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

Abstract

The invention relates to a liquid ejection apparatus, a head unit control circuit, and a liquid ejection inspection method. Provided is a liquid ejecting apparatus that shortens an inspection time for determining the state of an ejecting section (D). An inkjet printer (1) is provided with: a signal generation unit (60A) that generates a plurality of comparison signals on the basis of a residual vibration signal corresponding to residual vibration generated in an ejection unit as a drive signal is input; and a determination unit that determines a state of the ejection unit, in which a signal path of the residual vibration signal from the ejection unit to the signal generation unit is blocked at a blocking timing, and that determines the state of the ejection unit on the basis of the plurality of pieces of time information. The plurality of pieces of time information are generated by using the plurality of comparison signals as signals to be reset at a reset timing based on the reset information, and when the blocking timing is a timing before the reset timing, the signal is held up to the reset timing by using the potential when each of the plurality of comparison signals is used as the blocking timing. Each of the plurality of time information is generated.

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 by driving the ejection section of the liquid ejection head during each of a plurality of unit periods specified 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. To address this, techniques for checking the ejection state in the ejection section have been proposed in the past. For example, Patent Document 1 discloses a technique for checking the ejection state in the ejection section based on a detection signal representing the vibration remaining in the ejection section after it is driven by a drive signal.

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

[0004] However, according to existing technology, when inspecting the ejection state in the ejection section, noise is superimposed on the signal immediately after the inspection begins. Therefore, measures based on shielding circuits are taken into account the impact of this noise. From the perspective of improving inspection accuracy, this shielding circuit-based measure is quite effective, but it becomes the main reason for the increased inspection time. Furthermore, when inspecting the ejection state, for example, after the shield is removed, periodicity index data representing the period of the detection signal indicating residual vibration is generated, and information for at least one cycle of the detection signal is required. The requirement for information for one cycle of the detection signal after the shield is removed also becomes a major constraint on shortening the inspection time. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the liquid ejection device according to 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 a 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, the determination section determining the state of the ejection section based on a plurality of inspection signal information, wherein the plurality of inspection signal information is generated by using the plurality of inspection signals as signals for resetting at a reset timing based on a reset signal, and wherein, if the blocking timing is a timing 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 signal whose potential at the blocking timing is maintained until the reset timing.

[0006] Furthermore, the head unit control circuit involved in this invention is 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 plurality of check signals based on the residual vibration signal; and a determination unit that determines the state of the jetting section, wherein the signal path of the residual vibration signal from the jetting section to the signal generation unit is blocked at a blocking timing based on a blocking signal. The determination unit determines the state of the jetting section based on the plurality of check signal information, wherein the plurality of check signal information is generated by using the plurality of check signals as signals to reset at a reset timing based on a reset signal. In the case where the blocking timing is earlier than the reset timing, each of the plurality of check signal information is generated by using each of the plurality of check signals as a signal whose potential at the blocking timing is maintained until the reset timing.

[0007] Furthermore, the liquid ejection inspection method of the present invention is a liquid ejection device equipped with an ejection section capable of ejecting liquid according to an input drive signal. The method involves inputting a residual vibration signal corresponding to residual vibration generated in the ejection section with the input of the drive signal, generating multiple inspection signals based on the residual vibration signal, and determining the state of the ejection section based on the multiple inspection signal information. The multiple inspection signal information is generated by using the multiple inspection signals as signals to be reset at a reset timing based on a reset signal. The signal path of the residual vibration signal output from the ejection section is blocked at a blocking timing based on a blocking signal. If 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. Attached Figure Description

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

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

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

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

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

[0013] Figure 6 This is a block diagram illustrating an example of the configuration 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 given 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 duration.

[0019] Figure 12 It is an explanatory diagram used to illustrate the relationship between reset timing and amplitude and the 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 the 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 21 This is an explanatory diagram used to illustrate the relationship between reset timing and amplitude calculated based on duration.

[0029] Figure 22 It is an explanatory diagram used to illustrate the relationship between the time ratio of two durations 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 based on the amplitude calculated from the duration.

[0031] Figure 24 This is an illustrative diagram used to illustrate an example of amplitude calculated based on a change in the time ratio of two durations.

[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 modified example.

[0034] Explanation of reference numerals in the attached figures

[0035] 1: Inkjet printer; 2: Control unit; 3: Header unit; 4: Drive signal generation unit; 6, 6A, 6B, 6C: Inspection 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 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: Inverters; N: Nozzle; SW11, SW12, SW21, SW22, SWc1, SWc2: Switches; TM: Check module. Detailed Implementation

[0036] Hereinafter, 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 made different from the actual dimensions. Furthermore, the embodiments described below are preferred examples of the present invention, and therefore various technically preferred limitations have been added. However, unless otherwise specified in the following description, the scope of the present invention is not limited to these embodiments.

[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 a liquid ejection device. It should be noted that in this embodiment, "ink" refers to an example of "liquid". First, refer to... Figure 1 The configuration of the inkjet printer 1 according to this embodiment will be described.

[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 the first embodiment of the present invention.

[0041] For example, a host computer or digital camera supplies inkjet printer 1 with print data IMG representing an image that inkjet printer 1 should form. Inkjet printer 1 performs a printing process that forms the image shown in the print data IMG supplied from the host computer onto a medium. In this embodiment, the medium is envisioned to be the medium described below. Figure 2 The recording paper P shown is 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 of the head unit 3. It should be noted that 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 printing data IMG and various information such as the control program PG of the inkjet printer 1; and a check module TM, including a check unit 6 that determines the state of the ejector section D.

[0044] In this embodiment, it is envisioned 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 to each of the multiple head units 3. Alternatively, the inkjet printer 1 may have one head unit 3 and one inspection unit 6 corresponding to that head unit 3. In this embodiment, it is envisioned that the inkjet printer 1 has four head units 3 and four inspection units 6 corresponding to each of the four head units 3. However, for ease of explanation, the following description will focus on one of the four head units 3 and one of the four inspection units 6, which is provided in correspondence with one of the head units 3.

[0045] The control unit 2 is configured to include one or more CPUs (Central Processing Units). It should be noted that the control unit 2 may also replace the CPU, or include programmable logic devices such as FPGAs (Field-Programmable Gate Arrays) in addition to the CPU. Furthermore, the control unit 2 functions as the 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 shielding signal MSK to control the operation of various parts 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 shielding signal MSK will be described below. Figure 7 and Figure 8 The explanation is provided below.

[0047] In the case of printing, for example, the drive control unit 22 controls the head unit 3 and the transport unit 7 to print the image shown in the printing data IMG onto the recording paper P. Specifically, in the case of printing, 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, in the case of printing, the drive control unit 22 generates a waveform specification signal dCOM or similar signal to control the drive signal generation unit 4. Furthermore, in the case of printing, the drive control unit 22 generates a signal to control the transport unit 7. Thus, in the printing process, while controlling the transport unit 7 to change the relative position of the recording paper P with respect to the head unit 3, the drive control unit 22 adjusts whether ink is ejected from the ejector 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 on 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 defined 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. It should be noted that in this embodiment, it is envisioned that the head units 3 correspond to each other with the drive signals COM. For example, the inkjet printer 1 may also 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 the following: 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 Read-Only Memory). It should be noted that 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. It should be noted that 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 will sometimes be referred to as ejector section D[j]. Here, the variable j is a natural number satisfying "1≤j≤J". Furthermore, in the following cases where the constituent elements or signals of the inkjet printer 1 correspond to the ejector section D[j] among the J ejector sections D, the reference numerals used to represent that constituent element or signal will sometimes be 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. It should be noted that, as will be described below... 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, an analog signal representing the change in 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 after the piezoelectric element PZ[j] is driven by the independent drive signal Vin[j], along with the vibration remaining in the ejector section D[j]. In this case, the waveform of the detection signal Vout[j] represents, for example, the waveform of the residual vibration, which is the vibration remaining in 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. It should be noted that the piezoelectric element PZ, the upper electrode Zu[j], and the vibrating plate 321 will be discussed in detail later. Figure 3 This will be described in detail below.

[0054] The detection circuit 33 generates a residual vibration signal VD[j] corresponding to the detection signal Vout[j] as a signal for determining 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 in the inspection unit 6 by amplifying the amplitude of the detection signal Vout[j] or removing the noise components included in the detection signal Vout[j]. Thus, the residual vibration signal VD[j] is generated. For example, the detection circuit 33 may also 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 conversion 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 an analog signal representing 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] Inspection unit 6 determines the state of the ejector section D[j] based, for example, on the residual vibration signal VD[j]. It should be noted that, in Figure 1 The following section briefly outlines the overview of inspection unit 6, and will be described in detail below. Figure 7 The details of the inspection unit 6 will be explained below. Furthermore, in this embodiment, it is envisioned that the inspection unit 6 has a first inspection mode and a second inspection mode as inspection modes for determining the state of the ejection section D. For example, the first inspection mode is an 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, by selecting the first inspection mode as the inspection mode, the inspection time can be shortened. It should be noted that in this embodiment, by selecting the second inspection mode as the inspection mode, various state abnormalities, including the thickening state of the ink within the ejection section D, can be determined.

[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 ejector section D based on the state inspection signal. For example, the determination unit 64 determines the state of the ejector section D based on the state inspection signal generated by the signal generation unit 60, and generates state information Cinf including information indicating the result of the determination. Examples of the state of the ejector section D include, for instance, the thickening state of the ink within the ejector 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 thickening state of the ink within the ejector section D[j]. In this case, it is possible to suppress the printing process from being performed in an abnormal state caused by the thickening of the ink within the ejector section D[j]. Hereinafter, the process of determining the state of the ejector section D[j] will be referred to as the ejector state determination process. Furthermore, the ejector section D whose state is determined will be referred to as the ejector 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 ejection section D subject to determination.

[0059] Furthermore, during the ejection state determination process, the drive control unit 22 controls the head unit 3 by generating a printing signal SI, so that a detection signal Vout[j] corresponding to the ejection section D[j] driven by the ejection section D being determined is supplied 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] being determined. Then, the inspection unit 6 determines the state of the ejection section D[j] being determined 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] It should be noted that 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. These procedures include, for example, 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 similar device. Regarding the nozzle N, [further details will be provided later]. Figure 3 This will be described in detail below.

[0062] For example, through a rinsing process, the continuously thickening ink is discharged from the ejection section D; this thickening refers to an increase in viscosity. As a result, the viscosity of the ink in the nozzle N at the start of the printing process can be kept below a specified viscosity. In this case, since the thickened ink is discharged from the ejection section D, it is possible to suppress the degradation of the image quality printed through the printing process.

[0063] The maintenance unit 8 includes an ink discharge receiving unit 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 pump for suctioning ink, air bubbles, etc., from the ejector section D. It should be noted that the ink discharge receiving unit 80 will be described in detail below. Figure 2 This will be described below. Additionally, illustrations of the wiper and pump are omitted. Next, refer to... Figure 2 A brief description of the internal structure of inkjet printer 1 will be provided.

[0064] Figure 2 This is a perspective view showing an example of the simplified 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 ejects ink from the ejection section D[j] while feeding the recording paper P along the sub-scanning direction, and while reciprocating the head module HM in the main scanning direction that intersects the sub-scanning direction, thereby forming dots on the recording paper P corresponding to the printing data IMG.

[0066] For ease of explanation, a three-axis orthogonal coordinate system with mutually orthogonal X, Y, and Z axes will be appropriately introduced below. For example, in this embodiment, the Y1 direction along the Y-axis is designated as the secondary scanning direction, and the X1 and X2 directions along the X-axis are designated as the primary scanning directions. It should be noted that the X2 direction is the opposite direction to the X1 direction. Furthermore, in this embodiment, as... Figure 2As illustrated, the Z1 direction along the Z-axis is defined as the ink ejection direction 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. It should be noted that in this embodiment, as described above, the X-axis, Y-axis, and Z-axis are assumed to be orthogonal to each other, but the present invention is not limited to this aspect. 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 housing 100 and a carriage 110 that can reciprocate in the X-axis direction within the housing 100. A head module HM including four head units 3 is mounted on the carriage 110.

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

[0069] Additionally, as in Figure 1 As described above, the inkjet printer 1 according to this embodiment includes a transport unit 7. The transport unit 7 includes a carriage transport mechanism 71 for reciprocating the carriage 110 in the X-axis direction, and a carriage guide shaft 76 for supporting the carriage 110 so that it reciprocates freely in the X-axis direction. The transport unit 7 also includes a media transport mechanism 73 for transporting 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 transport 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, and the media transport mechanism 73 transports the recording paper P on the impression plate 75 in the Y1 direction. Therefore, in the printing process, by performing the above-described actions by the carriage transport mechanism 71 and the media transport mechanism 73, the transport unit 7 changes the relative position of the recording paper P relative to the head module HM, enabling ink to fall on the entire recording paper P.

[0070] Next, refer to Figure 3 A brief description of the structure of the recording head 32 is provided.

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

[0072] The ejection section D[j] has a cavity CV filled with ink, a nozzle N communicating with the cavity CV, a piezoelectric element PZ[j] that causes pressure fluctuations 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] ejects the ink within the cavity CV from the nozzle N by driving the piezoelectric element PZ[j] with the independent drive signal Vin[j].

[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 element Zb[j] disposed between the upper electrode Zu[j] and the lower electrode Zd[j]. The piezoelectric element 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 is supplied with an independent drive signal Vin[j]. The lower electrode Zd[j] is electrically connected to the wiring Ld, which is supplied with a base potential signal VBS. Furthermore, by supplying the upper electrode Zu[j] with an 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 the Z1 or Z2 direction depending on 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 lower electrode Zd[j] is engaged with the vibrating plate 321. For this purpose, the piezoelectric element PZ[j] is driven to vibrate by an independent drive signal Vin[j], thereby causing the vibrating plate 321 to vibrate as well. Then, due to the vibration of the vibrating plate 321, the volume of the cavity CV and the pressure within the cavity CV change, and the ink filled in the cavity CV is ejected from the nozzle N.

[0076] In this embodiment, as an example, we envision a situation where the piezoelectric element PZ shifts in the Z1 direction as the potential of the independent drive signal Vin[j] supplied to the ejector section D[j] changes from a low potential to a high potential. That is, in this embodiment, we envision a situation where, when the potential of the independent drive signal Vin[j] supplied to the ejector section D[j] is high, the volume of the cavity CV provided by the ejector section D[j] is smaller compared to the case of a low potential.

[0077] Then, while referring to Figure 4 The ink ejection action in the ejection section D is explained.

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

[0079] For example, in Phase-1, the drive control unit 22 changes the potential of the drive signal COM supplied to the piezoelectric element PZ of the ejector section D, causing the piezoelectric element PZ to deform in the Z2 direction. As a result, the vibrating plate 321 of the ejector section D flexes in the Z2 direction. Consequently, as... Figure 4 As shown in stage-2, compared to stage-1, the volume of the cavity CV of the ejector section D increases. Next, for example, in stage-2, the drive control unit 22 changes the potential of the drive signal COM, causing the piezoelectric element PZ to deform in the Z1 direction. As a result, the vibrating plate 321 of the ejector section D flexes in the Z1 direction. Consequently, as... Figure 4 As shown in stage-3, the volume of the cavity CV shrinks rapidly, 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 of the ejection section D are displaced in the Z-axis direction by the drive signal COM driving the piezoelectric element PZ of the ejection section D. As a result, 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 An example of the configuration of nozzle N will be explained.

[0082] Figure 5 This is a top view showing an example of the configuration of nozzle N in head unit 3. It should be noted that... 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 when 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 array NL. Here, a nozzle array NL refers to a plurality of nozzles N arranged in a row in a predetermined direction. In this embodiment, as an example, it is envisioned that each nozzle array NL is composed of J nozzles N arranged in a row in the Y-axis direction.

[0084] Next, refer to Figure 6 The general outline of head unit 3 is described below.

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

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

[0087] The switching circuit 31 has J switches SWA[1] to SWA[J] corresponding one-to-one with the J ejector parts D[1] to D[J], J switches SWs[1] to SWs[J] corresponding one-to-one with the J ejector parts D[1] to D[J], and a connection status 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 envisioned that each of the J switches SWA and J switches SWs comprises a transmission gate consisting of a P-channel transistor and an N-channel transistor connected in parallel. However, each of the J switches SWA and J switches SWs may also be composed of either a P-channel transistor or an N-channel transistor.

[0090] The switch SWA[j] switches the conduction and deconduction of wiring La and the upper electrode Zu[j] of the piezoelectric element PZ[j] provided in the ejector section D[j] based on the connection state specification signal Qa[j]. That is, the switch SWA[j] switches the conduction and deconduction of 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 it is low. When the switch SWA[j] is turned on, the drive signal COM supplied to wiring La is supplied to the upper electrode Zu[j] of the ejector section D[j] via wiring Li[j] as an independent drive signal Vin[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 it is low.

[0092] For example, when detecting residual vibration of the ejector section D[j], the connection state specification signal Qs[j] becomes high. Thus, residual vibration of the ejector section D, the object to be judged, is detected. By turning on the switch SWs[j], 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], is supplied 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] It should be noted that when the switch SWs[j] is turned off, the supply of the residual vibration signal VD[j] to the signal generation unit 60 ends. For example, when the switch SWs[j] is turned off, wiring Ls and wiring Li[j] become non-conductive, thus blocking the signal path from the ejector D to the signal generation unit 60 for the residual vibration signal VD. That is, the signal generation unit 60 is not electrically connected to 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 from the ejector D to the signal generation unit 60 for the residual vibration signal VD being blocked. It should be noted that the connection state specifying signal Qs is an example of a "blocking signal". In addition, in the signal path from the ejector D[j] to the signal generation unit 60 for the residual vibration signal VD, 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 The inspection unit 6 will be described.

[0095] Figure 7 This is a block diagram illustrating an example of the configuration of inspection unit 6. (As shown in...) Figure 1 As described above, the inspection unit 6 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 including comparison circuits 620, 621 and 622, and an adjustment unit 63 including 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] The comparator circuit 620 compares, for example, the potential of the residual vibration signal VD with a threshold potential VthC and generates a comparison signal CPc representing the comparison result. Specifically, the comparator circuit 620 generates a comparison signal CPc that is high when the potential of the residual vibration signal VD is above the threshold potential VthC and low when the potential of the residual vibration signal VD is below the threshold potential VthC.

[0099] In addition, a comparison circuit 621 compares, for example, the potential of the residual vibration signal VD with a threshold potential Vth1 and generates a comparison signal CP1 indicating the comparison result. Specifically, the comparison circuit 621 generates a comparison signal CP1 that goes high when the potential of the residual vibration signal VD is above the threshold potential Vth1 and goes low when the potential of the residual vibration signal VD is less than the threshold potential Vth1.

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

[0101] It should be noted that in the present embodiment, the threshold potential VthC is the potential of the amplitude center level of the residual vibration signal VD, and the threshold potentials VthC, Vth1, and Vth2 satisfy "VthC < Vth2 < Vth1". In addition, in the present embodiment, the threshold potentials VthC, Vth1, and Vth2 satisfy "|Vth2 - VthC| < |Vth1 - VthC|". The threshold potential VthC is an example of the "first potential", and the threshold potentials Vth1 and Vth2 are examples of the "second potential".

[0102] The comparison signals CPc, CP1, and CP2 are respectively supplied to adjustment circuits 630, 631, and 632 included in the adjustment unit 63. Hereinafter, the comparison signals CPc, CP1, and CP2 may be collectively referred to as the comparison signal CP. The comparison signal CP is an example of the "inspection signal". Furthermore, the comparison signal CPc in the comparison signal CP corresponds to the "reference signal".

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

[0104] It should be noted that, as will be described below Figure 9 As shown, the pulse detection period signal Pcut is a signal that defines the reset timing tep for resetting the comparison signal CCP. For example, during the period when the comparison signal CP is valid as a signal for generating the comparison signal CCP, the pulse detection period signal Pcut is maintained at a high level. The pulse detection period signal Pcut is an example of the "reset signal".

[0105] Furthermore, the shielding signal MSK is a signal that is invalid during the shielding period when the comparison signal CP is defined as the signal used to generate the comparison signal CCP in the second inspection mode. Therefore, the residual vibration signal VD during the shielding period is not used to determine the state of the ejection section D. In this embodiment, it is assumed that the shielding signal MSK remains at a high level during the shielding period. For example, in the second inspection mode, from the time the switch SWs[j] is turned on until a predetermined time has elapsed, the shielding signal MSK remains at a high level and then becomes low after the predetermined time has elapsed. It should be noted that in the first inspection mode, the shielding signal MSK remains at a low level.

[0106] For example, the adjustment circuit 630 of the adjustment unit 63 generates a comparison signal CCPc, which is a logical AND of the inverted signal of the shielding 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 CPC. It should be noted that the inverted signal of the shielding signal MSK is, for example, a signal that becomes high when the shielding signal MSK is low and low when the shielding signal MSK is high.

[0107] Furthermore, the adjustment circuit 631 included in the adjustment unit 63 generates, for example, a comparison signal CCP1, which is a logical AND of the inverted signal representing the shielding signal MSK, the pulse detection period signal Pcut, and the comparison signal CP1. Therefore, 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 a logical AND of the inverted signal representing the shielding signal MSK, the pulse detection period signal Pcut, and the comparison signal CP2. Therefore, 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. It should be noted that, for example, when the blocking timing is earlier than the reset timing tep, the comparison signal CCPc is equivalent to a signal whose potential at the blocking timing of comparison signal CPc is maintained until the reset timing tep. Similarly, the comparison signal CCP1 is equivalent to a signal whose potential at the blocking timing of comparison signal CP1 is maintained until the reset timing tep, and the comparison signal CCP2 is equivalent to a signal whose potential at the blocking timing of comparison signal CP2 is maintained until the reset timing tep.

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

[0111] The determination unit 64 includes a determination unit 67 including 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. Then, for example, the determination circuit 670 determines the duration TCc of the period WCc during which the comparison signal CCPc is high, and outputs the time information NTCc representing this duration TCc to the amplitude calculation circuit 68. It should be noted that in this embodiment, as will be described below... Figure 9 As shown, the period WCc of the duration TCc is determined to be a period later than the time t0 when the residual vibration signal VD is first supplied to the signal generation unit 60, and 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 representing this duration TC1 to the amplitude calculation circuit 68. Here, as Figure 9 As shown, the duration TC1 is determined to be a period WC1 that is later than time t0, which is the period during which the comparison signal CCP1 is initially held at a high level.

[0114] Additionally, the determining circuit 672 determines the duration TC2 of the period when the comparison signal CCP2 is high (WC2), and outputs the time information NTC2 representing this duration TC2 to the amplitude calculation circuit 68. Here, as... Figure 9As shown, the duration TC2 is determined to be a period WC2 that follows time t0, and is the period during which the comparison signal CCP2 is initially held high. Hereinafter, durations TCc, TC1, and TC2 will sometimes be collectively referred to as duration TC, and time information NTCc, NTC1, and NTC2 will be collectively referred to as time information NTC. Time information NTC is an example of "checking signal information".

[0115] Amplitude calculation circuit 68, for example, calculates and Figure 9 The amplitude Vamp is the equivalent of the amplitude VPK of the residual vibration signal VD shown. It should be noted that the amplitude Vamp equivalent to the amplitude VPK of the residual vibration signal VD includes the same amplitude as the amplitude VPK, the amplitude after amplifying the amplitude VPK, and the amplitude after attenuating the amplitude VPK. Hereinafter, the amplitude Vamp equivalent 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 has a first calculation mode and a second calculation mode as calculation modes for calculating the amplitude Vamp of the residual vibration signal VD. For example, in the first calculation mode, the amplitude calculation circuit 68 calculates the amplitude Vamp based on the durations 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 durations 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. It should be noted that equations (1) and (2) below are used to calculate the amplitude Vamp by approximating the waveform of the residual vibration signal VD as a sine wave.

[0118] [Mathematical Expression 1]

[0119]

[0120] For example, the calculation mode (either the first or the second calculation mode) for calculating amplitude Vamp can be predefined for each nozzle N. Alternatively, the amplitude calculation circuit 68 can determine which calculation mode (first or second) to use to calculate amplitude Vamp based on the duration TC1. Specifically, for example, the amplitude calculation circuit 68 can calculate amplitude Vamp using the first calculation mode when the duration TC1 is longer than the first reference time, and calculate amplitude Vamp using the second calculation mode when the duration TC1 is shorter than the second reference time (below the first reference time). It should be noted that when the duration TC1 is greater than the second reference time and less than the first reference time, amplitude Vamp can also be calculated using the previous calculation mode. The initial calculation mode is, for example, the first calculation mode. In the above example, the switching of calculation modes has a hysteresis characteristic, but the switching of calculation modes may also not have a hysteresis characteristic.

[0121] The amplitude calculation circuit 68 outputs the amplitude information NVamp, representing the amplitude Vamp, as waveform information representing the characteristics of the residual vibration signal VD to the determination circuit 69. Here, the characteristics of the residual vibration signal VD's waveform are, for example, information related to the shape of the residual vibration signal VD's waveform, such as its amplitude VPK and period. In this embodiment, as described above, it is envisioned that the amplitude information NVamp, representing 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 including information indicating the result of the determination. It should be noted that, for example, when the inspection mode is the second inspection mode, the determination circuit 69 may also acquire, in addition to the amplitude information NVamp, the duration TCc of the period WCc during which the comparison signal CCPc is high, as waveform information. In this case, the determination circuit 69 can also determine the ejection state of the ink in the ejection section D based on the amplitude Vamp and duration TCc of the residual vibration signal VD. It should be noted that, 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 for determining the state of the ejection section D based on the amplitude VPK of the residual vibration signal VD can be used.

[0123] Next, refer to Figure 8 The operation of inkjet printer 1 will be explained.

[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 to perform 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 determination object in each unit period TU and detect the detection signal Vout[j] from the ejection section D of the determination object.

[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 independently specified signals Sd[1] to Sd[J] corresponding one-to-one with the J ejector sections D[1] to D[J]. When the inkjet printer 1 performs printing processing or ejection state determination processing, the independently specified signal Sd[j] specifies the driving mode of the ejector section D[j] for each unit period TU. For example, before each unit period TU, the control unit 2 supplies the printing signal SI, including the independently specified signals Sd[1] to Sd[J], to the connection state specifying circuit 310 synchronously with the clock signal CL. Then, the connection state specifying circuit 310 generates connection state specifying signals Qa[j] and Qs[j] based on the independently specified signals Sd[j] during that unit period TU.

[0127] For example, during a unit period TU of printing processing, the ejector section D[j] is designated by the 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 independent designation signal Sd[j] specifies whether to drive the ejector section D[j] as the determination target. It should be noted that in... Figure 8 The diagram shows the connection state designation signals Qa[j] and Qs[j], etc., when the TU designates the ejection section D[j] as the ejection section D to be determined by the independent designation signal Sd[j] during a unit period of the ejection state determination process. Figure 8 The following section describes the operation of inkjet printer 1 when performing ejection status determination processing. Additionally, in... Figure 8 In the case of the first inspection mode, the shielding signal MSK remains low during the 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, control unit 2 defines the effective period TPval of comparison signal CP by controlling pulse detection period signal Pcut. For example, drive control unit 22 of control unit 2 sets pulse detection period signal Pcut to high level when pulse PlsT1 ends, and sets pulse detection period signal Pcut to low level when pulse PlsT2 begins. In this case, the period during which the logical AND result of the inverted signal of shielding signal MSK and pulse detection period signal Pcut is high corresponds to the effective period TPval. In the first check mode, such as Figure 8 As shown, during the unit period TU, since the shielding signal MSK remains at a low level, 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 the wiring La during the control period (TSS1). The pulse PA used for ejection state determination processing can be any pulse that causes the vibrator 321 to vibrate; it can be a pulse that prevents ink from being ejected from the nozzle N, or a pulse that causes ink to be ejected from the nozzle N. In this embodiment, it is assumed that the pulse PA is the one that prevents ink from being ejected from the nozzle N. It should be noted that during the printing process, within a unit period TU, a pulse that causes ink to be ejected from the nozzle N is supplied to the wiring La instead of the pulse PA.

[0131] The pulse PA is the waveform of the drive signal COM returning to potential V0 from potential V0 via a potential VLa that is lower than potential V0. Potential V0 is the potential at the beginning and end of the pulse PA, and is the reference potential of 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 potential VLa at the end of waveform element Pa1, 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 of the driving signal COM changes in order to drive the piezoelectric element PZ to expand the volume of the cavity CV. Therefore, in waveform element Pa1, the potential of the driving signal COM changes, causing the volume of the cavity CV to expand. In the case of volume expansion of the cavity CV, as... Figure 4 As shown in stage-2, the surface of the ink inside nozzle N is pulled in the Z2 direction, which is the opposite direction to the ejection direction. Hereinafter, the situation where the surface of the ink inside nozzle N is pulled in the opposite direction to the ejection direction is sometimes referred to as pulling.

[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, in order to drive the piezoelectric element PZ to maintain the volume of the cavity CV that expands through waveform element Pa1, the potential of the drive signal COM is maintained.

[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, the potential of the drive signal COM changes. Therefore, in waveform element Pa3, the potential of the drive signal COM changes, causing the volume of the cavity CV to shrink. When the volume of the cavity CV shrinks, the surface of the ink in the nozzle N is pushed in the Z1 direction, which is the ejection direction. In this embodiment, the surface of the ink in the nozzle N is pushed in the Z1 direction by waveform element Pa3 to the extent that the ink is not ejected from the nozzle N. Hereinafter, the case of pushing the surface of the ink in the nozzle N out in the ejection direction is sometimes referred to as pushing.

[0136] Thus, the pulse PA is a 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 a 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] It should be noted that, preferably during the switching control period TSS1 and control period TSS2, the states of switches SWA[j] and SWs[j] are switched between on and off by both being on. That is, preferably, 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. Furthermore, preferably, 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, during the switching control period TSS1 and control period TSS2, the state where both switches SWA[j] and SWs[j] are off will not occur, thus suppressing [the occurrence of such a state]. Figure 6 The potential of the wiring Ls shown changes due to switching noise, etc.

[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 based on the start of pulse PlsT2. It should be noted that the drive control unit 22 of the control unit 2 only needs to satisfy the above transition timing; it may also set the pulse detection period signal Pcut to high based on the start of pulse PlsT1 and to low based on the start of the next pulse PlsL.

[0140] It should be noted that 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. Therefore, the timing of the signal Pcut transitioning from high to low during pulse detection will sometimes be referred to as the reset timing tep.

[0141] During control, 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 TSS1. Specifically, the piezoelectric element PZ[j] of the ejection section D[j] of the object being judged is displaced according to the pulse PA of the drive signal COM during control. As a result, vibration is generated in the ejection section D[j] of the object being judged. The vibration generated by TSS1 during control also remains in TSS2 during control. Moreover, during 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 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, during the control period TSS2, the potential of the upper electrode Zu is detected as a detection signal Vout. Thus, during the control period TSS2, the change in the potential of the upper electrode Zu is detected as a detection signal Vout. Consequently, 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] During the control period TSS2, the detection signal Vout input to the detection circuit 33 is supplied to the signal generation unit 60 as a residual vibration signal VD. 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 described. It should be noted that during the printing process, the unit period TU may not be divided into control period TSS1 and control period TSS2. In this case, the period specification signal Tsig may be maintained low and the pulse detection period signal Pcut may be maintained low during the unit period TU.

[0144] During the unit period TU, the connection status designation signal Qs[j] remains at a low level, regardless of whether the ejector part D[j] is designated as the forming point of the ejector part D. In addition, the connection status designation signal Qa[j] is set to a high level or a low level depending on whether the ejector part D[j] is designated as the forming point of the ejector part D.

[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. It should be noted that during the unit period TU, the connection state designation signal Qa corresponding to the ejector section D that does not form a point is set to a low level.

[0146] By setting the connection state specification signal Qa[j] to a high level, a drive signal COM, including a pulse that causes ink to be ejected from the nozzle N, is supplied from the drive signal generation unit 4 to the ejection section D of the forming point. For example, during a unit period TU, a pulse that causes ink to be ejected from the nozzle N is supplied to the wiring La. The pulse that causes ink to be ejected from the nozzle N can also be a pull-push waveform, similar to the pulse PA. In this case, the pulse that causes ink to be ejected from the nozzle N is specified 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 the pulse PA. It should be noted that the pulse that causes ink to be ejected from the nozzle N is not limited to a pull-push waveform. For example, the pulse that causes ink to be ejected from the 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 so that when an independent drive signal Vin[j] with the pulse is supplied to ejection section D[j], a predetermined amount of ink is ejected from ejection section D[j]. In this embodiment, it is envisioned 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 compared to the case of a low potential. Therefore, when ejection section D[j] is driven by independent drive signal Vin[j] with the pulse that causes ink to be ejected, the ink in ejection section D[j] is ejected from nozzle N by the waveform element of the independent drive signal Vin[j] changing from a low potential to a high potential.

[0148] For example, the waveform elements of the pulse that causes ink to be ejected from nozzle N are defined based on the ejection characteristics of the ink in ejection section D. The ejection characteristics of the ink include, for example, the amount of ink ejected as droplets and the ejection velocity of the ejected droplets. It should be noted that the ejection velocity of the droplets varies, for example, depending on the viscosity of the ink. For example, the ejection velocity of droplets thickened above a specified viscosity is lower than that of droplets with a specified viscosity. In this embodiment, the thickening state of the ink in ejection section D can be determined based on the amplitude Vamp, represented by the amplitude information NVamp.

[0149] In this embodiment, since the pulse PA is assumed to be a pulse that prevents ink from being ejected from the nozzle N, 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, when printing is performed one pass at a time while moving the head unit 3 along the X-axis, the ejection state determination process can be performed between passes. Furthermore, the ejection state determination process can be performed between printing jobs based on one printing data IMG and printing jobs based on other printing data IMGs. Alternatively, the ejection state determination process can be performed during maintenance processing.

[0150] It should be noted that the operation of inkjet printer 1 is not limited to Figure 8 The example shown. For example, the pulse PA can also be a pulse that causes ink to be ejected from the nozzle N. In this case, the drive signal COM, including the pulse PA, can also be used for both printing processing and ejection state determination processing. However, when the pulse PA used for ejection state determination processing is a pulse that causes ink to be ejected from the nozzle N, it is preferable to perform the ejection state determination processing when the head unit 3 is located on the ink discharge receiving section 80.

[0151] Alternatively, for example, when performing ejection state determination processing, the control unit 2 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 when pulse PlsT1 begins or ends, and set the pulse detection period signal Pcut to a low level when the next pulse PlsL begins, in a manner that satisfies the aforementioned timing transition.

[0152] Additionally, for example, in Figure 8 The example shown illustrates a single drive signal COM, but the invention is not limited to this aspect. For example, 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, the pulse PA that prevents ink ejection can also be used to prevent ink thickening during the printing process. Alternatively, the drive signal COM that allows ink to be ejected from nozzle N can also have 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. It should be noted that... Figure 9 In the diagram, solid lines represent the comparison signal CCP when the inspection mode is the first inspection mode, and dashed lines represent the comparison signal CCP when the inspection mode is the second inspection mode. Figure 9 In this section, the comparison signal CCP and other parameters are explained in the case where the inspection mode is the first inspection mode.

[0155] Figure 9 The time t0 represents the timing at which the residual vibration signal VD begins to be supplied to the signal generation unit 60. The timing for starting to supply the residual vibration signal VD to the signal generation unit 60 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 In order to make the explanation easy to understand, regardless of the inspection mode, the comparison signal CCP and others are explained by keeping the connection state specification signal Qs[j] high from time t0 to time t45.

[0156] exist Figure 9 In this scenario, it is assumed 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. The first peak value PK1 of the residual vibration signal VD is the peak value when 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 value when 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 value when the potential of the residual vibration signal VD reaches a maximum. Hereinafter, the peak values ​​PK1, PK2, and PK3 of the residual vibration signal VD, as well as all other peak values ​​of the residual vibration signal VD, are sometimes collectively referred to as peak values ​​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. Moreover, 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, the comparison signals CPC, CP1, and CP2 are explained by maintaining the connection state specification signal Qs[j] at a high level from time t0 to time t45.

[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 transitions the comparator signal CPc from low to high at time t10. Hereinafter, the timing of the transition of the comparator signal CPc from low to high 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 transitions the comparator signal CP2 from low to high at time t12. Hereinafter, the timing of the transition of the comparator signal CP2 from low to high is sometimes referred to as timing ts2. For example, in... Figure 9 In this context, time t12 corresponds to time ts2. Additionally, below, 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 transitions the comparator signal CP1 from low to high at time t14. Hereinafter, the timing of the transition of the comparator signal CP1 from low to high 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] Then, 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 changes the comparator signal CP1 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 changes the comparator signal CP2 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 comparison signal CPc indicating whether the potential of the residual vibration signal VD is above the threshold potential VthC, the comparator circuit 621 generates a comparison 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 comparison 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 at a reset timing tep specified by the pulse detection signal Pcut. It should be noted that, in the first check mode, preferably, the reset timing tep for the pulse detection signal Pcut to transition from high to low is 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 at timer tsc when it transitions from low to high, and the reset timer tep transitions from high to low during pulse detection when the signal Pcut transitions from high to low. Therefore, the period WCc during which the comparison signal CCPc is high is the period from timer tsc to reset timer tep, and the duration TCc of WCc corresponds to the elapsed time from timer tsc to reset timer tep.

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

[0171] Additionally, for example, the comparison signal CCP1 transitions from low to high at timing ts1, and then from high to low at 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 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 residual vibration signal VD during the first period TPP1 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. It should be noted that, preferably, the first period TPP1 begins before a first time elapses after the residual vibration signal VD is 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 standby time from the time the residual vibration signal VD is input to the signal generation unit 60 until the generation of the comparison signal CCP begins from becoming longer. It should be noted that... Figure 9 The comparison signals CCPc, CCP1, and CCP2 shown by the solid lines are examples of "status check signals" and "first check mode signals".

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

[0174] VE=VPK·sin(ωt)……(3)

[0175] In addition, since the duration 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, the duration TCc is used, and the angular velocity ω is expressed by equation (4).

[0176] ω=π / (2·TCc)……(4)

[0177] In addition, the formula “TCc-TC1”, which is the result of subtracting the duration TC1 from the duration TCc, represents the elapsed time from time t10 to time t14, and the formula “TCc-TC2”, which is the result of subtracting the duration TC2 from the duration TCc, represents the elapsed time from time t10 to time t12.

[0178] Therefore, using durations TCc and TC1, equation (5) represents the potential difference VE1 between the residual vibration signal VD at time t14 and the threshold potential VthC. Additionally, using durations TCc and TC2, equation (6) represents the potential difference VE2 between the residual vibration signal VD at time t12 and the threshold potential VthC.

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

[0180] VE2=VPK·sin(π·(TCc-TC2) / (2·TCc))……(6) In addition, the amplitude VPK is expressed by equation (7) by transforming equation (5). Or, the amplitude VPK is expressed by equation (8) by transforming equation (6).

[0181] VPK=VE1 / (sin((π / 2)·(1-TC1 / TCc)))……(7)

[0182] VPK=VE2 / (sin((π / 2)·(1-TC2 / TCc)))……(8)

[0183] Since the potential at time t14 of the residual vibration signal VD is the threshold potential Vth1, the potential difference VE1 is the value obtained by subtracting the threshold potential VthC from the threshold potential Vth1. Therefore, 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), the value is derived. Figure 7 Equation (1) is explained in the text. Furthermore, since the potential at time t12 of the residual vibration signal VD is the threshold potential Vth2, the potential difference VE2 becomes the value obtained by subtracting the threshold potential VthC from the threshold potential Vth2. Therefore, 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), the result is derived. Figure 7 Equation (2) is explained in the text.

[0184] Details will be available in Figure 10As will be explained later, the amplitude Vamp calculated according to equation (1) can be adjusted by adjusting at least one of the potential difference between the threshold potential VthC and the threshold potential Vth1, and the time ratio, which is the ratio of duration TC1 to duration TCc. By adjusting the amplitude Vamp calculated according to equation (1), the difference between the amplitude Vamp calculated according to equation (1) in the normal state of the ejector section D and the amplitude Vamp calculated according to equation (1) in the abnormal state of the ejector section D can be adjusted. Therefore, by adjusting the amplitude Vamp calculated according to equation (1), the sensitivity for determining the state of the ejector section D can be adjusted. Similarly, by adjusting the amplitude Vamp calculated according to equation (2), the sensitivity for determining the state of the ejector section D can be adjusted. In this embodiment, the sensitivity for determining the state of the ejector section D can be adjusted by adjusting the amplitude Vamp calculated according to equation (1), and the sensitivity for determining the state of the ejector section D can also be adjusted by adjusting the amplitude Vamp calculated according to equation (2).

[0185] Next, a brief explanation will be given regarding the comparison signal CCP, etc., when the inspection mode is the second inspection mode. In the second inspection mode, the amplitude of the peak value PK3 of the residual vibration signal VD is used instead of the amplitude of the peak value PK1 of the residual vibration signal VD for determining the state of the ejection section D. Therefore, for example, the comparison signal CP from time t0 to time t25 is not used for determining the state of the ejection section D. For this reason, in the second inspection mode, for example, as... Figure 9 As shown by the dashed line, the shielding signal MSK remains high from time t0 to time t25, and then transitions from high to low at time t25. Then, for example, the shielding signal MSK remains low from time t25 to time t45. During the period when the shielding signal MSK is high, i.e., from time t0 to time t25, the comparison signal CCP remains low regardless of the level of the comparison signal CP.

[0186] Additionally, in the second inspection mode, for example, such as Figure 9 As shown by the dashed line, during the pulse detection period, the signal Pcut remains high until time t45, at which point it transitions from high to low. Therefore, in the second check mode, time t45 corresponds to the reset timing tep.

[0187] 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.

[0188] 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.

[0189] 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 changes the comparator signal CP2 from low to high at time t32.

[0190] 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 changes the comparator signal CP1 from low level to high level at time t34.

[0191] 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.

[0192] 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 changes the comparator signal CP1 from high level to low level at time t36.

[0193] 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 changes the comparator signal CP2 from high level to low level at time t38.

[0194] 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 changes the comparator signal CPc from high level to low level at time t40.

[0195] In the second check mode, the time t45 corresponding to the reset timing tep is a time that is later than time t40. Therefore, for example, as... Figure 9 As shown by the dashed line, the comparison signal CCPc generated by the logical AND of the inverted signal MSK, the pulse detection period signal Pcut, and the comparison signal CPC becomes the same signal as the comparison signal CPCc. Additionally, as... Figure 9 As shown by the dashed line, the comparison signal CCP1 generated by the logical AND of the inverted signal of the masked signal MSK, the pulse detection period signal Pcut, and the comparison signal CP1 becomes the same signal as the comparison signal CP1. Furthermore, as... Figure 9 As shown by the dashed line, the comparison signal CCP2 generated by the logical AND of the inverted signal of the shielded signal MSK, the pulse detection period signal Pcut, and the comparison signal CP2 becomes the same signal as the comparison signal CP2.

[0196] 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). It should be noted that in the second inspection mode, the waveform of the residual vibration signal VD is also approximated as a sine wave, thereby... Figure 7 The amplitude Vamp of the residual vibration signal VD is calculated using equation (1) or equation (2) as described in the text.

[0197] Thus, in the second inspection mode, comparison signals CCPc, CCP1, and CCP2 are generated corresponding to the second portion of the signal TPP2 during the second period from time t30 to time t40 in the residual vibration signal VD. 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, various abnormal states, including the thickening 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 comparison signals CCPc, CCP1, and CCP2 shown by the dashed lines are examples of "status check signals" and "second check mode signals".

[0198] Here, the second period TPP2 is a period that follows the first period TPP1, but is also longer than the first period TPP1. Therefore, in the second inspection mode, even during switching... Figure 8Even when noise is superimposed on the residual vibration signal VD during the control periods TSS1 and TSS2 shown, the influence of noise when determining the state of the ejector section D can be suppressed. On the other hand, in the first inspection mode, comparison signals CCPc, CCP1, and CCP2 for determining the state of the ejector section D are generated based on the first portion of the signal in the residual vibration signal VD, which is a period shorter than the second period TPP2. 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 amplitude Vamp is calculated using the comparison signal CCP of the second period TPP2, which is more than half of the period of the residual vibration signal VD, but in the first inspection mode, the amplitude Vamp is calculated using the comparison signal CCP of the first period TPP1, which is less than one-quarter of the period of the residual vibration signal VD.

[0199] It should be noted that each comparison signal CCP can also be generated by methods other than the logical AND operation of the comparison signal CP corresponding to that comparison signal CCP, the inverted signal of the shielding signal MSK, and the signal Pcut during the pulse detection period.

[0200] For example, in the first check mode, the comparison signal CCPc can be generated by a latch circuit that changes the output signal from low to high when the comparison signal CPc changes from low to high, and 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 changes the output signal from low to high when the comparison signal CP1 changes from low to high, and resets the output signal to low when the signal Pcut changes from high to low during pulse detection. Furthermore, the comparison signal CCP2 can be generated by a latch circuit that changes the output signal from low to high when the comparison signal CP2 changes from low to high, and resets the output signal to low when the signal Pcut changes from high to low during pulse detection. As described above, in the aspect of generating the comparison signal CCP by the 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 the aspect of generating the comparison signal CCP by the latch circuit, for example, the blocking timing that can block the signal path of the residual vibration signal VD from the ejection section D to the signal generation section 60 is earlier than the reset timing tep.

[0201] 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.

[0202] Alternatively, for example, the connection state specifying circuit 310 of the switching circuit 31 can generate the pulse detection period signal Pcut and the shielding signal MSK. Specifically, the connection state specifying circuit 310 can also generate the pulse detection period signal Pcut and the shielding signal MSK based on at least a portion of the printed signal SI, the latch signal LAT, and the period specification signal Tsig.

[0203] Additionally, for example, with Figure 9 The logic AND of the inverted signals of the pulse detection period signal Pcut and the shielding signal MSK shown can also be used as signals that combine the pulse detection period signal Pcut and the shielding signal MSK.

[0204] Additionally, for example, in the second inspection mode, the peak value of the residual vibration signal VD and the amplitude of PK2 can also be used to determine the state of the ejection section D. In this case, the comparison circuits 620, 621, and 622, the pulse detection period signal Pcut, and the shielding signal MSK can also operate as follows.

[0205] 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 then 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 shielding signal MSK remains high from time t0 to time t15, and transitions from high to low at time t15. Then, the shielding signal MSK remains low, for example, from time t25 to time t45. Additionally, during pulse detection, the signal Pcut remains high until time t35, at which point it transitions from high to low. It should be noted that the threshold potential Vthm2 is lower than the threshold potential VthC, and the threshold potential Vthm1 is lower than the threshold potential Vthm2.

[0206] Furthermore, for example, in the second inspection mode, the amplitude of the peak value PK1 of the residual vibration signal VD can also be used to determine the state of the ejector 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 until time t25, and then change from a high level to a low level at time t25. Additionally, in the second inspection mode, when the amplitude of the peak value PK1 of the residual vibration signal VD is used to determine the state of the ejector section D, the shielding signal MSK can be omitted.

[0207] Furthermore, in the first inspection mode, the time ratios of duration TC1 to duration TCc and duration TC2 to duration TCc can also be adjusted by adjusting the reset timing tep. In this case, since the amplitude Vamp calculated according to equation (1) is adjusted, the sensitivity for determining the state of the ejector D will be adjusted. That is, in the first inspection mode, the sensitivity for determining the state of the ejector D can also be adjusted by adjusting the reset timing tep.

[0208] 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. It should be noted that... Figures 10 to 12The example illustrates the comparison of the potential of the residual vibration signal VD with the threshold potential Vth1. When comparing the potential of the residual vibration signal VD with the threshold potential Vth2, the method also involves replacing elements related to the threshold potential Vth1 with elements related to the threshold potential Vth2. Figures 10 to 12 Please provide an explanation.

[0209] Figure 10 This is an explanatory diagram illustrating 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, and the residual vibration signal VD, 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.

[0210] In addition, Figure 10 In the curve of the residual vibration signal VD, the vertical axis represents the voltage [V] relative to the threshold potential VthC, i.e., the potential difference from the threshold potential VthC, and the horizontal axis represents the elapsed time [μs] from the reference timing tref. It should be noted that the unit [μs] means 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 scenario, 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 a normal nozzle is the same as the period of the residual vibration signal VD of an abnormal nozzle, and one-quarter of the period is 2.0 μs. Figure 10 The dashed line in the graph of the residual vibration signal VD shows the slope at the threshold potential Vth1 of the residual vibration signal VD of a normal nozzle. Figure 10 In this case, we imagine that the slope at the threshold potential Vth1 of the residual vibration signal VD remains almost unchanged in both normal and abnormal nozzles.

[0211] exist Figure 10The diagram shows the comparison signals CCPc and CCP1 when the reset timing tep (where the signal Pcut transitions from high to low during pulse detection) is 2.0 μs after the reference timing tref. Additionally, in... Figure 10 In the image, a dashed line represents an example of the adjusted reset timing tep.

[0212] In both normal and abnormal nozzles, adjusting the reset timing tep will not adjust the timing tsc for the comparison signal CCPc to transition from low to high. Conversely, in both normal and abnormal nozzles, adjusting the reset timing tep adjusts the timing for the comparison signal CCPc to transition from high to low to the same timing as the reset timing tep. Therefore, in both normal and abnormal nozzles, adjusting the reset timing tep adjusts the duration TCc of the period WCc during which the comparison signal CCPc is high.

[0213] Furthermore, in both normal and abnormal nozzles, adjusting the reset timing tep will not adjust the timing ts1 of the comparison signal CCP1 transitioning from low to high. Conversely, in both normal and abnormal nozzles, adjusting the reset timing tep adjusts the timing of the comparison signal CCP1 transitioning from high to low to the same timing as the reset timing tep. Therefore, in both normal and abnormal nozzles, adjusting the reset timing tep adjusts the duration TC1 of the period WC1 during which the comparison signal CCP1 is high.

[0214] Next, refer to Figure 11 The relationship between the adjustment of the reset timing tep and the amplitude Vamp calculated based on the duration TCc and TC1 after the reset timing tep is adjusted is explained.

[0215] Figure 11 This is an explanatory diagram used to illustrate the relationship between the reset timing tep and the amplitude Vamp calculated based on the durations TCc and TC1. Figure 11 The adjusted waveform represents a sine wave, which has a duration TCc and TC1 adjusted by the reset timing tep and according to... Figure 7 The amplitude Vamp is calculated using equation (1) as described in the diagram. That is, the adjusted waveform is considered as a virtual waveform when the residual vibration signal VD has the amplitude Vamp calculated based on the durations TCc and TC1, and may not be the same waveform as the residual vibration signal VD actually output from the detection circuit 33.

[0216] exist Figure 11In the residual vibration signal VD curve and the adjusted waveform curve, the vertical axis represents the voltage [V] with the threshold potential VthC as the reference, i.e., the potential difference with the threshold potential VthC, and the horizontal axis represents the elapsed time [μs] from the reference timing tref. It should be noted that in Figure 11 In this context, the reference timing tref is the timing at which 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.

[0217] 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 described herein are the same. 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. Furthermore, the time TPH corresponding to the phase difference between the residual vibration signals VD of the normal nozzle and the abnormal nozzle is 0.5μs. Additionally, one-quarter of the period of the residual vibration signals VD of both the normal and abnormal nozzles is 2.0μs. Therefore, the residual vibration signal VD of the normal nozzle reaches its peak value PK1 after a timing interval of 2.0μs from the reference timing tref, and the residual vibration signal VD of the abnormal nozzle reaches its peak value PK1 after a timing interval of 2.5μs from the reference timing tref.

[0218] Hereinafter, the timing of the residual vibration signal VD becoming the peak value 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 a quarter of the period of the residual vibration signal VD has elapsed since the potential of the residual vibration signal VD rises from a potential lower than the threshold potential VthC to the threshold potential VthC.

[0219] exist Figure 11 The diagram shows four adjustment waveforms corresponding to four reset timings tep in each of the normal and abnormal nozzles. 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.

[0220] like Figure 11 As shown, in both normal and abnormal nozzles, when the time from the reference timing tref to the reset timing tep is long, the amplitude Vamp of the adjusted waveform increases compared to when the time from the reference timing tref to the reset timing tep is short.

[0221] For example, as described above, the peak timing of the residual vibration signal VD in a normal nozzle 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 adjusted waveform is 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 adjusted waveform is 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 adjusted waveform is approximately 1.2V, which is larger than the amplitude VPK of the residual vibration signal VD. Finally, when the reset timing tep is 3.0 μs after the reference timing tref, the amplitude Vamp of the adjusted waveform is approximately 1.5V, which is larger than the amplitude VPK of the residual vibration signal VD. It should be noted that when the reset timing tep is 3.0 μs from the reference timing tref, the amplitude Vamp of the waveform is larger than when the reset timing tep is 2.5 μs from the reference timing tref.

[0222] Furthermore, for example, as described above, the peak timing of the residual vibration signal VD from the abnormal nozzle 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 is 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 is 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 is approximately 0.5V, which is smaller than the amplitude VPK of the residual vibration signal VD. It should be noted that when the reset timing tep is 1.5μs after the reference timing tref, the amplitude Vamp of the adjusted waveform is smaller than when the reset timing tep is 2.0μs after the reference timing tref. Furthermore, when the reset timing tep is 3.0μs after the reference timing tref, the amplitude Vamp of the adjusted waveform is approximately 1.1V, which is larger than the amplitude VPK of the residual vibration signal VD.

[0223] 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 durations TCc and TC1 includes information on both the change in amplitude VPK and the change in phase. For example, the amplitude Vamp of the adjustment waveform of an abnormal nozzle includes information on the changes in both the 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. Figure 11 In the example shown, as described above, when the reset timing tep has elapsed for 2.0 μs 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. Thus, in the first inspection mode, since the change in phase difference can be derived as a change in amplitude Vamp, the parameters for determining the state of the ejection section D can be changed from two modes—amplitude VPK and phase—to a single mode—the amplitude Vamp of the adjustment waveform. Therefore, in the first inspection mode, the ejection state determination process can be performed simply.

[0224] Furthermore, in the first inspection mode, since the amplitude Vamp of the adjustment waveform of the abnormal nozzle includes information on both the change in amplitude VPK and the change in phase, it is possible to suppress 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, it is possible to suppress the decrease in accuracy of determining whether the state of the ejection section D is normal.

[0225] 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 has elapsed for 2.0μs 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 has elapsed for 2.0μs 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, the state of the ejection section D can be determined to be 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 determining the state of the ejector section D 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 of whether the ejector section D is in normal condition can be made with high accuracy. For example, if the amplitude Vamp calculated by the amplitude calculation circuit 68 is smaller than a predefined threshold amplitude based on the amplitude Vamp of the adjustment waveform of a normal nozzle, the determination circuit 69 can also determine that the ejector section D is in abnormal condition.

[0226] Furthermore, for example, when the reset timing tep has elapsed for 3.0 μs 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 are sometimes collectively referred to as the amplitude difference DV. Furthermore, hereafter, the amplitude difference between the adjustment waveform of the normal nozzle and the adjustment waveform of the abnormal nozzle is sometimes referred to as the amplitude difference DV.

[0227] exist Figure 11 In the example shown, when the time from reference timing tref to reset timing tep is long, the amplitude difference DV between the adjustment waveform of the normal nozzle and the adjustment waveform of the abnormal nozzle becomes larger compared to the case where the time from reference timing tref to reset timing tep is short.

[0228] In this way, in the first inspection mode, the sensitivity for detecting the phase change of the residual vibration signal VD can be adjusted by resetting the timing tep, so the sensitivity for determining the state of the ejection section D can be set according to the application.

[0229] Next, refer to Figure 12 The relationship between reset timing tep, amplitude Vamp, and amplitude change rate is explained.

[0230] Figure 12This is an explanatory diagram used to illustrate the relationship between the reset timing tep, the amplitude Vamp, and the rate of change of amplitude. Figure 12 The vertical axis represents the voltage [V] of amplitude Vamp relative to the threshold potential VthC, and the other side represents the amplitude change rate [%]. The horizontal axis represents the reset timing tep time [μs]. It should be noted that the amplitude change rate represents the ratio [%] of the amplitude Vamp calculated in the abnormal nozzle to the amplitude Vamp calculated in the normal nozzle. Furthermore, the reset timing tep time represents the time from the reference timing tref to the reset timing tep. Figure 10 and Figure 11 Similarly, 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. 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.

[0231] It should be noted that, in 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 circle represents the normal nozzle amplitude, Vamp. Figure 12 The black circle indicates the amplitude Vamp of the abnormal nozzle. Figure 12 The quadrilateral represents the rate of change of amplitude.

[0232] like Figure 12 As shown, in either a normal or abnormal nozzle, if the time from the reference timing tref to the reset timing tep increases, the amplitude Vamp increases. Furthermore, if the time from the reference timing tref to the reset timing tep increases, the amplitude difference DV between the amplitude Vamp of the normal nozzle and the amplitude Vamp of the abnormal nozzle increases. Additionally, in... Figure 12 In the example shown, if the time from the reference timing tref to the reset timing tep becomes longer, the absolute value of the rate of change of amplitude, which is the ratio of the amplitude Vamp of the abnormal nozzle to the amplitude Vamp of the normal nozzle, decreases because the amplitude Vamp of the normal nozzle becomes larger.

[0233] 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 extended, the amplitude difference DV between the amplitude Vamp of the normal nozzle and the amplitude Vamp of the abnormal nozzle becomes larger compared to when 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 when the amplitude difference DV is small, thus improving the accuracy of determining whether the state of the ejection section D is normal.

[0234] 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.

[0235] Alternatively, the reset timing tep can be adjusted for each nozzle N. In this aspect, 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. Furthermore, in this aspect, for example, the two ejection portions D, each having two nozzles N, correspond to a "first ejection portion" and a "second ejection portion," respectively. Moreover, in the signals corresponding to the ejection portion D of the "first ejection portion," the comparison signal CPc corresponds to a "first reference signal," comparison signals CP1 and CP2 correspond to "first check signals," 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 portion D of the "second ejection portion," the comparison signal CPc corresponds to a "second reference signal," comparison signals CP1 and CP2 correspond to "second check signals," 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."

[0236] Next, refer to Figure 13 The actions of inkjet printer 1 during the execution of ejection status determination processing are explained.

[0237] Figure 13 This is a flowchart illustrating an example of the actions of an inkjet printer 1 when performing ejection status determination processing.

[0238] 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]. It should be noted that in the following description, the case where ejector section D[j] is selected as the ejector section D to be determined will be illustrated.

[0239] Next, in step S120, the control unit 2 functions as the drive control unit 22, determining whether to determine the state of the ejector section D in the first inspection mode. For example, the drive control unit 22 may determine the inspection mode based on operation information indicating the operation performed on the inkjet printer 1. Alternatively, the drive control unit 22 may 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 performed. It should be noted that the purpose of determining the state of the ejector section D and the scenario in which the determination is performed, along with the relationship between the inspection mode, may be preset by the manufacturer of the head unit 3, etc. For example, since determining the state of the ejector section D in the first inspection mode can shorten the inspection time compared to the second inspection mode, it is effective when determining the state of the ejector section D in a short time. In addition, after the inkjet printer 1 is first started, the ink in the cavity CV is in a stagnant state, and the possibility of thickening is high. Therefore, after the inkjet printer 1 is started, the determination of the state of the ejector section D in the first inspection mode may be performed before the determination of the state of the ejector section D in the second inspection mode. Therefore, the first inspection mode can also be preset as the inspection mode after the inkjet printer 1 is started.

[0240] If the determination in step S120 is positive, that is, if the state of the ejection section D is determined in the first inspection mode, the drive control unit 22 moves the processing to step S140. On the other hand, if the determination in step S120 is negative, that is, if the state of the ejection section D is determined in the second inspection mode, the drive control unit 22 moves the processing to step S142.

[0241] In step S140, inkjet printer 1 generates a residual vibration signal VD. Although in Figure 13 Although not illustrated, the steps for generating the residual vibration signal VD include, for example, the following first and second steps. In the first step of generating the residual vibration signal VD, the control unit 2 functions as a drive control unit 22, controlling the switching circuit 31 of the head unit 3 so that the ejector section D[j] is driven as the ejector section D to be determined. 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] representing the residual vibration generated in the ejector section D[j], and generates the residual vibration signal VD[j] based on the detection signal Vout[j].

[0242] In addition, although Figure 13 Although not illustrated, step S140 includes supplying the pulse detection period signal Pcut and the shielding 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 may also supply the pulse detection period signal Pcut and the shielding signal MSK for the first inspection mode to the signal generation unit 60 of the inspection unit 6. Alternatively, the drive control unit 22 may control the switching circuit 31 of the head unit 3 to supply the pulse detection period signal Pcut and the shielding 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 moves to step S160.

[0243] 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 moves the processing to step S180.

[0244] Furthermore, as described above, if the result of the determination in step S120 is negative, the process in step S142 is executed. 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, the pulse detection period signal Pcut and the shielding signal MSK for the second inspection mode are supplied to the signal generation unit 60 of the inspection unit 6 instead of the pulse detection period signal Pcut and the shielding signal MSK for the first inspection mode. After executing the process in step S142, the inkjet printer 1 moves to step S162.

[0245] In step S162, the signal generation unit 60 of the inspection unit 6 generates comparison signals CCPc, CCP1, and CCP2 in the second inspection mode. Then, the inspection unit 6 moves the processing to step S180.

[0246] In step S180, the determination unit 67 of the determination unit 64 of the inspection unit 6 determines the duration TCc of the comparison signal CCPc, the duration TC1 of the comparison signal CCP1, and the duration TC2 of the comparison signal CCP2.

[0247] Next, in step S200, the amplitude calculation circuit 68 of the determination unit 64 of the inspection unit 6 determines the calculation mode. The method for determining the calculation mode has been described in [the previous section]. Figure 7 The explanation has already been provided, so the explanation is omitted.

[0248] 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.

[0249] If the determination in step S220 is positive, that is, if 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 moves the processing to step S260. For example, in step S240, the amplitude calculation circuit 68 calculates the amplitude Vamp based on the duration TCc and TC1.

[0250] 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 moves the processing to step S260. For example, in step S242, the amplitude calculation circuit 68 calculates the amplitude Vamp based on the durations TCc and TC2.

[0251] 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 including information representing the result of the determination. Then, the determination circuit 69 outputs the state information Cinf to the control unit 2 and ends the ejection state determination process.

[0252] It should be noted that 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 may also be performed before the processing in step S100. Alternatively, for example, the determination in step S220 may 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 shielding signal MSK for the first inspection mode to the signal generation unit 60 of the inspection unit 6 may also be included in step S160. Similarly, the step of supplying the pulse detection period signal Pcut and the shielding signal MSK for the second inspection mode to the signal generation unit 60 of the inspection unit 6 may also be included in step S162.

[0253] 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, which 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, which 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 as the comparison signal CCP corresponding to a first portion of a signal in the residual vibration signal VD during a first period TPP1; and a second inspection mode, which generates a second inspection mode signal as the comparison signal CCP corresponding to a second portion of a signal in the residual vibration signal VD during a second period TPP2. The first period TPP1 is shorter than the second period TPP2.

[0254] It should be noted that, in this embodiment, the signal generation unit 60 and the determination unit 64 are included in the head unit control module HCM, which controls the head unit 3 equipped with an ejection unit D capable of ejecting ink according to the input drive signal COM. Furthermore, in this embodiment, the method for determining the state of the ejection unit D is equivalent to a liquid ejection inspection method.

[0255] 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. 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. 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.

[0256] Furthermore, in this embodiment, the first period TPP1 may be less than one-quarter of the period of the residual vibration signal VD, and the second period TPP2 may be more than one-half of the period of the residual vibration signal VD. In this aspect, 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.

[0257] Furthermore, in this embodiment, the second period TPP2 is a period that follows the first period TPP1. The signal generation unit 60 generates a second inspection mode signal in the second inspection mode without using the first portion of the residual vibration signal VD. In this aspect, the first portion of the residual vibration signal VD, which is a period preceding the second period TPP2, is not used to determine the state of the ejector section D. Therefore, in this aspect, by determining the state of the ejector section D in the second inspection mode, even if noise is superimposed on the residual vibration signal VD immediately after it is input to the signal generation unit 60, the influence of this noise on the determination of the state of the ejector section D can be suppressed.

[0258] Furthermore, in this embodiment, the first period TPP1 may also begin before the first time elapses from when 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 when the residual vibration signal VD is input to the signal generation unit 60 to when the comparison signal CCP is generated from becoming longer. As a result, in this aspect, 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.

[0259] Furthermore, in this embodiment, the signal path of the residual vibration signal VD[j] from the ejection section D[j] to the signal generation unit 60 is blocked at the blocking timing based on the connection state specification signal Qs[j]. Moreover, in this embodiment, the determination unit 64 can also be understood to operate as follows: For example, the determination unit 64 determines the state of the ejection section D based on multiple time information NTCs, which are generated by using multiple comparison signals CP as signals to reset the signal Pcut at the reset timing tep during pulse detection. When the blocking timing is earlier than the reset timing tep, each of the multiple time information NTCs is generated by using each of the multiple comparison signals CP as a signal whose potential is maintained until the reset timing tep. In this aspect, since the period during which the residual vibration signal VD[j] from the ejection section D[j] is input to the signal generation unit 60 can be shortened, the inspection time can be shortened.

[0260] Furthermore, in this embodiment, a reset timing tep can be set for each ejector section D. In this aspect, for example, in each of the two ejector sections D, the state of that ejector section D is determined based on time information NTC, which is generated using a pulse detection period signal Pcut and a comparison signal CP that define the reset timing tep corresponding to that ejector section D. Therefore, in this aspect, for example, even if the detection of the residual vibration signal VD deviates in multiple ejector sections D, the state of each ejector section D can be determined with high accuracy.

[0261] [Second Implementation]

[0262] Figure 14 This is a block diagram illustrating an example of the configuration of the inspection unit 6A according to the second embodiment. Regarding the... Figures 1 to 13 The same elements described herein are labeled with the same reference numerals, and detailed descriptions are omitted.

[0263] The inkjet printer 1 described 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. It should be noted that, in this embodiment, a reset message Ntep is envisioned to be used instead. Figure 8 The pulse detection period signal Pcut is shown in the example. The reset information Ntep is an example of both "reset signal" and "timing information". Furthermore, in this embodiment, we envision a situation where 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 embodiment, it is not used... Figure 8 The shielding 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 inspection unit 6A will be described.

[0264] The inspection unit 6A includes a signal generation unit 60A and a determination unit 64A. The signal generation unit 60A is configured to work with the... Figure 7 The configuration of the signal generation unit 60 shown is the same after 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. In addition, 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.

[0265] 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, by approximating the waveform of the residual vibration signal VD as a sine wave, the amplitude is determined based on the amplitude calculation circuit 68 and the determination circuit 69 shown. Figure 7 The amplitude Vamp of the residual vibration signal VD is calculated using equation (1) or equation (2) as described in the text.

[0266] The timing designation circuit 65 designates the reset timing tep to the determination unit 67A by outputting reset information Ntep, which represents the reset timing tep, to the determination unit 67A. For example, the timing designation circuit 65 outputs reset information Ntep to the determination unit 67A, which indicates that from the reset timing tep, the reset timing tep is determined by the reset information Ntep. Figure 9 The time t0 shown is the time from the start of supplying the residual vibration signal VD to the signal generation unit 60A to the reset time tep. The reset information Ntep is stored, for example, in the storage unit 5. Hereinafter, the timing of starting to supply 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.

[0267] The determination unit 67A, for example, determines the duration TC from the timing ts (when the signal transitions from low to high) to the reset timing tep for each of the comparison signals CPC, CP1, and CP2. For example, the determination unit 67A includes determination circuits 670A, 671A, and 672A, which are respectively supplied with comparison signals CPC, CP1, and CP2. Furthermore, reset information Ntep is supplied to each of the determination circuits 670A, 671A, and 672A.

[0268] For example, the determining circuit 670A determines the duration TCc from the timing tsc when the comparison signal CPc transitions from low to high to the reset timing tep represented by the reset information Ntep. Specifically, for example, the determining circuit 670A measures the time from the start of the measurement timing to the timing tsc. Then, the determining circuit 670A determines the duration TCc as the difference between the time from the start of the measurement timing to the timing tsc and the time from the start of the measurement timing to the reset timing tep. The duration TCc determined by the determining circuit 670A is, for example, compared with... Figure 9 The duration TCc of WCc during which the comparison signal CCPc is high corresponds to the duration of WCc. The determination circuit 670A outputs the time information NTCc, which represents the duration TCc determined based on the comparison signal CCPc and the reset information Ntep, to the amplitude calculation circuit 68.

[0269] Additionally, for example, the determining circuit 671A determines the duration TC1 from the timing ts1 when the comparison signal CP1 transitions from a low level to a high level to the reset timing tep represented by the reset information Ntep. Specifically, for example, the determining circuit 671A measures the time from the start of measurement timing to timing ts1. Then, the determining circuit 671A determines the duration TC1 as the difference between the time from the start of measurement timing to timing ts1 and the time from the start of measurement timing to the reset timing tep. The duration TC1 determined by the determining circuit 671A is, for example, compared with... Figure 9 The duration TC1 of WC1 during which the comparison signal CCP1 is high corresponds to the period of high level. The determination circuit 671A outputs the time information NTC1, which represents the duration TC1 determined based on the comparison signal CP1 and the reset information Ntep, to the amplitude calculation circuit 68.

[0270] Additionally, for example, the determining circuit 672A determines the duration TC2 from the timing ts2 when the comparison signal CP2 transitions from low to high to the reset timing tep represented by the reset information Ntep. Specifically, for example, the determining circuit 672A measures the time from the start of measurement timing to timing ts2. Then, the determining circuit 672A determines the duration TC2 as the difference between the time from the start of measurement timing to timing ts2 and the time from the start of measurement timing to the reset timing tep. The duration TC2 determined by the determining circuit 672A is, for example, compared with... Figure 9 The duration TC2 of WC2 during which the comparison signal CCP2 is high corresponds to the period of high level. The determining circuit 672A outputs the time information NTC2, which represents the duration TC2 determined based on the comparison signal CP2 and the reset information Ntep, to the amplitude calculation circuit 68.

[0271] Here, the duration TCc is represented by timer tsc and reset timer tep, and the duration TC1 is represented by timer ts1 and reset timer tep, and the duration TC2 is represented by timer ts2 and reset timer tep, and the duration TC2 is represented by timer ts2 and reset timer tep, and the duration TC2 is represented by timer t1, and the duration TC2 is represented by timer ts2, and the duration TC2 is represented by ...ep, and the duration TC2 is represented by timer tep, and the duration TC2 is represented by timer tep, and the duration TC2 is represented by timer tep, and the duration TCc is represented by timer

[0272] TCc=tep-tsc……(9)

[0273] TC1=tep-ts1……(10)

[0274] TC2=tep-ts2……(11)

[0275] Thus, in this embodiment, it is possible to avoid generating... Figure 9 The duration TC is determined by comparing the signals CCPc, CCP1, and CCP2 shown.

[0276] It should be noted that the configuration of inspection unit 6A is not limited to... Figure 14The example shown. For instance, the timing designator circuit 65 could also be included in the control unit 2.

[0277] Alternatively, for example, the timing specifying circuit 65 may also supply the endpoint specifying signal, where the reset timing tep transitions from high to low, as reset information Ntep to the determining circuits 670A, 671A, and 672A. In this aspect, for example, the timing specifying circuit 65 measures the elapsed time from the start of the measurement timing and, at a timing point where the measurement result coincides with the time from the start of the measurement timing to the reset timing tep, 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 duration TCc. Similarly, the determining circuit 671A measures the time from timing ts1 to the reset timing tep and determines the measurement result as the duration TC1. Furthermore, the determining circuit 672A measures the time from timing ts2 to the reset timing tep and determines the measurement result as the duration TC2. In this aspect, the initial level of the endpoint specifying 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 endpoint designation signal will change from low to high at a timing earlier than the reset timing tep.

[0278] Alternatively, for example, the timing designation circuit 65 may also supply the endpoint designation signal at which the reset timing tep transitions from low to high as reset information Ntep to the determination circuits 670A, 671A, and 672A.

[0279] 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 is 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.

[0280] Next, refer to Figure 15 This section provides a summary of the adjustment of the reset timing tep.

[0281] Figure 15This is an explanatory diagram illustrating the general outline of the adjustment of the reset timing tep. The vertical axis in the diagram represents the voltage [V] of the residual vibration signal VD with ground potential as the reference, and the horizontal axis represents the elapsed time from the start of the measurement timing, for example, the elapsed time [μs] from time t0.

[0282] It should be noted that, in Figure 15 In the example shown, the first peak PK of the residual vibration signal VD is the peak PK when the potential of the residual vibration signal VD becomes a minimum. Therefore, in Figure 15 In this context, we envision comparing the potential of the residual vibration signal VD, within the range from the threshold potential VthC to the second peak PK of the residual vibration signal VD, with the threshold potential VthC and Vth1, etc. 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.

[0283] 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 bending and flying has occurred.

[0284] For example, if paper dust adheres to the vicinity of nozzle N, the surface of the ink within nozzle N is drawn up by the paper dust in the ejection direction, thus causing an abnormal bending and flight of the ink. In this case, as... Figure 15 As shown, in an abnormal nozzle with paper dust adhering near nozzle N, the period of residual vibration, i.e., the period of the residual vibration signal VD, is slightly longer compared to a normal nozzle. Figure 15 In the example shown, compared to the residual vibration signal VD of a normal nozzle, the residual vibration signal VD of an abnormal nozzle exhibits a period variation of approximately 4% and an amplitude variation of approximately 9%. Thus, when the variation of the residual vibration signal VD of an abnormal nozzle is small compared to that of a normal nozzle, it is difficult to detect abnormalities in the ejection state using methods that solely rely on 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.

[0285] For example, the durations TCc and TC1 are adjusted by adjusting the reset timing tep. This also adjusts the time ratio, which is the ratio of duration TC1 to duration TCc, and therefore also adjusts the time based on... Figure 7 The amplitude Vamp is calculated using equation (1) as described in the diagram. It should be noted that in this embodiment, since it is not necessary to actually generate [the amplitude]... Figure 9The pulse during the duration TCc of the comparison signal CCPc shown is used, thus, compared to the first embodiment described above, the time from the measurement start timing to the reset timing tep can be extended. Therefore, in this embodiment, the adjustment range when adjusting the reset timing tep can be expanded. As a result, in this embodiment, the determination accuracy when determining whether the state of the ejection section D is normal can be easily adjusted.

[0286] For example, the reset timing tep is adjusted so that, while improving the inspection accuracy of the state of the ejection section D, the time from the blocking timing to the reset timing tep is longer compared to the case of low inspection accuracy. It should be noted that, for example, the reset timing tep is adjusted so that, while shortening the inspection time of the state of the ejection section D, the time from the blocking timing to the reset timing tep is shorter compared to the case of long inspection time.

[0287] Furthermore, in this embodiment, the blocking timing at which the signal path of the residual vibration signal VD from the ejection section D[j] of the judgment object to the signal generation unit 60 is blocked is earlier than the reset timing tep. Therefore, in this embodiment, for example, even if the time from the measurement start timing to the reset timing tep is extended, the ejection section D[j] can perform other operations at a timing later than the blocking timing, independent of the reset timing tep. Alternatively, in this embodiment, the ejection section D, which is different from the ejection section D[j], can operate as the ejection section D of the judgment object at a timing later than the blocking timing, independent of the reset timing tep. 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.

[0288] It should be noted that in the aspect where the endpoint signal specifying the transition of the reset timing tep from high to low is used as the reset information Ntep, the reset timing tep of the ejector part D of the judgment object is earlier than the measurement start timing of the ejector part D of the next judgment object. However, in this aspect, since the blocking timing can also be earlier than the reset timing tep, the increase in inspection time can be suppressed. For example, in this aspect, as long as the timing is later than the blocking timing of the ejector part D of the judgment object, the drive signal COM can be supplied to the ejector part D of the next judgment object at a timing earlier than the reset timing tep of the ejector part D of the judgment object.

[0289] In addition, Figure 15 The invention envisions a scenario where the potential of the residual vibration signal VD, ranging 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, but the invention is not limited to this aspect. For example, in Figure 15In the residual vibration signal VD shown, the potential of the residual vibration signal VD within the range from the threshold potential VthC to the first peak PK of the residual vibration signal VD can also be compared with the threshold potential VthC and Vth1, etc. In this case, for example, the potential of the residual vibration signal VD can be compared with a threshold potential lower than the threshold potential VthC, for example... Figure 9 The threshold potential Vthm1 shown is compared to the residual vibration signal VD's potential with the threshold potential Vth1, instead of comparing the residual vibration signal VD's potential with the threshold potential Vth1. The method of generating the comparison signal CP based on the comparison result of a threshold potential lower than the threshold potential VthC with the residual vibration signal VD is different from... Figure 9 The method of using the threshold potential Vthm1 described in the text is the same.

[0290] Next, refer to Figure 16 The relationship between reset timing tep, amplitude Vamp, and amplitude change rate is explained.

[0291] Figure 16 This is an explanatory diagram used to illustrate the relationship between the reset timing tep, the amplitude Vamp, and the rate of change of amplitude. Figure 16 The vertical axis represents the voltage [V] of the amplitude Vamp based on the threshold potential VthC, and the other side represents the amplitude change rate [%]. The horizontal axis represents the adjustment time [μs] of the reset timing tep. It should be noted that the adjustment time of the reset timing tep represents the time (μs) from the lower limit of the reset timing tep adjustment range. However, for ease of explanation, the adjustment range of the reset timing tep and its lower limit are imported values ​​and may not be actually set. Furthermore, the amplitude change rate and... Figure 12 Similarly, this represents the ratio [%] of the amplitude Vamp calculated in an abnormal nozzle to the amplitude Vamp calculated in a normal nozzle.

[0292] Figure 16 The solid line represents the amplitude Vamp of a normal nozzle. Figure 16 The dashed line represents the amplitude Vamp of the nozzle where the ink is abnormally shaped and flies. Figure 16 The single-dotted line represents the rate of change of amplitude. Additionally, in Figure 16 In the comparative example, the values ​​of amplitude difference and amplitude change rate are shown in parentheses. 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. For example, the amplitude difference between the amplitude Vamp of the normal nozzle and the amplitude Vamp of the abnormal nozzle calculated according to the comparative example is about 0.1V, and the amplitude change rate of the comparative example is about 0.1V.

[0293] In this embodiment, such as Figure 16As shown, in both normal and abnormal nozzles, if the adjustment time of the reset timing tep increases, the amplitude Vamp increases. Furthermore, if the adjustment time of the reset timing tep increases, the amplitude difference DV between the amplitude Vamp of the normal nozzle and the amplitude Vamp of the abnormal nozzle increases. Figure 16 In the example shown, the amplitude difference relative to the comparative example is approximately 0.1V, and the amplitude difference DV can be adjusted within the range of approximately 0.2V to approximately 1.0V. Furthermore, if the adjustment time of the reset timing tep is increased, the absolute value of the rate of change of amplitude (the ratio of the amplitude Vamp of the abnormal nozzle to the amplitude Vamp of the normal nozzle) decreases. Figure 16 In the example shown, the amplitude difference relative to the comparative example is about -9%, and the amplitude change rate can be adjusted within the range of about -16% to about -42%.

[0294] 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 bending and flying can be improved.

[0295] Next, refer to Figure 17 The actions of inkjet printer 1 during the execution of ejection status determination processing are explained.

[0296] Figure 17 This is a flowchart illustrating an example of the actions of an 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, and with Figure 13 The actions shown are the same. Figure 17 The process of steps S164 and S170 will be explained in detail.

[0297] The process of step S140 is executed before the process of step S164 is executed. For example, after the inkjet printer 1 executes the process of step S140, the process is moved to step S164.

[0298] In step S164, the signal generation unit 60A of the inspection unit 6A generates comparison signals CPc, CP1, and CP2 by comparing the potential of the residual vibration signal VD with each of the threshold potentials VthC, Vth1, and Vth2. Then, the inspection unit 6A moves the processing to step S170.

[0299] In step S170, the timing designation circuit 65 of the determination unit 64A of the inspection unit 6A outputs the reset information Ntep, representing 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 moves the processing to step S180.

[0300] 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) described herein are used to determine the durations TCc, TC1, and TC2.

[0301] It should be noted that the actions of inkjet printer 1 during the ejection status determination process are not limited to... Figure 17 The example shown. For instance, the process of step S170 can be performed before the process of step S180, or it can be performed before the process of step S100.

[0302] 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, which receives a residual vibration signal VD corresponding to the residual vibration generated in the ejection section D upon 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 blocked at a blocking time 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, which are generated by using the plurality of comparison signals CP as signals to reset at a reset time tep based on reset information Ntep. When the blocking time is earlier than the reset time tep, each of the plurality of time information NTCs is generated by using each of the plurality of comparison signals CP as a signal whose potential is maintained until the reset time tep.

[0303] It should be noted that, in this embodiment, the signal generation unit 60A and the determination unit 64A are included in the head unit control module HCM, which controls the head unit 3 equipped with an ejection unit D capable of ejecting ink according to the input drive signal COM. Furthermore, in this embodiment, the method for determining the state of the ejection unit D is also equivalent to a liquid ejection inspection method.

[0304] 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 blocked at the blocking timing. Furthermore, in this embodiment, when the blocking timing is earlier than the reset timing tep, each of the multiple comparison signals CP is used as a signal whose potential at the blocking timing is maintained until the reset timing tep to generate each of the multiple time information NTCs. Therefore, in this embodiment, for example, the ejection section D[j] can perform other operations at a timing later than the blocking timing, independent of the reset timing tep. Alternatively, in this embodiment, 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 blocking timing, independent of the reset timing tep. That is, in this embodiment, for example, even if the time from the start of supplying the residual vibration signal VD to the signal generation section 60A to the reset timing tep is extended, the inspection time for determining the state of the ejection section D can be shortened.

[0305] Furthermore, in this embodiment, the reset timing tep can be adjusted so that, when the inspection time for the state of the ejection section D is shortened, the time from the blocking timing to the reset timing tep is reduced compared to the case of a long inspection time. Thus, in this aspect, by adjusting the reset timing tep, the inspection time for the state of the ejection section D can be easily shortened.

[0306] Furthermore, in this embodiment, the reset timing tep can be adjusted so that, while improving the inspection accuracy of the state of the ejection section D, the time from the blocking timing to the reset timing tep is longer compared to the case of low inspection accuracy. Thus, in this aspect, by adjusting the reset timing tep, the inspection accuracy of the state of the ejection section D can be easily improved. For example, if the time from the blocking timing to the reset timing tep is longer, the time from the timing of supplying the residual vibration signal VD to the signal generation unit 60A to the reset timing tep is also longer. Therefore, when the time from the blocking timing to the reset timing tep is adjusted to be longer, the amplitude of the adjustment waveform based on the sine wave of the multiple comparison signals CP increases, thereby increasing the resolution and improving the inspection accuracy.

[0307] Furthermore, in this embodiment, the signal generation unit 60A may also generate multiple comparison signals CP based on the signal in a portion of the first period TPP1, which is less than one-quarter of the period of the residual vibration signal VD. In this way, the time required to generate the comparison signals CP can be shortened, thereby reducing the inspection time for determining the state of the ejection section D.

[0308] Furthermore, in this embodiment, the signal generation unit 60A is non-electrically connected to the ejector unit D[j] via the connection state specification signal Qs[j]. For example, in this embodiment, the wiring Li[j] is non-electrically connected to the wiring Ls according to the connection state specification signal Qs[j]. Thus, in this embodiment, since the signal generation unit 60A is non-electrically connected to the ejector unit D[j] via the connection state specification signal Qs[j], the ejector unit D[j] can perform other operations before the determination of the state of the ejector unit D[j] is completed. Alternatively, in this embodiment, before the determination of the state of the ejector unit D[j] is completed, the ejector unit D that is different from the ejector unit D[j] and is the object of determination can be operated.

[0309] Alternatively, in this embodiment, multiple comparison signals CP can be generated based on the signal in 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 begins before a first time elapses from when the residual vibration signal VD is input 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 aspect, it is possible to suppress the time from when the residual vibration signal VD is input to the signal generation unit 60A until the generation of the comparison signals CP from becoming longer. As a result, in this aspect, the inspection time for determining the state of the ejection section D can be shortened.

[0310] [Third Implementation Method]

[0311] Figure 18 This is a block diagram illustrating an example of the configuration of the inspection unit 6B according to the third embodiment. Regarding the... Figures 1 to 17 The same elements described herein are labeled with the same reference numerals, and detailed descriptions are omitted.

[0312] The inkjet printer 1 described in this embodiment, except for having an inspection unit 6B 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, similar to the second embodiment described above, it is envisioned 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 8The shielding 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 inspection unit 6B will be described.

[0313] In inspection unit 6B, reset information Ntec, Nte1, and Nte2 are used instead of Figure 14 The reset information Ntep is shown. 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 each examples of "reset signal" and "timing information." 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.

[0314] In addition to having a decision unit 64B to replace the inspection unit 6B Figure 14 Apart from the determination unit 64A shown, and Figure 14 The inspection unit 6A shown is the same. For example, the inspection unit 6B has a signal generation unit 60A and a determination unit 64B. The signal generation unit 60A is the same as... Figure 14 The signal generation unit 60A shown is the same. For example, in this embodiment, similar to 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.

[0315] The determination unit 64B replaces the timing designation circuit 66 and the determination unit 67B. Figure 14 Apart from the timing designation circuit 65 and the determination unit 67A shown, and... Figure 14 The determination unit 64A shown is the same. For example, the determination unit 64B has 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 the same as those shown. Figure 7 The amplitude calculation circuit 68 and the determination circuit 69 shown are the same. For example, by approximating the waveform of the residual vibration signal VD as a sine wave, the amplitude is determined based on the amplitude calculation circuit 68 and the determination circuit 69 shown. Figure 7 The amplitude Vamp of the residual vibration signal VD is calculated using equation (1) or equation (2) as described in the text.

[0316] The determination unit 67B has determination circuits 670B, 671B, and 672B to replace... Figure 14Apart from the circuits 670A, 671A, and 672A shown, and... 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 timing tec instead of a reset timing tep to determine the duration TCc. The determination circuit 671B is the same as the determination circuit 671A, except that it uses a reset timing te1 instead of a reset timing tep to determine the duration TC1. The determination circuit 672B is the same as the determination circuit 672A, except that it uses a reset timing te2 instead of a reset timing tep to determine the duration TC2.

[0317] 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 durations 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 specification circuit 66 will be explained using the case where ejection section D[j] is the ejection section D to be determined as an example.

[0318] The timing designator circuit 66 assigns a reset timing tec[j] to the determination circuit 670B by outputting the reset information Ntec[j] corresponding to the comparison signal CPC to the determination circuit 670B of the determination unit 67B. Furthermore, the timing designator circuit 66 assigns a reset timing te1[j] to the determination circuit 671B of the determination unit 67B by outputting the reset information Nte1[j] corresponding to the comparison signal CP1 to the determination circuit 671B of the determination unit 67B. Additionally, the timing designator circuit 66 assigns a reset timing te2[j] to the determination circuit 672B of the determination unit 67B by outputting the reset information Nte2[j] corresponding to the comparison signal CP2 to the determination circuit 672B of the determination unit 67B.

[0319] For example, the timing designator circuit 66 has addition units 660, 661 and 662, and multiplication units 663 and 664.

[0320] The addition unit 660 performs an addition operation on the reference period length RTCc and the reference setting timing rtsc[j], and outputs the reset information Ntec, which represents the reset timing tec[j] as the result of the addition operation, to the determination circuit 670B. It should be noted that the reference period length RTCc is a parameter defining the period length of a reference used to reduce the deviation of the amplitude Vamp in multiple ejector sections D, and is shared by the J ejector sections D. For example, the reference period length RTCc can also be set to approximately one-quarter of the period of the normal residual vibration signal VD. Information representing the reference period length RTCc is stored, for example, in the storage unit 5. Furthermore, 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 representing the reference setting timing rtsc[j] is stored, for example, in the storage unit 5 in association with the ejector section D[j].

[0321] The addition unit 661 receives the result of the multiplication operation performed by the multiplication unit 663. For example, the multiplication unit 663 performs a multiplication operation on the reference period length RTCc and the coefficient α, and outputs the result of the multiplication operation to the addition unit 661. Then, the addition unit 661 performs an addition operation on the result of the multiplication operation of the reference period length RTCc and the coefficient α and the reference setting timing rts1[j], and outputs the reset information Nte1, which represents the reset timing te1[j] as the result of the addition operation, to the determination circuit 671B. It should be noted that the reference setting timing rts1[j] is, for example, the timing ts1 when the comparison signal CP1 changes from low level to high level when the state of the ejector D[j] is normal. The information representing the reference setting timing rts1[j] is stored in the memory unit 5 in association with the ejector D[j].

[0322] Furthermore, the coefficient α is a coefficient used to adjust the sensitivity when determining the state of the ejector section D, and is defined 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 defined for each ejector section D. Alternatively, the coefficient α can also be a coefficient defined for each group including multiple ejector sections D. A group including multiple ejector sections D can be, for example, a group of multiple ejector sections D corresponding to nozzle array NL. Information representing the coefficient α is stored, for example, in storage unit 5. It should be noted that when the coefficient α is a coefficient defined for each ejector section D, the information representing the coefficient α is stored in storage unit 5 in association with the ejector section D. In addition, when the coefficient α is a coefficient defined for each group of multiple ejector sections D, the information representing the coefficient α is stored in storage unit 5 in association with the group.

[0323] The addition unit 662 receives the result of the multiplication operation performed by the multiplication unit 664. For example, the multiplication unit 664 performs a multiplication operation on the reference period length RTCc and the coefficient β, and outputs the result of the multiplication operation to the addition unit 662. Then, the addition unit 662 performs an addition operation on the result of the multiplication operation of the reference period length RTCc and the coefficient β and the reference setting timing rts2[j], and outputs the reset information Nte2, which represents the reset timing te2[j] as the result of the addition operation, to the determination circuit 672B. It should be noted that the reference setting timing rts2[j] is, for example, the timing ts2 when the comparison signal CP2 changes from low level to high level when the state of the ejector D[j] is normal. The information representing the reference setting timing rts2[j] is stored in the storage unit 5 in association with the ejector D[j].

[0324] Furthermore, the coefficient β is a coefficient used to adjust the sensitivity when determining the state of the ejector section D, and is defined to satisfy "β < 100%". For example, the coefficient β can be a coefficient shared by J ejector sections D, or it can be a coefficient defined for each ejector section D. Alternatively, the coefficient β can also be a coefficient defined for each group including multiple ejector sections D. A group including multiple ejector sections D can be, for example, a group of multiple ejector sections D corresponding to nozzle array NL. Information representing the coefficient β is stored, for example, in storage unit 5. It should be noted that when the coefficient β is a coefficient defined for each ejector section D, the information representing the coefficient β is stored in storage unit 5 in association with the ejector section D. In addition, when the coefficient β is a coefficient defined for each group of multiple ejector sections D, the information representing the coefficient β is stored in storage unit 5 in association with the group.

[0325] Here, the reset timing tec[j] is expressed by equation (12) using the reference period length RTCc and the reference setting timing rtsc[j]. Additionally, the reset timing te1[j] is expressed by equation (13) using the reference period length RTCc, the reference setting timing rts1[j], and the coefficient α. Then, the reset timing te2[j] is expressed by equation (14) using the reference period length RTCc, the reference setting timing rts2[j], and the coefficient β.

[0326] tec[j]=RTCc+rtsc[j]……(12)

[0327] te1[j]=α·RTCc+rts1[j]……(13)

[0328] te2[j]=β·RTCc+rts2[j]……(14)

[0329] As can be seen from equation (13), the reset timing te1[j] is adjusted by adjusting the coefficient α. Similarly, as can be seen from equation (14), the reset timing te2[j] is adjusted by adjusting the coefficient β.

[0330] Furthermore, using timer tsc[j] and reset timer tec[j], the duration TCc[j] is represented by equation (15); using timer ts1[j] and reset timer te1[j], the duration TC1[j] is represented by equation (16). Furthermore, using timer ts2[j] and reset timer te2[j], the duration TC2[j] is represented by equation (17).

[0331] TCc[j]=tec[j]-tsc[j]……(15)

[0332] TC1[j]=te1[j]-ts1[j]……(16)

[0333] TC2[j]=te2[j]-ts2[j]……(17)

[0334] In addition, according to equations (12) and (15), the duration TCc[j] is represented by equation (18), the duration TC1[j] is represented by equation (19) according to equations (13) and (16), and the duration TC2[j] is represented by equation (20) according to equations (14) and (17).

[0335] TCc[j]=RTCc+rtsc[j]-tsc[j]……(18)

[0336] TC1[j]=α·RTCc+rts1[j]-ts1[j]……(19)

[0337] TC2[j]=β·RTCc+rts2[j]-ts2[j]……(20)

[0338] As shown in equation (18), the duration 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 shown in equation (19), the duration 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 shown in equation (20), the duration 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 possible to avoid generating... Figure 9 The duration TC is determined by comparing the signals CCPc, CCP1, and CCP2 shown.

[0339] It should be noted that the configuration of inspection unit 6B is not limited to... Figure 18 The example shown. For example, the timing designation circuit 66 may also be included in the control unit 2. Alternatively, the timing designation circuit 66 may also be included in the determination unit 67B. In the aspect where the timing designation circuit 66 is included in the determination unit 67B, the reset timings tec[j], te1[j], and te2[j] may not be calculated, but the durations TCc[j], TC1[j], and TC2[j] may be calculated based on equations (18), (19), and (20). In addition, for example, the reset information Ntec[j], Nte1[j], and Nte2[j] may be stored in the storage unit 5 in association with the ejection unit D[j]. In this aspect, 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.

[0340] Alternatively, the signal specifying the end point of the level transition at reset timing tec[j], the signal specifying the end point of the level transition at reset timing te1[j], and the signal specifying the end point of the level transition at reset timing te2[j] can be used as reset information Ntec[j], Nte1[j], and Nte2[j], respectively.

[0341] 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 preferable that the first period TPP1 begins before a first time has elapsed since the residual vibration signal VD is 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.

[0342] Next, refer to Figure 19 The relationship between the residual vibration signal VD, the reset timing te, and the comparison signal CP is explained.

[0343] 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. It should be noted that, although in Figure 19 The subscript [j] is omitted in the text, but... Figure 19 The subscript [j] will be used appropriately in the description.

[0344] Figure 19 The time t0 represents the timing at which the residual vibration signal VD[j] begins to be supplied to the signal generation unit 60A. The timing for starting to supply the residual vibration signal VD[j] to the signal generation unit 60A is, for example,... Figure 8The connection state shown specifies the timing of the transition of signal Qs[j] from low to high. Figure 19 In this explanation, to make the description easier to understand, the comparison signal CP, etc., are explained with the connection state specification signal Qs[j] maintained at a high level. However, in this embodiment, the connection state specification signal Qs[j] can be changed from a high level to a low level, for example, during the timing between timer ts1 and reset timer te1.

[0345] In addition, Figure 19 In order to make the explanation easier to understand, in Figure 19 The parentheses within the brackets show the virtual comparison signals VCPc, VCP1, and VCP2. The comparison signals VCPc, VCP1, and VCP2 are compared with... Figure 9 The comparison signals CCPc, CCP1, and CCP2 shown correspond to each other. It should be noted that comparison signals VCPc, VCP1, and VCP2 are not actually generated signals. Comparison signal VCPc is a virtual signal after comparison signal CPc is reset at reset timer tec; comparison signal VCP1 is a virtual signal after comparison signal CP1 is reset at reset timer te1; and comparison signal VCP2 is a virtual signal after comparison signal CP2 is reset at reset timer te2. Figure 19 The comparison signals VCPc, VCP1, and VCP2 are shown when the reset timings tec, te1, and te2 are the same.

[0346] Figure 19 The duration of period Wc is from the timer tsc when the comparator signal CPc transitions from low to high to the reset timer tec, and the duration of period Wc is the same as the duration TCc. The duration of period W1 is from the timer ts1 when the comparator signal CP1 transitions from low to high to the reset timer te1, and the duration of period W1 is the same as the duration TC1. The duration of period W2 is from the timer ts2 when the comparator signal CP2 transitions from low to high to the reset timer te2, and the duration of period W2 is the same as the duration TC2.

[0347] When the ejector section D[j] is in a normal state, the duration TCc[j] from timing tsc[j] to reset timing tec[j] is consistent with the duration from reference setting timing rtsc[j] to reset timing tec[j], i.e., the reference cycle length RTCc. It should be noted that "consistent" means not only strict consistency but also differences in the degree of error, such as manufacturing errors or operational errors. Furthermore, when all J ejector sections D are in a normal state, the duration TCc[j] of all J ejector sections D is consistent with the reference cycle length RTCc shared by all J ejector sections D.

[0348] Furthermore, when the ejection section D[j] is in a normal state, the duration TC1[j] from timing ts1[j] to reset timing te1[j] is the same as the duration from reference setting timing rts1[j] to reset timing te1[j], i.e., the reference period length RTCc, multiplied by the coefficient α. Similarly, the duration TC2[j] from timing ts2[j] to reset timing te2[j] is the same as the duration from reference setting timing rts2[j] to reset timing te2[j], i.e., the reference period length RTCc, multiplied by the coefficient β.

[0349] 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].

[0350] When the reset timing te1[j] is later than the reset timing tec[j], the amplitude Vamp is determined by assuming that the residual vibration signal VD reaches the threshold potential Vth1 at a timing earlier than the actual timing ts1[j]. For example, consider the case where the reset timing te1[j] is offset to match the reset timing tec[j] while maintaining the duration from the reference setting timing rts1[j] to the reset timing te1[j]. Furthermore, this offset is set as the first offset. In this case, the reference setting timing rts1[j] is also offset to a timing before the first offset. Additionally, as in... Figure 18 As explained, the duration 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]. While maintaining the measured duration TC1, the value obtained by subtracting the timing ts1[j] from the reference setting timing is also maintained. Therefore, the timing ts1[j] is also shifted to a timing prior to the first offset. In this case, assuming that the potential of the residual vibration signal VD reaches the threshold potential Vth1 at a timing that is a first offset earlier than the actual timing ts1[j], the amplitude Vamp is determined.

[0351] Furthermore, when the reset timing te1[j] is earlier than the reset timing tec[j], the amplitude Vamp is determined by assuming that the potential of the residual vibration signal VD reaches the threshold potential Vth1 at a timing later than the actual timing ts1[j]. For example, consider the case where the reset timing te1[j] is offset to match the reset timing tec[j] while maintaining the duration from the reference setting timing rts1[j] to the reset timing te1[j]. This offset is then set as the second offset. In this case, the reference setting timing rts1[j] is also offset to a timing after the second offset. Additionally, when maintaining the measured duration TC1, the timing ts1[j] is also offset to a timing after the second offset. In this case, the amplitude Vamp is determined by assuming that the potential of the residual vibration signal VD reaches the threshold potential Vth1 at a timing two offsets later than the actual timing ts1[j].

[0352] The reset timing te2[j] is adjusted by the coefficient β, just like the reset timing te1[j]. For example, if the reset timing te2[j] is later than the reset timing tec[j], the amplitude Vamp is determined by assuming that the potential of the residual vibration signal VD reaches the threshold potential Vth2 at a timing earlier than the actual timing ts2[j]. Alternatively, if the reset timing te2[j] is earlier than the reset timing tec[j], the amplitude Vamp is determined by assuming that the potential of the residual vibration signal VD reaches the threshold potential Vth2 at a timing later than the actual timing ts2[j].

[0353] Next, refer to Figure 20 This document provides a brief overview of 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.

[0354] Figure 20 This is an explanatory diagram outlining the adjustment of sensitivity when determining the state of the ejector section D. Figure 20 The section explains the sensitivity adjustment performed by adjusting the reset timing te1. Figure 20 The residual vibration signal VD of a normal nozzle and the residual vibration signal VD of an abnormal nozzle are shown in the figure. Figure 20 The vertical axis represents the voltage [V] relative to the threshold potential VthC, i.e., the potential difference from the threshold potential VthC, and the horizontal axis represents the elapsed time [μs] from the reference timing tref. It should be noted that 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 case, we assume the potential difference between the threshold potential VthC and the threshold potential Vth1 is 0.5V. Additionally, Figure 20 The dashed line represents the slope at the threshold potential Vth1 of the residual vibration signal VD of the normal nozzle, while the dashed line represents the slope after sensitivity adjustment.

[0355] In addition, Figure 20 In this scenario, 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 scenario, 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, with one-quarter of the period being 2.0 μs. That is, in Figure 20 In this case, we imagine that only the amplitude VPK, period, and phase of the residual vibration signal VD of a normal nozzle change compared to the residual vibration signal VD of an abnormal nozzle.

[0356] When only the amplitude VPK, period, and phase change, the duration Wc of the comparison signal CPc remains constant in both normal and abnormal nozzles, while the duration W1 of the comparison signal CP1 changes. For example, the difference in duration W1 of the comparison signal CP1 between normal and abnormal nozzles is the time difference Δts1.

[0357] like Figure 20 As shown, before sensitivity adjustment, the time difference Δts1 corresponds to the change in slope near the threshold potential Vth1 of the residual vibration signal VD of the normal nozzle. 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 slope after sensitivity adjustment becomes steeper. Figure 20 In the example shown, the reset timing te1 is adjusted to be a time tc1 that is later than the reset timing tec.

[0358] For example, consider maintaining the time from the reference setting time rts1 to the reset time te1, and shifting the reset time te1 to a time prior to time tc1 to match the reset time tec. In this case, the reference setting time rts1 is also shifted to a time prior to time tc1. Furthermore, due to the maintained time difference Δts1, the timing ts1 of the abnormal nozzle is also shifted to a time prior to time tc1. Thus, as... Figure 20 As shown by the dashed line, the slope after sensitivity adjustment becomes steeper compared to before the adjustment.

[0359] Furthermore, in the method of simply amplifying the amplitude VPK of the residual vibration signal VD to make the slope steeper, the slope of the residual vibration signal VD of the abnormal nozzle also changes in the same way as the slope of the residual vibration signal VD of the normal nozzle, thus changing the time difference Δts1. Therefore, in the method of simply amplifying the amplitude VPK of the residual vibration signal VD to make the slope steeper, it is not easy to properly adjust the sensitivity when determining the state of the ejection section D.

[0360] Next, refer to Figure 21 The relationship between the reset timing te and the amplitude Vamp calculated based on the duration TC is explained.

[0361] 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 duration TC. Figure 21 The adjusted waveform represents a sine wave, which has a duration TCc adjusted by reset timer tec and a duration TC1 adjusted by reset timer te1, and according to... Figure 7 The amplitude Vamp is calculated using equation (1) as explained in the diagram. That is, the adjusted waveform is considered a virtual waveform when the residual vibration signal VD has the amplitude Vamp calculated based on the durations TCc and TC1, and may not be the same waveform as the actual residual vibration signal VD output from the detection circuit 33. Furthermore, Figure 21 The comparison signal VCPc is a virtual signal after the comparison signal CPCc is reset by the reset timer tec, and the comparison signal VCP1 is a virtual signal after the comparison signal CP1 is reset by the reset timer te1.

[0362] exist Figure 21 In the residual vibration signal VD curve and the adjusted waveform curve, the vertical axis represents the voltage [V] with the threshold potential VthC as the reference, i.e., the potential difference with the threshold potential VthC, and the horizontal axis represents the elapsed time [μs] from the reference timing tref. It should be noted that in Figure 21In this context, the reference timing tref is the timing at which 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.

[0363] 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 described herein are the same. 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 both the residual vibration signals VD of the normal nozzle and the abnormal nozzle is 2.0μs. Therefore, the residual vibration signal VD of both the normal nozzle and the abnormal nozzle reaches its peak value PK after a timing interval of 2.0μs from the reference timing tref.

[0364] exist Figure 21 The diagram shows six adjustment waveforms corresponding to six reset timings te1 for each of the normal and abnormal nozzles. It should be noted that... Figure 21 The diagram shows the adjustment waveform and the dummy comparison signal VCP1 when the reset timing te1 is offset to match the reset timing tec.

[0365] like Figure 21 As shown, by adjusting the reset timing te1, the time ratio of duration TC1 to duration TCc when the ejection section D is in a normal state is adjusted. In both normal and abnormal nozzles, when the time ratio of duration TC1 to duration TCc when the ejection section D is in a normal state is large, the amplitude Vamp of the adjustment waveform increases compared to when the time ratio is small.

[0366] For example, by adjusting in Figure 18 The coefficient α in equation (13) is used to adjust the reset timing te1. The coefficient α corresponds to the time ratio of the duration TC1 to the duration TCc when the ejection section D is in a normal state. It should be noted that, for example, by adjusting the... Figure 18 The reset timing te1 is adjusted by the coefficient α of equation (13) as explained in the text. It should be noted that the reset timing te1 can also be adjusted by adjusting the reference setting timing rts1. In adjusting the reference setting timing rts1, the time ratio of the duration TC1 to the duration TCc under the normal state of the ejection section D is also adjusted.

[0367] Here, the adjustment amount of the duration TC1 corresponding to the adjustment of the reset timing te1 is equivalent to the correction amount of the comparison signal CP1. Furthermore, although in Figure 21 Not illustrated, but the adjustment of the duration 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 duration TC1 can also be understood as the correction amount.

[0368] Next, refer to Figure 22 The relationship between the time ratio of duration TC1 to duration TCc under normal conditions of ejection section D and the amplitude Vamp and amplitude change rate is explained.

[0369] Figure 22 This is an explanatory diagram used to illustrate the relationship between the time ratio of the two durations TCc and TC1 and the amplitude Vamp and the rate of change of amplitude. Figure 22 The vertical axis represents the voltage [V] of the amplitude Vamp relative to the threshold potential VthC, and the other side represents the amplitude change rate [%). The horizontal axis represents the time ratio of duration TCc and TC1 [%). Amplitude change rate and... Figure 12 Similarly, this represents the ratio [%] of the amplitude Vamp calculated in an abnormal nozzle to the amplitude Vamp calculated in a normal nozzle. Additionally, the time ratio of duration TCc and TC1 represents the ratio [%] of duration TC1 to duration TCc when the ejection section D is in a normal state. For example, the time ratio is equivalent to... Figure 18 The coefficient α of equations (13) and (19) explained in the text.

[0370] Figure 22 The white circle represents the normal nozzle amplitude, Vamp. Figure 22 The black circle represents the amplitude Vamp of the abnormal nozzle. Figure 22 The quadrilateral represents the rate of change of amplitude.

[0371] like Figure 22 As shown, in both normal and abnormal nozzles, if the time ratio of durations TCc and TC1 increases, the amplitude Vamp also increases. Furthermore, if the time ratio of durations TCc and TC1 increases, the amplitude difference DV between the amplitudes Vamp of the normal nozzle and the abnormal nozzle also increases. Additionally, if the time ratio of durations TCc and TC1 increases, the absolute value of the rate of change of amplitude (the ratio of the amplitude Vamp of the abnormal nozzle to the amplitude Vamp of the normal nozzle) also increases. Figure 16 In the example shown, when the time ratio of duration TCc and TC1 is set to about 90%, the amplitude change rate increases to about three times the amplitude change rate when the time ratio of duration TCc and TC1 is about 67%.

[0372] Thus, in this embodiment, by adjusting the time ratio of durations TCc and TC1, such as the coefficient α, the amplitude Vamp and the amplitude change rate can be adjusted. It should be noted that the time ratio of durations 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 durations TCc and TC1 can be adjusted based on the amount of ink ejected in each of ejector section D[j] and ejector section D[i]. It should be noted that variable i is a natural number satisfying "1≤i≤J" and "i≠j". Furthermore, in the following, 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 will sometimes be marked with a subscript [i].

[0373] For example, when the amount of ink ejected from ejector section D[i] is less than that 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 that 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 from ejector section D[j], for example, the time ratio of durations TCc and TC1 can be adjusted so that the adjustment amount of amplitude Vamp[i] of ejector section D[i] is greater than that of amplitude Vamp[j] of ejector section D[j]. In this case, the time ratio of durations TCc and TC1 can also be adjusted by adjusting the coefficient α for each ejector section D. That is, the coefficient α can also 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".

[0374] It should be noted that in the above examples, the ejector D[j] is an example of a "first ejector," and the ejector D[i] is an example of a "second ejector." Additionally, the residual vibration signal VD[j] is an example of a "first residual vibration signal," and the residual vibration signal VD[i] is an example of a "second residual vibration signal." The comparison signal CPc[j] of the ejector D[j] is an example of a "first reference signal," and the comparison signals CP1[j] and CP2[j] of the ejector D[j] are examples of "first inspection signals." The timing information NTCc[j] of the ejector D[j] is an example of "first reference signal information," and the timing information NTC1[j] and NTC2[j] of the ejector D[j] are examples of "first inspection signal information." Furthermore, the information indicating the reference setting timing rts1[j] and the information indicating 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 indicating the reference setting timing rts1[i] and the information indicating 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 indicating the coefficient α may not be included in the "first correction information" and the "second correction information".

[0375] In this embodiment, as described above, in each of the ejection section D[j] and ejection section D[i], the time ratio of duration TCc and TC1 can be adjusted 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.

[0376] Next, refer to Figure 23 An example of the deviation between nozzles N based on the amplitude Vamp calculated from the durations TCc and TC1 is given.

[0377] Figure 23 This is an illustrative diagram illustrating an example of the deviation between nozzles N based on the amplitude Vamp calculated from durations TCc and TC1. Figure 23 The results obtained through experiments are shown in the figure. Figure 23 The vertical axis represents the voltage [V] relative to the threshold potential VthC, i.e., the potential difference from the threshold potential VthC, and the horizontal axis represents the nozzle number used to identify the J nozzles N. Additionally, in Figure 23A comparative example is shown, in which the nozzle misalignment is not adjusted, but 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. In the comparative example, the deviation ΔVex of the amplitude Vamp among the J nozzles N is about 2V, and the amplitude change rate is about -10%.

[0378] In this embodiment, since the reset timing te is adjusted for each ejection section D, the durations TCc and TC1 under normal conditions for the ejection section D each become approximately the same value in the J nozzles N corresponding to the J ejection sections D. Therefore, as follows... Figure 23 As shown, the amplitude Vamp calculated based on the durations 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. It should be noted that due to environmental changes such as temperature variations, deviations from repeated measurements, and the deterioration of the piezoelectric element PZ over time, 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%.

[0379] Thus, in this embodiment, compared to the comparative example, the deviation ΔVamp of the amplitude Vamp in the J nozzles N can be significantly reduced while improving the amplitude change rate. Furthermore, in this embodiment, for example, by adjusting the coefficient α, the sensitivity in determining the state of the ejection section D can be improved while reducing the deviation ΔVamp of the amplitude Vamp in the J nozzles N.

[0380] Next, refer to Figure 24 An example of the amplitude Vamp calculated when the sensitivity of determining the state of the ejection section D is adjusted will be explained.

[0381] 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 amplitude Vamp is shown when the sensitivity for determining the state of the ejector D is adjusted by adjusting the time ratio of the duration TCc and TC1 under normal conditions of the ejector D. Figure 24 In this scenario, we envision a coefficient α shared by J ejector sections D, where the time ratio of duration TCc and TC1 is adjusted by modifying this coefficient α.

[0382] like Figure 24As shown, under any of the following conditions where the time ratio of duration TCc to TC1 is approximately 70%, 80%, and 90%, the deviation ΔVamp of the amplitude Vamp in the J nozzles N is approximately 0. Furthermore, in Figure 24 In the example shown, as in Figure 22 As explained, if the time ratio of duration 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 will increase.

[0383] Next, refer to Figure 25 The actions of inkjet printer 1 during the execution of ejection status determination processing are explained.

[0384] Figure 25 This is a flowchart illustrating an example of the actions of an inkjet printer 1 when performing ejection status determination processing. Figure 25 The actions shown replace the series of processes in steps S172, S174, and S176. Figure 17 Apart from the processing in step S170 shown, and Figure 17 The actions shown are the same. Figure 25 In this paper, taking the case where the ejection part D of the determined object is ejection part D[j] as an example, a series of processes in steps S172, S174 and S175 will be explained.

[0385] After the processing in step S164 is executed, the timing designation circuit 66 of the determination unit 64B of the inspection unit 6B executes a series of processes in steps S172, S174, and S175. For example, after the inkjet printer 1 executes the processing in step S164, the processing moves to step S172.

[0386] In step S172, the timing specifying circuit 66 acquires information representing the reference period length RTCc, information representing the coefficient α, and information representing the coefficient β. For example, the timing specifying circuit 66 reads the information representing the reference period length RTCc, the information representing the coefficient α, and the information representing the coefficient β from the storage unit 5. Then, the checking unit 6B moves the processing to step S174.

[0387] In step S174, the timing specification circuit 66 acquires information about the reference setting timing rtsc[j], rts1[j], and rts2[j] of the ejection section D[j] representing the object to be determined. For example, the timing specification circuit 66 reads the information about the reference setting timing rtsc[j], rts1[j], and rts2[j] from the storage unit 5. Then, the inspection unit 6B moves the processing to step S176.

[0388] In step S176, the timing designation circuit 66 calculates the reset timings 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 are used to calculate the reset timings tec[j], te1[j], and te2[j]. Then, the timing designator circuit 66 outputs the reset information Ntec[j] representing the reset timing tec[j], the reset information Nte1[j] representing the reset timing te1[j], and the reset information Nte2[j] representing 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 6B moves the processing to step S180.

[0389] In step S180, the determination unit 67B of the determination unit 64B of the inspection unit 6B is based, for example, on the determination unit 67B of the inspection unit 6B. Figure 18 Equations (15), (16), and (17) described herein are used to determine the durations TCc[j], TC1[j], and TC2[j].

[0390] It should be noted that 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 S176 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 each of the coefficients α and β is shared in J ejector sections D, the process in step S172 can be performed before the process in step S100. Alternatively, the reference period length RTCc, coefficients α and β can be preset in the timing designation circuit 66. In this case, step S172 is omitted. In addition, for example, if each of the coefficients α and β is determined for each ejector section D, in step S172, the timing designation circuit 66 obtains information on the coefficients α and β of the ejector section D[j] representing the object to be determined.

[0391] Alternatively, for example, the processing of step S172 and the processing of step S174 can be not strictly distinguished. Alternatively, for example, the processing of step S176 and the processing of step S180 can be not strictly distinguished. For example, the checking unit 6B may not calculate the reset timing tec[j], te1[j], and te2[j], but based on... Figure 18The durations TCc[j], TC1[j], and TC2[j] are determined using equations (18), (19), and (20) as described herein. In this aspect, for example, the timing designator circuit 66 may output information indicating the reference period length RTCc, information indicating the coefficient α, and information indicating the coefficient β to the determination unit 67B in step S172. Then, in step S174, the timing designator circuit 66 may also output information indicating 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.

[0392] 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 received, 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 received; 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 indicating the reference setting timing rts1[j] and information indicating the reference setting timing rts1[i]. The determination unit 64B determines the state of the ejection section D[j] by using the reference setting timing rts1[i] and the timing information NTC1[j] generated based on the comparison signal CP1[j] instead of the reference setting timing rts1[i]. It also determines the state of the ejection section D[i] by using the reference setting timing rts1[i] and the timing information NTC1[i] generated based on the comparison signal CP1[i] instead of the reference setting timing rts1[j].

[0393] It should be noted that, in this embodiment, the signal generation unit 60A and the determination unit 64B are included in the head unit control module HCM, which controls the head unit 3 equipped with ejection units D[j] and D[i] capable of ejecting ink according to the input drive signal COM. Furthermore, in this embodiment, the method for determining the state of ejection units D[j] and D[i] is also equivalent to a liquid ejection inspection method.

[0394] Thus, in this embodiment, a reference setting timing rts1[j] for generating time information NTC1[j] and a reference setting timing rts1[i] for generating time information NTC1[i] are prepared respectively. Therefore, in this embodiment, deviations in the time information NTC1, or more accurately, the duration TC1 represented by the time information NTC1, can be suppressed between the ejector section D[j] and the ejector section D[i]. As a result, in this embodiment, the ejector section D[j] and the ejector section D[i] can be checked using the same reference. Furthermore, in this embodiment, since the deviation of the duration TC1 represented by the time information NTC1 is suppressed, it is not necessary to perform separate processing to address the deviation in the ejector section D during the process of determining using the time information NTC1. Therefore, in this embodiment, the state of the ejector section D can be checked efficiently. As a result, in this embodiment, the length of the inspection time for determining the state of the ejector section D can be suppressed. In addition, in this embodiment, the time information NTC1 is generated based on the reference setting timing 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 comparison signal CP1 that is reset based on a reference setting timing rts1, etc., can be used to generate time information NTC1. That is, in this embodiment, the inspection time for determining the state of the ejection section D can be shortened.

[0395] Furthermore, in this embodiment, time information NTC1[j] is generated based on the information after correcting the comparison signal CP1[j] using reference setting timing rts1[j], and time information NTC1[i] is generated based on the information after correcting the comparison signal CP1[i] using reference setting timing rts1[i]. When the ink ejection amount of the ejection section D[i] is less than the ink ejection amount of the ejection section D[j], the correction amount using reference setting timing rts1[i] is greater than the correction amount using reference setting timing rts1[j]. Thus, in this embodiment, the correction amount is adjusted according to the ink ejection amount in each of the ejection sections D[j] and D[i]. Therefore, in this embodiment, the ejection sections D[j] and D[i] can be checked with the same reference.

[0396] 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 that, regardless of whether the residual vibration signal VD[j] changes to be below the threshold potential Vth1, the residual vibration signal VD[j] is above the threshold potential Vth1 until the reset timing te1[j] corresponding to the reference setting timing rts1[j]. Thus, in this embodiment, by correcting the period of the comparison signal CP1[j] indicating that the residual vibration signal VD[j] is above the threshold potential Vth1, the adjustment waveform of the sine wave based on the comparison signal CP1[j] can be easily corrected. Furthermore, in this embodiment, for example, even if the time from the start of supplying the residual vibration signal VD[j] to the reset time te1[j] is extended, the inspection time for determining the state of the ejection section D[j] can be shortened.

[0397] Furthermore, in this embodiment, the signal path of the residual vibration signal VD[j] from the ejection section D[j] to the signal generation unit 60A is blocked at the blocking timing based on the connection state specification signal Qs[j]. The determination unit 64B generates time information NTC1[j] by using the comparison signal CP1[j] as a signal to reset at the reset timing te1[j] corresponding to the reference setting timing rts1[j]. When the blocking timing is earlier than the reset timing te1[j], the time information NTC1[j] is generated by using the comparison signal CP1[j] as a signal whose potential at the blocking timing is maintained until the reset timing te1[j]. Thus, in this embodiment, for example, the ejection section D[j] can perform other operations at a timing later than the blocking timing, regardless of the reset timing te1[j]. Alternatively, in this embodiment, the ejection section D[i], which is different from the ejection section D[j], can be determined to operate at a timing later than the blocking timing, regardless of the reset timing te1[j]. Therefore, in this embodiment, for example, even if the time from the start of supplying the residual vibration signal VD[j] to the reset time te1[j] is extended, the inspection time for determining the state of the ejection section D[j] can be shortened.

[0398] In addition, in this embodiment, the signal generation unit 60A may also generate comparison signals CP1[j] and CPc[j] based on the signal in a portion of the first period TPP1, which is less than one-quarter of the period of the residual vibration signal VD[j]. In this way, the time required to generate comparison signals CP1[j] and CPc[j] can be shortened, thereby shortening the inspection time for determining the state of the ejection section D[j].

[0399] Furthermore, in this embodiment, the signal generation unit 60A is non-electrically connected to the ejector unit D[j] via the connection state specification signal Qs[j]. For example, in this embodiment, the wiring Li[j] is non-electrically connected to the wiring Ls according to the connection state specification signal Qs[j]. Thus, in this embodiment, since the signal generation unit 60A is non-electrically connected to the ejector unit D[j] via the connection state specification signal Qs[j], the ejector unit D[j] can perform other operations before the determination of the state of the ejector unit D[j] is completed. Alternatively, in this embodiment, before the determination of the state of the ejector unit D[j] is completed, the ejector unit D[i], which is different from the ejector unit D[j], can be made to operate.

[0400] Alternatively, in this embodiment, comparison signals CP1[j] and CPc[j] can be generated based on the signal in a portion of the 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 when the residual vibration signal VD[j] is input to the signal generation unit 60A, and the first time is shorter than the time corresponding to one-quarter of the period of the residual vibration signal VD[j]. In this aspect, it is possible to suppress the time from when the residual vibration signal VD[j] is input to the signal generation unit 60A to when the comparison signals CP1[j] and CPc[j] are generated from becoming longer. As a result, in this aspect, the inspection time for determining the state of the ejection section D[j] can be shortened.

[0401] [2. Variations]

[0402] The above methods can be modified in various ways. Specific modifications are illustrated below. Two or more aspects selected from the following examples can be appropriately combined without contradiction. It should be noted that in the following examples of modifications, elements with the same function and implementation method are referenced in the accompanying drawings, and detailed descriptions are appropriately omitted.

[0403] [First Variation]

[0404] In the above embodiments, the inspection units 6, 6A, and 6B may also have a switching unit for switching whether to supply the residual vibration signal VD to the comparison unit 62. In this modified example, the control signal for switching whether to supply the residual vibration signal VD to the comparison unit 62, i.e., the control signal of the switching unit, may also be understood as a "blocking signal".

[0405] Figure 26 This is a block diagram illustrating an example of the configuration of the inspection unit 6C involved in the first modified example. Regarding... Figures 1 to 25 The same elements described herein are labeled with the same reference numerals, and detailed descriptions are omitted.

[0406] The inkjet printer 1 involved in this modification, in addition to having an inspection unit 6C to replace... Figure 1 In addition to the inspection unit 6 shown, and Figure 1 The inkjet printer 1 shown is the same. However, the control unit 2 replaces the timing signal TMSIG. Figure 8 The pulse detection period signal Pcut, as shown, is supplied to the inspection unit 6C. Furthermore, in this modified example, a case is envisioned where 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 modified example, the pulse detection period signal Pcut is not used. Figure 8 The shielding 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 inspection unit 6C will be described below.

[0407] 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 the same. Inverters INVc1, INVc2, INV11, INV12, INV21, and INV22 each output an inverted signal of the input signal. The determination unit 64 and... Figure 7 The determination unit 64 shown is the same.

[0408] The timing designator circuit 65A generates a blocking signal CSIG and an endpoint designator signal ESIG based on the timing signal TMSIG supplied from the control unit 2. Then, the timing designator circuit 65A outputs the blocking signal CSIG to switches SWc1, SW11, and SW21. Additionally, the timing designator circuit 65A outputs the endpoint designator signal ESIG to the adjustment unit 63.

[0409] The timing signal TMSIG is, for example, a signal that is initially low, transitions from low to high during a blocking timing, and then transitions from high to low during a reset timing te, which follows the blocking timing. That is, the timing based on the rising edge of the timing signal TMSIG is the blocking timing, and the timing based on the falling edge of the timing signal TMSIG is the reset timing tep. The blocking timing can also be, for example, based on the timing of the connection state specification signal Qs[j] transitioning from high to low.

[0410] The blocking 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. Alternatively, the blocking 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.

[0411] 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. Then, the endpoint designation signal ESIG may also transition from a low level to a high level before the start of the control period TSS2 included in the next unit period TU of the timing unit period TU that includes the timing signal TMSIG transitioning from a low level to a high level.

[0412] Thus, in this modified example, the blocking 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 through a signal line. The endpoint designation signal ESIG is an example of a "reset signal".

[0413] Switches SWc1, SW11, and SW21 switch the conduction and deconduction of the detection circuit 33 in the switching head unit 3 and the comparison unit 62 in the signal generation unit 60B based on the blocking signal CSIG. For example, when switch SWc1 is turned off, 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 blocked. Similarly, when switch SW11 is turned off, 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 blocked. Furthermore, when switch SW21 is turned off, 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 blocked.

[0414] exist Figure 26In the example shown, switches SWc1, SW11, and SW21 are turned on when the blocking signal CSIG is low and turned off when it is high. For example, when switch SWc1 is on, the residual vibration signal VD from detection circuit 33 is supplied to comparator circuit 620. Similarly, when switch SW11 is on, the residual vibration signal VD from detection circuit 33 is supplied to comparator circuit 621, and when switch SW21 is on, the residual vibration signal VD from detection circuit 33 is supplied to comparator circuit 622.

[0415] Switch SWc2, based on the blocking signal CSIG, toggles 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 blocking signal CSIG is low, switch SWc2 connects the input of inverter INVc1 to the output of comparator circuit 620; when the blocking 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, when the blocking signal CSIG changes from low to high, the output of inverter INVc2 remains at the timing potential of the transition from low to high. It should be noted that the output of inverter INVc2 is connected to the input of adjustment circuit 630 in adjustment unit 63. Therefore, when the blocking signal CSIG changes from low to high, the input of adjustment circuit 630 remains at the timing potential of the transition from low to high.

[0416] Switch SW12, based on the blocking signal CSIG, toggles 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 blocking signal CSIG is low, switch SW12 connects the input of inverter INV11 to the output of comparator circuit 621; when the blocking 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, when the blocking signal CSIG changes from low to high, the output of inverter INV12 remains at the timing potential of the transition from low to high. It should be noted that the output of inverter INV12 is connected to the input of adjustment circuit 631 in adjustment unit 63. Therefore, when the blocking signal CSIG changes from low to high, the input of adjustment circuit 631 remains at the timing potential of the transition from low to high.

[0417] Switch SW22, based on the blocking 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 blocking signal CSIG is low, switch SW22 connects the input of inverter INV21 to the output of comparator circuit 622; when the blocking 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, when the blocking signal CSIG changes from low to high, the output of inverter INV22 remains at the timing potential of the transition from low to high. It should be noted that the output of inverter INV22 is connected to the input of adjustment circuit 632 in adjustment unit 63. Therefore, when the blocking signal CSIG changes from low to high, the input of adjustment circuit 632 remains at the timing potential of the transition from low to high.

[0418] Thus, in this modified example, the signal generation unit 60B, and more specifically, the inverters INVc1 and INVc2, maintain the potential of the comparison signal CPC during the blocking timing. Similarly, the signal generation unit 60B, and more specifically, the inverters INV11 and INV12, maintain the potential of the comparison signal CP1 during the blocking timing. Similarly, the signal generation unit 60B, and more specifically, the inverters INV21 and INV22, maintain the potential of the comparison signal CP2 during the blocking timing.

[0419] Adjustment part 63 and Figure 7 The adjustment unit 63 shown also operates in the same way. However, in Figure 26 In the adjustment unit 63 shown, the outputs of the input inverters INVc2, INV12, and INV22 are used to replace the comparison signals CPc, CP1, and CP2, and the input endpoint specification signal ESIG is used to replace the pulse detection period signal Pcut. It should be noted that, as described above, the shielding signal MSK is not used in this modified example.

[0420] The adjustment circuit 630 of the adjustment unit 63 generates a comparison signal CCPc representing the logical AND 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 before the blocking timing, and is maintained at the level of the comparison signal CCPc at the blocking timing during the period from the blocking timing to the reset timing tep. Furthermore, after the reset timing tep, the comparison signal CCPc remains at a low level. The adjustment circuits 631 and 632 of the adjustment unit 63 also operate in the same manner as the adjustment circuit 630. Thus, the signal generation unit 60B generates comparison signals CCPc, CCP1, and CCP2 by assuming the potential of the residual vibration signal VD at the blocking timing is maintained.

[0421] It should be noted that the configuration of inspection unit 6B is not limited to... Figure 26 The example shown. For example, the timing designator circuit 65A can also be provided 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.

[0422] 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 the 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 aspect, since the latch circuit maintains the level of the comparison signal CP during the blocking timing, switches SWc1, SW11, and SW21, and inverters INVc1, INVc2, INV11, INV12, INV21, and INV22 can be omitted.

[0423] Alternatively, for example, a latch circuit that maintains the level of the comparison signal CP during the blocking timing can be used to replace switches SWc1, SW11 and SW21, inverters INVc1, INVc2, INV11, INV12, INV21 and INV22.

[0424] Additionally, the endpoint designation signal ESIG can also be supplied to the determination unit 67 of the determination unit 64. In this aspect, 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 aspect, 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 duration TCc. The determination circuits 671 and 672 of the determination unit 67 also operate in the same manner as the determination circuit 670.

[0425] Alternatively, for example, the reset timing tep, i.e. the timing when the timing signal TMSIG changes from high to low, can also be adjusted for each nozzle N.

[0426] Furthermore, the polarities of the timing signal TMSIG, the blocking signal CSIG, and the endpoint specification signal ESIG can be appropriately defined based on the characteristics of each element, such as switch SWc1. For example, the timing signal TMSIG can also be a signal that is initially high, transitions from high to low during the blocking timing, and transitions from low to high during the reset timing te.

[0427] In this modified example, the same effect as the above-described implementation method can also be obtained.

[0428] Furthermore, in this modified example, the signal generation unit 60B maintains the respective levels of the comparison signals CPc, CP1, and CP2 during the blocking timing. Therefore, in this modified example, the time from when the residual vibration signal VD is input to the signal generation unit 60B until the blocking timing is reached can be shortened. Consequently, in this modified example, the inspection time for determining the state of the ejection section D can be easily shortened.

[0429] 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 respectively based on the input of the endpoint designation signal ESIG. It should be noted that the input of the endpoint designation signal ESIG, for example, means that the level of the endpoint designation signal ESIG changes from a high level to a low level. Thus, in this modified example, the reset of the comparison signals CCPc, CCP1, and CCP2 is controlled by the endpoint designation signal ESIG. Therefore, in this modified example, for example, compared to resetting the comparison signals CCPc, CCP1, and CCP2 after a predetermined time elapsed from the input blocking signal CSIG, the comparison signals CCPc, CCP1, and CCP2 can be easily adjusted. As a result, in this modified example, for example, compared to resetting the comparison signals CCPc, CCP1, and CCP2 after a predetermined time elapsed from the input blocking signal CSIG, the sensitivity when determining the state of the ejection unit D can be easily adjusted.

[0430] Furthermore, in this modified example, the blocking signal CSIG and the endpoint designation signal ESIG are based on the timing signal TMSIG, which is input to the signal generation unit 60B, and more specifically, the timing designation circuit 65A, via a single signal line. One of the blocking timing and 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, by defining the exclusive blocking timing and reset timing tep based on the rising and falling edges of a single timing signal TMSIG, the increase in the number of signal lines and interfaces for the signal generation unit 60B can be suppressed.

[0431] Furthermore, in this modified example, the reset timing tep can be adjusted so that, when the inspection time for the state of the ejector D is shortened, the time from the blocking timing to the reset timing tep is shorter compared to the case of a long inspection time. Thus, in this aspect, by adjusting the reset timing tep, the inspection time for the state of the ejector D can be easily shortened. For example, in this aspect, by shortening the time from the blocking timing to the reset timing tep, the duration of the output comparison signal CP can be shortened.

[0432] [Second variation]

[0433] In the above embodiments and variations, the amplitude Vamp is adjusted by adjusting the time ratio of durations TCc and TC1, but the present invention is not limited to this aspect. For example, the amplitude calculation circuit 68 may also calculate the amplitude Vamp by treating the threshold potential Vth1 as a correction potential that is different from the actual potential.

[0434] Specifically, in the above implementation, for example, when calculating based on durations TCc and TC1... Figure 10 In the case of the amplitude Vamp of the residual vibration signal VD shown, Figure 7 In the example described in Equation (1), the threshold potentials Vth1 and VthC are substituted with "0.5" and "0", respectively. In contrast, in this modified example, for example, "0" is substituted into the threshold potential VthC in Equation (1), and a value larger than 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 representing the correction potential is, for example, stored in the storage unit 5. The correction information representing the correction potential used to determine the state of the ejection section D[j] is an example of "first correction information", and the correction information representing the correction potential used to determine the state of the ejection section D[i] is an example of "second correction information".

[0435] 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 adjustment is made in a way that increases the amplitude Vamp calculated based on the durations TCc and TC1.

[0436] 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 adjustment is made in a way that reduces the amplitude Vamp calculated based on the durations TCc and TC1.

[0437] 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 is different from the actual potential, and the amplitude Vamp calculated based on the durations TCc and TC1 is adjusted. 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. In addition, 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 durations TCc and TC1 can be performed.

[0438] 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 received, 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 received, generates a comparison signal CP1[j] and a comparison signal CPc[j] based on the residual vibration signal VD[i], and generates a comparison signal CPc[j] based on the 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. In this case, comparison signals CP1[i] and CPc[i] are generated based on the residual vibration signal VD[i]. The storage unit stores first correction information for the comparison signal CP1[j] and a second signal for the comparison signal CP1[i]. The determination unit 64B determines the state of the ejection section D[j] using the first correction information, the comparison signal CP1[j], and the comparison signal CPc[j] without using the second correction information, and determines the state of the ejection section D[i] using the second correction information, the comparison signal CP1[i], and the comparison signal CPc[i]. The comparison signal CPc[j] indicates whether the residual vibration signal VD[j] is above the threshold potential VthC, and 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. 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 first correction information to determine the state of the ejection unit D[j].

[0439] In this modified example, the same effect 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.

[0440] [Third variation]

[0441] In the third embodiment described above, an example was illustrated where the reset timings tec, te1, and te2 are adjusted for each ejector section D, but the present invention is not limited to this aspect. For example, each of the reset timings tec, te1, and te2 may be defined for each group comprising a plurality of ejector sections D. A group comprising a plurality of ejector sections D may, for example, be a group of a plurality of 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.

[0442] [Fourth variation]

[0443] In the above embodiments and modifications, the piezoelectric element PZ is shown to shift in the Z1 direction as the potential of the independent drive signal Vin[j] changes from low to high. However, the present invention is not limited to this aspect. For example, a piezoelectric element PZ that shifts in the Z1 direction as the potential of the independent drive signal Vin[j] changes from high to low may also be used. In this case, for example, the potential of the drive signal COM changes from low to high in the portion corresponding to the expansion element and from high to low 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.

[0444] [Fifth Variation]

[0445] In the above embodiments and modifications, each head unit 3 is illustrated as having one nozzle row NL, but the present invention is not limited to this aspect. 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.

[0446] [Sixth Variation]

[0447] In the above embodiments and modifications, the inkjet printer 1 is illustrated to have four head units 3, but the present invention is not limited to this aspect. For example, the inkjet printer 1 may have one or more but no more than 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 no more than three head units 3A, or it may have five or more head units 3A.

[0448] [Seventh Variation]

[0449] 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 the threshold potential. However, the present invention is not limited to this aspect. 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 the threshold potential. In this modification, the same effect as in the above embodiments and modifications can also be obtained.

[0450] [Eighth Variation]

[0451] In the above embodiments and modifications, a case is illustrated where multiple inspection units 6 are provided, each corresponding to one of the multiple head units 3. However, the present invention is not limited to this aspect. For example, one inspection unit 6 may be provided for multiple head units 3, or multiple inspection units 6 may be provided for one head unit 3. In this modification, the same effects as in the above embodiments and modifications can also be obtained.

[0452] [Ninth Variation]

[0453] In the above embodiments and modifications, it is assumed that the inkjet printer 1 is a serial printer. However, the present invention is not limited to this aspect. The inkjet printer 1 can also be a so-called line printer in which multiple nozzles N in the head module HM are arranged to extend wider than the width of the recording paper P. In this modification, the same effects as in the above embodiments and modifications can also be obtained.

[0454] [3. Postscript]

[0455] Based on the examples above, one can grasp the following structure, for instance.

[0456] [Postscript A1]

[0457] Appendix A1 describes 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 generating a first check mode signal corresponding to a first portion of a signal during a first period in the residual vibration signal as the status check signal; and a second check mode generating a second check mode signal corresponding to a second portion of a signal during a second period in the residual vibration signal as the status check signal, wherein the first period is a shorter period than the second period.

[0458] 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 high accuracy.

[0459] [Note A2]

[0460] The liquid ejection device described in Note A2 is the same liquid ejection device described in 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.

[0461] 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.

[0462] [Note A3]

[0463] 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 the signal generation unit generates the second inspection mode signal in the second inspection mode without using the first part of the residual vibration signal.

[0464] According to Appendix A3, by determining the state of the ejector section in the second inspection mode, even if there is noise superimposed on the residual vibration signal immediately after input to the signal generation section, the influence of the noise on the determination of the state of the ejector section can be suppressed.

[0465] [Notes A4]

[0466] The liquid ejection device mentioned in Appendix A4 is the liquid ejection device mentioned in any one of Appendix A1 to Appendix 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.

[0467] According to Appendix A4, in the first inspection mode, it is possible to suppress the time from when the residual vibration signal is input to the signal generation unit until the status inspection signal is generated from becoming longer.

[0468] [Note A5]

[0469] The head unit control circuit described in Appendix A5 is 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 status check signal based on the residual vibration signal; and a determination unit that determines the status of the jetting section based on the status check signal. The signal generation unit has: a first check mode that generates a first check mode signal corresponding to a first portion of a signal during a first period in the residual vibration signal as the status check signal; and a second check mode that generates a second check mode signal corresponding to a second portion of a signal during a second period in the residual vibration signal as the status check signal, wherein the first period is a shorter period than the second period.

[0470] According to note A5, the same effect as that of note A1 above can be obtained.

[0471] [Note A6]

[0472] The head unit control circuit mentioned in Appendix A6 is the same as the head unit control circuit mentioned in Appendix 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.

[0473] According to note A6, the same effect as note A2 above can be obtained.

[0474] [Note A7]

[0475] The head unit control circuit mentioned in Appendix A7 is the same as the head unit control circuit mentioned in Appendix A5 or Appendix A6, wherein the second period is a period later than the first period, and the signal generation unit generates the second inspection mode signal in the second inspection mode without using the first part of the residual vibration signal.

[0476] According to note A7, the same effect as that of note A3 above can be obtained.

[0477] [Note A8]

[0478] The head unit control circuit involved in Appendix A8 is the head unit control circuit involved in any one of Appendix A5 to Appendix 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.

[0479] According to note A8, the same effect as that of note A4 above can be obtained.

[0480] [Note A9]

[0481] The liquid ejection inspection method described in Appendix A9 is a liquid ejection inspection method for a liquid ejection device having an ejection section capable of ejecting liquid according to an input drive signal. It generates a state inspection signal based on a residual vibration signal corresponding to residual vibration generated in the ejection section with the input of the drive signal, and determines the state of the ejection section 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 a first period in the residual vibration signal 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 a second period in the residual vibration signal is generated as the state inspection signal. The first period is a shorter period than the second period.

[0482] According to note A9, the same effect as that of note A1 above can be obtained.

[0483] [Note A10]

[0484] The liquid ejection inspection method described in Appendix A10 is the same as the liquid ejection inspection method described in Appendix 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.

[0485] According to note A10, the same effect as note A2 above can be obtained.

[0486] [Postscript A11]

[0487] The liquid ejection inspection method described in Appendix A11 is the same as 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 without using the first part of the residual vibration signal.

[0488] According to note A11, the same effect as note A3 above can be obtained.

[0489] [Note A12]

[0490] 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.

[0491] According to note A12, the same effect as note A4 above can be obtained.

[0492] [Postscript B1]

[0493] The liquid ejection device described in Appendix B1 includes: 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, wherein the plurality of inspection signal information is generated by using the plurality of inspection signals as signals to reset at a reset timing based on a reset signal, and wherein, if the blocking timing is a timing 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 signal whose potential at the blocking timing is maintained until the reset timing.

[0494] According to Appendix B1, even if the time from the start of supplying the residual vibration signal to the signal generation unit to the reset time is extended, the inspection time for determining the state of the ejection unit can be shortened.

[0495] [Note B2]

[0496] The liquid ejection device described in Appendix B2 is the same liquid ejection device described in Appendix B1, wherein the signal generation unit maintains the potential of each of the plurality of check signals at the time of the blocking timing.

[0497] According to Appendix B2, the time from when the residual vibration signal is input to the signal generation unit until the timing of the interruption can be shortened.

[0498] [Postscript B3]

[0499] The liquid ejection device mentioned in Appendix B3 is the same liquid ejection device mentioned in Appendix B1 or Appendix B2, wherein the signal generation unit resets the potential of each of the plurality of check signals according to the input of the reset signal.

[0500] According to note B3, multiple inspection signals can be easily adjusted.

[0501] [Postscript B4]

[0502] The liquid ejection device mentioned in Appendix B4 is the liquid ejection device mentioned in any one of Appendix B1 to Appendix B3, wherein the blocking 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 blocking timing and the reset timing is based on the rising edge of the timing signal, and the other of the blocking timing and the reset timing is based on the falling edge of the timing signal.

[0503] According to Appendix B4, it is possible to suppress the increase in the number of signal lines and interfaces for the signal generation section.

[0504] [Postscript B5]

[0505] The liquid ejection device involved in Appendix B5 is the liquid ejection device involved in any one of Appendix B1 to Appendix B4, wherein the reset timing is adjusted so that, in the case of shortening the inspection time of the state of the ejection section, the time from the blocking timing to the reset timing is shorter compared to the case of a long inspection time.

[0506] According to note B5, the period for outputting multiple check signals can be shortened.

[0507] [Postscript B6]

[0508] The liquid ejection device involved in Appendix B6 is the liquid ejection device involved in any one of Appendix B1 to Appendix B5, wherein the reset timing is adjusted so that, in order to improve the inspection accuracy of the state of the ejection section, the time from the blocking timing to the reset timing is longer than that in the case of low inspection accuracy.

[0509] According to note B6, increased resolution improves inspection accuracy.

[0510] [Note B7]

[0511] The liquid ejection device mentioned in Appendix B7 is the liquid ejection device mentioned in any one of Appendix B1 to Appendix 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 in the residual vibration signal.

[0512] According to Note B7, the time required to generate multiple inspection signals can be shortened, thus reducing the inspection time for determining the state of the ejection section.

[0513] [Postscript B8]

[0514] The liquid ejection device referred to in Appendix B8 is the liquid ejection device referred to in any one of Appendix B1 to Appendix B7, wherein the signal generation unit is non-electrically connected to the ejection unit through the blocking signal.

[0515] According to Appendix B8, the ejector can perform other actions before the determination of the ejector's state is completed.

[0516] [Postscript B9]

[0517] The liquid ejection device involved in Appendix B9 is the liquid ejection device involved in any one of Appendix B1 to Appendix B8, 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, the first period starting before a first time elapses from when the residual vibration signal is input to the signal generation unit, the first time being a time shorter than one-quarter of the period of the residual vibration signal.

[0518] 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 until multiple inspection signals are generated.

[0519] [Postscript B10]

[0520] The head unit control circuit described in Appendix B10 is 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 plurality of check 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 blocked at a blocking timing based on a blocking signal. The determination unit determines the state of the jetting section based on the plurality of check signal information, which is generated by using the plurality of check signals as signals to reset at a reset timing based on a reset signal. If the blocking timing is earlier than the reset timing, each of the plurality of check signal information is generated by using each of the plurality of check signals as a signal whose potential at the blocking timing is maintained until the reset timing.

[0521] According to note B10, the same effect as that of note B1 above can be obtained.

[0522] [Postscript B11]

[0523] The head unit control circuit mentioned in Appendix B11 is the same as the head unit control circuit mentioned in Appendix B10, wherein the signal generation unit maintains the potential of each of the plurality of check signals during the blocking timing.

[0524] According to note B11, the same effect as that of note B2 above can be obtained.

[0525] [Postscript B12]

[0526] The head unit control circuit mentioned in Appendix B12 is the same as the head unit control circuit mentioned in Appendix B10 or Appendix 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.

[0527] According to note B12, the same effect as that of note B3 above can be obtained.

[0528] [Postscript B13]

[0529] The head unit control circuit mentioned in Appendix B13 is the head unit control circuit mentioned in any one of Appendix B10 to Appendix B12, wherein the blocking 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 blocking timing and the reset timing is based on the rising edge of the timing signal, and the other of the blocking timing and the reset timing is based on the falling edge of the timing signal.

[0530] According to note B13, the same effect as that of note B4 above can be obtained.

[0531] [Postscript B14]

[0532] The head unit control circuit mentioned in Appendix B14 is the head unit control circuit mentioned in any one of Appendix B10 to Appendix B13, wherein the reset timing is adjusted so that, in the case of shortening the inspection time of the state of the ejection section, the time from the blocking timing to the reset timing is shorter compared to the case of a long inspection time.

[0533] According to note B14, the same effect as that of note B5 above can be obtained.

[0534] [Postscript B15]

[0535] The head unit control circuit mentioned in Appendix B15 is the head unit control circuit mentioned in any one of Appendix B10 to Appendix B14, wherein the reset timing is adjusted so that, in order to improve the inspection accuracy of the state of the ejection section, the time from the blocking timing to the reset timing is longer than that in the case of low inspection accuracy.

[0536] According to note B15, the same effect as that of note B6 above can be obtained.

[0537] [Postscript B16]

[0538] The head unit control circuit mentioned in Appendix B16 is the head unit control circuit mentioned in any one of Appendix B10 to Appendix 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 in the residual vibration signal.

[0539] According to note B16, the same effect as that of note B7 above can be obtained.

[0540] [Postscript B17]

[0541] The head unit control circuit mentioned in Appendix B17 is the head unit control circuit mentioned in any one of Appendix B10 to Appendix B16, wherein the signal generation unit is non-electrically connected to the ejection unit through the blocking signal.

[0542] According to note B17, the same effect as that of note B8 above can be obtained.

[0543] [Postscript B18]

[0544] The head unit control circuit mentioned in Appendix B18 is the head unit control circuit mentioned in any one of Appendix B10 to Appendix B17, 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, the first period starting before a first time elapses from when the 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 residual vibration signal.

[0545] According to note B18, the same effect as that of note B9 above can be obtained.

[0546] [Postscript B19]

[0547] The liquid ejection inspection method described in Appendix B19 is a liquid ejection device equipped with an ejection section capable of ejecting liquid according to an input drive signal. The method involves inputting a residual vibration signal corresponding to residual vibration generated in the ejection section with the input of the drive signal, generating multiple inspection signals based on the residual vibration signal, and determining the state of the ejection section based on the multiple inspection signal information. The multiple inspection signal information is generated by using the multiple inspection signals as signals to be reset at a reset timing based on a reset signal. The signal path of the residual vibration signal output from the ejection section is blocked at a blocking timing based on a blocking signal. If 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.

[0548] According to note B19, the same effect as that of note B1 above can be obtained.

[0549] [Postscript B20]

[0550] The liquid ejection inspection method described in Appendix B20 is the same as the liquid ejection inspection method described in Appendix B19, wherein the potentials of the plurality of inspection signals are maintained at the time of the interruption timing.

[0551] According to note B20, the same effect as that of note B2 above can be obtained.

[0552] [Postscript B21]

[0553] The liquid ejection inspection method described in Appendix B21 is the same as 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.

[0554] According to note B21, the same effect as that of note B3 above can be obtained.

[0555] [Postscript B22]

[0556] 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 blocking signal and the reset signal are signals based on a timing signal supplied through a signal line, one of the blocking timing and the reset timing is based on the rising edge of the timing signal, and the other of the blocking timing and the reset timing is based on the falling edge of the timing signal, and the blocking timing is a timing that precedes the reset timing.

[0557] According to note B22, the same effect as that of note B4 above can be obtained.

[0558] [Postscript B23]

[0559] The liquid ejection inspection method described in Appendix B23 is a liquid ejection inspection method described in any one of Appendices B19 to B22, wherein the reset timing is adjusted so that, in the case of shortening the inspection time of the ejection part's state, the time from the blocking timing to the reset timing is shorter compared to the case of a long inspection time.

[0560] According to note B23, the same effect as that of note B5 above can be obtained.

[0561] [Postscript B24]

[0562] The liquid ejection inspection method described in Appendix B24 is a liquid ejection inspection method described in any one of Appendices B19 to B23, wherein the reset timing is adjusted so that, in order to improve the inspection accuracy of the state of the ejection part, the time from the blocking timing to the reset timing is longer compared to the case of low inspection accuracy.

[0563] According to note B24, the same effect as that of note B6 above can be obtained.

[0564] [Postscript B25]

[0565] 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.

[0566] According to note B25, the same effect as that of note B7 above can be obtained.

[0567] [Postscript B26]

[0568] The liquid ejection inspection method described in Appendix B26 is the liquid ejection inspection method described in any one of Appendices B19 to B25, wherein the signal path includes a first signal path and a second signal path, and the first signal path and the second signal path are de-electrically connected according to the blocking signal.

[0569] According to note B26, the same effect as that of note B8 above can be obtained.

[0570] [Postscript B27]

[0571] The liquid ejection inspection method described in Appendix B27 is a liquid ejection inspection method described in any one of Appendices B19 to B26, 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, the first period starting before a first time elapses from 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.

[0572] According to note B27, the same effect as that of note B9 above can be obtained.

[0573] [Postscript C1]

[0574] 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, upon receiving a first residual vibration signal corresponding to residual vibration generated in the first ejection section with the input of the drive signal, generates a first check signal and a first reference signal based on the first residual vibration signal, and upon receiving a second residual vibration signal corresponding to residual vibration generated in the second ejection section with the input of the drive signal, generates a second check signal and a second reference signal based on the second residual vibration signal; and a determination section, which determines the state of each of the first ejection section and the second ejection section; The system includes a storage unit that stores first calibration information and second calibration information. The determination unit determines the state of the first ejection section by using the first calibration information and first inspection signal information generated based on 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. It also determines the state of the second ejection section by using the second calibration information and second inspection signal information generated based on 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.

[0575] 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.

[0576] [Note C2]

[0577] The liquid ejection device described in Appendix C2 is the same as the liquid ejection device described in Appendix C1. In this device, the first inspection signal information is generated based on the information after the first inspection signal is corrected using the first correction information, and the second inspection signal information is generated based on the information after the second inspection signal is corrected using the second correction information. When the amount of liquid ejected from the second ejection section is less than the amount of liquid ejected from the first ejection section, the correction amount using the second correction information is greater than the correction amount using the first correction information.

[0578] According to Appendix C2, the first ejector section and the second ejector section can be inspected using the same reference.

[0579] [Postscript C3]

[0580] Appendix C3 describes 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 that, upon receiving a first residual vibration signal corresponding to residual vibration generated in the first ejection section with the input of the drive signal, generates a first check signal and a first reference signal based on the first residual vibration signal, and upon receiving a second residual vibration signal corresponding to residual vibration generated in the second ejection section with the input of the drive signal, generates a second check signal and a second reference signal based on the second residual vibration signal; a storage section that stores first correction information for the first check signal and second correction information for the second check signal; and a determination section. The state of the first ejector section is determined by using the first correction information, the first check signal, and the first reference signal instead of the second correction information. The state of the second ejector section is determined by using the second correction information, the second check signal, and the second reference signal instead of the first correction information. The first reference signal is a signal indicating whether the first residual vibration signal is at or above a first potential. The first check signal is a signal indicating whether the first residual vibration signal is at or 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 at or above a third potential based on the first correction information to determine the state of the first ejector section.

[0581] According to note C3, the same effect as in note C1 above 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.

[0582] [Postscript C4]

[0583] The liquid ejection device involved in Appendix C4 is the liquid ejection device involved in any one of Appendix C1 to Appendix 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 that, regardless of whether the first residual vibration signal changes to a potential less than the second potential, the first residual vibration signal is above the second potential until a first timing corresponding to the first correction information.

[0584] According to Appendix C4, even if the time from the start of supplying the residual vibration signal to the signal generation unit to the first timing is extended, the inspection time for determining the state of the first ejection unit can be shortened.

[0585] [Postscript C5]

[0586] The liquid ejection device involved in Appendix C5 is the liquid ejection device involved in any one of Appendix C1 to Appendix C4, wherein the signal path of the first residual vibration signal from the first ejection part to the signal generation part is blocked at a 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 to reset at a first timing corresponding to the first correction information. In the case that 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 that the potential at the blocking timing is maintained until the first timing.

[0587] According to Appendix C5, even if the time from the start of supplying the residual vibration signal to the signal generation unit to the first timing is extended, the inspection time for determining the state of the first ejection unit can be shortened.

[0588] [Postscript C6]

[0589] The liquid ejection device involved in Appendix C6 is the liquid ejection device involved in any one of Appendix C1 to Appendix C5, wherein the signal generation unit generates the first inspection signal and the first reference signal based on the signal in a portion of a first period less than one-quarter of the period of the first residual vibration signal in the first residual vibration signal.

[0590] According to Appendix C6, the time required to generate the first inspection signal and the first reference signal can be shortened, thereby shortening the inspection time for determining the state of the first ejection section.

[0591] [Note C7]

[0592] The liquid ejection device described in Appendix C7 is the same liquid ejection device described in Appendix C5, wherein the signal generation unit is non-electrically connected to the first ejection unit through the blocking signal.

[0593] According to Appendix C7, the first ejector can perform other actions before the determination of the state of the first ejector ends. 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 ends.

[0594] [Postscript C8]

[0595] The liquid ejection device involved in Appendix C8 is the liquid ejection device involved in any one of Appendix C1 to Appendix C7, wherein the first inspection signal and the first reference signal are generated based on a signal in 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.

[0596] According to Appendix C8, it is possible to suppress the time from when the residual vibration signal is input to the signal generation unit until the first inspection signal and the first reference signal are generated from becoming longer.

[0597] [Postscript C9]

[0598] The head unit control circuit mentioned in Appendix C9 is 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. It includes: a signal generation unit that, 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, generates a first check signal and a first reference signal based on the first residual vibration signal; and 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, generates a second check signal and a second reference signal based on the second residual vibration signal; and a determination unit that determines whether the first ejection section or the second ejection section... The system includes a state for each of the ejector sections and a storage section that stores first correction information and second correction information. The determination section determines the state of the first ejector section by using the first correction information and first inspection signal information generated based on the first inspection signal, without using the second correction information, and by using first reference signal information generated based on the first reference signal, without using the first correction information and the second correction information. The determination section determines the state of the second ejector section by using the second correction information and second inspection signal information generated based on the second inspection signal, without using the first correction information and the second correction information, 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.

[0599] According to note C9, the same effect as that of note C1 above can be obtained.

[0600] [Note C10]

[0601] The head unit control circuit involved in Appendix C10 is the same as the head unit control circuit involved in Appendix C9. In this circuit, the first inspection signal information is generated based on the information after the first inspection signal is corrected using the first correction information, and the second inspection signal information is generated based on the information after the second inspection signal is 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.

[0602] According to note C10, the same effect as note C2 above can be obtained.

[0603] [Postscript C11]

[0604] The head unit control circuit mentioned in Appendix C11 is 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. It includes: a signal generation unit that, 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, generates a first check signal and a first reference signal based on the first residual vibration signal; and 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, generates a second check signal and a second reference signal based on the second residual vibration signal; and a storage unit that stores first correction information for the first check signal and second correction information for the second check signal. The determination unit uses the first correction information, the first check signal, and the first reference signal instead of the second correction information to determine the state of the first ejection section, and uses the second correction information, the second check signal, and the second reference signal instead of the first correction information to determine the state of the second ejection section. The first reference signal is a signal indicating whether the first residual vibration signal is at or above a first potential, and the first check signal is a signal indicating whether the first residual vibration signal is at or 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 at or above a third potential based on the first correction information to determine the state of the first ejection section.

[0605] According to note C11, the same effect as note C3 above can be obtained.

[0606] [Note C12]

[0607] The head unit control circuit involved in Appendix C12 is the head unit control circuit involved in any one of Appendix C9 to Appendix 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 that, regardless of whether the first residual vibration signal changes to a potential less than the second potential, the first residual vibration signal is above the second potential until a first timing corresponding to the first correction information.

[0608] According to note C12, the same effect as note C4 above can be obtained.

[0609] [Postscript C13]

[0610] The head unit control circuit mentioned in Appendix C13 is the head unit control circuit mentioned in any one of Appendix C9 to Appendix C12, wherein the signal path of the first residual vibration signal from the first ejection section to the signal generation section is blocked at a blocking timing based on the blocking signal, and the determination section generates the first check signal information by using the first check signal as a signal to reset at a first timing corresponding to the first correction information. In the case that 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 in which the potential at the blocking timing is maintained until the first timing.

[0611] According to note C13, the same effect as note C5 above can be obtained.

[0612] [Note C14]

[0613] The head unit control circuit involved in Appendix C14 is the head unit control circuit involved in any one of Appendix C9 to Appendix C13, wherein the signal generation unit generates the first check signal and the first reference signal based on the signal in a portion of a first period less than one-quarter of the period of the first residual vibration signal in the first residual vibration signal.

[0614] According to note C14, the same effect as note C6 above can be obtained.

[0615] [Note C15]

[0616] The head unit control circuit mentioned in Appendix C15 is the same as the head unit control circuit mentioned in Appendix C13, wherein the signal generation unit is non-electrically connected to the first ejection unit through the blocking signal.

[0617] According to note C15, the same effect as note C7 above can be obtained.

[0618] [Postscript C16]

[0619] The head unit control circuit involved in Appendix C16 is the head unit control circuit involved in any one of Appendix C9 to Appendix C15, wherein the first check signal and the first reference signal are generated based on the signal in a portion of a first period less than one-quarter of the period of the first residual vibration signal in the first residual vibration signal, the first period starting before a first time has elapsed since the first residual vibration signal was input to the signal generation unit, the first time being a time shorter than the time corresponding to one-quarter of the period of the first residual vibration signal.

[0620] According to note C16, the same effect as note C8 above can be obtained.

[0621] [Postscript C17]

[0622] The liquid ejection inspection method described in Appendix C17 is a liquid ejection inspection method comprising a liquid ejection device capable of ejecting liquid according to an input drive signal. It generates a first inspection signal and a first reference signal based on a first residual vibration signal corresponding to residual vibration generated in the first ejection portion with the input of the drive signal; it generates a second inspection signal and a second reference signal based on a second residual vibration signal corresponding to residual vibration generated in the second ejection portion with the input of the drive signal; it determines the state of the first ejection portion by using the first correction information and the first inspection signal information generated based on the first inspection signal, without using the second correction information stored in the first correction information and the second correction information stored in the storage unit; it determines the state of the second ejection portion by using the second correction information and the second inspection signal information generated based on the second inspection signal, without using the first correction information and the...

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 in the ejection section as the driving signal is input, and generates multiple inspection signals based on the residual vibration signal; and The determination unit determines the state of the ejection unit. 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 the blocking signal. The determination unit The state of the ejector is determined based on multiple inspection signal information, which is generated by using the multiple inspection signals as signals to reset at a reset timing based on a reset signal. When the blocking timing is earlier than the reset timing, each of the plurality of check signal information is generated by using each of the plurality of check signals as a signal whose potential is maintained until the reset timing during the blocking timing.

2. The liquid ejection device according to claim 1, characterized in that, The signal generation unit Maintain the potential of each of the plurality of check signals during the blocking timing.

3. The liquid ejection device according to claim 2, characterized in that, The signal generation unit Based on the input of the reset signal, the potentials of the plurality of check signals are reset.

4. The liquid ejection device according to claim 2, characterized in that, The blocking signal and the reset signal are signals based on a timing signal input to the signal generation unit via a signal line. One of the blocking timing and the reset timing is based on the rising edge of the timing signal, and the other of the blocking timing and the reset timing is based on the falling edge of the timing signal.

5. The liquid ejection device according to claim 1, characterized in that, The reset timing is adjusted so that, in the case of shortening the inspection time of the state of the ejection section, the time from the blocking timing to the reset timing is shorter compared to the case of a long inspection time.

6. The liquid ejection device according to claim 1, characterized in that, The reset timing is adjusted so that, while improving the inspection accuracy of the ejection section's state, the time from the blocking timing to the reset timing is increased compared to the case of low inspection accuracy.

7. The liquid ejection device according to claim 1, characterized in that, The signal generation unit 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.

8. The liquid ejection device according to claim 1, characterized in that, The signal generation unit is non-electrically connected to the ejection unit through the blocking signal.

9. The liquid ejection device according to claim 1, characterized in that, 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 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.

10. A head unit control circuit, characterized in that, A head unit control circuit includes a jetting section capable of ejecting liquid according to an input drive signal. A signal generation unit receives a residual vibration signal corresponding to the residual vibration generated in the ejection section as the driving signal is input, and generates multiple inspection signals based on the residual vibration signal; and The determination unit determines the state of the ejection unit. 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 the blocking signal. The determination unit The state of the ejector is determined based on multiple inspection signal information, which is generated by using the multiple inspection signals as signals to reset at a reset timing based on a reset signal. When the blocking timing is earlier than the reset timing, each of the plurality of check signal information is generated by using each of the plurality of check signals as a signal whose potential is maintained until the reset timing during the blocking timing.

11. The head unit control circuit according to claim 10, characterized in that, The signal generation unit Maintain the potential of each of the plurality of check signals during the blocking timing.

12. The head unit control circuit according to claim 11, characterized in that, The signal generation unit Based on the input of the reset signal, the potentials of the plurality of check signals are reset.

13. The head unit control circuit according to claim 11, characterized in that, The blocking signal and the reset signal are signals based on a timing signal input to the signal generation unit via a signal line. One of the blocking timing and the reset timing is based on the rising edge of the timing signal, and the other of the blocking timing and the reset timing is based on the falling edge of the timing signal.

14. The head unit control circuit according to claim 10, characterized in that, The reset timing is adjusted so that, in the case of shortening the inspection time of the state of the ejection section, the time from the blocking timing to the reset timing is shorter compared to the case of a long inspection time.

15. The head unit control circuit according to claim 10, characterized in that, The reset timing is adjusted so that, while improving the inspection accuracy of the ejection section's state, the time from the blocking timing to the reset timing is increased compared to the case of low inspection accuracy.

16. The head unit control circuit according to claim 10, characterized in that, The signal generation unit 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.

17. The head unit control circuit according to claim 10, characterized in that, The signal generation unit is non-electrically connected to the ejection unit through the blocking signal.

18. The head unit control circuit according to claim 10, characterized in that, 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 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.

19. 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 residual vibration signal corresponding to the residual vibration generated in the ejection section as the drive signal is input is generated, and multiple inspection signals are generated based on the residual vibration signal. The state of the ejector is determined based on multiple inspection signal information, which is generated by using the multiple inspection signals as signals to reset at a reset timing based on a reset signal. The signal path of the residual vibration signal output from the ejector is blocked during the blocking timing based on the blocking signal. When the blocking timing is earlier than the reset timing, each of the plurality of check signal information is generated by using each of the plurality of check signals as a signal whose potential is maintained until the reset timing during the blocking timing.

20. The liquid ejection inspection method according to claim 19, characterized in that, Maintain the potential of each of the plurality of check signals during the blocking timing.

21. The liquid ejection inspection method according to claim 20, characterized in that, Based on the input of the reset signal, the potentials of the plurality of check signals are reset.

22. The liquid ejection inspection method according to claim 20, characterized in that, The blocking signal and the reset signal are signals based on a timing signal supplied through a signal line. One of the blocking timing and the reset timing is based on the rising edge of the timing signal, and the other of the blocking timing and the reset timing is based on the falling edge of the timing signal. The blocking timing is an earlier timing than the reset timing.

23. The liquid ejection inspection method according to claim 19, characterized in that, The reset timing is adjusted so that, in the case of shortening the inspection time of the state of the ejection section, the time from the blocking timing to the reset timing is shorter compared to the case of a long inspection time.

24. The liquid ejection inspection method according to claim 19, characterized in that, The reset timing is adjusted so that, while improving the inspection accuracy of the ejection section's state, the time from the blocking timing to the reset timing is increased compared to the case of low inspection accuracy.

25. The liquid ejection inspection method according to claim 19, characterized in that, 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.

26. The liquid ejection inspection method according to claim 19, characterized in that, The signal path includes a first signal path and a second signal path. According to the blocking signal, the first signal path and the second signal path are de-electrically connected.

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