JPH02117857A - Thermal head - Google Patents

Abstract

PURPOSE:To make the structure of a thermal head symmetrical at right and left and also make possible printing in one and its opposite directions by forming an electrode section and a flexible cable-connecting section at both ends in a linear direction of the heat generating element of a thermal head, and providing an upper and a lower layer which is an array of individual electrodes and a common electrode respectively with the thermal head. CONSTITUTION:A glaze 5 is provided on a ceramic substrate 1 and a heat generating element 2 is formed on the glaze. In addition, a common electrode 4a is connected to the heat generating element 2 from a right direction, and individual electrodes 4b are connected from a left direction. The common electrode 4a and the individual electrodes 4b are insulated against the other with an insulative layer 6, and a protection layer is formed on the insulative layer. Under this structure, the electrode section is drawn out in two directions, that is, upper and lower directions, and a thermal head can be reduced in size by providing two layers of the common electrode and individual electrodes as an upper and a lower layer. Further, the right and left sides of these layers are symmetrical. Consequently, if a thermal transfer ribbon is used, it is possible to print data in one and its opposite directions.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to thermal in thermal printers [Prior Art] In a conventional thermal head, an electrode section connected to a heating element is connected to a ceramic substrate in one direction. Formed towards the end, and also individually on one side for the heating element row! A common electrode is arranged on the same layer on the opposite side of 4%.

[Problems to be Solved by the Invention] However, in the conventional thermal head, the electrode portions are all formed on the same layer toward one end of the ceramic substrate. Therefore, the size of the ceramic substrate must be wide enough to accommodate the common electrode and the individual electrodes for the number of heating elements, and since the area occupied by these electrodes is large, the size of the ceramic substrate must be thick (because it becomes thick when printing). There is a problem in that pressing the head reduces pressure and has a negative effect on print quality.Also, since a common electrode is formed on one side of the heating element row and individual electrodes are formed on the opposite side, the head is not symmetrical. (When printing using a thermal transfer ribbon, there is a problem that printing can only be done when the ribbon is moving forward, but not when it is returning.

An object of the present invention is to three-dimensionally divide the electrode portion connected to the heating element to reduce the size of the ceramic substrate and to make the structure of the head bilaterally symmetrical to perform bidirectional printing.

[Means for Solving the Problems] In order to solve the above problems, there is a means for forming connection parts between electrode parts and flexible cables at both ends of the heating elements in the row direction of the thermal head, and a means for forming connection parts between electrode parts and flexible cables at both ends of the heating elements in the row direction, and a means for forming individual electrodes for the heating elements. The method is characterized by forming the common electrode layer and the common electrode layer in two layers, upper and lower.

[Effects] By configuring the electrode section as described above, the size of the ceramic substrate can be reduced and the pressing pressure of the head can be increased, improving printing quality. Also, since the head is symmetrical, it is possible to improve printing quality. Bidirectional printing is possible when using a thermal transfer ribbon.

[Example] Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an embodiment of the present invention. Heat generating elements 2 are arranged in a row in the center of a ceramic substrate 1. The individual electrodes 4h connected to the heating elements 2 are wired in the vertical direction of the ceramic substrate 1, and the common electrode 4α is also wired in the vertical direction, and is connected to the electrode connection portions 4C at the upper and lower ends of the ceramic substrate 1.
are connected to F2O3 respectively.

FIG. 2 shows the shape of the common electrode 4a connected to the heating element 2. The wiring is connected to the common electrode 4 alternately on the left and right depending on the order of the heating elements 2.
It is done with α. The common electrode 4a has as wide an area as possible to facilitate current flow.

FIG. 3 shows the shape of the individual electrode 4b connected to the heating element 2. The wiring is connected to the individual electrodes 4 alternately on the left and right depending on the order of the heating elements 2.
It is done with b. At this time, the common electrode 4α and the individual electrode 4b
The wiring direction is opposite to that of the heating element 2. For example, for a given heating element 2, if the common xbaa is connected from the left side, the individual electrodes 4b are connected from the right side. This is to avoid the problem that when two electrodes are connected to the heating element 2 from the same side, the area where they are connected becomes locally thick.The individual electrodes 4b connected to the heating element 2 are The wiring is directed toward the upper and lower ends of the ceramic substrate 1.

FIG. 4 shows the wiring of the FPO5. The common electrode 3α of F'PC5 is connected to the common electrode 4α of the ceramic substrate 1,
The common electrode 3b of PO5 is the common electrode 4 of the ceramic substrate 1.
It is connected to b. At this time, since the individual electrodes 4b of the ceramic substrate 10 are connected to the heating element 2 from the left and right, the heating element 2
Since the individual electrodes 4b are not wired in the vertical direction of not give.

FIG. 5 is a sectional view of the thermal head shown in FIG. 1 with the heating element 2 in the center. A ceramic substrate 1 has a glaze 5 on which a heating element 2 is formed.

Here, the common electrode 4α is connected to the heating element 2 from the right direction, and the individual electrodes 4b are connected from the left direction. The common electrode 4α and the individual electrodes 4b are insulated from each other by an insulating layer 6. A protective layer 7 is formed on these layers.

In this way, by drawing out the electrode portion in two directions (up and down) and forming the common electrode layer and the individual electrode layers in the upper and lower layers, the head can be made smaller (and also laterally symmetrical).

[Effects of the invention] According to the present invention, the head can be made bilaterally symmetrical, so bidirectional printing using a thermal transfer ribbon is possible, and the head is small, so the contact area with the printing paper is small (the pressing of the head is done by pressure). The head is thicker, which improves print quality. Furthermore, the head is smaller, which reduces costs.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of one embodiment of the invention. FIG. 2 is a schematic diagram of the shape of the common electrode portion of the head. FIG. 3 is a schematic diagram of the shape of the individual electrode portion of the head. Figure 4 is a schematic diagram of IPPC. FIG. 5 is a sectional view of the head. 1... Ceramic substrate 2...Heating element 3・・・・・・・・・FP　C α・・・Common electrode part of the head b...Individual electrode part of the head C... Electrode connection part ・・・・・・・・・Glaze ・・・・・・・・・Insulating layer ・・・・・・・・・Protective layer Below Up

Claims (1)

[Claims] A thermal head having a heating element arranged in a row on a heat-resistant insulating substrate such as a ceramic, an electrode part consisting of a common electrode layer and an individual electrode layer connected to the heating element, and a flexible cable connected to the electrode part. means for forming connection parts between the electrode part and the flexible cable at both ends of the heating element of the thermal head in the column direction;
A thermal head comprising means for dividing the common electrode layer and the individual electrode layer of the electrode section into an upper layer and a lower layer.