JP2000318332A - Manufacture of lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a lithographic printing plate which is a simple plate-making method without requiring an alkali developer, and in addition, by which a printing plate of an excellent picture quality wherein the identification property between an image section and a non-image section is sufficiently kept, can be made, and at the same time, provide a manufacturing method for a lithographic printing plate wherein a plate-making is possible while being directly fitted on a printing machine after a scanning exposure for a short period of time, without performing a developing treatment, the sensitivity is high, a highly precise picture drawing is possible, the printing durability is excellent, and a printing fouling on a printed surface is less as well. SOLUTION: An original plate for lithographic printing has a porous base plate wherein the surface layer is porous, and a light-heat converting substance is embedded. Also, on the original plate for the printing, an image is recorded by irradiation with a laser beam along an image, and the irradiated surface is brought into contact with a printing ink, and a printed surface wherein the image region accepts the ink is formed, and thus, the printing is performed by the lithographic printing method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of general printing, particularly to lithographic printing, and more particularly to a novel lithographic printing plate manufacturing method capable of easily producing a printing plate. Among them, the present invention relates to a method of manufacturing a lithographic printing plate which can perform image recording by scanning exposure based on a laser beam and can be mounted on a printing machine and printed without development.

[0002]

2. Description of the Related Art In general, a lithographic printing plate comprises an oleophilic image area for receiving ink during a printing process and a hydrophilic non-image area for receiving fountain solution. As such a lithographic printing plate precursor, a PS plate in which a lipophilic photosensitive resin layer is provided on a hydrophilic support has been widely used. As a plate making method, usually, after exposing through an image such as a lith film, a non-image portion is dissolved and removed with a developing solution, and a desired printing plate is obtained by this method.

[0003] The plate making process in the conventional PS plate requires an operation of dissolving and removing a non-image portion after exposure, and it is necessary to eliminate or simplify such additional wet processing. This is one problem that has been desired to be improved over the conventional technology. In particular, in recent years, the disposal of waste liquid discharged from wet processing has become a major concern of the entire industry due to consideration for the global environment, and the demand for improvement in this aspect has been further increased.

[0004] As one of the simple plate making methods responding to this demand, an image recording layer is used which enables the non-image portion of a printing plate to be removed in a normal printing process. And a method for obtaining a final printing plate has been proposed. The lithographic printing plate making method by such a method is called an on-press development method. Specific examples of the method include a method of using an image recording layer soluble in a fountain solution or an ink solvent, and a method of mechanically removing the image recording layer by contact with an impression cylinder or a blanket cylinder in a printing press. However, a major problem of the on-press development method is that, after the printing original plate is exposed, the image recording layer is not fixed, for example, until the printing plate is mounted.
It was necessary to take a time-consuming method, such as storing the original plate completely in a light-shielded state or under constant temperature conditions.

On the other hand, another trend in this field in recent years is that digitization technology for electronically processing, storing, and outputting image information using a computer has become widespread. In response to technology,
Various new image output methods have come into practical use. Along with this, a computer that carries digitized image information in high-convergent radiation such as laser light, scans and exposes the original plate with this light, and directly manufactures a printing plate without passing through a lith film. Attention has been focused on to-plate technology. Accordingly, obtaining an original plate for a printing plate adapted to this purpose has become an important technical problem. Therefore, simplification, drying, and non-processing of plate making operations are more and more desired than ever in view of both the above-mentioned environmental aspects and adaptation to digitization.

[0006] In response to this request, one of the non-processable printing plate making methods is a printing plate making method utilizing irradiation of zirconia ceramic with active light to make the irradiated portion hydrophilic. No. However, the light sensitivity of zirconia is low, and the discriminability between an image part and a non-image part is insufficient due to an insufficient light conversion effect from hydrophobic to hydrophilic.

Further, it has been found that the surface of titanium oxide becomes hydrophilic by irradiation with actinic light, and application of this phenomenon to a simple printing original plate has been proposed. Generally, a titanium oxide film is formed by a vacuum evaporation method, a chemical evaporation method, a sputtering method,
Film formation methods such as a gas phase method such as a CVD method, a liquid phase method such as a spin coating method and a dipping method, and a solid phase method using a thermal spraying method or a solid phase reaction are known, but conventionally known. Although the titanium oxide films obtained by these methods exhibit better image forming characteristics than the above-mentioned methods, it is desired to further improve the discrimination between the image area and the non-image.

As another method of manufacturing a printing plate by scanning exposure, which is easy to incorporate into digital technology, recently, solid-state lasers such as a semiconductor laser and a YAG laser have become available at low cost. Therefore, in particular,
Plate making methods that use these lasers as image recording means are promising. In the conventional plate-making method, image recording is performed by giving an imagewise exposure of the photosensitive original plate at low to medium illuminance and changing the image-like physical properties of the original plate surface by a photochemical reaction. In the method using density exposure, a large amount of light energy is intensively irradiated onto an exposure area during an instantaneous exposure time, the light energy is efficiently converted to heat energy, and the heat causes chemical change, phase change, Alternatively, a physical change such as a change in form or structure is caused, and the change is used for image recording. That is,
Image information is input by light energy such as laser light, and image recording is recorded by a reaction by heat energy. Usually, a recording method utilizing heat generated by such high power density exposure is called heat mode recording, and converting light energy into heat energy is called photothermal conversion.

A major advantage of the plate making method using the heat mode recording means is that the plate is not exposed to light having a normal illuminance level such as room illumination, and that an image recorded by high illuminance exposure does not require fixing. . In other words, if a heat mode photosensitive material is used for image recording, it is safe against room light before exposure, and it is not essential to fix an image after exposure. Therefore, for example, if an image recording layer that is insolubilized or solubilized by heat mode exposure is used, and a plate-making process of removing the exposed image recording layer imagewise to form a printing plate is performed by an on-press development method, development (non-image Part removal) enables a printing system in which the image is unaffected for some time after image exposure, even if exposed to room ambient light. Therefore, if heat mode recording is used, it is expected that a lithographic printing plate precursor that is desirable for an on-press development system can be obtained.

[0010] As one of the preferable methods for producing a lithographic printing plate based on heat mode recording, a hydrophobic image recording layer is provided on a hydrophilic substrate, and is subjected to heat mode exposure in the form of an image. A method has been proposed in which the dispersibility is changed and, if necessary, the non-image areas are removed by wet development. As an example of such an original plate, for example, Japanese Patent Publication No. 46-279
No. 19 discloses an original plate provided with a recording layer having a so-called positive action in which solubility is improved by heat, specifically a recording layer having a specific composition such as a saccharide or a melamine formaldehyde resin, on a hydrophilic support. A method for obtaining a printing plate by performing heat mode recording is disclosed.

However, none of the disclosed recording layers has sufficient heat sensitivity, so that the sensitivity to the heat mode scanning exposure is far insufficient. In addition, hydrophobic / hydrophilic discrimination before and after exposure, that is,
The small change in solubility was also a practical problem. If discrimination is poor, it is practically difficult to make an on-press development plate.

A stencil printing method in which a lipophilic metal or organic sulfur compound surface layer is provided on a hydrophilic lower layer, and the lipophilic layer is irradiated with an image-like laser beam to record an image in a heat mode. Are disclosed in JP-A-52-37104,
No. 197192 and JP-A-7-1848. These have the advantages of the above-described heat mode plate making and printing methods, respectively.
The sensitivity of the heat mode to the laser irradiation light is still insufficient, and it is desired to further increase the sensitivity and thereby enhance the effect of discriminating the image area from the non-image area.

Another conventional problem in the conventional heat mode positive printing plate is that it involves a defect called a residual film in a non-image portion. That is, in the heat mode positive type original plate, since the heat generation at the time of the heat mode exposure is based on the light absorption of the light absorbing substance in the recording layer, the amount of heat generated is large on the recording layer surface and is close to the support. Then it is often small. For this reason, the change in solubility due to exposure in the vicinity of the support of the recording layer is small, and the degree of hydrophilicity is reduced. As a result, in an exposed portion where a hydrophilic surface is to be provided, a hydrophobic film may often not be completely removed, resulting in a residual film. Such a residual film causes print stains on a printed matter, and therefore, improvement in that point is required.

The above-described plate making / printing method utilizing image recording by irradiation with actinic light and image recording in a heat mode includes:
In each case, a printing plate can be made directly from under the plate without the use of a film, and therefore, it is possible to make a plate on a machine, and it is possible to omit the development operation. It has weaknesses such as shortage and a difference in sensitivity between the surface and the bottom of the image recording layer. These weaknesses are basically defects caused by insufficient discrimination between the image portion and the non-image portion, and are also directly related to print quality and printing durability. Therefore, in plate making and printing methods that use either active light irradiation or heat mode light irradiation image recording, the basic measures to improve both print quality and printing durability are to improve discrimination. It can be said that the current situation.

[0015]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a simple plate making method which does not require an alkali developing solution, and which has excellent image quality in which the discrimination between an image area and a non-image area is sufficiently maintained. An object of the present invention is to provide a method for producing a lithographic printing plate capable of producing a plate. A further object of the present invention is to solve the above-mentioned deficiencies of the plate making method using laser exposure, that is, the plate making method is directly mounted on a printing press without performing a developing process after a short scanning exposure. It is an object of the present invention to provide a method for producing a lithographic printing plate having high sensitivity, high sensitivity, high-definition drawing, excellent printing durability, and less printing smear on a printing surface.

[0016]

Means for Solving the Problems In order to achieve the above object, the present inventor has focused on the characteristics of a porous material, and considered that it is necessary to have means for remarkably exhibiting the characteristics, and studied the means. By embedding a light-to-heat conversion substance in a porous substrate, the thermal response sensitivity to laser light is increased, and images can be formed by lower laser light irradiation, and high-definition drawing can be performed by reducing illuminance to enable high-definition drawing. The plate manufacturing method has been completed. That is, the present invention is as follows.

(1) A lithographic printing plate precursor having a porous substrate having a porous surface layer and a light-to-heat conversion material embedded therein is irradiated with laser light in an image-like manner to make the irradiated portion hydrophilic. Lithographic printing plate manufacturing method.

(2) The effect of the present invention becomes more remarkable because the surface layer of the porous substrate is anodized.

(3) The effect of the present invention is further enhanced by providing a lipophilic layer on the porous substrate in which the photothermal conversion material is embedded.

(4) Further, the porous substrate is a substrate obtained by anodizing at least one metal selected from aluminum and transition metals of Groups 4A to 6A of the periodic table, and a photothermographic material is formed on the surface layer of the substrate. The effect of the present invention becomes more remarkable even when the conversion material is embedded.

According to the present invention, a coating layer is scattered and removed or scratched by irradiating a laser beam to the surface of a porous substrate in which a photothermal conversion substance is embedded or a substrate having an oleophilic layer provided thereon. Based on having a lipophilic layer (lipophilic layer) that is capable of rubbing (also called ablation). A technique for forming a printing plate by providing an oleophilic layer on a metal support and irradiating a laser beam imagewise to record an image is known. Requests are not always enough. However, in the present invention, in the case of a porous substrate in which a photothermal conversion substance is embedded, or a porous substrate in which an oleophilic layer is provided on the substrate, the heat mode sensitivity of laser light irradiation to the surface is high, It was found that heat diffusion was small, high-definition image recording was possible, and printing durability was excellent. In particular, it has been found that when the surface layer of the porous substrate in which the light-to-heat conversion material is embedded is anodized, the effect is further enhanced.

Utilizing this characteristic, when the surface of the porous substrate having a lipophilic surface that normally accepts printing ink or the surface of a substrate having a lipophilic layer provided thereon is irradiated with image-like active light, The part irradiated with light causes destruction (ablation) due to heat, and the hydrophilic surface of the underlying metal compound film layer is exposed to form a region for receiving dampening water,
The lipophilic surface that has not been irradiated with light can form an ink receiving area to form the printing surface. Therefore, a printing plate that can be directly printed is completed, and there is no need to perform operations such as development processing. In other words, the lithographic printing original plate obtained in this manner can record images with sufficient sensitivity by scanning exposure based on laser light, and can be directly mounted on a printing machine without development and printed. They also have excellent printing durability and have been found to overcome the disadvantages of the prior art.

In the following description, 4 in the above periodic table
When the metal compounds of the Group A to Group 6A elements are collectively referred to, they may be referred to as “transition metal compounds according to the present invention”. Further, the `` active light '' that changes the surface from lipophilic to hydrophilic is high-intensity visible light or infrared light, preferably infrared light. This is probably due to the heat mode mechanism. In this respect, it is necessary to distinguish from active light that excites the surface of a so-called metal oxide having photocatalytic activity to make it hydrophilic. The latter is interpreted as that the irradiated light photochemically activates surface electrons, and is not a heat mode operation. The light acting as active light is ultraviolet light or visible light having a relatively short wavelength, which is different from visible light or infrared light preferably having a long wavelength, which is preferably used in the present invention. In the present invention, the former, that is, the light beam active in the heat mode is referred to as “active light”.

[0024]

Embodiments of the present invention will be described below in detail. [Porous substrate according to the present invention] The porous substrate of the present invention, originally, the substrate itself may be a porous substrate,
The surface of a substrate that is not originally porous may be covered with a porous material. Hereinafter, the substrate, the porous material, the method of forming the porous substrate, the light heat exchange material, and the means for embedding the light heat exchange material in the porous material used in the present invention will be described.

[Substrate] As the substrate, stainless steel, A
l, Cr, Ge, ITO, (tin-doped In ₂ O
₃ ), Zn, O, Ni, Nichrome, Ti, Si, SiO
Substrates having a surface made of a metal or oxide such as ₂ can be used. Further, a metal or metal oxide is deposited on the substrate,
A substrate provided in a thin film shape by sputtering, lamination, or the like can also be used. In the present invention, the carrier of the image recording layer provided on the support is called a substrate, but the support and the substrate may be integrated.

(Porous Material) As the porous material used for the porous substrate of the present invention, the substrate itself may be a porous substrate, or the surface of a substrate that is not originally porous may be a porous material. It may be a porous material provided by coating. The porous material is not particularly limited as long as it has an average pore diameter of 10 ° to 10 μm, but it is preferable to use a metal compound. As a specific example, for example,
Aluminum oxide, silicon oxide, zinc oxide, yttrium oxide, titanium oxide, zirconium oxide, hafnium oxide, panadium oxide, niobium oxide, tantalum oxide, molybdenum oxide, tungsten oxide, chromium oxide, tin oxide, silicon nitride, aluminum nitride, Boron nitride,
Examples include titanium nitride, zirconium nitride, hafnium nitride, panadium nitride, niobium nitride, tantalum nitride, molybdenum nitride, tungsten nitride, chromium nitride, and the like. Further, titanium silicide, zirconium silicide, hafnium silicide, panadium silicide, niobium silicide, tantalum silicide, molybdenum silicide, tungsten silicide, chromium silicide, and the like can be given. Titanium boride, zirconium boride, hafnium boride, panadium boride, niobium boride, tantalum boride, molybdenum boride, tungsten boride, chromium boride, and the like. In addition, silicon carbide, titanium carbide, boron carbide, zirconium carbide, hafnium carbide, panadium carbide, niobium carbide, tantalum carbide, molybdenum carbide, tungsten carbide, chromium carbide, and the like can be given. Further, a mixture may be used instead of a single substance. For example, a sialon made of silicon, aluminum, oxygen, and nitrogen can be used. Further, examples thereof include lead titanate, lead zirconate, lead zirconate titanate, lead lanthanum zirconate titanate, mullite, ferrite, barium titanate, strontium titanate, and boron nitride-aluminum nitride. Those not mentioned here can be used as long as they are porous. Among them, aluminum and 4A of the periodic table
Compounds of Group A to Group 6A metal elements are preferred. The metals of Groups 4A to 6A of the Periodic Table generally refer to titanium, zirconium, hafnium, panadium, niobium, tantalum, molybdenum, tungsten, and chromium.

The porous substrate can be formed by anodic oxidation, C
VD, sol-gel, sputtering, ion plating, diffusion, thermal spraying, and the like can be used as appropriate. As a thermal spraying method, a method such as flame radiation, arc radiation, and plasma thermal spraying is used, but the method is not limited to a specific method. Among them, an anodic oxide film is particularly preferable because it has a high adsorptivity to an organic or inorganic substance or dye and is suitable for embedding a photothermal conversion substance. The thickness is desirably 0.01 μm to 10 μm, preferably 0.05 to 5 μm. More preferably, it is 0.2 to 3 μm. In order to sufficiently exert the effect of the irradiation light, it is convenient that the thickness is 0.01 μm or more.

(Anodic Oxidation Method) The anodizing treatment of the surface of the substrate according to the present invention is performed in the following aqueous electrolyte solution. (1) An aqueous solution containing at least one selected from inorganic acids such as sulfuric acid, phosphoric acid, nitric acid, and boric acid. (2) A mixed aqueous solution further containing hydrogen peroxide in addition to the inorganic acid. (3) A mixed aqueous solution further containing at least one of an alkali metal salt and an alkaline earth metal salt thereof in addition to the inorganic acid of (1). (4) An aqueous solution containing at least one ammonium salt of an inorganic acid of the above (1) or a solution using a mixed solution of ethylene glycol and water as a solvent. (5) An aqueous solution containing at least one selected from organic acids such as oxalic acid, tartaric acid, citric acid, acetic acid, lactic acid, succinic acid, glutamic acid, sulfosalicylic acid, and naphthalenedisulfonic acid. (6) An aqueous solution containing one or more of the alkali metal salts and alkaline earth metal salts of the above organic acids. (7) An aqueous solution containing at least one ammonium salt of the organic acid of the above (5) or a solution using a mixed solution of ethylene glycol and water as a solvent. (8) An aqueous solution containing one or more selected from hydroxides of Na, K, Ca, Li and Mg, water-soluble carbon salts, and alkaline aqueous solutions such as ammonium hydroxide. (9) An aqueous solution containing at least one of glycerophosphoric acid, its alkali metal salt and an alkaline earth metal salt, and more preferably at least one of acetic acid, its alkali metal salt and its alkaline earth metal salt. (10) An aqueous solution containing a combination of the above solution components (1) to (9).

The concentration of the above-mentioned aqueous electrolyte solution is appropriately determined depending on the type of the electrolyte, and various conditions are selected for the anodizing treatment depending on the selected aqueous electrolyte solution. The concentration is 0.001-3mol /
L, preferably 0.005 to 1 mol / L, liquid temperature is 5 to 70
° C, preferably 20 to 50 ° C, current density 1 to 60 A / d
m ² , preferably ² to 10 A / dm ² , voltage 1 to 500 V, preferably 100 to 400 V, and electrolysis time 10 seconds to 10 minutes, preferably 1 to 5 minutes. Suitable anodizing conditions for each representative aqueous electrolyte solution are given in the examples. The thickness of the anodized film is about 0.001 to 10 microns, preferably 0.1 to 5.0 microns, and particularly preferably 0.3 to 1.0 microns.

In some cases, it is effective to dope a certain metal on the anodized surface, for example, for heat diffusion. For this purpose, doping of a metal having a low ionization tendency is suitable. , Au, Ag, C
It is preferable to dope u, Ni, Fe, and Co.
Further, a plurality of these preferable metals may be doped.

(Pretreatment of Anodizing) The transition metal plate according to the present invention includes a metal plate having a single structure and a metal plate reinforced with a support, and is subjected to a surface roughening treatment prior to anodization. May be applied. Water retention when the surface is made hydrophilic by roughening can be enhanced, and therefore, the distinction between an image and a non-image portion can be improved. In the case of performing the surface roughening treatment, if necessary, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution, or the like for removing rolling oil on the surface is performed prior to the surface roughening treatment.

The surface roughening treatment of the metal plate (thin layer) is performed by various methods. For example, a method of mechanically roughening the surface, a method of electrochemically dissolving and roughening the surface, and This is performed by any of the methods for chemically selectively dissolving the surface or a combination thereof. As a mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, and a buff polishing method can be used. The electrochemical surface roughening method also employs a method known as a method of surface roughening of an aluminum metal surface, for example, a method of performing alternating or direct current in a hydrochloric acid or nitric acid electrolytic solution, to apply a roughening method to the transition metal surface. be able to. Also, Japanese Patent Application Laid-Open
A method in which the two are combined as disclosed in JP-A-63902 can also be used. Further, the chemical surface roughening treatment is performed by immersing the metal surface in an aqueous solution of a mixture of alkaline salts selected from sodium hydroxide, sodium carbonate, sodium silicate, sodium pyrophosphate and the like to etch the metal surface.

[Light-to-Heat Conversion Material] The light-to-heat conversion material is not particularly limited as long as it absorbs light, converts it into heat, and emits it. A dye capable of effectively absorbing the wavelength of light in the wavelength region from ultraviolet to near infrared and efficiently converting it to heat energy is preferably used. In a particularly preferred embodiment of the present invention, heat is generated by irradiation with a semiconductor laser beam.
Near-infrared absorbers which show an absorption maximum at 00 nm and have no or small absorption in the visible region are preferred.

As a specific example of the near-infrared absorbing agent when an infrared laser is used, a dye is exemplified. Preferred dyes are dyes and pigments having a property of absorbing infrared rays and converting them into heat energy. Preferred pigments and dyes, particularly pigments, include cyanine dyes, squarylium dyes, methine dyes, naphthoquinone dyes, quinone imine dyes, quinone diimine dyes, quinone diimine dyes, pyrylium salt dyes, naphthoquinone dyes, phthalocyanine dyes, and naphtho. Examples include a rosinine dye, a dithiol metal complex dye, an anthraquinone dye, an azo dye, a trisazo dye, a porphyrin pigment, a morpholine pigment, and a phthalocyanine pigment.

Specific examples of preferable pigments and dyes include cobalt green (CI. 77335), emerald green (CI. 77410) and phthalocyanine blue.
(CI. 74100), copper phthalocyanine (CI.
74160), Ultramarine (CI. 7700)
7), navy blue (CI. 77510), cobalt purple (C.I.
I. 77360), Pariogen Red 310 (CI.7)
1155), permanent red BL (CI.711)
37), perylene red (C.I. 71140), rhodamine lake B (C.I. 45170: 2), Helio Bordeaux BL (C.I. 14830), light fast red toner R (C.I. 12455), First Scarlet VD, Resol First Scarlet G
(CI. 12315), permanent brown FG
(CI. 12480), indanthrene brilliant orange RK (CI. 59300), and red-mouthed graphite (C.I.
I. 77601), Hansa Yellow 10G (CI.1)
1710), titanium yellow (C.I.77738),
Zinc yellow (C.I. 77955), chrome yellow (C.I.
I. 77600), and various pigments used in electrostatic recording toners can also be preferably used. In addition, malachite green oxalic acid, quinizarin, 2- (α-naphthyl) -5-phenyloxazole, oil pink # 312, oil green BG, oil blue BOS, oil black BY, oil black BS, oil black T-505 (or more) Basic Fuchsin, m-cresol purple, cyano-p-diethylaminophenylacetanilide, or dyes described in JP-A-62-293247 and Japanese Patent Application No. 7-335145. Can be mentioned. Above all, phthalocyanine complex salts of copper, cobalt, nickel, iron such as phthalocyanine green and phthalocyanine blue, 3,3′-ethylmesoethylnaphthia (oxa) dicarbocyanine, 3,3 ′
Preferred are dicarbocyanine and tricarbocyanine dyes represented by -ethylnaphthothia (oxa) tricarbocyanine.

As the inorganic pigment, for example, carbon black, titanium dioxide, zinc oxide, Prussian blue, cadmium sulfide, iron oxide, and chromates of lead, zinc, barium and calcium can be suitably used. Also, ceramic fine particles such as oxides, nitrides, silicides, borides, and carbides can be filled. Titanium oxide, zirconium oxide, hafnium oxide,
Panadium oxide, niobium oxide, tantalum oxide, molybdenum oxide, tungsten oxide, chromium oxide, and the like can be given. Further, titanium nitride, zirconium nitride, hafnium nitride, panadium nitride, niobium nitride, tantalum nitride, molybdenum nitride, tungsten nitride, chromium nitride, and the like can be given. Further, titanium silicide, zirconium silicide, hafnium silicide, panadium silicide, niobium silicide, tantalum silicide, molybdenum silicide, tungsten silicide, chromium silicide, and the like can be given. Titanium boride, zirconium boride, hafnium boride, panadium boride, niobium boride, tantalum boride, molybdenum boride, tungsten boride, chromium boride, and the like. Further, titanium carbide, zirconium carbide, hafnium carbide, panadium carbide, niobium carbide, tantalum carbide, molybdenum carbide, tungsten carbide, chromium carbide, and the like can be given. Further, a mixture may be used instead of a single substance. As the dye, an acid paint, a direct dye, a disperse dye, an oil-soluble dye, a metal-containing oil-soluble dye and the like can be suitably used.

(Means for Embedding Light-to-Heat Conversion Substance) As a means for embedding the light-to-heat conversion substance in the porous material, a method of processing with an alternating current, so-called electrolytic coloring, Alternatively, a method in which a porous material is immersed in a dispersion liquid to cause the porous material to be adsorbed on a porous surface, that is, a so-called dyeing method can be used.

Next, the electrolytic coloring method will be described. In the electrolytic coloring method, it is well known that anodized aluminum or an aluminum alloy is subjected to alternating current electrolysis in an electrolytic solution to fill the anodized hole with a metal oxide or a metal hydroxide. The method of the present invention is described in more detail as follows. First, a porous material or a substrate coated with the porous material is immersed in an electrolytic solution in which a photothermal conversion substance is dissolved, and this is used as an anode, and an alternating current is applied. The AC voltage is 5 to 50 V, preferably 10 to 30 V.
In the present invention, there are various metal salts used in the electrolytic solution. For example, nickel, cobalt, chromium, copper, magnesium, iron, cadmium, titanium, manganese, molybdenum, calcium, panadium,
Nitrates, sulfates, phosphates of metals such as tin, lead and zinc,
There are inorganic acid salts such as hydrochloride and chromate, and organic acid salts such as oxalate, acetate and tartaric acid. In order to increase the degree of coloring, three or more metal salts among these are used. Alternatively, electrolysis containing a mixture of two or more metal salts and a strongly reducing compound is used. This increases flexibility. The concentration of these metal salts is 5 to 500 g in total.
/ Liter, preferably 10 to 250 g / liter. Examples of the strong reducing compound used in the present invention include dithionites such as sodium dithionite and zinc dithionite, ammonium thiosulfate, sodium thiosulfate, potassium thiosulfate and iron thiosulfate. Bisulfites such as thiosulfate, sodium bisulfite and potassium bisulfite; sulfites such as sulfite, ammonium sulfite, sodium sulfite, and potassium sulfite; thioglycolic acid, ammonium thioglycolate, sodium thioglycolate, and potassium thioglycolate And thioglycolates such as lithium thioglycolate. They are used at a concentration of 0.05 to 10 g / l, preferably 0.5 to 3 g / l.

The above-mentioned electrolyte solution usually contains an inorganic acid such as sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, boric acid, thiocyanic acid, chromic acid or the like, oxalic acid, acetic acid, propionic acid, formic acid, tartaric acid, and apple. Organic acids such as acids, or at least one of ammonium salts, amino salts or imino salts thereof are added. The added concentration is 5 to 2
50 g / l. In addition, in the AC colored electrolysis, the power is further improved by performing the electrolysis while changing the voltage to a voltage lower than the initial applied voltage. The voltage difference to be changed is preferably 1 to 10 V, and the time to be changed is usually within 2 minutes after the energization, and preferably for 5 to 60 seconds. Further, the above-mentioned photothermal conversion substance may be added to the above-mentioned electrolyte solution.

The film electrolytically colored by the above method is subjected to a sealing treatment by a known means such as boiling water, chemical sealing or pressurized steam, if necessary. After the sealing treatment, or without the sealing treatment, the surface may be protected by dip coating or electrodeposition coating with a resin paint if necessary. Further, a method of adsorbing an organic dye or an inorganic compound (dyeing method) or the like can be used. In the dyeing method, the above-mentioned organic dye or inorganic compound of the light-to-heat conversion substance is used by dissolving it in a solvent or dispersing it in fine particles. This is a method in which a porous material is immersed in the solution to be adsorbed on the porous surface. The solvent may be any as long as it can dissolve the light-to-heat conversion substance, but water is particularly preferred.

[Lipophilic layer] The lipophilic layer used in the lithographic printing plate precursor of the present invention may be a layer made of any substance as long as it can be scattered by laser beam irradiation, ie, can be ablated, and is lipophilic. For example, a lipophilic metal or a lipophilic polymer can be used as a constituent material of the layer. Preferred lipophilic layers are described below.

When the lipophilic layer is a metal thin film layer, the metal is preferably a transition metal, indium, tin, antimony, thallium, tellurium, lead, bismuth, aluminum, potassium, germanium, tellurium, or an alloy thereof. The transition metal is any transition metal such as scandium to zinc having an atomic number of 21 to 30, yttrium to cadmium having an atomic number of 39 to 48, hafnium to mercury having an atomic number of 72 to 80, and a lanthanoid rare earth metal having an atomic number of 57 to 71. Can be used.
In general, zinc, cadmium, and mercury have many structures that can take an electron shell, so they may or may not be included in the transition metal.In the present invention, however, these elements also exhibit the effects of the present invention. Is included. Among them, titanium, zinc, iron, cobalt, nickel, copper, tin, tellurium,
Indium, vanadium and bismuth are preferred. Especially 5
Tin, tellurium, bismuth, and zinc having a melting point of 00 ° C. or less are desirable. The thickness of the metal layer is desirably 100 A to 1 μm. Among them, 500A to 5000A is particularly desirable.

As the lipophilic layer other than metal, a layer containing (1) a resin that is lipophilic and thermoplastic and (2) a substance that converts laser beam light into heat may be provided. Polyethylene as a lipophilic and thermoplastic resin,
Polypropylene, polyester, polyamide, acrylic resin, vinyl chloride resin, vinylidene chloride resin, polyvinyl butyral resin, nitrocellulose, polyacrylate, polymethacrylate, polycarbonate, polyurethane, polystyrene, vinyl chloride resin-vinyl acetate copolymer, vinyl chloride-acetic acid Vinyl-vinyl alcohol copolymer, vinyl chloride-resin vinyl-maleic acid copolymer,
Examples thereof include vinyl chloride-acrylate copolymer, polyvinylidene chloride, vinylidene chloride-acrylonitrile copolymer, and the like.

[Support] The printing original plate according to the present invention can be used in various forms with respect to the support. Particularly preferred is a single configuration of a metal plate whose surface is anodized using the substrate itself as a support. In that case, the thickness of the metal plate is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, and particularly preferably 0.2 mm to 0.3 mm.

Further, the metal is made of a low-cost metal plate that can be made into a thin plate (thin layer) and reinforced in terms of strength, or a metal plate with high flexibility (flexible) without using the metal as a support. May be provided with a metal plate on the surface thereof, and the surface may be anodized. A preferred metal plate having high strength and low cost or high flexibility is a metal plate made of, for example, aluminum, stainless steel, nickel, or copper.
The support metal plate and the metal plate may be bonded to each other, or a metal may be vacuum-deposited on a thin layer on the metal plate. The former is more economical and simpler. Less than,
In the description of the present specification, when the support is a metal, the support may be referred to as a substrate in accordance with the common practice in the art, but with respect to the metal, the support and the substrate are synonymous.

In addition, a thin metal layer can be provided on a plastic support such as polyester or cellulose ester which is chemically stable and sufficiently flexible.
Further, a metal layer may be provided on a support such as waterproof paper, polyethylene laminated paper, or impregnated paper.

The plastic and paper support preferably used include, for example, paper laminated with polyethylene, polypropylene or polystyrene, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate,
Examples include plastic films such as polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, and polyvinyl acetal; paper on which aluminum is laminated or vapor-deposited; and plastic films.

Among the above-mentioned preferred supports, a polyester film, aluminum or a SUS plate which is hardly corroded on a printing plate, and among them, an aluminum plate which has good dimensional stability and is relatively inexpensive is particularly preferable. Suitable aluminum plates are a pure aluminum plate and an alloy plate containing aluminum as a main component and containing a trace amount of a different element, and may be a plastic film on which aluminum is laminated or vapor-deposited. The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of the foreign element in the alloy is at most 10% by weight or less. Aluminum which is particularly preferred in the present invention is pure aluminum. However, completely pure aluminum is difficult to produce due to refining technology, and therefore may contain a slightly different element. As described above, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate of a conventionally known and used material can be appropriately used.

When using an anodized substrate as the support, the metal support may be roughened by a known method. The surface roughening may be performed by any of mechanical means, electrochemical means, and chemical etching means, or may be performed in combination. Roughening may improve the water retention of the anodized transition metal film provided thereon. The preferred roughened metal support is an aluminum support.

When a metal support is provided separately from the substrate, the thickness of the support used is about 0.06 mm to 0.6 mm, preferably 0.1 mm to 0.4 mm, particularly preferably 0.1 mm to 0.4 mm. 3 mm, and the thickness of the thin layer of the transition metal is
About 0.001 mm to 0.1 mm, preferably 0.005 mm
~ 0.05mm, particularly preferably 0.01mm ~ 0.05mm
It is.

[Plate Making] The surface of a printing plate having a lipophilic layer formed on a porous substrate in which the photothermal conversion substance of the present invention is embedded is inherently lipophilic and accepts ink, but is activated by active light. When the image exposure is performed, the part irradiated with light causes an ablation, and the part of the surface of the underlying anodized transition metal layer also exposed to light becomes hydrophilic,
Stop accepting ink. Thus, the image-exposed printing plate is brought into contact with the lithographic printing ink so that the non-image areas retain the dampening solution, the image areas form a printing surface that has received the ink, and the printing surface contacts the printing surface. Printing is performed by transferring the ink.

(Light Irradiation) In the present invention, the active light for exciting the metal film on the surface of the porous substrate in which the photothermal conversion material is embedded or the lithophilic layer on which the lipophilic layer is formed is exposed to light of the film. Light from any light source may be used as long as the light is within the range. For example, titanium oxide has an anatase type of 3
The rutile type has a photosensitive area of 413 nm or less, and the anodized titanium film has a photosensitive area of 420 nm or less.
Light having a photosensitive area below m can be used. As a preferable light source, a mercury lamp, a tungsten halogen lamp, another metal halide lamp, a xenon lamp, a carbon arc lamp, or the like can be used. A helium cadmium laser having an excitation light wavelength of 325 nm or a water-cooled argon laser having an oscillation wavelength of 351.1 to 363.8 nm can also be used. Further, a zinc sulfide laser having an oscillation wavelength of 330 nm, a zinc sulfide laser having an oscillation wavelength of 370 nm, and a zinc sulfide / cadmium laser having an oscillation wavelength of 330 to 440 nm, for which near-ultraviolet laser oscillation has been confirmed, can also be applied. Further, an Nd: YAG laser having a wavelength of 1064 nm can be used. In particular, a Nd: YAG laser equipped with a Q-switch and engineered with a krypton mark lamp by pulsed oscillation is preferred. When an image is formed on an anodized titanium film, the peak output is 1000
It is preferable to irradiate a laser beam of w, preferably 2000 w. In addition, GaAs, GaP, PbS, Pb
Semiconductor laser such as Se, ArF, KrF, xEc
Excimer lasers such as L and XeF and helium neon lasers can also be used.

The preferred intensity of the irradiation light varies depending on the wavelength of the light, but is usually 0.05 to 100 joule / cm ² , preferably 0.2 to 100 as the surface exposure intensity before being modulated with the image to be printed. It is 10 joule / cm ² , more preferably 0.5 to 5 joule / cm ² .

In the case where the image exposure is a particularly intense irradiation called scattering or removal of the image layer, which is called ablation, a laser light source containing a large amount of infrared components is used to modulate the laser beam with an image to obtain an original plate. Although it is preferable to perform a method of scanning the upper side, photothermal conversion is performed even with a visible light laser as long as the radiation is efficiently absorbed by the light absorbing substance. Examples of the laser light source include a semiconductor laser, a helium neon laser, a helium cadmium laser, and a YAG laser. Irradiation can be performed with a laser having a laser output of 0.1 to 300 W. When a pulse laser is used, it is preferable to irradiate a laser having a peak output of 1000 W, preferably 2000 W. In this case, the exposure amount is preferably in the range of 0.1 to 10 J / cm ² , and more preferably in the range of 0.3 to 1 J / cm ² , before the surface exposure intensity is modulated in the print image. preferable.

The above photosensitivity is different from the photosensitivity of the zirconia ceramic (Japanese Patent Application Laid-Open No. 9-169098) described above as the prior art. For example, the sensitivity is described as a laser beam of 7 W / μm ² for zirconia ceramics, and the sensitivity of the anodized titanium film is 70 joule / cm ^{2 when} the pulse duration of the laser beam is 100 nanoseconds. One order of magnitude lower. Similarly, a surface layer of a lipophilic metal or an organic sulfur compound is provided on the hydrophilic lower layer described above as a conventional technique, and the lipophilic layer is irradiated with an image-like laser beam to form an image in a heat mode. JP-A-52-37104 for performing recording,
The heat mode sensitivity to laser irradiation light is high for plate making printing methods such as those disclosed in JP-A-197192 and JP-A-7-1848, and this enhances discrimination between an image portion and a non-image portion. .

[Printing Step] After the image printing exposure is performed on the surface of the porous substrate in which the photothermal conversion substance of the present invention is embedded or the lipophilic layer is formed thereon, the printing original plate is developed. It can be sent directly to the lithographic printing process without any processing. Therefore, it has many advantages, mainly simplicity, as compared with the known lithographic printing method. That is, as described above, the chemical treatment with the alkaline developer is unnecessary, and the accompanying wiping and brushing operations are not required, and further, there is no environmental load due to the discharge of the waste developer.

The exposed portions of the lithographic printing plate obtained as described above are sufficiently hydrophilic, but may optionally contain washing water, a rinsing solution containing a surfactant, etc., gum arabic and starch derivatives. It is post-treated with a desensitizing solution. As the post-processing when the image recording material of the present invention is used as a printing plate material, these processings can be used in various combinations. As the method, a method of applying the printing solution on a lithographic printing plate with a sponge or absorbent cotton impregnated with the surface conditioning solution, or immersing the printing plate in a vat filled with the surface conditioning solution, Application by an automatic coater or the like is applied. Further, it is more preferable that the application amount is made uniform by using a squeegee or a squeegee roller after the application. The application amount of the surface conditioning liquid is generally 0.03 to
0.8 g / m ² (dry weight) is appropriate. The lithographic printing plate obtained by such processing is applied to a lithographic printing machine or the like,
Used for printing many sheets.

[0058]

[Examples 1 to 7 and Comparative Examples 1 to 5]

(Example 1) In Example 1, a commercially available titanium plate having a thickness of 0.2 mm was replaced with sodium glycerophosphate 0.005 m.
ol / L and 0.09 mol / L of strontium acetate were used, anodized by direct current at a temperature of 40 ° C. and a current density of 5 A / dm ² for 4 minutes, washed with water and dried to prepare a substrate [A]. . Next, bath temperature 25 ° C, stannous sulfate 10 g / L,
AC electrolysis was performed for 60 seconds in a 40 g / L sulfuric acid electrolyte at a current density of 0.8 A / dm ² . Thereafter, using a vacuum deposition apparatus manufactured by JEOL Ltd., a 1000 A-thick titanium metal was deposited on the substrate A to prepare a lithographic printing original plate [A-1]. This printing original plate [A-1] was irradiated with a YAG laser under the following conditions.

Laser power: 0.7 W Beam diameter: 45 μm Scanning speed: 1.2 m / sec

(Evaluation of printability) The above lithographic printing plate [A-1]
Was observed with an optical microscope, and a fine line of 35 μm could be drawn. The thicker the thin line, the higher the sensitivity. The lithographic printing plate on which an image was formed by laser irradiation in this way was printed on a printing machine without post-processing. A Harris chrysanthemum half-color machine (manufactured by Harris Co., Ltd.) was used as a printing machine, Geos Ink (manufactured by Dainippon Ink and Chemicals, Inc.) as ink, and a dampening water EU as dampening water.
-3 (manufactured by Fuji Photo Film Co., Ltd.) diluted 1: 100 with water, 90 vol% and isopropanol 10 vol
Printing was carried out on woodfree paper using the respective mixtures with 1%. As a result, no stain was found on the laser-irradiated portion, and on the non-irradiated portion, it was possible to print 10,000 clear inked prints.

(Example 2) In Example 2, the substrate [A] of Example 1 was heated at a bath temperature of 25 ° C, titanium sulfate of 40 g / L,
AC electrolysis was performed for 60 seconds in a 40 g / L sulfuric acid electrolyte at a current density of 0.8 A / dm ² . In the same manner as in Example 1, titanium metal was deposited by vacuum deposition to prepare a substrate [A-2]. Next, YAG laser irradiation was performed in the same manner as in Example 1. When the lithographic printing plate [A-2] was observed with an optical microscope in the same manner as in Example 1, a fine line of 35 μm could be drawn. In addition, 10,000 clear prints could be printed.

Example 3 In Example 3, the substrate [A] was immersed in a solution of 2 parts by weight of a naphthocyanine dye in tetrahydrofuran at 30 ° C. for 2 minutes and air-dried. In the same manner as in the above, titanium was deposited to prepare a substrate [A-3]. When the lithographic printing plate [A-3] was observed with an optical microscope in the same manner as in Example 1, a fine line of 35 μm could be drawn. In addition, 10,000 clear prints could be printed.

Example 4 In Example 4, commercially available 0.2 mm aluminum was anodized by direct current for 20 seconds at a temperature of 30 ° C. and a current density of 30 A / dm ² using 100 g / L of a sulfuric acid solution. After washing with water and drying, a substrate [B] was prepared. After immersing the substrate [B] in a solution of 3 parts by weight of titanium nitride dispersed in 40 parts by weight of MEK at 30 ° C. for 2 minutes,
It was dried in an oven at 100 ° C. for 1 minute. Next, chromium was deposited on the substrate [B] to form a substrate [B-1].
When the planographic printing plate [B-1] was observed with an optical microscope in the same manner as in Example 1, a fine line of 25 μm could be drawn.
In addition, 10,000 clear prints could be printed.

Example 5 In Example 5, a commercially available zirconium plate having a thickness of 0.2 mm was prepared by using a sulfuric acid solution of 100 g / L.
The substrate was anodized by direct current at a temperature of 30 ° C. and a current density of 5 A / dm ² for 90 seconds, washed with water and dried to prepare a substrate [C]. The substrate [C] was heated at a bath temperature of 25 ° C. and stannous sulfate 10 g /
L, 40 g / L of sulfuric acid and 5 g / L of cobalt sulfate were subjected to AC electrolysis at a current density of 0.8 A / dm ² for 60 seconds, and then titanium was deposited to form a substrate [C-1]. .
When the lithographic printing plate [C-1] was observed with an optical microscope in the same manner as in Example 1, a fine line of 30 μm could be drawn.
In addition, 10,000 clear prints could be printed.

Example 6 In Example 6, the film was formed by a reactive sputtering method. Argon / nitrogen = 50 /
Titanium nitride with a thickness of 500A in an atmosphere of 50
After being formed on a stainless steel substrate having a thickness of 2 mm, fine particles of titanium oxide were filled by alternating current electrolysis, and then titanium was deposited to prepare a substrate [D]. The substrate [D] was irradiated with a YAG laser under the same conditions as in Example 1. When the lithographic printing plate [D] was observed with an optical microscope in the same manner as in Example 1, it was 35 μm.
Could draw a thin line. In addition, 10,000 clear prints could be printed.

(Example 7) In Example 7, 0.2
Aluminum oxide was sprayed onto a stainless steel plate having a thickness of 10 μm by atmospheric plasma, and then subjected to alternating current electrolysis in the same manner as in Example 1. Thereafter, titanium was vacuum-deposited to form a substrate [E]. The substrate [E] was irradiated with a YAG laser under the same conditions as in Example 1. When the planographic printing plate [E] was observed with an optical microscope in the same manner as in Example 1, a fine line of 30 μm was drawn. In addition, 10,000 clear prints could be printed.

Comparative Example 1 In Comparative Example 1, a substrate was prepared and irradiated with a YAG laser in the same manner as in Example 1 except that the alternating current electrolysis was not performed. Observation with an optical microscope revealed that only a fine line of 10 μm could be drawn.

Comparative Example 2 In Comparative Example 2, a substrate was prepared in the same manner as in Example 4 except that no AC electrolysis was performed.
Irradiation with a YAG laser in the same manner as in Example 4 was observed with an optical microscope, and a clear fine line could not be drawn.

Comparative Example 3 In Comparative Example 3, a substrate prepared in the same manner as in Example 5 was irradiated with a YAG laser under the same conditions as in Example 5 except that the substrate was not immersed in a solution of titanium nitride. Observation with an optical microscope revealed that only a fine line of 5 μm could be drawn.

(Comparative Example 4) In Comparative Example 4, a substrate prepared in the same manner as in Example 6 was irradiated with a YAG laser under the same conditions as in Example 6 except that no AC electrolysis was performed. As a result, only a fine line of 10 μm could be drawn.

(Comparative Example 5) In Comparative Example 5, a substrate prepared in the same manner as in Example 7 was irradiated with a YAG laser under the same conditions as in Example 7 except that no AC electrolysis was performed. As a result, only a fine line of 10 μm could be drawn.

Table 1 shows the test results.

[0073]

[Table 1]

As is clear from Table 1, the lithographic printing plates of the examples according to the present invention have high sensitivity, can perform high-definition drawing, and have satisfactory results with respect to printing stains and printing durability. However, the lithographic printing plates of Comparative Examples were not satisfactory because high-definition drawing could not be performed.

[0075]

As described above, a lithographic printing plate according to the method for producing a lithographic printing plate of the present invention can use a porous substrate in which a light-to-heat conversion material is embedded, or can be ablated on the porous substrate by laser exposure. By providing a suitable lipophilic layer, a lithographic printing screen is formed in which the non-irradiated portion accepts ink only by imagewise exposure with active light, and the irradiated portion does not accept ink due to ablation by imagewise irradiation of laser light A lithographic printing screen is formed, and any type of lithographic printing requires no developing solution, and lithographic printing with a clear printed surface is possible. On-press plate making is also possible. Furthermore, according to the present invention, it is possible to provide a method for producing a lithographic printing plate having high sensitivity, high-definition drawing, excellent printing smear, and excellent printing durability.

Claims (1)

[Claims] 1. A lithographic printing plate precursor having a porous substrate having a porous surface layer in which a light-to-heat conversion material is embedded is irradiated with laser light in an image-like manner to make the irradiated portion hydrophilic. Lithographic printing plate manufacturing method.