JPH04296574A - Printing thermal head and its manufacture - Google Patents

Abstract

PURPOSE:To improve rapid sheet printing performance of a thermal printing head and sheet printing performance to a rough sheet. CONSTITUTION:A glazed layer 13 is formed through a thermally superior conductor layer 12 on the upper surface of an insulating substrate 10, and a resistance layer 15 is formed on the surface of this glazed layer. Further, individual electrodes 16 are formed on the upper surface of the resistance layer 13, while recessed surfaces 14, 14a are formed leading to the tip surface 10a of the insulating surface 10 in the glazed layer 13. In addition, a common electrode 17 is formed on the surfaces of the recessed surfaces 14, 14a.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a thermal print head used in facsimile machines, various printers, etc., which is particularly suitable for printing on so-called rough paper with large surface irregularities, and is also suitable for high-speed printing. , and a method for manufacturing the same.

0002

[Prior Art] In order to make a thermal print head suitable for printing on rough paper with large surface irregularities and for high-speed printing, the heat generating part should be placed as close as possible to the tip surface of the insulating substrate, and the heat generating part should be removed from the heat generating part. It is necessary to improve heat dissipation.

Therefore, a conventional thermal print head of this type is described in, for example, Japanese Patent Application Laid-Open No. 63-252756, and is constructed as shown in FIGS. 12 and 13. That is, a ceramic insulating substrate 1
A glaze layer 2 is formed in a semicircular shape on a portion of the surface adjacent to the tip surface 1a of the insulating substrate 1, and a thin film-like resistance layer 3 is formed over the surface of this glaze layer 2 and the surface of the insulating substrate 1. On the surface of this resistance layer 3, a large number of thin film-like individual electrode bodies 4 are formed such that each individual electrode body 4 extends toward the tip surface 1a of the insulating substrate 1. A thin film-like common electrode body 5 is provided on a portion of the surface of the layer 3 adjacent to the tip surface 1a.
By forming the common electrode body 5 so as to extend along the tip surface 1a, a portion of the resistance layer 3 where each of the individual resistors 4 and the common electrode body 5 are formed is formed into a heat generating portion 6; Furthermore, a heat dissipation plate 7 made of a good thermal conductor such as an aluminum alloy is placed in close contact with the back surface of the insulating substrate 1. Note that the reference numeral 8 is a protective film made of glass or the like.

0004

[Problems to be Solved by the Invention] However, in this conventional thermal print head, the presence of the common electrode body 5 in the region between the tip end surface 1a and the heat generating part 6 on the insulating substrate 1 causes the above-mentioned If the dimension S from the tip surface 1a to the heat generating section 6 is made smaller so that each of the heat generating sections 6 is brought closer to the tip surface 1a, the width dimension W of the common electrode body 5 must naturally be narrowed. First, there is a problem in that the electric resistance in the common electrode body 5 increases and the voltage drop increases, so that it cannot be applied to a device with a large number of heat generating parts 6, that is, a large number of dots. Further, the heat generated in each of the heat generating parts 6 escapes to the heat sink 7 via the glaze layer 2 and the insulating substrate 1, but the glaze layer 2 and the insulating substrate 1 are both poor conductors of heat. Another problem was that it had poor heat dissipation properties, making it less suitable for high-speed printing.

The technical object of the present invention is to provide a high-speed application type thermal print head that solves this problem, as well as to provide a method for manufacturing the same.

[0006]

[Means for Solving the Problems] In order to achieve this technical problem, the thermal print head according to claim 1 of the present invention includes an insulating substrate, a thin film resistance layer, and a large number of thin film resistance layers. In a thermal print consisting of an individual electrode body, a thin film-like common electrode body, and a heat sink in close contact with the back surface of the insulating substrate, a good thermal conductor layer such as silver or aluminum is sandwiched on the surface of the insulating substrate. A glaze layer is formed, and the resistance layer is formed on the surface of the glaze layer, and the individual electrode body is formed on the surface of the resistance layer. A concave surface is provided from the distal end surface, and the common electrode body is formed in this concave surface so as to extend along the distal end surface.

[0007] Furthermore, "Claim 2" relates to a method for manufacturing the thermal print head according to Claim 1, and its gist is that a plurality of unit insulating substrates constituting one thermal print head After forming a thermally conductive layer such as silver or aluminum on the surface of the raw material board which is integrally connected, a glaze layer is formed on the surface of this thermally conductive layer, and then each of the unit insulating substrates is At the boundary portion, grooves for cracking the material body for each unit insulating substrate are carved at a depth such that the grooves reach the material plate beyond the glaze layer and the thermally conductive layer, Next, after forming a thin film-like resistance layer on the surface of the glaze layer, a large number of thin film-like individual electrode bodies are formed on the surface of this resistance layer, and further, both left and right groove surfaces in the streak groove are formed. Another method is to form a thin film-like common electrode body so as to extend along the longitudinal direction of the grooves, and then crack the material plate for each unit insulating substrate along the grooves.

[0008]

Effects and Effects of the Invention As in claim 1, a glaze layer is formed on the surface of an insulating substrate with a good thermal conductor layer such as silver or aluminum sandwiched therebetween, and the resistor is formed on the surface of the glaze layer. By forming a layer and further forming a large number of individual electrode bodies on the surface of this resistance layer, the heat generated in each heat generating part between each individual electrode body and the common electrode body is The heat is transmitted through the glaze layer to the thermally conductive layer formed between the glaze layer and the insulating substrate, and is radiated from this thermally conductive layer to the atmosphere, and the thermally conductive layer is transmitted through the insulating substrate to the thermally conductive layer. Since the heat can also escape to the heat dissipation plate on the back surface, the heat dissipation from each of the heat generating parts can be greatly improved. Moreover, a recessed surface from the end surface of the insulating substrate in the glaze layer is provided, and the common electrode body is formed in this recessed surface so as to extend along the end surface. By doing so, the width dimension of the common electrode body can be increased in the thickness direction of the glaze layer. Each heat generating part between this common electrode body and each of the individual electrode bodies can be formed without narrowing the dimensions.
It can be brought close to the tip end surface of the insulating substrate.

Therefore, according to Claim 1, the high-speed printing performance of the thermal print head can be greatly improved, and the printing performance on rough paper with large surface irregularities can be reliably improved even when the number of dots is large. It has an effect that can be improved.

[0010] Furthermore, according to the manufacturing method of "Claim 2",
By carving grooves in the material for cracking the material plate for each unit insulating substrate, the grooves simultaneously form a concave surface from the tip of the insulating substrate against the glaze layer. At the same time, multiple thermal print heads can be manufactured from a single material board, making it possible to manufacture thermal print heads with high-speed printing performance and printing performance on rough paper at low cost. It has the effect of

[0011]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show an embodiment of claim 1,
In this figure, reference numeral 10 denotes a ceramic insulating substrate constituting one thermal print head A, and a heat sink 11 made of aluminum alloy is in close contact with the lower surface of the insulating substrate 10.

A thermally conductive layer 12 such as silver or aluminum is formed to an appropriate thickness on the upper surface of the insulating substrate 10, and further,
A glaze layer 1 of an appropriate thickness is placed on the upper surface of this thermally conductive layer 12.
3, while forming the tip surface 10 of the insulating substrate 10 of the glaze layer 13 and the thermally conductive layer 12.
At part a, there is an inclined concave surface 1 from this tip surface 10a.
4 will be provided.

[0013] Then, a thin film-like resistance layer 15 is formed on the upper surface of the glaze layer 13, and the resistance layer 15 is formed on the recessed surface 14.
Further, a large number of thin film-like individual electrode bodies 16 are formed on the upper surface of this resistance layer 15 so that each individual electrode body 16 extends toward the tip surface 10a. Further, a thin film-like common electrode body 17 is formed on the surface of the resistive layer 15 at the concave surface 14 so that the common electrode body 17 extends along the tip surface 10a. A heat generating portion 18 is formed between the electrode body 17 and each of the individual electrode bodies 16. Note that the reference numeral 19 is a protective film made of glass or the like.

As described above, the glaze layer 13 is formed on the upper surface of the insulating substrate 10 with the thermally conductive layer 12 such as silver or aluminum sandwiched therebetween, and the resistive layer 1 is formed on the upper surface of the glaze layer 13.
5 and furthermore, a large number of individual electrode bodies 16 are formed on the surface of this resistance layer 15, so that each heat generating portion 18 between each individual electrode body 16 and the common electrode body 17 The generated heat is transmitted through the glaze layer 13 to the thermally conductive layer 12 formed between the glaze layer 13 and the insulating substrate 10, and is radiated from this thermally conductive layer 12 into the atmosphere. Since heat escapes from the heat conductor layer 12 via the insulating substrate 10 to the heat dissipation plate 11 on the back surface thereof, the heat dissipation from each of the heat generating parts 18 can be greatly improved.

Further, a recessed surface 14 that is inclined from the end surface 10a of the insulating substrate 10 of the glaze layer 13 and the thermally conductive layer 12 is provided with a recessed surface 14 that is inclined from the end surface 10a. By forming the common electrode body 17 to extend along the tip surface 10a, the width dimension of the common electrode body 17 can be increased in the thickness direction of the glaze layer 13. With the width dimension of the common electrode body 17 secured, in other words, without narrowing the width dimension of the common electrode body 17, each heat generating portion 18 between this common electrode body 17 and each of the individual electrode bodies 16 is From, the tip surface 1
The dimension S up to 0a can be made smaller than in the conventional case.

[0016] Note that the concave surface 14 from the tip surface 10a
Instead of being formed in an inclined shape, as shown in FIG. 3, it may be formed in a concave surface 14a that is approximately parallel to the tip surface 10a, and as in the illustrated embodiment,
By forming the concave surfaces 14 and 14a to extend to the portion of the thermally conductive layer 12, the resistance layer 15 and the common electrode body 16 are extended to the thermally conductive layer 12, and the thermally conductive layer 16 is extended. When the common electrode body 16 is made of a good electrical conductor such as silver or aluminum, the common electrode body 16 becomes
It is electrically conductive to the thermally conductive layer 16, which is a good electrical conductor.In other words, the thermally conductive layer 16 can also be used as a common electrode, so that the voltage drop in the common electrode 16 is reduced. It has the advantage of being able to further reduce

Further, FIGS. 4 to 11 show an embodiment of a method for manufacturing the thermal print head A described above. First, as shown in FIG. 4, a material plate 20 is prepared, in which a plurality of unit insulating substrates 10 (four in this embodiment) that constitute one thermal print head A are integrally connected.
On the upper surface of this material plate 20, as shown in FIGS. 5 and 6,
A thermally conductive layer 12 made of silver or the like is formed to an appropriate thickness, and then a glaze layer 13 is formed to an appropriate thickness on the upper surface of this thermally conductive layer 12. The thermally conductive layer 12 is formed by applying silver paste to an appropriate thickness on the upper surface of the material plate 20, and then heating and baking it. Further, the glaze layer 13 is also formed by applying glass paste to an appropriate thickness on the upper surface of the thermally conductive layer 12 and then heating and baking it.

Next, as shown in FIGS. 7 and 8, a V-shaped or U-shaped cross section is formed at the boundary between the unit insulating substrates 10 for cracking the material plate 20 one by one. The grooves 21 extend over the glaze layer 13 and the thermally conductive layer 12 into the material plate 2.
Carve to a depth that reaches 0. In this case, both the left and right groove surfaces 21a, 21b of the groove 21 become the concave surfaces 14, 14a in FIGS. 1 and 3.

Then, as shown in FIG. 9, a thin film-like resistance layer 15 is placed on the upper surface of the glaze layer 13.
5 indicates both left and right groove surfaces 21a and 21b in the groove groove 21.
10, a plurality of individual electrode bodies 16 are formed on the upper surface of this resistance layer 15, while forming both left and right grooves in the grooves 21 of the resistance layer 13. A common electrode body 17 is formed on the surfaces of the surfaces 21a and 21b so as to extend along the grooves 21.

[0020] Next, as shown by the chain double-dashed line,
After forming a protective film 19 such as glass, the material plate 20
As shown in FIG. 11, by cracking each unit insulating substrate 10 at each groove 21, a plurality of (four in this example) thermal print heads A are produced from one material board 20. can be manufactured.

[Brief explanation of drawings]

FIG. 1 is an enlarged longitudinal sectional front view of a thermal print head according to a first embodiment of the present invention.

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is an enlarged longitudinal sectional front view of a thermal print head according to a second embodiment of the present invention.

FIG. 4 is a perspective view of a material plate.

FIG. 5 is a perspective view when a thermally conductive layer and a glaze layer are formed on the material plate.

FIG. 6 is an enlarged sectional view taken along VI-VI in FIG. 5;

FIG. 7 is a perspective view when grooves are carved.

FIG. 8 is an enlarged sectional view taken along line VIII-VIII in FIG. 7;

FIG. 9 is an enlarged cross-sectional view when forming a resistance layer.

FIG. 10 is an enlarged cross-sectional view when forming individual electrode bodies and a common electrode body.

FIG. 11 is an enlarged cross-sectional view when the material plate is cracked into unit insulating substrates.

FIG. 12 is an enlarged longitudinal sectional front view of a conventional thermal print head.

FIG. 13 is a plan view of FIG. 12;

[Explanation of symbols]

A Thermal print head 10 Insulating substrate 10a
Tip surface 11 of insulating substrate
Heat sink 12 Heat conductor layer 13
Glaze layer 14, 14a Concave surface 15 Resistance layer 16 Individual electrode body 17
Common electrode body 18
Heat generating part 19 Protective film 20 Material plate 21 Groove

Claims (2)

[Claims] 1. A thermal print comprising an insulating substrate, a thin film resistance layer, a large number of thin film individual electrode bodies, a thin film common electrode body, and a heat sink in close contact with the back surface of the insulating substrate. forming a glaze layer on the surface of the insulating substrate with a thermally conductive layer such as silver or aluminum sandwiched therebetween;
The resistive layer is formed on the surface of the glaze layer, and the individual electrode body is formed on the surface of the resistive layer, while a portion of the glaze layer at the tip of the insulating substrate,
A thermal print head characterized in that a concave surface is provided from the tip surface, and the common electrode body is formed in this concave surface so as to extend along the tip surface. [Claim 2] After forming a thermally conductive layer such as silver or aluminum on the surface of a material plate which is made by integrally connecting a plurality of unit insulating substrates constituting one thermal print head, A glaze layer is formed on the surface of the thermally conductive layer, and then grooves for cracking the material plate for each unit insulating substrate are formed at the boundary between the unit insulating substrates, and the grooves are formed in the glaze layer. Then, a thin film-like resistance layer is formed on the surface of the glaze layer. After forming a thin film individual electrode body and further forming a thin film common electrode body on both left and right groove surfaces of the groove so as to extend along the longitudinal direction of the groove, the raw material plate is A method for manufacturing a thermal print head characterized by cracking each unit insulating substrate along the grooves.