JPH0454596B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a transfer type electrically conductive recording sheet for forming an image on a recording medium such as plain paper or plastic film.

[Prior art]

A method of forming an image on a sheet-like recording medium includes a method in which the recording medium itself has a coloring layer (this is called primary coloring) and images are directly formed according to energy information applied in various forms. , a method in which a latent image is once formed on a recording medium and then made visible using a developer such as toner, and a method in which an image is first formed on a transfer paper or the like and then transferred to a storage recording medium (this is a secondary method). color development), etc. Examples of the first method include discharge recording, electrolytic recording, and energization recording in which an image is formed using electrical energy from a recording needle, and thermal recording method in which an image is formed using thermal energy from a heat-sensitive head. The characteristics of these primary coloring methods are that the recording medium itself has a coloring layer, so the structure of the recording device is simple, making it easy to downsize and reduce the price. Since processing such as coating is required, the price of the recording medium is high and operating costs are high. Examples of secondary color development include electrostatic recording and electrophotography. The feature of this method is that if the toner transfer method is used, plain paper or plastic sheets can be used as the recording medium, so the operating cost is low and there is a wide range of recording media to choose from.However, on the other hand, the structure of the recording device is complicated. in,
The disadvantage is that it is difficult to downsize and lower the price.

As mentioned above, with conventional recording methods, there is a conflict between the miniaturization and cost reduction of recording devices and the operating costs. A method was desired.

In order to overcome the above-mentioned drawbacks, transfer type heat-sensitive recording methods have also been considered, but generally the recording time is long.

In addition, examples of what has been considered include, for example,
There is a heat generating sheet for transfer described in Publication No. 53-074047. FIG. 1 shows a cross-sectional view of a conventional transfer heating sheet. That is, the heat generating sheet 1 for transfer is composed of an electrical resistance layer 2, a conductive layer 3, and an ink layer 4.

FIG. 2 shows a configuration diagram of a recording apparatus when recording the heat-generating transfer sheet 1 on plain paper 5. That is, the heat generating sheet 1 for transfer and the plain paper 5 are overlapped,
By passing the current from the recording signal generator 7 through the recording electrode 6, the electric resistance layer 2, the conductive layer 3, and the return electrode 8, the electric current is converted into Joule heat in the electric resistance layer 2 directly under the recording electrode, and the ink is heated. The vehicle in layer 4 is melted and the ink is transferred to plain paper 5 to form an image. Also, Unexamined Patent Publication 1973-
Current-carrying recording material of Publication No. 95594 and JP-A-58-
In the recording material for electrical transfer disclosed in Publication No. 25992, what is transferred to, for example, a plain paper recording medium by electrical current is a semiconductive resin layer (Japanese Patent Laid-Open No. 55
-95594) and ink layer (Japanese Unexamined Patent Publication No. 1983-
25992)) are the pigment, low melting point resin, and wax. Recording using the above-described current-carrying recording material, current-carrying transfer recording material, and heat-generating sheet for transfer has the advantage that the recording time can be drastically shortened. In other words, the so-called heat-sensitive recording heads that have been used in conventional heat-sensitive recording methods have a wear-resistant layer on top of the resistive layer, and the substrate is made of ceramic, so that heat dissipation and conduction are prevented. The efficiency was extremely poor and required several milliseconds of heating time, but by using the heat-generating sheet for transfer, the heat conduction efficiency improves and printing becomes possible in just about 0.5 milliseconds of energization time. It is. However, these use pigments, and as the pigments, low-melting point resins, and wax are transferred to the recording medium by applying electricity, it takes two to three uses to provide a print with a reflection density (OD) of 0.5 or higher. Furthermore, the reflection density rises rapidly with respect to the applied voltage, making it impossible to record gradations.

[Summary of the invention]

The present invention was made to eliminate the drawbacks of the above-mentioned conventional sheets, and an object of the present invention is to obtain a transfer-type current-carrying recording sheet that is capable of multiple printing, high-speed printing, and gradation recording.

[Embodiments of the invention]

FIG. 3 shows a cross-sectional view of a transfer type electrically conductive recording sheet according to an embodiment of the present invention. That is, the transfer type current recording sheet 9 is composed of an electrical resistance layer 2, a conductive layer 3, a backing material 10, and a resin material layer 11 containing a dye and a material that dissolves the dye when heated.

The electrical resistance layer 2 forming the heating layer of the present invention is made of a resin such as polybutyral resin and polyurethane, and a conductive material such as carbon black and conductive zinc oxide, and the blending ratio is 100 parts by weight of the resin. Conductive material for 10
It is preferable to use ~200 parts by weight. If it is less than 10 parts by weight, the electrical resistance is too high and it generates heat (80 to 120℃).
A high voltage (20 to 30 V) is required to do this, and discharge is likely to occur, and if the amount exceeds 200 parts by weight, the coating film becomes brittle.
The electrically resistive layer can be obtained by mixing the resin and conductive material in a suitable solvent such as alcohol, applying the mixture, and drying the mixture.

The conductive layer 3 forming the heating layer of this invention is made of, for example, an aluminum sheet, and the backing material 10 may be omitted, but since it is easily torn, 0.01 to 0.5 of aluminum is used on the backing material 10, such as a polyethylene terephthalate sheet. Preferably, it is obtained by .mu.m vapor deposition.

The resin material layer of the present invention is made by scouring a material containing a dye, a material that dissolves the dye when heated, and a resin in a ball mill with a suitable solvent such as water, applying it to a backing material, etc. using a wire bar, and drying it. can be obtained.

As the resin, for example, polyvinyl alcohol,
Water-soluble polymers such as polyvinylpyrrolidone, polystyrene sulfonic acid, polyacrylic acid, polymethacrylic acid, polyvinylpyridine, gelatin and gum arabic, and oil-soluble polymers such as polymethyl methacrylate are used.

As the dye, for example, anthraquinone-based and azo-based dispersible sublimable dyes are used, and the blending ratio thereof is preferably 1 to 16 parts by weight per 8 parts by weight of the resin. If it is less than 1 part by weight, the reflection density (OD) of the print will be too low, and if it is more than 16 parts by weight, the coating will become brittle.

Carnauba wax and glycerin are used as the material that dissolves the dye during heating, and the blending ratio thereof is preferably 10 to 30 parts by weight per 8 parts by weight of the resin. If it is less than 10 parts by weight, the reflection density (OD) of the print will be low, and if it is more than 30 parts by weight, the coating film will be sticky.

Further, when a surfactant is further added to the resin material layer, there is an advantage that the sensitivity of the transfer type current recording sheet is improved, so it is preferably used. As the surfactant, for example, sorbitan fatty acid esters are used, and sorbitan monopalmitate and sorbitan monostearate, which are solid at room temperature, are particularly preferably used. The mixing ratio thereof is preferably 1 to 20 parts by weight per 8 parts by weight of the resin. If it is less than 1 part by weight, the reflection density (OD) of the print will be low, and if it is more than 20 parts by weight, the background fog will be large.

This transfer recording is carried out in the following manner using the transfer type electrification recording sheet of the present invention constructed as described above. That is, using a device as shown in FIG. 2, the current from the recording signal generator is converted into Joule heat, and this heat is transmitted from the conductive layer to the backing material to the resin material layer. Since dyes are used in this invention instead of conventionally used pigments, the heat that has arrived will dissolve the dye in the material that dissolves the dye by heating, and if a surfactant is added, the dye will be dissolved in the surfactant. The liquid mixture is transferred onto the surface of a recording medium. At this time, in the resin material layer, a liquid mixture is moving through the solid resin and is eluted to the recording medium, but only a portion of the mixture is eluted due to its adsorption to the resin. Therefore, it can be used repeatedly many times.
Furthermore, since the rate at which the mixture containing the dye is eluted is proportional to the amount of current applied, gradation properties can also be obtained.

EXAMPLES The present invention will be explained in detail with reference to Examples below, but the invention is not limited thereto.

Example 1 5.4 parts by weight of carbon black, butyral resin
10 parts by weight and 90 parts by weight of ethanol are kneaded overnight in a ball mill. This kneaded material is applied to the aluminum-deposited side of a 12-μm polyethylene terephthalate sheet on which 0.05-μm of aluminum is deposited using a wire bar to a thickness of 5 μm, and dried. Separately, 8 parts by weight of PVA, 8 parts by weight of an azo sublimable dye (manufactured by Hodogaya Chemical, trade name OH-Blue), 10 parts by weight of surfactant sorbitan monopalmitate, 20 parts by weight of glycerin, and 100 parts by weight of water. Knead in a ball mill all day and night. This material is coated on the non-evaporated surface of the polyethylene terephthalate sheet to a thickness of 5 μm and dried to obtain a transfer type current recording sheet. Layer this sheet with high-quality paper, apply voltage 8V, pulse frequency 100Hz, pulse application time.
When recording was performed with an electrode at a paper feed rate of 16 mm/s for 0.5 ms, the reflection density (OD) of the print was 0.9.

Comparative Example 1 A transfer type electrical recording sheet was obtained in the same manner as in Example 1, except that 20 parts by weight of 3,5-dinitrotoluene was used instead of 20 parts by weight of glycerin. When this sheet and high-quality paper were overlapped and recorded in the same manner as in Example 1, the reflection density (OD) of the print was 0.95, indicating that there was no overlap printing.
When the printing was repeated 10 times, the reflection density (OD) of the printing significantly decreased to 0.13, and it was found that the printing was not suitable for repeated printing.

Example 2 5 parts by weight of conductive zinc oxide, 10 parts by weight of polyurethane, 45 parts by weight of methyl ethyl ketone, and 45 parts by weight of toluene were kneaded overnight in a ball mill. This kneaded product was applied to a 10 μm thick aluminum sheet to a thickness of 5 μm and dried. In addition, 10 parts by weight of polyvinylpyrrolidone, 16 parts by weight of anthraquinone-type sublimable dye (manufactured by Mitsubishi Kasei, trade name PTB-77), and 6 parts by weight of surfactant sorbitan monostearate.
15 parts by weight of glycerin and 100 parts by weight of water are kneaded overnight in a ball mill. This material was coated on the back side of the above-treated aluminum sheet to a thickness of 5 μm using a wire bar and dried to obtain a transfer type current recording sheet. When this sheet and high-quality paper were stacked together and recorded using electrodes at an applied voltage of 10 V, a pulse frequency of 100 Hz, a pulse application time of 1 ms, and a paper feed speed of 16 mm/s, the reflection density (OD) of the print was 1.1.

Furthermore, when recording is performed using the above-mentioned transfer-type current-carrying recording sheet, FIG. 4 shows the change in the reflection density (OD) of the print depending on the applied voltage (V). As you will see, recording has gradation.

Furthermore, the change in the reflection density (OD) of the print when the above-mentioned transfer-type electrification recording sheet is used repeatedly is measured in the fifth column.
As shown in the figure. As you will see, this recording sheet can be used about 10 times.

〔Effect of the invention〕

As explained above, by using the transfer type current recording sheet of the present invention, it is possible to suitably perform multiple printings, high-speed printing, and gradation recording.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a conventional heat-generating sheet for transfer, Fig. 2 is a configuration diagram of a recording device using a general heat-generating sheet for transfer, and Fig. 3 is a transfer-type energization recording device according to an embodiment of the present invention. FIG. 4 is a cross-sectional view of the sheet, and FIG. 4 is a characteristic diagram showing changes in the reflection density (OD) of printed characters depending on the applied voltage (V) in recording using a transfer-type current-carrying recording sheet according to an embodiment of the present invention. FIG. 2 is a characteristic diagram showing changes in the reflection density (OD) of prints when the transfer type current recording sheet of one embodiment of the present invention is repeatedly used. In the figure, 1 is a heat generating sheet for transfer, 2 is an electrical resistance layer, 3 is a conductive layer, and 2 and 3 constitute a heating layer. 4 is an ink layer, 5 is plain paper, 6 is a recording electrode,
7 is a recording signal generator, 8 is a return electrode, 9 is a transfer type energized recording sheet, 10 is a packing material, and 11 is a resin material layer. Note that the same reference numerals in each figure indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. A resin material layer containing a dispersible sublimable dye and at least one of carnauba wax and glycerin as a material that dissolves the dye when heated, and an electric current provided in the resin material layer. A transfer type electrically conductive recording sheet comprising a heating layer that heats the resin material layer. 2. The transfer type electrical recording sheet according to claim 1, wherein the heating layer is composed of an electrical resistance layer and a conductive layer.