JPH05527A - End face-type thermal head - Google Patents

Abstract

PURPOSE:To obtain an end face-type thermal head with a superior heat generation response, a high recording sensitivity, and a good recording quality even in a high-speed printing. CONSTITUTION:In a thermal head in which at least a top end part of a ceramic substrate 20 is made a thin wall; a heating resistor 26 is provided on the thin wall part; and recording electrodes 22 and return electrodes 24 for passing an electric current to the heating resistor 26 are respectively supported on the ceramic substrate 20, a heat release body 28 is disposed on at least the top end part of the ceramic substrate 20 in proximity to the heating resistor 26. The ceramic substrate 20 is made of a material having a thermal conductivity ranging from 0.002 to 0.03cal.cm/sec.cm<2>. deg.C, which is lower than that of the heat release body 28.

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 surface type thermal head, it is difficult to perform high-precision processing on the end surface of the substrate on which a predetermined heating resistor is formed, and the thermal characteristics of the heating resistor are improved to perform patterning. In order to reduce wiring failure at the time, as shown in FIG.
Although the glaze layer 6 is formed on the surface on which the heating resistor 4 is formed, it is difficult to uniformly form the glaze layer 6 on such an end face, and the thermal characteristics due to the formation of the glaze layer 6 In the adjustment, there are many restrictions on the substrate shape and the glaze shape, and there are inherent problems such as a low degree of freedom in thermal design. Furthermore, in such a conventional end surface type thermal head, since the heat generating resistance portion (4) is projected from the base 8 supporting the entire head toward the thermal paper or film, It is often difficult to quickly dissipate heat to the base 8 etc. after using the heat generated in the heat-generating resistor section (4) for printing, and therefore dot blurring, tailing, etc. occur and recording quality is sufficiently good. It wasn't something. In FIG. 1, 10 is a recording electrode, 12 is a return electrode, and 14 is a protective layer.

[0005]

The present invention has been completed in view of the above-mentioned circumstances, and the problems to be solved are excellent heat generation response, high recording sensitivity, and high-speed printing. Another object of the present invention is to provide an end surface type thermal head having a good recording quality even during copying.

[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. A recording electrode and a return electrode for carrying out, respectively, in an end face type thermal head supported by the ceramic substrate, so as to be located at least at the tip of the ceramic substrate and close to the heating resistor, While providing a radiator, the ceramic substrate has a lower thermal conductivity than the radiator, and the value of the thermal conductivity is 0.002 cal · cm / sec · cm ² · ° C.
The gist of the present invention is the end face type thermal head, which is characterized in that it is made of a material of 0.03 cal · cm / sec · cm ² · ° C or less.

In the end face type thermal head according to the present invention, the radiator preferably has a higher thermal conductivity than the ceramic substrate, and the value of the thermal conductivity is 0.01. It will be composed of materials with cal · cm / sec · cm ² · ° C or higher.

Further, according to the present invention, at least the tip portion of the ceramic substrate is made thin, a heating resistor is provided on the thin portion, and a recording electrode and a return electrode for energizing the heating resistor are respectively provided. In the end face type thermal head supported by the ceramic substrate, 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.
The heat radiator has a higher thermal conductivity than that of the ceramic substrate, and the value of the thermal conductivity is 0.01 cal · cm / sec.
An end face type thermal head characterized by being made of a material having a cm ² · ° C. or higher is also the gist thereof.

By the way, in the thermal transfer recording, in order to effectively utilize the heat generated in the heating resistor at the head end portion for transfer, it is necessary to accurately control the thermal characteristic of the head end portion, that is, the heat storage property. However,
In a conventional thermal head, when a material such as alumina or metal having a relatively high thermal conductivity is used as the substrate, the heat storage property is low, and therefore the heat generated by the heating resistor is sufficiently used for transfer. It was diffused without getting it. Further, as seen in the example of the conventional thermal head shown in the figure, in the structure in which the glass glaze layer 6 is formed on the substrate 2 to secure the heat storage property, the cost becomes high and the material of the glaze layer is made. There are many restrictions on the shape and forming method,
Free heat design was difficult. Furthermore, in an example of a conventional thermal head, there is one in which a cylindrical glass rod is used as a substrate of an end portion, but in such a thermal head, since the heat storage property of glass is too high, The print quality was degraded.

Therefore, the substrate supporting the heating resistor has a lower thermal conductivity than that of a material such as alumina or metal having a relatively high thermal conductivity, and a higher value than a glass having a relatively low thermal conductivity. By forming the material, the above problems can be solved. In addition, by forming a target substrate using a material having such a thermal conductivity, it is not necessary to form a glaze layer, and thus cost can be reduced.

Further, by forming the substrate using the material having the above-mentioned thermal conductivity, the shape of the substrate itself,
That is, the volume can be freely changed to control the heat storage property of the head tip portion, thereby improving the degree of freedom in designing the thermal characteristics.

Furthermore, the tip of the substrate is made thin,
A heat radiator made of a material having a relatively high thermal conductivity is installed in a position close to the heat generating resistor, and the heat conductivity of the heat radiator is regulated to transfer the heat generated in the heat generating resistor. After being effectively used, the heat is quickly diffused to the head base side, so that high-quality printing can be obtained without blurring of printing dots, blurring, tailing, and the like. In particular, such improvement of the heat dissipation characteristic works effectively during high-speed printing.

[0013]

Specific Structure / Examples In order to more specifically clarify the present invention, a specific structure of the present invention will be described in detail with reference to Examples.

First, FIGS. 2 and 3 and FIGS. 4 and 5 respectively show different examples of the end surface type thermal head according to the present invention. In those figures, the ceramic substrate 2
0 is formed by using a predetermined material so that at least its tip portion is thin, and one main plane thereof is provided with a large number of stripe-shaped recording electrodes 22 and the other main electrode is provided. A sheet-like return electrode 24 is provided on the plane corresponding to the surface shape, and these electrodes 22, 2
4 are respectively supported on the ceramic substrate 20. A heating resistor 26 is provided on the end surface of the thin tip portion of the ceramic substrate 20 so as to be electrically connected to the recording electrode 22 and the return electrode 24. Furthermore,
A radiator 28 is provided outside the main plane supporting the return electrode 24 of the ceramic substrate 20 so as to be located at least at the head tip and close to the heating resistor 26.
They are bonded to each other through the slits 0 to form an integral head structure.

In particular, in the head tip portion structure shown in FIGS. 2 and 3, the tip portion is thinned by the inclined surface extending gradually from one main plane of the ceramic substrate 20 to the other main plane. The radiator 28 is provided so as to be located at least on the inclined surface, and the tip end surface is inclined so as to form an acute angle with the extension surface of the other main plane, and the inclined tip end The heating resistor 26 is provided on the surface. Then, a protective layer 32 having a predetermined thickness is provided so as to cover the head end surface on which the heating resistor 26 is provided.

In the end surface type thermal head shown in FIGS. 4 and 5, one main plane and the front end surface of the ceramic substrate 20 having a thin front end portion having a predetermined thickness and extending in front of the inclined surface similar to the previous example. The glaze layer 34 is provided,
The recording electrode 22 is provided on the one main plane, and the return electrode 24 is provided on the other opposite main plane. Furthermore, the ceramic substrate 20 is electrically connected to the recording electrode 22 and the return electrode 24.
A heat generating resistor 26 is formed on the end face of the head, a heat radiator 28 is provided outside the return electrode 24 at the head tip, and a mechanical strength of the head tip is provided outside the recording electrode 22. Reinforcement bodies 36 are attached to each other via the adhesive material 30. Also in this example, the protective layer 32 having a predetermined thickness is provided so as to cover the head end surface.

In such an end face type thermal head, the ceramic substrate 20 needs to be constructed so that at least the head tip portion thereof is thin as shown in the drawing. As shown in FIGS. 4A and 4B, even if the tip surface is the thinnest, as shown in FIGS. 4 and 5, the thinnest portion of the substrate extends over a predetermined distance from the tip to the substrate base side. Even if the shape is continuous, it does not matter at all. However,
In the thinned structure as shown in 3, the mechanical strength at the tip of the head can be sufficiently ensured, and the pressing of the head against the film or the thermal paper can be sufficiently increased. Further, in the thinned structure as shown in FIGS. 4 and 5, the surface from the thick portion to the thin portion at the tip end portion of the substrate 20 is an obtuse angled inclined surface, which also has a stepped shape. The surface may be a right-angled surface, or may be a rounded surface without any problem.

The width of the portion of the ceramic substrate 20 where the heating resistor 26 is formed (thickness of the front end of the substrate):
Although d is appropriately selected according to the printing or printing characteristics required for the head end portion, in the present invention, it is about 10 to 400 μm, preferably 20 to 10 μm.
About 0 μm is preferably adopted. That is, the width is 10
If the width is smaller than μm, the width of the heating resistor 26 becomes narrow, and a dot shape of good quality cannot be obtained. If the thickness is larger than 400 μm, a problem of heat storage in the heating resistor part occurs, so that high quality recording is performed. In order to obtain it, it is desirable to set the width within the above range.

By the way, the ceramic substrate 20 in the thermal head having such a structure has a thermal conductivity lower than that of the radiator 28 and is 0.002 cal.
・ Cm / sec ・ cm ²・ ℃ or more, 0.03 cal ・ cm / sec ・
cm ² · ° C or less, preferably 0.002 cal · cm / sec
.Cm ² · ° C. or more and 0.01 cal · cm / sec · cm ² · ° C. or less, and more preferably has such a thermal conductivity value while having a unit volume per unit volume. It is made of a material having a heat capacity of 0.55 cal / ° C · cm ³ or less. That is, by adopting a material having such a thermophysical property value, it is possible to advantageously realize the control of the thermal characteristics of the head tip portion. Specific examples of the substrate 20 having such characteristics include a glass ceramic substrate, a free-cutting glass ceramic substrate, and a free-cutting glass ceramic substrate containing mica. It is selected in consideration of the thermal conductivity of the body 28, but among them, a free-cutting glass ceramic substrate containing mica is advantageously used.

That is, since the ceramic substrate 20 has the thin end portion as described above, when the ceramic substrate 20 is used for various recording methods via the heating resistor 26, the heating resistor 26 is used as a film or a film. Although it is efficiently pressed against the thermal paper, its contact property is remarkably improved. On the other hand, in order to efficiently concentrate the generated heat to a necessary portion, the ceramic substrate 20 should have an appropriate heat storage property. Since it is necessary, the heat storage property is not so low as that of alumina or aluminum nitride having a relatively high heat conductivity, the heat storage property is not so large as that of a glass having a relatively low heat conductivity, and the heat generated by the heating resistor 26 is not so large. Is effectively used for printing, the temperature of the ceramic substrate 20 rises quickly, that is, the heat capacity per unit volume is smaller than that of alumina or metal. Machinable glass ceramic containing squid is than preferably used, good exothermic response is obtained Te following is the more may achieved also improved recording quality. Moreover, as shown in FIGS. 2 to 5, when machining is performed so that a predetermined portion of the head tip end portion is thinned,
The free-cutting glass-ceramic substrate containing such mica has excellent machinability, and therefore can easily form a highly accurate tip thin-walled portion.

Further, as described above, as the ceramic substrate 20, by using a free-cutting glass ceramic substrate suitable for heat storage and capable of easily obtaining a highly accurate substrate surface by machining, the conventional substrate 20 Heating resistor 2
It is not necessary to provide the glaze layer which is inevitably provided between the device 6 and 6, and the cost can be advantageously reduced.
Further, it also has an advantage that the problem of shortening the life of the heating resistor 26 due to the reaction between the heating resistor 26 and the glaze layer can be avoided.

Further, in the thermal head having such a structure, a predetermined radiator 28 is provided so as to be located at least at the tip of the ceramic substrate 20 and close to the heating resistor 26. The radiator 28 is advantageously made of a material having a thermal conductivity higher than that of the ceramic substrate 20 and not lower than 0.01 cal · cm / sec · cm ² · ° C. As described above, by disposing the heat dissipating body 28 having a specific thermal conductivity in close proximity to the heat generating resistor 26, the heat dissipating characteristics of the heat generating resistor 26 are improved, and therefore, dot blurring, tailing, etc. are eliminated. Recording quality can be obtained. Further, the radiator 28 having the specific thermal conductivity exhibits a particularly excellent effect by being used together with the ceramic substrate 20 having the specific thermal conductivity described above, but it is related to the characteristics of the ceramic substrate 20. Instead, the effect of the present invention can be fully enjoyed only by considering the thermal conductivity of the radiator 28.

More specifically, examples of the material forming the heat radiator 28 include free-cutting alumina, free-cutting boron nitride, free-cutting aluminum nitride, brass, copper, aluminum and bronze. It is preferably selected and adopted from materials containing selected materials as main components or materials combining them. Among them, free-cutting alumina, free-cutting boron nitride, free-cutting aluminum nitride, etc. are main constituents. The material described below is preferably used because it is excellent in slidability and contactability of the head. Further, it is desirable that the heat radiator 28 provided in the vicinity of the heat generating resistor 26 be installed so as to directly slide on the thermal paper or film in order to improve the heat radiation property.

Further, in the thermal head having such a structure, as shown in FIGS. 4 and 5, it is advantageous that the ceramic substrate 20 is provided at least with respect to the thin portion at the tip of the head where the heating resistor 26 is provided. In order to reinforce at least the thin-walled portion of the head tip portion on one side of the main plane of the above, a predetermined reinforcing material 36 is attached via an adhesive material 30 along the shape of the substrate of the head tip portion. .. The reinforcing material 36 is preferably the recording electrode 2
2 and the return electrode 24 have a hardness smaller than that of the return electrode 24 and the heating resistor 2
6 is more easily abraded, or when the protective layer 32 is provided, a more easily abraded material is used, but especially the Knoop hardness is 1000 kgf / mm ²
Hereafter, more preferably, a material such as metal, ceramic, glass, glass ceramic or the like having a weight of 500 kgf / mm ² or less is appropriately selected and used. As a result, the heating resistor 26 provided on the end surface of the substrate 20 has a shape that slightly protrudes forward from the end surface of the reinforcing member 36 while sliding on the thermal paper or film, and has both mechanical strength and contactability. You can be satisfied.

More specifically, examples of the wear-resistant material forming the reinforcing member 36 include free-cutting glass ceramics, free-cutting glass ceramics containing mica, free-cutting alumina, and free-cutting boron nitride. , A material mainly containing a material selected from free-cutting aluminum nitride, brass, copper, aluminum, bronze, etc., or a combination thereof is preferably adopted. Among them, a free-cutting glass ceramic containing mica is preferably used. A material containing free-cutting alumina, free-cutting boron nitride, free-cutting aluminum nitride, etc. as the main component is preferably used because it has excellent head slidability and contactability. In particular, free-cutting alumina, free-cutting boron nitride,
Since the material containing free-cutting aluminum nitride as a main component has excellent thermal conductivity, it also serves as the radiator 28 described above. Therefore, the reinforcing material 36 made of such an easily wearable material is provided. Thereby, the heat dissipation characteristics can be further improved.

As described above, in the thermal head structure as described above, the predetermined reinforcing member 36 is arranged at least at the tip of the head, so that the thermal paper structure, the thermal paper, the film or the like can be used. Peeling of the heat generating resistor 26 and the protective layer 32 due to sliding contact is not caused, and the peeled matter or the like may be sandwiched between the electrode and the thermal paper or the like to cause a problem of impeding printing or printing. Excellent features are exhibited in that it does not exist.

The heat radiating body 28 and the reinforcing material 36 as illustrated
To the main surface of the ceramic substrate 20
As 0, even if an inorganic material containing alumina, silica, boron nitride or the like or a resin material containing epoxy, phenol, polyimide or the like is used, a composite containing the inorganic material and the resin material is used. Material may be used,
Among them, inorganic materials including alumina, silica, boron nitride, etc. are preferably selected.

Further, in the present invention, as illustrated,
In order to protect the heating resistor 26 and the electrodes 22 and 24,
If necessary, a suitable insulating material such as silicon oxide,
It is also possible to provide the protective layer 32 at least at the tip of the head by using a material appropriately selected from silicon nitride, silicon carbide, tantalum oxide, glass and the like, and the protective layer 32 prevents oxidation and resistance. Wear, insulation coating, etc. can be effectively achieved. The protective layer 32
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 end surface type thermal head according to the present invention, as shown in FIGS. 4 and 5, an electrical insulating layer such as glass is formed on the main plane and the tip surface of the ceramic substrate 20, if necessary. A so-called glaze layer 34 may be provided and the recording electrode 22 may be supported thereon. In the end face type thermal head according to the present invention, it is not necessary to form the glaze layer on the ceramic substrate 20 from the viewpoint of thermal design, but the glaze layer is required for improving the substrate surface and finely adjusting the thermal design. There is no problem in forming the.

Although ordinary conductor materials are used for the recording electrode 22 and the return electrode 24 provided on the ceramic substrate 20, in particular, metals such as chromium, titanium, molybdenum, tungsten, nickel, gold, copper, and the like are used. It is appropriately selected and used from alloys containing, nitrides of these metals, carbides, borides and the like. In addition, those recording electrodes 22
The return electrode 24 and the return electrode 24 are formed on the respective main planes of the substrate 20 by the ordinary thin film method or thick film method using the electrode material as described above.
Is usually patterned according to the recording density of the head, while the return electrode 24 may be patterned similarly to the recording electrode 22, but is preferably provided as a common electrode. Therefore, they are formed into a layer by a known appropriate method or are joined as a plate-shaped electrode. The thickness of the recording electrode 22 and the return electrode 24 is at least 0.5 μm or more,
The thickness is preferably 1 μm or more, more preferably 3 μm or more, and it is possible to provide a multilayer structure using the above electrode material.

On the other hand, the heating resistor 26 provided in the thin portion at the tip of the ceramic substrate 20 is preferably a thin film resistance film, a thick film resistance film or the like, which has high heat resistance pulse characteristics and high resistance. , A material containing a high melting point metal or an alloy thereof as a main component, a material containing a mixture of a high melting point metal or an alloy thereof and any one of an oxide, a nitride, a boride and a carbide, or titanium, tantalum, chromium, Zirconium, hafnium, vanadium, lanthanum, molybdenum,
A material whose main component is a nitride, carbide, boride, or silicide of at least one element selected from tungsten and the like,
A material containing a ruthenium-based oxide as a main component will be appropriately adopted. Then, such a heating resistor 26
The pattern is formed by a normal thin film method or the like according to the recording density of the head, or is provided in a continuous single strip shape.

In addition, the width of the heating resistor 26 does not have to be the same as the width d of the tip of the ceramic substrate 20, and may be smaller than d or other surface as necessary. It can be formed wide so as to cover the.

Furthermore, as shown in FIGS. 4 and 5, the substrate surface of the thin portion located at least at the tip of the ceramic substrate 20 forming the above-mentioned heating resistor 26 does not necessarily support the electrodes 22 and 24 ( It does not have to be a surface (so-called end surface) orthogonal to the so-called main plane, and as shown in FIGS. 2 and 3, it is an oblique surface with respect to the main plane or a curved surface which is continuously curved from the main plane. May be. Furthermore, even if the end portion connecting the surface mainly supporting the electrodes 22 and 24 and the surface mainly supporting the heating resistor 26 is connected by a curved surface having a radius, it does not matter at all. Can be appropriately adopted.

By the way, the end face type thermal head (sample N) according to the present invention manufactured in the above-exemplified structure is used.
o. 1, 2), and as a comparative example, a ceramic substrate 20.
The head (Sample No. 3,
4) and the thermal conductivity characteristics of the head (Sample No. 5) manufactured according to the configuration of the conventional example are shown in Table 1 below.

[0035]

[Table 1] Table 1 Head configuration sample No. Substrate thermal conductivity * Heat radiator thermal conductivity * Remarks Figure 2, 3 1 0.008 0.04 Invention Figure 4, 5 2 0.004 0.02 Invention Figure 2, 3 3 0.001 0.004 Comparison Example Figure 4, 5 4 0.04 0.04 Comparative Example Figure 1 5 0.002 No Comparative Example * cal · cm / sec · cm ² · ° C

Then, these sample No. As a result of performing an evaluation test for examining printing and image quality with the recording apparatus using the end surface type thermal heads 1 to 5, the sample No. 1 corresponding to the present invention was obtained. In each of the heads 1 and 2, extremely high-definition, high-quality printing with little dot blurring, bleeding, tailing, etc. could be performed at high speed.

On the other hand, sample No. When the heads corresponding to Nos. 3 and 5 are used, dot blurring, bleeding, tailing, etc., which are considered to occur due to heat accumulation in the head,
The print quality was poor and the print quality was unclear. Further, the sample No. When the head corresponding to No. 4 was used, the recording sensitivity was low and the printing was light in density.

Although the specific structure and embodiments of the present invention have been described in detail with reference to the drawings, 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.

[0039]

As is apparent from the above description, according to the present invention, excellent heat generation response, high recording sensitivity, no dot blurring, bleeding, tailing, etc. even at high speed printing, and good printing. A quality recording device can be realized.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing an example of a conventional end surface type thermal head.

FIG. 2 is a perspective view showing an example of an end surface type thermal head according to the present invention.

FIG. 3 is a cross-sectional explanatory diagram of the end surface type thermal head shown in FIG.

FIG. 4 is a perspective view showing another example of the end surface type thermal head according to the present invention.

5 is a cross-sectional explanatory view of the end surface type thermal head shown in FIG.

[Explanation of symbols]

 20 Substrate 22 Recording Electrode 24 Return Electrode 26 Heating Resistor 28 Radiator 30 Adhesive 36 Reinforcement 32 Protective Layer 34 Glaze Layer

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.
In an end face type thermal head in which a recording electrode and a return electrode for energizing the heating resistor are respectively supported by the ceramic substrate, the heating resistor is located at least at the tip of the ceramic substrate. A heat sink is provided so as to be close to the heat sink, while the ceramic substrate has a lower thermal conductivity than the heat sink and the value of the thermal conductivity is 0.002 cal · cm / sec · cm ² ·. An end face type thermal head characterized by being composed of a material having a temperature of ℃ or more and 0.03 cal · cm / sec · cm ² · ° C or less. 2. The ceramic substrate has a thin portion at least at its tip, and a heating resistor is provided on the thin portion,
In an end face type thermal head in which a recording electrode and a return electrode for energizing the heating resistor are respectively supported by the ceramic substrate, the heating resistor is located at least at the tip of the ceramic substrate. While the heat radiator is provided so as to be close to, the heat radiator has a higher thermal conductivity than that of the ceramic substrate, and the value of the thermal conductivity is 0.01 cal · cm / sec · cm ² ·. An end face type thermal head characterized by being made of a material having a temperature of ℃ or higher. 3. The heat radiator has a higher thermal conductivity than the ceramic substrate, and the thermal conductivity value is 0.0.
The end surface type thermal head according to claim 1, which is made of a material having a temperature of 1 cal · cm / sec · cm ² · ° C or higher.