JP2022059849A - Thermal print head and method for manufacture thereof and thermal printer - Google Patents

Abstract

To provide a thermal print head which suppresses disconnection of a comb tooth part of a common electrode and a method for manufacture of the thermal print head, and further, provide a thermal printer comprising the thermal print head.SOLUTION: A thermal print head comprises: an individual electrode on a heat accumulation layer; a common electrode having a comb tooth part which is separated from the individual electrode, and faces the individual electrode; a heat element on the individual electrode and the comb tooth part; a connection electrode which comprises a material different from that of the common electrode, and contacts the common electrode; a first protective film which covers a part of the common electrode and wiring; and a second protective film which covers the connection electrode. An end of the common electrode in a sub-scanning direction is covered with the connection electrode, one of lateral faces of the connection electrode in the sub-scanning direction contacts the second protective film, and the other contacts the first protective film.SELECTED DRAWING: Figure 1

Description

The present embodiment relates to a thermal print head, a method for manufacturing the same, and a thermal printer.

The thermal print head includes, for example, a large number of heat generating portions arranged in the main scanning direction on the head substrate. Each heat generating portion is formed by laminating a common electrode and an individual electrode with their ends facing each other so as to expose a part of the resistor layer formed on the head substrate via a glaze layer. Has been done. By energizing between the common electrode and the individual electrodes, the exposed portion (heat generating portion) of the resistor layer generates heat due to Joule heat. By transferring the heat to a printing medium (bar code sheet, thermal paper for producing a receipt, etc.), printing is performed on the printing medium.

The common electrode, the individual electrode, and the like are formed with an electrode pattern by screen-printing a paste using a metal such as gold.

In addition, the connection electrode and wiring for supplying voltage from the outside to the common electrode and individual electrode are in contact with the common electrode and individual electrode, respectively, and the connection electrode is an electrode by screen printing a paste using a metal such as silver. The pattern is formed, and the wiring is formed by a lithography process using a metal such as gold or silver. Gold is expensive, and from the viewpoint of reducing the cost of products, a technique using silver as a relatively inexpensive metal having good electrical conductivity has been proposed.

Japanese Unexamined Patent Publication No. 2000-141729 Japanese Unexamined Patent Publication No. 5-89716

However, when the material of the common electrode and the material of the connection electrode are dissimilar metals, a galvanic phenomenon occurs in which the interface between the common electrode, the connection electrode, and the interface moves due to heating. For example, when the common electrode is made of gold and the connection electrode is made of silver, the silver, which is the material of the connection electrode, is diffused to the common electrode by heating. Due to the diffusion, kerkendal voids are generated on the common electrode, and when the kerkendal voids are generated on the comb tooth portion of the common electrode, the comb tooth portion is a thin electrode and may lead to disconnection. In addition, the diffusion of silver reduces the stretchability of gold, which is the material of the common electrode, and the comb teeth are tensioned by heating, which may induce disconnection.

One aspect of the present embodiment provides a thermal print head that suppresses disconnection of the comb tooth portion of the common electrode. Further, another aspect of the present embodiment provides a method for manufacturing the thermal print head. Further, another aspect of the present embodiment provides a thermal printer provided with the thermal printhead.

In this embodiment, after forming a first protective film covering a heat generating resistor, an individual electrode, a part of a common electrode, and a wiring in contact with the individual electrode, a connection electrode in contact with the common electrode is formed. By doing so, the end of the common electrode in the sub-scanning direction is covered with the connecting electrode, one of the side surfaces of the connecting electrode in the sub-scanning direction is in contact with the second protective film, and the other side of the connecting electrode is the second. It is in contact with the protective film of 1. With this configuration, the path through which the material of the connecting electrode diffuses toward the comb tooth portion of the common electrode can be narrowed, and the diffusion region can be suppressed from reaching the comb tooth portion. Therefore, it is possible to suppress the disconnection of the comb tooth portion of the common electrode. One aspect of this embodiment is as follows.

One embodiment of the present embodiment includes a heat storage layer, an individual electrode on the heat storage layer, a common electrode having a comb tooth portion separated from the individual electrode and facing the individual electrode, and the individual electrode. And the heat-generating resistor on the comb tooth portion, the connection electrode made of a material different from the common electrode and in contact with the common electrode, the heat-generating resistor, the individual electrode, and a part of the common electrode are covered. A first protective film and a second protective film covering the connection electrode are provided, and the end portion of the common electrode in the sub-scanning direction is covered with the connection electrode to cover the connection electrode. One of the side surfaces of the connecting electrode is in contact with the second protective film, and the other side of the connecting electrode is in contact with the first protective film, which is a thermal print head.

Further, another aspect of the present embodiment is a thermal printer provided with the thermal print head.

Further, in another aspect of the present embodiment, a heat storage layer is formed, an individual electrode and a common electrode having a comb tooth portion are formed on the heat storage layer, and a wiring in contact with the individual electrode is formed, and the individual electrode is formed. A heat-generating resistor is formed on the electrode and the common electrode to form a first protective film covering the heat-generating resistor, the individual electrode, a part of the common electrode, and the wiring, and the first protection is formed. After the formation of the film, a connection electrode in contact with the other part of the common electrode is formed, a second protective film covering the connection electrode is formed, and the individual electrode is separated from the comb tooth portion of the common electrode. Moreover, the common electrode is a method for manufacturing a thermal print head, which is opposed to the comb tooth portion and is made of a material different from that of the connection electrode.

According to the present embodiment, it is possible to provide a thermal print head in which disconnection of the comb tooth portion of the common electrode is suppressed. Further, it is possible to provide a method for manufacturing the thermal print head. Further, it is possible to provide a thermal printer provided with the thermal print head.

FIG. 1 is a plan view illustrating the thermal print head 100A according to the present embodiment. FIG. 2 is a cross-sectional view taken along the line AA of FIG. FIG. 3 is a plan view illustrating a method of manufacturing the thermal print head 100A according to the present embodiment (No. 1). FIG. 4 is a cross-sectional view taken along the line AA of FIG. FIG. 5 is a plan view illustrating a method of manufacturing the thermal print head 100A according to the present embodiment (No. 2). FIG. 6 is a cross-sectional view taken along the line AA of FIG. FIG. 7 is a plan view illustrating a method of manufacturing the thermal print head 100A according to the present embodiment (No. 3). FIG. 8 is a cross-sectional view taken along the line AA of FIG. FIG. 9 is a plan view illustrating a method of manufacturing the thermal print head 100A according to the present embodiment (No. 4). FIG. 10 is a cross-sectional view taken along the line AA of FIG. FIG. 11 is a plan view illustrating a method of manufacturing the thermal print head 100A according to the present embodiment (No. 5). FIG. 12 is a cross-sectional view taken along the line AA of FIG. FIG. 13 is a plan view illustrating a method of manufacturing the thermal print head 100A according to the present embodiment (No. 6). FIG. 14 is a cross-sectional view taken along the line AA of FIG. FIG. 15 is a plan view illustrating a method of manufacturing the thermal print head 100A according to the present embodiment (No. 7). FIG. 16 is a cross-sectional view taken along the line AA of FIG. FIG. 17 is a cross-sectional view illustrating the thermal print head 100B according to the present embodiment. FIG. 18 is a cross-sectional view illustrating the thermal print head 100C according to the embodiment. FIG. 19 is a cross-sectional view illustrating the thermal print head 100D according to the embodiment. FIG. 20 is a cross-sectional view illustrating the thermal print head according to the present embodiment.

Next, the present embodiment will be described with reference to the drawings. In the description of the drawings described below, the same or similar parts are designated by the same or similar reference numerals. However, it should be noted that the drawings are schematic and the relationship between the thickness of each component and the plane dimensions is different from the actual one. Therefore, the specific thickness and dimensions should be determined in consideration of the following explanation. In addition, it goes without saying that parts of the drawings having different dimensional relationships and ratios are included.

Further, the embodiments shown below exemplify devices and methods for embodying the technical idea, and do not specify the material, shape, structure, arrangement, etc. of each component. This embodiment can be modified in various ways within the scope of the claims.

A specific embodiment of the present embodiment is as follows.

<1> A heat storage layer, an individual electrode on the heat storage layer, a common electrode having a comb tooth portion separated from the individual electrode and facing the individual electrode, the individual electrode, and the comb tooth portion. A first heat-generating resistor made of a material different from that of the common electrode and covering a connection electrode in contact with the common electrode, the heat-generating resistor, the individual electrode, and a part of the common electrode. A protective film and a second protective film covering the connection electrode are provided, and the end portion of the common electrode in the sub-scanning direction is covered with the connection electrode, and the side surface of the connection electrode in the sub-scanning direction is covered. A thermal print head in which one is in contact with the second protective film and the other side surface of the connection electrode is in contact with the first protective film.

<2> The thermal printhead according to <1>, wherein the common electrode contains gold and the connection electrode contains silver.

<3> The thermal print head according to <1> or <2>, further comprising wiring in contact with the individual electrodes, wherein the connection electrodes are thicker than the wiring.

<4> The item according to any one of <1> to <3>, wherein the connecting electrode has a protruding portion, and the protruding portion is in contact with at least a part of the upper surface of the first protective film. Thermal print head.

<5> The thermal print head according to any one of <1> to <4>, wherein the second protective film covers the first protective film.

<6> The thermal print head according to any one of <1> to <5>, wherein the second protective film is in contact with the upper surface of the first protective film and the upper surface of the connection electrode.

<7> The thermal print head according to any one of <1> to <6>, wherein the individual electrodes are separated from the comb tooth portion in the main scanning direction.

<8> A thermal printer including the thermal print head according to any one of <1> to <7>.

<9> A heat storage layer is formed, an individual electrode and a common electrode having a comb tooth portion are formed on the heat storage layer, a wiring in contact with the individual electrode is formed, and heat is generated on the individual electrode and the common electrode. A resistor is formed, the heat-generating resistor, the individual electrode, a part of the common electrode, and a first protective film covering the wiring are formed, and after the formation of the first protective film, the common electrode is formed. A connection electrode in contact with the other part is formed, a second protective film covering the connection electrode is formed, and the individual electrode is separated from the comb tooth portion of the common electrode and faces the comb tooth portion. A method for manufacturing a thermal print head, wherein the common electrode is made of a material different from that of the connection electrode.

<10> The end of the common electrode in the sub-scanning direction is covered with the connection electrode, and one of the side surfaces of the connection electrode in the sub-scanning direction is in contact with the second protective film, and the side surface of the connection electrode is in contact with the second protective film. The other is the method for manufacturing a thermal print head according to <9>, which is in contact with the first protective film.

<11> The method for manufacturing a thermal printhead according to <9> or <10>, wherein the common electrode contains gold and the connection electrode contains silver.

<12> The method for manufacturing a thermal print head according to any one of <9> to <11>, wherein the connection electrode is thicker than the wiring.

<13> The item according to any one of <9> to <12>, wherein the connecting electrode has a protruding portion, and the protruding portion is in contact with at least a part of the upper surface of the first protective film. How to make a thermal print head.

<14> The method for manufacturing a thermal print head according to any one of <9> to <13>, wherein the second protective film covers the first protective film.

<15> The manufacture of the thermal printhead according to any one of <9> to <14>, wherein the second protective film is in contact with the upper surface of the first protective film and the upper surface of the connection electrode. Method.

<16> The connection electrode is formed by screen printing a metal paste.
The method for manufacturing a thermal print head according to any one of <9> to <15>, wherein the wiring is formed by a lithography process.

<Thermal print head>
The thermal print head according to this embodiment will be described with reference to the drawings.

FIG. 1 is a plan view showing a thermal print head. FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1 and 2 show a part of a thermal print head (corresponding to one thermal print head), and in the present embodiment, this one thermal print head is a piece-shaped thermal print head 100A. .. The thermal print head 100A includes a substrate 15, a heat storage layer 33 on the substrate 15, a common electrode 32 having a plurality of individual electrodes 31 and a comb tooth portion 32A on the heat storage layer 33, and a common electrode 32 on the individual electrode 31 and a common electrode 32. The heat generating resistor 50 on the comb tooth portion 32A, the wiring 41 in contact with the individual electrode 31, the connection electrode 42 in contact with the common electrode 32, the heat storage layer 33, the individual electrode 31, and a part of the common electrode 32. A protective film 52 that covers the heat generation resistor 50 and the wiring 41, and a protective film 54 that covers the connection electrode 42 are provided. Further, the individual electrode 31 is separated from the comb tooth portion 32A of the common electrode 32 in the main scanning direction X and faces the comb tooth portion 32A. The common electrode 32 is made of a material different from that of the connection electrode 42, the end portion of the common electrode 32 in the sub-scanning direction described later is covered with the connection electrode 42, and one of the side surfaces of the connection electrode 42 in the sub-scanning direction is a protective film. It is in contact with 54, and the other side of the side surface of the connection electrode 42 is in contact with the protective film 52.

The heat generation resistor 50 includes a plurality of heat generation resistance portions 51 that generate heat by the current flowing through the individual electrode 31 and the common electrode 32. In the plurality of heat generation resistance portions 51, each heat generation resistance portion 51 is independently formed between the individual electrode 31 and the common electrode 32. In FIG. 1, a plurality of heat generation resistance portions 51 are omitted. The plurality of heat generation resistance portions 51 are arranged linearly on the heat storage layer 33. Further, in FIG. 1, the protective film 54 is omitted for ease of understanding.

In the present embodiment, the direction in which the plurality of heat generation resistance portions 51 extend linearly is 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 the sub-scanning direction Y. The direction corresponding to the thickness of the substrate 15 is defined as the thickness direction Z. In other words, the thickness direction Z is a direction perpendicular to each of the main scanning direction X and the sub-scanning direction Y.

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

A heat storage layer 33 (also referred to as a glaze layer) having a function of accumulating heat is laminated on a substrate 15 made of an alumina substrate or the like. The heat storage layer 33 stores heat generated from the heat generation resistance portion 51 described later. An insulating material can be used for the heat storage layer 33, and for example, silicon oxide or silicon nitride, which are the main components of glass, can be used. The dimension of the heat storage layer 33 in the thickness direction Z is not particularly limited, and is, for example, 30 to 80 μm, preferably 40 to 60 μm.

An individual electrode 31 and a common electrode 32 formed of a metal paste are provided on the heat storage layer 33. The individual electrode 31 and the common electrode 32 are obtained by applying a metal paste by a screen printing method or the like to form an electrode pattern.

As the metal paste, for example, a paste containing metal particles such as copper, silver, palladium, iridium, platinum, and gold can be used. From the viewpoint of metal properties and ionization tendency, copper, silver, platinum, and gold are preferable, and gold is more preferable. Further, the solvent contained in the metal paste has a function of uniformly dispersing the metal particles, and for example, an ester solvent, a ketone solvent, a glycol ether solvent, an aliphatic solvent, an alicyclic solvent, and an aromatic. Examples thereof include, but are not limited to, one type or a mixture of two or more types of a solvent, an alcohol solvent, water and the like.

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

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

The metal paste may be a dispersant, a surface treatment agent, a friction improver, an infrared absorber, an ultraviolet absorber, a fragrance, an antioxidant, an organic pigment, an inorganic pigment, a defoaming agent, or a silane coupling agent, if necessary. , Titanate-based coupling agent, plasticizer, flame retardant, moisturizing agent, ion scavenger and the like can be contained.

Each individual electrode 31 has a strip shape extending in the sub-scanning direction Y, and they do not conduct with each other. Therefore, each individual electrode 31 can be individually applied with different potentials when a printer with a built-in thermal print head is used. An individual pad portion is connected to the end portion of each individual electrode 31. The individual pad portion is provided apart from the heat generation resistor 50 and is in contact with the wiring 41.

The common electrode 32 is a portion that is electrically opposite to the plurality of individual electrodes 31 when a printer incorporating a thermal print head is used. The common electrode 32 has a comb tooth portion 32A and a common portion 32B for connecting the comb tooth portion 32A in common. The common portion 32B is formed in the main scanning direction X along the upper edge of the substrate 15. In the sub-scanning direction Y, the direction in which the common electrode 32 is located when viewed from the individual electrodes 31 is defined as the upper side of the sub-scanning direction Y. Each comb tooth portion 32A has a band shape extending in the sub-scanning direction Y. The tip of each comb tooth portion 32A is located in the region between the tips of two adjacent individual electrodes 31 and faces the two individual electrodes 31 at predetermined intervals along the main scanning direction X. Have been made to.

The tip portion of each comb tooth portion 32A may be opposed to the tip portion of each individual electrode 31 at a predetermined interval along the sub-scanning direction Y. In this case, it is preferable that the heat generation resistance portion 51 is formed only in the region where the tip portion of the comb tooth portion 32A and the tip portion of the individual electrode 31 face each other. In other words, in the main scanning direction X, it is preferable that the heat generation resistance portion 51 is not arranged except in the region where the tip portion of the comb tooth portion 32A and the tip portion of the individual electrode 31 face each other.

In the heat generation resistor 50, the portion where the current flows from the individual electrode 31 and the common electrode 32 generates heat. Specifically, the heat generation resistor 50 to which the heat generation voltage is individually applied according to the print signal transmitted from the outside to the drive IC or the like is selectively generated. The heat generation resistance unit 51 is selectively heated by being individually energized according to the print signal. The heat generated in this way forms print dots. As the heat generation resistor 50, a material having a higher resistivity than the material constituting the individual electrode 31 and the common electrode 32 can be used, and for example, ruthenium oxide or the like can be used. The heat generation resistor 50 can be formed by screen printing or firing a resistor paste supplied by a dispenser. In the present embodiment, the dimension of the heat generation resistor 50 in the thickness direction Z is, for example, about 1 to 10 μm.

The wiring 41 is in contact with the individual electrode 31. The wiring 41 has a function of supplying a voltage from the outside to the individual electrodes 31, and is formed by a lithography process using a metal such as gold or silver, for example.

The connection electrode 42 is in contact with the common electrode 32. The connection electrode 42 has a function of supplying a voltage from the outside to the common electrode 32, and is obtained by, for example, applying a metal paste such as silver by a screen printing method or the like to form an electrode pattern. The electrode pattern is formed by firing the applied metal paste, but the metal paste before firing has higher fluidity than the metal paste after firing, and the electrode pattern is set by this high fluidity. The surface surface of the connection electrode 42, which is formed out of position and is in contact with the surface on which the connection electrode 42 is formed (the surface of the common electrode 32), may increase. However, in the present embodiment, since the connection electrode 42 is formed after the protective film 52 described later is formed, the protective film 52 can suppress the flow of the metal paste even before firing the metal paste. The protective film 52 can suppress the expansion of the surface area of the connection electrode 42 in contact with the surface of the common electrode 32, and can narrow the path through which the material of the connection electrode 42 diffuses toward the comb tooth portion 32A of the common electrode 32. can.

Further, the connection electrode 42 formed by the screen printing method is thicker than the wiring 41 formed by the lithography process. Since the amount of material diffused varies depending on the thickness, the material of the connection electrode 42 and the material of the wiring 41 are the same, the material of the common electrode 32 and the material of the individual electrode 31 are the same, and the material of the connection electrode 42 and the material of the connection electrode 42 are the same. When different from the material of the wiring 41, the amount of the material of the connection electrode 42 diffused to the common electrode 32 is larger than the amount of the material of the wiring 41 diffused to the individual electrode 31. Therefore, the protective film 52 described later is provided so as to be in contact with one of the side surfaces of the connection electrode 42 in the sub-scanning direction, and the protective film 54 is provided so as to be in contact with the other side surface of the connection electrode 42 in the sub-scanning direction. It is possible to prevent the connection electrode 42 from coming into contact with the comb tooth portion 32A in the vicinity of the comb tooth portion 32A of the common electrode 32 which is in contact with the bottom surface of the protective film 52.

The protective film 52 covers the individual electrode 31, a part of the common electrode 32, the wiring 41, the heat generation resistor 50, and the like, and protects them from wear, corrosion, oxidation, and the like. The protective film 52 can be made of an insulating material, for example, made of amorphous glass. The protective film 52 is formed by printing a thick film of glass paste and then firing it. The dimension of the protective film 52 in the thickness direction Z is, for example, about 3 to 8 μm.

The protective film 54 covers at least the connection electrode 42. In the present embodiment, the protective film 54 covers the protective film 52 and the connection electrode 42, and is in contact with the upper surface of the protective film 52 and the upper surface of the connection electrode 42. The protective film 54 is an outermost protective film that directly rubs against the print medium. For example, a protective film containing amorphous glass, sialon, silicon carbide, or silicon nitride as a main component and having a hardness of about 1000 to 2000 HK can be used. .. The dimension of the protective film 54 in the thickness direction Z is, for example, 5 to 8 μm.

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

As shown in FIGS. 3 and 4, a substrate 15 is first prepared, a glass paste is applied onto the substrate 15 by screen printing or the like, the applied glass paste is dried, and then heat treatment is performed on the substrate 15. The heat storage layer 33 is formed in the paste. The firing treatment is performed at, for example, 850 to 1200 ° C. for 1 to 5 hours.

Next, as shown in FIGS. 5 and 6, a plurality of individual electrodes 31 and common electrodes 32 are formed on the heat storage layer 33. The common electrode 32 has a comb tooth portion 32A and a common portion 32B for connecting the comb tooth portion 32A in common. The individual electrode 31 and the common electrode 32 can be obtained by applying the above-mentioned metal paste by screen printing or the like to form an electrode pattern.

Next, as shown in FIGS. 7 and 8, a plurality of wirings 41 in contact with the plurality of individual electrodes 31 are formed. The wiring 41 can be formed by, for example, a lithography process using a metal such as gold or silver.

Next, as shown in FIGS. 9 and 10, a heat generation resistor 50 (heat generation resistance portion 51) is formed on the individual electrode 31 and the comb tooth portion 32A of the common electrode 32 by the thick film forming technique. The heat generation resistor 50 is formed by screen printing or firing a resistor paste supplied by a dispenser. The resistor paste contains, for example, ruthenium oxide.

Next, as shown in FIGS. 11 and 12, a protective film 52 that covers the individual electrode 31, a part of the common electrode 32, the wiring 41, and the heat generation resistor 50 is formed. The protective film 52 is made of, for example, amorphous glass. The protective film 52 is formed by printing a thick film of glass paste and then firing it.

Next, as shown in FIGS. 13 and 14, a connection electrode 42 in contact with the common electrode 32 is formed. The connection electrode 42 is obtained, for example, by applying a metal paste such as silver by a screen printing method or the like to form an electrode pattern. Since the protective film 52 suppresses the flow of the metal paste before firing the metal paste, the protective film 52 can suppress the expansion of the surface area of the connection electrode 42 in contact with the surface of the common electrode 32.

Next, as shown in FIGS. 15 and 16, a protective film 54 that at least covers the connection electrode 42 is formed. The protective film 54 is an outermost protective film that directly rubs against the print medium. For example, a protective film containing amorphous glass, sialon, silicon carbide, or silicon nitride as a main component and having a hardness of about 1000 to 2000 HK can be used. .. The dimension of the protective film 54 in the thickness direction Z is, for example, 5 to 8 μm.

By the above steps, the thermal print head of the present embodiment can be manufactured.

According to the present embodiment, since the connection electrode 42 is formed after the protective film 52 is formed, the protective film 52 can suppress the flow of the metal paste even before firing the metal paste. The protective film 52 can suppress the expansion of the surface area of the connection electrode 42 in contact with the surface of the common electrode 32, and can narrow the path through which the material of the connection electrode 42 diffuses toward the comb tooth portion 32A of the common electrode 32. can. Further, the protective film 52 is provided so as to be in contact with one of the side surfaces of the connection electrode 42 in the sub-scanning direction, and the protective film 54 is provided so as to be in contact with the other side surface of the connection electrode 42 in the sub-scanning direction. It is possible to suppress the connection electrode 42 from coming into contact with the comb tooth portion 32A in the vicinity of the comb tooth portion 32A of the common electrode 32 in contact with the bottom surface of the 52. Therefore, it is possible to suppress the disconnection of the comb tooth portion 32A of the common electrode 32.

(Other embodiments)
As mentioned above, one embodiment has been described, but the statements and drawings that form part of the disclosure are exemplary and should not be understood to be limiting. This disclosure will reveal to those skilled in the art various alternative embodiments, examples and operational techniques. As described above, the present embodiment includes various embodiments not described here.

For example, as shown in FIG. 17, the thermal print head 100B, which is a modification of the thermal print head 100A, may be configured to provide a connection electrode 42a having a protruding portion instead of the connection electrode 42. Since the metal paste before firing, which serves as the connection electrode 42, has high fluidity, it may get over the protective film 52, and the above-mentioned protrusion is in contact with at least a part of the upper surface of the protective film 52.

Further, as in the thermal print head 100C shown in FIG. 18 and the thermal print head 100D shown in FIG. 19, the protective film 54 may be configured to cover at least the connection electrode 42 instead of the whole.

<Thermal printer>
In the thermal print head of the present embodiment (for example, the thermal print head 100A), as shown in FIG. 20, the substrate 15 (the heat storage layer 33, the individual electrodes 31, the common electrode 32, etc. on the substrate 15 are not shown). A connection board 5, a heat dissipation member 8, a drive IC 7, a plurality of wires 81, a resin portion 82, and a connector 59 are provided. The substrate 15 and the connection substrate 5 are mounted on the heat radiating member 8 so as to be adjacent to each other in the sub-scanning direction Y. A plurality of heat generation resistance portions 51 arranged in the main scanning direction X are formed on the substrate 15. The heat generation resistance portion 51 is driven so as to selectively generate heat by the drive IC 7 mounted on the connection substrate 5. The heat generation resistance unit 51 prints on a printing medium 92 such as thermal paper pressed by the platen roller 91 against the heat generation resistance unit 51 according to a print signal transmitted from the outside via the connector 59.

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

The heat radiating member 8 has a function of dissipating heat from the substrate 15. A substrate 15 and a connection substrate 5 are attached to the heat radiating member 8. For the heat radiating member 8, for example, a metal such as aluminum can be used.

As the wire 81, for example, a conductor such as gold can be used. There are a plurality of wires 81, and a part of them is connected to the drive IC 7 and each individual electrode by bonding. Further, a part of the other wires 81 is bonded to the drive IC 7 and the connector 59 via the wiring layer in the connection board 5.

For the resin portion 82, for example, a black resin can be used. As the resin portion 82, for example, an epoxy resin, a silicone resin, or the like can be used. The resin portion 82 covers the drive IC 7 and the plurality of wires 81, and protects the drive IC 7 and the plurality of wires 81. The connector 59 is fixed to the connection board 5. Wiring for supplying electric power to the thermal printhead from the outside of the thermal printhead and controlling the drive IC 7 is connected to the connector 59.

The thermal printer of this embodiment can include the above-mentioned thermal print head. The thermal printer prints on a print medium conveyed along the sub-scanning direction Y. Normally, the print medium is conveyed from the connector 59 side toward the heat generation resistance portion 51 side. Examples of the print medium include a bar code sheet, thermal paper for producing a receipt, and the like.

The thermal printer includes, for example, a thermal print head 100A, a platen roller 91, a main power supply circuit, a measurement circuit, and a control unit. The platen roller 91 faces the thermal print head 100A.

The main power supply circuit supplies electric power to a plurality of heat generation resistance portions 51 in the thermal print head 100A. The measurement circuit measures the resistance value of each of the plurality of heat generation resistance portions 51. The measurement circuit measures, for example, the resistance value of each of the plurality of heat generation resistance units 51 when printing is not performed on the print medium. This makes it possible to confirm the life of the heat generation resistance unit 51 and the presence or absence of the failed heat generation resistance unit 51. The control unit controls the drive state of the main power supply circuit and the measurement circuit. The control unit controls the energization state of each of the plurality of heat generation resistance units 51. The measurement circuit may be omitted.

The connector 59 is used to communicate with a device outside the thermal printhead 100A. The thermal print head 100A is electrically connected to the main power supply circuit and the measurement circuit via the connector 59. The thermal print head 100A is electrically connected to the control unit via the connector 59.

The drive IC 7 receives a signal from the control unit via the connector 59. The drive IC 7 controls the energization state of each of the plurality of heat generation resistance units 51 based on the signal received from the control unit. Specifically, the drive IC 7 selectively energizes a plurality of individual electrodes to arbitrarily generate heat in any of the plurality of heat generation resistance portions 51.

Next, how to use the thermal printer will be described.

At the time of printing on a print medium, the potential v11 is applied to the connector 59 as the potential V1 from the main power supply circuit. In this case, the plurality of heat generation resistance portions 51 selectively energize and generate heat. By transferring the heat to the print medium, printing on the print medium is performed. As described above, when the potential v11 is applied to the connector 59 as the potential V1 from the main power supply circuit, an energization path to each of the plurality of heat generation resistance portions 51 is secured.

When printing is not performed on the print medium, the resistance value of each heat generation resistance unit 51 is measured. At the time of the measurement, no potential is applied to the connector 59 from the main power supply circuit. At the time of measuring the resistance value of each heat generation resistance unit 51, the potential v12 is applied to the connector 59 as the potential V1 from the measurement circuit. In this case, the plurality of heat generation resistance portions 51 are energized in order (for example, in order from the heat generation resistance portion 51 located at the end of the main scanning direction X). The measurement circuit measures the resistance value of each heat generation resistance unit 51 based on the value of the current flowing through the heat generation resistance unit 51 and the potential v12. As described above, when the potential v11 is applied to the connector 59 as the potential V1 from the main power supply circuit, the energization path to each of the plurality of heat generation resistance portions 51 is substantially cut off. As a result, the resistance value of each heat generation resistance unit 51 can be measured more accurately by the measurement circuit, and the life of the heat generation resistance unit 51 and the presence or absence of the failed heat generation resistance unit 51 can be confirmed.

According to this embodiment, it is possible to obtain a thermal printer in which disconnection of the comb tooth portion of the common electrode is suppressed.

5 Connection board 7 Drive IC
8 Heat dissipation member 15 Substrate 31 Individual electrode 32 Common electrode 32A Comb tooth part 32B Common part 33 Heat storage layer 41 Wiring 42, 42a Connection electrode 50 Heat generation resistor 51 Heat generation resistance part 52, 54 Protective film 59 Connector 81 Wire 82 Resin part 91 Platen Roller 92 Printing medium 100A, 100B, 100C, 100D, Thermal print head

Claims (16)

With the heat storage layer,
The individual electrodes on the heat storage layer and
A common electrode having a comb tooth portion separated from the individual electrode and facing the individual electrode,
With the individual electrode and the heat generation resistor on the comb tooth portion,
A connection electrode made of a material different from the common electrode and in contact with the common electrode,
The heat generation resistor, the individual electrode, and the first protective film covering a part of the common electrode,
A second protective film covering the connection electrode is provided.
The end of the common electrode in the sub-scanning direction is covered with the connection electrode.
A thermal printhead in which one side surface of the connection electrode in the sub-scanning direction is in contact with the second protective film, and the other side surface of the connection electrode is in contact with the first protective film. The common electrode contains gold and
The thermal print head according to claim 1, wherein the connection electrode contains silver. Further, it is provided with wiring in contact with the individual electrodes.
The thermal print head according to claim 1 or 2, wherein the connection electrode is thicker than the wiring. The connection electrode has a protrusion and has a protrusion.
The thermal print head according to any one of claims 1 to 3, wherein the protruding portion is in contact with at least a part of the upper surface of the first protective film. The thermal print head according to any one of claims 1 to 4, wherein the second protective film covers the first protective film. The thermal print head according to any one of claims 1 to 5, wherein the second protective film is in contact with the upper surface of the first protective film and the upper surface of the connection electrode. The thermal print head according to any one of claims 1 to 6, wherein the individual electrode is separated from the comb tooth portion in the main scanning direction. A thermal printer comprising the thermal print head according to any one of claims 1 to 7. Form a heat storage layer,
An individual electrode and a common electrode having a comb tooth portion are formed on the heat storage layer.
A wiring in contact with the individual electrode is formed, and the wiring is formed.
A heat generation resistor is formed on the individual electrode and the common electrode.
A first protective film covering the heat generation resistor, the individual electrode, a part of the common electrode, and the wiring is formed.
After the formation of the first protective film, a connection electrode in contact with the other part of the common electrode is formed.
A second protective film covering the connection electrode is formed, and the second protective film is formed.
The individual electrode is separated from the comb tooth portion of the common electrode and faces the comb tooth portion.
A method for manufacturing a thermal print head, wherein the common electrode is made of a material different from that of the connection electrode. The end of the common electrode in the sub-scanning direction is covered with the connection electrode.
The thermal print according to claim 9, wherein one side surface of the connection electrode in the sub-scanning direction is in contact with the second protective film, and the other side surface of the connection electrode is in contact with the first protective film. How to make the head. The common electrode contains gold and
The method for manufacturing a thermal printhead according to claim 9 or 10, wherein the connection electrode contains silver. The method for manufacturing a thermal print head according to any one of claims 9 to 11, wherein the connection electrode is thicker than the wiring. The connection electrode has a protrusion and has a protrusion.
The method for manufacturing a thermal printhead according to any one of claims 9 to 12, wherein the protruding portion is in contact with at least a part of the upper surface of the first protective film. The method for manufacturing a thermal print head according to any one of claims 9 to 13, wherein the second protective film covers the first protective film. The method for manufacturing a thermal printhead according to any one of claims 9 to 14, wherein the second protective film is in contact with the upper surface of the first protective film and the upper surface of the connection electrode. The connection electrode is formed by screen printing a metal paste.
The method for manufacturing a thermal print head according to any one of claims 9 to 15, wherein the wiring is formed by a lithography process.

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