JP4968253B2 - Droplet discharge head and droplet discharge apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the droplet discharge head including a piezoelectric actuator having a structure which prevents deformation at the piezoelectric deformation parts of adjoining discharge energy imparting parts from interfering with each other even if the energy imparting parts are arranged densely, and to provide a wiring structure suitable for such a droplet discharge head. <P>SOLUTION: On the flexible wiring board 30 of the droplet discharge head 1, the second electric potential feeding line 74 and the second power supply wiring 33 which impart a potential to a drive IC 50 have a common wiring part at least partially, the first electric potential feeding line 28 and the first power supply wiring 31 are arranged on the opposite sides of the common wiring part with a space from each other, and a connection line is provided to connect the first electric potential feeding line 28 and the first power supply wiring 31 while jumping over the common wiring part. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a droplet discharge head and a droplet discharge apparatus including the same.

  A general ink jet recording apparatus includes a carriage that reciprocates and a droplet discharge head mounted on the carriage. The droplet discharge head applies discharge energy to the liquid in the individual liquid channel and the channel unit in which a plurality of nozzles for discharging droplets, a plurality of individual liquid channels from the common liquid chamber to the nozzles are formed, and A discharge energy application unit, a drive IC that generates a drive signal, and a wiring unit provided with a signal circuit and a power supply wiring that supply the drive signal to the discharge energy application unit. As such a discharge energy applying unit, for example, a piezoelectric actuator is known that applies pressure as discharge energy to the liquid in the pressure chamber by changing the volume of the pressure chamber provided in the individual liquid flow path.

  For example, as shown in Patent Document 1, a piezoelectric actuator is sandwiched between individual electrodes provided at positions facing each pressure chamber, a common electrode straddling a plurality of pressure chambers, and a plurality of individual electrodes and a common electrode. Provided with a piezoelectric sheet. The portion of the piezoelectric sheet sandwiched between the individual electrode and the common electrode is activated by being polarized, and the activated piezoelectric sheet and the individual electrode and the common electrode sandwiching the piezoelectric sheet are liquidated in the pressure chamber. It is a discharge energy applying unit that applies a droplet discharge pressure. The piezoelectric actuator configured as described above is joined to the flow path unit so that each discharge energy applying unit and each pressure chamber correspond to each other.

  In addition, the wiring unit includes a flexible wiring board provided with a driving IC for generating a driving signal, a signal wiring for applying a driving signal to the individual electrodes of the piezoelectric actuator, a power supply wiring for applying a potential to the common electrode, and the like. It has. This flexible wiring board is fixed to the upper surface of the piezoelectric actuator.

Regarding the polarization of the piezoelectric actuator performed at the time of manufacturing the droplet discharge head as described above, Patent Document 1 discloses that a positive potential (30 V) is applied from the drive IC to the individual electrode, and a negative power source is applied to the common electrode. A method is described in which a high voltage (70 V) is applied to a piezoelectric deformation portion sandwiched between these electrodes by applying a potential (−40 V) to polarize the piezoelectric deformation portion. According to this polarization method, the load applied to the drive IC is reduced, and the drive IC can be protected.
JP 2002-160372 A

  There is a demand for high resolution and high speed printing of ink jet recording apparatuses. High resolution and high speed printing can be realized by increasing the number of nozzles provided in the flow path unit of the droplet discharge head. However, if the number of nozzles is increased while maintaining the size of the droplet discharge head, the nozzles are arranged at a high density in the flow path unit, so that the discharge energy applying portions corresponding to each nozzle are also arranged at a high density in the piezoelectric actuator. Will be. As described above, in the droplet discharge head including the piezoelectric actuator in which the discharge energy applying portions are densely arranged, the deformation of the piezoelectric deformation portion (piezoelectric sheet) of the adjacent discharge energy applying portion is prevented from interfering with each other. A structure is needed.

  Therefore, in the present invention, even when the discharge energy applying portions are arranged densely, the liquid including the piezoelectric actuator having a structure for preventing the deformation of the piezoelectric deformation portions of the adjacent discharge energy applying portions from interfering with each other. An object is to provide a droplet discharge head. In addition, a wiring structure suitable for such a droplet discharge head is proposed.

  The droplet discharge head of the present invention includes a flow path unit having a plurality of individual liquid flow paths extending from a common liquid chamber to a nozzle via a pressure chamber, and each of the individual liquid flow paths stacked and fixed to the flow path unit. A wiring board provided with a piezoelectric actuator that individually applies a liquid discharge pressure to the piezoelectric actuator, and a driving IC that is bonded to the piezoelectric actuator and applies a driving signal that takes at least a first potential and a second potential to the piezoelectric actuator The piezoelectric actuator includes a plurality of individual electrodes provided corresponding to the plurality of pressure chambers, and a plurality of the plurality of individual electrodes provided corresponding to the plurality of individual electrodes. A plurality of upper constant potential electrodes that are slightly smaller than the individual electrodes stacked on the flow path unit side of the individual electrodes via a first piezoelectric layer, and provided corresponding to the plurality of individual electrodes. A plurality of lower constant potential electrodes stacked on the upper constant potential electrode via a second piezoelectric layer, a first connection electrode connected to all of the plurality of lower constant potential electrodes, and the plurality of upper constant potentials A second connection electrode connected to all of the electrodes, the wiring board corresponding to the plurality of individual electrode connection lands provided corresponding to the plurality of individual electrodes, and corresponding to the first connection electrode A first connection land provided; a second connection land provided corresponding to the second connection electrode; a recording signal input line for inputting a recording signal to the driving IC; and a recording signal from the driving IC. A plurality of drive signal output lines for outputting the drive signals generated corresponding to the plurality of individual connection terminals, a first potential supply line for supplying a first potential and a second potential to the drive IC, and To the second potential supply line and the first connection land A first power supply wiring that is applied to apply a first potential to the plurality of lower constant potential electrodes, and a second potential applied to the plurality of upper constant potential electrodes connected to the second connection land. A second power supply line, and the second potential supply line and the second power supply line at least partially have a common wiring part on the wiring board, the first potential supply line and the first power supply line. The power supply wiring is arranged so as to be separated from each other with the common wiring portion interposed therebetween, and a connection line for connecting the first potential supply line and the first power supply wiring is provided.

  In the droplet discharge head having the above configuration, even if the piezoelectric deformation portions are densely arranged in the piezoelectric actuator, the piezoelectric deformation portions are deformed so as to cancel the deformation between the adjacent piezoelectric deformation portions. The deformations do not interfere with each other. Further, since the second potential supply line and the second power supply wiring have a common wiring portion at least in part, the number of terminals and connectors connected to these wirings can be reduced, which can contribute to cost reduction. Furthermore, since the wiring area on the wiring board can be reduced, the size of the wiring board can be reduced, which can contribute to cost reduction and downsizing.

  The first power supply wiring is disposed along an edge of the wiring board, and the common wiring portion of the second power supply wiring and the second potential supply line is disposed in parallel to the first power supply wiring. It is good to have.

  Further, it is preferable that the first potential supply line is disposed in parallel with the second potential supply line.

Further, in the piezoelectric actuator, the plurality of individual electrodes are arranged at a substantially central portion of a surface to be bonded to the wiring board, and the first connection electrode is opposed to the first direction of the surface to be bonded to the wiring board. are arranged along the two sides of the edge of the second connection electrode of the first connection electrode is the at the edge of two sides facing extending in the first direction provided first connection electrode said first direction In the wiring board, the first connection land and the second connection land correspond to the first connection electrode and the second connection electrode in a connection range where the piezoelectric actuators are stacked. As described above, it is desirable that the first connection lands are arranged in the first direction, and the first connection land is arranged inside the first power supply wiring.

  The droplet discharge device of the present invention includes a droplet discharge head, a liquid supply source that supplies a colored liquid to the droplet discharge head, a carriage that holds the droplet discharge head, and a reciprocating scan of the carriage. And a main body frame that supports the body.

  The present invention has the following effects.

  According to the present invention, in the piezoelectric actuator provided in the droplet discharge head, even when the piezoelectric deformation portions are densely arranged, the deformation of the adjacent piezoelectric deformation portions can be made non-interfering. In addition, the second potential supply line for applying a driving potential to the driving IC and the second power supply wiring for applying a potential to the upper constant potential electrode at least partially have a common wiring portion, thereby reducing the cost of the droplet discharge head. And it can contribute to size reduction.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference symbols throughout the drawings, and redundant description thereof is omitted. In the following description, the side from which droplets are ejected is referred to as a lower surface and a downward direction, and the opposite side is referred to as an upper surface and an upward direction.

[Embodiment 1]
First, an outline of the configuration of an inkjet recording apparatus 100 that is a droplet discharge apparatus including the droplet discharge head according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a plan view of an ink jet recording apparatus provided with a droplet discharge head according to an embodiment of the present invention.

  The ink jet recording apparatus 100 can be applied not only as a single printer apparatus but also as a printer function of a multi-function device (MFD) having a copy function, a scanner function, a facsimile function, and the like. It is. As shown in FIG. 1, an ink jet recording apparatus 100 is mounted inside a main body frame 2, and a carriage 3 that reciprocates along a main scanning direction (hereinafter referred to as “Y direction”), and the carriage 3. A droplet discharge head 1 is provided.

  The carriage 3 is slidably supported by a rear guide shaft 6 and a front guide shaft 7 that are provided in parallel in the Y direction in the main body frame 2, and is a timing that is an endless belt with the carriage drive motor 17. The belt 18 is configured to reciprocate in the Y direction. In the carriage 3, four color liquids (for example, black, yellow, magenta, and cyan ink) provided in the main body frame 2 are supplied from liquid supply sources 5 a to 5 d through liquid supply pipes 14 a to 14 d. The supplied colored liquid is stored, and from here, the colored liquid is independently supplied to the droplet discharge head 1 for each color.

  Then, the recording paper Pa, which is a recording medium, is placed on the lower surface side of the droplet discharge head 1 along a direction perpendicular to the Y direction (hereinafter referred to as “X direction”) by a known recording paper transport mechanism (not shown). The droplets of colored liquid (ink) are ejected downward from the nozzles of the droplet ejection head 1 moving in the Y direction on the recording paper Pa and printed on the recording paper Pa. .

[Droplet discharge head 1]
Next, the configuration of the droplet discharge head 1 will be described with reference to FIGS. 2 is an exploded perspective view showing the configuration of the droplet discharge head according to Embodiment 1, FIG. 3 is a partial cross-sectional view of the head body in the X direction, and FIG. 4 is a partial cross-sectional view of the head body in the Y direction. 5 is a plan view of the piezoelectric actuator according to the first embodiment, FIG. 6 is a bottom view of the wiring unit according to the first embodiment, and FIG. 7 is a cross-sectional view of the wiring unit.

  As shown in FIGS. 2 to 4, the droplet discharge head 1 includes a flow path unit 11 in which a plurality of individual liquid flow paths are formed from a manifold 81 that is a common liquid chamber to a nozzle 85 via a pressure chamber 83. A piezoelectric actuator 12 having a plurality of ejection energy applying portions 40 provided corresponding to each of the individual liquid channels so as to selectively eject droplets from a predetermined nozzle 85 among the plurality of nozzles 85, and A signal circuit for supplying a drive signal to the ejection energy application unit 40 of the piezoelectric actuator 12 and a wiring unit 13 provided with power supply wiring are sequentially stacked from below. In this droplet discharge head 1, a head main body 15 is composed of a flow path unit 11 and a piezoelectric actuator 12 which are stacked and fixed.

[Flow path unit 11]
First, the flow path unit 11 will be described. The flow path unit 11 is a laminated body of a plurality of plate members, and a plurality of nozzles 85 are opened on the lower surface thereof. The plurality of nozzles 85 form one or more rows extending in the X direction. The plurality of nozzles 85 arranged in one nozzle row are arranged at a predetermined interval from each other and eject droplets of the same color. The nozzle rows are arranged at appropriate intervals in the Y direction, and six rows are provided for each color of liquid ejected from the nozzle 85.

  Inside the flow path unit 11 are formed a manifold 81 that is a common liquid chamber for storing colored liquids by color, and individual liquid flow paths that connect the manifold 81 and the nozzles 85. The individual liquid flow path is provided corresponding to each nozzle 85 and includes a pressure chamber 83 that temporarily stores liquid, a throttle portion 82 that communicates the manifold 81 and the pressure chamber 83, and the nozzle 85 and the pressure chamber 83. Each space includes a descender hole 84 and the like that communicate with each other.

  On the upper surface of the flow path unit 11, liquid supply ports 14 connected to the liquid supply sources 5a to 5d (FIG. 1) are provided for each liquid color. The colored liquid supplied from the liquid tank to each liquid supply port 19 flows into the manifold 81 in the flow path unit 11 and reaches the pressure chamber 83 via the throttle portion 82. The liquid in the pressure chamber 83 is discharged from the nozzle 85 through the descender hole 84 when the pressure chamber 83 receives the discharge pressure.

[Piezoelectric actuator 12]
Next, the piezoelectric actuator 12 will be described. As shown in FIGS. 2 to 5, the piezoelectric actuator 12 includes two upper and lower piezoelectric layers 23, an upper piezoelectric layer 21 and a lower piezoelectric layer 22, stacked on a bottom layer 24 serving as a substrate. The piezoelectric layer 23 is formed of a piezoelectric sheet made of a piezoelectric material such as PZT. Hereinafter, the stacking direction of the piezoelectric layers 23 is referred to as “Z direction”.

  On the upper side of the upper piezoelectric layer 21, a plurality of individual electrodes 42 corresponding to the respective pressure chambers 83 are provided. Between the upper piezoelectric layer 21 and the lower piezoelectric layer 22, a plurality of upper constant potential electrodes 46 corresponding to each individual electrode 42 (pressure chamber 83) are provided. A plurality of lower constant potential electrodes 47 straddling a plurality of pressure chambers 83 arranged in the X direction are formed between the lower piezoelectric layer 22 and the bottom layer 24. The portion of the piezoelectric layer 23 sandwiched between the individual electrode 42 and the lower constant potential electrode 47 is a piezoelectric deformation portion of the discharge energy applying portion 40, and the piezoelectric deformation portion of the discharge energy applying portion 40 is deformed. Thus, the discharge pressure can be applied to the liquid in the pressure chamber 83.

  The plurality of individual electrodes 42 are juxtaposed on the upper piezoelectric layer 21 at substantially constant intervals on the upper piezoelectric layer 21 so as to face the pressure chamber 83, and the rows of the individual electrodes 42 are shifted in a staggered manner in the Y direction. Has been. A part of the individual electrode 42 projects in the Y direction, and this projecting portion serves as a connection terminal 41 connected to the individual electrode connection land 60 provided in the wiring unit 13.

  The plurality of upper constant potential electrodes 46 are provided on the lower piezoelectric layer 22 at positions corresponding to the individual electrodes 42 in the Z direction. All the upper constant potential electrodes 46 included in the piezoelectric actuator 12 are electrically connected, and a common potential is applied to all the upper constant potential electrodes 46.

  The lower constant potential electrode 47 is formed in a strip shape extending over a plurality of pressure chambers 83 arranged in the X direction, and the plurality of strip electrodes are arranged in the Y direction. All the lower constant potential electrodes 47 provided in the piezoelectric actuator 12 are electrically connected, and a common potential is applied to all the lower constant potential electrodes 47.

  In these electrodes 42, 46 and 47, the length of the upper constant potential electrode 46 in the X direction is shorter than the length of the individual electrode 42 in the X direction. Therefore, the individual electrode 42, the upper constant potential electrode 46, and the lower constant potential electrode 47 overlap in the Z direction at a substantially central portion in the X direction of the individual electrode 42. In this way, the portion of the upper piezoelectric layer 21 sandwiched between the individual electrode 42 and the upper constant potential electrode 46 where the three layers of electrodes 42, 46, 47 overlap in the Z direction in the piezoelectric actuator 12 is hereinafter referred to as “ It is referred to as “first active part 36”. The portion of the upper piezoelectric layer 21 sandwiched between the upper constant potential electrode 46 and the lower constant potential electrode 47 where the three layers of electrodes 42, 46, 47 overlap in the Z direction is hereinafter referred to as “third active potential”. Part 38 ".

  On the other hand, at both ends of the individual electrode 42 in the X direction, the individual electrode 42 and the lower constant potential electrode 47 overlap in the Z direction, and the upper constant potential electrode 46 does not exist between these electrodes. The portion of the piezoelectric layer 23 sandwiched between the individual electrode 42 and the lower constant potential electrode 47 overlapping in the Z direction in the piezoelectric actuator 12 is hereinafter referred to as “second active portions 37, 37”. These active portions 36, 37, and 38 have a function as a capacitor. Among these active portions 36, 37, and 38, the first active portion 36 and the second active portion 37 have a voltage applied during droplet discharge. It is polarized and activated in the same direction as the direction.

  A first connection electrode 43 and a second connection electrode 44 are formed on the upper surface of the piezoelectric actuator 12 along both end edges in the Y direction. The second connection electrodes 44 are respectively arranged at the four corners of the upper surface of the piezoelectric actuator 12, and the first connection electrode 43 is arranged so as to be sandwiched between two second connection electrodes 44, 44 arranged in the X direction. The first connection electrode 43 is electrically connected to the lower constant potential electrode 47 through a conductive material filled in a through hole penetrating the upper piezoelectric layer 21 and the lower piezoelectric layer 22 in the Z direction. The second connection electrode 44 is electrically connected to the upper constant potential electrode 46 through a conductive material filled in a through hole penetrating the upper piezoelectric layer 21 in the Z direction.

[Wiring unit 13]
Next, the wiring unit 13 will be described. As shown in FIGS. 2, 6, and 7, the wiring unit 13 includes a flexible wiring board 30 made of a flexible synthetic resin material having electrical insulation, and two drives mounted on the flexible wiring board 30. ICs 50 and 50 are provided. The flexible wiring board 30 has a number of wires corresponding to the number of COFs (chip-on-film) 30a as the first flexible wiring board on which the drive ICs 50 and 50 are mounted and the number of recording signal input lines 71 of the COF 30a. FFC (flexible flat cable) 30b, 30b as a second flexible wiring board on which a simple wiring pattern is formed. These first and second flexible wiring boards are both printed boards on which wiring is printed.

  The flexible wiring board 30 uses a flexible synthetic resin material (for example, polyimide resin) having electrical insulation as a base material 58. A copper foil layer 57 is formed on one surface of the base material 58. The copper foil layer 57 has a plurality of individual electrode connection lands 60, a plurality of constant potential electrode connection lands 32, 34, and a plurality of wiring patterns 71, 72, 31, 33 are formed of a photoresist or the like. And the surface of the copper foil layer 57 is coat | covered with the cover layer 56 which consists of flexible synthetic resin (for example, polyimide resin) which has electrical insulation. A hole is formed in a portion of the base material 58 that overlaps with the individual electrode connection land 60 and the constant potential electrode connection land 32, 34, and the individual electrode connection land 60 and the constant potential electrode connection land 32, 34 exposed in the hole. Solder bumps 63 are fixed to each other.

  The piezoelectric actuator 12 is joined to the portion of the flexible wiring board 30 that is surrounded by the two-dot chain line 29 in FIG. The individual electrode connection land 60 is provided at a position corresponding to the connection terminal 41 provided on the surface of the piezoelectric actuator 12 in the Z direction, and the individual electrode connection land 60 is electrically connected to the connection terminal 41 via the solder bump 63. Has been. Further, the individual electrode connection land 60 is connected to the output side of the drive ICs 50, 50 by a drive signal output line 72. With this configuration, the drive signals generated by the drive ICs 50 and 50 are applied to the connection terminals 41 of the ejection energy application units 40 via the drive signal output lines 72 and the individual electrode connection lands 60.

  Of the constant potential electrode connection lands 32 and 34, the second connection land 34 is provided at a position corresponding to the second connection electrode 44 of the piezoelectric actuator 12 in the Z direction, and the first connection land 32 is the first connection land 32 of the piezoelectric actuator 12. The connection electrode 43 is provided at a position corresponding to the Z direction. The second connection land 34 is electrically connected to the second connection electrode 44 via the solder bump 63, and the first connection land 32 is electrically connected to the first connection electrode 43 via the solder bump 63. Further, the constant potential electrode connection lands 32 and 34 are connected to a power source via a first power supply line 31 or a second power supply line 33 provided on the flexible wiring board 30. With this configuration, a power supply voltage is applied to the upper constant potential electrode 46 and the lower constant potential electrode 47 via the power supply wires 31 and 33 and the constant potential electrode connection lands 32 and 34.

  Drive ICs 50 and 50 are provided on both sides in the X direction of the group of connection lands 60, 32 and 34 provided on the flexible wiring board 30. A recording signal input line 71 for inputting print data and a driving signal output line 72 for outputting a driving signal are connected to the driving IC 50. Then, the driving IC 50 that has received the recording signal from the recording signal input line 71 generates a driving signal that can take at least the first potential and the second potential in correspondence with the recording signal, and outputs a piezoelectric signal through the driving signal output line 72. A drive signal is applied to the discharge energy applying unit 40 of the actuator 12.

The first power supply wiring 31 extends in the X direction along both ends of the flexible wiring board 30 in the Y direction. The first power supply wiring 31 protrudes inward at a substantially central portion in the X direction of the range 29 to be joined to the piezoelectric actuator 12 of the flexible wiring board 30, and a plurality of first connection lands 32 are provided in the protruding portion. . That is, the first connection land 32 is arranged on the inner side than the first power supply wiring 31. The first power supply wiring 31 is a _VSS3 wiring that _applies a first potential to the lower constant potential electrode 47 of the piezoelectric actuator 12.

In the flexible wiring board 30, four second power supply wires 33, 33, which extend in the X direction, are wired inside the first power supply wires 31, 31. The second power supply wiring 33 is a V _DD3 wiring that _applies a second potential to the upper constant potential electrode 46 of the piezoelectric actuator 12.

Two second power supply wirings 33 are provided along both ends of the flexible wiring board 30 in the Y direction. The two second power supply wires 33 arranged in the Y direction are connected by a second potential supply line 74 connected to the high potential side input portion of the drive ICs 50, 50. The second potential supply line 74 is a V _DD2 wiring that applies a second potential that is higher than the first potential to the drive ICs 50 and 50.

  On the flexible wiring board 30, the second power supply wiring 33 that applies the second potential to the ejection energy applying unit 40 of the piezoelectric actuator 12 and the second potential supply line 74 that applies the second potential to the driving IC 50 are At least a portion has a common wiring portion. This common wiring portion is a wiring portion from the second power supply wiring 33 until the second potential supply line 74 branches. Thus, when the second power supply wiring 33 and the second potential supply line 74 have a common wiring portion, the number of terminals and connectors connected to these wirings is reduced, which contributes to cost reduction. Can do. Furthermore, since the power supply wiring area in the flexible wiring board 30 can be reduced, the size of the flexible wiring board 30 can be reduced, which can contribute to cost reduction and downsizing.

Furthermore, the low potential side of the drive ICs 50 and 50 along the substantially U-shaped inner side formed by the two second power supply wires 33 and 33 arranged in the Y direction and the second potential supply line 74 connected thereto. A first potential supply line 28 connected to the input unit is wired. A plurality of recording signal input lines 71 having one end connected to the drive IC 50 are arranged further inside the first potential supply line 28. The first potential supply line 28 is _{V SS2} wiring for imparting a first potential (ground potential) to the drive IC50,50. The first potential supply line 28 and the first power supply line 31 are electrically connected by a connection line 70 made of, for example, a jumper line across the common wiring portion of the second power supply line 33 and the first potential supply line 28 and shared. Potential (for example, 0V when grounded).

[Driving Circuit for Inkjet Recording Apparatus 100]
Here, an electrical circuit of the entire inkjet recording apparatus 100 will be described. FIG. 8 is a drive circuit diagram of the ink jet recording apparatus.

  As shown in FIG. 8, the main body side substrate 90 and the head substrate 91 provided on the main body side of the ink jet recording apparatus 100, and the drive IC 50 and the piezoelectric actuator 12 provided on the droplet discharge head 1 are connected to each other. Yes. A control circuit 93, a control signal power supply 94, and a discharge power supply 95 are mounted on the main body side substrate 90. The main body side substrate 90 is installed at a stationary position outside the carriage 3 on which the droplet discharge head 1 is mounted, and the head substrate 91 is mounted on the carriage 3 together with the drive IC 50 and the piezoelectric actuator 12.

  The drive IC 50 includes a data output unit 96 and a driver unit 97. The data output unit 96 of the drive IC 50 includes shift registers 106, D flip-flops 107, and AND gates 108 corresponding to the number of ejection energy applying units 40 (number of nozzles 85 and pressure chambers 83). Further, the driver unit 97 discharges a driver circuit 110 for converting the drive data output from the data output unit 96 into a voltage for driving the discharge energy applying unit 40 of the piezoelectric actuator 12 and outputting the voltage to the individual electrode 42. Corresponding to the number of energy applying units 40.

The control circuit 93 of the main body side substrate 90 outputs control signals such as enable, print data, clock, and strobe signal to the data output unit 96 of the driving IC 50 based on predetermined recording information, and outputs the control signals. Are connected to the data output section 96 via the control signal wiring 98. The control signal power supply 94 of the main body side substrate 90 supplies a voltage (for example, 5 volts) to the data output unit 96, and is supplied to the data output unit 96 through the drive wiring V _DD1 and the ground wiring V _SS1. It is connected. Further, the discharge power source 95 of the main body side substrate 90 supplies a voltage (for example, 30 volts) to the driver unit 97, and includes a driving V _DD2 wiring for applying a driving voltage and a grounding _VSS2 wiring. Via the driver unit 97. Further, an electrolytic capacitor 109 is bypass-connected on the head substrate 91 to the V _DD2 wiring and the _VSS2 wiring, and the electrolytic capacitor 109 stores the charge supplied to the driver unit 97, and the driver unit 97 has a large instantaneous moment. Occurrence of voltage drop when current flows is suppressed.

Each discharge energy applying unit 40 included in the piezoelectric actuator 12 is provided with three active units 36, 37, and 38 that function as capacitors. The lower constant electric potential electrode 47 are connected _{V SS3} wiring, the _{V SS3} wires are connected by a connecting line 70 on _{V SS2} wiring and the flexible wiring board 30 connected to the discharge power supply 95. With this configuration, a lower potential (first potential) is applied from the discharge power supply 95 to the lower constant potential electrode 47 through the V _SS2 wiring and the V _SS3 wiring.

On the other hand, the V _DD3 wiring is connected to the upper constant potential electrode 46, and this V _DD3 wiring is connected to the driving V _DD2 wiring connected to the ejection power supply 95 on the flexible wiring board 30. With this configuration, a higher potential (second potential) is applied to the upper constant potential electrode 46 from the discharge power supply 95 through the V _DD2 wiring and the V _DD3 wiring.

[Operation of the droplet discharge head 1]
Next, the operation of the droplet discharge head 1 having the above configuration will be described. FIG. 9 is a timing chart of driving of the discharge energy applying unit.

As shown in FIG. 9, regardless of when the droplet discharge head 1 is on standby or when it is driven, a second potential (for example, 30 V) is always applied to the upper constant potential electrode 46 through the V _DD2 wiring and the V _DD3 wiring. A first potential (for example, 0 V) is always applied to the lower constant potential electrode 47 through the V _SS2 wiring and the V _SS3 wiring.

  As is well known, when the reset signal of the shift register 106 and the D flip-flop 107 of the data output unit 96 of the driving IC 50 is in the L state, the print data (0 when ejection is present, no ejection) from the image memory of the control circuit 93, as is well known. 1) is read out serially and input to the shift register 106. In the shift register 106, the print data is converted into parallel data corresponding to the number of nozzles 85 of one droplet discharge head 1. Further, the print data converted into parallel data is latched by the D flip-flop 107 and output to the AND gate 108 in synchronization with the strobe signal.

In the standby drive IC 50, an L enable signal is given to each AND gate 108 of the data output unit 96, and the drive IC 50 turns off each driver circuit 110 of the driver unit 97 and passes through the _{VSS 2} wiring. A first potential is applied to the individual electrode 42.

  Therefore, in the ejection energy application unit 40 during standby, the first potential is applied to the individual electrode 42 and the lower constant potential electrode 47, and the second potential is applied to the upper constant potential electrode 46. As a result, the upper piezoelectric layer 21 of the first active portion 36 to which a voltage is applied in the same direction as the polarization direction expands in the Z direction toward the pressure chamber 83 and contracts in the X direction (see FIG. 3). At this time, since the lower piezoelectric layer 22 is bonded to the bottom layer 24, a difference in distortion in the X direction occurs between the upper piezoelectric layer 21 and the lower piezoelectric layer 22. In this way, the piezoelectric layer 23 and the bottom layer 24 project and deform in the Z direction toward the pressure chamber 83, and the volume of the pressure chamber 83 decreases.

On the other hand, in the driving IC 50 at the time of driving, the H enable signal is given to the AND gate 108 for a predetermined time. At this time, if the data latched in the D flip-flop 107 is “1” indicating no ejection, the driving IC 50 continues to turn off the driver circuit 110 corresponding to the data. On the other hand, if the data latched in the D flip-flop 107 is 0 with ejection, the driving IC 50 turns on the driver circuit 110 corresponding to the data, and _applies the second potential to the individual electrode 42 through the V _DD2 wiring. Then, after a predetermined time elapses, an L enable signal is applied to the AND gate 108, and the drive IC 50 turns off each driver circuit 110 and _applies the first potential to the individual electrode 42 via the _VSS2 wiring.

  As described above, the second potential is applied to the individual electrode 42 and the upper constant potential electrode 46 of the driven ejection energy applying unit 40, and the first potential is applied to the lower constant potential electrode 47. At this time, the upper piezoelectric layer 21 of the first active part 36 to which no voltage is applied in parallel to the polarization direction recovers from deformation, and the second active parts 37 and 37 to which voltage is applied in parallel to the polarization direction It tries to expand in the Z direction toward 83 and contract in the X direction. As a result, the piezoelectric layer 23 of the second active portion 37, 37 is deformed so as to warp away from the pressure chamber 83, the volume of the pressure chamber 83 increases, and the liquid is sucked into the pressure chamber 83 from the manifold 81. .

  Then, after a predetermined time has elapsed since the ejection energy applying unit 40 was driven, the same potential as that during standby is applied to the electrodes 42, 46 and 47. At this time, as in the standby state, a voltage is applied to the first active portion 36 in parallel with the polarization direction, and the piezoelectric layer 23 and the bottom layer 24 project and deform in the Z direction toward the pressure chamber 83, and the pressure chamber 83. The volume of is reduced at once. Thereby, the liquid is discharged from the nozzle 85.

  In the droplet discharge head 1 operating as described above, the second active portion 37 is displaced so as to suppress the displacement of the first active portion 36. Therefore, even if the discharge energy applying portion of the piezoelectric actuator is increased in density, Mutual non-interference of the deformation of the piezoelectric deformation portion of the ejection energy applying portion is realized.

[Polarization method]
Next, a polarization method of the piezoelectric actuator 12 included in the droplet discharge head 1 will be described. FIG. 10 is a circuit diagram of a droplet discharge head during polarization, FIG. 11 is a cross-sectional view of a piezoelectric actuator at a first stage of polarization, and FIG. 12 is a cross-sectional view of a piezoelectric actuator at a second stage of polarization.

  In the manufacturing process of the droplet discharge head 1, the piezoelectric actuator 12 is superposed on the flow path unit 11, and the connection terminals 41 and the surface constant potential electrodes 44, 43 of the piezoelectric actuator 12 are connected to the connection lands 60, 32, After being joined to 34 with solder, the piezoelectric layer 23 of the piezoelectric actuator 12 is polarized. Here, this polarization process will be described.

  As shown in FIG. 10, the polarization device includes a polarization circuit 113 that generates a part of the polarization voltage, a power supply 112 that generates the remaining part of the polarization voltage, and signals such as an enable signal and a reset signal. A signal generation circuit 111 for generating The power source 112 is equivalent to the driving power source for the piezoelectric actuator 12.

The circuits 111 and 113 and the power source 112 are connected to the terminals of the wirings and signal lines formed on the flexible wiring board 30. The polarization circuit 113 includes a V _SS3 wiring commonly connected to the lower constant potential electrodes 47 of all ejection energy applying units 40, and a V _SS2 wiring commonly connected to the ground side of the common potential applied to all the driver units 97. A circuit for applying a polarization voltage between the negative power source _VCC2 and the switch SW1. Further, a power supply 112 equivalent to the power supply for performing the above-described discharge operation is connected between the V _DD1 wiring and the V _SS1 wiring and between the V _DD2 wiring and the V _SS2 wiring. At this time, the connection line 70 is not provided between the V _SS3 wiring and the V _SS2 wiring.

Polarization of the piezoelectric layers 23 of all the ejection energy applying units 40 is performed using the circuit having the above-described configuration. When starting the polarization, the switch SW1 is the G side (negative supply _{V CC2} of the side not connected to _{V SS3} wiring), the second potential to the upper constant electric potential electrode 46 through the _{V DD2 wiring, V DD3} wiring (For example, 30V) is given.

In this state, the reset signal of the shift register 106 and the D flip-flop 107 is set to H, and all the data of the shift register 106 and the D flip-flop 107 are set to the discharge zero state. When the enable signal rises from L to H, the output of the AND gate 108 becomes H, and all the driver circuits 110 start energizing the ejection energy applying unit 40. As a result, a second potential (for example, 30 V) is applied to the individual electrode 42 via the V _DD2 wiring.

Here, when the switch SW1 is switched to the N side, a negative potential (-30V in this case) is applied to the lower constant potential electrode 47 from the negative power supply _VCC2 via the _VSS3 wiring. Accordingly, as shown in FIG. 11, a polarization voltage of 60 V is applied to the second active part 37, and a polarization voltage of 30 V is applied to the third active part 38, so that the second active part 37 and the third active part 38 are applied. These are activated by the first stage polarization. Here, the electric field generated in the third active portion 38 is approximately twice as strong as the electric field generated in the second active portion 37.

Subsequently, when the enable signal applied to the AND gate 108 is switched from H to L, the output of the AND gate 108 becomes L, and all the driver circuits 110 stop energizing the ejection energy applying unit 40. As a result, a first potential (for example, 0 V) is applied to the individual electrode 42 via the _VSS2 wiring. Here, when the switch SW1 is switched to the G side, the first potential is applied to the lower constant potential electrode 47 via the V _SS2 wiring and the V _SS3 wiring. At this time, as shown in FIG. 12, a polarization voltage of 30 V is applied to the first active part 36, and a polarization voltage of 30 V is applied to the third active part 38, and the first active part 36 and the third active part 38 These are activated by the second stage polarization.

  When the energization from the power source 112 is stopped after a predetermined time has elapsed, the voltage applied to the piezoelectric deformation portion of the ejection energy applying portion 40 becomes zero. After the polarization is completed in this way, the polarization device including the polarization circuit 113 and the like is removed from the flexible wiring board 30, the first potential supply line 28 and the first power supply line 31 are connected by the connection line 70, and the droplet discharge head 1. Is attached to the carriage 3 of the inkjet recording apparatus 100.

  As described above, when polarization is performed after the flow path unit 11 and the piezoelectric actuator 12 are joined by soldering, deterioration of polarization can be suppressed. In addition, the voltage used for polarization is generated by lowering the potential of the lower constant potential electrode 47 on the side opposite to the individual electrode 42 that supplies the potential from the drive IC 50 with respect to the discharge power supply voltage. Therefore, it is possible to prevent the drive IC 50 from failing during polarization. Furthermore, by performing polarization in two stages of the first stage and the second stage, the electric field is not canceled at the boundary part between the first active part 36 and the second active part 37. The polarization at is not weakened.

[Embodiment 2]
A second embodiment of the present invention will be described. Compared with the liquid droplet ejection head 1 and the inkjet recording apparatus 100 according to the second embodiment, the surface constant potential electrode 44 of the piezoelectric actuator 12 included in the liquid droplet ejection head 1 is compared with that described in the first embodiment. , 43 and the wiring pattern of the flexible wiring board 30 corresponding thereto are different. Therefore, in the following, only the arrangement of the surface constant potential electrodes 44 and 43 of the piezoelectric actuator 12 and the wiring pattern of the flexible wiring board 30 corresponding thereto will be described, and description of other parts will be omitted.

  First, the configuration of the surface constant potential electrodes 44 and 43 of the piezoelectric actuator 12 will be described. FIG. 13 is a plan view of the piezoelectric actuator according to the second embodiment.

  As shown in FIG. 13, the second connection electrode 44 and the first connection electrode 43 are formed on the upper surface of the piezoelectric actuator 12 along both end edges in the Y direction. The first connection electrodes 43 are respectively arranged at the four corners of the upper surface of the piezoelectric actuator 12, and the second connection electrodes 44 are arranged so as to be sandwiched between two first connection electrodes 43, 43 arranged in the X direction. The second connection electrode 44 is electrically connected to the upper constant potential electrode 46 through a conductive material filled in a through hole penetrating the upper piezoelectric layer 21 in the Z direction. The first connection electrode 43 is electrically connected to the lower constant potential electrode 47 through a conductive material filled in a through hole penetrating the upper piezoelectric layer 21 and the lower piezoelectric layer 22 in the Z direction. .

  Hereinafter, the wiring pattern of the wiring unit 13 will be described. FIG. 14 is a bottom view of the wiring unit according to the second embodiment.

  As shown in FIG. 14, the piezoelectric actuator 12 is joined to the portion of the flexible wiring board 30 surrounded by the two-dot chain line 29 in FIG. 14. The flexible wiring board 30 is provided with a plurality of individual electrode connection lands 60 in the approximate center of the range surrounded by the two-point difference line 29. The constant potential electrode connection lands 32 and 34 are provided on both sides of the plurality of individual electrode connection lands 60 in the Y direction.

  The first connection land 32 is provided on the flexible wiring board 30 at a position corresponding to the first connection electrode 43 of the piezoelectric actuator 12 in the Z direction. In other words, the first connection lands 32 are arranged at the four corners of the range (the range surrounded by the two-dot chain line 29 in FIG. 14) to which the piezoelectric actuator 12 of the flexible wiring board 30 is joined. The constant potential electrode connection land 32 is electrically connected to the first connection electrode 43 of the piezoelectric actuator 12 via the solder bump 63.

  On the other hand, the second connection land 34 is provided at a position corresponding to the second connection electrode 44 of the piezoelectric actuator 12 in the Z direction. That is, the second connection lands 34 are arranged between the groups of the first connection lands 32 arranged along the edge in the Y direction on the flexible wiring board 30. The second connection land 34 is electrically connected to the second connection electrode 44 of the piezoelectric actuator 12 via the solder bump 63.

The flexible wiring board 30 is provided with four first power supply wires 31, 31, extending in the X direction along both end edges in the Y direction. Each first power supply wiring 31 is connected to a group of first connection lands 32 arranged in a distributed manner at the four corners of the range where the piezoelectric actuator 12 of the flexible wiring board 30 is joined. The first power supply wiring 31 is a _VSS3 wiring that _{applies a} first potential (ground potential) to the lower constant potential electrode 47 of the piezoelectric actuator 12.

Further, second power supply wires 33 and 33 extending in the X direction are provided along the inside of the first power supply wire 31 provided on the flexible wiring board 30. A portion of the second power supply wiring 33 protrudes outward at the approximate center in the X direction in the range where the piezoelectric actuator 12 of the flexible wiring board 30 is joined, and a plurality of second connection lands 34 are provided at the protruding portion. Yes. The second power supply wiring 33 is a V _DD3 wiring that _applies a second potential to the upper constant potential electrode 46 of the piezoelectric actuator 12.

The two second power supply wires 33 arranged in the Y direction are connected by a second potential supply line 74 connected to the high potential side input portion of the drive ICs 50, 50. The second potential supply line 74 is a V _DD2 wiring that applies a second potential (drive potential) to the drive ICs 50 and 50.

  On the flexible wiring board 30, the second power supply wiring 33 that applies the second potential to the ejection energy applying unit 40 of the piezoelectric actuator 12 and the second potential supply line 74 that applies the second potential to the driving IC 50 are At least a portion has a common wiring portion. This common wiring portion is a wiring portion from the second power supply wiring 33 until the second potential supply line 74 branches. Thus, when the second power supply wiring 33 and the second potential supply line 74 have a common wiring portion, the number of terminals and connectors connected to these wirings is reduced, which contributes to cost reduction. Can do. Furthermore, since the power supply wiring area in the flexible wiring board 30 can be reduced, the size of the flexible wiring board 30 can be reduced, which can contribute to cost reduction and downsizing.

Furthermore, the low potential side of the drive ICs 50 and 50 along the substantially U-shaped inner side formed by the two second power supply wires 33 and 33 arranged in the Y direction and the second potential supply line 74 connected thereto. A first potential supply line 28 connected to the input unit is wired. A plurality of recording signal input lines 71 having one end connected to the drive IC 50 are arranged further inside the first potential supply line 28. The first potential supply line 28 is _{V SS2} wiring for imparting a first potential (ground potential) to the drive IC50,50. The first potential supply line 28 and the first power supply wiring 31 are electrically connected by a connection line 70 to have a common potential (for example, grounded to 0 V).

  As described above, in the droplet discharge head 1 according to the second embodiment, the second connection electrode 44 and the first connection electrode 44 arranged on the surface of the piezoelectric actuator 12 are compared with the droplet discharge head 1 according to the first embodiment. The position of the connection electrode 43 is reversed. Accordingly, the shapes of the first power supply wiring 31 and the second power supply wirings 33 and 33 formed on the flexible wiring board 30 of the wiring unit 13 are changed. However, the configuration of the drive circuit of the inkjet recording apparatus 100, the operation method of the droplet discharge head 1, and the polarization method of the piezoelectric actuator 12 are the same in the first embodiment and the second embodiment.

In each of the above-described embodiments, the connection line 70 may be provided as a preprinted wiring on the back surface of the FFC 30b (the surface opposite to the surface on which the drive IC 50 is mounted).
Specifically, two wirings that are electrically connected to the first potential supply line 28 and the first power supply wiring 31 through the through holes are formed so as to be positioned close to each other on the back surface of the FFC 30b, and solder or the like is attached to the point. What is necessary is just to comprise so that both can be connected only by doing. According to this, conduction work can be simplified as compared with the case where a jumper wire is retrofitted, and it is possible to reliably avoid a short circuit with other wirings by mistake.

  The present invention can be applied to, for example, a droplet discharge head such as an ink jet head and a droplet discharge apparatus including the droplet discharge head.

1 is a plan view of an ink jet recording apparatus including a droplet discharge head according to an embodiment of the present invention. 2 is an exploded perspective view showing a configuration of a droplet discharge head according to Embodiment 1. FIG. It is a partial cross section figure of the X direction of a head main part. It is a partial cross section figure of the Y direction of a head main part. 3 is a plan view of the piezoelectric actuator according to Embodiment 1. FIG. 4 is a bottom view of the wiring unit according to Embodiment 1. FIG. It is sectional drawing of a wiring unit. It is a drive circuit diagram of an inkjet recording device. It is a timing chart figure of a drive of a discharge energy grant part. It is a circuit diagram of a droplet discharge head at the time of polarization. It is sectional drawing of the piezoelectric actuator of a polarization 1st step. It is sectional drawing of the piezoelectric actuator of a polarization 2nd step. 6 is a plan view of a piezoelectric actuator according to Embodiment 2. FIG. 5 is a bottom view of a wiring unit according to Embodiment 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Droplet discharge head 2 Main body frame 3 Carriage 11 Flow path unit 12 Piezoelectric actuator 13 Wiring unit 15 Head main body 21 Upper piezoelectric layer 22 Lower piezoelectric layer 23 Piezoelectric sheet 24 Substrate 28 First potential supply line ( _VSS2 wiring)
30 Flexible wiring board 31 First power supply wiring ( _VSS3 wiring)
32 First connection land 33 Second power supply wiring (V _DD3 wiring)
34 Second connection land 41 Connection terminal 42 Individual electrode 43 First connection electrode 44 Second connection electrode 50 Driving IC
60 Individual electrode connection land 63 Solder bump 71 Recording signal input line 72 Drive signal output line 74 Second potential supply line (V _DD2 wiring)
Reference Signs List 70 connecting line 81 manifold 82 restricting portion 83 pressure chamber 84 descender hole 85 nozzle 100 ink jet recording apparatus

Claims (5)

A flow path unit having a plurality of individual liquid flow paths from the common liquid chamber to the nozzles via the pressure chamber, and a liquid discharge pressure individually stacked on the flow path unit and individually fixed to the individual liquid flow paths. And a wiring board provided with a drive IC that is bonded to the piezoelectric actuator and that provides the piezoelectric actuator with a drive signal that can take at least a first electric potential and a second electric potential. Because
The piezoelectric actuator is
A plurality of individual electrodes provided corresponding to the plurality of pressure chambers and a plurality of individual electrodes provided corresponding to the plurality of individual electrodes and laminated on the flow path unit side of the plurality of individual electrodes via a first piezoelectric layer A plurality of upper constant potential electrodes that are slightly smaller than the individual electrodes, and a plurality of lower constant potentials provided corresponding to the plurality of individual electrodes and stacked on the upper constant potential electrodes via a second piezoelectric layer. An electrode, a first connection electrode connected to all of the plurality of lower constant potential electrodes, and a second connection electrode connected to all of the plurality of upper constant potential electrodes,
The wiring board is
The plurality of individual electrode connection lands provided corresponding to the plurality of individual electrodes, the first connection land provided corresponding to the first connection electrode, and the second connection electrode For outputting a second connection land, a recording signal input line for inputting a recording signal to the driving IC, and the driving signal generated from the driving IC corresponding to the recording signal to the plurality of individual connection terminals. A plurality of drive signal output lines, a first potential supply line and a second potential supply line for supplying a first potential and a second potential to the drive IC, and a plurality of lower constants connected to the first connection land. A first power supply wiring that applies a first potential to the potential electrode; and a second power supply wiring that is connected to the second connection land and applies a second potential to the plurality of upper constant potential electrodes. ,
On the wiring board, the second potential supply line and the second power supply wiring have at least a common wiring portion, and the first potential supply line and the first power supply wiring have the common wiring portion. The first electric potential supply line and the first power supply wiring are connected to each other, and arranged to be spaced apart from each other.
Droplet discharge head. The first power supply wiring is disposed along an edge of the wiring board,
The common wiring portion of the second power supply line and the second potential supply line is disposed in parallel to the first power supply line,
The droplet discharge head according to claim 1. The first potential supply line is disposed in parallel to the second potential supply line,
The droplet discharge head according to claim 2 . In the piezoelectric actuator,
The plurality of individual electrodes are arranged at a substantially central portion of a surface bonded to the wiring board, and the first connection electrode extends along two opposite edges extending in a first direction of the surface bonded to the wiring board. The second connection electrode is arranged so as to sandwich the first connection electrode from both sides in the first direction at the edges of two opposite sides extending in the first direction where the first connection electrode is provided. ,
In the wiring board,
The first connection land and the second connection land are arranged side by side in the first direction so as to correspond to the first connection electrode and the second connection electrode in a connection range where the piezoelectric actuators are stacked. In addition, the first connection land is disposed inside the first power supply wiring,
The droplet discharge head according to any one of claims 1 to 3. The liquid droplet ejection head according to any one of claims 1 to 4,
A liquid supply source for supplying a colored liquid to the droplet discharge head;
A carriage for holding the droplet discharge head;
A main body frame that supports the carriage in a reciprocating manner;
Droplet discharge device.

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