JP2022163429A - Thermal print head and manufacturing method of the same and thermal printer - Google Patents

Abstract

To provide a thermal print head which secures good printing performance, and to provide a manufacturing method of the thermal print head and a thermal printer including the thermal print head.SOLUTION: A thermal print head 100 includes: an insulator; a heat accumulation layer 33 disposed on the insulator; a protection film 34A disposed on the heat accumulation layer 33 and having a groove part 38; a heating resistance element 40 disposed on the heat accumulation layer 33 and embedded in the groove part 38; an individual electrode 31 electrically connected to the heating resistance element 40; a common electrode 32 having a comb teeth part 32A electrically connected with the heating resistance element 40; and a protection film 34B which covers the heating resistance element 40 and the protection film 34A. The individual electrode 31 is spaced apart from the comb teeth part 32A of the common electrode 32 and faces the comb teeth part 32A.SELECTED DRAWING: Figure 1

Description

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

A thermal print head, for example, has a large number of heat generating portions arranged in the main scanning direction on a head substrate. Each heat generating portion is formed by laminating a common electrode and an individual electrode on a resistor layer formed on a head substrate with a glaze layer interposed therebetween, with their ends facing each other, with a portion of the resistor layer exposed. It is 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 print medium (a bar code sheet, thermal paper for creating a receipt, etc.), printing is performed on the print medium.

For example, in a distribution center or the like, the sorting of goods, the details of the contents, and the slip number are printed on a label, and the label is used to simplify and improve the efficiency of inspection work.

However, in recent years, traceability has become more important, and all kinds of information, such as factory unique codes, manufacturing dates, and expiry dates, are now printed on labels, receipts, and other printed media. The amount of printed information and the amount of label printing in the field of logistics are on the rise, such as mandatory labeling and changes to allergy labeling.

In order to enable high-volume printing, which is on the rise, thermal printheads need to print information on print media at high speed and with high definition. In order to print at high speed and high definition (improve printing performance), it is necessary to narrow the pitch of the heating portions.

JP 2006-159866 A

A heat-generating portion is formed in a portion of the glaze layer that bulges upward, and a protective film is arranged so as to cover the heat-generating portion. However, in order to completely cover the end portion of the heat generating portion with the protective film, it is necessary to form the protective film thick in consideration of the coverage of the end portion of the heat generating portion. Since the heat generated from the heat-generating portion is transferred to the printing medium through the protective film, if the protective film is too thick, the heat cannot be efficiently transferred to the printing medium, and printing performance may deteriorate. One aspect of the present embodiment provides a thermal printhead that ensures good printing performance. Another aspect of the present embodiment provides a method for manufacturing the thermal printhead. Another aspect of the present embodiment provides a thermal printer including the thermal print head.

In this embodiment, a first protective film having a groove is used to form a heating resistor electrically connected to an individual electrode and a common electrode in the groove, and a thin second protective film covering the heating resistor is formed. By doing so, the printing performance of the thermal print head can be improved. One aspect of this embodiment is as follows.

One aspect of the present embodiment includes an insulator, a heat storage layer disposed on the insulator, a first protective film disposed on the heat storage layer and having a groove, and It has a heating resistor arranged and embedded in the groove, an individual electrode electrically connected to the heating resistor, and a comb tooth portion electrically connected to the heating resistor. A common electrode and a second protective film covering the heating resistor and the first protective film, wherein the individual electrode is spaced apart from the comb tooth portion of the common electrode and the comb tooth portion. Facing, thermal printheads.

Another aspect of the present embodiment is a thermal printer including the thermal print head.

In another aspect of the present embodiment, a heat storage layer is formed on an insulator, a common electrode having a comb tooth portion and individual electrodes are formed on the heat storage layer, and the individual electrodes are formed on the heat storage layer. A resist is formed on the electrodes and the comb teeth, a first protective film having grooves is formed using the resist, and the grooves are electrically connected to the individual electrodes and the common electrode. A heating resistor is formed, a second protective film is formed to cover the heating resistor and the first protective film, the individual electrode is spaced apart from the comb teeth of the common electrode, and the comb teeth are separated from each other. and a method of manufacturing a thermal printhead.

In another aspect of the present embodiment, a heat storage layer is formed on an insulator, a resist is formed on the heat storage layer, a first protective film having a groove is formed using the resist, forming a heating resistor in the groove, forming a common electrode having a comb tooth portion and individual electrodes on the heating resistor and the first protective film, and forming the heating resistor and the first protective film; forming a second protective film covering the film, the common electrode, and the individual electrodes, the individual electrodes being spaced apart from and facing the comb teeth of the common electrode; A method of manufacturing a printhead.

According to this embodiment, it is possible to provide a thermal print head that ensures good printing performance. Also, a method for manufacturing the thermal print head can be provided. Furthermore, it is possible to provide a thermal printer equipped with the thermal print head.

FIG. 1 is a partial perspective view illustrating a thermal printhead according to the first embodiment. 2 is a partial cross-sectional view along line AA in FIG. 1 in the main scanning direction X. FIG. 3 is a partial cross-sectional view along the line BB in FIG. 1 in the sub-scanning direction Y. FIG. FIG. 4 is an enlarged cross-sectional view of the periphery of the heating resistor. FIG. 5 is an enlarged perspective view of a heating resistor. FIG. 6 is a partial perspective view explaining the method of manufacturing the thermal print head according to the first embodiment (No. 1). 7 is a partial cross-sectional view along line AA in FIG. 6 in the main scanning direction X. FIG. 8 is a partial cross-sectional view along the line BB in FIG. 6 in the sub-scanning direction Y. FIG. FIG. 9 is a partial perspective view explaining the method of manufacturing the thermal print head according to the first embodiment (No. 2). 10 is a partial cross-sectional view along line AA in FIG. 9 in the main scanning direction X. FIG. 11 is a partial cross-sectional view along the line BB in FIG. 9 in the sub-scanning direction Y. FIG. FIG. 12 is a partial perspective view explaining the method of manufacturing the thermal print head according to the first embodiment (No. 3). 13 is a partial cross-sectional view along line AA in FIG. 12 in the main scanning direction X. FIG. 14 is a partial cross-sectional view along line BB in FIG. 12 in the sub-scanning direction Y. FIG. FIG. 15 is a partial perspective view explaining the method of manufacturing the thermal print head according to the first embodiment (No. 4). 16 is a partial cross-sectional view along line AA in FIG. 15 in the main scanning direction X. FIG. 17 is a partial cross-sectional view along line BB in FIG. 15 in the sub-scanning direction Y. FIG. FIG. 18 is a partial perspective view explaining the method of manufacturing the thermal print head according to the first embodiment (No. 5). 19 is a partial cross-sectional view along line AA in FIG. 18 in the main scanning direction X. FIG. 20 is a partial cross-sectional view along line BB in FIG. 18 in the sub-scanning direction Y. FIG. FIG. 21 is a partial perspective view explaining the method of manufacturing the thermal print head according to the first embodiment (No. 6). 22 is a partial cross-sectional view along line AA in FIG. 21 in the main scanning direction X. FIG. 23 is a partial cross-sectional view along line BB in FIG. 21 in the sub-scanning direction Y. FIG. FIG. 24 is a cross-sectional view for explaining a thermal printhead according to the second embodiment. 25 is a partial cross-sectional view along line AA in FIG. 24 in the main scanning direction X. FIG. 26 is a partial cross-sectional view along line BB in FIG. 24 in the sub-scanning direction Y. FIG. FIG. 27 is a partial perspective view explaining a method of manufacturing a thermal print head according to the second embodiment (No. 1). 28 is a partial cross-sectional view along line AA in FIG. 27 in the main scanning direction X. FIG. 29 is a partial cross-sectional view along line BB in FIG. 27 in the sub-scanning direction Y. FIG. FIG. 30 is a partial perspective view explaining the method of manufacturing the thermal print head according to the second embodiment (No. 2). 31 is a partial cross-sectional view along line AA in FIG. 30 in the main scanning direction X. FIG. 32 is a partial cross-sectional view along the line BB in FIG. 30 in the sub-scanning direction Y. FIG. FIG. 33 is a partial perspective view explaining the method of manufacturing the thermal print head according to the second embodiment (No. 3). 34 is a partial cross-sectional view along line AA in FIG. 33 in the main scanning direction X. FIG. 35 is a partial cross-sectional view along line BB in FIG. 33 in the sub-scanning direction Y. FIG. FIG. 36 is a partial perspective view for explaining the method of manufacturing the thermal print head according to the second embodiment (No. 4). 37 is a partial cross-sectional view along line AA in FIG. 36 in the main scanning direction X. FIG. 38 is a partial cross-sectional view along line BB in FIG. 36 in the sub-scanning direction Y. FIG. FIG. 39 is a cross-sectional view illustrating a thermal printhead.

Next, this embodiment will be described with reference to the drawings. In the description of the drawings described below, the same or similar parts are denoted 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 planar dimensions, etc., differs from the actual one. Therefore, specific thicknesses and dimensions should be determined with reference to the following description. In addition, it goes without saying that there are portions with different dimensional relationships and ratios between the drawings.

Further, the embodiments shown below are examples of apparatuses and methods for embodying technical ideas, and do not specify the material, shape, structure, arrangement, etc. of each component. Various modifications can be made to this embodiment within the scope of the claims.

One specific aspect of this embodiment is as follows.

<1> an insulator, a heat storage layer placed on the insulator, a first protective film placed on the heat storage layer and having a groove, a first protective film placed on the heat storage layer, and a heating resistor embedded in the groove, an individual electrode electrically connected to the heating resistor, a common electrode having a comb tooth electrically connected to the heating resistor, and a second protective film covering the heating resistor and the first protective film, wherein the individual electrode is spaced apart from the comb tooth portion of the common electrode and faces the comb tooth portion; thermal print head.

<2> The thermal print head according to <1>, wherein the heat generating resistors are arranged on the individual electrodes and on the comb tooth portion.

<3> The thermal printhead according to <1>, wherein the individual electrodes and the common electrode are arranged on the heating resistor and the first protective film.

<4> Any one of <1> to <3>, located on the insulator side of the interface between the heating resistor, the second protective film, the first protective film, and the second protective film The thermal printhead described in .

<5> A portion of the main surface of the second protective film on the side opposite to the side on which the first protective film is located, which overlaps the heating resistor when viewed from the normal direction of the main surface is a flat surface, the thermal print head according to any one of <1> to <4>.

<6> The thermal printhead according to any one of <1> to <5>, wherein the main surface of the heating resistor on the side where the second protective film is located has a concave curved surface.

<7> The thermal printhead according to any one of <1> to <6>, wherein the insulator is a substrate.

<8> The thermal print head according to <7>, wherein the substrate is made of ceramic.

<9> A thermal printer comprising the thermal print head according to any one of <1> to <8>.

<10> A heat storage layer is formed on an insulator, a common electrode having a comb tooth portion and an individual electrode are formed on the heat storage layer, and the heat storage layer, the individual electrode, and the comb tooth portion are formed. a first protective film having grooves is formed using the resist; a heating resistor electrically connected to the individual electrode and the common electrode is formed in the groove; Thermal printing, wherein a second protective film is formed to cover the resistor and the first protective film, and the individual electrodes are separated from and face the comb teeth of the common electrode. How the head is made.

<11> A heat storage layer is formed on an insulator, a resist is formed on the heat storage layer, a first protective film having a groove is formed using the resist, and a heating resistor is formed in the groove. , a common electrode having a comb tooth portion and individual electrodes are formed on the heating resistor and the first protective film, and the heating resistor, the first protective film, the common electrode, and the individual electrodes are formed. A method of manufacturing a thermal print head, wherein a second protective film is formed to cover electrodes, and the individual electrodes are separated from and face the comb teeth of the common electrode.

<12> The method of manufacturing a thermal print head according to <10> or <11>, wherein the first protective film is formed by baking a material paste that becomes the first protective film.

<13> Any one of <10> to <12>, wherein the heating resistor is formed by embedding a resistor paste in the groove of the first protective film and firing the resistor paste. 3. A method of manufacturing a thermal printhead according to .

<14> The method of manufacturing a thermal print head according to any one of <10> to <13>, wherein the heating resistor is formed by screen printing.

<15> The method of manufacturing a thermal print head according to any one of <10> to <13>, wherein the heating resistor is formed using a mask.

<16> The method of manufacturing a thermal printhead according to <15>, wherein the mask is a stencil mask.

<17> The first protective film is formed through a baking step, and the resist is removed by one or more steps selected from the group consisting of the baking step and an organic peeling step, <10> to < 16>.

<18> The method of manufacturing a thermal print head according to any one of <10> to <17>, wherein the main surface of the heating resistor on the side where the second protective film is located has a concave curved surface. .

<Thermal print head>
(First embodiment)
A thermal print head according to this embodiment will be described with reference to the drawings.

FIG. 1 is a partial perspective view showing a thermal printhead. 2 is a partial cross-sectional view along line AA in FIG. 1 in the main scanning direction X. FIG. 3 is a partial cross-sectional view along the line BB in FIG. 1 in the sub-scanning direction Y. FIG. 1 to 3 show a portion of a thermal print head (corresponding to one thermal print head), and in this embodiment, this one thermal print head is assumed to be an individual thermal print head 100. . The thermal print head 100 includes a substrate 15 that is an insulator, a heat storage layer 33 on the substrate 15, a plurality of individual electrodes 31 on the heat storage layer 33, a common electrode 32 on the heat storage layer 33, on the heat storage layer 33, A protective film 34A having grooves 38 on the plurality of individual electrodes 31 and the common electrode 32; and a protective film 34B covering the plurality of heat generating resistors 40 and the protective film 34A. The heating resistor 40 is electrically connected to the individual electrodes 31 and the common electrode 32 . Each of the individual electrodes 31 is separated from the comb tooth portion 32A of the common electrode 32 so as to sandwich each of the heating resistors 40, and faces the comb tooth portion 32A. Also, the heating resistor 40 includes a heating resistor portion 41 that generates heat by current flowing through the individual electrodes 31 and the common electrode 32 . The plurality of heat generating resistors 41 are formed independently between the individual electrodes 31 and the common electrode 32 . FIG. 1 omits illustration of the plurality of heating resistors 41 . The plurality of heat generating resistors 41 are linearly arranged on the heat storage layer 33 .

In this embodiment, the main scanning direction X is the direction in which the plurality of heating resistors 41 extend linearly, and the sub-scanning direction Y is the direction perpendicular to the main scanning direction X and parallel to the upper surface of the substrate 15 . , the direction corresponding to the thickness of the substrate 15 is defined as a thickness direction Z. As shown in FIG. In other words, the thickness direction Z is a direction perpendicular to the main scanning direction X and the sub-scanning direction Y, respectively. Also, the direction in which the heat storage layer 33 is located when viewed from the substrate 15 is defined as the upward direction, and the direction in which the substrate 15 is located when viewed from the heat storage layer 33 is defined as the downward direction.

The substrate 15 is an insulator and is made of ceramic, for example. As the ceramic, for example, alumina or the like can be used. From the viewpoint of heat dissipation, it is preferable to use alumina, which has relatively high thermal conductivity, for the substrate 15 .

A heat storage layer 33 (also referred to as a glaze layer) having a function of storing heat is laminated on the substrate 15 . The heat storage layer 33 accumulates heat generated from the heating resistor section 41, which will be described later. An insulating material can be used for the heat storage layer 33, and for example, silicon oxide and silicon nitride, which are 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, 5 to 100 μm, preferably 10 to 30 μm.

An individual electrode 31 and a common electrode 32 made of metal paste are provided on the heat storage layer 33 . The individual electrodes 31 and the common electrode 32 are obtained by applying a metal paste by screen printing or the like and then baking it 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. Copper, silver, platinum, and gold are preferred from the viewpoint of metal properties and ionization tendency, and silver is more preferred from the viewpoint of metal properties, ionization tendency, and cost reduction. In addition, the solvent contained in the metal paste has a function of uniformly dispersing the metal particles, and examples thereof include ester solvents, ketone solvents, glycol ether solvents, aliphatic solvents, alicyclic solvents, and aromatic solvents. Examples include, but are not limited to, one or a mixture of two or more of solvent, alcohol, water, and the like.

Examples of ester solvents include ethyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, amyl acetate, ethyl lactate and dimethyl carbonate. Ketone solvents include, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone benzene, diisobutyl ketone, diacetone alcohol, isophorone, cyclohexanone and the like. Glycol ether-based solvents include, for example, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether and the like, acetic acid esters of these monoethers, 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, acetic acid esters of these monoethers, and the like.

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

The metal paste may contain dispersants, surface treatment agents, anti-friction agents, infrared absorbers, ultraviolet absorbers, fragrances, antioxidants, organic pigments, inorganic pigments, antifoaming agents, silane coupling agents, if necessary. , a titanate-based coupling agent, a plasticizer, a flame retardant, a humectant, an ion scavenger, and the like.

Each individual electrode 31 has a strip shape extending generally in the sub-scanning direction Y, and they are not electrically connected to each other. Therefore, each individual electrode 31 can be individually given different potentials when a printer incorporating a thermal print head is used. An end portion of each individual electrode 31 is connected to an individual pad portion (not shown).

The common electrode 32 is a portion electrically opposite in polarity 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 that commonly connects the comb tooth portions 32A. The common portion 32B is formed in the main scanning direction X along the edge of the substrate 15 on the upper side. 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. FIG. Each comb tooth portion 32A has a strip shape extending in the sub-scanning direction Y. As shown in FIG. The tip of each comb tooth portion 32A faces the tip of each individual electrode 31 along the sub-scanning direction Y with a predetermined gap therebetween. With such a configuration, the pitch of the heating resistors 40 can be narrowed, so that high-definition printing is possible.

The protective film 34A has grooves 38 . The individual electrodes 31, the common electrode 32, etc. are covered with a protective film 34A to protect the individual electrodes 31, the common electrode 32, etc. from abrasion, corrosion, oxidation, and the like. The protective film 34A can be made of an insulating material, such as amorphous glass. The protective film 34A is formed by printing a thick film of glass paste and then baking it. The dimension in the thickness direction Z of the protective film 34A is, for example, about 1 to 10 μm.

The heating resistor 40 is electrically connected to the individual electrode 31 and the common electrode 32, and heat is generated in the portion to which the current from the individual electrode 31 and the common electrode 32 flows. Specifically, the heating resistors 40 (heating resistor portions 41) to which a heating voltage is individually applied in accordance with a print signal sent from the outside to the driving IC or the like are selectively caused to generate heat. The heating resistors 41 are selectively heated by being individually energized according to the print signal. Print dots are formed by such heat generation. The heating resistor 40 is made of a material having a higher resistivity than the material of the individual electrodes 31 and the common electrode 32, such as ruthenium oxide.

The heating resistor 40 can be formed by embedding resistor paste in the grooves 38 of the protective film 34A and firing the paste. In this embodiment, the dimension in the thickness direction Z of the heating resistor 40 is, for example, about 1 to 10 μm.

The resistor paste that forms the heating resistor 40 shrinks when fired. For example, even if the resistor paste is supplied so as to completely fill the grooves 38, the surface in contact with the protective film 34B of the heat generating resistor 40 is protected by baking as shown in FIG. It is closer to the substrate 15 than the surface of the film 34A in contact with the protective film 34B. In other words, the interface between the heating resistor 40 and the protective film 34B is closer to the substrate 15 (lower side) than the interface between the protective films 34A and 34B. In addition, when the protective film 34A and the protective film 34B are made of the same material and it is difficult to distinguish the boundary, the main surface of the protective film 34B (the main surface of the protective film 34B opposite to the side where the protective film 34A is located) A boundary surface between the protective film 34A and the protective film 34B is defined as a portion separated from the protective film 34B by the thickness of the protective film 34B. When the boundary surface between the heating resistor 40 and the protective film 34B is closer to the substrate 15 than the boundary surface between the protective films 34A and 34B, the edge of the heating resistor 40 is located at the boundary between the protective films 34A and 34B. Since it is located on the substrate 15 side of the plane, it is possible to completely cover the ends of the heating resistor 40 with the protective film 34B, which is preferable.

Further, of the main surface of the protective film 34B opposite to the side where the protective film 34A is located, even if the portion overlapping the heating resistor 40 when viewed from the normal direction of the main surface is a flat surface. good. In this specification and the like, the term “flat surface” includes a surface having an average surface roughness of 0.5 μm or less. Note that the average surface roughness can be obtained in accordance with JIS B 0601:2013 and ISO 25178, for example. It is preferable that the portion overlapping with the heating resistor 40 is a flat surface because it can easily come into contact with the platen roller of the thermal print head.

As shown in FIG. 5, the heating resistor 40 may have a concave curved surface 40A on the main surface (the surface opposite to the surface on which the heat storage layer 33 is located). In the step of forming the heating resistor 40, the resistor paste is embedded in the grooves 38 of the protective film 34A and fired, so that the resistor paste has a concave curved surface 40A due to the surface tension between the resistor paste and the protective film 34A. Sometimes. It is preferable that the main surface of the heating resistor 40 has a concave curved surface 40A because the protective film 34B and the like can be formed with good coverage.

The heating resistor 40, the protective film 34A, and the like are covered with a protective film 34B, which protects the heating resistor 40, the protective film 34A, and the like from wear, corrosion, oxidation, and the like. The protective film 34B can be made of an insulating material, such as amorphous glass. The protective film 34B is formed by printing a thick film of glass paste and then baking it. The dimension in the thickness direction Z of the protective film 34B is, for example, about 2 to 8 μm. A thickness within this range is preferable because it is possible to obtain the thermal print head 100 capable of suppressing defective pressure resistance and maintaining good print quality. Even if the protective film 34B is thin, it can completely cover the ends of the heating resistors 40, and the printing performance of the thermal print head 100 can be improved.

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

As shown in FIGS. 6 to 8, first, the substrate 15 is prepared, and the heat storage layer 33 is formed on the substrate 15. As shown in FIGS. Next, the wiring layer 30 is formed on the heat storage layer 33 .

The heat storage layer 33 can be formed by, for example, applying a glass paste by screen printing or the like, drying the applied glass paste, and then performing a firing treatment. The baking treatment is performed, for example, at 800 to 1200° C. for 10 minutes to 1 hour. The dimension in the thickness direction Z of the heat storage layer 33 is, for example, 25 μm.

The wiring layer 30 becomes individual electrodes 31 and a common electrode 32 which are formed later. The wiring layer 30 is obtained by applying the above-described metal paste, which will become the individual electrodes 31 and the common electrode 32, by screen printing or the like, and then baking the paste.

Next, as shown in FIGS. 9 to 11, the wiring layer 30 is etched to form individual electrodes 31 and a common electrode 32. Next, as shown in FIGS.

Next, as shown in FIGS. 12 to 14, a resist 36 is formed on the heat storage layer 33, the individual electrodes 31, and the common electrode 32. Next, as shown in FIGS. A heating resistor 40 will be formed later in the region where the resist 36 exists. Since a defective shape pattern of the resist 36 is related to a defective shape pattern of the heating resistor 40 to be formed later, it is preferable to appropriately adjust the etching conditions to form the resist 36 with high accuracy. A groove portion 38 having a desired shape can be formed by forming the resist 36 into a desired shape, and a desired heating resistor 40 can be obtained from the groove portion 38 . Therefore, by processing the shape pattern of the resist 36 with high accuracy, it is possible to reduce defects in the shape pattern of the heating resistor 40 .

Next, as shown in FIGS. 15 to 17, a protective film 34A is formed on the heat storage layer 33, the individual electrodes 31, and the common electrode 32 where the resist 36 is not provided. The protective film 34A is made of amorphous glass, for example. The protective film 34A is formed by printing a material paste (for example, glass paste) for the protective film 34A in a thick film and then baking the printed material.

Next, as shown in FIGS. 18 to 20, the resist 36 is removed by the baking process for forming the protective film 34A, and grooves 38 are formed in the protective film 34A. Resist 36 may be removed using an organic stripping process. Solvents that can be used in the organic stripping step include stripping solution 10 manufactured by Tokyo Ohka Kogyo Co., Ltd., for example.

By forming the protective film 34A using the resist 36 in this manner, the grooves 38 can be easily formed in the protective film 34A without using an etchant such as hydrofluoric acid that requires careful handling. .

Next, as shown in FIGS. 21 to 23, a resistor paste that will become the heating resistor 40 (heating resistor portion 41) is formed so as to fill the groove portion 38. Next, as shown in FIG. Resistor paste is supplied to the grooves 38 using a mask such as screen printing or a stencil mask. For example, it is preferable to supply the resistor paste using a stencil mask because the printing accuracy is improved. The resistor paste contains, for example, ruthenium oxide.

Next, the heating resistor 40 (heating resistor portion 41) is formed by firing the resistor paste described above.

In the step of forming the heating resistor 40, the resistor paste is embedded in the grooves 38 of the protective film 34A and fired, so that the surface tension between the resistor paste and the protective film 34A causes the main surface of the heating resistor 40 to be concave. curved surface 40A. It is preferable that the main surface of the heating resistor 40 has a concave curved surface 40A because the protective film 34B and the like can be formed with good coverage.

Next, as shown in FIGS. 1 to 3, a protective film 34B is formed. The protective film 34B is made of amorphous glass, for example. The protective film 34B is formed by printing a thick film of glass paste and then baking it.

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

According to this embodiment, since the heat generating resistor 40 is formed so as to be embedded in the groove 38, even if the protective film 34B is thin, the edge of the heat generating resistor 40 can be completely covered, and the thermal print head can be easily mounted. 100 can be improved. In addition, since the heating resistor 40 is formed in the groove 38 of the protective film 34A without forming a plurality of heating resistors by wet etching or the like based on one heating resistor, the pattern shape of each heating resistor can be changed. Defects can be reduced.

(Second embodiment)
A thermal print head according to this embodiment will be described with reference to the drawings.

FIG. 24 is a partial perspective view showing a thermal printhead. 25 is a partial cross-sectional view along line AA in FIG. 24 in the main scanning direction X. FIG. 26 is a partial cross-sectional view along line BB in FIG. 24 in the sub-scanning direction Y. FIG. 24 to 26 show a portion of the thermal printhead (corresponding to one thermal printhead), and in this embodiment, this one thermal printhead is a piece-like thermal printhead 100A. . The thermal print head 100A includes a substrate 15 that is an insulator, a heat storage layer 33 on the substrate 15, a protective film 34A having grooves 38 on the heat storage layer 33, A plurality of embedded heating resistors 40, a common electrode 32 and a plurality of individual electrodes 31 on the heating resistors 40 and the protective film 34A, a plurality of the heating resistors 40, the protective film 34A, the common electrode 32, and a protective film 34B covering the plurality of individual electrodes 31.

The thermal print head 100A according to this embodiment differs from the thermal print head 100 according to the first embodiment in that the individual electrodes 31 and the common electrode 32 are arranged on the heating resistors 40 and the protective film 34A. It is a point. In this embodiment, the description of the first embodiment is used for common points with the first embodiment, and different points are described below.

When the individual electrode 31 and the common electrode 32 are arranged on the heating resistor 40 and the protective film 34A, the individual electrode 31 and the common electrode 32 are arranged on the main surface of the heating resistor 40 (the surface on which the heat storage layer 33 is located). Since heat is generated on the side opposite to the side), the generated heat can be efficiently transferred to the print medium, so the printing performance of the thermal print head 100A can be improved.

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

As shown in FIGS. 27 to 29, first, the substrate 15 is prepared, and the heat storage layer 33 is formed on the substrate 15. As shown in FIGS. Next, a resist 36 is formed on the heat storage layer 33 . A heating resistor 40 will be formed later in the region where the resist 36 exists.

Next, as shown in FIGS. 30 to 32, a protective film 34A is formed on the heat storage layer 33 where the resist 36 is not provided.

Next, as shown in FIGS. 33 to 35, the resist 36 is removed by the baking process for forming the protective film 34A, and grooves 38 are formed in the protective film 34A. Resist 36 may be removed using an organic stripping process.

By forming the protective film 34A using the resist 36 in this manner, the grooves 38 can be easily formed in the protective film 34A without using an etchant such as hydrofluoric acid that requires careful handling. .

Next, as shown in FIGS. 36 to 38, a resistor paste that will become the heating resistor 40 (heating resistor portion 41) is formed so as to fill the groove portion 38. Next, as shown in FIG. Next, the heating resistor 40 (heating resistor portion 41) is formed by firing the resistor paste described above.

Next, as shown in FIGS. 24 to 26, a protective film 34B is formed. The protective film 34B is made of amorphous glass, for example. The protective film 34B is formed by printing a thick film of glass paste and then baking it.

Through the above steps, the thermal print head 100A of this embodiment can be manufactured.

According to this embodiment, since the heat generating resistor 40 is formed so as to be embedded in the groove 38, even if the protective film 34B is thin, the edge of the heat generating resistor 40 can be completely covered, and the thermal print head can be easily mounted. 100A printing performance can be improved. In addition, since the heating resistor 40 is formed in the groove 38 of the protective film 34A without forming a plurality of heating resistors by wet etching or the like based on one heating resistor, the pattern shape of each heating resistor can be changed. Defects can be reduced.

(Other embodiments)
As noted above, although one embodiment has been described, the discussion and drawings forming part of the disclosure are to be understood as illustrative and not limiting. Various alternative embodiments, implementations and operational techniques will become apparent to those skilled in the art from this disclosure. Thus, this embodiment includes various embodiments and the like that are not described here.

<Thermal printer>
Further, as shown in FIG. 39, the thermal print head (for example, the thermal print head 100) includes a substrate 15 (the heat storage layer 33 and the like on the substrate 15 are not shown), a connection substrate 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 adjacent to each other in the sub-scanning direction Y on the heat dissipation member 8 . A plurality of heating resistors 41 arranged in the main scanning direction X are formed on the substrate 15 . The heat generating resistor portion 41 is driven to selectively generate heat by the drive IC 7 mounted on the connection substrate 5 . The heating resistor section 41 prints on a printing medium 92 such as thermal paper that is pressed against the heating resistor section 41 by the platen roller 91 according to a print signal transmitted from the outside through the connector 59 .

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

The heat dissipation 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 dissipation member 8 . Metal such as aluminum can be used for the heat dissipation member 8, for example.

A conductor such as gold can be used for the wire 81, for example. There are a plurality of wires 81, some of which are bonded to electrically connect the driving IC 7 and each individual electrode. Some of the other wires 81 are bonded to connect the drive IC 7 and the connector 59 through the wiring layer of the connection board 5 .

For example, black resin can 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 driving IC 7 and the plurality of wires 81 and protects the driving IC 7 and the plurality of wires 81 . The connector 59 is fixed to the connection board 5 . The connector 59 is connected with wiring for supplying electric power to the thermal print head from outside the thermal print head and for controlling the drive IC 7 .

A thermal printer can comprise a thermal printhead as described above. A thermal printer prints on a print medium conveyed along the sub-scanning direction Y. As shown in FIG. Normally, the print medium is conveyed from the connector 59 side toward the heating resistor section 41 side. Print media include, for example, thermal paper for creating barcode sheets and receipts.

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

The main power supply circuit supplies power to the plurality of heating resistors 41 in the thermal print head 100 . The measuring circuit measures the resistance value of each of the plurality of heating resistors 41 . The measuring circuit measures the resistance value of each of the plurality of heating resistors 41, for example, when printing on a print medium is not performed. As a result, it is possible to check the life of the heat generating resistor 41 and the presence or absence of a malfunctioning heat generating resistor 41 . The control unit controls driving states of the main power supply circuit and the measurement circuit. The controller controls the energized state of each of the plurality of heating resistors 41 . The measuring circuit may be omitted.

Connector 59 is used to communicate with devices outside thermal printhead 100 . Through connector 59, thermal print head 100 is electrically connected to the main power supply circuit and the measurement circuit. The thermal printhead 100 is electrically connected to the controller via the connector 59 .

The drive IC 7 receives signals from the control section via the connector 59 . The driving IC 7 controls the energization state of each of the plurality of heating resistors 41 based on the signal received from the control section. Specifically, the drive IC 7 selectively energizes a plurality of individual electrodes to arbitrarily generate heat in any one of the plurality of heating resistor portions 41 .

Moreover, the thermal print head is not limited to the above-described configuration. For example, the configuration may be one in which the drive IC 7 is directly mounted on the substrate 15 without providing the connection substrate 5, or a configuration in which the wires 81 are not provided by flip-chip mounting. or a configuration in which the heat radiating member 8 is not provided.

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

During printing on a print medium, a potential v11 is applied from the main power supply circuit to the connector 59 as the potential V1. In this case, the plurality of heating resistors 41 are selectively energized to generate heat. By transferring the heat to the print medium, printing is performed on the print medium. As described above, when the potential v11 is applied from the main power supply circuit to the connector 59 as the potential V1, an energization path to each of the plurality of heating resistors 41 is secured.

When printing on the print medium is not performed, the resistance value of each heating resistor portion 41 is measured. During the measurement, no potential is applied to the connector 59 from the main power supply circuit. When measuring the resistance value of each heating resistor portion 41, a potential v12 is applied to the connector 59 from the measuring circuit as the potential V1. In this case, the plurality of heating resistors 41 are energized in order (for example, in order from the heating resistor 41 positioned at the end in the main scanning direction X). The measuring circuit measures the resistance value of each heating resistor 41 based on the value of the current flowing through the heating resistor 41 and the potential v12. As described above, when the potential v11 is applied from the main power supply circuit to the connector 59 as the potential V1, the energization path to each of the plurality of heating resistors 41 is substantially cut off. As a result, the resistance value of each heat generating resistor 41 can be measured more accurately by the measurement circuit, and the life of the heat generating resistor 41 and the presence or absence of a malfunctioning heat generating resistor 41 can be confirmed.

According to the above, it is possible to obtain a thermal printer that ensures good printing performance.

5 connection board 7 drive IC
8 Heat dissipation member 15 Substrate 30 Wiring layer 31 Individual electrode 32 Common electrode 33 Heat storage layers 34A, 34B Protective film 36 Resist 38 Groove 40 Heating resistor 40A Curved surface 41 Heating resistor 59 Connector 81 Wire 82 Resin portion 91 Platen roller 92 Print medium 100 , 100A thermal print head

Claims (18)

an insulator;
a heat storage layer disposed on the insulator;
a first protective film disposed on the heat storage layer and having a groove;
a heating resistor disposed on the heat storage layer and embedded in the groove;
an individual electrode electrically connected to the heating resistor;
a common electrode having comb teeth electrically connected to the heating resistor;
a second protective film covering the heating resistor and the first protective film,
The thermal print head, wherein the individual electrodes are separated from the comb teeth of the common electrode and face the comb teeth. 2. A thermal printhead according to claim 1, wherein said heat generating resistors are arranged on said individual electrodes and said comb tooth portion. 2. A thermal printhead according to claim 1, wherein said individual electrodes and said common electrode are arranged on said heating resistor and said first protective film. 4. Any one of claims 1 to 3, wherein a boundary surface between said heating resistor and said second protective film is closer to said insulator than a boundary surface between said first protective film and said second protective film. A thermal print head according to the paragraph. Of the main surface of the second protective film on the side opposite to the side on which the first protective film is located, a portion that overlaps with the heating resistor when viewed from the normal direction of the main surface is a flat surface. The thermal print head according to any one of claims 1 to 4, wherein 6. The thermal printhead according to claim 1, wherein a main surface of said heating resistor on a side where said second protective film is located has a concave curved surface. A thermal printhead according to any one of claims 1 to 6, wherein said insulator is a substrate. 8. The thermal printhead of claim 7, wherein said substrate is made of ceramic. A thermal printer comprising the thermal print head according to any one of claims 1 to 8. forming a heat storage layer on the insulator,
forming a common electrode having a comb tooth portion and an individual electrode on the heat storage layer;
forming a resist on the heat storage layer, the individual electrodes, and the comb teeth;
forming a first protective film having a groove using the resist;
forming a heating resistor electrically connected to the individual electrode and the common electrode in the groove;
forming a second protective film covering the heating resistor and the first protective film;
The method of manufacturing a thermal print head, wherein the individual electrodes are spaced apart from the comb teeth of the common electrode and face the comb teeth. forming a heat storage layer on the insulator,
forming a resist on the heat storage layer;
forming a first protective film having a groove using the resist;
forming a heating resistor in the groove;
forming a common electrode having a comb tooth portion and individual electrodes on the heating resistor and the first protective film;
forming a second protective film covering the heating resistor, the first protective film, the common electrode, and the individual electrodes;
The method of manufacturing a thermal print head, wherein the individual electrodes are spaced apart from the comb teeth of the common electrode and face the comb teeth. 12. The method of manufacturing a thermal print head according to claim 10, wherein said first protective film is formed by baking a material paste that will become said first protective film. The thermal print according to any one of claims 10 to 12, wherein the heating resistor is formed by embedding a resistor paste in the groove of the first protective film and firing the resistor paste. How the head is made. 14. The method of manufacturing a thermal printhead according to claim 10, wherein the heating resistor is formed by screen printing. 14. The method of manufacturing a thermal printhead according to claim 10, wherein the heating resistor is formed using a mask. 16. The method of manufacturing a thermal printhead according to claim 15, wherein said mask is a stencil mask. The first protective film is formed through a baking process,
17. The method of manufacturing a thermal printhead according to claim 10, wherein said resist is removed by one or more steps selected from the group consisting of said baking step and organic stripping step. 18. The method of manufacturing a thermal printhead according to claim 10, wherein the main surface of the heating resistor on the side where the second protective film is located has a concave curved surface.

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