JP2012061711A - Thermal print head and thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress curving of a heating plate caused by sealing of a driving IC with the use of thermosetting resin.SOLUTION: The thermal print head includes a heat sink 20, the heating plate 30, a holding plate 50, a circuit substrate 60, the driving IC 62 and a sealing body 70. The heating plate 30 has a glaze layer 36, a resistor layer 38 and a conductor layer 40 stacked together on a supporting substrate 34 made of ceramic. The heating plate 30 is placed on a surface of the heat sink 20. The holding plate 50 is made of ceramic, and is arranged with the heating plate 30 in a sub scanning direction 92 on the surface of the heat sink 20. The circuit substrate 60 is fixed on the holding plate 50. The driving IC 62 is placed on the circuit substrate, and is electrically connected to a circuit formed on the circuit substrate 60 and an electrode formed on the heating plate 30. The sealing body 70 is made of the thermosetting resin, covers the driving IC 62, and integrally bonds the heating plate 30, the circuit substrate 60 and the holding plate 50.

Description

  The present invention relates to a thermal print head and a thermal printer using the same.

  The thermal print head is an output device that heats a plurality of heat generating resistors arranged in a heat generating area, and prints and prints characters, figures, and the like on a recording medium by the heat. This thermal print head is widely used in recording devices such as a barcode printer, a digital plate making machine, a photo printer, an imager, and a seal printer.

  A conventional thermal print head and thermal printer will be described with reference to FIGS. FIG. 4 is a perspective view of the thermal print head. FIG. 5 is a sectional view of the thermal print head. FIG. 6 is a schematic plan view of the thermal print head. FIG. 7 is a partial cross-sectional view of the thermal printer.

  The thermal print head 10 includes a heat radiating plate 20, a heat generating plate 30, and a circuit board 60. The heat generating plate 30 and the circuit board 60 are placed adjacent to each other on one surface of the heat radiating plate 20. The heat generating plate 30 is disposed on the downstream side (the discharge side of the recording medium 82) in the sub-scanning direction 92 that is the traveling direction of the recording medium 82. The circuit board 60 is disposed adjacent to the heat generating plate 30 on the upstream side in the sub-scanning direction 92 (the recording medium 82 supply side).

  The heat sink 20 is made of a metal such as aluminum. The heat radiating plate 20 plays a role of releasing the heat of the heat generating plate 30 to the outside of the thermal print head 10.

  The heat generating plate 30 extends in the main scanning direction 91 orthogonal to the sub-scanning direction 92 in parallel with the circuit board 60. The heat generating plate 30 includes an insulating substrate 32, a resistor layer 38, a conductor layer 40, and a protective layer 48.

  The insulating substrate 32 has a support substrate 34 and a glaze layer 36. The support substrate 34 is made of ceramic such as alumina. The glaze layer 36 is made of glass and is laminated on the support substrate 34.

  The resistor layer 38 and the conductor layer 40 are sequentially stacked on the glaze layer 36. The resistor layer 38 and the conductor layer 40 form a plurality of heating resistor portions 42 and a plurality of electrodes 44 on the glaze layer 36. The plurality of heating resistor portions 42 are arranged in the main scanning direction 91 at intervals. As shown in FIG. 5, the portion where the conductor layer 40 is not laminated on the resistor layer 38 becomes the heating resistor portion 42. The electrodes 44 are formed at both ends in the sub-scanning direction 92 of each heating resistor portion 42. The electrode 44 is formed by the conductor layer 40.

  When a voltage is applied between a pair of electrodes 44 formed at both ends of each heating resistor 42, each heating resistor 42 generates heat. The heat generation of each heating resistor 42 is selectively controlled by a drive IC 62 described later. A plurality of heat generating resistor portions 42 are arranged, and a belt-like region becomes a heat generating region 46.

  The protective layer 48 is laminated on the exposed surfaces of the insulating substrate 32, the resistor layer 38, and the conductor layer 40, and forms the outermost surface of the heat generating plate 30. The protective layer 48 plays a role of protecting the plurality of heating resistance portions 42 and the plurality of electrodes 44.

  The circuit board 60 extends in the main scanning direction 91 in parallel with the heat generating plate 30. The circuit board 60 is a printed board such as a glass epoxy board. The circuit board 60 is fixed on the heat sink 20. A drive IC 62 and a connector 64 are mounted on the circuit board 60. The drive IC 62 serves as a control element that selectively generates heat from the plurality of heat generating resistor portions 42. A control signal and power for forming a predetermined heat generation pattern in the heat generation region 46 are input via the connector 64.

  The drive IC 62 and the electrode 44 of the heat generating plate 30 are electrically connected by, for example, a bonding wire 66. The drive IC 62 and the circuit formed on the circuit board 60 are electrically connected by, for example, bonding wires 68. The drive IC 62 and the bonding wires 66 and 68 are sealed with a sealing body 70 made of resin. The sealing body 70 serves to protect the drive IC 62 and prevent disconnection of the bonding wires 66 and 68.

  The thermal printer includes a platen roller 80. The platen roller 80 is made of a material having a predetermined elasticity and is formed in a cylindrical shape. The platen roller 80 is installed so as to be rotatable about an axis 80 a along the main scanning direction 91. The platen roller 80 is installed so that the outer peripheral surface 80 b is in contact with the heat generating region 46.

  When the thermal printer is used, a recording medium 82 such as thermal paper that is colored when heated to a temperature higher than the thermal printing temperature is inserted between the platen roller 80 and the heat generating region 46. The thermal printer rotates the platen roller 80 to move the recording medium 82 in the sub-scanning direction 92 while pressing the recording medium 82 against the heat generating area 46. In addition, the thermal printer prints / prints desired characters / images on the recording medium 82 by changing the heat generation pattern of the heat generating area 46 as the recording medium 82 moves.

JP 2008-23939 A JP-A-8-52890

  As described above, the drive IC 62 and the bonding wires 66 and 68 are sealed with the sealing body 70. For the sealing body 70, a thermosetting resin such as an epoxy resin or a thermoplastic resin such as a silicon resin is used. Generally, a thermosetting resin such as an epoxy resin is harder than a thermoplastic resin such as a silicon resin. For this reason, it is desirable to use a thermosetting resin such as an epoxy resin for the sealing body 70 from the viewpoint of protecting the drive IC 62 and preventing the disconnection of the bonding wires 66 and 68.

  In sealing using a thermosetting resin such as an epoxy resin, first, a thermosetting resin is applied on the heating plate 30 and the circuit board 60 so as to cover the drive IC 62 and the bonding wires 66 and 68. Subsequently, after being cured by heating at about 100 ° C. for several hours, it is cooled.

  The heat generating plate 30 and the circuit board 60 are thermally expanded by heating when the thermosetting resin (sealing body 70) is cured. Therefore, the cured thermosetting resin (sealing body 70) is integrally bonded to the heat generating plate 30 and the circuit board 60 in a thermally expanded state. Thereafter, the heat generating plate 30, the circuit board 60, and the sealing body 70 are thermally contracted by cooling.

  Here, the circuit board 60 is a printed board, for example, a glass epoxy board in which an insulating base material including an epoxy resin is used. Therefore, the thermal expansion coefficient of the circuit board 60 is close to the thermal expansion coefficient of the epoxy resin. On the other hand, in the heat generating plate 30, a glaze layer 36, a resistor layer 38, and a conductor layer 40 are formed in a thin film on a support substrate 34 made of ceramic. Therefore, the thermal expansion coefficient of the heat generating plate 30 is close to that of ceramic.

  Since the epoxy resin has a larger coefficient of thermal expansion than ceramic, the circuit board 60 and the sealing body 70 have a larger coefficient of thermal expansion than the heat generating plate 30. Therefore, the contraction force of the circuit board 60 and the sealing body 70 is applied to the sealing portion of the heat generating plate 30 (the portion of the heat generating plate 30 near the circuit substrate 60), and as shown in FIG. It will be curved. That is, the heat generating plate 30 is curved due to the difference in thermal expansion coefficient between the heat generating plate 30 and the circuit board 60 and the sealing body 70. If it does so, the linearity of the heat_generation | fever area | region 46 formed in the heat generating plate 30 will fall. As a result, the contact between the heat generating area 46 and the platen roller 80 is deteriorated, and the image quality is deteriorated.

  Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to suppress the bending of the heat generating plate caused by the sealing of the drive IC using a thermosetting resin.

  In order to achieve the above object, a thermal print head according to the present invention includes a heat sink made of metal, a support substrate made of ceramic, a glaze layer laminated on the support substrate, and a space between each other on the glaze layer. A plurality of heat generating resistor portions formed side by side in the main scanning direction and a plurality of electrodes electrically connected to the plurality of heat generating resistor portions, and mounted on a part of the surface of the heat sink; A heat generating plate placed on the heat radiating plate and fixed to the heat radiating plate, and placed on a part of the surface of the heat radiating plate on which the heat radiating plate is fixed, side by side with the heat radiating plate in the sub-scanning direction. A holding plate fixed to the circuit board, a circuit board fixed on the holding plate, a circuit mounted on the circuit board or the heating plate, and formed on the circuit board and the heating plate. Electrically connected to the electrode A drive IC was made of a thermosetting resin, to cover the drive IC, the heating plate, characterized by comprising a sealing body which is integrally bonded to the circuit board and the holding plate.

  In order to achieve the above object, a thermal printer according to the present invention includes a heat sink made of metal, a support substrate made of ceramic, a glaze layer laminated on the support substrate, and a space between the glaze layer. A plurality of heating resistor portions formed side by side in the main scanning direction and a plurality of electrodes electrically connected to the plurality of heating resistor portions, and part of the surface of the heat sink A heat generating plate placed and fixed to the heat radiating plate, and made of ceramic, and placed on a part of the surface of the heat radiating plate on which the heat generating plate is fixed side by side with the heat generating plate in the sub-scanning direction. A holding plate fixed to a plate, a circuit board fixed on the holding plate, a circuit mounted on the circuit board or the heating plate, and formed on the circuit board and the heating plate Electrically connected to said electrode A thermal print head comprising a driving IC and a sealing body made of a thermosetting resin, covering the driving IC, and integrally sealing the heating plate, the circuit board, and the holding plate. Features.

  According to the present invention, it is possible to suppress the bending of the heat generating plate caused by sealing the drive IC using a thermosetting resin.

1 is a cross-sectional view of a thermal print head according to a first embodiment of the present invention. It is sectional drawing of the thermal print head which concerns on the 2nd Embodiment of this invention. FIG. 5 is a schematic plan view of a thermal print head according to a second embodiment of the present invention. It is a perspective view of the conventional thermal print head. It is sectional drawing of the conventional thermal print head. It is a schematic plan view of a conventional thermal print head. It is a fragmentary sectional view of the conventional thermal printer.

[First Embodiment]
A thermal print head and a thermal printer according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of a thermal print head. In the following description, the same reference numerals are given to the same or similar components as those of the above-described conventional thermal print head and thermal printer, and the description of the components is omitted.

  The thermal print head 10 according to the present embodiment includes a heat radiating plate 20, a heat generating plate 30, a holding plate 50, a circuit board 60, a driving IC 62, and a sealing body 70.

  The heat sink 20 is made of a metal such as aluminum. In the present embodiment, a step is formed along the main scanning direction 91 on one surface of the heat radiating plate 20, and the discharge side of the recording medium 82 of the heat radiating plate 20 is compared with the supply side of the recording medium 82. Designed to be thin.

  The heat generating plate 30 is placed on the surface of the heat radiating plate 20 where the steps are formed. The heat generating plate 30 is disposed on the discharge side of the recording medium 82 of the heat radiating plate 20. The heat generating plate 30 extends from the step toward the discharge side of the recording medium 82. The heat generating plate 30 is fixed to the heat radiating plate 20 by, for example, a double-sided tape 54. The heat generating plate 30 includes an insulating substrate 32, a resistor layer 38, a conductor layer 40, and a protective layer 48.

  The insulating substrate 32 has a support substrate 34 and a glaze layer 36. The support substrate 34 is made of ceramic such as alumina. The glaze layer 36 is made of glass and is laminated on the support substrate 34.

  The resistor layer 38 and the conductor layer 40 are sequentially stacked on the glaze layer 36. The resistor layer 38 and the conductor layer 40 form a plurality of heating resistor portions 42 and a plurality of electrodes 44 on the glaze layer 36. The plurality of heating resistor portions 42 are arranged in the main scanning direction 91 at intervals. The electrodes 44 are formed at both ends in the sub-scanning direction 92 of each heating resistor portion 42.

  The protective layer 48 is laminated on the exposed surfaces of the insulating substrate 32, the resistor layer 38, and the conductor layer 40, and forms the outermost surface of the heat generating plate 30. Note that an opening 48 a is formed at a predetermined position of the protective layer 48 in order to connect the bonding wire 66 to the end of the electrode 44 on the supply side of the recording medium 82.

  The holding plate 50 is made of ceramic such as alumina. The holding plate 50 is placed on the surface of the heat radiating plate 20 where the step is formed. The holding plate 50 is disposed on the discharge side of the recording medium 82 of the heat radiating plate 20. The holding plate 50 extends from the step toward the supply side of the recording medium 82. The holding plate 50 extends in the main scanning direction 91 in parallel with the heat generating plate 30. The holding plate 50 is fixed to the heat radiating plate 20 by, for example, a double-sided tape 55.

  The circuit board 60 is a printed board, for example, an epoxy board or a glass epoxy board using an insulating base material including an epoxy resin. The circuit board 60 is placed on the holding plate 50. The circuit board 60 is fixed to the holding plate 50 by, for example, a double-sided tape 56. In the present embodiment, the circuit board 60 is disposed with a gap 72 in the sub-scanning direction 92 from the heat generating plate 30.

  The plurality of driving ICs 62 are mounted on the circuit board 60. The plurality of driving ICs 62 are arranged at positions near the heat generating plate 30 on the circuit board 60. The plurality of drive ICs 62 are arranged in the main scanning direction 91. The drive IC 62 and the electrode 44 of the heat generating plate 30 are electrically connected by a bonding wire 66. The drive IC 62 and the circuit formed on the circuit board 60 are electrically connected by, for example, bonding wires 68. The drive IC 62 and the bonding wires 66 and 68 are sealed with a sealing body 70.

  The sealing body 70 is made of a thermosetting resin (adhesive) such as an epoxy resin. The sealing body 70 covers the driving IC 62 and the bonding wires 66 and 68. The sealing body 70 is filled in a gap 72 between the heat generating plate 30 and the circuit board 60. The sealing body 70 is adhered to the surface of the heat generating plate 30 near the circuit board 60, the surface of the circuit board 60 close to the heat generating plate 30, and the surface of the holding plate 50 facing the gap 72. The sealing body 70 integrally bonds the heat generating plate 30, the circuit board 60, and the holding plate 50 together.

  For sealing, first, a thermosetting resin is applied on the heating plate 30 and the circuit board 60 so as to cover the drive IC 62 and the bonding wires 66 and 68, and then the thermosetting resin is heated at about 100 ° C. for several hours. And cured.

  The effects of the thermal print head 10 and the thermal printer according to the present embodiment will be described.

  The heat generating plate 30, the circuit board 60, and the sealing body 70 are thermally expanded by heating when the thermosetting resin (sealing body 70) is cured. The cured thermosetting resin (sealing body 70) is integrally bonded to the heat generating plate 30 and the circuit board 60 in a thermally expanded state. Thereafter, the heat generating plate 30, the circuit board 60, and the sealing body 70 are thermally contracted by cooling.

  Here, in the present embodiment, the circuit board 60 is attached to the holding plate 50 made of ceramic by the double-sided tape 56. In addition, the circuit board 60 is fixed to the holding plate 50 by a sealing body 70 filled in a gap 72 between the heat generating plate 30 and the circuit board 60. Therefore, thermal contraction of the circuit board 60 and the sealing body 70 is suppressed by the holding plate 50 made of ceramic, and the contraction amount of the circuit board 60 and the sealing body 70 approaches the contraction amount of the heat generating plate 30. As a result, the bending of the heat generating plate 30 caused by sealing is suppressed. Therefore, according to the present embodiment, the heat generation area 46 has high linearity, the contact between the heat generation area 46 and the platen roller 80 is good, and the image quality is improved.

  Further, when the circuit board 60 is pasted on the holding plate 50, for example, if a thermosetting resin (adhesive) such as an epoxy resin is used, the circuit board 60 and the holding plate 50 may be affected by the difference in thermal expansion coefficient. The substrate 60 and the holding plate 50 may be bent. In this embodiment, since the double-sided tape 56 is used, the circuit board 60 and the holding plate 50 are not curved.

[Second Embodiment]
A thermal print head according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a sectional view of the thermal print head. FIG. 3 is a schematic plan view of the thermal print head. In addition, since this embodiment is a modification of 1st Embodiment, duplication description is abbreviate | omitted.

  In the first embodiment, the circuit board 60 and the holding plate 50 are bonded together by the sealing body 70 filled in the gap 72 between the heat generating plate 30 and the circuit board 60.

  On the other hand, in the present embodiment, the heat generating plate 30 and the circuit board 60 are adjacent to each other, and the gap 72 between the heat generating plate 30 and the circuit board 60 is not formed. In the present embodiment, a plurality of through holes 74 penetrating the front and back are formed near the heat generating plate 30 of the circuit board 60. The plurality of through holes 74 are formed between the plurality of drive ICs 62, for example.

  The sealing body 70 is filled in the through hole 74. The sealing body 70 is bonded to the surface of the heat generating plate 30 near the circuit board 60, the surface of the circuit board 60 close to the heat generating plate 30, and the surface of the holding plate 50 facing the through hole 74.

  Also in this embodiment, the circuit board 60 and the holding plate 50 are bonded by the sealing body 70 filled in the through hole 74, so that the same effect as that of the first embodiment can be obtained.

[Other Embodiments]
The above embodiments are merely examples, and the present invention is not limited to these. For example, in the above embodiment, the drive IC 62 is placed on the surface of the circuit board 60 near the heat generating plate 30, but the drive IC 62 may be placed on the surface of the heat generating plate 30 near the circuit board 60. . Further, in the first embodiment, the flat glaze layer 36 is employed, but a convex glaze layer that rises along the heat generation region 46 may be employed.

  In the above embodiment, the circuit board 60 is a rigid board such as an epoxy board or a glass epoxy board, but may be a printed board using an insulating base material containing other resin. For example, the circuit board 60 may be a flexible board using an insulating base material including polyimide.

  Further, by combining the characteristic portions of the first embodiment and the second embodiment, the through hole 74 as described in the second embodiment is provided in the circuit board 60 of the thermal print head 10 of the first embodiment. May be formed.

DESCRIPTION OF SYMBOLS 10 ... Thermal print head, 20 ... Heat sink, 30 ... Heat generating plate, 32 ... Insulating substrate, 34 ... Support substrate, 36 ... Glaze layer, 38 ... Resistor layer, 40 ... Conductor layer, 42 ... Heat generating resistor part, 44 DESCRIPTION OF SYMBOLS ... Electrode, 46 ... Heat generating area, 48 ... Protective layer, 48a ... Opening of protective layer, 50 ... Holding plate, 54-56 ... Double-sided tape, 60 ... Circuit board, 62 ... Drive IC, 64 ... Connector, 66, 68 ... Bonding wire, 70 ... sealing body, 72 ... gap between heat generating plate and circuit board, 74 ... through hole in circuit board, 80 ... platen roller, 80a ... axis of platen roller, 80b ... outer peripheral surface of platen roller, 82 ... Recording medium, 91 ... main scanning direction, 92 ... sub-scanning direction,

Claims (11)

A heat sink made of metal,
A support substrate made of ceramic, a glaze layer stacked on the support substrate, a plurality of heating resistor portions formed on the glaze layer and arranged in the main scanning direction at intervals from each other, and the plurality of heating resistor portions A plurality of electrodes electrically connected to each other, and a heat generating plate placed on a part of the surface of the heat radiating plate and fixed to the heat radiating plate,
A holding plate made of ceramic and placed side by side in the sub-scanning direction with the heat generation plate on a part of the surface of the heat dissipation plate on which the heat generation plate is fixed;
A circuit board fixed on the holding plate;
A driving IC mounted on the circuit board or the heating plate and electrically connected to the circuit formed on the circuit board and the electrode formed on the heating plate;
A sealing body made of a thermosetting resin, covering the driving IC, and integrally bonding the heat generating plate, the circuit board and the holding plate;
A thermal print head comprising:   The sealing body is at least part of the surface of the heat generating plate opposite to the heat radiating plate, part of the surface of the circuit board opposite to the heat radiating plate, and opposite to the heat radiating plate of the holding plate. The thermal print head according to claim 1, wherein the thermal print head is bonded to a part of the surface on the side.   The driving IC and a circuit formed on the circuit board are connected by a first bonding wire, and the driving IC and the electrode formed on the heat generating plate are connected by a second bonding wire, and the sealing The thermal print head according to claim 1, wherein the body covers the first bonding wire and the second bonding wire.   2. The heating plate and the circuit board are arranged with a gap in the sub-scanning direction, and the sealing body is filled in a gap between the heating plate and the circuit board. The thermal print head as described in any one of thru | or 3.   5. The thermal print according to claim 1, wherein a through-hole penetrating front and back is formed in the circuit board, and the sealing body is filled in the through-hole. head.   6. The thermal print head according to claim 1, wherein the circuit board and the holding plate are attached with a double-sided tape.   The thermal print head according to any one of claims 1 to 6, wherein the sealing body is made of an epoxy resin.   The thermal print head according to claim 1, wherein the circuit board is a printed board using an insulating base material containing a resin.   The thermal print head according to claim 1, wherein the support substrate and the holding plate are made of the same ceramic.   The thermal print head according to claim 9, wherein the support substrate and the holding plate are made of alumina. A heat sink made of metal,
A support substrate made of ceramic, a glaze layer stacked on the support substrate, a plurality of heating resistor portions formed on the glaze layer and arranged in the main scanning direction at intervals from each other, and the plurality of heating resistor portions A plurality of electrodes electrically connected to each other, and a heat generating plate placed on a part of the surface of the heat radiating plate and fixed to the heat radiating plate,
A holding plate made of ceramic and placed side by side in the sub-scanning direction with the heat generation plate on a part of the surface of the heat dissipation plate on which the heat generation plate is fixed;
A circuit board fixed on the holding plate;
A driving IC mounted on the circuit board or the heating plate and electrically connected to the circuit formed on the circuit board and the electrode formed on the heating plate;
A sealing body made of a thermosetting resin, covering the driving IC, and integrally bonding the heat generating plate, the circuit board and the holding plate;
A thermal printer comprising: a thermal print head comprising: