JP2524104B2 - Printing equipment - Google Patents

Description

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

[Prior Art] As shown in FIG. 8A, the thermal transfer recording method is such that the heat-meltable ink 91 applied to the film-shaped substrate 90 is selectively heated and melted by a thermal head having an electric heating element 92. This is a printing method in which the ink 91 is pressed against the transfer target 93 and transferred under pressure to obtain an image.

Further, FIG. 8b is a view for explaining an energization heat transfer system which is a modification of the above-mentioned heat transfer system, in which the heat-melting ink 91 is formed on one surface of the film-shaped substrate 90 and the electricity generation layer 95 is formed on the other surface.
And an ink film having a recording head and a recording head having a recording electrode 96 for supplying a current to the electric heating layer 95. Each recording method has the features that silent printing is possible, pigment-based ink can be used, high density printing is possible, colorization is easy, the recording head line is easy, and high speed printing is possible.

[Problems to be solved by the invention]

However, the above-mentioned conventional example has a problem in that although a good print can be obtained for a print having a smooth surface, a good print cannot be obtained for a print having a rough surface. Was.

The cause will be described with reference to FIGS. 9 (a), (b) and (c). First, the heated and melted ink 101 is the transfer target 9
Since there is no contact in the concave portion 102 of 3, there is a dot dropout. The second
Since a gap 105 is formed between the recording head 104 and the ink film 103, heat is not efficiently transferred to the ink under the gap in the case of the thermal transfer system. Since the electrical contact with the layer 95 is aggravated, the inks are not sufficiently melted to cause transfer failure.

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 because of the above reasons, which is a factor that prevents the spread of the thermal transfer method.

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

[Means for solving problems]

The printing apparatus of the present invention includes a thermal transfer medium that includes a hot-melt ink layer having a transfer efficiency having a hilterisis characteristic with respect to temperature, a transfer medium that receives the hot-melt ink, and heating that selectively heats the thermal transfer medium. Means, an ellipsoidal elastic body having a hollow portion filled with a gas or a fluid for pressure-transferring the thermal transfer medium to the transfer medium, and a rotary support for allowing the elastic body to rotate. A transfer means, and the heating means is installed on the front side of the transfer means in the recording medium advancing direction.

[Action]

According to the above configuration of the present invention, first, the temperature of the hot-melt ink in the thermal transfer medium is selectively raised by the heating means to improve the transfer efficiency such as decrease in viscosity. After that, the transfer means transfers the hot-melt ink to the transfer medium under pressure. However, since the transfer efficiency has a hysteresis with respect to the temperature, the temperature is lowered even when the transfer means is reached. Nevertheless, since the improved state of the transfer efficiency such as the decrease of the viscosity is maintained, the same effect can be obtained even if the transfer is performed separately from the heating. Further, since the transfer means can be separated from the heating means in a positional manner, the degree of freedom of the constitution of the transfer means can be obtained. Therefore, in the present invention, an elastic body having a hollow portion filled with a gas or a fluid and the elastic body of the thermal transfer medium are provided. The transfer means is composed of a rotary support for rotating along with the special motion.

By doing so, when the thermal transfer medium is pressed against the transfer target medium by the transfer means, the thermal transfer medium is an extremely thin film having a very soft malleability of about 10 μm, and the transfer means is substantially a “water pillow”. Has the effect of
The thermal transfer medium can be sufficiently followed and adhered to the subtle unevenness of the surface of the transfer medium. The "water pillow" effect is that when the water pillow is pressed against a certain uneven surface, the shape of the water pillow causes the water pillow to dent and follow it. This means that a uniform pressure can be obtained. Therefore, it is possible to print on a transfer medium having a rough smoothness without deteriorating the print quality.

〔Example〕

FIG. 1 is a diagram showing an overall layout of an embodiment of the present invention, in which 1 is a transfer paper, which is supplied from a transfer paper supply roller 2. An electrothermal transfer film 3 is fed from a film supply roller 4 and is taken up by a film take-up roller 5 after a printing process. 6 is a mechanism for applying tension to the electrothermal transfer film in the direction of arrow A. As shown in FIG. 2, the electrothermal transfer film 3 has a structure in which a polyethylene terephthalate film (PET) having a thickness of 6 μm is used as a base layer 31, and one of the base layers is coated with a resistance layer 32 and the other is coated with an ink layer 33. The resistance layer 32 is made by dispersing 20% by weight of carbon powder in resin. The resistance value was about 1 KΩ / cm ² . The ink layer 33 used has a supercooling characteristic as shown in FIG. When the ink is heated from room temperature, the viscosity decreases as shown by the curve 35 in FIG. 3 and the phase transitions from the solid phase to the liquid phase, but even if the ink is cooled to room temperature thereafter, the liquid phase remains for a certain time as shown by the curve 36. keep. 7 is a recording head for electricity,
As shown in FIG. 4, it comprises a recording electrode 71 and its support 72.

A voltage is applied between the recording electrodes 71, and the energization layer 32 is brought into contact with the recording electrodes 71 to generate energization and heat.

Reference numeral 8 denotes a transfer means, as shown in the first embodiment in FIGS. 5 (a) and 5 (b), a tire tube-shaped elastic body 81 made of a 20 .mu.m thick silicone rubber filled with a liquid, and an elastic body. It is composed of a support base 82 for supporting and pressurizing the body 81 and a rotary support composed of a rotation 83.

Next, FIGS. 6 (a) and 6 (b) show another embodiment of the transfer means 8 as well, which comprises a hollow elastic body 86 filled with a rotating elliptical fluid or gas, and pressing it. It is composed of a rotation support member composed of a roller group 84 for rotating and a belt 85.

Further, FIG. 7 shows another embodiment of the transfer means 8, in which the belt 85 is removed from the embodiment shown in FIG. 6 and the number of roller groups 84 is increased.

Next, the operation of the above configuration will be described. The electrothermal transfer film 3 delivered from the film supply roller 4 contacts the recording electrode 71 at the edge of the electrographic recording head 7. At this time, tension is applied in the direction of arrow A by the mechanism 6 for applying tension to the electrothermal transfer film 3 described above, so that the resistance layer 32 of the electrothermal transfer film 3 is strongly pressed against the recording electrode 71. In addition, since the substrate layer 31 of the electro-thermal transfer film 3 is a polymer resin film and has ductility, it can be followed without any problem even if the linearity of the edge portion of the recording head 7 is somewhat poor. Therefore, it becomes possible to carry out good electric conduction between the recording electrode 71 and the resistance layer 32,
Further, as a matter of course, it does not depend on the surface condition of the transfer paper 1. In this way, the selected portion of the ink layer 33 is heated and melted by the heat generated by the electric conduction of the resistance layer 32. Hereinafter, the process of heating and melting the ink by the above-described recording head is referred to as a heating process, and the process of transferring the ink 33 to the transfer paper 1 by the transfer unit 8 described later is referred to as a transfer process.

Since the ink 33 has the supercooling characteristic as shown in FIG. 3 as described above, there is a time lag between the heating process and the process, and the melt viscosity is maintained even when cooled to near room temperature by the atmosphere. Therefore, transfer to the transfer paper 1 is possible by applying pressure by the transfer means 8.

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

When an attempt was made to actually print with the above-described structure of the present invention, the conventional printing was successful only for thermal transfer dedicated paper having a smoothness of 200 seconds or more, but even for bond paper having a smoothing smoothness of 8 seconds. Good printing was possible. Further, when the constitution of the present invention is used, since the ink is not in contact with the transfer target paper during the heating process, heat cannot escape to the transfer target paper, thus improving the printing efficiency. When the ink used in this example was heated in a state in which the transfer paper and the electrothermal transfer film were brought into close contact with each other in the same manner as in the conventional case, the printing energy was 7 mJ per millimeter square meter and was 4.5 in this example. It was mJ. Printing efficiency is 3
It improved by 5%.

〔The invention's effect〕

As described above, according to the present invention, by separating the heating process and the transfer process, the range of selection of the mechanism of the heating method and the transfer method is widened, and in particular, by introducing the “water pillow” effect in the transfer process, It has an effect that printing on a rough surface, which is difficult, can be performed satisfactorily and stably.

In addition, since the ink and the transfer target are not brought into contact with each other during the heating process, the applied heat does not diffuse to the transfer target, so that the printing efficiency is greatly improved.

[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 showing an embodiment of the constitution of the electrothermal transfer film in FIG. FIG. 3 is a diagram showing the characteristics of the ink used in the electrothermal transfer film of FIG. FIG. 4 is a diagram showing an embodiment of the structure of the recording head of FIG. 5A and 5B are diagrams showing details of an embodiment of the transfer means shown in FIG. 1, in which FIG. 5A is a side view showing the transfer means, and FIG. FIG. 6 is a view showing details of another embodiment of the transfer means of FIG. 1, and FIG. 6 (a) is a side view showing an example of the transfer means.
(B) is the top view. FIG. 7 is a view showing details of still another embodiment of the transfer means shown in FIG. 8A and 8B are sectional views showing the principle of the conventional thermal transfer printing apparatus, and FIGS. 8A and 8B are process drawings. FIG. 9 is a diagram for explaining the defects of the conventional thermal transfer printing apparatus, and FIG. 9A is a sectional view showing defective ink transfer.
(B) is a process drawing, (b) is a sectional view showing a heat transfer failure in thermal transfer, and (c) is a sectional view showing a current transfer failure in an electric heat transfer method. 1 ... Transferred paper (transferred medium) 3 ... Electric heat transfer film (thermal transfer medium) 7 ... Recording head (heating means) 8 ... Transfer means 33 ... Ink layer 81 ... Elastic body 86 ... Elastic body 87 ... Rotary support

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-187568 (JP, A) JP-A-62-90265 (JP, A) Actually opened 59-134552 (JP, U) Actually opened 61- 168946 (JP, U)

Claims (1)

(57) [Claims] 1. A thermal transfer medium including a hot-melt ink layer having a transfer efficiency having a hysteresis characteristic with respect to temperature, a transfer medium receiving the heat-melt ink, and a heating means for selectively heating the thermal transfer medium. A rotating ellipsoidal or doughnut-shaped elastic body having a hollow portion filled with a gas or a fluid for pressure-transferring the thermal transfer medium to the transferred medium, and a rotary support allowing the elastic body to rotate. And a transfer unit, wherein the heating unit is installed in front of the transfer unit in the recording medium traveling direction.