JPH0469245A - Forming of machine plate - Google Patents

Abstract

PURPOSE:To form machine plate having great plate wear, sufficient ink sticking property, and excellent waterproof by using lipophilic ink having heat curing component and treating with heat after recording so as to cure the ink component. CONSTITUTION:Lipophilic ink having heat curing component is used as ink for forming images on a recording material by an ink jet system. As preferable heat curing components, there are compounds such as isocyanate, epoxy, urethane, and a compound having ehtylene unsaturated bond capable of polymerization of two or more materials. Generally, in combination with those compounds, a heat curing agent, a thermal cross linking agent or a thermal polymerization initiator are preferably used. Thus, the eat curing component is indispensable in the lipophilic ink used for the present invention. In addition, appropriate coloring materials and solvents of the coloring materials can be used as other components of the ink. In this method, the recording material is treated with heat after recording by using the lipophilic ink with the ink jet system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of forming a printing plate. In particular, the present invention relates to a printing plate forming method for forming an image on a recording material using an inkjet method.

[Conventional technology and problems to be solved]

An image forming method using an inkjet method obtains a desired image by jetting ink, and when a printing plate is formed using this method, a highly accurate image can be obtained.

However, in the technology using the conventional inkjet method, there is a problem that printing plates formed with images using hydrophilic inks have low stiffness resistance. Alternatively, ink receptivity may be poor.

Therefore, it is possible to solve the above problem by adopting an inkjet method using lipophilic ink. (see publication),
However, printing plates that simply use oil-based ink generally have poor rigidity, making it difficult to put them into practical use and not solving the problem.

[Purpose of the invention]

In view of the above circumstances, the present invention aims to provide a method for forming a printing plate that has high rigidity, sufficient ink receptivity, and good water resistance.

[Means for solving problems]

The object of the present invention is to provide a method for forming a printing plate in which an image is formed by an inkjet method on a recording material that has been subjected to a hydrophilic treatment, using a lipophilic ink having a thermosetting component as an ink used in the inkjet method. This was achieved by a printing plate forming method characterized by performing heat treatment to harden the ink components after recording.

The present invention will be explained in more detail below.

The method for forming a printing plate of the present invention is to form an image on a recording material that has been subjected to a hydrophilic treatment using an inkjet method.

Any inkjet method can be adopted in carrying out the present invention; for example, the so-called electric field control method that uses electrostatic attraction to eject ink, or the so-called drop-on-demand method that uses the vibration pressure of a piezo element to eject ink. Various methods can be used, such as a pressure pulse method, a so-called thermal ink jet method in which ink is ejected using pressure generated by forming and growing bubbles using high heat.

The recording material used in the present invention has been subjected to hydrophilic treatment. In general, such a recording material can be obtained by hydrophilizing the surface of a substrate constituting the recording material. It can be obtained by making it hydrophilic by electrolysis or the like after polishing.

For example, the substrate of the recording material that can be used in the present invention includes an aluminum plate, a zinc plate, an iron plate whose surface has been treated with chrome plating, or a bimetallic plate such as a copper-aluminum plate, a copper-stainless steel plate, a brome-copper plate, etc. plates, or tri-metal plates such as chrome-copper-aluminum plates, chrome-copper-iron plates, chrome-copper-stainless steel plates, etc.
Hydrophilic conductive metal support, or paper or synthetic resin film whose surface has been treated with the above metal,
Alternatively, a conductive substrate having a hydrophilic surface such as a three-layer board in which a resin layer is sandwiched between metal plates such as aluminum is suitable.

In addition, especially in the case of a recording material substrate having an aluminum surface, surface treatments such as graining treatment, immersion treatment in an aqueous solution of sodium silicate, potassium fluorozirconate, phosphate, etc., or anodizing treatment are performed. Preferably, the aluminum plate is grained and then immersed in an aqueous sodium silicate solution as described in U.S. Pat. No. 2,714,066.
As described in Japanese Patent No. 5125, an aluminum plate which is anodized and then immersed in an aqueous solution of an alkali metal silicate can also be suitably used.

The surface of the aluminum layer is grained using hydrochloric acid, nitric acid,
This can be carried out by electrolytic polishing in an electrolytic solution such as sulfuric acid or phosphoric acid, or by mechanical polishing methods such as ball polishing, brush polishing, press polishing, honing polishing, etc.

The above anodic oxidation treatment can be performed using, for example, phosphoric acid, chromic acid, sulfuric acid,
This can be carried out by passing an electric current through an aluminum plate as an anode in an electrolytic solution of an inorganic acid such as boric acid, an organic acid such as oxalic acid or sulfamic acid, or an aqueous solution or a non-aqueous solution or a combination of two or more of these salts. .

The amount of oxide film formed by anodic oxidation is lO~50■
/ d m ” is preferable, and it is further preferable that a sealing treatment is performed using hot water, a silicate, a phosphate, a fluorosilicate, or the like.

A silicate electrodeposition treatment as described in US Pat. No. 3,658,662 is also effective.

Treatment with polyvinylphosphonic acid as described in DE 1,621,478 is also suitable.

These hydrophilic treatments also have the effect of making the surface of the support hydrophilic and improving ink coverage when an image is formed thereon by an inkjet method.

Next, in the present invention, a lipophilic ink having a thermosetting component is used as an ink for forming an image on the recording material by an inkjet method.

In the present invention, various conventionally known materials of this type can be used as the thermosetting composition that can be contained in the ink as a thermosetting component. Thermosetting compositions used include monomers, prepolymers, and polymers that chemically change their molecular structure within a short period of time when heated, increasing their physical strength or adhesion to the substrate. All of the compounds are included.

Thermosetting compositions that can be preferably used include incyanate compounds, epoxy compounds, urethane compounds, and compounds having two or more polymerizable ethylenically unsaturated bonds.

Such a compound is generally preferably used in combination with a thermosetting agent, a thermal crosslinking agent, or a thermal polymerization initiator.

Although it is essential that the lipophilic ink used in the present invention has a thermosetting component, an appropriate coloring agent and a solvent for the coloring agent can be used as other components for forming the ink.

As a solvent for dissolving dyes used as coloring agents, phosphoric acid triphenyl ester, N-cyclohexyl-p-
) Luenesulfonamide, p-hydroxybenzoic acid n-
Examples include heptyl, phenyl salicylate, and dicyclohexyl phthalate. These solvents have excellent affinity with dyes and exhibit extremely stable dye solubility in a molten state.

These dye solvents may be used alone or in combination with
By using more than one species in combination, it is possible to widen the allowable range of dye solubility, melting temperature, viscosity, etc.

The dye used as the coloring agent can be used without any particular restriction as long as it is an oil-soluble dye that is soluble in the above-mentioned solvent. For example, typical dyes include azo dyes, metal complex dyes, naphthol dyes, anthraquinone dyes, Indigo dyes, carbonium dyes, quinoimine dyes, cyanine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes,
Examples include nandoquinone dyes, naphthalimide dyes, perinone dyes, and phthalocyanine dyes. The colorant (dye) concentration in the ink is generally preferably 0.1 to 1.
0% by weight, and from the point of view of printing density and ink stability,
More preferably, it is 0.5 to 5% by weight.

Furthermore, in order to adjust various properties such as the melting temperature and viscosity of the ink, liquid plasticizers or Higher aliphatic alcohols, natural waxes, waxes such as higher fatty acids, stabilizers such as antioxidants, etc. may be used in combination.

Next, in the present invention, after recording on a recording material using a lipophilic ink by an inkjet method, a heat treatment is performed.

The heat treatment may be carried out by any means, and may be carried out using an appropriate heat source at a temperature depending on the thermosetting component used in the ink, and for a period of time to achieve desired curing.

When carrying out the present invention, it is preferable to perform the following lacquer treatment after the above heat treatment.

That is, in order to improve the rigidity of the printing plate, it is known that lacquer is applied to the image area. ) is preferable. As a lacquer, phenol or cresol formaldehyde resin and/or epoxy resin can be used as a base material. Other suitable materials for use in such lacquers include mixtures of homopolymers and copolymers of sulfur, tyrene, ortho-meta-1 or para-vinyltoluene, and indene units. Cyclohexanone or the like is preferably used as a solvent, and linseed oil can be used as a plasticizer. Examples of suitable lacquer compositions include, for example, British Patent Nos. 968706 and 1071163, and Canadian Patent No. 68.
It is described in the specification of No. 6284.

〔Example〕

Examples of the present invention will be described below along with comparative examples. However, it goes without saying that the present invention is not limited to the examples described below.

Example 1 In this example, an inkjet lipophilic ink prepared from the following materials was used.

After sufficiently dissolving the above components, the solution was filtered through a 0.5 μm membrane filter to obtain an inkjet ink.

In this example, a polypropylene sheet laminated with aluminum foil on both sides was used as the support for the recording material.
This was weighed, and a sheet whose surface had been made hydrophilic was used as a recording material.

That is, using the ink obtained above, recording was performed on the recording material using an on-demand inkjet printer.

Further, the recorded recording material was heated at 120° C. for 1 minute.

When the printing plate thus obtained was printed on a leaf offset printing machine, prints with sufficient image density were obtained from the 20th sheet onwards, and more than 50,000 prints with good images were obtained every 20 sheets.

Comparative Example 1 Inkjet recording was performed in the same manner as in Example 1, except that heating was not performed in Example 1, and a printing plate was created. When this comparative printing plate was printed on a printing press in the same manner as in Example 1, the ink in the image area began to separate from the support after about 2000 sheets were printed, and after that, some of the images were missing in the printed matter. I could only get it.

Comparative Example 2 An ink was prepared in exactly the same manner except that the ink composition of Example 1 was replaced with a commercially available water-soluble ink, and inkjet recording,
Heating was performed to create a printing plate.

When this comparative printing plate was printed on the same printing press as in Example 1, the ink receptivity was poor, and even after printing 100 sheets, printed matter with sufficient image density could not be obtained.

〔Effect of the invention〕

As mentioned above, according to the method of the present invention, the stiffness resistance is large;
It is possible to obtain a printing plate which has sufficient ink receptivity and also has good water resistance since a lipophilic ink is used.

Claims (1)

[Claims] 1. A method for forming a printing plate in which an image is formed by an inkjet method on a recording material that has been subjected to a hydrophilic treatment, using a lipophilic ink having a thermosetting component as the ink used in the inkjet method. . A method for forming a printing plate, which comprises performing a heat treatment to harden the ink components after recording.