JPH11242343A - Image forming method - Google Patents

Abstract

PURPOSE: To obtain an image forming method excellent in the reproducibility of dots and the resolution and suitable for making a printing plate, etc., by removing a part where adhesive ability to a supporting body is lower by simultaneously using both of either a scattering method or a suction method by means of air and a brush rubbing method. CONSTITUTION: When planographic printing plate material P is inserted in a carrying roller 2, a compresser 6 and a vacuum pump 7 are actuated and an air jet/vacuum roller 3 whose surface is formed with a rotating brush 4 also starts to rotate. When the material P comes to a position under the roller 3, the part of a photosensitive layer where the adhesive ability of the material P to the supporting body is lower is rubbed by the brush 4 and simultaneously scattered from the supporting body by the pressure of air blowing out from a minute hole on the surface of the roller 3. The scattered residue is sucked by the vacuum pump 7 from a small hole 5a bored on the surface of a developing residue recovery nozzle 5 and recovered to a developing residue tank 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method,
More specifically, it is suitable for the production of color proofing sheets, mask images, printing plates, etc. by dry development, in which the processing step and the processing time are short, there is no need to manage the processing solution, and the processing of waste discharged in the processing is simple. The present invention relates to an image forming method.

[0002]

2. Description of the Related Art As a printing plate manufacturing technique, a difference in solubility or swelling property in a developing solution is caused between an exposed portion and an unexposed portion by image exposure of a photosensitive layer, and elution development is performed using a developing solution. The techniques used are widely known and are in practical use. On the other hand, technology that solves the disadvantages of such wet processing, that is, problems such as long processing steps and processing time, necessity of management of processing liquid, and complicated processing of waste liquid discharged in processing are solved. As a method, there has been proposed a method of manufacturing a printing plate by a dry method without using a liquid processing agent. That is, JP 49
In JP-99610, a photopolymerizable photosensitive layer that is liquid adhesive at room temperature is provided on a support, and after image exposure, the photopolymerizable photosensitive layer in the unexposed area is removed by air flow without using a liquid developer and printed. A method for forming a plate is disclosed. JP-A-52-13901 discloses that a positive film is superimposed on a resin plate based on a photo-degradable resin on a support, image-exposed, and the irradiated portion is powdered. A method for producing a printing plate that is removed by scattering or suction by air is disclosed.

[0003]

SUMMARY OF THE INVENTION However, the above problem has been solved in that the sufficient resolution and halftone dot reproducibility cannot be obtained, particularly because the developability of the shadow portion of the image is insufficient. There is a problem that the liquid tacky photosensitive layer adheres to the automatic developing machine, and the maintenance of the automatic developing machine is troublesome. The above-mentioned problem is that the maintenance of the automatic developing machine is relatively easy, but sufficient dot reproducibility and resolution cannot be obtained similarly to the above. Further, a method of scattering or sucking with air after pulverizing a part weakened by image exposure by brushing or the like is also disclosed, which improves dot reproducibility and resolution, but the degree is small. .

[0004] An object of the present invention is to reduce halftone dot reproducibility and resolution by dry development in which the working process and the processing time are reduced, the management of the processing solution is unnecessary, and the waste discharged in the processing is simple. An object of the present invention is to provide a good image forming method suitable for producing a printing plate or the like.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to form a photosensitive layer on a support, and to produce a difference in the adhesiveness between an exposed portion and an unexposed portion of the photosensitive layer by image exposure. In other words, this is achieved by an image forming method characterized in that a portion having lower adhesiveness to the support is removed by simultaneously using either a scattering method using air or a suction method and a brush rubbing method.

Hereinafter, the present invention will be described in detail.

As the support of the image forming material used in the image forming method of the present invention, a transparent support, an opaque support, a lithographic printing plate, or the like can be appropriately selected and used depending on the application.

As a transparent support used for an image forming material such as a mask image, it does not affect photographic properties,
Any material can be used as long as it is dimensionally stable and transparent to light used for recording. Typical supports include nitrocellulose film, triacetyl cellulose film, polyvinyl acetal film, polystyrene film, polyethylene terephthalate film,
Examples include polycarbonate films, poly-α-olefins such as polyethylene, polypropylene films and other resin films. It is preferable that the surface of these supports is subjected to an appropriate subbing treatment in order to improve the coating properties of the photosensitive layer and the adhesiveness of the photosensitive layer. Further, an antihalation layer containing a dye or a pigment may be provided on the front or back surface of these supports for the purpose of preventing halation or the like.

The surface of the transparent support opposite to the side on which the photosensitive resin layer is provided may have a matte surface for the purpose of improving the slipperiness of the recording material and the adhesion to the original at the time of exposure. preferable.

The thickness of the transparent support is preferably 50 μm or less, more preferably 4 to 20 μm. When a support thinner than 4 μm is used, the dimensions of the support become unstable. If the thickness is more than 20 μm, the image quality deteriorates due to diffusion in the support during image exposure.

As an opaque support used for an image forming material such as a color proofing sheet, paper (for example, art paper) or the like can be used.

For a lithographic printing plate, a pure aluminum plate, an aluminum alloy or another metal plate whose surface is coated with aluminum or an aluminum alloy, a film, paper, or the like can be used. Among these, a substrate such as an aluminum plate or a three-layer plate in which a resin layer is sandwiched between aluminum or an aluminum alloy is preferable.

The surface of the aluminum support is grained by a mechanical method such as a brush polishing method or a ball polishing method, an electrochemical method such as electrolytic polishing, or a combination thereof. In the case of electrolytic polishing, nitric acid, hydrochloric acid, sulfuric acid or a mixed acid thereof is used as an electrolytic solution, and electrolytic surface roughening conditions are 0.1 to 0.5 mol / l, preferably 0.2 to 0.4 m
immersing the aluminum support in a bath containing ol / l nitric acid,
20-50 ° C, preferably 25-45 ° C, current density 20-20
It is preferably about 10 seconds to 3 minutes at 0 A / dm ² . It is also preferable to perform mechanical polishing such as ball polishing, brush polishing, liquid honing, and buff polishing prior to the electrolytic etching.

The electropolished aluminum support is desirably chemically cleaned. This is because it has an effect of removing so-called smut, which is a surface residue, from the surface. As such a processing, for example, JP-B-48-28123
Japanese Patent Application Laid-Open No.
A treatment method such as a sulfuric acid desmut method described in JP-A-53-12739 may be used.

After this electrolytic polishing, it is preferable to further perform an anodic oxidation treatment to form an anodic oxide film on the aluminum support. Anodizing treatment uses sulfuric acid, chromic acid,
An aqueous solution containing one or more of oxalic acid, phosphoric acid, malonic acid or the like at a total concentration of 10 to 50% is used as an electrolytic solution with an aluminum support as an anode and an electrolytic density of 1 to 10 A / dm ^2.
For 10 seconds to 2 minutes. There is also a method of electrolysis at a high current density in sulfuric acid described in another U.S. Pat. No. 1,412,768. The formed anodic oxidation amount is suitably 1 to 50 mg / dm ² , preferably 5 to 50 mg / dm ^2.
3030 mg / dm ² .

The anodized aluminum support may be further treated by immersion in an aqueous solution of an alkali metal silicate, such as sodium silicate, as described in US Pat. Nos. 2,714,066 and 3,181,461; No. 3,860,426, an undercoat layer of hydrophilic cellulose (eg, carboxymethylcellulose, etc.) containing a water-soluble metal salt (eg, zinc acetate, etc.) is provided, or polyvinylphosphone is described in US Pat. No. 4,153,461. It may be treated with an acid.

The composition for forming the photosensitive layer in the present invention may be any composition that causes a difference in the adhesiveness of the photosensitive layer to the support upon exposure. As such a composition,
Examples include a photopolymerization system, a photodecomposition system, a polyhalogen / resin system, and a photoacid decomposition system.

The following are examples of the photopolymerizable composition. As the binder component, a polymer having thermoplasticity and excellent compatibility with the photopolymerization component is used. For example, polyvinyl chloride, chlorinated polyolefin, poly (meth)
Acrylic ester, epoxy resin, polyurethane resin, cellulose derivative, polyamide resin, polyvinyl-
Butyral resin, polyvinyl acetal resin, polyvinyl pyrrolidone, gelatin, diallyl phthalate resin, butadiene-acrylonitrile copolymer, polyvinyl acetate, vinyl versatate, and the like.

As the photopolymerizable component, the following ethylenically unsaturated compounds are used. Representative compounds include 2-hydroxyethyl (meth) acrylate, ethylene glycol diacrylate, diethylene glycolodiacrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, Examples thereof include dipentaerythritol triacrylate and dipentaerythritol hexaacrylate, and one or more of these ethylenically unsaturated compounds can be used. The photopolymerization component is used in an amount of 10 to 500 parts by weight, preferably 30 to 200 parts by weight, based on 100 parts by weight of the binder component.

As the photopolymerization initiator, conventionally known photopolymerization initiators can be suitably used. Specific examples include benzophenone, 4,4-bis (diethylamino) benzophenone,
Examples include methoxy-4-dimethylaminobenzophenone, 2-ethylanthraquinone, phenanthraquinone, benzoin, benzoin methyl ether and the like. Further, as preferred thermal polymerization inhibitors, p-methoxyphenol, hydroquinone, t-butylcatechol, pyrogallol, pyridine, aryl phosphite and the like can be appropriately used.

If necessary, the photopolymerizable composition may be used as a sensitizing aid such as Michler's ketone,
Amine compounds such as 4,4'-bisdiethylaminobenzophenone can be used.

The thickness of the photosensitive layer is not particularly limited.
It may be about 5 μm. The appropriate coating amount varies depending on the contained components, but usually 0.5 to 30 g / m ² is appropriate. Upon application, a bar coater or the like can be used, and for example, a spin coater or a similar coater may be used.
Optional.

As the photodecomposition type composition, for example, JP-A-52
-13901, as a polyhalogen / resin-based composition,
For example, JP-A-53-23632, JP-A-54-153622, as a photoacid decomposition system composition, for example, JP-A-48-89003
And JP-A-51-120714 and JP-A-53-13342.

The photosensitive layer and / or other layers provided on the support may contain a coloring agent described in JP-A-4-172351, a visible light exposure agent, an irradiation inhibitor and the like. As the exposure visible image agent, a combination of a photoacid generator and an organic dye capable of fading or discoloring with an acid can be mentioned. As the photoacid generator, JP-A-60-138539, JP-B-60-27673, JP-B-60-27673 Organic halogen compounds described in JP-A-49-21601, JP-A-63-58440, JP-B-57-1819;
No., JP-B-54-14278, JP-A-51-56885, U.S. Pat.
No. 3,708,296, diazonium salts, iodonium salts, and sulfonium salts described in 3,835,002 and the like,
Examples of the organic dye include various dyes such as diphenylmethane, triphenylmethane thiazine, oxazine, xanthene, anthraquinone, iminonaphthoquinone, azomethine, and arylamines. Further, between the support and the photosensitive layer, a release layer as described in JP-A-4-39662 or a layer made of a heat-softening composition described in JP-A-4-172351 can be provided. A protective layer can be provided on the photosensitive layer.

Next, a description will be given of a method of exposing the photosensitive layer to a portion having a lower adhesiveness to the support after the image exposure. The light source for image exposure is not particularly limited as long as the light causes a curing reaction to the photosensitive layer. The contact exposure may be performed through a transmission original, or the line-sequential or point-sequential scanning exposure may be performed using a modulatable light source such as a laser beam. In the case of a transparent support, image exposure may be performed from the support side.

In order to remove a portion of the photosensitive layer having lower adhesiveness to the support by simultaneously using either the scattering by air or the suction method and the brush rubbing method, for example,
An automatic developing machine schematically shown in FIG. 1 can be used. In the figure, a lithographic printing plate material P, which is a photosensitive material having a photosensitive layer on a support used in the image forming method of the present invention, is inserted into an automatic developing machine with the photosensitive layer facing upward in the direction of arrow A and a carry-in roller. 1 and the transport roller 2 to be transported horizontally.

Numeral 3 denotes an air jet / vacuum roller for injecting air to or sucking the upper surface of the lithographic printing plate material P. The air jet / vacuum roller 3 is rotatable by a drive mechanism (not shown). The present invention mainly comprises a hollow cylinder provided with a large number of minute holes 3a through which air can flow on a peripheral surface thereof, and a pipe 3b for feeding air into the hollow cylinder or sucking air from the interior. The air can be scattered or sucked by air. The bristles used in the brush rubbing method of the present invention are planted on the peripheral surface of the air jet / vacuum roller 3 to form the rotating brush 4. Reference numeral 5 denotes a developing residue collecting nozzle used in the suction method of the present invention for sucking a portion of the photosensitive layer having lower adhesion to the support and removing the portion from the support. The developing residue collecting nozzle 5 is provided above the conveying surface of the lithographic printing plate material P in a direction perpendicular to the conveying direction.
The inside of the tube is reduced in pressure by a vacuum pump 7 through a tube 5b, and the photosensitive layer of the lithographic printing plate material P is sucked through the small hole 5a. Reference numeral 6 denotes a compressor for feeding air to the air injection / vacuum roller 3, 7 denotes a vacuum pump for sucking air from the air injection / vacuum roller 3 and the developing residue collecting nozzle 5, and 8 denotes a cock for switching between the compressor 6 and the vacuum pump 7. When the compressor 6 is used, the switching cock 8 moves in the direction of the arrow marked with *, and when the compressor 6 is not used, the switching cock 8 moves in the direction of the arrow drawn by the vacuum pump 7 without the mark *. The air is flowing. Whether or not to use the compressor 6 is selected on an operation panel (not shown), whereby the switching of the switching cock 8 and the operation of the compressor 6 are controlled. Reference numerals 9 and 10 denote a developing residue tank for accommodating the photosensitive layer removed by the removing method of the present invention, and reference numeral 11 denotes a cover for preventing the removed photosensitive layer from scattering around. When the lithographic printing plate material P is inserted into the automatic developing machine, the carry-in roller 1, the transport roller 2, and the air jet / vacuum roller 3 whose surface is formed on the rotating brush 4 start rotating by a control mechanism (not shown). When the vacuum pump 7 operates and the compressor 6 is used, the compressor 6 is also configured to start operating.

Next, the operation of the automatic developing machine shown in FIG. 1 will be described. First, when the use of the compressor 6 is set on the operation panel of the automatic developing machine, whether or not the switching cock 8 and the compressor 6 are operated is set by a control mechanism (not shown).

When the lithographic printing plate material P is inserted into the carry-in roller 1 from the left end in FIG.
The compressor 6 and the vacuum pump 7 operate, and the air jet / vacuum roller 3 whose surface is formed on the rotating brush 4
Also start spinning. When the lithographic printing plate material P comes under the air jet / vacuum roller 3, the portion of the photosensitive layer having lower adhesion of the lithographic printing plate material P to the support is rubbed with the rotating brush 4 and at the same time air jet / vacuum. The particles are scattered from the support by the pressure of air blown out from minute holes in the surface of the roller 3. The scattered residue is sucked by a vacuum pump 7 from a small hole 5a opened in the surface of the developing residue collecting nozzle 5 and collected in a developing residue tank 10, and the residue that cannot be completely collected by the developing residue collecting nozzle 5 is developed. Deposited on

When the lithographic printing plate material P is inserted into the carry-in roller 1 of the automatic developing machine when the compressor 6 is not used, the vacuum pump 7 is operated, and the air jet / vacuum whose surface is formed on the rotating brush 4 is used. The roller 3 also starts rotating. When the lithographic printing plate material P comes under the rotating brush 4, the portion of the photosensitive layer having lower adhesion of the lithographic printing plate material P to the support is rubbed with the rotating brush 4 and at the same time as the air jet roller / vacuum roller 3. Is sucked by a vacuum pump 7 from a minute hole on the surface of the developing device and collected in a developing residue tank 10. Residues that cannot be completely collected by the air jet roller / vacuum roller 3 are sucked by a vacuum pump 7 from a small hole opened in the surface of a developing residue collecting nozzle 5 and collected in a developing residue tank 10.
Further, it is deposited on the developing residue tank 9.

[0031]

Next, the present invention will be described more specifically with reference to examples.

Example 1 A coating solution for a photosensitive layer having the following composition was prepared.

Coating solution for photosensitive layer 2,4-dimethylthioxanthone 0.6 g diallyl isophthalate prepolymer 6.0 g chlorinated polyethylene 4.0 g carbon black MA-100 (manufactured by Mitsubishi Kasei Corporation) 3.0 g xylene 100 g coating for this photosensitive layer The liquid was applied on a 100 μm-thick polyethylene terephthalate film to a dry film thickness of 2 μm to obtain an image forming material. After exposing the image forming material through the mask from the photosensitive layer side, the image was developed using the automatic developing machine shown in FIG. 1 together with the scattering by air and the brush rubbing method. The black color corresponding to the mask was formed on the polyethylene terephthalate film. Was obtained. Table 1 shows the dot reproducibility. The dot reproducibility is shown in the range of the dot area ratio at which a dot image of 150 lines / in. Can be reproduced.

Example 2 The same experiment as in Example 1 was conducted except that dipentaerythritol hexaacrylate was used as the polymerizable monomer in the composition for the photosensitive layer coating solution. Table 1 shows the results.

Example 3 The same experiment as in Example 1 was carried out except that a solution having the following composition was used as the coating solution for the photosensitive layer. Table 1 shows the results.

Coating solution for photosensitive layer Phenyl vinyl ketone-styrene copolymer (molar ratio = 50/50, average molecular weight 30,000) 10 g Carbon black MA-100 (manufactured by Mitsubishi Kasei Corporation) 3.0 g Methyl ethyl ketone 100 g Example 4 Photosensitivity A printing plate was prepared in the same manner as in Example 1 except that a liquid having the following composition was used as a coating solution for a layer, and a grained aluminum plate was used as a support. The printing plate obtained was set on a printing press and printed on woodfree paper. Good printed matter was obtained. Table 1 shows the dot reproducibility.

Coating solution for photosensitive layer Cresol novolak resin (average molecular weight 5000) 10 g Iodoform 1 g Methyl ethyl ketone 100 g Example 5 A printing plate was prepared in the same manner as in Example 4 except that a solution having the following composition was used as the coating solution for the photosensitive layer. did. The printing plate obtained was set on a printing press and printed on woodfree paper. Good printed matter was obtained.

Coating solution for photosensitive layer Formaldehyde and 1,5-pentanediol polyacetal 10 g 2-tribromomethylquinosaline 1 g Triethylene glycol diacetate tetrahydrofuran 100 g Comparative Example 1 A coating solution for the photosensitive layer having the following composition was used. The same experiment as in Example 1 was conducted except that the development was performed only by scattering by air. Table 1 shows the results.

Coating solution for photosensitive layer Unsaturated polyester obtained from maleic anhydride and diethylene glycol (average molecular weight: 1500) 65 g styrene 35 g benzoin methyl ether 1.5 g carbon black MA-100 (manufactured by Mitsubishi Chemical Corporation) 3.0 g Comparative Example 2 The same experiment as in Example 3 was performed except that the development was performed only by the suction method. Table 1 shows the results.

Comparative Example 3 The same experiment as in Comparative Example 2 was performed except that the brush was rubbed before the development by the suction method. Table 1 shows the results.

Comparative Example 4 The same experiment as in Example 4 was conducted except that the brush was rubbed in advance before the development by scattering by air. Table 1 shows the results.

Comparative Example 5 The same experiment as in Example 4 was performed except that the development was performed only by brush rubbing. Table 1 shows the results.

[0043]

[Table 1]

[0044]

According to the present invention, halftone dots can be reproduced by dry development, in which the image forming work process and processing time are shortened, the management of the processing liquid is not required, and the waste discharged in the processing is easily processed. The present invention provides an image forming method that is suitable for producing a printing plate, a color proof image, and the like, which has good performance and resolution.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of an apparatus for performing a method of the present invention.

[Explanation of symbols]

 3 Air injection / vacuum roller 4 Rotary brush 5 Developing residue collecting nozzle 6 Compressor 7 Vacuum pump 8 Switching cock 9, 10 Developing residue tank P Lithographic printing plate material

Claims (1)

[Claims] 1. A photosensitive layer is formed on a support, and image exposure causes a difference in adhesiveness between an exposed portion and an unexposed portion of the photosensitive layer to the support, and the adhesiveness to the support is lower. An image forming method characterized in that a portion is removed by simultaneously using either a scattering method using air or a suction method and a brush rubbing method.