Printhead and liquid ejection device

Abstract

The present application provides a printing head and a liquid ejection device capable of improving the ejection accuracy of ejected ink in a configuration in which a temperature sensing portion is provided inside. In the printing head, an ejection module that receives a corrected drive signal and ejects a liquid includes: a piezoelectric element that receives a drive signal and is driven, in which a piezoelectric body is located between a first electrode and a second electrode in a stacking direction; a vibration plate that is located on one side of the piezoelectric element in the stacking direction and is deformed by the driving of the piezoelectric element; a pressure chamber substrate that is located on one side of the vibration plate in the stacking direction and is provided with a pressure chamber whose volume changes due to the deformation of the vibration plate; a nozzle that ejects the liquid according to the volume change of the pressure chamber; and a temperature detection portion that is located on the other side of the vibration plate in the stacking direction and detects the temperature of the pressure chamber, the drive signal being corrected based on N pieces of temperature information (N is a natural number of 2 or more) corresponding to the temperature of the pressure chamber detected at different timings from the temperature detection portion.

Description

Technical Field

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

[0002] A known liquid ejection device comprises a printhead having a piezoelectric element, a pressure chamber, and a nozzle communicating with the pressure chamber. The printhead, driven by the piezoelectric element, changes the volume of the pressure chamber, thereby ejecting liquid supplied to the pressure chamber from the nozzle. In liquid ejection devices with such printheads, a technique is known to achieve ejection control at a temperature suitable for the ink by driving and controlling the piezoelectric element based on the temperature of the ink stored in the printhead.

[0003] For example, Patent Document 1 discloses a technology as follows: by providing a temperature sensing unit inside a printhead having a piezoelectric element, a pressure chamber, and a nozzle to detect the temperature of the pressure chamber storing ink, the temperature difference between the temperature detected by the temperature sensing unit and the temperature inside the pressure chamber can be reduced, thereby improving the detection accuracy of the temperature of the ink stored in the pressure chamber.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2022-124599

[0005] However, in the liquid ejection device described in Patent Document 1, the configuration in which a temperature sensing unit is provided inside the printhead is still insufficient in terms of improving the ejection accuracy of the ejected ink, and there is room for improvement. Summary of the Invention

[0006] One aspect of the printhead according to the present invention includes an ejection module that ejects liquid upon receiving a corrected drive signal. The ejection module comprises: a piezoelectric element that receives the drive signal and is driven thereon, and includes a first electrode, a second electrode, and a piezoelectric body, wherein the piezoelectric body is located 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; a vibrating plate located on one side of the stacking direction relative to the piezoelectric element, and deformed by the drive of the piezoelectric element; a pressure chamber substrate located on one side of the stacking direction relative to the vibrating plate, and having a pressure chamber whose volume changes due to the deformation of the vibrating plate; a nozzle that ejects liquid in response to the change in the volume of the pressure chamber; and a temperature detection unit located on the other side of the stacking direction relative to the vibrating plate, which detects the temperature of the pressure chamber. The drive signal is corrected based on N temperature information (N being a natural number greater than or equal to 2) corresponding to the temperature of the pressure chamber detected by the temperature detection unit at different timing intervals.

[0007] One aspect of the liquid ejection device according to the present invention comprises: a drive signal output circuit for outputting a calibrated drive signal; a calibration unit for calibrating the drive signal; and a printhead for receiving the drive signal and ejecting liquid, the printhead having an ejection module for receiving the drive signal and ejecting liquid, the ejection module comprising: a piezoelectric element for receiving the drive signal and being driven, and including a first electrode, a second electrode, and a piezoelectric body, wherein the piezoelectric body is located between the first electrode and the second electrode in the stacking direction of the first electrode, the second electrode, and the piezoelectric body; and a vibrating plate relative to the piezoelectric element. An electrical component is located on one side of the stacking direction and deforms by being driven by 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 pressure chamber whose volume changes due to the deformation of the vibrating plate; a nozzle ejects liquid in response to the change in the volume of the pressure chamber; and a temperature detection unit is located on the other side of the stacking direction relative to the vibrating plate and detects the temperature of the pressure chamber, and a correction unit corrects the drive signal based on N temperature information (N is a natural number greater than 2) corresponding to the temperature of the pressure chamber detected by the temperature detection unit at different timings. Attached Figure Description

[0008] Figure 1 This is a diagram showing the general structure of a liquid ejection device.

[0009] Figure 2 This is a diagram showing the functional configuration of a liquid ejection device.

[0010] Figure 3 This is a diagram showing an example of the signal waveform of the drive signal COM.

[0011] Figure 4 This is a diagram showing the configuration of the drive signal selection circuit.

[0012] Figure 5 This is a diagram showing an example of the decoded content in the decoder.

[0013] Figure 6 This is a diagram showing the configuration of the selection circuit.

[0014] Figure 7 This is a diagram used to illustrate the operation of the drive signal selection circuit.

[0015] Figure 8 This is an exploded perspective view showing the structure of the ejection module.

[0016] Figure 9 This is a top view of the ejection module 22.

[0017] Figure 10 It is shown Figure 9The cross-sectional view of section Aa shown.

[0018] Figure 11 yes Figure 10 Detailed diagram of the main parts.

[0019] Figure 12 It is shown Figure 9 The cross-sectional view of section Bb shown.

[0020] Figure 13 This is a diagram showing the functional structure of the temperature information output circuit.

[0021] Figure 14 This diagram illustrates an example of the timing for acquiring temperature information tc using a temperature information output circuit.

[0022] Figure 15 This diagram illustrates an example of how the temperature information output circuit generates the temperature information signal TI.

[0023] Explanation of reference numerals in the attached figures

[0024] 1. Liquid ejection device; 2. Ink container; 10. Control mechanism; 20. Printhead; 21. Carriage; 22. Ejection module; 24. Temperature detection circuit; 26. Temperature information output circuit; 30. Moving mechanism; 31. Carriage motor; 32. Circular belt; 40. Conveying mechanism; 41. Conveying motor; 42. Conveying roller; 50. Drive circuit; 52. Reference voltage signal output circuit; 60. Piezoelectric element; 90. Linear encoder; 100. Control circuit; 200. Drive signal selection circuit; 210. Selection control circuit. ; 212 Shift register; 214 Latch circuit; 216 Decoder; 230 Selection circuit; 232 Inverter; 234 Transmission gate; 310 Pressure chamber substrate; 311 Partition wall; 312 Pressure chamber; 312a, 312b ends; 315 Connecting plate; 316 Nozzle connecting channel; 317 First manifold section; 318 Second manifold section; 319 Supply connecting channel; 320 Nozzle plate; 321 Nozzle; 330 Protective substrate; 331 Holding section; 332 Through hole; 34 0. Housing component; 341. Receiving part; 342. Third manifold part; 343. Connection port; 344. Supply port; 345. Moldable substrate; 346. Sealing film; 347. Fixing substrate; 348. Opening; 349. Moldable part; 350. Vibrating plate; 351. Elastic membrane; 352. Insulating film; 360. Electrode; 360a, 360b ends; 370. Piezoelectric element; 370a, 370b ends; 371. Groove; 380. Electrode; 380a, 380b ends; 385. Wiring part ; 391 Individual lead electrode; 392 Shared lead electrode; 392a, 392b Extension setting parts; 393, 393a, 393b Measurement lead electrodes; 400 Manifold; 401 Resistor wiring; 410 Active part; 415 Inactive part; 420 Wiring board; 421 Integrated circuit; 500 Control circuit; 510-1 to 510-n Amplifier circuit; 530 Multiplexer; 540 AD conversion circuit; 550 Storage circuit; 600 Ejection part; P dielectric. Detailed Implementation

[0025] The preferred embodiments of the present invention will now be described using the accompanying drawings. The drawings are provided for ease of explanation. It should be noted that the embodiments described below are not intended to unduly limit the scope of the invention as defined in the claims. Furthermore, not all of the components described below are necessarily essential elements of the present invention.

[0026] 1. Structure of the liquid ejection device

[0027] Figure 1This diagram shows a schematic configuration of the liquid ejection device 1. In this embodiment, the liquid ejection device 1 is described using a serial printing inkjet printer as an example. This serial printing inkjet printer forms an image on the medium P by reciprocating a carriage 21 carrying a printhead 20 that ejects ink (an example of liquid) along the scanning axis and ejecting ink onto the medium P being transported in the transport direction. The medium P used in this liquid ejection device 1 can be any printing material such as printing paper, resin film, or fabric.

[0028] like Figure 1 As shown, the liquid ejection device 1 includes an ink container 2, a control mechanism 10, a carriage 21, a moving mechanism 30, and a conveying mechanism 40.

[0029] The ink container 2 stores various types of ink that can be sprayed onto the medium P. Examples of ink colors stored in the ink container 2 include black, cyan, magenta, yellow, red, and gray. The ink container 2 for storing such ink can be an ink cartridge, a pouch-shaped ink bag made of a flexible film, or an ink canister for refilling ink.

[0030] The control mechanism 10 includes, for example, processing circuits such as a CPU (Central Processing Unit), an FPGA (Field Programmable Gate Array), and storage circuits such as a semiconductor memory, to control the various elements of the liquid ejection device 1, including the print head 20.

[0031] The carriage 21 carries the printhead 20 and is fixed to the annular belt 32 included in the moving mechanism 30. It should be noted that the ink container 2 can also be mounted on the carriage 21.

[0032] The control signal Ctrl-H for controlling the printhead 20 and the drive signal COM for driving the printhead 20, output from the control mechanism 10, are input to the printhead 20 mounted on the carriage 21. Furthermore, ink stored in the ink container 2 is supplied to the printhead 20 via a tube (not shown). Then, the printhead 20 ejects the ink supplied from the ink container 2 based on the input control signal Ctrl-H and drive signal COM.

[0033] The moving mechanism 30 includes a carriage motor 31 and an annular belt 32. The carriage motor 31 operates based on a control signal Ctrl-C input from the control mechanism 10. The annular belt 32 rotates as the carriage motor 31 operates. As a result, the carriage 21, fixed to the annular belt 32, reciprocates on the scanning axis. That is, the carriage 21 reciprocates along the scanning axis that intersects the conveying direction of the conveying medium P.

[0034] The conveying mechanism 40 includes a conveying motor 41 and a conveying roller 42. The conveying motor 41 operates based on a control signal Ctrl-T input from the control mechanism 10. The conveying roller 42 rotates in tandem with the operation of the conveying motor 41. Along with the rotation of the conveying roller 42, the medium P is conveyed in the conveying direction.

[0035] As described above, in the liquid ejection device 1, the delivery mechanism 40 transports the medium P and the moving mechanism 30 reciprocates the carriage 21. The print head 20 mounted on the carriage 21 ejects ink onto the medium P, so that the ink falls at any position on the surface of the medium P and forms the desired image on the medium P.

[0036] 2. Functional Composition of Liquid Ejection Device

[0037] Next, the functional configuration of the liquid ejection device 1 will be explained. Figure 2 This is a diagram showing the functional configuration of the liquid ejection device 1. (See diagram below.) Figure 2 As shown, the liquid ejection device 1 includes a control mechanism 10, a print head 20, a carriage motor 31, a conveyor motor 41, and a linear encoder 90.

[0038] The control mechanism 10 includes a drive circuit 50, a reference voltage signal output circuit 52, and a control circuit 100. The control circuit 100 includes, for example, processing circuits such as a CPU or FPGA, and storage circuits such as semiconductor memory. Image information signals, including image data, are input to the control circuit 100 from external devices such as a host computer that are communicatively connected to the liquid ejection device 1. Based on the input image information signals, the control circuit 100 generates various signals for controlling the liquid ejection device 1 and outputs them to the corresponding components.

[0039] In a specific example, in addition to the image information signal mentioned above, a detection signal based on the scanning position of the carriage 21 is also input from the linear encoder 90 to the control circuit 100. The control circuit 100 determines the scanning position of the print head 20 mounted on the carriage 21 based on the input detection signal. Then, the control circuit 100 generates and outputs various signals corresponding to the scanning position of the print head 20 and the image information signal.

[0040] 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 based on the scanning position of the print head 20, and outputs it to the carriage motor 31. As a result, the carriage motor 31 operates, controlling the movement and scanning position of the print head 20 mounted on the carriage 21 along the scanning axis. Furthermore, the control circuit 100 generates a control signal Ctrl-T for controlling the transport of the medium P, and outputs it to the transport motor 41. As a result, the transport motor 41 operates, controlling the movement of the medium P along the transport direction. It should be noted that the control signal Ctrl-C can also be input to the carriage motor 31 after signal conversion via a driver circuit (not shown), and the control signal Ctrl-T can also be input to the transport motor 41 after signal conversion via a driver circuit (not shown).

[0041] In addition, the control circuit 100 generates printing data signals SI1 to SIn, change signals CH, latch signals LAT, and clock signals SCK as control signals Ctrl-H for controlling the print head 20 based on the image information signals input from external devices and the scanning position of the print head 20 input from the linear encoder 90, and outputs them to the print head 20.

[0042] Furthermore, the control circuit 100 generates a temperature acquisition request signal TD at a predetermined timing to acquire the temperature of the printhead 20 and outputs it to the printhead 20. Additionally, the printhead 20 outputs a temperature information signal TI in response to the temperature acquisition request signal TD, which is then input to the control circuit 100. That is, a temperature information signal TI containing temperature information of the printhead 20 is input to the control circuit 100. Then, the control circuit 100 corrects the control signals Ctrl-H, Ctrl-C, and Ctrl-T based on the input temperature information signal TI.

[0043] Furthermore, the control circuit 100 outputs the basic drive signal dO, which is a digital signal, to the drive circuit 50 as the control signal Ctrl-H. After performing digital-to-analog conversion on the input basic drive signal dO, the drive circuit 50 amplifies the converted analog signal using Class D amplification to generate the drive signal COM, which is then output to the print head 20. In other words, the basic drive signal dO output by the control circuit 100 is a digital signal that defines the waveform of the drive signal COM. Here, the control circuit 100 corrects the basic drive signal dO based on the input temperature information signal TI. That is, the drive circuit 50 outputs the drive signal COM after correction based on the temperature information signal TI. It should be noted that the basic drive signal dO only needs to define the waveform of the drive signal COM output by the drive circuit 50; it can also be an analog signal.

[0044] 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 by the reference voltage signal output circuit 52 is a potential signal that serves as a reference for driving the piezoelectric element 60 (described later). For example, it can be a signal that is constant at ground potential, or it can be a DC voltage signal that is constant at potentials such as 5.5V or 6V.

[0045] The printhead 20 has ejection modules 22-1 to 22-n and a temperature information output circuit 26. In addition, each of the ejection modules 22-1 to 22-n includes a drive signal selection circuit 200, a temperature detection circuit 24, and multiple piezoelectric elements 60.

[0046] The following signals are input to the ejection module 22-1: printing data signal SI1, change signal CH, latch signal LAT and clock signal SCK output by control circuit 100; drive signal COM output by drive circuit 50; and reference voltage signal VBS output by reference voltage signal output circuit 52.

[0047] The clock signal SCK, latch signal LAT, change signal CH, print data signal SI1, and 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 selects or deselects the signal waveform of the drive signal COM based on the input clock signal SCK, latch signal LAT, change signal CH, and print data signal SI1, thereby generating a drive signal VOUT corresponding to each of the multiple piezoelectric elements 60, and outputting it individually to one end of the corresponding piezoelectric element 60. Furthermore, a reference voltage signal VBS is commonly input to the other end of the multiple piezoelectric elements 60. Each of the multiple piezoelectric elements 60 is driven according to the potential difference between the individually input drive signal VOUT and the commonly input reference voltage signal VBS. The ejection module 22-1 ejects an amount of ink corresponding to the drive of the piezoelectric element 60.

[0048] The temperature detection circuit 24 of the ejection module 22-1 detects the temperature of the ejection module 22-1 and acquires it as temperature information tc1. Then, the temperature detection circuit 24 of the ejection module 22-1 generates a temperature detection signal TC1 containing the acquired temperature information tc1 and outputs it to the temperature information output circuit 26.

[0049] Here, the only difference between the ejection modules 22-2 to 22-n is the input signal and the output signal. Otherwise, they have the same structure as the ejection module 22-1 and perform the same actions.

[0050] Specifically, the ejection module 22-p (where p is any one of 1 to n) receives a clock signal SCK, a latch signal LAT, a change signal CH, a print data signal SIp, a drive signal COM, and a reference voltage signal VBS. Then, the drive signal selection circuit 200 of the ejection module 22-p selects or deselects the signal waveform of the drive signal COM based on the input clock signal SCK, latch signal LAT, change signal CH, and print data signal SIp, thereby generating a drive signal VOUT corresponding to each of the plurality of piezoelectric elements 60. The drive signal VOUT generated by the drive signal selection circuit 200 is individually input to one end of the corresponding piezoelectric element 60. Furthermore, the reference voltage signal VBS is collectively input to the other end of the plurality of piezoelectric elements 60 of the ejection module 22-p. Thus, each of the plurality of piezoelectric elements 60 of the ejection module 22-p is driven, ejecting an amount of ink from the ejection module 22-p corresponding to the driving of the piezoelectric element 60.

[0051] Furthermore, the temperature detection circuit 24 of the ejection module 22-p detects the temperature of the ejection module 22-p and acquires it as temperature information tcp. Then, the temperature detection circuit 24 of the ejection module 22-p generates a temperature detection signal TCp containing the acquired temperature information tcp and outputs it to the temperature information output circuit 26.

[0052] In the following description, without distinguishing between the ejection modules 22-1 to 22-n, they will sometimes be simply referred to as ejection module 22. In this case, the description will focus on the following: clock signal SCK, latch signal LAT, change signal CH, printing data signal SI, drive signal COM, and reference voltage signal VBS are input to ejection module 22, and temperature information tc corresponding to the temperature of ejection module 22 is acquired and output as a temperature detection signal TC containing the temperature information tc.

[0053] The temperature detection signals TC1 to TCn output by the ejection modules 22-1 to 22-n, the temperature acquisition request signal TD output by the control circuit 100, and the latch signal LAT are input to the temperature information output circuit 26. Based on the temperature acquisition request signal TD, the temperature information output circuit 26 acquires the temperature information tc1 to tcn contained in each of the temperature detection signals TC1 to TCn at a timing specified by the latch signal LAT, and outputs the temperature information signal TI corresponding to the acquired temperature information tc1 to tcn.

[0054] As described above, the liquid ejection device 1 of this embodiment includes: a control circuit 100 that outputs a clock signal SCK, a latch signal LAT, a change signal CH, and a printing data signal SI; a drive circuit 50 that outputs a drive signal COM; and a printhead 20 that receives the clock signal SCK, the latch signal LAT, the change signal CH, the printing data signal SI, and the drive signal COM and ejects ink. In this liquid ejection device 1, the clock signal SCK, the latch signal LAT, the change signal CH, and the printing data signal SI output by the control circuit 100, and the drive signal COM output by the drive circuit 50 are corrected according to the temperature information signal TI output by the printhead 20. That is, the liquid ejection device 1 of this embodiment includes: a drive circuit 50 that outputs a drive signal COM that is corrected based on a temperature information signal TI; a control circuit 100 that corrects the drive signal COM; and a print head 20 that receives the corrected drive signal COM and ejects ink. The print head 20 includes: an ejection module 22 that receives the corrected drive signal COM and ejects ink; and a temperature information output circuit 26 that outputs a temperature information signal TI that indicates the temperature of the ejection module 22.

[0055] 3. Functional Composition of the Drive Signal Selection Circuit

[0056] Next, the configuration and operation of the drive signal selection circuit 200 in the ejection module 22 will be explained. As previously described, the drive signal selection circuit 200 in the ejection module 22 selects or deselects the signal waveforms included in the drive signal COM based on the clock signal SCK, the printing data signal SI, the latch signal LAT, and the change signal CH, thereby generating a drive signal VOUT and outputting it to the corresponding piezoelectric element 60. Therefore, when explaining the configuration and operation of the drive signal selection circuit 200, an example of the waveform of the drive signal COM input to the drive signal selection circuit 200 will be explained first.

[0057] Figure 3 This is a diagram showing an example of the signal waveform of the drive signal COM. (See diagram for example.) Figure 3 As shown, the drive signal COM includes: a trapezoidal waveform Adp, configured for the period td1 from the rise of the latch signal LAT to the rise of the change signal CH; a trapezoidal waveform Bdp, configured for the period td2 from the rise of the change signal CH to the rise of the next change signal CH; and a trapezoidal waveform Cdp, configured for the period td3 from the rise of the change signal CH to the rise of the latch signal LAT.

[0058] The trapezoidal waveform Adp is a signal waveform that drives the piezoelectric element 60 to eject a predetermined amount of ink, and the trapezoidal waveform Bdp is a signal waveform that drives the piezoelectric element 60 to eject a smaller amount of ink than the predetermined amount. Furthermore, the trapezoidal waveform Cdp is a signal waveform that drives the piezoelectric element 60 to the point of not ejecting ink, and is used to reduce the risk of increased ink viscosity near the nozzle opening by vibrating the ink near the nozzle opening corresponding to the piezoelectric element 60. Moreover, the trapezoidal waveforms Adp, Bdp, and Cdp are signal waveforms whose respective start and end timing voltage values ​​are all voltage Vc. That is, each of the trapezoidal waveforms Adp, Bdp, and Cdp starts and ends with voltage Vc.

[0059] Here, in the following description, the amount of ink ejected in the case of a trapezoidal waveform Adp being supplied to the piezoelectric element 60 is sometimes referred to as a medium amount, and the amount of ink ejected in the case of a trapezoidal waveform Bdp being supplied to the piezoelectric element 60 that is less than the predetermined amount is sometimes referred to as a small amount. Furthermore, the action used to vibrate the ink near the nozzle opening corresponding to the piezoelectric element 60 to prevent an increase in ink viscosity when the trapezoidal waveform Cdp is supplied to the piezoelectric element 60 is sometimes referred to as micro-vibration. It should be noted that... Figure 3 The signal waveform of the drive signal COM shown is an example, but it is not limited to this. Various combinations of waveforms can be used depending on the nature of the ejected ink, the material of the medium P on which the ink lands, etc.

[0060] Therefore, the drive signal selection circuit 200 controls the amount of ink ejected in period tp by selecting or deselecting the trapezoidal waveforms Adp, Bdp, and Cdp included in the drive signal COM during the period tp, which includes the aforementioned periods td1, td2, and td3. In other words, it controls the size of the dots formed on the medium P during period tp. The period tp, which includes the periods td1, td2, and td3, is the dot formation period for forming dots of a predetermined size on the medium P, which corresponds to the ink ejection period for ejecting ink onto the medium P. That is, the latch signal LAT specifies the period tp, which corresponds to the ink ejection period from the ejection module 22.

[0061] Next, the configuration and operation of the drive signal selection circuit 200, which generates the drive signal VOUT by selecting or not selecting the signal waveform included in the drive signal COM, will be explained. Figure 4 This is a diagram showing the configuration of the drive signal selection circuit 200. (As shown) Figure 4 As shown, the drive signal selection circuit 200 includes a selection control circuit 210 and a plurality of selection circuits 230, the same number as the plurality of piezoelectric elements 60. It should be noted that the following description will focus on the case where the ejection module 22 has m piezoelectric elements 60.

[0062] The selection control circuit 210 receives the input clock signal SCK, printed data signal SI, latch signal LAT, and change signal CH. Furthermore, within the selection control circuit 210, each of the m piezoelectric elements 60 is provided with a shift register (S / R) 212, a latch circuit 214, and a decoder 216. That is, the drive signal selection circuit 200 includes m shift registers 212, m latch circuits 214, and m decoders 216.

[0063] The print data signal SI is input to the selection control circuit 210 synchronously with the clock signal SCK. Furthermore, the print data signal SI and each of the m piezoelectric elements 60 are serially associated with 2 bits of print data [SIH, SIL] for selecting any one of "large dot LD", "medium dot MD", "small dot SD", and "non-recording ND". The print data [SIH, SIL] included in the print data signal SI is stored in m shift registers 212 corresponding to the m piezoelectric elements 60. Specifically, the m shift registers 212 corresponding to the piezoelectric elements 60 are cascaded together, and the serially input print data signal SI is sequentially transmitted to the subsequent shift registers 212 according to the clock signal SCK. Then, the clock signal SCK stops because the print data [SIH, SIL] is stored in the corresponding shift register 212. Thus, the print data [SIH, SIL] included in the print data signal SI is stored in the corresponding shift register 212. It should be noted that in Figure 4 In order to distinguish the m shift registers 212, they are sequentially recorded as level 1, level 2, ..., level m, starting from the upstream side of the input printed data signal SI.

[0064] Each of the m latch circuits 214 latches together the printed data [SIH, SIL] held in the corresponding shift register 212 on the rising edge of the latch signal LAT. Then, the printed data [SIH, SIL] latched by the latch circuits 214 is input to the corresponding decoder 216. Figure 5 This diagram illustrates an example of the decoded content in decoder 216. Decoder 216 outputs a selection signal S with a logic level specified by the input printed data [SIH, SIL] during periods td1, td2, and td3. For example, when printed data [SIH, SIL] = [1, 0] is input to decoder 216, decoder 216 outputs the selection signal S with a logic level set to H, L, and L during periods td1, td2, and td3.

[0065] The selection signal S output by the decoder 216 is input to the selection circuit 230. The selection circuit 230 is configured corresponding to each of the m piezoelectric elements 60. That is, the drive signal selection circuit 200 has the same number of selection circuits 230 as the m piezoelectric elements 60. Figure 6 This is a diagram showing the configuration of the selection circuit 230. (As shown) Figure 6 As shown, the selection circuit 230 includes an inverter 232 and a transmission gate 234, which are NOT circuits.

[0066] The selection signal S is input to the positive control terminal (not marked with a circle) of transmission gate 234, and after its logic level is inverted by inverter 232, it is also input to the negative control terminal (marked with a circle) of transmission gate 234. Furthermore, a drive signal COM is supplied to the input terminal of transmission gate 234. Therefore, when a high-level selection signal S is input, transmission gate 234 conducts between its input and output terminals; when a low-level selection signal S is input, it does not conduct between them. That is, when the logic level of the selection signal S is high, transmission gate 234 outputs the signal waveform included in the drive signal COM from its output terminal; when the logic level of the selection signal S is low, transmission gate 234 does not output the signal waveform included in the drive signal COM from its output terminal. Thus, the drive signal selection circuit 200 outputs the signal from the output terminal of transmission gate 234 of the selection circuit 230 as the drive signal VOUT.

[0067] Here, using Figure 7 The operation of the drive signal selection circuit 200 is explained. Figure 7 This diagram illustrates the operation of the drive signal selection circuit 200. The print data signal SI is input to the selection control circuit 210 as a serial signal synchronized with the clock signal SCK. Then, the print data signal SI is sequentially transmitted in m shift registers 212 corresponding to m piezoelectric elements 60, synchronized with the clock signal SCK. Afterwards, when the input of the clock signal SCK stops, the print data [SIH, SIL] corresponding to each of the m piezoelectric elements 60 is held in the shift register 212. It should be noted that the print data signal SI is input in the order corresponding to the piezoelectric elements 60 in the m-th, ..., 2-th, and 1-th stages of the shift register 212.

[0068] Then, when the latch signal LAT rises, each latch circuit 214 latches the printed data [SIH, SIL] held in the shift register 212 together. It should be noted that... Figure 7 The LT1, LT2, ..., LTm shown represent the printed data [SIH, SIL] latched by the latch circuit 214 corresponding to the shift registers 212 of level 1, level 2, ..., level m.

[0069] Decoder 216, based on the size of the points specified by the latched print data [SIH, SIL], performs operations in periods td1, td2, and td3 respectively. Figure 5 The output select signal S is set to a logic level. Then, the selection circuit 230 selects or deselects the signal waveform included in the drive signal COM based on the logic level of the select signal S output by the decoder 216, thereby generating the drive signal VOUT.

[0070] Specifically, when printed data [SIH, SIL] = [1, 1] is input into decoder 216, decoder 216 sets the logic level of selection signal S to H, H, L levels during periods td1, td2, and td3. Consequently, selection circuit 230 selects trapezoidal waveform Adp during period td1, trapezoidal waveform Bdp during period td2, and does not select trapezoidal waveform Cdp during period td3. As a result, drive signal selection circuit 200 outputs drive signal VOUT corresponding to "large point LD".

[0071] When the drive signal VOUT corresponding to the "large dot LD" is supplied to the piezoelectric element 60, a medium amount of ink is ejected during period td1, a small amount of ink is ejected during period td2, and no ink is ejected during period td3. Thus, the medium and small amounts of ink ejected fall onto the medium P and combine, thereby forming a "large dot LD" on the medium P.

[0072] Furthermore, when printed data [SIH, SIL] = [1, 0] is input into decoder 216, decoder 216 sets the logic level of selection signal S to H, L, L levels during periods td1, td2, and td3. Consequently, selection circuit 230 selects trapezoidal waveform Adp during period td1, does not select trapezoidal waveform Bdp during period td2, and does not select trapezoidal waveform Cdp during period td3. As a result, drive signal selection circuit 200 outputs drive signal VOUT corresponding to the "midpoint MD".

[0073] When the drive signal VOUT corresponding to the "midpoint MD" is supplied to the piezoelectric element 60, a moderate amount of ink is ejected during period td1, no ink is ejected during period td2, and no ink is ejected during period td3. Thus, the moderate amount of ink ejected falls onto the medium P, forming the "midpoint MD" on the medium P.

[0074] Furthermore, when printed data [SIH, SIL] = [0, 1] is input into decoder 216, decoder 216 sets the logic level of selection signal S to L, H, L levels during periods td1, td2, and td3. Consequently, selection circuit 230 does not select trapezoidal waveform Adp during period td1, selects trapezoidal waveform Bdp during period td2, and does not select trapezoidal waveform Cdp during period td3. As a result, drive signal selection circuit 200 outputs drive signal VOUT corresponding to "small dot SD".

[0075] When the drive signal VOUT corresponding to the "small dot SD" is supplied to the piezoelectric element 60, no ink is ejected during period td1, a small amount of ink is ejected during period td2, and no ink is ejected during period td3. Thus, the small amount of ink ejected falls onto the medium P, forming the "small dot SD" on the medium P.

[0076] Furthermore, when printed data [SIH, SIL] = [0, 0] is input into decoder 216, decoder 216 sets the logic level of selection signal S to L, L, H levels during periods td1, td2, and td3. Consequently, selection circuit 230 does not select trapezoidal waveform Adp during period td1, does not select trapezoidal waveform Bdp during period td2, and selects trapezoidal waveform Cdp during period td3. As a result, drive signal selection circuit 200 outputs drive signal VOUT corresponding to "non-recording ND".

[0077] When the drive signal VOUT corresponding to "non-recording ND" is supplied to the piezoelectric element 60, no ink is ejected during period td1, no ink is ejected during period td2, and no ink is ejected during period td3. Therefore, it becomes a "non-recording ND" where ink is not ejected from the ejection section 600 and no dot is formed on the medium P. At this time, the drive signal VOUT, including a trapezoidal waveform Cdp, is input to the corresponding piezoelectric element 60. Therefore, micro-vibration is performed. As a result, the risk of increased ink viscosity near the nozzle opening of the corresponding ejection section 600 is reduced.

[0078] As described above, in the liquid ejection device 1 of this embodiment, the ejection module 22 has a piezoelectric element 60 that is driven by a drive signal COM, and ink, an example of a liquid, is ejected by the drive of the piezoelectric element 60.

[0079] 4. Structure of the ejection module

[0080] Next, the structure of the ejection module 22 of the printhead 20 will be described. Figure 8 This is an exploded perspective view showing the structure of the ejection module 22. Figure 9 This is a top view of the ejection module 22. Figure 10 It is shown Figure 9 The sectional view of section Aa shown. Figure 11 yes Figure 10 Detailed diagrams of the main parts, Figure 12 It is shown Figure 9 The diagram shows a cross-sectional view of section Bb. In describing the structure of the ejection module 22, the X-axis, Y-axis, and Z-axis, which are orthogonal to each other, are used as the three spatial axes in the following description. Furthermore, when specifying the orientation of the X-axis, Y-axis, and Z-axis, the starting side of the arrow indicating the direction along the X-axis is sometimes referred to as the -X side and the leading side as the +X side; the starting side of the arrow indicating the direction along the Y-axis is referred to as the -Y side and the leading side as the +Y side; and the starting side of the arrow indicating the direction along the Z-axis is referred to as the -Z side and the leading side as the +Z side.

[0081] like Figure 8 As shown, the ejection module 22 ejects ink from the -Z side toward the +Z side along the Z-axis. The ejection module 22 has a pressure chamber substrate 310, a connecting plate 315, a nozzle plate 320, a malleable substrate 345, a protective substrate 330, a housing component 340, a wiring substrate 420, a vibrating plate 350 (described later), and a piezoelectric element 60 (described later).

[0082] like Figure 9 As shown, on the pressure chamber substrate 310, multiple pressure chambers 312 arranged along the Y-axis are arranged in two rows along the X-axis. Here, among the two rows of pressure chambers arranged on the pressure chamber substrate 310, the pressure chamber row arranged on the +X side is sometimes referred to as the first pressure chamber row, and the pressure chamber row arranged on the -X side of the first pressure chamber row is referred to as the second pressure chamber row. It should be noted that... Figure 9 This is a top view of the ejection module 22, but it mainly shows the structure around the pressure chamber substrate 310, and omits the illustrations of the protective substrate 330 and the housing component 340.

[0083] The multiple pressure chambers 312 constituting each pressure chamber row are arranged in a straight line along the Y-axis with their positions approximately the same along the X-axis. Thus, by Figure 12The partition wall 311 shown divides adjacent pressure chambers 312 along the Y-axis. It should be noted that the arrangement of the pressure chambers 312 is not limited to the above-described arrangement. For example, the multiple pressure chambers 312 constituting each pressure chamber row can also be arranged in a staggered configuration where their positions are offset along the X-axis. Furthermore, the shape of the pressure chamber 312 is described as a rectangle whose length along the X-axis is longer than its length along the Y-axis when viewed from the +Z side. However, the shape of the pressure chamber 312 when viewed from the +Z side is not limited to this; for example, it can be a parallelogram shape, a polygon shape, a circle shape, an oval shape, etc. Here, an oval shape is a shape based on a rectangle with the two ends of the long side formed into semicircles, including rounded rectangular shapes, elliptical shapes, egg shapes, etc.

[0084] like Figure 8 as well as Figure 10 As shown, a connecting plate 315, a nozzle plate 320, and a malleable substrate 345 are stacked on the +Z side of the pressure chamber substrate 310.

[0085] A nozzle communication channel 316 is provided on the connecting plate 315, connecting the pressure chamber 312 and the nozzle 321. Furthermore, a first manifold portion 317 and a second manifold portion 318 are provided on the connecting plate 315. These two portions form part of a manifold 400 that communicates with the multiple pressure chambers 312 and functions as a shared liquid chamber. The first manifold portion 317 extends through the connecting plate 315 along the Z-axis. The second manifold portion 318 does not extend through the connecting plate 315 along the Z-axis, but is instead provided as an opening on the +Z side of the connecting plate 315.

[0086] Furthermore, on the connecting plate 315, a supply connecting channel 319, which communicates with one end of the pressure chamber 312 along the X-axis, is independently provided corresponding to each pressure chamber 312. The supply connecting channel 319 connects the second manifold section 318 and each pressure chamber 312, thereby supplying ink stored inside the manifold 400 to each pressure chamber 312. Here, it is preferable that the connecting plate 315 uses a material with approximately the same coefficient of thermal expansion as the pressure chamber substrate 310. This reduces the risk of warping of at least one of the pressure chamber substrate 310 and the connecting plate 315 due to differences in their coefficients of thermal expansion, should the temperature of the pressure chamber substrate 310 and the connecting plate 315 change.

[0087] The nozzle plate 320 is disposed on the side of the connecting plate 315 opposite to the pressure chamber base plate 310, that is, on the +Z side of the connecting plate 315. Nozzles 321 are formed on the nozzle plate 320 and communicate with each pressure chamber 312 via nozzle connecting channels 316. That is, a plurality of nozzles 321 corresponding to a plurality of pressure chambers 312 are formed on the nozzle plate 320.

[0088] Multiple nozzles 321 are arranged along the Y-axis to form a nozzle array. Two rows of nozzles 321 are formed on the nozzle plate 320 along the X-axis. One row of nozzles corresponds to the first pressure chamber array, and the other corresponds to the second pressure chamber array. The multiple nozzles 321 in each nozzle array are arranged along the Y-axis with their positions approximately the same along the X-axis. It should be noted that the arrangement of the nozzles 321 is not limited to the above-described arrangement; for example, the multiple nozzles 321 forming each nozzle array can also be arranged in a staggered configuration with their positions offset along the X-axis. Here, it is preferable that the nozzle plate 320 uses a material with approximately the same coefficient of thermal expansion as the connecting plate 315. This reduces the risk of warping of at least one of the nozzle plate 320 and the connecting plate 315 due to differences in their coefficients of thermal expansion when the temperatures of the nozzle plate 320 and the connecting plate 315 change.

[0089] A malleable substrate 345 is disposed together with a nozzle plate 320 on the side of the connecting plate 315 opposite to the pressure chamber substrate 310, i.e., the +Z side of the connecting plate 315. Furthermore, the malleable substrate 345 is disposed around the nozzle plate 320 to seal the openings of the first manifold portion 317 and the second manifold portion 318 disposed on the connecting plate 315. The malleable substrate 345 includes a flexible sealing film 346 and a fixing substrate 347 made of a rigid material. Additionally, an opening 348 is formed on the malleable substrate 345 in the region opposite the manifold 400, where the fixing substrate 347 is completely removed in the thickness direction. That is, one side of the manifold 400 becomes a malleable portion 349 sealed only by the flexible sealing film 346.

[0090] On the other hand, the vibrating plate 350 and the plurality of piezoelectric elements 60 that apply pressure to the ink stored inside the pressure chamber 312 by flexing and deforming the vibrating plate 350 are located on the side of the pressure chamber substrate 310 opposite to the nozzle plate 320, i.e., the -Z side of the pressure chamber substrate 310. On the -Z side of the vibrating plate 350, the plurality of piezoelectric elements 60 are arranged along the Y-axis. On the vibrating plate 350, two rows formed by these plurality of piezoelectric elements 60 are formed in the direction along the X-axis. It should be noted that in Figure 10 The simplified diagram illustrates the structure of the piezoelectric element 60.

[0091] Furthermore, a protective substrate 330, approximately the same size as the pressure chamber substrate 310, is bonded to the -Z side of the pressure chamber substrate 310 using an adhesive or the like. The protective substrate 330 has a holding portion 331, which serves as a space for protecting the piezoelectric element 60. Each holding portion 331 is independently provided for each row of piezoelectric elements 60 arranged along the Y-axis. That is, two holding portions 331 are arranged in the X-axis direction. Furthermore, a through hole 332, penetrating the protective substrate 330 in the Z-axis direction, is provided between the two holding portions 331 arranged in the X-axis direction.

[0092] Furthermore, a housing component 340 is fixed on the protective substrate 330. The housing component 340, together with the pressure chamber substrate 310, forms a manifold 400 communicating with a plurality of pressure chambers 312. When viewed from the -Z side, the housing component 340 has a shape substantially the same as the aforementioned connecting plate 315, and is joined to both the protective substrate 330 and the aforementioned connecting plate 315.

[0093] A receiving portion 341 is formed on the protective substrate 330 side of the housing component 340, which is deep enough to accommodate the pressure chamber substrate 310 and the protective substrate 330. The receiving portion 341 has an opening area larger than the surface of the protective substrate 330 that is joined to the pressure chamber substrate 310. Thus, when the pressure chamber substrate 310 and the protective substrate 330 are accommodated in the receiving portion 341, the opening surface of the receiving portion 341 on the nozzle plate 320 side is sealed by the connecting plate 315.

[0094] Furthermore, on the housing component 340, third manifold portions 342 are formed on both outer sides of the receiving portion 341 along the X-axis. These third manifold portions 342, together with the first manifold portion 317 and the second manifold portion 318 provided on the connecting plate 315, constitute a manifold 400. The manifold 400 is continuously arranged along the entire Y-axis, and the supply communication channels 319 connecting the manifold 400 and each pressure chamber 312 are arranged along the Y-axis.

[0095] Furthermore, a supply port 344 is provided on the housing component 340, which communicates with the manifold 400 for supplying ink to the manifold 400. Additionally, a connection port 343 is formed on the housing component 340, which communicates with the through hole 332 of the protective substrate 330, through which the wiring substrate 420 is inserted.

[0096] Ink stored in ink container 2 is drawn into the ejection module 22 configured as described above through supply port 344. Then, after the manifold 400 and nozzle 321 are filled with ink supplied from supply port 344, a drive signal VOUT based on drive signal COM is supplied from integrated circuit 421, including drive signal selection circuit 200, to piezoelectric element 60 corresponding to each of the plurality of pressure chambers 312. This causes the piezoelectric element 60 to deform, resulting in flexural deformation of the vibrating plate 350 of the piezoelectric element 60. As a result, the internal pressure of each pressure chamber 312 increases, and ink is ejected from the corresponding nozzle 321.

[0097] Next, the configuration of the ejection module 22 stacked on the -Z side of the pressure chamber substrate 310 will be described in detail. On the -Z side of the pressure chamber substrate 310 of the ejection module 22, in addition to the vibrating plate 350 and piezoelectric element 60 mentioned above, there are also individual lead electrodes 391, common lead electrodes 392, measurement lead electrodes 393 and resistance wiring 401 stacked.

[0098] like Figures 9-12 As shown, the vibrating plate 350 is configured to include: an elastic film 351, which is made of silicon oxide disposed on the pressure chamber substrate 310 side; and an insulating film 352, which is made of a zirconium oxide film disposed on the -Z side of the elastic film 351. Thus, in the liquid flow channel such as the pressure chamber 312 formed by anisotropic etching of the pressure chamber substrate 310 from the +Z side, the -Z side surface is constituted by the elastic film 351 included in the vibrating plate 350. It should be noted that the configuration of the vibrating plate 350 is not limited to the above configuration. The vibrating plate 350 may be composed of, for example, the elastic film 351 or the insulating film 352, or it may be configured to include other films besides the elastic film 351 and the insulating film 352. Examples of other films included in the vibrating plate 350 include films containing silicon, silicon nitride, etc.

[0099] The piezoelectric element 60 on the -Z side of the vibrating plate 350 includes an electrode 360, a piezoelectric body 370, and an electrode 380 stacked from the +Z side toward the -Z side. That is, the piezoelectric element 60 includes electrodes 360, 380, and a piezoelectric body 370, and the electrodes 360, 370, and 380 are stacked sequentially along the Z-axis.

[0100] Electrodes 360 and 380 are both electrically connected to the wiring substrate 420. Thus, electrodes 360 and 380 supply the piezoelectric element 370 with the drive signal VOUT output from the drive signal selection circuit 200 included in the integrated circuit 421 mounted on the wiring substrate 420 and the reference voltage signal VBS propagating in the wiring substrate 420. Specifically, a drive signal VOUT, whose voltage value varies according to the amount of ink ejected from the nozzle 321, is supplied to electrode 360 ​​of the piezoelectric element 60, while a reference voltage signal VBS, whose voltage value remains constant regardless of the amount of ink ejected, is supplied to electrode 380 of the piezoelectric element 60. This creates a potential difference between electrodes 360 and 380, resulting in deformation of the piezoelectric element 370. In other words, the piezoelectric element 60 is driven. Then, with the drive of the piezoelectric element 60, the vibrating plate 350 deforms or vibrates, and the volume of the pressure chamber 312 changes. This change in the volume of the pressure chamber 312 applies pressure to the ink stored in the pressure chamber 312. As a result, the ink is ejected from the nozzle 321 via the nozzle communication channel 316.

[0101] In the following description, the portion of the piezoelectric element 60 that produces piezoelectric strain when voltage is applied to electrodes 360 and 380 is referred to as the active portion 410, and the portion of the piezoelectric element 370 that does not produce piezoelectric strain is referred to as the inactive portion 415. That is, within the piezoelectric element 60, the portion of the piezoelectric element 370 that is clamped by electrodes 360 and 380 corresponds to the active portion 410, and the portion of the piezoelectric element 370 that is not clamped by electrodes 360 and 380 corresponds to the inactive portion 415. Furthermore, the portion that displaces along the Z-axis when the piezoelectric element 60 is driven is referred to as the flexible portion, and the portion that does not displace along the Z-axis is referred to as the non-flexible portion. That is, within the piezoelectric element 60, the portion opposite the pressure chamber 312 in the Z-axis direction corresponds to the flexible portion, and the outer portion of the pressure chamber 312 corresponds to the non-flexible portion. It should be noted that in the following description, the active part 410 will sometimes be referred to as the active part, and the inactive part 415 as the passive part.

[0102] Therefore, either electrode 360 ​​or 380 located in the active part 410 is configured as an independent individual electrode corresponding to each active part 410, while the other electrode 360 ​​or 380 located in the active part 410 is configured as a common electrode shared by multiple active parts 410. It should be noted that in the following description, electrode 360 ​​is configured as an individual electrode and electrode 380 is configured as a common electrode.

[0103] Specifically, the electrode 360 ​​is disposed on the +Z side of the piezoelectric body 370 along the Z-axis, and is divided corresponding to the pressure chamber 312, forming an independent individual electrode corresponding to each active part 410. That is, an electrode 360 ​​is individually disposed corresponding to each of the plurality of pressure chambers 312. At this time, the width of the electrode 360 ​​along the Y-axis is narrower than the width of the pressure chamber 312 along the Y-axis. That is, in the Y-axis direction, the end of the electrode 360 ​​is located inside the region opposite to the pressure chamber 312.

[0104] Furthermore, the +X side end 360a and the -X side end 360b of the electrode 360 ​​are located outside the pressure chamber 312, respectively. For example, in the first pressure chamber row, such as Figure 11 As shown, end 360a of electrode 360 ​​is located closer to the +X side than end 312a of pressure chamber 312 on the +X side, and end 360b of electrode 360 ​​is located closer to the -X side than end 312b of pressure chamber 312 on the -X side.

[0105] piezoelectric element 370 Figure 9 As shown, the length along the X-axis is set to a predetermined length, and it is continuously arranged along the entire Y-axis. That is, the piezoelectric element 370 is continuously arranged in a parallel arrangement direction along the pressure chamber 312 with a predetermined thickness. The thickness of such piezoelectric element 370 is not particularly limited, and it is formed with a thickness of about 1000 nanometers to 4000 nanometers.

[0106] In addition, such as Figure 11 As shown, the length of the piezoelectric element 370 along the X-axis is longer than the length of the pressure chamber 312 along the X-axis. Therefore, the piezoelectric element 370 is positioned such that it extends to the outside of the pressure chamber 312 on both sides along the X-axis. By extending the piezoelectric element 370 to the outside of the pressure chamber 312 along the X-axis, the strength of the vibrating plate 350 is improved, reducing the risk of abnormalities such as cracks in the vibrating plate 350 and the piezoelectric element 60 when the active part 410 is driven to displace the piezoelectric element 60.

[0107] In addition, such as Figure 11 As shown, for example, the +X side end 370a of the piezoelectric element 370 corresponding to the first pressure chamber row is located further outward, i.e., further towards the +X side, than the end 360a of the electrode 360. That is, the end 360a of the electrode 360 ​​is covered by the piezoelectric element 370. On the other hand, the -X side end 370b of the piezoelectric element 370 corresponding to the first pressure chamber row is located further inward, i.e., further towards the +X side, than the end 360b of the electrode 360. That is, the end 360b of the electrode 360 ​​is not covered by the piezoelectric element 370.

[0108] In addition, such as Figure 9 as well as Figure 12 As shown, grooves 371, which are thinner than other areas, are formed on the piezoelectric body 370 corresponding to each partition wall 311. Here, as... Figure 12 As shown, the groove 371 may also be formed by completely removing the piezoelectric element 370 in the direction along the Z-axis. That is, the portion of the piezoelectric element 370 that is thinner than other regions also includes the case where the piezoelectric element 370 is completely removed in the direction along the Z-axis. Of course, the piezoelectric element 370 on the bottom surface of the groove 371 may also be formed to be thinner than the piezoelectric element 370 in other regions. Furthermore, the length of the groove 371 in the direction along the Y-axis, that is, the width of the groove 371, is the same as or wider than the width of the partition wall 311. When viewed from the -Z side, such a groove 371 is formed into a rectangular shape. It should be noted that the shape of the groove 371 when viewed from the -Z side is not limited to a rectangular shape; it may also be a polygon with a pentagonal or larger shape, or a circular shape, an oval shape, etc.

[0109] By providing the groove 371 to the piezoelectric body 370, the rigidity of the portion of the vibrating plate 350 that faces the end of the pressure chamber 312 along the Y-axis, i.e., the arm of the vibrating plate 350, is suppressed. As a result, the piezoelectric element 60 can be displaced more effectively.

[0110] like Figure 9 , Figure 11 as well as Figure 12 As shown, electrode 380 is disposed on the side opposite to electrode 360, i.e., the -Z side of piezoelectric body 370, relative to piezoelectric body 370, constituting a common electrode shared by multiple active parts 410. That is, electrode 380 is configured to be shared by multiple pressure chambers 312. Electrode 380 is disposed continuously along the entire Y-axis direction with a predetermined length along the X-axis. In addition to being disposed on the inner surface of groove 371, i.e., the side surface of groove 371 of piezoelectric body 370, electrode 380 is also disposed on the insulating film 352, which serves as the bottom surface of groove 371. It should be noted that, regarding the inner surface of groove 371, electrode 380 may be disposed only on a portion of the inner surface of groove 371, or may not cover the entire inner surface of groove 371.

[0111] Furthermore, for example, in the first pressure chamber row, Figure 11As shown, the +X side end 380a of electrode 380 is positioned further outward on the +X side than the end 360a of electrode 360 ​​covered by piezoelectric body 370. That is, the end 380a of electrode 380 is located further outward than the end 312a of pressure chamber 312, i.e., further outward on the +X side, and further outward than the end 360a of electrode 360, i.e., further outward on the +X side. Therefore, the end 380a of electrode 380 substantially coincides with the end 370a of piezoelectric body 370 in the direction along the X-axis. Thus, the end 360a of electrode 360 ​​defines the +X side end of active portion 410, i.e., the boundary between active portion 410 and inactive portion 415.

[0112] On the other hand, the -X side end 380b of electrode 380 is positioned further outward than the end 312b of pressure chamber 312, i.e., further towards the -X side, but further inward than the end 370b of piezoelectric body 370, i.e., further towards the +X side. As described above, the end 370b of piezoelectric body 370 is located further towards the +X side than the end 360b of electrode 360, i.e., further inward. Therefore, the end 380b of electrode 380 is located on piezoelectric body 370 further towards the +X side than the end 360b of electrode 360. Therefore, there is a portion on the -X side of end 380b of electrode 380 that exposes the surface of piezoelectric body 370.

[0113] Thus, the end 380b of electrode 380 is positioned further towards the +X side than the end 370b of piezoelectric body 370 and the end 360b of electrode 360. Therefore, the end 380b of electrode 380 defines the -X side end of active portion 410, that is, the boundary between active portion 410 and inactive portion 415.

[0114] Furthermore, a wiring portion 385 is provided on the outer side of the end 380b of the electrode 380, that is, further towards the -X side than the end 380b of the electrode 380. This wiring portion 385 is on the same layer as the electrode 380, but is not electrically continuous with the electrode 380. Moreover, the wiring portion 385 is formed from the piezoelectric body 370 to the electrode 360, which extends further towards the -X side than the piezoelectric body 370, with intervals between them and without contacting the end 380b of the electrode 380. This wiring portion 385 is provided independently for each active portion 410. That is, a plurality of wiring portions 385 are arranged at predetermined intervals along the Y-axis. It should be noted that the wiring portion 385 may also be formed on a different layer than the electrode 380, but it is preferable to form it on the same layer as the electrode 380. This simplifies the manufacturing process of the wiring portion 385 and reduces costs.

[0115] Furthermore, individual lead electrodes 391 are electrically connected to the electrodes 360 of the piezoelectric element 60, and a common lead electrode 392 serving as a common driving electrode is electrically connected to the electrodes 380 of the piezoelectric element 60. Additionally, a flexible wiring substrate 420 is electrically connected to the ends of the individual lead electrodes 391 and the common lead electrode 392 opposite to the end connected to the piezoelectric element 60. Furthermore, wiring (not shown) is formed on the wiring substrate 420, which is electrically connected to multiple circuits including the control mechanism 10 and the temperature information output circuit 26. Such a wiring substrate 420 is, for example, made of an FPC (Flexible Printed Circuit). It should be noted that the wiring substrate 420 can also be made of any flexible substrate; for example, it can be made of an FFC (Flexible Flat Cable) instead of an FPC.

[0116] Furthermore, the individual lead electrode 391 and the common lead electrode 392 extend outward from the through-hole 332 formed in the protective substrate 330. Thus, they are electrically connected to the wiring substrate 420 inside the through-hole 332. Additionally, an integrated circuit 421 is mounted on the wiring substrate 420, which includes a drive signal selection circuit 200 that outputs a drive signal VOUT for driving the piezoelectric element 60.

[0117] Individual lead electrodes 391 and shared lead electrodes 392 are formed in the same layer, but are not electrically continuous. This simplifies the manufacturing process and reduces costs compared to forming individual lead electrodes 391 and shared lead electrodes 392 separately. Of course, individual lead electrodes 391 and shared lead electrodes 392 can also be formed in different layers. It should be noted that individual lead electrodes 391 and shared lead electrodes 392 can also have a sealing layer that improves adhesion to electrodes 360 and 380, and the vibrating plate 350.

[0118] Individual lead electrodes 391 are provided corresponding to each active part 410, i.e., each electrode 360. For example... Figure 11 As shown, for example, in a pressure chamber array, a single lead electrode 391 is connected via a wiring portion 385 to the vicinity of the end 360b of an electrode 360 ​​disposed on the outside of the piezoelectric body 370, and is led out to the pressure chamber substrate 310 on the -X side, and actually led out to the vibrating plate 350.

[0119] On the other hand, such as Figure 9As shown, for example, in the first pressure chamber array, the common lead electrode 392 extends from the electrode 380 constituting the common electrode on the piezoelectric body 370 towards the -X side at both ends along the Y-axis direction to the vibrating plate 350. Furthermore, the common lead electrode 392 has an extension portion 392a and an extension portion 392b. (As shown...) Figure 9 as well as Figure 11 As shown, for example, in the first pressure chamber row, the extension portion 392a extends along the Y-axis in the region corresponding to the end 312a of the pressure chamber 312, and the extension portion 392b extends along the Y-axis in the region corresponding to the end 312b of the pressure chamber 312. These extension portions 392a and 392b are continuously provided relative to the plurality of active portions 410 in the entire direction along the Y-axis.

[0120] Furthermore, the extension portions 392a and 392b extend from the inside of the pressure chamber 312 to the outside of the pressure chamber 312 in the direction along the X-axis. In this embodiment, the active portion 410 of the piezoelectric element 60 extends to the outside of the pressure chamber 312 at both ends in the direction along the X-axis, and the extension portions 392a and 392b extend from the active portion 410 to the outside of the pressure chamber 312.

[0121] like Figure 11 As shown, a resistance wire 401 is provided on the -Z side surface of the vibrating plate 350. The resistance wire 401 is a configuration for detecting the temperature of the pressure chamber 312 and constitutes at least a part of the temperature detection circuit 24 described above. The temperature detection circuit 24 of this embodiment utilizes the characteristic that the resistance value of metals, semiconductors, etc., changes with temperature. As the material for such a resistance wire 401, any material whose resistance value is temperature-dependent can be used, such as gold (Au), platinum (Pt), iridium (Ir), aluminum (Al), copper (Cu), titanium (Ti), tungsten (W), nickel (Ni), chromium (Cr), etc. Among them, platinum (Pt) has a large resistance value change with temperature, and from the perspective of stability and high accuracy, it is a suitable material for the resistance wire 401. The resistance wire 401 is stacked on the -Z side surface of the vibrating plate 350 in the same layer as the electrode 360 ​​in a manner that is not electrically continuous with the electrode 360.

[0122] like Figure 9As shown, the resistance wiring 401 is a continuous wiring pattern stacked on the vibrating plate 350. One end of the resistance wiring 401 located on the +X side along the X-axis is connected to the measuring lead electrode 393a, and the other end of the resistance wiring 401 located on the -X side along the X-axis 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 via the wiring substrate 420. Therefore, the temperature information output circuit 26 acquires the resistance value of the resistance wiring 401, which varies according to the temperature of the pressure chamber 312, i.e., the voltage across the resistance wiring 401, which varies according to the temperature of the pressure chamber 312, as a signal corresponding to the temperature of the pressure chamber 312.

[0123] Such resistor wiring 401 includes a first pressure chamber row side meandering pattern located on the +X side along the X-axis and a second pressure chamber row side meandering pattern located on the -X side along the X-axis. The first pressure chamber row side meandering pattern is configured such that, when viewed from the -Z side, at least a portion overlaps with the supply communication channel 319 communicating with each pressure chamber 312 constituting the first pressure chamber row, and meanders along the Y-axis. The second pressure chamber row side meandering pattern is configured such that, when viewed from the -Z side, at least a portion overlaps with the supply communication channel 319 communicating with each pressure chamber 312 constituting the second pressure chamber row, and meanders along the Y-axis. That is, the resistor wiring 401 included in the temperature detection circuit 24 includes a first pressure chamber row side meandering pattern corresponding to the first pressure chamber row formed by the plurality of pressure chambers 312 and a second pressure chamber row side meandering pattern corresponding to the second pressure chamber row formed by the plurality of pressure chambers 312. Furthermore, as Figure 10 as well as Figure 11 As shown, the distance between the end of the pressure chamber 312 on the -Z side and the resistor wiring 401 along the Z-axis is shorter than the dimension of the pressure chamber 312 along the Z-axis. Furthermore, in the first pressure chamber row, the longest distance between the end 312a of the pressure chamber 312 and the resistor wiring 401 along the X-axis is shorter than the dimension of the pressure chamber 312 along the X-axis. Therefore, the resistance value of the resistor wiring 401 easily changes in response to temperature variations in the pressure chamber 312.

[0124] The measurement lead electrode 393, including measurement lead electrode 393a and measurement lead electrode 393b, is formed such that it is not electrically continuous with the individual lead electrode 391 and the shared lead electrode 392 in the same layer. Therefore, compared to the case where the measurement lead electrode 393 is formed separately from the individual lead electrode 391 and the shared lead electrode 392, the manufacturing process can be simplified and costs reduced.

[0125] The measuring lead electrode 393 extends and is exposed within a through-hole 332 formed in the protective substrate 330, and is electrically connected to the wiring substrate 420 within the through-hole 332. Thus, the temperature information output circuit 26 can acquire the resistance value of the resistive wiring 401, and the corresponding voltage value, via the wiring substrate 420. Then, in response to a temperature acquisition request signal TD from the control circuit 100, the temperature information output circuit 26 outputs a temperature information signal TI corresponding to temperature information tc, which is information based on the acquired resistance value of the resistive wiring 401, and the corresponding voltage value.

[0126] In the ejection module 22 configured as described above, by stacking the resistive wiring 401 included in the temperature detection circuit 24 within the vibrating plate 350 located inside the ejection module 22, the resistive wiring 401, which serves as the temperature detection circuit 24, can be positioned near the pressure chamber 312. As a result, the deviation between the temperature detected based on the resistance value of the resistive wiring 401 and the temperature of the pressure chamber 312 can be reduced. That is, the detection accuracy of the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 is improved. Consequently, the reliability of the temperature information of the pressure chamber 312 included in the temperature information signal TI output by the temperature information output circuit 26 is improved. Therefore, the accuracy of the control signal Ctrl-H corrected based on the temperature information signal TI is improved, and the accuracy of the control circuit 100 in performing ejection control of the ejection module 22 corresponding to the ink temperature stored in the pressure chamber 312 is improved.

[0127] That is, the printhead 20 of this embodiment has an ejection module 22 comprising: a piezoelectric element 60, which is driven by receiving a drive signal VOUT based on a drive signal COM, and includes electrodes 360, 380, and a piezoelectric body 370, wherein the piezoelectric body 370 is located between electrodes 360 and 380 in the stacking direction of the electrodes 360, 380, and 370, i.e., along the Z-axis; and a vibrating plate 350, which is located on one side (+Z side) of the stacking direction (i.e., along the Z-axis) relative to the piezoelectric element 60, and is driven by the piezoelectric element. The pressure chamber substrate 310 is located on the +Z side of the stacking direction (along the Z-axis) relative to the vibrating plate 350, and is provided with a plurality of pressure chambers 312 whose volume changes due to the deformation of the vibrating plate 350; the nozzle 321 ejects ink in response to the change in volume of the pressure chamber 312; and the resistive wiring 401 is located on the -Z side of the stacking direction (along the Z-axis) relative to the vibrating plate 350, and constitutes at least a part of the temperature detection circuit 24 for detecting the temperature of the pressure chamber 312.

[0128] This reduces the temperature difference between the temperature detected based on the resistance value of the resistive wiring 401 (which functions as the temperature detection circuit 24) and the temperature inside the pressure chamber 312, thereby improving the accuracy of the temperature detection of the pressure chamber 312 detected by the temperature detection circuit 24. As a result, the control circuit 100 can perform ejection control on the ejection module 22 to achieve an ejection temperature suitable for the ink inside the pressure chamber 312.

[0129] Furthermore, by stacking at least a portion of the resistive wiring 401, which serves as the temperature detection circuit 24, onto the vibrating plate 350, the resistive wiring 401, which serves as the temperature detection circuit 24, can be positioned closer to the pressure chamber 312, further improving the detection accuracy of the temperature of the pressure chamber 312 detected by the temperature detection circuit 24. As a result, the control circuit 100 can perform more suitable ejection control of the ejection module 22 for the temperature of the ink within the pressure chamber 312.

[0130] 5. Composition and operation of the temperature information output circuit

[0131] As described above, in the liquid ejection device 1 of this embodiment, a resistance wire 401, which is part of a temperature detection circuit 24 for detecting the temperature of the ejection module 22, is provided on the vibrating plate 350 inside the ejection module 22 of the printhead 20. That is, the resistance wire 401, which is part of the temperature detection circuit 24, is located near the pressure chamber 312 where the ink is stored. This reduces the temperature difference between the temperature detected based on the change in resistance value of the resistance wire 401 and the temperature inside the pressure chamber 312, i.e., the temperature of the ink stored inside the pressure chamber 312, thereby improving the accuracy of the temperature detection of the pressure chamber 312, i.e., the temperature of the ink stored in the pressure chamber 312, as detected by the temperature detection circuit 24.

[0132] On the other hand, since the resistor wiring 401 included in the temperature detection circuit 24 is located near the pressure chamber 312 where the ink is stored, the wiring that propagates the temperature detection signal TC containing the temperature information tc detected by the resistor wiring 401 is located near the wiring that propagates the control signal Ctrl-H and the drive signal COM of the drive ejection module 22. As a result, a new problem arises as described below: the risk of noise caused by the control signal Ctrl-H and the drive signal COM being superimposed on the temperature detection signal TC containing the temperature information tc detected by the resistor wiring 401 is increased, and there is a risk of reduced detection accuracy of the temperature of the pressure chamber 312 detected by the temperature detection circuit 24.

[0133] Furthermore, the ejection module 22 utilizes the deformation or vibration of the vibrating plate 350 caused by the drive of the piezoelectric element 60 to change the volume of the pressure chamber 312, thereby applying pressure to the ink contained in the pressure chamber 312 and ejecting the ink from the nozzle 321. Therefore, due to the pressure change in the pressure chamber 312, the temperature of the ink stored in the pressure chamber 312 changes instantaneously. At this time, since the resistive wiring 401 included in the temperature detection circuit 24 is located near the pressure chamber 312, there is a possibility that the temperature detection circuit 24 may also detect the temperature change caused by the pressure change in the pressure chamber 312. Therefore, assuming that the resistive wiring 401 included in the temperature detection circuit 24 also detects the temperature change caused by the pressure change in the pressure chamber 312, the temperature detection signal TC output by the temperature detection circuit 24 may fluctuate due to a small difference in the timing of acquiring the temperature of the pressure chamber 312. As a result, there is a risk of reduced reliability of the temperature detection signal TC output by the temperature detection circuit 24 and the temperature information signal TI based on the temperature detection signal TC.

[0134] To address this issue, in the liquid ejection device 1 of this embodiment, the temperature information output circuit 26 acquires multiple temperature information tc detected by the temperature detection circuit 24 at different timings and outputs a temperature information signal TI based on the acquired multiple temperature information tc. Then, the control circuit 100 corrects various signals, including the drive signal COM, based on the input temperature information signal TI. That is, the temperature information output circuit 26 outputs a temperature information signal TI corresponding to the acquired multiple temperature information tc, and the drive signal COM is corrected based on the temperature information signal TI output by the temperature information output circuit 26. Therefore, compared to a temperature information signal TI generated based on a single temperature information tc, the reliability of the temperature information signal TI output by the temperature information output circuit 26 is improved. That is, the accuracy of temperature acquisition in the ejection module 22 is improved. Consequently, the correction accuracy of the control signal Ctrl-H in the control circuit 100 based on the temperature information signal TI is improved, and the accuracy of the drive signal COM output by the drive circuit 50 based on the basic drive signal dO included in the control signal Ctrl-H is improved. As a result, the ejection accuracy of the ink ejected from the ejection module 22 is improved.

[0135] In other words, in the liquid ejection device 1 and printhead 20 of this embodiment, the drive signal COM is corrected by multiple temperature information tc corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 at different time intervals. As a result, the ejection accuracy of the ink ejected from the ejection module 22 is improved.

[0136] Here, the specific structure and operation of the temperature information output circuit 26 that performs such an action will be explained. Figure 13 This diagram illustrates the functional configuration of the temperature information output circuit 26. Based on the temperature acquisition request signal TD input from the control circuit 100, the temperature information output circuit 26 acquires the temperature information tc1 to tcn contained in the temperature detection signals TC1 to TCn input from the respective ejection modules 22-1 to 22-n, and generates a temperature information signal TI corresponding to the acquired temperature information tc1 to tcn, which is then output to the control circuit 100.

[0137] like Figure 13 As shown, the temperature information output circuit 26 includes a control circuit 500, amplifier circuits 510-1 to 510-n, a multiplexer 530, an AD conversion circuit 540, and a storage circuit 550.

[0138] The corresponding temperature detection signals TC1 to TCn are each input to amplifier circuits 510-1 to 510-n. Then, amplifier circuits 510-1 to 510-n amplify the input temperature detection signals TC1 to TCn and output them as amplified detection signals ATC1 to ATCn.

[0139] Specifically, the temperature detection signal TC1 output by the ejection module 22-1 is input to the amplifier circuit 510-1. The amplifier circuit 510-1 amplifies the input temperature detection signal TC1 and outputs it as the amplified detection signal ATC1. Furthermore, the temperature detection signal TCp output by the ejection module 22-p is input to the amplifier circuit 510-p (p is any one from 1 to n). Then, the amplifier circuit 510-p amplifies the input temperature detection signal TCp and outputs it as the amplified detection signal ATCp.

[0140] The amplified detection signals ATC1 to ATCn output by amplifier circuits 510-1 to 510-n are input to multiplexer 530. Furthermore, a selection signal Sel output by control circuit 500 is input to multiplexer 530. Multiplexer 530 selects any one of the amplified detection signals ATC1 to ATCn according to the input selection signal Sel, and outputs it as the selected temperature signal STC.

[0141] The selected temperature signal STC output by the multiplexer 530 is input to the AD conversion circuit 540. The AD conversion circuit 540 acquires the input selected temperature signal STC at a predetermined sampling period and successively converts it into a digital signal for output to the control circuit 500. That is, the AD conversion circuit 540 acquires the temperature information tc contained in the temperature detection signals TC selected by the multiplexer 530 from the temperature detection signals TC1 to TCn of the input temperature information output circuit 26 at each predetermined sampling period and converts it into a digital signal. Then, the AD conversion circuit 540 converts the information corresponding to the acquired temperature information tc into a digital signal and outputs it to the control circuit 500. In other words, the AD conversion circuit 540 successively acquires the information corresponding to the temperature of the ejector module 22 corresponding to the temperature detection signal TC selected by the multiplexer 530 and successively outputs the digital signal corresponding to the acquired temperature to the control circuit 500. In the following description, the digital signal output by the AD conversion circuit 540 is referred to as the digital temperature information dtc.

[0142] The temperature acquisition request signal TD, the latch signal LAT specifying the ink ejection period tp from the ejection module 22, and the digital temperature information dtc output by the AD conversion circuit 540 are input to the control circuit 500. Then, the control circuit 500 controls the operation of various circuits in the temperature information output circuit 26 according to the input temperature acquisition request signal TD. As a result, the temperature information output circuit 26 generates and outputs a temperature information signal TI corresponding to the input temperature acquisition request signal TD.

[0143] Specifically, the control circuit 500 specifies the ejector module 22 to acquire temperature by parsing the input temperature acquisition request signal TD. Then, at a timing specified by the latch signal LAT, the control circuit 500 outputs a selection signal Sel for selecting the temperature detection signal TC corresponding to the ejector module 22 corresponding to the parsing result of the temperature acquisition request signal TD. Thus, the digital temperature information dtc corresponding to the temperature information tc contained in the temperature detection signal TC corresponding to the ejector module 22 specified based on the temperature acquisition request signal TD is successively input to the control circuit 500 according to the sampling period of the AD conversion circuit 540.

[0144] At this time, the control circuit 500 outputs a memory control signal MA to store the input digital temperature information dtc in the storage circuit 550. Thus, the digital temperature information dtc, input sequentially according to the sampling period of the AD conversion circuit 540, is sequentially stored in the storage circuit 550. Such a storage circuit 550 can be configured, for example, to include a register, a memory, etc.

[0145] Furthermore, after acquiring the digital temperature information dtc, the control circuit 500 outputs a memory control signal MA for reading the digital temperature information dtc stored in the storage circuit 550. Consequently, a memory read signal MR, including multiple digital temperature information dtcs output by the AD conversion circuit 540 during a predetermined period, is input to the control circuit 500. That is, the control circuit 500 acquires multiple digital temperature information dtcs output by the AD conversion circuit 540 during a predetermined period. Then, the control circuit 500 generates and outputs a temperature information signal TI based on the acquired multiple digital temperature information dtcs. That is, the control circuit 500 outputs a temperature information signal TI corresponding to the temperature of the ejection module 22 specified according to the parsing result of the temperature acquisition request signal TD.

[0146] A specific example of the method for acquiring temperature information tc by the temperature information output circuit 26 configured as described above, and the method for generating temperature information signal TI based on the acquired temperature information tc, will be explained. Figure 14 This is a diagram illustrating an example of the timing for the temperature information output circuit 26 to acquire temperature information tc.

[0147] like Figure 14 As shown, within the multiple cycles tp included in the ink ejection cycle from the ejection module 22, and within the cycle tp(q) of any timing cycle tp, a temperature acquisition request signal TD is input to the temperature information output circuit 26. The control circuit 500 of the temperature information output circuit 26 analyzes the input temperature acquisition request signal TD to specify the ejection module 22 that should acquire the temperature requested by the temperature acquisition request signal TD.

[0148] Subsequently, within the multiple cycles tp included in the ink ejection cycle from the ejection module 22, in the cycle tp(q+1) following cycle tp(q), the control circuit 500 outputs a selection signal Sel corresponding to the ejection module 22 whose temperature should be acquired. As a result, the multiplexer 530 selects the amplified detection signal ATC, which is an amplified version of the temperature detection signal TC corresponding to the ejection module 22 whose temperature is requested. Consequently, the amplified detection signal ATC corresponding to the ejection module 22 whose temperature is requested is input to the AD conversion circuit 540.

[0149] The AD conversion circuit 540 sequentially acquires the amplified detection signal ATC input in the period tp(q+1) based on a predetermined sampling period. That is, the AD conversion circuit 540 acquires, at different timings corresponding to the predetermined sampling period, the amplified detection signal ATC obtained by amplifying the temperature detection signal TC corresponding to the temperature of the ejection module 22 to be acquired, i.e., multiple pieces of information tc contained in the temperature detection signal TC corresponding to the temperature of the ejection module 22 to be acquired. Therefore, the AD conversion circuit 540 sequentially outputs multiple digital temperature information dtc corresponding to the multiple pieces of information tc amplified to the control circuit 500.

[0150] That is, the different timings of the digital temperature information dtc obtained by the temperature information tc detected by the temperature detection circuit 24 are contained in the period tp(q+1). The period tp(q+1) is the period during which the ejection module 22 receives the drive signal COM and ejects ink, and is the period from the time the latch signal LAT is input to the ejection module 22 until the next input of the latch signal LAT.

[0151] Then, within the ink ejection cycle from the ejection module 22, specifically in the period tp(q+2) following period tp(q+1), the control circuit 500 generates a temperature information signal TI based on multiple digital temperature information dtcs and outputs it to the control circuit 100. That is, the control circuit 500 generates the temperature information signal TI based on multiple digital temperature information dtcs corresponding to the temperature of the ejection module 22 specified by the temperature acquisition request signal TD, and outputs it to the control circuit 100.

[0152] Subsequently, the control circuit 100 calculates the correction value of the control signal Ctrl-H based on the input temperature information signal TI. Within the ink ejection cycle tp from the ejection module 22, specifically in the period tp(q+3) following period tp(q+2), it outputs the corrected control signal Ctrl-H based on the calculated correction value. Consequently, the drive circuit 50 outputs the corrected drive signal COM based on the temperature information signal TI within period tp(q+3).

[0153] As described above, in the liquid ejection device 1 and the print head 20 of this embodiment, the corrected drive signal COM input to the print head 20 is corrected based on multiple temperature information tc corresponding to the temperature of the pressure chamber 312 detected at different timings by the resistor wiring 401 included in the temperature detection circuit 24.

[0154] Specifically, a latch signal LAT is input to the printhead 20, specifying the ink ejection cycle, i.e., cycle tp, from the ejection module 22. Then, the temperature information output circuit 26 of the ejection module 22, within a plurality of cycles tp(q+1) from the time the ejection module 22 receives the drive signal COM and ejects ink (i.e., after inputting the latch signal LAT until the next input of the latch signal LAT), successively acquires information corresponding to the temperature information tc detected by the resistive wiring 401 included in the temperature detection circuit 24 at different timings based on the sampling period. Afterwards, the temperature information output circuit 26 outputs a temperature information signal TI corresponding to the plurality of temperature information tc acquired in cycle tp(q+1) to the control circuit 100. Thus, the drive signal COM input to the ejection module 22 is corrected based on the temperature information signal TI.

[0155] Next, an example of a method for generating a temperature information signal TI based on the acquired digital temperature information dtc corresponding to the temperature information tc contained in the temperature detection signal TC will be described.

[0156] Figure 15 This is a diagram illustrating an example of how the temperature information output circuit 26 generates the temperature information signal TI.

[0157] like Figure 15 As shown, when the temperature information output circuit 26 generates the temperature information signal TI, the temperature information output circuit 26 initializes the temperature acquisition count N, the variable j, and the total value Tsum. Specifically, the control circuit 500 included in the temperature information output circuit 26 initializes the temperature acquisition count N to "0", the variable j to "1", and the total value Tsum to "0" (step S110). Afterwards, a temperature acquisition request signal TD requesting the temperature of the ejection module 22-p is input to the temperature information output circuit 26 (step S120). The control circuit 500 specifies the ejection module 22-p to acquire the temperature by parsing the input temperature acquisition request signal TD.

[0158] Subsequently, by inputting a latch signal LAT to the temperature information output circuit 26 (step S130), the control circuit 500 outputs a selection signal Sel (step S140) to select the temperature detection signal TCp corresponding to the ejection module 22-p specified according to the parsing result of the temperature acquisition request signal TD. Thus, the multiplexer 530 included in the temperature information output circuit 26 selects the amplified detection signal ATCp after the temperature detection signal TCp is amplified by the amplification circuit 510-p, and outputs it to the AD conversion circuit 540.

[0159] After the multiplexer 530 outputs the selected amplified detection signal ATCp to the AD conversion circuit 540, the temperature information output circuit 26 performs temperature information acquisition processing (step S150) to acquire the digital temperature information dtc output by the AD conversion circuit 540 at each predetermined sampling period and store it in the storage circuit 550.

[0160] Specifically, in the temperature information acquisition process (step S150), the AD conversion circuit 540 converts the amplified detection signal ATCp input from the multiplexer 530 into digital temperature information dtc and outputs it to the control circuit 500. The control circuit 500 acquires the digital temperature information dtc output by the AD conversion circuit 540 (step S151), stores the acquired digital temperature information dtc in the storage circuit 550 (step S152), and increments the temperature acquisition count N by "1" (step S153). Afterwards, the control circuit 500 determines whether the latch signal LAT is input to the temperature information output circuit 26 (step S154). If the latch signal LAT is not input to the temperature information output circuit 26 ("No" in step S154), the control circuit 500 repeats the above steps S151 to S153. Then, the temperature information output circuit 26 is input via the latch signal LAT ("Yes" in step S154), and the control circuit 500 ends the temperature information acquisition process (step S150).

[0161] That is, during the period tp from the input latch signal LAT to the next input latch signal LAT, the temperature information output circuit 26 acquires N digital temperature information dtc corresponding to the N temperature information tcp contained in the temperature detection signal TCp, and stores them sequentially in the storage circuit 550.

[0162] After the temperature information acquisition process (step S150) is completed, the control circuit 500 reads the digital temperature information dtc contained in the storage circuit 550, specifically, the N digital temperature information dtcs acquired in the temperature information acquisition process (step S150) (step S160). Then, the control circuit 500 performs temperature information output processing (step S170) to calculate and output the temperature information signal TI based on the read N digital temperature information dtcs.

[0163] In this embodiment, the temperature information output circuit 26, during temperature information output processing (step S170), excludes a portion of the N digital temperature information dtcs with large deviations, and calculates the average value of the remaining digital temperature information dtcs to generate a temperature information signal TI. That is, the temperature information output circuit 26 calculates the adjusted average value of the N digital temperature information dtcs and outputs it as the temperature information signal TI.

[0164] Specifically, in the temperature information output processing (step S170), the control circuit 500 calculates the difference ΔT between the temperature shown by the digital temperature information dtc containing the j-th highest temperature among the N digital temperature information dtc read from the storage circuit 550 and the temperature shown by the digital temperature information dtc containing the (N+1-j)-th highest temperature (step S171). At this time, since variable j is "1", the control circuit 500 calculates the difference ΔT between the temperature shown by the digital temperature information dtc containing the first highest temperature among the N digital temperature information dtc read from the storage circuit 550 and the temperature shown by the digital temperature information dtc containing the N-th highest temperature. In other words, when variable j is "1", the control circuit 500 calculates the difference ΔT between the temperature shown by the digital temperature information dtc containing the highest temperature among the N digital temperature information dtc read from the storage circuit 550 and the temperature shown by the digital temperature information dtc containing the lowest temperature. Then, the control circuit 500 determines whether the calculated difference ΔT is greater than the predetermined threshold Tth (step S172).

[0165] If the calculated difference ΔT is greater than the predetermined threshold Tth ("Yes" in step S172), the control circuit 500 increments the variable j by "1" (step S173) and executes the aforementioned steps S171 and S172. That is, since variable j is "2", the control circuit 500 again calculates the difference ΔT between the temperature shown by the digital temperature information dtc containing the second highest temperature information among the N digital temperature information dtc read from the storage circuit 550 and the temperature shown by the digital temperature information dtc containing the (N-1)th highest temperature information (step S171). In other words, when variable j is "2", the control circuit 500 calculates the difference ΔT between the temperature shown by the digital temperature information dtc containing the second highest temperature information among the N digital temperature information dtc read from the storage circuit 550 and the temperature shown by the digital temperature information dtc containing the second lowest temperature information. Then, the control circuit 500 determines whether the calculated difference ΔT is greater than the predetermined threshold Tth (step S172).

[0166] That is, the control circuit 500 performs addition calculations on variable j successively until the difference ΔT between the temperature shown by the digital temperature information dtc containing the j-th highest temperature information among the N digital temperature information dtc read from the storage circuit 550 and the temperature shown by the digital temperature information dtc containing the (N+1-j)-th highest temperature information becomes below a predetermined threshold Tth. In other words, the control circuit 500 searches for the boundary where the difference ΔT between the temperature shown by the digital temperature information dtc containing the j-th highest temperature information and the temperature shown by the digital temperature information dtc containing the j-th lowest temperature information among the N digital temperature information dtc read from the storage circuit 550 becomes less than the predetermined threshold Tth. Then, when the calculated difference ΔT becomes below the predetermined threshold Tth (No in step S172), the control circuit 500 maintains the variable j at this time as the boundary value Bv (step S174).

[0167] After holding variable j as the boundary value Bv, the control circuit 500 holds the temperature shown by the digital temperature information dtc, which includes the highest temperature of the j-th temperature among the N digital temperature information dtc, as the detected temperature information Rdtc (step S175), and adds the detected temperature information Rdtc to the total value Tsum to hold as the new total value Tsum (step S176). Then, the control circuit 500 determines whether variable j is a value obtained by subtracting the boundary value Bv from the value obtained by adding "1" to the temperature acquisition count N (step S177). Then, if the variable j is less than or equal to the value obtained by subtracting the boundary value Bv from the value obtained by adding "1" to the temperature acquisition count N ("Yes" in step S177), the control circuit 500 adds "1" to the variable j, and uses the added variable j to keep the temperature shown by the digital temperature information dtc, which includes the information of the j-th highest temperature, as the detection temperature information Rdtc within the N digital temperature information dtc (step S175), and adds the detection temperature information Rdtc to the total value Tsum to keep it as the new total value Tsum (step S176).

[0168] That is, the control circuit 500 performs an addition operation on the temperatures shown by each digital temperature information dtc up to the digital temperature information dtc showing the temperature up to the temperature up to the (N+1)-Bv, and stores the sum as a total value Tsum. In other words, the control circuit 500 calculates the sum of N-2×(Bv-1) digital temperature information dtcs that represent temperatures lower than the temperature shown by the digital temperature information dtc showing the temperature up to ...

[0169] Then, when variable j exceeds the value obtained by subtracting the boundary value Bv from the value obtained by adding "1" to the temperature acquisition count N (No in step S177), the control circuit 500 calculates the number of digital temperature information dtc added during the calculation of the total value Tsum, i.e., "N-2×(Bv-1)" divided by the calculated total value Tsum, to obtain the average temperature information Tave (step S179). That is, the control circuit 500 calculates the average value of the temperatures shown by the digital temperature information dtc, which includes the temperature information with the highest value Bv, up to the digital temperature information dtc, which includes the temperature information with the highest value N+1-Bv, and obtains it as the average temperature information Tave. In other words, the control circuit 500 calculates the arithmetic mean of N-2×(Bv-1) digital temperature information dtc, which represents the temperature of the digital temperature information dtc including the temperature of the highest Bv and the temperature of the digital temperature information dtc including the temperature of the lowest Bv, and obtains it as the average temperature information Tave.

[0170] Then, the control circuit 500 generates a temperature information signal TI that includes the acquired average temperature information Tave. Then, the temperature information output circuit 26 outputs a temperature information signal TI corresponding to the calculated average temperature information Tave (step S180). In other words, the control circuit 500 outputs the temperature information signal TI, which includes the average temperature information Tave calculated based on the temperature information tcp representing the temperature of the ejection module 22-p, to the control circuit 100. Thus, the temperature information signal output processing of the temperature information output circuit 26 (step S170) and the generation of the temperature information signal TI by the temperature information output circuit 26 are completed.

[0171] As described above, within N digital temperature information dtc, the temperature specified by the j-th digital temperature information dtc (from high to low) and the temperature specified by the (N+1-j)-th digital temperature information dtc (from high to low) of the pressure chamber 312 specified by the digital temperature information dtc are greater than a predetermined threshold Tth, and the temperature specified by the (J+1)-th digital temperature information dtc (from high to low) of the pressure chamber 312 specified by the digital temperature information dtc within N digital temperature information dtc are greater than the temperature specified by the (N+1-j)-th digital temperature information dtc (from high to low) of the pressure chamber 312 specified by the digital temperature information dtc are greater than the temperature specified by the (N+1-j)-th digital temperature information dtc (from high to low) of the pressure chamber 312 specified by the digital temperature information dtc are greater than the temperature specified by the (N+1-j)-th digital temperature information dtc (from high to low) of the pressure chamber 312 specified by the digital temperature information dtc. When the temperature difference ΔT between the Njth digital temperature information dtc (from high to low) is below a predetermined threshold Tth, the temperature information output circuit 26 of this embodiment calculates the arithmetic mean of N-2×j digital temperature information dtcs that are lower than the temperature specified by the jth digital temperature information dtc (from high to low) and higher than the temperature specified by the (N+1-j)th digital temperature information dtc (from high to low) of the pressure chamber 312, and outputs it as the temperature information signal TI.

[0172] Here, the drive circuit 50 is an example of a drive signal output circuit, and the drive signal COM output by the drive circuit 50 is an example of a drive signal. Furthermore, since the drive signal VOUT supplied to the piezoelectric element 60 is generated based on the signal waveform included in the drive signal COM, the drive signal VOUT is also an example of a drive signal. Additionally, the control circuit 100, which corrects and outputs the base drive signal dO based on the temperature information signal TI, is an example of a correction unit. The latch signal LAT, output by the control circuit 100 and defining the ink ejection cycle from the ejection module 22 and the printhead 20, is an example of an ejection cycle defining signal. The multiple cycles tp defined by the latch signal LAT are an example of an ejection cycle, and within the multiple cycles tp, the cycle tp(q+1) is an example of the ejection period and the period of ejected liquid. Furthermore, the electrode 360 ​​included in the ejection module 22 is an example of a first electrode, the electrode 380 included in the ejection module 22 is an example of a second electrode, and at least one of the resistor wiring 401 included in the ejection module 22 and the temperature detection circuit 24 including the resistor wiring 401 is an example of a temperature detection unit.

[0173] Furthermore, at least one of the temperature information tc contained in the temperature detection signal TC output by the temperature detection circuit 24 and the digital temperature information dtc after amplifying and converting the temperature information tc into a digital signal is an example of temperature information. At least one of the multiple temperature information tc and multiple digital temperature information dtc acquired by the temperature information output circuit 26 in the period tp(q+1) is an example of N temperature information. The multiple temperature information tc and multiple digital temperature information dtc acquired by the temperature information output circuit 26 in the period tp(q+1) are arranged in descending order of temperature from high to low by the temperature information tc and digital temperature information dtc. A temperature information tc and a digital temperature information dtc are examples of the i-th temperature information. The Bv-th temperature information tc and the digital temperature information dtc, with temperatures ranging from high to low, are examples of the (i+1)-th temperature information. The Bv-1-th temperature information tc and the digital temperature information dtc, with temperatures ranging from low to high, are examples of the (N+1-i)-th temperature information. The Bv-th temperature information tc and the digital temperature information dtc, with temperatures ranging from low to high, are examples of the Ni-th temperature information.

[0174] 6. Effects

[0175] As described above, in the liquid ejection device 1 and printhead 20 of this embodiment, the ejection module 22 includes: a piezoelectric element 60, which is driven by receiving a drive signal VOUT based on a drive signal COM, and includes an electrode 360, an electrode 380, and a piezoelectric body 370, wherein the piezoelectric body 370 is located between the electrode 360 ​​and the electrode 380 in the stacking direction of the electrode 360, the electrode 380, and the piezoelectric body 370, i.e., along the Z-axis; and a vibrating plate 350, which is located relative to the piezoelectric element 60 in the stack. On one side of the direction, deformation is generated by driving the piezoelectric element 60; the pressure chamber substrate 310 is located on one side of the stacking direction relative to the vibrating plate 350, and is provided with a pressure chamber 312 whose volume changes due to the deformation of the vibrating plate 350; the nozzle 321 ejects ink in response to the change in volume of the pressure chamber 312; and the temperature detection circuit 24 includes a resistor wiring 401 located on the other side of the stacking direction relative to the vibrating plate 350, which detects the temperature of the pressure chamber 312. That is, in the ejection module 22 of this embodiment, the temperature detection circuit 24, which detects the temperature of the ink stored in the pressure chamber 312, is arranged near the pressure chamber 312. As a result, the temperature detection circuit 24 improves the detection accuracy of the temperature of the ink stored in the pressure chamber 312.

[0176] Furthermore, in the liquid ejection device 1 and printhead 20 of this embodiment, the drive signals COM and VOUT that eject ink from the ejection module 22 are corrected based on N temperature information tc and N digital temperature information dtc (N being a natural number greater than 2) corresponding to the temperature of the pressure chamber 312 detected by the temperature detection circuit 24 at different timings. Therefore, compared to the case where the temperature of the pressure chamber 312 is calculated based on a single temperature information tc and digital temperature information dtc, the influence of noise superimposed on the temperature information tc and digital temperature information dtc is reduced. As a result, the correction accuracy of the drive signals COM and VOUT corrected based on the temperature information tc and digital temperature information dtc is improved, and the ejection accuracy of the ink ejected from the ejection module 22 is improved.

[0177] Furthermore, in the liquid ejection device 1 and printhead 20 of this embodiment, since the influence of noise superimposed on the temperature information tc and digital temperature information dtc is reduced, even if the temperature information tc and digital temperature information dtc obtained during the period when the printhead 20 receives the drive signal COM and ejects ink, for example, during the period tp from the input latch signal LAT to the next input latch signal LAT, the risk of a decrease in the correction accuracy of the corrected drive signals COM and VOUT can be reduced. As a result, the ejection accuracy of the ink ejected from the ejection module 22 is improved.

[0178] Furthermore, in the liquid ejection device 1 and printhead 20 of this embodiment, the temperature information output circuit 26 calculates the adjusted average value of N temperature information tc and N digital temperature information dtc, and the drive circuit 50 outputs a drive signal COM that has been corrected based on the temperature information signal TI corresponding to the calculation result. Specifically, the temperature specified by the j-th digital temperature information dtc within the N digital temperature information dtc, from high to low, and the temperature specified by the (N+1)-j-th digital temperature information dtc within the N digital temperature information dtc, from high to low, are greater than a predetermined threshold Tth, and the temperature specified by the (N+1)-th digital temperature information dtc within the N digital temperature information dtc, from high to low, is greater than the temperature specified by the (N+1)-th digital temperature information dtc within the N digital temperature information dtc, from high to low, and the temperature specified by the (N+1)-th digital temperature information dtc within the N digital temperature information dtc, from high to low, and the temperature specified by the (N+1)-th digital temperature information dtc within the N digital temperature information dtc, are greater than ..., from high to low, are greater than the temperature specified by the (N+1)-th digital temperature information dtc within the N digital temperature information dtc, and the temperature specified by the (N+1)-th digital temperature information dtc, from high to low, are greater than the temperature specified by the (N+1)- When the temperature difference ΔT between the Njth digital temperature information dtc (temperature from high to low) and the temperature of the pressure chamber 312 (temperature from high to low) is below a predetermined threshold Tth, the temperature information output circuit 26 calculates the arithmetic mean of the N-2×j digital temperature information dtcs that are lower than the temperature specified by the jth digital temperature information dtc (temperature from high to low) and higher than the temperature specified by the (N+1-j)th digital temperature information dtc (temperature from high to low) of the pressure chamber 312 (temperature from high to low), and outputs it as the temperature information signal TI.

[0179] This eliminates outliers caused by noise and other factors contained in the N digital temperature information dtc, further reducing the impact of noise superimposed on the temperature information tc and the digital temperature information dtc. As a result, the correction accuracy of the drive signals COM and VOUT, corrected based on the temperature information tc and the digital temperature information dtc, is further improved, and the ink ejection accuracy from the ejection module 22 is further improved.

[0180] 7. Variations

[0181] In the liquid ejection device 1 and printhead 20 of this embodiment described above, the following situation was explained: The temperature information output circuit 26 calculates the adjusted average value of N temperature information tc and N digital temperature information dtc, and the drive circuit 50 outputs a drive signal COM corrected based on the temperature information signal TI corresponding to the calculation result. However, the temperature information output circuit 26 can also add all N temperature information tc and N digital temperature information dtc together and use the sum divided by N to obtain the arithmetic mean. That is, the temperature information output circuit 26 can also calculate the arithmetic mean of N temperature information tc and N digital temperature information dtc and output it as the temperature information signal TI. Therefore, the influence of noise superimposed on the temperature information tc and digital temperature information dtc can be reduced through simple calculation. In addition to the effects described above, the computational load of the temperature information output circuit 26 can be reduced.

[0182] The embodiments and variations have been described above, but the present invention is not limited to these embodiments and can be implemented in various ways without departing from its spirit. For example, the above embodiments can also be appropriately combined.

[0183] This invention includes configurations that are substantially the same as those described in the embodiments (e.g., configurations with the same function, method, and result, or configurations with the same purpose and effect). Furthermore, this invention includes configurations that replace non-essential parts of the configurations described in the embodiments. Additionally, this invention includes configurations capable of achieving the same effects as those described in the embodiments or capable of achieving the same purpose. Furthermore, this invention includes configurations incorporating known techniques into the configurations described in the embodiments.

[0184] The following content is derived from the above implementation method.

[0185] One side of the printhead includes an ejection module that ejects liquid upon receiving a corrected drive signal. The ejection module comprises: a piezoelectric element that receives the drive signal and is driven, and includes a first electrode, a second electrode, and a piezoelectric body, wherein the piezoelectric body is located 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; a vibrating plate located on one side of the stacking direction relative to the piezoelectric element, which deforms upon being driven by the piezoelectric element; a pressure chamber substrate located on one side of the stacking direction relative to the vibrating plate, and having a pressure chamber whose volume changes due to the deformation of the vibrating plate; a nozzle that ejects liquid in response to the change in the volume of the pressure chamber; and a temperature detection unit located on the other side of the stacking direction relative to the vibrating plate, which detects the temperature of the pressure chamber. The drive signal is corrected based on N temperature information (N being a natural number greater than 2) corresponding to the temperatures of the pressure chamber detected by the temperature detection unit at different timings.

[0186] According to this printhead, the temperature detection unit for detecting the temperature of the pressure chamber is located inside the ejection module on the opposite side of the stacking direction relative to the vibrating plate, thus enabling the temperature detection unit to be positioned near the pressure chamber on the side of the pressure chamber opposite to the vibrating plate in the stacking direction. This improves the accuracy of the temperature detection unit in detecting the temperature of the pressure chamber.

[0187] Furthermore, according to this printhead, the drive signal for ejecting liquid from the ejection module is corrected based on N temperature information (N being a natural number greater than 2) corresponding to the temperature of the pressure chamber detected by the temperature detection unit at different timings. Therefore, even when noise is superimposed on the temperature information corresponding to the temperature of the pressure chamber detected by the temperature detection unit, the influence of this noise can be reduced. As a result, the correction accuracy of the drive signal, which is corrected based on the temperature of the pressure chamber, is improved. Consequently, the ejection accuracy of the ink ejected from the ejection module based on the corrected drive signal is improved.

[0188] In one aspect of the above-described printhead, an ejection cycle specification signal defining the ejection cycle of the liquid from the ejection module may be input to the printhead, wherein the different timing is included in the ejection period from the input of the ejection cycle specification signal to the next input of the ejection cycle specification signal.

[0189] According to this printhead, even when noise is superimposed on temperature information corresponding to the temperature of the pressure chamber detected by the temperature detection unit, the impact of the noise can be reduced. Therefore, even when temperature information for correcting the drive signal is obtained during the ejection period from the input of the ejection cycle specification signal to the next input of the ejection cycle specification signal, the risk of a decrease in the correction accuracy of the drive signal corrected according to the temperature of the pressure chamber can be reduced. As a result, the ejection accuracy of the ink ejected from the ejection module based on the corrected drive signal is improved.

[0190] In one aspect of the above-described printhead, the printhead may also include a temperature information output circuit that outputs a temperature information signal representing the temperature of the ejection module, the temperature information output circuit outputting a temperature information signal corresponding to the N temperature information acquired during the ejection, and the drive signal being corrected based on the temperature information signal.

[0191] In one aspect of the above-mentioned printhead, the temperature information output circuit may calculate the arithmetic mean of the N temperature information and output it as the temperature information signal.

[0192] This printhead calculates the arithmetic mean of N temperature data points, thereby reducing the impact of noise even when it is superimposed on any one of the N temperature data points corresponding to the temperature of the pressure chamber detected by the temperature detection unit. As a result, the correction accuracy of the drive signal, which is corrected based on the temperature of the pressure chamber, is improved. Therefore, the ink ejection accuracy from the ejection module based on the corrected drive signal is improved.

[0193] In one aspect of the above-mentioned printhead, the temperature information output circuit may calculate the adjusted average value of the N temperature information and output it as the temperature information signal.

[0194] This printhead calculates an adjusted average of N temperature data points, thereby reducing the impact of any outliers caused by noise or other factors, even if any of the N temperature data points corresponding to the temperature of the pressure chamber detected by the temperature detection unit contains such outliers. As a result, the correction accuracy of the drive signal, which is corrected based on the pressure chamber temperature, is improved. Consequently, the ink ejection accuracy from the ejection module based on the corrected drive signal is improved.

[0195] In one aspect of the above-described printhead, it is also possible that: within the N temperature information, the difference between the i-th temperature information (where i is any natural number from 1 to N / 2) and the N+1-i-th temperature information (where N+1-i) is greater than a predetermined threshold, and the difference between the i+1-th temperature information and the Ni-th temperature information (where Ni) is less than the predetermined threshold, the temperature information output circuit calculates the arithmetic mean of the N-2×i temperature information where the temperature of the pressure chamber is lower than the i-th temperature information and higher than the N+1-i-th temperature information, and outputs it as the temperature information signal.

[0196] In one aspect of the above-described printhead, the different timing may also be included during the period when the ejection module receives the drive signal and ejects liquid.

[0197] According to this printhead, even when noise is superimposed on temperature information corresponding to the temperature of the pressure chamber detected by the temperature detection unit, the impact of the noise can be reduced. Therefore, even when temperature information for correcting the drive signal is input during the liquid ejection process of the ejection module, the risk of a decrease in the correction accuracy of the drive signal corrected according to the temperature of the pressure chamber can be reduced. As a result, the ejection accuracy of the ink ejected from the ejection module based on the corrected drive signal is improved.

[0198] One aspect of the liquid ejection device includes: a drive signal output circuit that outputs a calibrated drive signal; a calibration unit that calibrates the drive signal; and a printhead that receives the drive signal and ejects liquid. The printhead has an ejection module that receives the drive signal and ejects liquid. The ejection module includes: a piezoelectric element that receives the drive signal and is driven, and includes a first electrode, a second electrode, and a piezoelectric body, wherein the piezoelectric body is located between the first electrode and the second electrode in the stacking direction of the first electrode, the second electrode, and the piezoelectric body; and a vibrating plate positioned relative to the piezoelectric element. On one side of the stacking direction, deformation is generated by driving the piezoelectric element; a pressure chamber substrate is located on one side of the stacking direction relative to the vibrating plate, and a pressure chamber with a volume change due to the deformation of the vibrating plate is provided; a nozzle ejects liquid in response to the volume change of the pressure chamber; and a temperature detection unit is located on the other side of the stacking direction relative to the vibrating plate, which detects the temperature of the pressure chamber, and the correction unit corrects the driving signal based on N temperature information (N is a natural number of 2 or more) corresponding to the temperature of the pressure chamber detected by the temperature detection unit at different timings.

[0199] According to this liquid ejection device, the temperature detection unit, which detects the temperature of the pressure chamber of the printhead, is located inside the ejection module on the opposite side of the stacking direction relative to the vibrating plate. This allows the temperature detection unit to be positioned near the pressure chamber on the side of the pressure chamber opposite to the vibrating plate in the stacking direction. Consequently, the accuracy of the temperature detection unit in detecting the temperature of the pressure chamber is improved.

[0200] Furthermore, according to this liquid ejection device, the correction unit corrects the drive signal of the ejection module of the printhead to eject liquid based on N temperature information (N being a natural number greater than 2) corresponding to the temperature of the pressure chamber detected by the temperature detection unit at different timings. Therefore, even when noise is superimposed on the temperature information corresponding to the temperature of the pressure chamber detected by the temperature detection unit, the influence of this noise can be reduced, resulting in improved correction accuracy of the drive signal corrected according to the temperature of the pressure chamber. Consequently, the ejection accuracy of the ink ejected from the ejection module based on the corrected drive signal is improved.

Claims

1. A printhead, characterized by, It includes a spraying module and a temperature information output circuit. The spraying module receives a corrected drive signal and sprays liquid, while the temperature information output circuit outputs a temperature information signal representing the temperature of the spraying module. The ejection module has: A piezoelectric element is driven by receiving the corrected driving signal and includes a first electrode, a second electrode, and a piezoelectric body, wherein the piezoelectric body is located between the first electrode and the second electrode in the stacking direction of the first electrode, the second electrode, and the piezoelectric body. The vibrating plate, located on one side of the piezoelectric element in the stacking direction, is deformed by 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 pressure chamber whose volume changes due to the deformation of the vibrating plate. The nozzle ejects liquid in response to changes in the volume of the pressure chamber; as well as The temperature detection unit, located on the opposite side of the vibrating plate in the stacking direction, detects the temperature of the pressure chamber. According to regulations, a specified ejection cycle signal for the ejection cycle of liquid ejected from the ejection module is input to the temperature signal output circuit. The temperature detection unit then begins detecting the temperature of the pressure chamber and detects the temperature of the pressure chamber at different time intervals until the specified ejection cycle signal, followed by the next specified ejection cycle signal, is input to the temperature signal output circuit. The temperature signal output circuit outputs a temperature information signal corresponding to N temperature information, where N is a natural number greater than 2. The N temperature information corresponds to the temperature of the pressure chamber detected at different times during the ejection period by the temperature detection unit after the input of the ejection cycle specified signal and until the next input of the ejection cycle specified signal.

2. The printhead according to claim 1, characterized in that, The temperature information output circuit calculates the arithmetic mean of the N temperature information and outputs it as the temperature information signal.

3. The printhead according to claim 1, characterized in that, The temperature information output circuit calculates the adjusted average value of the N temperature information and outputs it as the temperature information signal.

4. The printhead according to claim 3, characterized in that, If, within the N temperature information points, the difference between the i-th temperature information point (from highest to lowest) and the N+1-i-th temperature information point (from highest to lowest) of the pressure chamber is greater than a predetermined threshold, and the difference between the (i+1)-th temperature information point (from highest to lowest) and the Ni-th temperature information point (from highest to lowest) of the pressure chamber is less than the predetermined threshold, the temperature information output circuit calculates the arithmetic mean of the N-2×i temperature information points within the N temperature information points where the pressure chamber temperature is lower than the i-th temperature information point and higher than the N+1-i-th temperature information point, and outputs this as the temperature information signal, where i is any natural number from 1 to N / 2.

5. The printhead according to any one of claims 1 to 4, characterized in that, The different timings are included during the period when the ejection module receives the drive signal and ejects liquid.

6. A liquid discharge apparatus characterized by comprising: have: The drive signal output circuit outputs the corrected drive signal. The calibration unit calibrates the drive signal; and The print head receives the drive signal and ejects liquid. The printhead has an ejection module and a temperature information output circuit. The ejection module receives the corrected drive signal and ejects liquid, and the temperature information output circuit outputs a temperature information signal representing the temperature of the ejection module. The ejection module has: A piezoelectric element is driven by receiving the corrected driving signal and includes a first electrode, a second electrode, and a piezoelectric body, wherein the piezoelectric body is located between the first electrode and the second electrode in the stacking direction of the first electrode, the second electrode, and the piezoelectric body. The vibrating plate, located on one side of the piezoelectric element in the stacking direction, is deformed by 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 pressure chamber whose volume changes due to the deformation of the vibrating plate. The nozzle ejects liquid in response to changes in the volume of the pressure chamber; as well as The temperature detection unit, located on the opposite side of the vibrating plate in the stacking direction, detects the temperature of the pressure chamber. According to regulations, a specified ejection cycle signal for the ejection cycle of liquid ejected from the ejection module is input to the temperature signal output circuit. The temperature detection unit then begins detecting the temperature of the pressure chamber and detects the temperature of the pressure chamber at different time intervals until the specified ejection cycle signal, followed by the next specified ejection cycle signal, is input to the temperature signal output circuit. The temperature signal output circuit outputs a temperature information signal corresponding to N temperature information, where N is a natural number greater than 2. The N temperature information corresponds to the temperature of the pressure chamber detected at different times during the ejection period by the temperature detection unit after the input of the ejection cycle specified signal and until the next input of the ejection cycle specified signal.

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