JP2015193110A - thermal print head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal print head in which an electrostatic breakdown can be suppressed.SOLUTION: A thermal print head A1 comprises a base material 1, a plurality of heat generating portions 211 that are supported by the base material 1 and arrayed in a main scanning direction and a protecting layer 3 that covers the plurality of heat generating portions 211. In the protecting layer 3, sites contacting the plurality of heat generating portions 211 are formed of insulating materials; at least parts of outer surfaces positioned at opposite sides of the plurality of heat generating portions are formed of conductive materials; and the sites formed of conductive materials of the protecting layer 3 are connected to the ground.

Description

  The present invention relates to a thermal print head.

  The thermal print head is a main component device of a thermal printer that prints on thermal paper or the like. Patent Document 1 discloses an example of a conventional thermal print head. In the thermal print head disclosed in this document, a resistor layer and an electrode layer are laminated on a substrate. By patterning these resistor layers and electrode layers, a plurality of heat generating portions arranged in the main scanning direction are constituted by the resistor layers. The resistor layer and the electrode layer are covered with an insulating protective layer. The protective layer is for avoiding damage to the electrode layer and the resistor layer due to friction with thermal paper or the like.

  When printing using the thermal print head is performed, the protective layer and the thermal paper are rubbed continuously. Due to this friction, static electricity is charged in the protective layer. If excessive static electricity is charged, the thermal print head may cause electrostatic breakdown.

JP 2013-248756 A

  The present invention has been conceived under the above circumstances, and an object thereof is to provide a thermal print head capable of suppressing electrostatic breakdown.

  A thermal print head provided by the present invention includes a base material, a plurality of heat generating parts supported by the base material and arranged in a main scanning direction, and a protective layer covering the plurality of heat generating parts. In the thermal print head, the protective layer is made of an insulating material at a portion in contact with the plurality of heat generating portions, and at least a part of an outer surface located on the opposite side to the plurality of heat generating portions in the thickness direction. Is made of a conductive material, and a portion of the protective layer made of the conductive material is grounded.

  In preferable embodiment of this invention, the wiring layer which has the ground connection part which should be supported by the said base material and should be ground-connected is provided.

  In preferable embodiment of this invention, the electrically-conductive member which connects the said ground connection part of the said wiring layer and the said outer surface of the said protective layer is provided.

  In a preferred embodiment of the present invention, the conductive member contains Ag.

  In a preferred embodiment of the present invention, the protective layer has an insulating layer made of an insulating material in contact with the plurality of heat generating portions, and a conductive layer made of a conductive material formed on the insulating layer. .

  In a preferred embodiment of the present invention, the conductive layer covers the plurality of heat generating portions.

  In a preferred embodiment of the present invention, the conductive layer is formed over the entire surface of the protective layer.

  In a preferred embodiment of the present invention, each of the insulating layer and the conductive layer is covered with the conductive member and has an edge that coincides in plan view.

  In a preferred embodiment of the present invention, the conductive layer is thicker than the insulating layer.

In a preferred embodiment of the present invention, the insulating layer is made of SiO _2.

  In a preferred embodiment of the present invention, the conductive layer is made of C / SiC, SiN, or SiALON.

  In preferable embodiment of this invention, the said wiring layer has a lower layer located in the said base material side, and an upper layer formed on this lower layer.

  In a preferred embodiment of the present invention, the conductive member is in contact with an extending portion extending from the upper layer in the lower layer of the ground connection portion.

  In preferable embodiment of this invention, the protective member which covers the said electrically-conductive member is provided.

  In a preferred embodiment of the present invention, the protective member covers at least a part of the protective layer.

  In a preferred embodiment of the present invention, the protective member covers at least a part of the wiring layer.

  In a preferred embodiment of the present invention, the protection member covers all of the extending portions of the lower layer of the wiring layer.

  In a preferred embodiment of the present invention, the protective member covers at least a part of the upper layer of the wiring layer.

  In a preferred embodiment of the present invention, the protective layer has an insulating layer made of an insulating material in contact with the plurality of heat generating portions, and a conductive layer made of a conductive material formed on the insulating layer. In addition, at least a part of the ground connection portion is covered, and the conductive layer is in contact with the ground connection portion.

  In a preferred embodiment of the present invention, the conductive layer covers the plurality of heat generating portions.

  In a preferred embodiment of the present invention, the conductive layer is formed over the entire surface of the protective layer.

  In a preferred embodiment of the present invention, the insulating layer covers at least a part of the ground connection portion, and has an opening for contacting the conductive layer with the ground connection portion.

  In a preferred embodiment of the present invention, each of the insulating layer and the conductive layer has edges that do not coincide with each other in plan view.

  In a preferred embodiment of the present invention, the conductive layer is thicker than the insulating layer.

In a preferred embodiment of the present invention, the insulating layer is made of SiO _2.

  In a preferred embodiment of the present invention, the conductive layer is made of C / SiC, SiN, or SiALON.

  In preferable embodiment of this invention, the said wiring layer has the lower layer located in the said base material side, and the upper layer formed on this lower layer.

  In a preferred embodiment of the present invention, the conductive layer is in contact with an extending portion extending from the upper layer in the lower layer of the ground connection portion.

  In preferable embodiment of this invention, the protective member which covers the said electrically-conductive member is provided.

  In a preferred embodiment of the present invention, the protective member covers at least a part of the protective layer.

  In a preferred embodiment of the present invention, the protective member covers at least a part of the wiring layer.

  In a preferred embodiment of the present invention, the protection member covers all of the extending portions of the lower layer of the wiring layer.

  In a preferred embodiment of the present invention, the protective member covers at least a part of the upper layer of the wiring layer.

  In a preferred embodiment of the present invention, the lower layer of the wiring layer is a resistor layer having portions constituting the plurality of heat generating portions.

In a preferred embodiment of the present invention, the resistor layer is made of TaSiO ₂ or TaN.

  In a preferred embodiment of the present invention, the upper layer is an electrode layer made of a material having an electric resistance smaller than that of the resistor layer.

  In a preferred embodiment of the present invention, the electrode layer is made of Al.

  In a preferred embodiment of the present invention, the electrode layer has a plurality of individual electrodes each extending to the plurality of heat generating portions.

  In a preferred embodiment of the present invention, the electrode layer has a common electrode having a plurality of comb-tooth portions arranged to face the individual electrodes with the plurality of heat generating portions interposed therebetween in the sub-scanning direction.

  In a preferred embodiment of the present invention, a sub-board disposed adjacent to the base material in the sub-scanning direction, and a driver mounted on the sub-board and controlling heat generation in the plurality of heat generating portions IC.

  In a preferred embodiment of the present invention, a sealing member for sealing the driver IC is provided.

  In a preferred embodiment of the present invention, the sub-board has a ground line, and the ground connection portion and the ground line are connected via a wire.

  In a preferred embodiment of the present invention, the sealing member seals the wire.

  In a preferred embodiment of the present invention, a driver IC is provided that is supported by the base material and controls heat generation at the plurality of heat generating portions.

  In a preferred embodiment of the present invention, the driver IC is flip-chip mounted on the wiring layer.

  In preferable embodiment of this invention, the flexible wiring board connected to the said wiring layer is provided.

  In preferable embodiment of this invention, the heat radiating member joined to the opposite side to the said several heat-emitting part with respect to the said base material is provided.

  In preferable embodiment of this invention, the said base material consists of ceramics.

  According to the present invention, the outer surface of the protective layer is made of a conductive material, and the outer surface is grounded. Accordingly, even when the protective layer and the thermal paper are continuously rubbed when the thermal print head is used, static electricity generated thereby is discharged from the outer surface of the protective layer by ground connection. Therefore, it is possible to prevent excessive static electricity from being charged in the protective layer, and to suppress electrostatic breakdown of the thermal print head.

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

It is a top view which shows the thermal print head based on 1st embodiment of this invention. It is a principal part top view which shows the thermal print head of FIG. It is sectional drawing which follows the III-III line of FIG. It is sectional drawing which follows the IV-IV line of FIG. It is a principal part expanded sectional view which shows the thermal print head of FIG. It is a principal part expanded sectional view which shows the thermal print head of FIG. FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a method for manufacturing the thermal print head of FIG. 1. FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a method for manufacturing the thermal print head of FIG. 1. FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a method for manufacturing the thermal print head of FIG. 1. FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a method for manufacturing the thermal print head of FIG. 1. FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a method for manufacturing the thermal print head of FIG. 1. FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a method for manufacturing the thermal print head of FIG. 1. FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a method for manufacturing the thermal print head of FIG. 1. FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a method for manufacturing the thermal print head of FIG. 1. FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a method for manufacturing the thermal print head of FIG. 1. FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a method for manufacturing the thermal print head of FIG. 1. FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a method for manufacturing the thermal print head of FIG. 1. FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a method for manufacturing the thermal print head of FIG. 1. FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a method for manufacturing the thermal print head of FIG. 1. FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a method for manufacturing the thermal print head of FIG. 1. FIG. 3 is an enlarged cross-sectional view of a main part showing an example of a method for manufacturing the thermal print head of FIG. 1. It is a top view which shows the thermal print head based on 2nd embodiment of this invention. It is a top view which shows the thermal print head based on 3rd embodiment of this invention. It is a principal part enlarged plan view which shows the thermal print head of FIG. It is a principal part expanded sectional view which shows the thermal print head based on 4th embodiment of this invention. It is principal part expanded sectional drawing which shows an example of the manufacturing method of the thermal print head of FIG. It is principal part expanded sectional drawing which shows an example of the manufacturing method of the thermal print head of FIG. It is principal part expanded sectional drawing which shows an example of the manufacturing method of the thermal print head of FIG. It is sectional drawing which shows the thermal print head based on 5th embodiment of this invention. It is sectional drawing which shows the thermal print head based on 5th embodiment of this invention.

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

  1 to 6 show a thermal print head according to a first embodiment of the present invention. The thermal print head A1 of the present embodiment includes a base material 1, a wiring layer 2, a protective layer 3, a conductive member 4, a driver IC 5, a sub board 6, and a heat radiating member 7.

  FIG. 1 is a plan view showing a thermal print head A1 of the present invention. FIG. 2 is a plan view of an essential part showing the thermal print head A1. 3 is a cross-sectional view taken along line III-III in FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 is an enlarged cross-sectional view of a main part showing the thermal print head of FIG. FIG. 6 is an enlarged cross-sectional view of a main part showing the thermal print head of FIG. In these drawings, the main scanning direction is the x direction, and the sub scanning direction is the y direction. Moreover, in FIG. 1, 3 and the electrically-conductive member 4 are abbreviate | omitted for convenience of understanding.

  The base material 1 serves as a base of the thermal print head A1, and the surface preferably exhibits insulating properties. Although the material of the base material 1 is not specifically limited, In this embodiment, the case where it consists of ceramics, such as an alumina, is demonstrated to an example. The substrate 1 has a long rectangular shape that extends long in the x direction. The substrate 1 has a main surface 11 and a back surface 12 that face opposite sides in the z direction. A glaze layer 13 is formed on the main surface 11 of the substrate 1. The glaze layer 13 is made of a glass material such as amorphous glass. The glaze layer 13 has a strip shape extending long in the x direction, and has a shape in which a cross section in the yz plane slightly bulges in the z direction. Note that the glaze layer 13 may be formed on the entire main surface 11 of the substrate 1.

  The wiring layer 2 constitutes a path through which a current flows in the thermal print head A1, and is formed on the main surface 11 of the substrate 1 in this embodiment. The wiring layer 2 may have a portion formed in a portion other than the main surface 11 of the substrate 1. The wiring layer 2 includes a resistor layer 21 and an electrode layer 22. The resistor layer 21 corresponds to the lower layer referred to in the present invention, and the electrode layer 22 corresponds to the upper layer referred to in the present invention. In the present embodiment, the resistor layer 21 and the electrode layer 22 will be described by taking, as an example, a configuration formed by a film forming technique such as sputtering described later, but is not limited thereto. For example, the resistor layer 21 and the electrode layer 22 may be formed by finely printing a paste containing a metal component and firing the paste. Further, the positional relationship between the resistor layer 21 and the electrode layer 22 with respect to the substrate 1 can be set as appropriate. The wiring layer 2 is patterned in the shape shown in FIGS.

The resistor layer 21 is formed on the main surface 11 of the substrate 1 and the glaze layer 13. The resistor layer 21 has a plurality of heat generating portions 211. The plurality of heat generating portions 211 are arranged in a row in the x direction on the glaze layer 13. Heat generated by current flowing through these heat generating portions 211 becomes a heat source for printing by the thermal print head A1. Examples of the material of the resistor layer 21 include TaSiO _{2 and} TaN. Further, the thickness of the resistor layer 21 is not particularly limited, but an example thereof is, for example, about 0.05 μm to 0.2 μm.

  The electrode layer 22 is formed on the resistor layer 21 and is made of a material having a resistance value smaller than that of the resistor layer 21. Examples of such a material of the electrode layer 22 include Al, but are not limited thereto. For example, Cu or Au may be used. The thickness of the electrode layer 22 is not particularly limited, but an example thereof is, for example, about 0.5 μm to 2.0 μm.

  In the present embodiment, the resistor layer 21 exists in the entire region where the wiring layer 2 shown in FIGS. 1 and 2 is formed. On the other hand, the electrode layer 22 exposes part of the resistor layer 21 as appropriate. Specifically, the electrode layer 22 has a plurality of individual electrodes 221 and a common electrode 222. Each of the plurality of individual electrodes 221 has a strip shape extending along the y direction, and extends to the plurality of heat generating portions 211. The common electrode 222 has a plurality of comb-tooth portions 223 and a detour portion 224. Each of the plurality of comb-tooth portions 223 is disposed to face the individual electrode 221 with the heat generating portion 211 interposed therebetween in the y direction. That is, portions of the resistor layer 21 that are exposed from the electrode layer 22 between the plurality of individual electrodes 221 and the plurality of comb-tooth portions 223 are the plurality of heat generating portions 211. The detour portion 224 is connected to a plurality of comb-tooth portions 223, and has a portion extending in the x direction from the main surface 11 of the substrate 1, and a portion extending from the end portion in the y direction.

  Further, the wiring layer 2 has a ground connection portion 23. The ground connection portion 23 is a portion that is grounded. The shape of the ground connection portion 23 is not particularly limited, but in the present embodiment, it is rectangular in plan view as shown in FIG. Moreover, in this embodiment, the ground connection part 23 is arrange | positioned near the x direction one end of the base material 1, as shown in FIG.1 and FIG.2. More specifically, the ground connection portion 23 is disposed between the plurality of individual electrodes 221 and the portion of the detour portion 224 of the common electrode 222 that extends in the y direction in the x direction.

  As shown in FIGS. 4 and 6, the ground connection portion 23 is formed by part of the resistor layer 21 and the electrode layer 22. Although such a configuration is preferable for convenience in the manufacturing method described later, the ground connection portion 23 may be formed by only one of the resistor layer 21 and the electrode layer 22. Further, the ground connection portion referred to in the present invention may be configured by a member different from the wiring layer 2. In the ground connection portion 23, a part of the resistor layer 21 extends from the electrode layer 22. This portion is an extended portion 231. The extending portion 231 extends from the resistor layer 21 toward the side where the plurality of heat generating portions 211 exist in the y direction.

  The protective layer 3 is for protecting the resistor layer 21. As shown in FIG. 2, the protective layer 3 covers at least the plurality of heat generating portions 211, and covers almost all of the wiring layer 2 in this embodiment. The protective layer 3 is made of an insulating material at a portion in contact with the plurality of heat generating portions 211, and at least a part of the outer surface 30 located on the side opposite to the plurality of heat generating portions 211 in the thickness direction is made of a conductive material. . As a specific configuration for realizing such a configuration, in the present embodiment, the protective layer 3 includes an insulating layer 31 and a conductive layer 32.

The insulating layer 31 is formed on the main surface 11 of the substrate 1 and is in contact with the plurality of heat generating portions 211. The insulating layer 31 is made of an insulating material. Such an insulating material is not particularly limited, and an example thereof is SiO ₂ . The thickness of the insulating layer 31 is not particularly limited, but an example is about 0.6 μm to 2.0 μm.

  The conductive layer 32 is formed on the insulating layer 31 and is made of a conductive material. Such a conductive material is not particularly limited, and examples thereof include C / SiC, SiN, and SiALON. The thickness of the conductive layer 32 is not particularly limited, but an example is about 4.0 to 6.0 μm.

  In addition, the protective layer 3 is not limited to the structure which consists only of the insulating layer 31 and the conductive layer 32. The structure which further includes the other layer etc. which intervene between the insulating layer 31 and the conductive layer 32 may be sufficient. Further, the protective layer 3 has a configuration in which the composition gradually changes in the thickness direction, so that the portions in contact with the plurality of heat generating portions 211 exhibit insulation and the outer surface 30 exhibits conductivity. Good.

  The conductive layer 32 preferably covers at least the plurality of heat generating portions 211, that is, overlaps with the plurality of heat generating portions 211 in a plan view. Further, in the present embodiment, the conductive layer 32 is formed on the entire surface of the insulating layer 31. As shown in FIG. 6, the insulating layer 31 has an edge 311, and the conductive layer 32 has an edge 321. The edge 311 and the edge 321 extend in the x direction and coincide with each other in plan view. In the present embodiment, the end edge 311 and the end edge 321 have a portion located on the extended portion 231 of the ground connection portion 23.

  The conductive member 4 connects the ground connection portion 23 of the wiring layer 2 and the outer surface 30 of the protective layer 3. The conductive member 4 is not particularly limited as long as it is configured to conduct the ground connection portion 23 of the wiring layer 2 and the outer surface 30 of the protective layer 3, but in the present embodiment, an epoxy that exhibits conductivity by containing Ag. Made of resin. As shown in FIG. 6, in the present embodiment, since the protective layer 3 is composed of the insulating layer 31 and the conductive layer 32, the conductive member 4 is in contact with the insulating layer 31. In addition, the conductive member 4 is in contact with the extending portion 231 of the ground connection portion 23 and is not in contact with the resistor layer 21 constituting the ground connection portion 23. In addition, the conductive member 4 covers each of the edge 311 of the insulating layer 31 and part of the edge 321 of the conductive layer 32.

  In the present embodiment, the conductive member 4 is covered with a protective member 41. The protective member 41 is made of the same material (insulating resin) as the insulating layer generally called a resist layer. The protective member 41 covers at least a part of the protective layer 3. Further, the protection member 41 covers at least a part of the wiring layer 2. Furthermore, in the present embodiment, the protection member 41 covers all the extending portions 231 of the ground connection portion 23.

  The sub-board 6 is provided adjacent to the base material 1 in the y direction and has a long rectangular shape extending long in the x direction. The sub-board 6 has a base material made of glass epoxy resin, for example, and a wiring layer 61 is formed on the base material. In addition, two connectors 63 are attached to the sub-board 6. These connectors 63 are used to connect the thermal print head A1 to a thermal printer.

  As shown in FIGS. 2, 4, and 6, a wire 52 is bonded to the ground connection portion 23. The wire 52 is bonded to a ground line 62 that is a part of the wiring layer 61 of the sub-board 6. The ground line 62 is connected to the ground line of the thermal printer via the connector 63.

  The driver IC 5 controls the heat generation distribution and the heat generation timing in the plurality of heat generating portions 211 by selectively energizing the plurality of heat generating portions 211. As shown in FIG. 1, in the present embodiment, a plurality of driver ICs 5 are arranged near the base material 1 of the sub-board 6. As shown in FIGS. 2 and 3, a plurality of wires 52 are bonded to the plurality of electrodes provided on the upper surface of the driver IC 5. Some of these wires 52 are bonded to a plurality of pad portions connected to the plurality of individual electrodes 221 of the wiring layer 2. Further, the other part of the plurality of wires 52 is appropriately bonded to the wiring layer 61 of the sub-board 6.

  The driver IC 5 is covered with a sealing member 51. The sealing member 51 is, for example, a black insulating resin, and is for protecting the driver IC 5, and covers the driver IC 5 so as to straddle the base material 1 and the sub board 6. As shown in FIGS. 3 and 4, the sealing member 51 covers a part of the protection member 41. The sealing member 51 covers the wire 52 bonded to the ground connection portion 23.

  The heat radiating member 7 is attached to the back surface 12 of the base material 1 and the lower surface of the sub-substrate 6 in the figure via a bonding layer 71. The heat radiating member 7 is for accelerating the heat radiation from the base material 1 and is a block made of a metal such as Al.

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

  First, the base material 1 shown in FIG. 7 is prepared. In addition, FIG. 7 has shown the site | part shown in FIG. The base material 1 is a plate material made of ceramics such as alumina, for example. A glaze layer 13 is formed on the main surface 11 of the substrate 1. The glaze layer 13 is formed by, for example, applying a paste containing a glass component to a predetermined region of the main surface 11 and curing it by firing.

Next, as shown in FIGS. 8 and 9, a resistor layer 21A is formed. In addition, FIG. 9 has shown the site | part shown in FIG. The resistor layer 21A is formed by sputtering using a resistor material such as TaSiO ₂ or TaN. The resistor layer 21A thus formed has a thickness of, for example, about 0.05 μm to 0.2 μm. The resistor layer 21 </ b> A is formed on the entire main surface 11 of the substrate 1.

  Next, as shown in FIGS. 10 and 11, an electrode layer 22A is formed. The electrode layer 22A is formed by sputtering using a metal as a highly conductive material such as Al. The electrode layer 22A formed thereby has a thickness of about 0.5 μm to 2.0 μm, for example. The electrode layer 22A is formed on the entire surface so as to cover the entire resistor layer 21A.

  Next, the resistor layer 21A and the electrode layer 22A are patterned. This patterning is performed, for example, by etching using a mask finely processed into a predetermined shape. As a result, the resistor layer 21A and the electrode layer 22A are patterned into a plan view shape substantially the same as that of the wiring layer 2 shown in FIG. As a result, as shown in FIG. 12, the resistor layer 21 is formed, and the resistor layer 21 and the electrode layer 22A have a configuration in which the above-described ground connection portion 23 is to be formed.

  Next, the electrode layer 22A is selectively patterned. Thereby, as shown in FIG. 13, an electrode layer 22 having a plurality of individual electrodes 221 and a common electrode 222 is formed. Further, by forming the plurality of individual electrodes 221 and the common electrode 222, the resistor layer 21 has a plurality of heat generating portions 211. Further, as shown in FIG. 14, by extending a part of the resistor layer 21 from the electrode layer 22, the ground connection portion 23 having the extending portion 231 is formed.

Next, as shown in FIGS. 15 and 16, an insulating layer 31 is formed. Formation of the insulating layer 31 is performed by sputtering using a glass material typified by SiO _2, for example. At this time, a mask 81 is used to form the insulating layer 31 in a desired region. The mask 81 has an edge extending in the x direction. This end edge is positioned so as to overlap the extended portion 231 of the ground connection portion 23. Thereby, the insulating layer 31 which has the edge 311 which overlaps with the extension part 231 and extends long in the x direction is formed. The thickness of the insulating layer 31 is, for example, about 0.6 μm to 2.0 μm. The insulating layer 31 covers the plurality of heat generating portions 211, the plurality of individual electrodes 221, and the common electrode 222.

  Next, as shown in FIGS. 17 and 18, a conductive layer 32 is formed. The conductive layer 32 is formed by sputtering using a conductive material typified by C / SiC, SiN, or SiALON, for example. At this time, the mask 81 described above is used as it is. Thereby, the conductive layer 32 is formed in the same region as the insulating layer 31. The conductive layer 32 has an edge 321 that coincides with the edge 311 in a plan view. The thickness of the conductive layer 32 is, for example, about 4.0 to 6.0 μm.

  Next, as shown in FIG. 19, the conductive member 4 is formed. The conductive member 4 is formed, for example, by applying an epoxy resin material containing Ag at a relatively high concentration and curing it. In the application, the epoxy resin material is straddled across the edge 311 of the insulating layer 31 and the edge 321 of the conductive layer 32. Then, the conductive member 4 is brought into contact with the outer surface 30 of the insulating layer 31 (protective layer 3) and the extending portion 231 of the ground connection portion 23. The conductive member 4 is not brought into contact with the resistor layer 21 constituting the ground connection portion 23.

  Next, as shown in FIG. 20, a protective member 41 is formed. The protective member 41 is formed by covering the conductive member 4 with an insulating resin material that forms a layer generally referred to as a resist layer. In the present embodiment, the protection member 41 covers a part of the insulating layer 31, the whole ground connection part 23, and a part of the resistor layer 21 constituting the ground connection part 23.

  Next, as shown in FIG. 21, the heat radiating member 7 is bonded to the back surface 12 of the substrate 1 via the bonding layer 71. At this time, the sub-board 6 is attached to the heat dissipation member 7 via the bonding layer 71. Thereafter, the above-described thermal print head A1 is obtained by mounting the driver IC 5 on the sub-board 6, bonding a plurality of wires 52, and forming the sealing member 51.

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

  According to this embodiment, the outer surface 30 of the protective layer 3 is made of a conductive material, and the outer surface 30 is grounded. Thereby, even when the protective layer 3 and the thermal paper are continuously rubbed when the thermal print head A1 is used, static electricity generated by this is discharged from the outer surface 30 of the protective layer 3 by ground connection. . Therefore, it is possible to prevent excessive static electricity from being charged in the protective layer 3, and to suppress electrostatic breakdown of the thermal print head A1.

  Since the wiring layer 2 formed on the main surface 11 of the substrate 1 has the ground connection portion 23, the means for connecting the outer surface 30 of the protective layer 3 and the ground connection portion 23 conducts an unreasonably long distance. Can be avoided.

  By providing the conductive member 4, the outer surface 30 of the protective layer 3 and the ground connection portion 23 can be reliably conducted.

  Since the protective layer 3 includes the insulating layer 31 and the conductive layer 32, the plurality of heat generating portions 211 are reliably insulated by the insulating layer 31, and the outer surface 30 of the protective layer 3 is conductive by the conductive layer 32. Can be reliably maintained.

  Since the conductive layer 32 covers the plurality of heat generating portions 211, the conductive layer 32 can be positioned at a portion to which the thermal paper or the like is pressed. Thereby, discharge of static electricity can be performed more effectively. The formation of the conductive layer 32 over the entire surface of the protective layer 3 is suitable for promoting discharge of static electricity.

  By bringing the conductive member 4 into contact with the extending portion 231 of the ground connection portion 23, it is possible to prevent the conductive member 4 from being peeled as compared with the case where the conductive member 4 and the resistor layer 21 are in contact with each other.

  By providing the protective member 41, peeling of the conductive member 4 can be suppressed. Further, the protective member 41 covers all of the extended portions 231 of the ground connection portion 23 and a part of the resistor layer 21 constituting the ground connection portion 23, thereby further ensuring the prevention of peeling of the conductive member 4. Can do.

  22 to 30 show another embodiment of the present invention. In these drawings, the same or similar elements as those in the above embodiment are denoted by the same reference numerals as those in the above embodiment.

  FIG. 22 shows a thermal print head according to the second embodiment of the present invention. In the thermal print head A <b> 2 of the present embodiment, the wiring layer 2 has two ground connection portions 23. These ground connection portions 23 are arranged apart from both ends of the base material 1 in the x direction. Each ground connection portion 23 is configured as shown in FIG. 6, and is electrically connected to the outer surface 30 (conductive layer 32) of the protective layer 3 through the conductive member 4.

  Such an embodiment can also suppress the electrostatic breakdown of the thermal print head A2. In addition, the protective layer 3 is configured to be grounded at two locations near the both ends in the x direction of the substrate 1. Thereby, discharge of static electricity can be further promoted.

  23 and 24 show a thermal print head according to a third embodiment of the present invention. In the thermal print head A3 of the present embodiment, the wiring layer 2 has three ground connection portions 23. Two ground connection portions 23 are disposed near both ends of the base material 1 in the x direction, and the remaining one ground connection portion 23 is disposed near the center of the base material 1 in the x direction. As clearly shown in FIG. 24, one ground connection portion 23 is disposed between two driver ICs 5 adjacent in the x direction. Each ground connection portion 23 is configured as shown in FIG. 6, and is electrically connected to the outer surface 30 (conductive layer 32) of the protective layer 3 through the conductive member 4.

  Such an embodiment can also suppress the electrostatic breakdown of the thermal print head A3. The protective layer 3 is grounded at a location near the center of the base 1 in the x direction. Thereby, for example, when the thermal print head A3 has a relatively long length in the x direction, it can be expected to discharge static electricity more reliably.

  FIG. 25 shows a thermal print head according to the fourth embodiment of the present invention. The thermal print head A4 of this embodiment is different from the above-described thermal print heads A1 to A3 in the configuration for connecting the outer surface 30 of the protective layer 3 to the ground. In addition, you may employ | adopt suitably the structure which applied the conduction | electrical_connection form with the outer surface 30 of the protective layer 3 in this embodiment to the ground connection part 23 made into arrangement | positioning shown to thermal print head A1-A3.

  In the present embodiment, an opening 312 is formed in the insulating layer 31. The opening 312 is a through hole provided in the insulating layer 31. The conductive layer 32 and the extending portion 231 of the ground connection portion 23 are in contact with each other through the opening 312. This is a configuration for grounding the outer surface 30 of the protective layer 3 in the present embodiment. Further, in relation to the manufacturing method described later, the edge 311 of the insulating layer 31 and the edge 321 of the conductive layer 32 do not necessarily match in plan view. In the present embodiment, the insulating layer 31 covers a part of the resistor layer 21 constituting the ground connection portion 23.

  Next, an example of a manufacturing method of the thermal print head A4 will be described below with reference to FIGS.

  The insulating layer 31A shown in FIG. 26 is formed by performing the same processing as the manufacturing method of the thermal print head A1 described above with reference to FIGS. Next, an opening 312 shown in FIG. 27 is formed by a technique such as etching. Then, as shown in FIG. 28, the conductive layer 32 is formed by a technique such as sputtering. Since the mask used when forming the insulating layer 31A is different from the mask used when forming the conductive layer 32, the edge 311 of the insulating layer 31 and the edge 321 of the conductive layer 32 are not necessarily identical in plan view. I have not done it.

  Also according to such an embodiment, electrostatic breakdown of the thermal print head A4 can be suppressed.

  29 and 30 show a thermal print head according to a fifth embodiment of the present invention. The thermal print head A5 of this embodiment is different from the thermal print heads A1 to A4 described above in the mounting form of the driver IC5. The configuration other than the mounting form of the driver IC 5 can be applied to the thermal print head A5 by appropriately combining the configurations of the thermal print heads A1 to A4. 29 is a cross-sectional view corresponding to FIG. 3, and FIG. 30 is a cross-sectional view corresponding to FIG.

  In the present embodiment, the driver IC 5 is supported by the base material 1 and is conductively joined to an appropriate place of the wiring layer 2. Such a mounting form is called flip chip mounting. The thermal print head A5 has a flexible wiring board 65. The flexible wiring board 65 includes, for example, a conductor layer 651 and two insulating layers 652 sandwiching the conductor layer 651. The conductor layer 651 of the flexible wiring board 65 is conductively joined to an appropriate place of the wiring layer 2 of the base 1. The flexible wiring board 65 is used for connection with a thermal printer on which the thermal print head A5 is mounted.

  Such an embodiment can also suppress the electrostatic breakdown of the thermal print head A5.

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

A1 thermal print head A2 thermal print head A3 thermal print head A4 thermal print head A5 thermal print head 1 base material 11 main surface 12 back surface 13 glaze layer 2 wiring layer 21 resistor layer 211 heating part 22 electrode layer 221 individual electrode 222 common electrode 223 Comb portion 224 Detour portion 23 Ground connection portion 231 Extension portion 3 Protective layer 30 Outer surface 31 Insulating layer 311 Edge 312 Opening 32 Conductive layer 321 Edge 4 Conductive member 41 Protective member 5 Driver IC
51 sealing member 52 wire 6 sub-board 61 wiring layer 62 ground line 63 connector 7 heat dissipation member 71 bonding layer 65 flexible wiring board 651 conductor layer 652 insulating layer 81 mask 21A resistor layer 22A electrode layer 31A insulating layer

Claims (48)

A substrate;
A plurality of heat generating parts supported by the base material and arranged in the main scanning direction;
A protective layer covering the plurality of heat generating parts;
A thermal print head comprising:
The protective layer is made of an insulating material at a portion in contact with the plurality of heat generating portions, and at least a part of an outer surface located on the side opposite to the plurality of heat generating portions in the thickness direction is made of a conductive material,
A portion of the protective layer made of the conductive material is ground-connected.   The thermal print head of Claim 1 provided with the wiring layer which has the ground connection part which should be supported by the said base material and should be ground-connected.   The thermal print head of Claim 2 provided with the electrically-conductive member which connects the said ground connection part of the said wiring layer, and the said outer surface of the said protective layer.   The thermal print head according to claim 3, wherein the conductive member contains Ag.   The thermal layer according to claim 3 or 4, wherein the protective layer includes an insulating layer made of an insulating material in contact with the plurality of heat generating portions, and a conductive layer made of a conductive material formed on the insulating layer. Print head.   The thermal print head according to claim 5, wherein the conductive layer covers the plurality of heat generating portions.   The thermal print head according to claim 5, wherein the conductive layer is formed over the entire surface of the protective layer.   8. The thermal print head according to claim 5, wherein each of the insulating layer and the conductive layer is covered with the conductive member and has an edge that coincides in plan view.   The thermal print head according to claim 5, wherein the conductive layer is thicker than the insulating layer. The thermal print head according to claim 5, wherein the insulating layer is made of SiO ₂ .   The thermal print head according to claim 5, wherein the conductive layer is made of C / SiC, SiN, or SiALON.   The thermal print head according to any one of claims 3 to 11, wherein the wiring layer has a lower layer located on the substrate side and an upper layer formed on the lower layer.   The thermal print head according to claim 12, wherein the conductive member is in contact with an extension portion extending from the upper layer of the lower layer of the ground connection portion.   The thermal print head of Claim 13 provided with the protection member which covers the said electrically-conductive member.   The thermal print head according to claim 14, wherein the protective member covers at least a part of the protective layer.   The thermal print head according to claim 14, wherein the protection member covers at least a part of the wiring layer.   The thermal print head according to any one of claims 14 to 16, wherein the protection member covers all of the extension portions of the lower layer of the wiring layer.   The thermal print head according to claim 14, wherein the protective member covers at least a part of the upper layer of the wiring layer. The protective layer includes an insulating layer made of an insulating material in contact with the plurality of heat generating portions, and a conductive layer made of a conductive material formed on the insulating layer, and at least a part of the ground connection portion Covering
The thermal print head according to claim 2, wherein the conductive layer is in contact with the ground connection portion.   The thermal print head according to claim 19, wherein the conductive layer covers the plurality of heat generating portions.   The thermal print head according to claim 19 or 20, wherein the conductive layer is formed over the entire surface of the protective layer.   The thermal print head according to any one of claims 19 to 21, wherein the insulating layer covers at least a part of the ground connection portion and has an opening for contacting the conductive layer with the ground connection portion.   The thermal print head according to any one of claims 19 to 22, wherein each of the insulating layer and the conductive layer has edges that do not coincide with each other in a plan view.   The thermal print head according to claim 19, wherein the conductive layer is thicker than the insulating layer. The thermal print head according to claim 19, wherein the insulating layer is made of SiO ₂ .   26. The thermal print head according to claim 19, wherein the conductive layer is made of C / SiC, SiN, or SiALON.   27. The thermal print head according to claim 19, wherein the wiring layer has a lower layer located on the substrate side and an upper layer formed on the lower layer.   28. The thermal print head according to claim 27, wherein the conductive layer is in contact with an extension portion extending from the upper layer of the lower layer of the ground connection portion.   The thermal print head according to claim 28, further comprising a protective member that covers the conductive member.   30. The thermal print head according to claim 29, wherein the protective member covers at least a part of the protective layer.   The thermal print head according to claim 29 or 30, wherein the protection member covers at least a part of the wiring layer.   32. The thermal print head according to claim 29, wherein the protection member covers all of the extension portions of the lower layer of the wiring layer.   33. The thermal print head according to claim 29, wherein the protection member covers at least a part of the upper layer of the wiring layer.   The thermal print head according to any one of claims 12 to 18 and 27 to 33, wherein the lower layer of the wiring layer is a resistor layer having portions constituting the plurality of heat generating portions. The thermal print head according to claim 34, wherein the resistor layer is made of TaSiO ₂ or TaN.   36. The thermal print head according to any one of claims 12 to 18 and 27 to 35, wherein the upper layer is an electrode layer made of a material having an electric resistance smaller than that of the resistor layer.   The thermal print head according to claim 36, wherein the electrode layer is made of Al.   38. The thermal print head according to claim 36, wherein the electrode layer has a plurality of individual electrodes each extending to the plurality of heat generating portions.   39. The thermal print head according to claim 38, wherein the electrode layer has a common electrode including a plurality of comb-tooth portions disposed to face the individual electrodes with the plurality of heat generating portions interposed therebetween in the sub-scanning direction. A sub-board disposed adjacent to the base material in the sub-scanning direction;
40. The thermal print head according to claim 2, further comprising: a driver IC mounted on the sub-board and controlling heat generation at the plurality of heat generating portions.   41. The thermal print head according to claim 40, further comprising a sealing member that seals the driver IC. The sub-board has a ground line,
42. The thermal print head according to claim 40, wherein the ground connection portion and the ground line are connected via a wire.   43. The thermal print head according to claim 42, wherein the sealing member seals the wire.   40. The thermal print head according to claim 2, further comprising a driver IC that is supported by the base material and controls heat generation at the plurality of heat generating portions.   45. The thermal print head according to claim 44, wherein the driver IC is flip-chip mounted on the wiring layer.   46. The thermal print head according to claim 44, comprising a flexible wiring board connected to the wiring layer.   The thermal print head according to any one of claims 1 to 46, further comprising a heat dissipation member bonded to the base opposite to the plurality of heat generating portions.   48. The thermal print head according to claim 1, wherein the base material is made of ceramics.

Images