JPH03151271A - Heat transfer recording medium - Google Patents

Abstract

PURPOSE:To prevent density jump and ink running, etc., from happening and improve the tone characteristic properties of an ink by a method wherein a heat transfer ink which is applied on a substrate in islands state or net state is transferred onto a body to be transferred while keeping the state. CONSTITUTION:A heat transfer ink 1 which is applied on a substrate 5 in islands state or net state is transferred onto a body to be transferred while keeping the state. Preferably, the ratio of the application area of the ink which is applied on the substrate to the whole area of the substrate is made to be 40-95%. By doing this, linking and running, etc., of the ink can be prevented from happening, and excellent tone characteristic properties from a low density to a high density can be obtained, and a clear image over a wide color reproduction range can be obtained.

Description

[Detailed Description of the Invention] E Not for industrial use! .] The present invention relates to a thermal transfer recording medium V' used in a recording apparatus using a thermal transfer method.

[Prior Art] Thermal transfer recording screws used in conventional thermal transfer printers are
In order to transfer ink sharply and reproducibly to the transfer target during thermal transfer, we select a binder that instantly melts and reduces viscosity at a certain temperature, and then add coloring materials such as pigments and dyes to it and disperse it. The heat-melting ink is processed to form a heat-melting ink, and the heat-melting ink is coated onto a base material in a uniform film thickness, or as in Japanese Patent Application No. 59-224389, thickening of the ink and bonding of the ink are prevented. In order to prevent this, the heat-melting ink was applied in scattered spots.

[Problem to be Solved by the Invention 1] However, in the thermal transfer recording medium of the prior art described above, when three-color inks of yellow, magenta, and cyan are created and a full-color image is printed by sequential thermal transfer of three color planes, the ink If the ink is coated with an even film thickness, the ink will not cut easily and the gradation characteristics will deteriorate due to the density jump from medium density to high density, resulting in an unclear image with a narrow color expression range. There was a problem with this.

Even if the shape of the ink is dotted to make the ink run in different directions, if the ink is crushed and deformed during transfer, good gradation may not be achieved due to connections between dots, ink flow, etc. was not obtained.

Therefore, the purpose of the present invention is to prevent density jumps, ink flow, etc., improve the gradation characteristics of ink, and improve the color reproduction range when printing color images using the multicolor plane sequential method. The purpose of the present invention is to provide thermal transfer that allows clear images to be obtained.

[Means for Solving the Problems] The thermal transfer recording medium of the present invention is capable of transferring a thermal transfer ink coated on a base material in the form of ladder islands or a mesh onto an object to be transferred while maintaining the shape. It is characterized in that the ratio of the area of the ink coated on the base material to the total area of the base material is preferably 40 to 95%.

[Function] According to the thermal transfer recording medium of the present invention which does not have the above characteristics, 1. Since the ink is transferred while maintaining the shape of scattered islands,
It can prevent ink connections and smudges, provide excellent gradation characteristics from low to high densities, and provide clear images with a wide color reproduction range.

[Example 1] The following examples and comparative examples ε: The present invention will be explained more specifically.

Tables 1 to 4 show ink composition examples of three colors, yellow, magenta, and cyan, of examples of the thermal transfer ink of the present invention. However, the numbers in the table indicate parts by weight.

The thermal transfer ink was prepared using the following procedure.

First, the above ink composition is added to a solvent in which the above composition can be dissolved or uniformly dispersed, and mixed by stirring.

Next, a coloring material was added and dispersed in a ball mill for 18 hours.
Uniform dispersion of each binder and coloring material was confirmed and the ink was prepared.

The method for producing the thermal transfer ink of the present invention is not limited to the above-mentioned solvent method, but can also be produced by a hollow melt method, an emulsion method, or the like.

As a comparative example of the thermal transfer ink of the present invention, Table 5 shows ink composition examples of three colors, yellow magenta and cyan, which exhibit a rapid melting phenomenon at 68°C.

Table 1 (Example 1) EVA: Ethylene vinyl acetate copolymer EEA: Ethylene ethyl acrylate copolymer Table 2 (Example 2) Table 3 (Example 3) Table 4 (Example 4) 1 -'1 Table (Comparative Examples j, ) The thermal transfer recording media of Examples and Comparative Examples were manufactured by the following method.

First, as shown in Figure 1, the solvent-dispersed ink prepared as described above was applied to a base material of 5PET (poly,
6 Next, the solvent in the ink is removed by heat drying or vacuum drying to form an ink layer 1 (thickness 0).
．． 5.3 μm) to form a thermal transfer recording medium.

When creating a color image, the thermal transfer recording medium of the present invention can be used in addition to the one in which a plurality of inks are coated on the same substrate as shown in FIG. It doesn't matter if it has multiple lines.

In the examples of the present invention, toluene was used as a solvent, but the present invention is not limited to this. Organic solvents such as , methanol, carbon tetrachloride, etc., or water may be used alone or in combination.

Polymers that can be used in the thermal transfer ink of the present invention include acrylic resin, polyurethane, polyvinyl acetal, polyamide, nylon, rosin resin, polyethylene, polycarbonate, vinylidene chloride resin, polyvinyl acetal, cellulose resin, Examples include ebogishi resin, e-acid vinyl resin, and vinyl chloride resin.

In addition to the above waxes, waxes that can be used in the present invention include montan wax, alcohol wax, synthetic oxidized wax, α-olefin/maleic anhydride copolymer, animal and vegetable waxes, and lanolin.

In addition to the above-mentioned organic pigments, coloring materials that can be used in the present invention include inorganic pigments, dyes, carbon black, and the like.

FIG. 2 schematically shows the structure of the thermal transfer recording medium of Examples 1 to 4 of the present invention, and the ink coverage on the grass surface of the obtained thermal transfer recording medium is also shown.

FIG. 3 shows the structure of a thermal transfer recording medium of Comparative Example J of the present invention. As shown in the figure, this thermal transfer recording medium is obtained by coating the ink of Comparative Example 1, which exhibits a steep viscosity decrease, on a base material so that the area coverage ratio is approximately 75%.

FIG. 4 shows the structure of a thermal transfer recording medium of Comparative Example 2 of the present invention. As shown in the figure, this thermal transfer recording medium is obtained by coating the ink of Example on a base material so that the area coverage is approximately 100%.

FIG. 5 shows the structure of a thermal transfer recording medium of Comparative Example 3 of the present invention. As shown in the figure, this thermal transfer recording medium was obtained by coating the ink of Example 1 on a base material so that the area coverage was approximately 30%.

Figure 6 shows the original transcription #! A schematic diagram showing a printing mechanism using a thermal head using a medium.

The thermal transfer recording medium 2 produced by the above method is in contact with the heating element 3 of the thermal head on the surface not coated with the thermal transfer ink 1, and the surface coated with the thermal transfer ink is in contact with the printing paper 4.
come into contact with. In this state, the heating element 3 of the thermal head generates heat according to the printing information 1, and the thermal energy is transmitted to the thermal transfer ink layer 1 via the base material 5, softening the ink, and only the softened portions are dotted in the form of islands. The image is formed by transferring the image onto the photographic paper 4 through the transfer dots 6 while maintaining its original shape.

However, unless the deformation is to the extent that the ink is crushed and the dots are connected, the slight deformation of the ink layer shape has no effect on the transfer characteristics.

Next, a printing test was conducted using the above thermal transfer recording medium. The print test was conducted using a three-color superimposed print using a thermal head.

The print pattern was a density gradation pattern of 16 horizontal stripes on smooth paper. The printing energy is set to i11 so that the 14th gradation has full density when the first color is transferred.
It was set to a constant value such that excess energy was applied to gradations of 15 and above. Next, to evaluate the transferability, the transfer density for each gradation was measured by the reflection OD value using a complimentary color filter using Maebeth-T R-927 manufactured by Koll morgan. It was measured.

The evaluation results of gradation of the present example and comparative example are shown below. In the figures below, the vertical axis represents the reflection OD normalized to the maximum OD value of 1°0, and the horizontal axis represents the transfer energy.

FIG. 7 shows the gradation of magenta in the example: +, =4, ] color.

FIG. 8 shows the gradation of two-color cyan in Examples 1 to 4.

FIG. 9 shows the gradation of three-color yellow in Examples 1 to 4.

FIG. 10 shows the magenta gradation of one color overlap in Comparative Examples 1 to 3.

FIG. 11 shows the two-color cyan gradation properties of Comparative Examples 1 to 3.

FIG. 12 shows the three-color yellow gradation properties of Comparative Examples 1 to 3.

As shown in FIGS. 7 to 9, the thermal transfer inks of Examples 1 to 4 have excellent gradation from the low printing energy range to the high printing energy range, and can be applied with high printing energy. No ink flow phenomenon occurred even in the high concentration range.

On the other hand, as shown in Figures 10--12,
The ink of Comparative Example 1.2 had poor ink transferability in the low density range, and also had a rapid increase in density from medium density to high density. Furthermore, with the ink of Comparative Example 1, scumming occurred on the entire print surface, and an ink flow phenomenon occurred in the high density region.

Furthermore, the ink of Comparative Example 3 had a small amount of ink transferred, and 1
I couldn't get enough concentration.

Next, using the 7 types of thermal transfer inks mentioned above, 6 colors of 64
As a result of printing a full-color image by superimposing three-color gradation transfer, the image using the thermal transfer recording medium of Examples 1-4 has a wide range of color expression. 11 A bright and clear image was obtained.

Moreover, the image using the thermal transfer recording medium of Comparative Example 1-3 was
The color expression range was narrow, and image quality deterioration phenomena such as roughness due to density jumps, ink flow, background smearing, and insufficient density were observed.

From the above results, when printing full-color images, there are no image quality deterioration phenomena such as roughness, ink flow, background smudges, lack of density, etc., and high image quality with excellent gradation, clarity, and a wide range of color expression can be achieved. (1) Because of this, there is a clear thermal melting phenomenon in a specific temperature range on the floor or base material. The ratio of the coated area of the ink coated on the material to the total base material area is 40 to 9
It is effective to use a thermal transfer recording medium with 5% r.

Furthermore, although this embodiment has been described with respect to 30 superimposed images using a thermal head, the present invention is not limited thereto, and can also be applied to an electric thermal transfer method and other thermal transfer methods.

Furthermore, in this embodiment, three colors of yellow, magenta, and cyan are used.
Although a color image composed of colors has been described, the present invention is not limited to this, and the present invention is not limited to this.
It is also possible to apply the present invention to color printers, monochrome printers, and two-color printers.

[Effects of the Invention 1] As explained above, if the thermal transfer recording medium of the present invention is used, good gradation can be obtained in all density ranges when printing full-color images, etc., and 8) Color expression iii) Tsukikawa 0 The effect of being able to have a wide high image quality 1-41
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[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the structure and transfer principle of a multi-color thermal transfer recording medium of the present invention. FIG. 2 is a schematic diagram showing the structure and transfer principle of a monochrome thermal transfer recording medium of the present invention. Fig. 3 is a sectional view showing the structure of a thermal transfer recording medium according to an example of the present invention. Fig. 4 is a sectional view showing the structure of a thermal transfer recording medium of Comparative Example 1 of the invention. A cross-sectional view showing the structure of a thermal transfer recording medium of Comparative Example 2 of the present invention. Fig. 6 is a cross-sectional view showing the structure of a thermal transfer recording medium of Comparative Example 3 of the present invention. Fig. 7 is a cross-sectional view showing the structure of a thermal transfer recording medium of Comparative Example 3 of the invention. A schematic diagram showing a printing mechanism using a thermal head using a thermal transfer recording medium. Fig. 8 shows the correlation between printing energy and transfer density showing the gradation of magenta ink, which is one color of the ink of the example of the present invention. Figure 9 is a correlation diagram between printing energy and transfer density showing the gradation of cyan ink, the second color of the ink of the example of the present invention. Figure 10 is the correlation diagram of the third color of the ink of the example of the present invention. Fig. 11 is a correlation diagram between printing energy and transfer density showing the gradation of magenta ink, the first color of ink of a comparative example of the present invention. Fig. 12 is a correlation diagram between printing energy and transfer density showing the gradation of cyan ink, which is the second color of the ink of the comparative example of the present invention. Fig. 13 is the yellow, which is the third color of the ink of the comparative example of the present invention. Correlation diagram between printing energy and transfer density showing the gradation of 1... Thermal transfer ink 2... Thermal transfer recording medium Heating element Photographic paper support Heated and transferred ink Thermal head Heating element Platen or higher

Claims (2)

[Claims] (1) A thermal transfer recording medium characterized in that a thermal transfer ink coated on a substrate in the form of islands or meshes is transferred onto an object to be transferred without changing the shape. (2) Coated area of thermal transfer ink coated on the base material,
The thermal transfer recording medium according to claim 1, characterized in that the ratio to the total area of the base material is 40 to 95%.