JPS59165694A - Color thermal transfer paper - Google Patents

Abstract

PURPOSE:To obtain a color gradation image with faithful reproduction of an original color tone, by a method wherein a white-colored thermal transfer ink is applied onto a base in one or more densities together with a plurality of thermal transfer inks. CONSTITUTION:In a color thermal transfer paper 3 comprising a plurality of thermal transfer inks of different colors (yellow Y, magenta M and cyan C) repeatedly applied on a thin base 1 (e.g., a plastic film or a condenser paper having a thickness of 2-25mum), a white-colored thermal transfer ink W is applied in one or more densities. USE:To be applied to a thermal printer or the like capable of color hard copying.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color thermal transfer paper that can be suitably used in thermal printers capable of color hard copying.

In recent years, the technology for using CRT displays in computer systems and the like has reached a high standard, and the use of color is gaining momentum. As a result, printers that make hard copies of color displays have been actively developed and have come into practical use. The main color hard copy methods can be roughly divided into impact and non-impact Niga methods. There is a wire dot method as an impact method, but it is noisy and
It has disadvantages such as slow printing speed and poor resolution. Non-impact methods include ink jet methods and thermal transfer methods, but the former is prone to ink clogging and other problems.
The disadvantage is that the maintainability of the device is poor. The present invention relates to color thermal transfer paper that can be suitably used in the latter thermal transfer method.

Regarding color thermal transfer paper, various patent publications can be found.

For example, JP-A-56-98190 discloses a color thermal transfer ribbon in which two or more types of thermal transfer ink layers of different colors are formed on a base material.

If the three primary colors of yellow, magenta, and cyan are used as the thermal transfer ink for the color thermal transfer ribbon, any two
Red, green, and blue-violet are formed by combining the seeds, and black is formed by combining the three colors. That is, based on the color signal, a heating head heats the thermal transfer ribbon to melt the thermal transfer ink and transfer it onto plain paper. For example, layer the colors in the order of yellow, magenta, and cyan. After printing one color, the plain paper is moved so that it overlaps with the next color, and then the second color is printed. In this way, printing in seven colors can be achieved by using wrinkled thermal transfer paper coated with three colors of ink: yellow, magenta, and cyan.

In this method, reproduction of grayscale images and color images faithful to the original tones are achieved by adjusting the amount of ink transferred by changing the intensity of the pulse signal applied to the heating head. Although it is possible to obtain tones or gradation images of seven or more colors using this method, it has the drawback of poor print quality due to incomplete ink transfer. In order to improve printing quality, there are area gradation methods such as dithering that create pseudo gradations by changing the number of dots in each pixel, but they have the disadvantage of requiring the use of a head with higher resolution. .

JP-A-57-137190 discloses a thermal transfer for force 2, which is characterized by having an ink layer' on one side of a thin paper or film in which different colors are regularly and repeatedly formed in stripes with the same width. However, it is aimed at multi-color printing, and is not aimed at reproducing shading images.

The inventors of the present invention have conducted extensive research to develop a thermal transfer paper that produces color gradation images rather than multicolor printing.As a result, the inventors have found that thermal transfer ink of different colors is repeatedly painted on a thin substrate. Invented a color thermal transfer paper characterized in that it is necessarily coated with white thermal transfer ink at one or more densities. It was possible to obtain a color image that is faithful to the color tones without degrading print quality and without using the area gradation method.

The present invention will be explained in detail below.

FIG. 1 is a schematic cross-sectional view showing an example of conventional color thermal transfer paper. In this figure, 1 is the base material, Y, M, C!
2 shows yellow, magenta, and cyan thermal transfer ink layers, respectively, and 2 shows conventional color thermal transfer paper.

FIG. 2 is a sectional view showing an embodiment of the color thermal transfer paper of the present invention. In this figure, 1 indicates the thin base material %Y%M, OXW indicates yellow, magenta, cyan, and white thermal transfer ink layers, respectively, and 3 indicates the color thermal transfer paper of the present invention. 3 to 7 show examples of printing on the color thermal transfer paper of the present invention.

In FIG. 3, 4 indicates the image receiving paper, and D and V indicate the transferred yellow and white inks, respectively. This gave a pale yellow color. 4 in Figure 4 is image receiving paper, M', W
', Y' indicate transferred magenta, white, and yellow inks, respectively. This resulted in a red color close to striped magenta. In FIG. 5, 4 represents the image receiving paper, and W', C', and Y' represent the transferred white, cyan, and yellow inks, respectively. This gave a pale green color. 4 in Figure 6
indicates the image receiving paper, and C', W', and Y' indicate the transferred cyan, white, and yellow inks, respectively. This gave a green color close to dicyan. 4 in Fig. 7 is the receiving paper, f,
O', M', and Y' represent transferred white, cyan, magenta, and yellow inks, respectively. This gave a gray color.

FIG. 8 is a schematic cross-sectional view showing another embodiment of the present invention. Here, 1 is the thin base material, YXM, and 0 is the yellow, magenta, and cyan thermal transfer ink layers, respectively.
W, , W3 are thermal transfer ink layers having different white densities depending on the amount of white pigment used, and 5 is a color thermal transfer paper of the present invention.

In FIG. 9, 4 indicates the image receiving paper, Y indicates the transferred yellow ink, and W indicates the transferred white ink with different white densities. As a result, yellows with the same hue but different densities were obtained.

As the thin base material (1) of the present invention, a conventionally known thin base material with a thickness of 2 to 25 μm can be used as is, and although there are no particular limitations, measures to prevent sticking, wrinkles, and static electricity have been taken. It is more preferable that it is strained.

Examples of thin substrates include plastic films such as polyester and thin papers such as capacitor paper.

As the thermal transfer ink layer of the present invention, a conventionally known heat-melting colored ink layer can be used as is, and there are no particular restrictions. The thermally transferable colored ink layer used in the present invention is composed of colorants, waxes, resins, oils, etc., and preferably has a thickness of about 3 to 6 microns.

In the case of black coloring, carbon black, oil black, etc. can be used as the coloring agent.

In the case of magenta, cyan, and yellow, commonly used organic pigments, inorganic pigments, or dyes can be used.

For white, for example, Tie,, 0aOO,, At(
OH).

Inorganic white pigments such as urea-formalin resin and organic white pigments such as urea-formalin resin can be used.

Examples of waxes that can be used include paraffin wax, carnauba wax, microcrystalline wax, montan wax, wood wax, beeswax, rice wax, and low molecular weight polyethylene wax.

Examples of resins include ethylene copolymers, rosin derivatives,
Petroleum resin, styrene resin, etc. are used.

As the oil, mineral oil, vegetable oil, etc. are used.

[Brief explanation of the drawing]

FIG. 1 shows a sectional view of a conventional color thermal transfer paper, and FIGS. 2 and 8 show sectional views of the color thermal transfer paper of the present invention. 3 to 7 and 9 show examples of printing on the color thermal transfer paper of the present invention. 1: Base material 4: Receiving paper Y: Yellow thermal transfer ink layer M: Magenta thermal transfer ink layer C Nidian thermal transfer ink layer W: White thermal transfer ink layer, S1K Figure 2 Figure 3 Figure 4 @ Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1. A color thermal transfer paper in which thermal transfer inks of different colors are repeatedly smeared on a thin base material, wherein at least one of the thermal transfer inks is a white thermal transfer ink. paper. 2. The color thermal transfer paper according to claim 1, wherein two or more types of white thermal transfer ink are applied with different white densities.