Liquid dispensing device

Abstract

To realize stable discharge with high-frequency drive.SOLUTION: When drive frequency of a driving signal X is represented by f (unit: kHz), a time from fall of a main pulse Pm to rise of a cancel pulse Pc is represented by Tw (unit: μsec), and a pulse width of the cancel pulse Pc is represented by Tc (unit: μsec), the following formula (1): 50≤f≤-11.3×(Tw+Tc)+120 is established (in other words, Tw+Tc is set so that the formula (1) is established when driving at an arbitrary frequency f of 50 kHz or more).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection device that includes a nozzle, a pressure chamber that communicates with the nozzle, an actuator that applies pressure to the liquid in the pressure chamber, and a control unit that applies a drive signal to the actuator. [Background technology]

[0002] The ink ejection device (liquid ejection device) of Patent Document 1 generates a pressure wave in the ink flow path and ejects ink from the nozzle by applying a drive signal to an actuator that has a total of three pulse signals, two ejection pulse signals and one non-ejection pulse signal, in response to a print command per dot (within one ejection period). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-280463 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, in liquid ejection devices, from the viewpoint of high-speed recording, there has been a demand for actuators to be driven at high frequencies. If the frequency of the drive signal is about 20 kHz, the drive signal as described in Patent Document 1 can stably eject liquid from the nozzles. However, if the frequency of the drive signal is further increased, the ejection may become unstable with the drive signal as described in Patent Document 1.

[0005] An object of the present invention is to provide a liquid ejection device that can achieve stable ejection by high frequency driving. [Means for solving the problem]

[0006] The liquid ejection device according to the present invention comprises a nozzle, a pressure chamber communicating with the nozzle, an actuator that applies pressure to the liquid in the pressure chamber, and a control unit that applies a drive signal to the actuator, wherein the drive signal includes, within one ejection cycle for forming one dot, a rectangular main pulse and a rectangular cancel pulse that is applied after the main pulse and has a pulse width smaller than that of the main pulse, and is a push-pull method in which the volume of the pressure chamber is increased from a predetermined volume and then decreased to below the predetermined volume, thereby ejecting liquid from the nozzle, and is characterized in that when the drive frequency of the drive signal is f (unit: kHz), the time from the falling edge of the main pulse to the rising edge of the cancel pulse is Tw (unit: μsec), and the pulse width of the cancel pulse is Tc (unit: μsec), the following equation (1) holds: 50≦f≦-11.3×(Tw+Tc)+120 (1) [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic plan view of a printer 1 according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of a head 3 included in the printer 1. [Figure 3] 3 is a cross-sectional view of the head 3 taken along line III-III in FIG. 2. [Figure 4] 2 is a block diagram showing the electrical configuration of the printer 1. FIG. [Figure 5] 10 is a graph showing a drive signal X supplied to an actuator 22x by a driver IC 5D of the head 3. [Figure 6] 10 is a graph showing the relationship between Tw+Tc and the limit frequency Fl related to the cancel pulse Pc included in the drive signal X. [Figure 7] 10 is a graph showing the relationship between the total time Tt and the limit frequency Fl for three pulses included in the drive signal X. [Figure 8] 10 is a graph showing the displacement of the meniscus in response to application of a drive signal X. [Figure 9]10 is a graph showing the relationship between the product of the maximum displacement Q of the meniscus that occurs after application of a cancel pulse Pc and the time Tq from the start of application of the drive signal to the time when the maximum displacement Q occurs, and the limit frequency Fl. DETAILED DESCRIPTION OF THE INVENTION

[0008] As shown in Figure 1, a printer 1 according to one embodiment of the present invention includes a carriage 2 that can move in a scanning direction (a direction perpendicular to the vertical direction) while holding a head 3, a platen 6 that supports paper P below the head 3 and carriage 2, a transport mechanism 4 that transports paper P in a transport direction (a direction perpendicular to the scanning direction and the vertical direction), and a control unit 100. A plurality of nozzles 31 are formed on the underside of the head 3. In this embodiment, the resolution of an image formed by ink ejected from the nozzles 31 is 1200 dpi or higher. The plurality of nozzles 31 are aligned at a density of 50 dpi or higher in the transport direction (the direction of relative movement between paper P, which is a recording medium, and the plurality of nozzles 31).

[0009] The carriage 2 is supported by a pair of guide rails 7 and 8 extending in the scanning direction. The carriage 2 moves in the scanning direction along the guide rails 7 and 8 when a carriage motor 2M (see FIG. 4) is driven under the control of the control unit 100.

[0010] The transport mechanism 4 includes two pairs of rollers 11 and 12 arranged at positions sandwiching the platen 6 and the carriage 2 in the transport direction. The roller pairs 11 and 12 rotate while sandwiching the paper P by driving a transport motor 4M (see FIG. 4) under the control of the control unit 100. This causes the paper P to be transported in the transport direction.

[0011] As shown in Figures 2 and 3, the head 3 includes a flow path member 21, an actuator member 22 arranged on the surface 21a of the flow path member 21, and a sealing member 23 arranged between the flow path member 21 and the actuator member 22.

[0012] 3, the flow path member 21 is made up of nine plates 41 to 49. The plates 41 to 49 are stacked one on top of the other in the vertical direction (thickness direction of each plate 41 to 49). The plates 41 to 49 are made of a metal material (stainless steel, etc.).

[0013] A plurality of pressure chambers 30 are formed in the plate 41. A plurality of nozzles 31 are formed in the plate 49. A front surface 41a of the plate 41 corresponds to the front surface 21a of the flow path member 21, and a back surface 49b of the plate 49 corresponds to the back surface 21b of the flow path member 21. A plurality of pressure chambers 30 open in the front surface 21a, and a plurality of nozzles 31 open in the back surface 21b.

[0014] Four common flow paths 29 (see FIG. 2) are formed in the plates 44 to 48. A communication flow path 35 is formed in the plates 42 and 43 for each pressure chamber 30, connecting the pressure chamber 30 to the common flow path 29. A connection flow path 36 is formed in the plates 42 to 48 for each pressure chamber 30, connecting the pressure chamber 30 to the nozzle 31.

[0015] As shown in FIG. 2, the four common flow paths 29 each extend in the transport direction and are aligned in the scanning direction. A common flow path 29 is provided for each pressure chamber row made up of a plurality of pressure chambers 30 aligned in the transport direction. The four pressure chamber rows are aligned in the scanning direction. Ink is supplied from each common flow path 29 to the plurality of pressure chambers 30 belonging to each pressure chamber row via a communication flow path 35 (see FIG. 3). Then, as will be described later, when each actuator 22x of the actuator member 22 deforms, pressure is applied to the ink in the pressure chambers 30, and the ink is ejected from the nozzle 31 through the connection flow path 36.

[0016] In this way, the flow path member 21 is formed with four common flow paths 29 and a plurality of individual flow paths 32 (flow paths including pressure chambers 30 and nozzles 31, and flow paths extending from the outlet of the common flow path 29 to the nozzles 31 via the communicating flow path 35, the pressure chambers 30 and the connecting flow path 36) that are connected to each common flow path 29.

[0017] As shown in FIG. 2, two supply ports 27 and two return ports 28 are formed on the surface 21a of the flow path member 21. The two supply ports 27 are arranged upstream of the four common flow paths 29 in the transport direction. The two return ports 28 are arranged downstream of the four common flow paths 29 in the transport direction. The supply ports 27 and the return ports 28 are each connected to the ink tank 9 (see FIG. 1) via a tube or the like. Each supply port 27 is connected to two common flow paths 29 adjacent to each other in the scanning direction, and supplies ink from the ink tank 9 to the two common flow paths 29. Each return port 28 is connected to two common flow paths 29 adjacent to each other in the scanning direction, and returns ink from the two common flow paths 29 to the ink tank 9.

[0018] The actuator member 22 is disposed at the center of the surface 21a of the flow path member 21, and does not cover the supply ports 27 or the return ports 28, but covers all of the pressure chambers 30 that open to the surface 21a. As shown in Fig. 3, the actuator member 22 includes two piezoelectric layers 61, 62, a common electrode 52, and a plurality of individual electrodes 51. The piezoelectric layers 61, 62 and the common electrode 52 define the outer shape of the actuator member 22 shown in Fig. 2, and have a rectangular shape that is slightly smaller than the flow path member 21 when viewed in the vertical direction. On the other hand, the individual electrodes 51 are provided for each pressure chamber 30, and overlap each of the pressure chambers 30 in the vertical direction.

[0019] The individual electrodes 51 and the common electrode 52 are electrically connected to a driver IC 5D (see FIG. 4). The driver IC 5D maintains the potential of the common electrode 52 at ground potential while varying the potential of the individual electrodes 51 between a predetermined drive potential and ground potential. Specifically, the driver IC 5D generates a drive signal based on a control signal from the control unit 100 and supplies the drive signal to the individual electrodes 51. As a result, the potential of the individual electrodes 51 varies between the predetermined drive potential and ground potential. At this time, the portion of the piezoelectric layer 61 sandwiched between the individual electrodes 51 and the common electrode 52 (the actuator 22x) contracts in the planar direction due to the piezoelectric transverse effect. Accordingly, the portions of the actuator member 22 and the sealing member 23 that vertically overlap the pressure chambers 30 deform convexly toward the pressure chambers 30, thereby reducing the volume of the pressure chambers 30 and applying pressure to the ink in the pressure chambers 30. The ink passes through the connection flow paths 36 and is ejected from the nozzles 31. At the same time, ink in the common flow channel 29 is supplied to the pressure chamber 30 through the communication flow channel 35 , and ink is also supplied from the ink tank 9 to the common flow channel 29 .

[0020] The plurality of actuators 22x formed on the actuator member 22 function as unimorph actuators, and can be independently deformed in response to the application of voltages to the individual electrodes 51 by the driver IC 5D.

[0021] 2, the sealing member 23 is disposed in the center of the surface 21a of the flow path member 21, similar to the actuator member 22, and does not cover the supply ports 27 and the return ports 28, but covers all of the pressure chambers 30 that open to the surface 21a. The sealing member 23 has a rectangular shape that is slightly smaller than the flow path member 21 and slightly larger than the actuator member 22 when viewed in the vertical direction. The sealing member 23 is adhered to the surface 21a via an adhesive, and seals the pressure chambers 30. The sealing member 23 is made of a material different from the piezoelectric layers 61 and 62 (a material with low ink permeability, such as stainless steel), and does not have a portion that functions as an actuator.

[0022] In this embodiment, the thickness of each of the piezoelectric layers 61, 62 is 10 μm or more, the thickness of the sealing member 23 is about 10 μm, and the thickness of each of the electrodes 51, 52 is about 0.5 to 1.5 μm.

[0023] As shown in Fig. 4, the control unit 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, and a RAM (Random Access Memory) 103. The ROM 102 stores programs and data for the CPU 101 to perform various controls. The RAM 103 temporarily stores data used by the CPU 101 when executing the programs. The CPU 101 performs various controls in accordance with the programs and data stored in the ROM 102 and RAM 103, based on data input from an external device (such as a personal computer) or an input unit (switches and buttons provided on the outer surface of the housing of the printer 1).

[0024] FIG. 5 shows an example of a drive signal supplied to the individual electrodes 51 by the driver IC 5D under the control of the control unit 100. The drive signal X shown in FIG. 5 includes three rectangular pulses within one ejection cycle (the time from time t0 to time t1) for forming one dot. The three pulses are composed of a main pulse Pm, a pre-pulse Pp applied before the main pulse Pm, and a cancel pulse Pc applied after the main pulse Pm. The main pulse Pm is used to eject droplets of a predetermined size from the nozzle 31 within one ejection cycle. From the perspective of increasing the ejection pressure, the pulse width Tm of the main pulse Pm is preferably close to AL (Acoustic Length: the round-trip propagation time of a pressure wave within the individual flow path 32). The pre-pulse Pp and cancel pulse Pc are used to suppress satellites and mist, and have pulse widths Tp and Tc smaller than the pulse width Tm of the main pulse Pm.

[0025] In this embodiment, in the initial state (time t0), a predetermined drive potential (VDD) is applied to the individual electrode 51, and the portion of the piezoelectric layer 61 sandwiched between the individual electrode 51 and the common electrode 52 (the actuator 22x) contracts in the planar direction, and the portion of the actuator member 22 and the sealing member 23 that vertically overlaps with the pressure chamber 30 is deformed convexly toward the pressure chamber 30. Then, when the main pulse Pm rises and the individual electrode 51 reaches ground potential (0 V), the contraction of the actuator 22x in the planar direction is released, and the above portion becomes flat. This increases the volume of the pressure chamber 30 compared to the initial state, and ink is sucked from the common flow path 29 into the individual flow path 32. Further thereafter, when the main pulse Pm falls and the drive potential (VDD) is applied to the individual electrode 51, the actuator 22x contracts again in the planar direction, and the above portion is deformed convexly toward the pressure chamber 30. At this time, the decrease in the volume of the pressure chamber 30 increases the ink pressure, and ink is ejected from the nozzle 31.

[0026] That is, in this embodiment, the actuator 22x is driven by a "pull-fire method" in which the volume of the pressure chamber 30 is increased from a predetermined volume and then decreased to below the predetermined volume, thereby ejecting ink from the nozzle 31. In the "pull-fire method," a negative pressure wave is generated within the pressure chamber 30 when the volume of the pressure chamber 30 increases, and then the negative pressure wave reverses and returns to the pressure chamber 30 as a positive pressure wave, thereby decreasing the volume of the pressure chamber 30, thereby generating a positive pressure wave within the pressure chamber 30, and these pressure waves are superimposed. This superposition of pressure waves applies a large pressure to the ink within the pressure chamber 30, thereby increasing the ejection pressure.

[0027] Furthermore, in recent years, from the viewpoint of high-speed recording, there has been a demand for driving the actuator 22x at a high frequency. However, in the case of a drive signal X including a rectangular main pulse Pm and a rectangular cancel pulse Pc within one ejection cycle as shown in Fig. 5, if the frequency becomes 50 kHz or higher, ejection may become unstable.

[0028] As a result of extensive research, the inventors of the present application have discovered that the sum of Tw (the time from the falling edge of the main pulse Pm to the rising edge of the cancel pulse Pc) and Tc (the pulse width of the cancel pulse Pc) is correlated with the limit frequency Fl (the limit frequency at which successively ejected ink droplets do not join together, and a dot is formed independently for each ink droplet).

[0029] The "rising edge" of a pulse refers to the change in potential from the initial potential to a predetermined potential of the pulse. The "falling edge" of a pulse refers to the change in potential from the predetermined potential of the pulse to the initial potential. In this embodiment, since the "pull-and-shoot method" is adopted, the potential drops when the pulse rises and rises when the pulse falls, as shown in FIG. 5.

[0030] Specifically, Fig. 6 shows the relationship between Tw+Tc for the cancel pulse Pc and the limit frequency Fl. Fig. 7 shows the relationship between the total time Tt (=Tp+Tv+Tm+Tw+Tc) for the three pulses Pp, Pm, and Pc and the limit frequency Fl. Figs. 6 and 7 plot the values ​​of the limit frequencies Fl when the actuator 22x is driven using a plurality of drive signals X that are different from each other in at least one of Tp (pulse width of the pre-pulse Pp), Tv (time from the falling edge of the pre-pulse Pp to the rising edge of the main pulse Pm), Tm (pulse width of the main pulse Pm), Tw (time from the falling edge of the main pulse Pm to the rising edge of the cancel pulse Pc), and Tc (pulse width of the cancel pulse Pc). 6 and 7, the equation obtained by regression analysis of the limit frequency Fl is shown by a dashed line. It can be seen that the equation "-11.3 x (Tw + Tc) + 120" shown in FIG. 6 is closer to the actual limit frequency Fl than the equation "-10.4 x Tt x 190" shown in FIG. 7.

[0031] Therefore, in this embodiment, when the drive frequency of the drive signal X is f (unit: kHz), the time from the falling edge of the main pulse Pm to the rising edge of the cancel pulse Pc is Tw (unit: μsec), and the pulse width of the cancel pulse Pc is Tc (unit: μsec), the following formula (1) is established (in other words, when driving at an arbitrary frequency f of 50 kHz or higher, Tw+Tc is set so that the following formula (1) is established). This makes it possible to achieve stable ejection with high frequency driving. 50≦f≦-11.3×(Tw+Tc)+120 (1)

[0032] The inventors of the present application further focused on the displacement of the meniscus formed in the nozzle 31 and discovered that the product of the maximum displacement Q (see Figure 8) of the meniscus that occurs after the application of the cancel pulse Pc and the time Tq from the start time t2 (see Figure 5) of the application of the drive signal X within one ejection cycle to the time tq at which the maximum displacement Q occurs is correlated with the limit frequency Fl.

[0033] Specifically, Fig. 8 shows the displacement of the meniscus with application of the drive signal X. In Fig. 8, R is the maximum displacement of the meniscus that occurs after application of the main pulse Pm, and tr is the time point at which the maximum displacement R occurs. Fig. 9 shows the relationship between the product of Q and Tq and the limit frequency Fl. As in Figs. 6 and 7, Fig. 9 plots the values ​​of the limit frequency Fl when the actuator 22x is driven using a plurality of drive signals X in which at least one of Tp, Tv, Tm, Tw, and Tc (see Fig. 5) is different from one another. Fig. 9 also shows the formula "-4 x 10" obtained by regression analysis of the limit frequency Fl. 14 ×(Q×Tq)+106” is shown by a dashed line, and it can be seen that this formula is close to the actual limit frequency Fl.

[0034] Therefore, in this embodiment, the maximum displacement of the meniscus that occurs after the application of the cancel pulse Pc is defined as Q (unit: m 3), and when the time from the start time t2 (see FIG. 5) of application of the drive signal X within one ejection cycle to the time tq at which the maximum displacement Q occurs is Tq (unit: μsec), the following formula (2) is established (in other words, when driving at an arbitrary frequency f of 50 kHz or higher, Q and Tq are set so that the following formula (2) is established). This makes it possible to more reliably achieve stable ejection with high-frequency driving. f≦-4×10 14 ×(Q×Tq)+106 (2)

[0035] In this embodiment, the resolution of the image formed by the ink ejected from the nozzles 31 is 1200 dpi or higher. High-frequency driving is effective in achieving a high resolution of 1200 dpi or higher, and stable ejection can be achieved by high-frequency driving by satisfying the following formulas (1) and (2).

[0036] The multiple nozzles 31 are aligned at a density of 50 dpi or more in the transport direction (the direction of relative movement between the paper P, which is the recording medium, and the multiple nozzles 31). In this case, by providing multiple rows of nozzles 31 aligned at this density, a high resolution of 1200 dpi or more can be effectively achieved.

[0037] Furthermore, in this embodiment, when the pulse width of the main pulse Pm is Tm (unit: μsec) and the round-trip propagation time of the pressure wave in the individual flow path 32 is AL (unit: μsec), the following formula (3) is established (in other words, Tm is set so that the following formula (3) is established). This makes it possible to increase the discharge pressure. AL×0.7≦Tm≦AL×1.3 (3)

[0038] AL is 6 μsec or less. If AL exceeds 6 μsec, the pulse width Tm of the main pulse Pm becomes long (and thus the length of one ejection cycle becomes long), making it difficult to achieve high-frequency driving. In this embodiment, because AL is 6 μsec or less, the pulse width Tm of the main pulse Pm becomes short (and thus the length of one ejection cycle becomes short), making it easy to achieve high-frequency driving.

[0039] Tw is 1 μsec or more, and Tc is 1 μsec or more (see FIG. 5). The rise and fall of the pulse takes about 1 μsec, and there is a slight difference in the rise and fall times for each actuator 22x. If Tw and Tc are less than 1 μsec, there may be an actuator 22x among the multiple actuators 22x whose pulse does not rise or fall completely. Therefore, the difference in rise and fall times for each actuator 22x has a significant effect on the ejection performance, and this may cause variations in the ejection performance between the nozzles 31. In this embodiment, this problem can be suppressed by setting Tw and Tc to 1 μsec or more.

[0040] The member that constitutes the nozzle 31 (plate 49 shown in FIG. 3) is made of metal. Metal has better abrasion resistance than resins such as polyimide. Therefore, even with long-term use, the nozzle 31 wears less, and stable ejection can be achieved with high-frequency driving.

[0041] A sealing member 23 made of a material different from that of the piezoelectric layers 61, 62 is disposed between the flow path member 21 and the actuator member 22. In this case, even if cracks occur in the piezoelectric layers 61, 62, the ink in the flow path member 21 does not penetrate into the cracks in the piezoelectric layers 61, 62, and defects (such as short circuits between the electrodes 51, 52) caused by ink penetrating into the cracks can be avoided.

[0042] <Modification> Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design modifications are possible within the scope of the claims.

[0043] In the above embodiment, the drive signal X (see FIG. 5) includes a pre-pulse Pp in addition to the main pulse Pm and the cancel pulse Pc within one ejection cycle (the time from time t0 to time t1), but the pre-pulse Pp may be omitted.

[0044] In the above-described embodiment, the electrodes constituting the actuator have a two-layer structure including an individual electrode and a common electrode, but may also have a three-layer structure (for example, a structure including a drive electrode to which a high potential and a low potential are selectively applied, a high-potential electrode that is held at a high potential, and a low-potential electrode that is held at a low potential).

[0045] The head is not limited to a serial type, but may be a line type.

[0046] The ejection target is not limited to paper, but may be, for example, cloth, a substrate, a plastic member, or the like.

[0047] The liquid ejected from the nozzles is not limited to ink, but may be any liquid (for example, a treatment liquid that aggregates or precipitates components in the ink, etc.).

[0048] The present invention is not limited to printers, but can also be applied to facsimiles, copiers, multifunction machines, etc. The present invention can also be applied to liquid ejection devices used for purposes other than image recording (for example, liquid ejection devices that eject conductive liquid onto a substrate to form a conductive pattern). [Explanation of symbols]

[0049] 1. Printer (liquid ejection device) 21 Flow path member 21a surface 22 Actuator member 22x Actuators 23 Sealing member 30 Pressure Chamber 31 nozzles 32 individual channels 51 Individual electrodes 61,62 Piezoelectric layer 100 control section X drive signal Pm main pulse Pc Cancel Pulse

Claims

1. A nozzle; a pressure chamber communicating with the nozzle; an actuator that applies pressure to the liquid in the pressure chamber; a control unit that applies a drive signal to the actuator, the drive signal includes, within one ejection cycle for forming one dot, a rectangular main pulse and a rectangular cancel pulse that is applied after the main pulse and has a pulse width smaller than that of the main pulse, and the drive signal is a push-pull type that ejects liquid from the nozzle by increasing the volume of the pressure chamber from a predetermined volume and then decreasing it to equal to or less than the predetermined volume, A liquid ejection device characterized in that the following formula (1) holds when the drive frequency of the drive signal is f (unit: kHz), the time from the falling edge of the main pulse to the rising edge of the cancel pulse is Tw (unit: μsec), and the pulse width of the cancel pulse is Tc (unit: μsec). 50≦f≦-11.3×(Tw+Tc)+120...(1)

2. The maximum displacement of the meniscus of the nozzle that occurs after the application of the cancel pulse is Q (unit: m 3 2. The liquid ejection device according to claim 1, wherein the following formula (2) holds when the time from the start of application of the drive signal within one ejection cycle to the time when the maximum displacement Q occurs is Tq (unit: μsec). f≦-4×10 14 ×(Q×Tq)+106 ・・・(2)

3. 3. The liquid ejection device according to claim 1, wherein the resolution of the image formed by the liquid ejected from the nozzles is 1200 dpi or higher.

4. 4. The liquid ejection device according to claim 3, wherein the plurality of nozzles are aligned in a direction of relative movement between the recording medium and the plurality of nozzles at a density of 50 dpi or more.

5. A liquid ejection device according to any one of claims 1 to 4, characterized in that when the pulse width of the main pulse is Tm (unit: μsec) and the round-trip propagation time of the pressure wave in the individual flow path including the pressure chamber and the nozzle is AL (Acoustic Length) (unit: μsec), the following formula (3) is established: AL × 0.7 ≦ Tm ≦ AL × 1.3 (3)

6. 6. The liquid ejection device according to claim 5, wherein the AL is 6 [mu]sec or less.

7. 7. The liquid ejection device according to claim 1, wherein Tw is 1 μsec or more and Tc is 1 μsec or more.

8. 8. The liquid ejection device according to claim 1, wherein a member constituting the nozzle is made of metal.

9. a flow path member in which the nozzle and the pressure chamber are formed, the flow path member having a surface to which the pressure chamber is open; a sealing member disposed on the surface and sealing the pressure chamber; an actuator member that configures the actuator, the actuator member having a piezoelectric layer disposed on a surface of the sealing member opposite to the flow path member and individual electrodes formed on a surface of the piezoelectric layer opposite to the sealing member, 9. The liquid ejection device according to claim 1, wherein the sealing member is made of a material different from that of the piezoelectric layer.

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