JP2588957B2 - Manufacturing method of thermal head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thermal head used in a recording device such as a facsimile, a word processor, and a computer.

[Conventional technology]

First, an example of such a thermal head will be described with reference to FIG.

In FIG. 5, a glaze layer 2 for heat storage having an upper surface formed in an arc-shaped cross section is formed near an end on a substrate 1 made of an insulating material such as ceramic. A plurality of heating resistors 3 are formed in an array on 2, and a common electrode 4 and an individual electrode 5 are connected to both ends of each heating resistor 3. Further, the respective heating resistors 3, the common electrode 4 and the individual electrodes 5 are covered with a protective layer 6.

In such a conventional thermal head, the longitudinal center of the heating resistor 3 is formed at a distance from the end of the substrate 1 in FIG. Since the peeling angle (θ ゜) cannot be made large, it was necessary to use a wax-based ink ribbon I having a low melt viscosity. When printing is performed using such a wax-based ink ribbon I having a low melt viscosity, clear printing can be performed on paper having a surface smoothness of 100 seconds or more, but smoothness of 20 to 60 seconds. No clear printing was possible on plain paper, and even rough paper with a smoothness of 10 seconds or less used in Europe and the United States was difficult to print.

Conventionally, in order to solve such a problem, the substrate is cut and polished so that the heating resistor 3 of the thermal head is located at an end of the substrate 1 so that the heating resistor 3 and the paper P are pressed. In addition to the concentration of force, the peeling angle of the ink ribbon I is increased, and a relatively clear print can be obtained even on rough paper by combining the ink ribbon I with a resin-based ink ribbon I.

[Problems to be solved by the invention]

However, in the structure of the conventional improved thermal head as described above, when the heating resistor is merely an edge type located at the end of the substrate, the individual electrode and the common electrode are sandwiched between the heating resistor. Because of the arrangement, the width of the common electrode becomes extremely narrow, especially when all dots are energized at the same time when all the heating resistors are energized. However, there was a problem that the calorific value was remarkably reduced and clear printing could not be performed, and the common electrode was burned out due to insufficient current capacity.

As a method for removing such a problem in the conventional thermal head, there is a thermal head described in JP-A-61-196663, in which a communication hole communicating with a common electrode is formed in a protective layer. A collective electrode electrically connected to each common electrode via each communication hole is provided on the protective layer.

However, the thermal head described in this publication connects the collective electrode and the common electrode by curving the collective electrode in the communication hole, so that the electrical connection between the collective electrode and the common electrode is stabilized. There was a problem of poor sex.

The present invention solves the above-mentioned problems in the conventional device, and can supply a sufficient current to the heating resistor so that a voltage drop does not occur, and the heating resistor can reliably generate heat. A thermal head that can print sharply on rough paper, does not have the risk of burning the common electrode due to insufficient current capacity, and stabilizes the electrical connection between the common electrode and the collective electrode can be easily manufactured. It is another object of the present invention to provide a method of manufacturing a thermal head which can be manufactured with a high yield.

[Means for solving the problem]

In order to achieve the above-mentioned object, a method of manufacturing a thermal head according to the present invention comprises sequentially forming a heating resistor layer and an electrode material layer on a glaze layer, and eliminating unnecessary portions from the heating resistor layer and the electrode material layer. To form heating resistors in a number corresponding to the number of dots and individual electrodes and common electrodes derived from these heating resistors in the same direction, and cover these heating resistors, individual electrodes and common electrodes with a protective layer. Then, a plurality of communication holes respectively communicating with the common electrode are formed in the protective layer, and a current-carrying member connected to the common electrode and made of a metal having good solderability is formed in the communication holes on the surface of the protective layer. It is characterized in that it is heated and welded after stacking a thin-film collective electrode made of a metal having good solderability on the protective layer including the current-carrying member. To have.

(Operation)

According to the method of manufacturing a thermal head of the present invention having the above-described configuration, a glaze layer is provided on a substrate, and a heating resistor, an individual electrode, and a common electrode are provided on the glaze layer. Forming a mechanically stable protective layer covering the electrode and the common electrode, and further forming a collective electrode made of a good metal with good solderability on the mechanically stable protective layer as the protective layer and the conducting member. Due to the heat welding, the common electrode and the common electrode are connected via a current-carrying member to be electrically stable, and a defective product is caused when the common electrode is connected to the collective electrode via the current-carrying member in a multilayered electrode wiring. It can be manufactured with high yield without fear.

〔Example〕

 Hereinafter, the present invention will be described with reference to embodiments shown in the drawings.

FIGS. 1 and 2 are a plan view and a longitudinal sectional view, respectively, showing a first embodiment of a thermal head manufactured by a method of manufacturing a thermal head according to the present invention.
In the figure, reference numeral 11 denotes an insulating substrate made of a ceramic such as alumina and having a thickness of about 0.6 mm. At one end of the upper surface of the substrate 11, a partial glaze layer 12 having a maximum height of about 40 to 60 μm at the center top and an arc-shaped upper surface having a width of about 0.8 mm and serving as heat storage is formed. Have been. On the top of the glaze layer 12, a plurality of heating resistors 13 corresponding to the number of dots as heating elements are formed in an array. The heating resistor 13 is made of Ta ₂ N or the like, and has a thickness of about 0.
As shown in detail in FIG. 1, two adjacent heating resistors 13 are formed on one end of the substrate 11 by means of a folded electrode 13A so as to be joined at both ends. Are formed in a substantially U-shaped plane directed toward the center of the substrate 11. At both ends of the heating resistor 13, a common electrode 14 and an individual electrode 15 formed on the substrate 11 and the glaze layer 12 and made of Al or the like and having a thickness of about It is connected to be led to the side. Of these, each common electrode 14 is connected to two adjacent heating resistors 13. Furthermore, the substrate 11, the glaze layer 12, the heating resistor 13, and the common electrode 1
4. On the surface of the individual electrode 15, an oxidation-resistant and wear-resistant protective layer 16 made of Si ₃ N ₄ or the like having a thickness of about 5 μm is provided.
The protective layer 16 covers the heating resistor 13, the common electrode 14, the individual electrodes 15, and the like, and is protected from oxidation and abrasion.

The protective layer 16 is provided with a plurality of communication holes 17 communicating with the common electrode 14, respectively. A collective electrode 18 is formed on the protective layer 16 so as to be located at the center of the substrate 1. The collective electrode 18 is a conductive member 19 formed in each communication hole 17. Are electrically connected to the common electrode 14 respectively. This collective electrode 18
Is made of a wide metal wire or a thin metal plate such as Al, and is connected to the common electrode 14 by a current-carrying member 19 made of a solder or a conductive adhesive inserted into the communication hole 17. . Further, as another embodiment of the collective electrode 18, the conductive paste may be formed by printing and firing. In this case, the conductive paste is also inserted into the communication hole 17 to form the current-carrying member 19, so that the common electrode 14 is formed.
May be connected. Further, the collective electrode
The metal 18 may be formed by providing a metal patterned on the protective layer 16 by a photoengraving technique, and plating this metal with another metal having solderability.

According to such a thermal head of the present embodiment, the plurality of common electrodes 14 derived from the heating resistor 13
Is connected to the collecting electrode 18 on the protective layer 16 through the conducting member 19 in the communication hole 17 at an arbitrary position, and the power is supplied through this collecting electrode 18. It can be adjusted arbitrarily. Therefore, by forming the width of the collective electrode 18 large, a sufficient current can be generated.
13 can be prevented, and a printing failure due to a heating failure of the heating resistor 13 can be prevented. As a result, clear printing can be performed even on rough paper. Further, since the current capacity of the collective electrode 18 can be freely set, there is no possibility that the common electrode 14 will be burned out due to insufficient current capacity.

Next, a method for manufacturing the thermal head according to the present invention will be described in detail.

First, the glaze layer 12 is formed on the substrate 11 so as to be in contact with one end of the substrate 11. Next, a heating resistor layer 13a and electrode layers 14a and 15a are sequentially formed on the glaze layer 12 by a vapor deposition technique. Then, unnecessary portions are removed from the heating resistor layer 13a and the electrode layers 14a and 15a by photoengraving technology, and the plurality of heating resistors 13 and the folded electrodes 13A and the same direction from these heating resistors 13 are removed. The common electrode 14 and the individual electrode 15 are formed.
After the common electrode 14 and the individual electrode 15 are formed, the common electrode 14 and the individual electrode 15 may be plated with a metal having good solderability. Further, after the common electrode 14 and the individual electrode 15 are formed, an insulating and moisture-proof coating can be applied with an organic material.

Next, a protective layer 16 is formed so as to cover the heating resistor 13, the common electrode 14, and the individual electrode 15.
Then, a common electrode is formed on the protective layer 16 by photolithography.
A plurality of communication holes 17 communicating with 14 are formed. Then, after forming the communication holes 17 in the protective layer 16, on the surface of the common electrode 14 facing the inside of each communication hole 17 and on the inner peripheral side of the communication hole 17,
Each of the current-carrying members 19 made of metal having good solderability is plated so as to slightly protrude from the surface of the protective layer 16 to form a current-carrying member 19 electrically connected to the communication hole 17. A thin-film collective electrode 18 made of a metal having good solderability is stacked on the protective layer 16 containing, and is welded by heating and connected to the protective layer 16 and the conducting member 19.

As described above, according to the method of manufacturing a thermal head according to the present embodiment, the glaze layer 12 is provided on the substrate 11, the common electrode 14 and the individual electrode 15 are provided on the glaze layer 12, and these two electrodes 14, 15 are provided. A protective layer 16 that is mechanically stable is provided so as to cover the protective layer 16, a communication hole 17 is formed in the protective layer 16, and good soldering is performed so that the communication hole 17 slightly protrudes from the surface of the protective layer 16. Plating the conductive member 19 made of
Since the thermal head is manufactured by forming the conductive member 19 electrically connected to the communication hole 17 and providing the collective electrode 18 on the protective layer 16 and the conductive member 19 by heat welding,
The electrode wiring can be easily multilayered without complicating it, and can be manufactured with good yield. In addition, the electrical connection between the common electrode 14 and the collective electrode 18 is stably performed through the conducting member 19. be able to.

FIGS. 3 and 4 show a second embodiment of a thermal head manufactured by the method of manufacturing a thermal head according to the present invention. In this embodiment, a plurality of thermal heads each connected to an individual electrode 15 are shown. The integrated circuit element 20 is mounted.

Also in the thermal head equipped with such an integrated circuit element 20, the conducting member 19 electrically connected to the common electrode 14 is formed in the communication hole 17 of the plurality of protective layers 16 respectively communicating with each common individual electrode 14. The arrangement is substantially the same as that of the first embodiment described above, with the interposition and the formation of the collective electrode 18 electrically connected to each of the conducting members 19 on the protective layer 16. Note that the glaze layer 12 in this embodiment is laminated on the entire surface of the substrate 11. Other configurations are the same as those of the first embodiment, and therefore, the same reference numerals are given in the drawings, and the description thereof will be omitted.

According to the second embodiment, the same operation and effect as those of the first embodiment can be obtained.

Note that the present invention is not limited to the above-described embodiments, and various modifications can be made as necessary.

〔The invention's effect〕

As described above, according to the method of manufacturing a thermal head according to the present invention, the plurality of communication holes formed in the protective layer include:
A conductive member made of a metal having good solderability connected to a common electrode is plated so as to protrude slightly from the surface of the protective layer, and a thin film made of a metal having good solderability is formed on the protective layer including the conductive member. The stacked electrodes are stacked and heated and welded, so that the electrical connection between the common electrode of the thermal head and the collected electrode can be stably performed by the conducting member in the communication hole, and also easily. In addition, the thermal head can be manufactured with a good yield.

[Brief description of the drawings]

FIGS. 1 and 2 show a first embodiment of a thermal head manufactured by the method of manufacturing a thermal head according to the present invention. FIG. 1 is a partially cutaway plan view showing the inside of the thermal head. FIG. 2 is a longitudinal sectional view of FIG. 1, FIGS. 3 and 4 show a second embodiment of a thermal head manufactured by the method of the present invention, and FIG. Partial cutaway plan view showing interior, fourth
FIG. 3 is a longitudinal sectional view of FIG. 3, and FIG. 5 is a longitudinal sectional view showing a main part of a conventional thermal head. 11 ... substrate, 12 ... glaze layer, 13 ... heating resistor, 13
a: Heating resistor layer, 14: Common electrode, 14a, 15a: Electrode layer, 15: Individual electrode, 16: Protective layer, 17: Communication hole, 18
... collective electrode, 19 ... current-carrying member, 20 ... integrated circuit element.

Claims (1)

(57) [Claims] 1. A heating resistor layer and an electrode material layer are sequentially formed on a glaze layer, and unnecessary portions are eliminated from the heating resistor layer and the electrode material layer so that the number of heating resistors corresponding to the number of dots is reduced. And forming an individual electrode and a common electrode extending in the same direction from the heating resistor, covering the heating resistor, the individual electrode and the common electrode with a protective layer, and communicating with the protective layer to the common electrode, respectively. A plurality of communication holes to be formed, and a current-carrying member connected to the common electrode and made of a metal having good solderability is plated in these communication holes so as to slightly protrude from the surface of the protective layer. A method of manufacturing a thermal head, comprising laminating a thin-film collective electrode made of a metal having good solderability on the protective layer comprising: