Liquid discharge head and liquid discharge device

Abstract

To provide a liquid discharge head that can detect pressure of an absorption chamber in the vicinity of a pressure chamber.SOLUTION: The liquid discharge head comprises: a nozzle substrate provided with a nozzle that discharges liquid; a pressure chamber substrate that includes a pressure chamber in which pressure for making the nozzle discharge liquid is applied to liquid and an absorption chamber that is adjacent to the pressure chamber and that absorbs vibration of liquid that is generated when pressure is applied to liquid in the pressure chamber; a first piezoelectric substance, provided to correspond to the pressure chamber, which is applied with voltages to apply pressure to the pressure chamber; a second piezoelectric substance provided to correspond to the absorption chamber; and a pressure obtaining part that obtains pressure of the absorption chamber, on the basis of voltages acting on the second piezoelectric substance.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a liquid ejection head and a liquid ejection apparatus. [Background technology]

[0002] Liquid ejection devices equipped with multiple heads that eject liquid such as ink onto a medium such as printing paper have been proposed. In recent years, inkjet printers have been attracting attention not only for printing purposes but also as devices that can apply liquefied materials to any location. Inkjet printers are equipped with liquid ejection heads that eject liquid. As a liquid ejection head, a head that ejects liquid filled in a pressure chamber from a nozzle by vibrating a vibration plate that constitutes the wall surface of the pressure chamber using a piezoelectric element is known.

[0003] The liquid ejection head described in Patent Document 1 has a pressure chamber and a liquid storage chamber provided at a position different from the pressure chamber. By providing the liquid storage chamber, pressure fluctuations caused by the liquid can be effectively absorbed, thereby improving the stability of ejection of liquid from the nozzles. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-153926 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the liquid ejection head described in Patent Document 1, the pressure chamber and the liquid storage chamber are provided at positions separated from each other via many members. Therefore, the efficiency of absorbing liquid vibrations in the pressure chamber is low. It is believed that the efficiency of absorbing liquid vibrations can be improved by providing a liquid storage chamber at a position adjacent to the pressure chamber.

[0006] However, in a liquid ejection head, the behavior of the liquid changes significantly depending on the pressure of the pressure chamber. For this reason, acquiring the pressure has been a challenge. The inventors have discovered a configuration in which the liquid storage chamber is provided adjacent to the above-mentioned pressure chamber, and the pressure in the vicinity of the pressure chamber can be detected with a simple configuration by utilizing the liquid storage chamber. [Means for solving the problem]

[0007] A liquid ejection head according to a preferred aspect of the present invention comprises a nozzle substrate provided with a nozzle for ejecting liquid, a pressure chamber substrate having a pressure chamber in which pressure is applied to the liquid for ejecting the liquid from the nozzle, and an absorption chamber adjacent to the pressure chamber for absorbing vibrations of the liquid generated when pressure is applied to the liquid in the pressure chamber, a first piezoelectric element provided corresponding to the pressure chamber and applying pressure to the pressure chamber when a voltage is applied, a second piezoelectric element provided corresponding to the absorption chamber, and a pressure acquisition unit that acquires the pressure of the absorption chamber based on the voltage applied to the second piezoelectric element. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram illustrating a configuration of a liquid ejection device according to a first embodiment. [Diagram 2] FIG. 2 is a block diagram of the liquid ejection device of FIG. [Diagram 3] 2 is a cross-sectional view of a portion of the liquid ejection head shown in FIG. [Figure 4] 4 is a diagram showing a part of the pressure chamber substrate in FIG. 3. [Diagram 5] FIG. 4 is a diagram showing a part of the sealing substrate in FIG. [Figure 6] 6 is a graph showing an example of the relationship between the capacitance of a second piezoelectric body and pressure. [Figure 7] 3 is a diagram showing a second piezoelectric element and a third piezoelectric element in FIG. 2. [Figure 8] FIG. 11 is a plan view showing a second piezoelectric element of a second embodiment. [Figure 9] FIG. 11 is a plan view showing a second piezoelectric element of a third embodiment. [Figure 10] FIG. 11 is a block diagram of a liquid ejection device according to a modified example. [Figure 11] 13 is a cross-sectional view of a first piezoelectric element and a second piezoelectric element of a modified example. FIG. [Figure 12] 13 is a cross-sectional view of a first piezoelectric element and a second piezoelectric element of a modified example. FIG. [Figure 13] FIG. 11 is a cross-sectional view of a portion of a liquid ejection head according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Note that the dimensions or scale of each part in the drawings may differ from the actual dimensions, and some parts are shown diagrammatically to facilitate understanding. The scope of the present invention is not limited to these forms unless otherwise specified in the following description to the effect that the present invention is limited thereto. In addition, "element β on element α" is not limited to a configuration in which element α and element β are in direct contact with each other, but also includes a configuration in which element α and element β are not in direct contact with each other.

[0010] 1. First embodiment 1-1. Overall configuration of the liquid ejection device 100 1 is a schematic diagram illustrating the configuration of a liquid ejection device 100 according to a first embodiment. In the following, for convenience of explanation, an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other will be appropriately used. Moreover, one direction along the X-axis will be referred to as the X1 direction, and the direction opposite to the X1 direction will be referred to as the X2 direction. Similarly, one direction along the Y-axis will be referred to as the Y1 direction, and the direction opposite to the Y1 direction will be referred to as the Y2 direction. One direction along the Z-axis will be referred to as the Z1 direction, and the direction opposite to the Z1 direction will be referred to as the Z2 direction.

[0011] The liquid ejection device 100 in Fig. 1 is an inkjet printing device that ejects ink, which is an example of a liquid, onto a medium 90. The medium 90 is typically printing paper, but any printing target made of any material, such as a resin film or fabric, can be used as the medium 90. As illustrated in Fig. 1, the liquid ejection device 100 is provided with a liquid container 9 that stores ink. For example, a cartridge that can be detachably attached to the liquid ejection device 100, a bag-shaped ink pack made of a flexible film, or an ink tank that can be refilled with ink can be used as the liquid container 9.

[0012] The liquid ejection device 100 includes a control unit 20, a medium transport mechanism 22, a moving mechanism 24, and a liquid ejection head 1. The control unit 20 includes one or more processing circuits, such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array), and one or more storage circuits, such as a semiconductor memory, and performs overall control of each element of the liquid ejection device 100.

[0013] The medium transport mechanism 22 transports the medium 90 in a direction along the Y axis under the control of the control unit 20. The movement mechanism 24 reciprocates the liquid ejection head 1 along the X axis under the control of the control unit 20. The movement mechanism 24 includes a substantially box-shaped transport body 242 that houses the liquid ejection head 1, and a transport belt 244 to which the transport body 242 is fixed. Note that a configuration in which a plurality of liquid ejection heads 1 are mounted on the transport body 242, or a configuration in which the liquid container 9 is mounted on the transport body 242 together with the liquid ejection head 1, may also be employed.

[0014] The liquid ejection head 1 ejects ink supplied from a liquid container 9 from multiple nozzles onto a medium 90 under the control of a control unit 20. An image is formed on the surface of the medium 90 by each liquid ejection head 1 ejecting ink onto the medium 90 in parallel with the transport of the medium 90 by the medium transport mechanism 22 and the repeated reciprocating motion of the transport body 242.

[0015] Fig. 2 is a block diagram of the liquid ejection device 100 of Fig. 1. As shown in Fig. 2, the liquid ejection device 100 includes a control unit 20, a medium transport mechanism 22, a moving mechanism 24, and a liquid ejection head 1. The control unit 20 includes a control unit 21, a storage unit 23, and a drive signal generation circuit 25. The liquid ejection head 1 includes a drive circuit 40, a plurality of first piezoelectric elements 3, a voltage application unit 41, a pressure acquisition unit 42, one or more second piezoelectric elements 5, and one or more third piezoelectric elements 6.

[0016] The control unit 21 includes one or more processing circuits, such as a CPU or an FPGA, etc. The control unit 21 generates signals for controlling the operation of each part of the liquid ejection device 100. The control unit 21 controls the ink ejection operation of the liquid ejection head 1.

[0017] The control unit 21 generates a print signal SI, a waveform designation signal dCom, and a timing signal PTS. The print signal SI is a digital signal for designating the type of operation of the liquid ejection head 1. The print signal SI designates whether or not to supply the drive signal Com to the first piezoelectric element 3. The waveform designation signal dCom is a digital signal that defines the waveform of the drive signal Com. The drive signal Com is an analog signal for driving the first piezoelectric element 3. The timing signal PTS is a signal that defines the generation timing of the drive signal Com.

[0018] The storage unit 23 includes one or more storage circuits such as semiconductor memories. The storage unit 23 stores print data Img supplied from the host computer. The storage unit 23 stores a control program for the liquid ejection device 100.

[0019] The drive signal generating circuit 25 includes a DA conversion circuit. The drive signal generating circuit 25 generates a drive signal Com having a waveform defined by a waveform designation signal dCom. The drive signal generating circuit 25 outputs the drive signal Com every time it receives a timing signal PTS.

[0020] The drive circuit 40 switches whether or not to supply the drive signal Com to each first piezoelectric element 3 based on the print signal SI. The drive circuit 40 selects the first piezoelectric element 3 to which the drive signal Com is supplied based on the print signal SI, latch signal LAT, and change signal CH supplied from the control unit 20. The latch signal LAT defines the latch timing of the print data Img. The change signal CH defines the selection timing of the drive pulse included in the drive signal Com.

[0021] The voltage application unit 41 applies a predetermined voltage to the one or more second piezoelectric elements 5 and the one or more third piezoelectric elements 6. The voltage application unit 41 includes, for example, a power supply circuit. The pressure acquisition unit 42 acquires the pressure of an absorption chamber S2 (described below) of the liquid ejection head 1 based on the voltage applied to the second piezoelectric element 5. The pressure acquisition unit 42 includes, for example, a pressure detection element, and outputs a detection signal as a voltage value.

[0022] 1-2. Liquid ejection head 1 FIG. 3 is a cross-sectional view of a portion of the liquid ejection head 1 shown in FIG. 1, and is a cross-sectional view parallel to the XZ plane. The Z axis is an axis along the direction in which ink is ejected by the liquid ejection head 1. The direction along the Z axis is defined as the "vertical direction". The Z2 direction is an example of "one side in the vertical direction", and the Z1 direction is an example of "the other side in the vertical direction". Also, a view from a direction along the Z axis is defined as a "planar view". The Y1 direction or Y2 direction is an example of the "first direction". The X1 direction or X2 direction is an example of the "second direction".

[0023] The liquid ejection head 1 in Fig. 3 has a structure that is nearly symmetrical with respect to an imaginary plane a along the YZ plane. In the following explanation, the configuration on the right side of the imaginary plane a in Fig. 3 will be mainly explained, and the explanation of the configuration on the left side of the imaginary plane a in Fig. 3 will be omitted as appropriate.

[0024] The liquid ejection head 1 has a nozzle substrate 11, a pressure chamber substrate 12, a vibration plate 13, a sealing substrate 14, a wiring substrate 49, a first piezoelectric element 3, and a second piezoelectric element 5. The first piezoelectric element 3 includes a first piezoelectric body 31, a first electrode 32, and a second electrode 33. The second piezoelectric element 5 includes a second piezoelectric body 51, a third electrode 52, and a fourth electrode 53. Although not shown in detail, the nozzle substrate 11, the pressure chamber substrate 12, the vibration plate 13, and the sealing substrate 14 are long plates aligned along the Y axis.

[0025] The nozzle substrate 11 is a plate-like member provided with a plurality of nozzles N that eject ink, which is an example of a liquid. Each of the plurality of nozzles N is a circular through-hole that ejects ink. The plurality of nozzles N are linearly arranged along the Y axis. The nozzle substrate 11 is manufactured by processing a semiconductor substrate, such as a silicon single crystal substrate.

[0026] The pressure chamber substrate 12 is a flow path structure in which a flow path for supplying ink to each of the multiple nozzles N is formed. The pressure chamber substrate 12 is a laminate of a first substrate 121 and a second substrate 122. Each of the first substrate 121 and the second substrate 122 is manufactured by processing a semiconductor substrate such as a silicon single crystal substrate. The first substrate 121 and the second substrate 122 may be formed integrally. The pressure chamber substrate 12 may also include members other than the first substrate 121 and the second substrate 122.

[0027] Ink flow paths are formed in the pressure chamber substrate 12. Specifically, a plurality of pressure chambers S1, an absorption chamber S2, a plurality of first communication paths R1, and a second communication path R2 are formed in the pressure chamber substrate 12. Each of the first substrate 121 and the second substrate 122 has a recess or a through hole, and the recess or the through hole forms the plurality of pressure chambers S1, the absorption chamber S2, the plurality of first communication paths R1, and the second communication paths R2.

[0028] FIG. 4 is a diagram showing a part of the pressure chamber substrate 12 of FIG. 3. As shown in FIG. 4, each pressure chamber S1 has an elongated shape extending in the X2 direction. The multiple pressure chambers S1 are spaced apart from each other and lined up in the Y2 direction. Therefore, the direction in which the multiple pressure chambers S1 are lined up is the Y2 direction, which is the "first direction." Furthermore, the multiple pressure chambers S1 are provided in a one-to-one correspondence with the multiple nozzles N. Each pressure chamber S1 is a space in which pressure is applied to ink to eject ink from the nozzle N.

[0029] The multiple first communication channels R1 are spaced apart from each other and lined up in the Y2 direction. The multiple first communication channels R1 are provided in a one-to-one correspondence with the multiple pressure chambers S1. Each first communication channel R1 communicates the corresponding pressure chamber S1 with the nozzle N. Each first communication channel R1 overlaps with the corresponding pressure chamber S1 and nozzle N in a plan view.

[0030] The absorption chamber S2 is provided upstream of the pressure chambers S1. The pressure chambers S1 and the absorption chambers S2 are arranged in the X2 direction, which is the "second direction". The absorption chamber S2 has a longitudinal shape extending in the Y2 direction. The volume of the absorption chamber S2 is much larger than the volume of each pressure chamber S1. The absorption chamber S2 is provided in common to the pressure chambers S1 and is connected to the pressure chambers S1. The absorption chamber S2 is adjacent to the pressure chamber S1 and absorbs ink vibrations that occur when pressure is applied to the ink in the pressure chamber S1. The provision of the absorption chamber S2 can stabilize the ink ejection performance. In addition, since the absorption chamber S2 is adjacent to the pressure chamber S1, the efficiency of absorbing ink vibrations can be increased compared to when the absorption chambers S2 are spaced apart. Therefore, the stability of the ink ejection performance can be increased.

[0031] The second communication channel R2 is provided upstream of the absorption chamber S2 and is connected to the absorption chamber S2. The second communication channel R2 has an elongated shape extending in the Y2 direction.

[0032] As shown in Fig. 3, a vibration plate 13 is disposed on the surface in the Z2 direction of the pressure chamber substrate 12. The thickness of the vibration plate 13 is much thinner than the thicknesses of the first substrate 121 and the second substrate 122 of the pressure chamber substrate 12. The thickness is the length in the Z1 direction. The vibration plate 13 is elastically deformable. The vibration plate 13 includes a plurality of first vibration plates 131 and second vibration plates 132. The plurality of first vibration plates 131 and second vibration plates 132 are formed from a single member.

[0033] The multiple first vibration plates 131 are provided in a one-to-one correspondence with the multiple pressure chambers S1. Each of the first vibration plates 131 is a portion of the vibration plate 13 that overlaps with the multiple pressure chambers S1 in a plan view. Each of the first vibration plates 131 forms a part of the pressure chamber S1. When a voltage is applied to the first piezoelectric body 31 of the first piezoelectric element 3, the first vibration plate 131 vibrates and applies pressure to the pressure chamber S1. By providing the first vibration plate 131, the first piezoelectric element 3 can be provided above the pressure chamber S1, and pressure due to vibration caused by application of a voltage to the first piezoelectric body 31 via the first vibration plate 131 can be efficiently applied to the pressure chamber S1.

[0034] The second vibration plate 132 is a portion of the vibration plate 13 that overlaps with the absorption chamber S2 in a plan view. The second vibration plate 132 forms a part of the absorption chamber S2. The second vibration plate 132 is driven by pressure applied from the absorption chamber S2, and applies pressure to the second piezoelectric body 51 of the second piezoelectric element 5. By providing the second vibration plate 132, the second piezoelectric element 5 can be provided above the absorption chamber S2, and pressure can be applied to the second piezoelectric body 51 efficiently.

[0035] Furthermore, the multiple first diaphragms 131 and the multiple second diaphragms 132 are not separated, but are formed from a continuous member. This makes it easy to arrange the first diaphragms 131 and the second diaphragms 132 adjacent to each other. This also makes it easy to arrange the multiple pressure chambers S1 and the absorption chambers S2 adjacent to each other. Because the multiple pressure chambers S1 and the absorption chambers S2 can be arranged adjacent to each other, the efficiency of absorbing ink vibrations can be improved.

[0036] The diaphragm 13 is manufactured by processing a semiconductor substrate such as a silicon single crystal substrate. The diaphragm 13 may be formed by a part of the pressure chamber substrate 12. For example, the diaphragm 13 may be formed by thinning a part of the second substrate 122.

[0037] A sealing substrate 14 is disposed on the surface in the Z2 direction of the vibration plate 13. The sealing substrate 14 is a structure that protects a plurality of first piezoelectric elements 3 and a plurality of second piezoelectric elements 5, which will be described later, and reinforces the mechanical strength of the pressure chamber substrate 12.

[0038] The sealing substrate 14 is formed with a third communication flow path R3, a first space H1, a second space H2, and a space for wiring H0. The sealing substrate 14 has a recess or a through hole, and each of the flow paths or spaces is formed by the recess or the through hole. The third communication flow path R3 and the space for wiring H0 are holes penetrating the sealing substrate 14. The first space H1 and the second space H2 are spaces surrounded by recesses formed in the sealing substrate 14.

[0039] The third communication flow path R3 overlaps with the second communication flow path R2 in plan view and is connected to the second communication flow path R2. The third communication flow path R3 and the second communication flow path R2 form a common ink chamber R. The common ink chamber R functions as a reservoir. A filter 141 is provided in the portion overlapping with the common ink chamber R in plan view to remove air bubbles and foreign matter that may get mixed in with the ink. The filter 141 may be omitted.

[0040] Fig. 5 is a plan view showing a part of the sealing substrate 14 of Fig. 3. For convenience, the second electrode 33 of the first piezoelectric element 3 and the third electrode 52 of the second piezoelectric element 5 are indicated by dots in Fig. 5.

[0041] 5, the first space H1, the second space H2, the third communication channel R3, and the wiring space H0 each have a longitudinal shape extending in the Y2 direction. The wiring space H0, the first space H1, the second space H2, and the third communication channel R3 are arranged in this order in the X2 direction.

[0042] 3, a plurality of first piezoelectric elements 3 are arranged in the first space H1. A second piezoelectric element 5 is arranged in the second space H2. A wiring board 49 is arranged in the wiring space H0. The wiring board 49 is joined to the pressure chamber substrate 12. The wiring board 49 is a mounting component on which a plurality of wirings are formed for electrically connecting the control unit 20 and the liquid ejection head 1. For example, a TCP (Tape Carrier Package) or an FPC (Flexible Printed Circuit) is used as the wiring board 49.

[0043] Each of the first piezoelectric elements 3 has an elongated shape extending in the X2 direction. The multiple first piezoelectric elements 3 are spaced apart from each other and lined up in the Y2 direction. The multiple first piezoelectric elements 3 are provided in a one-to-one correspondence with the multiple pressure chambers S1. The second piezoelectric element 5 has an elongated shape extending in the Y2 direction and extends in a direction intersecting with the multiple first piezoelectric elements 3. The second piezoelectric element 5 is provided corresponding to the absorption chamber S2 and overlaps with the absorption chamber S2 in a plan view.

[0044] The first piezoelectric element 3 is provided corresponding to the pressure chamber S1. Specifically, the first piezoelectric element 3 is arranged for each pressure chamber S1 on the surface of the first vibration plate 131 opposite to the pressure chamber S1. The first piezoelectric element 3 is an energy generating element that generates energy for ejecting ink when a drive signal Com is applied to it. The first piezoelectric element 3 is also a driving element that is driven when the drive signal Com is applied to it. The first piezoelectric element 3 contracts when a voltage is applied to it, bending the first vibration plate 131 and pressurizing the pressure chamber S1.

[0045] The first piezoelectric element 3 generally includes a second electrode 33, a first piezoelectric body 31, and a first electrode 32. The second electrode 33, the first piezoelectric body 31, and the first electrode 32 are stacked in this order from the first vibration plate 131. Therefore, the first electrode 32 is located in the Z2 direction, which is the "upward direction" of the "one side in the vertical direction" from the first piezoelectric body 31. The second electrode 33 is located in the Z1 direction, which is the "downward direction" of the "other side in the vertical direction" from the first piezoelectric body 31. By providing the first electrode 32 and the second electrode 33, pressure is efficiently applied to the first piezoelectric body 31. The second electrode 33 and the first vibration plate 131 may be in contact with each other, or another member may be interposed between the second electrode 33 and the first vibration plate 131.

[0046] The first piezoelectric body 31 is a dielectric body provided for each of the first piezoelectric elements 3. The first piezoelectric bodies 31 may be connected to each other. For example, the first piezoelectric bodies 31 may be separated by forming a plurality of notches in a strip-shaped dielectric film extending along the Y2 direction. Therefore, the first piezoelectric bodies 31 may be formed of a single dielectric film. The first piezoelectric body 31 is formed of a known piezoelectric material, such as lead zirconate titanate (Pb(Zr,Ti)O3).

[0047] The first electrode 32 is a common electrode provided in common to the multiple first piezoelectric bodies 31. The first electrode 32 is in the shape of a strip extending in the Y2 direction so as to be continuous across the multiple first piezoelectric elements 3. The second electrode 33 is provided in common to the multiple pressure chambers S1. By providing the electrodes in common, it is easier to miniaturize the first piezoelectric elements 3 compared to when they are individual. Like the second electrode 33, the first electrode 32 is formed of a low-resistance conductive material such as platinum (Pt) or iridium (Ir).

[0048] As shown in FIG. 5, the second electrode 33 is elongated along the X-axis. The multiple second electrodes 33 are arranged along the Y-axis. The second electrodes 33 are individual electrodes formed at a distance from each other for each first piezoelectric element 3. The second electrodes 33 are provided individually for the multiple pressure chambers S1. By providing the second electrodes individually, even if the multiple first piezoelectric bodies 31 are formed of a single dielectric film, the single dielectric film can be divided into the multiple first piezoelectric bodies 31. The second electrodes 33 are formed of a conductive material such as platinum or iridium.

[0049] The first piezoelectric element 3 is a piezoelectric element involved in the ejection of ink. A reference voltage, which is a constant voltage, is applied to the first electrode 32. The reference voltage may be, for example, a ground voltage or a voltage higher than the ground voltage. A drive signal Com is supplied to the second electrode 33. Thus, a drive voltage, the voltage of which changes with time, is applied to the second electrode 33.

[0050] A voltage corresponding to the difference between the reference voltage applied to the first electrode 32 and the drive voltage supplied to the second electrode 33 is applied to the first piezoelectric body 31. Therefore, the drive circuit 40 of FIG. 2 applies a drive voltage whose voltage changes with time to the first piezoelectric body 31. When a voltage corresponding to the difference between the reference voltage applied to the first electrode 32 and the drive voltage supplied to the second electrode 33 is applied to the first piezoelectric body 31, the first piezoelectric body 31 is deformed, and the first piezoelectric element 3 generates energy that causes the first vibration plate 131 to bend. Therefore, the first piezoelectric element 3 applies pressure to the pressure chamber S1 when the voltage is applied. The first vibration plate 131 is bent and deformed by the energy generated by the first piezoelectric element 3, so that the pressure in the pressure chamber S1 changes, and the ink in the pressure chamber S1 is ejected from the nozzle N shown in FIG. 3.

[0051] The second piezoelectric element 5 shown in Fig. 3 is provided corresponding to the absorption chamber S2. Specifically, the second piezoelectric element 5 is disposed on the surface of the first vibration plate 131 opposite to the absorption chamber S2. The second piezoelectric element 5 is used to detect the pressure in the absorption chamber S2. The second piezoelectric element 5 deforms in response to the second vibration plate 132 that bends in response to the pressure in the absorption chamber S2.

[0052] The second piezoelectric element 5 has a fourth electrode 53, a second piezoelectric body 51, and a third electrode 52. The fourth electrode 53, the second piezoelectric body 51, and the third electrode 52 are laminated in this order from the second diaphragm 132. The fourth electrode 53 and the second diaphragm 132 may be in contact with each other, or another member may be interposed between the fourth electrode 53 and the second diaphragm 132.

[0053] The second piezoelectric body 51 is a strip-shaped dielectric film extending in the Y2 direction. The second piezoelectric body 51 is made of a known piezoelectric material such as lead zirconate titanate. The thickness of the second piezoelectric body 51 is the same as that of the first piezoelectric body 31. The thickness is the length in the Z1 direction. The third electrode 52 and the fourth electrode 53 are each elongated along the Y axis. The third electrode 52 and the fourth electrode 53 are each made of a conductive material such as platinum or iridium.

[0054] 5, the fourth electrode 53 is illustrated, but the planar areas of the third electrode 52 and the second piezoelectric body 51 are almost the same as the planar area of ​​the fourth electrode 53, and the third electrode 52 and the second piezoelectric body 51 overlap the fourth electrode 53 in a planar view. Moreover, the second piezoelectric body 51, the third electrode 52, and the fourth electrode 53 overlap almost the entire area of ​​the absorption chamber S2 in a planar view.

[0055] As described above, in the liquid ejection head 1 of this embodiment, the pressure chamber S1 and the absorption chamber S2 are provided in the pressure chamber substrate 12, and the pressure chamber S1 and the absorption chamber S2 are adjacent to each other. In this embodiment in which the pressure chamber S1 and the absorption chamber S2 are adjacent to each other, a second piezoelectric body 51 is provided corresponding to the absorption chamber S2. The liquid ejection head 1 is further provided with a pressure acquisition unit 42 that acquires the pressure of the absorption chamber S2 based on the voltage applied to the second piezoelectric body 51.

[0056] As described above, the absorption chamber S2 is a space that absorbs the vibration of the ink that occurs when pressure is applied to the ink in the pressure chamber S1. By providing the absorption chamber S2, the ink ejection performance can be stabilized. In this embodiment, the second piezoelectric body 51 is provided corresponding to the absorption chamber S2, and the pressure of the absorption chamber S2 can be detected based on the voltage applied to the second piezoelectric body 51. Therefore, the pressure in the vicinity of the pressure chamber S1 can be detected using the absorption chamber S2. Therefore, the pressure in the vicinity of the pressure chamber S1 can be detected with a simple configuration without forming a separate space for detecting the pressure in the vicinity of the pressure chamber S1. By being able to obtain the pressure of the absorption chamber S2 in the vicinity of the pressure chamber S1, the behavior of the ink according to the pressure of the pressure chamber S1 can be detected. Therefore, for example, it can be detected whether or not various malfunctions such as insufficient supply of ink to the multiple pressure chambers S1 and the absorption chamber S2 occur. Therefore, by being able to obtain the pressure of the absorption chamber S2 in the vicinity of the pressure chamber S1, it can contribute to improving the quality of the liquid ejection head 1.

[0057] Also, unlike the pressure chamber S1, the absorption chamber S2 is not directly related to the ejection of ink. Therefore, it is always possible to detect the pressure in the absorption chamber S2 based on the voltage applied to the second piezoelectric body 51, regardless of the ejection of ink.

[0058] In this embodiment, the capacitance C2 is obtained based on the voltage applied to the second piezoelectric body 51, and the pressure in the absorption chamber S2 is detected based on the capacitance C2.

[0059] The capacitance C2 changes according to the pressure in the absorption chamber S2. Specifically, when the pressure in the absorption chamber S2 changes, the second vibration plate 132 deforms according to the change in pressure. The second vibration plate 132 deforms so as to bend in the Z1 direction or the Z2 direction. When the second vibration plate 132 deforms, stress is applied to the second piezoelectric body 51 on the second vibration plate 132. The stress applied to the second piezoelectric body 51 changes the polarization state of the second piezoelectric body 51. This change in the polarization state appears as a change in the dielectric constant ε of the second piezoelectric body 51, causing a change in the capacitance C. Therefore, the capacitance C changes according to the change in pressure in the absorption chamber S2.

[0060] The capacitance C is expressed by equation [1]. C=ε(S / d) …[1] S is the electrode area, and d is the distance between the third electrode 52 and the fourth electrode 53.

[0061] Fig. 6 is a graph showing an example of the relationship between the capacitance C2 of the second piezoelectric body 51 and the pressure P. The horizontal axis of Fig. 6 is the pressure P [kPa], and the vertical axis is the capacitance C2 [nF]. In the example shown in Fig. 6, as the pressure P increases, the capacitance C of the second piezoelectric body 51 decreases.

[0062] As shown in Fig. 6, since there is a correlation between the capacitance C2 of the second piezoelectric body 51 and the pressure P, the pressure in the absorption chamber S2 can be detected based on the capacitance C2 by using the second piezoelectric body 51. The pressure acquisition unit 42 in Fig. 2 described above acquires the capacitance C2 of the second piezoelectric body 51 based on the voltage applied to the second piezoelectric body 51, and acquires the pressure in the absorption chamber S2 based on the capacitance C2. By providing the second piezoelectric body 51 and the pressure acquisition unit 42, the pressure in the absorption chamber S2 can be detected based on the capacitance C2, making it possible to detect minute changes in pressure.

[0063] 7 is a diagram showing the second piezoelectric element 5 and the third piezoelectric element 6 of FIG. 2. The third piezoelectric element 6 shown in FIG. 7 is a reference piezoelectric element. The third piezoelectric element 6 is connected in series to the second piezoelectric element 5. The third piezoelectric element 6 is not disposed on the above-mentioned vibration plate 13, but is provided in a location that is not deformed by the pressure in the flow path.

[0064] The third piezoelectric element 6 has the same configuration as the second piezoelectric element 5. The third piezoelectric element 6 includes a third piezoelectric body 61, a fifth electrode 62, and a sixth electrode 63. The third piezoelectric body 61 is sandwiched between the fifth electrode 62 and the sixth electrode 63. The third piezoelectric body 61 is a dielectric material, and is formed of a known piezoelectric material such as lead zirconate titanate. The capacitance of the third piezoelectric body 61 is known.

[0065] Each of the fifth electrode 62 and the sixth electrode 63 is formed of a conductive material such as platinum or iridium. The fifth electrode 62 is electrically connected to the fourth electrode 53 of the second piezoelectric element 5. A constant predetermined voltage is applied to the sixth electrode 63. In the illustrated example, the predetermined voltage is a ground voltage, and the sixth electrode 63 is grounded. In addition, a constant predetermined voltage Vx different from the voltage applied to the sixth electrode 63 is applied to the third electrode 52 of the second piezoelectric element 5 described above. Therefore, the voltage application unit 41 in FIG. 2 applies the predetermined voltage Vx to the second piezoelectric body 51 and the third piezoelectric body 61.

[0066] Based on the voltage V2 applied to the second piezoelectric body 51, the voltage V3 applied to the third piezoelectric body 61, and the capacitance C3 of the third piezoelectric body 61, the capacitance C2 of the second piezoelectric body 51 can be obtained as shown in [4] below.

[0067] V2 = C2 × Q2 …[2] V3 = C3 × Q3 …[3] C2 = (V2 / V3) × C3 …[4] Equation [4] is derived from equation [2] and equation [3]. Q2 is the charge generated in the second piezoelectric element 5, and Q3 is the charge generated in the third piezoelectric element 6. Voltage V2 is the voltage applied to the second piezoelectric body 51 when a predetermined voltage Vx is applied by the voltage application unit 41. Voltage V3 is the voltage applied to the third piezoelectric body 61 when a predetermined voltage Vx is applied by the voltage application unit 41.

[0068] When stress is applied to the second piezoelectric body 51 and the capacitance C2 of the second piezoelectric body 51 changes, the voltage V2 applied to the second piezoelectric body 51 changes. The signal of this voltage V2 is acquired by the pressure acquisition unit 42 in FIG. 2. The capacitance C2 of the second piezoelectric body 51 is calculated by equation [4] using the voltages V2 and V3 and the known capacitance C3. Therefore, the pressure acquisition unit 42 acquires the capacitance C2 based on the voltages V2 and V3 and the capacitance C3. Then, the pressure P of the second piezoelectric body 51 is calculated from the capacitance C2 and the correlation between the capacitance C2 and the pressure P shown in FIG. 6. In this way, the pressure acquisition unit 42 acquires the pressure in the absorption chamber S2 based on the capacitance C2.

[0069] In this embodiment, as described above, the pressure acquisition unit 42 obtains the capacitance C2 of the second piezoelectric body 51 using the third piezoelectric body 61, whose capacitance C3 is known, and detects the pressure in the absorption chamber S2 using the capacitance C2. According to the detection method using the third piezoelectric body 61, it is possible to detect the pressure in the absorption chamber S2 near the pressure chamber S1 with a simple configuration. Note that the method of detecting the pressure in the absorption chamber S2 is not limited to the detection method using the third piezoelectric body 61, and the third piezoelectric element 6 may be omitted depending on the detection method.

[0070] As described above, the pressure chamber substrate 12 is provided with at least a plurality of pressure chambers S1 and one absorption chamber S2 commonly connected to the plurality of pressure chambers S1. Since the volume of the absorption chamber S2 is larger than the volume of each pressure chamber S1, the plane area of ​​the second vibration plate 132 forming the absorption chamber S2 can be made larger than the plane area of ​​each first vibration plate 131 forming each pressure chamber S1. Therefore, the displacement of the second vibration plate 132 can be made larger than the displacement of the first vibration plate 131. Therefore, the absorption efficiency of the absorption chamber S2 can be improved. Furthermore, by detecting the pressure of one absorption chamber S2 commonly connected to the plurality of pressure chambers S1, the pressure of the absorption chamber S2 due to the influence of the plurality of pressure chambers S1 can be detected, instead of the pressure of each pressure chamber S1. Therefore, the pressure can be used to detect malfunctions such as whether or not various malfunctions such as a shortage of ink supply have occurred.

[0071] 5, the second electrode 33 extends in the X2 direction. The fourth electrode 53 extends in the Y2 direction. The Y2 direction, which is the "first direction," is the direction in which the multiple pressure chambers are aligned. The X2 direction, which is the "second direction," is the direction in which the pressure chambers S1 and the absorption chambers S2 are aligned.

[0072] The first piezoelectric body 31 and the second piezoelectric body 51 have different directions in which they tend to bend. The pressure chamber S1, the first piezoelectric body 31, and the second electrode 33 are elongated along the X2 direction. When the pressure chamber S1 extends in the X2 direction and the excluded volume is to be made as large as possible, the first piezoelectric body 31 and the second electrode 33 also tend to extend in the X2 direction. Therefore, each of the first piezoelectric body 31 and the second electrode 33 tends to bend around the center in the X2 direction. Therefore, by providing the first piezoelectric body 31 along the extension direction of the pressure chamber S1, the ejection accuracy can be improved.

[0073] On the other hand, the absorption chamber S2, the second piezoelectric body 51, and the fourth electrode 53 are elongated along the Y2 direction. Therefore, each of the second piezoelectric body 51 and the fourth electrode 53 is easily deflected around the center in the Y2 direction. In addition, the absorption chamber S2 is provided in common with respect to the multiple pressure chambers S1, and pressure is commonly applied to the absorption chamber S2 from the multiple pressure chambers S1. It is difficult to imagine that pressure is applied in a concentrated manner only from a specific pressure chamber S1. From this perspective, each of the second piezoelectric body 51 and the fourth electrode 53 is easily deflected around the center in the Y2 direction. Therefore, by providing the second piezoelectric body 51 along the extension direction of the absorption chamber S2, the pressure detection sensitivity can be improved.

[0074] For example, the second piezoelectric body 51 and the fourth electrode 53 may be arranged along the X2 direction. In this case, however, the amount of deflection of the second piezoelectric body 51 and the fourth electrode 53 will be smaller than the amount of deflection when the second piezoelectric body 51 and the fourth electrode 53 are arranged along the X2 direction.

[0075] As shown in FIG. 5, the fourth electrode 53 overlaps the center of the absorption chamber S2 in the X2 direction. Similarly, the second piezoelectric body 51 overlaps the center of the absorption chamber S2 in the X2 direction. Therefore, the fourth electrode 53 and the second piezoelectric body 51 overlap the center of the second vibration plate 132 in the X2 direction. The center of the second vibration plate 132 in the X2 direction is the part that is most displaced. Therefore, by overlapping the fourth electrode 53 and the second piezoelectric body 51 with the center of the absorption chamber S2 in the X2 direction, the detection accuracy of the pressure of the absorption chamber S2 can be improved. Note that the fourth electrode 53 and the second piezoelectric body 51 do not have to overlap with the center in the X2 direction.

[0076] According to the present embodiment described above, the pressure in the vicinity of the pressure chamber S1 can be obtained by utilizing the absorption chamber S2, which is a space that absorbs vibrations of the ink.

[0077] 2. Second embodiment A second embodiment will be described. In the following exemplary embodiment, for elements having the same actions and functions as those in the first embodiment, the reference numerals used in the description of the first embodiment will be used and detailed descriptions of each will be omitted as appropriate.

[0078] Fig. 8 is a plan view showing a second piezoelectric element 5A of the second embodiment. The second piezoelectric element 5A shown in Fig. 8 does not overlap the entire area of ​​the absorption chamber S2 in a plan view. Therefore, the second piezoelectric body 51 of the second piezoelectric element 5A is not provided in the entire area of ​​the absorption chamber S2 in a plan view. For example, the length of the second piezoelectric body 51 in the X2 direction is half or less of the length of the absorption chamber S2 and the second vibration plate 132 in the X2 direction.

[0079] Since the second piezoelectric body 51 is not provided over the entire area of ​​the absorption chamber S2 in a plan view, the second diaphragm 132 is more easily deformed than when the second piezoelectric body 51 is provided over the entire area. By providing the second piezoelectric body 51 overlapping the center of the second diaphragm 132 in the X2 direction, which is the part most likely to be deformed, the detection accuracy of the pressure in the absorption chamber S2 can be improved.

[0080] 3. Third embodiment A third embodiment will be described. In the following exemplary embodiment, for elements having the same actions and functions as those in the first embodiment, the reference numerals used in the description of the first embodiment will be used and detailed descriptions of each will be omitted as appropriate.

[0081] Fig. 9 is a plan view showing a second piezoelectric element 5B according to the third embodiment. The second piezoelectric element 5B shown in Fig. 9 has a bellows shape that extends along the X2 direction and is folded back sequentially in the Y2 direction.

[0082] The second piezoelectric element 5 includes a plurality of first portions 501 and a plurality of second portions 502. The plurality of first portions 501 are portions extending in the X2 direction, spaced apart from each other and arranged in the Y2 direction. The plurality of second portions 502 are portions extending in the Y2 direction. Each second portion 502 is disposed between two adjacent first portions 501 and connects the two adjacent first portions 501. The plurality of second portions 502 are disposed alternately at the ends of the first portions 501 in the X1 direction and the ends of the first portions 501 in the X2 direction. The second portions 502 located furthest in the Y1 direction among the plurality of second portions 502 are counted in the Y2 direction, with the second portions 502 being numbered 1. In this case, for example, the odd-numbered second portions 502 among the plurality of second portions 502 are connected to the ends of the first portions 501 in the X2 direction. The even-numbered second portions 502 among the plurality of second portions 502 are connected to the ends of the first portions 501 in the X1 direction.

[0083] The length of one first portion 501 is longer than the length of one second portion 502. As a result, the first portion 501 bends alternately in the X1 direction and the X2 direction, while the second portion 502 shifts little by little along the Y2 direction, resulting in a shape that extends along the Y2 direction as a whole. This shape is referred to as a shape that "extends along the X2 direction and is folded back sequentially."

[0084] The second piezoelectric body 51, the third electrode 52 and the fourth electrode 53 of the second piezoelectric element 5B are configured to have a bellows shape that extends along the X2 direction and turns back in sequence. Since the second piezoelectric element 5B has a bellows shape, the second piezoelectric element 5B is more susceptible to stress due to the deformation of the second vibration plate 132 than the second piezoelectric element 5 of the first embodiment, which is elongated along the Y2 direction. Also, since the second piezoelectric element 5B has a bellows shape, the plane area is reduced compared to the second piezoelectric element 5 of the first embodiment. Therefore, the volume of the second piezoelectric element 5 on the second vibration plate 132 is reduced. Therefore, the second vibration plate 132 is more likely to deform. This improves the detection accuracy of the pressure in the absorption chamber S2.

[0085] The shape of the second piezoelectric element 5 is preferably a shape that is easily subjected to stress due to deformation of the second diaphragm 132, and is not limited to the bellows shape shown in the figure.

[0086] 4. Variations The above-described embodiment may be modified in various ways. Specific modified aspects that may be applied to the above-described embodiment are illustrated below. Two or more aspects selected from the following examples may be combined as appropriate to the extent that they are not mutually contradictory.

[0087] 10 is a block diagram of a liquid ejection device 100a according to a modified example. The liquid ejection device 100a includes a liquid ejection head 1a and a control unit 20a. A drive circuit 40, a voltage application unit 41, and a pressure acquisition unit 42 are provided in the control unit 20a. The liquid ejection head 1a is not provided with the voltage application unit 41 or the pressure acquisition unit 42.

[0088] 11, the drive circuit 40, the voltage application unit 41, and the pressure acquisition unit 42 may be provided in part or in whole in the control unit 20. With this liquid ejection device 100a, as in each of the embodiments, the pressure in the vicinity of the pressure chamber S1 can be acquired by utilizing the absorption chamber S2, which is a space that absorbs vibrations of the ink.

[0089] 11 and 12 are cross-sectional views of modified examples of the first piezoelectric element 3 and the second piezoelectric element 5. A thickness D5 of the second piezoelectric body 51 of the second piezoelectric element 5 may be different from a thickness D3 of the first piezoelectric body 31 of the first piezoelectric element 3.

[0090] For example, in FIG. 11, the thickness D5 of the second piezoelectric body 51 is thinner than the thickness D3 of the first piezoelectric body 31. By making the thickness thinner, the second piezoelectric body 51 is easier to deform than the first piezoelectric body 31. The first piezoelectric body 31 acts actively, whereas the second piezoelectric body 51 acts passively. Therefore, by making the thickness D5 thinner than the thickness D3, it is possible to improve the detection accuracy of the pressure in the absorption chamber S2 compared to when the thickness D5 is thicker. On the other hand, the first piezoelectric body 31 is a part that contributes to ejection. Therefore, by making the thickness D3 thicker than the thickness D5, it is possible to reduce cracks and the like.

[0091] 12, for example, the thickness D5 of the second piezoelectric body 51 is thicker than the thickness D3 of the first piezoelectric body 31. When the thickness D5 is thicker than the thickness D3, that is, when the thickness D3 is thinner than the thickness D5, the first piezoelectric body 31 is easier to deform than the second piezoelectric body 51. This can improve the ink ejection performance.

[0092] Furthermore, the "liquid ejection head" may be a circulation type head having a so-called circulation flow path.

[0093] Fig. 13 is a cross-sectional view of a portion of a modified liquid ejection head 10. The liquid ejection head 10 shown in Fig. 13 has a nozzle substrate 11, a pressure chamber substrate 120, a vibration plate 130, a sealing substrate 140, a case 150, a wiring substrate 49, a first piezoelectric element 3, a second piezoelectric element 4, and a fourth piezoelectric element 7. The liquid ejection head 10 in Fig. 13 is a circulation type head having a so-called circulation flow path.

[0094] The pressure chamber substrate 120 is a laminate of a third substrate 124 and a fourth substrate 125. These substrates are manufactured by processing a semiconductor substrate such as a silicon single crystal substrate. In addition to a plurality of pressure chambers S1, an absorption chamber S2, a plurality of first communication channels R1 and a second communication channel R2, a plurality of fourth communication channels R4, a plurality of fifth communication channels R5, a sixth communication channel R6, and a discharge-side absorption chamber S3 are formed in the pressure chamber substrate 120. The absorption chamber S2 is a supply-side absorption chamber.

[0095] One first communication channel R1 communicates with one fifth communication channel R5 via one fourth communication channel R4. Each fourth communication channel R4 overlaps with a nozzle N in a plan view. Each fifth communication channel R5 communicates with a discharge-side absorption chamber S3. The discharge-side absorption chamber S3 overlaps with the fourth piezoelectric element 7 in a plan view. The discharge-side absorption chambers S3 communicate with a sixth communication channel R6.

[0096] The diaphragm 130 includes a third diaphragm 133 in addition to a plurality of first diaphragms 131 and second diaphragms 132. The third diaphragm 133 is a portion of the diaphragm 130 that overlaps with the discharge-side absorption chamber S3 in a plan view.

[0097] The case 150 is in contact with the sealing substrate 140. The case 150 and the sealing substrate 140 may be integrated. A third communication flow path R3 and a seventh communication flow path R7 are formed in the case 150. The seventh communication flow path R7 and the sixth communication flow path R6 form a common ink chamber R0.

[0098] In addition to the first space H1, the second space H2, and the wiring space H0, a third space H3 is formed in the sealing substrate 140. A fourth piezoelectric element 7 is disposed in the third space H3. The fourth piezoelectric element 7 is disposed on the surface of the third diaphragm 133 opposite to the discharge-side absorption chamber S3. The fourth piezoelectric element 7 is used to detect the pressure in the discharge-side absorption chamber S3. The fourth piezoelectric element 7 deforms in response to the third diaphragm 133 deflecting in response to the pressure in the discharge-side absorption chamber S3.

[0099] The fourth piezoelectric element 7 has a seventh electrode 72, a third piezoelectric body 71, and an eighth electrode 73. These are elongated along the Y axis. The eighth electrode 73, the third piezoelectric body 71, and the seventh electrode 72 are laminated in this order from the third vibration plate 133. The third piezoelectric body 71 is made of a known piezoelectric material such as lead zirconate titanate. The seventh electrode 72 and the eighth electrode 73 are each made of a conductive material such as platinum or iridium. The fourth piezoelectric element 7 does not apply pressure to the liquid in the flow path, but serves to absorb vibrations.

[0100] The third diaphragm 133, the fourth piezoelectric element 7, and the discharge-side absorption chamber S3 are elongated along the Y-axis and are provided for the multiple pressure chambers S1, but may be provided for each pressure chamber S1. Therefore, multiple third diaphragms 133, fourth piezoelectric elements 7, and discharge-side absorption chambers S3 may be provided.

[0101] In this liquid ejection head 10, ink flows through the common ink chamber R and the absorption chamber S2 into the pressure chamber S1. When the first piezoelectric element 3 is driven, the pressure in the pressure chamber S1 fluctuates, and this pressure fluctuation causes the ink to be ejected as ink droplets from the nozzle N through the first communication channel R1 and the fourth communication channel R4. At the same time, the ink flows back through the fifth communication channel R5, the discharge side absorption chamber S3, and the common ink chamber R0. In this manner, the ink circulates.

[0102] Furthermore, in the liquid ejection head 10, an absorption chamber S2 is provided in the X2 direction relative to the pressure chamber S1, and a discharge-side absorption chamber S3 is provided in the X1 direction relative to the pressure chamber S1. In other words, vibration absorbing mechanisms are provided on the ink supply side and discharge side relative to the pressure chamber S1. Furthermore, the distance between the absorption chamber S2 and the pressure chamber S1 is shorter than the distance between the discharge-side absorption chamber S3 and the pressure chamber S1. By detecting the pressure in the vicinity of the pressure chamber S1 using the absorption chamber S2, which is closer to the pressure chamber S1, the behavior of the ink in response to the pressure of the pressure chamber S1 can be detected with greater accuracy.

[0103] The "liquid ejection device" can be used in various devices such as facsimile machines and copy machines, as well as devices dedicated to printing. The uses of the liquid ejection device are not limited to printing. For example, a liquid ejection device that ejects a solution of a color material is used as a manufacturing device for forming a color filter of a display device such as a liquid crystal display panel. A liquid ejection device that ejects a solution of a conductive material is used as a manufacturing device for forming wiring and electrodes of a wiring board. A liquid ejection device that ejects a solution of an organic substance related to a living body is used as a manufacturing device for manufacturing a biochip, for example.

[0104] Although the present invention has been described based on the preferred embodiment, the present invention is not limited to the above embodiment. Furthermore, the configuration of each part of the present invention can be replaced with any configuration that exhibits the same function as the above embodiment, and any configuration can be added. [Explanation of symbols]

[0105] 1...liquid ejection head, 1a...liquid ejection head, 3...first piezoelectric element, 5...second piezoelectric element, 5A...second piezoelectric element, 5B...second piezoelectric element, 6...third piezoelectric element, 9...liquid container, 11...nozzle substrate, 12...pressure chamber substrate, 13...diaphragm, 14...sealing substrate, 20...control unit, 21...control section, 22...medium conveying mechanism, 23...storage section, 24...movement mechanism, 25...driving signal generating circuit, 31...first piezoelectric body, 32...first electrode, 33...second electrode, 40...driving circuit, 41...voltage application section, 42...pressure acquisition section, 49...wiring substrate, 51...second piezoelectric body, 52...third electrode, 53...fourth electrode, 61...third piezoelectric body, 62...fifth electrode, 63...sixth electrode, 90...medium, 100...liquid ejection device, 100a...liquid ejection device, 121...first substrate, 122...second substrate, 131...first diaphragm, 132...second diaphragm, 141...filter, 242...transport body, 244...transport belt, 501...first portion, 502...second portion, D3...thickness, D5...thickness, H0...wiring space, H1...first space, H2...second space, N...nozzle, P...pressure, R...common ink chamber, R1...first communicating flow path, R2...second communicating flow path, R3...third communicating flow path, S1...pressure chamber, S2...absorption chamber, V2...voltage, V3...voltage, Vx...predetermined voltage, a...virtual surface.

Claims

1. a nozzle substrate provided with nozzles for ejecting liquid; a pressure chamber substrate having a pressure chamber in which pressure is applied to the liquid for ejecting the liquid from the nozzle, and an absorption chamber adjacent to the pressure chamber, which absorbs vibrations of the liquid generated when pressure is applied to the liquid in the pressure chamber; a first piezoelectric body provided corresponding to the pressure chamber and applying pressure to the pressure chamber when a voltage is applied thereto; A second piezoelectric body provided in correspondence with the absorption chamber; a pressure acquisition section that acquires a pressure in the absorption chamber based on a voltage applied to the second piezoelectric body.

2. The liquid ejection head according to claim 1 , wherein the pressure acquisition unit acquires the capacitance of the second piezoelectric element based on the voltage applied to the second piezoelectric element, and acquires the pressure in the absorption chamber based on the capacitance.

3. a third piezoelectric element having a known capacitance, the third piezoelectric element being connected in series with the second piezoelectric element; a voltage application unit that applies a predetermined voltage to the second piezoelectric body and the third piezoelectric body, The liquid ejection head according to claim 2, characterized in that the pressure acquisition unit acquires the capacitance of the second piezoelectric body based on the voltage applied to the second piezoelectric body when the specified voltage is applied by the voltage application unit, the voltage applied to the third piezoelectric body when the specified voltage is applied by the voltage application unit, and the capacitance of the third piezoelectric body, and acquires the pressure of the absorption chamber based on the capacitance.

4. 3. The liquid ejection head according to claim 2, further comprising a drive circuit for applying to the first piezoelectric element a drive voltage that changes with time.

5. 2. The liquid ejection head according to claim 1, wherein the thickness of the second piezoelectric element is different from the thickness of the first piezoelectric element.

6. 2. The liquid ejection head according to claim 1, wherein the pressure chamber substrate is provided with at least a plurality of the pressure chambers and one of the absorption chambers connected in common to the plurality of pressure chambers.

7. a first diaphragm that vibrates when a voltage is applied to the first piezoelectric body to apply pressure to the pressure chamber; 7. The liquid ejection head according to claim 6, further comprising a second vibration plate that is driven by pressure applied from the absorption chamber to apply pressure to the second piezoelectric element.

8. 8. The liquid ejection head according to claim 7, wherein the first diaphragm and the second diaphragm are not separate but are formed of a continuous member.

9. a first electrode provided in common to the plurality of pressure chambers and positioned on one side of the first piezoelectric body in the up-down direction; a second electrode provided for each of the pressure chambers and positioned on the other side of the first piezoelectric body in the up-down direction; a third electrode provided for the absorption chamber and positioned on the one side in the up-down direction of the second piezoelectric body; 8. The liquid ejection head according to claim 7, further comprising: a fourth electrode provided for the absorption chamber and positioned on the other side in the vertical direction relative to the second piezoelectric element.

10. The one side is an upper side of the first piezoelectric body, The liquid ejection head according to claim 9 , wherein the other side is a downward direction of the first piezoelectric element.

11. a direction in which the pressure chambers are arranged is a first direction; When a direction in which the pressure chamber and the absorption chamber are aligned is defined as a second direction, The second electrode extends in the second direction, The liquid ejection head according to claim 10 , wherein the fourth electrode extends in the first direction.

12. 12. The liquid ejection head according to claim 11, wherein the fourth electrode is provided so as to overlap with a center of the absorption chamber in the second direction.

13. 12. The liquid ejection head according to claim 11, wherein the fourth electrode is configured to have a bellows shape that is folded back in sequence while extending in the second direction.

14. a nozzle substrate provided with nozzles for ejecting liquid; a pressure chamber substrate having a pressure chamber in which pressure is applied to the liquid for ejecting the liquid from the nozzle, and an absorption chamber adjacent to the pressure chamber, which absorbs vibrations of the liquid generated when pressure is applied to the liquid in the pressure chamber; a first piezoelectric body provided corresponding to the pressure chamber and applying pressure to the pressure chamber when a voltage is applied thereto; a liquid ejection head including a second piezoelectric body provided in correspondence with the absorption chamber; a pressure acquisition section that acquires a pressure in the absorption chamber based on a voltage applied to the second piezoelectric body.

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