JPH0455875B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing multicolor thermal transfer recording paper.

(Prior art) In recent years, thermal transfer recording methods have become popular as an output method for various output terminals such as computers and facsimile machines due to their low noise, maintenance-free properties, simplicity of equipment, and the possibility of reducing size and weight. Development is progressing.

Thermal transfer recording paper has a thermally conductive substrate with
It is coated with a binder made of wax or other low-melting substance that softens or melts when heated, and is mixed with a coloring material. Printing is performed on a recording medium by printing in a pattern.

Yellow, red, indigo, ink, etc. 2 by the above thermal transfer method
When forming a multicolor image consisting of more than one color, prepare thermal transfer recording paper of these two or more colors, and transfer each color sequentially onto the same surface of the same transfer material to create a multicolor image. is formed.

Conventionally, a hot melt coating method has been used as a method for manufacturing thermal transfer recording paper of each color.

(Problems to be Solved by the Invention) In the conventional multicolor image forming method described above, when transferring with one thermal head, the thermal transfer recording paper is very soft, so these are sequentially transferred to the recording medium. There is a problem in that it is not possible to overlap with accurate positioning, and multicolor reproducibility is difficult. Further, when fixing thermal transfer recording paper of two or more colors and moving the transfer medium, there is a problem that two or more thermal heads are required and the simplicity of the apparatus is lost.

In order to solve these problems, a multicolor ink layer is formed by sequentially dividing two or more colors on the surface of a continuous base sheet, and then the transfer paper is moved continuously and a single heating head is used to print the ink. It is desirable to transfer multiple colors, but when using the gravure hot melt coating method to form an ink layer, the heated gravure roll comes into contact with the ink layer once formed, so the molten ink is transferred to the gravure roll. There is a problem that a good ink layer cannot be formed due to redeposition of the layer.

Therefore, an object of the present invention is to provide a multicolor thermal transfer recording paper that is useful for forming the above-mentioned multicolor images.

(Means for Solving the Problems) The above object has been achieved by the following present invention.
That is, in the present invention, ink for a heat-sensitive transfer layer of two or more colors consisting of an organic solvent containing a coloring material and dissolved wax is applied onto the surface of a continuous base sheet using a gravure printing machine at a temperature below the melting point of the wax. This is a method for producing a multicolor thermal transfer recording paper, which is characterized in that areas are repeatedly coated in sequence and dried.

(Function) By using two or more color inks made of an organic solvent solution containing a coloring material and dissolved wax to form the heat-sensitive transfer layer, the ink can be applied at a temperature below the melting point of the wax, so two colors can be applied. The above ink layer can be successively formed on the surface of a continuous base sheet by sequentially dividing it into sections using a gravure printing machine.

(Preferred Embodiments) Next, the present invention will be explained in more detail with reference to preferred embodiments.

The base sheet used in the present invention may be any material as long as it has a strength that will not stretch or tear during thermal transfer and will not be deformed or partially melted by the heat of the recording thermal head. Polyester, polypropylene, polystyrene, polycarbonate, polyimide and other plastic films, glassine paper, capacitor paper, ledger paper, Indian paper and other papers, metal foil, and aluminum-paper composite sheets that are composites of the above materials. , metallized paper or metallized film.

The heat-sensitive transfer ink layer formed on the surface of the base sheet is mainly composed of a coloring material and wax, and in the present invention, it is formed using an ink in which wax is dissolved in an organic solvent.

As the wax used, any conventionally known wax can be used, but since it is preferable to use an organic solvent with a relatively low boiling point, it is preferable to use a wax that is easily soluble in the solvent.

Waxes that are easily soluble in organic solvents include waxes that have ester bonds in their molecules.
As a specific example, as an ester wax,
WAX E, WAX F, WAX KPS and WAX BJ
As partially saponified ester waxes, WAX OP, WAX OM, WAX V and
One example is WAX GL3 (all manufactured by Hoechst). When using wax that is difficult to dissolve in organic solvents at room temperature, the ink is heated during application to dissolve the wax in the organic solvent. However, it should not be heated above the melting point of wax.

The solvent used in the present invention is a relatively low boiling point solvent used for conventional gravure inks, and specifically, toluene, xylene, trichlene, white spirit, ethyl acetate, acetic acid n
-butyl, isopropanol, n-butanol,
Examples include ethylcyclohexane.

The coloring material used in the present invention is selected from arbitrary organic and inorganic pigments or dyes in consideration of heat resistance, weather resistance, etc., and the additive used as necessary is mineral oil. , rapeseed oil, and other oils are used.

The relative amounts of each component used as described above may be the same as in conventionally known inks for forming a heat-sensitive transfer layer,
Further, as the ink application method, a gravure printing method using two or more gravure rolls for two or more colors is preferable.

There is no particular restriction on the material to be transferred when recording with the multicolor thermal transfer recording paper of the present invention, but it is preferable that the material has a highly smooth surface. For example, plastic film, paper, metal, wood, glass, fiber, etc. are used.

(Effects) According to the present invention as described above, by using two or more color inks made of an organic solvent solution containing a coloring material and dissolved wax to form a heat-sensitive transfer layer, Since ink can be applied, ink layers of two or more colors can be successively formed on the surface of a continuous base sheet by sequentially dividing the surface of the continuous base sheet using a gravure printing machine.

(Example) Next, the present invention will be described in more detail with reference to Examples.

Example 1 Transfer ink compositions of the following colors were applied to a continuous capacitor paper with a thickness of 10 μm at 5 g/m ² on a dry basis.
The multicolor thermal transfer recording paper of the present invention was obtained by repeatedly applying and drying the coated paper at room temperature (20° C.) for each color using a four-color gravure printing machine.

Hoechst WAX V 30 parts by weight Color Material 3 parts by weight Toluene 67 parts by weight The following materials were used as coloring materials.

Yellow ink; CI21090 Red ink; CI15850 Blue ink; CI74160 Black ink; Carbon black The above thermal transfer recording paper was combined with high-quality paper and passed through a printing machine equipped with a Toshiba thermal head under the conditions of an applied voltage of 12 V and an applied time of 2 msec. As a result, a multicolor image with good print quality was obtained.

Example 2 Transfer ink compositions of the following two colors were applied to a continuous polyester film with a thickness of 6 μm on a dry basis.
2 of the present invention was applied and dried at a rate of 2.5 g/m ² at 40°C using a two-color gravure printing machine.
A color thermal transfer recording paper was obtained.

Carnauba wax 20 parts by weight Parafine wax 150°F 10 parts by weight Color Material 3 parts by weight Toluene 67 parts by weight The following materials were used as coloring materials.

Red ink: CI15850 Black ink: Carbon black When the above heat-sensitive transfer recording paper was combined with high-quality paper and passed through a printing machine equipped with a Toshiba thermal head under the conditions of an applied voltage of 12 V and an application time of 2 msec., a red print with good quality was obtained. A black image was obtained.

Claims (1)

[Scope of Claims] 1. Two or more colors of ink for a heat-sensitive transfer layer consisting of an organic solvent containing a coloring material and dissolved wax are applied onto the surface of a continuous base sheet using a gravure printing machine at a temperature below the melting point of the wax. A method for producing multicolor thermal transfer recording paper, characterized by repeatedly coating and drying areas in sequence. 2. The method for producing multicolor thermal transfer recording paper according to claim 1, wherein the gravure printing machine is equipped with two or more gravure rolls corresponding to the number of hues of the ink.