JPS63102936A - Processing method - Google Patents

Abstract

PURPOSE:To cure a picture in a short time, by a method wherein after forming an ink image containing photosensitive resin on a printing plate material by actuating an ink jet head with an electric signal corresponding to a image signal, the picture is cured by irradiation of light. CONSTITUTION:A copy picture to be processed is made data to electric signal and a photosensitive ink image is formed on a printing plate material by actuating an ink jet head following this electric signals. Then, the printing plate material having the ink image is exposed, and the ink image is cured. The photosensitive ink to be used should preferably be solidified and cured by exposure and be able to form a film of high affinity with offset ink or the like and high durability. The optimum photoresin is the resin solution, used in conventional paint or printing ink fields, which is cured by polymerization with beam or ultraviolet rays.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a plate-making method, and more particularly to a quick and easy plate-making method using an inkjet method.

(Prior Art) Conventionally, printing methods such as lithographic printing, intaglio printing, and letterpress printing have been widely used as printing methods. These methods have been used for a long time and are mainly used for mass printing in factories.

On the other hand, the duplicating method has been used for a long time in small factories and various offices.

Furthermore, in recent years, as quick and easy small-scale printing methods that can be carried out in offices, etc., methods using electrophotography or silver halide printing plates, methods using word processors, personal computers, facsimile printers, etc. have become widely used. It has become.

(The interlayer point that the invention is trying to solve) Among the simple printing methods mentioned above, the method using electrophotography is a quick and easy method. Since the toner image is formed and used as a printing plate (offset master), there is a problem that the toner image does not have sufficient strength against printing ink, and therefore the printing durability is insufficient.

Although a printing plate having sufficient printing durability can be obtained in the silver halide photographic method, the plate making process is long and silver is expensive, so it is unsatisfactory as a simple printing method for use in offices and the like.

In addition, methods using various printers have the advantage of not using printing plates, but because they print one sheet at a time, they are not suitable for applications that require tens, hundreds, or dozens of copies. Moreover, there is a problem that a large amount of ink ribbon etc. is consumed.

Therefore, there is a need for a technology that can provide printing plates with high printing durability that can be easily and conveniently made into plates in small factories and various offices, and can print tens to tens of thousands of sheets.

(Means for Solving the Problems) As a result of intensive research to meet the above-mentioned demands, the present invention provides a plate-making method that can fully meet the above-mentioned demands by utilizing a conventionally known inkjet method for plate-making. completed.

That is, the present invention is characterized in that an inkjet head is operated by an electric signal corresponding to an image signal to form an ink image containing a photosensitive resin on a printing plate material, and then the image portion is cured by light irradiation. This is a plate-making method.

Next, to explain the present invention in more detail, the method of the present invention basically consists of the following three steps.

(+) Process of converting the original image to be made into data into an electrical signal; (2) activating the inkjet head according to the electrical signal obtained in (1) to form a photosensitive ink image on the printing plate material; (3) A process of exposing the printing plate material having the ink image to light to cure the ink image.

The process of (1) above is based on the input image 5 of a word processor or computer.
It is the process of converting image signals transmitted by facsimile transmission systems, color separation images of monochrome or multicolor photographs, halftone images, etc. into data and converting them into electrical signals, and the image information is sent to an inkjet printer. Any conventional method of converting images into data and electrical signals may be used without any particular limitation.

In step (2), the inkjet head is operated according to the image signal in step (1) to form a desired ink image on the printing plate material. An inkjet method may also be used without particular limitation.

In addition, the printing plate material may be a material that repels ink in the non-image area, such as a conventionally known offset master plate coated with zinc oxide, a waterless planographic plate coated with a silicone compound, or a grained aluminum plate. Any material may be used, and it may also be a plate material whose non-image areas become hydrophilic upon exposure.
For example, 0-quinonediazide compounds, spiropyrans,
It may also be a plate material coated with a combination of an amino compound and carbon tetrabromide, a polymeric fluorocarbon compound, or the like.

The above-mentioned 0-quinonediazide compound becomes indenecarboxylic acid by exposure to light, the spiropyran compound develops an ionic structure developed and developed by exposure to light, and the combination of an amino compound and carbon tetrabromide transforms the amino compound into quaternization by exposure to light. Polymer fluorocarbon compounds become hydrophilic when fluorinated.

As mentioned above, the printing plate material used in the present invention may be any printing plate material, and an appropriate one may be selected from conventionally known printing plates.

The main feature of the present invention is that an image is formed using an ink containing a photosensitive resin on any plate material as described above by an inkjet method, and is then cured.

The photosensitive ink used in the present invention may be any ink that can solidify and harden upon exposure to form a highly durable coating that has high affinity for offset inks, etc., and can be used in the production of conventional printing plates. Any solution or dispersion of a photosensitive resin used in photoresists, etc., and ICs can be used, but the photosensitive resin most suitable for the method of the present invention is one that has not been conventionally used in the paint and printing ink fields. It is a resin liquid that polymerizes and cures with electron beams or ultraviolet rays.

Such a photopolymerizable resin liquid preferably consists of a curable component such as a polymerizable polymer, prepolymer, or oligomer, a reactive diluent, a solvent, a photopolymerization initiator, a dye, and other optional additives. The solvent is mainly used to adjust the viscosity of the ink and is preferably present, but is not essential. The photopolymerization initiator is not necessarily required when the curing means is an electron beam, and the presence of the dye is preferable, but not essential, since it makes the formed image visible.

As a curable component, polyester acrylate (in addition,
The term "acrylate" in the present invention means both "acrylate" and "methacrylate"), polyether acrylate, epoxy acrylate, alkyd acrylate, urethane acrylate, unsaturated polyester, etc. Among them, acrylate photosensitive resins are particularly preferred.

Furthermore, in order to form a highly lipophilic film, it is preferable to use an oil-modified acrylate photosensitive resin modified with a highly lipophilic fatty acid or the like.

Reactive diluents are used because the ink has a high viscosity and sufficient crosslinking density cannot be obtained with the above-mentioned curable components alone, and examples include styrene, divinylbenzene, methyl acrylate, and ethyl acrylate. , trimethylolpropane triacrylate, pentaerythritol tetraacrylate, 1,4-butane diacrylate, 1,6-hexane diacrylate, -hydric or polyhydric phenols and alicyclic alcohols (e.g. 1,4-bishydroxy Used are those obtained by adding alkylene oxide to (methylcyclohexane) and further acrylating it with acrylic acid, methacrylic acid, etc. In particular, if a relatively large amount of a diacrylate or higher polyfunctional reactive diluent is used, a printing plate with higher printing durability can be provided.

Photopolymerization initiators are necessary when curing ink images with ultraviolet rays, and include, for example, benzophenone derivatives, acetophenone derivatives, benzoin alkyl ethers, thioxanthone derivatives, ρ-dialkylaminobenzoic acid, and various amines. A sensitizer may be used in combination.

Solvents mainly reduce and adjust the viscosity of the ink, and include ketones such as methyl ethyl ketone, pentanone, hexanone, cyclohexanone, and camphor; ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, and 3-methoxy acetate. Butyl, acetic acid 2
- Esters such as ethylhexyl, ethyl propionate, isopentyl propionate, ethyl 2-hydroxy-2-methylpropionate, methyl butyrate; Ethers such as dibutyl ether, butyl vinyl ether, phenetol, methoxytoluene, diphenyl ether; toluene, xylene, Aromatic compounds such as ethylhexyl, mesitylene, and pentylbenzene; Halogenated hydrocarbons such as dichloroethane, dichloropropane, and chloropentane; isopropyl alcohol, isopentyl alcohol, 3-
Methyl-2-butanol, hexanol, 4-methyl-
2-pentanol, heptatool, octatool, 2-
Ethyl-hexanol, ethylene glycol, methyl cellosolve, ethyl cellosolve, propylene glycol,
Examples include alcohols such as diacetone alcohol, butanediol, and glycerin.

It is desirable to use a mixture of each of these solvents, and if only a low-boiling point solvent is used, the solvent may evaporate at the nozzle tip of the inkjet head and cause nozzle clogging, so it is recommended to use a mixture of high-boiling point solvents. It is desirable to do so. In addition, a binder, a physical property modifier such as viscosity, surface tension, etc. can also be added as auxiliary materials. As the binder, natural resins such as shellac and casein, and polymers such as styrene-maleic acid copolymer and polyacrylate are used. Moreover, various surfactants are used as physical property modifiers. Furthermore, when there is a risk that the ink may bleed on the printing plate material, a thickener or the like may be added to the ink to adjust the physical properties of the ink.

The components of the ink used in the present invention consist of the above-mentioned components as long as a desired ink image can be formed on the printing plate material by the inkjet method and a film having affinity for the printing ink can be formed by exposure. It is not limited to ink, but may be formed from any other photosensitive resin, the ink must have a high curing speed, it must have good adhesion to the printing plate material, and it must have good halftone reproducibility. From the viewpoints of good adhesion, high printing durability, etc., it is preferable to use an ink whose main component is an acrylate-based photosensitive resin such as the one mentioned above. Ingredients: 5-40% by weight of the total, reactive diluent: 10-40% by weight
A suitable composition is 60% by weight, 0.1 to 10% by weight of photopolymerization initiator, 10 to 80% by weight of solvent, and 30% by weight or less of dye, and the viscosity of the obtained ink is about 2. Q
It is preferable to set it to OOcps (25°C) or less.

A desired image is formed on a printing plate material by an inkjet method using ink containing the photosensitive resin as described above, but these images may be solid images without halftones such as characters or figures, or monochrome images. It may be a halftone image with halftones like a photographic image, or it may be a color-separated image of cyan, magenta, yellow, etc. (a halftone image is fine), or a variety of these images. It may be a combination of images, and the types of images are not particularly limited. Further, since the image formed as described above has a high resolution of 16 or more lines per mm in various current inkjet printers, the image has a very high resolution, and there is no particular problem in terms of resolution.

The method of curing the ink image itself in the step (3) above may be in accordance with conventionally known methods and conditions.
Electron beams from electron beam irradiation equipment, ultraviolet rays generated from light sources such as high-pressure mercury lamps, medium to low-pressure mercury lamps, xenon lamps, arc lamps, metal halide lamps, etc. can all be used, and the irradiation time is from several seconds to several minutes. A short time is sufficient, resulting in a sufficiently crosslinked and cured ink image.

The printing plate obtained according to the present invention may be further subjected to a development treatment, if necessary, to further increase the difference in hydrophilicity between the non-image area and the image area. For example, as a developing method, elution with an organic solvent, elution with alkaline water, elution with water, elution with ultrasonic treatment, development method with heating or reduced pressure, etc. can be used.

Furthermore, if necessary, the ink image can be colored, or the surface of the image area can be treated to make it more lipophilic by using a highly lipophilic material, such as a chimfer.

The printing plate obtained as described above can be directly applied to a conventionally known printing machine for printing.

(Function/Effect) According to the present invention as described above, the steps of image processing of a document, formation of an ink image using an inkjet method, and curing of an image can all be completed in a very short time and do not require expensive materials. Since there is no need to use it, there are no problems of process complexity or cost concerns.

In addition, since the image formed on the plate is made of a highly crosslinked and extremely tough photosensitive resin, especially an acrylate resin, it has significantly higher printing durability than conventional toner images. , it has a printing durability of several tens to tens of thousands of sheets, and the problem of printing durability of the prior art has been fully solved.

In addition, as a unique effect of the present invention, if the ink of the inkjet printer according to the present invention is matched with the printing ink, the color image of the inkjet printer becomes a blueprint, and the creation of a blueprint that currently takes several days can be done in just a few hours. It can be delivered to the user's hands without the need for printing, speeding up printing.

Next, the present invention will be explained in more detail with reference to Examples. These Examples are preferred illustrations of the present invention and are not intended to limit the present invention in any way.

Example 1 A thousand color images formed on a television screen were converted into halftone dot signals, and then printed out using an inkjet printer on a zinc oxide coated plate (manufactured by Murakami Photo Film) using an ink with the following composition. .

Eno Sarajo bovinyl pyrrolidone 15 parts by weight Pentaerythritol triacrylate 40 parts by weight Benzophenone 3 parts by weight Michler's ketone 3 parts by weight Glycerin
10 parts by weight Methylcalpitol 5 parts by weight Holon
5 parts by weight methyl isobutyl ketone
10 parts by weight Next, the above ink image was exposed for 30 seconds from a distance of 70 cm using a 3 KW high pressure mercury lamp to fully cure the ink image, and a printing plate was prepared. This printed version is
4 to 95% halftone dots with a screen line count of 85 lines/inch were accurately reproduced.

When the above printing plate was printed with black ink using a regular simple offset printing machine, the ink receptivity and halftone reproducibility were good, and there was no disturbance in the printed image even after printing a single 3T sheet. .

Example 2 After converting a monochrome image formed on a high-performance television screen into a halftone dot signal, it was printed out using an inkjet printer using an ink having the following composition on a grained aluminum plate material with a thickness of 10 μm.

Bovinyl pyrrolidone loi [Part I Pentaerythritol triacrylate 30 parts by weight Bis(hydroxyethylcarbamoylcyclohexyl)
Methane diacrylate 5 parts by weight Di-butylciberoxyisophthalate 3 parts by weight 4-(4-butoxyphenyl)-2,6-cyphenylthiapyrylium fluoroborate 4 parts by weight Glycerin 10 parts by weight Methylcarpitol 6 parts by weight Holon
5 parts by weight methyl isobutyl ketone
15 parts by weight Next, add the above ink image to 70 c
The ink image was sufficiently cured by exposure for 30 seconds from a distance of 100 m from a 3 KW high-pressure mercury lamp, and a printing plate was prepared. This printing plate has a screen line of 4 to 95% of the A85 line/inch.
The halftone dots were reproduced with high accuracy.

When the L printing plate was printed with black ink on a regular off-wheel printing machine, the ink receptivity and halftone reproducibility were good, and there was no disturbance in the printed image even after printing 30,000 sheets. Ta.

Example 3 A color image formed on a high-performance television screen is separated into yellow, red, blue, and black using a color scanner, and based on this color separation electrical signal, lead oxide coating is performed using an inkjet printer using an ink with the following composition. Each decomposed image was printed out in a halftone pattern on a board.
sPentaerythritol triacrylate 40 parts by weight Dibutylciberoxyisophthalate 3 parts by weight 4-(4-butoxyphenyl)-2,6-cyphenylthiavirylium fluoroborate 3 parts by weight Glycerin 10 parts by weight Methylcarpitol 10 Parts by weight Methyl isobutyl ketone 10 parts by weight Next, each of the ink images in item 21 was exposed for 30 seconds from a distance of 70 cm using a 3 KW high pressure mercury lamp to fully cure the ink images, and a printing plate was prepared.

When these square printing plates were subjected to color printing using a conventional off-wheel printing machine, a color image with good ink receptivity, halftone dot reproducibility, etc. was obtained.

Claims (2)

[Claims] (1) A plate-making method characterized by activating an inkjet head with an electric signal corresponding to an image signal to form an ink image containing a photosensitive resin on a printing plate material, and then curing the image portion by light irradiation. (2) The plate-making method according to claim (1), wherein the photosensitive resin is an acrylate photosensitive resin.