JPS6295260A - Printing apparatus - Google Patents

Abstract

PURPOSE:To provide a high speed and high quality thermal transfer recording apparatus independently of the surface configuration of a receiving article, by constituting a pressure transfer means of a mechanism holding the receiving article and a film like recording medium between an elastomer and a back surface holding member to press both of them. CONSTITUTION:A transfer blade 46 holds receiving paper and a current supply thermal transfer film 13 between said blade 46 and a platen 47 to press both of them. A press mechanism 48 presses the transfer blade 46 to the platen 47 through a fulcrum 19 in the axial direction of said platen 47 and this platen 47 is a back surface holding member for holding receiving paper 12 being an article to be printed. The current supply thermal transfer film 13 delivered from a film supply roller 43 is contacted with a recording electrode 20 at the edge part 60 of a current supply recording head 21. Therefore, good current supply is enabled between the recording electrode 20 and a resistance layer 14 and the recording head is perfectly independent of the surface state of the receiving paper 12. By this method, the selected part 61 of an ink layer 11 is melted under heating by the current supply heating of the resistance layer 14.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a printing apparatus using a thermal transfer recording method.

[Prior Art] As shown in FIG. 4(a), the thermal transfer recording method selectively heats and melts heat-melting ink 11 coated on a film-like substrate 10 using a thermal head 15 having an energized heating element 16. This is a printing method in which the ink 11 is simultaneously polymerized onto the transfer target 12 and transferred under pressure to obtain an image.

Further, FIG. 4(b) is a diagram for explaining an electric thermal transfer method which is a modification of the above-mentioned thermal transfer method, in which the film-like substrate 10
From a recording head 21 having an ink transport body 13 having the heat-melting ink 11 on one side and an energizing heat generating layer 14 on the other side, and a recording electrode 20 for passing a current through the energizing heat generating layer 14. Become. Both recording methods allow silent imprinting.
It has the characteristics of being able to use pigment-based ink, allowing high-density printing, easy color printing, easy line formation of the recording head, and high-speed printing.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional example, although good printing can be obtained for objects with smooth surfaces, it is not possible to obtain good impressions for objects with rough surfaces. There was a problem that a print could not be obtained.

The above problem is caused by heating and melting ink 3 as shown in Figure 3.
The main reason for this is that the dots 1 do not come into contact with the concave portion 32 of the transferred object 12, resulting in missing dots.

To solve the above problem, there is an idea to make the recording head an elastic body and make it follow the rough surface of the transfer paper, but since the recording head needs to be heat resistant, this idea is not suitable for low-speed printing equipment with less heat stress. It can only be applied to

Particularly, bond paper, which is used for official documents in Europe and the United States, cannot be printed due to the above-mentioned reasons, which is a factor preventing the spread of thermal transfer methods.

The present invention is intended to solve these problems, and its purpose is to provide a high-speed, high-quality thermal transfer recording device that can be used regardless of the surface shape of the object to be transferred.

[Means for Solving the Problems] In the printing apparatus of the present invention, the pressure means includes a back surface holding member provided on the back surface of the object to be printed, an elastic body, and the elastic body and the back surface holding member. It is characterized by a mechanism that sandwiches and presses the object to be printed and the film-like recording medium therebetween.

[Embodiment] FIG. 1 is a diagram showing the structure of an electric thermal transfer printing device in an embodiment of the present invention. FIG. 1(a) shows the mechanism of the entire printing apparatus, and FIG. 1(b) shows an enlarged view of the area within the broken line 41 in FIG. 1(a). Reference numeral 12 denotes a transfer paper, and 13 is an electrically conductive thermal transfer film fed by a transfer paper supply roller 42, which is fed out by a film supply roller 43, undergoes a printing process, and then is wound up by a film take-up roller 44. 45
is a mechanism that applies tension to the electrically conductive thermal transfer film in the direction of arrow A. The structure of the electrically conductive thermal transfer film 12 includes a base layer 10 made of polyethylene terephthalate film (PET) with a thickness of 6 μm, a resistive layer 14 coated on one side of the base layer, and an ink layer 11 coated on the other.The resistive layer 14 is made of 20% by weight carbon. Powder is dispersed in resin. The resistance value is approximately 1 to 0
It was 7cm2. Further, the conveyance speed of the transfer paper, the electrically conductive thermal transfer film, and the lumen was approximately 57 mm/sec. This is 1
This corresponds to the speed at which 12 sheets of A4 paper can be printed.

Reference numeral 46 denotes a transfer blade for transferring the ink to the transfer paper, and the transfer blade 46 holds and suppresses the transfer paper 12 and the electrically conductive thermal transfer film 13 between it and the platen 47 .

48 is a suppressing mechanism for pressing the transfer blade 46 through the fulcrum 49 in the axial direction of the platen 47. The platen 47 is a back side holding member that holds the transfer paper 12, which is an object to be printed. The transfer blade 46 is shown in FIG. 1(b).
As shown in the figure, an elastic body 54 is bonded to the tip of a plate-shaped metal 53, and a plurality of hard particles 55 are bonded to the tip of the elastic body 54. Further, on the back surface near the tip of the metal plate 53, there is an electric heater 56 for heating the transfer blade 46 and a temperature sensor 57 for monitoring the temperature of the transfer blade.
There is a C installed. 58 is a fulcrum for stabilizing the path of the thermal transfer film. Reference numeral 21 denotes a current-carrying recording head consisting of a recording electrode 20 and its support 58. The recording frequency is 1
, 5 m5ec/1ine. Further, the distance from the contact point of the recording head 21 with the energized thermal transfer film 13 to the contact point of the transfer blade 46 with the energized thermal transfer film 13 is about 3 mm.

Next, the effects of the above configuration will be described. The energized thermal transfer film 13 fed out from the film supply roller 43 comes into contact with the recording electrode 20 at the edge portion 60 of the energized recording head 21 .

At this time, since tension is applied in the direction of arrow A by the mechanism 45 for applying tension to the electrically conductive thermal transfer film, the resistance layer 14 of the electrically conductive thermal transfer film is strongly pressed against the recording electrode 20. Moreover, since the base layer of the electrically conductive thermal transfer film 13 is made of a polymer resin and has ductility, it can follow the etched portion 60 of the recording head without any problem even if the linearity is somewhat poor. Therefore, good current conduction is possible between the -C recording voltage W&20 and the resistance layer 14, and of course it does not depend on the surface condition of the transfer paper 120 at all. In this manner, the selected portion 61 of the ink layer 11 is heated and melted by the heat generated by the electric current in the resistance layer 14 . Hereinafter, the process of heating and melting the ink by the recording pad 21 will be referred to as the heating process, and the process of transferring the ink to the transfer paper by the transfer blade 46, which will be described later, will be referred to as the transfer process.

The ink heated and melted in the above steps is transferred onto the transfer paper by the pressure transfer mechanism according to the present invention.

The transport time of the ink from the heating process to the transfer process is about 50 m5ec, so even if it is cooled by the atmosphere, it still maintains a molten viscosity that allows transfer, and by applying pressure with the transfer blade 46, it is transferred to the paper to be transferred. Transfer becomes possible. However, if the room temperature fluctuates, the temperature of the ink during transfer also changes and the optimum viscosity for transfer cannot be stably maintained, so the ink is appropriately heated through the transfer blade 46 by an electric heater 56 and a temperature sensor 57 on the back of the transfer blade. . In this example, the temperature of the ink during the transfer process was controlled to be 30 to 60°C with respect to room temperature fluctuations of -5 to 45°C. If it is less than 3000, the viscosity of the ink melted during heating becomes high and transfer becomes unstable, and if it exceeds 60° C., the viscosity of the ink that is not melted during heating causes sagging marks.

At the tip of the transfer blade 46, an elastic body 54 is connected to a metal body 5.
It is glued to 3. Furthermore, a plurality of hard particles 55 are embedded in the end face of the elastic body 54. By adopting such a structure, it becomes possible to contact and press the ink 11 of the electrically conductive thermal transfer film also against the recessed portions 33 of the transfer paper. Although the effect can be obtained even if the tip of the transfer blade has a structure consisting only of an elastic body, it becomes even more effective by embedding hard particles in the end surface. The reason for this will be explained using Figure 2. 54 is an elastic body, and 12 is a cross section of the rough surface of the transfer paper. 55 is a hard particle. In addition, the elastic body 54
The electrically conductive thermal transfer film between the paper 12 and the transfer paper 12 was omitted.

When applying pressure to the uneven surface of the transfer paper 12 using only an elastic body as shown in FIG. As a result, the recess 33 cannot be pressurized. So the second
As shown in FIGS. (b) and (c), if hard particles 55 are embedded in the surface of the elastic body 54, the amount of deformation of the elastic body to follow the same unevenness gap can be reduced. Furthermore, as in this embodiment, since the elastic body moves while applying pressure to the transfer paper in the direction of arrow B, there is a certain probability that the recesses 34 that could not be pressed in FIG. It becomes possible to apply pressure as shown in (C). In addition, wear resistance is also improved by embedding hard particles. In this embodiment, the elastic body 54 is made of acrylonitrile butadiene rubber (NBR), the hard particles 55 are made of alumina particles with a coarse diameter of 30 to 100 μm, and NBR is used as the elastic body 54.
When molding BR, the alumina particles were mixed on the surface. By the way, the width of the concave portion of transfer paper (for example, pound paper) having a Bekk smoothness of 10 seconds or less is 50 to 200 μm, the depth is about 50 μm, and the distribution thereof is wide. Therefore, it was more effective to mix the rough type of hard particles 55 with a variety of branch yarns of 50 to 200 μm. The arrangement density of the hard particles 55 may be such that the hard particles do not come into contact with each other. In addition, the platen 47, which serves as a lower basin when pressure transfer is performed with a transfer blade, is preferably hard in order to apply pressure efficiently. In this example, the effect was further enhanced by using NBR with a hardness of 50 degrees or more.

By pressurizing the heated ink onto the paper to be transferred by the transfer blade 46 having the above structure, the ink sufficiently contacts even the recesses on the surface of the paper to ensure ink transfer.

When we actually attempted printing using the configuration of the present invention described above, we found that while conventional printing was only possible on thermal transfer paper with a Beck smoothness of 200 seconds or more, it was also possible to print on bond paper with a Beck smoothness of 8 seconds. Good printing was possible. Furthermore, when the configuration of the present invention is used, the ink does not come into contact with the transfer paper during the heating process, so the heat does not escape to the transfer paper, so the printing efficiency is improved. When the transfer paper and the electrical thermal transfer film were heated in a polymerized state, the printing energy was 7 mJ per millimeter squared, but in this example, it was 4.5 mJ. Printing efficiency has improved by approximately 35%.

Although the present embodiment has been described with reference to an electrically conductive thermal transfer recording method, the present invention can also achieve similar effects in a thermal transfer method.

[Effects of the Invention] As described above, according to the present invention, the pressure transfer means is arranged between a back surface holding member and an elastic body provided on the back surface of the object to be printed, and between the elastic body and the back surface holding member. Since the mechanism is such that the material to be printed and the film-like recording medium are sandwiched and pressurized, the heated and melted ink can be brought into good contact even with the paper having a rough surface. It is also effective in obtaining good prints on objects to be transferred.

Furthermore, since the ink and the object to be transferred are not brought into contact during the heating process, the applied heat does not diffuse to the object to be transferred, resulting in a significant improvement in printing efficiency. Therefore, in the case of the thermal transfer method, the temperature rise of the heating element is lower than that of the conventional method, so the amount of heat stored in the thermal head is small, and high-speed printing is possible.

Furthermore, since the temperature load on the heating element is also reduced, the durability of the heating element and, in turn, the durability of the thermal head is improved. Also, in the case of the energized thermal transfer method, the thermal load and electrical load on the recording electrodes are similarly reduced, and the durability of the energized recording head is improved. In addition, both types have the effect of reducing the load on the power supply of the device and the height of the drive circuit, thereby reducing the manufacturing cost.

BRIEF DESCRIPTION OF THE 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 illustrating the transfer blade used in this example. FIG. 3 is a diagram explaining the conventional problem. FIG. 4 is a diagram showing a conventional thermal transfer recording method. IO... Base film 11... Ink layer 12... Transferred object 13... Thermal transfer film 20... Recording electrode 21... Recording head 46... Transfer blade 54...Elastic body 55...Hard particles or more

Claims (2)

[Claims] (1) A film-like recording medium having a layer of ink that can be activated by thermal stimulation and selectively pressure-transferred onto an object to be printed, a means for selectively heating the ink, and a layer of ink activated by the heating means. In the printing apparatus, the pressure transfer means includes a back surface holding member provided on the back surface of the object to be printed, an elastic body, and a space between the elastic body and the back surface holding member. 1. A printing apparatus comprising a mechanism for sandwiching and pressing the object to be printed and the film-like recording medium. (2) The printing apparatus according to claim 1, wherein hard particles are arranged between the elastic body of the pressure transfer means and the film-like recording medium.