JP2016190463A - Thermal print head and thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal print head and a thermal printer capable of easily securing desired printing pressure.SOLUTION: A head substrate 11 is formed by laminating: a glaze layer 22; a heating resistor layer 23; an electrode 24; and a protection coating layer 25, on a ceramic substrate 21 serving as an insulation plate. The glaze layer 22 is a protrusive state and is provided only on a lower side of a heating area 20 formed by the plural heating resistors, on the whole one surface of the ceramic substrate. Since only the part of the heating area protrudes and presses a peripheral side face of a platen roller, desired printing pressure can be secured easily.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thermal print head that is an image recording device and a thermal printer having the same.

  Thermal print heads are attracting attention as output devices such as video printers, imagers, and seal printers. The thermal print head prints on a medium such as thermal paper, plate-making film, photographic paper, media, etc. due to the heat generated in the heat generating area formed by a plurality of heating resistors arranged on the head substrate, and has low noise, Various developments have been made to provide advantages such as low running costs.

  In general, a thermal print head has a support base in which a glaze layer is formed as a heat retaining layer on a ceramic substrate such as alumina. A heating resistor layer and a conductive layer to be an electrode are laminated on the support substrate by a thin film forming method such as sputtering, and then the heating resistor and the electrode are patterned by a photoengraving process. Thereafter, a protective coating layer is formed by a thin film forming method such as a sputtering method to cover the heating resistor and a predetermined portion of the electrode.

  The head substrate manufactured in this manner and the separately manufactured drive circuit substrate are fixed to the surface of the heat dissipation substrate. Further, the electrodes of the head substrate and the driving IC mounted on the driving circuit substrate are connected by a connecting member such as a bonding wire, and the driving IC is sealed with resin to manufacture a thermal print head (for example, Patent Documents). 1).

  A thermal printer using such a thermal print head generally has a platen roller formed in a cylindrical shape with a material having a predetermined elasticity. The platen roller has an axis parallel to the main scanning direction, and is arranged so that the peripheral side surface is in contact with the heat generating area on the head substrate.

  In such a thermal printer, for example, the heat dissipation substrate is pressed from the back side to the platen roller side with a spring or the like, and the medium inserted between the peripheral side surface of the platen roller and the heat generation region is pressed against the heat generation region. Printing on a medium is performed.

JP 2008-230126 A

  Incidentally, as shown in FIG. 5, the conventional thermal print head has a predetermined position on the ceramic substrate 100 and a position away from the predetermined position toward the drive circuit board, respectively, in the main scanning direction (from the front side in the figure). Glaze layers 101 and 102 extending in the direction toward the back side are formed.

  The glaze layer 101 formed at a position far from the drive circuit board is a glaze layer mainly functioning as a heat retaining layer of the heat generating region 103, and a protrusion having a cross-sectional shape obtained by cutting a part of a circle with a straight line. It has become. This glaze layer 101 is referred to herein as a heat generation region glaze layer 101. A heat generation region 103 is formed on the heat generation region glaze layer 101. As a result, the heat generating region 103 also becomes a protrusion, and the peripheral side surface of the platen roller 104 is deformed along with the shape of the heat generating region 103.

  On the other hand, the glaze layer 102 formed at a position closer to the drive circuit board is mainly for smoothing the electrode 105 and facilitating the connection between the electrode 105 and the connection member. It is formed in a shape. Here, the glaze layer 102 is referred to as an electrode glaze layer 102. The electrode 105 has a smoothed portion laminated on the top portion of the electrode glaze layer 102, and a connecting member (not shown) is connected to the smoothed portion.

  In the case of such a conventional thermal print head, two portions, a portion where the heat generation region glaze layer 101 is formed and a portion where the electrode glaze layer 102 is formed protrude to the platen roller 104 side. If the gap between the glaze layer 101 and the electrode glaze layer 102 is narrow, a part of the protruding portion on the electrode glaze layer 102 side presses the peripheral side surface of the platen roller 104. As a result, a medium (not shown) ) Is pressed against the heat generating area 103 (this is called the printing pressure) and the printing is rubbed. That is, the conventional thermal print head has a problem that it is difficult to ensure a desired printing pressure.

  Therefore, an object of the present invention is to provide a thermal print head and a thermal printer that can easily secure a desired printing pressure.

  In order to achieve the above-described object, a thermal print head according to the present invention includes a glaze layer on one surface of an insulating plate, and a plurality of heating resistors laminated on the glaze layer and arranged in a predetermined direction. A heating resistor layer, an electrode laminated on the heating resistor layer, for supplying current to the heating resistor, and a protective coating layer for protecting the heating resistor and the electrode are provided. The glaze layer has a protruding shape and is disposed only below the heat generating area formed by the plurality of heat generating resistors of the entire surface of the insulating plate. It is characterized by being.

  According to the present invention, since the glaze layer of the protrusion is provided only on the lower side of the heat generating area, only the portion of the heat generating area protrudes and presses the peripheral side surface of the platen roller. The pressure can be easily secured.

It is a fragmentary sectional view of a head substrate of a thermal print head in a 1st embodiment concerning the present invention. 1 is a partially cut-out top view of a thermal print head according to a first embodiment of the present invention. 1 is a partial cross-sectional view of a thermal printer using a thermal print head according to a first embodiment of the present invention. It is a fragmentary sectional view of a head substrate of a thermal print head in a 2nd embodiment concerning the present invention. It is a fragmentary sectional view of the head substrate of the conventional thermal print head.

  Embodiments of a thermal printer and a thermal print head according to the present invention will be described with reference to the drawings. This embodiment is merely an example, and the present invention is not limited to this.

[1. First Embodiment]
[1-1. Configuration of thermal print head and thermal printer]
FIG. 1 is a partial sectional view of a head substrate in a first embodiment of a thermal print head according to the present invention. FIG. 2 is a partially cut-out top view of the thermal print head according to the first embodiment. FIG. 3 is a partial cross-sectional view of a thermal printer using the thermal print head according to the first embodiment.

  As shown in FIG. 3, the thermal print head 10 according to the first embodiment includes a head substrate 11, a drive circuit substrate 12, and a heat radiating plate 13. The head substrate 11 and the drive circuit substrate 12 are respectively attached to the same surface side of the heat radiating plate 13. On the head substrate 11, a belt-like heat generating region 20 extending in the main scanning direction indicated by an arrow A in FIG. The heat sink 13 is a rectangular flat plate made of a metal such as aluminum. A control signal and drive power for forming a predetermined heat generation pattern in the heat generation region 20 of the head substrate 11 are input to the drive circuit substrate 12 and further input to the head substrate 11 electrically connected to the drive circuit substrate 12. Is done.

  A thermal printer 30 using the thermal print head 10 has a platen roller 31 (see FIG. 3) formed in a cylindrical shape with a material having a predetermined elasticity. The platen roller 31 has a shaft 32 parallel to the main scanning direction, and is disposed so that the peripheral side surface is in contact with the heat generating region 20 of the head substrate 11.

  By the rotation of the platen roller 31, the thermal recording medium 33 inserted between the platen roller 31 and the heat generating area 20 moves in the sub-scanning direction (direction indicated by arrow B in FIG. 3) orthogonal to the main scanning direction. . The thermal recording medium 33 is, for example, thermal paper that develops color when heated to a color development temperature or higher. The thermal printer 30 moves the thermal recording medium 33 in the sub-scanning direction while pressing the thermal recording medium 33 against the heat generation area 20 by the platen roller 31, and changes the heat generation pattern of the heat generation area 20 to change a desired image. Are formed on the thermal recording medium 33.

  As shown in FIG. 1, the head substrate 11 is obtained by laminating a glaze layer 22, a heating resistor layer 23, an electrode 24, and a protective coating layer 25 on a ceramic substrate 21 as an insulating plate.

  The ceramic substrate 21 is a rectangular flat plate formed of an insulating material such as alumina, for example, and the longitudinal direction of the ceramic substrate 21 is parallel to the main scanning direction and the short side direction is parallel to the sub-scanning direction. The drive circuit board 12 is adjacent to one long side of the ceramic substrate 21 (left side in FIG. 1).

  The glaze layer 22 is a ridge extending in the main scanning direction with a cross-sectional shape obtained by cutting a part of a circle with a straight line, and is formed of an insulating material such as glass. The glaze layer 22 is not provided on the entire surface (surface) of the ceramic substrate 21, but at a position close to the long side opposite to the long side adjacent to the drive circuit substrate 12 in the entire surface. Only provided.

  Further, a heating resistor layer 23 is laminated on one surface of the ceramic substrate 21 so as to extend in the sub-operation direction so as to straddle the glaze layer 22 and to be spaced apart in the main operation direction. Further, an electrode 24 made of, for example, aluminum is laminated on the heating resistor layer 23. The electrode 24 has a notch formed in a part (for example, the top) of the portion straddling the glaze layer 22. In the heating resistor layer 23, a portion located below the notch, that is, a portion not overlapping the electrode 24 becomes the heating resistor 26. The heating resistor 26 generates heat when a current is passed through the electrode 24.

  In other words, the plurality of heating resistors 26 are arranged on the glaze layer 22 at intervals in the main operation direction. The plurality of heating resistors 26 form a belt-like heating region 20 extending in the main operation direction. Furthermore, a protective coating layer 25 is formed on one surface of the ceramic substrate 21 to cover these necessary parts in order to protect the heating resistor 26 and the electrode 24.

  On the other hand, on the drive circuit board 12 (see FIGS. 2 and 3), a drive circuit for generating heat in the heat generating region 20 is formed. This drive circuit has electrical components such as a drive IC 40, for example. The driving IC and the pad portion 24A exposed from the vicinity of the long side of the electrode 24 of the head substrate 11 adjacent to the driving circuit substrate 12 are electrically connected by a bonding wire 41. Further, the driving IC 40 and the wiring pattern of the driving circuit of the driving circuit board 12 are electrically connected by a bonding wire 42 (see FIG. 3). Further, the driving IC 40 and the bonding wires 41 and 42 are sealed with a resin 43, for example.

  The configurations of the thermal print head 10 and the thermal printer 30 in the first embodiment are as described above.

[1-2. Manufacturing method of thermal print head]
Next, an example of a method for manufacturing the thermal print head 10 will be briefly described. First, an insulating plate is formed from ceramic. The insulating plate is sized so that a plurality of finally manufactured head substrates 11 are cut out. Next, a glass paste is pattern printed on the insulating plate. The glass paste printed here is a pattern in which a band-like raised portion is formed at a position where the glaze layer 22 of the ridge is formed. Next, the insulating plate on which the glass paste is printed is fired. Thereby, the glass on which the pattern is printed is melted and fixed to the insulating plate. As a result, the glaze layer 22 of the protrusion is formed at a predetermined position.

  Further, the heating resistor layer 23 and the conductive layer to be the electrode 24 are laminated on the insulating plate and the glaze layer 22 by a thin film formation method such as sputtering, and then the heating resistor 26 is formed by a photoengraving process. The electrode 24 is patterned. Thereafter, a protective coating layer 25 that covers predetermined portions of the heating resistor 26 and the electrode 24 is formed by a thin film forming method such as sputtering.

  Next, the insulating plate on which the protective coating layer 25 is formed is divided into a plurality of head substrates 11 by cutting by dicing or the like. Then, each divided head substrate 11 is placed on the heat radiating plate 13 together with the drive circuit substrate 12. Further, the head substrate 11 and the drive circuit substrate 12 are wire-bonded and connected by bonding wires 41 and 42, and the connection portion is sealed with the resin 43, whereby the thermal print head 10 is completed.

[1-3. Summary and Effect]
As described above, the thermal print head 10 according to the first embodiment includes the plurality of heating resistors 26 in which the glaze layer 22 of the protrusions is arranged in the main scanning direction on the entire surface of the ceramic substrate 21. Is provided only on the lower side of the heat generating region 20 formed by the above.

  As a result, the head substrate 11 of the thermal print head 10 is such that only the portion of the heat generating region 20 protrudes toward the platen roller 31 by the glaze layer 22 of the protrusions, and presses the peripheral side surface of the platen roller 31. Thus, it is possible to prevent a situation in which the print pressure is weakened by pressing the peripheral side surface of the platen roller 31 also in the portion other than the heat generating area 20 as in the prior art, and thus the desired print pressure can be easily secured. it can.

  By the way, in the case of the thermal print head 10, since the electrode glaze layer for smoothing the electrode 24 is omitted, the smoothness of the pad portion 24A to which the bonding wire 41 is connected (how smooth the surface is) May be reduced).

  Therefore, for example, when the thermal print head 10 is manufactured, the electrode 24 may be divided into two layers, and the electrode 24 may be made into two layers. In this case, the smoothness of the upper electrode 24 connected to the bonding wire 41 (that is, the smoothness of the surface of the pad portion 24A) is improved as compared with the case where the electrode 24 is a single layer.

  In this way, the electrode glaze layer is omitted, but the smoothness of the pad portion 24A of the electrode 24 is prevented from being lowered, and the bonding wire 41 to which the electrode 24 and the electrode 24 are connected is firmly and easily connected. Can be connected.

[2. Second Embodiment]
Next, a second embodiment will be described. In the second embodiment, a part of the head substrate 11 of the thermal print head 10 is different from the first embodiment. Therefore, here, the configuration of the head substrate 11 will be mainly described.

[2-1. Configuration of head substrate]
FIG. 4 is a partial cross-sectional view of the head substrate 11 in the second embodiment of the thermal print head 10 according to the present invention. In FIG. 4, the same parts as those in FIG.

  As shown in FIG. 4, the head substrate 11 is formed by laminating a glaze layer 22, a heating resistor layer 23, an electrode 24, and a protective coating layer 25 on a ceramic substrate 21 as in the first embodiment. is there. The second embodiment is different from the first embodiment in that a bump 50 interposed between the bonding wire 41 and the electrode 24 is formed on the pad portion 24A of the electrode 24. is there.

  The bumps 50 are made of, for example, a conductive material such as gold, and are formed so that the front surface is exposed from the protective coating layer 25 while the back surface is in contact with the pad portion 24A of the electrode 24. The bump 50 is formed so as to have the same thickness as the protective coating layer 25 or a thickness slightly larger than the thickness of the protective coating layer 25 (that is, the same thickness). . Thereby, the surface of the bump 50 becomes the same surface as the surface of the protective coating layer 25 or a surface slightly protruding from the surface of the protective coating layer 25.

  Then, one end of a bonding wire 41 for connecting to the driving IC 40 is connected to the surface of the bump 50. That is, the electrode 24 and the driving IC 40 are connected by wire bonding via the bumps 50.

[2-2. Manufacturing method of thermal print head]
Next, an example of a method for manufacturing the thermal print head 10 will be briefly described. Here, the same parts as those in the first embodiment are omitted as appropriate. First, the glaze layer 22 of a protrusion is formed in the predetermined position of an insulating board by pattern-printing and baking a glass paste on an insulating board.

  Further, after the heating resistor layer 23 and the conductive layer to be the electrode 24 are laminated on the insulating plate and the glaze layer 22, the heating resistor 26 and the electrode 24 are patterned. Thereafter, a protective coating layer 25 that covers predetermined portions of the heating resistor 26 and the electrode 24 is formed.

  Next, the bump 50 is formed on the pad portion 24 </ b> A of the electrode 24. Thereafter, the insulating plate is divided into a plurality of head substrates 11, and each divided head substrate 11 is placed on the heat radiating plate 13 together with the drive circuit substrate 12. Further, the head substrate 11 and the drive circuit substrate 12 are wire-bonded and connected by bonding wires 41 and 42, and the connection portion is sealed with the resin 43, whereby the thermal print head 10 is completed.

[2-3. Summary and Effect]
As described so far, the thermal print head 10 according to the second embodiment forms the bump 50 between the electrode 24 and the bonding wire 41 instead of omitting the electrode glaze layer for smoothing the electrode. I tried to do it. The bump 50 is made of, for example, gold, and is formed on the pad portion 24 </ b> A of the electrode 24, so that the smoothness is improved more than the smoothness of the surface of the electrode 24.

  By doing so, the bump 50 and the bonding wire 41 can be firmly and easily connected to each other even though the electrode glaze layer is omitted. In other words, the electrode 24 and the bonding wire 41 can be firmly and easily connected via the bump 50.

  Further, as in the first embodiment, after the electrodes 24 are stacked twice and stacked, the bumps 50 may be formed thereon. In this way, the smoothness of the surface of the bump 50 can be further improved.

  Further, since the bump 50 has the same thickness as that of the protective coating layer 25, the platen roller 31 is not pressed unlike the conventional electrode glaze layer. Therefore, the thermal print head 10 according to the second embodiment can prevent a situation in which the printing pressure is weakened as in the first embodiment, and can easily secure a desired printing pressure. Can do.

[3. Other Embodiments]
[3-1. Other Embodiment 1]
In the second embodiment described above, the electrode 24 of the head substrate 11 and the driving IC 40 of the driving circuit substrate 12 are connected by the bonding wires 41 via the bumps 50. For example, the electrode 24 and the driving IC 40 may be connected only via the bump 50 without using the bonding wire 41.

  In this case, for example, after the bump 50 is fixed to the driving IC 40, the driving IC 40 is positioned on the pad portion 24A of the electrode 24 so that the pad portion 24A and the bump 50 are in contact with each other, and the bump 50 is melted. As a result, the electrode 24 and the driving IC 40 to be connected to the electrode 24 may be connected via the bump 50.

[3-2. Other Embodiment 2]
Further, in the first embodiment described above, in order to improve the smoothness of the electrode 24, the electrode 24 is laminated in two steps. However, the present invention is not limited to this. For example, the electrode 24 is divided into three or more times. May be laminated.

[3-3. Other Embodiment 3]
Furthermore, in the second embodiment described above, the bumps 50 are formed of a conductive material such as gold, but actually, for example, the bumps 50 are made of solder made of an alloy mainly composed of lead and tin. It may be formed. Incidentally, it is desirable that the material of the bump 50 has a melting point lower than that of the electrode 24.

[3-4. Other Embodiment 4]
Further, the configuration of the thermal print head 10 of each embodiment described above is merely an example, and the configuration of portions other than the glaze layer 22 may be different from the configuration of each embodiment described above.

  DESCRIPTION OF SYMBOLS 10 ... Thermal print head, 11 ... Head substrate, 12 ... Drive circuit board, 13 ... Heat sink, 20, 103 ... Heat generation area, 21, 100 ... Ceramic substrate, 22 ... Glaze layer, 23 ... ... heating resistor layer, 24, 105 ... electrode, 24A ... pad part, 25 ... protective coating layer, 26 ... heating resistor, 30 ... thermal printer, 31, 104 ... platen roller, 40 ... Driving IC, 41, 42 ... bonding wire, 50 ... bump.

Claims (7)

On one surface of the insulating plate, a glaze layer, a heating resistor layer that is stacked on the glaze layer and becomes a plurality of heating resistors, and stacked on the heating resistor layer, are stacked on the heating resistor layer. A thermal print head having a head substrate provided with an electrode for supplying current to the heating resistor, and a protective coating layer for protecting the heating resistor and the electrode,
The glaze layer has a protruding shape, and is disposed only below the heat generation area formed by the plurality of heat generation resistors in the entire surface of the insulating plate. Furthermore, it has a drive circuit board and a heat sink,
The head substrate and the drive circuit substrate are placed side by side on the heat sink,
2. The thermal print head according to claim 1, wherein the heat generating region is provided at a position adjacent to an end of the head substrate opposite to an end adjacent to the drive circuit substrate. The thermal print head according to claim 2, wherein the head substrate and the drive circuit substrate are connected by wire bonding. The electrode is
In the vicinity of the edge of the head substrate adjacent to the drive circuit substrate, a pad portion that is not covered with the protective coating layer is provided, and on the pad portion, between the electrode and a connection partner of the electrode. The thermal print head according to claim 2, wherein an intervening conductive bump is formed. The bump is
The thermal print head according to claim 4, wherein the thermal print head has the same thickness as the protective coating layer. The thermal print head according to claim 1, wherein the electrode is formed by being laminated in a plurality of times at the time of manufacture. A thermal printer comprising the thermal print head according to claim 1.

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