JP2022112463A - Thermal print head, thermal printer and thermal print head manufacturing method - Google Patents

Abstract

To provide a thermal print head which can suppress occurrence of a sticking phenomenon.SOLUTION: A thermal print head A1 comprises: a base material 10 having a principal plane 11 facing one side of a thickness direction z; a resistor layer 4 which is located on the principal plane 11, and includes a plurality of heating parts 41 arranged in a main scanning direction x; an electrode layer which is located on the principal plane 11, and constitutes a continuity route to the plurality of heating parts 41; and a protective layer 2 which covers the resistor layer 4 and the electrode layer. The protective layer 2 has a first area 21 which is overlapped with the plurality of heating parts 41 when viewed in the thickness direction z, and extends in the main scanning direction x when viewed in the thickness direction z. The first area 21 has a plurality of first recesses 22 and a plurality of first protrusions 23 which are alternately arranged along the main scanning direction x.SELECTED DRAWING: Figure 6

Description

The present disclosure relates to thermal printheads, thermal printers, and methods of manufacturing thermal printheads.

Patent Document 1 discloses an example of a conventional thermal printhead. The thermal printhead disclosed in the same document comprises a substrate, a glaze layer, a plurality of electrodes, a heating resistor and a protective layer. The glaze layer is made of glass, for example, and formed on the substrate. A plurality of electrodes are formed on the glaze layer. The plurality of electrodes are for energizing the heating resistor. A heating resistor is a heat source and is deposited on the glaze layer via a plurality of electrodes. A protective layer covers the plurality of electrodes and the heating resistor.

In such a thermal printhead, a print medium such as thermal paper is pressed against the heating resistors by a platen roller. Then, dots are printed on a printing medium such as thermal paper by heat from the heating resistor. The print medium is conveyed in the sub-scanning direction by the rotation of the platen roller.

JP 2011-240641 A

For example, when printing on thermal paper, a sticking phenomenon may occur in which the thermal paper unnecessarily sticks to the thermal print head. When the sticking phenomenon occurs, the thermal paper is not conveyed smoothly, resulting in deterioration of print quality.

The present disclosure has been made in view of the circumstances described above, and an object thereof is to provide a thermal print head capable of suppressing the occurrence of the sticking phenomenon.

A thermal printhead provided by the first aspect of the present disclosure includes a substrate having a main surface facing one of the thickness directions, and a plurality of substrates arranged on the main surface and arranged in the main scanning direction. a resistor layer including a heat generating portion; an electrode layer disposed on the main surface and forming a conduction path to the plurality of heat generating portions; and a protective layer covering the resistor layer and the electrode layer. wherein the protective layer has a first region that overlaps the plurality of heat generating portions when viewed in the thickness direction and extends in the main scanning direction when viewed in the thickness direction, and the first region is , a plurality of first concave portions and a plurality of first convex portions alternately arranged along the main scanning direction.

A thermal printer provided by the second aspect of the present disclosure comprises a thermal printhead provided by the first aspect and a platen facing the thermal printhead.

A method for manufacturing a thermal printhead provided by a third aspect of the present disclosure includes the steps of preparing a substrate having a major surface facing one of the thickness directions; a step of forming a resistor layer including a plurality of heat generating portions arranged in a direction; a step of forming an electrode layer arranged on the main surface and constituting a conductive path to the plurality of heat generating portions; and forming a protective layer covering the resistor layer and the electrode layer, wherein the protective layer overlaps the plurality of heat-generating portions when viewed in the thickness direction, and the thickness direction It has a first region extending in the main scanning direction, and the first region has a plurality of first concave portions and a plurality of first convex portions alternately arranged along the main scanning direction.

According to the thermal printhead of the present disclosure, it is possible to suppress the occurrence of the sticking phenomenon. Also, according to the thermal printer of the present disclosure, the occurrence of the sticking phenomenon is suppressed. Furthermore, according to the thermal printhead manufacturing method of the present disclosure, it is possible to manufacture a thermal printhead in which the sticking phenomenon is suppressed.

FIG. 1 is a plan view showing the thermal print head according to the first embodiment. FIG. FIG. 2 is a cross-sectional view along line II-II of FIG. FIG. 3 is a plan view of a part of FIG. 1 enlarged. FIG. 4 is a plan view of the essential part of FIG. 3 with the protective layer omitted. FIG. 5 is a cross-sectional view of a main part taken along line VV of FIG. FIG. 6 is a cross-sectional view of the essential part along line VI-VI of FIG. FIG. 7 is a flow chart showing an example of a method for manufacturing a thermal print head according to the first embodiment. FIG. 8 is a plan view showing one step of the method for manufacturing the thermal print head according to the first embodiment. FIG. 9 is a plan view showing one step of the method of manufacturing the thermal print head according to the first embodiment. FIG. 10 is a plan view showing one step of the method for manufacturing the thermal print head according to the first embodiment; FIG. 11 is a plan view showing one step of the method for manufacturing the thermal print head according to the first embodiment; FIG. 12 is a plan view of essential parts showing one step of the method of manufacturing the thermal print head according to the first embodiment. FIG. 13 is a cross-sectional view of essential parts showing one step of the method of manufacturing the thermal print head according to the first embodiment. FIG. 14 is a plan view of essential parts showing one step of the method of manufacturing the thermal print head according to the first embodiment. FIG. 15 is a cross-sectional view of essential parts showing one step of the method of manufacturing the thermal print head according to the first embodiment. FIG. 16 is a plan view of a main part showing one step of the method of manufacturing the thermal print head according to the first embodiment; FIG. 17 is a cross-sectional view of essential parts showing one step of the method of manufacturing the thermal print head according to the first embodiment. FIG. 18 is a plan view of a main part showing one step of the method of manufacturing the thermal print head according to the first embodiment; FIG. 19 is a fragmentary cross-sectional view showing a thermal print head according to a modification of the first embodiment; FIG. 20 is a plan view of essential parts showing a thermal print head according to the second embodiment. FIG. 21 is a plan view of essential parts in FIG. 20 with the protective layer omitted. 22 is a cross-sectional view taken along line XXII-XXII of FIG. 21. FIG. 23 is a cross-sectional view taken along line XXIII-XXIII of FIG. 21. FIG. FIG. 24 is a flow chart showing an example of a method for manufacturing a thermal print head according to the second embodiment. FIG. 25 is a cross-sectional view of essential parts showing one step of a method of manufacturing a thermal print head according to the second embodiment. FIG. 26 is a plan view of essential parts showing one step of a method of manufacturing a thermal print head according to the second embodiment. FIG. 27 is a plan view of a main part showing one step of a method of manufacturing a thermal print head according to the second embodiment; FIG. 28 is a plan view of a main part showing one step of a method of manufacturing a thermal print head according to the second embodiment; FIG. 29 is a cross-sectional view of essential parts showing a step of a method of manufacturing a thermal print head according to the second embodiment. FIG. 30 is a plan view of essential parts showing one step of a method of manufacturing a thermal print head according to the second embodiment. FIG. 31 is a plan view of essential parts showing one step of a method of manufacturing a thermal print head according to the second embodiment. FIG. 32 is a cross-sectional view of essential parts showing a step of a method of manufacturing a thermal print head according to the second embodiment. FIG. 33 is a plan view of a main part showing one step of a method of manufacturing a thermal print head according to the second embodiment; FIG. 34 is a fragmentary plan view showing a thermal print head according to a modified example (first modified example) of the second embodiment. FIG. 35 is a fragmentary cross-sectional view showing a thermal print head according to another modification (second modification) of the second embodiment. FIG. 36 is a flow chart showing an example of a method for manufacturing a thermal print head according to another modification (second modification) of the second embodiment. FIG. 37 is a fragmentary cross-sectional view showing a thermal print head according to another modification (third modification) of the second embodiment. FIG. 38 is a flow chart showing an example of a method for manufacturing a thermal print head according to another modification (third modification) of the second embodiment. FIG. 39 is a plan view showing a thermal print head according to the third embodiment; FIG. 40 is a plan view of the main part of FIG. 39 with a part enlarged; 41 is a cross-sectional view along line XLI-XLI in FIG. 40. FIG. 42 is a cross-sectional view along line XLII-XLII in FIG. 40. FIG. FIG. 43 is a flow chart showing an example of a method of manufacturing a thermal print head according to the third embodiment. FIG. 44 is a cross-sectional view of a main part showing one step of a method of manufacturing a thermal print head according to the third embodiment; FIG. 45 is a cross-sectional view of a main part showing one step of a method of manufacturing a thermal print head according to the third embodiment; FIG. 46 is a fragmentary cross-sectional view showing one step of a method of manufacturing a thermal print head according to the third embodiment. FIG. 47 is a fragmentary cross-sectional view showing one step of a method for manufacturing a thermal print head according to the third embodiment; FIG. 48 is a fragmentary cross-sectional view showing one step of a method of manufacturing a thermal print head according to the third embodiment. FIG. 49 is a fragmentary cross-sectional view showing one step of a method of manufacturing a thermal print head according to the third embodiment. FIG. 50 is a fragmentary cross-sectional view showing one step of a method of manufacturing a thermal print head according to the third embodiment. FIG. 51 is a fragmentary cross-sectional view showing one step of a method of manufacturing a thermal print head according to the third embodiment. FIG. 52 is a fragmentary cross-sectional view showing one step of a method for manufacturing a thermal print head according to the third embodiment. FIG. 53 is a fragmentary cross-sectional view showing one step of a method of manufacturing a thermal print head according to the third embodiment. FIG. 54 is a cross-sectional view of a main part showing one step of a method of manufacturing a thermal print head according to the third embodiment; FIG. 55 is a fragmentary cross-sectional view showing one step of a method of manufacturing a thermal print head according to the third embodiment. FIG. 56 is a plan view of essential parts showing a thermal print head according to a fourth embodiment. FIG. 57 is a cross-sectional view of essential parts along the LVII--LVII line in FIG. FIG. 58 is a cross-sectional view of essential parts taken along line LVIII--LVIII in FIG. FIG. 59 is a flow chart showing a method of manufacturing a thermal print head according to the fourth embodiment. FIG. 60 is a cross-sectional view of essential parts showing a step of a method of manufacturing a thermal print head according to the fourth embodiment. FIG. 61 is a cross-sectional view of essential parts showing a step of a method of manufacturing a thermal print head according to the fourth embodiment. FIG. 62 is a fragmentary cross-sectional view showing one step of a method of manufacturing a thermal print head according to the fourth embodiment. FIG. 63 is a fragmentary cross-sectional view showing one step of a method for manufacturing a thermal print head according to the fourth embodiment. FIG. 64 is a fragmentary cross-sectional view showing one step of a method for manufacturing a thermal print head according to the fourth embodiment. FIG. 65 is a fragmentary cross-sectional view showing one step of a method for manufacturing a thermal print head according to the fourth embodiment. FIG. 66 is a fragmentary cross-sectional view showing one step of a method for manufacturing a thermal print head according to the fourth embodiment. FIG. 67 is a cross-sectional view of a main part showing one step of a method of manufacturing a thermal print head according to the fourth embodiment; FIG. 68 is a plan view of essential parts showing a thermal print head according to a fifth embodiment. FIG. 69 is a cross-sectional view of the essential part along line LXIX-LXIX in FIG. FIG. 70 is a flow chart showing a method of manufacturing a thermal print head according to the fifth embodiment. FIG. 71 is a fragmentary cross-sectional view showing one step of a method of manufacturing a thermal print head according to the fifth embodiment. FIG. 72 is a fragmentary cross-sectional view showing a step of a method of manufacturing a thermal print head according to the fifth embodiment; FIG. 73 is a fragmentary cross-sectional view showing a thermal print head according to a modified example (first modified example) of the fifth embodiment. FIG. 74 is a flow chart showing a method of manufacturing a thermal print head according to a modified example (first modified example) of the fifth embodiment. FIG. 75 is a plan view of a main part showing a thermal print head showing another configuration according to a modified example (first modified example) of the fifth embodiment. FIG. 76 is a fragmentary plan view showing a thermal print head according to another modification (second modification) of the fifth embodiment. FIG. 77 is a fragmentary plan view showing a thermal print head according to another modification (second modification) of the fifth embodiment. FIG. 78 is a cross-sectional view of the main part taken along line LXXVIII--LXXVIII in FIG. FIG. 79 is a flow chart showing a method of manufacturing a thermal print head according to another modification (second modification) of the fifth embodiment.

Preferred embodiments of the thermal printhead of the present disclosure will be described below with reference to the drawings. Below, the same or similar components are denoted by the same reference numerals, and overlapping descriptions are omitted.

In the present disclosure, "a certain entity A is formed on a certain entity B" and "a certain entity A is formed on (of) an entity B" mean "a certain entity A is directly formed in a certain thing B", and "a certain thing A is formed in a certain thing B while another thing is interposed between a certain thing A and a certain thing B" including. Similarly, ``an entity A is arranged on an entity B'' and ``an entity A is arranged on (of) an entity B'' mean ``an entity A being placed directly on a certain thing B", and "a thing A being placed on a certain thing B with another thing interposed between something A and something B" include. Similarly, unless otherwise specified, ``an object A is located on (of) an object B'' means ``a certain object A is in contact with an object B, and an object A is located on an object B. It includes "located above" and "a certain entity A is located on a certain entity B while another entity is interposed between the entity A and the entity B." Similarly, unless otherwise specified, ``an entity A is laminated on an entity B'' and ``an entity A is laminated on (of) an entity B'' means ``an entity A "It is directly laminated on a certain thing B", and "A certain thing A is laminated on a certain thing B while another thing is interposed between a certain thing A and a certain thing B". include. In addition, unless otherwise specified, ``an object A overlaps an object B when viewed in a certain direction'' means ``an object A overlaps all of an object B'' and ``an object A overlaps an object B.'' It includes "overlapping a part of a certain thing B".

[First Embodiment]
1 to 6 show a thermal print head A1 according to the first embodiment. The thermal printhead A1 includes a head substrate 1, a protective layer 2, an electrode layer 3, a resistor layer 4, a connection substrate 5, a plurality of wires 61 and 62, a plurality of driver ICs 7, a protective resin 78 and a heat dissipation member 8. .

The thermal print head A1 is incorporated in a thermal printer Pr (see FIG. 2) that prints on the print medium P1. The thermal printer Pr has a thermal print head A1 and a platen roller G1. A platen roller G1 faces the thermal print head A1. The print medium P1 is sandwiched between the thermal print head A1 and the platen roller G1 and conveyed in the sub-scanning direction by the platen roller G1. Such a print medium P1 includes, for example, a barcode sheet and thermal paper for creating a receipt. The thermal print head A1 has a plurality of heat-generating portions 41 formed in the resistor layer 4 according to a configuration which will be described in detail later. conduct. A flat rubber platen may be used instead of the platen roller G1. The platen includes an arcuate portion of cylindrical rubber having a large radius of curvature when viewed in cross section. In this disclosure, the term "platen" includes both platen roller G1 and flat platens. The thermal printer Pr is not limited to one that prints directly on thermal paper, and may be of a thermal transfer type that selectively applies heat to an ink ribbon to print on a print medium.

FIG. 1 is a plan view showing the thermal print head A1. In FIG. 1, a first region 21, which will be described later, of the protective layer 2 is indicated by an imaginary line (a chain double-dashed line), and other portions of the protective layer 2 are omitted. FIG. 2 is a cross-sectional view along line II-II of FIG. FIG. 3 is a plan view of a part of FIG. 1 enlarged. FIG. 4 is a plan view of the essential part of FIG. 3 with the protective layer 2 omitted. In FIG. 4, a first region 21, which will be described later, is indicated by imaginary lines. FIG. 5 is a cross-sectional view of a main part taken along line VV of FIG. FIG. 6 is a cross-sectional view of the essential part along line VI-VI of FIG. In these figures, the thickness direction of the head substrate 1 is z, the main scanning direction is x, and the sub-scanning direction is y. The thickness direction z, the main scanning direction x and the sub-scanning direction y are orthogonal to each other. During printing, the print medium P1 is fed in the direction indicated by the arrow in the sub-scanning direction y (see FIG. 2). In the sub-scanning direction y, the direction indicated by the arrow in the drawing is downstream, and the opposite direction is upstream. In addition, in the thickness direction z, the direction indicated by the arrow in the drawing is the upward direction, and the opposite direction is the downward direction.

The head substrate 1 has a plate shape elongated in the main scanning direction x as shown in FIG. The head substrate 1 is a supporting member for the protective layer 2 , the electrode layer 3 , the resistor layer 4 and the plurality of driver ICs 7 . The head substrate 1 has a base material 10 and a glaze layer 14 .

Base material 10 is made of ceramic such as AlN (aluminum nitride), Al ₂ O ₃ (alumina), and zirconia. Base material 10 has a thickness of, for example, 0.6 mm or more and 1.0 mm or less. As shown in FIG. 1, the base material 10 has a rectangular shape elongated in the main scanning direction x when viewed in the thickness direction z. Base material 10 has main surface 11 and back surface 12, as shown in FIGS. The main surface 11 and the back surface 12 are spaced apart in the thickness direction z. The main surface 11 is the upper surface of the base material 10 and faces upward in the thickness direction z. The back surface 12 is the lower surface of the base material 10 and faces downward in the thickness direction z.

Glaze layer 14 is formed on substrate 10 as shown in FIGS. Glaze layer 14 covers at least part of main surface 11 . The glaze layer 14 is made of a glass material such as amorphous glass. Glaze layer 14 includes partial glaze 15 and full glaze 16 . The glaze layer 14 may be composed of only the partial glaze 15 without including the full glaze 16 .

Partial glaze 15 is formed on main surface 11 . The partial glaze 15 bulges in the thickness direction z when viewed in the main scanning direction x. Partial glaze 15 includes a plurality of separating portions 151 .

The plurality of separating portions 151 are separated from each other. As shown in FIG. 5, each separating portion 151 has a cross section along a plane (yz plane) perpendicular to the main scanning direction x and has an arcuate edge. Each separating portion 151 has a strip shape extending in the sub-scanning direction y when viewed in the thickness direction z. The plurality of separating portions 151 are arranged along the main scanning direction x and arranged parallel to each other.

The full glaze 16 covers the partial glaze 15 and covers the main surface 11 exposed from the partial glaze 15, as shown in FIGS. The full-surface glaze 16 is provided to form a smooth surface suitable for forming the electrode layer 3 by covering the main surface 11, which is a relatively rough surface. In the example shown in FIGS. 4 and 5 , the full glaze 16 covers the partial glaze 15 , but it may not cover the partial glaze 15 but may cover only the main surface 11 exposed from the partial glaze 15 . The thickness of the full-surface glaze 16 is, for example, about 2.0 μm.

In the glaze layer 14, the partial glaze 15 is made of a glass material having a softening point of, for example, 800.degree. C. to 850.degree. That is, the glass material forming the full glaze 16 has a lower softening point than the glass material forming the partial glaze 15 . Further, it is preferable that the material of the full glaze 16 is a glass paste having a lower viscosity than the glass paste that is the material of the partial glaze 15 .

The electrode layer 3 constitutes a conduction path for energizing the resistor layer 4 . The electrode layer 3 is made of a conductive material. The conductive material is, for example, a metal such as Au (gold), Ag (silver), Cu (copper), or an alloy containing any of these. The electrode layer 3 is formed on the glaze layer 14 of the substrate 10 . A thickness t1 (see FIG. 6) of electrode layer 3 is, for example, about 0.6 μm. The thickness t1 is a dimension along the thickness direction z. The electrode layer 3 has a common electrode 31 and a plurality of individual electrodes 32 . The shape and arrangement of each part of the electrode layer 3 are not limited to the example shown in FIG. 4, and various configurations are possible. Also, the material of each part of the electrode layer 3 is not limited.

The common electrode 31 includes a plurality of belt-like portions 311 and connecting portions 312, as shown in FIG. The connecting portion 312 is arranged near the edge of the head substrate 1 on the downstream side in the sub-scanning direction y, and has a strip shape extending in the main scanning direction x. The plurality of band-shaped portions 311 each extend from the connecting portion 312 in the sub-scanning direction y, and are arranged at equal pitches along the main scanning direction x. The arrangement pitch of the plurality of strip portions 311 in the main scanning direction x is, for example, 42.3 μm or more and 84.6 μm or less. The tip of each band-shaped portion 311 (the upstream end in the sub-scanning direction y) is positioned on each separating portion 151 . Each band-shaped portion 311 overlaps the resistor layer 4 when viewed in the thickness direction z.

In the example shown in FIGS. 4 and 5, the Ag layer 312a is laminated on the connecting portion 312, but the Ag layer 312a may not be formed. The Ag layer 312a reduces the resistance value of the connecting portion 312. As shown in FIG. The Ag layer 312a is formed, for example, by printing and firing a paste containing an organic Ag compound or a paste containing Ag particles, glass frit, palladium and resin.

The plurality of individual electrodes 32 are for partially energizing the resistor layer 4 . Each individual electrode 32 has a reverse polarity with respect to the common electrode 31 . Each individual electrode 32 extends from the resistor layer 4 toward the driver IC 7 . A plurality of individual electrodes 32 are arranged along the main scanning direction x. Each of the plurality of individual electrodes 32 includes a strip-shaped portion 321 , a bonding portion 322 and a connecting portion 323 .

As shown in FIG. 4, the belt-like portion 321 extends in the sub-scanning direction y and has a belt-like shape when viewed in the thickness direction z. Each strip-shaped portion 321 is arranged between two adjacent strip-shaped portions 321 of the common electrode 31 . The arrangement pitch of the plurality of strip portions 321 in the main scanning direction x is, for example, 42.3 μm or more and 84.6 μm or less. The tip of each band-shaped portion 321 (the downstream end in the sub-scanning direction y) is positioned on each separating portion 151 . Each strip 321 overlaps the resistor layer 4 when viewed in the thickness direction z. Each band-shaped portion 321 has a portion that overlaps with each band-shaped portion 311 when viewed in the main scanning direction x. This portion is located on each separation 151 .

The bonding portion 322 is formed at the end portion of each individual electrode 32 on the upstream side in the sub-scanning direction y, as shown in FIG. Each wire 61 is bonded to each bonding portion 322 . Thereby, each individual electrode 32 and the driver IC 7 are electrically connected via each wire 61 . The bonding portion 322 is exposed from the protective layer 2, as shown in FIG.

The connecting portion 323 connects the strip portion 321 and the bonding portion 322 as shown in FIG. The connecting portion 323 extends from the strip portion 321 toward the upstream side in the sub-scanning direction y. The connecting portion 323 includes a parallel portion 323a and an oblique portion 323b, as shown in FIG. The parallel portion 323a has one end connected to the bonding portion 322 and extends along the sub-scanning direction y. The oblique portion 323b is inclined with respect to the sub-scanning direction y. The oblique portion 323b is sandwiched between the parallel portion 323a and the strip portion 321 in the sub-scanning direction y.

The resistor layer 4 is made of a material having a higher resistivity than the material forming the electrode layer 3 . Resistor layer 4 is made of, for example, ruthenium oxide. The resistor layer 4 is formed on the partial glaze 15 as shown in FIG. As shown in FIGS. 1, 3 and 4, the resistor layer 4 has a strip shape extending in the main scanning direction x when viewed in the thickness direction z. The resistor layer 4 intersects each strip-shaped portion 311 (common electrode 31) and each strip-shaped portion 321 (each individual electrode 32) when viewed in the thickness direction z. In addition, the resistor layer 4 is formed across a plurality of isolation portions 151 when viewed in the thickness direction z. The resistor layer 4 is laminated on the side opposite to the substrate 10 with respect to the strip portions 311 and 321 in the thickness direction z. The thickness of resistor layer 4 is, for example, 3 μm or more and 6 μm or less. Therefore, the thickness of the resistor layer 4 is greater than the thickness t<b>1 of the electrode layer 3 . The material and thickness of the resistor layer 4 are not limited.

The resistor layer 4 has a plurality of heat generating portions 41 . Each heat-generating portion 41 is a portion of the resistor layer 4 sandwiched between each strip-shaped portion 311 and each strip-shaped portion 321 . Each heat generating portion 41 generates heat by being partially energized by the electrode layer 3 . A print dot is formed by the heat generated by each heat generating portion 41 . A plurality of heat generating portions 41 are arranged along the main scanning direction x. The dot density of the thermal print head A1 increases as the number of heat generating portions 41 arranged in the main scanning direction x per unit length (for example, 1 mm) of the substrate 10 in the main scanning direction x increases. In this embodiment, each heat generating portion 41 overlaps between two separation portions 151 adjacent to each other in the main scanning direction x when viewed in the thickness direction z.

The protective layer 2 is for protecting the electrode layer 3, the resistor layer 4, and the like. However, the protective layer 2 exposes each bonding portion 322 of the plurality of individual electrodes 32 . Protective layer 2 is made of, for example, amorphous glass. The protective layer 2 may have a structure in which a lower layer made of amorphous glass and an upper layer made of SiAlON or SiC (silicon carbide) are laminated instead of the structure made of amorphous glass. SiAlON is a silicon nitride-based engineering ceramic in which alumina (Al ₂ O ₃ ) and silica (SiO ₂ ) are synthesized with silicon nitride (Si ₃ N ₄ ). The upper layer is formed by sputtering, for example.

Protective layer 2 has a first region 21 . As shown in FIG. 1, the first region 21 is a strip-shaped region extending along the main scanning direction x when viewed in the thickness direction z. The first region 21 overlaps the plurality of heat generating portions 41 (resistor layer 4) when viewed in the thickness direction z. Heat from the plurality of heat generating portions 41 is transferred to the first region 21 . The first region 21 overlaps the plurality of separating portions 151 (partial glazes 15) when viewed in the thickness direction z. The first area 21 includes an area of the protective layer 2 against which the print medium P1 is pressed by the platen roller G1 when the print medium P1 is printed. In the example shown in FIG. 3 , both ends of the first region 21 in the sub-scanning direction y overlap the separating portions 151 when viewed in the thickness direction z. The first region 21 includes a plurality of first concave portions 22 and a plurality of first convex portions 23, as shown in FIG. 6 is a cross section in the first region 21. FIG.

The plurality of first concave portions 22 and the plurality of first convex portions 23 are alternately arranged along the main scanning direction x. A step d<b>1 along the thickness direction z between each first concave portion 22 and each first convex portion 23 is larger than the thickness t<b>1 of the electrode layer 3 . The step d1 is the distance from the top of each first protrusion 23 to the bottom of each first recess 22 along the thickness direction z.

Each of the plurality of first recesses 22 is positioned above each heat generating portion 41, as shown in FIG. As can be understood from FIG. 6, each first concave portion 22 overlaps each heat generating portion 41 when viewed in the thickness direction z. Each of the plurality of first concave portions 22 is positioned between two separating portions 151 adjacent to each other in the main scanning direction x when viewed in the thickness direction z. In the example shown in FIG. 6, each first concave portion 22 has a downwardly curved shape in a cross section along a plane (xz plane) orthogonal to the sub-scanning direction y, but may have a flat bottom.

Each of the plurality of first convex portions 23 overlaps with each separation portion 151 when viewed in the thickness direction z. In the example shown in FIG. 6, each first projection 23 is flat in cross section along the xz plane, but may be curved upward. In the example shown in FIG. 5, each first convex portion 23 curves upward along each separation portion 151 in the cross section along the yz plane. As can be understood from FIG. 6 , the plurality of first convex portions 23 respectively overlap each band-shaped portion 311 or each band-shaped portion 321 when viewed in the thickness direction z.

In the first region 21 of the first region 21, the portions of the first region 21 that overlap the separation portions 151 swell upward to form the first protrusions 23, and the portions that do not overlap the separation portions 151 become the respective first convex portions 23. It becomes the first concave portion 22 .

The connection board 5 is arranged on the upstream side in the sub-scanning direction y with respect to the head board 1, as shown in FIGS. The connection board 5 is, for example, a printed board, and has a wiring pattern (not shown) formed thereon. A connector 59 to be described later is mounted on the connection substrate 5 . The shape of the connection board 5 is not particularly limited, but in this embodiment, it has a rectangular shape with the main scanning direction x as the longitudinal direction. The connection board 5 has a main surface 51 and a back surface 52 . The main surface 51 and the back surface 52 are spaced apart in the thickness direction z. The main surface 51 is the upper surface of the connection board 5 and faces the same direction as the main surface 11 . The back surface 52 is the lower surface of the connection board 5 and faces in the same direction as the back surface 12 .

A plurality of driver ICs 7 are mounted, for example, on the head substrate 1 and are for individually energizing the plurality of heat generating portions 41 . Each driver IC 7 may be mounted across the head substrate 1 and the connection substrate 5 , or may be mounted on the connection substrate 5 . A plurality of driver ICs 7 are connected to a plurality of individual electrodes 32 (a plurality of bonding portions 322) by a plurality of wires 61, as understood from FIGS. Power supply control to the plurality of heat generating portions 41 by the plurality of driver ICs 7 follows command signals input from the outside of the thermal print head A1 via the connection board 5 . A plurality of driver ICs 7 are connected to a wiring pattern (not shown) of the connection board 5 by a plurality of wires 62, as shown in FIG. A plurality of driver ICs 7 are appropriately provided according to the number of the plurality of heat generating portions 41 .

As understood from FIGS. 1 and 2, the plurality of driver ICs 7, the plurality of wires 61 and the plurality of wires 62 are covered with protective resin 78. FIG. The protective resin 78 is made of, for example, an insulating resin and is black, for example. As shown in FIGS. 1 and 2, the protective resin 78 is formed across the head substrate 1 and the connection substrate 5 .

A connector 59 is used to connect the thermal print head A1 to the thermal printer Pr. The connector 59 is attached to the connection board 5 and connected to a wiring pattern (not shown) of the connection board 5 .

The heat dissipation member 8 supports the head substrate 1 and the connection substrate 5, as shown in FIG. The heat radiating member 8 is for radiating part of the heat generated by the plurality of heat generating portions 41 to the outside through the head substrate 1 . The heat radiating member 8 is a block-shaped member made of metal such as aluminum. The heat dissipation member 8 has a support surface 81 as shown in FIG. The support surface 81 faces upward in the thickness direction z. The back surface 12 of the base material 10 and the back surface 52 of the connection board 5 are joined to the support surface 81 .

Next, an example of a method for manufacturing the thermal print head A1 will be described below with reference to FIGS. 7 to 18. FIG.

FIG. 7 is a flow chart showing an example of a method for manufacturing the thermal print head A1. 8, 9 and 11 are plan views showing one step of the method of manufacturing the thermal print head A1. 12, 14, 16 and 18 are plan views of essential parts showing one step of the method of manufacturing the thermal print head A1, and correspond to the plan view of essential parts of FIG. 10, 13, 15 and 17 are cross-sectional views of essential parts showing one step of the method of manufacturing the thermal print head A1, and correspond to the cross-sectional view of essential parts in FIG.

As shown in FIG. 7, the method for manufacturing the thermal print head A1 includes a substrate preparation step S11, a glaze formation step S12, an electrode layer formation step S13, a resistor layer formation step S14, a protective layer formation step S15, and a singulation step. It has S161 and assembly step S162.

[Base material preparation step S11]
First, the base material 10 is prepared. The substrate 10 to be prepared is a plate material made of ceramic, and examples of the ceramic include AlN, Al ₂ O ₃ and zirconia. The base material 10 to be prepared has a size that allows, for example, a plurality of head substrates 1 to be manufactured. Base material 10 has main surface 11 and back surface 12 as described above.

[Glaze Forming Step S12]
Next, a glaze layer 14 is formed on the main surface 11 of the substrate 10 . As shown in FIG. 7, in the glaze forming step S12, a partial glaze forming process S121, a partial glaze dividing process S122, and a full glaze forming process S123 are sequentially performed.

In the partial glaze forming process S121, as shown in FIG. 8, a thick film of glass paste 150 is printed on the main surface 11 and dried. The formed glass paste 150 has a rectangular shape extending in the main scanning direction x, as shown in FIG.

In the partial glaze division process S122, the dried glass paste 150 is divided into a plurality of separation portions 151, as shown in FIGS. The division into the plurality of separation portions 151 is performed by etching using an etchant such as hydrofluoric acid. The division may be performed by laser processing instead of etching. After that, by firing the plurality of separation portions 151, the partial glaze 15 including the plurality of separation portions 151 is formed.

In the entire glaze forming process S123, as shown in FIG. 11, a thick film of glass paste is printed on substantially the entire surface of the main surface 11 and fired. Thereby, a full-surface glaze 16 is formed. That is, the head substrate 1 having the base material 10 and the glaze layer 14 is formed. The formed full-surface glaze 16 covers the main surface 11 exposed from the partial glaze 15 while covering the partial glaze 15 (the plurality of separation portions 151 ). Further, the portion of the full glaze 16 that covers the partial glaze 15 protrudes upward from the portion that covers the main surface 11 .

[Electrode layer forming step S13]
Next, an electrode layer 3 is formed on the glaze layer 14 . In the electrode layer forming step S13, a conductive paste coating process, a conductive paste baking process, and a conductive film patterning process are performed in order.

In the conductive paste application process, as shown in FIGS. 12 and 13, a conductive paste 30 is applied on the glaze layer 14 by thick film printing, for example. As the conductive paste 30, for example, a resinate Au paste material is used. The resinate Au paste material contains Au as a metal component, and rhodium, vanadium, bismuth, silicon, etc. are added as additive elements, for example. The metal component is not limited to Au, and may be Ag, Cu, or the like.

In the conductive paste firing process, the conductive paste 30 is fired to form a conductive film. This conductive film contains Au as a metal component, and is formed as a film covering the region where the conductive paste 30 shown in FIGS. 12 and 13 is applied.

In the conductive film patterning process, the conductive film is patterned. For this patterning, for example, a photosensitive resist film is formed on the conductive film, and the resist film is patterned by photolithography. Next, using this resist film as a mask, the conductive film is etched. Thereby, the electrode layer 3 shown in FIGS. 14 and 15 is obtained. The Ag layer 312a may be formed by, for example, printing a thick film of a paste containing Ag on the connecting portion 312 of the common electrode 31 after patterning the conductive film, and then firing the paste.

Unlike the present embodiment, a photosensitive paste may be used as the conductive paste 30 . In this case, a patterning process can be performed by subjecting the conductive paste 30 to a photosensitive process using photolithography or the like.

[Resistor layer forming step S14]
Next, a resistor layer 4 is formed. In the resistor layer forming step S14, a resistor paste application process and a resistor paste firing process are performed in order.

In the resistor paste application process, a resistor paste containing ruthenium oxide is applied onto the glaze layer 14 by thick film printing or the like. At this time, the resistor paste is applied in a band shape extending in the main scanning direction x, and is applied on the glaze layer 14 so as to cross the plurality of band portions 311 and the plurality of band portions 321 . Also, the resistor paste is applied so as to straddle the plurality of separation portions 151 when viewed in the thickness direction z.

In the resistor paste firing process, the resistor paste is fired. Thus, resistor layer 4 shown in FIGS. 16 and 17 is formed. As shown in FIG. 17 , in the formed resistor layer 4 , the portion formed on the isolation portion 151 rises above the portion not formed on the isolation portion 151 . That is, the resistor layer 4 has unevenness in the thickness direction z.

[Protective layer forming step S15]
Next, protective layer 2 is formed. In the protective layer forming step S15, for example, a glass paste constituting the protective layer 2 is thick-film-printed on the glaze layer 14, the electrode layer 3 and the resistor layer 4 exposed to the outside after the resistor layer forming step S14. . Then, the thick-film-printed glass paste is fired. Thereby, the protective layer 2 shown in FIG. 18 is formed. On the surface of the protective layer 2 thus formed, unevenness is formed along the unevenness in the thickness direction z of the resistor layer 4 . That is, the protective layer 2 is formed with the first region 21 having the plurality of first concave portions 22 and the plurality of first convex portions 23 . The plurality of first concave portions 22 and the plurality of first convex portions 23 are alternately arranged along the main scanning direction x.

[Singulation step S161]
Next, the substrate 10 is appropriately divided into each head substrate 1 . Note that if the substrate 10 corresponding to one head substrate 1 has been prepared in the substrate preparation step S11, the singulation step S161 may not be performed. For the singulation step S161, for example, laser cutting or dicing is selected according to the material of the base material 10. FIG.

[Assembly step S162]
Thereafter, attachment of the head substrate 1 and the connection substrate 5 to the heat dissipation member 8, mounting of the driver IC 7, bonding of the plurality of wires 61 and 62, formation of the protective resin 78, and the like are performed. Through the steps shown in FIG. 6, the thermal print head A1 shown in FIGS. 1 to 6 is manufactured.

The method for manufacturing the thermal print head A1 described above is an example, and can be changed as appropriate. For example, in the above-described glaze forming step S12, the partial glaze forming process S121, the partial glaze dividing process S122, and the overall glaze forming process S123 are performed in this order. Different from this order, the entire glaze formation process S123, the partial glaze formation process S121, and the partial glaze division process S122 may be performed in this order. In this case, the full glaze 16 covers the entire main surface 11 of the substrate 10 , and the partial glazes 15 (separating portions 151 ) are formed on the full glaze 16 .

The actions and effects of the thermal print head A1 are as follows.

In the thermal printhead A1, the protective layer 2 has a first region 21, and the first region 21 has a plurality of first concave portions 22 and a plurality of first convex portions 23. As shown in FIG. The plurality of first concave portions 22 and the plurality of first convex portions 23 are alternately arranged along the main scanning direction x. According to this configuration, the surface of the protective layer 2 in the first region 21 undulates along the main scanning direction x. Therefore, during printing, when the print medium P1 is pressed against the thermal print head A1 by the platen roller G1, the print medium P1 comes into contact with the plurality of first protrusions 23 and the plurality of first recesses 22. no contact. Therefore, a small gap can be locally generated between the print medium P1 and the protective layer 2, so that the print medium P1 can be prevented from sticking to the thermal print head A1. That is, the thermal print head A1 can suppress the occurrence of the sticking phenomenon.

In the thermal print head A1, the step d1 along the thickness direction z between each of the plurality of first concave portions 22 and each of the plurality of first convex portions 23 is greater than the thickness t1 of the electrode layer 3 along the thickness direction z. is also big. In a thermal print head different from the thermal print head A1 and having a configuration in which the partial glaze 15 is not divided into a plurality of separation portions 151, the portion where the resistor layer 4 is formed on the electrode layer 3 and the portion on the electrode layer 3 A step may occur between the portion that is not formed on the glaze layer 14 (the portion formed on the glaze layer 14). However, this step is about the thickness t1 of the electrode layer 3, and the irregularities on the surface of the protective layer 2 caused by this step may not be able to secure an appropriate gap for suppressing the sticking phenomenon. On the other hand, in the thermal print head A1, the step d1 is larger than the thickness t1 of the electrode layer 3. As shown in FIG. Therefore, the thermal print head A1 can appropriately secure a local gap between the print medium P1 and the protective layer 2 in order to suppress the sticking phenomenon.

The partial glaze 15 is divided into a plurality of separation portions 151 in the thermal printhead A1. According to this configuration, a step is generated depending on the presence or absence of each isolation portion 151, and unevenness in the thickness direction z is formed in the resistor layer 4 formed on each isolation portion 151 (partial glaze 15). Concavities and convexities (a plurality of first concave portions 22 and a plurality of first convex portions 23 ) are formed on the surface of the protective layer 2 along the concave and convex portions of the resistor layer 4 . That is, the step d1 between each first concave portion 22 and each first convex portion 23 in the first region 21 has a size corresponding to the thickness of the partial glaze 15 (each separating portion 151). Moreover, the thickness of the partial glaze 15 (each separating portion 151 ) is greater than the thickness t<b>1 of the electrode layer 3 . Therefore, the thermal print head A<b>1 can form a step d<b>1 larger than the thickness t<b>1 of the electrode layer 3 on the surface of the protective layer 2 in the first region 21 .

FIG. 19 shows a thermal print head A2 according to a modification of the first embodiment. FIG. 19 is a cross-sectional view of the main parts showing the thermal print head A2 and corresponds to the cross-sectional view of the main parts of FIG.

In the thermal print head A1, each band-shaped portion 311 and each band-shaped portion 321 are formed on each separating portion 151, respectively. On the other hand, in the thermal print head A2, as shown in FIG. 19, each band-shaped portion 311 and each band-shaped portion 321 are formed so as to pass between two separating portions 151 adjacent to each other in the main scanning direction x.

As shown in FIG. 19, in the thermal print head A2, each first convex portion 23 overlaps each heat generating portion 41 when viewed in the thickness direction z. In addition, each first convex portion 23 overlaps each separation portion 151 when viewed in the thickness direction z. Each first concave portion 22 overlaps between two heat generating portions 41 adjacent to each other in the main scanning direction x when viewed in the thickness direction z. Also, each first concave portion 22 overlaps with each band-shaped portion 311 or each band-shaped portion 321 .

The thermal print head A2 also has the same effect as the thermal print head A1.

[Second embodiment]
20 to 23 show a thermal printhead B1 according to the second embodiment. In the thermal print head A1, the partial glaze 15 is divided into a plurality of separation portions 151 to form a plurality of first concave portions 22 and a plurality of first convex portions 23. As shown in FIG. On the other hand, the thermal print head B1 does not divide the partial glaze 15 into a plurality of separating portions 151, and forms a plurality of first concave portions 22 and a plurality of first convex portions 23 by a configuration described in detail later.

FIG. 20 is a plan view of the main part showing the thermal print head B1, and corresponds to FIG. FIG. 21 is a plan view of the essential parts of FIG. 20 with the protective layer 2 omitted, and corresponds to FIG. 22 is a cross-sectional view taken along line XXII-XXII of FIG. 21. FIG. 23 is a cross-sectional view taken along line XXIII-XXIII of FIG. 21. FIG.

As described above, the partial glaze 15 is not divided into multiple separated portions 151 . As can be understood from FIGS. 20 and 21, the partial glaze 15 is belt-shaped with the main scanning direction x as its longitudinal direction when viewed in the thickness direction z. Partial glaze 15 is exposed from full glaze 16, as can be seen from FIG. The full glaze 16 differs from the thermal print head A1 in the formation range. Unlike this configuration, the full-surface glaze 16 may be configured to cover the entire upper surface of the partial glaze 15, similar to the thermal print head A1. Note that the glaze layer 14 may not have the partial glaze 15 and the main surface 11 of the substrate 10 may be entirely covered with the glaze 16 .

The electrode layer 3 has the same parts as the electrode layer 3 of the thermal print head A1, but the positional relationship between the strips 311 and 321 is different from the electrode layer 3 of the thermal print head A1. As shown in FIG. 21, each band-shaped portion 321 is spaced apart from each band-shaped portion 311 in the sub-scanning direction y. In addition, the belt-shaped portions 321 and the belt-shaped portions 311 facing each other in the sub-scanning direction y have substantially the same position in the main scanning direction x.

The resistor layer 4 is divided into heat generating portions 41 as shown in FIGS. 21 and 23 . Each of the plurality of heat-generating portions 41 overlaps each strip-shaped portion 311 and each strip-shaped portion 321 facing each other in the sub-scanning direction y. That is, the dimension of each heat generating portion 41 in the sub-scanning direction y is greater than the distance in the sub-scanning direction y between each band-shaped portion 311 and each band-shaped portion 321 . Each dimension in the sub-scanning direction y of the plurality of heat generating portions 41 is substantially the same.

The protective layer 2 has a first layer 201, a second layer 202 and a third layer 203, as shown in FIGS. The first layer 201 is, for example, an oxide film, and the oxide film is made of, for example, SiO ₂ . The second layer 202 is, for example, a protective film, and the protective film is made of SiC, for example. The third layer 203 is, for example, an oxide film, and the oxide film is made of, for example, _SiO2 . In the examples shown in FIGS. 22 and 23, the second layer 202 is thicker than the first layer 201 and the third layer 203 respectively.

As can be seen from FIGS. 20 and 23, protective layer 2 has first layer 201 and second layer 202 partially removed. As a result, the protective layer 2 has a portion in which the first layer 201, the second layer 202 and the third layer 203 are laminated in order, and a portion consisting of the third layer 203 only. For example, as shown in FIG. 23, above the heat generating portion 41 is a portion where a first layer 201, a second layer 202 and a third layer 203 are laminated. Further, as shown in FIG. 23, the portion between two heat generating portions 41 adjacent in the main scanning direction x is a portion consisting only of the third layer 203 .

The protective layer 2 of thermal print head B1 has a first region 21, as shown in FIGS. 20 and 23, like thermal print head A1. In the example shown in FIG. 20 , both ends of the first region 21 in the sub-scanning direction y overlap the heat generating portions 41 when viewed in the thickness direction z. In the first region 21, a plurality of first concave portions 22 and a plurality of first convex portions 23 are alternately arranged along the main scanning direction x. In the thermal print head B<b>1 , the plurality of first recesses 22 overlap portions of the protective layer 2 that are composed of only the third layer 203 without the first layer 201 and the second layer 202 . The plurality of first convex portions 23 overlap portions of the protective layer 2 in which the first layer 201, the second layer 202 and the third layer 203 are laminated in this order. Each first convex portion 23 is located in a region of the first region 21 overlapping with the heat generating portion 41 when viewed in the thickness direction z, and each first concave portion 22 is located in the first region 21 when viewed in the thickness direction z It is positioned in a region that does not overlap with the heat generating portion 41 .

Next, an example of a method for manufacturing the thermal print head B1 will be described below with reference to FIGS. 24 to 33. FIG.

FIG. 24 is a flow chart showing an example of a method for manufacturing the thermal print head B1. FIG. 25 is a fragmentary cross-sectional view showing one step of the method of manufacturing the thermal print head B1, and corresponds to FIG. 26 to 28, 30, 31 and 33 are plan views of essential parts showing one step of the method of manufacturing the thermal print head B1, and correspond to FIG. 29 and 32 are cross-sectional views of essential parts showing one step of the method of manufacturing the thermal print head B1, and correspond to FIG.

As shown in FIG. 24, the method for manufacturing the thermal printhead B1 includes a substrate preparation step S21, a glaze formation step S22, an electrode layer formation step S23, a resistor layer formation step S24, a protective layer primary formation step S25, and a laser processing step. It has S26, a protective layer secondary formation step S27, a singulation step S281, and an assembly step S282.

[Base material preparation step S21]
First, the base material 10 is prepared. The substrate preparation step S21 is performed in the same manner as the substrate preparation step S11.

[Glaze Forming Step S22]
Next, as shown in FIG. 25, a glaze layer 14 is formed. In the glaze forming step S22, after the partial glaze 15 is formed, the full glaze 16 is formed. Unlike the glaze forming step S12, the glaze forming step S22 does not perform the partial glaze division processing S122. Further, the glaze formation step S22 differs from the glaze formation step S12 in the formation range of the full-surface glaze 16 .

[Electrode layer forming step S23]
Next, as shown in FIG. 26, electrode layer 3 is formed. The electrode layer forming step S23 is performed in the same manner as the electrode layer forming step S13. The formation range of the electrode layer 3 is the same as the formation range shown in FIG.

[Resistor layer forming step S24]
Next, as shown in FIG. 27, resistor layer 4 is formed. The resistor layer forming step S24 is performed in the same manner as the resistor layer forming step S14. As can be understood from FIG. 27, the resistor layer 4 to be formed is strip-shaped with the main scanning direction x being the longitudinal direction when viewed in the thickness direction z.

[Protective layer primary formation step S25]
Next, as shown in FIGS. 28 and 29, the first layer 201 and the second layer 202 of the protective layer 2 are formed. As shown in FIG. 24, in the protective layer primary forming step S25, an oxide film forming process S251 and a protective film forming process S252 are sequentially performed.

In the oxide film forming process S251, an oxide film as the first layer 201 is formed on the entire upper surfaces of the glaze layer 14, the electrode layer 3 and the resistor layer 4 after the resistor layer forming step S24. The oxide film is deposited, for example, by sputtering. The formed oxide film is made of SiO ₂ , for example. The formation of the first layer 201 (oxide film formation step S251) may be formed by printing and baking a glass paste containing SiO ₂ .

In the protective film forming process S252, a protective film is formed as the second layer 202 on the first layer 201. FIG. The protective film is formed, for example, by a sputtering method or a CVD method. The formed protective film is made of SiC, for example.

[Laser processing step S26]
Next, the resistor layer 4 is divided into heat generating portions 41 by irradiation with laser light. In the laser processing step S26, for example, each of the plurality of regions R1 shown in FIG. Each of the plurality of regions R1 has a linear shape extending in the sub-scanning direction y when viewed in the thickness direction z. Each of the multiple regions R1 intersects the resistor layer 4 . In each region R1 irradiated with laser light, the second layer 202, the first layer 201 and the resistor layer 4 are partially removed, forming a plurality of grooves 29 as shown in FIGS. . As shown in FIG. 32, each of the plurality of grooves 29 extends from the second layer 202 to the resistor layer 4 in the thickness direction z. Further, as shown in FIG. 32, in each of the plurality of grooves 29, the second layer 202, the first layer 201 and the resistor layer 4 (each heat generating portion 41) are exposed, and the glaze layer 14 (partial glaze layer) is exposed. 15) is also exposed.

In the laser processing step S26, when dividing the resistor layer 4 into the heat generating portions 41, each groove 29 may be irradiated with laser light until it reaches the glaze layer 14 (partial glaze 15). In this case, the laser light may be irradiated until it penetrates the glaze layer 14 in the thickness direction z, or may be irradiated halfway in the thickness direction z of the glaze layer 14, or the glaze layer 14 (partial glaze 15) may be irradiated to such an extent that traces of irradiation of the laser beam are left.

[Protective layer secondary formation step S27]
Next, as shown in FIG. 33, the third layer 203 of the protective layer 2 is formed. As shown in FIG. 24, in the protective layer secondary formation step S27, an oxide film formation step S271 is performed.

In the oxide film forming process S271, an oxide film is formed as the third layer 203 on the second layer 202 after the laser processing step S26. The oxide film is formed by sputtering, for example, in the same manner as the oxide film forming process S251, and the formed oxide film is made of, for example, SiO ₂ . Thereby, the protective layer 2 having the first layer 201, the second layer 202 and the third layer 203 is formed. The formed oxide film (third layer 203) enters each groove 29 formed in the laser processing step S26. Therefore, the surface of the third layer 203 (the surface of the protective layer 2) is depressed in the thickness direction z in the region where the grooves 29 are present. That is, the protective layer 2 is formed with the first region 21 having the plurality of first concave portions 22 and the plurality of first convex portions 23 . The plurality of first concave portions 22 and the plurality of first convex portions 23 are alternately arranged along the main scanning direction x. In addition, the formed oxide film (third layer 203) is exposed on the sides of the second layer 202, the sides of the first layer 201, and the resistor layer 4 (each heat generating portion) exposed in each groove 29 after the laser processing step S26. 41), and covers the upper surface of the glaze layer 14 (partial glaze 15) exposed in the groove 29. As shown in FIG.

[Singulation step S281] [Assembly step S282]
After that, the thermal print head B1 shown in FIGS. 20 to 23 is manufactured through a separation step S281 and an assembly step S282. The singulation process S281 is performed in the same manner as the singulation process S161, and the assembly process S282 is performed in the same manner as the assembly process S162.

The actions and effects of the thermal print head B1 are as follows.

As with the thermal print head A1, the thermal print head B1 has a plurality of first concave portions 22 and a plurality of first convex portions arranged alternately along the main scanning direction x in the first region 21 of the protective layer 2. 23 are formed. Therefore, the thermal print head B1 can suppress the occurrence of the sticking phenomenon similarly to the thermal print head A1.

In the thermal print head B1, as in the thermal print head A1, the step d1 along the thickness direction z between each of the plurality of first concave portions 22 and each of the plurality of first convex portions 23 is equal to the thickness of the electrode layer 3. greater than the thickness t1 along the direction z. Therefore, like the thermal print head A1, the thermal print head B1 can appropriately secure a local gap between the print medium P1 and the protective layer 2 in order to suppress the sticking phenomenon.

In the thermal print head B<b>1 , the resistor layer 4 is divided for each heat generating portion 41 . With this configuration, steps are generated depending on the presence or absence of each heat generating portion 41 (resistor layer 4), and at least these steps cause unevenness (the plurality of first recesses 22 and the plurality of first protrusions 23) on the surface of the protective layer 2. It is formed. That is, the step d1 between each first concave portion 22 and each first convex portion 23 in the first region 21 has a size corresponding to the thickness of the resistor layer 4 (each heat generating portion 41). Also, the thickness of the resistor layer 4 is greater than the thickness t1 of the electrode layer 3 . Therefore, the thermal print head B<b>1 can form a step d<b>1 larger than the thickness t<b>1 of the electrode layer 3 on the surface of the protective layer 2 in the first region 21 . In particular, in the thermal print head B1, the first layer 201 and the second layer 202 of the protective layer 2 are partially removed when the resistor layer 4 is divided into the heat generating portions 41 (laser machining process). S26). For this reason, since a step difference is further generated depending on the presence or absence of the first layer 201 and the second layer 202, the step d1 between each first concave portion 22 and each first convex portion 23 can be increased.

In the thermal printhead B1, the protective layer 2 has a third layer 203. As shown in FIG. In the method for manufacturing the thermal print head B1, the laser processing step S26 is performed after the protective layer primary forming step S25. Therefore, the sides of the resistor layer 4 (each heat generating portion 41) are exposed in each groove 29 after the laser processing step S26. If the heat generating portions 41 are partially exposed in this way, there is a risk that unintended electrical connection may occur between the heat generating portions 41 . Therefore, the protective layer secondary formation step S27 (oxide film forming process S271) is performed after the laser processing step S26 to form the third layer 203 and to cover the heat generating portions 41 with the protective layer 2 . Thereby, the thermal print head B<b>1 can suppress unintended conduction of the heat generating portions 41 .

FIG. 34 shows a thermal print head B2 according to a modified example (first modified example) of the second embodiment. FIG. 34 is a plan view of the main part showing the thermal print head B2, and corresponds to FIG.

In the thermal print head B2, unlike the thermal print head B1, the resistor layer 4 is not divided into a plurality of heating portions 41. FIG. Such a thermal print head B1 is formed, for example, by partially removing the second layer 202 and the first layer 201 without dividing the resistor layer 4 in the laser processing step S26. Since the resistor layer 4 of the thermal print head B2 is not divided into a plurality of heat-generating portions 41, each strip-shaped portion 311 and each strip-shaped portion 321 are not separated in the sub-scanning direction y. As with A1, they may be alternately arranged along the main scanning direction x.

In the thermal print head B2 as well, the protective layer 2 has the first region 21 as in the thermal print heads A1 and B1. The first region 21 has a plurality of first concave portions 22 and a plurality of first convex portions 23 alternately arranged along the main scanning direction x. Therefore, the thermal print head B2 can suppress the occurrence of the sticking phenomenon similarly to the thermal print heads A1 and B1. Further, in the thermal print head B2, as can be understood from FIG. The thickness of the second layer 202 is greater than the thickness t<b>1 of the electrode layer 3 . Therefore, the thermal print head B2 can form an appropriate level difference d1 for suppressing the sticking phenomenon.

35 and 36 show a thermal print head B3 according to another modification (second modification) of the second embodiment. FIG. 35 is a cross-sectional view of the main part showing the thermal print head B3, corresponding to FIG. FIG. 36 is a flow chart showing an example of a method for manufacturing the thermal print head B3.

As shown in FIG. 35, the thermal print head B3 does not have the third layer 203 and is composed of the first layer 201 and the second layer 202, unlike the thermal print head B1. The first layer 201 and the second layer 202 are connected without being separated in the first region 21, as shown in FIG.

In the thermal print head B3, in the first region 21, there is a step between the portion where the heat generating portion 41 is arranged and the portion where the heat generating portion 41 is not arranged. Due to the steps, unevenness is formed on the surface of the protective layer 2 (the surface of the second layer 202). That is, a plurality of first concave portions 22 and a plurality of first convex portions 23 are formed in the first region 21 of the protective layer 2 . As can be understood from FIG. 35 , each first convex portion 23 is located in a region overlapping the heat generating portion 41 in the thickness direction z view in the first region 21 , and each first concave portion 22 is located in the first region 21 . It is located in a region that does not overlap with the heat generating portion 41 in the thickness direction z view.

Such a thermal print head B3 is formed through the steps shown in FIG. 36, for example. As shown in FIG. 36, the method for manufacturing the thermal print head B3 differs from the method for manufacturing the thermal print head B1 (see FIG. 24) in the following points. It is that the laser processing step S26 is performed after the resistor layer forming step S24 and before the protective layer primary forming step S25, and that there is no protective layer secondary forming step S27.

In the thermal print head B3, similarly to the thermal print heads A1 and B1, the protective layer 2 has first regions 21, and the first regions 21 are a plurality of regions alternately arranged along the main scanning direction x. It has a first concave portion 22 and a plurality of first convex portions 23 . Therefore, the thermal print head B3 can suppress the sticking phenomenon similarly to the thermal print heads A1 and B1. Further, in the thermal print head B3, as can be understood from FIG. 35, the step d1 between each first concave portion 22 and each first convex portion 23 corresponding to the thickness of the resistor layer 4 (each heat generating portion 41) is occur. Therefore, the thermal print head B3 can form an appropriate level difference d1 for suppressing the sticking phenomenon.

37 and 38 show a thermal print head B4 according to another modification (third modification) of the second embodiment. FIG. 37 is a cross-sectional view of the main part showing the thermal print head B4, corresponding to FIG. FIG. 38 is a flow chart showing an example of a method for manufacturing the thermal print head B4.

As shown in FIG. 37, in the thermal print head B4, the protective layer 2 does not have the third layer 203 and consists of the first layer 201 and the second layer 202, like the thermal print head B3. However, as shown in FIG. 37, in the thermal print head B4, like the thermal print head B3, the second layer 202 is connected without being divided in the first region 21, but unlike the thermal print head B3, The first layer 201 is divided in the first region 21 in the same manner as the heat generating portion 41 .

In the thermal print head B4, in the first region 21, there is a step between the portion where the heat generating portion 41 is arranged and the portion where the heat generating portion 41 is not arranged. Due to the steps, unevenness is formed on the surface of the protective layer 2 (the surface of the second layer 202). That is, a plurality of first concave portions 22 and a plurality of first convex portions 23 are formed in the first region 21 of the protective layer 2 . As can be understood from FIG. 37 , each first convex portion 23 is positioned in a region overlapping the heat generating portion 41 in the thickness direction z view in the first region 21 , and each first concave portion 22 is located in the first region 21 . It is located in a region that does not overlap with the heat generating portion 41 in the thickness direction z view.

Such a thermal print head B4 is formed through the steps shown in FIG. 38, for example. As shown in FIG. 38, the method for manufacturing the thermal print head B4 differs from the method for manufacturing the thermal print head B1 (see FIG. 24) in the following points. That is, the protective film forming process S252 is performed in the protective layer secondary forming process S27, and the protective layer secondary forming process S27 does not include the oxide film forming process S271.

In the thermal print head B4, similarly to each of the thermal print heads A1 and B1, the protective layer 2 has first regions 21, and the first regions 21 are a plurality of regions alternately arranged along the main scanning direction x. It has a first concave portion 22 and a plurality of first convex portions 23 . Therefore, the thermal print head B4 can suppress the occurrence of the sticking phenomenon similarly to the thermal print heads A1 and B1. Moreover, in the thermal print head B4, as can be understood from FIG. A step d1 from the portion 23 is generated. Therefore, the thermal print head B4 can form an appropriate level difference d1 for suppressing the sticking phenomenon.

[Third embodiment]
39 to 42 show a thermal print head C1 according to the third embodiment. FIG. 39 is a plan view showing the thermal print head C1. FIG. 40 is a plan view of the main part, enlarging a part of FIG. 39, and FIG. 41 is a cross-sectional view taken along line XLI-XLI of FIG. 42 is a cross-sectional view along line XLII-XLII in FIG. 40. FIG.

The thermal print head C1 differs from each of the thermal print heads A1 and B1 in each configuration of the head substrate 1, the protective layer 2, the electrode layer 3, and the resistor layer 4. FIG. In the thermal print head C1 shown in FIG. 39, each driver IC 7 is arranged on the connection substrate 5, but each driver IC 7 is arranged on the head substrate 1 as in the thermal print heads A1 and B1. may

A head substrate 1 of the thermal print head C1 has a base material 10 and an insulating layer 19. As shown in FIG.

The base material 10 is made of a single crystal semiconductor. The single crystal semiconductor is Si (silicon), for example. Therefore, in the thermal print head C1, the constituent material of the substrate 10 is different from those of the thermal print heads A1 and B1. Substrate 10 has a major surface 11 and a back surface 12 . The main surface 11 and the back surface 12 are spaced apart in the thickness direction z and face opposite sides in the thickness direction z.

The base material 10 further has a convex portion 13 . The convex portion 13 protrudes from the main surface 11 in the thickness direction z and extends long in the main scanning direction x. In the illustrated example, the convex portion 13 is formed downstream of the base material 10 in the sub-scanning direction y. Since the convex portion 13 is a part of the base material 10, it is made of Si, which is a single crystal semiconductor. It should be noted that the projections 13 may not be formed on the base material 10 .

The convex portion 13 has a top portion 130, a pair of first inclined portions 131A and 131B, and a pair of second inclined portions 132A and 132B.

The top portion 130 is the portion of the convex portion 13 that is the longest from the main surface 11 . Top portion 130 is, for example, a plane substantially parallel to main surface 11 . The top portion 130 has an elongated rectangular shape elongated in the main scanning direction x when viewed in the thickness direction z.

The pair of first inclined portions 131A and 131B are connected to both sides of the top portion 130 in the sub-scanning direction y, as shown in FIG. The first inclined portion 131A is connected to the top portion 130 from the upstream side in the sub-scanning direction y. The first inclined portion 131B connects to the top portion 130 from the downstream side in the sub-scanning direction y. Each of the pair of first inclined portions 131A and 131B is inclined at an angle α1 with respect to the main surface 11 (inclined at a first inclination angle α1). Each of the pair of first inclined portions 131A and 131B is an elongated rectangular plane elongated in the main scanning direction x when viewed in the thickness direction z. The convex portion 13 may have inclined portions (not shown) connected to the pair of first inclined portions 131A and 131B and adjacent to both ends of the top portion 130 in the main scanning direction x.

As shown in FIG. 41, the pair of second inclined portions 132A and 132B are connected to the pair of first inclined portions 131A and 131B from the side opposite to the top portion 130 in the sub-scanning direction y. The second inclined portion 132A is sandwiched between the first inclined portion 131A and the main surface 11 in the sub-scanning direction y. The second inclined portion 132A connects to the first inclined portion 131A from the upstream side in the sub-scanning direction y, and connects to the main surface 11 from the downstream side in the sub-scanning direction y. The second inclined portion 132B is sandwiched between the first inclined portion 131B and the main surface 11 in the sub-scanning direction y. The second inclined portion 132B connects to the first inclined portion 131B from the downstream side in the sub-scanning direction y, and connects to the main surface 11 from the upstream side in the sub-scanning direction y. Each of the pair of second inclined portions 132A and 132B is inclined at an angle α2 (inclined at a second inclination angle α2) with respect to the main surface 11 . Angle α2 is greater than angle α1. Each of the pair of second inclined portions 132A and 132B is an elongated rectangular plane elongated in the main scanning direction x when viewed in the thickness direction z. The pair of second inclined portions 132A and 132B are connected to the main surface 11 respectively. The convex portion 13 may have inclined portions (not shown) connected to the pair of second inclined portions 132A and 132B and positioned outside in the main scanning direction x on both ends of the top portion 130 in the main scanning direction x. . The convex portion 13 may have the pair of second inclined portions 132A and 132B connected to the top portion 130 without the pair of first inclined portions 131A and 131B.

In the head substrate 1, the main surface 11 is the (100) plane. According to a manufacturing method example described later, the angle α1 (see FIG. 41) of each of the first inclined portions 131A and 131B with respect to the main surface 11 is, for example, 30.1 degrees, and each of the second inclined portions 132A and 132A with respect to the main surface 11 The angle α2 of 132B (see FIG. 41) is, for example, 54.7 degrees. The thickness direction z dimension of the convex portion 13 (the amount of protrusion along the thickness direction z from the main surface 11) is, for example, 150 μm or more and 300 μm or less (about 170 μm in one example).

The insulating layer 19 covers the main surface 11 and the projections 13, as shown in FIGS. The insulating layer 19 serves to insulate the main surface 11 side of the base material 10 more reliably. The insulating layer 19 is made of an insulating material. As the insulating material, for example, SiO ₂ (TEOS-SiO ₂ ) formed by using TEOS (tetraethyl orthosilicate) as a raw material gas is employed. Instead of TEOS-SiO ₂ , for example, SiO ₂ or SiN (silicon nitride) deposited by other methods may be employed. Although the thickness of the insulating layer 19 is not particularly limited, it is about 15 μm in one example.

The insulating layer 19 has a second region 191 . As understood from FIGS. 40 and 42, the second region 191 overlaps the first region 21 when viewed in the thickness direction z. The second region 191 has a plurality of second concave portions 192 and a plurality of second convex portions 193 . The plurality of second concave portions 192 and the plurality of second convex portions 193 are alternately arranged along the main scanning direction x.

Each of the plurality of second recesses 192 is adjacent to each of the plurality of heat generating portions 41 when viewed in the thickness direction z. Each second concave portion 192 is sandwiched between two heat generating portions 41 adjacent to each other in the main scanning direction x. Each heat generating portion 41 (resistor layer 4 ) is not formed on each second recess 192 . Each second recess 192 is formed by partially removing the insulating layer 19 in a manufacturing method to be described later. Each second concave portion 192 does not overlap the resistor layer 4 when viewed in the thickness direction z. Each of the plurality of second convex portions 193 overlaps the heat generating portion 41 when viewed in the thickness direction z. Each heat generating portion 41 (resistor layer 4 ) is formed on each second convex portion 193 . A step d2 (see FIG. 42) between each second concave portion 192 and each second convex portion 193 along the thickness direction z is preferably larger than the thickness t1 of the electrode layer 3, for example.

The electrode layer 3 is supported by the head substrate 1, and is laminated on the resistor layer 4 as shown in FIG. 41 in this embodiment. The electrode layer 3 has a common electrode 31 , multiple individual electrodes 32 and multiple relay electrodes 33 .

Each of the plurality of relay electrodes 33 includes two belt-shaped portions 331 and a connecting portion 332, as shown in FIG. The two strip-shaped portions 331 are strip-shaped extending in the sub-scanning direction y. The two band-shaped portions 331 are spaced apart in the main scanning direction x while being arranged substantially parallel to each other. Each of the two belt-shaped portions 331 is connected to the adjacent exothermic portion 41 . In the example shown in FIG. 40, each of the two band-shaped portions 331 is connected to each heat generating portion 41 from the downstream side in the sub-scanning direction y. Each dimension in the main scanning direction x of the two band-shaped portions 331 is substantially the same. The connecting portion 332 is connected to an end connected to each of the two band-shaped portions 331 and an end opposite to the sub-scanning direction y. The connecting portion 332 has a strip shape extending in the main scanning direction x. The plurality of relay electrodes 33 are arranged at equal pitches in the main scanning direction x. Each of the plurality of relay electrodes 33 is positioned downstream of the plurality of heat generating portions 41 in the sub-scanning direction y.

The common electrode 31 includes a plurality of straight portions 313, a plurality of branch portions 314, a plurality of strip portions 315, and a connecting portion 316, as shown in FIG. Each of the plurality of orthogonal portions 313 has a strip shape extending in the sub-scanning direction y. The plurality of orthogonal portions 313 are arranged at equal pitches in the main scanning direction x. A branching portion 314 and two band-like portions 315 are provided on each tip side (downstream side in the sub-scanning direction y) of the plurality of orthogonal portions 313 . The two belt-shaped portions 315 are connected to adjacent heat generating portions 41 respectively. In the example shown in FIG. 40, each of the two band-shaped portions 315 is connected to the heat generating portion 41 from the upstream side in the sub-scanning direction y. The dimension of each band-shaped portion 315 in the main scanning direction x is substantially the same as the dimension of each band-shaped portion 331 in the main scanning direction x. Also, the band-shaped portion 315 overlaps the band-shaped portion 331 when viewed in the sub-scanning direction y. A plurality of branch portions 314 are connected to the tip of each straight portion 313 respectively. The straight portions 313 are connected to the ends of the plurality of branch portions 314 opposite to the ends connected to the two strip portions 315 in the sub-scanning direction y. Each of the two band-shaped portions 315 is connected to the heat generating portion 41 from the upstream side in the sub-scanning direction y. The connecting portion 316 is positioned on the base end side (upstream side in the sub-scanning direction y) of the plurality of orthogonal portions 313 and extends along the main scanning direction x. A plurality of direct portions 313 are connected to the connecting portion 316 respectively. The connecting portion 316 is connected to the connector 59 via the wire 61 and wiring of the connection board 5, and is applied with a driving voltage.

The plurality of individual electrodes 32 are spaced apart in the main scanning direction x, as shown in FIG. The band-shaped portion 321 of each individual electrode 32 is positioned upstream of the heat generating portion 41 in the sub-scanning direction y. The band-shaped portion 321 of each individual electrode 32 is connected to the heat generating portion 41 on the tip side (downstream side in the sub-scanning direction y). The dimension of each band-shaped portion 321 in the main scanning direction x is substantially the same as the dimension of each band-shaped portion 331 in the main scanning direction x. The downstream end portion of each band-shaped portion 321 in the sub-scanning direction y overlaps each band-shaped portion 331 when viewed in the sub-scanning direction y.

In the thermal print head C1, as shown in FIG. 40, each straight portion 313 is sandwiched between strip portions 321 of two individual electrodes 32. As shown in FIG. The heat-generating portion 41 to which one of the two strip-shaped portions 331 of each relay electrode 33 is connected is connected to the strip-shaped portion 315, and the heat-generating portion 41 to which the other of the two strip-shaped portions 331 of the relay electrode 33 is connected is , to one of the strip portions 321 of the plurality of individual electrodes 32 . Therefore, when each individual electrode 32 is energized, current flows through the heat generating portion 41 connected thereto and the heat generating portion 41 connected to the heat generating portion 41 via the relay electrode 33, and these heat generating portions 41 Fever. That is, the two heat generating portions 41 generate heat at the same time.

The electrode layer 3 (the common electrode 31, the plurality of individual electrodes 32 and the plurality of relay electrodes 33) is composed of a first conductor layer 301 and a second conductor layer 302 laminated in the thickness direction z, as understood from FIG. is composed of

The first conductor layer 301 is formed on the resistor layer 4 . The first conductor layer 301 is made of a material having a resistance lower than that of the resistor layer 4 and a resistance higher than that of the second conductor layer 302 . Ti (titanium), for example, is used as a constituent material of the first conductor layer 301, but instead of Ti, Ta, Ga, Sn, PtIr, Pt, TI (thallium), V (vanadium), Cr, or the like may be used. may be adopted. The method of forming the first conductor layer 301 is not particularly limited, but may be formed by, for example, a sputtering method, a CVD method, or plating, and may be appropriately selected depending on the constituent material employed. For example, when the constituent material of the first conductor layer 301 is Ti, the first conductor layer 301 is formed by a sputtering method. Although the thickness of the first conductor layer 301 is not particularly limited, it is about 30 nm in one example.

The second conductor layer 302 is formed on the first conductor layer 301 . The second conductor layer 302 partially covers the first conductor layer 301 . Therefore, the first conductor layer 301 has a portion exposed from the second conductor layer 302 . The second conductor layer 302 is made of a material with lower resistance than the resistor layer 4 and the first conductor layer 301 . Also, the second conductor layer 302 is made of a material having higher thermal conductivity than the first conductor layer 301 . Cu alloy, Al, Al alloy, Au, Ag, Ni, W (tungsten), or the like may be used instead of Cu, for example, as the constituent material of the second conductor layer 302 . The method of forming the second conductor layer 302 is not particularly limited, but may be formed by, for example, a sputtering method, a CVD method, or plating, and may be appropriately selected depending on the constituent material employed. For example, when the constituent material of the second conductor layer 302 is Cu, the second conductor layer 302 is formed by a sputtering method. When the constituent material of the second conductor layer 302 is Au, Ag, or Ni, it is generally formed by plating. In this case, the second conductor layer 302 includes a seed layer (eg, Cu). You can stay. The second conductor layer 302 is thicker than the first conductor layer 301 . The thickness of the second conductor layer 302 depends on the material used, the value of the current flowing through the electrode layer 3, and the like. Although the thickness of the second conductor layer 302 is not particularly limited, it is about 800 nm in one example.

The resistor layer 4 is supported by the head substrate 1 via the insulating layer 19, as shown in FIGS. TaN (tantalum nitride), for example, is used as a constituent material of the resistor layer 4, but instead of TaN, TaSiO ₂ , TiON, PolySi, Ta ₂ O ₅ , RuO ₂ , RuTiO, TaSiN, or the like may be used. good too. The method of forming the resistor layer 4 is not particularly limited, but may be formed by, for example, a sputtering method, a CVD method, or plating, and may be appropriately selected depending on the constituent material employed. For example, when the constituent material of the resistor layer 4 is TaN, the resistor layer 4 is formed by a sputtering method. Although the thickness of the resistor layer 4 is not particularly limited, it is about 60 nm in one example.

The resistor layer 4 of the thermal print head C1 is divided into a plurality of heat generating portions 41, similarly to the resistor layer 4 of the thermal print head B1. Each heat-generating portion 41 is formed across each strip-shaped portion 331 and each strip-shaped portion 321 or across each strip-shaped portion 331 and each strip-shaped portion 315 when viewed in the thickness direction z.

Protective layer 2 is made of SiN, for example. The constituent material of the protective layer 2 may be SiO ₂ , SiC, AlN, etc., instead of SiN. The protective layer 2 is composed of a single layer or multiple layers containing the aforementioned insulating material. The thickness of the protective layer 2 (the thickness of the portion in contact with the insulating layer 19) is not particularly limited, but is about 3.2 μm in one example.

The protective layer 2 of the thermal printhead C1 has a first region 21, as shown in FIG. 42, like the protective layers 2 of the thermal printheads A1 and B1. In the example shown in FIG. 40, when viewed in the thickness direction z, both ends of the first region 21 in the sub-scanning direction y are the second concave portions 192, the second convex portions 193, and the resistor layers 4 (heat generating portions). 41). In the first region 21, a plurality of first concave portions 22 and a plurality of first convex portions 23 are alternately arranged along the main scanning direction x. In the thermal print head C1, the plurality of first recesses 22 respectively overlap the second recesses 192 when viewed in the thickness direction z. Also, the plurality of first protrusions 23 respectively overlap the second protrusions 193 when viewed in the thickness direction z. The first region 21 substantially overlaps the second region 191 when viewed in the thickness direction z. As can be understood from FIG. 42 , each first convex portion 23 is located in a region of the first region 21 that overlaps with the heat generating portion 41 when viewed in the thickness direction z, and each first concave portion 22 is located in the first region 21 . It is positioned in a region that does not overlap with the heat generating portion 41 as viewed in the thickness direction z.

Next, an example of a method for manufacturing the thermal print head C1 will be described with reference to FIGS. 43 to 55. FIG.

FIG. 43 is a flow chart showing an example of a method for manufacturing the thermal print head C1. 44 to 47, 49, and 51 to 53 are cross-sectional views of essential parts showing one step of the method of manufacturing the thermal print head C1, and correspond to the cross section of FIG. 48, 50, 54 and 55 are cross-sectional views of essential parts showing one step of the method of manufacturing the thermal print head C1, and correspond to the cross-section of FIG.

As shown in FIG. 43, the method of manufacturing the thermal print head C1 includes a substrate preparation step S31, a substrate processing step S32, an insulating layer forming step S33, a resistor film forming step S34, a wiring film forming step S35, and a removing step S36. , an insulating layer processing step S37, a protective layer forming step S38, a singulation step S391, and an assembly step S392.

[Base material preparation step S31]
First, as shown in FIG. 44, a base material 10K is prepared. The substrate 10K is made of a single crystal semiconductor and is, for example, a portion of a substantially circular Si wafer. A single Si wafer includes a plurality of substrates 10K. In the following figures, one base material 10K (head substrate 1), which is part of the Si wafer and corresponds to one thermal print head C1, may be illustrated. Although the thickness of the base material 10K (in other words, the thickness of the Si wafer) is not particularly limited, it is, for example, about 725 μm in this embodiment. As shown in FIG. 44, the base material 10K has a main surface 11K and a back surface 12K facing opposite sides. The main surface 11K is the (100) plane.

[Base material processing step S32]
Next, as shown in FIGS. 45 and 46, the base material 10K is processed to form the projections 13 on the base material 10K. In the base material processing step S32, etching is performed twice.

In the first etching, after the main surface 11K is covered with a predetermined mask layer, anisotropic etching is performed using KOH (potassium hydroxide), for example. Although TMAH (tetramethylammonium hydroxide) may be used instead of KOH as a chemical for this anisotropic etching, the processing speed (etching speed) is faster when KOH is used. After that, the mask layer is removed. As a result, as shown in FIG. 45, a convex portion 13K is formed on the base material 10K. The convex portion 13K protrudes from the main surface 11K and extends long in the main scanning direction x. The convex portion 13K has a top portion 130K and a pair of inclined portions 132K. The top portion 130K is a plane parallel to the main surface 11K and is the same (100) plane as the main surface 11K. The top portion 130K is the portion that was covered with the mask layer. The pair of inclined portions 132K are located on both sides of the top portion 130K in the sub-scanning direction y, and are interposed between the top portion 130K and the main surface 11K. Each of the pair of inclined portions 132K is a plane inclined with respect to the top portion 130K and the main surface 11K. The angle formed by each of the pair of inclined portions 132K, the main surface 11K and the top portion 130K is 54.7 degrees.

The second etching is anisotropic etching using TMAH, for example. The chemical used in this anisotropic etching may be KOH instead of TMAH, but the surface formed by etching (for example, a pair of first inclined portions 131A and 131B described later) is smoother when TMAH is used. become a good side. By this anisotropic etching, the base material 10K becomes the head substrate 1 having the main surface 11, the back surface 12 and the projections 13, as shown in FIG. The convex portion 13 has a top portion 130, a pair of first inclined portions 131A and 131B, and a pair of second inclined portions 132A and 132B. The top portion 130 is the portion that was the top portion 130K, and the pair of second inclined portions 132A and 132B are the portions that were the pair of inclined portions 132K. The pair of first inclined portions 131A and 131B are portions where the boundary between the top portion 130K and the pair of inclined portions 132K is etched by TMAH. The angle α1 (see FIG. 46) of each first inclined portion 131A, 131B with respect to the main surface 11 is 30.1 degrees, and the angle α2 (see FIG. 46) of each second inclined portion 132A, 132B with respect to the main surface 11 is , 54.7 degrees.

[Insulating layer forming step S33]
Next, as shown in FIGS. 47 and 48, insulating layer 19 is formed. The insulating layer 19 is formed by depositing SiO ₂ formed using TEOS as a source gas on the substrate 10 using, for example, CVD. The method for forming the insulating layer 19 is not limited to this. The formed insulating layer 19 covers the entire main surface 11 and the protrusions 13 .

[Resistor Film Forming Step S34]
Next, as shown in FIGS. 49 and 50, a resistor film 4K is formed. In the resistor film forming step S34, a TaN thin film is formed on the insulating layer 19 by sputtering, for example. The method of forming the resistor film 4K is not limited to this.

[Wiring film forming step S35]
Next, as shown in FIGS. 51 and 52, a wiring film 3K is formed. The wiring film forming step S35 has a first film forming process S351 and a second film forming process S352.

In the first film forming process S351, as shown in FIG. 51, a first conductor film 301K is formed on the resistor film 4K. The first conductor film 301K is formed by sputtering, for example. The first conductor film 301K is a thin film made of Ti, for example. At this time, the first conductor film 301K covers substantially the entire surface of the resistor film 4K.

In the second film forming process S352, as shown in FIG. 52, the second conductor film 302K is formed on the first conductor film 301K. The second conductor film 302K is formed by, for example, plating or sputtering. The second conductor film 302K is made of Cu, for example. At this time, the second conductor film 302K covers substantially the entire surface of the first conductor film 301K.

[Removal step S36]
Next, as shown in FIGS. 53 and 54, the second conductor film 302K, the first conductor film 301K and the resistor film 4K are partially removed as appropriate. As shown in FIG. 43, the removal step S36 has a first partial removal process S361, a second partial removal process S362, and a third partial removal process S363.

In the first partial removal process S361, the second conductor film 302K is partially removed. In the second partial removal process S362, the first conductor film 301K is partially removed. In the third partial removal process S363, partial removal of the resistor film 4K is performed. The first partial removal processing S361, the second partial removal processing S362, and the third partial removal processing S363 are each performed by etching, for example. The second conductor layer 302 is formed by the first partial removal process S361, the first conductor layer 301 is formed by the second partial removal process S362, and the resistor layer 4 is formed by the third partial removal process S363. . The third partial removal process S363 may be performed before the first partial removal process S361 and the second partial removal process S362. The formed first conductor layer 301 and second conductor layer 302 constitute the electrode layer 3 , and the electrode layer 3 has a common electrode 31 , a plurality of individual electrodes 32 and a plurality of relay electrodes 33 . The formed resistor layer 4 has a plurality of heat generating portions 41 and is divided into each heat generating portion 41 .

[Insulating layer processing step S37]
Next, as shown in FIG. 55, the insulating layer 19 is processed. In the insulating layer processing step S37, for example, resist formation by photolithography, partial removal of the insulating layer 19 by etching, and resist removal are sequentially performed. A plurality of second concave portions 192 and a plurality of second convex portions 193 are formed in the second region 191 of the insulating layer 19 by the insulating layer processing step S37. As shown in FIG. 55, each of the plurality of second concave portions 192 is formed between the heat generating portions 41 adjacent to each other in the main scanning direction x. Also, the plurality of second convex portions 193 are formed below each heat generating portion 41 . Therefore, in the second region 191, the plurality of second concave portions 192 and the plurality of second convex portions 193 are alternately arranged along the main scanning direction x.

[Protective layer forming step S38]
Next, protective layer 2 is formed. Formation of protective layer 2 is performed by depositing SiN on insulating layer 19, electrode layer 3 (first conductor layer 301 and second conductor layer 302) and resistor layer 4 using CVD, for example. Moreover, each bonding part 322 is exposed from the protective layer 2 by partially removing the protective layer 2 by etching or the like. Thereby, the protective layer 2 shown in FIGS. 40 to 42 is formed. Concavities and convexities are formed on the surface of the protective layer 2 to be formed along the concavities and convexities formed by the second concave portions 192 and the second convex portions 193 . That is, the protective layer 2 is formed with the first region 21 having the plurality of first concave portions 22 and the plurality of first convex portions 23 . The plurality of first concave portions 22 and the plurality of first convex portions 23 are alternately arranged along the main scanning direction x.

[Singulation step S391] [Assembly step S392]
After that, the thermal print head C1 shown in FIGS. 39 to 42 is manufactured through the singulation process S391 and the assembly process S392. The singulation step S391 is performed in the same manner as the singulation steps S161 and S281, and the assembly step S392 is performed in the same manner as the assembly steps S162 and S282.

The actions and effects of the thermal print head C1 are as follows.

The thermal print head C1, like the thermal print heads A1 and B1, has a plurality of first recesses 22 and a plurality of first recesses 22 and 22 arranged alternately along the main scanning direction x in the first region 21 of the protective layer 2. 1 convex part 23 is formed. Therefore, the thermal print head C1 can suppress the sticking phenomenon similarly to the thermal print heads A1 and B1.

In the thermal print head C1, as in the thermal print heads A1 and B1, the step d1 between each of the plurality of first concave portions 22 and each of the plurality of first convex portions 23 along the thickness direction z is the electrode layer 3 is greater than the thickness t1 along the thickness direction z of the . Therefore, the thermal print head C1 can appropriately secure a local gap between the print medium P1 and the protective layer 2 in order to suppress the sticking phenomenon in the same manner as the thermal print heads A1 and B1. can.

In the thermal printhead C1, the insulating layer 19 has a second region 191. As shown in FIG. The second region 191 has a plurality of second recesses 192 and a plurality of second protrusions 193, and the plurality of second recesses 192 and the plurality of second protrusions 193 are alternately arranged along the main scanning direction x. It is The second region 191 overlaps the first region 21 when viewed in the thickness direction z. According to this configuration, the surface of the insulating layer 19 in the second region 191 undulates along the main scanning direction x. These undulations form irregularities (the plurality of first concave portions 22 and the plurality of first convex portions 23 ) on the surface of the protective layer 2 . That is, the step d1 between each first concave portion 22 and each first convex portion 23 in the first region 21 has a size corresponding to the step d2 between each second concave portion 192 and each second convex portion 193 . Therefore, the thermal print head C1 forms a step d1 larger than the thickness t1 of the electrode layer 3 on the surface of the protective layer 2 in the first region 21 by making the step d2 larger than the thickness t1 of the electrode layer 3. can be formed. In addition, in the thermal print head C<b>1 , the resistor layer 4 (each heat generating portion 41 ) is formed on each second convex portion 193 . Therefore, it is possible to make the step d1 larger than the thickness t1 of the electrode layer 3 even if the step d2 is smaller than the thickness t1 of the electrode layer 3 . However, if the step d2 is made larger than the thickness t1 of the electrode layer 3, the local gap between the protective layer 2 and the print medium P1 can be made larger, which is preferable for suppressing the sticking phenomenon.

[Fourth embodiment]
56 to 58 show a thermal print head D1 according to the fourth embodiment. FIG. 56 is a plan view showing the main part of the thermal print head D1, and corresponds to FIG. In FIG. 56, the first area 21 is indicated by an imaginary line (chain two-dot line). FIG. 57 is a cross-sectional view of essential parts along the LVII--LVII line in FIG. FIG. 58 is a cross-sectional view of essential parts taken along line LVIII--LVIII in FIG.

Thermal print head D1 differs from thermal print head A1 in that resistor layer 4 is formed below electrode layer 3 . Although the glaze layer 14 of the head substrate 1 does not have the partial glaze 15 in the examples shown in FIGS. .

As can be seen from FIG. 56, the electrode layer 3 has portions similar to those of the electrode layer 3 of the thermal print head A1 (see FIG. 4). Each strip 311 and each strip 321 are partially formed on the resistor layer 4 . Each strip-shaped portion 311 and each strip-shaped portion 321 are alternately arranged along the main scanning direction x on the resistor layer 4 . Each heat-generating portion 41 is positioned between each strip-shaped portion 311 and each strip-shaped portion 321 when viewed in the thickness direction z.

Electrode layer 3 has seed layer 303 and plating layer 304 . Seed layer 303 is formed by stacking, for example, a layer made of Ti and a layer made of Cu. Unlike this configuration example of the seed layer 303, the seed layer 303 may be composed only of a layer made of Cu. The plated layer 304 is made of Cu or Cu alloy, for example. Plated layer 304 is formed, for example, by electrolytic plating. A plating layer 304 is formed on the seed layer 303 .

The thickness t2 (see FIG. 58) of the electrode layer 3 of the thermal print head D1 is larger than the thickness t1 of the electrode layer 3 of the thermal print heads A1, B1 and C1. Since the plating layer 304 is formed by electroplating, the electrode layer 3 of the thermal print head D1 can be easily made thicker than when it is formed by a sputtering method, a CVD method, thick film printing, or the like. Therefore, in the thermal print head D1, the step along the thickness direction z between the portion where the electrode layer 3 is formed and the portion where the electrode layer 3 is not formed depends on the presence or absence of the electrode layer 3 in the thermal print head A1. larger than the resulting step.

The protective layer 2 of the thermal print head D1 has a first region 21, as shown in FIG. 58, like the protective layers 2 of the thermal print heads A1, B1 and C1. In the example shown in FIG. 56, both ends of the first region 21 in the sub-scanning direction y overlap with the resistor layer 4 (each heat generating portion 41) when viewed in the thickness direction z. In the first region 21, a plurality of first concave portions 22 and a plurality of first convex portions 23 are alternately arranged along the main scanning direction x. In the thermal print head D1, unevenness (a plurality of first recesses 22 and a plurality of first protrusions 23) is formed on the surface of the protective layer 2 in the first regions 21 due to steps caused by the presence or absence of the electrode layer 3. FIG. As can be understood from FIG. 58, each first concave portion 22 is located in a region of the first region 21 that does not overlap the electrode layer 3 when viewed in the thickness direction z, and each first convex portion 23 is located in the first region. 21 in a region that overlaps with the electrode layer 3 when viewed in the thickness direction z.

Next, an example of a method for manufacturing the thermal print head D1 will be described below with reference to FIGS. 59 to 67. FIG.

FIG. 59 is a flow chart showing an example of a method for manufacturing the thermal print head D1. 60, 62, 64 and 66 are cross-sectional views of essential parts showing one step of the method of manufacturing the thermal print head D1, and correspond to FIG. 61, 63, 65 and 67 are cross-sectional views of essential parts showing one step of the method of manufacturing the thermal print head D1, and correspond to FIG.

As shown in FIG. 59, the method of manufacturing the thermal print head D1 includes a substrate preparation step S41, a glaze formation step S42, a resistor layer formation step S43, an electrode layer formation step S44, a protective layer formation step S45, and a singulation step. It has S461 and assembly step S462.

[Base material preparation step S41]
First, the base material 10 is prepared. The substrate preparation step S41 is performed in the same manner as the substrate preparation steps S11 and S21.

[Glaze Forming Step S42]
Next, a glaze layer 14 is formed. In the glaze forming step S42, a full-surface glaze 16 is formed on substantially the entire main surface 11. As shown in FIG. That is, in the glaze formation step S42, the above-described entire surface glaze formation processing S123 is performed. The formed glaze layer 14 consists of the full glaze 16 and does not have the partial glaze 15 .

[Resistor layer forming step S43]
Next, as shown in FIGS. 60 and 61, resistor layer 4 is formed. The resistor layer forming step S43 is performed in the same manner as the resistor layer forming step S24. The resistor layer 4 to be formed has a band-like shape whose longitudinal direction is the main scanning direction x when viewed in the thickness direction z (see FIG. 56).

[Electrode layer forming step S44]
Next, the electrode layer 3 is formed. As shown in FIG. 59, in the electrode layer forming step S44, a seed layer forming process S441, a plated layer forming process S442, and a removing process S443 are sequentially performed.

In the seed layer forming process S441, as shown in FIGS. 62 and 63, a seed layer 303 is formed. Seed layer 303 has, for example, a Ti layer and a Cu layer laminated together. Specifically, in the seed layer forming process S441, after forming a Ti layer by sputtering, for example, a Cu layer is formed in contact with the Ti layer by sputtering. Unlike this technique, in the seed layer forming process S441, as the seed layer 303, a Cu layer may be formed by electroless plating.

In the plated layer forming process S442, as shown in FIGS. 64 and 65, the plated layer 304 is formed by electroplating. The plated layer 304 is made of Cu or Cu alloy, for example. Specifically, in the plating layer forming process S442, for example, a resist (not shown) for forming the plating layer 304 is formed by photolithography. In forming the resist, a photosensitive resist is applied so as to cover the entire surface of the seed layer 303, and patterning is performed by exposing and developing the photosensitive resist. This patterning exposes a portion of the seed layer 303 (the portion forming the plating layer 304). Then, a plating layer 304 is formed on the seed layer 303 exposed from the resist by electroplating using the seed layer 303 as a conductive path. Then, the resist is removed. Thus, plating layer 304 shown in FIGS. 64 and 65 is formed.

In the removing process S443, as shown in FIGS. 66 and 67, the seed layer 303 exposed from the plating layer 304 is removed. In the removing process S443, the entire surface including the plating layer 304 is etched. Thereby, an electrode layer 3 having a common electrode 31 and a plurality of individual electrodes 32 is formed. At this time, as shown in FIG. 67, unevenness is formed in the thickness direction z by portions where the electrode layer 3 is formed and portions where the electrode layer 3 is not formed.

[Protective layer forming step S45]
Next, protective layer 2 is formed. The protective layer forming step S45 is performed in the same manner as the protective layer forming step S15. On the surface of the protective layer 2 to be formed, unevenness is formed along the unevenness formed by the presence or absence of the electrode layer 3 . That is, the protective layer 2 is formed with the first region 21 having the plurality of first concave portions 22 and the plurality of first convex portions 23 . The plurality of first concave portions 22 and the plurality of first convex portions 23 are alternately arranged along the main scanning direction x.

[Singulation step S461] [Assembly step S462]
After that, through the singulation process S461 and the assembly process S462, the thermal print head D1 shown in FIGS. 56 to 58 is manufactured. The singulation step S461 is performed in the same manner as the singulation steps S161, S281 and S391, and the assembly step S462 is performed in the same manner as the assembly steps S162, S282 and S392.

The actions and effects of the thermal print head D1 are as follows.

The thermal print head D1, like the thermal print heads A1, B1 and C1, has a plurality of first recesses 22 and a plurality of recesses 22 and 22 alternately arranged in the first region 21 of the protective layer 2 along the main scanning direction x. is formed. Therefore, the thermal print head D1 can suppress the sticking phenomenon similarly to the thermal print heads A1, B1, and C1.

In thermal print head D1, electrode layer 3 has seed layer 303 and plating layer 304 . Since the plated layer 304 is formed by electroplating, it is easier to secure the thickness than in the case of forming by a sputtering method, a CVD method, thick film printing, or the like. That is, the thickness t2 of the electrode layer 3 can be made larger than the thickness t1 of the electrode layer 3 of the thermal print head A1 or the like. Therefore, in the thermal print head D1, even if the surface level difference d1 in the first region 21 of the protective layer 2 is about the thickness t2 of the electrode layer 3, an appropriate gap is secured to suppress the sticking phenomenon. be able to.

[Fifth embodiment]
68 and 69 show the thermal print head E1 according to the fifth embodiment. FIG. 68 is a plan view of essential parts showing the thermal print head E1. FIG. 69 is a cross-sectional view of the essential part along line LXIX-LXIX in FIG.

The thermal print head E1 differs from the thermal print head A1 in the configuration of the glaze layer 14 and the configuration of the protective layer 2 .

The glaze layer 14 of the thermal print head E1 does not include the partial glaze 15 and is composed of the full glaze 16, as shown in FIGS. Alternatively to this example, the glaze layer 14 of the thermal printhead E1 may include a partial glaze 15. FIG. In this case, the partial glaze 15 may be divided into a plurality of separation portions 151 like the thermal print head A1, or may not be divided like the thermal print head B1.

The protective layer 2 of the thermal printhead E1 includes a first layer 201 and a second layer 202, as shown in FIGS. 68 and 69. FIG. The first layer 201 is made of amorphous glass, for example, and the second layer 202 is made of SiC, for example.

Protective layer 2 includes a plurality of depressions 2a. Each of the plurality of depressions 2a is depressed downward in the thickness direction z from the surface of the first layer 201 (the upper surface in the thickness direction z). The depth (dimension in the thickness direction z) of each of the plurality of depressions 2a is not particularly limited, but is, for example, approximately half the thickness of the first layer 201 (dimension in the thickness direction z). Each of the plurality of recesses 2a is formed by laser processing, for example. The plurality of depressions 2a are arranged so that any two depressions 2a adjacent in the main scanning direction x sandwich both of the pair of heat generating portions 41 adjacent in the main scanning direction x with the band-shaped portion 321 of each individual electrode 32 therebetween. are placed in For example, as shown in FIGS. 68 and 69, each of the plurality of depressions 2a overlaps each strip-shaped portion 311 of the common electrode 31 when viewed in the thickness direction z. Unlike this example, the plurality of depressions 2a may be formed so as to overlap the plurality of band-shaped portions 311 and the plurality of band-shaped portions 321, respectively.

In the thermal print head E1, since the first layer 201 is formed with the plurality of depressions 2a, the second layer 202 formed on the first layer 201 enters the plurality of depressions 2a. Therefore, when viewed in the thickness direction z, the second layer 202 is recessed in the thickness direction z in regions overlapping the respective recesses 2a. A plurality of recesses 2a formed in the first layer 201 form a plurality of first recesses 22 on the surface of the protective layer 2 (the upper surface of the second layer 202 in the thickness direction z). Therefore, each of the multiple first recesses 22 overlaps with each of the multiple recesses 2a when viewed in the thickness direction z.

Next, an example of a method for manufacturing the thermal print head E1 will be described below with reference to FIGS. 70 to 72. FIG. FIG. 70 is a flow chart showing an example of a method for manufacturing the thermal print head E1. 71 and 72 are cross-sectional views of essential parts showing one step of the method of manufacturing the thermal print head E1, corresponding to FIG.

As shown in FIG. 70, the method for manufacturing the thermal print head E1 includes a substrate preparation step S51, a glaze forming step S52, an electrode layer forming step S53, a resistor layer forming step S54, a protective layer forming step S55, and a singulation step. It has S561 and assembly step S562.

[Base material preparation step S51]
First, the base material 10 is prepared. The substrate preparation step S51 is performed in the same manner as the substrate preparation steps S11, S21 and S41. Therefore, the base material 10 is a plate material made of ceramic.

[Glaze Forming Step S52]
Next, a glaze layer 14 is formed. In the glaze forming step S52, the glaze is formed by printing a thick film of glass paste on substantially the entire main surface 11 and then firing the glass paste. Thereby, a full-surface glaze 16 is formed. When the glaze layer 14 includes the partial glaze 15, the partial glaze 15 may be formed before or after the formation of the full glaze 16. FIG.

[Electrode layer forming step S53]
Next, the electrode layer 3 is formed. The electrode layer forming step S53 is performed in the same manner as the electrode layer forming steps S13 and S23.

[Resistor layer forming step S54]
Next, a resistor layer 4 is formed. The resistor layer forming step S54 is performed in the same manner as the resistor layer forming steps S14 and S24. The resistor layer 4 to be formed has a strip shape extending in the main scanning direction x when viewed in the thickness direction z, and has a plurality of strip portions 311 and a plurality of strip portions 321 alternately when viewed in the thickness direction z. intersect with

[Protective layer forming step S55]
Next, as shown in FIGS. 71 and 72, protective layer 2 is formed. In the protective layer forming step S55, a first layer forming process S551, a laser machining process S552 and a second layer forming process S553 are performed in this order.

In the first layer forming process S551, as shown in FIG. 71, the first layer 201 is formed on the entire upper surfaces of the glaze layer 14, the electrode layer 3 and the resistor layer 4 after the resistor layer forming step S54. The first layer 201 is made of amorphous glass, for example, and the amorphous glass is made of SiO ₂ , for example. The first layer 201 is formed, for example, by thick-film printing a glass paste and then firing the glass paste. None of the plurality of depressions 2a are formed in the first layer 201 after the first layer forming process S551.

In laser processing S552, a plurality of depressions 2a are formed on the first layer 201 by irradiation with laser light, as shown in FIG. In the laser processing step S552, a laser beam is applied to a region of the first layer 201 that overlaps each band-shaped portion 311 when viewed in the thickness direction z. The plurality of depressions 2a to be formed are depressed downward in the thickness direction z from the upper surface of the first layer 201 in the thickness direction z.

In the second layer forming process S553, the second layer 202 is formed on the first layer 201 after the laser processing S552. The second layer 202 is made of SiC, for example. Formation of the second layer 202 is performed, for example, by a sputtering method or a CVD method. The second layer 202 may be the same amorphous glass layer as the first layer 201 in the thermal print head E1 instead of SiC.

[Singulation step S561] [Assembly step S562]
After that, the thermal print head E1 shown in FIGS. 68 and 69 is manufactured through the singulation process S561 and the assembly process S562. The singulation step S561 is performed in the same manner as the singulation steps S161, S281, S391 and S461, and the assembly step S562 is performed in the same manner as the assembly steps S162, S282, S392 and S462.

The actions and effects of the thermal print head E1 are as follows.

The thermal print head E1, like the thermal print heads A1, B1, C1, and D1, has a plurality of first concave portions 22 alternately arranged along the main scanning direction x in the first region 21 of the protective layer 2. and a plurality of first protrusions 23 are formed. Therefore, the thermal print head E1 can suppress the occurrence of the sticking phenomenon similarly to the thermal print heads A1, B1, C1, and D1.

In the thermal print head E1, the recesses 2a overlap the boundaries of the heat generating portions 41 when viewed in the thickness direction z. According to this configuration, the thickness of the first layer 201 , which is the heat storage layer, becomes thin at the boundaries between the plurality of heat generating portions 41 . This suppresses heat diffusion in the main scanning direction x between the plurality of heat generating portions 41 . Therefore, the thermal print head E1 can improve printing quality and printing efficiency.

In the thermal print head E1, each depth (dimension in the thickness direction z) of each of the plurality of depressions 2a is, for example, approximately half the thickness of the first layer 201 (dimension in the thickness direction z). As a result, the thermal print head E1 can reduce the step d1 between each of the plurality of first concave portions 22 and each of the plurality of first convex portions 23 along the thickness direction z to the thickness of the electrode layer 3 along the thickness direction z. can be greater than t1. Therefore, like the thermal print head A1, the thermal print head E1 can appropriately secure a local gap between the print medium P1 and the protective layer 2 in order to suppress the sticking phenomenon.

FIG. 73 shows a thermal print head E2 according to a modified example (first modified example) of the fifth embodiment and a manufacturing method thereof. FIG. 73 is a cross-sectional view of the main part showing the thermal print head E2 and corresponds to FIG. FIG. 74 is a flow chart showing an example of a method for manufacturing the thermal print head E2.

Unlike the thermal print head E1, the thermal print head E2 has a plurality of depressions 2a formed in the second layer 202. As shown in FIG. As shown in FIG. 73, each of the plurality of recesses 2a is recessed downward in the thickness direction z from the upper surface of the second layer 202 in the thickness direction z. As can be understood from FIG. 73, the plurality of depressions 2a respectively overlaps the belt-shaped portions 311 when viewed in the thickness direction z. In the thermal print head E2, the first recesses 22 are formed by the plurality of recesses 2a formed in the second layer 202. As shown in FIG.

The thermal print head E2 is formed through the steps shown in FIG. 74, for example. As shown in FIG. 74, the method for manufacturing the thermal print head E2 differs from the method for manufacturing the thermal print head E1 (see FIG. 70) in the following points. That is, in the protective layer forming step S55, the first layer forming process S551 and the second layer forming process S553 are performed in order of the laser processing S552.

In the order of steps shown in FIG. 74, since the second layer forming process S553 is performed after the first layer forming process S551, none of the plurality of depressions 2a are formed in the first layer 201. In FIG. Then, since the laser machining process S552 is performed after the second layer forming process S553, a plurality of depressions 2a are formed in the second layer 202. FIG. In the laser processing step S552, a laser beam is applied to a region of the second layer 202 that overlaps with each band-shaped portion 311 when viewed in the thickness direction z.

Each step other than the protective layer forming step S55 is the same as the method for manufacturing the thermal print head E1. Therefore, the thermal print head E2 shown in FIG. 73 is manufactured by making the processing order in the protective layer forming step S55 different from that of the thermal print head E1 described above.

In the thermal print head E2, similarly to the thermal print head E1, the protective layer 2 has first regions 21, and the first regions 21 are a plurality of first concave portions alternately arranged along the main scanning direction x. 22 and a plurality of first protrusions 23 . Therefore, the thermal print head E2 can suppress the occurrence of the sticking phenomenon similarly to the thermal print head E1. Further, in the thermal print head E2, similarly to the thermal print head E1, heat diffusion in the main scanning direction x between the plurality of heat generating portions 41 can be suppressed.

In the thermal print head E2, the plurality of depressions 2a formed in the second layer 202 are arranged in a dot-like polka-dot pattern (for example, matrix or zigzag) when viewed in the thickness direction z, as shown in FIG. may be placed. Although the arrangement of the plurality of depressions 2a is not particularly limited, in order to suppress the diffusion of heat in the main scanning direction x between the plurality of heat generating portions 41, as shown in FIG. The concave portion 22) is preferably formed at a position overlapping each band-shaped portion 311 when viewed in the thickness direction z.

76 to 79 show a thermal print head E3 according to a modified example (second modified example) of the fifth embodiment and a manufacturing method thereof. FIG. 76 is a plan view of the main part showing the thermal print head E3. FIG. 77 is a plan view of the essential part of FIG. 76 with the protective layer 2 omitted. However, in FIG. 77, the first regions 21 (the plurality of first concave portions 22 and the plurality of first convex portions 23) are indicated by imaginary lines. 78 is a cross-sectional view taken along line LXXVIII-LXXVIII in FIG. 76. FIG. FIG. 79 is a flow chart showing an example of a method for manufacturing the thermal print head E3.

Unlike the thermal print heads E1 and E2, the thermal print head E3 does not have a plurality of depressions 2a formed in the protective layer 2, and has a plurality of depressions 141 formed in the glaze layer .

A plurality of depressions 141 are formed in the full glaze 16 of the glaze layer 14 respectively. Note that in an example where the glaze layer 14 includes the partial glaze 15 , the plurality of depressions 141 are formed in the partial glaze 15 . Each of the plurality of recesses 141 is recessed in the thickness direction z from the upper surface of the full glaze 16 in the thickness direction z. As shown in FIG. 77, each of the plurality of depressions 141 is streak-shaped and extends in the sub-scanning direction y when viewed in the thickness direction z. Each of the plurality of depressions 141 is formed in a region that overlaps the first region 21 when viewed in the thickness direction z, and is arranged between the strip-shaped portion 311 and the strip-shaped portion 321 that are adjacent to each other in the main scanning direction x. .

In the thermal print head E3, since the plurality of recesses 141 are formed in the glaze layer 14, the resistor layer 4, the first layer 201, and the second layer 202 formed on the plurality of recesses 141 each have a thickness. It is recessed in the vertical direction z. That is, the plurality of depressions 141 formed in the glaze layer 14 form the plurality of first recesses 22 on the surface of the protective layer 2 (the upper surface of the second layer 202 in the thickness direction z). Therefore, each of the multiple first recesses 22 overlaps with each of the multiple recesses 141 when viewed in the thickness direction z.

The thermal print head E3 is formed through the steps shown in FIG. 79, for example. As shown in FIG. 78, the method of manufacturing the thermal print head E3 differs from the method of manufacturing the thermal print head E1 (see FIG. 70) in the following points. It is that the laser processing step S552 is not performed in the protective layer forming step S55, and the laser processing step S57 is added between the electrode layer forming step S53 and the resistor layer forming step S54.

[Laser processing step S57]
As in the manufacturing method of the thermal print head E1, after the electrode layer forming step S53, a plurality of depressions 141 are formed in the glaze layer 14 (full glaze 16) by laser light irradiation. In the laser processing step S57, the surface of the glaze layer 14 (full-surface glaze 16) is irradiated with a laser beam to exposed portions between the belt-shaped portions 311 and 321 adjacent to each other in the main scanning direction x. . The laser light is emitted along the sub-scanning direction y between each of the band-shaped portions 311 and 321 . A plurality of recesses 141 are formed in the glaze layer 14 by this laser light irradiation.

Next, by performing the resistor layer forming step S54 and the protective layer forming step S55 in this order, irregularities (the plurality of first concave portions 22 and the plurality of first convex portions 23) are formed on the surface of the protective layer 2. FIG. After that, the thermal print head E3 shown in FIGS. 76 to 78 is manufactured through a singulation step S561 and an assembly step S562.

In the thermal print head E3, similarly to the thermal print head E1, the protective layer 2 has first regions 21, and the first regions 21 are a plurality of first concave portions alternately arranged along the main scanning direction x. 22 and a plurality of first protrusions 23 . Therefore, the thermal print head E3 can suppress the occurrence of the sticking phenomenon similarly to the thermal print head E1.

In the thermal print head E3, the depth (dimension in the thickness direction z) of each of the plurality of depressions 141 is not particularly limited, but the thickness of each of the plurality of first recesses 22 and each of the plurality of first protrusions 23 By setting each depth (dimension in the thickness direction z) of the plurality of recesses 141 such that the step d1 along the direction z is larger than the thickness t1 along the thickness direction z of the electrode layer 3, In order to suppress the sticking phenomenon, a local gap between the print medium P1 and the protective layer 2 can be appropriately secured.

In each of the thermal print heads E1 to E3, the electrode layer 3 has a plurality of belt-shaped portions 311 and a plurality of belt-shaped portions 321 alternately arranged in the main scanning direction x. For example, like the thermal print head B1, each band-shaped portion 311 and each band-shaped portion 321 may be arranged at intervals in the sub-scanning direction y. In this case, each recess 2a or each recess 141 is formed between two heat generating portions 41 adjacent to each other in the main scanning direction x when viewed in the thickness direction z.

The thermal printhead, thermal printer, and method of manufacturing the thermal printhead according to the present disclosure are not limited to the above-described embodiments. The specific configuration of each part of the thermal print head and thermal printer of the present disclosure, and the specific processing of the method for manufacturing the thermal print head can be designed and changed in various ways. For example, the thermal printhead, thermal printer, and thermal printhead manufacturing method of the present disclosure include embodiments relating to the following notes.
[Appendix 1]
a substrate having a main surface facing one of the thickness directions;
a resistor layer disposed on the main surface and including a plurality of heat generating portions arranged in the main scanning direction;
an electrode layer disposed on the main surface and forming a conduction path to the plurality of heat generating portions;
a protective layer covering the resistor layer and the electrode layer;
and
The protective layer has a first region that overlaps the plurality of heat generating portions when viewed in the thickness direction and extends in the main scanning direction when viewed in the thickness direction,
The thermal print head, wherein the first region has a plurality of first concave portions and a plurality of first convex portions alternately arranged along the main scanning direction.
[Appendix 2]
the electrode layer includes a plurality of first strips and a plurality of second strips each having a longitudinal direction in the sub-scanning direction;
Each of the plurality of heat-generating portions is connected to each of the plurality of first belt-shaped portions and each of the plurality of second belt-shaped portions, and when viewed in the thickness direction, the plurality of first belt-shaped portions and each of the plurality of second strips, respectively.
[Appendix 3]
further comprising a glaze formed on the main surface,
3. The thermal printhead according to appendix 2, wherein the electrode layer is formed on the glaze.
[Appendix 4]
the glaze includes a partial glaze partially disposed on the major surface;
The partial glaze includes a plurality of separation portions spaced apart from each other,
The plurality of separation units are arranged along the main scanning direction,
3. The thermal printhead according to appendix 3, wherein each of the plurality of first protrusions overlaps each of the plurality of separation portions when viewed in the thickness direction.
[Appendix 5]
The glaze further includes a full glaze,
The partial glaze is formed on the main surface,
5. The thermal printhead according to appendix 4, wherein the full glaze covers the partial glaze and the main surface exposed from the partial glaze.
[Appendix 6]
6. The thermal printhead according to any one of appendices 4 and 5, wherein the resistor layer extends in the main scanning direction and is formed across the plurality of separation portions when viewed in the thickness direction. .
[Appendix 7]
The plurality of first strips and the plurality of second strips are arranged alternately in the main scanning direction,
a portion of each of the plurality of first band-shaped portions overlaps the resistor layer when viewed in the thickness direction;
7. The thermal printhead according to appendix 6, wherein each of the plurality of second band-shaped portions partially overlaps the resistor layer when viewed in the thickness direction.
[Appendix 8]
The resistor layer is formed across each of the plurality of first strip portions and each of the plurality of second strip portions when viewed in the thickness direction,
The protective layer includes a first layer and a second layer laminated in the thickness direction,
The first layer is formed on the resistor layer,
3. The thermal printhead according to appendix 3, wherein the second layer is formed on the first layer.
[Appendix 9]
The resistor layer is divided for each of the plurality of heat generating portions,
Each of the first layer and the second layer is divided into each of the plurality of heat generating portions at a portion overlapping the first region when viewed in the thickness direction, and is formed on each of the plurality of heat generating portions. is placed,
8. The thermal printhead according to appendix 8, wherein each of the plurality of first concave portions overlaps with each of the plurality of heat generating portions when viewed in the sub-scanning direction.
[Appendix 10]
10. The thermal printhead according to appendix 9, wherein each of the plurality of first strips and each of the plurality of second strips are arranged in the sub-scanning direction.
[Appendix 11]
The protective layer further includes a third layer formed on the second layer,
11. The thermal printhead according to Appendix 10, wherein the third layer covers the plurality of heat-generating portions, the first layer, and the second layer.
[Appendix 12]
The protective layer includes a plurality of first depressions overlapping each of the plurality of first depressions when viewed in the thickness direction,
The thermal print according to appendix 8, wherein each of the plurality of first depressions is depressed in the thickness direction from a surface facing the same direction as the main surface in either the first layer or the second layer. head.
[Appendix 13]
The plurality of first strips and the plurality of second strips are arranged alternately in the main scanning direction,
The resistor layer intersects the plurality of first strips and the plurality of second strips when viewed in the thickness direction,
13. The thermal printhead according to Appendix 12, wherein the plurality of first depressions overlap boundaries of the plurality of heat generating portions when viewed in the thickness direction.
[Appendix 14]
The electrode layer further includes a connecting portion connected to each of the plurality of first band-shaped portions,
14. The thermal printhead according to appendix 13, wherein the plurality of first depressions overlap each of the plurality of first strips when viewed in the thickness direction.
[Appendix 15]
13. The thermal printhead according to appendix 12, wherein each of the plurality of first depressions is formed in the second layer and formed in a dot shape when viewed in the thickness direction.
[Appendix 16]
The plurality of first strips and the plurality of second strips are alternately arranged in the main scanning direction,
The glaze is formed with a plurality of second recesses that overlap each of the plurality of first recesses when viewed in the thickness direction and that are recessed from a surface facing the same direction as the main surface in the thickness direction. cage,
3. According to appendix 3, each of the plurality of second recesses extends in the sub-scanning direction and is formed between each of the plurality of first band-shaped portions and each of the plurality of second band-shaped portions. thermal print head.
[Appendix 17]
17. The thermal printhead according to any one of appendices 1 to 16, wherein the substrate is made of ceramic.
[Appendix 18]
3. The thermal printhead of Claim 2, wherein the substrate is composed of a single crystal semiconductor.
[Appendix 19]
Further comprising an insulating layer formed on the main surface,
The resistor layer is formed on the insulating layer while exposing a portion of the insulating layer,
The electrode layer is formed on the resistor layer while exposing the plurality of heat generating portions,
The insulating layer has a second region overlapping the first region when viewed in the thickness direction,
The second region has a plurality of second concave portions and a plurality of second convex portions alternately arranged along the main scanning direction,
19. The thermal printhead according to appendix 18, wherein each of the plurality of first recesses overlaps each of the plurality of second recesses when viewed in the thickness direction.
[Appendix 20]
the base material further has a third projection projecting from the main surface and extending in the main scanning direction;
20. The thermal printhead according to appendix 19, wherein the first area and the second area are located above the third protrusion.
[Appendix 21]
of Supplementary Note 2 to Supplementary Note 20, wherein the step along the thickness direction between each of the plurality of first recesses and each of the plurality of first protrusions is greater than the thickness of the electrode layer along the thickness direction. A thermal printhead according to any one of the preceding claims.
[Appendix 22]
further comprising a glaze formed on the main surface;
the resistor layer is formed on the glaze and extends in the main scanning direction;
each of the plurality of first strips and each of the plurality of second strips are alternately arranged in the main scanning direction and overlap the resistor layer when viewed in the thickness direction;
The thermal printhead according to appendix 2, wherein each of the plurality of first concave portions overlaps with each of the plurality of heat generating portions when viewed in the thickness direction.
[Appendix 23]
23. The thermal printhead of Claim 22, wherein the electrode layer comprises a plated layer made of copper or a copper alloy.
[Appendix 24]
a thermal printhead according to any one of Appendices 1 to 23;
A thermal printer comprising: a platen facing the thermal print head.
[Appendix 25]
preparing a substrate having a main surface facing one of the thickness directions;
forming a resistor layer disposed on the main surface and including a plurality of heat generating portions arranged in the main scanning direction;
a step of forming an electrode layer arranged on the main surface and constituting a conductive path to the plurality of heat generating portions;
forming a protective layer covering the resistor layer and the electrode layer;
and
The protective layer has a first region that overlaps the plurality of heat generating portions when viewed in the thickness direction and extends in the main scanning direction when viewed in the thickness direction,
The method of manufacturing a thermal printhead, wherein the first region has a plurality of first concave portions and a plurality of first convex portions alternately arranged along the main scanning direction.

A1, A2, B1 to B4, C1, D1, E1 to E3: Thermal print head 1: Head substrate 10, 10K: Base material 11, 11K: Main surface 12, 12K: Back surface 13, 13K: Protrusions 130, 130K: Top portions 131A, 131B: First inclined portions 132A, 132B: Second inclined portion 132K: Inclined portion 14: Glaze layer 141: Recess 15: Partial glaze 150: Glass paste 151: Separation portion 16: Full glaze 19: Insulating layer 191: Second region 192 : Second recess 193 : Second protrusion 2 : Protective layer 2a : Recess 201 : First layer 202 : Second layer 203 : Third layer 21 : First region 22 : First recess 23 : First Projection 29 : Groove 3 : Electrode layer 3K : Wiring film 30 : Conductive paste 301 : First conductor layer 301K : First conductor film 302 : Second conductor layer 302K : Second conductor film 303 : Seed layer 304 : Plating layer 31 : Common electrode 311 : Strip portion 312 : Connection portion 312a : Ag layer 313 : Direct portion 314 : Branch portion 315 : Strip portion 316 : Connection portion 32 : Individual electrode 321 : Strip portion 322 : Bonding portion 323 : Connection portion 323a : Parallel portion 323b : Oblique portion 33 : Relay electrode 331 : Strip portion 332 : Connecting portion 4 : Resistor layer 4K : Resistor film 41 : Heat generating portion 5 : Connection substrate 51 : Main surface 52 : Back surface 59 : Connectors 61 and 62 : Wire 7 : Driver IC
78: Protective resin 8: Heat dissipation member 81: Support surface G1: Platen roller Pr: Thermal printer P1: Printing medium

Claims (25)

a substrate having a main surface facing one of the thickness directions;
a resistor layer disposed on the main surface and including a plurality of heat generating portions arranged in the main scanning direction;
an electrode layer disposed on the main surface and forming a conduction path to the plurality of heat generating portions;
a protective layer covering the resistor layer and the electrode layer;
and
The protective layer has a first region that overlaps the plurality of heat generating portions when viewed in the thickness direction and extends in the main scanning direction when viewed in the thickness direction,
The first region has a plurality of first concave portions and a plurality of first convex portions alternately arranged along the main scanning direction,
thermal print head. the electrode layer includes a plurality of first strips and a plurality of second strips each having a longitudinal direction in the sub-scanning direction;
Each of the plurality of heat-generating portions is connected to each of the plurality of first belt-shaped portions and each of the plurality of second belt-shaped portions, and when viewed in the thickness direction, the plurality of first belt-shaped portions is sandwiched between each of the and each of the plurality of second strips,
A thermal printhead according to claim 1 . further comprising a glaze formed on the main surface,
wherein the electrode layer is formed on the glaze;
3. A thermal printhead according to claim 2. the glaze includes a partial glaze partially disposed on the major surface;
The partial glaze includes a plurality of separation portions spaced apart from each other,
The plurality of separation units are arranged along the main scanning direction,
each of the plurality of first protrusions overlaps each of the plurality of separation portions when viewed in the thickness direction;
A thermal printhead according to claim 3. The glaze further includes a full glaze,
The partial glaze is formed on the main surface,
The full glaze covers the partial glaze and the main surface exposed from the partial glaze.
5. A thermal printhead according to claim 4. The resistor layer extends in the main scanning direction and is formed across the plurality of separation portions when viewed in the thickness direction,
6. A thermal printhead according to claim 4 or 5. The plurality of first strips and the plurality of second strips are arranged alternately in the main scanning direction,
a portion of each of the plurality of first band-shaped portions overlaps the resistor layer when viewed in the thickness direction;
A part of each of the plurality of second band-shaped portions overlaps the resistor layer when viewed in the thickness direction,
A thermal printhead according to claim 6 . The resistor layer is formed across each of the plurality of first strip portions and each of the plurality of second strip portions when viewed in the thickness direction,
The protective layer includes a first layer and a second layer laminated in the thickness direction,
The first layer is formed on the resistor layer,
The second layer is formed on the first layer,
A thermal printhead according to claim 3. The resistor layer is divided for each of the plurality of heat generating portions,
Each of the first layer and the second layer is divided into each of the plurality of heat generating portions at a portion overlapping the first region when viewed in the thickness direction, and is formed on each of the plurality of heat generating portions. is placed,
each of the plurality of first concave portions overlaps with each of the plurality of heat generating portions when viewed in the sub-scanning direction;
A thermal printhead according to claim 8 . Each of the plurality of first strips and each of the plurality of second strips are arranged in the sub-scanning direction,
A thermal printhead according to claim 9 . The protective layer further includes a third layer formed on the second layer,
The third layer covers the plurality of heat generating parts, the first layer and the second layer,
A thermal printhead according to claim 10 . The protective layer includes a plurality of first depressions overlapping each of the plurality of first depressions when viewed in the thickness direction,
Each of the plurality of first depressions is depressed in the thickness direction from a surface facing the same direction as the main surface in either the first layer or the second layer.
A thermal printhead according to claim 8 . The plurality of first strips and the plurality of second strips are arranged alternately in the main scanning direction,
The resistor layer intersects the plurality of first strips and the plurality of second strips when viewed in the thickness direction,
The plurality of first depressions overlap boundaries of the plurality of heat generating portions when viewed in the thickness direction.
13. A thermal printhead according to claim 12. The electrode layer further includes a connecting portion connected to each of the plurality of first band-shaped portions,
The plurality of first depressions overlap each of the plurality of first strips when viewed in the thickness direction,
14. The thermal printhead of claim 13. Each of the plurality of first depressions is formed in the second layer and formed in a dot shape when viewed in the thickness direction,
13. A thermal printhead according to claim 12. The plurality of first strips and the plurality of second strips are alternately arranged in the main scanning direction,
The glaze is formed with a plurality of second recesses that overlap each of the plurality of first recesses when viewed in the thickness direction and that are recessed from a surface facing the same direction as the main surface in the thickness direction. cage,
each of the plurality of second recesses extends in the sub-scanning direction and is formed between each of the plurality of first strips and each of the plurality of second strips;
A thermal printhead according to claim 3. The substrate is made of ceramic,
A thermal printhead according to any one of claims 1 to 16. The base material is made of a single crystal semiconductor,
3. A thermal printhead according to claim 2. Further comprising an insulating layer formed on the main surface,
The resistor layer is formed on the insulating layer while exposing a portion of the insulating layer,
The electrode layer is formed on the resistor layer while exposing the plurality of heat generating portions,
The insulating layer has a second region overlapping the first region when viewed in the thickness direction,
The second region has a plurality of second concave portions and a plurality of second convex portions alternately arranged along the main scanning direction,
Each of the plurality of first recesses overlaps each of the plurality of second recesses when viewed in the thickness direction,
19. The thermal printhead of Claim 18. the base material further has a third projection projecting from the main surface and extending in the main scanning direction;
The first region and the second region are located on the third protrusion,
20. The thermal printhead of Claim 19. A step along the thickness direction between each of the plurality of first recesses and each of the plurality of first protrusions is greater than the thickness of the electrode layer along the thickness direction,
A thermal printhead according to any one of claims 2 to 20. further comprising a glaze formed on the main surface;
the resistor layer is formed on the glaze and extends in the main scanning direction;
each of the plurality of first strips and each of the plurality of second strips are alternately arranged in the main scanning direction and overlap the resistor layer when viewed in the thickness direction;
Each of the plurality of first recesses overlaps with each of the plurality of heat generating portions when viewed in the thickness direction,
3. A thermal printhead according to claim 2. The electrode layer includes a plating layer made of copper or a copper alloy,
23. The thermal printhead of Claim 22. a thermal printhead according to any one of claims 1 to 23;
a platen facing the thermal print head;
a thermal printer. preparing a substrate having a main surface facing one of the thickness directions;
forming a resistor layer disposed on the main surface and including a plurality of heat generating portions arranged in the main scanning direction;
a step of forming an electrode layer arranged on the main surface and constituting a conductive path to the plurality of heat generating portions;
forming a protective layer covering the resistor layer and the electrode layer;
and
The protective layer has a first region that overlaps the plurality of heat generating portions when viewed in the thickness direction and extends in the main scanning direction when viewed in the thickness direction,
The first region has a plurality of first concave portions and a plurality of first convex portions alternately arranged along the main scanning direction,
A method for manufacturing a thermal printhead.

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