Liquid ejection apparatus, head unit control circuit, and liquid ejection inspection method

Abstract

The invention provides a liquid ejecting apparatus, a head unit control circuit, and a liquid ejecting inspection method, which can shorten the inspection time for determining the state of an ejecting portion. An inkjet printer includes: an ejection unit capable of ejecting ink according to an input drive signal; a signal generation unit to which a residual vibration signal corresponding to residual vibration generated in the discharge unit as the drive signal is input is input, and which generates a comparison signal on the basis of the residual vibration signal; and a determination unit that determines the state of the discharge unit on the basis of the comparison signal. The signal generation unit has: a first inspection mode for generating, as a comparison signal, a first inspection mode signal corresponding to a first partial signal in a first period of the residual vibration signal; and a second inspection mode for generating, as a comparison signal, a second inspection mode signal corresponding to a second partial signal in a second period of the residual vibration signal. The first period is shorter than the second period.

Description

Technical Field

[0001] This invention relates to a liquid ejection device, a head unit control circuit for controlling the head unit of the liquid ejection device, and a method for checking liquid ejection. Background Technology

[0002] Inkjet printers and other liquid ejection devices eject liquids such as ink filled in the ejection section of a liquid ejection head during each of a plurality of unit periods defined by a latching signal, thereby forming an image on a medium. However, in such liquid ejection devices, ejection abnormalities sometimes occur, where liquid cannot be ejected normally from the ejection section. Therefore, techniques for checking the ejection status of the ejection section have been proposed in the past. For example, Patent Document 1 discloses a technique for checking the ejection status of the ejection section based on a detection signal showing the vibration remaining in the ejection section after the ejection section is driven based on a drive signal.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2015-174267

[0004] However, according to conventional techniques, when inspecting the ejection state of the ejector section, noise occurs due to signal overlap immediately after the inspection begins. Therefore, a mask circuit-based approach is employed to address this noise. While this mask circuit-based approach is effective in improving inspection accuracy, it is a major cause of increased inspection time. Furthermore, when inspecting the ejection state, for example, periodicity data indicating the period of the detection signal showing residual vibration is generated after the mask is removed, requiring information equivalent to at least one cycle of the signal. This requirement to detect one cycle of the signal after mask removal is also a significant constraint on reducing inspection time. Summary of the Invention

[0005] To address the above problems, the liquid ejection device of the present invention comprises: an ejection section capable of ejecting liquid according to an input drive signal; a signal generation section receiving a residual vibration signal corresponding to residual vibration generated in the ejection section upon input of the drive signal, and generating a state check signal based on the residual vibration signal; and a determination section determining the state of the ejection section based on the state check signal. The signal generation section has: a first check mode that generates a first check mode signal corresponding to a first portion of the residual vibration signal within a first period as the state check signal; and a second check mode that generates a second check mode signal corresponding to a second portion of the residual vibration signal within a second period as the state check signal, wherein the first period is a shorter period than the second period.

[0006] Furthermore, the head unit control circuit of the present invention relates to a head unit control circuit having a jetting section capable of ejecting liquid according to an input drive signal, comprising: a signal generation unit that receives a residual vibration signal corresponding to residual vibration generated in the jetting section with the input of the drive signal and generates a state check signal based on the residual vibration signal; and a determination unit that determines the state of the jetting section based on the state check signal, the signal generation unit having: a first check mode that generates a first check mode signal corresponding to a first portion of the residual vibration signal within a first period as the state check signal; and a second check mode that generates a second check mode signal corresponding to a second portion of the residual vibration signal within a second period as the state check signal, the first period being a period shorter than the second period.

[0007] Furthermore, the liquid ejection inspection method of the present invention relates to a liquid ejection device having an ejection section capable of ejecting liquid according to an input drive signal. In this method, a state inspection signal is generated based on a residual vibration signal corresponding to residual vibration generated in the ejection section with the input of the drive signal. The state of the ejection section is determined based on the state inspection signal. When a first inspection mode is selected as the inspection mode for determining the state of the ejection section, a first inspection mode signal corresponding to a first portion of the residual vibration signal within a first period is generated as the state inspection signal. When a second inspection mode is selected as the inspection mode, a second inspection mode signal corresponding to a second portion of the residual vibration signal within a second period is generated as the state inspection signal. The first period is a shorter period than the second period. Attached Figure Description

[0008] Figure 1 This is a block diagram illustrating an example of the configuration of an inkjet printer according to a first embodiment of the present invention.

[0009] Figure 2 This is a perspective view showing an example of the general internal structure of an inkjet printer.

[0010] Figure 3 This is a cross-sectional view illustrating an example of the structure of the ejector section.

[0011] Figure 4 This is an explanatory diagram used to illustrate the ejection action of ink in the ejector section.

[0012] Figure 5 This is a top view showing an example of the nozzle configuration of the head unit.

[0013] Figure 6This is a block diagram showing an example of the structure of a head unit.

[0014] Figure 7 This is a block diagram illustrating an example of the configuration of a measurement circuit.

[0015] Figure 8 This is a timing diagram illustrating an example of the operation of an inkjet printer during a unit period.

[0016] Figure 9 This is a timing diagram illustrating an example of the operation of the signal generation unit.

[0017] Figure 10 It is an explanatory diagram used to illustrate the relationship between residual vibration signal, reset timing, and comparison signal.

[0018] Figure 11 This is an explanatory diagram used to illustrate the relationship between reset timing and amplitude calculated based on time length.

[0019] Figure 12 It is an explanatory diagram used to illustrate the relationship between reset timing and amplitude and rate of change of amplitude.

[0020] Figure 13 This is a flowchart illustrating an example of the actions of an inkjet printer when performing ejection status determination processing.

[0021] Figure 14 This is a block diagram illustrating an example of the configuration of the inspection unit according to the second embodiment.

[0022] Figure 15 This is an explanatory diagram used to illustrate the general outline of the reset timing adjustment.

[0023] Figure 16 It is an explanatory diagram used to illustrate the relationship between reset timing and amplitude and rate of change of amplitude.

[0024] Figure 17 This is a flowchart illustrating an example of the actions of an inkjet printer when performing ejection status determination processing.

[0025] Figure 18 This is a block diagram illustrating an example of the configuration of the inspection unit according to the third embodiment.

[0026] Figure 19 It is an explanatory diagram used to illustrate the relationship between residual vibration signal, reset timing, and comparison signal.

[0027] Figure 20 This is an explanatory diagram illustrating the general principles of sensitivity adjustment when determining the state of the ejector.

[0028] Figure 21This is an explanatory diagram used to illustrate the relationship between reset timing and amplitude calculated based on time length.

[0029] Figure 22 It is an explanatory graph used to illustrate the relationship between the time ratio of two time lengths and the amplitude and the rate of change of amplitude.

[0030] Figure 23 This is an illustrative diagram used to illustrate an example of the deviation between nozzles in amplitude calculated based on the length of time.

[0031] Figure 24 This is an illustrative diagram used to illustrate an example of amplitude calculation based on a time length where the time ratio of two time lengths has been changed.

[0032] Figure 25 This is a flowchart illustrating an example of the actions of an inkjet printer when performing ejection status determination processing.

[0033] Figure 26 This is a block diagram illustrating an example of the configuration of the inspection unit involved in the first variation.

[0034] Explanation of reference numerals in the attached figures

[0035] 1…Inkjet printer, 2…Control unit, 3…Head unit, 4…Drive signal generation unit, 6, 6A, 6B, 6C…Check unit, 7…Transport unit, 8…Maintenance unit, 22…Drive control unit, 31…Switching circuit, 32…Recording head, 33…Detection circuit, 60, 60A, 60B…Signal generation unit, 62…Comparison unit, 63…Adjustment unit, 64, 64A…Decision unit, 65, 65A, 66…Timing specification circuit, 67, 67A, 67B…Determination unit, 68…Amplitude calculation circuit, 69…Decision circuit, 310…Connection status indicator The circuit includes: 620, 621, 622… Comparison circuit; 630, 631, 632… Adjustment circuit; 670, 670A, 670B, 671, 671A, 671B, 672, 672A, 672B… Determining circuit; D… Ejector section; HCM… Head unit control module; HM… Head module; INVc1, INVc2, INV11, INV12, INV21, INV22… Inverter; N… Nozzle; SW11, SW12, SW21, SW22, SWc1, SWc2… Switch; TM… Check module. Detailed Implementation

[0036] Hereinafter, the embodiments for carrying out the present invention will be described with reference to the accompanying drawings. However, in the drawings, the dimensions and scales of the various parts are appropriately different from the actual dimensions. Furthermore, the embodiments described below are suitable specific examples of the present invention, and therefore various technically preferred limitations are attached, but the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

[0037] 1. Implementation Method

[0038] In this embodiment, an inkjet printer that ejects ink onto recording paper to form an image is used as an example to illustrate the liquid ejection device. Furthermore, in this embodiment, ink refers to an example of "liquid". First, refer to... Figure 1 The configuration of the inkjet printer 1 involved in this embodiment will be explained.

[0039] First Implementation Method

[0040] Figure 1 This is a block diagram illustrating an example of the configuration of an inkjet printer 1 according to a first embodiment of the present invention.

[0041] In inkjet printer 1, for example, printing data IMG showing an image to be formed by inkjet printer 1 is supplied from a host computer such as a personal computer or digital camera. Inkjet printer 1 performs a printing process to form the image shown in the printing data IMG supplied from the host computer onto a medium. In this embodiment, the medium is assumed to be the one described later. Figure 2 The recording paper P shown.

[0042] The inkjet printer 1 includes: a head module HM, comprising a head unit 3 having an ink ejection section D; and a head unit control module HCM, which controls the head unit 3. The inkjet printer 1 also includes: a transport unit 7 for changing the relative position of the recording paper P with respect to the head unit 3; and a maintenance unit 8 for performing maintenance procedures on the ink ejection section D provided in the head unit 3. Furthermore, the head unit control module HCM is an example of a "head unit control circuit".

[0043] The head unit control module (HCM) includes: a control unit 2 that controls various parts of the inkjet printer 1; and a drive signal generation unit 4 that generates drive signals COM for driving the ejector section D. Additionally, the head unit control module (HCM) includes: a storage unit 5 that stores various information such as printing data IMG and the control program PG of the inkjet printer 1; and a check module TM that includes a check unit 6 for determining the state of the ejector section D.

[0044] In this embodiment, it is assumed that the head unit 3 and the inspection unit 6 correspond to each other. For example, the inkjet printer 1 may have multiple head units 3 and multiple inspection units 6 corresponding one-to-one with the multiple head units 3. Alternatively, the inkjet printer 1 may have one head unit 3 and one inspection unit 6 corresponding to the one head unit 3. In this embodiment, it is assumed that the inkjet printer 1 has four head units 3 and four inspection units 6 corresponding one-to-one with the four head units 3. However, for ease of explanation, the following description focuses on one head unit 3 out of the four head units 3 and one inspection unit 6 out of the four inspection units 6 that corresponds to one head unit 3.

[0045] The control unit 2 is configured to include one or more CPUs (Central Processing Units). Alternatively, the control unit 2 may replace the CPU or incorporate programmable logic devices such as FPGAs (Field-Programmable Gate Arrays) on top of the CPU. Furthermore, the control unit 2 functions as a drive control unit 22 by executing the control program PG stored in the storage unit 5.

[0046] The drive control unit 22 generates signals such as the printing signal SI, the waveform specification signal dCOM, the pulse detection period signal Pcut, and the mask signal MSK to control the operation of each part of the inkjet printer 1. Here, the waveform specification signal dCOM is a digital signal that defines the waveform of the drive signal COM. The drive signal COM is an analog signal used to drive the ejector section D. The printing signal SI is a digital signal used to specify the type of operation of the ejector section D. Specifically, the printing signal SI specifies the type of operation of the ejector section D by specifying whether or not the drive signal COM is supplied to the ejector section D. The pulse detection period signal Pcut and the mask signal MSK will be discussed later. Figure 7 and Figure 8 The explanation is provided below.

[0047] When performing printing processing, for example, the drive control unit 22 controls the printing head unit 3 and the transport unit 7 to print the image shown in the printing data IMG onto the recording paper P. Specifically, when performing printing processing, the drive control unit 22 generates a printing signal SI or similar signal to control the head unit 3 based on the printing data IMG. Additionally, the drive control unit 22 generates a waveform specification signal dCOM or similar signal to control the drive signal generation unit 4. Furthermore, the drive control unit 22 generates a signal to control the transport unit 7. Thus, during printing processing, the drive control unit 22 controls the transport unit 7 in a manner that changes the relative position of the recording paper P relative to the head unit 3, while simultaneously adjusting whether ink is ejected from the ejection unit D, the amount of ink ejected, and the ink ejection timing. In this way, the drive control unit 22 controls each part of the inkjet printer 1 to form an image corresponding to the printing data IMG onto the recording paper P.

[0048] The drive signal generation unit 4 includes, for example, a DAC (Digital Analog Converter) that generates a drive signal COM based on a waveform specification signal dCOM supplied from the drive control unit 22. For example, the drive signal generation unit 4 generates a drive signal COM that includes the waveform specified by the waveform specification signal dCOM. The drive signal generation unit 4 outputs the drive signal COM generated based on the waveform specification signal dCOM to the switching circuit 31 included in the head unit 3. Furthermore, in this embodiment, it is assumed that the head units 3 correspond to each other with the drive signals COM. For example, the inkjet printer 1 may have four drive signal generation units 4, each corresponding to one of the four head units 3.

[0049] Storage unit 5 is configured to include one or both of volatile memory such as RAM (Random Access Memory) and non-volatile memory such as ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), or PROM (Programmable ROM). Furthermore, storage unit 5 may also be included in control unit 2. Storage unit 5 is an example of a "storage section".

[0050] The head unit 3 has a switching circuit 31, a recording head 32, and a detection circuit 33.

[0051] The recording head 32 has J ejector sections D. Furthermore, the value J is a natural number greater than or equal to 1. Hereinafter, the j-th ejector section D among the J ejector sections D provided in the recording head 32 is sometimes referred to as ejector section D[j]. Here, the variable j is a natural number satisfying "1≤j≤J". Additionally, hereafter, when the constituent elements or signals of the inkjet printer 1 correspond to ejector section D[j] among the J ejector sections D, the reference numerals used to represent that constituent element or signal are sometimes marked with a subscript [j].

[0052] The switching circuit 31 switches whether to supply the drive signal COM to the ejector section D[j] based on the printing signal SI. Furthermore, as will be described later... Figure 6 As shown, the drive signal COM supplied to the ejector section D[j] is sometimes referred to as the independent drive signal Vin[j]. The drive signal COM and the independent drive signal Vin are examples of "drive signals".

[0053] Furthermore, the switching circuit 31 switches whether to electrically connect the ejector section D[j] to the detection circuit 33 based on the printing signal SI. When the ejector section D[j] is electrically connected to the detection circuit 33, for example, the detection signal Vout[j] detected from the ejector section D[j] is supplied to the detection circuit 33 via the switching circuit 31. The detection signal Vout[j] is, for example, a simulated signal showing the change in the potential of the upper electrode Zu[j] of the piezoelectric element PZ[j] provided in the ejector section D[j]. For example, the detection signal Vout[j] is a residual vibration signal generated by the vibration remaining in the ejector section D[j] after the piezoelectric element PZ[j] is driven by the independent drive signal Vin[j]. In this case, the waveform of the detection signal Vout[j] shows, for example, the waveform of the residual vibration of the ejector section D[j] after the piezoelectric element PZ[j] is driven. The residual vibration of the ejector portion D[j] after the piezoelectric element PZ[j] is driven corresponds to the residual vibration of the vibrating plate 321 after the piezoelectric element PZ[j] is driven. Furthermore, regarding the piezoelectric element PZ, the upper electrode Zu[j], and the vibrating plate 321, [further details will be provided later]. Figure 3 This will be discussed later.

[0054] The detection circuit 33 generates a residual vibration signal VD[j] corresponding to the detection signal Vout[j] as a signal used to determine the state of the ejection section D[j]. For example, the detection circuit 33 shapes the detection signal Vout[j] into a waveform suitable for processing by the inspection unit 6 by amplifying the amplitude of the detection signal Vout[j] or removing noise components contained in the detection signal Vout[j]. Thus, the residual vibration signal VD[j] is generated. For example, the detection circuit 33 may be configured to include a negative feedback amplifier for amplifying the detection signal Vout[j], a low-pass filter for attenuating the high-frequency components of the detection signal Vout[j], and a voltage follower for impedance transformation and outputting a low-impedance residual vibration signal VD[j].

[0055] For example, the residual vibration signal VD[j] generated based on the detection signal Vout[j] is a simulated signal showing the waveform of the residual vibration of the vibrating plate 321 after the piezoelectric element PZ[j] is driven by the independent drive signal Vin[j]. The detection circuit 33 outputs the residual vibration signal VD[j] generated based on the detection signal Vout[j] to the inspection unit 6. In this way, the detection circuit 33 detects the residual vibration of the vibrating plate 321 caused by driving the piezoelectric element PZ[j] based on the detection signal Vout[j].

[0056] The inspection unit 6 determines the state of the ejector section D[j] based, for example, on the residual vibration signal VD[j]. Furthermore, in Figure 1 This section provides a brief overview of inspection unit 6; details about inspection unit 6 will be discussed later. Figure 7 The following explanation is provided. Furthermore, in this embodiment, the inspection unit 6 is assumed to have both a first inspection mode and a second inspection mode as the inspection mode for determining the state of the ejection section D. For example, the first inspection mode is the inspection mode that determines the state of the ejection section D[j] with a shorter inspection time than the second inspection mode. Therefore, in this embodiment, selecting the first inspection mode as the inspection mode can shorten the inspection time. Moreover, in this embodiment, selecting the second inspection mode as the inspection mode can determine multiple state abnormalities, including the viscosity state of the ink within the ejection section D.

[0057] The inspection unit 6 includes, for example, a signal generation unit 60 that generates a state inspection signal based on a residual vibration signal VD, and a determination unit 64 that determines the state of the ejection section D based on the state inspection signal. For example, the determination unit 64 determines the state of the ejection section D based on the state inspection signal generated by the signal generation unit 60 and generates state information Cinf containing information showing the result of the determination. Examples of states of the ejection section D include, for instance, the viscosity of the ink within the ejection section D. For example, the determination unit 64 uses the state inspection signal generated based on the residual vibration signal VD[j] to determine the viscosity of the ink within the ejection section D[j]. In this case, it is possible to suppress printing processing in an abnormal state caused by the viscosity of the ink within the ejection section D[j]. Hereinafter, the process of determining the state of the ejection section D[j] is also referred to as the ejection state determination process. Furthermore, hereafter, the ejection section D whose state is determined is also referred to as the ejection section D subject to determination.

[0058] When performing the ejection state determination process, the drive control unit 22 generates a printing signal SI or similar signal to control the head unit 3. Additionally, when performing the ejection state determination process, the drive control unit 22 generates a waveform specification signal dCOM or similar signal to control the drive signal generation unit 4. Thus, the drive control unit 22 drives the ejection section D[j], which is the determination target.

[0059] Furthermore, during the ejection state determination process, the drive control unit 22 controls the head unit 3 by generating a printing signal SI to supply a detection signal Vout[j] corresponding to the ejection section D[j] driven by the ejection section D being determined to the test to the detection circuit 33. As a result, the detection circuit 33 generates a residual vibration signal VD[j] corresponding to the detection signal Vout[j] detected from the ejection section D[j] driven by the ejection section D being determined to the test. Then, the inspection unit 6 determines the state of the ejection section D[j] driven by the ejection section D being determined to the test based on the residual vibration signal VD[j] supplied from the detection circuit 33. Additionally, the inspection unit 6 outputs state information Cinf, which includes information indicating the determination result of the state of the ejection section D[j], to the control unit 2.

[0060] Furthermore, the inspection unit 6 may also be included in the control unit 2. For example, the control unit 2 may also function as the inspection unit 6 by operating according to the control program PG stored in the storage unit 5.

[0061] Furthermore, as described above, in this embodiment, the inkjet printer 1 performs maintenance procedures. For example, the maintenance procedures include: rinsing to remove ink from the ejection section D; wiping to remove foreign matter such as ink adhering to the nozzle N of the ejection section D using a wiper; and pumping to draw ink from the ejection section D using a tubular pump or the like. Regarding the nozzle N, [further details will be provided later]. Figure 3 This will be discussed later.

[0062] For example, the ink with increased viscosity is discharged from the ejection section D after a rinsing process. This allows the viscosity of the ink in the nozzle N at the start of the printing process to be below a specified viscosity. In this case, the viscous ink is discharged from the ejection section D, thus suppressing any degradation in the quality of the image printed through the printing process.

[0063] The maintenance unit 8 includes: an ink discharge receiving section 80 for receiving ink discharged from the ejector section D during rinsing; a wiper for wiping away foreign matter such as ink adhering to the nozzle N of the ejector section D; and a pipe pump for drawing ink or air bubbles from the ejector section D. Furthermore, regarding the ink discharge receiving section 80, [details to be added]. Figure 2 This will be discussed later. Additionally, illustrations of the wiper and tubing pump are omitted. Next, refer to... Figure 2 This describes the general internal structure of inkjet printer 1.

[0064] Figure 2 This is a perspective view showing an example of the schematic internal structure of an inkjet printer 1.

[0065] like Figure 2 As shown, in this embodiment, it is assumed that the inkjet printer 1 is a serial printer. Specifically, when performing printing processing, the inkjet printer 1 conveys the recording paper P in the sub-scanning direction while reciprocating the head module HM in the main scanning direction that intersects the sub-scanning direction, and ejects ink from the ejection section D[j], thereby forming dots on the recording paper P corresponding to the printing data IMG.

[0066] For ease of explanation, an orthogonal coordinate system with three mutually orthogonal axes (X-axis, Y-axis, and Z-axis) will be appropriately introduced below. For example, in this embodiment, the Y1 direction along the Y-axis will be designated as the secondary scanning direction, and the X1 and X2 directions along the X-axis will be designated as the primary scanning directions. Furthermore, the X2 direction is the opposite direction to the X1 direction. Additionally, in this embodiment, as in... Figure 2As illustrated, the Z1 direction along the Z-axis is defined as the ejection direction of ink from the ejection section D[j]. Furthermore, hereinafter, the X1 and X2 directions will be collectively referred to as the X-axis direction, the Y1 direction and the opposite Y2 direction will be collectively referred to as the Y-axis direction, and the Z1 direction and the opposite Z2 direction will be collectively referred to as the Z-axis direction. In addition, in this embodiment, as described above, it is assumed that the X-axis, Y-axis, and Z-axis are orthogonal to each other, but the present invention is not limited to such a solution. For example, the X-axis, Y-axis, and Z-axis may simply intersect each other.

[0067] The inkjet printer 1 according to this embodiment has a frame 100 and a carriage 110 that can reciprocate in the X-axis direction within the frame 100. A head module HM including four head units 3 is mounted on the carriage 110.

[0068] In this embodiment, it is assumed that the carriage 110 stores four ink cartridges 120, each corresponding to one of the four colors of ink: cyan, magenta, yellow, and black. Similarly, in this embodiment, it is assumed that four head units 3 correspond one-to-one with four ink cartridges 120. Each ejector section D[j] receives ink from the ink cartridge 120 corresponding to the head unit 3 on which the ejector section D[j] is located. Thus, each ejector section D[j] can fill its interior with the supplied ink and eject the filled ink from the nozzle N. Alternatively, the ink cartridges 120 may be located outside the carriage 110.

[0069] Furthermore, the inkjet printer 1 involved in this embodiment, as in... Figure 1 As described above, the conveying unit 7 includes: a carriage conveying mechanism 71 for reciprocating the carriage 110 in the X-axis direction; and a carriage guide shaft 76 for freely reciprocating and supporting the carriage 110 in the X-axis direction. Furthermore, the conveying unit 7 includes: a media conveying mechanism 73 for conveying the recording paper P; and an impression plate 75 disposed relative to the carriage 110 in the Z1 direction. For example, in the printing process, the carriage conveying mechanism 71 causes the head module HM to reciprocate along the carriage guide shaft 76 in the X-axis direction together with the carriage 110, while the media conveying mechanism 73 conveys the recording paper P on the impression plate 75 in the Y1 direction. Therefore, by performing the above-described actions of the carriage conveying mechanism 71 and the media conveying mechanism 73 in the printing process, the conveying unit 7 can change the relative position of the recording paper P relative to the head module HM, enabling ink to drip onto the entire recording paper P.

[0070] Next, refer to Figure 3 To illustrate the general structure of the record header 32.

[0071] Figure 3 This is a cross-sectional view illustrating an example of the structure of the ejector section D. Furthermore, in Figure 3The diagram schematically shows a portion of the cross-section of the recording head 32 when it is cut off in a manner that includes the ejection portion D[j].

[0072] The ejection section D[j] includes: a cavity CV filled with ink; a nozzle N communicating with the cavity CV; a piezoelectric element PZ[j] that generates pressure variations in the ink within the cavity CV by being supplied with an independent drive signal Vin[j]; and a vibrating plate 321. The ejection section D[j] is driven by the piezoelectric element PZ[j] and the independent drive signal Vin[j], thereby ejecting the ink from the cavity CV from the nozzle N.

[0073] The cavity CV corresponds to a pressure chamber connected to the nozzle N. For example, the cavity CV is a space divided by the cavity plate 324, the nozzle plate 323 on which the nozzle N is formed, and the vibrating plate 321. The cavity CV is connected to the reservoir 325 via the ink supply port 326. The reservoir 325 is connected to the ink cartridge 120 corresponding to the ejection section D[j] via the ink inlet 327. The piezoelectric element PZ[j] has an upper electrode Zu[j], a lower electrode Zd[j], and a piezoelectric body Zb[j] disposed between the upper electrode Zu[j] and the lower electrode Zd[j]. The piezoelectric body Zb[j] is formed, for example, of a ferroelectric piezoelectric material.

[0074] The upper electrode Zu[j] is electrically connected to the wiring Li, which supplies the independent drive signal Vin[j]. The lower electrode Zd[j] is electrically connected to the wiring Ld, which supplies the base potential signal VBS. Then, by supplying the upper electrode Zu[j] with the independent drive signal Vin[j], a voltage is applied between the upper electrode Zu[j] and the lower electrode Zd[j]. The piezoelectric element PZ[j] is displaced in either the Z1 or Z2 direction according to the voltage applied between the upper electrode Zu[j] and the lower electrode Zd[j].

[0075] Thus, the piezoelectric element PZ[j] vibrates according to the voltage applied between the upper electrode Zu[j] and the lower electrode Zd[j]. The vibrating plate 321 is engaged with the lower electrode Zd[j]. Therefore, the piezoelectric element PZ[j] is driven and vibrates by the independent drive signal Vin[j], thereby causing the vibrating plate 321 to vibrate as well. Furthermore, due to the vibration of the vibrating plate 321, the volume of the cavity CV and the pressure within the cavity CV change, causing the ink filled into the cavity CV to be ejected from the nozzle N.

[0076] In this embodiment, as an example, it is assumed that the piezoelectric element PZ shifts in the Z1 direction due to the change in potential of the independent drive signal Vin[j] supplied to the ejector D[j] from a low potential to a high potential. That is, in this embodiment, it is assumed that when the potential of the independent drive signal Vin[j] supplied to the ejector D[j] is high, the volume of the cavity CV of the ejector D[j] is smaller compared to the case of a low potential.

[0077] Next, refer to Figure 4 To explain the ink ejection action in ejection section D.

[0078] Figure 4 This is an explanatory diagram used to illustrate the ink ejection action in the ejection section D.

[0079] The drive control unit 22, for example, in Phase-1, generates strain such that the piezoelectric element PZ, supplied to the ejector section D, is displaced in the Z2 direction due to a potential change caused by the drive signal COM. As a result, the vibrating plate 321 of the ejector section D flexes in the Z2 direction. Consequently, as... Figure 4 As shown in Phase-2, compared to Phase-1, the volume of the cavity CV of the ejector section D is increased. Next, the drive control unit 22, for example in Phase-2, generates strain such that the piezoelectric element PZ is displaced in the Z1 direction by changing the potential of the drive signal COM. As a result, the vibrating plate 321 of the ejector section D flexes in the Z1 direction. Consequently, as... Figure 4 As shown in Phase-3, the volume of the cavity CV shrinks sharply, and a portion of the ink filling the cavity CV is ejected as ink droplets from the nozzle N connected to the cavity CV.

[0080] Thus, the piezoelectric element PZ and the vibrating plate 321 in the ejection section D are displaced in the Z-axis direction by the drive signal COM driven by the piezoelectric element PZ in the ejection section D. Therefore, residual vibration is generated in the ejection section D including the vibrating plate 321 after the piezoelectric element PZ is driven by the drive signal COM.

[0081] Next, refer to Figure 5 Here is an example illustrating the configuration of nozzle N.

[0082] Figure 5 This is a top view showing an example of the configuration of nozzle N in head unit 3. Furthermore, in Figure 5 The image shows an example of the configuration of the head module HM having four head units 3 and a total of 4J nozzles N disposed on the four head units 3, viewed from above in the Z1 direction.

[0083] Each head unit 3 of the head module HM provided on the carriage 110 is provided with a nozzle row NL. Here, a nozzle row NL refers to a plurality of nozzles N arranged in a row extending in a predetermined direction. In this embodiment, it is assumed that each nozzle row NL is composed of J nozzles N arranged to extend in the Y-axis direction as an example.

[0084] Next, refer to Figure 6 Let me explain the overview of Head Unit 3.

[0085] Figure 6 This is a block diagram showing an example of the configuration of head unit 3.

[0086] Head unit 3, as in Figure 1 As described, it includes a switching circuit 31, a recording head 32, and a detection circuit 33. Furthermore, the head unit 3 includes: a wiring La, which receives a drive signal COM from the drive signal generation unit 4; and a wiring Ls, which supplies a detection signal Vout to the detection circuit 33. The head unit 3 also includes: a wiring Li[j], which supplies an independent drive signal Vin[j] to the ejection section D[j]; and a wiring Ld, which receives a base potential signal VBS.

[0087] The switching circuit 31 has: J switches SWA[1] to SWA[J], which correspond one-to-one with J ejector parts D[1] to D[J]; J switches SWs[1] to SWs[J], which correspond one-to-one with J ejector parts D[1] to D[J]; and a connection state designation circuit 310.

[0088] The connection state specifying circuit 310 specifies the connection state of each of the J switches SWA and J switches SWs. For example, the connection state specifying circuit 310 generates connection state specifying signals Qa[j] and Qs[j] based on at least a portion of the printed signal SI, latch signal LAT, and period specifying signal Tsig supplied from the drive control unit 22. The connection state specifying signal Qa[j] is the signal that specifies the on / off state of switch SWA[j], and the connection state specifying signal Qs[j] is the signal that specifies the on / off state of switch SWs[j].

[0089] In this embodiment, it is assumed that the J switches SWA and J switches SWs are each composed of transmission gates containing P-channel transistors and N-channel transistors connected in parallel. However, the J switches SWA and J switches SWs can also be composed of either P-channel transistors or N-channel transistors.

[0090] The switch SWA[j] switches the connection between wiring La and the upper electrode Zu[j] of the piezoelectric element PZ[j] located in the ejector section D[j] based on the connection state specification signal Qa[j]. That is, the switch SWA[j] switches the connection between wiring La and wiring Li[j] connected to the upper electrode Zu[j] based on the connection state specification signal Qa[j]. In this embodiment, the switch SWA[j] is turned on when the connection state specification signal Qa[j] is high and turned off when the connection state specification signal Qa[j] is low. When the switch SWA[j] is on, the drive signal COM supplied to wiring La is supplied as an independent drive signal Vin[j] to the upper electrode Zu[j] of the ejector section D[j] via wiring Li[j]. That is, the independent drive signal Vin[j] is the drive signal COM supplied to the piezoelectric element PZ[j] of the ejector section D[j] via the switch SWA[j].

[0091] The switch SWs[j] switches the connection between wiring Ls and the upper electrode Zu[j] of the piezoelectric element PZ[j] located in the ejector section D[j] based on the connection state specification signal Qs[j]. That is, the switch SWs[j] switches the connection between wiring Ls and wiring Li[j] connected to the upper electrode Zu[j] based on the connection state specification signal Qs[j]. In this embodiment, the switch SWs[j] is turned on when the connection state specification signal Qs[j] is high and turned off when the connection state specification signal Qs[j] is low.

[0092] For example, the connection status designation signal Qs[j] becomes high when residual vibration of the ejector section D[j] is detected. Thus, residual vibration of the ejector section D, the object to be judged, is detected. Switch SWs[j] is turned on, thereby supplying a detection signal Vout[j] indicating the potential of the upper electrode Zu[j] of the piezoelectric element PZ[j] of the ejector section D[j], the object to be judged, to the detection circuit 33 via wiring Li[j] and wiring Ls. Then, the detection circuit 33 generates a residual vibration signal VD[j] based on the detection signal Vout[j]. The residual vibration signal VD[j] is supplied to the signal generation unit 60 of the inspection unit 6.

[0093] Furthermore, the supply of the residual vibration signal VD[j] to the signal generation unit 60 is terminated by disconnecting the switch SWs[j]. For example, by disconnecting the switch SWs[j], wiring Ls and wiring Li[j] become non-conductive, thus blocking the signal path of the residual vibration signal VD from the ejector D to the signal generation unit 60. That is, the signal generation unit 60 becomes electrically disconnected from the ejector D[j] by the connection state specifying signal Qs[j]. For example, the timing of the connection state specifying signal Qs[j] changing from a high level to a low level corresponds to the blocking timing of the signal path of the residual vibration signal VD from the ejector D to the signal generation unit 60 being blocked. Furthermore, the connection state specifying signal Qs is an example of a "blocking signal". In addition, in the signal path of the residual vibration signal VD from the ejector D[j] to the signal generation unit 60, one of wiring Ls and wiring Li[j] corresponds to the "first signal path", and the other of wiring Ls and wiring Li[j] corresponds to the "second signal path".

[0094] Next, refer to Figure 7 Let's explain the inspection unit 6.

[0095] Figure 7 This is a block diagram illustrating an example of the configuration of inspection unit 6. Inspection unit 6 is as follows... Figure 1 As described herein, it has a signal generation unit 60 and a determination unit 64.

[0096] The signal generation unit 60 may include, for example, a comparison unit 62 that includes comparison circuits 620, 621 and 622, and an adjustment unit 63 that includes adjustment circuits 630, 631 and 632.

[0097] The comparison circuits 620, 621 and 622 of the comparison unit 62 each binarize the residual vibration signal VD by comparing it with a threshold.

[0098] Comparison circuit 620 compares, for example, the potential of residual vibration signal VD with a threshold potential VthC, and generates a comparison signal CPc indicating the comparison result. Specifically, comparison circuit 620 generates a comparison signal CPc that is high when the potential of residual vibration signal VD is above the threshold potential VthC, and low when the potential of residual vibration signal VD is below the threshold potential VthC.

[0099] Additionally, the comparator circuit 621 compares, for example, the potential of the residual vibration signal VD with the threshold potential Vth1, generating a comparison signal CP1 that indicates the comparison result. Specifically, the comparator circuit 621 generates a comparison signal CP1 that is high when the potential of the residual vibration signal VD is above the threshold potential Vth1, and low when the potential of the residual vibration signal VD is below the threshold potential Vth1.

[0100] Additionally, the comparator circuit 622 compares, for example, the potential of the residual vibration signal VD with the threshold potential Vth2, and generates a comparison signal CP2 indicating the comparison result. Specifically, the comparator circuit 622 generates a comparison signal CP2 that is high when the potential of the residual vibration signal VD is above the threshold potential Vth2, and low when the potential of the residual vibration signal VD is below the threshold potential Vth2.

[0101] Furthermore, in this embodiment, the threshold potential VthC is the potential at the center level of the amplitude of the residual vibration signal VD, and the threshold potentials VthC, Vth1, and Vth2 satisfy "VthC < Vth2 < Vth1". Additionally, in this embodiment, the threshold potentials VthC, Vth1, and Vth2 satisfy "|Vth2 - VthC| < |Vth1 - VthC|". The threshold potential VthC is an example of a "first potential", and the threshold potentials Vth1 and Vth2 are examples of a "second potential".

[0102] Comparison signals CPC, CP1, and CP2 are supplied to the adjustment circuits 630, 631, and 632 of the adjustment unit 63, respectively. Hereinafter, comparison signals CPC, CP1, and CP2 will be collectively referred to as comparison signal CP. Comparison signal CP is an example of a "check signal". Moreover, comparison signal CPc in comparison signal CP is equivalent to a "reference signal".

[0103] The adjustment unit 63 generates comparison signals CCPc, CCP1, and CCP2 based on the pulse detection period signal Pcut and mask signal MSK supplied from the control unit 2, and the comparison signals CPc, CP1, and CP2 supplied from the comparison unit 62. Hereinafter, comparison signals CCPc, CCP1, and CCP2 will sometimes be collectively referred to as comparison signal CCP. Comparison signal CCP is an example of a "status check signal".

[0104] Furthermore, the signal Pcut during pulse detection is described later. Figure 9 The diagram shows the signal that specifies the reset timing tep for resetting the comparison signal CCP. For example, during pulse detection, the signal Pcut is maintained at a high level while the comparison signal CP is active as a signal used in the generation of the comparison signal CCP. The signal Pcut during pulse detection is an example of a "reset signal".

[0105] Furthermore, the mask signal MSK is a signal that is invalid during the masking period, as the comparison signal CP is defined as the signal used in the generation of the comparison signal CCP in the second inspection mode. Therefore, the residual vibration signal VD during the masking period cannot be used in determining the state of the ejection section D. In this embodiment, it is assumed that the mask signal MSK is maintained at a high level during the masking period. For example, in the second inspection mode, the mask signal MSK is maintained at a high level from the time the switch SWs[j] is turned on until a predetermined time has elapsed, and then changes to a low level after the predetermined time has elapsed. In addition, in the first inspection mode, the mask signal MSK is maintained at a low level.

[0106] For example, the adjustment circuit 630 of the adjustment unit 63 generates a comparison signal CCPc, which represents the logical product of the inverted mask signal MSK, the pulse detection period signal Pcut, and the comparison signal CPC. Therefore, the potential of the comparison signal CCPc after the reset timing tep specified by the pulse detection period signal Pcut is maintained at a low level regardless of the level of the comparison signal CCPc. Furthermore, the inverted mask signal MSK is, for example, a signal that is high when the mask signal MSK is low and low when the mask signal MSK is high.

[0107] Furthermore, the adjustment circuit 631 included in the adjustment unit 63 generates, for example, a comparison signal CCP1 that represents the logical product of the inverted mask signal MSK, the pulse detection period signal Pcut, and the comparison signal CP1. Thus, the potential of the comparison signal CCP1 after the reset timing tep specified by the pulse detection period signal Pcut is maintained at a low level regardless of the level of the comparison signal CP1.

[0108] Furthermore, the adjustment circuit 632 included in the adjustment unit 63 generates, for example, a comparison signal CCP2, which is the logical product of the inverted mask signal MSK, the pulse detection period signal Pcut, and the comparison signal CP2. Thus, the potential of the comparison signal CCP2 after the reset timing tep specified by the pulse detection period signal Pcut is maintained at a low level regardless of the level of the comparison signal CP2.

[0109] The comparison signals CCPc, CCP1, and CCP2 generated by the adjustment circuits 630, 631, and 632, respectively, are supplied to the determination unit 64. Furthermore, for example, when the masking timing is earlier than the reset timing tep, the comparison signal CCPc corresponds to the potential of the comparison signal CPc at its masking timing being maintained until the reset timing tep. Similarly, the comparison signal CCP1 corresponds to the potential of the comparison signal CP1 at its masking timing being maintained until the reset timing tep, and the comparison signal CCP2 corresponds to the potential of the comparison signal CP2 at its masking timing being maintained until the reset timing tep.

[0110] Here, since the potential of the comparison signal CCP is maintained at a low level after the reset timing tep, regardless of the level of the comparison signal CP, the reset timing tep is also captured as the timing of the end of the pulse of the comparison signal CCP.

[0111] The determination unit 64 includes a determination unit 67 comprising determination circuits 670, 671 and 672, an amplitude calculation circuit 68 and a determination circuit 69.

[0112] The determination unit 67 determines, for example, the duration of the period during which the comparison signals CCPc, CCP1, and CCP2 are maintained at a high level. For example, the comparison signals CCPc, CCP1, and CCP2 are supplied to the determination circuits 670, 671, and 672 included in the determination unit 67, respectively. Furthermore, for example, the determination circuit 670 determines the duration TCc of the period WCc during which the comparison signal CCPc is high, and outputs time information NTCc showing this duration TCc to the amplitude calculation circuit 68. In this embodiment, the duration WCc for determining the duration TCc is as described later. Figure 9 As shown, this period is later than the time t0 when the residual vibration signal VD is supplied to the signal generation unit 60, and it is the period during which the comparison signal CCPc is initially maintained at a high level.

[0113] Additionally, the determining circuit 671 determines the duration TC1 of the period WC1 during which the comparison signal CCP1 is high, and outputs the time information NTC1, which shows this duration TC1, to the amplitude calculation circuit 68. Here, the duration WC1 for determining the duration TC1 is as follows: Figure 9 The figure shows the period after time t0, and the period during which the comparison signal CCP1 was initially held at a high level.

[0114] Additionally, the determining circuit 672 determines the duration TC2 of the period WC2 during which the comparison signal CCP2 is high, and outputs the time information NTC2, which shows this duration TC2, to the amplitude calculation circuit 68. Here, the duration WC1 for determining the duration TC2 is as follows: Figure 9As shown, this is the period after time t0, and the period during which the comparison signal CCP2 is initially held high. Hereinafter, the time lengths TCc, TC1, and TC2 will sometimes be collectively referred to as the time length TC, and the time information NTCc, NTC1, and NTC2 will be collectively referred to as the time information NTC. The time information NTC is an example of "checking signal information".

[0115] Amplitude calculation circuit 68, for example, calculates the equivalent of Figure 9 The amplitude Vamp of the residual vibration signal VD is shown. Furthermore, the amplitude Vamp corresponding to the amplitude VPK of the residual vibration signal VD includes the same amplitude as the amplitude VPK of the residual vibration signal VD, the amplitude after amplifying the amplitude VPK of the residual vibration signal VD, and the amplitude after attenuating the amplitude VPK of the residual vibration signal VD. Hereinafter, the amplitude Vamp corresponding to the amplitude VPK of the residual vibration signal VD will sometimes be simply referred to as the amplitude Vamp of the residual vibration signal VD.

[0116] Furthermore, in this embodiment, the amplitude calculation circuit 68, as a calculation mode for calculating the amplitude Vamp of the residual vibration signal VD, has a first calculation mode and a second calculation mode. For example, in the first calculation mode, the amplitude calculation circuit 68 calculates the amplitude Vamp based on the time lengths TCc and TC1 and the threshold potentials VthC and Vth1. In the second calculation mode, the amplitude calculation circuit 68 calculates the amplitude Vamp based on the time lengths TCc and TC2 and the threshold potentials VthC and Vth2.

[0117] The amplitude Vamp is represented by equation (1) in the first calculation mode and by equation (2) in the second calculation mode. Furthermore, equations (1) and (2) below are formulas for calculating the amplitude Vamp by approximating the waveform of the residual vibration signal VD as a sine wave.

[0118] [Mathematical Expression 1]

[0119]

[0120] Which calculation mode, the first or the second, is used to calculate the amplitude Vamp can be predetermined for each nozzle N. Alternatively, the amplitude calculation circuit 68 can also determine which calculation mode to use based on the time length TC1. Specifically, for example, the amplitude calculation circuit 68 may use the first calculation mode to calculate the amplitude Vamp when the time length TC1 is longer than a first reference time, and use the second calculation mode when the time length TC1 is shorter than a second reference time (below the first reference time). Furthermore, if the time length TC1 is above the second reference time but below the first reference time, the previous calculation mode may also be used to calculate the amplitude Vamp. The initial calculation mode is, for example, the first calculation mode. In the above example, the switching of the calculation mode has hysteresis characteristics, but the switching of the calculation mode may also not have hysteresis characteristics.

[0121] The amplitude calculation circuit 68 outputs amplitude information NVamp, which shows the amplitude Vamp, as waveform information showing the characteristics of the residual vibration signal VD to the determination circuit 69. Here, the characteristics of the residual vibration signal VD refer to information related to the shape of the waveform of the residual vibration signal VD, such as the amplitude VPK or period of the residual vibration signal VD. In this embodiment, as described above, it is assumed that the amplitude information NVamp, which shows the amplitude Vamp corresponding to the amplitude VPK of the residual vibration signal VD, is supplied to the determination circuit 69 as waveform information.

[0122] The determination circuit 69 determines the ejection state of the ink in the ejection section D based on the amplitude Vamp of the residual vibration signal VD, and generates state information Cinf containing information indicating the result of the determination. Furthermore, for example, when the inspection mode is the second inspection mode, the determination circuit 69 can also obtain, in addition to the amplitude information NVamp, the time length TCc indicating the period when the comparison signal CCPc is high, as waveform information. In this case, the determination circuit 69 can determine the ejection state of the ink in the ejection section D based on the amplitude Vamp and the time length TCc of the residual vibration signal VD. Furthermore, as a method for determining the state of the ejection section D based on the amplitude Vamp of the residual vibration signal VD, known methods such as those based on the amplitude VPK of the residual vibration signal VD can be used.

[0123] Next, refer to Figure 8 To illustrate the operation of inkjet printer 1.

[0124] Figure 8This is a timing diagram illustrating an example of the operation of an inkjet printer 1 within a unit period TU. In this embodiment, when the inkjet printer 1 performs printing processing or ejection state determination processing, one or more unit periods TU are set as the operation period of the inkjet printer 1. The inkjet printer 1 according to this embodiment can drive each ejection section D[j] in each unit period TU for performing printing processing or ejection state determination processing. For example, when the inkjet printer 1 performs ejection state determination processing, it can drive the ejection section D of the determined object and detect the detection signal Vout[j] from the ejection section D of the determined object in each unit period TU.

[0125] Control unit 2 outputs a latched signal LAT with a pulse PlsL. Therefore, control unit 2 defines the unit period TU as the period from the rise of pulse PlsL to the rise of the next pulse PlsL.

[0126] The printing signal SI includes, for example, J independent designation signals Sd[1] to Sd[J] corresponding one-to-one with J ejector sections D[1] to D[J]. The independent designation signal Sd[j] specifies the driving scheme of the ejector section D[j] within each unit period TU when the inkjet printer 1 performs printing processing or ejection state determination processing. For example, before each unit period TU, the control unit 2 supplies the printing signal SI, which includes the independent designation signals Sd[1] to Sd[J], to the connection state designation circuit 310 after synchronizing it with the clock signal CL. Then, in that unit period TU, the connection state designation circuit 310 generates connection state designation signals Qa[j] and Qs[j] based on the independent designation signals Sd[j].

[0127] For example, during a unit period TU of printing processing, the ejector section D[j] is designated by an independent designation signal Sd[j] as either an ejector section D that forms a dot or an ejector section D that does not form a dot. Additionally, for example, during a unit period TU of ejection state determination processing, the ejector section D[j] is designated by an independent designation signal Sd[j] as whether it is driven as an ejector section D subject to determination. Furthermore, in Figure 8 The diagram illustrates the connection state designation signals Qa[j] and Qs[j], etc., when the ejection section D[j] in a unit period TU during which the ejection state determination process is designated as the ejection section D to be determined by the independent designation signal Sd[j]. Figure 8 The explanation focuses on the operation of inkjet printer 1 when performing ejection status determination processing. Additionally, in Figure 8 In this case, it is assumed that the inspection mode is the first inspection mode. In this case, the mask signal MSK is maintained at a low level for a unit period TU.

[0128] When performing ejection state determination processing, for example, the control unit 2 outputs a period-defined signal Tsig with pulses PlsT1 and PlsT2. Thus, the control unit 2 divides the unit period TU into a control period TSS1 from the start of pulse PlsL to the start of pulse PlsT1, and a control period TSS2 from the start of pulse PlsT1 to the start of the next pulse PlsL.

[0129] Furthermore, the control unit 2 defines the effective period TPval of the comparison signal CP by controlling the pulse detection period signal Pcut. For example, the drive control unit 22 of the control unit 2 sets the pulse detection period signal Pcut to a high level at the end of pulse PlsT1 and sets it to a low level at the beginning of pulse PlsT2. In this case, the period during which the logical product of the inverted mask signal MSK and the pulse detection period signal Pcut is high corresponds to the effective period TPval. In the first inspection mode, as... Figure 8 As shown, during the unit period TU, the mask signal MSK is maintained at a low level. Therefore, the period during which the pulse detection signal Pcut is at a high level is equivalent to the effective period TPval.

[0130] Additionally, the drive signal COM used for ejection state determination processing includes, for example, a pulse PA supplied to line La during the control period (TSS1). The pulse PA used for ejection state determination processing can be either a pulse that causes the vibrator 321 to vibrate, or a pulse that causes ink to be ejected from nozzle N. In this embodiment, it is assumed that the pulse PA is a pulse that causes ink to be ejected from nozzle N. Furthermore, in the printing process, instead of the pulse PA, a pulse that causes ink to be ejected from nozzle N can be supplied to line La for a unit period (TU).

[0131] The pulse PA is the waveform of the drive signal COM moving from potential V0, through a potential VLa (lower than V0), and back to potential V0. Potential V0 is the potential at the beginning and end of the pulse PA, and is the reference potential for the drive signal COM.

[0132] For example, a pulse PA has a waveform element Pa1 where the potential changes from potential V0 to potential VLa, a waveform element Pa2 where the potential is maintained at the end of waveform element Pa1 at potential VLa, and a waveform element Pa3 where the potential changes from potential VLa to potential V0. Hereinafter, waveform elements Pa1, Pa2, and Pa3 are sometimes collectively referred to as waveform element Pa.

[0133] Waveform element Pa1 is an expansion element used to displace the piezoelectric element Zb in the Z2 direction. In this expansion element, the potential change of the driving signal COM is used to drive the piezoelectric element PZ to expand the volume of the cavity CV. Therefore, in waveform element Pa1, the potential change of the driving signal COM causes the volume of the cavity CV to expand. When the volume of the cavity CV expands, as... Figure 4 As shown in Phase-2, the surface of the ink inside nozzle N is introduced in the Z2 direction, which is the opposite direction to the ejection direction. Hereinafter, the introduction of the surface of the ink inside nozzle N in the opposite direction to the ejection direction is sometimes referred to as "pull-in".

[0134] Additionally, waveform element Pa2 is a maintaining element used to maintain the position of the piezoelectric element Zb in the Z-axis direction. For example, in waveform element Pa2, the potential of the drive signal COM is maintained in order to drive the piezoelectric element PZ to maintain the volume of the cavity CV that has expanded through waveform element Pa1.

[0135] Furthermore, waveform element Pa3 is a contraction element used to displace the piezoelectric element Zb in the Z1 direction. In the contraction element, in order to drive the piezoelectric element PZ to shrink the volume of the cavity CV, a potential change in the drive signal COM is performed. Therefore, in waveform element Pa3, a potential change in the drive signal COM is performed to shrink the volume of the cavity CV. When the volume of the cavity CV shrinks, the surface of the ink in the nozzle N is pressed out in the Z1 direction, which is the ejection direction. In this embodiment, the surface of the ink in the nozzle N is pressed out in the Z1 direction by waveform element Pa3 to a degree that ink is not ejected from the nozzle N. Hereinafter, the pressing out of the surface of the ink in the nozzle N in the ejection direction is sometimes referred to as pushing.

[0136] Thus, the pulse PA is the so-called pull / push waveform. However, the waveform of the drive signal COM that prevents ink from being ejected from nozzle N is not limited to the pull / push waveform.

[0137] Additionally, for example, when the ejector section D[j] is designated as the ejector section D to be determined by the independent designation signal Sd[j], the connection state designation circuit 310 sets the connection state designation signal Qa[j] to a high level and the connection state designation signal Qs[j] to a low level during the control period TSS1. Then, during the control period TSS2, the connection state designation circuit 310 sets the connection state designation signal Qa[j] to a low level and the connection state designation signal Qs[j] to a high level. The timing of the connection state designation signal Qs[j] changing from a low level to a high level corresponds to the timing of the end of the input of the drive signal COM to the ejector section D[j] and the timing of the input of the residual vibration signal VD[j] to the signal generation unit 60.

[0138] Furthermore, when switching between control period TSS1 and control period TSS2, it is preferable that both switches SWA[j] and SWs[j] are in the ON state, and the states of each switch SWA[j] and SWs[j] switch between ON and OFF. That is, it is preferable that the timing of the connection state specifying signal Qs[j] transitioning from low to high is earlier than the timing of the connection state specifying signal Qa[j] transitioning from high to low. Additionally, it is preferable that the timing of the connection state specifying signal Qs[j] transitioning from high to low is later than the timing of the connection state specifying signal Qa[j] transitioning from low to high. In this case, when switching between control period TSS1 and control period TSS2, both switches SWA[j] and SWs[j] will not become OFF, thus suppressing [the occurrence of OFF states]. Figure 6 The potential of the wiring Ls shown changes due to switching noise and other factors.

[0139] Furthermore, it is preferable that the timing of the pulse detection period signal Pcut transitioning from high to low is earlier than the timing of the connection state specification signal Qa[j] transitioning from low to high and the timing of the connection state specification signal Qs[j] transitioning from high to low. Therefore, in this embodiment, as described above, the drive control unit 22 of the control unit 2 sets the pulse detection period signal Pcut to low at the start of pulse PlsT2. Alternatively, if the drive control unit 22 of the control unit 2 can satisfy the aforementioned transition timing, it can also set the pulse detection period signal Pcut to high at the start of pulse PlsT1 and set it to low at the start of the next pulse PlsL.

[0140] Furthermore, the timing of the signal Pcut transitioning from high to low during pulse detection is equivalent to the reset timing tep of the comparison signal CCP. Hereinafter, the timing of the signal Pcut transitioning from high to low during pulse detection is sometimes referred to as the reset timing tep.

[0141] The piezoelectric element PZ[j] of the ejection section D[j] of the object being judged is driven by the pulse PA of the drive signal COM during the control period TSS1. Specifically, the piezoelectric element PZ[j] of the ejection section D[j] of the object being judged is displaced by the pulse PA of the drive signal COM during the control period TSS1. As a result, vibration is generated in the ejection section D[j] of the object being judged. The vibration generated during the control period TSS1 also remains in the control period TSS2. Furthermore, during the control period TSS2, the potential of the upper electrode Zu[j] of the piezoelectric element PZ[j] of the ejection section D[j] of the object being judged changes according to the residual vibration generated in the ejection section D[j] of the object being judged. That is, during the control period TSS2, the potential of the upper electrode Zu of the piezoelectric element PZ of the ejection section D of the object being judged becomes a potential corresponding to the electromotive force of the piezoelectric element PZ caused by the residual vibration generated in the ejection section D of the object being judged. Furthermore, the potential of the upper electrode Zu is detected as a detection signal Vout during the control period TSS2. Thus, the change in the potential of the upper electrode Zu is detected as a detection signal Vout during the control period TSS2. As a result, the detection signal Vout is input to the detection circuit 33 as a residual vibration signal generated by the vibration remaining in the ejector section D.

[0142] The detection signal Vout, input to the detection circuit 33, is supplied to the signal generation unit 60 as a residual vibration signal VD during the control period TSS2. Therefore, during the control period TSS2, the signal generation unit 60 generates a comparison signal CP. Additionally, during the effective period TPval, the signal generation unit 60 generates a comparison signal CCP.

[0143] Next, the operation of inkjet printer 1 during the printing process will be briefly explained. Furthermore, during the printing process, the unit period TU may not be distinguished as control period TSS1 and control period TSS2. In this case, it is also possible that during the unit period TU, the period specification signal Tsig is maintained at a low level, and the pulse detection period signal Pcut is maintained at a low level.

[0144] The connection status specification signal Qs[j] is maintained at a low level during the unit period TU, regardless of whether the ejector part D[j] is specified as the ejector part D forming a point. Additionally, the connection status specification signal Qa[j] is set to a high or low level depending on whether the ejector part D[j] is specified as the ejector part D forming a point.

[0145] For example, when the ejector section D[j] is designated as the ejector section D forming a point by the independent designation signal Sd[j], the connection state designation circuit 310 sets the connection state designation signal Qa[j] to a high level during the unit period TU. Furthermore, the connection state designation signal Qa corresponding to the ejector section D that does not form a point is set to a low level during the unit period TU.

[0146] The connection state designation signal Qa[j] is set to a high level, and a drive signal COM containing a pulse that causes ink to be ejected from nozzle N is supplied from drive signal generation unit 4 to the ejection section D at the forming point. For example, the pulse that causes ink to be ejected from nozzle N is supplied to wiring La for a unit period TU. The pulse that causes ink to be ejected from nozzle N can also be a pull / push waveform, just like pulse PA. In this case, the pulse that causes ink to be ejected from nozzle N is defined such that the potential difference at the beginning and end of the contraction element, which is a waveform element that causes ink to be ejected, is greater than the potential difference at the beginning and end of the waveform element Pa3 of pulse PA. Furthermore, the pulse that causes ink to be ejected from nozzle N is not limited to a pull / push waveform. For example, the pulse that causes ink to be ejected from nozzle N can also be a pull / push / pull waveform.

[0147] The waveform elements of the pulse that causes ink to be ejected from nozzle N are defined such that a predetermined amount of ink is ejected from ejection section D[j] when an independent drive signal Vin[j] having the pulse is supplied to ejection section D[j]. In this embodiment, it is assumed that when the potential of the independent drive signal Vin[j] is high, the volume of the cavity CV provided in ejection section D[j] is smaller than when it is low. Therefore, when ejection section D[j] is driven by independent drive signal Vin[j] having a pulse that causes ink to be ejected, the ink in ejection section D[j] is ejected from nozzle N by the waveform elements of the independent drive signal Vin[j] changing from low potential to high potential.

[0148] For example, the waveform elements of the pulse that ejects ink from nozzle N are defined based on the ink ejection characteristics of the ejection section D. The ink ejection characteristics include, for example, the amount of ink ejected as droplets and the ejection velocity of the ejected droplets. Furthermore, the droplet ejection velocity varies, for example, depending on the ink viscosity. For example, the ejection velocity of droplets with a viscosity higher than a specified value is lower than the ejection velocity of droplets with a viscosity lower than a specified value. In this embodiment, the viscosity-increasing state of the ink within the ejection section D can be determined based on the amplitude Vamp indicated by the amplitude information NVamp.

[0149] In this embodiment, it is assumed that the pulse PA is a pulse that does not eject ink from the nozzle N. Therefore, the ejection state determination process can be performed even when the head unit 3 is not located on the ink discharge receiving section 80. For example, the ejection state determination process can be performed between passes while the head unit 3 is moving along the X-axis and printing is performed in one pass. Alternatively, the ejection state determination process can be performed between printing tasks based on one print data IMG and printing tasks based on other print data IMGs. Or, the ejection state determination process can be performed during maintenance processing.

[0150] Furthermore, the operation of inkjet printer 1 is not limited to Figure 8 The example shown. For example, the pulse PA can be a pulse that causes ink to be ejected from the nozzle N. In this case, the drive signal COM containing the pulse PA can be used in both the printing process and the ejection state determination process. However, if the pulse PA used in the ejection state determination process is a pulse that causes ink to be ejected from the nozzle N, the ejection state determination process is preferably performed, for example, when the head unit 3 is located on the ink discharge receiving section 80.

[0151] Alternatively, for example, when the control unit 2 performs the ejection state determination process, it may also output a duration-defined signal Tsig consisting only of pulse PlsT1 from pulses PlsT1 and PlsT2. In this case, the drive control unit 22 of the control unit 2 may, for example, set the pulse detection period signal Pcut to a high level at the start or end of pulse PlsT1 and set it to a low level at the start of the next pulse PlsL in order to satisfy the aforementioned transition timing.

[0152] Additionally, for example, in Figure 8 The example shown depicts a single drive signal COM, but the invention is not limited to this approach. For instance, multiple drive signals COM, including a drive signal COM that prevents ink from being ejected from nozzle N and a drive signal COM that allows ink to be ejected from nozzle N, can also be used. In this case, during the printing process, a pulse PA that prevents ink ejection can be used to prevent ink thickening. Furthermore, the drive signal COM that allows ink to be ejected from nozzle N can also consist of multiple pulses used to form dots of different sizes ejected from nozzle N.

[0153] Next, refer to Figure 9 The signals supplied to the signal generation unit 60 and the signals generated by the signal generation unit 60 will be explained.

[0154] Figure 9 This is a timing diagram illustrating an example of the operation of the signal generation unit 60. Furthermore, in Figure 9 In the diagram, the comparison signal CCP is shown as a solid line when the inspection mode is the first inspection mode, and the comparison signal CCP is shown as a dashed line when the inspection mode is the second inspection mode. Figure 9 In this section, the comparison signal CCP is explained, focusing on the case where the first inspection mode is used.

[0155] Figure 9 The time t0 indicates the timing at which the supply of the residual vibration signal VD to the signal generation unit 60 begins. The timing at which the supply of the residual vibration signal VD to the signal generation unit 60 begins is, for example,... Figure 8 The connection status indicator signal Qs[j] transitions from low to high at a specific timing. In the first check mode, the connection status indicator signal Qs[j] transitions from high to low, for example, between time t15 and time t16. However, in... Figure 9 For ease of understanding, it is assumed that regardless of the inspection mode, from time t0 to time t45, the connection state specification signal Qs[j] is maintained at a high level to explain the comparison signal CCP, etc.

[0156] exist Figure 9 In this context, we assume that the potential of the residual vibration signal VD at time t0 is lower than the threshold potential VthC corresponding to the center level of the residual vibration signal VD's amplitude, and that the first peak PK1 of the residual vibration signal VD is the peak where the potential of the residual vibration signal VD becomes a maximum. Therefore, in Figure 9 In the example shown, the second peak PK2 of the residual vibration signal VD is the peak where the potential of the residual vibration signal VD reaches a minimum, and the third peak PK3 of the residual vibration signal VD is the peak where the potential of the residual vibration signal VD reaches a maximum. Hereinafter, peaks PK1, PK2, and PK3 of the residual vibration signal VD, as well as all other peaks of the residual vibration signal VD, are sometimes collectively referred to as peak PK.

[0157] For example, the potential of the residual vibration signal VD increases with time from time t0 to time t15, and decreases with time from time t15 to time t25. Furthermore, the potential of the residual vibration signal VD increases with time from time t25 to time t35, and decreases with time from time t35 to time t45.

[0158] First, we assume that the connection state specification signal Qs[j] is kept high from time t0 to time t45 to explain the comparison signals CPC, CP1, and CP2.

[0159] For example, at time t10, which is later than time t0, the potential of the residual vibration signal VD reaches the threshold potential VthC. Therefore, the comparator circuit 620 causes the comparator signal CPc to change from low to high at time t10. Hereinafter, the timing of the change from low to high of the comparator signal CPc is sometimes referred to as timing tsc. For example, in Figure 9 In this context, time t10 corresponds to time tsc.

[0160] Furthermore, at time t12, which is later than time t10, the potential of the residual vibration signal VD reaches a threshold potential Vth2 that is higher than the threshold potential VthC. Therefore, the comparator circuit 622 causes the comparator signal CP2 to change from low to high at time t12. Hereinafter, the timing of the change from low to high of the comparator signal CP2 is sometimes referred to as timing ts2. For example, in Figure 9 In this context, time t12 corresponds to time ts2. Additionally, time tsc, ts1, and ts2 are sometimes collectively referred to as time ts.

[0161] Furthermore, at time t14, which is later than time t12, the potential of the residual vibration signal VD reaches a threshold potential Vth1 that is higher than the threshold potential Vth2. Therefore, the comparator circuit 621 causes the comparator signal CP1 to change from low to high at time t14. Hereinafter, the timing of the change from low to high of the comparator signal CP1 is sometimes referred to as timing ts1. For example, in Figure 9 In this context, time t14 corresponds to time ts1.

[0162] Furthermore, at time t15, which is later than time t14, the potential of the residual vibration signal VD reaches its peak from the threshold potential Vth1. Therefore, the potential of the residual vibration signal VD begins to decrease from time t15.

[0163] Furthermore, at time t16, which is later than time t15, the potential of the residual vibration signal VD reaches the threshold potential Vth1. Therefore, the comparator circuit 621 causes the comparator signal CP1 to change from high level to low level at time t16.

[0164] Furthermore, at time t18, which is later than time t16, the potential of the residual vibration signal VD reaches the threshold potential Vth2. Therefore, the comparator circuit 622 causes the comparator signal CP2 to change from high level to low level at time t18.

[0165] Furthermore, at time t20, which is later than time t18, the potential of the residual vibration signal VD reaches the threshold potential VthC. Therefore, the comparator circuit 620 changes the comparator signal CPc from high level to low level at time t20.

[0166] Thus, the comparator circuit 620 generates a comparator signal CPc indicating whether the potential of the residual vibration signal VD is above the threshold potential VthC, the comparator circuit 621 generates a comparator signal CP1 indicating whether the potential of the residual vibration signal VD is above the threshold potential Vth1, and the comparator circuit 622 generates a comparator signal CP2 indicating whether the potential of the residual vibration signal VD is above the threshold potential Vth2.

[0167] Next, the comparison signals CCPc, CCP1, and CCP2 will be explained.

[0168] The comparison signal CCP is a signal that resets the comparison signal CP to a low level according to the reset timing tep specified by the pulse detection period signal Pcut. Furthermore, in the first check mode, the reset timing tep for the pulse detection period signal Pcut to transition from high to low is preferably earlier than the timing for the comparison signal CCP1 to transition from high to low. Figure 9 In the example shown, during pulse detection, the signal Pcut transitions from high to low at time t15, corresponding to the timing of the first peak PK1 of the residual vibration signal VD. Therefore, in Figure 9 In the example shown, time t15 corresponds to the reset time tep.

[0169] For example, the comparison signal CCPc transitions from low to high according to the timing tsc, which indicates that the comparison signal CCPc has transitioned from low to high, and the reset timing tep, which indicates that the pulse detection signal Pcut has transitioned from high to low, transitions from high to low. Therefore, the period WCc during which the comparison signal CCPc is high is the period from timing tsc to reset timing tep, and the duration TCc of WCc corresponds to the elapsed time from timing tsc to reset timing tep.

[0170] Additionally, for example, the comparison signal CCP2 transitions from low to high according to timing ts2, which is when the comparison signal CP2 transitions from low to high, and from high to low according to reset timing tep. Therefore, the period WC2 during which the comparison signal CCP2 is high is the period from timing ts2 to reset timing tep, and the duration TC2 of period WC2 corresponds to the elapsed time from timing ts2 to reset timing tep.

[0171] Additionally, for example, the comparison signal CCP1 transitions from low to high according to timing ts1, which causes CCP1 to transition from low to high, and from high to low according to reset timing tep. Therefore, the period WC1 during which the comparison signal CCP1 is high is the period from timing ts1 to reset timing tep, and the duration TC1 of period WC1 corresponds to the elapsed time from timing ts1 to reset timing tep.

[0172] Thus, in the first inspection mode, comparison signals CCPc, CCP1, and CCP2 are generated corresponding to the first portion of the signal within the first period TPP1 of the residual vibration signal VD from time t10 to time t15. Figure 9 In the example shown, the portion of the residual vibration signal VD from time t10 to time t15 corresponds to the first portion of the signal. Furthermore, the first period TPP1 preferably begins before a first time has elapsed since the residual vibration signal VD was input to the signal generation unit 60. This first time is, for example, a time shorter than one-quarter of the period of the residual vibration signal VD. In this case, it is possible to suppress the inspection time from becoming longer. For example, it is possible to suppress the waiting time from the input of the residual vibration signal VD to the signal generation unit 60 to the start of the generation of the comparison signal CCP from becoming longer. Furthermore, Figure 9 The comparison signals CCPc, CCP1, and CCP2, shown by solid lines, are an example of the "status check signal" and the "first check mode signal".

[0173] Here, the amplitude Vamp of the peak PK1 of the residual vibration signal VD is equivalent to the amplitude VPK of the peak VpK. Figure 7 As explained, the residual vibration signal VD is approximated as a sine wave by equation (1) or (2). For example, when the elapsed time from time t10 is set as "t", the angular velocity is set as "ω", and the potential difference between the potential of the residual vibration signal VD at time t and the threshold potential VthC is set as "VE", the potential difference VE is expressed using the amplitude VPK and by equation (3). In the following equations, the symbol "・" indicating multiplication is used appropriately.

[0174] VE=VPK・sin(ωt)…(3)

[0175] In addition, the time length TCc of WCc during the period when the comparison signal CCPc is high corresponds to one-quarter of the period of the residual vibration signal VD. Therefore, the angular velocity ω is expressed using the time length TCc and by equation (4).

[0176] ω=π / (2・TCc)…(4)

[0177] In addition, the elapsed time from time t10 to time t14 is represented by the formula “TCc-TC1”, which is the time length TCc minus the time length TC1, and the elapsed time from time t10 to time t12 is represented by the formula “TCc-TC2”, which is the time length TCc minus the time length TC2.

[0178] Therefore, the potential difference VE1 between the residual vibration signal VD at time t14 and the threshold potential VthC is expressed by equation (5) using time lengths TCc and TC1. In addition, the potential difference VE2 between the residual vibration signal VD at time t12 and the threshold potential VthC is expressed by equation (6) using time lengths TCc and TC2.

[0179] VE1=VPK・sin(π・(TCc-TC1) / (2・TCc))…(5)

[0180] VE2=VPK・sin(π・(TCc-TC2) / (2・TCc))…(6)

[0181] In addition, the amplitude VPK transforms equation (5) and is represented by equation (7). Alternatively, the amplitude VPK transforms equation (6) and is represented by equation (8).

[0182] VPK=VE1 / (sin((π / 2)・(1-TC1 / TCc)))…(7)

[0183] VPK=VE2 / (sin((π / 2)・(1-TC2 / TCc)))…(8)

[0184] The potential at time t14 of the residual vibration signal VD is the threshold potential Vth1. Therefore, the potential difference VE1 is the value obtained by subtracting the threshold potential VthC from the threshold potential Vth1. Thus, by substituting the equation "Vth1-VthC" (subtracting the threshold potential VthC from Vth1) into the potential difference VE1 in equation (7), and substituting the amplitude Vamp into the amplitude VPK in equation (7), it is possible to derive the value of the residual vibration signal VD at time t14. Figure 7 Equation (1) is explained in the text. Furthermore, the potential at time t12 of the residual vibration signal VD is the threshold potential Vth2, therefore the potential difference VE2 becomes the value obtained by subtracting the threshold potential VthC from the threshold potential Vth2. Thus, by substituting the equation "Vth2-VthC" (subtracting the threshold potential VthC from Vth2) into the potential difference VE2 in equation (8), and substituting the amplitude Vamp into the amplitude VPK in equation (8), it is possible to derive the value of... Figure 7 Equation (2) is explained in the text.

[0185] Details are in Figure 10The following will be explained later, but the amplitude Vamp calculated from equation (1) is adjusted by adjusting at least one of the potential difference between the threshold potential VthC and the threshold potential Vth1, and the ratio of the time length TC1 to the time length TCc, i.e., the time ratio. By adjusting the amplitude Vamp calculated from equation (1), the difference between the amplitude Vamp calculated from equation (1) in the normal state of the ejection section D and the amplitude Vamp calculated from equation (1) in the abnormal state of the ejection section D can be adjusted. Therefore, by adjusting the amplitude Vamp calculated from equation (1), the sensitivity when determining the state of the ejection section D can be adjusted. Similarly, by adjusting the amplitude Vamp calculated from equation (2), the sensitivity when determining the state of the ejection section D can be adjusted. In this embodiment, the sensitivity when determining the state of the ejection section D can be adjusted by adjusting the amplitude Vamp calculated from equation (1), and the sensitivity when determining the state of the ejection section D can also be adjusted by adjusting the amplitude Vamp calculated from equation (2).

[0186] Next, the comparison signal CCP, etc., in the case of the second inspection mode will be briefly explained. In the second inspection mode, the amplitude of the peak PK3 of the residual vibration signal VD is used instead of the amplitude of the peak PK1 of the residual vibration signal VD to determine the state of the ejection section D. Therefore, for example, the comparison signal CP from time t0 to time t25 is not used to determine the state of the ejection section D. Therefore, in the second inspection mode, the mask signal MSK, for example, is like... Figure 9 As shown by the dashed line, the mask signal MSK is maintained at a high level from time t0 to time t25, and then transitions from high to low at time t25. Furthermore, the mask signal MSK is maintained at a low level, for example, from time t25 to time t45. During the period when the mask signal MSK is high, i.e., from time t0 to time t25, the comparison signal CCP is maintained at a low level regardless of the level of the comparison signal CP.

[0187] Additionally, in the second inspection mode, during pulse detection, the signal Pcut, for example, is like... Figure 9 As shown by the dashed line, it is maintained at a high level before time t45, and transitions from a high level to a low level at time t45. Therefore, in the second check mode, time t45 corresponds to the reset timing tep.

[0188] As described above, the potential of the residual vibration signal VD increases with time from time t25 to time t35, and decreases with time from time t35 to time t45.

[0189] For example, at time t30, which is later than time t25, the potential of the residual vibration signal VD reaches the threshold potential VthC. Therefore, the comparator circuit 620 changes the comparator signal CPc from low to high at time t30.

[0190] Furthermore, at time t32, which is later than time t30, the potential of the residual vibration signal VD reaches a threshold potential Vth2 that is higher than the threshold potential VthC. Therefore, the comparator circuit 622 causes the comparator signal CP2 to change from low level to high level at time t32.

[0191] Furthermore, at time t34, which is later than time t32, the potential of the residual vibration signal VD reaches a threshold potential Vth1 that is higher than the threshold potential Vth2. Therefore, the comparator circuit 621 causes the comparator signal CP1 to change from a low level to a high level at time t34.

[0192] Furthermore, at time t35, which is later than time t34, the potential of the residual vibration signal VD reaches its peak from the threshold potential Vth1. Therefore, the potential of the residual vibration signal VD begins to decrease from time t35.

[0193] Then, at time t36, which is later than time t35, the potential of the residual vibration signal VD reaches the threshold potential Vth1. Therefore, the comparator circuit 621 causes the comparator signal CP1 to change from high level to low level at time t36.

[0194] Furthermore, at time t38, which is later than time t36, the potential of the residual vibration signal VD reaches the threshold potential Vth2. Therefore, the comparator circuit 622 causes the comparator signal CP2 to change from high level to low level at time t38.

[0195] Furthermore, at time t40, which is later than time t38, the potential of the residual vibration signal VD reaches the threshold potential VthC. Therefore, the comparator circuit 620 causes the comparator signal CPc to change from a high level to a low level at time t40.

[0196] In the second check mode, time t45, corresponding to the reset timing tep, is a time later than time t40. Therefore, for example, the comparison signal CCPc, generated by the logical product of the inverted mask signal MSK, the pulse detection period signal Pcut, and the comparison signal CPC, is used... Figure 9 As shown by the dashed line, it becomes the same signal as the comparison signal CPC. Additionally, the comparison signal CCP1, generated by the logical product of the inverted mask signal MSK, the pulse detection period signal Pcut, and the comparison signal CP1, is as follows: Figure 9As shown by the dashed line, it becomes the same signal as the comparison signal CP1. Furthermore, the comparison signal CCP2, generated by the logical product of the inverted mask signal MSK, the pulse detection period signal Pcut, and the comparison signal CP2, is as follows: Figure 9 As shown by the dashed line, it becomes the same signal as the comparison signal CP2.

[0197] Therefore, in the second inspection mode, the duration Toc of the period when the comparison signal CPc is high (WOc) becomes the duration TCc of the period when the comparison signal CCPc is high (WCc). Similarly, the duration TO1 of the period when the comparison signal CP1 is high (WO1) becomes the duration TC1 of the period when the comparison signal CCP1 is high (WC1). Furthermore, the duration TO2 of the period when the comparison signal CP2 is high (WO2) becomes the duration TC2 of the period when the comparison signal CCP2 is high (WC2). Additionally, in the second inspection mode, the amplitude Vamp of the residual vibration signal VD is determined by approximating the waveform of the residual vibration signal VD as a sine wave. Figure 7 The calculation is performed using formula (1) or formula (2) as described in the text.

[0198] Thus, in the second inspection mode, comparison signals CCPc, CCP1, and CCP2 are generated corresponding to the second portion of the signal in the second period TPP2 of the residual vibration signal VD from time t30 to time t40. Therefore, in the second inspection mode, the period of the residual vibration signal VD can be determined based on the comparison signal CCPc. In this case, multiple state anomalies, including the viscosity increase state of the ink within the ejection section D, can be determined based on the amplitude Vamp and period of the residual vibration signal VD. Figure 9 In the example shown, the portion of the residual vibration signal VD from time t30 to time t40 corresponds to the second part of the signal. Figure 9 The dashed lines showing the comparison signals CCPc, CCP1, and CCP2 are an example of the "status check signal" and the "second check mode signal".

[0199] Here, the second period TPP2 is a period that follows the first period TPP1, but is longer than the first period TPP1. Therefore, in the second inspection mode, in Figure 8When switching between the control period TSS1 and control period TSS2, the influence of noise during the determination of the state of the ejector section D can be suppressed even when the residual vibration signal VD is superimposed with noise. On the other hand, in the first inspection mode, the comparison signals CCPc, CCP1, and CCP2 used to determine the state of the ejector section D are generated based on the first portion of the signal within the first period TPP1, which is shorter than the second period TPP2 in the residual vibration signal VD. Therefore, in the first inspection mode, the unit period TU can be shortened compared to the second inspection mode, thus shortening the inspection time. For example, the first period TPP1 is less than one-quarter of the period of the residual vibration signal VD, and the second period TPP2 is more than one-half of the period of the residual vibration signal VD. That is, in the second inspection mode, the comparison signal CCP within the second period TPP2, which is more than half of the period of the residual vibration signal VD, can be used to calculate the amplitude Vamp, but in the first inspection mode, the comparison signal CCP within the first period TPP1, which is less than one-quarter of the period of the residual vibration signal VD, can be used to calculate the amplitude Vamp.

[0200] In addition, each comparison signal CCP can also be generated by a method other than the method of operating on the logical product of the comparison signal CP corresponding to the comparison signal CCP, the inverted signal of the mask signal MSK, and the pulse detection period signal Pcut.

[0201] For example, in the first check mode, the output signal can be changed from low to high when the comparison signal CPC changes from low to high, and the comparison signal CCPc can be generated by a latch circuit that resets the output signal to low when the signal Pcut changes from high to low during pulse detection. Similarly, the comparison signal CCP1 can be generated by a latch circuit that resets the output signal to low when the comparison signal CP1 changes from low to high, and the comparison signal CCP1 can be generated by a latch circuit that resets the output signal to low when the signal Pcut changes from high to low during pulse detection. Alternatively, the output signal can be changed from low to high when the comparison signal CP2 changes from low to high, and the comparison signal CCP2 can be generated by a latch circuit that resets the output signal to low when the signal Pcut changes from high to low during pulse detection. As described above, in the scheme of generating the comparison signal CCP by a latch circuit, for example, the reset timing tep can be set to a timing later than the timing of the comparison signal CP1 changing from high to low. In addition, in a scheme that generates a comparison signal CCP by means of a latching circuit, for example, the shielding timing that can shield the signal path of the residual vibration signal VD from the ejection section D to the signal generation section 60 is set earlier than the reset timing tep.

[0202] Alternatively, for example, in the second check mode, the comparison signal CPc can also be output from the adjustment circuit 630 to the determination circuit 670 as the comparison signal CCPc. Similarly, the comparison signal CP1 can be output from the adjustment circuit 631 to the determination circuit 671 as the comparison signal CCP1, and the comparison signal CP2 can be output from the adjustment circuit 632 to the determination circuit 672 as the comparison signal CCP2.

[0203] Alternatively, for example, the pulse detection period signal Pcut and the mask signal MSK can also be generated by the connection state specifying circuit 310 of the switching circuit 31. Specifically, the connection state specifying circuit 310 can also generate the pulse detection period signal Pcut and the mask signal MSK based on at least a portion of the printed signal SI, the latch signal LAT, and the period specification signal Tsig.

[0204] In addition, for example, Figure 9 The signal shown, which corresponds to the logical product of the pulse detection period signal Pcut and the inverted mask signal MSK, can also be used as a signal that combines the pulse detection period signal Pcut and the mask signal MSK.

[0205] Additionally, for example, in the second inspection mode, the amplitude of the peak PK2 of the residual vibration signal VD can also be used in determining the state of the ejection section D. In this case, the comparison circuits 620, 621, and 622 can operate with the pulse detection period signal Pcut and the mask signal MSK as follows.

[0206] For example, comparator circuit 620 generates a comparator signal CPc that is high when the potential of the residual vibration signal VD is below the threshold potential VthC, and low when the potential of the residual vibration signal VD is above the threshold potential VthC. Comparator circuit 621 generates a comparator signal CP1 that is high when the potential of the residual vibration signal VD is below the threshold potential Vthm1, and low when the potential of the residual vibration signal VD is above the threshold potential Vthm1. Comparator circuit 622 generates a comparator signal CP2 that is high when the potential of the residual vibration signal VD is below the threshold potential Vthm2, and low when the potential of the residual vibration signal VD is above the threshold potential Vthm2. Additionally, the mask signal MSK is maintained at a high level from time t0 to time t15, and transitions from high to low at time t15. Furthermore, the mask signal MSK is maintained at a low level, for example, from time t25 to time t45. Additionally, during pulse detection, the signal Pcut is maintained at a high level before time t35, and transitions from high to low at time t35. Furthermore, the threshold potential Vthm2 is a potential lower than the threshold potential VthC, and the threshold potential Vthm1 is a potential lower than the threshold potential Vthm2.

[0207] Additionally, for example, in the second inspection mode, the amplitude of the peak PK1 of the residual vibration signal VD can also be used to determine the state of the ejection section D. In this case, for example, the signal Pcut during the pulse detection period of the second inspection mode can be maintained at a high level before time t25, and then transition from a high level to a low level at time t25. Furthermore, in the second inspection mode, when the amplitude of the peak PK1 of the residual vibration signal VD is used to determine the state of the ejection section D, the mask signal MSK can be omitted.

[0208] Furthermore, in the first inspection mode, the time ratios of the time length TC1 to the time length TCc and the time ratios of the time length TC2 to the time length TCc can be adjusted by adjusting the reset timing tep. In this case, the amplitude Vamp calculated from equation (1) can be adjusted, thus adjusting the sensitivity when determining the state of the ejection section D. That is, in the first inspection mode, the sensitivity when determining the state of the ejection section D can also be adjusted by adjusting the reset timing tep.

[0209] Next, refer to Figures 10 to 12 The adjustment of sensitivity when determining the state of the ejection section D using the first inspection mode is explained. Furthermore, in Figures 10 to 12The example illustrates the comparison between the potential of the residual vibration signal VD and the threshold potential Vth1. When comparing the potential of the residual vibration signal VD and the threshold potential Vth2, the method also involves rereading elements related to the threshold potential Vth1 as elements related to the threshold potential Vth2. Figures 10 to 12 Explanation

[0210] Figure 10 This is an explanatory diagram used to illustrate the relationship between the residual vibration signal VD, the reset timing tep, and the comparison signal CCP. Figure 10 The diagram shows the signal Pcut during pulse detection, the residual vibration signal VD of a normal nozzle, the comparison signals CCPc and CCP1 of a normal nozzle, the residual vibration signal VD of an abnormal nozzle, and the comparison signals CCPc and CCP1 of an abnormal nozzle. A normal nozzle indicates that the state of the ejection section D is normal, while an abnormal nozzle indicates that the state of the ejection section D is abnormal.

[0211] In addition, Figure 10 In the coordinate graph of the residual vibration signal VD, the vertical axis shows the potential difference between the voltage [V] and the threshold potential VthC, which is based on the threshold potential VthC, and the horizontal axis shows the elapsed time [μs] from the reference timing tref. Furthermore, the unit [μs] represents microseconds. Additionally, in... Figure 10 In this context, the reference timing tref is the timing at which the residual vibration signal VD of a normal nozzle rises from a potential lower than the threshold potential VthC to the threshold potential VthC. Additionally, in... Figure 10 In this context, we assume the potential difference between the threshold potential VthC and the threshold potential Vth1 is 0.5V. Furthermore, in... Figure 10 In this context, we assume the amplitude VPK of the residual vibration signal VD from a normal nozzle is 1.0V, the amplitude VPK of the residual vibration signal VD from an abnormal nozzle is 0.9V, and the time TPH corresponding to the phase difference between the residual vibration signals VD from the normal nozzle and the abnormal nozzle is 0.5μs. Furthermore, in... Figure 10 In this case, we assume that the period of the residual vibration signal VD of the normal nozzle is the same as the period of the residual vibration signal VD of the abnormal nozzle, and one-quarter of the period is 2.0 μs. Figure 10 The dashed line in the coordinate graph of the residual vibration signal VD shows the inclination in the threshold potential Vth1 of the residual vibration signal VD of a normal nozzle. Figure 10 In this case, it is assumed that the tilt in the threshold potential Vth1 of the residual vibration signal VD is almost unchanged in normal and abnormal nozzles.

[0212] exist Figure 10The diagram shows the comparison signals CCPc and CCP1 when the reset timing tep, during the pulse detection period, is the time when the signal Pcut transitions from high to low, and the timing is 2.0 μs after the reference timing tref. Additionally, in... Figure 10 In the image, a dashed line shows an example of the adjusted reset timing tep.

[0213] In both normal and abnormal nozzles, even if the reset timing tep is adjusted, the timing tsc for the comparison signal CCPc to transition from low to high will not be adjusted. In contrast, the timing for the comparison signal CCPc to transition from high to low is adjusted to the same timing as the reset timing tep in both normal and abnormal nozzles. Therefore, in both normal and abnormal nozzles, the duration TCc of the period WCc during which the comparison signal CCPc is high is adjusted by adjusting the reset timing tep.

[0214] Furthermore, in both normal and abnormal nozzles, even if the reset timing tep is adjusted, the timing ts1 of the comparison signal CCP1 transitioning from low to high will not be adjusted. In contrast, the timing of the comparison signal CCP1 transitioning from high to low is adjusted to the same timing as the reset timing tep in both normal and abnormal nozzles. Therefore, in both normal and abnormal nozzles, the duration TC1 of the period WC1 during which the comparison signal CCP1 is high is adjusted by adjusting the reset timing tep.

[0215] Next, refer to Figure 11 The relationship between the adjustment of the reset timing tep and the amplitude Vamp calculated based on the time lengths TCc and TC1 after the reset timing tep is adjusted is explained.

[0216] Figure 11 This is an explanatory diagram illustrating the relationship between the reset timing tep and the amplitude Vamp calculated based on the time lengths TCc and TC1. Figure 11 The adjusted waveform shows the time lengths TCc and TC1 adjusted by the reset timing tep from the time lengths TCc and TC1. Figure 7 The amplitude Vamp is calculated by equation (1) as described in the diagram. That is, the adjusted waveform is considered as a virtual waveform of the residual vibration signal VD with an amplitude Vamp calculated based on the time lengths TCc and TC1, and is not limited to becoming the same waveform as the residual vibration signal VD actually output from the detection circuit 33.

[0217] exist Figure 11In the coordinate graphs of the residual vibration signal VD and the adjusted waveform, the vertical axis shows the potential difference between the voltage [V] and the threshold potential VthC, which is based on the threshold potential VthC, and the horizontal axis shows the elapsed time [μs] from the reference timing tref. Furthermore, in Figure 11 Similarly, the reference timing tref is the timing when the residual vibration signal VD of the normal nozzle rises from a potential lower than the threshold potential VthC to the threshold potential VthC. The potential difference between the threshold potential VthC and the threshold potential Vth1 is 0.5V.

[0218] in addition, Figure 11 The residual vibration signal VD of the normal nozzle and the residual vibration signal VD of the abnormal nozzle are shown in the figure. Figure 10 The residual vibration signal VD of the normal nozzle and the residual vibration signal VD of the abnormal nozzle are the same as described. For example, the amplitude VPK of the residual vibration signal VD of the normal nozzle is 1.0V, and the amplitude VPK of the residual vibration signal VD of the abnormal nozzle is 0.9V. In addition, the time TPH corresponding to the phase difference between the residual vibration signal VD of the normal nozzle and the residual vibration signal VD of the abnormal nozzle is 0.5μs. In addition, one-quarter of the period of the residual vibration signal VD of the normal nozzle and the residual vibration signal VD of the abnormal nozzle is 2.0μs. Therefore, the residual vibration signal VD of the normal nozzle becomes peak PK1 after 2.0μs of timing from the reference timing tref, and the residual vibration signal VD of the abnormal nozzle becomes peak PK1 after 2.5μs of timing from the reference timing tref.

[0219] Hereinafter, the timing of the residual vibration signal VD becoming the peak PK1 is sometimes referred to as the peak timing of the residual vibration signal VD. Figure 10 In the example shown, the peak timing of the residual vibration signal VD corresponds to the timing when the potential of the residual vibration signal VD reaches the threshold potential VthC from a potential lower than the threshold potential VthC, which takes one-quarter of the period of the residual vibration signal VD.

[0220] exist Figure 11 The diagram shows four adjustment waveforms corresponding to the four reset timings tep in each normal and abnormal nozzle. Figure 11 The four reset timings tep shown are 1.5μs, 2.0μs, 2.5μs, and 3.0μs elapsed from the reference timing tref, respectively.

[0221] like Figure 11 As shown, in both normal and abnormal nozzles, the amplitude Vamp of the adjustment waveform increases when the time from the reference timing tref to the reset timing tep is longer compared to when the time from the reference timing tref to the reset timing tep is shorter.

[0222] For example, the peak timing of the residual vibration signal VD of a normal nozzle, as described above, is 2.0 μs after the reference timing tref. Therefore, in a normal nozzle, when the reset timing tep is 2.0 μs after the reference timing tref, the amplitude Vamp of the adjustment waveform becomes 1.0V, which matches the amplitude VPK of the residual vibration signal VD. Furthermore, when the reset timing tep is 1.5 μs after the reference timing tref, the amplitude Vamp of the adjustment waveform becomes approximately 0.8V, which is smaller than the amplitude VPK of the residual vibration signal VD. Additionally, when the reset timing tep is 2.5 μs after the reference timing tref, the amplitude Vamp of the adjustment waveform becomes approximately 1.2V, which is larger than the amplitude VPK of the residual vibration signal VD. Furthermore, when the reset timing tep is 3.0 μs elapsed from the reference timing tref, the amplitude Vamp of the adjustment waveform becomes 1.5V, which is larger than the amplitude VPK of the residual vibration signal VD. Additionally, the amplitude Vamp of the adjustment waveform when the reset timing tep is 3.0 μs elapsed from the reference timing tref is larger than the amplitude Vamp of the adjustment waveform when the reset timing tep is 2.5 μs elapsed from the reference timing tref.

[0223] Furthermore, for example, the peak timing of the residual vibration signal VD from the abnormal nozzle, as described above, is 2.5 μs after the reference timing tref. Therefore, in the abnormal nozzle, when the reset timing tep is 2.5 μs after the reference timing tref, the amplitude Vamp of the adjusted waveform becomes 0.9V, which is consistent with the amplitude VPK of the residual vibration signal VD. Furthermore, when the reset timing tep is 2.0 μs after the reference timing tref, the amplitude Vamp of the adjusted waveform becomes approximately 0.7V, which is smaller than the amplitude VPK of the residual vibration signal VD. Furthermore, when the reset timing tep is 1.5 μs after the reference timing tref, the amplitude Vamp of the adjusted waveform becomes approximately 0.5V, which is smaller than the amplitude VPK of the residual vibration signal VD. Furthermore, when the reset timing tep is 1.5 μs elapsed from the reference timing tref, the amplitude Vamp of the adjusted waveform is smaller compared to the case where the reset timing tep is 2.0 μs elapsed from the reference timing tref. Additionally, when the reset timing tep is 3.0 μs elapsed from the reference timing tref, the amplitude Vamp of the adjusted waveform becomes approximately 1.1V, which is larger than the amplitude VPK of the residual vibration signal VD.

[0224] During the periods when comparison signal CCPc is high (WCc) and comparison signal CCP1 is high (WC1), one end of each is fixed by the reset timing tep. Therefore, the amplitude Vamp calculated based on the time lengths TCc and TC1 contains information about both the change in amplitude VPK and the change in phase. For example, the amplitude Vamp of the adjustment waveform of an abnormal nozzle contains information about the changes in both amplitude VPK and phase of the residual vibration signal VD of the abnormal nozzle relative to the residual vibration signal VD of a normal nozzle. In such cases... Figure 11 In the example shown, when the reset timing tep is 2.0 μs elapsed from the reference timing tref, the amplitude Vamp of the adjustment waveform of the abnormal nozzle is smaller than the amplitude VPK of the residual vibration signal VD of the abnormal nozzle, as described above. Thus, in the first inspection mode, the change in phase difference can be derived as a change in amplitude Vamp, and therefore the parameter for determining the state of the ejection section D can be set from two modes—amplitude VPK and phase—to a single mode—the amplitude Vamp of the adjustment waveform. This simplifies the ejection state determination process in the first inspection mode.

[0225] Furthermore, in the first inspection mode, the amplitude Vamp of the adjustment waveform of the abnormal nozzle contains information on both the change in amplitude VPK and the change in phase, thus suppressing the decrease in accuracy of determining whether the state of the ejection section D is normal. For example, in the first inspection mode, even when the amplitude difference DVR or phase difference between the residual vibration signal VD of the normal nozzle and the residual vibration signal VD of the abnormal nozzle is small, the decrease in accuracy of determining whether the state of the ejection section D is normal can also be suppressed.

[0226] Specifically, in Figure 11In the example shown, the amplitude difference DVR between the residual vibration signal VD of the normal nozzle and the residual vibration signal VD of the abnormal nozzle is 0.1V. In contrast, for example, when the reset timing tep is 2.0μs elapsed from the reference timing tref, the amplitude difference DV1 between the adjustment waveform of the normal nozzle and the adjustment waveform of the abnormal nozzle is approximately 0.3V, which is larger than 0.1V. That is, when the reset timing tep is 2.0μs elapsed from the reference timing tref, the amplitude difference DV1 between the adjustment waveform of the normal nozzle and the adjustment waveform of the abnormal nozzle is larger than the amplitude difference DVR between the residual vibration signals VD of the normal nozzle and the abnormal nozzle. In this case, it is possible to determine whether the state of the ejection section D is normal based on the amplitude difference DV1, which is larger than the amplitude difference DVR between the residual vibration signals VD of the normal nozzle and the abnormal nozzle. Therefore, in the first inspection mode, compared to the case where the state of the ejector section D is determined based on the amplitude difference DVR between the residual vibration signal VD of a normal nozzle and the residual vibration signal VD of an abnormal nozzle, the determination circuit 69 can determine whether the state of the ejector section D is normal with good accuracy. For example, if the amplitude Vamp calculated by the amplitude calculation circuit 68 is smaller than a predetermined threshold amplitude based on the amplitude Vamp of the adjustment waveform of a normal nozzle, the determination circuit 69 can also determine that the state of the ejector section D is abnormal.

[0227] Furthermore, for example, when the reset timing tep is 3.0 μs elapsed from the reference timing tref, the amplitude difference DV2 between the adjustment waveform of the normal nozzle and the adjustment waveform of the abnormal nozzle is approximately 0.4V, which is larger than 0.3V. That is, the amplitude difference DV2 is larger than the amplitude difference DV1. Hereinafter, the amplitude differences DV2 and DV1 will sometimes be collectively referred to as the amplitude difference DV. Moreover, hereafter, the amplitude difference between the adjustment waveform of the normal nozzle and the adjustment waveform of the abnormal nozzle will sometimes be referred to as the amplitude difference DV.

[0228] exist Figure 11 In the example shown, the amplitude difference DV between the adjustment waveform of a normal nozzle and the adjustment waveform of an abnormal nozzle is larger when the time from the reference timing tref to the reset timing tep is longer than when the time from the reference timing tref to the reset timing tep is shorter.

[0229] In this way, in the first inspection mode, the sensitivity when detecting changes in the phase of the residual vibration signal VD can be adjusted by using the reset timing tep, so the sensitivity when determining the state of the ejection section D can be set according to the application.

[0230] Next, refer to Figure 12 The relationship between reset timing tep, amplitude Vamp, and amplitude change rate is explained.

[0231] Figure 12 This is an explanatory diagram used to illustrate the relationship between reset timing tep, amplitude Vamp, and amplitude change rate. Figure 12 One side of the vertical axis shows the voltage [V] of the amplitude Vamp relative to the threshold potential VthC, and the other side shows the amplitude change rate [%]. The horizontal axis shows the time [μs] of the reset timing tep. Furthermore, the amplitude change rate shows the ratio [%] of the amplitude Vamp calculated in the abnormal nozzle to the amplitude Vamp calculated in the normal nozzle. Additionally, the reset timing tep shows the time from the reference timing tref to the reset timing tep. The reference timing tref and... Figure 10 and Figure 11 Similarly, the timing of the residual vibration signal VD of a normal nozzle rising from a potential lower than the threshold potential VthC to the threshold potential VthC. Hereinafter, the amplitude Vamp calculated in a normal nozzle will sometimes be referred to as the normal nozzle amplitude Vamp, and the amplitude Vamp calculated in an abnormal nozzle will be referred to as the abnormal nozzle amplitude Vamp.

[0232] In addition, Figure 12 The text shows that in Figure 10 and Figure 11 The residual vibration signal VD of the normal nozzle and the residual vibration signal VD of the abnormal nozzle are shown, with the amplitude Vamp and amplitude change rate adjusted under the reset timing tep. Figure 12 The white dots indicate the normal nozzle amplitude, Vamp. Figure 12 The black dots indicate the abnormal nozzle amplitude Vamp. Figure 12 The quadrilateral represents the rate of change of amplitude.

[0233] like Figure 12 As shown, in both normal and abnormal nozzles, the amplitude Vamp increases as the time from the reference timing tref to the reset timing tep becomes longer. Furthermore, the amplitude difference DV between the amplitudes Vamp of the normal nozzle and the abnormal nozzle also increases as the time from the reference timing tref to the reset timing tep becomes longer. Additionally, in Figure 12 In the example shown, the absolute value of the ratio of the amplitude Vamp of the abnormal nozzle to the amplitude Vamp of the normal nozzle, i.e., the rate of change of amplitude, decreases as the time from the reference timing tref to the reset timing tep becomes longer, due to the increase in the amplitude Vamp of the normal nozzle.

[0234] Thus, in the first inspection mode, the amplitude Vamp can be adjusted by adjusting the reset timing tep. Therefore, in the first inspection mode, the sensitivity for determining the state of the ejection section D can be adjusted by adjusting the reset timing tep. For example, when the time from the reference timing tref to the reset timing tep is increased, the amplitude difference DV between the amplitude Vamp of the normal nozzle and the amplitude Vamp of the abnormal nozzle becomes larger compared to the case where the time from the reference timing tref to the reset timing tep is short. With a large amplitude difference DV, the resolution is improved compared to the case where the amplitude difference DV is small, thus improving the accuracy of determining whether the state of the ejection section D is normal.

[0235] Here, as in Figure 11 As explained, in either a normal or abnormal nozzle, when the reset timing tep coincides with the peak timing of the residual vibration signal VD, the amplitude Vamp and the amplitude VPK of the residual vibration signal VD are also consistent. Therefore, the sensitivity for determining the state of the ejection section D can be adjusted based on the condition that the reset timing tep coincides with the peak timing of the residual vibration signal VD of a normal nozzle.

[0236] Furthermore, the reset timing tep can also be adjusted for each nozzle N. In this scheme, for example, correction information for generating a pulse detection period signal Pcut that specifies the reset timing tep corresponding to each nozzle N can be stored in the storage unit 5. Additionally, in this scheme, for example, the two ejection sections D, each having two nozzles N, correspond to a "first ejection section" and a "second ejection section," respectively. Furthermore, in the signals corresponding to the ejection section D of the "first ejection section," the comparison signal CPc corresponds to a "first reference signal," comparison signals CP1 and CP2 correspond to a "first check signal," time information NTCc corresponds to "first reference signal information," time information NTC1 and NTC2 correspond to "first check signal information," and correction information corresponds to "first correction information." Similarly, in the signals corresponding to the ejection section D of the "second ejection section," the comparison signal CPc corresponds to a "second reference signal," comparison signals CP1 and CP2 correspond to a "second check signal," time information NTCc corresponds to "second reference signal information," time information NTC1 and NTC2 correspond to "second check signal information," and correction information corresponds to "second correction information."

[0237] Next, refer to Figure 13 The actions of inkjet printer 1 during the execution of ejection status determination processing are explained.

[0238] Figure 13 This is a flowchart illustrating an example of the actions of inkjet printer 1 when performing ejection status determination processing.

[0239] First, in step S100, the control unit 2 of the inkjet printer 1 functions as a drive control unit 22, selecting the ejector section D to be determined from the ejector sections D[1] to D[J]. Furthermore, in the following description, the case where ejector section D[j] is selected as the ejector section D to be determined will be illustrated.

[0240] Next, in step S120, the control unit 2 functions as the drive control unit 22 and determines whether to determine the state of the ejector section D in the first inspection mode. For example, the drive control unit 22 can determine the inspection mode based on operation information showing the operation performed on the inkjet printer 1. Alternatively, the drive control unit 22 can determine whether to determine the state of the ejector section D in the first inspection mode based on the purpose of determining the state of the ejector section D and the scenario in which the determination is made. Furthermore, the purpose of determining the state of the ejector section D and the scenario in which the determination is made, along with the correspondence between the inspection mode and the head unit 3 manufacturer, can be preset. For example, determining the state of the ejector section D in the first inspection mode can shorten the inspection time compared to the second inspection mode, so it is effective when determining the state of the ejector section D in a short time. In addition, immediately after the inkjet printer 1 is started, the ink in the cavity CV is in a stagnant state and is likely to be thickening. Therefore, determining the state of the ejector section D in the first inspection mode can be performed after the inkjet printer 1 is started, taking precedence over determining the state of the ejector section D in the second inspection mode. Therefore, a first inspection mode can be preset as the inspection mode after the inkjet printer 1 is started.

[0241] If the determination in step S120 is positive, i.e., the state of the ejection section D is determined using the first inspection mode, the drive control unit 22 transfers the processing to step S140. On the other hand, if the determination in step S120 is negative, i.e., the state of the ejection section D is determined using the second inspection mode, the drive control unit 22 transfers the processing to step S142.

[0242] In step S140, inkjet printer 1 generates a residual vibration signal VD. The step of generating the residual vibration signal VD, for example, although in... Figure 13 Not shown in the figure, but includes the following first and second steps. In the first step of generating the residual vibration signal VD, the control unit 2 functions as the drive control unit 22, controlling the switching circuit 31 of the head unit 3 so that the ejector part D[j], which is the object of determination, is driven. Then, in the second step of generating the residual vibration signal VD, the detection circuit 33 of the head unit 3 detects the detection signal Vout[j] showing the residual vibration generated in the ejector part D[j], and generates the residual vibration signal VD[j] based on the detection signal Vout[j].

[0243] Additionally, in step 140, although in Figure 13 Not shown in the diagram, but includes the step of supplying the pulse detection period signal Pcut and the mask signal MSK for the first inspection mode to the signal generation unit 60 of the inspection unit 6. For example, the drive control unit 22 can supply the pulse detection period signal Pcut and the mask signal MSK for the first inspection mode to the signal generation unit 60 of the inspection unit 6. Alternatively, the drive control unit 22 can also control the switching circuit 31 of the head unit 3 to supply the pulse detection period signal Pcut and the mask signal MSK for the first inspection mode to the signal generation unit 60 of the inspection unit 6. After performing the processing in step S140, the inkjet printer 1 transfers the processing to step S160.

[0244] In step S160, the signal generation unit 60 of the inspection unit 6 generates comparison signals CCPc, CCP1, and CCP2 in a first inspection mode. Then, the inspection unit 6 transfers the processing to step S180.

[0245] Furthermore, if the result of the determination in step S120 is negative, the process of step S142 is executed as described above. In step S142, the inkjet printer 1 operates in the same manner as in step S140, generating a residual vibration signal VD. However, in step S142, instead of the pulse detection period signal Pcut and mask signal MSK used for the first inspection mode, the pulse detection period signal Pcut and mask signal MSK used for the second inspection mode are supplied to the signal generation unit 60 of the inspection unit 6. After executing the process of step S142, the inkjet printer 1 transfers the process to step S162.

[0246] In step S162, the signal generation unit 60 of the inspection unit 6 generates comparison signals CCPc, CCP1, and CCP2 in a second inspection mode. Then, the inspection unit 6 transfers the processing to step S180.

[0247] In step S180, the determination unit 67 of the determination unit 64 of the inspection unit 6 determines the time length TCc of the comparison signal CCPc, the time length TC1 of the comparison signal CCP1, and the time length TC2 of the comparison signal CCP2.

[0248] Next, in step S200, the amplitude calculation circuit 68 of the determination unit 64 of the inspection unit 6 determines the calculation mode. Regarding the method for determining the calculation mode, in Figure 7 The explanation has already been provided, so the explanation is omitted.

[0249] Next, in step S220, the amplitude calculation circuit 68 of the determination unit 64 determines whether the calculation mode determined in step S200 is the first calculation mode.

[0250] If the determination in step S220 is positive, i.e., the calculation mode is the first calculation mode, the amplitude calculation circuit 68 calculates the amplitude Vamp in the first calculation mode in step S240 and transfers the processing to step S260. For example, in step S240, the amplitude calculation circuit 68 calculates the amplitude Vamp based on the time lengths TCc and TC1.

[0251] On the other hand, if the result of the determination in step S220 is negative, that is, if the calculation mode is the second calculation mode, the amplitude calculation circuit 68 calculates the amplitude Vamp in the second calculation mode in step S242 and transfers the processing to step S260. For example, in step S242, the amplitude calculation circuit 68 calculates the amplitude Vamp based on the time lengths TCc and TC2.

[0252] In step S260, the determination circuit 69 of the determination unit 64 determines the state of the ejection section D[j] based on the amplitude Vamp calculated in step S240 or step S242, and generates state information Cinf containing information indicating the result of the determination. Then, the determination circuit 69 outputs the state information Cinf to the control unit 2, ending the ejection state determination process.

[0253] Furthermore, the actions of inkjet printer 1 during the ejection status determination process are not limited to... Figure 13 The example shown. For example, the determination in step S120 can be performed before the processing in step S100. Alternatively, for example, the determination in step S220 can also be included in the processing in step S200. That is, the determination in step S220 and the processing in step S200 may not be strictly distinguished. Furthermore, for example, the step of supplying the pulse detection period signal Pcut and the mask signal MSK for the first inspection mode to the signal generation unit 60 of the inspection unit 6 can also be included in step 160. Similarly, the step of supplying the pulse detection period signal Pcut and the mask signal MSK for the second inspection mode to the signal generation unit 60 of the inspection unit 6 can also be included in step 162.

[0254] In this embodiment, the inkjet printer 1 includes: an ejection section D capable of ejecting ink according to an input drive signal COM; a signal generation section 60 that receives a residual vibration signal VD corresponding to residual vibration generated in the ejection section D upon input of the drive signal COM, and generates a comparison signal CCP based on the residual vibration signal VD; and a determination section 64 that determines the state of the ejection section D based on the comparison signal CCP. The signal generation section 60 has: a first inspection mode, which generates a first inspection mode signal corresponding to a first portion of the signal within a first period TPP1 of the residual vibration signal VD as the comparison signal CCP; and a second inspection mode, which generates a second inspection mode signal corresponding to a second portion of the signal within a second period TPP2 of the residual vibration signal VD as the comparison signal CCP. The first period TPP1 is shorter than the second period TPP2.

[0255] Furthermore, in this embodiment, the signal generation unit 60 and the determination unit 64 described above are included in the head unit control module HCM, which controls the head unit 3 equipped with an ejection section D capable of ejecting ink according to an input drive signal COM. Additionally, in this embodiment, the method for determining the state of the ejection section D is equivalent to a liquid ejection inspection method.

[0256] Thus, in this embodiment, the signal generation unit 60 has a first inspection mode and a second inspection mode as inspection modes for determining the state of the ejector section D. In the first inspection mode, the state of the ejector section D is determined using a first portion of the residual vibration signal VD, which is shorter than the second period TPP2, representing a first period TPP1. Therefore, in this embodiment, by determining the state of the ejector section D using the first inspection mode, the inspection time for determining the state of the ejector section D can be shortened. Furthermore, in the second inspection mode, the state of the ejector section D is determined using a second portion of the residual vibration signal VD, which is longer than the first period TPP1, representing a second period TPP2. Therefore, in the second inspection mode, multiple pieces of information, such as the period, phase difference accumulation, and amplitude attenuation of the residual vibration signal VD, can be determined based on the second portion of the residual vibration signal VD. Therefore, in this embodiment, by determining the state of the ejector section D using the second inspection mode, the state of the ejector section D can be determined with high accuracy.

[0257] Furthermore, in this embodiment, the first period TPP1 can be less than one-quarter of the period of the residual vibration signal VD, and the second period TPP2 can be more than one-half of the period of the residual vibration signal VD. In this solution, by determining the state of the ejection section D in the first inspection mode, compared with determining the state of the ejection section D in the second inspection mode, the inspection time can be shortened by more than one-quarter of the period of the residual vibration signal VD.

[0258] Furthermore, in this embodiment, the second period TPP2 is a period that follows the first period TPP1. In the second inspection mode, the signal generation unit 60 generates a second inspection mode signal without using the first portion of the residual vibration signal VD. In this solution, the first portion of the residual vibration signal VD, which is the first period TPP1 that precedes the second period TPP2, is not used to determine the state of the ejector section D. Therefore, in this solution, by determining the state of the ejector section D in the second inspection mode, even if the residual vibration signal VD immediately after being input to the signal generation unit 60 is superimposed with noise, the influence of this noise on the determination of the state of the ejector section D can be suppressed.

[0259] Furthermore, in this embodiment, the first period TPP1 may also begin before a first time elapses from the time the residual vibration signal VD is input to the signal generation unit 60. The first time is shorter than a quarter of the period of the residual vibration signal VD. Therefore, in the first inspection mode, it is possible to suppress the time from the time the residual vibration signal VD is input to the signal generation unit 60 to the generation of the comparison signal CCP from becoming longer. As a result, in this solution, by determining the state of the ejection section D in the first inspection mode, the inspection time for determining the state of the ejection section D can be shortened.

[0260] Furthermore, in this embodiment, the signal path of the residual vibration signal VD[j] from the ejection section D[j] to the signal generation section 60 is masked according to the masking timing based on the connection state specification signal Qs[j]. Also, in this embodiment, the determination section 64 can be configured to operate as follows: For example, the determination section 64 determines the state of the ejection section D based on multiple time information NTCs generated by using multiple comparison signals CP as signals that have been reset according to the reset timing tep based on the pulse detection period signal Pcut. When the masking timing is earlier than the reset timing tep, each of the multiple comparison signals CP is used as a signal whose potential at the masking timing is maintained until the reset timing tep to generate the various time information NTCs. In this solution, since the period from which the residual vibration signal VD[j] from the ejection section D[j] is input to the signal generation section 60 can be shortened, the inspection time can be reduced.

[0261] Furthermore, in this embodiment, a reset timing tep can also be set for each ejector section D. In this solution, for example, in each of the two ejector sections D, the state of that ejector section D is determined based on the timing information NTC generated using a pulse detection period signal Pcut and a comparison signal CP, which define the reset timing tep corresponding to that ejector section D. Therefore, in this solution, for example, even if the detection of the residual vibration signal VD deviates across multiple ejector sections D, the state of each ejector section D can be determined with good accuracy.

[0262] Second Implementation Method

[0263] Figure 14 This is a block diagram illustrating an example of the configuration of the inspection unit 6A according to the second embodiment. For comparison with... Figures 1 to 13 The same elements described herein are labeled with the same reference numerals, and detailed descriptions are omitted.

[0264] The inkjet printer 1 in this embodiment, except for having an inspection unit 6A instead of Figure 1 In addition to the inspection unit 6 shown, and Figure 1 The inkjet printer 1 shown is the same. Furthermore, in this embodiment, it is assumed that reset information Ntep is used instead. Figure 8 The pulse detection period signal Pcut is shown in the example. The reset information Ntep is an example of "reset signal" and "timing information". Furthermore, in this embodiment, it is assumed that the determination of the state of the ejection section D in the second inspection mode described in the first embodiment above is not performed. Therefore, in this embodiment, it is not used... Figure 8 The mask signal MSK is shown. However, in this embodiment, the state of the ejection section D can also be determined using the second inspection mode. Hereinafter, the description will focus on the inspection unit 6A.

[0265] The inspection unit 6A includes a signal generation unit 60A and a determination unit 64A. The signal generation unit 60A and the... Figure 7 The signal generation unit 60 shown is configured similarly to the adjustment unit 63, omitting the adjustment unit 63. For example, the signal generation unit 60A has a comparison unit 62 that includes comparison circuits 620, 621, and 622. Furthermore, the signal generation unit 60A outputs the comparison signal CPc generated by the comparison circuit 620, the comparison signal CP1 generated by the comparison circuit 621, and the comparison signal CP2 generated by the comparison circuit 622 to the determination unit 64A.

[0266] The determination unit 64A includes a timing specification circuit 65, a determination unit 67A, an amplitude calculation circuit 68, and a determination circuit 69. The amplitude calculation circuit 68 and the determination circuit 69 are... Figure 7The amplitude calculation circuit 68 and the determination circuit 69 shown are the same. For example, the amplitude Vamp of the residual vibration signal VD is determined by approximating the waveform of the residual vibration signal VD as a sine wave. Figure 7 The calculation is performed using formula (1) or formula (2) as described in the text.

[0267] The timing designation circuit 65 outputs reset information Ntep, indicating the reset timing tep, to the determination unit 67A, thereby designating the reset timing tep for the determination unit 67A. For example, the timing designation circuit 65 will... Figure 9 The reset information Ntep, which shows the time from the start of the supply of the residual vibration signal VD to the signal generation unit 60A at time t0 (i.e., the time from the start of the supply to the signal generation unit 60A), to the reset time tep, is output to the determination unit 67A. The reset information Ntep is stored, for example, in the storage unit 5. Hereinafter, the timing of the start of the supply of the residual vibration signal VD to the signal generation unit 60A is sometimes referred to as the measurement start timing. The measurement start timing is, for example,... Figure 9 The time t0 shown is... Figure 8 The connection state shown indicates the timing of the transition of the signal Qs[j] from low to high.

[0268] The determination unit 67A, for example, determines the time length TC from the timing ts (when the comparison signals CPc, CP1, and CP2 transition from a low level to a high level) to the reset timing tep. For example, the determination unit 67A includes determination circuits 670A, 671A, and 672A that respectively supply the comparison signals CPc, CP1, and CP2. Furthermore, reset information Ntep is supplied to each of the determination circuits 670A, 671A, and 672A.

[0269] For example, the determining circuit 670A determines the time length TCc from the timing tsc when the comparison signal CPc transitions from a low level to a high level to the reset timing tep indicated by the reset information Ntep. Specifically, for example, the determining circuit 670A measures the time from the start of timing measurement to the timing tsc. Then, the determining circuit 670A determines the time length TCc as the difference between the time from the start of timing measurement to the timing tsc and the time from the start of timing measurement to the reset timing tep. The time length TCc determined by the determining circuit 670A is, for example, compared with... Figure 9 The comparison signal CCPc is shown to be high during the period WCc, corresponding to the time length TCc. The determination circuit 670A outputs the time information NTCc, which shows the time length TCc determined based on the comparison signal CCPc and the reset information Ntep, to the amplitude calculation circuit 68.

[0270] Additionally, for example, the determining circuit 671A determines the time length TC1 from the timing ts1 when the comparison signal CP1 transitions from a low level to a high level to the reset timing tep indicated by the reset information Ntep. Specifically, for example, the determining circuit 671A measures the time from the start of timing measurement to timing ts1. Then, the determining circuit 671A determines the time length TC1 as the difference between the time from the start of timing measurement to timing ts1 and the time from the start of timing measurement to the reset timing tep. The time length TC1 determined by the determining circuit 671A is, for example, compared with... Figure 9 The duration of the period WC1 during which the comparison signal CCP1 is high corresponds to the time length TC1. The determination circuit 671A outputs the time information NTC1, which shows the time length TC1 determined based on the comparison signal CP1 and the reset information Ntep, to the amplitude calculation circuit 68.

[0271] Additionally, for example, the determining circuit 672A determines the time length TC2 from the timing ts2 when the comparison signal CP2 transitions from a low level to a high level to the reset timing tep indicated by the reset information Ntep. Specifically, for example, the determining circuit 672A measures the time from the start of timing measurement to timing ts2. Then, the determining circuit 671A determines the time length TC2 as the difference between the time from the start of timing measurement to timing ts2 and the time from the start of timing measurement to the reset timing tep. The time length TC2 determined by the determining circuit 672A is, for example, compared with... Figure 9 The duration of the comparison signal CCP2 being high corresponds to the time length TC2 of WC2. The determining circuit 672A outputs the time information NTC2, which is determined based on the comparison signal CP2 and the reset information Ntep, to the amplitude calculation circuit 68.

[0272] Here, the time length TCc is represented by timer tsc and reset timer tep using equation (9), and the time length TC1 is represented by timer ts1 and reset timer tep using equation (10). In addition, the time length TC2 is represented by timer ts2 and reset timer tep using equation (11).

[0273] TCc = tep - tsc … (9)

[0274] TC1 = tep - ts1 … (10)

[0275] TC2 = tep - ts2 … (11)

[0276] Thus, in this embodiment, it is not necessary to generate Figure 9 The comparison signals CCPc, CCP1, and CCP2 shown can be used to determine the time length TC.

[0277] Furthermore, the configuration of the inspection unit 6A is not limited to... Figure 14 The example shown. For instance, the timing designator circuit 65 could also be included in the control unit 2.

[0278] Alternatively, for example, the timing specifying circuit 65 can also supply the endpoint specifying signal, which transitions from high to low according to the reset timing tep, as reset information Ntep to the determining circuits 670A, 671A, and 672A. In this solution, for example, the timing specifying circuit 65 measures the elapsed time from the start of timing, and when the timing result matches the time from the start of timing to the reset timing tep, it causes the endpoint specifying signal to transition from high to low. Then, for example, the determining circuit 670A measures the time from the timing tsc, where the comparison signal CPc transitions from low to high, to the reset timing tep, where the endpoint specifying signal transitions from high to low, and determines the measurement result as the time length TCc. Similarly, the determining circuit 671A measures the time from timing ts1 to the reset timing tep and determines the measurement result as the time length TC1. Furthermore, the determining circuit 672A measures the time from timing ts2 to the reset timing tep and determines the measurement result as the time length TC2. In this scheme, the initial level of the endpoint designation signal is not particularly limited; it can be either high or low. However, if the initial level of the endpoint designation signal is low, the timing of the endpoint designation signal preceding the reset timing tep changes from low to high.

[0279] Alternatively, for example, the timing designation circuit 65 can also supply the endpoint designation signal that transitions from low to high level according to the reset timing tep as reset information Ntep to the determination circuits 670A, 671A and 672A.

[0280] In this embodiment, the comparison signal CP can also be generated based on a portion of the first period TPP1, which is less than one-quarter of the period of the residual vibration signal VD. The first period TPP1 is, for example,... Figure 9 The first period TPP1 is shown. In this embodiment, it is also preferable that the first period TPP1 begins before a first time has elapsed since the residual vibration signal VD was input to the signal generation unit 60A. The first time is, for example, a time shorter than one-quarter of the period of the residual vibration signal VD.

[0281] Next, refer to Figure 15 This section outlines the adjustment of the reset timing tep.

[0282] Figure 15This is an explanatory diagram illustrating the general outline of the adjustment of the reset timing tep. The vertical axis of the diagram shows the voltage [V] of the residual vibration signal VD with ground potential as a reference, and the horizontal axis shows the elapsed time from the start of the measurement timing, for example, the elapsed time [μs] from time t0.

[0283] In addition, Figure 15 In the example shown, the first peak PK of the residual vibration signal VD is the peak PK where the potential of the residual vibration signal VD reaches a minimum. Therefore, in Figure 15 In this context, we assume the range from the threshold potential VthC to the second peak PK of the residual vibration signal VD is compared with the threshold potentials VthC and Vth1. For example, in... Figure 15 In the above, the potential difference between the ground potential and the threshold potential VthC is 1.5V, and the potential difference between the ground potential and the threshold potential Vth1 is 2.5V.

[0284] in addition, Figure 15 The solid line represents the residual vibration signal VD of a normal nozzle, while the dashed line represents the residual vibration signal VD of an abnormal nozzle where ink flight deviation has occurred.

[0285] For example, if paper dust adheres near nozzle N, the surface of the ink inside nozzle N is drawn up by the paper dust in the ejection direction, thus causing an abnormality in ink flight deviation. In this case, as... Figure 15 As shown, in an abnormal nozzle with paper dust adhering to the vicinity of nozzle N, the period of residual vibration, i.e., the period of residual vibration signal VD, is slightly longer compared to a normal nozzle. Figure 15 In the example shown, the residual vibration signal VD of the abnormal nozzle varies by 4% periodically and 9% amplitude relative to the residual vibration signal VD of the normal nozzle. Thus, when the variation in the residual vibration signal VD of the abnormal nozzle relative to the normal nozzle is small, it becomes difficult to detect abnormalities in the ejection state by simply determining the waveform characteristics of the residual vibration signal VD. Therefore, in this embodiment, the accuracy of determining whether the ejection section D is in a normal state is improved by adjusting the reset timing tep.

[0286] For example, the time lengths TCc and TC1 can be adjusted by adjusting the reset timing tep. As a result, the time ratio, which is the ratio of time length TC1 to time length TCc, can be adjusted, and therefore the timing can be adjusted within... Figure 7 The amplitude Vamp is calculated from equation (1) as described in the text. Furthermore, in this embodiment, for example, it is not necessary to actually generate... Figure 9The comparison signal CCPc, etc., is a pulse with a duration TCc, thus extending the time from the start of measurement timing to the reset timing tep compared to the first embodiment described above. Therefore, in this embodiment, the adjustment range when adjusting the reset timing tep can be expanded. As a result, in this embodiment, the accuracy of determining whether the state of the ejection section D is normal can be easily adjusted.

[0287] For example, when improving the inspection accuracy of the state of the ejector section D, the reset timing tep is adjusted to be longer from the masking timing to the reset timing tep compared to cases with low inspection accuracy. Furthermore, for example, when shortening the inspection time of the state of the ejector section D, the reset timing tep is adjusted to be shorter from the masking timing to the reset timing tep compared to cases with long inspection times.

[0288] Furthermore, in this embodiment, the masking timing for masking the signal path of the residual vibration signal VD from the ejection section D[j] of the target to the signal generation unit 60 is set earlier than the reset timing tep. Therefore, in this embodiment, for example, if the time from the measurement start timing to the reset timing tep is extended, regardless of the reset timing tep, the ejection section D[j] can perform other operations at a timing later than the masking timing. Alternatively, in this embodiment, regardless of the reset timing tep, the ejection section D, which is different from the ejection section D[j], can operate as the ejection section D of the target, at a timing later than the masking timing. Thus, in this embodiment, even if the time from the measurement start timing to the reset timing tep is extended, the increase in inspection time can be suppressed.

[0289] Furthermore, in the scheme where the endpoint signal indicating the transition from high to low level according to the reset timing tep is used as the reset information Ntep, the reset timing tep of the ejector part D of the target object is earlier than the measurement start timing of the ejector part D of the next target object. However, in this scheme, the shielding timing can also be set earlier than the reset timing tep, thus suppressing the increase in inspection time. For example, in this scheme, if the timing is later than the shielding timing of the ejector part D of the target object, the drive signal COM can also be supplied to the ejector part D of the next target object according to a timing earlier than the reset timing tep of the ejector part D of the target object.

[0290] In addition, Figure 15 In this paper, it is assumed that the potential of the residual vibration signal VD, from the threshold potential VthC to the second peak PK of the residual vibration signal VD, is compared with the threshold potential VthC and Vth1, etc., but the present invention is not limited to such an approach. For example, it could also be in... Figure 15In the residual vibration signal VD shown, the potential of the residual vibration signal VD, from the threshold potential VthC to the first peak PK of the residual vibration signal VD, is compared with the threshold potential VthC and Vth1, etc. In this case, for example, instead of comparing the potential of the residual vibration signal VD with the threshold potential Vth1, the potential of the residual vibration signal VD is compared with a threshold potential lower than the threshold potential VthC, for example... Figure 9 The threshold potential Vthm1 shown is compared. The method for generating the comparison signal CP based on the comparison result of a threshold potential lower than the threshold potential VthC and the potential of the residual vibration signal VD is used in... Figure 9 The method for the threshold potential Vthm1 described in the text is the same.

[0291] Next, refer to Figure 16 This is used to illustrate the relationship between the reset timing tep, the amplitude Vamp, and the rate of change of amplitude.

[0292] Figure 16 This is an explanatory diagram used to illustrate the relationship between reset timing tep, amplitude Vamp, and rate of change of amplitude. Figure 12 One side of the vertical axis shows the voltage [V] of the amplitude Vamp relative to the threshold potential VthC, and the other side shows the amplitude change rate [%]. The horizontal axis shows the adjustment time [μs] of the reset timing tep. Furthermore, the adjustment time of the reset timing tep shows the time (μs) from the lower limit of the adjustment range of the reset timing tep. However, the adjustment range of the reset timing tep and the lower limit of that adjustment range are provided for ease of explanation and may not actually be set. Additionally, the amplitude change rate and... Figure 12 Similarly, the ratio [%] of the amplitude Vamp calculated in the abnormal nozzle to the amplitude Vamp calculated in the normal nozzle is shown.

[0293] Figure 16 The solid line represents the amplitude Vamp of a normal nozzle. Figure 16 The dashed line indicates the amplitude Vamp of the nozzle where an abnormal ink flight deviation has occurred. Figure 16 The dashed line indicates the rate of change of amplitude. Additionally, in Figure 16 In the comparative example, the amplitude difference and amplitude change rate of the residual vibration signal VD are calculated using the same method as the second inspection mode described in the first embodiment above, and are shown in parentheses. For example, the amplitude difference between the amplitude Vamp of the normal nozzle and the amplitude Vamp of the abnormal nozzle calculated by the comparative example is about 0.1V, and the amplitude change rate of the comparative example is about 0.1V.

[0294] In this embodiment, such as Figure 16As shown, in both normal and abnormal nozzles, the amplitude Vamp increases when the adjustment time of the reset timing tep becomes longer. Furthermore, the amplitude difference DV between the amplitudes Vamp of the normal nozzle and the abnormal nozzle also increases when the adjustment time of the reset timing tep becomes longer. Figure 16 In the example shown, the amplitude difference of the comparative example is around 0.1V, while the amplitude difference DV can be adjusted within a range from around 0.2V to around 1.0V. Furthermore, the absolute value of the ratio of the amplitude Vamp of the abnormal nozzle to the amplitude Vamp of the normal nozzle, i.e., the rate of change of amplitude, decreases as the adjustment time of the reset timing tep increases. Figure 16 In the example shown, the amplitude difference relative to the comparison example is around -9%, and the amplitude change rate can be adjusted within the range of -16% to -42%.

[0295] Thus, in this embodiment, by adjusting the reset timing tep, the amplitude Vamp and other parameters can be adjusted. For example, when the amplitude difference DV is large, the resolution is improved compared to when the amplitude difference DV is small, thereby improving the accuracy of determining whether the state of the ejection section D is normal. Therefore, in this embodiment, by adjusting the reset timing tep, the sensitivity for determining the state of the ejection section D can be adjusted. For example, in this embodiment, by adjusting the reset timing tep, the detection sensitivity for ink flight deviation can be improved.

[0296] Next, refer to Figure 17 This explains the actions of inkjet printer 1 when performing the ejection status determination process.

[0297] Figure 17 This is a flowchart illustrating an example of the actions of inkjet printer 1 when performing ejection status determination processing. Figure 17 The actions shown, in addition to those from Figure 13 The actions shown are omitted Figure 13 Apart from the processes shown in steps S120, S142, and S162, and the processes in steps S164 and S170, there is no difference between... Figure 13 The actions shown are the same. Figure 17 The explanation will focus on steps S164 and S170.

[0298] The processing in step S164 is performed after the processing in step S140. For example, after inkjet printer 1 performs the processing in step S140, it transfers the processing to step S164.

[0299] In step S164, the signal generation unit 60A of the inspection unit 6A compares the potential of the residual vibration signal VD with the threshold potentials VthC, Vth1, and Vth2 to generate comparison signals CPc, CP1, and CP2. Then, the inspection unit 6A transfers the processing to step S170.

[0300] In step S170, the timing designation circuit 65 of the determination unit 64A of the inspection unit 6A outputs the reset information Ntep, which shows the reset timing tep, to the determination unit 67A, thereby designating the reset timing tep for the determination unit 67A. Then, the inspection unit 6A transfers the processing to step S180.

[0301] In step S180, the determination unit 67A of the determination unit 64A of the inspection unit 6A is based, for example, on the determination unit 67A of the inspection unit 6A. Figure 14 Equations (9), (10), and (11) are used to determine the time lengths TCc, TC1, and TC2.

[0302] Furthermore, the actions of inkjet printer 1 during the ejection status determination process are not limited to... Figure 17 The example shown. For instance, the processing of step S170 can be performed before the processing of step S180, or it can be performed before the processing of step S100.

[0303] In this embodiment, the inkjet printer 1 includes: an ejection section D capable of ejecting ink according to an input drive signal COM; a signal generation section 60A that receives a residual vibration signal VD corresponding to the residual vibration generated in the ejection section D with the input of the drive signal COM, and generates a plurality of comparison signals CP based on the residual vibration signal VD; and a determination section 64A that determines the state of the ejection section D. The signal path of the residual vibration signal VD from the ejection section D[j] to the signal generation section 60A is masked according to a masking timing based on a connection state specification signal Qs[j]. The determination section 64A determines the state of the ejection section D based on a plurality of time information NTCs generated by using the plurality of comparison signals CP as signals that have been reset according to a reset timing tep based on reset information Ntep. When the masking timing is earlier than the reset timing tep, each of the plurality of time information NTCs is generated by using each of the plurality of comparison signals CP as signals whose potentials at the masking timing are maintained until the reset timing tep.

[0304] Furthermore, in this embodiment, the signal generation unit 60A and the determination unit 64A described above are included in the head unit control module HCM, which controls the head unit 3 equipped with an ejection section D capable of ejecting ink according to an input drive signal COM. Additionally, in this embodiment, the method for determining the state of the ejection section D is also equivalent to a liquid ejection inspection method.

[0305] Thus, in this embodiment, the signal path of the residual vibration signal VD from the ejection section D[j] to the signal generation section 60A is masked according to the masking timing. Furthermore, in this embodiment, when the masking timing is earlier than the reset timing tep, each of the multiple comparison signals CP is used as a potential held until the reset timing tep to generate the various timing information NTCs of the multiple timing information NTCs. Therefore, in this embodiment, for example, regardless of the reset timing tep, the ejection section D[j] can perform other operations at a timing later than the masking timing. Alternatively, in this embodiment, regardless of the reset timing tep, the ejection section D, which is different from the ejection section D[j] and is the object of determination, can operate at a timing later than the masking timing. That is, in this embodiment, for example, by extending the time from the start of the supply of the residual vibration signal VD to the signal generation section 60A to the reset timing tep, the inspection time for determining the state of the ejection section D can also be shortened.

[0306] Furthermore, in this embodiment, when shortening the inspection time for the state of the ejection section D, compared to a long inspection time, the reset timing tep can be adjusted to shorten the time from the masking timing to the reset timing tep. Thus, in this solution, by adjusting the reset timing tep, the inspection time for the state of the ejection section D can be easily shortened.

[0307] Furthermore, in this embodiment, to improve the inspection accuracy of the state of the ejection section D, the reset timing tep can be adjusted to increase the time from the masking timing to the reset timing tep, compared to a case of low inspection accuracy. Thus, in this solution, by adjusting the reset timing tep, the inspection accuracy of the state of the ejection section D can be easily improved. For example, when the time from the masking timing to the reset timing tep is increased, the time from the start of the timing of supplying the residual vibration signal VD to the signal generation unit 60A to the reset timing tep is also increased. Therefore, when the time from the masking timing to the reset timing tep is increased, the amplitude of the adjustment waveform based on the sine wave of the multiple comparison signals CP increases, thereby improving the resolution and inspection accuracy.

[0308] In addition, in this embodiment, the signal generation unit 60A may also generate multiple comparison signals CP based on the signal in the portion of the first period TPP1 that is less than one-quarter of the period of the residual vibration signal VD. In this way, the time spent generating the comparison signals CP can be shortened, thus reducing the inspection time for determining the state of the ejection section D.

[0309] Furthermore, in this embodiment, the signal generation unit 60A is made not electrically connected to the ejector unit D[j] by the connection state specification signal Qs[j]. For example, in this embodiment, the wiring Li[j] is set not to be electrically connected to the wiring Ls according to the connection state specification signal Qs[j]. Thus, in this embodiment, by means of the connection state specification signal Qs[j], the signal generation unit 60A is made not electrically connected to the ejector unit D[j], so the ejector unit D[j] can perform other operations before the determination of the state of the ejector unit D[j] ends. Alternatively, in this embodiment, the ejector unit D, which is different from the ejector unit D[j], can be made to operate before the determination of the state of the ejector unit D[j] ends.

[0310] Furthermore, in this embodiment, the multiple comparison signals CP can also be generated based on a portion of the residual vibration signal VD within a first period TPP1, which is less than one-quarter of the period of the residual vibration signal VD. The first period TPP1 begins before a first time elapses from the input of the residual vibration signal VD to the signal generation unit 60A, and this first time is shorter than the time corresponding to one-quarter of the period of the residual vibration signal VD. In this solution, it is possible to suppress the time from the input of the residual vibration signal VD to the signal generation unit 60A to the generation of the comparison signals CP from becoming longer. As a result, in this solution, the inspection time for determining the state of the ejection section D can be shortened.

[0311] Third Implementation Method

[0312] Figure 18 This is a block diagram illustrating an example of the configuration of the inspection unit 6B according to the third embodiment. For comparison with... Figures 1 to 17 The same elements described herein are labeled with the same reference numerals, and detailed descriptions are omitted.

[0313] The inkjet printer 1 involved in this embodiment, in addition to replacing... Figure 1 The inspection unit 6 shown has an inspection unit 6B, and is related to... Figure 1 The inkjet printer 1 shown is the same. Furthermore, in this embodiment, similar to the second embodiment described above, it is assumed that the determination of the state of the ejector section D in the second inspection mode described in the first embodiment is not performed. Therefore, in this embodiment, the inkjet printer 1 shown is not used. Figure 8 The mask signal MSK is shown. However, in this embodiment, the state of the ejection section D can also be determined using the second inspection mode. The following description focuses on the inspection unit 6B.

[0314] In inspection unit 6B, instead of Figure 14 The reset information Ntep is shown, while reset information Ntec, Nte1, and Nte2 are used instead. Reset information Ntec indicates the reset timing tec of the comparison signal CPc, and reset information Nte1 indicates the reset timing te1 of the comparison signal CP1. Additionally, reset information Nte2 indicates the reset timing te2 of the comparison signal CP2. Reset information Ntec, Nte1, and Nte2 are examples of "reset signal" and "timing information," respectively. Hereinafter, reset information Ntep, Ntec, Nte1, and Nte2 will sometimes be collectively referred to as reset information Nte. Furthermore, hereafter, reset timing tep, tec, te1, and te2 will sometimes be collectively referred to as reset timing te.

[0315] In addition to replacing the inspection unit 6B Figure 14 In addition to the determination unit 64B shown, the determination unit 64A is also present. Figure 14 The inspection unit 6A shown is similar. For example, the inspection unit 6B has a signal generation unit 60A and a determination unit 64B. The signal generation unit 60A and... Figure 14 The signal generation unit 60A shown is similar. For example, in this embodiment, as in the second embodiment described above, the timing tsc is the timing for the comparison signal CPc to change from a low level to a high level. In addition, the timing ts1 is the timing for the comparison signal CP1 to change from a low level to a high level, and the timing ts2 is the timing for the comparison signal CP2 to change from a low level to a high level.

[0316] In addition to replacing the judgment unit 64B Figure 14 The timing designation circuit 65 and the determination unit 67A shown are different from the timing designation circuit 66 and the determination unit 67B shown. Figure 14 The determination unit 64A shown is similar. For example, the determination unit 64B includes a timing specification circuit 66, a determination unit 67B, an amplitude calculation circuit 68, and a determination circuit 69. The amplitude calculation circuit 68 and the determination circuit 69 are similar to... Figure 7 The amplitude calculation circuit 68 and the determination circuit 69 shown are the same. For example, the amplitude Vamp of the residual vibration signal VD is obtained by approximating the waveform of the residual vibration signal VD as a sine wave and utilizing... Figure 7 The calculation is performed using formula (1) or formula (2) as described in the text.

[0317] Determining that Department 67B, in addition to replacing Figure 14The determining circuits 670A, 671A, and 672A shown are, except for determining circuits 670B, 671B, and 672B. Figure 14 The determination unit 67A shown is the same. The determination circuit 670B is the same as the determination circuit 670A, except that it uses a reset timer tec instead of reset timer tep to determine the time length TCc. The determination circuit 671B is the same as the determination circuit 671A, except that it uses a reset timer te1 instead of reset timer tep to determine the time length TC1. The determination circuit 672B is the same as the determination circuit 672A, except that it uses a reset timer te2 instead of reset timer tep to determine the time length TC2.

[0318] Thus, in this embodiment, the reset timings tec, te1, and te2 corresponding to the comparison signals CPc, CP1, and CP2 are used to determine the time lengths TCc, TC1, and TC2, respectively. Furthermore, in this embodiment, the reset timing te is adjusted for each ejection section D. Hereinafter, the operation of the timing designation circuit 66 will be explained using the case where ejection section D[j] is the object of determination as an example.

[0319] The timing designator circuit 66 outputs the reset information Ntec[j] corresponding to the comparison signal CPC to the determination circuit 670B of the determination unit 67B, thereby designating the reset timing tec[j] for the determination circuit 670B. Additionally, the timing designator circuit 66 outputs the reset information Nte1[j] corresponding to the comparison signal CP1 to the determination circuit 671B of the determination unit 67B, thereby designating the reset timing te1[j] for the determination circuit 671B. Furthermore, the timing designator circuit 66 outputs the reset information Nte2[j] corresponding to the comparison signal CP2 to the determination circuit 671B of the determination unit 67B, thereby designating the reset timing te2[j] for the determination circuit 671B.

[0320] For example, the timing designator circuit 66 has adder units 660, 661 and 662, and multiplier units 663 and 664.

[0321] The adder 660 adds the reference period length RTCc to the reference setting timing rtsc[j], and outputs the reset information Ntec, which shows the reset timing tec[j] as a result of the addition, to the determination circuit 670B. Furthermore, the reference period length RTCc is a parameter that determines the period length of a reference used to reduce the deviation of the amplitude Vamp of the multiple ejector sections D, and is shared by the J ejector sections D. For example, the reference period length RTCc can be set to about one-quarter of the period of the normal residual vibration signal VD. Information showing the reference period length RTCc is stored, for example, in the storage unit 5. Additionally, the reference setting timing rtsc[j] is, for example, the timing tsc when the comparison signal CPc changes from low to high when the ejector section D[j] is in a normal state. Information showing the reference setting timing rtsc[j] is stored, for example, in the storage unit 5 corresponding to the ejector section D[j].

[0322] The adder 661 receives the result of the multiplication from the multiplication 663. For example, the multiplication 663 multiplies the reference period length RTCc by the coefficient α and outputs the result to the adder 661. Then, the adder 661 adds the result of the multiplication of the reference period length RTCc and the coefficient α to the reference setting timing rts1[j] and outputs the reset information Nte1, which shows the reset timing te1[j] as the result of the addition, to the determination circuit 671B. Furthermore, the reference setting timing rts1[j] is, for example, the timing ts1 when the comparison signal CP1 changes from low to high when the state of the ejector D[j] is normal. Information showing the reference setting timing rts1[j] is stored in the storage unit 5, for example, corresponding to the ejector D[j].

[0323] Furthermore, the coefficient α is a coefficient used to adjust the sensitivity when determining the state of the ejector section D, and is determined to satisfy "α < 100%". For example, the coefficient α can be a coefficient shared by J ejector sections D, or it can be a coefficient determined for each ejector section D. Alternatively, the coefficient α can also be a coefficient determined for each group containing multiple ejector sections D. A group containing multiple ejector sections D can be, for example, a group of multiple ejector sections D corresponding to the nozzle array NL. Information showing the coefficient α is stored, for example, in storage unit 5. In addition, when the coefficient α is a coefficient determined for each ejector section D, information showing the coefficient α is stored in storage unit 5 corresponding to the ejector section D. In addition, when the coefficient α is a coefficient determined for each group of multiple ejector sections D, information showing the coefficient α is stored in storage unit 5 corresponding to the group.

[0324] The adder 662 receives the result of the multiplication performed by the multiplier 664. For example, the multiplier 664 multiplies the reference period length RTCc by the coefficient β and outputs the result of the multiplication to the adder 662. Then, the adder 662 adds the result of the multiplication of the reference period length RTCc and the coefficient β to the reference setting timing rts2[j], and outputs the reset information Nte1, which shows the reset timing te2[j] as the result of the addition, to the determination circuit 672B. Furthermore, the reference setting timing rts2[j] is, for example, the timing ts2 when the comparison signal CP2 changes from low to high when the state of the ejector D[j] is normal. Information showing the reference setting timing rts2[j] is stored in the memory unit 5, for example, corresponding to the ejector D[j].

[0325] Furthermore, the coefficient β is a coefficient used to adjust the sensitivity when determining the state of the ejector section D, and is determined to satisfy "α < 100%". For example, the coefficient β can be a coefficient shared by J ejector sections D, or it can be a coefficient determined for each ejector section D. Alternatively, the coefficient β can also be a coefficient determined for each group containing multiple ejector sections D. A group containing multiple ejector sections D can, for example, be a group of multiple ejector sections D corresponding to the nozzle array NL. Information showing the coefficient β is stored, for example, in storage unit 5. In addition, when the coefficient β is a coefficient determined for each ejector section D, information showing the coefficient β is stored in storage unit 5 corresponding to the ejector section D. In addition, when the coefficient β is a coefficient determined for each group of multiple ejector sections D, information showing the coefficient β is stored in storage unit 5 corresponding to the group.

[0326] Here, the reset timing tec[j] is expressed using the reference period length RTCc and the reference setting timing rtsc[j], and is given by equation (12). Additionally, the reset timing te1[j] is expressed using the reference period length RTCc, the reference setting timing rts1[j], and the coefficient α, and is given by equation (13). Furthermore, the reset timing te2[j] is expressed using the reference period length RTCc, the reference setting timing rts2[j], and the coefficient β, and is given by equation (14).

[0327] tec[j]=RTCc+rtsc[j]…(12)

[0328] te1[j]=α・RTCc+rts1[j]…(13)

[0329] te2[j]=β・RTCc+rts2[j]…(14)

[0330] The reset timing te1[j], as can be seen from equation (13), is adjusted by adjusting the coefficient α. Similarly, the reset timing te2[j], as can be seen from equation (14), is adjusted by adjusting the coefficient β.

[0331] Furthermore, the time length TCc[j] is expressed using timer tsc[j] and reset timer tec[j] by equation (15), and the time length TC1[j] is expressed using timer ts1[j] and reset timer te1[j] by equation (16). Additionally, the time length TC2[j] is expressed using timer ts2[j] and reset timer te2[j] by equation (17).

[0332] TCc[j]=tec[j]-tsc[j]…(15)

[0333] TC1[j]=te1[j]-ts1[j]…(16)

[0334] TC2[j]=te2[j]-ts2[j]…(17)

[0335] In addition, the time length TCc[j] is expressed according to equations (12) and (15) and by equation (18), the time length TC1[j] is expressed according to equations (13) and (16) and by equation (19), and the time length TC2[j] is expressed according to equations (14) and (17) and by equation (20).

[0336] TCc[j]=RTCc+rtsc[j]-tsc[j]…(18)

[0337] TC1[j]=α・RTCc+rts1[j]-ts1[j]…(19)

[0338] TC2[j]=β・RTCc+rts2[j]-ts2[j]…(20)

[0339] As can be seen from equation (18), the time length TCc[j] is represented by the sum of the reference period length RTCc and the value obtained by subtracting the timing tsc[j] from the reference setting timing rtsc[j]. Furthermore, as can be seen from equation (19), the time length TC1[j] is represented by the sum of the product of the reference period length RTCc and the coefficient α, and the value obtained by subtracting the timing ts1[j] from the reference setting timing rts1[j]. Furthermore, as can be seen from equation (20), the time length TC2[j] is represented by the sum of the product of the reference period length RTCc and the coefficient β, and the value obtained by subtracting the timing ts2[j] from the reference setting timing rts2[j]. In this embodiment, it is also not necessary to generate... Figure 9 The comparison signals CCPc, CCP1, and CCP2 shown can be used to determine the time length TC.

[0340] Furthermore, the configuration of the inspection unit 6B is not limited to... Figure 18The example shown. For example, the timing designation circuit 66 may be included in the control unit 2. Alternatively, the timing designation circuit 66 may also be included in the determination unit 67B. In the embodiment where the timing designation circuit 66 is included in the determination unit 67B, the time lengths TCc[j], TC1[j], and TC2[j] may be calculated based on equations (18), (19), and (20) instead of calculating the reset timings tec[j], te1[j], and te2[j]. In addition, for example, the reset information Ntec[j], Nte1[j], and Nte2[j] may also be stored in the storage unit 5 corresponding to the ejection unit D[j]. In this embodiment, the timing designation circuit 66 outputs the reset information Ntec[j], Nte1[j], and Nte2[j] read from the storage unit 5 to the determination unit 67B.

[0341] Additionally, for example, the endpoint designation signal for the level transition according to the reset timing tec[j], the endpoint designation signal for the level transition according to the reset timing te1[j], and the endpoint designation signal for the level transition according to the reset timing te2[j] can also be used as reset information Ntec[j], Nte1[j], and Nte2[j], respectively.

[0342] In this embodiment, the comparison signal CP can also be generated based on a portion of the first period TPP1, which is less than one-quarter of the period of the residual vibration signal VD. The first period TPP1 is, for example,... Figure 9 The first period TPP1 is shown. In this embodiment, it is also preferable that the first period TPP1 begins before a first time has elapsed since the residual vibration signal VD was input to the signal generation unit 60A. The first time is, for example, a time shorter than one-quarter of the period of the residual vibration signal VD.

[0343] Next, refer to Figure 19 This will explain the relationship between the residual vibration signal VD, the reset timing te, and the comparison signal CP.

[0344] Figure 19 This is an explanatory diagram illustrating the relationship between the residual vibration signal VD, the reset timing te, and the comparison signal CP. Furthermore, in Figure 19 In the text, the subscript [j] is omitted, but... Figure 19 In the description, the subscript [j] can be used appropriately.

[0345] Figure 19 The time t0 indicates the timing at which the supply of the residual vibration signal VD[j] to the signal generation unit 60A begins. The timing at which the supply of the residual vibration signal VD[j] to the signal generation unit 60A begins, for example, is... Figure 8The connection state shown specifies the timing of the transition of signal Qs[j] from low to high. Figure 19 In this example, for ease of understanding, the connection state specification signal Qs[j] is assumed to be maintained at a high level, and the comparison signal CP is explained accordingly. However, in this embodiment, the connection state specification signal Qs[j] can be changed from a high level to a low level, for example, according to the timing between timing ts1 and reset timing te1.

[0346] In addition, Figure 19 In the diagram, for ease of understanding, virtual comparison signals VCPc, VCP1, and VCP2 are shown. Figure 19 Within the parentheses. Compare signals VCPc, VCP1, and VCP2 with... Figure 9 The comparison signals CCPc, CCP1, and CCP2 shown correspond to each other. Furthermore, comparison signals VCPc, VCP1, and VCP2 are not actually generated signals. Comparison signal VCPc is a virtual signal that has been reset according to reset timing tec, comparison signal VCP1 is a virtual signal that has been reset according to reset timing te1, and comparison signal VCP2 is a virtual signal that has been reset according to reset timing te2. Figure 19 The diagram shows the comparison signals VCPc, VCP1, and VCP2 when the reset timings tec, te1, and te2 are the same.

[0347] Figure 19 Period Wc is the period from time tsc, when the compare signal CPc transitions from low to high, to time tec, and its length is the same as time length TCc. Period W1 is the period from time ts1, when the compare signal CP1 transitions from low to high, to time te1, and its length is the same as time length TC1. Period W2 is the period from time ts2, when the compare signal CP2 transitions from low to high, to time te2, and its length is the same as time length TC2.

[0348] When the ejector section D[j] is in a normal state, the time length TCc[j] from timing tsc[j] to reset timing tec[j] is consistent with the time length from reference setting timing rtsc[j] to reset timing tec[j], i.e., the reference cycle length RTCc. Furthermore, "consistent" means not only strictly consistent, but also includes cases with differences in the degree of error such as manufacturing error or operational error. Additionally, when the J ejector sections D are in a normal state, the time length TCc[j] of the J ejector sections D is consistent with the reference cycle length RTCc shared by the J ejector sections D.

[0349] Furthermore, when the ejection section D[j] is in a normal state, the time length TC1[j] from timing ts1[j] to reset timing te1[j] is the same as the product of the time length from reference setting timing rts1[j] to reset timing te1[j], i.e., the reference period length RTCc, and the coefficient α. Similarly, the time length TC2[j] from timing ts2[j] to reset timing te2[j] is the same as the product of the time length from reference setting timing rts2[j] to reset timing te2[j], i.e., the reference period length RTCc, and the coefficient β.

[0350] Here, as in Figure 18 As explained, the reset timing te1[j] is adjusted by adjusting the coefficient α. For example, by adjusting the coefficient α, the reset timing te1[j] can become the same timing as the reset timing tec[j], a timing later than the reset timing tec[j], or a timing earlier than the reset timing tec[j].

[0351] When the reset timing te1[j] is later than the reset timing tec[j], the amplitude Vamp is determined by setting the residual vibration signal VD's potential to reach the threshold potential Vth1 at a time earlier than the actual timing ts1[j]. For example, consider a situation where the reset timing te1[j] is shifted to match the reset timing tec[j] after the time length from the reference setting timing rts1[j] to the reset timing te1[j]. The shift amount in this case is set as the first shift amount. In this case, the reference setting timing rts1[j] is also shifted to the preceding timing by the first shift amount. Furthermore, as in... Figure 18 As explained, the time length TC1[j] is represented by the sum of the product of the reference period length RTCc and the coefficient α, and the value obtained by subtracting the timing ts1[j] from the reference set timing rts1[j]. While maintaining the measured time length TC1, the value obtained by subtracting the timing ts1[j] from the reference set timing is also maintained. Therefore, the timing ts1[j] is also shifted to an earlier timing by a first shift amount. In this case, the amplitude Vamp is determined by the threshold potential Vth1 reached at a timing earlier than the actual timing ts1[j] by the first shift amount.

[0352] Furthermore, when the reset timing te1[j] is earlier than the reset timing tec[j], the amplitude Vamp is determined by setting the residual vibration signal VD's potential to reach the threshold potential Vth1 at a time later than the actual timing ts1[j]. For example, consider a situation where the reset timing te1[j] is shifted to match the reset timing tec[j] after maintaining the time length from the reference setting timing rts1[j] to the reset timing te1[j]. The shift amount in this case is set as the second shift amount. In this case, the reference setting timing rts1[j] is also shifted to a later timing by the second shift amount. Additionally, when maintaining the measured time length TC1, the timing ts1[j] is also shifted to a later timing by the second shift amount. In this case, the amplitude Vamp is determined by setting the residual vibration signal VD's potential to reach the threshold potential Vth1 at a time later than the actual timing ts1[j] by the second shift amount.

[0353] The reset timing te2[j] is also adjusted by adjusting the coefficient β, just like the reset timing te1[j]. For example, if the reset timing te2[j] is a timing that occurs after the reset timing tec[j], the amplitude Vamp is determined by setting the residual vibration signal VD's potential to reach the threshold potential Vth2 at a timing that occurs before the actual timing ts2[j]. Alternatively, if the reset timing te2[j] is a timing that occurs before the reset timing tec[j], the amplitude Vamp is determined by setting the residual vibration signal VD's potential to reach the threshold potential Vth2 at a timing that occurs after the actual timing ts2[j].

[0354] Next, refer to Figure 20 This section outlines the adjustment of sensitivity when determining the state of the ejector section D. Hereinafter, the adjustment of sensitivity when determining the state of the ejector section D will sometimes be referred to simply as sensitivity adjustment.

[0355] Figure 20 This is an explanatory diagram outlining the adjustment of sensitivity when determining the state of the ejector section D. Figure 20 The explanation focuses on sensitivity adjustment based on the reset timing te1. Figure 20 The image shows the residual vibration signal VD of a normal nozzle and the residual vibration signal VD of an abnormal nozzle. Figure 20 The vertical axis shows the potential difference between the voltage [V] and the threshold potential VthC, which is referenced to the threshold potential VthC, and the horizontal axis shows the elapsed time [μs] from the reference timing tref. Furthermore, in Figure 20In this context, the reference timing tref is the timing at which the residual vibration signal VD of a normal nozzle rises from a potential lower than the threshold potential VthC to the threshold potential VthC. That is, the reference timing tref is the reference setting timing rtsc[j]. Furthermore, in... Figure 20 In this context, we assume the potential difference between the threshold potential VthC and the threshold potential Vth1 is 0.5V. Additionally, Figure 20 The dashed line indicates the tilt in the threshold potential Vth1 of the residual vibration signal VD of the normal nozzle, while the dashed line indicates the tilt after sensitivity adjustment.

[0356] In addition, Figure 20 In this context, we assume the amplitude VPK of the residual vibration signal VD from a normal nozzle is 1.0V, the amplitude VPK of the residual vibration signal VD from an abnormal nozzle is 0.9V, and the phase difference between the residual vibration signals VD from the normal nozzle and the abnormal nozzle is 0. Furthermore, in... Figure 10 In this context, we assume that the period of the residual vibration signal VD from a normal nozzle is the same as the period of the residual vibration signal VD from an abnormal nozzle, and that one-quarter of the period is 2.0 μs. That is, in Figure 20 In this context, we assume that in the residual vibration signal VD of a normal nozzle and the residual vibration signal VD of an abnormal nozzle, only the amplitude VPK, period, and phase of the amplitude VPK change.

[0357] When only the amplitude VPK, period, and phase change, the duration Wc of the comparison signal CPc remains unchanged in both normal and abnormal nozzles, while the duration W1 of the comparison signal CP1 changes. For example, the difference in duration W1 between the normal and abnormal nozzles for the comparison signal CP1 is the time difference Δts1.

[0358] like Figure 20 As shown, before sensitivity adjustment, the time difference Δts1 corresponds to the change in the threshold potential Vth1 of the residual vibration signal VD of the normal nozzle near the tilt. During sensitivity adjustment, for example, while maintaining the time difference Δts1, the reset timing te1 is adjusted by adding the product of the reference period length RTCc and the coefficient α to the reference setting timing rtsc, so that the tilt after sensitivity adjustment becomes abrupt. Figure 20 In the example shown, the reset timing te1 is adjusted to be a timing later than the reset timing tec by time tc1.

[0359] For example, consider the case where, after maintaining the time length from the reference setting time rts1 to the reset time te1, the reset time te1 is shifted by time tc1 to the preceding time to match the reset time tec. In this case, the reference setting time rts1 is also shifted by time tc1 to the preceding time. Furthermore, since the time difference Δts1 can be maintained, the timing ts1 of the abnormal nozzle is also shifted by time tc1 to the preceding time. Therefore, the tilt after sensitivity adjustment is as follows... Figure 20 As shown by the dashed line, the change becomes drastic compared to before the sensitivity adjustment.

[0360] Furthermore, in the method of simply amplifying the amplitude VPK of the residual vibration signal VD to make the tilting abrupt, the tilt of the residual vibration signal VD of the abnormal nozzle changes in the same way as the tilt of the residual vibration signal VD of the normal nozzle, thus changing the time difference Δts1. Therefore, it is difficult to properly adjust the sensitivity when determining the state of the ejection section D by simply amplifying the amplitude VPK of the residual vibration signal VD to make the tilting abrupt.

[0361] Next, refer to Figure 21 This will illustrate the relationship between the reset timing te and the amplitude Vamp calculated based on the time length TC.

[0362] Figure 21 This is an explanatory diagram used to illustrate the relationship between the reset timing te and the amplitude Vamp calculated based on the time length TC. Figure 21 The adjusted waveform shows the time length TCc adjusted by the reset timing tec and the time length TC1 adjusted by the reset timing te1 from the time length TCc. Figure 7 The amplitude Vamp is calculated by equation (1) as a sine wave. That is, the adjusted waveform is considered as a virtual waveform of the residual vibration signal VD with an amplitude Vamp calculated based on the time lengths TCc and TC1, and is not limited to being the same waveform as the residual vibration signal VD actually output from the detection circuit 33. In addition, Figure 21 The comparison signal VCPc is a virtual signal that has been reset according to the reset timing tec, and the comparison signal VCP1 is a virtual signal that has been reset according to the reset timing te1.

[0363] exist Figure 21 In the coordinate graphs of the residual vibration signal VD and the adjusted waveform, the vertical axis shows the potential difference between the voltage [V] and the threshold potential VthC, which is based on the threshold potential VthC, and the horizontal axis shows the elapsed time [μs] from the reference timing tref. Furthermore, in Figure 21In this context, the reference timing tref is also the timing of the residual vibration signal VD of the normal nozzle rising from a potential lower than the threshold potential VthC to the threshold potential VthC. The potential difference between the threshold potential VthC and the threshold potential Vth1 is 0.5V.

[0364] in addition, Figure 21 The residual vibration signal VD of the normal nozzle and the residual vibration signal VD of the abnormal nozzle are shown in the figure. Figure 20 The residual vibration signal VD of the normal nozzle and the residual vibration signal VD of the abnormal nozzle are the same as described above. For example, the amplitude VPK of the residual vibration signal VD of the normal nozzle is 1.0V, and the amplitude VPK of the residual vibration signal VD of the abnormal nozzle is 0.9V. The phase difference between the residual vibration signals VD of the normal nozzle and the abnormal nozzle is 0. Furthermore, one-quarter of the period of the residual vibration signals VD of the normal nozzle and the abnormal nozzle is 2.0μs. Therefore, the residual vibration signals VD of the normal nozzle and the abnormal nozzle, after a timing interval of 2.0μs from the reference timing tref, form the peak PK.

[0365] exist Figure 21 In the diagram, for both normal and abnormal nozzles, six adjustment waveforms corresponding to the six reset timings te1 are shown. Furthermore, in... Figure 21 The diagram shows the adjustment waveform and the virtual comparison signal VCP1 when the reset timing te1 is shifted to match the reset timing tec.

[0366] like Figure 21 As shown, the time ratio, i.e., the ratio of the time length TC1 to the time length TCc when the state of the ejection section D is normal, is adjusted by adjusting the reset time te1. In both normal and abnormal nozzles, the amplitude Vamp of the adjustment waveform increases when the time ratio of the time length TC1 to the time length TCc when the state of the ejection section D is normal is large, compared to when the time ratio is small.

[0367] Reset timer te1, for example, by adjusting in Figure 18 The coefficient α in equation (13) is adjusted. The coefficient α corresponds to the ratio of the time length TC1 to the time length TCc when the state of the ejector D is normal, i.e., the time ratio. In addition, the reset timing te1 is adjusted, for example, by adjusting the time length TC1 to the time length TCc when the state of the ejector D is normal. Figure 18 The coefficient α of equation (13) explained in the text is adjusted. In addition, the reset timing te1 can also be adjusted by adjusting the reference setting timing rts1. In adjusting the reference setting timing rts1, the ratio of the time length TC1 to the time length TCc when the state of the ejection section D is normal can also be adjusted, i.e., the time ratio.

[0368] Here, the adjustment amount of the time length TC1 corresponding to the adjustment of the reset timing te1 is equivalent to the correction amount of the comparison signal CP1. Additionally, although in Figure 21 Not illustrated, but the adjustment of the time length TC2 corresponding to the adjustment of the reset timing te2 is equivalent to the correction amount of the comparison signal CP2. Alternatively, the change in amplitude Vamp caused by the adjustment of the time length TC1 can also be captured as the correction amount.

[0369] Next, refer to Figure 22 This explains the relationship between the ratio of the time length TC1 to the time length TCc when the ejection section D is in a normal state, i.e., the time ratio, and the amplitude Vamp and the rate of change of amplitude.

[0370] Figure 22 This is an explanatory graph used to illustrate the relationship between the time ratio of two time lengths TCc and TC1 and the amplitude Vamp and the rate of change of amplitude. Figure 22 One side of the vertical axis shows the voltage [V] of the amplitude Vamp relative to the threshold potential VthC, and the other side shows the rate of change of amplitude [%]. The horizontal axis shows the time ratio [%] of the time lengths TCc and TC1. The rate of change of amplitude and... Figure 12 Similarly, the ratio [%] of the amplitude Vamp calculated in the abnormal nozzle to the amplitude Vamp calculated in the normal nozzle is shown. Additionally, the time ratio of time lengths TCc and TC1 shows the ratio [%] of time length TC1 to time length TCc when the ejection section D is in a normal state. For example, the time ratio corresponds to... Figure 18 The coefficient α of equation (13) or equation (19) as described in the text.

[0371] Figure 22 The white dots indicate the normal nozzle amplitude, Vamp. Figure 22 The black dots indicate the abnormal nozzle amplitude Vamp. Figure 22 The quadrilateral represents the rate of change of amplitude.

[0372] like Figure 22 As shown, for either a normal or abnormal nozzle, the amplitude Vamp increases as the time ratio of TCc to TC1 increases. Furthermore, the amplitude difference DV between the normal and abnormal nozzle amplitudes Vamp increases as the time ratio of TCc to TC1 increases. Additionally, the absolute value of the ratio of the abnormal nozzle amplitude Vamp to the normal nozzle amplitude Vamp, i.e., the rate of change of amplitude, increases as the time ratio of TCc to TC1 increases. Figure 16In the example shown, when the time ratio of time lengths TCc and TC1 is set to 90%, the amplitude change rate increases to three times the amplitude change rate when the time ratio of time lengths TCc and TC1 is 67%.

[0373] Thus, in this embodiment, by adjusting the time ratio of the time lengths TCc and TC1, for example, the coefficient α, the amplitude Vamp and the amplitude change rate can be adjusted. Furthermore, the time ratio of the time lengths TCc and TC1 can also be determined for each ejector section D based on the amount of ink ejected when the ejector section D is in a normal state. For example, if the i-th ejector section D, which is different from the j-th ejector section D[j], is designated as ejector section D[i], the time ratio of the time lengths TCc and TC1 can be adjusted based on the amount of ink ejected in both ejector section D[j] and ejector section D[i]. Furthermore, the variable i is a natural number satisfying "1≤i≤J" and "i≠j". Additionally, hereinafter, when the components or signals of the inkjet printer 1 correspond to ejector section D[i] among the J ejector sections D, the reference numerals used to represent those components or signals are sometimes marked with a subscript [i].

[0374] For example, when the amount of ink ejected from ejector section D[i] is less than that ejected from ejector section D[j], the amplitude VPK[i] of the residual vibration signal VD[i] of ejector section D[i] tends to be smaller than the amplitude VPK[j] of the residual vibration signal VD[j] of ejector section D[j]. Therefore, when the amount of ink ejected from ejector section D[i] is less than that ejected from ejector section D[j], for example, the time ratio of time lengths TCc and TC1 can be adjusted so that the adjustment amount of amplitude Vamp[i] of ejector section D[i] is larger than the adjustment amount of amplitude Vamp[j] of ejector section D[j]. In this case, the time ratio of time lengths TCc and TC1 can also be adjusted by adjusting the coefficient α for each ejector section D. That is, the coefficient α can have different values ​​in ejector section D[j] and ejector section D[i]. Hereinafter, the coefficient α used in the calculation of reset timing te1[j] will sometimes be referred to as coefficient α[j], and the coefficient α used in the calculation of reset timing te1[i] will be referred to as coefficient α[i]. Reset timing te1[j] is an example of "first timing".

[0375] Furthermore, in the above examples, ejector D[j] is an example of a "first ejector," and ejector D[i] is an example of a "second ejector." Additionally, residual vibration signal VD[j] is an example of a "first residual vibration signal," and residual vibration signal VD[i] is an example of a "second residual vibration signal." Comparison signal CPc[j] of ejector D[j] is an example of a "first reference signal," and comparison signals CP1[j] and CP2[j] of ejector D[j] are examples of "first check signals." Timing information NTCc[j] of ejector D[j] is an example of "first reference signal information," and timing information NTC1[j] and NTC2[j] of ejector D[j] are examples of "first check signal information." Furthermore, information showing the reference setting timing rts1[j] and information showing the coefficient α[j] are examples of "first correction information." Similarly, the comparison signal CPc[i] of the ejector section D[i] is an example of a "second reference signal", and the comparison signals CP1[i] and CP2[i] of the ejector section D[i] are examples of "second check signals". The timing information NTCc[i] of the ejector section D[i] is an example of "second reference signal information", and the timing information NTC1[i] and NTC2[i] of the ejector section D[i] are examples of "second check signal information". In addition, the information showing the reference setting timing rts1[i] and the information showing the coefficient α[i] are examples of "second correction information". However, when the coefficient α is shared in both the ejector section D[j] and the ejector section D[i], the information showing the coefficient α may not be included in the "first correction information" and the "second correction information".

[0376] In this embodiment, as described above, the time ratio of time length TCc and time length TC1 can be adjusted in both ejection section D[j] and ejection section D[i] according to the amount of ink ejected. Therefore, in this embodiment, ejection section D[j] and ejection section D[i] can be inspected using the same reference.

[0377] Next, refer to Figure 23 Here is an example illustrating the deviation between nozzle N and amplitude Vamp calculated based on time lengths TCc and TC1.

[0378] Figure 23 This is an illustrative diagram illustrating an example of the deviation between nozzle N and amplitude Vamp calculated based on time lengths TCc and TC1. Figure 23 The results obtained through experiments are shown in the figure. Figure 23 The vertical axis shows the potential difference between the voltage [V] and the threshold potential VthC, which is based on the threshold potential VthC. The horizontal axis shows the nozzle number used to identify the J nozzles N. Additionally, in Figure 23The example shown is a comparative example in which the amplitude Vamp of the residual vibration signal VD is calculated using the same method as the second inspection mode described in the first embodiment above, without adjusting for the deviation between nozzles. In the comparative example, the deviation ΔVex of the amplitude Vamp in the J nozzles N is approximately 2V, and the amplitude change rate is approximately -10%.

[0379] In this embodiment, the reset timing te is adjusted for each ejection section D, so the time lengths TCc and TC1 under normal conditions for ejection section D are approximately the same in the J nozzles N corresponding to the J ejection sections D. Therefore, as Figure 23 As shown, the amplitude Vamp calculated based on the time lengths TCc and TC1 is approximately the same value across the J nozzles N. That is, the deviation ΔVamp of the amplitude Vamp across the J nozzles N is almost zero. However, due to environmental changes such as temperature variations, deviations from repeated measurements, and aging and deterioration of the piezoelectric element PZ, the characteristics of each nozzle N change, therefore the deviation ΔVamp of the amplitude Vamp across the J nozzles N is not strictly zero. Furthermore, in this embodiment, compared to the comparative example, the amplitude change rate can be improved from approximately -10% to approximately -23%.

[0380] Thus, in this embodiment, compared to the comparative example, both the amplitude change rate can be improved and the deviation ΔVamp of the amplitude Vamp in the J nozzles N can be significantly reduced. Furthermore, in this embodiment, for example, by adjusting the coefficient α, both the deviation ΔVamp of the amplitude Vamp in the J nozzles N can be reduced, and the sensitivity in determining the state of the ejection section D can be improved.

[0381] Next, refer to Figure 24 Here is an example illustrating the amplitude Vamp calculated when the sensitivity for determining the state of the ejector D is adjusted.

[0382] Figure 24 This is an explanatory diagram illustrating an example of the amplitude Vamp calculated when the sensitivity for determining the state of the ejector D is adjusted. Figure 24 The results obtained through experiments are shown in the figure. Figure 24 The diagram shows the amplitude Vamp when the sensitivity for determining the state of the ejector D is adjusted by changing the time ratio of the time length TCc and TC1 when the ejector D is in a normal state. Figure 24 In this context, we assume that the coefficient α is shared by J ejector sections D, and that the time ratio of time lengths TCc and TC1 is adjusted by adjusting this coefficient α.

[0383] like Figure 24As shown, when the time ratio of TCc to TC1 is any one of 70%, 80%, or 90%, the deviation ΔVamp of the amplitude Vamp in the J nozzles N is almost zero. Furthermore, in Figure 24 In the example shown, as in Figure 22 As explained, when the time ratio of the time lengths TCc and TC1 increases, the amplitude Vamp, the amplitude difference DV between the normal nozzle amplitude Vamp and the abnormal nozzle amplitude Vamp, and the absolute value of the amplitude change rate increase.

[0384] Next, refer to Figure 25 This explains the actions of inkjet printer 1 when performing the ejection status determination process.

[0385] Figure 25 This is a flowchart illustrating an example of the actions of inkjet printer 1 when performing ejection status determination processing. Figure 25 The actions shown, besides replacing Figure 17 In addition to performing a series of processes including steps S172, S174, and S176, the process shown in step S170 is performed in conjunction with... Figure 17 The actions shown are the same. Figure 25 In this example, taking the case where the ejection part D of the determined object is ejection part D[j] as an example, the explanation will focus on a series of processes in steps S172, S174 and S175.

[0386] The series of processes in steps S172, S174, and S175 are executed by the timing designation circuit 66 of the determination unit 64B of the inspection unit 6B after the processing in step S164 is performed. For example, after the inkjet printer 1 performs the processing in step S164, the processing is transferred to step S172.

[0387] In step S172, the timing specifying circuit 66 acquires information indicating the reference period length RTCc, information indicating the coefficient α, and information indicating the coefficient β. For example, the timing specifying circuit 66 reads the information indicating the reference period length RTCc, the information indicating the coefficient α, and the information indicating the coefficient β from the storage unit 5. Then, the checking unit 6B transfers the processing to step S174.

[0388] In step S174, the timing designator circuit 66 acquires information showing the reference setting timing rtsc[j], rts1[j], and rts2[j] of the ejection section D[j] indicating the target to be determined. For example, the timing designator circuit 66 reads the information showing the reference setting timing rtsc[j], rts1[j], and rts2[j] from the storage unit 5. Then, the inspection unit 6B transfers the processing to step S176.

[0389] In step S176, the timing designation circuit 66 calculates the reset timing tec[j], te1[j], and te2[j] of the ejection section D[j] of the determined object. For example, the timing designation circuit 66 is based on... Figure 18 Equations (12), (13), and (14) described herein calculate the reset timings tec[j], te1[j], and te2[j]. Then, the timing designator circuit 66 outputs the reset information Ntec[j] showing the reset timing tec[j], the reset information Nte1[j] showing the reset timing te1[j], and the reset information Nte2[j] showing the reset timing te2[j] to the determination unit 67B. Thus, the reset timings tec[j], te1[j], and te2[j] are designated to the determination unit 67B. After the timing designator circuit 66 outputs the reset information Ntec[j], Nte1[j], and Nte2[j] to the determination unit 67B, the checking unit 6A transfers the processing to step S180.

[0390] In step S180, the determination unit 67B of the determination unit 64B of the inspection unit 6B is based on, for example, in Figure 18 Equations (15), (16), and (17) described in the text determine the time lengths TCc[j], TC1[j], and TC2[j].

[0391] Furthermore, the actions of inkjet printer 1 during the ejection status determination process are not limited to... Figure 25 The example shown. For example, the series of processes in steps S172, S174, and S175 can be performed after the process in step S100 and before the process in step S180, or they can be performed before the process in step S140. In addition, for example, if the coefficients α and β are shared in J ejector sections D, the process in step S172 can also be performed before the process in step S100. Alternatively, the reference period length RTCc, the coefficient α, and the coefficient β can be preset in the timing designator circuit 66. In this case, step S172 is omitted. In addition, for example, if the coefficients α and β are determined for each ejector section D, in step S172, the timing designator circuit 66 obtains information on the coefficients α and β of the ejector section D[j] indicating the object of determination.

[0392] Furthermore, for example, the processing in step S172 and the processing in step S174 may not be strictly distinguished. Also, for example, the processing in step S176 and the processing in step S180 may not be strictly distinguished. For example, the checking unit 6B may be based on the reset timing tec[j], te1[j], and te2[j] without calculating the reset timings. Figure 18The time lengths TCc[j], TC1[j], and TC2[j] are determined using equations (18), (19), and (20) as described herein. In this scheme, for example, the timing designator circuit 66 can output information showing the reference period length RTCc, information showing the coefficient α, and information showing the coefficient β to the determination unit 67B in step S172. Then, in step S174, the timing designator circuit 66 can output information showing the reference setting timing rtsc[j], rts1[j], and rts2[j] of the ejection section D[j] of the determination object to the determination unit 67B.

[0393] In this embodiment, the inkjet printer 1 includes: an ejection section D[j] and an ejection section D[i], capable of ejecting ink according to an input drive signal COM; a signal generation unit 60A, which generates a comparison signal CP1[j] and a comparison signal CPc[j] based on the residual vibration signal VD[j] when a residual vibration signal VD[j] corresponding to the residual vibration generated in the ejection section D[j] with the input of the drive signal COM is input, and generates a comparison signal CP1[i] and a comparison signal CPc[i] based on the residual vibration signal VD[i] when a residual vibration signal VD[i] corresponding to the residual vibration generated in the ejection section D[i] with the input of the drive signal COM is input; a determination unit 64B, which determines the state of the ejection section D[j] and the ejection section D[i] respectively; and a storage unit 5, which stores information showing the reference setting time rts1[j] and information showing the reference setting time rts1[i]. The determination unit 64B determines the state of the ejection section D[j] using time information NTC1[j] generated based on the reference setting time rts1[i] and the comparison signal CP1[j], and time information NTCc[j] generated based on the comparison signal CPc[j], without using the reference setting time rts1[i].

[0394] Furthermore, in this embodiment, the signal generation unit 60A and the determination unit 64B described above are included in the head unit control module HCM, which controls the head unit 3, which has an ejection section D[j] and an ejection section D[i] capable of ejecting ink according to the input drive signal COM. Additionally, in this embodiment, the method for determining the state of the ejection section D[j] and the ejection section D[i] is also equivalent to a liquid ejection inspection method.

[0395] Thus, in this embodiment, a reference setting time rts1[j] for generating time information NTC1[j] and a reference setting time rts1[i] for generating time information NTC1[i] are prepared respectively. Therefore, in this embodiment, deviations in the time information NTC1, and more accurately, for example, the time length TC1 shown by the time information NTC1, can be suppressed in the ejection section D[j] and ejection section D[i]. As a result, in this embodiment, ejection section D[j] and ejection section D[i] can be checked with the same reference. In addition, in this embodiment, since deviations in the time length TC1 shown by the time information NTC1 can be suppressed, it is not necessary to perform separate processing for deviations for ejection section D in the process of determining using time information NTC1. Therefore, in this embodiment, the state of ejection section D can be checked efficiently. As a result, in this embodiment, the length of the inspection time for determining the state of ejection section D can be suppressed. In addition, in this embodiment, the time information NTC1 is generated based on the reference setting time rts1 and the comparison signal CP1. For example, in this embodiment, in order to shorten the inspection time for determining the state of the ejection section D, a timing information NTC1 can be generated using a reference setting timing rts1 and a reset comparison signal CP1. That is, in this embodiment, the inspection time for determining the state of the ejection section D can be shortened.

[0396] Furthermore, in this embodiment, the time information NTC1[j] is generated based on information that has been corrected for the comparison signal CP1[j] using the reference setting timing rts1[j], and the time information NTC1[i] is generated based on information that has been corrected for the comparison signal CP1[i] using the reference setting timing rts1[i]. When the amount of ink ejected from the ejector section D[i] is less than the amount of ink ejected from the ejector section D[j], the correction amount using the reference setting timing rts1[i] is greater than the correction amount using the reference setting timing rts1[j]. Thus, in this embodiment, the correction amount can be adjusted according to the amount of ink ejected from both the ejector section D[j] and the ejector section D[i]. Therefore, in this embodiment, both the ejector section D[j] and the ejector section D[i] can be checked using the same reference.

[0397] Furthermore, in this embodiment, the comparison signal CPc[j] indicates whether the residual vibration signal VD[j] is above the threshold potential VthC, the comparison signal CP1[j] indicates whether the residual vibration signal VD[j] is above the threshold potential Vth1, which is different from the threshold potential VthC, and the time information NTC1[j] is generated by using the comparison signal CP1[j] as a signal that indicates the residual vibration signal VD[j] is above the threshold potential Vth1 before the reset time te1[j] corresponding to the reference setting time rts1[j], regardless of whether the residual vibration signal VD[j] changes to be below the threshold potential Vth1. Thus, in this embodiment, by correcting the period during which the comparison signal CP1[j] indicates that the residual vibration signal VD[j] is above the threshold potential Vth1, the adjustment waveform based on the sine wave of the comparison signal CP1[j] can be easily corrected. Furthermore, in this embodiment, for example, by extending the time from the start of the supply of the residual vibration signal VD[j] to the signal generation unit 60A to the reset time te1[j], the inspection time for determining the state of the ejection unit D[j] can also be shortened.

[0398] Furthermore, in this embodiment, the signal path of the residual vibration signal VD[j] from the ejection section D[j] to the signal generation section 60A is masked according to the masking timing based on the connection state specified signal Qs[j]. The determination section 64B generates timing information NTC1[j] by using the comparison signal CP1[j] as a signal that has been reset according to the reset timing te1[j] corresponding to the reference setting timing rts1[j]. When the masking timing is earlier than the reset timing te1[j], the timing information NTC1[j] is generated by using the comparison signal CP1[j] as a signal whose potential at the masking timing is maintained until the reset timing te1[j]. Thus, in this embodiment, for example, regardless of the reset timing te1[j], the ejection section D[j] can perform other operations at a timing later than the masking timing. Alternatively, in this embodiment, regardless of the reset timing te1[j], the ejection part D[i], which is different from the ejection part D[j], can be operated at a timing later than the shielding timing. Therefore, in this embodiment, for example, if the time from the start of the supply of the residual vibration signal VD[j] to the signal generation unit 60A to the reset timing te1[j] is extended, the inspection time for determining the state of the ejection part D[j] can also be shortened.

[0399] In addition, in this embodiment, the signal generation unit 60A may also generate comparison signals CP1[j] and CPc[j] based on a portion of the first period TPP1 of the residual vibration signal VD[j] that is less than one-quarter of the period of the residual vibration signal VD[j]. In this way, the time spent generating comparison signals CP1[j] and CPc[j] can be shortened, and thus the inspection time for determining the state of the ejection section D[j] can be shortened.

[0400] Furthermore, in this embodiment, the signal generation unit 60A is made not electrically connected to the ejector unit D[j] by the connection state specification signal Qs[j]. For example, in this embodiment, the wiring Li[j] is set not to be electrically connected to the wiring Ls according to the connection state specification signal Qs[j]. Thus, in this embodiment, by means of the connection state specification signal Qs[j], the signal generation unit 60A is not electrically connected to the ejector unit D[j], so the ejector unit D[j] can perform other operations before the determination of the state of the ejector unit D[j] ends. Alternatively, in this embodiment, the ejector unit D[i], which is different from the ejector unit D[j], can be made to operate before the determination of the state of the ejector unit D[j] ends.

[0401] Furthermore, in this embodiment, the comparison signals CP1[j] and CPc[j] may also be generated based on a portion of the residual vibration signal VD[j] within a first period TPP1, which is less than one-quarter of the period of the residual vibration signal VD[j]. The first period TPP1 begins before a first time elapses from the input of the residual vibration signal VD[j] to the signal generation unit 60A, and this first time is shorter than the time corresponding to one-quarter of the period of the residual vibration signal VD[j]. In this solution, it is possible to suppress the time from the input of the residual vibration signal VD[j] to the generation of the comparison signals CP1[j] and CPc[j] from the signal generation unit 60A becoming longer. As a result, in this solution, the inspection time for determining the state of the ejection section D[j] can be shortened.

[0402] 2. Variations

[0403] The above methods can be modified in various ways. Specific modifications are illustrated below. Two or more modifications selected from the following examples can be appropriately combined without contradiction. Furthermore, elements that function or are equivalent to the implementation methods in the modifications illustrated below are referenced in the accompanying drawings described above, and detailed descriptions are omitted where appropriate.

[0404] First variation

[0405] In the above embodiments, the inspection units 6, 6A, and 6B may also have a switching unit that switches whether or not the residual vibration signal VD is supplied to the comparison unit 62. In this modified example, the control signal for switching whether or not the residual vibration signal VD is supplied to the comparison unit 62, i.e., the control signal of the switching unit, may also be captured as a "masking signal".

[0406] Figure 26 This is a block diagram illustrating an example of the configuration of the inspection unit 6C involved in the first modified example. For comparison with... Figures 1 to 25 The same elements described herein are labeled with the same reference numerals, and detailed descriptions are omitted.

[0407] The inkjet printer 1 involved in this variation, in addition to replacing... Figure 1 The inspection unit 6 shown has an inspection unit 6C, and is related to... Figure 1 The inkjet printer 1 shown is the same. However, the control unit 2 replaces it. Figure 8 The timing signal TMSIG is supplied to the inspection unit 6C during the pulse detection period, as shown in the example. Furthermore, in this modification, it is assumed that the determination of the state of the ejection section D in the second inspection mode described in the first embodiment is not performed. Therefore, in this modification, the pulse detection period signal Pcut is not used. Figure 8 The mask signal MSK is shown. However, in this modified example, the state of the ejection section D can also be determined using the second inspection mode. The following explanation focuses on the inspection unit 6C.

[0408] The inspection unit 6C includes a signal generation unit 60B, a judgment unit 64, and switches SWc1, SW11, and SW21. The signal generation unit 60B includes switches SWc1, SW11, and SW21, inverters INVc1, INVc2, INV11, INV12, INV21, and INV22, and a timing specifying circuit 65A, in addition to... Figure 7 The signal generation unit 60 shown is similar. Inverters INVc1, INVc2, INV11, INV12, INV21, and INV22 each output the inverted signal of the input signal. The determination unit 64 and... Figure 7 The same applies to the determination unit 64 shown.

[0409] The timing designation circuit 65A generates a masking signal CSIG and an endpoint designation signal ESIG based on the timing signal TMSIG supplied from the control unit 2. Then, the timing designation circuit 65A outputs the masking signal CSIG to switches SWc1, SW11, and SW21. Additionally, the timing designation circuit 65A outputs the endpoint designation signal ESIG to the adjustment unit 63.

[0410] The timing signal TMSIG is, for example, a signal that initially has a low level, transitions from a low level to a high level according to a masking timing, and then transitions from a high level to a low level according to a reset timing te that follows the masking timing. That is, the timing based on the rising edge of the timing signal TMSIG is the masking timing, and the timing based on the falling edge of the timing signal TMSIG is the reset timing tep. The masking timing can also be, for example, the timing based on the connection state specification signal Qs[j] transitioning from a high level to a low level.

[0411] The masking signal CSIG is, for example, a signal that initially has a low level and transitions from a low level to a high level triggered by the timing signal TMSIG transitioning from a low level to a high level. Furthermore, the masking signal CSIG may also transition from a high level to a low level before the start of the next unit period TU, which includes the timing signal TMSIG transitioning from a low level to a high level.

[0412] The endpoint designation signal ESIG is, for example, a signal that initially has a low level and transitions from a low level to a high level triggered by the timing signal TMSIG transitioning from a low level to a high level. Furthermore, the endpoint designation signal ESIG may also transition from a low level to a high level before the start of the control period TSS2 contained in the next unit period TU, which includes the timing of the timing signal TMSIG transitioning from a low level to a high level.

[0413] Thus, in this modified example, the masking signal CSIG and the endpoint designation signal ESIG are signals based on the timing signal TMSIG, which is input to the signal generation unit 60B via a single signal line. The endpoint designation signal ESIG is an example of a "reset signal".

[0414] Switches SWc1, SW11, and SW21 switch the conduction and non-conduction of the detection circuit 33 in the head unit 3 and the comparison unit 62 in the signal generation unit 60B based on the masking signal CSIG. For example, by opening switch SWc1, the signal path of the residual vibration signal VD from the detection circuit 33 to the comparison circuit 620 in the comparison unit 62 is masked. Similarly, by opening switch SW11, the signal path of the residual vibration signal VD from the detection circuit 33 to the comparison circuit 621 in the comparison unit 62 is masked. Furthermore, by opening switch SW21, the signal path of the residual vibration signal VD from the detection circuit 33 to the comparison circuit 622 in the comparison unit 62 is masked.

[0415] exist Figure 26In the example shown, switches SWc1, SW11, and SW21 are turned on when the shielding signal CSIG is low and turned off when the shielding signal CSIG is high. For example, when switch SWc1 is turned on, the residual vibration signal VD from detection circuit 33 is supplied to comparator circuit 620. Similarly, when switch SW11 is turned on, the residual vibration signal VD from detection circuit 33 is supplied to comparator circuit 621, and when switch SW21 is turned on, the residual vibration signal VD from detection circuit 33 is supplied to comparator circuit 622.

[0416] Switch SWc2 uses the masking signal CSIG to toggle whether the input of inverter INVc1 is connected to the output of comparator circuit 620 or the output of inverter INVc2. Figure 26 In the example shown, when the shielding signal CSIG is low, switch SWc2 connects the input of inverter INVc1 to the output of comparator circuit 620, and when the shielding signal CSIG is high, it connects the input of inverter INVc1 to the output of inverter INVc2. The output of inverter INVc1 is connected to the input of inverter INVc2. Therefore, the output of inverter INVc2 is maintained at a timing potential when the shielding signal CSIG transitions from low to high. Furthermore, the output of inverter INVc2 is connected to the input of adjustment circuit 630 in adjustment unit 63. Therefore, the input of adjustment circuit 630 is maintained at a timing potential when the shielding signal CSIG transitions from low to high.

[0417] Switch SW12 uses the masking signal CSIG to toggle whether the input of inverter INV11 is connected to the output of comparator circuit 621 or the output of inverter INV12. Figure 26 In the example shown, when the shielding signal CSIG is low, switch SW12 connects the input of inverter INV11 to the output of comparator circuit 621; when the shielding signal CSIG is high, it connects the input of inverter INV11 to the output of inverter INV12. The output of inverter INV11 is connected to the input of inverter INV12. Therefore, the output of inverter INV12 is maintained at a potential that corresponds to the timing of the transition from low to high of the shielding signal CSIG. Furthermore, the output of inverter INV12 is connected to the input of the adjustment circuit 631 in the adjustment unit 63. Therefore, the input of adjustment circuit 631 is maintained at a potential that corresponds to the timing of the transition from low to high of the shielding signal CSIG.

[0418] Switch SW22, based on the masking signal CSIG, toggles whether the input of inverter INV21 is connected to the output of comparator circuit 622 or the output of inverter INV22. Figure 26 In the example shown, when the shielding signal CSIG is low, switch SW22 connects the input of inverter INV21 to the output of comparator circuit 622; when the shielding signal CSIG is high, it connects the input of inverter INV21 to the output of inverter INV22. The output of inverter INV21 is connected to the input of inverter INV22. Therefore, the output of inverter INV22 is maintained at a potential that corresponds to the timing of the transition from low to high of the shielding signal CSIG. Furthermore, the output of inverter INV22 is connected to the input of the adjustment circuit 632 in the adjustment unit 63. Therefore, the input of adjustment circuit 632 is maintained at a potential that corresponds to the timing of the transition from low to high of the shielding signal CSIG.

[0419] Thus, in this modified example, the signal generation unit 60B, more specifically, maintains the potential of the comparison signal CPC during the blocking timing for inverters INVc1 and INVc2. Similarly, the signal generation unit 60B, more specifically, maintains the potential of the comparison signal CP1 during the blocking timing for inverters INV11 and INV12. Furthermore, the signal generation unit 60B, more specifically, maintains the potential of the comparison signal CP2 during the blocking timing for inverters INV21 and INV22.

[0420] Adjustment part 63 and Figure 7 The adjustment section 63 shown operates in the same manner. However, in Figure 26 In the adjustment unit 63 shown, the outputs of the inverters INVc2, INV12, and INV22 are input instead of the comparison signals CPC, CP1, and CP2, and the endpoint specification signal ESIG is input instead of the pulse detection period signal Pcut. Furthermore, the mask signal MSK is not used in this variant, as described above.

[0421] The adjustment circuit 630 of the adjustment unit 63 generates a comparison signal CCPc that represents the logical product of the output signal of the inverter INVc2 and the endpoint specification signal ESIG. Therefore, the comparison signal CCPc is at the level of the comparison signal CPCc during the period preceding the masking timing, and is maintained at the level of the comparison signal CCPc at the masking timing during the period from the masking timing to the reset timing tep. Furthermore, after the reset timing tep, the comparison signal CCPc is maintained at a low level. The adjustment circuits 631 and 632 of the adjustment unit 63 operate in the same manner as the adjustment circuit 630. Thus, the signal generation unit 60B generates comparison signals CCPc, CCP1, and CCP2 by maintaining the potential of the residual vibration signal VD at the masking timing.

[0422] Furthermore, the configuration of the inspection unit 6B is not limited to... Figure 26 The example shown. For example, the timing designator circuit 65A can also be located outside the signal generation unit 60B. That is, the signal generation unit 60B can also be defined as not including the timing designator circuit 65A.

[0423] For example, the adjustment circuit 630 may also include a latch circuit that changes the comparison signal CCPc from low to high when the output signal of inverter INVc2 changes from low to high, and resets the comparison signal CCPc to low when the endpoint specification signal ESIG changes from high to low. Adjustment circuits 631 and 632 may also include latch circuits. In this solution, the level of the comparison signal CP during the masking timing is maintained by the latch circuit, therefore switches SWc1, SW11, and SW21, as well as inverters INVc1, INVc2, INV11, INV12, INV21, and INV22, can be omitted.

[0424] Alternatively, for example, a latching circuit that maintains the level of the comparison signal CP during the masking timing can be used instead of switches SWc1, SW11 and SW21, and inverters INVc1, INVc2, INV11, INV12, INV21 and INV22.

[0425] Additionally, the endpoint designation signal ESIG can also be supplied to the determination unit 67 of the determination unit 64. In this embodiment, switches SWc1, SW11, and SW21, inverters INVc1, INVc2, INV11, INV12, INV21, and INV22, and adjustment circuit 630 can also be omitted. For example, in this embodiment, the determination circuit 670 of the determination unit 67 measures the time from the timing tsc when the comparison signal CPc changes from low to high to the reset timing tep when the endpoint designation signal ESIG changes from high to low, and determines the measurement result as the time length TCc. The determination circuits 671 and 672 of the determination unit 67 also operate in the same manner as the determination circuit 670.

[0426] Additionally, for example, the reset timing tep, i.e., the timing of the timing signal TMSIG changing from high to low, can also be adjusted for each nozzle N.

[0427] Furthermore, the polarities of the timing signal TMSIG, the masking signal CSIG, and the endpoint designation signal ESIG can be appropriately determined based on the characteristics of various elements such as the switch SWc1. For example, the timing signal TMSIG can also be a signal that is initially high, transitions from high to low according to the masking timing, and transitions from low to high according to the reset timing te.

[0428] In this modified example, the same effects as the above-described implementation method can also be obtained.

[0429] Furthermore, in this modified example, the signal generation unit 60B maintains the respective levels of the comparison signals CPc, CP1, and CP2 during the masking timing. Therefore, in this modified example, the time from the input of the residual vibration signal VD to the signal generation unit 60B until the masking timing can be shortened. As a result, in this modified example, the inspection time for determining the state of the ejection section D can be easily shortened.

[0430] Furthermore, in this modified example, the adjustment unit 63 of the signal generation unit 60B resets the levels of the comparison signals CCPc, CCP1, and CCP2 according to the input of the endpoint designation signal ESIG. The input of the endpoint designation signal ESIG, for example, refers to the transition of the level of the endpoint designation signal ESIG from a high level to a low level. Thus, in this modified example, the reset of the comparison signals CCPc, CCP1, and CCP2 can be controlled by the endpoint designation signal ESIG. Therefore, in this modified example, for example, compared to a scheme where the comparison signals CCPc, CCP1, and CCP2 are reset after a predetermined time has elapsed since the input of the shielding signal CSIG, the comparison signals CCPc, CCP1, and CCP2 can be easily adjusted. As a result, in this modified example, for example, compared to a scheme where the comparison signals CCPc, CCP1, and CCP2 are reset after a predetermined time has elapsed since the input of the shielding signal CSIG, the sensitivity when determining the state of the ejection unit D can be easily adjusted.

[0431] Furthermore, in this modified example, the masking signal CSIG and the endpoint designation signal ESIG are based on the timing signal TMSIG, which is input via a single signal line from the signal generation unit 60B, and more specifically from the timing designation circuit 65A. One of the masking timing and the reset timing tep is based on the rising edge of the timing signal TMSIG, and the other is based on the falling edge of the timing signal TMSIG. Thus, in this modified example, the masking timing and reset timing tep, which are mutually exclusive, are defined based on the rising and falling edges of a single timing signal TMSIG, thereby suppressing an increase in the number of signal lines and interfaces relative to the signal generation unit 60B.

[0432] Alternatively, in this modified example, when shortening the inspection time for the state of the ejector section D, the reset timing tep can be adjusted to shorten the time from the masking timing to the reset timing tep compared to a long inspection time. Thus, in this solution, the inspection time for the state of the ejector section D can be easily shortened by adjusting the reset timing tep. For example, in this solution, by shortening the time from the masking timing to the reset timing tep, the period during which the comparison signal CP is output can be shortened.

[0433] Second variation

[0434] In the above embodiments and variations, the amplitude Vamp is adjusted by adjusting the time ratio of the time lengths TCc and TC1, but the present invention is not limited to this approach. For example, the amplitude calculation circuit 68 may also calculate the amplitude Vamp by treating the threshold potential Vth1 as a correction potential that differs from the actual potential.

[0435] Specifically, in the above-described embodiments, for example, when... Figure 10 Given that the amplitude Vamp of the residual vibration signal VD shown is calculated based on the time lengths TCc and TC1, substituting "0.5" and "0" into the values... Figure 7 The threshold potentials Vth1 and VthC of equation (1) are explained in the text. In contrast, in this modified example, for example, "0" is substituted into the threshold potential VthC of equation (1), and a value that is greater than "0.5V" or smaller than the actual potential difference "0.5V" relative to the threshold potential VthC is substituted into the threshold potential Vth1. The value of the threshold potential Vth1 substituted into equation (1) is, for example, based on the value of the correction potential. The correction information of the correction potential is shown to be stored in the storage unit 5, for example. An example of "first correction information" is shown for the correction information of the correction potential used to determine the state of the ejection section D[j], and an example of "second correction information" is shown for the correction information of the correction potential used to determine the state of the ejection section D[i].

[0436] When a value larger than the actual potential difference "0.5V" relative to the threshold potential VthC is substituted into the threshold potential Vth1 in equation (1), the calculated amplitude Vamp becomes larger compared to the case where the actual potential difference "0.5V" relative to the threshold potential VthC is substituted into the threshold potential Vth1. That is, the amplitude Vamp calculated based on the time lengths TCc and TC1 becomes larger.

[0437] When a value smaller than the actual potential difference "0.5V" relative to the threshold potential VthC is substituted into the threshold potential Vth1 in equation (1), the calculated amplitude Vamp becomes smaller compared to the case where the actual potential difference "0.5V" relative to the threshold potential VthC is substituted into the threshold potential Vth1. That is, the amplitude Vamp calculated based on the time lengths TCc and TC1 becomes smaller.

[0438] Thus, in this modified example, the threshold potential Vth1, which is compared with the potential of the residual vibration signal VD to generate the comparison signal CP1, is regarded as a correction potential that differs from the actual potential, and the amplitude Vamp calculated based on the time lengths TCc and TC1 is adjusted accordingly. For example, the determination unit 64B uses the comparison signal CP1[j] as a signal indicating whether the residual vibration signal VD[j] is above the correction potential based on the correction information. The correction potential can be appropriately determined according to the adjustment amount of the amplitude Vamp. Alternatively, in this modified example, both the adjustment of the amplitude Vamp by regarding the threshold potential Vth1 as the correction potential and the adjustment of the time ratio of the time lengths TCc and TC1 can be performed.

[0439] In this modified example, the inkjet printer 1 includes: an ejection section D[j] and an ejection section D[i], capable of ejecting ink according to an input drive signal COM; a signal generation unit 60A, which, when a residual vibration signal VD[j] corresponding to the residual vibration generated in the ejection section D[j] with the input of the drive signal COM is input, generates a comparison signal CP1[j] and a comparison signal CPc[j] based on the residual vibration signal VD[j], and when a residual vibration signal VD[i] corresponding to the residual vibration generated in the ejection section D[i] with the input of the drive signal COM is input... The following steps generate comparison signals CP1[i] and CPc[i] based on the residual vibration signal VD[i]. Storage unit 5 stores first correction information for comparison signal CP1[j] and second correction information for comparison signal CP1[i]. Determination unit 64B determines the state of ejection section D[j] using the first correction information, comparison signal CP1[j], and comparison signal CPc[j] without using the second correction information, and determines the state of ejection section D[i] using the second correction information, comparison signal CP1[i], and comparison signal CPc[i] without using the first correction information. Comparison signal CPc[j] indicates whether the residual vibration signal VD[j] is above the threshold potential VthC, and comparison signal CP1[j] indicates whether the residual vibration signal VD[j] is above the threshold potential Vth1, which is different from the threshold potential VthC. The determination unit 64B uses the comparison signal CP1[j] to determine the state of the ejection unit D[j], which indicates whether the residual vibration signal VD[j] is above the correction potential based on the first correction information.

[0440] In this modified example, the same effects as the above-described embodiments and modifications can also be obtained. In addition, in this modified example, by treating the threshold potential Vth1 as a correction potential that is different from the actual potential, the adjustment waveform based on the sine wave of the comparison signal CP1[j] can be easily corrected.

[0441] Third variation

[0442] In the third embodiment described above, an example is shown where the reset timings tec, te1, and te2 are adjusted for each ejector section D; however, the present invention is not limited to this approach. For example, the reset timings tec, te1, and te2 can also be determined for each group comprising multiple ejector sections D. A group comprising multiple ejector sections D can also be, for example, a group of multiple ejector sections D corresponding to a nozzle array NL. Thus, in this modified example, the same effects as in the third embodiment described above can also be obtained.

[0443] Fourth variation

[0444] In the above embodiments and modifications, the piezoelectric element PZ is shown to be displaced in the Z1 direction by changing the potential of the independent drive signal Vin[j] from a low potential to a high potential; however, the present invention is not limited to this approach. For example, a piezoelectric element PZ that is displaced in the Z1 direction by changing the potential of the independent drive signal Vin[j] from a high potential to a low potential may also be used. In this case, for example, the potential of the drive signal COM changes from a low potential to a high potential in the portion corresponding to the expansion element and from a high potential to a low potential in the portion corresponding to the contraction element. In this modification, the same effects as in the above embodiments and modifications can also be obtained.

[0445] Fifth variation

[0446] In the above embodiments and modifications, each head unit 3 is illustrated with one nozzle row NL, but the present invention is not limited to this approach. For example, each head unit 3 may also have multiple nozzle rows NL. In this modification, the same effects as in the above embodiments and modifications can also be obtained.

[0447] Sixth variation

[0448] In the above embodiments and variations, the inkjet printer 1 is illustrated as having four head units 3, but the present invention is not limited to this configuration. For example, the inkjet printer 1 may have one or more but three head units 3, or it may have five or more head units 3. Alternatively, the inkjet printer 1 may have one or more but three head units 3A, or it may have five or more head units 3A.

[0449] Seventh variation

[0450] In the above embodiments and modifications, the amplitude Vamp is calculated based on the duration during which the potential of the residual vibration signal VD is above a threshold potential. However, the present invention is not limited to this approach. For example, the inspection unit 6 may also calculate the amplitude Vamp based on the duration during which the potential of the residual vibration signal VD is below a threshold potential. In this modification, the same effects as in the above embodiments and modifications can also be obtained.

[0451] Eighth variation

[0452] In the above embodiments and modifications, a case is illustrated where multiple inspection units 6 are provided, each corresponding one-to-one with a plurality of head units 3. However, the present invention is not limited to this approach. For example, one inspection unit 6 may be provided relative to a plurality of head units 3, or multiple inspection units 6 may be provided relative to a single head unit 3. In this modification, the same effects as in the above embodiments and modifications can also be obtained.

[0453] Ninth variation

[0454] In the above embodiments and variations, it is assumed that the inkjet printer 1 is a serial printer. However, the present invention is not limited to this approach. The inkjet printer 1 can also be a so-called line printer in which multiple nozzles N in the head module HM extend in a manner wider than the width of the recording paper P. In this variation, the same effects as in the above embodiments and variations can also be obtained.

[0455] 3. Postscript

[0456] Based on the examples above, one can grasp the following structure, for instance.

[0457] Postscript A1

[0458] Appendix A1 relates to a liquid ejection device comprising: an ejection section capable of ejecting liquid according to an input drive signal; a signal generation section receiving a residual vibration signal corresponding to residual vibration generated in the ejection section upon input of the drive signal, and generating a status check signal based on the residual vibration signal; and a determination section determining the status of the ejection section based on the status check signal. The signal generation section has: a first check mode that generates a first check mode signal corresponding to a first portion of the residual vibration signal within a first period as the status check signal; and a second check mode that generates a second check mode signal corresponding to a second portion of the residual vibration signal within a second period as the status check signal, wherein the first period is a shorter period than the second period.

[0459] According to Appendix A1, by determining the state of the ejector in the first inspection mode, the inspection time for determining the state of the ejector can be shortened, and by determining the state of the ejector in the second inspection mode, the state of the ejector can be determined with good accuracy.

[0460] Postscript A2

[0461] Note A2 relates to the liquid ejection device, which is the same liquid ejection device as Note A1, wherein the first period is less than one-quarter of the period of the residual vibration signal, and the second period is more than one-half of the period of the residual vibration signal.

[0462] According to Appendix A2, by determining the state of the ejector in the first inspection mode, compared with determining the state of the ejector in the second inspection mode, the inspection time can be reduced by more than one-quarter of the cycle of the residual vibration signal.

[0463] Postscript A3

[0464] The liquid ejection device mentioned in Appendix A3 is the liquid ejection device mentioned in Appendix A1 or Appendix A2, wherein the second period is a period later than the first period, and in the second inspection mode, the signal generation unit generates the second inspection mode signal in a manner that does not use the first part of the residual vibration signal.

[0465] According to Appendix A3, by determining the state of the ejector section in the second inspection mode, even when the residual vibration signal immediately after being input to the signal generation section is superimposed with noise, the influence of the noise on the determination of the ejector section's state can be suppressed.

[0466] Postscript A4

[0467] The liquid ejection device referred to in Appendix A4 is the liquid ejection device referred to in any one of Appendices A1 to A3, wherein the first period begins before a first time has elapsed since the residual vibration signal was input to the signal generation unit, and the first time is a time shorter than a quarter of the period of the residual vibration signal.

[0468] According to Appendix A4, in the first inspection mode, it is possible to suppress the time from the input of the residual vibration signal to the signal generation unit to the generation of the status inspection signal from becoming longer.

[0469] Postscript A5

[0470] Appendix A5 relates to a head unit control circuit that controls a head unit having a jetting section capable of ejecting liquid according to an input drive signal. It includes: a signal generation unit that receives a residual vibration signal corresponding to residual vibration generated in the jetting section with the input of the drive signal and generates a state check signal based on the residual vibration signal; and a determination unit that determines the state of the jetting section based on the state check signal. The signal generation unit has: a first check mode that generates a first check mode signal corresponding to a first portion of the residual vibration signal within a first period as the state check signal; and a second check mode that generates a second check mode signal corresponding to a second portion of the residual vibration signal within a second period as the state check signal, wherein the first period is shorter than the second period.

[0471] According to note A5, the same effect as that of note A1 above can be obtained.

[0472] Postscript A6

[0473] Note A6 relates to the head unit control circuit, which is the same as the head unit control circuit in Note A5, wherein the first period is less than one-quarter of the period of the residual vibration signal, and the second period is more than one-half of the period of the residual vibration signal.

[0474] According to note A6, the same effect as that of note A2 above can be obtained.

[0475] Postscript A7

[0476] Note A7 relates to the head unit control circuit, which is the same as the head unit control circuit in Note A5 or Note A6, wherein the second period is a period later than the first period, and in the second inspection mode, the signal generation unit generates the second inspection mode signal in a manner that does not use the first part of the residual vibration signal.

[0477] According to note A7, the same effect as that of note A3 above can be obtained.

[0478] Postscript A8

[0479] The liquid ejection device mentioned in Appendix A8 is the head unit control circuit mentioned in any one of Appendices A5 to A7, wherein the first period begins before a first time has elapsed since the residual vibration signal was input to the signal generation unit, and the first time is a time shorter than a quarter of the period of the residual vibration signal.

[0480] According to note A8, the same effect as that of note A4 above can be obtained.

[0481] Postscript A9

[0482] Appendix A9 relates to a liquid ejection inspection method for a liquid ejection device having an ejection section capable of ejecting liquid according to an input drive signal. This method generates a status inspection signal based on a residual vibration signal corresponding to residual vibration generated in the ejection section with the input of the drive signal. The status of the ejection section is determined based on the status inspection signal. When a first inspection mode is selected as the inspection mode for determining the status of the ejection section, a first inspection mode signal corresponding to a first portion of the residual vibration signal within a first period is generated as the status inspection signal. When a second inspection mode is selected as the inspection mode, a second inspection mode signal corresponding to a second portion of the residual vibration signal within a second period is generated as the status inspection signal. The first period is a shorter period than the second period.

[0483] According to note A9, the same effect as that of note A1 above can be obtained.

[0484] Postscript A10

[0485] The liquid ejection inspection method described in Note A10 is the same as the liquid ejection inspection method described in Note A9, wherein the first period is less than one-quarter of the period of the residual vibration signal, and the second period is more than one-half of the period of the residual vibration signal.

[0486] According to note A10, the same effect as note A2 above can be obtained.

[0487] Postscript A11

[0488] The liquid ejection inspection method described in Appendix A11 is the liquid ejection inspection method described in Appendix A9 or Appendix A10, wherein the second period is a period later than the first period, and in the second inspection mode, the second inspection mode signal is generated in a manner that does not use the first portion of the residual vibration signal.

[0489] According to note A11, the same effect as that of note A3 above can be obtained.

[0490] Note A12

[0491] The liquid ejection inspection method described in Appendix A12 is the liquid ejection inspection method described in any one of Appendices A9 to A11, wherein the first period begins before a first time elapses after the input of the drive signal to the ejection part ends, and the first time is a time shorter than a quarter of the period of the residual vibration signal.

[0492] According to note A12, the same effect as that of note A4 above can be obtained.

[0493] Postscript B1

[0494] Appendix B1 relates to a liquid ejection device comprising: an ejection section capable of ejecting liquid according to an input drive signal; a signal generation section receiving a residual vibration signal corresponding to residual vibration generated in the ejection section with the input of the drive signal, and generating a plurality of inspection signals based on the residual vibration signal; and a determination section determining the state of the ejection section, wherein the signal path of the residual vibration signal from the ejection section to the signal generation section is blocked at a blocking timing based on a blocking signal, and the determination section determines the state of the ejection section based on a plurality of inspection signal information generated by using the plurality of inspection signals as signals that have been reset at a reset timing based on a reset signal, wherein when the blocking timing is earlier than the reset timing, each of the plurality of inspection signal information is generated by using each of the plurality of inspection signals as a potential maintained at the blocking timing until the reset timing.

[0495] According to Appendix B1, by extending the time from the start of the supply of the residual vibration signal to the signal generation unit to the reset time, the inspection time for determining the state of the ejection unit can also be shortened.

[0496] Note B2

[0497] The liquid ejection device described in Appendix B2 is the same as the liquid ejection device described in Appendix B1, wherein the signal generation unit maintains the potential of each of the plurality of inspection signals at the time of the shielding timing.

[0498] According to Appendix B2, the time from when the residual vibration signal is input to the signal generation unit to the masking timing can be shortened.

[0499] Postscript B3

[0500] The liquid ejection device mentioned in Appendix B3 is the liquid ejection device mentioned in Appendix B1 or Appendix B2, wherein the signal generation unit resets the potential of each of the plurality of inspection signals according to the input of the reset signal.

[0501] According to note B3, multiple inspection signals can be easily adjusted.

[0502] Postscript B4

[0503] The liquid ejection device mentioned in Appendix B4 is any one of the liquid ejection devices mentioned in Appendix B1 to Appendix B3, wherein the shielding signal and the reset signal are signals based on a timing signal input to the signal generation unit through a signal line, one of the shielding timing and the reset timing is based on the rising edge of the timing signal, and the other of the shielding timing and the reset timing is based on the falling edge of the timing signal.

[0504] According to Appendix B4, it is possible to suppress the increase in the number of signal lines and interfaces relative to the signal generation unit.

[0505] Postscript B5

[0506] Note B5 refers to the liquid ejection device that is involved in any one of the notes B1 to B4. When the inspection time of the state of the ejection part is shortened, the reset timing is adjusted to shorten the time from the shielding timing to the reset timing compared to the case where the inspection time is long.

[0507] According to note B5, the time between the output of multiple inspection signals can be shortened.

[0508] Postscript B6

[0509] Note B6 relates to the liquid ejection device, which is the liquid ejection device referred to in any one of Notes B1 to B5, wherein, in order to improve the inspection accuracy of the state of the ejection part, the reset timing is adjusted so that the time from the shielding timing to the reset timing is longer compared with the case of low inspection accuracy.

[0510] According to note B6, increased resolution improves inspection accuracy.

[0511] Postscript B7

[0512] The liquid ejection device mentioned in Appendix B7 is the liquid ejection device mentioned in any one of Appendices B1 to B6, wherein the signal generation unit generates the plurality of inspection signals based on a signal in a portion of a first period less than one-quarter of the period of the residual vibration signal.

[0513] According to Appendix B7, the time spent generating multiple inspection signals can be shortened, thus reducing the inspection time for determining the state of the ejection section.

[0514] Postscript B8

[0515] Note B8 refers to the liquid ejection device that is involved in any one of the notes B1 to B7, and the signal generation unit is not electrically connected to the ejection unit by the shielding signal.

[0516] According to Appendix B8, the ejector can perform other actions before the determination of the ejector's state is completed.

[0517] Postscript B9

[0518] The liquid ejection device referred to in Appendix B9 is the liquid ejection device referred to in any one of Appendices B1 to B8, wherein the plurality of inspection signals are generated based on a portion of a first period less than one-quarter of the period of the residual vibration signal, the first period starting before a first time elapses from the input of the residual vibration signal to the signal generation unit, the first time being shorter than the time corresponding to one-quarter of the period of the residual vibration signal.

[0519] According to Appendix B9, it is possible to suppress the increase in time from when the residual vibration signal is input to the signal generation unit to when multiple inspection signals are generated.

[0520] Postscript B10

[0521] Appendix B10 relates to a head unit control circuit that controls a head unit having a jetting section capable of ejecting liquid according to an input drive signal. It includes: a signal generation unit that receives a residual vibration signal corresponding to residual vibration generated in the jetting section with the input of the drive signal and generates multiple inspection signals based on the residual vibration signal; and a determination unit that determines the state of the jetting section. The signal path of the residual vibration signal from the jetting section to the signal generation unit is masked at a masking timing based on a masking signal. The determination unit determines the state of the jetting section based on multiple inspection signal information generated by using the multiple inspection signals as signals that have been reset at a reset timing based on a reset signal. If the masking timing is earlier than the reset timing, each of the multiple inspection signal information is generated by using each of the multiple inspection signals as a potential maintained at the masking timing until the reset timing.

[0522] According to note B10, the same effect as that of note B1 above can be obtained.

[0523] Postscript B11

[0524] Note B11 relates to the head unit control circuit, which is the same as the head unit control circuit in Note B10, wherein the signal generation unit maintains the potential of each of the plurality of check signals during the masking timing.

[0525] According to note B11, the same effect as that of note B2 above can be obtained.

[0526] Postscript B12

[0527] Note B12 relates to the head unit control circuit, which is the same as the head unit control circuit in Note B10 or Note B11, wherein the signal generation unit resets the potential of each of the plurality of check signals according to the input of the reset signal.

[0528] According to note B12, the same effect as that of note B3 mentioned above can be obtained.

[0529] Postscript B13

[0530] Note B13 relates to the head unit control circuit, which is the head unit control circuit of any one of Notes B10 to B12, wherein the masking signal and the reset signal are signals based on a timing signal input to the signal generation unit through a signal line, one of the masking timing and the reset timing is based on the rising edge of the timing signal, and the other of the masking timing and the reset timing is based on the falling edge of the timing signal.

[0531] According to note B13, the same effect as that of note B4 above can be obtained.

[0532] Postscript B14

[0533] Note B14 relates to the head unit control circuit, which is the head unit control circuit of any one of Notes B10 to B13, wherein, when the inspection time of the state of the ejection section is shortened, the reset timing is adjusted to shorten the time from the shielding timing to the reset timing compared to the case where the inspection time is long.

[0534] According to note B14, the same effect as that of note B5 above can be obtained.

[0535] Postscript B15

[0536] Note B15 relates to the head unit control circuit, which is the head unit control circuit of any one of Notes B10 to B14, wherein, in order to improve the inspection accuracy of the state of the ejection section, the reset timing is adjusted to make the time from the shielding timing to the reset timing longer compared to the case of low inspection accuracy.

[0537] According to note B15, the same effect as that of note B6 above can be obtained.

[0538] Postscript B16

[0539] The head unit control circuit mentioned in Appendix B16 is the head unit control circuit mentioned in any one of Appendices B10 to B15, wherein the signal generation unit generates the plurality of inspection signals based on the signal in a portion of a first period less than one-quarter of the period of the residual vibration signal.

[0540] According to note B16, the same effect as that of note B7 above can be obtained.

[0541] Postscript B17

[0542] The head unit control circuit mentioned in Appendix B17 is the head unit control circuit mentioned in any one of Appendices B10 to B16, wherein the signal generation unit is not electrically connected to the ejection unit by the shielding signal.

[0543] According to note B17, the same effect as that of note B8 above can be obtained.

[0544] Postscript B18

[0545] The head unit control circuit mentioned in Appendix B18 is the head unit control circuit mentioned in any one of Appendices B10 to B17, wherein the plurality of inspection signals are generated based on a portion of a first period less than one-quarter of the period of the residual vibration signal, the first period starting before a first time elapses from the input of the residual vibration signal to the signal generation unit, the first time being shorter than the time corresponding to one-quarter of the period of the residual vibration signal.

[0546] According to note B18, the same effect as that of note B9 above can be obtained.

[0547] Postscript B19

[0548] Appendix B19 relates to a liquid ejection inspection method for a liquid ejection device having an ejection section capable of ejecting liquid according to an input drive signal. In this method, a residual vibration signal corresponding to residual vibration generated in the ejection section with the input of the drive signal is input. Multiple inspection signals are generated based on the residual vibration signals. The state of the ejection section is determined based on multiple inspection signal information generated by using the multiple inspection signals as signals that have been reset according to a reset timing based on a reset signal. The signal path of the residual vibration signal output from the ejection section is blocked according to a blocking timing based on a blocking signal. When the blocking timing is earlier than the reset timing, each of the multiple inspection signal information is generated by using each of the multiple inspection signals as a signal whose potential at the blocking timing is maintained until the reset timing.

[0549] According to note B19, the same effect as that of note B1 above can be obtained.

[0550] Postscript B20

[0551] Appendix B20 relates to a liquid ejection inspection method, and Appendix B19 relates to a liquid ejection inspection method, wherein the potentials of the plurality of inspection signals are maintained at the time of the shielding.

[0552] According to note B20, the same effect as that of note B2 above can be obtained.

[0553] Postscript B21

[0554] The liquid ejection inspection method described in Appendix B21 is the liquid ejection inspection method described in Appendix B19 or Appendix B20, wherein the potentials of the plurality of inspection signals are reset according to the input of the reset signal.

[0555] According to note B21, the same effect as that of note B3 above can be obtained.

[0556] Postscript B22

[0557] The liquid ejection inspection method described in Appendix B22 is the liquid ejection inspection method described in any one of Appendices B19 to B21, wherein the shielding signal and the reset signal are signals based on a timing signal supplied by a signal line, one of the shielding timing and the reset timing is based on the rising edge of the timing signal, and the other of the shielding timing and the reset timing is based on the falling edge of the timing signal, and the shielding timing is a timing that precedes the reset timing.

[0558] According to note B22, the same effect as that of note B4 above can be obtained.

[0559] Postscript B23

[0560] The liquid ejection inspection method involved in Appendix B23 is the liquid ejection inspection method involved in any one of Appendices B19 to B22, wherein, when shortening the inspection time of the state of the ejection part, the reset timing is adjusted to shorten the time from the shielding timing to the reset timing compared to the case where the inspection time is long.

[0561] According to note B23, the same effect as that of note B5 above can be obtained.

[0562] Postscript B24

[0563] The liquid ejection inspection method involved in Appendix B24 is a liquid ejection inspection method involved in any one of Appendices B19 to B23, wherein, in order to improve the inspection accuracy of the state of the ejection part, the reset timing is adjusted so that the time from the shielding timing to the reset timing is longer compared with the case of low inspection accuracy.

[0564] According to note B24, the same effect as that of note B6 above can be obtained.

[0565] Postscript B25

[0566] The liquid ejection inspection method described in Appendix B25 is the liquid ejection inspection method described in any one of Appendices B19 to B24, wherein the plurality of inspection signals are generated based on a signal in a portion of a first period less than one-quarter of the period of the residual vibration signal.

[0567] According to note B25, the same effect as that of note B7 above can be obtained.

[0568] Postscript B26

[0569] Note B26 relates to a liquid ejection inspection method, which is also related to any one of notes B19 to B25, wherein the signal path includes a first signal path and a second signal path, and the first signal path is set to be not electrically connected to the second signal path according to the shielding signal.

[0570] According to note B26, the same effect as that of note B8 mentioned above can be obtained.

[0571] Postscript B27

[0572] The liquid ejection inspection method described in Appendix B27 is the liquid ejection inspection method described in any one of Appendices B19 to B26, wherein the plurality of inspection signals are generated based on a portion of a first period less than one-quarter of the period of the residual vibration signal, the first period starting before a first time elapses after the end of the input of the drive signal to the ejection part, the first time being shorter than the time corresponding to one-quarter of the period of the residual vibration signal.

[0573] According to note B27, the same effect as that of note B9 above can be obtained.

[0574] Postscript C1

[0575] Appendix C1 relates to a liquid ejection device comprising: a first ejection section and a second ejection section, capable of ejecting liquid according to an input drive signal; a signal generation section, which generates a first check signal and a first reference signal based on the first residual vibration signal when a first residual vibration signal corresponding to residual vibration generated in the first ejection section with the input of the drive signal is input, and generates a second check signal and a second reference signal based on the second residual vibration signal when a second residual vibration signal corresponding to residual vibration generated in the second ejection section with the input of the drive signal is input; a determination section, which determines the state of the first ejection section and the second ejection section respectively; and a storage section. The storage unit stores first calibration information and second calibration information. The determination unit determines the state of the first ejection unit by using first inspection signal information generated based on the first calibration information and the first inspection signal, without using the second calibration information, and by using first reference signal information generated based on the first reference signal, without using the first calibration information and the second calibration information. The determination unit determines the state of the second ejection unit by using second inspection signal information generated based on the second calibration information and the second inspection signal, without using the first calibration information and the second calibration information, and by using second reference signal information generated based on the second reference signal, without using the first calibration information and the second calibration information.

[0576] According to Note C1, the condition of the ejector section can be checked efficiently, thus preventing the inspection time for determining the condition of the ejector section from becoming longer.

[0577] Postscript C2

[0578] The liquid ejection device mentioned in Appendix C2 is the same as the liquid ejection device mentioned in Appendix C1. In this device, the first inspection signal information is generated based on information that the first inspection signal has been corrected using the first correction information, and the second inspection signal information is generated based on information that the second inspection signal has been corrected using the second correction information. When the amount of liquid ejected from the second ejection part is less than the amount of liquid ejected from the first ejection part, the correction amount using the second correction information is greater than the correction amount using the first correction information.

[0579] According to Appendix C2, the first ejector section and the second ejector section can be inspected using the same reference.

[0580] Postscript C3

[0581] Appendix C3 relates to a liquid ejection device comprising: a first ejection section and a second ejection section, capable of ejecting liquid according to an input drive signal; a signal generation section, which generates a first check signal and a first reference signal based on the first residual vibration signal when a first residual vibration signal corresponding to residual vibration generated in the first ejection section with the input of the drive signal is input, and generates a second check signal and a second reference signal based on the second residual vibration signal when a second residual vibration signal corresponding to residual vibration generated in the second ejection section with the input of the drive signal is input; a storage section, which stores first correction information for the first check signal and second correction information for the second check signal; and a determination section, which does not... The state of the first ejector is determined by using the second correction information and the first correction information, the first check signal, and the first reference signal. The state of the second ejector is determined by using the second correction information, the second check signal, and the second reference signal without using the first correction information. The first reference signal is a signal indicating whether the first residual vibration signal is above a first potential. The first check signal is a signal indicating whether the first residual vibration signal is above a second potential different from the first potential. The determination unit uses the first check signal as a signal indicating whether the first residual vibration signal is above a third potential based on the first correction information to determine the state of the first ejector.

[0582] According to note C3, the same effect as that described in note C1 can be obtained. Furthermore, according to note C3, by treating the second potential as a third potential different from the actual potential, the adjustment waveform based on the sine wave of the first check signal can be easily corrected.

[0583] Postscript C4

[0584] The liquid ejection device referred to in Appendix C4 is the liquid ejection device referred to in any one of Appendices C1 to C3, wherein the first reference signal is a signal indicating whether the first residual vibration signal is above a first potential, the first check signal is a signal indicating whether the first residual vibration signal is above a second potential different from the first potential, and the first check signal information is information generated by using the first check signal as a signal that indicates the first residual vibration signal is above the second potential before a first timing corresponding to the first correction information, regardless of whether the first residual vibration signal changes to be below the second potential.

[0585] According to Appendix C4, by extending the time from the start of the supply of the residual vibration signal to the signal generation unit to the first timing, the inspection time for determining the state of the first ejection unit can also be shortened.

[0586] Postscript C5

[0587] Note C5 relates to the liquid ejection device, which is the liquid ejection device referred to in any one of Notes C1 to C4. In this device, the signal path of the first residual vibration signal from the first ejection section to the signal generation section is masked according to the masking timing based on the masking signal. The determination section uses the first inspection signal as a signal that has been reset according to the first timing corresponding to the first correction information, thereby generating the first inspection signal information. In the case where the masking timing is earlier than the first timing, the first inspection signal information is generated by using the first inspection signal as a signal whose potential at the masking timing is maintained until the first timing.

[0588] According to Appendix C5, by extending the time from the start of the supply of the residual vibration signal to the signal generation unit to the first timing, the inspection time for determining the state of the first ejection unit can also be shortened.

[0589] Postscript C6

[0590] The liquid ejection device referred to in Appendix C6 is the liquid ejection device referred to in any one of Appendices C1 to C5, wherein the signal generation unit generates the first inspection signal and the first reference signal based on the signal in the first residual vibration signal, which is a portion of a first period less than one-quarter of the period of the first residual vibration signal.

[0591] According to Appendix C6, the time spent generating the first inspection signal and the first reference signal can be shortened, thus shortening the inspection time for determining the state of the first ejection section.

[0592] Postscript C7

[0593] Note C7 relates to the liquid ejection device, which is the same as the liquid ejection device in Note C5, wherein the signal generation unit is not electrically connected to the first ejection unit by means of the shielding signal.

[0594] According to Appendix C7, the first ejector can perform other actions before the determination of the state of the first ejector is completed. Furthermore, according to Appendix C7, the second ejector, which is the object of the determination, can operate before the determination of the state of the first ejector is completed.

[0595] Postscript C8

[0596] The liquid ejection device referred to in Appendix C8 is the liquid ejection device referred to in any one of Appendices C1 to C7, wherein the first inspection signal and the first reference signal are generated based on a portion of a first period less than one-quarter of the period of the first residual vibration signal, the first period starting before a first time elapses from when the first residual vibration signal is input to the signal generation unit, the first time being shorter than the time corresponding to one-quarter of the period of the first residual vibration signal.

[0597] According to note C8, it is possible to suppress the time from when the residual vibration signal is input to the signal generation unit to when the first inspection signal and the first reference signal are generated from becoming longer.

[0598] Postscript C9

[0599] Note C9 relates to a head unit control circuit that controls a head unit having a first ejection section and a second ejection section capable of ejecting liquid according to an input drive signal. The head unit control circuit includes: a signal generation unit that generates a first check signal and a first reference signal based on the first residual vibration signal when a first residual vibration signal corresponding to residual vibration generated in the first ejection section with the input of the drive signal is input; and generates a second check signal and a second reference signal based on the second residual vibration signal when a second residual vibration signal corresponding to residual vibration generated in the second ejection section with the input of the drive signal is input; and a determination unit that determines whether the first ejection section and the second ejection section... The system includes a state of each ejector section and a storage section storing first correction information and second correction information. The determination section determines the state of the first ejector section by using first inspection signal information generated based on the first correction information and the first inspection signal, and by using first reference signal information generated based on the first reference signal, without using the second correction information. The determination section determines the state of the second ejector section by using second inspection signal information generated based on the second correction information and the second inspection signal, and by using second reference signal information generated based on the second reference signal, without using the first correction information and the second correction information.

[0600] According to note C9, the same effect as that of note C1 above can be obtained.

[0601] Postscript C10

[0602] Note C10 relates to the head unit control circuit, which is the same as Note C9. In this circuit, the first check signal information is generated based on information that the first check signal has been corrected using the first correction information, and the second check signal information is generated based on information that the second check signal has been corrected using the second correction information. When the amount of liquid ejected from the second ejector is less than the amount of liquid ejected from the first ejector, the correction amount using the second correction information is greater than the correction amount using the first correction information.

[0603] According to note C10, the same effect as note C2 above can be obtained.

[0604] Postscript C11

[0605] Note C11 relates to a head unit control circuit that controls a head unit having a first ejection section and a second ejection section capable of ejecting liquid according to an input drive signal. The head unit includes: a signal generation unit that generates a first check signal and a first reference signal based on the first residual vibration signal when a first residual vibration signal corresponding to residual vibration generated in the first ejection section with the input of the drive signal is input; and generates a second check signal and a second reference signal based on the second residual vibration signal when a second residual vibration signal corresponding to residual vibration generated in the second ejection section with the input of the drive signal is input; and a storage unit that stores first correction information for the first check signal and second correction information for the second check signal. The system includes a correction information unit and a determination unit. The first correction information, the first inspection signal, and the first reference signal are used to determine the state of the first ejector section without using the second correction information. The second correction information, the second inspection signal, and the second reference signal are used to determine the state of the second ejector section without using the first correction information. The first reference signal indicates whether the first residual vibration signal is at or above a first potential. The first inspection signal indicates whether the first residual vibration signal is at or above a second potential different from the first potential. The determination unit uses the first inspection signal as a signal indicating whether the first residual vibration signal is at or above a third potential based on the first correction information to determine the state of the first ejector section.

[0606] According to note C11, the same effect as note C3 above can be obtained.

[0607] Postscript C12

[0608] Note C12 relates to the head unit control circuit, which is the head unit control circuit referred to in any one of Notes C9 to C11, wherein the first reference signal is a signal indicating whether the first residual vibration signal is above a first potential, the first check signal is a signal indicating whether the first residual vibration signal is above a second potential different from the first potential, and the first check signal information is information generated by using the first check signal as a signal that indicates the first residual vibration signal is above the second potential before a first timing corresponding to the first correction information, regardless of whether the first residual vibration signal changes to be below the second potential.

[0609] According to note C12, the same effect as note C4 above can be obtained.

[0610] Postscript C13

[0611] The head unit control circuit mentioned in Appendix C13 is the head unit control circuit mentioned in any one of Appendices C9 to C12, wherein the signal path of the first residual vibration signal from the first ejection part to the signal generation part is blocked according to the blocking timing based on the blocking signal, and the determination part generates the first check signal information by using the first check signal as a signal that has been reset according to the first timing corresponding to the first correction information. When the blocking timing is a timing earlier than the first timing, the first check signal information is generated by using the first check signal as a signal whose potential at the blocking timing is maintained until the first timing.

[0612] According to note C13, the same effect as note C5 above can be obtained.

[0613] Postscript C14

[0614] The head unit control circuit involved in Appendix C14 is the head unit control circuit involved in any one of Appendices C9 to C13, wherein the signal generation unit generates the first check signal and the first reference signal based on the signal in the first residual vibration signal, which is a portion of a first period less than one-quarter of the period of the first residual vibration signal.

[0615] According to note C14, the same effect as note C6 above can be obtained.

[0616] Postscript C15

[0617] Note C15 relates to the head unit control circuit, which is the same as the head unit control circuit in Note C13, wherein the signal generation unit is not electrically connected to the first ejection unit by means of the shielding signal.

[0618] According to note C15, the same effect as note C7 above can be obtained.

[0619] Note C16

[0620] The head unit control circuit mentioned in Appendix C16 is the head unit control circuit mentioned in any one of Appendices C9 to C15, wherein the first check signal and the first reference signal are generated based on a portion of a first period less than one-quarter of the period of the first residual vibration signal, the first period starting before a first time elapses from when the first residual vibration signal is input to the signal generation unit, the first time being shorter than the time corresponding to one-quarter of the period of the first residual vibration signal.

[0621] According to note C16, the same effect as note C8 above can be obtained.

[0622] Postscript C17

[0623] Appendix C17 relates to a liquid ejection inspection method. This method includes a liquid ejection device capable of ejecting liquid from a first ejection section and a second ejection section according to an input drive signal. Specifically, a first inspection signal and a first reference signal are generated based on a first residual vibration signal corresponding to residual vibration generated in the first ejection section with the input of the drive signal. A second inspection signal and a second reference signal are generated based on a second residual vibration signal corresponding to residual vibration generated in the second ejection section with the input of the drive signal. The state of the first ejection section is determined using first inspection signal information generated based on the first correction information and the first inspection signal, and first reference signal information generated based on the first reference signal, without using the second correction information from the first correction information and the second correction information stored in the storage unit. The state of the second ejection section is determined using second inspection signal information generated based on the second correction information and the second inspection signal, and second reference signal information generated based on the second reference signal, without using the first correction information and the second correction information.

[0624] According to note C17, the same effect as that of note C1 above can be obtained.

[0625] Postscript C18

[0626] Appendix C18 relates to a liquid ejection inspection method, and Appendix C17 relates to a liquid ejection inspection method, wherein the first inspection signal information is generated based on information that the first inspection signal has been corrected using the first correction information, and the second inspection signal information is generated based on information that the second inspection signal has been corrected using the second correction information. When the amount of liquid ejected from the second ejection part is less than the amount of liquid ejected from the first ejection part, the correction amount using the second correction information is greater than the correction amount using the first correction information.

[0627] According to note C18, the same effect as note C2 above can be obtained.

[0628] Postscript C19

[0629] Appendix C19 relates to a liquid ejection inspection method comprising a liquid ejection device capable of ejecting liquid from a first ejection section and a second ejection section according to an input drive signal. In this method, a first inspection signal and a first reference signal are generated based on a first residual vibration signal corresponding to residual vibration generated in the first ejection section upon input of the drive signal. A second inspection signal and a second reference signal are generated based on a second residual vibration signal corresponding to residual vibration generated in the second ejection section upon input of the drive signal. The state of the first ejection section is determined using the first correction information, the first inspection signal, and the first reference signal, without using the second correction information from the first correction information and the second correction information stored in the storage unit. The state of the second ejection section is determined using the second correction information, the second inspection signal, and the second reference signal, without using the first correction information. The first reference signal indicates whether the first residual vibration signal is at or above a first potential. The first inspection signal indicates whether the first residual vibration signal is at or above a second potential different from the first potential. When determining the state of the first ejection section, the first inspection signal is used as a signal indicating whether the first residual vibration signal is at or above a third potential based on the first correction information to determine the state of the first ejection section.

[0630] According to note ...

Claims

1. A liquid ejection device, characterized in that, have: The ejector section is capable of ejecting liquid according to the input drive signal; A signal generation unit receives a residual vibration signal corresponding to the residual vibration generated at the ejection section as the driving signal is input, and generates a status check signal based on the residual vibration signal; and The determination unit determines the state of the ejection unit based on the state check signal. The signal generation unit has: The first inspection mode is a first inspection mode signal generated as the state inspection signal, corresponding to a first portion of the signal within a first period in the residual vibration signal. as well as The second inspection mode is a second inspection mode signal generated as the state inspection signal, corresponding to the second portion of the signal within the second period of the residual vibration signal. The first period is shorter than the second period.

2. The liquid ejection device according to claim 1, characterized in that, The first period is less than one-quarter of the period of the residual vibration signal. The second period is a period of more than half the period of the residual vibration signal.

3. The liquid ejection device according to claim 1, characterized in that, The second period is a period that follows the first period. In the second inspection mode, the signal generation unit generates the second inspection mode signal in a manner that does not use the first portion of the residual vibration signal.

4. The liquid ejection device according to claim 1, characterized in that, The first period begins before a first time elapses from the time the residual vibration signal is input to the signal generation unit. The first time is a time shorter than one-quarter of the period of the residual vibration signal.

5. A head unit control circuit, characterized in that, It is a head unit control circuit that controls a head unit equipped with an ejector section capable of ejecting liquid according to an input drive signal. The head unit control circuit includes: A signal generation unit receives a residual vibration signal corresponding to the residual vibration generated at the ejection section as the driving signal is input, and generates a status check signal based on the residual vibration signal; and The determination unit determines the state of the ejection unit based on the state check signal. The signal generation unit has: The first inspection mode is a first inspection mode signal generated as the state inspection signal, corresponding to a first portion of the signal within a first period in the residual vibration signal. as well as The second inspection mode is a second inspection mode signal generated as the state inspection signal, corresponding to the second portion of the signal within the second period of the residual vibration signal. The first period is shorter than the second period.

6. The head unit control circuit according to claim 5, characterized in that, The first period is less than one-quarter of the period of the residual vibration signal. The second period is a period of more than half the period of the residual vibration signal.

7. The head unit control circuit according to claim 5, characterized in that, The second period is a period that follows the first period. In the second inspection mode, the signal generation unit generates the second inspection mode signal in a manner that does not use the first portion of the residual vibration signal.

8. The head unit control circuit according to claim 5, characterized in that, The first period begins before a first time elapses from the time the residual vibration signal is input to the signal generation unit. The first time is a time shorter than one-quarter of the period of the residual vibration signal.

9. A method for inspecting liquid ejection, characterized in that, This is a liquid ejection inspection method for a liquid ejection device equipped with an ejection section capable of ejecting liquid according to an input drive signal. A status check signal is generated based on a residual vibration signal corresponding to the residual vibration generated at the ejection section with the input of the drive signal. The state of the ejector is determined based on the state check signal. When the first inspection mode is selected as the inspection mode for determining the state of the ejection section, a first inspection mode signal corresponding to the first portion of the signal within the first period of the residual vibration signal is generated as the state inspection signal. When the second inspection mode is selected as the inspection mode, a second inspection mode signal corresponding to the second portion of the signal within the second period of the residual vibration signal is generated as the state inspection signal. The first period is shorter than the second period.

10. The liquid ejection inspection method according to claim 9, characterized in that, The first period is less than one-quarter of the period of the residual vibration signal. The second period is a period of more than half the period of the residual vibration signal.

11. The liquid ejection inspection method according to claim 9, characterized in that, The second period is a period that follows the first period. In the second inspection mode, the second inspection mode signal is generated in a manner that does not use the first portion of the residual vibration signal.

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