JPH07199470A - Planographic plate - Google Patents

Abstract

PURPOSE:To significantly enhance the water retaining property and print quality of a planographic printing material which adopts silver complex salt diffusion transfer method. CONSTITUTION:A planographic printing material, having at least a halation preventing layer, a silver halide emulsion layer and a physical development nucleus layer on a support, and adopting silver complex salt diffusion transfer method, contains at least one flat mat agent in at least either the halation preventing layer or the silver halide emulsion layer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a lithographic printing material to which a silver complex salt diffusion transfer method is applied.

[0002]

2. Description of the Related Art A lithographic printing plate is composed of an oleophilic image-forming portion that accepts oil-based ink and an oil-repellent non-image-forming portion that does not receive ink. It is composed of sex parts. In ordinary lithographic printing, both water and ink are supplied to the plate surface, the image area selectively receives the coloring ink, and the non-image area selectively receives water, and the ink on the image area, such as paper Printing is performed by transferring it to a printing medium.

Therefore, in order to obtain a good printed matter, the difference in lipophilicity and hydrophilicity between the image area and the non-image area is sufficiently large, and the image area is sufficient when water and ink are supplied to the plate surface. It is necessary to accept a certain amount of ink and not to accept ink in the non-image area.

A lithographic printing plate using a silver complex salt diffusion transfer method (DTR method), particularly a lithographic printing plate having a physical development nucleus layer on a silver halide emulsion layer is described in, for example, US Pat. No. 3,72.
No. 8,114, No. 4,134,769, No. 4,1
No. 60,670, No. 4,336,321, No. 4,
No. 501,811, No. 4,510,228, No. 4,621,041 and the like. The exposed silver halide crystals cause chemical development by DTR development to give a black color. It becomes silver and forms a hydrophilic non-image area, while unexposed silver halide crystals become a silver salt complex by the silver salt complexing agent in the developing solution and diffuse to the physical development nucleus layer on the surface to form nuclei. In the presence of the above, physical development is caused to form an image area mainly composed of ink-receptive physically developed silver.

As described above, in the planographic printing plate, gelatin-
Since the silver image deposited on the physical development nucleus layer on the silver halide emulsion layer is used as the ink-receptive image area, the image area is larger than that of a general lithographic printing plate (eg PS plate). There is a defect that the resistance to mechanical abrasion of the image part is insufficient, the image part is missing, and the ink receiving property of the image part is gradually lost.

In order to overcome this drawback, the hardness of gelatin is increased, a matting agent is added to an antihalation layer or a silver halide emulsion layer to improve abrasion resistance, and the amount of physical development nuclei is increased. When it increased, scumming occurred. Further, when the planographic printing plate is manufactured and stored for a long period of time from the time when the plate is made, there are drawbacks such that scumming occurs and the ink receptivity deteriorates.

Further, if the hardness of gelatin is increased or the amount of physical development nuclei is increased, uneven coating properties of the physical development nuclei layer frequently occur, and the printing durability is seen in the unevenness. Dirt,
The effects on ink deposits and ink deposits are seen, and improvements are desired.

To improve water retention, Japanese Patent Application No. 3-6
No. 5545, it was proposed to include pullulan in the physical development nucleus layer or / and the layer adjacent thereto.
The level of improvement effect was not enough. Also, it cannot be said that the ink-repellency is sufficiently good.

In order to improve the printing durability, Japanese Patent Publication Nos. 62-296143, 63-226658 and 63-63658.
Various matting agent technologies have been proposed in No. 249852, Japanese Patent Publication No. 1-261643, JP-A No. 5-100430, No. 5-80518, No. 5-80519, and No. 5-80520. The printing durability, water retention, ink build-up, print image quality, and scratch resistance were not sufficiently satisfied.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a silver complex salt diffusion transfer method which is excellent in various printing characteristics (printing durability, water retention, ink buildup, etc.) and is particularly improved in water retention and print image quality. It is to provide the lithographic printing plate used. Another object of the present invention is to provide a lithographic printing plate using a silver complex salt diffusion transfer method with improved image reproducibility in a back-printed lithographic printing plate.

[0011]

The above object of the present invention is to provide an antihalation layer and a silver halide photograph in a lithographic printing plate having at least an antihalation layer, a silver halide emulsion layer and a physical development nucleus layer on a support. It was achieved by including a tabular matting agent in at least one of the emulsion layers.

The flat matting agent used in the present invention includes sericite talc, mica, flow beads (a thin plate of polyolefin resin such as polyethylene, manufactured by Iron Manufacturing Chemical Co., Ltd.), synthetic mica (made by Corp Chemical KK). ) And the like, all of which can be obtained from Yuka Sangyo Co., Ltd., but are not limited thereto.

As a means for solving the problems of the present invention, the most suitable tabular matting agent is most preferably synthetic mica which can be selected in various sizes and types and can be arbitrarily synthesized.

As the synthetic mica of the present invention, those having a particle size of 1 to 25 μm can be obtained. They are MK-100, MK-200, and MK-100, respectively.
MK-300 There is ME-100 series which is more swellable, and it is made of talc as the main raw material and is a high-purity tetrafluorosilicon mica.

The tabular matting agent of the present invention can be used in combination with other matting agents (spherical, amorphous, etc.), and its effects can be further utilized. The amount of the tabular matting agent used is influenced by the amount of the matting agent used together and the amount of the binder, but is preferably 0.1 to 4 g / m ² and more preferably 0.5 to ² g / m ² . The flat matting agent of the present invention has a higher surface smoothness than other matting agents even when used in a large amount and is superior in print image quality and water retention. On the other hand, it was also found that the flat matting agent of the present invention is excellent in image reproducibility in the back-baked planographic printing plate. It can be expected that scratch resistance in the development process will be improved by using a larger amount.

On the other hand, in Japanese Patent Application No. 5-18964,
A combination of a methylolated product of acrylic amide and a water-soluble polysaccharide has also been proposed, but the effect of the polymer in these physical development nucleus layers can be further brought out by the surface smoothness of the tabular matting agent of the present invention, Further, the water retention can be improved.

The tabular matting agent used in the present invention can be contained in the antihalation layer and the silver halide photographic emulsion layer, and the ratio thereof can be arbitrarily determined, but it is often used in the silver halide photographic emulsion layer. And the printing durability decreases, and more preferably in the range of 0 to 0.2 g / m ² . (Of course, it depends greatly on the amount of binder.)

The aspect ratio of the flat matting agent of the present invention is preferably from 5 to 100, more preferably from 20 to 60. When the aspect ratio is 5 or less, the effect of being flat is small, and 1
When it is 00 or more, the effect as a matting agent is small, and improvement in printing performance cannot be expected.

The aspect ratio is the ratio of the length of the horizontal side to the vertical side of the shooting field of view or the projection screen in the photographic term, and the aspect ratio. The aspect ratio mentioned here is the same as the silver halide grains (tabular grains) of the silver halide photographic light-sensitive material. That is, it is represented by the ratio of the diameter / thickness of the flat matting agent.

The lithographic printing plate which is the object of the present invention contains gelatin, and its content may be an antihalation layer, an emulsion layer or a physical development nucleus layer. These gelatin contents can be hardened with a gelatin hardener. Examples of gelatin hardeners include inorganic compounds such as chromium alum, aldehydes such as formalin, glyoxal, malealdehyde and glutaraldehyde, N-methylol compounds such as urea and ethyleneurea, mucochloric acid, and 2,3-dihydroxy-. Aldehydes such as 1,4-dioxane, compounds having active halogen such as 2,4-dichloro-6-hydroxy-S-triazine salt and 2,4-dihydroxy-6-chloro-triazine salt, divinyl sulfone, divinyl ketone and N, N , N-triacroylhexahydrotriazine,
It is possible to use one or more of various compounds having two or more ethyleneimino groups or epoxy groups which are active three-membered rings in the molecule, and various compounds such as dialdehyde starch as a polymer hardener. it can.

The hardener can be added to all layers or to some or only one layer.
Of course, the diffusible hardener can be added to only one layer in the case of simultaneous coating of two layers. As an addition method, it may be added at the time of emulsion production or in-line at the time of coating.

The gelatin in the gelatin-containing layer of the present invention comprises a part of water-soluble gelatin, starch, dextrin, albumin, sodium alginate, hydroxyethyl cellulose, gum arabic, polyvinyl alcohol, polyvinylpyrrolidone, carboxymethylcellulose, polyacrylamide, styrene. It may be substituted with one or more hydrophilic polymers such as a maleic anhydride copolymer and a polyvinyl methyl ether-maleic anhydride copolymer. Further, an aqueous vinyl polymer dispersion (latex) can be added to the gelatin layer.

The polymeric binder in the antihalation layer is generally 0.5 to 10 g / m ^2, more preferably 1 to 6 g / m ^{2.
Is 2} . The undercoat layer may contain a pigment such as carbon black, a dye or the like for the purpose of preventing halation, and may contain a solid powder (for example, silica particles) having an average particle diameter of 2 to 10 microns for improving printing durability. Further, photographic additives such as developing agents can be included. The antihalation layer is disclosed in JP-A-48-5503 and JP-A-48-10020.
No. 3 and No. 49-16507 may be used.

The silver halide emulsion layer is, for example, silver chloride,
It comprises silver bromide, silver chlorobromide, and those containing silver iodide. The silver halide crystal may contain a heavy metal salt such as a rhodium salt, an iridium salt, a palladium salt, a ruthenium salt, a nickel salt and a platinum salt, and the addition amount is from 10 ^-8 to 10 ^-3 per mol of silver halide. It is a mole. The crystal form of silver halide is not particularly limited, and may be cubic or tetradecahedral grains, or core-shell type or tabular grains. The silver halide crystal may be a monodisperse or polydisperse crystal,
The average particle size is in the range of 0.2 to 0.8 μm. One preferable example is a monodisperse or polydisperse crystal containing 70 mol% or more of silver chloride containing a rhodium salt or an iridium salt.

The silver halide emulsion can be sensitized in various ways as it is manufactured or coated. It is preferable to chemically sensitize by methods well known in the art, for example, with sodium thiosulfate, alkyl thiourea, or with a gold compound such as gold rhodanide, gold chloride, or a combination of both. The silver halide emulsions can also be sensitized or desensitized positively or negatively with dyes such as cyanines, merocyanines. There is no particular limitation on the wavelength range that can be sensitized or desensitized. Therefore, ortho sensitization, panchromatic sensitization, helium-neon laser sensitization, argon laser sensitization, LED sensitization, semiconductor laser sensitization can be performed, and UV sensitization and visible light desensitization for bright rooms. I can feel it.

The surface layer existing on top of the emulsion layer contains physical development nuclei. Physical development nuclei include fine particles of metal colloid such as silver, antimony, bismuth, cadmium, cobalt, lead, nickel, palladium, rhodium, gold and platinum, and sulfides, polysulfides, selenides of these metals, or those. It may be a mixture or a mixed crystal. The physical development core may or may not contain a hydrophilic binder, but gelatin, starch, dialdehyde starch, carboxymethyl cellulose, gum arabic, sodium alginate, hydroxyethyl cellulose, polystyrene sulfonic acid, vinyl imidazole and acrylamide A polymer, a hydrophilic polymer such as polyvinyl alcohol, or an oligomer thereof can be contained, and the content thereof is preferably 0.5 g / m ² or less. Further, the physical development nucleus layer may contain a developing agent such as hydroquinone, methylhydroquinone and catechol, and a known hardener such as formalin and dichloro-s-triazine.

In each coating layer such as an antihalation layer, a silver halide emulsion layer and a physical development nucleus layer, as a coating aid,
It may contain some of anionic, cationic or neutral surfactants, and may contain antifoggants, matting agents, thickeners, antistatic agents and the like.

The support for the lithographic printing plate of the present invention includes:
Paper or a synthetic or semi-synthetic polymer film, a metal plate such as aluminum or iron, and the like can be used as long as they can withstand lithographic printing. The surface of the support may be coated on one side or both sides with one or more polymer films or metal thin films. The surface of these supports can be surface-treated in order to improve the adhesion with the coating layer.

Particularly preferably used supports are paper having both surfaces or one surface coated with a polyolefin polymer, a polyester film, a polyester film having a hydrophilic surface, a surface-treated aluminum plate, and the like.
These supports may contain pigments for preventing halation and solid fine particles for improving surface properties. The support may also be light transmissive so that backside exposure is possible.

The developing solution used in the present invention contains an alkaline substance such as sodium hydroxide or potassium hydroxide,
Lithium hydroxide, sodium triphosphate, etc., sulfites as preservatives, silver halide solvents, such as thiosulfates,
Thiocyanates, cyclic imides, 2-mercaptobenzoic acid, amines, thickeners such as hydroxyethyl cellulose, carboxymethyl cellulose, antifoggants,
For example, potassium bromide, the compounds described in JP-A-47-26201, developers such as hydroquinones, catechol, 1-phenyl-3-pyrazolidone, development modifiers such as polyoxyalkylene compounds and onium compounds. Can be included. Further, compounds such as those described in U.S. Pat. No. 3,776,728, which improve ink transfer of the surface silver layer, can be used in the developing solution.

The surface silver layer after development of the lithographic printing plate of the present invention can be converted into ink receptivity or the receptivity can be enhanced with any known surface treatment agent. Examples of such a treatment liquid include Japanese Patent Publication No. 48-29723, US Pat.
721,559 and the like. The printing method, or the desensitizing liquid, the dampening liquid, or the like to be used may be a commonly known method.

[0032]

EXAMPLES The present invention will be explained below with reference to examples, but of course the present invention is not limited thereto.

Example 1 A 135 g / m ² double-sided polyethylene-coated paper was provided on one side with a matting layer containing silica particles having an average particle size of 3.5 μ (Coulter counter method), and the opposite side was subjected to corona discharge machining. , Carbon black, and average particle size 3.5
.mu. silica powder (Fuji Divison SY445) 0.
Anti-halation layer containing 6 g / m ² (gelatin 3.5 g
1.0 g / and m ^2), high sensitivity silver chloride emulsion is ortho sensitized with an upper 1-phenyl-3-pyrazolidone 0.1 g / m ² thereof (including gelatin 0.8 g / m ²⁾ as silver nitrate Two layers were simultaneously coated so that the coating amount would be / m ² .

As a hardener, 2,4-dichloro-6-
The antihalation layer contained 170 mg / m ^{2 of} sodium hydroxy-s-triazine, and the emulsion layer contained 80 mg / m ² of N-methylolethylene urea. After drying, the core coating solution described in Example 2 of JP-A-53-21602 (containing a copolymer of No. 3 acrylamide and imidazole as a polymer and hydroquinone as a developing agent at a ratio of 0.8 g / m ²⁾ was used. In Japanese Patent Laid-Open No. 4-2777
2 mg / m ² of pullulan of 47 was applied and dried to prepare a lithographic printing plate as Comparative Example A of the present invention.

A lithographic printing plate as an example of the present invention is a synthetic mica micromica manufactured by Corp Chemical Co., Ltd., MK, instead of the silica powder of the antihalation layer used in the lithographic printing plate (Comparative Example A). -100, MK-2
00 (aspect ratio 20 to 30) and iron-made chemical flow beads CL-4080-F (aspect ratio 10 to 20) at 0.6, 1.2 and 1.8 g / m ² , respectively. The planographic printing plates B to J were prepared and summarized in Table 1.

Immediately after the production of these 10 kinds of lithographic printing plates and after storing them for 5 days under the conditions of 50 ° C. and 80% relative humidity, image exposure was carried out by a plate making camera having an image reversing mechanism, and the following silver complex salt was used. 1 at 30 ° C with diffusion transfer developer
Development processing was performed for a minute.

<Transfer developer> 700 ml of water 20 g of potassium hydroxide 50 g of anhydrous sodium sulfite 50 g 2-mercaptobenzoic acid 1.5 g 2-methylaminoethanol 15 g Water is added to make 1 liter. After development processing, the original plate
Pass through a book squeezing roller to remove excess developer, and immediately treat with a neutralizing solution having the following composition at 25 ° C. for 20 seconds,
Excess liquid was removed with a squeezing roller, and dried at room temperature.

<Neutralization liquid> Water 600 ml Citric acid 10 g Sodium citrate 35 g Colloidal silica (20% liquid) 5 ml Ethylene glycol 5 ml Water is added to make 1 liter. The lithographic printing plate prepared by the above operation was mounted on an offset printing machine, the following desensitizing liquid was applied all over the plate surface, and printing was performed using the following dampening liquid.

<Desensitizing Solution> Water 600 ml Isopropyl alcohol 400 ml Ethylene glycol 50 g 3-Mercapto-4-acetamido-5-n-heptyl-1,2,4-triazole 1 g

<Humidifying liquid> o-phosphoric acid 10 g nickel nitrate 5 g sodium nitrite 5 g ethylene glycol 100 g colloidal silica (20% liquid) 28 g Water is added to make 2 liters.

As the printing machine, Ryobi 3200CD (trademark of Ryobi KK offset printing machine) was used, and the image was skipped due to the background stain of the non-image area and the missing of the silver image area, and the printing could not be performed. The number of printed sheets at that time was used for the judgment according to the following evaluation criteria. The ink is ABdick3-1012.
It was used. ○ 10,000 to 20,000 sheets △ 5,000 to 10,000 sheets × 2,000 to 5,000 sheets The printing results are shown in Table 2.

On the other hand, in order to see the water retention (background stain) of the non-image area, the ink is F Gloss Purple 68N made by Dainippon Ink.
Using the Eu-3,1% liquid (fountain water for PS plate / Etching liquid made by Fuji Film) as the dampening liquid, and using the Ryobi 3200CD as the printing machine The number of printed sheets at the time of rolling was judged according to the following evaluation criteria. ◎ 5000 sheets or more ○ 1000 to 5000 sheets △ 300 to 1000 sheets × 1 to 300 sheets The printing results are shown in Table 2.

[0043]

[Table 1]

In the above evaluation of printing durability, the image quality of the printed matter was simultaneously evaluated by the following evaluation method. In the image quality evaluation, how the halftone dots of 100 lines and 50% made by the camera plate can be reproduced on the printed matter was judged by the following evaluation criteria. ◎ Reproduce halftone dots with clear contours. ○ The contour becomes a half-tone dot. △ The contour becomes a halftone dot. × Each halftone dot becomes amorphous. The printing results are shown in Table 2.

[0045]

[Table 2]

From the above results, it was confirmed that the use of the tabular matting agent of the present invention resulted in excellent printing characteristics, particularly water retention and printing image quality.

Example 2 The 135 g / m ² double-sided polyethylene coated paper used in Example 1 was replaced with a 175 micron thick polyester base and the antihalation layer carbon black had a transmission density of 0.3. Test-evaluated in the same manner as in Example 1 except that the back-baked planographic printing plate prepared as described above was used.
The results are shown in Table 3.

[0048]

[Table 3]

From the above results, it was confirmed that even in the back-baked lithographic printing plate, the use of the tabular matting agent of the present invention resulted in excellent printing characteristics, particularly excellent water retention and printing image quality.

[0050]

INDUSTRIAL APPLICABILITY According to the present invention, the water retention and print image quality of a lithographic printing plate to which the silver complex salt diffusion transfer method is applied are improved, and particularly when it is applied to a back-baked lithographic printing plate, the print image quality is further superior. It is possible to improve scratch resistance in development processing and the like.

Claims (1)

[Claims] 1. An antihalation layer and a silver halide emulsion layer in a lithographic printing material to which a silver complex salt diffusion transfer method having at least an antihalation layer, a silver halide emulsion layer and a physical development nucleus layer is applied on a support. A lithographic printing material comprising a flat matting agent in at least one layer thereof.