JP3002582B2 - 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. It has been recognized that there is no need to provide, and it is more advantageous as it has various advantages such as easy miniaturization 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.

[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 an end face type thermal head which is improved, has excellent heat response, and has good recording quality.

[0006]

According to the present invention, in order to solve the above-mentioned problem, at least the tip portion of the ceramic substrate is made thin, a heating resistor is provided in the thin portion, and the heating resistor is energized. The recording electrode and the return electrode for performing the above are respectively supported by the ceramic substrate, and a radiator is provided so as to be located at least at the end of the ceramic substrate and close to the heating resistor. The gist is an end-face type thermal head characterized by the following.

In the present invention, the substrate is preferably formed of a free-cutting glass ceramic substrate containing mica.

In the present invention, it is preferable that the heat generating resistor is generally formed directly on the substrate without interposing a glaze layer.

[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 4 each show an example of an end face type thermal head according to the present invention. In these figures, the ceramic substrate 2 is formed so that at least its tip is thin, and on both main surfaces thereof, a large number of stripe-shaped recording electrodes 4 and one of the ceramic substrates 2. The return electrodes 6 provided corresponding to the main surface shape are respectively supported. Further, the end surface of the thin front end portion of the ceramic substrate 2 is electrically connected to the recording electrode 4 and the return electrode 6 so that
A heating resistor 8 is provided. In addition, in FIGS. 1 to 3, outside the main surface of the substrate 2 supporting the return electrode 6,
In this case, the heat radiator 12 is attached to the adhesive 10 so as to be positioned at least at the head end and close to the heating resistor 8 outside the main surface of the substrate 2 (2a) supporting the recording electrode 4.
, Thereby forming an integrated head structure.

In such an end face type thermal head, the heating resistor 8 needs to be provided at a thin portion at the front end of the substrate 2. After the return electrodes 6 are formed, they are provided so as to cover the tips of the electrodes 4 and 6 as shown in FIGS. 3, or prior to the formation of the electrodes 4 and 6, a heating resistor 8 is provided on the front end surface of the substrate 2 and then the electrodes 4 and 6 are connected to the substrate 2 as shown in FIG.
However, any configuration may be used, and any of them may be appropriately adopted.

Further, in such an end face type thermal head, the ceramic substrate 2 needs to have at least the head end portion (upper portion in each drawing) as shown in the drawing, and the ceramic substrate 2 has a whole shape. Is formed as a thin wall (FIG. 1), but a notch is formed at the front end by machining, press molding, or the like so that the head is thinned only by a predetermined length at the head end where the heating resistor is provided. Even if it is formed (FIGS. 2 and 3),
A thin-walled plate or green sheet (2a) and a thick-walled plate or green sheet (2b) are laminated or joined so that a predetermined length portion at the head end portion becomes thinner.
Any of these may be subjected to a heat treatment or the like as necessary and integrally formed (FIG. 4), and any of them may be employed. In FIGS. 2 and 3, the surface from the thick portion to the thin portion (cut portion) at the front end of the substrate 2 is an obliquely inclined surface, but is an acutely inclined surface. Alternatively, it may be a right-angled surface giving a stepped shape, or even a rounded surface.

The width of the portion of the ceramic substrate 2 where the heating resistor is formed (thickness of the tip of the substrate: for example, the length of the tip of the substrate 2 in the horizontal direction in FIG. 2) is required for the tip of the head. Depending on the printing or printing characteristics to be performed, it will be appropriately selected.
Approximately 400 μm, preferably approximately 20-100 μm is suitably employed. That is, if the width is smaller than 10 μm, the width of the heating resistor becomes short, and a good dot shape cannot be obtained. If the width is larger than 400 μm, the distance between the heating resistor and the radiator becomes large, and the heat generation becomes large. This is because there is a problem of heat storage in the part, and in order to obtain high-quality recording, it is desirable to set the width in the above range.

Specific examples of such a ceramic substrate 2 include a glass ceramic substrate, a free-cutting glass ceramic substrate, a free-cutting glass ceramic substrate containing mica, a zirconia substrate, and a glass substrate. However, preferably, a free-cutting glass ceramic substrate containing mica is used.

That is, since the substrate 2 has a thin end as described above, when the substrate 2 is used for various recording methods via the heating resistor 8, the heating resistor 8 becomes a film or a thermal paper. And the contact property is remarkably improved. On the other hand, in order to efficiently concentrate the generated heat on a necessary part, the substrate 2 is required.
Need to have a moderate heat storage,
Alumina, aluminum nitride, etc. does not have a small heat storage property, and the heat storage property is not as large as glass, and free-cutting glass ceramics containing mica are preferably used, whereby good heat generation response is obtained, The recording quality can be improved.

In addition, as shown in FIGS. 2 and 3, when machining is performed so that only a predetermined portion of the head end portion becomes thin, the above-mentioned free-cutting glass ceramic substrate containing mica is difficult to machine. Therefore, a high-precision thin-walled portion can be easily formed.

Further, as described above, by using a free-cutting glass ceramic substrate suitable for heat storage as the substrate 2 and capable of easily obtaining a high-precision substrate surface by machining, the substrate and the heating resistor are conventionally used. There is no need to provide a glaze layer, which was inevitably provided between the heating element and the substrate. This can advantageously reduce costs and avoid the problem of shortening the life of the heating element due to the reaction between the heating element and the glaze layer. It also has the advantage of being done.

By the way, in the thermal head having such a structure, a predetermined radiator 12 is provided so as to be located at least at the front end of the substrate 2 and to be close to the heating resistor. By disposing the heat radiator 12 close to the heat generating resistor 8, the heat radiating characteristics of the heat generating resistor 12 are improved, and a good recording quality without dot blur, tailing or the like can be obtained.

More specifically, as a material constituting such a radiator 12, free-cutting alumina, free-cutting boron nitride, free-cutting aluminum nitride, shinchu, copper,
A material mainly composed of a material selected from aluminum, bronze, or the like, or a material obtained by combining them is preferably used. Among them, free-cutting alumina, free-cutting boron nitride, free-cutting aluminum nitride, and the like are mainly used. Material
It is preferably used because it has excellent slidability and contact properties of the head. The radiator 12 provided in the vicinity of the heating resistor 8 has a heating resistor at a contact surface of the head with the thermal paper or film so as to directly contact the thermal paper or film in order to improve heat radiation. 8 is preferably installed on the same plane.

Further, in the thermal head having such a structure, advantageously, as shown in FIG. 5, the main portion of the substrate 2 is provided at least on the thin portion at the tip of the head where the heating resistor 8 is provided. On one side of the plane, a predetermined reinforcing material 14 is adhered via the adhesive 10 so as to conform to the shape of the substrate at the head end portion so as to reinforce at least the thin-walled portion at the head end portion. The reinforcing member 14 is preferably provided with a material having a lower hardness than the recording electrode 4 and the return electrode 6 and an easier wear than the heating resistor 8 or a protective layer (24) described later. in this case, although the that it easily abradable material is used than, in particular Knoop hardness of 1000 kgf / mm ² or less, more preferably 500 kgf / mm ² or less of metal, ceramic, glass, glass ceramics, etc. Materials are appropriately selected and used. Thus, the heating resistor 8 provided on the end face of the substrate 2 slides on the thermal paper or film,
It becomes a shape protruding slightly forward from the end face of the reinforcing material 14,
Both mechanical strength and contactability can be satisfied.

More specifically, as the easily wearable material constituting the reinforcing member 14, a free-cutting glass ceramic, a free-cutting glass ceramic containing mica, a free-cutting alumina, a free-cutting boron nitride, a free-cutting boron nitride, and the like. A material mainly composed of a material selected from aluminum nitride, brass, copper, aluminum, bronze, or the like, or a material obtained by combining them is preferably employed. Among them, a free-cutting glass ceramic containing mica, Machinable alumina, free-cutting boron nitride,
A material mainly containing free-cutting aluminum nitride or the like is preferably used because it has excellent head slidability and contact properties. In particular, a material mainly composed of free-cutting alumina, free-cutting boron nitride, free-cutting aluminum nitride, and the like is excellent in thermal conductivity, and therefore also has the role of the radiator 12 described above. By providing a reinforcing material made of a material that is easy to wear, heat radiation characteristics can be further improved.

As described above, in such a thermal head structure, by arranging the predetermined reinforcing member 14 at least at the front end portion of the head, when the thermal head is used, the reinforcing member 14 can be connected to a thermal paper or a film. The exfoliation or the like of the heating resistor 8 or the protective layer (24) due to the sliding contact is not caused, and the exfoliated material or the like is caught between the electrode and the thermal paper or the like, thereby causing a problem of obstructing printing or printing. Excellent characteristics are exhibited in that there is no occurrence.

The radiator 12 and the reinforcing member 14 as described above are used.
Alumina, as an adhesive 10 for attaching
An inorganic material containing silica, boron nitride, or the like, or a resin material containing epoxy, phenol, polyimide, or the like may be used, or a composite material containing the inorganic material and the resin material may be used. Among them, inorganic materials including alumina, silica, boron nitride and the like are suitably selected.

In the present invention, in order to protect the heating resistor 8 and the electrodes 4, 6, etc., if necessary, a suitable insulating material such as silicon oxide, silicon nitride, silicon carbide, Using a material appropriately selected from tantalum oxide, glass and the like, at least a protective layer 24
(See FIGS. 13 to 15), and the protective layer 24 can effectively prevent oxidation, abrasion resistance, insulation coating, and the like. The protective layer 24
Is provided according to a known method such as sputtering, CVD, and a thick film method, and may be not only a single-layer structure selected from the above materials, but also a multilayer structure made of the above materials, When used for insulation coating of such leads, organic materials such as epoxy, phenol, and polyimide are advantageously used.

Further, in the thermal head according to the present invention, as shown in FIG. 6, an electric insulating layer such as glass, so-called Is provided, and the recording electrode 4 and the return electrode 6 are supported thereon. Thereby, the heat diffusion in the heating resistor 8 is slowed down, and the resistor 8 can be more firmly joined to the substrate 2.

The recording electrode 4 and the return electrode 6 provided on the substrate 2, respectively, are made of a normal conductor material, and particularly, chromium, titanium, molybdenum, tungsten,
It is appropriately selected from metals such as nickel, gold, copper and the like, alloys containing them, nitrides, carbides, borides and the like of these metals. Further, the recording electrode 4 and the return electrode 6 are formed on each main plane of the substrate 2 by the usual thin film method or thick film method using the electrode material as described above. The recording electrode 4 is usually patterned in accordance with the recording density of the head, while the return electrode 6 may be patterned in the same manner as the recording electrode 4, 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-shaped electrode. The thickness of the recording electrode 4 and the return electrode 6 is selected to be at least 0.5 μm or more, preferably 1 μm or more, and more preferably 3 μm or more, and provided as a multilayer structure using the above electrode material. Can be
It is possible.

On the other hand, the heating resistor 8 provided at the thin portion at the tip of the substrate 2 is preferably a thin-film resistance film, a thick-film resistance film, or the like having high heat resistance pulse characteristics and high resistance. A material mainly composed of a high melting point metal or its alloy, a material mainly composed of 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 a nitride, carbide, boride, silicide or the like of at least one element selected from tungsten, a material mainly composed of a ruthenium-based oxide, and the like. It will be adopted appropriately. Then, such a heating resistor 8 is formed in a pattern according to the recording density of the head by a normal thin film method or the like, or provided in a continuous single band shape.

By the way, as shown in FIGS. 1 to 6, the substrate surface of the thin portion located at least at the front end of the substrate 2 on which the above-mentioned heating resistor 8 is formed does not necessarily have to support the electrodes 4 and 6 (a so-called surface). The plane does not need to be orthogonal to the main plane (so-called end face), and may be an oblique plane to the main plane or a curved surface that is continuously curved from the main plane as shown in FIGS. Good. Furthermore, as shown in FIG. 9, even if the end connecting the surface mainly supporting the electrodes 4 and 6 and the surface mainly supporting the heating resistor 8 is connected by a curved surface having R, There is no problem, and any of them can be appropriately adopted.

Further, various other embodiments according to the present invention are shown in FIGS. 10 to 15, respectively, wherein FIG. 10 first shows that the recording electrode 4 has the glaze layer 16 as in the previous example. While the return electrode 6 is provided on the other main plane of the substrate 2 via the glaze layer 16 so as to be located only at the head end, and An example is shown in which a thermal head having a structure in which a reinforcing member 14 and a radiator 12 are provided on the recording electrode 4 and the return electrode 6 via an adhesive 10 respectively is used. Then, the head having such a structure is connected to the mounting substrate 18 by the lead 2.
6 is connected to the return electrode 6 via an adhesive 10 so as to be mounted.

FIG. 11 shows that the recording electrode 4 is supported on one principal plane of the substrate 2 via a glaze layer 16 and the common electrode (return electrode) is disposed on the other principal plane via an adhesive 10. ) Is an example of a thermal head having a structure in which an electrode plate 20 having a predetermined thickness is laminated.
Also has a role as a heat sink and a reinforcing plate,
An insulating plate 22 is provided outside the electrode plate 20. Further, FIG. 12 shows an example in which the recording electrode 4 and the return electrode 6 are respectively formed on the opposing main plane of the substrate 2 after the heating resistor 8 is provided at the tip of the substrate 2. A reinforcing member 14 and a radiator 12 similar to those in FIG. 10 are integrally provided on the recording electrode 4 and the return electrode 6.

FIGS. 13 to 15 show, respectively,
An example in which a suitable protective layer 24 is further provided on the heating resistor 8 is shown. That is, FIG. 13 shows that the electrodes 4 and 6 are provided on both main planes of the substrate 2 with the glaze layer 16 interposed therebetween, and further outside the reinforcing member 1 with the adhesive 10 interposed therebetween.
FIG. 14 shows an example in which a heat radiator 12 is provided, a heating resistor 8 is formed on a head end face, and a protective layer 24 having a predetermined thickness is provided so as to cover the head end face.
After the electrodes 4 and 6 are formed on the substrate 2, the heating resistor 8 and the protective layer 24 are sequentially formed.
FIG. 15 shows an example in which the reinforcing members 14 are provided, and FIG. 15 shows that after the electrodes 4 and 6 are provided on both main planes of the substrate 2, the heating resistor 8 and the protective layer 24 are sequentially formed only on the end surfaces thereof. And a reinforcing member 14 and a radiator 1 outside the two main planes of the substrate 2, respectively.
2 is provided.

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.

[0033]

As is clear from the above description, in the end face type thermal head according to the present invention, at least the tip of the ceramic substrate is made thin, and the heat generating resistor is provided on the thin portion. Since the recording electrode and the return electrode for energizing the heating resistor are supported by the substrate, the contact of the heating resistor with the thermal paper or film is good, and the heating response is excellent. In addition, since the printing quality can be advantageously improved, and a predetermined heat radiator is provided at the tip (thin portion) of such a ceramic substrate, it can be used for printing or printing. The radiated heat is quickly radiated, so that good quality without dot blur and tailing can be obtained in high-speed printing or printing.

[Brief description of the drawings]

FIG. 1 is a perspective 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 still another end face type thermal head according to the present invention.

FIG. 4 shows an end face type thermal head according to the present invention.
It is sectional explanatory drawing which shows an example in which the board | substrate was made into the laminated structure.

FIG. 5 is an end face type thermal head according to the present invention;
FIG. 4 is an explanatory cross-sectional view showing an example in which a reinforcing material is provided on one surface of a main plane of a substrate.

FIG. 6 shows an end face type thermal head according to the present invention.
It is sectional explanatory drawing which shows another example in which the reinforcement was provided in one surface of the main plane of the board | substrate.

FIG. 7 shows an end face type thermal head according to the present invention.
FIG. 4 is a cross-sectional explanatory view showing an example in which a substrate surface located at a tip is not a surface orthogonal to a main plane.

FIG. 8 is an end face type thermal head according to the present invention;
FIG. 9 is a cross-sectional explanatory view showing another example in which the substrate surface located at the tip is not a surface orthogonal to the main plane.

FIG. 9 shows an end face type thermal head according to the present invention.
It is sectional explanatory drawing which shows another example from which the board | substrate surface located in a front-end | tip part is not a surface orthogonal to a main plane yet another example.

FIG. 10 is an explanatory cross-sectional view showing an example in which the return electrode is provided so as to be located only at the head end portion on one main plane of the substrate in the end face type thermal head according to the present invention.

FIG. 11 is an explanatory sectional view showing an example in which a plate electrode is used as a return electrode in the end face type thermal head according to the invention.

FIG. 12 is an explanatory cross-sectional view showing an example in which a recording electrode and a return electrode are formed after a heating resistor is provided in the end face type thermal head according to the present invention.

FIG. 13 is an explanatory sectional view showing an example in which a protective layer is further provided on a heating resistor in the end face type thermal head according to the present invention.

FIG. 14 is an explanatory cross-sectional view showing another example in which a protective layer is further provided on the heating resistor in the end face type thermal head according to the present invention.

FIG. 15 is an explanatory cross-sectional view showing still another example in which a protective layer is further provided on a heating resistor in the end face type thermal head according to the invention.

[Explanation of symbols]

 2 Substrate 4 Recording electrode 6 Return electrode 8 Heating resistor 10 Adhesive material 12 Heat radiator 14 Reinforcement material 16 Glaze layer 20 Electrode plate 22 Insulating material 24 Protective layer 26 Lead

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B41J 2/335 H01L 49/00

Claims (3)

(57) [Claims] At least a tip portion of a ceramic substrate is made thin, and a heating resistor is provided on the thin portion.
While the recording electrode and the return electrode for energizing the heating resistor are respectively supported by the ceramic substrate, the recording electrode and the return electrode are located at least at the front end of the ceramic substrate,
An end face type thermal head is provided with a radiator so as to be close to the heating resistor. 2. The end face type thermal head according to claim 1, wherein the substrate is a free-cutting glass ceramic substrate containing mica. 3. The end face type thermal head according to claim 1, wherein the heating resistor is formed directly on the substrate.