JP2019166788A - Thermal print head - Google Patents

Abstract

To provide a thermal print head capable of improving reliability.SOLUTION: A thermal print head includes: a first substrate 1; an electrode layer 3; and a resistor layer 4 including a plurality of heating sections 40 arrayed in a main scanning direction x. The electrode layer 3 further has a second substrate 2 which has a wiring layer 23 having a plurality of first pads 31 arranged along a first end edge 131 of the first substrate located at a y end in a sub-scanning direction of the first substrate 1 and a plurality of second pads 24 joined to the plurality of first pads 131 through a conductive joining material 6 and a support layer 21 which is made of an insulation material for supporting the wiring layer 23 and has flexibility. Each of the second pads 24 has a first section 241 of the second pad overlapped with the first substrate 1 in a thickness direction z view of the first substrate 1 and a second section 242 of the second pad exposed in a sub-scanning direction y from the first end edge 131 of the first substrate. A sub-scanning direction y dimension of the second section 242 of the second pad is larger than a main scanning direction x dimension of the second section 242 of the second pad.SELECTED DRAWING: Figure 5

Description

  The present disclosure relates to a thermal printhead.

  Patent Document 1 discloses an example of a conventional thermal print head. The thermal print head disclosed in this document includes a substrate, an electrode layer, a resistor layer, and a protective layer. The resistor layer has a plurality of heat generating portions. By selectively energizing the plurality of heat generating portions through the electrode layer, printing is performed on thermal paper or the like to be printed.

  The poor continuity of the thermal print head causes a malfunction of the thermal print head A1 and is one factor that lowers the reliability.

Japanese Patent Laid-Open No. 10-16268

  The present disclosure has been conceived under the above circumstances, and an object thereof is to provide a thermal print head capable of improving reliability.

  A thermal print head provided by the present disclosure includes an electrode layer and a resistor layer including a plurality of heat generating portions arranged in the main scanning direction, and the electrode layer has an end in the sub scanning direction of the first substrate. A wiring having a plurality of first pads arranged along the first edge of the first substrate located on the substrate and having a plurality of second pads bonded to the plurality of first pads via a conductive bonding material. And a second substrate comprising a flexible support layer made of an insulating material that supports the wiring layer and the wiring layer, wherein the second pad is the first substrate as viewed in the thickness direction of the first substrate. A second pad first portion that overlaps the substrate; and a second pad second portion that is exposed in the sub-scanning direction from the first edge of the first substrate; and a dimension in the sub-scanning direction of the second pad second portion. Is larger than the dimension of the second pad second part in the main scanning direction.

  According to the thermal print head of the present disclosure, the reliability can be improved.

  Other features and advantages of the present disclosure will become more apparent from the detailed description given below with reference to the accompanying drawings.

It is a top view showing a thermal print head concerning a 1st embodiment of this indication. It is sectional drawing which follows the II-II line | wire of FIG. It is a principal part enlarged plan view showing the thermal print head concerning a 1st embodiment of this indication. It is a principal part expanded sectional view which shows the thermal print head which concerns on 1st Embodiment of this indication. It is a principal part expanded sectional view which shows the thermal print head which concerns on 1st Embodiment of this indication. It is a principal part enlarged plan view showing the thermal print head concerning a 1st embodiment of this indication. It is a principal part enlarged plan view showing the thermal print head concerning a 1st embodiment of this indication. It is a principal part enlarged bottom view showing a thermal print head concerning a 1st embodiment of this indication. It is a principal part enlarged bottom view showing a thermal print head concerning a 1st embodiment of this indication. It is a partial cross section principal part expansion perspective view which shows the electroconductive joining material of the thermal print head which concerns on 1st Embodiment of this indication. It is a principal part enlarged plan view which shows the thermal print head of a reference example. It is a principal part bottom view showing the modification of the 2nd substrate of the thermal print head concerning a 1st embodiment of this indication.

  Hereinafter, preferred embodiments of the present disclosure will be specifically described with reference to the drawings.

  The terms “first”, “second”, “third”, and the like in this disclosure are merely used as labels, and are not intended to permutate those objects.

  1 to 10 show an example of a thermal print head according to the present invention. The thermal print head A1 of this embodiment includes a first substrate 1, a second substrate 2, an electrode layer 3, a resistor layer 4, a protective layer 5, a conductive bonding material 6, a driving IC 71, a sealing resin 72, and a heat dissipation member 75. It has. The thermal print head A1 is incorporated in a printer that performs printing on thermal paper in order to create, for example, a barcode sheet or a receipt. For convenience of understanding, the protective layer 5 is omitted in FIGS. 1 and 3. In these drawings, the main scanning direction is the x direction, the sub scanning direction is the y direction, and the thickness direction of the first substrate 1 is the z direction.

  FIG. 1 is a plan view showing the thermal print head A1. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is an enlarged plan view of a main part showing the thermal print head A1. FIG. 4 is an enlarged sectional view of a main part showing the thermal print head A1. FIG. 5 is an enlarged cross-sectional view of a main part showing the thermal print head A1. FIG. 6 is an enlarged plan view of a main part showing the thermal print head A1. FIG. 7 is an enlarged plan view of a main part showing the thermal print head A1. FIG. 8 is an enlarged bottom view of the main part showing the thermal print head A1. FIG. 9 is an enlarged bottom view of the main part showing the thermal print head A1. FIG. 10 is an enlarged perspective view of a partial cross-sectional main part showing the conductive bonding material of the thermal print head according to the first embodiment of the present disclosure.

The first substrate 1 has a base material 11 and a glaze layer 12. Substrate 11, for example AlN, a ceramic such as Al ₂ O _3, for example, its thickness is about 0.6 to 1.0 mm. As shown in FIG. 1, the first substrate 1 has a long rectangular shape extending long in the main scanning direction x. The first substrate 1 has a first substrate first edge 131 and a first substrate second edge 132. The first substrate first edge 131 is an edge located on the upstream side in the sub-scanning direction y. The first substrate second edge 132 is an edge located downstream in the sub-scanning direction y. A heat radiating member 75 made of a metal such as Al is provided on the lower surface of the first substrate 1.

  The glaze layer 12 is formed on the base material 11 and is made of a glass material such as amorphous glass. The softening point of this glass material is, for example, 800 to 850 ° C. The glaze layer 12 is formed by firing a thick film of glass paste and then baking it. In the present embodiment, the glaze layer 12 has a bulging portion 121 and an auxiliary portion 122.

  The bulging portion 121 has a shape that bulges from the base material 11 in the thickness direction z, and extends long in the x direction. The auxiliary portions 122 are provided on both sides in the y direction of the bulging portion 121 and are flat portions that cover most of the base material 11. In addition, the glaze layer 12 is not limited to such a structure, For example, the whole may be a flat shape.

  The electrode layer 3 is for constituting a path for energizing the resistor layer 4 and is formed of a conductive material.

  The electrode layer 3 is formed on the glaze layer 12, and is made of, for example, Au, Pt, or Ag to which rhodium, vanadium, bismuth, silicon, or the like is added as an additive element. The thickness of the electrode layer 3 is, for example, about 0.4 to 2.5 μm. The electrode layer 3 is formed by, for example, printing a resinate Au paste containing an organic compound or a glass frit Ag paste containing Ag and glass frit, and then baking the paste.

  As shown in FIG. 3, the electrode layer 3 includes a common electrode 33, a plurality of individual electrodes 36, and a plurality of first pads 31. The illustrated common electrode 33 and individual electrode 36 are preferably portions containing Au.

  The common electrode 33 has a plurality of common electrode strips 34 and a common electrode connection part 35. The common electrode coupling portion 35 is disposed near the downstream end in the sub-scanning direction y of the first substrate 1 and has a strip shape extending in the main scanning direction x along the first substrate second end edge 132. Each of the plurality of common electrode strips 34 extends in the sub-scanning direction y from the common electrode coupling portion 35 and is arranged at an equal pitch in the main scanning direction x. In the present embodiment, as shown in FIG. 4, an Ag layer 351 is laminated on the common electrode connecting portion 35. The Ag layer 351 is for reducing the resistance value of the common electrode connecting portion 35.

  The plurality of individual electrodes 36 are for partially energizing the resistor layer 4, and are portions having a reverse polarity with respect to the common electrode 33. The individual electrode 36 extends from the resistor layer 4 toward the drive IC 71. The plurality of individual electrodes 36 are arranged in the main scanning direction x, and each has an individual electrode strip portion 38, an individual electrode connection portion 37, and a bonding portion 39.

  Each individual electrode strip 38 is a strip extending in the sub-scanning direction y, and is positioned between two common electrode strips 34 adjacent to the common electrode 33. The individual electrode strip 38 of the individual electrode 36 and the common electrode strip 34 of the common electrode 33 have a width of, for example, 25 μm or less, and the individual electrode strip 38 of the adjacent individual electrode 36 and the common electrode of the common electrode 33 The distance from the belt-like portion 34 is, for example, 40 μm or less.

  The individual electrode connecting portion 37 is a portion extending from the individual electrode strip portion 38 toward the driving IC 71, and most of the individual electrode connecting portion 37 has a portion along the sub-scanning direction y and a portion inclined with respect to the sub-scanning direction y. . Most portions of the individual electrode connecting portion 37 have a width of, for example, 40 μm or less, and the interval between adjacent individual electrode connecting portions 37 is, for example, 40 μm or less.

  As shown in FIG. 3, the bonding portion 39 is formed at an end portion in the sub-scanning direction y of the individual electrode 36, and a wire 69 for connecting the individual electrode 36 and the drive IC 71 is bonded. Bonding portions 39 of adjacent individual electrodes 36 are alternately arranged in the sub-scanning direction y. This prevents the bonding portion 39 from interfering with each other even though the bonding portion 39 is wider than most of the individual electrode connecting portions 37.

  A portion of the individual electrode connecting portion 37 sandwiched between adjacent bonding portions 39 has the smallest width in the individual electrode 36, and the width is, for example, 10 μm or less. Further, the distance between the individual electrode connecting portion 37 and the adjacent bonding portion 39 is, for example, 10 μm or less. Thus, the common electrode 33 and the plurality of individual electrodes 36 have a fine pattern with a small line width and wiring interval. The bonding part 39 is a part containing Ag, for example.

  The resistor layer 4 is made of, for example, ruthenium oxide having a resistivity higher than that of the material constituting the electrode layer 3, and is formed in a strip shape extending in the main scanning direction x. The resistor layer 4 intersects the plurality of common electrode strips 34 of the common electrode 33 and the individual electrode strips 38 of the plurality of individual electrodes 36. Further, the resistor layer 4 is laminated on the opposite side of the first substrate 1 with respect to the plurality of common electrode strips 34 of the common electrode 33 and the individual electrode strips 38 of the plurality of individual electrodes 36. A portion of the resistor layer 4 sandwiched between the common electrode strips 34 and the individual electrode strips 38 is a heat generating portion 40 that generates heat when being partially energized by the electrode layer 3. Print dots are formed by the heat generated by the heat generating portion 40. The thickness of the resistor layer 4 is, for example, 4 μm to 6 μm.

  The protective layer 5 is for protecting the electrode layer 3 and the resistor layer 4. The protective layer 5 is made of amorphous glass, for example. However, the protective layer 5 exposes a region including the bonding portions 39 of the plurality of individual electrodes 36.

  The drive IC 71 fulfills the function of partially heating the resistor layer 4 by selectively energizing the plurality of individual electrodes 36. The driving IC 71 is provided with a plurality of pads. The pads of the drive IC 71 and the plurality of individual electrodes 36 are connected via a plurality of wires 69 bonded to each other. The wire 69 is made of Au. As shown in FIGS. 1 and 2, the drive IC 71 and the wire 69 are covered with a sealing resin 72. The sealing resin 72 is made of, for example, a black soft resin.

  The plurality of first pads 31 are used to connect the first substrate 1 and the second substrate 2. The plurality of first pads 31 are arranged in the main scanning direction x along the first substrate first edge 131 of the first substrate 1. A wiring part 301 and a wiring part 302 are connected to the plurality of first pads 31. The plurality of first pads 31 are electrically connected to the driving IC 71 via the wiring portion 301 or the wiring portion 302 and the plurality of wires 69.

  FIG. 7 shows the main part of the second substrate 2 with imaginary lines for the sake of easy understanding. In the drawing, four first pads 31 among a plurality of first pads 31 are selectively shown. The number of the first pads 31 is not particularly limited, and in the present embodiment, for example, about 20 first pads 31 are provided.

  The plurality of first pads 31 are spaced apart from the first substrate first edge 131 of the first substrate 1 upstream in the sub-scanning direction y. A portion between the first substrate first edge 131 and the first pad 31 in the sub-scanning direction y is a first substrate first portion 141. A region where the first pad 31 and a second pad 24 of the second substrate 2 described later overlap in the thickness direction z is a pad first region P1.

  The second substrate 2 is connected to the first substrate 1 and is responsible for connection with a power supply unit and a control unit of a device such as a printer in which the thermal print head A1 is incorporated. The second substrate 2 has a support layer 21, an insulating layer 22, and a wiring layer 23.

  The support layer 21 is a layer that supports the wiring layer 23. The support layer 21 is made of an insulating material and has flexibility. The specific structure of the support layer 21 is not specifically limited, As an example, the resin film which consists of polyimide resins is mentioned.

  The insulating layer 22 is a layer that sandwiches the wiring layer 23 together with the support layer 21. The insulating layer 22 is a solder resist, for example, and is a thin film made of polyimide resin, PET, or the like. The insulating layer 22 has a plurality of insulating layer first edges 221. The insulating layer first edge 221 is a portion of the edge in the sub-scanning direction y of the insulating layer 22 that overlaps the wiring layer 23 when viewed in the thickness direction z.

  The wiring layer 23 is intended to provide electrical connection between the electrode layer 3 of the thermal print head A1 and the power supply unit or control unit of the device. The wiring layer 23 is a conductor foil and is made of, for example, Cu. FIG. 8 is an enlarged bottom view of the main part of the second substrate 2 and the conductive bonding material 6 in which the main part of the first substrate 1 is indicated by imaginary lines, and FIG. 9 is a schematic diagram in which the conductive bonding material 6 is further omitted. FIG. The wiring layer 23 has a plurality of second pads 24.

  The plurality of second pads 24 are conductively bonded to the plurality of first pads 31 through the conductive bonding material 6, supported by the support layer 21, and exposed from the insulating layer 22. The plurality of second pads 24 are arranged in the main scanning direction x. The arrangement pitch of the plurality of second pads 24 is substantially the same as the arrangement pitch of the plurality of first pads 31.

  The plurality of second pads 24 include a second pad first part 241 and a second pad second part 242. The second pad first portion 241 is a portion that overlaps the first substrate 1 when viewed in the thickness direction z. The second pad second portion 242 is a portion exposed to the upstream side in the sub-scanning direction y from the first substrate first edge 131 of the first substrate 1 when viewed in the thickness direction z. In the illustrated example, the second pad 24 does not have a hole penetrating in the thickness direction.

  The wiring layer 23 has a curved edge 231. The curved edge 231 is connected to the end of the insulating layer first edge 221 adjacent in the main scanning direction x, and is covered with the insulating layer 22.

  In the example shown in FIG. 7 and FIG. The dimension y24 that is the dimension y in the sub-scanning direction of the second pad 24 is, for example, 2.491 mm. The dimension y241 that is the y dimension in the sub-scanning direction of the second pad first part 241 is, for example, 1.681 mm, and the dimension y242 that is the y dimension in the sub-scanning direction of the second pad second part 242 is, for example, 0.81 mm. is there. Further, the dimension x24 which is the dimension x in the main scanning direction of the second pad 24 is, for example, 0.726 mm. Accordingly, the dimension y242 is larger than the dimension x24. That is, the second pad second portion 242 has a long rectangular shape with the sub-scanning direction y as the longitudinal direction when viewed in the thickness direction z. Further, the distance d24 between the adjacent second pads 24 in the main scanning direction x is, for example, 0.51 mm. That is, the dimension y242 is larger than the interval d24. Further, the dimension x242 is larger than the interval d24.

  The dimension y31 which is the y dimension in the sub-scanning direction of the first pad 31 is, for example, 1.616 mm, and the dimension x31 which is the x dimension in the main scanning direction of the first pad 31 is, for example, 1.041 mm. An interval d31 in the main scanning direction x between the adjacent first pads 31 is, for example, 0.20 mm. In addition, yP1 that is the y dimension in the sub-scanning direction of the pad first region P1 is, for example, 1.329 mm, and xP1 that is the x dimension in the main scanning direction of the pad first region P1 is, for example, 0.726 mm, similarly to x24. is there. Accordingly, the dimension y242 of the second pad second portion 242 is ½ or more of the dimension yP1 of the pad first region P1. Further, the dimension y242 is larger than the dimension y141 of the first substrate first part 141. The dimension y242 is not less than ½ of the dimension y31 of the first pad 31. The dimension x31 of the first pad 31 is larger than the dimension x24 of the second pad 24.

  The conductive bonding material 6 is for connecting the first substrate 1 and the second substrate 2 and is a conductive bonding material. Examples of the conductive bonding material 6 include solder. The conductive bonding material 6 bonds the plurality of first pads 31 of the electrode layer 3 of the first substrate 1 and the plurality of second pads 24 of the wiring layer 23 of the second substrate 2 to each other.

  As shown in FIGS. 5 and 8, in this embodiment, the conductive bonding material 6 includes a conductive bonding material first part 61 and a conductive bonding material second part 62.

  The conductive bonding material first part 61 is a part of the conductive bonding material 6 that is attached to the second pad first part 241 of the second pad 24, and the second pad first part 241 when viewed in the thickness direction z. Overlap. The first part 61 of the conductive bonding material is bonded to each of the second pad 24 and the first pad 31. The conductive bonding material first part 61 is generally flattened as shown in FIG. 5 by being sandwiched between the second pad first part 241 and the first pad 31.

  The conductive bonding material second portion 62 is a portion of the conductive bonding material 6 that is attached to the second pad second portion 242 of the second pad 24, and the second pad second portion 242 when viewed in the thickness direction z. Overlap. That is, the conductive bonding material second portion 62 is exposed upstream of the first substrate 1 in the sub-scanning direction y and does not overlap the first substrate 1 when viewed in the thickness direction z. Further, as shown in FIG. 5, in the illustrated example, the conductive bonding material second portion 62 is formed in the thickness direction z by a dimension z62 with respect to the upper surface of the first substrate 1 (the upper surface of the glaze layer 12). It is a bulging shape having a thickness that protrudes downward in the figure.

  FIG. 8 is an enlarged plan view of a main part in which the conductive bonding material 6 appears, and FIG. 10 is a perspective view showing the conductive bonding material 6 as viewed from below in the thickness direction z. In the illustrated example, the conductive bonding material second portion 62 is a portion attached to the rectangular second pad second portion 242, and thus has a rectangular shape in the thickness direction z view. Further, the conductive bonding material second portion 62 has a long rectangular shape with the sub-scanning direction y as the longitudinal direction when viewed in the thickness direction z, similarly to the second pad second portion 242. In addition, the conductive bonding material second portion 62 has a plurality of ridge line portions 621. The ridge line-shaped portion 621 extends from the four corners of the second pad second portion 242 and has a shape that widens toward the most bulged portion 622 of the conductive bonding material second portion 62. As shown in the partial cross-sectional view of FIG. 10, the ridge line-shaped portion 621 has a shape that rises steeply in the thickness direction z in a portion near the four corners of the second pad second portion 242. In the illustrated example, the conductive bonding material second portion 62 has four ridge line portions 621.

  An example of the process of forming the conductive bonding material second part 62 will be given. For example, in the bonding of the first substrate 1 and the second substrate 2, the molten conductive bonding material 6 adheres to the second pad second portion 242 that faces downward in the thickness direction z (lower in the gravity direction). The adhered conductive bonding material 6 swells downward in the thickness direction z due to the balance between gravity and the surface tension and gravity due to the shape of the second pad second portion 242 and the viscosity of the molten conductive bonding material 6. Exhibits the shape. At this time, the shape of the ridge line portion 621 is exhibited at the four corners of the second pad second portion 242 where the surface tension acts more strongly. In this state, when cured by cooling or the like, the illustrated conductive bonding material 6 is obtained.

  Next, the operation of the thermal print head A1 will be described.

  According to the present embodiment, the second pad second portion 242 is exposed from the first substrate 1 in the sub-scanning direction y. The second pad second portion 242 may adhere when the conductive bonding material 6 used for bonding the first substrate 1 and the second substrate 2 is melted. If the amount of the conductive bonding material 6 is insufficient, the first pad 31 and the second pad 24 cannot be sufficiently bonded, and there is a concern about poor conduction. On the other hand, if the amount of the conductive bonding material 6 is too large, the adjacent first pads 31 and the adjacent second pads 24 may be undesirably conducted. The second pad second part 242 has the dimension y24 in the sub-scanning direction y larger than the dimension x24 in the main scanning direction x, so that the excess molten conductive bonding material 6 is removed from the second pad second part 242. Can be guided more reliably in the sub-scanning direction y. As a result, by providing a sufficient amount of the conductive bonding material 6, it is possible to prevent unsatisfactory conduction between the adjacent first pads 31 and between the adjacent second pads 24 while avoiding poor conduction. Therefore, the reliability of the thermal print head A1 can be improved.

  The dimension y24 of the second pad 24 in the sub-scanning direction y is larger than the interval 24 in the main scanning direction x of the adjacent second pads 24. This is preferable for preventing the molten conductive bonding material 6 from adhering to the second pad second portion 242 and moving toward the adjacent second pad 24.

  Further, the dimension y24 of the second pad 24 in the sub-scanning direction y is ½ or more of the dimension yP1 of the pad first region P1 in the sub-scanning direction y. The pad first region P1 is a region where the first pad 31 and the second pad first portion 241 overlap in the thickness direction z view, and the conductive bonding material first portion 61 of the conductive bonding material 6 is the first pad. 31 and a second pad first portion 241. When the size of the pad first region P1 is the above-described relationship, the conductive bonding material 6 that can sufficiently achieve the conductive bonding in the pad first region P1 is provided in the sub-scanning direction. The molten conductive bonding material 6 overflowing to the upstream side of y can be reliably attached by the second pad second portion 242.

  The dimension y24 of the second pad 24 in the sub-scanning direction y is larger than the dimension y141 of the first substrate first portion 141 in the sub-scanning direction y. This avoids unintentional retention of the molten conductive bonding material 6 in the first substrate first portion 141, and more molten conductive bonding material 6 is added to the second pad second portion 242. It is advantageous to adhere.

  Further, the dimension y24 of the second pad 24 in the sub-scanning direction y is not less than ½ of the dimension y31 of the first pad 31 in the sub-scanning direction y. Even with such a configuration, it is possible to enhance the effect of reliably adhering the molten conductive bonding material 6 overflowing upstream in the sub-scanning direction y to the second pad second portion 242.

  Since the second pad second portion 242 is rectangular in the thickness direction z, the conductive bonding material second portion 62 attached to the second pad second portion 242 is rectangular in the thickness direction z. be able to. In addition, the conductive bonding material second portion 62 of the present embodiment has a bulging shape and has four ridge line portions 621. The ridge line-shaped portion 621 having such a shape is formed as a result of the conductive bonding material 6 in a molten state being restrained by a balance between surface tension and gravity.

  That is, in the process of forming the conductive bonding material second part 62, a predetermined amount of the molten conductive bonding material 6 overflows and adheres to the second pad second part 242, but is stabilized by the balance between surface tension and gravity. Maintain the bulging shape. The four ridge line-shaped portions 621 are portions that are clearly formed mainly by the action of the surface tension when the bulging shape is maintained by such a balance.

  FIG. 11 shows a thermal print head X of a comparative example in which the dimension y242 in the sub-scanning direction y of the second pad second part 242 is shorter than the dimension x242 unlike the present embodiment. In this comparative example, when the molten conductive bonding material 6 overflows from the pad first region P 1, it adheres to the second pad second portion 242. However, since the dimension y242 of the second pad second portion 242 in the sub-scanning direction y is not sufficient, the overflowing conductive bonding material 6 has a shape that bulges downward in the thickness direction z. In this case, gravity acts beyond the surface tension, and the molten conductive bonding material 6 attached to the second pad second portion 242 swells further downward in the thickness direction z. Therefore, originally, the conductive bonding material 6 that should stay between the first pad 31 and the second pad first portion 241 in the pad first region P1 is sucked to the second pad second portion 242 side. There is concern about being issued. As a result, the amount of the conductive bonding material 6 in the pad first region P1 is insufficient, and a bonding failure between the first pad 31 and the second pad first portion 241 as illustrated may occur.

  In the present embodiment, the conductive bonding material second portion 62 having a shape in which gravity and surface tension are balanced is formed while a larger amount of the conductive bonding material 6 is attached to the second pad second portion 242. As a result, the first pad 31 and the second pad first portion 241 can be more reliably joined, and the reliability of the thermal print head A1 can be improved.

  FIG. 12 shows a modification of the second substrate 2. In the modification, the plurality of second pads 24 include second pads 24A.

  The second pad 24 </ b> A faces the first pad 31 of the first substrate 1 and is bonded to the first pad 31 by the conductive bonding material 6, but is not connected to the conduction path in the second substrate 2. It is a pad.

  Such a modification can also improve the reliability of the thermal print head A1. Further, by providing the non-conductive second pad 24A, the distance between the second pads 24 that should ensure the insulation distance is increased, or the bonding strength between the first substrate 1 and the second substrate 2 is increased. There is an effect.

  The thermal print head according to the present disclosure is not limited to the above-described embodiment. The specific configuration of each part of the thermal print head according to the present disclosure can be modified in various ways.

[Appendix 1]
A first substrate;
An electrode layer;
A resistor layer including a plurality of heat generating portions arranged in the main scanning direction,
The electrode layer has a plurality of first pads arranged along a first substrate first edge located at an end in a sub-scanning direction of the first substrate;
A second substrate comprising a wiring layer having a plurality of second pads bonded to the plurality of first pads via a conductive bonding material, and a flexible support layer made of an insulating material that supports the wiring layers. Further comprising
The second pad includes a second pad first portion that overlaps the first substrate in the thickness direction of the first substrate, and a second pad second exposed from the first edge of the first substrate in the sub-scanning direction. And
A thermal print head in which a size in the sub-scanning direction of the second part of the second pad is larger than a size of the second part of the second pad in the main scanning direction.
[Appendix 2]
The conductive bonding material includes a conductive bonding material first part attached to the second pad first part and a conductive bonding material second part attached to the second pad second part. The thermal print head described in 1.
[Appendix 3]
The thermal print head according to claim 2, wherein a dimension of the second pad second part in the sub-scanning direction is larger than an interval between the plurality of second pads in the main scanning direction.
[Appendix 4]
The sub-scanning direction dimension of the second pad second part is not less than ½ of the sub-scanning direction dimension of the pad first region where the first pad and the second pad overlap when viewed in the thickness direction. The thermal print head according to 2 or 3.
[Appendix 5]
The first substrate has a first substrate first portion located between the first substrate first edge and the first pad in the sub-scanning direction;
The thermal print head according to appendix 4, wherein a dimension of the pad second part in the sub-scanning direction is larger than a dimension of the first substrate first part in the sub-scanning direction.
[Appendix 6]
The thermal print head according to appendix 4 or 5, wherein a dimension of the second pad second part in the sub-scanning direction is not less than ½ of a dimension of the first pad in the main scanning direction.
[Appendix 7]
The thermal print head according to any one of appendices 2 to 6, wherein a dimension of the first pad in the main scanning direction is larger than a dimension of the second pad in the main scanning direction.
[Appendix 8]
The thermal print head according to any one of appendices 2 to 7, wherein the second pad has a rectangular shape when viewed in the thickness direction.
[Appendix 9]
The thermal print head according to appendix 8, wherein the second part of the conductive bonding material has a bulging shape and has four ridge line-shaped parts extending from the four corners of the second pad second part.
[Appendix 10]
The thermal print head according to any one of appendices 2 to 9, wherein the second pad does not have a hole penetrating in the thickness direction.
[Appendix 11]
The second substrate has an insulating layer covering a part of the wiring layer,
The thermal print head according to any one of appendices 2 to 10, wherein the plurality of second pads are portions exposed from the insulating layer in the wiring layer.
[Appendix 12]
The insulating layer has an insulating layer first edge in contact with the second pad;
12. The thermal print head according to appendix 11, wherein the wiring layer has a curved edge connected to an end of the insulating first edge adjacent in the main scanning direction and covered with the insulating layer.
[Appendix 13]
The thermal print head according to appendix 11 or 12, wherein the plurality of second pads include a non-conductive second pad that is not used for electrical conduction.
[Appendix 14]
The thermal print head according to any one of appendices 1 to 13, wherein the first substrate is made of ceramics.
[Appendix 15]
The thermal print head according to any one of appendices 1 to 14, wherein the electrode layer and the resistor layer are formed by printing and baking a paste containing a metal.
[Appendix 16]
The thermal print head according to appendix 15, wherein the electrode layer contains Ag.
[Appendix 17]
The thermal print head according to any one of appendices 1 to 16, wherein the wiring layer includes Cu.

A1: Thermal print head 1: First substrate 2: Second substrate 3: Electrode layer 3a: First layer 4: Resistor layer 5: Protective layer 6: Conductive bonding material 11: Substrate 12: Glaze layer 21: Support Layer 22: Insulating layer 23: Wiring layers 24, 24A: Second pad 31: First pad 33: Common electrode 34: Common electrode strip 35: Common electrode coupling part 36: Individual electrode 37: Individual electrode coupling part 38: Individual Electrode band-shaped portion 39: Bonding portion 40: Heat generating portion 61: Conductive bonding material first portion 62: Conductive bonding material second portion 69: Wire 72: Sealing resin 73: Connector 75: Heat radiation member 121: Swelling portion 122 : Auxiliary part 131: first substrate first edge 132: first substrate second edge 141: first substrate first part 221: insulating layer first edge 231: curved edge 241: second pad first part 242: second pad second part 3 01: Wiring part 302: Wiring part 351: Ag layer 621: Ridge line part 622: Most bulged part 71: Drive IC
P1: Pad first region x24, x242, x31, xP1, y141, y24, y241, y242, y31, yP1, z62: Dimension x: Main scanning direction y: Sub scanning direction z: Thickness direction

Claims (17)

A first substrate;
An electrode layer;
A resistor layer including a plurality of heat generating portions arranged in the main scanning direction,
The electrode layer has a plurality of first pads arranged along a first substrate first edge located at an end in a sub-scanning direction of the first substrate;
A second substrate comprising a wiring layer having a plurality of second pads bonded to the plurality of first pads via a conductive bonding material, and a flexible support layer made of an insulating material that supports the wiring layers. Further comprising
The second pad includes a second pad first portion that overlaps the first substrate in the thickness direction of the first substrate, and a second pad second exposed from the first edge of the first substrate in the sub-scanning direction. And
A thermal print head in which a size in the sub-scanning direction of the second part of the second pad is larger than a size of the second part of the second pad in the main scanning direction.   The conductive bonding material has a conductive bonding material first part attached to the second pad first part and a conductive bonding material second part attached to the second pad second part. The thermal print head according to 1.   3. The thermal print head according to claim 2, wherein a dimension of the second pad second part in the sub-scanning direction is larger than an interval in the main scanning direction of the plurality of second pads.   The sub-scanning direction dimension of the second pad second part is ½ or more of the sub-scanning direction dimension of the pad first region where the first pad and the second pad overlap when viewed in the thickness direction. Item 4. The thermal print head according to Item 2 or 3. The first substrate has a first substrate first portion located between the first substrate first edge and the first pad in the sub-scanning direction;
5. The thermal print head according to claim 4, wherein a dimension of the pad second part in the sub-scanning direction is larger than a dimension of the first part of the first substrate in the sub-scanning direction.   6. The thermal print head according to claim 4, wherein a dimension of the second pad second part in the sub-scanning direction is not less than ½ of a dimension of the first pad in the main scanning direction.   The thermal print head according to claim 2, wherein a dimension of the first pad in the main scanning direction is larger than a dimension of the second pad in the main scanning direction.   The thermal print head according to claim 2, wherein the second pad has a rectangular shape when viewed in the thickness direction.   9. The thermal print head according to claim 8, wherein the second part of the conductive bonding material has a bulging shape and has four ridge lines that extend from the four corners of the second pad second part.   The thermal print head according to claim 2, wherein the second pad does not have a hole penetrating in the thickness direction. The second substrate has an insulating layer covering a part of the wiring layer,
The thermal print head according to claim 2, wherein the plurality of second pads are portions exposed from the insulating layer in the wiring layer. The insulating layer has an insulating layer first edge in contact with the second pad;
The thermal print head according to claim 11, wherein the wiring layer has a curved edge connected to an end of the insulating first edge adjacent in the main scanning direction and covered with the insulating layer.   The thermal print head according to claim 11, wherein the plurality of second pads include non-conductive second pads that are not used for electrical conduction.   The thermal print head according to claim 1, wherein the first substrate is made of ceramics.   The thermal print head according to claim 1, wherein the electrode layer and the resistor layer are formed by printing and baking a paste containing a metal.   The thermal print head according to claim 15, wherein the electrode layer contains Ag.   The thermal print head according to claim 1, wherein the wiring layer contains Cu.

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