JPS581578A - Thermal head - Google Patents

Abstract

PURPOSE:To provide the thermal head capable of eliminating a noble metal layer under a glaze layer, wherein a first electrode layer is provided on the glaze layer and a second and a third electrodes for matrix wiring are providing thereon. CONSTITUTION:On a glazed alumina base plate 1 having a glaze layer 2' coated thereon, a U-shaped resistor film (Ta-N) 3' and a first electrode layer 4' are formed by a thin film process and a protective layer 5' is formed to a printing part in the vicinity of a thermal head 11'. In the next process, after a thick film like insulating layer 6' covering the thin electrode layer 4' of a matrix forming part is formed, a second layer of a thick film like conductive layer 7' is formed by screen printing and, after curing, a thick film like insulating layer 8' is formed and a through hole 14' is provided. To the uppermost past thereof, a third layer of a thick film like conductive layer 9' is provided to form an upper electrode and the same electrodes of each groups are connected through the through-hole 14'. The insulating layer 6' is formed by using a resin cured at 300 deg.C or less so as not to generte oxidation of the resistor 3' nor the electrode 4'.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a last-line magnifying-pull type thermal head in which a heating element is formed near the edge of a substrate, and the print can be seen immediately after printing.

Figure 1 shows a plan view of the structure of a conventional thermal head of this type (
A) and side cross section mm).

In the figure, 1 is an alumina substrate, 2 is a glaze layer, and in the conventional structure, a first electrode layer consisting of a noble metal conductor layer 15 is provided between the glaze layer 2 and the substrate 1, but the glaze layer 2 is 8
Because it is fired at temperatures above 00°C, the first electrode layer must be made of a noble metal material such as a thick film gold conductor. The glaze layer 2 is prone to defects due to its surface irregularities located on the pole layer, making it difficult to realize a long-life head.

The present invention solves this conventional drawback, and for this purpose, a first layer electrode is provided on the glaze layer, and a second layer electrode for matrix wiring is provided on the glaze layer. By providing a pole in the third NI', the noble metal thick film conductor under the glaze layer is eliminated, and a last line maggot pull type thermal head is constructed.

That is, according to the present invention, (1) electrodes are formed on the glazed alumina substrate by a thin film process to individually connect the heat generating resistor and the reverse current prevention diode to the resistor; (2) electrodes are formed on this N film; Wire from the matrix 1-layer thin film electrode to the IJ sock component using a thick film conductor. (4
) A through hole is provided in the matrix forming part to connect between the thick film electrodes, and then an insulator is formed. (5) Form a thick film conductor to connect the same select of each group to the matrix forming part. (6) For each of the two layers of thick film conductors and insulators, a thermosetting resin that hardens at a temperature of 300° C. or less or an ultraviolet curable resin is used, and patterns are formed by screen printing. (η If it is necessary to lower the resistance of the thick film conductor, a low resistance layer is formed by electrolytic plating of Cu, Ni, Au, etc. after curing.

With the above configuration, the thermal head according to the present invention can be obtained.

Embodiments of the present invention will be described below with reference to FIG.

FIG. 2 is a plan view (4) and a side sectional view (B) of the thermal head according to the present invention. First, the substrate of this thermal head consists of a glazed alumina substrate 1 coated with a glaze layer 2 as a heat storage layer. Then, on this substrate 1, a U-shaped (Ta-N) 3 resistive film and an anti-oxidation layer (Stop) and an anti-wear layer are applied to the printed area near the first layer Kw< (Ni Cr-Au 11') using a thin film process. Layer (Tax
A protective layer 5 made of O8) is formed.

As is clear from the figure, the thermal head of the Last Line Widget Type has the advantage that the heat-generating dots 11 are formed near the substrate 13, so that printed characters and figures can be seen immediately after printing.

Next, the thick film insulating layer 6 covering the thin film electrode 4 of the matrix forming portion 12 is entirely screen printed, and then heated and cured to form the thick film insulating layer 6. On top of this, a second thick film conductor layer 7 is screen printed and cured by heating to provide the lower electrodes of the two matrix forming portions.

Further, a thick insulating layer 8 is formed and through holes 14; ε are provided. At the top, a lower electrode is formed with a third layer of thick film conductor layer 9, and the same selections of each group are connected via through holes 14. The thick film insulating layer 6 and the thick film conductor layer 7 are made of a paste material containing thermosetting resin (epoxy resin), which is heated at 300° to prevent oxidation of the thin film resistor 3, electrode 4, etc. It is a low-temperature curing type that hardens at temperatures below 0, allowing for smooth and lean printing, and other resins may be used if necessary. For example, an ultraviolet curing resin can be used.

Further, in the thick film conductor paste of silver filler 9 used in this example to obtain the thick film conductor layer 7.9, when a sheet resistance is 01 Ω/hole and a pattern with a filter width of 0.2 mm is formed, this resistance is approximately 5 Ω. Become. The resistance of each element including wiring resistance is 2%
If there is a difference above, it will cause uneven printing, so in this embodiment, the thick film conductor layer 7 is
．． A low resistance layer 5 is provided on the surface of 9. This low resistance layer 15 is formed by electrolytic plating of Ni, Au, Cu, or the like.

According to the present invention described above, the conventional noble metal layer under the glaze layer can be eliminated, making it possible to reduce costs. In addition, defects in the glaze layer are reduced and a long-life head can be realized.

Furthermore, since the matrix portion can be formed only by a thick film process, it exhibits effects such as a low-cost process.

[Brief explanation of drawings]

4- FIG. 1 is a plan view (A) and a side sectional view (B) showing a conventional thermal head, and FIG. 2 is a plan view and side sectional view (B) of a thermal head according to the present invention. [Explanation of symbols] 1.1...Substrate 2゜2...Glaze layer 4'...First no electrode 6.8...:.
... Insulating layer 7 ... Conductor layer 9 that becomes the second layer electrode ...
・・・・・・Conductor layer that becomes the third layer electrode ^
Mi Takumi 423-

Claims (1)

[Claims] In the last line magnifying pull type thermal head, the 14L pole has at least a 3Iv structure, and a heating resistor is formed in the middle of the 11th electrode counting from the substrate side, and the 211th pole and the 31st electrode are matrix wiring. The thermal head is characterized in that the insulating layer between the two electrodes is formed of a low-temperature curing resin.