JP2008168579A - Thermal head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal head which can prevent the poor connection between a discrete electrode and a driver IC and the delamination between layers of a head part. <P>SOLUTION: In the thermal head 40, the surface part containing a terminal area 34a of the discrete electrode 44a is formed with a terminal joining layer 34 made of gold or a gold alloy, and thereby, a good joining face wherein a surface oxidation and corrosion of the terminal area 34a is prevented is obtained, and also a good electrical connection with a flexible wiring board 53 in a low contact resistance is assured. A good adhesion between the terminal tie layer 34 and a protective layer 45 is assured by forming an adhesion layer 35 for the protective layer 45 in the surface part other than the terminal area 34a of the terminal tie layer 34, and then the head part free from the delamination between layers and excellent in reliability can be obtained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thermal head used for a thermal printer or the like.

  In general, a thermal head mounted on a thermal printer such as a thermal printer or a thermal transfer printer has a plurality of heating resistors arranged linearly on an insulating substrate, and selectively selects each heating resistor according to printing and printing information. Electric heating is performed. In a thermal printer, color recording is performed on thermal recording paper, and in a thermal transfer printer, ink on the ink ribbon is melted or sublimated and transferred and recorded on plain paper.

  11 to 13 show an example of the configuration of a conventional thermal head. FIG. 11 is a schematic plan view of the entire head chip, FIG. 12 is an enlarged view of portion A in FIG. 11, and FIG. 13 is a conventional thermal head. FIG.

A glaze layer 12 having a circular arc shape made of a glass material functioning as a heat storage layer is laminated on an upper surface of an insulating substrate 11 such as alumina. On the upper surface of the glaze layer 12, a plurality of heating resistors 13 made of Ta—SiO ₂ or the like are entirely laminated by vapor deposition, sputtering, etc., and then aligned linearly by etching using a photolithography technique. Is formed. An individual electrode 14 and a common electrode 15 for energizing each heating resistor 13 are formed on the upper surfaces on both sides of each heating resistor 13.

  The individual electrode 14 is generally made of aluminum or an aluminum alloy, and is formed on the substrate 11 by vapor deposition or sputtering to a thickness of about 0.3 μm to 3 μm. It is patterned into a predetermined shape by the etching process used. Each heating resistor 13 is independently formed so as to be exposed between the individual electrode 14 and the common electrode 15. The heating resistor 13 generates heat when a voltage is applied between the electrodes 14 and 15.

  A protective layer 16 having a thickness of about 3 μm to 10 μm is laminated on the insulating substrate 11, the glaze layer 12, the heating resistor 13, a part of the individual electrode 14, and the upper surface of the common electrode 15. This protective layer 16 is formed for the purpose of protecting the heating resistors 13 and the electrodes 14 and 15 from the oxidation of the heating resistors 13 and the electrodes, and the abrasion caused by contact with the ink ribbon and the damage caused when foreign matter is mixed. . The protective layer 16 is formed by a technique such as mask sputtering.

  The individual electrode 14 is electrically connected to a driver IC 17 made of a semiconductor chip. The driver IC 17 has a built-in switching element that controls energization for each individual electrode 14, and is configured to individually supply power to each heating resistor 13 to generate heat based on print data.

  A wire bonding method is widely used for electrical connection between the individual electrode 14 and the driver IC 17 (see, for example, Patent Document 1 below). As shown in FIG. 13, the driver IC 17 is mounted on the wiring board 18 in a face-up manner, and electrode pads arranged on the active surface are protected by gold wires (bonding wires) 19a and 19b. 16 are connected to the terminal region 14 a of the individual electrode 14 exposed from the terminal 16 and the terminal portion (land) on the wiring board 18. The wiring board 18 is joined to the heat sink 20 together with the insulating board 11.

  In the conventional thermal head, since the individual electrode is formed of aluminum or an alloy thereof, as shown in FIG. 13 in order to prevent surface oxidation of the terminal region 14a of the individual electrode 14 not covered with the protective layer 16. In addition, the terminal region 14a is molded with the sealing resin 21 together with the driver IC and the bonding wires 19a and 19b. In this case, the thickness of the sealing resin 21 is increased, and a guide plate 22 that guides the running of the paper or ink ribbon is provided on the top of the sealing resin 21 in order to prevent interference with the paper or ink ribbon on the head surface. There was a need.

  In the conventional thermal head having such a configuration, the sealing process of the terminal region 14a and the installation process of the guide plate 22 are necessary, which increases the number of work steps and impairs the productivity.

  On the other hand, the one using a flexible wiring board for electrical connection of the thermal head is also known. For example, Patent Document 2 below discloses a configuration in which a driver IC and a connector connected to a control unit of a printer device are connected by a flexible wiring board. Here, it is conceivable to use a flexible wiring board for electrical connection between the individual electrodes of the thermal head and the driver IC. FIG. 14 shows a configuration in which the individual electrodes 14 and the driver IC 17 and the driver IC and the wiring board 18 are connected via flexible wiring boards 23a and 23b, respectively.

  As described above, in the electrical connection using the flexible wiring board, the driver IC mounting portion can be formed thinner than in the case of using wire bonding, so that there is no possibility of interference with the paper or ink ribbon on the upper surface of the head. Installation of the plate 22 (FIG. 13) becomes unnecessary. Further, when the anisotropic conductive material 24 is used for joining the flexible wiring boards 23 a and 23 b to the individual electrodes 14, the driver IC 17, and the wiring board 18, the anisotropic conductive material particularly in the connection portion with the individual electrodes 14. 24 functions as a surface protective layer of the terminal region 14a, and there is an advantage that corrosion of the individual electrode 14 can be prevented.

JP 2005-280203 A JP 2005-238663 A

  In general, in a terminal bonding structure using a flexible wiring board, adhesion between terminals to be bonded is important. In particular, when the flexible wiring board 23a is joined to the individual electrode 14 (terminal region 14a) made of an aluminum-based metal, if there is an oxide layer or corrosion on the surface of the terminal region 14a, joint failure or electrical connection failure is likely to occur. There's a problem.

  On the other hand, gold or a gold alloy in which nickel or cobalt is added to gold is known as a material that is difficult to oxidize and has a low electrical resistance. It is conceivable to prevent the occurrence of poor electrical connection.

  However, gold or gold alloy generally has poor adhesion to oxides and nitrides. In the conventional thermal head described above, the individual electrode 14 is formed on the heat generating resistor 13 or the insulating base material 11 such as glass, and the protective layer 16 is provided on the individual electrode 14. Since the heating resistor 13, the insulating substrate 11, and the protective layer 16 are often formed of an oxide or nitride, when the individual electrode 14 is formed of gold or a gold alloy, delamination occurs at the head portion. There is a problem that arises.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a thermal head that can prevent poor connection between the individual electrodes and the driver IC and delamination of the head portion.

  In solving the above-described problems, the thermal head of the present invention includes an insulating substrate, a heat storage layer formed on the surface of the substrate, a heating resistor formed on the heat storage layer, and a heating resistor. The individual electrode and the common electrode formed on the heat storage layer, the heating resistor, a part of the individual electrode and the protective layer covering the common electrode, and the terminal area of the individual electrode exposed from the protective layer are electrically connected to generate heat. In a thermal head including a driver IC that controls energization of a resistor, a surface portion including at least a terminal region of an individual electrode is formed of a terminal bonding layer made of gold or a gold alloy, and this terminal bonding layer An adhesion layer for the protective layer is formed on the surface portion other than the terminal region.

  In the thermal head of the present invention, since the surface portion including at least the terminal region of the individual electrode is formed of a terminal bonding layer made of gold or a gold alloy, a good bonding surface in which surface oxidation or corrosion of the terminal region is prevented In addition, it is possible to ensure a good electrical connection with a low contact resistance with a terminal member such as a flexible wiring board.

  In the thermal head of the present invention, since the adhesion layer for the protective layer is formed on the surface portion other than the terminal region of the terminal bonding layer, good adhesion between the terminal bonding layer and the protective layer is ensured. In addition, it is possible to configure a highly reliable head portion without delamination.

  The configuration of the individual electrode is not particularly limited as long as the surface portion including at least the terminal region of the individual electrode is formed by the terminal bonding layer. Specifically, in the present invention, the terminal bonding layer is connected to the end of the electrode layer made of aluminum or an aluminum alloy in the individual electrode.

  The adhesion layer can be composed of a titanium layer, a chromium layer, a tantalum layer, or an alloy layer thereof. Since the adhesion layer is not formed in the terminal region of the individual electrode, the electrical connection reliability is not impaired. In addition, when the individual electrodes are configured as described above, by forming an adhesion underlayer between the terminal bonding layer and the heating resistor or the substrate, the terminal bonding layer and the heating resistor layer or the substrate are formed. Interlayer delamination can be prevented. The underlayer can be composed of a titanium layer, a chromium layer, a tantalum layer, or an alloy layer thereof.

  In the present invention, the individual electrode may have a configuration in which the terminal bonding layer is laminated on an electrode layer made of aluminum or an aluminum alloy. In addition to this, the entire individual electrode may be formed of the terminal bonding layer. Examples of the gold alloy constituting the terminal bonding layer include an Au—Ni alloy and an Au—Co alloy. In addition, as an aluminum alloy which comprises an electrode layer, Al-Si alloy, Al-Mg alloy, Al-Cu alloy etc. are mentioned, for example.

  The terminal member joined to the terminal region of the individual electrode is preferably a flexible wiring board. In particular, the resistance of the junction structure can be reduced by using a flexible wiring board whose surface is plated with gold. Moreover, you may perform joining between these individual electrodes and a flexible wiring board using an anisotropic conductive material.

  As described above, according to the thermal head of the present invention, it is possible to obtain a good joint surface in which the surface oxidation or corrosion of the terminal region of the individual electrode is prevented, and to reduce the contact with a terminal member such as a flexible wiring board. Good electrical connection with contact resistance can be ensured. In addition, good adhesion between the terminal bonding layer and the protective layer can be ensured, and a head part having excellent reliability without delamination can be obtained.

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

  FIG. 1 is a schematic configuration diagram of a printer device 30 including a thermal head according to an embodiment of the present invention, and FIG. 2 is a cross-sectional perspective view of a main part of the printer device 30. Hereinafter, the configuration of the printer device 30 will be schematically described.

  The printer device 30 is a thermal transfer type or sublimation type printer device, and includes a thermal head 40 according to the present invention. The thermal head 40 sublimates the color material of the ink ribbon 1 to the print medium 2 such as paper. Color images and characters are printed by transferring

  The ink ribbon 1 used here is made of a long resin film, one end is supported by the supply-side spool 3a and the other end is supported by the winding-side spool 3b, and the ink cartridge ( (Not shown). The ink ribbon 1 includes an ink layer formed of a yellow color material, an ink layer formed of a magenta color material, and an ink layer formed of a cyan color material on one surface of a resin film. In order to improve the storability of images and characters printed on the print medium 2, a laminate layer made of a laminate film that is thermally transferred onto the print medium 2 is provided.

  The printer device 30 includes a thermal head 40, a platen 60 provided at a position facing the thermal head 40, a plurality of ribbon guides 61 a and 61 b that guide the travel of the mounted ink ribbon 1, and the ink ribbon 1. Between the thermal head 40 and the platen 60, there are provided a pinch roller 62a and a capstan roller 62b for running the printing medium 2.

  In the printer device 30 having such a configuration, the ink ribbon 1 is rotated by rotating the winding side spool 3b in the winding direction between the thermal head 40 and the platen 60 while pressing the platen 60 against the thermal head 40. And the pinch roller 62a and the capstan roller 62b are rotated in the paper discharge direction (arrow A direction in FIG. 1), and the print medium 2 is moved in the paper discharge direction.

  When printing, first, thermal energy is applied from the thermal head 40 to the yellow ink layer of the ink ribbon 1, and the yellow color material is thermally transferred to the printing medium 2 that runs while overlapping the ink ribbon 1. . Next, in order to thermally transfer the magenta color material to the image forming portion for forming the image or characters on which the yellow color material is thermally transferred, the print medium 2 is moved backward toward the thermal head 40 in the direction of arrow B in FIG. The starting end of the image forming unit is opposed to the thermal head 40, and the magenta ink layer of the ink ribbon 1 is opposed to the thermal head 40. Then, thermal energy is also applied to the magenta ink layer to thermally transfer the magenta color material to the image forming portion of the print medium 2. The cyan color material and the laminate film are also sequentially heat-transferred to the printing medium 2 by the same method to form a color image.

  The thermal head 40 used in such a printer device 30 is arranged in a direction orthogonal to the traveling direction of the print medium 2, so that the color material can be thermally transferred to both ends in the width direction of the print medium 2. The length shown in the middle arrow L direction is longer than the width of the print medium 2.

Next, details of the configuration of the thermal head 40 will be described.
FIG. 3 is an overall perspective view of the thermal head 40, and FIG. 4 is a partially broken perspective view showing a cross-sectional structure of the head portion 40 </ b> A of the thermal head 40. FIG. 5 is a side view of the thermal head 40.

  The thermal head 40 has a substrate 41 bonded on a radiator 47 via an adhesive material layer 46, and a head portion 40 </ b> A is formed along the length direction L at the center portion in the width direction of the substrate 41. Has been. The head portion 40A has a substantially arcuate outer shape, and heat generating portions 43a are linearly arranged at a predetermined pitch in the length direction L at the top. The head portion 40A is formed so as to protrude outward from the substrate 41, so that the head ribbon 40A can make good contact with the ink ribbon 1, and heat energy generated by the heat generating portion 43a can be appropriately applied to the ink ribbon 1. The surface of the head portion 40A is covered with a protective layer 45.

  The heat generating portion 43a has a configuration sandwiched between a pair of electrodes 44a and 44b, and generates heat by a resistance heating action when a current is supplied between the electrodes 44a and 44b. One electrode 44 a constitutes an individual electrode connected to the individual wiring portion 52 formed for each heat generating portion 43 a and is electrically connected to the control board 55 via the flexible wiring board 53. . The other electrode 44b constitutes a common electrode connected to the common wiring portion 51 that is common to all the heat generating portions 43a, and is electrically connected to the control board 55 via the flexible wiring board 54. ing.

  The control board 55 is fixed to the heat radiating body 47 and is connected to a control unit (not shown) of the printer device 30 via an external connection wiring member 56. A driver IC 57 made of a semiconductor element is mounted on the flexible wiring board 53 (FIG. 5). The driver IC 57 individually performs the heat generation operation of each heat generating portion 43a in accordance with the print data sent from the control board 55. Built-in switching element to control.

  Hereinafter, details of the head unit 40A will be described. FIG. 6 is a cross-sectional view showing details of the configuration of the thermal head 40.

  On one surface (front surface) of the substrate 41, a glaze layer 42 is integrally formed as a heat storage layer whose outer surface has a substantially arc shape. The substrate 41 is made of a general vitreous material such as borosilicate glass. On the glaze layer 42, a heating resistor 43, an individual electrode 44a and a common electrode 44b for energizing the heating resistor 43, and a protective layer for protecting the heating resistor 43, the individual electrode 44a and the common electrode 44b. 45 are sequentially stacked.

The heating resistor 43 is made of a material having high resistance and heat resistance such as Ta—N or Ta—SiO ₂ , for example. An exposed region of the heating resistor 43 sandwiched between the pair of electrodes 44a and 44b is configured as a heating portion 43a, and is formed to have a substantially rectangular or square shape, for example, slightly larger than the pixel size (dot size). . The heating resistor 43 is divided into a plurality of parts on the surface of the substrate 41 by etching using a photolithography technique.

  The individual electrode 44 a is configured by an electrode layer 33 made of aluminum or an alloy thereof formed on the heating resistor 43, and a terminal bonding layer 34 made of gold or a gold alloy connected to the end of the electrode layer 33. Has been. The details of the terminal bonding layer 34 will be described later.

  The common electrode 44b includes an electrode layer 31 made of aluminum or an alloy thereof formed on the heating resistor 43 and a common wiring layer made of, for example, copper or a copper alloy that connects the electrode layers 31 of the heating resistors 43 to each other. It has 32 laminated structures.

  The protective layer 45 covers the heat generating portion 43a, the non-terminal region 34b of the individual electrode 44a, and the common electrode 44b. In particular, the protective layer 45 is formed for the purpose of preventing the heat generating portion 43a and the electrode layers 31 and 33 from being oxidized and protecting the heat generating portion 43a and the electrodes 44a and 44b from abrasion due to contact with the ink ribbon 1.

  As a material constituting the protective layer 45, an oxide film or a nitride film having excellent mechanical characteristics such as high strength and wear resistance at high temperatures and thermal characteristics such as heat resistance, thermal shock resistance, and thermal conductivity is used. For example, it is formed of silicon carbide, silicon nitride, sialon (trade name) or the like.

  The terminal bonding layer 34 constituting the individual electrode 44 a includes a terminal region 34 a that is not covered with the protective layer 45 and a non-terminal region 34 b that is covered with the protective layer 45. The surface portion of the terminal region 34 a is formed of gold or a gold alloy, which is a constituent material of the terminal bonding layer 34, and is connected to the terminal portion of the flexible wiring board 53. The terminal portion of the flexible wiring board 53 has, for example, a structure in which gold or a gold alloy is plated on a copper pattern.

  In the present embodiment, the bonding between the terminal region 34 a and the flexible wiring board 53 is performed via the anisotropic conductive material 58. This anisotropic conductive material 58 is formed by mixing conductive fine particles whose surface is plated with gold in a thermosetting insulating resin, and develops conductivity in the pressure direction, and is a direction orthogonal to the pressure direction. Is a functional material that maintains electrical insulation. The flexible wiring substrate 53 is bonded to the terminal region 34a by heat-curing the anisotropic conductive material 58 in a state where it is pressed against the terminal region 34a with a predetermined bonding pressure. Examples of the anisotropic conductive material 58 include anisotropic conductive pastes as well as anisotropic conductive films.

  Next, the peripheral structure of the non-terminal region 34b of the terminal bonding layer 34 will be described. FIG. 7 is an enlarged view of a main part of the individual electrode 44b.

  An adhesion layer 35 is provided at the interface between the terminal bonding layer 34 and the protective layer 45 to increase the adhesion between the terminal bonding layer 34 and the protective layer 45. As described above, the terminal bonding layer 34 is made of gold or a gold alloy, and when the protective layer 45 made of an oxide or a nitride is directly formed on the terminal bonding layer 34, these adhesive strengths are weak. May cause delamination. Therefore, in the present embodiment, the adhesion layer 35 to the protective layer 45 is formed on the surface of the non-terminal region 34b, thereby increasing the adhesion between the terminal bonding layer 34 and the protective layer 45 to prevent delamination and A highly reliable head portion is configured.

As a material constituting the adhesion layer 34, titanium (Ti), chromium (Cr), tantalum (Ta), or an alloy thereof is used. The film thickness of the adhesion layer 34 is not particularly limited, and is 2 to 20 nm, for example. The adhesion layer 34 is formed only in the non-terminal region 34b of the terminal bonding layer 34 and is not formed in the terminal region 34a. As a specific method for manufacturing the terminal region 34 a, the adhesion layer 35 is formed over the entire surface of the terminal bonding layer 34, and then the protective layer 45 is patterned. Thereafter, the adhesive layer 35 remaining on the terminal region 34a is removed by etching using the protective layer 45 as a mask. As an etching method, when the adhesion layer 35 is titanium, a reactive ion etching (RIE) method using CF ₄ gas plasma is used. Note that the etching method is not limited to RIE, and an ion beam etching method, a wet etching method, or the like is applicable.

  On the other hand, a base layer 36 is provided at the interface between the terminal bonding layer 34 and the heating resistor 43 to increase the adhesion between the terminal bonding layer 34 and the heating resistor 43. That is, when the terminal bonding layer 34 made of gold or a gold alloy is directly formed on the heating resistor 43 made of oxide or nitride, there is a possibility that delamination occurs due to their weak adhesion. Therefore, in this embodiment, by forming an adhesion underlayer 36 at the interface between the terminal bonding layer 34 and the heating resistor 43, the adhesion between the terminal bonding layer 34 and the heating resistor 43 is increased, and delamination is performed. Therefore, a highly reliable head portion is configured.

  As the material constituting the underlayer 36, the same kind of material as that of the adhesion layer 35 can be used. For example, titanium, chromium, tantalum, or an alloy thereof can be preferably used. The film thickness of the underlayer 36 is not particularly limited, and is 2 to 20 nm, for example.

  Depending on the processing shape of the terminal bonding layer 34, a part of the terminal bonding layer 34 may come into contact with the surface of the substrate 41. In this case, delamination between the terminal bonding layer 34 and the substrate 41 is prevented by forming the base layer 36 so as to cover the contact region between the terminal bonding layer 34 and the substrate 41.

  In the thermal head 40 of the present embodiment configured as described above, since the surface portion including at least the terminal region 34a of the individual electrode 44a is formed by the terminal bonding layer 34 made of gold or a gold alloy, the terminal region 34a It is possible to obtain a good joint surface in which surface oxidation and corrosion of the steel are prevented. Moreover, since resistance reduction of a junction part with the flexible wiring board 53 can be achieved, a favorable electrical connection can be ensured.

  Furthermore, in the thermal head 40 of the present embodiment, an adhesion layer 35 for the protective layer 45 is formed on the surface portion of the non-terminal region 34b of the terminal bonding layer 34, and the terminal bonding layer 34 and the heating resistor 43 (or Since the base layer 36 for adhesion is formed at the interface of the substrate 41), it is possible to ensure good adhesion between the terminal bonding layer 34 and the protective layer 45, and to have excellent reliability without delamination. 40A can be configured.

  Since the flexible wiring board 53 is used for the electrical connection between the individual electrode 44a of the head portion 40A and the driver IC 57, the electrical connection between the individual electrode 44a and the driver IC 57 can be easily performed. Since the height of the joining portion can be kept low, interference with the ink ribbon 1 on the upper surface of the head can be prevented.

  Next, a thermal head 50 according to another embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a side sectional view of the thermal head 50, and FIG. 9 is a plan view of the main part of the thermal head 50. Note that portions corresponding to those in the configuration illustrated in FIG. 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the thermal head 50 of the present embodiment, the individual electrode 44 a is composed of an electrode layer 33 and a terminal bonding layer 37 laminated on the electrode layer 33. The electrode layer 33 is made of aluminum or an aluminum alloy, and the terminal bonding layer 37 is made of gold or a gold alloy. For example, as shown in FIG. 9, the terminal bonding layer 37 is formed with a width larger than the wiring width of the electrode layer 33.

  The terminal bonding layer 37 has a terminal region 37 a that is not covered with the protective layer 45 and a non-terminal region 37 b that is covered with the protective layer 45. The surface portion of the terminal region 37 a is formed of gold or a gold alloy that is a constituent material of the terminal bonding layer 37, and is bonded to the terminal portion of the flexible wiring board 53. The terminal bonding layer 37 covers the surface and side surfaces of the underlying electrode layer 33 in the terminal region 37a. The flexible wiring board 53 is bonded to the terminal region 37a of the individual electrode 44a through the anisotropic conductive material 58.

  An adhesion layer (not shown) is provided at the interface between the terminal bonding layer 37 and the protective layer 45 to increase the adhesion between the terminal bonding layer 37 and the protective layer 45. The adhesion layer corresponds to the adhesion layer 35 described above, and is formed only on the surface portion of the non-terminal region 37b of the terminal bonding layer 37, and is not formed on the surface portion of the terminal region 37a. For this reason, the joining surface which consists of gold | metal | money or a gold alloy of the terminal area | region 37a is maintained.

  In the thermal head 50 of the present embodiment configured as described above, since the surface portion including at least the terminal region 37a of the individual electrode 44a is formed by the terminal bonding layer 37 made of gold or a gold alloy, the terminal region 37a It is possible to obtain a good joint surface in which surface oxidation and corrosion of the steel are prevented. Moreover, since resistance reduction of a junction part with the flexible wiring board 53 can be achieved, a favorable electrical connection can be ensured.

  Furthermore, in the thermal head 50 of the present embodiment, an adhesion layer for the protective layer 45 is formed on the surface portion of the non-terminal region 37 b of the terminal bonding layer 37, so that the gap between the terminal bonding layer 37 and the protective layer 45 is formed. It is possible to ensure a good adhesion and to construct a head part having excellent reliability without delamination.

  In the present embodiment, since the base of the terminal bonding layer 37 is the electrode layer 33, it is not essential to form a base layer for achieving close contact between the terminal bonding layer 37 and the heating resistor 43 or the substrate 41. On the other hand, depending on the size of the contact area between the terminal bonding layer 37 and the heat generating resistor 43 or the substrate 41, an interfacial layer for interfacing them may be interposed at these interfaces to prevent delamination between the layers. Also good.

  The embodiment of the present invention has been described above, but the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

  For example, in the above embodiment, the individual electrode 44a has a composite structure of the electrode layer 33 and the terminal bonding layers 34 and 37, but the entire individual electrode may be formed of a terminal bonding layer, that is, gold or a gold alloy. Since gold has a smaller coefficient of thermal expansion than aluminum, the thermal stress of the head part during heat generation can be reduced, and thermal damage of the head part during so-called emptying can be suppressed.

  Further, the configuration of the thermal head is not limited to the above-described example. For example, as shown in FIG. 10, the present invention is also applied to a so-called air gap structure thermal head in which a gap portion 28 is formed in the glaze layer 42. Is possible. As a result, the heat responsiveness of the heat generating portion can be improved, and the printing speed can be improved.

  Further, the mounting position of the driver IC 57 is not limited to the inner surface side of the flexible wiring board 53 as shown in FIG. 5, but the driver IC is mounted on the wiring board installed on the heat radiator, and the flexible wiring board is mounted. An electrical connection may be made between the terminal region of the individual electrode and the driver IC.

  In the configuration of the thermal head described above, the arrangement form of the individual electrodes and the common electrodes is not limited to the common electrode structure, and for example, a folded electrode structure may be adopted.

1 is a schematic configuration diagram of a printer device including a thermal head according to an embodiment of the present invention. It is a cross-sectional perspective view of the principal part of the printer apparatus shown in FIG. 1 is an overall perspective view of a thermal head according to an embodiment of the present invention. It is a partially broken perspective view which shows the structure of the principal part of the thermal head by embodiment of this invention. It is a side view of the thermal head by the embodiment of the present invention. It is principal part sectional drawing of the thermal head by embodiment of this invention. It is an expanded sectional view of the individual electrode part of the thermal head by the embodiment of the present invention. It is principal part sectional drawing of the thermal head by other embodiment of this invention. It is a principal part top view of the thermal head shown in FIG. It is principal part sectional drawing which shows the modification of the structure of the thermal head by embodiment of this invention. It is a schematic plan view of a conventional thermal head. It is a principal part top view of the conventional thermal head. It is principal part sectional drawing of the conventional thermal head. It is principal part sectional drawing of the other conventional thermal head.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Ink ribbon, 2 ... Print medium, 30 ... Printer apparatus, 33 ... Electrode layer, 34, 37 ... Terminal joining layer, 34a, 37a ... Terminal area | region, 34b, 37b ... Non-terminal area | region, 35 ... Adhesion layer, 36 ... Underlayer, 40, 50 ... thermal head, 40A ... head portion, 41 ... substrate, 42 ... glaze layer, 43 ... heating resistor, 43a ... heating portion, 44a ... individual electrode, 44b ... common electrode, 45 ... protective layer, 47 ... radiator, 53 ... flexible wiring board, 57 ... driver IC, 58 ... anisotropic conductive material, 60 ... platen

Claims (6)

An insulating substrate;
A heat storage layer formed on the surface of the substrate;
A heating resistor formed on the heat storage layer;
An individual electrode and a common electrode formed on the heating resistor;
A protective layer covering the heat storage layer, the heating resistor, a part of the individual electrode and the common electrode;
In a thermal head comprising: a driver IC that is electrically connected to a terminal region of the individual electrode exposed from the protective layer and performs energization control of the heating resistor.
The surface portion including at least the terminal region of the individual electrode is formed of a terminal bonding layer made of gold or a gold alloy,
An adhesion layer for the protective layer is formed on a surface portion of the terminal bonding layer other than the terminal region. The thermal head according to claim 1, wherein the individual electrode is formed by connecting the terminal bonding layer to an end portion of an electrode layer made of aluminum or an aluminum alloy. The thermal head according to claim 2, wherein a base layer for adhesion is formed at an interface between the terminal bonding layer and the heating resistor or the substrate. The thermal head according to claim 1, wherein the individual electrode is formed by laminating the terminal bonding layer on an electrode layer made of aluminum or an aluminum alloy. The thermal head according to claim 1, wherein the terminal region and the driver IC are connected by a flexible wiring board having a terminal surface made of gold or a gold alloy. The thermal head according to claim 6, wherein the terminal area of the individual electrode and the flexible wiring board are joined via an anisotropic conductive material.

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