JP2009061763A - Thermal print head and thermal printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain excellent heat radiation property while suppressing a thermal print head from curving. <P>SOLUTION: The thermal print head includes: a heating body plate 20 having a rectangular insulating substrate having the first and second faces facing each other and a heating resistive element forming a heating zone extending in a belt shape along the long side of the insulating substrate in the first face of the insulating substrate; a heat radiating plate 30 facing the second face of the insulating substrate; a thermoconductive material section 61 constituted by filling a highly thermoconductive gel between the part corresponding to the heating zone of the second face of the insulating substrate and the radiating plate 30; an adhesive section 62 fixing the heating body plate 20 and the radiating plate 30 with an adhesive at the center part of the insulating substrate in the long side direction; and a double-sided adhesive tape 63 adhering the heating body plate 20 and the heat radiating plate 30 in at least both the outer sides of the heating body plate 20 from the adhesive section 62 in the long side direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  A thermal print head is an output device that heats a plurality of heating resistors arranged in a heat generating area and forms images such as characters and figures on a printing medium such as a thermal recording paper by the heat. This thermal print head is widely used in recording devices such as barcode printers, digital plate-making machines, video printers, imagers, and seal printers.

  A general thermal print head includes a heat radiating plate, a heat generating plate attached to the heat radiating plate, and a circuit board attached to the heat radiating plate on the same side as the heat generating plate. A plurality of heating resistors are linearly arranged at predetermined intervals in a heating region extending in a band shape on the surface opposite to the surface of the heating plate opposite to the heat dissipation plate. The circuit board is mounted with electrical components such as a driving IC that is a part of a driving circuit for driving the heating resistor.

A printer using such a thermal print head generally includes a platen roller formed in a cylindrical shape with a material having a predetermined elasticity. The platen roller is disposed so that its side surface is in contact with the heat generating region with the main scanning direction in which the heat generating resistors are arranged as an axis, and is provided rotatably about the axis. Due to the rotation of the platen roller, the printing medium inserted between the platen roller and the heat generation area moves in the sub-scanning direction perpendicular to the main scanning direction. While pressing the printing medium to the heat generation area by the platen roller, the printing medium is moved in the sub-scanning direction, and the heat generation pattern of the heat generation area is changed along with the movement of the printing medium, so that a desired image is printed on the printing medium. To form.
Japanese Patent No. 3328735

  A heating element plate of a thermal head is generally a ceramic insulating substrate provided with a heating resistor. Moreover, a common heat sink is a flat plate made of metal such as aluminum. The heat generating plate and the heat radiating plate are fixed with an adhesive, for example. Since the insulating substrate has a smaller coefficient of thermal expansion than that of the heat radiating plate, the coefficient of thermal expansion between the insulating substrate and the heat radiating plate varies depending on heating during the manufacturing process and temperature change during operation of the thermal print head. For this reason, the thermal print head may be curved so that the heat radiating plate becomes convex toward the heating element plate.

  Patent Document 1 describes a method of suppressing bending by bonding a heat generating plate and a heat radiating plate using an adhesive that does not have elasticity after curing and an adhesive that has elasticity after curing. However, in the method described in Patent Document 1, since the space between the heat generating plate and the heat radiating plate is filled with an adhesive or a double-sided tape, heat transfer characteristics higher than that of the adhesive or the double-sided tape cannot be obtained. The heat dissipation characteristics cannot be improved.

  However, if the heat generating plate and the heat radiating plate are bonded to each other with a material having high heat conductivity in order to improve the heat radiating characteristics, the adhesive force is reduced. When the adhesive force between the heat generating plate and the heat radiating plate decreases, the relative force between the heat generating plate and the heat radiating plate is increased when a force is applied to move the heat generating plate in the sub-scanning direction due to rotation of the platen roller. A position change occurs. For this reason, the relative position change of a heat generating body board and a circuit board arises, and the bonding wire spanned over both may break.

  Therefore, an object of the present invention is to obtain good heat dissipation characteristics while suppressing the bending of a thermal print head.

  In order to solve the above-described problems, according to the present invention, in a thermal print head, a rectangular insulating substrate having a first surface and a second surface facing each other, and a first surface of the insulating substrate along a long side of the insulating substrate. A heating element plate including a heating resistor that forms a heating region extending in a strip shape, a heat dissipation plate facing the second surface of the insulating substrate, a portion corresponding to the heating region of the second surface of the insulating substrate, and the A heat transfer material part filled with a good heat transfer gel between the heat sink and an adhesive part for fixing the heat generating plate and the heat sink with an adhesive at the center in the long side direction of the insulating substrate; And a double-sided tape for bonding the heat generating plate and the heat radiating plate outside at least both sides in the long side direction than the central portion.

  According to the present invention, in a thermal printer for forming an image on a printing medium that changes color when heat is applied, a rectangular insulating substrate having a first surface and a second surface facing each other, and the insulating surface on the first surface of the insulating substrate. A heat generating plate having a heat generating resistor that forms a heat generating region extending in a strip shape along the long side of the substrate; a heat radiating plate facing the second surface of the insulating substrate; and the heat generation of the second surface of the insulating substrate. A heat transfer material portion filled with a good heat transfer gel between a portion corresponding to a region and the heat dissipation plate, and an adhesive for fixing the heating element plate and the heat dissipation plate at a central portion in the long side direction of the insulating substrate The heat generating region extends while pressing the printed material against the heat generating region, the adhesive, the double-sided tape that bonds the heat generating plate and the heat radiating plate at least on the outer side in the long side direction than the central portion Move in a direction perpendicular to the direction Characterized by comprising the Latin roller, the.

  According to the present invention, it is possible to obtain good heat dissipation characteristics while suppressing the bending of the thermal print head.

  An embodiment of a thermal print head according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or similar structure, and the overlapping description is abbreviate | omitted.

[First Embodiment]
FIG. 1 is a cross-sectional view taken along arrows II in FIGS. 2 and 3 in the first embodiment of the thermal print head according to the present invention. 2 is a cross-sectional view taken along the line II-II in FIG. 3 is a cross-sectional view taken along the line III-III in FIG. FIG. 4 is a partially cutaway perspective view of the thermal print head in the present embodiment.

  The thermal print head 10 of the present embodiment has a heat generating plate 20 and a heat radiating plate 30.

  The heating element plate 20 includes an insulating substrate 22 formed in a rectangular plate shape with an insulating material, and a heating resistor 26 that forms a heating region 24 extending in a strip shape along the long side on one surface of the insulating substrate 22. I have. The insulating substrate 22 is a flat plate made of an insulating material such as alumina.

  The heating resistor 26 is formed by, for example, a resistor layer 23 extending in the short side direction with a predetermined interval in the long side direction of the insulating substrate 22 and a metal wiring layer 28 formed on the surface of the resistor layer 23. Has been. In the metal wiring layer 28, a notch is formed in a part in the short side direction of the insulating substrate 22, and a portion of the resistor layer 23 that does not overlap with the metal wiring layer 28 becomes the heating resistor 26.

  Further, a protective film layer 29 covering the insulating substrate 22, the heating resistor 26 and the metal wiring layer 28 may be formed. A glaze layer may be formed between the insulating substrate 22 and the heating resistor 26.

  A drive circuit that generates heat from the heating resistor 26 is formed on the circuit board 40 by a driving IC 42, for example. The driving IC 42 and the metal wiring layer 28 are electrically connected by, for example, a bonding wire 44. Further, the driving IC 42 and the wiring pattern formed on the circuit board 40 are also electrically connected by, for example, bonding wires 44. The driving IC 42 and the bonding wire 44 are sealed with a resin 48, for example. A control signal and driving power for forming a predetermined heat generation pattern in the heat generation region 24 are input to the circuit board 40 via the connector 46, for example.

  The heat sink 30 is a plate formed of a metal such as aluminum. The heat generating plate 20 is placed on the heat radiating plate 30 on the back surface of the heat generating region 24. The circuit board 40 is placed on the same surface as the surface on which the heat generating plate 20 of the heat radiating plate 30 is placed via, for example, an adhesive 64.

  A heat transfer material part 61, an adhesive part 62 and a double-sided tape 63 are arranged between the heat generating plate 20 and the heat radiating plate 30. In the present embodiment, the adhesive portion 62 and the double-sided tape 63 are arranged on the same line.

  The heat transfer material portion 61 is formed by filling a good heat transfer gel between a portion corresponding to the heat generating region 24 on the back side of the insulating substrate 22 and the heat radiating plate 30. The adhesive portion 62 is a portion for fixing the heat generating plate 20 and the heat radiating plate 30 with an adhesive at the central portion in the long side direction of the insulating substrate 22. The double-sided tape 63 is disposed outside the adhesive portion 62 in the long side direction of the insulating substrate 22 and adheres the heat generating plate 20 and the heat radiating plate 30.

  The adhesive that fixes the heating element plate 20 and the heat radiating plate 30 with the adhesive portion 62 is, for example, an acrylic or epoxy resin. The good heat transfer gel filled in the heat transfer material part 61 is a gel-like substance having a higher thermal conductivity than at least the adhesive part 62 and the double-sided tape 63, and is, for example, a silicon resin containing alumina powder. The good heat transfer gel has higher elasticity than the adhesive and the double-sided tape 63 that fix the heat generating plate 20 and the heat radiating plate 30 at the adhesive portion 62. The adhesive portion 62 is formed, for example, by filling an area of about 1/10 to 1/3 of the length of the insulating substrate 22 in the long side direction.

  FIG. 5 is a partial cross-sectional view of the thermal printer in the present embodiment.

  A thermal printer using the thermal print head 10 of the present embodiment has a platen roller 50 formed in a cylindrical shape with a material having a predetermined elasticity. The platen roller 50 has a shaft 52 on a straight line parallel to the main scanning direction in which the heat generating region 24 extends. Further, the side surface of the platen roller 50 is disposed so as to be in contact with the heat generating region 24, and is provided so as to be rotatable about the shaft 52.

  Due to the rotation of the platen roller 50, the printing medium 54 such as thermal paper inserted between the platen roller 50 and the heat generating area 24 moves in the sub-scanning direction perpendicular to the main scanning direction. While the printing medium 54 is pressed against the heat generation area 24 by the platen roller 50, the printing medium 54 is moved in the sub-scanning direction, and the heat generation pattern of the heat generation area 24 is changed along with the movement of the printing medium 54, so that a desired An image is formed on the medium.

  In the thermal printer using the thermal print head 10, an image is formed on the printing medium 54 by the heat generation pattern in the heat generation area 24, so that the heat generation area 24 is as close to a straight line as possible and relatively to the platen roller 50. It is preferable to keep it from moving. Generally, since the thermal print head 10 is fixed to the housing of the printer by the heat radiating plate 30, it is preferable that the heat generating region 24 does not move relative to the heat radiating plate 30. Therefore, it is preferable that the heat transfer material portion 61 and the adhesive portion 62 be as close as possible so that the heat generating region 24 located on the opposite side of the heat transfer material portion 61 is not moved relative to the heat radiating plate 30.

  Further, the heat radiating plate 30 may be formed with a groove 32 between the heat transfer material portion 61 and the adhesive portion 62. By forming the groove 32 in the heat sink 30 in this way, the heat transfer gel is applied to the portion of the heat sink 30 that contacts the heat transfer material portion 61 and the adhesive is applied to the portion of the heat sink 30 that contacts the adhesive portion 62. The gel and adhesive will not mix.

  In such a thermal print head 10, since the heat conductive gel is disposed on the back side of the heat generating region 24, the heat generated in the heat generating region 24 is quickly transmitted to the heat radiating plate 30, and good heat dissipation characteristics are obtained. Further, since the central portion in the long side direction of the insulating substrate 22 is fixed with an adhesive, a sufficient adhesive force can be provided between the insulating substrate 22 and the heat sink 30. As a result, even if a force for moving the heat generating plate 20 in the sub-scanning direction is applied by, for example, rotation of the platen roller 50, the heat generating plate 20 as a whole suppresses a relative position change with respect to the heat radiating plate 30. can do. For this reason, the relative position change of the heat generating body plate 20 and the circuit board 40 is also suppressed, and the breakage of the bonding wire 44 can be suppressed.

  On the other hand, the outer side portion of the adhesive portion 62 is bonded with a double-sided tape 63. The double-sided tape 63 has elasticity and can be deformed to some extent in the direction in which the insulating substrate 22 and the heat dissipation plate 30 spread. For this reason, even if there is a difference in expansion or contraction due to thermal expansion between the insulating substrate 22 and the heat radiating plate 30, the difference is absorbed by the double-sided tape 63 at the outer portion in the long side direction of the heating element plate 20 to be insulated. The curvature of the substrate 22 and the heat sink 30 can be suppressed.

  In the present embodiment, since the adhesive portion 62 and the double-sided tape 63 are arranged on the same line, even if the insulating substrate 22 is short in the short side direction, the adhesive portion 62 and the double-sided tape 63 are provided. It is easy to secure space to arrange.

  As described above, the thermal print head 10 of the present embodiment has good heat dissipation characteristics, has a sufficient adhesive force between the heat generating plate 20 and the heat dissipation plate 30, and further, the insulating substrate 22 and the heat dissipation plate 30. Bending is suppressed.

[Second Embodiment]
FIG. 6 is a sectional view of a thermal print head according to a second embodiment of the present invention.

  The thermal print head 10 of this embodiment (see, for example, FIG. 4) is different from that of the first embodiment in the arrangement of the adhesive portion 62 and the double-sided tape 63 between the heat generating plate 20 and the heat radiating plate 30. Yes. As in the first embodiment, the heat transfer material portion 61 is provided between the portion corresponding to the heat generation region 24 (for example, see FIG. 2) on the back side of the insulating substrate 22 (for example, see FIG. 2) and the heat radiating plate 30. To position.

  In the present embodiment, the adhesive portion 62 is located in the central portion of the insulating substrate 22 in the long side direction. However, unlike the first embodiment, it is located on the opposite side of the circuit board 40 across the heat transfer material portion 61. Further, the double-sided tape 63 is arranged over the entire long side direction of the heating element plate 20. Even in this case, the double-sided tape 63 is also arranged outside the adhesive portion 62 in the long side direction of the insulating substrate 22 to bond the heat generating plate 20 and the heat radiating plate 30 together.

  Even in such a thermal print head 10, good heat dissipation characteristics can be obtained because the heat conductive gel is disposed on the back side of the heat generating region 24. Further, since the central portion in the long side direction of the insulating substrate 22 is fixed with an adhesive, a sufficient adhesive force can be provided between the insulating substrate 22 and the heat sink 30. Further, even if a difference in expansion or contraction due to thermal expansion occurs between the insulating substrate 22 and the heat radiating plate 30, the difference is absorbed by the double-sided tape 63 to suppress the bending of the insulating substrate 22 and the heat radiating plate 30. it can.

  As described above, the thermal print head 10 of the present embodiment has good heat dissipation characteristics, has a sufficient adhesive force between the heat generating plate 20 and the heat dissipation plate 30, and further, the insulating substrate 22 and the heat dissipation plate 30. Bending is suppressed. Further, in the present embodiment, when the adhesive portion 62 can be disposed on the same line as the double-sided tape 63, the double-sided tape 63 can be disposed over the entire long side direction of the heating plate 20, and therefore the insulating substrate 22. And a larger difference in expansion or contraction between the heat sink 30 and the heat sink 30 can be absorbed.

[Third Embodiment]
FIG. 7 is a sectional view of a thermal print head according to a third embodiment of the present invention.

  The thermal print head 10 of this embodiment (see, for example, FIG. 4) is different from that of the first embodiment in the arrangement of the adhesive portion 62 and the double-sided tape 63 between the heat generating plate 20 and the heat radiating plate 30. Yes. As in the first embodiment, the heat transfer material portion 61 is provided between the portion corresponding to the heat generation region 24 (for example, see FIG. 2) on the back side of the insulating substrate 22 (for example, see FIG. 2) and the heat radiating plate 30. To position. Further, the adhesive portion 62 is located at the central portion of the insulating substrate 22 in the long side direction.

  In the present embodiment, the double-sided tape 63 is disposed so as to extend over substantially the entire area between the heat generating plate 20 and the heat radiating plate 30. In this double-sided tape 63, portions corresponding to the heat transfer material portion 61 and the adhesive portion 62 are cut out, and the heat transfer material portion 61 and the adhesive portion 62 are filled with gel and an adhesive, respectively. Formed by.

  Even in such a thermal print head 10, a good heat transfer gel is disposed on the back side of the heat generating region 24, and thus good heat dissipation characteristics can be obtained. Further, since the central portion in the long side direction of the insulating substrate 22 is fixed with an adhesive, a sufficient adhesive force can be provided between the insulating substrate 22 and the heat sink 30. Further, even if a difference in expansion or contraction due to thermal expansion occurs between the insulating substrate 22 and the heat radiating plate 30, the difference is absorbed by the double-sided tape 63 to suppress the bending of the insulating substrate 22 and the heat radiating plate 30. it can.

  As described above, the thermal print head 10 of the present embodiment has good heat dissipation characteristics, has a sufficient adhesive force between the heat generating plate 20 and the heat dissipation plate 30, and further, the insulating substrate 22 and the heat dissipation plate 30. Bending is suppressed. Further, in the present embodiment, when the adhesive portion 62 can be disposed on the same line as the double-sided tape 63, the double-sided tape 63 can be disposed over the entire long side direction of the heating plate 20, and therefore the insulating substrate 22. And a larger difference in expansion or contraction between the heat sink 30 and the heat sink 30 can be absorbed.

[Other embodiments]
The above description is merely an example, and the present invention is not limited to the above-described embodiments, and can be implemented in various forms. For example, the adhesive portion may be provided on a plurality of portions such as disposed on both sides in the short side direction of the insulating substrate with the heat transfer material portion interposed therebetween to obtain a necessary adhesive force. Moreover, it can also implement combining the characteristic of each embodiment.

FIG. 4 is a cross-sectional view taken along arrows II in FIGS. 2 and 3 in the first embodiment of the thermal print head according to the present invention. It is II-II arrow sectional drawing in FIG. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 1. 1 is a partially cutaway perspective view of a thermal print head according to a first embodiment of the present invention. 1 is a cross-sectional view of a part of a thermal printer in a first embodiment of a thermal print head according to the present invention. It is sectional drawing in 2nd Embodiment of the thermal print head concerning this invention. It is sectional drawing in 3rd Embodiment of the thermal print head concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Thermal print head, 20 ... Heat generating board, 22 ... Insulating substrate, 23 ... Resistor layer, 24 ... Heat generating area, 26 ... Heat generating resistor, 28 ... Metal wiring layer, 29 ... Protective film layer, 30 ... Heat sink , 32 ... groove, 40 ... circuit board, 42 ... driving IC, 44 ... bonding wire, 46 ... connector, 48 ... resin, 50 ... platen roller, 52 ... shaft, 54 ... printed material, 61 ... heat transfer material part 62 ... Adhesive part, 63 ... Double-sided tape, 64 ... Adhesive

Claims (7)

A heating element comprising a rectangular insulating substrate having a first surface and a second surface facing each other, and a heating resistor forming a heating region extending in a strip shape along the long side of the insulating substrate on the first surface of the insulating substrate The board,
A heat sink facing the second surface of the insulating substrate;
A heat transfer material portion filled with a good heat transfer gel between the portion corresponding to the heat generation region of the second surface of the insulating substrate and the heat radiating plate;
An adhesive portion for fixing the heat generating plate and the heat radiating plate with an adhesive at a central portion in the long side direction of the insulating substrate;
A double-sided tape that bonds the heat generating plate and the heat radiating plate outside at least both of the long side direction than the adhesive portion;
A thermal print head comprising:   The thermal print head according to claim 1, wherein the double-sided tape and the adhesive portion are arranged on the same line.   The thermal print head according to claim 1, wherein the double-sided tape is disposed over the entire long side direction of the insulating substrate.   4. The thermal print head according to claim 1, wherein the heat radiating plate has a groove formed between the adhesive portion and the heat transfer material portion. 5.   5. The thermal print head according to claim 1, wherein the adhesive portion is provided close to the heat transfer portion and a short side direction of the insulating substrate.   The circuit board provided with the drive circuit which drives the said heating resistor, and the bonding wire spanned between the said drive circuit and the said heat generating board are comprised, The 1 thru | or Claim characterized by the above-mentioned. Item 6. The thermal print head according to any one of Items 5. In a thermal printer that forms an image on a substrate that changes color when heat is applied,
A heating element comprising a rectangular insulating substrate having a first surface and a second surface facing each other, and a heating resistor forming a heating region extending in a strip shape along the long side of the insulating substrate on the first surface of the insulating substrate The board,
A heat sink facing the second surface of the insulating substrate;
A heat transfer material portion filled with a good heat transfer gel between the portion corresponding to the heat generation region of the second surface of the insulating substrate and the heat radiating plate;
An adhesive for fixing the heat generating plate and the heat radiating plate at the center in the long side direction of the insulating substrate;
A double-sided tape that bonds the heat generating plate and the heat radiating plate at least on the outside in the long side direction than the central portion;
A platen roller that moves in a direction perpendicular to a direction in which the heat generating area extends while pressing the printing medium against the heat generating area;
A thermal printer comprising:

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