Positive pressure adjustment mechanism and liquid discharge device

Abstract

To provide a positive pressure adjustment mechanism that can suppress decrease in pressure acting on the inside of a pressure chamber, and a liquid discharge device.SOLUTION: A positive pressure adjustment mechanism comprises: a supply chamber 54 having a first inflow port 62 into which liquid flows; a pressure chamber 55 having a first flexible part 63 formed of a flexible member and has a first outflow port 64 which is formed at a downstream of the supply chamber 54 and from which liquid flows out; a first communication path 56 communicating the supply chamber 54 with the pressure chamber 55; a first regulating part 57 that has a first shaft part 66 which is inserted into the first communication path 56 and 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 arranged in the supply chamber 54, and can regulate flowing of liquid from the supply chamber 54 toward the pressure chamber 55; a first energizing member 58 that energizes the first regulating part 57 in a direction of regulating the flowing of liquid; a pressing part 59 that can press the first flexible part 63 in a direction in which the volume of the pressure chamber 55 reduces; and a pressure-loss increase suppressing part 60 that suppresses an increase in pressure loss caused by the first regulating part 57.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, as disclosed in Patent Document 1, there is a liquid ejection device that prints by ejecting liquid from a liquid ejection head. The liquid ejection device includes a supply flow path, which is an example of a positive pressure flow path, and a positive pressure adjustment unit, which is an example of a positive pressure adjustment mechanism. The supply flow path supplies liquid to the liquid ejection head. The positive pressure adjustment unit is provided in the supply flow path. The positive pressure adjustment unit includes an adjustment on-off valve, which is an example of a regulating unit that inhibits the flow of liquid from a liquid inflow unit, which is an example of a supply chamber, to a liquid outflow unit, which is an example of a pressure chamber. The adjustment on-off valve opens when the pressure in the liquid outflow unit falls below a predetermined positive pressure, allowing liquid to flow from the liquid inflow unit to the liquid outflow unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-116599 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the positive pressure regulator of Patent Document 1, when the pressure in the liquid inlet increases, the regulator on-off valve receives a force in a closing direction. Therefore, in the positive pressure regulator, the pressure loss of the liquid flowing from the liquid inlet to the liquid outlet is likely to increase. If the pressure loss increases, there is a risk that the liquid will not flow sufficiently from the liquid inlet to the liquid outlet even if the pressure in the liquid outlet decreases. [Means for solving the problem]

[0005] A positive pressure adjustment mechanism that solves the above problem includes a supply chamber having an inlet through which liquid flows in, a pressure chamber having a first flexible part formed by a flexible member, located downstream of the supply chamber and having an outlet through which the liquid flows out, a communication passage that connects the supply chamber to the pressure chamber, an axis part that is inserted into the communication passage and moves in accordance with the displacement of the first flexible part, and a valve part that is connected to the axis part and is disposed in the supply chamber, and is equipped with a regulating part that can regulate the flow of the liquid from the supply chamber to the pressure chamber, a biasing member that biases the regulating part in a direction that regulates the flow of the liquid, a pressing part that can press the first flexible part in a direction that reduces the volume of the pressure chamber, and a pressure loss increase suppression part that suppresses an increase in pressure loss due to the regulating part.

[0006] 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.

[0007] 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]

[0008] [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 schematic diagram of a negative pressure adjustment mechanism included in the liquid ejection device. [Figure 4] FIG. 4 is a schematic diagram of a first modified example of the positive pressure adjustment mechanism. [Diagram 5] FIG. 5 is a schematic diagram of a second modified example of the positive pressure adjustment mechanism. [Figure 6]FIG. 6 is a schematic diagram of a third 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

[0009] [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.

[0010] <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.

[0011] 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.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] The liquid flow mechanism 21 may include a liquid delivery section 45 , a pressurizing section 46 , a depressurizing section 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.

[0029] The pressurizing unit 46 is capable of pressurizing the inside of the first tank 25. For example, the pressurizing unit 46 may pressurize the inside of the first tank 25 by sending air into the first tank 25. When the pressurizing unit 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.

[0030] The pressure reducing section 47 is capable of reducing the pressure inside the second tank 26. For example, the pressure reducing section 47 may reduce the pressure inside the second tank 26 by drawing air out of the second tank 26. The pressure reducing section 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.

[0031] When the pressure reducing unit 47 reduces the pressure inside the second tank 26, liquid flows into the second tank 26. For example, when the pressure reducing unit 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 pressure reducing unit 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 pressure reducing unit 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] <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 first communication passage 56 which is an example of a communication passage, a first regulating portion 57 which is an example of a regulating portion, a first biasing member 58 which is an example of a biasing member, a pressing portion 59, and a pressure loss increase suppression portion 60.

[0036] 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. 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.

[0037] The first communication passage 56 communicates the supply chamber 54 and the pressure chamber 55 with each other. The first restricting portion 57 is inserted into the first communication passage 56. The first restricting portion 57 may be inserted into the first communication passage 56 from the supply chamber 54 side. The first restricting portion 57 is capable of restricting the flow of liquid from the supply chamber 54 to the pressure chamber 55. The first restricting portion 57 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 shaft portion 66 and the first valve portion 67 may be configured as a single unit.

[0038] 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 56. At least a portion of the first shaft portion 66 is disposed in the pressure chamber 55. The tip of the first shaft portion 66 is capable of contacting the first flexible portion 63. The first shaft portion 66 moves in accordance with the displacement of the first flexible portion 63.

[0039] The first valve portion 67 is connected to the first shaft portion 66. The first valve portion 67 is disposed in the supply chamber 54. The first valve portion 67 may be frustum-shaped. The first valve portion 67 has an inclined portion 69 that is inclined so that the outer periphery of the first valve portion 67 becomes thinner as it approaches the pressure chamber 55. The minimum diameter of the first valve portion 67 is smaller than the inner diameter of the first communication passage 56. The maximum diameter of the first valve portion 67 is larger than the inner diameter of the first communication passage 56. The outer periphery of the first valve portion 67 is capable of contacting the inner periphery of the first communication passage 56.

[0040] The pressure loss increase suppression portion 60 suppresses an increase in pressure loss caused by the first restriction portion 57. The pressure loss increase suppression portion 60 may include an inclined portion 69. The first biasing member 58 is provided in the supply chamber 54. The first biasing member 58 biases the first restriction portion 57 in a direction that restricts the flow of liquid. Biasing refers to pushing back an object when a force is applied to the object. The first biasing member 58 presses the first valve portion 67 toward the first communication passage 56, thereby causing the first valve portion 67 to close the first communication passage 56. The first biasing member 58 is, for example, a spring.

[0041] The pressing portion 59 is provided outside the pressure chamber 55. The pressing portion 59 is capable of pressing the first flexible portion 63 in a direction in which the volume of the pressure chamber 55 decreases. The pressing portion 59 presses the first restricting portion 57 via the first flexible portion 63. The pressing portion 59 is, for example, a spring.

[0042] <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.

[0043] When the pressure inside the pressure chamber 55 increases, the force with which the liquid inside the pressure chamber 55 presses against the first flexible portion 63 increases. When the pressure inside the supply chamber 54 increases, the force with which the liquid inside the supply chamber 54 presses the first restricting portion 57 towards the first flexible portion 63 increases.

[0044] When the sum of the force of the liquid in the pressure chamber 55 pressing the first flexible portion 63 and the force of the first restricting portion 57 pressing the first flexible portion 63 overcomes the force of the pressing portion 59 pressing the first flexible portion 63, the first flexible portion 63 deforms so as to increase the volume of the pressure chamber 55. As the first flexible portion 63 deforms, the first restricting portion 57 moves in a direction in which the first valve portion 67 approaches the first communication passage 56.

[0045] The first valve portion 67 has an inclined portion 69. Therefore, when the first valve portion 67 moves in a direction approaching the first communication passage 56, the gap between the first valve portion 67 and the first communication passage 56 gradually becomes smaller. The pressure loss of the liquid flowing between the first valve portion 67 and the first communication passage 56 gradually increases.

[0046] When the liquid flows out of the pressure chamber 55 and the pressure inside the pressure chamber 55 drops, the force with which the liquid inside the pressure chamber 55 presses the first flexible portion 63 weakens. When the pressure of the liquid in the supply chamber 54 decreases, the force with which the liquid in the supply chamber 54 presses the first restricting portion 57 towards the first flexible portion 63 weakens.

[0047] When the sum of the force of the liquid in the pressure chamber 55 pressing the first flexible portion 63 and the force of the first restricting portion 57 pressing the first flexible portion 63 is overcome by the force of the pressing portion 59 pressing the first flexible portion 63, the first flexible portion 63 deforms so as to reduce the volume of the pressure chamber 55. When the first restricting portion 57 is pressed by the first flexible portion 63, the first valve portion 67 moves in a direction away from the first communication passage 56. When the first valve portion 67 moves in a direction away from the first communication passage 56, the gap between the first valve portion 67 and the first communication passage 56 gradually becomes larger.

[0048] <Negative pressure adjustment mechanism> As shown in FIG. 3, the negative pressure adjustment mechanism 52 may include an upstream chamber 71, a downstream chamber 72, a second communication passage 73, a second restriction portion 74, a first seal portion 75, and a second biasing member .

[0049] 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 third flexible portion 79. The third 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.

[0050] The second communication passage 73 communicates the upstream chamber 71 and the downstream chamber 72 with each other. The second regulating portion 74 is provided in the upstream chamber 71. The second regulating portion 74 is capable of regulating the flow of liquid from the upstream chamber 71 to the downstream chamber 72. The second regulating 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.

[0051] 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 third flexible portion 79. The second restricting portion 74 moves in accordance with the displacement of the third flexible portion 79.

[0052] 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 second communication passage 73.

[0053] The first seal portion 75 may be provided in the upstream chamber 71. The first seal portion 75 may be provided around the second communication passage 73. The first seal portion 75 seals between the second regulating portion 74 and the inner surface of the upstream chamber 71. The second regulating portion 74 closes the second communication passage 73 as a result of the second valve portion 83 coming into close contact with the first seal portion 75.

[0054] The second biasing member 76 is provided in the downstream chamber 72. A portion of the second biasing member 76 is inserted into the second communication passage 73. The second biasing member 76 presses the second restricting portion 74 in a direction away from the second communication passage 73. The second biasing member 76 is, for example, a spring.

[0055] <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.

[0056] When the negative pressure in the upstream chamber 71 decreases, the force with which the liquid in the upstream chamber 71 pulls the third flexible portion 79 weakens. When the force with which the liquid in the upstream chamber 71 pulls the third flexible portion 79 becomes weaker than the force with which the second biasing member 76 presses the third flexible portion 79 via the second restricting portion 74, the second restricting portion 74 opens the second 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 second communication passage 73 is opened, the negative pressure in the upstream chamber 71 increases.

[0057] When the negative pressure in the upstream chamber 71 increases, the force with which the liquid in the upstream chamber 71 attracts the third flexible portion 79 increases. When the force with which the liquid in the upstream chamber 71 attracts the third flexible portion 79 becomes stronger than the force with which the second biasing member 76 presses the third flexible portion 79 via the second restricting portion 74, the second restricting portion 74 closes the second communication passage 73.

[0058] <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.

[0059] 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 .

[0060] <Effects of the embodiment> The effects of this embodiment will be described. (1-1) Pressure loss increase suppression portion 60 suppresses an increase in pressure loss caused by first restriction portion 57. Therefore, even if the pressure in supply chamber 54 increases, a decrease in the pressure acting on pressure chamber 55 can be suppressed.

[0061] (1-2) The pressure loss increase suppression portion 60 includes an inclined portion 69. The inclined portion 69 is provided on the outer periphery of the first valve portion 67. Therefore, an increase in pressure loss can be suppressed with a simple configuration. (1-3) The outer periphery of the first valve portion 67 can come into contact with the inner periphery of the first communication passage 56. Therefore, the first valve portion 67 can close the first communication passage 56.

[0062] [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.

[0063] <First change example> 4, the first valve portion 67 may be narrower than the first communication passage 56. In other words, the diameter of the first communication passage 56 may be larger than the diameter of the first valve portion 67. The first valve portion 67 may be inserted into the first communication passage 56. The shape of the first valve portion 67 is not limited to a truncated cone shape, and may be, for example, a truncated pyramid shape or an elliptical truncated cone shape.

[0064] <Effects of the first modification> The first valve portion 67 is narrower than the first communication passage 56. Therefore, even when the first valve portion 67 is inserted into the first communication passage 56, a gap can be formed between the first valve portion 67 and the first communication passage 56.

[0065] <Second modification example> 5, pressing portion 59 may have a pressurized chamber 85 and a pressurized flow path 86. Positive pressure adjustment mechanism 51 may have a second seal portion 88. The second seal portion 88 may be provided in supply chamber 54. The second seal portion 88 may be provided around first communication passage 56. The second seal portion 88 seals between first restriction portion 57 and the inner surface of supply chamber 54. The first restriction portion 57 closes first communication passage 56 by the first valve portion 67 coming into close contact with the second seal portion 88.

[0066] The pressure loss increase suppression unit 60 includes a pressurized flow path 86. The pressurized chamber 85 is located on the opposite side of the first flexible portion 63 from the pressure chamber 55 side. The pressure chamber 55 and the pressurized chamber 85 are separated by the first flexible portion 63. The pressurized flow path 86 communicates the pressurized chamber 85 and the supply chamber 54. The pressurized flow path 86 may be connected to a positive pressure flow path 42 between the first tank 25 and the supply chamber 54. The pressurized chamber 85 may communicate with the supply chamber 54 via the pressurized flow path 86 and the positive pressure flow path 42. The pressure in the pressurized chamber 85 becomes approximately the same as the pressure in the supply chamber 54. In the first restricting portion 57, the area of ​​a portion receiving a force from the liquid in the supply chamber 54 in a direction pushing the first restricting portion 57 may be approximately the same as the area of ​​the first flexible portion 63 receiving a force from the liquid in the pressurized chamber 85.

[0067] <Operation of the second modified example> When the pressure in supply chamber 54 increases, the force with which the liquid in supply chamber 54 presses first restricting portion 57 toward first flexible portion 63 increases, and the force with which the liquid in pressurizing chamber 85 presses first flexible portion 63 increases. This reduces the movement of first valve portion 67 in the direction approaching first communication passage 56, thereby reducing fluctuations in pressure loss of the liquid passing through first communication passage 56.

[0068] <Effects of the second amendment> Pressure loss increase suppression section 60 includes a pressurized flow path 86. Pressurized flow path 86 communicates between pressurized chamber 85 and supply chamber 54. Therefore, the pressure of the liquid in supply chamber 54 pressing first restricting section 57 is offset by the pressure of pressurized chamber 85 pressing first restricting section 57 via first flexible section 63. Therefore, an increase in pressure loss can be suppressed with a simple configuration.

[0069] <Third modification example> 6, positive pressure adjustment mechanism 51 may include a force reduction section 90. Pressure loss increase suppression section 60 may include force reduction section 90. By receiving the pressure in supply chamber 54, force reduction section 90 reduces the force in the direction restricting the flow of liquid to first restriction section 57. Force reduction section 90 may have a second flexible section 91 formed by a flexible member.

[0070] The second flexible portion 91 may be provided at a position that separates the inside of the supply chamber 54 from the outside. Atmospheric pressure acts on the outer surface of the second flexible portion 91. The position at which the second flexible portion 91 is provided is also a position at which the first biasing member 58 is sandwiched between the second flexible portion 91 and the first restricting portion 57. One end of the first biasing member 58 is supported by the first restricting portion 57, and the other end is supported by the second flexible portion 91. The second flexible portion 91, the first biasing member 58, the first valve portion 67, the second seal portion 88, and the first communication passage 56 are aligned in a row.

[0071] <Operation of the third modified example> When the pressure inside supply chamber 54 increases, second flexible portion 91 deforms so as to increase the volume of supply chamber 54. This causes the spring constituting first biasing member 58 to stretch, weakening the force with which first biasing member 58 presses first restricting portion 57. This reduces the movement of first valve portion 67 in a direction approaching first communication passage 56, reducing fluctuations in pressure loss of the liquid passing through first communication passage 56.

[0072] <Effects of the Third Amendment> Pressure loss increase suppression section 60 includes a force reduction section 90. Force reduction section 90 reduces the force on first regulating section 57 by receiving the pressure within supply chamber 54. Therefore, the pressure within supply chamber 54 can be used to suppress an increase in pressure loss caused by first regulating section 57.

[0073] Second flexible portion 91 separates the inside of supply chamber 54 from the outside. Second flexible portion 91 sandwiches first biasing member 58 between second flexible portion 91 and first restricting portion 57. Therefore, second flexible portion 91 is deformed by the pressure difference between the pressure inside supply chamber 54 and atmospheric pressure, and can adjust the force with which first biasing member 58 biases first restricting portion 57.

[0074] <Fourth modified example> 7, the force reducer 90 may have a third seal portion 93, which is an example of a seal portion. The first inlet 62 is provided between the third seal portion 93 and the first communication passage 56. The third seal portion 93 is fixed to the first restricting portion 57. The third seal portion 93 is movable together with the first restricting portion 57.

[0075] The third seal portion 93 seals between the first restricting portion 57 and the inner surface of the supply chamber 54. The inner surface of the supply chamber 54 may include an opening surface 54a, a support surface 54b, and a wall surface 54c. The opening surface 54a is a surface where the first communication passage 56 opens. The support surface 54b is a surface that supports the first biasing member 58. The support surface 54b may have an air vent hole 95 that opens the supply chamber 54 to the atmosphere. The wall surface 54c is a surface between the opening surface 54a and the support surface 54b. The third seal portion 93 seals between the first restricting portion 57 and the wall surface 54c. The surface of the third seal portion 93 on the first communication passage 56 side receives the pressure of the liquid supplied to the supply chamber 54. The surface of the third seal portion 93 opposite to the first communication passage 56 receives atmospheric pressure.

[0076] <Operation of the Fourth Modification> When the pressure of the liquid in supply chamber 54 increases, third seal portion 93 receives a force in a direction that increases the portion of supply chamber 54 that contains liquid. Third seal portion 93 is fixed to first restricting portion 57. Therefore, when the pressure in supply chamber 54 increases, first restricting portion 57 and third seal portion 93 receive a force in a direction that moves first valve portion 67 away from first communication passage 56. In other words, even if the pressure of the liquid in supply chamber 54 increases, an increase in the force pressing first restricting portion 57 in a direction that blocks first communication passage 56 is suppressed.

[0077] <Effects of the Fourth Amendment> The third seal portion 93 seals between the first restricting portion 57 and the inner surface of the supply chamber 54. The third seal portion 93 is fixed to the first restricting portion 57. Since the first inlet 62 is provided between the third seal portion 93 and the first communication passage 56, when liquid flows into the supply chamber 54 and the pressure of the liquid in the supply chamber 54 increases, the third seal portion 93 and the first restricting portion 57 receive a force in a direction away from the first communication passage 56. Therefore, an increase in pressure loss can be suppressed with a simple configuration.

[0078] <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.

[0079] The positive pressure adjustment mechanism 51 may be provided in a flow path between the pressurizing unit 46 and the first tank 25. The flow path connects the pressurizing unit 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 unit 46 and supply it to the first tank 25.

[0080] The negative pressure adjustment mechanism 52 may be provided in a flow path between the pressure reduction unit 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 pressure reduction unit 47. The negative pressure adjustment mechanism 52 may adjust the negative pressure by the pressure reduction unit 47 and apply it to the second tank 26.

[0081] <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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] <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.

[0086] 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.

[0087] <Example of change No. 8> 11, the pressurizing unit 46 may be provided in the positive pressure flow path 42. The pressurizing unit 46 may be provided between the first tank 25 and the positive pressure adjustment mechanism 51. The pressurizing unit 46 sends the liquid in the first tank 25 towards the liquid ejection head 12.

[0088] The pressure reducing unit 47 may be provided in the negative pressure flow path 43. The pressure reducing unit 47 may be provided between the negative pressure adjustment mechanism 52 and the second tank . The pressure reducing unit 47 sends liquid from the liquid ejection head 12 toward the second tank .

[0089] <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 the liquid supply source 22. A pressurizing unit 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.

[0090] <10th change example> As shown in FIG. 13, the positive pressure adjustment mechanism 51 may be provided in the flow path between the pressurizing unit 46 and the liquid supply source 22.

[0091] <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.

[0092] <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 .

[0093] <13th Change Example> 16, the pressurizing unit 46 may be provided in the positive pressure flow path 42. The pressurizing unit 46 may be provided between the liquid supply source 22 and the positive pressure adjustment mechanism 51.

[0094] <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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] The negative pressure flow path 43 may connect the liquid ejection head 12 and the first tank 25 . 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.

[0099] [Definition] The term "at least one" as used herein means "one or more" of the desired options. As an example, the term "at least one" as used herein means "only one option" or "both of two options" if the number of options is two. As another example, the term "at least one" as used herein means "only one option", "any combination of two options", or "any combination of three or more options" if the number of options is three or more.

[0100] [Note] The technical ideas and effects obtained from the above-described embodiment and modified examples will be described below.

[0101] (A) A positive pressure adjustment mechanism has a supply chamber having an inlet through which liquid flows in, a pressure chamber having a first flexible part formed by a flexible member, located downstream of the supply chamber and having an outlet through which the liquid flows out, a communicating passage connecting the supply chamber and the pressure chamber, an axis part inserted into the communicating passage and moving in response to displacement of the first flexible part, and a valve part connected to the axis part and disposed in the supply chamber, and is equipped with a regulating part capable of regulating the flow of the liquid from the supply chamber to the pressure chamber, a biasing member that biases the regulating part in a direction to regulate the flow of the liquid, a pressing part that can press the first flexible part in a direction that reduces the volume of the pressure chamber, and a pressure loss increase suppression part that suppresses an increase in pressure loss due to the regulating part.

[0102] According to this configuration, the pressure loss increase suppression portion suppresses an increase in pressure loss caused by the restriction portion, and therefore, even if the pressure in the supply chamber increases, a decrease in the pressure acting on the pressure chamber can be suppressed.

[0103] (B) In the positive pressure adjustment mechanism described in (A), the valve portion has an inclined portion such that the outer periphery of the valve portion becomes thinner as it approaches the pressure chamber, and the pressure loss increase suppression portion may include the inclined portion.

[0104] According to this configuration, the pressure loss increase suppression portion includes the inclined portion. The inclined portion is provided on the outer periphery of the valve portion. Therefore, an increase in pressure loss can be suppressed with a simple configuration. In the positive pressure adjustment mechanism described in (C) and (B), the valve portion may be configured so that an outer periphery of the valve portion is capable of contacting an inner periphery of the communication passage.

[0105] According to this configuration, the outer periphery of the valve portion can come into contact with the inner periphery of the communication passage, so that the communication passage can be closed by the valve portion. In the positive pressure adjustment mechanism described in (D) and (B), the valve portion may be narrower than the communication passage and may be inserted into the communication passage.

[0106] According to this configuration, the valve portion is thinner than the communication passage, so that even when the valve portion is inserted into the communication passage, a gap can be formed between the valve portion and the communication passage. (E) In the positive pressure adjustment mechanism described in (A), the pressing portion has a pressurized chamber on the opposite side of the pressure chamber side of the first flexible portion, and a pressurized flow path connecting the pressurized chamber and the supply chamber, and the pressure loss increase suppression portion may include the pressurized flow path.

[0107] According to this configuration, the pressure loss increase suppression portion includes a pressurized flow path. The pressurized flow path communicates between the pressurized chamber and the supply chamber. Therefore, the pressure of the liquid in the supply chamber pressing against the restriction portion is offset by the pressure of the pressurized chamber pressing against the restriction portion via the first flexible portion. Therefore, an increase in pressure loss can be suppressed with a simple configuration.

[0108] (F) The positive pressure adjustment mechanism described in (A) may further include a force reduction section that reduces the force in the direction of regulating the flow of the liquid relative to the regulating section by receiving pressure within the supply chamber, and the pressure loss increase suppression section may include the force reduction section.

[0109] According to this configuration, the pressure loss increase suppression portion includes the force reduction portion. The force reduction portion receives the pressure in the supply chamber to reduce the force acting on the restriction portion. Therefore, the pressure loss increase caused by the restriction portion can be suppressed by utilizing the pressure in the supply chamber.

[0110] In the positive pressure adjustment mechanism described in (G) and (F), the force reduction portion has a second flexible portion formed by a flexible member, and the second flexible portion may be provided at a position that separates the interior of the supply chamber from the outside and at a position that sandwiches the biasing member between it and the regulating portion.

[0111] According to this configuration, the second flexible portion separates the inside of the supply chamber from the outside. The second flexible portion sandwiches the urging member between the second flexible portion and the restricting portion. Therefore, the second flexible portion deforms due to the pressure difference between the pressure in the supply chamber and atmospheric pressure, and the force with which the urging member urges the restricting portion can be adjusted.

[0112] In the positive pressure adjustment mechanism described in (H)(F), the force reduction portion has a sealing portion fixed to the regulating portion, the sealing portion seals the gap between the regulating portion and the inner surface of the supply chamber, and the inlet may be provided between the sealing portion and the communicating passage.

[0113] According to this configuration, the seal portion seals the gap between the restriction portion and the inner surface of the supply chamber. The seal portion is fixed to the restriction portion. Since the inlet is provided between the seal portion and the communication passage, when liquid flows into the supply chamber and the pressure of the liquid in the supply chamber increases, the seal portion and the restriction portion are subjected to a force in a direction away from the communication passage. Therefore, an increase in pressure loss can be suppressed with a simple configuration.

[0114] (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.

[0115] According to this configuration, the positive pressure adjustment mechanism is provided in the positive pressure flow path, which makes it possible to suppress a decrease in the pressure of the liquid supplied to the liquid ejection head. (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 described in (A) to (H) 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.

[0116] According to this configuration, it is possible to achieve the same effects as those of the above-mentioned liquid ejection device. The liquid ejection device described in (K) and (J) 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 connection 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 connection flow path, a pressurization unit that can pressurize the first tank, and a pressure reduction unit that can reduce the pressure in the second tank.

[0117] 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]

[0118] 11...liquid ejection device, 12...liquid ejection head, 13...nozzle, 14...nozzle surface, 15...inlet path, 16...common liquid chamber, 17...individual liquid chamber, 18...filter, 19...outlet path, 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 chamber, 32...liquid supply flow path, 33...moisture supply flow path, 34... Liquid 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 section, 47...pressurizing section, 48...first atmosphere release valve, 49...second atmosphere release valve, 51...positive pressure adjustment mechanism, 52...negative pressure adjustment mechanism, 54...supply chamber, 54a...opening surface, 54b...support surface, 54c...wall surface, 55...pressure chamber, 56...connecting A first communication passage which is an example of a passage, 57...a first regulating portion which is an example of a regulating portion, 58...a first biasing member which is an example of a biasing member, 59...a pressing portion, 60...a pressure loss increase suppressing portion, 62...a first inlet which is an example of an inlet, 63...a first flexible portion, 64...a first outlet which is an example of an outlet, 66...a first shaft portion which is an example of a shaft portion, 67...a first valve portion which is an example of a valve portion, 69...an inclined portion, 71...an upstream chamber, 72...a downstream Chamber, 73...second communication passage, 74...second regulating portion, 75...first seal portion, 76...second biasing member, 78...second outlet, 79...third flexible portion, 80...second inlet, 82...second shaft portion, 83...second valve portion, 85...pressurization chamber, 86...pressurization flow path, 88...second seal portion, 90...force reduction portion, 91...second flexible portion, 93...third seal portion which is an example of a seal portion, 95...atmospheric vent hole, 97...opening / closing valve, M1...medium.

Claims

1. a supply chamber having an inlet through which liquid flows; a pressure chamber having a first flexible portion formed of a flexible member, the pressure chamber being disposed downstream of the supply chamber and having an outlet through which the liquid flows out; a communication passage that communicates the supply chamber and the pressure chamber; a restricting portion including: a shaft portion that is inserted into the communication passage and moves following the displacement of the first flexible portion; and a valve portion that is connected to the shaft portion and is disposed in the supply chamber, the restricting portion being capable of restricting a flow of the liquid from the supply chamber toward the pressure chamber; a biasing member that biases the regulating portion in a direction that regulates the flow of the liquid; a pressing portion capable of pressing the first flexible portion in a direction in which the volume of the pressure chamber decreases; a pressure loss increase suppression unit that suppresses an increase in pressure loss due to the regulating unit; A positive pressure adjustment mechanism comprising:

2. the valve portion has an inclined portion that is inclined so that an outer periphery of the valve portion becomes thinner as it approaches the pressure chamber, The positive pressure adjusting mechanism according to claim 1 , wherein the pressure loss increase suppressing portion includes the inclined portion.

3. 3. The positive pressure adjusting mechanism according to claim 2, wherein an outer periphery of the valve portion is capable of coming into contact with an inner periphery of the communication passage.

4. 3. The positive pressure adjusting mechanism according to claim 2, wherein the valve portion is narrower than the communication passage and is inserted into the communication passage.

5. The pressing portion is a pressure chamber on an opposite side of the first flexible portion from the pressure chamber; a pressurized flow passage communicating the pressurized chamber and the supply chamber; having The positive pressure adjustment mechanism according to claim 1 , wherein the pressure loss increase suppression portion includes the pressurized flow path.

6. a force reducing portion configured to reduce a force acting in a direction restricting the flow of the liquid against the restricting portion by receiving a pressure in the supply chamber, The positive pressure adjustment mechanism according to claim 1 , wherein the pressure loss increase suppression portion includes the force reduction portion.

7. The force reducing portion has a second flexible portion formed by a flexible member, The positive pressure adjustment mechanism according to claim 6 , wherein the second flexible portion is provided at a position that separates the inside of the supply chamber from the outside and at a position that sandwiches the biasing member between the second flexible portion and the restricting portion.

8. the force reducer has a seal portion fixed to the restricting portion, the seal portion seals between the restriction portion and an inner surface of the supply chamber, The positive pressure adjustment mechanism according to claim 6 , wherein the inlet is provided between the seal portion and the communication passage.

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 8 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 8 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 pressurizing unit capable of pressurizing the inside of the first tank; a pressure reducing section capable of reducing the pressure inside the second tank; The liquid ejection device according to claim 10, further comprising:

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