Positive pressure adjustment mechanism and liquid discharge device

Abstract

To provide a positive pressure adjustment mechanism that can reduce leakage of liquid, while reducing friction resistance, and a liquid discharge device.SOLUTION: A positive pressure adjustment mechanism comprises: a supply chamber 54; a pressure chamber 55 having a first flexible part 63 and provided downstream of the supply chamber 54; a first communication path 57 communicating the supply chamber 54 with the pressure chamber 55; a second communication path 58 which is provided concentrically with the first communication path 57 and communicates the supply chamber 54 with the pressure chamber 55; an opening / closing part 59 that has a first shaft part 66 which moves following displacement of the first flexible part 63 and a first valve part 67 which is connected to the first shaft part 66 and can open and close the first communication path 57; a first sealing part 60 that performs sealing between an outer periphery of the first shaft part 66 and an inner periphery of the second communication path 58; and a pressurizing part 56 that pressurizes the first flexible part 63 in a first direction D1. The first sealing part 60 has a first arm part 60a that approaches the outer periphery of the first shaft part 66 as going toward the first direction D1, and a second arm part 60b that approaches the inner periphery of the second communication path 58 as going toward the first direction D1.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a positive pressure adjustment mechanism and a liquid ejection device. [Background technology]

[0002] For example, Patent Document 1 discloses a pressure reducing valve which is an example of a positive pressure adjustment mechanism. The pressure reducing valve includes a valve body, a valve element which is an example of an opening / closing portion, and a seal member which is an example of a first seal portion. The valve body has a primary pressure chamber which is an example of a supply chamber, a secondary pressure chamber which is an example of a pressure chamber, a first sliding hole which is an example of a second communication passage, and a valve hole which is an example of a first communication passage. The first sliding hole and the valve hole have the same axis. The valve element is inserted into the first sliding hole and the valve hole, and opens and closes the valve hole. The seal member closes the gap between the first sliding hole and the valve body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-149223 Summary of the Invention [Problem to be solved by the invention]

[0004] The seal member in Patent Document 1 is a so-called O-ring with a circular cross section. The O-ring closes the gap between the first sliding hole and the valve body by being crushed. When the O-ring is crushed to a greater extent, the degree of sealing is improved and leakage is reduced. However, when the O-ring is crushed, frictional resistance increases, making it difficult to move the valve body. [Means for solving the problem]

[0005] a first communication passage connecting the supply chamber and the pressure chamber; a second communication passage connected coaxially with the first communication passage and connecting the supply chamber and the pressure chamber; an axis portion inserted into the first communication passage and moving in response to displacement of the flexible portion; and a valve portion connected to the axis portion and capable of opening and closing the first communication passage; a first seal portion sealing between an outer periphery of the axis portion and an inner periphery of the second communication passage; and a pressurizing portion pressurizing the flexible portion in a first direction in which the volume of the pressure chamber decreases, wherein the first seal portion has a first arm portion approaching the outer periphery of the axis portion as it moves in the first direction, and a second arm portion approaching the inner periphery of the second communication passage as it moves in the first direction.

[0006] A positive pressure adjustment mechanism that solves the above problem comprises a supply chamber having an inlet through which liquid flows in, a pressure chamber having a flexible portion formed of a flexible member, located downstream of the supply chamber and having an outlet through which the liquid flows out, a first communication passage connecting the supply chamber and the pressure chamber, a second communication passage located coaxially with the first communication passage and connecting the supply chamber and the pressure chamber, an opening / closing portion having an axis portion inserted into the first communication passage and the second communication passage and moving in response to displacement of the flexible portion, and a valve portion connected to the axis portion and capable of opening and closing the first communication passage, a first seal portion provided on the outer periphery of the axis portion and sealing between the inner periphery of the second communication passage, and a pressurizing portion that pressurizes the flexible portion in a first direction in which the volume of the pressure chamber decreases, and the first seal portion has an arm portion that approaches the inner periphery of the second communication passage as it moves in the first direction.

[0007] A positive pressure adjustment mechanism that solves the above problem comprises a supply chamber having an inlet through which liquid flows in, a pressure chamber having a flexible portion formed of a flexible member, located downstream of the supply chamber and having an outlet through which the liquid flows out, a first communication passage connecting the supply chamber and the pressure chamber, a second communication passage located coaxially with the first communication passage and connecting the supply chamber and the pressure chamber, an opening / closing unit having a shaft portion inserted into the first communication passage and the second communication passage and moving in response to displacement of the flexible portion, and a valve portion connected to the shaft portion and capable of opening and closing the first communication passage, a first seal portion located on the inner circumference of the second communication passage and sealing between the outer circumference of the shaft portion, and a pressurizing unit that pressurizes the flexible portion in a first direction in which the volume of the pressure chamber decreases, and the first seal portion has an arm portion that approaches the outer circumference of the shaft portion as it moves in the first direction.

[0008] A liquid ejection device that solves the above problem includes a liquid ejection head capable of ejecting the liquid, a positive pressure flow path for supplying the liquid to the liquid ejection head, and a positive pressure adjustment mechanism of the above configuration that is provided in the positive pressure flow path.

[0009] A liquid ejection device that solves the above problem includes a liquid ejection head capable of ejecting the liquid, a positive pressure flow path for supplying the liquid to the liquid ejection head, a negative pressure flow path for recovering the liquid from the liquid ejection head, a positive pressure adjustment mechanism of the above configuration provided in the positive pressure flow path, and a negative pressure adjustment mechanism provided in the negative pressure flow path for adjusting the negative pressure on the liquid ejection head side. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of an embodiment of a liquid ejection device. [Diagram 2] FIG. 2 is a schematic diagram of a positive pressure adjustment mechanism included in the liquid ejection device. [Diagram 3] FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. [Figure 4] FIG. 4 is a schematic diagram of a negative pressure adjustment mechanism included in the liquid ejection device. [Diagram 5]FIG. 5 is a schematic diagram of a first modified example of the positive pressure adjustment mechanism. [Figure 6] FIG. 6 is a schematic diagram of a second modified example of the positive pressure adjustment mechanism. [Figure 7] FIG. 7 is a schematic diagram of a fourth modified example of the positive pressure adjustment mechanism. [Figure 8] FIG. 8 is a schematic diagram of a fifth modified example of the liquid ejection device. [Figure 9] FIG. 9 is a schematic diagram of a sixth modified example of the liquid ejection device. [Figure 10] FIG. 10 is a schematic diagram of a seventh modified example of the liquid ejection device. [Figure 11] FIG. 11 is a schematic diagram of an eighth modified example of the liquid ejection device. [Figure 12] FIG. 12 is a schematic diagram of a ninth modification of the liquid ejection device. [Figure 13] FIG. 13 is a schematic diagram of a tenth modified example of the liquid ejection device. [Figure 14] FIG. 14 is a schematic diagram of an eleventh modified example of the liquid ejection device. [Figure 15] FIG. 15 is a schematic diagram of a twelfth modification of the liquid ejection device. [Figure 16] FIG. 16 is a schematic diagram of a thirteenth modified example of the liquid ejection device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [Embodiment] Hereinafter, an embodiment of a positive pressure adjustment mechanism and a liquid ejection device will be described with reference to the drawings. The liquid ejection device is, for example, an inkjet printer that ejects ink, which is an example of a liquid, onto a medium such as paper, fabric, vinyl, plastic parts, or metal parts to print.

[0012] <Liquid discharge device> As shown in Fig. 1, a liquid ejection device 11 includes a liquid ejection head 12. The liquid ejection head 12 is capable of ejecting liquid. The liquid ejection head 12 is configured to eject liquid onto a medium M1. The liquid ejection head 12 has a nozzle surface 14 in which one or more nozzles 13 open. The liquid ejection head 12 ejects liquid from the nozzles 13.

[0013] The liquid ejection head 12 is formed with an introduction path 15, a common liquid chamber 16, and one or more individual liquid chambers 17. The introduction path 15, the common liquid chamber 16, and the one or more individual liquid chambers 17 are spaces within the liquid ejection head 12. Liquid flows through the introduction path 15, the common liquid chamber 16, and the one or more individual liquid chambers 17.

[0014] The introduction path 15 is a space for introducing liquid into the liquid ejection head 12. The common liquid chamber 16 communicates with the introduction path 15. Liquid is introduced into the common liquid chamber 16 through the introduction path 15. One or more individual liquid chambers 17 communicate with the common liquid chamber 16. Liquid is introduced into one or more individual liquid chambers 17 through the common liquid chamber 16. When multiple individual liquid chambers 17 are formed in the liquid ejection head 12, the multiple individual liquid chambers 17 communicate with the common liquid chamber 16. One individual liquid chamber 17 communicates with one nozzle 13. Therefore, the liquid ejection head 12 has the same number of individual liquid chambers 17 as the nozzles 13. The liquid ejection head 12 ejects liquid from the nozzles 13 by applying pressure to the liquid located in the individual liquid chambers 17.

[0015] The liquid ejection head 12 may have a filter 18. In one example, the filter 18 is located in the introduction path 15. More specifically, the filter 18 is located at an end of the introduction path 15 that is connected to the common liquid chamber 16. The filter 18 collects air bubbles, foreign matter, and the like contained in the liquid. As a result, the liquid from which air bubbles, foreign matter, and the like have been removed is introduced into the common liquid chamber 16 and the individual liquid chambers 17.

[0016] The liquid ejection head 12 may be formed with an outlet path 19. The outlet path 19 is a space within the liquid ejection head 12 through which the liquid flows. The outlet path 19 is a space for leading out the liquid from the liquid ejection head 12. Therefore, the liquid can flow within the liquid ejection head 12 from the introduction path 15 to the outlet path 19. If the liquid remains for a long time, there is a risk that the liquid will thicken or settle. By allowing the liquid to flow within the liquid ejection head 12, the risk that the liquid will thicken or settle within the liquid ejection head 12 is reduced.

[0017] The outlet path 19 extends from the introduction path 15, the common liquid chamber 16, or the individual liquid chamber 17. In one example, the outlet path 19 extends from the common liquid chamber 16. Therefore, the liquid passes through the liquid ejection head 12 by flowing through the introduction path 15, the common liquid chamber 16, and the outlet path 19 in that order. The outlet path 19 may extend from the introduction path 15 or from the individual liquid chamber 17. The outlet path 19 may extend from the introduction path 15 so that the liquid passes through the liquid ejection head 12 without passing through the filter 18.

[0018] A negative pressure is usually maintained inside the liquid ejection head 12. This is to form a meniscus in the nozzle 13. This allows the liquid ejection head 12 to eject the liquid appropriately. It is preferable to maintain a negative pressure inside the liquid ejection head 12 even when the liquid flows from the inlet path 15 to the outlet path 19. If the negative pressure in the liquid ejection head 12 is eliminated, the meniscus may be destroyed. If the meniscus is destroyed, it is necessary to form a meniscus again in the nozzle 13.

[0019] The liquid ejection device 11 includes a liquid flow mechanism 21. The liquid flow mechanism 21 supplies the liquid to the liquid ejection head 12 by causing the liquid to flow. In addition to causing the liquid to flow, the liquid flow mechanism 21 may also cause a moisturizing liquid to flow. The moisturizing liquid is a liquid for moisturizing the liquid. The moisturizing liquid is, for example, a glycerin aqueous solution.

[0020] The liquid flow mechanism 21 may be connected to a liquid supply source 22 and a moisture supply source 23. The liquid supply source 22 contains liquid. The moisture supply source 23 contains moisture, i.e., water. The liquid supply source 22 and the moisture supply source 23 may be a cartridge or a pack that is detachable from the liquid ejection device 11, or may be a tank that can be replenished with liquid.

[0021] The liquid flow mechanism 21 may have a first tank 25 and a second tank 26. The first tank 25 can store the liquid to be supplied to the liquid ejection head 12. The second tank 26 can store the liquid recovered from the liquid ejection head 12.

[0022] The second tank 26 may have a moisture permeable membrane 28. The moisture permeable membrane 28 divides the inside of the second tank 26 into a liquid chamber 29 and a moisturizer chamber 30. The liquid chamber 29 is capable of containing liquid. Liquid is supplied to the liquid chamber 29 from the liquid supply source 22. The moisturizer chamber 30 is capable of containing moisturizer. Moisture is supplied to the moisturizer chamber 30 from the moisture supply source 23.

[0023] The moisture permeable membrane 28 is a membrane that allows gas to pass through but does not allow liquid to pass through. Therefore, the moisture permeable membrane 28 separates the liquid stored in the liquid chamber 29 and the moisturizing liquid stored in the moisturizing liquid chamber 30 so that they do not mix. The moisture permeable membrane 28 is a porous membrane in which a plurality of pores are formed. A meniscus is generated in these pores due to the surface tension of the liquid. This allows gas to pass through the moisture permeable membrane 28 but does not allow liquid to pass through. The moisturizing liquid moisturizes the liquid by supplying moisture to the liquid through the moisture permeable membrane 28.

[0024] The liquid flow mechanism 21 may have a liquid supply flow path 32 and a moisture supply flow path 33. The liquid supply flow path 32 is connected to the liquid supply source 22 and the liquid chamber 29. The moisture supply flow path 33 is connected to the moisture supply source 23 and the moisturizing liquid chamber 30.

[0025] The liquid flow mechanism 21 may have a liquid supply valve 34 and a water supply valve 35. The liquid supply valve 34 is located in the liquid supply flow path 32. When the liquid supply valve 34 is open, liquid can be supplied from the liquid supply source 22 to the second tank 26. The water supply valve 35 is located in the water supply flow path 33. When the water supply valve 35 is open, water can be supplied from the water supply source 23 to the second tank 26. Normally, the liquid supply valve 34 and the water supply valve 35 are closed. The liquid supply valve 34 is opened when it is necessary to supply liquid to the second tank 26. The water supply valve 35 is opened when it is necessary to supply water to the second tank 26.

[0026] The liquid flow mechanism 21 may have an agitator 37. The agitator 37 is attached to the second tank 26. The agitator 37 agitates the moisturizer stored in the moisturizer chamber 30. The agitator 37 agitates the moisturizer, thereby making the concentration of the moisturizer uniform. This reduces the risk of the concentration of the moisturizer becoming too high.

[0027] The agitation unit 37 may have an agitation flow path 38 and an agitation pump 39. The agitation flow path 38 is connected to the moisturizer chamber 30 and the moisture supply flow path 33. The agitation pump 39 is located in the agitation flow path 38. The agitation pump 39 circulates the moisturizer in the second tank 26 through the agitation flow path 38. This causes the moisturizer to be agitated.

[0028] The liquid flow mechanism 21 may have a connection flow path 41, a positive pressure flow path 42, and a negative pressure flow path 43. The connection flow path 41 connects the second tank 26 and the first tank 25. The positive pressure flow path 42 connects the first tank 25 and the liquid ejection head 12. That is, the first tank 25 is connected to the positive pressure flow path 42. The negative pressure flow path 43 connects the liquid ejection head 12 and the second tank 26. That is, the second tank 26 is connected to the negative pressure flow path 43. The connection flow path 41, the positive pressure flow path 42, and the negative pressure flow path 43 circulate the liquid and supply the liquid to the liquid ejection head 12.

[0029] When circulating, the liquid flows from the second tank 26 to the first tank 25 through the connection flow path 41. When circulating, the liquid flows from the first tank 25 to the liquid ejection head 12 through the positive pressure flow path 42. When circulating, the liquid flows from the liquid ejection head 12 to the second tank 26 through the negative pressure flow path 43. The positive pressure flow path 42 is a flow path for supplying the liquid to the liquid ejection head 12. The negative pressure flow path 43 is a flow path for recovering the liquid from the liquid ejection head 12.

[0030] The liquid flow mechanism 21 may include a liquid delivery section 45 , a pressure increase pump 46 , a pressure decrease pump 47 , a first atmosphere release valve 48 , and a second atmosphere release valve 49 . The liquid delivery section 45 is located in the connection flow path 41. The liquid delivery section 45 delivers liquid from the second tank 26 to the first tank 25 via the connection flow path 41.

[0031] The pressurizing pump 46 is capable of pressurizing the inside of the first tank 25. For example, the pressurizing pump 46 may pressurize the inside of the first tank 25 by sending air into the first tank 25. When the pressurizing pump 46 pressurizes the inside of the first tank 25, the liquid in the first tank 25 flows out into the positive pressure flow path 42.

[0032] The decompression pump 47 is capable of reducing the pressure inside the second tank 26. For example, the decompression pump 47 may reduce the pressure inside the second tank 26 by drawing air out of the second tank 26. The decompression pump 47 normally reduces the pressure inside the second tank 26 so that the inside of the liquid ejection head 12 is maintained at a predetermined negative pressure.

[0033] When the decompression pump 47 reduces the pressure inside the second tank 26, liquid flows into the second tank 26. For example, when the decompression pump 47 is driven with the liquid supply valve 34 open, liquid flows into the second tank 26 from the liquid supply source 22 through the liquid supply flow path 32. When the decompression pump 47 is driven with the water supply valve 35 open, liquid flows into the second tank 26 from the water supply source 23 through the water supply flow path 33. When the decompression pump 47 is driven with the liquid supply valve 34 and the water supply valve 35 closed, liquid flows into the second tank 26 from the liquid ejection head 12 through the negative pressure flow path 43.

[0034] The first atmosphere release valve 48 is connected to the first tank 25. The first atmosphere release valve 48 is capable of opening the inside of the first tank 25 to the atmosphere. The first atmosphere release valve 48 is capable of making the pressure applied to the liquid in the first tank 25 equal to atmospheric pressure.

[0035] The second atmosphere release valve 49 is connected to the second tank 26. The second atmosphere release valve 49 is capable of opening the inside of the second tank 26 to the atmosphere. The second atmosphere release valve 49 is capable of making the pressure applied to the liquid in the second tank 26 equal to atmospheric pressure.

[0036] The liquid flow mechanism 21 may include a positive pressure adjustment mechanism 51 and a negative pressure adjustment mechanism 52. The positive pressure adjustment mechanism 51 is provided in the positive pressure flow path 42. The positive pressure adjustment mechanism 51 adjusts the positive pressure on the liquid ejection head 12 side. The negative pressure adjustment mechanism 52 is provided in the negative pressure flow path 43. The negative pressure adjustment mechanism 52 adjusts the negative pressure on the liquid ejection head 12 side.

[0037] <Positive pressure adjustment mechanism> As shown in FIG. 2, the positive pressure adjustment mechanism 51 includes a supply chamber 54, a pressure chamber 55, a pressurizing section 56, a first communication passage 57, a second communication passage 58, an opening / closing section 59, and a first seal section 60.

[0038] Supply chamber 54 has a first inlet 62, which is an example of an inlet through which liquid flows in. The pressure chamber 55 is provided downstream of the supply chamber 54. The pressure chamber 55 has a first flexible portion 63 which is an example of a flexible portion. The first flexible portion 63 is formed of a flexible member having flexibility, such as a diaphragm. The pressure chamber 55 has a first outlet 64 which is an example of an outlet through which the liquid flows out.

[0039] The pressurizing portion 56 pressurizes the first flexible portion 63 in a first direction D1 in which the volume of the pressure chamber 55 decreases. The pressurizing portion 56 is provided outside the pressure chamber 55. The pressurizing portion 56 presses the opening / closing portion 59 via the first flexible portion 63. The pressurizing portion 56 is, for example, a spring.

[0040] First communication passage 57 communicates supply chamber 54 with pressure chamber 55. The inner diameter of first communication passage 57 may be substantially the same as the inner diameter of second communication passage 58. The second communication passage 58 communicates between the supply chamber 54 and the pressure chamber 55. The second communication passage 58 is provided coaxially with the first communication passage 57. The first flexible portion 63 and the pressure portion 56 may be located on the axis of the first communication passage 57 and the second communication passage 58. The second communication passage 58 is located closer to the first flexible portion 63 than the first communication passage 57. The pressure portion 56, the first flexible portion 63, the second communication passage 58, and the first communication passage 57 may be arranged in this order in the first direction D1.

[0041] The opening / closing unit 59 has a first shaft portion 66 which is an example of a shaft portion, and a first valve portion 67 which is an example of a valve portion. The first valve portion 67 may have a flow path 68 and a second seal portion 69. The first shaft portion 66 is inserted into the first communication passage 57 and the second communication passage 58. At least a portion of the first shaft portion 66 is disposed in the pressure chamber 55. The first shaft portion 66 is capable of contacting the first flexible portion 63. The first shaft portion 66 moves in response to the displacement of the first flexible portion 63. The first shaft portion 66 in this embodiment is fixed to the first flexible portion 63. The first shaft portion 66 may be rod-shaped. The first shaft portion 66 may be cylindrical. The diameter of the first shaft portion 66 is smaller than the inner diameter of the first communication passage 57. The diameter of the first shaft portion 66 is smaller than the inner diameter of the second communication passage 58.

[0042] The first valve portion 67 is connected to the first shaft portion 66. The first valve portion 67 is capable of opening and closing the first communication passage 57. The first valve portion 67 is capable of restricting the flow of liquid from the supply chamber 54 to the pressure chamber 55. The first shaft portion 66 and the second seal portion 69 are capable of moving relative to the inner periphery of the first communication passage 57.

[0043] 3, the flow passage 68 is provided on the inner circumference of the first communication passage 57. The flow passage 68 connects the first communication passage 57 and the pressure chamber 55. The opening / closing unit 59 may have a plurality of flow passages 68. The plurality of flow passages 68 may be formed radially from the first communication passage 57.

[0044] As shown in Fig. 2, first seal portion 60 and second seal portion 69 move together with first shaft portion 66. First shaft portion 66, first seal portion 60, and second seal portion 69 are movable between a closed position shown by a solid line in Fig. 2 and an open position shown by a two-dot chain line in Fig. 2. When second seal portion 69 is in the closed position, flow path 68 does not communicate between supply chamber 54 and pressure chamber 55. When second seal portion 69 is in the open position, flow path 68 communicates between supply chamber 54 and pressure chamber 55.

[0045] The first seal portion 60 is provided on the outer periphery of the first shaft portion 66. The first seal portion 60 provides a seal with the inner periphery of the second communication passage 58. The first seal portion 60 may be annular. The first seal portion 60 has a first arm portion 60a and a second arm portion 60b. The first arm portion 60a and the second arm portion 60b have surfaces facing each other that receive pressure from the liquid in the supply chamber 54, and have opposite surfaces that receive pressure from the liquid in the pressure chamber 55.

[0046] The first arm 60a is located inside the second arm 60b. The first arm 60a approaches the outer periphery of the first shaft 66 as it moves in the first direction D1. The tip of the first arm 60a can be in close contact with the first shaft 66.

[0047] The second arm 60b is positioned outside the first arm 60a. The second arm 60b approaches the inner circumference of the second communication passage 58 as it moves in the first direction D1. The tip of the second arm 60b can be in close contact with the inner surface of the second communication passage 58.

[0048] The second seal portion 69 is provided on the outer periphery of the first shaft portion 66. The second seal portion 69 provides a seal between the inner periphery of the first communication passage 57 and the outer periphery of the first shaft portion 66. The second seal portion 69 may be annular. The second seal portion 69 has a third arm portion 69c and a fourth arm portion 69d. The third arm portion 69c and the fourth arm portion 69d have surfaces facing each other that receive pressure from the liquid in the supply chamber 54, and have opposite surfaces that receive pressure from the liquid in the pressure chamber 55.

[0049] The third arm 69c is located inside the fourth arm 69d. The third arm 69c approaches the outer periphery of the first shaft 66 as it moves in the direction opposite to the first direction D1. The tip of the third arm 69c can be in close contact with the first shaft 66.

[0050] The fourth arm 69d is located outside the third arm 69c. The fourth arm 69d approaches the inner circumference of the first communication passage 57 as it moves in the direction opposite to the first direction D1. The tip of the fourth arm 69d can be in close contact with the inner surface of the first communication passage 57.

[0051] <Operation of the positive pressure adjustment mechanism> The positive pressure adjustment mechanism 51 reduces the pressure of the liquid that has flowed into the supply chamber 54, causing it to flow out of the pressure chamber 55. The pressure of the liquid flowing into the supply chamber 54 and the pressure of the liquid flowing out of the pressure chamber 55 are both positive pressures.

[0052] The first shaft portion 66 moves in response to fluctuations in pressure within the pressure chamber 55. When the pressure within the pressure chamber 55 drops, the first shaft portion 66 is pushed by the first flexible portion 63 and moves to the open position. The second seal portion 69 moves to the open position together with the first shaft portion 66. As a result, the supply chamber 54 and the pressure chamber 55 communicate with each other, and liquid is supplied from the supply chamber 54 to the pressure chamber 55. The first seal portion 60 closes the second communication passage 58 whether it is in the open position or the closed position.

[0053] When the pressure in the pressure chamber 55 increases, the first flexible portion 63 moves in a direction away from the second communication passage 58. The first shaft portion 66 moves to the closed position together with the first flexible portion 63. As a result, the supply of liquid from the supply chamber 54 to the pressure chamber 55 is stopped.

[0054] The sealing performance of the first seal portion 60 and the second seal portion 69 changes according to the pressure in the supply chamber 54. Specifically, when the pressure in the supply chamber 54 rises, the liquid in the supply chamber 54 pushes the first seal portion 60 and the second seal portion 69 to spread apart. Specifically, the first seal portion 60 receives a force such that the tip of the first arm portion 60a and the tip of the second arm portion 60b move away from each other, thereby improving the sealing performance between the first shaft portion 66 and the second communication passage 58. The second seal portion 69 receives a force such that the tip of the third arm portion 69c and the tip of the fourth arm portion 69d move away from each other, thereby improving the sealing performance between the first shaft portion 66 and the first communication passage 57. The first seal portion 60 and the second seal portion 69 may be the same but provided upside down. The area of ​​the first seal portion 60 in contact with the liquid in the supply chamber 54 may be approximately the same as the area of ​​the second seal portion 69 in contact with the liquid in the supply chamber 54. In this case, even if the pressure inside the supply chamber 54 increases, the first shaft portion 66 will not move from the closed position.

[0055] <Negative pressure adjustment mechanism> As shown in FIG. 4, the negative pressure adjustment mechanism 52 may include an upstream chamber 71, a downstream chamber 72, a third communication passage 73, a restricting portion 74, a third seal portion 75, and a biasing member .

[0056] The downstream chamber 72 has a second outlet 78 through which liquid exits. The upstream chamber 71 is provided upstream of the downstream chamber 72. The upstream chamber 71 has a second flexible portion 79. The second flexible portion 79 is formed of a flexible member having flexibility, such as a diaphragm. The upstream chamber 71 has a second inlet 80 through which the liquid flows in.

[0057] The third communication passage 73 communicates between the upstream chamber 71 and the downstream chamber 72 . The restricting portion 74 is provided in the upstream chamber 71. The restricting portion 74 is capable of restricting the flow of liquid from the upstream chamber 71 to the downstream chamber 72. The restricting portion 74 may have a second shaft portion 82 and a second valve portion 83. The second shaft portion 82 and the second valve portion 83 may be integrally configured.

[0058] The second shaft portion 82 may be rod-shaped. The second shaft portion 82 may be cylindrical. The tip of the second shaft portion 82 is capable of contacting the second flexible portion 79. The restricting portion 74 moves in accordance with the displacement of the second flexible portion 79.

[0059] The second valve portion 83 is connected to the second shaft portion 82. The second valve portion 83 may be cylindrical. The second valve portion 83 may be plate-shaped. The diameter of the second valve portion 83 is larger than the diameter of the second shaft portion 82 and the inner diameter of the third communication passage 73.

[0060] The third seal portion 75 may be provided in the upstream chamber 71. The third seal portion 75 may be provided around the third communication passage 73. The third seal portion 75 seals between the restriction portion 74 and the inner surface of the upstream chamber 71. The restriction portion 74 closes the third communication passage 73 as the second valve portion 83 comes into close contact with the third seal portion 75.

[0061] The biasing member 76 is provided in the downstream chamber 72. A portion of the biasing member 76 is inserted into the third communication passage 73. The biasing member 76 presses the restricting portion 74 in a direction away from the third communication passage 73. The biasing member 76 is, for example, a spring.

[0062] <Operation of the negative pressure adjustment mechanism> The pressure in the upstream chamber 71 and the pressure in the downstream chamber 72 are both negative pressures. The negative pressure adjustment mechanism 52 makes the magnitude of the negative pressure in the upstream chamber 71 smaller than the magnitude of the negative pressure in the downstream chamber 72.

[0063] When the negative pressure in the upstream chamber 71 decreases, the force with which the liquid in the upstream chamber 71 pulls the second flexible portion 79 weakens. When the force with which the liquid in the upstream chamber 71 pulls the second flexible portion 79 becomes weaker than the force with which the biasing member 76 presses the second flexible portion 79 via the restricting portion 74, the restricting portion 74 opens the third communication passage 73. Because the negative pressure in the upstream chamber 71 is smaller than the negative pressure in the downstream chamber 72, when the third communication passage 73 is opened, the negative pressure in the upstream chamber 71 increases.

[0064] When the negative pressure in the upstream chamber 71 increases, the force with which the liquid in the upstream chamber 71 pulls the second flexible portion 79 increases. When the force with which the liquid in the upstream chamber 71 pulls the second flexible portion 79 becomes stronger than the force with which the biasing member 76 presses the second flexible portion 79 via the restricting portion 74, the restricting portion 74 closes the third communication passage 73.

[0065] <Operation of the embodiment> The operation of this embodiment will be described. The pressure of the liquid supplied from the first tank 25 to the liquid ejection head 12 is adjusted by the positive pressure adjustment mechanism 51. Therefore, the liquid supplied to the liquid ejection head 12 is at a pressure lower than the pressure in the pressurized first tank 25.

[0066] The pressure of the liquid recovered from the liquid ejection head 12 is adjusted by the negative pressure adjustment mechanism 52. Therefore, the negative pressure applied to the liquid ejection head 12 is smaller than the negative pressure in the reduced second tank .

[0067] <Effects of the embodiment> The effects of this embodiment will be described. (1-1) The first seal portion 60 has a first arm portion 60a and a second arm portion 60b. The first arm portion 60a approaches the outer periphery of the first shaft portion 66 as it moves in the first direction D1. The second arm portion 60b approaches the inner periphery of the second communication passage 58 as it moves in the first direction D1. When the pressure in the supply chamber 54 is high, the first seal portion 60 receives a force to open the first arm portion 60a and the second arm portion 60b, and the sealing force is increased. Therefore, even if the pressure in the supply chamber 54 increases, the leakage of liquid from the supply chamber 54 to the pressure chamber 55 via the second communication passage 58 can be reduced. When the pressure in the supply chamber 54 decreases, the force acting on the first seal portion 60 to open the first arm portion 60a and the second arm portion 60b decreases, and the frictional resistance also decreases. Therefore, the leakage of liquid can be reduced while reducing the frictional resistance.

[0068] (1-2) Second seal portion 69 seals between first communication passage 57 and first shaft portion 66. First shaft portion 66 and second seal portion 69 move relative to the inner periphery of first communication passage 57 to switch the communication state between supply chamber 54 and pressure chamber 55, thereby reducing leakage of liquid from first communication passage 57.

[0069] (1-3) The positive pressure adjustment mechanism 51 is provided in the positive pressure flow path 42. Therefore, the pressure of the liquid supplied to the liquid ejection head 12 can be stabilized. (1-4) The connection flow path 41 connects the second tank 26 connected to the negative pressure flow path 43 and the first tank 25 connected to the positive pressure flow path 42. Therefore, the liquid recovered from the liquid ejection head 12 can be supplied to the liquid ejection head 12 again.

[0070] [Example of change] This embodiment can be modified as follows. This embodiment and the following modifications can be combined to the extent that there is no technical contradiction. In this embodiment and the following modifications, the same components are denoted by the same reference numerals, and redundant explanations will be omitted.

[0071] <First change example> 5, the first seal portion 60 may have a fifth arm portion 60e which is an example of an arm portion. The first seal portion 60 is provided on the first shaft portion 66 and moves together with the first shaft portion 66. The fifth arm portion 60e is provided on the outer periphery of the first shaft portion 66. The fifth arm portion 60e approaches the inner periphery of the second communication passage 58 as it moves in the first direction D1.

[0072] The second seal portion 69 may have a sixth arm portion 69f which is an example of an arm portion. The second seal portion 69 is provided on the first shaft portion 66. The second seal portion 69 moves together with the first shaft portion 66. The sixth arm portion 69f is provided on the outer periphery of the first shaft portion 66. The sixth arm portion 69f approaches the inner periphery of the first communication passage 57 as it moves in the direction opposite to the first direction D1.

[0073] The first seal portion 60 and the second seal portion 69 may be integrally formed with the first shaft portion 66. For example, the first seal portion 60, the second seal portion 69, and the first shaft portion 66 may be formed by two-color molding.

[0074] First seal portion 60 and second seal portion 69 may be the same but provided upside down. The area of ​​first seal portion 60 in contact with the liquid in supply chamber 54 may be approximately the same as the area of ​​second seal portion 69 in contact with the liquid in supply chamber 54.

[0075] <Operation of the first modified example> When the pressure in the pressure chamber 55 drops, the first shaft portion 66 is pushed by the pressurizing portion 56 and the first flexible portion 63 and moves in the first direction D1. The second seal portion 69 moves to the open position together with the first shaft portion 66. As a result, the supply chamber 54 and the pressure chamber 55 communicate with each other, and liquid is supplied from the supply chamber 54 to the pressure chamber 55.

[0076] When the pressure in the pressure chamber 55 increases, the first flexible portion 63 moves in a direction away from the second communication passage 58. The first shaft portion 66 moves together with the first flexible portion 63 in a direction opposite to the first direction D1. The first valve portion 67 moves to the closed position to close the first communication passage 57. As a result, the supply of liquid from the supply chamber 54 to the pressure chamber 55 is stopped.

[0077] The sealing performance of the first seal portion 60 and the second seal portion 69 changes according to the pressure in the supply chamber 54. Specifically, when the pressure in the supply chamber 54 increases, the liquid in the supply chamber 54 pushes the fifth arm portion 60e against the inner surface of the second communication passage 58. Therefore, the first seal portion 60 improves the sealing performance between the first shaft portion 66 and the second communication passage 58. When the pressure in the supply chamber 54 increases, the liquid in the supply chamber 54 pushes the sixth arm portion 69f against the inner surface of the first communication passage 57. Therefore, the second seal portion 69 improves the sealing performance between the first shaft portion 66 and the first communication passage 57. Even if the pressure in the supply chamber 54 increases, the first shaft portion 66 does not move from the closed position.

[0078] <Effects of the first modification> The first seal portion 60 has a fifth arm portion 60e. The fifth arm portion 60e approaches the inner circumference of the second communication passage 58 as it moves in the first direction D1. When the pressure in the supply chamber 54 is high, the first seal portion 60 receives a force such that the tip of the fifth arm portion 60e is pressed against the inner circumference of the second communication passage 58, and the sealing force is increased. Therefore, even if the pressure in the supply chamber 54 increases, the leakage of liquid from the supply chamber 54 to the pressure chamber 55 via the second communication passage 58 can be reduced. When the pressure in the supply chamber 54 decreases, the force applied to press the fifth arm portion 60e against the second communication passage 58 decreases, and the frictional resistance also decreases. Therefore, the leakage of liquid can be reduced while reducing the frictional resistance.

[0079] Second seal portion 69 has a sixth arm portion 69f. Sixth arm portion 69f approaches the inner circumference of first communication passage 57 as it moves in the opposite direction to first direction D1. Therefore, when the pressure in supply chamber 54 is high, the sealing power of second seal portion 69 increases, whereas when the pressure in supply chamber 54 is low, the sealing power of second seal portion 69 decreases. Therefore, it is possible to reduce liquid leakage while reducing frictional resistance.

[0080] <Second modification example> As shown in Fig. 6, the second seal portion 69 may be provided outside the first communication passage 57. The second seal portion 69 and the first valve portion 67 may be provided in the pressure chamber 55. The second seal portion 69 may be provided around the opening of the first communication passage 57 on the pressure chamber 55 side. The first valve portion 67 may be cylindrical. The first valve portion 67 may be plate-shaped. The diameter of the first valve portion 67 is larger than the diameter of the first shaft portion 66 and the inner diameter of the first communication passage 57.

[0081] The area of ​​first valve portion 67 in contact with the liquid in supply chamber 54 may be approximately the same as the area of ​​first seal portion 60 in contact with the liquid in supply chamber 54. First valve portion 67 closes first communication passage 57 by coming into close contact with second seal portion 69. First valve portion 67 is configured to close the opening of first communication passage 57 on the pressure chamber 55 side.

[0082] <Operation of the second modified example> When the pressure in the pressure chamber 55 drops, the first shaft portion 66 is pushed by the pressurizing portion 56 and the first flexible portion 63 and moves in the first direction D1. The first valve portion 67, which moves in the first direction D1 together with the first shaft portion 66, moves away from the second seal portion 69, thereby opening the first communication passage 57. As a result, liquid is supplied from the supply chamber 54 to the pressure chamber 55.

[0083] When the pressure in the pressure chamber 55 increases, the first flexible portion 63 moves in a direction away from the second communication passage 58. The first shaft portion 66 moves together with the first flexible portion 63 in a direction opposite to the first direction D1. The first valve portion 67, which has moved to the closed position, comes into close contact with the second seal portion 69 to close the first communication passage 57. This stops the supply of liquid from the supply chamber 54 to the pressure chamber 55. Even if the pressure in the supply chamber 54 increases, the first shaft portion 66 does not move from the closed position.

[0084] <Effects of the second amendment> The first valve portion 67 is capable of closing the first communication passage 57 from the side of the pressure chamber 55. Therefore, the opening / closing portion 59 can be configured with a simple structure.

[0085] <Third modification example> In a second modified example, the second seal portion 69 may be provided in the first valve portion 67. The second seal portion 69 may be an O-ring having a circular cross section.

[0086] <Fourth modified example> As shown in FIG. 7, the first seal portion 60 may have a seventh arm portion 60g, which is an example of an arm portion. The first seal portion 60 is provided on the inner circumference of the second communication passage 58. The first seal portion 60 seals against the outer circumference of the first shaft portion 66. The first seal portion 60 slides relative to the moving first shaft portion 66. The first shaft portion 66 is movable relative to the first seal portion 60 and the second communication passage 58. The seventh arm portion 60g approaches the outer circumference of the first shaft portion 66 as it moves in the first direction D1.

[0087] The second seal portion 69 may have an eighth arm portion 69h, which is an example of an arm portion. The second seal portion 69 is provided on the inner circumference of the first communication passage 57. The second seal portion 69 seals against the outer circumference of the first shaft portion 66. The second seal portion 69 slides relative to the moving first shaft portion 66. The first shaft portion 66 is movable relative to the second seal portion 69 and the first communication passage 57. The eighth arm portion 69h approaches the outer circumference of the first shaft portion 66 as it moves in the opposite direction to the first direction D1.

[0088] The first seal portion 60 may be configured integrally with a member that configures the second communication passage 58. The second seal portion 69 may be configured integrally with a member that configures the first communication passage 57. For example, the first seal portion 60 and the second seal portion 69 may be molded in two colors on the inner surfaces of the first communication passage 57 and the second communication passage 58.

[0089] Flow path 68 is provided in first shaft portion 66. First shaft portion 66 is movable between a closed position shown by a solid line in Fig. 7 and an open position shown by a two-dot chain line in Fig. 7. When second seal portion 69 is in the closed position, flow path 68 does not communicate between supply chamber 54 and pressure chamber 55. When second seal portion 69 is in the open position, flow path 68 communicates between supply chamber 54 and pressure chamber 55.

[0090] <Operation of the Fourth Modification> When the pressure in the pressure chamber 55 drops, the first shaft portion 66 is pushed by the pressure applying portion 56 and the first flexible portion 63 and moves in the first direction D1. When the first shaft portion 66 moves to the open position, the flow path 68 connects the supply chamber 54 and the pressure chamber 55. Liquid is supplied from the supply chamber 54 to the pressure chamber 55.

[0091] When the pressure in the pressure chamber 55 increases, the first flexible portion 63 moves in a direction away from the second communication passage 58. When the first shaft portion 66 moves to the closing position, the supply of liquid from the supply chamber 54 to the pressure chamber 55 stops.

[0092] When the pressure in the supply chamber 54 increases, the liquid in the supply chamber 54 pushes the seventh arm 60g against the outer periphery of the first shaft 66. Therefore, the first seal 60 improves the sealing between the first shaft 66 and the second communication passage 58. When the pressure in the supply chamber 54 increases, the liquid in the supply chamber 54 pushes the eighth arm 69h against the outer surface of the first shaft 66. Therefore, the second seal 69 improves the sealing between the first shaft 66 and the first communication passage 57. The first seal 60 and the second seal 69 may be the same but provided upside down. The area of ​​the first seal 60 in contact with the liquid in the supply chamber 54 may be approximately the same as the area of ​​the second seal 69 in contact with the liquid in the supply chamber 54. In this case, even if the pressure in the supply chamber 54 increases, the first shaft 66 does not move from the closed position.

[0093] <Effects of the Fourth Amendment> The first seal portion 60 has a seventh arm portion 60g. The seventh arm portion 60g approaches the outer periphery of the first shaft portion 66 as it moves in the first direction D1. When the pressure in the supply chamber 54 is high, the first seal portion 60 receives a force such that the tip of the seventh arm portion 60g is pressed against the first shaft portion 66, and the sealing force is increased. Therefore, even if the pressure in the supply chamber 54 increases, the leakage of liquid from the supply chamber 54 to the pressure chamber 55 via the second communication passage 58 can be reduced. When the pressure in the supply chamber 54 decreases, the force applied to press the seventh arm portion 60g against the first shaft portion 66 decreases, and the frictional resistance also decreases. Therefore, the leakage of liquid can be reduced while reducing the frictional resistance.

[0094] The second seal portion 69 seals between the first communication passage 57 and the first shaft portion 66. The first shaft portion 66 moves relative to the second seal portion 69 and the inner periphery of the first communication passage 57 to switch the communication state between the supply chamber 54 and the pressure chamber 55, thereby reducing leakage of liquid from the first communication passage 57.

[0095] Second seal portion 69 has eighth arm portion 69h. Eighth arm portion 69h approaches the outer periphery of first shaft portion 66 as it moves in the opposite direction to first direction D1. Therefore, when the pressure in supply chamber 54 is high, the sealing power of second seal portion 69 increases, whereas when the pressure in supply chamber 54 is low, the sealing power of second seal portion 69 decreases. Therefore, it is possible to reduce liquid leakage while reducing frictional resistance.

[0096] <Fifth modified example> 8, at least one of the positive pressure adjustment mechanism 51 and the negative pressure adjustment mechanism 52 may be provided in the air flow path. The air flow path communicates with the liquid ejection head 12 via a flow path that supplies liquid.

[0097] The positive pressure adjustment mechanism 51 may be provided in a flow path between the pressurizing pump 46 and the first tank 25. The flow path connects the pressurizing pump 46 and the supply chamber 54. The flow path connects the pressure chamber 55 and the first tank 25. The positive pressure adjustment mechanism 51 may adjust the pressurized air supplied by the pressurizing pump 46 and supply it to the first tank 25.

[0098] The negative pressure adjustment mechanism 52 may be provided in a flow path between the decompression pump 47 and the second tank 26. The flow path connects the second tank 26 and the upstream chamber 71. The flow path connects the downstream chamber 72 and the decompression pump 47. The negative pressure adjustment mechanism 52 may adjust the negative pressure by the decompression pump 47 and apply it to the second tank 26.

[0099] <Sixth Change Example> 9, the liquid ejection device 11 may include a plurality of positive pressure adjustment mechanisms 51. The liquid ejection device 11 may include a plurality of negative pressure adjustment mechanisms 52. The plurality of positive pressure adjustment mechanisms 51 may have different pressures after adjustment. The plurality of negative pressure adjustment mechanisms 52 may have different pressures after adjustment.

[0100] The liquid ejection device 11 may include a plurality of positive pressure flow paths 42, a plurality of negative pressure flow paths 43, and a plurality of on-off valves 97. The positive pressure flow path 42 may be provided with an on-off valve 97 and a positive pressure adjustment mechanism 51. The negative pressure flow path 43 may be provided with a negative pressure adjustment mechanism 52 and an on-off valve 97. The plurality of positive pressure adjustment mechanisms 51 may be provided in parallel. The plurality of negative pressure adjustment mechanisms 52 may be provided in parallel. The liquid ejection device 11 may select the positive pressure adjustment mechanism 51 and the negative pressure adjustment mechanism 52 to be used by opening and closing the on-off valve 97.

[0101] For example, when circulating the liquid, the liquid ejection device 11 may use a positive pressure adjustment mechanism 51 that adjusts the pressure to a small value and a negative pressure adjustment mechanism 52 that adjusts the negative pressure to a small value. During circulation, a small negative pressure may be applied to the liquid ejection head 12 while supplying the liquid at a low pressure to the liquid ejection head 12.

[0102] For example, when filling the liquid ejection head 12 with liquid, the liquid ejection device 11 may use a positive pressure adjustment mechanism 51 that produces a large adjusted pressure, and a negative pressure adjustment mechanism 52 that produces a large adjusted negative pressure. That is, when filling, liquid at a large pressure may be supplied to the liquid ejection head 12, and a large negative pressure may be applied to the liquid ejection head 12.

[0103] <Seventh Change Example> 10, multiple positive pressure adjustment mechanisms 51 may be provided in one positive pressure flow path 42. Multiple positive pressure adjustment mechanisms 51 may be provided in series. A positive pressure adjustment mechanism 51 having a higher post-adjustment pressure may be provided at a position closer to the first tank 25 than a positive pressure adjustment mechanism 51 having a lower post-adjustment pressure. The multiple positive pressure adjustment mechanisms 51 may gradually reduce the pressure of the liquid flowing from the first tank 25 to the liquid ejection head 12. This allows the pressure of the liquid supplied to the liquid ejection head 12 to be adjusted with high precision.

[0104] The multiple negative pressure adjustment mechanisms 52 may be provided in one negative pressure flow path 43. The multiple negative pressure adjustment mechanisms 52 may be provided in series. The negative pressure adjustment mechanism 52 that provides a smaller negative pressure after adjustment may be provided at a position closer to the liquid ejection head 12 than the negative pressure adjustment mechanism 52 that provides a larger negative pressure after adjustment. The multiple negative pressure adjustment mechanisms 52 may gradually reduce the negative pressure from the second tank 26 to the liquid ejection head 12. This allows the negative pressure applied to the liquid ejection head 12 to be adjusted with high precision.

[0105] <Example of change No. 8> 11, the pressure pump 46 may be provided in the positive pressure flow path 42. The pressure pump 46 may be provided between the first tank 25 and the positive pressure adjustment mechanism 51. The pressure pump 46 sends the liquid in the first tank 25 toward the liquid ejection head 12.

[0106] The decompression pump 47 may be provided in the negative pressure flow path 43. The decompression pump 47 may be provided between the negative pressure adjustment mechanism 52 and the second tank . The decompression pump 47 sends liquid from the liquid ejection head 12 toward the second tank .

[0107] <9th change example> 12, the liquid ejection device 11 includes a liquid ejection head 12, a positive pressure flow path 42, and a positive pressure adjustment mechanism 51. The positive pressure flow path 42 may be connected to a liquid supply source 22. A pressure pump 46 may pressurize the liquid stored in the liquid supply source 22. A first atmosphere release valve 48 can make the pressure applied to the liquid in the liquid supply source 22 atmospheric pressure.

[0108] <10th change example> As shown in FIG. 13, the positive pressure adjustment mechanism 51 may be provided in the flow path between the pressure pump 46 and the liquid supply source 22.

[0109] <11th Change Example> 14, the liquid ejection device 11 may include a plurality of positive pressure flow paths 42, a plurality of positive pressure adjustment mechanisms 51, and a plurality of on-off valves 97. The plurality of positive pressure adjustment mechanisms 51 may be provided in parallel to the plurality of positive pressure flow paths 42.

[0110] <12th Change Example> 15, the liquid ejection device 11 may include a plurality of positive pressure adjustment mechanisms 51. The plurality of positive pressure adjustment mechanisms 51 may be provided in series in the positive pressure flow path .

[0111] <13th Change Example> 16, the pressure pump 46 may be provided in the positive pressure flow path 42. The pressure pump 46 may be provided between the liquid supply source 22 and the positive pressure adjustment mechanism 51.

[0112] <Other changes> The liquid ejection device 11 may include one positive pressure adjustment mechanism 51 and a plurality of negative pressure adjustment mechanisms 52. The liquid ejection device 11 may include a plurality of positive pressure adjustment mechanisms 51 and one negative pressure adjustment mechanism 52.

[0113] A plurality of positive pressure adjustment mechanisms 51 may be provided in parallel, and a plurality of negative pressure adjustment mechanisms 52 may be provided in series. A plurality of positive pressure adjustment mechanisms 51 may be provided in series, and a plurality of negative pressure adjustment mechanisms 52 may be provided in parallel.

[0114] The liquid ejection device 11 may include three or more positive pressure adjustment mechanisms 51. The three or more positive pressure adjustment mechanisms 51 may be arranged in series. The three or more positive pressure adjustment mechanisms 51 may be arranged such that at least two positive pressure adjustment mechanisms 51 are arranged in series, and another positive pressure adjustment mechanism 51 is arranged in parallel to the positive pressure adjustment mechanisms 51 arranged in series.

[0115] The liquid ejection device 11 may include three or more negative pressure adjustment mechanisms 52. The three or more negative pressure adjustment mechanisms 52 may be arranged in series. The three or more negative pressure adjustment mechanisms 52 may be arranged such that at least two negative pressure adjustment mechanisms 52 are arranged in series, and another negative pressure adjustment mechanism 52 is arranged in parallel to the negative pressure adjustment mechanisms 52 arranged in series.

[0116] The negative pressure flow path 43 may connect the liquid ejection head 12 and the first tank 25 . The second seal portion 69 that seals between the outer periphery of the first shaft portion 66 and the inner periphery of the first communication passage 57 may be an O-ring. For example, if the first shaft portion 66 is thin, the frictional resistance between the first communication passage 57 and the second seal portion 69 can be reduced even if it is an O-ring.

[0117] The positive pressure adjustment mechanism 51 may be any combination of the first seal portion 60 and the opening / closing portion 59 in the embodiment and modified examples. The liquid ejection device 11 may be a liquid ejection device that ejects or ejects liquid other than ink. The state of the liquid ejected from the liquid ejection device as minute droplets includes granular, teardrop, and thread-like tails. The liquid here may be any material that can be ejected from the liquid ejection device. For example, the liquid may be any state in which the substance is in a liquid phase, and includes fluids such as high or low viscosity liquids, sols, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals, and metal melts. The liquid includes not only liquids as one state of matter, but also particles of functional materials made of solids such as pigments and metal particles dissolved, dispersed, or mixed in a solvent. Representative examples of liquids include inks and liquid crystals as described in the above embodiment. Here, the ink includes various liquid compositions such as general water-based inks and oil-based inks, as well as gel inks and hot melt inks. Specific examples of the liquid ejection device include a device that ejects a liquid containing materials such as electrode materials and color materials in a dispersed or dissolved form, which are used in the manufacture of liquid crystal displays, electroluminescence displays, surface-emitting displays, and color filters. The liquid ejection device may be a device that ejects biological organic matter used in the manufacture of biochips, a device that ejects liquid as a sample used as a precision pipette, a textile printing device, a microdispenser, or the like. The liquid ejection device may be a device that ejects lubricating oil at a pinpoint onto precision machinery such as a watch or camera, or a device that ejects transparent resin liquid such as ultraviolet curing resin onto a substrate to form a micro hemispherical lens, optical lens, or the like used in optical communication elements. The liquid ejection device may be a device that ejects an etching liquid such as an acid or alkali to etch a substrate or the like.

[0118] The technical ideas and effects obtained from the above-described embodiment and modified examples will be described below. (A) A positive pressure adjustment mechanism includes a supply chamber having an inlet through which liquid flows in, a pressure chamber having a flexible portion formed of a flexible member, disposed downstream of the supply chamber and having an outlet through which the liquid flows out, a first communication passage connecting the supply chamber and the pressure chamber, a second communication passage disposed coaxially with the first communication passage and connecting the supply chamber and the pressure chamber, an opening / closing unit having an axis portion inserted into the first communication passage and the second communication passage and moving in response to displacement of the flexible portion, and a valve portion connected to the axis portion and capable of opening and closing the first communication passage, a first seal portion sealing between an outer periphery of the axis portion and an inner periphery of the second communication passage, and a pressurizing unit pressurizing the flexible portion in a first direction in which a volume of the pressure chamber decreases, and the first seal portion has a first arm portion approaching the outer periphery of the axis portion as it moves in the first direction, and a second arm portion approaching the inner periphery of the second communication passage as it moves in the first direction.

[0119] According to this configuration, the first seal portion has a first arm portion and a second arm portion. The first arm portion approaches the outer periphery of the shaft portion as it moves in the first direction. The second arm portion approaches the inner periphery of the second communication passage as it moves in the first direction. When the pressure in the supply chamber is high, the first seal portion receives a force to open the first arm portion and the second arm portion, and the sealing force is increased. Therefore, even if the pressure in the supply chamber increases, the leakage of liquid from the supply chamber to the pressure chamber via the second communication passage can be reduced. When the pressure in the supply chamber decreases, the force applied to the first seal portion to open the first arm portion and the second arm portion decreases, and the frictional resistance also decreases. Therefore, the leakage of liquid can be reduced while reducing the frictional resistance.

[0120] (B) A positive pressure adjustment mechanism includes a supply chamber having an inlet through which liquid flows in, a pressure chamber having a flexible portion formed of a flexible member, disposed downstream of the supply chamber and having an outlet through which the liquid flows out, a first communication passage connecting the supply chamber and the pressure chamber, a second communication passage disposed coaxially with the first communication passage and connecting the supply chamber and the pressure chamber, an opening / closing unit having a shaft portion inserted into the first communication passage and the second communication passage and moving in response to displacement of the flexible portion, and a valve portion connected to the shaft portion and capable of opening and closing the first communication passage, a first seal portion provided on the outer periphery of the shaft portion and sealing between the inner periphery of the second communication passage, and a pressurizing unit that pressurizes the flexible portion in a first direction in which the volume of the pressure chamber decreases, and the first seal portion has an arm portion that approaches the inner periphery of the second communication passage as it moves in the first direction.

[0121] According to this configuration, the first seal portion has an arm portion. The arm portion approaches the inner circumference of the second communication passage as it moves in the first direction. When the pressure in the supply chamber is high, the first seal portion receives a force such that the tip of the arm portion is pressed against the inner circumference of the second communication passage, increasing the sealing force. Therefore, even if the pressure in the supply chamber increases, leakage of liquid from the supply chamber to the pressure chamber via the second communication passage can be reduced. When the pressure in the supply chamber decreases, the force applied to press the arm portion against the second communication passage decreases, and the frictional resistance also decreases. Therefore, it is possible to reduce leakage of liquid while reducing frictional resistance.

[0122] (C) A positive pressure adjustment mechanism includes a supply chamber having an inlet through which liquid flows in, a pressure chamber having a flexible portion formed of a flexible member, disposed downstream of the supply chamber and having an outlet through which the liquid flows out, a first communication passage connecting the supply chamber and the pressure chamber, a second communication passage disposed coaxially with the first communication passage and connecting the supply chamber and the pressure chamber, an opening / closing unit having a shaft portion inserted into the first communication passage and the second communication passage and moving in response to displacement of the flexible portion, and a valve portion connected to the shaft portion and capable of opening and closing the first communication passage, a first seal portion disposed on an inner circumference of the second communication passage and sealing between the outer circumference of the shaft portion, and a pressurizing unit that pressurizes the flexible portion in a first direction in which the volume of the pressure chamber decreases, and the first seal portion has an arm portion that approaches the outer circumference of the shaft portion as it moves in the first direction.

[0123] According to this configuration, the first seal portion has an arm portion. The arm portion approaches the outer periphery of the shaft portion as it moves in the first direction. When the pressure in the supply chamber is high, the first seal portion receives a force such that the tip of the arm portion is pressed against the shaft portion, thereby increasing the sealing force. Therefore, even if the pressure in the supply chamber increases, leakage of liquid from the supply chamber to the pressure chamber via the second communication passage can be reduced. When the pressure in the supply chamber decreases, the force applied to press the arm portion against the shaft portion decreases, and the frictional resistance also decreases. Therefore, it is possible to reduce leakage of liquid while reducing frictional resistance.

[0124] (D) In ​​the positive pressure adjustment mechanism described in (A) to (C), the valve portion may be configured to close an opening of the first communication passage on the pressure chamber side. According to this configuration, the valve portion is capable of closing the first communication passage from the pressure chamber side, and therefore the opening / closing portion can be configured with a simple structure.

[0125] (E) In the positive pressure adjustment mechanism described in (A) to (C), the valve portion has a second seal portion that seals between an inner periphery of the first communication passage and an outer periphery of the shaft portion, and a flow path provided on the inner periphery of the first communication passage, the shaft portion and the second seal portion are movable relative to the inner periphery of the first communication passage, and the flow path may be configured to disconnect the supply chamber from the pressure chamber when the second seal portion is in a closed position, and to connect the supply chamber to the pressure chamber when the second seal portion is in an open position.

[0126] With this configuration, the second seal portion seals between the first communication passage and the shaft portion. The shaft portion and the second seal portion move relative to the inner circumference of the first communication passage to switch the communication state between the supply chamber and the pressure chamber, thereby reducing leakage of liquid from the first communication passage.

[0127] In the positive pressure adjustment mechanism described in (F) and (E), the second seal portion may be provided on the outer periphery of the shaft portion and may have an arm portion that approaches the inner periphery of the first communication passage as it extends in the direction opposite to the first direction.

[0128] According to this configuration, the second seal portion has an arm portion. The arm portion approaches the inner circumference of the first communication passage as it moves in the opposite direction to the first direction. Therefore, when the pressure in the supply chamber is high, the sealing power of the second seal portion increases, whereas when the pressure in the supply chamber is low, the sealing power of the second seal portion decreases. Therefore, it is possible to reduce the frictional resistance and the leakage of liquid.

[0129] (G) In the positive pressure adjustment mechanism described in (A) to (C), the valve portion has a second seal portion that seals between an inner periphery of the first communication passage and an outer periphery of the shaft portion, and a flow path provided in the shaft portion, the shaft portion is movable relative to the second seal portion and the first communication passage, and the flow path may disconnect the supply chamber from the pressure chamber when the shaft portion is in a closed position, and connect the supply chamber to the pressure chamber when the shaft portion is in an open position.

[0130] With this configuration, the second seal portion seals between the first communication passage and the shaft portion. The shaft portion moves relative to the second seal portion and the inner circumference of the first communication passage to switch the communication state between the supply chamber and the pressure chamber, thereby reducing leakage of liquid from the first communication passage.

[0131] In the pressure adjustment mechanism described in (H) and (G), the second seal portion may have an arm portion that is provided on an inner circumference of the first communication passage and approaches an outer circumference of the shaft portion as it extends in the direction opposite to the first direction.

[0132] According to this configuration, the second seal portion has an arm portion. The arm portion approaches the outer periphery of the shaft portion as it moves in the opposite direction to the first direction. Therefore, when the pressure in the supply chamber is high, the sealing power of the second seal portion increases, whereas when the pressure in the supply chamber is low, the sealing power of the second seal portion decreases. Therefore, it is possible to reduce the leakage of liquid while reducing the frictional resistance.

[0133] (I) A liquid ejection device includes a liquid ejection head capable of ejecting the liquid, a positive pressure flow path for supplying the liquid to the liquid ejection head, and a positive pressure adjustment mechanism described in (A) to (H) provided in the positive pressure flow path.

[0134] According to this configuration, the positive pressure adjustment mechanism is provided in the positive pressure flow path, so that the pressure of the liquid supplied to the liquid ejection head can be stabilized. (J) A liquid ejection device includes a liquid ejection head capable of ejecting the liquid, a positive pressure flow path for supplying the liquid to the liquid ejection head, a negative pressure flow path for recovering the liquid from the liquid ejection head, a positive pressure adjustment mechanism of the above-mentioned configuration provided in the positive pressure flow path, and a negative pressure adjustment mechanism provided in the negative pressure flow path for adjusting the negative pressure on the liquid ejection head side.

[0135] According to this configuration, it is possible to achieve the same effects as those of the above-mentioned liquid ejection device. (K) The liquid ejection device may further include a first tank connected to the positive pressure flow path and capable of storing the liquid to be supplied to the liquid ejection head, a second tank connected to the negative pressure flow path and capable of storing the liquid recovered from the liquid ejection head, a connecting flow path connecting the second tank and the first tank, a liquid delivery unit that sends the liquid from the second tank to the first tank via the communicating flow path, a pressure booster pump that can pressurize the first tank, and a pressure booster pump that can reduce the pressure in the second tank.

[0136] According to this configuration, the connection flow path connects the second tank connected to the negative pressure flow path and the first tank connected to the positive pressure flow path, so that the liquid recovered from the liquid ejection head can be supplied again to the liquid ejection head. [Explanation of symbols]

[0137] 11...liquid ejection device, 12...liquid ejection head, 13...nozzle, 14...nozzle surface, 15...inlet passage, 16...common liquid chamber, 17...individual liquid chamber, 18...filter, 19...outlet passage, 21...liquid flow mechanism, 22...liquid supply source, 23...moisture supply source, 25...first tank, 26...second tank, 28...moisture permeable membrane, 29...liquid chamber, 30...moisture liquid chamber, 32...liquid supply flow path, 33...moisture supply flow path, 34...liquid body supply valve, 35...water supply valve, 37...mixing section, 38...mixing flow path, 39...mixing pump, 41...connecting flow path, 42...positive pressure flow path, 43...negative pressure flow path, 45...liquid delivery section, 46...pressurizing pump, 47...decompressing pump, 48...first atmosphere release valve, 49...second atmosphere release valve, 51...positive pressure adjustment mechanism, 52...negative pressure adjustment mechanism, 54...supply chamber, 55...pressure chamber, 56...pressurizing section, 57...first communication passage, 58...second communication passage, 59...opening / closing portion, 60...first seal portion, 60a...first arm portion, 60b...second arm portion, 60e...fifth arm portion which is an example of an arm portion, 60g...seventh arm portion which is an example of an arm portion, 62...first inlet which is an example of an inlet, 63...first flexible portion which is an example of a flexible portion, 64...first outlet which is an example of an outlet, 66...first shaft portion which is an example of a shaft portion, 67...first valve portion which is an example of a valve portion, 68...flow path, 69...second seal portion a third arm portion, 69c...third arm portion, 69d...fourth arm portion, 69f...sixth arm portion which is an example of an arm portion, 69h...eighth arm portion which is an example of an arm portion, 71...upstream chamber, 72...downstream chamber, 73...third communication passage, 74...regulating portion, 75...third seal portion, 76...urge member, 78...second outlet port, 79...second flexible portion, 80...second inlet port, 82...second shaft portion, 83...second valve portion, 97...opening / closing valve, D1...first direction, M1...medium.

Claims

1. a supply chamber having an inlet through which liquid flows; a pressure chamber having a flexible portion formed by a flexible member, the pressure chamber being disposed downstream of the supply chamber and having an outlet through which the liquid flows out; a first communication passage that communicates the supply chamber and the pressure chamber; a second communication passage provided coaxially with the first communication passage and communicating between the supply chamber and the pressure chamber; an opening / closing unit including a shaft portion that is inserted into the first communication passage and the second communication passage and moves in response to a displacement of the flexible portion, and a valve portion that is connected to the shaft portion and is capable of opening and closing the first communication passage; a first seal portion that seals between an outer periphery of the shaft portion and an inner periphery of the second communication passage; a pressure applying section that applies pressure to the flexible section in a first direction in which the volume of the pressure chamber decreases; Equipped with A positive pressure adjustment mechanism characterized in that the first seal portion has a first arm portion that approaches the outer periphery of the shaft portion as it approaches the first direction, and a second arm portion that approaches the inner periphery of the second communication passage as it approaches the first direction.

2. a supply chamber having an inlet through which liquid flows; a pressure chamber having a flexible portion formed by a flexible member, the pressure chamber being disposed downstream of the supply chamber and having an outlet through which the liquid flows out; a first communication passage that communicates the supply chamber and the pressure chamber; a second communication passage provided coaxially with the first communication passage and communicating between the supply chamber and the pressure chamber; an opening / closing unit including a shaft portion that is inserted into the first communication passage and the second communication passage and moves in response to a displacement of the flexible portion, and a valve portion that is connected to the shaft portion and is capable of opening and closing the first communication passage; a first seal portion provided on an outer periphery of the shaft portion and sealing between the shaft portion and an inner periphery of the second communication passage; a pressure applying section that applies pressure to the flexible section in a first direction in which the volume of the pressure chamber decreases; Equipped with The positive pressure adjustment mechanism, wherein the first seal portion has an arm portion that approaches an inner circumference of the second communication passage as it advances in the first direction.

3. a supply chamber having an inlet through which liquid flows; a pressure chamber having a flexible portion formed by a flexible member, the pressure chamber being disposed downstream of the supply chamber and having an outlet through which the liquid flows out; a first communication passage that communicates the supply chamber and the pressure chamber; a second communication passage provided coaxially with the first communication passage and communicating between the supply chamber and the pressure chamber; an opening / closing unit including a shaft portion that is inserted into the first communication passage and the second communication passage and moves in response to a displacement of the flexible portion, and a valve portion that is connected to the shaft portion and is capable of opening and closing the first communication passage; a first seal portion provided on an inner periphery of the second communication passage and configured to seal between the second communication passage and an outer periphery of the shaft portion; a pressure applying section that applies pressure to the flexible section in a first direction in which the volume of the pressure chamber decreases; Equipped with A positive pressure adjustment mechanism characterized in that the first seal portion has an arm portion that approaches the outer periphery of the shaft portion as it extends in the first direction.

4. 4. The positive pressure adjustment mechanism according to claim 1, wherein the valve portion is configured to close an opening of the first communication passage on the pressure chamber side.

5. The valve portion is a second seal portion that provides a seal between an inner periphery of the first communication passage and an outer periphery of the shaft portion; a flow passage provided on an inner periphery of the first communication passage; having the shaft portion and the second seal portion are movable relative to an inner periphery of the first communication passage, The flow path is When the second seal portion is in a closed position, the supply chamber and the pressure chamber are not communicated with each other; 4. The positive pressure adjustment mechanism according to claim 1, wherein when the second seal portion is in an open position, the supply chamber and the pressure chamber communicate with each other.

6. The positive pressure adjustment mechanism according to claim 5, characterized in that the second seal portion is provided on the outer periphery of the shaft portion and has an arm portion that approaches the inner periphery of the first communication passage as it extends in the direction opposite to the first direction.

7. The valve portion is a second seal portion that provides a seal between an inner periphery of the first communication passage and an outer periphery of the shaft portion; A flow path provided in the shaft portion; having the shaft portion is movable relative to the second seal portion and the first communication passage, The flow path is When the shaft portion is in a closed position, the supply chamber and the pressure chamber are not communicated with each other; 4. The positive pressure adjustment mechanism according to claim 1, wherein when the shaft portion is in an open position, the supply chamber and the pressure chamber are in communication with each other.

8. The positive pressure adjustment mechanism according to claim 7 , wherein the second seal portion has an arm portion that is provided on an inner periphery of the first communication passage and approaches an outer periphery of the shaft portion as it extends in a direction opposite to the first direction.

9. a liquid ejection head capable of ejecting the liquid; a positive pressure flow path for supplying the liquid to the liquid ejection head; a positive pressure adjustment mechanism according to any one of claims 1 to 3 provided in the positive pressure flow path; A liquid ejection device comprising:

10. a liquid ejection head capable of ejecting the liquid; a positive pressure flow path for supplying the liquid to the liquid ejection head; a negative pressure flow path for recovering the liquid from the liquid ejection head; a positive pressure adjustment mechanism according to any one of claims 1 to 3 provided in the positive pressure flow path; a negative pressure adjustment mechanism provided in the negative pressure flow path and configured to adjust the negative pressure on the liquid ejection head side; A liquid ejection device comprising:

11. a first tank connected to the positive pressure flow path and capable of storing the liquid to be supplied to the liquid ejection head; a second tank connected to the negative pressure flow path and capable of storing the liquid recovered from the liquid ejection head; a connection flow path connecting the second tank and the first tank; a liquid delivery unit that delivers the liquid from the second tank to the first tank through the connection flow path; a pressure pump capable of pressurizing the inside of the first tank; a pressure reducing pump capable of reducing the pressure inside the second tank; The liquid ejection device according to claim 10, further comprising:

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