JPS62162576A - Thermal transfer printer - Google Patents

Abstract

PURPOSE:To enable a heat-resistant slipping layer to be omitted and ensure uniform printing, by providing a lubricant coater for applying a heat-resistant lubricant to the back side of a thermal transfer film on the upstream side of a thermal head of a thermal transfer printer. CONSTITUTION:Before a thermal transfer film 1 reaches a thermal head 7, a silicone oil 11 is applied to the back side (the side brought into contact with the head 7) of the film 1 by a lubricant coater 10. Therefore, when the film 1 is passed on the head 7, the silicone oil in the form of a thin film is present therebetween. The silicone oil film reduces friction between the film 1 and the head 7, and prevents a base film 2 of the film 1 from being heated in excess. Accordingly, thermal transfer can be performed without any trouble even on a thermal transfer film not having a heat-resistant slipping layer on the back side of the base film 2.

Description

DETAILED DESCRIPTION OF THE INVENTION C. Industrial Application Field The present invention relates to a thermal transfer printer using a thermal transfer film having a coloring material layer provided on the surface of a support film.

[Conventional technology]

In a thermal transfer printer, a thermal transfer film and an image receiving substrate are overlapped and passed between a thermal head and a platen roll, and the thermal head melts the color material layer of the thermal transfer film or sublimates the dye in the color material layer to receive the image. It is transferred to the substrate. The thermal transfer film 1 used for this thermal transfer usually consists of a support film 2 such as a PET film, and a coloring material layer 3 formed on one side of the support film 2 and a predetermined pigment or dye and a binder, as shown in FIG. 1O. and a heat-resistant slip layer 4 formed on the opposite side. This heat-resistant slip layer 4 prevents the support film 2.2 from melting when heat is applied to the heat-sensitive transfer film 1 by a thermal head, and also prevents the heat-sensitive transfer film 1 from rubbing on the stationary thermal head. This is provided to reduce friction when driving. With conventional thermal transfer printers,
If this heat-resistant slip layer 4 were not present, the friction between the thermal head and the thermal head would be too large, making running unstable.
Furthermore, melting occurs in the support film 2, resulting in film cutting, thermal head staining, sticking (poor running), etc.

This heat-resistant slip layer 4 is essential.

[Problem that the invention seeks to solve]

However, the conventional heat-resistant slip layer 4 causes various problems. That is.

(1) The heat-resistant slip layer has an uneven thickness (it is difficult to make it uniformly. If the heat-resistant slip layer has an uneven thickness,
This causes unevenness in the heat transfer coefficient, making one image uneven. Further, when a coloring layer is provided after heat-resistant slip layer 5 is provided, if the thickness of the heat-resistant slip layer is uneven, the thickness of coloring layer 9 will also be uneven, resulting in unevenness in one image.

If the heat-resistant slip layer has an uneven thickness, the surface of the image-receiving substrate will be embossed according to the uneven thickness during thermal transfer, resulting in an unsightly appearance. In particular, in the case of sublimation transfer, since the surface of the image receiving substrate is coated with resin, it is easily embossed, which is a problem.

(2) At present, there is no heat-resistant slip layer with sufficient heat resistance. In particular, in the case of sublimation transfer, sufficient image density cannot be obtained unless a large amount of heat is applied, so a slip layer with excellent heat resistance is required, but this is not available. So 1
At present, we have no choice but to thicken the heat-resistant slip layer. If the heat-resistant slip layer is thick, heat transfer to the two color material layers will be poor, leading to problems such as the inability to increase the transfer speed sufficiently and the resolution of the transferred image to be poor.

(3) Since the heat-sensitive transfer film is usually stored in a rolled state, one color material layer and the heat-resistant slip layer are in contact with each other.

A heat-resistant slip layer cannot be used as it will degrade the color material layer.

There are many restrictions on materials.

The present invention was made in view of such conventional problems, and an object of the present invention is to provide a thermal transfer printer that can perform good transfer even if the heat-sensitive transfer film does not have a heat-resistant slip layer on the back side. shall be.

[Means for solving problems]

The present invention, which was made to achieve the above object, comprises providing a coloring material layer on the surface of a support film! S In a thermal transfer printer that transfers to an image receiving substrate by applying heat to the thermal transfer film from the back side with a thermal head.

The gist of the present invention is a thermal transfer printer characterized in that a slip agent applying device for applying a heat-resistant slip agent to the back surface of a heat-sensitive transfer film is provided upstream of a thermal head.

The heat-resistant slip agent used here has a heat resistance that does not cause any problem even if it comes into contact with the thermal head, and by applying it to the heat-sensitive transfer film, it can be applied to the heat-sensitive transfer film when it passes through the thermal head. intervening between.

It reduces the friction between the two, and it does not matter whether it is liquid or solid (including powder). As a heat-resistant slip agent.

Liquids such as silicone oil, mineral oil, and lubricating oil, powders such as fluororesin powder, glass lift, molybdenum disulfide, and graphite, and dispersions thereof can be used.

[Effect]

As described above, in the present invention, a heat-resistant slip agent can be applied to the back surface of the heat-sensitive transfer film (the side that contacts the thermal head) upstream of the thermal head, and this heat-resistant slip agent The support film is interposed between the thermal transfer film and the thermal head, and it is possible to always improve the slippage between the thermal transfer film and the thermal head, and to protect the support film from the heat of the thermal head. As a result, it is possible to omit the heat-resistant slip layer on the back side of the heat-sensitive transfer film.

When a heat-resistant slip layer is used, higher speed transfer recording, higher resolution transfer recording, higher density recording, etc. are possible.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a thermal transfer printer according to an embodiment of the present invention. In the figure, the symbol ``■'' indicates a heat-sensitive transfer film, which is fed out from a supply pobin 5 on the left and wound onto a take-up pobin 6 on the right. The thermal transfer film 1 used here is as follows.

As shown in FIG. 9, it is possible to use a support film 2 such as a PET film with only a coloring material layer 3 provided on one side thereof. Of course, as the heat-sensitive transfer film 1, the same one as the conventional one having a heat-resistant slip layer 4 as shown in FIG. 1O may be used. In FIG. 1, 7 is a thermal head, 8 is an image receiving substrate such as recording paper, and 9 is a thermal transfer film 1.
This is a platen roll that overlaps and presses the image receiving substrate 8 and the image receiving substrate 8 against the thermal head 7. A heat-resistant slip agent application device 10 is provided on the upstream side of the thermal hend door with respect to the running direction of the heat-sensitive transfer film. In this embodiment, silicone oil is used as the heat-resistant slip agent.

The slip agent applying device 10 is shown enlarged in FIG.

A tank 12 containing silicone oil 11 and a felt 13 having one end immersed in the silicone oil 11.

The felt 13 applies silicone oil to the back surface of the heat-sensitive transfer film 1 (the surface opposite to the C color material layer 3). The slip agent applying device 10 is not limited to the one shown in FIG. 2 and can be modified in various ways. For example, as shown in FIG. material 15, as shown in FIG. 4, a backup roll 14. Silicone oil bath16. Coating roll 17. As shown in Fig. 5, a felt 19 is used instead of the doctor 18 in Fig. 4, and as shown in Fig. 6, an inkjet type silicone oil injection nozzle 20 is used. It can be used as something.

Further, the backup roll 14 may not be provided.

Next, the operation of the thermal transfer printer will be explained.

The thermal transfer film 1 is fed out from the supply bobbin 5.

The thermal head 7 is overlapped with the image receiving substrate 8 and runs between the thermal head 7 and the platen roll 9, and during this time, the coloring material layer 3 at a predetermined position is melted by the thermal head 7, or the dye in the coloring material layer 3 is sublimated, and the image receiving substrate 8 One image is recorded. Before this thermal transfer film l reaches the thermal head door, silicone oil is applied to its back surface (where it comes into contact with the thermal head) by a slip agent applying device 10.
Therefore, when the thermal transfer film 1 passes over the thermal head 7, a thin film of silicone oil is present between the two. This silicone oil film reduces friction between the thermal transfer film 1 and the thermal head 7 and prevents the support film 2 of the thermal transfer film 1 from being excessively heated. Thus, as shown in FIG. 9, thermal transfer can be performed without any problem even on a thermal transfer film that does not have a heat-resistant slip layer on the back surface of the support film 2. In other words, thermal transfer can be performed without any problem.

In the thermal transfer printer of the above embodiment, it is possible to use a heat-resistant transfer film that is not provided with a heat-resistant slip layer on the back surface.

Here, the amount of silicone oil to be applied may be extremely small since it has a large friction reducing effect. Too much coating will inhibit heat transfer and impair resolution. The amount of silicone oil applied is preferably about 1 mg/rd to 1 g/rr+. It is preferable to uniformly apply this silicone oil to the back surface of the heat-sensitive transfer film 1, since the thermal head 7 itself has the function of squeezing the silicone oil on the back surface of the heat-sensitive transfer film 1 to make it uniform.

Uniform application is not particularly important. Therefore, as shown in FIG. 7, silicone oil 2.
1 may be given intermittently. Also in this case.

The thermal head 7 squeezes this silicone oil 21 into a thin film 22, so that a film of silicone oil is definitely present between the thermal transfer film 1 and the thermal head 7. Applying silicone oil intermittently in this manner has the advantage that it is possible to apply a very small amount of silicone oil.

In addition, in the above embodiment, the silicone oil application device 1
0 is provided upstream of the thermal head 7 and away from the thermal head 7;
The thermal head 7 may also be provided in the immediate vicinity of the thermal head 7.
It may be provided integrally with the Further, a silicone oil injection nozzle 20 as shown in FIG. 6 may be provided on the upstream side of the thermal head 7 so as to inject silicone oil to the contact area between the thermal transfer film 1 and the thermal head 7.

The silicone oil application device IO may be provided as an inherent device in the thermal transfer printer, but alternatively it can also be provided in a thermal transfer film cassette that is removable from the thermal transfer printer. FIG. 8 shows a cassette 23 used in that case. This cassette 23 is made up of a supply bobbin 5 and a take-up bobbin 6 for the thermal transfer film 1 housed in one case 24, and a silicone Felt soaked in oil 2
5 is set. When the cassette 23 is placed in a predetermined position within the thermal transfer printer.

The thermal head 7 and a platen roll (not shown) are inserted through the window 24A formed in the case 24, and transfer recording is performed. At this time, the felt 25 is inserted into the thermal head 7.
This constitutes an application device that is located upstream of and applies silicone oil to the back surface of the heat-sensitive transfer film 1.

Note that the above two or more examples are those in which silicone oil is used as the heat-resistant slip agent, but as mentioned above, other liquids or solids may be used in addition to silicone oil.

Powder can be used, and a slip agent applying device suitable for the characteristics of the heat-resistant slip agent to be used may be used. for example.

When using a powdered heat-resistant slip agent, a slip agent applying device using static electricity is preferred because it enables uniform application.

[Effects of the Invention] As explained above, the thermal transfer printer of the present invention is provided with an application device for applying a heat-resistant slip agent to the back surface of the heat-sensitive transfer film upstream of the thermal head, and a heat-resistant slip agent is provided on the back surface of the heat-sensitive transfer film. Because it has been added with a lubricant that has properties,
This heat-resistant slip agent is interposed between the heat-sensitive transfer film and the thermal head to ensure good slippage between the heat-sensitive transfer film and the thermal head at all times, and to protect the support film from the heat of the thermal head. It becomes possible. As a result, it becomes possible to omit the heat-resistant slip layer on the back side of the heat-sensitive transfer film, and it is not necessary to apply a heat-resistant slip layer, and one color material layer can be stably formed. Printing unevenness caused by uneven thickness of the heat-resistant slip layer is eliminated. The thickness unevenness of the coloring material layer caused by the thickness unevenness of the heat-resistant slip layer is eliminated. Effects such as a reduction in the manufacturing cost of the heat-sensitive transfer film can be obtained.

In addition, since there is no longer a need for a heat-resistant slip layer on the back side of the thermal transfer film, a protective layer made of a material that does not deteriorate the dye or cause transfer of the dye even if it comes into contact with the color material layer is installed in this area. It is now possible to set up
If such a protective layer is provided, even if the thermal transfer film is stored in a rolled form for a long period of time, the dye will not be transferred to the back side, and the storage stability of the thermal transfer film will be improved. Furthermore, as a result of being able to use a heat-sensitive transfer film with improved storage stability, the thermal head is hardly stained by dyes adhering to the back surface.

Furthermore, the thermal transfer printer of the present invention can also use a thermal transfer film having a heat-resistant slip layer similar to conventional ones. Resolution transcription record.

The effect that high-density recording becomes possible is also obtained.

In addition, when the felt 13 in contact with the thermal transfer film 1 is used as the silicone oil applying device 1O as in the embodiment shown in FIG. 1, this felt 13 has the effect of cleaning the back surface of the thermal transfer film This provides the advantage of preventing dust from adhering to the head and preventing image quality defects due to clumps and the like.

[Brief explanation of drawings]

FIG. 1 is a schematic side view of a thermal transfer printer according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a slip agent applying device 10 used in the thermal transfer printer, and FIGS. 3 to 6 are respectively A cross-sectional view or a side view showing a modified example of the lubricant applying device IO, FIG. 7 is a cross-sectional view of a main part showing an example of applying silicone oil, and FIG. 8 is a schematic cross-section of a thermal transfer film cassette used in another embodiment. 9 are cross-sectional views of a thermal transfer film that can be used in a thermal transfer printer according to the present invention, and FIG. 10 is a cross-sectional view of a conventional thermal transfer film.

Claims (1)

[Claims] In a thermal transfer printer that transfers to an image receiving substrate by applying heat from the back side of a thermal transfer film with a coloring material layer on the surface of a support film using a thermal head, a heat-resistant transfer film is placed on the back side of the thermal transfer film upstream of the thermal head. A thermal transfer printer characterized in that it is equipped with a slip agent applying device that applies a slip agent.