JPH03190759A - Thermal transfer printer - Google Patents

Abstract

PURPOSE:To make the state of contact of a thermal bead with an ink sheet stable and uniform and decrease the occurrence of uneven concentration to obtain a high picture quality by providing a thermal head or the substrate of the thermal head with a vibrating member and by vibrating the thermal head. CONSTITUTION:When a vibrating member (piezoelectric element) 3 is made to vibrate, the vibration is transmitted to a thermal head 1 so that the thermal head 1 and an ink sheet 5 are biased while vibrating finely. Thus, the heating element 4 of the thermal head 1 and the ink sheet 5 can keep the stable state of contact so that it is possible to obtain a printing quality characterized by very little uneven concentration and by high picture quality.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal transfer printer using a sublimation type or melting type thermal head.

[Summary of the invention]

As the image quality and density of thermal transfer printers has increased, various methods have been tried based on the shape of the heat generating part of the thermal head and the pressing force of the platen roll, but thermal transfer printers satisfy both print quality and reliability of the thermal head. The present invention improves the contact between the heat generating part of the thermal head and the ink sheet by providing a vibrating member on the thermal head or the support of the thermal head to vibrate the thermal head. To provide a thermal transfer printer with good printing quality and high reliability of the thermal head by improving the sliding condition between the ink sheet and the thermal head.

[Conventional technology]

Conventional thermal transfer printers have a structure in which the thermal transfer roller is directly attached to a support member and pressed against a platen consisting of a drum, rubber roller, etc. An ink sheet and image receiving paper are sandwiched between the thermal head and the platen, and when the heat generating part of the thermal head generates heat, the ink sheet is heated, and the dye is transferred to the image receiving paper by sublimation or melting. .

[Problem to be solved by the invention]

Conventional thermal transfer printers like the ones mentioned above are good when the pixel density is low or when the density unevenness is allowed to some extent, but when it comes to eliminating density unevenness and focusing on gradation like dye-sublimation printers, The reality is that it cannot be applied to high-grade cases where the pixel density is high. The reason for this is that in order to improve printing quality, it is necessary to improve the contact state between the thermal head and the ink sheet, and as a means of achieving this, it is necessary to increase the pressing force between the heat generating part of the thermal head and the platen. Partially glazed thermal heads are used because they can locally increase the pressing force.

However, if you try to improve the printing quality by increasing this pressing force, the friction between the thermal head and the ink sheet will increase, the stress near the heat generating part of the thermal head will increase, and the heat generating part will be destroyed early. It was extremely unreliable and significantly shortened the life of the thermal head. Furthermore, dust, which was not a problem when the pressing force was low, can destroy the heat generating part of the thermal head when the pressing force is high.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention has a configuration in which a vibrating member is provided on the thermal head or the support of the thermal head to vibrate the thermal head in order to achieve both high image quality and high reliability.

(Function) In the above configuration, when the vibrating member is vibrated, the vibration is transmitted to the thermal head, and the thermal head and ink sheet are pressed while vibrating finely. It is possible to maintain a stable contact state, and it is possible to obtain high-quality printing with extremely small density unevenness.Moreover, since the thermal head and ink sheet are in contact with each other through vibration, it is possible to maintain a stable contact state with the same pressing force. Since the slippage is improved, the coefficient of friction is also reduced, and the stress applied to the heat-generating part of the thermal head is greatly reduced.Furthermore, dust is discharged smoothly, ensuring the reliability of the thermal head.

〔Example〕

The present invention will be described below with reference to drawings of embodiments.

FIG. 1 is a side view of the configuration around a thermal head when a piezoelectric element is used as an example of a vibrating member.

The thermal head 1 is fixed to a support 2, and a piezoelectric element 3 is clamped and fixed thereto. The thermal head 1 may be a commonly used one, and consists of a glaze layer provided on an alumina substrate, electrodes, a resistive layer, and a surface protector 1ffJi. The support body 2 is made of an aluminum plate or the like, and plays the role of fixing the thermal head 1 and radiating heat.

The heat generating section 4 of the thermal head 1 is pressed against a platen roll 7 via an ink sheet 5 and an image receiving paper 6. The structure and operation of these printers are exactly the same as those of conventional thermal transfer printers, except for the piezoelectric element 3 used as a vibrating member.

Here, the piezoelectric element 3 can be made of a known material such as barium titanate, and electrodes are provided on both sides.
They are connected to terminals 8a and 8b, respectively. When an AC voltage is applied to these terminals 8a and 8b, the piezoelectric element 3 vibrates, and the vibration is transmitted to the thermal head 1, causing the thermal head 1 to vibrate. Various vibration modes such as thickness longitudinal vibration and thickness rotation vibration can be applied, and the vibration frequency is preferably ultrasonic vibration such as 40) lz.

Although this vibration of the thermal head 1 is a minute vibration,
The contact state with the ink sheet 5 is stabilized and uniformized, and the coefficient of friction is also reduced, and the stress applied to the heat generating part 4 of the thermal head 1 is significantly reduced. It is also possible to remove dirt and grime without applying great stress to the heat generating part 4.

As the thermal head 1 vibrates in this way, it is in good contact with the ink sheet 5, which reduces adverse effects such as density unevenness, resulting in high image quality.In addition, there is less stress and damage to the heat generating part 4, so the thermal head 1 has a long lifespan. can be kept for a long time.

Next, the present invention will be described with reference to other embodiments. FIG. 2 shows an example in which an electromagnetic vibrating section is used as the vibrating member. Thermal Rad 1. Support body 22 heat generating part 4. Ink sheet 5. Receiving paper6. The platen roll 7 is completely the same as the conventional example. However, a magnet pin 9 made of a magnet is erected on the support 2, and a coil 10 is provided so as to surround this magnet pin 9. The magnet bottle 9 and the coil 10 constitute an electromagnetic vibration section. By passing an alternating current through the terminals 11a and llb of the coil 10, the magnet pin 9 vibrates, and the thermal head l vibrates via the support 2. The coil IO only needs to be fixed to an external immovable member. The operation of this embodiment is exactly the same as that described for the embodiment of FIG.

In addition to the piezoelectric element shown in Fig. 1 and the electromagnetic vibrating part shown in Fig. 2, the vibrating member may be simply mechanically vibrated, and the vibration frequency may be arbitrary, but It is convenient because there is no noise. Also, although the explanation was given using a platen roll as the platen in both Figures 1 and 2,
It is not limited to a platen roll, and may be of a drum type.

〔Effect of the invention〕

As described above, according to the present invention, by providing a vibrating member to vibrate the thermal head,
Since the contact state between the thermal nozzle and the ink sheet is stable and uniform, density unevenness is reduced and high image quality is achieved, so a thermal transfer printer with high image quality can be configured even with a high-density thermal head. In particular, stable image quality can be obtained even when gradation is important, such as with sublimation thermal transfer printers.Furthermore, since the thermal head vibrates, there is less friction between the thermal head and the ink sheet. In addition, since dust can pass through smoothly, stress and damage to the heat generating part of the thermal head are significantly reduced, extending the life of the thermal head. As described above, according to the present invention, it is possible to provide a thermal transfer printer that satisfies both high image quality and reliability that could not be achieved conventionally, and the effects thereof are extremely large.

[Brief explanation of drawings]

FIG. 1 is a side view showing the structure around a thermal head when a piezoelectric element is used as a vibration member in a thermal transfer printer according to an embodiment of the present invention, and FIG. 2 is an electromagnetic FIG. 3 is a side view showing the structure around the thermal head when a vibrating section is used. ■ ・ ・ 2 ・ ・ 3 ・ ・ ・ 4 ・ ・ ・ 5 ・ ・ 6 ・ ・ 7 ・ 8 ・ ・ 9 ・ ・ 10 ・ ・ 11 ・ ・ Thermal head support Piezoelectric element heating part Ink sheet Receiving paper platen roll terminal Magnet pin coil terminal Figure 1 and above

Claims (1)

[Claims] A thermal transfer printer using a thermal head, characterized in that a vibration member is provided on the thermal head or a support for the thermal head to vibrate the thermal head.