Liquid ejection head and liquid ejection apparatus

Abstract

The invention provides a liquid ejection head and a liquid ejection apparatus. The liquid ejection head can detect the pressure of an absorption chamber in the vicinity of a pressure chamber. The liquid ejection head includes: a nozzle substrate provided with a nozzle that ejects a liquid; a pressure chamber substrate having a pressure chamber for applying a pressure for discharging the liquid from the nozzle to the liquid, and an absorption chamber adjacent to the pressure chamber and absorbing vibration of the liquid generated when the pressure is applied to the liquid in the pressure chamber; a first piezoelectric body that is provided corresponding to the pressure chamber, and that applies pressure to the pressure chamber by being applied with a voltage; a second piezoelectric body that is provided so as to correspond to the absorption chamber; and a pressure acquisition unit that acquires the pressure of the absorption chamber on the basis of the voltage across the second piezoelectric body.

Description

Technical Field

[0001] The present invention relates to a liquid ejection head and a liquid ejection device. Background Art

[0002] A liquid ejection device having a plurality of heads for ejecting liquid such as ink onto a medium such as printing paper has been proposed. In recent years, inkjet printers have attracted attention not only for printing purposes but also as devices capable of applying liquefiable materials at any location. An inkjet printer has a liquid ejection head for ejecting liquid. As a liquid ejection head, a head is known that uses a piezoelectric element to vibrate a vibration plate constituting a wall surface of a pressure chamber, thereby ejecting liquid filled in the pressure chamber from a nozzle.

[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. Since the liquid storage chamber can effectively absorb the pressure fluctuation caused by the liquid, the stability of the liquid ejection from the nozzle is improved.

[0004] 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 a large number of components. Therefore, the absorption efficiency of liquid vibration in the pressure chamber is low. It is believed that by providing the liquid storage chamber at a position adjacent to the pressure chamber, the absorption efficiency of liquid vibration can be improved.

[0005] However, in a liquid ejection head, the behavior of the liquid changes greatly depending on the pressure of the pressure chamber. Therefore, obtaining the pressure has always been a problem. The inventors have found a structure that can detect the pressure near the pressure chamber by using the liquid storage chamber in the above-mentioned method of providing a liquid storage chamber at a position adjacent to the pressure chamber with a simple structure.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-153926 Summary of the invention

[0007] A preferred embodiment of the present invention involves a liquid ejection head comprising: a nozzle substrate, which is provided with a nozzle for ejecting liquid; a pressure chamber substrate, which has a pressure chamber and an absorption chamber, the pressure chamber applies pressure to the liquid for ejecting the liquid from the nozzle, and the absorption chamber is adjacent to the pressure chamber and absorbs the vibration of the liquid generated when pressure is applied to the liquid in the pressure chamber; a first piezoelectric body, which is arranged corresponding to the pressure chamber and applies pressure to the pressure chamber by applying voltage; a second piezoelectric body, which is arranged corresponding to the absorption chamber; and a pressure acquisition unit, which acquires the pressure of the absorption chamber based on the voltage across the second piezoelectric body. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a schematic diagram illustrating the structure of the liquid ejecting device according to the first embodiment.

[0009] Figure 2 for Figure 1 Block diagram of a liquid ejection device.

[0010] Figure 3 for Figure 1 A cross-sectional view of a portion of a liquid ejection head is shown.

[0011] Figure 4 To express Figure 3 Figure 2. A diagram of a portion of the pressure chamber substrate.

[0012] Figure 5 To express Figure 3 FIG. 1 is a diagram of a portion of a sealing substrate.

[0013] Figure 6 FIG. 1 is a graph showing an example of the relationship between the electrostatic capacitance of the second piezoelectric body and the pressure.

[0014] Figure 7 To express Figure 2 FIG. 5 is a diagram of a second piezoelectric element and a third piezoelectric element.

[0015] Figure 8 It is a plan view showing a second piezoelectric element according to the second embodiment.

[0016] Fig. 9 It is a plan view showing a second piezoelectric element according to the third embodiment.

[0017] Fig.10 This is a block diagram of a liquid ejection device according to a modified example.

[0018] Fig.11 4 is a cross-sectional view of a first piezoelectric element and a second piezoelectric element according to a modified example.

[0019] Fig.12 4 is a cross-sectional view of a first piezoelectric element and a second piezoelectric element according to a modified example.

[0020] Fig.13 This is a cross-sectional view of a portion of a liquid ejection head according to a modified example. DETAILED DESCRIPTION

[0021] Hereinafter, the preferred embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in each of the drawings, the size and scale of each part are appropriately different from the actual situation, and there are also parts schematically shown for easy understanding. In addition, in the following description, as long as there is no record indicating the meaning of particularly limiting the present invention, the scope of the present invention is not limited to these modes. In addition, "element β on element α" is not limited to a structure in which element α is in direct contact with element β, but also includes a structure in which element α is not in direct contact with element β.

[0022] 1. First Implementation

[0023] 1-1. Overall Structure of Liquid Dispensing Device 100

[0024] Figure 1 This is a schematic diagram illustrating the structure of the liquid ejection device 100 involved in the first embodiment. In the following, for the convenience of explanation, the X-axis, Y-axis and Z-axis that are orthogonal to each other are appropriately used for explanation. In addition, a direction along the X-axis is marked as the X1 direction, and the direction opposite to the X1 direction is marked as the X2 direction. Similarly, a direction along the Y-axis is marked as the Y1 direction, and the direction opposite to the Y1 direction is marked as the Y2 direction. A direction along the Z-axis is marked as the Z1 direction, and the direction opposite to the Z1 direction is marked as the Z2 direction.

[0025] Figure 1 The liquid ejection device 100 is an inkjet printing device that ejects ink, which is an example of liquid, onto a medium 90. The medium 90 is typically a printing paper, but the medium 90 can be used as a printing object of any material such as a resin film or cloth. Figure 1 As illustrated, a liquid container 9 for storing ink is provided in the liquid ejection device 100. For example, an ink cartridge that is detachable from the liquid ejection device 100, a bag-shaped ink pack formed of a flexible film, or an ink tank that can be replenished with ink can be used as the liquid container 9.

[0026] The liquid ejection device 100 includes a control unit 20, a medium conveying mechanism 22, a moving mechanism 24, and a liquid ejection head 1. The control unit 20 includes, for example, 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 comprehensively controls various elements of the liquid ejection device 100.

[0027] The medium conveying mechanism 22 conveys the medium 90 in the direction along the Y axis based on the control implemented by the control unit 20. In addition, the moving mechanism 24 reciprocates the liquid ejecting head 1 along the X axis based on the control implemented by the control unit 20. The moving mechanism 24 includes a substantially box-shaped conveying body 242 for accommodating the liquid ejecting head 1, and a conveying belt 244 to which the conveying body 242 is fixed. In addition, a structure in which a plurality of liquid ejecting heads 1 are mounted on the conveying body 242, or a structure in which the liquid container 9 is mounted on the conveying body 242 together with the liquid ejecting head 1, may be adopted.

[0028] The liquid ejection head 1 ejects ink supplied from the liquid container 9 from a plurality of nozzles toward the medium 90 based on control by the control unit 20. Each liquid ejection head 1 ejects ink toward the medium 90 in parallel with the transport of the medium 90 by the medium transport mechanism 22 and the repeated reciprocation of the transport body 242, thereby forming an image on the surface of the medium 90.

[0029] Figure 2 for Figure 1 A block diagram of a liquid ejection device 100 is shown. Figure 2 As shown, the liquid ejection device 100 includes a control unit 20, a medium conveying 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 generating circuit 25. The liquid ejection head 1 includes a drive circuit 40, a plurality of first piezoelectric elements 3, a voltage applying unit 41, a pressure obtaining unit 42, one or more second piezoelectric elements 5, and one or more third piezoelectric elements 6.

[0030] The control unit 21 includes one or more processing circuits such as a CPU or an FPGA. 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 performed by the liquid ejection head 1.

[0031] The control unit 21 generates a printing signal SI, a waveform designation signal dCom, and a timing signal PTS. The printing signal SI is a digital signal for designating the type of action of the liquid ejection head 1. The printing signal SI designates whether to supply the drive signal Com to the first piezoelectric element 3. The waveform designation signal dCom is a digital signal that specifies 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 specifies the timing of generating the drive signal Com.

[0032] The storage unit 23 includes one or more storage circuits such as semiconductor memories. The storage unit 23 stores the print data Img supplied from the host computer. The storage unit 23 stores the control program of the liquid ejecting device 100.

[0033] The drive signal generation circuit 25 includes a DA conversion circuit. The drive signal generation circuit 25 generates a drive signal Com having a waveform specified by the waveform designation signal dCom. The drive signal generation circuit 25 outputs the drive signal Com every time it receives the timing signal PTS.

[0034] The drive circuit 40 switches whether 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, the latch signal LAT, and the exchange signal CH supplied from the control unit 20. The latch signal LAT specifies the latch timing of the print data Img. The exchange signal CH specifies the selection timing of the drive pulse included in the drive signal Com.

[0035] The voltage applying unit 41 applies a predetermined voltage to one or more second piezoelectric elements 5 and one or more third piezoelectric elements 6. The voltage applying unit 41 includes, for example, a power supply circuit. The pressure acquiring unit 42 acquires the pressure of the absorption chamber S2 described later of the liquid ejection head 1 based on the voltage across the second piezoelectric element 5. The pressure acquiring unit 42 includes, for example, a pressure detection element, and outputs a detection signal as a voltage value.

[0036] 1-2. Liquid ejection head 1

[0037] Figure 3 for Figure 1 The cross-sectional view of a portion of the liquid ejection head 1 shown is a cross-sectional view parallel to the XZ plane. The Z axis is the axis along the ejection direction of the ink achieved by the liquid ejection head 1. The direction along the Z axis is set as the "up and down direction". The Z2 direction is an example of "one side in the up and down direction", and the Z1 direction is an example of "the other side in the up and down direction". In addition, observation from the direction along the Z axis is set as "planar observation". The Y1 direction or the Y2 direction is an example of the "first direction". The X1 direction or the X2 direction is an example of the "second direction".

[0038] Figure 3 The liquid ejection head 1 is a structure that is substantially plane-symmetrical with respect to an imaginary plane a along the Y-Z plane. Figure 3 The structure on the right side of the figure is described, and the structure close to the imaginary plane a is omitted appropriately. Figure 3 Description of the structure on the left.

[0039] The liquid ejection head 1 includes 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. In addition, although not shown in detail, the nozzle substrate 11, the pressure chamber substrate 12, the vibration plate 13, and the sealing substrate 14 are in the shape of a long and narrow plate along the Y axis.

[0040] The nozzle substrate 11 is a plate-shaped member provided with a plurality of nozzles N for ejecting ink as an example of liquid. The plurality of nozzles N are circular through holes for ejecting ink. The plurality of nozzles N are arranged in a straight line along the Y axis. The nozzle substrate 11 is manufactured by processing a semiconductor substrate such as a single crystal silicon substrate, for example.

[0041] The pressure chamber substrate 12 is a flow channel structure having flow channels formed therein for supplying ink to the plurality of nozzles N. The pressure chamber substrate 12 is a laminate of a first substrate 121 and a second substrate 122. The first substrate 121 and the second substrate 122 are manufactured by processing semiconductor substrates such as single crystal silicon substrates, for example. In addition, each of the first substrate 121 and the second substrate 122 may be formed integrally. In addition, the pressure chamber substrate 12 may also include components other than the first substrate 121 and the second substrate 122.

[0042] The flow path of the ink is formed on the pressure chamber substrate 12. Specifically, a plurality of pressure chambers S1, an absorption chamber S2, a plurality of first communication flow paths R1, and a second communication flow path R2 are formed on the pressure chamber substrate 12. The first substrate 121 and the second substrate 122 respectively have recesses or through holes, and the plurality of pressure chambers S1, the absorption chamber S2, a plurality of first communication flow paths R1, and a second communication flow path R2 are formed through these recesses or through holes.

[0043] Figure 4 To express Figure 3 FIG. 1 is a diagram of a portion of a pressure chamber substrate 12. Figure 4 As shown, each pressure chamber S1 is a narrow and long shape extending in the X2 direction. The plurality of pressure chambers S1 are separated from each other and arranged in the Y2 direction. Therefore, the direction in which the plurality of pressure chambers S1 are arranged is the Y2 direction as the "first direction". In addition, the plurality of pressure chambers S1 are provided in a one-to-one manner with the plurality of nozzles N. Each pressure chamber S1 is a space for applying pressure to the ink for ejecting the ink from the nozzle N.

[0044] The plurality of first communication channels R1 are separated from each other and arranged in the Y2 direction. The plurality of first communication channels R1 are arranged in a one-to-one manner with the plurality of pressure chambers S1. Each first communication channel R1 connects the corresponding pressure chamber S1 with the nozzle N. Each first communication channel R1 overlaps with the corresponding pressure chamber S1 and the nozzle N when viewed in a plan view.

[0045] The absorption chamber S2 is provided at the upstream side relative to the plurality of pressure chambers S1. The direction in which the pressure chambers S1 and the absorption chamber S2 are arranged is the X2 direction, which is the "second direction". The absorption chamber S2 is a long and narrow shape extending in the Y2 direction. The volume of the absorption chamber S2 is very large compared to the volume of each pressure chamber S1. The absorption chamber S2 is provided in common with the plurality of pressure chambers S1 and is connected to the plurality of pressure chambers S1. The absorption chamber S2 is adjacent to the pressure chamber S1 and 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 addition, by making the absorption chamber S2 adjacent to the pressure chamber S1, the absorption efficiency of the ink vibration can be improved compared to the case where the absorption chamber S2 is separated from the pressure chamber S1. Therefore, the stability of the ink ejection performance can be improved.

[0046] The second communication flow passage R2 is provided at the upstream side of the absorption chamber S2 and is connected to the absorption chamber S2. The second communication flow passage R2 is in a long and narrow shape extending in the Y2 direction.

[0047] like Figure 3 As shown, a vibration plate 13 is arranged on the surface of the pressure chamber substrate 12 in the Z2 direction. The thickness of the vibration plate 13 is very thin compared with the thickness 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 can be elastically deformed. The vibration plate 13 includes a plurality of first vibration plates 131 and a second vibration plate 132. The plurality of first vibration plates 131 and the second vibration plate 132 are formed by one component.

[0048] The plurality of first vibration plates 131 are arranged one-to-one with the plurality of pressure chambers S1. Each first vibration plate 131 is a portion of the vibration plate 13 that overlaps with the plurality of pressure chambers S1 when viewed from a plane. Each first vibration plate 131 forms a portion of the pressure chamber S1. Each first vibration plate 131 vibrates by applying a voltage to the first piezoelectric body 31 of the first piezoelectric element 3, and applies pressure to the pressure chamber S1. By providing the first vibration plate 131, the first piezoelectric element 3 can be provided on the pressure chamber S1, and the pressure generated by the vibration generated by applying a voltage to the first piezoelectric body 31 through the first vibration plate 131 can be efficiently applied to the pressure chamber S1.

[0049] The second vibration plate 132 is a portion of the vibration plate 13 that overlaps with the absorption chamber S2 when viewed from a plane. The second vibration plate 132 forms a portion of the absorption chamber S2. The second vibration plate 132 is driven by the 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 on the absorption chamber S2, and pressure can be applied to the second piezoelectric body 51 efficiently.

[0050] In addition, the plurality of first vibration plates 131 and the second vibration plates 132 are not separated but formed by one continuous member. Therefore, it is easy to make each first vibration plate 131 adjacent to the second vibration plate 132. Therefore, it is easy to make the plurality of pressure chambers S1 adjacent to the absorption chamber S2. Since the plurality of pressure chambers S1 can be adjacent to the absorption chamber S2, the absorption efficiency of the vibration of the ink can be improved.

[0051] The vibration plate 13 is manufactured by processing a semiconductor substrate such as a single crystal silicon substrate, for example. Alternatively, the vibration plate 13 may be formed by a portion of the pressure chamber substrate 12. For example, the vibration plate 13 may be formed by thinning a portion of the second substrate 122.

[0052] 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 described later and reinforces the mechanical strength of the pressure chamber substrate 12.

[0053] The third communication channel R3, the first space H1, the second space H2, and the wiring space H0 are formed on the sealing substrate 14. The sealing substrate 14 has a recess or a through hole, and each channel or space is formed through these recesses or through holes. The third communication channel R3 and the wiring space H0 are holes that penetrate the sealing substrate 14. The first space H1 and the second space H2 are spaces surrounded by the recess formed on the sealing substrate 14.

[0054] The third communication flow channel R3 overlaps with the second communication flow channel R2 when viewed in a plan view, and is connected to the second communication flow channel R2. A common ink chamber R is formed by the third communication flow channel R3 and the second communication flow channel R2. The common ink chamber R functions as a liquid reservoir. In addition, a filter 141 for removing bubbles and foreign matter mixed in the ink is provided at a portion overlapping with the common ink chamber R when viewed in a plan view. The filter 141 may also be omitted.

[0055] Figure 5 To express Figure 3 A plan view of a portion of the sealing substrate 14 is shown. Figure 5 In the figure, for ease of understanding, the second electrode 33 of the first piezoelectric element 3 and the third electrode 52 of the second piezoelectric element 5 are marked with dots.

[0056] like Figure 5 As shown, the first space H1, the second space H2, the third communication channel R3 and the wiring space H0 are each long and narrow and extend 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.

[0057] like Figure 3 As shown, 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 substrate 49 is arranged in the wiring space H0. The wiring substrate 49 and the pressure chamber substrate 12 are bonded together. The wiring substrate 49 is a mounting component formed with a plurality of wirings for electrically connecting the control unit 20 and the liquid ejection head 1. As the wiring substrate 49, for example, TCP (Tape Carrier Package) or FPC (Flexible Printed Circuit) can be used.

[0058] Each first piezoelectric element 3 is in a long and narrow shape extending in the X2 direction. The plurality of first piezoelectric elements 3 are separated from each other and arranged in the Y2 direction. The plurality of first piezoelectric elements 3 are arranged in a one-to-one manner with the plurality of pressure chambers S1. In addition, the second piezoelectric element 5 is in a long and narrow shape extending in the Y2 direction, and extends in a direction intersecting the plurality of first piezoelectric elements 3. The second piezoelectric element 5 is arranged corresponding to the absorption chamber S2, and overlaps with the absorption chamber S2 when viewed in a plan view.

[0059] The first piezoelectric element 3 is provided corresponding to the pressure chamber S1. Specifically, the first piezoelectric element 3 is arranged on a surface of the first vibration plate 131 opposite to the pressure chamber S1 for each pressure chamber S1. The first piezoelectric element 3 is an energy generating element that generates energy for ejecting ink by applying a driving signal Com. In addition, the first piezoelectric element 3 is also a driving element that is driven by applying a driving signal Com. The first piezoelectric element 3 contracts when a voltage is applied, so that the first vibration plate 131 is bent, thereby pressurizing the pressure chamber S1.

[0060] The first piezoelectric element 3 schematically 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 "upper direction" of the "one side in the up-down direction", that is, the Z2 direction, compared to the first piezoelectric body 31. The second electrode 33 is located in the "lower direction" of the "other side in the up-down direction", that is, the Z1 direction, compared to the first piezoelectric body 31. By providing the first electrode 32 and the second electrode 33, a voltage can be efficiently applied to the first piezoelectric body 31. In addition, the second electrode 33 and the first vibration plate 131 may be in contact with each other, or there may be other components between the second electrode 33 and the first vibration plate 131.

[0061] The first piezoelectric body 31 is a dielectric provided separately for each of the plurality of first piezoelectric elements 3. In addition, the plurality of first piezoelectric bodies 31 may also be connected to each other. The plurality of first piezoelectric bodies 31 may also be separated, for example, by forming a plurality of cuts on a strip-shaped dielectric film extending along the Y2 direction. Therefore, the plurality of first piezoelectric bodies 31 may also be formed by one dielectric film. The first piezoelectric body 31 is formed, for example, using a known piezoelectric material such as lead zirconate titanate (Pb(Zr, Ti)O3).

[0062] The first electrode 32 is a common electrode commonly provided for the plurality of first piezoelectric bodies 31. The first electrode 32 is in the shape of a strip extending in the Y2 direction in a continuous manner across the plurality of first piezoelectric elements 3. The second electrode 33 is commonly provided for the plurality of pressure chambers S1. By providing the first piezoelectric elements 3 in common, it is easier to miniaturize the first piezoelectric elements 3 than when they are provided individually. The first electrode 32 is formed of a low-resistance conductive material such as platinum (Pt) or iridium (Ir), similarly to the second electrode 33.

[0063] like Figure 5 As shown in the figure, the second electrode 33 is long and narrow along the X-axis. A plurality of second electrodes 33 are arranged along the Y-axis. The second electrode 33 is a separate electrode formed separately from each other for each first piezoelectric element 3. The second electrode 33 is separately provided with respect to the plurality of pressure chambers S1. By separately providing, even when a plurality of first piezoelectric bodies 31 are formed by a single dielectric film, a single dielectric film can be divided into a plurality of first piezoelectric bodies 31. The second electrode 33 is formed, for example, using a conductive material such as platinum or iridium.

[0064] The first piezoelectric element 3 is a piezoelectric element related to the ejection of ink. A reference voltage as a constant voltage is applied to the first electrode 32. The reference voltage can be, for example, a ground voltage or a voltage higher than the ground voltage. A driving signal Com is supplied to the second electrode 33. Therefore, a driving voltage that changes with time is applied to the second electrode 33.

[0065] A voltage corresponding to the difference between the reference voltage applied to the first electrode 32 and the driving voltage supplied to the second electrode 33 is applied to the first piezoelectric body 31. Figure 2 The driving circuit 40 applies a driving voltage that changes the voltage according to time to the first piezoelectric body 31. The first piezoelectric body 31 is deformed by applying a voltage corresponding to the difference between the reference voltage applied to the first electrode 32 and the driving voltage supplied to the second electrode 33 to the first piezoelectric body 31, so that the first piezoelectric element 3 generates energy that flexibly deforms the first vibration plate 131. Therefore, the first piezoelectric element 3 applies pressure to the pressure chamber S1 by the application of this voltage. By utilizing the energy generated by the first piezoelectric element 3 to flexibly deform the first vibration plate 131, the pressure in the pressure chamber S1 changes, and the ink in the pressure chamber S1 is moved from the first vibration plate 131 to the second vibration plate 131. Figure 3 The nozzle N shown is sprayed.

[0066] Figure 3 The second piezoelectric element 5 shown is provided corresponding to the absorption chamber S2. Specifically, the second piezoelectric element 5 is arranged on the surface of the first vibration plate 131 which is opposite to the absorption chamber S2. The second piezoelectric element 5 is used to detect the pressure of the absorption chamber S2. The second piezoelectric element 5 is deformed according to the second vibration plate 132 which is bent according to the pressure of the absorption chamber S2.

[0067] The second piezoelectric element 5 includes 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 stacked in this order from the second vibration plate 132. In addition, the fourth electrode 53 and the second vibration plate 132 may be in contact with each other, or another component may be present between the fourth electrode 53 and the second vibration plate 132.

[0068] The second piezoelectric body 51 is a strip-shaped dielectric film extending in the Y2 direction. The second piezoelectric body 51 is formed, for example, using a known piezoelectric material such as lead zirconate titanate. The thickness of the second piezoelectric body 51 is the same as the thickness of the first piezoelectric body 31. In addition, the thickness refers to the length in the Z1 direction. In addition, the third electrode 52 and the fourth electrode 53 are respectively long and narrow along the Y axis. The third electrode 52 and the fourth electrode 53 are respectively formed, for example, using a conductive material such as platinum or iridium.

[0069] Although in Figure 5 The fourth electrode 53 is illustrated in the figure, but the plane areas of the third electrode 52 and the second piezoelectric body 51 are substantially the same as the plane areas of the fourth electrode 53, and the third electrode 52 and the second piezoelectric body 51 overlap with the fourth electrode 53 when viewed in a plane. In addition, the second piezoelectric body 51, the third electrode 52, and the fourth electrode 53 overlap with substantially the entire area of ​​the absorption chamber S2 when viewed in a plane.

[0070] As described above, in the liquid ejection head 1 of the present embodiment, the pressure chamber S1 and the absorption chamber S2 are provided on the pressure chamber substrate 12, and the pressure chamber S1 is adjacent to the absorption chamber S2. In the manner in which the pressure chamber S1 is adjacent to the absorption chamber S2, the second piezoelectric body 51 is provided corresponding to the absorption chamber S2. In addition, in the liquid ejection head 1, a pressure acquisition unit 42 is provided for acquiring the pressure of the absorption chamber S2 based on the voltage across the second piezoelectric body 51.

[0071] As described above, the absorption chamber S2 is a space for absorbing the vibration of the ink generated 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 the present embodiment, a 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 across the second piezoelectric body 51. Therefore, the pressure near the pressure chamber S1 can be detected by using the absorption chamber S2. Therefore, it is not necessary to form a space for detecting the pressure near the pressure chamber S1 separately, but the pressure near the pressure chamber S1 can be detected with a simple structure. Since the pressure of the absorption chamber S2 near the pressure chamber S1 can be obtained, the behavior of the ink corresponding to the pressure of the pressure chamber S1 can be detected. Therefore, for example, various adverse conditions such as insufficient supply of ink to multiple pressure chambers S1 and the absorption chamber S2 can be detected. Therefore, since the pressure of the absorption chamber S2 near the pressure chamber S1 can be obtained, it can help improve the quality of the liquid ejection head 1.

[0072] Furthermore, the absorption chamber S2 is not directly related to the ejection of ink like the pressure chamber S1. Therefore, the pressure of the absorption chamber S2 can be detected based on the voltage across the second piezoelectric body 51 regardless of the ejection of ink and can be always detected.

[0073] Furthermore, in the present embodiment, the electrostatic capacitance C2 is obtained based on the voltage across the second piezoelectric body 51, and the pressure of the absorption chamber S2 is detected based on the electrostatic capacitance C2.

[0074] The electrostatic 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 in a manner that bends in the Z1 direction or the Z2 direction. When the second vibration plate 132 is deformed, stress is applied to the second piezoelectric body 51 on the second vibration plate 132. By applying stress to the second piezoelectric body 51, the polarization state of the second piezoelectric body 51 is changed. By expressing the change in the polarization state as a change in the dielectric constant ε of the second piezoelectric body 51, the electrostatic capacitance C changes. Therefore, according to the change in the pressure in the absorption chamber S2, the electrostatic capacitance C changes.

[0075] The electrostatic capacitance C is expressed by equation [1].

[0076] C = ε(S / d)…[1]

[0077] S is the electrode area. d is the distance between the third electrode 52 and the fourth electrode 53.

[0078] Figure 6 : is a graph showing an example of the relationship between the electrostatic capacitance C2 of the second piezoelectric body 51 and the pressure P. Figure 6 The horizontal axis is pressure P [kPa], and the vertical axis is electrostatic capacitance C2 [nF]. Figure 6 In the illustrated example, as the pressure P increases, the electrostatic capacitance C of the second piezoelectric body 51 decreases.

[0079] like Figure 6 As shown, since the electrostatic capacitance C2 of the second piezoelectric body 51 is correlated with the pressure P, the pressure of the absorption chamber S2 can be detected based on the electrostatic capacitance C2 by using the second piezoelectric body 51. Figure 2 The pressure acquisition unit 42 acquires the capacitance C2 of the second piezoelectric body 51 based on the voltage across the second piezoelectric body 51, and acquires the pressure of the absorption chamber S2 based on the capacitance C2. Since the pressure of the absorption chamber S2 can be detected based on the capacitance C2 by providing the second piezoelectric body 51 and the pressure acquisition unit 42, a slight change in pressure can be detected.

[0080] Figure 7 To express Figure 2 FIG. 5 is a diagram of a second piezoelectric element 5 and a third piezoelectric element 6 . Figure 7 The third piezoelectric element 6 is a reference piezoelectric element. The third piezoelectric element 6 is connected in series with the second piezoelectric element 5. The third piezoelectric element 6 is not disposed on the aforementioned vibration plate 13 but is provided at a location that is not deformed by the pressure in the flow channel.

[0081] The third piezoelectric element 6 has the same structure 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 by the fifth electrode 62 and the sixth electrode 63. The third piezoelectric body 61 is a dielectric, and is formed using a known piezoelectric material such as lead zirconate titanate. The electrostatic capacitance of the third piezoelectric body 61 is known.

[0082] The fifth electrode 62 and the sixth electrode 63 are formed of conductive materials such as platinum or iridium, for example. The fifth electrode 62 is electrically connected to the fourth electrode 53 of the second piezoelectric element 5. A certain predetermined voltage is applied to the sixth electrode 63. In the example shown in the figure, the predetermined voltage is a ground voltage, and the sixth electrode 63 is grounded. In addition, a certain predetermined voltage Vx different from the voltage across the sixth electrode 63 is applied to the third electrode 52 of the second piezoelectric element 5. Therefore, Figure 2 The voltage applying unit 41 applies a predetermined voltage Vx to the second piezoelectric body 51 and the third piezoelectric body 61 .

[0083] As shown in [4] below, the capacitance C2 of the second piezoelectric body 51 can be obtained based on the voltage V2 across the second piezoelectric body 51, the voltage V3 across the third piezoelectric body 61, and the capacitance C3 of the third piezoelectric body 61.

[0084] V2=C2×Q2 …[2]

[0085] V3=C3×Q3 …[3]

[0086] C2=(V2 / V3)×C3 …[4]

[0087] Formula [4] is derived from Formula [2] and Formula [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 across the second piezoelectric body 51 when the predetermined voltage Vx is applied by the voltage applying unit 41. Voltage V3 is the voltage across the third piezoelectric body 61 when the predetermined voltage Vx is applied by the voltage applying unit 41.

[0088] When stress is applied to the second piezoelectric body 51 and the capacitance C2 of the second piezoelectric body 51 changes, the voltage V2 across the second piezoelectric body 51 changes. Figure 2 The pressure acquisition unit 42 acquires the signal of the voltage V2. The voltage V2, the voltage V3, and the known electrostatic capacitance C3 are used to obtain the electrostatic capacitance C2 of the second piezoelectric body 51 by using equation [4]. Therefore, the pressure acquisition unit 42 acquires the electrostatic capacitance C2 based on the voltage V2, the voltage V3, and the electrostatic capacitance C3. Figure 6The pressure P of the second piezoelectric body 51 is obtained by using the correlation between the electrostatic capacitance C2 and the pressure P. In this manner, the pressure acquisition unit 42 acquires the pressure of the absorption chamber S2 based on the electrostatic capacitance C2.

[0089] In this embodiment, as described above, the pressure acquisition unit 42 uses the third piezoelectric body 61 whose electrostatic capacitance C3 is known to obtain the electrostatic capacitance C2 of the second piezoelectric body 51, and detects the pressure of the absorption chamber S2 through the electrostatic capacitance C2. According to the detection method using the third piezoelectric body 61, the pressure of the absorption chamber S2 near the pressure chamber S1 can be detected with a simple structure. In addition, the method for detecting the pressure of the absorption chamber S2 is not limited to the detection method using the third piezoelectric body 61, and the third piezoelectric element 6 can also be omitted according to the detection method.

[0090] In addition, as described above, at least a plurality of pressure chambers S1 and an absorption chamber S2 commonly connected to the plurality of pressure chambers S1 are provided on the pressure chamber substrate 12. 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 achieved by the absorption chamber S2 can be improved. In addition, by being able to detect the pressure of an absorption chamber S2 commonly connected to a plurality of pressure chambers S1, it is possible to detect the pressure of the absorption chamber S2 caused by the influence of the plurality of pressure chambers S1, rather than the pressure of each pressure chamber S1. Therefore, the pressure can be used to detect various adverse conditions such as whether insufficient ink supply has occurred.

[0091] In addition, as mentioned above Figure 5 As shown, the second electrode 33 extends in the X2 direction. The fourth electrode 53 extends in the Y2 direction. The Y2 direction as the "first direction" is the direction in which the plurality of pressure chambers are arranged. The X2 direction as the "second direction" is the direction in which the pressure chambers S1 and the absorption chambers S2 are arranged.

[0092] In the first piezoelectric body 31 and the second piezoelectric body 51, the directions in which bending is easy to occur are different from each other. The pressure chamber S1, the first piezoelectric body 31 and the second electrode 33 are long and narrow along the X2 direction. If the exclusion volume is to be increased as much as possible during the extension of the pressure chamber S1 in the X2 direction, the first piezoelectric body 31 and the second electrode 33 are also easy to extend in the X2 direction. Therefore, the first piezoelectric body 31 and the second electrode 33 are easy to bend with the center near the center of the X2 direction as the center. Therefore, by setting the first piezoelectric body 31 along the extension direction of the pressure chamber S1, the ejection accuracy can be improved.

[0093] On the other hand, the absorption chamber S2, the second piezoelectric body 51 and the fourth electrode 53 are long and narrow along the Y2 direction. Therefore, the second piezoelectric body 51 and the fourth electrode 53 are easily bent with the center near the Y2 direction as the center. In addition, the absorption chamber S2 is commonly provided relative to the plurality of pressure chambers S1, and the absorption chamber S2 is commonly given pressure from the plurality of pressure chambers S1. It is difficult to imagine a situation where pressure is concentratedly given only from a specific pressure chamber S1. From this point of view, the second piezoelectric body 51 and the fourth electrode 53 are also easily bent with the center near the Y2 direction as the center. Therefore, by providing the second piezoelectric body 51 along the extension direction of the absorption chamber S2, the pressure detection sensitivity can be improved.

[0094] Alternatively, for example, the second piezoelectric body 51 and the fourth electrode 53 may be arranged along the X2 direction. However, in this case, the deflection of the second piezoelectric body 51 and the fourth electrode 53 is smaller than when the second piezoelectric body 51 and the fourth electrode 53 are arranged along the X2 direction.

[0095] In addition, if Figure 5 As shown, 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 with the largest displacement. Therefore, by overlapping the fourth electrode 53 and the second piezoelectric body 51 in 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. In addition, the fourth electrode 53 and the second piezoelectric body 51 do not need to overlap in the center in the X2 direction.

[0096] According to the present embodiment described above, the pressure in the vicinity of the pressure chamber S1 can be acquired by utilizing the absorption chamber S2 which is a space for absorbing vibration of ink.

[0097] 2. Second Implementation

[0098] In the following exemplary embodiments, elements having the same actions and functions as those of the first embodiment are assigned the same reference numerals as those of the first embodiment, and detailed descriptions thereof are appropriately omitted.

[0099] Figure 8 1 is a plan view showing a second piezoelectric element 5A according to the second embodiment. Figure 8 The second piezoelectric element 5A shown does not overlap the entire area of ​​the absorption chamber S2 when viewed in a plan view. Therefore, the second piezoelectric body 51 of the second piezoelectric element 5A is not disposed in the entire area of ​​the absorption chamber S2 when viewed in a plan view. For example, the length of the second piezoelectric body 51 in the X2 direction is less than half of the length of the absorption chamber S2 and the second vibration plate 132 in the X2 direction.

[0100] Since the second piezoelectric body 51 is not disposed in the entire region of the absorption chamber S2 when viewed in a plan view, the second vibration plate 132 is more likely to be deformed than when it is disposed in the entire region. By disposing the second piezoelectric body 51 so as to overlap the center of the second vibration plate 132 in the X2 direction where the displacement is most likely to occur, the detection accuracy of the pressure in the absorption chamber S2 can be improved.

[0101] 3. Third Implementation

[0102] In the following exemplary embodiments, elements having the same actions and functions as those of the first embodiment are assigned the same reference numerals as those of the first embodiment, and detailed descriptions thereof are appropriately omitted.

[0103] Fig. 9 1 is a plan view showing a second piezoelectric element 5B according to the third embodiment. Fig. 9 The second piezoelectric element 5B shown has a corrugated shape extending along the X2 direction and being sequentially folded back toward the Y2 direction.

[0104] The second piezoelectric element 5 includes a plurality of first parts 501 and a plurality of second parts 502. The plurality of first parts 501 are parts extending in the X2 direction, which are separated from each other and arranged in the Y2 direction. The plurality of second parts 502 are parts extending in the Y2 direction. Each second part 502 is arranged between two adjacent first parts 501 and connects the two adjacent first parts 501. The plurality of second parts 502 are alternately arranged at the ends of the first part 501 in the X1 direction and the ends in the X2 direction. The second part 502 located closest to the Y1 direction among the plurality of second parts 502 is set as the first, and the plurality of second parts 502 are counted in the Y2 direction. In this case, for example, the odd-numbered second parts 502 among the plurality of second parts 502 are connected to the ends of the first part 501 in the X2 direction. The even-numbered second parts 502 among the plurality of second parts 502 are connected to the ends of the first part 501 in the X1 direction.

[0105] Furthermore, the length of one first portion 501 is longer than the length of one second portion 502. As a result, the first portion 501 alternately bends in the X1 direction and the X2 direction, and the second portion 502 gradually deviates in the Y2 direction, thereby forming a shape that extends in the Y2 direction as a whole. This shape is referred to as a shape that "extends in the X2 direction and bends back in sequence."

[0106] The second piezoelectric body 51, the third electrode 52, and the fourth electrode 53 of the second piezoelectric element 5B are configured in a pleated shape that is folded back in sequence while extending in the X2 direction. By making the second piezoelectric element 5B into a pleated shape, the second piezoelectric element 5B is more likely to withstand the stress generated by the deformation of the second vibration plate 132 than the case where the second piezoelectric element 5 of the first embodiment is a narrow and long shape along the Y2 direction. In addition, by making the second piezoelectric element 5B into a pleated shape, the plane area is reduced compared with the second piezoelectric element 5 of the first embodiment. Therefore, the volume of the second piezoelectric element 5 on the second vibration plate 132 can be reduced. Therefore, the second vibration plate 132 is easily deformed. Therefore, the detection accuracy of the pressure of the absorption chamber S2 can be improved.

[0107] In addition, the shape of the second piezoelectric element 5 is preferably a shape that can easily receive stress caused by deformation of the second vibration plate 132 , and is not limited to the corrugated shape shown in the figure.

[0108] 4. Modifications

[0109] The above-described embodiments may be modified in various ways. In the following, specific modified methods that can be applied to the above-described embodiments are illustrated. Two or more methods arbitrarily selected from the following examples may be appropriately combined within a range that is not contradictory to each other.

[0110] Fig.10 1 is a block diagram of a liquid ejection device 100a of a modified example. The liquid ejection device 100a includes a liquid ejection head 1a and a control unit 20a. The control unit 20a is provided with a drive circuit 40, a voltage application unit 41, and a pressure acquisition unit 42. The liquid ejection head 1a does not have a voltage application unit 41 and a pressure acquisition unit 42.

[0111] like Fig.11 As shown, the driving circuit 40, the voltage applying unit 41, and the pressure acquiring unit 42 may be partially or entirely provided on the control unit 20. With the liquid ejecting device 100a, as in the respective embodiments, the pressure near the pressure chamber S1 can be acquired by using the absorption chamber S2 which is a space for absorbing vibration of the ink.

[0112] Fig.11 as well as Fig.12 The first and second piezoelectric elements 3 and 5 are cross-sectional views of modified examples. The thickness D5 of the second piezoelectric body 51 of the second piezoelectric element 5 may be different from the thickness D3 of the first piezoelectric body 31 of the first piezoelectric element 3 .

[0113] 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 D5 thinner, the second piezoelectric body 51 is easier to deform than the first piezoelectric body 31. The first piezoelectric body 31 works actively, while the second piezoelectric body 51 works passively. Therefore, by making the thickness D5 thinner than the thickness D3, the detection accuracy of the pressure of the absorption chamber S2 can be improved compared with the case where the thickness D5 is thicker. On the other hand, the first piezoelectric body 31 is a portion that contributes to the ejection. Therefore, by making the thickness D3 thicker than the thickness D5, cracks and the like can be reduced.

[0114] For example, in Fig.12 , the thickness D5 of the second piezoelectric body 51 is thicker than the thickness D3 of the first piezoelectric body 31. By making the thickness D5 thicker than the thickness D3, that is, by making the thickness D3 thinner than the thickness D5, the first piezoelectric body 31 is more easily deformed than the second piezoelectric body 51. Therefore, the ink ejection performance can be improved.

[0115] Furthermore, the “liquid ejection head” may be a circulation type head having a so-called circulation flow path.

[0116] Fig.13 It is a cross-sectional view of a part of the liquid ejection head 10 according to a modified example. Fig.13 The liquid ejection head 10 shown has a nozzle substrate 11 , a pressure chamber substrate 120 , a vibration plate 130 , a sealing substrate 140 , a housing 150 , a wiring substrate 49 , a first piezoelectric element 3 , a second piezoelectric element 4 , and a fourth piezoelectric element 7 . Fig.13 The liquid ejection head 10 is a circulation type head having a so-called circulation flow path.

[0117] The pressure chamber substrate 120 is a laminate of a third substrate 124 and a fourth substrate 125. These substrates are manufactured by processing semiconductor substrates such as single crystal silicon substrates, for example. In addition to a plurality of pressure chambers S1, absorption chambers 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 on the pressure chamber substrate 120. The absorption chamber S2 is a supply side absorption chamber.

[0118] One first communication flow channel R1 is connected to one fifth communication flow channel R5 via one fourth communication flow channel R4. Each fourth communication flow channel R4 overlaps with the nozzle N when viewed in plan. Each fifth communication flow channel R5 is connected to the discharge side absorption chamber S3. The discharge side absorption chamber S3 overlaps with the fourth piezoelectric element 7 when viewed in plan. Multiple discharge side absorption chambers S3 are connected to the sixth communication flow channel R6.

[0119] The vibration plate 130 includes a third vibration plate 133 in addition to the plurality of first vibration plates 131 and the second vibration plate 132. The third vibration plate 133 is a portion of the vibration plate 130 that overlaps with the discharge-side absorption chamber S3 in plan view.

[0120] The housing 150 is in contact with the sealing substrate 140. In addition, the housing 150 and the sealing substrate 140 may be integrated. The third communication flow channel R3 and the seventh communication flow channel R7 are formed on the housing 150. The common ink chamber R0 is formed by the seventh communication flow channel R7 and the sixth communication flow channel R6.

[0121] In addition to the first space H1, the second space H2, and the wiring space H0, a third space H3 is formed on 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 vibration plate 133 that is opposite to the discharge side absorption chamber S3. The fourth piezoelectric element 7 is used to detect the pressure of the discharge side absorption chamber S3. The fourth piezoelectric element 7 is deformed according to the third vibration plate 133 that is bent according to the pressure of the discharge side absorption chamber S3.

[0122] The fourth piezoelectric element 7 has a seventh electrode 72, a third piezoelectric body 71, and an eighth electrode 73. These components are long and narrow along the Y axis. The eighth electrode 73, the third piezoelectric body 71, and the seventh electrode 72 are stacked in this order from the third vibration plate 133. The third piezoelectric body 71 is formed using a known piezoelectric material such as lead zirconate titanate. The seventh electrode 72 and the eighth electrode 73 are formed using a conductive material such as platinum or iridium, respectively. The fourth piezoelectric element 7 is not a component that applies pressure to the liquid in the flow channel, but a component for absorbing vibration.

[0123] In addition, although the third vibration plate 133, the fourth piezoelectric element 7, and the discharge side absorption chamber S3 are long and narrow along the Y axis and are provided with respect to the plurality of pressure chambers S1, these components may be provided for each pressure chamber S1. Therefore, the third vibration plate 133, the fourth piezoelectric element 7, and the discharge side absorption chamber S3 may each be provided in plurality.

[0124] In the liquid ejection head 10, ink flows to the pressure chamber S1 via the common ink chamber R and the absorption chamber S2. The pressure of the pressure chamber S1 is changed by driving the first piezoelectric element 3, and the change in pressure causes the ink to be ejected from the nozzle N as ink droplets via the first communication flow channel R1 and the fourth communication flow channel R4. At the same time, the ink flows back through the fifth communication flow channel R5, the discharge side absorption chamber S3, and the common ink chamber R0. In this way, the ink is circulated.

[0125] In addition, 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. That is, a vibration absorbing mechanism is provided at the supply side and the discharge side of the ink relative to the pressure chamber S1. In addition, 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 using the absorption chamber S2 closer to the pressure chamber S1 to detect the pressure near the pressure chamber S1, the behavior of the ink corresponding to the pressure of the pressure chamber S1 can be detected with better accuracy.

[0126] In addition to equipment dedicated to printing, "liquid ejection devices" can also be used in various equipment such as fax machines or copiers. The use of liquid ejection devices is not limited to printing. For example, a liquid ejection device that ejects a solution of a color material can be used as a manufacturing device for forming a color filter for a display device such as a liquid crystal display panel. In addition, a liquid ejection device that ejects a solution of a conductive material can be used as a manufacturing device for forming wiring and electrodes of a wiring substrate. In addition, a liquid ejection device that ejects a solution of an organic substance related to a living body can be used as a manufacturing device for manufacturing a biochip, for example.

[0127] Although the present invention has been described above based on preferred embodiments, the present invention is not limited to the aforementioned embodiments. In addition, the structure of each part of the present invention can be replaced with an arbitrary structure that exerts the same function as the aforementioned embodiments, and an arbitrary structure can be added.

[0128] Explanation of symbols

[0129] 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…vibration plate; 14…sealing substrate; 20…control unit; 21…control unit; 22…medium conveying mechanism; 23…storage unit; 24…moving mechanism; 25…driving signal generating circuit; 31…first piezoelectric body; 32…first electrode; 33…second electrode; 40…driving circuit; 41…voltage applying unit; 42…pressure acquiring unit; 49…wiring substrate; 51…second piezoelectric body; 52…third electrode; 53…fourth electrode; 61…third piezoelectric body; 62…first piezoelectric body; 63…second electrode; 64…third piezoelectric body; 65…third piezoelectric body; 66…third piezoelectric body; 67…third piezoelectric body; 68…third piezoelectric body; 69…third piezoelectric body; 70…third piezoelectric body; 71…third piezoelectric body; 72…first electrode; 73…second electrode; 74…third electrode; 75…third piezoelectric body; 76…third piezoelectric body; 77…third piezoelectric body; 78…third piezoelectric body; 79…third piezoelectric body; 80…third piezoelectric body; 81…third piezoelectric body; 82…first electrode; 83…second electrode; 84…third piezoelectric body; 85…third piezoelectric body; 86…third piezoelectric body; 2…the fifth electrode; 63…the sixth electrode; 90…the medium; 100…the liquid ejecting device; 100a…the liquid ejecting device; 121…the first substrate; 122…the second substrate; 131…the first vibration plate; 132…the second vibration plate; 141…the filter; 242…the conveying body; 244…the conveying belt; 501…the first portion; 502…the second portion; D3…the thickness; D5…the thickness; H0…the wiring space; H1…the first space; H2…the second space; N…the nozzle; P…the pressure; R…the common ink chamber; R1…the first connecting flow channel; R2…the second connecting flow channel; R3…the third connecting flow channel; S1…the pressure chamber; S2…the absorption chamber; V2…the voltage; V3…the voltage; Vx…the predetermined voltage; a…the imaginary surface.

Claims

1. A liquid ejection head, characterized in that: have: a nozzle substrate provided with a nozzle for ejecting liquid; a pressure chamber substrate having a pressure chamber and an absorption chamber, wherein the pressure chamber applies pressure to the liquid for ejecting the liquid from the nozzle, and the absorption chamber is adjacent to the pressure chamber and absorbs vibration of the liquid generated when pressure is applied to the liquid in the pressure chamber; a first piezoelectric body which is provided corresponding to the pressure chamber and applies pressure to the pressure chamber by applying a voltage; a second piezoelectric body, which is arranged corresponding to the absorption chamber; A pressure acquisition unit acquires the pressure of the absorption chamber based on the voltage across 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 body based on the voltage across both ends of the second piezoelectric body, and acquires the pressure of the absorption chamber based on the capacitance.

3. The liquid ejection head according to claim 2, wherein: Also features: a third piezoelectric body connected in series with the second piezoelectric body, wherein the electrostatic capacitance of the third piezoelectric body is known; a voltage applying unit for applying a predetermined voltage to the second piezoelectric body and the third piezoelectric body, The pressure acquisition unit acquires the electrostatic capacitance of the second piezoelectric body based on the voltage across the second piezoelectric body when the predetermined voltage is applied by the voltage applying unit, the voltage across the third piezoelectric body when the predetermined voltage is applied by the voltage applying unit, and the electrostatic capacitance of the third piezoelectric body, and acquires the pressure of the absorption chamber based on the electrostatic capacitance.

4. The liquid ejection head according to claim 2, wherein: The device further includes a driving circuit for applying a driving voltage, the voltage of which changes with time, to the first piezoelectric body.

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

6. 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 absorption chamber commonly connected to the plurality of pressure chambers.

7. The liquid ejection head according to claim 6, wherein: Further having: a first vibration plate that vibrates when a voltage is applied to the first piezoelectric body and applies pressure to the pressure chamber; The second vibration plate is driven by the pressure applied from the absorption chamber, and applies pressure to the second piezoelectric body.

8. The liquid ejection head according to claim 7, wherein: The first vibration plate and the second vibration plate are not separated but are formed using one continuous member.

9. The liquid ejection head according to claim 7, wherein: Further having: a first electrode provided in common with respect to the plurality of pressure chambers and located on one side in a vertical direction relative to the first piezoelectric body; a second electrode provided separately from the plurality of pressure chambers and located on the other side in the up-down direction than the first piezoelectric body; a third electrode provided relative to the absorption chamber and located at the one side in the up-down direction relative to the second piezoelectric body; The fourth electrode is provided with respect to the absorption chamber and is located on the other side in the up-down direction relative to the second piezoelectric body.

10. The liquid ejection head according to claim 9, wherein: The one side is the upper side of the first piezoelectric body, The other side is a lower side of the first piezoelectric body.

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

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

13. The liquid ejection head according to claim 11, wherein The fourth electrode is configured to have a corrugated shape that is sequentially folded while extending along the second direction.

14. A liquid ejection device, characterized in that: It has a liquid ejection head and a pressure acquisition unit, wherein: The liquid ejection head comprises: a nozzle substrate provided with a nozzle for ejecting liquid; a pressure chamber substrate having a pressure chamber and an absorption chamber, wherein the pressure chamber applies pressure to the liquid for ejecting the liquid from the nozzle, and the absorption chamber is adjacent to the pressure chamber and absorbs vibration of the liquid generated when the pressure is applied to the liquid in the pressure chamber; a first piezoelectric body which is provided corresponding to the pressure chamber and applies pressure to the pressure chamber by applying a voltage; a second piezoelectric body, which is arranged corresponding to the absorption chamber, The pressure acquisition unit acquires the pressure of the absorption chamber based on the voltage across the second piezoelectric body.

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