JPH11105442A - Many times thermal transfer recording medium to be used - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve uniformly high printing density and high printing quantity even in the use in many times by furnishing a transfer control layer consisting of a film forming resin component having a nonheat-softening property or a high softening point, a releasing resin component, and a nonheat soluble fine particles on the upper surface of a heat melt ink layer. SOLUTION: As a film forming resin component, resin is used which has a nonheat-softening property and a high softening point, concretely, one kind or a plurality of vinyl chloride-vinyl acetate resin, vinyl chloride resin, or the like having a softening point of at least 130 deg.C. Also, for the film forming resin component, one kind or a multiplicity of releasing resin components such as silicone resin, silicone modified resin, and fluorocarbon resin are used for the purpose of having a releasing effect relative to heat melt ink and image receiving paper. In addition, for the nonheat melt fine particles, fine particles which do not soften and decompose by factors of heat, pressure or the like are used, and one kind or more of silicone fine particles, fluorocarbon fine particles, and the like are mixedly used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording medium,
More specifically, the present invention relates to a thermal transfer recording medium for multiple times.

[0002]

2. Description of the Related Art In thermal transfer recording methods for recording apparatuses such as facsimile machines and various printers, the miniaturization and cost reduction of recording apparatuses have become extremely widespread, and the demand for thermal transfer recording media used therein has been steadily increasing. I have. However, the conventional thermal transfer recording medium has a heat-fusible ink layer on a support.
Generally, one or two layers are provided. In these thermal transfer recording media, the heat-fusible ink at the location heated and pressed by the thermal head is all transferred to the image receiving paper side.

[0003] Therefore, it is difficult to use these thermal transfer recording media many times in the same place, and the amount of use of the thermal transfer recording media increases, and there is a problem in running cost.
In addition, there has been a problem in recent environmental problems and wastes, and a thermal transfer recording medium that can be used repeatedly at the same place, that is, a large number of times, has been demanded.

Therefore, various thermal transfer recording media of various types have been proposed so far. Some of them are as follows: (1) A plurality of adhesive layers and a hot-melt ink layer are provided on a support;
A method of transferring the heat-meltable ink little by little, (2) a method of providing an ink layer made of a heat-meltable ink and a non-thermosoftening porous forming resin on a support and exuding the hot-melt ink little by little And (3) a method of providing an ink layer composed of a heat-meltable ink and a supercooled component incompatible with the ink on a support, and transferring the ink little by little by delamination due to cohesive failure of the ink layer. ing.

[0005] However, the thermal transfer recording medium of the above (1) has a disadvantage that the transfer of ink is not constant with the number of times of printing. The thermal transfer recording medium of the above (2) has a drawback that the amount of oozing out of the ink decreases with the number of times of printing and the density decreases sharply. In the thermal transfer recording medium (3), the cohesive failure of the ink layer is unstable depending on the printing environment temperature. In addition, since the method of transferring ink by delamination is used, there is a disadvantage that ghost is generated due to the flash of ink due to delamination.

In order to eliminate these disadvantages, Japanese Patent Laid-Open No.
As disclosed in JP-A-246156 and JP-A-6-64340, a heat-meltable ink layer is provided on a support, and a transfer control layer containing heat-meltable fine particles is further provided thereon to form a heat-meltable ink layer. There has been proposed a method of controlling the outflow amount of the volatile ink. However, in the thermal transfer recording medium according to this method, since the heat-fusible fine particles contained in the transfer control layer are transferred to the image receiving paper in the first printing, transfer unevenness occurs in an image formed in the second and subsequent printings. There are drawbacks.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to overcome the disadvantages of the prior art and to provide a multiple-time thermal transfer recording medium capable of obtaining uniform high print density and high print quality even when used multiple times. With the goal. It is another object of the present invention to provide a thermal transfer recording medium which is prevented from being soiled or ghosted due to ink flapping due to multiple use.

[0008]

Means for Solving the Problems The inventors of the present invention have solved the above-mentioned problems, and have conducted intensive studies in order to obtain a thermal transfer recording medium which can obtain high print density and high print quality even when used many times. A transfer control comprising a non-thermosoftening or high softening point film-forming resin component, a release resin component and non-thermofusible fine particles, which can control the transfer of the hot-melt ink to the upper layer of the hot-melt ink layer. It has been found that the problem can be solved by providing a layer and the transfer control layer having a releasing effect on the heat-fusible ink and the image receiving paper.

Hereinafter, the present invention will be described in more detail. The transfer control layer has non-thermal fusible fine particles contained in the resin for forming the transfer control layer, the thermal expansion of the heat fusible ink due to the heat from the thermal head, the pressure between the thermal head and the platen, and a substantially uniform hole due to the capillary phenomenon. The hot-melt ink exudes from this hole and has non-heat-meltable fine particles, so that the transfer control layer forming resin and the image receiving paper do not completely adhere to each other, so that a sufficient amount of ink in terms of print density can be melted. Exudes in a state. All of the exuded ink in the heat-melted state is cooled and solidified on the image receiving paper side because the transfer control layer has a releasing effect, and high-density high-quality printing is obtained. In addition, due to these effects, the fusing of the heat-fusible ink does not occur at the time of transfer, and background dirt and ghost due to pressure-sensitive transfer at the time of multiple use do not occur.

Regarding the control of the heat-fusible ink in the transfer control layer, when the heat-fusible ink exudes due to the presence of the non-heat-fusible fine particles, the transfer control layer transfers the heat-fusible ink to the heat-fusible ink on the support side via the transfer control layer. Since the contact area with the control layer forming resin is larger than that of the exuded heat-fusible ink and the transfer control layer forming resin, even if the heat-fusible ink is cooled and solidified, the transfer control layer forming resin does not have heat on the support side. It remains on the fusible ink side and continues to be controlled many times without transferring all.

As the film-forming resin component used in the present invention, a resin having a non-thermal softening property or a high softening point is used. Specifically, a vinyl chloride-vinyl acetate resin having a softening point of 130 ° C. or more, vinyl chloride, Resin, polyvinyl butyral resin, polyvinyl acetal resin, polyester resin,
One or more of acrylic resin, styrene-maleic acid resin, cellulose resin and the like are used.

In addition, the above-mentioned film-forming resin component has a releasing resin component such as a silicone resin, a silicon-modified resin, a fluorine-based resin, etc., for the purpose of having a releasing effect on the hot-melt ink and the image receiving paper. One or more of these are used.

As the non-thermofusible fine particles used in the present invention, fine particles which do not soften or decompose due to factors such as heat and pressure are used. Specific examples thereof include silicon fine particles, fluorine fine particles, and melamine fine particles. , Silicon dioxide or the like, or a mixture thereof.

The average particle diameter of the non-heat-meltable fine particles is 0.5 μm to 5 μm. If it is smaller than this, the transfer control layer forming resin and the image receiving paper are completely adhered to each other, and the density of the ink is insufficient. The exuded hot-melt ink is solidified by cooling without contacting the image receiving paper, resulting in poor transfer. In order to obtain higher density and higher quality printing, it is preferable to use fine particles having an average particle diameter of 2 μm to 4 μm.

The weight ratio of the entire resin in the transfer control layer to the non-heat-meltable fine particles is preferably transfer resin-forming resin: non-heat-meltable fine particles = 75: 25 to 25:75. When the amount of the non-heat-fusible fine particles is 25% or less, sufficient holes are not opened in the resin for forming the transfer control layer, resulting in insufficient concentration or poor transfer. Is weakened and is transferred to the image receiving paper side together with the hot-melt ink, and the entire transfer occurs in the second and subsequent printings.

The coating amount of the transfer control layer is as follows:
It is preferably from 0.05 g / m 2 to 1.0 g / m 2. At 0.05 g / m 2 or less, the transfer cannot be completely controlled, and the entire image is transferred. At 1.0 g / 8 m 2 or more, the print density is reduced. More preferably, the total coating amount of the heat-fusible ink layer and the transfer control layer is 5 g / m 2 to 12 g / m 2.
Square meters.

The support used in the present invention is a known heat-resistant material, for example, a plastic film such as polyester, polypropylene, polycarbonate, nylon, polyimide, or polystyrene, paraffin paper, or condenser paper. The thickness of the support is preferably about 3 μm to 10 μm from the viewpoint of thermal sensitivity and strength. In addition, a non-stick layer such as a silicone resin, a fluorine resin, a phenol resin, an epoxy resin, a melamine resin, or a polyimide resin is provided as a heat-resistant protective layer on the back surface of the support to improve the heat resistance of the support.

For the hot-melt ink layer used in the present invention, various conventionally known materials are used, and as a coloring material, organic and inorganic pigments or dyes are used.
Preferably, those having a sufficient concentration and excellent in light resistance and the like are used.

The wax component of the hot-melt ink layer includes carnauba wax, candelilla wax, montan wax, wood wax, beeswax, paraffin wax,
Microcrystalline wax, Fischer-Tropsch wax, ester wax, polyethylene wax, lanolin-based wax, various oxidized waxes, and higher fatty acids such as lauric acid and stearic acid are used.

As the heat-meltable resin component of the heat-meltable ink layer, a flexible ethylene-vinyl acetate resin, ethylene-ethyl acrylate resin or the like capable of fixing a colorant and a wax component on a support is used.

[0021]

Next, the present invention will be described in detail with reference to examples. In addition, each component of an Example is set to a weight part or weight%.

Example 1 [Heat-Fusible Ink Composition] Carbon black 15 parts Dispersant 5 parts Paraffin wax 50 parts Carnauba wax 20 parts Ethylene-vinyl acetate resin 10 parts Obtained. [Coating liquid 1] Styrene-maleic acid resin Softening point 135 ° C 10 parts (10% isopropyl alcohol solution) Ethyl cellulose resin 10 parts (10% isopropyl alcohol solution) Silicon modified resin 10 parts (10% isopropyl alcohol solution) Silicon fine particles 3 parts (Average particle diameter: 2 μm, spherical) 50 parts of isopropyl alcohol was stirred to obtain a coating liquid 1. Next, a hot-melt ink is applied by about 6 g / m 2 on a polyester film having a thickness of about 4.5 μm, which is heat-treated on one side, by hot-melt coating to form a hot-melt ink layer. After drying, No. 1 was coated to a thickness of about 0.3 g / m 2 to obtain a thermal transfer recording medium.

Examples 2 and 3 Thermal transfer recording media were obtained in the same manner as in Example 1 except that the average particle diameter of the silicon fine particles of the coating liquid 1 was 0.5 μm and 5 μm, respectively.

Examples 4 and 5 A thermal transfer recording medium was obtained in the same manner as in Example 1, except that the parts by weight of the silicon fine particles of the coating liquid 1 were changed to 1 part and 9 parts, respectively.

Example 6 A thermal transfer recording medium was obtained in the same manner as in Example 1, except that the styrene-maleic acid resin in the coating solution 1 was changed to 0.031 parts, the ethyl cellulose resin was removed, and the silicon-modified resin was changed to 30 parts. .

Example 7 A thermal transfer recording medium was obtained in the same manner as in Example 1 except that the coating liquid 1 was changed to 18.5 parts of styrene-maleic acid resin and 1.5 parts of silicon-modified resin.

Example 8 A thermal transfer recording medium was obtained in the same manner as in Example 1, except that the silicon fine particles of the coating liquid 1 were amorphous silicon dioxide having an average particle diameter of 4 μm.

Comparative Examples 1 and 2 A thermal transfer recording medium was obtained in the same manner as in Example 1, except that the average particle diameter of the silicon fine particles of the coating liquid 1 was 0.3 μm and 6 μm, respectively.

Comparative Example 3 A thermal transfer recording medium was obtained in the same manner as in Example 1, except that the silicon fine particles of the coating liquid 1 were removed.

Comparative Example 4 The parts by weight of the silicon fine particles of the coating liquid 1 in Example 1 were
A thermal transfer recording medium was obtained in the same manner except that the amount was 10 parts.

Comparative Example 5 A thermal transfer recording medium was obtained in the same manner as in Example 1 except that the styrene-maleic acid resin of the coating solution 1 was changed to 20 parts and the silicone resin was removed.

Comparative Example 6 A thermal transfer recording medium was obtained in the same manner as in Example 1 except that the softening point of the styrene-maleic acid resin of the coating solution 1 was changed to 100 ° C.

Comparative Example 7 Silicon fine particles of the coating liquid 1 in Example 1 were used as heat-meltable fine particles (polyethylene wax, average particle diameter 3 μm).
A thermal transfer recording medium was obtained in the same manner except for the above.

The above 15 kinds of thermal transfer recording media were printed 5 times at the same location by a line thermal printer under the following conditions. [Printing conditions] Thermal head: line thin film head (8 dots / mm) Printing speed: 5 inches / sec Printing energy: 18 mj / square millimeter Transfer receiving paper: coated paper (Beck smoothness 300 sec)

Regarding the print density, a Macbeth densitometer TR-
927, the print quality was visually evaluated. The results were as shown in Table 1.

[0036]

[Table 1]

[0037]

As described in the above embodiments, the thermal transfer recording medium of the present invention can provide a high-density and high-quality printed image regardless of the number of times of printing.

Claims (4)

[Claims] 1. A multi-time thermal transfer recording medium in which a heat-fusible ink layer is provided on a support, and a transfer control layer is further provided thereon, in which a transfer control layer has a non-softening property or a high softening point. A transfer control layer forming resin comprising a resin component, a heat-meltable ink and a release resin component for the purpose of having a releasing effect on an image receiving paper, and non-heat-meltable fine particles. Many times thermal transfer recording medium. 2. The non-heat-fusible fine particles have an average particle diameter of 0.5.
μm to 5 μm, and the weight ratio of the non-heat-meltable fine particles to the resin for forming the transfer control layer is 25:75 to 7
5. The multi-time thermal transfer recording medium according to claim 1, wherein the ratio is 5:25. 3. The film-forming resin component has a softening point of 130.
C. or higher, and the release resin component contains one or more of a silicone resin, a silicone-modified resin, and a fluorine-based resin, and the weight ratio of the film-forming resin component to the release resin component is 0. 2. The multi-time thermal transfer recording medium according to claim 1, wherein the ratio is 1: 99.9 to 95: 5. 4. The coating amount of the transfer control layer is 0.05 g.
4. The thermal transfer recording medium according to claim 1, wherein the density of the thermal transfer recording medium is from 1.0 g / m 2 to 1.0 g / m 2.