JPH09174907A - Thermal head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out a high speed printing and, at the same time, the printing quality of a thermal head is improved. SOLUTION: High speed printing is carried out by improving heat responsiveness through a thinner glaze layer 25, which is made into a film in a thin film process. In the glaze layer 25, which is formed on the inclined plane 24 of a board 22 in the form of a film, a tapered part 26 is formed. A heating resistor element 30 is arranged on the glaze layer 25, which is formed on the inclined plane 24 in the form of a film. An individual electrode 31 is arranged on the glaze layer 25, which is formed on a board plane 23 in the form of a film. Further, a common electrode 32, one end of which connects with the heating resistor element 30 on the tapered part 26, is arranged so as not to project beyond the heating resistor element 30. Thus, even when the glaze layer 25 on the inclined plane 24 is made thinner, the heating resistor element 30 projects much beyond the common electrode 32 and the individual electrode 31, resulting in improving the pressing state of the heating resistor element 30 against a platen and consequently improving the printing quality of a thermal head.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to a thermal head.

[0002]

2. Description of the Related Art In recent years, as a structure of a thermal head used in a thermal printer, it is known that an inclined surface is formed on one end side of a substrate and a heating resistance element is disposed on this inclined surface. Japanese Patent Laid-Open No. 3-227660.
JP-A-2-202457, JP-A-2-99342
No. 6,009,036.

As shown in FIGS. 5 and 6, the thermal head disclosed in Japanese Patent Laid-Open No. 3-227660 has a glaze layer 2 on almost the entire surface of an insulating substrate 1 made of ceramics or the like.
Is formed, and the glaze layer 2 is etched to form the inclined surface 3
And a folded electrode 5 for connecting a large number of heat generating resistance elements 4 and two adjacent heat generating resistance elements 4 on the inclined surface 3.
And are arranged. The common electrode 6 and the individual electrode 7 are provided on the flat surface of the glaze layer 2 which is not etched, and the protective layer 8 is formed at the position where the heating resistance element 4 and the electrodes 5 to 7 are covered.

As shown in FIG. 7, the thermal head disclosed in Japanese Unexamined Patent Publication No. 2-202457 has an inclined surface 9a formed at the end of a substrate 9 made of ceramics or the like.
The glaze layer 10 is formed on the surface of the flat surface 9 b of the substrate 9. The heating resistor element 11 and the common electrode 12 are provided on the glaze layer 10 formed on the inclined surface 9a, and the individual electrode 13 is provided on the glaze layer 10 formed on the flat surface 9b.

As shown in FIG. 8, the thermal head disclosed in Japanese Patent Laid-Open No. 2-99342 forms a glaze layer 15 on the surface of a substrate 14 made of ceramics or the like. The end portion of this glaze layer 15 is patterned by a photolithography method and etched to form "θ1".
Forming an inclined surface 16 inclined at an angle of .theta., And thereafter, the end portion of the substrate 14 is ground by a diamond blade or the like so as to include the inclined surface 16 and inclined at an angle of .theta.2. Form 17. The heating resistance element 18 is provided on the inclined surface 16, the common electrode 19 is provided on the electrode inclined surface 17, and the individual electrode 20 is provided on the flat surface of the glaze layer 15 which is not etched. Heating resistor element 1
A protective layer 21 is formed at a position that covers 8 and the common electrode 19 and the individual electrode 20.

According to the thermal heads disclosed in the above publications, the pressing state between the heating resistance elements 4, 11, 18 and the platen for backing up the recording paper is improved, and the printing quality is improved. Especially in the thermal head of FIG.
Since the heating resistance element 18 is in a state of protruding more than the common electrode 19 and the individual electrode 20, the pressing state between the heating resistance element 18 and the platen is the best.

[0007]

However, in the thermal head shown in FIG. 8, the inclined surface 16 on which the heating resistance element 18 is installed is used.
The distance "S" is determined by the thickness of the glaze layer 15 and the inclination angle of the inclined surface 16. When the glaze layer 15 is thinned in order to improve the thermal response and operate the thermal head at high speed, The distance "S" of the inclined surface 16 becomes short, and it becomes impossible to manufacture a thermal head having a desired resolution. For example, if the glaze layer 15 is 2
Assuming that the inclination angle “θ1” of the inclined surface 16 is 10 °, the distance “S” of the inclined surface 16 is about 86 μm.
The size is as small as necessary to manufacture a thermal head of 0 dpi (1 pixel length is 85 μm). Therefore,
It is not possible to make the glaze layer 15 thinner than the above size to improve the thermal response, or to increase the inclination angle of the inclined surface 16 to further increase the protruding state of the heating resistance element 18.

Further, in the thermal head of FIG. 8, the inclined surface 16 is formed by etching, and the inclined surface 1 for the electrode is used.
Since 7 is ground with a diamond blade or the like, the manufacturing method is complicated.

In the thermal heads of FIGS. 5 and 6, since the heating resistance element 4 and the folding electrode 5 are arranged on the inclined surface 3, the heating resistance element 4 is not projected to the folding electrode 5. Absent.

The glaze layers 2, 10, 15 formed on the substrates 1, 9, 14 are generally formed by a thick film printing method. However, according to this thick film printing method, it is difficult to form a thin and uniform film. FIG.
When the glaze layer 10 is formed on the flat surface 9b and the inclined surface 9a as shown in FIG. 2 by the thick film printing method, when the printed glaze layer 10 is baked at a high temperature, the glaze layer 10 is likely to be curved in a convex shape, In particular, the inclined surface 9a is easily bent. When the heating resistance element 11 is disposed on the curved glaze layer 10 as described above, there is no problem when the heating resistance element 11 is located at the apex of the curve, but when it is deviated from the apex,
The pressing state of the heating resistance element 11 and the platen will be defective. Further, as the glaze layer 10 becomes thinner, the glaze layer 10 may be pulled by surface tension at the boundary between the flat surface 9b and the inclined surface 9a of the substrate 9 to cause a crack. When such a crack is formed, a short circuit is caused between the individual electrode and the common electrode (the substrate itself) when a substrate having a good electrical conductor is used.

Therefore, according to the present invention, by forming the glaze layer in a thin film process, the glaze layer can be made thinner, and the inclined surface can be flattened, so that high speed and high print quality can be achieved. Provided is a thermal head capable of further improving print quality by causing a heating resistance element to largely protrude from a common electrode or an individual electrode.

[0012]

DISCLOSURE OF THE INVENTION The present invention is directed to a substrate of an electrically good conductor having an inclined surface obliquely intersecting the substrate plane formed on one end side, and a thin film formed on the inclined surface of the substrate and the substrate plane. The glaze layer formed in the step, the taper portion obtained by etching the glaze layer on the inclined surface toward the one end side of the substrate, and the exposure exposing the inclined surface at the tip side of the tapered portion. Section, a heating resistor element provided on the glaze layer formed on the inclined surface, and one end of the heating resistor element provided on the glaze layer formed on the substrate plane. A connected individual electrode; a common electrode having one end connected to the heating resistance element on the tapered portion and the other end connected to the exposed portion so as not to project from the heating resistance element; Individual electrode and above And a protective layer covering said heat-generating resistor element and through electrode. Since the glaze layer is formed in a thin film process, the glaze layer can be thinly formed, and the occurrence of the curvature or the crack of the glaze layer can be prevented as compared with the case of forming the glaze layer by the thick film printing method. Moreover, since the tapered portion is formed and the heating resistor element and the common electrode are connected on the tapered portion and the individual electrodes are arranged on the glaze layer formed on the plane of the substrate, the glaze layer on the inclined surface is formed. Even if the thickness is reduced, the common electrode or the individual electrode does not protrude from the heating resistance element, and the pressing state of the heating resistance element against the platen or the like is improved. Since the common electrode is connected to the exposed portion of the inclined surface, sufficient current capacity can be secured without increasing the size of the substrate or thickening the common electrode.

[0013]

FIG. 1 shows a first embodiment of the present invention.
A description will be given based on FIG. SUS, Fe-Ni alloy, WC (tungsten carbide) as the main component and C
WC-Co cemented carbide containing Mo (cobalt), Mo,
The substrate 22 is formed of a metal material such as Kovar or a material having a good electrical conductivity such as a conductive ceramic material.
An inclined surface 24 that obliquely intersects the substrate plane 23 is formed on one end side of the substrate by polishing or the like.

After forming the inclined surface 24 on the substrate 22, the sputtering method, the plasma CVD method, the thermal CVD method, and the SOG (Spin o) are formed on the substrate plane 23 and the inclined surface 24.
A glaze layer 25 made of an insulating material such as SiOx is evenly formed to a thickness of 10 to 15 μm by a thin film process such as an n glass method.

After forming the glaze layer 25, the substrate 2
A resist film is formed on the second layer 2 by photolithography, and the glaze layer 25 on the inclined surface 24 is etched to form a tapered portion 26. Further, by this etching, the inclined surface 2 is formed on the tip side of the tapered portion 26.
4 is exposed to form an exposed portion 27. Taper part 26
As an etching method for forming the exposed portion 27 and the glaze layer 25 made of SiOx,
Wet etching using an etchant to a main component hydrofluoric acid, or dry etching using CF ₄ +0 ₂ such gases are suitable. These etchings are isotropic etchings, and if a film of 15 μm is isotropically etched, it is etched by about 15 μm in the lateral direction as well as in the thickness direction.

After the tapered portion 26 is formed on the glaze layer 25, BaRuOx, Ta-SiO ₂ or the like is sputtered on the glaze layer 25 including the tapered portion 26 to form a heating resistor layer 28. An electrode layer 29 is formed by sputtering Al or the like on top. After forming the heating resistor layer 28 and the electrode layer 29, patterning and etching are performed by photolithography to form the heating resistor element 30, the individual electrode 31, the common electrode 32, and the like. The heating resistor element 30 is disposed on the inclined surface 24, the individual electrode 31 is disposed on the glaze layer 25 formed on the substrate plane 23, and one end of the heating resistor element 30 is connected to the heating resistor element 30. Connecting. The common electrode 32 is disposed at a position including at least the tapered portion 26, and the heating resistor element 3 is provided.
It is arranged so as not to project from 0, one end side is connected to the heating resistance element 30, and the other end side is connected to the exposed portion 27.

After forming the heating resistance element 30, the individual electrode 31, the common electrode 32, etc., SiOx, Si
A protective layer 33 made of Nx or the like is formed.

In such a structure, in this thermal head, the glaze layer 25 is formed on the substrate plane 23 and the inclined surface 24 by the thin film process, so that the glaze layer 25 is formed.
It is possible to obtain a thermal head having excellent thermal response and capable of high-speed printing. Moreover, by forming the glaze layer 25 in the thin film process, it is possible to prevent the glaze layer 25 from being curved or split, which may occur when the film is formed by the thick film printing method. It is possible to prevent defective printing due to various curves and tears.

Regarding the manufacturing process of the thermal head, a glaze layer 25 is formed on the substrate plane 23 and the inclined surface 24, and the glaze layer 25 is etched to form the tapered portion 2.
6 is formed, a heating resistor layer 28 and an electrode layer 29 are formed on the glaze layer 25, and the heating resistor layer 28 and the electrode layer 29 are patterned and etched by a photolithography method. Then, the heating resistor element 30, the individual electrode 31, and the common electrode 32 are formed. Therefore, the thermal head shown in FIG. 8 does not need to be ground as described above, and the thermal head can be easily manufactured.

Moreover, a taper portion 26 is formed on the glaze layer 25 formed on the inclined surface 24, and the taper portion 26 is formed.
Since the heating resistance element 30 and the common electrode 32 are connected to each other and the individual electrode 31 is arranged on the glaze layer 25 formed on the substrate plane 23, the heating resistance element 30 is formed even if the glaze layer 25 is thin. 2 can be projected more than the common electrode 32 or the individual electrode 31, and as shown in FIG. 2, the pressing state of the heating resistance element 30 against the platen 34 and the like is improved, and the printing quality is also improved.

Since the other end of the common electrode 32 is connected to the exposed portion 27 of the inclined surface 24, the substrate 22 is connected to the common electrode 32.
Can be used as part of Therefore, it is possible to secure a sufficient current capacity without increasing the length of the inclined surface 24 in the common electrode 32 in the inclination direction or increasing the thickness of the common electrode 32, and the common electrode 32 on the substrate 22. It is not necessary to secure a large space for installing the board, and the substrate 22 can be downsized.

When printing is performed using a thermal isolation ribbon (not shown), the distance from the central portion of the heating resistor element 30 until the thermal stripping ribbon is peeled off is preferably several hundreds of μm or less, and is inclined. It is necessary to make the length of the surface 24 along the inclination direction very short. However, by connecting the common electrode 32 to the electrically conductive substrate 22, the inclined surface 2
Even if the length of 4 is made extremely small, the common electrode 32 can secure a sufficient current capacity, and the print quality is improved even when the ribbon for hot peeling is used.

Since the heating resistance element 30 and the common electrode 32 are connected at the position of the taper portion 26, even if a stepped recess is formed at the etching end point in the glaze layer 25, the recess is formed. Therefore, the disconnection of the common electrode 32 due to does not occur, and the reliability of the electrical connection portion between the heating resistance element 30 and the common electrode 32 becomes high. Moreover, the common electrode 3
By connecting 2 and the heating resistance element 30 on the tapered portion 26, the area of the heating resistance element 30 which is located on the tapered portion 26 and is not pressed by the platen 34 or the like is reduced, and the thermal efficiency can be improved. it can.

Next, a second embodiment of the present invention will be described with reference to FIG.
It will be described based on. The same parts as those in the above-described embodiment are designated by the same reference numerals, and only different points will be described (hereinafter the same). In this embodiment, the substrate main body 35 is made of an electric resistance material or an insulating material, and the electrically good conductor film 36 is formed on the surface of the substrate body 35 to form the electrically good conductor substrate 37. is there. The glaze layer 2 is formed on the substrate 37 in the same manner as in the above-described embodiment.
5, taper portion 26, heating resistance element 30, individual electrode 3
1, the common electrode 32 and the like are formed.

As the material of the substrate body 35, ceramics such as Al ₂ O ₃ is used, and as the electrically good conductor film 36, a metal having a low specific resistance such as Al, Mo, Au is desirable, and the glaze layer 25 is etched. It is important to have resistance to the etching solution used. The electrically good conductor film 36 may be formed on the entire surface of the substrate body 35,
Alternatively, the film may be formed only at a specific position including at least the inclined surface 24. The width and thickness of the electrically good conductor film 36 are set to a value that does not cause a voltage drop at the time of printing or a value that does not adversely affect the printing quality, depending on the resistance value and the number of the heating resistance elements 30.

Also in the thermal head of this embodiment, high-speed printing is possible, the printing quality is improved, and the manufacturing is easy, as in the above-mentioned thermal head.

Next, a third embodiment of the present invention will be described with reference to FIG.
It will be described based on. In the present embodiment, two layers of glaze layers 25a and 25b are formed on the substrate 22 having a good electrical conductor. After the two layers of glaze layers 25a and 25b are formed, the taper portion 26, the heating resistance element 30, the individual electrode 31, and the common electrode 3 are formed as in the above-described embodiment.
2 etc. are arranged.

To form the glaze layers 25a and 25b, the substrate 22 is placed in a thin film device to form a lower glaze layer 25a on the surface of the substrate 22, and the substrate 22 is once taken out from the thin film device and glaze is applied. The surface of the layer 25a is scrubbed. After that, the substrate 22 on which the glaze layer 25a has been formed is put into the thin film device again, and the glaze layer 25b is formed on the glaze layer 25a.

As described above, the two glaze layers 25a, 25
By forming b, it is possible to prevent a short circuit between the substrate 22 and the individual electrode 31 due to pinholes formed in the glaze layers 25a and 25b.

In this embodiment, the two glaze layers 25 are provided.
The description has been given by taking the case of depositing a and 25b as an example.
More than one layer may be formed, and by increasing the number of glaze layers to be formed, it becomes possible to more reliably prevent short circuits due to pinholes.

Regarding the material of the glaze layers 25a and 25b, the case where different materials are used has been described in the present embodiment, but the same material may be used. However, when different materials are used, the lower the glaze layer is, the more difficult it is to be etched. Thereby, even if the glaze layer is in a stepped state due to the difference in etching rate at the boundary, it is prevented that the lower glaze layer is etched more and the upper glaze layer is overhung. This prevents the common electrode 32 disposed on these glaze layers from breaking due to the overhang of the upper glaze layers.

[0032]

According to the present invention, by forming the glaze layer in the thin film process, the glaze layer can be made thinner and the inclined surface can be flattened, so that high speed and high print quality can be achieved. Moreover, the printing quality can be further improved by making the heating resistance element largely protrude from the common electrode or the individual electrode.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional side view showing a state in which a thermal head is pressed against a platen.

FIG. 3 is a vertical sectional side view showing a second embodiment of the present invention.

FIG. 4 is a vertical sectional side view showing a third embodiment of the present invention.

FIG. 5 is a vertical sectional side view showing a first conventional example.

FIG. 6 is a plan view showing an arrangement state of electrodes and heating resistance elements.

FIG. 7 is a perspective view showing a second conventional example.

FIG. 8 is a vertical sectional side view showing a third conventional example.

[Explanation of symbols]

 22, 37 substrate 23 substrate plane 24 inclined surface 25, 25a, 25b glaze layer 26 taper portion 27 exposed portion 30 heating resistance element 31 individual electrode 32 common electrode 33 protective layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Tsuchmoto 6-78 Minamimachi, Mishima City, Shizuoka Prefecture

Claims (1)

[Claims] 1. A substrate of an electrically good conductor having an inclined surface obliquely intersecting the substrate plane formed on one end side, and a glaze layer formed on the inclined surface and the substrate plane of the substrate by a thin film process. , A tapered portion obtained by etching the glaze layer on the inclined surface toward one end side of the substrate in a tapered shape, an exposed portion that exposes the inclined surface at a tip end side of the tapered portion, and a tapered portion on the inclined surface. A heating resistor element disposed on the formed glaze layer, an individual electrode disposed on the glaze layer formed on the substrate plane and having one end connected to the heating resistor element, and one end A common electrode connected to the heating resistance element on the tapered portion and connected to the exposed portion at the other end so as not to project from the heating resistance element, the individual electrode, the common electrode, and the common electrode. Heating resistor element And a protective layer that covers