JP2013202968A - Thermal print head and thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an end of a head board from being broken.SOLUTION: A thermal print head is provided with a ceramic board 22, a glaze layer 25, heat generating resistors 26, an electrode layer 28, and a protective film 29. The ceramic board 22 is a rectangular board having an upper surface 71, a tilted surface 72 connected to an upper surface 71 and tilted with respect to the upper surface 71, and a bottom surface 70 facing the upper surface 71 and tilted surface 72. The glaze layer 25 covers the tilted surface 72, and has a ridge line 76 farther from the bottom surface 70 than from the upper surface 71. The heat generating resistors 26 extend across the ridge line 76 on a surface of the glaze layer 25, and are spaced along the ridge line 76. In the electrode layer 28, electrodes are formed, which are connected to both ends of the heat generating resistors 26 to supply currents to the heat generating resistors 26. The protective film 29 covers the glaze layer 25, heat generating resistors 26, and electrode layer 28.

Description

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

  The thermal print head is a printing device having a plurality of heating resistors arranged in a line. These heating resistors are selectively heated by an external signal, and the Joule heat is transmitted to thermal paper, plate-making film photographic paper, or other media, and an image is formed. Various thermal print heads have been developed from the viewpoint of low noise and low running cost. In particular, in distribution applications, smooth printing of paper media is required because barcode printing and the like are performed in large quantities.

  In a thermal printer equipped with a thermal print head, back feeding may be performed after printing, sending out the medium, cutting the medium, etc., and then sending it back to the thermal print head. During this back feed, jamming may occur due to a collision between the medium and the end of the thermal print head.

  Therefore, in various forms of thermal printers, measures have been taken to prevent jamming through adjustments specific to the device. A method for suppressing the occurrence of jamming in the thermal print head itself has also been developed.

JP 2010-240876 A

  In the thermal printer, the medium is printed while being conveyed toward the end of the head substrate. After printing, the device needs to convey the medium to a position where the user takes out the printed medium by a function called a tear-off mode or a peeling mode. After the medium stuck on the film is conveyed and the user takes out the printed medium, the medium that has not been printed is sent back to the printing position again.

  During this back feed operation, the medium to be printed next passes over the thermal print head in the direction opposite to the transport direction during printing. When this medium passes over the thermal print head, the end of the head substrate of the thermal print head collides with the medium, the medium peels off, the medium is damaged, and the load on the mechanism part that performs the feeding operation on the device side May cause problems such as failure due to excessive.

  Thus, for example, Patent Document 1 discloses a method of chamfering an end portion of a head substrate to mitigate an impact caused by a collision between the head substrate and a medium. In this method, since the inclined surface is formed in the portion of the head substrate where the medium comes into contact, the impact is suppressed during printing of the flexible medium. However, if the boundary between the glass heat insulating layer and the protective film is exposed at the end of the head substrate, in the case of a hard medium, the portion may be lost due to collision with the medium.

  Accordingly, an object of the present invention is to suppress the possibility of damage to the end portion of the head substrate of the thermal print head.

  In order to solve the above-described problems, the present invention provides a thermal printing head having a rectangular plate-like ceramic having an upper surface, a slope that is connected to the top surface, is inclined with respect to the top surface, and has a bottom surface that faces the top surface and the slope A substrate, a glaze layer that covers the slope and has a ridge line that is farther from the bottom surface than the top surface; and a glaze layer that extends across the ridge line on the surface of the glaze layer and is arranged at intervals along the ridge line A heating resistor, electrodes connected to both ends of the heating resistor to pass a current through the heating resistor, and a protective film covering the glaze layer, the heating resistor, and the electrode. It is characterized by.

  Further, the present invention provides a thermal printer having a rectangular plate-shaped ceramic substrate having an upper surface, an inclined surface connected to the upper surface and inclined with respect to the upper surface, and a bottom surface facing the upper surface and the inclined surface, and covering the inclined surface And a glaze layer having a ridge line far from the bottom surface than the top surface, a heating resistor extending across the ridge line on the surface of the glaze layer and arranged at intervals along the ridge line, and A thermal print head comprising: an electrode extending in a direction away from the ridge line from both ends of the heating resistor; a protective film covering the glaze layer, the heating resistor, and the electrode; And a medium transport mechanism for transporting in the direction.

  According to the present invention, the possibility of breakage of the end portion of the head substrate of the thermal print head can be suppressed.

1 is a cross-sectional view of an embodiment of a thermal print head according to the present invention. 1 is a partially cut-out top view of an embodiment of a thermal print head according to the present invention. 1 is a cross-sectional view of a thermal printer using an embodiment of a thermal print head according to the present invention. It is sectional drawing for every process of the one part process of the manufacturing method of one Embodiment of the thermal print head concerning this invention.

  An embodiment of a thermal print head according to the present invention will be described with reference to the drawings. Note that this embodiment is merely an example, and the present invention is not limited thereto.

  FIG. 1 is a sectional view of an embodiment of a thermal print head according to the present invention. FIG. 2 is a partially cutaway top view of the thermal print head of the present embodiment. FIG. 3 is a cross-sectional view of a thermal printer using the thermal print head of the present embodiment.

  The thermal print head 11 according to the present embodiment includes a heat radiating plate 30, a head substrate 20, and a circuit substrate 40. The heat sink 30 is a rectangular flat plate made of a metal such as aluminum.

The head substrate 20 has a ceramic substrate 22 and a heat insulating layer 25. The ceramic substrate 22 is a rectangular insulating plate made of alumina (Al ₂ O ₃ ), for example. The ceramic substrate 22 has a bottom surface 70, an upper surface 71, a slope 72, and a tip surface 73. The bottom surface 70 of the ceramic substrate 22 faces the heat sink 30. The upper surface 71 and the front end surface 73 are parallel to the bottom surface 70. The distance between the tip surface 73 and the bottom surface 70 is smaller than the distance between the top surface and the bottom surface 70. The front end surface 73 is a belt-like plane extending along one long side. The upper surface 71 is a belt-like flat surface extending along the long side opposite to the tip surface 73. The inclined surface 72 is a belt-like flat surface sandwiched between the tip surface 73 and the upper surface 71 and extending parallel to the long side, and is inclined with respect to the bottom surface 70.

  The heat insulating layer 25 is fused to the slope 72 of the ceramic substrate 22. The heat insulating layer 25 is not fused to the front end surface 73 and the upper surface 71 of the ceramic substrate 22. That is, the heat insulating layer 25 is provided between the boundary line 74 between the upper surface 71 and the inclined surface 72 of the ceramic substrate 22 and the boundary line 75 between the inclined surface 72 and the tip surface 73.

  The heat insulating layer 25 is made of glass. The surface of the heat insulating layer 25 is a smooth curved surface. The ridgeline 76 farthest from the bottom surface 70 of the surface of the heat insulating layer 25 extends in parallel to the boundary line 74 between the upper surface 71 and the inclined surface 72 of the ceramic substrate 22, that is, in the longitudinal direction (main scanning direction) of the ceramic substrate 22. Yes. The distance between the ridgeline 76 of the heat retaining layer 25 and the bottom surface 70 of the ceramic substrate 22 is larger than the distance between the top surface 71 and the bottom surface 70 of the ceramic substrate 22. The tangent plane of the heat insulating layer 25 at the ridge line 76 is parallel to the bottom surface 70 of the ceramic substrate 22.

  The resistor layer 27 is formed on the surface of the heat insulating layer 25 and the upper surface 71 of the ceramic substrate 22 so as to straddle the ridge line 76 with a space along the main scanning direction, that is, the direction in which the ridge line 76 extends. A metal wiring layer 28 is formed on the surface of the resistor layer 27.

  The metal wiring layer 28 is formed with a notch that straddles the ridge line 76, and the portion of the resistor layer 27 that does not overlap the metal wiring layer 28 becomes the heating resistor 26. In this way, a plurality of heating resistors 26 are arranged on the surface of the ridge line 76 at intervals, and a belt-like heating region 24 along the line of the ridge 21 is formed. An insulating protective film 29 is formed on the head substrate 20 to cover the ceramic substrate 22, the glaze layer 25, the metal wiring layer 28, and the resistor layer. The tip surface 73 of the ceramic substrate 22 and the vicinity of the long side opposite to the tip surface 73 are not covered with the insulating protective film 29.

  Further, the thermal print head 11 has a drive circuit that generates heat in the heat generating region 24. The drive circuit is formed on a circuit board 40 placed on the heat sink 30 on the same surface as the head substrate 20, 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. The drive circuit has electrical components such as a drive element 42 provided on the circuit board 40, for example. The head substrate 20 and the drive circuit are electrically connected by, for example, bonding wires 44 laid between the head substrate 20 and the circuit substrate 40. Further, the wiring pattern formed on the surface of the circuit board 40 and the drive element 42 are also electrically connected by the bonding wire 44. The drive element 42 and the bonding wire 44 are sealed by a sealing resin body 48, for example.

  Next, a method for manufacturing the thermal print head of this embodiment will be described.

  FIG. 4 is a cross-sectional view for each step of some steps of the method of manufacturing the thermal print head in the present embodiment.

  First, a ceramic plate 81 as shown in FIG. Next, as shown in FIG. 4B, the surface of the ceramic plate 81 facing the bottom surface 70 is cut to form a groove 82. Here, a case where two thermal print heads 11 are manufactured from one ceramic plate 81 is described. Both sides of the groove 82 are portions that become the upper surface 71 of the ceramic substrate 22. Further, the side surface of the groove 82 is a portion that becomes the slope 72 of the ceramic substrate 22. At the bottom of the groove 82, a flat portion that forms the tip surface 73 is formed.

Next, as shown in FIG. 4C, a glass paste 83 is printed in the groove 82 portion. The glass paste 83 is obtained by adding a binder and a solvent to glass powder containing, for example, SiO ₂ , Al ₂ O ₃ , BaO or CaO as main components. These are sufficiently mixed with a mixer or the like and then kneaded using a ceramic roll. The glass paste 83 thus obtained is screen-printed on the ceramic plate 81. The glass paste 83 protrudes from the upper surface 71 of the ceramic plate 81.

  Next, as shown in FIGS. 4D to 4F, the glass paste 83 is patterned into a predetermined shape. For example, the photoresist is left on the glass paste 83, and then the glass paste 83 is etched to remove the photoresist to perform patterning. In this patterning, the glass pace 83 remains only on the slope 72 portion so that the vicinity of the portion to be the ridgeline 76 of the heat retaining layer 25 is thickened.

  At the center of the groove 82 of the ceramic plate 81, the glass paste 83 is completely removed so that the ceramic plate 81 is exposed. Since this portion has a particularly deep etching depth, it may be etched, for example, in about three times.

  Thereafter, the heat insulating layer 25 is formed by firing the ceramic plate 81 to which the patterned glass paste 83 is applied. Firing is performed at 1200 ° C. for about 1 to 2 hours, for example.

  Since the glass has fluidity during firing, the vicinity of the boundary of the slope 72 is formed to be convex outward due to surface tension. Moreover, the surface of the heat insulation layer 25 becomes a smooth curved surface by the influence of surface tension. Since glass has a certain degree of viscosity, the difference in height between the upper surface 71 and the portion where the glass paste 83 protrudes from the upper surface 71 remains until after firing. As a result, the ridge line 67 protrudes from the upper surface 71.

  After the heat insulation layer 25 is formed in this manner, the resistor layer 27 and the metal wiring layer 28 are laminated on a part of the ceramic plate 81 and the surface of the heat insulation layer 25 and etched into a predetermined pattern. Further, an insulating protective film 29 is formed. After forming the insulating protective film 29 in this way, the center of the groove 83 is diced and divided into two. Thereby, the two thermal print heads 11 are completed.

  Since the portion where the heat insulating layer 25 at the center of the groove 83 is not formed is diced, the glass heat insulating layer 25 is not cut, and chipping of the heat insulating layer 25 is suppressed. Since a hard material is used as the insulating protective film 29, the insulating protective film 29 is formed on the dicing portion at the center of the groove 82 of the ceramic plate 81 so that it is not necessary to cut the insulating protective film 29 during dicing. It is preferable not to form.

  The printer using the thermal print head 11 has a cylindrical platen roller 50 centering on an axis 52 located on the normal line of the surface of the heat generating area 24. The printing medium 60 is pressed against the thermal print head 11 by the platen roller 50. In this state, the heat generating resistor 26 in the heat generating region 24 generates heat, and the image is printed on the printing medium 60. While the printing medium 60 is conveyed in the sub-scanning direction, the heat generating area 24 extending in the main scanning direction generates heat in a predetermined pattern, so that a desired image is formed on the printing medium 60.

  The print medium 60 is attached to a transport medium 61 such as a film. The transport medium 61 and the print medium 60 are transported back and forth in the sub-scanning direction by the transport mechanism 62. At the time of printing, the transport medium 61 and the print medium 60 attached thereto are sent in the forward direction of the sub-scanning direction.

  When printing on one print medium 60 is completed, the print medium 60 is sent beyond the cutting mechanism 63. In this state, the transport medium 61 is cut.

  After the printed medium 60 is cut by cutting the conveyance medium 61, the medium 60 that has been conveyed to the downstream side in the sub-scanning direction from the heat generation area 24 is sent in the reverse direction (back-feeded). ) As a result, the front end of the print area of the printing medium 60 that is not printed is returned to the heat generation area 24 or the upstream side thereof. Thereafter, printing on the printing medium 60 is performed while the printing medium 60 is conveyed in the forward direction of the conveyance direction together with the conveyance medium 61.

  In the present embodiment, on the downstream side of the heat generating region 24, the surface of the head substrate 20 is a smooth curved slope 77 that descends toward the bottom surface of the ceramic substrate 22. Therefore, the back-fed printing medium 60 is smoothly conveyed upstream along the inclined surface 77. As a result, jamming of the printing medium 60 at the end of the head substrate 20 is suppressed.

  The slope 77 is covered with an insulating protective film 29. For this reason, the printing medium 60 does not collide with a portion where the glass heat insulating layer 25 is exposed. As a result, even if the printing medium 60 is a hard card or the like, the possibility that the end of the head substrate 20 is damaged due to the collision of the printing medium 60 is suppressed.

  Further, since the ridge line 76 of the heat insulating layer 25 protrudes from the upper surface 71 of the ceramic substrate 22, the surface of the head substrate 20 protrudes in the heat generating region 24. For this reason, the linear conveyance direction of the printing medium 60 can be ensured parallel to the bottom surface 70 of the ceramic substrate 22. That is, a straight conveyance path can be secured even for a hard print medium.

  The tangential plane of the surface of the head substrate 20 in the heat generating region 24 is parallel to the bottom surface 70 of the ceramic substrate 22. For this reason, when the shaft 52 of the platen roller 50 is disposed in the normal direction of the heat generating region 24, the position of the head substrate 20 in the direction parallel to the bottom surface 70 may be adjusted. By making the bottom surface of the heat sink 30 parallel to the bottom surface 70 of the ceramic substrate 22, the shaft 52 of the platen roller 50 can be moved along the mounting surface (not shown) of the heat sink 30 by moving the shaft 52 of the platen roller 50. Can be arranged in the normal direction. Therefore, assembly of the thermal print head 11 to the thermal printer is easy.

DESCRIPTION OF SYMBOLS 11 ... Thermal print head, 20 ... Head substrate, 21 ... Projection, 22 ... Ceramic substrate, 24 ... Heat generation area, 25 ... Heat retention layer, 26 ... Heat generation resistor, 27 ... Resistance layer, 28 ... Metal wiring layer, 29 DESCRIPTION OF SYMBOLS ... Insulating protective film, 30 ... Heat sink, 40 ... Circuit board, 42 ... Drive element, 44 ... Bonding wire, 48 ... Sealing resin body, 50 ... Platen roller, 52 ... Shaft, 60 ... Printed medium, 61 ... Conveyance Medium, 70 ... bottom surface, 71 ... top surface, 72 ... slope, 73 ... tip surface, 74 ... boundary line, 75 ... boundary line, 76 ... ridge line, 77 ... slope, 81 ... ceramic plate, 82 ... groove, 83 ... glass paste

Claims (4)

A rectangular plate-shaped ceramic substrate having an upper surface and an inclined surface connected to the upper surface and inclined with respect to the upper surface; and a bottom surface facing the upper surface and the inclined surface;
A glaze layer that covers the slope and has a ridge that is far from the bottom surface than the top surface; and
A heating resistor extending across the ridge line on the surface of the glaze layer and arranged at intervals along the ridge line; and
Electrodes connected to both ends of the heating resistor to pass a current through the heating resistor;
A protective film covering the glaze layer, the heating resistor and the electrode;
A thermal print head comprising:   The thermal print head according to claim 1, wherein the edge of the glaze layer is separated from the one long side. The glaze layer covers at least a part of the upper surface, and the ridge line protrudes from a portion covering the upper surface of the glaze layer,
3. The thermal print head according to claim 1, wherein the heating resistor and the electrode are laminated on a surface of the glaze layer. A rectangular plate-like ceramic substrate having an upper surface and a slope inclined with respect to the upper surface and inclined with respect to the upper surface, and a bottom surface opposite to the upper surface and the slope, and a distance from the bottom surface to the upper surface and covering the slope Has a distant ridge line, a heating layer extending across the ridge line on the surface of the glaze layer and arranged at intervals along the ridge line, from both ends of the heating resistor from the ridge line A thermal print head comprising: an electrode extending in a separating direction; and a protective film covering the glaze layer, the heating resistor, and the electrode;
A medium transport mechanism for transporting the recording medium in the forward and reverse directions;
A thermal printer comprising:

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