JPS6349449A - Thermal head - Google Patents

Abstract

PURPOSE:To enable high-speed recording in high quality and elimination of ink ribbon cut by providing dummy glazed parts which are shorter than glazed parts by prearranged length and without an electricity/heat converter on both sides of a plurality of glazed parts. CONSTITUTION:Glazed parts (dot-formed parts) 38, 38 having a plurality of electricity/heat converters 33 are provided in plurality rows (double) at a prearranged interval in a scan direction indicated by an arrow on the surface of a substrate 31 which is composed of plates such as ceramic. In addition, dummy glazed parts 39, 39 having no electricity/heat converter are provided on both sides of the glazed parts. The height (h) of the dummy glazed parts 39, 39 is made less than that of the glazed parts for recording 38, 38 by prearranged length. Thus the head is of a plural row type and capable of improve recording speed, and at the same time, it provides high-quality recorded matter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a recording head used in a serial type thermal recording device, and in particular, the present invention relates to a recording head used in a serial type thermal recording device, and in particular, it has a plurality of glaze portions, and each glaze portion is provided with an electrothermal converter (heating element). etc.) related to a multi-row type thermal head arranged in an array.

[Conventional technology]

As a recording device for printers, plastics, etc., a recording head is supported so as to be able to reciprocate along a platen, and a sheet (recording medium such as paper or a thin plastic plate) banked up on the platen is mainly scanned by the recording head. (Serial type is widely used.

Furthermore, various recording methods are used, such as an inkjet method, a wire dot method, and a thermal method.

Furthermore, thermal recording devices use a thermal transfer type that uses a regular sheet and drives a recording head (thermal head) that is pressed into contact with an ink ribbon to apply molten ink to record, and a thermal recording device that uses a heat-sensitive sheet. However, there is a thermal type that records while being directly heated with a thermal head.

The present invention is applicable to a recording head (thermal head) used in a serial type thermal recording apparatus.

This type of thermal head usually uses a plurality of (for example, 24 or 32) electrothermal transducers such as heating resistors in a vertical line.
Single-row thermal heads arranged in rows are used.

In addition, in a thermal head, if heat pulses are continuously applied, the electrothermal converter heats up, reducing durability and greatly reducing print quality. Therefore, cooling time is provided between each drive interval. Alternatively, heating is prevented by reducing the recording speed.

By the way, in a single-row type thermal head in which electrothermal transducers are arranged in a single row, the drive (heat) interval is naturally restricted to prevent heating, and it is difficult to improve the recording speed.

Therefore, as an advantageous structure to improve the recording speed,
A multi-row thermal head has been proposed in which a plurality of heat-resistant glass glaze portions are formed at predetermined intervals in the main scanning direction and electrothermal converters are arranged in each glaze portion.

For example, when a group of electrothermal transducers are arranged in two rows, if these two rows are driven simultaneously, it is possible to form twice as many dots per head position (scanning position) as in the case of a single row type. Therefore, it is possible to achieve a recording speed twice that of a single row type head.

However, the conventional multi-row type thermal recorder has a disadvantage in that the recording quality is inferior to that of the single-row type. The reason is as follows.

In the case of a single-row type head, as shown in the cross-sectional view of FIG. Since the stripping angle α is set to be sufficiently large, the recording quality is maintained at a high level.

On the other hand, in the case of a multi-row (two-row) type thermal head, as shown in the cross section of FIG. Therefore, the ink ribbon stripping angle α is set smaller than that of the single row type shown in FIG. 5, and this! Since the ripping angle f', +1 is not constant, the recording quality deteriorates.

Furthermore, as shown in FIGS. 5 and 6, a common drawback of the conventional single-row type and multi-row type is that the ink ribbon 5 and the edge of the substrate 1 come into contact and rub against each other directly. Another drawback was that it was easy to cut.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal head which can solve the problems of the prior art, which can perform high-speed recording, improve recording quality, and eliminate the problem of cutting the ink ribbon.

[Means to achieve the purpose]

The present invention provides a multi-row thermal head in which electrothermal transducers are arranged in each of a plurality of glaze parts, in which a height is lower than the glaze part by a predetermined dimension on both sides of the plurality of glaze parts. The above object is achieved by providing a dummy glaze portion that does not have an electrothermal converter.

〔Example〕

The present invention will be specifically described below with reference to FIGS. 1 to 4.

FIG. 4 illustrates a thermal recording device equipped with a thermal head according to the present invention.

In FIG. 4, a thermal head 14 mounted on a carriage 13 is configured to record on a sheet 12 that has been subjected to buffing on a platen 11. Note that the illustrated platen 11 has a roller shape and also serves as a sheet feeding roller.

The carriage 13 is movably mounted along a guide shaft 15 installed parallel to the platen 11, and is wound around a stamping motor 16, a driving pulley 17, a driven pulley 18, and these pulleys, and a single force is applied to the carriage 13. It is reciprocated by a drive system consisting of a timing bellet 19 that is fitted together.

The thermal head 14 is mounted so as to be driven to swing between a down position where it is in pressure contact with the sheet 12 and an amplifier position where it is separated.

A ribbon cassette 20 is detachably mounted on the carriage 13 for feeding an ink ribbon to the front surface of the thermal head 14, that is, to the printing surface having dont forming means.

During recording, the ink ribbon in the ribbon cartridge 20 is wound and driven in synchronization with the movement (main scanning) of the thermal head 14 by a ribbon roller (not shown) provided on the carriage 13.

FIG. 1 shows a cross-sectional view of one embodiment of a thermal head 14 according to the present invention, and FIG. 2 shows a main part of the front side of FIG. 1.

1 and 2, a plurality of (in the illustrated example, two (solid) glaze layers 32, 32, are formed, and a plurality of layers of electrothermal transducers such as heating resistors are formed on the surface of each glaze layer.

The glaze layer 32.32 is formed of, for example, a heat-resistant glass layer.

Dummy glaze layers 34, 34 having no electrothermal converter are formed on both sides of the two glaze layers 32, 32. In the illustrated example, the dummy glaze layer 34.3
4 are formed along both side edges of the substrate 31, respectively.

After forming a conductive layer over almost the entire surface covering the layer of the electrothermal converter 33.33 and the surface of the substrate 31 including the dummy glaze layer 34.34, each glaze layer is formed by patterning the conductive layer. Common electrode 35 and individual electrodes 36.3 of electrothermal transducer 33.33 on 32.32
6 is formed.

From above, i.e. pattern electrodes 35, 36, 36
A protective film 37 is formed over almost the entire surface including the electrothermal transducers (heating resistors, etc.) 33, 33 that are not covered by the electrodes, that is, the heat generating portion. This protective film 37 is formed of, for example, an insulating layer made of heat-resistant and abrasion-resistant glass material.

In this way, the substrate 31 is provided with a plurality of rows (two rows) of glaze portions (dot forming portions) 38, 38 having a plurality of electrothermal transducers 33 at predetermined intervals in the scanning direction, and further,
Dummy glaze portions 39 and 39 having no electrothermal converter are provided on both sides of these glaze portions 38 and 38.

However, the height h of the dummy glaze portion 39.39 is lower than the height H of the recording glaze portion 38.38 by a predetermined dimension.

FIG. 3 is a plan view of the thermal head 14 according to the present invention installed in a recording apparatus.

As is clear from FIG. 3, according to the multi-row thermal head 14 described above, the recording glaze portion 38
．． Since the dummy glaze portions 39 and 39 are provided on both sides of the ink ribbon 38 and adjacent to the edge thereof, the peeling angle α of the ink ribbon 40, that is, the angle at which the ink ribbon separates from the sheet 12 after recording, can be made larger than in the conventional structure. Since the settings can be adjusted, it is now possible to obtain sharp and excellent recording quality.

Further, since the dummy glaze portion 39 is in contact with the ink ribbon 40 at a position away from the sheet 12 or near it, the ink ribbon after recording can always be peeled off at the same position and at the same peeling angle α. Stable, high-quality recordings were obtained.

Furthermore, according to the thermal head 14 shown in FIGS. 1 to 3, the ink ribbon 40 is coated with a dummy glaze 39.39 having a much smoother surface than the substrate 31 made of ceramic or the like.
Since the ink ribbon 40 is brought into contact with the curved surface of the ink ribbon 40, the running of the ink ribbon 40 becomes smooth, and damage and cutting can be reliably prevented.

Note that the height h of the dummy glaze portion 39.39 is set lower than the height H of the recording glaze portion 38.38 by an appropriate dimension, so there is no decrease in force when pressing the ink ribbon with the glaze portion 38.38. Electrothermal converter in glaze part 33.33
can be brought into close contact with the ink ribbon 40 and the sheet 12 with sufficient pressure, and the heat from the electrothermal transducers 33 and 33 can be efficiently transferred to the ink ribbon 40, thereby improving recording density and recording quality. Ta.

Although the present invention has been described above by exemplifying the case where the present invention is applied to the two-row thermal head 14, the present invention can be similarly applied to a thermal head having three or more rows of recording glaze portions.

〔effect〕

As is clear from the above description, according to the present invention, dummy glaze parts are provided on both sides of a plurality of glaze parts, which are lower in height by a predetermined dimension than the glaze parts and do not have an electrothermal converter. Therefore, it is possible to obtain a thermal head that can improve the recording speed by using a multi-row head, and at the same time obtain excellent recording quality, and also eliminate the possibility of cutting the ink ribbon due to contact with the end of the head.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an embodiment of the thermal head according to the present invention, FIG. 2 is a partial front view of the thermal head of FIG. 1,
FIG. 3 is a plan view of the thermal head shown in FIG. 1 attached to a recording device, FIG. 4 is a schematic perspective view of the thermal recording device, and FIG. 5 is a cross-sectional view of a conventional single-row thermal head. , FIG. 6 is a cross-sectional view of a conventional multiple-type thermal head. 14...--Thermal head, 31--
--- Substrate, 33 --- Electrothermal converter (heating resistor, etc.), 38 --- Glaze section (for recording), 39-・・−・−Dummy glaze part, H−・−・−・−Height of glaze portion, h・−・−−
-1- Height of dummy glaze part.

Claims (1)

[Claims] (1) In a multi-row thermal head in which electrothermal converters are arranged in each of a plurality of glaze parts, an electric A thermal head that includes a dummy glaze section that does not have a heat converter.