JP2922734B2 - Thermal transfer recording medium - Google Patents

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, and more particularly to a thermal transfer recording medium capable of realizing clear two-color recording.

[0002]

2. Description of the Related Art A thermal transfer recording system uses a thermal transfer recording medium obtained by applying at least one layer of a thermal transferable ink on a base material on a sheet. This is a recording method in which an ink layer is heated and melted by a heating head from the substrate side of a thermal transfer recording medium to obtain a transfer image on a transfer paper, in such a manner as to be in contact with the substrate. According to this method, a device to be used is low noise, excellent in operability and maintainability, and plain paper can be used as a paper to be transferred.

[0003] In recent years, in the thermal transfer recording system, there has been a strong demand for multicolor or full-color recording. In order to achieve this multicoloring, a difference is provided between the melting points of the inks between the layers (Japanese Patent Application Laid-Open Nos.
Japanese Patent Application Laid-Open No. 2-183388, Japanese Patent Application Laid-Open No. 62-183388), providing a difference in the melt viscosity of ink between layers (Japanese Patent Application Laid-Open No. 62-68791), and providing a separation layer between ink layers (Japanese Patent Application Laid-Open JP-A-56-14859, JP-A-62-1984
183391), and the use of a supercooling inducer (Japanese Patent Laid-Open No. 2-299875).

[0004]

However, even with the above technique, for example, in the case of two-color recording, it is difficult to selectively transfer only the upper layer, or the transfer of the lower layer is incomplete. Therefore, it has been difficult to realize clear two-color recording printing in both the upper layer and the lower layer. Accordingly, an object of the present invention is to provide a thermal transfer recording medium capable of printing clear two-color recordings.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a conventional release layer is provided by providing a release layer mainly composed of wax between the base material and the first thermal transfer ink layer. The function of the first thermal transfer ink layer, which could not be achieved by the type without the ink, was binarized with respect to the applied energy (transfer was not performed at a low applied energy, and complete transfer was performed at a high applied energy). By imparting complete transferability with high applied energy to the second thermal transfer ink layer to the second thermal transfer ink layer), it was confirmed that the present invention was completed.

That is, according to the present invention, a wax is mainly contained on a substrate, and an ethylene-vinyl acetate copolymer is contained.
A release layer melt viscosity of 10~500cSt at ° C., a layer of the first thermal transfer ink and a layer of the second thermal transfer ink having a different color tone with the first thermal transfer ink, Ri Na provided in this order And the second thermal transferable ink layer at 120 ° C.
Melt viscosity at 120 ° C. of the first thermal transfer ink layer
An object of the present invention is to provide a thermal transfer recording medium characterized by having a higher melt viscosity .

[0007] The melt viscosity at 100 ° C. of the release layer of wax mainly used in the present invention is 10 ~500c St.
If the melt viscosity at 100 ° C. of the release layer is less than 10 cSt, the coating on the rough surface paper is poor, and if it exceeds 500 cSt, the transfer of the second thermal transfer ink layer is poor.

The wax used in the release layer is preferably one or more selected from the group consisting of microcrystalline wax, carnauba wax, candelilla wax, rice bran wax, and oxidized polyethylene wax. In addition to the waxes, resins such as an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid copolymer, polyethylene, and a petroleum resin may be added to improve the strength of the coating film. The thickness of the release layer mainly composed of wax is not particularly limited, but is generally about 0.5 to 2.0 μm.

As the coloring component of the first and second heat transferable ink layers used in the present invention, any colorant having coloring ability can be used, and a color tone different from the color tone selected for the first heat transferable ink layer. Is selected as the second heat transferable ink layer. As coloring components, for example, dyes and pigments such as carbon black, oil black, graphite, and CI PigmentYel
low 1,3,74,97,98 acetoacetate arylamide monoazo yellow pigment (fast yellow), CIPi
gment Yellow 12, 13 and 14 acetoacetic acid arylamide-based bisazo yellow dyes, CI Pigment Yellow 19 and 7
7, 79, yellow pigments such as CI Disperse Yellow 164, CI
Pigment Red 48, 49: 1, 53: 1, 57: 1, 8
1, 122, 5 and other red or red pigments, CISolvent R
Red pigments such as ed52, 58, and 8; CI Pigment Blue 15
: Blue dyes and pigments such as copper phthalocyanine and its derivatives and denatured products such as 3; Further, dyes and pigments known in the related art for printing inks and other coloring purposes, such as colored or colorless sublimable dyes, can be used. The amount is not particularly limited, but is optimally 10 to 60% by weight in the paint for forming the ink layer.

These dyes and pigments may be used alone or as a mixture of two or more kinds. However, in the thermal transfer recording medium of the present invention, a color tone different from the color tone selected for the first thermal transfer ink layer for multicoloring is used. 2 Select the thermal transfer ink layer. Especially the first
It is desirable to use a dark color dye for the thermal transfer ink layer and a light color dye for the second thermal transfer ink layer.

Further, as the ink binder of the first and second thermal transfer ink layers used in the present invention, a known wax or a thermoplastic resin conventionally used as a binder of the thermal transfer ink can be used as it is. .
For example, beeswax, carnauba wax, wood wax, candelilla wax, paraffin wax, microcrystalline wax, natural waxes such as ester wax,
Synthetic waxes such as polyethylene wax, oxidized polyethylene wax, acid wax, stearic acid, behenic acid,
Higher fatty acids such as montanic acid, higher fatty acid esters such as behenic acid monoglyceride, sorbitan stearate ester and pentaerythritol stearate, higher fatty acid amides such as stearic acid amide, oleic acid amide and behenic acid amide, and petroleum resins; Ethylene-
Acrylic acid copolymers and acrylic resins are used alone or in combination of two or more.

Further, the melt viscosity at 120 ° C. of the second heat transferable ink layer used in the present invention is desirably higher than that of the first heat transferable ink layer .

The thicknesses of the first thermal transfer ink layer and the second thermal transfer ink layer are not particularly limited.
m is common.

As the base material of the thermal transfer recording medium of the present invention,
Paper sheets such as condenser paper and glassine paper, thin sheets and films of polyester such as polyethylene terephthalate, and plastics such as polyimide, polycarbonate, polyamide, polyethylene, and polypropylene are used. The thickness of the substrate is preferably in the range of 2 to 20 μm.
Further, in order to improve heat resistance and running properties, a silicone-based or fluorine-based compound, a resin layer, a crosslinked polymer layer, a metal layer, or the like may be provided on the side of the substrate that comes into contact with the thermal head.

[0015]

According to the present invention, there is provided a thermal transfer recording medium capable of performing clear two-color recording in one printing operation.

[0016]

EXAMPLES The present invention will be described below with reference to examples, but it is needless to say that the present invention is not limited to these examples. In the examples, “%” is based on weight unless otherwise specified.

Example 1 Rice bran wax is blended in toluene at a composition ratio shown in column A of the blending table 1 so as to have a solid concentration of 10%. This is dispersed using a ball mill for 12 hours to form a paint. Using a wire bar coater, this paint was applied on a 3.5 μm thick PET film treated with a silicon back coat to a dry weight of 0.7 g / m ² .
Form a wax release layer.

Next, it is blended in toluene at a composition ratio shown in column D of the blending table 2 so that the solid content concentration becomes 10%. This is dispersed using a ball mill for 12 hours to form a paint. This paint is applied using a wire bar coater to a dry weight of 2.5 g / m ² on the wax release layer side of the PET film to which the wax release layer has been applied, to form a first ink layer.

Finally, it is blended in toluene at a composition ratio shown in the column G of the blending table 3 so that the solid content concentration becomes 10%. This is dispersed using a ball mill for 12 hours to form a paint. This paint was applied to the wax release layer side of the PET film coated with the wax release layer using a wire bar coater to a dry weight of 3 g / m ² to form a second ink layer. Slit to obtain thermal transfer ink ribbon.

Using this ribbon, commercially available NEC Corporation
When printing was performed with a personal word processor Bungo Mini 5HG (20 characters / second), the results shown in Table 4 were obtained.

Example 2 Carnauba wax is blended in toluene at a composition ratio shown in column B of the blending table 1 so that the solid content concentration becomes 10%. This is dispersed using a ball mill for 12 hours to form a paint. This paint was treated with a silicon-based back coat using a wire bar coater.
The composition is applied on the film to a dry weight of 0.7 g / m ² to form a wax release layer.

Next, it is blended in toluene so that the solid content concentration becomes 10% at the composition ratio shown in the column E of the blending table 2. This is dispersed using a ball mill for 12 hours to form a paint. This paint is applied using a wire bar coater to a dry weight of 2.5 g / m ² on the wax release layer side of the PET film to which the wax release layer has been applied, to form a first ink layer.

Finally, it is blended in toluene so as to have a solid concentration of 10% at the composition ratio shown in the column H of the blending table 3. This is dispersed using a ball mill for 12 hours to form a paint. This paint was applied to the wax release layer side of the PET film coated with the wax release layer using a wire bar coater to a dry weight of 3 g / m ² to form a second ink layer. Slit to obtain thermal transfer ink ribbon.

Using this ribbon, printing was carried out with a commercially available personal word processor Bungo Mini 5HG (20 characters / second) manufactured by NEC, and the results shown in Table 4 were obtained.

Example 3 Using microcrystalline wax, it is blended in toluene at a composition ratio shown in the column C of the blending table 1 so that the solid content concentration becomes 10%. This is dispersed using a ball mill for 12 hours to form a paint. This paint was treated with a silicon-based back coat using a wire bar coater to a thickness of 3.5
The composition is applied on a PET film of μm so as to have a dry weight of 0.7 g / m ² to form a wax release layer.

Next, it is blended in toluene so as to have a solid content concentration of 10% at the composition ratio shown in the column F of the blending table 2. This is dispersed using a ball mill for 12 hours to form a paint. This paint is applied using a wire bar coater to a dry weight of 2.5 g / m ² on the wax release layer side of the PET film to which the wax release layer has been applied, to form a first ink layer.

Finally, it is blended in toluene at a composition ratio shown in column I of the blending table 3 so that the solid content concentration becomes 10%. This is dispersed using a ball mill for 12 hours to form a paint. This paint was applied to the wax release layer side of the PET film coated with the wax release layer using a wire bar coater to a dry weight of 3 g / m ² to form a second ink layer. Slit to obtain thermal transfer ink ribbon.

Using this ribbon, printing was performed with a commercially available personal word processor Bungo Mini 5HG (20 characters / second) manufactured by NEC, and the results shown in Table 4 were obtained.

COMPARATIVE EXAMPLE 1 At the composition ratio shown in the column D of the formulation table 2, it is blended in toluene so as to have a solid concentration of 10%. This is dispersed using a ball mill for 12 hours to form a paint. Using a wire bar coater, this paint was dried on a 3.5 μm thick PET film treated with a silicon back coat.
It is applied so as to be 2.5 g / m ² to form a first ink layer.

Next, it is blended in toluene at a composition ratio shown in the column I of the blending table 3 so that the solid content concentration becomes 10%. This is dispersed using a ball mill for 12 hours to form a paint. The coating using a wire bar coater, first i
A second ink layer is formed on the PET film to which the ink layer has been applied so as to have a dry weight of 3 g / m ² on the side of the wax release layer to form a second ink layer, and slit to a predetermined width to obtain a thermal transfer ink ribbon.

Using this ribbon, printing was carried out with a commercially available personal word processor Bungo Mini 5HG (20 characters / second) manufactured by NEC, and the results shown in Table 4 were obtained.

COMPARATIVE EXAMPLE 2 Compounds were blended in toluene so that the solid content concentration was 10% at the composition ratio shown in column E of formulation table 2. This is dispersed using a ball mill for 12 hours to form a paint. Using a wire bar coater, this paint was dried on a 3.5 μm thick PET film treated with a silicon back coat.
It is applied so as to be 2.5 g / m ² to form a first ink layer.

Next, it is blended in toluene at a composition ratio shown in the column G of the blending table 3 so that the solid content concentration becomes 10%. This is dispersed using a ball mill for 12 hours to form a paint. The coating using a wire bar coater, first i
A second ink layer is formed on the PET film to which the ink layer has been applied so as to have a dry weight of 3 g / m ² on the side of the wax release layer to form a second ink layer, and slit to a predetermined width to obtain a thermal transfer ink ribbon.

Using this ribbon, printing was carried out with a commercially available personal word processor Bungo Mini 5HG (20 characters / second) manufactured by NEC, and the results shown in Table 4 were obtained.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

[Table 4]

Here, the symbols for sharpness in Table 4 are as follows: ○: No color mixture is observed in two-color printing. Δ: Some color mixture is observed. ×: considerable color mixture is observed. Or, the printing quality of characters is poor. Means The print density is a value obtained by measuring the reflection density of a solid printing portion using a Macbeth reflection densitometer.

As shown in Table 4, the two-color thermal transfer recording medium of the present invention provides clear and high-resolution printing in both the printing with the first ink layer and the printing with the second ink layer. It turns out that the purpose of the invention is sufficiently fulfilled.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B41M 5/40

Claims (1)

(57) [Claims] Claims: 1. A wax-based material on a substrate ,
Melt viscosity at 100 ° C containing vinyl-vinyl acetate copolymer
And degree peeling layer 10～500CSt, a layer of the first thermal transfer ink and a layer of the second thermal transfer ink having a different color tone with the first thermal transfer ink, Ri Na provided in this order, and the
The melt viscosity at 120 ° C. of the second heat transferable ink layer is
Than the melt viscosity of the first thermal transfer ink layer at 120 ° C
A thermal transfer recording medium characterized by being expensive .