JP2017118071A - Piezoelectric device and liquid injection head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric device being capable of increasing types of a drive waveform driving a piezoelectric element while being capable of reducing costs, and a liquid injection head.SOLUTION: A piezoelectric device comprises: a piezoelectric element 300 being provided on a substrate 10 and having a first electrode 60, a piezoelectric layer 70 and a second electrode 80; and a drive element 121 supplying a drive signal for driving the piezoelectric element 300. The piezoelectric element 300 has a plurality of active parts 310 interposed between the first electrode 60 and second electrode 80. Any one of the first electrode 60 and second electrode 80 constitutes an individual electrode provided for each of the plurality of active part 310, the other of the first electrode 60 and second electrode 80 constitutes a common electrode being common across the plurality of active parts 310, and the drive element 121 is electrically connected to the common electrode and can apply a voltage to the common electrode.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a piezoelectric device having a piezoelectric element and a liquid ejecting head including the piezoelectric device.

  A typical example of a liquid ejecting head that ejects droplets is an ink jet recording head that ejects ink droplets. The ink jet recording head includes, for example, a flow path forming substrate in which a pressure generating chamber communicating with a nozzle opening is formed, and a piezoelectric actuator that is a piezoelectric element provided on one surface side of the flow path forming substrate. In addition, there is known a technique in which an ink droplet is ejected from a nozzle opening by causing a pressure change in ink in a pressure generating chamber by a piezoelectric actuator.

  The piezoelectric actuator includes an individual electrode provided individually for each active part and a common electrode provided in common to a plurality of active parts, and supplies a drive signal to the individual electrode, A bias voltage (vbs) is supplied to drive the active part (see, for example, Patent Document 1).

JP 2013-146932 A

  However, although there is a desire to increase the types of drive signals for driving the piezoelectric elements, a dedicated drive circuit or the like is required to increase the types of drive signals supplied to the individual electrodes of the active part, resulting in high costs. There is a problem of becoming.

  Also, by changing the bias voltage applied to the common electrode, the number of types of drive signals applied to the active part can be increased, but a plurality of power supplies must be prepared, resulting in high cost. There is a problem of end.

  Such a problem is not limited to a liquid jet head typified by an ink jet recording head, and similarly exists in other piezoelectric devices.

  In view of such circumstances, it is an object of the present invention to provide a piezoelectric device and a liquid ejecting head that can increase the types of driving waveforms for driving a piezoelectric element and can reduce the cost.

An aspect of the present invention that solves the above problems includes a piezoelectric element that is provided on a substrate and includes a first electrode, a piezoelectric layer, and a second electrode, and a driving element that supplies a driving signal for driving the piezoelectric element. And the piezoelectric element has a plurality of active portions sandwiched between the first electrode and the second electrode, and one of the first electrode and the second electrode is provided for each active portion. And the other one of the first electrode and the second electrode constitutes a common electrode common to the plurality of active portions, and the driving element is electrically connected to the common electrode. The piezoelectric device is characterized in that a voltage can be applied to the common electrode.
In such an aspect, by applying a voltage from the drive element to the common electrode, a plurality of drive signals from the drive element to the active part can be provided without increasing the drive signal supplied to the individual electrodes and without increasing the power supply supplied to the common electrode. It is possible to supply different types of drive signals.

  Here, the drive element is electrically connected to each of the plurality of individual electrodes via a drive signal line, and the drive element is electrically connected to the common electrode via the drive signal line. It is preferable. According to this, a voltage can be applied to the common electrode from the drive circuit via the drive signal line.

  Moreover, it is preferable that at least one of the individual electrodes and the common electrode are electrically connected on the substrate. According to this, a voltage can be applied to a common electrode from a drive element via an individual electrode.

  The drive element is mounted on a wiring board, and the wiring board is provided with the drive signal line and a power line electrically connected to the common electrode. Preferably, at least one of the drive signal lines and the power supply line are electrically connected. According to this, a voltage can be applied to the common electrode from the drive element via the power supply line.

According to another aspect of the invention, there is provided a liquid ejecting head including the piezoelectric device according to the above aspect.
In this aspect, the print quality can be improved by reducing the cost and selecting a plurality of drive signals for driving the active portion.

FIG. 2 is an exploded perspective view of a recording head according to Embodiment 1 of the invention. FIG. 3 is a plan view of a main part of the recording head according to the first embodiment of the invention. FIG. 3 is a cross-sectional view of the recording head according to the first embodiment of the invention. FIG. 3 is a cross-sectional view of the recording head according to the first embodiment of the invention. It is a top view of the flexible cable which concerns on Embodiment 1 of this invention. It is a drive waveform which shows the drive signal which concerns on Embodiment 1 of this invention. It is a graph which shows the relationship between a voltage and the amount of displacement in Embodiment 1 of the present invention. FIG. 6 is a cross-sectional view of a recording head according to Embodiment 2 of the invention. FIG. 6 is a plan view of a main part of a recording head according to Embodiment 3 of the invention. 1 is a schematic diagram of a recording apparatus according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
FIG. 1 is an exploded perspective view of an ink jet recording head that is a liquid ejecting head according to Embodiment 1 of the present invention, FIG. 2 is a plan view of a main part of a flow path forming substrate of the recording head, and FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. 2, FIG. 4 is a cross-sectional view taken along the line BB ′ of FIG. 2, and FIG. 5 is a plan view of the flexible cable.

  As shown in the drawing, the flow path forming substrate 10 which is the substrate of the present embodiment constituting the ink jet recording head 1 (hereinafter also simply referred to as the recording head 1) of the present embodiment is anisotropically etched from one surface side. As a result, the pressure generating chambers 12 partitioned by the plurality of partition walls 11 are arranged side by side along the direction in which the plurality of nozzle openings 21 for discharging ink are arranged in parallel. Hereinafter, this direction is referred to as a direction in which the pressure generating chambers 12 are arranged side by side or a first direction X. Further, the flow path forming substrate 10 is provided with a plurality of rows in which the pressure generation chambers 12 are arranged in parallel in the first direction X, and in this embodiment, two rows. An arrangement direction in which a plurality of rows of the pressure generating chambers 12 are arranged is hereinafter referred to as a second direction Y. Furthermore, a direction orthogonal to both the first direction X and the second direction Y is referred to as a third direction Z. In detail, the case member 40 side described later is referred to as a Z1 side, and the nozzle plate 20 side is referred to as a Z2 side. The first direction X, the second direction Y, and the third direction Z are directions orthogonal to each other, but are not particularly limited thereto, and may be directions that intersect at an angle other than orthogonal. .

  A communication plate 15 and a nozzle plate 20 are sequentially stacked on the Z2 side surface of the flow path forming substrate 10.

  The communication plate 15 is provided with a nozzle communication path 16 that communicates the pressure generation chamber 12 and the nozzle opening 21. The communication plate 15 has a larger area than the flow path forming substrate 10, and the nozzle plate 20 has a smaller area than the flow path forming substrate 10. By providing the communication plate 15 in this manner, the nozzle opening 21 of the nozzle plate 20 and the pressure generating chamber 12 can be separated from each other, so that the ink in the pressure generating chamber 12 is contained in the ink generated by the ink near the nozzle opening 21. Less susceptible to thickening due to moisture evaporation. Further, since the nozzle plate 20 only needs to cover the opening of the nozzle communication passage 16 that communicates the pressure generating chamber 12 and the nozzle opening 21, the area of the nozzle plate 20 can be made relatively small, and the cost can be reduced. be able to. In the present embodiment, a surface on which the nozzle openings 21 of the nozzle plate 20 are opened and ink droplets are ejected is referred to as a liquid ejecting surface 20a.

The communication plate 15 is provided with a first manifold portion 17 and a second manifold portion 18 that constitute a part of the manifold 100.
The first manifold portion 17 is provided through the communication plate 15 in the third direction Z.

  Further, the second manifold portion 18 is provided to open to the nozzle plate 20 side of the communication plate 15 without penetrating the communication plate 15 in the third direction Z.

  Further, the communication plate 15 is provided with a supply communication passage 19 that communicates with one end portion in the second direction Y of the pressure generation chamber 12 independently of each of the pressure generation chambers 12. The supply communication path 19 communicates the second manifold portion 18 and the pressure generation chamber 12. That is, the supply communication path 19 is arranged in parallel with the manifold 100 in the first direction X.

  In the nozzle plate 20, nozzle openings 21 communicating with the pressure generation chambers 12 through the nozzle communication passages 16 are formed. That is, nozzle openings 21 that eject the same type of liquid (ink) are juxtaposed in the first direction X, and the rows of nozzle openings 21 juxtaposed in the first direction X are in the second direction. Two rows are formed in Y.

  On the other hand, a diaphragm 50 is formed on the surface of the flow path forming substrate 10 on the Z1 side. In the present embodiment, an elastic film 51 made of silicon oxide provided on the flow path forming substrate 10 side and an insulator film 52 made of zirconium oxide provided on the elastic film 51 are provided as the diaphragm 50. I made it. The liquid flow path such as the pressure generation chamber 12 is formed by anisotropically etching the flow path forming substrate 10 from one side (the side where the nozzle plate 20 is bonded). The other surface is defined by an elastic film 51.

  In addition, the first electrode 60, the piezoelectric layer 70, and the second electrode 80 are laminated on the diaphragm 50 of the flow path forming substrate 10 by film formation and lithography to form the piezoelectric actuator 300. In the present embodiment, the piezoelectric actuator 300 serves as a pressure generating unit that causes a pressure change in the ink in the pressure generating chamber 12. Here, the piezoelectric actuator 300 is also referred to as a piezoelectric element 300 and refers to a portion including the first electrode 60, the piezoelectric layer 70, and the second electrode 80. A portion where piezoelectric distortion occurs in the piezoelectric layer 70 when a voltage is applied between the first electrode 60 and the second electrode 80 is referred to as an active portion 310. In this embodiment, as will be described in detail later, an active portion 310 is formed for each pressure generation chamber 12. That is, a plurality of active portions 310 are formed on the flow path forming substrate 10. In general, any one electrode of the active part 310 is configured as a common electrode common to the plurality of active parts 310, and the other electrode is configured as an individual electrode independent for each active part 310. In the present embodiment, the first electrode 60 is an individual electrode and the second electrode 80 is a common electrode, but this may be reversed. In the above-described example, the diaphragm 50 and the first electrode 60 act as a diaphragm. However, the present invention is not limited to this. For example, the diaphragm 50 is not provided, and only the first electrode 60 vibrates. You may make it act as a board. Further, the piezoelectric actuator 300 itself may substantially serve as a diaphragm.

  Here, the piezoelectric actuator 300 of this embodiment will be described in more detail. The first electrode 60 constituting the piezoelectric actuator 300 is separated for each pressure generation chamber 12 and constitutes an individual electrode independent for each active part 310 that is a substantial driving part of the piezoelectric actuator 300. The first electrode 60 is formed with a width narrower than the width of the pressure generation chamber 12 in the second direction Y of the pressure generation chamber 12. That is, in the first direction X of the pressure generation chamber 12, the end portion of the first electrode 60 is located inside the region facing the pressure generation chamber 12. In the second direction Y, both end portions of the first electrode 60 are extended to the outside of the pressure generation chamber 12.

  The piezoelectric layer 70 is continuously provided in the first direction X so that the second direction Y has a predetermined width. The width of the piezoelectric layer 70 in the second direction Y is wider than the length of the pressure generation chamber 12 in the second direction Y. Therefore, in the second direction Y of the pressure generation chamber 12, the piezoelectric layer 70 is provided to the outside of the pressure generation chamber 12.

  In the second direction Y of the pressure generating chamber 12, the end of the piezoelectric layer 70 on the ink supply path side is located outside the end of the first electrode 60. That is, the end portion of the first electrode 60 is covered with the piezoelectric layer 70. The end of the piezoelectric layer 70 on the nozzle opening 21 side is located on the inner side (pressure generation chamber 12 side) of the end of the first electrode 60, and the end of the first electrode 60 on the nozzle opening 21 side. The portion is not covered with the piezoelectric layer 70.

The piezoelectric layer 70 is made of a piezoelectric material of the oxide having a polarization structure formed on the first electrode 60, for example, it may consist of a perovskite oxide represented by the general formula ABO _3, lead containing lead For example, a lead-based piezoelectric material or a lead-free piezoelectric material containing no lead can be used.

  In such a piezoelectric layer 70, recesses 71 corresponding to the respective partition walls are formed. The width of the recess 71 in the first direction X is substantially the same as or wider than the width of each partition wall in the first direction. As a result, the rigidity of the portion (the so-called arm portion of the diaphragm 50) that opposes the end of the pressure generation chamber 12 of the diaphragm 50 in the second direction Y is suppressed, so that the piezoelectric actuator 300 can be displaced favorably. it can.

  The second electrode 80 is provided on the opposite surface side of the piezoelectric layer 70 from the first electrode 60 and constitutes a common electrode common to the plurality of active portions 310. Further, the second electrode 80 may or may not be provided on the inner surface of the recess 71, that is, on the side surface of the recess 71 of the piezoelectric layer 70.

  Here, as shown in FIG. 4, among the pressure generation chambers 12, one or more pressure generation chambers 12 provided at both ends in the first direction X are dummy that is not actually used for discharging ink droplets. It is a pressure generation chamber 12B. That is, the pressure generating chamber 12 includes a pressure generating chamber 12A used for discharging ink droplets, and a dummy pressure generating chamber 12B that is not used for discharging ink droplets provided on both ends of the pressure generating chamber 12A in the juxtaposed direction. And divided. In the present embodiment, a total of four dummy pressure generating chambers 12B are provided, two at each end portion in the first direction X. The region corresponding to the dummy pressure generation chamber 12B includes the first electrode 60, the piezoelectric layer 70, and the second electrode 80 similarly to the active portion 310, but the inactive portion 320 that does not function as the active portion 310. Is provided. That is, a total of four inactive portions 320 are provided, two at each end of the active portion 310 arranged in parallel in the first direction X.

  The inactive part 320 includes the first electrode 60, the piezoelectric layer 70, and the second electrode 80. The first electrode 60 is provided independently for each pressure generation chamber 12 as with the first electrode 60 of the active part 310. Further, the piezoelectric layer 70 is formed continuously from the active portion 310, and similarly to the active portion 310, a recess 71 is provided between the active portion 310 and between the inactive portion 320. Yes. Further, the second electrode 80 is provided continuously from the active part 310. A connection hole 72 penetrating in the third direction Z is provided in the piezoelectric layer 70 of the inactive portion 320. The second electrode 80 is electrically connected to the first electrode 60 in the connection hole 72 through the connection hole 72 of the inactive portion 320. That is, in the inactive portion 320, the first electrode 60 and the second electrode 80 are in an electrically shorted state. Thereby, in the non-active part 320, when a potential is applied to the first electrode 60, a potential is applied to the second electrode 80.

  Further, an individual wiring 91 that is a lead-out wiring is led out from the first electrode 60 of the piezoelectric actuator 300. Further, from the second electrode 80, a common wiring 92 that is a lead-out wiring is drawn out. Further, the flexible cable 120 is connected to the extended ends of the individual wiring 91 and the common wiring 92 opposite to the ends connected to the piezoelectric actuator 300.

  The flexible cable 120 is a flexible wiring board, and in this embodiment, a drive circuit 121 that is a drive element is mounted. As shown in FIG. 5, the flexible cable 120 is provided with a drive signal line 122 connected to the individual wiring 91 and a power supply line 123 connected to the common wiring 92. Further, the flexible cable 120 is provided with an input wiring 124 having one end connected to the drive circuit 121 and extending to the end opposite to the drive signal line 122. The input wiring 124 is a head such as a setting signal including a drive signal (COM), a clock signal (CLK), a latch signal (LAT), a change signal (CH), pixel data (SI), setting data (SP), and the like. This is for supplying a control signal to the drive circuit 121. In the drive circuit 121, for example, a switching element such as a transmission gate is provided for each piezoelectric actuator 300. Based on the head control signal input by the input wiring 124, the switching element is opened and closed, and desired The drive signal is generated at the timing. The drive signal generated by the drive circuit 121 is supplied to the first electrode 60 of the piezoelectric actuator 300 via the drive signal line 122 and the individual wiring 91. In the present embodiment, the head control signal supplied to the drive circuit 121 via the input wiring 124 is supplied to the second electrode 80 that is a common electrode by controlling the power supplied to the inactive portion 320. A control signal for adjusting a drive signal generated by changing the bias voltage (vbs) is also included.

  Further, the power line 123 provided in the flexible cable 120 is not connected to the drive circuit 121, and is connected from the one end where the input wiring 124 of the flexible cable 120 is provided to the other end where the drive signal line 122 is provided. It is provided continuously over. A bias voltage (vbs) is applied from the power supply line 123 to the second electrode 80 through the common wiring 92.

  In this embodiment, since the inactive part 320 in which the first electrode 60 and the second electrode 80 are short-circuited is provided, the drive signal line 122 connected to the first electrode 60 of the inactive part 320 is connected to the second electrode. 80 is electrically connected. That is, as shown in FIG. 5, among the drive signal lines 122 of the drive circuit 121, the drive signal line 122A is electrically connected to the active part 310, and the drive signal line 122B is connected to the second electrode via the inactive part 320. 80 is electrically connected.

  Therefore, the second electrode 80 is supplied with the first bias voltage supplied from the power supply line 123 and the second bias voltage supplied from the drive circuit 121 from the drive signal line 122B and the inactive part 320. The The second bias voltage is selectively supplied by the drive circuit 121 based on a control signal supplied via the input wiring 124. That is, in this embodiment, since the four inactive portions 320 are provided for the row of the active portions 310 of the piezoelectric actuator 300, the second bias is supplied by selectively supplying voltages to the four inactive portions 320. The voltage value of the voltage can be varied. That is, the second electrode 80 is supplied with the first bias voltage and five different types of second bias voltages that are selectively supplied to zero to four of the four inactive portions 320. It can be selectively applied. Accordingly, five different bias voltages can be supplied to the second electrode 80.

  As a method for supplying the second bias voltage from the drive circuit 121, for example, as a drive signal (COM) supplied from the input wiring 124 to the drive circuit 121, an ejection drive signal for ejecting ink droplets and a second drive signal (COM) are used. 2 is supplied to the drive circuit 121 via the input wiring 124, the clock signal (CLK), the latch signal (LAT), the change signal (CH), and the pixel data (SI). Based on the setting data (SP) or the like, voltage supply to the four inactive units 320 may be selectively performed. Accordingly, it is possible to selectively apply a voltage to the inactive portion 320 using the drive circuit 121 used in the conventional recording head 1 without using a special drive circuit 121, thereby reducing the cost. it can. Of course, the method for supplying the second bias voltage from the drive circuit 121 is not particularly limited to this. For example, four power supplies for supplying the drive circuit 121 and driving the drive circuit 121 as the second bias voltage are provided. You may make it selectively supply to the inactive part 320. FIG.

  In this way, by changing the bias voltage supplied to the second electrode 80, two or more types of drive signals are substantially generated by the drive circuit 121 without using a plurality of types of power supplied via the power line 123. Can be generated.

  Here, a drive waveform indicating a drive signal generated by the drive circuit will be described with reference to FIG. FIG. 6 shows a drive waveform indicating a drive signal.

Driving waveform shown in FIG. 6 is a waveform for ejecting the ink droplets from the nozzle openings 21, the driving waveforms applied to the first electrode 60 is an individual electrode, is applied from the reference potential V ₀ which until the electric potential V ₁ an expansion element P1 for expanding the pressure generating chamber 12 Te, an expansion maintaining element P2 maintaining the expanded state a predetermined time, contraction element for contracting the pressure generating chamber 12 is applied from the electric potential V ₁ to the second potential V ₂ and P3, comprises a contraction maintaining element P4 to maintain a contracted state a certain time, an expansion return element P5 for returning the pressure generating chamber 12 from the second contracted state of the potential V ₂ to the reference volume of the reference potential V _0, a. Such P1 to P5 are repeated at a constant cycle.

The driving waveforms applied to the second electrode 80 is a common electrode is a waveform applied across the period of the P1~P5 the first bias voltage as the bias voltage vbs _1. By adding a second bias voltage to such a bias voltage vbs ₁ , both the first bias voltage and the second bias voltage are applied to the second electrode 80 as the bias voltage vbs _2. .

Thus, by appropriately changing to the bias voltage vbs ₁ and the bias voltage vbs ₂ applied to the second electrode 80 that is the common electrode, the drive signal supplied to the first electrode 60 that is the individual electrode can be changed without being changed. The drive signal applied to the unit 310 can be changed.

That is, as shown in FIG. 7, in the butterfly curve showing the relationship between the voltage and the electric field induced strain (displacement amount), when ΔV is applied to the piezoelectric layer 70 of the active portion 310, the bias applied to the second electrode 80 By changing the voltage from vbs ₁ to vbs ₂ , it is possible to change the amount of displacement of the active part 310 from d ₁ to d ₂ by changing the portion used by the butterfly curve. In the example shown in FIG. 7, the displacement amount d ₂ when the bias voltage vbs ₂ is applied is larger than the displacement amount d ₁ when the bias voltage vbs ₁ is applied, and the ejection characteristics are improved. be able to. Of course, the present invention is not particularly limited to this. For example, the displacement d ₂ when the bias voltage vbs ₂ is applied may be smaller than the displacement d ₁ . This is because, for example, the part of the butterfly curve used when the bias voltage vbs ₁ is applied according to the values of the bias voltages vbs ₁ , vbs ₂ , the reference potentials V ₀ , V ₁ , V ₂ applied to the first electrode 60, etc. And the part of the butterfly curve used when the bias voltage vbs ₂ is applied.

In FIG. 7, the bias voltage vbs ₁ 2 types of displacement _d 1 was changed to the bias voltage vbs ₂ a, _{d 2} has been illustrated, in this embodiment, four different bias of five types by the non-active portion 320 Since a voltage can be applied to the second electrode 80, the amount of displacement of the active portion 310 can be changed to five types depending on the type of the bias voltage.

  Thus, since the bias voltage applied to the second electrode 80 can be changed via the drive circuit 121, different drive signals can be applied to the active portion 310, and a plurality of types of ink droplets having different ejection characteristics can be applied. Can be discharged. Therefore, increasing the dot selectivity at the time of printing can improve the graininess, gradation and color development of the printed matter. In addition, since a different drive signal can be applied to the active unit 310 by changing the bias voltage applied to the second electrode 80 via the drive circuit 121, the first bias voltage supplied via the power supply line 123. Without supplying a plurality of power supply devices or variable power supplies, supplying a plurality of different drive signals to the drive circuit 121 via the input wiring 124, or causing the drive circuit 121 to select a plurality of different drive signals in a complicated manner. There is no need and the cost can be reduced.

  A protective substrate 30 having substantially the same size as the flow path forming substrate 10 is bonded to the surface of the flow path forming substrate 10 on the Z1 side. The protective substrate 30 has a holding portion 31 that is a space for protecting the piezoelectric actuator 300. Two holding portions 31 are formed side by side in the second direction Y between the rows of piezoelectric actuators 300 arranged in parallel in the first direction X. Further, the protective substrate 30 is provided with a through hole 32 penetrating in the third direction Z between two holding portions 31 arranged in parallel in the second direction Y. The ends of the individual wiring and the common wiring 92 drawn out from the electrodes of the piezoelectric actuator 300 are extended so as to be exposed in the through hole 32, and the individual wiring 91 and the common wiring 92 and the drive signal line 122 of the flexible cable 120 are extended. And the power line 123 are electrically connected within the through hole 32. In addition, the connection method of the individual wiring 91 and the common wiring 92, and the drive signal line 122 and the power supply line 123 of the flexible cable 120 is not particularly limited. For example, soldering or brazing such as soldering or eutectic bonding , Welding, conductive adhesive containing conductive particles (ACP, ACF), non-conductive adhesive (NCP, NCF) and the like.

  On the protective substrate 30, a case member 40 that fixes the manifold 100 communicating with the plurality of pressure generating chambers 12 together with the flow path forming substrate 10 is fixed. The case member 40 has substantially the same shape as the communication plate 15 described above in a plan view, and is bonded to the protective substrate 30 and is also bonded to the communication plate 15 described above. Specifically, the case member 40 has a recess 41 having a depth in which the flow path forming substrate 10 and the protective substrate 30 are accommodated on the protective substrate 30 side. The concave portion 41 has an opening area larger than the surface of the protective substrate 30 bonded to the flow path forming substrate 10. The opening surface on the nozzle plate 20 side of the recess 41 is sealed by the communication plate 15 in a state where the flow path forming substrate 10 and the like are accommodated in the recess 41. As a result, the third manifold portion 42 is defined by the case member 40 and the flow path forming substrate 10 on the outer periphery of the flow path forming substrate 10. Then, the first manifold portion 17 and the second manifold portion 18 provided on the communication plate 15, and the third manifold portion 42 defined by the case member 40 and the flow path forming substrate 10, the manifold of this embodiment. 100 is configured. The manifold 100 is continuously provided in the first direction X, which is the direction in which the pressure generation chambers 12 are arranged, and the supply communication path 19 that communicates each pressure generation chamber 12 and the manifold 100 is the first. Are arranged side by side in the direction X.

  A compliance substrate 45 is provided on the Z2 side surface of the communication plate 15 where the first manifold portion 17 and the second manifold portion 18 open. The compliance substrate 45 seals the openings of the first manifold portion 17 and the second manifold portion 18 on the liquid ejection surface 20a side. In this embodiment, the compliance substrate 45 includes a sealing film 46 made of a flexible thin film and a fixed substrate 47 made of a hard material such as metal. Since the region facing the manifold 100 of the fixed substrate 47 is an opening 48 that is completely removed in the thickness direction, one surface of the manifold 100 is sealed only with a flexible sealing film 46. The compliance portion 49 is a flexible portion.

  The case member 40 is provided with an introduction path 44 that communicates with the manifold 100 and supplies ink to each manifold 100. The case member 40 is provided with a connection port 43 through which the flexible cable 120 is inserted in communication with the through hole 32 of the protective substrate 30.

  In such a recording head 1, when ink is ejected, the ink is taken in from the introduction path 44 and the inside of the flow path is filled with ink from the manifold 100 to the nozzle opening 21. Thereafter, according to the signal from the drive circuit 121, the diaphragm 50 is deformed together with the active portion 310 by applying a voltage to each active portion 310 corresponding to the pressure generating chamber 12 (12A). As a result, the pressure in the pressure generating chamber 12 (12A) is increased and ink droplets are ejected from the predetermined nozzle openings 21.

(Embodiment 2)
FIG. 8 is a cross-sectional view of the main part of a recording head according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the member similar to embodiment mentioned above, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 8, the inactive portion 320 provided in the region corresponding to the dummy pressure generating chamber 12 </ b> B of the present embodiment is not provided with the piezoelectric layer 70. That is, the first electrode 60 and the second electrode 80 are provided in a region corresponding to the dummy pressure generation chamber 12B, and the first electrode 60 and the second electrode 80 are electrically connected. Even with such a configuration, the drive signal line 122 </ b> B connected to the drive circuit 121 can be electrically connected to the second electrode 80 via the inactive portion 320.

(Embodiment 3)
FIG. 9 is a plan view of the drive wiring according to the third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member similar to Embodiment 1 mentioned above, and the overlapping description is abbreviate | omitted.

  As shown in FIG. 9, the flexible cable 120 of the present embodiment is provided with a drive circuit 121, a drive signal line 122 connected to the drive circuit 121, a power supply line 123, and an input wiring 124.

  The plurality of drive signal lines 122 are divided into a drive signal line 122A electrically connected to the active portion 310 and a drive signal line 122B electrically connected to the power supply line 123 on the flexible cable 120.

  That is, although not particularly illustrated, the non-active portion 320 is not formed on the flow path forming substrate 10, but only the active portion 310 is formed, and the drive signal line 122B is formed in the above-described first embodiment. 2 and 2, without being connected to the second electrode 80 on the flow path forming substrate 10, it is electrically connected to the power line 123 on the flexible cable 120. Thus, even if the drive signal line 122B is electrically connected to the power line 123 on the flexible cable 120, the power line 123 is electrically connected to the second electrode 80 that is a common electrode of the plurality of active portions 310. Therefore, the second bias voltage from the drive circuit 121 can be supplied to the second electrode 80 via the drive signal line 122B and the power supply line 123.

  In such a configuration, since the bias voltage applied to the second electrode 80 can be changed via the drive circuit 121, different drive signals can be applied to the active part 310, and a plurality of types having different ejection characteristics can be applied. Ink droplets can be ejected. Therefore, increasing the dot selectivity at the time of printing can improve the graininess, gradation and color development of the printed matter. In addition, since a different drive signal can be applied to the active unit 310 by changing the bias voltage applied to the second electrode 80 via the drive circuit 121, the first bias voltage supplied via the power supply line 123. Without supplying a plurality of power supply devices or variable power supplies, supplying a plurality of different drive signals to the drive circuit 121 via the input wiring 124, or causing the drive circuit 121 to select a plurality of different drive signals in a complicated manner. There is no need and the cost can be reduced. In particular, in the present embodiment, it is possible to change the bias voltage applied to the second electrode 80 via the drive circuit 121 only by changing the flexible cable 120, so that the active portion 310 of the flow path forming substrate 10 is not connected. It is not necessary to form the active part 320, and the flow path forming substrate 10 on which the conventional active part 310 is formed can be used. Therefore, it is not necessary to change the manufacturing process of the flow path forming substrate 10 and the piezoelectric actuator 300, the mask pattern, etc., and the cost can be reduced.

(Other embodiments)
As mentioned above, although each embodiment of this invention was described, the fundamental structure of this invention is not limited to what was mentioned above.

  For example, in the first and second embodiments described above, the inactive portion 320 is provided in a region corresponding to the dummy pressure generating chamber 12B. However, the present invention is not particularly limited thereto. For example, the dummy pressure generating chamber 12B is not provided. The inactive portion 320 may be provided. However, the provision of the dummy pressure generation chamber 12B causes variations in the production of the pressure generation chamber 12A, that is, variations in the shapes of the pressure generation chamber 12A at the center and the pressure generation chamber 12A at the end in the juxtaposed direction. Can be suppressed.

  In the first and second embodiments described above, four inactive portions 320 are provided, and in the third embodiment, four drive signal lines 122B are provided. However, the number of inactive portions 320 and the number of drive signal lines 122B are not limited. The number is not limited to those described above, and may be one or more than two.

  Furthermore, in Embodiments 1 and 2 described above, the widths of the active part 310 and the inactive part 320 in the first direction X are the same, but the present invention is not particularly limited thereto, and the first part of the inactive part 320 is not limited thereto. The width in the direction X may be larger than that of the active part 310. Here, increasing the width of the inactive portion 320 in the first direction X means that the width of the inactive portion 320 in the first direction X is larger than the width of the first electrode 60 of the active portion 310, It means that the width of the connection hole 72 is also increased. Accordingly, the contact area between the first electrode 60 and the second electrode 80 can be increased, and the second bias voltage can be reliably applied to the second electrode 80.

  Further, in the first and second embodiments described above, the first electrode 60 and the second electrode 80 are directly in contact with each other in the inactive portion 320. However, the present invention is not limited to this. A piezoelectric layer 70 thinner than the piezoelectric layer 70 of the active part 310 may be formed between the first electrode 60 and the second electrode 80. Thus, even if the piezoelectric layer 70 is left thin in the inactive portion 320, the first electrode 60 and the second electrode 80 can be electrically connected, and the piezoelectric layer 70 remains thick. Accordingly, the amount of current supplied from the first electrode 60 to the second electrode 80 can be controlled, and the bias voltage applied to the second electrode 80 can be freely controlled. Of course, you may make it provide simultaneously the inactive part 320 which removed the piezoelectric material layer 70 completely, and the inactive part 320 which left the piezoelectric material layer 70 thinly.

  Moreover, in each embodiment mentioned above, although the drive circuit 121 was provided in the flexible cable 120, it is not limited to this in particular, For example, you may make it provide the drive circuit 121 in the protective substrate 30. FIG. When the drive circuit 121 is provided on the protective substrate 30 as described above, the protective substrate 30 corresponds to the wiring substrate. Therefore, in order to realize the same configuration as that of the third embodiment, the wiring provided on the protective substrate 30 is provided. In this case, the power supply line 123 and the drive signal line 122B may be electrically connected.

  Further, in each of the above-described embodiments, the piezoelectric element that causes a pressure change in the pressure generation chamber 12 has been described using the thin film type piezoelectric actuator 300. However, the present invention is not particularly limited thereto, and, for example, a green sheet is pasted. For example, a thick film type piezoelectric actuator formed by a method such as the above, a longitudinal vibration type piezoelectric actuator in which piezoelectric materials and electrode forming materials are alternately stacked and expanded and contracted in the axial direction can be used.

  Such a recording head 1 is mounted on an ink jet recording apparatus I. FIG. 10 is a schematic diagram illustrating an example of an ink jet recording apparatus according to the present embodiment.

  In the ink jet recording apparatus I shown in FIG. 10, the recording head 1 is provided with a cartridge 2 constituting a liquid supply means in a detachable manner, and a carriage 3 on which the recording head 1 is mounted is a carriage attached to the apparatus main body 4. The shaft 5 is provided so as to be movable in the axial direction.

  Then, the driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), so that the carriage 3 on which the recording head 1 is mounted is moved along the carriage shaft 5. On the other hand, the apparatus main body 4 is provided with a conveyance roller 8 as a conveyance means, and a recording sheet S which is a recording medium such as paper is conveyed by the conveyance roller 8. Note that the conveyance means for conveying the recording sheet S is not limited to the conveyance roller, and may be a belt, a drum, or the like.

  In the above-described example, the ink jet recording apparatus I has a configuration in which the cartridge 2 as the ink supply unit is mounted on the carriage 3. However, the invention is not particularly limited thereto, and for example, a liquid supply unit such as an ink tank is used. The liquid supply means and the recording head 1 may be connected to each other via a supply pipe such as a tube by being fixed to the apparatus main body 4. Further, the liquid supply means may not be mounted on the ink jet recording apparatus.

  Further, in the above-described ink jet recording apparatus I, the recording head 1 is mounted on the carriage 3 and exemplarily moves in the main scanning direction. However, the present invention is not particularly limited thereto. For example, the recording head 1 is fixed, The present invention can also be applied to a so-called line type recording apparatus that performs printing only by moving a recording sheet S such as paper in the sub-scanning direction.

  In addition, the present invention is intended for a wide range of liquid ejecting heads in general, for example, for manufacturing recording heads such as various ink jet recording heads used in image recording apparatuses such as printers, and color filters such as liquid crystal displays. The present invention can also be applied to a coloring material ejecting head, an organic EL display, an electrode material ejecting head used for forming electrodes such as an FED (field emission display), a bioorganic matter ejecting head used for biochip manufacturing, and the like. Further, although the ink jet recording apparatus I has been described as an example of the liquid ejecting apparatus, the liquid ejecting apparatus using the other liquid ejecting heads described above can also be used.

  The present invention is widely intended for piezoelectric devices, and can be applied to piezoelectric devices other than recording heads. Examples of such a piezoelectric device include an ultrasonic device, a motor, a pressure sensor, a pyroelectric element, and a ferroelectric element. Further, a completed body using these piezoelectric devices, for example, a liquid ejecting apparatus using the recording head, an ultrasonic sensor using the ultrasonic device, a robot using the motor as a driving source, the pyroelectric element Also included in the piezoelectric device are an IR sensor using a ferroelectric layer and a ferroelectric memory using a ferroelectric element.

  DESCRIPTION OF SYMBOLS I ... Inkjet recording device (liquid ejecting apparatus), 1 ... Inkjet recording head (liquid ejecting head), 2 ... Cartridge, 10 ... Channel formation substrate (substrate), 11 ... Partition, 12, 12A ... Pressure generating chamber, 12B ... dummy pressure generating chamber, 20 ... nozzle plate, 21 ... nozzle opening, 30 ... protective substrate, 40 ... case member, 45 ... compliance substrate, 50 ... vibration plate, 60 ... first electrode, 70 ... piezoelectric layer, 71 Recess, 72 ... Connection hole, 80 ... Second electrode, 91 ... Individual wiring, 92 ... Common wiring, 100 ... Manifold, 120 ... Flexible cable, 121 ... Drive circuit, 122, 122A, 122B ... Drive signal line, 123 ... Power line, 124 ... input wiring, 300 ... piezoelectric actuator (piezoelectric element), 310 ... active part, 320 ... inactive part

Claims (5)

A piezoelectric element provided on a substrate and having a first electrode, a piezoelectric layer, and a second electrode;
A drive element for supplying a drive signal for driving the piezoelectric element,
The piezoelectric element has a plurality of active portions sandwiched between the first electrode and the second electrode,
Either one of the first electrode and the second electrode constitutes an individual electrode provided for each active part,
Either one of the first electrode and the second electrode constitutes a common electrode common to the plurality of the active portions,
The piezoelectric element is characterized in that the driving element is electrically connected to the common electrode and can apply a voltage to the common electrode. The drive element is electrically connected to the plurality of individual electrodes via drive signal lines, respectively.
The piezoelectric device according to claim 1, wherein the drive element is electrically connected to the common electrode via the drive signal line.   The piezoelectric device according to claim 1, wherein at least one of the individual electrodes and the common electrode are electrically connected on the substrate. The drive element is mounted on a wiring board,
The wiring board is provided with the drive signal line and a power line electrically connected to the common electrode,
The piezoelectric device according to claim 2, wherein at least one of the drive signal lines and the power supply line are electrically connected on the wiring board.   A liquid ejecting head comprising the piezoelectric device according to claim 1.

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