JPS6295261A - 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 the back surface holding member provided on the back surface of the receiving article and a follower member having a plurlality of fine wires having rigidity fixed thereto at one ends thereof to press both of them. CONSTITUTION:Ink 11 melted under heating is transferred to receiving paper 12 by a pressure transfer mechanism 46. The transfer mechanism 46 holds receiving paper 12 and a current supply thermal transfer film 13 between said mechanism 46 and a platen 46 being a back surface holding member to press both of them. A brush like leading end part 54 being a follower member is engaged with a guide 53 and pressed to the platen 46 by a spring 55 from the interior of the guide 53 to pressurize the platen 46. Further, an electric heater 56 for heating the transfer mechanism 46 and a temp. sensor 56 for monitoring the temp. of the transfer mechanism are arranged on the back surface of the transfer mechanism 46 in the vicinity f the leading end thereof. Because the follower member is formed by embedding a plurality of elastic wire wires 83 in a base part 84, the ink 11 of the current supply thermal transfer film 13 can be contacted with and pressed to the recessed parts 33 of the receiving part 12.

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. 1(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. 3(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 2.
The main reason for this is that the drum 1 does not come into contact with the concave portion 32 of the transferred object 12, resulting in dry I/missing.

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 heat resistance, this idea is suitable for low-speed printing equipment with less temperature load. can only be applied.

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 transfer means includes a back surface holding member provided on the back surface of the object to be printed, and one end of a plurality of thin wires having rigidity. It is characterized by a mechanism that holds and presses the object to be printed and the film-like recording medium between a following member to which is fixed, the back surface holding member, and the following member.

[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). Further, the conveyance speed of the transfer paper and the electrically conductive thermal transfer film was approximately 57 mm/sec. This corresponds to the speed at which one minute can be printed on 12 sheets of A4 paper.

Reference numeral 12 denotes a transfer paper, which is supplied by a transfer paper supply roller 42 . Reference numeral 13 denotes an electrically conductive thermal transfer film, which is fed out from a film supply roller 43, undergoes a printing process, and then is wound up by a film take-up roller 44. The structure of the electrically conductive thermal transfer film 43 includes a base layer 10 made of a 6 μm thick polyethylene terephthalate film (PET), a resistance layer 14 coated on one side of the base layer, and an ink layer 11 coated on the other side. The resistance layer 14 is made by dispersing 20 TfL carbon powder in a resin. The resistance value was approximately 1 to Ω/am2. Reference numeral 46 denotes a transfer mechanism for pressure-transferring the ink onto the transfer paper, which holds and presses the transfer paper 12 and the electrically conductive thermal transfer film 13 between it and a platen 47, which is a back side holding member. As shown in FIG. 1(b), the transfer mechanism 46 has a brush-shaped tip 54, which is a follower member, fitted into a guide 53, and further presses the tip 54 against the platen from within the guide 53 by a spring 55. 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. 58 is a fulcrum for stabilizing the path of the electrically conductive thermal transfer film. Reference numeral 21 denotes a current-carrying recording head consisting of a recording electrode 20 and its support 58. Reference numeral 80 denotes a base upon which the electrically conductive thermal transfer film 13 is pressed by the recording head 21. In order to ensure good contact between the recording electrode 20 and the resistance layer 14, a material was used that was sufficiently smooth and elastic, and to which the molten ink 11 would not adhere. In this embodiment, silicone rubber was used as the material. The recording frequency is 1,5
m5ec/1ine. Further, the distance from the contact point of the recording head with the energized thermal transfer film to the contact point of the transfer mechanism with the energized thermal transfer film is about 5 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, the resistance layer 14 of the current-carrying thermal transfer film is strongly pressed against the recording electrode 12 by a mechanism 81 that presses the tip of the recording head against the current-carrying thermal transfer film 13 . At this time, the base 80
Since it is an elastic body, it follows the recording head without any problem even if the linearity of the etched portion 60 is somewhat poor. Therefore, recording electrode 2
0 and the resistance layer 14, and of course 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 generated by the electric current flowing through the resistance layer 14 . 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 ink to the paper to be transferred by a transfer mechanism, which will be described later, will be referred to as a 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.

Since the ink transport time from the heating process to the transfer process is about 50 m5 ec, the pressure transfer mechanism can transfer the ink to the transfer paper even if it is cooled by the atmosphere. 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 mechanism by an electric heater 56 and a temperature sensor 57 on the back of the transfer mechanism. In this example, the temperature of the ink during the transfer process was controlled to be 30 to 60'C with respect to the room temperature change gjJ-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.

The following member at the tip of the transfer mechanism is a plurality of thin elastic wires 83.
is embedded in the base 84. 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. In this embodiment, if the thin wire 83 is a tungsten wire with a diameter of 100 μm cut into 5 mm lengths and embedded in the resin base 84 in four rows at a pitch of 200 μm, heat conduction will be improved when performing the temperature control. This has advantages such as less sliding wear with the resistance layer 14. By the way, the width of the concave portion of transfer paper (for example, pound paper) with Bekk smoothness of 10 seconds or less is 50 to 200 μm.
The depth is about 50 μm and the distribution is wide. Therefore, it was more effective to use the wire system of the above-mentioned elastic thin wire of 50 to 200 μm. Further, the platen 47, which serves as a back support member in the pressure transfer mechanism, 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 mechanism 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 possible to print well on pound paper with a Beck smoothness of 8 seconds or more. Good printing was possible.

[Effects of the Invention] As described above, according to the present invention, the pressure transfer means fixes one end of a plurality of thin wires having rigidity to a back surface holding member provided on the back surface of the object to be printed. The mechanism is such that the object to be printed and the film-like recording medium are held and pressed between the following member, the back surface holding member, and the following member, so that the heated and melted ink can be applied to the transfer sheet with a rough surface. It makes good contact with the concave portions of the surface, and can print well even on objects with rough surfaces.

Although the present embodiment has been described using an energized thermal transfer recording method as an example, the present invention has similar effects in a thermal transfer recording method as well.

[Brief explanation 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 explaining the conventional problem. FIG. 3 is a diagram showing a conventional thermal transfer recording method. 12...Printed object 13...Thermal transfer film 20...Recording electrode 21...Recording head 46...Transfer member 56...Heater 57...Temperature sensor 83...Following member or higher

Claims (1)

[Claims] A film-like recording medium having a layer of ink activated by thermal stimulation and selectively pressure-transferred to a printing medium, means for selectively heating the ink, and heating the ink activated by the heating means. In the printing device, the pressure transfer means includes a back surface holding member provided on the back surface of the object to be printed, and a follower member to which one end of a plurality of thin wires having rigidity is fixed. A printing apparatus characterized in that the printing apparatus is a mechanism that holds and presses the object to be printed and the film-like recording medium between the back surface holding member and the following member.