JPS60145863A - Thin film thermal head - Google Patents

Abstract

PURPOSE:To accomplish a high resolution which is excellent in a close adherence between a heating element of a thin-film thermal head and a heat sensitive recording paper by providing in parallel two exothermic resistors of parallel connection with one electrode through non-exothermic resistor and by selectively driving a driving electrode by different drivers. CONSTITUTION:If feeding electrode 10a1, 10a3, 10a5,... are applied with head impressing voltage, exothermic resistors 81, 82, 85, 86... become ready for printing, and by the switching elements that are to be connected with feeding electrodes 10b1, 10b2, 10b3,..., optional dots can be made to generate heat in such a manner as two dots at each time, skipping two others. Subsequently, if head impressing voltage is supplied to feeding electrodes 10a2, 10a4,... exothermic resistors 83, 84, 87, 88,... become ready for printing, and by selection of feeding electrodes 10b1, 10b2, 10b3, 10b4 optional dots can be made to generate heat. By repeating the above a printing of one line is made feasible.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a thin film thermal head that can achieve high resolution.

(Prior Art) FIG. 1 shows a cross-sectional structural diagram of a medium-thin film thermal head according to a first embodiment of the prior art. In the same figure, 1 is glaze,
2 is a heating resistor, 3 is a power supply electrode, 5 is a protective film, and 7 is an alumina substrate. In this embodiment, the power supply electrode 3 on the upper surface of the heat generating resistor 2 is made thin to improve the contact between the heat generating resistor 2 and the thermal paper. However, the high-resolution thermal head has a drawback that the length of the heating dot, that is, the contact area between the thermal paper and the heating resistor 2 is small, and the paper contact becomes worse. Figure 2 shows heating resistor 2 and thermal paper 6.
Figure 2 (,) shows the case where the contact area of the heating resistor 2 is large, and Figure 2 (b) shows the state of contact with the paper.
shows the case where the contact area of the heating resistor 2 is small. As is clear from the figure, paper contact becomes worse when the resolution is made finer, and paper contact becomes better when the power supply electrode 3 is made thinner.

FIG. 3 shows the cross-sectional area of a conventional thin film thermal head according to a second embodiment. In this case, the glaze 1 is provided in a convex shape on the substrate, and the heating resistor 2, the power supply electrode 3, and the protective film 5 are provided on the glaze 1, and the paper 3p between the heating resistor 2 and the thermal paper is improved. However, it had the disadvantage that the structure was more complicated than that shown in FIG.

FIG. 4 shows a third conventional embodiment,
FIG. 4(a) is an external view of a thick film thermal head, showing that power supply electrodes 3 are alternately formed on heating resistors 2,
FIG. 4(b) shows a sectional view taken along the dashed line AA' in FIG. 4(a). When this method is applied to a thin film thermal head, the through hole shown in FIG. 5, the external view in FIG. 5(a), and the cross-sectional view in FIG.
In the cross-sectional view at 1), power supply electrodes are alternately formed on the upper part of the heating resistor 2. In this case, since the power supply electrode 3 is formed on the heating resistor 2, there is a drawback that poor paper contact υ occurs.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to obtain a thin-film thermal head capable of achieving high resolution with excellent adhesion between the heat-generating portion and the heat-sensitive recording paper.

(Structure of the Invention) The present invention provides a plurality of parallel-connected two heat-generating resistors with a gap between them via a non-heat-generating resistor to one electrode to which a voltage is applied. The other end of the one heat generating resistor connected to the electrode and the other end of the other heat generating resistor connected to the adjacent one voltage application electrode are connected to drive electrodes via non-heat generating resistors, respectively. connect to,
The thin film thermal head is characterized in that the drive electrodes are selectively driven by different drivers.

(First Embodiment) FIG. 6 is a pattern diagram of a thin film resistor and a power supply electrode showing a first embodiment of the present invention. '81. ....

86', -... are heating resistors, 9m, 9m1. -r9
&3r... and 9b, 9b1. ..., 9b4.
... is a non-heating resistor, 10 a, l Oa I
, −” + 10 a 3+ ”’ and 10 b
, 10 b 1 , Li, J Ob 4 , ・
... is a power supply electrode. The power supply electrode 10al is connected to the non-heat generating resistor section 9a, and there are two heat generating resistors 81.
82. Further, the heat generating resistor 82 is connected to the power supply electrode 10b2 through the non-heat generating resistor portion 9b2 together with the heat generating resistor 83 connected to the power supply electrode 10a2 adjacent to the power supply electrode 10al. Similarly, the power supply electrode 10
a2 is connected to the non-heat generating resistor portion 9a2, and from here to the two heat generating resistors 83 and 84. Also, heating resistor 84
through the non-heat generating resistor portion 9b3 together with the heat generating resistor 85 connected to the power supply electrode 10a3 adjacent to the power supply electrode 10a2,
This is connected to the power supply electrode 10b3. Similarly, power supply electrodes 10a, 10b, non-heating resistance parts 9m, 9b,
Heat generating resistors 8 are arranged. In such a structure, the voltage applied to the head is applied to the power supply electrode 10 a I + I
When applied to Oa J r I Oa 5+ '..., the heating resistors 81, 82, 85, 86... can be printed, and the power supply electrodes 10bl, 10b2°10b3. . . . can generate heat at any two dots every two dots by the switching elements connected to the dots. (In this case, depending on the selection method of the power supply electrodes, it is not necessarily necessary to drive two dots consecutively, but it is also possible to drive each dot independently.) Next, the voltage applied to the head is changed to the power supply electrodes 10a2, 10a4.
When applied to r..., heating resistors 83, 84, 87°8
8, . . . can be printed on the power supply electrode 10bl.

By selecting 10b2, 10b3, 10b4, any de,
I can get a lot of heat. By returning this, one line printing becomes possible. FIG. 7 is an equivalent circuit diagram of the thin film thermal head shown in FIG. 6, rl p r2 r −
r2n corresponds to the heating resistors 81, 82°, etc. in Fig. 6, Dil % Din41 is the backflow prevention diode, D
rl to Dry are the power supply electrodes 10b 1 and 10 in FIG.
This is a driver connected to b2. The head voltage is applied to the terminal COM-1, and the driver Drl=Drnt”
By selectively driving, the heating resistors rl to r2nk can be made to generate heat independently every two dots or one dot at a time. Next, by applying a voltage to the terminal COM-2 and selectively driving the drivers Dr1 to Drn, the remaining heating resistors are set every 2 dots or every 2 dots.
It is possible to generate heat independently one by one. In the case of this embodiment, current also flows into the heating resistor that is not driven.
This is not a problem because it does not generate enough heat to cause color development.

As explained above, in the thin film thermal head according to this embodiment, the non-heat generating resistor portions 9a and 9b are provided for the two independent heat generating resistor dots, so when the non-heat generating resistor is not provided. The distance between the power supply electrodes can be increased compared to the conventional method, and the adhesion between the heat-sensitive recording paper and the heating resistor can be improved. It is also possible to generate heat independently one dot at a time by selecting a driver.

Therefore, by using the thin film thermal head according to this embodiment, high resolution printing becomes possible.

(Other Embodiments) FIG. 8 shows a diagram of a thin film thermal head according to another embodiment of the present invention. This is a turn diagram, and is the same as that in FIG. 6 except that the heating resistor 8 is made thinner and meandering. By configuring the heating resistor in such a shape, it is possible to increase the resistance value and the heating temperature, thereby making it possible to color the thermal paper more clearly. Also in this example,
Figure 6.

The same effects as the first embodiment described with reference to FIG. 7 can be obtained.

Further, in FIG. 9, a voltage is selectively applied to the drivers Dry', Dr2', . . .
This is an embodiment in which the heating element is driven by . . . , and driving transistors are provided on both electrodes for selective driving.

Even if ν is used in this embodiment, the same effects as in the above-mentioned embodiments are obtained.

(Effects of the Invention) As explained above, the present invention provides one non-heating resistor portion for two independent thin-film heating resistor dots, so it is possible to widen the distance between the power supply electrodes and connect the heat-sensitive recording paper to the heat-generating resistor. This has the advantage that the adhesion between the resistors is improved and a high-resolution thermal head can be realized. Furthermore, the pitch at which the power supply electrodes are formed is one for every two dots of the heating element.Is it possible to implement the drive I10? The cutting bit is doubled, and the pattern width of the power supply electrode is also doubled.
Since it is twice as large, the yield is good and it has great advantages in terms of manufacturing.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional structural diagram of a thin film thermal head according to a first embodiment of the conventional technology. FIG. FIG. 4 is an explanatory diagram of a conventional thick film thermal head, and FIG. 5 is a cross-sectional structure of a thin film thermal head according to a third conventional example. 6 is a pattern diagram of a thin film thermal head showing the first practical example of the present invention, FIG. 7 is an equivalent circuit diagram of the thin film thermal head shown in FIG. 6, and FIG. 8 is a pattern diagram of a thin film thermal head shown in FIG. FIG. 9 is an equivalent circuit diagram of a thin film thermal head according to another embodiment of the present invention. 8, 81-86, ... heating resistor, 9a, 9
a1-9 a 3.9 b, 9 b nor 9b 4.
-El+heating resistor, lOa, 10al-10a, 1.
10b, 10bl to 10b4...power supply electrode, Di l
-Dil+4・Reverse current prevention diode, rl-r2n”
'Heating resistor, Dr□~Drn. Dr1~Dr Hisubi...driver. Patent applicant Oki Electric Industry Co., Ltd. Figure 6 Figure 7 Figure 8 Figure 9 Procedural amendment (voluntary) 1 Indication of the case 1981 Patent M No. 001379 3, Person making the amendment Relationship with the case Patent Applicant address (105) 1-7-12 Toranomon, Minato-ku, Tokyo
Address (105) 1-7-1 Toranomon, Minato-ku, Tokyo
No. 2 Figure 9

Claims (3)

[Claims] (1) A plurality of two heat generating resistors connected in parallel with a gap between one electrode to which a voltage is applied via a non-heat generating resistor are provided in parallel, and each of the above voltage applying electrodes is connected to the The other end of one heat generating resistor and the other end of the other heat generating resistor connected to the one voltage application electrode adjacent to each other are connected to a drive electrode via a non-heat generating resistor, and the drive A thin film thermal head characterized in that each electrode is selectively driven by a different driver. (2) The thin film thermal head according to claim 1, wherein the voltage application electrodes are connected every other time and voltage is applied alternately. (3) The thin film thermal head according to claim 1, wherein a voltage is selectively applied to each of the voltage application electrodes.