JP2011152757A - Connection structure of driver ic wiring - Google Patents

Abstract

A signal is accurately transmitted to a driver IC.
A plurality of input terminals 63 of a driver IC 61 mounted on a COF 51 and a connection terminal 72 of a plurality of input wirings 71 formed on an FPC 52 connected to the COF 51 have the same length. They are connected by a plurality of bonding wires 81. The bonding wire 81b connected to the drive waveform signal input wiring 71b for inputting the drive waveform signal has a loop height from the COF 51 higher than that of the bonding wire 81a connected to the power supply input wiring 71a connected to the power supply. The bonding wire 81c connected to the data signal input wiring 71c for inputting the ejection data signal indicating the ejection timing of the ink from the nozzle and the clock input wiring 71d for inputting the clock is increased. The loop height is higher than that of the wire 81b.
[Selection] Figure 5

Description

  The present invention relates to a wiring connection structure of a driver IC including a driver IC and a wiring connected to the driver IC.

  In the ink jet printer head described in Patent Document 1, an FPC (Flexible Printed Circuit) is disposed on the upper surface of the piezoelectric actuator. A driver IC (driving IC chip) is mounted on the surface of the FPC, an input side wiring drawn from the driver IC to the opposite side of the piezoelectric actuator, and an output side wiring drawn from the driver IC to the piezoelectric actuator side Is formed. Further, the FPC (Flexible Flat Cable) is connected to the end of the FPC opposite to the piezoelectric actuator, whereby the input side wiring is connected to the wiring on the FFC.

  Here, the input side wiring includes a wiring for connecting the driver IC and the power source, a wiring for transmitting a recording data signal and a clock to the driver IC, and the output side wiring is generated in the driver IC. Wiring for transmitting the drive signal of the piezoelectric actuator is included.

JP 2007-83707 A

  Here, in an inkjet printer, it is conceivable to increase the number of nozzles in order to realize printing at a high resolution. In this case, the number of output-side wirings is increased as the number of nozzles increases. There is a need.

  However, in this case, since a large number of output-side wirings and input-side wirings are arranged on one FPC, the interval between the input-side wiring and the output-side wiring is reduced. As a result, for example, A relatively low voltage signal such as a recording data signal or a clock transmitted through the input side wiring is likely to be affected by noise from a relatively high voltage drive signal transmitted through the output side wiring.

  Therefore, the inventor of the present application considered that the input-side wiring is not formed on the FPC, and the wiring on the FFC and the driver IC are connected via a bonding wire (wire bonding).

  However, even in this case, since a magnetic flux is generated around the output wiring due to the current flowing through the output wiring, a signal or clock of recording data transmitted through the bonding wire may be affected by the magnetic flux. .

  In addition, since it is necessary to arrange terminals and circuits as compactly as possible in the driver IC, the distance between the input terminals connected to the bonding wires of the driver IC is the connection terminal of the wiring connected to the bonding wires of the FFC. It becomes narrower than the interval. For this reason, when the connection terminal of the wiring on the FFC and the dormitory terminal of the driver IC are connected via the bonding wire, the length of the bonding wire may vary. In such a case, when the recording data signals corresponding to the plurality of nozzles are input to the driver IC, the timing at which the signals are input varies, and as a result, the ejection timing of the ink from the nozzles varies. There is a risk of variations.

  An object of the present invention is to provide a wiring connection structure of a driver IC capable of inputting an accurate signal to the driver IC.

A wiring connection structure of a driver IC according to a first invention includes a first wiring board, a driver IC mounted on the first wiring board, and having a plurality of input terminals for input and output terminals for output, A plurality of output wirings formed on the first wiring board and each having a plurality of output wirings connected to the output terminal of the driver IC and a connection terminal for connecting the input terminal of the driver IC. And a plurality of bonding wires that connect the input terminals of the driver IC and the connection terminals of the plurality of input wirings,
The interval between the input terminals is narrower than the interval between the connection terminals of the plurality of input wires, and the plurality of input wires transmit a plurality of types of signals having different susceptibility to noise. Bonding wires connected to the plurality of types of signal input wirings have the same length and have different loop heights from the first wiring board. In addition, the bonding wire connected to the connection terminal of the signal input wiring that transmits a signal that is easily affected by noise has a higher loop height.

  When the driver IC and a plurality of input wirings are connected on the first wiring board, when the number of input wirings and output wirings increases, the input wirings and the output wirings are densely arranged on the first wiring board. As a result, the drive signal transmitted through the output wiring is likely to generate noise in the signal transmitted through the input wiring.

  However, in the present invention, since a plurality of input wirings and a driver IC are connected by a plurality of bonding wires, it is possible to prevent noise from being generated in a signal transmitted through the input wirings.

  Further, since the plurality of bonding wires connected to the signal input wiring for transmitting a plurality of types of signals have the same length, the plurality of types of signals are input from the signal input wiring to the driver IC. It is possible to prevent variations in timing.

  Even if a plurality of input wires and driver ICs are connected by a plurality of bonding wires, the signal transmitted through the bonding wires is affected by the magnetic flux generated by the current flowing through the output wires, and the bonding wire loops. The lower the height, that is, the closer the bonding wire is to the output wiring, the more susceptible to the influence of the magnetic flux, and the easier it is to generate noise in the transmitted signal.

  However, in the present invention, the bonding wire through which a signal susceptible to noise is transmitted has a higher loop height, so that the occurrence of noise in the signal susceptible to noise is minimized. Can do.

The driver IC wiring connection structure according to the second invention is the driver IC according to the first invention.
In this wiring connection structure, the plurality of input wirings are formed on a second wiring board different from the first wiring board.

  When the input wiring is formed on a second wiring board different from the first wiring board on which the driver IC is mounted, the input wiring and the driver IC are connected via the wiring on the first wiring board. If this is the case, the impedance at the connecting portion between the input wiring and the wiring on the first wiring board is greatly increased, so that the signal transmitted through the input wiring may be greatly attenuated due to the increase in the impedance. is there.

  However, in the present invention, since the plurality of input wirings on the second wiring board and the driver IC are connected by the plurality of bonding wires, the impedance greatly increases as described above between the input wiring and the driver IC. Therefore, it is possible to prevent the signal transmitted through the input wiring from being greatly attenuated.

  The wiring connection structure of the driver IC according to the third invention is the wiring connection structure of the driver IC according to the first or second invention, wherein the driver IC ejects droplets from a plurality of nozzles. For driving the head, the plurality of types of signal input wirings input a clock input wiring for inputting a clock and a signal of ejection data indicating timing of ejecting droplets from the plurality of nozzles. And a drive waveform signal input for inputting a drive waveform signal corresponding to a drive signal for driving the droplet discharge head, which is output from the output terminal of the driver IC. The loop height of the bonding wire connected to the connection terminal of the clock input wiring and the ejection data signal input wiring, Higher than the loop height of the bonding wire connected to the connection terminals of the dynamic waveform signal input lines and it said.

  According to this, it is possible to suppress as much as possible the occurrence of noise in the ejection data signal and clock that are susceptible to noise.

  A wiring connection structure of a driver IC according to a fourth invention is the wiring connection structure according to any one of the first to third inventions, wherein the plurality of input wirings further include power input wirings connected to a power source. The bonding wires connected to the connection terminals of the power input wiring have the same length as the bonding wires connected to the connection terminals of the plurality of types of signal input wirings, and these bonding wires The loop height is lower than that of the wire.

  According to this, it is possible to suppress as much as possible the occurrence of noise in an input signal whose voltage is lower than that of the power source and is easily affected by noise. In addition, since the bonding wire connected to the power input wiring and the bonding wire connected to the signal input wiring have the same length, all the bonding wires using only one type of wire having the same length. Can be formed.

  According to a fifth aspect of the present invention, there is provided a wiring connection structure of a driver IC, a liquid droplet ejecting head that ejects liquid droplets from a plurality of nozzles, a first wiring substrate connected to the liquid droplet ejecting head, and the first wiring substrate. And a plurality of input terminals for input and output terminals for output, a driver IC for driving the droplet ejection head, and formed on the first wiring board, A plurality of output wirings connected to the output terminal of the driver IC, a plurality of input wirings each having a connection terminal for connection to the input terminal, the input terminal of the driver IC and the plurality of input wirings A plurality of bonding wires connecting the connection terminals, and the plurality of nozzles form a plurality of nozzle rows arranged along one direction, and the driver IC The spacing between the force terminals is narrower than the spacing between the connection terminals of the plurality of input wirings, and the plurality of input wirings are a plurality of odd-numbered nozzle rows counted from one side in the one direction. A plurality of first ejection data signal input wirings for inputting ejection data signals indicating ejection timing of droplets from the nozzles, and a plurality of nozzles constituting an even-numbered nozzle row counted from one side in the one direction A plurality of second ejection data signal input wirings for inputting ejection data signals indicating ejection timing of droplets from the plurality of bonding wires, wherein the plurality of bonding wires are the plurality of first ejection data signal input wirings. A plurality of first wires connected to the connection terminals, and a plurality of second wires connected to the connection terminals of the plurality of second ejection data signal input wirings. Ya is has the same length with each other, the plurality of second wires, characterized in that it has the same length with each other.

  When the droplet ejection head has a plurality of nozzle rows, in order to prevent so-called crosstalk, the ejection timing of droplets from the plurality of nozzles constituting the odd-numbered nozzle rows and the even-numbered nozzle rows In such a case, in the present invention, the droplets corresponding to the plurality of nozzles constituting the odd-numbered nozzle row are shifted in this case. Variation occurs in the timing at which the ejection data signal is input and the timing at which the droplet ejection data corresponding to the plurality of nozzles constituting the even-numbered nozzle row is input to the driver IC. Can be prevented.

  A wiring connection structure of a driver IC according to a sixth aspect of the present invention includes a first wiring board, a driver IC mounted on the first wiring board and having a plurality of input terminals for input and output terminals for output, A plurality of output wirings formed on the first wiring board and connected to the output terminals of the driver IC; and a plurality of input wirings each having a connection terminal for connection to the input terminal; And a plurality of bonding wires for connecting the input terminals of the driver IC and the connection terminals of the plurality of input wirings, and the interval between the input terminals is narrower than the interval between the plurality of input wiring terminals. The plurality of bonding wires have the same loop height from the first wiring board.

  When the driver IC and the plurality of input wirings are connected on the first wiring board, when the number of input wirings and output wirings increases, the input wirings and the output wirings are concentrated on the first wiring board. As a result, the drive signal (current) transmitted through the output wiring is likely to generate noise in the signal transmitted through the input wiring.

  However, in the present invention, since a plurality of input wirings and a driver IC are connected by a plurality of bonding wires, it is possible to prevent noise from being generated in a signal transmitted through the input wirings.

  Also, the signal transmitted through the bonding wire is affected by the magnetic flux generated by the current flowing through the output wiring, but the lower the bonding wire loop height, that is, the bonding wire is closer to the output wiring. The more likely it is to be affected by the magnetic flux, the more likely the noise will be generated in the transmitted signal. For this reason, if the loop heights of a plurality of bonding wires are varied, there is a possibility that the noise generated in the signal input from the bonding wires to the driver IC may vary.

  However, in the present invention, since the loop heights of the plurality of bonding wires are the same, it is possible to prevent variations in noise generated in signals transmitted through the bonding wires.

  A wiring connection structure for a driver IC according to a seventh aspect is the wiring connection structure for a driver IC according to the sixth aspect, wherein the plurality of input wirings are different from the first wiring board. It is formed above.

  When the input wiring is formed on a second wiring board different from the first wiring board on which the driver IC is mounted, the input wiring and the driver IC are connected via the wiring on the first wiring board. If this is the case, the impedance at the connecting portion between the input wiring and the wiring on the first wiring board is greatly increased, so that the signal transmitted through the input wiring may be greatly attenuated due to the increase in the impedance. is there.

  However, in the present invention, since the plurality of input wirings on the second wiring board and the driver IC are connected by the plurality of bonding wires, the impedance greatly increases as described above between the input wiring and the driver IC. Therefore, it is possible to prevent the signal transmitted through the input wiring from being greatly attenuated.

  According to the present invention, since a plurality of input wirings and a driver IC are connected by a plurality of bonding wires, it is possible to prevent noise from being generated in a signal transmitted through the input wirings.

  Furthermore, since a plurality of bonding wires connected to a plurality of types of signal input wirings for transmitting different types of signals have the same length, the plurality of types of signals are transmitted from the signal input wiring to the driver IC. It is possible to prevent the occurrence of variations in the timing at which is input.

1 is a schematic configuration diagram of a printer according to a first embodiment. It is a top view of the inkjet head of FIG. FIG. 3 is a partially enlarged view of FIG. 2. It is the IV-IV sectional view taken on the line of FIG. It is the elements on larger scale of FIG. It is the figure which looked at FIG. 5 from the direction of arrow VI. It is a figure equivalent to FIG. 4 of 2nd Embodiment. It is a figure equivalent to FIG. 5 of 2nd Embodiment.

[First Embodiment]
Hereinafter, a preferred first embodiment of the present invention will be described.

  FIG. 1 is a schematic configuration diagram of a printer according to the first embodiment. As shown in FIG. 1, the printer 1 includes a carriage 2, an ink jet head 3 (droplet ejecting head), a paper transport roller 4, and the like.

  The carriage 2 reciprocates in the scanning direction (left and right direction in FIG. 1) along the guide shaft 5. The inkjet head 3 is attached to the lower surface of the carriage 2 and ejects ink droplets from a plurality of nozzles 15 (see FIG. 2) formed on the lower surface. The paper transport roller 4 transports the recording paper P in the paper feed direction (front side in FIG. 1).

  In the printer 1, printing is performed on the recording paper P by ejecting ink droplets from the inkjet head 3 that reciprocates in the scanning direction together with the carriage 2 onto the recording paper P that is transported in the paper feeding direction by the paper transporting roller 4. I do.

  Next, the inkjet head 3 will be described. FIG. 2 is a plan view of the inkjet head 3. FIG. 3 is a partially enlarged view of FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. As shown in FIGS. 2 to 4, the inkjet head 3 includes a flow path unit 31 in which an ink flow path such as a pressure chamber 10 and a nozzle 15 described later is formed, and a piezoelectric actuator disposed on the upper surface of the flow path unit 31. 32.

  The flow path unit 31 is formed by stacking the cavity plate 21, the base plate 22, the manifold plate 23, and the nozzle plate 24. Here, among these four plates 21 to 24, the three plates 21 to 23 excluding the nozzle plate 24 are made of a metal material such as stainless steel, and the nozzle plate 24 is made of a synthetic resin material such as polyimide. Or the nozzle plate 24 may also be comprised with the metal material similar to the other three plates 21-23.

  A plurality of pressure chambers 10 are formed in the cavity plate 21. The planar shape of the pressure chamber 10 is a substantially ellipse whose longitudinal direction is the scanning direction (left-right direction in FIG. 2). The plurality of pressure chambers 10 are arranged in the paper feeding direction to form one pressure chamber row 8, and such pressure chamber rows 8 are arranged in four rows in the paper feeding direction. Yes. The base plate 22 is formed with substantially circular through holes 12 and 13 at both ends of the pressure chambers 10 in the longitudinal direction.

  A manifold channel 11 is formed in the manifold plate 23. The manifold channel 11 extends in the paper feed direction in the portion facing the substantially right half of the plurality of pressure chambers 10 constituting each pressure chamber row 8, and the portions extending in the paper feed direction are illustrated in FIG. 2 are connected to each other at the lower end. Ink is supplied to the manifold channel 11 from an ink supply port 9 provided at the lower end in FIG. Further, a substantially circular through hole 14 is formed in the manifold plate 23 at a portion facing each through hole 13.

  In the nozzle plate 24, nozzles 15 are formed at portions facing the respective through holes 14, and these nozzles 15 are arranged in the paper feeding direction, like the pressure chambers 10, so that one nozzle row 7 is arranged. At the same time, such nozzle rows 7 are arranged in four rows in the scanning direction.

  In the flow path unit 31, the manifold flow path 11 communicates with the pressure chamber 10 via the through hole 12, and the pressure chamber 10 communicates with the nozzle 15 via the through holes 13 and 14. Yes. As described above, the flow path unit 31 is formed with a plurality of individual ink flow paths from the outlet of the manifold flow path 11 to the nozzle 15 via the pressure chamber 10.

  The piezoelectric actuator 32 includes a vibration plate 41, a piezoelectric layer 42, a plurality of individual electrodes 43, and the like. The vibration plate 41 is made of a metal material such as stainless steel, and is joined to the upper surface of the cavity plate 21 so as to cover the plurality of pressure chambers 10.

  The piezoelectric layer 42 is made of a piezoelectric material mainly composed of lead zirconate titanate, which is a mixed crystal of lead titanate and lead zirconate, and continuously on the upper surface of the vibration plate 41 across the plurality of pressure chambers 10. Is formed. In addition, the piezoelectric layer 42 is polarized in the thickness direction at a portion facing each pressure chamber 10.

  The plurality of individual electrodes 43 are individually formed on the upper surface of the piezoelectric layer 42 with respect to the plurality of pressure chambers 10. Each individual electrode 43 has a substantially elliptical planar shape that is slightly smaller than the pressure chamber 10, and is disposed so as to face the substantially central portion of each pressure chamber 10. Further, the right end portion of each individual electrode 43 in FIG. 2 extends to a portion that does not face the pressure chamber 10, and the tip portion thereof serves as a connection terminal 43a. A land 44 is formed on the upper surface of the connection terminal 43a, and an output wiring 62 (to be described later) of a COF (Chip On Film) 51 (first wiring board) is connected to the land 44. The electrode 43 is connected to the driver IC 61 via the output wiring 62 as will be described later. A drive voltage (drive signal) is applied to the individual electrode 43 by the driver IC 61 via the output wiring 62 and the land 44.

  The conductive diaphragm 41 is connected to a surface electrode (not shown) formed on the upper surface of the piezoelectric layer 42 through a through hole (not shown) formed in the piezoelectric layer 42. Further, the driver IC 61 is connected via a land (not shown) formed on the upper surface thereof and an output wiring 62 formed on the COF 51. The diaphragm 41 is always held at the ground potential by the driver IC 61, and also serves as a common electrode when driving the piezoelectric actuator 32.

  Here, before describing the COF 51, a method of driving the piezoelectric actuator 32 will be described. In the piezoelectric actuator 32, the plurality of individual electrodes 43 are previously held at the ground potential. When a driving potential is applied to any of the individual electrodes 43 by the driver IC 61, a potential difference is generated in a portion of the piezoelectric layer 42 sandwiched between the individual electrode 43 and the diaphragm 41 as a common electrode. As a result, an electric field in the thickness direction is generated in this portion of the piezoelectric layer 42. Since the direction of the electric field coincides with the polarization direction of the piezoelectric layer 42, this portion of the piezoelectric layer 42 contracts in the horizontal direction orthogonal to the polarization direction, and thereby the pressure chambers of the diaphragm 41 and the piezoelectric layer 42. As a whole, the portion facing 10 is deformed so as to be convex toward the pressure chamber 10 side. Due to this deformation, the volume of the pressure chamber 10 is reduced, the pressure of the ink in the pressure chamber 10 is increased, and an ink droplet is ejected from the nozzle 15 communicating with the pressure chamber 10 due to the pressure increase of the ink.

  Next, the FPC (Flexible Printed Circuit) 52 (second wiring board) connected to the COF 51 and the COF 51 will be described. FIG. 5 is an enlarged view of a portion in the vicinity of the driver IC 61 of the COF 51 and the FPC 52 of FIG. FIG. 6 is a view of FIG. 5 viewed from the direction of the arrow VI. In order to make the drawing easier to see, in FIG. 6, the output terminals 64 described later are not illustrated in the positions overlapping with the input terminals 63 described later.

  As shown in FIGS. 4 to 6, the COF 51 is disposed above the piezoelectric actuator 32, extends in the horizontal direction at a portion facing the piezoelectric actuator 32, and has one end portion that does not face the piezoelectric actuator 32. It is bent and extends upward. Further, the upper end portion of the portion extending above the COF 51 is connected to one end portion of the FPC 52. The other end of the FPC 52 is connected to a main body substrate control device (not shown).

  A driver IC 61 is mounted on the COF 51, and a plurality of output wirings 62 are formed. The driver IC 61 has a substantially rectangular planar shape, and is mounted on the right side surface in FIG. 4 of the COF 51 that extends upward so that the left-right direction in FIG. 6 is the longitudinal direction. . A plurality of input terminals 63 arranged at substantially equal intervals in the left-right direction in FIG. 6 are provided on the surface of the driver IC 61 opposite to the COF 51 (hereinafter referred to as the upper surface of the driver IC 61). Further, on the surface of the driver IC 61 on the COF 51 side (hereinafter referred to as the lower surface of the driver IC 61), the upper and lower ends in FIG. 6 are respectively arranged at substantially equal intervals in the left-right direction in FIG. A plurality of output terminals 64a and 64b are provided.

  Here, the plurality of input terminals 63 are for supplying power to the driver IC 61 and inputting signals from a main body substrate (not shown), and the plurality of output terminals 64a and 64b are connected to the piezoelectric actuator 32 from the driver IC 63. For outputting a drive signal for driving the.

  The plurality of output wirings 62 are provided corresponding to the plurality of nozzles 15, and are connected to the output terminals 64 a and 64 b of the driver IC 61. In the output wiring 62, the output wiring 62a connected to the output terminal 64a extends downward from the output terminal 64a in FIG. 6, and extends to the portion overlapping the corresponding land 44 in the extending direction of the COF 51 as it is. ing. On the other hand, the output wiring 62b connected to the output terminal 64b extends upward from the output terminal 64b in FIG. Along with the corresponding land 44, it extends to the portion that overlaps.

  Here, in the printer 1 of the present embodiment, for example, a large number of nozzles 15 are formed in the inkjet head 3 in order to realize high-resolution printing, but the piezoelectric actuator 32 side of the driver IC 61 (see FIG. 6 and the output wirings 62a and 62b from both sides opposite to the piezoelectric actuator 32 (upper side in FIG. 6), the output wirings 62 corresponding to the multiple nozzles 15 are formed on the COF 51. is doing.

  As described above, the driver IC 61 applies a driving potential to the individual electrode 43 via the output wiring 62 and the land 44, and holds the diaphragm 41 as a common electrode at the ground potential.

  A plurality of input wires 71 are formed in the FPC 52. Each of the plurality of input wirings 71 extends in the extending direction of the FPC 52 (vertical direction in FIG. 6) over the entire length of the FPC, and is arranged at substantially equal intervals in the horizontal direction in FIG. Further, connection terminals 72 are provided at the lower ends of the input wirings 71 in FIG.

  The connection terminals 72 of the plurality of input wirings 71 are respectively connected to the plurality of input terminals 63 of the driver IC 61 via a plurality of bonding wires 81 extending across the output wiring 62b on the COF 51. The plurality of bonding wires 81 are wires made of a conductive material such as gold, and both ends thereof are pressed against the input terminal 63 and the connection terminal 72, respectively, and the pressed portions are irradiated with ultrasonic waves. Thus, the input terminal 63 and the connection terminal 72 are joined. The plurality of bonding wires 81 all have the same length.

  Here, the driver IC 61 has a large restriction on the space for arranging the input terminals 63 for high integration. On the other hand, the FPC 52 has more space than the driver IC 61. The interval is wider than the interval between the input terminals 63. Therefore, the linear distance between the input terminal 63 and the connection terminal 72 is shorter toward the inner side in the left-right direction in FIG.

  Therefore, as shown in FIG. 5, the plurality of bonding wires 81 having the same length are different in loop height, and the input terminal 63 and the connection terminal on the inner side in the left-right direction in FIG. The height of the loop is higher in the bonding wire 81 that connects with the wire 72.

  The plurality of input wirings 71 include a power input wiring 71a connected to a power source provided on a main body substrate (not shown), a driving waveform signal input wiring 71b for inputting a driving waveform signal to the driver IC 61, and a nozzle to the driver IC 61. A plurality of data signal input wirings 71c for inputting ink ejection data signals from 15 and a clock input wiring 71d for inputting a clock are included. In this embodiment, the drive waveform signal input wiring 71b, the data signal input wiring 71c, and the clock input wiring 71d are signal input wirings according to the present invention.

  Here, the drive waveform signal is a signal having a drive waveform corresponding to the drive signal output from the output terminal 64, and a signal obtained by amplifying the drive waveform signal with the power supply voltage is output from the output terminal 64 as a drive signal. Is output.

  The ejection data signal is a signal indicating the timing of ejecting ink from the nozzles 15, and the drive signal is output from the output terminal 64 of the driver IC 61 at the timing indicated by the ejection data signal. At this time, for example, when there are a plurality of types of drive waveform signals, such as when a plurality of types of ink droplets can be ejected from the nozzle 15, the ejection data signal is output together with the ejection timing of the ink from the nozzle 15. It also shows which drive waveform signal is selected. The clock is a signal that serves as a reference for driving timing of the driver IC 61.

  In these wirings 71a to 71d, the drive waveform signal input wiring 71b is located inside the power supply input wiring 71a, and the data signal input wiring 71c and the clock input wiring 71d are located further inside than the drive waveform signal input wiring 71b. It is arranged to come to.

  As a result, the power input wiring 71a is connected to the bonding wire 81a having a low loop height, and the drive waveform signal input wiring 71b is connected to the bonding wire 81b having a higher loop height than the bonding wire 81a. 71c and the clock input wiring 71d are connected to a bonding wire 81c having a higher loop height than the bonding wire 81b.

  Then, when a drive signal is output from the driver IC 61 (output terminals 64a and 64b), as described above, a drive potential is applied to the individual electrode 43, the piezoelectric actuator 32 is driven, and an ink droplet is ejected from the nozzle 15. Be injected.

  Here, unlike the present embodiment, it is also conceivable that the input terminal 63 is provided on the lower surface of the driver IC 61 and the plurality of input wirings 71 and the input terminals 63 are connected via wirings formed on the COF 51. It is done.

  However, in this case, since the output wiring 62b is disposed in the COF 51 between the connection portion with the FPC 52 and the driver IC 61, the output wiring 62b, the input wiring 71, and the input terminal 63 are connected. Therefore, the wiring for this is arranged at a position close to each other. Therefore, noise may occur in a signal transmitted through the input wiring 71 and input to the driver IC 61 due to the influence of the drive signal transmitted through the output wiring 62b.

  At this time, since the voltage of the power source input to the driver IC 61 is approximately the same as the voltage of the drive signal transmitted through the output wiring 62 (for example, approximately 20 V), the influence of the noise is not so great. Since the waveform signal, the ejection data signal, the clock, and the like are signals having a voltage lower than the power supply voltage (for example, about 3.3 V), they are easily affected by the noise.

  Further, even if noise occurs in the drive waveform signal, there is a possibility that the drive signal output from the output terminal 64 may be slightly distorted corresponding to this, but this does not cause the drive signal itself to be output. The print quality is unlikely to deteriorate significantly.

  On the other hand, if noise occurs in the drive data signal indicating the ink ejection timing or the clock used as the reference for the drive timing of the driver IC 61, the ink droplets are ejected from the nozzle 15 at the timing when the ink droplets should be ejected. Piezoelectric actuators that are not ejected or, on the contrary, eject ink droplets at a timing other than the timing at which ink droplets should be ejected, or drive signals corresponding to drive waveform signals that are different from the drive waveform signals to be selected When such a problem occurs, the print quality may be greatly deteriorated.

  From the above, in this embodiment, signals such as drive waveform signals, ejection data signals, and clocks are more susceptible to noise than power supply voltages, and ejection data signals and clocks are particularly noise. It can be said that it is easy to be influenced by.

  In this case, the connection terminal 72 of the input wiring 71 on the FPC 52 and the connection terminal of the wiring connected to the input terminal 63 on the COF 51 are connected at the connection portion between the COF 51 and the FPC 52. Since the connection terminals on the different wiring boards are directly connected at the connection portions of these wiring boards, the impedance is greatly increased at the connection portions of these connection terminals, and this increase in impedance causes the driver IC 61 to increase the impedance. There is a possibility that the voltage of the input signal is greatly attenuated. In particular, since the drive waveform signal, the ejection data signal, the clock, and the like are low voltages, such voltage attenuation becomes a serious problem.

  On the other hand, in the present embodiment, the connection terminal 72 of the input wiring 71 on the FPC 52 and the input terminal 63 of the driver IC 61 are connected by the bonding wire 81 that is separated from the output wiring 62. The drive signal transmitted through 62 makes it difficult for noise to occur in the ejection data signal and clock transmitted through the input signal 71 and input to the driver IC 61. In addition, since there is no portion that causes an increase in impedance as described above between the input wiring 71 and the input terminal 63, a signal transmitted through the input wiring 71 is difficult to attenuate.

  Furthermore, since the lengths of the plurality of bonding wires 81 are all the same, the timing at which the above-described drive waveform signal, ejection data signal, clock, etc. are input to the driver IC 61 via the bonding wires 81 varies. As a result, it is possible to prevent variations in the ejection timing of ink from the plurality of nozzles 15.

  Further, since the lengths of the plurality of bonding wires 81 are all the same, all the bonding wires 81 can be formed using only one type of wire having the same length.

  However, even when the connection terminal 72 and the input terminal 63 are connected by the bonding wire 81, a signal transmitted through the bonding wire 81 is generated by a current flowing through the output wiring 62 when the drive signal is transmitted. There is a risk that noise may be generated due to the influence of the magnetic flux. At this time, the lower the loop height of the bonding wire 81, that is, the closer the bonding wire 81 is to the output wiring 62, the greater the influence of the magnetic flux and the more likely noise is generated.

  Therefore, in the present embodiment, as described above, the power supply input wiring 71a to which the power supply voltage that is not easily affected by noise is input is connected to the bonding wire 81a having a low loop height, so that the noise is lower than the power supply voltage. The drive waveform signal input wiring 71b to which the drive waveform signal that is easily affected by the transmission is transmitted is connected to the bonding wire 81b having a loop height higher than that of the bonding wire 81a. Furthermore, the data signal input wiring 71c and the clock input wiring 71d through which the ejection data signal and clock that are more susceptible to noise than the drive waveform signal are transmitted are connected to the bonding wire 81c having a loop height higher than that of the bonding wire 81b. Connected.

  As a result, it is possible to suppress as much as possible the occurrence of noise due to magnetic flux generated by the current flowing through the output wiring 62 in a signal that is susceptible to noise.

[Second Embodiment]
Next, a preferred second embodiment of the present invention will be described. However, components having the same configurations as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  FIG. 7 is a view corresponding to FIG. 5 in the second embodiment. FIG. 8 is a view corresponding to FIG. 6 in the second embodiment. As shown in FIGS. 7 and 8, in the second embodiment, the loop heights of the plurality of bonding wires 91 are all the same. However, in this case, as described above, since the interval between the input terminals 63 of the driver IC 61 is narrower than the interval between the connection terminals 72 of the FPC 52, the lengths of the plurality of bonding wires 91 are different from each other. The length of the one located inward in the left-right direction in FIG. 8 is shorter.

  Also in the second embodiment, as shown in FIG. 8, the drive waveform signal input wiring 71b among the power supply input wiring 71a, the drive waveform signal input wiring 71b, the data signal input wiring 71c, and the clock input wiring 71d described above is the same. The data signal input wiring 71c and the clock input wiring 71d are arranged further inside than the drive waveform signal input wiring 71b.

  As a result, the drive waveform signal input wiring 71b is connected to the bonding wire 91b that is shorter than the bonding wire 91a connected to the power input wiring 71a, and the data signal input wiring 71c and the clock input wiring 71d are connected to the bonding wire 91b. It is connected to the bonding wire 91c having a shorter length.

  Even in this case, since the connection terminal of the input wiring 71 on the FPC 52 and the input terminal 63 of the driver IC 61 are connected by the bonding wire 91 separated from the output wiring 62 as in the first embodiment, the output wiring 62 This makes it difficult for noise to be generated in the ejection data signal and clock input to the driver IC 61 by the drive signal transmitted, and causes an increase in impedance between the input wiring 71 and the input terminal 63 as described above. Since there is no portion, a signal transmitted through the input wiring 71 is difficult to attenuate.

  Further, as described above, even when the connection terminal 72 and the input terminal 63 are connected by the bonding wire 91, the output wire 62 is used when a signal transmitted through the bonding wire 81 is transmitted when an output signal is transmitted. There is a possibility that noise may be generated due to the influence of the magnetic flux generated by the current flowing in the wire. The lower the loop height of the bonding wire 91, the greater the influence of the magnetic flux, and the more likely noise is generated. If there is a variation in the loop height, there is a risk that the noise generated in the signal transmitted through the bonding wire 91 may vary.

  However, in the second embodiment, since the loop heights of the plurality of bonding wires 91 are the same, the noise generated in the signal or the like input from each bonding wire 91 to the driver IC 61 may vary. Can be prevented.

  In this way, if the loop heights of the bonding wires 91 are all the same, the variation in noise generated in the signals input from the bonding wires 91 to the driver IC 61 is reduced, but the length of the bonding wires 91 is reduced. Due to the difference, there is a slight variation in the noise generated in the transmitted signal. The longer the bonding wire 91 is, the greater the noise generated.

  Therefore, in the second embodiment, as described above, the input wiring 71 through which a signal susceptible to noise is transmitted is connected to the bonding wire 91 having a shorter length arranged on the inner side. It is possible to suppress as much as possible noise generated in a signal that is susceptible to the influence of.

  Next, modified examples in which various changes are made to the first and second embodiments will be described. However, the same components as those in the present embodiment are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  In the first and second embodiments, the input wiring 71 is formed on the FPC 52 different from the COF 51 on which the driver IC 61 is mounted. However, the input wiring 71 is on the same COF 51 on which the driver IC 61 is mounted. It may be formed.

  In the first embodiment, the case where the drive waveform signal, the ejection data signal, and the clock are input as input signals to the driver IC 61 has been described. However, signals other than these signals are input to the driver IC 61. The input wiring 71 for inputting a signal that is easily affected by noise may be connected to the bonding wire 81 having a higher loop height. Even in this case, it is preferable that all the input wirings 71 through which signals are transmitted are connected to bonding wires 81 having a loop height higher than that connected to the power input wiring 71a.

  Further, also in the second embodiment, signals other than the drive waveform signal, the ejection data signal, and the clock are input to the driver IC 61, and the input wiring 71 for inputting a signal that is easily affected by noise. It may be connected to the bonding wire 91 having a short length. Even in this case, it is preferable that all the input wirings 71 through which signals are transmitted are connected to the bonding wires 91 having a shorter length than those connected to the power input wiring 71a.

  In the first embodiment, all the bonding wires 81 have the same length. However, the present invention is not limited to this.

  For example, in the inkjet head 3, when the piezoelectric actuator 32 is driven, the deformation of the portion of the piezoelectric layer 42 facing the pressure chamber 10 is transmitted from the nozzle 15 to the portion facing the other pressure chamber 10. In order to prevent so-called crosstalk in which the ink ejection characteristics fluctuate, the first and third of the four nozzle rows 7 shown in FIG. 2 are counted from the left (from one side in one direction). Piezoelectric so as to change the ink ejection timing between the nozzles 15 constituting the (odd number) nozzle row 7a and the nozzles 15 constituting the second and fourth (even number) nozzle rows 7b counting from the left. The actuator 32 may be driven.

  In such a case, among the four nozzle rows 7 in FIG. 2, the data signal input wiring corresponding to the nozzles 15 constituting the first and third (odd number) nozzle rows 7a counting from the left. The lengths of the plurality of bonding wires 81c (first wires) connected to the connection terminals 72 of 71c (first injection data input wiring) are the same as each other, and the second and fourth (even numbers) from the left The lengths of the plurality of bonding wires 81c (second wires) connected to the connection terminals 72 of the data signal input wiring 71c (second ejection data input wiring) corresponding to the nozzles 15 constituting the (th) nozzle row 7b are mutually equal. As long as they are the same, the length of the first wire and the length of the second wire may be different from each other.

  Also in this case, the lengths of the plurality of bonding wires 81c (the first wires and the second wires) corresponding to the nozzles 15 ejecting ink droplets at the same timing are the same. It is possible to prevent variations in the timing at which the ejection data signal corresponding to the nozzles 15 ejecting droplets is input to the driver IC 61.

  In addition to the above example, when the input wiring 71 includes a plurality of signal input wirings for transmitting signals to be simultaneously input to the driver IC 61, the bonding wires 81 connected to these signal input wirings As long as the lengths are the same, the lengths of these bonding wires 81 and other bonding wires 81 may be different.

  In the above description, the example in which the present invention is applied to a printer that performs printing by ejecting ink droplets from the nozzles 15 has been described. However, the present invention is not limited to this, and a liquid device that ejects liquid other than ink or the like. The present invention can also be applied to a device driven by a driver IC.

3 Inkjet head 51 COF
52 FPC
61 Driver IC
62 output wiring 63 input terminal 64 output terminal 71 input wiring 71a power input wiring 71b drive waveform signal input wiring 71c data signal input wiring 71d clock input wiring 81 bonding wire

Claims (7)

A first wiring board;
A driver IC mounted on the first wiring board and having a plurality of input terminals for input and output terminals for output;
A plurality of output wirings formed on the first wiring board and connected to the output terminals of the driver IC;
A plurality of input wirings each having a connection terminal for connection with the input terminal of the driver IC;
A plurality of bonding wires that connect the input terminals of the driver IC and the connection terminals of the plurality of input wirings;
An interval between the input terminals is narrower than an interval between the connection terminals of the plurality of input wires,
The plurality of input wirings include a plurality of types of signal input wirings for transmitting a plurality of types of signals different from each other in sensitivity to noise,
Bonding wires connected to the plurality of types of signal input wirings have the same length as each other, and have different loop heights from the first wiring board,
A wiring connection structure of a driver IC, wherein a bonding wire connected to the connection terminal of a signal input wiring that transmits a signal susceptible to noise has a higher loop height.   2. The driver IC wiring connection structure according to claim 1, wherein the plurality of input wirings are formed on a second wiring board different from the first wiring board. The driver IC is for driving a droplet ejecting head that ejects droplets from a plurality of nozzles,
The plurality of types of signal input wirings are
Clock input wiring to input the clock,
An ejection data signal input wiring for inputting a signal of ejection data indicating ejection timing of droplets from the plurality of nozzles;
A drive waveform signal input wiring for inputting a drive waveform signal corresponding to a drive signal for driving the droplet ejection head, which is output from the output terminal of the driver IC,
The loop height of the bonding wire connected to the connection terminal of the drive waveform signal input wiring is equal to the loop height of the bonding wire connected to the connection terminal of the clock input wiring and the ejection data signal input wiring. The wiring connection structure of the driver IC according to claim 1, wherein the wiring connection structure is higher than the height. The plurality of input wirings further includes a power input wiring connected to a power source;
The bonding wire connected to the connection terminal of the power input wiring has the same length as the bonding wire connected to the connection terminal of the plurality of types of signal input wirings, and the bonding wire is more than the bonding wire. 4. The wiring connection structure for a driver IC according to claim 1, wherein the loop height is low. A droplet ejection head that ejects droplets from a plurality of nozzles;
A first wiring board connected to the liquid droplet ejecting head;
A driver IC mounted on the first wiring board, each having a plurality of input terminals for input and output terminals for output, and driving the droplet ejection head;
A plurality of output wirings formed on the first wiring board and connected to the output terminals of the driver IC;
A plurality of input wirings each having a connection terminal for connection with the input terminal;
A plurality of bonding wires that connect the input terminals of the driver IC and the connection terminals of the plurality of input wirings;
The plurality of nozzles form a plurality of nozzle rows arranged along one direction,
An interval between the input terminals of the driver IC is narrower than an interval between the connection terminals of the plurality of input wires.
The plurality of input wirings are:
A plurality of first ejection data signal input wirings for inputting ejection data signals indicating ejection timings of droplets from a plurality of nozzles constituting an odd-numbered nozzle row counted from one side in the one direction;
A plurality of second ejection data signal input wirings for inputting ejection data signals indicating ejection timings of droplets from a plurality of nozzles constituting even-numbered nozzle rows counted from one side in the one direction. And
The plurality of bonding wires are connected to the plurality of first wires connected to the connection terminals of the plurality of first ejection data signal input lines and the connection terminals of the plurality of second ejection data signal input lines. A plurality of second wires;
The plurality of first wires have the same length as each other;
The droplet ejecting apparatus, wherein the plurality of second wires have the same length. A first wiring board;
A driver IC mounted on the first wiring board and having a plurality of input terminals for input and output terminals for output;
A plurality of output wirings formed on the first wiring board and connected to the output terminals of the driver IC;
A plurality of input wirings each having a connection terminal for connection with the input terminal;
A plurality of bonding wires that connect the input terminals of the driver IC and the connection terminals of the plurality of input wirings;
The interval between the input terminals is narrower than the interval between the plurality of input wiring terminals,
The connection structure of the driver IC, wherein the plurality of bonding wires have the same loop height from the first wiring board.   7. The driver IC wiring connection structure according to claim 6, wherein the plurality of input wirings are formed on a second wiring board different from the first wiring board.

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