JPH05525A - End face-type thermal head - Google Patents

Abstract

PURPOSE:To obtain an end face-type thermal head with improved contact properties of a heating resistor part with heat-sensitive paper and a film, a superior heat generation response, and a good recording quality. CONSTITUTION:At least a top end part of a ceramic substrate 2 is made to have a thin wall. Heating resistors 8 are provided on the thin wall part. Recording electrodes 4 and return electrodes 6 for passing an electric current to the heating resistors 8 are respectively supported on the ceramic substrate 21. On the other hand, a heat release body 12 is disposed at least on the top end part of the ceramic substrate 2 in proximity to the heating resistors 8.

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 suitable for use in a thermal type or thermal transfer type printer or facsimile.

[0002]

2. Description of the Related Art Conventionally, as a thermal head used in a printer, a facsimile, etc., a flat type thermal head in which a portion where a driver IC for driving is provided and a heating resistor portion are provided on the same main plane of a substrate, JP 60-80
No. 81, JP-A-61-40168, etc., an end surface type thermal head in which a heat generating resistor portion is provided on the end surface of a substrate has been put into practical use.

In particular, the end face type thermal head has better contact with the heat sensitive paper or film in the heat generating resistor portion than the flat type thermal head, and the escape for avoiding the contact between the drive circuit and the platen. It is recognized that it is more advantageous as it has various advantages such that it is not necessary to provide the device, the size of the entire device can be easily reduced, and the flatness of the portion where the heat generating resistance portion is provided can be easily ensured. ..

However, in such an end surface type thermal head, in order to improve the recording quality such as printing or printing, the distance between the recording electrode electrically connecting the heating resistor portion and the return electrode is uniform. However, when the substrate positioned between the electrodes is made of a thin plate that can meet such requirements, it is extremely difficult to handle such a thin plate when manufacturing the head. There was a problem that it was difficult and mechanical strength could not be sufficiently secured. Further, in such a conventional end face type thermal head, since the heat generating resistance portion has a structure protruding from the base supporting the entire head toward the thermal paper or film, the heat generating resistance portion is generated. In many cases, it is difficult to quickly dissipate the generated heat to the base after using it for printing, which causes dot blurring, tailing, etc., and the recording quality is not sufficiently good.

[0005]

The present invention has been completed in view of the above-mentioned circumstances, and the problem to be solved is that the contact resistance of a heat-generating resistor portion with a thermal paper or a film is high. It is an object of the present invention to provide an end surface type thermal head which is improved, has excellent heat generation response, and has good recording quality.

[0006]

In the present invention, in order to solve such a problem, at least a tip portion of a 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 heat radiator is provided so as to be located at least at the tip of the ceramic substrate and close to the heating resistor. An end face type thermal head, which is characterized in that

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

Further, in the present invention, it is generally preferable that the heating resistor is directly formed on the substrate without a glaze layer.

[0009]

Specific Structure / Examples In order to more specifically clarify the present invention, some examples 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 surface 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, one of the stripe-shaped recording electrodes 4 and one of the ceramic substrates 2 is formed. The return electrodes 6 provided corresponding to the main surface shape are respectively supported. Further, on the end face of the thin end portion of the ceramic substrate 2, so that the recording electrode 4 and the return electrode 6 can be electrically connected,
A heating resistor 8 is provided. It should be noted that in FIGS.
In the first embodiment, the heat radiator 12 is located outside the main surface of the substrate 2 (2a) that supports the recording electrodes 4 at least at the tip of the head and is close to the heating resistor 8.
The heads are attached to each other through the, thus forming an integral head structure.

By the way, in such an end surface type thermal head, the heating resistor 8 needs to be provided in the thin portion of the tip end portion of the substrate 2, and the form is as follows. After the return path electrode 6 is formed, the return path electrode 6 is provided so as to be electrically connected to the electrodes 4 and 6 as shown in FIGS. 3 or as shown in FIG. 3, a heating resistor 8 is provided on the tip surface of the substrate 2 prior to the formation of the electrodes 4 and 6, and then the electrodes 4 and 6 are attached to the substrate 2.
Even if it is a structure formed in each, it does not matter at all and any of them can be appropriately adopted.

Further, in such an end surface type thermal head, at least the head end portion (the upper portion in each figure) of the ceramic substrate 2 needs to be thin as shown in the drawing, and the shape thereof is the whole. However, even if it is formed as a thin wall (Fig. 1), a notched portion is formed at the tip by machining or press molding so that the wall is thin only at a predetermined length of the head tip where the heating resistor is provided. Even if it is formed (Figs. 2 and 3),
A thin plate or green sheet (2a) and a thick plate or green sheet (2b) are laminated or joined so that a predetermined length portion of the head tip portion becomes thin.
Any of them can be adopted even if they are integrally formed by performing heat treatment or the like as necessary (FIG. 4). 2 and 3, the surface from the thick portion to the thin portion (removed portion) at the tip portion of the substrate 2 is an obtuse inclined surface here, but it is an acute inclined surface. Alternatively, it may be a right-angled surface that gives a stepped shape, or even a rounded surface without any problem.

The width of the portion of the ceramic substrate 2 where the heating resistor is formed (the thickness of the substrate tip portion: for example, the length of the substrate 2 tip portion in the left-right direction in FIG. 2) is required at the head tip portion. It is properly selected according to the printing or printing characteristics, etc., but in the present invention, 10 is selected.
Approximately 400 μm, preferably approximately 20 to 100 μm is suitably adopted. That is, if the width is thinner than 10 μm, the width of the heating resistor becomes short, and a dot shape with good quality cannot be obtained. If it is thicker than 400 μm, the distance between the heating resistor and the heat radiator becomes large, and the heat generation This is because the problem of heat storage in the part occurs, and in order to obtain high quality recording, it is desirable to set the width within the above range.

Specific examples of the 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, a free-cutting glass-ceramic substrate containing mica is preferably used.

That is, since the substrate 2 has the thin end portion as described above, when the heating resistor 8 is used in various recording systems, the heating resistor 8 is used as a film or thermal paper. Since it is efficiently pressed against the substrate, the contact property is significantly improved. On the other hand, in order to efficiently concentrate the generated heat to a necessary portion, the substrate 2
Is necessary to have a moderate heat storage property,
Alumina, aluminum nitride, etc. are not so small in heat storage, not so much heat storage as glass, and free-cutting glass ceramics containing mica are preferably used, and thus good heat generation response can be obtained, and further It is possible to improve the recording quality.

Moreover, as shown in FIGS. 2 and 3, when machining is performed so that only a predetermined portion of the head tip portion becomes thin, the free-cutting glass-ceramic substrate containing mica described above has machinability. Therefore, it is possible to easily form a highly accurate thin-walled tip portion.

Further, as described above, the substrate 2 and the heating resistor are conventionally used by using the free-cutting glass ceramic substrate which is suitable for heat storage as the substrate 2 and which can easily obtain a highly accurate substrate surface by machining. It is no longer necessary to provide a glaze layer that was inevitably provided between the heat generating element and the glaze layer, and the problem of shortening the life of the heating element due to the reaction between the heating element and the glaze layer can be avoided. The advantage of being done is also demonstrated.

By the way, in the thermal head having such a structure, the predetermined heat radiating body 12 is provided so as to be located at least at the tip of the substrate 2 and close to the heat generating resistor. By disposing the heat dissipating body 12 close to the heat dissipating resistor 8, the heat dissipating characteristic of the heat dissipating resistor 12 is improved, and thus good recording quality without dot blurring or tailing can be obtained.

More specifically, as the material for forming the heat radiator 12, more specifically, free-cutting alumina, free-cutting boron nitride, free-cutting aluminum nitride, shinchu, copper,
A material containing a material selected from aluminum, bronze, etc. as a main component or a material obtained by combining them is preferably adopted. Among them, free-cutting alumina, free-cutting boron nitride, free-cutting aluminum nitride, etc. are main components. The material to be
It is preferably used because it has excellent slidability and contactability of the head. In addition, the heat dissipating body 12 provided in the vicinity of the heat generating resistor 8 is provided on the contact surface of the head with the heat sensitive paper or film so as to directly contact with the heat sensitive paper or film in order to improve heat dissipation. 8 is preferably installed on the same plane.

Further, in the thermal head having such a structure, as shown in FIG. 5, it is advantageous that the main part of the substrate 2 is provided at least with respect to the thin-walled 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 attached via an adhesive 10 so as to reinforce at least the thin-walled portion of the head tip end portion along the shape of the substrate of the head tip end portion. The reinforcing material 14 is preferably provided with a material having a hardness lower than that of the recording electrode 4 or the return electrode 6 and more easily abraded 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. The material is appropriately selected and used. As a result, the heating resistor 8 provided on the end surface of the substrate 2 slides on the thermal paper or film,
It becomes a shape that protrudes slightly forward from the end surface of the reinforcing material 14,
Both mechanical strength and contact property can be satisfied.

More specifically, examples of the wear-resistant material constituting the reinforcing material 14 include free-cutting glass ceramic, free-cutting glass ceramic containing mica, free-cutting alumina, free-cutting boron nitride, and free-cutting boron nitride. Machinable aluminum nitride, a material containing as a main component a material selected from brass, copper, aluminum, bronze, or the like, or a combination thereof is preferably adopted. Among them, a free-cutting glass ceramic containing mica, Machinable alumina, free-machining boron nitride,
A material containing free-cutting aluminum nitride as a main component is preferably used because it is excellent in slidability and contact of the head. In particular, a material containing free-cutting alumina, free-cutting boron nitride, free-cutting aluminum nitride, etc. as the main component has excellent thermal conductivity, and therefore has the role of the above-mentioned heat radiator 12. By providing the reinforcing material made of such a wear-resistant material, the heat radiation characteristics can be further improved.

As described above, in the thermal head structure as described above, the predetermined reinforcing material 14 is provided at least at the tip of the head, so that the thermal paper, the film, or the like can be used during its use. Peeling of the heating resistor 8 or the protective layer (24) due to sliding contact is not caused, and the peeled matter or the like is sandwiched between the electrode and the thermal paper or the like, which causes a problem of impeding printing or printing. Excellent characteristics are exhibited in that it does not occur.

The radiator 12 and the reinforcing member 14 as described above are used.
As the adhesive material 10 for sticking the
An inorganic material containing silica, boron nitride, or the like, or a resin material containing epoxy, phenol, polyimide, or the like, or a composite material containing these inorganic material and resin material may be used. Of these, inorganic materials including alumina, silica, boron nitride, etc. are preferably selected.

Further, in the present invention, in order to protect the heating resistor 8, the electrodes 4, 6, etc., an appropriate insulating material such as silicon oxide, silicon nitride, silicon carbide, or Using a material appropriately selected from tantalum oxide, glass, etc., the protective layer 24 is provided at least on the tip of the head.
It is also possible to provide (see FIGS. 13 to 15), and the protective layer 24 can effectively prevent oxidation, wear resistance, and insulation coating. The protective layer 24
Is provided according to a known method such as sputtering, CVD, or a thick film method, and may have not only a single layer structure selected from the above materials but also a multilayer structure formed from the above materials, and will be described later. When used for the insulation coating of the lead, an organic material such as epoxy, phenol, polyimide or the like is advantageously used.

Further, in the thermal head according to the present invention, as shown in FIG. 6, an electrical insulating layer such as glass, a so-called glaze layer 16 is formed on the main plane and the tip surface of the substrate 2, if necessary. It is also possible to have a structure in which the recording electrode 4 and the return electrode 6 are supported thereon. As a result, the heat diffusion in the heating resistor 8 is delayed and the resistor 8 can be more firmly bonded to the substrate 2.

The recording electrode 4 and the return electrode 6 respectively provided on the substrate 2 are made of a usual conductor material, but especially chromium, titanium, molybdenum, tungsten,
It is appropriately selected and used from metals such as nickel, gold and copper, alloys containing them, nitrides, carbides and borides of these metals. Further, the recording electrode 4 and the return electrode 6 are formed on the respective main planes of the substrate 2 by the usual thin film method, thick film method, etc., using the electrode material as described above. The recording electrode 4 is usually patterned according to the recording density of the head, while the return electrode 6 may be patterned similarly to the recording electrode 4, but is preferably provided as a common electrode. And is formed into a layer by a known appropriate method or 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, more preferably 3 μm or more. Can also be
It is possible.

On the other hand, the heating resistor 8 provided in 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. Material containing high melting point metal or its alloy as the main component, material containing high melting point metal or its alloy with any of oxides, nitrides, borides and carbides, or titanium, tantalum, chromium, zirconium , Materials containing at least one element selected from hafnium, vanadium, lanthanum, molybdenum, tungsten, etc. as a main component, carbide, boride, silicide, etc., materials containing ruthenium oxide as a main component, etc. It will be adopted appropriately. Then, such a heating resistor 8 is formed into a pattern according to the recording density of the head by a normal thin film method or the like, or is provided in a continuous single strip shape.

By the way, as shown in FIGS. 1 to 6, the substrate surface of the thin portion located at least at the tip of the substrate 2 forming the above-mentioned heating resistor 8 does not necessarily support the electrodes 4, 6 (so-called). The surface does not need to be a plane (so-called end surface) orthogonal to the main plane, and as shown in FIGS. 7 and 8, it may be an oblique plane with respect to the main plane or a curved surface continuously curved from the main plane. Good. Furthermore, as shown in FIG. 9, even if the end portion 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, Any of them can be appropriately adopted without any problem.

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

In FIG. 11, the recording electrode 4 is supported on one main plane of the substrate 2 via the glaze layer 16, and the other main plane is supported by the common electrode (return electrode) via the adhesive 10. ) Is an example of a thermal head having a structure in which an electrode plate 20 having a predetermined thickness is bonded to each other.
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 heating resistor 8 is provided on the tip of the substrate 2 and then the recording electrode 4 and the return electrode 6 are formed on the main planes facing each other. It should be noted that on the recording electrode 4 and the return electrode 6, the same reinforcing member 14 and radiator 12 as in the case of FIG. 10 are joined and integrally provided.

13 to 15, respectively,
An example in which a suitable protective layer 24 is further provided on the heating resistor 8 is shown. That is, in FIG. 13, the electrodes 4 and 6 are provided on both main planes of the substrate 2 via the glaze layers 16, respectively, and further on the outside thereof, the reinforcing material 1 via the adhesive 10.
4. This is an example in which the radiator 12 is provided, and after the heating resistor 8 is formed on the head end surface, the protective layer 24 having a predetermined thickness is provided so as to cover the head end surface. FIG.
After the electrodes 4 and 6 are formed on the substrate 2, the heating resistor 8 and the protective layer 24 are sequentially formed, and then the radiator 12 and
FIG. 15 shows an example in which the reinforcing member 14 is provided, and 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 tip end surface thereof. , The reinforcing material 14 and the radiator 1 on the outer sides of both main planes of the substrate 2, respectively.
This is an example in which 2 is provided.

The specific construction and embodiments of the present invention have been described above 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 thereto. It is to be understood that various changes, modifications, improvements and the like can be made to the present invention without departing from the knowledge of those skilled in the art.

[0033]

As is apparent from the above description, in the end surface type thermal head according to the present invention, at least the tip portion of the ceramic substrate is thin, and the heating resistor is provided in the thin portion. Since the recording electrode and the return electrode for energizing the heating resistor are supported by the substrate, the contact between the heating resistor and the thermal paper or film is good, and the heat responsiveness is also excellent. It is possible to advantageously improve the printing quality, and since 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 released heat is quickly dissipated, so that good quality without dot blurring or tailing can be obtained in high-speed printing or printing.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional explanatory view showing another example of the end surface type thermal head according to the present invention.

FIG. 3 is a sectional explanatory view showing still another example of the end surface type thermal head according to the present invention.

FIG. 4 shows an end surface type thermal head according to the present invention,
It is a cross-sectional explanatory view showing an example in which the substrate has a laminated structure.

FIG. 5 shows an end surface type thermal head according to the present invention,
FIG. 6 is a cross-sectional explanatory view showing an example in which a reinforcing material is provided on one surface of the main plane of the substrate.

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

FIG. 7 shows an end surface type thermal head according to the present invention,
It is sectional explanatory drawing which shows an example in which the board | substrate surface located in a front-end | tip part is not a surface orthogonal to a main plane.

FIG. 8 shows an end surface type thermal head according to the present invention,
It is sectional explanatory drawing which shows another example in which the board | substrate surface located in a front-end | tip part is not a surface orthogonal to a main plane.

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

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

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

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

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

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

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

[Explanation of symbols]

 2 Substrate 4 Recording Electrode 6 Return Electrode 8 Heating Resistor 10 Adhesive 12 Heat Dissipator 14 Reinforcing Material 16 Glaze Layer 20 Electrode Plate 22 Insulating Material 24 Protective Layer 26 Lead

Claims (1)

Claim: What is claimed is: 1. A ceramic substrate is thinned at least at its tip, and a heating resistor is provided on the thinned portion.
A recording electrode and a return electrode for energizing the heating resistor are respectively supported by the ceramic substrate, and are located at least at the tip of the ceramic substrate,
An end surface type thermal head is characterized in that a heat radiator is provided so as to be close to the heat generating resistor. 2. The end surface type thermal head according to claim 1, wherein the substrate is a free-cutting glass ceramic substrate containing mica. 3. The end surface type thermal head according to claim 1, wherein the heating resistor is directly formed on the substrate.