JP2865788B2 - Manufacturing method of thermal head - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a thermal head.

[Related Art] A thermal head is widely used as a printing apparatus such as a facsimile communication apparatus. In manufacturing a thermal head, a head substrate is used in which a plurality of heating elements are formed linearly and a plurality of electrodes for individually supplying power to each heating element are formed. Each heating element is selectively driven to heat by a drive circuit element in accordance with data to be printed. The drive circuit element is mounted on a drive board made of a material having an electrical insulating property separate from the head substrate, and a plurality of electrodes connected to the drive circuit element are formed on the drive board as circuit wiring. The head substrate and the driving substrate are fixed on the heat sink at an interval, and the flexible wiring substrate is connected to connection terminals formed on the electrodes of each substrate by soldering, respectively. Are electrically connected.

[Problems to be Solved by the Invention] Conventionally, when manufacturing a thermal head of this type, a head substrate and a drive substrate are integrally manufactured and separated from the same material such as ceramics as described above. Are connected to a flexible wiring board. For this reason, when the head substrate and the drive substrate are soldered to the flexible wiring substrate in separate steps before and after in time, respectively, when soldering is performed in a later step, the connection portion extends over a plurality of connection terminals. In some cases, the heat generated by the heating means having a planar shape that is heated all at once is transmitted to the side where the solder connection has been completed via the flexible wiring board, and the solder may be melted again. When such a situation occurs, a connection failure is caused. In addition, when the respective substrates and the connection substrate are connected by soldering at the same time, it is necessary to perform positioning and connection at two connection portions at the same time, and such positioning is difficult and requires a lot of labor. There is a problem that.

An object of the present invention is to solve the above-mentioned technical problems and to provide a method of manufacturing a thermal head in which the manufacturing process is significantly simplified.

Means for Solving the Problems The present invention provides a head substrate on which a plurality of heating elements, a plurality of electrodes for individually energizing the heating elements are formed, and a drive circuit element for energizing the heating elements And a driving substrate on which a plurality of electrodes connected to the driving circuit element are formed, using a connection conductor, to manufacture a thermal head. Are made of different materials, and the electrodes of the substrate having high thermal conductivity and the connection conductors are melt-connected, and then the electrodes of the substrate having low thermal conductivity and the connection conductors are melt-connected. This is a method of manufacturing a thermal head.

[Operation] According to the present invention, the thermal conductivity of the head substrate and the thermal conductivity of the driving substrate are selected to be different values. Among these substrates, the electrodes of the substrate having a high thermal conductivity and the connection conductor are fusion-connected, and the electrodes of the remaining substrates of the respective substrates are fusion-connected to the connection conductor. When the remaining substrate and the connection conductor are fusion-connected, the remaining substrate has a lower thermal conductivity, and a sufficient amount of heat for connection can be obtained.

At this time, the heat for connecting the remaining substrate to the connection conductor is transmitted to the connection with the substrate having the higher thermal conductivity through the connection conductor, but the transmitted heat is converted to the thermal conductivity. Is rapidly diffused from the connection portion on a substrate having a large heat dissipation. For this reason, it is possible to prevent the temperature of the connection between the electrode of the substrate having a high thermal conductivity and the connection conductor from melting again. As a result, the head substrate and the drive substrate can be reliably electrically connected by the connection conductor. In addition, since these substrates and the connection conductors are connected in separate steps that are temporally delayed, alignment during connection becomes easy. In this way, the manufacturing process is simplified.

Embodiment FIG. 1 is a plan view of a thermal head 1 manufactured according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the thermal head 1. The thermal head 1 includes a heat radiating plate 2 made of, for example, aluminum, on which a head substrate 3 made of a ceramic material such as alumina and a driving substrate 4 made of an epoxy resin material reinforced with glass fiber are fixed with an adhesive or the like. Is done. The thermal conductivity of the head substrate 3 is, for example, 60 × 10 ⁻³ (cal / cmsec ° C.), and the thermal conductivity of the drive substrate 4 is, for example, 2 × 10 ⁻³ (cal / cmsec ° C.).
It is.

On the head substrate 3, a thick film common electrode layer 5 and a glaze layer 6 are formed, and a heating resistor layer 7 is formed thereon. A common electrode 8 and an individual electrode 9 are formed on the heating resistor layer 7, and a plurality of heating resistor elements 10 are linearly arranged. On the opposite side of the individual electrode 9 from the heating resistance element 10, a connection terminal 13 is formed in a connection portion 12 which is a connection conductor and is connected to a possible wiring board (hereinafter abbreviated as FPC) 11.

A drive circuit element 14 for selectively driving the heating resistor element 10 to generate heat is mounted on the drive board 4.
Are formed as circuit wiring. A connection terminal 17 is formed at a connection portion 16 of the electrode 15 on the FPC 11 side. The connection terminals 13, 17 are, for example, solder layers. The FPC 11 has a connecting wire 18 for individually connecting the corresponding connecting terminals 13 and 17 to a support 19 such as a synthetic resin material.
Formed on top.

FIG. 3 is a process chart for explaining the manufacturing method of this embodiment, and FIG. 4 is a plan view for explaining the manufacturing process of this embodiment. In step a1 of FIG. 3, the head substrate 3 and the drive substrate 4 are individually manufactured from an epoxy resin material reinforced with ceramics such as alumina and glass fiber as described above,
First, as shown in FIG. 4A, a head substrate 3 made of a material having a high thermal conductivity is prepared. In step a2, the connection terminals 13 of the head substrate 3 and the connection wirings 18 of the FPC 11 are connected.
As shown in FIG. 4 (2), connection terminals of the head substrate 3
13 and the FPC 11 are overlapped at the connection portion 12 thereof, and a flat heater (not shown) such as 400 to 460 ° C. or 450 to 5
It is heated to 00 ° C. and connected to the connection part 12, and both are melt-connected with solder.

In step a3 of FIG. 3, the connection terminal 17 of the drive board 4 and the connection wiring 18 of the FPC 11 are overlapped at the connection portion 16 as shown in FIG. 4 (3), and the heater is heated to 350 to 400 ° C. The two parts are brought into contact with the connection part 16 and the two are melted and connected.

In the manufacturing method of the above-described embodiment, when the head substrate 3 and the driving substrate 4 are melt-connected by soldering using the FPC11, first, the head substrate 3 and the FPC11 are connected, and then the driving substrate 4 and the FPC11 are connected. Added connection. Thus, when performing the fusion connection, the positioning is performed so that the connection terminals 13 and 17 and the corresponding connection wiring 18 in the FPC 11 overlap, but such positioning is performed by the connection section 12 or the transfer section.
It suffices to perform it in a separate step for each one of the 16 steps, and the alignment is much easier than in the conventional example. Thereby, the manufacturing process can be simplified.

In connecting the drive board 4 and the FPC 11, the connecting portion 16 and the heater are used. The heat from the heater is transmitted to the connecting portion 12 through the connection wiring 18 of the FPC 11. However, as described above, the thermal conductivity of the head substrate 3 is selected to be large, and the transmitted heat is quickly diffused from the connection portion 12 into the head substrate 3, and the temperature of the connection portion 12 is reduced to a temperature at which the solder melts. Preventing the situation from reaching. As a result, the occurrence of connection failure as described in the related art can be prevented, and the quality of the thermal head can be improved.

Both the head substrate 3 and the driving substrate 4 may be formed of ceramic, and the present invention can be implemented even when the material of the ceramic is different, such as silicon carbide, silicon nitride, and zirconia.

[Effects of the Invention] As described above, according to the present invention, when a substrate having high thermal conductivity is fusion-connected to a connection conductor and then the remaining substrate and the connection conductor are fusion-connected, the remaining substrate is thermally The conductivity is selected to be small, and a sufficient amount of heat for connection can be obtained. At this time, the heat for connecting the remaining substrate and the connection conductor is transmitted to the connection portion with the substrate having high thermal conductivity via the connection conductor, but the transmitted heat is used for the substrate having high thermal conductivity. At the connection portion, the heat is rapidly diffused and dissipated. Therefore, it is possible to prevent the temperature at which the connection between the electrode of the substrate having a high thermal conductivity and the connection conductor is melted again. As a result, the head substrate and the drive substrate can be reliably electrically connected by the connection conductor. In addition, since these substrates and the connection conductors are connected in separate steps that are temporally delayed,
Positioning at the time of connection becomes easy. In this way, the manufacturing process is simplified.

[Brief description of the drawings]

FIG. 1 is a plan view of the thermal head 1, FIG. 2 is a cross-sectional view of the thermal head 1, FIG. 3 is a process diagram illustrating a manufacturing method according to an embodiment of the present invention, and FIG. It is sectional drawing explaining a method. DESCRIPTION OF SYMBOLS 1 ... Thermal head, 3 ... Head board, 4 ... Driving board, 8 ... Common electrode, 9 ... Individual electrode, 10 ... Heating resistance element, 11 ... FPC, 12, 16 ... Connection part, 13,17 connection terminals, 14 drive circuit elements, 15 electrodes, 18 connection wiring

Claims (1)

(57) [Claims] 1. A head substrate on which a plurality of heating elements and a plurality of electrodes for individually energizing the heating elements are formed; a driving circuit element for energizing the heating elements; and a connection to the driving circuit element. A method for manufacturing a thermal head by connecting a driving substrate on which a plurality of electrodes are formed using a connecting conductor, wherein the head substrate and the driving substrate are made of materials having different thermal conductivity, A method of manufacturing a thermal head, comprising: fusion-connecting an electrode of a substrate having a high conductivity to a connection conductor; and thereafter, fusion-connecting an electrode of the substrate having a low thermal conductivity and the connection conductor. .