LIQUID EJECTOR AND AGITATOR METHOD FOR LIQUID EJECTOR

Abstract

To provide a liquid discharge device and a stirring method of a liquid discharge device which can sufficiently blend humidified fluid with water supplied from a water supply part.SOLUTION: A liquid discharge device 11 comprises: a liquid discharge head; a cap 22 which has a closed space forming part 31 forming a closed space, an inflow port 37 into which humidified fluid L1 for humidifying the closed space flows, and an outflow port 38 from which the humidified fluid L1 flows; a humidified fluid storage part 39 that stores the humidified fluid L1; a supply passage 40 through which the humidified fluid storage part 39 is communicated with the inflow port 37; a recovery passage 41 through which the humidified fluid storage part 39 is communicated with the outflow port 38; a second pump 53; a moisture supply part 56; and a control part 77. One end 41a of the recovery passage 41 opens to a position lower than liquid level of the humidified fluid L1 in the humidified fluid storage part 39. The control part 77 makes the moisture supply part 56 supply moisture L2 into a circulation passage 42 and drives the second pump 53 so as to make the humidification fluid L1 flow in the circulation passage 42, as first stirring and circulating.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection device, such as an inkjet printer, and a stirring method for the liquid ejection device. [Background technology]

[0002] A liquid ejection apparatus, which is an example of a liquid ejection apparatus described in Patent Document 1, includes a capping device. The capping device humidifies the nozzles by bringing a cap into contact with the liquid ejection head to form a space surrounding the nozzles, and then supplying moisturizing liquid from a moisturizing liquid reservoir into the space through a connecting flow path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-38159 Summary of the Invention [Problem to be solved by the invention]

[0004] In the liquid ejection device described above, if the water content of the moisturizer in the moisturizer reservoir evaporates, it is necessary to supply water to the moisturizer reservoir in order to maintain the concentration of the moisturizer. However, when water is supplied to the moisturizer, there is a problem in that the moisturizer and the supplied water do not easily mix. [Means for solving the problem]

[0005] A liquid ejection device that solves the above problem comprises a liquid ejection head capable of ejecting liquid from a nozzle, a closed space forming portion capable of forming a closed space in which the nozzle opens upon contact with the liquid ejection head, a cap having an inlet through which humidifying fluid flows to humidify the closed space and an outlet through which the humidifying fluid flows out, a humidifying fluid storage portion that stores the humidifying fluid, a supply flow path that connects the humidifying fluid storage portion to the inlet, a recovery flow path that connects the humidifying fluid storage portion to the outlet, a pump that can flow the humidifying fluid within a circulation path that includes the humidifying fluid storage portion, the supply flow path, and the recovery flow path, a water supply portion that can supply water within the circulation path, and a control portion, wherein one end of the recovery flow path opens at a position lower than the liquid level of the humidifying fluid within the humidifying fluid storage portion, and the control portion supplies water into the circulation path using the water supply portion and drives the pump to flow the humidifying fluid within the circulation path as a first agitation circulation.

[0006] A stirring method for a liquid ejection device that solves the above problem includes a liquid ejection head capable of ejecting liquid from a nozzle, a closed space forming portion capable of forming a closed space in which the nozzle opens upon contact with the liquid ejection head, a cap having an inlet through which humidifying fluid flows to humidify the closed space and an outlet through which the humidifying fluid flows out, a humidifying fluid storage portion that stores the humidifying fluid, a supply flow path that connects the humidifying fluid storage portion with the inlet, a recovery flow path that connects the humidifying fluid storage portion with the outlet, a pump that can cause the humidifying fluid to flow within a circulation path that includes the humidifying fluid storage portion, the supply flow path, and the recovery flow path, and a water supply portion that can supply water into the circulation path, wherein one end of the recovery flow path opens at a position lower than the liquid level of the humidifying fluid within the humidifying fluid storage portion, and a first stirring circulation is performed in which the water supply portion supplies water into the circulation path and the pump is driven to cause the humidifying fluid to flow within the circulation path. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view illustrating a liquid ejection device according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the arrangement of components around the liquid ejection head. [Figure 3] FIG. 2 is a schematic diagram illustrating a configuration of a maintenance device. [Figure 4] FIG. 2 is a block diagram showing the electrical configuration of the liquid ejection device. [Figure 5] 10 is a flowchart showing an installation stirring process routine. [Figure 6] 10 is a flowchart showing a post-installation stirring processing routine. [Figure 7] 10 is a flowchart showing a post-printing stirring process routine. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of a liquid ejection apparatus and an agitation method therefor will be described with reference to the drawings. The liquid ejection device is, for example, an inkjet printer that prints by ejecting ink, which is an example of a liquid, onto a medium such as paper.

[0009] In the drawings, the liquid ejection device 11 is placed on a flat surface. The width and depth directions are substantially horizontal. The vertical direction is indicated by the Z axis, and the directions along the plane intersecting the Z axis are indicated by the X and Y axes. It is preferable that the X, Y, and Z axes are perpendicular to one another. In the following description, the X axis direction is also referred to as the width direction X, the Y axis direction as the depth direction Y, and the Z axis direction as the vertical direction Z.

[0010] <Liquid discharge device 11> 1 and 2, the liquid ejection device 11 includes a rectangular parallelepiped main body 12, an image reading unit 13 attached on the main body 12, and an automatic feeder 14 attached on the image reading unit 13. That is, the liquid ejection device 11 has a structure in which the main body 12, the image reading unit 13, and the automatic feeder 14 are stacked in this order from the bottom in the vertical direction Z.

[0011] The image reading unit 13 is configured to be able to read images such as characters and photographs recorded on a document. The automatic feeding unit 14 is configured to be able to feed a set document toward the image reading unit 13. The image reading unit 13 has an operation unit 15 for operating the liquid ejection device 11. The operation unit 15 has, for example, a touch panel type liquid crystal display and operation buttons.

[0012] The main body 12 has a plurality of medium storage sections 16 that can store media M, such as paper. The main body 12 has one or more medium storage sections 16. The number of medium storage sections 16 that the main body 12 has may be changed as desired. The medium storage sections 16 are configured to be removable from the main body 12.

[0013] The main body 12 has a printing unit 17 that prints on the medium M within the main body 12. The printing unit 17 is equipped with a head unit 19 that has a liquid ejection head 18 that can eject liquid. The main body 12 has a mounting unit 20 on top of it on which the medium M after printing is placed. The mounting unit 20 has a mounting surface 20a on which the medium M is placed.

[0014] The media M stored in the media storage unit 16 are transported along a transport path 21 from the media storage unit 16 through the printing unit 17 to the loading unit 20. A feed roller (not shown) rotates in contact with the topmost medium M among the plurality of media M stored in the media storage unit 16, thereby sending the topmost medium M from the media storage unit 16 to the printing unit 17 located above the media storage unit 16.

[0015] The liquid ejection head 18 ejects ink, an example of a liquid, toward the medium M as the medium M passes through the printing unit 17. Printing is performed when the ink ejected from the liquid ejection head 18 adheres to the medium M. After printing, the medium M is ejected onto the loading unit 20 by a pair of ejection rollers (not shown).

[0016] <Print section 17> 2, a cap 22 is disposed in a position around the liquid ejection head 18 provided in the printing section 17, on the opposite side of the head unit 19 with respect to the transport path 21. The head unit 19 includes the liquid ejection head 18 and a support section 23 that holds the liquid ejection head 18.

[0017] The liquid ejection head 18 is configured to eject liquid onto the medium M from a plurality of nozzles 24 that make up a plurality of nozzle groups, while extending in the width direction X. In the following description, the direction in which the liquid is ejected when the liquid ejection head 18 ejects liquid onto the medium M is referred to as the ejection direction Y1. The direction in which the medium M is transported when the liquid ejection head 18 ejects liquid onto the medium M is referred to as the transport direction Z1.

[0018] The surface of the liquid ejection head 18 where the nozzles 24 open is referred to as the nozzle surface 25. The nozzle surface 25 does not have to be horizontal, for example. That is, the liquid ejection head 18 is disposed, for example, in a position where the nozzle surface 25 forms a predetermined angle θ1 with respect to the horizontal plane. The liquid ejection head 18 ejects liquid from the nozzles 24 onto the medium M, for example, in a position where the nozzle surface 25 forms a predetermined angle θ1 with respect to the horizontal plane. The liquid ejection head 18 may also be disposed in a position where the nozzle surface 25 is horizontal.

[0019] The liquid ejection head 18 is, for example, a line head having a number of nozzles 24 that can simultaneously eject liquid across the entire width of the medium M in the width direction X that intersects with the transport direction Z1 and the ejection direction Y1. The liquid ejection device 11 performs line printing by ejecting liquid from the multiple nozzles 24 that are positioned opposite the entire width of the medium M toward the medium M that is transported at a constant speed.

[0020] In the liquid ejection device 11, maintenance operations such as capping, cleaning, and flushing are performed to prevent or resolve liquid ejection problems caused by clogging of the nozzles 24 of the liquid ejection head 18 or adhesion of foreign matter to the nozzles 24. The liquid ejection device 11 is equipped with a maintenance device 26 (see FIG. 3) for performing the above-mentioned maintenance operations.

[0021] <Maintenance operation> 2, capping refers to the operation of bringing a cap 22 into contact with the nozzle surface 25 of the liquid ejection head 18 so as to surround the nozzle 24 when the liquid ejection head 18 is not ejecting liquid. Capping suppresses the viscosity of the liquid inside the nozzle 24, thereby preventing poor ejection of the liquid from the nozzle 24.

[0022] Cleaning refers to an operation of applying pressure to the upstream side of the liquid ejection head 18 to forcibly expel liquid from the nozzles 24, or applying suction force to the nozzles 24 of the liquid ejection head 18 to forcibly expel liquid from the nozzles 24.

[0023] Flushing refers to the operation of ejecting droplets from the nozzles 24 independently of printing. Flushing expels thickened ink, air bubbles, foreign matter, and other substances that can cause ejection problems from the nozzles 24, thereby preventing clogging of the nozzles 24. Of the liquid ejected from the liquid ejection head 18, the liquid that is not used for printing is called waste liquid.

[0024] The liquid discharged by flushing is not used for printing and is therefore waste liquid. The waste liquid L3 discharged by flushing is received, for example, in the cap 22. That is, flushing is performed by the liquid ejection head 18 discharging droplets from the nozzles 24 toward the inside of the cap 22, for example.

[0025] The position of the head unit 19 when the liquid ejection head 18 ejects liquid onto the medium M to print on the medium M is called the printing position. The position of the cap 22 when the liquid ejection head 18 ejects liquid onto the medium M to print on the medium M is called the retracted position. The position of the head unit 19 when the liquid ejection device 11 performs a maintenance operation is called the maintenance position. The position of the cap 22 when the liquid ejection device 11 performs a maintenance operation is also called the maintenance position.

[0026] The head unit 19 is moved by a head unit moving mechanism 27 (see FIG. 4) between a printing position indicated by a solid line in FIG. 2 and a maintenance position indicated by a two-dot chain line in FIG. 2. The direction in which the head unit 19 moves from the printing position to the maintenance position is called a first direction D1. The direction in which the head unit 19 moves from the maintenance position to the printing position is called a second direction D2.

[0027] The cap 22 is moved by a cap moving mechanism 28 (see FIG. 4) between a retracted position indicated by a solid line in FIG. 2 and a maintenance position indicated by a two-dot chain line in FIG. 2. The direction in which the cap 22 moves from the retracted position to the maintenance position is referred to as a third direction D3. The direction in which the cap 22 moves from the maintenance position to the retracted position is referred to as a fourth direction D4.

[0028] As shown in Fig. 2, the cap 22 is moved in the third direction D3 from the retracted position shown by the solid line in Fig. 2 to the maintenance position shown by the two-dot chain line in Fig. 2. After that, the head unit 19 is moved in the first direction D1 from the printing position shown by the solid line in Fig. 2 to the maintenance position shown by the two-dot chain line in Fig. 2. This brings the head unit 19 into a state where it is capped by the cap 22.

[0029] In this state, flushing is performed by ejecting droplets from the nozzles 24 of the liquid ejection head 18 into the cap 22. That is, in the liquid ejection device 11 of this embodiment, both capping and flushing are performed at the maintenance position. Flushing may also be performed when the liquid ejection head 18 is separated from the cap 22.

[0030] When maintenance operations such as flushing are completed, the head unit 19 is moved in the second direction D2 from the maintenance position shown by the two-dot chain line in Fig. 2 to the printing position shown by the solid line in Fig. 2. Thereafter, the cap 22 is moved in the fourth direction D4 from the maintenance position shown by the two-dot chain line in Fig. 2 to the retracted position shown by the solid line in Fig. 2.

[0031] <Maintenance Device 26> As shown in FIGS. 2 and 3, the maintenance device 26 includes the cap 22, a cap moving mechanism 28, a humidified fluid circulating mechanism 29, and a waste liquid collecting mechanism 30.

[0032] <Cap 22> 2 and 3, the cap 22 has a closed space forming portion 31 in the shape of a bottomed box with one open end. The open end of the closed space forming portion 31 comes into contact with the nozzle surface 25 of the liquid ejection head 18, thereby forming a closed space in which the nozzles 24 are open. A humidification chamber 32 is formed in the center of the bottom of the closed space forming portion 31. The space within the closed space forming portion 31 includes the humidification chamber 32 and a waste liquid storage area 33.

[0033] The waste liquid storage area 33 is an area other than the humidification chamber 32 in the space within the closed space forming portion 31, where the waste liquid L3 is stored. An absorber (not shown) capable of absorbing and retaining the waste liquid L3 may be placed in the waste liquid storage area 33. The humidification chamber 32 is separated from the waste liquid storage area 33 by a partition wall 34, which does not allow liquid to pass through. A portion of the partition wall 34 is formed of a first moisture-permeable membrane 35 that is gas-permeable. The first moisture-permeable membrane 35 allows gas to pass through but prevents liquid from passing through.

[0034] The closed space forming section 31 is formed with an atmosphere communication hole 36, an inlet 37, and an outlet 38 that communicate between the inside and outside of the closed space forming section 31. The atmosphere communication hole 36 is located at the top of the closed space forming section 31 and communicates with the waste liquid storage area 33. The inlet 37 and outlet 38 each communicate with the humidifying chamber 32. A humidifying fluid L1 flows into the humidifying chamber 32 from the inlet 37. The humidifying fluid L1 humidifies the closed space formed by the closed space forming section 31. The humidifying fluid L1 contains, for example, glycerin, a type of humidifier, and water. The concentration of the humidifier in the humidifying fluid L1 is set to, for example, 22.5±5%. The humidifying fluid L1 is conductive. The humidifying fluid L1 that flows into the humidifying chamber 32 from the inlet 37 flows out from the outlet 38.

[0035] <Humidifying fluid circulation mechanism 29> 3, the humidified fluid circulation mechanism 29 includes a humidified fluid storage section 39, a supply flow path 40, and a recovery flow path 41. The supply flow path 40 connects the humidified fluid storage section 39 to the inlet 37. That is, the humidified fluid storage section 39 connects to the humidifying chamber 32 via the supply flow path 40 and the inlet 37.

[0036] The recovery flow path 41 connects the humidifying fluid storage unit 39 with the outlet 38. That is, the humidifying fluid storage unit 39 connects with the humidifying chamber 32 via the recovery flow path 41 and the outlet 38. The humidifying fluid circulation mechanism 29 includes a circulation path 42 that includes the humidifying fluid storage unit 39, the supply flow path 40, and the recovery flow path 41.

[0037] The humidifying fluid storage unit 39 has an upper wall 43, a peripheral wall 44, and a bottom wall 45. The humidifying fluid storage unit 39 stores humidifying fluid L1 therein. The recovery flow path 41 passes through the upper wall 43 and extends to the lower end of the humidifying fluid storage unit 39. One end 41a of the recovery flow path 41 opens at a position lower than the liquid level of the humidifying fluid L1 in the humidifying fluid storage unit 39. The recovery flow path 41 may also be configured to pass through the peripheral wall 44 so that one end 41a opens at a position lower than the liquid level of the humidifying fluid L1 in the humidifying fluid storage unit 39.

[0038] The liquid level of the humidifying fluid L1 in the humidifying fluid storage portion 39 includes a liquid level that has dropped due to evaporation of water in the humidifying fluid L1. One end 40a of the supply flow path 40 is connected to the lower end of the peripheral wall 44. One end 40a of the supply flow path 40 communicates with the inside of the humidifying fluid storage portion 39. The humidifying fluid storage portion 39 is equipped with a detection portion 46 that detects the liquid level of the humidifying fluid L1 in the humidifying fluid storage portion 39. The detection portion 46 has a first electrode 47 and a second electrode 48.

[0039] The first electrode 47 and the second electrode 48 extend in a straight line side by side downward from the upper surface (the lower surface of the upper wall 43) inside the humidifying fluid storage section 39. The length of the first electrode 47 is shorter than the length of the second electrode 48. The height of the lower end of the first electrode 47 from the bottom surface inside the humidifying fluid storage section 39 is set to a first height H. The detection section 46 detects the liquid level of the humidifying fluid L1 inside the humidifying fluid storage section 39 based on the presence or absence of electrical continuity between the first electrode 47 and the second electrode 48.

[0040] When the liquid level of the humidifying fluid L1 contained in the humidifying fluid container 39 is equal to or higher than the first height H, the first electrode 47 and the second electrode 48 are electrically connected. When the liquid level of the humidifying fluid L1 contained in the humidifying fluid container 39 is lower than the first height H, the first electrode 47 and the second electrode 48 are not electrically connected.

[0041] Therefore, by checking whether the first electrode 47 and the second electrode 48 are conductive, it is possible to determine whether the liquid level of the humidifying fluid L1 contained in the humidifying fluid storage portion 39 is equal to or greater than the first height H or less than the first height H. The method for determining whether the liquid level of the humidifying fluid L1 contained in the humidifying fluid storage portion 39 is equal to or greater than the first height H or less than the first height H is not limited to the electrode method described above, and an optical method or a capacitance method may also be used.

[0042] When the liquid level of the humidifying fluid L1 contained in the humidifying fluid storage section 39 is equal to or higher than the first height H, the concentration of the humidifying agent in the humidifying fluid L1 can be determined from the value of the current flowing between the first electrode 47 and the second electrode 48 when a constant voltage is applied between the first electrode 47 and the second electrode 48.

[0043] The position of one end 41a of the recovery passageway 41 within the humidifying fluid storage section 39 may be a position at or below a height corresponding to the concentration of the humidifier in the humidifying fluid L1 (in this example, 22.5±5%) when the liquid level of the humidifying fluid L1 is at the first height H. The position of one end 41a of the recovery passageway 41 within the humidifying fluid storage section 39 may be a position at or below the height of the lower end of the second electrode 48 of the detection section 46.

[0044] The position of one end 41a of the recovery flow path 41 within the humidifying fluid storage portion 39 may be at a position equal to or lower than the height of the connection between one end 40a of the supply flow path 40 and the peripheral wall 44 of the humidifying fluid storage portion 39. The position of one end 41a of the recovery flow path 41 within the humidifying fluid storage portion 39 may be at a position equal to or lower than half the height of the highest liquid level of the humidifying fluid L1 within the humidifying fluid storage portion 39.

[0045] The humidifying fluid storage portion 39 has a first atmosphere communication passage 49 and a second moisture-permeable membrane 50. The first atmosphere communication passage 49 connects the interior of the humidifying fluid storage portion 39 to the atmosphere. One end of the first atmosphere communication passage 49 is connected to the upper wall 43 of the humidifying fluid storage portion 39, and the other end is open to the atmosphere. One end of the first atmosphere communication passage 49 connects to the interior of the humidifying fluid storage portion 39. The first atmosphere communication passage 49 is provided with a first on-off valve 51 and a first pump 52 as an example of a pressure reducing portion. The first pump 52 is, for example, a pressure reducing pump.

[0046] The first on-off valve 51 is disposed at a position closer to the humidifying fluid storage unit 39 than the first pump 52. The first pump 52 is driven with the first on-off valve 51 open to suction the inside of the humidifying fluid storage unit 39. In other words, the first pump 52 reduces the pressure in the space inside the humidifying fluid storage unit 39 by driving the first on-off valve 51 open.

[0047] A labyrinthine thin tube structure may be formed in the first atmosphere communication passage 49 instead of or in addition to the first on-off valve 51. A labyrinthine thin tube structure is a pipe structure having a narrow, winding, and complex path that allows air to pass in and out but significantly restricts the passage of liquid. The labyrinthine thin tube structure suppresses evaporation of liquid (such as the water content of the humidifying fluid L1) in the humidifying fluid storage section 39.

[0048] The second moisture permeable membrane 50 is provided at the connection between the humidifying fluid storage section 39 and the first atmosphere communicating passage 49. The second moisture permeable membrane 50 is provided inside the humidifying fluid storage section 39 in a state covering one end of the first atmosphere communicating passage 49. The second moisture permeable membrane 50 allows gas to pass through but prevents liquid from passing through.

[0049] 3, the humidified fluid circulation mechanism 29 includes a second pump 53 as an example of a pump capable of causing the humidified fluid L1 to flow within the circulation path 42, a first check valve 54, and a pressure adjustment valve 55. The second pump 53 causes the humidified fluid L1 to flow within the circulation path 42. When the second pump 53 is driven, the humidified fluid L1 flowing through the supply flow path 40 is sent to the humidifying chamber 32 within the closed space forming portion 31 of the cap 22.

[0050] The first check valve 54 allows the humidifying fluid L1 to flow from the humidifying fluid storage portion 39 side to the cap 22 side, and prevents the humidifying fluid L1 from flowing back from the cap 22 side to the humidifying fluid storage portion 39 side due to a head difference. An on-off valve may be used instead of the first check valve 54. Then, when this on-off valve is opened, the second pump 53 may be driven to cause the humidifying fluid L1 to flow from the humidifying fluid storage portion 39 side to the cap 22 side.

[0051] The pressure adjustment valve 55 allows the flow of humidifying fluid L1 from the cap 22 side to the humidifying fluid storage section 39 side when a predetermined negative pressure is reached on the humidifying fluid storage section 39 side, and always prevents the backflow of humidifying fluid L1 from the humidifying fluid storage section 39 side to the cap 22 side. The pressure adjustment valve 55 adjusts the pressure difference of the head differential so that the humidifying fluid L1 does not flow from the cap 22 side to the humidifying fluid storage section 39 side due to head pressure.

[0052] 3, the humidified fluid circulation mechanism 29 includes a moisture supply unit 56 that serves as a water supply unit capable of supplying moisture L2 as water into the circulation path 42. The moisture supply unit 56 includes a moisture storage unit 57, a moisture supply flow path 58, a second on-off valve 59, and a second check valve 60. The moisture storage unit 57 stores moisture L2 that can be supplied into the circulation path 42. The moisture supply flow path 58 communicates with the circulation path 42. The second on-off valve 59 opens and closes the moisture supply flow path 58.

[0053] The moisture storage section 57 has an outflow section 61. The moisture storage section 57 communicates with a moisture supply flow path 58 at the outflow section 61. The moisture supply flow path 58 communicates with the circulation path 42 at a first junction 62 of the circulation path 42. In other words, the moisture storage section 57 and the circulation path 42 communicate with each other. It is desirable that the moisture storage section 57 be configured to be replaceable. The moisture L2 supplied from the moisture storage section 57 into the circulation path 42 is moisture to replenish the moisture that has evaporated from the humidifying fluid L1. The moisture L2 is composed of, for example, pure water and a small amount of an antiseptic.

[0054] When the second on-off valve 59 is opened, the moisture storage section 57 and the circulation path 42 are connected via the moisture supply flow path 58. The second check valve 60 allows the flow of moisture L2 from the moisture storage section 57 side to the circulation path 42 side, and prevents the backflow of humidifying fluid L1 from the circulation path 42 side to the moisture storage section 57 side due to a head difference. The second check valve 60 may be omitted. In the case where the second check valve 60 is omitted, the second pump 53 may be driven at the same time as the second on-off valve 59 is opened, thereby causing the moisture L2 to flow from the moisture storage section 57 side to the cap 22 side.

[0055] As shown in FIG. 3 , the humidified fluid circulation mechanism 29 includes a pressurized air supply unit 63. The pressurized air supply unit 63 is configured to be able to supply pressurized air into the circulation path 42. The pressurized air supply unit 63 has a pressurized air supply path 64 that communicates with the circulation path 42, a third on-off valve 65, and a third pump 66. When the third on-off valve 65 is opened, the third pump 66 communicates with the circulation path 42 via the pressurized air supply path 64. The third pump 66 is, for example, a pressure pump. The third pump 66 applies pressure to the atmosphere to generate pressurized air, and supplies the pressurized air to the pressurized air supply path 64.

[0056] In the circulation path 42, instead of providing the pressurized air supply unit 63 downstream of the second pump 53, an atmosphere supply unit may be provided upstream of the second pump 53 and downstream of the first junction 62. This atmosphere supply unit may have an atmosphere communication passage communicating with the atmosphere and an on-off valve. Then, the atmosphere may be sent to the circulation path 42 by driving the second pump 53 in a state where the circulation path 42 and the atmosphere are communicated with each other through the atmosphere communication passage by opening the on-off valve.

[0057] <Waste liquid recovery mechanism 30> As shown in FIG. 3, the waste liquid recovery mechanism 30 includes a waste liquid recovery path 67 , a fourth pump 68 , a buffer chamber 69 , a fifth pump 70 , a second atmosphere communication path 71 , and a waste liquid storage section 72 .

[0058] The waste liquid recovery path 67 communicates with the waste liquid storage area 33 in the closed space forming part 31 at a discharge hole 73 formed in the lower end of the closed space forming part 31 of the cap 22. The waste liquid recovery path 67 communicates between the waste liquid storage area 33 and the waste liquid storage part 72 through a buffer chamber 69. The buffer chamber 69 is provided, for example, at a midpoint of the waste liquid recovery path 67.

[0059] When flushing, cleaning, or the like is performed, ink, which is an example of a liquid, is discharged as waste liquid L3 from the nozzles 24 of the liquid ejection head 18 into the closed space forming portion 31 of the cap 22. This waste liquid L3 is collected from the closed space forming portion 31 and flows into the waste liquid collection path 67. The waste liquid L3 collected by flushing or cleaning is sent to the waste liquid storage portion 72 by the fourth pump 68. The waste liquid L3 is then stored in the waste liquid storage portion 72.

[0060] The fifth pump 70 is, for example, a pressure reducing pump. The fifth pump 70 lowers the air pressure inside the buffer chamber 69 by discharging the air inside the buffer chamber 69 to the outside through the second atmosphere communicating passage 71. This makes it easier for the waste liquid L3 discharged from the nozzles 24 of the liquid ejection head 18 into the closed space forming portion 31 of the cap 22 during flushing or cleaning to flow into the buffer chamber 69 through the waste liquid recovery passage 67. The buffer chamber 69, the fifth pump 70, and the second atmosphere communicating passage 71 may be omitted.

[0061] 3, the cap 22 has an atmosphere vent mechanism 74. The atmosphere vent mechanism 74 has a third atmosphere communication passage 75 and a fourth on-off valve 76. The third atmosphere communication passage 75 connects the atmosphere communication hole 36 in the cap 22 with the atmosphere. The fourth on-off valve 76 opens and closes the third atmosphere communication passage 75.

[0062] <Electrical configuration of the liquid ejection device 11> 4, the liquid ejection device 11 includes a control unit 77 that controls the head unit 19, head unit moving mechanism 27, cap moving mechanism 28, maintenance device 26, etc. The maintenance device 26 includes a detector group 78 that outputs a detection signal to the control unit 77. The detector group 78 includes a detector 46 that detects the liquid level of the humidifying fluid L1 in the humidifying fluid storage unit 39. The detector 46 outputs the detection signal to the control unit 77.

[0063] The control unit 77 includes an interface unit 79, a CPU 80, a memory 81, a timer 82 as an example of a measurement unit, a control circuit 83, and a drive circuit 84. The interface unit 79 transmits and receives various data between a computer 85 as an example of an external device and the liquid ejection device 11. The drive circuit 84 generates a drive signal that drives the actuator of the liquid ejection head 18.

[0064] The CPU 80 is a central processing unit. The memory 81 is a storage device that secures an area for storing various programs executed by the CPU 80, a working area, etc., and has memory elements such as RAM and EEPROM. The memory 81 stores various programs and various information, including the installation stirring process routine, post-installation stirring process routine, and post-print stirring process routine shown in the flowcharts of FIGS. 5 to 7. The CPU 80 controls the head unit 19, head unit moving mechanism 27, cap moving mechanism 28, maintenance device 26, etc. via a control circuit 83 in accordance with the programs stored in the memory 81.

[0065] The timer 82 measures various times, including unused time, which is time when the liquid ejection device 11 is not in use. This unused time is, for example, the time from when the power of the liquid ejection device 11 is turned off to when the power of the liquid ejection device 11 is turned on.

[0066] <Agitation Operation of Humidification Fluid L1 in Humidification Fluid Storage Section 39> 3, as the first agitation circulation, the control unit 77 supplies moisture L2 into the circulation path 42 by the moisture supply unit 56 and drives the second pump 53 to circulate the humidifying fluid L1 in the circulation path 42. The supply of moisture L2 into the circulation path 42 by the moisture supply unit 56 is performed by the control unit 77 opening the second on-off valve 59.

[0067] In the first agitation circulation, the supply of water L2 into the circulation path 42 and the drive of the second pump 53 may be performed at any timing. That is, in the first agitation circulation, the two operations of supplying water L2 into the circulation path 42 and the drive of the second pump 53 may be performed simultaneously, one may be performed before the other, or one and the other may be performed alternately one or more times.

[0068] In the first agitation circulation, for example, when the second pump 53 is driven with the second on-off valve 59 open, the humidifying fluid L1 in the humidifying fluid storage portion 39 is sent to the humidifying chamber 32 through the supply flow path 40. At this time, the moisture L2 in the moisture storage portion 57 flows into the circulation path 42 via the moisture supply flow path 58 and the first junction 62, and is then sent to the humidifying chamber 32 through the supply flow path 40 together with the humidifying fluid L1 from the humidifying fluid storage portion 39.

[0069] The humidifying fluid L1 sent to the humidifying chamber 32 through the supply flow path 40 and the moisture L2 from the moisture storage section 57 are sent into the humidifying fluid storage section 39 through the recovery flow path 41. At this time, one end 41a of the recovery flow path 41 opens at a position lower than the liquid level of the humidifying fluid L1 in the humidifying fluid storage section 39. Therefore, the humidifying fluid L1 sent from the humidifying chamber 32 into the humidifying fluid storage section 39 through the recovery flow path 41 and the moisture L2 from the moisture storage section 57 are sent from one end 41a of the recovery flow path 41 into the humidifying fluid L1 in the humidifying fluid storage section 39.

[0070] This causes the humidifying fluid L1 in the humidifying fluid storage portion 39 to flow in all directions, including from bottom to top, and these flows efficiently agitate the humidifying fluid L1 in the humidifying fluid storage portion 39. Therefore, the humidifying fluid L1 delivered from one end 41a of the recovery flow path 41 into the humidifying fluid L1 in the humidifying fluid storage portion 39 and the moisture L2 from the moisture storage portion 57 can be sufficiently mixed with the humidifying fluid L1 in the humidifying fluid storage portion 39.

[0071] The first agitation circulation may be performed in a state where the closed space forming portion 31 of the cap 22 is in contact with the nozzle surface 25 of the liquid ejection head 18 to form a closed space in which the nozzles 24 are open, and the fourth on-off valve 76 is closed, i.e., the inside of the closed space forming portion 31 is sealed. The first agitation circulation may be performed in a state where the inside of the closed space forming portion 31 of the cap 22 is in communication with the atmosphere.

[0072] The closed space forming part 31 is brought into a state of communication with the atmosphere by moving it away from the nozzle surface 25 of the liquid ejection head 18. Even when the closed space forming part 31 comes into contact with the nozzle surface 25 of the liquid ejection head 18 to form a closed space in which the nozzles 24 are open, the closed space forming part 31 is brought into a state of communication with the atmosphere by opening the fourth on-off valve 76.

[0073] The first agitation circulation includes a short-term first agitation circulation and a long-term first agitation circulation. The short-term first agitation circulation is an operation in which the above-mentioned first agitation circulation is performed for, for example, a first predetermined time (short time). The long-term first agitation circulation is an operation in which the above-mentioned first agitation circulation is performed for a time (long time) longer than the first predetermined time.

[0074] 3, as the second agitation circulation, the control unit 77 supplies moisture L2 into the circulation path 42 using the moisture supply unit 56, and drives the first pump 52 and the second pump 53 to cause the humidifying fluid L1 to flow within the circulation path 42. The second agitation circulation is an operation that adds driving of the first pump 52 to the operation of the first agitation circulation described above. In other words, the second agitation circulation is an operation that performs the first agitation circulation described above while driving the first pump 52 with the first on-off valve 51 open to reduce the pressure inside the humidifying fluid storage unit 39. The second agitation circulation is an agitation operation that is stronger than the first agitation circulation described above.

[0075] In the second agitation circulation, the supply of water L2 into the circulation path 42, the depressurization of the humidifying fluid storage unit 39 by driving the first pump 52, and the driving of the second pump 53 may be performed at any timing. That is, in the second agitation circulation, the three operations of supplying water L2 into the circulation path 42, the depressurization of the humidifying fluid storage unit 39 by driving the first pump 52, and the driving of the second pump 53 may be performed at the following timing. That is, the above three operations may be performed, for example, all simultaneously, or any two of the operations may be performed simultaneously and then the remaining one, or any one of the operations may be performed and then the remaining two operations may be performed simultaneously, or they may be performed one by one sequentially.

[0076] In the second agitation and circulation, for example, the second pump 53 is driven with the second on-off valve 59 open, and the first pump 52 is driven with the first on-off valve 51 open. This reduces the pressure inside the humidifying fluid storage unit 39, and the humidifying fluid L1 inside the humidifying fluid storage unit 39 is sent to the humidifying chamber 32 through the supply flow path 40. At this time, the moisture L2 inside the moisture storage unit 57 flows into the circulation path 42 via the moisture supply flow path 58 and the first junction 62, and is then sent to the humidifying chamber 32 through the supply flow path 40 together with the humidifying fluid L1 from the humidifying fluid storage unit 39.

[0077] Humidifying fluid L1 sent to humidifying chamber 32 via supply flow path 40 and moisture L2 from moisture storage section 57 are sent into humidifying fluid storage section 39 via recovery flow path 41. At this time, the pressure inside humidifying fluid storage section 39 has been reduced by first pump 52, so the pressure inside humidifying fluid storage section 39 is lower than the pressure in humidifying chamber 32. Therefore, due to the difference in pressure between humidifying fluid storage section 39 and the pressure in humidifying chamber 32, humidifying fluid L1 in humidifying chamber 32 and moisture L2 from moisture storage section 57 are sent quickly and smoothly into humidifying fluid storage section 39 via recovery flow path 41.

[0078] Furthermore, at this time, one end 41a of the recovery flow path 41 opens at a position lower than the liquid level of the humidifying fluid L1 in the humidifying fluid storage portion 39. Therefore, the humidifying fluid L1 sent from the humidifying chamber 32 into the humidifying fluid storage portion 39 through the recovery flow path 41 and the moisture L2 from the moisture storage portion 57 are forcefully sent out from one end 41a of the recovery flow path 41 into the humidifying fluid L1 in the humidifying fluid storage portion 39.

[0079] This causes strong flows in all directions, including a bottom-to-top flow, in the humidifying fluid L1 inside the humidifying fluid storage portion 39, and these flows more efficiently agitate the humidifying fluid L1 inside the humidifying fluid storage portion 39. Therefore, the humidifying fluid L1 sent from one end 41a of the recovery flow path 41 into the humidifying fluid L1 inside the humidifying fluid storage portion 39 and the moisture L2 from the moisture storage portion 57 can be mixed with the humidifying fluid L1 inside the humidifying fluid storage portion 39 in a shorter time.

[0080] The second agitation circulation may be performed in a state where the closed space forming portion 31 of the cap 22 is in contact with the nozzle surface 25 of the liquid ejection head 18 to form a closed space in which the nozzles 24 are open, and the fourth on-off valve 76 is closed, i.e., the inside of the closed space forming portion 31 is sealed. The second agitation circulation may be performed in a state where the inside of the closed space forming portion 31 of the cap 22 is in communication with the atmosphere.

[0081] The closed space forming part 31 is brought into a state of communication with the atmosphere by moving it away from the nozzle surface 25 of the liquid ejection head 18. Even when the closed space forming part 31 comes into contact with the nozzle surface 25 of the liquid ejection head 18 to form a closed space in which the nozzles 24 are open, the closed space forming part 31 is brought into a state of communication with the atmosphere by opening the fourth on-off valve 76.

[0082] When the second agitation circulation is performed with the inside of the closed space forming portion 31 of the cap 22 in communication with the atmosphere, not only the humidifying fluid L1 and the moisture L2 from the moisture storage portion 57 are sent from the humidifying chamber 32 through the recovery flow path 41 into the humidifying fluid storage portion 39, but also air via the first moisture permeable membrane 35. That is, not only the humidifying fluid L1 and the moisture L2 from the moisture storage portion 57 but also air are sent from one end 41a of the recovery flow path 41 into the humidifying fluid L1 in the humidifying fluid storage portion 39.

[0083] The air sent from one end 41a of the recovery passage 41 into the humidifying fluid L1 in the humidifying fluid storage unit 39 turns into bubbles and rises toward the liquid surface. This allows the humidifying fluid L1 in the humidifying fluid storage unit 39 to be efficiently and effectively agitated. That is, the humidifying fluid L1 in the humidifying fluid storage unit 39 is efficiently agitated by the air. In other words, as the second agitation circulation, the control unit 77 agitates the humidifying fluid L1 in the humidifying fluid storage unit 39 with the air by opening the first on-off valve 51 and driving the first pump 52 while the inside of the closed space forming unit 31 is connected to the atmosphere. The second agitation circulation is performed, for example, for a second predetermined time period.

[0084] A greater stirring effect can be achieved by sending air to generate bubbles and stirring the humidifying fluid L1 in the humidifying fluid storage section 39 than by sending the humidifying fluid L1 and moisture L2 from the moisture storage section 57. For this reason, it is desirable to perform the second stirring / circulation process while the closed space forming section 31 is in communication with the atmosphere. In this way, the humidifying fluid L1 and moisture L2 from the moisture storage section 57, which are sent from one end 41a of the recovery flow path 41 into the humidifying fluid L1 in the humidifying fluid storage section 39, can be mixed more effectively with the air bubbles.

[0085] <Installation mixing routine> Next, the installation stirring process routine executed by the control unit 77 will be described with reference to the flowchart shown in Fig. 5. The installation stirring process routine is executed after the initial filling of liquid into the liquid ejection head 18 is completed with the power turned on when the liquid ejection device 11 shipped from the factory is installed by a user or serviceman. In the liquid ejection device 11, when the power is turned on during installation, the initial filling of liquid into the liquid ejection head 18 is performed.

[0086] In the liquid ejection device 11, a flag is turned on when the initial filling of the liquid ejection head 18 with liquid is completed. The control unit 77 determines that it is time to install the liquid ejection device 11 by checking the on state of the flag that is turned on when the initial filling of the liquid ejection head 18 with liquid is completed. The flag that is turned on when the initial filling of the liquid ejection head 18 with liquid is completed is turned off when the power is turned off after the installation stirring processing routine is executed.

[0087] 5, when the installation stirring process routine is executed, first, the control unit 77 determines whether the liquid level of the humidifying fluid L1 contained in the humidifying fluid container 39 is equal to or higher than the first height H (step S1). If the determination result in step S1 is positive, the control unit 77 executes a first stirring circulation (step S2) and then ends the installation stirring process routine.

[0088] In step S2, either the short-term first agitation circulation or the long-term first agitation circulation may be performed, but it is preferable to perform the long-term first agitation circulation. If the determination result in step S1 is negative, the control unit 77 performs the second agitation circulation (step S3) and then ends the installation agitation processing routine.

[0089] <Post-installation mixing routine> Next, the post-installation mixing process routine executed by the control unit 77 will be described with reference to the flowchart shown in Fig. 6. The post-installation mixing process routine is executed when the power is turned on after the liquid ejection device 11 has been installed by the user (after the power was turned off during installation). The control unit 77 determines that the liquid ejection device 11 has been installed by confirming that a flag that is turned on when the initial filling of the liquid into the liquid ejection head 18 is complete is in the off state.

[0090] 6, when the post-installation stirring process routine is executed, first, the control unit 77 determines whether the unused time, which is the time during which the liquid discharger 11 has not been used, is equal to or longer than a first time (step S11). The first time is set to, for example, six months. If the determination result of step S11 is positive, the control unit 77 executes a second stirring circulation (step S12) and then ends the post-installation stirring process routine.

[0091] If the determination result of step S11 is negative, the control unit 77 determines whether the unused time is equal to or greater than the second hour and less than the first hour (step S13). The second hour is shorter than the first hour. The second hour is set to, for example, one month. If the determination result of step S13 is positive, the control unit 77 executes the first agitation circulation for a long period of time (step S14) and then ends the post-installation agitation processing routine.

[0092] If the determination result in step S13 is negative, that is, if the unused time is less than the second time, the control unit 77 executes the first agitation circulation for a short time (step S15), and then ends the post-installation agitation processing routine.

[0093] <Post-printing stirring processing routine> Next, the post-printing stirring process routine executed by the control unit 77 will be described with reference to the flowchart shown in Fig. 7. The post-printing stirring process routine is executed after printing by the liquid ejection device 11 (print job) is completed.

[0094] 7, when the post-printing stirring process routine is executed, the control unit 77 first determines whether the liquid level of the humidifying fluid L1 contained in the humidifying fluid container 39 is equal to or greater than the first height H (step S21). If the determination result in step S21 is positive, the control unit 77 ends the printing stirring process routine. If the determination result in step S21 is negative, the control unit 77 performs a first stirring circulation for a short time (step S22) and then ends the post-printing stirring process routine.

[0095] <Operation of the liquid ejection device 11> When the liquid ejector 11 is installed after being shipped from the factory, a long time may have passed before the installation. As a result, moisture L2 may evaporate from the humidifying fluid L1 in the humidifying fluid storage unit 39, increasing the concentration of the humidifier in the humidifying fluid L1. In particular, if the liquid level of the humidifying fluid L1 in the humidifying fluid storage unit 39 is less than the first height H when the liquid ejector 11 is installed, a large amount of moisture L2 will have evaporated from the humidifying fluid L1 in the humidifying fluid storage unit 39.

[0096] This is because when the liquid ejector 11 is manufactured at the factory, the humidifying fluid storage section 39 contains not only the amount of humidifying fluid L1 to be stored in the humidifying fluid storage section 39, but also the amount of humidifying fluid L1 to be supplied to the circulation path 42 and the humidifying chamber 32. If a large amount of moisture L2 evaporates from the humidifying fluid L1 in the humidifying fluid storage section 39 and the concentration of the humidifier in the humidifying fluid L1 increases, it becomes difficult for the supplied moisture L2 to mix with the humidifier, even if the supplied moisture L2 is supplied.

[0097] In this regard, in the liquid ejection device 11 of this embodiment, one end 41a of the recovery flow path 41 in the circulation path 42 is configured to open at a position lower than the liquid level of the humidifying fluid L1 in the humidifying fluid storage unit 39. Furthermore, when the liquid ejection device 11 is installed, if the liquid level of the humidifying fluid L1 in the humidifying fluid storage unit 39 is equal to or higher than the first height H, a first agitation circulation (long-term first agitation circulation or short-term first agitation circulation) is performed. On the other hand, when the liquid ejection device 11 is installed, if the liquid level of the humidifying fluid L1 in the humidifying fluid storage unit 39 is less than the first height H, a second agitation circulation, which is a stronger agitation operation than the first agitation circulation, is performed.

[0098] Furthermore, after the installation of the liquid ejector 11, the longer the time that the liquid ejector 11 has not been used, the greater the amount of evaporation of moisture L2 from the humidifying fluid L1 in the humidifying fluid storage section 39. For this reason, after the installation of the liquid ejector 11, if the time that the liquid ejector 11 has not been used is the first hour or longer, the second agitation circulation is performed.

[0099] After the installation of the liquid ejection device 11, if the time that the liquid ejection device 11 has not been used is equal to or longer than the second hour but less than the first hour, a first long-time agitation circulation, which is a weaker agitation operation than the second agitation circulation, is performed. After the installation of the liquid ejection device 11, if the time that the liquid ejection device 11 has not been used is less than the second hour, a first short-time agitation circulation, which is a weaker agitation operation than the first long-time agitation circulation, is performed.

[0100] Furthermore, after the liquid ejection device 11 is installed, if the liquid level of the humidifying fluid L1 in the humidifying fluid storage section 39 is less than the first height H after printing (print job) is completed, the first agitation circulation is performed for a short time.

[0101] In this way, in the liquid ejection device 11 of this embodiment, an appropriate stirring operation is performed in accordance with the degree of lowering of the liquid level of the humidifying fluid L1 in the humidifying fluid storage unit 39 due to evaporation of the moisture L2. In this case, whether the stirring operation is the first stirring circulation (long-term first stirring circulation and short-term first stirring circulation) or the second stirring circulation, the humidifying fluid L1 that has flowed through the recovery passage 41, the moisture L2 from the moisture storage unit 57, and air are sent from one end 41a of the recovery passage 41 into the humidifying fluid L1 in the humidifying fluid storage unit 39.

[0102] Therefore, regardless of the amount of evaporation of the moisture L2 from the humidifying fluid L1 in the humidifying fluid storage portion 39, the moisture L2 is supplied to the humidifying fluid L1 in the humidifying fluid storage portion 39, and the inside of the humidifying fluid storage portion 39 is efficiently stirred. Therefore, the humidifying fluid L1 in the humidifying fluid storage portion 39 and the moisture L2 supplied into the humidifying fluid storage portion 39 are mixed sufficiently and effectively.

[0103] <Effects of this embodiment> According to the embodiment described above in detail, the following effects are achieved. (1) In the liquid ejection device 11, one end 41a of the recovery flow path 41 opens at a position lower than the liquid level of the humidifying fluid L1 in the humidifying fluid storage unit 39. As the first agitation circulation, the control unit 77 supplies moisture L2 into the circulation path 42 using the moisture supply unit 56 and drives the second pump 53 to cause the humidifying fluid L1 to flow in the circulation path 42.

[0104] According to this configuration, by performing the first agitation circulation, even if the moisture L2 in the humidification fluid L1 evaporates, it is possible to efficiently agitate the humidification fluid L1 and the moisture L2 supplied from the moisture supply unit 56. Therefore, it is possible to sufficiently mix the humidification fluid L1 and the moisture L2 supplied from the moisture supply unit 56.

[0105] (2) The liquid discharger 11 includes a first pump 52 that can reduce the pressure in the space inside the humidifying fluid storage unit 39. As the second agitation circulation, the control unit 77 supplies moisture L2 into the circulation path 42 using the moisture supply unit 56 and drives the second pump 53 and the first pump 52 to cause the humidifying fluid L1 to flow within the circulation path 42.

[0106] According to this configuration, by performing the second agitation circulation, it is possible to agitate in a short time the humidifying fluid L1 and the moisture L2 supplied from the moisture supply unit 56. In other words, it is possible to shorten the agitation time required to mix the humidifying fluid L1 and the moisture L2 supplied from the moisture supply unit 56.

[0107] (3) In the liquid ejection device 11, the control unit 77 performs a second agitation circulation by driving the first pump 52 while keeping the closed space forming unit 31 connected to the atmosphere, thereby agitating the humidifying fluid storage unit 39 with air.

[0108] According to this configuration, the air bubbles can efficiently agitate the inside of the humidifying fluid container 39 . (4) The liquid ejector 11 includes a detection unit 46 that can detect the height of the liquid surface in the humidifying fluid storage unit 39. When the liquid ejector 11 is installed, the control unit 77 performs a first agitation circulation when the height of the liquid surface is equal to or greater than a first height H, and performs a second agitation circulation when the height of the liquid surface is less than the first height H.

[0109] According to this configuration, it is possible to perform an appropriate stirring operation in accordance with the degree of lowering of the liquid level in the humidifying fluid container 39 due to evaporation of the water L2. (5) The liquid ejector 11 includes a timer 82 that measures the unused time, which is the time during which the liquid ejector 11 is not in use. After the liquid ejector 11 is installed, the control unit 77 performs the second agitation circulation when the unused time is equal to or longer than a first hour, performs the long-time first agitation circulation with a long agitation time when the unused time is equal to or longer than the second hour but less than the first hour, and performs the short-time first agitation circulation with a short agitation time when the unused time is less than the second hour.

[0110] According to this configuration, it is possible to perform an appropriate stirring operation in accordance with the length of time that the liquid ejection device 11 has not been used, which is related to the amount of evaporation of the water L2. (Example of change) The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0111] The timer 82 may be omitted. The detection unit 46 may be omitted. The maintenance device 26 may be provided in a liquid ejection device that ejects liquid from the liquid ejection head 18 toward the medium M in the vertical direction.

[0112] The maintenance device 26 may be provided in a liquid ejection device that is a serial inkjet printer that performs printing by ejecting liquid onto a medium M using a liquid ejection head supported by a carriage that moves back and forth in the width direction X.

[0113] In the maintenance device 26, the water supply unit 56 may be disposed in the recovery passage 41. In this case, the second pump 53 may also be disposed in the recovery passage 41. The maintenance device 26 may be configured to be able to replenish the water L2 in the water storage section 57.

[0114] The maintenance device 26 may be configured so that the humidifying fluid container 39 is replaceable. In the liquid ejection device 11, the short-term first agitation circulation may be performed periodically, for example, once a day or once every two days, regardless of the height of the liquid surface in the humidifying fluid storage section 39 or the length of time the liquid ejection device 11 has not been used, or it may be performed irregularly.

[0115] 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 solid functional material particles, 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 ejects 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, and the like used in optical communication elements. The liquid ejection device may also be a device that ejects etching liquids such as acids or alkalis to etch substrates, etc.

[0116] The technical concepts and effects that can be understood from the above-described embodiment and modified examples will be described below. (A) A liquid ejection device includes a liquid ejection head capable of ejecting liquid from a nozzle, a closed space forming portion capable of forming a closed space in which the nozzle opens upon contact with the liquid ejection head, a cap having an inlet through which humidifying fluid flows to humidify the closed space and an outlet through which the humidifying fluid flows, a humidifying fluid storage portion that stores the humidifying fluid, a supply flow path that connects the humidifying fluid storage portion to the inlet, a recovery flow path that connects the humidifying fluid storage portion to the outlet, a pump that can cause the humidifying fluid to flow within a circulation path that includes the humidifying fluid storage portion, the supply flow path, and the recovery flow path, a water supply portion that can supply water into the circulation path, and a control portion, one end of the recovery flow path opens at a position lower than the liquid level of the humidifying fluid in the humidifying fluid storage portion, and the control portion, as a first agitation circulation, supplies water into the circulation path using the water supply portion and drives the pump to cause the humidifying fluid to flow within the circulation path.

[0117] With this configuration, by performing the first agitation circulation, even if the moisture in the humidification fluid evaporates, the humidification fluid and the water supplied from the water supply unit can be efficiently agitated, thereby allowing the humidification fluid and the water supplied from the water supply unit to be sufficiently mixed together.

[0118] (B) The liquid ejection device may include a pressure reducing unit capable of reducing the pressure in the space within the humidifying fluid storage unit, and the control unit may supply water into the circulation path using the water supply unit as a second agitation circulation, and drive the pump and the pressure reducing unit to cause the humidifying fluid to flow within the circulation path.

[0119] According to this configuration, by performing the second agitation circulation, the humidification fluid and the water supplied from the water supply unit can be agitated in a short time, that is, the agitation time required to mix the humidification fluid and the water supplied from the water supply unit can be shortened.

[0120] (C) In the liquid ejection device, the control unit may perform the second agitation circulation by driving the pressure reducing unit while the closed space forming unit is connected to the atmosphere, thereby agitating the humidifying fluid storage unit with air.

[0121] According to this configuration, the air bubbles can efficiently agitate the inside of the humidifying fluid container. (D) The liquid ejection device may include a detection unit capable of detecting the height of the liquid surface in the humidifying fluid storage unit, and when the liquid ejection device is installed, the control unit may perform the first agitation circulation when the height of the liquid surface is equal to or greater than a first height, and may perform the second agitation circulation when the height of the liquid surface is less than the first height.

[0122] With this configuration, it is possible to perform an appropriate stirring operation in accordance with the degree of lowering of the liquid level in the humidifying fluid container due to evaporation. (E) The liquid ejection device may include a measuring unit that measures unused time, which is the time during which the liquid ejection device is not in use, and after installation of the liquid ejection device, the control unit may perform the second agitation circulation when the unused time is a first hour or more, perform the first agitation circulation with a long agitation time when the unused time is a second hour or more but less than the first hour, and perform the first agitation circulation with a short agitation time when the unused time is less than the second hour.

[0123] According to this configuration, it is possible to perform an appropriate stirring operation according to the length of time that the liquid ejection device has not been used, which is related to evaporation. (F) A stirring method for a liquid ejection device includes a liquid ejection head capable of ejecting liquid from a nozzle, a closed space forming portion capable of forming a closed space in which the nozzle opens upon contact with the liquid ejection head, a cap having an inlet through which humidifying fluid flows to humidify the closed space and an outlet through which the humidifying fluid flows, a humidifying fluid storage portion that stores the humidifying fluid, a supply flow path connecting the humidifying fluid storage portion to the inlet, a recovery flow path connecting the humidifying fluid storage portion to the outlet, a pump that can cause the humidifying fluid to flow within a circulation path including the humidifying fluid storage portion, the supply flow path, and the recovery flow path, and a water supply portion that can supply water into the circulation path, wherein one end of the recovery flow path opens at a position lower than the liquid level of the humidifying fluid within the humidifying fluid storage portion, and a first stirring circulation is performed in which the water supply portion supplies water into the circulation path and the pump is driven to cause the humidifying fluid to flow within the circulation path.

[0124] With this configuration, by performing the first agitation circulation, even if the moisture in the humidification fluid evaporates, the humidification fluid and the water supplied from the water supply unit can be efficiently agitated, thereby allowing the humidification fluid and the water supplied from the water supply unit to be sufficiently mixed together.

[0125] (G) In the stirring method for a liquid ejection device, a pressure reducing unit capable of reducing the pressure in the space within the humidifying fluid storage unit may be provided, and a second stirring circulation may be performed in which water is supplied into the circulation path by the water supply unit and the pump and the pressure reducing unit are driven to cause the humidifying fluid to flow within the circulation path.

[0126] According to this configuration, by performing the second agitation circulation, the humidification fluid and the water supplied from the water supply unit can be agitated in a short time, that is, the agitation time required to mix the humidification fluid and the water supplied from the water supply unit can be shortened.

[0127] (H) In the stirring method for a liquid ejection device, the second stirring circulation may include driving the pressure reducing section while the closed space forming section is connected to the atmosphere, thereby stirring the humidifying fluid storage section with air.

[0128] According to this configuration, the air bubbles can efficiently agitate the inside of the humidifying fluid container. (I) In a stirring method for a liquid ejection device, a detection unit capable of detecting the height of the liquid surface in the humidifying fluid storage section may be provided, and when the liquid ejection device is installed, the first stirring circulation may be performed if the height of the liquid surface is equal to or greater than a first height, and the second stirring circulation may be performed if the height of the liquid surface is less than the first height.

[0129] With this configuration, it is possible to perform an appropriate stirring operation in accordance with the degree of lowering of the liquid level in the humidifying fluid container due to evaporation. (J) A stirring method for a liquid ejection device may include a measuring unit that measures unused time, which is the time during which the liquid ejection device is not in use, and after installation of the liquid ejection device, if the unused time is a first hour or more, the second stirring circulation is performed, if the unused time is a second hour or more but less than the first hour, the first stirring circulation with a longer stirring time is performed, and if the unused time is less than the second hour, the first stirring circulation with a shorter stirring time is performed.

[0130] According to this configuration, it is possible to perform an appropriate stirring operation according to the length of time that the liquid ejection device has not been used, which is related to evaporation. [Explanation of symbols]

[0131] 11...liquid ejection device, 12...main body, 13...image reading unit, 14...automatic feeding unit, 15...operation unit, 16...medium storage unit, 17...printing unit, 18...liquid ejection head, 19...head unit, 20...placing unit, 20a...placing surface, 21...transport path, 22...cap, 23...support unit, 24...nozzle, 25...nozzle surface, 26...maintenance device, 27...head unit moving mechanism, 28...cap moving mechanism, 29...humidified fluid circulation mechanism, 30...waste liquid recovery mechanism, 31...closed space forming unit, 32...humidification chamber, 33...waste liquid storage area, 34...partition wall, 35...first moisture-permeable membrane, 36...atmosphere communication hole, 37...inlet, 38...outlet, 39...humidification fluid storage section, 40...supply flow path, 40a...one end, 41...recovery flow path, 41a...one end, 42...circulation path, 43...upper wall, 44...circumferential wall, 45...bottom wall, 46...detection section, 47...first electrode, 48...second electrode, 49...first atmosphere communication passage, 50...second moisture-permeable membrane, 51...first on-off valve, 52...first pump (pressure reduction section), 53...second pump (pump), 54... First check valve, 55...pressure adjustment valve, 56...moisture supply section (water supply section), 57...moisture storage section, 58...moisture supply flow path, 59...second on-off valve, 60...second check valve, 61...outlet section, 62...first junction section, 63...pressurized air supply section, 64...pressurized air supply path, 65...third on-off valve, 66...third pump, 67...waste liquid recovery path, 68...fourth pump, 69...buffer chamber, 70...fifth pump, 71...second atmosphere communication path, 72...waste liquid storage section, 73...discharge hole, 74...atmospheric release mechanism, 75...third atmosphere Connecting passage, 76...fourth on-off valve, 77...control unit, 78...detector group, 79...interface unit, 80...CPU, 81...memory, 82...timer (measurement unit), 83...control circuit, 84...drive circuit, 85...computer, θ1...angle, D1...first direction, D2...second direction, D3...third direction, D4...fourth direction, H...first height, L1...humidifying fluid, L2...moisture (water), L3...waste liquid, M...medium, X...width direction, Y...depth direction, Y1...discharge direction, Z...vertical direction, Z1...conveying direction.

Claims

1. a liquid ejection head capable of ejecting liquid from a nozzle; a cap having a closed space forming portion that can form a closed space in which the nozzle opens by contacting the liquid ejection head, an inlet through which humidifying fluid flows in to humidify the closed space, and an outlet through which the humidifying fluid flows out; a humidifying fluid storage section that stores the humidifying fluid; a supply flow path that communicates the humidifying fluid storage portion with the inlet; a recovery flow path that connects the humidifying fluid storage portion and the outlet; a pump capable of causing the humidifying fluid to flow in a circulation path including the humidifying fluid storage portion, the supply flow path, and the recovery flow path; a water supply unit capable of supplying water into the circulation path; A control unit; Equipped with one end of the recovery flow path opens at a position lower than the liquid level of the humidifying fluid in the humidifying fluid storage section, The liquid ejection device, wherein the control unit supplies water into the circulation path by the water supply unit and drives the pump to circulate the humidifying fluid within the circulation path as a first agitation circulation.

2. a pressure reducing unit capable of reducing the pressure in the space within the humidifying fluid containing unit; The liquid ejection device according to claim 1, characterized in that, as a second agitation circulation, the control unit supplies water into the circulation path using the water supply unit and drives the pump and the pressure reduction unit to circulate the humidifying fluid within the circulation path.

3. The liquid ejection device described in claim 2, characterized in that the control unit, as the second stirring circulation, drives the pressure reducing unit while keeping the closed space forming unit connected to the atmosphere, thereby stirring the humidifying fluid storage unit with air.

4. a detection unit capable of detecting the height of the liquid surface in the humidifying fluid storage unit; When the liquid ejection device is installed, the control unit When the height of the liquid surface is equal to or higher than a first height, the first agitation circulation is performed; The liquid ejection device according to claim 3 , wherein the second agitation and circulation is performed when the height of the liquid surface is less than a first height.

5. a measuring unit that measures an unused time, which is a time when the liquid ejection device is not in use; After the liquid ejection device is installed, the control unit When the unused time is equal to or longer than a first hour, the second agitation circulation is performed; When the unused time is equal to or longer than the second time and shorter than the first time, the first agitation circulation is performed with a longer agitation time; 5. The liquid ejection apparatus according to claim 3, wherein the first agitation circulation with a shorter agitation time is performed when the unused time is less than the second time.

6. a liquid ejection head capable of ejecting liquid from a nozzle; a cap having a closed space forming portion that can form a closed space in which the nozzle opens by contacting the liquid ejection head, an inlet through which humidifying fluid flows in to humidify the closed space, and an outlet through which the humidifying fluid flows out; a humidifying fluid storage section that stores the humidifying fluid; a supply flow path that communicates the humidifying fluid storage portion with the inlet; a recovery flow path that connects the humidifying fluid storage portion and the outlet; a pump capable of causing the humidifying fluid to flow in a circulation path including the humidifying fluid storage portion, the supply flow path, and the recovery flow path; a water supply unit capable of supplying water into the circulation path; Equipped with a liquid ejection device, wherein one end of the recovery passage is open at a position lower than a liquid level of the humidifying fluid in the humidifying fluid storage section, a first agitation circulation method for a liquid ejection device, the method comprising: supplying water into the circulation path by the water supply unit; and driving the pump to cause the humidifying fluid to flow within the circulation path;

7. a pressure reducing unit capable of reducing the pressure in the space within the humidifying fluid containing unit; The stirring method for a liquid ejection device according to claim 6, characterized in that a second stirring circulation is performed by supplying water into the circulation path using the water supply unit and driving the pump and the pressure reducing unit to flow the humidifying fluid within the circulation path.

8. The stirring method for a liquid ejection device described in claim 7, characterized in that the second stirring circulation includes stirring the humidifying fluid storage section with air by driving the pressure reducing section while the closed space forming section is connected to the atmosphere.

9. a detection unit capable of detecting the height of the liquid surface in the humidifying fluid storage unit; When the liquid ejection device is installed, When the height of the liquid surface is equal to or higher than a first height, the first agitation circulation is performed; 9. The agitation method for a liquid ejection device according to claim 8, wherein the second agitation circulation is performed when the height of the liquid surface is less than a first height.

10. a measuring unit that measures an unused time, which is a time when the liquid ejection device is not in use; After the liquid ejection device is installed, When the unused time is equal to or longer than a first hour, the second agitation circulation is performed; When the unused time is equal to or longer than the second time and shorter than the first time, the first agitation circulation is performed with a longer agitation time; 10. The agitation method for a liquid ejection apparatus according to claim 8, wherein the first agitation circulation with a shorter agitation time is performed when the unused time is less than the second time.

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