JP2009119851A - Heating resistor element, manufacturing method for the same, thermal head, and printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve printing quality while suppressing heat accumulation in a gas of a hollow portion. <P>SOLUTION: The heating resistor element 1 includes: an insulating substrate 9; a heat accumulating layer 10 bonded to a surface of the insulating substrate 9; and a heating resistor 11 provided on the heat accumulating layer 10, in which: on a bonded surface 9a between the insulating substrate 9 and the heat accumulating layer 10, at least one of the insulating substrate 9 and the heat accumulating layer 10 is provided with a concave portion 16 in a region opposed to the heating resistor 11 to form a hollow portion 17; and the hollow portion 17 includes an inner surface on a side of the insulating substrate 9, the inner surface being processed to have surface roughness Ra of 0.2 μm or more. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heating resistor element, a manufacturing method thereof, a thermal head, and a printer.

  2. Description of the Related Art Conventionally, a heating resistor element provided in a thermal head of a printer has a cavity formed in a region facing the heating resistor in order to improve the heating efficiency of the heating resistor and reduce power consumption. The amount of heat flowing from the heating resistor to the insulating substrate is limited by causing the portion to function as a heat insulating layer having a low thermal conductivity (see, for example, Patent Document 1).

  As a method for forming the cavity, a silicon substrate is etched or laser processed to form a recess (depth 1 μm or more and 100 μm or less), and a thin glass (10 to 100 μm) as a heat storage layer is formed thereon 700 Bonding by anodic bonding at a temperature of ℃ or less is employed. In this case, since it is difficult to manufacture and handle a thin glass having a thickness of 100 μm or less, after a thin glass having a relatively easy thickness is bonded to the surface of the silicon substrate, the surface opposite to the bonding surface is etched or polished. The desired thickness dimension was obtained by scraping.

  In this case, most of the heat generated from the heating resistor is restricted from flowing to the insulating substrate side by the cavity that is a heat insulating layer, and is efficiently used as heat for printing. On the other hand, part of the heat not used for printing is transferred from the heating resistor to the gas in the cavity through the heat storage layer in contact with the heat resistor, and further transferred from the gas in the cavity to the insulating substrate. .

JP 2007-83532 A

  However, in the conventional heating resistor element, since the cavity is formed by etching or laser processing, the surface on the insulating substrate side of the inner surface of the cavity is formed very smoothly. Is difficult to be transmitted to the insulating substrate side. That is, heat transfer from the gas in the cavity to the insulating substrate is performed when the gas molecules collide with the insulating substrate, but if the surface of the insulating substrate is smooth, the gas molecules that collide with the insulating substrate per unit time. The number of For this reason, the heat transferred to the gas is difficult to escape to the insulating substrate side and is stored in the gas.When printing is performed for a long time, the cavity becomes a heat source, and the print continues in the paper feed direction. There is a problem that the print quality deteriorates, such as a drawing phenomenon.

  The present invention has been made in view of the above-described circumstances, and provides a heating resistor element, a manufacturing method thereof, a thermal head, and a printer that can suppress heat accumulation in a gas in a cavity and improve printing quality. The purpose is that.

In order to achieve the above object, the present invention provides the following means.
The present invention comprises an insulating substrate, a heat storage layer bonded to the surface of the insulating substrate, and a heating resistor provided on the heat storage layer, and a bonding surface between the insulating substrate and the heat storage layer, In the region facing the heating resistor, a cavity is formed by providing a recess in at least one of the insulating substrate or the heat storage layer, and the inner surface of the cavity on the insulating substrate side has a surface roughness Ra of 0.2 μm or more. A heating resistor element being processed is provided.

According to the present invention, the insulating substrate in which the concave portion is formed on at least one of the joining surfaces and the heat storage layer are bonded to each other, and the cavity formed between the insulating substrate and the heat storage layer becomes the heating resistor. Since they are formed in the opposing regions, the conduction of heat generated from the heating resistor to the insulating substrate side is limited by the cavity, and can be used more efficiently.
In this case, since the inner surface of the cavity on the insulating substrate side is processed to have a surface roughness Ra of 0.2 μm or more, the surface area is enlarged compared to the inner surface of the recess formed smoothly by etching or the like. The chance that the gas molecules sealed in the cavity collide with the insulating substrate can be increased. As a result, the heat transferred to the gas can be quickly transferred to the insulating substrate to dissipate heat, and the inconvenience that is stored in the cavity can be prevented.

In the above invention, the depth of the hollow portion may be not less than 1 μm and not more than 100 μm.
By doing in this way, the thickness of the gas in a cavity part is fully ensured with 1 micrometer or more, the heat insulation effect is high, and the power consumption of a heating resistive element can be restrained low. In addition, by setting the depth of the cavity to 100 μm or less, the thickness of the heating resistor element can be reduced.

Moreover, in the said invention, the said insulated substrate and the said thermal storage layer may be comprised with the alkali free glass.
By doing in this way, even if it uses for a long time, an alkali ion does not elute. Therefore, it is possible to prevent adverse effects due to alkali ions on the surrounding heating resistors, electrodes, or driver ICs installed in the vicinity thereof.
Further, alkali-free glass is less expensive than Pyrex (registered trademark) glass and has good workability, so that a heating resistor element can be manufactured at low cost.

In the above invention, the insulating substrate and the heat storage layer are bonded by heating to a temperature between the annealing point and the softening point in a state where the bonding surfaces of the two are in close contact with each other. May be.
In this way, even if the insulating substrate and the heat storage layer are made of the same glass material, the insulating substrate and the heat storage layer can be easily bonded together, eliminating the difference in thermal expansion coefficient between the insulating substrate and the heat storage layer, Generation of distortion can be suppressed.

Moreover, in the said invention, the said cavity part may be sealed with respect to the exterior and gas may be enclosed with the inside.
By doing in this way, the pressing force applied to the heating resistor can be supported by the pressure of the gas sealed in the cavity, and a heating resistor element with high pressure resistance can be provided.

Moreover, in the said invention, it is preferable that the said gas is an inert gas.
By doing in this way, deterioration, such as oxidation of a heating resistor, can be prevented and reliability and durability can be improved.

Moreover, this invention provides a thermal head provided with one of the said heating resistance elements.
According to the present invention, it is possible to prevent the inconvenience that the hollow portion becomes a heat source even if it is used for a long time, and to prevent the deterioration of print quality due to a phenomenon such as tailing.

Moreover, this invention provides a printer provided with the said thermal head.
According to the present invention, clear printing can be continuously performed for a long time at low cost.

  Further, the present invention provides a recess forming step for forming a recess in at least one of the bonding surfaces of the insulating substrate and the heat storage layer, and a bonding step for bonding the bonding surfaces of the insulating substrate and the heat storage layer to each other. A resistor forming step of forming a heating resistor at a position facing the recess on the heat storage layer, and the recess forming step has a surface roughness Ra of 0.2 μm on the inner surface of the recess on the insulating substrate side. Provided is a method for manufacturing a heating resistor element to be processed as described above.

  According to the present invention, in the recess forming step, the surface roughness of the inner surface of the recess on the insulating substrate side is processed to Ra of 0.2 μm or more, so that the cavity formed by joining the insulating substrate and the heat storage layer A heating resistor element can be manufactured in which the surface on the insulating substrate side is formed sufficiently rougher than when the surface is formed smoothly by etching or the like. As a result, it increases the chance of contact of gas molecules in the cavity with the insulating substrate, promotes more active heat dissipation from the gas to the insulating substrate, and causes the disadvantage that the cavity becomes a heat source even after long-term use. Can be prevented in advance.

In the said invention, the said recessed part formation step is good also as forming a recessed part by sandblasting. Moreover, the said recessed part formation step is good also as forming a recessed part by the high temperature press molding using a metal mold | die.
By doing so, it is possible to easily form a concave portion that has a radius of curvature of 10 μm or more at each corner and is sufficiently rough as compared with the case where the inner surface is formed smoothly by etching or the like by sandblasting or high-temperature pressure molding. Can be formed. As a result, in addition to the above effects, the chance of contact of the gas molecules in the cavity formed by closing the recess with the insulating substrate is increased, and more active heat dissipation from the gas to the insulating substrate is achieved. It is possible to easily manufacture a heating resistor element that does not cause the inconvenience that the cavity becomes a heat source even after long-term use.

  According to the present invention, it is possible to suppress the heat accumulation in the gas in the cavity and improve the printing quality.

A heating resistor element 1 and a manufacturing method thereof, a thermal head 2 and a thermal printer (printer) 3 according to an embodiment of the present invention will be described below with reference to FIGS.
The heating resistor element 1 according to the present embodiment is used in the thermal head 2 of the thermal printer 3 shown in FIG.

  The thermal printer 3 includes a main body frame 4, a horizontally placed platen roller 5, a thermal head 2 arranged to face the outer peripheral surface of the platen roller 5, and a thermal paper 6 between the platen roller 5 and the thermal head 2. And a pressurizing mechanism 8 that presses the thermal head 2 against the thermal paper 6 with a predetermined pressing force.

The thermal head 2 is formed in a flat plate shape as shown in the front view of FIG. 2, and includes a plurality of heating resistor elements 1 at intervals. As shown in the longitudinal sectional view of FIG. 3, each heating resistance element 1 includes an insulating substrate 9, a heat storage layer 10, a heating resistor 11, and a protective film layer 12 in a laminated state.
Although not shown, the insulating substrate 9 is bonded to the heat sink.

The insulating substrate 9 and the heat storage layer 10 are both made of non-alkali glass (Corning 1737), and in a state where they are in close contact with each other, the annealing point (720 ° C.) to the softening point (975 ° C.) Are joined to each other by heating to a temperature of up to.
The heat storage layer 10 is configured to have a thickness of 2 μm to 100 μm.

The heating resistor 11 has a heating resistor layer 13 formed in a predetermined pattern on the heat storage layer 10, and an individual electrode 14 and a common electrode 15 provided on the heat storage layer 10 in contact with the heating resistor layer 13. is doing.
A recess 16 is formed in a region facing each heating resistor 11 on at least one of the bonding surfaces of the insulating substrate 9 and the heat storage layer 10 (the bonding surface 9a of the insulating substrate 9 in this embodiment). When the insulating substrate 9 and the heat storage layer 10 are bonded in close contact, the opening of the recess 16 is blocked by the flat surface of the heat storage layer 10, thereby generating heat between the insulating substrate 9 and the heat storage layer 10. A sealed cavity 17 is provided at a position facing the resistor 11.

Here, the shape of the recess 16 is arbitrary, and the size thereof may be larger or smaller than the heating resistor 11 as long as it is close to the dimension of the heating resistor 11.
When the concave portion 16 is viewed from the side of the heating resistor 11 in the stacking direction, the heat insulating performance between the heating resistor 11 and the insulating substrate 9 is improved when it is larger than the effective heat generation area of the heating resistor 11. be able to. On the other hand, when the size of the recess 16 is made smaller than the effective heating area of the heating resistor 11, the mechanical strength of the heating resistor element 1 against the pressing force in the stacking direction can be improved.

  In the present embodiment, the recess 16 is provided on the insulating substrate 9 side, and is formed in a substantially similar quadrangle that is slightly larger than the heating resistor 11 when viewed in the stacking direction from the heating resistor 11 side. . The depth D of the recess 16 is set to 1 μm or more and 100 μm or less. That is, in this heat generating resistive element 1, the thickness of the gas layer in the cavity 17 is sufficiently secured to be 1 μm or more, and the heat insulating effect by this gas layer is high. In addition, by setting the depth D of the recess 16 to 100 μm or less, the thickness dimension of the heating resistor element 1 can be sufficiently reduced.

  Further, in the present embodiment, as shown in FIG. 4, each corner R1, R2, R3 of the recess 16 is formed in a shape having a radius of curvature of 10 μm or more. The inner surface of the recess 16 is formed to have a surface roughness Ra of 0.2 μm or more. 4A is a front view of the recess 16 as viewed from the opening side, and FIGS. 4B and 4C are respectively aa longitudinal sectional view and bb longitudinal sectional view.

In addition, there exists the following relationship between the opening part dimension W and L of the recessed part 16, and the curvature radius R1, R2, R3 of each corner | angular part. That is, 10 μm ≦ R1 ≦ 1 / 2L, 10 μm ≦ R2 ≦ 1 / 2W,
0 μm ≦ R3 ≦ 1 / 2L (when L ≦ W) or 10 μm ≦ R3 ≦ 1 / 2W (when W ≦ L).

Next, a method for manufacturing the heating resistor element 1 and the thermal head 2 according to the present embodiment will be described.
First, a recess 16 having a predetermined depth is formed in a region where the heating resistor 11 is formed on one surface of the insulating substrate 9 (a recess forming step).

  As shown in FIG. 5, the recess 16 is formed by applying a photoresist material 18 capable of absorbing shock, such as urethane, to one surface of an alkali-free glass substrate constituting the insulating substrate 9 (b) ) The photoresist material 18 is exposed using a photomask (not shown) having a predetermined pattern, the portion other than the region where the cavity 17 is formed is solidified, and the unsolidified region is removed, thereby removing the window portion 19. Form. In this state, (c) sandblasting is performed to scrape the insulating substrate 9 corresponding to the window portion 19 with sand. Thereby, the recessed part 16 which has a curvature radius of 10 micrometers or more in a corner | angular part, and has the inner surface of surface roughness Ra0.2micrometer or more can be formed easily.

  The radius of curvature and surface roughness of the corners can be adjusted to desired values by appropriately adjusting the mask shape, sand particle diameter, blast pressure, sand particle amount and spray angle. When the surface roughness is less than Ra 0.2 μm, it is necessary to make the sand particle diameter very small, and the amount of processing (removed amount) per unit time is considerably reduced. In this state, (d) the photoresist material 18 is removed from the surface of the insulating substrate 9. Instead of sandblasting, the recess 16 may be formed by high temperature molding using a mold.

Next, an alkali-free glass substrate to be the heat storage layer 10 is prepared, and (e) the concave portion 16 is closed by being in close contact with the surface 9a of the insulating substrate 9 on which the concave portion 16 is formed. In this state, the insulating substrate 9 and the heat storage layer 10 are heated to a temperature between the annealing point of non-alkali glass (720 ° C.) and the softening point (975 ° C.) to join them together (bonding step).
Thereafter, (f) the surface opposite to the bonding surface of the heat storage layer 10 is removed by etching or polishing, and the heat storage layer 10 is processed into a desired thickness dimension (2 μm to 100 μm).

  Then, the heating resistor layer 13, the individual electrode 14, the common electrode 15, and the protective film layer 12 are sequentially formed (resistor forming step). The order in which the heating resistor layer 13, the individual electrode 14, the common electrode 15 and the protective film layer 12 are formed may be arbitrary.

The heating resistor layer 13, the individual electrode 14, the common electrode 15 and the protective film layer 12 can be formed using a method for manufacturing these members in a conventional heating resistor element.
Specifically, a thin film of a material of the heating resistor layer 13 such as a Ta-based or silicide-based film is formed on the heat storage layer 10 by using a thin film forming method such as sputtering, CVD (chemical vapor deposition), or vapor deposition. The heating resistor layer 13 having a desired shape is formed by forming a thin film of the material of the heating resistor layer 13 using a lift-off method, an etching method, or the like.

  Similarly, a wiring material such as Al, Al-Si, Au, Ag, Cu, Pg or the like is formed on the heat storage layer 10 by sputtering or vapor deposition, and this film is formed by using a lift-off method or etching method. The individual electrode 14 and the common electrode 15 having a desired shape are formed by, for example, firing the wiring material after screen printing.

In the present embodiment, two independent individual electrodes 14 are provided for one heating resistor layer 13, and the common electrode 15 is provided on one individual electrode 14, so that the wiring resistance value of the common electrode 15 can be reduced. We are trying to reduce it.
Then, after forming the heating resistor layer 13, the individual electrode 14, and the common electrode 15, the material of the protective film layer 12 such as SiO2, Ta2O5, SiAlON, Si3N4, diamond-like carbon, etc. is sputtered or ion-plated on the heat storage layer 10. Then, the protective film layer 12 is formed by film formation by a CVD method or the like. Thereby, a thermal head 2 including a plurality of heating resistance elements 1 according to this embodiment is manufactured.

  According to the heating resistor element 1 and the thermal head 2 according to the present embodiment configured as described above, the cavity portion 17 is formed in a region facing the heating resistor 11 between the insulating substrate 9 and the heat storage layer 10. Thus, the gas layer in the hollow portion 17 functions as a heat insulating layer that restricts the inflow of heat from the heat storage layer 10 to the insulating substrate 9. In the present embodiment, since the depth D of the recess 16 is 1 μm or more, a sufficiently thick gas layer is formed, and a high heat insulating effect is achieved.

Furthermore, since the thickness of the heat storage layer 10 is set to 100 μm or less, the heat capacity of the heat storage layer 10 itself is small, and the heat generated by the heating resistor 11 is suppressed from being taken away by the heat storage layer 10.
Thus, in the heat generating resistive element 1 and the thermal head 2 according to the present embodiment, the heat generated from the heat generating resistor 11 can be effectively used without releasing it to the heat storage layer 10 side. Therefore, the heat generation efficiency of the heat generating resistor 11 can be improved and the power consumption can be reduced.

Further, since the heat generated from the heating resistor 11 is not easily transmitted to the insulating substrate 9, there is an advantage that the temperature of the entire thermal head 2 is not easily raised even if it is continuously used.
Furthermore, in the heating resistor element 1 according to the present embodiment, since the heat storage layer 10 and the insulating substrate 9 are made of the same glass material, there is no difference in thermal expansion coefficient, and the heat generated from the heating resistor 11 There is no inconvenience of warping or distortion.

Further, in the heating resistor element 1 according to the present embodiment, the heat storage layer 10 and the insulating substrate 9 are made of non-alkali glass, so that alkali ions do not elute even when used for a long time. Therefore, it is possible to prevent adverse effects due to alkali ions on the surrounding heating resistor 11, the electrodes 14, 15 or the driver IC installed in the vicinity thereof.
In addition, since the alkali-free glass is cheaper than Pyrex (registered trademark) glass and has good workability, the heating resistor element 1 can be manufactured at a low cost.

  In addition, the thermal conductivity of silicon is 168 W / mK, whereas the thermal conductivity of glass is 0.9 W / mK, and the thermal conductivity of air is 0.02 W / mK, replacing the conventional silicon substrate. By employing an alkali-free glass substrate, it is possible to sufficiently reduce the thermal conductivity and prevent heat from being radiated from the heat storage layer 10 through the insulating substrate 9, thereby further improving the thermal efficiency.

  Moreover, since the surface roughness of the inner surface of the concave portion 16 forming the cavity portion 17 is set to Ra 0.2 μm or more, the heating resistor element 1 according to the present embodiment is formed smoothly by etching or the like. The surface area is enlarged as compared with the inner surface of the recess, and the chance that the gas molecules sealed in the cavity 17 collide with the insulating substrate 9 can be increased.

For example, FIG. 6 shows the thermal response characteristics of the heating resistor element 1 for each surface roughness of the recess 16. In FIG. 6, graphs t <b> 1 and t <b> 2 indicate changes in the temperature of the thermal head 2 when a voltage is applied to the thermal head 2 for a predetermined time and then rests for a predetermined time. Graphs t3 and t4 are virtual curves connecting the temperatures of the thermal head 2 before voltage is applied, and are also shown for easy understanding of the thermal head 2 of the present invention.
FIG. 6A is a graph showing a comparison between the thermal response characteristics in the case of the conventional surface roughness (Ra 0.02 μm) and the minimum surface roughness (Ra 0.2 μm) of the present embodiment, (b ) Is a graph showing a comparison between the thermal response characteristics in the case of the conventional surface roughness (Ra 0.02 μm) and the maximum surface roughness (Ra 3 μm) of the present embodiment. According to this, according to this embodiment, it turns out that the temperature rise by long-time use is suppressed lower than before.

FIG. 7 shows the relationship between the temperature of the heating resistor element 1 after 10 pulses of repeated heat generation (after 0.025 seconds) and the surface roughness of the inner surface of the cavity 17 as shown in FIG. Show.
According to these graphs, the heat transfer element 1 according to the present embodiment can quickly transfer the heat transferred to the gas layer to the insulating substrate 9 for heat dissipation.

  In addition, since the heating element 1 according to the present embodiment is configured to have a rounded shape in which the corners R1 to R3 of the recess 16 forming the cavity 17 have a radius of curvature of 10 μm or more. Stress concentration in the portions R1 to R3 is suppressed, and the mechanical strength can be improved. Moreover, since mechanical strength is high, even if the thickness of the heat storage layer 10 is 2 to 100 μm, it is possible to provide the heating resistor element 1 having sufficient mechanical strength. By making the heat storage layer 10 thinner, the heat generation efficiency can be further improved.

  Therefore, according to the thermal printer 3 including the thermal head 2 according to the present embodiment, even when the thermal printer 3 is used for a long time, the heat from the heating resistor 11 is not easily stored in the heat storage layer 10 or the cavity portion 17. It can be used efficiently, and the cavity 17 can be prevented from becoming a heat source. As a result, it is possible to prevent a decrease in print quality due to a phenomenon such as tailing. Further, since the warp or distortion due to the difference in thermal expansion coefficient does not occur in the thermal head 2, no change in the contact between the thermal head 2 and the thermal paper 6 occurs, and it is possible to prevent deterioration in print quality.

Furthermore, the thermal strength of the thermal head 2 is high, and the thermal head 2 can be maintained in a healthy state even when a pressing force is applied repeatedly for a long time.
Therefore, it is possible to provide a highly efficient heating resistor element 1, thermal head 2, and thermal printer 3 that ensure long-term reliability.

  Moreover, according to the manufacturing method of the heating resistor element 1 according to the present embodiment, the heat storage layer 10 and the insulating substrate 9 made of the same alkali-free glass are heated to a temperature between the annealing point and the softening point of the alkali-free glass. Therefore, the adhesive layer is not required, the material of the adhesive layer and the step of forming the adhesive layer are unnecessary, and the heating resistor element 1 can be easily manufactured at low cost and in a short time. .

  In the heating resistor element 1 according to the present embodiment, the insulating substrate 9 and the heat storage layer 10 are made of the same alkali-free glass. However, the invention is not limited to this, and the same soda glass material or the same Pyrex (registered trademark) glass material may be used. In the case of soda glass, the temperature between the annealing point (540 ° C.) and the softening point (730 ° C.), and in the case of Pyrex (registered trademark) glass, the annealing point (565 ° C.) to the softening point (820 ° C.). If it is heated to a temperature between), it can be similarly easily joined.

  Moreover, in this embodiment, the recessed part 16 provided in the insulated substrate 9 was obstruct | occluded with the flat heat storage layer 10, and the cavity part 17 which enclosed air was provided inside, but it replaces with this, FIG. As shown in a), the cavity 17 may be formed by providing the heat storage layer 10 with a recess 16 and closing it with a flat insulating substrate 9. Moreover, as shown in FIG. 9B, the hollow portion 17 may be formed by providing and combining the concave portions 16 in both the heat storage layer 10 and the insulating substrate 9.

In any case, the inner surface of the cavity 17 on the heat storage layer 10 side is preferably formed smoothly, and the inner surface of the cavity 17 on the insulating substrate 9 side is preferably formed with a surface roughness Ra of 0.2 μm or more. As a result, heat transfer from the heat storage layer 10 to the gas layer in the cavity 17 is suppressed, heat transfer from the gas layer to the insulating substrate 9 is promoted, and inconvenience that the cavity 17 becomes a heat source is generated in advance. Can be prevented.
Moreover, when providing the recessed part 16 in the thermal storage layer 10 side, it is preferable that the thickness of the thinnest part of the thermal storage layer 10 is 2 micrometers or more and 100 micrometers or less.

Alternatively, the hollow portion 17 may be formed by providing the concave portions 16 on both joint surfaces of the insulating substrate 9 and the heat storage layer 10 and combining them.
The hollow portion 17 may be filled with an inert gas such as N 2, He, or Ar instead of air. As a result, even if gas passes through the heat storage layer 10 and reaches the heat generating resistor 11, the heat generating resistor 11 is prevented from being oxidized or deteriorated in characteristics, and reliability and durability can be improved. it can.
Moreover, the cavity part 17 may be sealed and the inside of the cavity part 17 may be depressurized to atmospheric pressure or less. Thereby, the heat insulation effect by the cavity part 17 can be improved.

  Further, in the present embodiment, the cavity portion 17 is individually provided so as to oppose each of the heating resistors 11, but instead, as shown in FIG. You may decide to provide the common recessed part 16 'and cavity part 17' which oppose.

1 is a longitudinal sectional view illustrating a configuration of a thermal printer according to an embodiment of the present invention. It is a front view which shows the thermal head which concerns on one Embodiment of this invention with which the thermal printer of FIG. 1 is equipped. FIG. 3 is an α-α longitudinal sectional view showing a heating resistor element according to an embodiment of the present invention provided in the thermal head of FIG. 2. It is (a) front view, (b) aa longitudinal cross-sectional view, (c) bb longitudinal cross-sectional view explaining the shape of the cavity part of the heating resistive element of FIG. It is explanatory drawing which shows the manufacturing method of the heating resistive element of FIG. 2 is a graph showing thermal response characteristics for each surface roughness of the inner surface of a cavity in the heating resistor element of FIG. 1. It is a graph which shows the relationship between the temperature of the heating resistive element after repeated heat generation, and the surface roughness of the cavity surface. It is a front view which shows the modification of the thermal head of FIG. It is a longitudinal cross-sectional view which shows the modification of the heat generating resistive element of FIG.

Explanation of symbols

1 Heating resistance element 2 Thermal head 3 Thermal printer (printer)
DESCRIPTION OF SYMBOLS 9 Insulation board | substrate 9a Joint surface 10 Heat storage layer 11 Heating resistor 16, 16 'Concave part 17, 17'

Claims (11)

An insulating substrate, a heat storage layer bonded to the surface of the insulating substrate, and a heating resistor provided on the heat storage layer,
In the region facing the heat generating resistor on the joint surface between the insulating substrate and the heat storage layer, a cavity is formed by providing a recess in at least one of the insulating substrate or the heat storage layer,
A heating resistance element in which the inner surface of the cavity on the insulating substrate side is processed to have a surface roughness Ra of 0.2 μm or more.   The heating resistance element according to claim 1, wherein a depth of the hollow portion is 1 μm or more and 100 μm or less.   The heating resistance element according to claim 1 or 2, wherein the insulating substrate and the heat storage layer are made of alkali-free glass.   The said insulated substrate and the said thermal storage layer are joined by heating to the temperature between a slow cooling point and a softening point in the state which mutually contact | adhered the said joint surface of both. 4. The heating resistor element according to any one of 3 above.   The heating resistance element according to any one of claims 1 to 4, wherein the hollow portion is sealed with respect to the outside, and gas is sealed inside.   The heating resistor element according to claim 5, wherein the gas is an inert gas.   A thermal head comprising the heating resistor element according to any one of claims 1 to 6.   A printer comprising the thermal head according to claim 7. A recess forming step for forming a recess in at least one of the joint surfaces of the insulating substrate and the heat storage layer;
A bonding step of bonding the bonding surfaces of the insulating substrate and the heat storage layer to each other and bonding them;
A resistor forming step of forming a heating resistor at a position facing the recess on the heat storage layer;
The method for manufacturing a heating resistor element, wherein the recess forming step treats the inner surface of the recess on the insulating substrate side to a surface roughness Ra of 0.2 μm or more.   The heating resistor element manufacturing method according to claim 9, wherein the recess forming step forms the recess by sandblasting.   The method for manufacturing a heating resistor element according to claim 9, wherein the recess forming step forms the recess by high-temperature pressure molding using a mold.

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