JP2541187B2 - Ink ribbon for thermal melting transfer - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ink ribbon for thermal melting transfer used in thermal transfer recording.

[Outline of Invention]

The present invention provides an ink ribbon for thermal melting transfer, which comprises a base material, an ink layer formed on the base material, and further, which is formed on the ink layer, melts at the time of thermal transfer, and By forming the transparent surface layer having a viscosity smaller than that of the ink layer, it is possible to print favorably even on rough paper.

[Conventional technology]

In the conventional thermal melt transfer ink ribbon, a colorant-containing ink layer is formed on a substrate made of polyethylene terephthalate, or a release layer is further formed between the substrate and the ink layer. It is composed by.
When thermal transfer recording is performed using this ink ribbon, printing is performed by causing the ink layer melted by the heat of the heat-sensitive head to flow onto the opposite paper surface for transfer.

[Problems to be solved by the invention]

In the case of heat-sensitive transfer recording using an ink ribbon for heat-melt transfer, the smoother the surface of the paper, the more uniformly the ink is transferred, so that high-quality printing can be obtained. Therefore, on the contrary, when the paper surface is rough, especially in the case of rough paper having a smoothness of 30 seconds or less, the melted ink adheres only to the convex portion of the surface of the paper, and the ink does not flow into the concave portion. Only a printed material having a large number of voids (inks) in which the ink to be transferred remains on the ink ribbon can be obtained.

In order to solve such a problem, for example, the viscosity of the ink is lowered or the temperature and pressure of the thermal head are increased so that the ink is sufficiently transferred to the concave portion of the rough surface of the conventional paper. I took the method of. However, as shown in FIG. 10, when the printing energy and pressure applied to the thermal head (2) are increased, if the paper (1) is smooth paper, the ink will squeeze out from a place other than the place where the printing should be performed. ) Becomes thicker and loses sharpness, and conversely, at the center of the print (6), the ink becomes thinner and the density decreases. In Figure 10,
(3) is a base material, (4) is an ink layer, and (5) is an ink ribbon. Also, in the case of rough paper (1), as shown in FIG. 11, the ink spreads laterally to cause transfer of the ink to places other than where it should be printed, and many voids (7) are also created, resulting in clear printing. (6) was never obtained.

As shown in FIG. 12, in order to make the transfer of the ink to the rough paper (1) uniform, an ink ribbon (a release layer (8) is provided between the ink layer (4) and the substrate (3) ( It has been proposed to use 5) to transfer the ink layer (4) onto the paper (1) surface. However, this method has the drawback that the optimum range of transfer conditions becomes very narrow, and the ink is not sufficiently transferred onto the paper (1) surface during high-speed printing. Further, in order to improve the ink running-out by using such an ink ribbon (5), the peeling angle of the ink ribbon (5) needs to be sharp and a specially designed heat sensitive head is required. There is a point.

The present invention provides an ink ribbon for hot melt transfer capable of solving the above problems.

[Means for solving problems]

In the present invention, an ink layer (12) is formed on a substrate (11), and a transparent surface layer (transferred surface) having a viscosity smaller than that of the ink layer (12) at the time of thermal transfer is formed on the ink layer (12). An ink ribbon (14) for thermal transfer is formed by forming an anchor layer (13) for the ink. At this time, the viscosity of the ink layer (12) at 100 ° C was selected to be 2500cps to 100000cps, and the viscosity of the surface layer (13) at 100 ° C was 100cps to 200cps.
Select 0cps.

The material of the base material (11) can be selected from heat resistant resins typified by polyimide, polyester, polyarylate, triacetyl cellulose, nylon, polycarbonate, polyamide imide, and paper. In addition, even if the material does not have such heat resistance, the thickness of the base material (11) made of silicone resin, epoxy resin, melamine resin, phenol resin, fluorine resin, polyimide resin, nitrocellulose, cellulose acetate, etc. If a heat-resistant protective layer (18) having a thickness of about 0.5 to 2 μ is provided, it can be used.

The ink layer (12) is an ethylene-vinyl acetate copolymer,
A mixture of this with wax, a mixture of low melting point resins, polyvinyl ether, polyamide, etc., carbon black,
The composition comprises a colorant such as a dye or an organic pigment and, if necessary, various fillers (clay, silica, talc, etc.), oils, fatty acid salts, and other additives. The melt viscosity of the ink layer (12) at a normal thermal transfer temperature of 100 ° C. is 2,500 to 100,000 cps. If it is less than 2,500 cps, the ink may flow in the lateral direction during thermal fusion transfer, or the paper may be soaked and bleeding so that clean printing cannot be obtained. If it exceeds 100,000 cps, the ink layer will not be cut well and is not suitable for high-speed printing. Although the thickness of the ink layer (12) is not particularly limited, it is preferably about 2 to 5 μm, and is 6 to 7 μ at most. If it is too thick, heat conduction will be insufficient and the surface layer will not be sufficiently melted.

The ink ribbon (14) according to the present invention may include a release layer (17) between the base material (11) and the ink layer (12) if necessary.
May be formed. As the material of this release layer (17),
Ethylene-vinyl acetate copolymer, a mixture of wax and wax, a mixture of low melting point resins, vinyl acetate, polyamide, ketone resins, etc., which soften and melt at 65 ° C. or higher, and the cohesive force sharply decreases, or the base material It is preferable to use a material whose adhesion to (11) decreases. The thickness of this release layer (17) is preferably 0.
Approximately 5 to 1 μ.

As the material of the surface layer (13), any of the resin examples used in the ink layer (12) and the release layer (17) can be used as long as it has the following predetermined viscosity.
The melt viscosity of this surface layer (13) at 100 ° C is 100 to 2,000.
Set to 0 cps. When it is less than 100 cps, the cohesive force of the surface layer (13) is too low to prevent the ink layer (12) from being transferred to the paper (15) side together with the surface layer (13). In the case of 2,000 cps, the surface layer (13) becomes difficult to flow on the paper surface, so that the effect that the surface layer (13) fills the rough surface of the paper (15) cannot be obtained. The thickness of this surface layer (13) is not particularly limited,
2μ. The surface layer (13) is made transparent without adding a coloring pigment or the like, particularly when it also serves to prevent scumming.

[Action]

As shown in FIG. 6, the melt viscosity of the surface layer (13) formed on the ink layer (12) of the present ink ribbon (14) at the time of thermal transfer (for example, 100 ° C.) is different from that of the ink layer (12). . In the drawing, the shaded area indicated by F is the ink layer (12), and the shaded area indicated by G is the surface layer (13). Therefore, the ink layer (12) itself has a small amount of lateral flow of ink at a normal melting temperature, but has a weak adhesive force to paper. High-speed printing is impossible because it requires a fairly high temperature and narrows the optimum condition range in order to increase the adhesive strength and obtain clean printing. On the other hand, the ink layer (12) according to the present invention
The surface layer (13) formed above melts and adheres to the convex portion of the rough surface during thermal transfer, and also flows into the concave portion depending on the temperature to sufficiently adhere the ink and the paper (15), and at the same time the high viscosity ink layer. Since it has a function of peeling (12) from the base material (11), clear printing can be achieved.

Therefore, the peeling of the ink ribbon (14) becomes easier, and it becomes unnecessary to peel the ink ribbon (14) at an acute angle and to control the printing conditions within a narrow temperature and pressure range.

Generally, the heat of the heat-sensitive head is not sufficiently transmitted to the paper surface side in the thickness direction of the ink layer (12), so that the high viscosity ink layer on the paper surface side is not sufficiently melted and is difficult to be transferred. Also,
This becomes remarkable as the printing speed increases. However, according to the present invention, since the surface layer (13), which is a low temperature melting layer, is formed in the vicinity of the lowest temperature due to the thermal head in the ink layer (12), the surface layer (13) has a rough surface. Even on paper, the ink transfer is complete, and since the ink itself has a high viscosity, it does not flow in the lateral direction, enabling clear printing at high speed on both smooth and rough paper. it can.

〔Example〕

Example 1 As shown in FIG. 1, an ink liquid A having the following composition was applied to one side of a substrate (11) made of polyethylene terephthalate (PET) having a thickness of 4 μ to form an ink layer (1
After forming 2), a solution A having the following composition is applied onto the ink layer (12) to form a surface layer (13) having a thickness of 2 μ, and the ink ribbon for thermal melting transfer according to the present embodiment. (14)
Is prepared.

This ink ribbon (14) was used to print at a thermal head applied energy of 0.7 W and a printing speed of 40 cps (Character Per Second). Even with 15), there are almost no voids, so-called background stains on the non-printed part (the ink layer (12) rubs against the rough surface of the rough paper, and the peeling transfer of the ink layer (12) to the non-printed part Clear print (16) was obtained. Further, as shown in FIG. 3, on the smooth paper (15), there was little ink flow, and clear print (16) with high density was obtained.

Example 2 As shown in FIG. 4, a base material (1
Apply solution B having the following composition on one side of 1) to a thickness of 0.5
After forming the release layer (17) having a thickness of .mu., the ink liquid B having the following composition is applied to form an ink layer (12) having a thickness of 4 .mu.m. Next, a solution C having the following composition is applied onto the ink layer (12) to form a surface layer (13) having a thickness of 1.5 μm, thereby forming a thermal melting transfer ink ribbon ( 14) is prepared.

When this ink ribbon (14) was used to print with thermal head applied energy of 0.7 W and printing speed of 40 cps,
Bond paper with a smoothness of 10 seconds as shown in Fig. 2 (15)
In the case of, a clear print (16) was obtained with a slight void. Further, as shown in FIG. 3, in the case of the smooth paper (15), clear printing (16) without ink flow was obtained.
When printing was carried out under the same conditions, a print body having substantially the same thickness and density of the font was obtained on both the smooth paper and the bond paper. The print quality could be further improved by setting the peeling angle of the ink ribbon (14) to an acute angle.

Comparative Example 1 As shown in FIG. 8, a base material (1
An ink liquid D having the following composition is applied to one surface of 1) to form an ink layer (12) having a thickness of 5 μm, whereby a thermal melting transfer ink ribbon (19) according to this comparative example is produced.

Using this ink ribbon (19), printing was performed under the same conditions as in the above example. When rough paper with a smoothness of 10 seconds or less was found, the ink layer (12) was rubbed significantly and scumming. Bleeding due to soaking and numerous voids were generated, resulting in poor quality printing with unclear contours. At the time of transfer, since the cohesive force of the ink was too low, the ink layer was transferred while being destroyed. In addition, the thickness of the ink became non-uniform due to the ink soaking into the paper and the lateral seeping out, resulting in a marked decrease in the density. On the other hand, in the case of a smooth paper having a smoothness of 100 seconds, high-quality printing was obtained, but the ink flowed in the lateral direction, resulting in a very thick printed material.

Comparative Example 2 As shown in FIG. 9, a base material (1
The same solution B as in Example 2 was applied to one surface of 1) to a thickness of 2 μm.
Forming a release layer (17). Next, the ink B is applied onto the release layer (17) to form an ink layer (12) having a thickness of 4 μm, thereby manufacturing the thermal melting transfer ink ribbon (19) according to this comparative example. To do.

Using this ink ribbon (19), printing was carried out under the same conditions as in the above example. In the case of rough paper with a smoothness of 10 seconds or less, the ink thickness was uniform, but the ink layer (1
Since the transfer of 2) was incomplete, voids were generated everywhere, resulting in poor quality printing. However, when the ink ribbon (19) was immediately peeled off at an acute angle of 50 ° or more after printing, the printing quality was considerably improved. On the other hand, in the case of paper having a smoothness of 100 seconds, a slight amount of ink flowed in the lateral direction, and the printed material became slightly thick.

FIG. 7 shows a graph in which the relationship between the printing speed and the reflection density of printing was measured for the above-mentioned Examples and Comparative Examples. The paper used was a bond paper with a smoothness of 4 seconds, and the applied energy was 0.7 W × 1 msec. In the drawings, a curve A is Example 1, a curve B is Example 2, a curve C is Comparative Example 1, and a curve D.
Shows Comparative Example 2, respectively. From this graph, the ink ribbon (14) according to the present embodiment is the ink ribbon (1) of the comparative example.
Compared with 9), it can be seen that high-density printing can be obtained even if the printing speed is increased, and accordingly, high-speed printing can be supported.

In each of the examples described above, nothing is formed on the surface of the base material (11) on which the ink layer (12) is not formed, but as shown in FIG. 5, the ink layer (12) of the base material (11) is used. Alternatively, the heat-resistant protective layer (18) may be formed on one surface on which the heat-resistant protective layer (18) is not formed.

〔The invention's effect〕

According to the present invention, since a transparent surface layer that is melted at the time of thermal transfer on the ink layer and has a viscosity smaller than that of the ink layer at the time of melting is formed, a rough paper having a smoothness of 30 seconds or less can be obtained. However, voids due to insufficient transfer of ink are scarcely generated, and it is possible to print a high-density and clear print medium under a wide range of conditions. Further, it is possible to obtain a printed material of substantially the same quality under the same conditions regardless of whether it is smooth paper or rough paper, and thus it is possible to cope with high speed printing.

[Brief description of drawings]

1, 4, and 5 are cross-sectional views of the embodiment, FIGS. 2 and 3 are cross-sectional views showing a printing state, and FIG. 6 is a temperature of an ink layer and a surface layer constituting the present ink ribbon. FIG. 7 is a graph for measuring the reflection density of printing with respect to the printing speed for the ink ribbons of the example and the comparative example, FIG. 8 and FIG. 9 are sectional views of the comparative example, and FIG.
FIG. 12 is a sectional view of a conventional example. (11) is a base material, (12) is an ink layer, (13) is a surface layer,
(14) and (19) are thermal melt transfer ink ribbons, (15) is paper, (16) is printing, (17) is a release layer, and (18) is a heat-resistant protective layer.

Front page continuation (72) Inventor Takeshi Sagara 18 Satsukicho, Kanuma City, Sony Chemical Co., Ltd. Kanuma Plant (56) References JP-A-60-145891 (JP, A) JP-A-60-115488 (JP, A) ) JP-A 59-114098 (JP, A) JP-A 60-189493 (JP, A) JP-A 61-44661 (JP, A) JP-A 61-77270 (JP, A)

Claims (1)

(57) [Claims] 1. A thermal transfer ink ribbon comprising a heat-meltable ink layer and a transparent surface layer having a smaller melt viscosity than that of the heat-meltable ink layer, which are successively laminated on one surface of a substrate, the melted ink ribbon comprising: Viscosity of the water-soluble ink layer at 100 ℃ is 2500cps ~
An ink ribbon for thermal fusion transfer, wherein the surface layer has a melt viscosity at 100 ° C. of 100 cps to 2000 cps.