JPS5851831B2 - Thermal head device - Google Patents

Abstract

PURPOSE:To improve the mass-productivity and reliability of a thermal head by connecting array blocks of exotermic resistors and diodes by way of film in which conducting wires are arranged.

Description

[Detailed description of the invention] The present invention relates to an improvement in the structure of a thermal head device.

In general, a thermal head recording device consists of a row or matrix of heating resistors made of minute heat-resistant resistance materials.
A specific heating element is selected from among the IJ boxes and energized, causing the thermal paper that comes into contact with it to develop color.
It visualizes electrical information.

When considering an application such as a 7-axis thermal head, it is necessary to arrange a large number of heating elements in a row and to electrically control each of them.

In such a case, it is common to wire as shown in FIG. 1 to simplify the circuit.

However, in order to simplify the external circuit, the Ro of each group of resistors is
・・・・・・Agitation is a unit of a certain number N, usually 8゜16
．． It is determined to be either N=2 (n is any integer) such as 32 or 64.

By repeating this unit of N M times, for example, if N = 16, the circuit will look like the one shown in Figure 1, and the external circuit will have N driver circuits for heating elements,
By switching it with M switching circuits, M
XN matrix control becomes possible.

However, in this case, the heating element resistance has no polarity, so a backflow prevention diode D is connected in series to each resistance.
1... DN must be placed.

Of course, this diode can also be replaced by a transistor.

On the other hand, when performing thermal printing, the resolution of heating elements is becoming increasingly important, and it is necessary to have a minimum resolution of 4 heating elements per liter, that is, to form and drive 4 heating elements per 1m11L. It has become necessary to do so.

Therefore, in order to satisfy the necessary printing conditions, which are determined by the printing paper width, it is usually necessary to form several hundred or more heating elements, and in order to achieve that precision, all wiring and element formation must be done by photoetching. However, since the physical size of the head itself is equal to the width of the thermal recording paper, its processing is not necessarily easy.

Thermal heads are expected to be in great demand in the future due to their simple primary coloring ability, but for this purpose, significant reform is required from a productivity standpoint.

A conventional thermal head is roughly divided into three parts.

That is, the heating element, the corresponding row of electrodes, the backflow prevention diode array, the button, and the multilayer wiring section to enable matrix drive.

If all of these are to be formed on the same substrate, the whole can be compactly integrated into one, but on the other hand, it is difficult to process and yield problems in the process of forming each element button and wiring on a large substrate. .

If these three parts were manufactured separately, the above problem could be avoided to some extent, but connecting them would create a problem that was extremely difficult to solve. At present, no optimal solution has been found.

The present invention solves the above technical problems and provides a thermal head that is mass-producible and highly reliable.

The details of the present invention will be described below.

Figure 2 shows the structure of the heat generating resistor array block used in the thermal head of the present invention, in which 1 is a heat-resistant substrate with strength and insulation properties similar to ceramics, and the surface is smoothed and heat-retaining. Therefore, a glass layer 6 may be provided on the front surface.

3 is a heating resistor formed in a line in a dot shape approximately in the center of a rectangular substrate, and is usually made of nichrome, silicon with a high impurity concentration, carbide, silicide, nitride resistor, etc. by vapor deposition or sputtering. It is formed into a thin film by this method.

4 and 2 are electrode terminals to the resistor, and metal thin films such as nickel, gold, aluminum, etc. are used.

The electrode terminals 2 are on the separated electrode side, and the electrode terminals 4 are electrodes between common terminals connected by a specific number N.

In addition, 5 (the shaded area in Figure 2) is a wear-resistant layer to prevent wear caused by the element coming into contact with paper, and is made of materials such as silicon carbide, nitride, and oxide with a thickness of several microns. It is formed by

A large number of rows of such heating elements can be manufactured by cutting or breaking a large substrate, which is excellent in terms of productivity.

Furthermore, in order to facilitate connection with film leads as will be described later, the rows of separation terminals 2 have their tips gradually tapered relative to the heating element group.

Note that FIG. 3 is a cross section taken along lines A and A' in FIG. 2.

4 and 5 are perspective views of the conductor wire block 12 and the conductor wire film 13, showing the structure of the wiring portion constituting the matrix.

The substrate 11 in FIG. 4 is made of an insulating material with little distortion, and on it there are conductor wires 10 arranged every N.
=16 groups, and the M groups are formed so as to be repeated.

As will be described later, the ends a of the conductor wires 10 are formed in parallel with the ends aligned at the positions where they will be connected to the button terminals 2 shown in FIG. It is formed by being bent at right angles to the

Processing such wiring requires high precision, and usually a material with high adhesion and conductivity such as chromium, copper, nickel, silver, or gold is coated over the entire surface of the substrate 11 with a single layer or a combination of these materials. It is produced by vapor deposition and then subjecting it to a photo-etching process.

The substrate 8 is used to attach a directional semiconductor element, which will be described later, and is used to maintain a constant distance between the heat generating resistor array block 7 and the conductor wire bronze 2120.

This may also be made integrally with the substrate.

A shallow groove 9 is formed on the substrate 8 to facilitate housing of semiconductor elements.

The heating resistor array block 7 is not made individually, but can be easily manufactured in mass production by performing evaporation and photoetching with the same pattern on a fairly wide substrate, and by cutting it into strips for later processing. It is possible to do so.

FIG. 5 shows a conductor section for commonly connecting the group of terminals shown in FIG. 4, in which N narrow conductor wire groups 15 are formed on a flexible insulating film 13.

The pitch of the N conductors is matched to each of the ends shown in FIG. It is exposed so as to be electrically and mechanically connected to the end b of the.

Cross-sectional views of the CC7 plane and the BB' plane of this conductor wire film 24 are shown in FIGS. 6A and 6B.

This conductor wire film 24 is placed on the conductor wire block 12 so that the conductor wires in the openings 14 and the ends of the conductor wires 10 of the conductor wire block 12 shown in FIG. 4 are in contact with each other.

FIG. 7 shows an example of the process of connecting directional semiconductor elements inserted into each group of conductor wires.

The diode array 16 has N separated diodes formed on the same substrate.

Each bump terminal is indicated by 17.

Nine rows of conductor wires 20, 21 protruding from both ends are formed on a heat-resistant elongated film 18, 19 such as polyimide. Usually, copper foil is processed by a photo-etching process, and gold, tin, etc. It is plated with.

As shown in FIG. 8, the semiconductor element is manufactured by overlapping the conductor ends and the bump terminals 17 on the diode array 16, and attaching one or both terminals to the film 1 at a time by a method such as thermocompression bonding.
It can be connected to the conductor 2021 on 8 and 19.

FIG. 9 shows a cross section taken along plane 097 in FIG. 7 when conductor terminals are connected to both sides of the semiconductor element.

In this state, the device is inspected and transferred to the final thermal head assembly process.

FIG. 10 shows the heat generating resistor array block 7, the diode array block 16 button, the diode play mounting board 8, the films 18 and 19 buttons that support the conductor wires connected to the diode array, and the conductor wire block 12 on the same basis. 3 is a diagram showing a configuration in which the device is attached onto a stand 22 with an adhesive or the like and fixed with a metal fitting 23. FIG.

In this state, the diode array 16 having conductor protrusions on both sides is connected to the film 18 disposed on both sides of the groove of the substrate 8.
The conductor wires on 19 are joined by means such as thermocompression bonding.

That is, -25 is a common terminal of the heating resistor array block.

FIG. 11 shows the state in the final assembly process, in which the ends of the conductor wires on the conductor wire block 12 shown in FIG. 4 are commonly connected for each group by the conductor wire film 24 shown in FIG. 5. .

The conductor wire in the opening 14 of the conductor wire film 24 is connected to the end portion.

In the above configuration, the diode array support substrate on which the heating resistor play block and the connecting conductive wires are provided and the conductor wire block are aligned and fixed in advance, and each group of conductor wires attached to the conductor wire block is fixed. It is efficient to arrange a diode array in the groove of the substrate and electrically connect it with the connecting conductor wire.

As described above, since each part of the thermal head device according to the present invention can be configured separately, an appropriate manufacturing method can be used for each part, and the diode play block has an end protruding and a semiconductor line is provided. Since a film is used, the connection is easy, and since a conductor wire block using a film is used in the multilayer wiring section, the insulated wiring and connection can be simplified.

[Brief explanation of drawings]

Figure 1 is an electrical connection diagram of a heating element in a conventional example, Figures 2 to 11 are related to an embodiment of the present invention, Figure 2 is a diagram showing the structure of a heating resistor array, Figure 3 is the second
AA' plane sectional view in the figure, Figure 4 and Figure 5 are diagrams showing the wiring board which is a component of the thermal head device, Figure 6A
, B are a sectional view on the B B' plane and a sectional view on the CC' plane of FIG. 5, FIG. 7 is a configuration diagram of the diode array, FIG. 8 is a diagram showing the connection between the film conductor and the diode array, and FIG. 9 are DD' plane cross-sectional views in Fig. 7, Fig. 10 and 1
FIG. 1 is a block diagram and a completed diagram of an assembly process of a thermal head device according to an embodiment of the present invention, respectively. 7... Heating resistor array block, 8...
...Substrate, 9...Groove, 10...Conductor wire, 11...Substrate, 12...Conductor wire block, a, b... ... End, 13... Flexible insulating film, 14... Opening, 15...
...Conductor 1.16...Diode array block, 17...Terminal, 1B, 19...Film, 20°21...Conductor wire, 22・・・・・・
... Base, 23 ... Metal fittings, 24 ... Conductor wire film, 25 ... Common terminal.

Claims (1)

[Scope of Claims] 1. A heat generating resistor array block in which a plurality of heat generating resistors are arranged in a row, a substrate having a diode array housed in a groove, and connections electrically connected to the diode play on both sides of the groove. a diode play block consisting of a film that supports conductor wire groups for use; one ends of the conductor wire groups arranged in predetermined numbers at positions corresponding to the diode arrays of this diode play block are arranged in the arrangement direction of the diode arrays; A conductor wire block having ends thereof arranged in a direction perpendicular to the conductor wire block, and a conductor wire for connection having the same number of conductor wires as the conductor wires of this conductor wire block and extending in the arrangement direction of the heating resistor array block on the upper surface, and the conductor wires. an insulating film provided with an opening at each position corresponding to the other end of the block, each of the heating resistors and each of the diodes,
Each of the diodes and an end of the conductor wire block are electrically connected by a connecting conductor wire of the diode array block, and the other end of the conductor wire block is connected to the connecting conductor wire through an opening in the insulating film. A thermal head device characterized by being electrically connected. 2. A thermal head device according to claim 1, characterized in that the conductor wire group of the diode array block protrudes from the support film. 3. A thermal head device according to claim 1 or 2, characterized in that the diode play block is divided into blocks for each conductor wire group of the conductor wire block.