JPS61169872A - Image forming method - Google Patents

Abstract

PURPOSE:To execute easily production and recording without exercising special care for thermosensitivity and to make possible the long-term stable preservation of an image by using a recording material constituted by providing a conductive layer on a substrate and forming a specifically constituted thermosensitive layer thereon. CONSTITUTION:The recording material 10 is formed by forming the conductive layer 1 consisting of a metallic plate of gold, platinum, copper, etc. on the insulating substrate 2 consisting of a resin film, etc. and depositing the thermosensitive layer 3 constituted of a polymer complex composed of a basic polymer such as N-vinyl pyrolidone and acidic polymer such as citric acid and a sensitizer thereon. An original 5 is placed thereon and is processed by a heat pattern 4 to form a latent image. Such material is immersed into an electrolyte 6 and electricity is conducted thereto to develop the image. The production and recording are thus easily executed without exercising special care for the thermosensitivity and the long-term stable preservation of the image is made possible.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method of recording various information and forming a visible image by thermal pattern processing.
A heat-sensitive layer consisting of a polymer complex of a specific composition is formed on a conductive substrate of a specific composition, a latent image is formed in the heat-sensitive layer by thermal patterning, and the latent image is easily developed by electrochemical means. The purpose is to provide a method that can be used to visualize images.

(Prior Art) Many methods have been known for recording various types of information using thermal patterns. By applying a thermal pattern to these heat sensitive layers, a recorded image is formed which is readable by a visible change or other reading means in the heat sensitive layer. Heat-sensitive materials are often used to form the heat-sensitive layer, and many of these materials are various polymers, pigments, or mixtures thereof.

(Problem to be Solved by the Invention) In many cases, heat-sensitive polymers and dyes are used to form the heat-sensitive layer of the recording material used in the conventional recording method using thermal patterns as described above. When forming a heat-sensitive layer from these materials, there is a problem in that sufficient care must be taken in handling these materials.

That is, in order to form heat-sensitive layers from heat-sensitive materials, those materials must be rendered heat-insensitive before use, and for similar reasons, preservation of the recording material after formation requires even more adequate protection. If care is not taken, there is the problem that it loses its heat sensitivity before use, rendering it unusable.

In addition, even with such various precautions, conventional recording materials using thermal patterns still have problems with the storage stability of recorded materials after recording, and are not reliable enough in terms of long shelf life. It wasn't.

Therefore, there is a need for a recording material and a recording method that do not require special precautions during production, can easily form a heat-sensitive layer, can easily record information, and can stably store recorded information for a long period of time. The reality is that it is convenient and strongly requested.

In order to meet the demands of the prior art as described above, the present inventors
As a result of extensive research, we have found that when a conductive substrate with a specific configuration is used as the supporting base of the recording material, and a polymer material with a specific configuration is used as the material constituting the heat-sensitive layer, various types of information can be easily transferred to the substrate by heat. The present invention was completed based on the discovery that a recorded image with excellent storage stability can be obtained by recording a pattern and by converting the latent image of the recorded information into a visible image using specific electrochemical means. It is Tachino.

(Means for Solving the Problems) That is, the present invention comprises a substrate and a heat-sensitive layer provided on the substrate, and the substrate comprises a metal layer or a conductive metal oxide layer provided on an insulating substrate. , and a recording material in which the heat-sensitive layer is made of a polymer complex of a basic polymer and an acidic polymer is thermally patterned to form a latent image, and then immersed in an electrolytic solution using the recording material as one electrode, This is an image forming method that involves applying electricity to develop a latent image portion.

To explain the present invention in detail, 1. The main features of the present invention are as follows:
The first feature is that a conductive substrate with a specific configuration is used as the substrate of the recording material used, and the second feature is that a specific polymer complex is used to form the heat-sensitive layer. The third feature is that electrochemical means are employed to develop the latent image produced by thermally patterning the thus formed recording material using a conventional method.

Therefore, the present invention will be further described in detail focusing on these main features.

In the present invention, any insulating substrate 1 such as a glass plate, various resin films or sheets can be used as the substrate of the recording material, and the metal layer formed on these insulating substrates can be , for example, gold,
The conductive metal oxide layer can be formed from metals such as platinum, silver, nickel, copper, etc. by conventionally known techniques such as vapor deposition, and conductive metal oxide layers can be formed using metals such as tin oxide, indium oxide, indium-tin oxide, etc. It can similarly be formed from conductive oxides such as.

The polymer complex used to form the heat-sensitive layer on the conductive layer is composed of a basic polymer and an acidic polymer.
The basic polymer itself is already known in Japanese Patent No. 744, and includes, for example, the following.

N-vinylpyrrolidone, N-vinyl-3-methylpyrrolidone, N-vinyl-5-methylpyrrolidone, N-vinyl-3,3,5-trimethylpyrrolidone, N-vinyl-3
-Benzylpyrrolidone, N-vinylpiperidone, N-vinyl-4-methylpiperidone, N-vinyl-caprolactam, N-vinylpyrrolidone, N-vinyl-3-
Morpholine, N-vinylthiopyrrolidone, N-vinyl-
Homopolymers such as 2-pyridone or random copolymers, block copolymers, graft copolymers, etc. with other common monomers: N-vinyl-2-oxazolidone, N-vinyl-5-methyl-2 -Oxazolidone, N-vinyl-5-ethyl-
2-oxazolidone, N-vinyl-4-methyl-2-oxazolidone, N-vinyl-2-thioxazolidone,
Homopolymers such as N-vinyl-2-mercaptobenzothiazole or random copolymers, block copolymers, graft copolymers, etc. with other common heptadol; N-vinylimidazole, N-vinyl- Homopolymers such as 2-methylimidazole and N-vinyl-4-methylimidazole, or random copolymers, block copolymers, graft copolymers, etc. with other common monopolymers; 2- or 4- Homopolymers such as vinyl pyridine, random copolymers, block copolymers, graft copolymers, etc. with other common monomers are mentioned, and other copolymerizable monomers that may be used in the above include: Methacrylate, acrylate, acrylamide, acrylonitrile, vinyl ether, vinyl acetate, vinyl imidazole,
Ethylene, styrene and other common heptamers, etc., and those particularly useful in the present invention are N-vinylpyrrolidone, N-vinylpiperidone, N-vinylcaprolactam, N-vinylmorpholine, N-vinyl-2-oxacylidone, These are homopolymers and copolymers of N-vinyl-5-methyl-2-oxacylidone. In the case of a copolymer, it is preferable that the above-mentioned nitrogen-containing monomer is included in an amount of 50 mol % or more.

Furthermore, examples of acidic polymers that can form polymer complexes with the above basic polymers include the following.

Polyesters with terminal carboxyl groups obtained by reacting polycarboxylic acids such as citric acid, tartaric acid, and phthalic acid with polyhydric alcohols such as ethylene glycol, 1.4-butanediol, and diethylene glycol in excess of acid; various polycarboxylic acids Acidic cellulose derivative modified with (
(Refer to Japanese Patent Publication No. 35-5093): Homopolymers of polycarboxylic acids such as vinyl ether ester monomers or random copolymers with other common monomers, blower
graft copolymers, etc. (Japanese Patent Publication No. 35-849)
(Refer to Publication No. 5) Heptamer homopolymers such as nialic acid or methacrylic acid or random copolymers with other common monomers,
Block copolymers, graft copolymers, etc.: Homopolymers of α,β-unsaturated vinyl monomers such as anhydrous malemonojo, itaconjo, etc., or random copolymers and block copolymers with other common heptadons. Polymers, graft copolymers, etc.: Homopolymers of monomers containing other sulfone or phenol groups, or random copolymers, block copolymers, graft copolymers, etc. with other common monomers; Other carboxyl Acidic modified products of various polymers with compounds containing groups, sulfonic acid groups, or phenol groups: Any of the above acidic polymers can be used, but particularly preferred in the present invention are α,β-unsaturated acid polymers. These include homopolymers, random copolymers, block copolymers, and graft copolymers, and particularly preferred is a copolymer of alkyl vinyl ether and maleic anhydride.

The present inventor has been conducting various research on mixtures of basic polymers and acidic polymers as described above, and found that
By mixing these polymers in a solution, both polymers interact in some way and form a polymer complex that is different from either polymer.
If both polymers are mixed in a relatively good solvent, a polymer complex will precipitate, and if mixed in a relatively good solvent, a significant increase in viscosity will occur, which is different from a simple mixture of both polys used. It was discovered that it has the following properties.

Therefore, the polymer complex used in the present invention means a polybu complex made of the above-mentioned polymers. In the present invention, a preferred product is one formed by mixing both polymers in such a proportion that their basicity and acidity are approximately the same, and such a mixing ratio is determined based on the basicity and acidity of both polymers. The mixing ratio of the two can be determined accordingly, and the polymer complex formed by mixing the two in an appropriate ratio will not be strongly dyed by acid dyes or basic dyes. It becomes a polymer complex that is not oxidized. Therefore, the mixing ratio of both polymers can be determined using these factors.

It was obtained as described above. Polymer complexes generally do not dissolve in relatively good solvents such as water, alcohols, esters, hydrocarbons, etc., so by dissolving both polymers in these poor solvents and mixing the two warm liquids, Polymer complexes for use in the present invention can be isolated. Alternatively, a solution of the polymer complex can be obtained by mixing in a relatively good solvent such as dimethylformamide, dimethylacetamide, dimethylsulfoxide, or the like. Therefore, when forming a heat-sensitive layer on the conductive substrate as described above using the polymer complex as described above.

(1) Create solutions of both polymers,
A method of applying one of the solutions onto a substrate and then applying a predetermined amount of the other polymer solution thereon to form a polymer complex on the substrate; (2) using a relatively good solvent as described above; A method of preparing a solution of a polymer complex and applying it onto a substrate can be used.

The recording material used in the present invention is formed using the above-mentioned materials, but in the present invention, in addition to the above-mentioned materials, for example, thermoplastic polymers other than those described above may be used in combination with the above-mentioned polymer complex. They may enhance their film-forming ability, or they may include small amounts of colorants to give their films a light color.

Next, the present invention will be described in more detail with reference to the accompanying drawings that schematically illustrate the structure of the recording material used in the present invention. FIG. 1 diagrammatically shows the structure of the recording material 10 of the present invention with its cross-sectional shape, where 1 represents a metal layer or a conductive metal oxide layer as described above, and 2 represents an insulating substrate. 3 shows a heat-sensitive layer made of a polymer complex. FIG. 2 is a schematic cross-sectional view of a recording material of another embodiment.

As shown in FIGS. 1 and 2, recording material 10 used in the present invention
The thermosensitive layer 3 made of the above-mentioned polymer complex is formed on the surface of the conductive layer 1. As shown in FIG. 1, if a conductive layer 1 is formed on both sides of an insulating substrate 2, a heat-sensitive layer 3 is formed on both sides.
The recording material 1O has the following properties.

The conductive layer l used may have the same shape as the substrate 2 or may have a smaller area, and its thickness is generally about 0.0
Approximately 5 to 0.51 Lm is suitable, and the substrate 2 is
Technically, it may have any thickness and any shape, but generally a plate, sheet, or film with a thickness of about 0.03 to 3 a+m is preferable, and the shape depends on the recording material to be obtained. Depending on the purpose of use, any shape,
For example, the heat-sensitive layer 3 may be formed in the form of a tape or the like.Also, the heat-sensitive layer 3 may be formed by a one-liquid method or a two-liquid method as described above, but its thickness is generally about 0.11-1 OIL. suitable.

The inventors of the present invention have discovered that although the surface of the substrate of the recording material formed as described above is conductive, the recording material as a whole becomes a poor conductor and loses good conductivity.

This was naturally predictable since the two types of polymers that make up the polymer complex forming the heat-sensitive layer are mutually neutralized, but further detailed research by the present inventor revealed that found that when these heat-sensitive layers are treated with a thermal pattern having more energy than the surrounding atmosphere, only that part of the heat-sensitive layer becomes conductive again, that is, a latent image consisting of conductive regions is formed. This is what I did. Moreover, such latent images retained their electrical conductivity for several minutes to several days after application of the thermal pattern was discontinued, and then returned to their original insulating properties.

As for the method of recording information and forming a latent image by exposing the recording material to a thermal pattern as described above, any conventionally known method can be used.For example, as schematically shown in FIG. , a thermal stylus, a thermal type, a mechanical method that locally and selectively heats the heat-sensitive layer of a recording material by scanning thermal energy4 such as a thermal printing head or a laser beam or an electron beam, or a radiation-absorbing character. Any other method may be used, such as a radiant heating method in which a document having a pattern (not shown) and a recording material are placed one on top of the other in a thermally conductive position, and intense radiation is applied using an incandescent tungsten lamp or the like.

As described above, the desired latent image 5 is formed in the heat-sensitive layer of the recording material used in the present invention, but the recording material of the present invention can be developed into a visible image as follows. Such a developing method is also an important feature of the present invention.

A method for developing the latent image formed as described above will be specifically explained with reference to the accompanying drawings.

FIG. 4 schematically shows a method for developing the latent image 5 formed on the recording material IO used in the present invention, and FIGS. 5(A) and 5(B) show the developed recording material. 1 schematically shows a cross section of a material 10. FIG.

As shown in FIGS. 4 and 5, one preferred method for developing is to soak the recording material 10 on which these latent images have been formed in an electrolytic solution 6.
By immersing it in the heat-sensitive layer as an anode (if the conductive layer is a metal layer) or a cathode (if the conductive layer is a metal oxide) and applying electricity, only the heat-treated portion of the heat-sensitive layer, that is, the latent image area, becomes conductive. Therefore, only in that area,
The conductive layer (metal layer) 1 is oxidized and eluted to form a negative pattern image 7 (FIG. 5(A)), or the conductive layer l (
metal oxide layer) is reduced to form a positive pattern metal layer image 7' (FIG. 5(B)), which is then developed into a negative pattern 7 or a positive pattern 7' corresponding to the latent image. be.

In the above, the heat-treated portion of the heat-sensitive layer, that is, the latent image area 5, becomes more soluble in a solvent by heat treatment, so it may or may not be removed with a solvent at the same time as development, or after development. Furthermore, the entire heat-sensitive layer may be removed, and since the heat-sensitive layer in the present invention is generally transparent (of course, it may be opaque or colored), it may be necessary to remove it after development. , also serves as a protective layer for the formed image.

Note that any electrode material such as gold, platinum, or nickel can be used as a counter electrode to the above-mentioned recording material.

These counter electrodes may have any shape.

As the electrolytic solution, any conventionally known electrolytic solution such as water, acetonitrile, ethanol, dimethylformamide, dioxane, dichloroethane, and tetrahydrofuran can be used.
Br, KI, to LiC sentence, Li B F4, tetra-
n-butylammonium verchlorate, tetra-n-
Any electrolyte can be used, such as butylammonium perfluoroporate, tetramethylammonium chloride, Na, S04, etc.; It is preferable to dissolve it at a concentration of about O1 to IM.

Electrolytic conditions vary depending on the type and shape of the electrode, the type and concentration of the electrolytic solution and electrolyte, and the size of the recording surface of the recording material used in the present invention, but are generally 1 to 1.
A DC voltage of 1 ov is applied, and development is completed in several seconds to several minutes.

As explained in detail above, the image forming method of the present invention uses a heat-sensitive layer formed from a specific polymer complex on a conductive layer on a substrate, and the formed heat-sensitive layer is exposed to a normal atmosphere. It does not lose any of its heat sensitivity even if it is left under a normal atmosphere, and there is no need to take special precautions when forming the heat-sensitive layer in a normal atmosphere, making it industrially advantageous to manufacture. be.

In addition, the formed latent image is easily developed by an electrochemical method, and if the conductive layer is a metal layer and the substrate is transparent, it becomes a negative pattern in which only the image portion is transparent.
Further, if the substrate is colored, a colored image is formed.

Further, when the conductive layer is made of a metal oxide, one image portion becomes an opaque positive pattern with metallic luster, and an image with excellent resolution can be formed in both cases.

Also, if the heat-sensitive layer in one image area is not removed, the area where the latent image was and the other areas will return to the same state as the stable polymer complex before recording over time, and as a whole, under ambient conditions. Since the film does not change even partially, it functions as a protective layer for the image, and the storage stability of the recorded image is extremely excellent.

Next, the present invention will be explained in more detail by giving examples.
Note that "%" or "%" in the middle of the sentence is based on weight.

Example 1 Polyvinylpyrrolidone (K=90) 4 parts Methyl vinyl ether/maleic anhydride-monobutyl nistyl copolymer (Gantret ES-425, 50% ethanol solution, manufactured by GAF) 12 parts Ethanol 100 parts Dimethylformamide Loo parts The mixed solution F was mixed with aluminum vapor-deposited Mylar (aluminum thickness 2.oooX, Mylar thickness looILm, resistance 1QC, size 20X20C).
(2) was coated uniformly on the film using a Meyer's bar (#32) and dried at 100° C. for 5 minutes to obtain a recording material having a heat-sensitive layer with a thickness of 3 ILm.

Next, an argon laser (wavelength 514 nm, power 10 mW) was applied to IILSe from the surface of the heat-sensitive layer of the recording material.
Bit recording was performed by C irradiation.

Next, this was connected to the anode of a DC power supply, a nickel plate was connected to the cathode, and constant voltage electrolysis (3V, 5 seconds) was performed in a 0.1M saline electrolyte. The aluminum layer corresponding to the pattern was eluted and removed to form a negative pattern. The resolution of the image obtained was 100 wood/mm. Further, when all the heat-sensitive layers were removed after development, a conductive image pattern was obtained. Example 2 Using the polymer solution for the heat-sensitive layer used in Example 1, it was coated on an ITO glass substrate (resistance 200C, size 20 x 20 cm) in the same manner as in Example 1 to a thickness of 2I.
A recording material having a heat-sensitive layer of Lm was obtained. Example 1
After heat treatment in the same manner as in Example 1, this recording material was connected to the cathode of a DC power source, a nickel plate was connected to the anode, and the recording material was placed in an electrolyte of water containing 0.1M salt in the same manner as in Example 1. When constant voltage electrolysis (5 V, 10 seconds) was performed, the heat-treated ITO surface turned brown, and a brown positive pattern was formed on the colorless and transparent background.

[Brief explanation of the drawing]

1 and 2 schematically show the structure of the recording material used in the present invention, FIG. 3 schematically shows the thermal pattern treatment in the method of the present invention, and FIG. 4 shows the method of the present invention. FIG. 5 schematically shows the developing method in FIG. 5, and FIG. 5 schematically shows the developed recording material. ■...Conductive layer 2...Substrate 3...Thermosensitive layer 4...Thermal pattern 5...Latent image 6...
・Electrolyte 7.7'... Image 8...
...Cathode 1"...Recording material Figure 1 Figure 4

Claims (1)

[Claims] It consists of a substrate and a heat-sensitive layer provided on the substrate, the substrate consists of a metal layer or a conductive metal oxide layer provided on an insulating substrate, and the heat-sensitive layer is a polymer complex of a basic polymer and an acidic polymer. 1. An image forming method comprising thermally patterning a recording material to form a latent image, then immersing the recording material as one electrode in an electrolytic solution and applying electricity to develop the latent image portion.