LIQUID EJECTION APPARATUS AND METHOD FOR CONTROLLING LIQUID EJECTION APPARATUS - Patent application

Abstract

To provide a liquid discharge device having a simplified configuration for discharging waste liquid and a control method of the same.SOLUTION: The liquid discharge device comprises: a liquid discharge head 13a; a supply passage 90; a supply pump 44; a cap 83; a discharge passage 85 for discharging waste liquid received by the cap 83; a suction valve 86 that opens and closes the discharge passage 85; a pressure chamber 111 arranged closer to a downstream than the suction valve 86; a cleaning pump 116 that depressurizes the inside of the pressure chamber 111; a pressurization passage 127 that is communicated with the supply pump 44 and the pressure chamber 111; a pressurization valve 128 that opens and closes the pressurization passage 127; a discharge valve 112 that opens and closes the discharge passage 85 at a downstream of the pressure chamber 111; and a control part 100. The supply pump 44 is configured to pressurize the inside of the pressure chamber 111 through the pressurization passage 127.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a liquid ejection device that ejects liquid onto a medium and a method for controlling the liquid ejection device. [Background technology]

[0002] Patent Document 1 discloses an inkjet recording apparatus, which is an example of a liquid ejection apparatus, including a plurality of pumps, such as a pressure pump for pressure cleaning, a diaphragm pump for suction cleaning, and a suction pump for discharging waste liquid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-162804 A Summary of the Invention [Problem to be solved by the invention]

[0004] The structure of the liquid ejection device becomes more complicated as more pumps are added depending on the application. [Means for solving the problem]

[0005] a control unit configured to control the supply pump, the cleaning pump, the suction valve, and the pressurization valve, and the supply pump configured to pressurize the liquid in the liquid container or in the supply flow path; a cap configured to define a closed space into which the nozzle opens; a discharge flow path for discharging waste liquid, which is the liquid received in the cap, from the cap; a suction valve arranged in the middle of the discharge flow path, the suction valve arranged to open and close the discharge flow path; a pressure chamber arranged in the middle of the discharge flow path, the pressure chamber arranged downstream of the suction valve; a cleaning pump configured to reduce the pressure inside the pressure chamber; a pressurization flow path communicating with the supply pump and the pressure chamber, a pressurization valve arranged to open and close the pressurization flow path; a discharge valve arranged in the middle of the discharge flow path, the discharge valve arranged to open and close the discharge flow path downstream of the pressure chamber;

[0006] A liquid ejection device that solves the above problem includes a liquid ejection head having a nozzle capable of ejecting liquid, a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head, a supply pump configured to pressurize the liquid in the liquid container or in the supply flow path, a cap configured to define a closed space into which the nozzle opens, a discharge flow path for discharging waste liquid, which is the liquid received in the cap, from the cap, a suction valve arranged midway through the discharge flow path, the suction valve configured to open and close the discharge flow path, and a pressure chamber arranged midway through the discharge flow path, the supply pump is configured to pressurize the pressure chamber through the pressurized flow path, a pressurization valve configured to open and close the pressurized flow path, a pressure reduction flow path communicating with the supply pump and the pressure chamber, a pressure reduction valve configured to open and close the pressure reduction flow path, a discharge valve disposed midway through the discharge flow path, the discharge valve configured to open and close the discharge flow path downstream of the pressure chamber, and a control unit configured to control the supply pump, the suction valve, the pressurization valve, and the pressure reduction valve,

[0007] A liquid ejection device that solves the above problem includes a liquid ejection head having a nozzle capable of ejecting liquid, a supply flow path for flowing liquid in a liquid container toward the liquid ejection head, a cap configured to define a closed space into which the nozzle opens, a discharge flow path for discharging waste liquid, which is the liquid received in the cap, from the cap, a suction valve configured to open and close the discharge flow path, a pressure chamber arranged in the middle of the discharge flow path, the pressure chamber arranged downstream of the suction valve, a cleaning pump configured to reduce the pressure inside the pressure chamber, a pressurized flow path communicating with the cleaning pump and the pressure chamber, a pressurized valve configured to open and close the pressurized flow path, a discharge valve arranged in the middle of the discharge flow path, the discharge valve configured to open and close the discharge flow path downstream of the pressure chamber, and a control unit configured to control the cleaning pump, the suction valve, and the pressurized valve, and the cleaning pump is configured to pressurize the pressure chamber through the pressurized flow path.

[0008] In a control method for a liquid ejection device that solves the above-mentioned problems, the liquid ejection device includes a liquid ejection head having a nozzle capable of ejecting liquid, a supply flow path for flowing liquid in a liquid container toward the liquid ejection head, a supply pump configured to pressurize the liquid in the liquid container or in the supply flow path, a cap configured to define a closed space into which the nozzle opens, a discharge flow path for discharging waste liquid, which is the liquid received in the cap, from the cap, a suction valve arranged in the middle of the discharge flow path, the suction valve configured to open and close the discharge flow path, a pressure chamber arranged in the middle of the discharge flow path, the pressure chamber arranged downstream of the suction valve, a cleaning pump configured to reduce the pressure inside the pressure chamber, a pressurization flow path communicating with the supply pump and the pressure chamber, a pressurization valve configured to open and close the pressurization flow path, and a discharge valve arranged in the middle of the discharge flow path, the discharge valve configured to open and close the discharge flow path downstream of the pressure chamber. The method includes opening the pressurization valve, and discharging the waste liquid from the pressure chamber by driving the supply pump while the pressurization valve is open to pressurize the pressure chamber through the pressurization flow path.

[0009] a pressure chamber disposed in the middle of the discharge flow path and disposed downstream of the suction valve; a pressurized flow path communicating with the supply pump and the pressure chamber; a pressure reduction flow path communicating with the supply pump and the pressure chamber; a pressure reduction valve configured to open and close the pressurized flow path; and a discharge valve disposed in the middle of the discharge flow path and configured to open and close the pressurized flow path. The method includes opening the pressurization valve, and discharging the waste liquid from the pressure chamber by driving the supply pump while the pressurization valve is open to pressurize the pressure chamber through the pressurization flow path.

[0010] In a method for controlling a liquid ejection device that solves the above-mentioned problems, the liquid ejection device includes a liquid ejection head having a nozzle capable of ejecting liquid, a supply flow path for flowing liquid in a liquid container toward the liquid ejection head, a cap configured to define a closed space in which the nozzle opens, a discharge flow path for discharging waste liquid, which is the liquid received in the cap, from the cap, a suction valve configured to open and close the discharge flow path, a pressure chamber arranged in the middle of the discharge flow path and downstream of the suction valve, a cleaning pump configured to reduce the pressure inside the pressure chamber, a pressurization flow path communicating with the cleaning pump and the pressure chamber, a pressurization valve configured to open and close the pressurization flow path, and a discharge valve arranged in the middle of the discharge flow path and configured to open and close the discharge flow path downstream of the pressure chamber. The method includes opening the pressurization valve, and discharging the waste liquid from the pressure chamber by driving the cleaning pump with the pressurization valve open to pressurize the pressure chamber through the pressurization flow path. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view showing a liquid ejection device according to a first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing a schematic configuration of the liquid ejection device in FIG. [Diagram 3] 3 is a schematic diagram showing a state where cleaning is performed in the liquid ejection apparatus of FIG. 2. [Figure 4] 3 is a schematic diagram showing a state where pressurized wiping is performed in the liquid ejection device of FIG. 2; [Diagram 5] 3 is a schematic diagram of a liquid pressure adjusting mechanism and a valve opening mechanism included in the liquid ejection device of FIG. 2. [Figure 6] 3 is a schematic diagram showing a schematic configuration of a suction mechanism included in the liquid ejection device of FIG. 2. [Figure 7] FIG. 3 is a block diagram of the liquid ejection device in FIG. 2. [Figure 8] FIG. 11 is a schematic diagram showing a schematic configuration of a suction mechanism of a liquid ejection device according to a second embodiment. [Figure 9] FIG. 13 is a schematic diagram showing a schematic configuration of a suction mechanism of a liquid ejection device according to a third embodiment. [Figure 10] 5A to 5C are schematic diagrams showing modified examples of the liquid ejection device according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, with reference to the drawings, a description will be given of first to third embodiments relating to a liquid ejection device 11 and a control method for the liquid ejection device 11. The liquid ejection device 11 is, for example, an inkjet printer that ejects ink, which is an example of a liquid, onto a medium M such as paper to perform recording.

[0013] (First embodiment) <Configuration of the liquid ejection device> 1, the liquid ejection device 11 includes a generally rectangular parallelepiped main body 102, an image reading unit 103, and an automatic feed unit 104. The image reading unit 103 is attached on the main body 102. The automatic feed unit 104 is attached on the image reading unit 103.

[0014] The image reading unit 103 is configured to read images, such as characters and photographs, recorded on an original. The automatic feeding unit 104 is configured to feed the original toward the image reading unit 103. The image reading unit 103 has an operation unit 105. The operation unit 105 has, for example, a touch panel type liquid crystal screen and operation buttons. A user operates the operation unit 105 to give instructions to the liquid ejection device 11.

[0015] The main body unit 102 has one or more medium storage units 106 capable of storing multiple media, for example multiple sheets of paper. In one example, the main body unit 102 has four medium storage units 106. The medium storage units 106 are stored in the main body unit 102 so as to be removable. The main body unit 102 has a placement unit 107 on its upper portion. The placement unit 107 has a placement surface 107a on which the medium on which recording has been performed is placed.

[0016] The medium contained in the medium containing section 106 is transported to the mounting section 107 by a feed roller (not shown). More specifically, the feed roller rotates while in contact with the topmost medium of the multiple media contained in the medium containing section 106. This causes the topmost medium to be sent out from the medium containing section 106 to above the medium containing section 106. The liquid ejection head 13a (see FIG. 2) ejects liquid toward the medium being transported. Recording is performed by the ejected liquid adhering to the medium. After recording, the medium is ejected toward the mounting section 107 by one or more ejection rollers (not shown).

[0017] As shown in FIG. 2, the liquid ejection device 11 includes a liquid ejection section 13, a liquid storage section 20, a storage section 25, a supply mechanism 40, a pressure adjustment section 50, a supply restriction section 60, a liquid pressurization section 70, a maintenance section 80, and a control section 100. The liquid storage section 20 stores the liquid to be supplied to the liquid ejection section 13. The storage section 25 temporarily stores the liquid to be supplied from the liquid storage section 20 to the liquid ejection section 13. The supply mechanism 40 is configured to send air to the liquid storage section 20, the supply restriction section 60, and the liquid pressurization section 70. The pressure adjustment section 50 is configured to adjust the pressure of the liquid supplied from the liquid storage section 20 to the liquid ejection section 13. The supply restriction section 60 is configured to restrict the supply of the liquid from the liquid storage section 20 to the liquid ejection section 13. The liquid pressurization section 70 is configured to pressurize the liquid supplied to the liquid ejection section 13. The maintenance section 80 is configured to perform maintenance of the liquid ejection section 13. The control unit 100 is configured to control various components of the liquid ejection device 11 .

[0018] The liquid ejection device 11 includes a plurality of supply flow paths 90 through which the liquid flows. The plurality of supply flow paths 90 include a first supply flow path 91, a second supply flow path 92, a third supply flow path 93, a fourth supply flow path 94, and a fifth supply flow path 95. The first supply flow path 91 connects the liquid storage section 20 and the storage section 25. The second supply flow path 92 connects the storage section 25 and the pressure adjustment section 50. The third supply flow path 93 connects the pressure adjustment section 50 and the supply restriction section 60. The fourth supply flow path 94 connects the supply restriction section 60 and the liquid pressurizing section 70. The fifth supply flow path 95 connects the liquid pressurizing section 70 and the liquid ejection section 13. The liquid stored in the liquid storage section 20 is supplied to the liquid ejection section 13 through these supply flow paths 91 to 95. In the following description, in these supply passages, the side where the first supply passage 91 exists will be referred to as the upstream side, and the side where the fifth supply passage 95 exists will be referred to as the downstream side.

[0019] The liquid ejection unit 13 has one or more liquid ejection heads 13a capable of ejecting liquid. Each liquid ejection head 13a has a nozzle surface 12a in which one or more nozzles 12 are opened. A fifth supply flow path 95 branches off and is connected to each liquid ejection head 13a.

[0020] The liquid ejection head 13a ejects liquid from a plurality of nozzles 12 toward the medium M. For example, the liquid ejection unit 13 includes, for each nozzle 12 of the liquid ejection head 13a, a cavity that stores liquid, a vibration plate that forms part of the cavity, and a piezoelectric element attached to the vibration plate. The volume of the cavity is changed by vibrating the vibration plate by driving the piezoelectric elements, and liquid is ejected from the nozzles 12. Characters and images are recorded on the medium M by ejecting the liquid onto the medium M.

[0021] The liquid storage section 20 includes a liquid storage body 14 that is compressed and deformed in response to an external force. The liquid storage body 14 is, for example, a bag formed of a flexible film member. The liquid storage body 14 has a supply port that communicates with the upstream end of the first supply flow path 91. The liquid storage section 20 includes a storage container 21 that stores the liquid storage body 14. The storage container 21 is a sealed container to which the upstream end of the first supply flow path 91 is connected. When gas flows into the storage container 21 through the first delivery flow path 41, the pressure inside the storage container 21 increases. When the inside of the storage container 21 is pressurized in this manner, the liquid storage body 14 is compressed and deformed. As a result, the liquid stored in the liquid storage body 14 is pressurized and supplied downstream. Details of the configuration around the liquid storage section 20, including the storage section 25 that temporarily stores the liquid supplied from the liquid storage section 20 to the liquid discharge section 13, will be described later.

[0022] The supply mechanism 40 includes a supply pump 44 and a delivery flow path 47. The delivery flow path 47 may include a plurality of branch flow paths, for example, a first delivery flow path 41, a second delivery flow path 42, and a third delivery flow path 43. The supply pump 44 is, for example, a compression pump that compresses and delivers air. The first delivery flow path 41 connects the supply mechanism 40 and the liquid storage section 20. The second delivery flow path 42 connects the first delivery flow path 41 and the supply restriction section 60. The third delivery flow path 43 connects the second delivery flow path 42 and the liquid pressurizing section 70. The delivery flow path 47, the first delivery flow path 41, the second delivery flow path 42, and the third delivery flow path 43 are flow paths through which gas can flow. In addition, since gas flows from the supply pump 44 toward the liquid storage section 20, the supply regulation section 60, and the liquid pressurization section 70, in the following explanation, the side where the supply pump 44 is located will be referred to as the upstream side, and the side where the liquid storage section 20, the supply regulation section 60, and the liquid pressurization section 70 are located will be referred to as the downstream side.

[0023] The supply mechanism 40 includes a third delivery valve 45 and a fourth delivery valve 46. The third delivery valve 45 allows the flow of gas from the supply pump 44 to the supply restriction unit 60 through the second delivery flow path 42 when the valve is open, and restricts the flow of gas from the supply pump 44 to the supply restriction unit 60 when the valve is closed. The fourth delivery valve 46 allows the flow of gas from the supply pump 44 to the liquid pressurizing unit 70 through the third delivery flow path 43 when the valve is open, and restricts the flow of gas from the supply pump 44 to the liquid pressurizing unit 70 when the valve is closed. The supply mechanism 40 delivers gas to the supply restriction unit 60 and the liquid pressurizing unit 70 through the second delivery flow path 42 and the third delivery flow path 43 depending on the open / closed states of the third delivery valve 45 and the fourth delivery valve 46. Opening a valve is referred to as opening a valve, and closing a valve is referred to as closing a valve.

[0024] When the pressure of the liquid in the third supply flow path 93 communicating with the liquid ejection head 13a falls below a predetermined pressure lower than atmospheric pressure as a result of liquid being ejected from the liquid ejection head 13a, the pressure adjustment unit 50 communicates between the second supply flow path 92 and the third supply flow path 93. On the other hand, by communicating between the second supply flow path 92 and the third supply flow path 93, the pressure adjustment unit 50 disconnects the second supply flow path 92 from the third supply flow path 93 when the pressure of the liquid in the third supply flow path 93 becomes equal to or higher than the predetermined pressure.

[0025] The pressure adjusting unit 50 adjusts the pressure of the liquid supplied to the liquid ejection head 13a to a predetermined pressure or less. In one example, the pressure adjusting unit 50 adjusts the pressure of the liquid upstream of the pressure adjusting unit 50 to atmospheric pressure or more, for example, about 20 Pa, and adjusts the pressure of the liquid downstream of the pressure adjusting unit 50 to less than atmospheric pressure, for example, about -1 kPa.

[0026] Each liquid ejection head 13a has a plurality of pressure adjustment units 50 provided for each type of liquid. For example, when four types of liquid are supplied to each liquid ejection head 13a, four pressure adjustment units 50 are provided for each type of liquid in one liquid ejection head 13a.

[0027] 2, the supply restriction section 60 is formed with a gas chamber 61 capable of storing a gas, a liquid chamber 62 capable of storing a liquid, and a protrusion 63 formed within the liquid chamber 62 protruding in a direction from the liquid chamber 62 toward the gas chamber 61. The supply restriction section 60 includes a film member 64, a biasing member 65, and a first release valve 66. The film member 64 separates the gas chamber 61 and the liquid chamber 62. The biasing member 65 biases the film member 64 within the liquid chamber 62 in a direction that increases the volume of the liquid chamber 62. The first release valve 66 opens the liquid chamber 62 to the atmosphere when opened.

[0028] The gas chamber 61 communicates with the downstream end of the second delivery flow path 42, and the liquid chamber 62 communicates with the downstream end of the third supply flow path 93 and the upstream end of the fourth supply flow path 94. The upstream end of the fourth supply flow path 94 communicates with the liquid chamber 62 via an opening 67 of the protruding portion 63. The film member 64 is flexible and displaces in a direction to increase or decrease the volumes of the gas chamber 61 and the liquid chamber 62 according to the pressure difference between the gas chamber 61 and the liquid chamber 62. The film member 64 is also configured to be able to close the opening 67 of the protruding portion 63. The first release valve 66 communicates the gas chamber 61 with the atmosphere when open, and does not communicate the gas chamber 61 with the atmosphere when closed. In other words, when the film member 64 is positioned as shown in Figure 2, the opening 67 of the protrusion 63 is opened by the biasing force of the biasing member 65, allowing liquid to be supplied from the third supply flow path 93 to the fourth supply flow path 94.

[0029] 2, the liquid pressurizing unit 70 has a gas chamber 71 capable of storing a gas, and a liquid chamber 72 capable of storing a liquid. The liquid pressurizing unit 70 includes a film member 73, a biasing member 74, and a second release valve 75. The film member 73 separates the gas chamber 71 from the liquid chamber 72. The biasing member 74 biases the film member 73 in a direction that increases the volume of the liquid chamber 72 within the liquid chamber 72. The second release valve 75 opens the liquid chamber 72 to the atmosphere when opened.

[0030] The gas chamber 71 communicates with the downstream end of the third delivery flow path 43, and the liquid chamber 72 communicates with the downstream end of the fourth supply flow path 94 and the upstream end of the fifth supply flow path 95. The film member 73 is flexible and displaces in a direction that increases or decreases the volumes of the gas chamber 71 and the liquid chamber 72 according to the pressure difference between the gas chamber 71 and the liquid chamber 72. In addition, the second release valve 75 communicates the gas chamber 71 with the atmosphere when open, and does not communicate the gas chamber 71 with the atmosphere when closed.

[0031] <Configuration of the liquid container and surrounding area> 2, in the liquid storage section 20, liquid is stored in the liquid storage body 14. This liquid is supplied to the liquid ejection head 13a. A plurality of storage containers 21 are detachably attached to the liquid ejection device 11. Each storage container 21 stores a corresponding liquid storage body 14.

[0032] For example, two storage containers 21 are removably attached to the liquid ejection device 11. These two storage containers 21 store the same type of liquid. Furthermore, storage containers 21 corresponding to other types of liquid may be attached to the liquid ejection device 11. A configuration may be made in which multiple storage containers 21 can be attached for all liquids to be used. Furthermore, the storage containers 21 may be attached to the liquid ejection device 11 so as not to be detachable, and only the liquid container 14 may be detached and replaced.

[0033] The first liquid container 14f and the second liquid container 14s contain the same type of liquid. The supply mechanism 40 pressurizes at least one of the first liquid container 14f and the second liquid container 14s by sending gas to the first supply flow path 91, thereby supplying the liquid contained in the pressurized liquid container toward the downstream pressure adjustment unit 50. That is, the supply mechanism 40 can selectively pressurize the first liquid container 14f and the second liquid container 14s. The liquid container 14 selected to be pressurized is called the liquid container 14 to be pressurized. Of the two liquid containers 14, the liquid container 14 that is used first is called the first liquid container 14f, and the liquid container 14 that is used next after the first liquid container 14f is called the second liquid container 14s. Therefore, when the liquid in the first liquid container 14f runs out and the first liquid container 14f is replaced with a new liquid container 14, the second liquid container 14s that is next used becomes the first liquid container 14f, and the new replaced liquid container 14 becomes the second liquid container 14s. In other words, the first liquid container 14f can be read as the second liquid container 14s, and the second liquid container 14s can be read as the first liquid container 14f.

[0034] The first supply flow path 91 includes two outlet flow paths 22 that are individually connected to two liquid containers 14 that contain the same type of liquid, and a junction flow path 23 that connects the two outlet flow paths 22 and the liquid ejection head 13a through a pressure adjustment unit 50. Valves are individually provided in the two outlet flow paths 22. The valve provided in the outlet flow path 22 that is connected to the first liquid container 14f is referred to as a first valve 24f, and the valve provided in the outlet flow path 22 that connects the liquid container 14 to a second liquid container 14s is referred to as a second valve 24s.

[0035] The outlet flow path 22 connected to the first liquid container 14f and the outlet flow path 22 connected to the second liquid container 14s join at a joining point with the joining flow path 23. As a result, the two outlet flow paths 22 form a connecting flow path 26 that connects the first liquid container 14f and the second liquid container 14s. In other words, the first supply flow path 91 includes the connecting flow path 26 and the joining flow path 23 that connects the connecting flow path 26 and the liquid ejection head 13a.

[0036] The first valve 24f is provided in a portion of the connection flow path 26 between the first liquid container 14f and the junction flow path 23, and opens the connection flow path 26 when supplying the liquid in the first liquid container 14f. The second valve 24s is provided in a portion of the connection flow path 26 between the second liquid container 14s and the junction flow path 23, and opens the connection flow path 26 when supplying the liquid in the second liquid container 14s. In this way, the connection flow path 26 is configured to be able to selectively connect the first liquid container 14f and the second liquid container 14s to the junction flow path 23.

[0037] As shown in FIG. 2, the supply mechanism 40 delivers gas to the liquid storage unit 20 through a first delivery flow path 41. The supply mechanism 40 includes the first delivery flow path 41, a delivery valve 29, and a supply pump 44. The first delivery flow path 41 has two gas delivery paths 28. In the first delivery flow path 41, the two gas delivery paths 28 individually communicate the supply mechanism 40 with the internal spaces of the two storage containers 21. This allows the supply pump 44 to deliver gas to the internal spaces of the respective storage containers 21 through the corresponding gas delivery paths 28. Each gas delivery path 28 is provided with a corresponding delivery valve 29. The delivery valve 29 provided in the gas delivery path 28 that communicates with the storage container 21 that contains the first liquid storage body 14f is referred to as a first delivery valve 29f. The delivery valve 29 provided in the gas delivery passage 28 communicating with the storage container 21 that stores the second liquid storage body 14s is referred to as a second delivery valve 29s.

[0038] The supply pump 44 may be provided individually for each storage container 21. As described above, the supply mechanism 40 also delivers gas to the supply restriction unit 60 and the liquid pressurizing unit 70. A supply pump that delivers gas to the storage container 21 may be provided separately from the supply pump 44 that delivers gas to the supply restriction unit 60 and the liquid pressurizing unit 70. That is, individual supply pumps may be provided corresponding to the respective delivery destinations.

[0039] The first delivery valve 29f and the first valve 24f corresponding to the first liquid container 14f are opened, and the second delivery valve 29s and the second valve 24s corresponding to the second liquid container 14s to be used next are closed. When gas is delivered through the gas delivery path 28 by driving the supply pump 44, the gas enters the container 21, and the inside of the container 21 that contains the first liquid container 14f is pressurized. In this manner, the liquid in the first liquid container 14f is selectively delivered to the liquid ejection head 13a.

[0040] Both the first valve 24f and the second valve 24s may be one-way valves that allow the liquid to flow from the upstream side to the downstream side and restrict the liquid to flow from the downstream side to the upstream side. In this case, when the first delivery valve 29f corresponding to the first liquid container 14f is opened and the second delivery valve 29s corresponding to the second liquid container 14s is closed and the supply pump 44 is driven, only the liquid in the first liquid container 14f whose pressure in the container 21 has increased is delivered to the liquid ejection head 13a. The first valve 24f and the second valve 24s may be opening / closing valves that are opened and closed by the control unit 100.

[0041] As shown in FIG. 2, the storage section 25 has a detection section 31, a movable wall 32, a moving body 33, a first biasing member 34, a lever 35, and a second biasing member 36. The moving body 33 moves in accordance with the displacement of the movable wall 32. The first biasing member 34 biases the moving body 33 in a direction approaching the movable wall 32. The lever 35 displaces in accordance with the movement of the moving body 33. The second biasing member 36 biases the lever 35 in a direction approaching the moving body 33. The detection section 31 detects the displacement of the lever 35.

[0042] When the pressure of the liquid in the first supply flow path 91 decreases, the movable wall 32 is displaced toward the inside of the storage section 25, and the moving body 33 is moved in a direction approaching the movable wall 32 by the biasing force of the first biasing member 34. As a result, the lever 35 pressed by the moving body 33 is displaced by the biasing force of the second biasing member 36, and the detection section 31 detects the displacement of the lever 35.

[0043] The storage section 25 is capable of temporarily storing liquid therein, and is provided in the junction flow path 23. When the remaining amount of liquid in the liquid container 14 being used by the liquid ejection head 13a falls below the first threshold QL1, the supply pressure of the liquid in the first supply flow path 91 becomes the pressurization threshold PL, and the detection section 31 detects the displacement of the lever 35. If the value of the first threshold QL1 is set in this manner, the detection section 31 can detect that the remaining amount of liquid in the liquid container 14 has fallen below the first threshold QL1. That is, the storage section 25 includes the detection section 31 capable of detecting the remaining amount of liquid in the liquid container 14 being used by the liquid ejection head 13a by detecting the amount of liquid in the storage section 25. The detection section 31 is configured to detect the remaining amount of liquid in the liquid container 14 being used by the liquid ejection head 13a by detecting the amount of liquid stored in the storage section 25. More specifically, when the liquid ejection head 13a is discharging liquid inside one of the liquid containers 14, the detection unit 31 detects the amount of liquid stored in the storage unit 25, thereby detecting the remaining amount of liquid in that liquid container 14.

[0044] The detection unit 31 is, for example, an optical sensor, and has a light-emitting unit and a light-receiving unit. When the light-receiving unit changes from a state in which it receives light from the light-emitting unit to a state in which the light-receiving unit blocks light from the light-emitting unit, the detection unit 31 detects that the remaining amount of liquid in the liquid container 14 being used by the liquid ejection head 13a has fallen below a first threshold value QL1. The detection unit 31 may be configured to continuously measure the displacement of the lever 35 by using an optical or magnetic linear encoder capable of detecting continuous displacement.

[0045] The storage unit 25 may have a tank having an air opening hole. In this case, the detection unit 31 may detect the amount of liquid in the storage unit 25 by detecting the liquid level of the liquid in the storage unit 25. The detection unit 31 may also be provided in a location other than the storage unit 25. For example, each liquid container 14 may be provided with a detection unit 31 capable of detecting the remaining amount of liquid in the liquid container 14.

[0046] <About the Maintenance Department> 2, the maintenance unit 80 includes a cleaning mechanism 81 and a wiping mechanism 82. In order to prevent or resolve ejection defects caused by clogging of the nozzles 12 or adhesion of foreign matter in the liquid ejection head 13a, a maintenance operation such as flushing, capping, suction cleaning, or wiping is performed under the control of the control unit 100.

[0047] The cleaning mechanism 81 includes a box-shaped cap 83 having an opening, and an elevation mechanism (not shown) that raises and lowers the cap 83. The cap 83 moves relatively between a capping position where the space where the nozzle 12 opens is surrounded and formed as a closed space, and an open position where the space where the nozzle 12 opens is made an open space, by raising and lowering the cap 83.

[0048] Flushing refers to a discharge operation for discharging droplets unrelated to recording from the nozzles 12. Flushing discharges viscous liquid, air bubbles, or foreign matter that may cause discharge defects from the nozzles 12, thereby preventing clogging of the nozzles 12. Flushing is performed by the liquid discharge head 13a discharging droplets from the nozzles 12 toward the inside of the cap 83.

[0049] Capping refers to the operation of placing the cap 83 at the capping position and abutting the liquid ejection head 13a so as to surround the opening of the nozzle 12 when the liquid ejection head 13a is not ejecting liquid. This surrounds and forms a closed space between the liquid ejection head 13a and the nozzle surface 12a where the nozzle 12 opens. Capping suppresses the thickening of the liquid inside the nozzle 12, thereby preventing ejection defects.

[0050] The cleaning mechanism 81 includes a discharge flow path 85 and a plurality of suction valves 86 provided in the discharge flow path 85. The discharge flow path 85 has one downstream end connected to the suction mechanism 84 and a plurality of upstream ends, and each upstream end is connected to a corresponding cap 83. A corresponding suction valve 86 is disposed midway along each of the branched discharge flow paths 85. The suction valves 86 are configured to open and close the discharge flow path 85.

[0051] Suction cleaning refers to an operation in which a suction force is applied to the nozzles 12 of the liquid ejection head 13a to forcibly discharge liquid from the nozzles 12. When the cap 83 is placed at the capping position, the cap 83 defines a closed space CS (see FIG. 3) between the cap 83 and the lower surface side of the liquid ejection head 13a where the nozzles 12 are open. The suction mechanism 84 applies negative pressure to the closed space CS (see FIG. 3). The negative pressure causes the liquid to be sucked and discharged from the nozzles 12, thereby performing suction cleaning.

[0052] The wiping mechanism 82 includes an elastic wiper 88, a wiper support portion 89 that supports the wiper 88, and a moving mechanism (not shown). The moving mechanism is configured to move the wiper support portion 89 in the arrangement direction of the liquid ejection heads 13a.

[0053] Wiping refers to the operation of wiping the nozzle surface 12a with the wiper 88. By wiping, liquid and dirt such as dust adhering to the nozzle surface 12a of the liquid ejection head 13a are removed.

[0054] After the suction cleaning, the liquid inside the liquid ejection head 13a may be pressurized, and then wiping may be performed. Since the liquid inside the liquid ejection head 13a is pressurized, this cleaning is called pressurized cleaning.

[0055] After the suction cleaning, the liquid inside the liquid ejection head 13a is pressurized to perform pressure cleaning. After the pressure cleaning, wiping is performed. The operations of the supply mechanism 40, the supply restriction unit 60, the liquid pressurizing unit 70, and the maintenance unit 80 in the pressure cleaning will be described.

[0056] 3, when there is one or more liquid ejection heads 13a that require suction cleaning, the control unit 100 selectively moves the cap 83 corresponding to the liquid ejection head 13a that requires suction cleaning to the capping position. Then, the control unit 100 selectively performs suction cleaning on the liquid ejection heads 13a that require suction cleaning by driving the suction mechanism 84 for a predetermined period of time.

[0057] The suction mechanism 84 sucks the air in the closed space CS through the discharge flow path 85, so that the closed space CS becomes negative pressure. The nozzle 12 that opens into the closed space CS communicates with the third supply flow path 93 through the fifth supply flow path 95, the liquid chamber 72 of the liquid pressurizing unit 70, the fourth supply flow path 94, and the liquid chamber 62 of the supply regulating unit 60. As a result, the pressure of the third supply flow path 93 becomes less than a predetermined pressure. The pressure adjusting unit 50 communicates the second supply flow path 92 with the third supply flow path 93. Then, the liquid is continuously supplied from the liquid storage unit 20 to the liquid ejection unit 13, and the liquid is discharged from the liquid ejection head 13a that is the target of suction cleaning, as shown in FIG. 3. The liquid discharged from the liquid ejection head 13a is discharged through the cap 83 and the discharge flow path 85.

[0058] The control unit 100 moves all of the caps 83 to the open position. More specifically, since the caps 83 corresponding to the liquid ejection heads 13a that are not the target of suction cleaning are already in the open position, the control unit 100 moves the caps 83 in the capping position to the open position. Note that the caps 83 may be moved to the open position when the pressure in the closed space CS is negative after the driving of the suction mechanism 84 has stopped, or when the pressure in the closed space CS is approximately equal to atmospheric pressure.

[0059] The control unit 100 opens the third delivery valve 45 while keeping the first release valve 66 closed. As a result, gas flows from the supply pump 44 through the second delivery passage 42 into the gas chamber 61 of the supply restriction unit 60 in the direction of the solid arrow shown in Fig. 3, and as the amount of gas flowing into the gas chamber 61 increases, the pressure in the gas chamber 61 gradually increases.

[0060] 4, when the pressure in the gas chamber 61 becomes greater than the pressure in the liquid chamber 62, the film member 64 reduces the volume of the liquid chamber 62 against the biasing force of the biasing member 65. Then, the film member 64 is displaced to the position shown by the solid line in FIG. 4 and closes the opening 67 of the protrusion 63 in the liquid chamber 62. As a result, the third supply flow path 93 and the fourth supply flow path 94 are no longer in communication with each other, and therefore the pressure adjustment unit 50 and the liquid pressurizing unit 70 are no longer in communication with each other. In other words, the supply restriction unit 60 restricts the supply of liquid from the liquid storage unit 20 to the liquid discharge unit 13.

[0061] The control unit 100 opens the fourth delivery valve 46 while closing the second release valve 75. As a result, gas flows from the supply pump 44 through the third delivery passage 43 into the gas chamber 71 of the liquid pressurizing unit 70 in the direction of the solid arrow shown in Fig. 4, and as the amount of gas flowing into the gas chamber 71 increases, the pressure in the gas chamber 71 gradually increases.

[0062] 4, when the pressure in the gas chamber 71 becomes greater than the pressure in the liquid chamber 72, the film member 73 is displaced to the position shown by the solid line in Fig. 4, where the volume of the liquid chamber 72 is reduced against the biasing force of the biasing member 74. As a result, the liquid in the liquid chamber 72 of the liquid pressurizing unit 70, the fourth supply flow path 94, the fifth supply flow path 95, the inside of the liquid ejection head 13a, and the inside of the nozzle 12 is pressurized.

[0063] In the nozzles 12 of all the liquid ejection heads 13a, the liquid pressure in the nozzles 12 becomes higher than the atmospheric pressure, causing the liquid to leak from the nozzles 12 of all the liquid ejection heads 13a. The liquid leaking from the nozzles 12 refers to a state in which the meniscus formed in a concave shape toward the inside of the nozzle 12 is broken, and the liquid spilling out of the nozzle 12 spreads over the nozzle surface 12a. In this state, the control unit 100 drives a moving mechanism (not shown) to perform wiping, which wipes the nozzle surfaces 12a of all the liquid ejection heads 13a with the wiper 88. Since the liquid is caused to leak from the nozzles 12 by pressurization and then wiped away by the wiper 88, this operation is also called pressurized wiping.

[0064] The control unit 100 closes the third delivery valve 45 and opens the first release valve 66. With the inflow of gas from the supply pump 44 to the gas chamber 61 of the supply restriction unit 60 restricted, the gas chamber 61 of the supply restriction unit 60 is opened to the atmosphere, and the pressure of the gas chamber 61 drops to atmospheric pressure. As a result, the film member 64 is displaced in a direction that increases the volume of the liquid chamber 62 by the biasing force of the biasing member 65, and the film member 64 opens the opening 67 of the protruding portion 63 of the liquid chamber 62. Then, the third supply flow path 93 and the fourth supply flow path 94 are communicated, and the pressure adjustment unit 50 and the liquid pressurizing unit 70 are communicated. In other words, the supply of liquid from the liquid storage unit 20 restricted by the supply restriction unit 60 to the liquid discharge unit 13 is permitted. Note that, as the volume of the liquid chamber 62 increases, the liquid flowing into the liquid chamber 62 is supplied from the third supply flow path 93.

[0065] The control unit 100 closes the fourth delivery valve 46 and opens the second release valve 75. With the inflow of gas from the supply pump 44 to the gas chamber 71 of the liquid pressurizing unit 70 restricted, the gas chamber 71 of the liquid pressurizing unit 70 is opened to the atmosphere, and the pressure of the gas chamber 71 drops to atmospheric pressure. As a result, the film member 73 is displaced in a direction that increases the volume of the liquid chamber 72 by the biasing force of the biasing member 74. Then, as the volume of the liquid chamber 72 increases, the liquid flowing into the liquid chamber 72 is supplied from the fourth supply flow path 94. In other words, the liquid is prevented from being supplied from the fifth supply flow path 95. Then, the control unit 100 ends the pressurized cleaning operation.

[0066] The pressure adjusting section 50, the supply restricting section 60, and the liquid pressurizing section 70 may be a liquid pressure adjusting mechanism 280 and a valve opening mechanism 290 shown in Fig. 5. The liquid pressure adjusting mechanism 280 and the valve opening mechanism 290 are provided between the storage section 25 and the liquid ejection head 13a.

[0067] As shown in FIG. 5, the liquid pressure adjustment mechanism 280 is provided integrally with the filter section 220 at a position downstream of the storage section 25. The liquid pressure adjustment mechanism 280 includes an upstream filter chamber 222, a downstream filter chamber 223, a liquid chamber 282, a valve body 283, and a pressure-receiving member 284. The upstream filter chamber 222 communicates with the storage section 25. The downstream filter chamber 223 communicates with the upstream filter chamber 222 via a filter 221 that collects foreign matter. The liquid chamber 282 communicates with the downstream filter chamber 223 via a communication hole 281, and also communicates with the liquid ejection head 13a. The valve body 283 is configured to be able to open and close the communication hole 281. The base end side of the pressure-receiving member 284 is housed in the downstream filter chamber 223, and the tip side is housed in the liquid chamber 282.

[0068] The liquid chamber 282 is configured to be capable of storing liquid. A part of the wall surface of the liquid chamber 282 is formed by a flexible wall 285 that can be flexibly displaced. The valve body 283 may be, for example, an elastic body such as rubber or resin attached to a base end portion of a pressure-receiving member 284 located in the downstream filter chamber 223.

[0069] The liquid pressure adjustment mechanism 280 includes a first pressing member 286 housed in the downstream filter chamber 223, and a second pressing member 287 housed in the liquid chamber 282. The first pressing member 286 presses the valve body 283 in a direction to close the communication hole 281 via the pressure-receiving member 284. The second pressing member 287 presses the pressure-receiving member 284 back toward the flexible wall 285 when the flexible wall 285 presses the pressure-receiving member 284 as a result of the flexible wall 285 being flexibly displaced in a direction to reduce the volume of the liquid chamber 282.

[0070] When the internal pressure of the liquid chamber 282 decreases and the force with which the flexible wall 285 presses the pressure-receiving member 284 exceeds the pressing forces of the first pressing member 286 and the second pressing member 287, the valve body 283 opens the communication hole 281. When the communication hole 281 is opened and liquid flows from the downstream filter chamber 223 into the liquid chamber 282, the internal pressure of the liquid chamber 282 increases. As a result, before the internal pressure of the liquid chamber 282 increases to a positive pressure, the valve body 283 closes the communication hole 281 due to the pressing forces of the first pressing member 286 and the second pressing member 287. In this way, the internal pressure of the liquid chamber 282 is maintained within a negative pressure range according to the pressing forces of the first pressing member 286 and the second pressing member 287.

[0071] The internal pressure of the liquid chamber 282 decreases as the liquid is discharged from the liquid discharge portion 13. The valve body 283 autonomously opens and closes the communication hole 281 in response to the pressure difference between the atmospheric pressure, which is the external pressure of the liquid chamber 282, and the internal pressure of the liquid chamber 282. Therefore, the liquid pressure adjustment mechanism 280 is a differential pressure valve.

[0072] As shown in Fig. 5, the valve-opening mechanism 290 forcibly opens the communication hole 281 to supply liquid to the liquid ejection head 13a shown in Fig. 2. The valve-opening mechanism 290 includes a pressurizing bag 292 and an air vent passage 293. The pressurizing bag 292 is contained in a storage chamber 291 that is partitioned from the liquid chamber 282 by a flexible wall 285. The air vent passage 293 allows gas delivered from the supply pump 44 of the supply mechanism 40 shown in Fig. 2 to flow into the pressurizing bag 292.

[0073] The valve opening mechanism 290 forcibly opens the communication hole 281 by expanding the pressurized bag 292 due to gas flowing in through the ventilation flow path 293, and displacing the flexible wall 285 in a direction that reduces the volume of the liquid chamber 282. The liquid ejection device 11 is configured to be able to perform pressurized cleaning in which liquid leaks from the nozzles 12 of the liquid ejection head 13a by pressurizing and supplying liquid from the liquid storage section 20 shown in FIG. 2 to the liquid ejection head 13a with the communication hole 281 open.

[0074] <How to calculate remaining liquid amount> The liquid contained in the liquid container 14 is supplied to the liquid ejection head 13a by being pressurized. Therefore, the control unit 100 calculates the remaining amount of liquid in the first liquid container 14f based on the amount of liquid discharged from the liquid ejection head 13a when the first liquid container 14f is pressurized. More specifically, the control unit 100 calculates the remaining amount Q3 of liquid in the liquid container 14 based on the amount of liquid contained in the liquid container 14, Q1, and the total amount of liquid discharged, Q2, which is the amount of liquid discharged from the liquid ejection head 13a when the liquid container 14 is pressurized. That is, the remaining amount Q3 of liquid in the liquid container 14 is calculated for each liquid container 14. The control unit 100 calculates the remaining amount Q3 every time liquid is discharged from the liquid ejection head 13a from the start of use of the liquid container 14 until the liquid in the liquid container 14 runs out.

[0075] The capacity Q1 is the amount of liquid contained in an unused liquid container 14. When the capacity of liquid contained in the liquid container 14 is managed at a constant value at the time of shipping of the storage container 21 containing the liquid container 14 or the liquid container 14, that value is the capacity Q1. In other words, the capacity Q1 is the amount of liquid contained in the liquid container 14 when the storage container 21 containing an unused liquid container 14 is attached.

[0076] When the storage container 21 is attached to the liquid ejection device 11, the storage container 21 and the liquid ejection device 11 may be electrically connected. At this time, the control unit 100 may read various information related to the storage container 21 from the IC chip of the storage container 21. If the amount of liquid contained in the liquid container 14 contained in the storage container 21 is stored in the IC chip when the storage container 21 is shipped, the value of the amount may be read from the IC chip and used as the storage amount Q1. In such a case, the control unit 100 manages the storage amount Q1 as an individual value for each storage container 21.

[0077] The total discharge amount Q2 may be calculated based on the amount of liquid discharged from the liquid discharge head 13a. For example, the total discharge amount Q2 is calculated by multiplying the discharge amount Q2p by the number of shots np. That is, the control unit 100 calculates the total discharge amount Q2 by the formula Q2=Q2p×np.

[0078] The discharge amount Q2p is the amount of liquid discharged from the liquid discharge head 13a. More specifically, the discharge amount Q2p is the amount of liquid discharged from one nozzle 12 in one shot. One shot refers to one discharge from one nozzle 12. The control unit 100 manages the discharge amount Q2p as an individual value for each type of liquid. The number of shots np is the total number of times that the liquid in the liquid container 14 has been discharged from one nozzle 12 for all nozzles 12 since the liquid container 14 was attached to the liquid discharge device 11. That is, the number of shots np in the first liquid container 14f is the total number of times that the liquid in the liquid container 14 has been discharged from one nozzle 12 for all nozzles 12 when the first liquid container 14f is pressurized. The number of shots np includes the number of times that the liquid has been discharged to the medium M by recording as well as the number of times that the liquid has been discharged by flushing. The number of shots np is counted for each liquid container 14. That is, the total discharge amount Q2 is calculated for each liquid container 14. When the discharge amount Q2p varies depending on the driving conditions of the actuator of the liquid ejection head 13a or environmental conditions such as temperature and humidity, the discharge amount Q2p may be a value that varies depending on these conditions. Furthermore, when the discharge amount Q2p is affected by the printing duty, the discharge amount Q2p may be a value that varies depending on the printing duty.

[0079] The total discharge amount Q2 may be calculated by adding up the amount of liquid sucked from the liquid ejection head 13a by the suction cleaning. For example, the total discharge amount Q2 may be calculated by adding up the value obtained by multiplying the suction amount Q2s in one suction cleaning by the number of suction cleanings ns. That is, the control unit 100 may calculate the total discharge amount Q2 by the formula Q2=(Q2p×np)+(Q2s×ns).

[0080] The suction amount Q2s in the first liquid container 14f is the amount of liquid in the first liquid container 14f that is sucked from the entire liquid ejection head 13a in one suction cleaning when the first liquid container 14f is pressurized. The number of suction cleanings ns is the number of times that suction cleaning has been performed on the liquid ejection head 13a since the liquid container 14 was attached to the liquid ejection device 11. When the strength at which the liquid is sucked is adjusted in the suction cleaning, the suction amount Q2s may be a value that varies depending on the strength at which the liquid is sucked.

[0081] The total discharge amount Q2 may be calculated by adding up the amount of liquid that leaks from the nozzles 12 of the liquid ejection head 13a and is wiped away by the pressurized wiping. For example, the total discharge amount Q2 may be calculated by adding up the value obtained by multiplying the leakage amount Q2w in one pressurized wiping by the number of pressurized wipings nw. That is, the control unit 100 may calculate the total discharge amount Q2 by the formula Q2=(Q2p×np)+(Q2s×ns)+(Q2w×nw).

[0082] The leakage amount Q2w in the first liquid container 14f is the amount of liquid in the first liquid container 14f that leaks from the entire liquid ejection head 13a during one pressurized wiping when the first liquid container 14f is pressurized. The number of pressurized wipings nw is the number of times pressurized wiping has been performed on the liquid ejection head 13a since the liquid container 14 was attached to the liquid ejection device 11. When the strength at which the liquid leaks during pressurized wiping is adjusted, the leakage amount Q2w may be a value that varies depending on the strength at which the liquid leaks.

[0083] The control unit 100 calculates the remaining amount Q3 by subtracting the total discharge amount Q2 from the storage amount Q1. That is, the control unit 100 calculates the remaining amount Q3 using the formula Q3=Q1-Q2. The control unit 100 then calculates the remaining amount Q3 for each liquid container 14. This allows the control unit 100 to detect that the remaining amount of liquid in the liquid container 14 has fallen below the first threshold value QL1 without referring to the detection result of the detection unit 31. In other words, the control unit 100 can detect that the remaining amount of liquid in the liquid container 14 has fallen below the first threshold value QL1 from both the detection result of the detection unit 31 and the calculation result of the remaining amount Q3.

[0084] <Configuration of the suction mechanism> 6, the suction mechanism 84 includes a discharge flow path 85, a pressure chamber 111, and a discharge valve 112. The pressure chamber 111 is disposed in the discharge flow path 85, and is located downstream of the suction valve 86. The discharge valve 112 is disposed in the discharge flow path 85, downstream of the pressure chamber 111. The discharge valve 112 is configured to open and close the discharge flow path 85.

[0085] When the waste liquid in the cap 83 is discharged through the discharge flow path 85, it is temporarily stored in the pressure chamber 111. The suction mechanism 84 may include a pressure sensor 113 and a release valve 114 connected to the pressure chamber 111. The pressure sensor 113 detects the pressure in the pressure chamber 111. When the release valve 114 opens, the inside of the pressure chamber 111 communicates with the atmosphere. The discharge valve 112 may be a one-way valve that allows the flow of liquid from upstream to downstream and restricts the flow of liquid from downstream to upstream. More specifically, the discharge valve 112 opens the discharge flow path 85 when a certain pressure or more is applied from upstream without being electrically or mechanically controlled, but autonomously closes the discharge flow path 85 under normal conditions (atmospheric pressure) and when pressure is applied from downstream.

[0086] The suction mechanism 84 may include a waste liquid tank 115 connected downstream of the discharge valve 112 of the discharge flow path 85. When the inside of the pressure chamber 111 is pressurized, the waste liquid in the pressure chamber 111 flows into the waste liquid tank 115 through the discharge flow path 85. At this time, the discharge valve 112, which is a one-way valve, is opened by the pressure of the pressurized waste liquid. If the discharge valve 112 opens and closes under control, it is preferable to open the discharge valve 112 when pressurizing the inside of the pressure chamber 111. The waste liquid tank 115 may be attached to the liquid discharge device 11 in a replaceable manner.

[0087] The suction mechanism 84 includes a cleaning pump 116, a pressure reduction flow path 117, and a pressure reduction valve 118. The cleaning pump 116 is configured to reduce the pressure inside the pressure chamber 111 until it becomes negative pressure. The cleaning pump 116 is connected to the pressure chamber 111 via the pressure reduction flow path 117. The pressure reduction valve 118 is disposed midway along the pressure reduction flow path 117, between the pressure chamber 111 and the cleaning pump 116.

[0088] The pressure reducing valve 118 is configured to open and close the pressure reducing passage 117. When the pressure reducing valve 118 is open, the cleaning pump 116 communicates with the pressure chamber 111, and when the pressure reducing valve 118 is closed, the suction force of the cleaning pump 116 does not affect the pressure chamber 111.

[0089] The suction mechanism 84 includes a pressurized flow passage 127 that communicates with the supply pump 44 and the pressure chamber 111, and a pressurized valve 128 that is configured to open and close the pressurized flow passage 127. The pressurized flow passage 127 may be a flow passage branched off from the delivery flow passage 47.

[0090] When the pressurizing valve 128 is opened, the supply pump 44 communicates with the pressure chamber 111, and when the pressurizing valve 128 is closed, the pressurizing force of the supply pump 44 is not applied to the pressure chamber 111. The supply pump 44 can pressurize the inside of the pressure chamber 111 through the pressurizing flow path 127. When liquid is supplied to the liquid ejection head 13a (when ejecting liquid and when performing pressurized cleaning), the pressurizing valve 128 closes the pressurizing flow path 127.

[0091] <Electrical Configuration of the Liquid Discharger 11> As shown in Fig. 7, the liquid ejection device 11 has a control unit 100. The control unit 100 includes a CPU 142 and a storage unit 143. The CPU 142 is a central processing unit that performs overall control of the liquid ejection device 11. The storage unit 143 is a non-volatile memory that stores programs executed by the CPU 142, including various maintenance operations, and related information thereof. In addition to the pressure sensor 113, an operation unit 105 and an ejection failure detection unit 146 are connected to an input side interface (not shown) of the control unit 100.

[0092] The pressure sensor 113 periodically detects the pressure inside the pressure chamber 111, and transmits a detection signal indicating the detection result to the control unit 100. The ejection failure detection unit 146 is, for example, a detection circuit that detects residual vibration of the cavity inside the liquid ejection unit 13. That is, a nozzle 12 having an ejection failure is detected by using the piezoelectric element to detect the residual vibration after the inside of the cavity is vibrated by driving the piezoelectric element.

[0093] For example, when the viscosity of the liquid in the cavity increases, the residual vibration is more likely to attenuate, and the period of the residual vibration becomes shorter. On the other hand, when air bubbles are mixed in the cavity, the residual vibration is less likely to attenuate, and the period of the residual vibration becomes longer. When the period of the residual vibration in the cavity detected by the piezoelectric element becomes shorter than a predetermined lower limit period or longer than a predetermined upper limit period, the discharge failure detection unit 146 detects the nozzle 12 corresponding to the cavity and the piezoelectric element as a nozzle 12 with a discharge failure. Furthermore, the discharge failure detection unit 146 transmits a detection signal indicating the detection result to the control unit 100. The control unit 100 may execute a maintenance operation such as suction cleaning or pressure cleaning based on the detection result of the discharge failure detection unit 146.

[0094] As shown in Fig. 7, a plurality of types of drive circuits are connected to an output side interface (not shown) of the control unit 100. The piezoelectric element drive circuit 147 drives a piezoelectric element to eject liquid from the nozzle 12 corresponding to that piezoelectric element. The piezoelectric element drive circuit 147 also drives the piezoelectric element when detecting residual vibration to detect a nozzle 12 with an ejection defect. The cap drive circuit 148 drives a lifting mechanism that lifts and lowers the cap 83. The cleaning pump drive circuit 149 drives the cleaning pump 116.

[0095] The supply pump drive circuit 150 drives the supply pump 44. The suction valve drive circuit 151 drives the suction valve 86 to open or close. The pressurizing valve drive circuit 152 drives the pressurizing valve 128 to open or close. The decompression valve drive circuit 153 drives the decompression valve 118 to open or close. The release valve drive circuit 154 drives the release valve 114 to open or close. The discharge valve drive circuit 155 drives the discharge valve 112 to open or close. Each of the above drive circuits drives a corresponding drive target based on a control signal appropriately transmitted from the control unit 100. If the discharge valve 112 is a one-way valve that opens and closes autonomously, the liquid discharger 11 does not need to include the discharge valve drive circuit 155. That is, in the following description, when it is stated that "the control unit 100 opens (or closes) the exhaust valve 112", the exhaust valve 112 opens (or closes) autonomously without being controlled.

[0096] The operation of the first embodiment will be described. When the liquid ejection device 11 performs recording on the medium M, the first delivery valve 29f and the first valve 24f are opened, and the supply pump 44 is driven. By driving the supply pump 44, gas flows into the storage container 21 that contains the first liquid container 14f, pressurizing the inside of the storage container 21. When the inside of the storage container 21 is pressurized, the first liquid container 14f is compressed, and the liquid in the first liquid container 14f is delivered to the liquid ejection head 13a. At this time, the second delivery valve 29s and the second valve 24s are closed.

[0097] The liquid delivered from the liquid container 14 is temporarily stored in the storage section 25 via the first supply flow path 91. When the pressure of the liquid in the first supply flow path 91 decreases, the movable wall 32 is displaced toward the inside of the storage section 25, which in turn displaces the movable body 33 and the lever 35. The detection section 31 detects the displacement of the lever 35, thereby detecting the remaining amount of liquid in the liquid container 14.

[0098] The pressure of the liquid temporarily stored in the storage unit 25 is adjusted by the pressure adjustment unit 50, and the liquid is supplied to the liquid ejection head 13a through the supply restriction unit 60 and the liquid pressurization unit 70. The liquid supplied to the liquid ejection head 13a is ejected from the multiple nozzles 12 onto the medium M.

[0099] The liquid ejection device 11 performs various maintenance operations. In order to discharge thickened liquid, air bubbles, and foreign matter that may cause ejection defects from the nozzles 12, flushing is performed in which the liquid ejection head 13a ejects droplets from the nozzles 12 toward the inside of the cap 83. In addition, in order to suppress thickening of the liquid inside the nozzles 12, capping is performed in which the cap 83 abuts against the liquid ejection head 13a so as to surround the opening of the nozzle 12 when the liquid ejection head 13a is not ejecting liquid.

[0100] Furthermore, the liquid ejection device 11 executes suction cleaning. First, the control unit 100 moves the cap 83 corresponding to the liquid ejection head 13a that requires suction cleaning to the capping position. Then, the control unit 100 opens the decompression valve 118, and drives the cleaning pump 116 with the suction valve 86, the release valve 114, the exhaust valve 112, and the pressurization valve 128 closed. This causes the gas in the pressure chamber 111 to be exhausted through the decompression flow path 117, and the pressure in the pressure chamber 111 is reduced to a negative pressure.

[0101] Thereafter, when the control unit 100 closes the pressure reducing valve 118 and opens the suction valve 86, the negative pressure accumulated in the pressure chamber 111 acts on the closed space CS. The nozzle 12 that opens into the closed space CS communicates with the third supply flow path 93 via the fifth supply flow path 95, the liquid chamber 72 of the liquid pressurizing unit 70, the fourth supply flow path 94, and the liquid chamber 62 of the supply regulating unit 60. As a result, the pressure of the third supply flow path 93 becomes less than the predetermined pressure, and the pressure adjusting unit 50 communicates the second supply flow path 92 with the third supply flow path 93. Therefore, the liquid is continuously supplied from the liquid storage unit 20 to the liquid ejection unit 13, and the liquid is discharged from the nozzle 12 through the discharge flow path 85.

[0102] When the exhaust valve 112 is a one-way valve, the exhaust valve 112 is not opened or closed by the control unit 100, and allows the liquid to flow from the upstream to the downstream of the exhaust flow path 85. After the suction cleaning is performed, the release valve 114 may be opened once to open the inside of the pressure chamber 111 to the atmosphere.

[0103] Furthermore, the liquid discharger 11 performs pressure cleaning, for example, after suction cleaning. In detail, after suction cleaning is performed, the control unit 100 moves the cap 83 to the open position. Then, the control unit 100 closes the pressure valve 128 and the first open valve 66, and drives the supply pump 44 with the third delivery valve 45 open. As a result, gas flows into the gas chamber 61 of the supply restriction unit 60 via the second delivery passage 42, and the gas chamber 61 is pressurized.

[0104] When the pressure in the gas chamber 61 becomes greater than the pressure in the liquid chamber 62, the film member 64 reduces the volume of the liquid chamber 62 against the biasing force of the biasing member 65. Then, the film member 64 closes the opening 67 of the protruding portion 63 of the liquid chamber 62. This restricts the supply of liquid from the liquid storage portion 20 to the liquid discharge portion 13.

[0105] The control unit 100 closes the second release valve 75 and drives the supply pump 44 with the fourth delivery valve 46 open. As a result, gas flows into the gas chamber 71 of the liquid pressurizing unit 70 via the third delivery flow path 43, and the gas chamber 71 is pressurized. When the pressure in the gas chamber 71 becomes greater than the pressure in the liquid chamber 72, the film member 73 reduces the volume of the liquid chamber 72 against the biasing force of the biasing member 74. As a result, the liquid inside the liquid ejection head 13a and inside the nozzle 12 is pressurized.

[0106] When the liquid pressure in the nozzles 12 of all the liquid ejection heads 13a becomes higher than atmospheric pressure, liquid leaks out from the nozzles 12 of all the liquid ejection heads 13a. The control unit 100 drives the movement mechanism to perform wiping by the wiper 88 of the nozzle surfaces 12a of all the liquid ejection heads 13a.

[0107] After suction cleaning or pressure cleaning, the inside of the cap 83 may be suctioned while the cap 83 is in the open position or while the inside of the cap 83 is open to the atmosphere. This is an operation for discharging the waste liquid remaining in the cap 83 through the discharge flow path 85, and is also called empty suction. When empty suction is performed, the cleaning pump 116 is driven in the same way as in suction cleaning to reduce the pressure inside the pressure chamber 111 to a negative pressure, and then the suction valve 86 is opened.

[0108] The waste liquid received in the cap 83 is temporarily stored in a pressure chamber 111 arranged in the middle of the discharge flow path 85. When the amount of waste liquid in the pressure chamber 111 reaches a certain amount or more, the control unit 100 discharges the waste liquid stored in the pressure chamber 111 to a waste liquid tank 115. More specifically, the control unit 100 opens the pressurizing valve 128 and the discharge valve 112, and drives the supply pump 44 while keeping the suction valve 86, the release valve 114, and the decompression valve 118 closed. As a result, gas flows into the pressure chamber 111 through the pressurizing flow path 127, and the pressure chamber 111 is pressurized. Then, the waste liquid in the pressure chamber 111 is discharged into the waste liquid tank 115 through the discharge flow path 85. After the pressure chamber 111 is pressurized, the release valve 114 may be opened to open the pressure chamber 111 to the atmosphere.

[0109] When pressurizing or depressurizing the inside of the pressure chamber 111, the time for pressurizing or depressurizing may be changed based on the detection result of the pressure sensor 113. This allows, for example, increasing the depressurization time to increase the negative pressure and perform more powerful suction cleaning. Also, for example, if the inside of the pressure chamber 111 is pressurized while an operation such as wiping is being performed, the waste liquid in the pressure chamber 111 can be discharged more quickly.

[0110] According to the first embodiment, the following effects can be obtained. (1-1) By pressurizing the inside of the pressure chamber 111 with the supply pump 44, the waste liquid in the pressure chamber 111 can be discharged through the discharge flow path 85. Since the liquid discharger 11 discharges the waste liquid using the supply pump 44 for supplying the liquid, it is not necessary to have a dedicated pump for discharging the waste liquid. Therefore, the configuration of the liquid discharger 11 can be simplified.

[0111] (1-2) Pressurized cleaning can be performed using the supply pump 44 for supplying liquid. The liquid ejection device 11 does not need to include a dedicated pressurized pump for performing pressurized cleaning. This allows the configuration of the liquid ejection device 11 to be simplified.

[0112] (1-3) When the cleaning pump 116 is driven with the suction valve 86, the pressurizing valve 128, and the exhaust valve 112 closed, the pressure inside the pressure chamber 111 is reduced to a negative pressure. When the suction valve 86 is then opened, the negative pressure inside the pressure chamber 111 acts on the inside of the cap 83. This allows suction cleaning to be performed, in which the liquid inside the liquid ejection head 13a is exhausted through the nozzle 12.

[0113] (1-4) When the exhaust valve 112 is a one-way valve that opens and closes autonomously, there is no need to provide a mechanism for opening and closing the exhaust valve 112. This allows the configuration of the liquid ejection device 11 to be simplified.

[0114] Second embodiment Hereinafter, a second embodiment of the liquid ejection device 11 will be described with reference to the drawings. The same components as those in the first embodiment are denoted by the same reference numerals, and duplicated descriptions will be omitted.

[0115] 8, the suction mechanism 84 includes a pressure reduction flow path 117, a pressure reduction flow path release valve 129, and a pressure reduction flow path release valve 119. The suction mechanism 84 of the second embodiment does not include the cleaning pump .

[0116] The supply pump 44 has a suction port and a discharge port. The pressure reduction flow path 117 has an upstream end communicating with the pressure chamber 111 and a downstream end communicating with the suction port of the supply pump 44. The discharge port of the supply pump 44 is connected to the upstream end of the delivery flow path 47.

[0117] The pressurized flow path release valve 129 is connected to the pressurized flow path 127 between the supply pump 44 and the pressurized valve 128. When the pressurized flow path release valve 129 is opened, the pressurized flow path 127 is communicated with the atmosphere. The reduced pressure flow path release valve 119 is connected to the reduced pressure flow path 117 between the supply pump 44 and the reduced pressure valve 118. When the reduced pressure flow path release valve 119 is opened, the reduced pressure flow path 117 is communicated with the atmosphere.

[0118] When the supply pump 44 is driven to pressurize the storage vessel 21, the gas chamber 61, the gas chamber 71, or the pressure chamber 111, the pressurized flow path release valve 129 is closed and the reduced pressure flow path release valve 119 is opened.

[0119] The operation of the second embodiment will be described with respect to the differences from the first embodiment. When suction cleaning is performed, the control unit 100 first moves the cap 83 corresponding to the liquid ejection head 13a that requires suction cleaning to the capping position. Then, the control unit 100 opens the decompression valve 118 and the pressurized flow path opening valve 129, closes the suction valve 86, the discharge valve 112, the pressurized valve 128, and the decompression flow path opening valve 119, and drives the supply pump 44. As a result, the gas in the pressure chamber 111 is discharged through the decompression flow path 117, and the pressure in the pressure chamber 111 is reduced to a negative pressure. Thereafter, the control unit 100 closes the decompression valve 118 and the pressurized flow path opening valve 129, and opens the suction valve 86. As a result, the negative pressure accumulated in the pressure chamber 111 acts on the closed space CS, and the liquid in the liquid ejection head 13a is discharged into the closed space CS through the nozzle 12.

[0120] When pressure cleaning is performed, the control unit 100 performs the same control as in the first embodiment, and applies the pressure force of the supply pump 44 to the nozzle 12. When performing dry suction, the inside of the cap 83 is suctioned with the cap 83 in the open position or with the inside of the cap 83 open to the atmosphere. More specifically, similarly to the suction cleaning, the supply pump 44 is driven to reduce the pressure inside the pressure chamber 111 to a negative pressure, and then the suction valve 86 is opened.

[0121] When the waste liquid in the pressure chamber 111 is to be discharged into the waste liquid tank 115, the control unit 100 drives the supply pump 44 to pressurize the inside of the pressure chamber 111. More specifically, the control unit 100 closes the suction valve 86, the pressurization flow path release valve 129, and the decompression valve 118, and opens the pressurization valve 128 and the decompression flow path release valve 119. When the control unit 100 drives the supply pump 44 in this state, the inside of the pressure chamber 111 is pressurized through the pressurization flow path 127. As a result, the waste liquid in the pressure chamber 111 is discharged into the waste liquid tank 115 through the discharge flow path 85.

[0122] According to the second embodiment, the following effects can be obtained. (2-1) By pressurizing the inside of the pressure chamber 111 with the supply pump 44, the waste liquid in the pressure chamber 111 can be discharged through the discharge flow path 85. Since the liquid discharger 11 discharges the waste liquid using the supply pump 44 for supplying the liquid, it is not necessary to have a dedicated pump for discharging the waste liquid. Therefore, the configuration of the liquid discharger 11 can be simplified.

[0123] (2-2) Pressurized cleaning can be performed using the supply pump 44 for supplying liquid. The liquid ejection device 11 does not need to include a dedicated pump for performing pressurized cleaning. This allows the configuration of the liquid ejection device 11 to be simplified.

[0124] (2-3) Suction cleaning can be performed using the supply pump 44 for supplying liquid. The liquid ejection device 11 does not need to include a dedicated pump for suction cleaning. This allows the configuration of the liquid ejection device 11 to be simplified.

[0125] Third embodiment Hereinafter, a third embodiment of the liquid ejection device 11 will be described with reference to the drawings. The same components as those in the first embodiment are denoted by the same reference numerals, and duplicated descriptions will be omitted.

[0126] 9, the suction mechanism 84 includes a cleaning pump 116, a decompression flow path 117, a pressurized flow path 127, a decompression flow path release valve 119, and a pressurized flow path release valve 129. The cleaning pump 116 has a suction port and a discharge port. The decompression flow path 117 has an upstream end communicating with the pressure chamber 111 and a downstream end communicating with the suction port of the cleaning pump 116. The pressurized flow path 127 has an upstream end communicating with the suction port of the cleaning pump 116 and a downstream end communicating with the pressure chamber 111. The cleaning pump 116 is configured to reduce the pressure inside the pressure chamber 111 through the decompression flow path 117.

[0127] A pressure reducing valve 118 that opens and closes the pressure reducing flow path 117 is disposed midway through the pressure reducing flow path 117. The pressure reducing valve 118 is configured to open and close the pressure reducing flow path 117. The pressure reducing flow path opening valve 119 is connected to the pressure reducing flow path 117 between the pressure reducing valve 118 and the cleaning pump 116. When the pressure reducing flow path opening valve 119 opens, the pressure reducing flow path 117 communicates with the atmosphere.

[0128] A pressurization valve 128 that opens and closes the pressurization flow path 127 is disposed in the middle of the pressurization flow path 127. A pressurization flow path release valve 129 is connected to the pressurization flow path 127 between the pressure chamber 111 and the cleaning pump 116. When the pressurization flow path release valve 129 opens, the pressurization flow path 127 communicates with the atmosphere.

[0129] When the suction valve 86, the pressurization valve 128, the exhaust valve 112, and the pressure reduction flow path release valve 119 are closed, and the pressure reduction valve 118 and the pressurization flow path release valve 129 are opened to drive the cleaning pump 116, the pressure in the pressure chamber 111 is reduced to a negative pressure. When the suction valve 86 is subsequently opened, the negative pressure in the pressure chamber 111 acts on the closed space CS defined by the cap 83. This negative pressure causes the liquid to be sucked from the nozzle 12 of the liquid ejection head 13a and discharged through the discharge flow path 85.

[0130] When the cleaning pump 116 is driven with the suction valve 86, the pressure reducing valve 118, and the pressure reducing flow path release valve 129 closed and the pressure reducing valve 128, the discharge valve 112, and the pressure reducing flow path release valve 119 open, the inside of the pressure chamber 111 is pressurized. As a result, waste liquid is discharged from the inside of the pressure chamber 111 through the discharge flow path 85.

[0131] The operation of the third embodiment will be described with reference to the differences from the first and second embodiments. When performing suction cleaning, the control unit 100 first moves the cap 83 corresponding to the liquid ejection head 13a that requires suction cleaning to a capping position. Then, the control unit 100 closes the suction valve 86, the discharge valve 112, the pressurizing valve 128, and the decompression flow path opening valve 119, and opens the pressurizing flow path opening valve 129 and the decompression valve 118 to drive the cleaning pump 116. As a result, the gas in the pressure chamber 111 is discharged through the decompression flow path 117, and the pressure in the pressure chamber 111 is reduced to a negative pressure. Thereafter, the control unit 100 closes the decompression valve 118 and the pressurizing flow path opening valve 129, and opens the suction valve 86. As a result, the negative pressure accumulated in the pressure chamber 111 acts on the closed space CS, and the liquid in the liquid ejection head 13a is discharged into the closed space CS through the nozzle 12.

[0132] When pressure cleaning is performed, the control unit 100 performs the same control as in the first embodiment, and applies the pressure force of the supply pump 44 to the nozzle 12. When performing dry suction, the inside of the cap 83 is suctioned with the cap 83 in the open position or with the inside of the cap 83 open to the atmosphere. More specifically, similarly to the suction cleaning, the cleaning pump 116 is driven to reduce the pressure inside the pressure chamber 111 to a negative pressure, and then the suction valve 86 is opened.

[0133] When the waste liquid in the pressure chamber 111 is discharged to the waste liquid tank 115, the control unit 100 drives the cleaning pump 116 to pressurize the inside of the pressure chamber 111. More specifically, the control unit 100 closes the suction valve 86, the pressurization flow path release valve 129, and the decompression valve 118, and opens the pressurization valve 128, the discharge valve 112, and the decompression flow path release valve 119. When the control unit 100 drives the cleaning pump 116 in this state, the inside of the pressure chamber 111 is pressurized through the pressurization flow path 127. As a result, the waste liquid in the pressure chamber 111 is discharged into the waste liquid tank 115 through the discharge flow path 85.

[0134] According to the third embodiment, the following effects can be obtained. (3-1) The cleaning pump 116 pressurizes the pressure chamber 111, thereby discharging the waste liquid from the pressure chamber 111 through the discharge flow path 85. The liquid discharger 11 discharges the waste liquid using the cleaning pump 116 for reducing the pressure in the pressure chamber 111, so there is no need to provide a dedicated pump for discharging the waste liquid. This allows the configuration of the liquid discharger 11 to be simplified.

[0135] (3-2) When the cleaning pump 116 is driven with the suction valve 86, the pressurizing valve 128, and the exhaust valve 112 closed, the pressure inside the pressure chamber 111 is reduced to a negative pressure. When the suction valve 86 is then opened, the negative pressure inside the pressure chamber 111 acts on the inside of the cap 83. This allows suction cleaning to be performed, in which the liquid inside the liquid ejection head 13a is exhausted through the nozzle 12.

[0136] (3-3) When the suction valve 86 is closed, the pressurization valve 128 and the discharge valve 112 are opened, and the cleaning pump 116 is driven, the inside of the pressure chamber 111 is pressurized. This makes it possible to discharge the waste liquid from the pressure chamber 111. Since the liquid discharger 11 discharges the waste liquid using the cleaning pump 116 for reducing the pressure inside the pressure chamber 111, it is not necessary to have a dedicated pump for discharging the waste liquid. This makes it possible to simplify the configuration of the liquid discharger 11.

[0137] The above-described embodiments may be modified as shown in the following modified examples. In addition, the configurations included in these embodiments may be arbitrarily combined with the configurations included in the following modified examples, or the configurations included in the following modified examples may be arbitrarily combined with each other.

[0138] The cleaning pump 116 or the supply pump 44 may be kept driven even after the suction valve 86 is opened to apply the negative pressure in the pressure chamber 111 to the closed space CS. This allows the negative pressure to be applied to the closed space CS for a longer period of time.

[0139] The pressurizing valve 128 may be a switching valve, and a pressurizing flow path branching from the switching valve may be provided. Each branched pressurizing flow path may have an outlet arranged to blow pressurized air to at least one of the nozzle surface 12a, the wiper 88 in the standby position, or the opening (cap lip) of the cap 83 in the standby position. This allows foreign matter such as liquid, dust, or paper powder adhering to the nozzle surface 12a, the wiper 88, or the cap lip to be removed by the pressurized air. Alternatively, the outlet of the branched pressurizing flow path may be arranged inside the medium storage unit 106. This allows paper powder adhering to the medium M before recording to be removed by the pressurized air.

[0140] As in the modified example shown in FIG. 10, the liquid ejection device 11 of the first embodiment may be configured to supply liquid by utilizing the head difference between the inside of the liquid container 14 and the inside of the liquid ejection head 13a. A liquid ejection device 11 according to this modified example includes a liquid ejection head 13a, a supply mechanism 40 that supplies the liquid contained in a liquid container 14 to the liquid ejection head 13a, and a drive mechanism 130 that drives the supply mechanism 40.

[0141] The supply mechanism 40 includes a first storage container 131, a communication passage 334, and a second storage container 134. The communication passage 334 has an upstream end connected to the first storage container 131 and a downstream end connected to the second storage container 134. The first storage container 131 and the second storage container 134 store the liquid supplied from the liquid container 14.

[0142] The supply mechanism 40 includes a first valve 336 capable of closing the communication passage 334, and a supply flow path 337 that supplies liquid from the second storage container 134 to the liquid ejection head 13a. The supply mechanism 40 may also include a second valve 338, a recovery flow path 339 for recovering liquid from the liquid ejection head 13a to the first storage container 131, a third valve 340 capable of opening and closing the recovery flow path 339, and a liquid chamber 341 disposed midway along the recovery flow path 339. The second valve 338 is capable of closing the supply flow path 337 between the second storage container 134 and the liquid ejection head 13a.

[0143] The liquid chamber 341 is disposed between the liquid ejection head 13a and the third valve 340. A portion of the liquid chamber 341 is defined by a flexible member 342. The volume of the liquid chamber 341 changes as the flexible member 342 deforms.

[0144] The liquid ejection head 13a may have a first connection portion 344 and a second connection portion 345. The recovery flow path 339 has an upstream end connected to the first connection portion 344 and a downstream end connected to the first storage container 131. The supply flow path 337 has an upstream end connected to the second storage container 134 and a downstream end connected to the second connection portion 345.

[0145] The drive mechanism 130 includes a supply pump 44 that pressurizes the second storage container 134. In other words, the supply pump 44 is configured to pressurize the inside of a supply flow path for supplying the liquid in the liquid container 14 to the liquid ejection head 13a. The drive mechanism 130 may include a switching mechanism 348 connected to the supply pump 44, and a pressure sensor 349 that detects the pressure. The drive mechanism 130 may include an atmosphere open path 350 connected to the first storage container 131, a pressurized flow path 351 connected to the second storage container 134, and a connection flow path 352 that connects the atmosphere open path 350 and the pressurized flow path 351 to the supply pump 44. The drive mechanism 130 may include an air chamber 353 separated from the liquid chamber 341 via a flexible member 342, a spring 354 provided in the air chamber 353, and an air flow path 355 connected to the air chamber 353. The spring 354 presses the flexible member 342, thereby reducing pressure fluctuations of the liquid in the recovery passageway 339 and the liquid ejection head 13a.

[0146] Supply pump 44 has a suction port and a discharge port. Air flow path 355 is connected to the suction port, and connection flow path 352 is connected to the discharge port. Supply pump 44, when driven in the forward direction, sends out air taken in from air flow path 355 to connection flow path 352. Supply pump 44, when driven in the reverse direction, sends out air taken in from connection flow path 352 to air flow path 355.

[0147] The pressurizing mechanism 357 includes the supply pump 44, an air chamber 353, an air flow path 355 that connects the supply pump 44 to the air chamber 353, and a pressurizing flow path 127 that connects the supply pump 44 to the pressure chamber 111. The slight pressurizing unit 358 includes the pressurizing mechanism 357 and a liquid chamber 341. The slight pressurizing unit 358 has the liquid chamber 341 and the pressurizing mechanism 357 that can pressurize the flexible member 342 from outside the liquid chamber 341. The slight pressurizing unit 358 is disposed in the recovery flow path 339 between the liquid ejection head 13a and the third valve 340. The slight pressurizing unit 358 is configured to pressurize the liquid in the recovery flow path 339.

[0148] The liquid container 14 has a storage chamber 329 that stores liquid. The first storage container 131 has an introduction part 360 that can introduce the liquid stored in the liquid container 14 attached to the attachment part 328. The first storage container 131 may have an apparatus side valve 361 provided in the introduction part 360, a first storage chamber 362 that stores liquid, a liquid amount sensor 363 that detects the amount of liquid stored in the first storage chamber 362, and a first gas-liquid separation membrane 364 that separates the first storage chamber 362 from the atmosphere open path 350. The first gas-liquid separation membrane 364 is a membrane that has the property of passing gas but not passing liquid.

[0149] The valves 331 and 361 open when the liquid container 14 is attached to the attachment portion 328 , and maintain the open state while the liquid container 14 is attached to the attachment portion 328 . The introduction part 360 is disposed at the upper part of the first storage container 131. The introduction part 360 of this modified example penetrates a ceiling 365 of the first storage chamber 362. The lower end of the introduction part 360 is located inside the first storage chamber 362 and below the ceiling 365. The upper end of the introduction part 360 is located outside the first storage chamber 362 and above the ceiling 365. The introduction part 360 is connected to the outlet part 330 of the liquid storage body 14 by mounting the liquid storage body 14 to the mounting part 328.

[0150] The second storage container 134 may have a second storage chamber 368 that stores a liquid, and a second gas-liquid separation membrane 369 that separates the second storage chamber 368 from the pressurized flow path 351. Similar to the first gas-liquid separation membrane 364, the second gas-liquid separation membrane 369 is a membrane that has the property of allowing gas to pass through but not allowing liquid to pass through.

[0151] The first valve 336 closes the communication passage 334 when the pressure in the second storage container 134 is greater than the pressure in the first storage container 131. Therefore, the first valve 336 closes the communication passage 334 when the second storage container 134 is pressurized by the supply pump 44. The first valve 336 may have a check valve that allows the flow of liquid from the first storage container 131 to the second storage container 134 and restricts the flow of liquid from the second storage container 134 to the first storage container 131.

[0152] The control unit 100 controls the opening and closing of a second valve 338 and a third valve 340. The second valve 338 can open and close the supply passage 337 when pressurized by the supply pump 44. The third valve 340 can open and close the recovery passage 339.

[0153] The switching mechanism 348 includes a thin tube section 372 provided in the connection flow path 352, first selection valves 373a to eleventh selection valves 373k that can open and close the flow path, and a pressurizing valve 128. The pressurizing valve 128 opens and closes the pressurized flow path 127. The thin tube section 372 is a meandering tube that is thin enough that the flow of liquid is significantly restricted relative to the flow of air.

[0154] When the first selection valve 373a is opened, the inside of the air flow path 355 is connected to the atmosphere. When the second selection valve 373b is opened, the air flow path 355 is connected to the pressure sensor 349. When the third selection valve 373c is opened, the air flow path 355 is opened and the supply pump 44 is connected to the air chamber 353. When the pressurization valve 128 is opened, the pressurization flow path 127 is opened and the supply pump 44 is connected to the pressure chamber 111.

[0155] When the fourth selection valve 373d is opened, the connection flow path 352 between the supply pump 44 and the eighth selection valve 373h is connected to the atmosphere. When the fifth selection valve 373e is opened, the connection flow path 352 is connected to the pressure sensor 349. When the sixth selection valve 373f and the seventh selection valve 373g are opened, the connection flow path 352 is connected to the atmosphere. When the eighth selection valve 373h is opened, the connection flow path 352 is opened. When the ninth selection valve 373i is opened, the thin tube portion 372 is connected to the atmosphere. When the tenth selection valve 373j is opened, the atmosphere release path 350 is opened, and the first storage container 131 is connected to the connection flow path 352. When the eleventh selection valve 373k is opened, the pressurized flow path 351 is opened, and the second storage container 134 is connected to the connection flow path 352.

[0156] The liquid in the liquid container 14 flows into the first storage container 131 through the outlet portion 330 and the inlet portion 360 due to the hydraulic head difference. The liquid in the first storage container 131 flows into the second storage container 134 due to the hydraulic head difference.

[0157] The lower end of the introduction portion 360 is located below the nozzle surface 12a. As a result, a first liquid level 366 of the liquid stored in the first storage container 131 fluctuates in a range lower than the nozzle surface 12a. When the first storage chamber 362 and the second storage chamber 368 are at atmospheric pressure, a second liquid level 370 of the liquid in the second storage chamber 368 is at the same height as the first liquid level 366. In other words, the second liquid level 370 is maintained at a standard position that is approximately the same height as the lower end of the introduction portion 360, and fluctuates in a range lower than the nozzle surface 12a.

[0158] The liquid in the liquid ejection head 13a is maintained at a negative pressure by the head difference between the liquid in the first storage container 131 and the liquid in the second storage container 134. When the liquid is consumed in the liquid ejection head 13a, the liquid stored in the second storage container 134 is supplied to the liquid ejection head 13a.

[0159] In this modification, when various cleaning operations are performed, the control unit 100 controls the pressurizing valve 128 in the same manner as in the first embodiment. When discharging waste liquid from the pressure chamber 111, the pressure chamber 111 may be pressurized by opening the pressure valve 128 and driving the supply pump 44.

[0160] The supply mechanism 40 does not necessarily have to include a mechanism for selectively pressurizing the multiple liquid containers 14f, 14s. The liquid ejection device 11 is not limited to one having a line head whose recording range spans the entire width of the medium M, but may be a serial type in which a carriage holding the liquid ejection head 13a moves in the width direction of the medium M while ejecting liquid, and transporting the medium in a transport direction intersecting the width direction of the medium M. In this case, a wiper support portion 89 may be fixed, and the nozzle surface 12a of the liquid ejection head 13a may be wiped by a wiper 88 as the carriage holding the liquid ejection head 13a moves.

[0161] The control unit 100 is not limited to a unit that includes a CPU 142 and a storage unit 143 and executes software processing. For example, the control unit 100 may include a dedicated hardware circuit (such as an ASIC) that processes at least a part of the software processing executed in the above embodiment. That is, the control unit 100 may have any one of the following configurations (a) to (c).

[0162] (a) The apparatus includes a processing device that executes all of the above processes in accordance with a program, and a program storage device such as a ROM that stores the program. (b) A processing device and a program storage device for executing part of the above processing in accordance with a program, and a dedicated hardware circuit for executing the remaining processing.

[0163] (c) Equipped with dedicated hardware circuitry for executing all of the above processes. Here, there may be a plurality of software processing circuits including a processing device and a program storage device, and a plurality of dedicated hardware circuits, that is, the above processing may be executed by a processing circuitry including at least one of one or more software processing circuits and one or more dedicated hardware circuits.

[0164] The liquid ejection device 11 may be a liquid ejection device 11 that ejects liquid other than ink. The state of the liquid ejected from the liquid ejection device 11 as minute droplets includes granular, teardrop, and thread-like tails. The liquid here may be any material that can be ejected from the liquid ejection device 11. For example, the liquid may be any state in which the substance is in a liquid phase, and includes fluids such as high or low viscosity liquids, sols, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals, and metal melts. The liquid includes not only liquids as one state of matter, but also particles of functional materials made of solids such as pigments and metal particles dissolved, dispersed, or mixed in a solvent. Representative examples of liquids include inks and liquid crystals as described in the above embodiment. Here, the ink includes various liquid compositions such as general water-based inks and oil-based inks, as well as gel inks and hot melt inks. Specific examples of the liquid ejection device 11 include a device that ejects a liquid containing materials such as electrode materials and color materials in a dispersed or dissolved form, which are used in the manufacture of liquid crystal displays, electroluminescence displays, surface-emitting displays, and color filters. The liquid ejection device 11 may be a device that ejects biological organic matter used in the manufacture of biochips, a device that ejects liquid as a sample used as a precision pipette, a textile printing device, a microdispenser, or the like. The liquid ejection device 11 may be a device that ejects lubricating oil at a pinpoint onto precision machinery such as watches and cameras, or a device that ejects transparent resin liquid such as ultraviolet curing resin onto a substrate to form a micro hemispherical lens, optical lens, or the like used in optical communication elements. The liquid ejection device 11 may be a device that ejects an etching liquid such as an acid or alkali to etch a substrate or the like.

[0165] The technical ideas and effects obtained from the above-described embodiment and modified examples will be described below. a control unit configured to control the supply pump, the cleaning pump, the suction valve, and the pressurization valve, and the pressure chamber disposed in the discharge flow path, the pressure chamber being disposed downstream of the suction valve; a control unit configured to control the supply pump, the cleaning pump, the suction valve, and the pressurization valve, and the pressure chamber disposed in the discharge flow path, the pressure chamber being disposed downstream of the suction valve;

[0166] According to this liquid ejection device, the supply pump pressurizes the pressure chamber, thereby discharging waste liquid from the pressure chamber through the discharge flow path. Since the liquid ejection device discharges waste liquid using the supply pump for supplying liquid, there is no need to have a dedicated pump for discharging waste liquid. This simplifies the configuration of the liquid ejection device.

[0167] (B) A liquid ejection device includes a liquid ejection head having a nozzle capable of ejecting liquid, a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head, a supply pump configured to pressurize the liquid in the liquid container or in the supply flow path, a cap configured to define a closed space into which the nozzle opens, a discharge flow path for discharging waste liquid, which is the liquid received in the cap, from the cap, a suction valve arranged midway through the discharge flow path, the suction valve configured to open and close the discharge flow path, and a pressure chamber arranged midway through the discharge flow path, the suction valve configured to open and close the discharge flow path, the supply pump is configured to pressurize the pressure chamber through the pressurized flow path; a pressurization valve configured to open and close the pressurized flow path; a pressure reduction flow path connecting the supply pump and the pressure chamber; a pressure reduction valve configured to open and close the pressure reduction flow path; a discharge valve disposed midway through the discharge flow path, the discharge valve configured to open and close the discharge flow path downstream of the pressure chamber; and a control unit configured to control the supply pump, the suction valve, the pressurization valve, and the pressure reduction valve, and the supply pump is configured to pressurize the pressure chamber through the pressurized flow path.

[0168] According to this liquid ejection device, the supply pump pressurizes the pressure chamber, thereby discharging waste liquid from the pressure chamber through the discharge flow path. Since the liquid ejection device discharges waste liquid using the supply pump for supplying liquid, there is no need to have a dedicated pump for discharging waste liquid. This simplifies the configuration of the liquid ejection device.

[0169] (C) In the liquid ejection device described above, the control unit may be configured to drive the supply pump to pressurize an inside of the supply flow path in order to perform pressurized cleaning to discharge the liquid from the nozzle.

[0170] According to this liquid ejection device, pressure cleaning can be performed using a supply pump for supplying liquid. The liquid ejection device does not need to have a dedicated pressure pump for performing pressure cleaning. This simplifies the configuration of the liquid ejection device.

[0171] (D) A liquid ejection device includes a liquid ejection head having a nozzle capable of ejecting liquid, a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head, a cap configured to define a closed space into which the nozzle opens, a discharge flow path for discharging waste liquid, which is the liquid received in the cap, from the cap, a suction valve configured to open and close the discharge flow path, a pressure chamber arranged in the middle of the discharge flow path, the pressure chamber arranged downstream of the suction valve, a cleaning pump configured to reduce the pressure inside the pressure chamber, a pressurized flow path communicating with the cleaning pump and the pressure chamber, a pressurized valve configured to open and close the pressurized flow path, a discharge valve arranged in the middle of the discharge flow path, the discharge valve configured to open and close the discharge flow path downstream of the pressure chamber, and a control unit configured to control the cleaning pump, the suction valve, and the pressurized valve, and the cleaning pump is configured to pressurize the pressure chamber through the pressurized flow path.

[0172] According to this liquid ejection device, the cleaning pump pressurizes the pressure chamber, thereby discharging waste liquid from the pressure chamber through the discharge flow path. Since the liquid ejection device uses the cleaning pump to reduce the pressure in the pressure chamber to discharge the waste liquid, there is no need to have a dedicated pump for discharging the waste liquid. This simplifies the configuration of the liquid ejection device.

[0173] (E) In the above liquid ejection device, the control unit may be configured to reduce the pressure in the pressure chamber to a negative pressure by driving the cleaning pump with the suction valve, the pressurization valve, and the exhaust valve closing the exhaust flow path, and then to open the suction valve to apply the negative pressure in the pressure chamber to the closed space defined by the cap.

[0174] According to this liquid ejection device, the pressure inside the pressure chamber can be reduced to a negative pressure by driving the cleaning pump. Then, the suction valve is opened to apply the negative pressure inside the pressure chamber to the inside of the cap, thereby performing suction cleaning to discharge the liquid inside the liquid ejection head through the nozzle.

[0175] (F) The liquid ejection device may include a pressurized flow path open valve disposed between the supply pump and the pressurized valve, and the control unit may be configured to, with the suction valve, the pressurized valve, and the exhaust valve closing the exhaust flow path, open the pressure reduction valve and the pressurized flow path open valve to drive the supply pump to reduce the pressure inside the pressure chamber to a negative pressure, and then open the suction valve to apply the negative pressure inside the pressure chamber to the closed space defined by the cap.

[0176] According to this liquid ejection device, the pressure inside the pressure chamber can be reduced to a negative pressure by driving the supply pump, and the negative pressure thus generated can be applied to the inside of the cap, thereby performing suction cleaning to discharge the liquid inside the liquid ejection head through the nozzle.

[0177] (G) In the above liquid ejection device, the control unit may be configured to discharge the waste liquid from the pressure chamber by driving the supply pump to pressurize the pressure chamber while the suction valve is closed and the pressurization valve and the exhaust valve are open.

[0178] According to this liquid ejection device, the inside of the pressure chamber can be pressurized by driving the supply pump, and waste liquid within the pressure chamber can be discharged. (H) In the above liquid ejection device, the control unit may be configured to discharge the waste liquid from the pressure chamber by driving the cleaning pump to pressurize the pressure chamber while the suction valve is closed and the pressurization valve and the exhaust valve are open.

[0179] According to this liquid ejection device, the inside of the pressure chamber can be pressurized by driving the cleaning pump, and waste liquid within the pressure chamber can be discharged. (I) In the above liquid ejection device, the discharge valve may be a one-way valve that allows the flow of liquid from upstream to downstream and restricts the flow of liquid from downstream to upstream.

[0180] According to this liquid ejection device, there is no need to provide a mechanism for opening and closing the discharge valve, which allows the configuration of the liquid ejection device to be simplified. (J) In a control method for a liquid ejection device, the liquid ejection device includes a liquid ejection head having a nozzle capable of ejecting liquid, a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head, a supply pump configured to pressurize the liquid in the liquid container or in the supply flow path, a cap configured to define a closed space into which the nozzle opens, a discharge flow path for discharging waste liquid, which is the liquid received in the cap, from the cap, a suction valve arranged in the middle of the discharge flow path, the suction valve configured to open and close the discharge flow path, a pressure chamber arranged in the middle of the discharge flow path, the pressure chamber arranged downstream of the suction valve, a cleaning pump configured to reduce the pressure inside the pressure chamber, a pressurization flow path communicating with the supply pump and the pressure chamber, a pressurization valve configured to open and close the pressurization flow path, and a discharge valve arranged in the middle of the discharge flow path, the discharge valve configured to open and close the discharge flow path downstream of the pressure chamber, and the supply pump is configured to pressurize the pressure chamber through the pressurization flow path. The method includes opening the pressurization valve, and discharging the waste liquid from the pressure chamber by driving the supply pump while the pressurization valve is open to pressurize the pressure chamber through the pressurization flow path.

[0181] According to this method for controlling a liquid ejection device, the supply pump pressurizes the pressure chamber, thereby discharging waste liquid from the pressure chamber through the discharge flow path. The liquid ejection device does not need to have a dedicated pump for discharging waste liquid. This simplifies the configuration of the liquid ejection device.

[0182] (K) A method for controlling a liquid ejection device, the liquid ejection device comprising: a liquid ejection head having a nozzle capable of ejecting liquid; a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head; a supply pump configured to pressurize the liquid in the liquid container or in the supply flow path; a cap configured to define a closed space into which the nozzle opens; a discharge flow path for discharging waste liquid, which is the liquid received in the cap, from the cap; a suction valve arranged in the middle of the discharge flow path, the suction valve configured to open and close the discharge flow path; a pressure chamber arranged in the middle of the discharge flow path, the pressure chamber arranged downstream of the suction valve; a pressurized flow path communicating with the supply pump and the pressure chamber, a pressurized valve configured to open and close the pressurized flow path; a reduced pressure flow path communicating with the supply pump and the pressure chamber, a reduced pressure valve configured to open and close the reduced pressure flow path; and a discharge valve arranged in the middle of the discharge flow path, the discharge valve configured to open and close the discharge flow path downstream of the pressure chamber. The method includes opening the pressurization valve, and discharging the waste liquid from the pressure chamber by driving the supply pump while the pressurization valve is open to pressurize the pressure chamber through the pressurization flow path.

[0183] According to this method for controlling a liquid ejection device, the supply pump pressurizes the pressure chamber, thereby discharging waste liquid from the pressure chamber through the discharge flow path. The liquid ejection device does not need to have a dedicated pump for discharging waste liquid. This simplifies the configuration of the liquid ejection device.

[0184] (L) The control method for the liquid ejection device includes closing the pressurization valve, and actuating the supply pump to pressurize the inside of the supply flow path and perform cleaning to discharge the liquid from the nozzle.

[0185] According to this method for controlling a liquid ejection device, pressure cleaning can be performed using a supply pump for supplying liquid. The liquid ejection device does not need to be provided with a dedicated pressure pump for performing pressure cleaning. This simplifies the configuration of the liquid ejection device.

[0186] (M) A method for controlling a liquid ejection device, the liquid ejection device comprising: a liquid ejection head having a nozzle capable of ejecting liquid; a supply flow path for flowing liquid in a liquid container toward the liquid ejection head; a cap configured to define a closed space in which the nozzle opens; a discharge flow path for discharging waste liquid, which is the liquid received in the cap, from the cap; a suction valve configured to open and close the discharge flow path; a pressure chamber disposed in the discharge flow path downstream of the suction valve; a cleaning pump configured to reduce the pressure inside the pressure chamber; a pressurized flow path communicating with the cleaning pump and the pressure chamber; a pressurized valve configured to open and close the pressurized flow path; and a discharge valve disposed in the discharge flow path downstream of the pressure chamber, the method including: opening the pressurized valve; and discharging the waste liquid from the pressure chamber by driving the cleaning pump with the pressurized valve open to pressurize the pressure chamber through the pressurized flow path.

[0187] According to this method for controlling a liquid ejection device, the cleaning pump pressurizes the pressure chamber, thereby discharging waste liquid from the pressure chamber through the discharge flow path. Since the liquid ejection device discharges waste liquid using the cleaning pump for depressurizing the pressure chamber, there is no need to have a dedicated pump for discharging waste liquid. This simplifies the configuration of the liquid ejection device.

[0188] (N) The control method of the above-mentioned liquid ejection device may include driving the cleaning pump with the suction valve and the exhaust valve closing the exhaust flow path to reduce the pressure inside the pressure chamber until a negative pressure is reached, and after the pressure inside the pressure chamber is reduced, opening the suction valve to apply the negative pressure inside the pressure chamber to the closed space.

[0189] According to this method for controlling a liquid ejection device, the pressure inside the pressure chamber can be reduced to a negative pressure by driving the cleaning pump. Then, the suction valve is opened to apply the negative pressure inside the pressure chamber to the inside of the cap, thereby performing suction cleaning to discharge the liquid inside the liquid ejection head through the nozzle.

[0190] (O) In the above-mentioned method for controlling the liquid ejection device, the liquid ejection device may further include a pressurized flow path open valve disposed between the supply pump and the pressurized valve, and the method may include driving the supply pump while the suction valve, the pressurized valve, and the exhaust valve are closed and while the pressure reduction valve and the pressurized flow path open valve are open, to reduce the pressure inside the pressure chamber until a negative pressure is reached, and after the pressure inside the pressure chamber is reduced, opening the suction valve to apply the negative pressure inside the pressure chamber to the closed space defined by the cap.

[0191] According to this method for controlling a liquid ejection device, the pressure inside the pressure chamber can be reduced to a negative pressure by driving the supply pump, and the negative pressure thus generated can be applied to the inside of the cap to perform suction cleaning, which discharges the liquid inside the liquid ejection head through the nozzle.

[0192] (P) In the above-mentioned method for controlling a liquid ejection device, discharging the waste liquid from the pressure chamber may include driving the supply pump to pressurize the pressure chamber while the suction valve is closed and the pressurization valve and the exhaust valve are open.

[0193] According to this method for controlling a liquid ejection device, the inside of the pressure chamber can be pressurized by driving the supply pump, and waste liquid within the pressure chamber can be discharged. (Q) In the above-mentioned method for controlling the liquid ejection device, discharging the waste liquid from the pressure chamber may include driving the cleaning pump to pressurize the pressure chamber while the suction valve is closed and the pressurization valve and the exhaust valve are open.

[0194] According to this method for controlling a liquid ejection device, the cleaning pump is driven to pressurize the pressure chamber, thereby discharging waste liquid from the pressure chamber. (R) In the above-mentioned method for controlling a liquid ejection device, the discharge valve of the liquid ejection device may be a one-way valve that allows the flow of liquid from upstream to downstream and restricts the flow of liquid from downstream to upstream.

[0195] According to this method for controlling a liquid ejection device, there is no need to provide a mechanism for opening and closing the discharge valve, which makes it possible to simplify the configuration of the liquid ejection device. [Explanation of symbols]

[0196] 11...liquid ejection device, 12...nozzle, 12a...nozzle surface, 13...liquid ejection section, 13a...liquid ejection head, 14...liquid container, 14f...first liquid container, 14s...second liquid container, 20...liquid container, 21...container, 22...outlet flow path, 23...junction flow path, 24f...first valve, 24s...second valve, 25...storage section, 26...connection flow path, 28...gas ejection path, 29...ejection valve, 29f...first ejection valve, 29s...second ejection valve, 31...detection section, 32...movable wall, 33...moving body, 34...first biasing member, 35...lever, 36...second biasing member, 40...supply mechanism, 4 1...first delivery flow path, 42...second delivery flow path, 43...third delivery flow path, 44...supply pump, 45...third delivery valve, 46...fourth delivery valve, 47...delivery flow path, 50...pressure adjustment section, 60...supply regulation section, 61...gas chamber, 62...liquid chamber, 63...projection section, 64...film member, 65...biasing member, 66...first release valve, 67...opening, 70...liquid pressurizing section, 71...gas chamber, 72...liquid chamber, 73...film member, 74...biasing member, 75...second release valve, 80...maintenance section, 81...cleaning mechanism, 82...wiping mechanism, 83...cap, 84...suction mechanism, 85... Discharge flow path, 86...suction valve, 88...wiper, 89...wiper support portion, 90...supply flow path, 91...first supply flow path, 92...second supply flow path, 93...third supply flow path, 94...fourth supply flow path, 95...fifth supply flow path, 100...control portion, 102...main body portion, 103...image reading portion, 104...automatic feed portion, 105...operation portion, 106...medium storage portion, 107...mounting portion, 107a...mounting surface, 111...pressure chamber, 112...discharge valve, 113...pressure sensor, 114...release valve, 115...waste liquid tank, 116...cleaning pump, 117...pressure reduction flow path, 118...pressure reduction valve, 119 ...pressure reduction flow path release valve, 127...pressurized flow path, 128...pressurized valve, 129...pressurized flow path release valve, 130...driving mechanism, 131...first storage container, 134...second storage container, 142...CPU, 143...storage unit, 146...discharge failure detection unit, 147...piezoelectric element drive circuit, 148...cap drive circuit, 149...cleaning pump drive circuit, 150...supply pump drive circuit, 151...suction valve drive circuit, 152...pressurized valve drive circuit, 153...pressure reduction valve drive circuit, 154...release valve drive circuit, 155...discharge valve drive circuit, 220...filter unit, 221...filter,222...upstream filter chamber, 223...downstream filter chamber, 280...liquid pressure adjustment mechanism, 281...communication hole, 282...liquid chamber, 283...valve body, 284...pressure receiving member, 285...flexible wall, 286...first pressing member, 287...second pressing member, 290...valve opening mechanism, 291...accommodation chamber, 292...pressurizing bag, 293...ventilation flow path, 328...mounting portion, 329...accommodation chamber, 330...outlet portion, 331...valve, 334...communication 336...first valve, 337...supply flow path, 338...second valve, 339...recovery flow path, 340...third valve, 341...liquid chamber, 342...flexible member, 344...first connection portion, 345...second connection portion, 348...switching mechanism, 349...pressure sensor, 350...atmospheric release path, 351...pressurized flow path, 352...connecting flow path, 353...air chamber, 354...spring, 355...air flow path, 357...pressurizing mechanism, 358...micro Pressurizing section, 360...introduction section, 361...apparatus side valve, 362...first storage chamber, 363...liquid level sensor, 364...first gas-liquid separation membrane, 365...ceiling, 366...first liquid level, 368...second storage chamber, 369...second gas-liquid separation membrane, 370...second liquid level, 372...narrow tube section, 373a...first selection valve, 373b...second selection valve, 373c...third selection valve, 373d...fourth selection valve, 373e...fifth selection valve, 373f...third 6 selection valve, 373g...7th selection valve, 373h...8th selection valve, 373i...9th selection valve, 373j...10th selection valve, 373k...11th selection valve, CS...closed space, M...medium, np...number of shots, ns...number of suction cleanings, nw...number of pressurized wipings, PL...pressurized threshold, Q1...capacity, Q2...total discharge, Q2p...discharge amount, Q2s...suction amount, Q2w...leakage amount, Q3...remaining amount, QL1...first threshold.

Claims

1. A liquid ejection head having a nozzle capable of ejecting liquid; a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head; a supply pump configured to pressurize the liquid within the liquid container or within the supply channel; a cap configured to define a closed space into which the nozzle opens; a discharge flow path for discharging the liquid received in the cap from the cap; a suction valve disposed in the middle of the discharge flow path and configured to open and close the discharge flow path; a pressure chamber disposed in the discharge flow path downstream of the suction valve; a cleaning pump configured to reduce pressure inside the pressure chamber; a pressure passage communicating with the supply pump and the pressure chamber; a pressurization valve configured to open and close the pressurization flow path; a discharge valve disposed in the discharge flow passage and configured to open and close the discharge flow passage downstream of the pressure chamber; a controller configured to control the supply pump, the cleaning pump, the suction valve, and the pressurization valve; The supply pump is configured to pressurize the pressure chamber through the pressure passage, The liquid ejection device, wherein the control unit is configured to drive the supply pump to pressurize an inside of the supply flow path in order to perform pressurized cleaning to discharge the liquid from the nozzle.

2. A liquid ejection head having a nozzle capable of ejecting liquid; a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head; a supply pump configured to pressurize the liquid within the liquid container or within the supply channel; a cap configured to define a closed space into which the nozzle opens; a discharge flow path for discharging the liquid received in the cap from the cap; a suction valve disposed in the middle of the discharge flow path and configured to open and close the discharge flow path; a pressure chamber disposed in the discharge flow path downstream of the suction valve; a cleaning pump configured to reduce pressure inside the pressure chamber; a pressure passage communicating with the supply pump and the pressure chamber; a pressurization valve configured to open and close the pressurization flow path; a discharge valve disposed in the discharge flow passage and configured to open and close the discharge flow passage downstream of the pressure chamber; a controller configured to control the supply pump, the cleaning pump, the suction valve, and the pressurization valve; The supply pump is configured to pressurize the pressure chamber through the pressure passage, The control unit is configured to reduce the pressure inside the pressure chamber to a negative pressure by driving the cleaning pump with the suction valve, the pressurization valve, and the exhaust valve closing the exhaust flow path, and then open the suction valve to apply the negative pressure inside the pressure chamber to the closed space defined by the cap.

3. A liquid ejection head having a nozzle capable of ejecting liquid; a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head; a supply pump configured to pressurize the liquid within the liquid container or within the supply channel; a cap configured to define a closed space into which the nozzle opens; a discharge flow path for discharging the liquid received in the cap from the cap; a suction valve disposed in the middle of the discharge flow path and configured to open and close the discharge flow path; a pressure chamber disposed in the discharge flow path downstream of the suction valve; a pressure passage communicating with the supply pump and the pressure chamber; a pressurization valve configured to open and close the pressurization flow path; a pressure reduction passage communicating with the supply pump and the pressure chamber; a pressure reducing valve configured to open and close the pressure reducing flow path; a discharge valve disposed in the discharge flow passage and configured to open and close the discharge flow passage downstream of the pressure chamber; a controller configured to control the supply pump, the suction valve, the pressurization valve, and the pressure reduction valve; The supply pump is configured to pressurize the pressure chamber through the pressure passage, The liquid ejection device, wherein the control unit is configured to drive the supply pump to pressurize an inside of the supply flow path in order to perform pressurized cleaning to discharge the liquid from the nozzle.

4. A liquid ejection head having a nozzle capable of ejecting liquid; a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head; a supply pump configured to pressurize the liquid within the liquid container or within the supply channel; a cap configured to define a closed space into which the nozzle opens; a discharge flow path for discharging the liquid received in the cap from the cap; a suction valve disposed in the middle of the discharge flow path and configured to open and close the discharge flow path; a pressure chamber disposed in the discharge flow path downstream of the suction valve; a pressure passage communicating with the supply pump and the pressure chamber; a pressurization valve configured to open and close the pressurization flow path; a pressure passage release valve disposed between the supply pump and the pressure valve; a pressure reduction flow passage communicating with the supply pump and the pressure chamber; A pressure reducing valve configured to open and close the pressure reducing flow path; a discharge valve disposed in the discharge flow passage and configured to open and close the discharge flow passage downstream of the pressure chamber; a controller configured to control the supply pump, the suction valve, the pressurization valve, and the pressure reduction valve; The supply pump is configured to pressurize the pressure chamber through the pressure passage, The control unit is configured to reduce the pressure inside the pressure chamber to a negative pressure by opening the pressure reduction valve and the pressurization flow path open valve and driving the supply pump while the suction valve, the pressurization valve, and the exhaust valve are closing the exhaust flow path, and then open the suction valve to apply the negative pressure inside the pressure chamber to the closed space defined by the cap.

5. A liquid ejection head having a nozzle capable of ejecting liquid; a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head; a cap configured to define a closed space into which the nozzle opens; a discharge flow path for discharging the liquid received in the cap from the cap; a suction valve configured to open and close the exhaust flow path; a pressure chamber disposed in the discharge flow path downstream of the suction valve; a cleaning pump configured to reduce pressure inside the pressure chamber; a pressure passage communicating with the cleaning pump and the pressure chamber; a pressurization valve configured to open and close the pressurization flow path; a discharge valve disposed in the discharge flow passage and configured to open and close the discharge flow passage downstream of the pressure chamber; a controller configured to control the cleaning pump, the suction valve, and the pressurization valve; Equipped with the cleaning pump is configured to pressurize the inside of the pressure chamber through the pressure passage, The control unit is configured to reduce the pressure inside the pressure chamber to a negative pressure by driving the cleaning pump with the suction valve, the pressurization valve, and the exhaust valve closing the exhaust flow path, and then open the suction valve to apply the negative pressure inside the pressure chamber to the closed space defined by the cap.

6. A liquid ejection head having a nozzle capable of ejecting liquid; a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head; a cap configured to define a closed space into which the nozzle opens; a discharge flow path for discharging the liquid received in the cap from the cap; a suction valve configured to open and close the exhaust flow path; a pressure chamber disposed in the discharge flow path downstream of the suction valve; a cleaning pump configured to reduce pressure inside the pressure chamber; a pressure passage communicating with the cleaning pump and the pressure chamber; a pressurization valve configured to open and close the pressurization flow path; a discharge valve disposed in the discharge flow passage and configured to open and close the discharge flow passage downstream of the pressure chamber; a controller configured to control the cleaning pump, the suction valve, and the pressurization valve; Equipped with the cleaning pump is configured to pressurize the inside of the pressure chamber through the pressure passage, The control unit is configured to discharge the waste liquid from the pressure chamber by driving the cleaning pump to pressurize the pressure chamber while the suction valve is closed and the pressure valve and the exhaust valve are open.

7. The control unit is configured to reduce the pressure in the pressure chamber to a negative pressure by driving the cleaning pump with the suction valve, the pressurizing valve, and the exhaust valve closing the exhaust flow path, and then to open the suction valve to apply the negative pressure in the pressure chamber to the closed space defined by the cap.

7. The liquid ejection apparatus according to claim 1, wherein the liquid ejection apparatus is a liquid ejection apparatus.

8. The control unit is configured to discharge the waste liquid from the pressure chamber by driving the supply pump while the suction valve is closed and the pressurizing valve and the discharge valve are open. The liquid ejection device according to any one of claims 1 to 4.

9. The control unit is configured to discharge the waste liquid from the pressure chamber by driving the cleaning pump with the suction valve closed and the pressurizing valve and the discharge valve open.

6. The liquid ejection apparatus according to claim 2 or 5.

10. The discharge valve is a one-way valve that allows the flow of liquid from upstream to downstream and restricts the flow of liquid from downstream to upstream. The liquid ejection device according to any one of claims 1 to 9.

11. A method for controlling a liquid ejection device, the liquid ejection device comprising: A liquid ejection head having a nozzle capable of ejecting liquid; a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head; a supply pump configured to pressurize the liquid within the liquid container or within the supply channel; a cap configured to define a closed space into which the nozzle opens; a discharge flow path for discharging the liquid received in the cap from the cap; a suction valve disposed in the middle of the discharge flow path and configured to open and close the discharge flow path; a pressure chamber disposed in the discharge flow path downstream of the suction valve; a cleaning pump configured to reduce pressure inside the pressure chamber; a pressure passage communicating with the supply pump and the pressure chamber; a pressurization valve configured to open and close the pressurization flow path; a discharge valve disposed in the discharge flow path and configured to open and close the discharge flow path downstream of the pressure chamber, and the control method includes: performing cleaning by pressurizing an inside of the supply flow path by activating the supply pump while the pressurizing valve is closed, and discharging the liquid from the nozzle; discharging the waste liquid from the pressure chamber by driving the supply pump to pressurize the pressure chamber through the pressure passage while the pressure valve is open; A method for controlling a liquid ejection device, comprising:

12. A method for controlling a liquid ejection device, the liquid ejection device comprising: A liquid ejection head having a nozzle capable of ejecting liquid; a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head; a supply pump configured to pressurize the liquid within the liquid container or within the supply channel; a cap configured to define a closed space into which the nozzle opens; a discharge flow path for discharging the liquid received in the cap from the cap; a suction valve disposed in the middle of the discharge flow path and configured to open and close the discharge flow path; a pressure chamber disposed in the discharge flow path downstream of the suction valve; a cleaning pump configured to reduce pressure inside the pressure chamber; a pressure passage communicating with the supply pump and the pressure chamber; a pressurization valve configured to open and close the pressurization flow path; a discharge valve disposed in the discharge flow path and configured to open and close the discharge flow path downstream of the pressure chamber, and the control method includes: driving the cleaning pump while the suction valve and the exhaust valve are in a state of closing the exhaust flow path, thereby reducing the pressure inside the pressure chamber until a negative pressure is reached; After reducing the pressure inside the pressure chamber, the suction valve is opened to apply the negative pressure inside the pressure chamber to the closed space; discharging the waste liquid from the pressure chamber by driving the supply pump to pressurize the pressure chamber through the pressure passage while the pressure valve is open; A method for controlling a liquid ejection device, comprising:

13. A method for controlling a liquid ejection device, the liquid ejection device comprising: A liquid ejection head having a nozzle capable of ejecting liquid; a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head; a supply pump configured to pressurize the liquid within the liquid container or within the supply channel; a cap configured to define a closed space into which the nozzle opens; a discharge flow path for discharging the liquid received in the cap from the cap; a suction valve disposed in the middle of the discharge flow path and configured to open and close the discharge flow path; a pressure chamber disposed in the discharge flow path downstream of the suction valve; a pressure passage communicating with the supply pump and the pressure chamber; a pressurization valve configured to open and close the pressurization flow path; a pressure reduction passage communicating with the supply pump and the pressure chamber; a pressure reducing valve configured to open and close the pressure reducing flow path; a discharge valve disposed in the discharge flow passage and configured to open and close the discharge flow passage downstream of the pressure chamber; The control method includes: performing cleaning by pressurizing an inside of the supply flow path by activating the supply pump while the pressurizing valve is closed, and discharging the liquid from the nozzle; discharging the waste liquid from the pressure chamber by driving the supply pump to pressurize the pressure chamber through the pressure passage while the pressure valve is open; A method for controlling a liquid ejection device, comprising:

14. A method for controlling a liquid ejection device, the liquid ejection device comprising: A liquid ejection head having a nozzle capable of ejecting liquid; a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head; a supply pump configured to pressurize the liquid within the liquid container or within the supply channel; a cap configured to define a closed space into which the nozzle opens; a discharge flow path for discharging the liquid received in the cap from the cap; a suction valve disposed in the middle of the discharge flow path and configured to open and close the discharge flow path; a pressure chamber disposed in the discharge flow path downstream of the suction valve; a pressure passage communicating with the supply pump and the pressure chamber; a pressurization valve configured to open and close the pressurization flow path; a pressure passage release valve disposed between the supply pump and the pressure valve; a pressure reduction flow passage communicating with the supply pump and the pressure chamber; A pressure reducing valve configured to open and close the pressure reducing flow path; a discharge valve disposed in the discharge flow passage and configured to open and close the discharge flow passage downstream of the pressure chamber; The control method includes: driving the supply pump while the suction valve, the pressurizing valve, and the exhaust valve are closed and while the decompression valve and the pressurized flow passage opening valve are open, thereby reducing the pressure inside the pressure chamber until a negative pressure is reached; After reducing the pressure inside the pressure chamber, the suction valve is opened to apply the negative pressure inside the pressure chamber to the closed space defined by the cap; discharging the waste liquid from the pressure chamber by driving the supply pump to pressurize the pressure chamber through the pressure passage while the pressure valve is open; A method for controlling a liquid ejection device, comprising:

15. A method for controlling a liquid ejection device, the liquid ejection device comprising: A liquid ejection head having a nozzle capable of ejecting liquid; a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head; a cap configured to define a closed space into which the nozzle opens; a discharge flow path for discharging the liquid received in the cap from the cap; a suction valve configured to open and close the exhaust flow path; a pressure chamber disposed in the discharge flow path downstream of the suction valve; a cleaning pump configured to reduce pressure inside the pressure chamber; a pressure passage communicating with the cleaning pump and the pressure chamber; a pressurization valve configured to open and close the pressurization flow path; a discharge valve disposed in the discharge flow path and configured to open and close the discharge flow path downstream of the pressure chamber, and the control method includes: driving the cleaning pump while the suction valve and the exhaust valve are in a state of closing the exhaust flow path, thereby reducing the pressure inside the pressure chamber until a negative pressure is reached; After reducing the pressure inside the pressure chamber, the suction valve is opened to apply the negative pressure inside the pressure chamber to the closed space; discharging the waste liquid from the pressure chamber by driving the cleaning pump to pressurize the pressure chamber through the pressure passage while the pressure valve is open; A method for controlling a liquid ejection device, comprising:

16. A method for controlling a liquid ejection device, the liquid ejection device comprising: A liquid ejection head having a nozzle capable of ejecting liquid; a supply flow path for causing liquid in a liquid container to flow toward the liquid ejection head; a cap configured to define a closed space into which the nozzle opens; a discharge flow path for discharging the liquid received in the cap from the cap; a suction valve configured to open and close the exhaust flow path; a pressure chamber disposed in the discharge flow path downstream of the suction valve; a cleaning pump configured to reduce pressure inside the pressure chamber; a pressure passage communicating with the cleaning pump and the pressure chamber; a pressurization valve configured to open and close the pressurization flow path; a discharge valve disposed in the discharge flow path and configured to open and close the discharge flow path downstream of the pressure chamber, and the control method includes: and discharging the waste liquid from the pressure chamber by driving the cleaning pump to pressurize the pressure chamber through the pressure passage while the pressure valve is open. discharging the waste liquid from the pressure chamber includes pressurizing the inside of the pressure chamber by driving the cleaning pump while the suction valve is closed and the pressurizing valve and the discharge valve are open. A method for controlling a liquid ejection device comprising the steps of:

17. driving the cleaning pump while the suction valve and the exhaust valve are in a state of closing the exhaust flow path, thereby reducing the pressure inside the pressure chamber until a negative pressure is reached; After reducing the pressure inside the pressure chamber, the suction valve is opened to apply the negative pressure inside the pressure chamber to the closed space; The method for controlling a liquid ejection device according to claim 11 or 16, further comprising:

18. Discharging the waste liquid from the pressure chamber includes pressurizing the inside of the pressure chamber by driving the supply pump while the suction valve is closed and the pressurizing valve and the discharge valve are open. The method for controlling the liquid ejection device according to any one of claims 11 to 14.

19. Discharging the waste liquid from the pressure chamber includes pressurizing the inside of the pressure chamber by driving the cleaning pump while the suction valve is closed and the pressurizing valve and the discharge valve are open. The method for controlling the liquid ejection device according to claim 12 or 15.

20. The discharge valve is a one-way valve that allows the flow of liquid from upstream to downstream and restricts the flow of liquid from downstream to upstream.

20. The method for controlling the liquid ejection device according to claim 11.

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