Liquid discharge device, control method of liquid discharge device, and control program of liquid discharge device

Abstract

To properly and easily determine a waveform of a driving signal for driving a piezoelectric element.SOLUTION: A liquid discharge device 100 comprises a liquid discharge head 1 and a waveform specifying part 40. The liquid discharge head 1 has: a nozzle N; a piezoelectric element PZ that is supplied with a driving signal COMa to be driven; a vibration plate 14 that is vibrated by driving the piezoelectric element PZ; a pressure chamber CV which is filled with ink and to which pressure for making the nozzle N discharge ink is applied by vibration of the vibration plate 14; and a detection circuit 19 that detects residual vibrations of the vibration plate 14 after the piezoelectric element PZ is driven. The waveform specifying part 40 specifies a natural vibration period Tc of the pressure chamber CV, on the basis of the residual vibrations detected by the detection circuit 19; and obtains, from a storing unit 5, waveform information showing a correspondent relation between the natural vibration period Tc and a waveform of the driving signal COMa; and determines the waveform of the driving signal COMa that is supplied to the piezoelectric element PZ, on the basis of the natural vibration period Tc specified based on the residual vibrations and the waveform information.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection apparatus, a control method for a liquid ejection apparatus, and a control program for a liquid ejection apparatus. [Background technology]

[0002] Liquid ejection devices are known that print images by ejecting liquid, such as ink, from nozzles using piezoelectric elements. For example, a liquid ejection device includes a liquid ejection head that ejects liquid from a pressure chamber through a nozzle by vibrating a vibration plate that constitutes part of the pressure chamber using a piezoelectric element. The natural vibration period of the pressure chamber is determined by the shape of the pressure chamber and varies from liquid ejection head to liquid ejection head due to assembly accuracy and dimensional accuracy of components during liquid ejection head manufacturing. Variations in the natural vibration period of the pressure chamber cause variations in the liquid ejection characteristics. For this reason, for example, in a printhead manufacturing method disclosed in Patent Document 1, the natural vibration period of each assembled printhead is measured and the printhead is classified into one of several ranks based on the measured natural vibration period. The rank of the natural vibration period associated with the printhead is used, for example, to determine the waveform of a drive signal that drives the piezoelectric element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-351703 Summary of the Invention [Problem to be solved by the invention]

[0004] The natural vibration period of a pressure chamber varies not only due to manufacturing variations in the liquid ejection head, but also depending on the operating conditions of the liquid ejection head. For example, the natural vibration period of a pressure chamber varies depending on ink conditions, such as the type of ink. Consider a business model in which a head manufacturer that manufactures liquid ejection heads sells the liquid ejection heads to printing device manufacturers, who then assemble the liquid ejection devices. In this business model, the operating conditions of the liquid ejection head, such as ink conditions, are often determined by the printing device manufacturer, not the head manufacturer. If the head manufacturer also assembles the liquid ejection device, the head manufacturer also determines the operating conditions, allowing the natural vibration period to be determined. In contrast, in the above-described business model, there is a risk that the head manufacturer will not be able to properly determine the natural vibration period when it manufactures and sells the liquid ejection head. In such a case, it is difficult for the head manufacturer to determine an appropriate drive signal waveform based on the natural vibration period. Therefore, in the above-described business model, the printing device manufacturer must determine an appropriate drive signal waveform based on the natural vibration period, which could place an excessive burden on the printing device manufacturer. For this reason, in the above-mentioned business model, it is desirable to be able to appropriately and easily determine the waveform of the drive signal that drives the piezoelectric element. Incidentally, even if the manufacturer of the liquid ejection device and the manufacturer of the liquid ejection head share the same business model, it is desirable, albeit to a relatively small extent. It is conceivable that a user may independently set usage conditions that differ from those previously assumed by the manufacturer of the liquid ejection head or liquid ejection device, and in such cases, similar problems arise. [Means for solving the problem]

[0005] In order to solve the above problems, the liquid ejection device of the present invention comprises a liquid ejection head and a control unit, wherein the liquid ejection head has a nozzle, a piezoelectric element that is driven by a drive signal supplied thereto, a vibration plate that vibrates when the piezoelectric element is driven, a pressure chamber that is filled with liquid and to which pressure for ejecting liquid from the nozzle is applied by the vibration of the vibration plate, and a detection unit that detects residual vibration of the vibration plate after the piezoelectric element is driven, and the control unit identifies the natural vibration period of the pressure chamber based on the residual vibration detected by the detection unit, acquires waveform information from a memory unit that indicates the correspondence between the natural vibration period and the waveform of the drive signal, and determines the waveform of the drive signal to be supplied to the piezoelectric element based on the natural vibration period identified based on the residual vibration and the waveform information acquired from the memory unit.

[0006] In addition, a control method for a liquid ejection device according to the present invention is a control method for a liquid ejection device equipped with a liquid ejection head including a nozzle, a piezoelectric element that is driven by the supply of a drive signal, a vibration plate that vibrates when the piezoelectric element is driven, a pressure chamber that is filled with liquid and to which pressure for ejecting liquid from the nozzle is applied by the vibration of the vibration plate, and a detection unit that detects residual vibration of the vibration plate after the piezoelectric element is driven, wherein the natural vibration period of the pressure chamber is identified based on the residual vibration detected by the detection unit, waveform information indicating the correspondence between the natural vibration period and the waveform of the drive signal is obtained from a memory unit, and the waveform of the drive signal to be supplied to the piezoelectric element is determined based on the natural vibration period identified based on the residual vibration and the waveform information obtained from the memory unit.

[0007] In addition, the control program for a liquid ejection device according to the present invention is a control program for a liquid ejection device equipped with a liquid ejection head including a nozzle, a piezoelectric element that is driven by a drive signal supplied thereto, a vibration plate that vibrates when the piezoelectric element is driven, a pressure chamber that is filled with liquid and to which pressure for ejecting liquid from the nozzle is applied by the vibration of the vibration plate, and a detection unit that detects residual vibration of the vibration plate after the piezoelectric element is driven, and causes a computer to function as a control unit that identifies the natural vibration period of the pressure chamber based on the residual vibration detected by the detection unit, acquires waveform information from a memory unit that indicates the correspondence between the natural vibration period and the waveform of the drive signal, and determines the waveform of the drive signal to be supplied to the piezoelectric element based on the natural vibration period identified based on the residual vibration and the waveform information acquired from the memory unit. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing an example of a configuration of a liquid ejection apparatus according to an embodiment of the present invention. [Figure 2] FIG. 1 is a configuration diagram schematically illustrating a liquid ejection device. [Figure 3] FIG. 2 is an exploded perspective view of the liquid ejection head. [Figure 4] FIG. 4 is a cross-sectional view taken along the line III-III shown in FIG. [Figure 5] FIG. 2 is a block diagram showing an example of the configuration of a liquid ejection head. [Figure 6] 10 is a timing chart showing an example of an operation of the liquid ejection device in a unit period. [Figure 7] FIG. 10 is a diagram showing an example of a waveform of a residual vibration signal. [Figure 8] 10A and 10B are explanatory diagrams for explaining correction information that is referred to when determining the waveform of a drive signal. [Figure 9] 10 is a flowchart showing an example of the operation of the liquid ejection device when determining the waveform of a drive signal. [Figure 10] FIG. 10 is a diagram showing an example of a waveform of a residual vibration signal according to a first modified example. [Figure 11]FIG. 10 is an explanatory diagram for explaining correction information according to a first modified example. [Figure 12] 10 is a flowchart showing an example of the operation of the liquid ejection device according to the first modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, in each drawing, the dimensions and scale of each part are appropriately different from those of the actual parts. Furthermore, since the embodiments described below are preferred examples of the present invention, various technically preferable limitations are applied, but the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description to the effect that the present invention is limited.

[0010] [1. Embodiment] First, an overview of a liquid ejection device 100 according to this embodiment will be described with reference to Fig. 1. In this embodiment, a case will be taken as an example in which the liquid ejection device 100 is an inkjet printer that forms an image by ejecting ink onto a medium PP. In this embodiment, the medium PP will be assumed to be recording paper shown in Fig. 2, which will be described later.

[0011] FIG. 1 is a block diagram showing an example of the configuration of a liquid ejection device 100 according to an embodiment of the present invention.

[0012] Print data IMG indicating an image to be formed by the liquid ejection device 100 is supplied from a host computer such as a personal computer or a digital camera to the liquid ejection device 100. The liquid ejection device 100 executes a printing process to form, on a medium PP, an image indicated by the print data IMG supplied from the host computer.

[0013] The liquid ejection device 100 includes a liquid ejection head 1 having an ejection section D including nozzles N that eject ink, a drive signal generation unit 2 that generates multiple drive signals COM for driving the ejection section D, and an analysis unit 3 that analyzes residual vibrations (described later). The nozzles N will be described later with reference to FIGS. 3 and 4. The liquid ejection device 100 also includes a control unit 4 that controls each section of the liquid ejection device 100, and a storage unit 5 that stores various information such as print data IMG and a control program PG for the liquid ejection device 100. The liquid ejection device 100 also includes a maintenance unit 7 that performs maintenance processing for the liquid ejection head 1, a medium transport mechanism 8 that transports a medium PP, a carriage transport mechanism 9 that reciprocates a carriage 91, and an ink container 60 that stores ink. The carriage 91 will be described later with reference to FIG. 2. The control unit 4 is an example of a "computer," and the ink is an example of a "liquid."

[0014] In this embodiment, it is assumed that the liquid ejection head 1 and the drive signal generation unit 2 correspond to each other, and that the liquid ejection head 1 and the analysis unit 3 correspond to each other. For example, the liquid ejection device 100 may have a plurality of liquid ejection heads 1, a plurality of drive signal generation units 2, and a plurality of analysis units 3. In this case, for example, the plurality of drive signal generation units 2 correspond to the plurality of liquid ejection heads 1 one-to-one, and the plurality of analysis units 3 correspond to the plurality of liquid ejection heads 1 one-to-one. Alternatively, the liquid ejection device 100 may have one liquid ejection head 1, one drive signal generation unit 2 corresponding to the liquid ejection head 1, and one analysis unit 3 corresponding to the liquid ejection head 1.

[0015] In this embodiment, it is assumed that the liquid ejection device 100 has four liquid ejection heads 1 corresponding to four types of ink: cyan, magenta, yellow, and black. That is, in this embodiment, it is assumed that the liquid ejection device 100 has four liquid ejection heads 1, four drive signal generation units 2, and four analysis units 3. However, for convenience of explanation, the following description may focus on one of the four liquid ejection heads 1 and one drive signal generation unit 2 corresponding to that one liquid ejection head 1, as exemplified in FIG.

[0016] First, before describing the liquid ejection head 1, the control unit 4, the drive signal generating unit 2, and the storage unit 5 will be described.

[0017] The control unit 4 is configured to include one or more CPUs (Central Processing Units). Note that the control unit 4 may be configured to include a programmable logic device such as an FPGA (field-programmable gate array) instead of or in addition to a CPU. Furthermore, for example, the control unit 4 operates in accordance with a control program PG stored in the storage unit 5 to generate signals for controlling the operation of each part of the liquid ejection device 100, such as a print signal SI and a waveform designation signal dCOM. For example, the waveform designation signal dCOM is generated by a waveform definition unit 40, which will be described later.

[0018] Here, the waveform designation signal dCOM is a digital signal that defines the waveform of each of the multiple drive signals COM. Furthermore, each drive signal COM is an analog signal for driving a discharge section D. In this embodiment, as shown in FIG. 5 (to be described later), it is assumed that the multiple drive signals COM include drive signals COMa and COMb. Furthermore, the print signal SI is a digital signal for designating the type of operation of the discharge section D. Specifically, the print signal SI is a signal that designates whether or not to supply each drive signal COM to the discharge section D, thereby designating the type of operation of the discharge section D.

[0019] In this embodiment, the control unit 4 functions as a waveform defining section 40 by operating in accordance with the control program PG stored in the storage unit 5. Details of the operation of the waveform defining section 40 will be explained in Figures 8 and 9, but for example, the waveform defining section 40 determines the waveform of the drive signal COMa based on the natural vibration period Tc of the pressure chamber CV that communicates with the nozzle N. The pressure chamber CV will be described later with reference to Figures 3 and 4.

[0020] The drive signal generation unit 2 includes, for example, a DAC (Digital Analog Converter), and generates a plurality of drive signals COM based on a waveform designation signal dCOM supplied from the control unit 4. For example, each of the plurality of drive signals COM generated by the drive signal generation unit 2 includes a waveform defined by the waveform designation signal dCOM. The drive signal generation unit 2 outputs the plurality of drive signals COM generated based on the waveform designation signal dCOM to a switching circuit 18 included in the liquid ejection head 1.

[0021] The storage unit 5 includes one or both of a volatile memory such as a RAM (Random Access Memory) and a non-volatile memory such as a ROM (Read Only Memory), an EEPROM (Electrically Erasable Programmable Read-Only Memory), or a PROM (Programmable ROM). The storage unit 5 may be included in the control unit 4.

[0022] In this embodiment, the storage unit 5 stores, in addition to the control program PG, correction information Cinf that is referenced when determining the waveform of the drive signal COMa. Details will be explained in FIG. 8, but the correction information Cinf indicates the correspondence between the natural vibration period Tc of the pressure chamber CV and the waveform of the drive signal COMa. The correction information Cinf is an example of "waveform information" and "correspondence information."

[0023] The liquid ejection head 1 includes a switching circuit 18, a recording head 10, and a detection circuit 19. The detection circuit 19 is an example of a "detection section."

[0024] The print head 10 has M ejection sections D. In this embodiment, it is assumed that the value M is an even number equal to or greater than 2. Hereinafter, the m-th ejection section D of the M ejection sections D provided in the print head 10 may be referred to as ejection section D[m]. Here, the variable m is a natural number that satisfies "1≦m≦M." Furthermore, hereinafter, when a component or signal of the liquid ejection device 100 corresponds to a ejection section D[m] of the M ejection sections D, the subscript [m] may be added to the symbol representing the component or signal.

[0025] The switching circuit 18 switches whether to supply each drive signal COM to the discharge section D[m] based on the print signal SI. Note that, hereinafter, as shown in FIG. 5 and other figures, the drive signal COM supplied to the discharge section D[m] among the multiple drive signals COM may be referred to as an individual drive signal Vin[m]. The switching circuit 18 also switches whether to electrically connect the discharge section D[m] to the detection circuit 19 based on the print signal SI. When the discharge section D[m] is electrically connected to the detection circuit 19, for example, a detection signal Vout[m] detected from the discharge section D[m] is supplied to the detection circuit 19 via the switching circuit 18. The detection signal Vout[m] is, for example, an analog signal indicating the waveform of residual vibration, which is vibration remaining in the discharge section D[m] after the discharge section D[m] is driven by the individual drive signal Vin[m]. Specifically, for example, the detection signal Vout[m] indicates the waveform of the residual vibration of the diaphragm 14 after the piezoelectric element PZ[m] is driven. The piezoelectric element PZ and the diaphragm 14 will be described later with reference to FIGS.

[0026] The detection circuit 19 generates the residual vibration signal Vd[m] based on the detection signal Vout[m]. For example, the detection circuit 19 amplifies the amplitude of the detection signal Vout[m] or removes noise components contained in the detection signal Vout[m], thereby shaping the detection signal Vout[m] into a waveform suitable for processing in the analysis unit 3. In this way, the residual vibration signal Vd[m] is generated. For example, the detection circuit 19 may be configured to include a negative feedback amplifier for amplifying the detection signal Vout[m], a low-pass filter for attenuating high frequency components of the detection signal Vout[m], and a voltage follower for converting impedance and outputting a low-impedance residual vibration signal Vd[m].

[0027] For example, the residual vibration signal Vd[m] generated based on the detection signal Vout[m] is an analog signal that indicates the waveform of the residual vibration of the diaphragm 14 after the piezoelectric element PZ[m] is driven by the individual drive signal Vin[m]. The detection circuit 19 outputs the residual vibration signal Vd[m] generated based on the detection signal Vout[m] to the analysis unit 3. In this way, the detection circuit 19 detects the residual vibration of the diaphragm 14 after the piezoelectric element PZ[m] is driven based on the detection signal Vout[m].

[0028] The analysis unit 3 includes, for example, an ADC (Analog to Digital Converter) and converts the analog residual vibration signal Vd[m] into a digital signal. The analysis unit 3 then analyzes, for example, the residual vibration detected by the detection circuit 19 using the digitally converted residual vibration signal Vd[m]. The analysis unit 3 also generates residual vibration information Vinf indicating the analysis results of the residual vibration and outputs the generated residual vibration information Vinf to the control unit 4. The residual vibration information Vinf indicates, for example, the period, amplitude, and phase of the residual vibration. However, the residual vibration information Vinf may indicate only a portion of the period, amplitude, and phase of the residual vibration. Alternatively, the residual vibration information Vinf may include information other than the period, amplitude, and phase of the residual vibration. The waveform definition unit 40 described above, for example, determines the natural vibration period Tc of the pressure chamber CV based on the residual vibration information Vinf. The analysis unit 3 may be included in the control unit 4. For example, the control unit 4 may function as the analysis unit 3 by operating in accordance with the control program PG stored in the storage unit 5. Also, a part of the analysis unit 3 may be included in the control unit 4. Specifically, an ADC may be provided outside the control unit 4, and the control unit 4 may include a function of analyzing the residual vibration using the residual vibration signal Vd converted into a digital signal.

[0029] Furthermore, in this embodiment, as described above, the maintenance process is performed by the maintenance unit 7. For example, the maintenance unit 7 performs the maintenance process under the control of the control unit 4. The maintenance process includes, for example, a flushing process that discharges ink from the ejection section D, a wiping process that wipes off foreign matter such as ink adhering to the vicinity of the nozzle N of the ejection section D with a wiper, and a pumping process that sucks ink from inside the ejection section D with a tube pump or the like.

[0030] The maintenance unit 7 has a discharged ink receiving section for receiving the discharged ink when the ink in the discharge section D is discharged during the flushing process, a wiper for wiping off foreign matter such as ink adhering to the vicinity of the nozzle N of the discharge section D, and a tube pump for sucking ink, air bubbles, etc. from the discharge section D. The discharged ink receiving section, wiper, and tube pump are not shown in the drawings.

[0031] Next, the overall configuration of the liquid ejection device 100 will be described with reference to FIG.

[0032] Fig. 2 is a schematic diagram showing the configuration of the liquid ejection device 100. In Fig. 2, the ink container 60, the medium transport mechanism 8, and the carriage transport mechanism 9 will be mainly described.

[0033] The ink container 60 stores ink. Examples of the ink container 60 include a cartridge that is detachable from the liquid ejection device 100, a bag-shaped ink pack made of flexible film, and an ink tank that can be refilled with ink. The type of ink stored in the ink container 60 is not particularly limited and can be any type. As described above, this embodiment assumes that the liquid ejection device 100 has four liquid ejection heads 1, each corresponding to one of four inks: cyan, magenta, yellow, and black. Therefore, in this embodiment, the ink container 60 stores the four inks: cyan, magenta, yellow, and black. The ink container 60 supplies the stored ink to the liquid ejection head 1.

[0034] The medium conveying mechanism 8 conveys the medium PP in the Y1 direction along the Y axis under the control of the control unit 4. Hereinafter, the Y1 direction and the Y2 direction opposite to the Y1 direction will be collectively referred to as the Y-axis direction. Hereinafter, the X1 direction along the X axis intersecting the Y axis and the X2 direction opposite to the X1 direction will be collectively referred to as the X-axis direction. Hereinafter, the Z1 direction along the Z axis intersecting the X and Y axes and the Z2 direction opposite to the Z1 direction will be collectively referred to as the Z-axis direction. In this embodiment, as an example, a case will be described in which the X axis, Y axis, and Z axis are orthogonal to one another. However, the present invention is not limited to this example. It is sufficient that the X axis, Y axis, and Z axis intersect with one another.

[0035] The carriage transport mechanism 9 reciprocates the plurality of liquid ejection heads 1 in the X1 and X2 directions under the control of the control unit 4. As shown in Fig. 2, the carriage transport mechanism 9 has a substantially box-shaped carriage 91 that houses the plurality of liquid ejection heads 1, and an endless belt 92 to which the carriage 91 is fixed. Note that the ink containers 60 may be housed in the carriage 91 together with the liquid ejection heads 1.

[0036] The liquid ejection head 1 is driven by a drive signal COM under the control of a print signal SI, and ejects ink in the Z1 direction from some or all of the multiple nozzles N provided in the liquid ejection head 1. That is, the liquid ejection head 1 ejects ink from some or all of the multiple nozzles N in conjunction with the transport of the medium PP by the medium transport mechanism 8 and the reciprocating movement of the liquid ejection head 1 by the carriage transport mechanism 9, and forms a desired image on the surface of the medium PP by causing the ejected ink to land on the surface of the medium PP. In this embodiment, as described above, the Z1 direction is the direction in which ink is ejected from the nozzles N.

[0037] Next, the general structure of the liquid ejection head 1 will be described with reference to FIGS.

[0038] FIG. 3 is an exploded perspective view of the liquid ejection head 1. FIG. 4 is a cross-sectional view taken along line III-III in FIG. 3. The cross section taken along line III-III is parallel to the XZ plane and passes through inlets HL1 and HL2, which will be described later. In FIGS. 3 and 4, the numerals "1" and "2" are added to the end of the reference numerals of the nozzle rows Ln to distinguish between the two nozzle rows Ln, which will be described later. In addition, in FIGS. 3 and 4, for ease of explanation, the numeral "1" is added to the end of the reference numeral of the nozzle N included in the nozzle row Ln1, and the numeral "2" is added to the end of the reference numeral of the nozzle N included in the nozzle row Ln2.

[0039] 3 and 4, the liquid ejection head 1 has a nozzle substrate 11, compliance sheets CS1 and CS2, a communication plate 12, a pressure chamber substrate 13, a vibration plate 14, a sealing substrate 15, a flow path forming substrate 16, and a wiring board 17 on which electronic components EC are mounted. The electronic components EC include, for example, electrical circuits such as a switching circuit 18 and a detection circuit 19. For example, the recording head 10 is electrically connected to the switching circuit 18, the detection circuit 19, etc. via the wiring board 17.

[0040] As shown in FIG. 3, the recording head 10 includes, for example, a nozzle substrate 11, compliance sheets CS1 and CS2, a communication plate 12, a pressure chamber substrate 13, a vibration plate 14, a sealing substrate 15, and a flow path forming substrate 16.

[0041] The nozzle substrate 11 is a plate-like member that is elongated in the Y-axis direction and extends approximately parallel to the XY plane. Here, "approximately parallel" is a concept that includes not only completely parallel but also a case where it can be considered to be parallel when an error is taken into consideration. In this embodiment, "approximately parallel" is a concept that includes a case where it can be considered to be parallel when an error of about 10% is taken into consideration. Like "approximately parallel," the term "approximately perpendicular," which will be described later, is a concept that includes not only completely perpendicular but also perpendicular when an error is taken into consideration. The nozzle substrate 11 is manufactured by processing a silicon single crystal substrate using semiconductor manufacturing techniques such as etching, for example, but known materials and manufacturing methods may be arbitrarily adopted for manufacturing the nozzle substrate 11.

[0042] M nozzles N are formed on the nozzle substrate 11. Here, the nozzles N are through-holes formed in the nozzle substrate 11. In this embodiment, it is assumed that the multiple nozzles N formed on the nozzle substrate 11 include multiple nozzles N1 arranged to extend in the Y-axis direction and multiple nozzles N2 arranged to extend in the Y-axis direction at positions in the X2 direction as viewed from the multiple nozzles N1. Hereinafter, the multiple nozzles N1 extending in the Y-axis direction will be referred to as a nozzle row Ln1, and the multiple nozzles N2 extending in the Y-axis direction will be referred to as a nozzle row Ln2. For example, the number of nozzles N included in each of the nozzle rows LN1 and Ln2 is half the value M. Hereinafter, the nozzle row Ln1 and the nozzle row Ln2 may be collectively referred to as the nozzle row Ln. Also, in Figures 3 and 4, to make the explanation easier to understand, the numeral "1" is added to the end of the reference numeral of the component of the liquid ejection head 1 that corresponds to nozzle row Ln1, and the numeral "2" is added to the end of the reference numeral of the component that corresponds to nozzle row Ln2.

[0043] 3 and 4, a communicating plate 12 is provided at a position in the Z2 direction as viewed from the nozzle substrate 11. The communicating plate 12 is a plate-shaped member that is long in the Y-axis direction and extends approximately parallel to the XY plane. The communicating plate 12 is manufactured, for example, by processing a silicon single crystal substrate using semiconductor manufacturing technology, but the communicating plate 12 may be manufactured using any known material and method.

[0044] Ink flow paths are formed in the communicating plate 12. Specifically, the communicating plate 12 is formed with one supply flow path BA1 extending in the Y-axis direction and one supply flow path BA2 extending in the Y-axis direction at a position in the X2 direction as viewed from the supply flow path BA1. The communicating plate 12 also is formed with a plurality of connection flow paths BK1 corresponding to the plurality of nozzles N1, a plurality of connection flow paths BK2 corresponding to the plurality of nozzles N2, a plurality of communication flow paths BR1 corresponding to the plurality of nozzles N1, and a plurality of communication flow paths BR2 corresponding to the plurality of nozzles N2.

[0045] As shown in FIG. 4, the connection flow path BK1 communicates with the supply flow path BA1 and is provided so as to extend in the Z-axis direction at a position in the X2 direction as viewed from the supply flow path BA1. The communication flow path BR1 is provided so as to extend in the Z-axis direction at a position in the X2 direction as viewed from the connection flow path BK1. The communication flow path BR1 communicates with the nozzle N1 corresponding to the communication flow path BR1. The connection flow path BK2 communicates with the supply flow path BA2 and is provided so as to extend in the Z-axis direction at a position in the X1 direction as viewed from the supply flow path BA2. The communication flow path BR2 is provided so as to extend in the Z-axis direction at a position in the X1 direction as viewed from the connection flow path BK2 and at a position in the X2 direction as viewed from the communication flow path BR1. The communication flow path BR2 communicates with the nozzle N2 corresponding to the communication flow path BR2.

[0046] The supply flow paths BA1 and BA2 are also referred to as supply flow paths BA without any particular distinction, the connection flow paths BK1 and BK2 are also referred to as connection flow paths BK without any particular distinction, and the communicating flow paths BR1 and BR2 are also referred to as communicating flow paths BR without any particular distinction.

[0047] 3 and 4, a pressure chamber substrate 13 is provided at a position in the Z2 direction as viewed from the communication plate 12. The pressure chamber substrate 13 is a plate-shaped member that is long in the Y-axis direction and extends approximately parallel to the XY plane. The pressure chamber substrate 13 is manufactured, for example, by processing a silicon single crystal substrate using semiconductor manufacturing technology, but the pressure chamber substrate 13 may be manufactured using any known material and manufacturing method.

[0048] Ink flow paths are formed in the pressure chamber substrate 13. Specifically, the pressure chamber substrate 13 is formed with a plurality of pressure chambers CV1 corresponding to the plurality of nozzles N1 and a plurality of pressure chambers CV2 corresponding to the plurality of nozzles N2. Of these, the pressure chamber CV1 is provided so as to connect the X2-direction end of the connection flow path BK1 and the X1-direction end of the communication flow path BR1 and extend in the X-axis direction when viewed in the Z-axis direction. The pressure chamber CV2 is provided so as to connect the X1-direction end of the connection flow path BK2 and the X2-direction end of the communication flow path BR2 when viewed in the Z-axis direction and extend in the X-axis direction. The pressure chambers CV1 and CV2 are also referred to as pressure chambers CV without any particular distinction being made.

[0049] As shown in FIGS. 3 and 4 , a diaphragm 14 is provided at a position in the Z2 direction as viewed from the pressure chamber substrate 13. The diaphragm 14 is a plate-shaped member that is elongated in the Y-axis direction and extends substantially parallel to the XY plane, and is capable of elastically vibrating. In this embodiment, the diaphragm 14 has, for example, an elastic layer made of silicon oxide and an insulating layer made of zirconium oxide provided at a position in the Z2 direction as viewed from the elastic layer. That is, in this embodiment, the Z2-direction surface of the diaphragm 14 is formed of a non-conductive material. Here, the first-direction surface of element A is a surface of element A that is substantially perpendicular to the first direction and is the surface that is visible when element A is viewed from the first direction to the second direction. The second direction is the direction opposite to the first direction. Note that the elastic layer of the diaphragm 14 is not limited to an elastic layer made of silicon oxide. Similarly, the insulating layer of the diaphragm 14 is not limited to an insulating layer made of zirconium oxide.

[0050] 3 and 4, a plurality of piezoelectric elements PZ1 corresponding to the plurality of pressure chambers CV1 and a plurality of piezoelectric elements PZ2 corresponding to the plurality of pressure chambers CV2 are provided in positions in the Z2 direction as viewed from the vibration plate 14. Note that the piezoelectric elements PZ1 and PZ2 are also referred to as piezoelectric elements PZ without any particular distinction. The piezoelectric elements PZ are driven by the supply of a drive signal COM.

[0051] Although not shown in FIGS. 3 and 4 , the piezoelectric element PZ includes a common electrode Zc to which a predetermined bias potential VBS is supplied, an individual electrode Za to which an individual drive signal Vin is supplied, and a piezoelectric body Zb disposed between the individual electrode Za and the common electrode Zc, as shown in FIG. 5 . For example, the individual electrode Za, the piezoelectric body Zb, and the common electrode Zc are disposed in this order on the Z2-direction surface of the diaphragm 14 along the Z2 direction. Here, the expression “element B is formed on the surface of element A” in this specification does not intend to limit the configuration to one in which element A and element B are in direct contact with each other. In other words, even if element C is formed on the surface of element A and element B is formed on the surface of element C, the concept of “element B is formed on the surface of element A” is encompassed as long as at least a portion of element A and element B overlap in a planar view. Note that in this embodiment, the common electrode Zc is a so-called upper electrode and the individual electrode Za is a so-called lower electrode. However, the common electrode Zc may be a lower electrode and the individual electrode Za may be an upper electrode.

[0052] The piezoelectric element PZ is a passive element that deforms in response to changes in the potential of the drive signal COM supplied to the individual electrode Za as the individual drive signal Vin. In other words, the piezoelectric element PZ is an example of an energy conversion element that converts the electrical energy of the drive signal COM into kinetic energy. Specifically, the piezoelectric element PZ is driven and deforms in response to changes in the potential of the drive signal COM.

[0053] As shown in FIGS. 3 and 4, a piezoelectric element PZ is provided on the Z2-direction surface of the vibration plate 14, and therefore the vibration plate 14 vibrates in conjunction with the deformation of the piezoelectric element PZ. That is, the vibration plate 14 vibrates when the piezoelectric element PZ is driven. When the vibration plate 14 vibrates, the pressure in the pressure chamber CV fluctuates. Then, as the pressure in the pressure chamber CV fluctuates, ink filled in the pressure chamber CV is ejected from the nozzle N via the communication flow path BR. In this way, the pressure chamber CV is filled with ink, and pressure for ejecting the ink from the nozzle N is applied by the vibration of the vibration plate 14. Furthermore, the vibration remaining in the ejection portion D[m] described in FIG. 1 can also be considered, for example, as vibration remaining in the ink in the pressure chamber CV of the ejection portion D.

[0054] 3 and 4, a sealing substrate 15 for protecting the plurality of piezoelectric elements PZ1 and the plurality of piezoelectric elements PZ2 is provided at a position in the Z2 direction as viewed from the pressure chamber substrate 13. The sealing substrate 15 is a plate-like member that is elongated in the Y-axis direction and extends approximately parallel to the XY plane. The sealing substrate 15 is manufactured, for example, by processing a silicon single crystal substrate using semiconductor manufacturing technology, but the sealing substrate 15 may be manufactured using any known material and manufacturing method.

[0055] 4, the surface of the sealing substrate 15 in the Z1 direction is provided with recesses for covering the plurality of piezoelectric elements PZ1 and recesses for covering the plurality of piezoelectric elements PZ2. Hereinafter, the sealed space covering the plurality of piezoelectric elements PZ1 and formed between the vibration plate 14 and the sealing substrate 15 will be referred to as the sealed space SP1, and the sealed space covering the plurality of piezoelectric elements PZ2 and formed between the vibration plate 14 and the sealing substrate 15 will be referred to as the sealed space SP2. The sealed spaces SP1 and SP2 will also be referred to as the sealed space SP without any particular distinction. The sealed space SP is a space for sealing the piezoelectric elements PZ and preventing the piezoelectric elements PZ from being altered by the influence of moisture, etc.

[0056] A through hole 15h is provided in the sealing substrate 15. When the sealing substrate 15 is viewed in the Z1 direction, the through hole 15h is located between the sealed space SP1 and the sealed space SP2, and is a hole that penetrates from the surface of the sealing substrate 15 in the Z1 direction to the surface of the sealing substrate 15 in the Z2 direction. The wiring substrate 17 is inserted into the through hole 15h.

[0057] 3 and 4, a flow path forming substrate 16 is provided at a position in the Z2 direction as viewed from the communication plate 12. The flow path forming substrate 16 is a plate-like member that is elongated in the Y-axis direction and extends substantially parallel to the XY plane. The flow path forming substrate 16 is formed, for example, by injection molding of a resin material, but the flow path forming substrate 16 may be manufactured using any known material and method.

[0058] As shown in FIG. 4, ink flow paths are formed in the flow path forming substrate 16. Specifically, one supply flow path BB1 and one supply flow path BB2 are formed in the flow path forming substrate 16. Of these, supply flow path BB1 communicates with supply flow path BA1 and is provided so as to extend in the Y-axis direction at a position in the Z2 direction as viewed from supply flow path BA1. Supply flow path BB2 communicates with supply flow path BA2 and is provided so as to extend in the Y-axis direction at a position in the Z2 direction as viewed from supply flow path BA2 and at a position in the X2 direction as viewed from supply flow path BB1. Note that supply flow paths BB1 and BB2 are also referred to as supply flow paths BB without any particular distinction being made.

[0059] The flow channel forming substrate 16 is provided with an inlet HL1 that communicates with the supply channel BB1 and an inlet HL2 that communicates with the supply channel BB2. Ink is supplied to the supply channel BB1 from the ink container 60 via the inlet HL1. The ink supplied to the supply channel BB1 from the ink container 60 via the inlet HL1 flows into the supply channel BA1. Some of the ink that flows into the supply channel BA1 passes through the connecting channel BK1 and fills the pressure chamber CV1. When the piezoelectric element PZ1 is driven by the drive signal COM, some of the ink that has filled the pressure chamber CV1 is ejected from the nozzle N1 via the communicating channel BR1.

[0060] Furthermore, ink is supplied to supply flow path BB2 from the ink container 60 via inlet HL2. The ink supplied from the ink container 60 to supply flow path BB2 via inlet HL2 flows into supply flow path BA2. Some of the ink that flows into supply flow path BA2 passes through connecting flow path BK2 and fills pressure chamber CV2. When piezoelectric element PZ2 is driven by drive signal COM, some of the ink that has filled pressure chamber CV2 is ejected from nozzle N2 via communicating flow path BR2.

[0061] A through hole 16h is provided in the flow path forming substrate 16. When the flow path forming substrate 16 is viewed in the Z1 direction, the through hole 16h is located between the supply flow path BB1 and the supply flow path BB2, and is a hole that penetrates from the surface of the flow path forming substrate 16 in the Z1 direction to the surface of the flow path forming substrate 16 in the Z2 direction. The wiring substrate 17 is inserted into the through hole 16h.

[0062] 3 and 4, a wiring board 17 is mounted on the Z2 direction surface of the diaphragm 14. The wiring board 17 is a component for electrically connecting the liquid ejection head 1 to the control unit 4. For example, a flexible wiring board such as an FPC (Flexible Printed Circuit) or an FFC (Flexible Flat Cable) is preferably used as the wiring board 17. As described above, electronic components EC including the switching circuit 18 and the detection circuit 19 are mounted on the wiring board 17.

[0063] 3 and 4, a compliance sheet CS1 is provided in a position in the Z1 direction as viewed from the communicating plate 12 so as to block the supply flow path BA1 and the connecting flow path BK1, and a compliance sheet CS2 is provided so as to block the supply flow path BA2 and the connecting flow path BK2. The compliance sheets CS1 and CS2 are also referred to as the compliance sheet CS without any particular distinction. The compliance sheet CS is a plate-like member that is elongated in the Y-axis direction and extends substantially parallel to the XY plane. The compliance sheet CS is made of an elastic material and absorbs pressure fluctuations of the ink in the supply flow path BA and the connecting flow path BK.

[0064] 4, ejection section D1 has a piezoelectric element PZ1, a pressure chamber CV1, a nozzle N1 communicating with the pressure chamber CV1, and a portion of the vibration plate 14 that contacts the piezoelectric element PZ1. Similarly, ejection section D2 has a piezoelectric element PZ2, a pressure chamber CV2, a nozzle N2 communicating with the pressure chamber CV2, and a portion of the vibration plate 14 that contacts the piezoelectric element PZ2. Note that ejection sections D1 and D2 are also referred to as ejection section D without any particular distinction being made.

[0065] Although not shown, the liquid ejection head 1 also has a cap for sealing the nozzle surface, which is the surface in the Z1 direction of the nozzle substrate 11. The cap seals the nozzle surface of the nozzle substrate 11 on which the nozzles N are formed, during periods when ink is not ejected from the nozzles N.

[0066] Next, an overview of the liquid ejection head 1 will be described with reference to FIG.

[0067] FIG. 5 is a block diagram showing an example of the configuration of the liquid ejection head 1. As shown in FIG.

[0068] 1, the liquid ejection head 1 has a recording head 10, a switching circuit 18, and a detection circuit 19. The liquid ejection head 1 also has a wiring La to which a drive signal COMa is supplied from the drive signal generation unit 2, and a wiring Lb to which a drive signal COMb is supplied from the drive signal generation unit 2. The liquid ejection head 1 also has a wiring Ls that supplies a detection signal Vout to the detection circuit 19, a wiring Li[m] that supplies an individual drive signal Vin[m] to the ejection section D[m], and a wiring Ld to which a bias potential VBS is supplied.

[0069] The switching circuit 18 has M switches SWa[1] to SWa[M] that correspond one-to-one to the M discharge units D[1] to D[M], M switches SWb[1] to SWb[M] that correspond one-to-one to the M discharge units D[1] to D[M], and M switches SWs[1] to SWs[M] that correspond one-to-one to the M discharge units D[1] to D[M].

[0070] The switching circuit 18 also includes a connection state designation circuit CSC. The connection state designation circuit CSC designates the connection states of the M switches SWa, M switches SWb, and M switches SWs. For example, the connection state designation circuit CSC generates connection state designation signals Qa[m], Qb[m], and Qs[m] based on at least some of the print signal SI, latch signal LAT, and period specification signal Tsig supplied from the control unit 4.

[0071] For example, the connection state designation signal Qa[m] is a signal that designates the on / off state of the switch SWa[m], the connection state designation signal Qb[m] is a signal that designates the on / off state of the switch SWb[m], and the connection state designation signal Qs[m] is a signal that designates the on / off state of the switch SWs[m].

[0072] The switch SWa[m] switches between conduction and non-conduction between the wiring La and the individual electrode Za[m] of the piezoelectric element PZ[m] provided in the discharge section D[m] based on the connection state designation signal Qa[m]. That is, the switch SWa[m] switches between conduction and non-conduction between the wiring La and the wiring Li[m] connected to the individual electrode Za[m] based on the connection state designation signal Qa[m]. In this embodiment, the switch SWa[m] is turned on when the connection state designation signal Qa[m] is high level and turned off when it is low level. When the switch SWa[m] is on, the drive signal COMa supplied to the wiring La is supplied as the individual drive signal Vin[m] to the individual electrode Za[m] of the discharge section D[m] via the wiring Li[m].

[0073] The switch SWb[m] switches between conduction and non-conduction between the wiring Lb and the individual electrode Za[m] of the piezoelectric element PZ[m] provided in the discharge section D[m] based on the connection state designation signal Qb[m]. That is, the switch SWb[m] switches between conduction and non-conduction between the wiring Lb and the wiring Li[m] connected to the individual electrode Za[m] based on the connection state designation signal Qb[m]. In this embodiment, the switch SWb[m] is turned on when the connection state designation signal Qb[m] is high level and turned off when the connection state designation signal Qb[m] is low level. When the switch SWb[m] is on, the drive signal COMb supplied to the wiring Lb is supplied as the individual drive signal Vin[m] to the individual electrode Za[m] of the discharge section D[m] via the wiring Li[m].

[0074] The switch SWs[m] switches between electrical continuity and non-conduction between the wiring Ls and the individual electrode Za[m] of the piezoelectric element PZ[m] provided in the discharge portion D[m] based on the connection state designation signal Qs[m]. That is, the switch SWs[m] switches between electrical continuity and non-conduction between the wiring Ls and the wiring Li[m] connected to the individual electrode Za[m] based on the connection state designation signal Qs[m]. In this embodiment, the switch SWs[m] is turned on when the connection state designation signal Qs[m] is high level and turned off when the connection state designation signal Qs[m] is low level.

[0075] For example, the connection state designation signal Qs[m] becomes high level when detecting residual vibration of a discharge portion D[m]. Hereinafter, the discharge portion D whose residual vibration is detected may be referred to as the discharge portion D of the detection target. When the switch SWs[m] is turned on, a detection signal Vout[m] indicating the potential of the individual electrode Za[m] of the piezoelectric element PZ[m] of the discharge portion D[m] of the detection target is supplied to the detection circuit 19 via the wiring Li[m] and the wiring Ls. The detection circuit 19 generates a residual vibration signal Vd[m] based on the detection signal Vout[m].

[0076] As described above, the individual drive signal Vin[m] is a signal of the drive signals COMa and COMb that is supplied to the piezoelectric element PZ[m] of the discharge section D[m] via the switch SWa[m] or SWb[m].

[0077] Next, the operation of the liquid ejection device 100 in the unit period Tu will be described with reference to FIG.

[0078] 6 is a timing chart showing an example of the operation of the liquid ejection device 100 in a unit period Tu. In this embodiment, when the liquid ejection device 100 executes a printing process, a printing process period including one or more unit periods Tu is set as the operating period of the liquid ejection device 100. The liquid ejection device 100 according to this embodiment can drive each ejection section D for the printing process in each unit period Tu. Furthermore, the liquid ejection device 100 according to this embodiment can drive the ejection section D to be detected and detect the detection signal Vout[m] from the ejection section D to be detected in each unit period Tu.

[0079] The control unit 4 outputs a latch signal LAT having a pulse PLL, thereby defining a unit period Tu as the period from the rising edge of the pulse PLL to the rising edge of the next pulse PLL.

[0080] The print signal SI includes, for example, M individual designation signals Sd[1] to Sd[M] that correspond one-to-one to the M discharge sections D[1] to D[M]. The individual designation signal Sd[m] designates the driving mode of the discharge section D[m] in each unit period Tu when the liquid discharger 100 executes a printing process.

[0081] Prior to each unit period Tu during which printing is performed, the control unit 4 supplies a print signal SI, including individual designation signals Sd[1] to Sd[M], to the connection state designation circuit CSC in synchronization with the clock signal CL. Then, during that unit period Tu, the connection state designation circuit CSC generates connection state designation signals Qa[m], Qb[m], and Qs[m] based on the individual designation signal Sd[m].

[0082] For example, during the unit period TP in which the printing process is executed, the discharge section D[m] is designated by the individual designation signal Sd[m] as either a discharge section D that forms dots, a discharge section D that does not form dots, or a discharge section D to be detected.

[0083] First, the operation of the connection state specification circuit CSC and the like when the drive mode of the discharge section D that forms dots is specified by the individual specification signal Sd[m] will be described.

[0084] The drive signal generation unit 2 outputs a drive signal COMa having a pulse PA. The pulse PA is, for example, a pulse that causes ink to be ejected from the nozzle N. The pulse PA has a waveform in which the potential of the drive signal COMa changes from potential V0, passes through potential VLa which is lower than potential V0, and potential VHa which is higher than potential V0, and then returns to potential V0. Potential V0 is the potential at the start and end of the pulse PA, and is the reference potential of the drive signal COMa.

[0085] For example, the pulse PA has a waveform element Pa1 whose potential changes from potential V0 to potential VLa, a waveform element Pa2 whose potential is maintained at the potential VLa at the end of the waveform element Pa1, and a waveform element Pa3 whose potential changes from potential VLa to potential VHa. The pulse PA further includes a waveform element Pa4 whose potential is maintained at the potential VHa at the end of the waveform element Pa3, and a waveform element Pa5 whose potential changes from potential VHa to potential V0.

[0086] The waveform elements Pa1 and Pa5 are expansion elements for displacing the piezoelectric body Zb in the Z2 direction. In the expansion elements, the potential of the drive signal COMa changes to drive the piezoelectric element PZ so as to expand the volume of the pressure chamber CV. Therefore, in the waveform elements Pa1 and Pa5, the potential of the drive signal COMa changes so as to expand the volume of the pressure chamber CV. When the volume of the pressure chamber CV expands, the surface of the ink in the nozzle N is pulled in the Z2 direction, which is the opposite direction to the ejection direction. Hereinafter, pulling the surface of the ink in the nozzle N in the direction opposite to the ejection direction may be referred to as "pull."

[0087] Furthermore, the waveform element Pa3 is a contraction element for displacing the piezoelectric body Zb in the Z1 direction. In the contraction element, the potential of the drive signal COMa changes to drive the piezoelectric element PZ so as to contract the volume of the pressure chamber CV. Therefore, in the waveform element Pa3, the potential of the drive signal COMa changes so as to contract the volume of the pressure chamber CV. When the volume of the pressure chamber CV contracts, the surface of the ink in the nozzle N is pushed in the Z1 direction, which is the ejection direction. Hereinafter, pushing the surface of the ink in the nozzle N in the ejection direction may be referred to as a push.

[0088] Furthermore, waveform elements Pa2 and Pa4 are maintaining elements for maintaining the position of piezoelectric body Zb in the Z-axis direction. For example, waveform element Pa2 maintains the potential of drive signal COMa in order to drive piezoelectric element PZ so as to maintain the volume of pressure chamber CV expanded by waveform element Pa1. For example, waveform element Pa4 maintains the potential of drive signal COMa in order to drive piezoelectric element PZ so as to maintain the volume of pressure chamber CV contracted by waveform element Pa3.

[0089] In this way, the pulse PA has a so-called pull-push-pull waveform. However, the waveform of the drive signal COMa that causes ink to be ejected from the nozzle N is not limited to the pull-push-pull waveform.

[0090] The pulse PA is determined so that a predetermined amount of ink is ejected from the ejection section D[m] when an individual drive signal Vin[m] having the pulse PA is supplied to the ejection section D[m]. Note that in this embodiment, it is assumed that when the potential of the individual drive signal Vin[m] is high, the volume of the pressure chamber CV of the ejection section D[m] is smaller than when the potential is low. Therefore, when the ejection section D[m] is driven by the individual drive signal Vin[m] having the pulse PA, the ink in the ejection section D[m] is ejected from the nozzle N by the waveform element Pa3, in which the potential of the individual drive signal Vin[m] changes from low to high.

[0091] For example, the waveform elements Pa1, Pa2, Pa3, Pa4, and Pa5 included in the pulse PA are determined based on the ink ejection characteristics of the ejection unit D. The ink ejection characteristics include, for example, the amount of ink ejected as ink droplets and the ejection speed of the ejected ink droplets.

[0092] Here, variations in the natural vibration period Tc of the pressure chamber CV cause variations in the ink ejection characteristics. For this reason, in this embodiment, the waveform of the drive signal COMa, i.e., the waveform of the pulse PA, is determined based on the natural vibration period Tc of the pressure chamber CV. In this embodiment, the length TA1 of the waveform element Pa2 and the length TA2 of the waveform element Pa4 are corrected based on the natural vibration period Tc of the pressure chamber CV, relative to a reference waveform, which is a predetermined waveform of the pulse PA. Note that this embodiment assumes that the start timing of the waveform element Pa2 and the start timing of the waveform element Pa4, relative to the start timing of the waveform element Pa1 as the starting point, do not change before and after the correction of the lengths TA1 and TA2.

[0093] Therefore, for example, when the length TA1 is long, the amount of potential change per unit time of the waveform element Pa3, i.e., the slope of the waveform element Pa3, is larger than when the length TA1 is short. For example, when the slope of the waveform element Pa3 is large, the ink droplet ejection speed is faster than when the slope of the waveform element Pa3 is small. Furthermore, when the length TA2 is long, the amount of potential change per unit time of the waveform element Pa5, i.e., the slope of the waveform element Pa5, is larger than when the length TA2 is short. When the slope of the waveform element Pa5 is large, the vibration damping ability to attenuate residual vibration of the ejection section D is higher than when the slope of the waveform element Pa5 is small. Note that the method of correcting the waveform of the pulse PA, i.e., the method of determining the waveform of the pulse PA, is not limited to correcting the length TA1 of the waveform element Pa2 and the length TA2 of the waveform element Pa4. For example, one or both of the potentials VHa and VLa may be corrected for the reference waveform of the pulse PA based on the natural vibration period Tc of the pressure chamber CV. For example, for the reference waveform of the pulse PA, the slope of the waveform element Pa3 and the slope of the waveform element Pa5 may be corrected based on the natural vibration period Tc of the pressure chamber CV without changing the length TA1 of the waveform element Pa2 and the length TA2 of the waveform element Pa4. For example, for the reference waveform of the pulse PA, some or all of the potential VHa, potential VLa, length TA1, length TA2, slope of the waveform element Pa3, and slope of the waveform element Pa5 may be corrected based on the natural vibration period Tc of the pressure chamber CV.

[0094] The natural vibration period Tc of the pressure chamber CV used to determine the waveform of the pulse PA is a natural vibration period representative of the natural vibration periods of the M pressure chambers CV. For example, the natural vibration period Tc representative of the natural vibration periods of the M pressure chambers CV may be the natural vibration period of one of the M pressure chambers CV. Alternatively, the natural vibration period Tc representative of the natural vibration periods of the M pressure chambers CV may be statistically determined using the natural vibration periods of K pressure chambers CV. For example, the natural vibration period Tc representative of the natural vibration periods of the M pressure chambers CV may be the average value of the natural vibration periods of the K pressure chambers CV, or may be the maximum or minimum value of the natural vibration periods of the K pressure chambers CV. The value K is a natural number that satisfies the relationship "2≦K≦M."

[0095] Next, the operation of the connection state designation circuit CSC and the like when the drive mode of the discharge section D to be detected is designated by the individual designation signal Sd[m] will be described.

[0096] For example, the drive signal generating unit 2 outputs a drive signal COMb having a pulse PS. The pulse PS has a waveform in which the potential of the drive signal COMb changes from a potential V0 to a potential VLs lower than the potential V0, passes through a potential VHs higher than the potential V0, and returns to the potential V0. In this embodiment, the pulse PS is determined so that the potential difference between the potential VHs, which is the highest potential of the pulse PS, and the potential VLs, which is the lowest potential, is smaller than the potential difference between the potential VHa, which is the highest potential of the pulse PA, and the potential VLa, which is the lowest potential. Specifically, when the drive signal COMb having the pulse PS is supplied to the ejection section D[m], the waveform of the pulse PS is determined so that the ejection section D[m] is driven to such an extent that ink is not ejected from the ejection section D[m]. The potential of the pulse PS is set to the potential V0 at the start and end.

[0097] The control unit 4 also outputs a period defining signal Tsig having a pulse PLSt1 and a pulse PLSt2, thereby dividing the unit period Tu into a control period TSS1 from the start of the pulse PLL to the start of the pulse PLSt1, a control period TSS2 from the start of the pulse PLSt1 to the start of the pulse PLSt2, and a control period TSS3 from the start of the pulse PLSt2 to the start of the next pulse PLL.

[0098] For example, when the individual designation signal Sd[m] designates the discharge portion D[m] as the discharge portion D to be detected, the connection state designation circuit CSC sets the connection state designation signal Qa[m] to a low level in the unit period Tu. The connection state designation circuit CSC also sets the connection state designation signal Qb[m] to a high level in the control periods TSS1 and TSS3, and to a low level in the control period TSS2. The connection state designation circuit CSC also sets the connection state designation signal Qs[m] to a low level in the control periods TSS1 and TSS3, and to a high level in the control period TSS2.

[0099] In this case, the piezoelectric element PZ[m] of the discharge section D[m] to be detected is driven by the pulse PS of the drive signal COMb during the control period TSS1. Specifically, the piezoelectric element PZ[m] is displaced by the pulse PS of the drive signal COMb during the control period TSS1. As a result, vibration occurs in the discharge section D[m] to be detected. The vibration generated during the control period TSS1 remains during the control period TSS2. Then, during the control period TSS2, the potential of the individual electrode Za[m] of the piezoelectric element PZ[m] of the discharge section D[m] to be detected changes depending on the residual vibration generated in the discharge section D[m]. That is, during the control period TSS2, the potential of the individual electrode Za of the piezoelectric element PZ of the discharge section D to be detected becomes a potential corresponding to the electromotive force of the piezoelectric element PZ caused by the residual vibration generated in the discharge section D to be detected. Then, the potential of the individual electrode Za is detected as the detection signal Vout during the control period TSS2.

[0100] Furthermore, when the driving mode of the ejection section D that does not form dots is specified by the individual specification signal Sd[m], for example, the connection state specification circuit CSC sets the connection state specification signals Qa[m], Qb[m] and Qs[m] to a low level in the unit period Tu.

[0101] The operation of the liquid ejection device 100 is not limited to the example shown in Fig. 6. For example, Fig. 6 illustrates a case where one drive signal COM is used to eject ink from the nozzle N, but the present invention is not limited to this example. For example, a plurality of drive signals COM corresponding to the size of the dot may be used as the drive signal COM to eject ink from the nozzle N. Furthermore, the plurality of drive signals COM may include a drive signal COM having a micro-vibration waveform to prevent the ink from thickening.

[0102] 6 illustrates an example in which the detection signal Vout indicating the residual vibration of the ejection section D to be detected is generated during the printing process period, but the detection signal Vout may be generated during a period other than the printing process period. In other words, a process for detecting the residual vibration of the ejection section D to be detected may be executed during a period other than the printing process period.

[0103] Next, the operation of the analysis unit 3 will be described with reference to FIG.

[0104] Fig. 7 is a diagram showing an example of the waveform of the residual vibration signal Vd. Fig. 7 schematically shows an example of the waveform of the residual vibration signal Vd. The vertical axis of the diagram represents the potential of the residual vibration signal Vd, and the horizontal axis represents time.

[0105] As described above, the residual vibration signal Vd indicates a waveform corresponding to the residual vibration occurring in the ejection portion D to be detected, i.e., the residual vibration of the diaphragm 14. Specifically, the residual vibration signal Vd indicates a period corresponding to the period of the residual vibration of the diaphragm 14, an amplitude corresponding to the amplitude of the residual vibration of the diaphragm 14, and a phase corresponding to the phase of the residual vibration of the diaphragm 14.

[0106] 7, peaks VPp1 and VPp2 indicate peaks VPp where the potential of residual vibration signal Vd is at its maximum value, i.e., where the waveform of residual vibration signal Vd reaches its peak. Furthermore, peaks VPm1 and VPm2 indicate peaks VPm where the potential of residual vibration signal Vd is at its minimum value, i.e., where the waveform of residual vibration signal Vd reaches its valley. Potential Vc indicates the reference potential of residual vibration signal Vd. For example, potential Vc may be the potential of residual vibration signal Vd when the residual vibration of diaphragm 14 has attenuated and subsided, or may be an intermediate potential between the potential of peak VPp and the potential of peak VPm.

[0107] Furthermore, timing Tc1 indicates the timing at which the potential of the residual vibration signal Vd becomes potential Vc when the potential of the residual vibration signal Vd changes from the potential of peak VPp1 to the potential of peak Vpm1. Timing Tc2 indicates the timing at which the potential of the residual vibration signal Vd becomes potential Vc when the potential of the residual vibration signal Vd changes from the potential of peak VPp2 to the potential of peak Vpm2. Furthermore, duration TPc indicates the time from timing Tc1 to timing Tc2. In other words, duration TPc is determined based on the timing at which the potential of the residual vibration signal Vd becomes potential Vc. Furthermore, duration TPm indicates the time from timing Tm1 of peak VPm1 to timing Tm2 of peak VPm2. In other words, duration TPm is determined based on the timing of peak VPm.

[0108] For example, the analysis unit 3 identifies the period of the residual vibration signal Vd as the period of the residual vibration of the diaphragm 14. The period of the residual vibration signal Vd may be, for example, a time length TPc or a time length TPm. Alternatively, the period of the residual vibration signal Vd may be a time length TPv, which is the time from timing Tv1 to timing Tv2. Timing Tv1 is the intermediate timing between the timings at which the potential of the residual vibration signal Vd becomes an arbitrary potential VV1 between the potential Vc and the potential of the peak VPm1 before and after timing Tm1. Timing Tv2 is the intermediate timing between the timings at which the potential of the residual vibration signal Vd becomes an arbitrary potential VV2 between the potential Vc and the potential of the peak VPm2 before and after timing Tm2. Note that the potential Vc may be the potential VV1 or VV2. In an aspect in which the time length TPv is the period of the residual vibration signal Vd, it is expected that the influence of distortion will be reduced even if the waveform of the residual vibration signal Vd is distorted.

[0109] The method for determining the period of the residual vibration signal Vd is not limited to the above example, and any known method can be used. For example, the period of the residual vibration signal Vd may be the average of multiple time lengths determined based on the timing at which the potential of the residual vibration signal Vd becomes the potential Vc, or may be the average of multiple time lengths determined based on the timing of the peak VPm. Alternatively, the period of the residual vibration signal Vd may be the length of time determined based on the timing of the peak VPp, or may be the average of multiple time lengths determined based on the timing of the peak VPp. In this embodiment, it is assumed that the time length TPc is determined as the period of the residual vibration signal Vd.

[0110] Furthermore, for example, the analysis unit 3 identifies the amplitude of the residual vibration signal Vd as the amplitude of the residual vibration of the diaphragm 14. The amplitude of the residual vibration signal Vd may be, for example, the amplitude of the peak VPp or the amplitude of the peak VPm. In this embodiment, it is assumed that the amplitude λc of the peak VPm1, where the waveform of the residual vibration signal Vd first reaches a valley, is identified as the amplitude of the residual vibration signal Vd. The amplitude λc of the peak VPm1 is the absolute value of the difference between the potential of the peak VPm1 and the potential Vc.

[0111] The method for determining the amplitude of the residual vibration signal Vd is not limited to the above example, and any known method can be used. For example, the amplitude of the residual vibration signal Vd may be the amplitude of the first or second peak VPp, or may be the average of the amplitudes of multiple peaks VPp. Alternatively, the amplitude of the residual vibration signal Vd may be the amplitude of the second peak VPm, or may be the average of the amplitudes of multiple peaks VPm. Furthermore, the amplitude of the residual vibration signal Vd may be the average of the amplitudes of one or more peaks VPp and one or more peaks VPm.

[0112] Furthermore, for example, the analysis unit 3 identifies the phase of the residual vibration signal Vd as the phase of the residual vibration of the diaphragm 14. The method for identifying the phase of the residual vibration signal Vd is not particularly limited, and any known method can be employed.

[0113] The analysis unit 3 outputs to the control unit 4, for example, a time length TPc identified as the period of the residual vibration signal Vd, an amplitude λc identified as the amplitude of the residual vibration signal Vd, and residual vibration information Vinf indicating the phase of the residual vibration signal Vd.

[0114] Next, with reference to FIG. 8, the correction information Cinf that is referenced when determining the waveform of the drive signal COMa will be described.

[0115] Fig. 8 is an explanatory diagram illustrating the correction information Cinf that is referenced when determining the waveform of the drive signal COMa. Note that Fig. 8 also shows the waveform of the drive signal COMa as a note. In this embodiment, it is assumed that one piece of correction information Cinf is prepared for each liquid ejection head 1. Fig. 8 shows an example of the correction information Cinf that corresponds to one liquid ejection head 1 out of the multiple liquid ejection heads 1.

[0116] As described above, the correction information Cinf indicates the correspondence relationship between the natural vibration period Tc of the pressure chamber CV and the waveform of the drive signal COMa. In this embodiment, it is assumed that the correction information Cinf indicates the correspondence relationship between the waveform of the drive signal COMa and the natural vibration period Tc determined based on the residual vibration detected when the pressure chamber CV is filled with ink before shipping the liquid ejection head 1. Furthermore, in this embodiment, it is assumed that the period of the residual vibration signal Vd is determined as the natural vibration period Tc of the pressure chamber CV. For example, in this embodiment, it is assumed that the time length TPc is determined as the period of the residual vibration signal Vd, and therefore the waveform definition unit 40 determines the time length TPc indicated by the residual vibration information Vinf as the natural vibration period Tc of the pressure chamber CV.

[0117] 6, the length TA1 of the waveform element Pa2 and the length TA2 of the waveform element Pa4 in the reference waveform of the pulse PA are corrected based on the natural vibration period Tc of the pressure chamber CV. Hereinafter, the length TA1 of the waveform element Pa2 in the reference waveform of the pulse PA will also be referred to as the length TA1 of the waveform element Pa2 of the reference waveform, and the length TA2 of the waveform element Pa4 in the reference waveform of the pulse PA will also be referred to as the length TA2 of the waveform element Pa4 of the reference waveform. For example, in this embodiment, as shown in FIG. 8, the correction information Cinf indicates the relationship between the correction value for the length TA1 of the waveform element Pa2 of the reference waveform and the correction value for the length TA2 of the waveform element Pa4 of the reference waveform, and the natural vibration period Tc of the pressure chamber CV.

[0118] 8, the length TA1 of waveform element Pa2 is determined by multiplying the length TA1 of waveform element Pa2 of the reference waveform by the correction value for length TA1, and the length TA2 of waveform element Pa4 is determined by multiplying the length TA2 of waveform element Pa4 of the reference waveform by the correction value for length TA2. Note that the correction of lengths TA1 and TA2 does not necessarily have to be by multiplication, and other methods such as addition and subtraction may also be used.

[0119] The natural vibration period Tc of the pressure chamber CV is divided, for example, using a threshold value Tth1 and a threshold value Tth2 that is greater than the threshold value Tth1. For example, if the natural vibration period Tc of the pressure chamber CV is smaller than the threshold value Tth1, the correction value for the length TA1 is 0.9, and the correction value for the length TA2 is 0.8. If the natural vibration period Tc of the pressure chamber CV is equal to or greater than the threshold value Tth1 and equal to or less than the threshold value Tth2, the correction values for the length TA1 and the length TA2 are both 1.0. If the natural vibration period Tc of the pressure chamber CV is greater than the threshold value Tth2, the correction value for the length TA1 is 1.2, and the correction value for the length TA2 is 1.1. In the example shown in FIG. 8, the reference waveform of the pulse PA is defined assuming that the natural vibration period Tc of the pressure chamber CV is equal to or greater than the threshold value Tth1 and equal to or less than the threshold value Tth2.

[0120] In this way, the waveform defining unit 40 determines the waveform of the drive signal COMa based on the natural vibration period Tc of the pressure chamber CV, the correction information Cinf, and the reference waveform of the pulse PA. That is, in this embodiment, the waveform of the drive signal COMa can be determined based on the natural vibration period Tc of the pressure chamber CV under the actual usage conditions of the liquid ejection device 100 and the correction information Cinf prepared in advance. As a result, in this embodiment, the waveform of the drive signal COM that drives the piezoelectric element PZ can be appropriately and easily determined.

[0121] The content of the correction information Cinf is not limited to the example shown in FIG. 8. For example, the correction values for length TA1 and length TA2 may be values other than the example values shown in FIG. 8. The correction values can also be changed as appropriate depending on the correction method. Furthermore, the number of divisions of the natural vibration period Tc of the pressure chamber CV when determining the waveform of the drive signal COMa is not limited to three. For example, the number of divisions of the natural vibration period Tc of the pressure chamber CV when determining the waveform of the drive signal COMa may be two, or four or more. Furthermore, the waveform of the drive signal COMa may be determined without using the reference waveform of the pulse PA. For example, the correction information Cinf may be information indicating the waveform of the pulse PA for each division of the natural vibration period Tc of the pressure chamber CV.

[0122] Next, with reference to FIG. 9, the operation of the liquid ejection device 100 when determining the waveform of the drive signal COMa will be described.

[0123] Fig. 9 is a flowchart showing an example of the operation of the liquid ejection device 100 when determining the waveform of the drive signal COMa. The timing at which the operation shown in Fig. 9 is performed is not particularly limited, but it is preferable that the operation be performed when the liquid ejection device 100 is used for the first time, or when the operating conditions of the liquid ejection device 100 are changed due to a change in the type of ink used, etc. The operating conditions of the liquid ejection device 100 also include the operating conditions of the liquid ejection head 1. The operation shown in Fig. 9 is performed for each of the multiple liquid ejection heads 1, for example.

[0124] The control unit 4 functions as the waveform defining unit 40 in each of steps S110 to S180 shown in FIG. 9 . The control unit 4 may function as the waveform defining unit 40 in step S100, or may function as a processing unit other than the waveform defining unit 40. That is, the process of step S100 may be executed by the waveform defining unit 40, or may be executed by a processing unit other than the waveform defining unit 40. In this embodiment, it is assumed that the process of step S100 is executed by the waveform defining unit 40. The process of step S100 is executed, for example, when the pressure chamber CV is filled with ink to be used by a user of the liquid ejection device 100. That is, the process of step S100 is executed after the pressure chamber CV is filled with ink to be used by the user. The process of filling the pressure chamber CV with ink may be executed by the waveform defining unit 40, or may be executed by a processing unit other than the waveform defining unit 40. The term "user" refers to a user of the liquid ejection device 100. When the manufacturer of the liquid ejection device 100 and the user are the same person, the user is also the manufacturer of the liquid ejection device 100 .

[0125] For ease of explanation, FIG. 9 assumes that the natural vibration period Tc representing the natural vibration periods of the M pressure chambers CV is the natural vibration period of one of the M pressure chambers CV.

[0126] First, in step S100, the waveform definition unit 40 causes the detection circuit 19 to detect residual vibration. For example, the waveform definition unit 40 drives the ejection unit D[m] that is the detection target for residual vibration in the drive mode for the ejection unit D that is the detection target described in Fig. 6. As a result, the detection circuit 19 detects the residual vibration of the diaphragm 14 after the piezoelectric element PZ[m] is driven, based on the detection signal Vout[m].

[0127] Next, in step S110, the waveform definition unit 40 determines the natural vibration period Tc of the pressure chamber CV based on the residual vibration detected by the detection circuit 19. For example, the waveform definition unit 40 acquires residual vibration information Vinf from the analysis unit 3, which indicates the analysis results of the residual vibration detected by the detection circuit 19. Then, the waveform definition unit 40 determines the natural vibration period Tc of the pressure chamber CV based on the residual vibration information Vinf. For example, the waveform definition unit 40 determines the natural vibration period Tc of the pressure chamber CV based on the period of the residual vibration indicated by the residual vibration information Vinf. Note that the natural vibration period Tc of the pressure chamber CV may be determined based on one or both of the amplitude and phase of the residual vibration indicated by the residual vibration information Vinf.

[0128] Next, in step S120, the waveform defining unit 40 receives execution information input by the user indicating whether or not to perform automatic correction processing, which corrects the waveform of the drive signal COMa supplied to the piezoelectric element PZ based on the correction information Cinf. For example, the waveform defining unit 40 displays an operation button, as a GUI (Graphical User Interface), on a display device (not shown) for selecting whether or not to perform automatic correction processing. The display device may be included in the liquid ejection device 100, or may be provided external to the liquid ejection device 100 so as to be able to communicate with the liquid ejection device 100. The automatic correction processing is an example of a "decision processing."

[0129] Next, in step S122, the waveform defining unit 40 determines whether or not to execute automatic correction processing based on the execution information acquired in step S120. If the result of the determination in step S122 is positive, the waveform defining unit 40 proceeds to step S130. On the other hand, if the result of the determination in step S122 is negative, the waveform defining unit 40 proceeds to step S170.

[0130] In step S130, the waveform defining section 40 acquires, from the storage unit 5, the correction information Cinf that indicates the correspondence between the natural vibration period Tc and the waveform of the drive signal COMa.

[0131] Then, in step S140, the waveform defining section 40 corrects the waveform of the drive signal COMa based on the natural vibration period Tc identified in step S110 and the correction information Cinf acquired in step S130.

[0132] Next, in step S150, the waveform defining unit 40 presents the corrected waveform of the drive signal COMa to the user. For example, the waveform defining unit 40 causes a display device to display an image showing the corrected waveform of the drive signal COMa.

[0133] Then, in step S160, the waveform defining unit 40 accepts user input of adoption information indicating whether or not to adopt the corrected waveform of the drive signal COMa. For example, the waveform defining unit 40 displays, as a GUI, an operation button on the display device for selecting whether or not to adopt the corrected waveform of the drive signal COMa. In this way, the waveform defining unit 40 accepts user input of adoption information indicating whether or not to adopt the waveform of the drive signal COMa corrected based on the natural vibration period Tc and the correction information Cinf.

[0134] Next, in step S162, the waveform defining unit 40 determines whether or not to adopt the corrected waveform of the drive signal COMa based on the adoption information acquired in step S160. If the result of the determination in step S162 is positive, the waveform defining unit 40 proceeds to step S180. On the other hand, if the result of the determination in step S162 is negative, the waveform defining unit 40 proceeds to step S170.

[0135] In step S170, the waveform defining unit 40 acquires defining information indicating the waveform of the drive signal COMa defined by the user. For example, the waveform defining unit 40 acquires the defining information by accepting the user's input of the defining information. The defining information is information for defining the waveform of the drive signal COMa to be supplied to the piezoelectric element PZ. For example, the defining information indicates the length TA1 of the waveform element Pa2 and the length TA2 of the waveform element Pa4.

[0136] Here, as described above, the process of step S170 is executed when the result of the determination in step S122 is negative, or when the result of the determination in step S162 is negative. That is, the process of step S170 is executed when the execution information indicates that automatic correction processing will not be performed, or when the adoption information indicates that the waveform of the drive signal COMa corrected based on the natural vibration period Tc and the correction information Cinf will not be adopted. In this way, in this embodiment, the user can select whether to correct the waveform of the drive signal COMa through automatic correction processing or to manually correct the waveform of the drive signal COMa. As a result, in this embodiment, the usability of the liquid ejection device 100 can be improved.

[0137] After executing the process of step S170, the waveform defining section 40 proceeds to step S180. That is, the process of step S180 is executed when the result of the determination in step S162 is negative or when the process of step S170 has been executed.

[0138] In step S180, the waveform defining unit 40 determines the waveform of the drive signal COMa to be supplied to the piezoelectric element PZ. For example, if the process of step S170 has been executed, the waveform defining unit 40 determines the waveform of the drive signal COMa based on the defining information acquired in step S170. In this case, the waveform of the drive signal COMa is determined to be the waveform defined by the user. For example, if the process of step S180 is executed after the process of step S170 has been executed, the length TA1 of the waveform element Pa2 and the length TA2 of the waveform element Pa4 can each be set to a length desired by the user.

[0139] Furthermore, in step S180, which is executed when the result of the determination in step S162 is negative, for example, the waveform defining unit 40 determines the waveform of the drive signal COMa corrected in step S140 as the waveform of the drive signal COMa to be supplied to the piezoelectric element PZ. In this manner, the waveform defining unit 40 determines the waveform of the drive signal COMa to be supplied to the piezoelectric element PZ based on the natural vibration period Tc identified based on the residual vibration and the correction information Cinf. In this embodiment, by adopting the waveform of the drive signal COMa corrected by the automatic correction process, the waveform of the drive signal COM that drives the piezoelectric element PZ can be appropriately and easily determined.

[0140] Note that the operation of the liquid ejection device 100 when determining the waveform of the drive signal COMa is not limited to the example shown in Fig. 9. For example, the natural vibration period Tc representing the natural vibration periods of the M pressure chambers CV may be statistically determined using the natural vibration periods of the K pressure chambers CV. In this case, the waveform definition unit 40, for example, sequentially drives K ejection units D corresponding to the K pressure chambers CV in the drive mode as the ejection unit D to be detected described in Fig. 6.

[0141] Also, for example, the series of processes in steps S120 and S122 may be omitted. Also, for example, the series of processes in steps S120 and S122 and the process of step S170 may be omitted. In an aspect in which the series of processes in steps S120 and S122 and the process of step S170 are omitted, if the result of the determination in step S162 is negative, the waveform defining section 40 may end the operation shown in Fig. 9 without correcting the waveform of the drive signal COMa. Also, for example, the series of processes in steps S120 and S122, the series of processes in steps S160 and S162, and the process of step S170 may be omitted.

[0142] Furthermore, for example, the waveform of the drive signal COMa may be determined without using the reference waveform of the pulse PA. In this case, for example, in step S130, information indicating the waveform of the pulse PA for each division of the natural vibration period Tc of the pressure chamber CV may be acquired as waveform information. Then, in step S140, the waveform of the drive signal COMa may be determined based on the natural vibration period Tc and the above-mentioned waveform information.

[0143] As described above, in this embodiment, the liquid ejection device 100 includes a liquid ejection head 1 and a waveform defining unit 40. The liquid ejection head 1 includes a nozzle N, a piezoelectric element PZ that is driven by a drive signal COMa, a diaphragm 14 that vibrates when the piezoelectric element PZ is driven, a pressure chamber CV that is filled with ink and to which pressure for ejecting ink from the nozzle N is applied by the vibration of the diaphragm 14, and a detection circuit 19 that detects residual vibration of the diaphragm 14 after the piezoelectric element PZ is driven. The waveform defining unit 40 determines the natural vibration period Tc of the pressure chamber CV based on the residual vibration detected by the detection circuit 19, acquires waveform information from the storage unit 5 indicating the correspondence between the natural vibration period Tc and the waveform of the drive signal COMa, and determines the waveform of the drive signal COMa to be supplied to the piezoelectric element PZ based on the natural vibration period Tc determined based on the residual vibration and the waveform information acquired from the storage unit 5. For example, the control program PG of the liquid ejection device 100 causes the control unit 4 to function as the waveform defining unit 40. In this embodiment, the correction information Cinf corresponds to waveform information.

[0144] As described above, in this embodiment, the waveform defining unit 40 determines the waveform of the drive signal COMa based on the correction information Cinf prepared in advance and the natural vibration period Tc determined based on the residual vibration detected by the detection circuit 19. In this embodiment, the natural vibration period Tc determined based on the residual vibration detected by the detection circuit 19 is used to determine the waveform of the drive signal COMa, so the waveform of the drive signal COMa can be appropriately determined depending on the usage conditions of the liquid ejection device 100. Furthermore, in this embodiment, the correction information Cinf prepared in advance is used to determine the waveform of the drive signal COMa, so the waveform of the drive signal COMa can be easily determined. Therefore, in this embodiment, the waveform of the drive signal COMa that drives the piezoelectric element PZ can be appropriately and easily determined.

[0145] Furthermore, in this embodiment, the waveform defining section 40 determines the natural vibration period Tc based on the period of the residual vibration detected by the detection circuit 19. In this case, the natural vibration period Tc can be easily determined.

[0146] Furthermore, in this embodiment, the waveform defining unit 40 accepts user input of execution information indicating whether to perform automatic correction processing, which determines the waveform of the drive signal COMa to be supplied to the piezoelectric element PZ based on the correction information Cinf. If the execution information indicates that automatic correction processing will not be performed, the waveform defining unit 40 further accepts user input of definition information for defining the waveform of the drive signal COMa to be supplied to the piezoelectric element PZ. In this case, the user can select whether to determine the waveform of the drive signal COMa through automatic correction processing or to manually determine the waveform of the drive signal COMa. As a result, the usability of the liquid ejection device 100 can be improved.

[0147] In this embodiment, the waveform definition unit 40 also accepts user input of adoption information indicating whether to adopt the waveform of the drive signal COMa determined based on the natural vibration period Tc and the correction information Cinf. If the adoption information indicates that the waveform of the drive signal COMa determined based on the natural vibration period Tc and the correction information Cinf should not be adopted, the waveform definition unit 40 further accepts user input of definition information for defining the waveform of the drive signal COMa to be supplied to the piezoelectric element PZ. In this case, the user can select whether to adopt the waveform of the drive signal COMa determined by the automatic correction process or to manually determine the waveform of the drive signal COMa. This improves the usability of the liquid ejection device 100.

[0148] Furthermore, in this embodiment, the correction information Cinf indicates the correspondence between the waveform of the drive signal COMa and the natural vibration period Tc identified based on the residual vibration detected when the pressure chamber CV is filled with ink before shipping the liquid ejection head 1. In this case, regardless of the type of ink to be used in the liquid ejection head 1 after shipping, the correction information Cinf can be prepared using a specific ink before shipping the liquid ejection head 1.

[0149] [2. Modifications] Each of the above embodiments can be modified in various ways. Specific modified embodiments are exemplified below. Two or more embodiments arbitrarily selected from the following examples can be combined as appropriate within a range that does not contradict each other. In the modified examples exemplified below, elements whose actions and functions are equivalent to those of the embodiments will be designated by the same reference numerals as in the above description, and detailed descriptions of each will be omitted as appropriate.

[0150] [First Modification] In the above-described embodiment, a case has been exemplified in which one piece of correction information Cinf is prepared for each liquid ejection head 1, but the present invention is not limited to this. For example, a plurality of pieces of correction information Cinf may be prepared for each liquid ejection head 1.

[0151] FIG. 10 is a diagram showing an example of the waveform of the residual vibration signal Vd according to the first modified example. FIG. 10 schematically shows an example of the waveform of the residual vibration signal Vd corresponding to each of three types of ink of the same color. The vertical axis of the diagram represents the potential of the residual vibration signal Vd, and the horizontal axis represents time. For example, the residual vibration signal Vd1 is a residual vibration signal Vd that indicates the residual vibration detected when the pressure chamber CV is filled with the first ink. The residual vibration signal Vd2 is a residual vibration signal Vd that indicates the residual vibration detected when the pressure chamber CV is filled with the second ink. Furthermore, the residual vibration signal Vd3 is a residual vibration signal Vd that indicates the residual vibration detected when the pressure chamber CV is filled with the third ink.

[0152] In the example shown in Figure 10, the periods of the residual vibration signal Vd1, Vd2, and Vd3 are all the same. In this case, the natural vibration period Tc determined based on the period of the residual vibration signal Vd1, the natural vibration period Tc determined based on the period of the residual vibration signal Vd2, and the natural vibration period Tc determined based on the period of the residual vibration signal Vd3 are all the same. Even if the natural vibration periods Tc corresponding to the three types of ink are all the same, as shown in Figure 10, the behavior of the residual vibration remaining in the ink in the pressure chamber CV of the ejection section D differs for each of the three types of ink. For example, of the amplitude λc1 of the residual vibration signal Vd1, the amplitude λc2 of the residual vibration signal Vd2, and the amplitude λc3 of the residual vibration signal Vd3, the amplitude λc1 of the residual vibration signal Vd1 is the largest and the amplitude λc3 of the residual vibration signal Vd3 is the smallest.

[0153] Because the behavior of the residual vibration remaining in the ink in the pressure chamber CV of the ejection section D differs for each of the three types of ink, it is thought that the appropriate waveform of the drive signal COMa that drives the ejection section D also differs for each of the three types of ink. For this reason, in this modified example, the ink used in the liquid ejection head 1 is classified based on the amplitude λc of the residual vibration signal Vd, i.e., the amplitude of the residual vibration. Below, it is assumed that the ink used in the liquid ejection head 1 is classified into one of ink whose amplitude λc is smaller than a threshold amplitude λ1, ink whose amplitude λc is equal to or greater than the threshold amplitude λ1 and smaller than a threshold amplitude λ2, and ink whose amplitude λc is equal to or greater than the threshold amplitude λ2.

[0154] In the example shown in FIG. 10, the first ink is classified as an ink whose amplitude λc is equal to or greater than the threshold amplitude λ2 because the amplitude λc1 of the residual vibration signal Vd1 is equal to or greater than the threshold amplitude λ2. The third ink is classified as an ink whose amplitude λc is smaller than the threshold amplitude λ1 because the amplitude λc3 of the residual vibration signal Vd3 is smaller than the threshold amplitude λ1. The second ink is classified as an ink whose amplitude λc is equal to or greater than the threshold amplitude λ1 but smaller than the threshold amplitude λ2 because the amplitude λc2 of the residual vibration signal Vd2 is equal to or greater than the threshold amplitude λ1 but smaller than the threshold amplitude λ2. The number of ink classifications is not limited to three. For example, the number of ink classifications may be two, four, or more.

[0155] Furthermore, the magnitude relationship of the amplitude λc of the residual vibration signal Vd corresponding to the first ink, second ink, and third ink is not limited to the example shown in Fig. 10. The amplitude of the residual vibration signal Vd is not limited to the amplitude λc of the peak VPm1 at which the waveform of the residual vibration signal Vd first reaches a valley, as explained in Fig. 7. Therefore, the amplitude of the residual vibration signal Vd used to classify the inks is also not limited to the amplitude λc of the peak VPm1 at which the waveform of the residual vibration signal Vd first reaches a valley.

[0156] In this modification, as shown in FIG. 11, correction information Cinf is prepared for each of a plurality of ink divisions.

[0157] In the above-described embodiment, the same correction value was used if the natural vibration period Tc was the same, so the same correction value was applied to these three types of ink. As shown in FIG. 10, the periods of the residual vibration signals Vd1, Vd2, and Vd3 are the same for the three types of ink, and therefore the natural vibration period Tc is also specified to be the same value. However, as can be seen from the fact that the amplitudes λc1, λc2, and λc3 of the residual vibration signals Vd1, Vd2, and Vd3 are different from one another, the appropriate waveform of the drive signal COMa should differ between the three types of ink. Therefore, in this modified example, the correction value is also varied depending on the amplitude.

[0158] Fig. 11 is an explanatory diagram for explaining the correction information Cinf according to the first modified example. Fig. 11 shows an example of the correction information Cinf corresponding to one of the plurality of liquid ejection heads 1. In this modified example, as described above, correction information Cinf is prepared for each of the plurality of ink divisions.

[0159] The correction information Cinf shown in FIG. 11 includes correction information Cinf1, correction information Cinf2, and correction information Cinf3, which respectively correspond to three ink classifications. Hereinafter, the correction information Cinf1, Cinf2, and Cinf3 are also referred to as multiple pieces of correction information Cinf. The correction information Cinf1, Cinf2, and Cinf3 are examples of "multiple pieces of corresponding information." Each of the correction information Cinf1, Cinf2, and Cinf3 is the same as the correction information Cinf described in FIG. 8, except for the correction value. For example, in this modification, it is assumed that each of the correction information Cinf1, Cinf2, and Cinf3 indicates a correspondence relationship between the waveform of the drive signal COMa and the natural vibration period Tc identified based on residual vibration detected when the pressure chamber CV is filled with ink before shipping the liquid ejection head 1.

[0160] For example, correction information Cinf1 is correction information Cinf corresponding to ink in which the amplitude λc of the residual vibration signal Vd is equal to or greater than the threshold amplitude λ2. With correction information Cinf1, if the natural vibration period Tc of pressure chamber CV is smaller than threshold Tth1, the correction value for length TA1 is 0.95 and the correction value for length TA2 is 0.85. Also, if the natural vibration period Tc of pressure chamber CV is equal to or greater than threshold Tth1 and equal to or less than threshold Tth2, the correction values for length TA1 and length TA2 are both 1.0. Also, if the natural vibration period Tc of pressure chamber CV is greater than threshold Tth2, the correction value for length TA1 is 1.25 and the correction value for length TA2 is 1.15.

[0161] Furthermore, for example, the correction information Cinf2 is correction information Cinf corresponding to ink in which the amplitude λc of the residual vibration signal Vd is equal to or greater than the threshold amplitude λ1 and smaller than the threshold amplitude λ2. With the correction information Cinf2, when the natural vibration period Tc of the pressure chamber CV is smaller than the threshold Tth1, the correction value for the length TA1 is 0.9 and the correction value for the length TA2 is 0.8. When the natural vibration period Tc of the pressure chamber CV is equal to or greater than the threshold Tth1 and smaller than the threshold Tth2, the correction value for the length TA1 and the correction value for the length TA2 are both 1.0. When the natural vibration period Tc of the pressure chamber CV is greater than the threshold Tth2, the correction value for the length TA1 is 1.2 and the correction value for the length TA2 is 1.1.

[0162] Furthermore, for example, correction information Cinf3 is correction information Cinf corresponding to ink in which the amplitude λc of the residual vibration signal Vd is smaller than the threshold amplitude λ1. With correction information Cinf3, when the natural vibration period Tc of pressure chamber CV is smaller than threshold Tth1, the correction value for length TA1 is 0.85 and the correction value for length TA2 is 0.75. When the natural vibration period Tc of pressure chamber CV is equal to or greater than threshold Tth1 and equal to or smaller than threshold Tth2, the correction values for length TA1 and length TA2 are both 1.0. When the natural vibration period Tc of pressure chamber CV is greater than threshold Tth2, the correction value for length TA1 is 1.15 and the correction value for length TA2 is 1.05.

[0163] In the example shown in Figure 11, the waveform of the drive signal COMa is corrected so that the ink having a large amplitude λc of the residual vibration signal Vd has a higher vibration damping ability to attenuate the residual vibration of the ejection section D than the ink having a small amplitude λc of the residual vibration signal Vd.

[0164] The content of the correction information Cinf is not limited to the example shown in Fig. 11. For example, the correction value of the length TA1 and the correction value of the length TA2 may be values other than the example values shown in Fig. 11.

[0165] Next, the operation of the liquid ejection device 100 according to this modified example will be described with reference to FIG.

[0166] 12 is a flowchart showing an example of the operation of the liquid ejection device 100 according to the first modified example. FIG. 12 shows an example of the operation of the liquid ejection device 100 when determining the waveform of the drive signal COMa. The operation shown in FIG. 12 is performed, for example, for each of the multiple liquid ejection heads 1. The operation shown in FIG. 12 is similar to the operation shown in FIG. 9 except that the process of step S130A is performed instead of the process of step S130 shown in FIG. 9. A detailed description of processes similar to those described in FIG. 9 will be omitted. The timing at which the operation shown in FIG. 12 is performed is similar to the timing at which the operation shown in FIG. 9 is performed, for example.

[0167] The processing from step S110 to step S122 is the same as the operation shown in FIG. 9, except that if the result of the determination in step S122 is positive, the processing proceeds to step S130.

[0168] For example, in step S130A, the control unit 4 functions as the waveform defining unit 40 and acquires specific correction information Cinf from the storage unit 5. For example, the waveform defining unit 40 identifies one of the multiple pieces of correction information Cinf as the specific correction information Cinf based on the residual vibration detected by the detection circuit 19. Specifically, the waveform defining unit 40 acquires the specific correction information Cinf from the storage unit 5 based on the amplitude λc of the residual vibration signal Vd. For example, if the amplitude λc of the residual vibration signal Vd indicated by the residual vibration information Vinf is smaller than the threshold amplitude λ1, the waveform defining unit 40 acquires correction information Cinf3 as the specific correction information Cinf. Furthermore, for example, if the amplitude λc of the residual vibration signal Vd indicated by the residual vibration information Vinf is equal to or greater than the threshold amplitude λ1 and smaller than the threshold amplitude λ2, the waveform defining unit 40 acquires correction information Cinf2 as the specific correction information Cinf. Furthermore, for example, when the amplitude λc of the residual vibration signal Vd indicated by the residual vibration information Vinf is equal to or greater than the threshold amplitude λ2, the waveform defining section 40 acquires the correction information Cinf1 as the specific correction information Cinf.

[0169] As a result, in this modified example, the correction information Cinf suitable for the type of ink used in the liquid ejection head 1 can be used to determine the waveform of the drive signal COMa. As a result, in this modified example, it is possible to prevent limitations on the type of ink for which the waveform of the drive signal COMa can be appropriately determined.

[0170] As described above, in this modification, the waveform defining unit 40 identifies one of the plurality of pieces of correction information Cinf as the specific correction information Cinf based on the amplitude of the residual vibration detected by the detection circuit 19. Note that in step S130A, the waveform defining unit 40 may acquire the plurality of pieces of correction information Cinf from the storage unit 5 and identify one of the acquired plurality of pieces of correction information Cinf as the specific correction information Cinf. The specific correction information Cinf is an example of "waveform information."

[0171] After executing the process of step S130A, the waveform defining section 40 moves the process to step S140. The process from step S140 onwards is the same as the operation shown in FIG.

[0172] The operation of the liquid ejection device 100 when determining the waveform of the drive signal COMa is not limited to the example shown in FIG. 12. The modified embodiment described in FIG. 9 can also be adopted in the operation of the liquid ejection device 100 according to this modified example. Furthermore, the information used to identify the specific correction information Cinf is not limited to the amplitude of the residual vibration. For example, the waveform definition unit 40 may identify one of the multiple pieces of correction information Cinf as the specific correction information Cinf based on the phase of the residual vibration detected by the detection circuit 19.

[0173] As described above, in this modification, the storage unit 5 stores a plurality of pieces of correction information Cinf each indicating a plurality of correspondence relationships in which the waveform of the drive signal COMa corresponding to the natural vibration period Tc differs from one another. The waveform definition unit 40 identifies one of the plurality of pieces of correction information Cinf as specific correction information Cinf based on the residual vibration detected by the detection circuit 19. For example, the waveform definition unit 40 identifies one of the plurality of pieces of correction information Cinf as specific correction information Cinf based on the amplitude of the residual vibration detected by the detection circuit 19.

[0174] In this manner, in this modified example, multiple pieces of correction information Cinf indicating multiple correspondence relationships in which the waveform of the drive signal COMa corresponding to the natural vibration period Tc differs from one another are prepared for one liquid ejection head 1. Therefore, in this modified example, in addition to the same effects as the above-described embodiment, it is possible to obtain the effect of suppressing limitations on the type of ink for which the waveform of the drive signal COMa is appropriately determined.

[0175] [Second Modification] In the above-described embodiment and first modified example, the memory in which the correction information Cinf is stored may be provided in the liquid ejection head 1. For example, the storage unit 5 in which the control program PG and the correction information Cinf are stored may be provided in the liquid ejection head 1. Alternatively, if the correction information Cinf is stored in a memory separate from the storage unit 5 in which the control program PG is stored, the memory in which the correction information Cinf is stored may be provided in the liquid ejection head 1. The storage unit 5 or memory in which the correction information Cinf is stored is an example of a "storage section." In this case, the manufacturer of the liquid ejection head 1 stores the correction information Cinf in advance in the storage unit 5 of the liquid ejection head 1 when manufacturing the liquid ejection head 1. The user reads out the correction information Cinf stored by the manufacturer of the liquid ejection head 1 in step S130.

[0176] As described above, this modification can also achieve the same effects as the above-described embodiment. Furthermore, in this modification, the storage unit 5 or memory in which the correction information Cinf is stored is provided in the liquid ejection head 1, so that it is possible to prevent the management of the correction information Cinf corresponding to the liquid ejection head 1 from becoming complicated. For example, it is possible to prevent correction information Cinf corresponding to a liquid ejection head 1 other than the one liquid ejection head 1 from being used for the one liquid ejection head 1.

[0177] [Third Modification] In the above-described embodiment and first modified example, the memory storing the correction information Cinf may be provided in an external device communicatively connected to the liquid ejection apparatus 100. For example, the storage unit 5 storing the control program PG and the correction information Cinf may be provided in an external device communicatively connected to the liquid ejection apparatus 100. Alternatively, if the correction information Cinf is stored in a memory separate from the storage unit 5 storing the control program PG, the memory storing the correction information Cinf may be provided in an external device communicatively connected to the liquid ejection apparatus 100. The storage unit 5 or memory storing the correction information Cinf is an example of a "storage unit." The external device referred to here does not refer to a device managed by the user, but rather to a device managed by the manufacturer of the liquid ejection head 1. In other words, the correction information Cinf is stored in a device managed by the manufacturer of the liquid ejection head 1, and in step S130, the liquid ejection apparatus 100 connects to the device managed by the manufacturer of the liquid ejection head 1 and reads out the correction information Cinf.

[0178] As described above, this modification can also achieve the same effects as the above-described embodiment. Furthermore, in this modification, the storage unit 5 or memory in which the correction information Cinf is stored is provided in an external device that is communicably connected to the liquid ejection device 100. Therefore, in this modification, the correction information Cinf can be easily updated.

[0179] [Third Modification] In the above-described embodiment and modified example, one piezoelectric element PZ, one pressure chamber CV, and one nozzle N are provided for one discharge portion D, but the present invention is not limited to this. For example, one discharge portion D may have two piezoelectric elements PZ, two pressure chambers CV, and one nozzle N. As described above, in this modified example, the same effects as those of the above-described embodiment and modified example can be obtained.

[0180] [Fourth Modification] In the above-described embodiment and modified example, a serial-type liquid ejection device 100 in which a carriage 91 carrying a liquid ejection head 1 is reciprocated in the X-axis direction is illustrated, but the present invention is not limited to such an embodiment. For example, the liquid ejection device 100 may be a line-type liquid ejection device in which multiple nozzles N are distributed across the entire width of the medium PP. As described above, this modified example can also achieve the same effects as the above-described embodiment and modified example.

[0181] [Fifth Modification] The liquid ejection device 100 exemplified in the above-described embodiment and modified example can be employed in various devices such as facsimile machines and copiers, as well as devices dedicated to printing. However, the use of the liquid ejection device of the present invention is not limited to printing. For example, a liquid ejection device that ejects a solution of a color material is used as a manufacturing device for forming color filters for liquid crystal display devices. Furthermore, a liquid ejection device that ejects a solution of a conductive material is used as a manufacturing device for forming wiring and electrodes for wiring boards. As described above, this modified example can also achieve the same effects as the above-described embodiment and modified example.

[0182] [3. Notes] From the above-described exemplary embodiments, the following configurations can be understood, for example.

[0183] A liquid ejection device according to aspect 1, which is a preferred aspect, comprises a liquid ejection head and a control unit, wherein the liquid ejection head has a nozzle, a piezoelectric element that is driven by a drive signal supplied thereto, a vibration plate that vibrates when the piezoelectric element is driven, a pressure chamber that is filled with liquid and to which pressure for ejecting liquid from the nozzle is applied by the vibration of the vibration plate, and a detection unit that detects residual vibration of the vibration plate after the piezoelectric element is driven, and the control unit identifies the natural vibration period of the pressure chamber based on the residual vibration detected by the detection unit, acquires waveform information from a memory unit that indicates the correspondence between the natural vibration period and the waveform of the drive signal, and determines the waveform of the drive signal to be supplied to the piezoelectric element based on the natural vibration period identified based on the residual vibration and the waveform information acquired from the memory unit. According to the first aspect, the waveform of the drive signal that drives the piezoelectric element can be determined appropriately and easily.

[0184] In the liquid ejection device according to Aspect 2, which is a specific example of Aspect 1, the control unit identifies the natural vibration period based on the period of the residual vibration detected by the detection unit. According to the second aspect, the natural vibration period can be easily identified.

[0185] In a liquid ejection device according to aspect 3, which is a specific example of aspect 1 or aspect 2, the memory unit stores a plurality of correspondence information pieces each indicating a plurality of correspondence relationships in which the waveforms of the drive signal corresponding to the natural vibration period are different from each other, and the control unit identifies one of the plurality of correspondence information pieces as the waveform information based on the residual vibration detected by the detection unit. According to the third aspect, it is possible to prevent limitations on the types of liquid for which the waveform of the drive signal can be appropriately determined.

[0186] In a liquid ejection device according to aspect 4, which is a specific example of aspect 3, the control unit identifies one of the plurality of corresponding information as the waveform information based on the amplitude of the residual vibration detected by the detection unit. Also in the fourth aspect, it is possible to prevent limitations on the type of liquid for which the waveform of the drive signal can be appropriately determined. Furthermore, in the fourth aspect, it is possible to easily identify the waveform information from a plurality of pieces of correspondence information.

[0187] In a liquid ejection device according to aspect 5, which is a specific example of any one of aspects 1 to 4, the control unit accepts user input of execution information indicating whether or not to perform a decision process to determine the waveform of the drive signal to be supplied to the piezoelectric element based on the waveform information, and if the execution information indicates that the decision process will not be performed, further accepts user input of specification information to specify the waveform of the drive signal to be supplied to the piezoelectric element. According to the fifth aspect, the usability of the liquid ejection device can be improved.

[0188] In a liquid ejection device according to aspect 6, which is a specific example of any one of aspects 1 to 5, the control unit accepts user input of adoption information indicating whether or not to adopt the waveform of the drive signal determined based on the natural vibration period and the waveform information, and if the adoption information indicates that the waveform of the drive signal determined based on the natural vibration period and the waveform information will not be adopted, further accepts user input of specification information for specifying the waveform of the drive signal to be supplied to the piezoelectric element. In the sixth aspect as well, the usability of the liquid ejection device can be improved.

[0189] In a liquid ejection device according to Aspect 7, which is a specific example of any one of Aspects 1 to 6, the storage unit is provided in the liquid ejection head. According to the seventh aspect, it is possible to prevent the management of waveform information corresponding to the liquid ejection head from becoming complicated.

[0190] In a liquid ejection device according to aspect 8, which is a specific example of any one of aspects 1 to 6, the memory unit is provided in an external device that is communicatively connected to the liquid ejection device. According to the eighth aspect, the waveform information can be easily updated.

[0191] In a liquid ejection device according to aspect 9, which is a specific example of any one of aspects 1 to 8, the waveform information indicates the correspondence between the natural vibration period identified based on the residual vibration detected when the pressure chamber is filled with liquid before shipping the liquid ejection head, and the waveform of the drive signal. According to the ninth aspect, waveform information can be prepared using a specific liquid before shipping the liquid ejection head, regardless of the type of liquid that will be used in the liquid ejection head after shipping.

[0192] Furthermore, a control method for a liquid ejection device according to a preferred aspect 10 is a control method for a liquid ejection device having a liquid ejection head including a nozzle, a piezoelectric element that is driven by the supply of a drive signal, a vibration plate that vibrates when the piezoelectric element is driven, a pressure chamber filled with liquid and in which pressure for ejecting liquid from the nozzle is applied by the vibration of the vibration plate, and a detection unit that detects residual vibration of the vibration plate after the piezoelectric element is driven, wherein the natural vibration period of the pressure chamber is identified based on the residual vibration detected by the detection unit, waveform information indicating the correspondence between the natural vibration period and the waveform of the drive signal is obtained from a memory unit, and the waveform of the drive signal to be supplied to the piezoelectric element is determined based on the natural vibration period identified based on the residual vibration and the waveform information obtained from the memory unit. According to the tenth aspect, the waveform of the drive signal for driving the piezoelectric element can be determined appropriately and easily.

[0193] Furthermore, a control program for a liquid ejection device according to a preferred embodiment, aspect 11, is a control program for a liquid ejection device having a liquid ejection head including a nozzle, a piezoelectric element that is driven by the supply of a drive signal, a vibration plate that vibrates when the piezoelectric element is driven, a pressure chamber filled with liquid and to which pressure for ejecting liquid from the nozzle is applied by the vibration of the vibration plate, and a detection unit that detects residual vibration of the vibration plate after the piezoelectric element is driven, and causes a computer to function as a control unit that identifies the natural vibration period of the pressure chamber based on the residual vibration detected by the detection unit, acquires waveform information from a memory unit that indicates the correspondence between the natural vibration period and the waveform of the drive signal, and determines the waveform of the drive signal to be supplied to the piezoelectric element based on the natural vibration period identified based on the residual vibration and the waveform information acquired from the memory unit. According to the eleventh aspect, the waveform of the drive signal for driving the piezoelectric element can be determined appropriately and easily. [Explanation of symbols]

[0194] 1...liquid ejection head, 2...drive signal generation unit, 3...analysis unit, 4...control unit, 5...storage unit, 7...maintenance unit, 8...medium transport mechanism, 9...carriage transport mechanism, 10...recording head, 18...switching circuit, 19...detection circuit, 40...waveform determination unit, 60...ink container, 100...liquid ejection device, CV...pressure chamber, D...ejection unit, N...nozzle, PP...medium, PZ...piezoelectric element.

Claims

1. A liquid ejection head and a control unit are provided, The liquid ejection head includes: A nozzle; a piezoelectric element that is driven by a drive signal; a vibration plate that vibrates when driven by the piezoelectric element; a pressure chamber filled with liquid, and pressure for discharging the liquid from the nozzle is applied by vibration of the vibration plate; a detection unit that detects residual vibration of the diaphragm after the piezoelectric element is driven; and The control unit determining a natural vibration period of the pressure chamber based on the residual vibration detected by the detection unit; acquiring waveform information indicating a correspondence relationship between the natural vibration period and the waveform of the drive signal from a storage unit; determining a waveform of the drive signal to be supplied to the piezoelectric element based on the natural vibration period identified based on the residual vibration and the waveform information acquired from the storage unit; A liquid ejection device characterized by:

2. The control unit determining the natural vibration period based on the period of the residual vibration detected by the detection unit; The liquid ejection device according to claim 1 .

3. the storage unit stores a plurality of pieces of correspondence information indicating a plurality of correspondence relationships in which waveforms of the drive signals corresponding to the natural vibration periods are different from one another, The control unit identifying one of the plurality of pieces of correspondence information as the waveform information based on the residual vibration detected by the detection unit; The liquid ejection device according to claim 1 .

4. The control unit identifying one of the plurality of pieces of correspondence information as the waveform information based on the amplitude of the residual vibration detected by the detection unit; 4. The liquid ejection device according to claim 3.

5. The control unit receiving a user input of execution information indicating whether or not to perform a determination process for determining the waveform of the drive signal to be supplied to the piezoelectric element based on the waveform information; If the execution information indicates that the determination process is not to be performed, further receiving input of definition information by the user for defining a waveform of the drive signal to be supplied to the piezoelectric element. The liquid ejection device according to claim 1 .

6. The control unit receiving, from a user, input of adoption information indicating whether or not to adopt the waveform of the drive signal determined based on the natural vibration period and the waveform information; If the adoption information indicates that the waveform of the drive signal determined based on the natural vibration period and the waveform information is not adopted, an input of definition information by the user for defining the waveform of the drive signal to be supplied to the piezoelectric element is further accepted. The liquid ejection device according to claim 1 .

7. the storage unit is provided in the liquid ejection head; The liquid ejection device according to claim 1 .

8. the storage unit is provided in an external device communicably connected to the liquid ejection device; The liquid ejection device according to claim 1 .

9. The waveform information is a waveform of the drive signal, the waveform of the drive signal being a waveform of the liquid ejection head; The liquid ejection device according to claim 1 .

10. A nozzle; a piezoelectric element that is driven by a drive signal; a vibration plate that vibrates when driven by the piezoelectric element; a pressure chamber filled with liquid, and pressure for discharging the liquid from the nozzle is applied by vibration of the vibration plate; a detection unit that detects residual vibration of the diaphragm after the piezoelectric element is driven; A method for controlling a liquid ejection device equipped with a liquid ejection head including: determining a natural vibration period of the pressure chamber based on the residual vibration detected by the detection unit; acquiring waveform information indicating a correspondence relationship between the natural vibration period and the waveform of the drive signal from a storage unit; determining a waveform of the drive signal to be supplied to the piezoelectric element based on the natural vibration period identified based on the residual vibration and the waveform information acquired from the storage unit; A method for controlling a liquid ejection device.

11. A nozzle; a piezoelectric element that is driven by a drive signal; a vibration plate that vibrates when driven by the piezoelectric element; a pressure chamber filled with liquid, and pressure for discharging the liquid from the nozzle is applied by vibration of the vibration plate; a detection unit that detects residual vibration of the diaphragm after the piezoelectric element is driven; A control program for a liquid ejection device including a liquid ejection head, Computer, determining a natural vibration period of the pressure chamber based on the residual vibration detected by the detection unit; acquiring waveform information indicating a correspondence relationship between the natural vibration period and the waveform of the drive signal from a storage unit; determining a waveform of the drive signal to be supplied to the piezoelectric element based on the natural vibration period identified based on the residual vibration and the waveform information acquired from the storage unit; Functioning as a control unit, A control program for a liquid ejection device.

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