JP2005238663A - Thermal head and thermal printer having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high performance thermal head capable of being miniaturized and a thermal printer. <P>SOLUTION: This thermal head comprises a head substrate 1 having a plurality of heating elements 2 and a circuit conductor 3 electrically connected to the heating elements 2, and a flexible wiring board 4 having a plurality of wiring conductors 5, the one end side of the flexible wiring board 4 being provided along the edge of the head substrate 1. In the thermal head, the wiring conductors 5 are electrically connected to the circuit conductor 3 at one end side of the flexible wiring board 4. The flexible wiring board 4 has a protruding section 13 positioned on a portion at the outside of the head substrate 1 in a direction along the edge of the head substrate 1 and the protruding section 13 is folded to the upper or lower face side of the flexible wiring board 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a thermal head that performs a recording operation using heat generated by a heating element, and a thermal printer using the same.

  Conventionally, a thermal head has been used as a printer mechanism such as a word processor. For example, as shown in FIGS. 8 and 9, the conventional thermal head includes a plurality of heating elements 22 on the upper surface and circuit conductors 23 such as a common electrode conductor 23a and individual electrode conductors 23b connected to both ends of the heating element 22. A flexible printed circuit board 24 (hereinafter abbreviated as FPC) having a plurality of wiring conductors 25 electrically connected to the circuit conductor 23 of the head substrate 21; And a support member 30 that supports the head substrate 21 and the FPC 24 on the upper surface with an adhesive 27 interposed therebetween.

  The FPC 24 is used to supply various print signals (driver IC control signals) from the printer main body and power from an external power source to the heating elements 22 and the driver IC 29, and between a plurality of flexible resin films. And a wiring conductor 25 made of copper foil or the like. The wiring conductor 25 of the FPC 24 is connected to the common electrode conductor 23a of the head substrate 21, and is connected to the power supply power conductor 25a for supplying power to the heating element 22 and the individual electrode conductor 23b on the head substrate 21 in the driver IC. A signal wiring conductor 25b for supplying a signal for driving and controlling the driver IC connected via a switching element, and a ground connected to the individual electrode conductor 23b of the head substrate 21 via a ground terminal in the driver IC. It is comprised with the wiring conductor 23b.

The electrical connection between the head substrate 21 and the FPC 24 is, for example, by solder welding, in which a part of the wiring conductor 25 exposed on one end side of the FPC 24 is overlapped along the end portion of the head substrate 21. This superposition is performed by soldering the wiring conductor and the circuit conductor 23 on the head substrate 21 together.
JP 2001-334696 A JP 2000-177159 A

  By the way, in recent thermal heads, with the miniaturization of printers, there is an increasing demand for miniaturization of thermal heads, and accordingly, miniaturization of the FPC 24, particularly the direction along the end of the head substrate 21. It is desired to reduce the size in a direction perpendicular to (a sub-scanning direction in the case of this prior art).

  On the other hand, with the recent increase in the density of heating elements, the pattern of the wiring conductor 25 of the FPC 24 tends to become complicated, and there is a problem that it is difficult to downsize the FPC 24 in the sub-scanning direction.

  Further, among the wiring conductors 25 of the FPC 24, the power wiring conductor 25a connected to the common electrode conductor 23a on the head substrate 21 flows a relatively large current, and voltage drop tends to be a problem. However, in this case, there is a problem that the thermal head is enlarged due to the space of the power supply wiring conductor 25a.

  The present invention has been devised in view of the above problems, and an object thereof is to provide a high-performance thermal head and a thermal printer capable of downsizing the thermal head.

  The thermal head of the present invention has a head substrate having a plurality of heating elements and circuit conductors electrically connected to the heating elements, and a plurality of wiring conductors, and one end side is at the end of the head substrate. And a flexible wiring board disposed along the thermal head, wherein the flexible wiring board is electrically connected to the circuit conductor on the one end side of the flexible wiring board. It has a protruding portion located outside the head substrate in the direction along the end portion, and the protruding portion is folded back to the upper surface side or the lower surface side of the flexible wiring substrate.

  The thermal head of the present invention is characterized in that, in the above-described thermal head, at least a part of the wiring conductor is arranged in the protruding portion.

  Furthermore, the thermal head of the present invention is the above-described thermal head, wherein a connector for electrically connecting the wiring conductor to an external electric circuit is attached to the other end side of the flexible wiring board and the folded back. The protruding portion is attached to the connector.

  Furthermore, the thermal head of the present invention is the above-described thermal head, wherein the circuit conductor includes a common electrode conductor commonly connected to the heating element and an individual electrode conductor individually connected to the heating element. It is characterized by that.

  Furthermore, the thermal head of the present invention is the above-described thermal head, wherein the wiring conductor includes at least a power wiring conductor electrically connected to the common electrode conductor, and the power wiring conductor is disposed in the protruding portion. Features.

  A thermal printer according to the present invention includes the above-described thermal head and a transport unit that transports a recording medium onto the thermal head.

  According to the present invention, the protruding portion located outside the head substrate in the direction along the end portion of the head substrate is formed on the flexible wiring substrate, and the protruding portion is formed on the upper surface side or the lower surface side of the flexible wiring substrate. Because it is folded, a part of the wiring board is placed on the protruding part, so that the flexible wiring board can be downsized in the direction perpendicular to the end of the head substrate without increasing the size in the direction along the end of the head substrate. can do.

  Further, according to the present invention, a connector for electrically connecting the wiring conductor to an external electric circuit is attached to the other end of the flexible wiring board, and the folded over portion is connected to the connector. By attaching the protrusions, it is possible to satisfactorily fix the folded-back protruding portion.

  Furthermore, according to the present invention, among the wiring conductors of the flexible wiring board, the power supply wiring conductor connected to the common electrode conductor on the head substrate is provided at the protruding portion of the flexible wiring board, so that a large current is applied to the voltage. It is possible to easily increase the area of the power wiring conductor, which is likely to cause a drop, and to reduce the wiring resistance of the power wiring conductor. Moreover, it is possible to suppress an increase in the size of the thermal head due to the increase in the area of the power supply wiring conductor, thereby realizing a small thermal head with low power consumption.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

  1 is a plan view of a thermal head according to an embodiment of the present invention, FIG. 2 is a cross-sectional view thereof, and FIG. 3 is a plan view of the thermal head of FIG. 1 when a protruding portion of an FPC (flexible wiring board) is developed. It is. The thermal heads shown in these drawings are roughly composed of a head substrate 1, an FPC 4 connected to the head substrate 1, a connector 6 attached to the FPC 4, and a support member 10 that supports the head substrate 1. It is configured.

  The head substrate 1 can be formed of various materials such as an insulating material such as alumina ceramic or a semiconductor material such as single crystal silicon having an insulating film formed on the surface, and the heating element 2 and the circuit conductor 3 are provided on the upper surface thereof. It is provided and functions as a support base material that supports them.

  When the head substrate 1 is made of alumina ceramics, for example, an appropriate organic solvent or solvent is added to and mixed with ceramic raw material powders such as alumina, silica, and magnesia to form a slurry, and this is made into a conventionally known doctor blade method or calendar. A ceramic green sheet is formed by adopting a roll method or the like, and thereafter, the ceramic green sheet is punched into a predetermined shape and fired at a high temperature.

  On the head substrate 1, a plurality of heating elements 2, a plurality of circuit conductors 3 and the like arranged in a straight line are respectively attached.

  The heating elements 2 are linearly arranged in the main scanning direction along one side of the head substrate 1 at a density of 300 dpi, for example, and are made of an electric resistance material such as TaSiO, TiSiO, TaSiNO, TaN, and the like. Therefore, when energized power from an external power source is applied through a circuit conductor 3 electrically connected to the heating element 2, Joule heat is generated, and a print image is printed on the thermal recording medium. It acts to generate heat at a predetermined temperature required for forming, for example, 200 ° C. to 350 ° C.

  The circuit conductor 3 connected to the heating element 2 includes, for example, a common electrode conductor 3a commonly connected to one end side of the heating element 2 and an individual electrode conductor 3b individually connected to the other end side of the heating element 2. And is composed of. The common electrode conductor 3a is formed in a U shape so that a part thereof is arranged substantially in parallel with the arrangement of the heating elements 2, and both ends thereof are set to a predetermined positive potential (for example, 20V) via the wiring conductor 5 of the FPC 4. Connected to the positive terminal of the external power source held at ~ 25V). Further, one end of the individual electrode conductor 3b is connected to the switching element and ground terminal of the driver IC 9 and the negative terminal of the external power source held at the ground potential (for example, 0V to 2V) via the wiring conductor 5 of the FPC 4. When the switching element of the driver IC 9 is turned on, a current flows from the common electrode conductor 3a to the individual electrode conductor 3b, and the heating element 2 generates heat at a predetermined temperature.

  The heating element 2 and the circuit conductor 3 are deposited on the head substrate 1 in a predetermined pattern and a predetermined thickness by employing a conventionally known sputtering method and photolithography technique. On the heating element 2 and the circuit conductor 3, a protective film 8 for covering them is attached.

  The head substrate 1 is connected to an FPC 4 for supplying various print signals from the printer main body and power from an external power source to the heating element 2 and the driver IC 9.

  On the other hand, the FPC 4 connected to the head substrate 1 is electrically connected to the circuit conductor 3 on the head substrate 1 between a plurality of flexible resin films (formed of a resin material such as polyimide resin). The connection portion 11 is connected to the circuit conductor 3 on the head substrate 1 via a conductive material such as solder or an anisotropic conductive resin material. A pair of protrusions 13 located on the outer side of both ends of the head substrate 1 in the direction along the end of the head substrate 1 with the connector portion 12 into which the connector pins of the connector 6 are inserted on the other side. On both sides.

  Since a part of the wiring conductor 5 is arranged in the protruding portion 13 of the FPC 4, a space near the center necessary for the arrangement of the wiring conductor 5 can be omitted as compared with the conventional FPC 4. The size can be reduced in a direction orthogonal to the direction along the end (in the present embodiment, the sub-scanning direction).

  The protruding portion 13 is folded back to the upper surface side or the lower surface side (upper surface side in the present embodiment) of the FPC 4, and the folded portion is inserted into the connector pin of the connector 6. Therefore, it is possible to prevent the thermal head from becoming large in the direction along the end portion of the head substrate 1 and to fix the folded over protruding portion 13 satisfactorily.

  In this embodiment, since the protruding portion of the FPC 4 is folded and the folded portion is inserted into the connector pin of the connector 6, the FPC 4 is overlapped in the attachment region of the connector 6, and the connector 6 is stably It will be attached to FPC4. Therefore, it is easy to attach and detach the external connection member provided on the printer side with respect to the connector 6. In addition, if an adhesive is filled between the protruding portion 13 of the FPC 4 inserted into the connector pin and the FPC 4, the strength of the FPC 4 is further increased, and there is no need to add a reinforcing plate such as an epoxy resin. is there.

  Further, the wiring conductor 5 of the FPC 4 is, for example, an individual electrode on the head substrate 1 via a power wiring conductor 5a connected to the common electrode conductor 3a on the head substrate 1 and a strobe signal terminal or a data signal terminal of the driver IC 9. The signal wiring conductor 5b connected to the conductor 3b and the ground wiring conductor 5b connected to the individual electrode conductor 3b on the head substrate 1 via the ground terminal of the driver IC 9 are configured.

  Among these wiring conductors 5, the power wiring conductor 5 a that is electrically connected to the common electrode conductor 3 a through which a large current flows from the external power source is disposed in the protruding portion 13, and the power wiring conductor 5 a of the protruding portion 13 is connected to the connector 6. Electrical connection is made to the connector pins. For this reason, it is possible to easily increase the area of the power supply wiring conductor 5a, which is likely to cause a voltage drop due to a large current flow, and to reduce the wiring resistance of the power supply wiring conductor 5a. Moreover, it is possible to suppress an increase in the size of the thermal head due to the increase in the area of the power supply wiring conductor, thereby realizing a small thermal head with low power consumption.

  The connector 6 connected to the other end side of the FPC 4 has a structure in which a part of the connector pin is accommodated in the housing, and when an external connection member (not shown) on the printer side is inserted into the housing, The thermal head is electrically connected to an electric circuit in the printer.

  The electrical connection between the connector 6 and the FPC 4 is made by inserting a connector pin into a land 15 with a hole provided in the FPC 4 and connecting the connector pin to the FPC 4 with a conductive material such as solder while the connector pin penetrates the FPC 4. It is fixed to the wiring conductor 5.

  The support member 10 on which the head substrate 1 is placed supports the head substrate 1 and the FPC 4 on the upper surface thereof, and absorbs part of the heat in the head substrate 1 through the lower surface of the head substrate 1. This effectively prevents the temperature of the head substrate 1 from becoming excessively high.

  Such a support member 10 is manufactured, for example, by forming an ingot (lumb) such as aluminum into a predetermined shape by a conventionally known metal processing method.

  In order to complete the head assembly by bonding the FPC 4 to the head substrate 1 with a conductive material (for example, solder bonding) and placing the FPC 4 on the support member 10, a method through the following steps is adopted (see FIG. 4). ).

  Step 1: A land 15 for soldering the connector 6 to the connector portion 12 and the protruding portion 13 of the FPC 4 is provided (FIG. 4A).

  Step 2: The protruding portion of the FPC 4 is bent upward by 180 ° so as to face the main surface of the FPC 4 in the vicinity of the connecting portion 11, and then the connector 6 is soldered to the FPC 4. In the present embodiment, of the connector pins, the outer two pins are inserted into the protruding portion 13 and the remaining six pins are inserted into the connector portion 12 and soldered (FIG. 4B).

  Step 3: The connecting portion 11 of the FPC is overlapped along the end portion of the head substrate 1, and the wiring conductor 5 is brought into contact with the circuit conductor 3 via the solder at the overlapping portion, and then this is used with a heater bar. Then, the circuit conductor 3 and the wiring conductor 5 are electrically connected to the head substrate 1 by being melted at a predetermined temperature and soldered (FIG. 4C).

  Step 4: A part of the head substrate 1 and the FPC 4 are bonded to the upper surface of the support member 10 made of a heat-conductive material such as aluminum via an adhesive 7 such as a double-sided tape or an adhesive (FIG. 4D). ).

  Thus, the thermal head described above selectively heats each heat generating element 2 based on the driving of the driver IC 9 while conveying the recording medium onto the plurality of heat generating elements 2 and uses the heat to the recording medium. Transmit a predetermined image.

  In the thermal printer in which the above-described thermal head is incorporated, as shown in FIG. 5, the driving means C for driving the thermal head T, the external connection member (not shown), and the recording medium are heated by the thermal head T. A platen roller 17, a transport roller 18, and the like are disposed as transport means for transporting onto the element 2.

  The external connection member is for electrically connecting the thermal printer and the above-described thermal head, and is usually made of the same material as the connector 6 having a shape corresponding to the connector member 6 by a predetermined external force ( An external connector (for example, made of nylon) is preferably used, and both connectors are connected when the thermal head T is assembled in the thermal printer.

  At this time, even if a large force is applied to the connector 6 in the insertion direction of the external connection member, the protruding portion 13 of the FPC 4 is overlapped in the attachment region of the connector 6, so that the FPC 4 is relatively at the overlapping portion. Becomes difficult to bend. Therefore, the connection work between the thermal head T and the printer body is simplified, and the productivity of the thermal printer can be improved.

  On the other hand, the platen roller 17 as a conveying means is a cylindrical member in which butadiene rubber or the like is wound around the outer periphery of a shaft core made of a metal such as SUS to a thickness of about 3 mm to 15 mm, and the heating element 2 of the thermal head T. The recording medium is conveyed in a direction orthogonal to the arrangement of the heating elements 2 (in the direction of the arrow in the figure) while being rotatably supported above and pressing the recording medium against the heating elements 2.

  The outer periphery of the conveying roller 18 is formed of metal, rubber, or the like, and is arranged separately from the thermal head T on the upstream side and the downstream side in the recording medium conveying direction. The platen roller 17 supports the running of the recording medium.

  At the same time, a large number of heat generating elements 2 are selectively joule-heated as the driving means C is driven, and a predetermined print is formed by conducting these heats to the recording medium.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the gist of the present invention.

  For example, in the above-described embodiment, the protruding portion 13 is folded back to the upper surface side of the FPC 4, but instead, the protruding portion 13 may be folded back to the lower surface side of the FPC 4 as shown in FIG. good.

  In the above-described embodiment, the head substrate 1 and the FPC 4 are electrically connected by soldering or the like. Instead, as shown in FIG. 7, the head substrate 1 and the FPC 4 are bonded by bonding wires or the like. You may make it connect.

  In the above-described embodiment, the protruding portions 13 are provided on both sides of the FPC 4. However, the protruding portions 13 may be provided only on one side.

  Furthermore, in the above-described embodiment, the protruding portion of the FPC 4 is folded once, but this may be folded back multiple times.

It is a top view of the thermal head concerning one Embodiment of this invention. It is sectional drawing of the thermal head concerning one Embodiment of this invention. FIG. 2 is a plan view of the thermal head of FIG. 1 when an FPC protrusion is developed. (A)-(d) is explanatory drawing of the assembly process of the thermal head concerning one Embodiment of this invention. FIG. 2 is a schematic side view of a thermal printer configured by incorporating the thermal head of FIG. 1. It is sectional drawing of the thermal head concerning other embodiment of this invention. It is sectional drawing of the thermal head concerning other embodiment of this invention. It is a top view of the conventional thermal head. It is sectional drawing of the conventional thermal head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Head substrate 2 ... Heating element 3 ... Circuit conductor 3a ... Common electrode conductor 3b ... Individual electrode conductor 4 ... FPC
5 ... wiring conductor 5a ... power supply wiring conductor 5b ... signal wiring conductor, ground wiring conductor 6 ... connector 7 ... adhesive 9 ... driver IC
DESCRIPTION OF SYMBOLS 10 ... Support member 11 ... FPC connection part 12 ... FPC connector part 13 ... FPC protrusion part 15 ... Land 17 ... Platen roller 18 ... Conveyance roller

Claims (6)

A head substrate having a plurality of heating elements and a circuit conductor electrically connected to the heating elements, and a flexible wiring board having a plurality of wiring conductors and having one end side disposed along the end of the head substrate In a thermal head comprising a wiring board, and electrically connecting the wiring conductor to the circuit conductor on the one end side of the flexible wiring board,
The flexible wiring board has a protruding portion located outside the head substrate in the direction along the end of the head substrate, and the protruding portion is folded back to the upper surface side or the lower surface side of the flexible wiring substrate. Characteristic thermal head. The thermal head according to claim 1, wherein at least a part of the wiring conductor is disposed in the protruding portion. A connector for electrically connecting the wiring conductor to an external electric circuit is attached to the other end side of the flexible wiring board, and the folded-out portion is attached to the connector. The thermal head according to claim 1 or 2. The said circuit conductor is provided with the common electrode conductor connected to the said heat generating element in common, and the individual electrode conductor connected individually to the said heat generating element, The Claim 1 thru | or 3 characterized by the above-mentioned. The thermal head described in 1. The thermal head according to claim 4, wherein the wiring conductor includes at least a power wiring conductor electrically connected to the common electrode conductor, and the power wiring conductor is arranged in the protruding portion. 6. A thermal printer comprising: the thermal head according to claim 1; and a transport unit that transports a recording medium onto the thermal head.

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