KR20090081759A - Fluid ejecting device - Google Patents

Abstract

A fluid ejecting device is provided to increase the discharging rate of working fluid in a nozzle by amplifying reflected acoustic wave when acoustic wave generated by the drive of a piezoelectric element is reflected to a chamber. A fluid ejecting device comprises a reservoir(20), a chamber(30), a piezoelectric element(40), and a nozzle(50). The reservoir stores the working fluid. One end of the chamber is connected to the reservoir and the chamber forms the flow path for the movement of the working fluid. The piezoelectric element is driven with voltage signals which are installed at one side of the chamber. The nozzle is connected to the other end of the chamber and discharges the working fluid with the drive of the piezoelectric element. In the chamber, a flow path being adjacent to the reservoir is formed in a tapered form toward the reservoir and the acoustic wave generated by the drive of the piezoelectric element is amplified and is reflected from the reservoir to the chamber.

Description

Fluid Discharge Device {FLUID EJECTING DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid discharge device applied to an inkjet printhead, and more particularly, to an acoustic wave generated inside a chamber according to the operation of a piezoelectric element. By analyzing the behavior and using the same, the present invention relates to a fluid discharge device capable of increasing the discharge amount of the working fluid or stably discharging the working fluid.

In general, an inkjet printhead is a device that prints a predetermined color image by discharging minute droplets of printing ink. The inkjet printhead is classified into a thermal type and a piezoelectric type according to an ink ejection mechanism. do.

The thermally driven inkjet printhead is a method of generating bubbles in ink, which is a working fluid, by using a heat source, and discharging ink by the expansion force of the bubbles. On the other hand, the piezoelectric inkjet printhead is a method in which pressure is applied to ink as a piezoelectric element is deformed by applying a predetermined voltage signal, thereby discharging ink. Piezoelectric inkjet printheads do not heat the ink, there is an advantage that the type of ink that can be used is not limited.

1 is a view showing a general configuration of an inkjet printhead according to the prior art. Referring to FIG. 1, in a conventional inkjet printhead according to the related art, a reservoir 3, a chamber 5, and a nozzle 7, which form a flow path of ink as a working fluid, form a flow path. It is formed inside the member 1. One side of the chamber 5 is provided with a piezoelectric element 8 that deforms in accordance with a predetermined voltage signal, and a membrane 9 serving as a diaphragm of the piezoelectric element 8.

The printer is provided with a plurality of inkjet printheads having the same configuration as described above for printing. The reservoir 3 stores ink, and communicates with the chamber 5 of each inkjet printhead to supply ink. Therefore, when the piezoelectric element 8 is driven and deformed, pressure is applied to the chamber 5, and ink in the chamber 5 is discharged through the nozzle 7. When the deformation of the piezoelectric element 8 is restored, the internal pressure of the chamber 5 becomes relatively small so that ink moves from the reservoir 3 to be filled in the chamber 5. As a result, the inkjet printhead has a driving frequency of several kHz or more as the above process is repeated.

On the other hand, the design of the inkjet printhead according to the prior art mainly focuses on the hydrodynamic behavior of the ink flow in order to improve the ink ejection performance. The conventional design method of the inkjet printhead will be described.

As shown in FIG. 1, when the internal pressure of the chamber 5 increases as the piezoelectric element 8 is driven, the pressure energy is divided and transmitted in the direction of the nozzle 7 and the chamber inlet 6. This shows that all of the pressure energy generated in the chamber 5 is not used for ink ejection, and energy is wasted. Therefore, the design of the inkjet printhead according to the prior art is mainly designed to increase the fluid resistance at the chamber inlet 6 in order to increase the ink ejection amount at the nozzle 7.

That is, as shown in Fig. 2, it is designed to have a restrictor 6 "which increases the fluid resistance by reducing the cross-sectional area of the flow path at the inlet side of the chamber or bending the flow path. The ink flow inside the inkjet printhead results from the incompressible flow, ie the density of the ink does not change with pressure.

However, the piezoelectric element 8 generates an acoustic wave because a small deformation is repeatedly generated in a very short time, and thus the ink flow in the inkjet printhead can be understood from the viewpoint of generating the acoustic wave. That is, the acoustic wave generated by the piezoelectric element 8 is required to a certain time to be transmitted to the nozzle (7). Therefore, it is necessary to give importance to the characteristic that acoustic waves propagate in ink as a medium. Because of this, it can be said that the working fluid ink has a compressibility.

In addition, the wavelength λ of the generated acoustic wave can be obtained by multiplying the sound speed C of the ink by the driving frequency of the piezoelectric element, and the wavelength λ of the obtained acoustic wave is the total length of the inkjet printhead. If smaller, the compressibility and propagation of acoustic waves should be considered. In other words, it may be reasonable to approach the ink flow inside the inkjet printhead from the perspective of acoustic wave transfer.

However, in the prior art, since the ink flow inside the inkjet printhead is regarded as the movement of an incompressible fluid, that is, designed to pay attention to hydrodynamic behavior, there is a physical limitation in improving the performance of the inkjet head.

Therefore, in order to solve this problem, it is necessary to accurately grasp the acoustic wave behavior inside the inkjet printhead and reflect it in the design.

The present invention has been made to solve the above-mentioned problems of the prior art, and accurately analyzes the behavior of acoustic waves generated in a fluid ejection apparatus such as an inkjet printhead, and uses the fluid ejection apparatus with improved fluid ejection performance. The purpose is to provide.

In order to achieve the above object, the fluid discharge device according to the first embodiment of the present invention comprises a reservoir for storing the working fluid, a chamber in which one end is in communication with the reservoir to form a flow path for the movement of the working fluid, A piezoelectric element driven by a voltage signal installed and applied to one side of the chamber, and a nozzle communicating with the other end of the chamber to discharge the working fluid by driving the piezoelectric element, wherein the chamber includes the reservoir and the reservoir. Adjacent flow paths are formed to become narrower toward the reservoir side, so that acoustic waves generated by driving the piezoelectric element are amplified and reflected from the reservoir to the chamber. At this time, the piezoelectric element is preferably acting to increase the volume of the chamber during the initial drive.

A fluid discharge device according to a second embodiment of the present invention includes a reservoir for storing a working fluid, a chamber having one end communicating with the reservoir to form a flow path for movement of the working fluid, and installed at one side of the chamber. A piezoelectric element driven by a voltage signal, which is in communication with the other end of the chamber, is driven to drive the piezoelectric element on a nozzle in which the working fluid is discharged by driving the piezoelectric element and a flow path of the chamber adjacent to the reservoir. And an acoustic wave canceling interference member for canceling and interfering acoustic waves generated by and reflected from the reservoir. At this time, the piezoelectric element is preferably acting to reduce the volume of the chamber during the initial drive.

In addition, in the fluid discharge device according to the second embodiment of the present invention, the acoustic wave canceling interference member is a plurality of first blocks arranged in a predetermined interval perpendicular to the longitudinal direction of the chamber, and the first blocks And a plurality of second blocks arranged at a predetermined interval perpendicular to the longitudinal direction of the chamber in a staggered state with each other, wherein a distance between the first block and the second block is 1/4 of the acoustic wave wavelength. Do.

On the other hand, the acoustic wave canceling interference member may include a plurality of third blocks arranged at regular intervals perpendicular to the longitudinal direction of the chamber, and at the center of the reflecting surface of each of the third blocks on which the acoustic waves are reflected. It is composed of a fourth block extending in the longitudinal direction, the length of the fourth block is preferably 1/4 of the wavelength of the acoustic wave.

In the fluid ejection apparatus according to the first embodiment of the present invention, in the expansion mode driving method of the piezoelectric element, the flow path is gradually narrowed toward the reservoir side so that acoustic waves generated by the piezoelectric element are driven to the reservoir side. When reflected from the chamber to, there is an advantage that can increase the discharge amount of the working fluid from the nozzle by amplifying the reflected acoustic wave.

In addition, the fluid ejection apparatus according to the second embodiment of the present invention includes the acoustic wave canceling interference member on the channel of the chamber adjacent to the reservoir in the compression mode driving method of the piezoelectric element, and thus the intensity of the acoustic wave reflected from the reservoir to the chamber. There is an advantage that can be minimized to improve the ink ejection performance in the nozzle.

The object of the present invention and the configuration, operation and effect of the present invention to achieve the same will be more clearly understood by the following detailed description of the preferred embodiment of the present invention with reference to the accompanying drawings.

Prior to the detailed description, since the fluid ejection apparatus according to the present invention is suitable for use in the printhead of an inkjet printer, the following description will be given on the assumption that it is applied to the inkjet printhead. However, the present invention is not limited to being applied to an inkjet printhead, but it is found that it can be applied to a fluid discharge device other than the inkjet printhead.

[First Embodiment]

3A is a view showing the configuration of a fluid ejection apparatus applied to the inkjet printhead according to the first embodiment of the present invention and the propagation mechanism of the acoustic waves, and FIG. 3B is a view showing the shape of the AB section in the chamber of FIG. 3A. 4 is a diagram showing a driving waveform of the piezoelectric element in the first embodiment of the present invention.

The fluid ejection apparatus applied to the inkjet printhead according to the first embodiment of the present invention includes a reservoir 20, a chamber 30, a piezoelectric element 40, and a nozzle 50 as shown in FIG. 3A. It is composed. The reservoir 20, the chamber 30, and the nozzle 50 forming the flow path of the ink, that is, the working fluid, are formed by the flow path forming member 10. The flow path forming member 10 is manufactured by cutting a plurality of thin plates mainly made of a ceramic material, a metal material, or a synthetic resin material to form a flow path, and then stacking the plurality of thin plates.

The reservoir 20 stores ink, which is a working fluid, and supplies ink to the chambers 30 of each inkjet printhead. One end of the chamber 30 communicates with the reservoir 20 to form a straight flow path of ink, and the other end of the chamber 30 is provided with a nozzle 50 for discharging ink.

The piezoelectric element 40 is installed in the flow path forming member 10 to be located at one side of the chamber 30. In addition, a membrane 45 serving as a diaphragm of the piezoelectric element 40 is provided in the flow path forming member 10. The piezoelectric element 40 has a form in which a piezoelectric thin plate and an electrode for applying a voltage to the piezoelectric thin plate are stacked. In addition, the piezoelectric element 40 of each fluid discharge device has a voltage signal applying unit (not shown) connected to a control unit (not shown) is located outside thereof. That is, the voltage signal applying unit (not shown) applies a voltage signal to drive the piezoelectric element 40.

On the other hand, the initial driving of the piezoelectric element 40 varies depending on the type of voltage signal applied to the piezoelectric element 40 by the voltage signal applying unit (not shown). Hereinafter, a description will be given of the expansion mode driving method and the compression mode driving method according to the initial driving method of the piezoelectric element 40. In the expansion mode driving method, when a voltage signal is applied to the piezoelectric element 40, the piezoelectric element 40 is reduced to expand the volume of the chamber 30. In the compression mode driving method, a voltage signal having the same magnitude as that of the voltage signal in the expansion mode driving method and having the opposite polarity is applied. When the contact signal is applied, the piezoelectric element 40 is enlarged to The volume will be compressed.

The fluid ejection apparatus according to the first embodiment of the present invention is an embodiment in which the initial driving of the piezoelectric element 40 is in the expansion mode. 3A and 3B, the AB section of the chamber 30, that is, the flow path adjacent to the reservoir 20 is gradually narrowed toward the reservoir 20 side as shown in FIGS. 3A and 3B. It features.

Hereinafter, the operation of the fluid discharge device according to the first embodiment of the present invention having the configuration as described above with reference to FIGS. 3A to 4 will be described.

On the other hand, the drawing drawn on the lower end of the fluid discharge device in Figure 3a is a view for explaining the propagation mechanism of the acoustic wave generated by the piezoelectric element 40, the behavior of the acoustic wave according to the drive time of the piezoelectric element 40 It is shown. 4 shows a drive waveform of the piezoelectric element 40.

In the piezoelectric element 40, when the voltage signal is applied, the piezoelectric element 40 is reduced and the membrane 45 descends downward to expand the volume of the chamber 30, and acoustic waves are generated (t ₁ ). . At this time, negative acoustic waves are generated as shown in Figs. 3A and 4 (the acoustic waves generated when the volume of the chamber is expanded are arbitrarily negative). Then, the generated acoustic wave is divided into the nozzle 50 side direction and the reservoir 20 side direction of the chamber 30 to proceed (t ₂ ). At this time, the reflection of the acoustic wave is generated where the change of the acoustic impedance occurs (t ₃ ). As the acoustic wave proceeds to the reservoir 20 side, the acoustic wave resistance changes as the cross-sectional area of the flow path suddenly increases at the chamber entrance A, and the acoustic wave is reflected. At this time, since the chamber inlet A acts as an acoustically fixed end, the phase of the acoustic wave is changed from negative (−) to positive (+) and reflected (t ₃ ). On the contrary, since the acoustic wave traveling toward the nozzle 50 is almost blocked, the acoustic wave acts as a free end, so that the acoustic wave is reflected while the phase of the acoustic wave is not changed (t ₃ ).

Thereafter, when the voltage signal applied to the piezoelectric element 40 is initialized and changed to 0 V, the piezoelectric element 40 and the membrane 45 are restored to their original state (t ₄ ). At this time, since the volume of the chamber 30 is relatively compressed, positive acoustic waves are generated. In this case, if the flow path length of the chamber 30 and the intensity of the voltage applied to the piezoelectric element 40 are properly adjusted, a newly generated positive acoustic wave is changed in phase at the chamber inlet A and reflected. It causes positive acoustic waves and constructive interference (t ₄ ). Therefore, the discharge amount of the ink in the nozzle 50 can be increased by the positive interference wave (+5) (t ₅ ).

In the fluid discharge device according to the first embodiment of the present invention, as shown in FIG. 3B, an AB section of the chamber 30 toward the reservoir 20 is formed such that its flow path is gradually narrowed. Therefore, the acoustic wave reflected from the reservoir 20 toward the chamber 30 is amplified. As a result, the reinforcing interference effect described above can be maximized, and the ejection amount of the ink is greatly increased. At this time, since the inlet A of the chamber 30 is a passage through which ink, which is a working fluid, is refilled, the cross-sectional size of the inlet A of the chamber 30 should be appropriately designed in consideration of the refilling of the ink and the amplification of the acoustic wave described above. .

On the other hand, the fluid ejection apparatus applied to the inkjet printhead generates interference between acoustic waves generated as the driving frequency increases, which adversely affects the efficient meniscus retraction of the nozzle 50. This lowers the ink ejection performance of the nozzle 50. However, the inkjet printhead according to the first embodiment of the present invention overcomes this problem by constructively interfering acoustic waves and improves ink ejection performance by allowing ink droplets to be separated smoothly.

Second Embodiment

FIG. 5 is a diagram showing the configuration of a fluid discharge device applied to an inkjet printhead and a propagation mechanism of acoustic waves according to a second embodiment of the present invention, and FIG. 7A is a diagram illustrating an example of the acoustic wave canceling interference member of FIG. 5, and FIG. 7B is a diagram for explaining the principle of canceling interference of acoustic waves in FIG. 7A, and FIG. 8A is the sound of FIG. 5. FIG. 8B is a view illustrating another example of the wave canceling interference member, and FIG. 8B is a view for explaining the principle of canceling interference of acoustic waves in FIG. 8A.

As shown in FIG. 5, the fluid ejection apparatus applied to the inkjet printhead according to the second embodiment of the present invention has a reservoir 20, a chamber 30, a piezoelectric element 40, a nozzle 50, and an acoustic wave. It comprises a destructive interference member (60, 70). The reservoir 20, the chamber 30, and the nozzle 50 are formed by the flow path forming member 10, and the piezoelectric element 40 and the membrane 45 are provided on one side of the chamber 30 in the first embodiment. Same as the example.

The piezoelectric element 40 of the fluid discharge device according to the second embodiment of the present invention is characterized in that it acts to reduce the volume of the chamber 30 during the initial driving. That is, in the piezoelectric element 40 of the present embodiment, a voltage signal having the same magnitude and opposite polarity as that of the expansion mode driving method and the voltage signal of the first embodiment is applied to the piezoelectric element 40 so that the volume of the chamber 30 is increased. It has a compression mode driving method to be compressed.

As shown in FIG. 5, the fluid ejection apparatus applied to the inkjet printhead according to the second embodiment of the present invention has a sound on the flow path of the chamber 30 adjacent to the reservoir 20, that is, the AB section of the chamber 30. Characterized in that the wave cancellation interference member (60, 70) is provided.

Referring to FIGS. 7A and 7B illustrating an example of the acoustic wave canceling interference member of FIG. 5, the acoustic wave canceling interference member 60 is arranged in a predetermined interval perpendicular to the longitudinal direction of the chamber 30. Block 62 and a plurality of second blocks (64) arranged at regular intervals in a state perpendicular to the longitudinal direction of the chamber 30 in a state staggered with the first blocks (62). At this time, the distance between the first block 62 and the second block 64 is characterized in that 1/4 of the acoustic wave wavelength.

Meanwhile, referring to FIGS. 8A and 8B, which illustrate another example of the acoustic wave canceling interference member of FIG. 5, the acoustic wave canceling interference member 70 may be arranged at regular intervals to be perpendicular to the longitudinal direction of the chamber 30. Three blocks 72 and a fourth block 74 extending in the longitudinal direction of the chamber 30 at the central portion of the reflection surface 72a of each of the third blocks on which acoustic waves are reflected. At this time, the length of the fourth block 74 corresponding to the distance between the third block 72 and the fourth block 74 is 1/4 of the acoustic wave wavelength.

5 to 8 will be described the operation of the fluid discharge device applied to the inkjet printhead according to the second embodiment of the present invention having the configuration as described above.

5 is a view for explaining the propagation mechanism of the acoustic wave generated by the piezoelectric element 40, the behavior of the acoustic wave according to the driving time of the piezoelectric element 40. It is shown. 6 shows a drive waveform of the piezoelectric element 40.

When the piezoelectric element 40 is applied with a voltage signal, the piezoelectric element 40 is enlarged and the membrane 45 rises upward to compress the volume of the chamber 30 and generate acoustic waves (t ₁ ). In this case, as illustrated in FIGS. 5 and 6, a positive sound wave is generated as opposed to the expansion mode driving method. Then, the generated acoustic wave is divided into the nozzle 50 side direction and the reservoir 20 side direction of the chamber 30 to proceed (t ₂ ).

 At this time, the reflection of the acoustic wave is generated where the change of the acoustic impedance occurs (t3). As the acoustic wave proceeds to the reservoir 20 side, the acoustic wave resistance changes as the cross-sectional area of the flow path suddenly increases at the inlet A of the chamber 30 so that the acoustic wave is reflected. At this time, since the chamber inlet A acts as an acoustically fixed end, the phase of the acoustic wave is changed from positive (+) to negative (-) and reflected (t3). On the contrary, the acoustic wave traveling toward the nozzle 50 is almost blocked, so that the acoustic wave acts as a free end and the reflection is performed without changing the phase of the acoustic wave (t3).

At this time, in the second embodiment of the present invention, unlike the expansion mode driving method of the first embodiment, the acoustic wave propagated to the reservoir 20 side is the acoustic wave canceling interference members 60 and 70 installed in the AB section of the chamber 30. It is canceled and attenuated while colliding with and minimizes the acoustic wave reflected from the reservoir 20 to the chamber 30 (t ₄ , t ₅ ).

The reason for installing the acoustic wave canceling interference members 60 and 70 in the second embodiment of the present invention will be described. Even though the voltage signal is initialized after the piezoelectric element 40 is driven by the applied voltage signal, the residual vibration of the piezoelectric element 40 is combined with the inertial force of the ink to continuously generate and propagate acoustic waves in the chamber 30. This leads to vibration of the meniscus of the nozzle 50, and the continued vibration of the meniscus continues until the next voltage signal is applied, causing unstable ejection of the ink droplets. Therefore, it is necessary to improve the ink ejection performance by canceling the interference of the acoustic wave generated in the piezoelectric element 40.

On the other hand, an example of the acoustic wave canceling interference member 60 in the second embodiment of the present invention is shown in Figs. 7A and 7B. The principle of canceling interference of acoustic waves will be described with reference to FIG. 7B. The acoustic wave generated by the piezoelectric element 40 and directed toward the reservoir 20 side (arrow direction) is first reflected on the second reflecting surface 64a of each of the plurality of second blocks 64. In addition, the acoustic wave passing between the second blocks 64 is reflected again at the first reflective surface 62a of the first block 62 arranged in a state of being staggered with the second blocks 64. In this case, the distance between the first reflecting surface 62a of the first block 62 and the second reflecting surface 64a of the second block 64 is 1/4 of the acoustic wave wavelength λ. The reflected wave α in 64 and the reflected wave β in the first block 62 have opposite phases to each other, so that offset interference occurs.

Further, another example of the acoustic wave canceling interference member 70 in the second embodiment of the present invention is shown in Figs. 8A and 8B. The principle of canceling interference of acoustic waves will be described with reference to FIG. 8B. The acoustic wave generated by the piezoelectric element 40 and directed toward the reservoir 20 side (arrow direction) is first reflected on the fourth reflecting surface 74a of each of the plurality of fourth blocks 74. The acoustic wave passing between the fourth blocks 74 is reflected again at the third reflection surface 72a of the third block 72. At this time, since the distance between the third reflective surface 72a of the third block 72 and the fourth reflective surface 74a of the fourth block 74 is 1/4 of the acoustic wave wavelength λ, the fourth block ( The reflected wave θ at 74 and the reflected wave γ at the third block 72 have opposite phases to each other so that destructive interference occurs.

The fluid ejection apparatus applied to the inkjet printhead according to the second embodiment of the present invention realizes the vibration reduction of the meniscus by canceling the interference of the acoustic waves generated by the piezoelectric element 40 as described above. It is possible to improve the discharge performance. It also enables stable high frequency drive of the fluid ejection device applied to the inkjet printhead.

The preferred embodiments of the present invention described above and illustrated in the drawings should not be construed as limiting the technical idea of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can change and change the technical idea of the present invention in various forms. Therefore, such improvements and modifications will fall within the protection scope of the present invention as long as it will be apparent to those skilled in the art.

1 is a view showing a general configuration of an inkjet printhead according to the prior art,

2 is a view for explaining a design method of an inkjet printhead according to the prior art;

3A is a view showing the configuration of a fluid discharge device applied to an inkjet printhead and a propagation mechanism of acoustic waves according to the first embodiment of the present invention;

3B is a view showing the shape of the AB section in the chamber of FIG. 3A;

4 is a diagram showing a driving waveform of a piezoelectric element according to the first embodiment of the present invention;

5 is a view showing a configuration of a fluid ejection apparatus applied to an inkjet printhead according to a second embodiment of the present invention and a propagation mechanism of acoustic waves;

6 is a view showing a driving waveform of a piezoelectric element according to a second embodiment of the present invention;

7A is a diagram illustrating an example of the acoustic wave canceling interference member of FIG. 5;

FIG. 7B is a view for explaining the principle of canceling interference of acoustic waves in FIG. 7A; FIG.

8A is a view showing another example of the acoustic wave canceling interference member of FIG. 5;

FIG. 8B is a view for explaining the principle of canceling interference of acoustic waves in FIG. 8A

<Explanation of symbols for the main parts of the drawings>

10: flow path forming member 20: reservoir (reservoir)

30 chamber 40 piezoelectric element

45: membrane 50: nozzle

60, 70: acoustic wave canceling interference member 62: first block

62a: first reflective surface 64: second block

64a: second reflective surface 72: third block

72a: third reflective surface 74: fourth block

74a: fourth reflective surface

Claims (6)

A reservoir for storing the working fluid; A chamber in which one end is in communication with the reservoir to form a flow path for movement of the working fluid; A piezoelectric element driven by a voltage signal installed and applied to one side of the chamber; A nozzle communicating with the other end of the chamber to discharge the working fluid by driving the piezoelectric element, The chamber is a fluid discharge device, characterized in that the flow path adjacent to the reservoir is formed to narrow gradually toward the reservoir side so that acoustic waves generated by the drive of the piezoelectric element is amplified and reflected from the reservoir to the chamber. The method of claim 1, The piezoelectric element is a fluid discharge device, characterized in that acts to increase the volume of the chamber during the initial drive. A reservoir for storing the working fluid; A chamber having one end communicating with the reservoir to form a flow path for movement of the working fluid; A piezoelectric element driven by a voltage signal installed and applied to one side of the chamber; A nozzle communicating with the other end of the chamber to discharge the working fluid by driving the piezoelectric element; And And an acoustic wave canceling interference member for canceling interference of acoustic waves generated by driving the piezoelectric element on the flow path of the chamber adjacent to the reservoir and reflected from the reservoir. The method of claim 3, The piezoelectric element is a fluid discharge device, characterized in that acts to reduce the volume of the chamber during the initial drive. The method of claim 3, The acoustic wave canceling interference member comprises a plurality of first blocks arranged at a predetermined interval perpendicular to the longitudinal direction of the chamber, and at a predetermined interval perpendicular to the longitudinal direction of the chamber while being staggered from the first blocks. Composed of a plurality of second blocks arranged, And a distance between the first block and the second block is one quarter of the wavelength of the acoustic wave. The method of claim 3, The acoustic wave canceling interference member includes a plurality of third blocks arranged at regular intervals perpendicular to the longitudinal direction of the chamber, and in the longitudinal direction of the chamber at the center of the reflective surface of each of the third blocks on which the acoustic waves are reflected. Consisting of an extended fourth block, The length of the fourth block is a fluid discharge device, characterized in that 1/4 of the wavelength of the acoustic wave.

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