Liquid ejection apparatus and method for driving liquid ejection apparatus

Abstract

The invention provides a liquid ejecting apparatus and a driving method of the liquid ejecting apparatus. The liquid ejecting apparatus includes: a liquid ejecting head including a first ejecting portion including a first nozzle, a first pressure chamber, and a first driving element; a first drive signal generation circuit that generates a first drive signal having a first pulse supplied to the first drive element when a first amount of liquid droplets are ejected from the first nozzle; and a second drive signal generation circuit that generates a second drive signal that is supplied to the first drive element and has a second pulse different from the first pulse, the first drive signal having a first start potential holding element that holds the first potential from the start of the one drive cycle to the start of the first pulse, and the second drive signal having a second start potential holding element that holds the first potential from the start of the one drive cycle to the start of the first pulse. The second drive signal has a second start potential holding element for holding a second potential from the start of the one drive cycle to the start of the second pulse, and the first potential is different from the second potential.

Description

Technical Field

[0001] The present disclosure relates to a liquid ejecting device and a driving method of the liquid ejecting device. Background Art

[0002] Conventionally, there has been proposed a liquid ejecting device for ejecting liquid such as ink onto a medium such as printing paper.

[0003] The liquid ejection device described in Patent Document 1 includes a drive signal generator that generates a drive signal; a drive pulse selector that selectively combines multiple drive pulses included in the drive signal; and a drive element that ejects liquid droplets from a nozzle based on the selected drive pulses. This device selects pulses corresponding to the image to be printed from the multiple types of pulses included in the drive signal, and changes the amount of liquid droplets ejected from the nozzle.

[0004] The drive signal maintains a common potential during periods other than pulses. Designing the pulse shape to meet the discharge volume and discharge speed required by the pulses included in the drive signal while maintaining a fixed common potential limits design freedom. Consequently, for example, achieving the desired droplet discharge volume is difficult, and correction of the discharge volume is inadequate.

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-88582 Summary of the Invention

[0006] A liquid ejection device according to one embodiment of the present disclosure comprises: a liquid ejection head comprising a first ejection portion, the first ejection portion including a first nozzle for ejecting liquid, a first pressure chamber connected to the first nozzle, and a first drive element driven in a manner that changes the volume of the first pressure chamber according to a drive signal; a first drive signal generating circuit that generates a first drive signal having a first pulse and supplied to the first drive element when ejecting a first amount of liquid droplets from the first nozzle; and a second drive signal generating circuit that generates a second drive signal having a second pulse different from the first pulse and supplied to the first drive element, the first drive signal having a first starting potential maintaining element that maintains a first potential from the start of a drive cycle to the start of the first pulse, and the second drive signal having a second starting potential maintaining element that maintains a second potential from the start of a drive cycle to the start of the second pulse, the first potential being different from the second potential.

[0007] In a driving method for a liquid ejection device involved in one embodiment of the present disclosure, the liquid ejection device includes a liquid ejection head, the liquid ejection head includes a first ejection part, the first ejection part includes a first nozzle for ejecting liquid, a first pressure chamber connected to the first nozzle, and a first driving element driven in a manner that changes the volume of the first pressure chamber according to a driving signal. In the driving method of the liquid ejection device, when a first amount of droplets is ejected from the first nozzle, a first driving signal having a first pulse is generated and supplied to the first driving element, and a second driving signal having a second pulse different from the first pulse is generated and supplied to the first driving element. When the first driving signal and the second driving signal are generated, a first potential of a first starting potential holding element of the first driving signal from the beginning of a driving cycle to the beginning of the first pulse is set to be different from a second potential of a second starting potential holding element of the second driving signal from the beginning of a driving cycle to the beginning of the second pulse. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic diagram showing a configuration example of the liquid ejecting device according to the first embodiment.

[0009] Figure 2 It is a diagram showing the electrical configuration of the liquid ejecting device according to the first embodiment.

[0010] Figure 3 for Figure 2 A bottom view of the liquid ejection head is shown.

[0011] Figure 4 To express Figure 3 A cross-sectional view of a portion of a head chip is shown.

[0012] Figure 5 For use in opposite Figure 3 FIG. 1 is a diagram illustrating a driving signal supplied to the first nozzle array.

[0013] Figure 6 For use in opposite Figure 3 FIG. 1 is a diagram illustrating a driving signal supplied to the second nozzle array.

[0014] Figure 7 For use in opposite Figure 3 FIG. 1 is a diagram illustrating a driving signal supplied to the third nozzle array.

[0015] Figure 8 1 and 2 are diagrams showing an example in which the driving cycle is continuous.

[0016] Figure 9A diagram for explaining the supply of a driving signal.

[0017] Figure 10 A diagram for explaining the supply of a driving signal.

[0018] Figure 11 A diagram for explaining conventional correction of a drive signal.

[0019] Figure 12 Graph showing the relationship between the driving cycle and the amount of liquid ejected in a conventional driving signal.

[0020] Figure 13 This is a graph showing the relationship between the wave height value for each frequency in a conventional drive signal and the amount of liquid ejected.

[0021] Figure 14(a) to Figure 14(c) A diagram for explaining frequency characteristics.

[0022] Figure 15 This is a diagram for explaining the influence of frequency characteristics on the discharge amount.

[0023] Figure 16 This is a diagram for explaining the correction of the large dot driving signal in this embodiment.

[0024] Figure 17 Graph showing the relationship between the drive period and the amount of liquid ejected in the correction of the large dot drive signal according to this embodiment.

[0025] Figure 18 This is a diagram showing the discharge speed when the intermediate potential is changed during the connection of the driving period.

[0026] Figure 19 This is a graph showing the discharge speed when the potential change width during connection is changed.

[0027] Figure 20 This is a graph showing the landing deviation when the potential change width is changed at a conveying speed of 80 m / min.

[0028] Figure 21 This is a graph showing the landing deviation when the potential variation width is changed at a conveying speed of 40 m / min.

[0029] Figure 22 3 is a diagram showing a driving signal in the first modification example. DETAILED DESCRIPTION

[0030] Preferred embodiments of the present disclosure are described below with reference to the accompanying drawings. In the accompanying drawings, the dimensions and scales of various components may differ from actual dimensions, and some components may be schematically illustrated for ease of understanding. The scope of the present disclosure is not limited to these embodiments unless otherwise indicated in the following description.

[0031] The following description is appropriately made using mutually intersecting X-axis, Y-axis and Z-axis. In addition, hereinafter, a direction along the X-axis is the X1 direction, and the direction opposite to the X1 direction is the X2 direction. Similarly, directions opposite to each other along the Y-axis are the Y1 direction and the Y2 direction. Directions opposite to each other along the Z-axis are the Z1 direction and the Z2 direction. Typically, the Z-axis is a vertical axis, and the Z2 direction is equivalent to the downward direction in the vertical direction. However, the Z-axis may not be a vertical axis. In addition, although the X-axis, Y-axis and Z-axis are typically orthogonal to each other, they are not limited to this. For example, as long as they intersect at an angle within the range of 80° or more and 100° or less, it is sufficient. In addition, in this specification, "equal" means, in addition to being strictly equal, also including the meaning of manufacturing error and assembly error.

[0032] A: First embodiment

[0033] A1: Overall structure of the liquid ejection device 100

[0034] Figure 1 This is a schematic diagram illustrating an example structure of a liquid ejection device 100 according to the first embodiment. The liquid ejection device 100 is an inkjet printing device that ejects a liquid such as ink as droplets onto a medium M. The medium M is, for example, printing paper. Furthermore, the medium M is not limited to printing paper and may be any other material to be printed on, such as a resin film or fabric.

[0035] like Figure 1 As shown, the liquid ejection device 100 includes a liquid container 10 , a control unit 20 , a transport mechanism 30 , and a liquid ejection head 50 .

[0036] The liquid container 10 stores liquid. Specific examples of the liquid container 10 include a cartridge that is detachable from the liquid ejecting device 100, a bag-shaped liquid pack made of a flexible film, and a refillable liquid tank. The liquid stored in the liquid container 10 may be of any type.

[0037] The control unit 20 controls the operation of each element of the liquid ejection device 100. The control unit 20 includes, for example, one or more processing circuits such as a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array), and one or more storage circuits such as a semiconductor memory.

[0038] The conveying mechanism 30 conveys the medium M in the Y1 direction under the control of the control unit 20. The conveying mechanism 30 includes, for example, a long conveying roller extending along the X-axis and a motor that rotates the conveying roller. The conveying mechanism 30 is not limited to a structure using conveying rollers; for example, a roller or an endless belt may be used to convey the medium M while being attracted to the outer circumference by electrostatic force or the like.

[0039] A plurality of liquid ejection heads 50 are housed on a carriage 501. The plurality of liquid ejection heads 50 are arranged so as to extend over the entire range of the medium M along the X-axis. Under control by the control unit 20 based on image data Img, each liquid ejection head 50 ejects liquid supplied from the liquid container 10 onto the medium M from each of its plurality of nozzles. This ejection is performed in parallel with the transport of the medium M by the transport mechanism 30, thereby forming an image corresponding to the image data Img on the surface of the medium M, formed of liquid droplets.

[0040] A2: Electrical Structure of Liquid Dispensing Device 100

[0041] Figure 2 FIG. 1 is a diagram showing the electrical structure of the liquid ejection device 100 according to the first embodiment. Figure 2 As shown, each liquid ejecting head 50 includes a plurality of head chips 51 and a drive control unit 52 .

[0042] In the present embodiment, six head chips 51 are provided as the plurality of head chips 51. Specifically, two first head chips 51a, two second head chips 51b, and two third head chips 51c are provided.

[0043] Each head chip 51 has a plurality of ejection parts 510. Specifically, each first head chip 51a has a plurality of first ejection parts 510a. Each first ejection part 510a has a first drive element Ea. Each second head chip 51b has a plurality of second ejection parts 510b. Each second ejection part 510b has a second drive element Eb. Each third head chip 51c has a plurality of third ejection parts 510c. Each third ejection part 510c has a third drive element Ec. Furthermore, although this will be described later, each ejection part 510 has a nozzle N for ejecting liquid.

[0044] Under the control of the control unit 20, the drive control unit 52 switches whether to supply the drive signal Com output from the control unit 20 as the supply signal Vin to each of the plurality of ejection units 510 included in the head chip 51. Furthermore, the drive control unit 52 obtains ejection amount information InA related to the amount of droplets ejected from the nozzles N from each head chip 51 and transmits the information to the control unit 20.

[0045] The control unit 20 includes a control circuit 21 , a storage circuit 22 , a power supply circuit 23 , a drive signal generation circuit 24 , and a discharge amount information acquisition unit 25 .

[0046] The control circuit 21 has the function of controlling the operation of each part of the liquid ejection device 100 and the function of processing various data. The control circuit 21 includes, for example, a processor such as a CPU (Central Processing Unit). In addition, the control circuit 21 may also replace the CPU, or include a programmable logic device such as an FPGA (Field-Programmable Gate Array) in addition to the CPU. In addition, when the control circuit 21 is composed of multiple processors, the multiple processors may also be installed on different substrates, etc.

[0047] In addition, by executing the program, the control circuit 21 generates a control signal Sk1, a printing data signal SI, a waveform designation signal dCom, a latch signal LAT, a switching signal CNG, and a clock signal CLK as signals for controlling the operation of each part of the liquid ejection device 100.

[0048] The control signal Sk1 is a signal for controlling the drive of the transport mechanism 30. The print data signal SI is a digital signal for specifying the operating state of the drive element E. The latch signal LAT is a timing signal used in conjunction with the print data signal SI to specify the timing of liquid ejection from each nozzle N of the head chip 51.

[0049] The control circuit 21 includes a control unit 210 . The control unit 210 generates drive signal information InB that specifies the waveform of the drive signal Com based on the discharge amount information InA, and transmits the drive signal information InB to the drive signal generation circuit 24 .

[0050] The storage circuit 22 stores various programs executed by the control circuit 21 and various data such as image data Img processed by the control circuit 21. The storage circuit 22 includes, for example, a semiconductor memory including one or both of volatile memory such as RAM (Random Access Memory) and non-volatile memory such as ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), or PROM (Programmable Read-Only Memory). Image data Img is supplied from an external device 200 such as a personal computer or a digital camera. The storage circuit 22 is configured as part of the control circuit 21.

[0051] The power supply circuit 23 receives power from a commercial power source (not shown) and generates various predetermined potentials. The generated potentials are appropriately supplied to various components of the liquid ejection device 100. For example, the power supply circuit 23 generates a power supply potential VHV and a bias potential VBS. The bias potential VBS is supplied to the liquid ejection head 50. In addition, the power supply potential VHV is supplied to the drive signal generation circuit 24.

[0052] The drive signal generating circuit 24 is a circuit that repeatedly generates a drive signal Com for driving each drive element E included in each ejection portion 510. Specifically, the drive signal generating circuit 24 includes, for example, a DA conversion circuit and an amplifier circuit. In the drive signal generating circuit 24, the DA conversion circuit converts the waveform designation signal dCom from the control circuit 21 from a digital signal to an analog signal. The amplifier circuit amplifies the analog signal using the power supply potential VHV from the power supply circuit 23 to generate the drive signal Com. Among the waveforms included in the drive signal Com, the signal of the waveform actually supplied to the drive element E is the supply signal Vin described above. The waveform designation signal dCom is a digital signal for specifying the waveform of the drive signal Com.

[0053] The drive signal generating circuit 24 includes, for example, a first drive signal generating circuit 241 that generates a first drive signal ComAa, a second drive signal generating circuit 242 that generates a second drive signal ComC, and a third drive signal generating circuit 243 that generates a third drive signal ComAb. Furthermore, the drive signal generating circuit 24 also includes a drive signal generating circuit (not shown) that generates a fourth drive signal ComAc, a fifth drive signal ComBa, a sixth drive signal ComBb, and a seventh drive signal ComBc. The first drive signal ComAa, the second drive signal ComC, the third drive signal ComAb, the fourth drive signal ComAc, the fifth drive signal ComBa, the sixth drive signal ComBb, and the seventh drive signal ComBc will be described later.

[0054] A3: Configuration of Multiple Head Chips 51

[0055] Figure 3 for Figure 2 The bottom view of the liquid ejecting head 50 is shown. As described above, the liquid ejecting head 50 includes six mutually separated head chips 51. Each head chip 51 is strip-shaped and extends along the α-axis intersecting the X-axis and the Y-axis when viewed in the Z1 direction.

[0056] In this embodiment, the six head chips 51 are located at Figure 3 The two head chips 51 on the left side of the image are respectively designated as "first head chips 51a". Figure 3 The two head chips 51 in the center are respectively designated as "second head chips 51b". Figure 3 The two head chips 51 on the right side of FIG. 5 are respectively referred to as “third head chips 51 c ”.

[0057] The first head chip 51a has a plurality of first nozzles Na. The plurality of first nozzles Na are divided into two first nozzle columns La and arranged along the longitudinal direction of the first head chip 51a. Similarly, the second head chip 51b has a plurality of second nozzles Nb. The plurality of second nozzles Nb are divided into two second nozzle columns Lb and arranged along the longitudinal direction of the second head chip 51b. The third head chip 51c has a plurality of third nozzles Nc. The plurality of third nozzles Nc are divided into two third nozzle columns Lc and arranged along the longitudinal direction of the third head chip 51c. Each nozzle column L is a collection of a plurality of nozzles N that intersect with the X-axis and the Y-axis and are arranged in a straight line.

[0058] The planar shape of the plurality of nozzles N is, for example, circular, and they are formed to have the same opening area. The nozzles N belonging to each nozzle row L are arranged at equal intervals along the β axis orthogonal to the α axis.

[0059] A4: Partial Structure of Each Head Chip 51

[0060] Figure 4 To express Figure 3 FIG. 5 is a cross-sectional view of a portion of the head chip 51 shown in FIG. Figure 4 As shown, the head chip 51 includes a nozzle plate 11, a vibration absorber 12, a flow channel substrate 13, a pressure chamber substrate 14, a vibration plate 15, a wiring substrate 16, a frame 17, and a drive circuit 18. The nozzle plate 11, the vibration absorber 12, the flow channel substrate 13, the pressure chamber substrate 14, the vibration plate 15, the wiring substrate 16, and the frame 17 are each plate-shaped members that are long and narrow along the Y-axis. The nozzle plate 11, the flow channel substrate 13, the pressure chamber substrate 14, the vibration plate 15, and the wiring substrate 16 are arranged in this order in the Z1 direction.

[0061] The nozzle plate 11 is a plate-shaped member formed with a plurality of nozzles N. Each of the nozzles N is a circular through-hole through which liquid passes. The nozzles N eject liquid by the vibration of the vibration plate 15. The nozzle plate 11 is bonded to the flow path substrate 13 with, for example, an adhesive.

[0062] A flow channel for supplying liquid to the plurality of nozzles N is formed on the flow channel substrate 13. Specifically, a space Ra, a plurality of supply flow channels 131, a plurality of connecting flow channels 132, and a supply liquid chamber 133 are formed on the flow channel substrate 13. The space Ra is an elongated opening extending in the direction of the α-axis when viewed from above as viewed in the direction of the Z-axis. The supply flow channel 131 and the connecting flow channel 132 are through-holes formed for each nozzle N, respectively. The supply liquid chamber 133 is an elongated space extending in the direction of the α-axis across the plurality of nozzles N, and interconnects the space Ra and the plurality of supply flow channels 131. Each of the plurality of connecting flow channels 132 overlaps with a nozzle N corresponding to the connecting flow channel 132 when viewed from above. The pressure chamber substrate 14 is bonded to the flow channel substrate 13, for example, by an adhesive.

[0063] The pressure chamber substrate 14 is provided with multiple pressure chambers C. Each pressure chamber C is formed for each nozzle N and is an elongated space extending along the β-axis when viewed from above. The multiple pressure chambers C are arranged in a row along the α-axis. The pressure chambers C are located between the flow path substrate 13 and the vibration plate 15. The pressure chambers C communicate with the nozzles N via the communication channel 132 and with the space Ra via the supply channel 131 and the supply liquid chamber 133.

[0064] The nozzle plate 11, the flow path substrate 13, and the pressure chamber substrate 14 are each manufactured by processing a single crystal silicon substrate using, for example, dry etching or wet etching. However, other known methods may be used as appropriate for manufacturing the nozzle plate 11, the flow path substrate 13, and the pressure chamber substrate 14.

[0065] A vibration plate 15 is disposed on the surface facing the Z1 direction of the pressure chamber substrate 14. The vibration plate 15 is a plate-shaped member that can vibrate elastically.

[0066] A plurality of drive elements E corresponding to the nozzles N are arranged on the surface of the vibration plate 15 facing the Z1 direction. Each drive element E is in the shape of a long strip extending in the direction along the β-axis when viewed from above. The plurality of drive elements E are arranged in the direction along the α-axis corresponding to the plurality of pressure chambers C. The drive element E is driven in a manner that changes the volume of the pressure chamber C according to the supply signal Vin generated from the drive signal Com. In other words, the drive element E is deformed by the application of voltage. When the vibration plate 15 vibrates in conjunction with the deformation, the pressure in the pressure chamber C changes, causing the liquid to be ejected from the nozzle N.

[0067] The frame portion 17 is a housing for storing the liquid supplied to the plurality of pressure chambers C. Figure 4 As shown, a space Rb is formed in the frame portion 17. Space Rb in the frame portion 17 communicates with space Ra in the flow path substrate 13. The space formed by space Ra and space Rb functions as a liquid reservoir, or liquid storage chamber R, for storing liquid supplied to the multiple pressure chambers C. Liquid is supplied to the liquid storage chamber R via an inlet 171 formed in the frame portion 17. The liquid in the liquid storage chamber R is supplied to the pressure chambers C via the supply liquid chamber 133 and each supply flow channel 131.

[0068] The vibration absorbing body 12 is a flexible film constituting the wall surface of the liquid storage chamber R. The vibration absorbing body 12 is a plastic substrate that absorbs pressure fluctuations of the liquid in the liquid storage chamber R.

[0069] The wiring substrate 16 is a plate-shaped component on which wiring is formed for electrically connecting the drive circuit 18 and a plurality of drive elements E. The wiring substrate 16 is, for example, a rigid substrate. On the wiring substrate 16, wiring is formed for electrically connecting the drive circuit 18 mounted on the surface facing the Z1 direction and a plurality of bumps 16B required for driving each drive element E, which are mounted on the surface facing the Z2 direction. The drive circuit 18 constitutes a part of the drive control unit 52 described above, and has an IC (Integrated Circuit) chip that outputs a supply signal Vin and a bias potential VBS obtained based on the drive signal Com for driving each drive element E. In addition, a flexible wiring substrate (not shown) connected to the control unit 20 is connected to the wiring substrate 16.

[0070] In addition, the wiring substrate 16 can be a flexible substrate such as FFC (Flexible Flat Cable), or an FPC (Flexible Printed Circuit) or COF (Chip ON Film) with a driving circuit 18 mounted on the substrate.

[0071] In the head chip 51, each ejection unit 510 described above includes a nozzle N, a pressure chamber C, and a driving element E. In this embodiment, the nozzle N, the pressure chamber C, the supply flow channel 131 and the communication flow channel 132, and the portion of the vibration plate 15 corresponding to the driving element E constitute a single ejection unit 510.

[0072] Furthermore, the pressure chamber C and the drive element E of the first ejection portion 510a of the first nozzle row La are referred to as the "first pressure chamber Ca" and the "first drive element Ea." The pressure chamber C and the drive element E of the second ejection portion 510b of the second nozzle row Lb are referred to as the "second pressure chamber Cb" and the "second drive element Eb." The pressure chamber C and the drive element E of the third ejection portion 510c of the third nozzle row Lc are referred to as the "third pressure chamber Cc" and the "third drive element Ec."

[0073] In addition, the structure of each head chip 51 is not limited to Figure 4 Each head chip 51 may have, for example, a circulation channel for circulating liquid.

[0074] A5: driving signal Com

[0075] Figure 5 is a diagram for explaining the driving signal Com, wherein the driving signal Com is used to generate Figure 3The first nozzle array La shown in FIG. 1 supplies a supply signal Vin. Figure 6 is a diagram for explaining the driving signal Com, wherein the driving signal Com is used to generate Figure 3 The second nozzle array Lb shown supplies a supply signal Vin. Figure 7 is a diagram for explaining the driving signal Com, wherein the driving signal Com is used to generate Figure 3 The third nozzle column Lc shown supplies a supply signal Vin.

[0076] Figures 5 to 7 The latch signal LAT shown includes a pulse PlsL for defining a drive cycle Tu. The drive cycle Tu corresponds to a printing cycle for forming dots formed by droplets from the nozzle N on the medium M. The drive cycle Tu is defined, for example, as the period from the rising edge of the pulse PlsL to the rising edge of the next pulse PlsL. The specific length or period of the drive cycle Tu is not particularly limited.

[0077] As mentioned above, in Figure 2 The driving signal generating circuit 24 generates driving signals Com, which include, for example, a first driving signal ComAa, a third driving signal ComAb, a fourth driving signal ComAc, a fifth driving signal ComBa, a sixth driving signal ComBb, a seventh driving signal ComBc, and a second driving signal ComC.

[0078] like Figure 5 As shown, during one driving period Tu, any of the first driving signal ComAa, the fifth driving signal ComBa, and the second driving signal ComC is supplied from the driving control unit 52 as a supply signal Vin to one electrode of each first driving element Ea belonging to the first nozzle array La. In addition, a bias potential VBS is supplied to the other electrode of each first driving element Ea. Although not shown in detail, Figure 2The drive control unit 52 includes a switching circuit 701. Although not shown in detail, the switching circuit 701 is connected to a signal line that transmits the first drive signal ComAa, a signal line that transmits the fifth drive signal ComBa, a signal line that transmits the second drive signal ComC, a signal line that transmits the print data signal SI1 corresponding to the first nozzle array La, a signal line that transmits the clock signal CLK, and a signal line that transmits the latch signal LAT. Based on the clock signal SCK, the print data signal SI1, and the latch signal LAT, the switching circuit 701 selects any one of the first drive signal ComAa, the fifth drive signal ComBa, and the second drive signal ComC to generate a supply signal Vin corresponding to each first drive element Ea, and outputs the supply signal Vin to a wiring line connected to one electrode of each of the plurality of first drive elements Ea.

[0079] like Figure 6 As shown, during one driving period Tu, any of the third driving signal ComAb, the sixth driving signal ComBb, and the second driving signal ComC is supplied from the driving control unit 52 as a supply signal Vin to one electrode of each second driving element Eb belonging to the second nozzle array Lb. In addition, a bias potential VBS is supplied to the other electrode of each second driving element Eb. Although not shown in detail, Figure 2 The drive control unit 52 includes a switching circuit 702. Although not shown in detail, the switching circuit 702 is connected to a signal line that transmits the third drive signal ComAb, a signal line that transmits the sixth drive signal ComBb, a signal line that transmits the second drive signal ComC, a signal line that transmits the print data signal SI2 corresponding to the second nozzle column Lb, a signal line that transmits the clock signal CLK, and a signal line that transmits the latch signal LAT. Based on the clock signal SCK, the print data signal SI2, and the latch signal LAT, the switching circuit 702 selects any of the third drive signal ComAb, the sixth drive signal ComBb, and the second drive signal ComC to generate a supply signal Vin corresponding to each second drive element Eb, and outputs the supply signal Vin to a wiring line connected to one electrode of each of the plurality of second drive elements Eb.

[0080] like Figure 7 As shown, during one driving period Tu, any of the fourth driving signal ComAc, the seventh driving signal ComBc, and the second driving signal ComC is supplied from the driving control unit 52 as the supply signal Vin to one electrode of each third driving element Ec belonging to the third nozzle column Lc. In addition, a bias potential VBS is supplied to the other electrode of each third driving element Ec. Although not shown in detail, Figure 2The drive control unit 52 includes a switching circuit 703. Although not shown in detail, the switching circuit 703 is connected to a signal line that transmits the fourth drive signal ComAc, a signal line that transmits the seventh drive signal ComBc, a signal line that transmits the second drive signal ComC, a signal line that transmits the print data signal SI3 corresponding to the third nozzle column Lc, a signal line that transmits the clock signal CLK, and a signal line that transmits the latch signal LAT. Based on the clock signal SCK, the print data signal SI3, and the latch signal LAT, the switching circuit 703 selects any of the fourth drive signal ComAc, the seventh drive signal ComBc, and the second drive signal ComC to generate a supply signal Vin corresponding to each third drive element Ec, and outputs the supply signal Vin to a wiring line connected to one electrode of each of the plurality of third drive elements Ec.

[0081] Figure 5 The first driving signal ComAa, Figure 6 The third driving signal ComAb and Figure 7 The fourth drive signal ComAc is a signal for forming a large dot, which is the "first amount of droplets." Due to manufacturing and assembly variations among the multiple head chips 51, even if the same drive signal Com is used to eject the same droplets, there will be slight variations in the amount ejected from the nozzles N for each head chip 51. To reduce this variation, the drive signal Com supplied to each head chip 51, particularly the signal for forming a large dot, is adjusted.

[0082] For example, the first drive signal ComAa is generated based on the average discharge volume of the two first head chips 51a. Similarly, the third drive signal ComAb is generated based on the average discharge volume of the two second head chips 51b. The fourth drive signal ComAc is generated based on the average discharge volume of the two third head chips 51c. Furthermore, the first drive signal ComAa, the third drive signal ComAb, and the fourth drive signal ComAc are generated to reduce the difference in discharge volume between the first head chip 51a, the second head chip 51b, and the third head chip 51c.

[0083] Furthermore, the fifth drive signal ComBa, the sixth drive signal ComBb, and the seventh drive signal ComBc are signals for ejecting smaller dots than larger dots. Similarly, the fifth drive signal ComBa is generated based on the average ejection volume of the two first head chips 51a. Similarly, the sixth drive signal ComBb is generated based on the average ejection volume of the two second head chips 51b. The seventh drive signal ComBc is generated based on the average ejection volume of the two third head chips 51c. Furthermore, the fifth drive signal ComBa, the sixth drive signal ComBb, and the seventh drive signal ComBc are generated to reduce the difference in ejection volume between the first head chip 51a, the second head chip 51b, and the third head chip 51c.

[0084] Furthermore, the second drive signal ComC is a signal for driving the drive element E in such a manner as to prevent the liquid in the nozzle N from thickening, thereby causing the meniscus MN of the nozzle N to vibrate slightly to such an extent that the liquid is not ejected from the nozzle N. The second drive signal ComC is not a signal for ejecting liquid, and therefore does not cause a difference in the ejection amount. Therefore, the second drive signal ComC is a common signal for all head chips 51.

[0085] like Figure 5 As shown, the first drive signal ComAa includes a first start potential holding element a1, a first pulse PAa, and a first end potential holding element a7. Figure 2 The first drive signal generating circuit 241 shown generates a first drive signal ComAa having a first pulse PAa to be supplied to the first drive element Ea when a large dot is ejected from the first nozzle Na.

[0086] like Figure 5 As shown, the first starting potential holding element a1 is an element that maintains the first potential E1a from the start of a drive cycle Tu to the start of the first pulse PAa. In this embodiment, the first potential E1a is the midpoint of the first pulse PAa and is different from the reference potential E0. The reference potential E0 is, for example, a higher potential than the bias potential VBS.

[0087] The first end potential holding element a7 is an element that maintains the first potential E1a from the end of the first pulse PAa to the end of one drive cycle Tu. While the first end potential holding element a7 maintains the first potential E1a in this embodiment, it may also maintain a potential other than the first potential E1a, such as the reference potential E0. Therefore, while the first start potential holding element a1 and the first end potential holding element a7 have the same potential in this embodiment, they may also be different.

[0088] The first pulse PAa has, in sequence, an expansion element a2, a maintenance element a3, an ejection element a4, a maintenance element a5, and a recovery element a6. The expansion element a2 is an element that drives the first drive element Ea by changing the potential to expand the volume of the first pressure chamber Ca. The expansion element a2 changes the potential from the first potential E1a to the minimum potential Ex of the first pulse PAa. The maintenance element a3 is an element that maintains the minimum potential Ex. The ejection element a4 is an element that drives the first drive element EA to eject a large dot as a "first amount of droplet" from the first nozzle Na by changing the potential after the expansion element a2 to shrink the volume of the expanded first pressure chamber Ca. The ejection element a4 changes the potential from the minimum potential Ex to the maximum potential E2a of the first pulse PAa. The maintenance element a5 is an element that maintains the maximum potential E2a. The recovery element a6 is an element that returns from the maximum potential E2a to the first potential E1a.

[0089] like Figure 6 As shown, the third drive signal ComAb includes a third start potential holding element b1, a third pulse PAb, and a third end potential holding element b7. Figure 2 The third drive signal generating circuit 243 shown generates a third drive signal ComAb having a third pulse PAb to be supplied to the second drive element Eb when a large dot is ejected from the second nozzle Nb.

[0090] The third starting potential holding element b1 maintains the third potential E1b from the start of a drive cycle Tu to the start of the third pulse PAb. The third potential E1b is the intermediate potential of the third pulse PAb and, in this embodiment, is equal to the reference potential E0. Furthermore, the third potential E1b is different from the first potential E1a described above.

[0091] The third end potential maintaining element b7 is an element that maintains the third potential E1b from the end of the third pulse PAb to the end of one drive cycle Tu. Furthermore, in this embodiment, the third end potential maintaining element b7 may also maintain a potential other than the third potential E1b. Therefore, while the third start potential maintaining element b1 and the third end potential maintaining element b7 have the same potential in this embodiment, they may also be different.

[0092] The third pulse PAb sequentially comprises an expansion element b2, a sustaining element b3, an ejection element b4, a sustaining element b5, and a recovery element b6. The expansion element b2 drives the second drive element Eb by changing the potential, thereby expanding the volume of the second pressure chamber Cb. The expansion element b2 changes the potential from the third potential E1b to the minimum potential Ex of the third pulse PAb. The sustaining element b3 maintains the minimum potential Ex. While this minimum potential Ex is the same as the minimum potential Ex of the first pulse PAa described above, it may be different. The ejection element b4 drives the second drive element Eb by changing the potential after the expansion element b2, thereby contracting the volume of the expanded second pressure chamber Cb, thereby ejecting a large dot, the "first amount of droplet," from the second nozzle Nb. The ejection element b4 changes the potential from the minimum potential Ex to the maximum potential Ey of the third pulse PAb. The sustaining element b5 maintains the maximum potential Ey. This maximum potential Ey is lower than the maximum potential E2a of the first pulse PAa described above. The recovery element b6 is an element for recovering from the maximum potential Ey to the third potential E1b.

[0093] like Figure 7 As shown, the fourth drive signal ComAc includes a fourth start potential holding element c1 , a fourth pulse PAc, and a fourth end potential holding element c7 . Figure 2 The driving signal generating circuit 24 shown generates a fourth driving signal ComAc having a fourth pulse PAc to be supplied to the third driving element Ec when a large dot is ejected from the third nozzle Nc.

[0094] The fourth starting potential holding element c1 maintains the fourth potential E1c from the start of a drive cycle Tu to the start of the fourth pulse PAc. The fourth potential E1c is an intermediate potential of the fourth pulse PAc. In this embodiment, the fourth potential E1c is different from the first potential E1a and the reference potential E0 described above.

[0095] The fourth end potential maintaining element c7 is an element that maintains the fourth potential E1c from the end of the fourth pulse PAc to the end of one drive cycle Tu. Furthermore, in this embodiment, the fourth end potential maintaining element c7 may also maintain a potential other than the fourth potential E1c, such as the reference potential E0. Therefore, while the fourth start potential maintaining element c1 and the fourth end potential maintaining element c7 are the same potential in this embodiment, they may also be different.

[0096] The fourth pulse PAc sequentially comprises an expansion element c2, a maintenance element c3, an ejection element c4, a maintenance element c5, and a recovery element c6. The expansion element c2 is an element that drives the third drive element Ec by changing the potential to expand the volume of the third pressure chamber Cc. The expansion element c2 changes the potential from the fourth potential E1c to the minimum potential Ex of the fourth pulse PAc. The maintenance element c3 is an element that maintains the minimum potential Ex. Although this minimum potential Ex is the same as the minimum potential Ex of the first pulse PAa described above, it may also be different. The ejection element c4 is an element that drives the third drive element Ec to eject a large dot as a "first amount of droplet" from the third nozzle Nc by changing the potential after the expansion element c2 to shrink the volume of the expanded third pressure chamber Cc. The ejection element c4 changes the potential from the minimum potential Ex to the maximum potential E2c of the fourth pulse PAc. The maintenance element c5 is an element that maintains the maximum potential E2c. The maximum potential E2c is lower than the maximum potential E2a of the first pulse PAa and the maximum potential Ey of the third pulse PAb described above. The recovery element c6 is an element for recovering from the maximum potential E2c to the fourth potential E1c.

[0097] Figure 5 The fifth driving signal ComBa shown includes a fifth start potential holding element d1 , a fifth pulse PBa, and a fifth end potential holding element d2 . Figure 2 The driving signal generating circuit 24 shown generates a fifth driving signal ComBa having a fifth pulse PBa to be supplied to the first driving element Ea when a small dot is ejected from the first nozzle Na.

[0098] The fifth starting potential holding element d1 is an element that maintains the first potential E1a from the start of a drive cycle Tu to the start of the fifth pulse PBa. The fifth ending potential holding element d2 is an element that maintains the first potential E1a from the end of the fifth pulse PBa to the end of the drive cycle Tu. While the potentials of the fifth starting potential holding element d1 and the fifth ending potential holding element d2 are the same, they may be different. Furthermore, the potentials of the fifth starting potential holding element d1 and the fifth ending potential holding element d2 may be other than the first potential E1a.

[0099] The fifth pulse PBa drops from the first potential E1a to a potential lower than the first potential E1a, maintains this potential, then rises to a potential higher than the first potential E1a, maintains this potential, then changes to a potential lower than the first potential E1a, and maintains this potential. Then, the fifth pulse PBa maintains this lower potential, then rises to a potential higher than the first potential E1a, and maintains this potential, then returns to the first potential E1a.

[0100] Figures 5 to 7 The second drive signal ComC shown includes a second start potential holding element e1 , a second pulse PC, and a second end potential holding element e5 . Figure 2 The second drive signal generating circuit 242 generates a second drive signal ComC having a second pulse PC that is different from the first pulse PAa described above. The second pulse PC is a micro-vibration pulse supplied to the first drive element Ea to vibrate the liquid in the first nozzle Na so that it is prevented from being ejected. Furthermore, the second pulse PC is a micro-vibration pulse supplied to the second drive element Eb to vibrate the liquid in the second nozzle Nb so that it is prevented from being ejected. Furthermore, the second pulse PC is a micro-vibration pulse supplied to the third drive element Ec to vibrate the liquid in the third nozzle Nc so that it is prevented from being ejected.

[0101] The second starting potential maintaining element e1 is an element that maintains the second potential E3 from the start of a drive cycle Tu to the start of the second pulse PC. The second ending potential maintaining element e5 is an element that maintains the second potential E3 from the end of the second pulse PC to the end of a drive cycle Tu. In this embodiment, the second potential E3 is equal to the reference potential E0. Furthermore, while the potentials of the second starting potential maintaining element e1 and the second ending potential maintaining element e5 are the same, they may be different. Furthermore, the potentials of the second starting potential maintaining element e1 and the second ending potential maintaining element e5 may be other than the reference potential E0.

[0102] This second pulse PC is a trapezoidal wave and sequentially comprises an expansion element e2, a sustaining element e3, and a contraction element e4. The expansion element e2 causes the potential to change from the second potential E3 to the minimum potential Ez of the second pulse PC. The sustaining element e3 maintains the minimum potential Ez. The contraction element e4 returns the potential from the minimum potential Ez to the second potential E3.

[0103] Figure 6 The sixth driving signal ComBb shown includes a sixth start potential holding element f1 , a sixth pulse PBb, and a sixth end potential holding element f2 . Figure 2The drive signal generation circuit 24 shown generates a sixth drive signal ComBb comprising a sixth pulse PBb, which is supplied to the second drive element Eb when ejecting a small dot from the second nozzle Nb. A sixth start potential holding element f1 and a sixth end potential holding element f2 maintain the third potential E1b. While the sixth pulse PBb is similar to the fifth pulse PBa, the potentials and potential change rates are set to eject a small dot from the second nozzle Nb.

[0104] Figure 7 The seventh driving signal ComBc shown includes a seventh start potential holding element g1 , a seventh pulse PBc, and a seventh end potential holding element g2 . Figure 2 The drive signal generation circuit 24 shown generates a seventh drive signal ComBc having a seventh pulse PBc, which is supplied to the third drive element Ec when ejecting a small dot from the third nozzle Nc. A seventh starting potential holding element g1 and a seventh ending potential holding element g2 maintain the fourth potential E1c. While the seventh pulse PBc is similar to the fifth pulse PBa, the potentials and potential change rates are set to eject a small dot from the third nozzle Nc.

[0105] Figure 8 : is a diagram showing an example of a case where the driving cycle Tu is continuous. Figure 8 For example, in the first driving cycle Tu, each of the plurality of ejecting units 510 performs ejection driving to form a large dot as a "first amount of liquid droplets." In the second driving cycle Tu, each of the plurality of ejecting units 510 performs micro-vibration driving. In the third driving cycle Tu, each of the plurality of ejecting units 510 performs ejection driving to form a large dot. In the fourth driving cycle Tu, each of the plurality of ejecting units 510 performs ejection driving to form a large dot.

[0106] Figure 8 (a) shows a driving waveform of a supply signal Vin supplied to the first driving element Ea of the first head chip 51 a. Figure 8 (b) shows the driving waveform of the supply signal Vin supplied to the second driving element Eb of the second head chip 51b. Figure 8 (c) shows the driving waveform of the supply signal Vin supplied to the third driving element Ec of the third head chip 51c.

[0107] like Figure 8As shown in FIG. 1 , in the first head chip 51a, the first drive signal ComAa is supplied to each first drive element Ea during the third drive cycle Tu and the fourth drive cycle Tu. The first end potential holding element a7 of the first drive signal ComAa in the third drive cycle Tu and the first start potential holding element a1 of the first drive signal ComAa in the fourth drive cycle Tu are both the first potential E1a, and the first potential E1a continues in the portion connecting the two drive cycles Tu.

[0108] Furthermore, in the first head chip 51a, the first drive signal ComAa is supplied to each first drive element Ea during the first drive cycle Tu, and the second drive signal ComC is supplied to each first drive element Ea during the second drive cycle Tu. The first end potential holding element a7 of the first drive signal ComAa during the first drive cycle Tu and the second start potential holding element e1 of the second drive signal ComC during the second drive cycle Tu have different potentials.

[0109] like Figure 8 As shown in FIG. 2( b ), in the second head chip 51 b, the third drive signal ComAb is supplied to each second drive element Eb during the third drive cycle Tu and the fourth drive cycle Tu. The third end potential holding element b7 of the third drive signal ComAb in the third drive cycle Tu and the third start potential holding element b1 of the third drive signal ComAb in the fourth drive cycle Tu are both the third potential E1b, and the third potential E1b is continuous in the portion connecting the two drive cycles Tu.

[0110] Furthermore, in the second head chip 51b, the third drive signal ComAb is supplied to each second drive element Eb during the first drive cycle Tu, and the second drive signal ComC is supplied to each second drive element Eb during the second drive cycle Tu. The third end potential holding element b7 of the third drive signal ComAb in the first drive cycle Tu and the second start potential holding element e1 of the second drive signal ComC in the second drive cycle Tu have the same potential, and the reference potential E0 continues in the connecting portion of the two drive cycles Tu.

[0111] like Figure 8As shown in FIG. 3 (c), in the third head chip 51c, the fourth drive signal ComAc is supplied to each third drive element Ec during the third drive cycle Tu and the fourth drive cycle Tu. The fourth end potential holding element c7 of the fourth drive signal ComAc in the third drive cycle Tu and the fourth start potential holding element c1 of the fourth drive signal ComAc in the fourth drive cycle Tu are both the fourth potential E1c, and the fourth potential E1c is continuous in the portion connecting the two drive cycles Tu.

[0112] Furthermore, in the third head chip 51c, the fourth drive signal ComAc is supplied to each third drive element Ec during the first drive cycle Tu, and the second drive signal ComC is supplied to each third drive element Ec during the second drive cycle Tu. The fourth end potential holding element c7 of the fourth drive signal ComAc in the first drive cycle Tu has a different potential from the second start potential holding element e1 of the second drive signal ComC in the second drive cycle Tu.

[0113] Figure 9 as well as Figure 10 are diagrams for explaining the supply of the drive signal Com. Figure 9 As shown, the same drive signal Com, which is a drive signal related to liquid ejection, is supplied to the head chips 51 arranged in the Y1 direction, which is the conveyance direction of the medium M. Specifically, the first drive signal ComAa and the fifth drive signal ComBa, described above, are supplied to the two first head chips 51a. The third drive signal ComAb and the sixth drive signal ComBb, described above, are supplied to the two second head chips 51b. The fourth drive signal ComAc and the seventh drive signal ComBc, described above, are supplied to the two third head chips 51c.

[0114] In addition, in this embodiment, if Figure 10 As shown, the second drive signal ComC not related to the ejection of the liquid from the nozzle N is a common signal in the head chips 51 arranged in the X1 direction intersecting the conveying direction of the medium M. Specifically, for the head chips 51 located at Figure 10 The same second drive signal ComC is supplied to the first head chip 51a, the second head chip 51b and the third head chip 51c in the upper section. Figure 10 The drive signal generating circuit 24 can also generate a first head chip 51a, a second head chip 51b and a third head chip 51c in the lower section and supply the same second drive signal ComC. Figure 10The second drive signal ComC having the second pulse PC is supplied to the drive element E of the first head chip 51a, the second head chip 51b and the third head chip 51c in the upper section, and the second drive signal ComC having the second pulse PC is supplied to the drive element E of the first head chip 51a, the second head chip 51b and the third head chip 51c in the upper section. Figure 10 The drive signal generating circuit 24 may generate one second drive signal ComC and supply the same second drive signal ComC to all of the first to third head chips 51a, 51b, and 51c.

[0115] In addition, although the second driving signal ComC is the same in all the head chips 51 in this embodiment, it may also be the same in all the head chips 51. Figure 10 The upper and lower sections of the circuit are supplied with second drive signals ComC having waveform shapes different from each other.

[0116] In this way, the signal supply path can be changed using a signal related to liquid ejection and a signal unrelated to liquid ejection. In addition, both the signal related to liquid ejection and the signal unrelated to liquid ejection can be supplied to each head chip 51 arranged in the Y1 direction, which is the conveyance direction of the medium M.

[0117] Figure 11 FIG. 1 is a diagram for explaining the correction of the conventional drive signal ComAx. Figure 11 As shown in FIG. 1 , conventionally, in order to make the ejection amount of the liquid consistent with the desired ejection amount, the peak value Vh is corrected without changing the intermediate potential of the drive signal ComAx. Specifically, for example, Figure 11 (a) is used as a reference for the drive signal ComAx. When the ejection amount is insufficient, the wave height value Vh is increased, thereby Figure 11 The driving signal ComAx shown in (a) is corrected to Figure 11 (b) shows the drive signal ComAx. However, in this case, even if the peak value Vh is increased, the liquid discharge amount may not match the desired amount. Specifically, it is more difficult to match the liquid discharge amount to the desired amount in high-frequency driving than in low-frequency driving.

[0118] Figure 12 Graph showing the relationship between the drive cycle Tu and the ejection amount Iw of the liquid in the conventional drive signal ComAx. Figure 12, the diagram shows the cases where the ratio of the intermediate potential to the peak value Vh is 40% and 50%. Without changing the intermediate potential, the peak value Vh is larger in the case where the ratio is 40% than in the case where the ratio is 50%.

[0119] like Figure 12 As shown, by changing the ratio of the intermediate potential to the peak value Vh from 50% to 40%, that is, increasing the peak value Vh, the liquid discharge volume Iw increases at 40 μs or longer. However, the change in discharge volume is smaller with a shorter drive period Tu, that is, at a higher frequency, than with a longer drive period Tu, that is, at a lower frequency. In other words, the change in discharge volume per 1V of the peak value Vh decreases with higher frequency drive.

[0120] Figure 13 Graph showing the relationship between the wave height value Vh for each frequency in the conventional drive signal ComAx and the discharge amount Iw of the liquid. Figure 13 In FIG, the relationship between the wave height value Vh and the ejection amount Iw at 5.0kHz, 31.5kHz and 63.0kHz is shown. Figure 13 As shown, at 63.0 kHz, even when the peak value Vh is varied, the change in discharge volume Iw is smaller than at 5.0 kHz and 31.5 kHz. In other words, the change in discharge volume per 1V of the peak value Vh is smaller at high-frequency drive than at low-frequency drive. Therefore, if the correction value for the peak value Vh is increased to ensure sufficient discharge volume during high-frequency drive, the droplet discharge velocity may become excessively faster than desired during low-frequency drive. This may result in landing deviation.

[0121] Figure 14(a) to Figure 14(c)14(a) is a diagram illustrating frequency characteristics. The frequency characteristics shown in FIG14(a) are determined by the sum of the relationship between the drive frequency and the discharge volume Iw, which is influenced by the Tm vibration, which is the vibration of the meniscus MN of the nozzle N shown in FIG14(b), and the relationship between the drive frequency and the discharge volume Iw, which is influenced by the Tc vibration, which is the vibration within the flow channel of the discharge unit 510 shown in FIG14(c). In particular, the influence of the Tm vibration is greater in high-frequency drive. Therefore, in low-frequency drive, the influence of the residual vibration of the Tc vibration after the discharge of the droplets and the influence of the refill of the Tm vibration after the discharge of the liquid are smaller than in high-frequency drive. In low-frequency drive, the next drive signal Com is applied after the meniscus MN returns to its non-driven state. On the other hand, in high-frequency drive, the discharge volume is easily affected by the Tm vibration of the meniscus MN of the nozzle N and the Tc vibration within the flow channel of the discharge unit 510, and thus the discharge volume is easily changed.

[0122] Figure 15 This is a diagram for explaining the effect of frequency characteristics on the ejection volume. Figure 15 In FIG, the ratio of the intermediate potential to the peak value Vh is 50% and 40%, and the change of the ejection amount Iw corresponding to the driving frequency is shown, and the difference in the change of the ejection amount Iw in the high frequency region is shown. Figure 15 The vertical axis shows the variation rate [%] of the discharge amount when the discharge amount Iw in the low-frequency region where the ratio is 50% and 40% is set to 100%. Figure 15 As shown, when the ratio of the intermediate potential to the peak value Vh is 40%, the rate of change in the discharge volume decreases compared to when it is 50%. In other words, during high-frequency operation, even if the correction amount for the peak value Vh is increased without changing the intermediate potential, the discharge volume Iw is unlikely to increase. Therefore, with conventional correction methods that only change the peak value Vh, increasing the discharge volume Iw becomes increasingly difficult as the frequency of the operation increases.

[0123] Figure 16 1 is a diagram for explaining the correction of the large dot drive signal ComA in this embodiment. Figure 16 As shown, in this embodiment, the intermediate potential is corrected simultaneously with the correction of the peak value Vh.

[0124] Specifically, for example, Figure 16 When the driving signal ComA for the large dot shown in (a) is supplied to the driving element E of the head chip 51 and the amount of droplets ejected from the nozzle N is insufficient for the large dot, the peak value Vh is increased and the intermediate potential is raised to correct the amount. Figure 16 The large dot shown in (b) uses the driving signal ComA. Figure 16(a) The driving signal ComA of the large point is the same as that described above. Figure 6 The third drive signal ComAb shown is the same. Figure 16 (b) The driving signal ComA of the large point is the same as that described above. Figure 5 The first drive signal ComAa shown is the same.

[0125] In addition, for example, Figure 16 When the driving signal ComA for the large dot shown in (a) is supplied to the driving element E of the head chip 51 and the amount of droplets ejected from the nozzle N is excessive relative to the large dot, the peak value Vh is reduced and the intermediate potential is lowered to correct the situation to Figure 16 The large dot shown in (c) uses the driving signal ComA. Figure 16 (c) The large point driving signal ComA is the same as the above-mentioned Figure 7 The fourth drive signal ComAc shown is the same.

[0126] In this manner, in this embodiment, the intermediate potential is corrected simultaneously with the correction of the peak value Vh. Therefore, compared with the case of correcting only the peak value Vh, the discharge amount can be increased while suppressing the peak value Vh even in high-frequency driving.

[0127] Figure 17 : is a diagram showing the relationship between the drive cycle Tu and the liquid discharge amount Iw in the correction of the large dot drive signal ComA in this embodiment. Figure 17 , the diagram shows the relationship between the drive cycle Tu and the ejection volume Iw when the first drive signal ComAa and the third drive signal ComAb are supplied to the drive element E of a predetermined head chip 51. The potential change amplitude D2a, which is the peak value Vh of the first drive signal ComAa, is larger than the potential change amplitude D2b, which is the peak value Vh of the third drive signal ComAb. Furthermore, the first potential E1a, which is the first starting potential holding element a1, which is the intermediate potential of the first drive signal ComAa, is larger than the third potential E1b (reference potential E0), which is the third starting potential holding element b1, which is the intermediate potential of the third drive signal ComAb. Therefore, the ratio of the intermediate potential to the peak value Vh of the first drive signal ComAa and the third drive signal ComAb is the same, both 50%.

[0128] like Figure 17As shown, the first drive signal ComAa has a larger discharge volume than the third drive signal ComAb, regardless of the frequency. In this embodiment, the discharge volume of the first drive signal ComAa increases in the same manner as in the low-frequency region, even in the high-frequency region, compared to the third drive signal ComAb. That is, in the drive signal ComA having the waveform shape of the third drive signal ComAb, the discharge volume can be increased by supplying the drive signal ComA having the waveform shape of the first drive signal ComAa to the head chip 51 that discharges a smaller discharge volume than the discharge volume equivalent to a larger dot. Therefore, in this embodiment, the decrease in the change in discharge volume per 1V due to frequency is reduced compared to the past.

[0129] In addition, the fourth drive signal ComAc can also be said to be the same as the above content.

[0130] Furthermore, as previously described, the first potential E1a of the first starting potential holding element a1 of the first drive signal ComAa is different from the second potential E3 of the second starting potential holding element e1 of the second drive signal ComC. Thus, by making the potentials of the first starting potential holding element a1 of the first drive signal ComAa and the second starting potential holding element e1 of the second drive signal ComC different, the degree of design freedom can be increased compared to a case where the potentials are the same. For example, as previously described, by adjusting the first potential E1a in addition to the wave height value Vh, it is easy to make the ejection amount and ejection speed close to the desired amount and speed. As previously described, since the intermediate potential is corrected at the same time as the wave height value Vh is corrected, it is less likely to be affected by the changes in the frequency characteristics described above, making it easy to adjust the ejection amount and ejection speed to the desired amount and speed.

[0131] Furthermore, as previously mentioned, the reference potential E0, which serves as the "third potential" of the third start potential holding element b1 of the third drive signal ComAb, differs from the first potential E1a of the first start potential holding element a1 of the first drive signal ComAa. This ensures flexibility in the design of the first and third drive signals ComAa. Consequently, when ejecting the same large dot using the first nozzle Na and the second nozzle Nb, the different potentials of the first start potential holding element a1 and the third start potential holding element b1 allow for more accurate alignment of ejection volumes compared to the same situation. In other words, this difference in ejection volume can be minimized.

[0132] In addition, if Figure 5 or Figure 6As shown, the potential change amplitude D1a of the expansion element a2 of the first pulse PAa differs from the potential change amplitude D1b of the expansion element b2 of the third pulse PAb. Furthermore, the potential change amplitude D2a of the ejection element a4 of the first pulse PAa differs from the potential change amplitude D2b of the ejection element b4 of the third pulse PAb. Thus, due to the difference in potential between the first starting potential holding element a1 and the third starting potential holding element b1, the potential change amplitudes D1a and D1b differ, and the potential change amplitudes D2a and D2b differ. Therefore, as described above, the influence of frequency characteristics can be reduced, thereby reducing the difference in ejection volume between the first nozzle Na and the second nozzle Nb, which are the same large droplet.

[0133] In addition, the first drive signal ComAa is supplied to the first drive element Ea, but not to the second drive element Eb. The third drive signal ComAb is supplied to the second drive element Eb, but not to the first drive element Ea. In addition, the second drive signal ComC including the second pulse PC as a micro-vibration pulse is supplied to the first drive element EA and the second drive element Eb. That is, the first drive signal ComAa is a dedicated ejection drive signal for ejecting a large dot from the first nozzle NA, and the third drive signal ComAb is a dedicated ejection drive signal for ejecting a large dot from the second nozzle Nb. On the other hand, the second drive signal ComC is not a signal related to ejection, but a micro-vibration drive signal that only vibrates the curved liquid surface MN. By using this micro-vibration drive signal in common in multiple drive elements E, it is possible to suppress the complication of the drive signal generating circuit 24.

[0134] The second potential E3 of the second starting potential holding element e1 is within the range from the first potential E1a of the first starting potential holding element a1 to the third potential E1b of the third starting potential holding element b1. In this embodiment, the second potential E3 is the same as the third potential E1b.

[0135] Since the second potential E3 is within the range, compared with the case outside the range, even if Figure 8 Even when the first pulse PAa and the second pulse PC are continuous, as in the first and second drive cycles Tu in (a), the potential difference at the junction of the drive cycle Tu for supplying the first pulse PAa and the drive cycle Tu for supplying the second pulse PC can be suppressed from becoming excessively large. This allows for stable ejection and micro-vibration driving. This prevents unintended droplet ejection during micro-vibration driving, or unstable ejection volume and velocity during large-drop ejection.

[0136] Furthermore, the first end potential holding element a7 of the first drive signal ComAa maintains the first potential E1a which is the same as the first start potential holding element a1. Figure 8 When the first pulse PAa is continuously ejected in the third and fourth drive cycles Tu as shown in (a), a potential difference can be avoided from occurring at the connection between the two drive cycles Tu, thereby enabling stable ejection.

[0137] Similarly, the third end potential holding element b7 of the third drive signal ComAb maintains the third potential E1b which is the same as the third start potential holding element b1. Figure 8 When the third pulse PAb is continuously ejected as shown in the third and fourth drive cycles Tu in (b), a potential difference can be avoided from occurring at the connection between the two drive cycles Tu. Therefore, stable ejection can be achieved.

[0138] The maximum ejection frequency achieved by the first drive signal ComAa and the third drive signal ComAb is preferably 10 kHz or higher. In the high frequency region of 10 kHz or higher, the first potential E1a and the third potential E1b are different, so that the above effect can be significantly exerted.

[0139] Furthermore, considering the discharge stability, the maximum discharge frequency achieved by the first drive signal ComAa and the third drive signal ComAb is, for example, approximately 150 kHz or less.

[0140] In addition, as mentioned above Figure 2 As shown, the control unit 20 includes a discharge volume information acquisition unit 25 and a control unit 210. The discharge volume information acquisition unit 25 acquires first discharge volume information InAa related to the volume of droplets discharged from the first nozzle Na. Furthermore, the control unit 210 generates first drive signal information InBa that specifies the waveform of the first drive signal ComAa based on the first discharge volume information InAa, and transmits the first drive signal information InBa to the first drive signal generation circuit 241. Based on the first discharge volume information InAa, the control unit 210 changes at least one of the potential change width D1a of the expansion element a2 of the first pulse PAa, the potential change width D2a of the discharge element a4 of the first pulse PAa, and the first potential E1a.

[0141] For example, during use of the liquid ejection head 50, the ejection volume may vary due to temporal changes in the shape of the components constituting the liquid ejection head 50, the temperature at the location of use, and the like. Even in such cases, by providing the control unit 20 with the ejection volume information acquisition unit 25 and the control unit 210, the ejection volume can be adjusted to a desired level in accordance with the temporal changes and the temperature at the location of use. Furthermore, the difference in ejection volume between multiple nozzles N ejecting the same droplet size can be reduced.

[0142] Furthermore, the discharge amount information acquisition unit 25 acquires second discharge amount information InAb related to the amount of droplets discharged from the second nozzle Nb. Furthermore, the control unit 210 generates second drive signal information InBb that specifies the waveform of the third drive signal ComAb based on the second discharge amount information InAb, and transmits the second drive signal information InBb to the second drive signal generation circuit 242. Based on the second discharge amount information InAb, the control unit 210 changes at least one of the potential change width D1b of the expansion element b2 of the third pulse PAb, the potential change width D2b of the discharge element b4 of the third pulse PAb, and the third potential E1b.

[0143] By providing the aforementioned discharge volume information acquisition unit 25 and control unit 210, it is possible to minimize differences in discharge volume between the first nozzle Na and the second nozzle Nb when the same large dot is discharged from both nozzles Na and Nb due to the aforementioned temporal changes and the temperature of the location of use. Furthermore, the discharge volume information acquisition unit 25 and control unit 210 correct the potential change amplitude and intermediate potential for other pulses in the same manner as described above. This reduces differences in discharge volume between multiple nozzles N that discharge the same droplet size.

[0144] Figure 18 Graph showing the ejection velocity Vm of a droplet when a large dot is ejected in the latter drive cycle Tu when the intermediate potential is changed when two drive cycles Tu are connected. Figure 18 LL1 shows the state of the droplet ejection velocity Vm when a large dot is ejected in the rear drive cycle Tu, when the intermediate potential does not change when two drive cycles Tu are connected. Figure 18 LL2 represents the state of the droplet ejection speed Vm when a large dot is ejected in the rear driving cycle Tu when the middle potential of the rear driving cycle Tu is +2V different from the middle potential of the front driving cycle Tu when the two driving cycles Tu are connected. Figure 18LL3 represents the state of the droplet ejection velocity Vm when a large dot is ejected in the rear driving cycle Tu when the middle potential of the rear driving cycle Tu is -2V different from the middle potential of the front driving cycle Tu when two driving cycles Tu are connected. Figure 18 In the example shown, when the driving cycle changes, the period from the start of the driving cycle to the start of the ejection pulse changes.

[0145] like Figure 18 As shown, when the intermediate potential is changed during the connection of the drive cycle Tu, the potential change drives the driving element E, generating pressure oscillations in the liquid within the pressure chamber C and the nozzle N. If the ejection pulse is applied at a resonant or non-resonant timing during this pressure oscillation, the ejection characteristics will change significantly. Therefore, it is preferable to use the length of the first starting potential holding element a1 within a range where the potential difference between the intermediate potentials during the connection of the drive cycle Tu has a minimal effect on the ejection speed.

[0146] Specifically, preferably, Figure 5 The period tx from the start of the first starting potential holding element a1 to the middle position of the expansion element a2 of the first pulse PAa satisfies the following mathematical formula.

[0147] 0.25×TC+n≤tx≤0.75×TC+n

[0148] Here, the above-mentioned TC is the natural vibration period of the first ejection part 510a, and n is a natural number.

[0149] By making the period tx satisfy the above-mentioned formula, compared with a case where the above-mentioned formula is not satisfied, even if the intermediate potential is changed when the driving cycle Tu is connected, the stability of the discharge can be improved.

[0150] Furthermore, it is preferable that the period tx satisfies the following mathematical formula.

[0151] tx=0.5×TC+n

[0152] By making the period tx satisfy the above-mentioned formula, the discharge stability can be improved more significantly compared to the case where the period tx does not satisfy the above-mentioned formula.

[0153] Likewise, preferably, from Figure 6 The period tx from the start of the third starting potential holding element b1 to the middle position of the expansion element b2 of the third pulse PAb satisfies the following mathematical expression.

[0154] 0.25×TC+n≤tx≤0.75×TC+n

[0155] Here, the above-mentioned TC is the natural vibration period of the second ejection part 510b, and n is a natural number.

[0156] By making the period tx satisfy the above-mentioned formula, compared with a case where the above-mentioned formula is not satisfied, even if the intermediate potential is changed when the driving cycle Tu is connected, the stability of the discharge can be improved.

[0157] Furthermore, it is preferable that the period tx satisfies the following mathematical formula.

[0158] tx=0.5×TC+n

[0159] By making the period tx satisfy the above-mentioned formula, the discharge stability can be improved more significantly compared to the case where the period tx does not satisfy the above-mentioned formula.

[0160] Figure 19 The figure shows the ejection speed Vm when the potential change width Vx is changed when the drive cycles Tu are connected. In other words, the potential change width Vx represents the difference between the middle potential of the front drive cycle Tu and the middle potential of the rear drive cycle Tu in two consecutive drive cycles Tu. Figure 19 As shown in FIG. 1 , the greater the absolute value of the potential variation width Vx during the connection of the drive cycle Tu, the greater the influence on the ejection speed Vm.

[0161] The potential variation width Vx during connection is preferably 4.0 V or less. Therefore, the difference between the first potential E1a and the second potential E3 is preferably 4.0 V or less. By setting this difference to 4.0 V or less, the discharge stability can be improved compared to when it exceeds 4.0 V.

[0162] Likewise, the difference between the second potential E3 and the third potential E1b is preferably not more than 4.0 V. By setting the difference to not more than 4.0 V, the stability of discharge can be improved compared to a case where the difference exceeds 4.0 V.

[0163] Figure 20 This is a graph showing the landing deviation when the potential variation width Vx is changed at a conveying speed of 80 m / min. Figure 21 This is a graph showing the spraying deviation when the potential variation width Vx is changed at a conveying speed of 40 m / min. Figure 20 as well as Figure 21 As shown, a larger potential variation amplitude Vx results in more unstable discharge, leading to greater dropout variation. Furthermore, a higher transport speed increases the impact of the potential variation amplitude Vx. Taking this dropout variation into account, the potential variation amplitude Vx is preferably 4.0V or less.

[0164] As described above, in the driving method of the liquid ejection device 100, the first potential E1A of the first starting potential holding element a1 of the first drive signal ComAa is set to be different from the second potential E3 of the second starting potential holding element e1 of the second drive signal ComC. Thus, by setting the first starting potential holding element a1 of the first drive signal ComAa and the second starting potential holding element e1 of the second drive signal ComC to have different potentials, the degree of design freedom can be increased compared to a case where these potentials are the same. Therefore, as described above, by adjusting the first potential E1a in addition to the wave height value Vh, for example, it is easier to bring the ejection amount and ejection speed closer to the desired amount and speed. Therefore, according to the driving method of the liquid ejection device 100 of this embodiment, it is possible to achieve sufficient correction of the ejection amount and ejection speed.

[0165] B: Modification

[0166] The various methods illustrated above can be modified in various ways. In the following, specific modified methods that can be applied to the various methods described above are illustrated. Two or more methods arbitrarily selected from the following examples can be appropriately combined within the scope of non-contradiction.

[0167] B1. First Modification

[0168] Figure 22 FIG. 1 is a diagram showing the first drive signal ComAa of the first modified example. Although the potential change from the reference potential E0 to the first potential E1a is relatively steep in the embodiment described above, Figure 22 As in the first modification example, the change can also be relatively gentle. Thus, it is possible to suppress the situation where the ejection becomes unstable due to the change in the potential change amplitude Vx during the connection described above. In addition, the same method is used for other drive signals Com other than the first drive signal ComAa.

[0169] B2. Other Modifications

[0170] In the above-described embodiment, each head chip 51 includes two nozzle rows L. However, the number of nozzle rows included in each head chip 51 may be one, or three or more.

[0171] The "first amount of liquid droplets" is not limited to large dots, but may be medium or small dots. In addition, the "first amount of liquid droplets" refers to the size of the liquid droplets, without considering the difference in discharge amount caused by manufacturing errors and assembly errors of the nozzle N.

[0172] While the intermediate potential of the fifth drive signal ComBa is set to the first potential E1a, which is the intermediate potential of the first drive signal ComAa, in the embodiment described above, this is not limiting. The intermediate potential of the fifth drive signal ComBa can also be set to a different potential from the first potential E1a, which is the intermediate potential of the first drive signal ComAa. This further increases the degree of freedom in designing the ejection pulse. In this case, the difference between the intermediate potential of the fifth drive signal ComBa and the first potential E1a, which is the intermediate potential of the first drive signal ComAa, is preferably set to be the same as the potential variation amplitude Vx described above. Furthermore, the duration of the fifth starting potential holding element d1 is preferably set in the same manner as the duration tx from the start of the first starting potential holding element a1 to the midpoint of the expansion element a2 of the first pulse PAa. In such a configuration, the fifth drive signal ComBa can also be equivalent to the "second drive signal." In this case, the fifth pulse PBa of the fifth drive signal ComBa is equivalent to the "second pulse," and the starting potential of one drive cycle of the fifth drive signal ComBa is equivalent to the "second potential." Similarly, the intermediate potential of the sixth drive signal ComBb can also be set to a potential different from the third potential E1b which is the intermediate potential of the third drive signal ComAb, and the intermediate potential of the seventh drive signal ComBc can also be set to a potential different from the fourth potential E1c which is the intermediate potential of the fourth drive signal ComAc.

[0173] In the above-described embodiment, the second head chip 51b may be considered the "first head chip," and the first head chip 51a or the third head chip 51c may be considered the "second head chip." In this case, the second nozzle Nb, the second pressure chamber Cb, the second drive element Eb, and the second discharge portion 510b may be considered the "first nozzle," the "first pressure chamber," the "first drive element," and the "first discharge portion." The first nozzle Na, the first pressure chamber Ca, the first drive element Ea, and the first discharge portion 510a, or the third nozzle Nc, the third pressure chamber Cc, the third drive element Ec, and the third discharge portion 510c may be considered the "second nozzle," the "second pressure chamber," the "second drive element," and the "second discharge portion." Similarly, the third head chip 51c may be considered the "first head chip," and the first head chip 51a or the second head chip 51b may be considered the "second head chip." In this case, the third nozzle Nc, the third pressure chamber Cc, the third drive element Ec, and the third discharge portion 510c may be considered the "first nozzle," the "first pressure chamber," the "first drive element," and the "first discharge portion." The first nozzle Na, the first pressure chamber Ca, the first drive element Ea and the first ejection part 510a, or the second nozzle Nb, the second pressure chamber Cb, the second drive element Eb and the second ejection part 510b are equivalent to the "second nozzle", "second pressure chamber", "second drive element" and "second ejection part".

[0174] Although the embodiment described above is a line-type liquid ejecting device 100 in which multiple nozzles N are distributed across the entire width of the medium M, the present disclosure can also be applied to a serial-type liquid ejecting device in which a carriage 501 carrying a liquid ejecting head 50 moves back and forth.

[0175] The liquid ejecting device 100 exemplified in the above-described manner can be used in various devices such as fax machines or copiers in addition to being used for dedicated printing, and the use of the present disclosure is not particularly limited. Of course, the use of the liquid ejecting device is not limited to printing. For example, a liquid ejecting device that ejects a solution of a color material can be used as a manufacturing device for forming a color filter for a display device such as a liquid crystal display panel. In addition, a liquid ejecting device that ejects a solution of a conductive material can be used as a manufacturing device for forming wiring or electrodes of a wiring substrate. In addition, a liquid ejecting device that ejects a solution of an organic matter related to a living organism can be used as a manufacturing device for manufacturing, for example, a biochip.

[0176] Although the present invention has been described above based on preferred embodiments, the present invention is not limited to the aforementioned embodiments. In addition, the configuration of each part of the present invention can be replaced with any configuration that exhibits the same functions as the aforementioned embodiments, and any configuration can be added.

[0177] Explanation of symbols

[0178] 24…driving signal generating circuit; 25…discharge amount information acquiring unit; 50…liquid ejecting head; 51a…first head chip; 51b…second head chip; 51c…third head chip; 52…driving control unit; 100…liquid ejecting device; 210…control unit; 241…first driving signal generating circuit; 242…second driving signal generating circuit; 243…third driving signal generating circuit; 510a…first ejecting unit; 510b…second ejecting unit; 510c…third ejecting unit Ca…first pressure chamber; Cb…second pressure chamber; Cc…third pressure chamber; ComAa…first drive signal; ComAb…third drive signal; ComC…second drive signal; D1a…potential change amplitude; D1b…potential change amplitude; D2A…potential change amplitude; D2b…potential change amplitude; E1a…first potential; E1b…third potential; E3…second potential; Ea…first drive element; Eb…second drive element; Ec…third drive element; InAa…first ejection volume information; InAb…second ejection volume information; InBa…first drive signal information; InBb…second drive signal information; La…first nozzle array; Lb…second nozzle array; Lc…third nozzle array; Na…first nozzle; Nb…second nozzle; Nc…third nozzle; PAa…first pulse; PAb…third pulse; PC…second pulse; Tu…drive period; Vx…potential change amplitude; a1…first starting potential holding element; a2…expansion element; a3…maintenance element; a4…ejection element; a5…maintenance element; a6…recovery element; a7…first ending potential holding element; b1…third starting potential holding element; b2…expansion element; b3…maintenance element; b4…ejection element; b6…recovery element; b7…third ending potential holding element; e1…second starting potential holding element; e2…expansion element; e3…maintenance element; e4…contraction element; e5…second ending potential holding element; tx…period.

Claims

1. A liquid ejection device, characterized in that: have: A liquid ejection head including a first ejection portion, the first ejection portion including a first nozzle for ejecting liquid, a first pressure chamber communicating with the first nozzle, and a first driving element driven so as to change a volume of the first pressure chamber in response to a driving signal; a first drive signal generating circuit for generating a first drive signal having a first pulse to be supplied to the first drive element when a first amount of droplets is ejected from the first nozzle; a second drive signal generating circuit that generates a second drive signal supplied to the first drive element and having a second pulse different from the first pulse; The first drive signal includes a first starting potential maintaining element for maintaining a first potential from the start of one drive cycle to the start of the first pulse. The second drive signal has a second starting potential maintaining element for maintaining the second potential from the start of one drive cycle to the start of the second pulse. The first potential is different from the second potential.

2. The liquid ejection device according to claim 1, wherein The first pulse includes an expansion element and an ejection element, wherein the expansion element drives the first driving element to expand the volume of the first pressure chamber by changing the potential, and the ejection element drives the first driving element to eject a first amount of droplets from the first nozzle by contracting the volume of the expanded first pressure chamber by changing the potential after the expansion element. The period tx from the start of the first starting potential holding element to the middle position of the expansion element of the first pulse satisfies the following mathematical formula: 0.25×TC+n≤tx≤0.75×TC+n Here, TC is the natural vibration period of the first ejection part, and n is a natural number.

3. The liquid ejecting device according to claim 1, wherein The period tx from the start of the first starting potential holding element to the middle position of the expansion element of the first pulse satisfies the following mathematical formula: tx=0.5×TC+n Here, TC is the natural vibration period of the first ejection part, and n is a natural number.

4. The liquid ejecting device according to claim 1, wherein The first drive signal includes a first end potential maintaining element for maintaining the first potential from the end of the first pulse to the end of one drive cycle.

5. The liquid ejecting device according to claim 1, wherein The difference between the first potential and the second potential is 4.0 V or less.

6. The liquid ejecting device according to claim 1, wherein The maximum ejection frequency achieved by the first drive signal and the second drive signal is 10 kHz or higher.

7. The liquid ejecting device according to claim 1, wherein Also features: a discharge amount information acquisition unit that acquires first discharge amount information related to the amount of liquid droplets discharged from the first nozzle; a control unit configured to generate first drive signal information that specifies the waveform of the first drive signal based on the first discharge amount information, and transmit the first drive signal information to the first drive signal generation circuit; The first pulse includes an expansion element and an ejection element, wherein the expansion element drives the first driving element to expand the volume of the first pressure chamber by changing the potential, and the ejection element drives the first driving element to eject a first amount of droplets from the first nozzle by contracting the volume of the expanded first pressure chamber by changing the potential after the expansion element. The control unit generates the first drive signal information that specifies the waveform of the first drive signal based on the first ejection volume information, wherein the first drive signal is a drive signal that changes at least one of the potential change amplitude of the expansion element of the first pulse, the potential change amplitude of the ejection element of the first pulse, and the first potential.

8. The liquid ejecting device according to claim 1, wherein The liquid ejection head further includes a second ejection portion including a second nozzle for ejecting liquid, a second pressure chamber connected to the second nozzle, and a second driving element driven in a manner to change the volume of the second pressure chamber according to a driving signal. The liquid ejection device further includes a third drive signal generating circuit that generates a third drive signal having a third pulse to be supplied to the second drive element when ejecting a first amount of liquid droplets from the second nozzle. The third driving signal includes a third starting potential maintaining element for maintaining a third potential from the start of one driving cycle to the start of the third pulse. The third potential is different from at least the first potential.

9. The liquid ejecting device according to claim 8, wherein: The second pulse is a micro-vibration pulse supplied to the first driving element when the first driving element is driven to vibrate so as not to eject the liquid in the first nozzle, and supplied to the second driving element when the second driving element is driven to vibrate so as not to eject the liquid in the second nozzle. The first drive signal is supplied to the first drive element but not to the second drive element, The third driving signal is supplied to the second driving element but not to the first driving element. The second drive signal is supplied to the first drive element and the second drive element.

10. The liquid ejecting device according to claim 8, wherein The first pulse includes an expansion element and an ejection element, wherein the expansion element drives the first driving element to expand the volume of the first pressure chamber by changing the potential, and the ejection element is an element that contracts the volume of the expanded first pressure chamber by changing the potential after the expansion element, thereby ejecting a first amount of droplets from the first nozzle. The third pulse includes an expansion element and an ejection element, wherein the expansion element drives the second driving element to expand the volume of the second pressure chamber by changing the potential, and the ejection element is an element that contracts the expanded volume of the second pressure chamber by changing the potential after the expansion element, thereby ejecting a first amount of droplets from the second nozzle. The potential change amplitude of the expansion element of the first pulse is different from the potential change amplitude of the expansion element of the third pulse. The potential change width of the ejection element of the first pulse is different from the potential change width of the ejection element of the third pulse.

11. The liquid ejecting device according to claim 8, wherein The period tx from the start of the first start potential holding element to the middle position of the ejection element of the first pulse, and the period tx from the start of the third start potential holding element to the middle position of the ejection element of the third pulse satisfy the following mathematical formula: 0.25×TC+n≤tx≤0.75×TC+n Here, TC is the natural vibration period of the second ejection part, and n is a natural number.

12. The liquid ejecting device according to claim 8, wherein The period tx from the start of the first start potential holding element to the middle position of the ejection element of the first pulse, and the period tx from the start of the third start potential holding element to the middle position of the ejection element of the third pulse satisfy the following mathematical formula: tx=0.5×TC+n Here, TC is the natural vibration period of the second ejection part, and n is a natural number.

13. The liquid ejecting device according to claim 8, wherein The first drive signal includes a first end potential maintaining element for maintaining the first potential from the end of the first pulse to the end of one drive cycle. The third drive signal includes a third end potential maintaining element for maintaining the third potential from the end of the third pulse to the end of one drive cycle.

14. The liquid ejecting device according to claim 8, wherein The difference between the first potential and the second potential is 4.0 V or less, The difference between the second potential and the third potential is 4.0 V or less.

15. The liquid ejecting device according to claim 8, wherein The second potential is a potential within a range from the first potential to the third potential.

16. The liquid ejecting device according to claim 8, wherein Also features: a discharge amount information acquisition unit that acquires first discharge amount information related to the amount of liquid droplets discharged from the first nozzle and second discharge amount information related to the amount of liquid droplets discharged from the second nozzle; a control unit configured to generate first drive signal information specifying a waveform of the first drive signal based on the first discharge amount information, and to generate second drive signal information specifying a waveform of the second drive signal based on the second discharge amount information, and to transmit the first drive signal information to the first drive signal generating circuit and the second drive signal information to the third drive signal generating circuit; The first pulse includes an expansion element and an ejection element, wherein the expansion element drives the first driving element in such a manner that the volume of the first pressure chamber expands by changing the potential, and the ejection element is an element that contracts the volume of the expanded first pressure chamber by changing the potential after the expansion element, thereby ejecting droplets from the first nozzle. The third pulse includes an expansion element and an ejection element, wherein the expansion element drives the second driving element by changing the potential to expand the volume of the second pressure chamber, and the ejection element is an element that contracts the expanded volume of the second pressure chamber by changing the potential after the expansion element to eject droplets from the second nozzle. The control unit changes the potential change width of the expansion element of the first pulse, the potential change width of the ejection element of the first pulse, and the first potential based on the first ejection amount information. The control unit changes the potential change width of the expansion element of the third pulse, the potential change width of the ejection element of the third pulse, and the third potential based on the second ejection amount information.

17. A method for driving a liquid ejecting device, characterized in that: The liquid ejection device includes a liquid ejection head, wherein the liquid ejection head includes a first ejection portion, the first ejection portion including a first nozzle for ejecting liquid, a first pressure chamber connected to the first nozzle, and a first driving element driven in a manner to change the volume of the first pressure chamber according to a driving signal. In the driving method of the liquid ejecting device, When a first amount of droplets is ejected from the first nozzle, a first drive signal having a first pulse is generated and supplied to the first drive element, and generating a second drive signal supplied to the first drive element and having a second pulse different from the first pulse, When the first drive signal and the second drive signal are generated, the first potential of the first starting potential holding element of the first drive signal from the beginning of one drive cycle to the beginning of the first pulse is set to be different from the second potential of the second starting potential holding element of the second drive signal from the beginning of one drive cycle to the beginning of the second pulse.

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