JP2542500B2 - Plate making method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a plate making method, and more particularly to a rapid and simple plate making method using an inkjet method.

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

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

Furthermore, in recent years, as a quick and simple small-scale printing method that can be performed in offices, a method using a plate by an electrophotographic method or a silver salt photographic method, a method using a printer such as a word processor, a personal computer, and a facsimile is widely used. It has become.

(Problems to be Solved by the Invention) Among the above simple printing methods, the method utilizing an electrophotographic method is a quick and simple method, but a toner image is formed on a zinc oxide coated sheet by the electrophotographic method. However, since this is used as a printing plate (offset master), the toner image does not have sufficient strength with respect to the printing ink, and therefore there is a problem that the printing durability is insufficient.

The silver salt photographic method can provide a printing plate having sufficient printing durability, but the plate making process is long and the cost of silver is high, so it is unsatisfactory as a simple printing method used in offices and the like.

Also, although the method of using various printers has the advantage of not using a printing plate, it is not suitable for applications requiring tens, hundreds, or thousands of copies because it prints one by one. In addition, there is a problem that a large amount of ink ribbons and the like are consumed.

Therefore, there is a demand for a technique capable of providing a printing plate having a high printing durability capable of easily and easily making a plate and capable of printing several thousand to tens of thousands of sheets in a small factory or various offices.

(Means for Solving Problems) As a result of earnest research to meet the above demands, the present invention is a plate making method capable of sufficiently satisfying the above demands by utilizing a conventionally known ink jet method for plate making. Was completed.

That is, according to the present invention, an inkjet head is operated by an electric signal corresponding to an image signal, and a curable component selected from polyester acrylate, polyether acrylate, epoxy acrylate, alkyd acrylate and urethane acrylate is reacted in an amount of 5 to 40% by weight. An ink prepared to have a composition of 10 to 60% by weight of a diluent, 0.1 to 10% by weight of a photopolymerization initiator, 10 to 80% by weight of a solvent and 30% by weight or less of a dye is applied onto a printing plate material. To form an image, and the image portion is cured by irradiation with light.

Next, the present invention will be described in more detail. The method of the present invention basically comprises the following three steps.

(1) A process of converting an original image to be plate-formed into data and converting it into an electric signal, (2) In accordance with the electric signal obtained in (1), an inkjet head is operated to form a photosensitive ink image on a printing plate material. Step (3) A step of curing the ink image by exposing the printing plate material having the ink image.

In the process of (1) above, data such as an input image of a word processor or a personal computer, an image signal transmitted by a facsimile transmission system, a color separation image of a mono-color or multi-color photograph, a halftone image thereof, etc. are converted into an electric signal. It is a process such as conversion, and any conventionally known image data conversion and electric signal conversion may be used as long as the image information can be applied to an inkjet printer, and there is no particular limitation.

In the step (2), the inkjet head is operated according to the image signal in the step (1) to form a desired ink image on the printing plate material. The inkjet method may be of any type and is not particularly limited.

Further, the printing plate material is a conventionally known offset master plate material coated with zinc oxide, a waterless planographic material coated with a silicone compound, a grained aluminum plate material, etc., as long as the non-image area is a material that repels ink. Any material may be used, and a plate material whose non-image area changes to hydrophilic by exposure may be used, and examples thereof include o-quinonediazide compounds, spiropyrans, combinations of amino compounds and carbon tetrabromide, and polymeric carbon fluorides. It may be a plate material coated with a compound or the like.

The above-mentioned o-quinonediazide compound is an indenecarboxylic acid upon exposure, a spiropyran compound is an ionic structure which is ring-opened and colored upon exposure, and a combination of an amine compound and carbon tetrabromide is a quaternized amino compound upon exposure,
Further, the high molecular weight fluorocarbon compound is defluorinated and becomes hydrophilic.

As described 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 plate materials and used.

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

The photosensitive ink used in the present invention may be any one as long as it can be solidified and cured by exposure to form a coating film having a high affinity for offset inks and a high durability. Although a solution or dispersion of a photosensitive resin used for photoresists such as ICs and ICs can be used, the photosensitive resin most suitable for the method of the present invention is conventionally used in the field of paints and printing inks. It is a resin liquid that is polymerized and cured by the existing electron beam or ultraviolet rays.

Such a photopolymerizable resin liquid preferably comprises a photopolymerizable polymer, a prepolymer, a curable component such as an oligomer, a reactive diluent, a solvent, a photopolymerization initiator, a dye, and any other additive. The solvent mainly adjusts the viscosity of the ink and is preferably present but not essential. The photopolymerization initiator is not always necessary when the curing means is an electron beam, and the dye makes the formed image visible and is preferably present, but not essential.

As the curable component, polyester acrylate (the term "acrylate" in the present invention means both "acrylate" and "methacrylate"),
Polyether acrylates, epoxy acrylates, alkyd acrylates, urethane acrylates, unsaturated polyesters and the like have an addition-polymerizable double bond in their structure, and acrylate-based photosensitive resins are particularly preferred.

Further, in order to form a film having a higher lipophilicity, it is preferable to use an oil-modified acrylate-based photosensitive resin modified with a fatty acid having a high lipophilicity.

The reactive diluent is used because the above-mentioned curable component alone has a high ink viscosity and a sufficient crosslink density cannot be obtained, and examples thereof include styrene, divinylbenzene, methyl acrylate, and ethyl acrylate. , Trimethylolpropane triacrylate, pentaerythritol tetraacrylate, 1,4-butanediacrylate, 1,6-hexanediacrylate, monohydric or polyhydric phenols and cycloaliphatic alcohols (e.g. 1,4-bishydroxy). Methylcyclohexane) to which alkylene oxide is added and further acrylated with acrylic acid, methacrylic acid, or the like is used. In particular, the use of a relatively large amount of a polyfunctional reactive diluent of diacrylate or higher provides a printing plate having higher printing durability.

The photopolymerization initiator is necessary for curing the ink image with ultraviolet rays, and examples thereof include benzophenone derivatives, acetophenone derivatives, benzoin alkyl ethers, thioxanthone derivatives, p-dialkylaminobenzoic acid, and various amines. The sensitizer may be used in combination.

The solvent mainly reduces and adjusts the viscosity of the ink and includes, for example, methyl ethyl ketone, pentanone,
Ketones such as hexanone, cyclohexanone, camphor; ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, 3-methoxybutyl acetate, 2-ethylhexyl acetate, ethyl propionate, isopentyl propionate, 2-hydroxy-2- Esters such as methyl methyl propionate and methyl butyrate; Ethers such as dibutyl ether, butyl vinyl ether, phenetol, methoxytoluene, diphenyl ether; Aromatic compounds such as toluene, xylene, ethylbenzene, mesitylene, pentylbenzene; Dichloroethane, dichloropropane, Halogenated hydrocarbons such as chloropentane;
Isopropyl alcohol, isopentyl alcohol, 3
-Methyl-2-butanol, hexanol, 4-methyl-2-pentanol, heptanol, octanol, 2
Examples include alcohols such as -ethyl-hexanol, ethylene glycol, methyl cellosolve, ethyl cellosolve, propylene glycol, diacetone alcohol, butanediol, and glycerin.

It is desirable to mix and use these solvents.Since only the low boiling point solvent may evaporate at the nozzle tip of the inkjet head and cause nozzle clogging, mix and use the high boiling point solvent. It is desirable to do. In addition to these, a binder, a physical property adjusting agent such as viscosity and surface tension, and the like can be added as an auxiliary material. As the binder, natural resins such as shellac and casein, and polymers such as styrene-maleic acid copolymers and polyacrylates are used. Various surfactants are used as the physical property adjuster. Further, when the ink is likely to bleed on the printing plate material, a physical property of the ink can be adjusted by adding a thickener or the like to the ink.

The components of the ink used in the present invention are the components exemplified above as long as a desired ink image can be formed on a printing plate material by an inkjet method and a film having an affinity for the printing ink can be formed by exposure. The ink is not limited to ink, and may be formed from any other photosensitive resin, but the ink has a high curing speed, has good adhesiveness with the printing plate material, and has good dot reproducibility. In terms of good printing ink, high printing durability, etc.,
It is preferable that the main component is an acrylate-based photosensitive resin as described above, and the ink composition is generally 5 to 40% by weight of the curable component and 10 to 60% by weight of the reactive diluent.
% By weight, 0.1-10% by weight of photopolymerization initiator, 10-80 by solvent
A composition in which the weight% and the dye are 30% by weight or less is preferable,
Moreover, the viscosity of the obtained ink is preferably about 2,000 cps (25 ° C.) or less.

A desired image is formed on the printing plate material by an inkjet method using the ink containing the photosensitive resin as described above, and these images may be solid images without halftone such as characters and figures, or may be monocolor. It may be a halftone dot image having a halftone like a photographic image, or a color separated image of two or more color images, such as cyan, magenta, and yellow color separated images (may be a halftone dot image), or various types of these. The combination of images may be used, and the type of image is not particularly limited. Further, the image formed as described above has a high resolution of 16 or more per 1 mm of the current various inkjet printers, so that 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) may be in accordance with conventionally known methods and conditions, such as an electron beam from an electron beam irradiation device, a high pressure mercury lamp, a medium to low pressure mercury lamp, a xenon lamp, and an arc. Lamps, ultraviolet rays generated from light sources such as metal halide lamps can be used, and irradiation time of a few seconds to a few minutes is sufficient.
The ink image is sufficiently crosslinked and cured.

The printing plate obtained by 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, a development method with heating or reduced pressure, and the like can be used.

Further, if necessary, the ink image can be colored, or the surface of the image area can be further treated with lipophilicity with a material having high lipophilicity, such as a tinctor.

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

(Operation / Effect) According to the present invention as described above, all steps such as image processing of a document, formation of an ink image by an inkjet method, and image curing processing are completed in a very short time, and an expensive material is used. Since there is no need to use it, there is no problem of complexity in process and cost.

Further, since the image formed on the plate has a high crosslink density and is formed of a very tough photosensitive resin, particularly an acrylate resin, it has a significantly higher printing durability than conventional toner images. It has printing capacity of several thousand to tens of thousands of sheets,
The problem of printing durability of the prior art has been solved satisfactorily.

Further, as a unique effect of the present invention, if the ink of the ink jet printer according to the present invention is matched with the printing ink, the color image of the ink jet printer becomes a proof, and it takes several hours to create a proof that currently requires several days. It can reach the user's hands without needing to speed up printing.

Next, the present invention will be described more specifically with reference to examples.
These examples are preferred examples of the present invention and do not limit the present invention in any way.

Reference Example 1 After converting a mono-color image formed on a TV screen into a halftone dot signal, a zinc oxide coated plate (manufactured by Fuji Photo Film Co., Ltd.) using an ink jet printer with an ink having the following composition
Printed out above.

Ink composition Polyvinylpyrrolidone 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 Methylcarbitol 5 parts by weight Holon 5 parts by weight Methyl isobutyl ketone 10 parts by weight The ink image was sufficiently cured by exposing it from a distance of 70 cm by a high pressure mercury lamp of 3 KW for 30 seconds to prepare a printing plate. This printed version has a screen frequency of 85
It accurately reproduced the 4-95% halftone dots of lines / inch.

When the above printing plate was placed on an ordinary simple offset printing machine and printing was performed with black ink, the ink inking property, halftone dot reproducibility, etc. were good and no disturbance of the printed image occurred even after printing 3,000 sheets. .

Example 1 A monocolor image formed on a high-performance television screen was converted into a halftone dot signal, and then printed with an ink jet printer using an ink having the following composition on a grained aluminum plate material having a thickness of 10 μm.

Ink composition Polyvinylpyrrolidone 10 parts by weight Pentaerythritol triacrylate 30 parts by weight Bis (hydroxyethylcarbamoylcyclohexyl)
Methanediacrylate 5 parts by weight Di-t-butyldiperoxyisophthalate 3 parts by weight 4- (4-butoxyphenyl) -2,6-diphenylthiapyrylium fluoroborate 4 parts by weight Glycerin 10 parts by weight Methylcarbitol 6 parts by weight Part Holon 5 parts by weight Methyl isobutyl ketone 15 parts by weight Next, the above ink image was exposed from a distance of 70 cm by a high pressure mercury lamp of 3 KW for 30 seconds to sufficiently cure the ink image to prepare a printing plate. This printed version has a screen frequency of 85
It accurately reproduced the 4-95% halftone dots of lines / inch.

When the above printing plate was placed on an ordinary off-wheel printing machine and printed with black ink, the ink receptivity, halftone dot reproducibility, etc. were good and no disturbance of the printed image occurred even after printing 30,000 sheets. .

Reference Example 2 A color image formed on a high-performance television screen is color-separated into yellow, red, blue, and black by a color scanner, and an ink having the following composition is used by the color-separation electric signal to print a zinc oxide coated plate on an inkjet printer. Ink composition in which each decomposed image was printed out in a dot pattern Polyvinylpyrrolidone 10 parts by weight Pentaerythritol triacrylate 40 parts by weight Di-t-butyldiperoxyisophthalate 3 parts by weight 4- (4-butoxyphenyl)- 2,6-Diphenylthiapyrylium fluoroborate 3 parts by weight Glycerin 10 parts by weight Methyl carbitol 10 parts by weight Methyl isobutyl ketone 10 parts by weight Next, each of the above ink images was taken at a distance of 70 cm for 3 KW.
The ink image was sufficiently cured by exposing it to the high pressure mercury lamp for 30 seconds to prepare a printing plate. When these four-color printing plates were applied to a normal off-wheel printing machine to perform color printing,
A color image having good ink receptivity and halftone dot reproducibility was obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Fukumoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-56-105960 (JP, A) JP-A-56 -113456 (JP, A) JP-A-62-179943 (JP, A)

Claims (1)

(57) [Claims] 1. An ink jet head is operated by an electric signal corresponding to an image signal, and a curable component selected from polyester acrylate, polyether acrylate, epoxy acrylate, alkyd acrylate and urethane acrylate is contained in an amount of 5 to 40% by weight and is reactive. Diluent
10-60 wt%, photoinitiator 0.1-10 wt%, solvent 1
A plate-making method comprising: forming an image by applying an ink having a composition of 0 to 80% by weight and a dye content of 30% by weight or less onto a printing plate material to cure the image portion by irradiation with light.