JPH0577461A - Thermal head - Google Patents

Abstract

PURPOSE:To simply bond both members and to prevent the release of the bonded part by integrally sintering a plurality of members composed of green sheets and forming a heating resistor to the surface of one member and forming an electrode to the surface of the other member from both side parts of the heating resistor. CONSTITUTION:The thermal head 27 of a thermal printer is constituted by unifying a first member 30 composed of a green sheet having a flat upper surface 28 and a flat rear surface 29 with the flat surface 32 of a second member 31 composed of a separate green sheet to sinter both members. At this time, an inclined surface 33 composed of a flat surface is formed to one edge part of the first member 30 in a sub-scanning direction and a glass glaze layer 34, a Ta-SiO2 layer 35 and an Al layer 36 are respectively arranged to the upper surface 28. The Al layer 36 is divided on the upper surface 28 to respectively form an individual electrode 37 and a common electrode 38. A heating resistor 39 is formed by the Ta-SiO2 layer 35 positioned between both electrodes 37, 38. By this constitution, both members 30, 31 are simply bonded and the release of the bonded part, is prevented.

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 for printing on a prepaid card or the like.

[0002]

2. Description of the Related Art At present, various types of printers have been put to practical use, for example, a thermal printer for printing on a prepaid card and the like. Therefore, as a first conventional example of such a thermal printer, Japanese Patent Laid-Open No.
The device disclosed in Japanese Patent No. 113262 will be described with reference to FIGS. First, in this thermal printer 1, as shown in FIG.
As illustrated in FIG. 2, a heating resistor 6 in which an individual electrode 4 and a common electrode 5 are integrally formed at both ends is formed on the glass glaze layer 3 formed on the surface of the ceramic substrate 2 by photolithography or the like. The ceramic substrate 2 is attached to the end face of a rectangular parallelepiped radiator plate 7. A driver IC (Integrated Circuit) 8 which is a drive circuit is mounted on the front surface of the heat dissipation plate 7, and the driver IC 8 is a bonding lead 9 which is a wiring material.
Then, the TAB (Tape
Autometed Bonding). The thermal head 11 is formed by attaching the protective cover 10 covering the driver IC 8, the bonding leads 9, the individual electrodes 4, etc. to the heat dissipation plate 7.

In this thermal printer 1, as shown in FIG. 6, a platen roller 12 is pivotally supported at a position facing the heating resistor 6 exposed from the end surface of the protective cover 10 of the thermal head 11. A conveyance path for the ink ribbon 13 and the recording medium 14 is formed between the platen roller 12 and the ceramic substrate 2.

In such a structure, in the thermal printer 1, the heating resistor 6 is generated by selectively switching the driver IC 8 in accordance with the input print data.
The driving power is applied to the recording medium 14, and the recording medium 14 is conveyed by the rotation of the platen roller 12 in synchronization with the heating scanning of the heating resistor 6, so that the ink ribbon 1 is recorded on the recording medium 14.
Image printing is performed by fusing the ink of No. 3.

Here, in the above-described thermal printer 1, by covering the connecting portion between the individual electrode 4 and the bonding lead 9 with the protective cover 10, it is possible to prevent the ink ribbon 13 and the recording medium 14 from coming into contact therewith. ing. But,
Since such a protective cover 10 projects more than the heating resistor 6, the recording medium 14 pressed by the platen roller 12 against the heating resistor 6 is bent at a step with the protective cover 10 as illustrated in FIG. Will be done. That is, in this thermal printer 1, it is difficult to use a non-curvable prepaid card or the like as the recording medium 14.

Further, as a thermal printer which solves such a problem, there are Japanese Patent Laid-Open Nos. 60-21263 and 59.
There is a device disclosed in Japanese Patent Publication No. 79774. First, Japanese Patent Laid-Open No. 60
The thermal printer disclosed in Japanese Patent Publication No. -21263 will be described as a second conventional example with reference to FIG. In the thermal head 15 of this thermal printer (not shown), a cylindrical glass glaze layer 17 is formed on an end surface of a ceramic substrate 16, and a flat surface portion having a width of 1.0 to 2.5 (mm) is located at the apex. The heating resistor 6 is formed on the top. The other structure is the same as that of the thermal printer 1 described above.

With this structure, in the thermal head 15, even if the platen roller 12 is disposed so as to face the heating resistor 6 with the protective cover 10 attached so as to cover the individual electrode 4, the heating resistor 6 is also provided. Can be projected beyond the surface of the protective cover 10. Therefore, in the thermal head 15, it is possible to prevent the recording medium 14 from being bent by the platen roller 12 and pressed against the heating resistor 6, so that a non-curvable prepaid card or the like can be used as the recording medium 14. Is.

Further, the thermal printer disclosed in Japanese Patent Laid-Open No. 59-79774 will be described as a third conventional example with reference to FIG. Thermal head 1 of this thermal printer
In FIG. 8, four trapezoidal head substrates 20 are continuously mounted on one support 19 in the sub-scanning direction, and a heating resistor is placed on the plane formed at the apex of these head substrates 20. 21 are continuously formed in the main scanning direction. A common electrode 22 and an individual electrode 23 are integrally formed on both edges of the heating resistor 21 in the sub-scanning direction, and the individual electrode 23 is extended to the inclined surface of the head substrate 20. The bonding wire 24 is connected to the drive IC 25 composed of a chip component. This drive I
C25 is fixed on the support 19 between the head substrates 20, and the upper portion thereof is lower than the heating resistor 21.

In such a structure, in the thermal head 18, ink ribbons (not shown) of three primary colors and black are set on each of the four head substrates 20 to execute color printing. .. Here, in this thermal head 18, it is disclosed that the drive IC 25 and the bonding wire 24 are protected by being sealed with a resin material (not shown) or the like, but even in this case, the heating resistor 21 is projected. Printing can be performed without bending a recording medium (not shown).

[0010]

In the thermal head 15 illustrated as the second conventional example, the heating resistor 6 formed on the apex of the cylindrical glass glaze layer 17 is projected from the surface of the protective cover 10. By doing so, an image can be printed on the recording medium 14 such as a prepaid card that cannot be curved.

However, in the thermal head 15, as described above, it is necessary to form the heating resistor 6 and the electrodes 4 and 5 on the curved surface of the glass glaze layer 17 protruding cylindrically by photolithography or vapor deposition. However, its productivity is low and it is difficult to improve the yield.

Further, in the thermal head 18 illustrated as the third conventional example, the heating resistor 21 formed on the top plane of the trapezoidal head substrate 20 is provided more than the drive IC 25 and the bonding wire 24 located on the support table 19. By projecting the image, it is possible to print an image on a recording medium that cannot be curved.

However, in the thermal head 18, the individual electrodes 23 located on the inclined surface of the trapezoidal head substrate 20.
Although it is illustrated that the bonding wire 24 is connected, the yield of the device will be significantly reduced even if this is performed. Furthermore, with this thermal head 18,
A head substrate 20 made of ceramic is mounted on a metal support 1
It is disclosed to be mounted on the substrate 9, and joining between such materials generally needs to be performed by adhesion or the like. However, such adhesion increases the manufacturing process of the thermal head 18 and hinders the productivity, and moreover, the adhesive strength of the adhesive is likely to decrease due to aging, temperature change and the like. Further, the thermal head 18 inevitably repeats heat generation and cooling, but in the above-mentioned materials, since the thermal expansion coefficient of the support base 19 and the head substrate 20 are different, peeling is likely to occur at the joint portion.

The present invention is to obtain a thermal head having good productivity and durability.

[0015]

[Means for Solving the Problems] A green sheet is used in which a first member is formed of a green sheet having at least a front surface and a back surface formed into a flat surface, and the first member is disposed on the flat surface and integrally sintered. A second member is formed of a sheet, and a heating resistor is continuously provided in the main scanning direction on the surface of the first member,
Electrodes were formed from both sides of these heating resistors in the sub-scanning direction to the surface of the second member.

[0016]

[Function] Since the first member and the second member made of the green sheet can be easily joined by sintering, and the material properties such as the coefficient of thermal expansion are the same, the joining portion due to aging, temperature change, etc. It is possible to obtain a thermal head in which peeling is prevented and which has good productivity and durability.

[0017]

Embodiments of the present invention will be described with reference to FIGS. First, as illustrated in FIG. 1, the thermal head 27 of the thermal printer 26 includes a first member 30 made of a green sheet having a front surface 28 and a back surface 29 formed of a flat surface, and a second member 31 made of a green sheet. It has a structure in which it is integrally joined to the surface 32 formed of the plane. Here, the first member 30 has a substantially trapezoidal shape with a flat inclined surface 33 formed at one edge in the sub-scanning direction, and has a glass glaze layer 34 and Ta− on the surface 28.
The SiO ₂ layer 35 and the Al layer 36 are provided by sputtering or the like. Here, the Ta-SiO ₂ layer 35 and the Al layer 3
6 is extended to the surface 32 of the second member 31 via the inclined surface 33, and the Al layer 36 is divided on the surface 28 to form an individual electrode 37 and a common electrode 38. ing. A heating resistor 39 is formed of the Ta—SiO ₂ layer 35 located between the electrodes 37 and 38, and a protective film 40 is formed on the heating resistor 39. It should be noted that, as illustrated in FIG.
The a-SiO ₂ layer 35 and the Al layer 36 are patterned into a predetermined shape, and the electrode 3 exposed on the surface 32 of the second member 31 without being covered with the protective film 40.
The ends of 7, 38 are terminal portions 41, 42.

In the thermal printer 26, as shown in FIG. 2, the thermal head 27 having the above-described structure is mounted on the end surface of the heat dissipation plate 43 made of aluminum or the like, and the side surface of the heat dissipation plate 43 is provided. The drive IC 45 is mounted on the circuit board 44 mounted on the. Here, this drive I
C45 is a printed wiring formed on the circuit board 44.
A terminal portion 4 which is connected to a bonding wire 46 (not shown) and comprises a printed wiring of the circuit board 44.
7 and the terminal portions 41 and 42 of the thermal head 27,
FPC thermocompression bonded with anisotropic conductive film (not shown)
(Flexible Printed Circuit Board) 48 is connected. In the thermal printer 26, the FPC 48, the thermal head 27 and the circuit board 4 are
4 is sealed with a resin material (not shown) or the like, and the heating resistor 39 of the thermal head 27 is sealed.
A recording medium 49 such as a prepaid card at a position facing
The platen roller 50 is axially supported via the conveyance path of.

With this structure, in the thermal printer 26, the heating resistor 39 formed on the surface 28 of the first member 30 projects from the FPC 48 or resin material connected to the surface of the second member 31. Therefore, image printing can be performed without bending the recording medium 49.

In addition, in the thermal head 27 of the thermal printer 26, the first and second members 30 and 31 forming the above-mentioned shape are formed of green sheets and are integrally sintered. Good joint strength and productivity.

A specific example of the method of manufacturing the thermal head 27 will be described below. First, a raw material powder is mixed with an organic binder, a plasticizer and a solvent to form a slurry,
After vacuum defoaming this with a closed stirrer, it is formed into a predetermined thickness by a doctor blade method, a roll coater method, or the like to form a green sheet that is a material for the first and second members 30 and 31. For example, in the doctor blade method, a doctor blade is installed on a running plastic film and the slurry is poured therein. Then, this slurry is formed into a predetermined thickness when it passes under the doctor blade, and thus it is dried to obtain a green sheet.

Since the green sheet thus produced can be easily cut, etc., it is formed into the shapes of the first and second members 30 and 31 and then laminated and thermocompressed. By sintering, the first and second members 30, 31 that are firmly integrated can be obtained.

Further, after the joining of the first and second members 30 and 31 is completed as described above, as shown in FIG. 3A, the surface 28 of the first member 30 is formed by the existing thin film technique. By forming a glass glaze layer 34 and forming a Ta—SiO ₂ layer 35 and an Al layer 36 thereon by a sputtering method and patterning by a photolithography method, as illustrated in FIG. The thermal head 27 can be obtained.

By doing so, the first and second members 3
Since the green sheet, which is the material of 0 and 31, can be formed by cutting or the like very easily, it can contribute to the improvement of the productivity of the thermal head 27. Furthermore, these first and second members 30 and 31 can be easily joined by sintering without the need for an adhesive or the like, and since the material properties such as the coefficient of thermal expansion are the same, secular change and temperature change. Peeling of the joint due to changes or the like is prevented.
Therefore, the thermal head 27 is excellent in both productivity and durability.

In the thermal head 27 of this embodiment, the electrodes 37 extending from the heating resistor 39 to the surface 32 of the second member 31 via the inclined surface 33 formed on the first member 30,
However, the present invention is not limited to the above structure, and as shown in FIG. 4, the electrodes 37 and 38 are formed in the first member 51 via the via hole 52. The thermal head 53 and the like formed as described above can also be implemented. In this case, in the thermal head 53, the conductive paste 54 is press-fitted into the via hole 52 formed in the first member 51 and the second member 31 is joined before the first and second members 51 and 31 are joined by thermocompression bonding or the like. The conductive paste 54 is printed on the surface 32 of the above, and a part of the electrode is formed by these conductive pastes 54.

[0026]

As described above, according to the present invention, the first member is formed of the green sheet having at least the front surface and the back surface which are flat, and the first member is arranged on the flat surface and integrally baked. The second member is formed of the green sheets to be joined, and the heating resistors are continuously provided on the surface of the first member in the main scanning direction, and the second member is formed from both sides of these heating resistors in the sub scanning direction. By forming the electrodes that reach the surface of
The first and second members made of green sheets can be easily joined by sintering and the material properties such as coefficient of thermal expansion are the same, so peeling of the joint due to aging or temperature change is prevented. In addition, the thermal head having good productivity and durability can be obtained.

[Brief description of drawings]

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

FIG. 2 is a side view showing a thermal printer.

FIG. 3 is a perspective view showing a manufacturing process.

FIG. 4 is a vertical sectional side view showing a modified example.

FIG. 5 is a perspective view showing a first conventional example.

FIG. 6 is a vertical sectional side view.

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

FIG. 8 is a perspective view showing a third conventional example.

[Explanation of symbols]

 27,53 Thermal head 28 Front surface 29 Back surface 30,51 First member 31 Second member 32 Surface 37,38,54 Electrode 39 Heating resistor

Claims (1)

[Claims] 1. A first member is formed of a green sheet having at least a front surface and a back surface formed into a flat surface, and the first member is arranged on a flat surface and sintered integrally. A member is formed, heating resistors are continuously provided on the surface of the first member in the main scanning direction, and electrodes extending from both sides of these heating resistors in the sub scanning direction to the surface of the second member are formed. A thermal head that is characterized.