JP2011024706A - Method for driving fluid ejection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid ejection device for ejecting a strong pulse flow. <P>SOLUTION: In a method for driving the fluid ejection device 1, the fluid ejection device 1 is equipped with a piezoelectric element 30 and a diaphragm 40 both of which change the volume of a pressure chamber 80 as a volume altering means, the outlet flow channel 82 opened in the volume changing direction of the pressure chamber 80 and the fluid ejection opening part 96 allowed to communicate with the outlet flow channel 82 and constituted so as to change the volume of the pressure chamber 80 by the piezoelectric element 30 and the diaphragm 40 to eject a liquid in a pulse-like state from the fluid ejection opening part 96. In the case that the cycle of the volume change of the pressure chamber 80 is set to T, the distance from the fluid ejection opening part 96 to the surface on the side of the pressure chamber 80 of the diaphragm 40 is set to D and the sonic velocity in the water of the section of the distance D is set to Q, the piezoelectric element 30 is driven so that the cycle T, the distance D and the sonic velocity Q satisfy T=n×2D/Q (wherein n is a positive integer). As a result, a pressure wave becomes resonance relation with respect to the drive frequency of the piezoelectric element 30 and the strong pulse flow can be ejected. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a driving method of a fluid ejecting apparatus that ejects fluid in pulses by changing a volume of a pressure chamber by a volume changing unit.

  There is known a fluid ejecting apparatus that ejects fluid in pulses to cut or cut an object. For example, in the medical field, as a surgical instrument for incising or excising living tissue, the volume of the pressure chamber is changed by driving the volume changing means to convert the fluid into a pulsating flow, and the fluid is pulsed from the fluid ejection opening. A fluid ejecting apparatus that ejects at high speed has been proposed (see, for example, Patent Document 1).

  In this fluid ejecting apparatus, when the sound velocity of the fluid in the connection channel is Q, the distance between the fluid resistance element on the outlet channel side and the fluid ejection opening is L, and the volume change frequency of the pressure chamber is f, n · 2L The volume of the pressure chamber is changed so as to satisfy = Q / f (or 2L / n = Q / f, where n is a positive integer).

JP 2005-152127 A

  In such Patent Document 1, since there is no valve on the fluid ejection opening side of the pressure chamber, a pressure wave propagates to the inside of the pressure chamber when fluid is ejected. Therefore, even if only the distance L from the fluid resistance element on the outlet flow channel side to the fluid ejection opening is considered, the pressure wave actually propagates to the inside of the pressure chamber. Therefore, a difference actually occurs in the distance L, and the influence of this difference cannot be ignored when the resonance principle of the pressure wave is used.

  Further, in the configuration according to Patent Document 1, since the outlet channel is provided in a direction substantially perpendicular to the volume change direction of the pressure chamber, when the pressure wave reaches the pressure chamber, it is reflected in the pressure chamber. The pressure is not uniform, and it is difficult to change the volume of the pressure chamber so as to resonate the pressure wave.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A fluid ejection device driving method according to this application example includes a volume changing unit that changes the volume of a pressure chamber, an outlet channel that opens in the direction of volume change of the pressure chamber, and the outlet channel. A pulsating flow ejection device that ejects fluid in a pulsed manner from the fluid ejection opening by changing the volume of the pressure chamber by the volume changing means. When the period of volume change of the pressure chamber is T, the distance from the fluid ejection opening to the deformation surface of the pressure chamber is D, and the sound velocity in water in the section of the distance D is Q, the period T and the distance D The volume changing means is driven so that the sound velocity Q satisfies T = n · 2D / Q (n is a positive integer).

  According to this application example, since the outlet channel is opened in the volume change direction of the pressure chamber, the pressure wave reaches the deformation surface of the pressure chamber (that is, the pressure chamber side surface of the volume changing unit), The pressure chamber can be deformed so as to resonate with the pressure reflected by the deformation surface of the pressure chamber. Therefore, the fluid can be jetted more strongly and in a pulse shape due to the resonance effect of the pressure wave.

  Application Example 2 In the fluid ejection device driving method according to the application example, the period T is the volume changing means within a range of T ± t1, where t1 is a time during which the volume of the pressure chamber is decreased. It is desirable to drive.

  The time during which the volume of the pressure chamber is reduced is at least the pressure fluctuation range. Therefore, the reflected wave in the flow path (range represented by the distance D) from the pressure chamber to the fluid ejection opening also becomes the pressure fluctuation range. Therefore, in order for the pressure wave generated at the time t1 during which the volume of the pressure chamber is reduced and the reflected wave in the flow path in the range represented by the distance D to overlap (resonate), at least in the period T, the volume The drive waveform of the changing means is in a range that is twice the time t1 during which the volume of the pressure chamber is reduced, and a resonance effect can be obtained within the range of the cycle T ± t1.

  Application Example 3 In the driving method of the fluid ejection device according to the application example described above, when the time during which the volume of the pressure chamber is increased is t2, the volume changing unit is driven in a range where t1 ≦ t2. Is desirable.

  In this way, after the fluid is pushed in the direction of decreasing the volume of the pressure chamber by the volume changing means, the volume is suddenly increased in the direction of increasing the volume, and the section from the fluid ejection opening to the deformation surface of the pressure chamber In this case, liquid column separation (described in detail in the embodiment) is likely to occur. When the liquid column separation occurs, the pressure wave cannot be propagated, and the resonance timing of the pressure wave is shifted.

  In this application example, the time t2 during which the volume of the pressure chamber is increased is set longer than the time t1 during which the volume of the pressure chamber is decreased, thereby suppressing the occurrence of liquid column separation. This makes it possible to stably perform strong fluid ejection due to the resonance effect.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration explanatory view showing a fluid ejecting apparatus as a surgical instrument according to a first embodiment. Sectional drawing which shows the cut surface which cut | disconnected the pulsating flow generation part which concerns on Embodiment 1 along the injection direction of a liquid. FIG. 2 is an explanatory block diagram illustrating a schematic configuration of a drive control unit according to the first embodiment. FIG. 3 is a drive waveform diagram illustrating an example of a drive waveform of the piezoelectric element according to the first embodiment. The drive waveform figure which shows the waveform of the combination of the drive waveform of a triangular wave, and rest time T = 1 / f. Sectional drawing which shows typically the state of the liquid in a connection flow path (an outlet flow path is included). FIG. 9 is a drive waveform diagram showing a relationship between a pressure reflected wave and a drive waveform timing according to the second embodiment. The drive waveform figure which shows the specific relationship between a pressure reflected wave and the timing of a drive waveform. The drive waveform figure showing the state which made the rising timing of the drive waveform the range of t1 with respect to the waveform of a pressure reflected wave. The block diagram which illustrates the case where a connection pipe is bent and formed (Example 1). The block diagram which illustrates the case where a connecting pipe is bent and formed (Example 2). The block diagram which illustrates the case where a connection pipe is bent and formed (Example 3).

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The fluid ejecting apparatus according to the present invention can be used in various ways such as drawing using ink, washing fine objects and structures, and a scalpel. However, in the embodiment described below, incision or excision of living tissue is performed. A fluid ejecting apparatus suitable for this will be described as an example. Therefore, the fluid used in the embodiment is a liquid such as water or physiological saline.
(Embodiment 1)

  FIG. 1 is a configuration explanatory view showing a fluid ejecting apparatus as a surgical instrument according to the first embodiment. In FIG. 1, a fluid ejecting apparatus 1 includes a liquid supply container 2 that contains a liquid, a pump 10 as a fluid supply unit, and a pulsating flow that converts the liquid supplied from the pump 10 into a pulsating flow and ejects it in a pulsed manner. Part 20. The pump 10 and the pulsating flow generator 20 are communicated with each other by the liquid supply tube 4.

  The pulsating flow generation section 20 is connected to a thin pipe-shaped connection flow path tube 90, and a nozzle 95 with a reduced flow path diameter is inserted into the distal end portion of the connection flow path pipe 90.

  Further, the fluid ejection device 1 is provided with a drive control unit 15 for controlling the driving of the pump 10 and the pulsating flow generation unit 20. In FIG. 1, the drive control unit 15 is disposed at a position separated from the pump 10 and the pulsating flow generation unit 20, but may be configured as a drive control unit including the pump 10.

  The pulsating flow generation unit 20 includes an injection command changeover switch 25 that starts and stops the pulsating flow generation unit 20. When the fluid ejecting apparatus 1 is used as a surgical instrument, the pulsating flow generation unit 20 is gripped and operated, so that the operability is improved by providing the ejection command changeover switch 25 at hand.

  First, the liquid flow action of the fluid ejecting apparatus 1 will be briefly described. The liquid stored in the container 2 is sucked by the pump 10 and supplied to the pulsating flow generation unit 20 through the liquid supply tube 4 at a constant pressure. The pulsating flow generation unit 20 includes a pressure chamber 80 and a piezoelectric element 30 and a diaphragm 40 (both see FIG. 2 for details) as volume changing means for changing the volume of the pressure chamber 80.

  The injection command changeover switch 25 is operated to activate the piezoelectric element 30, and the diaphragm 40 is deformed by expanding and contracting the piezoelectric element 30 in the direction of arrow A (see FIG. 2), and the volume of the pressure chamber 80 is changed. Generates pulsating flow. Then, the liquid is jetted at high speed in a pulsed manner through the connection flow channel tube 90 and the nozzle 95. The pulsating flow generation unit 20 will be described later with reference to FIG.

  Here, when an operation is performed using the fluid ejecting apparatus 1, the part grasped by the operator is the pulsating flow generation unit 20. Therefore, the liquid supply tube 4 is preferably as flexible as possible.

Next, the structure of the pulsating flow generation unit 20 according to this embodiment will be described.
FIG. 2 is a cross-sectional view showing a cut surface obtained by cutting the pulsating flow generation unit according to the present embodiment along the liquid ejecting direction. Note that FIG. 2 is a schematic diagram in which the vertical and horizontal scales of members or portions are different from actual ones for convenience of illustration. In FIG. 2, the pulsating flow generation unit 20 includes an inlet flow path 81 that supplies liquid from the pump 10 to the pressure chamber 80 via the liquid supply tube 4, and a piezoelectric element as a volume changing unit that changes the volume of the pressure chamber 80. 30 and the diaphragm 40, and an outlet channel 82 that sends liquid from the pressure chamber 80 to the fluid ejection opening 96.

  The outlet channel 82 is opened in the volume change direction of the pressure chamber 80 (that is, the direction substantially perpendicular to the surface of the diaphragm 40 on the pressure chamber 80 side).

  The diaphragm 40 is made of a disk-shaped thin metal plate, and the peripheral edge thereof is closely fixed by the lower case 50 and the upper case 70. Further, the pressure chamber 80 is a space formed by a concave portion formed on a surface of the upper case 70 facing the diaphragm 40 and the diaphragm 40.

  The piezoelectric element 30 is a laminated piezoelectric element in the present embodiment, and one of both ends is fixed to the diaphragm 40 and the other is fixed to the bottom plate 60.

  The upper case 70 and the lower case 50 are joined and integrated on opposite surfaces. A connection channel pipe 90 having a connection channel 91 that communicates with the outlet channel 82 is fitted into the upper case 70, and a nozzle 95 is inserted into the tip of the connection channel pipe 90. The nozzle 95 is provided with a fluid ejection opening 96 whose flow path diameter is smaller than that of the outlet flow path 82.

  In the present embodiment, the outlet channel 82 and the connection channel 91 have substantially the same channel diameter, but the outlet channel 82 may have a smaller channel diameter than the connection channel 91. Good. In such a case, the reduction amount of the flow path diameter of the outlet flow path 82 is set to a range in which the pressure wave can propagate between the fluid ejection opening 96 and the pressure chamber 80.

  The upper case 70 is formed with an inlet channel 81 communicating with the pressure chamber 80, and the liquid supply tube 4 is attached to the inlet channel 81.

  Here, the flow path length from the fluid ejection opening 96 to the deformation surface of the pressure chamber 80 (that is, the surface of the diaphragm 40 on the pressure chamber 80 side) is represented by a distance D.

Next, the configuration of the drive control unit of the present embodiment will be described.
FIG. 3 is a block diagram illustrating a schematic configuration of the drive control unit according to the present embodiment. The drive controller 15 includes a pump drive circuit 152 that controls the drive of the pump 10, a piezoelectric element drive circuit 153 that controls the drive of the piezoelectric element 30, and a control circuit 151 that controls the pump drive circuit 152 and the piezoelectric element drive circuit 153. And is configured. The piezoelectric element driving circuit 153 includes a waveform shape generating circuit (not shown) that generates a predetermined driving waveform of the piezoelectric element 30.

  Here, by operating the injection command changeover switch 25, a predetermined drive waveform is input to the piezoelectric element 30 based on the program of the control circuit 151 to drive the piezoelectric element 30. The pump 10 may be driven simultaneously with the start of driving of the piezoelectric element 30, but the pump 10 drive command is separated from the activation of the piezoelectric element 30, and the pump 10 may be driven before driving the piezoelectric element 30. More desirable.

  Next, the fluid discharge operation of the pulsating flow generation unit 20 in the present embodiment will be described with reference to FIGS. The fluid discharge of the pulsating flow generation unit 20 of the present embodiment is performed by the difference between the synthetic inertance L1 on the inlet flow path 81 side and the synthetic inertance L2 on the outlet flow path 82 side.

First, inertance will be described.
The inertance L is expressed by L = ρ × h / S, where ρ is the density of the fluid, S is the cross-sectional area of the flow path, and h is the length of the flow path. When the pressure difference in the flow path is ΔP and the flow rate of the fluid flowing through the flow path is Q, the relationship of ΔP = L × dQ / dt is derived by modifying the equation of motion in the flow path using the inertance L. It is.

  That is, the inertance L indicates the degree of influence on the time change of the flow rate. The larger the inertance L, the less the time change of the flow rate, and the smaller the inertance L, the greater the time change of the flow rate.

The combined inertance L1 on the inlet channel 81 side is calculated in the range of the inlet channel 81. The synthetic inertance L2 on the outlet channel 82 side is calculated in the range of the outlet channel 82.
In addition, the thickness of the tube wall of the connection flow path tube 90 has sufficient rigidity for the pressure propagation of the fluid.

  In this embodiment, the flow path length and cross-sectional area of the inlet flow path 81 and the outlet flow path 82 are set so that the synthetic inertance L1 on the inlet flow path 81 side is larger than the synthetic inertance L2 on the outlet flow path 82 side. Set the channel length and cross-sectional area.

Subsequently, the fluid ejection operation will be described.
Liquid is always supplied to the inlet channel 81 by the pump 10 at a constant pressure (steady flow rate). As a result, when the piezoelectric element 30 does not operate, the liquid flows into the pressure chamber 80 due to the difference between the discharge force of the pump 10 and the channel resistance on the entire inlet channel side.

  Here, if a drive signal is input to the piezoelectric element 30 and the piezoelectric element 30 is suddenly expanded, the volume of the pressure chamber 80 is reduced, and the pressure in the pressure chamber 80 is changed to the combined inertance on the inlet channel side and the outlet channel side. If L1 and L2 have a sufficient size, they rise rapidly and reach several tens of atmospheres.

  Since this pressure is much larger than the pressure by the pump 10 applied to the inlet channel 81, the inflow of the liquid from the inlet channel 81 into the pressure chamber 80 is reduced by the pressure, and the pressure from the outlet channel 82 is reduced. Outflow increases.

  However, the combined inertance L1 on the inlet channel side is larger than the combined inertance L2 on the outlet channel side, and the amount of liquid discharged from the outlet channel 82 is smaller than the amount of decrease in the flow rate flowing into the pressure chamber 80 from the inlet channel 81. Since the increase amount is larger, a pulsed liquid discharge, that is, a pulsating flow is generated in the connection channel 91. The pressure fluctuation at the time of discharge propagates in the connection flow channel tube 90 (connection flow channel 91), and the liquid is ejected in a pulse form from the fluid ejection opening 96 of the nozzle 95 at the tip.

  Here, since the flow path diameter of the fluid ejection opening 96 is smaller than the flow path diameter of the outlet flow path 82, the liquid has a higher pressure and is ejected at high speed as pulsed droplets.

  On the other hand, the pressure chamber 80 is in a low pressure state immediately after the pressure rises due to the interaction between the decrease in the amount of liquid inflow from the inlet channel 81 and the increase in the outflow of liquid from the outlet channel 82. Then, when the piezoelectric element 30 is restored to its original shape, the liquid in the inlet channel 81 flows before the operation of the piezoelectric element 30 (before expansion) after a predetermined time has elapsed due to both the pressure of the pump 10 and the low pressure state in the pressure chamber 80. ) Returns to the pressure chamber 80 at the same speed.

  If the piezoelectric element 30 is expanded after the flow of the liquid in the inlet channel 81 is restored, pulsed droplets are continuously ejected from the fluid ejection opening 96.

Next, the driving waveform of the piezoelectric element 30 will be described.
FIG. 4 is a drive waveform diagram showing an example of a drive waveform of the piezoelectric element according to the present embodiment. The period T of the drive waveform is a time obtained by combining the sin waveform whose phase is shifted by -90 degrees and offset in the positive voltage direction, and the rest period. That is, if the driving frequency of the piezoelectric element 30 is f, one period T is represented by 1 / f.

  When the flow path length from the fluid ejection opening 96 to the deformation surface of the pressure chamber 80 is a distance D and the sound speed in water in the section of the flow path length is Q, the relational wave between the distance D, the sound speed Q, and the drive frequency f. Can be expressed by n · 2D = Q / f or 2D / Q = n / f (n is a positive integer). Since the pressure wave reaches the fluid ejection opening 96 from the pressure chamber 80 and is reflected back to the pressure chamber 80 (deformation surface), the pressure wave travel distance is twice the distance D. In such a relationship, it can be said that the pressure wave in the distance D section has a resonance relationship with the driving of the piezoelectric element 30. Further, since the period T is represented by T = 1 / f, if the above equation is replaced by T = 1 / f, it can be represented by T = n · 2D / Q.

  Assuming that the piezoelectric element 30 expands when a positive voltage is applied, a section of time t1 (may be expressed as rise time t1) corresponds to a time during which the volume of the pressure chamber 80 is decreased. That is, the internal pressure of the pressure chamber 80 rises during the rise time t1. Further, the section of time t2 (which may be expressed as the fall time t2) is a section in which the electric charge of the piezoelectric element 30 is removed, and the piezoelectric element 30 is reduced. That is, the volume of the pressure chamber 80 increases in the section of the falling time t2.

Here, a waveform of a combination of a triangular driving waveform and a rest period in which the falling time t2 is set to approximately 0 will be considered.
FIG. 5 is a drive waveform diagram showing a combination of a triangular drive waveform and a pause time T = 1 / f. The drive waveform shown in FIG. 5 shows a drive waveform that rapidly increases the volume after the volume of the pressure chamber 80 is reduced (immediately after the rising time t1).

The state at this time will be schematically shown and described.
FIG. 6 is a cross-sectional view schematically showing the state of the liquid in the connection channel (including the outlet channel). When the volume of the pressure chamber 80 is reduced at the rising time t1, the liquid tends to flow toward the fluid ejection opening 96 (in the direction of arrow E) due to the inertance effect. However, as the volume of the pressure chamber 80 is suddenly reduced, an action of drawing the liquid toward the pressure chamber 80 (in the direction of arrow F) occurs. As a result, liquid column separation, which is a space in a vacuum state, is generated in the connection channel tube 90.

  Since the pressure wave does not propagate when the liquid column separation occurs, it is considered that the driving of the piezoelectric element 30 and the period of the pressure wave in the section of distance D are shifted, and the resonance relationship between the driving of the piezoelectric element 30 is lost.

Therefore, when the time during which the volume of the pressure chamber 80 is increased is t2 (corresponding to the fall time t2 in FIG. 4), the drive waveform of the piezoelectric element 30 is set so that t1 ≦ t2 with respect to the rise time t1. It is desirable to form.
By doing so, it is possible to suppress the occurrence of liquid column separation and stably perform strong fluid ejection by the resonance effect.

Further, since the outlet channel 82 is opened in the direction of volume change of the pressure chamber 80, the pressure wave reaches the inside of the pressure chamber from the fluid ejection opening 96, and the deformation surface of the pressure chamber 80 (that is, the diaphragm 40 of the diaphragm 40). The piezoelectric element 30 can be easily driven and controlled to resonate with the pressure reflected by the pressure chamber side surface.
(Embodiment 2)

Next, Embodiment 2 will be described. In the second embodiment, the relationship between the period T, the distance D, the sound speed Q, and the driving frequency f is n · 2D = Q / f or T = n · 2D / Q in the first embodiment. Resonance even if the piezoelectric element 30 is driven within the range of T ± t1 (that is, an error of 2 · t1 is allowed) when the period T is the time during which the volume of the pressure chamber is reduced is t1. It is characterized by its effectiveness.
FIG. 7 is a drive waveform diagram showing the relationship between the timing of the pressure reflected wave and the drive waveform according to the second embodiment.

  Here, considering the case where the basic drive waveform is the same as in FIG. 4, the relationship of n · 2D = Q / f or 2D / Q = n / f is satisfied. In this case, in the first drive waveform, the piezoelectric element 30 is driven only during the rise time t1 to pressurize the pressure chamber 80. Therefore, the timing and time of the pressure reflected wave reflected from the fluid ejection opening 96 by the first drive waveform. Is a period in the range indicated by hatching in the figure, and has at least the same time as the rising time t1. Here, when the waveform of the conceptual pressure reflected wave is displayed in an overlapping manner, it becomes a region represented by diagonal lines in the figure.

  FIG. 8 is a drive waveform diagram showing a specific relationship between the pressure reflected wave and the timing of the drive waveform. That is, the next drive waveform with respect to the first drive waveform also drives the piezoelectric element 30 during the rise time t1 to pressurize the pressure chamber 80. Therefore, there is a resonance effect even if the pressure is applied in a state overlapping with the waveform of the pressure reflected wave. That is, the rise timing of the drive waveform represents that an error in a range twice as long as the rise time t1 with respect to the period T can be allowed. In other words, the drive waveform may be raised in the range of T ± t1 with respect to the basic period T.

  As described above, even when the rise time of the drive waveform is allowed in the range of T ± t1 with respect to the waveform of the pressure reflected wave, the resonance effect can be obtained as in the case of T = n · 2D / Q, which is almost equivalent. A strong pulse flow can be ejected.

When it is considered that at least 50% of the rising timing of the drive waveform overlaps the waveform of the pressure reflected wave, it is more preferable that the period T = 1 / f allows an error range in the range of the rising time t1.
FIG. 9 is a drive waveform diagram showing a state where the rise timing of the drive waveform is in the range of t1 with respect to the waveform of the pressure reflected wave. That is, with respect to the basic period T = 1 / f, it is more preferable that the rising timing of the drive waveform is in the range of T ± t1 · 1/2, which is almost as strong as when T = n · 2D / Q. A pulse stream can be injected.

  In the first and second embodiments described above, the flow path from the outlet flow path 82 to the fluid ejection opening 96 is linearly formed. The path is not necessarily straight but may be bent.

  FIGS. 10-12 is a block diagram which illustrates the Example at the time of forming a connection flow path (namely, connection pipe) by bending. In the first embodiment shown in FIG. 10, an example in which the middle of the connection flow path pipe 90 is bent in a crank shape is shown. Further, the second embodiment shown in FIG. 11 is an example in which the connecting flow channel tube 90 is bent in a U shape so that the nozzle 95 extends in the direction opposite to the opening direction of the outlet flow channel 82, and the embodiment shown in FIG. 3 represents an example in which the connection flow channel tube 90 is formed by being spirally wound.

  Thus, even if the flow path from the outlet flow path 82 to the fluid ejection opening 96 is formed in a shape including a curve, the outlet flow path 82 in the deformation direction of the pressure chamber 80 (that is, the expansion / contraction direction of the piezoelectric element 30). And a strong pulse flow can be ejected if the conditions of the waveform of the pressure reflected wave and the drive timing of the piezoelectric element 30 described in the first and second embodiments are satisfied.

  In addition, the connection flow path tube 90 can be formed in various shapes without departing from the driving conditions described above, and the user can bend the connection flow path tube 90 or connect the connection flow path pipe 90 to the connection flow path tube 90. Such a thing may be adopted. When a tube is used, it is desirable that the tube has rigidity enough to prevent the tube from being deformed by a pressure wave.

  As described above, since the pressure reflected wave and the driving waveform are in a relationship of T = n · 2D / Q, the distance D is inevitably determined by the driving frequency f and the sound velocity Q of the fluid. At this time, it is conceivable that the length of the connection flow path 91 is much longer than the distance from the pulsating flow generation portion 20 that is easy for the user to perform the treatment to the fluid ejection opening portion 96. In such a case, the connection flow path tube 90 is bent as shown in FIGS. 10 to 12, so that the user can easily operate the distance of the fluid ejection opening 96 from the grasped pulsating flow generation unit 20. Thus, the fluid ejecting apparatus 1 that satisfies the above-described conditions can be realized.

  DESCRIPTION OF SYMBOLS 1 ... Fluid ejection apparatus, 30 ... Piezoelectric element, 40 ... Diaphragm, 80 ... Pressure chamber, 82 ... Outlet flow path, 96 ... Fluid ejection opening part.

Claims (3)

A volume changing means for changing the volume of the pressure chamber; an outlet channel opened in the volume changing direction of the pressure chamber; and a fluid ejection opening communicating with the outlet channel. A method of driving a fluid ejection device that changes the volume of the pressure chamber and ejects fluid in a pulse form from the fluid ejection opening,
When the period of the volume change of the pressure chamber is T, the distance from the fluid ejection opening to the deformation surface of the pressure chamber is D, and the sound speed in water in the section of the distance D is Q, the period T, the distance D, and the sound speed The fluid ejecting apparatus driving method, wherein the volume changing unit is driven so that Q satisfies T = n · 2D / Q (n is a positive integer). The method for driving a fluid ejection device according to claim 1,
In the period T, the volume changing means is driven within a range of T ± t1, where t1 is a time during which the volume of the pressure chamber is reduced. In the driving method of the fluid ejection device according to claim 1 or 2,
The fluid ejecting apparatus driving method according to claim 1, wherein the volume changing means is driven so that t1 ≦ t2, where t2 is a time during which the volume of the pressure chamber is increased.

Images