JPS61169870A - 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-period stable preservation of an image by using a recording material formed with a specifically constituted recording layer and thermosensitive layer on a conductive substrate. CONSTITUTION:The recording material 10 is formed by forming the recording layer 2 consisting of a colored electrolytically polymerized film on the insulating substrate 1 consisting of a metallic plate of gold, platinum, copper, etc. and depositing further the thermosensitive layer 3 consisting of a polymer complex composed of a basic polymer such as N-vinyl pyrolidone an acidic polymer such as citric acid thereon to form the material 10. Such material 10 is exposed to a heat pattern to form a latent image in the layer 3. The material in such a state is immersed in 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-period 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 types of information using a thermal pattern to form a visible image. A recording layer and a heat-sensitive layer having a specific configuration are formed, a latent image is formed in the heat-sensitive layer by a thermal pattern, and the recording layer is developed by electrochemical means using the latent image to easily form a visible image. An object of the present invention is to provide an image forming method that can perform the following steps.

(Prior Art) Many methods have been known for recording various types of information using thermal patterns. By providing variable heat sensitive layers and applying a thermal pattern to these heat sensitive layers, a visible change in the heat sensitive layer or a recorded image readable by other readout means is formed. 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) Heat-sensitive polymers and dyes are often used to form the heat-sensitive layer of recording materials used in the conventional recording method using thermal patterns as described above. When forming a heat-sensitive layer from materials, there is a problem in that sufficient care must be taken in handling the materials.

That is, in order to form heat-sensitive layers from materials that are sensitive to thermal patterns, those materials must be heat-invariant before use, and for similar reasons, storage of recording materials after formation requires further If sufficient care is not taken, there is a problem that the material will lose its heat sensitivity before use and become 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 there is still a strong demand for it.

As a result of intensive research in response to the above-mentioned demands of the prior art, the present inventors have discovered that a conductive substrate is used as a support base for a recording material, a recording layer is formed from a specific material, and a heat-sensitive layer is constructed. When a polymeric material with a specific composition is used as a material for recording, various types of information can be easily recorded by thermal patterns, and the latent image of the recorded information can be used to create a visible image by specific electrochemical means. The present invention was completed based on the finding that recorded images with excellent storage stability can be obtained by this method.

(Means for solving the problems) That is, the present invention comprises a conductive substrate, a recording layer provided on the conductive substrate, and a heat-sensitive layer provided on the recording layer,
A recording material in which the recording layer is made of a colored electropolymerized film and the heat-sensitive layer is made of a polymer complex of a basic polymer and an acidic polymer is treated with a thermal pattern to form a latent image, and then the recording material is electrolyzed. This is an image forming method that involves immersing the film in a liquid and developing it by applying one current.

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 is used as the substrate for the recording material used, the second feature is that the recording layer is formed of a specific colored polymer, and the third feature is that The fourth feature is that a specific polymer complex is used to form the heat-sensitive layer, and the fourth feature is that the recording material thus formed is treated with a thermal pattern in a conventional manner to prevent the formation of a latent image. The point is that electrochemical means are used for development.

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

The electrically conductive substrate used as the substrate of the recording material in the present invention may be any material as long as it is electrically conductive, such as metal plates such as gold, platinum, silver, nickel, copper, these metals, tin oxide, A conductive oxide such as indium oxide, indium-tin oxide, or other conductive material may be deposited on one or both sides of any arbitrary substrate 1, such as a glass plate, various resin films, or sheets.

In the present invention, the recording layer provided on the substrate is formed by electrolytic polymerization. Such electrolytic polymerization is a method in which an electrolytically polymerizable top is added to an electrolytic solution and electrolytic polymerization is performed using a conductive substrate as an anode.

The electrolytic polymerization method preferably used in the present invention includes, for example, “Oyoi Jisho, Vol. 52, No. 11 (1983) P.
971-974, but according to detailed research by the present inventor, such an electropolymerized membrane absorbs heat very well, and the film formed on the membrane It has been found that the heat-sensitive layer has improved heat sensitivity, facilitates thermal changes in the heat-sensitive layer, and can be easily electrochemically developed later, and is suitable as the recording layer of the recording material in the present invention. be.

That is, when electricity is applied in an electrolytic solution containing 1,000 yen for electrolytic polymerization using the above-mentioned conductive substrate as an anode, electrolytic polymerization occurs on the surface of the anode, and a colored electrolytic polymer film is formed on the surface. A recording layer with excellent performance is formed.

Examples of monomers used in such electrolytic polymerization include monomers such as virol, thiophene, furan, selenophene, tellurophene, indole, azulene, aniline, chenothiophene, hyrolopyrrole, and diacetylene. Approximately 0.
It is preferable to use it at a concentration of about 001-LM.

In addition, as the cathode which is the opposite electrode to the above anode, gold, platinum,
Any electrode material such as nickel may be used, and these cathodes may have any shape.

As the electrolyte, any conventionally known electrolyte such as water, acetonitrile, ethanol, dimethylformamide, dioxane, dichloroethane, and tetrahydrofuran can be used.
r, K1. LiCfL04, LiB%, Tetra-n
Any electrolyte can be used, such as -butylammonium verchlorate, tetra-n-butylammonium perfluoroporate, tetramethylammonium chloride, N axs O+, etc., and these electrolytes are soluble in concentrations of about 0.01 to IM. is preferred.

The electrolytic polymerization conditions vary depending on the type of hexamer used, 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 conductive substrate used in the present invention. Generally, by applying a DC voltage of 1 to 1 Ov, approximately 0.1 to 1 Ov is applied on the conductive substrate in several seconds to several minutes.
A colored electropolymerized film, ie, a recording layer, having a thickness of ILm is formed.

The electropolymerized membrane formed as described above is generally strongly colored from brown to black depending on the type of electrolyte, but if the degree of coloring is small, anionic dyes such as acid dyes and direct dyes may be added to the electrolyte. By dissolving an appropriate amount of a pigment such as a dye having a group.

You can change the hue of the coloring or increase the density.

Further, it is natural that the dyeing process may be carried out after the dyeing process is completed and the film is formed.

The polymer complex used to form the heat-sensitive layer on the recording layer on the substrate is composed of a basic polymer and an acidic polymer.
The basic polymer itself is already known in Japanese Patent No. 5-42744, and includes, for example, the following.

N-vinylpiperidone, 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-vinylcapryllactam, N-vinyl-3-
Morpholine, N-vinylthiopyrrolidone, N-vinyl-
Homopolymers such as 2-pyridone or random copolymers, pro-copolymers, graft copolymers, etc. with other common monomers; N-vinyl-2-oxacylidone, N-vinyl-5-methyl -2-oxazolidone, N-vinyl-5-ethyl-
2-oxacylidone, N-vinyl-4-methyl-2-oxazolidone, N-vinyl-2-thioxazolidone,
Homopolymers such as N-vinyl-2-mercaptobenzothiazole or random copolymers with other common monomers, block copolymers, graft copolymers, etc.; N-vinylimidazole, N-vinyl-2- Homopolymers such as methylimidazole and N-vinyl-4-methylimidazole, or random copolymers with other common monomers, block copolymers, graft copolymers, etc.; 2- or 4-vinylpyridine, etc. Examples include homopolymers and random copolymers, block copolymers, and graft copolymers with other common monomers. Other copolymerizable monomers that may be used in the above include methacrylates, acrylates, Acrylamide, acrylonitrile, vinyl ether, vinyl acetate, vinyl imidazole,
Ethylene, styrene and other common heptamers, among others, are particularly useful in the present invention: N-vinylpyrrolidone, N-vinylpiperidone, N-vinylcaprolactam, N-vinylmorpholine, N-vinyl-2-oxazolidone. , a homopolymer, a copolymer of N-vinyl-5-methyl-2-oxacylidone, and the like. 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.

Further, examples of acidic polymers that can form a polymer complex with the above basic polymer 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 such as vinyl ether ester monomers of polyhydric carboxylic acids, random copolymers with other common heptamers, block copolymers, graft copolymers, etc. Tokuko Sho 35-8495
(Refer to the publication No. 2006)) A heptamer homopolymer such as nialic acid or methacrylic acid or a random copolymer with other common monomers,
Block copolymers, graft copolymers, etc.: Random copolymers, block copolymers, homopolymers of α,β-unsaturated vinyl humers such as maleic anhydride, itaconic acid, or other common monomers; Graft copolymers, etc.: Random copolymers, block copolymers, graft copolymers, etc. with other sulfonic acid or phenol group-containing homopolymers or other common monomers; Other carboxyl groups or acidic modified products of various polymers with compounds containing sulfonic acid groups or phenol groups: Although any of the above acidic polymers can be used, particularly preferred in the present invention are α,β-unsaturated acids alone. These include polymers, random copolymers, block copolymers, and graft copolymers, and particularly preferred is a copolymer of alkyl vinyl ether and maleic anhydride.

Users have 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, the two polymers interact with each other in some way. If a polymer complex different from either polymer is formed and both polymers are mixed in a relatively good solvent, the polymer complex will precipitate, and if mixed in a relatively good solvent, a significant increase in viscosity etc. will occur, and the use of It has been discovered that this polymer has properties different from that of a mere mixture of both polymers.

Therefore, the polymer complex used in the present invention means a polymer complex consisting of the above-mentioned polymers. In the present invention, it is preferable to use both polymers in such a manner that their basicity and acidity are approximately the same. The mixing ratio can be determined by calculating the basicity and acidity of both polymers and determining the mixing ratio of both polymers accordingly. Furthermore, a polymer complex formed by mixing in an appropriate ratio becomes a polymer complex that cannot be strongly dyed by either acidic dyes or basic dyes. Therefore, the mixing ratio of both polymers can be determined using these factors.

Since the polymer complex obtained as described above is generally not soluble in relatively poor solvents such as water, alcohol, ester, hydrocarbon, etc., both polymers are dissolved in these poor solvents, respectively. By mixing the internal solutions one can isolate the polymer complex used in the present invention. 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 a conductive substrate as described above using a polymer complex as described above, (1) Prepare solutions of both polymers,
A method in which one of the solutions is applied to the surface of the recording layer on the substrate, and then a predetermined amount of the other polymer solution is applied thereon to form a polymer complex on the recording layer.

(2) A method can be used in which a solution of the polymer complex is prepared using a relatively good solvent as described above and the solution is applied onto the recording layer.

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 mentioned 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 schematically shows the structure of the recording material 1O of the present invention with its cross-sectional shape, where 1 represents a conductive substrate as described above, 2 represents a recording layer made of an electrolytic polymer film, 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, 1 the recording material used in the present invention is
In this method, a recording layer 2 made of an electrolytically polymerized film is formed on at least one surface of a conductive substrate 1, and a thermosensitive layer 3 made of the above-mentioned polymer complex is further formed thereon. As shown in Figure 2, a recording layer 2 is formed on both sides of the conductive □substrate 1.
If the heat-sensitive layer 3 is formed, the recording material 10 will have the recording layer 2 and the heat-sensitive layer 3 on both sides. When forming the recording layer 2 and the heat-sensitive M3 only on one surface, it is preferable to apply an insulating coating (not shown) of an arbitrary thickness to the other surface.
However, this is not necessary when the conductive substrate 1 itself is a single-sided conductive substrate such as ITO vapor-deposited glass or aluminum vapor-deposited film.

The conductive substrate l used can technically have any thickness and any shape, but generally has a thickness of about 0.0
A plate, sheet, or film with a thickness of 3 to 3 mm is preferable, and the shape may be any shape, such as a tape, depending on the intended use of the resulting recording material. It may have the same shape or a smaller area, and the thickness is generally preferably about 0.1 to 10 JLm. The heat-sensitive layer 3 may be formed by the one-liquid method as described above or by the Z-liquid method, but it is generally preferable to have a thickness of about 0.1 to 10 gm.

The inventor has discovered that the recording material formed as described above becomes a poor conductor as a whole and loses its good conductivity, even though the substrate 1 and recording layer 2 thereof are conductive. . This could naturally be predicted since the two types of polymers constituting the polymer complex forming the heat-sensitive layer 3 are mutually neutralized, but further detailed research by the present inventors revealed that this could be expected. found that when these heat-sensitive layers are exposed to a thermal pattern with greater energy than the surrounding atmosphere, only that portion of the heat-sensitive layer becomes conductive again, that is, a latent image consisting of conductive regions is formed. This is what I did. Furthermore, such a latent image is
Even after the application of the thermal pattern was discontinued, it maintained its electrical conductivity for several minutes to several days, and then returned to its 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 shown schematically in FIG. , a thermal stylus, a thermal type, a mechanical method that locally and selectively heats the heat-sensitive layer of a recording material using a thermal printing head or beam scanning such as a laser beam or an electron beam, or a radiation-absorbing character pattern. Any other method may be used, such as a radiant heating method in which the original and the recording material are placed one on top of the other in a heat-conducting position and irradiated with intense radiation using an incandescent tungsten lamp or the like.

As described above, a desired latent image 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 in the following manner. The development method is also an important feature of the 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 used in the present invention, and FIG. 5 schematically shows a cross section of the developed recording material IO. This is what is shown.

As shown in FIGS. 4 and 5, one preferred method for developing is to soak the recording material 1O on which these latent images have been formed in an electrolytic solution 6.
By immersing it as an anode and applying electricity, only the latent image area becomes conductive, and as a result, the electrolytic polymer film, which is the recording layer corresponding to the latent image area, becomes colorless due to electrochemical action.

Although the mechanism of this colorlessness is not clear, it is thought that the conjugated system in the electrolytically polymerized film, which is the recording layer, is oxidized and cleaved by anodic oxidation during energization, resulting in colorlessness. Furthermore, when one dye anion is present in the polymer film, it is thought that the dye is similarly oxidized and decomposed to become colorless.

In this way, a negative pattern with high contrast is formed. Note that a thermal pattern is imparted to the non-image area.

Naturally, if the recording material is developed in the same way, a positive pattern will be formed. Furthermore, another method for obtaining a positive image is to go through the steps of applying a thermal pattern in the form of an image, developing it using the recording material as a cathode, and then immediately converting the recording material to an anode and developing it. Another major feature of the present invention is that the non-image area becomes colorless and a positive image is obtained.

In addition, the electrolytic solution 6 and cathode 8 in the above development process are as follows:
The electrolytic solution and cathode may be the same as those in the electrolytic polymerization described above, and the developing conditions may also be the same.

As explained in detail above, the image forming method of the present invention involves forming a recording layer made of an electrolytic polymer film on a conductive substrate, and further forming a recording layer made of a specific heat-sensitive polymer complex on the recording layer.
The recording layer and the heat-sensitive layer that have been formed do not lose their heat sensitivity at all even if they are left in a normal atmosphere, and the recording layer and the heat-sensitive layer In forming the layer, there is no need to pay special attention under normal atmosphere, so the production is industrially advantageous, and the formed latent image can be easily processed by electrolytic treatment. Developed into a high-contrast image. In addition, over time, the heat-sensitive layer after development returns to the same state as the stable polymer complex before recording, with the area where the latent image was and other areas returning to the same state as the stable polymer complex before recording. The storage stability of the recorded information is extremely excellent because it does not change or change even partially.

Next, the present invention will be explained in more detail with reference to Examples.

Note that "%" or "%" in the middle of the sentence is based on weight.

Example 1 0.1 M of pyrrole and 0.1 Mjl of sodium p-toluenesulfonate were dissolved in water to prepare an electrolytic polymerization solution. ITO with a resistance of 200 and a size lOloXlo is used as an anode for this.
A glass plate was inserted, a nickel plate was used as a cathode, and electrolysis was carried out at a DC voltage of 3 V for 50 seconds to form a greenish-brown conductive polypyrrole film (thickness: about IJLm) on the anode.

Next, the following polymer solution was applied to a dry film thickness of 3 ILm by a spinner coating method and dried to form a heat-sensitive layer, thereby obtaining a recording material used in the present invention.

Polyvinylpyrrolidone (K=90) 5 parts Polymethyl vinyl ether/maleic anhydride-monobutyl nystyl copolymer (Gantrett ES-425, 50% ethanol solution, manufactured by GAF) 10 parts Ethanol 100 parts Dimethylformamide 100 parts Argon laser (wavelength: 514 nm, power: 10 mW) was irradiated for 1 psec from the surface of the heat-sensitive layer of the recording material to perform bit recording.

Next, the above recording material was connected to the anode and the nickel plate was connected to the cathode, and when a DC voltage of 3 V was applied for 3 seconds in a 1% aqueous solution of sodium P-toluenesulfonate, only the areas irradiated with laser light were selectively exposed. The color changes from brown to colorless and transparent,
A negative pattern was formed. This image can be read out as a signal with a large transmitted light intensity ratio.

Example 2 A recording material prepared in exactly the same manner as in Example 1 was exposed to non-image areas with argon laser light in the same manner as in Example 1. When the recording material was connected to the anode and the nickel plate to the cathode and a DC voltage of 4 V was applied for 10 seconds, the exposed areas were brown and the non-exposed areas were colorless, forming a positive pattern. The obtained images had sufficient contrast and were useful for slides, masks, optical discs, etc.

Example 3 A recording material prepared in exactly the same manner as in Example 1 was imagewise exposed to argon laser light in the same manner as in Example 1, and then
When the above recording material was connected to the anode and the nickel plate was connected to the cathode in a 0.1M aqueous solution of sodium p-toluenesulfonate and a DC voltage of 4 V was applied for 10 seconds, the non-exposed areas were brown and the exposed areas were colorless and white. A positive pattern was formed. The images obtained have sufficient contrast.

It was useful for slides, masks, optical discs, etc.

[Brief explanation of drawings]

1 and 2 schematically show the structure of the recording material used in the present invention, FIG. 3 schematically shows the thermal pattern in the method of the invention, and FIG. 4 shows the structure of the recording material used in the method of the invention. The developing method is shown diagrammatically, and FIG. 5 diagrammatically shows the developed recording material. 1... Conductive base material 2... Recording layer 3... Heat sensitive layer 4... Laser 5... Latent image 6...・・・
・Electrolyte 7... Image 8...
...Cathode 10...Recording material patent applicant Canon Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] It consists of a conductive substrate, a recording layer provided on the conductive substrate, and a heat sensitive layer provided on the recording layer, the recording layer being made of a colored electropolymerized film, and the heat sensitive layer being made of a basic polymer and an acidic polymer. An image forming method comprising processing a recording material made of a polymer complex with a thermal pattern to form a latent image, and then immersing the recording material in an electrolytic solution and developing it by applying electricity.