JPS5917953B2 - thermal head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a single-row, multi-dot thermal head comprising fine heating elements, and particularly to a thermal head with high resolution.

Single-row multi-dot type thermal heads are usually connected to a matrix circuit on the head to facilitate connection with external circuits.

Figure 1 shows an example of a wiring connection, where 1 is a heating element, 2 is an element (diode) to prevent current from flowing in, 3 is a selector terminal, 4 is a driver terminal, and 5 is a multilayer wiring section. , 6 is a signal feed line, and each heating element is connected to the feed line through a diode. 00 The vertical wiring from each heating element to the selector terminal 3 and the horizontal signal feed line 6 intersect as shown. Therefore, multilayer wiring is used to prevent short circuits, with the former being placed on the same board as the heating element, and the latter being placed on a separate board.

The wiring on the two substrates is connected by thermocompression bonding 5 to form a multilayer wiring section.

However, in the structure shown in FIG. 1, the number of lead wire connection points in the multilayer wiring section 5 is equal to the number of heating elements.
The number of steps involved is large, and the manufacturing yield is also greatly reduced. 'o Figure 2 shows a conventional thermal printer which eliminates the above-mentioned drawbacks, in which the heating element 11 and the heating element 24 are connected through two diodes d71 and d24.

Similarly, heating elements 12 and 23 are connected through diodes d12 and d23. The same applies below. 5 like this
Since it is a wiring, the number of intersection points P between the signal feed line 6 and the board wiring in the multilayer wiring section 5 is half the number of heat generation, and the number of man-hours etc. is greatly reduced. FIG. 3 is an example embodying the wiring shown in FIG. 2, and 21, 22, 23, . . . , 26 are active element arrays. 51, 52, 53, . . . are insulating substrates for multilayer wiring, and 611, 612, 613, 614 are insulating substrates 5.
The lead wires 621, 622, . . . , 624 above 1 are lead wires on the insulating substrate 52, and are similar to the signal feed wires 6 in FIG.
Configure.

This structure is relatively easy to manufacture when the heating element pitch is large. The bonding length D shown in FIG. 3 is a little less than 400 pm in a head with a resolution of 5 dots/Mm.
At 10 dots/Mm, it becomes slightly less than 200 μm and at 20 dots/Mm
For a heavy resolution head, it is less than 100 ttm.

Plate 5 on which lead wires 611, 612, ... 614 are mounted
1 to a pattern on a substrate as shown in FIG. 3 (for example, by thermocompression bonding), a bonding length D of 200 μm is required. Therefore, in the structure of FIGS. 2 and 3, 10 dots/M
It is not possible to produce an ultra-high resolution head with a resolution higher than m. Therefore, the present invention aims to improve the above-mentioned drawbacks of the conventional technology, and its purpose is to provide a thermal head having a structure in which the number of connection points in the multilayer wiring section is small and the bonding length D can be large even when the density of the heating element is high. It is about providing.

A feature of the thermal head according to the present invention is that a plurality of heating elements for printing in a single row multi-dot system are arranged in a row on an insulating substrate, and each n heating element is connected to m blocks (M, n
is a natural number), one end of the heating element of each block is commonly connected to the first external terminal,
The other end of the heating element is connected to the second external terminal, with one heating element for each block being connected in common, and the heating element is connected to the second external terminal by a voltage selectively applied between the first external terminal and the second external terminal. In a thermal head in which a selected heating element generates heat, a connection structure between the second external terminal and the other end of the heating element is formed on the board from each heating element in mutually opposite directions for each adjacent block. A first lead wire is used to form every other pair of the i-th block and the (1+2)-th block (i is a natural number smaller than m-1), and in each of the pairs, each block is 1 sequentially from both ends of
The heating elements of the selected pairs are connected one by one on the same plane, and the N
The thermal printer has second lead wires for a set of books, and means for connecting the corresponding second lead wires of each block via another board. Examples will be described below with reference to the drawings. FIG. 4 shows a wiring diagram of one embodiment of a thermal printer according to the present invention, and FIG. 5 shows a pattern of a thermal printer that realizes FIG. 4.

In Fig. 4, 601', 602', 603', 60
4' is a signal feed line that functions similarly to 601, 602, 603, and 604. In Figures 4 and 5, four heating elements each constitute a block, and from the left of the figure, the first, third,
5th block signal feed line 601, 602, 603, 6
04 is provided at the top of the figure, and signal feed lines 601', 602', 603', 60 of the second, fourth, and sixth blocks are provided.
4' is provided at the bottom of the figure. Generally, the heating elements of the i-th block and the (1+2)th block are connected on the board via diodes. This connection is made by a first lead wire, indicated by A in FIG. 4, which is perpendicular to the arrangement line of the heating elements, and a 21st lead wire, indicated by B in the figure, which is perpendicular to this. Lead wires 614, 613,...6
11 mounted on the insulating plate 51 and lead wires 621, 622,
The insulating plate 52 on which 623 and 624 are mounted is the heating element row 11
Opposite side across 1,112,... (top and bottom of the diagram)
The former connects the second lead wires of the first and third blocks and the second lead wires of the fifth and seventh blocks by multilayer wiring, and the latter connects the second lead wires of the second and fourth blocks. The line and the second lead wires of the sixth and eighth blocks are connected by multilayer wiring.

Common power supply lines 41, 43, 45, . . . and 42, 44, 46, .
13,... will be installed on the opposite side. Because of this configuration, the lead wires 611, 612, 613,
The distance D that allows bonding of ... is the distance of one heat generating element row.

Usually, one block contains 32 heating elements, or twice that number, or half that number. Therefore, even in the case of a resolution of 20 dots/Mm, the length of one block is 1.6 mm (assuming 32 heating elements are included in one block), and a sufficiently reliable connection (bonding) can be achieved. Also, as the resolution increases, the lead wire pitch from the heating element becomes finer and the width becomes narrower, but if the wiring method shown in Figure 5 is used, the signal wire 61
The lead line width of the portion connecting 1, 612, 614, 621, . . . 624 can be made sufficiently thick. In the description of the present invention 1
Although the number of heat generating elements in the block is set to four, it is natural that there is no limit to this number, and there is also no limit to the number of blocks.

A protective film is applied to the heating element and its vicinity, but this is omitted for the sake of simplicity. In the case of a thin film thermal head,
The lead wire from the heating element is made of Au or Cu, etc., and is 0.5 to 2.
The thickness is about μm. For thin films, pattern widths as fine as about 10 μm are possible. For the insulating plates 51, 52, 53, . . . in FIGS. 3 and 5, polyimide films or glass plates having a thickness of about 100 to 3001 tm are used.

Lead wires 611, 612, ... 614, 621, ...
・634... is made of Au or Cu with a thickness of about 5 to 20 pm and is thermocompression bonded or soldered to the pattern on the substrate.
In recent years, single-row multi-dot type thermal heads have begun to use IC active element arrays that combine thyristors with memory capacity and logic circuits consisting of diodes and resistors.

In this case, there is no essential difference in the mounting method of the head except that the number of tangential lead wires between the active element arrays and the number of connection lines between the active element array and the external circuit are slightly increased. As explained in detail above, according to the present invention, the corresponding heating element of the next block is connected on the board, and
Since the wiring direction is reversed for each block, it is possible to increase the bonding length D in the multilayer wiring section, which allows for sufficiently reliable connections (bonding) and improves the mounting density (resolution) of the heating element. I can do it. For example, it becomes possible to realize a thermal head with a resolution of 10 dots/mark or more, which was previously impossible.

[Brief explanation of drawings]

Fig. 1 is an example of a conventional thermal head connection, Fig. 2 is an example of another conventional thermal head connection, Fig. 3 is an example of a pattern that realizes the connection shown in Fig. 2, and Fig. 4 is an example of the present invention. FIG. 5 is an example of a pattern for realizing the connection shown in FIG. 4. 111,112,113,...121,122...
...Heating element, 211, 212, 213, 214, 22
1... Active element, 21, 22, 23...
・Active element array, 31, 32, 33, 34...
・Driver terminal, 41, 42, 43... Selector terminal, 5... Multilayer wiring section, 51, 52,
53...Insulating substrate, 60...Substrate, 6
01,602,603,604,601',602',
603', 604'... Lead wire, 611, 6
12,613,...631,~634... Lead wire.

Claims (1)

[Claims] 1 A plurality of heating elements for printing in a single row multi-dot method are arranged linearly in one row on the board, and each block is composed of n heating elements each (m and n are natural numbers). One end of the heating element is commonly connected for each block and connected to a first external terminal, and the other end of the heating element is commonly connected to one heating element for each block and connected to a second external terminal, In a thermal head in which a selected heating element in the block generates heat due to a voltage selectively applied between a first external terminal and a second external terminal, a connection between the second external terminal and the other end of the heating element is provided. The connection structure includes a first lead wire that is provided on the substrate from each heating element in mutually opposite directions for each adjacent block, and a first lead wire that connects the i-th block (
Create every other pair with the i+2)th block (i is a natural number smaller than m-1), and in each pair, one heating element of each pair is selected one by one from both ends of each block. means for connecting a set of n second lead wires connected in the same plane and provided on a substrate and parallel to the array, and corresponding second lead wires of each block via another substrate; A thermal head characterized by having.