JPH04169247A - Thermal printing head - Google Patents

Abstract

PURPOSE:To improve printing quality with printing pressure concentrated by a method wherein a curved slope is provided on one side of a substrate with a glazed glass part formed on the boundary between the curved slope and the surface of the substrate, and a heat-generating part is so formed that it reaches the boundary. CONSTITUTION:After grooving 11 is applied to a substrate 1, glass paste is printed on the boundary 6 of the grooved part 11 in such a way that the printing of glass paste is applied on the opposite sides facing the grooved part 11. Then burning is applied to the printed surface, and thereby a substrate for a thermal head on which glazed glass 2 is formed is obtained. The glazed glass 2 may be formed on one side of the grooved part 11. However, forming of the same on the opposite sides is more desirable because it makes processing simple and reduces the costs. Then patterning is applied to this thermal head substrate by thin film processing such as PVD, CVD or the like and by normal photolithographic method. After a heat-generating part 3 is formed therewith, a protecting layer 10 is formed by filming, and thermal heads are made up by cutting the substrate on specified cutting positions 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal head used in printers, facsimiles, video printers, and the like.

[Prior Art] (1) Conventionally, for example, as shown in FIG. 3, a thermal head is known in which a glass glaze 2 is formed on a substrate 1 and a heat generating part 3 is formed close to the edge of the glass glaze. It was getting worse. (hereinafter referred to as C type) As shown in FIG. 4, a thermal thermal conductor is provided in which an inclined surface 4 is provided at one end of the substrate l, a conductive layer 1i5 is formed near the inclined surface, and a glass glaze 2 is further formed on the conductive film. Head was known. (hereinafter referred to as d type) (2) The conventional end face type thermal head has a 7th
As shown in the figure, a manufacturing method has been known in which a glass glaze 2 is formed on one end surface of a substrate 1, a heat generating part 3 is formed on the glass glaze 2, and the substrate is divided.

[Problems and objectives to be solved by the invention] (1) However, in a thermal head with a structure like the C type, the pressing of the head that corresponds to the recent improvement in image quality has become unable to cope with the concentration of pressure. .

That is, when forming a heat generating part on a glass glaze formed on a substrate, the heat generating part is now formed near the glass glaze, which has a smaller radius of curvature, in order to prevent pressure dispersion during pressing. However, according to this method, the printing angle of the head must be increased in order to print at the correct position, and this increase in printing angle causes the edge of the substrate to come into contact with the ink film or paper, and the printing pressure is conversely dispersed. This has become a problem due to staining or streaks caused by contact. Further, in a thermal head having a configuration like the d type, it has become possible to form a heat generating part closer to the glaze, but the radius of curvature is still not small enough. Furthermore, there is a problem in that the radius of curvature of the edge of the glaze varies due to variations in the melt viscosity of the glass glaze during firing.

(2) In addition, with the method of manufacturing thermal heads by forming a glass glaze on the edge of the substrate, it is possible to obtain a maximum of two rows of thermal heads on one substrate for the serial type, and only two chips for the line type, which is a cause of high costs. It had become.

The thermal head according to the present invention aims to provide a thermal head with good printing quality at a lower cost by stably forming a glass glaze portion with a smaller radius of curvature and concentrating printing pressure.

[Means for Solving the Problems] Therefore, as shown in FIG. 1 (hereinafter referred to as type a), the thermal head of the present invention is provided with an inclined curved portion 4 at one end of the base ff1l, and the inclined curved surface 4 and the substrate surface are connected to each other. A glass glaze 2 is formed on the boundary, and a heat generating part 3 is further formed near the boundary 6, preferably over the boundary 6. Further, as shown in FIG. 5, a grooved portion 11 is formed on the substrate 1, and a glass glaze 2 and a heat generating portion 3 are formed so as to face each other with the grooved portion 11 interposed therebetween.

[Example] An example according to the present invention will be described based on the drawings, but the thermal head can be used regardless of whether it is a serial type or a line type.
Applicable. Further, as shown in FIG. 2, in the thermal head of the present invention, it is possible to form a conductive film 5 under or near the glass glaze 2, so that the resistance value of the nine common electrodes can be reduced. It is more desirable to reduce the

(1) For samples of types c and d, the heat generating part should be formed as much as possible at the edge of the glass glaze 2, that is, at the smallest radius of curvature of the glass glaze 2, and at one end of the substrate as shown in Figure 1. In addition, as shown in FIG. 2, a conductive layer 15 is formed by thick film printing under the glass glaze, and a heat generating part 3 is formed on the boundary part 6. (I) Print evaluation (II) The rate of decrease in the exothermic peak temperature when all dots are energized relative to the exothermic peak temperature when one dot is energized was evaluated.

For the evaluation of the prints in (I), a paper called rough paper was used for -a, and the number of print defects was compared for comparative evaluation. Also,
(II) To explain the decrease in the heat generation temperature peak, in a thermal head, each electrode (segment electrode) connected to each heat generation part and the electrode (common electrode) connected in common to all heat generation parts are used. ), and in the standby state (non-printing state), this segment 1 pole and the common electrode are kept at the same potential (High). During printing, the segment side is grounded, and current flows from the common electrode to the segment side via the heat generating section. For example, when the energy required to energize one dot (resistance value R) and obtain the required peak temperature is ε (mj), the pulse width at that time is t, and the number of energized dots is n, then the common electrode The total current i flowing through is expressed as 1=nl (ε/(Rt)). When the resistance value of the common electrode is Rc, the voltage drop ΔV at the common electrode is expressed as ΔV=niRc=nRc7 (ε/(Rt)). Therefore, when more dots are energized, the voltage drop increases in proportion to the number of energized dots, so the voltage actually applied to the heat generating part decreases, and the heat generation temperature when energizing one dot and the heat generation temperature when multiple dots are energized decrease. There will be a difference in temperature.

Table 1 shows the evaluation results for (I) and (II). However, O~× in the table represents a change from good to poor.

Table 1 In the print evaluation, the C type had the most print defects, while the D type had considerably fewer print defects.

In types a and b, there were almost no printing defects. The reason why the C type is evaluated better than the C type in terms of temperature reduction rate is because the common electrode is also formed on the inclined surface, so the common electrode area is increased.

(2) The method for manufacturing the thermal head of the present invention will be explained based on the drawings, and the substrate materials include alumina, glass,
Various materials can be used, such as metal treated with insulation. Fifth
In the figure, after groove processing 11 is performed on the substrate 1, glass paste is printed by screen printing on the boundary part 6 of the groove processing part 11 so as to oppose it through the groove processing part 11,
Firing is performed to obtain a substrate for a thermal head on which glass glaze 2 is formed. Further, as shown in FIG. 6, it is possible to form the glass glaze 2 only on one side without opposing the grooved portion 11, but by forming it opposingly, the process is simplified and costs are reduced. Because it is measured,
More desirable. PVD on the thermal head substrate,
After patterning is performed using a thin film process such as CVD and ordinary photolithography to form the heat generating portion 3, a protective layer 10 is formed and cut at a predetermined cut position 12 to obtain a thermal head.

[Effects of the Invention] As described above, according to the present invention, it is possible to stably manufacture a glass glaze surface with a smaller radius of curvature,
High image quality is possible. Furthermore, by providing a conductive film under the glaze, there is an effect that the rate of decrease in heat generation temperature when all dots are energized compared to when one dot is energized can be kept low.

Further, according to the manufacturing method of the present invention, the number of sheets to be removed from one substrate is significantly greater than that of the conventional method for manufacturing edge-type thermal heads, so that it is possible to significantly reduce costs.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the thermal head of the present invention. 1... Substrate 2... Glaze glass 3... Heat generating part 4... Inclined curved surface 6... Boundary part 7... Heat generating resistor layer 8... Segment electrode 9... Common electrode 10. -Protective layer FIG. 2 is a sectional view showing an example in which a conductive film is provided under the glass glaze of the thermal head of the present invention. 5...Conductive film FIGS. 3 and 4 are cross-sectional views of a conventional thermal head. FIG. 5 and FIG. 6 are a perspective view and an enlarged sectional view showing the method of manufacturing a thermal head of the present invention. 11...Groove processing portion 12...Cut position FIG. 7 is a perspective view showing a conventional method of manufacturing an end face type thermal head. Applicant Seiko Epson Co., Ltd. Representative Patent Attorney Kizobe Suzuki and 1 other person (C tie 7゛) Figure 3 (dVia) Figure 4

Claims (2)

[Claims] (1) A substrate, a glass glaze formed on the substrate,
In a thermal print head having a heat generating part formed on a glass glaze, an inclined curved surface is formed at at least one end of the substrate, and the inclined curved surface is formed at least at a boundary between the inclined curved surface and the film-forming surface of the substrate. A thermal print head characterized in that a glass glaze is formed, and the heating section is formed near a boundary between the inclined curved surface and the substrate surface, preferably over the boundary. (2) The thermal print head according to item 1, characterized in that an inclined curved surface is formed by processing a groove in the substrate in advance, and a glass glaze and a heat generating part are formed so as to oppose each other through the groove.