Thermal printing head

Abstract

The present disclosure addresses the problem of providing a thermal print head that improves energy efficiency when printing on a print medium. A thermal print head according to the present disclosure includes a heat generating resistor, a first electrode, and a second electrode. The first electrode includes a base portion and an extension portion. The extension portion includes a first band-shaped portion and a second band-shaped portion. A first width of the first band-shaped portion is smaller than a second width of the base portion at a connection portion between the second band-shaped portion and the base portion. A third width of the second band-shaped portion at a connection portion between the second band-shaped portion and the base portion is smaller than the second width. The width of at least a portion of the second band-shaped portion is equal to or less than the first width. The length of the second band-shaped portion is greater than half of the difference between the length of the first band-shaped portion and the width of the heating resistor.

Description

Technical Field

[0001] The present disclosure relates to a thermal print head. Background Art

[0002] Japanese Patent Publication No. 2019-98667 (Patent Document 1) discloses a thermal print head, comprising: 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. The plurality of heating portions are respectively connected to the common electrode and one of the plurality of individual electrodes.

[0003] [Prior art literature]

[0004] [Patent Document]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-98667 Summary of the invention

[0006] An object of the present disclosure is to provide a thermal print head having improved energy efficiency when printing on a print medium.

[0007] The thermal print head disclosed in the present invention comprises: 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 by 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 strip portion and a second strip portion connected to the first strip portion and the base. The first strip portion contacts the heating resistor and overlaps with the second electrode in the long side direction of the heating resistor. The second strip portion does not overlap with the second electrode in the long side direction of the heating resistor. The first width of the first strip portion is smaller than the second width of the base at the connection between the second strip portion and the base. The third width of the second strip portion at the connection between the second strip portion and the base is smaller than the second width. The width of at least a portion of the second strip portion is less than the first width. The length of the second strip portion is greater than half of the difference between the length of the first strip portion and the width of the heating resistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a schematic partially enlarged top view of the thermal print head according to the first embodiment.

[0009] Figure 2 The thermal print head of embodiment 1 is Figure 1 A schematic partial enlarged cross-sectional view along section line II-II is shown.

[0010] Figure 3 The thermal print head of embodiment 1 is Figure 1A schematic partial enlarged cross-sectional view along section line III-III is shown.

[0011] Figure 4 This is a diagram showing a flow chart of the method for manufacturing the thermal print head according to the first embodiment.

[0012] Figure 5 This is a schematic partially enlarged plan view of a thermal print head according to a modified example of the first embodiment.

[0013] Figure 6 This is a schematic partially enlarged cross-sectional view of a thermal print head according to a modified example of the first embodiment.

[0014] Figure 7 This is a schematic partially enlarged cross-sectional view of a thermal print head according to a modified example of the first embodiment.

[0015] Figure 8 This is a schematic partially enlarged top view of the thermal print head according to the second embodiment.

[0016] Fig. 9 The thermal print head of Embodiment 2 is Figure 8 A schematic partial enlarged cross-sectional view along section line IX-IX is shown.

[0017] Fig.10 The thermal print head of Embodiment 2 is Figure 8 A schematic partial enlarged cross-sectional view along section line XX is shown. DETAILED DESCRIPTION

[0018] Based on the drawings, the details of the embodiments of the present disclosure are described. In addition, the same reference numbers are marked on the same or equivalent parts in the following drawings, and their descriptions are not repeated. It is also possible to arbitrarily combine at least a part of the embodiments described below.

[0019] (Implementation Method 1)

[0020] Reference Figures 1 to 3 Next, the thermal print head 1 of Embodiment 1 is described. The thermal print head 1 includes a substrate 10 , a glaze layer 12 , a wiring layer 15 , a heating resistor 40 , and a protective layer 45 .

[0021] The substrate 10 has a main surface 11. The long side direction of the substrate 10 when looking down on the main surface 11 is set to the X direction. The X direction is the main scanning direction. The short side direction of the substrate 10 when looking down on the main surface 11 is set to the Y direction. The Y direction is the sub-scanning direction. The thickness direction of the substrate 10 perpendicular to the X direction and the Y direction is set to the Z direction. The main surface 11 is an end surface in the thickness direction (Z direction) of the substrate 10. The substrate 10 is formed of an insulating material such as aluminum oxide (Al2O3). The substrate 10 is formed of ceramics, for example.

[0022] The glaze layer 12 is disposed on the main surface 11 of the substrate 10. The glaze layer 12 can store heat generated by the heating resistor 40. The glaze layer 12 is formed of an insulating material such as glass.

[0023] 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 the heating resistor 40.

[0024] Specifically, the common electrode 20 includes a base 21 and a plurality of extensions 22. The base 21 extends in the X direction, and the long side direction of the base 21 is the X direction. The base 21 is spaced apart from the heating resistor 40 in the Y direction. The plurality of extensions 22 extend from the sides of the base 21 facing the heating resistor 40 toward the heating resistor 40. The long side direction of each of the plurality of extensions 22 is, for example, the Y direction. The plurality of extensions 22 are arranged at intervals in the X direction.

[0025] The plurality of extension portions 22 include a first strip portion 23 and a second strip portion 24, respectively. The first strip portion 23 contacts the heating resistor 40. The first strip portion 23 does not overlap with the individual electrode 30 (specifically, the first strip portion 33) in the long side direction (X direction) of the heating resistor 40. That is, the first strip portion 23 is located in a region obtained by extending the first strip portion 33 adjacent to the first strip portion 23 along the long side 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 with the individual electrode 30 (specifically, the first strip portion 33) in the long side direction of the heating resistor 40. That is, the second strip portion 24 is located outside of a region obtained by extending the first strip portion 33 adjacent to the first strip portion 23 along the long side direction of the heating resistor 40. The thickness of the second strip portion 24 is equal to the thickness of the base 21. The thickness of the second strip-shaped portion 24 may be equal to the thickness of the first strip-shaped portion 23 .

[0026] The width W of the first strip-shaped portion 23 11 smaller than the width W of the base 21 at the connection between the second strip-shaped portion 24 and the base 21 1b The width W of the second strip-shaped portion 24 at the connection portion between the second strip-shaped portion 24 and the base portion 21 is 12 smaller than the width W of the base 21 at the connection between the second strip-shaped portion 24 and the base 21 1b The width of at least a portion of the second strip-shaped portion 24 (eg, W 12 ) and the width W of the first strip-shaped portion 23 11 In this embodiment, the second strip-shaped portion 24 as a whole has a constant width W in the longitudinal direction of the extending portion 22. 12The width W of the second strip portion 24 is 12 The width W of the first strip-shaped portion 23 11 equal.

[0027] In this specification, the width W of the first strip-shaped portion 23 is 11 It refers to the length of the first strip-shaped portion 23 in the short-side direction (X direction) of the extension portion 22 when the main surface 11 of the substrate 10 is viewed from above. The width W of the base portion 21 at the connection between the second strip-shaped portion 24 and the base portion 21 is 1b The width W of the second strip-shaped portion 24 at the connection between the second strip-shaped portion 24 and the base portion 21 is the length of the base portion 21 in the longitudinal direction (X direction) of the heating resistor 40 when the main surface 11 of the substrate 10 is viewed from above. 12 It refers to the length of the second strip-shaped portion 24 in the short-side direction (X direction) of the extending portion 22 at the connection portion between the second strip-shaped portion 24 and the base portion 21 when the principal surface 11 of the substrate 10 is viewed in plan.

[0028] The length L of the first strip-shaped portion 23 11 The length L of the first strip-shaped portion 23 is set according to the arrangement error of the heating resistor 40 when the thermal print head 1 is manufactured. 11 For example, the length L of the second strip-shaped portion 24 is 300 μm or more. 12 Greater than the length L of the first strip-shaped portion 23 11 The length L of the second strip-shaped portion 24 is half the difference between the width W of the heating resistor 40 and the width W of the heating resistor 40. 12 For example, it is 150 μm or more. In this specification, the length L of the first strip-shaped portion 23 is 11 It refers to the length of the first strip-shaped portion 23 in the longitudinal direction (Y direction) of the extension portion 22 when the main surface 11 of the substrate 10 is viewed from above. The length L of the second strip-shaped portion 24 12 It refers to the length of the second strip-shaped portion 24 in the long side direction (Y direction) of the extension portion 22 when looking down at the main surface 11 of the substrate 10. The width W of the heating resistor 40 refers to the length of the heating resistor 40 in the short side direction (Y direction) of the heating resistor 40 when looking down at the main surface 11 of the substrate 10.

[0029] The plurality of individual electrodes 30 are arranged at intervals along the X direction. The plurality of individual electrodes 30 respectively include 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 the proximal end of the base 31 close to the heating resistor 40 toward the heating resistor 40. The long side direction of the extension 32 is, for example, the Y direction. The extension 32 is arranged between two adjacent extensions 22. That is, the extension 22 and the extension 32 are arranged alternately in the X direction.

[0030] The extension portion 32 includes a first strip-shaped portion 33 and a second strip-shaped portion 34. The first strip-shaped portion 33 contacts the heating resistor 40. The first strip-shaped portion 33 overlaps with the common electrode 20 (specifically, the first strip-shaped portion 23) in the long-side direction (X direction) of the heating resistor 40. That is, the first strip-shaped portion 33 is located in a region obtained by extending the first strip-shaped portion 23 adjacent to the first strip-shaped portion 33 along the long-side direction of the heating resistor 40. The second strip-shaped portion 34 is connected to the first strip-shaped portion 33 and the base 31. The second strip-shaped portion 34 does not overlap with the common electrode 20 (specifically, the first strip-shaped portion 23) in the long-side direction of the heating resistor 40. That is, the second strip-shaped portion 34 is located outside the region obtained by extending the first strip-shaped portion 23 adjacent to the first strip-shaped portion 33 along the long-side direction of the heating resistor 40. The thickness of the second strip-shaped portion 34 is equal to the thickness of the base 31. The thickness of the second strip-shaped portion 34 may be equal to the thickness of the first strip-shaped portion 33 .

[0031] The width W of the first strip-shaped portion 33 21 smaller than the width W of the base portion 31 at the connection between the second strip portion 34 and the base portion 31 2b The width W of the second strip-shaped portion 34 at the connection portion between the second strip-shaped portion 34 and the base portion 31 is 22 smaller than the width W of the base portion 31 at the connection between the second strip portion 34 and the base portion 31 2b The width of at least a portion of the second strip-shaped portion 34 (eg, W 22 ) and the width W of the first strip-shaped portion 33 21 In this embodiment, the second strip-shaped portion 34 has a constant width W in the longitudinal direction of the extending portion 32 as a whole. 22 The width W of the second strip portion 34 is 22 The width W of the first strip-shaped portion 33 21 equal.

[0032] In this specification, the width W of the first strip-shaped portion 33 is 21 It refers to the length of the first strip-shaped portion 33 in the short-side direction (X direction) of the extension portion 32 when the main surface 11 of the substrate 10 is viewed from above. The width W of the base portion 31 at the connection portion between the second strip-shaped portion 34 and the base portion 31 is 2b The width W refers to the length of the base 31 at the connection between the second strip-shaped portion 34 and the base 31 in the long side direction (X direction) of the heating resistor 40 when looking down at the main surface 11 of the substrate 10. The width W of the second strip-shaped portion 34 at the connection between the second strip-shaped portion 34 and the base 31 is 22 It refers to the length of the second strip-shaped portion 34 in the short-side direction (X direction) of the extending portion 32 at the connection portion between the second strip-shaped portion 34 and the base portion 31 when the principal surface 11 of the substrate 10 is viewed in plan.

[0033] The length L of the first strip-shaped portion 33 21 The length L of the first strip-shaped portion 33 is set according to the arrangement error of the heating resistor 40 when manufacturing the thermal print head 1. 21 The length L of the first strip portion 23 11 The length L of the first strip-shaped portion 33 is equal to 21 For example, the length L of the second strip-shaped portion 34 is 300 μm or more. 22 Greater than the length L of the first strip-shaped portion 33 21 The length L of the second strip-shaped portion 34 is half the difference between the width W of the heating resistor 40 and the width W of the heating resistor 40. 22 For example, it is 150 μm or more. In this specification, the length L of the first strip-shaped portion 33 is 21 It refers to the length of the first strip-shaped portion 33 in the longitudinal direction (Y direction) of the extension portion 32 when the main surface 11 of the substrate 10 is viewed from above. The length L of the second strip-shaped portion 34 is 22 It refers to the length of the second strip-shaped portion 34 in the longitudinal direction (Y direction) of the extending portion 32 when the main surface 11 of the substrate 10 is viewed in plan.

[0034] The pad 35 is connected to the end of the base 31 far from the heating resistor 40. A conductive wire (not shown) connected to a terminal of a driver IC (Integrated Circuit) (not shown) is bonded to the pad 35.

[0035] When the main surface 11 of the substrate 10 is viewed from above, the heating resistor 40 is arranged between the base 21 of the common electrode 20 and the base 31 of the plurality of individual electrodes 30. The heating resistor 40 extends in the X direction, and the long side direction of the heating resistor 40 is the X direction. The heating resistor 40 is arranged on the first strip-shaped portions 23, 33 and the glaze layer 12. When the main surface 11 of the substrate 10 is viewed from above, the heating resistor 40 overlaps with the first strip-shaped portions 23, 33. The heating resistor 40 is formed of a material having a higher resistivity than the material constituting the individual electrodes 30 and the common electrode 20 (for example, ruthenium oxide).

[0036] The heating resistor 40 includes a plurality of heating portions 41. The plurality of heating portions 41 are portions of the heating resistor 40 sandwiched between the common electrode 20 (specifically, the first strip-shaped portion 23) and the individual electrode 30 (specifically, the first strip-shaped portion 33) when the main surface 11 of the substrate 10 is viewed in plan.

[0037] A common potential (for example, a ground potential) is applied to the common electrode 20. A potential is applied to each of the plurality of individual electrodes 30 from a driving IC (not shown). As a result, a current flows through the heat generating portion 41 between the individual electrode 30 to which the potential is applied, that is, the first strip-shaped portion 33 and the common electrode 20 adjacent thereto, that is, the first strip-shaped portion 23, so that the heat generating portion 41 generates heat. The heat from the heat generating portion 41 is transferred to a printing medium such as thermal paper, so that printing can be performed on the printing medium.

[0038] 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 or oxidation. The protective layer 45 is formed 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.

[0039] Reference Figure 4 , an example of a method for manufacturing the thermal print head 1 of the present embodiment will be described.

[0040] The glaze layer 12 is formed on the main surface 11 of the substrate 10 (S1). Specifically, a paste containing glass is applied to the main surface 11 of the substrate 10 by screen printing or the like. The glaze layer 12 is formed by drying the paste and then firing it.

[0041] 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, for example, by the following method: a slurry containing a material constituting the metal layer, such as a resinate slurry containing silver particles, is applied to the glaze layer 12 by screen printing or the like, and then the slurry is calcined. Next, the metal layer is patterned by a photolithography step 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 to the metal layer and exposing and developing the applied photosensitive resin material. The resist pattern has an opening. The metal layer is exposed from the opening of the resist pattern. The resist pattern is used as a mask to etch the portion of the metal layer exposed from the resist pattern. In this way, the metal layer is patterned to form the wiring layer 15.

[0042] The heating resistor 40 is formed (S3). For example, a slurry containing a material constituting the heating resistor 40 (eg, glass and ruthenium oxide particles) is applied onto the first band-shaped portions 23 and 33 and the glaze layer 12. The slurry is fired. In this way, the heating resistor 40 is formed.

[0043] The protective layer 45 is formed (S4). For example, a paste containing glass is applied to the wiring layer 15, the heating resistor 40, and the glaze layer 12. The paste is fired. In this way, the protective layer 45 is formed.

[0044] The laminated body 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 laminated body is irradiated with laser light to cut the laminated body. The laminated body is singulated into a plurality of thermal print heads 1. In this way, the thermal print head 1 is obtained.

[0045] Modifications of this embodiment will be described.

[0046] Reference Figure 5 , the width of at least a portion of the second strip-shaped portion 24 (eg, W 12 ) may be smaller than the width W of the first strip-shaped portion 23. 11 The second strip-shaped portion 24 as a whole may have a certain width W in the longitudinal direction of the extending portion 22. 12 The width W of the second strip portion 24 is 12 It may be smaller than the width W of the first strip-shaped portion 23. 11 The width of at least a portion of the second strip-shaped portion 34 (eg, W 22 ) may also be smaller than the width W of the first strip-shaped portion 33 21 The second strip-shaped portion 34 as a whole may have a certain width W in the longitudinal direction of the extending portion 32. 22 The width W of the second strip portion 34 is 22 It may be smaller than the width W of the first strip-shaped portion 33. 21 .

[0047] Reference Figure 6 , the thickness of the second strip-shaped portion 34 may also be smaller than the thickness of the base portion 31. Figure 7 The thickness of the second strip-shaped portion 24 may be smaller than the thickness of the base portion 21. The extension portions 22 and 32 may extend in a direction inclined with respect to the longitudinal direction of the heating resistor 40.

[0048] The effects of the thermal print head 1 of this embodiment will be described.

[0049] The thermal print head 1 of this embodiment includes: a heating resistor 40 including a heating portion 41; a first electrode (a common electrode 20 or a separate electrode 30) connected to the heating resistor 40; and a second electrode (a separate electrode 30 or a common electrode 20) connected to the heating resistor 40. The heating portion 41 is a portion of the heating resistor 40 sandwiched by the first electrode and the second electrode. The first electrode includes a base (a base 21 or a base 31) and an extension (an extension 22 or an extension 32) extending from the base to the heating resistor 40. The extension includes a first strip-shaped portion (a first strip-shaped portion 23 or a first strip-shaped portion 33) and a second strip-shaped portion (a second strip-shaped portion 24 or a second strip-shaped portion 34) connected to the first strip-shaped portion and the base. The first strip-shaped portion contacts the heating resistor 40 and overlaps with the second electrode in the long side direction of the heating resistor 40. The second strip-shaped portion does not overlap with the second electrode in the long side direction of the heating resistor 40. The first width (W 11 or W 21 ) is smaller than the second width (W 1b or W 2b The third width (W ) of the second strip-shaped portion at the connection portion between the second strip-shaped portion and the base portion 12 or W 22 ) is smaller than the second width of the base. The width of at least a portion of the second strip-shaped portion (e.g., W 12 or W 22 ) is less than the first width. The length of the second strip-shaped portion (L 12 or L 22 ) is greater than the length of the first strip portion (L 11 or L 21 ) is half the difference between the width W of the heating resistor 40.

[0050] Therefore, the thermal resistance of the second strip-shaped portion (the second strip-shaped portion 24 or the second strip-shaped portion 34) increases, and the heat dissipation from the heating resistor 40 through the second strip-shaped portion toward the base (base 21 or base 31) of the first electrode (common electrode 20 or individual electrode 30) is reduced. The energy required to raise the heating resistor 40 to the target temperature is reduced. The energy efficiency of the thermal print head 1 when printing on the printing medium can be improved.

[0051] The thermal print head 1 of this embodiment includes: a heating resistor 40 including a heating portion 41; a first electrode (a common electrode 20 or a separate electrode 30) connected to the heating resistor 40; and a second electrode (a separate electrode 30 or a common electrode 20) connected to the heating resistor 40. The heating portion 41 is a portion of the heating resistor 40 sandwiched by the first electrode and the second electrode. The first electrode includes a base (a base 21 or a base 31) and an extension (an extension 22 or an extension 32) extending from the base to the heating resistor 40. The extension includes a first strip-shaped portion (a first strip-shaped portion 23 or a first strip-shaped portion 33) and a second strip-shaped portion (a second strip-shaped portion 24 or a second strip-shaped portion 34) connected to the first strip-shaped portion and the base. The first strip-shaped portion contacts the heating resistor 40 and overlaps with the second electrode in the long side direction of the heating resistor 40. The second strip-shaped portion does not overlap with the second electrode in the long side direction of the heating resistor 40. The first width (W 11 or W 21 ) is smaller than the second width (W 1b or W 2b The third width (W ) of the second strip-shaped portion at the connection portion between the second strip-shaped portion and the base portion 12 or W 22 ) is smaller than the second width. The width of at least a portion of the second strip-shaped portion (e.g., W 12 or W 22 ) is smaller than the first width.

[0052] Therefore, the thermal resistance of the second strip-shaped portion (the second strip-shaped portion 24 or the second strip-shaped portion 34) increases, and the heat dissipation from the heating resistor 40 through the second strip-shaped portion toward the base (base 21 or base 31) of the first electrode (common electrode 20 or individual electrode 30) is reduced. The energy required to raise the heating resistor 40 to the target temperature is reduced. The energy efficiency of the thermal print head 1 when printing on the printing medium can be improved.

[0053] In the thermal print head 1 of the present embodiment, the thickness of the second belt-shaped portion (the second belt-shaped portion 24 or the second belt-shaped portion 34 ) is smaller than the thickness of the base portion (the base portion 21 or the base portion 31 ).

[0054] Therefore, the thermal resistance of the second strip-shaped portion (the second strip-shaped portion 24 or the second strip-shaped portion 34) is further increased, and the heat dissipation from the heating resistor 40 through the second strip-shaped portion toward the base (base 21 or base 31) of the first electrode (common electrode 20 or individual electrode 30) is further reduced. The energy required to raise the heating resistor 40 to the target temperature is reduced. The energy efficiency of the thermal print head 1 when printing on the print medium can be improved.

[0055] In the thermal print head 1 of the present embodiment, the first electrode is the individual electrode 30 , and the second electrode is the common electrode 20 .

[0056] Therefore, the thermal resistance of the second strip-shaped portion 34 is further increased, and the heat dissipation from the heating resistor 40 to the base 31 of the individual electrode 30 through the second strip-shaped portion 34 is further reduced. The energy required to raise the heating resistor 40 to the target temperature is reduced. The energy efficiency of the thermal print head 1 when printing on the print medium can be improved.

[0057] In the thermal print head 1 of the present embodiment, the first electrode is the common electrode 20 , and the second electrode is the individual electrode 30 .

[0058] Therefore, the thermal resistance of the second strip-shaped portion 24 is further increased, and the heat dissipation from the heating resistor 40 to the base portion 21 of the common electrode 20 through the second strip-shaped portion 24 is further reduced. The energy required to raise the heating resistor 40 to the target temperature is reduced. The energy efficiency of the thermal print head 1 when printing on the print medium can be improved.

[0059] (Implementation Method 2)

[0060] Reference Figures 8 to 10 Next, the thermal print head 1 of the second embodiment will be described. The thermal print head 1 of this embodiment has a similar configuration to the thermal print head 1 of the first embodiment, and is different from the thermal print head 1 of the first embodiment mainly in the following aspects.

[0061] The outer width W of the second strip-shaped portion 24 of this embodiment is 13 The outer width W of the second strip-shaped portion 24 in the first embodiment is greater than that of the second strip-shaped portion 24 in the first embodiment. 13 Greater than the width W of the first strip-shaped portion 23 11 , and is smaller than the width W of the base 21 at the connection between the second strip-shaped portion 24 and the base 21 1b .

[0062] An insulating region 26 is provided inside the second strip-shaped portion 24. The insulating region 26 is a region where the common electrode 20 is not formed. The insulating region 26 is formed by Figure 4 The wiring layer 15 is formed by removing a portion of the metal layer in the step ( S2 ) of forming the wiring layer 15 . The insulating region 26 may extend to the connection portion between the second strip-shaped portion 24 and the base portion 21 .

[0063] The width of a portion of the second strip-shaped portion 24 (eg, W 12 ) is smaller than the width W of the base 21 at the connection between the second strip-shaped portion 24 and the base 21 1b , and is equal to or smaller than the width W of the first strip-shaped portion 23 11 The width of a portion of the second strip-shaped portion 24 (eg, W 12 ) is determined by the width w 11 With width w12 The sum of the width w is given by 11 The width w is the width of the portion of the second strip-shaped portion 24 located on one side in the arrangement direction (X direction) of the plurality of extension portions 22 relative to the insulating region 26. 12 It is the width of the portion of the second strip-shaped portion 24 located on the other side in the arrangement direction (X direction) of the plurality of extending portions 22 with respect to the insulating region 26 .

[0064] The outer width W of the second strip-shaped portion 34 of this embodiment is 23 The outer width W of the second strip-shaped portion 34 in the first embodiment is greater than that of the second strip-shaped portion 34 in the first embodiment. 23 Greater than the width W of the first strip-shaped portion 33 21 , and the width W of the base 31 at the connection between the second strip-shaped portion 34 and the base 31 2b equal.

[0065] An insulating region 36 is provided inside the second strip-shaped portion 34. The insulating region 36 is a region where the individual electrodes 30 are not formed. Figure 4 The wiring layer 15 is formed by removing a portion of the metal layer in the step ( S2 ) of forming the wiring layer 15 . The insulating region 36 may extend to the connection portion between the second strip-shaped portion 34 and the base portion 31 .

[0066] The width of a portion of the second strip-shaped portion 34 (eg, W 22 ) is smaller than the width W of the base 31 at the connection between the second strip-shaped portion 24 and the base 21 2b , and is equal to or smaller than the width W of the first strip-shaped portion 33 21 The width of a portion of the second strip-shaped portion 34 (eg, W 22 ) is determined by the width w 21 With width w 22 The sum of the width w is given by 21 The width w is the width of the portion of the second strip-shaped portion 34 located on one side in the arrangement direction (X direction) of the plurality of extension portions 32 relative to the insulating region 36. 22 It is the width of the portion of the second strip-shaped portion 34 located on the other side in the arrangement direction (X direction) of the plurality of extending portions 32 with respect to the insulating region 36 .

[0067] The thermal print head 1 of the present embodiment achieves the following effects similar to those of the thermal print head 1 of the first embodiment.

[0068] In the thermal print head 1 of the present embodiment, an insulating region (insulating region 26 or insulating region 36 ) is provided inside at least a portion of the second belt-shaped portion (second belt-shaped portion 24 or second belt-shaped portion 34 ).

[0069] Therefore, the thermal resistance of the second strip-shaped portion (the second strip-shaped portion 24 or the second strip-shaped portion 34) increases, and the heat dissipation from the heating resistor 40 through the second strip-shaped portion toward the base (base 21 or base 31) of the first electrode (common electrode 20 or individual electrode 30) is reduced. The energy required to raise the heating resistor 40 to the target temperature is reduced. The energy efficiency of the thermal print head 1 when printing on the printing medium can be improved.

[0070] Hereinafter, various aspects of the present disclosure are collectively described in the form of supplementary notes.

[0071] (Note 1)

[0072] A thermal print head having:

[0073] A heating resistor, including a heating portion;

[0074] A first electrode connected to the heating resistor; and

[0075] A second electrode connected to the heating resistor;

[0076] The heat generating portion is a portion of the heat generating resistor sandwiched between the first electrode and the second electrode.

[0077] The first electrode includes a base portion and an extension portion extending from the base portion toward the heating resistor, the extension portion includes a first strip portion and a second strip portion connected to the first strip portion and the base portion.

[0078] The first strip-shaped portion contacts the heating resistor and overlaps the second electrode in the longitudinal direction of the heating resistor.

[0079] The second strip-shaped portion does not overlap with the second electrode in the longitudinal direction of the heating resistor.

[0080] The first width of the first strip-shaped portion is smaller than the second width of the base portion at a connection portion between the second strip-shaped portion and the base portion.

[0081] The third width of the second strip-shaped portion at the connecting portion is smaller than the second width,

[0082] The width of at least a portion of the second strip-shaped portion is less than the first width,

[0083] The length of the second strip-shaped portion is greater than half of a difference between the length of the first strip-shaped portion and a width of the heating resistor.

[0084] (Note 2)

[0085] A thermal print head having:

[0086] A heating resistor, including a heating portion;

[0087] A first electrode connected to the heating resistor; and

[0088] A second electrode connected to the heating resistor;

[0089] The heat generating portion is a portion of the heat generating resistor sandwiched between the first electrode and the second electrode.

[0090] The first electrode includes a base portion and an extension portion extending from the base portion toward the heating resistor, the extension portion includes a first strip portion and a second strip portion connected to the first strip portion and the base portion.

[0091] The first strip-shaped portion contacts the heating resistor and overlaps the second electrode in the longitudinal direction of the heating resistor.

[0092] The second strip-shaped portion does not overlap with the second electrode in the longitudinal direction of the heating resistor.

[0093] The first width of the first strip-shaped portion is smaller than the second width of the base portion at a connection portion between the second strip-shaped portion and the base portion.

[0094] The third width of the second strip-shaped portion at the connecting portion is smaller than the second width,

[0095] A width of at least a portion of the second strip-shaped portion is smaller than the first width.

[0096] (Note 3)

[0097] The thermal print head according to Supplementary Note 1, wherein an insulating region is provided inside the at least a portion of the second belt-shaped portion.

[0098] (Note 4)

[0099] The thermal print head according to Supplementary Note 2, wherein an insulating region is provided inside the at least a portion of the second belt-shaped portion.

[0100] (Note 5)

[0101] The thermal print head according to Supplementary Note 1 or Supplementary Note 3, wherein the thickness of the second belt-shaped portion is smaller than the thickness of the base portion.

[0102] (Note 6)

[0103] The thermal print head according to Supplementary Note 2 or Supplementary Note 4, wherein the thickness of the second belt-shaped portion is smaller than the thickness of the base portion.

[0104] (Note 7)

[0105] The thermal print head according to any one of Supplementary Notes 1 to 6, wherein the first electrode is a single electrode,

[0106] The second electrode is a common electrode.

[0107] (Note 8)

[0108] The thermal print head according to any one of Supplementary Notes 1 to 6, wherein the first electrode is a common electrode,

[0109] The second electrode is a single electrode.

[0110] The first and second embodiments disclosed this time are to be considered as illustrative in all aspects and not restrictive. The scope of the present disclosure is indicated by the claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0111] [Explanation of symbols]

[0112] 1: Thermal print head

[0113] 10:Substrate

[0114] 11: Main side

[0115] 12: Glaze layer

[0116] 15: Wiring layer

[0117] 20: Common electrode

[0118] 21,31: base

[0119] 22,32: Extension

[0120] 23,33: 1st band

[0121] 24,34: Second band

[0122] 26,36: Insulation area

[0123] 30: Single electrode

[0124] 35: Solder pad

[0125] 40: Heating resistor

[0126] 41: Heating part

[0127] 45: Protective layer.

Claims

1. A thermal print head having: 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 heat generating portion is a portion of the heat generating resistor sandwiched between the first electrode and the second electrode. The first electrode includes a base portion and an extension portion extending from the base portion toward the heating resistor, the extension portion includes a first strip portion and a second strip portion connected to the first strip portion and the base portion. The first strip-shaped portion contacts the heating resistor and overlaps the second electrode in the longitudinal direction of the heating resistor. The second strip-shaped portion does not overlap with the second electrode in the longitudinal direction of the heating resistor. The first width of the first strip-shaped portion is smaller than the second width of the base portion at a connection portion between the second strip-shaped portion and the base portion. The third width of the second strip-shaped portion at the connecting portion is smaller than the second width, The width of at least a portion of the second strip-shaped portion is less than the first width, The length of the second strip-shaped portion is greater than half of a difference between the length of the first strip-shaped portion and a width of the heating resistor. 2 . The thermal print head according to claim 1 , wherein an insulating region is provided inside the at least a portion of the second band-shaped portion. 3 . The thermal print head according to claim 1 , wherein a thickness of the second belt-shaped portion is smaller than a thickness of the base portion. 4 . The thermal print head according to claim 1 , wherein the first electrode is an individual electrode, and the second electrode is a common electrode. 5 . The thermal print head according to claim 1 , wherein the first electrode is a common electrode, and the second electrode is an individual electrode.

6. A thermal print head having: 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 heat generating portion is a portion of the heat generating resistor sandwiched between the first electrode and the second electrode. The first electrode includes a base portion and an extension portion extending from the base portion toward the heating resistor, the extension portion includes a first strip portion and a second strip portion connected to the first strip portion and the base portion. The first strip-shaped portion contacts the heating resistor and overlaps the second electrode in the longitudinal direction of the heating resistor. The second strip-shaped portion does not overlap with the second electrode in the longitudinal direction of the heating resistor. The first width of the first strip-shaped portion is smaller than the second width of the base portion at a connection portion between the second strip-shaped portion and the base portion. The third width of the second strip-shaped portion at the connecting portion is smaller than the second width, A width of at least a portion of the second strip-shaped portion is smaller than the first width. 7 . The thermal print head according to claim 6 , wherein an insulating region is provided inside the at least a portion of the second belt-shaped portion. 8 . The thermal print head according to claim 6 , wherein a thickness of the second belt-shaped portion is smaller than a thickness of the base portion. 9 . The thermal print head according to claim 6 , wherein the first electrode is an individual electrode, and the second electrode is a common electrode. 10 . The thermal print head according to claim 6 , wherein the first electrode is a common electrode, and the second electrode is an individual electrode.

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