JPH0325355B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording paper that can be recorded in two colors by a facsimile or similar device.

Conventionally, two-color recording using a facsimile or similar equipment has been carried out using, for example, thermal recording, in which two types of leuco dyes with different color development temperatures and color hues are combined with a color developer and various additives and coated in two layers on a support. Two-color recording is performed by changing the heating temperature of a thermal head in which heating elements are arranged linearly.
Possible color hue combinations include blue-red, black-red, and the like. However, when high-temperature colors such as black are developed, a low-temperature color such as red develops around the black dots, making it difficult to obtain clear image quality. to solve this problem,
Attempts have been made to apply a decoloring material that acts on the low-temperature coloring member when the temperature exceeds a certain level, but it has not yet been possible to eliminate the above-mentioned drawbacks.

The present invention eliminates this drawback, and includes an ink surface of an ink film coated on a support with an ink mixed with a thermoplastic material that is solid at room temperature and becomes liquid or viscous at high temperatures, and the hue of the ink. A coloring layer is formed by coating a coloring member on a support, which develops a color in a different hue and starts coloring at a lower temperature due to the melting point of the ink, and the coloring surface of the thermosensitive recording paper is layered in a removable manner. The present invention provides a two-color recording paper characterized by:

The heating temperature of the thermal head is changed according to the signal using a thermal head with heating resistors arranged from the back side of the thermal recording paper or the back side of the ink film.At high temperatures, the ink is transferred to the thermal coloring surface, and at low temperatures, the ink is transferred to the thermal recording paper. Recording is performed by coloring only the image. Next, by peeling the ink film from the thermal recording paper,
A clear image with two types of hues can be obtained. As mentioned above, an object of the present invention is to obtain a clear image recorded in two colors using one thermal head.

Next, the present invention will be explained with reference to the drawings.

FIG. 1 shows a partially enlarged sectional view of the two-color recording paper of the present invention, in which 1 is an ink film support, 2 is a thermoplastic member that is solid at room temperature, becomes liquid or sticky at high temperatures, and is colored. 3 is an ink film in which the ink layer 2 is coated on the support 1; a colored ink layer made of pigment or dye; 4 is a heat-sensitive layer which usually consists of a white or light-colored leuco dye, a color developer, and various additives, and develops a color different from the ink layer 2; 5 is a support of heat-sensitive recording paper; 6 is a support 5 with a color-forming member. This is a heat-sensitive recording paper on which a coloring layer 4 is formed by coating.

Recording is performed as described above from the back side of the heat-sensitive recording paper or the back side of the ink film of the two-color recording paper constructed in this manner, and the ink film is peeled off to obtain a two-color recorded image.

Next, materials used in the present invention will be explained.

As the support 1 of the ink film and the support 5 of the heat-sensitive recording paper, paper such as high quality paper, India paper, glassine paper, condenser paper, etc., or plastic film such as polyester film, polycarbonate film, etc. is used, and heat is applied from the support side. When recording with a head, the less loss of thermal energy in the support, the better, so the thickness of the support is preferably 50 μm or less.

The ink layer 2 is composed of waxes such as carnauba wax, ester wax, and polyethylene wax, polymers such as polymethyl methacrylate, polystyrene, butyral resin, and colorants such as carbon black, phthalocyanine blue, and rhodamine. This layer is made by mixing the following in appropriate proportions. The thermosensitive coloring layer 4 is a leuco dye,
It consists of a phenolic compound, a binder, and an additive, and the leuco dye is 3-diethylamino-6.
-Methyl-7-anilinofluorane (black coloring dye), 3-cyclohexylamino-6-chlorofluorane (yellow-orange coloring dye), 3-diethylamino-6-methyl-7-chlorofluorane (vermilion red coloring dye) ), etc., which produce various hues can be used. Examples of phenolic compounds include 4,4-isopropylidenediphenol, 2,2-bis(4
-hydroxyphenyl) n-heptane, 1,1-
bis(4-hydroxyphenyl)cyclohexane, etc.

As a binder, polyvinyl alcohol,
Starch, hydroxyethyl cellulose, styrene-maleic anhydride copolymer salts, styrene-butadiene latex, acrylate emulsion, and the like can be used. Additives include waxes such as paraffin wax, polyethylene wax, montan wax, amide wax, carnauba wax, and metal salts of fatty acids, and pigments such as calcium carbonate, clay, zinc oxide, aluminum oxide, and magnesium oxide. be.

As explained above, two-color recording is performed by overlapping the ink surface of an ink film on which ink mixed with a thermoplastic material is coated on a support and the color-forming surface of thermosensitive recording paper coated with a color-forming material different from the hue of the ink. Paper is prepared, but the melting point of the ink and the starting temperature of the coloring member must both be in the range of 40 to 150°C, and the former temperature must be higher than the latter, preferably 30°C or higher. Suitable records can be obtained when there is a temperature difference.

The melting point and coloring start temperature of the ink are measured using a differential thermal analyzer, for example, by the method described in Hirotaro Kobe, Kodansha, published in 1975, "Thermal Analysis", p. 15, and the endothermic main peak of the measurement curve is measured. The start point of endothermic extrapolation is taken as the melting point and color development start temperature.

Using this two-color recording paper, the heating temperature of the thermal head with heating resistors arranged from the back side of the thermal recording paper or the back side of the ink film is applied according to the signal, and at high temperatures, the ink is transferred to the colored side of the thermal recording paper. However, at low temperatures, only the thermal recording paper develops color. When recording at high temperatures, the thermal recording paper also develops color at the same time, but the transferred ink completely covers the colored area,
The two hues never mix. Also,
Only the heat-sensitive recording layer develops color at a temperature lower than this, but since the melting point of the ink is higher than the color-starting temperature of the heat-sensitive recording paper, ink transfer does not occur even if the heat-sensitive recording paper is heated until it reaches a practical density. . Therefore, the ink transfer image and the colored image on the heat-sensitive recording paper can be completely separated, and a clear recorded image without two-color bleeding can be obtained.

Next, the present invention will be explained using examples.

Example 1 Ink A Carnauba wax 9 parts by weight Carbon black 1 Ink B Polyethylene 4 parts by weight Oligostyrene 5 Carbon black 1 Toluene 50 Ink A was melted and mixed and applied to a 15 μm thick condenser paper using the hot melt method. The amount is 4g/m ²
Ink film A was prepared by applying the ink film so that the ink film A was obtained. In addition, a solution of ink B was applied to a 15 μm thick condenser paper using a wire doctor so that the coating amount after drying was 4.
The ink film B was prepared by applying the ink film at a concentration of g/m ² . The melting point of the ink layer is that of ink film A.
was 70°C, and ink film B was 110°C.

Next, thermal recording paper was produced using the following process.

Liquid 4,4-isopropylidene diphenol 3 parts by weight Stearamide 2 Hydroxyethyl cellulose (10% aqueous solution)
4 〃 Water 10 〃 Liquid 3-diethylamino-6-methyl-7-chlorofluorane 3 parts by weight Hydroxyethylcellulose (10% aqueous solution)
4 〃 Water 10 〃 The liquids were each dispersed in a ball mill for 3 hours, and the liquid was mixed at a ratio of 5 parts by weight to 10 parts by weight of the liquid to prepare a heat-sensitive paint. Apply this paint to a thickness of 25μ
A heat-sensitive recording paper with a red color was prepared by applying the mixture to a glassine paper of 80 g/m ² in an amount of 80 g/m 2 after drying. The temperature at which color development started was 65°C.

FIG. 2 shows the recording voltage-recording density characteristics of ink film A, ink film B, and thermal recording paper produced in this example at an application time of 8 m·sec. The vertical axis is the recording density, and the horizontal axis is the voltage applied to the thermal recording head used. The recording density of the thermal recording paper is determined when a 15 μm condenser paper is placed on the coloring side of the thermal recording paper and heated from the condenser paper side by a thermal head.

The ink side of the ink film A (melting point of the ink layer: 70°C) prepared as described above and the coloring side of the thermosensitive recording paper were superimposed, and the ink film was heated from the back side with an applied voltage of 16 V and an application time of 8 m·sec. When it was peeled off from the thermal recording paper, a black ink transfer image was obtained.

Next, when heated with an applied voltage of 14 V and an applied time of 8 m・sec., a red-colored image was obtained, but although some ink transfer occurred in the center of the red-colored dot, it can be easily distinguished from red for practical purposes. It was hot.

On the other hand, ink film B (ink layer melting point 110
Record voltage 17V, application time in the same way using
When the ink film was peeled off from the thermal recording paper by heating at 8 m·sec., an ink transfer image was obtained. At this time, the thermal recording paper is also colored red, but the black ink is transferred so as to completely cover the reddish areas, resulting in an apparently black image. Next, apply voltage 14V,
When heated for an application time of 8 m·sec., no ink transfer occurred and only a clear red colored image was obtained.

Example 2 The ink film B of Example 1 and thermal recording paper were superimposed, a thermal head was pressed from the back side of the thermal recording paper, and the paper was heated at an applied voltage of 15 V and an application time of 8 m·sec. to produce a recorded image with only red color. Obtained. Then the applied voltage
A black ink transfer image was obtained by heating at 17 V for an application time of 8 m·sec. As mentioned above, the temperature at which color development of the thermal recording paper starts is lower than the melting point of the ink, preferably 30°C.
By selecting the recording conditions with the above-mentioned differences, it is possible to obtain a clear two-color image in which the two hues do not mix.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the two-color recording paper of the present invention, Figure 2 is a cross-sectional view of the two-color recording paper of the present invention;
The figure is a graph showing the relationship between the voltage applied to the thermal head and the recording density for an application time of 8 m·sec. 1... Ink film support, 2... Ink layer, 3... Ink film, 4... Thermosensitive coloring layer,
5...Support for thermal recording paper, 6...Thermosensitive recording paper.

Claims (1)

[Claims] 1 The ink surface of an ink film coated on a support with an ink mixed with a thermoplastic material that is solid at room temperature and becomes liquid or viscous at high temperatures, and the ink surface is colored with a hue different from that of the ink, and the melting point of the ink is A two-color recording paper characterized in that the color-forming surfaces of thermosensitive recording paper, each of which has a color-forming layer formed by coating a support with a color-forming member that starts coloring at a lower temperature, are removably superimposed on each other.