JP2012201010A - Thermal head and thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small thermal head.SOLUTION: The thermal head includes: a head substrate with a first bus line formed thereon; a driver IC 120 having a second bus line 139 formed thereon and mounted on the head substrate; and a connection member 135a connecting the first bus line with the second bus line 139. A part of the bus line (second bus line 139) is formed on the driver IC 120, thereby reducing the width of the bus line (first bus line) formed on the head substrate. The size of the driver IC 120 arranged across the first bus line can be reduced, thereby reducing the size of the thermal head.

Description

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

  A thermal printer is known as one of printing apparatuses. The thermal printer has a thermal head in which heating elements are linearly arranged (see, for example, Patent Documents 1 and 2). The heating elements arranged in the thermal head selectively generate heat when energized. The thermal energy selectively reacts with the color former contained in the thermal paper, thereby printing various information on the thermal paper. This printing method is called a thermosensitive coloring method.

JP-A-9-39282 Japanese Patent Laid-Open No. 5-261957

  The thermal head includes a head substrate, a plurality of heating elements arranged on the head substrate, and a plurality of driver ICs for driving the plurality of heating elements. The plurality of driver ICs are arranged along the arrangement direction of the plurality of heating elements. An FPC (flexible circuit board) for supplying a drive signal to the driver IC is connected to the side opposite to the heat generating element across the driver IC. A first bump electrode array for inputting a drive signal from the FPC is formed on one side of the driver IC on the FPC side. A second bump electrode array that outputs a drive signal to the heat generating element is formed on one side of the driver IC on the heat generating element side.

  On the head substrate, bus lines such as data lines extend in parallel with the arrangement direction of the plurality of driver ICs. The plurality of driver ICs are flip-chip mounted on the head substrate so that the first bump electrode array and the second bump electrode array straddle the bus line. For this reason, the size of the driver IC (the distance between the first bump electrode array and the second bump electrode array) cannot be made smaller than the bus line, and the driver IC can be downsized and the thermal head can be downsized. There was a problem that became difficult.

  An object of the present invention is to provide a small thermal head and a thermal printer.

  The thermal head according to the present invention includes a head substrate on which a first bus line is formed, a driver IC on which the second bus line is formed and mounted on the head substrate, the first bus line, and the first bus line. And a connecting member that connects the two bus lines.

  According to this configuration, since a part of the bus line (second bus line) is formed on the driver IC, the width of the bus line (first bus line) formed on the head substrate can be reduced. Can do. Therefore, it is possible to reduce the size of the driver IC arranged across the first bus line, and consequently to reduce the size of the thermal head.

  The driver IC includes a first bump electrode array composed of a plurality of first bump electrodes arranged in parallel with the second bus line, and a plurality of first electrodes arranged in parallel with the second bus line. A second bump electrode array composed of two bump electrodes, and the first bump electrode array and the second bump electrode array are arranged to face each other across the second bus line. Good.

  According to this configuration, the second bus line can be formed in a wide area between the first bump electrode row and the second bump electrode row.

  The head substrate includes a first electrode pad row including a plurality of first electrode pads arranged in parallel to the first bus line, and a plurality of first electrodes arranged in parallel to the first bus line. A second electrode pad row comprising two electrode pads, wherein the first electrode pad row and the second electrode pad row are arranged to face each other across the first bus line, and One electrode pad row and the first bump electrode row may be connected, and the second electrode pad row and the second bump electrode row may be connected.

  According to this configuration, the first bus line can be formed in a wide area between the first electrode pad row and the second electrode pad row.

  The first bump electrode, the second bump electrode, and the connection member may include a resin protrusion and a wiring film that covers a surface of the resin protrusion.

  According to this configuration, the first bump electrode, the second bump electrode, and the connection member can be formed by a common process.

  The wiring film of the first bump electrode, the wiring film of the second bump electrode, and the wiring film of the connecting member may be formed of the same conductive material as that of the second bus line.

  According to this configuration, the second bus line, the first bump electrode, the second bump electrode, and the connection member can be formed by a common process.

  The first electrode pad and the second electrode pad may be formed of the same conductive material as that of the first bus line.

  According to this configuration, the first bus line, the first electrode pad, and the second electrode pad can be formed by a common process.

  The thermal printer of the present invention includes the thermal head of the present invention.

  According to this configuration, a small thermal printer provided with a small thermal head can be provided.

It is a sectional side view of the printer mechanism part which is the principal part of a thermal printer. FIG. 3 is an enlarged view of a printing unit included in a printer mechanism unit. It is an external appearance perspective view of a thermal head. It is a top view of the head substrate of a thermal head. It is a figure explaining the structure of driver IC. It is a bottom view of driver IC.

  Hereinafter, the thermal head of the present embodiment and the thermal printer including the thermal head will be described with reference to FIGS. In all the drawings below, the dimensions and ratios of the constituent elements are appropriately changed in order to make the drawings easy to see. 1 to 6, the X direction is the width direction of the thermal paper to be printed, the Z direction is the paper feed direction of the thermal paper in the thermal head unit, and the Y direction is the X direction and the Z direction. It is a direction orthogonal to the direction.

  FIG. 1 is an explanatory diagram showing a thermal printer 100 according to the present embodiment, and is a side sectional view showing a side section of a printer mechanism unit 300 that is a main part of the thermal printer 100. FIG. 2 is an enlarged view of the printing unit 70 included in the printer mechanism unit 300.

  As shown in FIG. 1, the printer mechanism unit 300 is provided with a main body frame 60 that accommodates the roll paper R, a cover frame 10, a roll paper holder 30, and the thermal head 1 of the present invention. A printing unit 70 that prints on the drawn thermal paper S, and a paper cutting unit 20 that is provided behind the printing unit 70 in the paper feeding direction and cuts the printed thermal paper S for each predetermined printing unit. Yes.

The thermal paper S has a printing surface composed of a coloring layer in which a coloring agent is held by a binder or the like. In the thermal printer 100, the thermal paper S is stored inside as a roll paper R wound up in a roll shape with the printing surface as an outer surface, and is sent to the printing unit 70 (thermal head 1) while being pulled out and printed. The
Hereinafter, each configuration of the printer mechanism unit 300 will be described along the paper feeding direction of the thermal paper S.

  The main body frame 60 is formed in a box shape having an opening on the upper side, and the cover frame 10 is provided above the main body frame 60 so as to cover the opening of the main body frame 60. A roll paper holder 30 is provided inside the main body frame 60.

  The cover frame 10 is attached so as to be openable and closable around a support shaft 68 provided at one end portion above the main body frame 60. The cover frame 10 is provided with an arcuate lid portion 15 for avoiding contact with the roll paper R when the cover frame 10 is closed. The lid 15 also functions as a holding member that receives the roll paper R when the installation angle of the thermal printer 100 is changed, that is, for example, when the thermal printer 100 is placed vertically.

  The roll paper holder 30 is formed of resin or the like. The roll paper holder 30 has a substantially arc-shaped depression corresponding to the maximum diameter of the roll paper R at the center, and is attached to the bottom of the main body frame 60 so that the substantially arc-shaped depression protrudes downward. It has been.

  When the roll paper R is arranged in the roll paper holder 30 provided in this way, the roll paper holder 30 holds the roll paper R in a rotatable manner. At the same time, both side surfaces on the inner side of the main body frame 60 function as side surface guide portions of the roll paper R to restrict the movement of the roll paper R in the width direction.

  As shown in FIG. 2, the printing unit 70 holds the thermal head 1, a platen 71 provided so as to be opposed to the thermal head 1 and in which the thermal paper 1 is in close contact with the thermal head 1, and the thermal head 1. And a head holding mechanism 77 that biases 1 toward the platen 71.

  The thermal head 1 includes a head substrate (substrate) 110 provided with a plurality of heating elements for printing on the thermal paper S, and a heat radiating plate 106 that is provided in close contact with the head substrate 110 and radiates heat accumulated in the head substrate 110. And a head support shaft 102 provided on the side surface of the heat radiating plate 106 and an FPC 108 connected to the head substrate 110 for inputting signals. Details of the thermal head 1 will be described later.

  The platen 71 is formed in a cylindrical roller shape by an elastic member such as rubber and is rotatably supported by the cover frame 10 via a platen bearing 73. Further, a paper feed mechanism (not shown) for rotating the platen 71 is provided on the side surface of the main body frame 60. The paper feed mechanism (not shown) is connected to the platen bearing 73 in a state where the cover frame 10 is closed. Drive to rotate. Thus, when the platen 71 rotates, the thermal paper S is transported downstream of the transport path D.

  The head holding mechanism 77 includes a head pressing plate 72 and a spring 75 having one end fixed to the head pressing plate 72 and the other end contacting the back surface of the thermal head 1. The cutout portion 62 is detachably provided.

  The spring 75 fixed to the head pressing plate 72 is in contact with the back surface of the thermal head 1 and biases the thermal head 1 toward the platen 71. Thereby, the thermal head 1 presses the thermal paper S in the direction of the platen 71 from the printing surface S1 side. On the other hand, the platen 71 presses the thermal paper S in the direction of the thermal head 1 from the back surface S2. As a result, the thermal paper S is sandwiched between the thermal head 1 and the platen 71. The thermal paper S is printed by the thermal head 1, and the printed thermal paper S is transported downstream of the transport path D as the platen 71 rotates.

Returning to FIG. 1, the paper cutting unit 20 includes a movable blade 21, a fixed blade 24 provided to face the movable blade 21, and a fixed blade cover 25 that covers the fixed blade 24. It is provided at the paper exit G through which the thermal paper S after printing passes. In the paper cutting part 20, the thermal paper S is cut | disconnected by the movable blade 21 and the fixed blade 24 crossing in scissors shape.
The thermal printer 100 of the present embodiment has the schematic configuration as described above.

(About thermal head)
Next, the thermal head 1 will be described with reference to FIGS. 3 and 4. FIG. 3 is an external perspective view of the thermal head. 4A and 4B are plan views of the head substrate of the thermal head, in which FIG. 4A is an overall view of the head substrate, and FIG. 4B is a partially enlarged view of FIG.

  As shown in FIG. 3, the thermal head 1 includes a heat dissipation plate 106, a head support shaft 102, a head substrate 110 as a substrate, a driver IC 120, and an FPC 108. The head substrate 110 has a long rectangular shape, and a heating element array 145a including a plurality of heating elements 145 is formed in the Z direction upward in the drawing along the longitudinal direction. A plurality of driver ICs 120 for driving the heat generating elements 145 are arranged in parallel with the heat generating element rows 145a. The heat radiating plate 106 is formed of a drawing material such as aluminum, and the head substrate 110 is attached to the locking surface 106a of the heat radiating plate 106 with a double-sided adhesive tape or the like.

  Above the heat sink 106 in the Z direction of the head substrate 110, a guide slope 104 is formed across the length of the heat sink 106. When the cover slope 10 shown in FIG. 1 is closed, the guide slope portion 104 slides the platen 71 to guide it to a predetermined position. At this time, the inclination of the guide slope portion 104 has a predetermined angle so that the platen 71 does not collide with the head substrate 110. In addition, the slope of the guide slope 104 is set to be substantially the same height as the head substrate 110 attached in the vicinity of the guide slope 104. The head support shaft 102 is a cylindrical round pin, and is press-fitted into holes provided in the left and right side portions of the heat radiating plate 106.

  Here, the head substrate will be described with reference to FIG. As shown in FIG. 4A, the head substrate 110 is made of alumina ceramic or the like, and is a linear heating element 140 that converts an energized current into heat along a longitudinal direction at a position near the one side edge 110a. Are linearly provided in a state protected by a protective film. On the other side edge 110b of the head substrate 110, a plurality of external connection terminals 112 are provided for electrical connection with the outside. A common wiring pattern 114 is formed in a belt-like region between the heating element 140 and one side edge 110a of the head substrate 110. Both ends of the common wiring pattern 114 are extended to the external connection terminal 112. At substantially the center of the head substrate 110, an IC mounting portion 120a for mounting the driver IC 120 is provided for each driver IC 120, and arranged in a row parallel to the linear heating elements 140.

  As shown in FIG. 4B, a comb-like common electrode 114a is extended from the common wiring pattern 114, and on the other hand, it is inserted between the comb-like common electrodes 114a. One end of the electrode 118 is extended. The other end portion of each individual electrode 118 extends to an IC mounting portion 120a provided on the head substrate 110, and a first electrode pad 115 as a mounting terminal is formed at the end portion. The electrode pad 115 corresponds to each heating element 145 described later. In the present embodiment, the mounted driver IC 120 can pass a current through the individual electrodes 118 corresponding to the heating elements 145 for 128 bits per one, for example. Therefore, at least 128 electrode pads 115 are formed. The 128 or more electrode pads 115 are formed in a straight line and constitute a first electrode pad row 115a as a first mounting terminal row.

  A second electrode pad 116 as a mounting terminal is formed on the other side edge 110b side of the head substrate 110 of the IC mounting portion 120a. The electrode pad 116 is electrically connected to the external connection terminal 112 shown in FIG. The external connection terminal 112 is attached with an FPC 108 (see FIG. 3), and is connected to a main circuit board (not shown) constituting a control unit that controls the thermal printer 100 via the FPC 108. An input signal such as print data, a drive current, and the like are input from the control unit of the thermal printer 100. Therefore, for example, dozens of electrode pads 116 are formed. The dozen electrode pads 116 are formed in a straight line and constitute a second electrode pad row 116a as a second mounting terminal row.

  As shown by a two-dot chain line in FIG. 4B, the heating element 140 is formed so as to overlap the comb-like common electrode 114a and the individual electrode 118 entering between them. Therefore, the heating element 145 is defined by the adjacent comb-shaped common electrode 114a and the individual electrode 118. That is, when the selected individual electrode 118 is turned on by a driver IC 120, which will be described later, a current flows through the heating element 140 in a region surrounded by the individual electrode 118 and the comb-like common electrode 114a. It functions as a heating element 145.

  In the thermal head 1, when the heating elements 140 in the respective areas are selectively energized, only the heating elements 140 in the energized areas instantaneously generate heat. 106 is configured to dissipate heat. Further, the heating element 140 is disposed in the vicinity of the contact point between the platen 71 that sandwiches and conveys the thermal paper S and the thermal head 1. Therefore, the heat energy generated from the heating element 140 is transmitted to a region corresponding to the heating element 145 of the thermal paper S.

(About driver IC)
Here, the driver IC will be described with reference to FIGS. 5A and 5B are diagrams illustrating the structure of the driver IC. FIG. 5A is a cross-sectional view of the connection terminal portion, FIG. 5B is a view of the connection terminal portion viewed from the bottom surface of the driver IC, and FIG. FIG. 6 is a perspective view of the connection terminal portion as viewed obliquely from above in FIG. FIG. 6 is a bottom view of the driver IC.

  The driver IC 120 is an IC chip in which, for example, a drive circuit for the thermal head 1 is appropriately formed on a silicon substrate 120b as a semiconductor chip. An electrode 124 made of aluminum or the like is formed on the active surface 120c of the driver IC 120. The electrodes 124 are arranged along the long side portion of the driver IC 120. A protective film 126 such as a passivation film made of an insulating material such as SiN is formed on the surface of the electrode 124. The opening 127 formed in the protective film 126 constitutes an electrical connection portion 132 that connects the electrode 124 and a wiring film 130 described later.

  Resin protrusions 131 are formed on the surface of the protective film 126. The resin protrusion 131 is continuously formed along the arrangement direction (arrow X direction) of the electrodes 124 by coating an elastic resin material such as polyimide on the surface of the protective film 126 and performing a patterning process such as photolithography. Is done. The resin protrusion 131 has a step between a region where the wiring film 130 is formed and a region where the wiring film 130 is not formed. Furthermore, the resin protrusion 131 is formed so that the cross-sectional shape taken along the line ff in FIG. 5B orthogonal to the arrangement direction of the electrodes 124 becomes a substantially semicircular shape.

  In addition to the polyimide resin, the resin protrusion 131 may be made of silicone-modified polyimide resin, epoxy resin, silicone-modified epoxy resin, acrylic resin, phenol resin, silicone resin, modified polyimide resin, benzocyclobutene, polybenzoxazole, etc. A resin may be used.

  Further, a wiring film 130 is formed on the surface of the resin protrusion 131. The wiring film 130 is formed by depositing a conductive metal such as Au, TiW, Cu, Ni, Pd, Al, Cr, Ti, W, NiV, lead-free solder or the like by vapor deposition or sputtering, and applying an appropriate patterning process. It is formed by doing. Further, the surface of the underlying wiring film 130 made of Cu, Ni, Al or the like can be further covered with Au plating or the like to enhance the conductive contact property. The wiring film 130 has a substantially rectangular shape in plan view, and is disposed from the electrical connection portion 132 over the resin protrusion 131 to the surface of the protective film 126 on the opposite side.

  A bump electrode 135 as a connection terminal having a substantially semicircular cross section is formed on the protective film 126 of the driver IC 120 by the resin protrusion 131 and the wiring film 130 configured as described above.

  As shown in FIG. 6, the bump electrodes 135 are formed in a row along the long side of the active surface 120c of the driver IC 120, and the first bump electrode row 137a and the second connection electrode row as the first connection terminal row. A second bump electrode row 137b is formed as a connection terminal row. The first bump electrode row 137a includes a plurality of first bump electrodes 135a as at least 128 connection terminals that are electrically connected to the electrode pads 115 conducted to the 128 heat generating elements 145 shown in FIG. The bump electrode 135 is made up of.

  The second bump electrode array 137b is electrically connected to the electrode pad 116 that is electrically connected to the external connection terminal 112 shown in FIG. 4 to which an input signal such as print data, a drive current, or the like is input. It is composed of a second bump electrode 135b as a terminal. In other words, the first bump electrode row 137a and the second bump electrode row 137b having extremely different numbers of bump electrodes 135a and 135b are formed on the active surface 120c of the driver IC 120.

  The driver IC 120 and the head substrate 110 are connected as follows. First, in the IC mounting part 120a of the head substrate 110, an insulating adhesive film (not shown) is disposed so as to cover the first electrode pad row 115a and the second electrode pad row 116a. Next, the bump electrodes 135 a of the driver IC 120 are aligned with the electrode pads 115 of the head substrate 110, and the bump electrodes 135 b of the driver IC 120 are aligned with the electrode pads 116 of the head substrate 110. Then, the driver IC 120 is pressed toward the head substrate 110, and the resin protrusion 131 is crushed and elastically deformed, and the wiring film 130 of the resin protrusion 131 is secured to the electrode pads 115 and 116 of the head substrate 110 with a sufficient contact area. Make contact. Thereafter, the insulating adhesive film is cured, and the connection state between the head substrate 110 and the driver IC 120 is fixed.

  Here, in the thermal head 1 of this embodiment, as shown in FIGS. 4B and 6, the bus lines for supplying data to the plurality of driver ICs 120 are the first bus line 119 and the second bus line 139. It is divided into and. The first bus line 119 is formed on the surface of the head substrate 110 on which the electrode pads 115 and 116 are formed, and the second bus line 139 is formed on the active surface 120c of the driver IC 120.

  The first bus line 119 extends in parallel with the arrangement direction (X direction) of the plurality of driver ICs 120 so as to overlap the plurality of driver ICs 120. The first bus line 119 is formed along the gap between the first electrode pad row 115a and the second electrode pad row 116a, and both ends of the first bus line 119 are connected to the external connection terminal 112. It is extended all the way. The first electrode pad row 115a and the second electrode pad row 116a are disposed to face each other with the first bus line 119 interposed therebetween. The first bus line 119 is connected to two electrode pads 115 provided at both ends of the first electrode pad row 115a among the plurality of electrode pads provided in the IC mounting portion 120a. The electrode pad 115 connected to the first bus line 119 is not connected to the heating element 140.

  The second bus line 139 is formed along the gap between the first bump electrode row 137a and the second bump electrode row 137b. Both ends of the second bus line 139 are connected to two bump electrodes 135 provided at both ends of the first bump electrode row 137a among the plurality of bump electrodes 135 provided on the active surface 120c. . The first bump electrode row 137a and the second bump electrode row 137b are disposed to face each other with the second bus line 139 interposed therebetween. The bump electrode 135 connected to the second bus line 139 is connected to the electrode pad 115 connected to the first bus line 119. The bump electrode 135 connected to the second bus line 139 functions as a connecting member that connects the first bus line 119 and the second bus line 139.

  The electrode pad 115 and the electrode pad 116 are formed by a common process using the same conductive material as that of the first bus line 119. The wiring film 130 of the bump electrode 135 is formed by a common process using the same conductive material as that of the second bus line 139.

  In the thermal head 1 configured as described above, a part of the bus line (second bus line 139) is formed on the driver IC 120, so that the bus line (first bus line 119) formed on the head substrate 110 is formed. The width of can be reduced. Therefore, the driver IC 120 disposed across the first bus line 119 can be downsized, and the thermal head 1 and the thermal printer 100 can be downsized.

DESCRIPTION OF SYMBOLS 1 ... Thermal head, 100 ... Thermal printer, 110 ... Head substrate, 115 ... 1st electrode pad (connection member), 115a ... 1st electrode pad row | line | column, 116 ... 2nd electrode pad, 116a ... 2nd electrode Pad row, 119 ... first bus line, 120 ... driver IC, 130 ... wiring film, 131 ... resin protrusion, 135a ... first bump electrode, 135b ... second bump electrode, 137a ... first bump electrode row 137b ... second bump electrode array, 139 ... second bus line

Claims (7)

A head substrate on which a first bus line is formed;
A driver IC formed with a second bus line and mounted on the head substrate;
A thermal head comprising: a connecting member that connects the first bus line and the second bus line.   The driver IC includes a first bump electrode array composed of a plurality of first bump electrodes arranged in parallel with the second bus line, and a plurality of first electrodes arranged in parallel with the second bus line. A second bump electrode array including two bump electrodes, and the first bump electrode array and the second bump electrode array are arranged to face each other across the second bus line. Item 2. The thermal head according to Item 1.   The head substrate includes a first electrode pad row including a plurality of first electrode pads arranged in parallel to the first bus line, and a plurality of first electrodes arranged in parallel to the first bus line. A second electrode pad row comprising two electrode pads, wherein the first electrode pad row and the second electrode pad row are arranged to face each other across the first bus line, and 3. The thermal head according to claim 2, wherein one electrode pad row and the first bump electrode row are connected, and the second electrode pad row and the second bump electrode row are connected.   4. The thermal head according to claim 3, wherein the first bump electrode, the second bump electrode, and the connection member include a resin protrusion and a wiring film that covers a surface of the resin protrusion. 5.   5. The wiring film of the first bump electrode, the wiring film of the second bump electrode, and the wiring film of the connection member are formed of the same conductive material as the second bus line. The thermal head described.   The thermal head according to claim 5, wherein the first electrode pad and the second electrode pad are formed of the same conductive material as that of the first bus line.   The thermal printer provided with the thermal head of any one of Claims 1-6.

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