Liquid ejection device and printhead

Abstract

The present application provides a liquid ejection device and a print head that can solve problems caused by the temperature detection unit provided inside the print head. The liquid ejection device includes a drive signal output circuit that outputs a drive signal and a print head that receives the drive signal and ejects a liquid, the print head including a temperature detection unit that detects temperature information of a pressure chamber, the drive signal output circuit including a modulation circuit that outputs a modulation signal, an amplification circuit that outputs an amplified modulation signal, a smoothing circuit that outputs a drive signal after smoothing the amplified modulation signal, and a basic drive signal output circuit that outputs a basic drive signal after correction based on the temperature information, the frequency of the amplified modulation signal when the temperature information that the basic drive signal output circuit uses to correct the basic drive signal is detected by the temperature detection unit being higher than the frequency of the amplified modulation signal when the temperature information that the basic drive signal output circuit does not use to correct the basic drive signal is detected by the temperature detection unit.

Description

TECHNICAL FIELD

[0001] The present application relates to a liquid ejection device and a print head. BACKGROUND

[0002] In a liquid ejection device that ejects liquid, a configuration is known in which a print head having a piezoelectric element, a pressure chamber, and a nozzle that communicates with the pressure chamber is provided. Moreover, the print head changes the volume of the pressure chamber by driving the piezoelectric element, and thereby ejects liquid supplied to the pressure chamber from the nozzle. In such a liquid ejection device, a configuration is known in which driving control of the piezoelectric element is performed in accordance with the temperature of ink stored in the print head, and thereby ejection control that is appropriate for the temperature of the ink is realized. For example, Patent Document 1 discloses a liquid ejection device and a liquid ejection head (print head) that can reduce the temperature difference between the detected temperature and the temperature in the pressure chamber, and improve the detection accuracy of the temperature of the pressure chamber, by having a temperature detection portion that detects the temperature of the pressure chamber in which ink is stored, inside the print head having a piezoelectric element, a pressure chamber, and a nozzle.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2022-124599

[0004] However, in the liquid ejection device described in Patent Document 1, since the temperature detection portion is provided inside the print head, there is a possibility that the detection accuracy of the temperature of the pressure chamber will decrease, and there is room for further improvement. SUMMARY

[0005] One embodiment of a liquid ejecting apparatus according to the present application includes a drive signal output circuit that outputs a drive signal, and a print head that receives the drive signal and ejects a liquid. The print head includes a piezoelectric element that includes a first electrode, a second electrode, and a piezoelectric body, the piezoelectric body is positioned between the first electrode and the second electrode in a stacking direction in which the first electrode, the second electrode, and the piezoelectric body are stacked, the piezoelectric element receives the drive signal and is driven, a vibration plate that is positioned on one side in the stacking direction with respect to the piezoelectric element and is deformed by driving of the piezoelectric element, a pressure chamber substrate that is positioned on the one side in the stacking direction with respect to the vibration plate and is provided with a plurality of pressure chambers whose volumes change in accordance with the deformation of the vibration plate, a switching circuit that switches whether or not the drive signal is supplied to the piezoelectric element, a wiring substrate that is provided with the switching circuit, and a temperature detection portion that is positioned on the other side in the stacking direction with respect to the vibration plate, is electrically connected to the wiring substrate, and detects temperature information of the pressure chambers. The drive signal output circuit includes a modulation circuit that outputs a modulation signal obtained by modulating a base drive signal that is a basis of the drive signal, an amplification circuit that outputs an amplified modulation signal obtained by amplifying the modulation signal, a smoothing circuit that outputs the drive signal obtained by smoothing the amplified modulation signal, a feedback circuit that feeds back the drive signal to the modulation circuit, and a base drive signal output circuit that outputs the base drive signal that is corrected in accordance with the temperature information. The frequency of the amplified modulation signal when the temperature detection portion detects the temperature information used by the base drive signal output circuit to correct the base drive signal is higher than the frequency of the amplified modulation signal when the temperature detection portion detects the temperature information not used by the base drive signal output circuit to correct the base drive signal.

[0006] A print head according to an embodiment of the present application is a print head that receives a drive signal output from a drive signal output circuit and ejects a liquid, wherein the drive signal output circuit includes a modulation circuit that outputs a modulation signal obtained by modulating a base drive signal, an amplification circuit that outputs an amplified modulation signal obtained by amplifying the modulation signal, a smoothing circuit that outputs the drive signal obtained by smoothing the amplified modulation signal, a feedback circuit that feeds back the drive signal to the modulation circuit, and a base drive signal output circuit that outputs a base drive signal that becomes a basis of the drive signal, which is corrected based on temperature information output from the print head, the print head including a piezoelectric element that includes a first electrode, a second electrode, and a piezoelectric body, the piezoelectric body being positioned between the first electrode and the second electrode in a stacking direction in which the first electrode, the second electrode, and the piezoelectric body are stacked, the piezoelectric element receiving the drive signal to be driven, a vibration plate that is positioned on one side in the stacking direction with respect to the piezoelectric element and deforms under the drive of the piezoelectric element, a pressure chamber substrate that is positioned on the one side in the stacking direction with respect to the vibration plate and is provided with a plurality of pressure chambers whose volumes change according to the deformation of the vibration plate, a switching circuit that switches whether or not to supply the drive signal to the piezoelectric element, a wiring substrate on which the switching circuit is provided, and a temperature detection portion that is positioned on the other side in the stacking direction with respect to the vibration plate, is electrically connected to the wiring substrate, and detects the temperature information of the pressure chambers, the frequency of the amplified modulation signal when the temperature information detected by the temperature detection portion is output to the base drive signal output circuit being higher than the frequency of the amplified modulation signal when the temperature information detected by the temperature detection portion is not output to the base drive signal output circuit. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 FIG. 1 is a diagram showing the schematic configuration of a liquid ejecting apparatus.

[0008] Figure 2 FIG. 2 is a diagram showing the functional configuration of the liquid ejecting apparatus.

[0009] Figure 3 FIG. 3 is a diagram showing the configuration of a drive circuit.

[0010] Figure 4 FIG. 4 is a diagram showing the configuration of a drive signal selection circuit.

[0011] Figure 5 FIG. 5 is a diagram for explaining the relationship between a latch signal LAT, a conversion signal CH, a clock signal SCK, a head control signal DI, and a selection signal S.

[0012] Figure 6 FIG. 6 is a diagram showing an example of the data configuration of the head control signal DI.

[0013] Figure 7 is a view showing a decoding content of the decoder.

[0014] Figure 8 is a view showing a configuration of a selection circuit corresponding to the piezoelectric element.

[0015] Figure 9 is a view showing an example of a signal waveform of the drive signal COM.

[0016] Figure 10 is a view showing an example of the head control signal DI.

[0017] Figure 11 is a view showing a specific example of a decoding content of the decoder.

[0018] Figure 12 is a view showing an example of the drive signal VOUT output from the selection circuit when the selection signal S shown in Figure 11 is supplied.

[0019] Figure 13 is an exploded perspective view showing a structure of the ejection module.

[0020] Figure 14 is a plan view of the ejection module.

[0021] Figure 15 is a view showing a cross section of the IV-IV section shown in Figure 14 .

[0022] Figure 16 is a detail view of a main part of Figure 15 .

[0023] Figure 17 is a view showing a cross section of the VI-VI section shown in Figure 14 .

[0024] Figure 18 is a view showing an example of the acquisition timing of the ejection module to acquire the temperature by the print head.

[0025] BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 1 liquid ejection device, 2 ink container, 10 control mechanism, 20 print head, 21 carriage, 22 ejection module, 24 temperature detection circuit, 26 temperature information output circuit, 30 movement mechanism, 31 carriage motor, 32 endless belt, 40 conveyance mechanism, 41 conveyance motor, 42 conveyance roller, 50 drive circuit, 52 reference voltage signal output circuit, 54 frequency measurement circuit, 60 piezoelectric element, 90 linear encoder, 100 control circuit, 200 drive signal selection circuit, 210 selection control circuit, 222a first register, 222b second register, 224a first latch circuit, 224b second latch circuit, 226 decoder, 230 selection circuit, 232 inverter, 234 transmission gate, 260 control logic circuit, 261 register group for SP, 262 selection control signal generation section, 270 selection signal output section, 310 pressure chamber substrate, 311 partition wall, 312 pressure chamber, 312a, 312b end portion, 315 communication plate, 316 nozzle communication passage, 317 first manifold portion, 318 second manifold portion, 319 supply communication passage, 320 nozzle plate, 321 nozzle, 330 protection substrate, 331 holding portion, 332 through-hole, 340 housing member, 341 accommodation portion, 342 third manifold portion, 343 connection port, 344 supply port, 345 plastic substrate, 346 sealing film, 347 fixed substrate, 348 opening portion, 349 plastic portion, 350 vibration plate, 351 elastic film, 352 insulator film, 360 first electrode, 360a, 360b end portion, 370 piezoelectric body, 370a, 370b end portion, 371 groove portion, 380 second electrode, 380a, 380b end portion, 385 wiring portion, 391 independent lead electrode, 392 common lead electrode, 392a, 392b extension portion, 393, 393a, 393b measurement lead electrode, 400 manifold, 401 resistance wiring, 410 active portion, 415 inactive portion, 420 wiring substrate, 421, 500 integrated circuit, 510 modulation circuit, 512, 513 adder, 514 comparator, 515 inverter, 516 integral attenuator, 517 attenuator, 520 gate drive circuit, 521, 522 gate driver, 550 amplification circuit, 560 smoothing circuit, 570, 572 feedback circuit, C1-C5, C7 capacitor, D1 diode, L1 inductor, M1, M2 transistor, P medium, R1-R6 resistor. DETAILED DESCRIPTION

[0027] The following describes preferred embodiments of the present application using the accompanying drawings. The drawings used are schematic drawings for ease of explanation. Furthermore, the embodiments described below do not unduly limit the content of the present application described in the claims. In addition, not all of the components described below are essential components of the present application.

[0028] 1. Structure of liquid discharge apparatus

[0029] Figure 1 is a diagram showing the schematic configuration of a liquid discharge apparatus 1. The liquid discharge apparatus 1 in the present embodiment is described taking as an example an inkjet printer of a serial printing type that forms an image on a medium P by moving a carriage 21 on which a print head 20 that discharges ink as an example of a liquid is mounted, back and forth along a scanning axis, and discharging ink toward the medium P that is transported in a transport direction. As the medium P used in such a liquid discharge apparatus 1, any printing object such as a printing sheet, a resin film, cloth, or the like can be used.

[0030] As shown in Figure 1 , the liquid discharge apparatus 1 is provided with an ink container 2, a control mechanism 10, the carriage 21, a moving mechanism 30, and a transport mechanism 40.

[0031] The ink container 2 stores therein a plurality of inks to be discharged toward the medium P. As the colors of the inks stored in the ink container 2, black, cyan, magenta, yellow, red, gray, and the like can be given. As the ink container 2 that stores inks, an ink cartridge, a bag-shaped ink bag formed of a flexible film, an ink tank that can be replenished with ink, and the like can be used.

[0032] The control mechanism 10 includes a processing circuit such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array) and a storage circuit such as a semiconductor memory, and controls each element of the liquid discharge apparatus 1 including the print head 20.

[0033] The carriage 21 mounts the print head 20, and is fixed to a loop-shaped belt 32 included in the moving mechanism 30. In addition, the ink container 2 can also be mounted to the carriage 21.

[0034] The print head 20 mounted to the carriage 21 is inputted with a control signal Ctrl-H for controlling the print head 20 and a drive signal COM for driving the print head 20, which are outputted from the control mechanism 10. In addition, the ink stored in the ink container 2 is supplied to the print head 20 via a pipe not shown. Further, the print head 20 discharges the ink supplied from the ink container 2 in accordance with the inputted control signal Ctrl-H and drive signal COM.

[0035] The moving mechanism 30 includes a carriage motor 31 and a ring belt 32. The carriage motor 31 operates in accordance with a control signal Ctrl-C input from the control mechanism 10. The ring belt 32 rotates in conjunction with the operation of the carriage motor 31. Thus, the carriage 21 fixed to the ring belt 32 moves back and forth on the scan axis. That is, the carriage 21 moves back and forth along the scan axis intersecting the conveyance direction of the medium P.

[0036] The conveyance mechanism 40 includes a conveyance motor 41 and a conveyance roller 42. The conveyance motor 41 operates in accordance with a control signal Ctrl-T input from the control mechanism 10. The conveyance roller 42 rotates in conjunction with the operation of the conveyance motor 41. In conjunction with the rotation of the conveyance roller 42, the medium P is conveyed toward the conveyance direction.

[0037] As described above, the liquid discharge device 1 causes the print head 20 mounted on the carriage 21 to discharge ink toward the medium P in conjunction with the conveyance of the medium P by the conveyance mechanism 40 and the back-and-forth movement of the carriage 21 by the moving mechanism 30, thereby causing the ink to land on an arbitrary position on the surface of the medium P and forming a desired image on the medium P.

[0038] 2. Functional Configuration of Liquid Discharge Device

[0039] Next, the functional configuration of the liquid discharge device 1 will be described. Figure 2 is a view showing the functional configuration of the liquid discharge device 1. As shown in Figure 2 , the liquid discharge device 1 is provided with a control mechanism 10, a print head 20, a carriage motor 31, a conveyance motor 41, and a linear encoder 90.

[0040] The control mechanism 10 has a drive circuit 50, a reference voltage signal output circuit 52, a frequency measurement circuit 54, and a control circuit 100. The control circuit 100 includes, for example, a processing circuit such as a CPU or an FPGA and a storage circuit such as a semiconductor memory. An image information signal containing image data and the like is input to the control circuit 100 from an external device such as a host computer communicably connected to the liquid discharge device 1. The control circuit 100 generates various signals for controlling the liquid discharge device 1 in accordance with the input image information signal, and outputs them to the corresponding configurations.

[0041] In the specific example, in addition to the above-described image information signal, a detection signal based on the scan position of the carriage 21 is input to the control circuit 100 from the linear encoder 90. The control circuit 100 grasps the scan position of the print head 20 mounted on the carriage 21 in accordance with the input detection signal. Also, the control circuit 100 generates and outputs various signals corresponding to the scan position of the print head 20 and the image information signal.

[0042] In detail, the control circuit 100 generates a control signal Ctrl-C for controlling the movement of the print head 20 along the scanning axis in accordance with the scanning position of the print head 20, and outputs it to the carriage motor 31. As a result, the carriage motor 31 operates to control the movement of the print head 20 along the scanning axis and the scanning position mounted on the carriage 21. In addition, the control circuit 100 generates a control signal Ctrl-T for controlling the conveyance of the medium P, and outputs it to the conveyance motor 41. As a result, the conveyance motor 41 operates to control the movement of the medium P along the conveyance direction. Further, the control signal Ctrl-C can be input to the carriage motor 31 after being signal-converted via a drive circuit not shown, and the control signal Ctrl-T can be input to the conveyance motor 41 after being signal-converted via a drive circuit not shown.

[0043] In addition, the control circuit 100 generates a head control signal DI1 to DIn, a conversion signal CH, a latch signal LAT, and a clock signal SCK as a control signal Ctrl-H for controlling the print head 20 in accordance with an image information signal input from an external device and the scanning position of the print head 20 input from the linear encoder 90, and outputs them to the print head 20.

[0044] Further, the control circuit 100 outputs a basic drive signal dO as a digital signal to the drive circuit 50. The drive circuit 50 performs digital / analog signal conversion on the input basic drive signal dO, and then performs D-stage amplification on the converted analog signal to generate a drive signal COM, and outputs it to the print head 20. That is, the basic drive signal dO output from the control circuit 100 is a digital signal that specifies the waveform of the drive signal COM. Here, the basic drive signal dO can also be an analog signal as long as it specifies the waveform of the drive signal COM output from the drive circuit 50. Further, details of the drive circuit 50 will be described later.

[0045] The reference voltage signal output circuit 52 generates a reference voltage signal VBS, and outputs it to the print head 20. The reference voltage signal VBS output from the reference voltage signal output circuit 52 is a signal that becomes the potential of the drive reference of the piezoelectric element 60 described later, and for example, can be a signal that is constantly at a ground potential, or a direct current voltage signal that is constantly at a potential of 5.5 V or 6 V or the like. The reference voltage signal output circuit 52 can also be integrally formed with the drive circuit 50.

[0046] The frequency measurement circuit 54 detects the frequency of the amplified modulation signal AMs output from the drive circuit 50. Further, the frequency measurement circuit 54 generates a frequency determination signal Fm that becomes an H level for a certain period when the detected frequency of the amplified modulation signal AMs becomes a maximum value, and outputs it to the control circuit 100. The control circuit 100 calculates the voltage value of the drive signal COM at the instant when the input frequency determination signal Fm becomes an H level, based on the base drive signal dO output to the drive circuit 50, and stores the calculation result. Note that the frequency determination signal Fm output from the frequency measurement circuit 54 is not limited to a signal that becomes an H level when the measured frequency of the amplified modulation signal AMs is a maximum value, but can be a signal that becomes an H level when the measured frequency of the amplified modulation signal AMs is a prescribed threshold value or more.

[0047] In addition, the control circuit 100 generates a temperature acquisition request signal TD for acquiring the temperature of the print head 20 at a prescribed timing, and outputs it to the print head 20. In addition, the temperature information signal TI output from the print head 20 in accordance with the temperature acquisition request signal TD is input to the control circuit 100. That is, the temperature information signal TI containing the temperature information of the print head 20 is input to the control circuit 100. The control circuit 100 corrects the control signals Ctrl-H, Ctrl-C, Ctrl-T, and the base drive signal dO in accordance with the input temperature information signal TI. That is, the control circuit 100 outputs the base drive signal dO corrected in accordance with the temperature information signal TI.

[0048] The print head 20 has the ejection modules 22-1 to 22-n and the temperature information output circuit 26. In addition, the ejection modules 22-1 to 22-n each include the drive signal selection circuit 200, the temperature detection circuit 24, and the piezoelectric elements 60[1] to 60[m].

[0049] In the ejection module 22-1, the head control signal DI1, the conversion signal CH, the latch signal LAT, and the clock signal SCK output from the control circuit 100, the drive signal COM output from the drive circuit 50, and the reference voltage signal VBS output from the reference voltage signal output circuit 52 are input.

[0050] The clock signal SCK, the latch signal LAT, the shift signal CH, the head control signal DI1, and the drive signal COM input to the ejection module 22-1 are input to the drive signal selection circuit 200. The drive signal selection circuit 200 generates the drive signals VOUT[1] to VOUT[m] by selecting or deselecting the signal waveform of the drive signal COM in accordance with the input clock signal SCK, the latch signal LAT, the shift signal CH, and the head control signal DI1. Further, the drive signal selection circuit 200 outputs the generated drive signals VOUT[1] to VOUT[m] to one end of the corresponding piezoelectric elements 60[1] to 60[m] independently. In addition, the other end of the piezoelectric elements 60[1] to 60[m] is commonly input with the reference voltage signal VBS. Further, the piezoelectric elements 60[1] to 60[m] are driven by the potential difference between the drive signals VOUT[1] to VOUT[m] input to one end independently and the reference voltage signal VBS commonly input to the other end. The amount of ink corresponding to the drive of each of the piezoelectric elements 60[1] to 60[m] is ejected from the ejection module 22-1.

[0051] Here, in the print head 20 of the present embodiment, the description is made with the drive signal VOUT[1] corresponding to the piezoelectric element 60[1] and the drive signal VOUT[m] corresponding to the piezoelectric element 60[m]. That is, the description is made with the drive signal VOUT[1] generated by the drive signal selection circuit 200 being input to one end of the piezoelectric element 60[1] and the drive signal VOUT[m] generated by the drive signal selection circuit 200 being input to one end of the piezoelectric element 60[m].

[0052] Here, the piezoelectric elements 60[1] to 60[m] are all of the same constitution, and are sometimes referred to as the piezoelectric element 60 without distinction. At this time, the description is made with the drive signal VOUT being supplied to one end of the piezoelectric element 60 as the drive signals VOUT[1] to VOUT[m]. That is, the description is sometimes made with the piezoelectric element 60 being driven by the potential difference between the drive signal VOUT supplied to one end and the reference voltage signal VBS supplied to the other end.

[0053] In addition, the temperature detection circuit 24 provided to the ejection module 22-1 detects the temperature of the ejection module 22-1. Further, the temperature detection circuit 24 outputs the detected temperature of the ejection module 22-1 as the temperature detection information TH1 to the temperature information output circuit 26.

[0054] Here, the ejection modules 22-2 to 22-n differ only in the signals input and the signals output, have the same constitution as the ejection module 22-1, and perform the same operation.

[0055] That is, the ejection module 22-n is input with the clock signal SCK, the latch signal LAT, the conversion signal CH, the head control signal DIn, the drive signal COM, and the reference voltage signal VBS. Further, the drive signal selection circuit 200 included in the ejection module 22-n generates the drive signals VOUT[1] to VOUT[m] by selecting or deselecting the signal waveform of the drive signal COM in accordance with the input clock signal SCK, the latch signal LAT, the conversion signal CH, and the head control signal DIn. The drive signals VOUT[1] to VOUT[m] generated by the drive signal selection circuit 200 included in the ejection module 22-n are input to one end of the corresponding piezoelectric elements 60[1] to 60[m] included in the ejection module 22-n. The other ends of the piezoelectric elements 60[1] to 60[m] included in the ejection module 22-n are commonly input with the reference voltage signal VBS. Thus, the piezoelectric elements 60[1] to 60[m] included in the ejection module 22-n are driven, and ink is ejected from the ejection module 22-n in an amount corresponding to the driving of the piezoelectric elements 60[1] to 60[m]. Further, the temperature detection circuit 24 included in the ejection module 22-n detects the temperature of the ejection module 22-n and outputs the detected temperature as the temperature detection information THn.

[0056] Here, in the following description, the ejection module 22 is sometimes referred to without distinguishing the ejection module 22-1 from the ejection module 22-n. At this time, the description is made with the clock signal SCK, the latch signal LAT, the conversion signal CH, the head control signal DI, the drive signal COM, and the reference voltage signal VBS being input to the ejection module 22, and the temperature detection information TH indicating the temperature of the ejection module 22 being output.

[0057] The temperature detection information TH1 to THn output by the temperature detection circuit 24 included in each of the ejection modules 22-1 to 22-n and the temperature acquisition request signal TD output by the control circuit 100 are input to the temperature information output circuit 26. The temperature information output circuit 26 amplifies and holds the temperature detection information TH1 to THn, respectively. Further, the temperature information output circuit 26 outputs, as the temperature information signal TI, the corresponding one of the signals amplified with respect to the held temperature detection information TH1 to THn in accordance with the temperature acquisition request signal TD input from the control circuit 100. Such a temperature information output circuit 26 includes an amplification circuit that amplifies the temperature detection information TH1 to THn, a processor such as a microcomputer that receives the input temperature acquisition request signal TD and outputs the temperature information signal TI amplified with respect to the temperature detection information TH1 to THn, and a storage circuit that amplifies and holds the temperature detection information TH1 to THn, respectively.

[0058] Further, the temperature information output circuit 26 can also hold the temperature detection information TH1 to THn output from the temperature detection circuits 24 provided in the ejection modules 22-1 to 22-n, respectively, and amplify the held temperature detection information TH1 to THn, respectively, in accordance with a temperature acquisition request signal TD input from the control circuit 100, and output the amplified signals as temperature information signals TI.

[0059] As described above, the liquid ejection apparatus 1 of the present embodiment is provided with the drive circuit 50 that outputs the drive signal COM and the print head 20 that receives the drive signal COM and ejects ink. In other words, the print head 20 receives the drive signal COM output from the drive circuit 50 and ejects ink.

[0060] 3. Configuration of Drive Circuit

[0061] Next, the configuration and operation of the drive circuit 50 that outputs the drive signal COM will be described. Figure 3 is a diagram showing the configuration of the drive circuit 50. The drive circuit 50 has an integrated circuit 500, an amplification circuit 550, a smoothing circuit 560, feedback circuits 570, 572, and other electronic components. In addition, the drive circuit 50 outputs the drive signal COM to the print head 20. Figure 3 The frequency measurement circuit 54 that measures the frequency of the amplified modulation signal AMs output from the drive circuit 50 is described in conjunction with the drive circuit 50.

[0062] The integrated circuit 500 has a plurality of terminals including a terminal In, a terminal Bst, a terminal Hdr, a terminal Sw, a terminal Gvd, a terminal Ldr, a terminal Gnd, a terminal Vfb, and a terminal Ifb. The integrated circuit 500 is electrically connected to an unillustrated substrate provided externally via the plurality of terminals. In addition, the integrated circuit 500 includes a DAC (Digital to Analog Converter) 511, a modulation circuit 510, and a gate drive circuit 520.

[0063] The DAC 511 converts an input digital signal base drive signal dO to an analog signal base drive signal aO and outputs it to the modulation circuit 510. The base drive signal aO output from this DAC 511 is equivalent to the signal after amplification of the drive signal COM. That is, the base drive signal aO is equivalent to a signal that is a target before amplification to become the drive signal COM, and the base drive signals dO, aO are signals that define the signal waveform of the drive signal COM.

[0064] The modulation circuit 510 generates a modulation signal Ms that modulates the base drive signal aO and outputs it to the gate drive circuit 520. The modulation circuit 510 includes adders 512, 513, a comparator 514, an inverter 515, an integral attenuator 516, and an attenuator 517.

[0065] The integrator 516 integrates the drive signal COM input via the terminal Vfb and outputs to the input terminal on the - side of the adder 512. The input terminal on the + side of the adder 512 is input with the basic drive signal aO. Further, the adder 512 outputs to the input terminal on the + side of the adder 513 a voltage obtained by subtracting the voltage of the input terminal on the - side from the voltage of the input terminal on the + side.

[0066] The attenuator 517 outputs to the input terminal on the - side of the adder 513 a voltage obtained by attenuating the high frequency component of the drive signal COM input via the terminal Ifb. The voltage output from the adder 512 is input to the input terminal on the + side of the adder 513. Further, the adder 513 generates a voltage signal Os obtained by subtracting the voltage of the input terminal on the - side from the voltage of the input terminal on the + side and outputs to the comparator 514.

[0067] The comparator 514 outputs a modulation signal Ms obtained by pulse-modulating the voltage signal Os input from the adder 513. Specifically, the comparator 514 generates and outputs a modulation signal Ms that becomes an H level when the voltage value of the voltage signal Os input from the adder 513 rises to be equal to or higher than a prescribed threshold value Vthl and becomes an L level when the voltage value of the voltage signal Os falls to be lower than a prescribed threshold value Vth2. Here, the threshold values Vthl, Vth2 are set to be in a relationship of threshold value Vthl > threshold value Vth2.

[0068] The modulation signal Ms output from the comparator 514 is input to the gate driver 521 included in the gate drive circuit 520 and is also input to the gate driver 522 included in the gate drive circuit 520 via the inverter 515. That is, signals whose logic levels are in an exclusive relationship are input to the gate driver 521 and the gate driver 522. Here, the logic levels being in an exclusive relationship includes a case where the logic levels of the signals input to the gate driver 521 and the gate driver 522 do not become H levels at the same time. Therefore, the modulation circuit 510 can include a timing control circuit for controlling the timing of the modulation signal Ms input to the gate driver 521 and the signal obtained by inverting the logic level of the modulation signal Ms input to the gate driver 522 instead of or in addition to the inverter 515.

[0069] The gate drive circuit 520 includes the gate driver 521 and the gate driver 522. The gate driver 521 generates an amplification control signal Hgd by performing level shifting on the modulation signal Ms output from the comparator 514 and outputs from the terminal Hdr.

[0070] Specifically, a voltage is supplied to the high-side of the power supply voltage to the gate driver 521 via terminal Bst, and a voltage is supplied to the low-side via terminal Sw. Terminal Bst is connected to one end of capacitor C5 and the cathode of diode D1 for preventing reverse current. Terminal Sw is connected to the other end of capacitor C5. Additionally, the anode of diode D1 is connected to terminal Gvd. Furthermore, terminal Gvd is supplied with a voltage signal Vm, which is, for example, a 7.5V DC voltage output from a power supply circuit (not shown). That is, the anode of diode D1 is supplied with the voltage signal Vm. Therefore, the potential difference between terminal Bst and terminal Sw is approximately equal to the voltage value of the voltage signal Vm. As a result, the gate driver 521 generates an amplified control signal Hgd based on the input modulation signal Ms, whose voltage value relative to terminal Sw is increased by an amount corresponding to the voltage value of the voltage signal Vm, and outputs it from terminal Hdr.

[0071] Gate driver 522 operates at a lower potential than gate driver 521. Gate driver 522 generates an amplified control signal Lgd by level shifting the signal after the logic level of the modulation signal Ms output from comparator 514 is inverted by inverter 515, and outputs it from terminal Ldr.

[0072] Specifically, the high-order side of the power supply voltage of the gate driver 522 is supplied with a voltage signal Vm, and the low-order side is supplied with a ground potential via the terminal Gnd. Furthermore, the gate driver 522 outputs an amplified control signal Lgd from the terminal Ldr, based on the signal obtained by inverting the logic level of the input modulation signal Ms, with a voltage value increased relative to the terminal Gnd by an amount corresponding to the voltage value of the voltage signal Vm. Here, the ground potential refers to the reference potential of the drive circuit 50, for example, 0V.

[0073] The amplifier circuit 550 includes transistor M1 and transistor M2.

[0074] Transistor M1 is a surface-mount FET (Field Effect Transistor). The drain of transistor M1 is supplied with a voltage signal VHV as the power supply voltage for the amplifier circuit 550. This voltage signal VHV is, for example, a 42V DC voltage. Furthermore, the gate of transistor M1 is electrically connected to one end of resistor R1, and the other end of resistor R1 is electrically connected to the terminal Hdr of integrated circuit 500. That is, the gate of transistor M1 is supplied with the amplification control signal Hgd. Additionally, the source of transistor M1 is electrically connected to the terminal Sw of integrated circuit 500.

[0075] The transistor M2 is a surface-mounted FET, and the drain of the transistor M2 is electrically connected to the terminal Sw of the integrated circuit 500. That is, the drain of the transistor M2 is electrically connected to the source of the transistor Ml. The gate of the transistor M2 is electrically connected to one end of the resistor R2, and the other end of the resistor R2 is electrically connected to the terminal Ldr of the integrated circuit 500. That is, the gate of the transistor M2 is input with the amplification control signal Lgd. In addition, the source of the transistor M2 is supplied with the ground potential.

[0076] Furthermore, when the drain and the source of the transistor Ml are controlled to be non-conductive and the drain and the source of the transistor M2 are controlled to be conductive, the potential of the node connected to the terminal Sw becomes the ground potential. Therefore, the terminal Bst is supplied with the potential of the sum of the voltage value of the voltage signal VHV and the voltage value of the voltage signal Vm. That is, the gate driver 521 that drives the transistor Ml generates the amplification control signal Lgd having the L level of the ground potential and the H level of the voltage value of the voltage signal Vm, and outputs it to the gate of the transistor Ml, independently of the operation of the transistor Ml and the transistor M2.

[0077] On the other hand, the gate driver 522 that drives the transistor M2 generates the amplification control signal Lgd having the L level of the ground potential and the H level of the voltage value of the voltage signal Vm, and outputs it to the gate of the transistor M2, independently of the operation of the transistor Ml and the transistor M2.

[0078] The amplification circuit 550 configured as described above generates the amplification modulation signal AMs at the connection point of the source of the transistor Ml and the drain of the transistor M2, the amplification modulation signal AMs being a signal in which the modulation signal Ms is amplified in accordance with the voltage signal VHV. Furthermore, the amplification circuit 550 outputs the generated amplification modulation signal AMs to the smoothing circuit 560, and outputs it to the frequency measuring circuit 54.

[0079] Here, the capacitor C7 is provided on the transmission path of the voltage signal VHV of the transmission input amplification circuit 550. Specifically, one end of the capacitor C7 is electrically connected to the transmission path of the voltage signal VHV and the drain of the transistor Ml, and the other end of the capacitor C7 is supplied with a ground potential. Thus, the possibility of the voltage value of the voltage signal VHV of the input amplification circuit 550 varying is reduced, and the possibility of noise being superimposed on the voltage signal VHV is reduced, as a result of which the waveform accuracy of the amplified modulation signal AMs output from the amplification circuit 550 is improved. Therefore, an electrolytic capacitor of high withstand voltage and large capacity is used. Further, the capacitor C7 can be provided corresponding to one drive circuit 50 or can be provided corresponding to a plurality of drive circuits 50.

[0080] The smoothing circuit 560 generates a drive signal COM by demodulating the amplified modulation signal AMs output from the amplification circuit 550 and outputs the drive signal COM from the drive circuit 50. The smoothing circuit 560 includes an inductor LI and a capacitor CI. One end of the inductor LI is connected to one end of the capacitor CI. The other end of the inductor LI is input with the amplified modulation signal AMs. In addition, the other end of the capacitor CI is supplied with a ground potential. That is, in the smoothing circuit 560, the inductor LI and the capacitor CI constitute a low pass filter. Further, the smoothing circuit 560 demodulates by smoothing the amplified modulation signal AMs using the low pass filter and outputs the demodulated signal as the drive signal COM. That is, the drive circuit 50 outputs the drive signal COM from one end of the inductor LI and one end of the capacitor CI included in the smoothing circuit 560.

[0081] The feedback circuit 570 includes a resistor R3 and a resistor R4. One end of the resistor R3 is supplied with the drive signal COM, and the other end is connected to a terminal Vfb and one end of the resistor R4. The other end of the resistor R4 is supplied with the voltage signal VHV. Thus, the drive signal COM after passing through the feedback circuit 570 is fed back to the terminal Vfb in a state of being pulled up using the voltage value of the voltage signal VHV.

[0082] The feedback circuit 572 includes capacitors C2, C3, C4, and resistors R5, R6. One end of the capacitor C2 is supplied with the drive signal COM, and the other end is connected to one end of the resistor R5 and one end of the resistor R6. The other end of the resistor R5 is supplied with a ground potential. Thus, the capacitor C2 and the resistor R5 function as a high pass filter. In addition, the other end of the resistor R6 is connected to one end of the capacitor C4 and one end of the capacitor C3. The other end of the capacitor C3 is supplied with a ground potential. Thus, the resistor R6 and the capacitor C3 function as a low pass filter. That is, the feedback circuit 572 includes a high pass filter and a low pass filter, and functions as a band pass filter that passes a signal of a prescribed frequency band included in the drive signal COM.

[0083] In addition, the other end of the capacitor C4 is connected to the terminal Ifb of the integrated circuit 500. Thus, a signal in which a direct current component is cut out from the high frequency component of the drive signal COM that has passed through the feedback circuit 572 functioning as a band pass filter is fed back to the terminal Ifb.

[0084] The drive signal COM is a signal in which the amplified modulation signal AMs based on the base drive signal dO is smoothed by the smoothing circuit 560. In addition, the drive signal COM is fed back to the adder 512 after being integrated and subtracted via the terminal Vfb. Thus, the drive circuit 50 self-oscillates at a frequency determined by the delay of the feedback and the transfer function of the feedback. However, the amount of delay of the feedback path via the terminal Vfb is large, and thus, it is not always possible to increase the frequency of the self-oscillation to a degree at which the accuracy of the drive signal COM can be sufficiently ensured by feedback via the terminal Vfb. Thus, by providing a path that feeds back the high frequency component of the drive signal COM via the terminal Ifb separately from the path via the terminal Vfb, the delay when viewed from the entire circuit is reduced. Thus, compared to when there is no path via the terminal Ifb, it is possible to increase the frequency of the voltage signal Os to a degree at which the accuracy of the drive signal COM can be sufficiently ensured.

[0085] As described above, the drive circuit 50 includes a modulation circuit 510 that outputs a modulation signal Ms that modulates a base drive signal dO that is the basis of a drive signal COM, an amplification circuit 550 that outputs an amplified modulation signal AMs that amplifies the modulation signal Ms, a smoothing circuit 560 that outputs a drive signal COM that smoothes the amplified modulation signal AMs, and feedback circuits 570, 572 that feed back the drive signal COM to the modulation circuit 510. Also, the drive circuit 50 generates the drive signal COM by D-stage amplifying an analog signal after digitally / analog- converting the input base drive signal dO, and outputs the generated drive signal COM. That is, the drive circuit 50 includes a D-stage amplification circuit, and the print head 20 receives the drive signal COM output from the drive circuit 50 including the D-stage amplification circuit and ejects ink.

[0086] In addition, the frequency measurement circuit 54 detects the frequency of the amplified modulation signal AMs output from the amplification circuit 550. Also, the frequency measurement circuit 54 generates a frequency determination signal Fm that becomes an H level for a certain period when the detected frequency of the amplified modulation signal AMs becomes a maximum value, and outputs it to the control circuit 100.

[0087] Here, the relationship between the frequency of the amplified modulation signal AMs and the voltage value of the drive signal COM will be described.

[0088] As described above, the drive circuit 50 of the present embodiment self-oscillates at a frequency determined by the delay of the feedback of the feedback circuits 570, 572 and the transfer function of the feedback. The frequency of the self-oscillation of this drive circuit 50 is the switching frequency of the amplification circuit 550, and corresponds to the frequency of the amplified modulation signal AMs. In the case of such a self-oscillation circuit, from the viewpoint of circuit efficiency, waveform accuracy of the output signal, and stability of the operation, the frequency of the self-oscillation becomes a maximum value near the average voltage between the maximum voltage and the minimum voltage of the output signal, and decreases as the voltage value rises or the voltage value decreases.

[0089] In view of the frequency characteristics of such a drive circuit 50, the frequency measurement circuit 54 detects the frequency of the amplified modulation signal AMs, generates a frequency determination signal Fm that becomes an H level at the instant when the detected frequency turns from rising to falling and continues for a certain period, and outputs it to the control circuit 100. In this case, the frequency measurement circuit 54 can also detect the frequency of the amplified modulation signal AMs, calculate the moving average of the detected frequency, generate a frequency determination signal Fm that becomes an H level at the instant when the calculated moving average turns from rising to falling, and output it to the control circuit 100.

[0090] Further, the frequency measurement circuit 54 can also be controlled to not output the frequency determination signal Fm at an H level when the voltage value of the drive signal COM is not within the prescribed range, or when the frequency of the amplified modulation signal AMs is lower than the prescribed frequency. Thereby, the detection accuracy of the maximum value of the frequency of the amplified modulation signal AMs in the frequency measurement circuit 54 is improved.

[0091] 4. Configuration of drive signal selection circuit

[0092] Next, the configuration and operation of the drive signal selection circuit 200 will be described. As described above, the drive signal selection circuit 200 generates the drive signal VOUT by selecting or deselecting the signal waveform of the drive signal COM, and outputs it to one end of the piezoelectric element 60.

[0093] Figure 4 is a diagram showing the configuration of the drive signal selection circuit 200. As shown in Figure 4 the drive signal selection circuit 200 has a selection control circuit 210 and selection circuits 230[1] to 230[m] corresponding to the piezoelectric elements 60[1] to 60[m], respectively.

[0094] The clock signal SCK, the latch signal LAT, the changeover signal CH, and the head control signal DI are input to the selection control circuit 210. The selection control circuit 210 generates selection signals S[1] to S[m] for switching whether to output the signal waveform included in the drive signal COM as the drive signal VOUT, based on the input clock signal SCK, the latch signal LAT, the changeover signal CH, and the head control signal DI. The selection signals S[1] to S[m] generated by the selection control circuit 210 are input to the corresponding selection circuits 230[1] to 230[m]. The selection circuits 230[1] to 230[m] generate the drive signals VOUT[1] to VOUT[m] corresponding to the piezoelectric elements 60[1] to 60[m] by selecting or deselecting the signal waveform of the drive signal COM based on the input selection signals S[1] to S[m], and output them to the corresponding piezoelectric elements 60[1] to 60[m]. Here, the selection circuits 230[1] to 230[m] are all of the same configuration, and the selection circuit 230[1] to 230[m] corresponding to the piezoelectric element 60 among the piezoelectric elements 60[1] to 60[m] will be referred to as the selection circuit 230. At this time, the selection circuit 230 will be described as selecting or deselecting the signal waveform of the drive signal COM based on the selection signal S among the selection signals S[1] to S[m].

[0095] The operation of the selection control circuit 210 will be described in detail. First, a summary of the latch signal LAT, the conversion signal CH, the clock signal SCK, and the head control signal DI input to the selection control circuit 210 will be described. Figure 5 is a diagram for explaining the relationship between the latch signal LAT, the conversion signal CH, the clock signal SCK, and the head control signal DI and the selection signal S.

[0096] The latch signal LAT is a pulse signal based on a signal output from the linear encoder 90 indicating the scanning position of the print head 20, and defines the period tp in which the print head 20 forms dots on the medium P. The conversion signal CH is a pulse signal that defines the switching timing of whether to supply the signal waveform included in the drive signal COM to the piezoelectric element 60, and divides the period tp into the periods tl, t2, t3. The drive signal selection circuit 200 selects or deselects the signal waveform included in the drive signal COM in each of the periods tl, t2, t3 obtained by dividing the period tp defined by the latch signal LAT with the conversion signal CH, and thereby generates the drive signal VOUT and outputs it to the piezoelectric element 60.

[0097] In addition, the head control signal DI serially includes the ejection control signal SI and the waveform selection signal SP. The ejection control signal SI independently defines the ejection amount of ink ejected under the drive of the piezoelectric element 60 for each of the piezoelectric elements 60[1] to 60[m]. In addition, the waveform selection signal SP defines the relationship between the logic level of the selection signal S output in each of the periods tl, t2, t3 and the ejection control signal SI.

[0098] Furthermore, as shown in Figure 5 the head control signal DI is input to the selection control circuit 210 in synchronization with the clock signal SCK within the period tp before the rising of the latch signal LAT. At this time, the head control signal DI input to the selection control circuit 210 is held in a register corresponding to each of the piezoelectric elements 60[1] to 60[m]. Furthermore, the head control signal DI held in the register is latched together with the rising edge of the latch signal LAT. That is, the head control signal DI held in the register is latched together at the timing of the start of the period tp. The selection control circuit 210 generates the selection signal S corresponding to each of the periods tl, t2, t3 in the period tp after the rising of the latch signal LAT from the head control signal DI latched together, and outputs it to the selection circuit 230.

[0099] Here, the head control signal DI including the ejection control signal SI and the waveform selection signal SP will be described in detail. Figure 6 is a diagram showing an example of the data configuration of the head control signal DI. As Figure 6As shown, the head control signal DI includes the ejection control signal SI and the waveform selection signal SP.

[0100] The ejection control signal SI is a signal that specifies the ejection amount of ink ejected under the drive of the piezoelectric elements 60, and includes upper ejection data SIH and lower ejection data SIL. That is, in the ejection control signal SI, 2-bit data of the upper ejection data SIH and the lower ejection data SIL for controlling the drive of the piezoelectric elements 60[1] to 60[m] are included corresponding to the piezoelectric elements 60[1] to 60[m], respectively.

[0101] Specifically, the ejection control signal SI includes m-bit upper ejection data SIH corresponding to the piezoelectric elements 60[1] to 60[m] in the order of the upper ejection data SIH corresponding to the piezoelectric element 60[m], the upper ejection data SIH corresponding to the piezoelectric element 60[m-1],..., the upper ejection data SIH corresponding to the piezoelectric element 60[1], and immediately after the upper ejection data SIH, m-bit lower ejection data SIL corresponding to the piezoelectric elements 60[1] to 60[m] in the order of the lower ejection data SIL corresponding to the piezoelectric element 60[m], the lower ejection data SIL corresponding to the piezoelectric element 60[m-1],..., the lower ejection data SIL corresponding to the piezoelectric element 60[1]. That is, the ejection control signal SI is a 2m-bit signal that serially includes m-bit upper ejection data SIH corresponding to the piezoelectric elements 60[m] to 60[1] and m-bit lower ejection data SIL corresponding to the piezoelectric elements 60[m] to 60[1]. Also, the ejection amount of ink ejected under the drive of the piezoelectric element 60[i] (i is any one of 1 to m) is specified by 2 bits of the upper ejection data SIH corresponding to the piezoelectric element 60[i] and the lower ejection data SIL corresponding to the piezoelectric element 60[i].

[0102] Here, in the following description, the upper ejection data SIH corresponding to the piezoelectric element 60[i] is sometimes referred to as upper ejection data SIHi, and the lower ejection data SIL corresponding to the piezoelectric element 60[i] is sometimes referred to as lower ejection data SILi. Further, in the following description, the upper ejection data SIH and the lower ejection data SIL corresponding to the piezoelectric element 60 are sometimes collectively referred to as ejection data [SIH, SIL], and the upper ejection data SIHi and the lower ejection data SILi corresponding to the piezoelectric element 60[i] are sometimes collectively referred to as ejection data [SIHi, SILi]. That is, the ejection amount of ink ejected under the drive of the piezoelectric element 60[i] is specified by the ejection data [SIHi, SILi].

[0103] The waveform selection signal SP is a signal for specifying the drive pattern of the piezoelectric element 60 corresponding to the ejection data [SIH, SIL] in each of the periods tl, t2, t3, and specifies the logic level of the selection signal S output in each of the periods tl, t2, t3 corresponding to the ejection data [SIH, SIL]. The waveform selection signal SP in the present embodiment is a 12-bit signal including the setting information SP00 to SP03, SP10 to SP13, and SP20 to SP23.

[0104] Specifically, the waveform selection signal SP serially includes the setting information SP00 to SP03, the setting information SP10 to SP13, and the setting information SP20 to SP23 in the order of the setting information SP23, SP22, SP21, SP20, SP13, SP12, SP11, SP10, SP03, SP02, SP01, and SP00, in which the setting information SP00 to SP03 specifies the drive pattern of the piezoelectric element 60 in the period tl determined by the ejection data [SIH, SIL], the setting information SP10 to SP13 specifies the drive pattern of the piezoelectric element 60 in the period t2 determined by the ejection data [SIH, SIL], and the setting information SP20 to SP23 specifies the drive pattern of the piezoelectric element 60 in the period t3 determined by the ejection data [SIH, SIL]. Further, the waveform selection signal SP is not limited to a 12-bit signal, and can be a signal of 12 bits or more or a signal of 12 bits or less, according to the number of periods divided by the conversion signal CH or the number of drive patterns of the piezoelectric element 60 specified by the ejection control signal SI, and the period tp.

[0105] Returning to Figure 4 , the selection control circuit 210 has a control logic circuit 260 and selection signal output sections 270[1] to 270[m] provided corresponding to the piezoelectric elements 60[1] to 60[m]. Further, the selection control circuit 210 generates the selection signals S[1] to S[m] corresponding to the piezoelectric elements 60[1] to 60[m], respectively, from the head control signal DI transmitted in synchronization with the clock signal SCK at the timing specified by the inputted latch signal LAT and the conversion signal CH, and outputs to the corresponding selection circuits 230[1] to 230[m].

[0106] The control logic circuit 260 includes an SP register group 261 and a selection control signal generating section 262. The SP register group 261 includes a plurality of registers connected in series and constitutes a so-called shift register that sequentially transmits a head control signal DI input in synchronization with a clock signal SCK to a register at a subsequent stage. Further, when the supply of the clock signal SCK is stopped, the setting information SP00 to SP23 contained in the waveform selection signal SP in the head control signal DI is held in the SP register group 261.

[0107] The selection control signal generating section 262 latches the setting information SP00 to SP23 held in the SP register group 261 at the rising edge of the latch signal LAT. Further, the selection control signal generating section 262 generates selection control signals Q0, Q1, Q2 by interpreting the latched setting information SP00 to SP23 and outputs them to the decoders 226 possessed by the selection signal output sections 270[1] to 270[m], respectively. The selection control signal Q0 contains the setting information SP00, SP01, SP02, SP03 and specifies the logic level of the selection signal S output from the selection control circuit 210 during the period t1. The selection control signal Q1 contains the setting information SP10, SP11, SP12, SP13 and specifies the logic level of the selection signal S output from the selection control circuit 210 during the period t2. The selection control signal Q2 contains the setting information SP20, SP21, SP22, SP23 and specifies the logic level of the selection signal S output from the selection control circuit 210 during the period t3. Here, in the following description, the selection control signal Q0 containing the setting information SP00, SP01, SP02, SP03 will be sometimes referred to as the selection control signal Q0[SP00, SP01, SP02, SP03], the selection control signal Q1 containing the setting information SP10, SP11, SP12, SP13 will be sometimes referred to as the selection control signal Q1[SP10, SP11, SP12, SP13], and the selection control signal Q2 containing the setting information SP20, SP21, SP22, SP23 will be sometimes referred to as the selection control signal Q2[SP20, SP21, SP22, SP23].

[0108] The selection signal output sections 270[1] to 270[m] each have a first register 222a, a second register 222b, a first latch circuit 224a, a second latch circuit 224b, and a decoder 226.

[0109] The second registers 222b contained in the selection signal output sections 270[1] to 270[m], respectively, are connected in series at a subsequent stage of the SP register group 261 including a plurality of registers, and the first registers 222a contained in the selection signal output sections 270[1] to 270[m], respectively, are connected in series at a subsequent stage of the m second registers 222b connected in series.

[0110] Specifically, the second register 222b included in the selection signal output section 270[1] is connected at the rear stage of the SP register group 261, and the second registers 222b included in the selection signal output sections 270[2] to 270[m] are connected in series at the rear stage of the second register 222b included in the selection signal output section 270[1] in order. Furthermore, the first register 222a included in the selection signal output section 270[1] is connected at the rear stage of the second register 222b included in the selection signal output section 270[m]. In addition, the first registers 222a included in the selection signal output sections 270[2] to 270[m] are connected in series at the rear stage of the first register 222a included in the selection signal output section 270[1] in order.

[0111] That is, the SP register group 261, the m second registers 222b included in each of the selection signal output sections 270[1] to 270[m], and the m first registers 222a included in each of the selection signal output sections 270[1] to 270[m] constitute a shift register. Furthermore, the head control signal DI input to the SP register group 261 is transmitted to the rear stage in the order of the m second registers 222b included in each of the selection signal output sections 270[1] to 270[m] and the m first registers 222a included in each of the selection signal output sections 270[1] to 270[m] in synchronization with the clock signal SCK. Then, by stopping the supply of the clock signal SCK, the lower bit ejection data SILi corresponding to the piezoelectric element 60[i] is held in the second register 222b included in the selection signal output section 270[i], and the upper bit ejection data SIHi corresponding to the piezoelectric element 60[i] is held in the first register 222a included in the selection signal output section 270[i].

[0112] The upper emission data SIH held in the first register 222a of each of the selection signal output sections 270[1] to 270[m] is latched by the corresponding first latch circuit 224a at the rising edge of the latch signal LAT, and the lower emission data SIl held in the second register 222b of each of the selection signal output sections 270[1] to 270[m] is latched by the corresponding second latch circuit 224b at the rising edge of the latch signal LAT. Further, the first latch circuit 224a outputs the latched upper emission data SIH as a latch data LTa to the decoder 226, and the second latch circuit 224b outputs the latched lower emission data SIl as a latch data LTb to the decoder 226.

[0113] Here, in the following description, the latch data LTa output from the first latch circuit 224a of the selection signal output section 270[i] is sometimes referred to as a latch data LTai, and the latch data LTb output from the second latch circuit 224b of the selection signal output section 270[i] is sometimes referred to as a latch data LTbi. In addition, the latch data LTa and LTb are sometimes collectively referred to as latch data [LTa, LTb], and the latch data LTai and LTbi corresponding to the selection signal output section 270[i] are sometimes collectively referred to as latch data [LTai, LTbi].

[0114] The decoder 226 of each of the selection signal output sections 270[1] to 270[m] has the selection control signals Q0[SP00, SP01, SP02, SP03], the selection control signals Q1[SP10, SP11, SP12, SP13], and the selection control signals Q2[SP20, SP21, SP22, SP23] output from the selection control signal generation section 262 commonly input thereto, and has the latch data [LTa, LTb] output from the corresponding first latch circuit 224a and the second latch circuit 224b input thereto. That is, the decoder 226 of the selection signal output section 270[i] has the selection control signals Q0[SP00, SP01, SP02, SP03], the selection control signals Q1[SP10, SP11, SP12, SP13], and the selection control signals Q2[SP20, SP21, SP22, SP23] output from the selection control signal generation section 262 and the latch data [LTai, LTbi] corresponding to the emission data [SIHi, SIl i] input thereto. Further, the decoder 226 of the selection signal output section 270[i] generates the selection signal S[i] by decoding the latch data [LTai, LTbi] in accordance with the selection control signals Q0, Q1, and Q2, and outputs the selection signal S[i] to the selection circuit 230[i].

[0115] Figure 7is a view showing the decoding contents of the decoder 226 based on the selection control signals Q0, Q1, Q2. As shown in the view, the decoder 226 outputs the selection signal S of the logic level specified by the selection control signal Q0 [SP00, SP01, SP02, SP03] during the period tl, outputs the selection signal S of the logic level specified by the selection control signal Q1 [SP10, SP11, SP12, SP13] during the period t2, and outputs the selection signal S of the logic level specified by the selection control signal Q2 [SP20, SP21, SP22, SP23] during the period t3. Figure 7

[0116] Specifically, when the latch data [LTa, LTb] = [1, 1] is input to the decoder 226, the decoder 226 outputs the logic level of the set information SP00 as the selection signal S during the period tl, outputs the logic level of the set information SP10 as the selection signal S during the period t2, and outputs the logic level of the set information SP20 as the selection signal S during the period t3, in accordance with the contents specified by the selection control signals Q0, Q1, Q2. Similarly, when the latch data [LTa, LTb] = [1, 0] is input to the decoder 226, the decoder 226 outputs the logic level of the set information SP01 as the selection signal S during the period tl, outputs the logic level of the set information SP11 as the selection signal S during the period t2, and outputs the logic level of the set information SP21 as the selection signal S during the period t3, in accordance with the contents specified by the selection control signals Q0, Q1, Q2. Similarly, when the latch data [LTa, LTb] = [0, 1] is input to the decoder 226, the decoder 226 outputs the logic level of the set information SP02 as the selection signal S during the period tl, outputs the logic level of the set information SP12 as the selection signal S during the period t2, and outputs the logic level of the set information SP22 as the selection signal S during the period t3, in accordance with the contents specified by the selection control signals Q0, Q1, Q2. Similarly, when the latch data [LTa, LTb] = [0, 0] is input to the decoder 226, the decoder 226 outputs the logic level of the set information SP03 as the selection signal S during the period tl, outputs the logic level of the set information SP13 as the selection signal S during the period t2, and outputs the logic level of the set information SP23 as the selection signal S during the period t3, in accordance with the contents specified by the selection control signals Q0, Q1, Q2.

[0117] ​As described above, the selection control circuit 210 outputs selection signals S[l]-S[m] for controlling the states of the selection circuits 230[l]-230[m] corresponding to the piezoelectric elements 60[l]-60[m], respectively, in accordance with the clock signal SCK, the latch signal LAT, the conversion signal CH, and the head control signal DI.

[0118] Next, the configuration of the selection circuits 230[l]-230[m] will be described. Here, the selection circuits 230[l]-230[m] are of the same configuration. Therefore, the selection circuits 230[l]-230[m] will be sometimes simply referred to as the selection circuit 230 without distinguishing the selection circuits 230[l]-230[m]. Also, the description will be made with the selection signal S of the selection signals S[l]-S[m] being input to the selection circuit 230.

[0119] Figure 8 is a view showing the configuration of the selection circuit 230 corresponding to the piezoelectric element 60. As shown in Figure 8 , the selection circuit 230 has an inverter 232 as a NOT circuit and a transmission gate 234.

[0120] The selection signal S output from the selection control circuit 210 is input to the positive control terminal of the transmission gate 234 to which no circular mark is attached, and, on the other hand, is logically inverted by the inverter 232 and is input to the negative control terminal of the transmission gate 234 to which a circular mark is attached. Also, the input terminal of the transmission gate 234 is supplied with the drive signal COM. Specifically, the transmission gate 234 makes the input terminal and the output terminal conductive when the input selection signal S is at the H level, and makes the input terminal and the output terminal non-conductive when the input selection signal S is at the L level. Also, the drive signal VOUT is output from the output terminal of the transmission gate 234.

[0121] As described above, the drive signal selection circuit 200 in the present embodiment selects or deselects the signal waveform of the drive signal COM in accordance with the input clock signal SCK, the latch signal LAT, the conversion signal CH, and the head control signal DI, thereby generating the drive signals VOUT[l]-VOUT[m] corresponding to the piezoelectric elements 60[l]-60[m], respectively, and outputting to the corresponding piezoelectric elements 60[l]-60[m].

[0122] Here, an example of the specific operation of the drive signal selection circuit 200 will be described. The drive signal selection circuit 200 generates the drive signal VOUT by selecting or deselecting the signal waveform of the drive signal COM, and outputs to one end of the piezoelectric element 60. Therefore, when the example of the specific operation of the drive signal selection circuit 200 is described, the specific example of the signal waveform of the drive signal COM input to the drive signal selection circuit 200 will be described.

[0123] Figure 9 is a graph showing an example of a signal waveform of the drive signal COM. As shown in Figure 9 , the drive signal COM is a signal including signal waveforms that make the trapezoidal waveforms Adp, Bdp, and Cdp continuous, in which the trapezoidal waveform Adp is configured in a period tl from when the latch signal LAT rises until when the changeover signal CH rises, the trapezoidal waveform Bdp is configured in a period t2 from when the changeover signal CH rises until when the changeover signal CH next rises, and the trapezoidal waveform Cdp is configured in a period t3 from when the changeover signal CH rises until when the latch signal LAT rises.

[0124] The trapezoidal waveform Adp is a signal waveform that drives the piezoelectric element 60 in such a manner that a prescribed amount of ink is ejected from the corresponding nozzle when supplied to the piezoelectric element 60, the trapezoidal waveform Bdp is a signal waveform that drives the piezoelectric element 60 in such a manner that less than the prescribed amount of ink is ejected from the corresponding nozzle when supplied to the piezoelectric element 60, and the trapezoidal waveform Cdp is a signal waveform that drives the piezoelectric element 60 in such a manner that no ink is ejected from the corresponding nozzle even when supplied to the piezoelectric element 60. Here, the trapezoidal waveform Cdp is a signal waveform for causing the ink near the orifice portion of the nozzle to vibrate moderately so as to prevent an increase in the viscosity of the ink. In the following description, the action of causing the ink near the orifice portion of the nozzle to vibrate when the trapezoidal waveform Cdp is supplied to the piezoelectric element 60 will sometimes be referred to as micro-vibration. In addition, in the following description, the amount of ink ejected when the trapezoidal waveform Adp is supplied to the piezoelectric element 60 will sometimes be referred to as a large amount, and the amount of ink ejected when the trapezoidal waveform Bdp is supplied to the piezoelectric element 60 will sometimes be referred to as a small amount.

[0125] In addition, the voltage values of the start timing and the end timing of each of the trapezoidal waveforms Adp, Bdp, and Cdp are all the voltage Vc. That is, the trapezoidal waveforms Adp, Bdp, and Cdp each start with the voltage Vc and end with the voltage Vc. Furthermore, the period tp constituted by the periods tl, t2, and t3 corresponds to a dot formation period in which new dots are formed on the medium P.

[0126] Figure 10This diagram illustrates an example of the head control signal DI, which is input to the drive signal selection circuit 200. Here, the ejection control signal SI included in the head control signal DI specifies the amount of ink ejected under the drive of the piezoelectric element 60. Therefore, the logic level of the ejection control signal SI changes appropriately during printing when the liquid ejection device 1 ejects ink to form the desired image on the medium P. That is, the logic level of the ejection data [SIH, SIL] included in the ejection control signal SI changes to either 0 or 1 depending on the amount of ink ejected. In other words, the logic level of the ejection data [SIH, SIL] included in the ejection control signal SI changes periodically by tp according to the image formed on the medium P. Therefore, in Figure 10 The diagram only shows the specific logic level of the waveform selection signal SP, while omitting the actual logic level of the waveform selection signal SP.

[0127] like Figure 10 As shown, the drive signal selection circuit 200 receives a header control signal DI containing setting information SP00, SP01, SP02, SP03, SP10, SP11, SP12, SP13, SP20, SP21, SP22, and SP23, which are respectively "1", "0", "0", "0", "0", "1", "0", "0", "0", "1", "0", "0", "1", and "0". Therefore, the selection control signal generation unit 262 included in the control logic circuit 260 generates selection control signals Q0[SP00, SP01, SP02, SP03] = [1, 0, 0, 0], selection control signals Q1[SP10, SP11, SP12, SP13] = [0, 1, 0, 0], and selection control signals Q2[SP20, SP21, SP22, SP23] = [0, 0, 1, 0] based on the waveform selection signals SP, and outputs them to the decoder 226.

[0128] Figure 11 This diagram illustrates a specific example of the decoding content of the decoder 226 when a head control signal DI containing the aforementioned waveform selection signal SP is input to the drive signal selection circuit 200. Furthermore, the decoder 226 of this embodiment will be described as outputting a selection signal S at level H when the logic level of the corresponding setting information SP23-SP20, SP13-SP10, and SP03-SP00 is "1", and outputting a selection signal S at level L when the logic level of the corresponding setting information SP23-SP20, SP13-SP10, and SP03-SP00 is "0".

[0129] like Figure 11As shown, when latched data [LTa, LTb] = [1, 1] corresponding to the ejected data [SIH, SIL] = [1, 1] is input to decoder 226, decoder 226 outputs selection signal S that is at H, L, L level during periods t1, t2, and t3. Furthermore, when latched data [LTa, LTb] = [1, 0] corresponding to the ejected data [SIH, SIL] = [1, 0] is input to decoder 226, decoder 226 outputs selection signal S that is at L, H, L level during periods t1, t2, and t3. Additionally, when latched data [LTa, LTb] = [0, 1] corresponding to the ejected data [SIH, SIL] = [0, 1] is input to decoder 226, decoder 226 outputs selection signal S that is at L, L, H level during periods t1, t2, and t3. Additionally, when inputting latched data [LTa, LTb] = [0, 0] corresponding to the ejected data [SIH, SIL] = [0, 0] into the decoder 226, the decoder 226 outputs a selection signal S that is at level L, L, L during the periods t1, t2, and t3.

[0130] Figure 12 It means that it was supplied Figure 11 The diagram shows an example of the drive signal VOUT output from the selection circuit 230 when the selection signal S is shown.

[0131] like Figure 12 As shown, when latched data [LTa, LTb] = [1, 1] is input to decoder 226, the logic level of selection signal S is H level during period t1, L level during period t2, and L level during period t3. Therefore, the input and output terminals of selection circuit 230 are connected during period t1, not connected during period t2, and not connected during period t3. As a result, selection circuit 230 outputs a drive signal VOUT that is a trapezoidal waveform Adp during period t1, a constant voltage Vc during period t2, and a constant voltage Vc during period t3.

[0132] At this time, driven by the piezoelectric element 60, a large amount of ink is ejected during period t1, and no ink is ejected during period t2 and period t3. Therefore, a large amount of ink falls onto the medium P, thus forming large dots on the medium P.

[0133] Further, when the latch data [LTa, LTb] = [1, 0] is input to the decoder 226, the logic level of the selection signal S becomes the L level during the period tl, the H level during the period t2, and the L level during the period t3. Therefore, the input terminal and the output terminal of the selection circuit 230 are not conducted during the period tl, are conducted during the period t2, and are not conducted during the period t3. As a result, the selection circuit 230 outputs the drive signal VOUT which is constant at the voltage Vc during the period tl, becomes the trapezoidal waveform Bdp during the period t2, and is constant at the voltage Vc during the period t3.

[0134] At this time, by the drive of the piezoelectric element 60, ink is not ejected during the period tl, a small amount of ink is ejected during the period t2, and ink is not ejected during the period t3. Therefore, the small amount of ink lands on the medium P, thereby forming a small dot on the medium P.

[0135] Further, when the latch data [LTa, LTb] = [0, 1] is input to the decoder 226, the logic level of the selection signal S becomes the L level during the period tl, the L level during the period t2, and the H level during the period t3. Therefore, the input terminal and the output terminal of the selection circuit 230 are not conducted during the period tl, are not conducted during the period t2, and are conducted during the period t3. As a result, the selection circuit 230 outputs the drive signal VOUT which is constant at the voltage Vc during the period tl, is constant at the voltage Vc during the period t2, and becomes the trapezoidal waveform Cdp during the period t3.

[0136] At this time, by the drive of the piezoelectric element 60, ink is not ejected during the period tl, ink is not ejected during the period t2, and ink is not ejected during the period t3. Therefore, ink does not land on the medium P, thereby not forming a dot on the medium P, and performing a micro-vibration.

[0137] Further, when the latch data [LTa, LTb] = [0, 0] is input to the decoder 226, the logic level of the selection signal S becomes the L level during the period tl, the L level during the period t2, and the L level during the period t3. Therefore, the input terminal and the output terminal of the selection circuit 230 are not conducted during the period tl, are not conducted during the period t2, and are not conducted during the period t3. As a result, the selection circuit 230 outputs the drive signal VOUT which is constant at the voltage Vc during the period tl, is constant at the voltage Vc during the period t2, and is constant at the voltage Vc during the period t3. At this time, by the drive of the piezoelectric element 60, ink is not ejected during the period tl, ink is not ejected during the period t2, and ink is not ejected during the period t3. Therefore, ink does not land on the medium P, thereby not forming a dot on the medium P. At this time, ink near the opening portion of the nozzle corresponding to the piezoelectric element 60 also does not perform a micro-vibration.

[0138] As described above, the ejection module 22 of the present embodiment includes a plurality of piezoelectric elements 60, and the drive signal selection circuit 200 has a plurality of selection circuits 230 that switch whether to supply the drive signal VOUT based on the drive signal COM to the plurality of piezoelectric elements 60 included in the ejection module 22. Also, in the drive signal selection circuit 200, the selection circuit 230 outputs the drive signal VOUT for controlling to be on during the period tl, and to be off during the periods t2, t3, thereby forming a large dot on the medium P, the selection circuit 230 outputs the drive signal VOUT for controlling to be on during the period t2, and to be off during the periods tl, t2, thereby forming a small dot on the medium P, the selection circuit 230 outputs the drive signal VOUT for controlling to be on during the period t3, and to be off during the periods tl, t2, thereby not forming a dot on the medium P and performing a micro-vibration, and the selection circuit 230 outputs the drive signal VOUT for controlling to be off during all of the periods tl to t3, thereby not forming a dot on the medium P nor performing a micro-vibration.

[0139] Here, the drive signal VOUT output by the drive signal selection circuit 200 is a signal waveform in which any one of the trapezoidal waveforms Adp, Bdp, Cdp included in the drive signal COM is selected, and a signal waveform that is constantly the voltage Vc held by the capacitance component of the piezoelectric element 60 to which the drive signal VOUT is supplied are continuous. That is, the drive signal VOUT output by the drive signal selection circuit 200 is synonymous with the drive signal VOUT supplied to the piezoelectric element 60.

[0140] 5. Configuration of the ejection module 22 of the print head 20

[0141] Next, the structure of the ejection module 22 of the print head 20 will be described. Figure 13 is an exploded perspective view showing the structure of the ejection module 22, Figure 14 is a plan view of the ejection module 22, Figure 15 is a sectional view showing the IV-IV section shown in Figure 14 is a sectional view showing the IV-IV section shown in Figure 16 is a sectional view showing the IV-IV section shown in Figure 15 is a detailed view of a main portion of Figure 17 is a sectional view showing the IV-IV section shown in Figure 14The sectional view of the VI-VI section is shown. Also, in explaining the structure of the print head 20, three spatial axes X, Y, Z orthogonal to each other are illustrated in each drawing. In the present embodiment, the directions along these axes are referred to as the X-axis direction, the Y-axis direction, and the Z-axis direction, and, in the case of determining the orientation, the positive direction is set to "+" and the negative direction is set to "-," and the directions of the arrows in each drawing are set to the + direction and the opposite direction of the arrows is set to the - direction in the direction expression. Also, the Z-axis direction indicates the vertical direction, the +Z direction indicates the vertical downward direction, and the -Z direction indicates the vertical upward direction. Furthermore, with respect to the three spatial axes X, Y, Z that are not limited to the positive direction and the negative direction, they are referred to as the X-axis, the Y-axis, and the Z-axis.

[0142] As shown in FIG. 1, the ejection module 22 ejects ink in the Z-axis direction, more specifically, in the +Z-axis direction. The ejection module 22 has, as constituent components, a pressure chamber substrate 310, a communication plate 315, a nozzle plate 320, a plastic substrate 345, a vibration plate 350 to be described later, a piezoelectric element 60 to be described later, a protection substrate 330, a housing member 340, and a wiring substrate 420. Figure 13

[0143] The pressure chamber substrate 310 is constituted, for example, of a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, or the like. As shown in FIG. 2, on the pressure chamber substrate 310, two rows of pressure chamber rows are arranged in the X-axis direction, the pressure chamber rows being a plurality of pressure chambers 312 arranged in the Y-axis direction. In other words, the ejection module 22 of the print head 20 has a plurality of pressure chambers 312, and the plurality of pressure chambers 312 form pressure chamber rows in which a plurality of pressure chambers 312 are arranged in the Y-axis direction. Here, sometimes the pressure chamber row on the +X direction side among the two rows of pressure chamber rows is referred to as a first pressure chamber row, and the pressure chamber row separated from the first pressure chamber row in the -X direction in the X-axis direction is referred to as a second pressure chamber row. Also, Figure 14 Figure 14 is a plan view of the ejection module 22, and illustrates the constitution of the periphery of the pressure chamber substrate 310, and the illustration of the protection substrate 330 and the housing member 340 is omitted.

[0144] Also, the plurality of pressure chambers 312 constituting each pressure chamber row are arranged on a straight line in the Y-axis direction in such a manner that the positions in the X-axis direction are the same. Pressure chambers 312 adjacent to each other in the Y-axis direction are divided by a partition wall 311 as shown in FIG. 3. Of course, the arrangement of the pressure chambers 312 is not particularly limited. For example, the arrangement of the plurality of pressure chambers 312 arranged in the Y-axis direction can also be a so-called staggered arrangement in which the positions of the pressure chambers 312 are staggered every other position in the X-axis direction. Figure 17

[0145] ​​​Further, the pressure chamber 312 of the present embodiment is formed in a rectangular shape, for example, in which the length in the X-axis direction is longer than the length in the Y-axis direction when viewed from the +Z direction. Of course, the shape of the pressure chamber 312 when viewed from the +Z direction is not particularly limited, and can be a parallelogram shape, a polygonal shape, a circular shape, an elliptical shape, or the like. Further, the elliptical shape referred to here means a shape in which the two end portions in the long side direction are formed in a semicircular shape on the basis of a rectangular shape, and includes a rounded rectangular shape, an elliptical shape, an oval shape, and the like.

[0146] As shown in FIG. 3, the pressure chamber 312 is formed in a rectangular shape in which the length in the X-axis direction is longer than the length in the Y-axis direction when viewed from the +Z direction. Figure 13 , Figure 16 The pressure chamber substrate 310, the communication plate 315, the nozzle plate 320, and the deformable substrate 345 are stacked in this order from the -Z axis direction side.

[0147] The communication plate 315 is provided with a nozzle communication passage 316 that communicates the pressure chamber 312 with the nozzle 321. Further, the communication plate 315 is provided with a first manifold portion 317 and a second manifold portion 318 that constitute a part of the manifold 400 that is a common liquid chamber that communicates with a plurality of pressure chambers 312. The first manifold portion 317 is provided so as to penetrate the communication plate 315 in the Z-axis direction. Further, the second manifold portion 318 is not provided so as to penetrate the communication plate 315 in the Z-axis direction, but is provided so as to be open on the surface on the +Z-axis direction side.

[0148] Further, the communication plate 315 is provided with a supply communication passage 319 that communicates with one end portion in the X-axis direction of the pressure chamber 312, in a manner independent for each of the pressure chambers 312. The supply communication passage 319 communicates the second manifold portion 318 with each of the pressure chambers 312, and thereby supplies ink in the manifold 400 to each of the pressure chambers 312.

[0149] As the communication plate 315, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, a metal substrate, or the like can be used. As the metal substrate, for example, a stainless steel substrate or the like can be given. Further, the communication plate 315 preferably uses a material having a thermal expansion coefficient substantially the same as that of the pressure chamber substrate 310. Thereby, it is possible to reduce the possibility that warping occurs in the pressure chamber substrate 310 and the communication plate 315 due to a difference in thermal expansion coefficient when the temperature of the pressure chamber substrate 310 and the communication plate 315 changes.

[0150] The nozzle plate 320 is provided on the surface on the +Z-axis direction side of the communication plate 315 opposite the pressure chamber substrate 310. The nozzle plate 320 is formed with nozzles 321 that communicate with each of the pressure chambers 312 via the nozzle communication passages 316.

[0151] In the present embodiment, the plurality of nozzles 321 are arranged in a row along the Y-axis direction. Further, on the nozzle plate 320, the nozzle rows in which the plurality of nozzles 321 are arranged are provided in two rows in the X-axis direction. The two rows of nozzle rows are provided separately corresponding to the first pressure chamber row and the second pressure chamber row. The plurality of nozzles 321 of each row are arranged so that the positions in the X-axis direction are the same. Further, the arrangement of the nozzles 321 is not particularly limited. For example, the nozzles 321 arranged in a row in the Y-axis direction can be arranged at positions staggered in the X-axis direction at every other position.

[0152] As the material of the nozzle plate 320, there is no particular limitation, and for example, a silicon substrate, a glass substrate, an SOI substrate, various ceramic substrates, a metal substrate can be used. As the metal substrate, for example, a stainless steel substrate or the like can be given. Further, as the material of the nozzle plate 320, an organic substance such as a polyimide resin or the like can also be used. However, the nozzle plate 320 preferably uses a material having substantially the same coefficient of thermal expansion as the communication plate 315. Thereby, it is possible to reduce the possibility of warping on the nozzle plate 320 and the communication plate 315 due to the difference in the coefficient of thermal expansion when the temperature of the nozzle plate 320 and the communication plate 315 changes.

[0153] The deformable substrate 345 is provided on the side of the communication plate 315 opposite to the pressure chamber substrate 310, that is, the +Z-axis direction side, together with the nozzle plate 320. The deformable substrate 345 is provided around the nozzle plate 320 and seals the openings of the first manifold portion 317 and the second manifold portion 318 provided in the communication plate 315. The deformable substrate 345 includes a sealing film 346 composed of a thin film having flexibility and a fixed substrate 347 composed of a hard material such as metal. The region of the fixed substrate 347 opposite to the manifold 400 becomes an opening portion 348 completely removed in the thickness direction. Therefore, one side of the manifold 400 becomes a deformable portion 349 sealed only by the sealing film 346 having flexibility.

[0154] On the other hand, on the side of the pressure chamber substrate 310 opposite to the nozzle plate 320 or the like, that is, the -Z-axis direction side, a vibration plate 350 and a piezoelectric element 60 that deforms the vibration plate 350 to cause a pressure change in the ink in the pressure chamber 312 are laminated, as will be described later in detail. In other words, the vibration plate 350 is provided in the +Z-axis direction with respect to the piezoelectric element 60, and the pressure chamber substrate 310 is provided in the +Z-axis direction with respect to the vibration plate 350. Further, Figure 15 is a view for explaining the overall configuration of the ejection module 22, and the configuration of the piezoelectric element 60 is simply shown.

[0155] On the side of the face of the pressure chamber substrate 310 in the -Z-axis direction, a protection substrate 330 having substantially the same size as the pressure chamber substrate 310 is joined by an adhesive or the like. The protection substrate 330 has a holding portion 331 that is a space for protecting the piezoelectric elements 60. The holding portion 331 is provided independently for each column of the piezoelectric elements 60 arranged in the Y-axis direction, and two are arranged in the X-axis direction. In addition, on the protection substrate 330, a through-hole 332 that penetrates in the Z-axis direction is provided between the two holding portions 331 arranged in the X-axis direction.

[0156] In addition, a housing member 340 that divides a manifold 400 that communicates with the plurality of pressure chambers 312 together with the pressure chamber substrate 310 is fixed to the protection substrate 330. The housing member 340 has substantially the same shape as the above-mentioned communication plate 315 when viewed from the -Z-axis direction, is joined to the protection substrate 330, and is also joined to the above-mentioned communication plate 315.

[0157] Such a housing member 340 has a housing portion 341 that is a space capable of housing the depth of the pressure chamber substrate 310 and the protection substrate 330 on the side of the protection substrate 330. The housing portion 341 has a larger opening area than the face of the protection substrate 330 that is joined to the pressure chamber substrate 310. Furthermore, in a state in which the pressure chamber substrate 310 and the protection substrate 330 are housed in the housing portion 341, the opening face of the housing portion 341 on the nozzle plate 320 side is sealed by the communication plate 315.

[0158] In addition, on the housing member 340, a third manifold portion 342 is divided and formed on both outer sides of the housing portion 341 in the X-axis direction. Furthermore, the manifold 400 is constituted by the first manifold portion 317 and the second manifold portion 318 provided to the communication plate 315 and the third manifold portion 342. The manifold 400 is continuously provided in the entire Y-axis direction, and the supply communication passages 319 that communicate each pressure chamber 312 with the manifold 400 are arranged in the Y-axis direction.

[0159] In addition, a supply port 344 that communicates with the manifold 400 and is used to supply ink to each manifold 400 is provided on the housing member 340. Furthermore, a connection port 343 that communicates with the through-hole 332 of the protection substrate 330 and through which a wiring substrate 420 is inserted is provided on the housing member 340.

[0160] In this ejection module 22 of this embodiment, ink stored in the ink container 2 is taken in through the supply port 344, and after the ink fills the interior from the manifold 400 to the nozzle 321, a drive signal VOUT based on the drive signal COM is supplied from the integrated circuit 421, which includes the drive signal selection circuit 200, to each piezoelectric element 60 corresponding to the pressure chamber 312. As a result, the vibrating plate 350 and the piezoelectric element 60 flex and deform together, the pressure in each pressure chamber 312 increases, and ink is ejected from each nozzle 321. Moreover, the printhead 20 is configured by having multiple ejection modules 22 described above.

[0161] Next, the configuration, including the aforementioned vibrating plate 350 and piezoelectric element 60, which is stacked on the -Z-axis side of the pressure chamber substrate 310, will be described in detail. As a configuration stacked on the -Z-axis side of the pressure chamber substrate 310, in addition to the vibrating plate 350 and piezoelectric element 60, the ejection module 22 also includes an independent lead electrode 391, a common lead electrode 392, a measurement lead electrode 393, and a resistance wiring 401.

[0162] like Figure 15 to Figure 17 As shown, the vibrating plate 350 is composed of an elastic membrane 351 and an insulating membrane 352. The elastic membrane 351 is disposed on the pressure chamber substrate 310 side and is made of silicon oxide, while the insulating membrane 352 is disposed on the elastic membrane 351 and is made of zirconium oxide. The liquid flow channels of the pressure chamber 312, etc., are formed by anisotropic etching of the surface from the +Z axis direction side of the pressure chamber substrate 310, and the surface of the liquid flow channels of the pressure chamber 312, etc., in the -Z axis direction direction is composed of the elastic membrane 351.

[0163] Furthermore, the composition of the vibrating plate 350 is not particularly limited. For example, the vibrating plate 350 may be composed of either an elastic membrane 351 or an insulating membrane 352, or it may include other membranes besides the elastic membrane 351 and the insulating membrane 352. Examples of other membrane materials include silicon and silicon nitride.

[0164] The piezoelectric element 60 is an example of a piezoelectric actuator that causes pressure changes in the ink within the pressure chamber 312. This piezoelectric element 60 has a first electrode 360, a piezoelectric body 370, and a second electrode 380 stacked sequentially from the vibrating plate 350 side (+Z-axis direction) towards the -Z-axis direction. In other words, the piezoelectric element 60 includes a first electrode 360, a second electrode 380, and a piezoelectric body 370, with the piezoelectric body 370 disposed between the first electrode 360 ​​and the second electrode 380 in the Z-axis direction where the first electrode 360, the second electrode 380, and the piezoelectric body 370 are stacked.

[0165] The first electrode 360 and the second electrode 380 are electrically connected to the wiring substrate 420, and supply the piezoelectric body 370 with a drive signal VOUT supplied from a drive signal selection circuit 200 included in an integrated circuit 421 mounted to the wiring substrate 420, and a reference voltage signal VBS transmitted in the wiring substrate 420. The drive signal VOUT that differs depending on the amount of ink to be ejected is supplied to the first electrode 360, and the reference voltage signal VBS that is constant regardless of the amount of ink to be ejected is supplied to the second electrode 380. Thus, a potential difference is generated between the first electrode 360 and the second electrode 380, thereby deforming the piezoelectric body 370. That is, the vibration plate 350 is deformed or vibrated by driving the piezoelectric element 60, thereby changing the volume of the pressure chamber 312, and thus applying pressure to the ink accommodated in the pressure chamber 312. As a result, the ink is ejected from the nozzle 321 via the nozzle communication passage 316. In this case, the amount of change in the volume of the pressure chamber 312 becomes the amount of ink to be ejected.

[0166] A portion of the piezoelectric body 370 in which a piezoelectric strain is generated when a voltage is applied between the first electrode 360 and the second electrode 380 in the piezoelectric element 60 is referred to as an active portion 410. In contrast, a portion of the piezoelectric body 370 in which a piezoelectric strain is not generated is referred to as an inactive portion 415. That is, the portion of the piezoelectric element 60 in which the piezoelectric body 370 is sandwiched by the first electrode 360 and the second electrode 380 is the active portion 410, and the portion of the piezoelectric body 370 that is not sandwiched by the first electrode 360 and the second electrode 380 is the inactive portion 415. In addition, a portion that is displaced in the Z-axis direction when the piezoelectric element 60 is driven is referred to as a flexible portion, and a portion that is not displaced in the Z-axis direction is referred to as a non-flexible portion. That is, the portion of the piezoelectric element 60 that opposes the pressure chamber 312 in the Z-axis direction becomes the flexible portion, and the portion outside the pressure chamber 312 becomes the non-flexible portion. Furthermore, the active portion 410 is also referred to as an active portion, and the inactive portion 415 is also referred to as an inactive portion.

[0167] Generally, one electrode of the active portion 410 is configured as an independent electrode that is independent for each active portion 410, and the other electrode is configured as a common electrode that is common to a plurality of active portions 410. In the present embodiment, the first electrode 360 is configured as an independent electrode, and the second electrode 380 is configured as a common electrode.

[0168] Specifically, the first electrode 360 is disposed on the +Z-axis direction side of the piezoelectric body 370 in the Z-axis direction, and is divided for each pressure chamber 312, thereby being configured as an independent electrode that is independent for each active portion 410. That is, the first electrode 360 is independently disposed with respect to a plurality of pressure chambers 312. The first electrode 360 is formed in a width narrower than the width of the pressure chamber 312 in the Y-axis direction. That is, in the Y-axis direction, the end portion of the first electrode 360 is located inside the region opposing the pressure chamber 312.

[0169] In addition, the +X-direction end portion 360a and the -X-direction end portion 360b of the first electrode 360 are respectively arranged outside the pressure chamber 312. For example, in the first pressure chamber row, as shown in FIG. 3, the end portion 360a of the first electrode 360 is arranged at a position further to the +X-axis direction side than the +X-axis direction end portion 312a of the pressure chamber 312. The end portion 360b of the first electrode 360 is arranged at a position further to the -X-axis direction side than the -X-axis direction end portion 312b of the pressure chamber 312. Figure 16

[0170] The material of the first electrode 360 is not particularly limited, and for example, a conductive material such as a metal such as platinum (Pt), iridium (Ir), gold (Au), titanium (Ti), an electrically conductive metal oxide such as indium tin oxide (ITO), or the like can be used. Alternatively, a plurality of materials such as platinum (Pt), iridium (Ir), gold (Au), titanium (Ti), or the like can be stacked to be formed. In the present embodiment, platinum (Pt) is used as the first electrode 360.

[0171] As shown in FIG. 3, the piezoelectric body 370 is continuously provided in the entire Y-axis direction in a manner that the length in the X-axis direction is set to a predetermined length. That is, the piezoelectric body 370 is continuously provided in the direction in which the pressure chambers 312 are arranged, with a predetermined thickness. The thickness of the piezoelectric body 370 is not particularly limited, and is formed to a thickness of about 1000 nm to 4000 nm. Figure 14

[0172] In addition, as shown in FIG. 3, the length of the piezoelectric body 370 in the X-axis direction is longer than the length of the pressure chamber 312 in the long side direction, that is, the length in the X-axis direction. Therefore, on both sides of the pressure chamber 312 in the X-axis direction, the piezoelectric body 370 extends to the outside of the pressure chamber 312. In this way, by extending the piezoelectric body 370 to the outside of the pressure chamber 312 in the X-axis direction, the strength of the vibration plate 350 is improved. Therefore, it is possible to reduce the possibility of cracks or the like occurring in the vibration plate 350 or the piezoelectric element 60 when the active portion 410 is driven to displace the piezoelectric element 60. Figure 16 In addition, for example, in the first pressure chamber row, as shown in FIG. 3, the +X-direction end portion 370a of the piezoelectric body 370 is positioned further to the +X-axis direction side than the end portion 360a of the first electrode 360, which is outside. That is, the end portion 360a of the first electrode 360 is covered by the piezoelectric body 370. On the other hand, the -X-direction end portion 370b of the piezoelectric body 370 is positioned further to the +X-axis direction side than the end portion 360b of the first electrode 360, which is inside, and the end portion 360b of the first electrode 360 is not covered by the piezoelectric body 370.

[0173] Figure 16 Further, as shown in FIG. 3, the piezoelectric body 370 is continuously provided in the entire Y-axis direction in a manner that the length in the X-axis direction is set to a predetermined length. That is, the piezoelectric body 370 is continuously provided in the direction in which the pressure chambers 312 are arranged, with a predetermined thickness. The thickness of the piezoelectric body 370 is not particularly limited, and is formed to a thickness of about 1000 nm to 4000 nm.

[0174] Further, as shown in FIG. 3, the piezoelectric body 370 is continuously provided in the entire Y-axis direction in a manner that the length in the X-axis direction is set to a predetermined length. That is, the piezoelectric body 370 is continuously provided in the direction in which the pressure chambers 312 are arranged, with a predetermined thickness. The thickness of the piezoelectric body 370 is not particularly limited, and is formed to a thickness of about 1000 nm to 4000 nm. Figure 14 Figure 17 ​​​​As shown, a groove portion 371, which is a portion having a smaller thickness than other regions, is formed in the piezoelectric body 370 corresponding to each of the partition walls 311. The groove portion 371 of the present embodiment is formed by completely removing the piezoelectric body 370 in the Z-axis direction. That is, the piezoelectric body 370 having a portion with a smaller thickness than other regions also includes a case where the piezoelectric body 370 is completely removed in the Z-axis direction. Of course, the piezoelectric body 370 can be formed to have a smaller thickness than other portions also at the bottom surface of the groove portion 371.

[0175] In addition, the length in the Y-axis direction of the groove portion 371, that is, the width of the groove portion 371 is the same as or wider than the width of the partition wall 311. In the present embodiment, the width of the groove portion 371 is wider than the width of the partition wall 311.

[0176] Such a groove portion 371 is formed to have a rectangular shape when viewed from the -Z-axis direction side. Of course, the shape of the groove portion 371 when viewed from the -Z-axis direction side is not limited to a rectangular shape, and can be a polygonal shape of five sides or more, or a circular shape or an elliptical shape, and the like.

[0177] By providing the groove portion 371 in the piezoelectric body 370, the rigidity of the portion of the vibrating plate 350 that opposes the end portion of the pressure chamber 312 in the Y-axis direction, that is, the arm portion of the vibrating plate 350 is suppressed, and thus the piezoelectric element 60 can be caused to displace more favorably.

[0178] As the piezoelectric body 370, a crystal film of a perovskite structure formed on the first electrode 360, which is a strong dielectric ceramic material exhibiting an electromechanical conversion effect, that is, a so-called perovskite crystal can be given. As the material of the piezoelectric body 370, for example, a strong dielectric piezoelectric material such as lead zirconate titanate (PZT) or a material to which a metal oxide such as niobium oxide, nickel oxide, or magnesium oxide is added can be used. Specifically, lead titanate (PbTiO3), lead zirconate titanate (Pb(Zr,Ti)O3), lead zirconate (PbZrO3), lead lanthanum titanate ((Pb,La)TiO3), lead lanthanum zirconate titanate ((Pb,La)(Zr,Ti)O3), or lead zirconate titanate magnesium niobate (Pb(Zr,Ti)(Mg,Nb)O3), and the like can be used. In the present embodiment, lead zirconate titanate (PZT) is used as the piezoelectric body 370.

[0179] Furthermore, the material used for the piezoelectric element 370 is not limited to lead-based piezoelectric materials containing lead; lead-free, non-lead-based piezoelectric materials can also be used. Examples of non-lead-based piezoelectric materials include bismuth ferrite ((BiFeO3), abbreviated as "BFO"), barium titanate ((BaTiO3), abbreviated as "BT"), potassium sodium niobate ((K,Na)(NbO3), abbreviated as "KNN"), lithium sodium potassium niobate ((K,Na,Li)(NbO3)), lithium sodium potassium niobate ((K,Na,Li)(Nb,Ta)O3), potassium bismuth potassium titanate ((Bi1 / 2K1 / 2)TiO3, abbreviated as "BKT"), sodium bismuth titanate ((Bi1 / 2Na1 / 2)TiO3, abbreviated as "BNT"), and bismuth manganate (B iMnO3 (abbreviated as "BM"), composite oxides with a perovskite structure containing bismuth, potassium, titanium and iron (x[(BixK1-x)TiO3]-(1-x)[BiFeO3], abbreviated as "BKT-BF"), composite oxides with a perovskite structure containing bismuth, iron, barium and titanium ((1-x)[BiFeO3]-x[BaTiO3], abbreviated as "BFO-BT"), or substances formed by adding metals such as manganese, cobalt, chromium, etc. ((1-x)[Bi(Fe1-yMy)O3]-x[BaTiO3] (M is Mn, CO or Cr)), etc.

[0180] like Figure 14 , Figure 16 as well as Figure 17 As shown, the second electrode 380 is disposed on the side opposite to the first electrode 360, i.e., the -Z-axis side, and constitutes a common electrode shared by multiple active parts 410. That is, the second electrode 380 is provided as a common electrode for multiple pressure chambers 312. The second electrode 380 is continuously disposed in the entire Y-axis direction with a predetermined length in the X-axis direction. The second electrode 380 is also disposed on the inner surface of the groove 371, i.e., on the side surface of the groove 371 of the piezoelectric body 370, and on the insulating film 352 that serves as the bottom surface of the groove 371. Furthermore, regarding the groove 371, the second electrode 380 may be disposed only on a portion of the inner surface of the groove 371, or it may not cover the entire inner surface of the groove 371.

[0181] Additionally, for example, in the first pressure chamber row, such as Figure 16As shown, the end portion 380a of the second electrode 380 in the +X direction is arranged on the +X-axis direction side further outward than the end portion 360a of the first electrode 360 covered by the piezoelectric body 370. That is, the end portion 380a of the second electrode 380 is located on the +X-axis direction side further outward than the end portion 312a of the pressure chamber 312 and on the +X-axis direction side further outward than the end portion 360a of the first electrode 360. In the present embodiment, the end portion 380a of the second electrode 380 substantially coincides with the end portion 370a of the piezoelectric body 370 in the X-axis direction. Therefore, the end portion of the active portion 410 in the +X-axis direction, that is, the boundary between the active portion 410 and the inactive portion 415 is defined by the end portion 360a of the first electrode 360.

[0182] On the other hand, the end portion 380b of the second electrode 380 in the -X-axis direction is arranged on the -X-axis direction side further outward than the end portion 312b of the pressure chamber 312 and on the +X-axis direction side further inward than the end portion 370b of the piezoelectric body 370. As described above, the end portion 370b of the piezoelectric body 370 is located on the +X-axis direction side further inward than the end portion 360b of the first electrode 360. Therefore, the end portion 380b of the second electrode 380 is located on the piezoelectric body 370 on the +X-axis direction side further than the end portion 360b of the first electrode 360. Therefore, on the -X-axis direction side of the end portion 380b of the second electrode 380, there is a portion where the surface of the piezoelectric body 370 is exposed.

[0183] Thus, since the end portion 380b of the second electrode 380 is arranged on the +X-axis direction side further than the end portion 370b of the piezoelectric body 370 and the end portion 360b of the first electrode 360, the end portion of the active portion 410 in the -X-axis direction, that is, the boundary between the active portion 410 and the inactive portion 415 is defined by the end portion 380b of the second electrode 380.

[0184] The material of the second electrode 380 is not particularly limited and, like the first electrode 360, a conductive material such as a metal such as platinum (Pt), iridium (Ir), gold (Au), titanium (Ti), a conductive metal oxide such as indium tin oxide (ITO), or the like is used. Alternatively, a plurality of materials such as platinum (Pt), iridium (Ir), gold (Au), titanium (Ti), and the like can be stacked to form. In the present embodiment, iridium (Ir) is used as the second electrode 380.

[0185] In addition, a wiring portion 385 is provided on the outer side of the end portion 380b of the second electrode 380, that is, on the further -X-axis direction side of the end portion 380b of the second electrode 380, the wiring portion 385 being the same layer as the second electrode 380 but being electrically discontinuous from the second electrode 380. In addition, the wiring portion 385 is formed on the piezoelectric body 370 to the first electrode 360 provided extending further in the -X-axis direction than the piezoelectric body 370 in a state of being separated by a gap without contacting the end portion 380b of the second electrode 380. The wiring portion 385 is provided independently for each active portion 410. That is, the wiring portion 385 is provided with a plurality of portions arranged at a prescribed interval along the Y-axis direction. Furthermore, the wiring portion 385 can also be formed by a different layer from the second electrode 380, but is preferably formed by the same layer as the second electrode 380. Thereby, the manufacturing process of the wiring portion 385 can be simplified to achieve a reduction in cost.

[0186] In addition, on the first electrode 360 and the second electrode 380 constituting the piezoelectric element 60, the first electrode 360 is electrically connected to the independent lead electrode 391, and the second electrode 380 is electrically connected to the common lead electrode 392 which is a common electrode for driving. The end portion of the independent lead electrode 391 and the common lead electrode 392 on the opposite side to the end portion connected to the piezoelectric element 60 is electrically connected to a wiring substrate 420 having flexibility. On the wiring substrate 420, a plurality of wirings for connection to the control mechanism 10, the temperature information output circuit 26, and a plurality of circuits not shown are formed. In the present embodiment, the wiring substrate 420 is constituted by, for example, an FPC (Flexible Printed Circuit). Furthermore, instead of the FPC, any substrate having flexibility such as an FFC (Flexible Flat Cable) or the like can be used.

[0187] In the present embodiment, the independent lead electrode 391 and the common lead electrode 392 are provided extending in a manner exposed within the through-hole 332 formed in the protective substrate 330, and are electrically connected to the wiring substrate 420 within the through-hole 332. In addition, an integrated circuit 421 is mounted on the wiring substrate 420, the integrated circuit 421 mounting a drive signal selection circuit 200 which outputs a drive signal VOUT for driving the piezoelectric element 60.

[0188] In the present embodiment, the independent lead electrode 391 and the common lead electrode 392 are constituted by the same layer, but are formed to be electrically discontinuous. Thereby, compared to when the independent lead electrode 391 and the common lead electrode 392 are formed independently, the manufacturing process can be simplified to reduce the cost. Of course, the independent lead electrode 391 and the common lead electrode 392 can also be formed by different layers.

[0189] The material of the independent lead electrode 391 and the common lead electrode 392 is not particularly limited as long as it is a material having conductivity, and, for example, gold (Au), copper (Cu), titanium (Ti), tungsten (W), nickel (Ni), chromium (Cr), platinum (Pt), aluminum (Al), or the like can be used. In the present embodiment, gold (Au) is used as the independent lead electrode 391 and the common lead electrode 392. In addition, the independent lead electrode 391 and the common lead electrode 392 can have an adhesion layer that improves adhesion to the first electrode 360 and the second electrode 380 or the diaphragm 350.

[0190] The independent lead electrode 391 is provided for each active portion 410, that is, for each first electrode 360. As shown in FIG. 6, for example, in the first pressure chamber row, the independent lead electrode 391 is connected to the vicinity of the end portion 360b of the first electrode 360 provided outside the piezoelectric body 370 via the wiring portion 385 and is actually drawn out on the diaphragm 350 in the -X axis direction on the pressure chamber substrate 310. Figure 16

[0191] Figure 14 On the other hand, as shown in FIG. 7, for example, in the first pressure chamber row, the common lead electrode 392 is drawn out on the diaphragm 350 in the -X direction from the second electrode 380 that constitutes the common electrode on the piezoelectric body 370 at both ends in the Y axis direction. In addition, the common lead electrode 392 has an extension portion 392a and an extension portion 392b. As shown in FIG. 8, for example, in the first pressure chamber row, the extension portion 392a is provided so as to extend in the Y axis direction in a region corresponding to the end portion 312a of the pressure chamber 312, and the extension portion 392b is provided so as to extend in the Y axis direction in a region corresponding to the end portion 312b of the pressure chamber 312. These extension portions 392a and 392b are provided continuously in the Y axis direction with respect to the plurality of active portions 410. Figure 14 Figure 16

[0192] In addition, the extension portions 392a and 392b are provided so as to extend in the X axis direction from the inside of the pressure chamber 312 to the outside of the pressure chamber 312. In the present embodiment, the active portion 410 of the piezoelectric element 60 is provided so as to extend to the outside of the pressure chamber 312 at both end portions in the X axis direction of the pressure chamber 312, and the extension portions 392a and 392b are provided so as to extend to the outside of the pressure chamber 312 on the active portion 410.

[0193] Figure 16 ​​​​​As shown, a resistance wiring 401 is provided on the surface of the vibrating plate 350 in the -Z axis direction. The resistance wiring 401 constitutes at least a part of the temperature detection circuit 24 for detecting the temperature of the pressure chamber 312. The temperature detection circuit 24 of this embodiment utilizes the characteristic that the resistance value of a metal or semiconductor changes with temperature. The material of the resistance wiring 401 is not particularly limited as long as the resistance value is temperature-dependent, such as gold (Au), platinum (Pt), iridium (Ir), aluminum (Al), copper (Cu), titanium (Ti), tungsten (W), nickel (Ni), chromium (Cr), etc. Among these, from the viewpoint of large resistance value change due to temperature and high stability and accuracy, platinum (Pt) can be appropriately used as the material of the resistance wiring 401. In this embodiment, the resistance wiring 401 is formed on the surface of the vibrating plate 350 in the -Z axis direction in a manner that is co-layered with the first electrode 360 ​​but electrically discontinuous with the first electrode 360. Therefore, the material of the resistance wiring 401 is platinum (Pt), the same as that of the first electrode 360. Therefore, compared to forming the resistor wiring 401 and the first electrode 360 ​​separately, the manufacturing process can be simplified and costs reduced. Of course, the resistor wiring 401 can also be formed from a different layer than the first electrode 360.

[0194] like Figure 14 As shown, the resistance wiring 401 is continuous. One end of the resistance wiring 401 on the +X-axis side in the X-axis direction is connected to the measuring lead electrode 393a, and the other end of the resistance wiring 401 on the -X-axis side in the X-axis direction is connected to the measuring lead electrode 393b. Furthermore, the measuring lead electrodes 393a and 393b are electrically connected to the wiring substrate 420. Thus, the resistance wiring 401 is electrically connected to the temperature information output circuit 26, which can measure the resistance value of the resistance wiring 401. In this embodiment, the resistance wiring 401 is covered by a piezoelectric element 370 and is located between the vibrating plate 350 and the piezoelectric element 370 in the Z-axis direction.

[0195] The resistance wiring 401 has a first pressure chamber column side meandering pattern on the +X-axis direction side in the X-axis direction and a second pressure chamber column side meandering pattern on the -X-axis direction side in the X-axis direction. The first pressure chamber column side meandering pattern meanders in the Y-axis direction at a position overlapping the supply communication passage 319 that communicates with each pressure chamber 312 constituting the first pressure chamber column, as viewed from the -Z-axis direction. The second pressure chamber column side meandering pattern meanders in the Y-axis direction at a position overlapping the supply communication passage 319 that communicates with each pressure chamber 312 constituting the second pressure chamber column, as viewed from the -Z-axis direction. That is, the resistance wiring 401 has the first pressure chamber column side meandering pattern corresponding to the first pressure chamber column formed of the plurality of pressure chambers 312 and the second pressure chamber column side meandering pattern corresponding to the second pressure chamber column formed of the plurality of pressure chambers 312. In addition, as shown in Figs. 6 and 7, the distance of the -Z-axis direction side end of the pressure chamber 312 from the resistance wiring 401 in the Z-axis direction is shorter than the size of the pressure chamber 312 in the Z-axis direction. In addition, for example, in the first pressure chamber column, the distance of the +X direction side end 312a of the pressure chamber 312 from the resistance wiring 401 in the X-axis direction is shorter than the size of the pressure chamber 312 in the X-axis direction. Therefore, the resistance value of the resistance wiring 401 easily changes in correspondence with the temperature change of the pressure chamber 312. Figure 15 、 Figure 16

[0196] In the present embodiment, the measurement lead electrode 393 including the measurement lead electrodes 393a and 393b is formed of the same layer as the independent lead electrode 391 and the common lead electrode 392, but is formed to be electrically discontinuous. Thereby, compared to when the measurement lead electrode 393 is formed independently from the independent lead electrode 391 and the common lead electrode 392, the manufacturing process can be simplified to reduce costs. Of course, the measurement lead electrode 393 can also be formed in a different layer from the independent lead electrode 391 and the common lead electrode 392.

[0197] The material of the measurement lead electrode 393 is not particularly limited as long as it is a material having electrical conductivity, and for example, gold (Au), copper (Cu), titanium (Ti), tungsten (W), nickel (Ni), chromium (Cr), platinum (Pt), aluminum (Al), or the like can be used. In the present embodiment, gold (Au) is used as the measurement lead electrode 393. Therefore, the material of the measurement lead electrode 393 is the same material as the independent lead electrode 391 and the common lead electrode 392. In addition, the measurement lead electrode 393 can also have an adhesion layer that improves adhesion to the resistance wiring 401 or the vibrating plate 350.

[0198] ​In the present embodiment, the measurement lead electrode 393 is provided so as to extend in a manner exposed in the through-hole 332 formed in the protective substrate 330, and is electrically connected to the wiring substrate 420 in the through-hole 332. Thus, the temperature information output circuit 26 can acquire the resistance value of the resistance wiring 401 via the wiring substrate 420. Also, the temperature information output circuit 26 outputs the acquired resistance value of the resistance wiring 401 as the temperature information signal TI in accordance with a temperature acquisition request signal TD from the control circuit 100. Alternatively, the temperature information output circuit 26 can also store in advance a correspondence relationship between the resistance value of the resistance wiring 401 and the temperature. Also, the temperature information output circuit 26 can also output the temperature corresponding to the resistance value of the resistance wiring 401 as the temperature information signal TI in accordance with the temperature acquisition request signal TD from the control circuit 100.

[0199] For example, when the temperature detection circuit 24 is provided outside the ejection module 22, the difference between the temperature detected by the temperature detection circuit 24 and the temperature in the pressure chamber 312, and the difference between the temperature in the ejection module 22 and the temperature in the pressure chamber 312 can be larger. In this case, the correction control by the control circuit 100 to correct the control signals Ctrl-H, Ctrl-C, Ctrl-T in accordance with the temperature information signal TI can be reduced, and it can not be possible to perform optimal ejection control of the ejection module 22 that is appropriate for the temperature of the ink in the pressure chamber 312. In the present embodiment, the resistance wiring 401 is provided so as to be laminated to the vibration plate 350 inside the ejection module 22. Thus, it is possible to reduce the difference between the temperature detected by the resistance wiring 401 as the temperature detection circuit 24 and the temperature in the pressure chamber 312, and to improve the detection accuracy of the temperature of the pressure chamber 312 detected by the temperature detection circuit 24. As a result, it is possible to perform ejection control of the ejection module 22 that is appropriate for the temperature of the ink in the pressure chamber 312 by the control circuit 100.

[0200] That is, the ejection module 22 of the print head 20 of the present embodiment includes: a piezoelectric element 60 that receives a drive signal VOUT based on a drive signal COM to be driven, and includes a first electrode 360, a second electrode 380, and a piezoelectric body 370, the piezoelectric body 370 being located between the first electrode 360 and the second electrode 380 in a Z-axis direction that is a stacking direction in which the first electrode 360, the second electrode 380, and the piezoelectric body 370 are stacked; a vibration plate 350 that is located on a +Z-axis direction side that is one side in the stacking direction, i.e., the Z-axis direction, with respect to the piezoelectric element 60, and deforms under the drive of the piezoelectric element 60; a pressure chamber substrate 310 that is located on the +Z-axis direction side that is one side in the stacking direction, i.e., the Z-axis direction, with respect to the vibration plate 350, and is provided with a plurality of pressure chambers 312 whose volumes change according to the deformation of the vibration plate 350; a drive signal selection circuit 200 that switches whether or not to supply the drive signal COM to the piezoelectric element 60; a wiring substrate 420 that is provided with an integrated circuit 421 including the drive signal selection circuit 200; and a resistance wiring 401 that is located on a -Z-axis direction side that is the other side in the stacking direction, i.e., the Z-axis direction, with respect to the vibration plate 350, and is electrically connected to the wiring substrate 420, and constitutes at least a part of a temperature detection circuit 24 that detects temperature information of the pressure chamber 312.

[0201] Thus, the difference between the temperature detected based on the resistance value of the resistance wiring 401 that is the temperature detection circuit 24 and the temperature in the pressure chamber 312 can be reduced, and the detection accuracy of the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 is improved. As a result, the ejection control of the ejection module 22 that is appropriate for the temperature of the ink in the pressure chamber 312 can be performed by the control circuit 100.

[0202] Further, by laminating at least a part of the resistance wiring 401 that is the temperature detection circuit 24 to the vibration plate 350, it is possible to further arrange the resistance wiring 401 that is the temperature detection circuit 24 in the vicinity of the pressure chamber 312, and the detection accuracy of the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 is further improved. As a result, the ejection control of the ejection module 22 that is more appropriate for the temperature of the ink in the pressure chamber 312 can be performed by the control circuit 100.

[0203] 6. Temperature detection operation

[0204] As described above, in the liquid ejection apparatus 1 of the present embodiment, since the resistance wiring 401 that detects the temperature of the ejection module 22 is provided on the vibration plate 350 inside the ejection module 22 provided in the print head 20, it is possible to arrange the resistance wiring 401 that is the temperature detection circuit 24 in the vicinity of the pressure chamber 312 that stores the ink.

[0205] Thus, the difference between the temperature detected based on the resistance value of the resistance wiring 401 and the temperature in the pressure chamber 312 can be reduced, the detection accuracy of the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 is improved, and as a result, the signal waveform of the drive signal COM can be corrected to an optimal signal waveform corresponding to the temperature of the pressure chamber 312, that is, the temperature of the ink stored in the pressure chamber 312, and as a result, the ejection accuracy of the ink can be improved.

[0206] On the other hand, since the resistance wiring 401 as the temperature detection circuit 24 is disposed in the vicinity of the pressure chamber 312 in which the ink is stored, the following problem occurs.

[0207] In recent years, from the viewpoint of improving the image quality formed on the medium P, several hundreds or more of the nozzles 321 are densely arranged in the ejection module 22. Therefore, in the ejection module 22, several hundreds or more of the piezoelectric elements 60 corresponding to the several hundreds or more of the nozzles 321 are densely arranged, and thus, the signal wiring that transmits the drive signal VOUT supplied to the corresponding piezoelectric elements 60 is densely arranged in the ejection module 22. In the case where the resistance wiring 401 is arranged on such a vibration plate 350, the resistance wiring 401 is arranged in the vicinity of the signal wiring that transmits the drive signal VOUT. Therefore, the possibility that the voltage value of the drive signal VOUT overlaps with the signal transmitted by the resistance wiring 401 is increased, and in the case where the voltage value of the drive signal VOUT overlaps with the signal transmitted by the resistance wiring 401, the detection accuracy of the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 including the resistance wiring 401 is decreased.

[0208] In particular, in such a drive circuit 50 shown in the present embodiment, since the drive circuit 50 modulates the base drive signal aO corresponding to the base drive signal dO and digitally amplifies it, the power consumption in the drive circuit 50 can be reduced. On the other hand, a high-frequency pulsating voltage is overlapped in the signal waveform of the drive signal COM output from the drive circuit 50 and the signal waveform of the drive signal VOUT based on the drive signal COM. Therefore, the possibility that the drive signal VOUT overlaps with the signal transmitted by the resistance wiring 401 is further increased, and even in the case where the signal waveform of the drive signal COM is corrected based on the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 including the resistance wiring 401, it can be difficult to perform the optimal correction of the signal waveform of the drive signal COM.

[0209] In view of such a problem, the liquid ejecting apparatus 1 of the present embodiment has the following characteristic configuration: the temperature detection circuit 24 detects the frequency of the amplification modulation signal AMs at the time of temperature detection information TH used by the control circuit 100 to correct the basic drive signal dO, and the frequency is higher than the frequency of the amplification modulation signal AMs at the time of temperature detection information TH not used by the control circuit 100 to correct the basic drive signal dO. The print head 20 has the following characteristic configuration: the frequency of the amplification modulation signal AMs at the time of temperature detection information TH detected by the temperature detection circuit 24 being output to the control circuit 100 is higher than the frequency of the amplification modulation signal AMs at the time of temperature detection information TH not being output to the control circuit 100.

[0210] As a result, the influence of the pulsating voltage on the temperature detection information TH input to the control circuit 100 is reduced, and the detection accuracy of the temperature detection information TH used by the control circuit 100 to correct the basic drive signal dO is improved. As a result, the correction accuracy of the signal waveform of the drive signal COM when the signal waveform of the drive signal COM is corrected using the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 including the resistance wiring 401 can be improved.

[0211] A specific operation example of the liquid ejecting apparatus 1 operating as described above will be described. Figure 18 is a diagram showing an example of the acquisition timing at which the temperature acquisition module 22 provided in the print head 20 acquires the temperature.

[0212] The liquid ejecting apparatus 1 is activated and starts to operate by being supplied with a power supply voltage. At this time, as an initial setting of the liquid ejecting apparatus 1, the control circuit 100 holds the temperature detection flag Ft indicating whether or not the temperature of the pressure chamber 312 is required to be detected by the temperature detection circuit 24 at an L level indicating that the temperature is not required to be detected. That is, the control circuit 100 sets the temperature detection flag Ft = "L" (step S10).

[0213] Then, when a print request with respect to the liquid ejecting apparatus 1 is generated by inputting an image information signal including image data and the like from an external device (step S20), the control circuit 100 outputs a control signal Ctrl-C for moving the carriage 21 along the scanning axis. As a result, the carriage 21 moves along the scanning axis (step S30).

[0214] The linear encoder 90 outputs a detection signal based on the scan position of the carriage 21 to the control circuit 100 by moving the carriage 21. The control circuit 100 determines whether the scan position of the carriage 21, that is, the scan position of the print head 20 is in the printing region based on the input detection signal (step S40). Here, the printing region refers to a region in which the print head 20 mounted on the carriage 21 ejects ink toward the medium P, and is a region defined based on the scan range of the carriage 21 or the width of the medium P conveyed in the direction of the scan axis. In addition, in the following description, a region other than the above-described printing region within the scan range of the carriage 21 is referred to as a non-printing region.

[0215] When the control circuit 100 determines that the scan position of the carriage 21 is in the printing region (YES in step S40), the liquid ejection device 1 executes a printing process (step S50). The printing process refers to a process of forming a desired image on the medium P by ejecting ink toward a desired position of the medium P by the print head 20, and includes, for example, a process in which the control circuit 100 outputs a head control signal DI corresponding to image data input from an external device to the print head 20, and the like.

[0216] In addition, during the execution of the printing process, the frequency measurement circuit 54 measures the frequency of the amplified modulation signal AMs of the drive circuit 50. Also, the frequency measurement circuit 54 outputs a frequency determination signal Fm that becomes an H level at the timing at which the frequency of the amplified modulation signal AMs becomes the maximum, and that becomes an H level and continues for a certain period at the instant at which the frequency of the amplified modulation signal AMs changes from rising to falling. The control circuit 100 calculates the voltage value of the drive signal COM at the instant at which the frequency determination signal Fm becomes an H level based on the base drive signal dO output at the instant at which the frequency determination signal Fm becomes an H level, and stores the calculated voltage value of the drive signal COM as the voltage Vbe. That is, the control circuit 100 acquires the voltage value of the drive signal COM at the time at which the frequency of the amplified modulation signal AMs is the maximum as the voltage Vbe (step S60).

[0217] Here, in the above-described embodiment, the step S50 and the step S60 are described as being executed in this order, but the voltage value of the drive signal COM at the time at which the frequency of the amplified modulation signal AMs is the maximum shown in the step S60 can be acquired during the execution of the printing process in the step S50. Figure 18

[0218] ​Further, after the acquisition of the voltage value of the drive signal COM at the maximum frequency of the print processing and the amplification modulation signal AMs is completed, the control circuit 100 performs a determination as to whether a temperature detection request to detect the temperature of the pressure chamber 312 by the temperature detection circuit 24 based on the usage condition of the liquid discharge apparatus 1 or a request from the user has been generated (step S70). When the control circuit 100 determines that the temperature detection request to detect the temperature of the pressure chamber 312 by the temperature detection circuit 24 has been generated (YES in step S70), the control circuit 100 holds the temperature detection flag Ft at the H level indicating that the temperature of the pressure chamber 312 needs to be detected by the temperature detection circuit 24. That is, the control circuit 100 sets the temperature detection flag Ft = "H" (step S80).

[0219] Further, when the control circuit 100 determines that the temperature detection request to detect the temperature of the pressure chamber 312 by the temperature detection circuit 24 has not been generated (NO in step S70), or after the control circuit 100 determines that the temperature detection request to detect the temperature of the pressure chamber 312 by the temperature detection circuit 24 has been generated and sets the temperature detection flag Ft = "H" (step S80), the control circuit 100 determines whether the print processing corresponding to the image data input from the external device has been completed (step S90).

[0220] Further, when the control circuit 100 determines that the print processing has not been completed (NO in step S90), the control circuit 100 again determines whether the scan position of the carriage 21, that is, the scan position of the print head 20 is in the printing region based on the input detection signal (step S40). On the other hand, when the control circuit 100 determines that the print processing has been completed (YES in step S90), the control circuit 100 stops the movement of the carriage 21 (step S170), and the liquid discharge apparatus 1 stops the operation.

[0221] When the control circuit 100 determines that the scan position of the carriage 21 is not in the printing region (NO in step S40), that is, the control circuit 100 determines that the scan position of the carriage 21 is in the printing-out region, the control circuit 100 determines whether the held temperature detection flag Ft is the L level indicating that the temperature of the pressure chamber 312 does not need to be detected by the temperature detection circuit 24 (step S100).

[0222] When the temperature detection flag Ft held by the control circuit 100 is the H level (NO in step S100), the control circuit 100 sets all of the ejection data [SIH, SIL] included in the ejection control signal SI of the head control signal DI to the ejection data [SIH, SIL] = [0, 0] and outputs (step S110). Thus, all of the selection circuits 230 included in the drive signal selection circuit 200 are controlled to be non-conductive.

[0223] Then, the control circuit 100 reads out the voltage Vbe obtained in step S60, and outputs a basic drive signal dO for outputting a drive signal COM whose voltage value is constant at the voltage Vbe. Thereby, the drive circuit 50 outputs, as the drive signal COM, a signal whose voltage value is constant at the voltage Vbe (step S120). Then, the control circuit 100 generates a temperature acquisition request signal TD for acquiring the temperature of the ejection module 22 that the print head 20 has, and outputs it to the temperature information output circuit 26. The temperature information output circuit 26 generates a temperature information signal TI corresponding to the temperature detection information TH that is information input from the temperature detection circuit 24 and corresponding to the temperature of the pressure chamber 312, in accordance with the input temperature acquisition request signal TD, and outputs it to the control circuit 100. Thereby, the control circuit 100 acquires the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 (step S130).

[0224] Specifically, the temperature information output circuit 26 holds and amplifies the temperature detection information TH that is input from the temperature detection circuit 24 at the timing when the temperature acquisition request signal TD is input, and that corresponds to the temperature of the pressure chamber 312. Also, a signal on which the temperature detection information TH is amplified is output as the temperature information signal TI. That is, the temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 is input to the control circuit 100 as the temperature information signal TI. At this time, all of the selection circuits 230 included in the drive signal selection circuit 200 are controlled to be non-conductive, and the drive circuit 50 outputs the drive signal COM whose constant voltage value is constant at the voltage Vbe, that is, the drive signal COM whose voltage value constant at the voltage Vbe at which the frequency of the amplified modulation signal AMs becomes the maximum. That is, during the period when all of the selection circuits 230 do not supply the drive signal COM to the plurality of piezoelectric elements 60, that is, during the period when the drive circuit 50 outputs the drive signal COM whose voltage value constant at the voltage Vbe at which the frequency of the amplified modulation signal AMs becomes the maximum, the control circuit 100 is input the temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24. In other words, during the period when all of the selection circuits 230 do not supply the drive signal COM to the plurality of piezoelectric elements 60, that is, during the period when the drive signal COM whose voltage value constant at the voltage Vbe at which the frequency of the amplified modulation signal AMs becomes the maximum is input, the print head 20 outputs the temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24.

[0225] At this time, the temperature information output circuit 26 can hold all the temperature detection information TH1 to THn output from the temperature detection circuits 24 possessed by the ejection modules 22-1 to 22-n at the timing when the temperature acquisition request signal TD is input, and output signals amplified with respect to the held temperature detection information TH1 to THn as the temperature information signal TI to the control circuit 100, or can hold the temperature detection information TH1 to THn specified by the temperature acquisition request signal TD from among the temperature detection information TH1 to THn output from the temperature detection circuits 24 possessed by the ejection modules 22-1 to 22-n at the timing when the temperature acquisition request signal TD is input, and output signals amplified with respect to the held temperature detection information TH1 to THn as the temperature information signal TI to the control circuit 100.

[0226] Further, the control circuit 100 corrects the control signals Ctrl-H, Ctrl-C, Ctrl-T and the basic drive signal dO in accordance with the temperature information signal TI obtained, which includes the temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24. That is, the control circuit 100 corrects the basic drive signal dO in accordance with the temperature of the pressure chamber 312 (step S140). In other words, during the period when the drive circuit 50 outputs the drive signal COM of the constant voltage value constant at the voltage Vbe, that is, when the frequency of the amplified modulation signal AMs is maximum, the control circuit 100 corrects the basic drive signal dO in accordance with the temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24.

[0227] Then, the control circuit 100 considers that the temperature acquisition of the pressure chamber 312 of the ejection module 22 has been completed, and holds the temperature detection flag Ft as the L level indicating that the temperature detection of the pressure chamber 312 by the temperature detection circuit 24 is not required. That is, the control circuit 100 sets the temperature detection flag Ft = "L" (step S150).

[0228] Further, when the scan position of the carriage is in the outside area of the printing and the temperature detection flag Ft held by the control circuit 100 is the L level (YES in step S100), or after the control circuit 100 completes the temperature acquisition of the pressure chamber 312 and sets the temperature detection flag Ft = "L" (step S150), the control circuit 100 outputs the control signal Ctrl-C for reversing the moving direction of the carriage 21 by causing the scan position of the carriage 21 to reach the prescribed area. Thus, the carriage 21 moves in the reversed moving direction along the scan axis. That is, the moving direction is reversed, and the carriage 21 moves along the scan axis (step S160).

[0229] After the direction of movement of the carriage is reversed, the control circuit 100 performs a determination as to whether a temperature detection request to detect the temperature of the pressure chamber 312 with the temperature detection circuit 24 based on the usage condition of the liquid discharge apparatus 1 or a request from the user has been made (step S70). When the control circuit 100 determines that the temperature detection request to detect the temperature of the pressure chamber 312 with the temperature detection circuit 24 has been made (YES in step S70), the control circuit 100 holds the temperature detection flag Ft at the H level indicating that the temperature of the pressure chamber 312 needs to be detected with the temperature detection circuit 24. That is, the control circuit 100 sets the temperature detection flag Ft = "H" (step S80).

[0230] Further, when the control circuit 100 determines that the temperature detection request to detect the temperature of the pressure chamber 312 with the temperature detection circuit 24 has not been made (NO in step S70), or after the control circuit 100 determines that the temperature detection request to detect the temperature of the pressure chamber 312 with the temperature detection circuit 24 has been made and sets the temperature detection flag Ft = "H" (step S80), the control circuit 100 determines whether the printing process corresponding to the image data input from the external device has been completed (step S90).

[0231] Further, when the control circuit 100 determines that the printing process has not been completed (NO in step S90), the control circuit 100 again determines whether the scan position of the carriage 21, that is, the scan position of the print head 20 is in the printing region based on the input detection signal (step S40). On the other hand, when the control circuit 100 determines that the printing process has been completed (YES in step S90), the control circuit 100 stops the movement of the carriage 21 (step S170), and the liquid discharge apparatus 1 stops operating.

[0232] Here, the control circuit 100 is an example of the basic drive signal output circuit, the configuration including the drive circuit 50 and the control circuit 100 is an example of the drive signal output circuit, and the drive signal COM is an example of the drive signal. In addition, in view of the fact that the trapezoidal waveforms Adp, Bdp, and Cdp included in the drive signal COM are supplied to the piezoelectric element 60, the trapezoidal waveforms Adp, Bdp, and Cdp included in the drive signal COM are also examples of the drive signal. In addition, the Z-axis direction is an example of the stacking direction, the +Z-axis direction side of the Z-axis direction as the stacking direction is an example of one side of the stacking direction, and the -Z-axis direction side of the Z-axis direction as the stacking direction is an example of the other side of the stacking direction. In addition, the selection circuit 230 is an example of the switching circuit. Further, the temperature detection circuit 24 is an example of the temperature detection unit, and the temperature detection information TH output from the temperature detection circuit 24 is an example of the temperature information.

[0233] 7. EFFECTS

[0234] As described above, in the liquid ejecting apparatus 1 of the present embodiment, by making the frequency of the amplification modulation signal AMs at the time when the temperature detection circuit 24 detects the temperature detection information TH used by the control circuit 100 to correct the basic drive signal dO higher than the frequency of the amplification modulation signal AMs at the time when the temperature detection circuit 24 detects the temperature detection information TH not used by the control circuit 100 to correct the basic drive signal dO, it is possible to reduce the amplitude of the pulsating voltage that overlaps with the drive signal COM at the time when the temperature detection information TH detected by the temperature detection circuit 24 is output to the control circuit 100. That is, the print head 20 makes the frequency of the amplification modulation signal AMs at the time when the temperature detection information TH detected by the temperature detection circuit 24 is output to the control circuit 100 higher than the frequency of the amplification modulation signal AMs at the time when the temperature detection information TH detected by the temperature detection circuit 24 is not output to the control circuit 100, thereby making the amplitude of the pulsating voltage that overlaps with the input drive signal COM smaller.

[0235] Thus, the possibility that the pulsating voltage that overlaps with the drive signal COM overlaps with the temperature detection information TH detected by the temperature detection circuit 24 is reduced, and the detection accuracy of the temperature detection information TH used by the control circuit 100 to correct the basic drive signal dO is improved. As a result, it is possible to further improve the correction accuracy of the signal waveform of the drive signal COM at the time when the signal waveform of the drive signal COM is corrected using the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 including the resistance wiring 401.

[0236] Further, the control circuit 100 corrects the basic drive signal dO according to the temperature detection information TH corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 at the time when the drive circuit 50 outputs the drive signal COM whose constant voltage value is constant at the voltage Vbe, that is, at the time when the frequency of the amplification modulation signal AMs is the largest, it is possible to further reduce the amplitude of the pulsating voltage that overlaps with the drive signal COM, the possibility that the pulsating voltage that overlaps with the drive signal COM overlaps with the temperature detection information TH detected by the temperature detection circuit 24 is further reduced, and the detection accuracy of the temperature detection information TH used by the control circuit 100 to correct the basic drive signal dO is further improved. As a result, it is possible to further improve the correction accuracy of the signal waveform of the drive signal COM at the time when the signal waveform of the drive signal COM is corrected using the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 including the resistance wiring 401.

[0237] 8. Modified example

[0238] In the liquid ejecting apparatus 1 of the present embodiment described above, the frequency measurement circuit 54 of the control mechanism 10 outputs the frequency determination signal Fm at the frequency at which the frequency of the amplified modulation signal AMs becomes the maximum timing output H level, and the control circuit 100 calculates the voltage value of the drive signal COM at the timing at which the H level input frequency determination signal Fm is input. Also, based on the control of the control circuit 100, the drive circuit 50 outputs the drive signal COM at a constant voltage value at which the frequency of the amplified modulation signal AMs becomes the maximum. Thus, when acquiring the temperature detection information TH used by the control circuit 100 to correct the basic drive signal dO, the amplitude of the pulsating voltage superimposed on the drive signal COM can be maximally reduced, and thus the possibility that the pulsating voltage superimposed on the drive signal COM overlaps the temperature detection information TH detected by the temperature detection circuit 24 is reduced, and the detection accuracy of the temperature detection information TH used by the control circuit 100 to correct the basic drive signal dO is improved.

[0239] On the other hand, from the viewpoint of improving the correction accuracy of the signal waveform of the drive signal COM when correcting the signal waveform of the drive signal COM using the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 including the resistance wiring 401, it is only necessary to reduce the pulsating voltage superimposed on the drive signal COM to at least a degree at which the possibility that the pulsating voltage superimposed on the drive signal COM overlaps the temperature detection information TH detected by the temperature detection circuit 24 is reduced. Thus, in a case where the pulsating voltage can be reduced to a degree at which the possibility that the pulsating voltage overlaps the temperature detection information TH detected by the temperature detection circuit 24 is reduced and the frequency is known, it is also possible that the frequency measurement circuit 54 outputs the frequency determination signal Fm corresponding to whether or not the frequency of the amplified modulation signal AMs is equal to or greater than a prescribed threshold value, and the control circuit 100 controls the voltage value of the drive signal COM in such a manner that the frequency of the amplified modulation signal AMs becomes equal to or greater than the prescribed threshold value.

[0240] By being configured in such a manner, it is possible to simplify the configuration of the frequency measurement circuit 54, and to miniaturize the control mechanism 10 and the liquid ejecting apparatus 1.

[0241] In addition, in view of the fact that the drive circuit 50 self-oscillates at a frequency determined by the delay of the feedback of the feedback circuits 570, 572 and the transfer function of the feedback, from the viewpoint of circuit efficiency, the waveform accuracy of the output signal, and the stability of the operation, the frequency of the self-oscillation is preferably maximized at a voltage value between the maximum voltage and the minimum voltage of the output signal, and more preferably maximized at a voltage value near the average voltage of the maximum voltage and the minimum voltage.

[0242] Therefore, the liquid ejecting apparatus 1 can also not have the frequency measuring circuit 54, and the acquisition control circuit 100 can be used to correct the voltage value of the drive signal COM at the time of temperature detection information TH of the basic drive signal dO to be constant at the average voltage value of the voltage signal VHV as the maximum value and the ground potential as the minimum value. That is, the control circuit 100 can also correct the basic drive signal dO according to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 including the resistance wiring 401 when the voltage value of the drive signal COM is the voltage value obtained by dividing the sum of the voltage value of the voltage signal VHV as the maximum voltage that the drive circuit 50 can output and the voltage value of the ground potential as the minimum voltage that the drive circuit 50 can output by 2.

[0243] Thus, the liquid ejecting apparatus 1 achieves the same effects as the liquid ejecting apparatus described in the embodiments, and does not have the configuration of the frequency measuring circuit 54, and therefore the control mechanism 10 and the liquid ejecting apparatus 1 can be further downsized.

[0244] The above describes the embodiments and modified examples, but the present application is not limited to these embodiments, and can be implemented in various ways without departing from the gist thereof. For example, the above-described embodiments can be appropriately combined.

[0245] The present application includes a configuration substantially the same as the configuration described in the embodiments (for example, a configuration in which the function, method, and result are the same, or a configuration in which the purpose and effect are the same). In addition, the present application includes a configuration in which a non-essential part of the configuration described in the embodiments is replaced. In addition, the present application includes a configuration that can achieve the same effects as the configuration described in the embodiments or a configuration that can achieve the same purpose. In addition, the present application includes a configuration to which a publicly known technology is added to the configuration described in the embodiments.

[0246] The following can be derived from the above-described embodiments.

[0247] One embodiment of a liquid ejecting apparatus includes a drive signal output circuit that outputs a drive signal, and a print head that receives the drive signal and ejects a liquid. The print head includes a piezoelectric element that includes a first electrode, a second electrode, and a piezoelectric body, the piezoelectric body is positioned between the first electrode and the second electrode in a stacking direction in which the first electrode, the second electrode, and the piezoelectric body are stacked, the piezoelectric element receives the drive signal and is driven, a vibration plate that is positioned on one side in the stacking direction with respect to the piezoelectric element and is deformed by driving of the piezoelectric element, a pressure chamber substrate that is positioned on the one side in the stacking direction with respect to the vibration plate and is provided with a plurality of pressure chambers whose volumes change in accordance with the deformation of the vibration plate, a switching circuit that switches whether or not the drive signal is supplied to the piezoelectric element, a wiring substrate that is provided with the switching circuit, and a temperature detection portion that is positioned on the other side in the stacking direction with respect to the vibration plate, is electrically connected to the wiring substrate, and detects temperature information of the pressure chambers. The drive signal output circuit includes a modulation circuit that outputs a modulation signal obtained by modulating a base drive signal that is a basis of the drive signal, an amplification circuit that outputs an amplified modulation signal obtained by amplifying the modulation signal, a smoothing circuit that outputs the drive signal obtained by smoothing the amplified modulation signal, a feedback circuit that feeds back the drive signal to the modulation circuit, and a base drive signal output circuit that outputs the base drive signal that is corrected in accordance with the temperature information. The frequency of the amplified modulation signal when the temperature detection portion detects the temperature information in which the base drive signal output circuit is used to correct the base drive signal is higher than the frequency of the amplified modulation signal when the temperature detection portion detects the temperature information in which the base drive signal output circuit is not used to correct the base drive signal.

[0248] According to the liquid ejecting apparatus, the temperature information of the pressure chamber can be detected with high precision by providing the temperature detection portion inside the print head, and the pulsating voltage superimposed on the drive signal input to the print head when the temperature detection portion detects the temperature information in which the base drive signal output circuit is used to correct the base drive signal can be reduced by making the frequency of the amplified modulation signal when the temperature detection portion detects the temperature information in which the base drive signal output circuit is used to correct the base drive signal higher than the frequency of the amplified modulation signal when the temperature detection portion detects the temperature information in which the base drive signal output circuit is not used to correct the base drive signal. As a result, the possibility that the temperature information of the base drive signal output circuit used to correct the base drive signal and the pulsating voltage superimposed on the drive signal interfere with each other is reduced.

[0249] In one embodiment of the liquid ejecting apparatus described above, at least a part of the temperature detection portion can be stacked on the vibration plate.

[0250] According to the liquid ejecting apparatus, the temperature detecting portion can be disposed closer to the pressure chamber, and the temperature detecting portion can further improve the detection accuracy of the temperature of the pressure chamber.

[0251] In one embodiment of the liquid ejecting apparatus described above, the base drive signal output circuit can correct the base drive signal based on the temperature information detected by the temperature detecting portion during a period in which the drive signal output circuit outputs the drive signal having a constant voltage value.

[0252] According to the liquid ejecting apparatus, when the temperature detecting portion detects the temperature information used by the base drive signal output circuit to correct the base drive signal, the likelihood of the temperature information being interfered with by the drive signal is reduced.

[0253] In one embodiment of the liquid ejecting apparatus described above, the base drive signal output circuit can correct the base drive signal based on the temperature information detected by the temperature detecting portion when the frequency of the amplified modulation signal is the maximum.

[0254] According to the liquid ejecting apparatus, the pulsating voltage overlapping the drive signal can be further reduced.

[0255] In one embodiment of the liquid ejecting apparatus described above, the base drive signal output circuit can correct the base drive signal based on the temperature information detected by the temperature detecting portion when the voltage value of the drive signal is a voltage value obtained by dividing the sum of the maximum voltage value that the drive signal output circuit can output and the minimum voltage value that the drive signal output circuit can output by 2.

[0256] According to the liquid ejecting apparatus, the pulsating voltage overlapping the drive signal can be further reduced without detecting the frequency of the amplified modulation signal.

[0257] A print head of one embodiment is a print head that receives a drive signal output from a drive signal output circuit and ejects liquid, in which the drive signal output circuit includes a modulation circuit that outputs a modulation signal obtained by modulating a base drive signal, an amplification circuit that outputs an amplified modulation signal obtained by amplifying the modulation signal, a smoothing circuit that outputs the drive signal obtained by smoothing the amplified modulation signal, a feedback circuit that feeds back the drive signal to the modulation circuit, and a base drive signal output circuit that outputs the base drive signal which is the basis of the drive signal, after correction in accordance with temperature information output from the print head. The print head includes a piezoelectric element including a first electrode, a second electrode, and a piezoelectric body, the piezoelectric body is positioned between the first electrode and the second electrode in a stacking direction in which the first electrode, the second electrode, and the piezoelectric body are stacked, the piezoelectric element receives the drive signal to be driven, a vibration plate positioned on one side in the stacking direction with respect to the piezoelectric element and deformed by driving of the piezoelectric element, a pressure chamber substrate positioned on the one side in the stacking direction with respect to the vibration plate and provided with a plurality of pressure chambers whose volumes change in accordance with the deformation of the vibration plate, a switching circuit that switches whether or not to supply the drive signal to the piezoelectric element, a wiring substrate provided with the switching circuit, and a temperature detection portion positioned on the other side in the stacking direction with respect to the vibration plate, electrically connected to the wiring substrate, and detecting the temperature information of the pressure chamber. The frequency of the amplified modulation signal when the temperature information detected by the temperature detection portion is output to the base drive signal output circuit is higher than the frequency of the amplified modulation signal when the temperature information detected by the temperature detection portion is not output to the base drive signal output circuit.

[0258] According to the print head, the temperature information of the pressure chamber can be detected with high accuracy by providing the temperature detection portion inside the print head, and the pulsating voltage superimposed on the drive signal input to the print head when the temperature information detected by the temperature detection portion is input to the base drive signal output circuit can be reduced by making the frequency of the amplified modulation signal when the temperature information detected by the temperature detection portion is output to the base drive signal output circuit higher than the frequency of the amplified modulation signal when the temperature information detected by the temperature detection portion is not output to the base drive signal output circuit. As a result, the accuracy of the temperature information detected by the temperature detection portion and output to the drive signal output circuit is improved.

[0259] In one embodiment of the above print head, at least part of the temperature detection portion can be stacked on the vibration plate.

[0260] According to the print head, the temperature detection portion can be positioned closer to the pressure chamber, and the accuracy of the temperature detection portion in detecting the temperature of the pressure chamber can be further improved.

[0261] In one embodiment of the above-described print head, the temperature information detected by the temperature detection section can be output to the basic drive signal output circuit during a period in which the drive signal output circuit outputs the drive signal at a constant voltage value.

[0262] According to this print head, when the temperature detection section detects temperature information of the basic drive signal output circuit for correcting the basic drive signal, the temperature information has a reduced possibility of being interfered with by the drive signal.

[0263] In one embodiment of the above-described print head, the temperature information detected by the temperature detection section can be output to the basic drive signal output circuit when the frequency of the amplified modulation signal is the maximum.

[0264] According to this print head, the pulsating voltage overlapping the drive signal can be further reduced without detecting the frequency of the amplified modulation signal, and the signal accuracy of the output temperature information is improved.

[0265] In one embodiment of the above-described print head, the temperature information detected by the temperature detection section can be output to the basic drive signal output circuit when the voltage value of the drive signal is a voltage value obtained by dividing the sum of the maximum voltage value that the drive signal output circuit can output and the minimum voltage value that the drive signal output circuit can output by 2.

[0266] According to this print head, the pulsating voltage overlapping the drive signal can be further reduced without detecting the frequency of the amplified modulation signal, and the signal accuracy of the output temperature information is improved.

Claims

1. A liquid ejection device, characterized in that, have: Drive signal output circuit, outputs drive signal; as well as The print head receives the drive signal and ejects liquid. The printhead includes: A piezoelectric element includes a first electrode, a second electrode, and a piezoelectric body. In the stacking direction of the first electrode, the second electrode, and the piezoelectric body, the piezoelectric body is located between the first electrode and the second electrode. The piezoelectric element receives the driving signal to be driven. The vibrating plate is located on one side of the stacking direction relative to the piezoelectric element and deforms under the drive of the piezoelectric element; A pressure chamber substrate is located on one side of the stacking direction relative to the vibrating plate, and is provided with a plurality of pressure chambers whose volume varies according to the deformation of the vibrating plate; A switching circuit to switch whether to supply the drive signal to the piezoelectric element; Wiring substrate, provided with the aforementioned switching circuit; and The temperature detection unit is located on the opposite side of the stacking direction relative to the vibrating plate, and is electrically connected to the wiring substrate, and detects the temperature information of the pressure chamber. The drive signal output circuit includes: The modulation circuit outputs a modulated signal after modulating the base drive signal that forms the basis of the drive signal. An amplifier circuit outputs an amplified modulated signal after amplifying the modulated signal; A smoothing circuit outputs a smoothed drive signal for the amplified and modulated signal; The feedback circuit feeds the driving signal back to the modulation circuit; and The basic drive signal output circuit outputs the basic drive signal corrected according to the temperature information. The frequency of the amplified modulation signal detected by the temperature detection unit when the basic drive signal output circuit is used to correct the temperature information of the basic drive signal is higher than the frequency of the amplified modulation signal detected by the temperature detection unit when the basic drive signal output circuit is not used to correct the temperature information of the basic drive signal.

2. The liquid ejection device according to claim 1, characterized in that, At least a portion of the temperature detection unit is stacked on the vibrating plate.

3. The liquid ejection device according to claim 1, characterized in that, During the period when the drive signal output circuit outputs a drive signal with a constant voltage value, the basic drive signal output circuit corrects the basic drive signal based on the temperature information detected by the temperature detection unit.

4. The liquid ejection device according to any one of claims 1 to 3, characterized in that, When the frequency of the amplified modulation signal is at its maximum, the basic drive signal output circuit corrects the basic drive signal based on the temperature information detected by the temperature detection unit.

5. The liquid ejection device according to any one of claims 1 to 3, characterized in that, When the voltage value of the drive signal is the sum of the maximum voltage that the drive signal output circuit can output and the minimum voltage that the drive signal output circuit can output, divided by 2, the basic drive signal output circuit corrects the basic drive signal based on the temperature information detected by the temperature detection unit.

6. A printhead, characterized in that, It receives the drive signal output from the drive signal output circuit and sprays out liquid. The drive signal output circuit includes: The modulation circuit outputs a modulated signal after modulating the basic drive signal; An amplifier circuit outputs an amplified modulated signal after amplifying the modulated signal; A smoothing circuit outputs a smoothed drive signal for the amplified and modulated signal; The feedback circuit feeds the driving signal back to the modulation circuit; and The basic drive signal output circuit outputs a basic drive signal, which is corrected based on the temperature information output by the printhead and serves as the basis for the drive signal. The printhead includes: A piezoelectric element includes a first electrode, a second electrode, and a piezoelectric body. In the stacking direction of the first electrode, the second electrode, and the piezoelectric body, the piezoelectric body is located between the first electrode and the second electrode. The piezoelectric element receives the driving signal to be driven. The vibrating plate is located on one side of the stacking direction relative to the piezoelectric element and deforms under the drive of the piezoelectric element; A pressure chamber substrate is located on one side of the stacking direction relative to the vibrating plate, and is provided with a plurality of pressure chambers whose volume varies according to the deformation of the vibrating plate; A switching circuit to switch whether to supply the drive signal to the piezoelectric element; Wiring substrate, provided with the aforementioned switching circuit; and The temperature detection unit is located on the opposite side of the vibrating plate in the stacking direction and is electrically connected to the wiring substrate, and detects the temperature information of the pressure chamber. The frequency of the amplified modulation signal when the temperature information detected by the temperature detection unit is output to the basic drive signal output circuit is higher than the frequency of the amplified modulation signal when the temperature information detected by the temperature detection unit is not output to the basic drive signal output circuit.

7. The printhead according to claim 6, characterized in that, At least a portion of the temperature detection unit is stacked on the vibrating plate.

8. The printhead according to claim 6, characterized in that, During the period when the drive signal output circuit outputs a drive signal with a constant voltage value, the temperature information detected by the temperature detection unit is output to the basic drive signal output circuit.

9. The printhead according to any one of claims 6 to 8, characterized in that, When the frequency of the amplified modulation signal is at its maximum, the temperature information detected by the temperature detection unit is output to the basic drive signal output circuit.

10. The printhead according to any one of claims 6 to 8, characterized in that, When the voltage value of the drive signal is the sum of the maximum voltage that the drive signal output circuit can output and the minimum voltage that the drive signal output circuit can output, divided by 2, the temperature information detected by the temperature detection unit is output to the basic drive signal output circuit.

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