Thermal print head

Abstract

To provide a thermal print head improved in energy efficiency at the time of performing printing on a printing medium.SOLUTION: A thermal print head 1 comprises a heating resistor 40, a first electrode, and a second electrode. The first electrode includes a base part and an extending part. The extending part includes a first belt-like portion and a second belt-like portion. A first width of the first belt-like portion is smaller than a second width of the base part in a connection part between the second belt-like portion and the base part. A third width of the second belt-like portion in the connection part between the second belt-like portion and the base part is smaller than the second width. A width of at least a portion of the second belt-like portion is below the first width. A length of the second belt-like portion is larger than a half of a difference between a length of the first belt-like portion and a width of the heating resistor 40.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to thermal printheads. [Background technology]

[0002] Japanese Patent Application Laid-Open No. 2019-98667 (Patent Document 1) discloses a thermal printhead including an insulating substrate, a glaze layer laminated on the insulating substrate, an electrode disposed on the glaze layer, and a heating resistor including a plurality of heating portions. The electrode includes a common electrode and a plurality of individual electrodes. Each of the plurality of heating portions is electrically connected to the common electrode and one of the plurality of individual electrodes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-98667 A [Summary]

[0004] It is an object of the present disclosure to provide a thermal printhead that is more energy efficient when printing on a print medium.

[0005] The thermal printhead of the present disclosure includes a heating resistor including a heating portion, a first electrode connected to the heating resistor, and a second electrode connected to the heating resistor. The heating portion is a portion of the heating resistor sandwiched between the first electrode and the second electrode. The first electrode includes a base and an extension extending from the base to the heating resistor. The extension includes a first stripe and a second stripe connected to the first stripe and the base. The first stripe is in contact with the heating resistor and overlaps the second electrode in the longitudinal direction of the heating resistor. The second stripe does not overlap the second electrode in the longitudinal direction of the heating resistor. The first width of the first stripe is smaller than the second width of the base at the connection between the second stripe and the base. The third width of the second stripe at the connection between the second stripe and the base is smaller than the second width. At least a portion of the width of the second stripe is equal to or smaller than the first width. The length of the second strip is greater than half the difference between the length of the first strip and the width of the heating resistor. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic partial enlarged plan view of a thermal printhead according to a first embodiment. [Diagram 2] FIG. 2 is a schematic enlarged partial cross-sectional view of the thermal printhead of the first embodiment taken along the cross-sectional line II-II shown in FIG. [Diagram 3] 3 is a schematic enlarged partial cross-sectional view of the thermal printhead of the first embodiment taken along the cross-sectional line III-III shown in FIG. [Figure 4] FIG. 4 is a flowchart showing the method for manufacturing the thermal printhead according to the first embodiment. [Diagram 5] FIG. 5 is a schematic partial enlarged plan view of a thermal printhead according to a modified example of the first embodiment. [Figure 6] FIG. 6 is a schematic partial enlarged cross-sectional view of a thermal printhead according to a modified example of the first embodiment. [Figure 7] FIG. 7 is a schematic partial enlarged cross-sectional view of a thermal printhead according to a modified example of the first embodiment. [Figure 8]FIG. 8 is a schematic partial enlarged plan view of the thermal printhead according to the second embodiment. [Figure 9] FIG. 9 is a schematic enlarged partial cross-sectional view of the thermal printhead of the second embodiment taken along the cross-sectional line IX-IX shown in FIG. [Figure 10] 10 is a schematic partial enlarged cross-sectional view of the thermal printhead of the second embodiment taken along the cross-sectional line XX shown in FIG.

[0007] The details of the embodiments of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are given the same reference numerals, and the description thereof will not be repeated. At least some of the configurations of the embodiments described below may be arbitrarily combined.

[0008] (Embodiment 1)

[0009] A thermal printhead 1 according to the first embodiment will be described with reference to Figures 1 to 3. The thermal printhead 1 comprises a substrate 10, a glaze layer 12, a wiring layer 15, a heating resistor 40, and a protective layer 45.

[0010] The substrate 10 has a main surface 11. The longitudinal direction of the substrate 10 in a plan view of the main surface 11 is the X direction. The X direction is the main scanning direction. The lateral direction of the substrate 10 in a plan view of the main surface 11 is the Y direction. The Y direction is the sub-scanning direction. The thickness direction of the substrate 10, which is perpendicular to the X and Y directions, is the Z direction. The main surface 11 is an end face of the substrate 10 in the thickness direction (Z direction). The substrate 10 is made of an insulating material such as alumina (Al2O3). The substrate 10 is made of, for example, ceramic.

[0011] The glaze layer 12 is disposed on the main surface 11 of the substrate 10. The glaze layer 12 can accumulate heat generated from the heating resistor 40. The glaze layer 12 is formed of an insulating material such as glass.

[0012] The wiring layer 15 is disposed on the glaze layer 12. The wiring layer 15 is formed of a conductive material such as silver (Ag) or gold (Au). The wiring layer 15 includes a common electrode 20 and a plurality of individual electrodes 30. The common electrode 20 and the plurality of individual electrodes 30 are connected to a heating resistor 40.

[0013] Specifically, the common electrode 20 includes a base 21 and a plurality of extension portions 22. The base 21 extends along the X direction, and the longitudinal direction of the base 21 is the X direction. The base 21 is spaced apart from the heating resistor 40 in the Y direction. Each of the plurality of extension portions 22 extends from a side of the base 21 facing the heating resistor 40 toward the heating resistor 40. The longitudinal direction of each of the plurality of extension portions 22 is, for example, the Y direction. The plurality of extension portions 22 are arranged at intervals along the X direction.

[0014] Each of the extensions 22 includes a first strip portion 23 and a second strip portion 24. The first strip portion 23 is in contact with the heating resistor 40. The first strip portion 23 overlaps the individual electrode 30 (specifically, the first strip portion 33) in the longitudinal direction (X direction) of the heating resistor 40. That is, the first strip portion 23 is located within a region obtained by extending the first strip portion 33 adjacent to the first strip portion 23 in the longitudinal direction of the heating resistor 40. The second strip portion 24 is connected to the first strip portion 23 and the base 21. The second strip portion 24 does not overlap the individual electrode 30 (specifically, the first strip portion 33) in the longitudinal direction of the heating resistor 40. That is, the second strip portion 24 is located outside the region obtained by extending the first strip portion 33 adjacent to the first strip portion 23 in the longitudinal direction of the heating resistor 40. The thickness of the second band 24 is equal to the thickness of the base portion 21. The thickness of the second band 24 may be equal to the thickness of the first band 23.

[0015] Width W of the first band portion 23 11 is the width W of the base 21 at the connection between the second band portion 24 and the base 21. 1b The width W of the second band portion 24 at the connection portion between the second band portion 24 and the base portion 21 is smaller than 12 is the width W of the base 21 at the connection between the second band portion 24 and the base 21. 1bThe width (e.g., W 12 ) is the width W of the first strip portion 23 11 In this embodiment, the entire second band portion 24 has a constant width W 12 and the second band portion 24 has an overall width W 12 is the width W of the first belt-shaped portion 23 11 is equal to.

[0016] In this specification, the width W of the first band portion 23 11 means the length of the first strip portion 23 in the short-side direction (X direction) of the extension 22 in a plan view of the main surface 11 of the substrate 10. 1b means the length of the base 21 in the longitudinal direction (X direction) of the heating resistor 40 at the connection between the second strip portion 24 and the base 21 in a plan view of the main surface 11 of the substrate 10. 12 means the length of second band-shaped portion 24 in the short-side direction (X-direction) of extension 22 at the connection portion between second band-shaped portion 24 and base portion 21 in a plan view of main surface 11 of substrate 10.

[0017] Length L of the first belt-shaped portion 23 11 The length L of the first belt-shaped portion 23 is set according to the positioning error of the heating resistor 40 during the manufacture of the thermal printhead 1. 11 The length L of the second strip portion 24 is, for example, 300 μm or more. 12 is the length L of the first belt-shaped portion 23 11 and the width W of the heating resistor 40. 12 In this specification, the length L of the first band-shaped portion 23 is, for example, 150 μm or more. 11 means the length of the first strip portion 23 in the longitudinal direction (Y direction) of the extension portion 22 in a plan view of the main surface 11 of the substrate 10. 12means the length of the second band-shaped portion 24 in the longitudinal direction (Y direction) of the extension portion 22 in a plan view of the main surface 11 of the substrate 10. The width W of the heating resistor 40 means the length of the heating resistor 40 in the short side direction (Y direction) of the heating resistor 40 in a plan view of the main surface 11 of the substrate 10.

[0018] The individual electrodes 30 are arranged at intervals along the X direction. Each of the individual electrodes 30 includes a base 31, an extension 32, and a pad 35. The base 31 is spaced apart from the heating resistor 40 in the Y direction. The base 31 is connected to the extension 32 and the pad 35. The extension 32 extends from a proximal end of the base 31 relative to the heating resistor 40 toward the heating resistor 40. The longitudinal direction of the extension 32 is, for example, the Y direction. The extension 32 is disposed between two adjacent extensions 22. That is, the extensions 22 and the extensions 32 are arranged alternately in the X direction.

[0019] The extension 32 includes a first strip portion 33 and a second strip portion 34. The first strip portion 33 is in contact with the heating resistor 40. The first strip portion 33 overlaps the common electrode 20 (specifically, the first strip portion 23) in the longitudinal direction (X direction) of the heating resistor 40. That is, the first strip portion 33 is located within a region obtained by extending the first strip portion 23 adjacent to the first strip portion 33 in the longitudinal direction of the heating resistor 40. The second strip portion 34 is connected to the first strip portion 33 and the base 31. The second strip portion 34 does not overlap the common electrode 20 (specifically, the first strip portion 23) in the longitudinal direction of the heating resistor 40. That is, the second strip portion 34 is located outside a region obtained by extending the first strip portion 23 adjacent to the first strip portion 33 in the longitudinal direction of the heating resistor 40. The thickness of the second band 34 is equal to the thickness of the base portion 31. The thickness of the second band 34 may be equal to the thickness of the first band 33.

[0020] Width W of the first band portion 33 21 is the width W of the base 31 at the connection between the second band portion 34 and the base 31. 2b The width W of the second band portion 34 at the connection between the second band portion 34 and the base portion 31 is smaller than 22is the width W of the base 31 at the connection between the second band portion 34 and the base 31. 2b The width (e.g., W 22 ) is the width W of the first band portion 33 21 In this embodiment, the entire second band portion 34 has a constant width W 22 and the second band portion 34 has an overall width W 22 is the width W of the first band portion 33 21 is equal to.

[0021] In this specification, the width W of the first band portion 33 21 means the length of the first strip portion 33 in the short-side direction (X direction) of the extension portion 32 in a plan view of the main surface 11 of the substrate 10. 2b The width W of the second strip portion 34 at the connection portion between the second strip portion 34 and the base portion 31 means the length of the base portion 31 in the longitudinal direction (X direction) of the heating resistor 40 in the plan view of the main surface 11 of the substrate 10. 22 means the length of second band-shaped portion 34 in the short-side direction (X-direction) of extension 32 at the connection portion between second band-shaped portion 34 and base portion 31 in a plan view of main surface 11 of substrate 10.

[0022] Length L of the first belt-shaped portion 33 21 The length L of the first belt-shaped portion 33 is set according to the positioning error of the heating resistor 40 during the manufacture of the thermal printhead 1. 21 is the length L of the first belt-shaped portion 23 11 The length L of the first strip portion 33 is equal to 21 The length L of the second strip portion 34 is, for example, 300 μm or more. 22 is the length L of the first belt-shaped portion 33 21 and the width W of the heating resistor 40. 22 In this specification, the length L of the first band-shaped portion 33 is, for example, 150 μm or more. 21means the length of the first strip portion 33 in the longitudinal direction (Y direction) of the extension portion 32 in a plan view of the main surface 11 of the substrate 10. 22 means the length of the second band-shaped portion 34 in the longitudinal direction (Y direction) of the extension portion 32 when the main surface 11 of the substrate 10 is viewed in plan.

[0023] The pad 35 is connected to the distal end of the base 31 from the heating resistor 40. A conductive wire (not shown) is bonded to the pad 35, which is connected to a terminal of a driver IC (not shown).

[0024] In a plan view of the main surface 11 of the substrate 10, the heating resistor 40 is disposed between the base 21 of the common electrode 20 and the bases 31 of the individual electrodes 30. The heating resistor 40 extends along the X direction, and the longitudinal direction of the heating resistor 40 is the X direction. The heating resistor 40 is disposed on the first strip portions 23, 33 and the glaze layer 12. In a plan view of the main surface 11 of the substrate 10, the heating resistor 40 overlaps the first strip portions 23, 33. The heating resistor 40 is formed of a material (e.g., ruthenium oxide) having a higher resistivity than the material constituting the individual electrodes 30 and the common electrode 20.

[0025] The heating resistor 40 includes a plurality of heating portions 41. In a plan view of the main surface 11 of the substrate 10, each of the plurality of heating portions 41 is a portion of the heating resistor 40 that is sandwiched between the common electrode 20 (specifically, the first strip-shaped portion 23) and an individual electrode 30 (specifically, the first strip-shaped portion 33).

[0026] A common potential (e.g., ground potential) is applied to the common electrode 20. A potential is applied to each of the individual electrodes 30 from a driver IC (not shown). As a result, a current flows through a heat generating portion 41 located between the first band-shaped portion 33 of the individual electrode 30 to which the potential is applied and the first band-shaped portion 23 of the common electrode 20 adjacent thereto, causing the heat generating portion 41 to generate heat. The heat from the heat generating portion 41 is transferred to a print medium such as thermal paper, and printing is performed on the print medium.

[0027] The protective layer 45 covers the wiring layer 15, the heating resistor 40, and the glaze layer 12. The protective layer 45 protects the heating resistor 40 and the like from wear, corrosion, oxidation, and the like. The protective layer 45 is made of an insulating material such as amorphous glass. An opening (not shown) is provided in the protective layer 45, and the pad 35 is exposed from the opening of the protective layer 45.

[0028] An example of a method for manufacturing the thermal printhead 1 of the present embodiment will be described with reference to FIG.

[0029] A glaze layer 12 is formed on a main surface 11 of a substrate 10 (S1). Specifically, a paste containing glass is applied onto the main surface 11 of the substrate 10 by screen printing or the like. The paste is dried and then fired to form the glaze layer 12.

[0030] A wiring layer 15 is formed on the glaze layer 12 (S2). The wiring layer 15 includes a common electrode 20 and a plurality of individual electrodes 30. Specifically, a metal layer (not shown) is formed on the glaze layer 12. The metal layer is formed by applying a paste containing a material for forming the metal layer, such as a resinate paste containing silver particles, onto the glaze layer 12 by screen printing or the like, and then baking the paste. The metal layer is then patterned by a lithography process to form the wiring layer 15. For example, a resist pattern is formed on the metal layer. The resist pattern is formed by applying a photosensitive resin material onto the metal layer, and exposing and developing the applied photosensitive resin material. The resist pattern has openings. The metal layer is exposed from the openings of the resist pattern. The resist pattern is used as a mask to etch the parts of the metal layer that are exposed from the resist pattern. In this way, the metal layer is patterned to become the wiring layer 15.

[0031] The heating resistor 40 is formed (S3). For example, a paste containing materials constituting the heating resistor 40 (for example, glass and ruthenium oxide particles) is applied onto the first strip-shaped portions 23, 33 and the glaze layer 12. The paste is fired. In this manner, the heating resistor 40 is formed.

[0032] The protective layer 45 is formed (S4). For example, a paste containing glass is applied onto the wiring layer 15, the heating resistor 40, and the glaze layer 12. The paste is fired. In this manner, the protective layer 45 is formed.

[0033] The laminate including the substrate 10, the glaze layer 12, the wiring layer 15, the heating resistor 40, and the protective layer 45 is singulated (S5). For example, the laminate is cut by irradiating the laminate with a laser beam. The laminate is singulated into a plurality of thermal printheads 1. In this manner, the thermal printheads 1 are obtained.

[0034] A modification of this embodiment will now be described.

[0035] Referring to FIG. 5, the width (e.g., W 12 ) is the width W of the first strip portion 23 11 The entire second band portion 24 has a constant width W in the longitudinal direction of the extension portion 22. 12 and the second band portion 24 has an overall width W 12 is the width W of the first belt-shaped portion 23 11 The width (e.g., W 22 ) is the width W of the first band portion 33 21 The entire second band portion 34 has a constant width W in the longitudinal direction of the extension portion 32. 22 and the second band portion 34 has an overall width W 22 is the width W of the first band portion 33 21 It may be smaller.

[0036] 6, the thickness of the second band-shaped portion 34 may be smaller than the thickness of the base portion 31. With reference to Fig. 7, the thickness of the second band-shaped portion 24 may be smaller than the thickness of the base portion 21. The extension portions 22, 32 may extend in a diagonal direction with respect to the longitudinal direction of the heating resistor 40.

[0037] The effects of the thermal printhead 1 of this embodiment will be described.

[0038] The thermal printhead 1 of this embodiment includes a heating resistor 40 including a heating portion 41, a first electrode (common electrode 20 or individual electrode 30) connected to the heating resistor 40, and a second electrode (individual electrode 30 or common electrode 20) connected to the heating resistor 40. The heating portion 41 is a portion of the heating resistor 40 that is sandwiched between the first electrode and the second electrode. The first electrode includes a base (base 21 or base 31) and an extension (extension 22 or extension 32) extending from the base to the heating resistor 40. The extension includes a first strip (first strip 23 or first strip 33) and a second strip (second strip 24 or second strip 34) connected to the first strip and the base. The first strip is in contact with the heating resistor 40 and overlaps with the second electrode in the longitudinal direction of the heating resistor 40. The second strip portion does not overlap the second electrode in the longitudinal direction of the heating resistor 40. 11 or W 21 ) is the second width (W 1b or W 2b ) is smaller than the third width (W 12 or W 22 ) is smaller than the second width of the base. 12 or W 22 The length (L) of the second belt portion is equal to or less than the first width. 12 or L 22 ) is the length of the first strip (L 11 or L 21 ) and the width W of the heating resistor 40.

[0039] This increases the thermal resistance of the second band-shaped portion (second band-shaped portion 24 or second band-shaped portion 34), reducing heat dissipation from the heating resistor 40 to the base (base 21 or base 31) of the first electrode (common electrode 20 or individual electrode 30) through the second band-shaped portion. This reduces the energy required to raise the heating resistor 40 to a target temperature. This improves the energy efficiency of the thermal printhead 1 when printing on a print medium.

[0040] The thermal printhead 1 of this embodiment includes a heating resistor 40 including a heating portion 41, a first electrode (common electrode 20 or individual electrode 30) connected to the heating resistor 40, and a second electrode (individual electrode 30 or common electrode 20) connected to the heating resistor 40. The heating portion 41 is a portion of the heating resistor 40 that is sandwiched between the first electrode and the second electrode. The first electrode includes a base (base 21 or base 31) and an extension (extension 22 or extension 32) extending from the base to the heating resistor 40. The extension includes a first strip (first strip 23 or first strip 33) and a second strip (second strip 24 or second strip 34) connected to the first strip and the base. The first strip is in contact with the heating resistor 40 and overlaps with the second electrode in the longitudinal direction of the heating resistor 40. The second strip portion does not overlap the second electrode in the longitudinal direction of the heating resistor 40. 11 or W 21 ) is the second width (W 1b or W 2b ) is smaller than the third width (W 12 or W 22 ) is smaller than the second width. 12 or W 22 ) is smaller than the first width.

[0041] This increases the thermal resistance of the second band-shaped portion (second band-shaped portion 24 or second band-shaped portion 34), reducing heat dissipation from the heating resistor 40 to the base (base 21 or base 31) of the first electrode (common electrode 20 or individual electrode 30) through the second band-shaped portion. This reduces the energy required to raise the heating resistor 40 to a target temperature. This improves the energy efficiency of the thermal printhead 1 when printing on a print medium.

[0042] In thermal printhead 1 of this embodiment, the thickness of the second band-shaped portion (second band-shaped portion 24 or second band-shaped portion 34) is smaller than the thickness of the base portion (base portion 21 or base portion 31).

[0043] This further increases the thermal resistance of the second band-shaped portion (second band-shaped portion 24 or second band-shaped portion 34), and further reduces heat dissipation from the heating resistor 40 to the base (base 21 or base 31) of the first electrode (common electrode 20 or individual electrode 30) through the second band-shaped portion. This reduces the energy required to raise the heating resistor 40 to a target temperature. This improves the energy efficiency of the thermal printhead 1 when printing on a print medium.

[0044] In the thermal printhead 1 of this embodiment, the first electrode is an individual electrode 30 and the second electrode is a common electrode 20.

[0045] This further increases the thermal resistance of the second band-shaped portion 34, and further reduces the dissipation of heat from the heating resistor 40 to the base 31 of the individual electrode 30, etc., through the second band-shaped portion 34. This reduces the energy required to raise the heating resistor 40 to a target temperature. This improves the energy efficiency of the thermal printhead 1 when printing on a print medium.

[0046] In the thermal printhead 1 of this embodiment, the first electrode is a common electrode 20 and the second electrode is an individual electrode 30.

[0047] This further increases the thermal resistance of the second band-shaped portion 24, and further reduces the dissipation of heat from the heating resistor 40 to the base 21 of the common electrode 20 and the like through the second band-shaped portion 24. This reduces the energy required to raise the heating resistor 40 to the target temperature. This improves the energy efficiency of the thermal printhead 1 when printing on a print medium.

[0048] (Embodiment 2)

[0049] The thermal printhead 1 of the second embodiment will be described with reference to Figures 8 to 10. The thermal printhead 1 of the present embodiment has a similar configuration to the thermal printhead 1 of the first embodiment, but differs from it mainly in the following points.

[0050] The outer width W of the second band portion 24 in this embodiment 13 is larger than the outer width of the second band portion 24 in the first embodiment. In the present embodiment, the outer width W 13 is the width W of the first belt-shaped portion 23 11 and the width W of the base 21 at the connection between the second band portion 24 and the base 21 is greater than 1b Less than.

[0051] An insulating region 26 is provided on the inside of the second band-shaped portion 24. The insulating region 26 is a region where the common electrode 20 is not formed. The insulating region 26 is formed, for example, by removing a part of the metal layer in the step (S2) of forming the wiring layer 15 shown in FIG. 4. The insulating region 26 may extend to the connection portion between the second band-shaped portion 24 and the base portion 21.

[0052] The width of a portion of the second band portion 24 (for example, W 12 ) is the width W of the base 21 at the connection between the second strip portion 24 and the base 21 1b The width W of the first band portion 23 is smaller than the width W of the first band portion 23. 11 The width of a portion of the second band 24 (e.g., W 12 ) is the width w 11 and width w 12The width w 11 is the width of the portion of the second strip portion 24 on one side of the insulating region 26 in the arrangement direction (X direction) of the multiple extension portions 22. 12 is the width of the portion of the second strip portion 24 that is on the other side of the insulating region 26 in the arrangement direction of the multiple extension portions 22 (X direction).

[0053] The outer width W of the second band portion 34 in this embodiment 23 is larger than the outer width of the second band portion 34 in the first embodiment. In the present embodiment, the outer width W 23 is the width W of the first band portion 33 21 and the width W of the base 31 at the connection between the second band portion 34 and the base 31 is greater than 2b is equal to.

[0054] An insulating region 36 is provided on the inside of the second band-shaped portion 34. The insulating region 36 is a region where the individual electrodes 30 are not formed. The insulating region 36 is formed, for example, by removing a part of the metal layer in the step (S2) of forming the wiring layer 15 shown in FIG. 4. The insulating region 36 may extend to the connection portion between the second band-shaped portion 34 and the base portion 31.

[0055] The width of a portion of the second band portion 34 (for example, W 22 ) is the width W of the base 31 at the connection between the second strip portion 24 and the base 21 2b The width W of the first band portion 33 is smaller than the width W of the first band portion 33. 21 The width of a portion of the second band 34 (e.g., W 22 ) is the width w 21 and width w 22 The width w 21 is the width of the portion of the second strip portion 34 on one side of the insulating region 36 in the arrangement direction (X direction) of the multiple extension portions 32. 22 is the width of the portion of the second strip portion 34 that is on the other side of the insulating region 36 in the arrangement direction of the multiple extension portions 32 (X direction).

[0056] The thermal printhead 1 of this embodiment has the following advantages similar to those of the thermal printhead 1 of the first embodiment.

[0057] In the thermal printhead 1 of this embodiment, an insulating region (insulating region 26 or insulating region 36) is provided inside at least a portion of the second band-shaped portion (second band-shaped portion 24 or second band-shaped portion 34).

[0058] This increases the thermal resistance of the second band-shaped portion (second band-shaped portion 24 or second band-shaped portion 34), reducing heat dissipation from the heating resistor 40 to the base (base 21 or base 31) of the first electrode (common electrode 20 or individual electrode 30) through the second band-shaped portion. This reduces the energy required to raise the heating resistor 40 to a target temperature. This improves the energy efficiency of the thermal printhead 1 when printing on a print medium.

[0059] Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) A heating resistor including a heating portion; A first electrode connected to the heating resistor; a second electrode connected to the heating resistor; the heat generating portion is a portion of the heat generating resistor that is sandwiched between the first electrode and the second electrode, the first electrode includes a base and an extension extending from the base to the heating resistor, the extension including a first strip and a second strip connected to the first strip and the base; the first strip portion is in contact with the heating resistor and overlaps with the second electrode in a longitudinal direction of the heating resistor; the second strip portion does not overlap the second electrode in the longitudinal direction of the heating resistor, a first width of the first band portion is smaller than a second width of the base portion at a connection portion between the second band portion and the base portion; a third width of the second band portion at the connection portion is smaller than the second width; a width of at least a portion of the second band portion is equal to or smaller than the first width; A thermal printhead, wherein the length of the second band-shaped portion is greater than half the difference between the length of the first band-shaped portion and the width of the heating resistor. (Appendix 2) A heating resistor including a heating portion; A first electrode connected to the heating resistor; a second electrode connected to the heating resistor; the heat generating portion is a portion of the heat generating resistor that is sandwiched between the first electrode and the second electrode, the first electrode includes a base and an extension extending from the base to the heating resistor, the extension including a first strip and a second strip connected to the first strip and the base; the first strip portion is in contact with the heating resistor and overlaps with the second electrode in a longitudinal direction of the heating resistor; the second strip portion does not overlap the second electrode in the longitudinal direction of the heating resistor, a first width of the first band portion is smaller than a second width of the base portion at a connection portion between the second band portion and the base portion; a third width of the second band portion at the connection portion is smaller than the second width; A thermal printhead, wherein at least a portion of the second band has a width smaller than the first width. (Appendix 3) A thermal printhead as described in Appendix 1, wherein an insulating region is provided inside at least a portion of the second band-shaped portion. (Appendix 4) A thermal printhead as described in Appendix 2, wherein an insulating region is provided inside at least a portion of the second band-shaped portion. (Appendix 5) 4. The thermal printhead of claim 1, wherein the second band portion has a thickness smaller than a thickness of the base portion. (Appendix 6) 5. The thermal printhead of claim 2, wherein the second band portion has a thickness smaller than a thickness of the base portion. (Appendix 7) the first electrode is an individual electrode, 7. The thermal printhead of claim 1, wherein the second electrode is a common electrode. (Appendix 8) the first electrode is a common electrode, 7. The thermal printhead of claim 1, wherein the second electrode is an individual electrode.

[0060] The first and second embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is indicated by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0061] 1 thermal print head, 10 substrate, 11 main surface, 12 glaze layer, 15 wiring layer, 20 common electrode, 21, 31 base portion, 22, 32 extension portion, 23, 33 first strip portion, 24, 34 second strip portion, 26, 36 insulating region, 30 individual electrode, 35 pad, 40 heating resistor, 41 heating portion, 45 protective layer.

Claims

1. A heating resistor including a heating portion; A first electrode connected to the heating resistor; a second electrode connected to the heating resistor; the heat generating portion is a portion of the heat generating resistor that is sandwiched between the first electrode and the second electrode, the first electrode includes a base and an extension extending from the base to the heating resistor, the extension including a first strip and a second strip connected to the first strip and the base; the first strip portion is in contact with the heating resistor and overlaps with the second electrode in a longitudinal direction of the heating resistor, the second strip portion does not overlap the second electrode in the longitudinal direction of the heating resistor, a first width of the first band portion is smaller than a second width of the base portion at a connection portion between the second band portion and the base portion; a third width of the second band portion at the connection portion is smaller than the second width; a width of at least a portion of the second band portion is equal to or smaller than the first width; A thermal printhead, wherein the length of the second band-shaped portion is greater than half the difference between the length of the first band-shaped portion and the width of the heating resistor.

2. A heating resistor including a heating portion; A first electrode connected to the heating resistor; a second electrode connected to the heating resistor; the heat generating portion is a portion of the heat generating resistor that is sandwiched between the first electrode and the second electrode, the first electrode includes a base and an extension extending from the base to the heating resistor, the extension including a first strip and a second strip connected to the first strip and the base; the first strip portion is in contact with the heating resistor and overlaps with the second electrode in a longitudinal direction of the heating resistor, the second strip portion does not overlap the second electrode in the longitudinal direction of the heating resistor, a first width of the first band portion is smaller than a second width of the base portion at a connection portion between the second band portion and the base portion; a third width of the second band portion at the connection portion is smaller than the second width; A thermal printhead, wherein at least a portion of the second band has a width smaller than the first width.

3. The thermal printhead of claim 1 , further comprising an insulating region disposed inside at least a portion of the second band.

4. The thermal printhead of claim 2 , further comprising an insulating region disposed inside at least a portion of the second band.

5. The thermal printhead of claim 1 , wherein the second band has a thickness less than a thickness of the base.

6. The thermal printhead of claim 2 , wherein the second band has a thickness less than a thickness of the base.

7. the first electrode is an individual electrode, The thermal printhead of claim 1 , wherein the second electrode is a common electrode.

8. the first electrode is a common electrode, The thermal printhead of claim 1 , wherein the second electrode is a discrete electrode.

Images