JP2542501B2 - 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 lithographic printing, intaglio printing, letterpress printing, and silk screen printing have been widely used. These methods have been used for a long time, and are mainly used for factory mass printing.

The printing plate used in these printing methods forms a negative or positive mask pattern from an original, and exposes a printing plate material having a photosensitive resin layer through this mask pattern,
It is then developed into a printing plate. Particularly for full-color image printing, cyan, magenta, yellow and, if necessary, black plates are prepared, and the full-color image of the original is reproduced by these plates. .

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) In the case of mass printing described above, there is a problem that a large number of negative or positive films are inevitably used, and many materials such as a halftone dot filter are used. In addition, there are problems in that many proof printing operations are required in terms of color reproducibility and the like, and a large amount of film material is consumed, and as a result, many steps and a long time are required.

Further, among the above simple printing methods, the method of utilizing the electrophotographic method is a quick and simple method, but a toner image is formed on the zinc oxide coated sheet by the electrophotographic method, and the printing plate (offset Since it is used as a master), the toner image does not have sufficient strength with respect to the printing ink, resulting in 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.

Accordingly, there is a demand for a technique capable of providing a printing plate which can easily and easily make a plate and has high printing durability in a small factory or various offices as well as in the case of mass printing.

(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, the present invention operates an inkjet head by an electric signal corresponding to an image signal to apply a water-based ink that affects the photosensitivity of the photosensitive resin layer onto a printing plate material having the photosensitive resin layer. To form a relief image by exposing with a water-based developer and then developing with a water-based developer.

Next, the present invention will be described in more detail. The method of the present invention basically comprises the following three steps, and in particular, the remarkable effect that the production of a large number of negative or positive image films as in the prior art can be omitted. Play.

(1) A process of converting a document 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 perform the above process on a printing plate material having a photosensitive resin layer. A process of forming an ink image by applying a water-based ink that affects the photosensitivity of the photosensitive resin layer, (3) a process of exposing a printing plate material having an ink image and then developing it with a water-based developer.

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 ink jet head is operated according to the image signal in the step (1) to apply a water-based ink to form a desired ink image on the printing plate material having the photosensitive resin layer. Any ink jet method may be used as long as it is an ink jet method for forming an ink image, and is not particularly limited.

In the case of mass printing, the printing plate material is a conventionally known planographic printing plate,
Any plate material used for intaglio, letterpress, silk screen plate, etc. can be used, and a photosensitive resin layer used in these plate making techniques may be provided on these plate materials. Plate material provided with a conductive resin layer, for example PS
A plate or the like can also be preferably used. For simpler printing,
Any conventionally known offset master plate material coated with zinc oxide, any material provided with a photosensitive resin layer on a waterless planographic material coated with a silicone compound, and the photosensitive resin layer is It may be one that can be cross-linked and cured by light irradiation, or conversely, one that can be decomposed and eluted by light irradiation. Further, a plate material whose non-image area changes to hydrophilic by exposure may be used, and examples thereof include an o-quinonediazide compound, spiropyrans, a combination of an amino compound and carbon tetrabromide,
A plate material coated with a high molecular weight fluorocarbon compound may be used.

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

Further, in the offset printing plate using the water-based ink, it is necessary that the non-image area be changed from hydrophilic to lipophilic after exposure. Many materials with such properties are known, but, for example, a method in which an initiator such as dichromate is added to the gelatin layer to make it hydrophobic by exposure or a boehmite heptahydrate film is formed. Then, there is a method of changing it to be hydrophobic by exposure treatment.

For letterpress, a combination of gelatin and photoinitiator,
In addition to generally known photosensitive resins such as a combination of an o-quinonediazide compound and a binder, there are polymer compounds and polymer carbonyl compounds crosslinked with an organic titanium compound.

As described above, the printing plate material used in the present invention may be any printing plate material provided that a photosensitive resin layer is provided in advance on the surface thereof, and an appropriate one may be selected from conventionally known plate materials. Good.

The main feature of the present invention is that an image is formed on any plate material as described above by an inkjet method with an aqueous ink containing a component that affects the photosensitivity of a photosensitive resin layer of a printing plate material, and This is the point of development after exposure using a water-based developer.

The ink used in the present invention is an aqueous ink containing a component that inhibits, reduces or eliminates the photosensitivity of the photosensitive resin layer provided on the printing plate.

For example, when the photosensitive resin layer is one that crosslinks and cures upon exposure to form a coating film that cannot be eluted, it absorbs or reflects the light that is exposed to light so that the photosensitive resin layer is not crosslinked and cured. It inhibits according to the image. Examples of components having such an action include dyes that absorb light such as black pigments, materials that reflect light such as white pigments, and materials that absorb light such as ultraviolet absorbers such as alkali and acid. The water-based ink contains a material that acts on the cross-linking agent of the photosensitive resin layer to eliminate the effect of these cross-linking agents.

By forming a desired image on the photosensitive resin layer with an ink jet method using such an ink and exposing it, when the photosensitive resin layer is made of a photo-curable resin, only the ink image portion is cross-linked and cured. However, since the other part is crosslinked and hardened and cannot be eluted, by the next development processing,
A relief image is formed which can be used as a printing plate.

Further, when the photosensitive resin layer is a decomposable type photosensitive resin layer that can be eluted by exposure, the exposure of the image portion of the ink is blocked. It becomes a relief image of.

Further, if the photosensitive resin layer becomes hydrophilic by exposure, only the ink image portion remains oleophilic, so that a lithographic printing plate can be obtained.

As described above, the ink used in the present invention is different from the conventional inkjet ink only in that the ink contains a material having the above-mentioned specific action, and other than the conventionally known inkjet ink. It's good. For example, the ink medium may be water or a mixture of water and a hydrophilic organic solvent.

Examples of materials that affect the photosensitivity of the photosensitive resin layer by absorbing or reflecting light include black pigments such as carbon black, various black dyes, white pigments such as titanium oxide and zinc oxide, water-soluble or Oil-soluble UV absorber,
An acid such as an organic acid or an inorganic acid, an alkali such as an amine or a hydroxide of an alkali metal, or the like is selected and used according to the photosensitivity of the photosensitive resin layer. If these light absorbing or light reflecting materials are present in the ink at a concentration of about 0.5 to 20% by weight, sufficient effects can be obtained.

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 a binder,
Natural resins such as shellac and casein, and styrene-
Polymers such as 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 viscosity of the obtained ink is preferably about 1,000 cps (25 ° C) or less.

A desired image is formed on the printing plate material by the ink jet method using the ink as described above, and these images may be solid images without halftone such as characters and figures, or like monocolor photographic images. It may be a halftone halftone image, a color separated image of two or more color images (for example, cyan, magenta, yellow, or the like) (may be a halftone image) or a combination of these various images. The type of image is not particularly limited. In addition, the image formed as described above is a very high resolution image because various inkjet printers at present have a high resolution of 16 or more per 1 mm,
There is no particular problem in terms of resolution.

The exposure method itself in the step (3) may be in accordance with conventionally known methods and conditions, such as ultraviolet rays generated from a light source such as a high pressure mercury lamp, a medium to low pressure mercury lamp, a xenon lamp, an arc lamp, and a metal halide lamp. Any of these can be used, and irradiation time of a short time of several seconds to several minutes is sufficient.

As the developing method, a developing method using an aqueous developer such as elution with alkaline water or elution with water can be used.

Further, if necessary, the formed relief image can be colored, or the surface of the image area can be further treated with lipophilicity by a highly lipophilic material 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 the steps such as image processing of a document, formation of an ink image by an inkjet method, exposure and development are completed in a very short time, and many of the conventional techniques are used. Since there is no need to use any film for masks or the like, there is no problem of process complexity and cost.

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.

Example 1 An offset PS plate (manufactured by Fuji Photo Film Co., Ltd.) was used by an inkjet printer after converting a monocolor image formed on a TV screen into a halftone dot signal and using an ink having the following composition.
I printed out the image above.

Ink composition Water 80 parts Glycerin 15 parts Methyl carbitol 5 parts Carbon black 5 parts Next, the above PS plate entire surface is exposed from a distance of 70 cm by a high pressure mercury lamp of 3 KW for 30 seconds to sufficiently cure the photosensitive resin layer, A developer "Developer mesh # 985A" (manufactured by Fuji Photo Film Co., Ltd.) was used for development to prepare a printing plate. This printing plate accurately reproduced 4-95% halftone dots with a screen ruling of 85 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 30,000 sheets. .

Example 2 The same ink image as in Example 1 was formed by operating an inkjet head on the relief printing plate material “NAPP-40PAN-Y” (manufactured by Nap Systems, Inc., USA). Next 3KW
The high-pressure mercury lamp was subjected to light reflection from a distance of 70 cm for 30 seconds, and elution treatment was performed with warm water at 40 ° C. The relief printing plate thus obtained accurately reproduced 4-95% halftone dots with a screen ruling of 85 lines / inch.

Example 3 After converting a monocolor image formed on a high-performance TV screen into a halftone dot signal, an ink jet printer was used to prepare a 10% aqueous solution of gelatin and a 10% alcohol solution of tetraisobutyroxytitanium, etc. The images were printed out on a 100 μm thick grained aluminum plate material which had been mixed and coated in a quantity and dried in a dark room.

Ink composition Water 80 parts Glycerin 15 parts Methyl carbitol 5 parts Carbon black 3 parts Ultraviolet absorber (Ubinal D50) 0.3 parts Next, the above plate material is exposed for 20 seconds from a distance of 70 cm by a high pressure mercury lamp of 3 KW to non-image. The cross-links of the part were cleaved. Next, when it was developed by ultrasonic treatment in water, a printing plate was prepared in which the image area remained as it was and the non-image area was eluted. This printing plate has a screen frequency of 85 lines / inch.
~ 95% halftone dots were reproduced accurately.

When the above printing plate was placed in an ordinary printing machine and printing was performed with black ink, the ink inking property, halftone dot reproducibility and the like were good, and the printed image was not disturbed even after printing 30,000 sheets.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Hiroshi Fukumoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-50-85404 (JP, A) JP-A-56 -105960 (JP, A) JP-A-60-245587 (JP, A)

Claims (3)

(57) [Claims] 1. An ink jet head is operated by an electric signal corresponding to an image signal to apply a water-based ink that affects the photosensitivity of the photosensitive resin layer onto a printing plate material having the photosensitive resin layer. A plate-making method comprising forming an image, exposing it, and then developing with an aqueous developer to form a relief image. 2. The plate-making method according to claim 1, wherein the image formed by the ink is light absorbing. 3. The plate-making method according to claim 1, wherein the image formed by the ink is light reflective.