Liquid discharge apparatus and liquid discharge unit

Abstract

The present application relates to a liquid ejecting apparatus and a liquid ejecting unit, and improves the stability of the operation of the liquid ejecting apparatus. A liquid ejecting apparatus includes: an ejecting section that ejects a liquid to a medium by being supplied with a drive signal; a first switching circuit that switches whether or not the drive signal is supplied to the ejecting section; and a power supply circuit that is input with a first power voltage signal and outputs a second power voltage signal to the first switching circuit, the power supply circuit having: a conversion circuit that outputs a pulse signal corresponding to the first power voltage signal; and a smoothing circuit that includes a capacitor and outputs the second power voltage signal that is smoothed with respect to the pulse signal, the capacitor having: an anode foil, a cathode foil, and an oxide film formed on surfaces thereof; a separator disposed between the anode foil and the cathode foil; and an electrolyte present in a gap portion between the anode foil and the cathode foil other than the separator, the electrolyte including: a solid electrolyte phase and a liquid substance phase.

Description

Technical Field

[0001] This invention relates to a liquid ejection device and a liquid ejection unit. Background Technology

[0002] Patent Document 1 discloses a liquid ejection device that forms an image on a medium by ejecting liquid. The device includes a power supply circuit that converts an input power supply voltage into a voltage signal representing the required voltage value used in various parts of the liquid ejection device. In the power supply circuit of such a liquid ejection device, switching power supply circuits are widely used from the viewpoint of reducing the power consumption of the liquid ejection device.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2024-052282

[0004] However, in liquid ejection devices that use a switching power supply as the power circuit, from the viewpoint of improving the stability of the operation of the liquid ejection device, the technology described in Patent Document 1 alone is insufficient, and there is room for improvement. Summary of the Invention

[0005] One embodiment of the liquid ejection device according to the present invention comprises: Conveying section, conveying medium; The ejector section ejects liquid into the medium by being supplied with a drive signal; A first switching circuit switches whether to supply the drive signal to the ejector section; and The power supply circuit receives a first power supply voltage signal as input and outputs a second power supply voltage signal to the first switching circuit. The power supply circuit has the following features: The conversion circuit outputs a pulse signal corresponding to the first power supply voltage signal; and The smoothing circuit includes a capacitor and outputs a second power supply voltage signal after smoothing the pulse signal. The capacitor comprises: an anode foil and a cathode foil, on which an oxide film is formed; a separator disposed between the anode foil and the cathode foil; and an electrolyte present in the voids between the anode foil and the cathode foil, excluding the separator. The electrolyte comprises: a solid electrolyte phase containing a conductive polymeric compound; and a liquid phase existing in a manner surrounding the solid electrolyte phase and containing a liquid substance.

[0006] One embodiment of the liquid ejection unit according to the present invention comprises: The ejector section ejects liquid into the medium by being supplied with a drive signal; A first switching circuit switches whether to supply the drive signal to the ejector section; and The power supply circuit receives a first power supply voltage signal as input and outputs a second power supply voltage signal to the first switching circuit. The power supply circuit has the following features: The conversion circuit outputs a pulse signal corresponding to the first power supply voltage signal; and The smoothing circuit includes a capacitor and outputs a second power supply voltage signal after smoothing the pulse signal. The capacitor comprises: an anode foil and a cathode foil, on which an oxide film is formed; a separator disposed between the anode foil and the cathode foil; and an electrolyte present in the voids between the anode foil and the cathode foil, excluding the separator. The electrolyte comprises: a solid electrolyte phase containing a conductive polymeric compound; and a liquid phase existing in a manner surrounding the solid electrolyte phase and containing a liquid substance. Attached Figure Description

[0007] Figure 1 This is a diagram showing the general structure of a liquid ejection device.

[0008] Figure 2 This is a diagram illustrating an example of the functional configuration of the ejection unit.

[0009] Figure 3 This is a diagram showing the general structure of the ejector section.

[0010] Figure 4 This is a diagram illustrating an example of the functional configuration of a printhead.

[0011] Figure 5 This is a diagram showing an example of the structure of switch W.

[0012] Figure 6 This is a diagram illustrating an example of various signals input to a circuit specifying a connection state.

[0013] Figure 7 This is a diagram illustrating an example of the structure of a waveform shaping circuit.

[0014] Figure 8 This is a diagram illustrating an example of the various signals output by the control circuit during the ejection process.

[0015] Figure 9 This is a diagram illustrating an example of the relationship between the individual specified signal Sd[m] and the connection status specified signals Qc[m] and Qs[m] during the execution of the ejection process.

[0016] Figure 10This is a diagram illustrating an example of the various signals input to the supply switching circuit of the print head during the execution of the decision processing.

[0017] Figure 11 This is a diagram illustrating an example of the relationship between the individual specified signal Sd[m] and the connection state specified signals Qc[m] and Qs[m] during the execution of the decision processing.

[0018] Figure 12 This is a diagram illustrating an example of the relationship between the individual specified signal Sd[m] and the connection state specified signals Qf, Q1, Q2 during the execution of the decision process.

[0019] Figure 13 This is a diagram illustrating an example of the acquisition operation of a detection potential signal based on a signal corresponding to the residual vibration generated in the ejection part D[m] of the object under inspection.

[0020] Figure 14 This is a diagram illustrating an example of the functional configuration of a power supply circuit.

[0021] Figure 15 This is a cross-sectional view of a capacitor.

[0022] Figure 16 This is a partial anatomical view of the capacitor elements of a capacitor.

[0023] Figure 17 This is a cross-sectional view used to illustrate the main parts of a capacitor.

[0024] Explanation of reference numerals in the attached figures

[0025] 1: Liquid ejection device; 2: Control unit; 3: Liquid container; 4: Conveying unit; 5: Ejection unit; 6: Power supply unit; 10: Drive module; 15: Wiring board; 17: Connecting component; 20: Ejection module; 21: Supply switching circuit; 22: Recording head; 23: Detection circuit; 25: Print head; 30: Control circuit; 40: Drive circuit; 41: Conveyor motor; 42: Conveyor roller; 50: Power supply circuit; 51: Control circuit; 52: Conversion circuit; 53: Smoothing circuit; 54: Feedback circuit; 60: Judgment circuit; 210: Connection status specification circuit; 221: Vibrating plate; 222: Cavity; 223: Nozzle plate; 224: Cavity plate; 225: Liquid reservoir; 226: Ink supply port; 227: Ink intake port; 230: Waveform shaping circuit; 23 1: AD conversion circuit; 521, 522: Transistor; 531: Inductor; 532: Capacitor; 541, 542: Resistor; 550: Capacitor element; 551: Divider; 552: Anode foil; 553: Cathode foil; 554, 555: Oxide film; 556: Electrolyte; 557: Solid electrolyte; 558: Liquid substance; 560: Outer packaging shell; 570: Sealing component; 580, 590: Lead terminals; C1: Capacitor; D: Ejector section; N: Nozzle; OP1, OP2: Operational amplifier; P: Dielectric; PZ: Piezoelectric element; R1~R3, Rf: Resistor; W1, W2, Wc, Wf: Switch; Wiv: Inverter; Wnm, Wpm: Transistor; Ws: Switch; Zd: Lower electrode; Zm: Piezoelectric element; Zu: Upper electrode. Detailed Implementation

[0026] Preferred embodiments of the present invention will now be described using the accompanying drawings. The drawings are provided for ease of explanation. Furthermore, the embodiments described below do not unduly limit the scope of the invention as defined in the claims. Moreover, not all of the structures described below are necessarily essential components of the present invention.

[0027] 1. Structure of the liquid ejection device

[0028] Figure 1This is a diagram showing a schematic structure of the liquid ejection device 1. The liquid ejection device 1 of this embodiment is a so-called line inkjet printer, which ejects ink, as an example of liquid, from a medium P conveyed by a transport unit 4 at desired timings using multiple ejection units 5, forming the desired image on the medium P. Furthermore, the liquid ejection device 1 is not limited to line inkjet printers, but can also be a serial inkjet printer. Moreover, the liquid ejection device 1 is not limited to inkjet printers; it can be a pigment ejection device used in the manufacture of color filters for liquid crystal displays, an electrode material ejection device used in the electrode formation of organic EL displays, FEDs (surface-emitting diodes), etc., a biological organic matter ejection device used in the manufacture of biochips, or a three-dimensional modeling device or printing and dyeing device. Here, in the following description, the direction in which the transport medium P is transported is sometimes referred to as the transport direction, and the width direction of the transported medium P is sometimes referred to as the scanning direction.

[0029] like Figure 1 As shown, the liquid ejection device 1 includes a control unit 2, a liquid container 3, a conveying unit 4, multiple ejection units 5, and a power supply unit 6.

[0030] The power supply unit 6 generates, for example, a constant DC voltage signal (VDC) with a voltage value of 48V based on the AC voltage signal supplied to the liquid dispensing device 1 from a commercial power source or similar source, and outputs it to various parts of the liquid dispensing device 1. This power supply unit 6 is configured to include an AC / DC converter such as a flyback circuit. Furthermore, in addition to the power voltage signal VDC, the power supply unit 6 can also generate one or more DC voltage signals with different values ​​used as power supply voltages in the control unit 2, liquid container 3, and delivery unit 4, and output them to the corresponding structures. In this case, the power supply unit 6 can also include a DC / DC converter in addition to the aforementioned AC / DC converter.

[0031] The control unit 2 includes processing circuits such as a CPU (Central Processing Unit) or FPGA (Field Programmable Gate Array) and storage circuits such as semiconductor memory. Based on image data supplied from an external device such as a host computer (not shown) located outside the liquid ejection device 1, the control unit 2 generates signals that control various elements of the liquid ejection device 1, including various signals such as the transmission control signal Ctrl-T and the image information signal IP, and outputs them to the corresponding structures.

[0032] The liquid container 3 stores ink, as an example of liquid supplied to the ejection unit 5. Specifically, the liquid container 3 stores ink of various colors that are ejected onto the medium P, such as black, cyan, magenta, yellow, red, and gray inks. Such a liquid container 3 can be an ink cartridge, a bag-shaped ink pack formed of a flexible membrane, or an ink canister for refilling ink.

[0033] The conveying unit 4 includes a conveying motor 41 and a conveying roller 42. A conveying control signal Ctrl-T, output from the control unit 2, is input to the conveying unit 4. Furthermore, the conveying motor 41 is driven based on the conveying control signal Ctrl-T, and the conveying roller 42 rotates in tandem with the drive of the conveying motor 41. Through the rotation of the conveying roller 42, the medium P is conveyed along the conveying direction. In other words, the liquid ejection device 1 includes a conveying unit 4 for conveying the medium P.

[0034] Each of the multiple ejection units 5 has a drive module 10 and an ejection module 20. A power supply voltage signal VDC output from a power supply unit 6 and a corresponding image information signal IP output from a control unit 2 are input to each of the multiple ejection units 5, and ink stored in a liquid container 3 is supplied via an ink tube (not shown). The drive module 10 operates using the power supply voltage signal VDC as drive power and controls the operation of the ejection module 20 based on the image information signal IP. Thus, the ejection module 20 ejects the ink supplied from the liquid container 3 at predetermined timings corresponding to the control of the drive module 10.

[0035] In the liquid ejection device 1 of this embodiment, each of the plurality of ejection units 5 has an ejection module 20 arranged and positioned along the scanning direction such that it is at least as wide as the medium P. This constitutes a line print head. Furthermore, each of the plurality of ejection units 5 ejects ink onto the medium P at a timed synchronization with the transport of the medium P. As a result, the ink lands at the desired position on the medium P, forming the desired image on the medium P.

[0036] Here, a specific example of the structure of the ejection unit 5 will be explained. Figure 2 This is a diagram showing an example of the functional configuration of the ejection unit 5.

[0037] As described above, a power supply voltage signal VDC and an image information signal IP are input to the ejection unit 5. Furthermore, the ejection unit 5 is driven by the power supply voltage signal VDC as driving power to form an image corresponding to the image information signal IP on the medium P.

[0038] like Figure 2As shown, the ejection unit 5 includes a drive module 10 and an ejection module 20. The drive module 10 includes a control circuit 30, a drive circuit 40, a power supply circuit 50, and a determination circuit 60, and a wiring board 15 on which the control circuit 30, drive circuit 40, power supply circuit 50, and determination circuit 60 are provided. The ejection module 20 includes a printhead 25. Furthermore, the wiring board 15 of the drive module 10 and the printhead 25 of the ejection module 20 are electrically connected via a connection member 17, which serves as a BtoB connector. Thus, the wiring board 15 of the drive module 10 and the printhead 25 of the ejection module 20 can be communicatively connected. In other words, the printhead 25 and the wiring board 15 are electrically connected via the connection member 17, which serves as a BtoB connector. Here, the connection member 17 is not limited to a BtoB connector; it can be a flexible flat cable or a flexible wiring board, and various connectors including BtoB connectors can be used in conjunction with flexible flat cables or flexible wiring boards.

[0039] In addition, in this embodiment, the case where the ejection module 20 has one printhead 25 is used as an example for explanation, but the ejection module 20 may also have multiple printheads 25.

[0040] A power supply voltage signal VDC is input to the power supply circuit 50. The power supply circuit 50 generates and outputs a DC voltage signal, such as a constant 42V DC voltage signal VHV, by stepping down the voltage value of the power supply voltage signal VDC. This power supply circuit 50 is a DC / DC converter that steps down the power supply voltage signal VDC and outputs the power supply voltage signal VHV, and is composed of a DC / DC converter including a switching power supply circuit. Further details of the structure of the power supply circuit 50 will be described later.

[0041] Here, the power supply circuit 50 can also be structured such that, in addition to the power supply voltage signal VHV, it can output multiple DC voltage signals with voltage values ​​different from the power supply voltage signal VHV, such as a DC voltage signal with a voltage value of 5V or a DC voltage signal with a voltage value of 3.3V. In this case, the power supply circuit 50 may also include one or more DC / DC converters that step down the voltage value of the power supply voltage signal VHV. Furthermore, the power supply circuit 50 can also be structured such that an AC voltage signal, such as a commercial power supply, is input instead of the power supply voltage signal VDC. That is, the power supply circuit 50 can also be structured such that it includes an AC / DC converter as a switching power supply circuit, inputs an AC voltage signal, such as a commercial power supply, to the AC / DC converter, and outputs a power supply voltage signal VHV as a DC voltage signal.

[0042] The control circuit 30 controls the operation of each structure of the liquid ejection device 1, including the drive circuit 40, the determination circuit 60, and the print head 25. The control circuit 30 is configured with one or more CPUs (Central Processing Units). Alternatively, the control circuit 30 may replace the CPU or, based on the CPU, include programmable logic devices such as FPGAs (Field Programmable Gate Arrays), and may further include storage circuitry. Furthermore, the control circuit 30 generates and outputs signals such as clock signal CL, print data signal SI, latch signal LAT, change signal CH, period specification signal Tsig, and drive waveform specification signal dCom, based on the input image information signal IP, to control the operation of each part of the ejection unit 5. Additionally, the control circuit 30 may further output a control power supply voltage signal VHV from the power supply circuit 50.

[0043] The drive waveform specification signal dCom output by the control circuit 30 is input to the drive circuit 40. Additionally, the power supply voltage signal VHV output by the power supply circuit 50 is also input to the drive circuit 40. The drive circuit 40 generates and outputs a drive signal Com that drives the plurality of ejection sections D of the printhead 25 (described later). Specifically, the drive waveform specification signal dCom is a digital signal that defines the signal waveform of the drive signal Com output by the drive circuit 40. The drive circuit 40 converts the input drive waveform specification signal dCom into an analog signal using a DA conversion circuit (not shown), and performs D-level amplification on the converted analog signal according to the power supply voltage signal VHV, thereby generating and outputting the drive signal Com, which is an amplified version of the signal waveform specified by the drive waveform specification signal dCom. Alternatively, the drive circuit 40 can also perform B-level or AB-level amplification on the signal waveform specified by the drive waveform specification signal dCom according to the power supply voltage signal VHV, thereby generating and outputting the drive signal Com.

[0044] The clock signal CL, print data signal SI, latch signal LAT, change signal CH, and period specification signal Tsig output by control circuit 30, the drive signal Com output by drive circuit 40, and the power supply voltage signal VHV output by power supply circuit 50 are input to printhead 25. Print data signal SI is a signal transmitted synchronously with clock signal CL. It is a digital signal that specifies the type of operation of the multiple ejector heads D within each period defined by latch signal LAT, change signal CH, and period specification signal Tsig. Specifically, print data signal SI contains information specifying whether to supply drive signal Com corresponding to each of the multiple ejector heads D within each period defined by latch signal LAT, change signal CH, and period specification signal Tsig, thereby individually specifying the operation of the corresponding ejector head D.

[0045] The printhead 25 includes a supply switching circuit 21, a recording head 22, and a detection circuit 23. Furthermore, the recording head 22 has multiple ejection sections D. In the following description, the recording head 22 will be described as having M ejection sections D. Moreover, when the M ejection sections D of the recording head 22 are described individually, they are referred to as ejection sections D[1] to D[M]. In this case, when the m-th ejection section D of the M ejection sections D of the recording head 22 is described, it is sometimes referred to as ejection section D[m]. Here, M is a natural number satisfying "M≥1", and m is any natural number satisfying "1≤m≤M". Furthermore, in the following description, when the components or signals of the liquid ejection device 1 correspond to the ejection section D[m] of the M ejection sections D, the reference numerals representing these components or signals are sometimes marked with the subscript [m]. That is, the printhead 25 includes multiple ejection sections D and a supply switching circuit 21.

[0046] Clock signal CL, print data signal SI, latch signal LAT, change signal CH, period specification signal Tsig, drive signal Com, and power supply voltage signal VHV are input to the supply switching circuit 21 of the printhead 25. In each of the timings specified by the latch signal LAT, change signal CH, and period specification signal Tsig, the supply switching circuit 21 switches whether to supply the drive signal Com as the supply drive signal Vin to the corresponding ejection section D based on the print data signal SI. This supply drive signal Vin is then supplied to the piezoelectric element PZ (described later) of the ejection section D, driving the piezoelectric element PZ to eject an amount of ink from the ejection section D corresponding to the driving amount of the piezoelectric element PZ.

[0047] Furthermore, in each of the timings specified by the latch signal LAT, the change signal CH, and the period specification signal Tsig, the supply switching circuit 21 acquires a signal corresponding to the residual vibration generated in the ejection section D of the inspected object based on the printing data signal SI, and switches whether to supply it to the detection circuit 23 as a detection potential signal VX.

[0048] The detection circuit 23 generates a detection signal SK based on the detection potential signal VX supplied via the supply switching circuit 21 and outputs it from the printhead 25. Specifically, the detection circuit 23 amplifies the input detection potential signal VX and, after removing noise components, converts the signal into a digital signal, thereby generating the detection signal SK and outputting it from the printhead 25.

[0049] The detection signal SK output from the printhead 25 is input to the determination circuit 60. Based on the input detection signal SK, the determination circuit 60 determines whether the ink ejection state in the ejection section D of the object under inspection is normal, i.e., whether the ejection section D of the object under inspection is in a normal ejection state. Specifically, the determination circuit 60 reads predetermined determination threshold information and correction value information from a storage circuit (not shown), including a non-volatile memory such as ROM (Read Only Memory) or flash memory. The determination circuit 60 corrects the input detection signal SK according to the read correction value information and compares the corrected signal with the predetermined determination threshold information. Then, based on the comparison result, the determination circuit 60 determines whether an ejection abnormality has occurred in the ejection section D of the object under inspection, i.e., whether the ejection section D of the object under inspection is in a normal ejection state. Then, the determination circuit 60 generates a status determination signal JH representing the determination result and outputs it to the control circuit 30. In the following explanation, the determination of whether an abnormality has occurred in the ejection section D of the object under inspection, that is, whether the ejection section D of the object under inspection is in a normal ejection state in the vertical direction, is sometimes referred to as determining the state of the ejection section D of the object under inspection.

[0050] Here, "ejection anomaly" refers to an abnormal state in which the ink ejection from the ejection section D of the object under inspection is not accurately ejected; it is a general term for the state in which ink cannot be accurately ejected from the ejection section D of the object under inspection. Such ejection anomalies include, for example, the state in which ink cannot be ejected from the ejection section D, the state in which an amount of ink different from the amount of ink ejected by the drive signal Com is ejected from the ejection section D, and the state in which ink is ejected from the ejection section D at a speed different from the ink ejection speed specified by the drive signal Com.

[0051] As described above, when performing the ink ejection process to form an image corresponding to the image information signal IP on the medium P by ejecting ink, the control circuit 30 generates a printing data signal SI, etc., to control the print head 25 to eject ink based on the image information signal IP, and outputs it to the print head 25. It also generates a drive waveform specification signal dCom to control the drive circuit 40 to output a drive signal Com to drive the ejection section D in the manner of ink ejection, and outputs it to the drive circuit 40. The drive circuit 40 generates a drive signal Com corresponding to the input drive waveform specification signal dCom and outputs it to the print head 25. Thus, the presence or absence of ink ejection from each of the multiple ejection sections D, the amount of ink ejected, and the ink ejection timing are controlled. As a result, an image corresponding to the image information signal IP is formed on the medium P.

[0052] Furthermore, during the determination process for the state of the ejection section D, the control circuit 30 generates a printing data signal SI, etc., for determining the state of the ejection section D of the object under inspection, and outputs it to the print head 25. It also generates a drive waveform specification signal dCom for controlling the drive circuit 40 to output a drive signal Com for determining the state of the ejection section D, and outputs it to the drive circuit 40. The drive circuit 40 generates a drive signal Com corresponding to the input drive waveform specification signal dCom and outputs it to the print head 25. Consequently, the supply switching circuit 21 outputs a signal corresponding to the residual vibration generated in the ejection section D of the object under inspection as a detection potential signal VX to the detection circuit 23. The detection circuit 23 acquires the input detection potential signal VX, generates a detection signal SK corresponding to the acquired detection potential signal VX, and outputs it to the determination circuit 60. Then, based on the input detection signal SK, the determination circuit 60 determines whether the ink ejection state in the ejection section D of the object under inspection is normal, i.e., whether the ejection section D of the object under inspection is in a normal ejection state, and outputs a state determination signal JH corresponding to the determination result to the control circuit 30. Therefore, the control circuit 30 can acquire the state of the ejection portion D of the object under inspection, and correct various output signals based on the acquired state of the ejection portion D of the object under inspection. As a result, the quality of the image formed on the medium is improved.

[0053] As described above, in the liquid ejection device 1 of this embodiment, the ejection unit 5 performs various processes, including: ejection processing, forming an image corresponding to the image information signal IP on a medium; and determination processing, determining the state of the ejection section D that ejects ink to the medium.

[0054] Furthermore, in the liquid ejection device 1, the control circuit 30 and the determination circuit 60 of the drive module 10 of the ejection unit 5 can also be mounted in a common semiconductor device. In this case, part or all of the drive circuit 40 and the delivery unit 4 can also be mounted in the semiconductor device. In addition, the supply switching circuit 21 and the detection circuit 23 of the print head 25 of the ejection module 20 can also be mounted in a common semiconductor device.

[0055] Here, an example of the structure of the ejection section D that ejects ink to the medium P will be described. Figure 3 This is a diagram showing a schematic structure of an ejector section D. (See diagram below.) Figure 3 As shown, the ejection section D includes a piezoelectric element PZ, a cavity 222 filled with ink, a nozzle N communicating with the cavity 222, and a vibrating plate 221. Furthermore, the ejection section D supplies a drive signal Vin to the piezoelectric element PZ, which is then driven to eject the ink stored inside the cavity 222 from the nozzle N.

[0056] The cavity 222 is a space defined by the cavity plate 224, the nozzle plate 223 on which the nozzle N is formed, and the vibrating plate 221. The cavity 222 is connected to the reservoir 225 via the ink supply port 226, and the reservoir 225 is connected to the liquid container 3 corresponding to the ejection section D via the ink intake port 227. Thus, ink is supplied from the corresponding liquid container 3 into the cavity 222 via the ink intake port 227, the reservoir 225, and the ink supply port 226. Therefore, the cavity 222 is filled with ink supplied from the corresponding liquid container 3.

[0057] The piezoelectric element PZ has an upper electrode Zu, a lower electrode Zd, and a piezoelectric body Zm. The piezoelectric body Zm is located between the upper electrode Zu and the lower electrode Zd. A supply drive signal Vin, output from the supply switching circuit 21, is supplied to the upper electrode Zu. Furthermore, a reference voltage signal Vbs, transmitted in the wiring Lb, is supplied to the lower electrode Zd. The piezoelectric body Zm operates according to the potential difference between the upper electrode Zu and the lower electrode Zd, i.e., the potential difference between the voltage value of the supply drive signal Vin supplied to the upper electrode Zu and the voltage value of the reference voltage signal Vbs supplied to the lower electrode Zd. Figure 3 The piezoelectric element PZ is displaced in the vertical direction. That is, the piezoelectric element PZ is driven according to the potential difference between the voltage value of the supplied drive signal Vin and the voltage value of the reference voltage signal Vbs. Here, the reference voltage signal Vbs supplied to the lower electrode Zd is a signal that serves as the reference potential for driving the piezoelectric element PZ, and is a signal with a constant potential such as 5.5V or 6V, or ground potential.

[0058] The lower electrode Zd is engaged with the vibrating plate 221. Therefore, the piezoelectric element PZ is driven by supplying a drive signal Vin to cause the piezoelectric element PZ to vibrate. Figure 3 When the vertical displacement is shown, the vibrating plate 221 also... Figure 3 The displacement is shown in the vertical direction. Due to the displacement of the vibrating plate 221, the internal volume and internal pressure of the cavity 222 change. Furthermore, based on the change in the internal volume and internal pressure of the cavity 222, ink filling the cavity 222 is ejected from the nozzle N. That is, an amount of ink corresponding to the driving amount of the piezoelectric element PZ is ejected from the nozzle N of the ejection section D. In other words, the piezoelectric element PZ causes an amount of ink, corresponding to the displacement generated by the supply drive signal Vin corresponding to the drive signal Com, to be ejected from the ejection section D. In other words, the print head 25 of the liquid ejection device 1 of this embodiment includes an ejection section D that ejects liquid by driving the piezoelectric element PZ.

[0059] 2. The structure and operation of the print head

[0060] 2.1 Structure of the print head

[0061] Next, the functional composition of the printhead 25 will be explained. Figure 4 This diagram illustrates an example of the functional configuration of the printhead 25. As described above, the printhead 25 includes a supply switching circuit 21, a recording head 22, and a detection circuit 23. Furthermore, in... Figure 4 The diagram illustrates the wiring Lc for transmitting the drive signal Com, the wiring Lb for transmitting the reference voltage signal Vbs, and the wiring Ls for transmitting the detection potential signal VX to the detection circuit 23 in the printhead 25.

[0062] The supply switching circuit 21 includes switches Wc[1] to Wc[M], switches Ws[1] to Ws[M], switch Wf, resistor Rf, and connection state specifying circuit 210. Switches Wc[1] to Wc[M] and switches Ws[1] to Ws[M] are provided in the supply switching circuit 21 corresponding to the ejector sections D[1] to D[M]. Specifically, in the supply switching circuit 21, switches Wc[m] and Ws[m] are provided corresponding to the ejector section D[m].

[0063] The power supply voltage signal VHV, clock signal CL, print data signal SI, latch signal LAT, change signal CH, and period specification signal Tsig are input to the print head 25. The power supply voltage signal VHV, clock signal CL, print data signal SI, latch signal LAT, change signal CH, and period specification signal Tsig are input to the connection status specification circuit 210.

[0064] In each of the periods specified by the input latch signal LAT, change signal CH, and period specification signal Tsig, the connection state specifying circuit 210 generates a signal specifying the conduction state of switches Wc[1] to Wc[M], switches Ws[1] to Ws[M], and switch Wf, based on the printed data signal SI transmitted synchronously with the clock signal CL. Subsequently, the connection state specifying circuit 210 outputs connection state specifying signals Qc[1] to Qc[M] by shifting the signal level of the conduction state of the specified switches Wc[1] to Wc[M] to a high-amplitude logic signal of the power supply voltage signal VHV; outputs connection state specifying signals Qs[1] to Qs[M] by shifting the signal level of the conduction state of the specified switches Ws[1] to Ws[M] to a high-amplitude logic signal of the power supply voltage signal VHV; and outputs connection state specifying signal Qf by shifting the signal level of the conduction state of the specified switch Wf to a high-amplitude logic signal of the power supply voltage signal VHV. That is, the connection state specification circuit 210 generates and outputs connection state specification signals Qc[1]~Qc[M], Qs[1]~Qs[M], and Qf, with H level being the power supply voltage signal VHV and L level being the ground potential.

[0065] Furthermore, the connection state specifying signals Qc[1] to Qc[M] output by the connection state specifying circuit 210 are input to the control terminals of switches Wc[1] to Wc[M], the connection state specifying signals Qs[1] to Qs[M] output by the connection state specifying circuit 210 are input to the control terminals of switches Ws[1] to Ws[M], and the connection state specifying signal Qf output by the connection state specifying circuit 210 is input to the control terminal of switch Wf. Thus, the conduction states of switches Wc[1] to Wc[M], Ws[1] to Ws[M], and Wf are controlled.

[0066] Such a connection state designation circuit 210 is configured, for example, to include: a register that holds a print data signal SI that is transmitted synchronously with the clock signal CL, corresponding to the ejector parts D[1] to D[M]; a decoder that generates a signal specifying the conduction state of switches Wc[1] to Wc[M], Ws[1] to Ws[M], and Wf by decoding the print data signal SI held by the register; and a level shifting circuit that outputs connection state designation signals Qc[1] to Qc[M], Qs[1] to Qs[M], and Qf, etc., of a high-amplitude logic signal that shifts the logic level of the signal generated by the decoder to the voltage value of the power supply voltage signal VHV.

[0067] One end of switch Wc[m] from switches Wc[1] to Wc[M] is electrically connected to wiring Lc, and the other end is electrically connected to the upper electrode Zu[m] of the piezoelectric element PZ[m] contained in the ejector section D[m]. The connection state specification signal Qc[m] from the connection state specification signals Qc[1] to Qc[M] is input to the control terminal of switch Wc[m]. Switch Wc[m] switches the conduction state between one end and the other end according to the logic level of the connection state specification signal Qc[m] input to the control terminal. That is, switch Wc[m] switches the connection state between wiring Lc and upper electrode Zu[m] according to the logic level of the connection state specification signal Qc[m] input to the control terminal. Thus, switch Wc[m] switches whether to supply the drive signal Com transmitted in wiring Lc as the supply drive signal Vin[m] to the upper electrode Zu[m] of ejector section D[m] according to the connection state specification signal Qc[m].

[0068] One end of switch Ws[m] from switches Ws[1] to Ws[M] is electrically connected to wiring Ls, and the other end is electrically connected to the upper electrode Zu[m] of the piezoelectric element PZ[m] contained in the ejector section D[m]. The connection state specification signal Qs[m] from the connection state specification signals Qs[1] to Qs[M] is input to the control terminal of switch Ws[m]. Switch Ws[m] switches the conduction state between one end and the other end according to the logic level of the connection state specification signal Qs[m] input to the control terminal. That is, switch Ws[m] switches the connection state between wiring Ls and the upper electrode Zu[m] according to the logic level of the connection state specification signal Qs[m] input to the control terminal. Thus, switch Ws[m] switches whether to supply the signal generated in the upper electrode Zu[m] of the piezoelectric element PZ[m] based on the residual vibration generated in the ejector section D[m] to wiring Ls according to the connection state specification signal Qs[m].

[0069] One end of switch Wf is electrically connected to wiring Lc, and the other end is electrically connected to one end of resistor Rf. Furthermore, the other end of resistor Rf is electrically connected to wiring Ls. That is, one end of switch Wf is electrically connected to wiring Lc, and the other end is electrically connected to wiring Ls via resistor Rf. A connection state specification signal Qf is input to the control terminal of switch Wf. Switch Wf switches the conduction state between one end and the other end according to the logic level of the connection state specification signal Qf input to the control terminal. In other words, switch Wf switches the connection state of wiring Lc and wiring Ls according to the logic level of the connection state specification signal Qf input to the control terminal.

[0070] That is, the supply switching circuit 21 has: switches Ws[1] to Ws[M], which switch whether to supply the detection potential signal VX to the detection circuit 23; and switches Wc[1] to Wc[M], which switch whether to supply the drive signal Com to the ejection section D[1] to D[M]. Moreover, the switches Ws[1] to Ws[M] switch whether to supply the detection potential signal VX to the detection circuit 23 based on the connection state specification signal Qs[1] to Qs[M] corresponding to the power supply voltage signal VHV, and the switches Wc[1] to Wc[M] switch whether to supply the drive signal Com to the piezoelectric element PZ[1] to PZ[m] based on the connection state specification signal Qc[1] to Qc[M] corresponding to the power supply voltage signal VHV. That is, the power supply voltage signal VHV output by the power supply circuit 50 is supplied to the switches Wc[1] to Wc[M] and Ws[1] to Ws[M].

[0071] Each of such switches Wc[1]~Wc[M] and Ws[1]~Ws[M] can be constructed, for example, by a transmission gate. Here, an example of the structure of the transmission gate that constitutes the switches Wc[1]~Wc[M] and Ws[1]~Ws[M] will be described. In addition, the switches Wc[1]~Wc[M] and Ws[1]~Ws[M] are identical in structure, differing only in the input signal and the output signal. Therefore, in the following description, the switches Wc[1]~Wc[M] and Ws[1]~Ws[M] will not be distinguished, and will be referred to simply as switches W. At this time, the following situation shall be explained: one end of switch W is electrically connected to the wiring Lc that transmits the drive signal Com or the wiring Ls that transmits the detection potential signal VX to the detection circuit 23, and the other end of switch W is electrically connected to the upper electrode Zu of the piezoelectric element PZ of the ejector part D[1]~D[M]. The connection state specification signal Q, which is the connection state specification signal Qc[1]~Qc[M] and Qs[1]~Qs[M], is input to the control terminal of switch W.

[0072] Figure 5 This is a diagram illustrating an example of the structure of switch W. (As shown...) Figure 5 As shown, the switch W includes a transistor Wnm, which is an n-channel MOS-FET, a transistor Wpm, which is a p-channel MOS-FET, and an inverter Wiv.

[0073] One end of transistor Wnm is electrically connected to one end of transistor Wpm, and the other end of transistor Wnm is electrically connected to the other end of transistor Wpm. Here, one end of transistor Wnm is equivalent to the drain terminal of switch Wc[1]~Wc[M] and the source terminal of switch Ws[1]~Ws[M]. The other end of transistor Wnm is equivalent to the source terminal of switch Wc[1]~Wc[M] and the drain terminal of switch Ws[1]~Ws[M]. One end of transistor Wpm is equivalent to the source terminal of switch Wc[1]~Wc[M] and the drain terminal of switch Ws[1]~Ws[M]. The other end of transistor Wpm is equivalent to the drain terminal of switch Wc[1]~Wc[M] and the source terminal of switch Ws[1]~Ws[M].

[0074] Furthermore, the connection point where one end of transistor Wnm and one end of transistor Wpm are connected is electrically connected to wiring L, and the connection point where the other ends of transistor Wnm and the other ends of transistor Wpm are connected is electrically connected to the upper electrode Zu of piezoelectric element PZ. That is, the connection point where one end of transistor Wnm and the other end of transistor Wpm are connected is equivalent to one end of switch W, and the connection point where the other ends of transistor Wnm and the other ends of transistor Wpm are connected is equivalent to the other end of switch W.

[0075] Furthermore, a connection state specification signal Q is input to the gate terminal of transistor Wnm, and a signal with the logic level inverted from the connection state specification signal Q is input to the gate terminal of transistor Wpm via inverter Wiiv. That is, the conduction state of transistors Wnm and Wpm is controlled by the connection state specification signal Q based on the power supply voltage signal VHV.

[0076] In addition, a ground potential is supplied to the back gate terminal of transistor Wnm, and a power supply voltage signal VHV is supplied to the back gate terminal of transistor Wpm.

[0077] In the switch W constructed as described above, when a connection state specification signal Q of level H is input, one end of transistor Wnm and the other end of transistor Wpm are controlled to be connected; when a connection state specification signal Q of level L is input, one end of transistor Wnm and the other end of transistor Wpm are controlled to be de-connected. That is, when a connection state specification signal Q of level H is input to the control terminal of switch W, one end of switch W is controlled to be connected; when a connection state specification signal Q of level L is input to the control terminal of switch W, one end of switch W is controlled to be de-connected.

[0078] Alternatively, switch W can input a connection state specification signal Q to the gate terminal of transistor Wpm, and input a signal with the logic level inverted from the connection state specification signal Q to the gate terminal of transistor Wnm via inverter Wiiv. In this case, switch W can also be controlled to be on at one end and the other end when an L-level connection state specification signal Q is input to the control terminal of switch W, and controlled to be off at one end and the other end when an H-level connection state specification signal Q is input to the control terminal of switch W.

[0079] That is, switches Wc[1] to Wc[M] include switching whether to supply the drive signal Com to the piezoelectric element PZ[1] to PZ[M] transistors Wnm and Wpm, and the power supply voltage signal VHV is supplied to the back gate terminal of transistor Wpm. Switches Ws[1] to Ws[M] include switching whether to supply the detection potential signal VX to the detection circuit 23 transistors Wnm and Wpm, and the power supply voltage signal VHV is supplied to the back gate terminal of transistor Wpm.

[0080] Return to Figure 4 During the period specified by the input latch signal LAT, change signal CH, and period specification signal Tsig, the connection status specification circuit 210 generates connection status specification signals Q1 and Q2 based on the printed data signal SI transmitted based on the clock signal CL and outputs them to the detection circuit 23.

[0081] Here, an example of various signals input to the connection state designation circuit 210 will be described. Figure 6 This is a diagram illustrating an example of the various signals input to the connection state specification circuit 210. For example... Figure 6 As shown, the liquid ejection device 1 of this embodiment defines one or more unit periods TP as operating periods, and controls the operation of the drive and detection circuit 23 of the ejection section D[m] in each of the defined unit periods TP.

[0082] Specifically, control circuit 30 generates a latch signal LAT containing a pulse PLL and outputs it to connection state designation circuit 210. For example, control circuit 30 may also generate a latch signal LAT containing a pulse PLL by setting the logic level of the latch signal LAT to H level for a short period based on the timing of the transport position of the medium P transported along the transport direction, and output it to connection state designation circuit 210. Alternatively, control circuit 30 may generate a latch signal LAT containing a pulse PLL by setting the logic level of the latch signal LAT to H level for a short period at predetermined time intervals, and output it to connection state designation circuit 210. The period from the rising edge of the pulse PLL in the latch signal LAT to the rising edge of the next pulse PLL corresponds to the aforementioned unit period TP.

[0083] Furthermore, the control circuit 30 generates a change signal CH containing a pulse PLC and outputs it to the connection state designation circuit 210. For example, the control circuit 30 generates the change signal CH containing a pulse PLC by timing the logic level of the change signal CH to H level for a short period of time after a predetermined time has elapsed from the rising edge of the pulse PLL, and outputs it to the connection state designation circuit 210. The pulse PLC contained in this change signal CH divides the unit period TP into a control period TQ1 and a control period TQ2. Specifically, the change signal CH divides the unit period TP into a control period TQ1, which is the period from the rising edge of the pulse PLL to the rising edge of the pulse PLC, and a control period TQ2, which is the period from the rising edge of the pulse PLC to the rising edge of the pulse PLL. In addition, the number of units that the unit period TP is divided by the change signal CH is not limited to two.

[0084] Furthermore, the control circuit 30 generates a period-specifying signal Tsig containing pulses PLT1 and PLT2, and outputs it to the connection state specifying circuit 210. For example, after a predetermined time elapsed from the rising edge of pulse PLL, the control circuit 30 sets the logic level of the period-specifying signal Tsig to H level, and then sets the logic level of the period-specifying signal Tsig to L level, thereby generating pulse PLT1 and outputting it to the connection state specifying circuit 210. After generating pulse PLT1, after a predetermined time elapsed, the control circuit 30 sets the logic level of the period-specifying signal Tsig to H level, and then sets the logic level of the period-specifying signal Tsig to L level, thereby generating pulse PLT2 and outputting it to the connection state specifying circuit 210. The pulses PLT1 and PLT2 contained in the period-specifying signal Tsig divide the unit period TP into control periods TT1 to TT5. Specifically, the period specification signal Tsig divides the unit period TP into control periods TT1 (from the rising edge of pulse PLL to the rising edge of pulse PLT1), TT2 (from the rising edge of pulse PLT1 to the falling edge of pulse PLT1), TT3 (from the falling edge of pulse PLT1 to the rising edge of pulse PLT2), TT4 (from the rising edge of pulse PLT2 to the falling edge of pulse PLT2), and TT5 (from the falling edge of pulse PLT2 to the rising edge of pulse PLL). Furthermore, the number of periods TP divided by the period specification signal Tsig is not limited to five.

[0085] Furthermore, the control circuit 30 generates a printing data signal SI that serially contains individually specified signals Sd[1] to Sd[M], and outputs it to the connection state specifying circuit 210. The individually specified signals Sd[1] to Sd[M] are signals that each contain 3 bits of information, specifying the driving mode of each of the ejector sections D[1] to D[M]. Here, in the following description, the 3 bits of information contained in the individually specified signal Sd[m] are referred to as bits S1, S2, and S3, and are sometimes expressed as individually specified signal Sd[m] = [S1, S2, S3]. Furthermore, in the following description, when the bits S1, S2, and S3 contained in the individually specified signal Sd[m] can be either "1" or "0", the term "1" is sometimes used. To express it as "".

[0086] Specifically, before the unit period TP becomes the controlled object, the control circuit 30 generates a printing data signal SI containing individual specified signals Sd[1] to Sd[M] and outputs it to the connection state specifying circuit 210. The individual specified signals Sd[1] to Sd[M] specify the driving mode of the ejector parts D[1] to D[M] in the unit period TP that becomes the controlled object and the operation of the detection circuit 23. In the connection state specifying circuit 210, the printing data signal SI is maintained in a register (not shown) with the states corresponding to the individual specified signals Sd[1] to Sd[M] and the ejector parts D[1] to D[M] respectively. Furthermore, by making the unit period TP the object of control, the connection state specifying circuit 210 latches the 3 bits of information contained in each of the individually specified signals Sd[1] to Sd[M] held together, and decodes the latched 3 bits of information. Thus, in each of the control periods TQ1 and TQ2 or each of the control periods TT1 to TT5 in the unit period TP that is the object of control, connection state specifying signals Qc[1] to Qc[M], Qs[1] to Qs[M], Qf, Q1, and Q2 with logic levels corresponding to the decoded content are generated and output to the control terminals of the corresponding switches Wc[1] to Wc[M], Ws[1] to Ws[M], Wf, W1, and W2.

[0087] Therefore, the conduction state of each of the switches Wc[1] to Wc[M], Ws[1] to Ws[M], Wf, W1, and W2 in each of the control periods TQ1 and TQ2 or in each of the control periods TT1 to TT5 is controlled. As a result, the driving mode of the ejector parts D[1] to D[M] in each of the control periods TQ1 and TQ2 or in each of the control periods TT1 to TT5 and the operation of the detection circuit 23 are controlled.

[0088] Return to Figure 4The detection circuit 23 receives the detection potential signal VX transmitted in the wiring Ls and the connection status specifying signals Q1 and Q2 output by the connection status specifying circuit 210. Furthermore, the detection circuit 23 includes a waveform shaping circuit 230 and an AD conversion circuit 231. The waveform shaping circuit 230 acquires the detection potential signal VX based on the connection status specifying signals Q1 and Q2. Then, the waveform shaping circuit 230 removes noise from the acquired detection potential signal VX and amplifies it, thereby shaping the signal waveform of the detection potential signal VX and outputting it as the detection signal aSK. The AD conversion circuit 231 converts the analog signal detection signal aSK output by the waveform shaping circuit 230 into a digital signal and outputs it as the detection signal SK. This detection signal SK is output from the detection circuit 23 and the printhead 25. That is, the detection circuit 23 converts the signal corresponding to the residual vibration generated in the ejection section D into a digital signal and outputs it as the detection signal SK.

[0089] Here, an example of the structure of the waveform shaping circuit 230 of the detection circuit 23 will be described. Figure 7 This is a diagram illustrating an example of the structure of the waveform shaping circuit 230. (See diagram for example.) Figure 7 As shown, the waveform shaping circuit 230 includes a capacitor C1, operational amplifiers OP1 and OP2, switches W1 and W2, and resistors R1 to R3.

[0090] A detection potential signal VX, supplied by the switching circuit 21, is input to one end of capacitor C1. The other end of capacitor C1 is electrically connected to one end of resistor R1 and one end of switch W1. A fixed analog ground AG, at a constant potential, is supplied to the other end of resistor R1 and switch W1. That is, resistor R1 and switch W1 are connected in parallel. A connection state specification signal Q1 is input to the control terminal of switch W1. When the connection state specification signal Q1 at a high level is input to the control terminal, one end of switch W1 is connected to the other end; when the connection state specification signal Q1 at a low level is input to the control terminal, one end of switch W1 is not connected to the other end. That is, switch W1 switches the conduction state of one end of resistor R1 and analog ground AG. The capacitor C1, resistor R1, and switch W1 configured as described above function as a high-pass filter, extracting a predetermined high-frequency component signal from the detection potential signal VX input during the period when switch W1 is controlled to be non-conducting and outputting it. Here, switch W1 may, for example, be... Figure 5 The transmission gate configuration is shown. Furthermore, the simulated ground AG can be, for example, the center potential of the power supply potential supplied to the high-potential side and the low-potential side of the printhead 25, or it can be the ground potential of the printhead 25.

[0091] The positive input terminal of operational amplifier OP1 is electrically connected to the connection point of the other end of capacitor C1, one end of resistor R1, and one end of switch W1. That is, the signal output from the high-pass filter formed by capacitor C1, resistor R1, and switch W1 is input to the positive input terminal of operational amplifier OP1. The negative input terminal of operational amplifier OP1 is electrically connected to the connection point of one end of resistor R2 and one end of resistor R3. The output terminal of operational amplifier OP1 is electrically connected to the other end of resistor R2. Furthermore, analog ground AG is supplied to the other end of resistor R3. In other words, operational amplifier OP1 and resistors R2 and R3 function as a non-inverting amplifier circuit, which amplifies the signal input to the positive input terminal of operational amplifier OP1 based on the resistance values ​​of resistors R2 and R3, and outputs it from the output terminal of operational amplifier OP1. Here, the non-inverting amplifier circuit consisting of operational amplifier OP1 and resistors R2 and R3 can also be configured as follows: after superimposing a predetermined offset voltage on the signal output by the high-pass filter consisting of capacitor C1, resistor R1 and switch W1, the amplified signal is output.

[0092] The positive input terminal of operational amplifier OP2 is electrically connected to the output terminal of operational amplifier OP1. That is, the signal output from the non-inverting amplifier circuit consisting of operational amplifier OP1 and resistors R2 and R3 is input to the positive input terminal of operational amplifier OP2. The negative input terminal of operational amplifier OP2 is electrically connected to its output terminal. That is, operational amplifier OP2 constitutes a voltage output circuit. Therefore, operational amplifier OP2 converts the impedance of the signal output from the non-inverting amplifier circuit consisting of operational amplifier OP1 and resistors R2 and R3 and outputs it.

[0093] One end of switch W2 is electrically connected to the output terminal of operational amplifier OP2. The signal from the other end of switch W2 is output as a detection signal aSK from waveform shaping circuit 230. Furthermore, a connection status specification signal Q2 is input to the control terminal of switch W2. When a high-level connection status specification signal Q2 is input to the control terminal, one end of switch W2 is connected to the other; when a low-level connection status specification signal Q2 is input to the control terminal, one end is not connected to the other. Switch W2 toggles whether to output the signal output from operational amplifier OP2 as the detection signal aSK from waveform shaping circuit 230 based on the logic level of the connection status specification signal Q2 input to the control terminal.

[0094] As described above, the waveform shaping circuit 230 removes noise components from the detected potential signal VX using a high-pass filter consisting of capacitor C1, resistor R1, and switch W1. The noise-removed signal is then amplified by a non-inverting amplifier circuit consisting of operational amplifier OP1 and resistors R2 and R3. After impedance transformation by a voltage output circuit consisting of operational amplifier OP2, the waveform shaping circuit 230 outputs the detected potential signal aSK. At this time, switches W1 and W2 toggle whether the waveform shaping circuit 230 acquires the detected potential signal VX and outputs it as the detected signal aSK.

[0095] Then, the detection signal aSK output by the waveform shaping circuit 230 is input to the AD conversion circuit 231. The AD conversion circuit 231 converts the detection signal aSK into a digital signal. Then, the digital signal converted by the AD conversion circuit 231 is output as the detection signal SK from the detection circuit 23 and the print head 25.

[0096] In the printhead 25 of this embodiment, configured as described above, the supply switching circuit 21 controls the conduction state of the switch Wc[m] based on the print data signal SI transmitted based on the clock signal CL during each of the control periods TQ1, TQ2 or control periods TT1 to TT5, as defined by the latch signal LAT, the change signal CH, and the period specification signal Tsig. This switches whether the drive signal Com transmitted in the wiring Ls is supplied as the supply drive signal Vin[m] to the piezoelectric element PZ[m] of the ejector section D[m]. Thus, the driving mode of the ejector section D[m] is controlled.

[0097] Furthermore, in this embodiment, the supply switching circuit 21 of the printhead 25 controls the conduction state of the switch Ws[m] based on the printing data signal SI transmitted based on the clock signal CL during each of the control periods TQ1, TQ2 or control periods TT1 to TT5 specified by the latch signal LAT, the change signal CH, and the period specification signal Tsig. This switches whether a signal corresponding to the residual vibration generated in the ejection section D[m] is acquired and output as a detection potential signal VX to the detection circuit 23. At this time, the detection circuit 23 amplifies and shapes the signal waveform of the input detection potential signal VX according to the conduction states of the switches W1 and W2, and outputs it as a detection signal SK.

[0098] That is, the detection circuit 23 obtains the electromotive force generated in the piezoelectric element PZ as the detection potential signal VX by displacing the piezoelectric element PZ according to the residual vibration generated in the ejection part D, and outputs the signal corresponding to the obtained detection potential signal VX, that is, the signal waveform of the obtained detection potential signal VX after amplification and shaping, as the detection signal SK.

[0099] Furthermore, the detection signal SK output by the detection circuit 23 is input to the determination circuit 60. The determination circuit 60 determines the state of the ejection section D[m] that is the object of inspection based on the input detection signal SK. That is, the liquid ejection device 1 of this embodiment includes a determination circuit 60 for determining the state of the ejection section D of the object of inspection corresponding to the detection signal SK.

[0100] Here, the supply switching circuit 21 of the printhead 25 is composed of one or more semiconductor devices. Furthermore, at this time, a portion or all of the detection circuit 23 may also be installed in this semiconductor device along with the supply switching circuit 21.

[0101] As described above, the liquid ejection device 1 of this embodiment includes: a plurality of ejection sections D, each including a piezoelectric element PZ supplied with a supply drive signal Vin corresponding to a drive signal Com, ejecting ink according to the drive of the piezoelectric element PZ, and outputting a signal corresponding to the residual vibration generated after the piezoelectric element PZ is driven; a detection circuit 23, acquiring any one of the signals output by each of the plurality of ejection sections D corresponding to the residual vibration generated after the piezoelectric element PZ is driven, and outputting a detection signal SK corresponding to the acquired signal; switches Ws[1] to Ws[M], switching whether to supply the signal corresponding to the residual vibration generated after the piezoelectric element PZ is driven to the detection circuit 23; and a determination circuit 60, determining the state of the ejection section D[m] after correcting the detection signal SK.

[0102] 2.2 Printhead Movements During Ejection Processing

[0103] Next, the operation of the printhead 25 during the ejection process of the liquid ejection device 1 to form an image corresponding to the image information signal IP on the medium will be explained. Figure 8 This is a diagram illustrating an example of the various signals output by the control circuit 30 during the execution of the ejection process.

[0104] Control circuit 30 generates a drive waveform specification signal dCom and outputs it to drive circuit 40. This drive waveform specification signal dCom defines the signal waveform of the drive signal Com output by drive circuit 40 during the ejection process. Drive circuit 40 then executes the ejection process according to the input drive waveform specification signal dCom. Figure 8 The drive signal Com of the continuous signal waveforms of the drive waveforms PP1 configured in control period TQ1 and PP2 configured in control period TQ2, shown in each unit period TP, is supplied to the print head 25.

[0105] The driving waveform PP1 is a signal waveform as follows: the voltage value starts at a reference potential V0, changes to a potential VL1 that is lower than the reference potential V0, then becomes a potential VH1 that is higher than the reference potential V0, and finally ends at the reference potential V0. When this driving waveform PP1 is supplied to the piezoelectric element PZ[m], the piezoelectric element PZ[m] is driven to cause ink amount ξ1 to be ejected from the nozzle N[m]. That is, the driving waveform PP1 is a signal waveform for ejecting ink amount ξ1 from the nozzle N[m].

[0106] The driving waveform PP2 is a signal waveform as follows: the voltage value starts at a reference potential V0, changes to a potential VL2 which is lower than the reference potential V0, then becomes a potential VH2 which is higher than the reference potential V0, and finally ends at the reference potential V0. When this driving waveform PP2 is supplied to the piezoelectric element PZ[m], the piezoelectric element PZ[m] is driven to cause ink amount ξ2 less than ink amount ξ1 to be ejected from the nozzle N[m]. That is, the driving waveform PP2 is a signal waveform for ejecting ink amount ξ2 from the nozzle N[m].

[0107] Here, in this embodiment, the liquid ejection device 1 selects to form any one of the following on the medium P: a large dot, a midpoint smaller than a large dot, or a small dot smaller than a midpoint, or not to form a dot at all, during each unit period TP of the ejection process, thereby forming multi-grayscale dots on the medium P. That is, in this embodiment, the liquid ejection device 1 selects any one of the following amounts of ink from the ejection section D[m]: an amount of ink equivalent to a large dot, an amount of ink equivalent to a midpoint, or an amount of ink equivalent to a small dot, or not to eject ink at all, during each unit period TP of the ejection process. In this case, in this embodiment, the liquid ejection device 1 is described as follows: when the drive waveform PP1 is supplied to the piezoelectric element PZ[m], the amount of ink ejected from the ejection section D[m] is the amount of ink equivalent to a midpoint; when the drive waveform PP2 is supplied to the piezoelectric element PZ[m], the amount of ink ejected from the ejection section D[m] is the amount of ink equivalent to a small dot; and the sum of the ink amounts ξ1 and ξ2 is the amount of ink equivalent to a large dot.

[0108] Furthermore, during the liquid ejection device 1 of this embodiment performs ejection processing, the individual designated signal Sd[m] input to the connection state designation circuit 210 determines the on / off state of the switch Wc[m] in each of the control periods TQ1 and TQ2, and controls each unit period TP to supply the ejection section D[m] with either a supply drive signal Vin[m] containing the drive waveform PP1 configured in control period TQ1 and the drive waveform PP2 configured in control period TQ2, or a supply drive signal Vin[m] containing the drive waveform PP1 configured in control period TQ1, or a supply drive signal Vin[m] containing the drive waveform PP2 configured in control period TQ2, or a supply drive signal Vin[m] that does not contain either the drive waveform PP1 configured in control period TQ1 or the drive waveform PP2 configured in control period TQ2. Therefore, during a unit period TP during the liquid ejection device 1 performing the ejection process, it is controlled whether ink equivalent to a large dot, an amount equivalent to a medium dot, an amount equivalent to a small dot, or no ink is ejected from the ejection section D[m]. As a result, the dot size formed on the medium P is controlled.

[0109] Here, we will explain the relationship between the individual designation signals Sd[1] to Sd[M] contained in the printing data signal SI input to the connection state designation circuit 210 and the connection state designation signals Qc[1] to Qc[M] and Qs[1] to Qs[M] output by the connection state designation circuit 210 during the liquid ejection device 1 performing the ejection process, that is, an example of the decoding content of the individual designation signals Sd[1] to Sd[M] executed by the connection state designation circuit 210.

[0110] Figure 9 This is a diagram illustrating an example of the relationship between the individual specified signal Sd[m] and the connection status specified signals Qc[m] and Qs[m] during the execution of the ejection process.

[0111] like Figure 9As shown, when a separate designation signal Sd[m]=[0, 1, 1] is input to the connection state designation circuit 210, the connection state designation circuit 210 generates a connection state designation signal Qc[m] that is at level H during control period TQ1 and level H during control period TQ2, and outputs it to the control terminal of switch Wc[m]. Therefore, switch Wc[m] is controlled to be on during control period TQ1 and on during control period TQ2. Consequently, a supply drive signal Vin[m] containing the drive waveform PP1 is supplied to the piezoelectric element PZ[m] during control period TQ1, and a supply drive signal Vin[m] containing the drive waveform PP2 is supplied during control period TQ2. As a result, ink amount ξ1 is ejected from nozzle N[m] during control period TQ1, and ink amount ξ2 is ejected during control period TQ2. Furthermore, the ink amount ξ1 ejected during control period TQ1 and the ink amount ξ2 ejected during control period TQ2 land on medium P and combine, thereby forming a large dot on medium P in unit period TP.

[0112] Furthermore, when a separate designation signal Sd[m]=[0, 1, 0] is input to the connection state designation circuit 210, the connection state designation circuit 210 generates a connection state designation signal Qc[m] that is at level H during control period TQ1 and level L during control period TQ2, and outputs it to the control terminal of switch Wc[m]. Thus, switch Wc[m] is controlled to be on during control period TQ1 and to be off during control period TQ2. Therefore, a supply drive signal Vin[m] containing the drive waveform PP1 is supplied to the piezoelectric element PZ[m] during control period TQ1, but no supply drive signal Vin[m] containing the drive waveform PP2 is supplied during control period TQ2. Here, during the control period TQ2 when the piezoelectric element PZ[m] is not supplied with the supply drive signal Vin[m] containing the drive waveform PP2, the voltage value of the signal supplied to the upper electrode Zu[m], i.e., the reference potential V0, is maintained by the capacitive component of the piezoelectric element PZ[m]. That is, during the control period TQ2 when the piezoelectric element PZ[m] is not supplied with the supply drive signal Vin[m] containing the drive waveform PP2, a constant signal is supplied to the upper electrode Zu[m] at the reference potential V0. As a result, ink amount ξ1 is ejected from the nozzle N[m] during the control period TQ1, but no ink is ejected during the control period TQ2. Moreover, the ink amount ξ1 ejected during the control period TQ1 falls onto the medium P, thereby forming a midpoint on the medium P in a unit period TP.

[0113] Furthermore, when a separate designation signal Sd[m]=[0, 0, 1] is input to the connection state designation circuit 210, a connection state designation signal Qc[m] is generated, which is at level L during control period TQ1 and level H during control period TQ2, and is output to the control terminal of switch Wc[m]. Thus, switch Wc[m] is controlled to be non-conductive during control period TQ1 and to be conductive during control period TQ2. Therefore, the piezoelectric element PZ[m] is not supplied with a supply drive signal Vin[m] containing the drive waveform PP1 during control period TQ1, but is supplied with a supply drive signal Vin[m] containing the drive waveform PP2 during control period TQ2. Here, during the control period TQ1 when the piezoelectric element PZ[m] is not supplied with a supply drive signal Vin[m] containing the drive waveform PP1, the voltage value of the signal supplied to the upper electrode Zu[m], i.e., the reference potential V0, is maintained by the capacitive component of the piezoelectric element PZ[m]. That is, during the control period TQ1 when the piezoelectric element PZ[m] is not supplied with a supply drive signal Vin[m] containing the drive waveform PP1, a constant signal is supplied to the upper electrode Zu[m] at the reference potential V0. As a result, no ink is ejected from the nozzle N[m] during the control period TQ1, but an ink amount ξ2 is ejected during the control period TQ2. Moreover, the ink amount ξ2 ejected during the control period TQ2 falls onto the medium P, thereby forming a small dot on the medium P in a unit period TP.

[0114] Furthermore, when a separate designation signal Sd[m]=[0, 0, 0] is input to the connection state designation circuit 210, a connection state designation signal Qc[m] is generated, which is at level L during control period TQ1 and level L during control period TQ2, and is output to the control terminal of switch Wc[m]. Thus, switch Wc[m] is controlled to be non-conductive during control period TQ1 and non-conductive during control period TQ2. Therefore, the piezoelectric element PZ[m] is not supplied with a supply drive signal Vin[m] containing the drive waveform PP1 during control period TQ1, and is not supplied with a supply drive signal Vin[m] containing the drive waveform PP2 during control period TQ2. Here, during control periods TQ1 and TQ2 when the supply drive signal Vin[m] containing the drive waveform PP1 is not supplied to the piezoelectric element PZ[m], the voltage value of the signal supplied to the upper electrode Zu[m], i.e., the reference potential V0, is maintained in the upper electrode Zu[m] by the capacitive component of the piezoelectric element PZ[m]. That is, during control periods TQ1 and TQ2 when the supply drive signal Vin[m] containing the drive waveform PP1 is not supplied to the piezoelectric element PZ[m], a constant signal is supplied to the upper electrode Zu[m] at the reference potential V0. As a result, no ink is ejected from the nozzle N[m] during control period TQ1 and no ink is ejected during control period TQ2. Therefore, no dot is formed on the medium P in unit period TP.

[0115] As described above, when the liquid ejection device 1 performs ejection processing, during each of the control periods TQ1 and TQ2 in the unit period TP, the connection state specifying circuit 210 outputs connection state specifying signals Qs[1] to Qs[M] based on the logic levels of the individual specifying signals Sd[1] to Sd[M]. This controls the conduction state of the switches Wc[1] to Wc[m] in the control periods TQ1 and TQ2 in the unit period TP, and controls the amount of ink ejected from each of the ejection sections D[1] to D[M] during the control periods TQ1 and TQ2 in the unit period TP. That is, it controls the dot size formed on the medium P in the unit period TP. Therefore, during the period when the liquid ejection device 1 performs ejection processing, it is able to form an image corresponding to the image information signal IP on the medium P.

[0116] Here, as Figure 9As shown, during the liquid ejection device 1's ejection process, the connection state specifying circuit 210 continues to output the L-level connection state specifying signal Qs[m] regardless of the input individual specifying signal Sd[m]. Therefore, during the ejection process, the switch Ws[m] is controlled to be non-conductive. As a result, during the liquid ejection device 1's ejection process, the upper electrode Zu[m] and the wiring Ls are not electrically connected, and therefore, the signal corresponding to the residual vibration generated in the ejection section D[m] is not supplied to the detection circuit 23. Therefore, the detection circuit 23 does not acquire the detection potential signal VX during the liquid ejection device 1's ejection process. Therefore, although the illustration is omitted, during the liquid ejection device 1's ejection process, the connection state specifying circuit 210 continues to output the L-level connection state specifying signals Qf, Q1, and Q2.

[0117] 2.3 Determine the actions of the print head during processing.

[0118] Next, the determination process for the state of the ejection section D, which ejects ink to the medium P, will be explained. It is known that in an ejection section that ejects liquids such as ink by being driven by a piezoelectric element, residual vibrations are generated after the driving element has been activated. These residual vibrations in the ejection section are so-called damped vibrations, whose amplitude decreases over time. The waveform information of these damped vibrations, such as their amplitude, attenuation rate, period, and frequency, varies depending on the state of the ejection section. For example, when the viscosity of the liquid stored in the ejection section changes, the amplitude and attenuation rate of the residual vibrations generated in the ejection section change. Furthermore, for example, when air bubbles are mixed into the ejection section, the frequency of the residual vibrations generated in the ejection section increases.

[0119] In the liquid ejection device 1 of this embodiment, during the determination process for determining the state of the ejection section D that ejects ink to the medium, the supply switching circuit 21 of the printhead 25 acquires a signal corresponding to the residual vibration generated in the ejection section D[m] of the object under inspection, and outputs it as a detection potential signal VX to the detection circuit 23. The detection circuit 23 generates a detection signal SK by shaping the waveform of the input detection potential signal VX. Then, the determination circuit 60 calculates the waveform information such as the amplitude, period, and frequency of the detection potential signal VX based on the input detection signal SK, that is, the waveform information such as the amplitude, period, and frequency of the residual vibration generated in the ejection section D[m] of the object under inspection, and determines the state of the ejection section D[m] of the object under inspection based on the calculated waveform information. After that, the determination circuit 60 generates a state determination signal JH indicating the determination result and outputs it to the control circuit 30. Therefore, the control circuit 30 can acquire the state of the ejection section D[m] of the object under inspection, and correct various output signals based on the acquired state of the ejection section D[m] of the object under inspection, or notify the user of the state of the ejection section D[m] of the object under inspection.

[0120] Figure 10 This is a diagram illustrating an example of the various signals input to the supply switching circuit 21 of the print head 25 during the execution of the decision processing.

[0121] Control circuit 30 generates a drive waveform specification signal dCom and outputs it to drive circuit 40. This drive waveform specification signal dCom defines the signal waveform of the drive signal Com output by drive circuit 40 during the decision processing period. Drive circuit 40 then, based on the input drive waveform specification signal dCom, performs... Figure 10 During each unit period, TP generates a drive signal Com containing the drive waveform PS and supplies it to the print head 25.

[0122] The driving waveform PS is as follows: During control period TT1, the voltage value starts at the reference potential V0, changes to a potential VS1 that is lower than the reference potential V0, and then becomes a potential VS2 that is higher than the reference potential V0. During control periods TT2, TT3, and TT4, the potential VS2 is maintained, and during control period TT5, it becomes the reference potential V0 and ends. When this driving waveform PS is supplied to the piezoelectric element PZ[m], the piezoelectric element PZ[m] is driven so that ink is not ejected from the nozzle N[m]. After the piezoelectric element PZ[m] is driven, at the timing of the voltage value of the driving signal Com at potential VS2, residual vibration is generated in the ejection section D[m]. That is, the driving waveform PS is a signal waveform used to drive the piezoelectric element PZ[m] so that ink is not ejected from the nozzle N[m], so that the ejection section D[m] generates a predetermined residual vibration. If the piezoelectric element PZ[m] is supplied with the driving waveform PS, it is driven in a way that residual vibration is generated without ejecting ink from the ejection section D[m].

[0123] Furthermore, during the determination process performed by the liquid ejection device 1, the connection state designation circuit 210, in each of the control periods TT1 to TT5, controls the conduction states of switches Wc[1] to Wc[M], Ws[1] to Ws[M], Wf, W1, and W2 based on the individual designation signals Sd[1] to Sd[M] contained in the printing data signal SI. This supplies a supply drive signal Vin[m] containing the drive waveform PS to the ejection section D[m] of the object under inspection, and acquires a signal corresponding to the residual vibration generated in the ejection section D[m] of the object under inspection by the supply drive signal Vin[m] containing the drive waveform PS. This signal is then output to the detection circuit 23 as a detection potential signal VX. The detection circuit 23 generates a detection signal SK by shaping the waveform of the input detection potential signal VX, and the determination circuit 60 determines the state of the ejection section D[m] of the object under inspection based on the detection signal SK.

[0124] Here, we will explain the relationship between the individual designation signals Sd[1] to Sd[M] contained in the printing data signal SI input to the connection state designation circuit 210 and the connection state designation signals Qc[1] to Qc[M], Qs[1] to Qs[M], Qf, Q1, and Q2 output by the connection state designation circuit 210 during the determination process performed by the liquid ejection device 1. That is, an example of the decoding content of the individual designation signals Sd[1] to Sd[M] executed by the connection state designation circuit 210 during the determination process.

[0125] Figure 11This diagram illustrates an example of the relationship between the individual designation signal Sd[m] and the connection state designation signals Qc[m] and Qs[m] during the execution of the determination process. Here, we will explain the following: In the liquid ejection device 1 of this embodiment, during the execution of the determination process, if the ejection part D[m] is not the object of inspection, the control circuit 30 outputs the individual designation signal Sd[m]=[1, 0, 0] to the connection state designation circuit 210, and if the ejection part D[m] is the object of inspection, it outputs the individual designation signal Sd[m]=[1, 0, 1].

[0126] like Figure 11 As shown, when a single specified signal Sd[m]=[1, 0, 0] is input to the connection state specifying circuit 210, the connection state specifying circuit 210 generates a connection state specifying signal Qc[m] at level L during control periods TT1 to TT5 and outputs it to the control terminal of switch Wc[m]. It also generates a connection state specifying signal Qs[m] at level L during control periods TT1 to TT5 and outputs it to the control terminal of switch Ws[m]. Therefore, during control periods TT1 to TT5, switch Wc[m] is controlled to be non-conductive, and switch Ws[m] is controlled to be non-conductive. At this time, the piezoelectric element PZ[m] corresponding to the drive signal Com is not supplied to the ejector part D[m] which is not under inspection. Therefore, no residual vibration occurs in the ejector section D[m] which is not the object of inspection. At this time, even if the potential of the upper electrode Zu[m] of the piezoelectric element PZ[m] contained in the ejector section D[m] which is not the object of inspection changes, the signal accompanying the potential change is not supplied to the wiring Ls. Therefore, the determination of the state of the ejector section D[m] which is not the object of inspection is not performed.

[0127] Furthermore, when a separate designation signal Sd[m]=[1, 0, 1] is input to the connection state designation circuit 210, the connection state designation circuit 210 generates a connection state designation signal Qc[m] that is at high level during control periods TT1, TT2, and TT5, and at low level during control periods TT3 and TT4, and outputs it to the control terminal of switch Wc[m]. It also generates a connection state designation signal Qs[m] that is at high level during control periods TT2 to TT4, and at low level during control periods TT1 and TT5, and outputs it to the control terminal of switch Ws[m]. Thus, switch Wc[m] is controlled to be on during control periods TT1, TT2, and TT5, and controlled to be off during control periods TT3 and TT4; switch Ws[m] is controlled to be on during control periods TT2 to TT4, and controlled to be off during control periods TT1 and TT5.

[0128] Figure 12This diagram illustrates an example of the relationship between the individual specified signal Sd[m] and the connection state specified signals Qf, Q1, and Q2 during the execution of the decision process. Here, during the execution of the decision process, the connection state specified circuit 210 outputs the same logic level connection state specified signals Qf, Q1, and Q2 in each of the control periods TT1 to TT5, whether the individual specified signal Sd[m] = [1, 0, 0] or the individual specified signal Sd[m] = [1, 0, 1]. Therefore, in Figure 12 In the diagram, the individually specified signals Sd[m]=[1, 0, 0] and Sd[m]=[1, 0, 1] are illustrated together as the individually specified signal Sd[m]=[1, 0, 1]. ].

[0129] like Figure 12 As shown, a separate specified signal Sd[m]=[1, 0, ...] is input to the connection state specifying circuit 210. In the case of [condition], the connection status specifying circuit 210 generates a connection status specifying signal Qf that is at level H during control periods TT2 to TT4 and at level L during control periods TT1 and TT5, and outputs it to the control terminal of switch Wf; generates a connection status specifying signal Q1 that is at level H during control periods TT1, TT2, TT4, and TT5 and at level L during control period TT3, and outputs it to the control terminal of switch W1; and generates a connection status specifying signal Q2 that is at level H during control period TT3 and at level L during control periods TT1, TT2, TT4, and TT5, and outputs it to the control terminal of switch W2. Therefore, switch Wf is controlled to be on during control periods TT2 to TT4, and to be off during control periods TT1 and TT5; switch W1 is controlled to be on during control periods TT1, TT2, TT4, and TT5, and to be off during control period TT3; switch W2 is controlled to be on during control period TT3, and to be off during control periods TT1, TT2, TT4, and TT5.

[0130] Here, we will describe an example of the operation of the liquid ejection device 1 when a single specified signal Sd[m]=[1, 0, 1] is input to the connection state specifying circuit 210, namely, the operation of the detection circuit 23 to acquire the detection potential signal VX based on the signal corresponding to the residual vibration generated in the ejection part D[m] of the object under inspection.

[0131] Figure 13 This is a diagram illustrating an example of the acquisition operation of a detection potential signal VX based on a signal corresponding to the residual vibration generated in the ejection section D[m] of the inspected object. (See diagram for example.) Figure 13As shown, during each unit period TP of the execution determination process, a drive signal Com containing a drive waveform PS is supplied to the connection state designation circuit 210. The voltage value of the drive waveform PS starts at a reference potential V0 during the control period TT1, changes to a potential VS1 that is lower than the reference potential V0, becomes a potential VS2 that is higher than the reference potential V0, is maintained at potential VS2 during the control periods TT2 to TT4, becomes the reference potential V0 during the control period TT5 and ends.

[0132] Furthermore, during the judgment process, the control circuit 30 outputs a separate designation signal Sd[m]=[1, 0, 1] corresponding to the ejection portion D[m] of the inspection target to the connection state designation circuit 210. At this time, the ejection portions D[1]~D[m-1] and D[m+1]~D[M] are not the inspection targets. That is, the control circuit 30 outputs a separate designation signal Sd[1]~Sd[m-1] and Sd[m+1]~Sd[M]=[1, 0, 0] to the connection state designation circuit 210.

[0133] If a printed data signal SI containing individually specified signals Sd[m]=[1, 0, 1] and individually specified signals Sd[1]~Sd[m-1], Sd[m+1]~Sd[M]=[1, 0, 0] is input to the connection state designation circuit 210, then during control periods TT1 and TT2, switch Wc[m] is controlled to be on, and switches Wc[1]~Wc[m-1], Wc[m+1]~Wc[M] are controlled to be off. Therefore, the voltage value supplied to the upper electrode Zu[m] during control periods TT1 and TT2 starts at the reference potential V0, changes to a potential VS1 that is lower than the reference potential V0, and then becomes a potential VS2 that is higher than the reference potential V0, and the supply drive signal Vin[m] is maintained at potential VS2. Thereafter, the reference potential V0 is maintained in the upper electrodes Zu[1]~Zu[m-1], Zu[m+1]~Zu[M]. At this time, in the ejection section D[m] of the object under inspection, the voltage value of the supplied drive signal Vin[m] generates residual vibration at a constant timing with potential VS2. Then, the piezoelectric element Zm[m] deforms according to the residual vibration generated in the ejection section D[m] of the object under inspection, and an electromotive force corresponding to the deformation of the piezoelectric element Zm[m] is generated in the upper electrode Zu[m]. That is, in the upper electrode Zu[m] of the piezoelectric element PZ[m] included in the ejection section D[m] of the object under inspection, a signal corresponding to the residual vibration generated in the ejection section D[m] of the object under inspection is generated. In other words, the ejection section D[m] includes a piezoelectric element PZ[m] that outputs a signal corresponding to the electromotive force corresponding to the residual vibration.

[0134] Then, during control period TT2, switch Ws[m] is controlled to be on, switches Ws[1]~Ws[m-1] and Ws[m+1]~Ws[M] are controlled to be off, and switch Wf is controlled to be on. Thus, the signal corresponding to the residual vibration generated in the ejection portion D[m] of the inspected object is transmitted in wiring Ls as a detection potential signal VX. At this time, switch W1 is controlled to be on, and switch W2 is controlled to be off. Therefore, during control period TT2, the waveform shaping circuit 230 of the detection circuit 23 does not acquire the detection potential signal VX transmitted in wiring Ls, and therefore, does not output the detection signal aSK corresponding to the detection potential signal VX.

[0135] Then, during the control period TT3, switch W1 is controlled to be non-conducting and switch W2 is controlled to be conducting. The waveform shaping circuit 230 of the detection circuit 23 acquires the signal corresponding to the residual vibration generated in the ejection portion D[m] of the inspected object, i.e., the detection potential signal VX transmitted in the wiring Ls, and shapes the waveform of the acquired detection potential signal VX, outputting it as the detection signal aSK. The detection signal aSK output by the waveform shaping circuit 230 is converted into a digital signal in the AD conversion circuit 231 and then input as the detection signal SK to the judgment circuit 60.

[0136] The determination circuit 60 calculates the waveform information of the detection potential signal VX, such as amplitude, period, and frequency, based on the input detection signal SK; that is, the waveform information of the residual vibration generated in the ejection section D[m] of the object under inspection, such as amplitude, period, and frequency. Then, the determination circuit 60 determines the state of the ejection section D[m] of the object under inspection based on the calculated waveform information and outputs the state determination signal JH, which indicates the determination result, to the control circuit 30.

[0137] During the subsequent control period TT4, switch W1 is controlled to be on and switch W2 is controlled to be off, thereby stopping the acquisition of the detection potential signal VX transmitted in the wiring Ls and the output of the detection signal aSK by the waveform shaping circuit 230. Then, during the control period TT5, switch Wc[m] is controlled to be on and switch Ws[m] is controlled to be off, thereby stopping the supply of the signal generated in the upper electrode Zu[m] to the wiring Ls, and supplying the reference potential V0 driving signal Vin[m] to the upper electrode Zu[m] of the piezoelectric element PZ[m] of the ejection part D[m] of the object under inspection. As a result, the potential of the upper electrode Zu[m] of the piezoelectric element PZ[m] of the ejection part D[m] of the object under inspection is controlled to the reference potential V0.

[0138] 3. Structure and operation of the power supply circuit

[0139] Next, the functional structure of the power supply circuit 50 will be explained. Figure 14 This diagram illustrates an example of the functional configuration of the power supply circuit 50. (For example...) Figure 14 As shown, the power supply circuit 50 includes a control circuit 51, a conversion circuit 52, a smoothing circuit 53, and a feedback circuit 54. The conversion circuit 52 includes transistors 521 and 522, the smoothing circuit 53 includes an inductor 531 and a capacitor 532, and the feedback circuit 54 includes resistors 541 and 542. Furthermore, the power supply circuit 50 receives a power supply voltage signal VDC as input and outputs a power supply voltage signal VHV.

[0140] The control circuit 51 inputs the feedback signal FB1, which is described later, output by the feedback circuit 54. Based on the voltage value of the input feedback signal FB1, the control circuit 51 outputs signals indicating the conduction states of the transistors 521 and 522 contained in the control conversion circuit 52.

[0141] Transistors 521 and 522 are, for example, n-channel MOS-FETs (Metal-Oxide-Semiconductor Field-Effect Transistors). A power supply voltage signal VDC is input to the drain terminal of transistor 521. The source terminal of transistor 521 is electrically connected to the drain terminal of transistor 522. A ground potential is supplied to the source terminal of transistor 522. Furthermore, signals controlling the respective conduction states of transistors 521 and 522 are output from each of the input control circuits 51 that control the conduction state between the drain and source terminals of transistor 521 and transistor 522. That is, the conversion circuit 52, under the control of the control circuit 51, controls the conduction states of transistors 521 and 522 respectively, and outputs a pulse signal from the connection point where the source terminal of transistor 521 and the drain terminal of transistor 522 are electrically connected, switching the voltage value between the power supply voltage signal VDC and the ground potential. In other words, the conversion circuit 52 outputs a pulse signal corresponding to the power supply voltage signal VDC.

[0142] One end of inductor 531 is electrically connected to the source terminal of transistor 521 and the drain terminal of transistor 522. The other end of inductor 531 is electrically connected to one end of capacitor 532. Ground potential is supplied to the other end of capacitor 532. That is, smoothing circuit 53 constitutes a low-pass filter including inductor 531 and capacitor 532. Moreover, smoothing circuit 53 smooths the signal generated at the connection point where the source terminal of transistor 521 and the drain terminal of transistor 522 are electrically connected, i.e., the aforementioned pulse signal. That is, smoothing circuit 53 includes capacitor 532 and outputs a power supply voltage signal VHV after smoothing the pulse signal. The signal smoothed by smoothing circuit 53 is output from power supply circuit 50 as power supply voltage signal VHV.

[0143] One end of resistor 541 is electrically connected to the other end of inductor 531 and one end of capacitor 532. The other end of resistor 541 is electrically connected to one end of resistor 542. A ground potential is supplied to the other end of resistor 542. Furthermore, the potential at the connection point where the other end of resistor 541 and one end of resistor 542 are electrically connected is input to control circuit 51 as a feedback signal FB1. That is, feedback circuit 54 divides the voltage value at the connection point where the other end of inductor 531 and one end of capacitor 532 are electrically connected, i.e., the voltage value of the power supply voltage signal VHV output by power supply circuit 50, through resistors 541 and 542, and feeds it back to control circuit 51.

[0144] The operation of the power supply circuit 50 configured as described above will be explained. When the voltage value of the feedback signal FB1 input from the feedback circuit 54 is higher than a predetermined voltage value, the control circuit 51 outputs a signal that controls the connection between the drain and source terminals of transistor 521 to be non-conductive and a signal that controls the connection between the drain and source terminals of transistor 522 to be conductive. At this time, the voltage value at the connection point where the source terminals of transistor 521 and the drain terminals of transistor 522 are electrically connected becomes ground potential. Therefore, the voltage value of the power supply voltage signal VHV output from the smoothing circuit 53 decreases. On the other hand, when the voltage value of the feedback signal FB1 input from the feedback circuit 54 is lower than a predetermined voltage value, the control circuit 51 outputs a signal that controls the connection between the drain and source terminals of transistor 521 to be conductive and a signal that controls the connection between the drain and source terminals of transistor 522 to be non-conductive. At this time, the voltage value at the connection point where the source terminals of transistor 521 and the drain terminals of transistor 522 are electrically connected becomes the voltage value of the power supply voltage signal VDC. Therefore, the voltage value of the power supply voltage signal VHV output from the smoothing circuit 53 increases.

[0145] That is, the power supply circuit 50 controls the conduction state of transistors 521 and 522 to make the voltage value of the feedback signal FB1 input from the feedback circuit 54, i.e., the voltage value of the power supply voltage signal VHV, a constant value, thereby generating and outputting a power supply voltage signal VHV with a predetermined constant voltage value. In other words, the power supply circuit 50 is configured to include a DC / DC converter, which includes a switching power supply circuit. Furthermore, the structure of the power supply circuit 50 is not limited to... Figure 14 The structure shown could also be a structure that uses a diode instead of a transistor 522.

[0146] As described above, in the liquid ejection device 1 of this embodiment, the power supply circuit 50 includes a switching power supply circuit, which generates and outputs a power supply voltage signal VHV based on the power supply voltage signal VDC. Compared to a structure including a linear power supply circuit, the power consumption can be reduced in the power supply circuit 50 including such a switching power supply circuit. On the other hand, in the power supply circuit 50 including the switching power supply circuit, the conversion circuit 52 generates a pulse signal that switches between the voltage value of the power supply voltage signal VDC and the ground potential, and the smoothing circuit 53 generates the power supply voltage signal VHV by smoothing the pulse signal, thus superimposing a ripple voltage onto the output power supply voltage signal VHV.

[0147] Here, as Figure 2 As shown, the power supply voltage signal VHV output by the power supply circuit 50 is supplied to various parts of the ejection unit 5. Therefore, the ripple voltage superimposed on the power supply voltage signal VHV output by the power supply circuit 50 may affect the stability of the operation of the liquid ejection device 1.

[0148] Specifically, the power supply voltage signal VHV is input to the drive circuit 40. The drive circuit 40 amplifies the signal waveform specified by the drive waveform designation signal dCom based on the input power supply voltage signal VHV, thereby generating and outputting the drive signal Com. Therefore, when a ripple voltage is superimposed on the power supply voltage signal VHV, this ripple voltage is superimposed on the signal waveform of the drive signal Com output by the drive circuit 40 and the signal waveform of the supply drive signal Vin[m] corresponding to the drive signal Com. As a result, the driving accuracy of the piezoelectric element PZ[m] driven by the supply drive signal Vin[m] may be reduced, and the ejection accuracy of the ink ejected from the ejection section D[m] by the drive of the piezoelectric element PZ[m] may also be reduced.

[0149] Furthermore, the power supply voltage signal VHV, as connection status designation signals Qc[m] and Qs[m], is also supplied to the gate terminals of transistors Wnm and Wpm included in switches Wc[m] and Ws[m] respectively, and is also supplied to the back gate terminal of transistor Wpm included in switches Wc[m] and Ws[m]. At this time, the ripple voltage superimposed on the power supply voltage signal VHV may be superimposed on the drive signal Com transmitted in wiring Lc and the detection potential signal VX transmitted in wiring Ls corresponding to the residual vibration generated in the ejection part D[m] of the inspected object. As a result, the waveform accuracy of the drive signal Com and the corresponding supply drive signal Vin[m] decreases, the ejection accuracy of the ink ejected from the ejection section D[m] may be reduced due to the drive of the piezoelectric element PZ[m], and the determination accuracy of the state of the ejection section D[m] of the inspection object in the determination circuit 60 may also be reduced.

[0150] As described above, the stability of the operation of the liquid ejection device 1 may be reduced due to the influence of the ripple voltage superimposed on the power supply voltage signal VHV.

[0151] In particular, the voltage amplitude of the signal corresponding to the residual vibration generated in the ejection section D[m] of the object under inspection, i.e., the voltage amplitude of the detection potential signal VX, is about 10mV to 100mV. In contrast, the voltage amplitude of the ripple voltage superimposed on the power supply voltage signal VHV output by the power supply circuit 50 sometimes reaches 10mV to 100mV. Assuming that the ripple voltage superimposed on the power supply voltage signal VHV is superimposed on the signal corresponding to the residual vibration generated in the ejection section D[m] of the object under inspection, i.e., the detection potential signal VX, the waveform information such as the amplitude, amplitude attenuation rate, period, and frequency of the detection potential signal VX changes significantly. As a result, the accuracy of determining the state of the ejection section D[m] of the object under inspection in the determination circuit 60 may be significantly reduced.

[0152] In contrast, in the liquid ejection device of this embodiment, the capacitor 532 of the power supply circuit 50 has a characteristic structure that reduces the voltage amplitude of the ripple voltage superimposed on the power supply voltage signal VHV output by the power supply circuit 50. This reduces the possibility of decreased stability in the operation of the liquid ejection device 1 due to the influence of the ripple voltage superimposed on the power supply voltage signal VHV. The characteristic structure of the capacitor 532 in the power supply circuit 50 will be explained below.

[0153] Figure 15 , Figure 16 as well as Figure 17 This is a diagram illustrating an example of the structure of the capacitor 532 in the power supply circuit 50. Figure 15 This is a cross-sectional view of capacitor 532. Figure 16 This is a partial anatomical view of the capacitor element 550 of capacitor 532. Figure 17 This is a cross-sectional view used to illustrate the main parts of capacitor 532.

[0154] like Figure 15 As shown, capacitor 532 has capacitor element 550, outer packaging housing 560, sealing component 570, and lead terminals 580 and 590.

[0155] The outer packaging shell 560 is a bottomed cylindrical shape with one open side, made of metal or the like, and houses a capacitor element 550 inside. The bottom portion of the outer packaging shell 560 is approximately circular, and a valve (not shown) is formed near its center. This valve opens when the internal pressure of the outer packaging shell 560 increases, thereby reducing the internal pressure. The side portions of the outer packaging shell 560 are erected vertically from the outer edge of the bottom portion. The opening of the outer packaging shell 560 is sealed by a sealing member 570. The capacitor element 550 is housed within the space formed by the outer packaging shell 560 and the sealing member 570. Two through holes are formed in the sealing member 570. A lead terminal 580 is inserted through one of the two through holes in the sealing member 570, and a lead terminal 590 is inserted through the other through hole. Furthermore, the capacitor element 550 is connected to one end of each lead terminal 580 or 590. That is, with one end of the lead terminals 580 and 590 connected to the capacitor element 550, the other end is led out to the outside of the outer packaging housing 560.

[0156] like Figure 16 As shown, the capacitor element 550 includes an anode foil 552, a cathode foil 553, and a separator 551. The separator 551 is disposed between the anode foil 552 and the cathode foil 553. Furthermore, the anode foil 552 and the cathode foil 553 are overlapped and wound around the separator 551, thereby forming the capacitor element 550.

[0157] The anode foil 552 is formed from valve metals such as aluminum, tantalum, and niobium. The surface of the anode foil 552 is roughened by etching and then formed by a chemical conversion process. Figure 17 The oxide film 554 is shown. The cathode foil 553, like the anode foil 552, is formed of a valve metal such as aluminum, tantalum, or niobium. After the surface of the cathode foil 553 is roughened by etching, similar to the anode foil 552, it is then subjected to natural oxidation or formation treatment to form... Figure 17The oxide film 555 is shown. Such an anode foil 552 and cathode foil 553 are electrically connected to the corresponding lead terminals 580 and 590, respectively.

[0158] The width of the diaphragm 551 is greater than the winding width of the anode foil 552 and the cathode foil 553, and they are overlapped in a manner that clamps the anode foil 552 and the cathode foil 553. As the diaphragm 551, for example, a diaphragm formed of cellulose fibers that are chemically compatible with liquid substances such as conductive polymer particles and hydrophilic polymer compounds is preferably used.

[0159] In detail, the diaphragm 551 is made of a porous or pore-filled sheet-like electrically insulating material and is disposed between the anode foil 552 and the cathode foil 553. Thus, the diaphragm 551 prevents short circuits between the anode foil 552 and the cathode foil 553. Furthermore, the diaphragm 551 retains a solid electrolyte 557 and a liquid substance 558 within its porous or pore-filled structure as the electrolyte 556, which will be described later. Such a diaphragm 551 is a sheet-like structure with internal pores; for example, paper, nonwoven fabric, foam, etc., can be used.

[0160] Here, the substrate of the diaphragm 551 can be any electrically insulating material, but it is preferable to include a substrate mainly composed of polymers having hydroxyl groups. Thus, the diaphragm 551 is a liquid substance such as conductive polymer particles or hydrophilic polymer compounds, which is chemically compatible with the electrolyte 556 described later. As the substrate mainly composed of polymers having such hydroxyl groups, for example, natural fibers, regenerated fibers such as rayon, synthetic fibers, or mixtures thereof can be used. Furthermore, the polymer having hydroxyl groups can be any of natural, semi-synthetic, or synthetic materials, or mixtures thereof; cellulose or hemicellulose is preferred.

[0161] Return to Figure 15 The sealing component 570 prevents liquid substances from escaping from the inside of the outer packaging shell 560 to the outside, and also prevents foreign objects from entering from the outside of the outer packaging shell 560 to the inside. Therefore, the sealing component 570 is selected from materials that possess high airtightness, moderate elasticity to ensure a tight seal with the lead terminals 580 and 590, and maintain properties related to airtightness and elasticity even at high or low temperatures. For example, rubber materials such as ethylene-propylene-terpolymer (EPT), isobutylene-isoprene rubber (IIR), EPT-IIR blended rubber, and silicone rubber, as well as rubber composite materials formed by bonding resins such as phenolic resin, epoxy resin, and fluororesin to rubber, can be used for the sealing component 570. IIR, being a material with excellent airtightness, is preferred.

[0162] In addition, such as Figure 17As shown, in capacitor element 550, the gap between anode foil 552 and cathode foil 553, excluding the separator 551, is filled with electrolyte 556. Electrolyte 556 includes solid electrolyte 557 and liquid substance 558. Figure 17 This is an enlarged view of the main part of the capacitor element 550 of the capacitor 532, showing a schematic cross-sectional view between the anode foil 552 and the cathode foil 553 of the capacitor element 550, including the portion containing the electrolyte 556 held in the separator 551. Additionally, Figure 17 The schematic cross-sectional view shown is merely an example and is not limited to... Figure 17 As shown in the diagram.

[0163] like Figure 17 As shown, the surfaces of the anode foil 552 and the cathode foil 553 are roughened to increase the specific surface area, thus forming pits. Additionally, in Figure 17 In one example shown, wavy pits are formed on the surfaces of the anode foil 552 and the cathode foil 553, but the formation of pits is not limited to this. Furthermore, an oxide film 554 is formed on the surface of the anode foil 552 with pits through a chemical forming process, and an oxide film 555 is formed on the surface of the cathode foil 553 with pits through natural oxidation or a chemical forming process. Here, in Figure 17 In the image, a cross-section of the fibers constituting the diaphragm 551 is shown.

[0164] The voids between the anode foil 552 and the cathode foil 553, excluding the separator 551, are filled with a solid electrolyte 557 composed of a particulate conductive polymer compound. Furthermore, the conductive polymer compound serving as the solid electrolyte 557 forms a solid electrolyte phase by the aggregation of the particles. Here, the solid electrolyte phase comprising the conductive polymer compound serving as the solid electrolyte 557 may contain additives (not shown) in addition to the conductive polymer compound. Furthermore, in the following description, the voids between the anode foil 552 and the cathode foil 553, excluding the separator 551, are sometimes referred to as the first void.

[0165] A liquid substance 558 is introduced into the remaining void occupied by the solid electrolyte 557 in the first void. Here, in Figure 17In the illustration, liquid substance 558 is shown as a shaded area. Liquid substance 558 exists in a manner that surrounds solid electrolyte 557, thereby constituting a liquid substance phase. In electrolyte 556, the solid electrolyte phase containing solid electrolyte 557 and the liquid substance phase containing liquid substance 558 exist as different phases. Here, "existing as different phases" is not limited to the case of complete separation; they may also interpenetrate or mix in the boundary region between the solid electrolyte phase containing solid electrolyte 557 and the liquid substance phase containing liquid substance 558. Furthermore, in the following description, the remaining void occupied by solid electrolyte 557 in the first void is sometimes referred to as the second void. In addition, the liquid substance phase containing liquid substance 558 preferably wets the surfaces of the anode foil 552 and cathode foil 553 more by filling the second void, and is more located between solid electrolyte 557 and separator 551, but the liquid substance phase containing liquid substance 558 may not completely fill the second void.

[0166] Here, the solid electrolyte phase containing solid electrolyte 557 and the liquid phase containing liquid substance 558 contained in electrolyte 556 will be described.

[0167] The conductive polymer compound constituting the solid electrolyte phase 557 is, for example, a polymer compound with a π-electron conjugation system, preferably a polymer compound containing dopants and primarily exhibiting electronic and hole conductivity in order to express or improve conductivity.

[0168] As conductive polymers for such solid electrolytes 557, examples of usable compounds include polypyrrole, poly(N-methylpyrrole), polyaniline, polythiophene, poly(3-methylthiophene), poly(3,4-ethylenedioxythiophene), polyethylenedioxythiophene (PEDOT), poly(p-phenylene), polyfluorene, poly(p-styrene), and polythiophene ethylene. Furthermore, as dopants, anions such as toluenesulfonic acid, alkylbenzenesulfonic acid, naphthalenesulfonic acid, polyvinylsulfonic acid, polyallylsulfonic acid, polyacrylic acid sulfonic acid, polymethacrylic acid sulfonic acid, polyisoprene sulfonic acid, polystyrene sulfonic acid (PSS), and polyacrylic acid can be used.

[0169] Furthermore, the conductive polymer compound containing the solid electrolyte 557 can be introduced between the anode foil 552 and the cathode foil 553 through methods such as chemical polymerization, dispersion, and solution. The chemical polymerization method involves coating monomers and polymerization initiators (dopants, oxidants, catalysts, etc.) onto the electrode foil or impregnating them between the electrode foils and allowing them to polymerize, thereby forming a conductive polymer layer on the electrode foil. The dispersion method involves impregnating an aqueous dispersion of particulate conductive polymers into the element formed by winding the electrode foil and the separator, allowing the water to evaporate and filling the conductive polymers between the electrode foils. The solution method involves impregnating the element with a solution containing a self-doped conductive polymer compound and drying it to fill the element.

[0170] Furthermore, as described above, additives may also be included in the solid electrolyte phase along with the conductive polymer compound containing the solid electrolyte 557. The additives included in the solid electrolyte phase are components added during the synthesis of the conductive polymer compound or the formulation of the conductive polymer dispersion for purposes such as improving the conductivity and other properties of the conductive polymer compound that is the solid electrolyte 557, repairing defects in the oxide film, or other purposes. Examples of such additives include conductivity enhancers, ion-conducting compounds, alkaline compounds (pH adjusters), water-soluble compounds, and water-dispersible compounds.

[0171] The liquid phase containing liquid substance 558 is liquid at the operating temperature, or at least a portion of the operating temperature, and exists in the second void in a manner that surrounds the solid electrolyte phase. It is a functional liquid phase containing liquid substances that enhance or supplement the solid electrolyte 557. This liquid phase is liquid regardless of the type of substance, and thus, unlike additives contained in the solid electrolyte phase, it has the following characteristics: it can be introduced after the solid electrolyte phase formation process, and it can be introduced in large quantities into the fine spaces between the separator 551 and the solid electrolyte phase. Furthermore, since the liquid phase is at least liquid, it is preferable to exist between the separator 551 and the solid electrolyte phase, and it has the function of reducing the degradation reaction of the separator 551 caused by dopants released from the solid electrolyte phase. Such a liquid phase can possess various useful functions by including specific components in the liquid substance 558.

[0172] The liquid substance 558 constituting the liquid phase may be an organic solvent, particularly a high-molecular-weight organic solvent, as the liquid having the minimum functions described above. However, it is preferable that, in addition to the electrolyte, hydrophilic polymeric compounds, components with hydroxyl groups may also be used, such as polyoxyethylene and its derivatives (polyglycerol), water-soluble polyurethane, water-soluble polyester, water-soluble polyamide, water-soluble polyimide, water-soluble polyacrylic acid, water-soluble polyacrylamide, water-soluble organosilicon, polyvinyl alcohol, polyacrylic acid, etc., or mixtures thereof.

[0173] Furthermore, one of the representative functions of liquid phases is the repair function of oxide films. Besides electrolytes, oxide film repair can also be achieved through hydrophilic polymers, hydroxyl-containing components such as polyoxyethylene and its derivatives (polyglycerol), water-soluble polyurethane, water-soluble polyester, water-soluble polyamide, water-soluble polyimide, water-soluble polyacrylic acid, water-soluble polyacrylamide, polyvinyl alcohol, polyacrylic acid, and water-soluble organosilicon.

[0174] The ability of electrolytes to repair oxide film defects is known. For example, if the liquid phase contains a hydrophilic polymer, the hydrophilic polymer can retain moisture, and thus the retained moisture can be used to preferentially repair oxide film defects. Oxide film defects may occur during the fabrication of capacitor 532 or during long-term use of capacitor 532, but in either case, the oxide film can be repaired by the reaction of the moisture retained by the hydrophilic polymer with the electrode foil metal at the defective portion. Therefore, capacitor 532 with high voltage withstand capability, low leakage current, and long lifespan can be obtained.

[0175] In this embodiment, the liquid phase specifically refers to a phase that is liquid at atmospheric pressure and room temperature, for example, at one atmosphere and 25°C, but it is acceptable as long as it is liquid at the operating temperature or a portion thereof. Furthermore, "liquid" means having fluidity, and may also be a viscous substance. Because the liquid phase is liquid, it can impregnate and fill the remaining gaps, i.e., the details of the second pores, between the separator 551 and the solid electrolyte phase between the electrode foils. Moreover, since the liquid phase can be introduced into the details of the second pores, a larger quantity of liquid phase can be introduced, and the liquid phase can permeate the details of the second pores, allowing the active ingredients to reliably reach the sites requiring oxide film repair and other functions.

[0176] Furthermore, the hydrophilic polymers that can be included in the liquid phase are polymers with hydrophilic groups. Representative hydrophilic groups include hydroxyl, ether, amino, carbonyl, carboxyl, nitro, sulfonic acid, amide, and phosphate groups. However, even when hydrophilic polymers contain sulfonic acid groups, they are different from dopants incorporated into conductive polymers, and the distinction lies in whether or not they are doped. In this invention, the hydrophilic polymer does not contain dopants. The number of hydrophilic groups in such a hydrophilic polymer is only one or more, but can also be two or more. Furthermore, it can be three or more, four or more, five or more, six or more, or even more. The more hydrophilic groups, the higher the water retention capacity; therefore, from this viewpoint, a higher number of hydrophilic groups is preferred. However, from the viewpoint of operability and cost of oxide film repair agents, such as viscosity and hygroscopicity, an excessive number of hydrophilic groups may be undesirable.

[0177] Furthermore, the hydrophilic polymer compounds can be, for example, polyepoxides, polyolefins, polyphenylene ethers, water-soluble polyacrylic acid, water-soluble polyurethanes, water-soluble polyesters, water-soluble polyamides, water-soluble polyimides, water-soluble organosilicones, branched polyethers, polyglycerols, and their derivatives. Additionally, water-soluble polyacrylic acid, water-soluble polyurethanes, water-soluble polyesters, water-soluble polyamides, water-soluble polyimides, and water-soluble organosilicones can be, for example, polyurethanes, polyesters, polyamides, polyimides, and organosilicones with sulfonic acid groups introduced into them.

[0178] As described above, the capacitor element 550 of the capacitor 532 of this embodiment is configured such that: a separator 551 is located between the anode foil 552 and the cathode foil 553; a solid electrolyte phase containing a conductive polymer compound as a solid electrolyte 557 is located between the anode foil 552 and the cathode foil 553 and there is no first void in the separator 551; and a liquid phase containing a liquid substance 558 is located in the first void and there is no second void in the first void where there is no conductive polymer compound as a solid electrolyte 557. That is, the capacitor 532 has: an anode foil 552 and a cathode foil 553, on which an oxide film 554 is formed; a separator 551 between the anode foil 552 and the cathode foil 553; and an electrolyte 556, in which a first void exists between the anode foil 552 and the cathode foil 553 other than the separator 551. The electrolyte 556 includes: a solid electrolyte phase containing solid electrolyte 557; and a liquid phase, which exists in a manner surrounding the solid electrolyte 557 and includes liquid substance 558.

[0179] Therefore, in the capacitor 532 of this embodiment, by using a solid electrolyte phase containing a solid electrolyte 557 and a liquid phase containing a liquid substance 558 as the electrolyte 556, and utilizing the repair function of the oxide film generated by the liquid phase containing the liquid substance 558, the reliability of the capacitor 532 can be improved. Furthermore, by utilizing the conductive polymer as the solid electrolyte 557, the low ESR characteristic of the capacitor 532 can be achieved. Moreover, by achieving the low ESR characteristic of the capacitor 532, the voltage amplitude of the ripple voltage superimposed on the power supply voltage signal VHV output by the smoothing circuit 53 including the capacitor 532 can be reduced. That is, by using the capacitor 532 with the above-described structure, the reliability of the power supply circuit 50 can be improved, and the ripple voltage superimposed on the power supply voltage signal VHV output by the power supply circuit 50 can be reduced. As a result, the stability of the operation of each part of the power supply voltage signal VHV supplied is improved, and the stability of the operation of the liquid ejection device 1 is improved.

[0180] Furthermore, by including a solid electrolyte phase containing a solid electrolyte 557 as the electrolyte 556, the ESR variation associated with temperature changes in capacitor 532 can be reduced, ensuring that the difference between the DC resistance component (ESR) of capacitor 532 at 100 kHz and 0°C and the DC resistance component (ESR) of capacitor 532 at 100 kHz and 80°C is less than 100 mΩ. In the power supply circuit 50 with such a capacitor 532 and the liquid ejection device 1 including the power supply circuit 50, the possibility of ripple voltage variation superimposed on the output power supply voltage signal VHV can be reduced even under varying ambient temperatures. That is, in the power supply circuit 50 and the liquid ejection device 1 including the power supply circuit 50, the possibility of increased ripple voltage superimposed on the power supply voltage signal VHV can be reduced even under varying ambient temperatures. As a result, the stability of the operation of each part of the supplied power supply voltage signal VHV is further improved, and the stability of the operation of the liquid ejection device 1 is improved.

[0181] Here, the ejection unit 5 is equivalent to a liquid ejection unit. Furthermore, the power supply circuit 50 is an example of a power supply circuit, the capacitor 532 included in the smoothing circuit 53 is an example of a capacitor, the oxide film 554 formed on the surface of the anode foil 552 is an example of an oxide film, and the gap between the anode foil 552 and the cathode foil 553, excluding the diaphragm 551 (i.e., the first gap), is an example of a gap portion. Additionally, the detection circuit 23 is an example of a residual vibration detection circuit, the AD conversion circuit 231 is an example of an AD conversion circuit, the switch Wc[m] is an example of a first switching circuit, the switch Ws[m] is an example of a second switching circuit, and the connecting component 17 is an example of a BtoB connector. Furthermore, the power supply voltage signal VDC is an example of a first power supply voltage signal, the power supply voltage signal VHV is an example of a second power supply voltage signal, the detection potential signal VX is an example of a residual vibration signal, and the detection signal SK is an example of a residual vibration detection signal.

[0182] 4. Effects

[0183] As described above, in the liquid ejection device 1 and ejection unit 5 of this embodiment, the power supply circuit 50 that receives the input power supply voltage signal VDC and outputs the power supply voltage signal VHV to the switches Wc[1]~Wc[M] and Ws[1]~Ws[M] is configured as a switching power supply circuit. The switching power supply circuit has: a conversion circuit 52 that outputs a pulse signal corresponding to the power supply voltage signal VDC; and a smoothing circuit 53 that includes a capacitor 532 that outputs the power supply voltage signal VHV after smoothing the pulse signal. Furthermore, in the liquid ejection device 1 and ejection unit 5 of this embodiment, the capacitor 532 of the smoothing circuit 53 of the power supply circuit 50, which is configured as a switching power supply circuit, includes: an anode foil 552 and a cathode foil 553, on which an oxide film 554 is formed; a separator 551 between the anode foil 552 and the cathode foil 553; and an electrolyte 556, in which a first gap exists between the anode foil 552 and the cathode foil 553 other than the separator 551. The electrolyte 556 is composed of a solid electrolyte phase and a liquid phase. The solid electrolyte phase includes a solid electrolyte 557, and the liquid phase exists in a manner that surrounds the solid electrolyte 557 and includes a liquid phase 558.

[0184] In this capacitor 532, the reliability of the capacitor 532 can be improved by utilizing the repair function of the oxide film generated by the liquid phase containing the liquid substance 558, and the low ESR characteristic of the capacitor 532 can be achieved by utilizing the conductive polymer as the solid electrolyte 557. Moreover, by achieving the low ESR characteristic of the capacitor 532, the voltage amplitude of the ripple voltage superimposed on the power supply voltage signal VHV output by the smoothing circuit 53 including the capacitor 532 can be reduced. That is, by using the capacitor 532 with the above-described structure, the reliability of the power supply circuit 50 can be improved, and the ripple voltage superimposed on the power supply voltage signal VHV output by the power supply circuit 50 can be reduced. As a result, the stability of the operation of each part of the power supply voltage signal VHV supplied is improved, and the stability of the operation of the liquid ejection device 1 is improved.

[0185] Furthermore, in the liquid ejection device 1 and ejection unit 5 of this embodiment, the capacitor 532 of the smoothing circuit 53 of the power supply circuit 50, which is configured as a switching power supply circuit, includes: an anode foil 552 and a cathode foil 553, on which an oxide film 554 is formed; a separator 551 between the anode foil 552 and the cathode foil 553; and an electrolyte 556, in which a first gap exists between the anode foil 552 and the cathode foil 553 other than the separator 551. The electrolyte 556 is composed of a solid electrolyte phase and a liquid phase. The solid electrolyte phase includes a solid electrolyte 557, and the liquid phase exists in a manner that surrounds the solid electrolyte 557 and includes a liquid phase 558. This reduces the variation of ESR with temperature changes, and makes the difference between the DC resistance component (ESR) of the capacitor 532 at a frequency of 100 kHz and a temperature of 0 °C and the DC resistance component (ESR) of the capacitor 532 at a frequency of 100 kHz and a temperature of 80 °C less than 100 m ohms.

[0186] In the power supply circuit 50 with such a capacitor 532 and the liquid ejection device 1 including the power supply circuit 50, even in the event of temperature changes in the various parts of the liquid ejection device 1 including the liquid ejection device 1, the ejection unit 5, and the power supply circuit 50, the possibility of ripple voltage fluctuations superimposed on the output power supply voltage signal VHV can be reduced. That is, in the power supply circuit 50 and the liquid ejection device 1 including the power supply circuit 50, even in the event of temperature changes, the possibility of an increase in ripple voltage superimposed on the power supply voltage signal VHV can be reduced. As a result, the stability of the operation of the various parts supplied with the power supply voltage signal VHV is further improved, and the stability of the operation of the liquid ejection device 1 is improved.

[0187] Furthermore, in the liquid ejection device 1 and ejection unit 5 of this embodiment, switches Ws[1] to Ws[M], which are supplied with power supply voltage signal VHV, switch whether to supply detection potential signal VX to detection circuit 23. That is, a signal corresponding to residual vibration with small voltage amplitude is transmitted to switches Ws[1] to Ws[M]. Even in this case, the ripple voltage superimposed on power supply voltage signal VHV is reduced in the liquid ejection device 1 and ejection unit 5 of this embodiment. Therefore, the possibility of ripple voltage superimposed on power supply voltage signal VHV affecting the signal corresponding to residual vibration transmitted in switches Ws[1] to Ws[M] is reduced by the parasitic capacitance contained in switches Ws[1] to Ws[M]. As a result, the waveform accuracy of detection potential signal VX acquired by detection circuit 23 is improved, and the accuracy of detection signal SK output by detection circuit 23 is improved. Therefore, the determination accuracy in determination circuit 60, which determines the state of ejection section D of the object under inspection based on detection signal SK, is improved, and the stability of operation of liquid ejection device 1 is further improved.

[0188] 5. Variations

[0189] In this embodiment, it is described that the piezoelectric element PZ ejects ink from the ejection section D by driving it and outputs a signal corresponding to the residual vibration generated in the ejection section D. However, the ejection section D may also have the following structure: it includes a piezoelectric element as a driving element for ejecting ink and a piezoelectric element as a detection element for detecting the residual vibration generated in the ejection section D. Furthermore, in this case, the driving element for ejecting ink in the ejection section D is not limited to a piezoelectric element as long as it is an element capable of converting an electrical signal into a mechanical vibration, and the detection element for detecting the residual vibration generated in the ejection section D is not limited to a piezoelectric element as long as it is an element capable of converting a mechanical vibration into an electrical signal.

[0190] Furthermore, in this embodiment, it is explained that the potential output generated in the upper electrode Zu of the piezoelectric element PZ is a signal corresponding to the residual vibration generated in the ejection section D. However, it is also possible to output the potential generated in the lower electrode Zd of the piezoelectric element PZ as a signal corresponding to the residual vibration generated in the ejection section D.

[0191] Furthermore, the signal corresponding to the residual vibration generated in the ejection section D can be a signal of current oscillating according to the residual vibration generated in the ejection section D, or it can be a signal of voltage oscillating according to the residual vibration generated in the ejection section D. Therefore, the detection circuit 23 can be a structure that detects the voltage value of the signal corresponding to the residual vibration generated in the ejection section D, or it can be a structure that detects the current value of the signal corresponding to the residual vibration generated in the ejection section D.

[0192] Furthermore, in this embodiment, it is described that the signal waveform of the drive signal Com output by the drive circuit 40 is switched with drive waveforms PP1, PP2, drive waveform PS and drive waveform PC. However, the drive circuit 40 may also include amplifier circuits for output drive waveforms PP1 and PP2, amplifier circuits for output drive waveform PS and amplifier circuits for output drive waveform PC, respectively.

[0193] The embodiments and variations have been described above, but the present invention is not limited to these embodiments and can be implemented in various ways without departing from its spirit. For example, the above embodiments can also be appropriately combined.

[0194] This invention includes structures that are substantially the same as those described in the embodiments (e.g., structures with the same function, method, and result, or structures with the same purpose and effect). Furthermore, this invention includes structures that replace non-essential parts of the structures described in the embodiments. Furthermore, this invention includes structures capable of achieving the same effect or purpose as the structures described in the embodiments. Furthermore, this invention includes structures incorporating known techniques into the structures described in the embodiments.

[0195] The following content is derived from the above implementation method.

[0196] One method of liquid ejection device includes: Conveying section, conveying medium; The ejector section ejects liquid into the medium by being supplied with a drive signal; A first switching circuit switches whether to supply the drive signal to the ejector section; and The power supply circuit receives a first power supply voltage signal and outputs a second power supply voltage signal to the first switching circuit. The power supply circuit has the following features: The conversion circuit outputs a pulse signal corresponding to the first power supply voltage signal; and The smoothing circuit, including a capacitor, outputs a second power supply voltage signal after smoothing the pulse signal. The capacitor comprises: an anode foil and a cathode foil, on the surface of which an oxide film is formed; a separator disposed between the anode foil and the cathode foil; and an electrolyte, wherein there are voids between the anode foil and the cathode foil, excluding the separator. The electrolyte comprises: a solid electrolyte phase containing a conductive polymeric compound; and a liquid phase existing in a manner surrounding the solid electrolyte phase and containing a liquid substance.

[0197] In this liquid ejection device, in the power supply circuit, a smoothing circuit smooths the pulse signal output by the conversion circuit corresponding to the first power supply voltage signal and outputs it as a second power supply voltage signal. The smoothing circuit includes a capacitor comprising: an anode foil and a cathode foil, on which an oxide film is formed; a diaphragm disposed between the anode foil and the cathode foil; and an electrolyte, with voids existing between the anode foil and the cathode foil except for the diaphragm. The electrolyte comprises: a solid electrolyte phase containing a conductive polymer compound; and a liquid phase surrounding the solid electrolyte phase and containing the liquid substance, thereby reducing the DC resistance component (ESR) generated in the capacitor. As a result, the power supply circuit can reduce the voltage amplitude of the ripple voltage superimposed on the second power supply voltage signal output by smoothing the pulse signal. Therefore, the stability of the operation of each part of the liquid ejection device, including the first switching circuit that operates with the supply of the second power supply voltage signal, is improved. That is, the stability of the operation of the liquid ejection device is improved.

[0198] In one embodiment of the liquid ejection device, Alternatively, the difference between the DC resistance component of the capacitor at a frequency of 100kHz and a temperature of 0℃ and the DC resistance component of the capacitor at a frequency of 100kHz and a temperature of 80℃ is less than 100m ohms.

[0199] In this liquid ejection device, the capacitor included in the smoothing circuit that outputs the second power supply voltage signal comprises: an anode foil and a cathode foil, on which an oxide film is formed; a diaphragm disposed between the anode foil and the cathode foil; and an electrolyte, in which there are gaps between the anode foil and the cathode foil except for the diaphragm. The electrolyte comprises: a solid electrolyte phase containing a conductive polymer compound; and a liquid phase surrounding the solid electrolyte phase and containing the liquid substance. This allows the difference between the DC resistance component of the capacitor at a frequency of 100 kHz and a temperature of 0°C and the DC resistance component of the capacitor at a frequency of 100 kHz and a temperature of 80°C to be less than 100 mΩ. Therefore, the power supply circuit can reduce the possibility that the voltage amplitude of the ripple voltage superimposed on the second power supply voltage signal output by smoothing the pulse signal will vary due to temperature. Thus, the stability of the operation of each part of the liquid ejection device, including the first switching circuit that operates with the supply of the second power supply voltage signal, is further improved, and the overall stability of the liquid ejection device is further enhanced.

[0200] In one embodiment of the liquid ejection device, it may include: The printhead includes the ejection section and the first switching circuit; and The circuit board is provided with the power supply circuit. The printhead and the circuit board are electrically connected via a BtoB connector.

[0201] In one embodiment of the liquid ejection device, it may include: The residual vibration detection circuit acquires a residual vibration signal corresponding to the residual vibration generated in the ejection section, and outputs a residual vibration detection signal corresponding to the residual vibration signal. The determination circuit determines the state of the ejection section based on the residual vibration detection signal; and The second switching circuit switches whether to supply the residual vibration signal to the residual vibration detection circuit. The second power supply voltage signal is supplied to the second switching circuit.

[0202] In this liquid ejection device, the power supply circuit reduces the voltage amplitude of the ripple voltage superimposed on the second power supply voltage signal, which is output by smoothing the pulse signal. This reduces the likelihood that the ripple voltage superimposed on the second power supply voltage signal will affect the residual vibration signal corresponding to the residual vibration with a small voltage value. As a result, the accuracy of the ejection section's state determination in the determination circuit is improved.

[0203] In one embodiment of the liquid ejection device, it may be: The residual vibration detection circuit includes an AD conversion circuit and outputs a digital signal as the residual vibration detection signal.

[0204] In one embodiment of the liquid ejection device, it may be: The residual vibration detection circuit acquires the electromotive force generated by the displacement of the piezoelectric element according to the residual vibration as the residual vibration signal.

[0205] In one embodiment of the liquid ejection device, it may be: The ejector section ejects liquid by being driven by the piezoelectric element.

[0206] One method of liquid ejection unit includes: The ejector section ejects liquid into the medium by being supplied with a drive signal; A first switching circuit switches whether to supply the drive signal to the ejector section; and The power supply circuit receives a first power supply voltage signal as input and outputs a second power supply voltage signal to the first switching circuit. The power supply circuit has the following features: The conversion circuit outputs a pulse signal corresponding to the first power supply voltage signal; and The smoothing circuit, including a capacitor, outputs a second power supply voltage signal after smoothing the pulse signal. The capacitor comprises: an anode foil and a cathode foil, on which an oxide film is formed; a separator disposed between the anode foil and the cathode foil; and an electrolyte present in the voids between the anode foil and the cathode foil, excluding the separator. The electrolyte comprises: a solid electrolyte phase containing a conductive polymeric compound; and a liquid phase existing in a manner surrounding the solid electrolyte phase and containing a liquid substance.

[0207] In this liquid ejection unit, within the power supply circuit, a smoothing circuit smooths the pulse signal output from the conversion circuit corresponding to the first power supply voltage signal and outputs it as a second power supply voltage signal. The smoothing circuit includes a capacitor comprising: an anode foil and a cathode foil, both with oxide films formed on their surfaces; a diaphragm disposed between the anode and cathode foils; and an electrolyte present in the voids between the anode and cathode foils, excluding the diaphragm. The electrolyte comprises: a solid electrolyte phase containing a conductive polymer compound; and a liquid phase surrounding the solid electrolyte phase and containing the liquid substance. This reduces the DC resistance component (ESR) generated in the capacitor. As a result, the power supply circuit can reduce the voltage amplitude of the ripple voltage superimposed on the second power supply voltage signal output by smoothing the pulse signal. Therefore, the stability of the operation of each part of the liquid ejection unit, including the first switching circuit that operates with the supply of the second power supply voltage signal, is improved.

[0208] In one embodiment of the liquid ejection unit, it may be: The difference between the DC resistance component of the capacitor at a frequency of 100kHz and a temperature of 0℃ and the DC resistance component of the capacitor at a frequency of 100kHz and a temperature of 80℃ is less than 100m ohms.

[0209] In this liquid ejection unit, the capacitor included in the smoothing circuit that outputs the second power supply voltage signal comprises: an anode foil and a cathode foil, on which an oxide film is formed; a diaphragm disposed between the anode foil and the cathode foil; and an electrolyte present in the voids between the anode foil and the cathode foil, excluding the diaphragm. The electrolyte comprises: a solid electrolyte phase containing a conductive polymer compound; and a liquid phase surrounding the solid electrolyte phase and containing the liquid substance. This allows the difference between the DC resistance component of the capacitor at a frequency of 100 kHz and a temperature of 0°C and the DC resistance component of the capacitor at a frequency of 100 kHz and a temperature of 80°C to be less than 100 mΩ. Therefore, the power supply circuit can reduce the possibility that the voltage amplitude of the ripple voltage superimposed on the second power supply voltage signal output by smoothing the pulse signal will vary due to temperature. Consequently, the stability of the operation of each part of the liquid ejection unit, including the first switching circuit that operates with the supply of the second power supply voltage signal, is further improved.

[0210] In one embodiment of the liquid ejection unit, it may include: The printhead includes the ejection section and the first switching circuit; and The circuit board is provided with the power supply circuit. The printhead and the circuit board are electrically connected via a BtoB connector.

[0211] In one embodiment of the liquid ejection unit, it may include: The residual vibration detection circuit acquires a residual vibration signal corresponding to the residual vibration generated in the ejection section, and outputs a residual vibration detection signal corresponding to the residual vibration signal. The determination circuit determines the state of the ejection section based on the residual vibration detection signal; and The second switching circuit switches whether to supply the residual vibration signal to the residual vibration detection circuit. The second power supply voltage signal is supplied to the second switching circuit.

[0212] In this liquid ejection unit, the power supply circuit reduces the voltage amplitude of the ripple voltage superimposed on the second power supply voltage signal, which is output by smoothing the pulse signal. This reduces the likelihood that the ripple voltage superimposed on the second power supply voltage signal will affect the residual vibration signal corresponding to the small residual vibration. As a result, the accuracy of the ejection section's state determination in the determination circuit is improved.

[0213] In one embodiment of the liquid ejection unit, it may be: The residual vibration detection circuit includes an AD conversion circuit and outputs a digital signal as the residual vibration detection signal.

[0214] In one embodiment of the liquid ejection unit, it may be: The residual vibration detection circuit acquires the electromotive force generated by the displacement of the piezoelectric element according to the residual vibration as the residual vibration signal.

[0215] In one embodiment of the liquid ejection unit, it may be: The ejector section ejects liquid by being driven by the piezoelectric element.

Claims

1. A liquid ejection device, characterized in that, The liquid ejection device includes: Conveying section, conveying medium; The ejector section ejects liquid into the medium by being supplied with a drive signal; The first switching circuit switches whether to supply the driving signal to the ejector section; as well as The power supply circuit receives a first power supply voltage signal as input and outputs a second power supply voltage signal to the first switching circuit. The power supply circuit has the following features: The conversion circuit outputs a pulse signal corresponding to the first power supply voltage signal; and The smoothing circuit includes a capacitor and outputs a second power supply voltage signal after smoothing the pulse signal. The capacitor has: The anode foil and cathode foil have an oxide film formed on their surfaces; A diaphragm is disposed between the anode foil and the cathode foil; and The electrolyte exists in the voids between the anode foil and the cathode foil, excluding the membrane. The electrolyte comprises: A solid electrolyte phase, comprising conductive polymeric compounds; and A liquid phase exists in a manner that surrounds the solid electrolyte phase and contains liquid matter.

2. The liquid ejection device according to claim 1, characterized in that, The difference between the DC resistance component of the capacitor at a frequency of 100kHz and a temperature of 0℃ and the DC resistance component of the capacitor at a frequency of 100kHz and a temperature of 80℃ is less than 100m ohms.

3. The liquid ejection device according to claim 1, characterized in that, The liquid ejection device includes: The printhead includes the ejection section and the first switching circuit; and The circuit board is provided with the power supply circuit. The printhead and the circuit board are electrically connected via a BtoB connector.

4. The liquid ejection device according to any one of claims 1 to 3, characterized in that, The liquid ejection device includes: The residual vibration detection circuit acquires a residual vibration signal corresponding to the residual vibration generated in the ejection section, and outputs a residual vibration detection signal corresponding to the residual vibration signal. The determination circuit determines the state of the ejection section based on the residual vibration detection signal; as well as The second switching circuit switches whether to supply the residual vibration signal to the residual vibration detection circuit. The second power supply voltage signal is supplied to the second switching circuit.

5. The liquid ejection device according to claim 4, characterized in that, The residual vibration detection circuit includes an AD conversion circuit and outputs a digital signal as the residual vibration detection signal.

6. The liquid ejection device according to claim 4, characterized in that, The residual vibration detection circuit acquires the electromotive force generated by the displacement of the piezoelectric element according to the residual vibration as the residual vibration signal.

7. The liquid ejection device according to claim 6, characterized in that, The ejector section ejects liquid by being driven by the piezoelectric element.

8. A liquid ejection unit, characterized in that, The liquid ejection unit includes: The ejector section ejects liquid into the medium by being supplied with a drive signal; A first switching circuit switches whether to supply the drive signal to the ejector section; and The power supply circuit receives a first power supply voltage signal as input and outputs a second power supply voltage signal to the first switching circuit. The power supply circuit has the following features: The conversion circuit outputs a pulse signal corresponding to the first power supply voltage signal; and The smoothing circuit includes a capacitor and outputs a second power supply voltage signal after smoothing the pulse signal. The capacitor has: The anode foil and cathode foil have an oxide film formed on their surfaces; A diaphragm is disposed between the anode foil and the cathode foil; and The electrolyte exists in the voids between the anode foil and the cathode foil, excluding the membrane. The electrolyte comprises: A solid electrolyte phase, comprising conductive polymeric compounds; and A liquid phase exists in a manner that surrounds the solid electrolyte phase and contains liquid matter.

9. The liquid ejection unit according to claim 8, characterized in that, The difference between the DC resistance component of the capacitor at a frequency of 100kHz and a temperature of 0℃ and the DC resistance component of the capacitor at a frequency of 100kHz and a temperature of 80℃ is less than 100m ohms.

10. The liquid ejection unit according to claim 8, characterized in that, The liquid ejection unit includes: The printhead includes the ejection section and the first switching circuit; and The circuit board is provided with the power supply circuit. The printhead and the circuit board are electrically connected via a BtoB connector.

11. The liquid ejection unit according to any one of claims 8 to 10, characterized in that, The liquid ejection unit includes: The residual vibration detection circuit acquires a residual vibration signal corresponding to the residual vibration generated in the ejection section, and outputs a residual vibration detection signal corresponding to the residual vibration signal. The determination circuit determines the state of the ejection section based on the residual vibration detection signal; as well as The second switching circuit switches whether to supply the residual vibration signal to the residual vibration detection circuit. The second power supply voltage signal is supplied to the second switching circuit.

12. The liquid ejection unit according to claim 11, characterized in that, The residual vibration detection circuit includes an AD conversion circuit and outputs a digital signal as the residual vibration detection signal.

13. The liquid ejection unit according to claim 11, characterized in that, The residual vibration detection circuit acquires the electromotive force generated by the displacement of the piezoelectric element according to the residual vibration as the residual vibration signal.

14. The liquid ejection unit according to claim 13, characterized in that, The ejector section ejects liquid by being driven by the piezoelectric element.

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