JPS61290079A - Color thermal transfer ribbon - Google Patents

Abstract

PURPOSE:To enable an end detection part of a color thermal transfer ribbon to be detected by an optical sensor without causing malfunctions under the effect of external illuminating light or solar rays, by a construction wherein a back layer formed of a dispersed mixture of an opaque powder with a resin binder non-adhesive to a thermal head is provided on a substantially entire area of the back side of a base expect an end detection part. CONSTITUTION:The color thermal transfer ribbon 1 comprises a transparent end detection part 2 at its trailing end part devoid of an ink layer or a back layer. The base of the ribbon is a plastic film. The back layer 4 formed of a dispersed mixture of a binder and an opaque powder is provided on the back side of the base except the end detection part 2. A thermal transfer ink layer 3 may be of the head fusion transfer type or the thermal sublimation transfer type, and comprises a known pigment or dye as a coloring agent. Accordingly, the difference in light transmittance between the part provided with the ink layer and the end detection part can be securely detected by the optical sensor with such a sensitivity as to ensure an operation free of external effects, thereby sticking between the thermal head and the base can be obviated.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a color thermal transfer ribbon used in printing devices such as typewriters and computer printers. selectively transferring a thermal transfer ink layer of a color other than black provided on the surface of the support to a recording paper by heating;
It is used to form a print image of a color other than black on recording paper, and when it reaches the end, an optical sensor installed in the printing device detects the end. A thermal transfer ink layer of colors other than black is provided,
The present invention relates to a color thermal transfer ribbon in which a transparent end detection portion is provided at the end of the support.

[Prior art and its problems] In a conventional printing device, a transparent end detection part is provided at the end of a thermal transfer ribbon to change the light transmittance between the part where the thermal transfer ink layer is present and the end detection part. An optical sensor installed in the printing device detects this change in light transmittance, detects the end of the ribbon, and stops the recording operation.

On the other hand, in order to meet the demand for recorded images in colors other than black, such as yellow, cyan, or magenta, color thermal transfer ribbons with thermal transfer ink layers in colors other than black as described above have been manufactured, and When the printer started printing, a problem arose in that the end of the ribbon was not detected and the image forming operation continued even though the ribbon was broken.

As a result of various studies, the reason for this problem is that ink layers of colors other than black transmit light more easily than black (i.e., there is less variation in light transmittance between the transparent end detection area and the ink layer existing area). It turned out that this was due to the inability of the optical sensor to detect the fluctuation.

For this reason, we attempted to improve the sensitivity of the optical sensor, but this resulted in malfunctions due to the influence of external lighting and sunlight.

[Means for Solving the Problem] In view of the above circumstances, the present invention includes dispersing and mixing opaque powder in a resin binder that does not adhere to the thermal head over almost the entire back surface of the support except for the end detection portion. A structure in which a back layer is provided is adopted.

[Operation and Effect] With the above configuration, the location where the ink layer is provided can be made opaque without any change in the color of the ink layer, and the optical sensor can detect the difference in light transmittance with the end detection section. We were able to make it sensitive enough to operate without external influences and to ensure reliable detection.

Furthermore, the opaque powder can sufficiently withstand direct heating by the thermal head, and the stick phenomenon that occurs when the thermal head adheres to the support is combined with the action of the binder to fix the opaque powder to the support. I was able to eliminate it.

[Example] Next, the present invention will be explained in detail.

In FIG. 1, (1) is a color thermal transfer ribbon,
A transparent end detection portion ('2J) is provided at the end without an ink layer or back layer.

The support for the ribbon is a plastic film with a thickness of 1 to 10 m1, such as a polyester film or a polycarbonate film. Film, polyamide film, polyimide film, polyethylene film, etc. can be suitably used.

On the back side of the end detection part (2: other than J) of the support, there is a back side 1i in which opaque powder is mixed and dispersed in a binder.
1 [4] is provided.

As the binder, it is appropriate to use one or a mixture of two or more of silicone resins, epoxy resins, melamine resins, phenol resins, fluororesins, nitrocellulose, and the like.

In addition to the above-mentioned opaque powder, this back layer (4) contains additives such as fluororesin powder, molybdenum disulfide powder, diatomaceous earth,
One type or two or more types of silicone oil or the like may be mixed and dispersed.

These compositions contain 5 to 100319 parts of binder, especially 10 to 50 parts by weight, and additives of 0 to 50 parts by weight, and 0.1 to 50 parts by weight, per 10 parts of opaque powder.
The amount is preferably 20 parts by weight.

If the amount of the binder is too large, there will be a problem of insufficient opacity, and if it is too small, the strength of the coating film of the back surface FJ [4) will be reduced, resulting in the problem of peeling off from the support.

Furthermore, if the amount of the additive is too large, the strength of the coating film of the back layer decreases, resulting in the drawback that the coating layer peels off from the support.

As the opaque powder, carbon black, aluminum powder, titanium oxide, and other transparent pigments can be suitably used alone or in combination of two or more.

The coating amount of the back layer (4) is 0.01 to 5.0 (It
/m < 0.1 to 1.0 g/ffl is preferable; if the coating amount is too large, the thermal conductivity from the thermal head to the ink layer will deteriorate and the transferability of the printed image will decrease. If the amount is too low, there will be a drawback of insufficient opacity.

The heat-sensitive transfer ink layer (3) is a heat-melt transfer type ink layer composed of a heat-melt vehicle or the like, using a conventionally known pigment or dye as a coloring agent, or a heat-melt transfer type ink layer made of a heat-melt vehicle or the like, or a sublimation dye mixed and dispersed in a binder. It may be of any type of heat-sensitive sublimation transfer type in which the sublimation dye is sublimated and transferred by heating with a thermal head.

Next, examples will be illustrated.

The various back layers shown in Table 1 are formed by coating and drying the back layer of a polyester film (4 layers thick), which has a heat-sensitive transferable ink layer of one color of yellow, magenta, or cyan on the surface. be.

The end sensor used in the experiment is as shown in Figure 1, and the emitter (5) and receiver (6) are placed in front of the print image forming position so as to sandwich the printer's ribbon running path. When the end detection unit (2) reaches the relevant position, the light from the emitter (5) that has been blocked by the back layer reaches the light receiver (6), and the light is received by the light receiver (6). , so that the end detection section is detected.

Using this end sensor, ribbon detection tests of this example were repeatedly conducted, and all of the examples were able to reliably detect the presence of the end detection portion.

Also, in a printing test using a thermal head, there was no sticking phenomenon in which the back side of the substrate adhered to the thermal head.

[Margin below]

[Brief explanation of drawings]

FIG. 1 is a plan view showing an example of the layered structure of a ribbon and an optical sensor of the present invention.

Claims (1)

[Claims] 1. In a color thermal transfer ribbon in which a thermal transfer ink layer of a color other than black is provided on the surface of a strip-shaped film support, and a transparent end detection part is provided at the end of the support, the end detection part is A color thermal transfer ribbon comprising a back layer formed by dispersing and mixing an opaque powder in a resin binder that does not adhere to the thermal head over almost the entire back surface of the support.