Liquid ejection device and print head

Abstract

This invention provides a liquid ejection device and a printhead. The liquid ejection device, which accurately determines the ejection state in the ejection section, is characterized by comprising: a plurality of ejection sections, including a first ejection section having a first piezoelectric element driven by a drive signal and a second ejection section having a second piezoelectric element driven by a drive signal; a common liquid chamber for supplying liquid to the plurality of ejection sections; a detection unit for detecting the potential of the first piezoelectric element; and a determination unit for determining the ejection state in the first ejection section based on the detection result of the detection unit using a determination mode selected from a plurality of determination modes. When the second piezoelectric element is driven by the drive signal, the determination unit determines the ejection state in the first ejection section using a first determination mode based on the detection result of the detection unit. When the second piezoelectric element is not driven by the drive signal, the determination unit determines the ejection state in the first ejection section using a second determination mode based on the detection result of the detection unit.

Description

Technical Field

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

[0002] Liquid ejection devices such as inkjet printers eject liquids, such as ink, from nozzles by driving piezoelectric elements located in multiple ejection sections of the printhead, thereby forming an image on a medium. However, in liquid ejection devices, ejection abnormalities sometimes occur, where liquid cannot be ejected normally from the ejection sections. Therefore, techniques for determining the ejection state in the ejection sections have been proposed in the past. For example, Patent Document 1 discloses a technique for determining the ejection state in the ejection section based on the detection result of the potential of the piezoelectric elements located in the ejection section.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2020-044771

[0004] However, when determining the ejection status of one of the multiple ejection sections in the printhead, the presence or absence of the drive of the other ejection sections can affect the ejection status of that section, making accurate determination sometimes impossible. Summary of the Invention

[0005] To solve the above technical problems, the liquid ejection device of the present invention is characterized by comprising: a plurality of ejection sections, including a first ejection section and a second ejection section; the first ejection section comprising a first piezoelectric element driven by a drive signal, a first pressure chamber filled with liquid and whose volume changes according to the drive of the first piezoelectric element, and a first nozzle ejecting liquid from the first pressure chamber according to the change in volume of the first pressure chamber; the second ejection section comprising a second piezoelectric element driven by the drive signal, a second pressure chamber filled with liquid and whose volume changes according to the drive of the second piezoelectric element, and ejecting liquid from the second pressure chamber according to the change in volume of the second pressure chamber. The system includes: a second nozzle; a common liquid chamber for supplying liquid to the plurality of ejection sections; a detection unit for detecting the potential of the first piezoelectric element; and a determination unit for determining the ejection state in the first ejection section based on the detection result of the detection unit using a determination mode selected from a plurality of determination modes including a first determination mode and a second determination mode. When the second piezoelectric element is driven by the drive signal, the determination unit determines the ejection state in the first ejection section using the first determination mode based on the detection result of the detection unit. When the second piezoelectric element is not driven by the drive signal, the determination unit determines the ejection state in the first ejection section using the second determination mode based on the detection result of the detection unit.

[0006] Furthermore, the printhead according to the present invention is characterized by comprising: a plurality of ejection portions, including a first ejection portion and a second ejection portion, wherein the first ejection portion comprises a first piezoelectric element driven by a drive signal, a first pressure chamber filled with liquid and whose volume changes according to the drive of the first piezoelectric element, and a first nozzle ejecting liquid from the first pressure chamber according to the change in volume of the first pressure chamber; and the second ejection portion comprises a second piezoelectric element driven by the drive signal, a second pressure chamber filled with liquid and whose volume changes according to the drive of the second piezoelectric element, and a second nozzle ejecting liquid from the second pressure chamber according to the change in volume of the second pressure chamber. A common liquid chamber supplies liquid to the plurality of ejection sections; a detection unit detects the potential of the first piezoelectric element; and a determination unit determines the ejection state in the first ejection section based on the detection result of the detection unit using a determination mode selected from a plurality of determination modes including a first determination mode and a second determination mode. When the second piezoelectric element is driven by the drive signal, the determination unit determines the ejection state in the first ejection section based on the detection result of the detection unit using the first determination mode; when the second piezoelectric element is not driven by the drive signal, the determination unit determines the ejection state in the first ejection section based on the detection result of the detection unit using the second determination mode. Attached Figure Description

[0007] Figure 1 This is a block diagram illustrating an example of the configuration of an inkjet printer 1 according to an embodiment of the present invention.

[0008] Figure 2 This is a perspective view showing an example of the general structure of an inkjet printer 1.

[0009] Figure 3 This is a cross-sectional view illustrating an example of the structure of the ejector section D[m].

[0010] Figure 4 This is an explanatory diagram showing an example of the schematic structure of the record head 32.

[0011] Figure 5 This is a block diagram showing an example of the configuration of head unit 3.

[0012] Figure 6 This is a timing diagram illustrating an example of the signals supplied to head unit 3.

[0013] Figure 7 This is an illustrative diagram used to illustrate an example of a single specified signal Sd[m].

[0014] Figure 8 This is an illustrative diagram used to illustrate an example of a single specified signal Sd[m].

[0015] Figure 9 This is a timing diagram used to illustrate an example of the detection signal SK[m].

[0016] Figure 10 This is an explanatory diagram used to illustrate an example of the current ejection of a specified signal SG[m].

[0017] Figure 11 This is an explanatory diagram used to illustrate an example of a specified signal ST[m] being ejected in the past.

[0018] Figure 12 This is an explanatory diagram used to illustrate an example of a designated signal SR[m] emitted from adjacent jets.

[0019] Figure 13 This is a flowchart used to illustrate an example of the generation and processing of a specified signal.

[0020] Figure 14 This is an explanatory diagram used to illustrate an example of printing a specified signal SI0 and a specified signal SI.

[0021] Figure 15 This is an explanatory diagram used to illustrate an example of printing a specified signal SI0 and a specified signal SI.

[0022] Figure 16 This is an explanatory diagram used to illustrate an example of printing a specified signal SI0 and a specified signal SI.

[0023] Figure 17 This is a flowchart illustrating an example of the specified signal generation process involved in Variation Example 1.

[0024] Figure 18 This is a block diagram illustrating an example of the configuration of the inkjet printer 1B involved in Modification 5.

[0025] Explanation of reference numerals in the attached figures

[0026] 1: Inkjet printer; 2: Control unit; 3: Head unit; 4: Drive signal generation unit; 7: Conveyor unit; 8: Judgment unit; 21: Drive control unit; 22: Ejection control unit; 23: Judgment management unit; 24: Conveyor control unit; 31: Supply circuit; 32: Recording head; 33: Detection circuit. Detailed Implementation

[0027] 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 are included. However, unless otherwise specified in the following description, the scope of the present invention is not limited to these embodiments.

[0028] A. Implementation Method

[0029] In this embodiment, an inkjet printer that ejects ink to form an image on recording paper PP is used as an example to illustrate a liquid ejection device.

[0030] 1. Overview of Inkjet Printers

[0031] Below, refer to Figures 1 to 4 An example of the configuration of the inkjet printer 1 according to this embodiment will be described.

[0032] Figure 1 This is a functional block diagram illustrating an example of the configuration of an inkjet printer 1.

[0033] like Figure 1 As shown, a host computer, such as a personal computer or digital camera, supplies printing data Img, representing the image that the inkjet printer 1 should form, to the inkjet printer 1. The inkjet printer 1 performs printing processing to form the image shown in the printing data Img supplied from the host computer on recording paper PP.

[0034] like Figure 1 As shown, the inkjet printer 1 includes: a control unit 2 for controlling various parts of the inkjet printer 1; a head unit 3 for having an ink ejection section D; a drive signal generation unit 4 for generating a drive signal Com for driving the ink ejection section D; a transport unit 7 for changing the relative position of the recording paper PP with respect to the head unit 3; and a determination unit 8 for determining the ejection state of the ink in the ink ejection section D.

[0035] It should be noted that in this embodiment, inkjet printer 1 is an example of a "liquid ejection device", ink is an example of a "liquid", and determination unit 8 is an example of a "determination unit".

[0036] In this embodiment, it is envisioned that the inkjet printer 1 includes one or more head units 3, one or more drive signal generation units 4 corresponding to one or more head units 3, and one or more determination units 8 corresponding to one or more head units 3. Specifically, in this embodiment, it is envisioned that the inkjet printer 1 includes four head units 3, four drive signal generation units 4 corresponding to one of the four head units 3, and four determination units 8 corresponding to one of the four head units 3. However, for ease of explanation below, as... Figure 1 As shown, the explanation will focus on one of the four head units 3, one of the four drive signal generation units 4 corresponding to one of the head units 3, and one of the four determination units 8 corresponding to one of the head units 3.

[0037] Control unit 2 comprises one or more CPUs. However, control unit 2 may replace a CPU, or may include programmable logic devices such as FPGAs in addition to a CPU. Here, CPU is short for Central Processing Unit, and FPGA is short for Field-Programmable Gate Array. Additionally, control unit 2 includes memory. The memory comprises one or both of the following: volatile memory such as RAM (Random Access Memory); non-volatile memory such as ROM (Read Only Memory); EEPROM (Electrically Erasable Programmable Read-Only Memory); or PROM (Programmable Read-Only Memory).

[0038] The control unit 2 performs its functions as the drive control unit 21, the ejection control unit 22, the judgment management unit 23, and the delivery control unit 24 by executing the control program stored in the memory and performing actions according to the control program.

[0039] The drive control unit 21 generates a waveform specification signal dCom. 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 unit D. The drive signal generation unit 4 includes a DA conversion circuit that generates a drive signal Com having the waveform specified by the waveform specification signal dCom.

[0040] The ejection control unit 22 generates a specified signal SI. The specified signal SI is a digital signal that specifies the type of operation of the ejection unit D. Specifically, the specified signal SI specifies the type of operation of the ejection unit D by specifying whether to supply a drive signal Com to the ejection unit D for driving.

[0041] The conveying control unit 24 generates a conveying control signal MH for controlling the conveying unit 7.

[0042] like Figure 1 As shown, the head unit 3 includes a supply circuit 31, a recording head 32, and a detection circuit 33.

[0043] The recording head 32 has M ejector sections D. Here, the value M is a natural number satisfying "M≥2". It should be noted that, hereinafter, the m-th ejector section D among the M ejector sections D set in the recording head 32 is sometimes referred to as ejector section D[m]. Here, the variable m is a natural number satisfying "1≤m≤M". In addition, hereinafter, when the constituent elements or signals of the inkjet printer 1 correspond to the ejector section D[m] among the M ejector sections D, the subscript [m] is sometimes marked on the symbol used to represent the constituent element or signal.

[0044] The supply circuit 31 switches whether to supply the drive signal Com to the ejector section D[m] based on the specified signal SI. Hereinafter, the drive signal Com supplied to the ejector section D[m] in the drive signal Com is sometimes referred to as the supply drive signal Vin[m].

[0045] Based on a specified signal SI, the supply circuit 31 switches whether to supply a detection potential signal VX[m], representing the potential of the upper electrode Zu[m] of the piezoelectric element PZ[m] provided on the ejector section D[m], to the detection circuit 33. Hereinafter, when the detection potential signal VX[m] is supplied from the ejector section D[m] to the detection circuit 33, the ejector section D[m] will sometimes be referred to as the target ejector section DH. It should be noted that the piezoelectric element PZ[m] and the upper electrode Zu[m] will be discussed later. Figure 3 This will be discussed later.

[0046] The detection circuit 33 generates a detection signal SK[m] based on the detection potential signal VX[m] supplied from the ejection section D[m], which is the object of determination, via the supply circuit 31. Specifically, the detection circuit 33 generates the detection signal SK[m], for example, by amplifying the detection potential signal VX[m] and removing noise components. It should be noted that, in this embodiment, the detection circuit 33 is an example of a "detection unit".

[0047] The determination unit 8 determines whether the ink ejection state in the ejection section D[m] is normal based on the detection signal SK[m]. In other words, the determination unit 8 determines whether there is no ejection abnormality in the ejection section D[m] based on the detection signal SK[m]. In addition, the determination unit 8 generates determination information SH[m] indicating the determination result. Here, ejection abnormality refers to the general term for the state in which ink cannot be ejected normally from the nozzle N of the ejection section D[m]. For example, ejection abnormality includes the state in which ink cannot be ejected from the ejection section D[m], the state in which the ejection section D[m] ejects an amount of ink different from the amount of ink ejected by the drive signal Com, and the state in which the ejection section D[m] ejects ink at a speed different from the ink ejection speed specified by the drive signal Com, etc.

[0048] Hereinafter, the process of determining the ejection state of the ejection section D[m] based on the detection signal SK[m] will be referred to as the ejection state determination process. In this embodiment, the determination unit 8 performs the ejection state determination process by selecting a determination mode from a plurality of determination modes.

[0049] The determination management unit 23 generates a mode designation signal MS based on the designated signal SI, specifying the determination mode that the determination unit 8 should execute. The determination unit 8 performs the ejection state determination process according to the determination mode specified by the mode designation signal MS supplied from the determination management unit 23.

[0050] It should be noted that the following process will be referred to as the object-driven process: the ejection part D[m] is driven as the object ejection part DH, the detection potential signal VX[m] is detected from the ejection part D[m], and the detection signal SK[m] is generated based on the detected detection potential signal VX[m].

[0051] When performing the object determination driving process, the ejection control unit 22 generates a signal such as a specified signal SI to control the head unit 3. Additionally, when performing the object determination driving process, the drive control unit 21 generates a signal such as a waveform specified signal dCom to control the drive signal generation unit 4. Thus, the control unit 2 drives the ejection section D[m] as the object determination ejection section DH during the object determination driving process. Furthermore, during the object determination driving process, the detection circuit 33 generates a detection signal SK[m] based on the detection potential signal VX[m] detected from the ejection section D[m] driven as the object determination ejection section DH.

[0052] Furthermore, as described above, the inkjet printer 1 performs printing processing. During printing processing, the ejection control unit 22 generates a specified signal SI, etc., based on the printing data Img, to control the head unit 3. Additionally, during printing processing, the drive control unit 21 generates a waveform specified signal dCom, etc., to control the drive signal generation unit 4. Furthermore, during printing processing, the transport control unit 24 generates a transport control signal MH to control the transport unit 7. Thus, during printing processing, the control unit 2 controls the transport unit 7 in a manner that changes the relative position of the recording paper PP with respect to the head unit 3, and adjusts the presence or absence of ink ejection from the ejection unit D[m], the ink ejection amount, and the ink ejection timing, etc., to control each part of the inkjet printer 1 in a manner that forms an image corresponding to the printing data Img on the recording paper PP.

[0053] It should be noted that, in the following, printing processing and object determination driving processing are sometimes collectively referred to as ejection section driving processing.

[0054] Figure 2This is a perspective view showing an example of the general internal structure of an inkjet printer 1.

[0055] 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 feeds recording paper PP in the X1 direction and moves the head unit 3 back and forth in the Y1 direction, which intersects the X1 direction, and the Y2 direction, which is the opposite direction of the Y1 direction, while ejecting ink from the ejection section D[m], thereby forming a dot Dt on the recording paper PP corresponding to the printing data Img.

[0056] Hereinafter, the X1 direction and its opposite X2 direction will be collectively referred to as the "X-axis direction," the Y1 direction intersecting the X-axis direction and its opposite Y2 direction will be collectively referred to as the "Y-axis direction," and the Z1 direction intersecting the X-axis direction and the Y-axis direction and its opposite Z2 direction will be collectively referred to as the "Z-axis direction." In this embodiment, as an example, we will assume that the X-axis direction, Y-axis direction, and Z-axis direction are orthogonal to each other. However, the present invention is not limited to this arrangement. The X-axis direction, Y-axis direction, and Z-axis direction may intersect each other. It should be noted that in this embodiment, the Z1 direction is the direction in which ink is ejected from the ejection section D[m].

[0057] like Figure 2 As shown, the inkjet printer 1 according to this embodiment includes: a housing 100; and a carriage 110, which can reciprocate within the housing 100 in the Y-axis direction and is equipped with four head units 3.

[0058] In this embodiment, such as Figure 2 As shown, 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, as described above, it is envisioned that the inkjet printer 1 has four head units 3, each corresponding to one of the four ink cartridges 120. Each ejector section D[m] receives ink from the ink cartridge 120 corresponding to the head unit 3 on which the ejector section D[m] is located. Thus, each ejector section D[m] 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.

[0059] Furthermore, 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 Y-axis direction, a carriage guide shaft 76 for supporting the carriage 110 so that it can reciprocate freely in the Y-axis direction, a media transport mechanism 73 for transporting recording paper PP, and an impression plate 75 disposed in the Z1 direction of the carriage 110. Therefore, when performing printing processing, the transport unit 7 uses the carriage transport mechanism 71 to reciprocate the head unit 3 together with the carriage 110 along the carriage guide shaft 76 in the Y-axis direction, and uses the media transport mechanism 73 to transport the recording paper PP on the impression plate 75 in the X1 direction, thereby changing the relative position of the recording paper PP with respect to the head unit 3, so that ink can fall on the entire recording paper PP.

[0060] Figure 3 This is a schematic partial cross-sectional view of the recording head 32 after it has been cut off, including the ejection section D[m].

[0061] like Figure 3As shown, ejection unit D[m] includes a piezoelectric element PZ[m], a chamber CV[m] filled with ink therein, a nozzle N[m] communicating with the chamber CV[m], and a diaphragm 321. The ejection unit D[m] drives the piezoelectric element PZ[m] by a supply drive signal Vin[m], so that the ink in the chamber CV[m] is ejected from the nozzle N[m]. The chamber CV[m] is a space partitioned by a chamber plate 324, a nozzle plate 323 formed with the nozzle N[m], and the diaphragm 321. The chamber CV[m] communicates with a reservoir 325 via an ink supply port 326. The reservoir 325 communicates with an ink cartridge 120 corresponding to the ejection unit D[m] via an ink intake port 327. The piezoelectric element PZ[m] has an upper electrode Zu[m], a lower electrode Zd[m], and a piezoelectric body Zm[m] provided between the upper electrode Zu[m] and the lower electrode Zd[m]. The lower electrode Zd[m] is electrically connected to a power supply line Lv set to a prescribed potential VBS. Further, when the supply drive signal Vin[m] is supplied to the upper electrode Zu[m] and a voltage is applied between the upper electrode Zu[m] and the lower electrode Zd[m], the piezoelectric element PZ[m] is displaced in the Z1 direction or the Z2 direction according to the applied voltage. As a result, the piezoelectric element PZ[m] vibrates. The lower electrode Zd[m] is joined to the diaphragm 321. Therefore, when the piezoelectric element PZ[m] is vibrated by the supply drive signal Vin[m], the diaphragm 321 also vibrates. Further, by the vibration of the diaphragm 321, the volume of the chamber CV[m] and the pressure in the chamber CV[m] change, and the ink filled in the chamber CV[m] is ejected from the nozzle N[m]. It should be noted that, in the present embodiment, the chamber CV[m] is an example of a "pressure chamber", and the reservoir 325 is an example of a "common liquid chamber".

[0062] Figure 4 This is an explanatory diagram showing an example of a schematic configuration of M ejection units D[1] to D[M] provided in the recording head 32 and a reservoir 325 provided in the recording head 32.

[0063] As Figure 4 shown, in the present embodiment, M chambers CV[1] to CV[M] are provided on the recording head 32 corresponding to the M ejection units D[1] to D[M]. It should be noted that, in Figure 4 this, for ease of explanation, the variable m is described as a natural number satisfying "1 < m < M".

[0064] In this embodiment, it is envisioned that chamber CV[m] and chamber CV[m+1] are adjacent to each other via partition WL[m][m+1]. Additionally, in this embodiment, it is envisioned that chamber CV[m-1] and chamber CV[m] are adjacent to each other via partition WL[m-1][m]. Therefore, in this embodiment, when the ejector section D[m] is driven by the drive signal Com, the vibration accompanying this drive propagates to the ejector section D[m+1] via partition WL[m][m+1], and the vibration accompanying this drive also propagates to the ejector section D[m-1] via partition WL[m-1][m].

[0065] In this embodiment, the chamber CV[m] is connected to the reservoir 325 via the ink supply port 326 corresponding to the chamber CV[m]. That is, in this embodiment, the reservoir 325 supplies ink to the M chambers CV[1] to CV[M]. Therefore, when the ejector section D[m] is driven by the drive signal Com, the vibration accompanying the drive is propagated through the reservoir 325 to the plurality of ejector sections D, including ejector section D[m+1] and ejector section D[m-1].

[0066] 2. Overview of the Head Unit

[0067] The following is for reference Figures 5 to 8 The general outline of head unit 3 is described below.

[0068] Figure 5 This is a block diagram showing an example of the configuration of head unit 3.

[0069] like Figure 5 As shown, the head unit 3 includes a supply circuit 31, a recording head 32, and a detection circuit 33. Additionally, the head unit 3 includes a wiring Lc for supplying a drive signal Com from the drive signal generation unit 4, and a wiring Ls for supplying a detection potential signal VX[m] to the detection circuit 33.

[0070] The supply circuit 31 includes M switches Wc[1] to Wc[M] corresponding to M ejector sections D[1] to D[M], M switches Ws[1] to Ws[M] corresponding to M ejector sections D[1] to D[M], and a connection state specifying circuit 34 specifying the connection state of each switch.

[0071] The connection status specifying circuit 34 generates a connection status specifying signal Qc[m] for the on / off state of the specified switch Wc[m] and a connection status specifying signal Qs[m] for the on / off state of the specified switch Ws[m] based on the specifying signal SI, latching signal LAT, changing signal CH and period specifying signal Tsig supplied from the control unit 2.

[0072] The switch Wc[m] switches the connection between the wiring Lc and the upper electrode Zu[m] of the piezoelectric element PZ[m] to either conduction or non-conduction based on the connection state specification signal Qc[m]. In this embodiment, the switch Wc[m] is turned on when the connection state specification signal Qc[m] is high and turned off when it is low. When the switch Wc[m] is on, the drive signal Com supplied to the wiring Lc is supplied as the drive signal Vin[m] to the upper electrode Zu[m] of the ejector section D[m].

[0073] The switch Ws[m] switches the connection between the wiring Ls and the upper electrode Zu[m] of the piezoelectric element PZ[m] to be on or off based on the connection state specification signal Qs[m]. In this embodiment, the switch Ws[m] is turned on when the connection state specification signal Qs[m] is high and turned off when it is low. When the switch Ws[m] is on, a detection potential signal VX[m], indicating the potential of the upper electrode Zu[m] located on the ejector section D[m], is supplied from the upper electrode Zu[m] to the detection circuit 33 via the wiring Ls.

[0074] The detection circuit 33 generates a detection signal SK[m] with a waveform corresponding to the waveform of the detection potential signal VX[m] supplied from the wiring Ls. Specifically, the detection circuit 33 generates an amplified signal of the detection potential signal VX[m], i.e., a signal after removing noise components from the detection potential signal VX[m], and outputs the generated signal as the detection signal SK[m].

[0075] When the inkjet printer 1 performs printing processing or object determination driving processing, one or more unit periods TP are set as the operation period of the inkjet printer 1. During each unit period TP, the inkjet printer 1 can drive each ejection section D[m] for ejection section driving processing including printing processing or object determination driving processing.

[0076] Figure 6 This is a timing diagram showing an example of the various signals, such as the drive signal Com, supplied by TP to head unit 3 during a unit period.

[0077] like Figure 6 As shown, control unit 2 outputs a latch signal LAT with a pulse PLL. Therefore, control unit 2 defines the unit period TP as the period from the rise of the pulse PLL to the next rise of the pulse PLL. It should be noted that in this embodiment, the latch signal LAT is an example of a "timing signal".

[0078] In addition, the control unit 2 outputs a change signal CH with a pulse PLC during the unit period TP. Furthermore, the control unit 2 divides the unit period TP into a drive period TQ1 from the rise of the pulse PLL to the rise of the pulse PLC, and a drive period TQ2 from the rise of the pulse PLC to the rise of the pulse PLL.

[0079] Additionally, control unit 2 outputs a period-specified signal Tsig with pulses PLT1, PLT2, PLT3, and PLT4 during the unit period TP. Furthermore, control unit 2 divides the unit period TP into control periods TS1 (from the rise of pulse PLL to the rise of pulse PLT1), TS2 (from the rise of pulse PLT1 to the rise of pulse PLT2), TS3 (from the rise of pulse PLT2 to the rise of pulse PLT3), TS4 (from the rise of pulse PLT3 to the rise of pulse PLT4), and TS5 (from the rise of pulse PLT4 to the rise of pulse PLL).

[0080] like Figure 6 As shown, the specified signal SI includes M individual specified signals Sd[1] to Sd[M], each corresponding to one of the M ejector sections D[1] to D[M]. When the inkjet printer 1 performs printing processing or object determination driving processing, the individual specified signal Sd[m] specifies the driving mode of the ejector section D[m] during each unit period TP. Before each unit period TP, the control unit 2 synchronously supplies the specified signal SI, including the M individual specified signals Sd[1] to Sd[M], with the clock signal CL to the connection state specifying circuit 34. Furthermore, the connection state specifying circuit 34 generates a connection state specifying signal Qc[m] and a connection state specifying signal Qs[m] based on the individual specified signals Sd[m] during that unit period TP.

[0081] It should be noted that, in this embodiment, when the inkjet printer 1 performs printing processing or object determination driving processing, it is conceivable that the ejection section D[m] can form either a large dot composed of ink amount ξ1 or a small dot composed of ink amount ξ2 which is less than ink amount ξ1.

[0082] Figure 7 and Figure 8 This is an explanatory diagram used to illustrate a single specified signal Sd[m].

[0083] like Figure 7 and Figure 8As shown, in this embodiment, a single designated signal Sd[m] represents any one of the following values ​​during the unit period TP of performing printing processing or object determination driving processing: designating the ejector D[m] as the value "1" for the large dot forming ejector DP-1, designating the ejector D[m] as the value "2" for the small dot forming ejector DP-2, designating the ejector D[m] as the value "3" for the non-driven ejector DP-3, designating the ejector D[m] as the object determination ejector DH-1, and designating the ejector D[m] as the value "5" for the object determination ejector DH-2.

[0084] Here, the large dot-forming ejection section DP-1 is the ejection section D that forms large dots within a unit period TP. The small dot-forming ejection section DP-2 is the ejection section D that forms small dots within a unit period TP. The non-driven ejection section DP-3 is the ejection section D that is not driven by the drive signal Com within a unit period TP. The determination target ejection section DH-1 is the ejection section D that forms large dots within a unit period TP, which is the object of the ejection state determination process within a unit period TP. The determination target ejection section DH-2 is the ejection section D that forms small dots within a unit period TP, which is the object of the ejection state determination process within a unit period TP.

[0085] Return to the instructions Figure 6 .

[0086] like Figure 6 As shown, in this embodiment, the drive signal Com has a waveform PA1 set during drive period TQ1 and a waveform PA2 set during drive period TQ2.

[0087] The waveform PA1 is as follows: During the control period TS1 in the drive period TQ1, the reference potential V0 returns to the reference potential V0 via a potential VL1 that is lower than the reference potential V0 and a potential VH1 that is higher than the reference potential V0. During the control periods TS2 and TS3 in the drive period TQ1, the reference potential V0 is maintained. When the supply drive signal Vin[m] with waveform PA1 is supplied to the ejection section D[m], the waveform PA1 is determined such that ink equivalent to the ink amount ξ1 is ejected from the ejection section D[m].

[0088] Furthermore, waveform PA2 is as follows: During control period TS3 in drive period TQ2, it returns to reference potential V0 from reference potential V0 via potential VL2 (lower than reference potential V0) and potential VH2 (higher than reference potential V0). During control periods TS4 and TS5 in drive period TQ2, reference potential V0 is maintained. When a supply drive signal Vin[m] with waveform PA2 is supplied to the ejection section D[m], waveform PA2 is determined such that ink equivalent to ink amount ξ2 is ejected from the ejection section D[m].

[0089] It should be noted that, in this embodiment, as an example, it is envisioned that when the potential of the supply drive signal Vin[m] supplied to the ejection section D[m] is high, the volume of the chamber CV[m] provided by the ejection section D[m] is smaller compared to the case of a low potential. Therefore, when the ejection section D[m] is driven by the supply drive signal Vin[m] having a waveform PA1, etc., the ink in the ejection section D[m] is ejected from the nozzle N by the change in the potential of the supply drive signal Vin[m] from a low potential to a high potential.

[0090] Next, refer to Figure 7 and Figure 8 The operation of the ejector D[m], specified by a single designated signal Sd[m], is explained.

[0091] like Figure 7 As shown, when a single specified signal Sd[m] indicates that TP specifies the ejector section D[m] as the large dot forming ejector section DP-1 with a value of "1" during the unit period, the connection state specifying circuit 34 sets the connection state specifying signal Qc[m] to a high level during the driving period TQ1. In this case, the switch Wc[m] is turned on during the driving period TQ1. Therefore, the ejector section D[m] is driven by the supply drive signal Vin[m] with waveform PA1 during the unit period, ejecting ink equivalent to the ink amount ξ1 of the large dot.

[0092] Furthermore, when the single designated signal Sd[m] indicates that TP designates the ejector section D[m] as the value "2" for the small dot formation ejector section DP-2 during the unit period, the connection state designation circuit 34 sets the connection state designation signal Qc[m] to a high level during the driving period TQ2. In this case, the switch Wc[m] is turned on during the driving period TQ2. Therefore, the ejector section D[m] is driven by the supply drive signal Vin[m] with waveform PA2 during the unit period, ejecting ink equivalent to the ink amount ξ2 of the small dot.

[0093] Furthermore, when a single specified signal Sd[m] indicates that TP specifies the ejector section D[m] as the value "3" of the non-driven ejector section DP-3 during the unit period, the connection state specifying circuit 34 sets the connection state specifying signal Qc[m] and the connection state specifying signal Qs[m] to a low level for the entire unit period. In this case, switches Wc[m] and Ws[m] are disconnected by TP for the entire unit period. Therefore, the ejector section D[m] is not driven by the drive signal Com during the unit period, and no ink is ejected.

[0094] Furthermore, when a single designated signal Sd[m] indicates that the value "4" indicates that the ejector section D[m] is designated as the target ejector section DH-1 during the unit period TP, the connection state designation circuit 34 sets the connection state designation signal Qc[m] to a high level during control period TS1 and sets the connection state designation signal Qs[m] to a high level during control period TS2. In this case, switch Wc[m] is turned on during control period TS1 and switch Ws[m] is turned on during control period TS2. Therefore, the ejector section D[m] designated as the target ejector section DH-1 is driven by the supply drive signal Vin[m] with waveform PA1 during control period TS1, and as a result, the vibration generated in the ejector section D[m] remains during control period TS2. In addition, during control period TS2, the potential of the upper electrode Zu[m] provided on the ejector section D[m] changes according to the vibration remaining in the ejector section D[m]. Furthermore, during control, the detection circuit 33 detects the potential of the upper electrode Zu[m], which varies according to the vibration remaining in the ejector section D[m], as a detection potential signal VX[m] via the switch Ws[m]. That is, the waveform of the detection potential signal VX[m] detected by TS2 from the ejector section D[m] during control represents the waveform of the vibration remaining in the ejector section D[m] during control. Additionally, the waveform of the detection signal SK[m] generated based on the detection potential signal VX[m] detected by TS2 from the ejector section D[m] during control represents the waveform of the vibration remaining in the ejector section D[m] during control.

[0095] Furthermore, when a single designated signal Sd[m] indicates that the value "5" of the ejector section D[m] is designated as the target ejector section DH-2 during the unit period TP, the connection state designation circuit 34 sets the connection state designation signal Qc[m] to a high level during control period TS3 and sets the connection state designation signal Qs[m] to a high level during control period TS4. In this case, switch Wc[m] is turned on during control period TS3 and switch Ws[m] is turned on during control period TS4. Therefore, the ejector section D[m] designated as the target ejector section DH-1 is driven by the supply drive signal Vin[m] with waveform PA2 during control period TS3, and as a result, the vibration generated in the ejector section D[m] remains during control period TS4. In addition, during control period TS4, the potential of the upper electrode Zu[m] provided on the ejector section D[m] changes according to the vibration remaining in the ejector section D[m]. Furthermore, during control, the detection circuit 33 detects the potential of the upper electrode Zu[m], which varies according to the vibration remaining in the ejector section D[m], as a detection potential signal VX[m] via the switch Ws[m] during TS4. That is, the waveform of the detection potential signal VX[m] detected by TS4 from the ejector section D[m] during control represents the waveform of the vibration remaining in the ejector section D[m] during control. Additionally, the waveform of the detection signal SK[m] generated based on the detection potential signal VX[m] detected by TS4 from the ejector section D[m] during control represents the waveform of the vibration remaining in the ejector section D[m] during control.

[0096] It should be noted that, in the following, the control period TS2 for detecting residual vibration in the ejection section DH-1 of the judgment object and the control period TS4 for detecting residual vibration in the ejection section DH-2 of the judgment object will be collectively referred to as the detection period TSS.

[0097] 3. Overview of the decision-making unit

[0098] The following is for reference Figures 9 to 12 The summary of the determination unit 8 is explained below.

[0099] As described above, the determination unit 8 performs an ejection state determination process based on the detection signal SK[m] supplied from the detection circuit 33 to determine the ejection state of the ink in the ejection section D[m] designated as the ejection section DH.

[0100] Figure 9 This is an explanatory diagram illustrating an example of the detection signal SK[m] supplied by the detection circuit 33 to the determination unit 8.

[0101] like Figure 9As shown, the detection circuit 33 outputs a detection signal SK[m] during the detection period. The detection signal SK[m] represents the waveform of the vibration of the TSS remaining in the ejection section D[m] during the detection period. Specifically, the detection signal SK[m] represents the vibration that decays between the lowest potential VKL and the highest potential VKH.

[0102] In this embodiment, the determination unit 8 measures the amplitude VM[m] and the initial time TF[m] of the detection signal SK[m].

[0103] Here, the amplitude VM[m] is a value corresponding to the amplitude of the detection signal SK[m]. Specifically, in this embodiment, the amplitude VM[m] is the potential difference between the highest potential VKH and the lowest potential VKL. Additionally, the initial time TF[m] is a value corresponding to the initial phase of the detection signal SK[m]. Specifically, in this embodiment, the initial time TF[m] is the length of time from the start of the detection period TSS until the potential of the detection signal SK[m] reaches a predetermined reference potential VK0. Here, the reference potential VK0 may, for example, be the potential that forms the center of the amplitude of the detection signal SK[m].

[0104] As described above, the determination unit 8 performs ejection state determination processing based on the determination mode of the mode designation signal MS supplied from the determination management unit 23.

[0105] Figures 10 to 12 This is an explanatory diagram illustrating an example of the mode designation signal MS supplied by the determination management unit 23 to the determination unit 8.

[0106] like Figures 10 to 12 As shown, the pattern designation signal MS includes the current ejection designation signal SG[m] corresponding to the ejection part DH of the target object, the past ejection designation signal ST[m] corresponding to the ejection part DH of the target object, and the adjacent ejection designation signal SR[m] corresponding to the ejection part DH of the target object.

[0107] Figure 10 The current ejection designation signal SG[m] shown represents the same value as the single designation signal Sd[m] corresponding to the ejection section D[m] that becomes the object of ejection state determination processing.

[0108] Specifically, when the single designated signal Sd[m] indicates that the ejection part D[m] is designated as the target ejection part DH-1 with a value of "4", the current ejection designated signal SG[m] indicates a value of "4". That is, when the ejection part D[m] that becomes the target of the ejection state determination process is the target ejection part DH-1, the current ejection designated signal SG[m] indicates a value of "4".

[0109] Furthermore, when the single designated signal Sd[m] indicates that the ejection section D[m] is designated as the target ejection section DH-2 with a value of "5", the current ejection designated signal SG[m] indicates a value of "5". That is, when the ejection section D[m] that is the target of the ejection state determination process is the target ejection section DH-2, the current ejection designated signal SG[m] indicates a value of "5".

[0110] Hereinafter, the value shown by the current ejection designation signal SG[m] will be referred to as the current ejection designation value α. That is, in this embodiment, the current ejection designation value α is "4" or "5".

[0111] Figure 11 The past ejection designation signal ST[m] shown represents the same value as the single designation signal Sd[m] corresponding to the ejection section D[m] which is the object of ejection state determination processing, that is, the single designation signal Sd[m] that specifies the driving mode for the ejection section D[m] in the unit period TP before the unit period TP in which ejection state determination processing is performed on the ejection section D[m].

[0112] It should be noted that the following scenario assumes that the ejection section driving process, including printing processing and object determination driving processing, is performed in TP over K consecutive unit periods. Here, the value K is a natural number satisfying "K≥2". Furthermore, the k-th unit period TP among the K unit periods TP in which the ejection section driving process is performed will be referred to as the unit period TP(k). Here, the variable k is a natural number satisfying "1≤k≤K". In addition, the following will refer to the ejection part D[m] of the unit period TP(k) as ejection part D[m][TP(k)], the single designated signal Sd[m] of the driving mode of the ejection part D[m][TP(k)] as single designated signal Sd[m][TP(k)], the current ejection designated signal SG[m] corresponding to the ejection part D[m][TP(k)] as current ejection designated signal SG[m][TP(k)], the past ejection designated signal ST[m] corresponding to the ejection part D[m][TP(k)] as past ejection designated signal ST[m][TP(k)], and the adjacent ejection designated signal SR[m] corresponding to the ejection part D[m][TP(k)] as adjacent ejection designated signal SR[m][TP(k)].

[0113] In this case, the previously specified emission signal ST[m][TP(k)] represents the same value as the single specified signal Sd[m] that specified the driving mode of the ejector D[m] in the previous unit period TP(k-1) of unit period TP(k), that is, the single specified signal Sd[m][TP(k-1)].

[0114] Specifically, when the single designated signal Sd[m][TP(k-1)] indicates that the ejector D[m][TP(k-1)] is designated as the large dot formation ejector DP-1 with a value of "1", the past ejection designated signal ST[m][TP(k)] indicates a value of "1". That is, when the ejector D[m], which is the object of the ejection state determination process, is driven as the large dot formation ejector DP-1 in the previous unit period TP(k-1), the past ejection designated signal ST[m][TP(k)] indicates a value of "1".

[0115] Furthermore, when the single designated signal Sd[m][TP(k-1)] indicates that the ejector D[m][TP(k-1)] is designated as the small dot-forming ejector DP-2 with a value of "2", the past ejection designated signal ST[m][TP(k)] indicates a value of "2". That is, when the ejector D[m], which is the object of the ejection state determination process, is driven as the small dot-forming ejector DP-2 in the previous unit period TP(k-1), the past ejection designated signal ST[m][TP(k)] indicates a value of "2".

[0116] Furthermore, when the single designated signal Sd[m][TP(k-1)] indicates that the ejector D[m][TP(k-1)] is designated as the non-driven ejector DP-3 with a value of "3", the past ejection designated signal ST[m][TP(k)] indicates a value of "3". That is, when the ejector D[m], which is the object of the ejection state determination process, was the non-driven ejector DP-3 during the previous unit period TP(k-1), the past ejection designated signal ST[m][TP(k)] indicates a value of "3".

[0117] Hereinafter, the value represented by the past ejection specified signal ST[m][TP(k)] will be referred to as the past ejection specified value β. That is, in this embodiment, the past ejection specified value β is "1", "2" or "3".

[0118] Figure 12The adjacent ejection designation signal SR[m][TP(k)] shown represents the value of the driving mode based on one or more ejection sections D located near ejection section D[m][TP(k)]. Specifically, in this embodiment, the adjacent ejection designation signal SR[m][TP(k)] represents the value based on a single designation signal Sd[m+1][TP(k)] and a single designation signal Sd[m-1][TP(k)]. The single designation signal Sd[m+1][TP(k)] specifies the driving mode of the ejection section D[m+1][TP(k)] adjacent to ejection section D[m][TP(k)] via partition WL[m][m+1], and the single designation signal Sd[m-1][TP(k)] specifies the driving mode of the ejection section D[m-1][TP(k)] adjacent to ejection section D[m][TP(k)] via partition WL[m-1][m].

[0119] More specifically, when a single designated signal Sd[m+1][TP(k)] represents a value of "1" for the formation of ejection DP-1 at the designated large point of ejection D[m+1][TP(k)], and a single designated signal Sd[m-1][TP(k)] represents a value of "1" for the formation of ejection DP-1 at the designated large point of ejection D[m-1][TP(k)], the adjacent ejection designated signal SR[m][TP(k)] represents a value of "1".

[0120] That is, when the ejection part D[m+1] adjacent to the ejection part D[m] that is the object of ejection state determination processing is a large point forming ejection part DP-1, and the ejection part D[m-1] adjacent to the ejection part D[m] is a large point forming ejection part DP-1, the adjacent ejection designation signal SR[m][TP(k)] indicates the value "1".

[0121] Furthermore, when a single designated signal Sd[m+1][TP(k)] indicates a value of "1" for forming ejection part DP-1 at a large point specified by ejection part D[m+1][TP(k)] and a value of "2" for forming ejection part DP-2 at a small point specified by ejection part D[m-1][TP(k)], or when a single designated signal Sd[m+1][TP(k)] indicates a value of "2" for forming ejection part DP-2 at a small point specified by ejection part D[m+1][TP(k)] and a value of "1" for forming ejection part DP-1 at a large point specified by ejection part D[m-1][TP(k)], the adjacent ejection designated signal SR[m][TP(k)] indicates a value of "2".

[0122] That is, when the ejection part D[m+1] adjacent to the ejection part D[m] that is the object of the ejection state determination process is a large-dot ejection part DP-1, and the ejection part D[m-1] adjacent to the ejection part D[m] is a small-dot ejection part DP-2, the adjacent ejection designation signal SR[m][TP(k)] indicates a value of "2". Furthermore, when the ejection part D[m+1] adjacent to the ejection part D[m] that is the object of the ejection state determination process is a small-dot ejection part DP-2, and the ejection part D[m-1] adjacent to the ejection part D[m] is a large-dot ejection part DP-1, the adjacent ejection designation signal SR[m][TP(k)] indicates a value of "2".

[0123] Additionally, when a single designated signal Sd[m+1][TP(k)] indicates a value of "1" for the large point forming nozzle DP-1 of the nozzle D[m+1][TP(k)] and a single designated signal Sd[m-1][TP(k)] indicates a value of "3" for the non-driven nozzle DP-3 of the nozzle D[m-1][TP(k)], or when a single designated signal Sd[m+1][TP(k)] indicates a value of "3" for the non-driven nozzle DP-3 of the nozzle D[m+1][TP(k)] and a single designated signal Sd[m-1][TP(k)] indicates a value of "1" for the large point forming nozzle DP-1 of the nozzle D[m-1][TP(k)], the adjacent nozzle designated signal SR[m][TP(k)] indicates a value of "3".

[0124] That is, when the ejector part D[m+1] adjacent to the ejector part D[m] that is the object of the ejection state determination process is a large-point forming ejector part DP-1, and the ejector part D[m-1] adjacent to the ejector part D[m] is a non-driven ejector part DP-3, the adjacent ejection designation signal SR[m][TP(k)] indicates the value "3". Furthermore, when the ejector part D[m+1] adjacent to the ejector part D[m] that is the object of the ejection state determination process is a non-driven ejector part DP-3, and the ejector part D[m-1] adjacent to the ejector part D[m] is a large-point forming ejector part DP-1, the adjacent ejection designation signal SR[m][TP(k)] indicates the value "3".

[0125] It should be noted that in this embodiment, when the variable m is "M", that is, when there is no ejector part D[m+1], the ejector part D[m+1] is considered to be the non-driven ejector part DP-3. Furthermore, in this embodiment, when the variable m is "1", that is, when there is no ejector part D[m-1], the ejector part D[m-1] is considered to be the non-driven ejector part DP-3.

[0126] Furthermore, when a single designated signal Sd[m+1][TP(k)] represents the value "2" for forming the ejection DP-2 at the designated point of ejection D[m+1][TP(k)], and a single designated signal Sd[m-1][TP(k)] represents the value "2" for forming the ejection DP-2 at the designated point of ejection D[m-1][TP(k)], the adjacent ejection designated signal SR[m][TP(k)] represents the value "4".

[0127] That is, when the ejection part D[m+1] adjacent to the ejection part D[m] that is the object of ejection state determination processing is a small dot ejection part DP-2, and the ejection part D[m-1] adjacent to the ejection part D[m] is a small dot ejection part DP-2, the adjacent ejection designation signal SR[m][TP(k)] represents the value "4".

[0128] Additionally, when a single designated signal Sd[m+1][TP(k)] indicates a value of "2" for forming a nozzle DP-2 at a specified point in nozzle D[m+1][TP(k)], and a single designated signal Sd[m-1][TP(k)] indicates a value of "3" for forming a non-driven nozzle DP-3 at nozzle D[m-1][TP(k)], or when a single designated signal Sd[m+1][TP(k)] indicates a value of "3" for forming a non-driven nozzle DP-3 at nozzle D[m+1][TP(k)], and a single designated signal Sd[m-1][TP(k)] indicates a value of "2" for forming a nozzle DP-2 at a specified point in nozzle D[m-1][TP(k)], the adjacent nozzle designated signal SR[m][TP(k)] indicates a value of "5".

[0129] That is, when the ejection part D[m+1] adjacent to the ejection part D[m] that is the object of the ejection state determination process is a small dot ejection part DP-2, and the ejection part D[m-1] adjacent to the ejection part D[m] is a non-driven ejection part DP-3, the adjacent ejection designation signal SR[m][TP(k)] indicates a value of "5". Furthermore, when the ejection part D[m+1] adjacent to the ejection part D[m] that is the object of the ejection state determination process is a non-driven ejection part DP-3, and the ejection part D[m-1] adjacent to the ejection part D[m] is a small dot ejection part DP-2, the adjacent ejection designation signal SR[m][TP(k)] indicates a value of "5".

[0130] Furthermore, when a single designated signal Sd[m+1][TP(k)] indicates that the value of the non-driven ejector DP-3 is "3" for the ejector D[m+1][TP(k)], and a single designated signal Sd[m-1][TP(k)] indicates that the value of the non-driven ejector DP-3 is "3" for the ejector D[m-1][TP(k)], the adjacent ejector designated signal SR[m][TP(k)] indicates the value "6".

[0131] That is, when the ejection part D[m+1] adjacent to the ejection part D[m] that is the object of ejection state determination processing is a non-driven ejection part DP-3, and the ejection part D[m-1] adjacent to the ejection part D[m] is a non-driven ejection part DP-3, the adjacent ejection designation signal SR[m][TP(k)] indicates the value "6".

[0132] Hereinafter, the value represented by the adjacent ejection designation signal SR[m][TP(k)] will be referred to as the adjacent ejection designation value γ. That is, in this embodiment, the adjacent ejection designation value γ is any value from "1" to "6".

[0133] As described above, in this embodiment, the mode designation signal MS is a signal representing the current ejection designation value α, the past ejection designation value β, and the adjacent ejection designation value γ. Furthermore, the determination unit 8 performs ejection state determination processing based on the determination mode of the mode designation signal MS.

[0134] Hereinafter, the determination mode of the ejection state determination process performed on the ejection section D[m][TP(k)] will be referred to as determination mode B[m][TP(k)]. In this embodiment, determination mode B[m][TP(k)] is determined to be a combination of a current status corresponding determination mode BG selected from a plurality of current status corresponding determination modes BG, a past corresponding determination mode BT selected from a plurality of past corresponding determination modes BT, and an adjacent corresponding determination mode BR selected from a plurality of adjacent corresponding determination modes BR.

[0135] In this embodiment, the multiple current status corresponding determination modes BG include large point determination mode BG1 and small point determination mode BG2.

[0136] Here, the large point determination mode BG1 is the current status corresponding determination mode BG when the current ejection specification value α shown by the current ejection specification signal SG[m][TP(k)] is "4". That is, when the ejection part D[m][TP(k)] that becomes the object of ejection status determination processing is the determination object ejection part DH-1, the large point determination mode BG1 is selected as the current status corresponding determination mode BG.

[0137] Furthermore, the small dot determination mode BG2 is the current status corresponding determination mode BG when the current ejection specification value α shown by the current ejection specification signal SG[m][TP(k)] is "5". That is, when the ejection part D[m][TP(k)] that becomes the object of ejection status determination processing is the ejection part DH-2, the small dot determination mode BG2 is selected as the current status corresponding determination mode BG.

[0138] In addition, in this embodiment, the multiple past corresponding determination modes BT include large point determination mode BT1, small point determination mode BT2 and non-driving determination mode BT3.

[0139] Here, the large spot determination mode BT1 is the past corresponding determination mode BT when the past ejection specification value β shown by the past ejection specification signal ST[m][TP(k)] is "1". That is, when the ejection part D[m], which is the object of the ejection state determination process, is driven as the large spot forming ejection part DP-1 in the previous unit period TP(k-1), the large spot determination mode BT1 is selected as the past corresponding determination mode BT.

[0140] Furthermore, the dot determination mode BT2 is the past corresponding determination mode BT when the past ejection specification value β shown in the past ejection specification signal ST[m][TP(k)] is "2". That is, when the ejection part D[m], which is the object of the ejection state determination process, is driven as the dot-forming ejection part DP-2 in the previous unit period TP(k-1), the dot determination mode BT2 is selected as the past corresponding determination mode BT.

[0141] Furthermore, the non-drive determination mode BT3 is the past corresponding determination mode BT when the past ejection specification value β shown in the past ejection specification signal ST[m][TP(k)] is "3". That is, when the ejection part D[m], which is the object of the ejection state determination process, is the non-drive ejection part DP-3 in the previous unit period TP(k-1), the non-drive determination mode BT3 is selected as the past corresponding determination mode BT.

[0142] In addition, in this embodiment, the multiple adjacent corresponding determination modes BR include large point determination mode BR1, large point determination mode BR2, large point determination mode BR3, small point determination mode BR4, small point determination mode BR5 and non-driving determination mode BR6.

[0143] Here, the large spot determination mode BR1 is the adjacent corresponding determination mode BR when the adjacent ejection specification value γ shown by the adjacent ejection specification signal SR[m][TP(k)] is "1". That is, when ejection part D[m] is selected as the determination object ejection part DH as the object of ejection state determination processing, that is, when the ejection part D[m+1] adjacent to ejection part D[m] is a large spot forming ejection part DP-1, and the ejection part D[m-1] adjacent to ejection part D[m] is a large spot forming ejection part DP-1, the large spot determination mode BR1 is selected as the adjacent corresponding determination mode BR.

[0144] Furthermore, the large-point determination mode BR2 is the adjacent corresponding determination mode BR when the adjacent ejection specification value γ shown in the adjacent ejection specification signal SR[m][TP(k)] is "2". That is, when ejection part D[m] is selected as the determination object ejection part DH as the object of ejection state determination processing, that is, when the ejection part D[m+1] adjacent to ejection part D[m] is a large-point formed ejection part DP-1 and the ejection part D[m-1] adjacent to ejection part D[m] is a small-point formed ejection part DP-2, the large-point determination mode BR2 is selected as the adjacent corresponding determination mode BR. In addition, when the ejection part D[m] is selected as the ejection part DH to be determined as the ejection state determination process, that is, when the ejection part D[m+1] adjacent to the ejection part D[m] is a small point forming ejection part DP-2, and the ejection part D[m-1] adjacent to the ejection part D[m] is a large point forming ejection part DP-1, the large point determination mode BR2 is selected as the adjacent corresponding determination mode BR.

[0145] Furthermore, the large-point determination mode BR3 is the adjacent corresponding determination mode BR when the adjacent ejection specification value γ shown by the adjacent ejection specification signal SR[m][TP(k)] is "3". That is, when ejection part D[m] is selected as the determination object ejection part DH as the object of ejection state determination processing, that is, when the ejection part D[m+1] adjacent to ejection part D[m] is a large-point forming ejection part DP-1 and the ejection part D[m-1] adjacent to ejection part D[m] is a non-driven ejection part DP-3, the large-point determination mode BR3 is selected as the adjacent corresponding determination mode BR. In addition, when the ejection part D[m] is selected as the ejection part DH to be determined as the ejection state determination process, that is, when the ejection part D[m+1] adjacent to the ejection part D[m] is the non-driven ejection part DP-3 and the ejection part D[m-1] adjacent to the ejection part D[m] is the large point forming ejection part DP-1, the large point determination mode BR3 is selected as the adjacent corresponding determination mode BR.

[0146] Furthermore, the small dot determination mode BR4 is the adjacent corresponding determination mode BR when the adjacent ejection specification value γ shown by the adjacent ejection specification signal SR[m][TP(k)] is "4". That is, when ejection part D[m] is selected as the determination object ejection part DH as the object of ejection state determination processing, that is, when the ejection part D[m+1] adjacent to ejection part D[m] is a small dot ejection part DP-2, and the ejection part D[m-1] adjacent to ejection part D[m] is a small dot ejection part DP-2, the small dot determination mode BR4 is selected as the adjacent corresponding determination mode BR.

[0147] Furthermore, the small dot determination mode BR5 is the adjacent corresponding determination mode BR when the adjacent ejection specification value γ shown in the adjacent ejection specification signal SR[m][TP(k)] is "5". That is, when ejection part D[m] is selected as the determination object ejection part DH as the object of ejection state determination processing, that is, when the ejection part D[m+1] adjacent to ejection part D[m] is a small dot forming ejection part DP-2 and the ejection part D[m-1] adjacent to ejection part D[m] is a non-driven ejection part DP-3, the small dot determination mode BR5 is selected as the adjacent corresponding determination mode BR. In addition, when the ejection part D[m] is selected as the ejection part DH to be determined as the ejection state determination process, that is, when the ejection part D[m+1] adjacent to the ejection part D[m] is the non-driven ejection part DP-3 and the ejection part D[m-1] adjacent to the ejection part D[m] is the small dot formation ejection part DP-2, the small dot determination mode BR5 is selected as the adjacent corresponding determination mode BR.

[0148] Furthermore, the non-driving determination mode BR6 is the adjacent corresponding determination mode BR when the adjacent ejection specification value γ shown by the adjacent ejection specification signal SR[m][TP(k)] is "6". That is, when ejection part D[m] is selected as the determination object ejection part DH as the object of ejection state determination processing, that is, when the ejection part D[m+1] adjacent to ejection part D[m] is a non-driving ejection part DP-3 and the ejection part D[m-1] adjacent to ejection part D[m] is a non-driving ejection part DP-3, the non-driving determination mode BR6 is selected as the adjacent corresponding determination mode BR.

[0149] In the present embodiment, in the ejection state determination process for the ejection unit D[m][TP(k)], when the amplitude determination condition that the amplitude VM[m] is not less than the threshold value VM-L(α,β,γ) and not more than the threshold value VM-H(α,β,γ) is satisfied, and the phase determination condition that the initial time TF[m] is not less than the threshold value TF-L(α,β,γ) and not more than the threshold value TF-H(α,β,γ) is satisfied, the determination unit 8 generates determination information SH[m] indicating that the ejection state in the ejection unit D[m][TP(k)] is normal. On the other hand, when the amplitude VM[m] does not satisfy the amplitude determination condition or the initial time TF[m] does not satisfy the phase determination condition, the determination unit 8 generates determination information SH[m] indicating that the ejection state in the ejection unit D[m][TP(k)] is abnormal.

[0150] It should be noted that the threshold values VM-L(α,β,γ) and VM-H(α,β,γ) are real numbers satisfying "0 < VM-L(α,β,γ) < VM-H(α,β,γ)", and the threshold values TF-L(α,β,γ) and TF-H(α,β,γ) are real numbers satisfying "0 < TF-L(α,β,γ) < TF-H(α,β,γ)".

[0151] Here, the thresholds VM-L(α,β,γ), VM-H(α,β,γ), TF-L(α,β,γ), and TF-H(α,β,γ) used in the ejection state determination process targeting the ejection section D[m][TP(k)] are determined based on the determination mode B[m][TP(k)] involved in the ejection state determination process. That is, in this embodiment, the thresholds VM-L(α,β,γ), VM-H(α,β,γ), TF-L(α,β,γ), and TF-H(α,β,γ) used in the ejection state determination process targeting the ejection section D[m][TP(k)] are determined based on the current status corresponding determination mode BG selected in the ejection state determination process, the past corresponding determination mode BT selected in the ejection state determination process, and the adjacent corresponding determination mode BR selected in the ejection state determination process. In other words, in this embodiment, the thresholds VM-L(α,β,γ), VM-H(α,β,γ), TF-L(α,β,γ), and TF-H(α,β,γ) used in the ejection state determination process targeting the ejection section D[m][TP(k)] are determined based on the current ejection specified value α shown by the current ejection specified signal SG[m][TP(k)], the past ejection specified value β shown by the past ejection specified signal ST[m][TP(k)], and the adjacent ejection specified value γ shown by the adjacent ejection specified signal SR[m][TP(k)]. It should be noted that, hereinafter, the thresholds VM-L(α,β,γ), VM-H(α,β,γ), TF-L(α,β,γ), and TF-H(α,β,γ) are collectively referred to as "determination thresholds".

[0152] It should be noted that when the ejector section D[m+1] is driven as either the large-dot-forming ejector section DP-1 or the small-dot-forming ejector section DP-2, so-called "crosstalk" occurs, which causes pressure fluctuations associated with this drive to affect the ejector section D[m] via the partition WL[m][m+1] and the storage unit 325. Therefore, when the ejector section D[m+1] is driven as either the large-dot-forming ejector section DP-1 or the small-dot-forming ejector section DP-2, compared to the case where it is not driven, the amplitude VM[m] of the detection signal SK[m] based on the detection potential signal VX[m] detected from the ejector section D[m] increases, and the initial time TF[m] of the detection signal SK[m] based on the detection potential signal VX[m] detected from the ejector section D[m] decreases. The same applies when the ejector section D[m-1] is driven as either the large-dot-forming ejector section DP-1 or the small-dot-forming ejector section DP-2.

[0153] Therefore, in this embodiment, in the ejection state determination process targeting the ejection part D[m], a determination threshold is determined such that when the ejection part D near the ejection part D[m] is driven, compared with the case where the ejection part D near the ejection part D[m] is not driven, the thresholds VM-L(α,β,γ) and VM-H(α,β,γ) are increased, and the thresholds TF-L(α,β,γ) and TF-H(α,β,γ) are decreased.

[0154] Specifically, in this embodiment, a decision threshold is determined such that, in the case of small-dot decision mode BR5, compared to the case of non-driven decision mode BR6, the thresholds VM-L(α,β,γ) and VM-H(α,β,γ) are increased, and the thresholds TF-L(α,β,γ) and TF-H(α,β,γ) are decreased. Furthermore, in this embodiment, a decision threshold is determined such that, in the case of small-dot decision mode BR4, compared to the case of small-dot decision mode BR5, the thresholds VM-L(α,β,γ) and VM-H(α,β,γ) are increased, and the thresholds TF-L(α,β,γ) and TF-H(α,β,γ) are decreased. Additionally, in this embodiment, a decision threshold is determined such that, in the case of large-dot decision mode BR2, compared to the case of small-dot decision mode BR4, the thresholds VM-L(α,β,γ) and VM-H(α,β,γ) are increased, and the thresholds TF-L(α,β,γ) and TF-H(α,β,γ) are decreased. Furthermore, in this embodiment, a decision threshold is determined such that, in the case of large-point decision mode BR2, compared with the case of large-point decision mode BR3, the thresholds VM-L(α,β,γ) and VM-H(α,β,γ) are increased, and the thresholds TF-L(α,β,γ) and TF-H(α,β,γ) are decreased. Additionally, in this embodiment, a decision threshold is determined such that, in the case of large-point decision mode BR1, compared with the case of large-point decision mode BR2, the thresholds VM-L(α,β,γ) and VM-H(α,β,γ) are increased, and the thresholds TF-L(α,β,γ) and TF-H(α,β,γ) are decreased.

[0155] It should be noted that when the size of point Dt formed by ejector D[m] is the same as the size of point Dt formed by ejector D[m+1], compared to the case where they are different sizes, the impact of pressure fluctuations driven by ejector D[m+1] on ejector D[m] is greater. Therefore, in the ejection state determination process targeting ejector D[m], a determination threshold is determined such that when the size of point Dt formed by ejector D[m] is the same as the size of point Dt formed by ejector D[m+1], compared to the case where they are different sizes, the thresholds VM-L(α,β,γ) and VM-H(α,β,γ) are increased, and the thresholds TF-L(α,β,γ) and TF-H(α,β,γ) are decreased.

[0156] Specifically, in the ejection state determination process with the ejection part D[m] as the object, that is, in the ejection state determination process where the current corresponding determination mode BG is the large point determination mode BG1, a determination threshold can also be determined so that when the adjacent corresponding determination mode BR is the large point determination mode BR1, compared with the case of the small point determination mode BR4, the threshold VM-L(α,β,γ) and the threshold VM-H(α,β,γ) become larger, and the threshold TF-L(α,β,γ) and the threshold TF-H(α,β,γ) become smaller. In addition, in the ejection state determination process with the ejection part D[m] as the object, that is, in the ejection state determination process when the current corresponding determination mode BG is the large point determination mode BG1, a determination threshold can be determined so that when the adjacent corresponding determination mode BR is the large point determination mode BR3, compared with the small point determination mode BR5, the thresholds VM-L(α,β,γ) and VM-H(α,β,γ) become larger, and the thresholds TF-L(α,β,γ) and TF-H(α,β,γ) become smaller. In addition, in the ejection state determination process with the ejection part D[m] as the object, that is, in the ejection state determination process when the current corresponding determination mode BG is the small point determination mode BG2, a determination threshold can be determined so that when the adjacent corresponding determination mode BR is the small point determination mode BR4, compared with the case of the large point determination mode BR1, the threshold VM-L(α,β,γ) and the threshold VM-H(α,β,γ) become larger, and the threshold TF-L(α,β,γ) and the threshold TF-H(α,β,γ) become smaller. In addition, in the ejection state determination process with the ejection part D[m] as the object, that is, in the ejection state determination process when the current corresponding determination mode BG is the small point determination mode BG2, a determination threshold can be determined so that when the adjacent corresponding determination mode BR is the small point determination mode BR5, compared with the case of the large point determination mode BR3, the threshold VM-L(α,β,γ) and the threshold VM-H(α,β,γ) become larger, and the threshold TF-L(α,β,γ) and the threshold TF-H(α,β,γ) become smaller.

[0157] 4. Generation of specified signals by the control unit

[0158] The following is for reference Figures 13 to 16 The generation of the specified signal SI by the ejection control unit 22 provided in the control unit 2 will be described. It should be noted that, hereinafter, the process of generating the specified signal SI will be referred to as the specified signal generation process.

[0159] Figure 13 This is a flowchart illustrating an example of the operation of control unit 2 when performing a specified signal generation process.

[0160] like Figure 13 As shown, in the specified signal generation process, firstly, the ejection control unit 22 sets the variable k to "1" (S101).

[0161] Next, the ejection control unit 22 generates a printing designation signal SI0[TP(k)] (S103) based on the printing data Img, which includes a single printing designation signal Sd0[1][TP(k)] to Sd0[M][TP(k)]. Here, the printing designation signal SI0[TP(k)] is a signal that specifies the driving mode of the unit period TP(k) of the M ejection sections D[1] to D[M] of the head unit 3 required to form the image shown in the printing data Img on the recording paper PP, assuming that the ejection state determination process and the determination object driving process are not performed.

[0162] Furthermore, the single print designation signal Sd0[m][TP(k)] specifies the driving mode of the ejector section D[m] per unit period TP(k) required to form the image shown in the print data Img on the recording paper PP, assuming that the ejection state determination process and the determination object driving process are not performed. Specifically, the single print designation signal Sd0[m][TP(k)] represents any one of the following three values ​​in the unit period TP(k): designating the ejector section D[m][TP(k)] as a large dot forming ejector section DP-1 (value "1"), designating the ejector section D[m][TP(k)] as a small dot forming ejector section DP-2 (value "2"), and designating the ejector section D[m][TP(k)] as a non-driven ejector section DP-3 (value "3").

[0163] Next, the ejection control unit 22 determines whether the value k is "k = K" (S105).

[0164] Furthermore, if the determination result of the ejection control unit 22 in step S105 is negative, it adds "1" to the value k (S107) and then proceeds to step S103. If the determination result of the ejection control unit 22 in step S105 is positive, it sets the value k to "1" (S109).

[0165] Next, the ejection control unit 22 selects one or more candidate ejection units DK from ejection units D[1][TP(k)] to D[M][TP(k)] (S111). Here, the candidate ejection unit DK is an ejection unit D from ejection units D[1][TP(k)] to D[M][TP(k)] that can become the ejection unit DH to be determined. In this embodiment, when a single printing designation signal Sd0[m][TP(k)] designates ejection unit D[m][TP(k)] as a large dot formation ejection unit DP-1, this ejection unit D[m][TP(k)] can become the ejection unit DH-1 to be determined. In addition, in this embodiment, when a single printing designation signal Sd0[m][TP(k)] designates ejection unit D[m][TP(k)] as a small dot formation ejection unit DP-2, this ejection unit D[m][TP(k)] can become the ejection unit DH-2 to be determined. That is, in this embodiment, the candidate ejector DK is determined to be the ejector D[m][TP(k)] of ejector D[1][TP(k)] to D[M][TP(k)], which is designated as the large dot forming ejector DP-1 by a single printing designation signal Sd0[m][TP(k)], and the ejector D[m][TP(k)] of ejector DP-2, which is designated as the small dot forming ejector DP-2 by a single printing designation signal Sd0[m][TP(k)].

[0166] Next, the ejection control unit 22 selects a target ejection unit DH from one or more candidate ejection units DK selected in step S111 (S113).

[0167] Specifically, in step S113, the ejection control unit 22 selects one or more candidate ejection units DK that is capable of ejection state determination processing based on large point determination mode BG1 as the ejection unit D[m] for determination, rather than ejection unit D[m] that is capable of ejection state determination processing based on small point determination mode BG2 as the ejection unit DH.

[0168] Here, the ejector section D[m] capable of performing ejection state determination processing based on the large dot determination mode BG1 refers to the ejector section D[m][TP(k)] designated by a single printing designation signal Sd0[m][TP(k)] as the large dot forming ejector section DP-1. Conversely, the ejector section D[m] capable of performing ejection state determination processing based on the small dot determination mode BG2 refers to the ejector section D[m][TP(k)] designated by a single printing designation signal Sd0[m][TP(k)] as the small dot forming ejector section DP-2.

[0169] In addition, in step S113, the ejection control unit 22 selects one or more candidate ejection units DK that can perform ejection state determination processing based on non-drive determination mode BT3, prioritizing ejection units D[m] that can perform ejection state determination processing based on small dot determination mode BT2. Furthermore, the ejection unit D[m] that can perform ejection state determination processing based on small dot determination mode BT2 is selected as the ejection unit DH to be determined.

[0170] Here, the ejector section D[m] capable of performing ejection state determination processing based on the large dot determination mode BT1 refers to the ejector section D[m] whose single print designation signal Sd0[m][TP(k-1)] is designated as the large dot forming ejector section DP-1 during the unit period TP(k-1) preceding the execution of the ejection state determination processing targeting the ejector section D[m][TP(k)]. Similarly, the ejector section D[m] capable of performing ejection state determination processing based on the small dot determination mode BT2 refers to the ejector section D[m] whose single print designation signal Sd0[m][TP(k-1)] is designated as the small dot forming ejector section DP-2 during the unit period TP(k-1) preceding the execution of the ejection state determination processing targeting the ejector section D[m][TP(k)]. In addition, the ejection section D[m] that can perform ejection state determination processing based on non-drive determination mode BT3 refers to the ejection section D[m] that is designated as non-drive ejection section DP-3 by a single printing designation signal Sd0[m][TP(k-1)] in the unit period TP(k-1) before the execution of ejection state determination processing targeting ejection section D[m][TP(k-1)].

[0171] Furthermore, in step S113, the ejection control unit 22 selects one or more candidate ejection units DK from which ejection units D[m] capable of performing ejection state determination processing based on the non-drive determination mode BR6 are preferred over ejection units D[m] capable of performing ejection state determination processing based on the small dot determination mode BR5; selects ejection units D[m] capable of performing ejection state determination processing based on the small dot determination mode BR5 are preferred over ejection units D[m] capable of performing ejection state determination processing based on the small dot determination mode BR4; and selects ejection units D[m] capable of performing ejection state determination processing based on the small dot determination mode BR5 are preferred over ejection units capable of performing ejection state determination processing based on the large dot determination mode BR3. The ejector section D[m] that is subject to the determination process is selected as the ejector section DH that is capable of ejection state determination processing based on the small point determination mode BR4, rather than the ejector section D[m] that is capable of ejection state determination processing based on the large point determination mode BR2. The ejector section D[m] that is capable of ejection state determination processing based on the large point determination mode BR3 is selected as the ejector section D[m] that is capable of ejection state determination processing based on the large point determination mode BR2. In addition, the ejector section D[m] that is capable of ejection state determination processing based on the large point determination mode BR2 is selected as the ejector section D[m] that is capable of ejection state determination processing based on the large point determination mode BR1 is selected as the ejector section DH that is subject to the determination process.

[0172] Here, the ejection section D[m] that can perform ejection state determination processing based on the large dot determination mode BR1 refers to the ejection section D[m+1] adjacent to the ejection section D[m] that is designated as the large dot forming ejection section DP-1 by a single printing designation signal Sd0[m+1], and the ejection section D[m-1] adjacent to the ejection section D[m] that is designated as the large dot forming ejection section DP-1 by a single printing designation signal Sd0[m-1].

[0173] In addition, the ejection section D[m] capable of performing ejection state determination processing based on the large dot determination mode BR2 refers to the ejection section D[m+1] adjacent to the ejection section D[m] being designated as a large dot forming ejection section DP-1 by a single printing designation signal Sd0[m+1], and the ejection section D[m-1] adjacent to the ejection section D[m] being designated as a small dot forming ejection section DP-2 by a single printing designation signal Sd0[m-1], or the ejection section D[m+1] adjacent to the ejection section D[m] being designated as a small dot forming ejection section DP-2 by a single printing designation signal Sd0[m+1], and the ejection section D[m-1] adjacent to the ejection section D[m] being designated as a large dot forming ejection section DP-1 by a single printing designation signal Sd0[m-1].

[0174] In addition, the ejection section D[m] capable of performing ejection state determination processing based on the large dot determination mode BR3 refers to the ejection section D[m+1] adjacent to the ejection section D[m] being designated as the large dot forming ejection section DP-1 by a single printing designation signal Sd0[m+1], and the ejection section D[m-1] adjacent to the ejection section D[m] being designated as the non-driven ejection section DP-3 by a single printing designation signal Sd0[m-1], or the ejection section D[m+1] adjacent to the ejection section D[m] being designated as the non-driven ejection section DP-3 by a single printing designation signal Sd0[m+1], and the ejection section D[m-1] adjacent to the ejection section D[m] being designated as the large dot forming ejection section DP-1 by a single printing designation signal Sd0[m-1].

[0175] In addition, the ejection section D[m] that can perform ejection state determination processing based on the small dot determination mode BR4 refers to the ejection section D[m+1] adjacent to the ejection section D[m] being designated as the small dot forming ejection section DP-2 by a single printing designation signal Sd0[m+1], and the ejection section D[m-1] adjacent to the ejection section D[m] being designated as the small dot forming ejection section DP-2 by a single printing designation signal Sd0[m-1].

[0176] In addition, the ejection section D[m] that can perform ejection state determination processing based on the small dot determination mode BR5 refers to the ejection section D[m+1] adjacent to the ejection section D[m] being designated as the small dot forming ejection section DP-2 by a single printing designation signal Sd0[m+1], and the ejection section D[m-1] adjacent to the ejection section D[m] being designated as the non-driven ejection section DP-3 by a single printing designation signal Sd0[m-1], or the ejection section D[m+1] adjacent to the ejection section D[m] being designated as the non-driven ejection section DP-3 by a single printing designation signal Sd0[m+1], and the ejection section D[m-1] adjacent to the ejection section D[m] being designated as the small dot forming ejection section DP-2 by a single printing designation signal Sd0[m-1].

[0177] In addition, the ejection section D[m] that can perform ejection state determination processing based on non-drive determination mode BR6 refers to the ejection section D[m+1] adjacent to the ejection section D[m] that is designated as non-drive ejection section DP-3 by a single printing designation signal Sd0[m+1], and the ejection section D[m-1] adjacent to the ejection section D[m] that is designated as non-drive ejection section DP-3 by a single printing designation signal Sd0[m-1].

[0178] Next, based on the selection result of the target ejection unit DH in step S113, the ejection control unit 22 updates the printing designation signal SI0[TP(k)] generated in step S103, thereby generating a designation signal SI[TP(k)] including a single designation signal Sd[1][TP(k)] to Sd[M][TP(k)] (S115).

[0179] Next, the ejection control unit 22 determines whether the value k is "k = K" (S117).

[0180] Furthermore, if the determination result of the ejection control unit 22 in step S117 is negative, it adds "1" to the value k (S119) and then proceeds to step S111. On the other hand, if the determination result of the ejection control unit 22 in step S117 is positive, it ends the process. Figure 13 The specified signal generation process is shown.

[0181] Figures 14 to 16 This is an explanatory diagram illustrating an example of printed specified signal SI0 and specified signal SI generated in a specified signal generation process. It should be noted that... Figures 14 to 16 In this case, as an example, we assume that the value M is "6", that is, the head unit 3 has ejection sections D[1] to D[6]. Additionally, in Figures 14 to 16 In this case, as an example, we assume that the value K is “6”, that is, the ejection section driving process, which includes printing processing and object determination driving processing, is performed during the unit period TP(1) to TP(6).

[0182] First, in step S103, as Figure 14 As shown, the ejection control unit 22 generates a printing designation signal SI0[TP(k)] for each unit period TP(k), including individual printing designation signals Sd0[1][TP(k)] to Sd0[M][TP(k)]. Here, the label Ap1 indicates that the individual printing designation signal Sd0[m][TP(k)] designates a large dot to form the ejection section DP-1. Additionally, the label Ap2 indicates that the individual printing designation signal Sd0[m][TP(k)] designates a small dot to form the ejection section DP-2. It should be noted that when the individual printing designation signal Sd0[m][TP(k)] is not labeled with Ap1 or Ap2, it indicates that the individual printing designation signal Sd0[m][TP(k)] designates a non-driven ejection section DP-3.

[0183] Next, in step S111, as follows Figure 15As shown, the ejection control unit 22 selects the ejection unit D[m][TP(k)] corresponding to a single printing designation signal Sd0[m][TP(k)] marked with label Ap1 or label Ap2 as the candidate ejection unit DK. Here, label AK indicates that a single printing designation signal Sd0[m][TP(k)] corresponds to the ejection unit D[m][TP(k)] selected as the candidate ejection unit DK.

[0184] Then, in steps S113 and S115, as follows Figure 16 As shown, the ejection control unit 22 generates a designated signal SI[TP(k)] comprising a single designated signal Sd[1][TP(k)] to Sd[M][TP(k)] for each unit period TP(k) by selecting a target ejection unit DH from one or more candidate ejection units DK and updating the printing designated signal SI0 based on the selection result. Here, the marker AH indicates that the ejection unit D[m][TP(k)] corresponding to the single designated signal Sd[m][TP(k)] is selected as the target ejection unit DH.

[0185] It should be noted that, in Figure 16 In the diagram, a single designated signal Sd[m][TP(k)] marked with AH and Ap1 designates the ejection section D[m][TP(k)] as the target ejection section DH-1. Additionally, a single designated signal Sd[m][TP(k)] marked with AH and Ap2 designates the ejection section D[m][TP(k)] as the target ejection section DH-2. Furthermore, a single designated signal Sd[m][TP(k)] marked with AK and Ap1 designates the ejection section D[m][TP(k)] as the large-dot ejection section DP-1. Finally, a single designated signal Sd[m][TP(k)] marked with AK and Ap2 designates the ejection section D[m][TP(k)] as the small-dot ejection section DP-2. In addition, the single designated signal Sd[m][TP(k)], which is not marked AH, AK, Ap1, or Ap2, designates the non-driven ejector DP-3 for the ejector D[m][TP(k)].

[0186] It should be noted that when there are unit periods TP(k1) and TP(k2) within the unit periods TP(1) to TP(K), the ejection control unit 22 selects the ejection target ejection unit H from one or more candidate ejection units DK, so that the ejection state determination processing of the unit period TP(k2) takes precedence over the ejection state determination processing of the unit period TP(k1). Specifically, in the unit period TP(k1), ejection state determination processing based on the determination mode of setting the past corresponding determination mode BT to large point determination mode BT1 or small point determination mode BT2, with the ejection unit D[m] as the target, can be performed. In the unit period TP(k2), ejection state determination processing based on the determination mode of setting the past corresponding determination mode BT to non-driving determination mode BT3, with the ejection unit D[m] as the target, can be performed. Here, variable k1 is a natural number satisfying "1≤k1≤K", and variable k2 is a natural number satisfying "1≤k2≤K" and "k2≠k1".

[0187] Furthermore, when there are unit periods TP(k1) and unit periods TP(k2) in the unit periods TP(1) to TP(K), the ejection control unit 22 selects the ejection target ejection unit H from one or more candidate ejection units DK, so that the ejection state determination processing of unit period TP(k2) takes precedence over the ejection state determination processing of unit period TP(k1). In this unit period TP(k1), ejection state determination processing based on a determination mode other than the non-driving determination mode BR6 can be performed on the ejection unit D[m]. In this unit period TP(k2), ejection state determination processing based on the determination mode of the non-driving determination mode BR6 can be performed on the ejection unit D[m].

[0188] 5. Summary of Implementation Methods

[0189] As described above, the inkjet printer 1 according to this embodiment is characterized by comprising: an ejection section D[m], a piezoelectric element PZ[m] driven by a drive signal Com during a unit period TP(k) defined by a latching signal LAT, a chamber CV[m] filled with ink and whose volume changes according to the drive of the piezoelectric element PZ[m], and a nozzle N[m] that ejects ink from the chamber CV[m] according to the change in the volume of the chamber CV[m]; a detection circuit 33 that detects the potential of the piezoelectric element PZ[m]; and a determination unit 8 that determines the ejection state of the ink in the ejection section D[m] based on the detection result of the detection circuit 33 by a determination mode selected from a plurality of determination modes, wherein the determination unit 8 determines the case where the piezoelectric element PZ[m] is driven by the drive signal Com during a unit period TP(k-1) prior to the unit period TP(k). The ink ejection state in the ejection section D[m] is determined based on the detection signal SK[m], which represents the detection result of the detection circuit 33 representing the unit period TP(k), by using the determination mode B[m][TP(k)], which includes the large dot determination mode BT1 as the past corresponding determination mode BT, or the determination mode B[m][TP(k)], which includes the small dot determination mode BT2 as the past corresponding determination mode BT. If the piezoelectric element PZ[m] is not driven by the drive signal Com during the unit period TP(k) before the unit period TP(k), the ink ejection state in the ejection section D[m] is determined based on the detection signal SK[m], which represents the detection result of the detection circuit 33 representing the unit period TP(k), by using the determination mode B[m][TP(k)], which includes the non-drive determination mode BT3 as the past corresponding determination mode BT.

[0190] In this embodiment, the ejection state determination process is performed by selecting a determination mode based on whether or not the ejection section D[m] is driven during a unit period TP(k-1). Therefore, according to this embodiment, the influence of the drive of the ejection section D[m] during a unit period TP(k-1) on the ejection section D[m] during a unit period TP(k) can be taken into account, and ejection state determination process targeting the ejection section D[m] can be performed during a unit period TP(k). That is, according to this embodiment, compared to a method that performs ejection state determination process targeting the ejection section D[m] during a unit period TP(k) without considering the drive of the ejection section D[m] during a unit period TP(k-1), the ejection state determination process can accurately determine the ejection state of the ink in the ejection section D[m].

[0191] It should be noted that in this embodiment, the unit period TP(k) is an example of "one unit period", and the unit period TP(k-1) is an example of "other unit periods". Furthermore, hereinafter, the decision pattern B[m][TP(k)] including the large point decision pattern BT1 and the decision pattern B[m][TP(k)] including the small point decision pattern BT2 are sometimes collectively referred to as the past driving decision pattern BT-K, and the decision pattern B[m][TP(k)] including the non-driving decision pattern BT3 is collectively referred to as the past non-driving decision pattern BT-H. Here, the past driving decision pattern BT-K is an example of the "first decision pattern", and the past non-driving decision pattern BT-H is an example of the "second decision pattern".

[0192] Furthermore, in this embodiment, the determination unit 8 selects determination mode B[m][TP(k)] from multiple determination modes based on a single specified signal Sd[m][TP(k)] indicating whether the piezoelectric element PZ[m] is driven by the drive signal Com during the unit period TP(k), and determines the ink ejection state in the ejection section D[m] based on determination mode B[m][TP(k)] using the detection signal SK[m] representing the detection result of the detection circuit 33 during the unit period TP(k).

[0193] Therefore, according to this embodiment, compared with the method of performing ejection state determination processing for ejection section D[m] in unit period TP(k) without considering the driving of ejection section D[m], the ejection state determination processing can accurately determine the ejection state of ink in ejection section D[m].

[0194] It should be noted that in this embodiment, a single designated signal Sd[m][TP(k)] is an example of "a designated signal".

[0195] Furthermore, in this embodiment, the determination unit 8 selects determination mode B[m][TP(k)] from multiple determination modes based on a single specified signal Sd[m][TP(k-1)] indicating whether the piezoelectric element PZ[m] is driven by the drive signal Com during the unit period TP(k-1), and determines the ink ejection state in the ejection section D[m] based on determination mode B[m][TP(k)] using the detection signal SK[m] representing the detection result of the detection circuit 33 during the unit period TP(k).

[0196] Therefore, according to this embodiment, compared with the method of performing ejection state determination processing for ejection section D[m] in unit period TP(k) without considering the driving of ejection section D[m] in unit period TP(k-1), the ejection state determination processing can accurately determine the ejection state of ink in ejection section D[m].

[0197] It should be noted that in this embodiment, a single designated signal Sd[m][TP(k-1)] is an example of "other designated signals".

[0198] In addition, this embodiment may also be characterized by having an ejection control unit 22 that controls the ejection section D[m] by a specified signal SI, wherein the specified signal SI specifies whether there is a drive signal Com for the piezoelectric element PZ[m] in a unit period TP. When there are unit periods TP(k1) and unit periods TP(k2) in the K unit periods TP(1) to TP(K) specified by the latch signal LAT, the ejection control unit 22 prioritizes the ejection state determination process of unit period TP(k2) over the ejection state determination process of unit period TP(k1). In this unit period TP(k1), the ejection state determination process targeting the ejection section D[m] can be performed by the past drive determination mode BT-K, and in this unit period TP(k2), the ejection state determination process targeting the ejection section D[m] can be performed by the past non-drive determination mode BT-H.

[0199] Therefore, according to this embodiment, when the ejection state determination process targeting the ejection part D[m] is performed in a unit period TP(k), the possibility that the drive of the ejection part D[m] in a unit period TP(k-1) will affect the ejection state determination process can be reduced.

[0200] It should be noted that in this embodiment, the unit period TP(k1) is an example of the "first unit period", and the unit period TP(k2) is an example of the "second unit period".

[0201] It should be noted that, in the following, the four thresholds used in the ejection state determination process based on the past driving determination mode BT-K—VM-L(α,β,γ), VM-H(α,β,γ), TF-L(α,β,γ), and TF-H(α,β,γ)—are respectively referred to as past driving threshold VM-L11, past driving threshold VM-H11, past driving threshold TF-L11, and past driving threshold TF-H11. Furthermore, the four thresholds used in the ejection state determination process based on the past non-driving determination mode BT-H—VM-L(α,β,γ), VM-H(α,β,γ), TF-L(α,β,γ), and TF-H(α,β,γ)—are respectively referred to as past non-driving threshold VM-L12, past non-driving threshold VM-H12, past non-driving threshold TF-L12, and past non-driving threshold TF-H12.

[0202] In this embodiment, when the determination unit 8 performs ejection state determination processing for the ejection section D[m] using the past drive determination mode BT-K, it compares the amplitude VM[m] of the detection signal SK[m] representing the detection result of the detection circuit 33 for a unit period TP(k) with the past drive threshold VM-L11 and the past drive threshold VM-H11, and compares the initial time TF[m] of the detection signal SK[m] representing the detection result of the detection circuit 33 for a unit period TP(k) with the past drive threshold TF-L11 and the past drive threshold TF-H11, and determines the ejection state of the ink in the ejection section D[m] based on the two comparison results. In addition, in this embodiment, when the determination unit 8 performs the ejection state determination process for the ejection section D[m] using the past non-driving determination mode BT-H, it compares the amplitude VM[m] of the detection signal SK[m] representing the detection result of the detection circuit 33 representing the unit period TP(k) with the past non-driving threshold VM-L12 and the past non-driving threshold VM-H12, and compares the initial time TF[m] of the detection signal SK[m] representing the detection result of the detection circuit 33 representing the unit period TP(k) with the past non-driving threshold TF-L12 and the past non-driving threshold TF-H12, and determines the ejection state of the ink in the ejection section D[m] based on the comparison result. Here, the past driving threshold VM-L11 and the past non-driving threshold VM-L12 are different from each other, the past driving threshold VM-H11 and the past non-driving threshold VM-H12 are different from each other, the past driving threshold TF-L11 and the past non-driving threshold TF-L12 are different from each other, and the past driving threshold TF-H11 and the past non-driving threshold TF-H12 are different from each other.

[0203] Therefore, according to this embodiment, compared with the method of using the same determination threshold for driving the ejection section D[m] regardless of whether there is a unit period TP(k-1), the ejection state of the ink in the ejection section D[m] can be accurately determined in the ejection state determination process.

[0204] It should be noted that, in this embodiment, the past driving threshold VM-L11, past driving threshold VM-H11, past driving threshold TF-L11, and past driving threshold TF-H11 are examples of the "first determination benchmark value", and the past non-driving threshold VM-L12, past non-driving threshold VM-H12, past non-driving threshold TF-L12, and past non-driving threshold TF-H12 are examples of the "second determination benchmark value".

[0205] It should be noted that, in the following, the decision pattern B[m][TP(k)] including the large point decision pattern BR1, the decision pattern B[m][TP(k)] including the large point decision pattern BR2, the decision pattern B[m][TP(k)] including the large point decision pattern BR3, the decision pattern B[m][TP(k)] including the small point decision pattern BR4, and the decision pattern B[m][TP(k)] including the small point decision pattern BR5 are sometimes collectively referred to as the adjacent driving decision pattern BR-K, and the decision pattern B[m][TP(k)] including the non-driving decision pattern BR6 is collectively referred to as the adjacent non-driving decision pattern BR-H. Here, the adjacent driving decision pattern BR-K is another example of the "first decision pattern", and the adjacent non-driving decision pattern BR-H is another example of the "second decision pattern".

[0206] In this embodiment, the inkjet printer 1 is characterized by comprising: M ejection sections D[1] to D[m], including ejection section D[m] and ejection section D[m+1]. The ejection section D[m] comprises a piezoelectric element PZ[m] activated by a drive signal Com, a chamber CV[m] filled with ink and whose volume changes according to the drive of the piezoelectric element PZ[m], and a nozzle N[m] ejecting ink from the chamber CV[m] according to the change in volume of the chamber CV[m]. The ejection section D[m+1] comprises a piezoelectric element PZ[m+1] activated by a drive signal Com, a chamber CV[m+1] filled with ink and whose volume changes according to the drive of the piezoelectric element PZ[m+1], and a nozzle N[m] ejecting ink from the chamber CV[m+1] according to the change in volume of the chamber CV[m+1]. The device includes a nozzle N[m+1]; a storage unit 325 that supplies ink to M ejector sections D[1] to D[M]; a detection circuit 33 that detects the potential of a piezoelectric element PZ[m]; and a determination unit 8 that determines the ejection state of the ink in the ejector section D[m] based on the detection result of the detection circuit 33 by selecting a determination mode from a plurality of determination modes. When the ejector section D[m+1] is driven by the drive signal Com, the determination unit 8 determines the ejection state of the ink in the ejector section D[m] by the adjacent drive determination mode BR-K according to the detection signal SK[m] representing the detection result of the detection circuit 33. When the ejector section D[m+1] is not driven by the drive signal Com, the determination unit 8 determines the ejection state of the ink in the ejector section D[m] by the adjacent non-drive determination mode BR-H according to the detection signal SK[m] representing the detection result of the detection circuit 33.

[0207] Thus, according to this embodiment, the ejection state determination process targeting the ejection section D[m] can be performed by taking into account the influence of the driving of the ejection section D[m+1] on the ejection section D[m]. That is, according to this embodiment, compared with the method of performing ejection state determination process targeting the ejection section D[m] without considering the driving of the ejection section D[m+1], the ejection state determination process can accurately determine the ejection state of the ink in the ejection section D[m].

[0208] It should be noted that in this embodiment, the ejector part D[m] is an example of a "first ejector part", the ejector part D[m+1] is an example of a "second ejector part", the piezoelectric element PZ[m] is an example of a "first piezoelectric element", the piezoelectric element PZ[m+1] is an example of a "second piezoelectric element", the chamber CV[m] is an example of a "first pressure chamber", the chamber CV[m+1] is an example of a "second pressure chamber", the nozzle N[m] is an example of a "first nozzle", and the nozzle N[m+1] is an example of a "second nozzle".

[0209] In addition, in this embodiment, the chamber CV[m] disposed in the ejection section D[m] and the chamber CV[m+1] disposed in the ejection section D[m+1] are adjacent to each other via a partition WL[m][m+1].

[0210] In this case, the vibration generated in the ejector section D[m+1] due to the driving of the ejector section D[m+1] is transmitted to the ejector section D[m] via the partition WL[m][m+1]. In contrast, in this embodiment, the ejection state determination process for the ejector section D[m] is performed considering the driving of the ejector section D[m+1]. Therefore, according to this embodiment, compared to the method of performing the ejection state determination process for the ejector section D[m] without considering the driving of the ejector section D[m+1], the ejection state determination process can accurately determine the ejection state of the ink in the ejector section D[m].

[0211] Furthermore, in this embodiment, the determination unit 8 selects from multiple determination modes the determination mode used in the ejection state determination process for the ejection section D[m] based on a single specified signal Sd[m] that specifies whether or not the piezoelectric element PZ[m] is driven by the drive signal Com.

[0212] Therefore, according to this embodiment, the ejection state determination process for the ejection section D[m] can be performed by taking into account the influence of the driving of the ejection section D[m] on the ejection state determination process for the ejection section D[m]. That is, according to this embodiment, compared with the method of performing the ejection state determination process for the ejection section D[m] without considering the influence of the driving of the ejection section D[m] on the ejection state determination process for the ejection section D[m], the ejection state of the ink in the ejection section D[m] can be accurately determined in the ejection state determination process.

[0213] It should be noted that in this embodiment, a single designated signal Sd[m] is an example of a "first designated signal".

[0214] Furthermore, in this embodiment, the determination unit 8 selects from multiple determination modes the determination mode used in the ejection state determination process targeting the ejection section D[m] based on a single specified signal Sd[m+1] that specifies whether or not the piezoelectric element PZ[m+1] is driven by the drive signal Com.

[0215] Therefore, according to this embodiment, the ejection state determination process for the ejection section D[m] can be performed by taking into account the influence of the driving of the ejection section D[m+1] on the ejection state determination process for the ejection section D[m]. That is, according to this embodiment, compared with the method of performing the ejection state determination process for the ejection section D[m] without considering the influence of the driving of the ejection section D[m+1] on the ejection state determination process for the ejection section D[m], the ejection state of the ink in the ejection section D[m] can be accurately determined in the ejection state determination process.

[0216] It should be noted that in this embodiment, a single designated signal Sd[m+1] is an example of a "second designated signal".

[0217] In addition, in this embodiment, it may also be characterized by having an ejection control unit 22 that controls M ejection sections D[1] to D[M] by a specified signal SI[TP(k)]. The specified signal SI[TP(k)] specifies whether the M ejection sections D[1] to D[M] are driven by the drive signal Com during the K unit periods TP(1) to TP(K) specified by the latch signal LAT. When there are unit periods TP(k1) and unit periods TP(k2) in the K unit periods TP(1) to TP(K), the ejection control unit 22 prioritizes the ejection state determination process of unit period TP(k2) over the ejection state determination process of unit period TP(k1). In this unit period TP(k1), the ejection state determination process targeting ejection section D[m] can be performed through the adjacent drive determination mode BR-K, and in this unit period TP(k2), the ejection state determination process targeting ejection section D[m] can be performed through the adjacent non-drive determination mode BR-H.

[0218] Therefore, according to this embodiment, when performing ejection state determination processing targeting ejection section D[m], the possibility of the drive of ejection section D[m+1] affecting the ejection state determination processing can be reduced.

[0219] It should be noted that, in the following, the four thresholds used in the ejection state determination process based on the adjacent drive determination mode BR-K—VM-L(α,β,γ), VM-H(α,β,γ), TF-L(α,β,γ), and TF-H(α,β,γ)—are respectively referred to as adjacent drive threshold VM-L21, adjacent drive threshold VM-H21, adjacent drive threshold TF-L21, and adjacent drive threshold TF-H21. Furthermore, the four thresholds used in the ejection state determination process based on the adjacent non-drive determination mode BR-H—VM-L(α,β,γ), VM-H(α,β,γ), TF-L(α,β,γ), and TF-H(α,β,γ)—are respectively referred to as adjacent non-drive threshold VM-L22, adjacent non-drive threshold VM-H22, adjacent non-drive threshold TF-L22, and adjacent non-drive threshold TF-H22.

[0220] In this embodiment, when the determination unit 8 performs ejection state determination processing for the ejection section D[m] using the adjacent drive determination mode BR-K, it compares the amplitude VM[m] of the detection signal SK[m] representing the detection result of the detection circuit 33 for a unit period TP(k) with the adjacent drive threshold VM-L21 and the adjacent drive threshold VM-H21, and compares the initial time TF[m] of the detection signal SK[m] representing the detection result of the detection circuit 33 for a unit period TP(k) with the adjacent drive threshold TF-L21 and the adjacent drive threshold TF-H21, and determines the ejection state of the ink in the ejection section D[m] based on the two comparison results. In addition, in this embodiment, when the determination unit 8 performs ejection state determination processing for the ejection section D[m] through the adjacent non-driving determination mode BR-H, it compares the amplitude VM[m] of the detection signal SK[m] representing the detection result of the detection circuit 33 representing the unit period TP(k) with the adjacent non-driving threshold VM-L22 and the adjacent non-driving threshold VM-H22, and compares the initial time TF[m] of the detection signal SK[m] representing the detection result of the detection circuit 33 representing the unit period TP(k) with the adjacent non-driving threshold TF-L22 and the adjacent non-driving threshold TF-H22, and determines the ejection state of the ink in the ejection section D[m] based on the two comparison results. Here, the adjacent driving threshold VM-L21 and the adjacent non-driving threshold VM-L22 are different from each other, the adjacent driving threshold VM-H21 and the adjacent non-driving threshold VM-H22 are different from each other, the adjacent driving threshold TF-L21 and the adjacent non-driving threshold TF-L22 are different from each other, and the adjacent driving threshold TF-H21 and the adjacent non-driving threshold TF-H22 are different from each other.

[0221] Therefore, according to this embodiment, compared with the method of using the same determination threshold regardless of whether there is an ejection section D[m+1], the ejection state of the ink in the ejection section D[m] can be accurately determined in the ejection state determination process.

[0222] It should be noted that, in this embodiment, the adjacent driving threshold VM-L21, adjacent driving threshold VM-H21, adjacent driving threshold TF-L21, and adjacent driving threshold TF-H21 are other examples of the "first determination benchmark value", and the adjacent non-driving threshold VM-L22, adjacent non-driving threshold VM-H22, adjacent non-driving threshold TF-L22, and adjacent non-driving threshold TF-H22 are other examples of the "second determination benchmark value".

[0223] B. Variations

[0224] The above methods can be modified in various ways. Specific modifications are illustrated below. Any two or more methods selected from the following examples can be appropriately combined within the scope of non-contradiction. It should be noted that in the following examples of modifications, elements with the same function and implementation method are represented by the same symbols used in the above description, and their detailed descriptions are appropriately omitted.

[0225] Variation Example 1

[0226] In the above embodiment, the method described is to generate K specified signals SI[TP(1)] to SI[TP(k)] corresponding to K unit periods TP(1) to TP(K) after generating and executing K unit period drive processes corresponding to K printing specified signals SI0[TP(1)] to SI0[TP(K)], but the present invention is not limited to this method. For example, the ejection control unit 22 may also generate specified signals SI[TP(k)] whenever printing specified signals SI0[TP(k)] corresponding to unit period TP(k) are generated.

[0227] Figure 17 This is a flowchart illustrating an example of the operation of the control unit 2 when performing the specified signal generation process involved in this variation.

[0228] like Figure 17 As shown, in the specified signal generation process involved in this modified example, firstly, the ejection control unit 22 sets the variable k to "1" (S101).

[0229] Next, the ejection control unit 22 generates a printing designation signal SI0[TP(k)] based on the printing data Img, which includes a single printing designation signal Sd0[1][TP(k)] to Sd0[M][TP(k)] (S103). Then, the ejection control unit 22 selects one or more candidate ejection units DK from the ejection units D[1][TP(k)] to D[M][TP(k)] (S111).

[0230] Next, the ejection control unit 22 selects a target ejection unit DH from one or more candidate ejection units DK selected in step S111 (S113).

[0231] Next, based on the selection result of the target ejection unit DH in step S113, the ejection control unit 22 updates the printing designation signal SI0[TP(k)] generated in step S103, thereby generating a designation signal SI[TP(k)] including a single designation signal Sd[1][TP(k)] to Sd[M][TP(k)] (S115).

[0232] Next, the ejection control unit 22 determines whether the value k is "k = K" (S117).

[0233] Furthermore, if the determination result of the ejection control unit 22 in step S117 is negative, it adds "1" to the value k (S119) and then proceeds to step S111. On the other hand, if the determination result of the ejection control unit 22 in step S117 is positive, it ends the process. Figure 17 The specified signal generation process is shown.

[0234] It should be noted that, in this modified example, the ejection control unit 22 may also select the ejection part DH to be determined based on some or all of the k specified signals SI[TP(1)] to SI[TP(k)] corresponding to the unit periods TP(1) to TP(k) in step S113. In this case, when the ejection state determination process targeting the ejection part D[m] is performed in the unit period TP(k), the possibility that the drive of the ejection part D[m] in the unit period TP(k-1) will affect the ejection state determination process can be reduced. In addition, in this case, when the ejection state determination process targeting the ejection part D[m] is performed, the possibility that the drive of the ejection part D[m+1] will affect the ejection state determination process can be reduced.

[0235] Variation Example 2

[0236] In the above-described embodiments and variations 1, when the determination unit 8 performs ejection state determination processing with the ejection part D[m] as the object, it selects the adjacent corresponding determination mode BR based on the driving mode of the ejection part D[m+1] and the ejection part D[m-1] adjacent to the ejection part D[m]. However, the present invention is not limited to such a method.

[0237] For example, when the determination unit 8 performs ejection state determination processing with ejection part D[m] as the object, it may select the adjacent corresponding determination mode BR based not only on the driving mode of ejection part D[m+1] and ejection part D[m-1] adjacent to ejection part D[m], but also on the driving mode of ejection part D[m+2] adjacent to ejection part D[m+1] and ejection part D[m-2] adjacent to ejection part D[m-1].

[0238] In addition, for example, when the determination unit 8 performs ejection state determination processing for ejection section D[m], it may also select the adjacent corresponding determination mode BR based on the driving mode of ejection section D which is different from that of ejection section D[m].

[0239] That is, in this modified example, when the determination unit 8 performs the ejection state determination process for the ejection part D[m], it can also select the determination mode B[m][TP(k)] based on the driving mode or the presence or absence of driving of multiple ejection parts D located within a specified range including the ejection part D[m].

[0240] According to this modified example, when vibrations generated in a specific ejector D, which are driven by a different ejector D than the ejector D[m], are transmitted to the ejector D[m] via the storage 325, the ejection state determination process targeting the ejector D[m] can be performed, taking into account the vibrations transmitted from the specific ejector D to the ejector D[m]. Therefore, according to this embodiment, compared to the method of performing ejection state determination process targeting the ejector D[m] without considering the drive of the specific ejector D, the ejection state of the ink in the ejector D[m] can be accurately determined in the ejection state determination process.

[0241] Variation Example 3

[0242] In the above embodiments and variations 1 and 2, the determination unit 8 performs ejection state determination processing for the ejection part D[m] based on the amplitude VM[m] and the initial time TF[m] of the detection signal SK[m]. However, the present invention is not limited to such a method.

[0243] For example, the determination unit 8 may also perform ejection state determination processing for the ejection section D[m] based on either the amplitude VM[m] of the detection signal SK[m] or the initial time TF[m]. Specifically, in the ejection state determination processing for the ejection section D[m], the determination unit 8 may also generate determination information SH[m] indicating that the ejection state of the ejection section D[m] is normal if the amplitude VM[m] is above the threshold VM-L(α,β,γ) and below the threshold VM-H(α,β,γ). Furthermore, in the ejection state determination processing for the ejection section D[m], the determination unit 8 may also generate determination information SH[m] indicating that the ejection state of the ejection section D[m] is normal if the initial time TF[m] is above the threshold TF-L(α,β,γ) and below the threshold TF-H(α,β,γ).

[0244] Variation Example 4

[0245] In the above embodiments and variations 1 to 3, the determination mode when the determination unit 8 performs the ejection state determination process is described as a combination of the current status corresponding determination mode BG, the past corresponding determination mode BT, and the adjacent corresponding determination mode BR. However, the present invention is not limited to this approach. The determination mode when the determination unit 8 performs the ejection state determination process only needs to include at least one of the past corresponding determination mode BT and the adjacent corresponding determination mode BR. Specifically, the determination unit 8 may also perform the ejection state determination process using one of the multiple past corresponding determination modes BT. In addition, the determination unit 8 may also perform the ejection state determination process using one of the multiple adjacent corresponding determination modes BR.

[0246] Variation Example 5

[0247] In the above embodiments and variations 1 to 4, the head unit 3 is configured to include a supply circuit 31, a recording head 32, and a detection circuit 33, but the present invention is not limited to this configuration. The head unit 3 may also be configured to include components other than the supply circuit 31, the recording head 32, and the detection circuit 33. For example, in addition to the supply circuit 31, the recording head 32, and the detection circuit 33, the head unit 3 may also include a determination unit 8.

[0248] Figure 18 This is a functional block diagram illustrating an example of the configuration of the inkjet printer 1B involved in this variation.

[0249] like Figure 18 As shown, the inkjet printer 1B includes a control unit 2B, a head unit 3B, a drive signal generation unit 4, and a transport unit 7.

[0250] Control unit 2B differs from control unit 2 in that it does not have a spray control unit 22 and a determination management unit 23.

[0251] Head unit 3B differs from head unit 3 in that it includes ejection control unit 22, determination management unit 23 and determination unit 8.

[0252] According to this modified example, since the head unit 3B has an ejection control unit 22, a determination management unit 23 and a determination unit 8, when developing a new inkjet printer, by applying the head unit 3B to the inkjet printer, ejection status determination processing can be easily performed.

[0253] Variation Example 6

[0254] In the above embodiments and variations 1 to 5, it is envisioned that the inkjet printer 1 has four head units 3, but the present invention is not limited to this configuration. The inkjet printer 1 may have one or more but no more than three head units 3, and it may also have five or more head units 3.

[0255] Modification Example 7

[0256] In the above embodiments and variations 1 to 6, the inkjet printer 1 is illustrated as a serial printer, but the present invention is not limited to this type. The inkjet printer 1 can also be a so-called line printer in which multiple nozzles N in the head unit 3 are arranged in a manner that extends wider than the width of the recording paper PP.

Claims

1. A liquid ejection device, characterized in that, have: Multiple ejection sections, including a first ejection section and a second ejection section, wherein the first ejection section includes a first piezoelectric element driven by a drive signal, a first pressure chamber filled with liquid and whose volume changes according to the drive of the first piezoelectric element, and a first nozzle ejecting the liquid in the first pressure chamber according to the change in volume of the first pressure chamber; the second ejection section includes a second piezoelectric element driven by the drive signal, a second pressure chamber filled with liquid and whose volume changes according to the drive of the second piezoelectric element, and a second nozzle ejecting the liquid in the second pressure chamber according to the change in volume of the second pressure chamber. A common liquid chamber supplies liquid to the plurality of ejector sections; The detection unit detects the potential of the first piezoelectric element; as well as The determination unit determines the ejection state of the first ejection unit based on the detection result of the detection unit, using a determination mode selected from multiple determination modes including a first determination mode and a second determination mode. When the determination unit is driven by the driving signal to drive the second piezoelectric element, Based on the detection results from the detection unit, the ejection state in the first ejection unit is determined using the first determination mode. In the absence of the second piezoelectric element being driven by the drive signal Based on the detection results of the detection unit, the ejection state in the first ejection unit is determined by the second determination mode.

2. The liquid ejection device according to claim 1, characterized in that, The first pressure chamber located in the first ejection section and the second pressure chamber located in the second ejection section are adjacent to each other via a partition.

3. The liquid ejection device according to claim 1, characterized in that, The determination unit is based on a specific designated signal that specifies the presence or absence of a plurality of specific ejector sections located within a predetermined range including the first ejector section and the second ejector section, as indicated by the drive signal. Select the determination mode used in determining the ejection state in the first ejection section from the plurality of determination modes.

4. The liquid ejection device according to claim 1, characterized in that, The determination unit is based on a first specified signal that indicates the presence or absence of the first piezoelectric element being driven, as specified by the driving signal. Select the determination mode used in determining the ejection state in the first ejection section from the plurality of determination modes.

5. The liquid ejection device according to claim 1, characterized in that, The determination unit is based on a second specified signal that specifies the presence or absence of the second piezoelectric element driven by the drive signal. Select the determination mode used in determining the ejection state in the first ejection section from the plurality of determination modes.

6. The liquid ejection device according to claim 1, characterized in that, The system includes an ejection control unit that controls the ejection of the plurality of ejector sections via a specified signal, wherein the specified signal specifies the presence or absence of drive of each of the plurality of ejector sections during a unit period defined by a timing signal. The ejection control unit exists during multiple unit periods specified by the timing signal. The first unit period during which the ejection state in the first ejection section can be determined by the first determination mode, and In the case where the second determination mode is used to determine the ejection state in the first ejection section during the second unit period, The determination based on the second determination mode takes precedence over the determination based on the first determination mode.

7. The liquid ejection device according to claim 1, characterized in that, The determination unit is in the first determination mode. The characteristic quantity of the detection signal representing the detection result of the detection unit is compared with a first determination reference value to obtain a comparison result, and the ejection state in the first ejection unit is determined based on the comparison result. In the second determination mode, The characteristic quantity of the detection signal representing the detection result of the detection unit is compared with a second determination benchmark value that is different from the first determination benchmark value to obtain a comparison result, and the ejection state in the first ejection unit is determined based on the comparison result.

8. A printhead, characterized in that, have: Multiple ejector sections, including a first ejector section and a second ejector section. The first ejection section includes a first piezoelectric element driven by a drive signal, a first pressure chamber filled with liquid whose volume changes according to the drive of the first piezoelectric element, and a first nozzle that ejects the liquid from the first pressure chamber according to the change in volume of the first pressure chamber. The second ejection section includes a second piezoelectric element driven by the drive signal, a second pressure chamber filled with liquid and whose volume changes according to the drive of the second piezoelectric element, and a second nozzle that ejects the liquid in the second pressure chamber according to the change in the volume of the second pressure chamber. A common liquid chamber supplies liquid to the plurality of ejector sections; The detection unit detects the potential of the first piezoelectric element; as well as The determination unit determines the ejection state of the first ejection unit based on the detection result of the detection unit, using a determination mode selected from multiple determination modes including a first determination mode and a second determination mode. When the determination unit is driven by the driving signal to drive the second piezoelectric element, Based on the detection results from the detection unit, the ejection state in the first ejection unit is determined using the first determination mode. In the absence of the second piezoelectric element being driven by the drive signal Based on the detection results of the detection unit, the ejection state in the first ejection unit is determined by the second determination mode.

9. The printhead according to claim 8, characterized in that, The first pressure chamber located in the first ejection section, and The second pressure chambers located in the second ejection section are adjacent to each other via partitions.

10. The printhead according to claim 8, characterized in that, The determination unit is based on a specific designated signal that specifies the presence or absence of a plurality of specific ejector sections located within a predetermined range including the first ejector section and the second ejector section, as indicated by the drive signal. Select the determination mode used in determining the ejection state in the first ejection section from the plurality of determination modes.

11. The printhead according to claim 8, characterized in that, The determination unit is based on a first specified signal that indicates the presence or absence of the first piezoelectric element being driven, as specified by the driving signal. Select the determination mode used in determining the ejection state in the first ejection section from the plurality of determination modes.

12. The printhead according to claim 8, characterized in that, The determination unit is based on a second specified signal that specifies the presence or absence of the second piezoelectric element driven by the drive signal. Select the determination mode used in determining the ejection state in the first ejection section from the plurality of determination modes.

13. The printhead according to claim 8, characterized in that, The system includes an ejection control unit that controls the ejection of the plurality of ejector sections via a specified signal, wherein the specified signal specifies the presence or absence of drive of each of the plurality of ejector sections during a unit period defined by a timing signal. The determination unit exists during multiple unit periods defined by the timing signal. The first unit period during which the ejection state in the first ejection section can be determined by the first determination mode, and In the case where the second determination mode is used to determine the ejection state in the first ejection section during the second unit period, The determination based on the second determination mode takes precedence over the determination based on the first determination mode.

14. The printhead according to claim 8, characterized in that, The determination unit is in the first determination mode. The characteristic quantity of the detection signal representing the detection result of the detection unit is compared with a first determination reference value to obtain a comparison result, and the ejection state in the first ejection unit is determined based on the comparison result. In the second determination mode, The characteristic quantity of the detection signal representing the detection result of the detection unit is compared with a second determination benchmark value that is different from the first determination benchmark value to obtain a comparison result, and the ejection state in the first ejection unit is determined based on the comparison result.

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