JPS6020199B2 - Thermal recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-sensitive recording method using a V-thermal recording material having an improved heat-sensitive layer, and more particularly to a heat-sensitive recording method that does not cause fogging.

Thermal recording materials do not need to be handled in a dark room or under safe light as do silver halide photographic materials, and are generally similar to silver halide photographic materials, such that the image forming process can result in an immediately visible image, for example by application of a thermal pattern. A number of V-thermal recording materials and methods have been proposed as being faster and easier than photosensitive materials and therefore suitable for a wide variety of practical purposes.

For example, Hakama Kosho No. 44-19718 proposes increasing the swelling degree and dissolution rate in water of the recording portion of a thermal recording layer containing gelatin as the main ingredient.

Further, Japanese Patent Publication No. 46-27919 describes a method of selectively removing heated portions of a heat-sensitive layer by washing or rubbing with a liquid that selectively permeates the heated portions. On the other hand, in Hakamako No. 44-22957,
A heat-sensitive layer containing a light-absorbing material that converts absorbed light into heat and hydrophobic thermoplastic polymer particles dispersed in a hydrophilic binder in a ratio greater than 1:1 is exposed to produce a hydrophilic, water-permeable layer. A method for obtaining images based on differences in water solubility and water solubility is described.

These recording materials include xenon lamps, halogen lamps,
Contact exposure can be performed using a tungsten lamp or the like as a light source.

However, when contact exposure is performed using a light source such as the one described above, if the heated portion of the material becomes insolubilized, the temperature will rise even to the non-exposed portion of the recording material due to heat conduction from the image area of the original image.
Even after development, the heat-sensitive layer may remain in non-image areas, causing fog.

Conversely, heat may be conducted from the heated portion to the non-image portion of the original, and a large amount of energy may be required for insolubilization.

Similarly, with materials that become solubilized in heated areas, the temperature in the exposed areas may not rise sufficiently, resulting in fogging, or the temperature in the non-exposed areas may rise, increasing solubility and making it impossible to obtain a sufficient image. .

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a heat-sensitive recording method that prevents heat conduction from the original image and is less likely to cause fogging.

Other objects of the invention will become apparent from the following description of the specification.

The above-mentioned object of the present invention is to provide a heat-sensitive recording method using a heat-sensitive recording material having a heat-sensitive layer on a support whose solubility in a developing solution or oil swelling property is changed by heating with a light beam, in which the uppermost layer has a rough surface. The heat-sensitive layer of the heat-sensitive recording material, which has a surface roughness of 2.0 French or less in terms of center line average roughness and is roughened to inhibit heat conduction from the original image. This is achieved by a heat-sensitive recording method characterized in that the original image is superimposed on the layer side and contact exposure is performed.

One of the major features of the present invention is that it not only achieves the above object, but also uses a heat-sensitive recording material having a roughened heat-sensitive layer of the present invention, and performs contact exposure by superimposing an original image on the heat-sensitive layer side. Even when suction is used in this way, it is possible to prevent heat conduction from the original image and prevent fogging, and the suction is applied evenly, covering the entire surface of the heat-sensitive recording material in a short time. The scales are in close contact with the original painting.

The heat-sensitive recording material used in the present invention has a heat-sensitive layer in which the uppermost layer of the constituent layers on the support has a rough surface, and the surface roughness of the heat-sensitive layer is 2.0 French or less in terms of center line average roughness. The surface is roughened to inhibit heat conduction from the original painting.

As the support, a dimensionally stable plate-like material can be suitably used.

Supports used in the present invention include paper, paper laminated with plastic (e.g. polyethylene, polypropylene, polystyrene, etc.), metal plates made of aluminum, zinc, copper, etc., cellulose diacetate, cellulose triacetate,
Cellulose propionate, cellulose butyrate, cellulose acetate/butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene,
Examples include plastic films such as polycarbonate and polyvinyl acetal.

Among these supports, polyethylene terephthalate,
Paper laminated with polyethylene or aluminum plate is preferred. The support is surface-treated if necessary.

For example, the aluminum plate is preferably subjected to surface treatment such as graining treatment, immersion treatment in an aqueous solution of sodium silicate, thermalized potassium zirconate, phosphate, or the like, or anodization treatment. In the case of a support having a plastic surface, the surface is preferably subjected to a surface treatment such as chemical treatment, electric discharge treatment, flame treatment, ultraviolet treatment, high frequency glow discharge treatment, or activated plasma treatment. Further, between the support and the V heat-sensitive layer, if necessary, an intermediate layer made of gelatin, casein, polyvinyl alcohol, ethyl cellulose, phenol resin, diazoresin, styrene-maleic anhydride copolymer, polyacrylic acid, etc. It can be provided for the purpose of improving adhesion between the support and the heat-sensitive layer or preventing pinholes. As the heat-sensitive layer of the present invention provided on the support, any layer can be used as long as its solubility in a developer or swelling property changes when heated by light exposure.

Preferred materials include a heat-sensitive recording material having a heat-sensitive layer using gelatin (Japanese Patent Publication No. 44-9718), a heat-sensitive recording material having a heat-sensitive layer containing a novolac type phenol resin and carbon black (Samurai Iso-Sho No. 54-144337), etc. It is. These are useful as positive heat-sensitive recording materials that become soluble when heated. Also, heat-sensitive recording materials containing thermoplastic polymer particles in a hydrophilic binder (Japanese Patent Publication No. 44-2295
No. 7), a heat-sensitive recording material using a resol-type phenolic resin (Special Warabi Sho 54-1144338), and the like are useful as negative-tone heat-sensitive recording materials that become insoluble when heated. Particularly preferred is a heat-sensitive recording material having a heat-sensitive layer containing an ionomer resin (see JP-A-56-148 Magnetic Needle).

That is, a preferred specific example in this case is an ionomer resin. - A copolymer of olefin (especially ethylene) and 〇,3-unsaturated carboxylic acid (especially acrylic acid or methacrylic acid) is combined with metal ions (especially N, Mg+, Z
The resin is ionically crosslinked with nH), and
This heat-sensitive layer contains a water-soluble polymer compound (preferably polyvinyl alcohol, particularly preferably one containing 85 to 90% vinyl alcohol units) as a binder, and furthermore contains an ionomer resin and a water-soluble polymer The ratio of molecular compounds is 2:3 to 9:1 by weight. The basic structure of the V heat-sensitive recording material used in the present invention is one having a heat-sensitive layer as described above on a support.
A heat-sensitive intermediate layer can be provided between the heat-sensitive layer and the support.

Specifically, there is one described in Japanese Patent Publication No. 45-3 Ban 3y. It is desirable to use an ionomer resin for such an intermediate layer as well. The present invention can be applied to any of the above-mentioned heat-sensitive recording materials, and any means or method for roughening the above-mentioned V heat layer is arbitrary.

According to a preferred embodiment of the invention, the top layer of the heat-sensitive recording material is a heat-sensitive layer that is mechanically matted or contains a matting agent. Here, as a matting agent,
Silicon dioxide, zinc oxide, titanium oxide, zirconium oxide, glass particles, alumina, starch, polymer particles (e.g. particles of polymethyl methacrylate, polyethylene, phenolic resins, etc.) and U.S. Pat. No. 2,701,24
The matting agents described in the specifications of No. 5 and No. 2,992,101 are included. Two or more of these can also be used in combination. Methods for mechanically matting the surface of the heat-sensitive layer include [11] Coating the heat-sensitive layer so as to obtain a coating layer consisting of an uneven pattern, and {2] Mechanically roughening the surface after coating the heat-sensitive layer. There is a method for obtaining a heat-sensitive layer having an uneven pattern.

As a specific example, m can be obtained by applying the uppermost layer of the heat-sensitive layer with a roller having projections and depressions. on the other hand,
(As a specific example of 2), after a heat-sensitive layer is provided, fine particles having a hardness higher than that of the heat-sensitive layer are applied to a sheet with a smooth surface such as paper, cloth, or plastic film, and the matrix is used as the matrix. There are methods such as matting by applying pressure with a pressure roller.In the heat-sensitive recording material according to the present invention, the surface roughness of the V heat-sensitive layer surface is 2.0 mm or less in terms of center line average roughness, and The surface is roughened to inhibit heat conduction.

In particular, the centerline average roughness is preferably 0.3r to 2.0mm. If the surface roughness is 0.3 mm to 4 mm, the insulation effect will not be sufficient. Further, if the value is larger than 2.0 French, the contact with the original painting may be incomplete and a clear image may not be obtained. When a matting agent is used, the diameter of the particles of the matting agent can be appropriately selected in relation to the thickness of the thermal layer.

When such a matting agent is contained in the V heat-sensitive layer, it is a historical practice to disperse the matting agent in a coating solution for the heat-sensitive layer and apply it onto the support.

When contact exposure is performed on the heat-sensitive recording material according to the present invention,
No special measures are required due to the roughened thermal layer. The heat-sensitive recording material according to the present invention can be subjected to contact exposure using a xenon lamp, halogen lamp, tungsten lamp, etc. as a light source, but preferably the light emission time is about 1/100 seconds or less and the light intensity in the infrared region is A flash light source that is large is preferred.

The V heat-sensitive recording material of the present invention has industrial advantages such as being able to obtain a high-resolution paste film at a low cost and also being able to obtain a lithographic master.

According to the present invention, an image with excellent developability can be obtained without producing capri in non-image areas.

Further, there is an advantage that the vacuum contact time is shortened. EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the embodiments of the present invention are not limited thereby. Example 1 A composition according to the above weight ratio was dispersed with glass beads for 3 minutes and then dispersed with a wire bar onto a 100 um thick polyethylene terephthalate (PET) film having a gelatin subbing layer to a dry weight of about 40 ml. The sample of the present invention was obtained by applying the coating so as to give a coating temperature of /d and dry burning at 50° C. or lower.

The surface structure of the sample of this invention was measured using a perometer.
When measured in terms of tsubo (manufactured by Penher), the center line average height [Ra] was 0.8 mm.

A negative original was placed on this sample of the present invention, and a xenon flash light source (manufactured by Riso Kagaku Kogyo ■, RISOTORAPENUP) was used.
FX-120), 0. Exposure to phantom/earth energy.

Next, the above-mentioned sample of the present invention was immersed in water and rubbed with a sponge to completely dissolve and remove the unexposed portion, resulting in a clear black positive image without fog.

Comparative Example 1 The same composition was used as in Example 1 except that the aqueous polymethyl methacrylate dispersion was removed, and the dispersion, coating, and drying were carried out in the same manner as in Example 1.

The surface roughness of this comparative recording material was measured in the same manner as in Example 1, and the center line average paper size [Ra] was 0.1 peak.

When this comparative recording material was exposed and developed in the same manner as in Example 1, mottled fog remained in the non-image areas. Example 2 The composition according to the above weight ratio was dispersed for 30 minutes using glass beads, and applied onto a polyethylene terephthalate film having a gelatin undercoat layer with a thickness of 100 mm using a textured roller, dried at 50 mm or less, and then A sample of the invention was obtained.

The coating amount was approximately 25 phosphorus/d after drying. The surface roughness of this sample of the present invention was measured in the same manner as in Example 1, and the center line average roughness [Ra] was 1.0.

When this sample of the present invention was exposed and developed in the same manner as in Example 1, the unexposed areas were completely dissolved and removed, and a clear black image without capri was obtained. Comparative example 2LIOFAST
BLACKM-232 2 animals Weight part Copole
MLatexL-2000 2 parts by weight 10
% Gohsenol GL-05 aqueous solution 3 parts by weight Polymethyl methacrylate particles (average particle size 50 mounds) 2 parts by weight Water 3 parts by weight The composition with the above weight ratio was dispersed between 3 pieces using glass beads, and a gelatin undercoat layer was formed. The recording material was coated onto a polyethylene terephthalate film having a thickness of 100 layers using a wire bar so that the weight after drying was about 40 mm/d, and this recording material was dried for less than 50 mm to obtain a sample.

The surface roughness of this recording material sample was measured in the same manner as in Example 1, and the center line average roughness [Ra] was 3.0 peaks.

When this sample was exposed and developed in the same manner as in Example 1, a black image without fog was obtained.

Claims (1)

[Claims] 1. In a heat-sensitive recording method using a heat-sensitive recording material having a heat-sensitive layer on a support whose solubility or swellability in a developing solution changes when heated by light exposure, the uppermost layer has a rough surface. The heat-sensitive layer of a heat-sensitive recording material, wherein the heat-sensitive layer has a surface roughness of 2.0 μ or less in center line average roughness and is roughened to inhibit heat conduction from the original image. A thermal recording method characterized by the fact that the original picture is superimposed on the side and close exposure is performed. 2. The heat-sensitive recording method according to claim 1, wherein the heat-sensitive layer contains a matting agent. 3. The heat-sensitive recording method according to claim 1 or 2, wherein the heat-sensitive layer is formed by coating with an uneven roller.