Liquid jet head driving method and liquid jet apparatus

Abstract

To provide a technique for improving jet efficiency of a liquid jet head.SOLUTION: A liquid jet head includes nozzles for jetting liquid, first and second pressure chambers communicating with the nozzles, a first driving element for changing pressures of the first pressure chamber, and a second driving element for changing pressures of the second pressure chamber. A first channel length of a channel from the first pressure chamber to the nozzles is shorter than a second channel length of a channel from the second pressure chamber to the nozzles. A driving method of a liquid jet head drives at least the first and second driving elements and thereby jets liquid from the nozzles, and driving timing of the second driving element is quicker than driving timing of the first driving element.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a method for driving a liquid ejection head and a liquid ejection apparatus. [Background technology]

[0002] Patent Document 1 discloses a liquid ejection head in which four pressure chambers are provided on both sides of a nozzle, and flow paths from each of the four pressure chambers to the nozzle are joined near the nozzle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-155768 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventionally, sufficient consideration has not been given to drive control in the case of using a liquid ejection head that uses a plurality of pressure chambers and ejects liquid from one nozzle. [Means for solving the problem]

[0005] A first aspect of the present disclosure is a method for driving a liquid jet head. The liquid jet head includes a nozzle for ejecting liquid, first and second pressure chambers communicating with the nozzle, a first drive element for changing the pressure in the first pressure chamber, and a second drive element for changing the pressure in the second pressure chamber. A first flow path length of a flow path from the first pressure chamber to the nozzle is shorter than a second flow path length of a flow path from the second pressure chamber to the nozzle. This method for driving a liquid jet head ejects liquid from the nozzle by driving at least the first and second drive elements, and the drive timing of the second drive element is earlier than the drive timing of the first drive element. In one mode of the first aspect, the liquid ejection head further comprises third and fourth pressure chambers, communicating flow paths connected to the nozzles and communicating with the first to fourth pressure chambers, a first common liquid chamber communicating with the first and second pressure chambers, a second common liquid chamber communicating with the third and fourth pressure chambers, a third drive element that changes the pressure of the third pressure chamber, and a fourth drive element that changes the pressure of the fourth pressure chamber, wherein a fourth flow path length of the flow path from the fourth pressure chamber to the nozzle is shorter than a third flow path length of the flow path from the third pressure chamber to the nozzle, and liquid is ejected from the nozzle by driving at least the first to fourth drive elements, and the drive timing of the third drive element is earlier than the drive timing of the fourth drive element. In another aspect of the first aspect, the magnitude of the pressure change in the liquid in the second pressure chamber caused by driving the second drive element is greater than the magnitude of the pressure change in the liquid in the first pressure chamber caused by driving the first drive element.

[0006] A second aspect of the present disclosure is a method for driving a liquid jet head. The liquid jet head includes a nozzle for ejecting liquid, first and second pressure chambers communicating with the nozzle, a first drive element for changing the pressure in the first pressure chamber, and a second drive element for changing the pressure in the second pressure chamber. A first flow path length of a flow path from the first pressure chamber to the nozzle is shorter than a second flow path length of a flow path from the second pressure chamber to the nozzle. This method for driving a liquid jet head ejects liquid from the nozzle by driving at least the first and second drive elements, and a magnitude of a pressure change in the liquid in the second pressure chamber caused by driving the second drive element is greater than a magnitude of a pressure change in the liquid in the first pressure chamber caused by driving the first drive element.

[0007] A third aspect of the present disclosure is a liquid ejection device including a liquid ejection head and a control unit that controls an ejection operation of the liquid ejection head. The liquid ejection head includes a nozzle that ejects liquid, first and second pressure chambers that communicate with the nozzle, a first drive element that changes the pressure in the first pressure chamber, and a second drive element that changes the pressure in the second pressure chamber, wherein a first flow path length of a flow path from the first pressure chamber to the nozzle is shorter than a second flow path length of a flow path from the second pressure chamber to the nozzle. The control unit ejects liquid from the nozzle by driving at least the first and second drive elements, and the drive timing of the second drive element is earlier than the drive timing of the first drive element. In one mode of the third aspect, the liquid ejection head further comprises third and fourth pressure chambers, a communicating flow path connected to the nozzle and communicating with the first to fourth pressure chambers, a first common liquid chamber communicating with the first and second pressure chambers, a second common liquid chamber communicating with the third and fourth pressure chambers, a third drive element that changes the pressure of the third pressure chamber, and a fourth drive element that changes the pressure of the fourth pressure chamber, wherein a fourth flow path length of the flow path from the fourth pressure chamber to the nozzle is shorter than a third flow path length of the flow path from the third pressure chamber to the nozzle, and liquid is ejected from the nozzle by driving at least the first to fourth drive elements, and the drive timing of the third drive element is earlier than the drive timing of the fourth drive element. In another aspect of the third aspect, the magnitude of the pressure change in the liquid in the second pressure chamber caused by driving the second drive element is greater than the magnitude of the pressure change in the liquid in the first pressure chamber caused by driving the first drive element.

[0008] A fourth aspect of the present disclosure is a liquid ejection device including a liquid ejection head and a control unit that controls an ejection operation of the liquid ejection head. The liquid ejection head includes a nozzle that ejects liquid, first and second pressure chambers that communicate with the nozzle, a first drive element that changes the pressure in the first pressure chamber, and a second drive element that changes the pressure in the second pressure chamber, wherein a first flow path length of a flow path from the first pressure chamber to the nozzle is shorter than a second flow path length of a flow path from the second pressure chamber to the nozzle. The control unit ejects liquid from the nozzle by driving at least the first and second drive elements, and a magnitude of a pressure change in the liquid in the second pressure chamber caused by driving the second drive element is greater than a magnitude of a pressure change in the liquid in the first pressure chamber caused by driving the first drive element. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram illustrating a configuration of a liquid ejecting apparatus according to an embodiment. [Figure 2] FIG. [Figure 3] FIG. 3 is a cross-sectional view showing the cross section III-III of FIG. 2. [Figure 4] 4 is a diagram showing a part of the flow paths for three nozzles and the first and second common liquid chambers as viewed from the bottom of FIG. 3. FIG. [Figure 5] 4 is a diagram showing a part of a flow path for one nozzle as seen from the bottom of FIG. 3. FIG. [Figure 6] FIG. 6 is an enlarged view of the flow path in FIG. 5. [Figure 7] FIG. 7 is a cross-sectional view showing the VII-VII cross section of FIG. [Figure 8] FIG. 3 is an explanatory diagram showing a head driving function of a control unit in the first embodiment. [Figure 9] 4 is a timing chart showing the relationship between a common drive signal and a drive pulse. [Figure 10] 10 is a graph showing an example 1 of a driving pulse and a pressure change. [Figure 11] 10 is a graph showing Example 2 of a driving pulse. [Figure 12] 10 is a graph showing Example 3 of a driving pulse. [Figure 13]10 is a graph showing Example 4 of a driving pulse. [Figure 14] FIG. 10 is an explanatory diagram showing a head driving function of a control unit in a second embodiment. [Figure 15] FIG. 11 is an explanatory diagram showing a head driving function of a control unit in a third embodiment. [Figure 16] 10 is a graph showing an example of a driving pulse in the third embodiment. [Figure 17] FIG. 10 is an explanatory diagram showing a head driving function of a control unit in a fourth embodiment. [Figure 18] FIG. 13 is an explanatory diagram showing a head driving function of a control unit in a fifth embodiment. [Figure 19] FIG. 13 is an explanatory diagram showing a head driving function of a control unit in a sixth embodiment. [Figure 20] FIG. 20 is an explanatory diagram showing a head driving function of a control unit in the seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] A. Configuration of the First Embodiment FIG. 1 is an explanatory diagram showing the configuration of a liquid ejection device 400 according to an embodiment. The liquid ejection device 400 is an inkjet printing device that ejects ink, an example of a liquid, onto a medium PM. The composition of the ink is not particularly limited, and may be, for example, an aqueous ink in which a colorant such as a dye or pigment is dissolved in an aqueous solvent, a solvent-based ink in which a colorant is dissolved in an organic solvent, or an ultraviolet-curable ink. The liquid ejection device 400 may also eject paint as a liquid instead of ink. The liquid ejection device 400 may be equipped with a liquid storage unit 420 that stores ink. The liquid ejection device 400 performs printing by ejecting the ink in the liquid storage unit 420 toward the medium PM. The liquid ejection device 400 includes a liquid ejection head 100, a movement mechanism 430, a transport mechanism 440, a control unit 450, and a circulation mechanism 60.

[0011] The liquid jet head 100 includes a plurality of nozzles 200, and jets liquid ink supplied from a liquid storage unit 420 from the plurality of nozzles 200. Specific examples of the liquid storage unit 420 include a cartridge that is detachable from the liquid jet device 400, a bag-shaped ink pack made of flexible film, and a container such as an ink tank that can be refilled with ink. The ink jetted from the nozzles 200 lands on a medium PM, which is typically printing paper. Note that the medium M is not limited to printing paper, and may be a printing target made of any material, such as a resin film or fabric.

[0012] The movement mechanism 430 includes a loop-shaped belt 432 and a carriage 434 fixed to the belt 432. The carriage 434 holds the liquid jet head 100. The movement mechanism 430 rotates the loop-shaped belt 432 in both directions, thereby causing the liquid jet head 100 to reciprocate along the X direction.

[0013] The transport mechanism 440 transports the medium PM along the Y direction between movements of the liquid jet head 100 by the movement mechanism 430. The Y direction is a direction perpendicular to the X direction. In this embodiment, the X and Y directions are horizontal. The Z direction is a direction intersecting the X and Y directions. In this embodiment, the Z direction is a vertically downward direction. The liquid jet head 100 ejects ink along the Z direction while being transported along the X direction. The Z direction is also referred to as the "ejection direction Z." In the following description, the tip side of an arrow indicating the X direction in the figure is referred to as the +X side, and the base end side is referred to as the -X side. The tip side of an arrow indicating the Y direction in the figure is referred to as the +Y side and the base end side is referred to as the -Y side. The tip side of an arrow indicating the Z direction in the figure is referred to as the +Z side and the base end side is referred to as the -Z side.

[0014] The control unit 450 controls the ink ejection operation from the liquid ejection head 100. The control unit 450 controls the transport mechanism 440, the movement mechanism 430, and the liquid ejection head 100 to form an image on the medium PM.

[0015] FIG. 2 is a bottom view of the liquid jet head 100. The liquid jet head 100 has a plurality of nozzles 200. The plurality of nozzles 200 are formed to penetrate a nozzle plate 240 that is arranged parallel to the XY plane. The plurality of nozzles 200 are arranged linearly along the Y direction to form a nozzle row NL. The nozzle plate 240 is manufactured by processing a silicon single crystal substrate using, for example, semiconductor processing technology. As the silicon single crystal substrate, for example, a (100) silicon single crystal substrate is suitably used. The nozzle plate 240 may also be formed from a material such as stainless steel (SUS) or titanium.

[0016] FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 2. FIG. 4 is a diagram showing the flow paths for three nozzles, the first common liquid chamber 110, and a portion of the second common liquid chamber 120, as viewed from the bottom of FIG. 3. FIG. 5 is a diagram showing the flow paths for one nozzle and a portion of the common liquid chambers 110 and 120, as viewed from the bottom of FIG. 3. FIG. 6 is an enlarged view of the flow paths in FIG. 5. FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. 6. Note that FIG. 4 only shows three nozzle flow paths 130, the first common liquid chamber 110, and the second common liquid chamber 120. Note that for ease of illustration, in FIGS. 5 and 6, the communicating flow path 350 is drawn with a solid line, the pressure chamber 330 with a dotted line, the drive element 300 with a dashed line, and the common liquid chambers 110 and 120 with a dashed line. 7, the reference numerals of the various parts in the cross section at the positions of the pressure chambers 331 and 332 are followed by the reference numerals of the various parts in the cross section taken along VII-VII in FIG. 6 at the positions of the other pressure chambers 333 and 334, in parentheses.

[0017] As shown in FIG. 4, the interval Pt1 between adjacent nozzles 200, i.e., the distance between the centers of the nozzles 200 in the Y direction, is constant. Furthermore, the interval Pt2 between adjacent pressure chambers 330_L1 among the multiple pressure chambers 330_L1 that make up row L1, i.e., the distance between the centers of the pressure chambers 330_L1 in the Y direction, is constant. A similar relationship applies to row L2. Furthermore, the interval Pt2 in row L1 and the interval Pt2 in row L2 are the same, and the interval Pt2 is half the interval Pt1. Furthermore, the interval Pt2 between the pressure chambers 330 is the same as the interval between the communication holes 340 and also the same as the interval between the centers of the nozzles 200 in the Y direction.

[0018] 3, the liquid jet head 100 has a first common liquid chamber 110 to which ink is supplied, a second common liquid chamber 120 from which ink is discharged, and individual nozzle flow paths 130 that connect the first common liquid chamber 110 and the second common liquid chamber 120. The first common liquid chamber 110 and the second common liquid chamber 120 are provided in common to a plurality of nozzles 200, and the individual nozzle flow paths 130 are provided individually for each nozzle 200. Each of the common liquid chambers 110, 120 extends in the Y direction, which is the direction along the nozzle row NL. In other words, the longitudinal direction of the common liquid chambers 110, 120 is parallel to the direction in which the plurality of nozzles 200 are arranged.

[0019] The liquid jet head 100 has a row L1 of a plurality of pressure chambers 330 that communicate with the first common liquid chamber 110, and a row L2 of a plurality of pressure chambers 330 that communicate with the second common liquid chamber 120. Row L1 is formed by a plurality of pressure chambers 330 lined up in the Y direction, and row L2 is formed by a plurality of pressure chambers 330 lined up in the Y direction. Row L1 is arranged on the −X side of the nozzle row NL, and row L2 is arranged on the +X side of the nozzle row NL. Hereinafter, the plurality of pressure chambers 330 that make up row L1 will be referred to as pressure chambers 330_L1, and the plurality of pressure chambers 330 that make up row L2 will be referred to as pressure chambers 330_L2. For the driving elements 300, connection flow paths 320, and communication holes 340 described in detail below, the driving elements 300 corresponding to row L1 will be referred to as driving elements 300_L1, the driving elements 300 corresponding to row L2 will be referred to as driving elements 300_L2, the connection flow paths 320 corresponding to row L1 will be referred to as connection flow paths 320_L1, the connection flow paths 320 corresponding to row L2 will be referred to as connection flow paths 320_L2, the communication holes 340 corresponding to row L1 will be referred to as communication holes 340_L1, and the communication holes 340 corresponding to row L2 will be referred to as communication holes 340_L2.

[0020] In this embodiment, the nozzle-specific flow path 130 corresponding to one nozzle 200 includes two pressure chambers 330_L1 in row L1, two pressure chambers 330_L2 in row L2, two connecting flow paths 320_L1 corresponding to each of the two pressure chambers 330_L1, two connecting flow paths 320_L2 corresponding to each of the two pressure chambers 330_L2, two communicating holes 340_L1 corresponding to each of the two pressure chambers 330_L1, two communicating holes 340_L2 corresponding to each of the two pressure chambers 330_L2, and a communicating flow path 350. Here, the two pressure chambers 330_L1 in this row L1 will be referred to as pressure chambers 331 and 332, the two pressure chambers 330_L2 in this row L2 will be referred to as pressure chambers 333 and 334, the two connection flow paths 320_L1 will be referred to as connection flow paths 321 and 322, the two connection flow paths 320_L2 will be referred to as connection flow paths 323 and 324, the two communication holes 340_L1 will be referred to as communication holes 341 and 342, and the two communication holes 340_L2 will be referred to as communication holes 343 and 344. Furthermore, the four drive elements 300 corresponding to the pressure chambers 331 to 334, respectively, will be referred to as drive elements 301 to 304.

[0021] Each of the common liquid chambers 110, 120 can be considered to extend in the Y direction or the direction in which the adjacent pressure chambers 331, 332 are aligned, in other words, the extension direction of the row L1 of the pressure chambers 330. In this embodiment, the direction in which the adjacent pressure chambers 331, 332 are aligned is an example of the "first direction." Furthermore, the multiple nozzle-specific flow paths 130 are aligned in the Y direction along the nozzle row NL.

[0022] The lower portions of the common liquid chambers 110, 120 and the multiple nozzle-specific flow paths 130 are mainly formed by the communication plate 140. The communication plate 140 may be configured by stacking multiple plate-shaped members. A housing unit 160 and a pressure chamber substrate 250 are installed on the upper surface of the communication plate 140, i.e., the surface facing the -Z side of the communication plate 140. The pressure chamber substrate 250 is located inside the housing unit 160 in a plan view seen in the Z direction. A vibration plate 310 is located on the upper surface of the pressure chamber substrate 250, i.e., the surface facing the -Z side of the pressure chamber substrate 250. A multiple pressure chambers 330 are provided in the pressure chamber substrate 250. Each pressure chamber 330 is a space defined by the communication plate 140, the vibration plate 310, and the pressure chamber substrate 250. The pressure chamber substrate 250 is manufactured, for example, by processing a silicon single crystal substrate using semiconductor processing technology. As the silicon single crystal substrate, for example, a (110) substrate, that is, a silicon single crystal substrate whose main surface is a (110) plane, is preferably used.

[0023] The diaphragm 310 is a plate-like member that can elastically vibrate. The diaphragm 310 is a laminate including, for example, a first layer made of silicon dioxide (SiO2) and a second layer made of zirconium oxide (ZrO2). Here, another layer such as a metal oxide may be interposed between the first and second layers. Part or all of the diaphragm 310 may be integrally formed with the pressure chamber substrate 250 using the same material. For example, the diaphragm 310 and the pressure chamber substrate 250 can be integrally formed by selectively removing a portion of a plate-like member of a predetermined thickness in the thickness direction in an area corresponding to the pressure chamber 330 by etching or the like. The diaphragm 310 may also be formed from a layer of a single material.

[0024] A nozzle plate 240 is installed on the lower surface of the communicating plate 140, i.e., the surface of the communicating plate 140 facing the +Z side, and the lower ends of the first common liquid chamber 110 and the second common liquid chamber 120, i.e., the +Z side ends of the first common liquid chamber 110 and the second common liquid chamber 120, are sealed with a flexible sealing film 150 made of a resin film, a thin metal film, or the like.

[0025] A wiring board 59 is bonded to the surface of the vibration plate 310 facing the -Z side. The wiring board 59 is a mounting component on which a plurality of wires are formed for electrically connecting the control unit 450 and the liquid jet head 100. The wiring board 59 is a flexible wiring board such as an FPC (Flexible Printed Circuit) or an FFC (Flexible Flat Cable). A drive circuit 70 for driving the drive elements 300 is mounted on the wiring board 59. The drive circuit 70 supplies drive signals to each drive element 300.

[0026] A plurality of drive elements 300 are provided on the upper surface of the vibration plate 310, i.e., the surface facing the -Z side of the vibration plate 310, corresponding to each pressure chamber 330. These drive elements 300 are, for example, piezoelectric elements. A piezoelectric element is, for example, composed of a piezoelectric layer and two electrodes arranged to sandwich the piezoelectric layer. For example, when the drive elements 301 to 304, which are piezoelectric elements, vibrate, the vibrations are transmitted to the pressure chambers 331 to 334, respectively, generating pressure waves in the pressure chambers 331 to 334. Ink is ejected from the nozzles 200 by the pressure generated by the drive elements 301 to 304. When ink is ejected from the nozzles 200, it is preferable that the four drive elements 301 to 304 corresponding to the nozzles 200 are driven simultaneously and in phase. The portion of the vibration plate 310 on the surface opposite to the surface defining the first pressure chambers 331, where the first drive elements 301 are provided, is called the first vibration section 311. Similarly, the portions of the vibration plate 310 on which the second to fourth drive elements 302 to 304 are provided are called second to fourth vibrating sections 312 to 314. Note that instead of piezoelectric elements, heat generating elements that heat ink in the pressure chambers 330 may be used as the drive elements.

[0027] A circulation mechanism 60 is connected to the common liquid chambers 110, 120. The circulation mechanism 60 supplies ink to the first common liquid chamber 110 and recovers ink discharged from the second common liquid chamber 120 for re-supply to the first common liquid chamber 110. The circulation mechanism 60 has a first supply pump 61, a second supply pump 62, a storage container 63, a recovery flow path 64, and a supply flow path 65.

[0028] The first supply pump 61 is a pump that supplies ink stored in the liquid storage section 420 to the storage container 63. The storage container 63 is a sub-tank that temporarily stores ink supplied from the liquid storage section 420. The recovery flow path 64 is interposed between the second common liquid chamber 120 and the storage container 63, and is a flow path for recovering ink from the second common liquid chamber 120 to the storage container 63. The ink stored in the liquid storage section 420 is supplied to the storage container 63 from the first supply pump 61. Furthermore, ink that has been supplied from the first common liquid chamber 110 to the individual nozzle flow paths 130 but is not ejected from the nozzles 200 and is discharged from the individual nozzle flow paths 130 to the second common liquid chamber 120 is supplied to the storage container 63 via the recovery flow path 64. The second supply pump 62 is a pump that sends out ink stored in the storage container 63. The supply flow path 65 is interposed between the first common liquid chamber 110 and the storage container 63 , and is a flow path for supplying ink from the storage container 63 to the first common liquid chamber 110 .

[0029] An opening 161 at the upper end of the first common liquid chamber 110, i.e., at the end on the -Z side of the first common liquid chamber 110, is connected to a supply flow path 65 that is outside the liquid jet head 100. In other words, the opening 161 in this embodiment functions as an inlet for introducing liquid from the circulation mechanism 60. An opening 162 at the upper end of the second common liquid chamber 120, i.e., at the end on the -Z side of the second common liquid chamber 120, is connected to a recovery flow path 64 of the circulation mechanism 60 that is outside the liquid jet head 100. In other words, the opening 162 in this embodiment functions as an outlet for discharging liquid from the circulation mechanism 60.

[0030] The nozzle-specific flow path 130 has the following flow paths and spaces. In the following description, the term "connected" is used to mean directly connected. The term "communicating" is used in a broader sense to include not only direct connection but also indirect connection. <Connection channels 321 to 324> The first connection flow path 321 connects the first common liquid chamber 110 and the first pressure chamber 331 . The second connection flow path 322 connects the first common liquid chamber 110 and the second pressure chamber 332 . The third connection flow path 323 connects the second common liquid chamber 120 and the third pressure chamber 333 . The fourth connection flow path 324 connects the second common liquid chamber 120 and the fourth pressure chamber 334 . The connection flow paths 321-324 are all flow paths that extend in the Z direction and penetrate the communication plate 140. For convenience of illustration, the connection flow paths 321-324 are hatched in Figures 5 and 6. The intersection of the connection flow path 320 and the pressure chamber 330 can be considered to be part of the pressure chamber 330.

[0031] <Pressure Chambers 331-334> The first pressure chamber 331 to the fourth pressure chamber 334 are spaces that are subjected to pressure changes by the first drive element 301 to the fourth drive element 304, respectively. The first pressure chamber 331 and the second pressure chamber 332 are arranged side by side in a first direction Dr1, and the third pressure chamber 333 and the fourth pressure chamber 334 are also arranged side by side in the first direction Dr1. In this embodiment, the first direction Dr1 is parallel to the Y direction. The first pressure chamber 331 and the second pressure chamber 332, and the third pressure chamber 333 and the fourth pressure chamber 334 are arranged with a shift in a second direction Dr2 that is perpendicular to the first direction Dr1. In this embodiment, the second direction Dr2 is parallel to the X direction. Pressure waves generated in the first pressure chamber 331 to the fourth pressure chamber 334 reach the nozzle 200 and cause ink to be ejected from the nozzle 200. It is preferable that the pressure chambers 331 to 334 have the same shape. In this embodiment, the pressure chambers 331 to 334 are arranged in a staggered pattern. Each pressure chamber 330 extends in the second direction Dr2.

[0032] <Communication holes 341~344> The first to fourth communication holes 341 to 344 each extend in the Z direction and are flow paths connecting the communication flow path 350 to the first to fourth pressure chambers 331 to 334, respectively. That is, one end of each pressure chamber 330 is connected to the connection flow path 320 and the other end is connected to the communication hole 340. The first to fourth communication holes 341 to 344 are examples of the "first flow path" to "fourth flow path," respectively. Note that in FIGS. 5 and 6, the communication holes 341 to 344 are hatched for ease of illustration. The first to second communication holes 341 and 342 are arranged side by side in the first direction Dr1, and the third to fourth communication holes 343 and 344 are also arranged side by side in the first direction Dr1. 7, the first communication hole 341 and the second communication hole 342 are separated by a communication hole partition wall 145. The communication holes 341 to 344 are flow paths that extend in the same direction as the connection flow paths 321 to 324, and penetrate the communication plate 140. It is preferable that the communication holes 341 to 344 have the same shape. The portion where the communication hole 340 and the pressure chamber 330 intersect can be considered to be part of the pressure chamber 330.

[0033] <Communicating flow path 350> As shown in FIG. 3, the communication flow path 350 is a flow path that is connected to the nozzle 200 and that communicates the nozzle 200 with the first pressure chamber 331 to the fourth pressure chamber 334. The communication flow path 350 is a flow path that extends along the nozzle surface of the nozzle plate 240 on which the plurality of nozzles 200 are formed, and the nozzle 200 is provided midway along the communication flow path 350. Specifically, the communication flow path 350 extends along the X direction and is defined by the communication plate 140 and the surface of the nozzle plate 240 facing the -Z side. As shown in FIG. 6, the communication flow path 350 includes a first portion 351, a second portion 352, and a third portion 353. The first portion 351 of the communication flow path 350 is disposed at one end of the communication flow path 350 and is connected to the first communication hole 341 and the second communication hole 342. The second portion 352 of the communicating flow path 350 is disposed at the other end of the communicating flow path 350 and is connected to the third communication hole 343 and the fourth communication hole 344. The third portion 353 of the communicating flow path 350 is connected between the first portion 351 and the second portion 352. The third portion 353 has a narrower width in the first direction Dr1 than the first portion 351 and the second portion 352. In this embodiment, the width W353 of the third portion 353 in the first direction Dr1 is constant. The portions where the first to fourth communication holes 341 to 344 and the communicating flow path 350 intersect can be considered to be part of the communicating flow path 350.

[0034] The pressure waves generated in the first pressure chamber 331 and the second pressure chamber 332 join at a first joining position Pj1 located near the lower ends of the first communication hole 341 and the second communication hole 342, i.e., the +Z side ends of the first communication hole 341 and the second communication hole 342. The pressure waves generated in the third pressure chamber 333 and the fourth pressure chamber 334 join at a second joining position Pj2 located near the lower ends of the third communication hole 343 and the fourth communication hole 344, i.e., the +Z side ends of the third communication hole 343 and the fourth communication hole 344. These pressure waves act as a driving force to eject ink from the nozzle 200.

[0035] For example, a liquid having pseudoplasticity can be used as the ink. More specifically, the ink is a liquid having a shear rate of 1000 s at 25°C. -1 The viscosity is 0.01 Pa s or more and 0.2 Pa s or less when the shear rate is 0.01 s-1 Preferably, the viscosity at this time is 0.5 Pa·s or more and 50 Pa·s or less. In this embodiment, by using four pressure chambers 331-334, the cross-sectional area of ​​each flow path is reduced, and the flow rate is increased to reduce the viscosity of the ink, making it possible to use pseudoplastic liquid ink. However, because it is desirable to efficiently utilize the energy of the drive elements 301-304 from the pressure chambers 331-334 to the nozzle 200, it is undesirable to make the flow path resistance excessively high. Therefore, in this embodiment, as shown in FIG. 5, the individual flow paths leading from adjacent pressure chambers 330 to the nozzle 200 are merged early at merging positions Pj1 and Pj2, which are closer to the pressure chamber than the nozzle 200, to prevent the flow path resistance from becoming excessively high.

[0036] In this embodiment, four pressure chambers 331 to 334 are provided for one nozzle 200, but five or more pressure chambers may be provided. In either case, drive elements are provided so as to correspond to the individual pressure chambers.

[0037] The nozzle-specific flow path 130 in this embodiment can be considered to include four individual flow paths corresponding to the four drive elements 301 to 304. An "individual flow path" is a flow path that includes at least a pressure chamber 330, and one individual flow path corresponds to one drive element 300. In this embodiment, the first individual flow path can be considered to include the first connection flow path 321, the first pressure chamber 331, and the first communication hole 341. The second to fourth individual flow paths can be considered to include the first connection flow path 321, the first pressure chamber 331, and the first communication hole 341.

[0038] The liquid jet head 100 according to the first embodiment further has the following features related to the attenuation of pressure waves. <Feature F1> As shown in FIG. 6, the first merging position Pj1 is closer to the nozzle 200-side ends of the pressure chambers 331 and 332 than the nozzle 200 in a plan view in the Z direction. That is, the distance from the first merging position Pj1 to each end of the pressure chambers 331 and 332 on the nozzle 200 side is shorter than the distance from the first merging position Pj1 to the nozzle 200. Here, the "first end of the pressure chamber 331 on the nozzle 200 side" refers to the end opposite the first common liquid chamber 110, in the X direction, of both ends of the pressure chamber 331. In other words, the end on the +X side. The "second end of the pressure chamber 332 on the nozzle 200 side" refers to the end opposite the first common liquid chamber 110, in the X direction, of both ends of the pressure chamber 332. Similarly, the second merging position Pj2 is closer to the ends of the pressure chambers 333 and 334 than the nozzle 200 in a plan view in the Z direction. The "third end of the pressure chamber 333 on the nozzle 200 side" refers to the end of the pressure chamber 333 opposite the second common liquid chamber 120, in other words, the end on the -X side, of both ends of the pressure chamber 333 in the X direction. The "fourth end of the pressure chamber 334 on the nozzle 200 side" refers to the end of the pressure chamber 334 opposite the second common liquid chamber 120, in other words, the end on the -X side.

[0039] According to this feature F1, the pressure wave from the first pressure chamber 331 and the pressure wave from the second pressure chamber 332 combine near the pressure chambers 331, 332 rather than near the nozzle 200, so it is possible to prevent the pressure waves traveling from the individual pressure chambers 330 toward the nozzle 200 from being excessively attenuated, compared to the conventional example in which the pressure wave from the first pressure chamber 331 and the pressure wave from the second pressure chamber 332 combine near the nozzle 200. The same is true for the third pressure chamber 333 and the fourth pressure chamber 334.

[0040] Furthermore, according to feature F1, the proportion of the portion of the flow path from each end of the pressure chambers 331, 332 to the nozzle 200 that is common to both the pressure chambers 331, 332 can be increased compared to the conventional example. Therefore, the flow path resistance from the pressure chambers 331, 332 to the nozzle 200 can be reduced compared to the conventional example. The same is true for the third pressure chamber 333 and the fourth pressure chamber 334. As a result, pressure loss can be reduced and ejection efficiency can be improved. The effect of improving ejection efficiency is particularly significant when using high-viscosity ink such as pseudoplastic ink. On the other hand, in a configuration in which pressure waves merge near the nozzle 200, as in the conventional example, the pressure waves are significantly attenuated, reducing ejection efficiency. Furthermore, there is a risk that it may be difficult to refill the nozzle 200 with ink or that air bubbles may be trapped in the nozzle.

[0041] The first junction position Pj1 can also be considered to be the junction position of the flow path from the first pressure chamber 331 to the nozzle 200 and the flow path from the second pressure chamber 332 to the nozzle 200. Similarly, the second junction position Pj2 can also be considered to be the junction position of the flow path from the third pressure chamber 333 to the nozzle 200 and the flow path from the fourth pressure chamber 334 to the nozzle 200. As described above, in reality, liquid is supplied from the outside to the first common liquid chamber 110, is guided from the first common liquid chamber 110 to the first pressure chamber 331 and the second pressure chamber 332, and then, in the communication flow path 350, a portion of the liquid is ejected from the nozzle 200, is guided via the third pressure chamber 333 and the fourth pressure chamber 334 to the second common liquid chamber 120, and is discharged from the second common liquid chamber 120 to the outside. Therefore, the "flow path from the third pressure chamber 333 to the nozzle 200" and the "flow path from the fourth pressure chamber 334 to the nozzle 200" are both assumed to have a flow in the opposite direction to the actual flow of liquid, but it can be understood that these flow paths can be assumed regardless of the direction of the liquid.

[0042] <Feature F2> As shown in Figure 6, in a plan view in the Z direction, the first junction position Pj1 is located between the first pressure chamber 331 and the second pressure chamber 332, and the second junction position Pj2 is located between the third pressure chamber 333 and the fourth pressure chamber 334.

[0043] <Feature F3> 6, a first junction position Pj1 is located at one end of the communication flow path 350, and a second junction position Pj2 is located at the other end. According to feature F3, the pressure waves from the pressure chambers 331 and 332 join near their generation sources, and the pressure waves from the pressure chambers 333 and 334 join near their generation sources, so that attenuation of the pressure waves can be more efficiently suppressed.

[0044] <Feature F4> 6 and 7, the first junction position Pj1 is located in a first portion 351 of the communication flow path 350, and the second junction position Pj2 is located in a second portion 352 of the communication flow path 350. According to this feature F4, as shown in FIG. 7, the communication hole partition walls 145 are present between adjacent communication holes 341, 342 and between adjacent communication holes 343, 344, so that crosstalk between the pressure chambers 331, 332 and between the pressure chambers 333, 334 can be reduced.

[0045] <Feature F5> 6, the dimension L353 of the third portion 353 of the communication flow path 350 measured along the second direction Dr2 is longer than the dimension L351 of the first portion 351. In addition, the dimension L353 of the third portion 353 is longer than the dimension L352 of the second portion 352.

[0046] <Feature F6> 6, the third portion 353 of the communication flow path 350 is connected to the nozzle 200. According to the feature F6, the pressure waves from the pressure chambers 331 to 334 join together near their sources, so that the attenuation of the pressure waves can be more efficiently suppressed.

[0047] <Feature F7> 6, the width W353 of the third portion 353 of the communicating flow path 350 measured along the first direction Dr1 is smaller than the width W351 of the first portion 351. The width W353 of the third portion 353 is also smaller than the width W352 of the second portion 352. According to this feature F7, when a pseudoplastic liquid is used, by reducing the width W353 of the third portion 353, it is possible to improve the flow rate near the nozzle 200 and reduce the viscosity of the ink near the nozzle 200.

[0048] <Feature F8> 3, each of the first communication hole 341 to the fourth communication hole 344 extends in a direction intersecting with the extension direction of the communication flow path 350. That is, the longitudinal direction of each of the first communication hole 341 to the fourth communication hole 344 is a direction intersecting with the longitudinal direction of the communication flow path 350. In this embodiment, the X direction is an example of the "extension direction of the communication flow path 350", and the Z direction is an example of the "direction intersecting with the extension direction of the communication flow path 350".

[0049] It is also possible to consider the first communication hole 341 to the fourth communication hole 344 as extending in a direction intersecting the direction in which adjacent pressure chambers 330 are aligned. As can be seen from Fig. 3, the first communication hole 341 to the fourth communication hole 344 can also be considered as extending along a direction perpendicular to the surface of the nozzle plate 240. Furthermore, it is also possible to consider the first communication hole 341 to the fourth communication hole 344 as extending along the ejection direction Z.

[0050] <Feature F9> 3, in a plan view seen in the Z direction, each of the communication holes 341-344 is closer to the nozzle 200 than the connecting flow paths 321-324. In other words, the distance from each of the communication holes 341-344 to the nozzle 200 is shorter than the distance from each of the communication holes 341-344 to the connecting flow paths 321-324. According to this feature F9, the communication flow path 350 can be shortened, and flow path resistance can be reduced.

[0051] The liquid jet head 100 of the first embodiment has at least some of the above-described features F1 to F9, and therefore can combine pressure waves on the pressure chambers 331 to 334 side, rather than on the nozzle 200 side, and can prevent pressure waves traveling from the individual pressure chambers 330 toward the nozzle 200 from being excessively attenuated. Note that some or all of the above-described features may be omitted. Furthermore, a liquid jet head 100 having a configuration other than those described above may also be used.

[0052] B. Configuration and driving method of the control unit in the first embodiment Fig. 8 is an explanatory diagram showing the head driving function of the control unit 450 in the first embodiment. The upper part of Fig. 8 depicts a circuit portion related to driving the liquid jet head 100, and the lower part of Fig. 8 depicts a plurality of pressure chambers 330_1 to 330_4, the nozzle 200, and flow path lengths FL1 to FL4 from the pressure chambers 330_1 to 330_4 to the nozzle 200.

[0053] The multiple pressure chambers 330_1 to 330_4 correspond to the pressure chambers 331 to 334 shown in FIGS. 3 to 6. Furthermore, the driving elements 300_1 to 300_4 depicted in the pressure chambers 330_1 to 330_4 correspond to the driving elements 301 to 304 shown in FIGS. 3 to 6. In a plan view seen in the Z direction, the first pressure chamber 330_1 and the second pressure chamber 330_2 are arranged on one side, the -X side, of the nozzle 200, and the third pressure chamber 330_3 and the fourth pressure chamber 330_4 are arranged on the other side, the +X side, of the nozzle 200. The second pressure chamber 330_2 and the third pressure chamber 330_3 indicated by dotted lines are pressure chambers for other adjacent nozzles.

[0054] The multiple pressure chambers 330_1 to 330_4 are arranged in a staggered pattern. That is, the pressure chambers 330_1 and 330_2 arranged on one side of the nozzle 200 and the pressure chambers 330_3 and 330_4 arranged on the other side are arranged so as to be offset in a second direction Dr2 intersecting the first direction Dr1. With respect to the positions in the first direction Dr1, the first pressure chamber 330_1 is arranged between the third pressure chamber 330_3 and the fourth pressure chamber 330_4, and the fourth pressure chamber 330_4 is arranged between the first pressure chamber 330_1 and the second pressure chamber 330_2. In other words, in the first direction Dr1, the center of the first pressure chamber 330_1 is arranged between the centers of the third pressure chamber 330_3 and the fourth pressure chamber 330_4, and the center of the fourth pressure chamber 330_4 is arranged between the centers of the first pressure chamber 330_1 and the second pressure chamber 330_2.

[0055] The relative positions of the pressure chambers 330_1 to 330_4 in Fig. 8 are shown in plan view in the Z direction, but the flow path lengths FL1 to FL4 do not indicate exact lengths, but only indicate the relationship between lengths as described below. As shown in Figs. 3 to 6, the flow paths from each pressure chamber 330 to the nozzle 200 have a three-dimensionally curved configuration, and the flow path lengths FL1 to FL4 shown in Fig. 8 are lengths measured as if tracing these three-dimensional flow paths. However, the flow paths from each pressure chamber 330 to the nozzle 200 do not need to be curved three-dimensionally, and may be configured two-dimensionally.

[0056] The flow path lengths FL1 to FL4 have the following relationship. FL1 <FL2 …(1a) FL4 <FL3 …(1b) FL1=FL4 …(1c) FL2=FL3 …(1d) That is, a first flow path length FL1 of the flow path from the first pressure chamber 330_1 to the nozzle 200 is shorter than a second flow path length FL2 of the flow path from the second pressure chamber 330_2 to the nozzle 200. Furthermore, a fourth flow path length FL4 of the flow path from the fourth pressure chamber 330_4 to the nozzle 200 is shorter than a third flow path length FL3 of the flow path from the third pressure chamber 330_3 to the nozzle 200.

[0057] These flow path lengths FL1 to FL4 are lengths of the flow paths from the ends of the pressure chambers 330_1 to 330_4 to the nozzle 200, but instead, the lengths of the flow paths from the centers of the driving elements 300_1 to 300_4 to the nozzle 200 may be used as the flow path lengths FL1 to FL4. In this case as well, it is preferable that the above formulas (1a) to (1d) hold.

[0058] It is noted that the above formulas (1c) and (1d) do not necessarily have to be satisfied. In this case, it is preferable to add a third drive signal generation circuit for generating the third drive pulse DP3 and a fourth drive signal generation circuit for generating the fourth drive pulse DP4.

[0059] The control unit 450 includes a main control circuit 510, a first drive signal generation circuit 521, a second drive signal generation circuit 522, a switch circuit 530, and a decoder 540. The main control circuit 510 controls the other circuits within the control unit 450. The first drive signal generation circuit 521, the second drive signal generation circuit 522, the switch circuit 530, and the decoder 540 operate in synchronization with a timing signal Tm periodically provided by the main control circuit 510 and a clock signal (not shown). The main control circuit 510 also supplies a dot size signal Sd to the decoder 540. The dot size signal Sd is a signal that indicates the size of dots formed on the medium PM by ejecting liquid, and is generated for each dot position. The main control circuit 510, the first drive signal generation circuit 521, and the second drive signal generation circuit 522 are shared to control multiple nozzles 200. Furthermore, the switch circuit 530 and the decoder 540 are provided corresponding to each of the nozzles 200. However, the first drive signal generation circuit 521 and the second drive signal generation circuit 522 may be provided individually corresponding to each of the nozzles 200. It is preferable that some of the circuits of the control unit 450 are mounted on a carriage 434 that carries the liquid jet head 100. Furthermore, it is possible that some of the circuits of the control unit 450 are part of the liquid jet head 100, and it is particularly preferable that the switch circuit 530 is included in the drive circuit 70.

[0060] The first drive signal generation circuit 521 and the second drive signal generation circuit 522 respectively generate a first common drive signal COM1 and a second common drive signal COM2 to be given to the drive elements 300 and supply them to a switch circuit 530. The first common drive signal COM1 includes a first drive pulse DP1, and the second common drive signal COM2 includes a second drive pulse DP2. Examples of the drive pulses DP1 and DP2 will be described later. The switch circuit 530 has analog switches 531 to 534 corresponding to the plurality of drive elements 300_1 to 300_4. In this embodiment, the first common drive signal COM1 is supplied to input terminals of two analog switches 531 and 534, and the second common drive signal COM2 is supplied to input terminals of the other two analog switches 532 and 533.

[0061] The decoder 540 decodes the dot size signal Sd provided from the main control circuit 510 to generate control signals S1 to S4 that realize the dot size represented by the dot size signal Sd. These control signals S1 to S4 are binary signals and are provided to the control terminals of the analog switches 531 to 534, respectively. The analog switches 531 to 534 are turned on or off in response to the control signals S1 to S4 to supply or stop supplying drive pulses DP1 and DP2 to the drive elements 300_1 to 300_4. The third drive pulse DP3 provided to the third drive element 300_3 is the same as the second drive pulse DP2 provided to the second drive element 300_2. The fourth drive pulse DP4 provided to the fourth drive element 300_4 is the same as the first drive pulse DP1 provided to the first drive element 300_1. In addition, a third drive signal generation circuit that generates a third common drive signal including a third drive pulse DP3 and a fourth drive signal generation circuit that generates a fourth common drive signal including a fourth drive pulse DP4 may be provided.

[0062] Note that a signal with a waveform that does not directly contribute to ejection may be applied to a drive element 300 that is not being driven. A "waveform that does not directly contribute to ejection" refers to a small waveform that does not cause liquid to be ejected from a nozzle 200 even if that waveform is applied to all drive elements 300 corresponding to that nozzle 200. Such a waveform may be a micro-oscillation waveform that is applied continuously during a non-ejection period, or a dedicated waveform that is applied to drive elements 300 that are not used for ejection in accordance with the drive timing of the drive elements 300 used for ejection in order to mitigate backflow of liquid into pressure chambers 330 that are not used for ejection. In this disclosure, the term "drive pulse" refers to a signal that includes a waveform that directly contributes to ejection, rather than a signal that includes only a waveform that does not directly contribute to ejection.

[0063] 9 is a timing chart showing the relationship between the common drive signals COM1, COM2 and the drive pulses DP1, DP2. The first common drive signal COM1 is a signal in which a first drive pulse DP1 is periodically generated for each fixed unit period Tu (control period) in synchronization with a timing signal Tm. Similarly, the second common drive signal COM2 is a signal in which a second drive pulse DP2 is periodically generated for each fixed unit period Tu in synchronization with the timing signal Tm. The drive timing t1 of the first drive pulse DP1 and the drive timing t2 of the second drive pulse DP2, which are generated within one unit period Tu, are set to be offset from each other. In other words, the drive periods of the two common drive signals COM1, COM2 are set to be offset from each other.

[0064] 10 is a graph showing Example 1 of drive pulses DP1 to DP4 in the first embodiment and the resulting pressure changes Pr1, Pr2, and Prt. As described in FIG. 8, the first drive pulse DP1 is supplied to the first drive element 300_1 of the first pressure chamber 330_1 having the short flow path length FL1, and the second drive pulse DP2 is supplied to the second drive element 300_2 of the second pressure chamber 330_2 having the long flow path length FL2.

[0065] The first drive pulse DP1 has a trapezoidal waveform in which it drops almost linearly from the midpoint potential Vmid at drive timing t1, reaches a bottom potential Vd1, is held for a certain period of time, then rises almost linearly to reach a top potential Vu1, is held for a certain period of time, and then drops almost linearly again to return to the midpoint potential Vmid. The amplitude AP1 of the first drive pulse DP1 is the difference between the top potential Vu1 and the bottom potential Vd1. The potential drop portion after drive timing t1 is a portion that pulls the diaphragm 310 in the -Z direction. Furthermore, the potential rise portion, in which the potential rises from the bottom potential Vd1, is a portion that pushes the diaphragm 310 in the +Z direction. A pressure wave in the first pressure chamber 330_1 is generated in response to this potential rise portion.

[0066] The second drive pulse DP2 has the same waveform as the first drive pulse DP1 and is generated at drive timing t2, which is earlier than the drive timing t1 of the first drive pulse DP1. The midpoint potential Vmid, bottom potential Vd2, top potential Vu2, and amplitude AP2 of the second drive pulse DP2 are the same as the midpoint potential Vmid, bottom potential Vd1, top potential Vu1, and amplitude AP1 of the first drive pulse DP1, respectively. The shapes of the drive pulses DP1 and DP2 shown in Figure 10 are just examples, and drive pulses of various other shapes can be used.

[0067] The pressure changes Pr1 and Pr2 shown in the third graph of FIG. 10 individually represent the changes in internal pressure occurring at the nozzle 200 due to the pressure waves generated in the pressure chambers 330_1 and 330_2 in response to the two drive pulses DP1 and DP2. The two pressure changes Pr1 and Pr2 have approximately the same shape, but their peak heights H1 and H2 are different. The peak height H2 is smaller than the peak height H1. The pressure change Prt shown in the fourth graph of FIG. 10 represents the total change in internal pressure occurring at the nozzle 200 due to the pressure waves generated in the four pressure chambers 330_1 to 330_4 in response to the four drive pulses DP1 to DP4. The peak height Ht of the pressure change Prt is approximately four times the peak heights H1 and H2 of the pressure changes Pr1 and Pr2. In this example, the peaks of the pressure changes Pr1 and Pr2 occur at approximately the same time, so the pressure change Prt in the communication flow path 350 at the nozzle 200 can be efficiently increased. As a result, the liquid ejection efficiency can be improved.

[0068] The driving method using Example 1 of the driving pulses DP1 to DP4 shown in FIG. 10 has the following features. <Feature G1> The drive timing of the second drive element 300_2 is earlier than the drive timing of the first drive element 300_1, and the drive timing of the third drive element 300_3 is earlier than the drive timing of the fourth drive element 300_4.

[0069] The above feature G1 can also be understood as the following feature G2. <Feature G2> The timing at which the second drive pulse DP2 is applied to the second drive element 300_2 is earlier than the timing at which the first drive pulse DP1 is applied to the first drive element 300_1, and the timing at which the third drive pulse DP3 is applied to the third drive element 300_3 is earlier than the timing at which the fourth drive pulse DP4 is applied to the fourth drive element 300_4.

[0070] The timing at which each of the drive pulses DP1 to DP4 is applied to each of the drive elements 300_1 to 300_4 is preferably set so that pressure waves generated by driving the drive elements 300_1 to 300_4 increase the pressure at the position of the nozzle 200 without canceling each other out. As an example, whether or not two pressure waves generated by driving two drive elements 300_1 and 300_2 increase the pressure without canceling each other out can be determined by comparing a first liquid amount of the liquid ejected from the nozzle 200 when the two drive elements 300_1 and 300_2 are driven with a second liquid amount of the liquid ejected from the nozzle 200 when only one drive element 300_1 is driven. In other words, if the first liquid amount is equal to or less than the second liquid amount, it can be determined that the two pressure waves generated by driving the two drive elements 300_1 and 300_2 cancel each other out. On the other hand, when the first liquid amount is greater than the second liquid amount, it can be determined that the two pressure waves generated by driving the two drive elements 300_1, 300_2 increase the pressure without canceling each other out. It is preferable to adjust the timing of the drive pulses DP1, DP2 so that the first liquid amount is 1.5 times or more the second liquid amount. Furthermore, when four drive elements 300_1 to 300_4 are driven as shown in FIG. 8, it is preferable to adjust the timing of the drive pulses DP1 to DP4 so that the first liquid amount of the liquid ejected from the nozzle 200 when the four drive elements 300 are driven is three times or more the second liquid amount of the liquid ejected from the nozzle 200 when only one drive element 300_1 is driven.

[0071] Furthermore, by adjusting the drive timing of the drive pulses DP1 and DP2 so that the amount of liquid when the drive pulses DP1 and DP2 are supplied to the drive elements 300_1 to 300_4 is greater than the amount of liquid when the same drive pulse DP1 is supplied to each of the drive elements 300_1 to 300_4, it is possible to create a composite wave in which the pressure wave peaks are combined at the same timing, thereby improving the injection efficiency.

[0072] Fig. 11 is a graph showing Example 2 of the drive pulses DP1 to DP4. The only difference between Example 2 and Example 1 shown in Fig. 10 is the waveform of the second drive pulse DP2, and the first drive pulse DP1 is the same as Example 1. Note that a graph of pressure change is omitted in Fig. 11.

[0073] The driving method using the driving pulses DP1 to DP4 of Example 2 has the following features. <Feature G3> The amplitude AP2 of the second drive pulse DP2 is greater than the amplitude AP1 of the first drive pulse DP1, and the amplitude of the third drive pulse DP3 is greater than the amplitude of the fourth drive pulse DP4. For example, the lower end potential Vd2 of the second drive pulse DP2 is set lower than the lower end potential Vd1 of the first drive pulse DP1, and the upper end potential Vu2 of the second drive pulse DP2 is set higher than the upper end potential Vu1 of the first drive pulse DP1.

[0074] The reason for employing feature G3 is to eliminate the difference in attenuation of the pressure waves generated in the four pressure chambers 330_1 to 330_4 before they reach the nozzle 200, if the difference in attenuation is not negligible. In the example of FIG. 8 , the flow path lengths FL2 and FL3 from two pressure chambers 330_2 and 330_3 to the nozzle 200 are longer than the flow path lengths FL1 and FL4 from the other two pressure chambers 330_1 and 330_4 to the nozzle 200, so it is expected that the attenuation of the pressure waves generated in the two pressure chambers 330_2 and 330_3 will be large enough to not be negligible. In this case, employing feature G3 can eliminate the difference in the attenuation of the pressure waves. That is, the pressure changes generated at the nozzle 200 by the pressure waves of the four pressure chambers 330_1 to 330_4 can be made substantially the same, thereby improving the ejection efficiency. In addition, when the peak height of the pressure change occurring at the position of the nozzle 200 in response to the first drive pulse DP1 is taken as 100%, it is preferable to adjust the amplitude AP2 of the second drive pulse DP2 so that the peak height of the pressure change occurring at the position of the nozzle 200 in response to the second drive pulse DP2 falls within the range of 100±5%.

[0075] The relationship between the difference in the amount of attenuation of the pressure wave and the ejection efficiency of the liquid can be understood as follows. For example, when the same pressure change is generated in the first pressure chamber 330_1 and the second pressure chamber 330_2, which have different flow path lengths, the amplitude of the pressure wave in the second pressure chamber 330_2, which has the longer flow path length, is smaller at the position of the nozzle 200. Therefore, there is a risk that the pressure wave from the first pressure chamber 330_1 will be transmitted toward the second pressure chamber 330_2, thereby reducing the ejection efficiency. However, by generating a larger pressure change in the second pressure chamber 330_2, which has the longer flow path length, than in the first pressure chamber 330_1, it is possible to suppress the pressure wave from the first pressure chamber 330_1 from being transmitted toward the second pressure chamber 330_2, thereby improving the ejection efficiency.

[0076] The above feature G3 can also be understood as the following feature. <Feature G4> The magnitude of the pressure change in the liquid in the second pressure chamber 330_2 caused by driving the second driving element 300_2 is greater than the magnitude of the pressure change in the liquid in the first pressure chamber 330_1 caused by driving the first driving element 300_1. Similarly, the magnitude of the pressure change in the liquid in the third pressure chamber 330_3 caused by driving the third driving element 300_3 is greater than the magnitude of the pressure change in the liquid in the fourth pressure chamber 330_4 caused by driving the fourth driving element 300_4.

[0077] <Feature G5> The displacement amount of second vibrating portion 312 of diaphragm 310 shown in FIG. 3 is greater than the displacement amount of first vibrating portion 311, and the displacement amount of third vibrating portion 313 is greater than the displacement amount of fourth vibrating portion 314. Here, the displacement amount of the vibration part of the vibration plate 310 is the difference between the position when the vibration part is displaced furthest to the +Z side and the position when it is displaced furthest to the -Z side when the drive pulse DP1 or drive pulse DP2 is applied.

[0078] The driving method using Example 2 of the driving pulses DP1 and DP2 shown in FIG. 11 may be able to improve the liquid ejection efficiency more than the driving method using Example 1 shown in FIG.

[0079] 12 is a graph showing Example 3 of the drive pulses DP1 to DP4. The only difference between Example 3 and Example 1 shown in FIG. 10 is the waveform of the second drive pulse DP2, and the first drive pulse DP1 is the same as in Example 1.

[0080] The second drive pulse DP2 of Example 3 has a trapezoidal wave with a steeper slope than the first drive pulse DP1. That is, the slope θ1 of the potential rising portion of the second drive pulse DP2 is set to be steeper than the slope θ1 of the potential rising portion of the first drive pulse DP1. The amplitude AP2 of the second drive pulse DP2 is the same as the amplitude AP1 of the first drive pulse DP1. Furthermore, the bottom potential Vd2 of the second drive pulse DP2 is the same as the bottom potential Vd1 of the first drive pulse DP1, and the top potential Vu2 of the second drive pulse DP2 is the same as the top potential Vu1 of the first drive pulse DP1. The drive timing t2 of the second drive pulse DP2 is earlier than the drive timing t1 of the first drive pulse DP1.

[0081] When a piezoelectric element is used as the driving element 300, the displacement speed of the diaphragm 310 can be increased by increasing the slope θ2 of the potential rising portion of the trapezoidal wave as shown in Fig. 12. In other words, the amplitude of the pressure wave can be increased by steepening the slope θ2 of the waveform when the diaphragm 310 is pushed in the Z direction without increasing the amplitude AP2.

[0082] Note that when a trapezoidal wave is used, the larger the gradient θ2 of the potential rising portion, the earlier the vibration of the drive element 300 tends to start. Therefore, even if the drive timing t2 of the second drive pulse DP2 is set to be the same as the drive timing t1 of the first drive pulse DP1, the effective drive timing of the second drive element 300_2 can be made earlier. In consideration of this point, the drive timing t2 of the second drive pulse DP2 may be set to be the same as the drive timing t1 of the first drive pulse DP1. In this case, too, it is preferable that the drive timings t1 and t2 of the drive pulses DP1 and DP2 be set so that the pressure waves generated by driving the drive elements 300_1 and 300_2 increase the pressure at the position of the nozzle 200 without canceling each other out.

[0083] FIG. 13 is a graph showing a fourth example of drive pulses DP1 to DP4. These drive pulses DP1 to DP4 can be used when a heat generating element is used as the drive element 300 instead of a piezoelectric element. The first drive pulse DP1 is a rectangular pulse including a first pulse portion P1a as a pre-pulse, a second pulse portion P2a as a main pulse, and an off portion Poff of a predetermined length between them. The first pulse portion P1a controls the degree of film boiling of the liquid in the pressure chamber 330, and the second pulse portion P2a triggers the ejection of the liquid in a film boiling state. Therefore, the rising timing of the second pulse portion P2a is set as the ejection drive timing t1. Like the first drive pulse DP1, the second drive pulse DP2 is a rectangular pulse that includes a first pulse portion P1b as a pre-pulse, a second pulse portion P2b as a main pulse, and an off portion Poff of a predetermined length between them, and the rising timing of the second pulse portion P2b is set as the drive timing t2 for ejection.

[0084] In the drive pulses DP1 and DP2 of Example 4, increasing the pulse width of the first pulse portions P1a and P1b strengthens film boiling and increases the amount of energy. On the other hand, since the second pulse portions P2a and P2b merely trigger ejection, changing their pulse widths has little effect. Since the time width available for each ejection is usually fixed, for example, if the first pulse portion P1b of the second drive pulse DP2 is increased, the second pulse portion P2b can be shortened accordingly, so that the overall length of the second drive pulse DP2 remains constant. For example, to change the magnitude of the pressure change in the second pressure chamber 330_2, the width of the first pulse portion P1b can be increased and the width of the second pulse portion P2b can be decreased. In this case, too, it is preferable to adjust the width of the first pulse portion P1b so that the peak height of the pressure change occurring at the nozzle 200 in response to the first drive pulse DP1 falls within the range of 100±5%.

[0085] Instead of adjusting the width of the first pulse portion P1b, the amount of energy imparted to the liquid in the pressure chamber 330_2 may be increased by increasing the number of first pulse portions P1b included in one drive pulse DP2. Alternatively, as in the case of using a piezoelectric element, the amount of energy imparted to the liquid in the pressure chamber 330_2 may be increased by increasing the voltage value of the first pulse portion P1b.

[0086] The following characteristics can be understood from the examples of drive pulses shown in FIGS. <Feature G6> At least one of the timing and waveform of the drive pulses DP1 and DP2 is adjusted so that the pressure wave generated in the first pressure chamber 330_1 and the pressure wave generated in the second pressure chamber 330_2 increase the pressure at the position of the nozzle 200 without canceling each other out.

[0087] <Feature G7> The waveforms of the drive pulses DP1 and DP2 are adjusted to eliminate the difference in the amount of attenuation of the pressure wave caused by the difference in the flow path lengths FL1 and FL2. Specifically, when the peak height of the pressure change generated at the position of the nozzle 200 in response to the first drive pulse DP1 is taken as 100%, it is preferable to adjust the waveforms so that the peak height of the pressure change generated at the position of the nozzle 200 in response to the second drive pulse DP2 falls within the range of 100±5%.

[0088] According to the head driving method of the first embodiment described above, by having at least some of the above features G1 to G7, it is possible to reduce the deviation of the pressure wave caused by the difference in the flow path lengths FL1 to FL4 from the nozzle 200 to the pressure chambers 330_1 to 330_4, thereby improving the ejection efficiency.

[0089] C. Other Embodiments 14 is an explanatory diagram showing the head driving function of the control unit 450 in the second embodiment. The main difference between the second embodiment and the first embodiment described above is only the positional relationship of the multiple pressure chambers 330_1 to 330_4 in a plan view seen in the Z direction, and other device configurations and control operations are almost the same as those in the first embodiment.

[0090] 8, the multiple pressure chambers 330_1 to 330_4 are arranged in a staggered pattern, but in the second embodiment, they are not arranged in a staggered pattern. That is, the first pressure chamber 330_1 and the fourth pressure chamber 330_4 are arranged at the same position in the first direction Dr1. The second pressure chamber 330_2 and the third pressure chamber 330_3 indicated by dotted lines are pressure chambers for other adjacent nozzles. For example, the second pressure chamber 330_2 is arranged at the same position in the first direction Dr1 as the third pressure chamber 330_3 for another adjacent nozzle on the -Y side.

[0091] In this second embodiment, the formulas (1a) to (1d) described in the first embodiment also hold. Note that the drive timing and waveform shape of the drive pulses DP1 and DP2 may be adjusted in accordance with the above-mentioned features G6 and G7. The second embodiment also has substantially the same effects as the first embodiment, and can improve the liquid ejection efficiency.

[0092] 15 is an explanatory diagram showing the head driving function of the control unit 450 in the third embodiment. The main difference between the third embodiment and the first embodiment described above is that a fifth pressure chamber 330_5 and a sixth pressure chamber 330_6 are added as pressure chambers communicating with the nozzles 200, and a third drive signal generation circuit 523 is added; other device configurations and control operations are substantially the same as those in the first embodiment.

[0093] In a plan view seen in the Z direction, the fifth pressure chamber 330_5 is arranged on one side, the -X side, of the nozzle 200, similar to the first pressure chamber 330_1 and the second pressure chamber 330_2. The sixth pressure chamber 330_6 is arranged on the other side, the +X side, of the nozzle 200, similar to the third pressure chamber 330_3 and the fourth pressure chamber 330_4. The multiple pressure chambers 330_1 to 330_6 are arranged in a staggered pattern. That is, the pressure chambers 330_1, 330_2, and 330_5 arranged on one side of the nozzle 200 and the pressure chambers 330_3, 330_4, and 330_6 arranged on the other side are arranged at positions that are shifted from each other in the first direction Dr1.

[0094] In the third embodiment, the following formula is established for the flow path lengths FL1 to FL6 from the six pressure chambers 330_1 to 330_6 to the nozzle 200. FL1 <FL5<FL2 …(3a) FL4 <FL6<FL3 …(3b) FL1=FL4 …(3c) FL2=FL3 …(3d) FL5=FL6 …(3e)

[0095] The third drive signal generation circuit 523 generates a third common drive signal COM3 including drive pulses DP5 and DP6 supplied to the drive element 300_5 of the fifth pressure chamber 330_5 and the drive element 300_6 of the sixth pressure chamber 330_6. The same drive pulses DP5 and DP6 can be used. The switch circuit 530 has analog switches 531 to 536 corresponding to the plurality of drive elements 300_1 to 300_6. The decoder 540 decodes the dot size signal Sd supplied from the main control circuit 510 to generate control signals S1 to S6 that realize the dot size represented by the dot size signal Sd. These control signals S1 to S6 are supplied to the control terminals of the analog switches 531 to 536, respectively.

[0096] 16 is a graph showing drive pulses DP1 to DP6 in the third embodiment. The first drive pulse DP1 and the second drive pulse DP2 are the same as those in Example 2 of the first embodiment shown in FIG. 11. The fifth drive pulse DP5 is generated at drive timing t5, which is earlier than the drive timing t1 of the first drive pulse DP1 and later than the drive timing t2 of the second drive pulse DP2. The amplitude AP5 of the fifth drive pulse DP5 is greater than the amplitude AP1 of the first drive pulse DP1 and smaller than the amplitude AP2 of the second drive pulse DP2. The bottom potential Vd5 of the fifth drive pulse DP5 is lower than the bottom potential Vd1 of the first drive pulse DP1 and higher than the bottom potential Vd2 of the second drive pulse DP2. The top potential Vu5 of the fifth drive pulse DP5 is higher than the top potential Vu1 of the first drive pulse DP1 and lower than the top potential Vu2 of the second drive pulse DP2. However, the amplitudes AP1, AP2, and AP5 of the three types of drive pulses DP1, DP2, and DP5 may be the same. Also, the drive timing and waveform shape of the fifth drive pulse DP5 may be adjusted in accordance with the above-mentioned features G6 and G7.

[0097] The driving method of the third embodiment has the following features. <Feature G8> The drive timing of the fifth drive element 300_5 is earlier than the drive timing of the first drive element 300_1 and later than the drive timing of the second drive element 300_2. Similarly, the drive timing of the sixth drive element 300_6 is earlier than the drive timing of the fourth drive element 300_4 and later than the drive timing of the third drive element 300_3.

[0098] <Feature G9> The timing at which the fifth drive pulse DP5 is applied to the fifth drive element 300_5 is earlier than the timing at which the first drive pulse DP1 is applied to the first drive element 300_1 and later than the timing at which the second drive pulse DP2 is applied to the second drive element 300_2. Similarly, the timing at which the sixth drive pulse DP6 is applied to the sixth drive element 300_6 is earlier than the timing at which the fourth drive pulse DP4 is applied to the fourth drive element 300_4 and later than the timing at which the third drive pulse DP3 is applied to the third drive element 300_3.

[0099] <Feature G10> The amplitude AP5 of the fifth drive pulse DP5 is greater than the amplitude AP1 of the first drive pulse DP1 and less than the amplitude AP2 of the second drive pulse DP2. Similarly, the amplitude of the sixth drive pulse DP6 is greater than the amplitude of the fourth drive pulse DP4 and less than the amplitude of the third drive pulse DP3.

[0100] <Feature G11> The magnitude of the pressure change in the liquid in the fifth pressure chamber 330_5 caused by driving the fifth drive element 300_5 is larger than the magnitude of the pressure change in the liquid in the first pressure chamber 330_1 caused by driving the first drive element 300_1, and is smaller than the magnitude of the pressure change in the liquid in the second pressure chamber 330_2 caused by driving the second drive element 300_2. Similarly, the magnitude of the pressure change in the liquid in the sixth pressure chamber 330_6 caused by driving the sixth drive element 300_6 is larger than the magnitude of the pressure change in the liquid in the fourth pressure chamber 330_4 caused by driving the fourth drive element 300_4, and is smaller than the magnitude of the pressure change in the liquid in the third pressure chamber 330_3 caused by driving the third drive element 300_3.

[0101] The above-described third embodiment also has the same effects as the first and second embodiments, and can improve the liquid ejection efficiency.

[0102] Fig. 17 is an explanatory diagram showing the head driving function of the control unit 450 in the fourth embodiment. The main differences between the fourth embodiment and the above-described third embodiment are that the pressure chambers 330_1 to 330_6 are not arranged in a staggered pattern, the flow path lengths FL1 to FL6 from the pressure chambers 330_1 to 330_6 to the nozzles 200 are different from those in Fig. 15, and the third drive signal generation circuit 523 is omitted, but other device configurations and control operations are substantially the same as those in the third embodiment.

[0103] The multiple pressure chambers 330_1 to 330_6 in the fourth embodiment are not arranged in a staggered pattern, as in the second embodiment shown in Fig. 14. For example, the fifth pressure chamber 330_5 and the third pressure chamber 330_3 are arranged at the same position in the first direction Dr1. The first pressure chamber 330_1 and the fourth pressure chamber 330_4 are also arranged at the same position in the first direction Dr1, and the second pressure chamber 330_2 and the sixth pressure chamber 330_6 are also arranged at the same position in the first direction Dr1.

[0104] In the fourth embodiment, the following formula is established for the flow path lengths FL1 to FL6 from the six pressure chambers 330_1 to 330_6 to the nozzle 200. FL1 <FL2 …(4a) FL4 <FL3 …(4b) FL1=FL4 …(4d) FL2=FL3=FL5=FL6 …(4e)

[0105] In the fourth embodiment, the third drive pulse DP3, fifth drive pulse DP5, and sixth drive pulse DP6 are the same as the second drive pulse DP2. Note that the timing and waveform of the drive pulses DP1 to DP6 in the fourth embodiment may be adjusted in accordance with the above features G6 and G7.

[0106] In the fourth embodiment, the flow path length FL5 from the fifth pressure chamber 330_5 to the nozzle 200 is equal to the flow path length FL2 from the second pressure chamber 330_2 to the nozzle 200, and therefore the fifth pressure chamber 330_5 can be considered equivalent to the second pressure chamber 330_2. Furthermore, the flow path length FL6 from the sixth pressure chamber 330_6 to the nozzle 200 is equal to the flow path length FL3 from the third pressure chamber 330_3 to the nozzle 200, and therefore the sixth pressure chamber 330_6 can be considered equivalent to the third pressure chamber 330_3. In other words, the liquid jet head 100 of the fourth embodiment can be considered to have two second pressure chambers 330_2 and two third pressure chambers 330_3.

[0107] The fourth embodiment described above also has the same effect as the first embodiment, and can improve the liquid ejection efficiency.

[0108] FIG. 18 is an explanatory diagram showing the head driving function of the control unit 450 in the fifth embodiment. The main difference between the fifth embodiment and the above-described fourth embodiment is that the positional relationship between the pressure chambers 330_1, 330_2, and 330_5 arranged on one side of the nozzle 200 and the pressure chambers 330_2, 330_4, and 330_6 arranged on the other side of the nozzle 200 is shifted in the first direction Dr1 from FIG. 17; other device configurations and control operations are substantially the same as those in the fourth embodiment. In this embodiment, in the first direction Dr1, the pressure chambers 330_5 and 330_4 are in the same position, and the pressure chambers 330_1 and 330_6 are in the same position. In other words, the multiple pressure chambers 330 are not arranged in a staggered pattern. In other words, in a planar view, the nozzle 200 is located at the intersection of a line segment connecting the center of the pressure chamber 330_1 and the center of the pressure chamber 330_4, a line segment connecting the center of the pressure chamber 330_2 and the center of the pressure chamber 330_3, and a line segment connecting the center of the pressure chamber 330_5 and the center of the pressure chamber 330_6.

[0109] In the fifth embodiment, the following formula is established for the flow path lengths FL1 to FL6 from the six pressure chambers 330_1 to 330_6 to the nozzle 200. FL1 <FL2 …(5a) FL4 <FL3 …(5b) FL1=FL4=FL5=FL6 …(5c) FL2 = FL3 …(5d)

[0110] In the fifth embodiment, the fifth drive pulse DP5 and the sixth drive pulse DP6 are the same as the first drive pulse DP1. Furthermore, the drive timing and waveform shape of the drive pulses DP1 to DP6 in the fifth embodiment may be adjusted in accordance with the above features G6 and G7.

[0111] In the fifth embodiment, the flow path length FL5 from the fifth pressure chamber 330_5 to the nozzle 200 is equal to the flow path length FL1 from the first pressure chamber 330_1 to the nozzle 200, so the fifth pressure chamber 330_5 can be considered equivalent to the first pressure chamber 330_1. Furthermore, the flow path length FL6 from the sixth pressure chamber 330_6 to the nozzle 200 is equal to the flow path length FL4 from the fourth pressure chamber 330_4 to the nozzle 200, so the sixth pressure chamber 330_6 can be considered equivalent to the fourth pressure chamber 330_4. In other words, the liquid jet head 100 of the fifth embodiment can be considered to have two first pressure chambers 330_1 and two fourth pressure chambers 330_4.

[0112] The fifth embodiment described above also has the same effect as the first embodiment, and can improve the liquid ejection efficiency.

[0113] FIG. 19 is an explanatory diagram showing the head driving function of the control unit 450 in the sixth embodiment. The main differences between the sixth embodiment and the first embodiment described above are that the third pressure chamber 330_3 and the fourth pressure chamber 330_4 are omitted and that the nozzle 200 is disposed between the two pressure chambers 330_1 and 330_2. The other device configurations and control operations are substantially the same as those of the first embodiment. In a plan view seen in the Z direction, the two pressure chambers 330_1 and 330_2 extend along the X direction, with their longitudinal directions parallel to the X direction. The two pressure chambers 330_1 and 330_2 are arranged along the Y direction, which is perpendicular to the X direction. The nozzle 200 is disposed between the two pressure chambers 330_1 and 330_2.

[0114] In the sixth embodiment, as in the first embodiment, the flow path length FL1 from the first pressure chamber 330_1 to the nozzle 200 is shorter than the flow path length FL2 from the second pressure chamber 330_2 to the nozzle 200. The position of the nozzle 200 can be set to any position other than the position shown in FIG. 18 . For example, the nozzle 200 may be disposed at a position overlapping with the first pressure chamber 330_1 in a plan view seen in the Z direction. In this case, the first flow path length FL1 corresponds to approximately the flow path length of the communication hole 341 connected to the first pressure chamber 330_1, and the second flow path length FL2 corresponds to approximately the sum of the flow path length of the communication hole 342 connected to the second pressure chamber 330_2 and the flow path length of the communication flow path 350 connecting the communication hole 341 and the communication hole 342.

[0115] The sixth embodiment has the following features G12 and G13 as superordinate concepts of the features G1 and G2 of the first embodiment described above. <Feature G12> The drive timing of the second drive element 300_2 is earlier than the drive timing of the first drive element 300_1.

[0116] <Feature G13> The timing at which the second drive pulse DP2 is applied to the second drive element 300_2 is earlier than the timing at which the first drive pulse DP1 is applied to the first drive element 300_1.

[0117] As described in the first embodiment, it is preferable that the drive timings in the above features G12 and G13 are determined so that the pressure waves generated by driving the drive elements 300_1 and 300_2 reinforce each other at the position of the nozzle 200 without canceling each other out.

[0118] The drive timing and waveform shape of the drive pulses DP1 and DP2 in the sixth embodiment may also be adjusted in accordance with the above-mentioned features G6 and G7. The sixth embodiment also has the same effects as the first embodiment, and can improve the liquid ejection efficiency.

[0119] As can be understood from the first to sixth embodiments, the driving method of the liquid jet head 100 in the present disclosure can be realized as a method of ejecting liquid from the nozzle 200 by using a liquid jet head 100 having at least a first pressure chamber 330_1 and a second pressure chamber 330_2 and driving at least the first driving element 300_1 and the second driving element 300_2.

[0120] 20 is an explanatory diagram showing the head driving function of the control unit 450 in the seventh embodiment. The seventh embodiment is mainly different from the sixth embodiment in that the two pressure chambers 330_1 and 330_2 are aligned in the X direction and that the nozzle 200 is disposed between the two pressure chambers 330_1 and 330_2 in the X direction; other device configurations and control operations are substantially the same as those of the sixth embodiment. In a plan view seen in the Z direction, the two pressure chambers 330_1 and 330_2 extend along the X direction, with their longitudinal directions parallel to the X direction. Furthermore, the two pressure chambers 330_1 and 330_2 are arranged along the X direction.

[0121] In the seventh embodiment, as in the sixth embodiment, the flow path length FL1 from the first pressure chamber 330_1 to the nozzle 200 is shorter than the flow path length FL2 from the second pressure chamber 330_2 to the nozzle 200. The position of the nozzle 200 can be set to any position other than the position shown in Fig. 19. For example, as in the sixth embodiment, the nozzle 200 may be disposed at a position overlapping with the first pressure chamber 330_1 in a plan view seen in the Z direction.

[0122] The seventh embodiment also has the above-mentioned features G13 and G14, as with the sixth embodiment. The drive timing and waveform shape of the drive pulses DP1 and DP2 of the seventh embodiment may also be adjusted in accordance with the above-mentioned features G6 and G7. The seventh embodiment also has the same effects as the first embodiment, and can improve the liquid ejection efficiency.

[0123] Variation 1 In each of the above-described embodiments, a serial-type liquid ejection device 400 is exemplified, in which the carriage 434 holding the liquid ejection head 100 is reciprocated, but the present disclosure can also be applied to a line-type liquid ejection device in which a plurality of nozzles 200 are distributed across the entire width of the medium PM. In other words, the carriage holding the liquid ejection head 100 is not limited to a serial-type carriage, and may be a structure that supports the liquid ejection head 100 in a line-type manner. In this case, for example, a plurality of liquid ejection heads 100 are arranged side by side in the width direction of the medium PM, and the plurality of liquid ejection heads 100 are collectively held by a single carriage.

[0124] Variation 2 In each of the above-described embodiments, the liquid ejecting device 400 is exemplified as being equipped with the circulation mechanism 60, but the liquid ejecting device 400 does not necessarily have to be equipped with the circulation mechanism 60. That is, both of the openings 161, 162 of the housing 160 may be inlets for introducing liquid from the liquid storage section 420, and both the first common liquid chamber 110 and the second common liquid chamber 120 may be used as flow paths for supplying the liquid supplied from the liquid storage section 420 to the nozzles 200.

[0125] Variation 3 In each of the above-described embodiments, two, four, or six pressure chambers 330 are provided corresponding to one nozzle, but an odd number of pressure chambers 330, such as three, five, or seven, may be provided corresponding to one nozzle. Also, eight or more pressure chambers 330 may be provided corresponding to one nozzle.

[0126] Variation 4 In the above-described embodiments, one connection flow path 320 is connected to each of the pressure chambers 331 to 334, but a common connection flow path 320 may be provided for the pressure chambers 331 and 332 connected to the same first common liquid chamber 110. In other words, a configuration may be adopted in which one connection flow path 320 is provided corresponding to a plurality of pressure chambers 330. The same applies to the pressure chambers 333 and 334 connected to the same second common liquid chamber 120. When considering four individual flow paths corresponding to the individual pressure chambers 331 to 334 in Modification 4, for example, the first individual flow path does not include the connection flow path 320. The second to fourth individual flow paths can also be understood in a similar manner.

[0127] Variation 5 In each of the above-described embodiments, the connection flow path 320 is a flow path extending in the Z direction, but the connection flow path 320 may be a flow path extending in a direction intersecting the Z direction, or may be a flow path including both a portion extending in the Z direction and a portion extending in a direction intersecting the Z direction.

[0128] Variation 6 The liquid ejection apparatus exemplified in the above-described embodiment can be employed in various devices such as facsimile machines and copiers, as well as devices dedicated to printing. However, the uses of the liquid ejection apparatus are not limited to printing. For example, a liquid ejection apparatus that ejects a solution of a coloring material is used as a manufacturing apparatus for forming color filters for display devices such as liquid crystal display panels. Furthermore, a liquid ejection apparatus that ejects a solution of a conductive material is used as a manufacturing apparatus for forming wiring and electrodes on a wiring board. Furthermore, a liquid ejection apparatus that ejects a solution of an organic substance related to a living body is used as a manufacturing apparatus for manufacturing biochips, for example.

[0129] Other forms: The present disclosure is not limited to the above-described embodiments and can be realized in various forms without departing from the spirit thereof. For example, the present disclosure can also be realized in the following aspects. The technical features in the above embodiments corresponding to the technical features in each aspect described below can be appropriately replaced or combined to solve some or all of the problems of the present disclosure or to achieve some or all of the effects of the present disclosure. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0130] (1) A first aspect of the present disclosure is a method for driving a liquid jet head. The liquid jet head includes a nozzle for ejecting liquid, first and second pressure chambers communicating with the nozzle, a first drive element for changing the pressure in the first pressure chamber, and a second drive element for changing the pressure in the second pressure chamber. A first flow path length of a flow path from the first pressure chamber to the nozzle is shorter than a second flow path length of a flow path from the second pressure chamber to the nozzle. This method for driving a liquid jet head includes driving at least the first and second drive elements to eject liquid from the nozzle, and driving the second drive element at a timing earlier than the driving timing of the first drive element. According to this method, it is possible to reduce the deviation of the pressure wave caused by the difference in the flow path length from the nozzle to the first and second pressure chambers, and improve the ejection efficiency.

[0131] (2) In the above driving method, the liquid may be ejected from the nozzle by supplying at least a first drive pulse to the first drive element and a second drive pulse to the second drive element. The timing of applying the second drive pulse to the second drive element may be earlier than the timing of applying the first drive pulse to the first drive element.

[0132] (3) In the above driving method, the liquid jet head may further include third and fourth pressure chambers, communication flow paths connected to the nozzles and communicating with the first to fourth pressure chambers, a first common liquid chamber communicating with the first and second pressure chambers, a second common liquid chamber communicating with the third and fourth pressure chambers, a third drive element that changes the pressure of the third pressure chamber, and a fourth drive element that changes the pressure of the fourth pressure chamber. A fourth flow path length from the fourth pressure chamber to the nozzle may be shorter than a third flow path length from the third pressure chamber to the nozzle. Liquid may be jetted from the nozzles by driving at least the first to fourth drive elements, and the drive timing of the third drive element may be earlier than the drive timing of the fourth drive element. According to this method, it is possible to reduce the deviation of the pressure wave caused by the difference in the flow path length from the nozzle to the first to fourth pressure chambers, and improve the ejection efficiency.

[0133] (4) In the above driving method, liquid may be ejected from the nozzle by at least supplying a first drive pulse to the first drive element, a second drive pulse to the second drive element, a third drive pulse to the third drive element, and a fourth drive pulse to the fourth drive element. The timing at which the second drive pulse is applied to the second drive element may be earlier than the timing at which the first drive pulse is applied to the first drive element, and the timing at which the third drive pulse is applied to the third drive element may be earlier than the timing at which the fourth drive pulse is applied to the fourth drive element. The first drive pulse and the fourth drive pulse may be generated by the same first drive signal generation circuit, and the second drive pulse and the third drive pulse may be generated by the same second drive signal generation circuit.

[0134] (5) In the above driving method, the liquid jet head may further include a fifth pressure chamber communicating with the first common liquid chamber and communicating with the nozzle via the communication flow path, a sixth pressure chamber communicating with the second common liquid chamber and communicating with the nozzle via the communication flow path, a fifth drive element that changes the pressure of the fifth pressure chamber, and a sixth drive element that changes the pressure of the sixth pressure chamber. A fifth flow path length of a flow path from the fifth pressure chamber to the nozzle may be longer than the first flow path length and shorter than the second flow path length, and a sixth flow path length of a flow path from the sixth pressure chamber to the nozzle may be longer than the fourth flow path length and shorter than the third flow path length. Liquid may be ejected from the nozzle by driving the first to sixth drive elements, and a drive timing of the fifth drive element may be earlier than a drive timing of the first drive element and later than a drive timing of the second drive element. The drive timing of the sixth drive element may be earlier than the drive timing of the fourth drive element and later than the drive timing of the third drive element.

[0135] (6) In the above driving method, the magnitude of the pressure change in the liquid in the second pressure chamber caused by driving the second driving element may be greater than the magnitude of the pressure change in the liquid in the first pressure chamber caused by driving the first driving element.

[0136] (7) In the above driving method, the magnitude of the pressure change of the liquid in the second pressure chamber caused by driving the second driving element may be larger than the magnitude of the pressure change of the liquid in the first pressure chamber caused by driving the first driving element. The magnitude of the pressure change of the liquid in the third pressure chamber caused by driving the third driving element may be larger than the magnitude of the pressure change of the liquid in the fourth pressure chamber caused by driving the fourth driving element.

[0137] (8) A second aspect of the present disclosure is a method for driving a liquid jet head. The liquid jet head includes a nozzle for ejecting liquid, first and second pressure chambers communicating with the nozzle, a first drive element for changing the pressure in the first pressure chamber, and a second drive element for changing the pressure in the second pressure chamber. A first flow path length of a flow path from the first pressure chamber to the nozzle is shorter than a second flow path length of a flow path from the second pressure chamber to the nozzle. This method for driving a liquid jet head ejects liquid from the nozzle by driving at least the first and second drive elements, and a magnitude of a pressure change in the liquid in the second pressure chamber caused by driving the second drive element is greater than a magnitude of a pressure change in the liquid in the first pressure chamber caused by driving the first drive element.

[0138] (9) In the above driving method, the liquid jet head may include a vibration plate including a first vibration section having the first driving element provided on a surface opposite to a surface defining the first pressure chamber, and a second vibration section having the second driving element provided on a surface opposite to a surface defining the second pressure chamber. Each of the first and second driving elements may be a piezoelectric element, and a displacement amount of the second vibration section may be larger than a displacement amount of the first vibration section.

[0139] (10) In the above driving method, liquid may be ejected from the nozzle by at least supplying a first driving pulse to the first driving element and a second driving pulse to the second driving element, and the amplitude of the second driving pulse may be greater than the amplitude of the first driving pulse.

[0140] (11) In the above driving method, the liquid jet head may further include third and fourth pressure chambers, a communication flow path connected to the nozzle and communicating with the first to fourth pressure chambers, a first common liquid chamber communicating with the first and second pressure chambers, a second common liquid chamber communicating with the third and fourth pressure chambers, a third drive element that changes the pressure of the third pressure chamber, and a fourth drive element that changes the pressure of the fourth pressure chamber. A fourth flow path length from the fourth pressure chamber to the nozzle may be shorter than a third flow path length from the third pressure chamber to the nozzle. Liquid may be ejected from the nozzle by driving at least the first to fourth drive elements, and a magnitude of a pressure change in the liquid in the third pressure chamber caused by driving the third drive element may be larger than a magnitude of a pressure change in the liquid in the fourth pressure chamber caused by driving the fourth drive element. According to this method, for example, if the same pressure change is generated in the first pressure chamber and the second pressure chamber, which have different flow path lengths, the amplitude of the pressure wave in the second pressure chamber, which has the longer flow path length, will be smaller at the nozzle position. As a result, there is a risk that the pressure wave from the first pressure chamber will propagate into the second pressure chamber, reducing ejection efficiency. However, by generating a larger pressure change in the second pressure chamber, which has the longer flow path length, than in the first pressure chamber, it is possible to suppress the pressure wave from the first pressure chamber from propagating into the second pressure chamber, thereby improving ejection efficiency.

[0141] (12) In the above driving method, the liquid may be ejected from the nozzle by at least supplying a first drive pulse to the first drive element, a second drive pulse to the second drive element, a third drive pulse to the third drive element, and a fourth drive pulse to the fourth drive element. The amplitude of the second drive pulse may be larger than the amplitude of the first drive pulse, and the amplitude of the third drive pulse may be larger than the amplitude of the fourth drive pulse. The first drive pulse and the fourth drive pulse may be generated by the same first drive signal generation circuit, and the second drive pulse and the third drive pulse may be generated by the same second drive signal generation circuit.

[0142] (13) In the above driving method, the liquid jet head may further include a fifth pressure chamber communicating with the first common liquid chamber and communicating with the nozzle via the communicating flow path, a sixth pressure chamber communicating with the second common liquid chamber and communicating with the nozzle via the communicating flow path, a fifth drive element that changes the pressure of the fifth pressure chamber, and a sixth drive element that changes the pressure of the sixth pressure chamber. A fifth flow path length of a flow path from the fifth pressure chamber to the nozzle may be longer than the first flow path length and shorter than the second flow path length, and a sixth flow path length of a flow path from the sixth pressure chamber to the nozzle may be longer than the fourth flow path length and shorter than the third flow path length. The first to sixth drive elements may be driven to eject liquid from the nozzle, and the magnitude of the pressure change of the liquid in the fifth pressure chamber caused by driving the fifth drive element may be larger than the magnitude of the pressure change of the liquid in the first pressure chamber caused by driving the first drive element and smaller than the magnitude of the pressure change of the liquid in the second pressure chamber caused by driving the second drive element. The pressure change of the liquid in the sixth pressure chamber caused by driving the sixth drive element may be larger than the magnitude of the pressure change of the liquid in the fourth pressure chamber caused by driving the fourth drive element and smaller than the magnitude of the pressure change of the liquid in the third pressure chamber caused by driving the third drive element.

[0143] (14) In the above driving method, in a plan view, a first joining position of a first pressure wave transmitted from the first pressure chamber to the nozzle by driving the first driving element and a second pressure wave transmitted from the second pressure chamber to the nozzle by driving the second driving element may be closer to each of the ends of the first pressure chamber and the second pressure chamber than to the nozzle. In a plan view, a second joining position of a third pressure wave transmitted from the third pressure chamber to the nozzle by driving the third driving element and a fourth pressure wave transmitted from the fourth pressure chamber to the nozzle by driving the fourth driving element may be closer to each of the ends of the third pressure chamber and the fourth pressure chamber than to the nozzle.

[0144] (15) In the above driving method, the first flow path length and the fourth flow path length may be the same, and the second flow path length and the third flow path length may be the same.

[0145] (16) In the above driving method, the first pressure chamber and the second pressure chamber may be arranged side by side in a first direction, the third pressure chamber and the fourth pressure chamber may be arranged side by side in the first direction, and the first and second pressure chambers may be arranged to be shifted from the third and fourth pressure chambers in a second direction intersecting the first direction. The first pressure chamber may be arranged between the third pressure chamber and the fourth pressure chamber, and the fourth pressure chamber may be arranged between the first pressure chamber and the second pressure chamber.

[0146] (17) In the above driving method, the first common liquid chamber may be a flow path for supplying liquid to the first and second pressure chambers, and the second common liquid chamber may be a flow path for recovering liquid from the third and fourth pressure chambers.

[0147] (18) A third aspect of the present disclosure is a liquid ejection device including a liquid ejection head and a control unit that controls an ejection operation of the liquid ejection head. The liquid ejection head includes a nozzle that ejects liquid, first and second pressure chambers that communicate with the nozzle, a first drive element that changes the pressure in the first pressure chamber, and a second drive element that changes the pressure in the second pressure chamber, wherein a first flow path length of a flow path from the first pressure chamber to the nozzle is shorter than a second flow path length of a flow path from the second pressure chamber to the nozzle. The control unit ejects liquid from the nozzle by driving at least the first and second drive elements, and the drive timing of the second drive element is earlier than the drive timing of the first drive element.

[0148] (19) A fourth aspect of the present disclosure is a liquid ejection device including a liquid ejection head and a control unit that controls an ejection operation of the liquid ejection head. The liquid ejection head includes a nozzle that ejects liquid, first and second pressure chambers that communicate with the nozzle, a first drive element that changes the pressure in the first pressure chamber, and a second drive element that changes the pressure in the second pressure chamber, wherein a first flow path length of a flow path from the first pressure chamber to the nozzle is shorter than a second flow path length of a flow path from the second pressure chamber to the nozzle. The control unit ejects liquid from the nozzle by driving at least the first and second drive elements, and a magnitude of a pressure change in the liquid in the second pressure chamber caused by driving the second drive element is greater than a magnitude of a pressure change in the liquid in the first pressure chamber caused by driving the first drive element.

[0149] The present disclosure may be realized in various forms other than a liquid jet head driving method and a liquid jet device, such as a method for manufacturing a liquid jet head and a liquid jet device, a method for controlling a liquid jet head and a liquid jet device, a computer program for realizing the control method, or a non-transitory recording medium on which the computer program is recorded. [Explanation of symbols]

[0150] 54... vibration plate, 59... wiring board, 60... circulation mechanism, 61... first supply pump, 62... second supply pump, 63... storage container, 64... recovery flow path, 65... supply flow path, 70... drive circuit, 100... liquid jet head, 110... first common liquid chamber, 120... second common liquid chamber, 130... nozzle-specific flow path, 140... communication plate, 145... communication hole partition wall, 150... sealing film, 160... housing part, 161... opening, 162... opening, 200... nozzle, 240... nozzle plate, 250... pressure chamber substrate, 300, 301 to 304... drive element, 310... vibration plate, 311... first vibration part, 312... second vibration part, 313... third vibration vibrating unit, 314...fourth vibrating unit, 320, 321 to 324...connecting flow path, 330, 331 to 334...pressure chamber, 340, 341 to 344...communicating hole, 350...communicating flow path, 351...first part, 352...second part, 353...third part, 400...liquid ejection device, 420...liquid storage part, 430...moving mechanism, 432...belt, 434...carriage, 440...conveying mechanism, 450...control unit, 510...main control circuit, 521...first drive signal generating circuit, 522...second drive signal generating circuit, 523...third drive signal generating circuit, 530...switch circuit, 531 to 536...analog switches, 540...decoder

Claims

1. A nozzle for spraying a liquid; first to fourth pressure chambers communicating with the nozzle; a communication flow path connected to the nozzle and communicating with the first to fourth pressure chambers; a first common liquid chamber communicating with the first and second pressure chambers; a second common liquid chamber communicating with the third and fourth pressure chambers; a first driving element that changes the pressure in the first pressure chamber; a second driving element that changes the pressure in the second pressure chamber; a third driving element that changes the pressure in the third pressure chamber; a fourth driving element that changes the pressure in the fourth pressure chamber; Equipped with a first flow path length of a flow path from the first pressure chamber to the nozzle is shorter than a second flow path length of a flow path from the second pressure chamber to the nozzle; a fourth flow path length of a flow path from the fourth pressure chamber to the nozzle is shorter than a third flow path length of a flow path from the third pressure chamber to the nozzle; a driving method for a liquid ejection head that ejects liquid from the nozzle by driving at least the first to fourth driving elements, The drive timing of the second drive element is earlier than the drive timing of the first drive element, The drive timing of the third drive element is earlier than the drive timing of the fourth drive element. A method for driving a liquid jet head.

2. supplying at least a first drive pulse to the first drive element, a second drive pulse to the second drive element, a third drive pulse to the third drive element, and a fourth drive pulse to the fourth drive element, thereby ejecting liquid from the nozzle; The timing at which the second drive pulse is applied to the second drive element is earlier than the timing at which the first drive pulse is applied to the first drive element; the timing at which the third drive pulse is applied to the third drive element is earlier than the timing at which the fourth drive pulse is applied to the fourth drive element; the first drive pulse and the fourth drive pulse are generated by the same first drive signal generating circuit, the second drive pulse and the third drive pulse are generated by the same second drive signal generating circuit; The method for driving a liquid jet head according to claim 1 .

3. The liquid jet head includes: a fifth pressure chamber communicating with the first common liquid chamber and communicating with the nozzle via the communication flow path; a sixth pressure chamber communicating with the second common liquid chamber and communicating with the nozzle via the communication flow path; a fifth driving element that changes the pressure in the fifth pressure chamber; a sixth driving element that changes the pressure in the sixth pressure chamber; Further provided with a fifth flow path length of a flow path from the fifth pressure chamber to the nozzle is longer than the first flow path length and shorter than the second flow path length, a sixth flow path length of a flow path from the sixth pressure chamber to the nozzle is longer than the fourth flow path length and shorter than the third flow path length, Driving the first to sixth driving elements causes the liquid to be ejected from the nozzle; the drive timing of the fifth drive element is earlier than the drive timing of the first drive element and later than the drive timing of the second drive element; The drive timing of the sixth drive element is earlier than the drive timing of the fourth drive element and later than the drive timing of the third drive element. The method for driving a liquid jet head according to claim 2 .

4. a magnitude of a pressure change in the liquid in the second pressure chamber caused by driving the second driving element is larger than a magnitude of a pressure change in the liquid in the first pressure chamber caused by driving the first driving element, a magnitude of a pressure change in the liquid in the third pressure chamber caused by driving the third driving element is greater than a magnitude of a pressure change in the liquid in the fourth pressure chamber caused by driving the fourth driving element; The method for driving a liquid jet head according to claim 1 .

5. A nozzle for spraying a liquid; first and second pressure chambers communicating with the nozzle; a first driving element that changes the pressure in the first pressure chamber; a second driving element that changes the pressure in the second pressure chamber; Equipped with a first flow path length of a flow path from the first pressure chamber to the nozzle is shorter than a second flow path length of a flow path from the second pressure chamber to the nozzle; a driving method for a liquid ejecting head that ejects liquid from the nozzle by driving at least the first and second driving elements, The drive timing of the second drive element is earlier than the drive timing of the first drive element, A method for driving a liquid ejection head, characterized in that the magnitude of the pressure change in the liquid in the second pressure chamber caused by driving the second drive element is greater than the magnitude of the pressure change in the liquid in the first pressure chamber caused by driving the first drive element.

6. A nozzle for spraying a liquid; first and second pressure chambers communicating with the nozzle; a first driving element that changes the pressure in the first pressure chamber; a second driving element that changes the pressure in the second pressure chamber; Equipped with a first flow path length of a flow path from the first pressure chamber to the nozzle is shorter than a second flow path length of a flow path from the second pressure chamber to the nozzle; a driving method for a liquid ejecting head that ejects liquid from the nozzle by driving at least the first and second driving elements, a magnitude of a pressure change in the liquid in the second pressure chamber caused by driving the second driving element is greater than a magnitude of a pressure change in the liquid in the first pressure chamber caused by driving the first driving element; A method for driving a liquid jet head.

7. the liquid jet head comprises a vibration plate including a first vibration section in which the first driving element is provided on a surface opposite to a surface that defines the first pressure chamber, and a second vibration section in which the second driving element is provided on a surface opposite to a surface that defines the second pressure chamber, each of the first and second driving elements is a piezoelectric element; The displacement amount of the second vibration part is greater than the displacement amount of the first vibration part. The method for driving a liquid jet head according to claim 6 .

8. supplying at least a first drive pulse to the first drive element and a second drive pulse to the second drive element to eject liquid from the nozzle; The amplitude of the second drive pulse is greater than the amplitude of the first drive pulse. The method for driving a liquid jet head according to claim 6 or 7.

9. The liquid jet head includes: third and fourth pressure chambers; a communication flow path connected to the nozzle and communicating with the first to fourth pressure chambers; a first common liquid chamber communicating with the first and second pressure chambers; a second common liquid chamber communicating with the third and fourth pressure chambers; a third driving element that changes the pressure in the third pressure chamber; a fourth driving element that changes the pressure in the fourth pressure chamber; Further provided with a fourth flow path length of a flow path from the fourth pressure chamber to the nozzle is shorter than a third flow path length of a flow path from the third pressure chamber to the nozzle; Driving at least the first to fourth drive elements to eject liquid from the nozzle; a magnitude of a pressure change in the liquid in the third pressure chamber caused by driving the third driving element is greater than a magnitude of a pressure change in the liquid in the fourth pressure chamber caused by driving the fourth driving element; The method for driving a liquid jet head according to claim 6 .

10. supplying at least a first drive pulse to the first drive element, a second drive pulse to the second drive element, a third drive pulse to the third drive element, and a fourth drive pulse to the fourth drive element, thereby ejecting liquid from the nozzle; the amplitude of the second drive pulse is greater than the amplitude of the first drive pulse; the amplitude of the third drive pulse is greater than the amplitude of the fourth drive pulse; the first drive pulse and the fourth drive pulse are generated by the same first drive signal generating circuit, the second drive pulse and the third drive pulse are generated by the same second drive signal generating circuit; The method for driving a liquid jet head according to claim 9 .

11. The liquid jet head includes: a fifth pressure chamber communicating with the first common liquid chamber and communicating with the nozzle via the communication flow path; a sixth pressure chamber communicating with the second common liquid chamber and communicating with the nozzle via the communication flow path; a fifth driving element that changes the pressure in the fifth pressure chamber; a sixth driving element that changes the pressure in the sixth pressure chamber; Further provided with a fifth flow path length of a flow path from the fifth pressure chamber to the nozzle is longer than the first flow path length and shorter than the second flow path length, a sixth flow path length of a flow path from the sixth pressure chamber to the nozzle is longer than the fourth flow path length and shorter than the third flow path length, Driving the first to sixth driving elements causes the liquid to be ejected from the nozzle; a magnitude of a pressure change in the liquid in the fifth pressure chamber caused by driving the fifth driving element is larger than a magnitude of a pressure change in the liquid in the first pressure chamber caused by driving the first driving element, and is smaller than a magnitude of a pressure change in the liquid in the second pressure chamber caused by driving the second driving element, a pressure change in the liquid in the sixth pressure chamber caused by driving the sixth driving element is larger than a pressure change in the liquid in the fourth pressure chamber caused by driving the fourth driving element, and is smaller than a pressure change in the liquid in the third pressure chamber caused by driving the third driving element; The method for driving a liquid jet head according to claim 9 or 10.

12. in a plan view, a first joining position of a first pressure wave transmitted from the first pressure chamber to the nozzle by driving the first driving element and a second pressure wave transmitted from the second pressure chamber to the nozzle by driving the second driving element is closer to each of an end of the first pressure chamber and an end of the second pressure chamber than to the nozzle, in a plan view, a second joining position of a third pressure wave transmitted from the third pressure chamber to the nozzle by driving the third driving element and a fourth pressure wave transmitted from the fourth pressure chamber to the nozzle by driving the fourth driving element is closer to each of the ends of the third pressure chamber and the fourth pressure chamber than to the nozzle; 11. The method for driving a liquid jet head according to claim 1, 2, 4, 9, or 10.

13. the first flow path length and the fourth flow path length are the same, The second flow path length and the third flow path length are the same.

13. The method for driving a liquid jet head according to claim 1, 2, 4, 9, 10, or 12.

14. the first pressure chamber and the second pressure chamber are arranged side by side in a first direction, the third pressure chamber and the fourth pressure chamber are arranged side by side in the first direction, the first and second pressure chambers are arranged to be shifted from the third and fourth pressure chambers in a second direction intersecting the first direction, the first pressure chamber is disposed between the third pressure chamber and the fourth pressure chamber, the fourth pressure chamber is disposed between the first pressure chamber and the second pressure chamber; 14. The method for driving a liquid jet head according to claim 1, 2, 4, 9, 10, 12, or 13.

15. the first common liquid chamber is a flow path for supplying liquid to the first and second pressure chambers, the second common liquid chamber is a flow path for recovering liquid from the third and fourth pressure chambers; 15. The method for driving a liquid jet head according to claim 1, 2, 4, 9, 10, and 12 to 14.

16. A liquid ejection apparatus including a liquid ejection head and a control unit that controls an ejection operation of the liquid ejection head, The liquid jet head includes: A nozzle for spraying a liquid; first to fourth pressure chambers communicating with the nozzle; a communication flow path connected to the nozzle and communicating with the first to fourth pressure chambers; a first common liquid chamber communicating with the first and second pressure chambers; a second common liquid chamber communicating with the third and fourth pressure chambers; a first driving element that changes the pressure in the first pressure chamber; a second driving element that changes the pressure in the second pressure chamber; a third driving element that changes the pressure in the third pressure chamber; a fourth driving element that changes the pressure in the fourth pressure chamber; Equipped with a first flow path length of a flow path from the first pressure chamber to the nozzle is shorter than a second flow path length of a flow path from the second pressure chamber to the nozzle; a fourth flow path length of a flow path from the fourth pressure chamber to the nozzle is shorter than a third flow path length of a flow path from the third pressure chamber to the nozzle; The control unit Driving at least the first to fourth drive elements to eject liquid from the nozzle; The drive timing of the second drive element is earlier than the drive timing of the first drive element, The drive timing of the third drive element is earlier than the drive timing of the fourth drive element. A liquid ejection device characterized by:

17. A liquid ejection apparatus including a liquid ejection head and a control unit that controls an ejection operation of the liquid ejection head, The liquid jet head includes: A nozzle for spraying a liquid; first and second pressure chambers communicating with the nozzle; a first driving element that changes the pressure in the first pressure chamber; a second driving element that changes the pressure in the second pressure chamber; Equipped with a first flow path length of a flow path from the first pressure chamber to the nozzle is shorter than a second flow path length of a flow path from the second pressure chamber to the nozzle; The control unit Driving at least the first and second driving elements to eject liquid from the nozzle; The drive timing of the second drive element is earlier than the drive timing of the first drive element, a magnitude of a pressure change in the liquid in the second pressure chamber caused by driving the second driving element is greater than a magnitude of a pressure change in the liquid in the first pressure chamber caused by driving the first driving element; A liquid ejection device characterized by:

18. A liquid ejection apparatus including a liquid ejection head and a control unit that controls an ejection operation of the liquid ejection head, The liquid jet head includes: A nozzle for spraying a liquid; first and second pressure chambers communicating with the nozzle; a first driving element that changes the pressure in the first pressure chamber; a second driving element that changes the pressure in the second pressure chamber; Equipped with a first flow path length of a flow path from the first pressure chamber to the nozzle is shorter than a second flow path length of a flow path from the second pressure chamber to the nozzle; The control unit Driving at least the first and second driving elements to eject liquid from the nozzle; a magnitude of a pressure change in the liquid in the second pressure chamber caused by driving the second driving element is greater than a magnitude of a pressure change in the liquid in the first pressure chamber caused by driving the first driving element; A liquid ejection device characterized by:

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