl group, butyl group, β-sulfoethyl group, γ-sulfopyl group, 1-sulfobutyl group, Vinyl methyl group, β-carboxyethyl group, 1-
carboxypropyl group, δ-carboxybutyl group, etc.),
Represents an alkenyl group, aryl group, aralkyl group,
, and at least one of R.2 is a group having a sulfo group or a carboxyl group. "31 R4 is a hydrogen atom, an alkyl group, an alkoxy group, an aryl group,
It represents a hydroxyl group, an alkoxycarbonyl group, or a halogen atom, and R4 and R4 may form a benzene ring. (2) t5 represents an argyl group, an aryl group, or an aralkyl group. Y, , Y2 represent 8 atoms and SC atom, respectively. X represents a cation such as hydrogen, an alkali metal, or ammonium. m represents 1 or 0.

Next, typical sensitizing dyes used in Kinei 13)] are illustrated.

Pigment 8゜ The dyes used for comparison are shown below.

Recipe B The sensitizing dye used in the present invention can be synthesized by a method known to those skilled in the art. The addition to the silver halide emulsion can be at any time during coating of the emulsion. The amount added can vary within a wide range, but good results have been obtained from 1 x 10-5 to 1 molar silver halide.
It is in the range of Xl0-2 moles. The optimum amount to be added varies depending on the conditions of the silver halide emulsion, such as the halogen composition, the average grain size of the silver halide grains, and the crystal habit.

The silver halide emulsion of the lithographic printing plate of the present invention preferably contains 70 mol% or more of silver chloride, such as silver chloride, silver chlorobromide, or silver chlorobromoiodide.
Silver halide containing 80 mol% or more. The average grain size of these silver halide grains is preferably 02 to 06
It is in the micron range, but ranges other than this can also be used. Further, the silver halide is preferably a monodispersed emulsion in which 90 percent or more of the total number of grains has a grain size within 30% of the average grain size.

In addition, the silver halide preferably has substantially cubic to tetradecahedral grains, but silver halide having other crystal habits can also be used.

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

Silver halide emulsions can be sensitized in a variety of ways when they are manufactured or coated. Preferably, it is chemically sensitized by methods well known in the art, such as by sodium thiosulfate, alkylthioureas, or by gold compounds such as rhodan gold, gold chloride, or a combination of both.

Furthermore, compounds of metals belonging to Group 1 of the periodic table, such as salts of evaporated cobalt, nickel, rhodium, palladium, iridium, platinum, etc., can be used at any time during the production of the silver halide emulsion. The amount added is in the range of 10-8 to 10-3 mol per mol of silver halide. The silver halide emulsion layer can contain other conventional additives such as coating 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 matting agent, etc. You can also do it.

The lithographic printing plate of the present invention has an image-receiving layer containing physical development nuclei. Physical development nuclei include antimony, bismuth,
Known metals such as 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, carboxymethylcellulose, gum arabic, sodium alginate, hydroxyethyl starch, textrin, hydroxyethylcellulose, polystyrene sulfonic acid, and a copolymer of vinylimidazole and acrylamide. Hydrophilic colloids, such as polyvinyl alcohol, may be included, preferably in amounts of up to 0.01 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 preventing scumming such as barium sulfate, titanium dioxide, Teyaina clay and silver, developing agents such as hydroquinone, and hardening agents such as formaldehyde.

The support can be, for example, paper, a film such as a cellulose acetate film, a polyvinyl acetal film, a polysterene film, a polypropylene film, a polyethylene terephthalate film, or a composite film such as a polyester, polypropylene or polystyrene film coated with a polyethylene film, metal, metallized. It can be a paper or metal/paper laminate support. Paper supports coated on one or both sides with an alpha-olefin polymer, such as polyethylene, are also useful. These supports include
/・May contain anti-rayon dye or pigment.

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 chloride solvents, such as thiosulfates, thiocyanates, cyclic imides, thiosalicylic acid, amines. etc., thickening agents such as evaporative hydroxyethyl cellulose, carboxymethyl cellulose, antifoggants such as potassium bromide, 1
-Phenyl-5-mercaptotetrazole, JP-A-47
-26201, a developer such as hydroquinone, 1-phenyl-3-pyrazolidone, a developer modifier such as a polyoxyalkylene compound, an onium compound, and the like.

In carrying out 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 liquid used in the development step may be a so-called "alkaline activating liquid" which does not contain a developer.

The lithographic printing plate manufactured according to the present invention is, for example,
8-29.723, U.S. Pat. No. 3,721,539, etc., the ink receptivity can be changed or enhanced.

As for the printing method, the desensitizing liquid, dampening liquid, etc. used can be carried out by commonly known methods.

The present invention will be explained below with reference to examples, but of course it is 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 polyester film support, and a matting layer containing carbon black on the opposite side, containing 20% by weight of photographic gelatin. Antihalation undercoat layer containing silica powder with an average particle size of 7 μm (adjusted to pH 4.0)
and a spectrally sensitized high-sensitivity silver chloride emulsion layer (pH 4,
(adjusted to 0).

The gelatin in the undercoat layer was coated at a rate of 3.0 f/m', the gelatin in the emulsion layer was coated at a rate of ], Of//m', and the silver halide, converted to silver nitrate, was coated at a rate of 1.0 f/m'.

The undercoat layer and emulsion layer contain formalin as a hardening agent and gelatin at a concentration of 5.0 mf/? Contains an amount of gelatin. After drying and heating at 40°C for 14 days, a core coating liquid (the polymer is a copolymer of A3 acrylamide and imidazole) described in Example 2 of JP-A-53-21602 was applied on top of this emulsion layer. , hydroquinone is 0.81F/m
) is coated and dried to produce a lithographic printing plate. When the silver halide emulsion is physically ripened, the silver halide emulsion becomes
Add 5 x 10-6 moles of rhodium chloride per mole
The crystals had an average particle size of 0.45 microns, and more than 90!6 of the total number of particles were distributed within the range of ±3096 ±3096 of the average particle size, and were collectively cubic crystals.

As sensitizing dyes used in iron halide emulsions, dyes shown in Table 1 below were used at a concentration of 3 x 10-' per mole of silver halide.
Eight types of lithographic printing plates were manufactured using the same method as described above except that molar addition was used.

Light emitting diode exposure device (wavelength: approx. 670 to approx. 680 nn)
1) A 10 second exposure was given using one scanner.

After exposure, development was performed using the following diffusion transfer developer fJ solution.

<Transfer developer> After the development f9 processing, the original plate is passed between two squeeze rollers,
Remove the excess developer and immediately use a medium-sized oven with the following composition.
The sample was treated with liquid at 25°C for 20 seconds, excess liquid was removed using a squeezing roller, and the sample was dried at room temperature.

Sensitivity and sharpness of each lithographic printing plate, solution f? The forces are shown in Table 1. The sensitivity is the r! required to stop forming transfer deposits. It is expressed as a relative power with π light intensity and sensitizing color base 1 as sensitizing color base 4. In addition, the sharpness and resolution are 10 (+, 133
．． Using 150.175 and 20 o@/inch, the screen divisor was rated from t (xoo gland/inch) to 5 (20 o brocade/inch) based on the screen divisor on which the minute halftone dots (5 taro dots) could be clearly reproduced. ) on a five-point scale.

Desensitizing liquid〉〉〈Moistening liquid〉 The printing machine is a NiB Dick 350CD (A-B-
The Dick offset printing press trademark was used. The printing durability based on the number of sheets that could not be printed due to the occurrence of scumming or silver scattering was evaluated according to the following criteria, and is shown in the right column of Table 1.

Each lithographic printing plate shown in Table 1 was mounted on an offset printing machine, the following desensitizing liquid was applied all over the print, and printing was carried out using the following dampening liquid.

1. 4,000 sheets or less 2. 4,000-6,000 sheets 3. 6,000-s, ooo sheets 4. 8,000-10,000 sheets 5. 10,000 sheets or more The lithographic printing plate of the present invention It can be seen that although it has minute halftone dots, it has a high printing durability. It was also confirmed that the lithographic printing plate of the present invention is stable and does not lose its properties even when stored for a long period of time.

Example 2 Four types of silver bromide emulsions were prepared in exactly the same manner except that the silver chloride emulsion of Example 1 was replaced with a silver chlorobromide emulsion and a silver bromide emulsion containing 5, 5, 50, and 100 mol% of silver bromide. An emulsion was produced. Four types of lithographic printing plates were prepared according to Example 1 using Dye 1 in these emulsions and tested in the same manner. The results are shown in Table 2.

Schedule 2 Procedural Amendment Letter issued) September 7, 1980 Manabu Shiga, Commissioner of the Patent Office! 1.1L, Incident Indication 1981 Patent Application No. /3 /3 &δ -J-
2. Name of the invention (M6rPJ)rL 3. Relationship with the case of the person making the amendment Patent applicant office 4-2 Marunouchi Otsu-chome, Chiyoda-ku, Tokyo Name (
598 Seal 1 Funuki Co., Ltd. 4, Agent address: 5, Mitsubishi Paper Mills Co., Ltd., 3-4-2 Marunouchi, Chiyoda-ku, Tokyo 100, Japan Date of amendment order: Showa Month, Day 6, Number of inventions increased by amendment 7. Column for detailed explanation of the invention subject to amendment (1) qt+aJttyr t-s i 6ttmF
d element action t 1 L element bu 乍 ) PI θ to d ``positive (2) ノ4
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Claims (1)

[Scope of Claims] l) A light source is a light emitting diode characterized by containing a sensitizing dye of the following general formula (I) in an iron oxide emulsion containing at least 70 mol% of silver chloride. Lithographic printing plate for silver complex diffusion transfer. General formula σ) (In the formula, ■1.R2 is an alkyl/I/ group, an alkenyl group,
It represents an aryl group or an aralkyl group, and at least one of R1 and R2 is a group having a sulfo group or a carboxyl group. R3 and R4 represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, a hydroxyl group, an alkoxycarbonyl group, or a halogen atom; and may form a benzene ring. R5 represents an alkyl group, an aryl group, or an aralkyl group. Yl and Y2 represent a sulfur atom and a selenium atom. X represents a cation, and m is 1 or O. )