JPH0522588B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an electrically conductive thermal transfer recording material;
It relates to a material for recording by transferring a heat-sensitive transfer layer using heat generated by applying electricity at a low voltage of 100V or less.

[Prior art]

In recent years, information has become extremely abundant, and the need for prompt transmission and recording of that information has increased, and various developments have been made regarding information management systems such as information processing systems, information transmission systems, and information recording systems. , an electric transfer recording system is also a typical example.

The present inventors have developed a material that can be transferred and recorded onto plain paper, etc. at low voltage without scattering carbon black or producing a bad odor, and has developed a material that is made of a metal-containing resin layer made of a resin matrix and metal powder, and a conductivity imparting agent and a resin matrix. Current-carrying recording material in which a semiconductive resin layer and a dynamic conductive layer are laminated (Japanese Patent Application Laid-Open No. 55-22917)
etc. are proposed.

However, since the above-mentioned recording material uses carbon black, graphite, etc. as a conductivity imparting agent, the recorded image becomes black or a color close to black, and even if a coloring agent is added, it is not possible to obtain a clear colored image.

In addition, there is a thermal transfer recording material consisting of two electrically resistive material layers (a low resistance layer on the surface and a high resistance layer on the inside) having an electrical resistance value of 1.1 to 1000, a conductive layer made of a good electrical conductor, and a heat transferable ink layer. Unexamined Japanese Patent Publication 1987-
93585) has been proposed. However, in the above-mentioned recording materials, the range in which both the low resistance layer and the high resistance layer can be transferred and recorded without being damaged by discharge is narrow, and it has been difficult to perform transfer recording without causing discharge damage.

[Problem that the invention seeks to solve]

The purpose of the present invention is to record images in clear colors on plain paper, etc. under a wide range of recording conditions, by performing current recording at a low voltage, without causing discharge damage, scattering of the conductivity imparting agent, or generating bad odors. An object of the present invention is to provide an electrically conductive heat-sensitive transfer recording material that can be transferred and recorded under the conditions.

[Means for solving problems]

The resin matrix used in the present invention only needs to have film-forming ability and electrical insulation properties, and thermoplastic resins are preferably used. The above-mentioned thermoplastic resin is desirably one that has a high binding strength to the conductivity imparting agent, has high mechanical strength when molded into a sheet or film, is flexible, and has strong stiffness, such as polyethylene, polypropylene, Polyvinyl chloride, polyvinyl acetate, ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, polystyrene, polycarbonate, polyacrylonitrile, polyvinyl acetal, polyacrylic ester, polymethacrylic ester, polyarylate, polysulfone, Examples include polyoxybenzylene, polyester, cellulose acetate, polyurethane, polyhinyl alcohol, carboxymethyl cellulose, gelatin, etc. Polyethylene, polyvinyl chloride, vinyl chloride-ethylene copolymer, vinyl chloride-vinyl acetate copolymer, polyvinyl Acetal, cellulose acetate and polyurethane are preferably used.

Also preferably used are thermosetting resins that react and harden after being molded into a sheet or film.
Examples of the thermosetting resin include phenol resin, urea resin, epoxy resin, urethane resin, and polyester resin.

The conductivity imparting agent used in the present invention preferably has good conductivity, such as copper, aluminum, iron, tin, zinc, nickel, molybdenum, silver,
Metal powders such as bronze and brass, carbon black, graphite, zeolite, zinc oxide, secondary oxide
Tin, metastannic acid, cuprous iodide, reduced titanium oxide,
Examples include ferric oxide.

Further, metal powder coated with other metals can also be used, such as copper powder coated with silver. Among the metal powders mentioned above, copper, zinc, and iron are more preferably used. In addition, the particle shape of the metal powder is preferably a resin-like one produced by electrolysis, and the particle size is preferably small and uniform, and the average particle size is preferably 0.2 to 20 microns, more preferably. It is 0.5 to 10 microns, and the particle size of the conductivity imparting agent other than the metal powder is preferably 10 microns or less.

The surface layer A, which is the first layer in the present invention, is composed of the above-mentioned resin matrix and a conductivity imparting agent, and is a layer that will not be destroyed by discharge during current recording, and one or more conductivity imparting agents may be selectively used. It is often said that if the amount added is too small, the conductivity will be low, and conversely, if the amount added is too large, the conductivity will be too good and the current applied from the recording needle will be spread out, causing it to drop directly below the recording needle. Since it becomes difficult to bend and the recording accuracy decreases, the metal-containing resin layer should be made to have a surface resistance of 4 to 70% by volume and a surface resistance of ^105.
10 ¹⁶ Ω, preferably 10 ⁷ to 10 ¹⁴ Ω. Although the thickness of the layer is not particularly limited, it is preferably 5 to 50 microns.

The surface layer A is made of an electrically conductive heat-sensitive transfer recording material, and during electrical recording, it is brought into contact with a recording needle and electrical recording is performed, thereby eliminating the risk of the surface layer causing cracks, etc., and improving storage stability. Plasticizers, fillers, lubricants, stabilizers,
Antioxidants, flame retardants, etc. may be added.

The method for forming the surface layer A is not limited in any way, and any known method such as solution casting, emulsion casting, calendaring, extrusion, etc. may be employed.

The second layer of the present invention, semiconductive B, is made of the resin matrix and the conductivity imparting agent, or is made of a thin film of a semiconductive substance, and has a surface resistance of more than 1Ω and less than 10 ⁵ Ω. It is a layer that generates heat without being destroyed by discharge during energization recording,
It is laminated on the surface layer A.

When the semiconductive layer B is composed of a resin matrix and a conductivity imparting agent, generally the resin matrix
50 to 500 parts by weight of carbon black and 1 to 1000 parts by weight of conductivity imparting agents other than carbon black are added to 100 parts by weight, and the thickness of the layer is 2 to 500 parts by weight.
Preferably it is 30 microns. Further, any method may be used to form this layer, for example, it may be formed in the same manner as the surface layer A.

Examples of the semiconductive substance include tin oxide,
Examples include indium oxide and chromium oxide, and the thickness of the thin film is preferably 100 to 2000 angstroms. Any method may be used to form the thin film, such as ion sputtering,
Examples include ion plating method and ion cluster beam method.

In the present invention, the third layer, the conductive layer C, is made of a metal thin film and is not destroyed by discharge during current recording.
It is a layer that generates heat, and is laminated on the semiconductive layer B. If its surface resistance is too small, the amount of heat generated will be small, and if it becomes too large, it will be destroyed when electricity is applied, so it is set to 0.1 to 1Ω. . Conductive layer C
As the thickness becomes thinner, the surface resistance becomes larger than 1Ω, and as it becomes thicker, the surface resistance becomes smaller than 0.1Ω, so the thickness is preferably 400 to 5000 angstroms, preferably 500 to 3000 angstroms, and more preferably 600 angstroms. ~2000 angstroms. Examples of the metal include aluminum, silver, gold, copper, zinc, tin, nickel, and molybdenum, with aluminum being preferably used.

Any method may be used to form the conductive layer C, such as a vacuum evaporation method, an ion plating method, an electroless plating method, and the like.
In addition, if there are minute defects or pinholes in the metal thin film, the current will concentrate in those areas when electricity is applied, making it easy to cause discharge damage. Therefore, in order to eliminate the defects and pinholes, the above method is used to form two or more layers. It is preferable to form the conductive layer C by laminating metal thin films.

Furthermore, if the difference in surface resistance between semiconductive layer B and conductive layer C is small, the amount of heat generated during energization recording will decrease, so the ratio of the surface resistance of semiconductive layer B to that of conductive layer C will decrease. is preferably 10 or more and less than 10 ⁶ .

The thermal transfer layer D, which is the fourth layer in the present invention, is
This layer is composed of a colorant and a binder, and is transferred by heat during current recording, and is laminated on the conductive layer.

Any known pigment or dye can be used as the coloring agent, such as nickel yellow, titanium yellow, cadmium red, naphthol yellow, permanent orange, crystal violet, malachite green, phthalocyanine blue, brilliant carmine 6B, etc. , the amount added may be arbitrarily determined depending on the color, density, etc. when recorded. In order to obtain a black recorded image, carbon black, unlin black, triiron tetroxide, etc. may be added.

The above-mentioned resin matrix may be used as the binder, but since the layer is thermally transferred, it is preferably one with a melting point of 50 to 110°C, such as paraffin wax, carnapower wax, polyethylene wax, etc. Examples include polystyrene, low molecular weight polystyrene and its derivatives, polyvinyl butyral, vinyl chloride-vinyl acetate copolymer, polyamide, polyurethane, ethylene-vinyl acetate copolymer, petroleum resin, and the like.

The thickness of the layer D is preferably 0.5 to 20 .mu.m, more preferably 1 to 10 .mu.m, since thermal transfer becomes difficult as the layer D becomes thicker.

Furthermore, if the thermal transfer layer D contains a large amount of colorant, the colorant may contaminate the recording paper when the recording material of the present invention is laminated with recording paper and electrical recording is performed. Preferably, the heat-sensitive transfer layer is formed of two or more layers, and the outermost layer contains a small amount of colorant.

The method for forming the heat-sensitive transfer layer D is not limited in any way, and examples include solution casting, emulsion casting, calendaring, extrusion, and gravure printing. When D is formed, a return electrode can be installed on the transfer D side during electrical recording, and a more uniform and stable recorded image can be obtained compared to the case where the return electrode is installed on the surface layer A. This is preferable because it allows

The structure of each layer of the recording material of the present invention is as described above, and the surface layer A, the semiconductive layer B, the conductive layer C, and the heat-sensitive transfer layer D are sequentially laminated to form an electrically conductive heat-sensitive transfer recording material.

〔Effect of the invention〕

The structure of the current-carrying heat-sensitive transfer recording material of the present invention is as described above. When a recording paper such as a plastic film is brought into contact with electricity and recorded, heat is generated between the semiconductive layer B and the conductive layer C directly below the recording needle, and this heat transfers the thermal transfer layer D to the recording paper and records the recording. Ru. At this time, the voltage of the electricity applied can be low, less than 100V, and the recording speed can be increased. Furthermore, the surface layer A, the semiconductive layer B, and the conductive layer C are not destroyed by electrical discharge and do not change in any way even when energized and recorded, and since energized recording is performed at a low voltage, there is no generation of media or odor during recording. do not have.
Also, similar to conventional discharge recording, recording can be performed at a higher speed than thermal transfer recording, and highly reliable and clear recording with an image density comparable to that of thermal transfer recording can be obtained.

Also, the surface resistance is the highest in the surface layer A, and decreases in order from the semiconductive layer B and the conductive layer C, and the ratio of the surface resistance of the semiconductive layer B and the conductive layer C is relatively small. Each layer is not destroyed by discharge and has semiconducting B
Also, the recording conditions for generating heat in the conductive layer C are wide, and it is easy to use.

Therefore, the recording material of the present invention is suitably used for printing out records and displays in facsimiles, various measuring instruments, recorders, and computers.

Furthermore, the recording material of the present invention does not cause any turbidity in not only black recording but also color recording, so it is extremely effective for high-speed printout of color recording displays.

〔Example〕

Next, examples of the present invention will be described. Hereinafter, the term "parts" simply means "parts by weight."

Example 1 Vinyl chloride-vinyl acetate copolymer (degree of polymerization 650,
Vinyl acetate 13%) 100 parts Electrolytic copper powder (average particle size 1.5μ) 200 parts Ethyl acetate 200 parts Toluene 200 parts The above composition was dissolved and dispersed, cast onto a glass plate, dried, and thickened. A surface sheet with a diameter of 7μ was obtained. The electrolytic copper powder was 21.0% by volume in the sheet. The surface resistance of the sheet was 0.6×10 ⁸ Ω.

Butyral resin (polymerization degree 1700, acetalization degree 66)
%) 100 parts thermal black 160 parts acetylene black 60 parts ethyl alcohol 1400 parts Next, the formulation consisting of the above composition was dissolved and dispersed, coated on the above surface sheet and dried to form a semiconductive layer with a thickness of 12 μm, and a semiconductive layer with a thickness of 19 μm. A laminated sheet with a thickness of . The surface resistance of the semiconductive layer was 0.8×10 ⁴ Ω.

3× on the semiconductive layer surface of the obtained sheet
Aluminum was vacuum-deposited twice under 10 ^-5 Torr conditions to form a conductive layer with a thickness of 900 Å and a surface resistance of 0.2 Ω to obtain a composite sheet.

Ketone resin (manufactured by Honshu Kagaku Co., Ltd., trade name Halon 80)
100 parts Alloy dye (manufactured by Hodogaya Chemical Co., Ltd., trade name: Spiron Black BNH) 25 parts Beeswax 15 parts Carnapowerx 15 parts Ethyl acetate 50 parts Toluene 25 parts Next, the mixture having the above composition was dissolved and dispersed to form the composite sheet. It was applied onto the conductive layer using a gravure coater and dried to form a heat-sensitive transfer layer with a thickness of 4μ to obtain an electrically conductive heat-sensitive transfer recording material with a thickness of 23μ.

The obtained recording material is fed to a mimeograph paper making machine (manufactured by Gestetner, an improved version of the product name Guestfax 1100), a piece of high-quality paper is brought into contact with the bottom of the heat-sensitive transfer layer, and a recording needle is brought into contact with the surface sheet. contact, direct current
When 60V electricity was applied and recording was performed at a scanning line density of 12/mm and a recording speed of 1.2m/sec, there was no scattering of media or aluminum powder, and there was no bad odor on the top sheet, semiconductive layer, or conductive layer. A clear black image was obtained on the high-quality paper without any through-holes. The image density obtained was 1.25.

Example 2 Polyvinyl acetal (degree of polymerization 1750, degree of acetalization 67%) 100 parts Conductive zinc oxide powder (average particle size 1 μ) 300 parts Ethyl alcohol 1000 parts A blend having the above composition was dissolved and dispersed, and placed on a glass plate. It was cast and dried to obtain a top sheet with a thickness of 5 μm. Zinc oxide powder was 37% by volume in the sheet. Moreover, the surface resistance was 2.2×10 ⁶ Ω.

Polyvinyl acetal (degree of polymerization 1750, degree of acetalization 67%) 100 parts Thermal black 160 parts Acetylene black 60 parts Ethyl alcohol 1400 parts The blend consisting of the above composition was dissolved and dispersed, coated on the above top sheet and dried to a thickness of 15 μm. A semiconductive layer was formed to obtain a laminated sheet with a thickness of 20 μm. The surface resistance of the semiconductive layer was 0.3×10 ⁴ Ω.

3× on the semiconductive layer surface of the obtained laminated sheet
Aluminum was vacuum-deposited twice under conditions of 10 ^-5 Torr to form a conductive layer with a thickness of 900 Å and a surface resistance of 0.2 Ω to obtain a composite sheet.

Ketone resin (manufactured by Honshu Kagaku Co., Ltd., trade name Halon 80)
100 parts Brilliant Carmine 6B 20 parts Beeswax 15 parts Carnauba wax 15 parts Ethyl acetate 50 parts Toluene 25 parts Next, the formulation consisting of the above composition was dissolved and dispersed, coated on the conductive layer of the composite sheet with a gravure coater and dried. Form a heat-sensitive transfer layer with a thickness of 4μ,
An electrically conductive heat-sensitive transfer recording material having a thickness of 24 μm was obtained.

When the obtained recording material was used for electrical recording in the same manner as in Example 1, there was no scattering of the medium or generation of bad odor, and a clear red image was obtained on the high-quality paper. The image density obtained was 1.15.

Example 3 A semiconductive layer made of a thin film of chromium oxide was formed on the top sheet obtained in Example 1 by a cluster ion beam method to obtain a laminated sheet. The thickness of the semiconductive layer was 1000 Å, and the surface resistance was 0.6×10 ³ Ω.

Next, a conductive layer and a heat-sensitive transfer layer were formed in the same manner as in Example 1 to obtain an electrically conductive heat-sensitive transfer recording material having a thickness of 23 μm.

When the obtained recording material was used for electrical recording in the same manner as in Example 1, there was no scattering of the medium or generation of bad odor, and a clear black image was obtained on high-quality paper. The image density obtained was 1.10.

Example 4 A semiconductive layer was formed on the topsheet obtained in Example 2 in the same manner as in Example 3, and then a conductive layer and a heat-sensitive transfer layer were formed in the same manner as in Example 2. An electrically conductive heat-sensitive transfer recording material having a thickness of 24 μm was obtained. The thickness of the semiconductive layer is 1000Å, and the surface resistance is
It was 0.6×10 ³ Ω.

When the obtained recording material was used for electrical recording in the same manner as in Example 1, there was no scattering of the medium or generation of bad odor, and a clear red image was obtained on the high-quality paper. The image density obtained was 1.05.

Comparative Example 1 Except that aluminum was vacuum-deposited on the semiconductive layer surface of the laminated sheet obtained in Example 1 under conditions of 3 × 10 ^-6 Torr to form a conductive layer with a thickness of 400 Å and a surface resistance of 2 Ω. A recording material was obtained in the same manner as in Example 1.

When the obtained recording material was subjected to electrical recording in the same manner as in Example 1, the conductive layer was destroyed by discharge and was transferred together with the heat-sensitive transfer layer.

There was a slight odor during recording, and the density of the image obtained was 0.85.

Comparative Example 2 Instead of conductive layer, thickness ¹⁰⁵ Å, surface resistance
A composite sheet was obtained in the same manner as in Example 1 using aluminum foil with a resistance smaller than 0.1Ω (unmeasurable with a tester), and thermal transfer was performed on the aluminum foil of the sheet in the same manner as in Example 1. A recording material was obtained by forming a layer.

Using the obtained recording material, electrical recording was carried out in the same manner as in Example 1, but a clear recorded image could not be obtained.

Claims (1)

[Scope of Claims] 1. A laminate having a four-layer structure, wherein (A) the first layer is composed of a resin matrix and a conductivity imparting agent, and the conductivity imparting agent accounts for 4 to 70% by volume;
and a surface layer with a surface resistance of 10 ⁵ to 10 ¹⁶ Ω that is not destroyed by discharge during current recording; (B) the second layer is made of a resin matrix and a conductivity imparting agent or is made of a thin film of a semiconductive substance; A semiconductive layer with a surface resistance of more than 1Ω and less than 10 ⁵ Ω, which is not destroyed by discharge and generates heat during current recording; (C) The third layer is made of a metal thin film and has a surface resistance of 0.1.
~1Ω, not destroyed by discharge during current recording,
An electrically conductive heat-sensitive transfer recording material characterized in that the heat-generating conductive layer and (D) the fourth layer are composed of a heat-sensitive transfer layer made of a colorant and a binder, and are laminated in the above order.