CN115339245A

CN115339245A - Thermal print head and method of manufacturing thermal print head

Info

Publication number: CN115339245A
Application number: CN202210513591.7A
Authority: CN
Inventors: 仲谷吾郎
Original assignee: Rohm Co Ltd
Current assignee: Rohm Co Ltd
Priority date: 2021-05-14
Filing date: 2022-05-12
Publication date: 2022-11-15
Also published as: JP2022175561A

Abstract

The invention provides a thermal print head and a method for manufacturing the same, which can reduce the cost for manufacturing. A thermal print head (A10) includes: a substrate (10); a wiring layer (20) disposed on the substrate (10); and a resistor layer (30) including a plurality of heat generating sections (31) arranged in the main scanning direction and electrically connected to the wiring layer (20). The wiring layer (20) includes a first layer (20A) in contact with the substrate (10) and a second layer (20B) laminated on the first layer (20A). The first layer (20A) has a composition containing nickel. The composition of the second layer (20B) contains copper. The thickness (t 1) of the first layer (20A) is thinner than the thickness (t 2) of the second layer (20B).

Description

Thermal print head and method of manufacturing thermal print head

Technical Field

The invention relates to a thermal print head and a method of manufacturing the same.

Background

The thermal print head is a main component of a thermal printer that prints on a recording medium such as thermal paper. Patent document 1 discloses an example of a thermal head. The thermal print head comprises a substrate, a common electrode arranged on the substrate, a plurality of individual electrodes arranged on the substrate, and a heating resistor body conducting with the common electrode and the individual electrodes. The heating resistors selectively generate heat by energization through the common electrode and the plurality of individual electrodes, thereby performing dot printing on the recording medium.

The common electrode and the plurality of individual electrodes constituting the thermal head disclosed in patent document 1 are formed by thick-film printing a gold resinate paste and then firing the paste. Therefore, in the thermal print head, the cost taken for the formation of the common electrode and the plurality of individual electrodes is high.

Documents of the prior art

Patent literature

Patent document 1: japanese patent laid-open publication No. 2011-240641.

Disclosure of Invention

Problems to be solved by the invention

In view of the above, an object of the present invention is to provide a thermal print head and a method of manufacturing the same, which can reduce the cost required for manufacturing.

Means for solving the problems

A first aspect of the present invention provides a thermal print head comprising: a substrate; a wiring layer disposed on the substrate; and a resistor layer including a plurality of heat generating portions arranged in a main scanning direction and electrically connected to the wiring layer, wherein the wiring layer includes a first layer in contact with the substrate and a second layer laminated on the first layer, the first layer includes nickel, the second layer includes copper, and the first layer is thinner than the second layer.

A second aspect of the present invention provides a method of manufacturing a thermal print head, including: forming a wiring layer on a base material; and forming a resistor layer including a plurality of heat generating portions arranged in a main scanning direction and electrically connected to the wiring layer, the wiring layer including a first layer formed by electroless plating and a second layer laminated on the first layer, the second layer being formed by electrolytic plating.

Effects of the invention

According to the thermal print head and the manufacturing method thereof of the present invention, cost reduction in manufacturing can be achieved.

Other features and advantages of the present invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying drawings.

Drawings

Fig. 1 is a plan view of a thermal head according to a first embodiment of the present invention.

Fig. 2 is a bottom view of the thermal print head shown in fig. 1.

Fig. 3 is a sectional view taken along the line III-III of fig. 1.

Fig. 4 is an enlarged partial plan view of the thermal print head shown in fig. 1, through a protective layer.

Fig. 5 is a partially enlarged view of fig. 4.

Fig. 6 is a sectional view taken along line VI-VI of fig. 5.

Fig. 7 is a sectional view taken along line VII-VII of fig. 5.

Fig. 8 is a partially enlarged view of fig. 7.

Fig. 9 is a sectional view illustrating a manufacturing process of the thermal head shown in fig. 1.

Fig. 10 is a partially enlarged view of fig. 9.

Fig. 11 is a sectional view illustrating a manufacturing process of the thermal head shown in fig. 1.

Fig. 12 is a partially enlarged view of fig. 11.

Fig. 13 is a sectional view illustrating a manufacturing process of the thermal head shown in fig. 1.

Fig. 14 is a sectional view illustrating a manufacturing process of the thermal head shown in fig. 1.

Fig. 15 is a partially enlarged view of fig. 14.

Fig. 16 is a sectional view illustrating a manufacturing process of the thermal head shown in fig. 1.

Fig. 17 is a sectional view illustrating a manufacturing process of the thermal head shown in fig. 1.

Fig. 18 is a sectional view of a thermal head according to a second embodiment of the present invention.

Fig. 19 is a sectional view of the thermal head shown in fig. 18.

Fig. 20 is a sectional view of a thermal head according to a third embodiment of the present invention.

Fig. 21 is a sectional view of the thermal head shown in fig. 20.

Fig. 22 is a partially enlarged view of fig. 21.

Fig. 23 is a sectional view illustrating a manufacturing process of the thermal head shown in fig. 20.

Fig. 24 is a sectional view illustrating a manufacturing process of the thermal head shown in fig. 20.

Description of the reference numerals

A10, A20, A30: thermal print head

10: substrate

11: base material

111: first side

12: glaze layer

121: second surface

20: wiring layer

20A: first layer

20B: second layer

201: surface of

201A: concave part

21: public wiring

211: a first belt part

211A: base part

211B: extension part

212: connecting part

22: single wire harness

221: second band-shaped part

221A: base part

221B: extension part

222: intermediate section

222A: parallel portion

222B: diagonal part

223: connecting part

223A: first connecting part

223B: second connecting part

30: resistor layer

31: heating part

40: protective layer

50: electric wire

71: driver IC

72: sealing resin

73: connector with a locking member

74: heat radiator

81: recording medium

82: embossing roller

Δ L: deviation of

t1, t2: and (4) thickness.

Detailed Description

A mode for carrying out the present invention will be described based on the drawings.

[ first embodiment ]

A thermal head a10 according to a first embodiment of the present invention will be described with reference to fig. 1 to 8. The thermal head a10 includes a substrate 10, a wiring layer 20, a resistor layer 30, and a protective layer 40. The thermal head a10 further includes a drive IC71, a sealing resin 72, a connector 73, and a heat dissipation member 74. In fig. 4 and 5, the protective layer 40 is illustrated for the sake of convenience.

The thermal head a10 shown in these figures is an electronic device that selectively generates heat in a plurality of heat generating portions 31 (details will be described later) included in the resistor layer 30, and thereby performs printing on a recording medium 81 such as thermal paper as shown in fig. 3. The resistor layer 30 is formed by printing and firing. Therefore, the thermal head a10 is referred to as a so-called thick film type.

Here, for convenience of explanation, the main scanning direction of the thermal head a10 is referred to as "x direction". The sub-scanning direction of the thermal head a10 is referred to as "y direction". The thickness direction of the substrate 10 is referred to as "z direction". The z-direction is orthogonal to both the x-direction and the y-direction. In the following description, "viewed in the z direction" refers to a plan view.

As shown in fig. 1 and 2, the substrate 10 has a strip shape extending in the x direction. As shown in fig. 6 and 7, in the thermal head a10, the substrate 10 includes a base material 11 and a glaze layer 12. The composition of the substrate 11 contains alumina (Al) ₂ O ₃ ). The substrate 11 is a ceramic made of a material containing alumina, a resin binder, and the like. The material of the substrate 10 may contain a light-shielding material in addition to these materials. The light-shielding material is, for example, carbon (C).

As shown in fig. 6 and 7, the glaze layer 12 is laminated on the substrate 11. The glaze layer 12 is made of a material containing amorphous glass. The amorphous glass is, for example, siO ₂ －BaO－Al ₂ O ₃ -SnO-ZnO glasses. Thus, glaze layer 12 appears transparent or white.

As shown in fig. 6 and 7, the substrate 11 has a first surface 111. First surface 111 is opposite glaze layer 12. Glaze layer 12 covers the entirety of first surface 111. Glaze layer 12 has second surface 121 facing the same side as first surface 111 in the z direction. The surface roughness of the second face 121 is smaller than the surface roughness of the first face 111.

As shown in fig. 1 and 4, the wiring layer 20 is disposed on the substrate 10. The wiring layer 20 constitutes a conductive path for passing electricity to the resistor layer 30. The wiring layer 20 includes a common wiring 21 and a plurality of individual wirings 22. In the thermal head a10, a current flows from the common wiring 21 to the plurality of individual wirings 22 through the resistor layer 30. Therefore, the common wiring 21 is a positive electrode, and the plurality of individual wirings 22 are negative electrodes.

As shown in fig. 6 and 7, the wiring layer 20 includes a first layer 20A and a second layer 20B. The first layer 20A is in contact with the substrate 10. In the thermal head a10, the first layer 20A is in contact with the second surface 121 of the glaze layer 12. The composition of the first layer 20A contains nickel (Ni). The second layer 20B is laminated on the first layer 20A. The composition of the second layer 20B contains copper (Cu). As shown in fig. 8, the thickness t1 of the first layer 20A is thinner than the thickness t2 of the second layer 20B.

As shown in fig. 8, the wiring layer 20 has a surface 201. The surface 201 faces the same side in the z-direction as the first face 111 of the substrate 11. The surface 201 is comprised by the second layer 20B. A plurality of concave portions 201A recessed toward the first layer 20A are formed on the surface 201. The surface 201 has a surface roughness less than the surface roughness of the first face 111.

As shown in fig. 4 and 5, the common line 21 includes a connection portion 212 and a plurality of first strip portions 211. The connection portion 212 is provided separately from the resistor layer 30 in the y direction, and is in a strip shape extending in the x direction.

As shown in fig. 4 and 5, the plurality of first strip-shaped portions 211 extend from the connection portion 212 toward the resistor layer 30. The plurality of first strip portions 211 are arranged at equal intervals in the x direction. The first band portions 211 have a base portion 211A and an extending portion 211B. The base 211A is rectangular in shape. One side of the base portion 211A in the y direction is connected to the connection portion 212. The extending portion 211B extends from the other side of the base portion 211A in the y direction toward the resistor layer 30. The width (dimension in the x direction) of the extension portion 211B is smaller than the width (dimension in the x direction) of the base portion 211A. The width of the extension portion 211B is set to 25 μm or less.

As shown in fig. 4 and 5, the individual wires 22 extend in the y direction. The individual wires 22 are arranged on the substrate 10 as bundles corresponding to the respective driver ICs 71. The plurality of individual wires 22 apply voltages to individually selected portions of the resistor layer 30. The individual wires 22 are arranged in the x direction. The individual wires 22 include a second strip portion 221, an intermediate portion 222, and a connecting portion 223.

As shown in fig. 4 and 5, the second strip-shaped portion 221 has a strip shape extending in the y direction. The second strip portion 221 is located between two first strip portions 211 adjacent in the x direction among the plurality of common wirings 21 of the common wirings 21. The second strip portion 221 has a base portion 221A and an extension portion 221B. The base 221A is rectangular in shape. One side of the base portion 221A in the y direction is connected to the intermediate portion 222. The extending portion 221B extends from the other side of the base portion 221A in the y direction toward the resistor layer 30. The width (dimension in the x direction) of the extension portion 221B is smaller than the width (dimension in the x direction) of the base portion 221A. The width of the extension portion 221B is set to 25 μm or less.

As shown in fig. 4 and 5, the intermediate portion 222 connects the second band-shaped portion 221 and the connection portion 223. The intermediate portion 222 has a parallel portion 222A and a diagonal portion 222B. The parallel portion 222A is connected to the connection portion 223 on one side in the y direction and along the y direction. The width (dimension in the x direction) of the parallel portion 222A is set to 20 μm or less. The diagonal portion 222B is inclined with respect to the y direction. The diagonal portion 222B is connected to the base portion 221A of the second strip portion 221 on one side in the y direction, and is connected to the parallel portion 222A on the other side in the y direction. As shown in fig. 4, when the boundary positions of the parallel portion 222A and the oblique portion 222B in the plurality of individual wires 22 arranged as bundles corresponding to the respective driver ICs 71 are compared at both ends in the x direction, a deviation Δ L in the y direction occurs.

As shown in fig. 4, the connecting portion 223 is located on the opposite side of the second strip portion 221 with respect to the intermediate portion 222 in the y direction. The connecting portion 223 is connected to the parallel portion 222A of the intermediate portion 222. The connection portion 223 includes a first connection portion 223A and a second connection portion 223B. The second connection portion 223B is provided apart from the first connection portion 223A in the y direction. Thus, the first connection portions 223A of the plurality of individual wires 22 and the second connection portions 223B of the plurality of individual wires 22 are arranged alternately in the x direction. The width (dimension in the x direction) of the parallel portion 222A connected to the second connection portion 223B and located between two adjacent first connection portions 223A is set to 10 μm or less. The plurality of wires 50 are individually connected to the connection portions 223 of the plurality of individual wires 22. The composition of the plurality of wires 50 contains, for example, gold (Au).

As shown in fig. 1 and 4, the resistor layer 30 is a strip-like shape extending in the x direction. The resistor layer 30 is in contact with the substrate 10. In the thermal head a10, the resistor layer 30 is in contact with the second surface 121 of the glaze layer 12. The resistor layer 30 intersects the plurality of first strip portions 211 of the common line 21 and the second strip portions 221 of the plurality of individual lines 22. The resistor layer 30 covers each of the plurality of first strip portions 211 and the second strip portions 221 of the plurality of individual wires 22. A region of the resistor layer 30 sandwiched by a portion covering any of the plurality of first strip-shaped portions 211 and a portion covering any of the second strip-shaped portions 221 of the plurality of individual wires 22 located next to the first strip-shaped portions 211 in the x direction is a heat generating portion 31. Thus, the resistor layer 30 includes a plurality of heat generating portions 31 arranged in the x direction and electrically connected to the wiring layer 20. By selectively applying current through the wiring layer 20, the plurality of heat generating portions 31 selectively generate heat. Thereby, dot printing is performed on the recording medium 81 shown in fig. 3. The material of the resistor layer 30 can be selected to have a higher resistivity than the wiring layer 20. An example of the material of the resistor layer 30 includes ruthenium oxide (RuO) ₂ ) Conductive paste of particles and glass powder. The maximum thickness of the resistor layer 30 is 6 μm to 10 μm.

As shown in fig. 6 and 7, in the thermal head a10, the resistor layer 30 is in contact with the second layer 20B of the wiring layer 20. Therefore, the resistor layer 30 crosses the plurality of first strip portions 211 of the common line 21 and the second strip portions 221 of the plurality of individual lines 22. As shown in fig. 8, the resistor layer 30 is in contact with a plurality of recesses 201A formed in the surface 201 of the second layer 20B.

As shown in fig. 6 and 7, the protective layer 40 is in contact with the substrate 10. In the thermal head a10, the protective layer 40 is in contact with the second surface 121 of the glaze layer 12. The protective layer 40 covers the resistor layer 30. In addition, the protective layer 40 covers the wiring layer 20 in addition to a part of the plurality of individual wires 22 including the connection portion 223. The protective layer 40 is made of a material containing amorphous glass, as in the case of the glaze layer 12.

As shown in fig. 1 and 3, the driver IC71 is located on the other side in the y direction with respect to the resistor layer 30. The driver IC71 is mounted on the substrate 10. A plurality of pads (not shown) are provided on the upper surface of the driver IC 71. A plurality of wires 50 connected to the connection portions 223 of the individual wires 22 corresponding to the driver ICs 71 are connected to several of the plurality of pads. Thereby, the driver IC71 is electrically connected to the plurality of individual wires 22 corresponding thereto. A plurality of wires 50 connected to the wiring disposed on the substrate 10 are connected to the other plurality of pads. The drive IC71 selectively energizes the individual wires 22 via the electric wires 50. Thereby, the plurality of heat generating portions 31 included in the resistor layer 30 selectively generate heat. The drive IC71 may be mounted on a wiring board supported by the heat dissipation member 74, separated from the substrate 10 in the y direction. The wiring board is, for example, a flexible board.

As shown in fig. 3, the sealing resin 72 covers the driver IC71 and the plurality of wires 50. Further, the sealing resin 72 also covers a part of the regions (the plurality of connection portions 223 and the like) of the plurality of individual wires 22 not covered with the protective layer 40. The sealing resin 72 is, for example, a black and soft resin for underfill.

As shown in fig. 1 to 3, the connector 73 is disposed at an end portion of the substrate 10 located on the opposite side of the resistor layer 30 with respect to the driver IC71 in the y direction. The connector 73 is used to connect the thermal head a10 to a thermal printer. The connector 73 is connected to wiring disposed on the substrate 10. Thereby, the connector 73 is electrically connected to the individual wires 22 via the wires, the driver IC71, and the wires 50. The connector 73 is electrically connected to the connection portion 212 of the common wiring 21 via the wiring.

As shown in fig. 3, the heat dissipation member 74 is located on the opposite side of the resistor layer 30 from the substrate 10 in the z direction. The substrate 10 is bonded to the heat dissipation member 74 via a bonding material (not shown). The heat dissipation member 74 is composed of, for example, aluminum (Al).

Next, the operation of the thermal head a10 will be described.

As shown in fig. 3, the plurality of heat generating portions 31 of the thermal head a10 face a platen roller 82 incorporated in the thermal printer via the protective layer 40. The recording medium 81 is inserted between the region of the protective layer 40 covering the plurality of heat generating portions 31 and the platen roller 82. When the thermal printer operates, the platen roller 82 rotates to convey the recording medium 81 at a constant speed. At this time, when the plurality of heat generating portions 31 selectively generate heat, the heat is transferred to the recording medium 81 through the protective layer 40, and thereby printing is performed on the recording medium 81. At the same time, heat generated from the plurality of heat generating portions 31 is also transferred to the glaze layer 12. A portion of this heat is stored in the glaze layer 12. The heat is released to the outside of the thermal head a10 through the substrate 11 and the heat-radiating member 74.

Next, an example of a method for manufacturing the thermal head a10 will be described with reference to fig. 9 to 17.

First, as shown in fig. 9, a glaze layer 12 is formed on a substrate 11. The glaze layer 12 is formed by thick-printing an amorphous glass paste and then firing the paste. Thereby, the first surface 111 of the substrate 11 is covered with the glaze layer 12. Then, after firing the paste, the surface of the glaze layer 12 is roughened as shown in fig. 10. The surface of the glaze layer 12 is roughened by a spray treatment. The method of the spray treatment is, for example, wet (wet) spraying. Wet blasting is a method of mixing an abrasive and water to perform blasting treatment. The abrasive material is, for example, silica sand. Through this step, the second surface 121 appears on the surface of the glaze layer 12.

Next, as shown in fig. 11 to 15, a wiring layer 20 is formed on the base material 11. In the method of manufacturing the thermal head a10, the wiring layer 20 is formed by being in contact with the second surface 121 of the glaze layer 12.

First, as shown in fig. 11 and 12, the first layer 20A is formed in contact with the second surface 121 of the glaze layer 12. The first layer 20A is formed by depositing a metal layer on the second surface 121 by electroless plating. The composition of the metal layer contains nickel. Thereby, the entirety of the second face 121 is covered with the first layer 20A.

Next, as shown in fig. 13, a second layer 20B laminated on the first layer 20A is formed. The second layer 20B is formed by electrolytic plating using the first layer 20A as a conductive path after the first layer 20A is subjected to photolithographic patterning. Thereby, a metal layer is deposited on the first layer 20A. The composition of the metal layer contains copper.

Next, as shown in fig. 14, the first layer 20A exposed from the second layer 20B is removed. The removal of the first layer 20A is performed by the same blasting as the roughening of the surface of the glaze layer 12 shown in fig. 10. The spraying treatment method is the above wet spraying. Through this step, the formation of the wiring layer 20 is completed. Through this step, as shown in fig. 15, the surface 201 on which the plurality of concave portions 201A are formed appears on the second layer 20B. This is because the abrasive involved in the blasting process also collides with the second layer 20B when the first layer 20A is removed.

Next, as shown in fig. 16, a resistor layer 30 including a plurality of heat generating portions 31 electrically connected to the wiring layer 20 is formed. In forming the resistor layer 30, first, a paste containing a metal element is thick-film printed in a strip shape extending in the x direction. The paste comprises ruthenium oxide particles and glass frit. The paste is provided in contact with the second layer 20B of the wiring layer 20. Then, the paste is fired. Finally, the fired paste is trimmed as appropriate to adjust the resistance value, thereby forming the resistor layer 30.

Next, as shown in fig. 17, a protective layer 40 is formed in contact with the glaze layer 12 so as to cover the resistor layer 30 and a part of the wiring layer 20. The protective layer 40 is formed by thick-film printing an amorphous glass paste and then firing the paste.

After the protective layer 40 is formed, the driver IC71 is mounted on the second surface 121 of the glaze layer 12 by die bonding. Next, the plurality of electric wires 50 are formed by wire bonding, and then, the sealing resin 72 is formed. Subsequently, the substrate 10 is cut along the y direction. Finally, the connector 73 and the heat dissipation member 74 are attached to the substrate 10, thereby obtaining the thermal head a10.

Next, the operation and effect of the thermal head a10 will be described.

The wiring layer 20 of the thermal head a10 includes a first layer 20A in contact with the substrate 10 and a second layer 20B laminated on the first layer 20A. The first layer 20A contains nickel in composition. The composition of the second layer 20B contains copper. The thickness of the first layer 20A is thinner than the thickness of the second layer 20B. This can reduce the cost required for forming the wiring layer 20 per unit volume, as compared with the wiring layer 20 formed from gold-containing resinate paste. Therefore, according to the thermal head a10, reduction in cost taken for manufacturing the thermal head a10 can be achieved.

According to the manufacturing method of the thermal head a10, the first layer 20A of the wiring layer 20 is formed by electroless plating. Thereby, the second layer 20B of the wiring layer 20 can be formed by electrolytic plating. The thickness of the second layer 20B can be freely set. For example, by further increasing the thickness of the second layer 20B, the resistance of the wiring layer 20 can be reduced. This can suppress power loss in the thermal head a10.

The step of forming the glaze layer 12 in the process of manufacturing the thermal head a10 includes a step of roughening the surface of the glaze layer 12. This can prevent the first layer 20A of the wiring layer 20 from being reduced in adhesion to the substrate 10. The step of forming the wiring layer 20 in the manufacturing process of the thermal head a10 includes a step of removing the first layer 20A exposed from the second layer 20B. The spray treatment is used in the step of removing the first layer 20A and the step of roughening the surface of the glaze layer 12. This can shorten the time required for these steps compared to etching treatment.

Glaze layer 12 of substrate 10 has a function of storing part of heat emitted from plurality of heat generating portions 31 of resistor layer 30. For example, when the thermal head a10 is used in a cold region, a rapid temperature decrease in the plurality of resistor layers 30 can be suppressed by the heat storage function of the glaze layer 12. This prevents deterioration in the print quality on the recording medium 81. In this structure, the glaze layer 12 preferably covers the entire first surface 111 of the substrate 11.

In the thermal head a10, the resistor layer 30 is in contact with the second layer 20B of the wiring layer 20. As shown in fig. 8, the resistor layer 30 is in contact with the plurality of recesses 201A of the second layer 20B. This can improve the adhesion of the resistor layer 30 to the wiring layer 20. Further, since the surface area of the wiring layer 20 in contact with the resistor layer 30 is enlarged, the resistance at the interface between the wiring layer 20 and the resistor layer 30 can be reduced.

[ second embodiment ]

A thermal head a20 according to a second embodiment of the present invention will be described with reference to fig. 18 and 19. In these drawings, the same or similar elements as those of the thermal head a10 are denoted by the same reference numerals, and redundant description thereof is omitted.

In the thermal head a20, the structure of the wiring layer 20 and the resistor layer 30 is different from that of the thermal head a10 described above.

As shown in fig. 18 and 19, in the thermal head a20, the resistor layer 30 is in contact with the first layer 20A of the wiring layer 20. Therefore, the resistor layer 30 is buried under the plurality of first strip portions 211 of the common line 21 and the plurality of second strip portions 221 of the individual lines 22. Therefore, the resistor layer 30 does not contact the plurality of recesses 201A of the second layer 20B of the wiring layer 20 shown in fig. 8. The thermal head a20 is obtained by providing a step of shaping the resistor layer 30 shown in fig. 16 before the step of forming the wiring layer 20 shown in fig. 11 to 15.

Next, the operation and effect of the thermal head a20 will be described.

The wiring layer 20 of the thermal head a20 includes a first layer 20A in contact with the substrate 10 and a second layer 20B laminated on the first layer 20A. The first layer 20A contains nickel in composition. The composition of the second layer 20B contains copper. The thickness of the first layer 20A is thinner than the thickness of the second layer 20B. Therefore, with the thermal head a20, it is also possible to achieve a reduction in the cost spent for manufacturing the thermal head a 20. Further, the thermal head a20 has a structure common to the thermal head a10, and thus can achieve the same operational effects as the thermal head a10.

[ third embodiment ]

A thermal head a30 according to a third embodiment of the present invention will be described with reference to fig. 20 to 22. In these drawings, the same or similar elements as those of the thermal head a10 are denoted by the same reference numerals, and redundant description thereof is omitted.

In the thermal head a30, the structure of the substrate 10 is different from that of the thermal head a10 described above.

As shown in fig. 20 and 21, in the thermal head a30, the substrate 10 includes the base material 11 but does not include the glaze layer 12. Thereby, as shown in fig. 22, the first layer 20A of the wiring layer 20 is in contact with the first surface 111 of the base material 11. Further, the resistor layer 30 is in contact with the first surface 111 of the substrate 11.

Next, as shown in fig. 23 and 24, an example of a method for manufacturing the thermal head a30 will be described.

In manufacturing the thermal head a30, the step of forming the glaze layer 12 shown in fig. 9 and 10 is not required. Therefore, in the step of forming the wiring layer 20, as shown in fig. 23, the first layer 20A is formed so as to cover the entire first surface 111 of the base material 11. Since the surface roughness of the first surface 111 of the substrate 11 is larger than the surface roughness of the second surface 121 of the glaze layer 12, the step of roughening the surface (first surface 111) of the substrate 11 is not necessary, as in fig. 10.

After the steps shown in fig. 23, the second layer 20B of the wiring layer 20 is formed by the same method as the steps shown in fig. 13. Then, as shown in fig. 24, the first layer 20A exposed from the second layer 20B is removed. The method of removing the first layer 20A is the same as the method of removing the first layer 20A in manufacturing the thermal head a10. As shown in fig. 24, when the first layer 20A is removed, the first surface 111 of the base material 11 is exposed.

Then, the thermal head a30 is obtained through the step of forming the resistor layer 30 shown in fig. 16 and the step of forming the protective layer 40 shown in fig. 17.

Next, the operation and effect of the thermal head a30 will be described.

The wiring layer 20 of the thermal head a30 includes a first layer 20A in contact with the substrate 10 and a second layer 20B laminated on the first layer 20A. The first layer 20A contains nickel in composition. The composition of the second layer 20B contains copper. The thickness of the first layer 20A is thinner than the thickness of the second layer 20B. Therefore, with the thermal head a30, it is also possible to achieve a reduction in the cost spent for manufacturing the thermal head a 20. Further, the thermal head a30 has a structure common to the thermal head a10, and thus can achieve the same operational effects as the thermal head a10.

The substrate 10 of the thermal head a30 does not include the glaze layer 12. Therefore, the heat transfer path from the plurality of heat generating portions 31 of the resistor layer 30 to the substrate 11 can be shortened, and the heat dissipation performance of the thermal head a30 can be further improved. In addition, in manufacturing the thermal head a30, the step of forming the glaze layer 12 is not required. Therefore, the manufacturing efficiency of the thermal head a30 can be improved.

The present invention is not limited to the above-described embodiments. The specific structure of each part of the present invention can be changed in various ways.

Hereinafter, a technical structure of the thermal head and the method of manufacturing the same according to the present invention will be described.

[ Note 1]

A thermal print head, comprising:

a substrate; a wiring layer disposed on the substrate; and

a resistor layer including a plurality of heat generating portions arranged in a main scanning direction and electrically connected to the wiring layer,

the wiring layer includes a first layer in contact with the substrate and a second layer laminated on the first layer,

the first layer has a composition comprising nickel,

the composition of the second layer contains copper,

the first layer has a thickness thinner than a thickness of the second layer.

[ Note 2]

The thermal head according to supplementary note 1, wherein,

the substrate comprises a base material and a glaze layer laminated on the base material,

the first layer is in contact with the glaze layer.

[ Note 3]

The thermal head according to supplementary note 2, wherein,

the substrate has a first side opposite the glaze layer,

the glaze layer has a second surface facing the same side as the first surface in a thickness direction of the substrate,

the first layer is in contact with the second face,

the second face has a surface roughness less than a surface roughness of the first face.

[ Note 4]

The thermal head according to supplementary note 3, wherein,

the glaze layer covers the entirety of the first surface.

[ Note 5]

The thermal head according to supplementary note 1, wherein,

the substrate comprises a base material and a plurality of first and second substrates,

the first layer is in contact with the substrate.

[ Note 6]

The thermal print head according to any one of supplementary notes 2 to 5, wherein,

the composition of the base material contains alumina.

[ Note 7]

The thermal print head according to any one of supplementary notes 1 to 6, wherein,

the resistor layer is in contact with the second layer.

[ Note 8]

the resistor layer is in contact with the first layer.

[ Note 9]

The thermal print head according to any one of supplementary notes 1 to 8, wherein,

the wiring layer includes a common wiring and a plurality of individual wirings,

the common wiring has: a connection portion provided separately from the resistor layer in a sub-scanning direction and extending in the main scanning direction; and a plurality of first strip-shaped portions extending from the connection portion toward the resistor layer,

the plurality of individual wires have second strip-shaped portions extending in the sub-scanning direction,

the second belt-shaped portion is located between two adjacent ones of the plurality of first belt-shaped portions in the main scanning direction.

[ Note 10]

The thermal head according to supplementary note 9, wherein,

the resistor layer intersects the plurality of first strip portions and the second strip portions.

[ Note 11]

The thermal print head according to any one of supplementary notes 1 to 10, wherein,

further comprising a protective layer in contact with the substrate and covering the resistor layer.

[ Note 12]

The thermal print head according to any one of supplementary notes 1 to 11, wherein,

further comprising a heat dissipation member located on the opposite side of the substrate from the resistor layer in the thickness direction of the substrate,

the substrate is joined to the heat dissipation member.

[ Note 13]

A method of manufacturing a thermal print head, comprising:

forming a wiring layer on a base material; and

a step of forming a resistor layer including a plurality of heat generating portions arranged in a main scanning direction and electrically connected to the wiring layer,

the wiring layer includes a first layer and a second layer laminated on the first layer,

the first layer is formed by electroless plating,

the second layer is formed by electrolytic plating.

[ Note 14]

The method of manufacturing a thermal head according to supplementary note 13, wherein,

the step of forming the wiring layer includes a step of forming the second layer and then removing the first layer exposed from the second layer.

[ Note 15]

The method of manufacturing a thermal head according to supplementary note 14, wherein,

further comprising a step of forming a glaze layer on the base material before the step of forming the wiring layer,

the step of forming the glaze layer includes a step of roughening the surface of the glaze layer.

[ Note 16]

The method of manufacturing a thermal head according to supplementary note 15, wherein,

the step of removing the first layer and the step of roughening the surface of the glaze layer are performed by a spray treatment.

[ Note 17]

The method of manufacturing a thermal head according to any one of supplementary notes 13 to 16, wherein,

in the step of forming the resistor layer, the resistor layer is formed by printing a paste containing a metal element and then firing the paste.

Claims

1. A thermal print head, comprising:

a substrate;

a wiring layer disposed on the substrate; and

the first layer has a composition comprising nickel,

the composition of the second layer contains copper,

the first layer has a thickness thinner than a thickness of the second layer.

2. The thermal print head of claim 1, wherein:

the first layer is in contact with the glaze layer.

3. The thermal print head of claim 2, wherein:

the substrate has a first face opposite the glaze layer,

the first layer is in contact with the second face,

4. A thermal print head according to claim 3, wherein:

the glaze layer covers the entirety of the first surface.

5. The thermal print head of claim 1, wherein:

the substrate comprises a base material and a plurality of metal layers,

the first layer is in contact with the substrate.

6. The thermal print head according to any one of claims 2 to 5, wherein:

the composition of the base material contains alumina.

7. The thermal print head according to any one of claims 1 to 6, wherein:

the resistor layer is in contact with the second layer.

8. The thermal print head according to any one of claims 1 to 6, wherein:

the resistor layer is in contact with the first layer.

9. The thermal print head according to any one of claims 1 to 8, wherein:

10. The thermal print head of claim 9, wherein:

11. The thermal print head according to any one of claims 1 to 10, wherein:

12. The thermal print head according to any one of claims 1 to 11, wherein:

the substrate is joined to the heat dissipation member.

13. A method of manufacturing a thermal print head, comprising:

forming a wiring layer on a base material; and

the first layer is formed by electroless plating,

the second layer is formed by electrolytic plating.

14. The method of manufacturing a thermal print head according to claim 13, wherein:

15. The method of manufacturing a thermal print head according to claim 14, wherein:

16. A method of manufacturing a thermal print head according to claim 15, wherein:

17. The method of manufacturing a thermal print head according to any one of claims 13 to 16, wherein: