JP2945192B2 - Edge type thermal head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an end face type thermal head suitably used for a thermal type or thermal transfer type printer, facsimile or the like.

[0002]

2. Description of the Related Art Conventionally, as a thermal head used for a printer, a facsimile or the like, a flat thermal head in which a portion provided with a driver IC for driving and a heating resistor portion are provided on the same main plane of a substrate, JP-A-60-80
No. 81, Japanese Unexamined Patent Publication No. 61-40168, etc., an end-face type thermal head having a heating resistor provided on an end face of a substrate has been put to practical use.

[0003] In particular, the end-face type thermal head has better contact properties of the heat-generating resistor portion with the thermal paper or film as compared with the flat-type thermal head, and has an escape for avoiding contact between the drive circuit and the platen. There is no need to provide such a device, and it is recognized that the device has various advantages such as easy downsizing of the entire device and easy securing of the flatness of the portion where the heating resistor is provided.

However, in such an end face type thermal head, in order to improve the recording quality of printing or printing, the distance between the recording electrode for electrically connecting the heating resistor and the return electrode is made uniform. When the substrate located between the electrodes is made of a thin plate that can meet such demands, it is extremely difficult to handle such a thin plate during head manufacturing. It is difficult and the mechanical strength cannot be sufficiently secured. Furthermore, such a conventional end-face type thermal head employs a structure in which the heat-generating resistor portion protrudes from the base supporting the entire head toward the thermal paper or film. In many cases, it is difficult to quickly radiate the heat to the base or the like after the use of the heat for printing, so that dot blur, tailing, etc. occur, and the recording quality is not sufficiently satisfactory. Still further, an end-face type thermal head using a substrate having a thin-plate portion at the front end and forming a heating resistor at the thin front end has been considered, but in a head employing such a configuration, Has a problem in that the mechanical strength of the thin portion of the substrate at the head end portion remains, especially when the pressure of the head on the film or the thermal paper is high, such that the mechanical strength cannot be sufficiently secured. .

[0005]

Here, the present invention has been completed in view of the above-mentioned circumstances, and the problem to be solved is that the contact of the heat-generating resistor with the heat-sensitive paper or film is improved. An object of the present invention is to provide a high-quality, highly reliable, long-life end face type thermal head which is improved, has excellent heat response, and can maintain sufficient mechanical strength at the head end.

[0006]

According to the present invention, in order to solve such a problem, a heating resistor, a recording electrode and a return electrode connected to energize the heating resistor, and supporting the electrodes are provided. A ceramic substrate, wherein the ceramic substrate is a glass ceramic.
Contains glass, free-cutting glass ceramic, or mica
Comprised of free-cutting glass ceramic, and the ceramic
At the front end of the substrate, a third plane or a curved surface extending from one of the two main planes to gradually approach the other main plane and reaching the end face is reduced in thickness, and at least the thin front end is formed. The gist of the present invention is an end face type thermal head characterized in that the heating resistor is provided in a part including a part of the end face.

In the present invention, the end surface of the thin front end portion of the ceramic substrate is constituted by a plane in which the angle between the extension surface and the other main plane is less than 90 °, or is a curved surface. Or be composed.

In the above-mentioned ceramic substrate, it is desirable that at least a corner connecting a flat end face and a third plane or the other main plane is formed as a curved surface at a thin end portion thereof. .

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, in order to clarify the present invention more specifically, some embodiments of the present invention will be described in detail with reference to the drawings.

First, FIGS. 1 to 5 each show an example of an end face type thermal head according to the present invention. In these figures, a ceramic substrate 2 has a connecting surface 10 at a tip end extending from a first main plane 4 to a second main plane 6 gradually toward a second main plane 6 to an end face 8. It is considered to be thin. A large number of stripe-shaped recording electrodes 12 are provided on the second main surface 6 of the ceramic substrate 2, and the surface shapes are formed on the first main surface 4 and the connection surface 10. Are provided, and the electrodes 12 and 14 are respectively supported on the ceramic substrate 2. Further, a heating resistor 16 is provided on the end surface 8 of the thin front end portion of the ceramic substrate 2 so as to be electrically connected to the recording electrode 12 and the return electrode 14.

More specifically, in the end face type thermal head structure shown in FIG. 1, the connecting face 10 is formed as an inclined face to connect the first main plane 4 to the flat end face 8, and the end face is formed. A heating resistor 16 is formed on 8. In the structure of FIG. 2, the connecting surface 10 is a curved surface, connects the first main plane 4 and the flat end face 8, and the heating resistor 16 is formed on the end face 8. Have been. Further, in the structure shown in FIG. 3, the end face 8 shown in FIGS.
Is perpendicular to the second main plane 6,
The end surface 8 is inclined and intersects the second main plane 6, and the angle α formed by the extended surface and the second main plane 6 is less than 90 °. On the end face 8, a heating resistor 16 is formed. Further, the head shown in FIG. 4 has a structure in which a corner of a thin end portion of the head shown in FIG. 1 is rounded, and a connecting portion between a flat end face 8 and a connecting face 10 is provided. The connecting portions between the end face 8 and the second main plane 6 are both curved surfaces and are smoothly connected. Furthermore, FIG.
In this case, unlike the above examples, the end surface 8 has a curved surface as a whole, and has a structure in which the connecting surface 10 and the second main plane 6 are connected by a curved surface. The heating resistor 16 is formed thereon.

Therefore, in such an end face type thermal head, as shown in the figure, the heating resistor 16 is formed on the ceramic substrate 2 having a thin end portion, but the thin end portion is formed on the ceramic substrate. From the base side (the lower part in each figure) to the tip side (the upper part in each figure), the connection surface 10 consisting of a flat or curved surface continuously and gradually becomes thin, so that the heating resistance At the tip end where the body 16 is present, the substrate 2 is thin, so that good contact with the film or the thermal paper is obtained, and the heat generated by the heat generating resistor (16) is also low in the heat generation characteristics. It has the advantage of being effectively used for printing, and can also secure sufficient mechanical strength at the head end, and can sufficiently increase the pressure of the head against the film or thermal paper. Than it is.

In this end-face type thermal head, in FIGS. 1 and 2, the heating resistor 16 is formed on the end face 8 orthogonal to the main planes 4 and 6, but it is not always necessary to be so. Alternatively, it may be formed on the inclined end face 8 as shown in FIG. 3, or may be formed on the curved end face 8 as shown in FIG. Can be appropriately adopted.

Further, as shown in FIG.
When the heating resistor 16 is formed on a surface (8) that is not orthogonal to the above, if a so-called photolithography process is performed at the time of forming a pattern of the electrode 12 formed on the second main plane 6, the heating resistor 16 is collectively formed if necessary. This also has the advantage that the heating resistor 16 can be patterned at the same time. 4 and 5
As shown in FIG. 3, the connection between the end face 8 and the connection surface 10 or the second main plane 6 is a curved surface, or as shown in FIG. 3, the second main plane 6 on which the recording electrode 12 is formed. When the angle (= 180 ° −α) formed by the inclined end surface 8 is an obtuse angle, there is an advantage that defects such as disconnection of the pattern there are reduced, and the product yield is improved.

Further, in such an end face type thermal head, the heating resistor 16 needs to be provided at a thin portion at the tip end of the ceramic substrate 2, and the form thereof is as shown in FIG. , May be formed after the recording electrode 12 and the return electrode 14 are formed on the substrate 2, or as shown in FIGS.
Prior to the formation of the heat generating resistor 16,
And then the electrodes 12 and 14 are formed on the substrate 2, respectively, and any of them can be appropriately adopted.

The width d of the end face 8 of the ceramic substrate 2 where the heating resistor 16 is formed (thickness of the front end of the substrate): d depends on the printing or printing characteristics required at the front end of the head. In accordance with the present invention, the thickness is generally about 10 to 400 μm, preferably about 20 to 100 μm. That is,
If the width is smaller than 10 μm, the width of the heating resistor 16 formed thereon becomes narrow, and a good quality dot shape cannot be obtained. If the width is larger than 400 μm, a problem of heat storage in the heat generating portion occurs. In order to obtain high-quality recording, it is desirable to set the width in the above range.

Further, as the ceramic substrate 2 used for such an end face type thermal head, specifically,
Glass ceramic substrate, free-cutting glass ceramic substrate,
Or is free-cutting glass ceramic board containing mica can be mentioned <br/>, preferably the free-cutting glass ceramic substrate containing mica is used.

That is, since the tip of the ceramic substrate 2 is thin as described above, the heating resistor 1
6, when used for various recording methods, the heating resistor 16 is efficiently pressed against a film or a thermal paper, and the contact property is remarkably improved.
On the other hand, since the ceramic substrate 2 needs to have an appropriate heat storage property in order to efficiently concentrate the generated heat at a necessary portion, the heat storage property is not as small as that of alumina or aluminum nitride, and is smaller than that of glass. A free-cutting glass ceramic containing mica, which does not have a large heat storage property, is suitably used, whereby good heat generation response can be obtained, and further, recording quality can be improved. In addition, when machining is performed so that only a predetermined portion of the head tip becomes thin, the free-cutting glass ceramic substrate containing mica described above is excellent in machinability, and therefore easily has a high precision thin wall. A tip site can be formed.

As described above, a free-cutting glass-ceramic substrate suitable for heat storage and capable of easily obtaining a high-precision substrate surface by machining is used as the ceramic substrate 2 as described above. There is no need to provide a glaze layer that is inevitably provided between the heat generating resistor 16 and the cost can be advantageously reduced, and further, the heat generating resistor 16 due to the reaction between the heat generating resistor 16 and the glaze layer. This also has the advantage of avoiding the problem of shortening the life of the device.

In the end face type thermal head having the above structure, as shown in FIGS. 6 and 7, the thermal head is located at least at the tip end of the ceramic substrate 2 and is close to the heating resistor 16. So that a predetermined reinforcing member 18
May be installed. By arranging the reinforcing member 18 close to the heating resistor 16 in this manner, the mechanical strength of the thin portion at the head end portion is further improved. Furthermore, when the reinforcing member 18 is made of a material having excellent heat conductivity, the heat radiation characteristics of the heat generating resistor 16 are improved, and a good recording quality without dot blur, tailing or the like is obtained. is there.

The material constituting the reinforcing member 18 is more specifically selected from free-cutting alumina, free-cutting boron nitride, free-cutting aluminum nitride, brass, copper, aluminum, bronze and the like. Material whose main component is
Or a material obtained by combining them is preferably adopted, and among them, an easily wearable material mainly containing free-cutting alumina, free-cutting boron nitride, free-cutting aluminum nitride, and the like,
It is preferably used because it has excellent head slidability and heat dissipation. Further, in order to further improve the heat dissipation, the reinforcing member 18 provided in the vicinity of the heating resistor 16 is preferably provided so as to slide directly on the thermal paper or film.

According to the present invention, the heating resistor 16
To protect the electrodes and the electrodes 12, 14, etc.
Suitable insulating materials, such as silicon oxide, silicon nitride,
Using a material appropriately selected from silicon carbide, tantalum oxide, glass, and the like, it is also possible to provide the protective layer 20 at least at the tip of the head (see FIGS. 6 and 7). The prevention, wear resistance, insulation coating and the like can be effectively achieved. This protective layer 2
0 is provided according to a known method such as sputtering, CVD, or a thick film method, and may be not only a single-layer structure selected from the above materials but also a multilayer structure including the above materials, and When used for insulation coating of leads such as, organic materials, such as epoxy,
Phenol, polyimide and the like are advantageously used.

The recording electrode 12 and the return electrode 14 provided on the ceramic substrate 2 are each made of an ordinary conductor material. In particular, chromium, titanium, molybdenum,
Metals such as tungsten, nickel, gold, copper and the like, alloys containing them, nitrides, carbides, borides and the like of these metals are appropriately selected and used. Further, the recording electrode 12 and the return electrode 14 are formed on the respective main planes of the substrate 2 by the usual thin film method, the thick film method, or the like, using the electrode material as described above. The recording electrode 12 is usually patterned in accordance with the recording density of the head, while the return electrode 14 may be patterned in the same manner as the recording electrode 12, but is preferably provided as a common electrode. It is formed into a layer by a known appropriate method, or is joined as a plate-like electrode. The recording electrode 12 and the return electrode 14
Is selected to be at least 0.5 μm or more, preferably 1 μm or more, and more preferably 3 μm or more. It is also possible to provide a multilayer structure using the above-mentioned electrode material.

On the other hand, the heating resistor 16 provided on the thin portion at the tip of the ceramic substrate 2 is preferably a thin-film resistive film, a thick-film resistive film, or the like having high heat pulse characteristics and high resistance. , A material having a high melting point metal or its alloy as a main component, a material mainly containing a mixture of a high melting point metal or its alloy and any of oxides, nitrides, borides and carbides, or titanium, tantalum, chromium, Zirconium, hafnium, vanadium, lanthanum, molybdenum,
A material mainly composed of nitride, carbide, boride, silicide or the like of at least one element selected from tungsten and the like,
A material containing a ruthenium-based oxide as a main component or the like is appropriately adopted. And such a heating resistor 16
Are formed in a pattern according to the recording density of the head by a normal thin film method or the like, or are provided in a continuous single band shape.

The width (length in the left-right direction in each figure) of the heating resistor 16 does not need to be the same as the width d of the tip of the ceramic substrate 2; It can be made smaller or wider so as to cover the connection surface 10 and the second main plane 6.

In FIG. 6 showing another embodiment of the thermal head according to the present invention, a glaze layer 22 is formed on the front end face 8 and the second main plane 6 of the ceramic substrate 2.
Then, after the heating resistor 16 is provided on the front end surface 8, the recording electrode 12 is formed on the second main plane 6, and the return electrode 14 is formed on the connection surface 10 and the first main plane 4, respectively. An example of a thermal head having a structure in which a reinforcing member 18 is bonded to the outside of the head via an adhesive 24 and a protective layer 20 having a predetermined thickness is provided so as to cover the head end surface is shown. .

FIG. 7 shows another example of a thermal head according to the present invention having substantially the same structure as that of FIG. 6, but has an end face 8 having a slope which is not orthogonal to the second main plane 6. Slope, directly without the glaze layer 22,
This is an example in which a heating resistor 16 and a recording electrode 12 are formed on a ceramic substrate 2.

The specific configuration and embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to the above description, and the gist of the present invention is not limited. It should be understood that various changes, modifications, improvements, and the like can be made to the present invention based on the knowledge of those skilled in the art without departing from the present invention.

[0029]

As is apparent from the above description, the end face type thermal head according to the present invention has a third flat surface or a curved surface in which the thin front end portion of the ceramic substrate extends from the base side of the substrate toward the front end side. Because it is continuously thinned, it has good contact with thermal paper and film, excellent heat response, and sufficient mechanical strength at the head end. .

[Brief description of the drawings]

FIG. 1 is a perspective sectional view showing an example of an end face type thermal head according to the present invention.

FIG. 2 is an explanatory sectional view showing another example of the end face type thermal head according to the present invention.

FIG. 3 is an explanatory cross-sectional view showing another example of an end face type thermal head according to the present invention;

FIG. 4 is an explanatory sectional view showing still another example of the end face type thermal head according to the present invention.

FIG. 5 is an explanatory sectional view showing another example of the end face type thermal head according to the invention.

FIG. 6 shows an end face type thermal head according to the present invention.
It is sectional explanatory drawing which shows an example in which the protective layer was further provided on the heating resistor.

FIG. 7 shows an end face type thermal head according to the present invention.
It is sectional explanatory drawing which shows another example in which the protective layer was further provided on the heating resistor.

[Explanation of symbols]

 Reference Signs List 2 ceramic substrate 4 first main plane 6 second main plane 8 end face 10 connection plane (third plane or curved surface) 12 recording electrode 14 return path electrode 16 heating resistor 18 reinforcing body 20 protective layer 22 glaze layer 24 bonding Lumber

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 2/335

Claims (7)

(57) [Claims] 1. A thermal head comprising: a heating resistor; a recording electrode and a return electrode connected to energize the heating resistor; and a ceramic substrate that supports the electrodes. Glass ceramic, free-cutting glass
Free cutting glass containing mica or mica
The ceramic substrate is thinned by a third plane or a curved surface extending from one of the two main planes to the other main plane at the front end portion of the ceramic substrate and gradually reaching the end surface. An end face type thermal head, wherein the heat generating resistor is provided at a portion including at least a part of the end face at a thin end portion thereof. 2. The ceramic substrate according to claim 1, wherein an end surface of the thin front end portion of the ceramic substrate is formed by a plane in which an angle formed between an extended surface thereof and the other main plane is less than 90 °. The end face type thermal head as described. 3. A thin-walled front end of the ceramic substrate, wherein at least a corner connecting the end face to the third plane or the other main plane is formed as a curved surface. Item 3. An end face type thermal head according to item 1 or 2. 4. The end face type thermal head according to claim 1, wherein an end face of the thin front end portion of the ceramic substrate is formed as a curved surface. 5. At least a tip of said ceramic substrate
And a predetermined distance so as to be close to the heating resistor.
5. The reinforcing member according to claim 1, further comprising:
An end-face type thermal head according to any one of the above. 6. The reinforcing member is made of a material having excellent thermal conductivity.
6. The end face type thermal head according to claim 5,
De. 7. The reinforcing body is made of free-cutting alumina and free-cutting alumina.
Boron nitride, free-cutting aluminum nitride, brass, copper, aluminum
Mainly selected from the group consisting of minium and bronze
Material to be used for
The end face type sir according to claim 5 or 6, wherein
Mulhead.