JPH0696291B2 - Printing device - Google Patents

Description

The present invention relates to a printing apparatus using a thermal transfer recording system.

[Prior Art] In the thermal transfer recording method, as shown in FIG. 3 (a), when the heat-meltable ink 11 applied to the film substrate 10 is selectively heated and melted by the thermal head 15 having the electric heating element 16. At the same time, it is a printing method in which the ink 11 is polymerized on the transferred material 12 and transferred under pressure to obtain an image.

FIG. 3 (b) is a diagram for explaining an energization heat transfer method which is a modification of the above-mentioned heat transfer recording method. It is composed of an ink carrier 13 having a layer 14 and a recording head 21 having a recording electrode 20 for supplying a current to the electric heating layer 14. Each recording method has features such as silent printing, pigment-based ink can be used for high density printing, colorization is easy, print head is easy to print, and high speed printing is possible. .

[Problems to be Solved by the Invention] However, in the above-mentioned conventional example, although a good print can be obtained on a print having a smooth surface, a good print can be obtained on a transfer target having a rough surface. I had a problem that I could not get a copy.

The above problem is as shown in FIG.
The main reason for this is that dots do not occur because of the non-contact between the concave portions 32 of the transferred material 12.

There is an idea to make the recording head an elastic body to follow the rough surface of the transfer paper for the above problem, but since the recording head needs heat resistance, this idea is applied to a low-speed printing apparatus with a small temperature load. Only applicable.

In particular, bond paper, which is used as an official document in Europe and the United States, cannot print due to the above reasons, which is a factor that prevents the spread of the thermal transfer method.

Therefore, the present invention solves such a problem, and an object of the present invention is to provide a high-speed and high-quality thermal transfer recording apparatus that does not select the surface shape of the transferred material.

[Means for Solving the Problems] The printing apparatus of the present invention is a printing apparatus for transferring the ink activated on an ink film to a print medium by a heating unit, and the ink film and the print target are printed by the heating unit. After the ink on the ink film has been activated by the heating means, it has a plurality of rigidity-like pressurizing means for pressurizing the print medium via the ink film, on the downstream side in the medium transport direction. The pressurizing means is configured to transfer the ink on the ink film to the print medium under pressure.

[Embodiment] FIG. 1 is a view showing the structure of an electrothermal transfer printing apparatus in an embodiment of the present invention. FIG. 1 (a) shows the entire mechanism of the printing apparatus, and FIG. 1 (b) shows an enlarged view within the broken line 41 in FIG. 1 (a). The transfer speed of the transfer paper and the electrothermal transfer film was set to about 57 mm / sec. This is A4 paper per minute
This is equivalent to the speed at which 12 sheets can be printed.

12 is a transfer paper, which is supplied from a transfer paper supply roller 42. 13 is an electric heat transfer film, which is a film supply roller
After being fed out from 43 and undergoing a printing process, it is wound around a film winding roller 44. The structure of the electric heat transfer film 13 is a 6 μm thick polyethylene terephthalate film (PE
T) is used as the base layer 10, and the resistive layer 14 is applied to one of the base layers and the ink layer 11 is applied to the other. The resistance layer 14 is a resin in which 20% by weight of carbon powder is dispersed. Resistance value is about 1k
It was Ω / cm ² . Reference numeral 46 denotes a transfer mechanism for pressure-transferring the ink to the transfer paper, which holds the transfer paper 12 and the electrothermal transfer film 13 between the platen 47 which is a back surface holding member and presses them. As shown in FIG. 1B, the transfer mechanism 46 fits the brush-like tip end portion 54, which is a follow-up member, into the guide 53, and further presses the tip end portion 54 against the platen by the spring 55 from inside the guide 53. Further, an electric heater 56 for heating the transfer mechanism and a temperature sensor 57 for monitoring the temperature of the transfer mechanism are installed on the back surface near the tip of the transfer mechanism. Reference numeral 58 is a fulcrum for stabilizing the path of the electrothermal transfer film. An energization recording head 21 is composed of the recording electrode 20 and its support 59. Reference numeral 80 is a base body when the recording head 21 presses the electrothermal transfer film 13. A material that is sufficiently smooth and made of an elastic material and that does not adhere to the melted ink 11 is used so that the contact between the recording electrode 20 and the resistance layer 14 is good. In this embodiment, silicon rubber is used as the material.
The recording frequency was 1.5 msec / line. Further, the distance from the contact point of the recording head to the electrically conductive heat transfer film to the contact point of the transfer mechanism to the electrically conductive heat transfer film is about 5 mm.

Next, the operation of the above configuration will be described. Film supply roller
The current-carrying thermal transfer film 13 fed from 43 is in contact with the recording electrode 20 at the edge portion 60 of the current-carrying recording head 21. At this time, the resistance layer 14 of the electrothermal transfer film is strongly pressed against the recording electrode 12 by the mechanism 81 for pressing the tip of the recording head against the electrothermal transfer film 13. At this time, since the base 80 is an elastic body, it can follow the edge portion 60 of the recording head without problems even if the linearity of the edge portion 60 is somewhat poor. Therefore, good electricity can be applied between the recording electrode 20 and the resistance layer 14, and naturally, it does not depend on the surface condition of the transfer paper at all. In this manner, the selected portion of the ink layer 11 is heated and melted by the heat generation of the resistance layer 14 when electricity is applied. Hereinafter, the process of heating and melting the ink by the recording head will be referred to as a heating process, and the process of transferring the ink to the transfer target paper by a transfer mechanism described below will be referred to as a transfer process.

The ink heated and melted in the above steps is transferred to the transfer paper by the pressure transfer mechanism according to the present invention. Since the ink transfer time from the heating process to the transfer process is about 50 msec, it is possible to transfer to the transfer target paper by the pressure transfer mechanism even when cooled by the atmosphere. However, if the room temperature fluctuates, the temperature of the ink during transfer also changes and the optimum transfer viscosity cannot be maintained stably.
The temperature sensor 57 appropriately heats the ink through the transfer mechanism. In this example, the temperature of the ink during the transfer process was controlled to be 30 to 60 ° C against the room temperature fluctuation of -5 to 45 ° C. If the temperature is lower than 30 ° C, the viscosity of the melted ink becomes high when heated and the transfer becomes unstable, and if the temperature is higher than 60 ° C, the viscosity of the ink that is not melted at the time of heating lowers and causes smear.

The follower member at the tip of the transfer mechanism has a plurality of elastic thin wires 83 embedded in the base portion 84. With such a structure, it becomes possible to press the ink 11 of the electrothermal transfer film in contact with the concave portion 33 of the transfer paper. In this embodiment, a tungsten wire having a diameter of 100 μm is cut into a thin wire 83 into a length of 5 mm, and four rows are formed at a pitch of 200 μm and embedded in a resin base portion 84. The use of a tungsten wire has effects such as good heat conduction when performing the temperature control and low sliding friction with the resistance layer 14. By the way, the width of the concave portion of the transferred paper (for example, bond paper) having a Beck smoothness of 10 seconds or less is 50 to 200 μm and the depth thereof is about 50 μm, and the distribution thereof is wide. Therefore, the elastic thin wire system is 50 to 20
The use of 0 μm was more effective. Further, the platen 47, which serves as the back surface supporting member in the pressure transfer mechanism, is preferably hard in order to efficiently apply pressure. In this embodiment, NBR is used and its hardness is 5
The effect was further enhanced by using a material of 0 degree or more.

By applying the heated ink to the transfer paper by the transfer mechanism having the above structure, the ink is sufficiently contacted even with the concave portion on the surface of the transfer paper, and the ink is reliably transferred.

When an attempt was made to actually print with the above-described structure of the present invention, the conventional Beck smoothness was only good for thermal transfer dedicated paper of 200 seconds or more. Good printing was possible.

EFFECTS OF THE INVENTION As described above, according to the present invention, the means for transferring pressure fixes one end of a plurality of rigid thin wires having a back surface holding member provided on the back surface of the object to be printed. By the mechanism for sandwiching and pressing the object to be printed and the film-shaped recording medium between the following member, the back surface holding member, and the following member, the heat-melted ink has a rough surface to be transferred paper. It also makes good contact with the concave portions and can perform good printing even on an object to be printed having a rough surface.

In this embodiment, the electrothermal transfer recording method has been described as an example, but the present invention has the same effect in the thermal transfer recording method.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the structure of a printing apparatus according to the present invention. FIG. 2 is a diagram for explaining a conventional problem. FIG. 3 is a diagram showing a conventional thermal transfer recording system. 12 …… Object to be printed 13 …… Thermal transfer film 20 …… Recording electrode 21 …… Recording head 46 …… Transfer member 56 …… Heater 57 …… Temperature sensor 83 …… Follow-up member

Claims (2)

[Claims] 1. A printing apparatus for transferring an ink activated on an ink film to a print medium by a heating means, wherein the ink film is provided downstream of the heating means in the conveying direction of the ink film and the print medium. The ink on the ink film is activated after the ink on the ink film is activated by the heating means, and the pressure means presses the ink on the ink film. A printing apparatus, wherein the printing apparatus is configured to be pressure-transferred onto the printing medium. 2. The printing apparatus according to claim 1, wherein the pressurizing means includes a heater.