JPH0356675B2 - - 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.

[Conventional technology]

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 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.

[Problem that the invention seeks to solve]

It is an object of the present invention to make it possible to transfer and record clear colored images onto plain paper, etc., without scattering carbon black or generating bad odors, by conducting current recording at a low voltage. An object of the present invention is to provide an electrically conductive heat-sensitive transfer recording material that does not cause background smudge due to its pressure sensitivity.

[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 power to metal powder, has high mechanical strength when molded into a sheet or film, is flexible, and has strong stiffness, such as polyethylene, polypropylene, polychloride, etc. Vinyl, polyvinyl acetate, ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, polystyrene, polyacrylonitrile, polyvinyl acetal, polyacrylic ester, polymethacrylic ester, polyester, cellulose acetate, polyurethane, polyvinyl alcohol , carboxymethylcellulose, gelatin, etc., and polyethylene, polyvinyl chloride, vinyl chloride-ethylene copolymer, vinyl chloride-vinyl acetate copolymer, polyvinyl acetal, cellulose acetate, and polyurethane are preferably used.

The metal powder used in the present invention means a metal in powder form, and the powder must have electrical conductivity. It is preferable to use a powder of a highly conductive metal, and specific examples of suitable metal powders include powders of copper, aluminum, iron, tin, zinc, nickel, molybdenum, silver, bronze, brass, and the like.

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. is 0.5-10 microns.

Metal-containing resin layer (A) which is the first layer in the present invention
is a layer made of the above-mentioned resin matrix and metal powder that is not destroyed by discharge during energization recording; one or more types of metal powder may be selected from among the above-mentioned metal powders as necessary; 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 spread and flow directly below the recording needle. The metal-containing resin layer 5.
~30% by volume and surface resistance of 10 ⁵ ~ 10 ¹⁶
and preferably
It is 10 ⁷ to 10 ¹⁴ Ω. Although the thickness of the layer is not particularly limited, it is preferably 5 to 50 microns.

The above-mentioned metal-containing resin layer (A) is used as an electrically conductive thermal transfer recording material, and during electrical recording, it is brought into contact with a recording needle and electrical recording is performed, so there is a risk that the metal-containing resin layer (A) may cause cracks, etc. , improve storage stability, and prevent constituent substances from adhering to the recording needle.
Furthermore, in order to improve the moldability of the layer, plasticizers, fillers, lubricants, stabilizers, antioxidants, flame retardants, etc. may be added.

Further, the method for forming the metal-containing resin layer (A) is not limited in any way, and any known method such as solution casting, emulsion casting, calendering, extrusion, etc. may be employed.

In the present invention, the second conductive layer (B) is a layer that is not destroyed by discharge during current recording, and is laminated on the metal-containing resin layer, and if its surface resistance is too small, the amount of heat generated will be small; If it becomes too large, it will be destroyed when electricity is applied, so it is set to 0.1 to 1Ω. Furthermore, if the difference in surface resistance between the metal-containing resin layer (A) and the conductive layer (B) is small, the amount of heat generated will decrease when electricity is recorded. The surface resistance ratio of (B) is preferably 10 ⁴ to 10 ¹⁶ .

The conductive layer (A) is formed of a thin metal film, and as the thickness becomes thinner, the surface resistance becomes greater than 1Ω, and as it becomes thicker, the surface resistance becomes less than 0.01Ω, so it is made to have a thickness of 400 to 5000 angstroms. is preferably 500 to 3000 angstroms, more preferably 600 to 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 (B), such as a vacuum evaporation method, an ion 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 (B) by laminating metal thin films. The third layer in the present invention, the thermal transfer layer (C), is made of a colorant and a binder, and is a layer that is transferred by heat during current recording, and is laminated on the conductive layer (B). be done.

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, unriblack, 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, carnauba wax, Examples include polyethylene wax, low molecular weight polystyrene and its derivatives, polyvinyl butyral, vinyl chloride-vinyl acetate copolymer, polyamide, polyurethane, ethylene-vinyl acetate copolymer, ketone resin, petroleum resin, and the like.

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

The fourth layer in the present invention, the thermal transfer layer (D), is
It is a layer that is composed of a colorant and a binder with a lower content than the heat-sensitive transfer layer (C) or only a binder, and is transferred by heat during electrical recording, and the heat-sensitive transfer layer Laminated on (C).

The colorant and binder may be the same as those used in the heat-sensitive transfer layer (C), or may be different, and may be selected from the materials listed above.
However, except for dark pigment dyes such as black, it is preferable to use dyes of the same color. In order to prevent pressure sensitivity due to recording stylus pressure, the amount of colorant added to the heat-sensitive transfer layer (D) must be smaller than the amount of colorant added to the heat-sensitive transfer layer (C). In other words, when the amount of the heat-sensitive transfer layer (C) is 100 parts by weight, the range of the amount of the heat-sensitive transfer layer (D) added is 0.
~50 parts by weight is preferred.

The thickness of the layer (D) is desirably as thin as possible as long as it has the ability to prevent pressure sensitivity, and is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm, since the transferred image density will decrease if it becomes thicker.

The method of forming the heat-sensitive transfer layers (C) and (D) is not limited in any way, and examples thereof include solution casting, emulsion casting, calendaring, extrusion, gravure printing, etc. Gravure printing When a heat-sensitive transfer layer is formed in a net shape, a return electrode can be installed on the transfer layer side during current recording, which is more uniform and stable than when the return electrode is installed on a metal-containing resin layer. This is preferable because it is possible to obtain a recorded image with a high quality.

The structure of each layer of the recording material of the present invention is as described above, including a metal-containing resin layer (A), a conductive layer (B), a thermal transfer layer with a high colorant concentration (C), and a thermal transfer layer with a low colorant concentration. The layers (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 paper or plastic film is placed under (D) and electricity is applied to record, heat is generated between the metal-containing resin layer (A) and the conductive layer (B) directly under the recording needle, and this heat causes the sensor to become sensitive. The thermal transfer layers (C) and (D) are transferred to recording paper and recorded. At this time, the voltage of the electricity applied can be low, less than 100V, and the recording speed can be increased. In addition, the metal-containing resin layer (A) and the conductive layer (B) 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, no soot or odor is generated during recording. . 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.

Furthermore, the recording material of the present invention does not produce through-holes even when it is energized and undergoes no change other than thermal transfer, so it can be used multiple times like carbon paper.

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.

Further, the recording material of the present invention can provide clear recorded images without any background smear caused by pressure sensitivity due to the stylus pressure of the discharge recorder.

〔Example〕

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

Example 1 Polyurethane resin (manufactured by Nippon Polyurethane Co., Ltd., trade name N-5109, 30% urethane, 70% dimethylformamide) 100 parts Electrolytic copper powder (average particle size 2.0μ) 70 parts Methyl ethyl ketone 110 parts Dissolve the above composition. It was decomposed, cast on a glass plate, and dried to obtain a metal-containing resin sheet with a thickness of 10 μm.

The electrolytic copper powder was 23.8% by volume in the sheet.

The surface resistance of the sheet was 0.6×10 ⁸ Ω.

Aluminum was vacuum-deposited twice on one side of the obtained sheet under conditions of 3×10 ^-5 Torr to a thickness of 800 Å.
A conductive layer with a surface resistance of 0.6Ω was formed to obtain a composite sheet.

Ketone resin (manufactured by Honshu Kagaku Co., Ltd., trade name Halon 80)
100 parts metal-containing dye (manufactured by Hodogaya Chemical Co., Ltd., trade name Spiron Black BNH) 25 parts ethyl acetate 50 parts toluene 25 parts beeswax 12 parts carnauba wax 25 parts Next, the mixture having the above composition was dissolved and dispersed, and the above composition was dissolved and dispersed. A heat-sensitive transfer layer with a thickness of 2 μm was provided on the conductive layer of the composite sheet by coating with a gravure coater.

Ketone resin (manufactured by Honshu Kagaku Co., Ltd., trade name Halon 80)
100 parts metal-containing dye (manufactured by Hodogaya Chemical Co., Ltd., trade name Spiron Black BNH) 3 parts ethyl acetate 50 parts toluene 25 parts beeswax 12 parts carnauba wax 25 parts Furthermore, the above composition was dissolved and dispersed, and the above composition was dissolved and dispersed. This was applied onto the thermal transfer layer using a gravure coater to form a 1 μm thick thermal transfer layer to obtain a 13 μm thick electrically conductive thermal transfer recording material.

The obtained recording material was fed to an improved mimeograph machine (Gusfax 1100, manufactured by Gestettner), and high-quality paper was brought into contact with the bottom of the heat-sensitive transfer layer, and a recording needle was brought into contact with the metal-containing resin sheet with a stylus pressure of 10 g. , direct current
When 35V electricity was applied, scanning line density was 12g/mm, and recording speed was 1.2m/sec, there was no scattering of soot or aluminum powder, almost no odor, and there were no through holes in the metal-containing resin sheet. A clear black image was obtained on high-quality paper without any occurrence of color. At that time, no soiling of the high-quality paper was observed, and the image density was 1.20.

Comparative Example 1 The thickness of the third thermal transfer layer in Example 1 was
When a 13μ thick electrically conductive thermal transfer recording material with a thickness of 3μ and no fourth layer was recorded under the same recording conditions as above, a dark image with an image density of 1.25 was obtained, but traces of scanning lines were visible on the high-quality paper. , the background was heavily stained and the image was unclear.

Claims (1)

[Scope of Claims] 1. A laminate having a four-layer structure, wherein (A) the first layer is made of metal powder and a resin matrix, the metal powder accounts for 5 to 60% by volume, and the surface resistance is 10 ⁵ ~10 ¹⁶ Ω, a metal-containing resin layer that is not destroyed by discharge during current recording; (B) The second layer is made of a metal thin film and has a surface resistance of 0.1
~1Ω, a conductive layer that is not destroyed by discharge during current recording; (C) A thermal transfer layer in which the third layer is composed of a colorant and a binder; (D) The fourth layer has a higher content than the third layer. 1. An electrically conductive heat-sensitive transfer recording material comprising a heat-sensitive transfer layer consisting of a colorant with a small amount and a binder, or only a binder, which are laminated in the above order. 2. The electrically conductive heat-sensitive transfer recording material according to claim 1, wherein the conductive layer comprises two or more metal thin films. 3. The electrically conductive heat-sensitive transfer recording material according to claim 1 or 2, wherein the heat-sensitive transfer layers (C) and (D) are formed into a net shape by gravure printing.