JP2013056015A - Liquid ejecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejecting apparatus in the liquid chamber of which bubbles are hard to accumulate so as to enable the liquid to be stably ejected.SOLUTION: The liquid ejecting apparatus 10 is such as to eject liquid from a nozzle 102, and includes: an inlet flow path 106a to which the liquid is supplied; an outlet flow path 106b which communicates with the nozzle 102; a liquid chamber 110 which is partitioned into a spiral form by deformable partitioning walls 120w between the inlet flow path 106a and the outlet flow path 106b and has a given volume; a piezoelectric element 112 which reduces the volume of the liquid chamber 110 to be smaller than the given volume; and a control part 200 which makes the liquid eject in a pulse mode from the nozzle 102 by driving the piezoelectric element 112 with the liquid filled in the liquid chamber 110 According to such structure, the flow of the liquid in the liquid chamber 110 is restricted along the spiral flow path to inhibit accumulation of air bubbles in a portion where the flow of the liquid is slow, and hence the air bubbles in the liquid chamber can be discharged from the outlet flow path 106b quickly.

Description

  The present invention relates to a liquid ejecting apparatus.

  There has been developed a liquid ejecting apparatus that incises or excises a biological tissue by pressurizing a liquid such as water or physiological saline and ejecting the liquid toward a living tissue from a nozzle having a narrow cross-sectional area. In surgery using such a liquid ejecting apparatus, it is possible to selectively incision or excision only of tissues such as organs without damaging nerves and blood vessels, etc., and there is little damage to surrounding tissues. Can be reduced.

  Further, there has been proposed a liquid ejecting apparatus that enables incision or excision of a living tissue with a small amount of ejection by ejecting liquid in a pulse form instead of simply ejecting liquid continuously from a nozzle (for example, , See Patent Document 1). This liquid ejecting apparatus rapidly increases the pressure in the liquid chamber by rapidly decreasing the volume of the liquid chamber while the liquid chamber is filled with the liquid, and the pressure causes a pulse from the nozzle connected to the liquid chamber. The liquid is jetted in the shape of Subsequently, the volume of the liquid chamber is returned to the original, and the liquid is filled again. By repeating these operations, a pulsed jet can be generated periodically.

JP 2008-082202 A

  However, in such a liquid ejecting apparatus that ejects liquid in a pulsed manner, bubbles that are generated in the liquid chamber due to bubbles that exist in the liquid or gas that has been dissolved in the liquid are retained in the liquid chamber. As a result, there was a problem that the ability of incision and excision deteriorated. That is, as described above, the pulsed jet is generated by reducing the volume of the liquid chamber and pressurizing the liquid in the liquid chamber. Therefore, if there are bubbles in the liquid chamber, the volume of the liquid chamber is decreased. Even if it makes it, it cannot fully pressurize the liquid by the bubble being compressed. For this reason, it has become a problem that the liquid cannot be ejected in a pulse form from the nozzle, and the ability to cut and excise is reduced.

  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 liquid ejecting apparatus according to this application example is a liquid ejecting apparatus that ejects liquid from a nozzle, and includes an inlet flow path to which the liquid is supplied, an outlet flow path that communicates with the nozzle, A liquid chamber having a given volume partitioned in a spiral shape by a deformable partition wall between the inlet channel and the outlet channel, and the volume of the liquid chamber is reduced below the given volume. On the first direction side, a volume changing unit that deforms the liquid chamber, and driving the volume changing unit in a state where the liquid is filled in the liquid chamber, the liquid is ejected in a pulse form from the nozzle. And an injection control means.

  According to this application example, when the volume changing unit is driven in a state where the liquid supplied from the inlet channel is filled in the liquid chamber, the liquid chamber is deformed in the first direction side, and before the volume changing unit is driven. Since the volume of the liquid chamber is reduced, the liquid pressurized in the liquid chamber is ejected from the nozzle through the outlet channel. Inside the liquid chamber, a spiral channel (swirl channel) is formed with a deformable partition wall, and the liquid supplied from the inlet channel flows along the spiral channel, It leads to the outlet channel.

  If the flow of the liquid in the liquid chamber is irregular and there are places where the flow is fast and slow, bubbles tend to stay in the place where the flow is slow, and the presence of such bubbles does not sufficiently increase the pressure in the liquid chamber. Will not be able to jet strongly. Therefore, if a spiral flow path that guides the liquid from the inlet flow path to the outlet flow path is formed in the liquid chamber, the flow of the liquid in the liquid chamber is regulated along the spiral flow path. Therefore, since the liquid flows at a sufficiently high flow velocity in all parts of the liquid chamber, it is possible to suppress the bubbles from staying in the slow-flowing portion and quickly discharge the bubbles in the liquid chamber from the outlet channel. Can do. As a result, the liquid can be stably ejected without being affected by bubbles.

  In addition, since the partition wall forming the spiral flow path is provided so as to be deformable, when the volume of the liquid chamber is reduced by driving the volume changing unit, the spiral partition wall is directed toward the outlet flow path. By deforming the flow path so as to contract, the pressurized liquid in the liquid chamber can be moved toward the outlet flow path, and the liquid can be appropriately ejected.

  Application Example 2 In the liquid ejecting apparatus according to the application example, the volume changing unit includes a piezoelectric element, the volume of the liquid chamber is reduced by extending the piezoelectric element, and the piezoelectric element includes: It is preferable that the liquid chamber is disposed so as to press in a state where the piezoelectric element is not expanded.

  According to such a configuration, the piezoelectric element that reduces the volume of the liquid chamber by stretching has a characteristic that it is strong against an external compressive force but weak against a tensile force. If a tensile force acts on the piezoelectric element, it causes damage. Therefore, even when the piezoelectric element is not expanded, if the piezoelectric element is provided in a state of pressing the liquid chamber, a force in the compression direction can be applied in advance to the piezoelectric element as a reaction force of the pressing. it can. Thereby, when a force in the tensile direction is applied to the piezoelectric element, the force in the tensile direction is reduced, so that the occurrence of breakage of the piezoelectric element due to the action of the tensile force can be reduced.

  Further, even when the piezoelectric element is not expanded, if the piezoelectric element is provided in a state of pressing the liquid chamber, the liquid chamber pressing is started immediately when the piezoelectric element starts to expand. Therefore, there is no stroke loss between the extension of the piezoelectric element and the pressing of the liquid chamber, and there is an effect that the liquid can be efficiently ejected.

  Application Example 3 In the liquid ejecting apparatus according to the application example, it is preferable that a cross-sectional area of the inlet channel is smaller than a cross-sectional area of the outlet channel, and the inlet channel is a capillary.

  In this way, when the volume of the liquid chamber is reduced, the backflow from the inlet channel can be suppressed to increase the pressure in the liquid chamber, and the liquid chamber can easily flow out from the outlet channel.

  Application Example 4 In the liquid ejecting apparatus according to the application example described above, the partition wall forming the liquid chamber faces the first direction side surface or the first direction side surface constituting the liquid chamber. It is preferable that it is provided upright from either one of the two-direction surfaces and the tip is not fixed.

  According to such a configuration, when the volume of the liquid chamber is reduced by driving the volume changing unit, the partition wall can be deformed so that the front end side of the partition wall falls toward the outlet channel. A liquid flow over the wall and toward the outlet channel can be generated. Thus, since the liquid is collected from the surroundings to the outlet channel by the flow crossing the spiral channel, the liquid can be appropriately ejected.

  The partition wall forming the spiral flow path does not necessarily stand from the inner surface of the liquid chamber, and is fixed to either the surface on the first direction side or the surface on the second direction side of the liquid chamber. You may provide in the state which is not done. In this case, when the volume of the liquid chamber is reduced by driving the volume changing unit, the partition wall is deformed toward the outlet channel, and the liquid in the liquid chamber is also moved toward the outlet channel in the center of the liquid chamber. Can do.

  Application Example 5 In the liquid ejecting apparatus according to the application example described above, the partition wall forming the liquid chamber faces the first direction side surface or the first direction side surface constituting the liquid chamber. It is preferable that it is provided in a state where it is erected from any one of the two-direction surfaces and is fixed to the other surface facing the one surface.

  Even in such a configuration, when the volume of the liquid chamber is reduced by driving the volume changing unit, the partition wall having both ends (base and tip) fixed to the liquid chamber is bent toward the outlet channel. By deforming, the liquid in the liquid chamber can be moved toward the outlet channel.

  Application Example 6 In the liquid ejecting apparatus according to the application example described above, it is preferable that the flow path of the liquid chamber has a substantially uniform cross-sectional area.

  If the cross-sectional area of the spiral flow path is made substantially uniform in this way, the liquid supplied to the liquid chamber can flow at a constant flow rate along the spiral flow path. For this reason, bubbles do not stay in a slow flow place, and the bubbles in the liquid chamber can be quickly discharged from the outlet channel by being put on a flow having a constant flow velocity.

  Application Example 7 In the liquid ejecting apparatus according to the application example, the inlet channel is communicated with an outer peripheral edge portion of the liquid chamber, and the outlet channel is communicated with a central portion of the liquid chamber. Are preferred.

  With such a configuration, when the volume of the liquid chamber is reduced by driving the volume changing section, the central portion of the partition wall with both ends (base and tip) fixed to the liquid chamber is the center of the liquid chamber. The liquid in the liquid chamber can be moved toward the outlet channel in the center of the liquid chamber by being deformed so as to bend toward the center. As a result, even if a spiral wall is provided inside the liquid chamber, a liquid flow toward the central outlet channel is generated inside the innermost wall of the spiral partition wall, and the outlet channel Since the liquid is collected from the surroundings, the liquid can be ejected appropriately.

  Application Example 8 In the liquid ejecting apparatus according to the application example, the inlet channel is communicated with a central portion of the liquid chamber, and the outlet channel is communicated with an outer peripheral edge of the liquid chamber. Are preferred.

  With such a configuration, when the volume of the liquid chamber is reduced by driving the volume changing unit, the partition wall with both ends (base and tip) fixed to the liquid chamber is arranged in the outer circumferential direction of the liquid chamber. By deforming so as to bend, the liquid in the liquid chamber can be moved toward the outlet channel on the outer peripheral edge of the liquid chamber. As a result, even if a spiral partition wall is provided inside the liquid chamber, a liquid flow toward the outlet channel on the outer peripheral edge is generated inside the outermost wall of the spiral partition wall, so that the liquid is It can be injected strongly.

FIG. 3 is an explanatory diagram illustrating a main configuration of a representative example of the liquid ejecting apparatus according to the first embodiment. The exploded assembly figure which shows the cross section of a pulsation generation | occurrence | production part. Explanatory drawing which showed the shape of the flow-path formation member. Explanatory drawing which showed a mode that the pulsation generation | occurrence | production part ejected the liquid (state which does not drive a piezoelectric element). Explanatory drawing which showed a mode that the pulsation generation | occurrence | production part ejected the liquid (state which driven the piezoelectric element and pressed the liquid chamber). It is explanatory drawing which showed the internal structure of the pulsation generation | occurrence | production part of a 1st modification, (a) is the state which the piezoelectric element is not driving, (b) is the state which the piezoelectric element extended | stretched by application of the drive voltage. It is explanatory drawing which showed the internal structure of the pulsation generation | occurrence | production part of a 2nd modification, (a) is the state which the piezoelectric element is not driving, (b) is the state which the piezoelectric element extended | stretched by application of the drive voltage. FIG. 9 is an exploded view illustrating a part of a cross section of a pulsation generating unit according to a second embodiment. Explanatory drawing which showed the shape of the flow-path formation member which concerns on Embodiment 2. FIG. Explanatory drawing which showed a mode that the pulsation generating part which concerns on Embodiment 2 injects a liquid.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The drawings referred to in the following description are schematic views in which the vertical and horizontal scales of each member or part are different from actual ones in order to make each member a recognizable size.
(Embodiment 1)

First, the configuration of the liquid ejecting apparatus 10 according to a representative example of the first embodiment will be described.
FIG. 1 is an explanatory diagram showing a main configuration of a representative example in the liquid ejecting apparatus 10 of the present embodiment. The liquid ejecting apparatus 10 of the present embodiment accommodates a pulsation generator 100 that ejects a liquid such as water or physiological saline in a pulsed manner, a liquid supply means 300 that supplies the liquid to the pulsation generator 100, and a liquid to be ejected. And a control unit 200 as an ejection control unit that controls the operation of the pulsation generating unit 100 and the liquid supply unit 300.

  The pulsation generator 100 has a structure in which the second case 106 and the first case 108 are overlapped and screwed together, and the front surface of the second case 106 (the surface opposite to the surface mated with the first case 108). ) Is connected to a circular liquid jet pipe 104, and a nozzle 102 is provided at the tip of the liquid jet pipe 104.

  A liquid chamber 110 filled with a liquid is provided on the mating surface of the second case 106 and the first case 108, and the liquid chamber 110 communicates with the nozzle 102 via the liquid ejection pipe 104. . In addition, a laminated piezoelectric element 112 as a volume changing unit is provided inside the first case 108, and a driving voltage waveform is applied from the control unit 200 to drive (expand and contract) the piezoelectric element 112. Thus, the volume of the liquid chamber 110 can be changed, and the liquid in the liquid chamber 110 can be ejected in a pulse form from the nozzle 102. The detailed configuration of the pulsation generator 100 will be described later with reference to FIG.

  The liquid supply means 300 is connected to the liquid container 306 via the first connection tube 302, and supplies the liquid sucked from the liquid container 306 to the liquid chamber 110 of the pulsation generator 100 via the second connection tube 304. To do. Although not shown in the drawing, the liquid supply means 300 of the present embodiment has a configuration in which two pistons slide in the cylinder, and the pulsation generator 100 is controlled by appropriately controlling the moving speeds of both pistons. It is possible to stably pump the liquid toward the head.

  The control unit 200 controls the operation of the piezoelectric element 112 built in the pulsation generating unit 100 and the operation of the liquid supply means 300. In the liquid ejecting apparatus 10 of the present embodiment, the flow rate of the liquid supplied from the liquid supply unit 300, the waveform of the drive voltage applied to the piezoelectric element 112, the maximum voltage value, and the frequency are changed to change the amount of liquid supplied from the nozzle 102. It is possible to change the injection mode.

Next, the configuration of the pulsation generator 100 will be described with reference to the drawings.
FIG. 2 is an exploded view showing a cross section of the pulsation generator 100. As described above, the pulsation generator 100 is configured by screwing the second case 106 and the first case 108 together. The first case 108 is formed with a circular shallow recess 108c substantially at the center of the surface mating with the second case 106. A circular cross-sectional through-hole penetrating the first case 108 is formed at the center of the recess 108c. 108h is formed. A circular diaphragm 114 formed of a thin metal plate or the like is adhered and fixed to the bottom surface of the recess 108c so as to close the through hole 108h.

  The piezoelectric element 112 is housed in the through hole 108 h closed by the diaphragm 114, and the opening of the through hole 108 h is closed by the third case 118. A circular reinforcing plate 116 is inserted between the piezoelectric element 112 and the diaphragm 114. When the piezoelectric element 112 is housed in the through hole 108h of the first case 108 and the through hole 108h is closed with the third case 118, the diaphragm 114, the reinforcing plate 116, the piezoelectric element 112, and the third case The thickness of the reinforcing plate 116 is set so that 118 is just in contact. Note that one end of the piezoelectric element 112 is fixed to the third case 118, and the other end of the piezoelectric element 112 is fixed to the reinforcing plate 116. The surface of the reinforcing plate 116 opposite to the piezoelectric element 112 is fixed to the diaphragm 114.

  From above the diaphragm 114 (the side facing the second case 106), the flow path forming member 120 in which the partition wall 120w is erected on the first direction side on one side of the circular support plate 120b, and the support plate 120b is connected to the diaphragm 114. Are fitted into the recess 108c so as to overlap with each other. The surface of the support plate 120b opposite to the surface on which the partition wall 120w is erected is fixed to the diaphragm 114, and the thickness of the support plate 120b and the diaphragm 114 is the same as the depth of the recess 108c. It is formed to become. The flow path forming member 120 is formed of a flexible material so as to be deformable. The shape of the partition wall 120w of the flow path forming member 120 will be described later with reference to FIG.

  On the other hand, in the second case 106, a circular shallow recess 106c is formed on the surface where it is combined with the first case 108. The inner diameter of the recess 106c is smaller than the outer diameter of the support plate 120b of the flow path forming member 120 fitted in the first case 108, and is large enough to include the partition wall 120w erected on the support plate 120b. Is set. The depth of the recess 106c is set to be substantially the same as the height of the partition wall 120w.

  When the second case 106 and the first case 108 are screwed together, the liquid is formed by the recess 106c of the second case 106 and the support plate 120b of the flow path forming member 120 provided on the first case 108 side. A chamber 110 is formed. Further, the tip of the partition wall 120 w of the flow path forming member 120 (the end facing the second case 106) is fixed to the recess bottom surface 106 d of the recess 106 c of the second case 106, A flow path partitioned by the partition wall 120w is formed.

  However, on the contrary, the support plate 120b of the flow path forming member 120 is fixed to the recess bottom surface 106d of the recess 106c of the second case 106, and the second case 106 and the first case 108 are screwed together. In the state, the tip of the partition wall 120w of the flow path forming member 120 (the side facing the first case 108: the end in the second direction) may be fixed to the diaphragm 114 provided in the first case 108. .

  In addition, the second case 106 has an inlet channel 106 a that guides the liquid supplied from the second connection tube 304 connected to the second case 106 to the liquid chamber 110, and the liquid pressurized in the liquid chamber 110. An outlet channel 106 b that leads to the liquid jet pipe 104 is provided. Among these, the inlet channel 106a is opened at a peripheral position of the recess 106c, and the outlet channel 106b is opened at the center of the recess 106c.

  The inner diameter of the liquid ejection pipe 104 connected to the front surface of the second case 106 (the surface opposite to the surface mated with the first case 108) is set larger than the inner diameter of the outlet channel 106b. In addition, a nozzle 102 having a liquid ejection opening having an inner diameter smaller than that of the outlet channel 106b is inserted at the tip of the liquid ejection pipe 104. Therefore, the flow path through which the liquid flowing out of the liquid chamber 110 travels increases in cross-sectional area when it reaches the liquid ejection pipe 104 through the outlet flow path 106b, and the cross-sectional area again at the nozzle 102 at the tip of the liquid ejection pipe 104. Is becoming narrower.

Next, the configuration of the flow path forming member 120 will be described with reference to FIG.
FIG. 3 is an explanatory view showing the shape of the flow path forming member 120. FIG. 3 shows a state in which the flow path forming member 120 is viewed from the side facing the second case 106. As illustrated, the support plate 120b of the flow path forming member 120 is formed in the same circular shape as the diaphragm 114, and the support plate 120b is formed on the upper surface of the support plate 120b (the surface facing the second case 106). A partition wall 120w is erected in a spiral shape that swirls while being wound toward the center of the wall.

  The spiral partition wall 120w is formed such that the outermost peripheral surface of the outermost wall is in contact with the inner peripheral surface of the recess 106c, and the partition wall 120w wound in multiple (five layers in the example of FIG. 3) The distance from the partition wall 120w is set to be almost constant. As described above, when the second case 106 and the first case 108 are screwed together, the partition wall 120w causes the liquid chamber 110 to have a spiral flow path (turning from the peripheral edge toward the center) ( Hereinafter, a spiral flow path is formed.

  Further, as described above, the inlet channel 106a and the outlet channel 106b are connected to the recess 106c of the second case 106, and the second case 106 and the first case 108 are aligned at an appropriate position and screwed. When stopped, the outlet channel 106b opens at the center-side contact portion of the spiral flow path formed inside the liquid chamber 110, and the inlet channel 106a opens at the edge-side contact portion of the spiral flow path. ing.

In the pulsation generator 100 configured as described above, it is possible to eject liquid from the nozzle 102 in a pulsed manner by applying a drive voltage waveform to the piezoelectric element 112 to drive (expand or contract) the piezoelectric element 112. It has become. Below, the operation | movement which the pulsation generation | occurrence | production part 100 injects a liquid is demonstrated.
(Liquid ejection operation according to Embodiment 1)

Next, the liquid ejecting operation by the pulsation generator 100 according to this embodiment will be described.
4 and 5 are explanatory views showing a state in which the pulsation generating unit 100 ejects liquid. FIG. 4 shows a state in which the piezoelectric element 112 is not driven (before a drive voltage waveform is applied to the piezoelectric element 112). State). As shown in FIG. 4A, the liquid supplied from the liquid supply means 300 to the pulsation generating unit 100 via the second connection tube 304 flows into the liquid chamber 110 through the inlet channel 106a. The liquid chamber 110 is filled with liquid. In addition, the arrow of the broken line in a figure represents the flow of the liquid typically.

  Further, as described above, a spiral flow path is formed in the liquid chamber 110 by being partitioned by the partition wall 120w of the flow path forming member 120. As shown in FIG. The liquid that flows in from the inlet channel 106a that opens to the peripheral edge of the liquid chamber 110 is guided to the outlet channel 106b that opens in the center of the liquid chamber 110 while swirling along the spiral channel (partition wall 120w). . By restricting the flow of the liquid along the spiral flow path in this way, there are no places where the flow is fast and slow in the liquid chamber 110, and the liquid flowing in from the inlet flow path 106a is allowed to flow out. Can flow at a substantially uniform flow rate.

  As described above, since the liquid is supplied from the liquid supply means 300 without interruption, when the liquid chamber 110 is filled with the liquid, the liquid chamber 110 can be filled even if the piezoelectric element 112 is not driven. The liquid is pushed out toward the liquid jet pipe 104 through the outlet channel 106b.

  FIG. 5 shows a state in which the liquid element 110 is pressed by driving the piezoelectric element 112. When a drive voltage waveform is applied to the piezoelectric element 112 in a state where the liquid chamber 110 is filled with the liquid, the piezoelectric element 112 expands as the drive voltage increases, as shown in FIG. The diaphragm 114 and the support plate 120 b of the flow path forming member 120 are pressed toward the liquid chamber 110. As a result, the volume of the liquid chamber 110 is reduced. As a result, the liquid in the liquid chamber 110 is pressurized. The liquid pressurized in the liquid chamber 110 is ejected in a pulse form from the nozzle 102 through the outlet channel 106b and the liquid ejecting pipe 104, as indicated by the dashed arrows in FIG. .

  Note that the liquid chamber 110 communicates with two channels, an inlet channel 106a and an outlet channel 106b. Therefore, it is considered that the liquid pressurized in the liquid chamber 110 flows out not only from the outlet channel 106b but also from the inlet channel 106a. However, since the ease of liquid flow in the flow path is determined by the cross-sectional area of the flow path, the length of the flow path, etc., the cross-sectional areas and lengths of the inlet flow path 106a and the outlet flow path 106b should be set appropriately. For example, it is possible to make it easier for the liquid to flow out of the outlet channel 106b than the inlet channel 106a. For example, in this embodiment, the outlet channel 106b has a capillary shape with a diameter of about 1 mm and the inlet channel 106a has a diameter of about 0.3 mm. Therefore, the backflow from the inlet channel 106a is suppressed.

  In addition, in the inlet channel 106 a, there is a flow in which the liquid pressure-fed from the liquid supply means 300 tends to flow into the liquid chamber 110, which prevents the liquid from flowing out of the liquid chamber 110. In 106b, there are few factors that increase the resistance and fluid inertia that hinder the outflow of the liquid in the liquid chamber 110. Therefore, the liquid pressurized in the liquid chamber 110 flows out of the outlet channel 106 b exclusively and is ejected from the nozzle 102 at the tip through the liquid ejection pipe 104.

  As described above, the interior of the liquid chamber 110 according to the present embodiment is partitioned in a spiral shape by the partition wall 120 w of the flow path forming member 120. However, when the volume of the liquid chamber 110 decreases due to the expansion of the piezoelectric element 112, the liquid does not flow along the spiral partition wall 120w (swirl channel), but the partition wall 120w is located on the outlet channel 106b side. The liquid in the liquid chamber 110 moves toward the center of the liquid chamber 110 by being deformed toward (the central portion of the liquid chamber 110). This point will be supplementarily described.

  First, considering an example of the partition wall 120w that forms the innermost wall of the spiral-shaped partition wall 120w that is wound in multiple layers, the outlet channel 106b is located at the center of the liquid chamber 110 inside the innermost partition wall 120w. Therefore, when the volume of the liquid chamber 110 decreases, an increase in pressure is suppressed by the liquid flowing out from the outlet channel 106b.

  On the other hand, outside the partition wall 120w, the inlet channel 106a is a capillary, and the pressure rises compared to the inside of the partition wall 120w to suppress the outflow of fluid. Since the partition wall 120w is formed of a flexible material so as to be deformable, the partition wall 120w is deformed by pressing the partition wall 120w from the high pressure outside toward the low pressure inside, and the pressure difference between the inside and the outside is increased. Try to decrease. In addition, since the partition wall 120w of this embodiment is erected from the support plate 120b and the tip is fixed to the recess bottom surface 106d of the recess 106c of the second case 106, it is shown in FIG. As described above, the central portion of the partition wall 120w is deformed so as to be bent from the outside by being pushed from the outside.

  The pressure difference between the inner side and the outer side of the partition wall 120w is not only the innermost partition wall 120w but also the innermost partition wall 120w that is deformed inward to reduce the outer pressure. It also occurs in the heavy partition wall 120w and similarly propagates to the triple partition wall 120w. Therefore, the spiral partition wall 120w is deformed so as to contract the spiral toward the center of the liquid chamber 110 as a whole. As shown in FIG. 5A, the displacement of the partition wall 120w is the largest in the innermost partition wall 120w having a small inner diameter.

  Thus, when the volume of the liquid chamber 110 decreases due to the extension of the piezoelectric element 112, the central portion of the spiral partition wall 120 w is deformed so as to bend toward the center of the liquid chamber 110, thereby This liquid moves toward the outlet channel 106b in the center of the liquid chamber 110 as shown in FIG.

  Here, when the volume of the liquid chamber 110 decreases due to the expansion of the piezoelectric element 112, a corresponding amount of liquid is collected in the outlet channel 106 b and pushed out, so that the liquid is discharged from the nozzle 102 at the tip of the liquid ejection pipe 104. Be injected. At this time, it is considered that the spiral partition wall 120w in the liquid chamber 110 becomes an obstacle, and a sufficient amount of liquid cannot be collected from the periphery to the central outlet channel 106b. However, in the pulsation generating unit 100 of the present embodiment, the displacement amount due to the expansion of the piezoelectric element 112 is small, and the amount of liquid ejected in one pulse (ejection amount) is relative to the volume of the liquid chamber 110. Since the partition wall 120w is slightly deformed toward the center of the liquid chamber 110, a sufficient amount of liquid is collected from the surroundings in the outlet channel 106b.

For example, when the injection amount V is 1/100 of the volume of the liquid chamber 110, the inner radius of the liquid chamber 110 is R, and the thickness of the liquid chamber 110 (depth of the recess 106c) is H.
V = πR ² H / 100 Formula (1)
It can be expressed as.

The innermost inner radius of the spiral partition wall 120w is r, and the innermost partition wall 120w is displaced by the distance s toward the center of the liquid chamber 110, and is collected in the outlet channel 106b. Assuming that the pushed amount of liquid is ejected from the nozzle 102, the ejection amount V is the difference between the volume V1 inside the innermost contour before deformation and the volume V2 inside the innermost contour after deformation. From that
V1 = πr ² H
V2 = π (rs) ² H
V = V1−V2 = πH {r ² − (r ² −2rs + s ² )}
= ΠH (2rs−s ² )
It can be expressed as.

Here, if the distance s is a slight displacement, s ² is a very small value. Therefore,
V≈2πrsH Formula (2)
And can be approximated.

For example, when the inner radius r of the innermost partition wall 120w is set to half (1/2) of the inner radius R of the liquid chamber 110, the above equations (1) and (2) From the two equations
2π (R / 2) sH = πR ² H / 100 (3)
s = R / 100 Formula (4)
The innermost partition wall 120w is slightly displaced on the scale of 1/100 of the inner radius of the liquid chamber 110 toward the center of the liquid chamber 110, so that the liquid corresponding to the ejection amount is discharged to the outlet channel 106b. Therefore, the spiral partition wall 120w in the liquid chamber 110 is not hindered when the liquid is ejected.

  After the liquid is ejected in this manner, the piezoelectric element 112 contracts and returns to its original length due to a decrease in the driving voltage. Accordingly, the volume of the liquid chamber 110 is restored to the original volume. Further, the liquid supplied from the liquid supply means 300 to the liquid chamber 110 flows along the spiral flow path (partition wall 120w) to fill the liquid chamber 110, and the partition wall 120w in the liquid chamber 110 is also upright from the original. Restore state. As a result, the state before the piezoelectric element 112 shown in FIG. 4 is driven is restored.

  Then, when the piezoelectric element 112 expands again due to the increase of the drive voltage, the liquid pressurized in the liquid chamber 110 is ejected from the nozzle 102 as shown in FIG. By repeating such an operation, in the pulsation generator 100 of this embodiment, it is possible to eject liquid from the nozzle 102 in a pulse shape.

  As described above, in the liquid ejecting apparatus 10 of the present embodiment, the spiral flow path partitioned by the partition wall 120 w is formed inside the liquid chamber 110, and the inlet flow opening at the peripheral edge of the liquid chamber 110 is formed. The liquid flowing in from the channel 106a flows along the spiral flow path (partition wall 120w) to the outlet flow path 106b opened at the center of the liquid chamber 110, so that bubbles do not easily stay in the liquid chamber 110. Is possible.

  Bubbles in the liquid chamber 110 ride on the liquid flow and are discharged from the outlet channel 106b. However, the configuration in which the inlet channel 106a and the outlet channel 106b are simply connected to the liquid chamber 110 as in the prior art. Then, in the liquid chamber 110, the location where the flow of the liquid is fast and the location where the flow is slow tend to occur, and bubbles may stay in the location where the flow is slow. If bubbles exist in the liquid chamber 110, the pressure of the liquid does not rise sufficiently, and the liquid cannot be ejected properly. On the other hand, if the spiral flow path is formed inside the liquid chamber 110, the flow of the liquid in the liquid chamber 110 can be restricted to a constant flow along the spiral flow path, so that the flow is slow. The bubbles do not stay in the place, and the bubbles in the liquid chamber 110 can be easily discharged. As a result, stable liquid ejection can be maintained.

  In addition, since the partition wall 120w that forms the spiral flow path inside the liquid chamber 110 is provided so as to be deformable with a flexible material, the piezoelectric element 112 extends to reduce the volume of the liquid chamber 110. At that time, the central portion of the spiral partition wall 120w is deformed so as to bend toward the center of the liquid chamber 110, so that the pressurized liquid in the liquid chamber 110 is discharged as in the case where there is no partition wall 120w. The liquid chamber 110 can move toward the center. Therefore, a liquid flow toward the outlet channel 106b opening in the center is generated inside the innermost wall of the spiral partition wall 120w, and the liquid is collected from the surroundings in the outlet channel 106b. As described above, in the liquid ejecting apparatus 10 of the present embodiment, the partition wall 120w is provided inside the liquid chamber 110, but the partition wall 120w is not hindered when ejecting the liquid, and the liquid is ejected appropriately. can do.

In the pulsation generator 100 according to the first embodiment described above, there are several modifications. Hereinafter, these modified examples will be described. In the description of the modified example, the same components as those of the first embodiment described above are denoted by the same reference numerals as those of the first embodiment described above, and detailed description thereof is omitted.
(First modification)

  In the above-described embodiment (see FIG. 4), the partition wall 120w of the flow path forming member 120 is erected from the support plate 120b, and the tip is fixed to the concave bottom surface 106d of the second case 106. . However, the front end of the partition wall 120w is not necessarily fixed to the concave bottom surface 106d of the second case 106.

  FIG. 6 is an explanatory diagram showing the internal structure of the pulsation generator 100 of the first modification. FIG. 6A shows a state in which the piezoelectric element 112 is not driven, and FIG. 6B shows a state in which the piezoelectric element 112 is expanded by applying a drive voltage. As shown in FIG. 6A, the pulsation generator 100 of the first modification also has a spiral partition wall 120w on the support plate 120b, as in the above-described embodiment (see FIG. 4). A standing channel forming member 120 is provided. In the liquid chamber 110, a spiral flow path partitioned by a partition wall 120w is formed. However, in the first modification, unlike the embodiment described above, the tip of the partition wall 120w (the side facing the second case 106: the end in the first direction) is fixed to the concave bottom surface 106d of the second case 106. In addition, a slight gap is provided between the front end of the partition wall 120w and the concave bottom surface 106d.

  In the pulsation generating unit 100 of the first modified example, as in the above-described embodiment, the liquid flowing in from the inlet channel 106a that opens at the peripheral edge of the liquid chamber 110 is a spiral channel (partition wall 120w). The liquid chamber 110 is filled with the liquid by flowing to the central outlet channel 106b while swirling along. Note that since the gap between the tip of the partition wall 120w and the bottom surface 106d of the recess is very small, the liquid flowing into the liquid chamber 110 flows exclusively along the spiral flow path.

  When the piezoelectric element 112 is expanded by applying the drive voltage in a state where the liquid chamber 110 is filled with the liquid in this manner, the volume of the liquid chamber 110 is reduced and the liquid in the liquid chamber 110 is pressurized. At this time, as described above, a pressure difference is generated between the inside and the outside of the partition wall 120w, so that the partition wall 120w is pushed and deformed from the high pressure outside toward the low pressure inside. In the pulsation generator 100 of the first modification, the tip of the partition wall 120w is not fixed to the recess 106c of the second case 106, so that the tip side of the partition wall 120w is the liquid chamber 110 as shown in FIG. Deforms to fall toward the center of the.

  When the leading end side of the partition wall 120w falls toward the center of the liquid chamber 110 in this way, the liquid outside the partition wall 120w flows over the partition wall 120w and flows inward, so that the spiral flow is generated inside the liquid chamber 110. A liquid flow is generated across the path toward the central outlet channel 106b.

  As described above, in the pulsation generating unit 100 of the first modified example, the tip of the partition wall 120w is not fixed to the concave bottom surface 106d of the second case 106, but when the liquid chamber 110 is filled with liquid. As in the above-described embodiment, the flow of the liquid in the liquid chamber 110 can be restricted to a constant flow velocity along the spiral flow path formed by the partition wall 120w. Therefore, the bubbles do not stay in a place where the flow is slow, and the bubbles in the liquid chamber 110 can be quickly discharged.

Further, when the piezoelectric element 112 expands and the volume of the liquid chamber 110 decreases, the tip of the partition wall 120 w that is not fixed to the concave bottom surface 106 d of the second case 106 falls down toward the center of the liquid chamber 110. As a result, a liquid flow is generated inside the liquid chamber 110 and moves over the partition wall 120w toward the central outlet channel 106b. As described above, the liquid is collected from the surroundings to the central outlet flow path 106b by the flow crossing the spiral flow path, so that the liquid can be appropriately ejected.
(Second modification)

  Next, the pulsation generator 100 according to the second modification will be described. In the first modification described above, the partition wall 120w of the flow path forming member 120 is erected from the support plate 120b. However, the partition wall 120w does not necessarily stand from the support plate 120b.

  FIG. 7 is an explanatory diagram showing the internal structure of the pulsation generator 100 according to the second modification. FIG. 7A shows a state in which the piezoelectric element 112 is not driven, and FIG. 7B shows a state in which the piezoelectric element 112 is expanded by applying a drive voltage. As shown in FIG. 7A, also in the pulsation generating unit 100 of the second modified example, a spiral flow partitioned by a spiral partition wall 120w is provided in the liquid chamber 110 as in the above-described embodiment. A road is formed. The partition wall 120w is not fixed to the recess bottom surface 106d of the second case 106, and a slight gap is provided between the partition wall 120w and the recess 106c. In addition, the entire partition wall 120w is not erected from the support plate 120b, but only the outermost portion of the spiral-shaped partition wall 120w wound in multiple layers is erected on the support plate 120b. (Refer FIG. 3), although the remaining part is a series in a spiral shape, it is not fixed to the support plate 120b.

  Also in the pulsation generating unit 100 of the second modified example, when the liquid chamber 110 is filled with the liquid, the liquid flow in the liquid chamber 110 is caused by the partition wall 120w as in the above-described embodiment. Since the flow is restricted to a constant flow along the spiral flow path formed, it is possible to quickly discharge the bubbles in the liquid chamber 110 on the flow.

  On the other hand, as shown in FIG. 7B, when the volume of the liquid chamber 110 decreases due to the expansion of the piezoelectric element 112 and a pressure difference occurs between the inside and the outside of the partition wall 120w as described above, the pressure is high. The partition wall 120w is pushed from the outside toward the inside where the pressure is low. At this time, the portion of the spiral partition wall 120w that is not fixed to the support plate 120b moves toward the center of the liquid chamber 110 so that the mainspring is just wound up. The liquid moves toward the center of the liquid chamber 110. In addition, the liquid flows toward the central outlet channel 106b so as to cross the spiral wall 120w over the partition wall 120w, and the liquid is collected from the surroundings to the outlet channel 106b. can do.

  Although various embodiments of the liquid ejecting apparatus 10 of the present invention have been described above, the present invention is not limited to all the above-described embodiments, and can be implemented in various modes without departing from the gist thereof. It is.

  For example, in the above-described embodiments and modifications, the outlet channel 106b is provided at the center of the concave portion 106c constituting the liquid chamber 110 in order to efficiently guide the liquid supplied to the liquid chamber 110 to the outlet channel 106b. It was set as the structure opened to a position. However, the position at which the outlet channel 106b opens is not limited to the central position of the recess 106c, but at least the outlet channel 106b opens at a position closer to the center of the recess 106c than the inlet channel 106a. It only has to be.

In the above-described embodiment and modification, a spiral flow path is formed in the liquid chamber 110 by the partition wall 120w. However, the flow path formed inside the liquid chamber 110 is not particularly limited as long as it has a shape that turns from the peripheral portion of the liquid chamber 110 toward the center, and for example, deformation such as a zigzag folded shape may be added.
(Embodiment 2)

  Next, the liquid ejecting apparatus 10 according to the second embodiment will be described. In the first embodiment and the modification described above, the outlet channel 106 b communicates with the central portion of the liquid chamber 110 formed in a spiral shape, and the inlet channel 106 a communicates with the outer peripheral edge of the liquid chamber 110. In contrast, the second embodiment is characterized in that the outlet channel 106b communicates with the outer peripheral edge of the liquid chamber 110 formed in a spiral shape, and the inlet channel 106a communicates with the central portion of the liquid chamber 110. . Therefore, in the description of the second embodiment, the same components as those of the first embodiment described above are denoted by the same reference numerals as those of the first embodiment described above, and detailed description thereof is omitted.

  FIG. 8 is an exploded view showing a part of a cross section of the pulsation generator 100 according to the second embodiment. The pulsation generator 100 is formed with a circular shallow recess 108c in the approximate center of the surface where the first case 108 and the second case 106 are combined, and the bottom surface of the recess 108c closes the through hole 108h. A circular diaphragm 114 formed of a thin metal plate or the like is adhered and fixed.

  The piezoelectric element 112 is accommodated in the through hole 108 h closed by the diaphragm 114. A circular reinforcing plate 116 is inserted between the piezoelectric element 112 and the diaphragm 114. The thickness of the reinforcing plate 116 is set so that the diaphragm 114, the reinforcing plate 116, the piezoelectric element 112, and the third case 118 (see FIG. 2) are just in contact with each other. Note that one end of the piezoelectric element 112 is fixed to the third case 118, and the other end of the piezoelectric element 112 is fixed to the reinforcing plate 116. Further, the surface of the reinforcing plate 116 opposite to the piezoelectric element 112 is fixed to the diaphragm 114.

  From above the diaphragm 114 (on the side facing the second case 106), the flow path forming member 120 in which the partition wall 120w is erected on one surface of the circular support plate 120b so that the support plate 120b overlaps the diaphragm 114. It is fitted in the recess 108c. The surface of the support plate 120b opposite to the surface on which the partition wall 120w is erected is fixed to the diaphragm 114, and the thickness of the support plate 120b and the diaphragm 114 is the same as the depth of the recess 108c. It is formed to become. The flow path forming member 120 is formed of a flexible material so as to be deformable. The shape of the partition wall 120w of the flow path forming member 120 will be described later with reference to FIG.

  On the other hand, in the second case 106, a circular shallow recess 106c is formed on the surface where it is combined with the first case 108. When the second case 106 and the first case 108 are screwed together, the liquid is formed by the recess 106c of the second case 106 and the support plate 120b of the flow path forming member 120 provided on the first case 108 side. A chamber 110 is formed. Furthermore, the tip of the partition wall 120w of the flow path forming member 120 (the side facing the second case 106: the end portion on the first direction side) is fixed to the recess bottom surface 106d of the recess 106c of the second case 106, and the liquid chamber A spiral flow path partitioned by a partition wall 120w is formed inside 110.

  However, on the contrary, the support plate 120b of the flow path forming member 120 is fixed to the recess bottom surface 106d of the recess 106c of the second case 106, and the second case 106 and the first case 108 are screwed together. In the state, the tip of the partition wall 120w of the flow path forming member 120 (the side facing the first case 108: the end in the second direction) may be fixed to the diaphragm 114 provided in the first case 108. .

  An inlet channel 106a communicates with the central portion of the spiral liquid chamber 110, and an outlet channel 106b communicates with the outer peripheral edge. A first connection tube 304 is connected to the inlet channel 106a, and a liquid ejection pipe 104 is connected to the outlet channel 106b.

Next, the configuration of the flow path forming member 120 will be described with reference to FIG.
FIG. 9 is an explanatory view showing the shape of the flow path forming member 120. FIG. 9 shows a state where the flow path forming member 120 is viewed from the side facing the second case 106. As illustrated, the support plate 120b of the flow path forming member 120 is formed in the same circular shape as the diaphragm 114, and the support plate 120b is formed on the upper surface of the support plate 120b (the surface facing the second case 106). A partition wall 120w is erected in a spiral shape that swirls while being wound toward the center of the wall.

  The spiral-shaped partition wall 120w is formed so that a part of the outer peripheral surface of the outermost wall is in contact with the inner peripheral surface of the recess 106c, and is further divided into multiple (five layers in the example of FIG. 3). The interval between 120w and the partition wall 120w is set to be substantially constant. As described above, when the second case 106 and the first case 108 are screwed together, the spiral flow path toward the outer peripheral edge while turning from the center portion is formed inside the liquid chamber 110 by the partition wall 120w. It is formed.

  Further, as shown in FIG. 8A, the recess 106c of the second case 106 is connected to the inlet channel 106a and the outlet channel 106b, and the second case 106 and the first case 108 are appropriately connected. When the screws are screwed together at various positions, the inlet channel 106a opens at the center of the spiral channel formed inside the liquid chamber 110, and the outlet channel 106b at the corner of the spiral channel on the outer peripheral edge side. Is designed to open.

Also in the pulsation generator 100 configured as described above, the liquid can be ejected in a pulse form from the nozzle 102 by applying a drive voltage waveform to the piezoelectric element 112 to drive (expand and contract) the piezoelectric element 112. It is possible. In addition, the flow direction of the liquid in the liquid chamber 110 is represented by a broken line in FIG.
(Liquid ejection operation according to Embodiment 2)

Next, the liquid ejecting operation by the pulsation generator 100 according to this embodiment will be described.
FIG. 10 is an explanatory diagram showing a state in which the pulsation generator 100 ejects liquid. Although not shown, in a state where the piezoelectric element 112 is not driven (a state where no driving voltage is applied), the liquid supplied from the liquid supply unit 300 to the pulsation generating unit 100 via the second connection tube 304 is the inlet channel. The liquid chamber 110 is filled with the liquid by flowing into the liquid chamber 110 through 106a.

  A spiral flow path is formed inside the liquid chamber 110 by being partitioned by the partition wall 120 w of the flow path forming member 120, and the liquid that has flowed from the inlet flow path 106 a that opens at the center of the liquid chamber 110. Is guided along the spiral flow path (partition wall 120w) to the outlet flow path 106b that opens to the outer peripheral edge of the liquid chamber 110. By restricting the flow of the liquid along the spiral flow path in this way, there are no places where the flow is fast and slow in the liquid chamber 110, and the liquid flowing in from the inlet flow path 106a is allowed to flow out. Can flow at a substantially uniform flow rate.

  In addition, since the liquid is supplied from the liquid supply means 300 at a substantially constant pressure without interruption, when the liquid chamber 110 is filled with the liquid, even if the piezoelectric element 112 is not driven, The liquid is pushed out toward the liquid jet pipe 104 through the outlet channel 106b.

  FIG. 10 shows a state where the piezoelectric element 112 is driven and the liquid chamber 110 is pressed. When a drive voltage waveform is applied to the piezoelectric element 112 in a state where the liquid chamber 110 is filled with the liquid, as shown in FIG. 10A, the piezoelectric element 112 expands due to the increase of the drive voltage, and the reinforcing plate 116 is The diaphragm 114 and the support plate 120 b of the flow path forming member 120 are pressed toward the liquid chamber 110. As a result, the volume of the liquid chamber 110 is reduced. As a result, the liquid in the liquid chamber 110 is pressurized. The liquid pressurized in the liquid chamber 110 is ejected in a pulse form from the nozzle 102 via the outlet channel 106b and the liquid ejection pipe 104, as indicated by the dashed arrows in FIG. .

  The liquid chamber 110 is connected to two flow paths, an inlet flow path 106a and an outlet flow path 106b. Therefore, it is considered that the liquid pressurized in the liquid chamber 110 flows out not only from the outlet channel 106b but also from the inlet channel 106a. However, since the ease of liquid flow in the flow path is determined by the cross-sectional area of the flow path, the length of the flow path, etc., the cross-sectional areas and lengths of the inlet flow path 106a and the outlet flow path 106b should be set appropriately. For example, it is possible to make it easier for the liquid to flow out of the outlet channel 106b than the inlet channel 106a. For example, in this embodiment, the outlet channel 106b has a capillary shape with a diameter of about 1 mm and the inlet channel 106a has a diameter of about 0.3 mm. Therefore, the backflow from the inlet channel 106a is suppressed.

  In addition, in the inlet channel 106 a, there is a flow in which the liquid pressure-fed from the liquid supply means 300 tends to flow into the liquid chamber 110, which prevents the liquid from flowing out of the liquid chamber 110. In 106b, there are few elements which increase resistance and fluid inertia which prevent the outflow of the liquid in the liquid chamber 110. Therefore, the liquid pressurized in the liquid chamber 110 flows out of the outlet channel 106 b exclusively and is ejected from the nozzle 102 at the tip through the liquid ejection pipe 104.

  The interior of the liquid chamber 110 of this embodiment is partitioned in a spiral shape by the partition wall 120 w of the flow path forming member 120. However, when the volume of the liquid chamber 110 decreases due to the expansion of the piezoelectric element 112, the liquid does not flow along the spiral partition wall 120w (swirl channel), but the partition wall 120w is located on the outlet channel 106b side. The liquid in the liquid chamber 110 moves toward the outer peripheral side of the liquid chamber 110 by being deformed toward (the central portion of the liquid chamber 110). This point will be supplementarily described.

  First, considering as an example the partition wall 120w that forms the innermost wall of the spiral-shaped partition wall 120w that is wound in multiple layers, the inlet channel 106a is located in the center of the liquid chamber 110 inside the innermost partition wall 120w. Therefore, when the volume of the liquid chamber 110 decreases, an increase in pressure is suppressed by the liquid flowing out from the outlet channel 106b.

  On the other hand, the inlet channel 106a is a capillary inside the partition wall 120w, and the pressure rises compared to the outside of the partition wall 120w in order to suppress the outflow of fluid. Since the partition wall 120w is made of a flexible material so as to be deformable, the partition wall 120w is pushed and deformed from the high pressure inside to the low pressure outside, so that the pressure difference between the inside and the outside is increased. Try to decrease. In addition, since the partition wall 120w of a present Example is standingly arranged from the support plate 120b, and the front-end | tip is adhering to the recessed part bottom face 106d of the recessed part 106c of the 2nd case 106, it shows to Fig.10 (a). As described above, the central portion of the partition wall 120w is deformed so as to be bent from the inside by being pushed from the inside.

  The pressure difference between the inner side and the outer side of the partition wall 120w is not only the innermost partition wall 120w, but also the innermost partition wall 120w is deformed to the outside, and the inner pressure is lowered. It also occurs in the heavy partition wall 120w and similarly propagates to the triple partition wall 120w. Therefore, the spiral partition wall 120w is deformed so as to enlarge the spiral toward the outer peripheral side of the liquid chamber 110 as a whole.

  Thus, when the volume of the liquid chamber 110 decreases due to the expansion of the piezoelectric element 112, the central portion of the spiral partition wall 120 w is deformed so as to bend toward the outside of the liquid chamber 110, thereby As shown in FIG. 10B, the liquid moves from the center of the liquid chamber 110 toward the outlet channel 106b at the outer peripheral edge.

  Here, when the volume of the liquid chamber 110 decreases due to the expansion of the piezoelectric element 112, a corresponding amount of liquid is collected in the outlet channel 106 b and pushed out, so that the liquid is discharged from the nozzle 102 at the tip of the liquid ejection pipe 104. Be injected. At this time, it is considered that the spiral partition wall 120w in the liquid chamber 110 becomes an obstacle, and a sufficient amount of liquid cannot be collected from the periphery to the outlet channel 106b in the outer peripheral portion. However, in the pulsation generating unit 100 of the present embodiment, the displacement amount due to the expansion of the piezoelectric element 112 is small, and the amount of liquid ejected in one pulse (ejection amount) is relative to the volume of the liquid chamber 110. Since the partition wall 120w is slightly deformed toward the center of the liquid chamber 110, a sufficient amount of liquid is collected from the center portion in the outlet channel 106b. The technical logic for this is supported by the equations (1) to (4) described in the first embodiment.

  Further, as shown in FIG. 10A, the peripheral edge of the support plate 120b is fixed so as to be sandwiched between the first case 108 and the second case 106, and the outer diameter of the reinforcing plate 116 is the support plate 120b. Further, the cross-sectional dimension of the piezoelectric element 112 is smaller than the outer diameter of the reinforcing plate 116. Accordingly, when the liquid chamber 110 is pressed by the piezoelectric element 112, the outer peripheral edge is warped around the central portion where the inlet channel 106a is disposed, so that the pressing amount of the liquid chamber 110 is large in the vicinity of the central portion, and the volume is increased. The change is great. Further, the pressing amount is small on the outer peripheral side, and the change in volume is small. That is, it is considered that the pressure in the liquid chamber 110 is high in the central portion and low in the outer peripheral portion. Therefore, the liquid in the liquid chamber 110 is strongly pushed out from the central portion to the outer peripheral portion including that the liquid is fed from the liquid supply means 300 to the inlet channel 106a at a substantially constant pressure.

  Accordingly, the pressure in the vicinity of the inlet 110a in the center increases, and the return pressure of the liquid at the inlet 110a increases. However, since the diameter of the inlet 110a is small enough to be assumed to be a capillary, the backflow from the liquid chamber 110 to the inlet 110a is suppressed, so that the pressure of the liquid chamber 110 can be increased and strong liquid injection can be obtained. Can do.

  The liquid ejecting apparatus 10 according to the second embodiment described above includes a modification based on the same technical idea as the first and second modifications of the first embodiment described above.

  For example, a modified example having the same concept as the first modified example (see FIG. 6) described above can be used. That is, the tip of the partition wall 120w (the end facing the second case 106) is not fixed to the recess bottom surface 106d of the second case 106, and there is a slight gap between the tip of the partition wall 120w and the recess bottom surface 106d. This is a form in which a gap is provided. In the second embodiment, the inlet channel 106a is communicated with the central portion of the liquid chamber 110, and the outlet channel 106b is communicated with the outer peripheral end of the liquid chamber 110. The partition wall 120w is pushed and deformed. That is, the partition wall 120w is deformed in the outer peripheral direction opposite to the deformation direction shown in FIG.

  Therefore, in the pulsation generating unit 100, although the tip of the partition wall 120w is not fixed to the concave bottom surface 106d of the second case 106, the liquid flow in the liquid chamber 110 is filled when the liquid chamber 110 is filled with the liquid. Can be restricted to a constant flow along the spiral flow path formed by the partition wall 120w. Therefore, the bubbles do not stay in a place where the flow is slow, and the bubbles in the liquid chamber 110 can be quickly discharged.

  Further, when the piezoelectric element 112 expands and the volume of the liquid chamber 110 decreases, the tip of the partition wall 120w that is not fixed to the concave bottom surface 106d of the second case 106 falls down toward the outside of the liquid chamber 110. As a result, a liquid flow over the partition wall 120w and toward the outlet channel 106b at the outer peripheral edge is generated inside the liquid chamber 110. As described above, the liquid is collected in the outlet channel 106b by the flow crossing the spiral channel, so that the liquid can be strongly ejected.

  Further, a modified example having the same concept as the above-described second modified example (see FIG. 7) can be used. That is, the partition wall 120w is not fixed to the recess bottom surface 106d of the second case 106, and a slight gap is provided between the partition wall 120w and the recess 106c. In addition, the entire partition wall 120w is not erected from the support plate 120b, but only the outermost portion of the spiral-shaped partition wall 120w wound in multiple layers is erected on the support plate 120b. (Refer FIG. 7) The remaining part is a series in a spiral shape, but is not fixed to the support plate 120b.

  Also in the pulsation generating unit 100 to which the second modification example is applied, when the liquid chamber 110 is filled with the liquid, the liquid flow in the liquid chamber 110 is separated from the partition wall as in the above-described embodiment. Since the flow is restricted to a constant flow along the spiral flow path formed by 120w, it is possible to quickly discharge the bubbles in the liquid chamber 110 on the flow.

  On the other hand, when the volume of the liquid chamber 110 decreases due to the expansion of the piezoelectric element 112 and a pressure difference is generated between the inside and the outside of the partition wall 120w as described above, the partition is performed from the high pressure inside to the low pressure outside. The wall 120w is pushed. At this time, the pressurized liquid in the liquid chamber 110 moves toward the outside of the liquid chamber 110. In addition, the liquid flows toward the outlet channel 106b at the outer peripheral edge so as to cross the spiral channel and cross the partition wall 120w, and the liquid is collected in the outlet channel 106b, so that the liquid is strongly ejected. be able to.

  The liquid ejecting apparatus 10 described above is a surgical instrument for incising or excising a living tissue by spraying a liquid such as water or physiological saline toward the living tissue, or applying a chemical solution to a wound or washing. In addition to medical use, the present invention can be utilized as a device that uses a small amount of liquid to be ejected at high speed, such as drawing using ink as a liquid, cleaning of precision parts, and a cooling device for electronic equipment.

  DESCRIPTION OF SYMBOLS 10 ... Liquid injection apparatus, 100 ... Pulsation generation | occurrence | production part, 102 ... Nozzle, 106a ... Inlet flow path, 106b ... Outlet flow path, 110 ... Liquid chamber, 112 ... Piezoelectric element, 120 ... Channel formation member, 120b ... Support plate, 120w ... partition wall, 200 ... control unit, 300 ... liquid supply means.

Claims (8)

A liquid ejecting apparatus that ejects liquid from a nozzle,
An inlet channel through which the liquid is supplied;
An outlet channel communicating with the nozzle;
A liquid chamber having a given volume partitioned in a spiral shape by a deformable partition wall between the inlet channel and the outlet channel;
A volume changing unit that deforms the liquid chamber toward a first direction in which the volume of the liquid chamber is decreased from the given volume;
In a state where the liquid is filled in the liquid chamber, by driving the volume changing unit, the ejection control means for ejecting the liquid in pulses from the nozzle;
A liquid ejecting apparatus comprising: The volume changing unit has a piezoelectric element,
Reducing the volume of the liquid chamber by stretching the piezoelectric element; and
The piezoelectric element is disposed so as to press the liquid chamber in a state where the piezoelectric element is not expanded;
The liquid ejecting apparatus according to claim 1. The sectional area of the inlet channel is smaller than the sectional area of the outlet channel, and the inlet channel is a capillary;
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. The partition wall forming the liquid chamber is erected from either one of the surface on the first direction side constituting the liquid chamber or the surface on the second direction side facing the surface on the first direction side. And that the tip is not fixed,
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. The partition wall forming the liquid chamber is erected from either one of the surface on the first direction side constituting the liquid chamber or the surface on the second direction side facing the surface on the first direction side. And the tip is provided in a state fixed to the other surface facing the one surface,
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. The flow path of the liquid chamber has a substantially uniform cross-sectional area;
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. The inlet channel communicates with the outer peripheral edge of the liquid chamber;
The outlet channel is in communication with a central portion of the liquid chamber;
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. The inlet channel communicates with a central portion of the liquid chamber;
The outlet channel is in communication with an outer peripheral edge of the liquid chamber;
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus.

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