JPS6295254A - Printing apparatus - Google Patents

Abstract

PURPOSE:To provide a high speed and high quality thermal transfer recording apparatus without choice in the surface configuration of a receiving article, by providing a heating means for selectively heating a thermal transfer medium and a transfer means consisting of an elastomer and a rotary support permitting the rotation of said elastomer. CONSTITUTION:Because a current supply thermal transfer film 3 delivered from a film supply roller 4 and contacted with a recording electrode at the edge part of a current supply recording head 7 is constituted so that the substrate layer thereof has ductility, the supply of a current can be well performed between the recording electrode and a resistance layer and the selected part of an ink layer is melted under heating perfectly independent of the surface state of receiving paper 1. Thereafter, ink is transferred under pressure by a transfer means 8. This transfer means 8 is constituted of an elastomer 81, a support substrate 82 for supporting and pressurizing the elastomer 81 and a rotary support 83 and has water pillow effect and, therefore, even if the receiving paper 1 having a rough smoothness is used, transfer pressure can be uniformly applied.

Description

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

[Conventional technology]

The thermal transfer recording method, as shown in FIG.
At the same time, the ink 91 is selectively heated and melted by a thermal head having a thermal head 2, and at the same time, the ink 91 is pressed onto the transfer target 95,
This is a printing method that obtains an image by pressure transfer.

FIG. 8 is a diagram for explaining an electric thermal transfer method, which is a modification of the above-mentioned thermal transfer method. It consists of a recording head having an ink film and a recording electrode 96 for passing a current through the energizing heat generating layer 95. All of the recording methods have features such as silent printing, use of pigment-based ink, high-density printing, easy color printing, easy line formation of the recording head, and high-speed printing.

[Problem that the invention seeks to solve]

However, the above-mentioned conventional example has the problem that although a good print can be obtained for an object with one smooth surface, it is not possible to obtain a good print for an object with a rough surface. Was.

The cause will be explained with reference to FIGS. 9(a) + (b) and (c).

First, the heated and melted ink 101 does not come into contact with the concave portion 102 of the transferred object 93, so that dots are missing. Also second
Since a gap 105 is created between the recording head 104 and the ink film 1030, heat cannot be efficiently transferred to the ink under the gap in the thermal transfer type. Since the electrical contact with the layer 95 deteriorates, the ink is not sufficiently melted, resulting in poor transfer.

In order 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.

Since the recording head must have heat resistance, this idea can only be applied to low-speed printing devices with little temperature load.

Particularly, bond paper used for official documents in Europe and the United States cannot be printed due to the above 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 problems]

The printing device of the present invention includes a thermal transfer medium including a heat-melting ink layer whose transfer efficiency has hysteresis characteristics with respect to temperature;
A transfer medium that receives the heat-melting ink, a heating means that selectively heats the entire thermal transfer medium, and a pressurized transfer medium for transferring the thermal transfer medium to the transfer medium. It is composed of a rotating solid elastic body having a hollow portion filled with gas or fluid, and a transfer means consisting of a rotating support that allows rotation of the elastic body, and the heating means is connected to the recording medium by the transfer means. 6 [Operation] According to the above structure of the present invention, first, the temperature of the heat-melting ink in the thermal transfer medium is selectively increased by the heating means, and the viscosity is decreased. etc. to improve transfer efficiency.

Thereafter, the heat-melting ink is pressure-transferred to the transfer medium by the transfer means, but since the transfer efficiency has hysteresis with respect to temperature, even when the ink reaches the transfer means, the temperature decreases. figure.

Since improved transfer efficiency such as reduced viscosity is maintained, the same effect can be obtained even if transfer is performed separately from heating. Furthermore, since the transfer means can be separated positionally from the heating means, flexibility in the configuration of the transfer means is obtained. Therefore, in the present invention, an elastic body having a hollow portion filled with gas or fluid and the elastic body are used as a thermal transfer medium. The transfer means was composed of a rotating support for rotating with the glance movement.

By doing this, when the thermal transfer medium is pressed onto the medium to be transferred by the transfer means, the thermal transfer medium becomes an ultra-thin, extremely soft and highly malleable film of about 10 μm, and the transfer means becomes essentially a "water pillow". The following, which has the effect of
It is possible to sufficiently follow and bring the thermal transfer medium into close contact with the subtle irregularities on the surface of the transfer medium. The "water pillow" effect is when you press it against a surface with bumps that cause a water pillow.

This means that the water pillow concaves and follows the shape, and that, according to Pascal's law, even pressure can be obtained no matter where on the minute part of the pressurizing surface.

Therefore, even a transfer medium with rough smoothness can be printed without deteriorating print quality.

〔Example〕

FIG. 1 is a diagram showing the entire layerer of the 5A embodiment of the present invention, in which 1 is a transfer paper, 63 is an electrically conductive thermal transfer film fed from the transfer paper supply roller 2, and the film supply roller 4, and after undergoing a printing process, is taken up by a film winding roller 5. 6 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 3, as shown in FIG. 2, consists of a polyethylene terephthalate film (PKT) t-substrate N31 having a thickness of 6 μm, a resistance layer 32 on one side of the substrate layer, and an ink layer 35 on the other side. The resistance layer 52 is made by dispersing 20% by weight of carbon powder in a resin. The resistance value is approximately I
It was KQ/-. All ink layers 33 having supercooling characteristics as shown in FIG. 3 were used. When the ink is heated from room temperature, its viscosity decreases and the phase transitions from a solid phase to a liquid phase, as shown by curve 35 in FIG. keep. Reference numeral 7 denotes an energized recording head, which consists of a recording electrode 71 and its support 72, as shown in FIG.

A voltage is applied between the recording electrodes 71 and brought into contact with the current-carrying layer 32 to generate electricity and heat.

8 is a transfer means υ, as shown in the first embodiment in FIG.
A support base 82 for supporting and pressurizing the 1 and 1 elastic bodies 81
And rotation 83! It consists of 7 rotating supports.

Next, FIGS. 6(a) and 6(b) similarly show another embodiment of the transfer means 8, in which a hollow elastic body 86 filled with an elliptical fluid or gas and a hollow elastic body 86 filled with fluid or gas are pressed against each other. It consists of a rotating support body consisting of a group of rollers 84 and a belt 85 for rotation.

Furthermore, FIG. 7 shows yet another embodiment of the transfer means 8, which is based on the example shown in FIG.
- The number of roller groups 84 is increased.

Next, the effects of the above configuration will be described. The energized thermal transfer film 5 fed out from the film supply roller 4 comes into contact with the recording pole 71 at the edge portion of the energized recording head 7 . At this time, since tension is applied in the direction of arrow A by the mechanism 6 that applies tension to the electrically conductive thermal transfer film 5, the resistance layer 62 of the electrically conductive thermal transfer film 5 is strongly pressed against the recording electrode 71. Moreover, the base j-31 of the electrically conductive thermal transfer film 3 is made of polymer resin and has ductility.
Even if the linearity of the etch part is somewhat poor, it follows without any problem.
Therefore, good current conduction is possible between the recording electrode 71 and the resistor 52, and of course it does not depend on the surface condition of the transfer paper 10 at all.

In this way, the ink layer 66 is heated by energization of the resistance layer 62.
Selected portions of are heated and melted. Hereinafter, the process of heating and melting the ink by the recording head will be referred to as the heating process.
The process of transferring the ink 33 onto the transfer paper 1 by the transfer means 8, which will be described later, is referred to as a transfer process.

As mentioned earlier, ink 33 has supercooling characteristics as shown in Fig. 3, so even if there is a delay in step 1 from the heating process and it is cooled to near room temperature by the atmosphere, it maintains its melt viscosity. Therefore, by applying pressure with the transfer means 8, transfer to the transfer paper 1 becomes possible.

Moreover, since the transfer means 8 has the above-mentioned "water pillow effect", even if the transfer paper 1 with rough smoothness is used, the transfer pressure can be applied uniformly, and transfer noise does not increase.

When we actually attempted to print using the configuration of the present invention described above, we were able to print good images only on thermal transfer paper with a Peck smoothness of 200 seconds or more, but on bond paper with a Peck smoothness of 8 seconds or more. Good printing was also possible. Further, when the configuration of the present invention is used, since the ink does not come into contact with the transfer paper during the heating process, the heat does not escape to the transfer paper, so the printing efficiency is improved.

When using the ink used in this example and heating the transfer paper and the electrically conductive thermal transfer film in close contact with each other as in the past, the printing energy was F) 7 mJ per millimeter squared. In the example, it was 4.5 m and T. The printing efficiency was also increased by about 35%.

〔Effect of the invention〕

As described above, 1. According to the present invention, by separating the heating process and the transfer process, the range of selection of mechanisms for the heating method and the transfer method is expanded, and a "water pillow" effect is introduced in the transfer process to 1%. This has the effect that printing on rough surfaces, which has been difficult in the past, can be performed satisfactorily and stably.

However, 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 increase in printing efficiency.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the structure of a stamp device according to the present invention. W! FIG. 2 is a diagram showing an example of the configuration of the electrically conductive thermal transfer film in FIG. 1. FIG. 3 is a diagram showing the characteristics of the ink used in the electrically conductive thermal transfer film of FIG. 2. FIG. 4 is a diagram showing an embodiment of the configuration of the recording head shown in FIG. 1. 5 is a diagram showing details of an embodiment of the transfer means shown in FIG. 1, (a) is a side view of the transfer means, and (b) is a sectional view thereof. FIG. 6 is a diagram showing details of another embodiment of the transfer means in FIG. 1; (a) is a side view showing an example of the transfer means;
(b) is a top view thereof. FIG. 7 is a diagram showing details of yet another embodiment of the transfer means shown in FIG. 1. Broom 8 (a) (1)) are the principles of conventional thermal transfer printing devices, respectively? The cross-sectional views (a) and (b) shown are process drawings. FIG. 9 is a diagram explaining the shortcomings of the conventional thermal transfer printing device. (a) Is the ink transfer defective? In the cross-sectional view shown ((a)(
B) is a process diagram. (b) is a cross-sectional view showing a heat transfer failure in thermal transfer, and (c) is a cross-sectional view showing a current conduction failure in an electric thermal transfer method. 1... Transfer target [transfer target medium] 3... Electric thermal transfer film (thermal transfer medium) 7... Recording head (heating means) 8... Transfer means 33... Ink layer 81... Elasticity Body 86...Elastic body 87...Rotating support body or more

Claims (1)

[Claims] A thermal transfer medium including a hot-melt ink layer whose transfer efficiency has hysteresis with respect to temperature, a transfer medium that receives the hot-melt ink, a heating means for selectively heating the thermal transfer medium, and a thermal transfer medium comprising: A transfer means consisting of a rotating ellipsoid-shaped or donut-shaped elastic body having a hollow portion filled with gas or fluid for pressurized transfer to the transfer medium, and a rotating support for allowing rotation of the elastic body. A printing apparatus characterized in that the heating means is installed before the transfer means in the direction in which the recording medium travels.