JPH11157109A - Thermal head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute positioning of a head substrate by adequately abutting the edge face of the head substrate to a stopper section by a constitution wherein the stopper section to be brought into contact with an end of the head substrate for positioning the head substrate and a groove section disposed just below the inner side of the stopper section are formed. SOLUTION: This thermal head comprises a head substrate 1 wherein a heating resistor array consisting of a plurality of heating resistors 2a is provided along a side on a rectangular top face and a heat sink plate having the head substrate 1 provided thereon. A stopper section 3a to which the edge face along the side of the head substrate 1 is abutted and a groove section 3b formed just below the head substrate 1 in the vicinity of the stopper section 3a are provided to only portions at both sides of the heating resistor array.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head incorporated as a printer mechanism for a word processor, a facsimile, or the like.

[0002]

2. Description of the Related Art Conventionally, a thermal head incorporated as a printer mechanism such as a word processor includes a head substrate 11 provided with a heating resistor array 12 comprising a plurality of heating resistors on an upper surface as shown in FIG. The thermal head has a structure in which the ink ribbon I and the recording paper P are superposed on each other by using an adhesive or the like to place and fix the ink ribbon I at a predetermined position on the upper surface of a heat radiating plate 13 made of metal such as aluminum. Is transported onto the heating resistor array 12 with the ink ribbon I positioned on the head substrate 11 side, and the heating resistors are individually and selectively heated in accordance with a print signal from the outside. The heat of the ink ribbon I is heated and melted by the applied heat, and is transferred to the recording paper P using an external platen or the like, so that a predetermined print is formed. It is adapted to growth.

In such a conventional thermal head, the reverse transfer phenomenon of the ink, that is, when the ink transferred from the ink ribbon I to the recording paper P cools to some extent and starts to solidify, the ink is transferred to the ink ribbon I side again. In some cases, the heating resistor array 1
2 is arranged as close as possible to the edge of the head substrate 11 so that the ink ribbon I is scratched by the edge of the head substrate 11 while the ink of the ink ribbon I is being melted, so that the ink ribbon I is quickly peeled off the recording paper P. ing.

The heat radiating plate 13 supports the head substrate 11 on its upper surface, and absorbs part of the heat in the head substrate 11 and dissipates it into the atmosphere, so that the temperature of the head substrate 11 becomes excessive. This is to prevent the temperature from becoming high, and a conventionally known die-casting method, that is, heating and melting an ingot (a lump) of aluminum or the like, pouring it into a predetermined mold, cooling it, and then cooling the mold It was made by taking it out.

Further, on the upper surface of such a heat sink 13,
A ridge for positioning the head substrate 1 by abutting the end surface of the head substrate 11 so that the head substrate 11 can be accurately and easily placed at a predetermined position on the upper surface of the heat sink 13 when assembling the thermal head. 13a was provided.

[0006]

However, when the heat radiating plate 13 of the thermal head is manufactured by the die casting method as described above, the heat radiating plate 13 is formed inside the mold in order to make it easy to take out the heat radiating plate 13 from the mold. All the corners are provided with R surfaces having a radius of curvature of about 0.1 to 2.0 mm, so that the corners of the heat sink 13 also have predetermined R surfaces according to the internal shape of the mold. It is formed. Since such an R surface is also formed between the upper surface of the heat radiating plate 13 and the ridge 13a, it is desired to mount the head substrate 11 on the heat radiating plate 13 to assemble the thermal head. The edge of the lower surface of the head substrate 11 hits the above-mentioned R surface, and as a result, the end surface of the head substrate 11 cannot be brought into good contact with the wall surface of the ridge 13a. It had the drawback of getting worse.

Therefore, in order to solve the above-mentioned drawback, a groove is formed along the ridge 13a inside the ridge 13a on the upper surface of the heat radiating plate, and when the R surface hits the edge of the lower surface of the head substrate 11 by this groove. It has been suggested that this be done.

However, when grooves are formed along the protrusions 13a inside the protrusions 13a on the upper surface of the heat radiating plate as described above, the grooves are formed along the edges of the head substrate 11 in the heating resistor array. 12, the flow of heat from the head substrate 11 to the heat radiating plate 13 is blocked by the groove. As a result, while printing is repeated for a long time, the temperature of the head substrate 11 becomes excessively high, which causes a drawback that density unevenness and unnecessary printing are formed on the recording paper P.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks. In the thermal head of the present invention, a heating resistor array comprising a plurality of heating resistors is provided along one side of an upper surface. In a thermal head having a head substrate mounted on a heat radiating plate, an end surface of the head substrate is brought into contact with a region located on the upper surface of the heat radiating plate and located outside both ends of the heating resistor row, thereby forming a head substrate. And a groove portion formed immediately below the inside of the stop portion.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 1 is a perspective view showing one embodiment of the thermal head of the present invention, FIG. 2 is a side view of the thermal head of FIG. 1 viewed from the X direction, and FIG. 3 is a side view of the thermal head of FIG. 1 viewed from the Y direction. In addition, 1 is a head substrate, 2 is a heating resistor array, 3 is a heat sink, 3a is a stop portion, and 3b is a groove portion.

The head substrate 1 has a structure in which a heating resistor array 2 is attached along one side of a rectangular upper surface.

The heating resistor array 2 is composed of a plurality of heating resistors 2a arranged in a straight line.
Since each of the heating resistors 2a is formed of an electric resistance material such as tantalum nitride, when external power is applied through a conductive layer or the like (not shown), Joule heat is generated, and the ink of the ink ribbon I is heated. At a predetermined temperature necessary for melting the metal, for example, 200 to 400C.

The reason why the heating resistor array 2 is formed along one side of the upper surface of the head substrate 1 as described above is that the distance between the heating resistor array 2 and the edge of the head substrate 1 is increased. This is to shorten the ink ribbon I so that the ink ribbon I can be quickly peeled off the recording paper P, thereby effectively preventing the reverse transfer phenomenon of the ink described in the section of the prior art.

Such a head substrate 1 is first made of an insulating substrate made of alumina ceramics (thickness: 0.5 to 2.0 μm).
m) is prepared, and an electric resistance material such as tantalum nitride is applied on the upper surface thereof in a predetermined pattern by a conventionally known sputtering method or photolithography technique to form a plurality of heating resistors 2a.

The head substrate 1 is mounted and fixed on the upper surface of a heat sink 3 made of metal such as aluminum.

The heat radiating plate 3 has a head substrate 1 on its upper surface.
And absorbs some of the heat in the head substrate 1 and dissipates it into the atmosphere, thereby
In order to prevent the temperature of the heat sink 3 from becoming excessively high, the upper surface of the heat sink 3 is further provided with a stop portion 3a in a region located outside both ends of the heating resistor row 2. And a groove 3b are formed respectively.

The impact portion 3a is, for example, a head substrate 1
When the thickness of the head substrate is 1 mm, it is formed so as to protrude from the both ends of the heating resistor row 2 one by one at a height of 0.5 to 1.0 mm. A positioning member for positioning the head substrate 1 by abutting the end surface of the head substrate 1 along the heating resistor array 2 on the wall surface when assembling the thermal head by mounting the thermal substrate 1 on the upper surface of the heat sink 3 Acts as

On the other hand, the groove portion 3b is located outside the both ends of the heating resistor row 2 and inside the above-mentioned stop portion 3a, specifically, in the region of the upper surface of the heat sink where the head substrate 1 is placed. It is formed with a depth of 1.0 to 2.0 mm and a width of 1.0 to 3.0 mm, one by one in proximity to the stop portion 3a,
The groove 3b is formed so that an end portion of the head substrate 1 can be satisfactorily abutted on the stop portion 3a by eliminating a corner from between the stop portion 3a and the upper surface of the heat sink 3. The effect of improving the alignment accuracy of the substrate 1 is provided.

Further, since the groove 3b is provided only in a region outside both ends of the heating resistor array 2, the groove 3b does not block the conduction of heat from the head substrate 1 to the heat radiation plate 3. Without any arrangement, the lower surface of the head substrate 1 can be satisfactorily brought into contact with the upper surface of the radiator plate 3 over the region immediately below the heating resistor array 2. Therefore, the heat in the head substrate 1 is well conducted to the heat radiating plate 3 side, and the temperature of the head substrate 1 is effectively prevented from becoming excessively high. Good prints can be formed.

In this case, the stopper 3a is formed on the downstream side of the head cover 1 in the transport direction of the ink ribbon I or the like so as to be orthogonal to the transport direction. Even if an attempt is made to move the ink ribbon I or the like from a predetermined position on the upper surface of the heat radiating plate toward the transport direction of the ink ribbon I or the like by the external force caused by the sliding contact, the stopper portion 3a makes it difficult to effectively prevent the head substrate 1 from shifting. Can also.

Further, a corner formed at the upper end of the stopper portion 3a on the downstream side in the transport direction of the ink ribbon I or the like has an R.
If the surface or the C surface is provided, it is unlikely that the ink ribbon I comes into contact with the stopper 3a when the ink ribbon I used for printing is scratched by the edge of the head substrate 1 and peeled off from the recording paper P. Thus, the ink ribbon I can be transported more stably. Therefore, it is preferable to provide an R surface or a C surface at a corner formed at the upper end of the impact portion 3a on the downstream side in the transport direction of the ink ribbon I or the like.

The radiator plate 3 is formed by a conventionally known die-casting method, that is, an ingot of aluminum or the like.
Is heated and melted, poured into a predetermined mold, cooled, and taken out from the mold. Also,
When manufacturing the heat radiating plate 3 by such a manufacturing method, it is assumed that all the corners formed inside the mold are provided with R-faces so that the heat radiating plate 3 can be easily removed from the mold. Since all the R surfaces formed at the corners are at positions where they do not come into contact with the edge of the head substrate 1, there is no adverse effect on the alignment of the head substrate 1.

Thus, in the above-described thermal head of the present invention, the radiator plate 3 is attached to the printer main body by screwing or the like, and the ink ribbon I and the recording paper P are overlapped with each other. While being conveyed onto the heating resistor array 2 so as to be positioned on the first side, the heating resistors 2a are individually and selectively heated in accordance with a print signal from the outside, and the ink ribbon I is generated by the generated heat. Is heated and melted, and is transferred to the recording paper P using an external platen or the like to form a predetermined print.

Incidentally, the thermal head of the present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the gist of the present invention. For example, as shown in FIG. If the upper end of the stopper 3A formed outside the both ends of the heating resistor array 2 on the upper surface of the heat radiating plate is higher than the upper surface of the head substrate 1, the stopper 3A can be used as the ink ribbon I or the recording paper P. Has the advantage that the conveyance of the ink ribbon I and the recording paper P can be further stabilized.

In the above embodiment, the groove 3b provided inside the stopper 3a may be formed so as to penetrate to the lower surface of the heat sink 3.

[0026]

According to the thermal head of the present invention, the end surface of the head substrate is brought into contact with a region outside the both ends of the heating resistor array on the upper surface of the heat sink on which the head substrate is mounted. Since the stop portion for positioning and the groove portion are formed directly below the inside of the stop portion, the end surface of the head substrate is brought into good contact with the stop portion to accurately and easily position the head substrate. Can be done. In addition, since the groove is provided only in an area outside both ends of the heating resistor array, the groove does not interrupt heat conduction from the head substrate to the heat radiating plate at all, and generates heat on the lower surface of the head substrate. It is possible to make good contact with the upper surface of the heat sink over the region immediately below the resistor row. Therefore, the heat in the head substrate is well conducted to the heat radiating plate side, and the temperature of the head substrate is effectively prevented from becoming excessively high, whereby a clear and good print can be formed. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a thermal head of the present invention.

FIG. 2 is a side view of the thermal head of FIG. 1 viewed from an X direction.

FIG. 3 is a side view of the thermal head of FIG. 1 as viewed from a Y direction.

FIG. 4 is a perspective view showing a radiator plate 3 of the thermal head of FIG.

FIG. 5 is a perspective view showing another embodiment of the thermal head of the present invention.

FIG. 6 is a side view of a conventional thermal head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Head board 2 ... Heating resistor row 2a ... Heating resistor 3 ... Heat sink 3a ... Stop part 3b ... Groove part

Claims (1)

[Claims] 1. A thermal head comprising: a head substrate provided with a plurality of heating resistor arrays each including a plurality of heating resistors along one side of an upper surface; A stop portion for positioning the head substrate by bringing the end surface of the head substrate into contact with a region located outside both ends of the heating resistor row, and a groove portion formed directly below the inside of the stop portion. A thermal head characterized by the following.