JPH06286331A - Thermal recording medium - Google Patents

Abstract

PURPOSE:To form a clear picture with lower printing energy in a heat-sensitive transfer recording medium, which is formed by sequentially laminating a base material, an anchor layer, a thin metal film layer and a protecting layer. CONSTITUTION:In a heat-sensitive transfer recording medium, which is formed by sequentially laminating a base material 1, an anchor layer 2, a thin metal film layer 3 and a protecting layer 4, the density of the base material is set at 0.6-1.4g/cm<3>, and the thermal conductivity is set at 1.0 or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording medium capable of forming a clear image on itself by being selectively heated according to image information by a heating means such as a thermal head.

[0002]

2. Description of the Related Art Conventionally, when a sticking label is manufactured by a name printer, a label printer, etc.
As shown in (a), first, release paper 31 and adhesive layer 32
The image receiving paper 32 on which a is laminated and the thermal transfer paper 33 including the base material 33a and the ink layer 33b are overlapped, and the thermal head 34 is used from the base material 33a side of the thermal transfer paper 33 according to the image information to be formed. To heat. In the figure, the shaded portion a is the heating portion. As a result, the ink in the ink layer 33b of the thermal transfer paper 33 is thermally transferred onto the surface of the image receiving paper 32.

Subsequently, as shown in FIG. 3B, the image receiving paper 3
2 and the thermal transfer paper 33 are peeled off.

Further, as shown in FIG.
A label is manufactured by laminating a protective film 36 made of a transparent resin film having excellent abrasion resistance on the ink image 35 formed on the above in order to protect the image. In this case, the steps of FIGS. 3A to 3C are carried out inside one label printer.

The label produced in this way is used as a release paper 3
1 is peeled off, and the pressure-sensitive adhesive layer 32a is pressed to a position to be used, thereby being used.

However, in a conventional label manufacturing system such as a label printer, since the image receiving paper, the thermal transfer paper and the protective film are used as separate members, the number of members is large and the cost cannot be reduced. there were. In addition, the mechanism of the printer required to manufacture one label from such separate members is inevitably complicated, and in addition to the problem that the manufacturing cost of the printer rises, the printer device itself is There was also a problem that there was a limit to miniaturization.

In order to solve this problem, there has been proposed a thermal recording medium in which an image receiving paper, a thermal transfer paper and a protective film are not used as separate members but incorporated in one thermal recording medium. This thermosensitive recording medium basically has the structure shown in FIG.
As shown in (a), it has a structure in which a base material 1, an anchor layer 2, a metal thin film layer 3 and a protective layer 4 are sequentially laminated, and in some cases, between the base material 1 and the anchor layer 2. Colored layer 5
(FIG. 1B) is provided, where the metal thin film layer 3 is provided.
As the material, a vacuum-deposited film of a metal such as tin, nickel-tin alloy, or gold is used.

The principle of recording when heat-sensitive recording is performed on this heat-sensitive recording medium is that the medium is first selectively heated according to image information by a heating means such as a thermal head. As a result, the metal thin film layer 3 is heated to a temperature equal to or higher than the melting point, the heated portion is contracted and destroyed, and an image pattern is formed by the remaining metal thin film layer 3 or the underlying colored layer 5. Therefore, when heat-sensitive recording is performed using such a heat-sensitive recording medium, there is an advantage that an image receiving paper or a thermal transfer paper is not separately required and a protective film is not additionally required.

[0009]

However, in the conventional thermal recording medium shown in FIG. 1, the material forming the metal thin film layer is heated to a temperature above its melting point and contracts and destroys. After the substrate 1 which is the thickest layer in the medium and has the largest heat capacity has been sufficiently heated. Therefore, a large amount of heating energy is required to cause the contraction and destruction of the metal thin film layer. Therefore, the printing energy of about 0.5 mJ / cm ² of the thermal head for the thermal transfer ribbon using the ordinary resin ink is insufficient, and therefore, there is a problem that the ordinary label printer cannot form an image. .

Therefore, a label printer equipped with a dedicated thermal head capable of generating high printing energy of about 1.0 mJ / cm ² or more must be newly manufactured, which increases the cost of image formation. There was a problem. Further, since such a printer cannot be applied to ordinary thermal transfer paper, it has no versatility, and further, a thermal head that realizes such high printing energy has a problem that its reliability is not sufficient.

Therefore, in order to solve these problems,
It has been desired to be able to shrink and destroy the metal thin film layer with lower printing energy.

The present invention is intended to solve the above-mentioned problems of the prior art, including a base material, an anchor layer,
An object of the present invention is to enable a clear image to be formed with lower printing energy in a thermal recording medium in which a metal thin film layer and a protective layer are sequentially laminated.

[0013]

In order to achieve the above-mentioned object, the present inventor makes effective use of the thermal energy consumed by the substrate which is the thickest layer and has the largest heat capacity in the thermal recording medium. It suffices to use it, for that, it is possible to quickly absorb heat energy from a heating means such as a thermal head, but it is difficult to dissipate heat to the outside of the heating part, and it is sufficient to use a material that exhibits excellent heat storage properties. As such a base material, it has been found that a base material having a specific density and thermal conductivity may be used, and the present invention has been completed.

That is, according to the present invention, in a thermal transfer recording medium in which a base material, an anchor layer, a metal thin film layer and a protective layer are sequentially laminated, the density of the base material is 0.6 to 1.4 g / cm ^3.
And a thermal conductivity of 1.0 or less.

The present invention will be described below in detail with reference to the drawings.

The sectional view of the heat-sensitive recording medium of the preferred embodiment of the present invention has the same layer structure as that of the heat-sensitive recording medium shown in FIG. That is, as shown in FIG. 1A, this thermal recording medium has a structure in which a base material 1, an anchor layer 2, a metal thin film layer 3 and a protective layer 4 are sequentially laminated.

The substrate 1 used in the present invention has a density of 0.6 to 1.4 g / cm ³ , preferably 0.1.
A material having a thermal conductivity of 8 to 1.2 and a thermal conductivity of 1.0 or less is used. When the density of the base material 1 is less than 0.6 g / cm ³ , the thermal conductivity is lowered and the thermal sensitivity is lowered, and when it exceeds 1.4 g / cm ³ , the strength of the base material is lowered. Moreover, when the thermal conductivity of the base material 1 exceeds 1.0, the thermal sensitivity is lowered.

As such a substrate 1, it is possible to appropriately select and use various materials having a density and a thermal conductivity within the above-mentioned ranges. For example, a polyethylene terephthalate film, a polypropylene film or the like can be used. Although the thickness of the base material 1 varies depending on the material used, etc., it is generally preferably 9 to 250 μm,
More preferably, it is 12 to 50 μm. When the thickness of the base material 1 is less than this range, the heat storage property and the strength of the base material are deteriorated, and when it exceeds this range, the thermal sensitivity is decreased.

The anchor layer 2 is a layer for improving the adhesiveness of the metal thin film layer 3, and those conventionally used as the anchor layer of the metal thin film layer can be used. For example, nitrocellulose. It is possible to use a blend polymer of acrylic resin and acrylic resin. The thickness of the anchor layer 2 is not particularly limited, but generally 0.5 to 4
μm, preferably 1 to 2 μm.

The metal thin film layer 3 is a layer in which a heated portion is contracted and destroyed by being selectively heated according to image information, and the remaining metal thin film layer 3 forms an image pattern. As such a metal thin film layer, a vapor deposition film of tin, nickel-tin alloy, gold or the like can be used. The thickness of the metal thin film layer is not particularly limited as long as it can sufficiently reflect light, for example, about 500.
A thickness of ~ 800 Å is preferred.

The protective layer 4 is a layer for preventing the metal thin film layer 3 from being directly contacted with other objects and damaged.
A light-transmitting thermoplastic resin which has been conventionally used can be used. Such thermoplastic resins include polyester resins and vinyl chloride / vinyl acetate /
Acrylic ester copolymers and the like can be used. The thickness of the protective layer 4 is not particularly limited, but is generally 1.0 to 3.0 μm, preferably 2 to 3 μm in consideration of abrasion resistance and the like.

On the surface of the base material 1 opposite to the anchor layer 2,
A general pressure-sensitive adhesive layer may be provided, and in that case, it is preferable to further cover the pressure-sensitive adhesive layer with release paper.

Another aspect of the present invention is shown in FIG.
A layer structure similar to that of the heat-sensitive recording medium (b) can be employed. In the embodiment shown in this figure, the coloring layer 5 is formed between the base material 1 and the anchor layer 2. When such a colored layer 5 is formed, the colored layer 5 becomes visible when the metal thin film layer 3 is shrunk and destroyed by heating, and the image expression can be diversified. The colored layer 5 is not particularly limited, and various pigments or dyes dispersed in a vanider can be appropriately selected and used.

Although not shown, a surface coloring layer may be provided between the protective layer 4 and the metal thin film layer 3. As a result, the image expression can be further diversified. Further, such a surface coloring layer is not particularly limited, and various pigments or dyes dispersed in a binder can be appropriately selected and used.

The heat-sensitive recording medium of the present invention can be manufactured by a conventional method. For example, the base layer 1 is coated with the composition for forming an anchor layer and dried to form the anchor layer 2, which is further deposited in a vapor deposition chamber. It can be manufactured by depositing tin or the like to form the metal thin film layer 3 and then coating the resin composition for forming a protective layer thereon to form the protective layer 4.

The heat-sensitive recording medium of the present invention can be preferably applied to a recording apparatus using a general thermal head as a heating means for recording, but the heating means can be applied to a recording apparatus using infrared rays or laser light. Can also be applied.

[0027]

In the thermosensitive recording medium of the present invention, since the base material having a density of 0.6 to 1.4 g / cm ³ and a thermal conductivity of 1.0 or less is used, the thermosensitive recording medium is heated. In this case, the base material can quickly absorb heat and sufficiently store heat, so that the metal thin film layer can be heated with high efficiency. Therefore, it is possible to form a clear image with lower printing energy.

[0028]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 Thickness 38 with a density of 1.4 g / cm ² and a thermal conductivity of 0.9
Using a polyethylene terephthalate film (manufactured by Diafoil Co., Ltd.) of μm as a base material,
Nitrocellulose acrylic resin (VM-AL, manufactured by Dainichiseika Co., Ltd.) was replaced with methyl ethyl ketone / toluene (7 /
An anchor layer was formed by applying a composition obtained by adding 3% (based on resin) of an isocyanate curing agent to a solution (30% by weight) dissolved in the mixed solvent of 1) so that the dry thickness would be 2 μm.

6 is formed on the anchor layer by a vacuum deposition method.
A tin vapor deposition layer having a thickness of 00 angstrom was formed.

Further, on this metal thin film layer, vinyl chloride /
A solution (10% by weight) of a vinyl acetate / acrylic acid ester copolymer (manufactured by Union Carbide Co., Ltd.) dissolved in a mixed solvent of methyl ethyl ketone / toluene (7/1) was applied to a dry thickness of 2 μm. A thermosensitive recording medium was obtained by forming a protective layer.

A solid image was formed on this thermal recording medium, and the relationship between the printing energy and the reflection density of the image was examined. The result is shown in FIG. From the figure, 1.0mJ / cm
^With a printing energy as low as ^2, a practically sufficient image density (1.8) could be achieved.

Example 2 As a substrate, the density was 1.1 g / cm ² and the thermal conductivity was 0.
A thermal recording medium was manufactured in the same manner as in Example 1 except that a 38 μm thick polyethylene terephthalate film (manufactured by Diafoil Co., Ltd. 9) was used, and the relationship between the printing energy and the reflection density of the image was examined. The result is shown in Figure 2.
Shown in. From the figure, it was possible to achieve a practically sufficient image density (1.9) with a printing energy as low as 0.8 mJ / cm ² .

Example 3 A substrate having a density of 0.9 g / cm ² and a thermal conductivity of 0.
A thermal recording medium was manufactured in the same manner as in Example 1 except that 38-μm-thick polypropylene synthetic paper (manufactured by Diafoil Co., Ltd. 9) was used, and the relationship between the printing energy and the reflection density of the image was examined. . The result is shown in FIG. From the figure, it was possible to achieve a practically sufficient image density (1.8) with a printing energy as low as 0.7 mJ / cm ² .

[0035]

According to the thermosensitive recording medium of the present invention, a clear image can be formed with low printing energy.

[Brief description of drawings]

FIG. 1 is a sectional view of a thermal recording medium.

FIG. 2 is a diagram showing the relationship between the printing energy of the thermosensitive recording medium of the present invention and the image density of an image.

FIG. 3 is a process explanatory diagram of a conventional thermal recording method.

[Explanation of symbols]

 1 Base Material 2 Anchor Layer 3 Metal Thin Film Layer 4 Protective Layer 5 Colored Layer

Claims (2)

[Claims] 1. A heat-sensitive recording medium comprising a base material, an anchor layer, a metal thin film layer and a protective layer, which are sequentially laminated, and has a base material density of 0.6 to 1.4 g / cm ³ and a thermal conductivity of 1. ．
A thermal recording medium characterized by being 0 or less. 2. The thermosensitive recording medium according to claim 1, wherein the substrate has a thickness of 9 to 250 μm.