阅读说明：本技术 热敏打印头
(Thermal print head
) 是由 楠本雄司
有泷康之
吉田裕哉
一色翔太 于 2020-02-27 设计创作，主要内容包括：本发明提供一种热敏打印头,其可以避免通过凹版胶印印刷形成的多个配线的质量下降,具备：基板(10),其具有朝向z方向的主面(10A)；多个配线(30),它们配置于主面(10A)上；电阻体,其沿x方向排列且包含与多个配线(30)导通的多个发热部,多个配线(30)中的至少任一个具有与x方向交叉的多个缘(301)和沿z方向贯通的多个空隙部(302),多个空隙部(302)均位于多个缘(301)中相邻的两个缘(301A、301B)之间。(The present invention provides a thermal print head which can avoid the quality reduction of a plurality of wirings formed by gravure offset printing, and the thermal print head comprises: a substrate (10) having a main surface (10A) facing in the z-direction; a plurality of wires (30) arranged on the main surface (10A); and a resistor body which is arranged in the x direction and includes a plurality of heat generating portions which are electrically connected to the plurality of wires (30), wherein at least one of the plurality of wires (30) has a plurality of edges (301) which intersect the x direction and a plurality of void portions (302) which penetrate in the z direction, and each of the plurality of void portions (302) is located between two adjacent edges (301A, 301B) of the plurality of edges (301).)
1. A thermal print head is provided with:
a substrate having a main surface facing in a thickness direction;
a plurality of wires arranged on the main surface; and
a resistor body arranged in the main scanning direction and including a plurality of heat generating portions electrically connected to the plurality of wires,
at least one of the plurality of wirings has a plurality of edges intersecting the main scanning direction and a plurality of void portions penetrating in the thickness direction,
the plurality of voids are each located between adjacent ones of the plurality of rims.
2. A thermal print head according to claim 1,
any of the plurality of wirings forms a first pattern in which the plurality of edges are inner edges of the wirings and the plurality of void portions are all holes,
the first pattern is a mesh shape as viewed in the thickness direction.
3. A thermal print head according to claim 2,
in the wiring forming the first pattern, the plurality of void portions are staggered.
4. The thermal print head according to claim 2 or 3,
any of the plurality of wirings is formed in a second pattern in which the plurality of edges are outer edges of the wirings and the plurality of void portions are each a notch recessed in a direction orthogonal to a direction in which the wirings extend,
in the wiring forming the second pattern, the plurality of void portions are located on both sides in a direction orthogonal to a direction in which the wiring extends.
5. A thermal print head according to claim 4,
the wiring forming the second pattern extends in the main scanning direction.
6. A thermal print head according to claim 5,
in the wiring forming the second pattern, the plurality of void portions are staggered in the main scanning direction.
7. A thermal print head according to claim 6,
in the wiring forming the second pattern, the plurality of void portions are each triangular in shape as viewed in the thickness direction.
8. The thermal print head according to any one of claims 4 to 7, wherein the plurality of wirings are composed of a material containing gold, silver, or copper.
9. A thermal print head according to any one of claims 4 to 8,
the plurality of wirings include a common wiring,
the common wiring includes a connecting portion separated from the resistor in a sub-scanning direction and extending in the main scanning direction, and a plurality of first strip-shaped portions extending from the connecting portion toward the resistor,
the coupling portion forms the first pattern.
10. A thermal print head according to claim 9,
the common wire has a grounding portion extending from either one of both ends of the connecting portion in the main scanning direction to a side of the connecting portion in the sub scanning direction where the resistor is located,
the ground portion forms the first pattern.
11. A thermal print head according to claim 10,
the common wiring has a thin metal layer, and the thin metal layer is disposed on the connection portion in a contact manner and extends in the main scanning direction.
12. The thermal print head according to claim 10 or 11,
the plurality of wires further comprises a plurality of individual wires,
each of the plurality of individual wires has a second strip-shaped portion extending from a side opposite to the connecting portion with respect to the resistor in the sub-scanning direction toward the resistor,
the second belt-shaped portion is located between the plurality of first belt-shaped portions adjacent to each other in the main scanning direction.
13. A thermal print head according to claim 12,
the resistor intersects both the plurality of first strip-shaped portions and the second strip-shaped portions of the plurality of individual wires.
14. A thermal print head according to claim 13,
further comprising a driver IC positioned on the opposite side of the resistor body with respect to the plurality of individual wires in the sub-scanning direction,
the plurality of independent wirings are all conducted with the drive IC.
15. A thermal print head according to claim 14,
at least one of the plurality of wires located on the opposite side of the resistor body from the plurality of individual wires in the sub-scanning direction and electrically connected to the driver IC extends in the main scanning direction, and the second pattern is formed.
16. The thermal print head according to any one of claims 12 to 15,
further comprising a glaze layer laminated on the main surface,
the plurality of wires are connected and arranged on the glaze layer.
17. A thermal print head according to claim 16,
the plurality of first strip-shaped portions and the plurality of second strip-shaped portions of the individual wires each include a section sandwiched between the glaze layer and the resistor.
Technical Field
The present invention relates to a thermal print head in which a plurality of wirings are formed by gravure offset printing.
Background
The thermal 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 conventional thermal print head. The thermal print head disclosed in the same document includes an insulating substrate, a plurality of wires (comb-shaped electrodes and individual electrodes in patent document 1) disposed on the insulating substrate, and a heating resistor electrically connected to the plurality of wires. As the plurality of wires are energized, the plurality of heat generating portions constituting the heat generating resistor selectively generate heat, thereby performing dot printing on the recording medium.
The plurality of wirings of the thermal head are generally formed in the following steps. First, a resinate paste is thick-film printed on an insulating substrate. Next, the conductive layer is formed by firing the thick film printed resinate paste. Finally, the conductor layer is patterned by etching to form a plurality of wirings.
On the other hand, patent document 2 discloses a method for forming a wiring pattern of an electronic component or the like by gravure offset printing. The wiring pattern formed by gravure offset printing was formed by the following procedure. First, a printing paste is filled in the concave portion of the intaglio plate. Subsequently, the printing paste is transferred to a blanket. Then, the printing paste transferred to the blanket is transferred to a printing object such as a substrate. Finally, the printing paste is fired to form a wiring pattern. Since the plurality of wirings of the thermal head are formed by gravure offset printing, it is not necessary to perform a patterning process by etching, and thus it is expected to improve productivity of the thermal head.
However, in gravure offset printing, when the printing paste filled in the concave portion of the gravure plate is transferred to the blanket, if the size of the concave portion in the traveling direction of the blanket or the direction orthogonal to the traveling direction of the blanket is large, the blanket greatly sinks toward the concave portion. This may cause bleeding, sagging, or the like of the printing paste transferred to the blanket, and thus may deteriorate the printing quality. Since the plurality of lines for thermal printing have widths of different sizes, when the plurality of lines are formed by gravure offset printing, such a problem of deterioration in print quality needs to be particularly noted.
Disclosure of Invention
Problems to be solved by the invention
The present invention has been made in view of the above circumstances, and an object thereof is to provide a thermal print head which can avoid a decrease in quality of a plurality of wirings formed by gravure offset printing.
Means for solving the problems
The present invention provides a thermal print head, comprising: a substrate having a main surface facing in a thickness direction; a plurality of wires arranged on the main surface; and a resistor body which is arranged in a main scanning direction and includes a plurality of heat generating portions which are electrically connected to the plurality of wires, wherein at least one of the plurality of wires has a plurality of edges which intersect with the main scanning direction and a plurality of void portions which penetrate in the thickness direction, and each of the plurality of void portions is located between two adjacent edges of the plurality of edges.
In the practice of the present invention, it is preferable that any one of the plurality of wires is formed in a first pattern in which the plurality of edges are inner edges of the wire and the plurality of void portions are all holes, and the first pattern is a mesh shape as viewed in the thickness direction.
In the practice of the present invention, it is preferable that the plurality of void portions are arranged alternately in the wiring forming the first pattern.
In the implementation of the present invention, it is preferable that any one of the plurality of wirings is formed in a second pattern in which the plurality of edges are outer edges of the wiring and the plurality of void portions are all cutouts recessed in a direction orthogonal to a direction in which the wiring extends, and in the wiring forming the second pattern, the plurality of void portions are located on both sides in the direction orthogonal to the direction in which the wiring extends.
In the practice of the present invention, it is preferable that the wiring forming the second pattern extends in the main scanning direction.
In the implementation of the present invention, it is preferable that the plurality of void portions are arranged in a staggered manner in the main scanning direction in the wiring forming the second pattern.
In the present invention, it is preferable that the plurality of voids are triangular in shape when viewed in the thickness direction in the wiring forming the second pattern.
In the practice of the present invention, it is preferable that the plurality of wirings are composed of a material containing gold, silver, or copper.
In the embodiment of the present invention, it is preferable that the plurality of wires include a common wire having a connection portion separated from the resistor body 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 body, and the connection portion forms the first pattern.
In the practice of the present invention, it is preferable that the common wire has a land portion extending from either one of both ends of the connecting portion in the main scanning direction to a side of the connecting portion in the sub scanning direction where the resistor is located, and the land portion forms the first pattern.
In the practice of the present invention, it is preferable that the common wiring has a thin metal layer which is disposed in contact with the connection portion and extends in the main scanning direction.
In the embodiment of the present invention, it is preferable that the plurality of wires further include a plurality of individual wires each having a second strip-shaped portion extending from a side opposite to the connecting portion with respect to the resistor in the sub-scanning direction toward the resistor, and the second strip-shaped portion is located between the plurality of first strip-shaped portions adjacent to each other in the main scanning direction.
In the implementation of the present invention, it is preferable that the resistor intersects both the plurality of first strip-shaped portions and the second strip-shaped portions of the plurality of individual wires.
In the embodiment of the present invention, it is preferable that the driving circuit further includes a driving IC located on a side opposite to the resistor body with respect to the plurality of individual wires in the sub-scanning direction, and the plurality of individual wires are all electrically connected to the driving IC.
In the implementation of the present invention, it is preferable that at least one of the plurality of wirings which are located on the opposite side of the resistor body from the plurality of individual wirings in the sub-scanning direction and which are electrically connected to the driver IC extend in the main scanning direction, and the second pattern is formed.
In the practice of the present invention, it is preferable that the wiring board further includes a glaze layer laminated on the main surface, and the plurality of wires are disposed on the glaze layer in contact with each other.
In the practice of the present invention, it is preferable that each of the plurality of first strip-shaped portions and the second strip-shaped portions of the plurality of individual wires includes a section sandwiched between the glaze layer and the resistor.
Effects of the invention
According to the thermal head of the present invention, it is possible to avoid a decrease in the quality of the plurality of wirings formed by gravure offset printing.
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 (through a protective layer and a sealing resin).
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 a partially enlarged plan view of fig. 1.
Fig. 5 is a partially enlarged view of fig. 4.
Fig. 6 is a partially enlarged view of fig. 1.
Fig. 7 is a partial enlarged view of fig. 6 (through a plurality of driver ICs).
Fig. 8 is a partially enlarged view of fig. 1.
Fig. 9 is a sectional view taken along line IX-IX of fig. 8.
Fig. 10 is a sectional view taken along line X-X of fig. 8.
Fig. 11 is a sectional view illustrating a manufacturing process of the thermal head shown in fig. 1.
Fig. 12 is a sectional view illustrating a manufacturing process of the thermal head shown in fig. 1.
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 sectional view illustrating a manufacturing process of the thermal head shown in fig. 1.
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.
Detailed Description
A mode for carrying out the present invention (hereinafter, referred to as "embodiment") will be described with reference to the drawings.
[ first embodiment ]
A thermal head a10 according to an embodiment of the present invention will be described with reference to fig. 1 to 10. The thermal head a10 includes a substrate 10, a glaze layer 20, a plurality of wires 30, a resistor 40, a protective layer 50, a plurality of driver ICs 61, a sealing resin 63, a connector 64, and a heat sink 65. In these drawings, fig. 1 is illustrated with the protective layer 50 and the sealing resin 63 being transparent for easy understanding. In fig. 1, the transparent sealing resin 63 is shown by a virtual line (two-dot chain line). For ease of understanding, fig. 7 goes through a plurality of driver ICs 61. In fig. 7, a plurality of transmissive driver ICs 61 are shown by phantom lines.
As shown in fig. 3, the thermal head a10 shown in these figures is an electronic device that performs printing on a recording medium 71 such as thermal paper by selectively generating heat in a plurality of heat generating portions 41 (described in detail later) included in a resistor 40. Since the thermal head a10 has a flat surface structure, the recording medium 71 used for printing is limited to a medium that is wound in advance such as roll paper. The thermal head a10 is a so-called thick film type. The resistor 40 is formed by printing and firing in a thick film type.
For convenience of explanation, the main scanning direction of the thermal head a10 is referred to as the "x direction", and the sub-scanning direction of the thermal head a10 is referred to as the "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" means "viewed in the thickness direction".
As shown in fig. 1 and 2, the substrate 10 is a belt-like shape extending in the x direction. The substrate 10 is made of, for example, alumina (Al)2O3) Or ceramics containing aluminum nitride (AlN) as a main component. The material of the substrate 10 includes alumina or aluminum nitride and a synthetic resin binder. In addition, the material of the substrate 10 may include a light-shielding material. The light-shielding material is, for example, carbon (C). As shown in fig. 3, the substrate 10 has a main surface 10A and a back surface 10B facing opposite sides to each other in the z direction.
As shown in fig. 9 and 10, the glaze layer 20 is laminated on the main surface 10A of the substrate 10. The glaze layer 20 is made of a material containing amorphous glass. Thus, the glaze layer 20 is transparent or white. The amorphous glass is, for example, SiO2－BaO－Al2O3-SnO-ZnO glass. The surface of glaze layer 20 is smooth.
As shown in fig. 1, 9, and 10, the plurality of wires 30 are disposed on the main surface 10A of the substrate 10. In the thermal head a10, a plurality of wires 30 are arranged in contact with each other on the glaze layer 20. The plurality of wires 30 constitute a conductive path for conducting electricity between the resistor 40 and the plurality of driver ICs 61. The plurality of wirings 30 include a common wiring 31, a plurality of individual wirings 32, a plurality of input wirings 33, a plurality of connection wirings 34, and a plurality of terminals 35. Among them, if attention is paid to the common line 31 and the plurality of individual lines 32, a current flows from the plurality of individual lines 32 to the common line 31 via the resistor 40 in the thermal head a 10. Therefore, in the thermal head a10, the individual wires 32 are positive electrodes, and the common wire 31 is a negative electrode. The plurality of wires 30 are made of a material containing silver (Ag). More specifically, the plurality of wires 30 (except for the thin metal layer 314 described later) are cured from a paste of a resinate (organic metal compound) containing silver. In addition to silver, the metal contained in the resinate paste may be gold (Au) or copper (Cu). The thickness of each of the plurality of wires 30 is, for example, 0.6 μm or more and 1.2 μm or less.
As shown in fig. 1, 4, and 8, the common line 31 includes a plurality of first strip portions 311, first connecting portions 312, a pair of ground portions 313, and a thin metal layer 314. In the thermal head a10, the current flowing through the common wire 31 flows in order to the plurality of first strip portions 311, the first connecting portion 312, and the pair of ground portions 313.
As shown in fig. 1 and 4, the first connection portion 312 is separated from the resistor 40 in the y direction. The first connection portion 312 is located on the opposite side of the resistor 40 from the plurality of driver ICs 61 in the y direction. The first connecting portion 312 extends in the x direction and has a band shape with a constant width.
As shown in fig. 4 and 8, the plurality of first band-shaped portions 311 are band-shaped portions extending from the first connecting portion 312 toward the resistor 40. The maximum width of each of the plurality of first strip portions 311 is smaller than the width of the first connecting portion 312. The plurality of first band portions 311 are arranged at equal intervals in the x direction. Each of the first strip portions 311 has a base portion 311A and an extension portion 311B. The base portion 311A is rectangular when viewed along the z direction, and is connected to the first connecting portion 312. The extension 311B extends from the base 311A toward the resistor 40. The width of the extension 311B is smaller than the width (dimension in the x direction) of the base 311A. The width of the extension 311B is, for example, 25 μm or less. The base portion 311A is sandwiched between the first coupling portion 312 and the first band portion 311 in the y direction.
As shown in fig. 1 and 4, the pair of ground portions 313 are strip-shaped extending from both ends of the first connecting portion 312 in the x direction to the side of the first connecting portion 312 where the resistor 40 is located in the y direction. The common wiring 31 may have one ground portion 313 connected to either one of the two ends of the first connecting portion 312 in the x direction. In the example of the thermal head a10, each of the pair of ground portions 313 has an L shape extending from the first connecting portion 312 in the x direction and then extending toward the plurality of terminals 35. The width of each section extending in the y direction of the pair of ground connection portions 313 is larger than the width of the first connection portion 312. Each of the pair of grounding portions 313 is connected to the first strip portion 311 and any one of the plurality of terminals 35.
As shown in fig. 8, the thin metal layer 314 is disposed on the first connecting portion 312. The thin metal layer 314 extends in the x-direction. The metal thin layer 314 is, for example, a layer obtained by curing a conductive paste containing silver particles and glass frit. The resistivity of the metal thin layer 314 is smaller than the resistivity of each of the plurality of wires 30 other than the metal thin layer 314.
As shown in fig. 1, the individual wires 32 extend from any one of the driver ICs 61 toward the resistor 40. In the thermal head a10, the individual wires 32 are arranged in a plurality of bundles corresponding to the number of the drive ICs 61 mounted. In the example of the thermal head a10, the plurality of individual wires 32 are arranged in two bundles. The individual wires 32 apply voltages to individually selected portions of the resistors 40. The plurality of individual wires 32 are arranged in the x direction. As shown in fig. 4, each of the individual wires 32 includes a second strip 321, a second connecting portion 322, and a connecting portion 323.
As shown in fig. 4 and 8, the second strip-shaped portion 321 is a strip-shaped portion extending toward the resistor 40 from the opposite side of the first connection portion 312 with respect to the resistor 40 and the common line 31 in the y direction. The second strip portion 321 is located between two first strip portions 311 adjacent in the x direction among the plurality of first strip portions 311 of the common wiring line 31. The second strip 321 has a base 321A and an extension 321B. The base 321A has a rectangular shape when viewed from the z direction. The extension 321B extends from the base 321A toward the resistor 40. The width (dimension in the x direction) of the extension 321B is smaller than the width (dimension in the x direction) of the base 321A. The width of the extension 321B is, for example, 25 μm or less.
As shown in fig. 4, the second connection portion 322 is a strip-like portion extending from the base portion 321A of the second strip-like portion 321 in the direction away from the resistor 40 in the y direction. The second coupling portion 322 is connected to the base portion 321A. The second coupling portion 322 has a skew portion 322A and a parallel portion 322B. The skew portion 322A is connected to the base portion 321A and is tilted with respect to the y direction. The parallel portion 322B is connected to the skew portion 322A and is parallel to the y direction.
As shown in fig. 4, the connecting portion 323 is located on the opposite side of the second strip 321 with respect to the second connecting portion 322 in the y direction. The connection portion 323 is connected to the parallel portion 322B of the second connection portion 322. The connection portion 323 includes a first portion 323A and a second portion 323B. The second portion 323B is located farther from the resistor 40 in the y direction than the first portion 323A. Thus, the first portions 323A of the plurality of individual wires 32 and the second portions 323B of the plurality of individual wires 32 are staggered in the x direction. The width of the parallel portion 322B located between two adjacent first portions 323A among the first portions 323A of the plurality of individual wires 32 and connected to the second portion 323B is, for example, 10 μm or less.
As shown in fig. 1 and 6, the plurality of input wirings 33 are located on the opposite side of the plurality of independent wirings 32 with respect to the plurality of driver ICs 61 in the y direction. The plurality of input wirings 33 are conductive paths for electric signals input to the plurality of driver ICs 61. The number of the input wirings 33 corresponds to the number of the driver ICs 61 mounted. In the example showing the thermal head a10, two input wirings 33 separated from each other in the x direction are arranged. Each of the plurality of input wirings 33 has a strip shape extending in the x direction. The width of each of the plurality of input wirings 33 is larger than the width of the first connection portion 312 of the common wiring 31. Each of the plurality of input wirings 33 is connected to one of the plurality of terminals 35.
As shown in fig. 1 and 6, the plurality of connection wirings 34 are located on the opposite side of the resistor 40 from the plurality of individual wirings 32 in the y direction. The plurality of connection wirings 34 are conductive paths of electric signals input to the plurality of driver ICs 61 and electric signals output from the plurality of driver ICs 61. The width of each of the plurality of connection wires 34 is approximately the same as the width of each of the second connection portions 322 of the plurality of individual wires 32. Each of the plurality of connection wires 34 is connected to one of the plurality of terminals 35. Each of the plurality of connection wirings 34 includes a section extending in the x direction.
As shown in fig. 1, the plurality of terminals 35 are located on the opposite side of the plurality of input wirings 33 from the plurality of driver ICs 61 in the y direction. The plurality of terminals 35 are rectangular when viewed from the z direction. The plurality of terminals 35 are arranged along the x direction. The plurality of terminals 35 are all electrically connected to any one of the pair of grounding portions 313 of the common wiring 31, the plurality of input wirings 33, and the plurality of connection wirings 34.
In the thermal head a10, as shown in fig. 5 and 7, at least one of the plurality of wires 30 has a plurality of edges 301 and a plurality of gaps 302. A plurality of edges 301 intersect the x-direction. As shown in fig. 9 and 10, the plurality of void portions 302 penetrate at least one of the plurality of wires 30 in the z direction. As shown in fig. 5 and 7, each of the plurality of void portions 302 is located between two adjacent edges 301A and 301B of the plurality of edges 301. In the thermal head a10, the plurality of edges 301 and the plurality of gaps 302 form one of a plurality of wires 30 in a "first pattern" and a "second pattern". Fig. 5 shows a first pattern. Fig. 7 shows a second pattern.
As shown in fig. 5, the first pattern is a pattern in which a plurality of edges 301 of the plurality of wires 30 are inner edges of the wires 30 and a plurality of void portions 302 are all holes in any of the plurality of wires 30. In the first pattern, the periphery of each of the plurality of voids 302 surrounds two adjacent edges 301A, 301B of the plurality of edges 301. The first pattern is a net shape as viewed in the z-direction. In the wiring 30 forming the first pattern, a plurality of void portions 302 are staggered throughout the entirety. In the thermal head a10, as shown in fig. 4 and 6, the wirings forming the first pattern out of the plurality of wirings 30 are the first connecting portion 312 of the common wiring 31, the pair of grounding portions 313 of the common wiring 31, the plurality of input wirings 33, and the plurality of terminals 35. In addition, illustration of the plurality of terminals 35 in which the first pattern is formed is omitted.
As shown in fig. 7, the second pattern is a pattern in which a plurality of edges 301 of any of the plurality of wires 30 are outer edges of the wire and each of a plurality of voids 302 is a notch recessed in a direction orthogonal to a direction in which the wire extends. In the second pattern, the plurality of void portions 302 are sandwiched by two adjacent edges 301A, 301B of the plurality of edges 301 from both sides in the direction in which the wiring 30 extends. In the wiring 30 forming the second pattern, the plurality of void portions 302 are located on both sides in the direction orthogonal to the direction in which the wiring 30 extends.
In the thermal head a10, as shown in fig. 6, the wires forming the second pattern among the plurality of wires 30 are sections extending in the x direction included in each of the plurality of connection wires 34. Therefore, the wiring 30 forming the second pattern extends in the x direction. As shown in fig. 7, in the wiring forming the second pattern, a plurality of void portions 302 are staggered in the x direction. The plurality of voids 302 are all triangular in shape when viewed in the z direction. Thus, the wiring forming the second pattern has a zigzag shape as viewed from the z direction.
As shown in FIG. 1The resistor 40 is shown as a strip extending in the x direction. The resistor 40 is disposed on the glaze layer 20 in contact therewith. The resistor 40 intersects both the plurality of first strip-shaped portions 311 of the common line 31 and the second strip-shaped portions 321 of the plurality of individual lines 32. As shown in fig. 9 and 10, each of the first strip-shaped portions 311 and the second strip-shaped portions 321 includes a section sandwiched between the glaze layer 20 and the resistor 40. Thus, the first band-shaped portions 311 and the first connecting portions 312 are partially covered by the resistor 40. The material of the resistor 40 is selected to have a resistivity higher than that of each of the plurality of wires 30. In the thermal head a10, the resistor 40 is made of, for example, ruthenium tetroxide (RuO)2) And a member obtained by curing a conductive paste of particles and glass frit. The maximum thickness of the resistor 40 is, for example, 6 μm to 10 μm.
As shown in fig. 8, the resistor 40 includes a plurality of heat generating portions 41. The plurality of heat generating portions 41 are electrically connected to the common line 31 and the plurality of individual lines 32 among the plurality of lines 30. The plurality of heat generating portions 41 are arranged in the x direction. Each of the plurality of heat generating portions 41 is sandwiched between a portion of the resistor 40 covering a portion of any one of the plurality of first strip-shaped portions 311 and a portion of the resistor 40 covering a portion of the second strip-shaped portion 321 located in the vicinity of the first strip-shaped portion 311. When the resistor 40 is selectively energized through the individual wires 32 and the common wire 31, the heat generating portions 41 selectively generate heat. Thereby, dot printing is performed on the recording medium 71 shown in fig. 3.
As shown in fig. 9 and 10, the protective layer 50 is disposed on the glaze layer 20. The protective layer 50 covers the common line 31 and a part of each of the plurality of individual lines 32 and the resistor 40 one by one. Like the glaze layer 20, the protective layer 50 is made of a material containing amorphous glass.
As shown in fig. 1, the plurality of driver ICs 61 are located on the opposite side of the resistor 40 from the plurality of individual wires 32 in the y direction. The plurality of driver ICs 61 are mounted on the glaze layer 20 via an electrically insulating paste. In the example of the thermal head a10, two drive ICs 61 are mounted on the glaze layer 20. In the example of the thermal head a10, as shown in fig. 6, the plurality of drive ICs 61 cover a part of each of the plurality of input wirings 33 and the plurality of connection wirings 34.
As shown in fig. 6, the plurality of driver ICs 61 each have a plurality of electrodes 611 provided on the upper surface thereof. One ends of the plurality of wires 62 are individually bonded to the plurality of electrodes 611. The plurality of wires 62 is made of gold, for example. The other ends of the plurality of lead wires 62 are all connected to any of the connection portions 323 of the plurality of individual wires 32, the plurality of input wires 33, and the plurality of connection wires 34. Thus, the individual wirings 32, the input wirings 33, and the connecting wirings 34 are electrically connected to any of the driver ICs 61. The plurality of driver ICs 61 selectively apply voltages to the plurality of individual wires 32 based on electrical signals input via the plurality of input wires 33 and the plurality of connection wires 34. Thereby, the plurality of heat generation portions 41 included in the resistor 40 selectively generate heat.
As shown in fig. 1 and 3, the sealing resin 63 covers the driver IC61 and the plurality of lead wires 62. In addition, the sealing resin 63 further covers a part of the plurality of wirings 30 (the connection portions 323 of the plurality of individual wirings 32, and the like) that is not covered with the protective layer 50. The sealing resin 63 is, for example, a black and soft synthetic resin for underfill.
As shown in fig. 1 to 3, the connector 64 is disposed at one end of the substrate 10 in the y direction. The connector 64 is used to connect the thermal head a10 with a thermal printer. As shown in fig. 1, the connector 64 is connected to the plurality of terminals 35. Thus, the connector 64 is electrically connected to the independent wires 32 via the input wires 33, the connection wires 34, and the driver ICs 61. The connector 64 is electrically connected to the pair of ground portions 313 of the common wiring 31.
As shown in fig. 2 and 3, the heat sink 65 is bonded to the back surface 10B of the substrate 10 via a bonding material (not shown). The bonding material is, for example, a double-sided tape having high thermal conductivity. The heat sink 65 is made of, for example, aluminum (Al).
Next, the operation of the thermal head a10 will be described.
As shown in fig. 3, the heat generating portions 41 (resistors 40) of the thermal head a10 face the platen roller 72 incorporated in the thermal printer via the protective layer 50. The recording medium 71 is sandwiched between the platen roller 72 and a region of the protective layer 50 covering the plurality of heat generating portions 41. When the thermal printer is operated, the platen roller 72 rotates to convey the recording medium 71 at a constant speed. At this time, if the plurality of heat generating portions 41 selectively generate heat, the heat is transferred to the recording medium 71 through the protective layer 50, whereby printing is performed on the recording medium 71. At the same time, heat emitted from the plurality of heat generating portions 41 is also transferred to the glaze layer 20. A part of the heat is accumulated in the glaze layer 20. The residual heat is released to the outside of the thermal head a10 through the substrate 10 and the heat sink 65.
Next, an example of a method for manufacturing the thermal head a10 will be described with reference to fig. 11 to 17. The cross-sectional positions in fig. 11 to 17 are the same as those in fig. 9.
First, as shown in fig. 11, a substrate 10 is prepared. The substrate 10 is a ceramic containing alumina or aluminum nitride as a main component.
Next, as shown in fig. 12, the glaze layer 20 is formed to be laminated on the main surface 10A of the substrate 10. The glaze layer 20 is formed by thick-film printing a paste of amorphous glass and then firing the paste.
Next, as shown in fig. 13 to 15, a plurality of lines 30 arranged in contact with the glaze layer 20 are formed by gravure offset printing.
First, as shown in fig. 13, after a printing paste 82 is filled in a recessed plate 81 having a plurality of recesses 811, the printing paste 82 is transferred to a blanket 83 rotating at a predetermined angular velocity. The plurality of concave portions 811 are recessed from the surface of the depressed plate 81 facing the z direction. A plurality of projections 811A projecting from the bottom surface of the recess 811 are formed in any one of the plurality of recesses 811. The printing paste 82 is a resinate paste containing silver. The blanket 83 rotates in the direction of the arrow shown in fig. 13. Thus, in this step, the blanket 83 travels from the left side to the right side in fig. 13 in the y direction. When the printing paste 82 filled in the concave portion 811 where the plurality of protrusions 811A are formed is transferred to the blanket 83, the plurality of voids 821 are formed in the printing paste 82. The positions, shapes, and sizes of the voids 821 correspond to the projections 811A.
Next, as shown in fig. 14, the printing paste 82 transferred to the blanket 83 is transferred to the surface of the glaze layer 20 facing the z direction. The blanket 83 rotates in the direction of the arrow shown in fig. 14. Thus, in this step, the blanket 83 travels from the right side to the left side in fig. 14 in the y direction.
Finally, as shown in fig. 15, the printing paste 82 transferred to the surface of the glaze layer 20 facing the z direction is fired to form a plurality of wirings 30. At this time, the plurality of voids 821 formed in the print paste 82 are the plurality of voids 302 of at least one of the plurality of wires 30 (the first connecting portion 312 of the common wire 31 in fig. 15). As described above, the plurality of wirings 30 are formed by gravure offset printing. In this step, after the plurality of lines 30 are formed by gravure offset printing, the thin metal layer 314 laminated on the first connecting portion 312 of the common line 31 is formed. The metal thin layer 314 is formed by thick-film printing a conductive paste containing silver particles and a glass frit, and then firing the printed conductive paste.
Next, as shown in fig. 16, a resistor 40 is formed to be electrically connected to the plurality of wires 30. In forming the resistor 40, first, a conductive paste containing ruthenium tetroxide particles and glass frit and having a high resistivity is thick-film printed in a strip shape extending in the x direction so as to be in contact with both the glaze layer 20 and the plurality of wires 30. Next, the thick film printed conductive paste is fired. Finally, the resistor 40 is formed by appropriately performing fine adjustment for adjusting the resistance value with respect to the conductive paste cured by firing.
Next, as shown in fig. 17, a protective layer 50 is formed so as to be in contact with the glaze layer 20 and cover a part of the plurality of wires 30 and the resistor 40. The protective layer 50 is formed by thick-film printing a paste of amorphous glass and then firing the paste.
After the protective layer 50 is formed, a plurality of driver ICs 61 are mounted on the surface of the glaze layer 20 facing the z direction by die bonding. Next, the plurality of wires 62 are formed by wire bonding, and then, the sealing resin 63 covering the plurality of driver ICs 61 and the plurality of wires 62 is formed. Subsequently, the substrates 10 are cut one by one along the y direction. Finally, the thermal head a10 can be obtained by mounting the connector 64 and the heat sink 65 on the board 10.
Next, the operation and effect of the thermal head a10 will be described.
According to the thermal head a10, at least one of the wires 30 has a plurality of edges 301 intersecting the x direction and a plurality of gaps 302 penetrating in the z direction. The plurality of voids 302 are each located between adjacent two of the plurality of rims 301. The pattern of the wiring 30 corresponds to the shape of the plurality of recesses 811 of the depressed plate 81 in the step shown in fig. 13. In the example shown in fig. 13, a plurality of protrusions 811A are formed in any one of a plurality of recesses 811. This suppresses significant sinking of blanket 83 into recess 811 even if the area of recess 811 viewed in the z direction is large. Therefore, in the step shown in fig. 13, the printing paste 82 transferred to the blanket 83 is prevented from bleeding, sagging, or the like. Therefore, according to the thermal head a10, it is possible to avoid a decrease in the quality of the plurality of wirings 30 formed by gravure offset printing.
In the thermal head a10, the first pattern and the second pattern are formed by the pattern formed by the plurality of edges 301 and the plurality of gaps 302 of at least one of the plurality of wires 30. The first pattern and the second pattern are effective shapes for avoiding a decrease in quality of the plurality of wirings 30 formed by gravure offset printing.
In the first pattern, the edges 301 are inner edges of the wiring 30, and the voids 302 are holes. Thus, the first pattern is a mesh when viewed in the z-direction. The first pattern is effective in avoiding a decrease in the quality of the wiring 30 having a large width among the plurality of wirings 30.
In addition, in the wiring 30 forming the first pattern, a plurality of void portions 302 are arranged alternately. This can reduce the number of the plurality of voids 302 while suppressing a large sinking of the blanket 83 into the recess 811 in the step shown in fig. 13. Therefore, an excessive increase in the resistance value of the wiring 30 forming the first pattern can be suppressed.
In the second pattern, the plurality of edges 301 are inner edges of the wiring lines 30, and the plurality of void portions 302 are each a notch recessed in a direction orthogonal to a direction in which the wiring lines 30 extend. In the wiring 30 forming the second pattern, the plurality of void portions 302 are located on both sides in the direction orthogonal to the direction in which the wiring 30 extends, and are arranged in a staggered manner along the direction in which the wiring 30 extends. When the transfer is performed to the blanket 83 in the process shown in fig. 13, the printing paste 82 serving as a base of the line 30 having a small width extending in the direction orthogonal to the traveling direction of the blanket 83 in the process shown in fig. 14 may be subjected to a false printing. Therefore, the printing paste 82 can be suppressed from being printed erroneously due to the shape of the plurality of concave portions 811 of the depressed plate 81 corresponding to the second pattern, and thus the quality of the wiring 30 can be prevented from being degraded.
The plurality of wires 30 are made of a material containing silver. That is, the printing paste 82 used when the plurality of wirings 30 are formed by gravure offset printing contains silver. Thus, in the step shown in fig. 13, when the printing paste 82 is transferred to the blanket 83, the shape of the printing paste 82 is relatively stable.
The common line 31 included in the plurality of lines 30 includes a thin metal layer 314 disposed in contact with the first connection portion 312 and extending in the x direction. Thus, since a part of the current flowing through the first connection portion 312 is shunted to the thin metal layer 314, the current can flow through the common line 31 at a high speed. Therefore, excessive heat generation of the plurality of heat generating portions 41 of the resistor 40 can be avoided. In addition, since the first connection portion 312 forms the first pattern, the resistance value of the first connection portion 312 tends to increase. Therefore, the thin metal layer 314 is an effective structure for allowing a current to flow quickly through the common line 31 formed by gravure offset printing.
The thermal head a10 further includes a glaze layer 20 laminated on the main surface 10A of the substrate 10. The plurality of wires 30 are disposed on the glaze layer 20 in contact with each other. As a result, in the step shown in fig. 14, the printing paste 82 transferred to the surface of the glaze layer 20 can be prevented from being dented or printed.
The present invention is not limited to the above-described embodiments. Various design changes can be made to the specific configuration of each part of the present invention.
Description of the symbols
A10 thermal print head
10 base plate
10A Main surface
10B back side
20 glaze layer
30 wiring
301. 301A, 301B edge
302 void portion
31 common electrode
311 first band part
311A base
311B extension part
312 first connecting part
313 ground part
314 metal thin layer
32 independent electrodes
321 second strip-shaped part
321A base part
321B extension part
322 second connecting part
322A skew
322B parallel portion
323 connecting part
323A first part
323B second part
33 input wiring
34 connecting wiring
35 terminal
40 resistor body
41 heating part
50 protective layer
61 drive IC
62 conducting wire
63 sealing resin
64 connector
65 heating radiator (heating panel)
71 recording medium
72 paper pressing roller
81 intaglio (gravure)
811 concave part
811A projection
82 printing paste
821 space part
83 blankets (blanket).
