Tank unit and liquid ejection device

Abstract

To provide a tank unit which can make liquid level of two storage chambers to a proper height without any need for performing supply control, etc., and a liquid discharge device.SOLUTION: A tank unit 26 comprises: a first introduction part 60 which introduces a liquid supplied from a liquid storage body; a first accumulation chamber 62 which accumulates the liquid introduced from the first introduction part 60; and a first ambient air open part 64 which can open the interior of the first accumulation chamber 62 to ambient air. Further, the tank unit 26 comprises: a lead-out passage 34 of which one end is connected to the first accumulation chamber 62, and which leads out the liquid in the first accumulation chamber 62; a second accumulation chamber 68 which is connected to the other end of the lead-out passage 34, and which accumulates the liquid supplied from the first accumulation chamber 62; and a second ambient air open part 69 which can open the interior of the second accumulation chamber 68 to ambient air. Further, the tank unit 26 comprises an opening / closing valve 36 which can open / close the lead-out passage 34. The first introduction part 60 is connected to the first accumulation chamber 62 via an opening 603 at an intermediate position in a vertical direction Z of the first accumulation chamber 62.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a tank unit that contains liquid and a liquid ejection device including the same. [Background technology]

[0002] Patent Document 1 discloses an inkjet printer as an example of a liquid ejection device equipped with a liquid ejection head that ejects liquid such as ink. This type of liquid ejection device includes a tank unit that contains liquid. A liquid container such as a cartridge is removably attached to the tank unit. The tank unit is configured to be capable of introducing liquid supplied from the liquid container and to be capable of directing the liquid toward the liquid ejection head that is capable of ejecting the liquid. The liquid ejection head ejects the liquid supplied from the tank unit.

[0003] The tank unit disclosed in Patent Document 1 has two storage chambers. One is a first storage chamber that stores the liquid introduced from a liquid container, and the other is a second storage chamber that stores the liquid introduced from the first storage chamber. The liquid ejection head introduces the liquid from the second storage chamber. Furthermore, this tank unit includes a refill valve, a liquid level sensor, and a circulation pump that are controlled by a control unit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-82536 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the liquid ejection device described in Patent Document 1, in order to set the liquid levels in the two storage chambers to appropriate heights, complex supply control by a replenishing valve, a liquid level sensor, and a circulation pump is required. Therefore, there is a demand for a tank unit and a liquid ejection device that can adjust the liquid levels in the two storage chambers to appropriate heights with a simple configuration.

Means for Solving the Problems

[0006] The tank unit for solving the above problems is a tank unit that can introduce the liquid supplied from the liquid container and can lead out the liquid toward the liquid ejection head capable of ejecting the liquid. The tank unit includes a first introduction part for introducing the liquid supplied from the liquid container, a first storage chamber for storing the liquid introduced from the first introduction part, a first atmosphere release part for opening the inside of the first storage chamber to the atmosphere, a lead-out flow path having one end connected to the first storage chamber for leading out the liquid in the first storage chamber, a second storage chamber connected to the other end of the lead-out flow path for storing the liquid supplied from the first storage chamber, a second atmosphere release part for opening the inside of the second storage chamber to the atmosphere, and an opening / closing valve for opening and closing the lead-out flow path. The first introduction part is connected to the first storage chamber through an opening at an intermediate position in the vertical direction of the first storage chamber. , the two storage chambers are provided at a position where the opening is located at a middle position in the vertical direction of the second storage chamber, and one end of the outlet channel is located below the opening. 。

[0007] The liquid ejection device for solving the above problems includes a liquid ejection head capable of ejecting the liquid, the above tank unit, a supply flow path communicating the lead-out part and the liquid ejection head, and a recovery flow path communicating the liquid ejection head and the second introduction part.

Brief Description of the Drawings

[0008]

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Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of a tank unit and a liquid ejection device including the same will be described with reference to the drawings. The liquid ejection device is, for example, an inkjet printer that ejects ink, which is an example of a liquid, onto a medium such as paper for printing.

[0010] In the drawings, it is assumed that the liquid ejection device 11 is placed on a horizontal plane, and the direction of gravity is indicated by the Z-axis, and the directions along the horizontal plane are indicated by the X-axis and the Y-axis. The X-axis, Y-axis, and Z-axis are orthogonal to each other. When the user faces the front of the liquid ejection device 11, the Y-axis indicates the depth direction of the liquid ejection device 11, and the X-axis indicates the width direction of the liquid ejection device 11.

[0011] <Overall Configuration of Liquid Ejection Device> As shown in FIG. 1, the liquid ejection device 11 may include a medium storage unit 13 capable of storing a medium 12, a stacker 14 for receiving the printed medium 12, and an operation unit 15 for operating the liquid ejection device 11. The operation unit 15 may be, for example, a touch panel. The operation unit 15 that is a touch panel may have a display unit 15a capable of displaying various operation screens, various messages, and the like. The liquid ejection device 11 may include an image reading unit 16 for reading an image of a document and an automatic document feeder 17 for feeding the document to the image reading unit 16.

[0012] The liquid ejection device 11 includes a control unit 19 that controls various operations executed by the liquid ejection device 11. The control unit 19 can be configured as a circuitry including 1) one or more processors that operate according to a computer program (software), 2) one or more dedicated hardware circuits such as dedicated hardware (application specific integrated circuit: ASIC) that executes at least a part of various processes, or 3) a combination thereof. The processor includes a CPU and memories such as a RAM and a ROM, and the memories store program codes or instructions configured to cause the CPU to execute processes. The memory, i.e., the computer-readable medium, includes any available medium accessible by a general-purpose or dedicated computer.

[0013] The liquid ejection device 11 includes a tank unit 26. The tank unit 26 may include a mounting portion 28 to which one or more liquid containers 24 are detachably mounted. The mounting portion 28 may have a plurality of slots respectively corresponding to the plurality of liquid containers 24. The mounting portion 28 has an insertion port 28o for inserting the liquid container 24. The insertion port 28o opens, for example, toward the front of the liquid ejection device 11. In this case, the liquid container 24 is inserted through the insertion port 28o, for example, in a direction along the Y-axis from the front of the liquid ejection device 11. The liquid ejection device 11 may include a cover (not shown) that covers the insertion port 28o. This cover may be movable between a position covering the insertion port 28o and a position opening the insertion port 28o.

[0014] The plurality of liquid containers 24 (24C, 24M, 24Y, 24K) may each contain a plurality of liquids of different types, for example, inks of different colors. For example, the liquid containers 24C, 24M, 24Y, 24K may contain cyan, magenta, yellow, and black inks, respectively. The plurality of liquid containers 24 may have different liquid storage capacities from each other. For example, the liquid container 24K that stores black ink may have a larger liquid storage capacity than the other liquid containers 24C, 24M, 24Y. The liquid container 24K may have a greater width, that is, a longer length along the X-axis, than the other liquid containers 24C, 24M, 24Y. Note that the direction in which the liquid container 24 can be inserted into the tank unit 26 is not limited to the direction along the Y-axis, and may be a direction along the X-axis, a direction along the Z-axis, or an oblique direction that intersects at an acute angle with at least one of the XYZ axes.

[0015] <Configuration of Supply Unit 25> Next, with reference to FIG. 2, the configuration of the supply unit 25 will be described. As shown in FIG. 2, the liquid ejection device 11 includes a liquid ejection head 23, a supply unit 25, and a supply channel 37 that supplies liquid from the supply unit 25 to the liquid ejection head 23.

[0016] The supply unit 25 includes a tank unit 26 that includes two storage parts 33, 35 for storing liquid. The supply unit 25 may include a drive mechanism 27 that drives the tank unit 26.

[0017] The tank unit 26 is configured to be able to introduce the liquid supplied from the liquid container 24 and to be able to lead out the liquid toward the liquid discharge head 23 that can discharge the liquid. The tank unit 26 includes a first introduction part 60, a first storage part 33, a second storage part 35, and a lead-out flow path 34 that communicates the first storage part 33 and the second storage part 35. An opening / closing valve 36 is provided in the middle of the lead-out flow path 34. In the liquid flow direction when the liquid is supplied from the liquid container 24 to the liquid discharge head 23, the first storage part 33 is located upstream of the second storage part 35. The first storage part 33 functions as a sub-tank that temporarily stores the liquid introduced from the liquid container 24. The second storage part 35 functions as a reservoir tank that temporarily stores the liquid led out from the first storage part 33 until the liquid is supplied to the liquid discharge head 23.

[0018] The liquid introduced from the liquid container 24 in the mounted state is stored in the first storage part 33. As a result of the liquid in the second storage part 35 being supplied to the liquid discharge head 23 and the liquid in the second storage part 35 being consumed, the opening / closing valve 36 opens, and the liquid is replenished from the first storage part 33 to the second storage part 35 through the lead-out flow path 34. The opening / closing valve 36 may be a one-way valve. The opening / closing valve 36 that is a one-way valve allows the flow of the liquid in the direction of leading out from the first storage chamber 62 to the second storage chamber 68 and blocks the flow of the liquid from the second storage chamber 68 to the first storage chamber 62.

[0019] The first storage part 33 includes a first storage chamber 62 (sub-tank chamber) that stores the liquid supplied from the liquid container 24. Further, the second storage part 35 includes a second storage chamber 68 (reservoir tank chamber) that can store the liquid introduced from the first storage chamber 62 through the lead-out flow path 34 when the opening / closing valve 36 opens. The first storage chamber 62 and the second storage chamber 68 communicate with each other through the above-described lead-out flow path 34. The above-described opening / closing valve 36 provided on the lead-out flow path 34 may be controlled by the control unit 19, but in this embodiment, it is constituted by a differential pressure valve that can be opened and closed by a water head difference. The detailed configuration of the opening / closing valve 36 will be described later.

[0020] As shown in FIG. 2, the tank unit 26 configured as described above includes a first introduction section 60, a first storage chamber 62, a discharge channel 34, a second storage chamber 68, and an opening / closing valve 36, and further includes a first air release section 64 and a second air release section 69. The first air release section 64 is configured to be able to open the inside of the first storage chamber 62 to the atmosphere. The first air release section 64 opens into a space above the first liquid level 66, which is the liquid level of the liquid stored in the first storage chamber 62. Also, the second air release section 69 is configured to be able to open the second storage chamber 68 to the atmosphere. The second air release section 69 opens into a space above the second liquid level 70, which is the liquid level of the liquid stored in the second storage chamber 68.

[0021] The first air release section 64 may be configured to be switchable between an air release state in which the inside of the first storage chamber 62 is opened to the atmosphere and a non-air release state in which the inside of the first storage chamber 62 is not opened to the atmosphere. Also, the second air release section 69 may be configured to be switchable between an air release state in which the inside of the second storage chamber 68 is opened to the atmosphere and a pressurized state in which the inside of the second storage chamber 68 can be pressurized at a pressure higher than the atmospheric pressure.

[0022] The liquid ejection device 11 includes a liquid ejection head 23 capable of ejecting a liquid, a tank unit 26 configured as described above, and a supply channel 37 that communicates the tank unit 26 and the liquid ejection head 23. The liquid in the tank unit 26 is supplied to the liquid ejection head 23 through the supply channel 37. The liquid ejection head 23 ejects the liquid supplied from the tank unit 26 through the supply channel 37. Further, the liquid ejection device 11 may include a recovery channel 39 that communicates the liquid ejection head 23 and the tank unit 26. That is, the liquid ejection device 11 may include a supply channel 37 that supplies the liquid in the tank unit 26 to the liquid ejection head 23 and a recovery channel 39 that recovers the liquid from the liquid ejection head 23 to the tank unit 26. Thus, the liquid ejection device 11 may be configured to circulate the liquid between the tank unit 26 and the liquid ejection head 23 through the supply channel 37 and the recovery channel 39.

[0023] For example, a liquid heated by a heater (not shown) may be circulated between the tank unit 26 and the liquid discharge head 23 so that a liquid at a predetermined temperature can be discharged from the liquid discharge head 23. Further, when the liquid is a liquid composed of a pigment-based ink, by circulating the liquid between the tank unit 26 and the liquid discharge head 23, the sedimentation of the pigment in the liquid can be suppressed by the stirring action of the liquid due to circulation, and a liquid in which the pigment is uniformly dispersed can be discharged from the liquid discharge head 23. Of course, for other purposes, the liquid may be circulated between the tank unit 26 and the liquid discharge head 23.

[0024] The liquid discharge device 11 may include a liquid discharge head 23, a tank unit 26, a supply channel 37, a second introduction part 75, and a recovery channel 39. The tank unit 26 may include a derivation part 74 that derives the liquid stored therein to the liquid discharge head 23 through the supply channel 37, and a second introduction part 75 that introduces the liquid recovered from the liquid discharge head 23 through the recovery channel 39. The supply channel 37 communicates the derivation part 74 and the liquid discharge head 23. The recovery channel 39 communicates the liquid discharge head 23 and the second introduction part 75.

[0025] As shown in FIG. 2, when the liquid discharge device 11 adopts a liquid circulation method, a configuration may be adopted in which the liquid in the second storage chamber 68 is derived to the liquid discharge head 23 through the supply channel 37, and the liquid from the liquid discharge head 23 is introduced into the first storage chamber 62 through the recovery channel 39. In this case, the derivation part 74 may be provided in the second storage part 35, and the second introduction part 75 may be provided in the first storage part 33 (see FIGS. 8 and 10).

[0026] The liquid discharge head 23 has one or more nozzles 22 and a nozzle surface 21 through which these nozzles 22 open. The tank unit 26 is configured to supply the liquid stored in the liquid container 24 to the liquid discharge head 23 through the first storage part 33, the derivation channel 34, the second storage part 35, and the supply channel 37. The liquid discharge head 23 is configured to discharge the supplied liquid from the nozzles 22.

[0027] If the liquid ejection device 11 includes a plurality of supply units 25 corresponding to different colors, it can eject inks of a plurality of colors to perform color printing. One drive mechanism 27 may drive a plurality of tank units 26 collectively. The liquid ejection device 11 may include a plurality of drive mechanisms 27 that individually drive the plurality of tank units 26.

[0028] The liquid ejection head 23 may be detachably provided with respect to the main body of the liquid ejection device 11. The liquid ejection head 23 may be arranged so as to be in an inclined posture in which the nozzle surface 21 is inclined with respect to the horizontal. The liquid ejection head 23 may execute printing by ejecting liquid with respect to the medium 12 in the inclined posture. The liquid ejection head 23 may be a line type provided across the width direction of the medium 12. The liquid ejection head 23 may be a serial type that performs printing while moving in the width direction of the medium 12.

[0029] The liquid container 24 may include a storage chamber 29 that stores liquid. The liquid stored in the storage chamber 29 is led out through the pouring portion 30. The pouring portion 30 may have a lead-out valve 31. The storage chamber 29 is, for example, a sealed space not communicating with the atmosphere. The liquid container 24 before being mounted on the mounting portion 28 may store an amount of liquid larger than the amount of liquid that the tank unit 26 can hold.

[0030] The supply unit 25 may include a supply valve 38 that can close the supply flow path 37, a recovery flow path 39, a circulation valve 40 that can open and close the recovery flow path 39, and a liquid chamber 41. The liquid chamber 41 is arranged in the middle of the recovery flow path 39. The recovery flow path 39 has an upstream end connected to the liquid ejection head 23 and a downstream end connected to the first storage portion 33. The recovery flow path 39 is a flow path for flowing the liquid in the liquid ejection head 23 toward the inside of the tank unit 26.

[0031] The liquid chamber 41 is arranged in the middle of the recovery flow path 39, that is, between the liquid ejection head 23 and the circulation valve 40. A part of the liquid chamber 41 is defined by a flexible member 42. When the flexible member 42 bends and deforms, the volume of the liquid chamber 41 changes.

[0032] The liquid ejection head 23 may have a first connection portion 44 to which the recovery flow path 39 is connected and a second connection portion 45 to which the supply flow path 37 is connected. The recovery flow path 39 has an upstream end connected to the first connection portion 44 and a downstream end connected to the first storage portion 33. The supply flow path 37 has an upstream end connected to the second storage portion 35 and a downstream end connected to the second connection portion 45. When the liquid ejection head 23 is in an inclined posture, the first connection portion 44 may be disposed at a position higher than the second connection portion 45.

[0033] As shown in FIG. 2, the liquid ejection device 11 may further include a pressurizing portion 47 that communicates with the second atmosphere release portion 69 and can pressurize the inside of the second storage chamber 68. That is, the drive mechanism 27 may include a pressurizing portion 47 that can pressurize the inside of the second storage portion 35. The drive mechanism 27 may include a switching mechanism 48 connected to the pressurizing portion 47 and a pressure sensor 49 that detects pressure. The drive mechanism 27 may include an atmosphere release path 50 connected to the first storage portion 33, a pressurizing flow path 51 connected to the second storage chamber 68, and a connection flow path 52 that connects the atmosphere release path 50 and the pressurizing flow path 51 to the pressurizing portion 47. The drive mechanism 27 may include an air chamber 53 separated from the liquid chamber 41 via a flexible member 42, a spring 54 provided in the air chamber 53, and an air flow path 55 connected to the air chamber 53. The spring 54 reduces pressure fluctuations of the liquid in the recovery flow path 39 and the liquid ejection head 23 by pushing the flexible member 42.

[0034] The pressurizing portion 47 is, for example, a tube pump having a roller and a tube. In this case, air is sent out by the roller rotating while crushing the tube. A tube (not shown) included in the pressurizing portion 47 has a first end connected to the air flow path 55 and a second end connected to the connection flow path 52. The pressurizing portion 47 sends out the air taken in from the air flow path 55 to the connection flow path 52 when driven in the forward direction. The pressurizing portion 47 sends out the air taken in from the connection flow path 52 to the air flow path 55 when driven in the reverse direction.

[0035] The supply unit 25 may include a pressurizing mechanism 57 configured to pressurize the liquid in the supply channel 37. The pressurizing mechanism 57 includes, for example, a pressurizing portion 47, an air chamber 53, and an air channel 55. The supply unit 25 may include a micro-pressurizing portion 58 disposed in the middle of the recovery channel 39, between the liquid discharge head 23 and the circulation valve 40. The micro-pressurizing portion 58 includes the pressurizing mechanism 57 and the liquid chamber 41, and is configured to pressurize the liquid in the recovery channel 39. More specifically, the pressurizing mechanism 57 pressurizes the flexible member 42 from the outside of the liquid chamber 41.

[0036] <First storage portion 33> Next, the first storage portion 33 will be described. The first storage portion 33 may include a first introduction portion 60, a first storage chamber 62, a liquid level detection portion 63, and a first atmosphere release portion 64. The first introduction portion 60 may include an introduction valve 61.

[0037] When the liquid container 24 is attached to the attachment portion 28 (see FIG. 1) of the tank unit 26, the pouring portion 30 and the first introduction portion 60 are coupled, and the discharge valve 31 and the introduction valve 61 are opened. When the liquid container 24 is attached to the attachment portion 28, both valves 31, 61 are held in the open state. In the process of attaching the liquid container 24 to the attachment portion 28, the introduction valve 61 may open before the discharge valve 31. Then, it becomes difficult for the liquid to leak from the liquid container 24.

[0038] The first introduction portion 60 introduces the liquid supplied from the liquid container 24. The first introduction portion 60 may be disposed above the first storage portion 33. The first introduction portion 60 may penetrate, for example, the ceiling 65 of the first storage chamber 62. The lower end of the first introduction portion 60 may be disposed in the first storage chamber 62 and may be located below the ceiling 65. The upper end of the first introduction portion 60 may be disposed outside the first storage chamber 62 and may be located above the ceiling 65. An example of the detailed configuration of the first introduction portion 60 and the first storage chamber 62 will be described later.

[0039] The first storage chamber 62 stores the liquid introduced from the first introduction part 60. The lower end of the first introduction part 60 is located below the nozzle surface 21. Therefore, the first liquid level 66 of the liquid stored in the first storage chamber 62 fluctuates within a range lower than the nozzle surface 21. Specifically, the liquid in the liquid container 24 flows into the first storage part 33 through the pouring part 30 and the first introduction part 60 due to the head difference with the liquid in the first storage part 33.

[0040] The first atmosphere release part 64 is configured to be able to release the inside of the first storage chamber 62 to the atmosphere. The first atmosphere release part 64 is composed of, for example, a gas-liquid separation membrane. Here, the gas-liquid separation membrane is a membrane material having a function of blocking the permeation of liquid and allowing the permeation of gas. The first atmosphere release part 64 allows the air to enter and exit between the first storage chamber 62 and the outside while preventing the liquid in the first storage chamber 62 from leaking to the outside. Since the first storage chamber 62 is thus open to the atmosphere, the first liquid level 66 changes due to the introduction of the liquid from the liquid container 24 through the first introduction part 60 and the discharge of the liquid through the discharge flow path 34.

[0041] One end of the discharge flow path 34 is connected to the first storage chamber 62 to discharge the liquid in the first storage chamber 62. The on-off valve 36 is configured to be able to open and close the discharge flow path 34. The on-off valve 36 may include a one-way valve that allows the flow of liquid from the first storage chamber 62 to the second storage chamber 68 and restricts the flow in the direction from the second storage chamber 68 to the first storage chamber 62. The detailed configuration of the on-off valve 36 will be described later.

[0042] When the liquid in the liquid container 24 flows into the first storage portion 33 through the pouring portion 30 and the first introduction portion 60, an amount of air corresponding to the amount of the liquid flowing into the first storage portion 33 flows from the first storage portion 33 into the liquid container 24 through the first introduction portion 60 and the pouring portion 30. At the same time, the first liquid level 66 rises by the amount of the liquid that has flowed in. When the risen first liquid level 66 reaches the lower end of the first introduction portion 60, the inflow of air from the first storage portion 33 into the liquid container 24 stops. Since the storage chamber 29 is sealed, when the inflow of air stops, the pressure in the storage chamber 29 decreases by the amount of the liquid that has flowed in. When the negative pressure in the storage chamber 29 becomes greater than the water head of the liquid in the storage chamber 29, the inflow of the liquid from the liquid container 24 into the first storage portion 33 stops.

[0043] When the liquid flows from the first storage portion 33 to the second storage portion 35, the first liquid level 66 drops. When the dropped first liquid level 66 falls below the lower end of the first introduction portion 60, air flows into the storage chamber 29 through the first introduction portion 60 and the pouring portion 30, and the negative pressure in the storage chamber 29 decreases. When the negative pressure in the storage chamber 29 becomes smaller than the water head of the liquid in the storage chamber 29, the liquid in the liquid container 24 flows into the first storage portion 33. As a result, while there is liquid in the liquid container 24, the first liquid level 66 is maintained at the standard position SH, which is a position near the lower end of the first introduction portion 60. When the liquid in the liquid container 24 runs out, the first liquid level 66 drops below the standard position SH.

[0044] The tank unit 26 further includes a liquid level detection portion 63 capable of detecting the liquid level of the liquid in the first storage chamber 62. The liquid level detection portion 63 may detect that the first liquid level 66 is located at the standard position, that the first liquid level 66 is located below the standard position, and that the first liquid level 66 is located at the full position. The full position is a position above the standard position SH. When the first liquid level 66 is located at the full position, the first storage portion 33 stores the maximum amount of liquid. When the liquid level detection portion 63 detects that the first liquid level 66 is located below the standard position SH, the control portion 19 may determine that the liquid container 24 has become empty and instruct the user to replace the liquid container 24.

[0045] The standard position SH is set, for example, above the downstream end of the recovery channel 39 in the first storage chamber 62. In this case, when the first liquid level 66 is at the standard position SH, the liquid in the first storage section 33 can flow into the liquid discharge head 23 through the recovery channel 39.

[0046] <Configuration of the second storage section 35> Next, the second storage section 35 will be described. The second storage chamber 68 is connected to the other end of the derivation channel 34 and stores the liquid supplied from the first storage chamber 62. The second storage section 35 may include a second storage chamber 68 and a second atmosphere release section 69 that separates the second storage chamber 68 from the pressurization channel 51.

[0047] The second atmosphere release section 69 is configured to be able to open the inside of the second storage chamber 68 to the atmosphere. The second atmosphere release section 69 is constituted by, for example, a gas-liquid separation membrane. This gas-liquid separation membrane is a membrane material that has a function of allowing gas to permeate while preventing the permeation of liquid, similar to the gas-liquid separation membrane that constitutes the first atmosphere release section 64.

[0048] The liquid in the first storage section 33 flows into the second storage chamber 68 due to the head difference with the liquid in the second storage section 35. When the pressures in the first storage chamber 62 and the second storage chamber 68 are atmospheric pressure, the second liquid level 70 of the liquid stored in the second storage section 35 becomes the same height as the first liquid level 66. In other words, the second liquid level 70 is maintained at the standard position SH that is approximately the same height as the lower end of the first introduction section 60 and fluctuates within a range lower than the nozzle surface 21. The liquid in the liquid discharge head 23 is maintained at a negative pressure due to the head difference with the liquid in the first storage section 33 and the liquid in the second storage section 35. When the liquid is consumed by the liquid discharge head 23, the liquid stored in the second storage section 35 is supplied to the liquid discharge head 23.

[0049] When the on-off valve 36 includes a one-way valve, the one-way valve closes the derivation channel 34 when the pressure in the second storage section 35 is greater than the pressure in the first storage section 33. Therefore, when the pressurization section 47 pressurizes the inside of the second storage section 35, the one-way valve closes the derivation channel 34.

[0050] The control unit 19 (see FIG. 1) controls the opening and closing operations of the supply valve 38 and the circulation valve 40. The supply valve 38 can open and close the supply flow path 37 when pressurized by the pressurizing unit 47. The circulation valve 40 can open and close the recovery flow path 39.

[0051] <Configuration of the switching mechanism 48> Next, the switching mechanism 48 will be described. The switching mechanism 48 includes a capillary part 72 which is a part of the connection flow path 52, and first selection valves 73a to 11th selection valves 73k. The capillary part 72 is a thin and meandering tube such that the flow of liquid is greatly restricted with respect to the flow of air.

[0052] When the first selection valve 73a opens, the air flow path 55 communicates with the atmosphere. When the second selection valve 73b opens, the air flow path 55 communicates with the pressure sensor 49. When the third selection valve 73c opens, the air flow path 55 opens and the pressurizing unit 47 communicates with the air chamber 53.

[0053] When the fourth selection valve 73d opens, the connection flow path 52 between the pressurizing unit 47 and the eighth selection valve 73h communicates with the atmosphere. When the fifth selection valve 73e opens, the connection flow path 52 communicates with the pressure sensor 49. When the sixth selection valve 73f and the seventh selection valve 73g open, the connection flow path 52 communicates with the atmosphere. When the eighth selection valve 73h opens, the connection flow path 52 opens. When the ninth selection valve 73i opens, the capillary part 72 communicates with the atmosphere. When the tenth selection valve 73j opens, the atmosphere release path 50 opens and the first storage part 33 communicates with the connection flow path 52. When the 11th selection valve 73k opens, the pressurization flow path 51 opens and the second storage part 35 communicates with the connection flow path 52.

[0054] When changing the pressure in the air chamber 53, the switching mechanism 48 opens the second to fourth selection valves 73b to 73d and closes the other selection valves. When the pressurizing section 47 is driven to rotate forward in this state, the air in the air chamber 53 is discharged through the air flow path 55 and the connection flow path 52, and the pressure in the air chamber 53 decreases. When the pressurizing section 47 is driven to rotate reversely in this state, air is sent into the air chamber 53 through the connection flow path 52 and the air flow path 55, and the pressure in the air chamber 53 increases. At this time, the pressure sensor 49 may detect the pressure in the air flow path 55 and the air chamber 53. The control unit 19 (see FIG. 1) may control the driving of the pressurizing section 47 based on the detection result of the pressure sensor 49.

[0055] When releasing the first storage section 33 to the atmosphere, the switching mechanism 48 opens the sixth selection valve 73f and the tenth selection valve 73j. The first storage chamber 62 communicates with the atmosphere through the atmosphere release path 50 and the connection flow path 52.

[0056] When releasing the second storage section 35 to the atmosphere, the switching mechanism 48 opens the seventh selection valve 73g and the eleventh selection valve 73k. The second storage chamber 68 communicates with the atmosphere through the pressurizing flow path 51 and the connection flow path 52.

[0057] When pressurizing the inside of the second storage section 35, the switching mechanism 48 opens the first selection valve 73a, the fifth selection valve 73e, the eighth selection valve 73h, and the eleventh selection valve 73k, and closes the other selection valves. When the pressurizing section 47 is driven to rotate forward in this state, air flows into the second storage chamber 68 through the air flow path 55, the connection flow path 52, and the pressurizing flow path 51, and the pressure in the second storage chamber 68 increases. At this time, the pressure sensor 49 may detect the pressure in the connection flow path 52, the pressurizing flow path 51, and the second storage chamber 68. The control unit 19 may control the driving of the pressurizing section 47 based on the detection result of the pressure sensor 49.

[0058] <Configuration of the liquid container 24> Next, with reference to FIGS. 3 and 4, the configuration of the liquid container 24 will be described. As shown in FIGS. 3 and 4, the liquid container 24 is, for example, a cartridge having a first end wall 142, an upper wall 143, a bottom wall 144, a first side wall 145, a second side wall 146, and a second end wall 147. When the liquid container 24 is attached to the liquid ejection device 11, it starts to be inserted first from the first end wall 142.

[0059] As shown in FIG. 3, the liquid container 24 may have an identification portion 430 on the bottom wall 144 for identifying the type of the liquid container 24. The identification portion 430 may be, for example, a plurality of protrusions arranged in the width direction.

[0060] The liquid container 24 may have a positioning hole 448 in the bottom wall 144. The positioning hole 448 may be a recess that opens in the bottom wall 144. The liquid container 24 may have a pouring-out portion 30 that opens in the bottom wall 144. The liquid stored in the liquid container 24 is led out from the liquid container 24 through the pouring-out portion 30. The liquid container 24 may have a release portion 241 that protrudes downward from the bottom wall 144. The release portion 241, the positioning hole 448, and the pouring-out portion 30 may be arranged in this order from the second end wall 147 toward the first end wall 142.

[0061] As shown in FIG. 3, the liquid container 24 may have a circuit board 150 at a portion where the bottom wall 144 and the first end wall 142 intersect and the corner is cut out. The circuit board 150 may have a connection terminal 521 and a storage medium 525. The storage medium 525 may store information about the liquid container 24, for example, information about the liquid stored in the liquid container 24.

[0062] The liquid container 24 may have two receiving portions 447 extending along the Y-axis on the first side wall 145 and the second side wall 146, respectively. In each of the side walls 145, 146, the receiving portion 447 may include a first receiving portion 447a and a second receiving portion 447b having different heights. The first receiving portion 447a may be a groove extending along the bottom wall 144. The second receiving portion 447b is at a position higher than the first receiving portion 447a and has a shorter length along the Y-axis than the first receiving portion 447a. The second receiving portion 447b may be arranged near the circuit board 150.

[0063] As shown in FIG. 4, the liquid container 24 has an engaging portion 497 with the second end wall 147. The engaging portion 497 is, for example, a recess that is disposed above the release portion 241 and opens to the second end wall 147. The engaging portion 497 may be disposed at the center in the width direction of the second end wall 147.

[0064] <Configuration of the mounting portion 28> As shown in FIG. 5, the mounting portion 28 includes a box-shaped frame 80, a support member 90, a rotation shaft 91, and a first introduction portion 60. The support member 90, the rotation shaft 91, and the first introduction portion 60 are disposed within the frame 80. The liquid container 24 is inserted into the frame 80 through the insertion port 28o and moves toward the back of the frame 80. The moving direction of the liquid container 24 at this time, that is, the insertion direction into the mounting portion 28, is along the Y-axis.

[0065] The support member 90 extends along a linear guide path 82 (shown by a white arrow in FIG. 5) that intersects the vertical line (Z-axis). The guide path 82 extends along the moving direction (Y-axis). The support member 90 has a tip region where the start end of the guide path 82 is located and a base end region where the end of the guide path 82 is located. The base end region of the support member 90 and the rotation shaft 91 are disposed at the inner back of the frame 80, that is, at a position away from the insertion port 28o. The support member 90 may have a bottom plate 90a and two side ribs 90b. The two side ribs 90b are respectively disposed at both ends of the bottom plate 90a in the width direction.

[0066] The rotation shaft 91 has an axis that intersects both the vertical line (Z-axis) and the guide path 82 (Y-axis) and is disposed in the base end region of the support member 90. The axis of the rotation shaft 91 extends along the X-axis. The support member 90 is configured to rotate about the rotation shaft 91 between a guide position (shown by a dashed line in FIG. 5) where the liquid container 24 is guided along the guide path 82 and a connection position (shown by a double-dashed line in FIG. 5) where the liquid container 24 is connected to the first introduction portion 60.

[0067] The first introduction part 60 is disposed below the support member 90. When the support member 90 is disposed at the connection position, the first introduction part 60 is connected to the liquid container 24. The first introduction part 60 may be disposed in a posture inclined with respect to the guide path 82 (horizontal). More specifically, the first introduction part 60 may be inclined such that its tip (upper end) is disposed closer to the insertion port 28o than its base end (lower end). For example, the axis of the first introduction part 60 may form an angle in the range greater than 0° and less than or equal to 15° with respect to the vertical line (Z-axis).

[0068] The support member 90 may have one or more guiding parts 247 for guiding the movement of the liquid container 24. The guiding part 247 may be, for example, a pair of guide rails disposed on the opposing side ribs 90b, or a single guide rail disposed on the bottom plate 90a.

[0069] The guiding part 247 may have a first guiding part 247a and a second guiding part 247b disposed to engage with the first receiving part 447a and the second receiving part 447b, respectively. The guiding parts 247a, 247b may be, for example, protrusions extending in the longitudinal direction of the support member 90. The second guiding part 247b is at a higher position than the first guiding part 247a and has a shorter length along the longitudinal direction than the first guiding part 247a. The second guiding part 247b may be disposed closer to the rotation axis 91 than the first guiding part 247a. The first guiding part 247a may be disposed at a position corresponding to the first introduction part 60 in the moving direction of the liquid container 24.

[0070] The mounting part 28 may include a first biasing member 83 that biases the support member 90 from the connection position toward the guiding position. The first biasing member 83 is, for example, a coil spring. In the initial state where the liquid container 24 is not within the mounting part 28, the support member 90 is disposed at the guiding position by being biased by the first biasing member 83.

[0071] As shown in FIG. 6, the mounting portion 28 may have a positioning protrusion 248 that protrudes upward near the first introduction portion 60. The liquid container 24 is positioned when the positioning hole 448 engages with the positioning protrusion 248. The positioning protrusion 248 may be inclined at the same angle as the first introduction portion 60. The bottom plate 90a (see FIG. 5) has a portion corresponding to above the positioning protrusion 248 and the first introduction portion 60 cut out.

[0072] As shown in FIG. 6, the mounting portion 28 may include an engagement lever 84 disposed to face the tip of the support member 90. The engagement lever 84, the positioning protrusion 248, and the first introduction portion 60 may be arranged in this order along the Y-axis. The engagement lever 84 may have a base end (lower end) fixed to the frame 80 and a tip end (upper end). The mounting portion 28 may include a second biasing member 85 that biases the tip of the engagement lever 84 toward the support member 90.

[0073] The engagement lever 84 is arranged to engage with the liquid container 24 supported by the support member 90 when the support member 90 is in the connection position. The engagement lever 84 may have a first inclined surface 86 that extends obliquely downward from the tip and a second inclined surface 87 that extends obliquely downward from the lower end of the first inclined surface 86. The first inclined surface 86 and the second inclined surface 87 define a protrusion that protrudes toward the support member 90.

[0074] The first inclined surface 86 engages with the liquid container 24 when the support member 90 rotates along the rotation path from the guide position (the position shown in FIG. 6) to the connection position (the position shown in FIG. 7). The second inclined surface 87 engages with the liquid container 24 when the support member 90 is in the connection position and when the support member 90 rotates from the connection position toward the guide position.

[0075] Next, with reference to FIGS. 6 and 7, the configuration of the discharge valve 31 of the discharge portion 30 and the introduction valve 61 of the first introduction portion 60 will be described. As shown in FIG. 6, the discharge valve 31 on the side of the liquid container 24 includes a valve body 31a and an elastic member 31b that biases the valve body 31a outward (downward in FIG. 6). The discharge valve 31 closes when the valve body 31a is positioned at the closed valve position closer to the outside shown in FIG. 6 due to the biasing force of the elastic member 31b. Further, as shown in FIG. 7, the discharge valve 31 opens when the valve body 31a is pushed inward (upward in FIG. 7) against the biasing force of the elastic member 31b.

[0076] Also, as shown in FIG. 6, the introduction valve 61 on the side of the first introduction portion 60 includes a valve body 61a and an elastic member 61b that biases the valve body 61a outward (upward in FIG. 6). The introduction valve 61 closes when the valve body 61a is positioned at the closed valve position closer to the outside shown in FIG. 6 due to the biasing force of the elastic member 61b. Further, as shown in FIG. 7, the introduction valve 61 opens when the valve body 61a is pushed inward (downward in FIG. 7) against the biasing force of the elastic member 61b.

[0077] As shown in FIG. 6, the valve body 31a of the discharge valve 31 has a protrusion 31c at its tip. As shown in FIG. 7, in a state where the liquid container 24 is attached to the attachment portion 28, the protrusion 31c of the valve body 31a pushes the valve body 61a of the introduction valve 61 inward (downward in FIG. 7). At this time, the valve body 31a of the discharge valve 31 is pushed upward. As a result, in a state where the liquid container 24 is attached to the attachment portion 28, the discharge valve 31 and the introduction valve 61 are both in an open state, and the pouring portion 30 and the first introduction portion 60 are connected.

[0078] <Operation of the supply unit 25> The operation when the liquid container 24 is attached to the supply unit 25 will be described. As shown in FIG. 5, the liquid container 24 is inserted into the frame 80 through the insertion port 28o. When the first receiving portion 447a of the liquid container 24 engages with the first guiding portion 247a within the frame 80, the liquid container 24 is guided by the first guiding portion 247a and moves horizontally along the guiding path 82 along the Y-axis. At this time, the movement of the liquid container 24 in the width direction is restricted by the two first guiding portions 247a arranged in the width direction. Also, during the movement along the guiding path, the upward movement of the liquid container 24 is restricted by the frame 80, and the downward movement of the liquid container 24 is restricted by the lock lever 92 (see FIG. 7).

[0079] When the liquid container 24 reaches near the end of the guiding path 82, the second receiving portion 447b engages with the second guiding portion 247b. In the vertical direction Z, an electrical connection portion (not shown) may be arranged between the first guiding portion 247a and the second guiding portion 247b. In this case, the connection terminal 521 is properly positioned in the vertical direction Z toward the electrical connection portion. The liquid container 24 may be positioned in the width direction by the identification shape arranged near the electrical connection portion.

[0080] When the liquid container 24 reaches the end of the guiding path 82, the connection terminal 521 comes into contact with the electrical connection portion. Thereby, data communication becomes possible between the circuit board 150 and the control unit 19 (see FIG. 1). At this time, the second end wall 147 of the liquid container 24 is exposed outside the frame 80 or is in a position operable from outside the frame 80.

[0081] Subsequently, while the operator presses the liquid container 24 in the insertion direction against the biasing force of the fourth biasing member (not shown), the operator presses the rear end (the right end in FIG. 5) of the liquid container 24 downward. Then, the support member 90 rotates clockwise in FIG. 4 about the rotation axis 91 against the biasing force of the first biasing member 83. In the process of the rotation of the liquid container 24, first, the positioning protrusion 248 enters the positioning hole 448 (see FIGS. 6 and 7), and subsequently, the pouring portion 30 is connected to the first introducing portion 60.

[0082] At this time, as the biasing spring (not shown) expands and contracts, while maintaining the connection between the connection terminal 521 and the electrical connection portion (not shown), a slight displacement of the liquid container 24 along the Y-axis is allowed. Since the positioning protrusion 248 is disposed near the first introduction portion 60 and is inclined at the same angle as the first introduction portion 60, the pouring portion 30 is appropriately guided toward the first introduction portion 60.

[0083] In the process of the support member 90 rotating to the connection position, the liquid container 24 supported by the support member 90 comes into contact with the first inclined surface 86 of the engagement lever 84. The upper end of the engagement lever 84 pushed by the liquid container 24 is displaced so as to deviate outward (to the right in FIG. 5) from the rotation path of the support member 90 against the biasing force of the second biasing member 85. When the protrusion of the engagement lever 84 engages with the engagement portion 497 of the liquid container 24, the support member 90 stays at the connection position by the biasing force of the second biasing member 85. Thereby, the mounting of the liquid container 24 is completed.

[0084] As shown in FIG. 7, when the mounting of the liquid container 24 is completed, the pouring portion 30 is connected to the first introduction portion 60. At this time, both the discharge valve 31 and the introduction valve 61 are in an open state. Since the liquid container 24 is disposed above the first introduction portion 60, due to the head difference, the liquid in the liquid container 24 is introduced into the first storage portion 33 through the first introduction portion 60.

[0085] Next, the operation when removing the liquid container 24 from the supply unit 25 will be described. When removing the liquid container 24 from the mounting portion 28, the rear end (the right end in FIG. 5) of the liquid container 24 is pulled upward against the biasing force of the second biasing member 85. At this time, since the engagement portion 497 engages with the second inclined surface 87, the support member 90 smoothly rotates together with the liquid container 24. When the protrusion of the engagement lever 84 disengages from the engagement portion 497, the support member 90 rotates from the connection position to the guide position about the rotation shaft 91 by the biasing force of the first biasing member 83.

[0086] In the process of the support member 90 rotating from the connection position to the guiding position, the pouring part 30 moves away from the first introduction part 60, and the positioning projection 248 disengages from the positioning hole 448. At this time, in the process of the pouring part 30 moving away from the first introduction part 60, both the discharge valve 31 and the introduction valve 61 close. Also, when the support member 90 reaches the guiding position, the liquid container 24 is pushed out toward the start end of the guiding path by the biasing force of a fourth biasing member (not shown). At this time, since the liquid container 24 is guided by the first guiding part 247a and the second guiding part 247b, the connection terminal 521 can quickly separate from the electrical connection part (not shown) on the mounting part 28 side without being bent. At the same time, the release part 241 separates from the first arm (not shown), and the lock lever 92 returns to the locked position by the biasing force of a third biasing member (not shown).

[0087] After that, when the operator pulls the liquid container 24 outward from the frame 80, the liquid container 24 is guided by the first guiding part 247a. At this time, since the rotation of the support member 90 is restricted by the lock lever 92, the liquid container 24 moves horizontally along the Y-axis without contacting the first introduction part 60.

[0088] <Detailed configuration of the tank unit 26> Next, with reference to FIGS. 8 and 10, the detailed configuration of the tank unit 26 will be described. As shown in FIGS. 8 and 10, the tank unit 26 includes a first introduction part 60, a first storage chamber 62, and a second storage chamber 68. Note that the first storage chamber 62 and the second storage chamber 68 are formed as chambers by attaching films F1 and F2 to the side surfaces of a synthetic resin frame that constitutes the storage part of the tank unit 26.

[0089] The first introduction part 60 is configured to be connectable to the liquid container 24 (see FIG. 2) mounted on the mounting part 28. When the liquid container 24 is mounted on the mounting part 28, the first introduction part 60 is connected to the pouring part 30 (see FIG. 2) of the liquid container 24. In this mounted state, the liquid from the liquid container 24 is introduced into the first storage chamber 62 through the first introduction part 60.

[0090] As shown in FIGS. 8 and 10, the first introduction part 60 is connected to the first storage chamber 62 through an opening 603 at an intermediate position in the vertical direction Z of the first storage chamber 62. The first introduction part 60 has an introduction path 601 that serves as a flow path for the liquid introduced from the liquid container 24. The introduction path 601 may extend obliquely downward with respect to the vertical direction Z as shown in FIGS. 8 and 10, or may extend in the vertical direction Z. The first introduction part 60 has an opening 603 at the downstream end in the liquid introduction direction in its introduction path 601. In the example shown in FIGS. 8 and 10, the first introduction part 60 is connected to the first storage chamber 62 through an opening 603 that opens at an end opposite to the introduction port 60a from which the liquid is introduced from the liquid container 24 (see FIG. 2) mounted on the mounting part 28. Thus, the first introduction part 60 is connected to the first storage chamber 62 through the opening 603 at the downstream end in the liquid introduction direction from the liquid container 24 in the introduction path 601 passing through its interior. The opening surface of the opening 603 may be inclined with respect to the horizontal plane as shown in FIGS. 8 and 10. Note that the opening surface of the opening 603 may be a horizontal plane.

[0091] The first introduction part 60 may include a regulating part 602 that separates the introduction path 601 from the first storage chamber 62. The regulating part 602 functions as a partition plate that separates the introduction path 601 from the first storage chamber 62. The regulating part 602 has a function of regulating the first liquid level 66, which is the liquid level in the first storage chamber 62, to the standard position SH.

[0092] As shown in FIGS. 8 and 10, the tank unit 26 includes a lead-out part 74 and a second introduction part 75. The lead-out part 74 communicates with the second storage chamber 68 and is configured to be able to lead out the liquid in the second storage chamber 68 toward the liquid discharge head 23 (see FIG. 2). The lead-out part 74 is connected to one end of a supply flow path 37 that communicates with the liquid discharge head 23 (see FIG. 2).

[0093] The second introduction part 75 communicates with the first storage chamber 62 and is configured to be able to introduce the liquid recovered from the liquid discharge head 23. The second introduction part 75 is connected to one end of a recovery flow path 39 that communicates with the liquid discharge head 23.

[0094] As shown in FIG. 8, the tank unit 26 has a first connection portion 76 to which the atmosphere release passage 50 is connected. The atmosphere release passage 50 (see FIG. 2) is constituted by, for example, a tube, and one end of this tube is connected to the first connection portion 76. The first connection portion 76 is constituted by, for example, a pipe portion to which a pipe such as a tube can be connected. The tank unit 26 has an air flow passage 78 that communicates with the first connection portion 76. The air flow passage 78 communicates with the inside of the first storage chamber 62 via the first atmosphere release portion 64 shown in FIG. 10. Specifically, the first storage portion 33 has an atmosphere release port 33a shown in FIG. 10. The first storage chamber 62 communicates with the air flow passage 78 shown in FIG. 8 via the atmosphere release port 33a and the first atmosphere release portion 64.

[0095] The first storage chamber 62 in the tank unit 26 communicates with the atmosphere release passage 50 (see FIG. 2) via the first atmosphere release portion 64, the air flow passage 78, and the first connection portion 76. Therefore, the first gas phase portion 62G in the first storage chamber 62 is open to the atmosphere. As described above, when the first atmosphere release portion 64 includes a gas-liquid separation membrane, the inside of the first storage chamber 62 can be opened to the atmosphere while preventing leakage of the liquid in the first storage chamber 62 to the outside.

[0096] As shown in FIG. 8, the tank unit 26 includes a second connection portion 77 that communicates with the second storage chamber 68. The second connection portion 77 communicates with the second atmosphere release portion 69. The second connection portion 77 is connected to the pressurized flow passage 51. The pressurized flow passage 51 is constituted by, for example, a tube, and one end of this tube is connected to the second connection portion 77. The second connection portion 77 communicates with the second air flow passage 79.

[0097] The second air flow path 79 communicates with the second storage chamber 68 via the second atmosphere release portion 69. The second storage chamber 68 communicates with the pressurization flow path 51 (see FIG. 2) via the second atmosphere release portion 69, the second air flow path 79, and the second connection portion 77. The pressurization in the second storage chamber 68 is performed by introducing pressurized air from the pressurization portion 47 through the pressurization flow path 51, the second connection portion 77, the second air flow path 79, and the second atmosphere release portion 69. Specifically, the second storage portion 35 has an atmosphere release port 35a shown in FIG. 10. The second storage chamber 68 communicates with the air flow path 79 shown in FIG. 8 via the atmosphere release port 35a and the second atmosphere release portion 69.

[0098] When the cleaning time comes, the control unit 19 drives the pressurization portion 47 to introduce pressurized air into the second storage chamber 68, thereby pressurizing the liquid in the second storage chamber 68. As a result, the liquid is forcibly discharged from the nozzles 22 of the liquid discharge head 23. In this way, the cleaning of the liquid discharge head 23 is performed. By the cleaning, clogging of the nozzles 22 of the liquid discharge head 23 is prevented or eliminated.

[0099] When the second atmosphere release portion 69 includes a gas-liquid separation membrane, it is possible to introduce pressurized air into the second storage chamber 68 while preventing leakage of the liquid in the second storage chamber 68 to the outside. Note that pressurized air may be introduced into the first storage chamber 62 from the pressurization portion 47 through the atmosphere release path 50.

[0100] As shown in FIG. 10, the opening 603 may be located below the center HL in the first storage chamber 62 in the vertical direction Z. In FIG. 10, the region where the first storage chamber 62 exists in the vertical direction Z (Z-axis direction) is defined as a storage chamber region TA. The first introduction portion 60 is connected to the first storage chamber 62 at a height in the middle of the storage chamber region TA in the vertical direction Z. An opening 603 is formed at the lower end of the introduction path 601 of the first introduction portion 60. The first introduction portion 60 is connected to the first storage chamber 62 via the opening 603 at a height position in the middle of the storage chamber region TA in the vertical direction Z. A restricting portion 602, which is a part of the member forming the introduction path 601, functions as a partition between the introduction path 601 and the first storage chamber 62.

[0101] The lower end 604 of the regulating portion 602 defines the height of the first liquid level 66 at the standard position SH. That is, the height position of the lower end 604 of the regulating portion 602 is set so that the first liquid level 66 becomes the standard position SH. When liquid is injected from the liquid container 24, when the first liquid level 66 rises and reaches the lower end 604 of the regulating portion 602, the supply of liquid from the liquid container 24 through the first introduction portion 60 stops.

[0102] Inside the first storage chamber 62, with the first liquid level 66 as a boundary, it is partitioned into a first liquid phase portion 62L which is a liquid phase portion where liquid is stored and a first gas phase portion 62G which is a gas phase portion of air. That is, the first storage chamber 62 is partitioned into a first liquid phase portion 62L which is a region below the first liquid level 66 and a first gas phase portion 62G which is a region above the first liquid level 66.

[0103] Inside the second storage chamber 68, with the second liquid level 70 as a boundary, it is partitioned into a second liquid phase portion 68L which is a liquid phase portion where liquid is stored and a second gas phase portion 68G which is a gas phase portion of air. That is, the second storage chamber 68 is partitioned into a second liquid phase portion 68L which is a region below the second liquid level 70 and a second gas phase portion 68G which is a region above the second liquid level 70. Note that in the region including inside the introduction path 601, with a liquid level 67 having substantially the same height as the first liquid level 66 as a boundary, an introduction gas phase portion 60G which is a gas phase portion of air is partitioned above it.

[0104] As shown in FIGS. 8 and 10, the liquid level detection portion 63 includes a first detection portion 63a, a second detection portion 63b, and a third detection portion 63c. The first detection portion 63a shown in FIG. 10 detects the first liquid level 66 when it is at the standard position SH. The control portion 19 determines that the first liquid level 66 is at a normal height when the first liquid level 66 is at the standard position SH. When the first detection portion 63a fails to detect the first liquid level 66 because the first liquid level 66 has deviated from the standard position SH beyond the allowable range, the control portion 19 may adjust the first liquid level 66 to a height where the first detection portion 63a can detect it. For example, the control portion 19 may adjust the first liquid level 66 to the standard position SH by controlling the pressure inside the first storage chamber 62 through the first atmosphere release portion 64 by controlling the pressurizing portion 47 and the switching mechanism 48.

[0105] The second detection unit 63b shown in FIG. 8 detects the first liquid level 66 (see FIG. 10) when the remaining amount of the liquid in the first storage chamber 62 is less than the end threshold value. The second detection unit 63b detects that the remaining amount of the liquid in the first storage chamber 62 has reached the end. When the remaining amount reaches the end, the control unit 19 displays a message or the like prompting the replacement of the liquid container 24 on the display unit 15a.

[0106] The third detection unit 63c shown in FIG. 8 detects the first liquid level 66 (see FIG. 10) when it is at the full level position that excessively exceeds the standard position SH. By detecting the first liquid level 66 at the full level position, the third detection unit 63c prevents liquid leakage from the nozzles 22 of the liquid discharge head 23. Further, the third detection unit 63c detects the first liquid level 66 when approaching the overflow liquid amount, thereby preventing the liquid in the first storage chamber 62 from overflowing from the atmosphere opening 33a. The full level position is set to a liquid level height before reaching the liquid level at which overflow occurs and at which no liquid leakage occurs from the nozzles 22 due to the water head difference between the nozzles 22 of the liquid discharge head 23 and the first liquid level 66.

[0107] As shown in FIGS. 8 and 10, at least a part of the first storage chamber 62 and the second storage chamber 68 are provided so as to overlap in the vertical direction Z. In the example shown in FIGS. 8 and 10, the first storage chamber 62 and the second storage chamber 68 are arranged in a layout in which a portion that horizontally projects at the upper part of the first storage chamber 62 and a portion that horizontally projects at the lower part of the second storage chamber 68 are overlapped in the vertical direction Z.

[0108] The first storage chamber 62 is a storage chamber whose remaining amount is to be detected by the liquid level detection unit 63 for the remaining amount detection target of the tank unit 26. In order to reduce the variation in the end detection accuracy when the remaining amount reaches the end, it is desirable that the rate of change of the liquid level height per unit liquid volume is large when the remaining amount in the first storage chamber 62 decreases. Therefore, the first storage chamber 62 desirably has a shape in which the lower volume is smaller than the upper volume. On the other hand, in order to be able to store the liquid pushed out by the thermal expansion of the gas phase part in the liquid container 24 due to temperature change in the first storage chamber 62, it is desirable that the first storage chamber 62 has a large volume. Therefore, the first storage chamber 62 desirably has a shape in which the upper volume is large instead of the lower volume being small, as shown in FIGS. 8 and 10. In the examples shown in FIGS. 8 and 10, the first storage chamber 62 has a shape in which the upper part projects horizontally compared to the lower part.

[0109] Since the second storage chamber 68 does not need to detect the second liquid level 70, as shown in FIGS. 8 and 10, a shape in which the lower volume is larger than the upper volume is possible. In the examples shown in FIGS. 8 and 10, the second storage chamber 68 has a shape in which the lower part projects horizontally compared to the upper part.

[0110] And, as shown in FIGS. 8 and 10, the first storage part 33 and the second storage part 35 are arranged such that the horizontally projecting part at the upper part of the first storage part 33 and the horizontally projecting part at the lower part of the second storage part 35 overlap in the vertical direction Z. For this reason, the first storage chamber 62 and the second storage chamber 68 are efficiently arranged in a substantially rectangular parallelepiped accommodation space.

[0111] As shown in FIG. 10, the tank unit 26 may be provided between the second storage chamber 68 and the lead-out part 74, and may further include a filter 100 capable of capturing foreign matters contained in the liquid. Here, the foreign matters include bubbles and minute dust contained in the liquid. Note that the filter 100 may also be provided between the first storage chamber 62 and the second introduction part 75. In this case, one common filter 100 may be provided, or they may be provided individually.

[0112] As shown in Fig. 9, the first storage chamber 62 may have a covering portion 88 inside. The covering portion 88 may be provided vertically above the second introduction portion 75 that opens to the lower surface inside the first storage chamber 62. As shown in Fig. 9, a communication port 75a through which the second introduction portion 75 communicates with the first storage chamber 62 is opened on the lower surface (inner bottom surface) of the first storage chamber 62. The covering portion 88 is provided vertically above this communication port 75a. The covering portion 88 has a roof shape that covers the communication port 75a. When the circulated liquid is introduced from the second introduction portion 75, the liquid may gush out vigorously from the communication port 75a into the first storage chamber 62. Even in such a case, when the gushed liquid hits the covering portion 88, the momentum of the liquid is suppressed. Therefore, it is suppressed that the liquid flowing in from the communication port 75a blows up to near the atmosphere release port 33a.

[0113] As shown in Fig. 10, the on-off valve 36 includes a one-way valve that allows the flow of liquid from the first storage chamber 62 to the second storage chamber 68 and restricts the flow in the direction from the second storage chamber 68 to the first storage chamber 62. In the example shown in Fig. 10, a plurality (for example, two) of on-off valves 36 are provided. The detailed configuration of the one-way valve constituting the on-off valve 36 will be described later.

[0114] As shown in Fig. 10, the atmosphere release portion 64 has a gas-liquid separation membrane. The gas-liquid separation membrane is, for example, a moisture permeable membrane. The gas-liquid separation membrane allows air to pass through but does not allow liquid to pass through. The moisture permeable membrane is set with water repellency on its surface assuming water. The moisture permeable membrane has lower water repellency and is more likely to penetrate when the liquid is ink than when it is water. Therefore, a former made of a water repellent or an antifoaming agent may be applied to the moisture permeable membrane to make it difficult for ink to penetrate.

[0115] <Liquid container 24> As shown in FIG. 10, a gas phase portion 62G is required in the first storage chamber 62. Since the inside of the liquid container 24 is a sealed space, when the air inside expands due to a temperature change, the liquid may be pushed out from the liquid container 24 into the first storage chamber 62. Therefore, even if the maximum amount of liquid assumed to be pushed out from the liquid container 24 due to the expansion of the air inside the liquid container 24, the gas phase portion 62G is set to a volume that can accommodate the pushed-out amount of liquid in the first storage chamber 62.

[0116] As shown in FIG. 1, the volume of the liquid container 24 varies depending on the type of liquid (e.g., ink color). The liquid container 24 is wider for black than for those with a color ink. Since the first storage portion 33 corresponding to black is wide like the liquid container 24, the gas phase portion 62G of the first storage chamber 62 shown in FIG. 10 is larger for black than for those with a color. If the liquid usage ratio (supply ratio) of the liquid container 24 is the same, the gas phase portion of the black one is larger than that of the color one, and the amount of liquid (e.g., ink) pushed out when the air in the gas phase portion thermally expands is also larger for black. In this example, the gas phase portion 62G of the first storage chamber 62 is larger for black than for color. Therefore, even if the liquid is pushed out from the liquid container 24 due to the thermal expansion of the air inside the liquid container 24 caused by a temperature change, the pushed-out liquid can be accommodated in the first storage chamber 62 without overflowing.

[0117] As shown in FIG. 10, the first introduction portion 60 is inclined at a predetermined angle. The predetermined angle is a predetermined value within the range of, for example, 1 to 15 degrees. For this reason, the liquid container 24 is mounted inclined by a predetermined angle with respect to the vertical direction Z, similar to the angle of the first introduction portion 60. By mounting the liquid container 24 in an inclined posture by a predetermined angle, the remaining amount of the liquid container 24 can be used up almost until the end.

[0118] <Detection of the inclination of the tank unit 26> As shown in FIG. 12, the tank unit 26 further includes an inclination detection unit 98 that detects the inclination of the tank unit 26 itself. That is, the inclination detection unit 98 is supported in a fixed state with respect to the frame 89 that supports the tank unit 26. The inclination detection unit 98 outputs a detection signal obtained by detecting the inclination of the tank unit 26 to the control unit 19.

[0119] The control unit 19 determines whether or not the inclination angle of the tank unit 26 exceeds an angle threshold value based on the detection signal from the inclination detection unit 98. When the inclination angle of the tank unit 26 exceeds the angle threshold value, the control unit 19 prohibits the printing operation (liquid ejection operation) by the liquid ejection device 11. Further, the control unit 19 causes the display unit 15a to display a message or the like prompting the user to adjust the inclination of the liquid ejection device 11. One of the causes of excessive inflow of the liquid from the liquid storage body 24 to the first storage unit 33 is an inclination of the tank unit 26 that exceeds the allowable range. Therefore, when the inclination angle of the tank unit 26 detected by the inclination detection unit 98 exceeds a predetermined angle threshold value, the control unit 19 may cause the display unit 15a to display a message or the like prompting the user to adjust the inclination of the posture of the liquid ejection device 11. Further, when the inclination angle of the tank unit 26 detected by the inclination detection unit 98 exceeds a predetermined angle threshold value, the control unit 19 may keep the liquid ejection device 11 in a state where printing cannot be started until this excessive inclination is eliminated. In this case, when the detection angle of the inclination detection unit 98 becomes equal to or less than the angle threshold value as a result of the user adjusting the inclination of the liquid ejection device 11, the control unit 19 starts the printing operation of the liquid ejection device 11 based on a printing instruction from the user.

[0120] As shown in FIGS. 11 and 12, in the tank unit 26, a plurality of sets of first introduction portions 60 and positioning protrusions 248 are arranged in a row along the X axis. A plurality of liquid level detection portions 63 are arranged in a row along the X axis at positions adjacent to the plurality of first introduction portions 60 on the side opposite to the positioning protrusion 248 in the direction along the Y axis. The plurality of liquid level detection portions 63 are in a state where their respective terminal portions 63d are exposed from the upper surface of the mounting portion 28. The terminal portion 63d is electrically connected to the control unit 19 via a signal line (not shown).

[0121] The tank unit 26 includes absorption members 93 and 94 disposed below the first storage portion 33. The absorption members 93 and 94 have a function of absorbing liquids such as ink that leak when the liquid container 24 is attached and detached. The absorption members 93 and 94 are arranged over a range capable of absorbing the liquid scattered or dripping from the first introduction portion 60. Here, when the liquid container 24 is removed from the mounting portion 28, the liquid scattered from the first introduction portion 60 and the liquid dripping along the side surface of the first introduction portion 60 are guided to the first absorption member 93.

[0122] The first absorption member 93 is supported by the frame 89 in a state of standing vertically along the vertical direction Z at a position near directly below the first introduction portion 60. The second absorption member 94 is horizontally placed on the frame 89 in a state where a part thereof is in contact with the base end portion of the first absorption member 93. As shown in FIG. 11, the two absorption members 93 and 94 have a substantially L-shaped configuration in side view. The second absorption member 94 is arranged over substantially the entire area of the region directly below the first storage portion 33 and the second storage chamber 68. For this reason, the liquid that may leak from the first storage portion 33 and the second storage chamber 68 and the liquid dripping along the outer wall surfaces thereof are absorbed by the second absorption member 94.

[0123] <Liquid leakage suppression structure from the first introduction portion 60> Next, with reference to FIGS. 13 and 14, a liquid leakage suppression structure that suppresses the leakage of liquid from the inlet 60a of the first introduction portion 60 and recovers the leaked liquid will be described. The tank unit 26 includes a liquid leakage suppression structure in the vicinity and below the first introduction portion 60.

[0124] As shown in FIG. 13, this liquid leakage suppression structure is composed of a liquid scattering prevention wall 605 provided on the first introduction portion 60 and a liquid recovery structure including a guiding groove 606 capable of recovering the scattered liquid.

[0125] First, referring to FIGS. 6, 7, and 14, the phenomenon of liquid splashing from the inlet 60a when the liquid container 24 is removed will be described. In the space 60s, which is a part of the flow path in the first introduction portion 60, a part of the liquid introduced from the pouring portion 30 into the first introduction portion 60 remains. In the process of removing the liquid container 24 from the mounting portion 28, the space 60s in the first introduction portion 60 becomes negative pressure due to volume expansion. Specifically, with the inlet 60a blocked by the protrusion 31c, the valve body 61a rises toward the inlet 60a. The rise of the valve body 61a closes the introduction valve 61. Even though the introduction valve 61 is closed, the inlet 60a is still blocked by the protrusion 31c (see FIG. 7). Therefore, the space 60s (see FIG. 14) in the first introduction portion 60 temporarily becomes a closed space. After the formation of this closed space 60s, in the process until the protrusion 31c is further displaced upward and removed from the inlet 60a, the closed space 60s is depressurized by the expansion of the internal air and becomes negative pressure. This negative pressure acts as a force to suck up the liquid remaining in the space 60s toward the inlet 60a side. Therefore, when the liquid container 24 is removed from the mounting portion 28, there is a possibility that the liquid will splash from the inlet 60a.

[0126] The first introduction portion 60 has a liquid splash prevention wall 605 attached to the tip portion on the inlet 60a side in a state of covering only the inlet 60a and its periphery. The liquid splash prevention wall 605 has an annular wall portion covering the peripheral edge of the inlet 60a.

[0127] As shown in FIG. 13, a liquid splash prevention wall 605 is attached to the tip portion of the first introduction portion 60 so as to surround the periphery with the inlet 60a left open. The liquid splash prevention wall 605 can considerably suppress the splashing of the liquid from the inlet 60a. However, it cannot completely prevent the splashing of the liquid from the inlet 60a.

[0128] Therefore, the tank unit 26 has a liquid recovery structure for recovering the liquid splashed from the inlet 60a. The liquid recovery structure includes the annular guide groove 606 shown in FIG. 13, the guide recess 96, the guide hole 96a shown in FIG. 14, the guide portion 97, and the first absorption member 93.

[0129] The liquid recovery structure has a guiding groove 606 in an area capable of receiving the liquid scattered from the inlet 60a and falling around it. The first introduction part 60 has a tubular protruding part 607 with the inlet 60a opening at the tip. The guiding groove 606 is formed as an annular groove path on the upper surface of the frustum-shaped part arranged at the base of the protruding part 607.

[0130] In a side view seen from the direction along the X-axis shown in FIG. 14, the formation surface of the guiding groove 606 is inclined at a predetermined angle with respect to the horizontal plane. The predetermined angle is, for example, substantially equal to the angle at which the axis CL of the first introduction part 60 is inclined with respect to the vertical direction Z. The annular guiding groove 606 guides the liquid in the lower direction.

[0131] As shown in FIG. 14, between the first introduction part 60 and the positioning protrusion 248, a concave guiding recess 96 is formed that guides the liquid downward along the side surface from the lower groove end of the guiding groove 606. As shown in FIG. 13, the guiding recess 96 is formed by a space partitioned by three wall plate parts 96b arranged at intervals along the X-axis between the first introduction part 60 and the positioning protrusion 248. The guiding groove 606 opens toward the guiding recess 96 at the lower end so as to be able to guide the liquid into the guiding recess 96. The liquid guided along the annular guiding groove 606 after scattering from the inlet 60a is guided into the guiding recess 96. As shown in FIG. 14, the liquid guided to the lower side along the annular guiding groove 606 is guided downward through the guiding recess 96.

[0132] As shown in Fig. 14, a guiding hole 96a is open at the bottom of the guiding recess 96. The liquid passing through the guiding hole 96a either travels along the side wall or drips down. Near the lower end of the guiding path of the liquid that travels along this side surface or drips down, the first absorbing member 93 is arranged. Near the lower end of the guiding path of the liquid, a guide portion 97 that bites into the upper part of the first absorbing member 93 is arranged in an inclined posture. The liquid guided downward along the guiding path of the liquid is guided by the guide portion 97 to the first absorbing member 93 and absorbed by the first absorbing member 93. The first absorbing member 93 is located inside the frame 89. Therefore, the liquid absorbed by the first absorbing member 93 does not leak outside the frame 89.

[0133] <Configuration of the on-off valve 36> Next, with reference to Figs. 15 to 18, the configuration of the on-off valve 36 will be described. The on-off valve 36 is a differential pressure valve that opens and closes due to the head difference between the first liquid level 66 in the first storage chamber 62 and the second liquid level 70 in the second storage chamber 68. The on-off valve 36 includes a valve body 101.

[0134] For example, as a valve body constituting a differential pressure valve that opens and closes with this type of head difference, conventionally, an umbrella valve, which is an umbrella-shaped valve body, may be used. However, it is difficult for the umbrella valve to ensure the necessary contact pressure against the valve seat, and there is a possibility of minute leakage of the liquid. This type of minute leakage causes variations in the height of the second liquid level 70. This means variations in the head difference, which affects the size of the liquid droplets ejected from the liquid ejection head 23 and, ultimately, the printing quality. Therefore, it is desired that this type of minute leakage be suppressed to the smallest possible amount or reduced to zero. Thus, in this embodiment, as the valve body of the on-off valve 36, a valve body 101 having the shape shown in Figs. 16 and 17 is adopted. Note that one surface (bottom surface) of the lead-out flow path 34 is formed by the film F3 shown in Fig. 17.

[0135] As shown in FIGS. 16 and 17, the valve body 101 includes a shaft portion 102 and a valve portion 103. The shaft portion 102 has a stop portion 104 that bulges in the radial direction more than other portions at a middle portion in its axial direction. Further, the shaft portion 102 extends substantially perpendicularly from the central portion of the disc-shaped valve portion 103.

[0136] The valve portion 103 includes a valve plate portion 103a having a disc shape with a predetermined thickness to enhance rigidity, a lip portion 105 formed of an annular linear seal protruding from the surface of the valve plate portion 103a on the side of the shaft portion 102, and an annular fin portion 106 extending radially outward from the peripheral edge of the valve plate portion 103a. The fin portion 106 is thinner and more flexible than the valve plate portion 103a. The fin portion 106 may be thinner toward the outside.

[0137] As shown in FIG. 17, a plurality of valve holes 332 are formed in a portion of the partition wall portion 331 between the first storage chamber 62 and the outlet flow path 34 where the valve body 101 is assembled. The plurality of valve holes 332 communicate the first storage chamber 62 and the outlet flow path 34. The surface of the partition wall portion 331 facing the outlet flow path 34 in the portion where the plurality of valve holes 332 are formed is formed as a concave surface, and the bottom surface of the concave surface serves as a valve seat 333. FIG. 17 shows the valve body 101 in an open valve state where its valve portion 103 is separated from the valve seat 333. The valve body 101 moves in its axial direction and opens and closes the valve hole 332 by the differential pressure between the hydraulic pressure of the water head determined by the height of the first liquid level 66 of the liquid in the first storage chamber 62 and the hydraulic pressure of the water head determined by the height of the second liquid level 70 of the liquid in the second storage chamber 68, the weight of the valve body 101, and the buoyancy acting on the valve body 101 in the liquid. That is, as shown in FIG. 17, the valve body 101 moves between an open valve position where the valve portion 103 is separated from the valve seat 333 and a closed valve position where the valve portion 103 abuts against the valve seat 333 with a predetermined pressing force. Note that the open valve position of the valve body 101 shown in FIG. 17 is an example, and a position where the lip portion 105 and the fin portion 106 of the valve portion 103 are separated from the valve seat 333 by at least a little and there is a flow of liquid through the valve hole 332 is the open valve position.

[0138] In the case of a conventional umbrella valve, for example, the valve portion of the entire valve portion was in a fin shape where the thickness gradually became thinner toward the outer peripheral side in the radial direction. For this reason, the valve portion of the umbrella valve had a relatively large area of a highly flexible portion. Therefore, the valve portion of the umbrella valve was easily bent due to its high flexibility, and the pressing force against the valve seat when the valve portion contacted the valve seat was relatively low. Due to this, the umbrella valve was a valve configured such that minute leakage was likely to occur in the closed valve position.

[0139] On the other hand, in the valve body 101 of the embodiment, the valve plate portion 103a is in the shape of a disk with a substantially constant thickness and has relatively high rigidity. Moreover, on the surface of the valve plate portion 103a facing the valve seat 333, there is a lip portion 105 formed of a line seal protruding in an annular shape. Further, the valve portion 103 has an annular fin portion 106 extending radially outward from the peripheral edge of the valve plate portion 103a. Thus, the valve body 101 has an annular lip portion 105 and an annular fin portion 106 located on the outer peripheral side thereof surrounding the lip portion 105. When the on-off valve 36 is closed, the lip portion 105 is pressed against the valve seat 333 and sealed by the line seal. Moreover, on the outer peripheral side of the line seal, the fin portion 106 is pressed against the surface of the valve seat 333 in a slightly bent state. For this reason, when the on-off valve 36 is closed and the valve body 101 contacts the surface of the valve seat 333, the pressing force required is obtained.

[0140] Also, as shown in FIG. 17, since the on-off valve 36 has a plurality of valve holes 332 with a relatively small flow path cross-sectional area, the pressure loss is large due to the relatively large flow resistance during valve opening. Therefore, in order to reduce the pressure loss, as in the example shown in FIG. 17, two on-off valves 36 may be provided in parallel. With the two on-off valves 36, the total flow path cross-sectional area of the valve holes 332 becomes large, and the pressure loss can be suppressed to be small.

[0141] The on-off valve 36 is a differential pressure valve having a float-type valve body 101 that opens and closes due to the head difference caused by the difference in the liquid levels between the first storage chamber 62 and the second storage chamber 68. Here, the float-type valve body 101 is a differential pressure valve in which the valve body 101 in a floating state in the liquid moves due to the differential pressure caused by the head difference between the first storage chamber 62 and the second storage chamber 68, without using a biasing member such as a spring that biases the valve body 101 in the valve closing direction to open and close. In this way, since the on-off valve 36 is of the float type that opens with a small head difference, it opens immediately if there is a slight difference in height between the first liquid level 66 and the second liquid level 70. Therefore, the second liquid level 70 can be adjusted to the same height as the first liquid level 66, and it is difficult for a height difference to occur between the first liquid level 66 and the second liquid level 70.

[0142] FIG. 18 is a graph comparing the pressing forces on the valve seat 333 at the time of valve closing for each of the valve body of a conventional umbrella valve and the valve body 101 of the embodiment. In this graph, the horizontal axis represents the reservoir pressing force (kPa) received by the valve body from the liquid in the second storage chamber 68, and the vertical axis represents the seal pressure (kPa) when the valve body abuts against the valve seat 333. The line L1 shown by the solid line in FIG. 18 indicates the seal pressure with respect to the reservoir pressing force of the valve body 101 of the embodiment, and the line L2 shown by the one-dot chain line in the same figure indicates the seal pressure with respect to the reservoir pressing force of the valve body constituting the conventional umbrella valve. As can be seen from the graph of FIG. 18, the seal pressure with respect to the reservoir pressing force is approximately twice as high when the valve body 101 of the embodiment is used as compared with when the valve body of the conventional umbrella valve is used. This indicates that by configuring the valve body 101 to have a lip portion 105 formed of an annular linear seal and an annular fin portion 106, the seal pressure becomes approximately twice as high. The reservoir pressing force in the use area of the liquid discharge device 11 is, for example, about 5 to 70 (kPa). For example, the reservoir pressing force increases step by step in the order of printing, liquid circulation, and cleaning. Even during printing when the reservoir pressing force is relatively small, the necessary seal pressure can be surely ensured. Note that the reservoir pressing force in the use area may be changed as appropriate.

[0143] <Reverse mounting of the liquid container 24> Next, with reference to FIGS. 19 to 23, problems that occur when a user attempts to attach the liquid container 24 incorrectly front to back and the structure of the attachment portion 28 that solves these problems will be described. Note that FIG. 19 shows a state in which the user attaches the liquid container 24 in the correct orientation in the present embodiment. FIGS. 20 to 22 show the configuration of the conventional attachment portion 28 and explain the problems that occur when the user attempts to attach the liquid container 24 incorrectly front to back. FIG. 23 shows the structure of the attachment portion 28 of the embodiment.

[0144] As shown in FIG. 19, when the orientation of attaching the liquid container 24 is correct, the liquid container 24 is inserted straight horizontally into the box-shaped frame 80 through the insertion port 28o. The liquid container 24 is inserted straight along the top plate 81 that constitutes the frame 80. During the insertion process of the liquid container 24, the guide portion 247 on the attachment portion 28 side is engaged with the receiving portion 447 on the liquid container 24 side. Specifically, as the insertion of the liquid container 24 into the frame progresses, first, the two guide portions 247a are sequentially engaged with the first receiving portion 447a, and further, at the final stage of completing the attachment, the guide portion 247b is engaged with the second receiving portion 447b. The liquid container 24 is provided with a stopper 449 that restricts further insertion of the liquid container 24 into the frame 80 at the rear end face of the first receiving portion 447a.

[0145] Next, with reference to FIGS. 20 to 23, the problems that occur when the user inserts the liquid container 24 incorrectly front to back will be described. As shown in FIG. 20, conventionally, even when the user attempts to insert the liquid container 24 incorrectly front to back into the frame 80 of the attachment portion 28, the guide portion 247a hits the stopper 449 formed of a rib located at the rear end of the receiving portion 447a. For this reason, the configuration is such that the liquid container 24 cannot be inserted further in the reverse front-to-back direction.

[0146] However, the user may forcefully push the liquid container 24. In this case, if the user pushes while tilting the liquid container 24, as shown in FIG. 21, the rear end portion of the liquid container 24 passes above the guide portion 247a and pushes upward the portion near the insertion port 28o of the top plate 81. In this case, the upper surface of the rear end portion of the liquid container 24 deflects the top plate 81 upward near the insertion port 28o, and the liquid container 24 is inserted from the insertion port 28o to a predetermined position, so that the liquid container 24 may be in a state where it cannot be removed. Further, if the liquid container 24 is deeply inserted into the frame 80 beyond the stopper 449 in the guide portion 247a, as shown in FIG. 22, the guide portion 247a may be engaged with the receiving portion 447a. In this case, once the guide portion 247a engaged with the receiving portion 447a hits the stopper 449, the liquid container 24 cannot be removed from the frame 80 and enters the deadlock state shown in FIG. 22.

[0147] To avoid such a deadlock state, as shown in FIGS. 19 and 23, the mounting portion 28 of the embodiment has a protrusion 110 on the lower surface near the insertion port 28o of the top plate 81 constituting the frame 80. Even if the top plate 81 deflects when the rear end portion of the liquid container 24 is forcibly inserted from the insertion port 28o downward (in the vertical direction Z) from the lower surface of the top plate 81, the upper surface of the rear end portion of the liquid container 24 hits the protrusion 110 and cannot be inserted further into the frame 80. Therefore, the liquid container 24 is prevented from entering the deadlock state.

[0148] <Operation of the Embodiment> Next, the operation of this embodiment will be described. The user attaches the liquid container 24 to the attachment portion 28 of the tank unit 26. Thereby, the pouring portion 30 of the liquid container 24 and the first introduction portion 60 of the tank unit 26 are connected. Such attachment of the liquid container 24 is performed, for example, when replacing the liquid container 24 when the liquid in the previous liquid container 24 runs out. For example, when it is detected that the liquid in the tank unit 26 has ended, or when the state where the first liquid level 66 in the first storage chamber 62 is located below the standard position SH continues for a period exceeding a certain period. In this case, the control unit 19 causes the display unit 15a to display a message prompting the replacement of the liquid container 24. The user who sees this message replaces the liquid container 24.

[0149] By the way, the first introduction portion 60 communicates with the first storage chamber 62 through an opening 603 located at a middle height in the vertical direction Z of the first storage chamber 62. While the first gas phase portion 62G and the introduced gas phase portion 60G communicate with each other through the opening 603, liquid is supplied from the liquid container 24 to the first storage chamber 62. And when the first liquid level 66 in the first storage chamber 62 reaches the standard position SH (see FIG. 10), which is a middle height in the vertical direction Z of the first storage chamber 62, the first gas phase portion 62G and the introduced gas phase portion 60G no longer communicate. In other words, when the first liquid level 66 reaches the lower end 604 of the regulating portion 602 and the first gas phase portion 62G and the introduced gas phase portion 60G no longer communicate. That is, the air flow path from the first gas phase portion 62G to the introduced gas phase portion 60G is cut off. As a result, the supply of liquid from the liquid container 24 to the first storage chamber 62 stops.

[0150] Also, when liquid is supplied from the second storage chamber 68 to the liquid discharge head 23 and the second liquid level 70 becomes lower than the first liquid level 66, the on-off valve 36 opens due to the head difference between the first storage chamber 62 and the second storage chamber 68. As a result, liquid flows from the first storage chamber 62 to the second storage chamber 68 through the lead-out flow path 34. Thereby, when the first liquid level 66 drops below the standard position SH, the first gas phase portion 62G and the introduced gas phase portion 60G communicate with each other again to form an air flow path, and the supply of liquid from the liquid container 24 to the first storage chamber 62 is started.

[0151] When liquid is supplied from the liquid container 24 to the first storage chamber 62 and the liquid level in the first storage chamber rises, the liquid level 66 in the first storage chamber becomes higher than the liquid level 70 in the second storage chamber. Further, when the liquid in the second storage chamber 68 is supplied to the liquid ejection head 23 for liquid circulation, printing (liquid ejection process), or cleaning, the liquid level 70 in the second storage chamber drops, and the liquid level 70 in the second storage chamber becomes lower than the liquid level 66 in the first storage chamber.

[0152] In these cases, when the on-off valve 36 opens, the heights of the liquid level 66 in the first storage chamber and the liquid level 70 in the second storage chamber are adjusted to be the same. When the liquid levels 66 in the first storage chamber and 70 in the second storage chamber become almost the same height and the head difference disappears, the on-off valve 36 closes. In this way, the liquid levels 66 in the first storage chamber and 70 in the second storage chamber are adjusted to a standard position SH at almost the same height (see FIGS. 2 and 10).

[0153] In this way, the liquid level 66 in the first storage chamber 62 is automatically adjusted to the standard position SH, which is the position where the first introduction part 60 is connected to the first storage chamber 62 at the opening 603 at the lower end of its introduction path 601 and is at the middle height in the vertical direction Z of the first storage chamber 62. That is, the liquid level 66 is automatically adjusted to the standard position SH, which is the height of the lower end 604 of the restricting part 602, which is the partition wall between the introduction path 601 and the first storage chamber 62.

[0154] At this time, as shown in FIGS. 16 and 17, the valve body 101 of the on-off valve 36 has an annular lip part 105 and an annular fin part 106 provided on the thick valve plate part 103a. Therefore, compared with a known umbrella valve, the valve body 101 of the on-off valve 36 can obtain a sealing pressure about twice as much when the reservoir pressurizing force in the second storage chamber 68 is the same (see FIG. 18). For this reason, minute leakage in the on-off valve 36 can be suppressed.

[0155] For example, if the first liquid level 66 exceeds the full position due to the inclination of the liquid ejection device 11 or other reasons, there is a risk of liquid leakage from the nozzle 22 of the liquid ejection head 23 due to the relationship of the water head difference. However, in the present embodiment, when the full position is detected by the liquid level detection unit 63 or an inclination exceeding the angle threshold of the tank unit 26 is detected by the inclination detection unit 98, the control unit 19 prohibits the start of printing of the liquid ejection device 11. Then, a message prompting the user to eliminate the inclination of the liquid ejection device 11 is displayed on the display unit 15a by the control unit 19. The user eliminates the inclination of the liquid ejection device 11. Then, when the detection result of the inclination detection unit 98 is below the angle threshold, the control unit 19 starts printing.

[0156] When the liquid ejection device 11 is in a standby state where printing is not performed, the liquid is circulated. The liquid circulates through a path that returns from the second storage chamber 68 of the tank unit 26, the supply flow path 37, the liquid ejection head 23, and the recovery flow path 39 to the first storage chamber 62 of the tank unit 26. At this time, the supply valve 38 and the circulation valve 40 are opened. Further, the second storage chamber 68 is pressurized while the first storage chamber 62 is open to the atmosphere via the atmosphere opening portion 64.

[0157] As shown in FIG. 10, in the tank unit 26, the liquid supplied from the second storage chamber 68 through the lead-out portion 74 and the supply flow path 37 in the OUT direction indicated by the solid arrow in FIG. 10 returns from the liquid ejection head 23 through the recovery flow path 39 and enters the first storage chamber 62 from the second introduction portion 75. At this time, the pressure in the second storage chamber 68 becomes higher than the pressure in the first storage chamber 62. Therefore, the on-off valve 36 closes. That is, the liquid ejection device 11 closes the lead-out flow path 34 by closing the on-off valve 36 by pressurizing the inside of the second storage chamber 68.

[0158] During this liquid circulation, the liquid that returns from the liquid ejection head 23 to the first storage chamber 62 of the tank unit 26 flows into the first storage chamber 62 through the communication port 75a. At this time, the liquid may spout from the communication port 75a into the first storage chamber 62. However, in this embodiment, a shield-shaped covering portion 88 is provided at a position facing the communication port 75a in the first storage chamber 62. For this reason, the liquid that spouts vigorously from the communication port 75a hits the covering portion 88 and its momentum is suppressed. As a result, it is suppressed that the liquid spouted from the communication port 75a reaches an area where the liquid should not flow in, such as the atmosphere opening 33a.

[0159] Also, the circulating liquid passes through the filter 100 in the process of being supplied from the second storage chamber 68 toward the liquid ejection head 23. Foreign substances including bubbles and minute dust in the circulating liquid are captured by the filter 100. For this reason, at the time of printing of the liquid ejection device 11, the liquid from which foreign substances such as bubbles have been removed is supplied to the liquid ejection head 23.

[0160] At the time of printing, at least one of the supply valve 38 and the circulation valve 40 is opened. The number of valves to be opened among the supply valve 38 and the circulation valve 40 may be determined according to the amount of the liquid ejected from the nozzles 22 of the liquid ejection head 23. For example, the control unit 19 may open only the supply valve 38 if the ejection amount is equal to or less than a predetermined value based on the print data. For example, if the ejection amount exceeds a predetermined value based on the print data, the control unit 19 may open both the supply valve 38 and the circulation valve 40.

[0161] Also, at the time of this printing, the switching mechanism 48 opens the sixth selection valve 73f and the tenth selection valve 73j, so that the inside of the first storage chamber 62 communicates with the atmosphere through the atmosphere release passage 50 and the connection passage 52. Further, the switching mechanism 48 opens the seventh selection valve 73g and the eleventh selection valve 73k, so that the inside of the second storage chamber 68 communicates with the atmosphere through the pressure application passage 51 and the connection passage 52.

[0162] During this printing process, the liquid in the liquid ejection head 23 is under the action of negative pressure based on the head difference between the second liquid level 70 in the second storage chamber 68 and the nozzle 22, and the head difference between the first liquid level 66 in the first storage chamber 62 and the nozzle 22. During printing, the liquid in the second storage chamber 68 is supplied to the liquid ejection head 23 through the supply channel 37, and the liquid in the first storage chamber 62 is supplied to the liquid ejection head 23 through the recovery channel 39 in the OUT direction indicated by the dashed arrow in FIG. 10.

[0163] In addition, the liquid ejection device 11 performs pressurized cleaning of the liquid ejection head 23 regularly or irregularly. The pressurized cleaning pressurizes the liquid in the liquid ejection head 23 by pressurizing the liquid in the second storage chamber 68, and forcibly discharges the liquid from the nozzle 22. At this time, with the supply valve 38 opened and the circulation valve 40 closed, the second storage chamber 68 is pressurized. By driving the pressurizing unit 47 forward, air passing through the connection channel 52 and the pressurizing channel 51 is introduced into the second storage chamber 68 through the atmosphere release portion 69. As a result, the inside of the second storage chamber 68 is pressurized.

[0164] With the circulation valve 40 closed, when the liquid in the second storage chamber 68 is pressurized, the liquid in the liquid ejection head 23 is pressurized. Thereby, pressurized cleaning is performed in which the liquid is forcibly discharged from the nozzle 22 of the liquid ejection head 23. At this time, the on-off valve 36 closes due to the pressurizing force of the second storage chamber 68. The liquid discharged from the nozzle 22 during this pressurized cleaning is discharged into a cap or a flushing box (not shown). Then, the liquid is recovered from the cap or the flushing box to a waste liquid recovery portion (not shown).

[0165] <Effects of the Embodiment> The effects of this embodiment will be described. (1) The tank unit 26 is configured to be able to introduce the liquid supplied from the liquid container 24 and to be able to lead out the liquid toward the liquid discharge head 23 that can discharge the liquid. The tank unit 26 includes a first introduction part 60 for introducing the liquid supplied from the liquid container 24, a first storage chamber 62 for storing the liquid introduced from the first introduction part 60, and a first air release part 64 that can open the inside of the first storage chamber 62 to the atmosphere. Further, the tank unit 26 includes a lead-out flow path 34 having one end connected to the first storage chamber 62 to lead out the liquid in the first storage chamber 62, a second storage chamber 68 connected to the other end of the lead-out flow path 34 for storing the liquid supplied from the first storage chamber 62, and a second air release part 69 that can open the inside of the second storage chamber 68 to the atmosphere. Furthermore, the tank unit 26 includes an opening / closing valve 36 that can open and close the lead-out flow path 34. The first introduction part 60 is connected to the first storage chamber 62 through an opening 603 at an intermediate position in the vertical direction Z of the first storage chamber 62. According to this configuration, without performing supply control or the like, the liquid levels of the two storage chambers 62 and 68 can be set to appropriate heights.

[0166] (2) In the tank unit 26, the opening 603 is located below the center in the first storage chamber 62 in the vertical direction Z. According to this configuration, when there is liquid movement between the first storage chamber 62, the second storage chamber 68, and the liquid container 24 due to environmental changes or the like, it is possible to suppress the liquid from overflowing from the storage chamber or the like.

[0167] (3) The tank unit 26 further includes a liquid level detection part 63 that can detect the liquid level of the liquid in the first storage chamber 62. According to this configuration, it is possible to detect that the liquid in the liquid container 24 has decreased and to suppress the liquid in the first storage chamber 62 from overflowing.

[0168] (4) In the tank unit 26, the opening / closing valve 36 includes a one-way valve that allows the flow of the liquid from the first storage chamber 62 toward the second storage chamber 68 and restricts the flow in the direction from the second storage chamber 68 toward the first storage chamber 62. According to this configuration, a valve drive source is not required.

[0169] (5) In the tank unit 26, the first storage chamber 62 and the second storage chamber 68 are provided such that at least a part of them overlaps in the vertical direction Z. According to this configuration, an efficient layout of the first storage chamber 62 and the second storage chamber 68 is possible.

[0170] (6) The tank unit 26 further includes a lead-out portion 74 that communicates with the second storage chamber 68 and can lead out the liquid in the second storage chamber 68 toward the liquid discharge head 23, and a second introduction portion 75 that communicates with the first storage chamber 62 and can introduce the liquid recovered from the liquid discharge head 23. According to this configuration, the liquid levels of the first storage chamber 62 and the second storage chamber 68 can be maintained at the same liquid level height.

[0171] (7) The tank unit 26 further includes a filter 100 provided between the second storage chamber 68 and the lead-out portion 74 and capable of capturing foreign substances contained in the liquid. According to this configuration, it is possible to capture foreign substances mixed in by replacing the liquid container 24, foreign substances due to circulation, and the like.

[0172] (8) In the tank unit 26, the first storage chamber 62 has a covering portion 88 inside, and the covering portion 88 is provided vertically above the second introduction portion 75 that opens on the lower surface inside the first storage chamber 62. According to this configuration, it is possible to suppress the ink recovered in the first storage chamber 62 from splashing throughout the first storage chamber 62.

[0173] (9) The liquid discharge device 11 includes a liquid discharge head 23 capable of discharging liquid, a tank unit 26, a supply flow path 37 that communicates the lead-out portion 74 and the liquid discharge head 23, and a recovery flow path 39 that communicates the liquid discharge head 23 and the second introduction portion 75. According to this configuration, the liquid discharge device 11 can also obtain the same effects as the tank unit 26.

[0174] (10) The liquid discharge device 11 further includes an inclination detection portion 98 that detects the inclination of the tank unit 26. According to this configuration, since the change amount of the liquid level due to the inclination can be suppressed to be small, the variation in liquid level detection can be reduced.

[0175] (11) The liquid ejection device 11 further includes a pressurizing unit 47 that communicates with the second atmosphere release unit 69 and can pressurize the inside of the second storage chamber 68. According to this configuration, pressurized cleaning becomes possible. This embodiment can be implemented with the following modifications. This embodiment and the following modification examples can be implemented in combination with each other within a technically non - conflicting range.

[0176] · The first introduction unit 60 may be configured to have a pipeline such as a pipe, a hose, or a tube that extends into the first storage chamber 62 having a direction component in the vertical direction Z. · The opening 603 may have a horizontal opening surface. Also, the opening surface of the opening 603 may be inclined in a direction opposite to the inclination direction shown in FIG. 10. Further, the angle formed by the opening surface of the opening 603 with respect to the horizontal plane can be arbitrarily changed. It is only necessary that the opening 603 faces downward. That is, the normal line of the opening surface of the opening 603 may face the vertical direction Z or a direction between the vertical direction Z and the horizontal direction.

[0177] · The first introduction unit 60 may be configured to extend in the vertical direction Z without inclination. · The introduction path 601 of the first introduction unit 60 may be a curved flow path. It is only necessary that the first introduction unit 60 is connected through the opening 603 at an intermediate position in the vertical direction Z of the first storage chamber 62. If this configuration is established, the flow path shape of the introduction path 601 from the introduction port 60a of the first introduction unit 60 to the opening 603 can be any shape. That is, the lower end of the restricting unit 602 serving as a partition between the first storage chamber 62 and the introduction path 601 only needs to be at an intermediate position in the vertical direction Z of the first storage chamber 62. The opening surface of the opening 603 may be inclined obliquely with respect to the horizontal plane when viewed from the direction along the Y - axis. In this case, the height of the first liquid level 66 is defined by the portion that is highest when viewed from the direction along the Y - axis of the opening surface of the opening 603.

[0178] · The on - off valve 36 may be controlled by the control unit 19. The on - off valve 36 may be, for example, an electromagnetic valve. Also, the on - off valve 36 may be a flow rate adjustment valve capable of adjusting the flow rate when the valve is opened.

[0179] · The pressurizing section 47 is not limited to a tube pump, and other pumps may be used. For example, a diaphragm pump or a gear pump may be used. · The tank unit 26 is not limited to being disposed inside the apparatus main body of the liquid discharge device 11, and may be an external form connected to the apparatus main body via a tube or the like.

[0180] · The liquid container 24 is not limited to a cartridge such as an ink cartridge, and may be a tank configured to be detachable from the mounting section 28. · The first storage section 33 or the second storage section 35 may have a window portion through which the user can visually recognize the liquid volume.

[0181] · In the above embodiment, the on-off valve 36 may be omitted. For example, during cleaning, a configuration may be adopted in which both the first storage chamber 62 and the second storage chamber 68 are pressurized. The above embodiment also includes such a technical idea. Even in the case of this technical idea, a tank unit 26 and a liquid discharge device 11 can be provided that can adjust the liquid levels of the two storage chambers 62 and 68 to an appropriate height with a simple configuration.

[0182] · A second introduction section 75 may be provided in the second storage section 35, and during liquid circulation, the liquid from the liquid discharge head 23 may return to the second storage chamber 68 through the recovery flow path 39. · The liquid discharge device may be an inkjet printing device. And the printing device may be provided with the tank unit 26.

[0183] · Instead of pressure cleaning, suction cleaning may be performed. In suction cleaning, a capping state is achieved in which the cap abuts against the nozzle surface 21 of the liquid discharge head 23 so as to surround all the nozzles 22. By driving a suction pump to create a negative pressure in the closed space formed by the cap and the nozzle surface 21, the liquid is forcibly discharged from the nozzles.

[0184] · The liquid ejection device 11 may be a liquid ejection device that ejects liquids other than ink. The state of the liquid ejected as minute droplets from the liquid ejection device shall include granular, teardrop-shaped, and those trailing in a thread-like form. The liquid referred to here may be any material that can be ejected from the liquid ejection device. For example, the liquid may be in a state when the substance is in a liquid phase, and shall include highly viscous or low-viscosity liquids, sols, gels, water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals, molten metals, and other fluid substances. The liquid shall include not only liquids as a state of matter, but also those in which particles of functional materials made of solids such as pigments and metal particles are dissolved, dispersed, or mixed in a solvent. Representative examples of the liquid include ink as described in the above embodiment, pretreatment liquids and post-treatment liquids for printing, and the like.

[0185] The following describes the technical ideas derived from the above embodiment and modification examples and their effects. (A) The tank unit is a tank unit that can introduce the liquid supplied from the liquid container and can lead out the liquid toward the liquid ejection head capable of ejecting the liquid. The tank unit includes a first introduction part for introducing the liquid supplied from the liquid container, a first storage chamber for storing the liquid introduced from the first introduction part, a first air release part for opening the first storage chamber to the atmosphere, a lead-out flow path having one end connected to the first storage chamber for leading out the liquid in the first storage chamber, a second storage chamber connected to the other end of the lead-out flow path for storing the liquid supplied from the first storage chamber, a second air release part for opening the second storage chamber to the atmosphere, and an opening / closing valve for opening and closing the lead-out flow path. The first introduction part is connected to the first storage chamber through an opening at an intermediate position in the vertical direction of the first storage chamber.

[0186] According to this configuration, without performing supply control or the like, the liquid levels of the two storage chambers can be set at appropriate heights. (B) In the above tank unit, the opening may be located below the center in the first storage chamber in the vertical direction.

[0187] According to this configuration, when there is liquid movement among the first storage chamber, the second storage chamber, and the liquid container due to environmental changes or the like, it is possible to prevent the liquid from overflowing from the storage chamber or the like. (C) In the above tank unit, a liquid level detection unit capable of detecting the liquid level of the liquid in the first storage chamber may be further provided.

[0188] According to this configuration, it is possible to detect that the liquid in the liquid container has decreased and to prevent the liquid in the first storage chamber from overflowing. (D) In the above tank unit, the on-off valve may include a one-way valve that allows the flow of liquid from the first storage chamber to the second storage chamber and restricts the flow in the direction from the second storage chamber to the first storage chamber.

[0189] According to this configuration, a valve drive source becomes unnecessary. (E) In the above tank unit, the first storage chamber and the second storage chamber may be provided such that at least a part thereof overlaps in the vertical direction.

[0190] According to this configuration, an efficient layout of the first storage chamber and the second storage chamber is possible. (F) In the above tank unit, a lead-out portion that communicates with the second storage chamber and can lead out the liquid in the second storage chamber toward the liquid discharge head, and a second introduction portion that communicates with the first storage chamber and can introduce the liquid recovered from the liquid discharge head may be further provided.

[0191] According to this configuration, the liquid levels of the first storage chamber and the second storage chamber can be maintained at the same liquid level height. (G) In the above tank unit, a filter provided between the second storage chamber and the lead-out portion and capable of capturing foreign matter contained in the liquid may be further provided.

[0192] According to this configuration, it is possible to capture foreign matter mixed in due to replacement of the liquid container, foreign matter due to circulation, and the like. (H) In the above-described tank unit, the first storage chamber may have a covering portion inside, and the covering portion may be provided vertically above the second introduction portion that opens to the lower surface inside the first storage chamber.

[0193] According to this configuration, it is possible to suppress the ink recovered in the first storage chamber from splashing throughout the first storage chamber. (I) The liquid ejection device includes a liquid ejection head capable of ejecting a liquid, the above-described tank unit, a supply flow path that communicates the lead-out portion and the liquid ejection head, and a recovery flow path that communicates the liquid ejection head and the second introduction portion.

[0194] According to this configuration, as the liquid ejection device, the same effect as the above-described tank unit can be obtained. (J) The above-described liquid ejection device may further include an inclination detection unit that detects the inclination of the tank unit.

[0195] According to this configuration, since the change amount of the liquid surface due to the inclination can be suppressed to be small, the variation in liquid surface detection can be reduced. (K) The above-described liquid ejection device may further include a pressurization unit that communicates with the second atmosphere release portion and can pressurize the inside of the second storage chamber.

[0196] According to this configuration, pressurized cleaning becomes possible.

Explanation of Reference Numerals

[0197] 11... Liquid ejection device, 12... Medium, 13... Medium storage unit, 14... Stacker, 15... Operation Section, 15a... Display section, 16... Image reading section, 17... Automatic feeding section, 19... Control section, 21... Nozzle surface, 22... Nozzle, 23... Liquid ejection head, 24, 24C, 24K, 24M, 24Y... Liquid container, 25... Supply unit, 26... Tank unit, 27... Driving mechanism, 28... Mounting section, 28o... Insertion port, 29... Accommodation chamber, 30... Pouring section, 31... Discharge valve, 31a... Valve body, 31b... Spring, 31c... Protrusion, 33... First storage section, 33a... Atmosphere opening, 34... Discharge flow path, 35... Second storage section, 35a... Atmosphere opening, 36... On-off valve, 37... Supply flow path, 38... Supply valve, 39... Recovery flow path, 40... Circulation valve, 41... Liquid chamber, 42... Flexible member, 44... First connection section, 45... Second connection section, 47... Pressurizing section, 48... Switching mechanism, 49... Pressure sensor, 50... Atmosphere release path, 51... Pressurizing flow path, 52... Connection flow path, 53... Air chamber, 54... Spring, 55... Air flow path, 57... Pressurizing mechanism, 58... Micro-pressurizing section, 60... First introduction section, 60a... Introduction port, 60G... Introduced gas phase section, 61... Introduction valve, 61a... Valve body, 62b... Valve body, 62... First storage chamber, 62L... First liquid phase section, 62G... First gas phase section, 63... Liquid level detection section, 63a... First detection section, 63b... Second detection section, 63c... Third detection section, 63d... Terminal, 64... First atmosphere release section, 65... Ceiling, 66... First liquid level, 67... Liquid level, 68... Second storage chamber, 68L... Second liquid phase section, 68G... Second gas phase section, 69... Second atmosphere release section, 70... Second liquid level, 72... Capillary section, 73a... First selection valve, 73b... Second selection valve, 73c... Third selection valve, 73d... Fourth selection valve, 73e... Fifth selection valve, 73f... Sixth selection valve, 73g... Seventh selection valve, 73h... Eighth selection valve, 73i... Ninth selection valve, 73j... Tenth selection valve, 73k... Eleventh selection valve, 74... Discharge section, 75... Second introduction section, 80... Frame, 81... Top plate, 82... Guide path, 83... First biasing member, 84... Engagement lever, 85... Second biasing member, 86... First inclined surface, 87... Second inclined surface, 88... Covering section, 90... Support member, 90a... Bottom plate, 90b... Side rib, 91... Rotation axis, 92... Lock lever, 93... Extended section, 94... Axis, 96... Guide recess, 96a... Guide hole, 96b... Wall section, 97... Guide section, 98... Tilt detection section, 100... Filter, 101... Valve body, 102... Shaft section, 103... Valve section, 103a... Valve plate section, 104... Stopper section, 105... Lip section, 106... Fin section, 142... First end wall, 143... Upper wall, 144... Bottom wall, 145... First side wall, 146... Second side wall147…Second end wall, 150…Circuit board, 241…Release part, 247…Guide part, 247a…First guide part, 247b…Second guide part, 248…Positioning protrusion, 273…Extrusion mechanism, 331…Partition wall, 332…Valve hole, 333…Valve seat, 430…Identification part, 447…Receiving part, 447a…First receiving part, 447b…Second receiving part, 448…Positioning hole, 497…Engaging part, 521…Connection terminal, 525…Memory medium, 602…Regulating part, 603…Opening, 604…Lower end, 605…Spatter prevention wall, 606…Induction groove, 607…Protrusion, SH…Standard position, LP…Mid-height of the first storage chamber, HL…Center of the first storage chamber in the vertical direction, Z…Vertical direction.,

Claims

1. A tank unit that can introduce a liquid supplied from a liquid container and can lead out the liquid toward a liquid discharge head capable of discharging the liquid, a first introduction part for introducing the liquid supplied from the liquid container; a first storage chamber for storing the liquid introduced from the first introduction part; a first atmosphere release part for opening the inside of the first storage chamber to the atmosphere; a lead-out flow path having one end connected to the first storage chamber for leading out the liquid in the first storage chamber; a second storage chamber connected to the other end of the lead-out flow path for storing the liquid supplied from the first storage chamber; a second atmosphere release part for opening the inside of the second storage chamber to the atmosphere; and an opening / closing valve capable of opening and closing the lead-out flow path, the first introduction part is connected to the first storage chamber through an opening at an intermediate position in the vertical direction of the first storage chamber, the second storage chamber is provided at a position where the opening is located at an intermediate position in the vertical direction of the second storage chamber, one end of the lead-out flow path is located below the opening, A tank unit characterized by the above.

2. The tank unit according to claim 1, wherein the opening is located below the center in the first storage chamber in the vertical direction.

3. The tank unit according to claim 1 or claim 2, further comprising a liquid level detection part capable of detecting the liquid level of the liquid in the first storage chamber.

4. The tank unit according to any one of claims 1 to 3, wherein the opening / closing valve includes a one-way valve that allows the flow of liquid from the first storage chamber toward the second storage chamber and restricts the flow in the direction from the second storage chamber toward the first storage chamber.

5. The tank unit according to any one of claims 1 to 4, wherein the first storage chamber and the second storage chamber are provided such that at least a part of them overlaps in the vertical direction.

6. A discharge part that communicates with the second storage chamber and can discharge the liquid in the second storage chamber toward the liquid discharge head; A second introduction part that communicates with the first storage chamber and can introduce the liquid recovered from the liquid discharge head; The tank unit according to any one of claims 1 to 5, further comprising:

7. The tank unit according to claim 6, further comprising a filter provided between the second storage chamber and the discharge part and capable of capturing foreign matter contained in the liquid.

8. The first storage chamber has a covering part inside, The tank unit according to claim 6 or 7, wherein the covering part is provided vertically above the second introduction part that opens to the lower surface in the first storage chamber.

9. A liquid discharge head capable of discharging liquid; The tank unit according to any one of claims 6 to 8; A supply flow path that communicates the discharge part and the liquid discharge head; A recovery flow path that communicates the liquid discharge head and the second introduction part; A liquid discharge device, comprising:

10. The liquid discharge device according to claim 9, further comprising an inclination detection part that detects the inclination of the tank unit.

11. The liquid discharge device according to claim 9 or 10, further comprising a pressurization part that communicates with the second air release part and can pressurize the inside of the second storage chamber.

12. A plurality of the one-way valves are provided in parallel in the discharge flow path. The tank unit according to claim 4, characterized in that...

13. The lead-out part is located below the opening part. The tank unit according to claim 6, characterized in that...

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