JP2592159Y2 - Thermal head - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a thermal head incorporated in a printer mechanism such as a word processor or a facsimile.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a thermal head incorporated in a printer mechanism such as a word processor has a heating element 12 made of tantalum nitride or the like and a pair of conductive layers made of aluminum or the like connected to the heating element 12 as shown in FIG. 1
3 is mounted on a metal heat radiating plate 14 made of aluminum or the like, and a predetermined electric power is applied between the pair of conductive layers 13. By applying the heat, the heating element 12 is selectively caused to generate Joule heat in response to an external electric signal, and the generated heat is conducted to heat-sensitive paper or the like to form a printed image on the heat-sensitive paper or the like, thereby functioning as a thermal head. .

The head substrate 11 and the metal heat sink 1
4, a resin material 15 made of silicon grease or the like is interposed, and the resin material 15 causes the head substrate 11 to adhere to the metal radiator plate 14 and transfers the heat of the head substrate 11 to the metal radiator plate 14. The temperature of the entire head substrate 11 is made uniform by stably conducting and absorbing. A screw hole 14 for screwing and fixing the thermal head to the printer mechanism is provided in the thickness direction of the metal heat sink 14.
The screw hole 14a is generally formed by penetrating the metal heat radiating plate 14 in order to facilitate drilling and threading.

[0004]

However, in this conventional thermal head, since the resin material 15 is made of silicon grease having fluidity, the head is placed on the metal radiator plate 14 via the resin material 15. When mounting the substrate 11 and assembling the thermal head, depending on the weight of the head substrate 11, the resin material 15 is screwed into the screw hole 1 of the metal heat sink 14.
4a, and adheres to the inner periphery of the screw hole 14a. As a result, the screw 16 cannot be screwed into the screw hole 14a, and the thermal head is firmly attached to the printer mechanism. Had the drawback that it could not be done.

[0005]

The object of the present invention was made in view of the above-mentioned drawbacks. The purpose of the present invention is to effectively prevent the resin material from adhering to the inner periphery of the screw hole of the metal radiator plate, and to reduce the screw to the screw hole. It is an object of the present invention to provide a thermal head that can be screwed into the back.

[0006]

The thermal head according to the present invention is a thermal head comprising a head substrate having a heating element attached to an upper surface thereof, mounted on a metal radiator plate via a resin material. The metal heat radiating plate has a screw hole penetrating in the thickness direction thereof, and a concave space for accommodating an excess of the resin material is formed around an opening of the screw hole on the head substrate side. It is characterized by being.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view showing an embodiment of the thermal head according to the present invention, and FIG. 2 is a sectional view taken along line XX of FIG.
Is a head substrate, 2 is a heating element, 3 is a pair of conductive layers, 4 is a metal radiator plate, 4a is a screw hole provided in the metal radiator plate 4,
5 is a resin material.

The head substrate 1 is made of an electrically insulating material such as alumina ceramics. A plurality of heating elements 2 are provided on the upper surface of the head substrate 1 via a heat storage layer 1a made of glass or the like. A conductive layer 3 is applied.

When the head substrate 1 is made of, for example, alumina ceramics, a ceramic material powder of alumina, silica, magnesia or the like is mixed with an appropriate organic solvent and a solvent to form a slurry, which is formed into a slurry by a conventionally known doctor blade. The ceramic green sheet is formed by employing a method, a calendar roll method, or the like, and thereafter, the ceramic green sheet is punched into a predetermined shape and fired at a high temperature (about 1600 ° C.).

On the upper surface of the head substrate 1, a heat storage layer 1a made of glass or the like is adhered. The heat storage layer 1a accumulates the heat generated by the heating element 2 and reduces the temperature of the thermal head in a short time. It has the function of setting the temperature necessary for forming a print image on paper or the like.

The heat storage layer 1a is formed by applying a glass paste obtained by adding and mixing an appropriate organic solvent to glass powder to a predetermined region on the upper surface of the head substrate 1 by employing a conventionally known screen printing method or the like. Thereafter, this is attached to the upper surface of the head substrate 1 by baking it at a high temperature, for example, a temperature of about 700 ° C.

A plurality of heating elements 2 are also arranged on the upper surface of the heat storage layer 1a, and a pair of conductive layers 3 are connected to each heating element 2.

The heating element 2 is made of, for example, tantalum nitride or the like, and has a predetermined electric resistivity. Therefore, when power is applied through a pair of conductive layers 3, Joule heat is generated, and printing is performed. The temperature required to form the image,
For example, heat is generated at a temperature of 250 to 400 ° C.

The pair of conductive layers 3 connected to the heating element 2 are made of a metal such as aluminum, and have a function of applying a predetermined electric power necessary for causing the heating element 2 to generate Joule heat.

The heating element 2 and the pair of conductive layers 3
Is applied on the head substrate 1 with a predetermined thickness by employing a conventionally known sputtering method or the like, and is further processed into a predetermined pattern by employing photolithography technology.

The heating element 2 and the pair of conductive layers 3 are further provided with a protective layer 6 on the upper surface thereof.
Acts to protect the heating element 2 and the pair of conductive layers 3 from abrasion due to sliding contact with thermal paper or the like and corrosion due to contact with moisture or the like contained in the atmosphere.

The protective layer 6 is made of, for example, silicon nitride, sialon, or the like, and is adhered to the upper surface of the heating element 2 or the like with a predetermined thickness by employing a conventionally known sputtering method or the like.

The head substrate 1 having the heating element 2 and the like adhered to the upper surface is mounted on a metal heat radiating plate 4 via a resin material 5.

The resin material 5 interposed between the head substrate 1 and the metal heat radiating plate 5 is made of silicon grease, epoxy resin, or the like. And the heat of the head substrate 1 is stably conducted and absorbed by the metal radiating plate 4 to bring the temperature of the entire head substrate 1 into a uniform temperature state.

The resin material 5 is formed, for example, by applying silicon grease on the upper surface of the metal radiator plate 5 to a predetermined thickness (approximately 1
0 to 50 μm), and thereafter, the head substrate 1 is placed on the metal radiator plate 5 so that the head substrate 1
And a metal heat sink 5.

The metal heat radiating plate 4 on which the head substrate 1 is mounted is made of, for example, aluminum or the like, and conducts and absorbs a part of the heat of the head substrate 1 and radiates it to the atmosphere. Has an effect of effectively preventing an excessively high temperature due to the heat generated by the heating element 2.

The metal radiating plate 4 is manufactured by forming an ingot (lumps) made of aluminum or the like into a predetermined shape by using a conventionally known metal working method.

The metal heat radiating plate 4 also has a screw hole 4a penetrating in the thickness direction thereof, and the inner periphery of the screw hole 4a is threaded.

The screw holes 4a having the inner periphery threaded therein are for fixing the thermal head to the printer mechanism with screws. The thermal head is attached to the printer mechanism by fixing the thermal head to the lower surface of the printer with screws 8a screwed into the screw holes 4a.

Further, in the through hole 4a, a recess A for accommodating a surplus of the resin material 5 is formed around the opening on the side where the head substrate 1 is mounted. ,
When assembling the thermal head by mounting the head substrate 1 on the metal heat radiating plate 4, even if the resin material 5 flows out in the screw hole 4 a direction of the metal heat radiating plate 4 due to the weight of the head substrate 1, it flows out. The resin material 5 only flows into the recess A formed around the opening of the screw hole 4a and does not adhere to the inner periphery of the screw hole 4a. Therefore, when the thermal head is screwed and fixed to the printer mechanism, the screw 8a can be screwed sufficiently into the screw hole 4a, thereby making it possible to firmly attach the thermal head to the printer mechanism. .

The recess A formed in the screw hole 4a has a depth d of 0.5 to 5.0 mm and a width w of 2.0 to 10.0 mm. A sufficient space for accommodating the resin material 5 flowing out to A is formed. Even when the resin material 5 flows out when the head substrate 1 is mounted on the metal heat dissipation plate 4, the resin material 5 remains in the recessed space. A completely does not flow into the inner periphery of the screw hole 4a because it is completely accommodated in A. Therefore, it is preferable that the depth d of the recess A is 0.5 to 5.0 mm and the width w of the screw hole 4a is 2.0 to 10.0 mm.

The recess A formed in the screw hole 4a may be provided with a protrusion C having a height of 0.5 to 5.0 mm at a portion of the inner wall thereof which comes into contact with the screw hole 4a. C effectively blocks the resin material 5 flowing into the concave space A from flowing into the screw hole 4a, and reliably prevents the resin material 5 from adhering to the inner periphery of the screw hole 4a. Therefore,
It is preferable to provide a projection C having a height of 0.5 to 5.0 mm at a portion of the inner wall of the recess A formed in the screw hole 4a and in contact with the screw hole 4a.

Further, the concave space A is formed by drilling a hole using an end mill from the upper surface side of the metal heat radiating plate 4 having the screw hole 4a so as to be concentric with the inner periphery of the screw hole 4a. The hole 4a is formed around the opening on the side on which the head substrate 1 is placed.

Thus, in the thermal head of the present invention, a predetermined power is applied between the pair of conductive layers 3 to cause the heating element 2 to selectively generate Joule heat in accordance with an external electric signal, and to release the generated heat from the head. Conduction is performed on a thermal paper or the like that slides on the substrate 1 to form a printed image on the thermal paper or the like, thereby functioning as a thermal head.

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. 4, a screw hole 4a different from the screw hole 4a for screwing and fixing the thermal head to the printer mechanism.
b is provided so as to penetrate in the thickness direction of the metal heat sink 4, and a temperature detecting element 9 such as a thermistor is inserted into the screw hole 4b, and the temperature detecting element 9 is screwed into the screw hole 4b with a screw 8b. When the temperature detecting element 9 is contacted with the lower surface of the head substrate 1 to overheat the thermal head during continuous use of the thermal head or to control the temperature, a screw hole is used. When a concave space B is formed around the opening on the side on which the head substrate 1 of 4b is mounted, when the head substrate 1 is mounted on the metal radiating plate 4 and the thermal head is assembled, the weight of the head substrate 1 is reduced. As a result, even if the resin material 5 flows in the screw hole 4b direction, the resin material 5 that has flowed out flows into the recess B formed around the opening of the screw hole 4b and adheres to the inner periphery of the screw hole 4b. Never do In order to detect the temperature of the head substrate 1 accurately, the screw 8b can be screwed sufficiently into the screw hole 4b, and the temperature detecting element 9 can be kept in close contact with the lower surface of the head substrate 1. At the same time, overheating detection and the like during continuous use of the thermal head can be performed extremely accurately. The temperature detecting element 9
9a for connecting the wire to an external electric circuit (not shown)
By providing a predetermined groove in the inner periphery of the screw hole 4b and burying the lead wire 9a in the groove,
b can be led out from the lower surface of the metal heat sink 4 without hindering the screw 8b from being screwed into the heat sink b.

Therefore, the screw holes 4a for screwing and fixing the thermal head to the printer mechanism are formed in the metal radiating plate 4.
A separate screw hole 4b is provided to penetrate in the thickness direction of the metal heat sink 4, and the temperature detecting element 9 is urged toward the head substrate 1 by a screw 8b screwed into the screw hole 4b.
When the temperature detecting element 9 contacts the lower surface of the head substrate 1 to detect overheating or temperature control during continuous use of the thermal head by the temperature detecting element 9, the side of the screw hole 4b on which the head substrate 1 is placed. It is preferable to form the recessed portion B around the opening of the above.

[0033]

According to the thermal head of the present invention, a screw hole penetrating in the thickness direction of the metal heat sink is provided, and a concave space is formed around the opening of the screw hole on the side on which the head substrate is mounted. As a result, when the head substrate is placed on the metal heat sink and the thermal head is assembled, even if the resin material flows out in the screw hole direction of the metal heat sink due to the weight of the head substrate, The material only flows into the concave space formed around the opening of the screw hole, and does not adhere to the inner periphery of the screw hole. Accordingly, when the thermal head is screwed and fixed to the printer mechanism, the screw can be screwed sufficiently into the screw hole, whereby the thermal head can be firmly attached to the printer mechanism.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a thermal head according to the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a sectional view showing another embodiment of the thermal head of the present invention.

FIG. 4 is a sectional view of a conventional thermal head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Head board 2 ... Heating element 3 ... A pair of conductive layers 4 ... Metal radiator plate 4a, 4b ... Screw hole 5 ... Resin material 6 ... Protective layer 8a. 8b: Screw 9: Temperature detection element 9a: Lead wire A, B: Concavity C: Projection

Claims (1)

(57) [Scope of request for utility model registration] 1. A thermal head comprising a head substrate having a heating element attached to an upper surface thereof mounted on a metal radiator plate via a resin material, wherein the metal radiator plate has a thickness direction. A thermal head, comprising: a screw hole that penetrates through the hole; and a recessed portion for accommodating an excess of the resin material is formed around an opening of the screw hole on the head substrate side.