Liquid spraying device

Abstract

To provide a liquid ejection apparatus capable of reducing the possibility of foreign substances generated at an air-liquid interface flowing downstream of a liquid storage part.SOLUTION: The liquid ejecting apparatus includes an ejecting part 12 for ejecting a liquid onto a medium; a supply flow path 21 for supplying the liquid to the ejecting part 12, a liquid storage part 22 which is coupled to the supply flow path 21 and stores the liquid, and in which an air-liquid interface 36 is formed between the liquid and air, a first filter 23 disposed below the air-liquid interface 36 and for separating the supply flow path 21 and the liquid storage part 22, an adjustment mechanism 14 for raising the level of the air-liquid interface 36 in the liquid storage part 22, and a control part 15 for controlling the adjustment mechanism 14.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a liquid ejecting apparatus such as a printer. [Background technology]

[0002] For example, Patent Document 1 discloses a liquid ejection device that is an example of a liquid ejection device that prints by ejecting ink, an example of a liquid, from a liquid ejection head, an example of an ejection unit. The liquid ejection device includes a circulation flow path, an example of a supply flow path, an air bubble chamber, an example of a liquid storage unit, and an air bubble chamber filter, an example of a first filter. The circulation flow path distributes ink from a liquid supply source to the liquid ejection head. The air bubble chamber is provided in the circulation flow path. The air bubble chamber stores air bubbles contained in the ink.

[0003] The liquid in the bubble chamber is prone to generating foreign matter at the gas-liquid interface where it comes into contact with the stored air. The bubble chamber filter is provided between the gas-liquid interface and the flow path. Therefore, the bubble chamber filter captures foreign matter generated at the gas-liquid interface before it flows into the flow path. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-77107 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, the position of the gas-liquid interface in the bubble chamber changes depending on the amount of air stored in the liquid storage section. That is, when there is a lot of air, the gas-liquid interface is located lower than when there is a little air. In particular, when the gas-liquid interface falls below the bubble chamber filter, the bubble chamber filter cannot capture foreign matter generated at the gas-liquid interface, and the foreign matter flows into the supply channel. [Means for solving the problem]

[0006] A liquid injection device that solves the above problem includes an injection unit capable of injecting liquid onto a medium, a supply flow path capable of supplying the liquid to the injection unit, a liquid storage unit connected to the supply flow path and capable of storing the liquid, where an air-liquid interface is formed where the liquid comes into contact with air, a first filter provided below the air-liquid interface and separating the supply flow path from the liquid storage unit, an adjustment mechanism capable of raising the height of the air-liquid interface within the liquid storage unit, and a control unit that controls the adjustment mechanism. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram of an embodiment of a liquid ejection device. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Embodiment] <Liquid injection device> An embodiment of a liquid ejection device will be described below with reference to the drawings. The liquid ejection device is an inkjet printer that prints by ejecting ink, which is an example of a liquid, onto a medium such as paper, fabric, vinyl, plastic parts, or metal parts.

[0009] In the drawings, the liquid ejection device 11 is assumed to be placed on a horizontal plane, with the direction of gravity indicated by the Z axis, and directions along the horizontal plane indicated by the X and Y axes. The X, Y, and Z axes are perpendicular to one another. In the following description, the direction parallel to the Z axis is also referred to as the vertical direction Z, the direction above the vertical direction Z is simply referred to as "upper" or "upper," and the direction below the vertical direction Z is simply referred to as "lower" or "lower."

[0010] Liquid ejection device 11 includes ejection unit 12, supply mechanism 13, adjustment mechanism 14, and control unit 15. Liquid ejection device 11 may also include mounting unit 16. A liquid supply source 17 that stores liquid is removably mounted to mounting unit 16. Liquid supply source 17 may be refillable with liquid. When liquid supply source 17 is refillable, it may be fixed to mounting unit 16.

[0011] The ejection unit 12 has a plurality of nozzles 19. The ejection unit 12 is capable of ejecting liquid onto a medium (not shown). The ejection unit 12 prints on the medium by ejecting liquid from the nozzles 19. The ejection unit 12 may be a serial type that prints by ejecting liquid while moving. The ejection unit 12 may also be a line type that is provided elongated in the width direction of the medium and prints by ejecting liquid onto the medium as it is transported.

[0012] The supply mechanism 13 includes a supply flow path 21, a liquid storage section 22, and a first filter 23. The supply mechanism 13 may also include a second flexible membrane 24, a drive section 25, a second filter 26, a branch section 27, a branch flow path 28, a pump 29, and a liquid level detection sensor 30.

[0013] The upstream end of the supply flow path 21 may be configured with a supply needle 32. The supply needle 32 is provided in the mounting part 16. The supply needle 32 is inserted into the liquid supply source 17 mounted in the mounting part 16, thereby enabling the liquid contained in the liquid supply source 17 to be discharged.

[0014] The supply flow path 21 is capable of supplying liquid to the ejecting unit 12. The supply flow path 21 supplies liquid to the ejecting unit 12 from a liquid supply source 17 attached to the attachment unit 16. The supply flow path 21 may supply liquid by a hydraulic head. In this embodiment, the direction of the liquid flowing through the supply flow path 21 is defined as a liquid sending direction D. The upstream end of the supply flow path 21 in the liquid sending direction D is connected to the liquid supply source 17, and the downstream end of the supply flow path 21 in the liquid sending direction D is connected to the ejecting unit 12.

[0015] The supply flow path 21 may have a supply chamber 34. The supply chamber 34 is located below the liquid storage section 22. The supply chamber 34 is separated from the liquid storage section 22 by the first filter 23. The supply chamber 34 is a space below the first filter 23. The liquid supplied from the liquid supply source 17 passes through the supply chamber 34 and is supplied to the ejection section 12. The liquid in the supply chamber 34 passes through the first filter 23 due to the pressure difference between the inside of the supply chamber 34 and the inside of the liquid storage section 22. That is, the liquid can flow from the supply chamber 34 through the first filter 23 and into the liquid storage section 22. The liquid in the liquid storage section 22 can pass through the first filter 23 and flow into the supply chamber 34.

[0016] The second flexible film 24 is provided below the first filter 23. The second flexible film 24 may form part of the wall surface of the supply chamber 34. For example, the second flexible film 24 may form the bottom of the supply chamber 34. The second flexible film 24 is deformable. The second flexible film 24 may be made of an elastic material such as silicone rubber.

[0017] The drive unit 25 can move the second flexible membrane 24 between a second retracted position shown by a solid line in Fig. 1 and a second advanced position shown by a two-dot chain line in Fig. 1. The second advanced position is a position advanced closer to the first filter 23 than the second retracted position. The drive unit 25 changes the volume of the supply flow path 21 by moving the second flexible membrane 24. Specifically, the drive unit 25 reduces the volume of the supply chamber 34 by pushing the second flexible membrane 24 to move it from the second retracted position to the second advanced position.

[0018] The liquid storage section 22 is connected to the supply flow path 21. The liquid storage section 22 is provided above the supply flow path 21. The liquid storage section 22 is capable of storing liquid. The liquid storage section 22 is capable of collecting air bubbles in the liquid. In this embodiment, the air bubbles collected in the liquid storage section 22 are also referred to as air. In the liquid storage section 22, an air-liquid interface 36 is formed where the liquid and the air come into contact. The air-liquid interface 36 is the upper surface of the stored liquid, and is also referred to as the liquid surface.

[0019] The first filter 23 separates the supply flow path 21 from the liquid storage section 22. The first filter 23 may be provided horizontally or at an angle. In this embodiment, the space below the first filter 23 is the supply chamber 34, and the space above the first filter 23 is the liquid storage section 22. Therefore, when the gas-liquid interface 36 is in the liquid storage section 22, the first filter 23 is provided below the gas-liquid interface 36. At least a portion of the gas-liquid interface 36 in the liquid storage section 22 is aligned in the vertical direction Z with at least a portion of the first filter 23. The liquid storage section 22, the first filter 23, and the supply chamber 34 are aligned in the vertical direction Z.

[0020] Second filter 26 may be provided in supply flow path 21 downstream of liquid storage section 22 in the liquid sending direction D. Second filter 26 may be provided downstream of supply chamber 34 in the liquid sending direction D. Second filter 26 may be provided between supply chamber 34 and branch section 27 in the liquid sending direction D.

[0021] The first filter 23 and the second filter 26 can be, for example, a mesh-like body, a porous body, or a perforated plate with fine through-holes. Mesh-like filters include wire mesh, resin netting, mesh filters, and metal fiber filters. Metal fiber filters include felt filters made from fine stainless steel wires and sintered metal filters made from compressed and sintered fine stainless steel wires. Perforated plate filters include electroformed metal filters, electron beam processed metal filters, and laser beam processed metal filters.

[0022] The first filter 23 and the second filter 26 may be the same filter, or may be different in type and shape. For example, the second filter 26 may have finer mesh than the first filter 23.

[0023] The branch section 27 branches off the branch flow path 28 from the supply flow path 21. That is, the branch flow path 28 is separated from the supply flow path 21 downstream of the liquid storage section 22 in the liquid transfer direction D. The branch flow path 28 branches off downstream of the supply chamber 34 in the liquid transfer direction D. In this embodiment, the side of the branch flow path 28 that branches off from the supply flow path 21 is also referred to as one end side, and the opposite side is also referred to as the other end side. One end side of the branch flow path 28 is connected to the branch section 27. The other end side of the branch flow path 28 is connected to the liquid storage section 22. The branch flow path 28 connects the supply flow path 21 and the liquid storage section 22.

[0024] The pump 29 causes the liquid to flow in the branch flow path 28. The pump 29 causes the liquid to flow in the branch flow path 28 from one end to the other end. The pump 29 sends the liquid sent downstream in the liquid sending direction D from the supply chamber 34 to the liquid storage section 22 through the branch flow path 28. The pump 29 circulates the liquid in the supply chamber 34, the supply flow path 21 between the supply chamber 34 and the branch section 27, the branch flow path 28, and the liquid storage section 22. The liquid circulates while passing through the first filter 23 and the second filter 26.

[0025] The liquid level detection sensor 30 detects that the position of the gas-liquid interface 36 is at a predetermined position above the first filter 23. For example, the liquid level detection sensor 30 may be a contact sensor that detects contact with the liquid. The liquid level detection sensor 30 may include an electrode provided at a predetermined position within the liquid storage section 22. The liquid level detection sensor 30 may detect that the gas-liquid interface 36 has descended to a predetermined position by detecting a resistance that changes between when the liquid is in contact with the electrode and when it is not in contact with the electrode. The predetermined position may be above the position where the branch flow path 28 is connected.

[0026] The adjustment mechanism 14 may include a first flexible membrane 38 , a valve portion 39 , and a suction portion 40 . The first flexible film 38 is deformable. The first flexible film 38 may be provided above the gas-liquid interface 36. The first flexible film 38 may be provided above the liquid level detection sensor 30. The first flexible film 38 may form part of a wall surface of the liquid storage section 22. For example, the first flexible film 38 may form the ceiling of the liquid storage section 22.

[0027] The first flexible membrane 38 is movable between a first retracted position shown by a solid line in Fig. 1 and a first advanced position shown by a two-dot chain line in Fig. 1. The first advanced position is a position advanced closer to the gas-liquid interface 36 than the first retracted position. The first advanced position is a position closer to the first filter 23 than the first retracted position. The first flexible membrane 38 moves in accordance with changes in pressure within the liquid storage section 22. The first flexible membrane 38 may be formed from an elastic material such as silicone rubber.

[0028] The valve unit 39 is provided in the supply flow path 21 upstream of the liquid storage unit 22 in the liquid sending direction D. The valve unit 39 is provided upstream of the supply chamber 34 in the liquid sending direction D. When the valve unit 39 is open, it allows the liquid to flow in the supply flow path 21. When the valve unit 39 is closed, it restricts the flow of the liquid in the supply flow path 21.

[0029] The suction unit 40 may include a cap 42, a discharge flow path 43, a pressure reducing unit 44, and a waste liquid storage unit 45. The waste liquid storage unit 45 may be provided detachably with respect to the liquid ejecting device 11.

[0030] The cap 42 is capable of receiving the liquid discharged from the nozzle 19. The cap 42 may have a lip portion 46. The lip portion 46 is annular and forms an opening in the cap 42.

[0031] The cap 42 may be provided so as to be movable between a capping position (not shown) in which the ejection portion 12 is capped, and a separated position (shown in FIG. 1) in which the ejection portion 12 is opened. When the cap 42 is positioned at the capping position, the lip portion 46 comes into contact with the spray portion 12. When the cap 42 is positioned at the capping position, the opening of the cap 42 is blocked by the spray portion 12, thereby forming a closed space in which the nozzle 19 is open. If the lip portion 46 is formed from, for example, elastically deformable rubber or elastomer, the airtightness of the closed space can be improved. When the cap 42 is positioned at the separated position, the lip portion 46 is separated from the spray portion 12. When the cap 42 is positioned at the separated position, the opening of the cap 42 is open.

[0032] The discharge flow path 43 has an upstream end connected to the cap 42 and a downstream end connected to the waste liquid storage section 45. The discharge flow path 43 may be formed of, for example, a tube that can deform in accordance with the movement of the cap 42. The discharge flow path 43 can discharge the liquid in the cap 42 to the waste liquid storage section 45.

[0033] The pressure reducing unit 44 may be provided in the discharge flow path 43. The pressure reducing unit 44 is, for example, a tube pump. The pressure reducing unit 44 is capable of reducing the pressure in the space inside the cap 42 via the discharge flow path 43.

[0034] The suction unit 40 performs a suction operation by causing the pressure reducing unit 44 to reduce the pressure inside the cap 42 while the cap 42 is positioned in the capping position. When the pressure inside the cap 42 is reduced, liquid is discharged from the nozzle 19 and supplied to the ejection unit 12 from the supply flow path 21. That is, by performing a suction operation, the suction unit 40 sucks the liquid inside the liquid storage unit 22 and causes the liquid inside the liquid storage unit 22 to flow downstream in the liquid transfer direction D. The liquid inside the liquid storage unit 22 flows downstream in the liquid transfer direction D through the first filter 23 and the supply chamber 34.

[0035] The control unit 15 controls the adjustment mechanism 14. The control unit 15 comprehensively controls the driving of each mechanism in the liquid ejection device 11 and controls various operations performed by the liquid ejection device 11. The control unit 15 can be configured as a circuit including: α: one or more processors that execute various processes according to a computer program; β: one or more dedicated hardware circuits that execute at least some of the various processes; or γ: a combination thereof. The hardware circuit is, for example, an application-specific integrated circuit. The processor includes a CPU and memory such as RAM and ROM, and the memory stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any readable medium that can be accessed by a general-purpose or dedicated computer.

[0036] <Operation of the embodiment> The operation of this embodiment will be described. Air bubbles may be mixed into the supply flow path 21. Air bubbles in the supply flow path 21 may be generated, for example, when air enters through the supply needle 32 as the liquid supply source 17 is attached or detached from the supply needle 32. Air bubbles may also be generated, for example, when air dissolved in the liquid turns into a gas. The air bubbles flow through the supply flow path 21 in the liquid sending direction D together with the liquid. The air bubbles sent to the supply chamber 34 pass through the first filter 23 by buoyancy and collect in the liquid storage section 22.

[0037] However, depending on the type of first filter 23 and the size of the bubbles, for example, the bubbles may not pass through first filter 23 and may remain below first filter 23. Control unit 15 may control the driving of drive unit 25 to send the bubbles in supply chamber 34 to liquid storage unit 22.

[0038] Specifically, the drive unit 25 moves the second flexible film 24 in a state in which the gas-liquid interface 36 is above the first filter 23. The drive unit 25 advances the second flexible film 24 from the second retracted position shown by the solid line in Fig. 1 to the second advanced position shown by the two-dot chain line in Fig. 1, thereby reducing the volume of the supply flow path 21. When the second flexible film 24 moves from the second retracted position to the second advanced position, the volume of the supply chamber 34 decreases and the pressure within the supply chamber 34 increases, making it easier for air bubbles within the supply chamber 34 to pass through the first filter 23.

[0039] The air bubbles collected in the liquid storage section 22 become air masses and form a gas-liquid interface 36 with the liquid. In other words, the gas-liquid interface 36 allows the liquid to come into contact with air, making the liquid surface prone to drying. Liquid with a dried surface tends to become locally concentrated, potentially resulting in dispersion breakdown. For example, if the liquid contains a resin component, the resin particles may bond together, resulting in large particles that become foreign matter. Foreign matter formed in this way is difficult to redissolve in the liquid. Therefore, once foreign matter has formed, it tends to remain. However, the first filter 23 is located between the gas-liquid interface 36 and the supply flow path 21. The first filter 23 captures foreign matter, keeping it in the liquid storage section 22.

[0040] The gas-liquid interface 36 in the liquid storage portion 22 moves depending on the amount of air in the liquid storage portion 22. Specifically, the gas-liquid interface 36 drops by the amount of air added. The adjustment mechanism 14 is capable of raising the height of the gas-liquid interface 36 in the liquid storage portion 22. The control unit 15 raises the gas-liquid interface 36 before the liquid storage portion 22 is filled with air. The control unit 15 raises the gas-liquid interface 36 before the gas-liquid interface 36 descends to the first filter 23.

[0041] The control unit 15 of this embodiment controls the adjustment mechanism 14 to raise the gas-liquid interface 36 when the gas-liquid interface 36 has descended to a predetermined position based on detection by the liquid level detection sensor 30. For example, the control unit 15 may determine that the gas-liquid interface 36 has descended to the predetermined position when the liquid level detection sensor 30 switches from a state in which it detects liquid to a state in which it does not detect liquid.

[0042] To raise the gas-liquid interface 36, the control unit 15 first executes a lowering operation. The lowering operation lowers the gas-liquid interface 36 by causing the suction unit 40 to perform a suction operation while the valve unit 39 is closed. During the lowering operation, the pressure inside the liquid storage unit 22 is reduced. Therefore, the first flexible film 38 advances from the first retracted position shown by the solid line in FIG. 1 to the first advanced position shown by the two-dot chain line in FIG. 1 as the first flexible film 38 descends. The first flexible film 38 reduces the volume of the liquid storage unit 22.

[0043] When the gas-liquid interface 36 descends below the first filter 23, the gas-liquid interface 36 is formed in the supply chamber 34. Therefore, the air stored in the liquid storage section 22 is sent downstream in the liquid sending direction D via the supply chamber 34. That is, the air is discharged from the liquid storage section 22, and the pressure in the liquid storage section 22 decreases. Therefore, when the valve unit 39 is opened in a state in which the gas-liquid interface 36 has descended below the first filter 23 by the descending operation, the gas-liquid interface 36 rises to a position higher than the position before the descending operation was performed. The control unit 15 may open the valve unit 39 after stopping the suction operation, or may open the valve unit 39 while the suction operation is continuing.

[0044] <Effects of the embodiment> The effects of this embodiment will be described. (1) The first filter 23 separates the supply flow path 21 from the liquid storage portion 22. The adjustment mechanism 14 can adjust the height of the gas-liquid interface 36 in the liquid storage portion 22. Therefore, by controlling the adjustment mechanism 14, the control portion 15 can adjust the gas-liquid interface 36 so that it is located above the first filter 23. In other words, the first filter 23 can be maintained in a state where it is located below the gas-liquid interface 36, thereby reducing the risk of foreign matter generated at the gas-liquid interface 36 flowing downstream of the liquid storage portion 22.

[0045] (2) The control unit 15 closes the valve unit 39 and performs a suction operation, thereby lowering the gas-liquid interface 36 to below the first filter 23. As a result, the air in the liquid storage unit 22 is sent downstream in the liquid transfer direction D together with the liquid. Therefore, when the valve unit 39 is opened and liquid is supplied from upstream in the liquid transfer direction D, the gas-liquid interface 36 in the liquid storage unit 22 rises from its original position. Therefore, the gas-liquid interface 36 can be raised with a simple configuration.

[0046] (3) First flexible membrane 38 moves from the first retracted position to the first advanced position as it descends, thereby reducing the volume of liquid storage portion 22. Therefore, first flexible membrane 38 can easily lower gas-liquid interface 36 by the downward movement, and can easily raise gas-liquid interface 36 by opening valve portion 39.

[0047] (4) The gas-liquid interface 36 descends, for example, as the amount of air in the liquid storage portion 22 increases. When the gas-liquid interface 36 descends to a predetermined position, the control portion 15 controls the adjustment mechanism 14 to raise the gas-liquid interface 36. The predetermined position is a position above the first filter 23. Therefore, the gas-liquid interface 36 can be positioned above the first filter 23.

[0048] (5) Air bubbles in the supply flow path 21 may remain below the first filter 23 without passing through the first filter 23. In this regard, the drive unit 25 reduces the volume of the supply flow path 21 by advancing the second flexible membrane 24 from the second retracted position to the second advanced position. This increases the pressure within the supply flow path 21, making it easier for air bubbles remaining below the first filter 23 to pass through the first filter 23. Therefore, the air bubbles can be easily collected in the liquid storage unit 22.

[0049] (6) The second filter 26 is provided in the supply flow path 21 downstream of the liquid storage section 22. The second filter 26 has finer mesh than the first filter 23. Therefore, even if foreign matter passes through the first filter 23, the second filter 26 can capture the foreign matter.

[0050] (7) Branch flow path 28 connects supply flow path 21 downstream of liquid storage section 22 to liquid storage section 22. Pump 29 causes the liquid to flow in branch flow path 28. The liquid is sent to supply flow path 21, branch flow path 28, and liquid storage section 22 in that order, and circulates by passing through first filter 23. Therefore, even when a liquid that settles is used, sedimentation can be reduced.

[0051] [Example of change] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0052] The supply mechanism 13 may include a supply pump that sends liquid from the liquid supply source 17 to the ejection part 12. The supply pump may be provided in the supply flow path 21 upstream of the supply chamber 34 in the liquid sending direction D. The supply pump may be provided in the supply flow path 21 downstream of the supply chamber 34 in the liquid sending direction D.

[0053] The pump 29 may be provided in the supply flow path 21 between the first filter 23 and the branching portion 27 in the liquid sending direction D. The liquid ejection device 11 may include a downstream valve provided in the supply flow path 21 or the ejection portion 12 downstream of the branching portion 27 in the liquid sending direction D. The pump 29 may supply the liquid to the nozzle 19 by being driven with the downstream valve open. The pump 29 may cause the liquid to flow from one end side to the other end side of the branching flow path 28 by being driven with the downstream valve closed.

[0054] Branching portion 27 may be provided in ejecting portion 12. Branching flow path 28 may connect ejecting portion 12 and liquid storage portion 22. Pump 29 may circulate the liquid in supply chamber 34, supply flow path 21 downstream of supply chamber 34 in liquid transfer direction D, ejecting portion 12, branching flow path 28, and liquid storage portion 22.

[0055] The mesh size of second filter 26 may be the same as that of first filter 23. The mesh size of second filter 26 may be coarser than that of first filter 23. By making the mesh size of second filter 26 coarser than that of first filter 23, pressure loss can be reduced. Second filter 26 may be provided at an outlet through which liquid flows out from supply chamber 34. Second filter 26 may collect air bubbles, thereby keeping the air bubbles in supply chamber 34 and making it easier for the air bubbles to collect in liquid storage section 22. Second filter 26 may be provided in spray section 12.

[0056] The driving unit 25 may move the first flexible film 38. For example, the driving unit 25 may move the first flexible film 38 from the first advanced position to the first retracted position to reduce the pressure in the liquid storage unit 22, thereby moving the air bubbles in the supply chamber 34 to the liquid storage unit 22.

[0057] The liquid level detection sensor 30 may include a prism provided at a predetermined position, an irradiating unit that irradiates light onto the prism, and a light receiving unit that receives the light refracted by the prism. While the liquid is in contact with the prism, the light diffuses into the liquid. When the gas-liquid interface 36 is positioned below the prism and the prism is exposed from the liquid, the light refracted by the prism reaches the light receiving unit. The liquid level detection sensor 30 may detect the position of the gas-liquid interface 36 from changes in the amount of light received by the light receiving unit.

[0058] The liquid level detection sensor 30 may be a float sensor that detects the position of a float floating on the liquid. The liquid level detection sensor 30 may be an image sensor that detects an image. The liquid level detection sensor 30 may detect the position of the gas-liquid interface 36 by analyzing the image detected by the image sensor.

[0059] The liquid level detection sensor 30 may be a photoelectric sensor including a light-emitting unit that emits light and a light-receiving unit that receives light. The light-emitting unit and the light-receiving unit may be arranged on either side of the liquid storage unit 22. The light-receiving unit may receive light that has passed through the liquid storage unit 22. For example, when the gas-liquid interface 36 is above a predetermined position, the light is blocked by liquid present between the light-emitting unit and the light-receiving unit. The liquid level detection sensor 30 may detect the position of the gas-liquid interface 36 from a change in the amount of light received by the light-receiving unit.

[0060] The suction unit 40 may be used for maintenance of the spray unit 12. The suction unit 40 may perform suction cleaning by performing a suction operation to discharge liquid from the nozzle 19. Suction cleaning is maintenance that discharges liquid with increased viscosity and air bubbles around the nozzle 19.

[0061] At least a portion of the first flexible film 38 may constitute a side wall of the liquid storage section 22. A portion of the first flexible film 38 may be located below the gas-liquid interface 36. The volume of the liquid storage section 22 may not change. The liquid storage section 22 may be formed of a hard material. The liquid storage section 22 may be open to the atmosphere. That is, atmospheric pressure may act on the gas-liquid interface 36. The adjustment mechanism 14 may have, for example, a supply pump provided upstream of the supply chamber 34 in the liquid transfer direction D, and the supply pump may supply liquid to the supply chamber 34 to raise the gas-liquid interface 36 in the liquid storage section 22.

[0062] The adjustment mechanism 14 may have a decompression pump that reduces the pressure inside the liquid storage section 22. The adjustment mechanism 14 may raise the gas-liquid interface 36 by reducing the pressure inside the liquid storage section 22 with the decompression pump.

[0063] A portion of first filter 23 may be located below an inlet through which liquid flows into supply chamber 34. A portion of first filter 23 may be located below an outlet through which liquid flows out of supply chamber 34.

[0064] The liquid storage section 22 may adjust the pressure in the supply flow path 21. When the pressure in the supply flow path 21 changes, the volume of the air in the liquid storage section 22 changes. This makes it possible to mitigate the change in pressure in the supply flow path 21. The liquid storage section 22 may mitigate the change in pressure in the supply flow path 21 by changing the volume through the movement of the first flexible membrane 38.

[0065] The liquid ejection device 11 may be a liquid ejection device that ejects or discharges liquids other than ink. The liquid ejected as minute droplets from the liquid ejection device may be in the form of granules, tears, or strings. The liquid referred to here may be any material that can be ejected from the liquid ejection device. For example, the liquid may be in any liquid phase, including 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 may refer not only to a single state of matter, but also to particles of solid functional materials, such as pigments and metal particles, dissolved, dispersed, or mixed in a solvent. Typical examples of liquids include inks and liquid crystals, as described in the above embodiments. Here, ink encompasses 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 liquid ejection devices include devices that eject liquids containing dispersed or dissolved materials such as electrode materials and color materials used in the manufacture of liquid crystal displays, electroluminescent displays, surface-emitting displays, and color filters. The liquid ejection device may be a device that ejects bioorganic materials used in biochip manufacture, a device used as a precision pipette to eject sample liquids, a textile printing device, a microdispenser, or the like. The liquid ejection device may be a device that injects lubricating oil with pinpoint accuracy onto precision machinery such as watches and cameras, or a device that ejects transparent resin liquids such as ultraviolet-curing resins onto substrates to form micro-hemispherical lenses, optical lenses, etc. used in optical communication elements, etc. The liquid ejection device may also be a device that ejects etching liquids such as acids or alkalis to etch substrates, etc.

[0066] [Note] The technical concepts and effects that can be understood from the above-described embodiment and modified examples will be described below.

[0067] (A) A liquid injection device includes an injection unit capable of injecting a liquid onto a medium, a supply flow path capable of supplying the liquid to the injection unit, a liquid storage unit connected to the supply flow path and capable of storing the liquid, in which an air-liquid interface is formed where the liquid comes into contact with air, a first filter provided below the air-liquid interface and separating the supply flow path from the liquid storage unit, an adjustment mechanism capable of raising the height of the air-liquid interface within the liquid storage unit, and a control unit that controls the adjustment mechanism.

[0068] According to this configuration, the first filter separates the supply flow path from the liquid storage portion. The adjustment mechanism can adjust the height of the gas-liquid interface in the liquid storage portion. Therefore, the control portion can adjust the gas-liquid interface to be located above the first filter by controlling the adjustment mechanism. In other words, the first filter can be maintained below the gas-liquid interface, thereby reducing the risk of foreign matter generated at the gas-liquid interface flowing downstream from the liquid storage portion.

[0069] (B) In a liquid injection device, when the direction of the liquid flowing through the supply flow path is set to the liquid delivery direction, the adjustment mechanism has a valve section provided in the supply flow path upstream of the liquid storage section in the liquid delivery direction, and a suction section that performs a suction operation to suck the liquid in the liquid storage section and flow the liquid downstream in the liquid delivery direction, and the control section may perform a lowering operation to lower the gas-liquid interface by performing the suction operation with the valve section closed, and open the valve section when the gas-liquid interface has been lowered to below the first filter by the lowering operation.

[0070] According to this configuration, the control unit closes the valve unit and performs a suction operation, thereby lowering the gas-liquid interface to below the first filter. As a result, the air in the liquid storage unit is sent downstream in the liquid transfer direction along with the liquid. Therefore, when the valve unit is opened and liquid is supplied from upstream in the liquid transfer direction, the gas-liquid interface in the liquid storage unit rises from its original position. Therefore, the gas-liquid interface can be raised with a simple configuration.

[0071] (C) In the liquid injection device, the adjustment mechanism has a first flexible membrane located above the gas-liquid interface, and the first flexible membrane is movable between a first retracted position and a first advanced position that is advanced toward the gas-liquid interface from the first retracted position, and the volume of the liquid storage section may be reduced by advancing from the first retracted position to the first advanced position in conjunction with the downward movement.

[0072] With this configuration, the first flexible membrane moves from the first retracted position to the first advanced position as it descends, thereby reducing the volume of the liquid storage portion, so that the gas-liquid interface can be easily lowered by the descending operation, and the gas-liquid interface can be easily raised by opening the valve portion.

[0073] (D) The liquid injection device may include a liquid level detection sensor that detects that the position of the gas-liquid interface is at a predetermined position above the first filter, and the control unit may control the adjustment mechanism to raise the gas-liquid interface when the gas-liquid interface descends to the predetermined position based on detection by the liquid level detection sensor.

[0074] The gas-liquid interface descends, for example, as the amount of air in the liquid storage portion increases. With this configuration, when the gas-liquid interface descends to a predetermined position, the control unit controls the adjustment mechanism to raise the gas-liquid interface. The predetermined position is a position above the first filter. Therefore, the gas-liquid interface can be positioned above the first filter.

[0075] (E) The liquid injection device may further include a second flexible membrane located below the first filter, and a drive unit capable of moving the second flexible membrane to a second retracted position and a second advanced position advanced toward the first filter from the second retracted position, and the drive unit may reduce the volume of the supply flow path by advancing the second flexible membrane from the second retracted position to the second advanced position when the gas-liquid interface is above the first filter.

[0076] Air bubbles in the supply flow path may remain below the first filter without passing through it. In this regard, with this configuration, the drive unit reduces the volume of the supply flow path by advancing the second flexible membrane from the second retracted position to the second advanced position. This increases the pressure within the supply flow path, making it easier for air bubbles remaining below the first filter to pass through the first filter. Therefore, air bubbles can be easily collected in the liquid storage section.

[0077] (F) The liquid injection device may further include a second filter provided in the supply flow path downstream of the liquid storage section in the liquid sending direction when the direction of the liquid flowing through the supply flow path is defined as the liquid sending direction, and the second filter may have finer mesh than the first filter.

[0078] According to this configuration, the second filter is provided in the supply flow path downstream of the liquid storage section. The second filter has finer mesh than the first filter. Therefore, even if foreign matter passes through the first filter, the second filter can capture the foreign matter.

[0079] (G) The liquid injection device may further include a branch flow path that separates from the supply flow path downstream of the liquid storage section in the liquid transfer direction when the direction of the liquid flowing through the supply flow path is the liquid transfer direction, and a pump that causes the liquid to flow in the branch flow path, and when the side of the branch flow path that branches off from the supply flow path is defined as one end and the opposite side is defined as the other end, the pump causes the liquid to flow from the one end to the other end, and the other end may be connected to the liquid storage section.

[0080] According to this configuration, the branch flow path connects the supply flow path downstream of the liquid storage portion to the liquid storage portion. The pump drives the liquid in the branch flow path. The liquid is sent to the supply flow path, the branch flow path, and the liquid storage portion in that order, and circulates by passing through the first filter. Therefore, even when using a liquid that tends to settle, settling can be reduced. [Explanation of symbols]

[0081] 11...liquid ejection device, 12...ejection section, 13...supply mechanism, 14...adjustment mechanism, 15...control section, 16...mounting section, 17...liquid supply source, 19...nozzle, 21...supply flow path, 22...liquid storage section, 23...first filter, 24...second flexible membrane, 25...drive section, 26...second filter, 27...branching section, 28...branching flow path, 29...pump, 30...liquid level detection sensor, 32...supply needle, 34...supply chamber, 36...air-liquid interface, 38...first flexible membrane, 39...valve section, 40...suction section, 42...cap, 43...discharge flow path, 44...pressure reduction section, 45...waste liquid storage section, 46...lip section, D...liquid delivery direction, Z...vertical direction.

Claims

1. an ejection unit capable of ejecting a liquid onto a medium; a supply flow path capable of supplying the liquid to the ejection portion; a gas-liquid exchanger connected to the supply flow path and capable of storing the liquid, the gas-liquid exchanger being in contact with the liquid and air; a liquid reservoir in which an interface is formed; a first filter provided below the gas-liquid interface and separating the supply flow path from the liquid storage section; Luther and an adjustment mechanism capable of raising the height of the gas-liquid interface in the liquid storage portion; a control unit that controls the adjustment mechanism; Equipped with When the direction of the liquid flowing through the supply flow path is defined as the liquid sending direction, The adjustment mechanism includes: a valve portion provided in the supply flow path upstream of the liquid storage portion in the liquid sending direction; A suction action that sucks the liquid in the liquid storage portion and flows the liquid downstream in the liquid sending direction. a suction unit that performs the operation; and The control unit controls the suction operation to close the gas-liquid interface. a lowering operation is performed to lower the gas-liquid interface from the first filter by the lowering operation; The liquid ejection device is characterized in that the valve portion is opened when the valve portion is lowered to the bottom.

2. the adjustment mechanism has a first flexible membrane provided above the gas-liquid interface; The first flexible film has a first retracted position and a second retracted position. and a first advanced position, and the first retracted position is moved from the first retracted position to the The volume of the liquid storage portion is reduced by advancing to the first advanced position.

2. The liquid ejection device according to claim 1.

3. a second flexible membrane provided below the first filter; The second flexible film is moved to a second retracted position and then moved toward the first filter side from the second retracted position. a drive unit capable of moving the cartridge to a second advanced position; Furthermore, The driving unit is configured to drive the front filter when the gas-liquid interface is located above the first filter. The second flexible membrane is advanced from the second retracted position to the second advanced position, thereby 3. The liquid ejection device according to claim 2, wherein the volume of the passage is reduced.

4. An ejection unit capable of ejecting a liquid onto a medium; a supply flow path capable of supplying the liquid to the ejection portion; a gas-liquid exchanger connected to the supply flow path and capable of storing the liquid, the gas-liquid exchanger being in contact with the liquid and air; a liquid reservoir in which an interface is formed; a first filter provided below the gas-liquid interface and separating the supply flow path from the liquid storage section; Luther and an adjustment mechanism capable of raising the height of the gas-liquid interface in the liquid storage portion; a control unit that controls the adjustment mechanism; Equipped with Detecting that the position of the gas-liquid interface is at a predetermined position above the first filter. It is equipped with a liquid level detection sensor, The control unit determines whether the gas-liquid interface is at the predetermined level based on the detection by the liquid level detection sensor. When the liquid is lowered to the lower position, the adjusting mechanism is controlled to raise the gas-liquid interface. A liquid injection device.

5. An ejection unit capable of ejecting a liquid onto a medium; a supply flow path capable of supplying the liquid to the ejection portion; a gas-liquid exchanger connected to the supply flow path and capable of storing the liquid, the gas-liquid exchanger being in contact with the liquid and air; a liquid reservoir in which an interface is formed; a first filter provided below the gas-liquid interface and separating the supply flow path from the liquid storage section; Luther and an adjustment mechanism capable of raising the height of the gas-liquid interface in the liquid storage portion; Equipped with When the direction of the liquid flowing through the supply flow path is defined as the liquid sending direction, a second liquid supply passage provided in the supply flow path downstream of the liquid storage portion in the liquid sending direction; It also has a filter, The second filter has finer mesh than the first filter. shooting device.

6. An ejection unit capable of ejecting liquid onto a medium; a supply flow path capable of supplying the liquid to the ejection portion; a gas-liquid exchanger connected to the supply flow path and capable of storing the liquid, the gas-liquid exchanger being in contact with the liquid and air; a liquid reservoir in which an interface is formed; a first filter provided below the gas-liquid interface and separating the supply flow path from the liquid storage section; Luther and an adjustment mechanism capable of raising the height of the gas-liquid interface in the liquid storage portion; Equipped with When the direction of the liquid flowing through the supply flow path is defined as the liquid sending direction, a branch that separates from the supply flow path downstream of the liquid storage portion in the liquid sending direction; a flow path; a pump for causing the liquid in the branch flow path to flow; Furthermore, When the branch flow path is defined as one end side branching from the supply flow path and the opposite side is defined as the other end side, To, The pump causes the liquid to flow from the one end side to the other end side, The other end of the nozzle is connected to the liquid reservoir.

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