JP4659411B2 - Thermal head and thermal printer using this thermal head - Google Patents

Description

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

  Conventionally, a thermal head has been used as a printer mechanism such as a word processor. For example, as shown in FIGS. 7 and 8, the conventional thermal head includes a head substrate in which a plurality of heating elements 22 and circuit conductors 23 connected to both ends of the heating elements 22 are formed on an upper surface of a rectangular substrate 21. The wiring board 24 having a plurality of wiring conductors 25 electrically connected to the circuit conductors 23 of the head board via the joints 28, the rectangular substrate 21 and the wiring board 24 are connected via an adhesive 31. And a support member 30 supported on the upper surface.

  The wiring board 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 heat generating element 22 and the driver IC 26, and has a plurality of flexibility. A wiring conductor 25 made of copper foil or the like is interposed between resin films.

The electrical connection between the circuit conductor 23 of the rectangular substrate 21 and the wiring conductor 25 of the wiring substrate 24 is, for example, made of conductive resin, and the wiring conductor 25 exposed at the tip end on one end side of the wiring substrate 24. Is overlapped along the end portion of the rectangular substrate 21 and the wiring conductor and the circuit conductor 23 on the rectangular substrate 21 are bonded by thermocompression at the overlapping portion.
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 wiring board 24, especially along the end of the head board 21. It is desired to reduce the size in the direction orthogonal to the direction (in the case of this prior art, the sub-scanning direction).

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

  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.

A thermal head of the present invention, a rectangular substrate, heat generating elements one arranged on the end side of the該矩shape on the substrate, along with are provided in the rectangular substrate, arranged at the other end of the該矩shape on the substrate And a circuit conductor for supplying a current to the heating element, and a circuit conductor for supplying a current to the heating element, and a region between the heating element and the junction on the rectangular substrate, are electrically connected to the circuit conductor, the head substrate having a driver IC for controlling the heating of the heating element, having a plurality of wiring conductors, the wiring conductor is arranged at the other end on the rectangular substrate A wiring board electrically connected to the circuit conductor by being joined at the joined part , and one end of the wiring board extends to the heating element side with respect to the joining part. The rectangular substrate and the arrangement in the existing area The substrate overlaps, and in the extending region, a part of the plurality of wiring conductors including at least a ground wiring conductor connected to a ground terminal of the driver IC is disposed, The driver IC is covered with the extended region.

Furthermore the thermal head of the present invention is characterized in that the extending region of the wiring board is inclined to be close to the upper surface of the rectangular substrate closer to the heating element.

Furthermore the thermal head of the present invention also includes the extending region of the wiring board is characterized in that it has secured by a resin adhesive member to the rectangular substrate.

  Furthermore, the thermal head of the present invention has a cable for inputting a signal to the wiring board, which is fixed to the wiring board on one end side of the cable and detachable on the other end side of the cable. Is provided.

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

  According to the thermal head of the present invention, the rectangular substrate, the heat generating element arranged on one end side of the upper surface of the rectangular substrate, the heat generating element arranged on the other end side of the rectangular substrate, and the heat generating element In a thermal head comprising a head substrate having a circuit conductor for supplying a signal for controlling an element and a wiring substrate having a wiring conductor, the circuit conductor and the wiring conductor are arranged on the other end side of the rectangular substrate. Electrically connected, and one end of the wiring board extends to the heat generating element side with respect to a connection portion between the circuit conductor and the wiring conductor, and the rectangular board and the Since the wiring substrate overlaps, the thermal head can be reduced in size in the direction orthogonal to the arrangement direction of the heat generating elements by the extended region, which can contribute to the downsizing of the thermal head.

  According to the thermal head of the present invention, the driver IC that selectively generates heat from the heating element is mounted on the upper surface of the rectangular substrate so as to be covered with the extension region of the wiring substrate, so that the recording medium is thermally The driver IC can be protected from static electricity and mechanical shock generated when sliding on the head.

  Furthermore, according to the thermal head of the present invention, since the extending region of the wiring board is inclined so as to be closer to the upper surface of the rectangular substrate as it approaches the heating element, the recording medium is rectangular from the upper surface of the wiring substrate. It is guided smoothly and substantially continuously to the upper surface of the shape substrate, and the recording medium has little fluttering, and a desired print can be formed on the recording medium.

  Furthermore, according to the thermal head of the present invention, since the extension region of the wiring board is fixed to the rectangular board with a resin adhesive member, the wiring board and the wiring board are connected only to the other end side of the rectangular board. Mechanical bonding can be made stronger than when the substrate is bonded.

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

  FIG. 1 is a perspective view of a thermal head according to an embodiment of the present invention, and FIG. 2 is a sectional view thereof. The thermal head shown in these drawings includes a head substrate, a wiring substrate 4 connected to the head substrate, a cable 12 attached to the wiring substrate 4, and a support member 10 that supports the head substrate. ing.

  The head substrate is provided with a heating element 2, a circuit conductor 3, and the like on the upper surface thereof. The rectangular substrate 1 serving as the base of the head substrate can be formed of various materials such as an insulating material such as alumina ceramics or a semiconductor material such as single crystal silicon having an insulating film formed on the surface.

  When the rectangular substrate 1 is made of alumina ceramic, for example, an appropriate organic solvent or solvent is added to and mixed with ceramic raw material powder such as alumina, silica, magnesia, etc. to form a slurry, and this is made into a conventionally known doctor blade method or A ceramic green sheet is formed by adopting a calendar 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 rectangular 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 end of the rectangular substrate 1 at a density of 300 dpi or 600 dpi, for example, and are made of an electrical resistance material such as TaSiO, TiSiO, TaSiNO, TaN, Since it itself has a predetermined electrical resistivity, Joule heat is generated when energized power from an external power source is applied through a circuit conductor 3 electrically connected to the heat generating element 2, and a thermal recording medium. In this case, heat is generated at a predetermined temperature necessary for forming a printed image, 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 individually connected to the other end side of the heating element 2. 3b. 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 the wiring substrate 4 to which both ends thereof are connected on the other end side of the rectangular substrate 1 is formed. Is connected to a positive terminal of an external power source held at a predetermined positive potential (for example, 20 V to 25 V) via the wiring conductor 5. The individual electrode conductor 3b has one end at a ground potential (for example, 0 V to 2 V) via the switching element and ground terminal of the driver IC 6 and the wiring conductor 5 of the wiring substrate 4 connected on the other end side of the rectangular substrate 1. Connected to the negative terminal of the held external power supply. When the switching element of the driver IC 6 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 in a predetermined pattern and a predetermined thickness by employing a conventionally known sputtering method and photolithography technique.

  The driver ICs 6 that control the heat generation of the heating elements 2 are arranged in a line on the other end side of the rectangular substrate 1. The driver IC 6 has an integrated circuit in which a shift register, a latch, a switching element, an input terminal, an output terminal, and the like are integrated at a high density on one main surface of a silicon substrate.

  The driver IC 6 inputs the image data from the wiring board 4 to the shift register through the input terminal while synchronizing with the clock signal, and stores the input image data in the latch at the timing of the latch signal. Is supplied to the switching element, the heating element 2 is energized based on the image data in the latch.

  The above-described driver IC 6 is manufactured by employing a conventionally well-known semiconductor manufacturing technique, and the obtained driver IC 6 is connected to the output terminal and the individual electrode conductor 3b by a conventionally well-known wire bonding method or face-down bonding method. It is mounted on the rectangular substrate 1 by being electrically connected.

  Such a driver IC 6 is sealed with a sealing resin 7 made of a resin material such as a thermosetting epoxy resin.

  The sealing resin 7 is formed so that the cross section thereof is convex, and protects the driver IC 6 from corrosion due to moisture contained in the atmosphere, and an extension region of the wiring board 4 described later is formed on the recording medium. Even when the platen roller is bent due to the sliding contact, the driver IC 6 is well protected by supporting the wiring board 4 from below.

  For the sealing resin 7, a predetermined liquid precursor made of, for example, an epoxy resin is applied so as to cover the driver IC 6 on the head substrate, and this is heated and polymerized at a high temperature (130 ° C. to 150 ° C.). Formed by.

  Further, a wiring board 4 for supplying various printing signals from the printer main body and power from an external power source to the heating element 2 and the driver IC 6 is joined to the rectangular board 1 on the other end side of the rectangular board 1. It is fixed at part 8.

  The wiring substrate 4 bonded to the rectangular substrate 1 is electrically connected to the circuit conductor 3 on the rectangular substrate 1 between a plurality of resin films that can be bent (formed of a resin material such as polyimide resin). It has a structure in which a plurality of wiring conductors 5 are interposed.

  In this wiring board 4, one end of the wiring board 4 extends to the heat generating element 2 side with respect to the connecting portion between the rectangular board 1 and the wiring board 4, and the rectangular board 1 and the wiring board are extended in this extending region. 4 are superimposed. Therefore, the thermal head can be reduced in size in the direction orthogonal to the arrangement direction of the heat generating elements 2 by the extension region of the wiring board 4, which can contribute to miniaturization of the thermal head and the thermal printer. Therefore, it is desirable to extend the wiring board 4 to the heat generating element 2 as much as possible.

  However, it is necessary that the extension of the wiring board 4 is stopped before the nip region where the thermal head is pressed by the platen roller. This is because if the leading end of the wiring board 4 reaches the nip region of the platen roller, the wiring conductor 4 is wound when the recording medium is transported, and vibration due to this winding may occur.

  By the way, the extension area of the wiring board 4 is located on the heating element 2 side of the mounting area of the driver IC 6, so that the extension area covers the driver IC 6.

  Therefore, the driver IC 6 can be protected from static electricity and mechanical shock generated when the recording medium slides on the thermal head.

  Further, since the extended region is inclined so that the tip thereof is closer to the upper surface of the rectangular substrate 1 as it approaches the heating element 2, the recording medium is moved from the upper surface of the wiring substrate 4 to the upper surface of the rectangular substrate 1. Thus, it is possible to prevent the recording medium from fluttering due to a high step existing when the extending region of the wiring substrate 4 is separated from the upper surface of the rectangular substrate 1. As a result, a desired print can be formed on the recording medium. More preferably, the end of the extended region of the wiring board 4 is in contact with the upper surface of the rectangular substrate 1.

  Further, in this extended region, a second bonding portion 9 is provided in which the head substrate and the wiring substrate 4 are bonded with resin.

  The second bonding portion 9 can increase the mechanical strength as compared with the case where the rectangular substrate 1 and the wiring substrate 4 are fixed only by the bonding portion 8 on the other end side of the rectangular substrate 1. The second joint portion 9 may be provided in several places in some places, or may be provided over a wide area of the extension area.

  Incidentally, a part of the wiring conductor 5 is disposed in the extending region of the wiring board 4. As the wiring conductor 5 disposed in the extension region of the wiring substrate 4, a signal in which signals having the same contents are inputted in parallel to a plurality of driver ICs 6 mounted on the rectangular substrate 1, for example, a clock signal, A signal wiring conductor for supplying a latch signal, a strobe signal, etc., a ground wiring conductor connected to the ground terminals of the plurality of driver ICs 6, a common electrode conductor, and the like are disposed.

  Further, the wiring board 4 is provided with a cable 12 that is electrically and mechanically connected through, for example, a conductive resin, solder, or the like. The cable 12 has one end fixed to the wiring board 4 and the other end provided with a detachable electrical connecting portion 16 such as a connector. The other end is connected to an electric circuit of the printer main body. It is connected. As a result, an unreasonable force is applied to the wiring board 4 when the thermal head is attached to or removed from the thermal printer, as in the case where the detachable electrical connection portion 15 such as a connector is provided directly on the wiring board 4. Therefore, the mechanical reliability of the thermal head can be prevented from being impaired.

  The support member 10 on which the rectangular substrate 1 is placed supports the rectangular substrate 1 on its upper surface and absorbs part of the heat in the rectangular substrate 1 through the lower surface of the head substrate. It effectively prevents the temperature of the thermal head from becoming excessively high. An adhesive 7 is applied to the upper surface of the support member 10, and the rectangular substrate 1 is fixed by the adhesive 7.

  Thus, the thermal head described above selectively heats each of the heating elements 2 based on the driving of the driver IC 6 while conveying the recording medium onto the plurality of heating elements 2, and the heat is transferred to the recording medium. Transmit a predetermined image.

  In the thermal printer in which the thermal head as described above is incorporated, as shown in FIG. 4, the driving means C for driving the thermal head T and the conveying means for conveying the recording medium onto the heating element 2 of the thermal head T are used. A platen roller 13 and a conveying roller 14 are disposed.

  The platen roller 13 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 is placed on the heating element 2 of the thermal head T. The recording medium is conveyed in a direction (arrow direction in the drawing) orthogonal to the arrangement of the heating elements 2 while being rotatably supported and pressing the recording medium against the heating elements 2.

  The outer periphery of the conveying roller 14 is formed of metal, rubber, or the like, and is arranged separately from the thermal head T in the recording medium conveying direction on the upstream side and the downstream side. The platen roller 13 supports the running of the recording medium.

  At the same time, a plurality 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.

  The present invention is not limited to the above-described embodiments, and various changes and improvements can be made without departing from the scope of the present invention.

  For example, in the above-described embodiment, the wiring substrate 4 covers the driver IC 6 placed on the upper surface of the rectangular substrate 1, but instead of this, as shown in FIGS. A through hole 16 corresponding to the driver IC 6 may be provided, and the wiring board 4 may be superimposed on the rectangular substrate 1 so that the driver IC 6 is accommodated in the through hole 16.

  In this way, the step of bending the wiring board 4 is not necessary, and the elasticity caused by bending the wiring board 4 is applied to the rectangular substrate 1 through the joint between the wiring substrate 4 and the rectangular substrate 1. Therefore, the flatness of the rectangular substrate 1 can be maintained, whereby heat transfer from the heating element to the recording medium can be made uniform, and a higher quality image can be obtained.

  Further, in the above-described embodiment, the common electrode conductor 3a and the wiring conductor 5 are electrically joined only on the other end side of the head substrate, but instead, the position is directly below the extension region of the wiring substrate 4. The common electrode conductor 3a and the wiring conductor 5 may be electrically joined at a plurality of locations of the common electrode conductor 3a.

  As a result, the current path between the common electrode conductor 3a and the wiring conductor 5 is expanded, for example, and a voltage drop inside these conductors can be suppressed.

It is a perspective view of the thermal head concerning one Embodiment of this invention. It is sectional drawing of the thermal head of FIG. It is a top view of the thermal head of FIG. It is a schematic sectional drawing of the thermal printer of this invention. It is sectional drawing of the thermal head concerning other embodiment of this invention. It is a top view of the thermal head of FIG. It is sectional drawing of the conventional thermal head. It is a top view of the conventional thermal head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rectangular substrate 2 ... Heat generating element 3 ... Circuit conductor 3a ... Common electrode conductor 3b ... Individual electrode conductor 4 ... Wiring board 5 ... Wiring conductor 6 ... Driver IC
7 ... sealing resin 8 ... joint 9 ... second joint 10 ... support member 11 ... adhesive 12 ... cable 13 ... platen roller 14 ... transport Roller 16 ... through hole

Claims (5)

Rectangular substrate, heat generating elements one arranged on the end side of the該矩shape on the substrate, along with are provided in the rectangular substrate, electrically to the junction arranged at the other end of the該矩shape on the substrate And a circuit conductor for supplying a current to the heating element, and disposed in a region between the heating element and the joint on the rectangular substrate , and electrically connected to the circuit conductor A head substrate connected and having a driver IC for controlling heat generation of the heating element;
A plurality of wiring conductors, the wiring conductor, and a said circuit conductor electrically connected to the wiring board by being joined by being arranged at the other end on the rectangular substrate the joint ,
One end of the wiring board extends to the heat generating element side from the joint, and the rectangular board and the wiring board overlap in the extending region,
In the extended region, a part of the plurality of wiring conductors including at least a ground wiring conductor connected to a ground terminal of the driver IC is disposed,
The thermal head, wherein the driver IC is covered by the extended region.   2. The thermal head according to claim 1, wherein the extending area of the wiring board is inclined so as to be closer to the upper surface of the rectangular substrate as the heating element approaches.   The thermal head according to claim 1, wherein the extended region of the wiring board is fixed to the rectangular substrate with a resin adhesive member.   The cable for inputting a signal to the wiring board is fixed to the wiring board on one end side of the cable, and a detachable electrical connection portion is provided on the other end side of the cable. The thermal head according to any one of 1 to 3.   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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