JP2002370399A - Thermal head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal head of such a structure that thermal interference is suppressed between two arrays of heating resistor while facilitating manufacture and the yield of manufacture is increased using a substrate material causing no cracking at the time of heat treatment. SOLUTION: The thermal head comprises a substrate 41 (71) on which an elongated protrusion 42 is formed in the main scanning direction, a plurality of heating resistors 14 arranged in the main scanning direction on one side of the protrusion 42, a plurality of heating resistors 24 arranged in the main scanning direction on the other side of the protrusion 42, a partial glaze glass 52 on the primary electrode side inserted between the heating resistor 14 and the substrate 41, a region on the heating resistor 14 side of a partial glaze protrusion 52a on the primary electrode side, a partial glaze glass 62 on the secondary electrode side inserted between the heating resistor 24 and the substrate 41, and a region on the heating resistor 24 side of a partial glaze protrusion 62a on the secondary electrode side, wherein a groove 43 is made in the rear surface of the substrate 41 along the protrusion 42.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head capable of printing two lines simultaneously by two rows of heating elements, or a preheating method in which one row of the two rows of heating elements performs preheating. The present invention relates to a thermal head whose printing speed is increased by performing printing in a row.

[0002]

2. Description of the Related Art The basic structure of a conventional thermal head used for a color printer or the like is shown in FIGS. FIG. 7 shows a thermal head disclosed in Japanese Patent Application No. 62-217627. Note that FIG. 7A is a top view,
FIG. 7B is a sectional view taken along line BB ′ of FIG. 7A. In this figure, reference numerals 501a and 501b
Is a ceramic substrate. Reference numeral 517 is a common electrode protrudingly formed on the substrate for the heating resistor. FIG. 8 shows a thermal head disclosed in Japanese Patent Application No. 08-313966. 8A is a top view, and FIG. 8B is a cross-sectional view taken along line AA ′ of FIG. 8A. In this figure, reference numeral 602 denotes a metal substrate having a protrusion 603, and reference numerals 608 and 611 denote heating resistors.

FIG. 9 shows a thermal head disclosed in Japanese Patent Application No. 11-377307. FIG. 9A is a top view, and FIG. 9B is a cross-sectional view taken along the line CC ′ of FIG.
In FIG. 9, reference numeral 701 denotes a substrate formed of single crystal silicon. Reference numerals 704 and 705 denote heating resistors, and reference numeral 707 denotes a common electrode for the heating resistors 704 and 705. Reference numeral 702 denotes the common electrode 70
7, a metal conductor plating 703 is applied to the inner surface. FIG.
FIG. 65A shows the structure of a thermal head shown in FIG. 65474, in which FIG.
It is sectional drawing in the line D '. In FIG.
Reference numerals 853, 854, 863, and 864 denote heating resistors, and reference numeral 852 denotes partial glaze glass.

[0004]

In the case of the thermal head shown in FIG. 7, since the substrates 501a and 501b and the common electrode 517 have different coefficients of thermal expansion, the thermal head has a stress due to thermal stress based on Joule heat generated by the heating resistor. , The substrate 501a,
Peeling may occur at the interface between b and the common electrode 517, and the performance may be deteriorated by long-term use. Also,
In the case of the thermal head shown in FIG. 8, since a common current flows from all the heating resistors in the thermal head to the projection 603 which is a part of the substrate 602, the substrate 602 is generated by Joule heat due to the resistance of the substrate based on this current. Generates heat. Therefore, heat is not sufficiently dissipated through the substrate 602, and the accumulated heat causes heat interference between the heating resistor 608 and the heating resistor 611, and the heating resistor 60
It becomes difficult to control 8 and 611 independently.

In the case of the thermal head shown in FIG. 9, since the current flows from the heating resistor due to the metal conductor plating 703 in the through hole 702, the substrate does not generate heat and heat is radiated. Although there is no thermal interference between the heating elements, since a silicon single crystal is used for the substrate, processing of the through-holes 702 is required, and there is a disadvantage that the manufacturing process is troublesome. Further, in the case of the thermal head shown in FIG. 10, the heating resistors 853 and 854 and the heating resistors 863 and 864 are formed close to each other, and these heating resistors are formed on the partial glaze 852. Joule heat generated by the heating resistors is stored in the partial glaze, causing thermal interference between the heating resistors, making it difficult to perform independent thermal control of each heating resistor. In the thermal head of FIG. 10, in order to avoid the problem of thermal interference, a platen roller (not shown) that presses the printing paper against the head when the distance between the two rows of heating resistors is large.
The contact state between the print head and the thermal head is deteriorated, and the printing characteristics are degraded. In order to improve the contact state, it is necessary to increase the diameter of the platen roller or to increase the pressing force of the platen roller, which increases the size of the printing apparatus.

The above-described conventional thermal head shown in FIGS. 8 to 10 has a glaze made of glass in order to provide electrical insulation on a metal substrate surface and better contact of a heating resistor with printing paper. The structure which forms is taken. However, since stainless steel is used for the substrate material, in the heat treatment at the time of manufacturing, due to the difference in linear expansion coefficient between stainless steel and the glass of the material of the partial glaze, cracks occur in the partial glaze due to the concentration of this stress, For this reason, it cannot be easily formed, and there is a problem that the production yield of the thermal head is reduced. Here, the above-mentioned heat treatment refers to a process in which a glass paste is screen-printed on a substrate surface and fired at a high temperature of 1000 ° C. to produce the paste.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and has as its object to suppress thermal interference between two rows of heating resistors, facilitate manufacture, and provide heat treatment during manufacture. It is an object of the present invention to provide a thermal head having a structure that improves the production yield of products by using a substrate material that does not crack.

[0008]

A thermal head according to the present invention comprises a substrate (41, 71) on which an elongated projection (projection 42) is formed in the main scanning direction, and one side of the projection. A plurality of first heating resistors (heating resistors 14) arranged in the main scanning direction, and a plurality of second heating resistors (heating resistors) arranged in the main scanning direction on the other side of the protrusion. Body 24)
And a first insulator (primary electrode side partial glaze glass 52, 52) interposed between the first heating resistor and the substrate.
(Area of the glaze glass layer 62a on the side of the heating resistor 14)
And a second insulator (second electrode side partial glaze glass 62, interposed between the second heating resistor and the substrate).
(A region of the glaze glass layer 62a on the heating resistor 24 side), and a groove (groove 43) is formed on the back surface of the substrate along the protrusion.

[0009] In the thermal head of the present invention, the substrate may be:
The groove portion thermally separates the first heat-generating resistor region from the second heat-generating resistor region (electrode-side substrate portion 41).
a and the secondary electrode side substrate portion 41b). The thermal head according to the present invention is characterized in that the substrate is formed using a material (alumina) having a thermal expansion coefficient close to that of the first and second insulators.

In the thermal head of the present invention, a filling groove (groove portion 43 or filling groove 101) is formed on the back surface of the substrate, and the filling groove has an insulator (glass) made of the same material as the first and second insulators. 100, 102) are filled. In the thermal head according to the present invention, the protrusion absorbs heat radiated by the first and second heating resistors to the first insulator and the second insulator, respectively, and radiates the heat to the substrate. And The thermal head according to the present invention is characterized in that the first heating resistor and the second heating resistor are formed so as to be shifted from each other by ピ ッ チ pitch in the main scanning direction.

[0011]

<First Embodiment> FIG. 1 shows the configuration of a thermal head according to a first embodiment of the present invention. Note that FIG. 1A is a top view and is configured to be line-symmetric with respect to a center line QQ ′. FIG.
(B) is a sectional view taken along line DD ′ in FIG. 1 (A).

In FIG. 1, a substrate 41 is made of stainless steel, for example, has a thickness T of 0.1 to 1 mm, and has a long projection 42 on the surface thereof in the main scanning direction. The protrusion 42 is formed integrally with the substrate 41). A primary electrode-side partial glaze glass 52 and a secondary electrode-side glaze glass 62 are formed on both sides of the protrusion 42, respectively. Here, the primary electrode side partial glaze 5
The second and secondary electrode side partial glazes 52 are connected via a glaze glass layer 62 b having a predetermined thickness T above the protrusions 42.

The resistor 11 is patterned on the upper surface of the primary electrode side partial glaze glass 52 to a width corresponding to the dot density in printing, and is formed in a folded shape in the vicinity of the projection 42. The resistor 11 has one end connected to the output terminal of the control IC 19 and the other end connected to the common electrode 16. Further, in the resistor 11, an individual lead electrode 17a is formed on an upper surface of a region connected to the control IC 19, and an individual lead electrode 17b is formed on an upper surface of a region connected to the common electrode 16. An intermediate electrode 15 is formed on the upper surface of the folded portion. The intermediate electrode 15 is formed in order to prevent generation of Joule heat in the region of the folded portion of the resistor 21.

Here, the one end of the resistor 11 is connected to the output terminal of the control IC 19 via the individual lead electrode 17a and the bonding wire 18. The other end of the resistor 11 is connected to the common electrode 16 via the individual lead electrode 17b. The area of the resistor 11 between the individual lead electrode 17a and the intermediate electrode 15 becomes the heating resistor 13a.
The area of the resistor 11 between the electrode b and the intermediate electrode 15 becomes the heating resistor 13b. Further, in the following description, the heating resistor 13a and the heating resistor 13b are collectively paired,
That is, the heating resistor 14 may be represented as one dot. Further, on the surface of the primary electrode side partial glaze 52, a primary electrode side partial glaze protrusion 52a is formed at a position corresponding to a lower portion of the heating resistor 14.

On the other hand, the resistor 21 is patterned on the upper surface of the secondary electrode side partial glaze glass 62 to have a width corresponding to the dot density in printing, and is formed in a folded shape in the vicinity of the projection 42. The resistor 21 has one end connected to the output terminal of the control IC 29 and the other end connected to the common electrode 26. Further, the resistor 21
The individual lead electrode 27a is formed on the upper surface of the region connected to the control IC 29, the individual lead electrode 27b is formed on the upper surface of the region connected to the common electrode 26, and the upper surface of the folded portion is formed. The intermediate electrode 25
Are formed. The intermediate electrode 25 is formed in order to prevent generation of Joule heat in the region of the folded portion of the resistor 21.

Here, the one end of the resistor 21 is connected to an output terminal of the control IC 29 via an individual lead electrode 27a and a bonding wire 28. The other end of the resistor 21 is connected to the common electrode 28 via the individual lead electrode 27b. The area of the resistor 21 between the individual lead electrode 27a and the intermediate electrode 15 becomes the heating resistor 23a.
The area of the resistor 21 between the electrode b and the intermediate electrode 25 becomes the heating resistor 23b. In the following description, the heating resistor 23a and the heating resistor 23b are collectively paired,
That is, the heating resistor 24 may be represented as one dot. Further, on the surface of the secondary electrode side partial glaze 62, a secondary electrode side partial glaze protrusion 62a is formed at a position corresponding to a lower portion of the heating resistor 24.

With the above-described configuration having the resistor 11 (or 21) folded back, one end and the other end of the resistor 11 are connected.
One electrode can be drawn out in the same direction (outside of the thermal head, that is, in the direction of the control IC), and two heating resistors can be associated with the same dot. On the back surface of the substrate 41, a V-shaped groove 43 is formed along the projection 42, for example, with a depth H of 0.05 to 0.8 mm and a width of 0.05 to 1 mm. And radiating fins (not shown) are provided. The groove 43 is formed by a technique such as etching or laser processing. Here, as the width W of the opening of the groove 43, a numerical value corresponding to the depth H of the groove 43 is selected as appropriate.

With the above configuration, the control IC
19 (or the control IC 29), the on / off operation of the transistor incorporated therein causes the heating resistor 14
The Joule heat generated by the heating resistor (or the heating resistor 24) is controlled, and a printing operation is performed on the printing paper by sublimating the ink on the color ink ribbon. The control ICs 19 and 29 are respectively composed of the heating resistors 14 and 2
The heating resistors 1 are provided in a number corresponding to the number of the heating resistors 1, respectively, based on data supplied from a power supply (not shown) based on data from a control device of a printer (not shown).
4, 24 are driven. Then, of the Joule heat generated by each of the heat generating resistors 14 and 24, the heat conducted to the primary electrode side partial glaze glass 52 and the heat conducted to the secondary electrode side partial glaze glass 62 41
And is radiated into the atmosphere by radiation fins (not shown) through the primary electrode side partial glaze glass 52 and the secondary electrode side partial glaze glass 62, that is, the heating resistors 14 and 2.
4 is cooled.

The protruding portion 42 acts as a barrier to heat between the primary electrode side partial glaze glass 52 and the secondary electrode side partial glaze glass 52, and the heat conducted to the primary electrode side glaze glass 52. And the heat conducted to the secondary electrode side glaze glass 62 prevents mutual thermal interference. The groove 43 is formed on the substrate 41.
Is thermally divided into two parts, that is, a primary electrode side substrate part 41a.
And the secondary electrode side substrate portion 41b. Groove 43
Since the thermal resistance between the separation regions changes depending on the thickness J of the substrate at the upper end of the substrate, the thickness J is set to the thickness of the thermal resistance that does not cause thermal interference, thereby minimizing mutual heat inflow and outflow. And can be separated into two parts as described above.

The distance L between the heating resistor 14 and the end of the projection 42 (or the distance between the heating resistor 24 and the end of the projection 42) L and the thickness P of the glaze glass layer 62b. Accordingly, the thermal resistance between the heating resistor 14 and the end of the projection 42 (or the thermal resistance between the heating resistor 24 and the end of the projection 42) changes. Therefore, the dimensions of the distance L and the thickness P need to be adjusted to be short in order to improve the rapid thermal response, that is, the heat radiation characteristic in the case of high-speed printing or high-gradation printing. However, the glaze glass layer 62b, 1
The secondary electrode-side partial glaze glass 52 and the secondary electrode-side partial glaze glass 62 are insulating films that electrically insulate the resistors 11 and 21 from the substrate 41 (including the protrusions 42), and thus have a thickness T. Must have a thickness that satisfies electrical insulation. The dimension of the normal distance L is, in the case of the substrate 41 described above,
The range is from several μm to several mm.

In the above-described thermal head according to the first embodiment of the present invention, the electrode-side substrate portion 41 is radiated from the primary-electrode-side glaze glass 52 by the above-described groove portion 43.
a and the heat accumulated in the secondary-electrode-side substrate portion 41b due to the heat radiation from the secondary-electrode-side glaze glass 62 can prevent mutual interference. Independent heat control of the heating resistor 14 and the secondary electrode substrate 41b can be performed. Further, the thermal head according to the first embodiment of the present invention has two rows of heating resistors arranged in the main scanning direction, so that two different lines can be simultaneously printed, and the printing speed is a single line. As compared with the thermal head, there is an effect that the printing speed can be improved and the printing time for one printing sheet can be reduced.

Further, in the thermal head according to the first embodiment of the present invention, the primary electrode side partial glaze projection 52a is provided below the heating resistor 14, and the secondary electrode side portion is provided below the heating resistor 24. Since the glaze protrusion 62a is provided, each of the heat generating resistors 14, 24 protrudes upward, so that the Joule heat generated by the heat generating resistors 14, 24 can be efficiently transmitted to the printing paper, and a high joule heat can be obtained. Since printing can be performed without generating heat, the amount of heat transmitted to the primary electrode-side glaze glass 52 and the secondary electrode-side glaze glass 62 can also be reduced, and heat radiation characteristics can be improved. In addition, the thermal head according to the first embodiment of the present invention includes the primary electrode side glaze glass 52.
A projection 42 is formed between the glaze glass 62 and the secondary electrode side, and in order to electrically insulate the projection 62 and the resistors 11 and 22, the glaze glass layer 62 b is
The glaze glass layer 62b is formed on two surfaces, and the glaze glass layer 62b is thinner than the primary electrode side glaze glass 52 and the secondary electrode side glaze glass 62.
The amount of heat absorbed by the protrusions 42 is larger than the amount of heat transmitted through the conductive member 2b, and the heating resistor 14 and the heating resistor 2
4 is suppressed.

<Second Embodiment> FIG. 2 shows a second embodiment of the present invention.
1 shows a configuration of a dot shift type thermal head according to the embodiment. Note that FIG. 2A is a top view and is configured to be line-symmetric with respect to a center line QQ ′. FIG. 2B is a line EE ′ in FIG.
FIG. The configuration of the second thermal head is the same as that of the first embodiment, and the same components are denoted by the same reference numerals and description thereof will be omitted. The difference between the thermal head of the second embodiment and the thermal head of the first embodiment is that the heating resistors 14 and 24 are formed with a shift of 1/2 pitch in the main scanning direction. It is.

Therefore, the thermal head according to the second embodiment can obtain the same effect as the first thermal head. However, in contrast to the effect of improving the printing speed in the first embodiment, the thermal head of the second embodiment uses the heating resistor 14 and the heating resistor 14 that are displaced in the main scanning direction by ず つ pitch at a time. By performing printing processing on the same line with the body 24, it is possible to easily and inexpensively obtain twice the printing density without using a fine process of reducing the pitch of the heating resistors by half. There is an effect that can be.

<Third Embodiment> FIG. 3 shows a third embodiment of the present invention.
1 shows a configuration of a type of thermal head most suitable for full-color direct thermal paper according to the embodiment. Note that FIG. 3A is a top view and is configured to be line-symmetric with respect to a center line QQ ′. FIG. 3B is a sectional view taken along line FF ′ in FIG. 3A. This third
The configuration of the thermal head is the same as that of the first embodiment, and the same components are denoted by the same reference numerals and description thereof will be omitted. The thermal head of the third embodiment is
The difference from the thermal head of the embodiment is that the heating resistor 24 of the secondary electrode side substrate portion 41a is formed as a heating resistor for preheating.

Therefore, the control IC 29 does not exist, but the collective electrode 29 is provided instead, and the individual lead electrode 27a is connected. Then, this collective electrode 2
An electric current is caused to flow through the heating resistor 24 via the heat generating element 9 to generate Joule heat, and the Joule heat preheats the ink ribbon and the thermal paper. That is, the heat value of the Joule heat is slightly smaller than the boundary at which the thermal transfer and the heat-sensitive coloring of the sublimation dyes corresponding to the respective colors of Y (yellow), M (magenta) and C (cyan) are started, that is, the threshold value. Set to low. Therefore, in this preheating process, there is no printing on the printing paper or coloring of the thermal paper. At this time, the printing paper is conveyed from the heating resistor 24 to the heating resistor 14 by a paper feeding device (not shown).

Then, the place preheated by the heating resistor 24 of the ink ribbon and printing paper or thermal paper is transported to the position of the heating resistor 14 and
Generates heat in accordance with the current flowing when the transistors in the control IC 19 are turned on / off based on data (data indicating the gradation) supplied from a control device (not shown), and reduces the amount of generated Joule heat. Supply to the preheated place. Thereby, the amount of heat supplied from the heating resistor 14 (the amount of heat corresponding to the gradient) and
Due to the sum of the amount of heat generated by the preheating and the heat transfer of the sublimation dye of the ink ribbon or the heat-sensitive coloring, printing is performed on the printing paper at a predetermined gradation.

As described above, the thermal head according to the third embodiment has the same configuration as that of the first thermal head, so that the same effects can be obtained. However, in contrast to the effect of improving the printing speed by simultaneously printing two lines in the first embodiment, the thermal head of the second embodiment has a two-line heating resistor functioning both for preheating and for printing. Since the preheating and printing processes can be performed simultaneously, the conventional thermal head, which has only one line of heating resistor, uses the same heating resistor for preheating and printing. The printing time can be greatly shortened, while the printing is performed separately. In the thermal head according to the second embodiment, the heating resistors are divided into functions for preheating and for printing. Therefore, one line corresponds to one heating resistor in one heating resistor.
Since each heating resistor generates heat according to its function as compared with the case where the printing process is performed by heat generation each time, the current flowing through each heating resistor can be reduced, and the heating resistors (14, 24), it is not necessary to supply a large current in a short time, and the stress based on the thermal stress generated due to the difference in the thermal expansion coefficient between the substrate and the common electrode as in the conventional example shown in FIG. 5 can be reduced. This has the effect of preventing the heat generation characteristics of the head from deteriorating.

<Fourth Embodiment> In a fourth embodiment, a filling groove is formed on the back surface of the substrate 41 in the first, second, and third embodiments, and the primary electrode side partial glaze glass 52,
Glass of the same material as the secondary electrode side partial glaze glass 62 is filled. That is, in the production of the thermal head, a glass paste of a glaze glass material is applied to the surface of the substrate 41 by screen printing, and the glass paste is filled in a filling groove formed on the back surface of the substrate 41, and baked. Primary electrode side partial glaze glass 52 and secondary electrode side partial glaze glass 6
Form 2

As a result, the warpage of the substrate 41 due to the thermal stress generated due to the difference in the linear expansion coefficient between the glaze glass and the substrate 41 reduces the primary electrode side partial glaze glass 5 on the substrate surface.
2. The secondary electrode side partial glaze glass 62 and the glass of the filling groove on the back face cancel each other to reduce the warpage of the substrate 41, and the primary electrode side partial glaze glass 52 due to stress.
Further, the peeling of the secondary electrode side partial glaze glass 62 from the substrate 41 is reduced. In the configuration of FIG.
3 is used as the filling groove, and the inside of the groove portion 43 is filled with glass 100.

In the configuration of FIG. 5, a filling groove 101 is formed near the formation of the primary electrode side partial glaze glass 52 and the secondary electrode side partial glaze glass 62 in addition to the groove 43. Glass 10 inside filling groove 101
2 is filled. The filling groove 101 is formed by etching and laser processing. As shown in FIGS. 4 and 5, in order to effectively prevent the warpage due to the difference in thermal expansion coefficient, the primary electrode side partial glaze glass 52 and the secondary electrode side partial glaze glass 62 are formed. It is necessary to form a filling groove in the vicinity. In addition, since the surface of the glass filled in the filling groove with respect to the opening portion needs to be inside the substrate with respect to the back surface in consideration of attachment of a radiation fin, etc. Should not be filled.

As described above, the fourth embodiment is different from the one shown in FIG.
By using the configuration of FIG. 5 in the first to third embodiments, in addition to the effects of each embodiment, a filling groove is formed on the back surface of the substrate 41, and the glass paste applied to the surface is By filling the filling grooves and forming the partial glaze glass by firing, the thermal stresses are canceled out, the warpage due to the thermal stress of the substrate 41 is reduced, and the peeling of each glaze glass from the substrate 41 due to the stress due to the warpage is prevented. This can improve the production yield of the thermal head.

<Fifth Embodiment> In the fifth embodiment, the substrate 41 of the first to third embodiments is changed to, for example, an alumina substrate 71, and the substrate of the thermal head during firing of the partial glaze glass is changed. The warpage is reduced, and peeling of the primary electrode side partial glaze glass 52 and the secondary electrode side partial glaze glass 62 from the alumina substrate 71 of the thermal head is prevented. That is, by using a substrate made of a material having a thermal expansion coefficient close to that of the partial glaze glass of the primary electrode side partial glaze glass 52 and the secondary electrode side partial glaze glass 62, that is, an alumina substrate 71, generation of thermal stress itself is prevented. And significantly reduce the warpage of the substrate.

The manufacture of the alumina substrate 71 is performed, for example, by the following process. A green sheet for the alumina substrate 71 is formed in a size corresponding to the substrate of the thermal head. The protrusions 42 (fine protrusions) and the grooves 43 (fine processing grooves) are formed on the green sheet using a spatula, rollers, dedicated jigs, and the like. The green sheet subjected to the fine processing is heated at the firing temperature of alumina, and the alumina substrate 71 is fired. In order to form the primary electrode side partial glaze glass 52 and the secondary electrode side partial glaze glass 62, a glass paste of the above-mentioned partial glaze glass material is screen-printed on the protrusion 42. The primary electrode side partial glaze glass 52 and the secondary electrode side partial glaze glass 62 are formed according to the firing temperature of the glaze glass. After that, the heating resistors 14 and 24 are formed. As described above, the alumina substrate 71 has a structure in which fine projections are easily formed, has a coefficient of thermal expansion similar to that of glaze glass, has low thermal distortion, can be integrated by firing with glaze glass, and has a surface Can be prevented from being peeled off.

As described above, the fifth embodiment is similar to the first embodiment.
-By using the alumina substrate 71 as the substrate of the thermal head according to the third embodiment, in addition to the effects of each embodiment, since the linear expansion coefficient between alumina and the material of the partial glaze glass is close, When forming by baking, it is difficult to generate thermal stress itself, reducing the warpage of the thermal head, preventing the peeling of each glaze glass from the substrate of the thermal head due to the stress due to the warping, and manufacturing the thermal head The yield can be improved.

The embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention includes not only the above-described embodiments but also designs and modifications that do not depart from the gist of the present invention. included. For example, in the first to third embodiments, the folded portions of the resistor 11 and the resistor 21 are:
As shown in FIG. 6 (a), the intermediate electrode 15 (or 25) is formed on the folded portion, but the intermediate electrode 15 is not provided. The structure may be the body 14 (or 24).

FIG. 6A shows the folded portion in FIG.
It may be formed in a bent shape as shown in FIG. In other words, in the area of the folded portion where heat is generated, a path through which current flows and generates heat is bent to increase the density of the heat generating portion and make heat supply uniform, thereby realizing a more accurate gradation. It becomes possible. Therefore, it is necessary to make a single heating resistor as thin as possible in a predetermined area where heat generation is required, and to bend it to make the heat distribution in the heat generation area uniform.

[0038]

According to the thermal head of the present invention, the heat stored in the substrate on the first heating resistor side by the heat dissipation from the first insulator and the heat generated from the second insulator by the groove are increased. The heat radiation can prevent mutual interference with heat accumulated in the electrode-side substrate portion on the second heating resistor side, and independent heat control of the first heating resistor and the second heating resistor can be achieved. Can be performed. According to the thermal head of the present invention, the first insulator is provided below the first heating resistor, and the second insulator is provided below the second heating resistor. The first and second heating resistors protrude upward, so that the Joule heat generated by the first and second heating resistors can be efficiently transmitted to the printing paper without generating high Joule heat. Since printing can be performed, the amount of heat transmitted to the first insulator and the second insulator can also be reduced, and heat radiation characteristics can be improved. Oh,
According to the thermal head of the present invention, a projection is formed between the first insulator and the second insulator, and the glaze glass layer is projected to electrically insulate the projection from the resistor. Since the glaze glass layer is thinner than the thicknesses of the first insulator and the second insulator, the glaze glass layer is absorbed by the protrusions rather than the heat transmitted through the glaze glass layer. The amount of heat generated is larger, and there is an effect that thermal interference between the first heating resistor and the second heating resistor is suppressed.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a structure of a thermal head according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a structure of a thermal head according to a second embodiment of the present invention.

FIG. 3 is a conceptual diagram showing a structure of a thermal head according to a third embodiment of the present invention.

FIG. 4 is a conceptual diagram illustrating a structure of a thermal head according to a fourth embodiment of the present invention.

FIG. 5 is a conceptual diagram illustrating a structure of a thermal head according to a fourth embodiment of the present invention.

FIG. 6 is a conceptual diagram showing the shape of a heating resistor according to the present invention.

FIG. 7 is a conceptual diagram showing a structure of a thermal head according to a conventional example.

FIG. 8 is a conceptual diagram showing a structure of a thermal head according to a conventional example.

FIG. 9 is a conceptual diagram showing a structure of a thermal head according to a conventional example.

FIG. 10 is a conceptual diagram showing a structure of a thermal head according to a conventional example.

[Explanation of symbols]

11, 21 Resistor 14, 24, 13a, 13b, 23a, 23b Heating resistor 15 Intermediate electrode 17a, 17b, 27a, 27b Individual lead electrode 18, 28 Bonding wire 19, 29 Control IC 41 Substrate 41a Primary electrode side substrate Part 41a 41b Secondary electrode side substrate part 41b 42 Projection part 43 Groove part 52 Primary electrode side partial glaze glass 52a Primary electrode side partial glaze projection 62 Secondary electrode side partial glaze glass 62a Secondary electrode side partial glaze projection 62b Glaze glass Layer 71 Alumina substrate 100, 102 Glass 101 Filling groove

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Takashi Kubota 100, Takegahana-cho, Ise-shi, Mie Prefecture Inside Shinko Electric Co., Ltd. (72) Inventor Kazunori Masukawa 100 Takegahana-cho, Ise-shi, Mie Shinko Electric F-term in Ise Seisakusho, Ltd.

Claims (6)

[Claims] A substrate having an elongated projection formed in the main scanning direction; a plurality of first heating resistors arranged on one side of the projection in the main scanning direction; A plurality of second heating resistors arranged on the other side in the main scanning direction, a first insulator interposed between the first heating resistor and the substrate, And a second insulator interposed between the heating resistor and the substrate, wherein a groove is formed along the protrusion on the back surface of the substrate. 2. The semiconductor device according to claim 1, wherein the substrate is thermally separated by the groove corresponding to a region of the first heating resistor and a region of the second heating resistor. Thermal head. 3. The thermal head according to claim 1, wherein the substrate is formed using a material having a thermal expansion coefficient close to that of the first and second insulators. 4. A filling groove is formed on the back surface of the substrate, and the filling groove is filled with an insulator of the same material as the first and second insulators. Item 4. The thermal head according to item 2. 5. The projection according to claim 1, wherein the first and second heating resistors absorb heat radiated to the first insulator and the second insulator, respectively, and radiate the heat to the substrate. The thermal head according to claim 1. 6. The apparatus according to claim 1, wherein the first heating resistor and the second heating resistor are formed so as to be shifted from each other by ピ ッ チ pitch in the main scanning direction. A thermal head according to claim 5.