CN116160779A - Laminate, thermal head, thermal printer, method for forming heat storage layer, and method for manufacturing thermal head - Google Patents

Abstract

The invention provides a laminate used in a thermal print head capable of ensuring good printing performance. In addition, the invention also provides a thermal printing head comprising the laminated body. In addition, a thermal printer comprising the thermal print head is also provided. Further, a method for forming a heat storage layer used in a thermal head capable of ensuring good printing performance is provided. Further, a method for manufacturing a thermal head having a heat storage layer formed by the method for forming a heat storage layer is provided. The laminate (10) comprises: an insulator having a main surface (15A) with a linear concave portion (15A); and a heat storage layer (13) which is in contact with a corner (15C) formed by the intersection of the main surface (15A) and the side surface (15B) of the recess (15A), and at least a part of which is disposed at a position higher than the height of the main surface (15A).

Description

Laminate, thermal head, thermal printer, method for forming heat storage layer, and method for manufacturing thermal head

Technical Field

The invention relates to a laminate, a thermal head, a thermal printer, a method for forming a heat storage layer, and a method for manufacturing a thermal head.

Background

The thermal head includes, for example, a plurality of heat generating portions arranged in a main scanning direction on a head substrate (see patent document 1). Each heat generating portion is formed by: the common electrode and the individual electrode are laminated on the resistor layer formed on the head substrate with a glaze layer (also referred to as a heat storage layer) interposed therebetween so that a part of the resistor layer is exposed, and the respective ends of the common electrode and the individual electrode face each other. By applying current between the common electrode and the individual electrode, the exposed portion (heat generating portion) of the resistor layer generates heat due to joule heat. The heat is transferred to a printing medium (such as thermal paper used for producing barcode paper or receipt), and the printing medium is printed.

The glaze layer functions as a heat storage layer and stores heat generated from the heat generating portion. For example, glass material such as amorphous glass having a softening point of 800 to 850 ℃ is used for the glaze layer, and the glass material is made of Al ₂ O ₃ The ceramic head substrate is formed by applying a glass paste by screen printing or the like, drying the applied glass paste, and then performing a firing process.

Another example of a conventional thermal head is disclosed in patent document 2. The thermal printhead also includes: a substrate (head substrate); a common electrode and a plurality of individual electrodes disposed on the substrate; and a heating resistor (resistor layer) electrically connected to the common electrode and the plurality of individual electrodes. The heating resistor is formed on the glaze layer. In addition to the heat storage function, the glaze layer has a function of preventing defects caused by the surface roughness of the substrate from being generated on the electrode. In this configuration, a predetermined portion (heat generating portion) of the heat generating resistor selectively generates heat in response to the current passing through the common electrode and the plurality of individual electrodes, thereby performing dot printing on the recording medium (printing medium).

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2012-121283.

Patent document 2: japanese patent application laid-open No. 2011-240641.

Disclosure of Invention

Problems to be solved by the invention

Since the surface of the head substrate made of ceramic or the like has a large arithmetic average roughness, the roughness of the surface of the head substrate follows the surface of the glaze layer formed on the surface of the head substrate, and the end portion of the glaze layer cannot be formed in a straight line, and eventually, a meandering shape is formed, or the thickness varies. Due to the glaze layer in this state, unevenness may occur in printing, so that printing performance may be lowered. It is an object of one aspect of the present invention to provide a laminate in a thermal printhead that can be used to ensure good printing performance. In addition, another object of the present invention is to provide a thermal head including the laminate. In addition, it is an object of other aspects of the present invention to provide a thermal printer including the thermal print head. Another object of the present invention is to provide a method for forming a heat storage layer in a thermal head that can be used to ensure good printing performance. Another object of the present invention is to provide a method for manufacturing a thermal head including a thermal storage layer formed by the method for forming a thermal storage layer.

In addition, in the thermal head disclosed in patent document 2, if the heat storage performance of the glaze layer is lowered, the power consumption of the thermal head increases. In particular, in cold regions, the heat storage performance of the glaze layer may be lowered. Therefore, in order to suppress an increase in power consumption of the thermal head, it is required to improve heat storage of the glaze layer.

Means for solving the problems

According to one embodiment of the present invention, a linear concave portion is provided in a main surface of an insulator, and a heat storage layer is formed by arranging a heat storage layer paste along a corner portion by surface tension of the heat storage layer paste at the corner portion by a corner portion where a side surface of the concave portion intersects the main surface, and drying and sintering the heat storage layer paste. The thermal storage layer is formed in this way, and good printing performance of the thermal head can be ensured.

According to one embodiment of the present invention, there is provided a laminate including: an insulator having a main surface with a linear first concave portion; and a heat storage layer that is in contact with a corner formed by the intersection of the main surface and the side surface of the first concave portion, and at least a part of which is disposed at a position higher than the height of the main surface.

In addition, according to other embodiments of the present invention, there is provided a thermal print head including: the laminate; a heating resistor disposed on the heat storage layer of the laminate; a separate electrode electrically connected to the heating resistor; and a common electrode electrically connected to the heat generating resistor, the individual electrode being spaced apart from and opposed to the common electrode.

In addition, according to other embodiments of the present invention, there is provided a thermal printer including the thermal print head.

Further, according to another embodiment of the present invention, there is provided a method for forming a heat storage layer, wherein a first concave portion is formed by roughening a main surface of an insulator, a heat storage layer paste is applied so as to be in contact with a corner portion formed by intersecting a side surface of the first concave portion with the main surface, the heat storage layer paste is dried and sintered to form a heat storage layer, and at least a part of the heat storage layer is disposed at a position higher than a height of the main surface.

Further, according to another embodiment of the present invention, there is provided a method for manufacturing a thermal head, wherein a thermal storage layer is formed by using the method for forming a thermal storage layer, a heat generating resistor is formed on the thermal storage layer, a single electrode electrically connected to the heat generating resistor is formed, and a common electrode electrically connected to the heat generating resistor is formed, the single electrode being formed so as to face the common electrode with a space therebetween.

In addition, according to other embodiments of the present invention, there is provided a thermal print head including: a substrate; a first glaze layer covering at least a portion of the substrate; a resistor layer including a plurality of heat generating portions, which is located on the opposite side of the substrate with respect to the first glaze layer in the 1 st direction; and a wiring layer which is in conduction with the plurality of heat generating portions and is arranged in contact with the resistor layer, wherein the plurality of heat generating portions are arranged along a 2 nd direction orthogonal to the 1 st direction, and the first glaze layer contains a filler having a hollow portion.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a laminate for use in a thermal head capable of ensuring good printing performance can be provided. In addition, a thermal print head including the laminate can also be provided. In addition, a thermal printer including a thermal print head can also be provided. In addition, a method of forming a heat storage layer used in a thermal head capable of ensuring good printing performance can be provided. Further, a method for manufacturing a thermal head having a heat storage layer formed by the method for forming a heat storage layer can be provided. In addition, by improving the heat storage performance of the glaze layer, the increase in power consumption of the thermal head can be suppressed.

Drawings

Fig. 1 is a partial perspective view illustrating a laminate of embodiment 1.

Fig. 2 is a partial sectional view along the line A-A of fig. 1 in the main scanning direction X.

Fig. 3 is a partial sectional view along the line B-B of fig. 1 in the sub-scanning direction Y.

Fig. 4 is a partial perspective view illustrating a method for producing a laminate according to embodiment 1.

Fig. 5 is a partial sectional view along the line A-A of fig. 4 in the main scanning direction X.

Fig. 6 is a partial sectional view along the line B-B of fig. 4 in the sub-scanning direction Y.

Fig. 7 is a partial perspective view illustrating a laminated body according to modification 1.

Fig. 8 is a partial sectional view along the line A-A of fig. 7 in the main scanning direction X.

Fig. 9 is a partial sectional view along the line B-B of fig. 7 in the sub-scanning direction Y.

Fig. 10 is a partial perspective view illustrating a method for producing a laminate according to modification 1.

Fig. 11 is a partial sectional view along the line A-A of fig. 10 in the main scanning direction X.

Fig. 12 is a partial sectional view along the line B-B of fig. 10 in the sub-scanning direction Y.

Fig. 13 is a partial perspective view illustrating a laminated body according to modification 2.

Fig. 14 is a partial sectional view taken along the line A-A of fig. 13 in the main scanning direction X.

Fig. 15 is a partial sectional view along the line B-B of fig. 13 in the sub-scanning direction Y.

Fig. 16 is a partial perspective view illustrating a method for producing a laminate according to modification 2.

Fig. 17 is a partial sectional view along the line A-A of fig. 16 in the main scanning direction X.

Fig. 18 is a partial sectional view along the line B-B of fig. 16 in the sub-scanning direction Y.

Fig. 19 is a partial perspective view illustrating a thermal head according to embodiment 2.

Fig. 20 is a partial sectional view along the line A-A of fig. 19 in the main scanning direction X.

Fig. 21 is a partial sectional view along the line B-B of fig. 19 in the sub-scanning direction Y.

Fig. 22 is a partial perspective view (1) illustrating a method of manufacturing a thermal head according to embodiment 2.

Fig. 23 is a partial sectional view taken along the line A-A of fig. 22 in the main scanning direction X.

Fig. 24 is a partial sectional view along the line B-B of fig. 22 in the sub-scanning direction Y.

Fig. 25 is a partial perspective view (2) illustrating a method of manufacturing a thermal head according to embodiment 2.

Fig. 26 is a partial sectional view taken along the line A-A of fig. 25 in the main scanning direction X.

Fig. 27 is a partial sectional view along the line B-B of fig. 25 in the sub-scanning direction Y.

Fig. 28 is a partial perspective view (3) illustrating a method of manufacturing a thermal head according to embodiment 2.

Fig. 29 is a partial sectional view along the line A-A of fig. 28 in the main scanning direction X.

Fig. 30 is a partial sectional view along the line B-B of fig. 28 in the sub-scanning direction Y.

Fig. 31 is a sectional view illustrating the thermal head and the thermal printer according to embodiment 3 including the thermal head.

Fig. 32 is a plan view of a thermal head according to embodiment 4 of the present invention.

Fig. 33 is a bottom view of the thermal printhead shown in fig. 32.

Fig. 34 is a cross-sectional view taken along line A-A of fig. 32.

Fig. 35 is a partially enlarged plan view of the thermal print head shown in fig. 32.

Fig. 36 is a partial enlarged view of fig. 35.

Fig. 37 is a cross-sectional view taken along line A-A of fig. 36.

Fig. 38 is a sectional view taken along line B-B of fig. 36.

Fig. 39 is a partial enlarged view of fig. 37.

Fig. 40 is a partial enlarged view of fig. 39.

Fig. 41 is a partial enlarged view of fig. 36.

Fig. 42 is a partially enlarged plan view of a thermal head according to embodiment 5 of the present invention.

Fig. 43 is a cross-sectional view taken along line A-A of fig. 42.

Fig. 44 is a sectional view taken along line B-B of fig. 42.

Fig. 45 is a sectional view illustrating a manufacturing process of the thermal head shown in fig. 42.

Fig. 46 is a sectional view illustrating a manufacturing process of the thermal head shown in fig. 42.

Fig. 47 is a cross-sectional view of a thermal head according to a modification of embodiment 5 of the present invention.

Fig. 48 is a cross-sectional view of the thermal print head shown in fig. 47, the cross-sectional position of which is different from that of fig. 47.

Fig. 49 is a plan view of a thermal head according to embodiment 6 of the present invention.

Fig. 50 is a plan view of a main portion of the thermal head shown in fig. 49.

Fig. 51 is a partial enlarged view of fig. 50.

Fig. 52 is a cross-sectional view taken along line A-A of fig. 49.

Fig. 53 is a cross-sectional view of a main portion of the thermal head shown in fig. 49.

Fig. 54 is a partial enlarged view of fig. 53.

Fig. 55 is a partially enlarged plan view of a main portion of a thermal head according to embodiment 7 of the present invention.

Fig. 56 is a cross-sectional view taken along line A-A of fig. 55.

Fig. 57 is a sectional view taken along line B-B of fig. 55.

Fig. 58 is a partial enlarged view of fig. 56.

Fig. 59 is a partial enlarged view of fig. 57.

Detailed Description

Next, embodiments of the present invention will be described with reference to the drawings. In the drawings described below, the same or similar parts are denoted by the same or similar reference numerals. It should be noted, however, that the drawings are only schematic drawings, and the relationship between the thickness and the planar dimension of each member and the like are different from those of actual ones. Accordingly, the specific thickness and dimensions should be determined with reference to the following description. It is needless to say that the drawings include portions having different dimensional relationships and ratios from each other.

The embodiments described below are embodiments that illustrate an apparatus or a method for embodying the technical idea, and do not particularly define the material, shape, structure, arrangement, and the like of each member. According to the present embodiment, various modifications can be added to the technical means.

The present invention includes, for example, the embodiments described in the following supplementary notes (corresponding to fig. 1 to 31).

Appendix 1. A laminate comprising: an insulator having a main surface with a linear first concave portion; and a heat storage layer that is in contact with a corner formed by the intersection of the main surface and the side surface of the first concave portion, and at least a part of which is disposed at a position higher than the height of the main surface.

Supplementary note 2 the laminate according to supplementary note 1, wherein linear ends of the heat storage layer are formed along the corners of the insulator.

The laminate according to appendix 1 or appendix 2, wherein the arithmetic average roughness of the bottom surface of the first recess is greater than the arithmetic average roughness of the main surface.

The laminate according to any one of supplementary notes 1 to 3, wherein the remaining part of the heat storage layer has a portion disposed inside the first concave portion.

The laminate according to any one of supplementary notes 5, wherein the main surface further has a linear second concave portion extending parallel to the first concave portion, and the heat storage layer is disposed above the main surface between the first concave portion and the second concave portion.

The laminate according to any one of supplementary notes 1 to 5, wherein the heat storage layer has a tapered portion above the main surface in a cross section of the heat storage layer perpendicular to the main surface.

The laminate according to any one of supplementary notes 7 to 6, wherein the insulator is a substrate.

The laminate according to item 7, wherein the substrate is made of any one selected from the group consisting of ceramics and silicon.

Supplementary note 9. A thermal printhead, comprising: the laminate according to any one of supplementary notes 1 to 8; a heating resistor disposed on the heat storage layer of the laminate; a separate electrode electrically connected to the heating resistor; and a common electrode electrically connected to the heat generating resistor, the individual electrode being spaced apart from and opposed to the common electrode.

Supplementary note 10. A thermal printer comprising a thermal print head as described in supplementary note 9.

The supplementary note 11 is a method for forming a heat storage layer, wherein a first recess is formed by roughening a main surface of an insulator, a heat storage layer paste is applied so as to contact a corner formed by intersecting a side surface of the first recess with the main surface, the heat storage layer paste is dried and sintered to form a heat storage layer, and at least a part of the heat storage layer is disposed at a position higher than a height of the main surface.

The method for forming a heat storage layer according to item 11, wherein a linear end portion of the heat storage layer is formed along the corner portion of the insulator.

The method for forming a heat storage layer according to any one of supplementary notes 11 and 12, wherein the roughening treatment is performed by wet spraying.

The method for forming a heat storage layer according to any one of supplementary notes 11 to 13, wherein the first concave portion is formed by removing a part of the insulator by a dicing machine and roughening the removed insulator.

The method for forming a heat storage layer according to any one of supplementary notes 11 to 14, wherein the heat storage layer paste is disposed in the first recess in the step of applying the heat storage layer paste.

The method for forming a heat storage layer according to any one of supplementary notes 16 to 15, wherein the main surface is roughened to form a linear second concave portion extending parallel to the first concave portion, and the heat storage layer paste is applied on top of the main surface between the first concave portion and the second concave portion in the step of applying the heat storage layer paste.

The method for forming a heat storage layer according to any one of supplementary notes 17 to 16, wherein the heat storage layer has a tapered portion above the main surface in a cross section of the heat storage layer perpendicular to the main surface.

The method for forming a heat storage layer according to any one of supplementary notes 11 to 17, wherein the insulator is a substrate.

The method for forming a heat storage layer according to supplementary note 19, wherein the substrate is made of any one selected from ceramics and silicon.

A thermal head manufacturing method according to any one of supplementary notes 20, wherein a thermal storage layer is formed by using the method for forming a thermal storage layer according to any one of supplementary notes 11 to 19, a heat generating resistor is formed on the thermal storage layer, a single electrode electrically connected to the heat generating resistor is formed, and a common electrode electrically connected to the heat generating resistor is formed, the single electrode being formed so as to be opposed to the common electrode with a space therebetween.

(embodiment 1)

A laminated body according to embodiment 1 of the present invention will be described with reference to the drawings.

Fig. 1 is a partial perspective view showing a laminate 10 that can be used for a thermal head. Fig. 2 is a partial sectional view along the line A-A of fig. 1 in the main scanning direction X. Fig. 3 is a partial sectional view along the line B-B of fig. 1 in the sub-scanning direction Y. The laminated body 10 includes a substrate 15 as an insulator and a heat storage layer 13 on the substrate 15. The substrate 15 includes a main surface 15A having a linear concave portion 15A.

In the present embodiment, the direction in which the concave portion 15A linearly extends is referred to as the main scanning direction X, the direction perpendicular to the main scanning direction X and parallel to the main surface 15A of the substrate 15 is referred to as the sub-scanning direction Y, and the direction corresponding to the thickness of the substrate 15 is referred to as the thickness direction Z. The thickness direction Z is a direction perpendicular to the main scanning direction X and the sub scanning direction Y, respectively. The direction in which the heat storage layer 13 is located when viewed from the substrate 15 is set to be the upper direction, and the direction in which the substrate 15 is located when viewed from the heat storage layer 13 is set to be the lower direction.

The substrate 15 is an insulator, and is made of, for example, ceramic or single crystal semiconductor. As the ceramic, for example, alumina or the like can be used. As the single crystal semiconductor substrate, a silicon substrate or the like can be used, for example. From the viewpoint of heat dissipation, alumina having relatively large thermal conductivity is preferably used for the substrate 15.

In general, the arithmetic average roughness (Ra) of the surface of a substrate made of ceramic or single crystal semiconductor is large, for example, 0.5 μm or less. Further, ra may conform to JIS B0601, for example: 2013 or ISO 25178. If Ra of the surface of the substrate is large, the irregularities of the surface of the substrate follow the surface of the heat storage layer formed on the surface of the substrate, and the end portion of the heat storage layer is not formed in a straight line but is formed in a meandering shape, or the thickness is deviated.

In order to solve these problems, in the present embodiment, a linear concave portion 15A is provided on the main surface 15A of the substrate 15, and a corner portion 15C formed by intersecting the main surface 15A with the side surface 15B of the concave portion 15A is used. By arranging the heat-storage layer paste along the corner 15C using the surface tension of the heat-storage layer paste at the corner 15C, and drying and sintering the heat-storage layer paste, the heat-storage layer 13 having the linear end portion 13A formed along the corner 15C in contact with the corner 15C can be obtained. Further, since the width of the concave portion 15a in the sub-scanning direction Y is the width of the heat storage layer 13, the width of the heat storage layer 13 in the sub-scanning direction Y can be adjusted by adjusting the width of the concave portion 15 a.

If the heat-storage-layer paste is low in viscosity, the heat-storage-layer paste disposed on the corner 15C side dries quickly, and therefore the surface tension of the heat-storage-layer paste at the corner 15C is slightly higher than that of the inner portion (central portion) of the heat-storage-layer paste. As a result, the heat-storage layer paste disposed on the corner 15C side pulls the heat-storage layer paste disposed in the central portion, and eventually becomes a shape of the corner 15C side bulge. In addition, if the heat-storage-layer paste has a high viscosity, fluidity of the heat-storage-layer paste is reduced, and irregularities are likely to occur on the surface of the heat-storage-layer paste.

In the present embodiment, the viscosity of the heat storage layer paste is preferably 50 to 200pa·s, for example. When the viscosity of the heat-storage-layer paste is appropriately adjusted, molecules of a material constituting the heat-storage-layer paste are pulled toward each other by the surface tension of the heat-storage-layer paste to reduce the surface area of the heat-storage-layer paste, so that the corner 15C becomes thinner, and the heat-storage-layer paste has a tapered portion that gradually becomes thicker from the corner 15C toward the central portion. Since the heat-storage layer paste has a tapered portion, the heat-storage layer 13 having a tapered portion can be obtained by subjecting it to drying and sintering treatment.

Further, since the recess 15A described later is formed by roughening the main surface 15A of the substrate 15, ra of the bottom surface 15D of the recess 15A is larger than Ra of the main surface 15A. By roughening, ra of the entire bottom surface 15D becomes uniform, and molecules of the material constituting the heat-storage-layer paste randomly drag each other, whereby meandering of the heat-storage-layer paste and variation in thickness can be suppressed. Therefore, by drying and sintering the heat-storage-layer paste in which the meandering and thickness variation is suppressed, the heat storage layer 13 in which the meandering and thickness variation is suppressed can be obtained. Further, by roughening treatment, adhesion between the heat storage layer paste and the bottom surface 15D as the roughened surface can be improved. Therefore, the heat storage layer 13 having good adhesion to the bottom surface 15D can be obtained.

A heat storage layer 13 having a function of storing heat is laminated on the substrate 15. The heat storage layer 13 stores heat generated from a heat generating resistor unit described later in embodiment 2. The heat storage layer 13 (heat storage layer paste) may be made of an insulating material, for example, silicon oxide or silicon nitride, which is a main component of glass. The dimension of the heat storage layer 13 in the thickness direction Z is not particularly limited, and is, for example, 5 to 100 μm, preferably 10 to 30 μm.

The heat storage layer 13 is in contact with the corner 15C of the substrate 15 and is disposed in the recess 15A, and the upper surface of the heat storage layer 13 is disposed above the height of the main surface 15A.

The heat storage layer 13 is formed with linear end portions 13A along the corner portions 15C. By forming the linear end portion 13A, not only meandering and thickness variation of the heat storage layer 13 but also uneven printing can be suppressed, and a thermal head that ensures good printing performance can be obtained.

Here, a method for manufacturing the laminated body 10 (a method for forming the heat storage layer 13) according to the present embodiment will be described.

As shown in fig. 4 to 6, first, a substrate 15 is prepared, and a main surface 15A of the substrate 15 is roughened to form a linear concave portion 15A. The recess 15a has a side surface 15B and a bottom surface 15D. The substrate 15 has a corner 15C where the side surface 15B intersects the main surface 15A.

As the roughening treatment, for example, wet blasting, air blasting, shot blasting, sand blasting, or the like can be used, but wet blasting is particularly preferable from the viewpoints of uniformity, controllability, cleaning, and the like of the bottom surface 15D as the roughened surface. As a result, ra of the entire bottom surface 15D becomes uniform, and molecules of the material constituting the heat-storage-layer paste to be applied later randomly drag each other, whereby meandering of the heat-storage-layer paste and variation in thickness can be suppressed. In addition, the adhesion between the heat storage layer paste and the bottom surface 15D, which is the roughened surface, can be improved.

Before roughening the main surface 15A of the substrate 15, a part of the main surface 15A may be removed along a dicing line provided on the main surface 15A of the substrate 15 by a dicing machine or the like, and the removed part may be roughened. By removing a part of the main surface 15A by a cutter or the like and roughening the removed portion, the corner 15C can be formed into a straight line shape, the meandering of the heat-storage layer paste and the variation in thickness can be suppressed, and the adhesion between the bottom surface 15D, which is the roughened surface, and the heat-storage layer paste can be improved.

Next, a heat storage layer paste is applied by screen printing or the like so as to be placed in contact with the corner 15C and in the recess 15A and above the height of the main surface 15A. Then, as shown in fig. 1 to 3, the heat storage layer paste is dried and sintered to form the heat storage layer 13. The sintering treatment is carried out, for example, at 800 to 1200 ℃ for 10 minutes to 1 hour. The dimension (thickest portion) of the heat storage layer 13 in the thickness direction Z is, for example, 25 μm.

Through the above steps, the laminate 10 of the present embodiment can be manufactured.

According to the present embodiment, a laminate is provided in which a linear concave portion formed by roughening a main surface of a substrate is provided, a thermal storage layer paste is disposed along a corner portion by a surface tension of the thermal storage layer paste at the corner portion by using a corner portion formed by intersecting a main surface with a side surface of the concave portion, and the thermal storage layer paste is dried and sintered, whereby a thermal storage layer having excellent adhesion to a bottom surface of the concave portion and excellent printing performance can be obtained while suppressing meandering and thickness variation.

The laminate of the present embodiment is not limited to the above-described configuration, and various modifications can be made. A modified example of the laminate of the present embodiment will be described below.

< modification 1 >

The structure of the laminated body 20 of this modification will be described. Fig. 7 is a partial perspective view showing a laminate 20 that can be used in a thermal head. Fig. 8 is a partial sectional view along the line A-A of fig. 7 in the main scanning direction X. Fig. 9 is a partial sectional view along the line B-B of fig. 7 in the sub-scanning direction Y. The laminated body 20 includes a substrate 25 as an insulator and a heat storage layer 23 on the substrate 25. The substrate 25 includes a main surface 25A having a plurality of linear recesses 25A. The laminate 20 of the present modification differs from the laminate 10 shown in fig. 1 to 3 described above in that a plurality of linear concave portions 25a are provided. In this modification, the common points with the laminated body 10 shown in fig. 1 to 3 are the same as those described above, and the differences will be described below.

In the present modification, the direction in which the concave portion 25A linearly extends is referred to as the main scanning direction X, the direction perpendicular to the main scanning direction X and parallel to the main surface 25A of the substrate 25 is referred to as the sub-scanning direction Y, and the direction corresponding to the thickness of the substrate 25 is referred to as the thickness direction Z. The thickness direction Z is a direction perpendicular to the main scanning direction X and the sub scanning direction Y, respectively. The direction in which the heat storage layer 23 is located when viewed from the substrate 25 is set to be the upper direction, and the direction in which the substrate 25 is located when viewed from the heat storage layer 23 is set to be the lower direction.

In the present modification, a plurality of linear concave portions 25A extending parallel to each other are provided on the main surface 25A of the substrate 25, and the corners 25C formed by intersecting the main surface 25A with the side surfaces 25B of the concave portions 25A are used. The heat storage layer paste is disposed along the corner 25C by the surface tension of the heat storage layer paste at the corner 25C, and the heat storage layer 23 having the linear end 23A formed along the corner 25C in contact with the corner 25C can be obtained by drying and sintering the heat storage layer paste. Further, since the distance between the side surface 25B of the concave portion 25a and the side surface 25B of the other concave portion 25a becomes the width of the heat storage layer 23 in the sub-scanning direction Y, the width of the heat storage layer 23 in the sub-scanning direction Y can be adjusted by adjusting the distance.

Further, since the recess 25A described later is formed by roughening the main surface 25A of the substrate 25, ra of the bottom surface 25D of the recess 25A is larger than Ra of the main surface 25A. By roughening, ra of the entire bottom surface 25D becomes uniform, and molecules of the material constituting the heat-storage-layer paste randomly drag each other, whereby meandering of the heat-storage-layer paste and variation in thickness can be suppressed. Therefore, by drying and sintering the heat-storage-layer paste in which the meandering and thickness variation is suppressed, the heat storage layer 23 in which the meandering and thickness variation is suppressed can be obtained. Further, by roughening treatment, adhesion between the heat storage layer paste and the bottom surface 25D as the roughened surface can be improved. Therefore, the heat storage layer 23 having good adhesion to the bottom surface 25D can be obtained.

For the material of the substrate 25, an explanation of the material of the substrate 15 may be cited.

A heat storage layer 23 having a function of storing heat is laminated on the substrate 25. The heat storage layer 23 stores heat generated from a heat generating resistor unit described later in embodiment 2. The heat storage layer 23 (heat storage layer paste) may be made of an insulating material, for example, silicon oxide or silicon nitride, which is a main component of glass. The dimension of the heat storage layer 23 in the thickness direction Z is not particularly limited, and is, for example, 5 to 100 μm, preferably 10 to 30 μm.

The heat storage layer 23 is in contact with the corner 25C of the substrate 25, and is disposed in the main surface 25A between the concave portions 25A and the inside of the concave portion 25A, and the upper surface of the heat storage layer 23 is disposed above the height of the main surface 25A.

The heat storage layer 23 is formed with linear end portions 23A along the corner portions 25C. By forming the linear end portion 23A, not only meandering and thickness variation of the heat storage layer 23 but also occurrence of printing unevenness can be suppressed, and a thermal head ensuring good printing performance can be obtained.

Here, a method for manufacturing the laminated body 20 (a method for forming the heat storage layer 23) according to the present embodiment will be described.

As shown in fig. 10 to 12, first, a substrate 25 is prepared, and a main surface 25A of the substrate 25 is roughened to form a plurality of linear recesses 25A. The recess 25a has a side surface 25B and a bottom surface 25D. The substrate 25 has a corner 25C where the side surface 25B intersects the main surface 25A.

The roughening treatment may be referred to as description of the method for producing the laminate 10. Before roughening the main surface 25A of the substrate 25, a part of the main surface 25A may be removed along a dicing line provided on the main surface 25A of the substrate 25 by a dicing machine or the like, and the removed part may be roughened.

Next, the heat storage layer paste is applied by screen printing or the like so as to be in contact with the corner 25C and disposed on the main surface 25A between the recesses 25A, inside the recesses 25A, and above the height of the main surface 25A. Then, as shown in fig. 7 to 9, the heat storage layer paste is dried and sintered to form the heat storage layer 23. The sintering treatment is carried out, for example, at 800 to 1200 ℃ for 10 minutes to 1 hour. The dimension (thickest portion) of the heat storage layer 23 in the thickness direction Z is, for example, 25 μm.

Through the above steps, the laminate 20 of the present embodiment can be manufactured.

According to this modification, a laminated body can be provided in which a region where roughening treatment is performed on the main surface can be reduced by providing a plurality of linear concave portions extending parallel to each other, and thus the manufacturing process can be simplified. Further, by providing a plurality of linear recesses formed by roughening the main surface of the substrate, disposing the heat-storage layer paste along the corners by the surface tension of the heat-storage layer paste at the corners by using the corners where the sides of the recesses intersect the main surface, and drying and sintering the heat-storage layer paste, the meandering and thickness variations can be suppressed, and a heat-storage layer having good adhesion to the bottom surface of the recesses can be obtained, which can be used for a thermal head ensuring good printing performance.

< modification example 2 >

The structure of the laminated body 30 of this modification will be described. Fig. 13 is a partial perspective view showing a laminate 30 that can be used for a thermal head. Fig. 14 is a partial sectional view taken along the line A-A of fig. 13 in the main scanning direction X. Fig. 15 is a partial sectional view along the line B-B of fig. 13 in the sub-scanning direction Y. The laminated body 30 includes a substrate 35 as an insulator and a heat storage layer 33 on the substrate 35. The substrate 35 includes a main surface 35A having a plurality of linear recesses 35A. The laminate 30 of the present modification differs from the laminate 10 shown in fig. 1 to 3 described above in that a plurality of linear concave portions 35A are provided, and the heat storage layer 33 is disposed above the principal surface 35A between the concave portions 35A. In this modification, the common points with the laminated body 10 shown in fig. 1 to 3 are the same as those described above, and the differences will be described below.

In the present modification, the direction in which the concave portion 35A linearly extends is referred to as the main scanning direction X, the direction perpendicular to the main scanning direction X and parallel to the main surface 35A of the substrate 35 is referred to as the sub-scanning direction Y, and the direction corresponding to the thickness of the substrate 35 is referred to as the thickness direction Z. In other words, the thickness direction Z is a direction perpendicular to the main scanning direction X and the sub scanning direction Y, respectively. The direction in which the heat storage layer 33 is located when viewed from the substrate 35 is set to be the upper direction, and the direction in which the substrate 35 is located when viewed from the heat storage layer 33 is set to be the lower direction.

In the present modification, a plurality of linear recesses 35A extending parallel to each other are provided in the main surface 35A of the substrate 35, and corners 35C formed by intersecting the main surface 35A with the side surfaces 35B of the recesses 35A are used. The heat storage layer paste is placed along the corner portions 35C by the surface tension of the heat storage layer paste at the corner portions 35C, and the heat storage layer paste is dried and sintered to obtain the heat storage layer 33 having the linear end portions 33A along the corner portions 35C in contact with the corner portions 35C. Further, since the interval between the concave portions 35a becomes the width of the heat storage layer 33 in the sub-scanning direction Y, the width of the heat storage layer 33 in the sub-scanning direction Y can be adjusted by adjusting the interval.

For the material of the substrate 35, an explanation of the material of the substrate 15 may be cited.

A heat storage layer 33 having a function of storing heat is laminated on the substrate 35. The heat storage layer 33 stores heat generated from a heat generating resistor unit described later in embodiment 2. The heat storage layer 33 (heat storage layer paste) may be made of an insulating material, for example, silicon oxide or silicon nitride, which is a main component of glass. The dimension of the heat storage layer 33 in the thickness direction Z is not particularly limited, and is, for example, 5 to 100 μm, preferably 10 to 30 μm.

The heat storage layer 33 is in contact with the corner 35C of the substrate 35 and is disposed above the main surface 35A between the concave portions 35A.

The heat storage layer 33 is formed with linear end portions 33A along the corner portions 35C. By forming the linear end portion 33A, not only meandering and thickness variation of the heat storage layer 33 but also occurrence of printing unevenness can be suppressed, and a thermal head ensuring good printing performance can be obtained.

Here, a method for manufacturing the laminated body 30 (a method for forming the heat storage layer 33) according to the present embodiment will be described.

As shown in fig. 16 to 18, first, a substrate 35 is prepared, and a main surface 35A of the substrate 35 is roughened to form a plurality of linear recesses 35A. The recess 35a has a side face 35B and a bottom face 35D. The substrate 35 has a corner 35C where the side surface 35B intersects the main surface 35A.

The roughening treatment may be referred to as description of the method for producing the laminate 10. Before roughening the main surface 35A of the substrate 35, a part of the main surface 35A may be removed along a dicing line provided on the main surface 35A of the substrate 35 by a dicing machine or the like, and the removed part may be roughened.

Next, the heat storage layer paste is applied by screen printing or the like so as to be in contact with the corner portions 35C and disposed on the main surface 35A between the concave portions 35A. Then, as shown in fig. 13 to 15, the heat storage layer paste is dried and sintered to form the heat storage layer 33. The sintering treatment is carried out, for example, at 800 to 1200 ℃ for 10 minutes to 1 hour. The dimension (thickest portion) of the heat storage layer 33 in the thickness direction Z is, for example, 25 μm.

Through the above steps, the laminate 30 of the present modification can be manufactured.

According to this modification, a laminated body can be provided in which a region where roughening treatment is performed on the main surface can be reduced by providing a plurality of linear concave portions extending parallel to each other, and thus the manufacturing process can be simplified. Further, by providing a plurality of linear recesses formed by roughening the main surface of the substrate, disposing the heat-storage layer paste along the corners by the surface tension of the heat-storage layer paste at the corners by using the corners where the sides of the recesses intersect the main surface, and drying and sintering the heat-storage layer paste, a heat-storage layer with suppressed meandering and thickness variations can be obtained, and the thermal head can be used to secure good printing performance.

(embodiment 2)

The thermal head of the present embodiment will be described with reference to the drawings. The thermal head of the present embodiment includes the laminate of embodiment 1. In the present embodiment, a description will be given of an example of a configuration in which a central portion (the heat storage layer 13 in the recess 15a and the substrate 15 below) of the laminated body 10 including the substrate 15 and the heat storage layer 13 is used. Therefore, in the following figures, the heat storage layer 13 is provided on the entire substrate 15, but is not limited thereto.

Fig. 19 is a partial perspective view showing a thermal head. Fig. 20 is a partial sectional view along the line A-A of fig. 19 in the main scanning direction X. Fig. 21 is a partial sectional view along the line B-B of fig. 19 in the sub-scanning direction Y. Fig. 19 to 21 show a part of a thermal head (corresponding to one thermal head), and in the present embodiment, the one thermal head is referred to as a single-sheet thermal head 100. The thermal head 100 has: a laminated body 10 including a substrate 15 and a heat storage layer 13; individual electrodes 31 on the heat storage layer 13 included in the laminated body 10; a common electrode 32 on the heat storage layer 13 spaced apart from the individual electrode 31 and opposed to the individual electrode 31; heating resistors 40 on the heat storage layer 13, on the individual electrode 31, and on the common electrode 32; and a protective film 34 covering the individual electrode 31, the common electrode 32, and the heat generating resistor 40. The heating resistor 40 includes a plurality of heating resistor portions 41 that generate heat by the current flowing through the individual electrodes 31 and the common electrode 32. The plurality of heating resistor portions 41 are individually formed with the respective heating resistor portions 41 between the individual electrode 31 and the common electrode 32. Fig. 19 omits the plurality of heat generating resistor portions 41. The plurality of heating resistor units 41 are arranged in a straight line on the heat storage layer 13. In addition, the protective film 34 is omitted in fig. 19 for ease of understanding.

In the present embodiment, the direction in which the plurality of heating resistor portions 41 linearly extend is referred to as the main scanning direction X, the direction perpendicular to the main scanning direction X and parallel to the upper surface of the substrate 15 is referred to as the sub-scanning direction Y, and the direction corresponding to the thickness of the substrate 15 is referred to as the thickness direction Z. In other words, the thickness direction Z is a direction perpendicular to the main scanning direction X and the sub scanning direction Y, respectively. The direction in which the heat storage layer 13 is located when viewed from the substrate 15 is set to be the upper direction, and the direction in which the substrate 15 is located when viewed from the heat storage layer 13 is set to be the lower direction.

The individual electrode 31 and the common electrode 32 formed of a metal paste are provided on the heat storage layer 13 included in the laminate 10. The individual electrodes 31 and the common electrode 32 are obtained by applying a metal paste by screen printing or the like and then sintering the applied paste to form an electrode pattern.

As the metal paste, for example, a paste containing metal particles such as copper, silver, palladium, iridium, platinum, gold, and the like can be used. Copper, silver, platinum and gold are preferable from the viewpoint of the characteristics and ionization tendency of the metal, and silver is more preferable from the viewpoint of the characteristics, ionization tendency and cost reduction of the metal. The solvent contained in the metal paste has a function of uniformly dispersing the metal particles, and examples thereof include, but are not limited to, an ester-based solvent, a ketone-based solvent, a glycol ether-based solvent, an aliphatic solvent, an alicyclic solvent, an aromatic solvent, an alcohol-based solvent, and a mixture of 1 or 2 or more of water.

Examples of the ester solvents include ethyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, amyl acetate, ethyl lactate, and dimethyl carbonate. Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone benzene, diisobutyl ketone, diacetone alcohol, isophorone, and cyclohexane. Examples of the glycol ether solvents include ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, and the like, and these monoether acetates, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and the like, and these monoether acetates, and the like.

Examples of the aliphatic solvent include n-heptane, n-hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, and the like. Examples of the alicyclic solvent include methylcyclohexane, ethylcyclohexane, and cyclohexane. Examples of the aromatic solvent include toluene, xylene, and tetralin. Examples of the alcohol solvents (excluding the glycol ether solvents described above) include ethanol, propanol, butanol, and the like.

The metal paste may contain a dispersant, a surface treatment agent, an anti-friction enhancing agent, an infrared ray absorber, an ultraviolet ray absorber, a fragrance, an antioxidant, an organic pigment, an inorganic pigment, a defoaming agent, a silane coupling agent, a titanate coupling agent, a plasticizer, a flame retardant, a humectant, an ion scavenger, and the like, as required.

The individual electrodes 31 are substantially stripe-shaped extending in the sub-scanning direction Y, and are not electrically connected to each other. Therefore, when a printer incorporating a thermal head is used, different potentials can be applied to the individual electrodes 31. A single pad portion, not shown, is connected to an end portion of each individual electrode 31.

The common electrode 32 is a portion which becomes opposite in polarity to the plurality of individual electrodes 31 when a printer incorporating a thermal head is used. The common electrode 32 has comb-teeth portions 32A and common portions 32B that commonly connect the comb-teeth portions 32A. The common portion 32B is formed along an edge of the upper side of the substrate 15 in the main scanning direction X. In the sub-scanning direction Y, the direction in which the common electrode 32 is seen from the individual electrode 31 is set to be the upper side of the sub-scanning direction Y. Each comb tooth portion 32A has a belt shape extending in the sub-scanning direction Y. The tip ends of the comb teeth 32A are opposed to the tip ends of the individual electrodes 31 at predetermined intervals along the sub-scanning direction Y. By adopting such a configuration, the pitch of the heating resistors 40 can be narrowed, and thus high-definition printing can be performed.

The heating resistor 40 is electrically connected to the individual electrode 31 and the common electrode 32, and generates heat at a portion through which current flows from the individual electrode 31 and the common electrode 32. Specifically, the heat generating resistor 40 (heat generating resistor 41) to which the heat generating voltage is applied individually according to the print signal sent from the outside to the drive IC or the like selectively generates heat. The heat generation resistor portion 41 selectively generates heat by being individually energized according to a print signal. By thus generating heat, a print dot is formed. The heating resistor 40 is made of a material having higher resistivity than the materials constituting the individual electrode 31 and the common electrode 32, and for example, ruthenium oxide or the like can be used.

The heating resistor 40 can be formed by sintering a resistor paste. In the present embodiment, the dimension of the heating resistor 40 in the thickness direction Z is, for example, about 1 to 10 μm.

The heating resistor 40 and the like are covered with the protective film 34, and the protective film 34 protects the heating resistor 40 and the like from abrasion, corrosion, oxidation, and the like. The protective film 34 may be made of an insulating material, for example, amorphous glass. The protective film 34 is formed by thick film printing of a glass paste and then sintering. The dimension in the thickness direction Z of the protective film 34 is, for example, about 2 to 8 μm. If the thickness is in this range, the thermal head 100 can be obtained, which can suppress pressure failure and can maintain good printing quality, and is therefore preferable.

Here, a method of manufacturing the thermal head 100 of the present embodiment will be described.

As shown in fig. 22 to 24, first, as described in embodiment 1, a laminate 10 including a substrate 15 and a heat storage layer 13 is prepared, and an individual electrode 31 and a common electrode 32 are formed on the heat storage layer 13. The individual electrodes 31 and the common electrode 32 are obtained by applying the above metal paste by screen printing or the like and then sintering.

Next, as shown in fig. 25 to 27, a resistor paste is formed as the heating resistor 40 (heating resistor 41). The resistor paste contains ruthenium oxide, for example. Next, the resistor paste is sintered to form the heating resistor 40 (heating resistor 41).

Next, as shown in fig. 28 to 30, a protective film 34 is formed. The protective film 34 is made of amorphous glass, for example. The protective film 34 is formed by thick film printing of a glass paste and then sintering.

Through the above steps, the thermal head 100 of the present embodiment can be manufactured.

According to the present embodiment, it is possible to provide a thermal head capable of ensuring good printing performance by including a heat storage layer which can suppress meandering and thickness variation and has good adhesion to the bottom surface of the concave portion.

As described above, embodiments 1 and 2 of the present invention have been described, but it should be understood that the descriptions and drawings forming a part of the present invention are illustrative and not restrictive. Various alternative embodiments, examples and operational techniques will be clearly understood by those skilled in the art in light of the present disclosure. Accordingly, the present invention includes various embodiments and the like not set forth herein.

(embodiment 3)

Thermal printer

As shown in fig. 31, the thermal head (for example, thermal head 100) further includes a substrate 15 (not shown in the figures such as the heat storage layer 13 on the substrate 15), a connection substrate 5, a heat sink 8, a drive IC7, a plurality of leads 81, a resin portion 82, and a connector 59. The board 15 and the connection board 5 are mounted on the heat sink 8 adjacently in the sub-scanning direction Y. A plurality of heating resistor portions 41 aligned in the main scanning direction X are formed on the substrate 15. The heat generating resistor 41 is selectively driven by heat generated by the driving IC7 mounted on the connection board 5. The heat generating resistor 41 prints on a print medium 92 such as thermal paper pressed by the platen roller 91 against the heat generating resistor 41 according to a print signal transmitted from the outside via the connector 59.

The connection substrate 5 may be, for example, a printed wiring substrate. The connection substrate 5 has a structure in which a base material layer and a wiring layer, not shown, are laminated. For example, glass epoxy resin or the like can be used as the base material layer. For example, metals such as copper, silver, palladium, iridium, platinum, and gold can be used for the wiring layer.

The heat sink 8 has a function of diffusing heat from the substrate 15. The heat sink 8 is mounted with a board 15 and a connection board 5. For example, a metal such as aluminum may be used as the heat dissipation member 8.

For example, a conductor such as gold may be used for the lead 81. The plurality of leads 81 are provided, and a part thereof connects the driver IC7 to each individual electrode by bonding. In addition, some of the other leads 81 are bonded to conduct the driver ICs 7 and the connector 59 via the wiring layer of the connection board 5.

For example, black resin may be used for the resin portion 82. As the resin portion 82, for example, epoxy resin, silicone resin, or the like can be used. The resin portion 82 covers the driver IC7 and the plurality of leads 81, and protects the driver IC7 and the plurality of leads 81. The connector 59 fixes and connects the substrate 5. A wire for supplying power to the thermal head from the outside of the thermal head and controlling the drive IC7 is connected to the connector 59.

The thermal printer of embodiment 3 of the present invention may include the thermal print head described above. The thermal printer performs printing on a printing medium conveyed along the sub-scanning direction Y. Typically, the printing medium is fed from the connector 59 side to the heat generating resistor 41 side. Examples of the printing medium include thermal paper used for producing barcode paper and receipts.

The thermal printer includes, for example, a thermal print head 100, a platen roller 91, a main power supply circuit, a circuit for measurement, and a control section. The platen roller 91 is opposed to the thermal head 100.

The main power supply circuit supplies power to the plurality of heating resistor sections 41 in the thermal head 100. The measuring circuit measures the resistance value of each of the plurality of heating resistor units 41. The measuring circuit measures the resistance value of each of the plurality of heating resistor units 41 when, for example, printing is not performed on the printing medium. This can confirm the life of the heat generating resistor 41 and the presence or absence of failure of the heat generating resistor 41. The control unit controls the driving state of the main power supply circuit and the measurement circuit. The control unit controls the energization state of each of the plurality of heating resistor units 41. The measurement circuit may be omitted.

The connector 59 is used to communicate with devices external to the thermal printhead 100. The thermal head 100 is electrically connected to a main power supply circuit and a measurement circuit via a connector 59. The thermal head 100 is electrically connected to the control section via a connector 59.

The drive IC7 receives a signal from the control section via the connector 59. The drive IC7 controls the energization state of each of the plurality of heating resistor units 41 based on the signal received from the control unit. Specifically, the driver IC7 selectively energizes the plurality of individual electrodes to generate heat in any one of the plurality of heat generation resistor sections 41.

The thermal head is not limited to the above-described configuration, and may be configured such that the driving IC7 is directly mounted on the substrate 15 without providing the connection substrate 5, flip-chip mounting is performed without providing the leads 81, or the heat dissipation member 8 is not provided.

Next, a method of using the thermal printer will be described.

When printing on a print medium, a potential V11 is applied to the connector 59 from the main power supply circuit as a potential V1 of an input signal. In this case, the plurality of heating resistor portions 41 are selectively energized and generate heat. By transferring this heat to the print medium, printing is performed on the print medium. As described above, when the potential V11 is applied as the potential V1 from the main power supply circuit to the connector 59, the current-carrying paths to the respective plural heat generating resistor sections 41 can be ensured.

When the printing medium is not printed, the resistance value of each heating resistor 41 is measured. In this measurement, no potential is applied to the connector 59 from the main power supply circuit. When the resistance value of each heating resistor 41 is measured, a potential V12 is applied as a potential V1 from the measurement circuit to the connector 59. In this case, the plurality of heat generating resistor portions 41 are energized sequentially (for example, sequentially from the heat generating resistor portions 41 located at the end portions in the main scanning direction X). Based on the current value and the potential v12 flowing through the heat generating resistor 41, the measurement circuit measures the resistance value of each heat generating resistor 41. As described above, when the potential V11 is applied as the potential V1 from the main power supply circuit to the connector 59, the conduction path to the plurality of heating resistor portions 41 is substantially cut off. Thus, the resistance value of each heating resistor 41 can be measured more accurately by the measuring circuit, and the life of the heating resistor 41 and the presence or absence of the occurrence of the failure of the heating resistor 41 can be confirmed.

According to the above, a thermal printer ensuring good printing performance can be obtained.

Description of the reference numerals

(description of the reference numerals of embodiment 1 to 3)

5: connection substrate, 7: drive IC,8: the heat-dissipating component is provided with a heat-dissipating member,

10. 20, 30: laminate, 13, 23, 33: the heat-accumulating layer is arranged on the inner surface of the heat-accumulating layer,

13A, 23A, 33A: end, 15, 25, 35: the substrate is provided with a plurality of grooves,

15a, 25a, 35a: recess, 15A, 25A, 35A: the major surface of the sheet is provided with a plurality of grooves,

15B, 25B, 35B: side surfaces, 15C, 25C, 35C: the corner portions of the two-dimensional space are provided with a plurality of grooves,

15D, 25D, 35D: bottom surface, 31: a separate electrode is provided for the electrodes,

32: common electrode, 32A: comb teeth part, 32B: a common portion of the body of the vehicle,

34: protective film, 40: heating resistor, 41: a heating resistor part, a heating resistor part and a heating resistor part,

59: connector, 81: lead wire, 82: a resin portion, which is provided with a resin layer,

91: platen roller, 92: the print medium is provided with a plurality of printing stations,

100: a thermal print head.

Next, embodiments of other aspects of the present invention will be described. These embodiments include, for example, the embodiments described in the following supplementary notes 1A to 17A (group 2 embodiment; fig. 32 to 59). The reference numerals used in fig. 32 to 59 and the following description are independent of the reference numerals used in the above-described embodiments 1 to 3 (embodiment 1 group; fig. 1 to 31). Thus, between group 1 and group 2 embodiments, the same symbols may be used for different components, or different symbols may be used for the same (or similar) components.

Supplementary note 1A. A thermal printhead, comprising: a substrate; a first glaze layer covering at least a portion of the substrate; a resistor layer including a plurality of heat generating portions, which is located on the opposite side of the substrate with respect to the first glaze layer in the 1 st direction; and a wiring layer which is in conduction with the plurality of heat generating portions and is disposed in contact with the resistor layer, wherein the plurality of heat generating portions are arranged along a 2 nd direction orthogonal to the 1 st direction, and the first glaze layer contains a filler having a hollow portion.

The thermal head according to supplementary note 2A. The thermal head according to supplementary note 1A, wherein the plurality of heat generating portions overlap the filler as seen in the 1 st direction.

The thermal head of appendix 3A. The thermal head of appendix 2A, wherein the filler has a shell portion surrounding the hollow portion, the hollow portion being vacuum.

The thermal printhead of appendix 4A. The thermal printhead of appendix 3A, wherein the composition of the shell portion comprises silica.

The thermal head according to any one of the additional notes 5A to 4A, wherein the filler has a particle diameter of 0.3 μm or more and 0.5 μm or less.

The thermal head according to any one of supplementary notes 6A to 4A, further comprising a second glaze layer located on both sides of the first glaze layer in a 3 rd direction orthogonal to the 1 st and 2 nd directions, the first glaze layer having a glass transition temperature lower than that of the second glaze layer.

The thermal head according to supplementary note 7A. The second glaze layer has a base surface facing the opposite side to the side opposite to the substrate in the 1 st direction, the base surface including a pair of end edges sandwiching the first glaze layer, the first glaze layer being in contact with the pair of end edges.

The thermal printhead of appendix 8A. Appendix 7A, wherein the first glaze layer is flush with the base surface.

The thermal printhead of appendix 9A. Appendix 8A, wherein said first glaze layer protrudes from said base surface.

The thermal head according to supplementary note 10A. The thermal head according to supplementary note 9A, wherein a peripheral edge of a portion of the first glaze layer protruding from the base surface forms a convex curve as seen in the 2 nd direction.

The thermal head according to any one of supplementary notes 11A to 4A, wherein the substrate has a main surface facing a side where the wiring layer is located in the 1 st direction and a convex portion protruding from the main surface, the convex portion has a top surface facing the 1 st direction and located at a position apart from the main surface, a first inclined surface and a second inclined surface, the 1 st inclined surface and the 2 nd inclined surface are located between the main surface and the top surface and inclined with respect to the main surface, the 1 st inclined surface and the 2 nd inclined surface are located at a position apart from each other in a 3 rd direction orthogonal to the 1 st direction and the 2 nd direction, and the 1 st glaze layer covers the top surface.

The thermal head of appendix 12A. Appendix 11A, wherein the first inclined surface and the second inclined surface are closer to the top surface from the main surface.

The thermal printhead of appendix 13A. The thermal printhead of appendix 12A, wherein the substrate comprises a semiconductor material.

The thermal head according to supplementary note 14A. The thermal head according to supplementary note 13A, further comprising an insulating layer covering the main surface, the first inclined surface, the second inclined surface, and the first glaze layer, the insulating layer being located between the substrate and the wiring layer.

The thermal head according to any one of supplementary notes 15A to 4A, further comprising a protective layer covering the plurality of heat generating portions.

The thermal head according to supplementary note 16A, wherein the wiring layer includes a common wiring that is in conduction with the plurality of heat generating portions and a plurality of individual wirings that are in conduction with the plurality of heat generating portions, respectively.

The thermal head according to supplementary note 17A. The thermal head according to supplementary note 16A, further comprising a heat radiating member located on a side opposite to the first glaze layer with respect to the substrate in the 1 st direction, the substrate being bonded to the heat radiating member.

(embodiment 4)

A thermal head a10 according to embodiment 4 of the present invention will be described with reference to fig. 32 to 41. The thermal head a10 includes a substrate 1, a first glaze layer 21, a resistor layer 3, a wiring layer 4, and a protective layer 5. The thermal head a10 further includes a heat radiating member 72, a plurality of driving elements 73, a sealing resin 76, and a connector 77. Here, for ease of understanding, fig. 35 and 36 omit illustration of the protective layer 5.

The thermal head a10 shown in these figures is an electronic device that performs printing on a recording medium such as thermal paper by selectively generating heat in a plurality of heat generating portions 31 (described in detail later) included in the resistor layer 3. The resistor layer 3 is formed by printing and sintering. Therefore, the thermal head a10 is called a so-called thick film type.

For convenience of explanation, the normal direction of the main surface 11 of the substrate 1 to be described later is referred to as "1 st direction z". The direction orthogonal to the 1 st direction z is referred to as "2 nd direction x". The 2 nd direction x corresponds to the main scanning direction of the thermal head a 10. The direction orthogonal to both the 1 st direction z and the 2 nd direction x is referred to as "3 rd direction y". The 3 rd direction y corresponds to the sub-scanning direction of the thermal head a 10.

As shown in fig. 32 and 33, the substrate 1 extends in the 2 nd direction x. The substrate 1 comprises alumina (Al ₂ O ₃ ). The substrate 1 is a ceramic made of a material containing alumina, a resin binder, and the like. In addition, the material of the substrate 1 may further include a light shielding material. The light shielding material is, for example, carbon (C).

As shown in fig. 37 and 38, the substrate 1 has a main surface 11 and a rear surface 12. The main surface 11 and the back surface 12 face opposite to each other in the 1 st direction z. The main surface 11 is opposite to the first glaze layer 21.

As shown in fig. 37 and 38, the first glaze layer 21 covers at least a part of the substrate 1. In the thermal head a10, the first glaze layer 21 covers the entire main surface 11 of the substrate 1. The first glaze layer 21 is formed by screen printing a paste containing amorphous glass on the main surface 11 of the substrate 1, and then sintering the paste. The amorphous glass is, for example, siO ₂ -BaO-Al ₂ O ₃ SnO-ZnO glass. Thus, the first glaze 21 is transparent or white. The glass transition temperature of the first glaze layer 21 is about 680 ℃.

As shown in fig. 39, the first glaze layer 21 contains a filler 211. As shown in fig. 40, the packing 211 has a hollow portion 211A and a shell portion 211B. The hollow portion 211A is vacuum. The shell portion 211B surrounds the hollow portion 211A. The composition of the shell portion 211B includes silicon dioxide (SiO ₂ ). The particle diameter D of the filler 211 is 0.3 μm or more and 0.5 μm or less. The weight percentage (wt%) of the filler 211 with respect to the first glaze layer 21 is 30% to 80%.

As shown in fig. 36 and 37, the wiring layer 4 is in contact with the resistor layer 3. The wiring layer 4 constitutes a conductive path for energizing the resistor layer 3. In the thermal head a10, the wiring layer 4 is in contact with the first glaze layer 21. The wiring layer 4 includes a common wiring 41 and a plurality of individual wirings 42. The common wiring 41 is electrically connected to the plurality of heat generating portions 31. The plurality of individual wirings 42 are individually connected to the plurality of heat generating portions 31. In the thermal head a10, current flows from the common wiring 41 to the plurality of individual wirings 42 via the plurality of heat generating parts 31. Thus, the common wiring 41 is a positive electrode, and the plurality of individual wirings 42 are negative electrodes. As an example of the material of the wiring layer 4, a resinate paste containing gold (Au) as a main component is given. The wiring layer 4 is formed by screen printing a resin paste on the first glaze layer 21, and then performing photolithography patterning and etching on the paste after firing the paste. An example of the thickness range of the wiring layer 4 is 0.6 μm or more and 1.2 μm or less.

As shown in fig. 35, the common wiring 41 has a base 411 and a plurality of extension portions 412. The base 411 is located on one side in the 3 rd direction y with reference to the resistor layer 3 in the 3 rd direction y. The base 411 extends in the 2 nd direction x and away from the 3 rd direction y.

As shown in fig. 35 and 36, the plurality of extension portions 412 extend in the 3 rd direction y from the base 411 toward the resistor layer 3. The plurality of extension portions 412 are arranged at equal intervals along the 2 nd direction x.

As shown in fig. 35, each of the plurality of individual wirings 42 has a base 421 and an extension 422. The plurality of individual wires 42 are arranged as beams corresponding to the plurality of driving elements 73 on the substrate 1. The plurality of individual wirings 42 individually apply voltages to the plurality of heat generating portions 31.

As shown in fig. 35, the base 421 is located on the opposite side of the base 411 of the common wiring 41 with respect to the resistor layer 3 in the 3 rd direction y. The base 421 of each of the plurality of individual wirings 42 is formed in two rows separated from each other in the 3 rd direction y. Each of the two columns is arranged along the 2 nd direction x. In the column closest to the resistor layer 3 among the two columns, the extension 422 is located between the adjacent two base portions 421.

As shown in fig. 35, the extension 422 is connected to the base 421. The extension 422 also includes a first portion 422A, a second portion 422B, and a third portion 422C.

As shown in fig. 35 and 36, the first portion 422A extends in the 3 rd direction y. The 1 st portions 422A are arranged at equal intervals along the 2 nd direction x. The first portion 422A is located between two extension portions 412 adjacent in the 2 nd direction x among the plurality of extension portions 412 of the common wiring 41.

As shown in fig. 35 and 36, the second portion 422B is connected to the first portion 422A. A majority of the second portions 422B of the respective extension portions 422 of the plurality of individual wirings 42 are inclined with respect to the 3 rd direction y.

As shown in fig. 35 and 36, the third portion 422C is located opposite to the first portion 422A with respect to the second portion 422B in the 3 rd direction y. The third portion 422C is connected to the second portion 422B and the base 411. The third portion 422C extends in the 3 rd direction y.

As shown in fig. 35, when the boundary positions of the second portion 422B and the third portion 422C are compared on both sides in the 2 nd direction x in one bundle of the plurality of individual wirings 42 corresponding to the plurality of driving elements 73, the shift Δl in the 3 rd direction y occurs.

As shown in fig. 32 and 35, the resistor layer 3 extends in the 2 nd direction x. As shown in fig. 36 and 37, the resistor layer 3 is in contact with the first glaze layer 21. The resistor layer 3 intersects the first portions 422A of the respective extending portions 412 of the common wiring 41 and the extending portions 422 of the respective individual wirings 42. The resistor layer 3 covers a portion of the first portion 422A of the extension 422 of each of the plurality of extension portions 412 and each of the plurality of individual wirings 42. In the thermal head a10, the resistor layer 3 spans the plurality of extending portions 412 and the first portions 422A of the extending portions 422 of the respective plurality of individual wirings 42.

The region sandwiched by the portion of the resistor layer 3 covering any one of the plurality of extending portions 412 and the portion covering any one of the first portions 422A of the plurality of individual wires 42 located beside the portion in the 2 nd direction x is any one of the plurality of heat generating portions 31. As shown in fig. 35, the plurality of heat generating portions 31 are arranged along the 2 nd direction x. The plurality of heat generating portions 31 are located on the opposite side of the substrate 1 with respect to the first glaze layer 21 in the 1 st direction z. By selectively energizing the wiring layer 4, the plurality of heat generating portions 31 selectively generate heat. Thereby, dot printing is performed on the recording medium shown in fig. 34. The material of the resistor layer 3 is selected to have a higher resistivity than the material of the wiring layer 4. An example of the material of the resistor layer 3 is a material containing ruthenium oxide (RuO ₂ ) And a particulate and frit electroconductive paste. The resistor layer 3 is formed by screen printing an electroconductive paste on the first glaze layer 21 and then sintering the paste. The maximum thickness of the resistor layer 3 is 6 μm to 10 μm.

As shown in fig. 41, the plurality of heat generating portions 31 overlap the filler 211 of the first glaze layer 21 as viewed in the 1 st direction z.

As shown in fig. 37 and 38, the protective layer 5 is in contact with the first glaze layer 21. The protective layer 5 covers the plurality of heat generating portions 31. The protective layer 5 also covers a part of the wiring layer 4. In the thermal head a10, the wiring layer 4 except for a part of the common wiring 41 connected to the base 411 and the base 421 of each of the plurality of individual wirings 42 is covered with the protective layer 5.

The protective layer 5 is made of a material containing amorphous glass in the same manner as the first glaze layer 21. The protective layer 5 is formed by screen printing a paste containing amorphous glass on a part of the first glaze layer 21, the resistor layer 3, and the wiring layer 4, and then sintering the paste.

As shown in fig. 34, the heat sink 72 is located on the opposite side of the first glaze layer 21 with respect to the substrate 1 in the 1 st direction z. The rear surface 12 of the substrate 1 is bonded to the heat dissipation member 72 via a bonding material (not shown). The composition of the heat dissipation member 72 includes, for example, aluminum (Al).

As shown in fig. 32 and 34, the plurality of driving elements 73 are located on the other side in the 3 rd direction y with respect to the resistor layer 3. The driving element 73 is mounted on the substrate 1. A plurality of electrodes (not shown) are provided on the upper surface of the driving element 73. A plurality of first leads 74 are conductively bonded to some of the plurality of electrodes and are conductively bonded to the bases 421 of the plurality of individual wires 42 corresponding to the drive elements 73. Thereby, the driving element 73 is conducted with the plurality of individual wirings 42 corresponding thereto. A plurality of second leads 75 are connected to the other plurality of pads and electrically connected to the wiring disposed on the substrate 1. The driving element 73 selectively energizes the plurality of individual wires 42 via the plurality of first leads 74. Thereby, the plurality of heat generating portions 31 selectively generate heat. The driving element 73 may be separated from the substrate 1 in the 3 rd direction y and mounted on a wiring board supported by the heat sink 72. The wiring board is, for example, a PCB (Printed Circuit Board ).

As shown in fig. 34, the sealing resin 76 covers the plurality of driving elements 73, the plurality of first leads 74, and the plurality of second leads 75. In addition, the sealing resin 76 covers a part of the area (the plurality of base portions 421 and the like) of the plurality of individual wirings 42 not covered by the protective layer 5. The sealing resin 76 is, for example, a black and soft synthetic resin for the underfill. The sealing resin 76 may be a black and hard synthetic resin.

As shown in fig. 32 to 34, the connector 77 is located on the opposite side of the resistor layer 3 with respect to the plurality of driving elements 73 in the 3 rd direction y. In the thermal head a10, a connector 77 is mounted at an end portion of the substrate 1 in the 3 rd direction y. The connector 77 is connected to a thermal printer. The connector 77 has a plurality of pins (not shown). A part of the plurality of pins is electrically connected to a wiring (not shown) having a plurality of second leads 75 electrically connected thereto on the substrate 1. The other part of the plurality of pins is connected to a wiring (not shown) connected to the base 411 of the common wiring 41 on the substrate 1. Thereby, a constant voltage is applied to the common wiring 41 from the outside via the connector 77.

Next, the operation of the thermal head a10 will be described.

As shown in fig. 34, the plurality of heat generating portions 31 of the thermal head a10 are opposed to the platen roller 79 incorporated in the thermal printer via the protective layer 5. The platen roller 79 is a roller mechanism for feeding out the recording medium. The recording medium is sandwiched between the platen roller 79 and the region of the protective layer 5 covering the plurality of heat generating portions 31. When the thermal printer is operated, the platen roller 79 rotates to feed the recording medium in the 3 rd direction y at a constant speed. At this time, when the plurality of heat generating portions 31 selectively generate heat, the heat is transferred to the recording medium via the protective layer 5, thereby performing printing on the recording medium. At the same time, heat generated from the plurality of heat generating portions 31 is also transferred to the first glaze layer 21. A part of the heat transferred to the first glaze layer 21 is accumulated in the first glaze layer 21. Other heat is released to the outside of the thermal head a10 via the substrate 1 and the heat radiating member 72.

Next, the operational effects of the thermal head a10 will be described.

The first glaze 21 of the thermal print head a10 covers at least a part of the substrate 1. The plurality of heat generating portions 31 of the resistor layer 3 are located on the opposite side of the substrate 1 with respect to the first glaze layer 21 in the 1 st direction z. The first glaze layer 21 contains a filler 211. The packing 211 has a hollow portion 211A. By adopting the present structure, the thermal conductivity of the first glaze layer 21 is further reduced. Therefore, the heat transferred from the plurality of heat generating portions 31 to the first glaze layer 21 stays in the first glaze layer 21 for a longer time, so that the heat storage performance of the first glaze layer 21 is improved. Therefore, according to the present configuration, in the thermal head a10, since the heat storage performance of the glaze layer is improved, an increase in power consumption of the thermal head a10 can be suppressed.

The plurality of heat generating portions 31 overlap the filler 211 as viewed in the 1 st direction z. By adopting this structure, the heat storage property of the first glaze layer 21 can be improved efficiently.

The packing 211 has a shell portion 211B surrounding a hollow portion 211A. The hollow portion 211A is vacuum. By adopting this structure, when the paste containing amorphous glass as the first glaze layer 21 is sintered, the bursting of the filler 211 due to the thermal expansion of the hollow portion 211A can be prevented.

The composition of the shell portion 211B of the filler 211 comprises silica. By adopting this structure, the linear expansion coefficient of the filler 211 is substantially equal to that of the first glaze layer 21. This can reduce the occurrence of thermal stress at the interface between the filler 211 and the first glaze layer 21, and thus can suppress the occurrence of cracks in the first glaze layer 21.

By improving the heat storage performance of the first glaze layer 21, the thickness of the first glaze layer 21 can be made thinner within a range that does not deteriorate the heat storage performance. With this configuration, when screen printing is performed on the main surface 11 with a paste containing amorphous glass as the first glaze layer 21, the surface tension due to an emulsion or the like around the paste is reduced. Thereby, the first glaze layer 21 becomes flatter.

The thermal head a10 further includes a protective layer 5 covering the plurality of heat generating portions 31. By adopting this structure, the frictional resistance between the recording medium and the thermal head a10 can be further reduced.

The thermal head a10 further includes a heat radiation member 72 located on the opposite side of the first glaze 21 with respect to the substrate 1 in the 1 st direction z. The substrate 1 is bonded to the heat dissipation member 72. By adopting this structure, an excessive increase in temperature of the first glaze layer 21 can be suppressed. This can prevent degradation of print quality.

(embodiment 5)

A thermal head a20 according to embodiment 5 of the present invention will be described with reference to fig. 42 to 44. In these drawings, the same or similar elements as those of the thermal head a10 are denoted by the same reference numerals, and redundant description thereof is omitted. Here, for ease of understanding, illustration of the protective layer 5 is omitted in fig. 42.

In the thermal head a20, the structure of the first glaze layer 21 and the second glaze layer 22 are also included, which is different from the case of the thermal head a10 described above.

As shown in fig. 43 and 44, the second glaze layer 22 covers a part of the main surface 11 of the substrate 1. The second glaze layer 22 is formed by screen printing a paste containing a quasi-crystalline (semi-crystalline) glass on the main surface 11 of the substrate 1, and then sintering the paste. The quasicrystal glass is, for example, siO ₂ -B ₂ O ₃ -Al ₂ O ₃ -ZrO ₂ Is glass. Thus, the second glaze 22 is white. The glass transition temperature of the second glaze 22 is about 740 ℃. Thus, the glass transition temperature of the first glaze layer 21 is lower than the glass transition temperature of the second glaze layer 22.

As shown in fig. 42 to 44, the second glaze layer 22 is positioned on both sides of the first glaze layer 21 in the 3 rd direction y. The second glaze 22 has a basal plane 221 facing the opposite side to the side opposite to the substrate 1 in the 1 st direction z. The second glaze layer 22 is formed with an opening 22A penetrating in the 1 st direction z. The opening 22A extends in the 2 nd direction x. The main surface 11 of the substrate 1 is exposed at the opening 22A.

As shown in fig. 43 and 44, at least a part of the first glaze layer 21 is accommodated in the opening 22A of the second glaze layer 22. The first glaze layer 21 is in contact with the main surface 11 of the substrate 1. The base 221 of the second glaze 22 includes a pair of end edges 221A sandwiching the first glaze 21. The first glaze 21 contacts the pair of end edges 221A.

As shown in fig. 43 and 44, in the thermal head a20, the first glaze 21 protrudes from the base 221 of the second glaze 22. The peripheral edge of the portion of the first glaze layer 21 protruding from the base surface 221 is curved in a convex shape as viewed from the 2 nd direction x.

Next, a method of forming the first glaze layer 21 and the second glaze layer 22 in the manufacturing method of the thermal head a20 will be described with reference to fig. 45 and 46. The cross-sectional positions of fig. 45 and 46 are the same as those of fig. 43.

First, as shown in fig. 45, the second glaze layer 22 is formed so as to cover a part of the main surface 11 of the substrate 1. The second glaze layer 22 is formed by screen printing a paste containing a quasicrystal glass on the main surface 11 of the substrate 1 and then sintering the paste. At the time of screen printing, an emulsion or the like is applied to the main surface 11 so that the openings 22A are formed in the second glaze layer 22.

Next, as shown in fig. 46, the first glaze layer 21 is formed. In forming the first glaze layer 21, a paste containing amorphous glass is applied to the openings 22A of the second glaze layer 22 by a dispenser. The paste contains a filler 211. The paste is then sintered. The sintering temperature is adjusted in such a way that the glass transition temperature of the second glaze layer 22 is not exceeded. As described above, the first glaze layer 21 and the second glaze layer 22 are formed.

< modification >

A thermal head a21, which is a modification of the thermal head a20, will be described with reference to fig. 47 and 48. The structure of the first glaze 21 of the thermal head a21 is different from that of the thermal head a 20.

As shown in fig. 47 and 48, the first glaze 21 is flush with the base 221 of the second glaze 22. The thickness of the first glaze layer 21 is equal to the thickness of the second glaze layer 22.

Next, the operational effects of the thermal head a20 will be described.

The first glaze 21 of the thermal print head a20 covers at least a part of the substrate 1. The plurality of heat generating portions 31 of the resistor layer 3 are located on the opposite side of the substrate 1 with respect to the first glaze layer 21 in the 1 st direction z. The first glaze layer 21 contains a filler 211. The packing 211 has a hollow portion 211A. Therefore, according to the present configuration, the thermal storage performance of the glaze layer is also improved in the thermal head a20, so that an increase in power consumption of the thermal head a20 can be suppressed. The thermal head a20 has a structure common to the thermal head a10, and thus exhibits the same operational effects as the thermal head a 10.

In the thermal head a20, a second glaze layer 22 is further included on both sides of the first glaze layer 21 in the 3 rd direction y. The base 221 of the second glaze 22 includes a pair of end edges 221A sandwiching the first glaze 21. The first glaze 21 contacts the pair of end edges 221A. By adopting this structure, the volume of the first glaze layer 21 can be prevented from excessively shrinking. Thus, while ensuring the function of the first glaze layer 21, the material cost of the first glaze layer 21 required for manufacturing the thermal head a20 can be reduced.

In the thermal head a20, the first glaze 21 protrudes from the base 221 of the second glaze 22. Further, the peripheral edge of the portion of the 1 st glaze layer 21 protruding from the base 221 is curved in a convex shape as viewed from the 2 nd direction x. By adopting this configuration, when printing on a recording medium, the contact area between the recording medium and the thermal head a20 can be controlled to the maximum extent, and heat from the plurality of heat generating portions 31 can be transferred to the recording medium. Thereby enabling further improvement in printing quality.

(embodiment 6)

A thermal head a30 according to embodiment 6 of the present invention will be described with reference to fig. 49 to 54. In these drawings, the same or similar elements as those of the thermal head a10 are denoted by the same reference numerals, and redundant description thereof is omitted.

The thermal head a30 is composed of a main portion and an accessory portion. The main portion of the thermal head a30 includes a substrate 1, an insulating layer 23, a resistor layer 3, a wiring layer 4, and a protective layer 5. The thermal head a30 includes a wiring board 71, a heat radiating member 72, a plurality of driving elements 73, a plurality of first leads 74, a plurality of second leads 75, a sealing resin 76, and a connector 77. Here, in fig. 49, for ease of understanding, the protective layer 5, the plurality of first leads 74, the plurality of second leads 75, and the sealing resin 76 are omitted from illustration. In fig. 50 and 51, the protective layer 5 is omitted for ease of understanding.

In the thermal head a30, as shown in fig. 52, the substrate 1 constituting a main portion of the thermal head a30 is joined to the heat radiating member 72. Further, the wiring board 71 is located beside the board 1 in the 3 rd direction y. The wiring board 71 is bonded to the heat dissipation member 72 in the same manner as the board 1. A plurality of heat generating portions 31, which form part of the resistor layer 3 and are arranged in the 2 nd direction x, are formed on the substrate 1. The plurality of heat generating portions 31 selectively generate heat in accordance with the plurality of driving elements 73 mounted on the wiring board 71. The plurality of driving elements 73 are driven in accordance with a print signal transmitted from the outside via the connector 77.

As shown in fig. 49, the substrate 1 has a rectangular shape extending in the 2 nd direction x as viewed in the 1 st direction z. The substrate 1 comprises a semiconductor material. The semiconductor material includes a single crystal material composed of silicon (Si).

As shown in fig. 52, in the thermal head a30, the main surface 11 is opposed to the platen roller 79, and the back surface 12 is opposed to the heat radiation member 72. The plane orientation of the main surface 11 based on the crystal structure of the substrate 1 is a (100) plane.

As shown in fig. 53, the substrate 1 has the convex portion 13. The convex portion 13 protrudes from the main surface 11 in the 1 st direction z. As shown in fig. 49 and 50, the convex portion 13 extends in the 2 nd direction x. The convex portion 13 is formed by performing anisotropic etching using a potassium hydroxide (KOH) solution on the substrate 1.

As shown in fig. 53 and 54, the convex portion 13 has a top surface 130, a first inclined surface 131, and a second inclined surface 132. The top surface 130, the first inclined surface 131, and the second inclined surface 132 extend in the 2 nd direction x. The top surface 130 faces in the 1 st direction z and is located away from the main surface 11. The first inclined surface 131 and the second inclined surface 132 are located between the main surface 11 and the top surface 130. In the thermal head a30, the first inclined surface 131 and the second inclined surface 132 are connected to the main surface 11 and the top surface 130. The first inclined surface 131 and the second inclined surface 132 are located at positions separated from each other in the 3 rd direction y. The first inclined surface 131 and the second inclined surface 132 are inclined with respect to the main surface 11. The first inclined surface 131 and the second inclined surface 132 approach each other as going from the main surface 11 to the top surface 130. The first inclined surface 131 and the second inclined surface 132 have the same inclination angle α with respect to the main surface 11.

The first glaze 21 covers the top surface 130 of the protrusion 13. The peripheral edge of the portion of the first glaze layer 21 on the side where the plurality of heat generating portions 31 are located in the 1 st direction z as viewed from the 2 nd direction x is curved in a convex shape.

As shown in fig. 53 and 54, the insulating layer 23 covers the main surface 11 of the substrate 1, the first inclined surface 131 and the second inclined surface 132 of the convex portion 13, and the first glaze layer 21. The insulating layer 23 is located between the substrate 1 and the wiring layer 4. The substrate 1 is electrically insulated from the resistor layer 3 and the wiring layer 4 by the insulating layer 23. The insulating layer 23 is made of, for example, silicon dioxide using tetraethyl orthosilicate (TEOS) as a raw material. The thickness of the insulating layer 23 is, for example, 1 μm or more and 15 μm or less. The thermal conductivity of the insulating layer 23 is higher than that of the first glaze layer 21.

As shown in fig. 53 and 54, the resistor layer 3 is disposed on the main surface 11 and the convex portion 13 of the substrate 1. The resistor layer 3 is in contact with the insulating layer 23. Thus, in the thermal head a30, the insulating layer 23 is sandwiched between the substrate 1 and the resistor layer 3. The resistor layer 3 is made of tantalum nitride (TaN), for example. The thickness of the resistor layer 3 is, for example, 0.02 μm or more and 0.1 μm or less.

As shown in fig. 50, 51, and 54, the resistor layer 3 includes a plurality of heat generating portions 31. In the resistor layer 3, the plurality of heat generating portions 31 are exposed from the wiring layer 4. By selectively energizing the plurality of heat generating portions 31 from the wiring layer 4, the plurality of heat generating portions 31 locally heat the recording medium. The plurality of heat generating portions 31 are arranged along the 2 nd direction x. Of the plurality of heat generating portions 31, two heat generating portions 31 adjacent in the 2 nd direction x are located at positions apart from each other. The plurality of heat generating portions 31 are formed so as to be in contact with the insulating layer 23. In the thermal head a30, a plurality of heat generating portions 31 are formed on the top surface 130 of the convex portion 13 of the substrate 1. The plurality of heat generating portions 31 are located at the center of the top surface 130 in the 3 rd direction y. As shown in fig. 52, the plurality of heat generating portions 31 are opposed to the platen roller 79.

As shown in fig. 53 and 54, the wiring layer 4 is disposed so as to be in contact with the resistor layer 3. The wiring layer 4 is electrically connected to the plurality of heat generating portions 31 of the resistor layer 3. The resistivity of the wiring layer 4 is lower than the resistivity of the resistor layer 3. The wiring layer 4 is, for example, a metal layer made of copper (Cu). The thickness of the wiring layer 4 is, for example, 0.3 μm or more and 2.0 μm or less. The wiring layer 4 may be composed of two metal layers, i.e., a titanium (Ti) layer laminated on the resistor layer 3 and a copper layer laminated on the Ti layer. The thickness of the titanium layer in this case is, for example, 0.1 μm or more and 0.2 μm or less. As shown in fig. 49, the wiring layer 4 is located at a position apart from the peripheral edge of the main surface 11 of the substrate 1.

As shown in fig. 49, the wiring layer 4 includes a common wiring 41 and a plurality of individual wirings 42. The common wiring 41 is located on the opposite side of the plurality of driving elements 73 with respect to the plurality of heat generating portions 31 of the resistor layer 3 in the 3 rd direction y. The plurality of individual wirings 42 are located on the opposite side of the common wiring 41 with respect to the plurality of heat generating portions 31 in the 3 rd direction y. The common wiring 41 is electrically connected to the plurality of heat generating portions 31. The plurality of individual wirings 42 are individually conducted to the plurality of heat generating portions 31.

As shown in fig. 50 and 51, the common wiring 41 has a base 411 and a plurality of extension portions 412 connected to the base 411. The base 411 is located on the opposite side of the plurality of heat generating portions 31 of the resistor layer 3 with respect to the plurality of extension portions 412 in the 3 rd direction y. The base 411 is a band-like shape extending in the 2 nd direction x. The plurality of extending portions 412 are band-shaped extending in the 3 rd direction y from the end of the base 411 facing the convex portion 13 of the substrate 1 toward the plurality of heat generating portions 31. The plurality of extensions 412 are aligned along the 2 nd direction x. A portion of each of the plurality of extension portions 412 is located above the second inclined surface 132 of the convex portion 13. In the common wiring 41, current flows from the base 411 to the plurality of heat generating portions 31 via the plurality of extension portions 412.

As shown in fig. 50 and 51, each of the plurality of individual wirings 42 has a base 421 and an extension 422 connected to the base 421. The base 421 is located on the opposite side of the plurality of heat generating portions 31 of the resistor layer 3 with respect to the extension 422 in the 3 rd direction y. The base portions 421 of the plurality of individual wirings 42 are formed in two rows separated from each other in the 3 rd direction y. The two columns are each aligned along the 2 nd direction x. In the column closest to the plurality of heat generating portions 31 among the two columns, the extension portion 422 is located between the adjacent two base portions 421.

As shown in fig. 50 and 51, the extension portion 422 is a band-like portion extending in the 3 rd direction y from the end portion of the base 421 facing the convex portion 13 of the substrate 1 toward the plurality of heat generating portions 31. The extension portions 422 of the respective individual wirings 42 are arranged in the 2 nd direction x. A part of the extension 422 of each of the plurality of individual wirings 42 is located above the first inclined surface 131 of the convex portion 13. In each of the plurality of individual wirings 42, current flows from any one of the plurality of heat generating portions 31 to the base 421 via the extension portion 422. The plurality of heat generating portions 31 are sandwiched between the extending portion 422 of any one of the plurality of individual wires 42 and any one of the plurality of extending portions 412 of the common wire 41, respectively, as viewed in the 1 st direction z. The configuration of the wiring layer 4 and the plurality of heat generating portions 31 shown in fig. 50 and 51 is an example. Therefore, the configuration of the wiring layer 4 and the plurality of heat generating portions 31 in the present invention is not limited to the configuration shown in fig. 50 and 51.

As shown in fig. 53, the protective layer 5 covers a part of the insulating layer 23, the plurality of heat generating portions 31 of the resistor layer 3, and the wiring layer 4. The protective layer 5 has electrical insulation. The composition of the protective layer 5 comprises silicon. The protective layer 5 is made of, for example, silicon dioxide and silicon nitride (Si ₃ N ₄ ) Any one of them. Alternatively, the protective layer 5 may be a laminate composed of a plurality of these materials. The recording medium is pressed by the platen roller 79 shown in fig. 52 at a portion of the protective layer 5 covering the plurality of heat generating portions 31.

As shown in fig. 53, the protective layer 5 has a wiring opening 5A. The wiring opening 5A penetrates the protective layer 5 in the 1 st direction z. A portion of the base 421 of each of the plurality of individual wires 42 and a portion of the extension 422 of each of the plurality of individual wires 42 are exposed from the wire opening 5A.

As shown in fig. 52, the wiring board 71 is located beside the board 1 in the 3 rd direction y. As shown in fig. 49, the plurality of individual wires 42 are located between the plurality of heat generating portions 31 of the resistor layer 3 and the wiring board 71 in the 3 rd direction y as seen in the 1 st direction z. The area of the wiring substrate 71 is larger than the area of the substrate 1 as viewed in the 1 st direction z. The wiring board 71 has a rectangular shape with the 2 nd direction x as the longitudinal direction when viewed in the 1 st direction z. The wiring board 71 is, for example, a PCB board. A plurality of driving elements 73 and connectors 77 are mounted on the wiring board 71.

As shown in fig. 52, the heat sink 72 is opposed to the back surface 12 of the substrate 1. The back side 12 is engaged with the heat sink member 72. The wiring board 71 is joined to the heat dissipation member 72 by a fastening member such as a screw. When the thermal head a30 is used, a part of heat generated from the plurality of heat generating portions 31 of the resistor layer 3 is conducted to the heat radiating member 72 via the substrate 1. The heat conducted to the heat radiating member 72 radiates heat to the outside. The heat sink 72 is made of aluminum (Al), for example.

As shown in fig. 49 and 52, the plurality of driving elements 73 are mounted on the wiring board 71 via a die bonding material (not shown) having electrical insulation properties. The plurality of driving elements 73 are semiconductor elements constituting various circuits. One ends of a plurality of first leads 74 and one ends of a plurality of second leads 75 are conductively bonded to the plurality of driving elements 73. The other ends of the plurality of first leads 74 are individually conductively bonded to the respective bases 421 of the plurality of individual wires 42. The other ends of the plurality of second leads 75 are provided on the wiring board 71 and are electrically connected to wiring (not shown) that is electrically connected to the connector 77.

As described above, the electric signal related to printing and the electric signal related to control of the plurality of driving elements 73 are input into the plurality of driving elements 73 from the outside via the connector 77. The plurality of driving elements 73 selectively apply voltages to the plurality of individual wirings 42 based on these electrical signals. Further, a constant voltage is applied to the common wiring 41 from the outside via the connector 77. In this case, a potential difference is generated between the common wiring 41 and any one of the plurality of individual wirings 42, whereby the plurality of heat generating portions 31 of the resistor layer 3 selectively generate heat.

As shown in fig. 52, the sealing resin 76 covers the plurality of driving elements 73, the plurality of first leads 74, and the plurality of second leads 75. The sealing resin 76 also covers a part of each of the insulating layer 23 and the wiring board 71, and a part of each of the plurality of individual wirings 42.

As shown in fig. 49 and 52, the connector 77 is mounted on the end portion of the wiring board 71 in the 3 rd direction y. The connector 77 has a plurality of pins (not shown). A part of the plurality of pins is electrically connected to a wiring (not shown) electrically connected to the plurality of second leads 75 in the wiring board 71. The other portions of the plurality of pins are electrically connected to wiring (not shown) electrically connected to the base 411 of the common wiring 41 in the wiring board 71.

Next, the operational effects of the thermal head a30 will be described.

The first glaze 21 of the thermal print head a30 covers at least a part of the substrate 1. The plurality of heat generating portions 31 of the resistor layer 3 are located on the opposite side of the substrate 1 with respect to the first glaze layer 21 in the 1 st direction z. The first glaze layer 21 contains a filler 211. The packing 211 has a hollow portion 211A. Therefore, according to the present configuration, the thermal storage performance of the glaze layer in the thermal head a30 is also improved, so that an increase in power consumption of the thermal head a30 can be suppressed. The thermal head a30 has a structure common to the thermal head a10, and thus exhibits the same operational effects as the thermal head a 10.

In the thermal head a30, the substrate 1 has a convex portion 13 protruding from the main surface 11 in the 1 st direction z. The first glaze 21 covers the top surface 130 of the protrusion 13. By adopting this structure, the plurality of heat generating portions 31 are located above the convex portion 13. Thus, when printing on the recording medium, the contact area between the recording medium and the thermal head a30 can be minimized, and heat from the plurality of heat generating portions 31 can be transferred to the recording medium. Therefore, the printing quality of the recording medium can be improved.

The thermal head a30 further includes an insulating layer 23 covering the main surface 11 of the substrate 1, the first and second inclined surfaces 131 and 132 of the convex portion 13, and the first glaze layer 21. The insulating layer 23 is located between the substrate 1 and the wiring layer 4. By adopting this structure, even if the substrate 1 contains a semiconductor material, electrical insulation between the substrate 1 and the resistor layer 3 and the wiring layer 4 can be achieved. Further, by setting the thermal conductivity of the insulating layer 23 to be higher than that of the first glaze layer 21, loss of heat conducted from the plurality of heat generating portions 31 to the first glaze layer 21 can be suppressed.

(embodiment 7)

A thermal head a40 according to embodiment 7 of the present invention will be described with reference to fig. 55 to 59. In these drawings, the same or similar elements as those of the thermal head a10 are denoted by the same reference numerals, and redundant description thereof is omitted. Here, for ease of understanding, fig. 55 omits illustration of the first protective layer 51 and the second protective layer 52 described later and the protective member 45 of the wiring layer 4 described later.

The thermal head a40 differs from the thermal head a30 described above in that the substrate 1 and the wiring layer 4 have a first protective layer 51 and a second protective layer 52 instead of the protective layer 5, and do not include the insulating layer 23. The thermal head a40 is a so-called thin film type.

The substrate 1 includes, for example, alN (aluminum nitride) or Al ₂ O ₃ (alumina) and the like. Therefore, the substrate 1 has electrical insulation.

As shown in fig. 55 to 57, the first glaze layer 21 is in contact with the main surface 11 of the substrate 1. The first glaze layer 21 extends in the x-direction and bulges in the z-direction in a cross section with the y-direction and the z-direction as in-plane directions. The first glaze layer 21 may be formed on the entire main surface 11 as in the structure of the thermal head a 10.

As shown in fig. 55, the common wiring 41 has a detour 413 in addition to the base 411 and the extension 412. The detour 413 is connected to one side of the base 411 in the x direction, and extends from the base 411 to the side where the plurality of individual wirings 42 are located in the y direction.

As shown in fig. 55, the wiring layer 4 includes a ground portion 43. The grounding portion 43 has a rectangular shape as viewed in the z direction. The ground portion 43 is located between the detour portion 413 of the common wiring 41 and the plurality of individual wirings 42 in the y-direction. The ground portion 43 is electrically connected to a ground terminal disposed inside the connector 77. As shown in fig. 57, the grounding portion 43 includes a connection portion 431 and an extension portion 432. The connection portion 431 has the same composition as the common wiring 41 and the plurality of individual wirings 42. The composition of the extension 432 is the same as that of the resistor layer 3. As shown in fig. 59, one end of the first lead 74 is connected to the connection portion 431, and the other end of the first lead 74 is connected to the second wiring 712 disposed on the main surface 11 of the substrate 1. The second wiring 712 is conducted to a ground terminal located inside the connector 77. The extension portion 432 extends from the connection portion 431 toward the side where the plurality of heat generating portions 31 of the resistor layer 3 are located in the y-direction as viewed in the z-direction.

As shown in fig. 56 and 57, the first protective layer 51 covers a part of the main surface 11 of the substrate 1, the plurality of heat generating portions 31 of the resistor layer 3, and the wiring layer 4. The first protective layer 51 has electrical insulation. The composition of the first protective layer 51 contains silicon. The first protective layer 51 is made of, for example, any one of silicon dioxide and silicon nitride. Alternatively, the first protective layer 51 may be a laminate composed of a plurality of these materials. The recording medium is overlapped with the area of the first protective layer 51 covering the plurality of heat generating portions 31 by the platen roller 79.

As shown in fig. 58 and 59, the second protective layer 52 covers the first protective layer 51. The second protective layer 52 has conductivity. The second protective layer 52 is made of a material containing, for example, C/SiC (a compact formed by mixing carbon and silicon carbide). The recording medium is pressed against the second protective layer 52 by the platen roller 79 shown in fig. 56 and 57.

As shown in fig. 55, the wiring layer 4 includes a conductive member 44. As shown in fig. 58, the conductive member 44 is electrically connected to the connection portion 431 of the ground portion 43 and the second protective layer 52. The conductive member 44 is in contact with an end face of the first protective layer 51. The conductive member 44 is made of, for example, a material containing a resin containing silver particles.

As shown in fig. 56, the wiring layer 4 includes a protective member 45. The protective member 45 covers the conductive member 44. The protective member 45 has electrical insulation. The protective member 45 is made of a material containing a resin, for example. Further, the protection member 45 covers the extension portion 432 of the ground portion 43 and a part of each of the plurality of individual wirings 42.

As shown in fig. 55, the plurality of individual wirings 42 are conducted with the plurality of first wirings 711 via the plurality of first leads 74, the plurality of driving elements 73, and the plurality of second leads 75. The plurality of first wirings 711 are disposed on the main surface 11 of the substrate 1. The plurality of first wirings 711 are conductive to the connector 77.

Next, the operational effects of the thermal head a40 will be described.

The first glaze 21 of the thermal print head a40 covers at least a part of the substrate 1. The plurality of heat generating portions 31 of the resistor layer 3 are located on the opposite side of the substrate 1 with respect to the first glaze layer 21 in the 1 st direction z. The first glaze layer 21 contains a filler 211. The packing 211 has a hollow portion 211A. Therefore, according to the present configuration, the thermal storage performance of the glaze layer is also improved in the thermal head a40, so that an increase in power consumption of the thermal head a40 can be suppressed. The thermal head a40 has a structure common to the thermal head a10, and thus exhibits the same operational effects as the thermal head a 10.

In the thermal head a40, the second protective layer 52 has conductivity. The wiring layer 4 includes a ground portion 43 and a conductive member 44 that is electrically connected to the ground portion 43 and the conductive member 44. With this configuration, when the thermal head a40 is used, static electricity charged in the first protective layer 51 and the second protective layer 52 in response to contact of the recording medium can be swiftly discharged to the outside through the conductive member 44 and the grounding portion 43. Therefore, the thermal head a40 can be prevented from being electrostatically destroyed.

The present invention is not limited to the above-described embodiments. The specific structure of each part of the present invention can be freely changed in various designs.

Description of symbols

(description of the symbols of the 4 th to 7 th embodiments)

A10, a20, a30, a40: a thermal print head is provided with a plurality of thermal print heads,

1: substrate, 11: major face, 12: the back surface of the back plate is provided with a plurality of grooves,

13: convex part, 130: top surface, 131: a first inclined surface of the first plate,

132: second inclined surface, 21: the first layer of the glaze material is formed by a first layer of the glaze material,

211: filler, 211A: the hollow part is provided with a hollow part,

211B: a shell portion 22: the second layer of the glaze material is arranged on the surface of the first layer of the glaze material,

22A: openings, 221: base, 221A: the end edges of the two end faces are provided with a plurality of grooves,

23: insulating layer, 3: resistor layer, 31: a heating part, a heating part and a heating part,

4: wiring layer, 41: common wiring, 411: the base portion is provided with a plurality of grooves,

412: extension, 413: roundabout portion, 42: the individual wires are arranged in a row,

421: base, 422: extension, 422A: the first portion of the first tube,

422B: second portion, 422C: third section, 43: the grounding part is provided with a plurality of grounding parts,

431: connection part, 432: extension, 44: the conductive members are arranged in a pattern such that,

45: protection component, 5: protective layer, 5A: the wiring openings are provided with a plurality of openings,

51: first protective layer, 52: second protective layer, 71: a wiring board having a plurality of wiring boards,

711: first wiring, 712: second wiring, 72: the heat-dissipating component is provided with a heat-dissipating member,

73: drive element, 74: first lead, 75: a second lead wire is provided with a second lead,

76: sealing resin, 77: connector, 79: the platen roller is provided with a plurality of rollers,

and z: direction 1, x: direction 2, y: direction 3.

Claims (20)

1. A laminate, comprising:

an insulator having a main surface with a linear first concave portion; and

and a heat storage layer which is in contact with a corner formed by the intersection of the main surface and the side surface of the first concave portion, and at least a part of which is disposed at a position higher than the height of the main surface.

2. The laminate of claim 1,

a linear end portion of the heat storage layer is formed along the corner portion of the insulator.

3. The laminate of claim 1 or 2,

the arithmetic average roughness of the bottom surface of the first concave portion is larger than the arithmetic average roughness of the main surface.

4. The laminate according to claim 1 to 3,

the remaining part of the heat storage layer has a portion disposed inside the first recess.

5. The laminate according to any one of claim 1 to 4,

the main surface further has a linear second concave portion extending parallel to the first concave portion,

the heat storage layer is disposed above the main surface between the first recess and the second recess.

6. The laminate according to any one of claim 1 to 5,

in a cross section of the heat storage layer perpendicular to the main surface,

the heat storage layer has a tapered portion above the main surface.

7. The laminate according to any one of claim 1 to 6,

the insulator is a substrate.

8. The laminate of claim 7,

the substrate is made of any one selected from ceramics and silicon.

9. A thermal printhead, comprising:

the laminate of any one of claims 1 to 8;

a heating resistor disposed on the heat storage layer of the laminate;

a separate electrode electrically connected to the heating resistor; and

a common electrode electrically connected to the heating resistor,

the individual electrodes are spaced apart from and opposite to the common electrode.

10. A thermal printer is characterized in that,

a thermal printhead comprising the device of claim 9.

11. A method for forming a heat storage layer is characterized in that,

roughening the main surface of the insulator to form a linear first concave portion,

the heat storage layer paste is applied so as to contact the corner formed by the intersection of the side surface of the first concave portion and the main surface,

The heat storage layer is formed by drying and sintering the heat storage layer paste,

at least a part of the heat storage layer is disposed at a position higher than the height of the main surface.

12. The method of forming a heat storage layer according to claim 11, wherein,

and forming a linear end portion of the heat storage layer along the corner portion of the insulator.

13. The method for forming a heat storage layer according to claim 11 or 12, wherein,

the roughening treatment is performed by wet spraying.

14. The method for forming a heat storage layer according to any one of claim 11 to 13, wherein,

the first recess is formed by removing a part of the insulator by a cutter and roughening the removed insulator.

15. The method for forming a heat storage layer according to any one of claim 11 to 14, wherein,

in the step of coating the heat-storage-layer paste, the heat-storage-layer paste is disposed inside the first recess.

16. The method for forming a heat storage layer according to any one of claim 11 to 15, wherein,

roughening the main surface to form a linear second concave portion extending parallel to the first concave portion,

In the step of applying the heat-storage-layer paste, the heat-storage-layer paste is applied above the main surface between the first concave portion and the second concave portion.

17. The method for forming a heat storage layer according to any one of claims 11 to 16, wherein,

in a cross section of the heat storage layer perpendicular to the main surface,

the heat storage layer has a tapered portion above the main surface.

18. The method for forming a heat storage layer according to any one of claim 11 to 17, wherein,

the insulator is a substrate.

19. The method of forming a heat storage layer according to claim 18, wherein,

the substrate is made of any one selected from ceramics and silicon.

20. A method for manufacturing a thermal head, characterized in that,

the heat storage layer is formed using the method for forming a heat storage layer according to any one of claims 11 to 19,

a heating resistor is formed on the heat storage layer,

forming a separate electrode electrically connected with the heating resistor,

forming a common electrode electrically connected with the heating resistor,

the individual electrodes are formed in a spaced and opposed manner from the common electrode.

Images