Liquid ejecting head

Abstract

The invention provides a liquid ejection head capable of suppressing the influence of crosstalk from a surrounding driving channel and performing stable liquid ejection. According to one embodiment, a liquid ejection head includes a retardation setting unit and a plurality of drive channels. Each of the plurality of drive channels is provided with a nozzle and an actuator, and the actuator corresponds to the nozzle. The retardation amount setting unit sets the retardation amount of the drive waveform applied to the actuator for each of the plurality of drive channels in which the nozzles are arranged in a row. In the direction in which the nozzles are arranged, the relative retardation of each of the drive channels with respect to a front adjacent drive channel alternately takes a value greater than a target retardation and a value smaller than the target retardation, and then either the value greater than the target retardation or the value smaller than the target retardation is brought closer to the target retardation. And inverting the phase of the change in the amount of retardation.

Description

Technical Field

[0001] Embodiments of the present invention relate to a liquid ejection head. Background Art

[0002] There is known a liquid ejection head that supplies a predetermined amount of liquid to a predetermined position. The liquid ejection head is mounted on, for example, an inkjet printer, a 3D printer, a dispensing device, etc. The inkjet printer ejects droplets of ink from an inkjet head to form an image or the like on the surface of a recording medium. The 3D printer ejects droplets of a modeling material from a modeling material ejection head and cures them to form a three-dimensional object. The dispensing device ejects droplets of a sample to supply a predetermined amount to a plurality of containers or the like.

[0003] The liquid ejection head has a plurality of channels for ejecting liquid. Each channel includes a nozzle for ejecting liquid, a pressure chamber communicating with the nozzle, and an actuator for changing the volume of the pressure chamber. The liquid ejection head selects a channel for ejecting liquid from the plurality of channels and gives a drive signal to the actuator to drive the actuator. When the actuator is driven, the volume of the pressure chamber filled with liquid changes, and liquid is ejected from the nozzle.

[0004] In a multi-nozzle liquid ejection head that ejects liquid from a plurality of nozzles, the ejection of liquid may be unstable due to mechanical factors, fluid factors, electrical factors, etc. and be affected by the liquid ejection operations of surrounding channels. This is called crosstalk. In particular, mechanical crosstalk is strongly affected by channels arranged close to each other. For example, when the nozzles are arranged in a row, it is strongly affected by two adjacent channels. To avoid mechanical crosstalk, it is desirable that the timing of driving the actuator maintains a predetermined relationship with the two adjacent channels on each side. On the other hand, to avoid electrical crosstalk, it is desirable to disperse the timing of driving the actuator as much as possible. For such reasons, it is difficult to balance avoiding mechanical crosstalk and avoiding electrical crosstalk.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: International Publication WO2017 / 145743

[0008] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2021-138032

[0009] Patent Document 3: Japanese Unexamined Patent Application Publication No. 2003-320670 Summary of the Invention

[0010] Technical Problem to be Solved by the Invention

[0011] The technical problem to be solved by the present invention is to provide a liquid ejection head that can suppress the influence of crosstalk received from surrounding drive channels and can eject liquid stably.

[0012] Solution for solving the technical problem

[0013] The liquid ejection head according to an embodiment of the present invention includes a plurality of drive channels and a delay amount setting unit. Each of the plurality of drive channels includes a nozzle and an actuator corresponding to the nozzle. The delay amount setting unit sets the delay amount of the drive waveform applied to the actuator for each of the plurality of drive channels arranged in a line with the nozzles. In the arrangement direction of the nozzles, the relative delay amount of each drive channel with respect to the adjacent drive channel in front alternately takes a value larger than the target delay amount and a value smaller than the target delay amount, and then makes either the value larger than the target delay amount or the value smaller than the target delay amount approach the target delay amount, and reverses the phase of the change in the delay amount. Description of the drawings

[0014] Figure 1 It is an overall structure diagram of an inkjet printer equipped with an inkjet head according with the embodiment.

[0015] Figure 2 It is a perspective view of the above inkjet head.

[0016] Figure 3 It is an internal structure diagram of the above inkjet head.

[0017] Figure 4 It is a cross-sectional view of the actuator of the above inkjet head.

[0018] Figure 5 It is the drive waveform applied to the above actuator.

[0019] Figure 6 It is an operation explanatory diagram of the actuator to which the above drive waveform is applied.

[0020] Figure 7 It is the set values of a plurality of delay amounts with the timing of applying the above drive waveform shifted.

[0021] Figure 8 It is an explanatory diagram showing the shift of timing caused by a plurality of delay amounts using a waveform diagram.

[0022] Figure 9 It is an explanatory diagram of a drive circuit that assigns a plurality of delay amounts to each drive waveform.

[0023] Figure 10 It is an explanatory diagram showing the result of assigning a plurality of delay amounts to each drive channel.

[0024] Figure 11 A graph showing the relationship of the delay amounts between the respective drive channels.

[0025] Figure 12 A graph showing the absolute value of the relative delay between each drive channel and the adjacent drive channel in front and the front-back average of the absolute value of the relative delay.

[0026] Figure 13 A graph showing the front delay difference, the rear delay difference, and their average of the drive channels respectively assigned the delay amounts of the first group and the second group.

[0027] Figure 14 A graph showing the relationship of the sub-delay amounts between the respective drive channels.

[0028] Figure 15 An explanatory diagram showing a comparative example of the allocation of a plurality of delay amounts.

[0029] Figure 16 A graph showing the absolute value of the relative delay between each drive channel of the above comparative example and the adjacent drive channel in front and the front-back average of the absolute value of the relative delay.

[0030] Figure 17 A graph showing the relationship of the delay amounts between the respective drive channels of the above comparative example.

[0031] Figure 18 Other examples of the drive waveforms applied to the above actuator.

[0032] Figure 19 Other examples of the drive waveforms applied to the above actuator. Detailed Description of the Preferred Embodiment

[0033] The liquid ejection head according to the embodiment will be described in detail below with reference to the accompanying drawings. It should be noted that in the respective drawings, the same reference numerals are assigned to the same structures.

[0034] As an example of an image forming apparatus equipped with the liquid ejection head of the embodiment, an inkjet printer 10 that prints an image on a recording medium will be described. Figure 1 The schematic structure of the inkjet printer 10 is shown. Inside the housing 11 of the inkjet printer 10, there are arranged: a cassette 12 that houses a sheet S as an example of a recording medium, an upstream conveyance path 13 for the sheet S, a conveyor belt 14 that conveys the sheet S taken out from inside the cassette 12, a plurality of inkjet heads 100 to 103 that eject ink droplets toward the sheet S on the conveyor belt 14, a downstream conveyance path 15 for the sheet S, a discharge tray 16, and a control board 17. An operation unit 18 serving as a user interface is arranged on the upper side of the housing 11.

[0035] The image data printed on the sheet S is generated, for example, by a computer 200 as an external connection device. The image data generated by the computer 200 is sent to the control board 17 of the inkjet printer 10 via a cable 201, connectors 202, 203.

[0036] The pickup roller 204 supplies the sheets S one by one from the cassette 12 to the upstream conveyance path 13. The upstream conveyance path 13 is constituted by feed roller pairs 131, 132 and sheet guide plates 133, 134. The sheet S is conveyed to the upper surface of the conveyor belt 14 via the upstream conveyance path 13. The arrow 104 in the figure shows the conveyance path of the sheet S from the cassette 12 to the conveyor belt 14.

[0037] The conveyor belt 14 is a net-shaped endless belt formed with a plurality of through holes on the surface. The conveyor belt 14 is rotatably supported by three rollers, a driving roller 141, driven rollers 142, 143. The motor 205 rotates the conveyor belt 14 by rotationally driving the driving roller 141. The motor 205 is an example of a driving device. The arrow 105 in the figure shows the rotation direction of the conveyor belt 14. A negative pressure container 206 is disposed on the back side of the conveyor belt 14. The negative pressure container 206 is connected to a fan 207 for decompression. The fan 207 makes the inside of the negative pressure container 206 negative pressure by the formed air flow, so as to adsorb and hold the sheet S on the upper surface of the conveyor belt 14. The arrow 106 in the figure shows the flow of the air flow.

[0038] The inkjet heads 100 to 103, which are an example of a liquid ejection head, are arranged to face the sheet S adsorbed and held on the conveyor belt 14 with a minute gap of, for example, 1 mm therebetween. The inkjet heads 100 to 103 eject droplets of ink toward the sheet S respectively. The inkjet heads 100 to 103 print an image when the sheet S passes thereunder. The inkjet heads 100 to 103 have the same structure except for the color of the ejected ink. The colors of the ink are, for example, cyan, magenta, yellow, and black.

[0039] The inkjet heads 100 to 103 are respectively connected to ink tanks 315 to 318 and ink supply pressure adjusting devices 321 to 324. The ink tanks 315 to 318 are arranged above the inkjet heads 100 to 103 respectively. During standby, the ink supply pressure adjusting devices 321 to 324 adjust the inside of the inkjet heads 100 to 103 to a negative pressure, for example, -1.2 kPa relative to the atmospheric pressure, so that ink does not leak from the nozzles 20 (refer to Figure 2 ) of the inkjet heads 100 to 103. At the time of image formation, the ink supply pressure adjusting devices 321 to 324 supply the ink in the ink tanks 315 to 318 to the inkjet heads 100 to 103 respectively.

[0040] After image formation, the sheet S is conveyed from the conveyor belt 14 to the downstream conveyance path 15. The downstream conveyance path 15 is constituted by feed roller pairs 151, 152, 153, 154 and sheet guide plates 155, 156 that define the conveyance path of the sheet S. The sheet S is conveyed from the discharge port 157 to the discharge tray 16 via the downstream conveyance path 15. Arrow 107 in the figure indicates the conveyance path of the sheet S.

[0041] Next, the structure of the inkjet heads 100 to 103 will be described. The following will refer to Figures 2 to 4 The inkjet head 100 will be described, but the inkjet heads 101 to 103 have the same structure as the inkjet head 100.

[0042] As Figures 2 to 4 shown, the inkjet head 100 includes a head 2 as an example of a liquid ejection unit. The head 2 is connected to a flexible printed wiring board 3 as an example of a thin film wiring board. The flexible printed wiring board 3 is connected to a print circuit board 4 as an example of a relay board.

[0043] The multi-nozzle head 2 includes: a nozzle plate 21 on which a plurality of nozzles 20 are arranged, an actuator substrate 22 on which actuators corresponding to the respective nozzles 20 are formed, a frame member 23 that forms a common ink chamber 26, and an ink supply unit 24 that supplies ink to the common ink chamber 26.

[0044] The nozzle plate 21 is, for example, a rectangular plate formed of a resin such as polyimide or a metal such as stainless steel. The nozzles 20 that eject ink are arranged in a row in the X direction of the first direction on the surface of the nozzle plate 21. It should be noted that arranging in a row does not necessarily mean that the centers of the nozzles 20 are on a straight line, and for example, they may be offset in the Y direction of the second direction. The nozzle density is, for example, set in the range of 150 to 1200 dpi. The actuator substrate 22 is, for example, a rectangular substrate formed of insulating ceramic.

[0045] The frame member 23 surrounds the periphery of the lower part of the actuator substrate 22. The opening on the lower surface of the frame member 23 is sealed by the nozzle plate 21. The space defined by the frame member 23, the actuator substrate 22, and the nozzle plate 21 forms a common ink chamber 26 (261, 262). The common ink chamber 26 has two common ink chambers 261, 262 with the actuator substrate 22 interposed therebetween. One common ink chamber 261 communicates with the ink supply port 27 and serves as an ink supply path for supplying ink to the plurality of pressure chambers 5. The ink supply port 27 is connected to Figure 1It is connected to the ink supply pressure adjusting device 321. Another common ink chamber 262 communicates with an opening portion similar to the ink supply port 27, which is not shown in the figure, that is, an ink discharge port, and forms an ink discharge path for discharging ink from the plurality of pressure chambers 5. When circulating and supplying ink, the ink discharge port is connected to the ink supply pressure adjusting device 321 via the ink discharge pipe 29.

[0046] As Figure 3 and Figure 4 shown, a plurality of pressure chambers 5 and air chambers 51 are formed to be alternately arranged on the surface of the actuator substrate 22 located in the common ink chamber 26 (261, 262). The pressure chamber 5 and the air chamber 51 are separated by a piezoelectric member 6 (61, 62) serving as a side wall. The piezoelectric member 6 (61, 62) is a piezoelectric body such as a piezoelectric element. The pressure chamber 5 and the air chamber 51 are formed on the surface of the actuator substrate 22 by grooves obtained by cutting out rectangular shapes from two piezoelectric members 61, 62 laminated in the Z direction along the third direction in the Y direction. The two piezoelectric members 61, 62 are laminated in directions opposite to the polarization directions (taking the relative direction as an example). Each pressure chamber 5 communicates with each nozzle 20 one-to-one. The air chamber 51 is located on both sides of the pressure chamber 5.

[0047] Furthermore, on both side surfaces of the actuator substrate 22, a pair of cover members 67 forming the side walls on both sides in the Y direction of the air chamber 51 are respectively provided. The air chamber 51 is separated from the common ink chamber 26 (261, 262) by the cover member 67. A groove-shaped opening 68 corresponding to the shape of the pressure chamber 5 is formed in the cover member 67 so that the pressure chamber 5 communicates with the left and right common ink chambers 261, 262. The opening 68 of the cover member 67 is adjusted to be narrower than the cross section of the pressure chamber 5, thereby braking the vibration of the ink entering and exiting between the common ink chamber 26 (261, 262) and the pressure chamber 5. The opening 68 of the cover member 67 on the common ink chamber 261 side is the ink supply port, and the opening 68 of the cover member 67 on the common ink chamber 262 side is the ink discharge port. Ink is supplied or discharged to the pressure chamber 5 via the ink supply port and the ink discharge port. As an example, Figure 3 the cover member 67 formed of a plate material is illustrated, but the cover member 67 can be formed of resin, a plate material, etc., for example. Moreover, it can also be set that the cover member 67 only fills the portions of the side walls on both sides in the Y direction of the air chamber 51.

[0048] As Figure 4As shown, the individual electrode 63 is integrally formed on the bottom surface in the Z direction and both side surfaces in the X direction of the pressure chamber 5. The common electrode 64 is integrally formed on the bottom surface in the Z direction and both side surfaces in the Y direction of the air chamber 51. The individual electrodes 63 of the respective pressure chambers 5 are respectively connected to the individual wirings 65. The common electrodes 64 of the respective air chambers 51 are commonly connected to the common wiring 66. The individual electrode 63, the common electrode 64, the individual wiring 65, and the common wiring 66 are formed of, for example, a nickel thin film and are covered with, for example, an insulating layer (not shown) or the like for insulation.

[0049] The connection point of the individual electrode 63 and the individual wiring 65 is the individual terminal of the actuator 8. The individual terminals of the actuator 8 are respectively connected to the drive driver D (i.e., the drive circuit) of the drive IC 31 via the individual wirings 65. The power supplies of the drive voltages V1, V2, and ground (GND) are connected to the drive driver D. On the other hand, the connection point of the common electrode 64 and the common wiring 66 is the common terminal of the actuator 8. The common terminals of the respective actuators 8 are commonly connected to, for example, ground (GND) or a common potential of a predetermined constant voltage. The drive driver D of each drive channel (#1ch, #2ch,... #nch) respectively applies a drive voltage to the individual terminals of each actuator 8 and independently drives each actuator 8. With this structure, in the actuator 8 to which the drive voltage is applied, an electric field is applied in a direction crossing (desirably orthogonal) the polarization axis of the piezoelectric members 6 (61, 62), and the piezoelectric members 6 (61, 62) that form the side walls in the X direction of the pressure chamber 5 are deformed symmetrically in the X direction in a shear mode.

[0050] That is, the pressure chamber 5 is formed to be sandwiched by a pair of columnar actuators 8 using the piezoelectric members 6 (61, 62). By applying a potential difference to the two walls of the columnar actuator 8, that is, the inner wall and the outer wall of the pressure chamber 5, and charging the actuator 8, the actuator 8 is deformed. As a result, the volume of the pressure chamber 5 changes, and thus, the ink pressure in the pressure chamber 5 changes. By adjusting the magnitude and timing of this change, ink is ejected from the nozzle 20.

[0051] In Figure 5 an example of the drive waveform is shown. Figure 5The driving waveform (DPR waveform) is a multi-drop driving waveform that drops three drops of ink in one driving cycle. Before the ink ejection operation, this driving waveform applies voltage Vb to the individual terminals of the actuator 8 in advance. Then, various potentials are applied to the individual terminals of the actuator 8 as driving signals, that is, voltage Va is applied from time t1 to time t2, voltage Vc is applied from time t2 to time t3, voltage Va is applied from time t3 to time t4, voltage Vb is applied from time t4 to time t5, voltage Va is applied from time t5 to time t6, voltage Vb is applied from time t6 to time t7, voltage Vc is applied from time t7 to time t8, and voltage Vb is applied at time t8. Voltage Va is, for example, 0V and is supplied by the Figure 4 GND. Voltages Vb and Vc are positive-potential voltages and are supplied by the power supplies V2 and V1 of Figure 4 respectively. Va < Vb < Vc. The common terminals of each actuator 8 are, for example, commonly connected to the ground (GND) at 0V. As an alternative to connecting the common terminal of the actuator 8 to GND, for example, it can also be set such that the common terminal of the actuator 8 is connected to the power supply V2 of voltage Vb to give a predetermined potential to the common terminal.

[0052] The periods from time t1 to time t2, from time t2 to time t3, from time t3 to time t4, from time t4 to time t5, from time t5 to time t6, from time t6 to time t7, and from time t7 to time t8 are, for example, set to be each 1 / 2 of the pressure vibration period of the head 2. That is, the basic pulse width of the driving waveform for ejecting ink is the same as 1 / 2 of the pressure vibration period of the head 2. When the pressure vibration period of the head 2 is, for example, 4 μs, the period from time t1 to time t2 as the basic pulse width is 2 μs.

[0053] As shown in Figure 6 (b), for the actuator 8 to which voltage Vb is applied to the individual terminals before the ink ejection operation, the piezoelectric members 6 (61, 62) on both sides of the pressure chamber 5 deform inward in a shear mode, and the volume inside the pressure chamber 5 shrinks. Then, as shown in Figure 6 (a), for the actuator 8 to which voltage Va is applied to the individual terminals at time t1, the piezoelectric members 6 (61, 62) that have deformed in a shear mode return to their original state, and the volume inside the pressure chamber 5 expands relatively from the state of Figure 6 (b), thereby supplying ink into the pressure chamber 5. As shown in Figure 6As shown in (c) thereof, for the actuator 8 to which the voltage Vc is applied to the individual terminal at the next moment t2, the piezoelectric members 6 (61, 62) are deformed inwardly in the shear mode respectively, whereby the volume in the pressure chamber 5 contracts. The pressure of the ink increases due to this series of volume changes in the pressure chamber 5, and the first drop of ink is ejected from the nozzle 20.

[0054] Next, for the actuator 8 to which the voltage Va is applied to the individual terminal at the moment t3, the volume in the pressure chamber 5 expands from Figure 6 the state of (c) thereof to Figure 6 the state of (a) thereof. By applying the voltage Vb at the moment t4, the volume in the pressure chamber 5 contracts to Figure 6 the state of (b) thereof, thereby ejecting the second drop of ink. Next, for the actuator 8 to which the voltage Va is applied to the individual terminal at the moment t5, the volume in the pressure chamber 5 expands from Figure 6 the state of (b) thereof to Figure 6 the state of (a) thereof. By applying the voltage Vb at the moment t6, the volume in the pressure chamber 5 contracts to Figure 6 the state of (b) thereof, thereby ejecting the third drop of ink.

[0055] Then, for the actuator 8 to which the voltage Vc is applied to the individual terminal at the moment t7, the volume in the pressure chamber 5 contracts to Figure 6 the state of (c) thereof. By applying the voltage Vb at the moment t8, the volume of the contracted pressure chamber 5 is restored to Figure 6 the state of (b) thereof. The surplus vibration is attenuated by this contraction and restoration. As an alternative to connecting the common terminal of the actuator 8 to the GND, in the case where the common terminal of the actuator 8 is connected to another predetermined potential, the shape of the actuator 8 is offset by an amount corresponding to the deformation amount corresponding to the predetermined potential. However, since the pressure of the ink applied to the pressure chamber 5 is determined by the relative change degree of the volume of the pressure chamber 5 with respect to that before the application of the pressure, even if the common terminal of the actuator 8 is connected to another predetermined potential as an alternative to connecting the common terminal of the actuator 8 to the GND, the above-described behavior of the ink does not change. Regarding the potential of the common terminal of the actuator 8, it is sufficient to select a place that is advantageous in terms of the characteristics of the actuator 8.

[0056] In the present embodiment, a plurality of delay amounts for staggering the timing of applying the drive waveform to the actuator 8 are set, and the delay amounts are allocated so as to be in a predetermined arrangement in the arrangement direction of the nozzles 20 arranged in a row. Figure 7 As an example, nine different delay amounts are set for nine delay resources (Delay 1 to 9). Figure 8 Using Figure 5 the waveform diagram to represent the timing stagger caused by Figure 7 the delay amount.

[0057] As Figure 7 and Figure 8 shown, there are nine mutually different delay amounts, a first group with smaller delay amounts and a second group with larger delay amounts. The grouping is performed according to the setting of the main delay amount. The main delay amount is preferably equal to the basic pulse width of the drive waveform. As already described, the basic pulse width of the drive waveform is usually set to 1 / 2 of the pressure vibration period of head 2. As an example, 1 / 2 of the pressure vibration period of head 2 is 2 μs.

[0058] In Figure 7 and Figure 8 's example, the main delay amounts of the odd-numbered delay resources (delay 1, 3, 5, 7, 9) among the nine delay resources (delay 1 to 9) are set to a delay amount of, for example, 0 μs in the first group. The main delay amounts of the even-numbered delay resources (delay 2, 4, 6, 8) are set to a delay amount of, for example, 2 μs in the second group. Therefore, when the nine delay resources are arranged in numerical order as Figure 7 shown, the first group with smaller delay amounts and the second group with larger delay amounts are arranged in an alternating manner. It should be noted that the delay amount is, for example, a value when the printing trigger starting from inkjet head 100 is used as the reference timing. However, the reference timing is not limited to the printing trigger. Even if the reference timing is changed, the relationship of the delay amounts between the drive channels that can suppress crosstalk will be maintained.

[0059] The delay amounts of the first group and the second group are all mutually different within the group. The delay amounts within the group are staggered by setting mutually different sub delay amounts. That is, the delay amount set for each delay resource (delay 1 to 9) is the delay amount obtained by adding the sub delay amount to the main delay amount. The sub delay amount is provided to disperse the charging or discharging operation timing in order to avoid electrical faults such as voltage drops caused by the temporary concentration of current in the common wiring 66 etc. when charging and discharging a large number of channels simultaneously, that is, electrical crosstalk. From the viewpoint of avoiding electrical crosstalk, regarding the sub delay amount, it is desirable to configure with an interval of 0.05 μs to 0.1 μs or more open, however, from the viewpoint of avoiding mechanical crosstalk, it is desirable to be set to such an extent that the delay difference from the adjacent channels does not deviate significantly from 2 μs set by the main delay amount. As an example, when the main delay amount is set to 1 / 2 of the pressure vibration period of head 2 (for example, 2 μs), it is set to 1 / 4 or less of it. In Figure 7 and Figure 8 's example, the sub delay amount is set in the range of 0.02 μs to 0.38 μs. In addition, for each group, the sub delay amount is also set in such a way that the delay amount increases monotonically in the order of the delay resource numbers.

[0060] Among the thus-set delay amounts, Delay 1 is 0.02 μs, Delay 2 is 2.04 μs, Delay 3 is 0.10 μs, Delay 4 is 2.16 μs, Delay 5 is 0.20 μs, Delay 6 is 2.26 μs, Delay 7 is 0.30 μs, Delay 8 is 2.36 μs, and Delay 9 is 0.38 μs.

[0061] Figure 9 This is an example of the drive circuit 9 having a delay amount setting unit capable of setting a plurality of delay amounts. The drive circuit 9 has the following structure: it sets a plurality of delay amounts, assigns the set delay amounts to each drive channel (1ch, 2ch,..., nch), and can start generating a drive waveform with the assigned delay amount. The drive circuit 9 is included in the drive IC 31, for example. In the following description, an example of assigning Figure 7 the plurality of delay amounts to each drive channel and generating Figure 5 the drive waveform is described. However, this circuit structure can also be applied to other drive waveforms and other delay amounts.

[0062] As Figure 9 shown, the drive circuit 9 includes a waveform generation circuit 91 and a waveform distribution circuit 92. The waveform generation circuit 91 and the waveform distribution circuit 92 are an example of the delay amount setting unit. The waveform generation circuit 91 includes a plurality of delay circuits 93, a delay amount setting memory 94, a plurality of drive waveform generation circuits 95, and a drive waveform setting memory 96. The plurality of delay circuits 93 and the plurality of drive waveform generation circuits 95 are connected in series respectively. The pairs of the delay circuit 93 and the drive waveform generation circuit 95 are set to nine groups. That is, they correspond to nine delay resources (Delay 1 to 9).

[0063] In the delay amount setting memory 94, the set values of a plurality of delay amounts are stored. That is, Figure 7 the information of the delay amounts is stored in the delay amount setting memory 94. The set values of the delay amounts stored in the delay amount setting memory 94 can be changed. For example, since there is also a case where the basic vibration period of the ink in the pressure chamber 5 and the pressure vibration period of the head 2 change according to the type of ink, for example, the delay amount is set from the firmware of the inkjet printer 10. Or, it can also be set, for example, during the manufacturing process of the inkjet head 100.

[0064] In the drive waveform setting memory 96, the information of the Figure 5 drive waveform shown is stored. However, the type of the drive waveform stored in the drive waveform setting memory 96 is not limited to one. It can also be set to pre-store a variety of drive waveforms and be able to select any drive waveform from them.

[0065] The waveform distribution circuit 92 includes a selector 97 and a drive waveform selection memory 98. As an example, a "distribution model" that periodically repeats the distribution of a plurality of delay amounts in the arrangement direction of the nozzles 20 arranged in a line may be stored in the drive waveform selection memory 98. As Figure 10 shown in an example, the distribution model P distributes delays 1, 2, 3, 4, 5, 6, 7, 8, 9 in ascending order according to the numbers of the drive channels (ch) corresponding to the arrangement direction of the nozzles 20, and then distributes delays 8, 7, 6, 5, 4, 3, 2 in descending order. Under the distribution model P, this sixteen-step repetition is also applied to the 17th ch and subsequent drive channels. That is, in Figure 10 this example, with one cycle of the distribution model P as a distribution period, the distribution model P is periodically repeated in the arrangement direction of the nozzles 20. The number of distributions in one cycle of the distribution model P is set to an even number (for example, sixteen), and the number of delay resources (delays 1 to 9) is one more than half of the number of distributions in one cycle. Thus, even when the distribution model P is repeated, the same value does not continue in the sub-delay amounts described later.

[0066] The selector 97 of the drive circuit 9 is, for example, a sixteen-channel "9-to-1" selector. The selector 97 is respectively connected to the output terminals of the respective drive waveform generation circuits 95. Moreover, the 16ch output terminals of the selector 97 are respectively connected to the respective drive channels via switches 99. The drive channels are grouped in sets of eight drive channels, and two sets of drive channel groups (a total of sixteen drive channels) form one area. For ease of drawing, two areas, area 1 and area 2, are illustrated, but it may also be composed of three or more areas. And, a plurality of drive channels share the same channel of the selector 97 among a plurality of areas, so that, for example, the drive channel (1ch) of area 1 and the drive channel (17ch) of area 2 become the same channel of the selector 97. The number of drive channels in one area is equal to the number of distributions in one cycle of the above distribution model P. And, the number of the sixteen channels of the selector 97 is also equal to the number of distributions in one cycle of the distribution model P.

[0067] The switch 99 switches and controls whether to apply the drive waveform from the selector 97 to the drive channel. The switch 99 performs an on-off operation according to a signal from the print data buffer 90. It is also possible to locally turn on the drive waveform according to a signal from the print data buffer 90 and change the number of droplets ejected. For example, the drive IC 31 includes a print data buffer 90.

[0068] In the above-mentioned driving circuit 9, after a printing trigger is given to the delay circuit 93, each delay circuit 93 starts each driving waveform generation circuit 95 after waiting for its respective delay amount to pass. Each driving waveform generation circuit 95 outputs the driving waveform stored in the driving waveform setting memory 96. Therefore, the start timing of the generation of the driving waveforms is staggered by the delay amounts set in Delays 1 to 9.

[0069] Nine driving waveforms with different delay amounts output from each driving waveform generation circuit 95 are given to the selector 97. The selector 97 distributes the nine driving waveforms to sixteen driving channels in each area (Area 1, Area 2... Area n) according to the allocation model P stored in the driving waveform selection memory 98, for example. Thus, as Figure 10 shown, it is possible to set the delay amount for all the driving channels. It should be noted that the relative delay with the adjacent driving channel in front, the absolute value of the relative delay with the adjacent driving channel in front, and the front and back average of the absolute value of the relative delay will be described later. Figure 10 will be described later.

[0070] Each driving waveform assigned to each driving channel by the selector 97 is given to each switch 99. When the switch 99 is turned on, the driving waveform is given to the actuator 8 of that driving channel. The actuator 8 to which the driving waveform is given is driven to eject ink. On the other hand, when the switch 99 is turned off, the driving waveform is not given to the driving channel. What determines whether the switch 99 is turned on or off is the print data. The switch 99 turns on / off the switch 99 of each driving channel based on the print data sent to the print data buffer 90. That is, it controls whether ink is ejected from the nozzles 20 of each driving channel.

[0071] In Figure 10 the example, in the first group (Delays 1, 3, 5, 7, 9) with a smaller delay amount and the second group (Delays 2, 4, 6, 8) with a larger delay amount among the delay amounts assigned to each driving channel by the waveform distribution circuit 92, they are alternately arranged in the order of the numbers of the driving channels corresponding to the arrangement direction of the nozzles 20. As Figure 7 shown, each group is set with sub-delay amounts such that the delay amounts monotonically increase in the order of the numbers of the delay resources (Delays 1 to 9), and based on the allocation model P, Delays 1, 2, 3, 4, 5, 6, 7, 8, 9 are allocated in ascending order, and then Delays 8, 7, 6, 5, 4, 3, 2 are allocated in descending order. Therefore, the delay amounts of each group monotonically increase in half of the allocation cycle (1ch to 16ch) along the arrangement direction of the nozzles 20 and monotonically decrease in the remaining half of the area.

[0072] Moreover, in Figure 10In the example, the delay amounts of 10ch and 8ch, 11ch and 7ch, 12ch and 6ch, 13ch and 5ch, 14ch and 4ch, 15ch and 3ch, 16ch and 2ch are the same respectively. Thus, the delay resource savings required to obtain a delay distribution of sixteen steps is nine types. To effectively prevent crosstalk, it is desirable to increase the number of delay amounts. However, since the delay resources require relatively large logic circuit resources, it is thus desirable to minimize the number of delay resources as much as possible. In the present embodiment, a waveform allocation circuit 92 that maps a limited number (nine types) of delay resources is provided to effectively prevent crosstalk. It should be noted that in Figure 10 the example, the delay amounts of seven groups are the same, but as long as the delay amounts of at least one group are equal, the number of delay resources can be saved accordingly.

[0073] The relationship of the delay amounts of each drive channel allocated with an amount of about two cycles is as shown in the Figure 11 chart. Each drive channel can be separated from the two adjacent drive channels by about 2 μs. Since this 2 μs is equal to the basic pulse width of the drive waveform, the two adjacent drive channels, for example, their pressure chambers 5 are driven in opposite directions during ink ejection, and as a result, the deterioration of the print quality caused by mechanical crosstalk can be suppressed. A deviation from 2 μs may cause the mechanical crosstalk to deteriorate, so the delay amount is finely adjusted so that the mechanical crosstalk does not deteriorate.

[0074] Here, Figure 10 the relative delay with the front adjacent drive channel described is the delay difference between a certain drive channel (this drive channel) and the drive channel with the previous number when focusing on a certain drive channel. Regarding the relative delay with the front adjacent drive channel, since the drive channels with odd numbers are negative values, in Figure 10 the absolute value of the front-back average for obtaining the absolute value of the relative delay is also shown. The front-back average of the absolute value of the relative delay refers to the average of the absolute value of the relative delay between the drive channel with the next number and the front adjacent drive channel and the absolute value of the relative delay between this drive channel and the front adjacent drive channel.

[0075] As a preferred example, in the case of the allocation of the delay amounts shown in Figure 10 among the absolute values of the relative delays with the front adjacent drive channels, the delays larger than the target delay amount, such as 2 μs, and the delays smaller than the target delay amount are alternately arranged, and their average dominates the influence of crosstalk on this drive channel. If the absolute values of the relative delays between each drive channel and the front adjacent drive channel are plotted with the drive channel number as the horizontal axis, it is the Figure 12 chart. In Figure 12In the graph, the front and back averages of the absolute value of the relative delay are also plotted. Since mechanical crosstalk is affected by both the adjacent drive channels in front and the adjacent drive channels in the back, its average dominates the mechanical crosstalk. That is, in order to minimize the mechanical crosstalk as much as possible, it is preferable that the front and back averages of the absolute value of the relative delay are close to 2 μs of the target delay amount. However, if the front and back averages of the absolute value of the relative delay of all drive channels are made to coincide with 2 μs as the target delay amount, the number of simultaneous operations will become too large, and thus even if mechanical crosstalk can be avoided, electrical crosstalk cannot be avoided. Therefore, in this embodiment, by setting an allowable range in which the front and back averages of the absolute value of the relative delay are within 2 μs ± 0.02 μs, both avoidance of mechanical crosstalk and avoidance of electrical crosstalk are achieved simultaneously. It is clear from Figure 12 that if the delay amount assignment shown in Figure 10 is set, the front and back averages of the absolute value of the relative delay of all drive channels can be converged within the range of 2 μs ± 0.02 μs.

[0076] However, if the absolute value of the relative delay with the adjacent drive channel in front continuously exceeds and falls below 2 μs of the target delay amount directly, the delay amount will continue to increase (for details, refer to the comparative example described later). Therefore, the phase of the change in the delay amount is reversed midway to prevent the delay amount from becoming too large. Specifically, in the 9ch drive channel, the delay amount is set relatively large to make the absolute value of the relative delay with the adjacent drive channel in front close to the target delay amount ( Figure 12 point a), and in the adjacent 10ch drive channel, the absolute value of the relative delay with the adjacent drive channel in front is made the same as that of the 9ch drive channel and lower than the target delay amount ( Figure 12 point b), thereby turning back the change in the delay amount.

[0077] Furthermore, in the 17ch drive channel, the delay amount is set small to make the absolute value of the relative delay with the adjacent drive channel in front close to the target delay amount ( Figure 12 point c), and in the adjacent 18ch drive channel, the absolute value of the relative delay with the adjacent drive channel in front is set to be the same as that of the Figure 17 ch and exceed the target delay amount ( Figure 12 point d), thereby turning back the change in the delay amount again.

[0078] Similarly, in the 25ch drive channel, the delay amount is set relatively large to make the absolute value of the relative delay with the adjacent drive channel in front close to the target delay amount ( Figure 12 point e), and in the adjacent 26ch drive channel, the absolute value of the relative delay with the adjacent drive channel in front is made the same as that of the 25ch drive channel and lower than the target delay amount ( Figure 12At the f point), thereby reversing the change in the delay amount. By this repetition, it is possible to prevent the delay amount from continuously increasing in the order of the drive channel numbers. The number of delay resources is also sufficient with nine, and the waveform distribution circuit 92 can also distribute the delay amount through a repetition of sixteen steps. In Figure 12 In the example of, although the phases of the changes are reversed at the center and both ends of the sixteen steps corresponding to one cycle of the delay amount distribution cycle, it is also possible to reverse the phase at least once or more within one cycle of the delay amount distribution cycle.

[0079] Next, Figure 10 The setting of the delay amount of is divided into a first group and a second group and plotted as Figure 13 . It should be noted that Figure 13 The front delay difference of refers to the delay difference from the drive channel with the previous number when focusing on a certain drive channel. The rear delay difference refers to the delay difference from the drive channel with the next number. The average is the average of the front delay difference and the rear delay difference. Since the nozzles 20 are arranged in a row, the front delay difference and the rear delay difference respectively show the delay amounts with respect to two adjacent drive channels in the arrangement direction of the nozzles 20. Since the first group and the second group are alternately distributed, adjacent drive channels are in different groups from this drive channel.

[0080] Figure 13 In (a) of, a graph showing the front delay difference, the rear delay difference, and the average of the first group is plotted. The first group is the odd-numbered drive channels with the main delay amount set to 0 μs. As Figure 13 Shown in (a) of, since the 1ch drive channel is an end channel, there is no front delay difference. In the drive channels of 3ch, 5ch, and 7ch, the absolute value of the front delay difference is less than the target delay amount, while the absolute value of the rear delay difference is greater than the target delay amount. In the 9ch drive channel, the absolute values of the front delay difference and the rear delay difference are equal again. In the drive channels of 11ch, 13ch, and 15ch, it is reversed, the absolute value of the front delay difference is larger than the target delay amount, and the absolute value of the rear delay difference is smaller than the target delay amount. In the 17ch drive channel, the absolute values of the front delay difference and the rear delay difference are equal again. In the drive channels of 19ch, 21ch, and 23ch, it is reversed, the absolute value of the front delay difference is smaller than the target delay amount, and the absolute value of the rear delay difference is larger than the target delay amount. In the 25ch drive channel, the absolute values of the front delay difference and the rear delay difference are equal again. In the drive channels of 27ch, 29ch, and 31ch, it is reversed, the absolute value of the front delay difference is larger than the target delay amount, and the absolute value of the rear delay difference is smaller than the target delay amount. In the 33ch drive channel, the absolute values of the front delay difference and the rear delay difference are equal again. The same arrangement is repeated in the odd-numbered drive channels of 35ch and later.

[0081] That is, within the first group, the settings that periodically replace such that the absolute value of the delay difference from the adjacent driving channel ahead is greater than the target delay amount and the absolute value of the delay difference from the adjacent driving channel behind is less than the target delay amount, and the settings that make the absolute value of the delay difference from the adjacent driving channel ahead less than the target delay amount and the absolute value of the delay difference from the adjacent driving channel behind greater than the target delay amount are alternately used. By repeating this replacement, it is possible to prevent the delay amount from continuously increasing in the order of the driving channel numbers within the group. It is also sufficient that the number of delay resources is nine, and the waveform distribution circuit 92 can also distribute the delay amount through 16 steps of repetition. Furthermore, within the group, the average of the absolute value of the front delay difference and the absolute value of the rear delay difference also converges within 2 μs ± 0.02 μs as the allowable range, and it is possible to minimize mechanical crosstalk.

[0082] Figure 13 In (b) of , a graph showing the front delay difference, rear delay difference, and average of the second group is drawn. The second group is the even-numbered driving channels with the main delay amount set to 2 μs. As Figure 13 shown in (b) of Figure 13 , in the driving channels of 2ch, 4ch, 6ch, and 8ch, the front delay difference is greater than the target delay amount, and the rear delay difference is less than the target delay amount. In the driving channels of 10ch, 12ch, 14ch, and 16ch, it is reversed, the front delay difference is less than the target delay amount, and the rear delay difference is greater than the target delay amount. In the driving channels of 18ch, 20ch, 22ch, and 24ch, it is reversed again, the front delay difference is greater than the target delay amount, and the rear delay difference is less than the target delay amount. In the driving channels of 26ch, 28ch, 30ch, and 32ch, it is reversed again, the front delay difference is less than the target delay amount, and the rear delay difference is greater than the target delay amount. This arrangement is also repeated in the even-numbered driving channels of 34ch and later.

[0083] That is, similar to the first group, within the second group, the settings that periodically replace such that the delay difference from the adjacent driving channel ahead is greater than the target delay amount and the delay difference from the adjacent driving channel behind is less than the target delay amount, and the settings that make the delay difference from the adjacent driving channel ahead less than the target delay amount and the delay difference from the adjacent driving channel behind greater than the target delay amount are alternately used. By repeating this replacement, similar to the first group, it is possible to prevent the delay amount from continuously increasing in the order of the driving channel numbers within the group. Furthermore, within each group, the average of the absolute value of the front delay difference and the absolute value of the rear delay difference also converges within -2 μs ± 0.02 μs as the allowable range, and it is possible to minimize mechanical crosstalk.

[0084] That is, in order to minimize mechanical crosstalk, it is sufficient to set the average of the absolute values of the delay amounts of two adjacent driving channels to converge within a predetermined range. In Figure 10In the example, the delay amount of each drive channel is assigned in such a way that the average of the absolute values of the delay amounts of two adjacent drive channels is within 2.0 μs ± 0.02 μs. Thus, since the average of the absolute values of the delay amounts between adjacent drive channels (the average of the absolute values of the front delay difference and the rear delay difference) is approximately maintained at 2 μs (the basic pulse width of the drive waveform), as a result, the influence of mechanical crosstalk can be avoided.

[0085] In addition, the sub-delay amount between drive channels for one cycle of the allocation period is as Figure 14 shown. Figure 14 The odd channels 1, 3, 5, 7, 9, …… 17, …… are the first group, and 0 μs is assigned as the main delay amount. Figure 14 The even channels 2, 4, 6, 8, …… 16, …… are the second group, and 2 μs is assigned as the main delay amount. The delay amount of each channel is the sum of the main delay amount and the sub-delay amount. The sub-delay amount is allocated in a 16-channel cycle, monotonically increasing in channels 1 to 9, which is half of it, and monotonically decreasing in channels 9 to 17. Even if only focusing on this in the odd channels of the first group, it also monotonically increases in channels 1, 3, 5, 7, 9 in the first half of the cycle and monotonically decreases in channels 9, 11, 13, 15, 17 in the second half of the cycle. Even if only focusing on this in the even channels of the second group, it also monotonically increases in channels 2, 4, 6, 8, 10 in the first half of the cycle and monotonically decreases in channels 10, 12, 14, 16 in the second half of the cycle. Since within the first group of odd channels or the second group of even channels, the sub-delay amount can be dispersed to the same value and does not appear more than three times at intervals of 0.08 μs to 0.1 μs between drive channels during the allocation period, even if multiple drive channels are driven within the same drive cycle, the simultaneous drive number will be 1 / 8 or less, and the influence of electrical crosstalk caused by current concentration on the common wiring 66 can be suppressed. In addition, as described above, since the number of allocations for one cycle of the allocation model P is set to an even number and the number of delay resources is set to an odd number that is one more than half of the number of allocations for one cycle, even if the sub-delay amount is repeatedly allocated, the same sub-delay amount is not continuous, which is beneficial for preventing electrical crosstalk.

[0086] The case where the phase of the delay amount is not inverted is used as Figure 10 a comparative example of the setting of the delay amount of Figure 15 is described. The example is set as follows: the target delay amount is set to 2 μs, and the absolute values of the relative delays with the adjacent drive channels in front alternate between 2.05 μs and 1.95 μs. In this case, as Figure 16 shown, since the average of the absolute values of the relative delays before and after is 2 μs, mechanical crosstalk can be avoided, and the delay amount is staggered by 0.1 μs successively in the order of the drive channel numbers, so electrical crosstalk can also be avoided. However, asFigure 17 As shown, the delay amount continues to increase in the order of the drive channel numbers. Therefore, additional measures such as arranging the head 2 obliquely are required to correct the misalignment caused by the delay amount. In addition, the larger the number of drive channels, the larger the amount of delay resources required, and correspondingly, the larger the circuit scale. In contrast, as an alternative to accurately setting the delay amounts before and after to 2 μs, an allowable range within 2 μs ± 0.02 μs is set in Figure 10 , and the phase of the change in the delay amount is reversed midway, whereby it is not necessary to arrange the head 2 obliquely, and an increase in the circuit scale can be suppressed.

[0087] According to the above-described embodiment, the influence of crosstalk received from the surrounding drive channels can be suppressed, and stable ejection of ink can be performed.

[0088] In Figure 18 and Figure 19 , other examples of the drive waveforms applied to the actuator 8 are shown. Figure 18 The drive waveform of Figure 18 is a drive waveform for ejecting ink once in one drive cycle. The drive waveform of

[0089] For the actuator 8 that applies a negative potential voltage (-V) to a single terminal at time t1, the piezoelectric components 6 (61, 62) on both sides of the pressure chamber 5 deform outward in a shear mode respectively, and the volume of the pressure chamber 5 expands, thereby supplying ink into the pressure chamber 5. For the actuator 8 that makes the potential of the single terminal grounded (GND) at the next time t2, the volume of the expanded pressure chamber 5 returns to its original state. That is, it contracts relatively. Thus, by making the volume of the pressure chamber 5 contract at the end of 1 / 2 of the pressure vibration cycle, the pressure of the ink in the pressure chamber 5 increases, and the ink is ejected from the nozzle 20. For the actuator 8 that applies a positive potential voltage (V) to a single terminal at the next time t3, the piezoelectric components 6 (61, 62) deform inward respectively, and the volume of the pressure chamber 5 contracts. Then, by making the potential of the single terminal grounded (GND) at time t4, the volume of the contracted pressure chamber 5 returns. The residual vibration is attenuated by this contraction and restoration.

[0090] Figure 19 The drive waveform of is a drive waveform of single-pulse pull ejection. The period from time t1 to t2 is set to 1 / 2 of the pressure vibration period of the head 2 (for example, 2 μs) as the basic pulse width. First, a bias voltage is applied to the single terminal of the actuator 8, and it is set to the drive voltage V0 (for example, 0 V) at time t1, thereby expanding the pressure chamber 5. Then, the ink is ejected by applying a drive voltage V2 of an intermediate potential at time t2 to contract the pressure chamber 5. Then, the residual vibration is attenuated by applying a drive voltage V1 at time t3 to contract the pressure chamber 5. Figure 19 The drive waveform of Figure 19 is a drive waveform of pull ejection, but it can also be push ejection, push-pull ejection, etc. Of course, the drive waveforms applicable to this embodiment are not limited to Figure 5 , Figure 18 , Figure 19 the drive waveforms of Figure 5 , Figure 18 , Figure 19 .

[0091] It should be noted that the inkjet head 100 is not limited to the shear mode type actuator 8 in which the pressure chamber 5 and the air chamber 51 are alternately arranged. For example, it can also be configured such that both the nozzle 20 and the actuator 8 are arranged in multiple numbers on the surface of the nozzle plate 21. It can also be other drop-on-demand / piezoelectric type actuators 8. In addition, the actuator 8 can also be a laminated piezoelectric actuator formed by alternately laminating piezoelectric components and internal electrodes.

[0092] In the above embodiment, the inkjet head 100 of the inkjet printer 10 is described as an example of a liquid ejection head. However, the liquid ejection head can also be a modeling material ejection head of a 3D printer or a sample ejection head of a dispensing device.

[0093] The embodiments of the present invention are presented only by way of example and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments or their modifications are included in the scope or gist of the invention and are included in the invention described in the claims and its equivalents.

[0094] Description of Reference Numerals

[0095] 10: Inkjet printer; 100 to 103: Inkjet heads; 2: Head; 20: Nozzle; 5: Pressure chamber; 51: Air chamber; 8: Actuator; 9: Drive circuit; 91: Waveform generation circuit; 92: Waveform distribution circuit; 93: Delay circuit; 94: Delay amount setting memory; 95: Drive waveform generation circuit; 96: Drive waveform setting memory; 97: Selector; 98: Drive waveform selection memory; 99: Switch.

Claims

1. A liquid ejection head, characterized in that: have: A plurality of drive channels, each of which has a nozzle and an actuator, wherein the actuator corresponds to the nozzle; and The delay amount setting unit sets the delay amount of the drive waveform applied to the actuator for each of the plurality of drive channels that arrange the nozzles in a row. In the arrangement direction of the nozzles, the relative delay amount of each of the drive channels relative to the front adjacent drive channel alternately takes a value larger than a target delay amount and a value smaller than the target delay amount, and then, any one of the values ​​larger than the target delay amount and the value smaller than the target delay amount is made close to the target delay amount, and the phase of the change in the delay amount is reversed.

2. The liquid ejection head according to claim 1, wherein: The phase of the change in the delay amount is reversed by causing a value close to the target delay amount and larger than the target delay amount or a value smaller than the target delay amount to continue twice in the arrangement direction of the nozzles.

3. The liquid ejection head according to claim 1 or 2, characterized in that: In setting the delay amount, a plurality of the delay amounts are periodically allocated to a plurality of the drive channels that arrange the nozzles in a row, and a phase of a change in the delay amount is inverted at least once in one cycle of the allocation period.

4. The liquid ejection head according to claim 1 or 2, characterized in that: The phase reversal of the change in the delay amount is reversed at a cycle such that the relative delay amount of each of the driving channels with respect to the preceding adjacent driving channel converges within a predetermined range with respect to the target delay amount.

5. The liquid ejection head according to claim 3, wherein: The phase reversal of the change in the delay amount is reversed at a cycle such that the relative delay amount of each of the driving channels with respect to the preceding adjacent driving channel converges within a predetermined range with respect to the target delay amount.

6. A liquid ejection head, characterized in that: have: A plurality of drive channels, each of which has a nozzle and an actuator, wherein the actuator corresponds to the nozzle; and The delay amount setting unit sets the delay amount of the drive waveform applied to the actuator for each of the plurality of drive channels that arrange the nozzles in a row. The delay amount includes a first group having a small delay amount and a second group having a large delay amount, and the first group and the second group are alternately allocated in the arrangement direction of the nozzles. With respect to the absolute value of the delay difference between the drive channels of other groups adjacent to the front and the rear, within each of the groups, the setting in which the absolute value of the delay difference with the front is greater than the target delay amount and the absolute value of the delay difference with the rear is less than the target delay amount, and the setting in which the absolute value of the delay difference with the front is less than the target delay amount and the absolute value of the delay difference with the rear is greater than the target delay amount are periodically replaced in the arrangement direction of the nozzles.

7. The liquid ejection head according to claim 6, wherein: The delay amounts of the first group and the second group are different from each other within the groups.

8. The liquid ejection head according to claim 6 or 7, characterized in that: The average of the absolute values ​​of the delay differences between the driving channels of other groups adjacent to the front and the rear converges within a predetermined range.

9. The liquid ejection head according to claim 6 or 7, characterized in that: In setting the delay amount, multiple delay amounts are periodically allocated to the multiple drive channels that arrange the nozzles in a row, and the delay amount of each group increases monotonically along the arrangement direction of the nozzles in an area of ​​half of the allocation period, and decreases monotonically along the arrangement direction of the nozzles in the remaining half of the area.

10. The liquid ejection head according to claim 8, wherein: In setting the delay amount, multiple delay amounts are periodically allocated to the multiple drive channels that arrange the nozzles in a row, and the delay amount of each group increases monotonically along the arrangement direction of the nozzles in an area of ​​half of the allocation period, and decreases monotonically along the arrangement direction of the nozzles in the remaining half of the area.

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