JP2009236179A - Flow passage regulation member and liquid discharge device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow passage regulation member which can be used for a relatively long period of time while exhibiting a stable performance. <P>SOLUTION: The flow passage regulation member is provided with a cylinder body having an inner space and a through-hole communicating with the inner space, a shaft member inserted into the inner space and provided with a flow passage communicable with the through-hole. In the flow passage regulation member, a communicating state of the through-hole and the flow passage changes as the shaft member is rotated around a shaft direction and a route of a fluid flowing from the through-hole to the inner space side is regulated in accordance with the communicating state. In a clearance between an inner circumferential surface of the cylinder body and an outer circumferential surface of the shaft member, a side of an end part of a longitudinal direction of the shaft member is larger than that at a center position in the longitudinal direction of the shaft member. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flow path defining member used for switching a fluid path and a liquid ejection apparatus using the same.

  Conventionally, liquid metering devices and pump devices have been widely used in various fields such as a resist coating process in a semiconductor manufacturing process or the like, and a liquid crystal dropping process in a liquid crystal manufacturing process.

  In recent years, with the progress of miniaturization of semiconductor elements and liquid crystal elements, it is required to control the contamination in the liquid coating process to a smaller extent. There is also a need for a device that can withstand long-term use, that is, a device with relatively high durability.

For example, Patent Document 1 described below describes a liquid ejection device that includes a metal valve made of stainless steel.
JP 2006-275133 A

  However, a metal valve made of stainless steel or the like has a relatively low wear resistance, and a metal component generated from the valve may be mixed into the liquid to be discharged as contamination. Further, the discharge amount of the liquid may change due to wear, and the life as a liquid discharge device is relatively short.

  In view of the above problems, the present invention includes a cylindrical body having an internal space and provided with a through hole communicating with the internal space, and a flow path inserted into the internal space and capable of communicating with the through hole. A shaft member, and the shaft member is rotated about the axial direction to change the communication state between the through hole and the flow path, and flows into the inner space from the through hole. The fluid path is a flow path defining member defined according to the communication state, and a gap between the inner peripheral surface of the cylindrical body and the outer peripheral surface of the shaft member is in the length direction of the shaft member. The flow path defining member is characterized in that the end portion side is larger than the center position in the length direction of the shaft member.

  In addition, it is preferable that the said space | interval in the center position of the length direction of the said shaft member is 6 micrometers or less.

  Moreover, it is preferable that the said shaft member and the said cylindrical body have zirconia as a main component.

  Moreover, it is preferable that the outer peripheral surface of the shaft member has a grinding streak continuous along the circumferential direction.

  Moreover, it is preferable that the average length RSm of the contour curve element prescribed | regulated to JIS B0601-2001 along the length direction of the said shaft member of the outer peripheral surface of the said shaft member is 0.005-0.008 mm. .

  Moreover, it is preferable that the outer peripheral surface of the shaft member has a zirconia monoclinic crystal ratio of 5 mol% or less.

Further, it is preferable that the ratio of the _Y 2 _{O 3} contained in the shaft member and the cylindrical body is not less than 2 mol% and less 6 mol%.

  The present invention also provides the above-described flow path defining member, a liquid supply unit that supplies liquid from the through hole toward the internal space, and the liquid that has flowed through the flow path defined by the flow path defining member. And a liquid discharge device characterized by comprising a discharge unit for discharging the liquid.

  Since the flow path defining member of the present invention has a relatively high wear resistance, the contamination mixed into the liquid is relatively small, and can be used with a stable performance for a relatively long time. Further, the rotational resistance of the shaft member is relatively small, and the amount of liquid leakage from the gap between the shaft member and the outer member is relatively small.

  Hereinafter, the best mode for carrying out the present invention will be described.

  FIG. 1 is a schematic cross-sectional view illustrating a flow path switching valve 10 which is an embodiment of a flow path defining member of the present invention. The flow path switching valve 10 in FIG. 1 is provided in the liquid supply apparatus 1. The liquid supply apparatus 1 includes a first liquid supply unit 2, a second liquid supply unit 4, a discharge nozzle 6, and a flow path switching valve 10. Each means is connected to each other via a liquid supply path such as a pipe (not shown). The first liquid supply means 2 includes a chemical liquid tank and a pressure supply mechanism (not shown), and supplies the first chemical liquid to the flow path switching valve 10. Similarly, the second liquid supply means 4 also includes a chemical liquid tank and a pressure supply mechanism (not shown), and supplies the second chemical liquid to the flow path switching valve 10.

  The flow path switching valve 10 is inserted into a substantially cylindrical frame 20. The frame body 20 is provided with a plurality of chemical solution flow holes (first flow holes 22a, second flow holes 22b, and third flow holes 22c). Each chemical solution flow hole (first flow hole 22a, second flow hole 22b, and third flow hole 22c) is provided with a flow path connector. Each chemical fluid circulation hole is connected to the first liquid supply means 2, the second liquid supply means 4, and the discharge nozzle 6 via a liquid supply path such as a pipe.

  The flow path switching valve 10 includes a substantially cylindrical outer member 12 having a plurality of through holes (a first inflow hole 16a, a second inflow hole 16b, a first outflow hole 18a, and a second outflow hole 18b) on a side surface, And a shaft member 14 inserted into an internal space surrounded by the outer shell member 12.

  FIG. 2 is a schematic perspective view of the shaft member. The shaft member 14 includes two through holes 14 a and 14 b provided so as to pass through the central axis of the shaft member 14 and extending in directions orthogonal to each other. In the flow path switching valve 10, the shaft member 14 is switched between the first state and the second state by rotating about the axial direction. In the first state, as shown by a solid line in FIG. 1, the first flow hole 22a, the first inflow hole 16a, the through hole 14a, and the first outflow hole 18a are in communication with each other. In the first state, the first chemical liquid supplied from the first flow hole 22a is sent to the discharge nozzle 6 through the third flow hole 22c. In the second state, as shown by a broken line in FIG. 1, the second flow hole 22b, the second inflow hole 16b, the through hole 14b, and the second outflow hole 18b are in communication with each other. In this second state, the second chemical liquid supplied from the second flow hole 22b passes through the above-described path, the outflow path 23 provided on the inner surface of the frame 20, and the third outflow hole 22c. To the discharge nozzle 6. In the liquid supply apparatus 1, the kind of the chemical liquid discharged from the discharge nozzle 6 is changed between the first chemical liquid and the second chemical liquid by switching the flow path switching valve 10 between the first state and the second state. It can be switched with chemicals.

  In the flow path switching valve 10, both the shaft member 14 and the outer member 12 are formed of zirconia. Zirconia has a relatively high wear resistance, and the degree of wear when the two members slide between the outer peripheral surface of the shaft member 14 and the inner peripheral surface of the outer shell member 12 is relatively small. At least one of the shaft member and the outer member only needs to be made of a material mainly composed of zirconia. “Containing zirconia as a main component” means, for example, that it contains 60% by mass or more of zirconia.

  FIG. 3 is a cross-sectional view showing an outline of the flow path switching bubble 10. In FIG. 3, the shape of the shaft member 14, particularly the change in diameter around the rotation axis, is exaggerated. In the flow path switching valve 10, the clearance (clearance) between the inner peripheral surface of the outer member 12 and the outer peripheral surface of the shaft member 14 is larger than the clearance B at the end in the length direction of the outer member 12. The clearance A at the center in the length direction is made smaller. For example, the clearance B is 5 μm, and the clearance A is 3 μm.

  The larger the gap between the inner peripheral surface of the outer member 12 and the outer peripheral surface of the shaft member 14, the smaller the rotational resistance of the shaft member 14. That is, it can be smoothly rotated with a relatively small force. Further, the smaller the gap between the inner peripheral surface of the outer shell member 12 and the outer peripheral surface of the shaft member 14, the higher the sealing performance of the target liquid for switching the flow path. In other words, the narrower the gap, the smaller the amount of chemical liquid that leaks from the gap.

  In the flow path switching valve 10 of the present embodiment, the clearance A in the central portion is made relatively small, the sealing performance of the chemical solution is made sufficiently high, and the clearance B in the vicinity of the end in the length direction is made relatively large so that the shaft The resistance (rotational resistance) when rotating the member 14 is relatively small.

  In order to improve the sealing performance of the chemical solution and reduce the amount of chemical solution leaked from the gap between the shaft body 14 and the outer member 12, the clearance A at the central portion is preferably 6 μm or less. . According to the flow path switching valve of the present invention, the shaft 14 and the outer member made of zirconia can be used without using a sealing mechanism for sealing liquid (a sealing tape for preventing leakage or a resin material for preventing leakage). The flow path switching mechanism with a relatively small leakage of the chemical solution can be configured with only the two members.

  The shaft member 14 of the present embodiment is formed by grinding the outer peripheral surface by so-called cylindrical outer surface honing, which is performed by rotating the shaft member 14 around the central axis and bringing the grinding member into contact with the outer peripheral surface. ing. A general ceramic material has a relatively small fracture toughness value compared to, for example, a metal or the like, but zirconia has a relatively large fracture toughness value among the ceramics. For this reason, when zirconia is ground, there are relatively few surface defects (voids and the like) after grinding, and the surface tends to be a mirror surface. On the other hand, since zirconia has a relatively large fracture toughness value among ceramics, it tends to cause plastic flow type grinding marks on the ground surface. That is, on the outer peripheral surface of the shaft member 14 formed by grinding, relatively long and fine concave portions and convex portions exist along the circumferential direction of the shaft member 14.

  Further, in the flow path switching valve 10 of the present embodiment, the inner peripheral surface of the outer member 12 is also formed by so-called honing inner peripheral processing. Also on this inner peripheral surface, a grinding trace extending relatively long along the circumferential direction is generated.

  FIG. 4 is a schematic cross-sectional view illustrating the flow path switching valve 10 and shows the vicinity of the central portion of the outer member 12 in the length direction in an enlarged manner. In the flow path switching valve 10 of the present embodiment, ground marks are formed on the outer peripheral surface of the shaft member 14 and the inner peripheral surface of the outer member 12, respectively. For this reason, even if the force that the outer peripheral surface of the shaft member 14 and the inner peripheral surface of the outer shell member 12 approach is applied, the convex portion of the grinding trace first comes into contact with the entire concave portion of the grinding trace. There is no. Therefore, when viewed microscopically, an appropriate clearance is maintained between the outer peripheral surface of the shaft member 14 and the inner peripheral surface of the outer member 12, and the rotational resistance of the shaft member 14 is kept relatively low. . In addition, since grinding marks are formed on the outer peripheral surface of the shaft member 14 and the inner peripheral surface of the outer member 12, respectively, the surface area of the outer peripheral surface of the shaft member 14 and the surface area of the inner peripheral surface of the outer member 12 Are relatively large. That is, in the gap (clearance) between the shaft member 14 and the outer member 12, the surface area with which the chemical solution contacts is relatively large compared to the distance between the shaft member 14 and the outer member 12. For this reason, the surface tension generated in the chemical liquid entering the gap is relatively large, and the leakage of the chemical liquid from the gap is relatively small.

  If the average length RSm of the contour curve element on the outer peripheral surface of the shaft member 14 is set to 0.005 mm or more, the liquid sealing property can be made relatively high. Further, if the average length RSm of the contour curve element on the outer peripheral surface of the shaft member 14 is set to 0.008 mm or less, the amount of contamination caused by the contact between the outer member 12 and the shaft member 14 is relatively reduced. be able to. In this case, the amount of contamination mixed into the chemical liquid discharged from the discharge nozzle 6 can be relatively reduced.

  Here, the average length (RSm) of the contour curve element is a value based on JIS B0601-2001. For the measurement of the average length (RSm) of the contour curve element, for example, using Kosaka Laboratory Co., Ltd. surface roughness measuring device Surfcorder SE-2300, the cut-off value is 0.08 mm with a reference length of 0.4 mm. And it is sufficient. In addition, the average length (RSm) of the contour curve element may be a value based on JIS B0601-2001, and may not be a value using the measuring device.

  Note that whether or not grinding-shaped marks are formed on the outer peripheral surface of the shaft member and the inner peripheral surface of the outer shell member depends on whether the average length (RSm) of the contour curve element is less than 0.004 mm. Judgment can be made.

  FIG. 5 is a diagram for explaining the average length (RSm) of the contour curve elements. The average length (RSm) of the contour curve element represents the average of the contour curve elements Xs at the reference length. Only the reference length is extracted from the surface roughness curve in the direction of the average line, and the sum of the pair of adjacent peaks and valleys in the extracted portion in the horizontal direction is obtained, and the arithmetic average value is expressed in millimeters. In the present embodiment, the average length (RSm) of the contour curve element is a value obtained from the contour line along the length direction of the outer member 12 (the length direction of the shaft member 14).

  Moreover, in the flow path switching valve 10 of this embodiment, the monoclinic crystal ratio of the outer peripheral surface of the shaft member 14 is 5 mol% or less. The monoclinic crystal ratio can be calculated by analyzing the crystal structure by X-ray diffraction of the outer peripheral surface of the shaft member 14. For the analysis of the crystal structure by X-ray diffraction, for example, PW3050 manufactured by Spectris Co., Ltd. may be used, and measurement may be performed at 50 mA with an X-ray output of 40 Kv in the range of 2Θ = 26 ° to 36 °.

  For example, zirconia is known to undergo a phase transformation of the surface crystal phase due to processing stress. For example, a tetragonal crystal undergoes a phase transformation due to stress and changes to a monoclinic crystal, but this causes volume expansion, and a deteriorated layer may be formed on the surface. Or a fracture alteration layer may be formed by processing. On the surface on which the fracture-affected layer is formed by processing, the zirconia crystals on the surface are relatively easy to degranulate.

  If the monoclinic crystal ratio of the outer peripheral surface of the shaft member 14 is 5 mol% or less, the fracture-affected layer on the outer peripheral surface can be kept relatively low. By setting the monoclinic crystal ratio of the outer peripheral surface of the shaft member to 5 mol% or less, it is possible to relatively reduce the degranulation of zirconia crystals on the surface. If the monoclinic crystal ratio of the outer peripheral surface of the shaft member is 5 mol% or less, the contamination mixed into the flow path flowing through the flow path switching member can be kept relatively low.

In the flow path switching valve 10, both the outer shell member 12 and the shaft member 14 are partially stabilized zirconia using Y ₂ O ₃ as a sintering aid. Further, both the outer member 12 and the shaft member 14 have a Y ₂ O ₃ content in the range of ₂ to 6 mol%. When the content of Y ₂ O ₃ is in the range of ₂ to 6 mol%, it is difficult for phase transformation from tetragonal to monoclinic, and the sliding contact surface can exhibit relatively high wear resistance and corrosion resistance. The flow path switching valve 10 made of zirconia containing Y ₂ O ₃ has relatively high wear resistance, and the amount of contamination mixed into the chemical solution is also relatively small. In order to further increase the wear resistance and corrosion resistance, it is more preferable to set the content of Y ₂ O ₃ in the range of ₂ to 4 mol%.

  FIG. 6 is a schematic diagram for explaining another embodiment (second embodiment) of the flow path defining component of the present invention. The pump member 60 shown in FIG. 6 includes a fixed valve body 66, a first movable valve body 67a, and a second movable valve body 67b, and the movable valve bodies 67a and 67b reciprocate separately, so that a substantially constant amount is obtained. Liquid from the inlet port 68 to the outlet port 69. Specifically, first, as shown in FIG. 6 (a), from the state where the entrance port 68 is positioned in the gap between the movable valve body 67a and the movable valve body 67b, it is movable as shown in FIG. 6 (b). The valve body 67b moves, and the capacity of the gap between the movable valve body 67a and the movable valve body 67b is set to a predetermined size. In the state shown in FIG. 6B, a predetermined volume of fluid flows from the flow path port 68 and accumulates in the gap between the movable valve body 67a and the movable valve body 67b. Next, as shown in FIG. 6 (c), the movable valve body 67a and the movable valve body 67b are movable until the gap reaches a position corresponding to the output port 69 in a state where the size of the gap is maintained. The valve body 67a and the movable valve body 67b move integrally. Next, as shown in FIG. 6 (d), the movable valve body 67 a moves to reduce the capacity of the gap between the movable valve body 67 a and the movable valve body 67 b, and the fluid in this gap flows from the flow path port 69. Leaked.

  FIG. 7 is a schematic view for explaining another embodiment (third embodiment) of the flow path defining member according to the present invention. In the flow path defining member 70 shown in FIG. 7, a shaft 74 having a cut portion 74a provided at one end thereof is inserted into the internal space of the cylindrical outer member 72 whose one end is closed. Has been placed. In the flow path defining member 70, as shown in FIGS. 7A to 7E, the shaft body 74 rotates inside the outer member 72 while reciprocating along the length direction of the shaft body 74. In the flow path defining member 70, the fluid that has flowed in from the inflow hole 72 a provided on the side surface on one side of the outer member 72 by the reciprocating / rotating motion of the cut portion 74 a accompanying the reciprocating / rotating motion of the shaft body 74. Flows out from an outflow hole 72b provided on the other side surface of the outer shell member 72. In the flow path defining member 70, the amount of fluid flowing out from the inflow hole 72a and out of the outflow hole 72b while the shaft body 74 is reciprocated (and rotated once) is reduced between the cut portion 74a and the outer member 72. The size is defined to correspond to the space surrounded by the inner peripheral surface. The shape and configuration of the flow path defining member of the present invention are not particularly limited.

The flow path defining member made of zirconia can be manufactured, for example, by the following method. For example, zirconia powder is molded by a molding method such as CIP at a molding pressure of 0.8 to 1.5 ton / cm ² , cut into a desired shape, and then fired at 1350 to 1600 ° C. What is necessary is just to grind to the shape. At this time, by performing so-called honing, the clearance between the shaft member and the outer member can be made wider at the end portion than at the central portion. Further, by performing HIP (hot part hydraulic forming) after sintering, voids generated on the surface can be made relatively small, and the strength and hardness can be made relatively high.

  In addition, you may finish by ELID grinding, tape grinding | polishing etc. as finishing as needed. For example, a grinding process may be performed by applying a voltage in a range of 20 to 90% of 60V or 90V with a cast iron bond. Further, for example, polishing may be performed with a tape containing abrasive grains.

  In the grinding of ceramics, for example, a grinding member such as diamond abrasive grains hits the ceramics to generate a crack due to the contact stress, and as the abrasive grains pass, the machining progresses by digging up as chips. The microscopic destruction of the processed surface that occurs at this time depends on the magnitude of the stress. By controlling the grinding conditions, the surface shape of the sliding contact surface and the ratio of the monoclinic crystal ratio can be controlled.

  Experiment 1: Using the flow path defining member having the configuration shown in FIG. 1, the chemical solution from the gap between the shaft member and the outer member when the first chemical solution was continuously flowed from the first flow hole to the third flow hole Both the presence / absence of leakage and the presence / absence of contamination contained in the chemical discharged from the discharge nozzle were confirmed.

  As the flow path defining member, the outer member has an axial length: about 20 mm, an inner diameter: about 5 mm, and an outer diameter: about 10 mm. The shaft member had an outer diameter of about 5 mm and an axial length of about 25 mm. As an experimental example, a plurality of experimental sample Nos. 1 and 2 in which the size of RSm on the outer surface of the shaft member and the clearance between the outer member and the shaft member (clearance at the central portion in the axial direction) are different. 1-No. 10 was prepared, and each experimental example sample No. 1-No. For each of the ten samples, the presence or absence of occurrence of chemical leakage and the presence or absence of contamination contained in the discharged chemical were investigated.

  At this time, a liquid having a viscosity of 2000 pps is used as the chemical liquid, and this liquid is pressurized to a liquid pressure of 100 kPa by the pump device as the first liquid supply means and supplied to the flow path defining member. And let it pass. Table 1 below shows the results of the presence or absence of occurrence of chemical leakage and the presence or absence of contamination contained in the discharged chemical when each experimental example sample is used.

  Here, the occurrence of chemical leakage means that the amount of leakage per 30 minutes is 0.25 g or more. Further, “contamination is included” means that there is one or more contamination of 1 μm or more.

  As can be seen from Table 1, no contamination occurred in any of the experimental samples whose RSm was 0.08 mm or less. Moreover, in the experimental sample with RSm of 0.005 to 0.015 mm, no chemical leakage occurs. Further, when the RSm is 0.005 mm to 0.008 mm, both the occurrence of contamination and the leakage of the chemical solution can be suppressed.

Experiment 2;
About the some experimental sample measured on the conditions similar to the said Experimental example 1, the leakage amount of the chemical | medical solution was measured. In this Experimental Example 2, a plurality of Experimental Sample Nos. With different clearance sizes between the shaft body and the outer member. About 11-14, the liquid with a viscosity of 2000 pps is used as a chemical | medical solution, this liquid is pressurized to the liquid pressure of 100 kPa with the pump apparatus which is a 1st liquid supply means, is supplied to a flow-path definition member, and a flow-path prescription | regulation member is supplied for 12 hours. Passed continuously. Table 2 below shows the clearance size of each experimental sample and the amount of chemical leakage when each sample is used. In addition, about each experimental sample, the leakage amount of the chemical | medical solution was measured repeatedly 3 times. The numerical value of the amount of leaking chemical solution shown in Table 2 is a value obtained by averaging three measured values of the leakage amount. Further, in FIG. 8, the result of this experimental example 2 shown in Table 2 is shown as a graph.

  As can be seen from the graphs shown in Table 2 and FIG. 8, when the clearance is 6 μm or less, it is found that the amount of leakage of the chemical solution from the flow path defining member can be suppressed to a relatively small value.

  The flow path defining member and the droplet discharge device of the present invention have been described above. However, the flow path defining member and the droplet discharge device of the present invention are not limited to the above-described embodiments, and depart from the gist of the present invention. Of course, various improvements and modifications may be made without departing from the scope.

It is the schematic explaining one Embodiment of the liquid discharge apparatus of this invention comprised including one Embodiment of the flow-path definition member of this invention. It is a schematic perspective view of one Embodiment of the shaft member with which the flow-path definition member of this invention is provided. It is a schematic sectional drawing of one Embodiment of the flow-path definition member of this invention. It is the schematic explaining the flow-path definition member of this invention, and is a figure which expands and shows the center part vicinity of an outer shell member. It is a figure explaining average length (RSm) of a contour curve element. (A)-(d) is the schematic explaining other embodiment of the flow-path definition component of this invention. (A)-(e) is the schematic explaining other embodiment of the flow-path definition component of this invention. It is a graph which shows an example of the result of the experiment example performed using the some sample containing an example of the flow-path definition member of this invention, and shows the chemical | medical solution leak amount for every sample.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid supply apparatus 2 1st liquid supply means 4 2nd liquid supply means 6 Discharge nozzle 10 Flow path switching valve 12 Outer member 14 Shaft member 16a 1st inflow hole 16b 2nd inflow hole 18a 1st outflow hole 18b 2nd outflow hole 20 Frame body 22a 1st flow hole 22b 2nd flow hole 22c 3rd flow hole 23 Outflow path 60 Pump member 66 Fixed valve body 67a 1st movable valve body 67b 2nd movable valve body 68 Inlet port 69 Outlet port

Claims (8)

A cylindrical body having an internal space and having a through hole communicating with the internal space;
A shaft member that is inserted into the internal space and has a flow path that can communicate with the through hole;
The communication state between the through hole and the flow path is changed by rotating the shaft member about the axial direction, and the path of the fluid flowing from the through hole toward the inner space is the communication state. A flow path defining member defined according to
The gap between the inner peripheral surface of the cylindrical body and the outer peripheral surface of the shaft member is such that the end side in the length direction of the shaft member is larger than the center position in the length direction of the shaft member. A flow path defining member.   2. The flow path defining member according to claim 1, wherein the interval at a central position in the length direction of the shaft member is 6 μm or less.   The flow path defining member according to claim 1, wherein the shaft member and the cylindrical body are mainly composed of zirconia.   The flow path defining member according to claim 3, further comprising a grinding streak continuous along a circumferential direction on an outer peripheral surface of the shaft member.   The average length RSm of the contour curve element defined in JIS B0601-2001 along the length direction of the shaft member on the outer peripheral surface of the shaft member is 0.005 to 0.008 mm. The flow path defining member according to claim 3 or 4.   6. The flow path defining member according to claim 3, wherein a ratio of monoclinic zirconia is 5 mol% or less on the outer peripheral surface of the shaft member. The flow path regulating member according to claim _{3, wherein} a ratio of Y ₂ O ₃ contained in the shaft member and the cylindrical body is 2 mol% or more and 6 mol% or less. A flow path defining member according to any one of claims 1 to 7,
A liquid supply section for supplying liquid from the through hole toward the internal space;
A discharge section for discharging the liquid flowing through the flow path defined by the flow path defining member;
A liquid ejection apparatus comprising:

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