LIQUID EJECTION DEVICE AND METHOD FOR CONTROLLING LIQUID EJECTION DEVICE

Abstract

To provide a liquid discharge device configured so that a passage through which liquid flows can be prevented from being complicated and a time which is required in a plurality of processes such as exhaust circulation and non-exhaust circulation can be reduced.SOLUTION: The liquid discharge device is provided with: a first storage part 33 that stores liquid; a second storage part 35, communicating with the first storage part 33 through a communication path 34, to which liquid is supplied from the first storage part 33; a supply passage 37 through which liquid is supplied from the second storage part 35 to a liquid discharge head 23; a recovering passage 39 through which liquid is recovered from the liquid discharge head 23 into the first storage part 33; a pressurizing part 47 that pressurizes the inside of the second storage part 35; and a control part. The supply passage 37, the liquid discharge head 23 and the recovering passage 39 constitute a circulation passage 11a through which liquid can be circulated. The control part can execute exhaust-circulation by which liquid is circulated in the circulation passage 11a while making a nozzle 22 eject liquid and non-exhaust-circulation by which liquid is circulated in the circulation passage 11a without making the nozzle 22 eject liquid.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] For example, Patent Document 1 discloses a recording device that is an example of a liquid ejection device that prints by ejecting ink, an example of a liquid, from nozzles formed in a recording head, an example of a liquid ejection head. The recording device disclosed in Patent Document 1 includes a circulation path that supplies ink from an ink tank, an example of a second storage unit, to the nozzles, and a circulation path that recovers ink from the nozzles to a sub-tank, an example of a first storage unit. The recording device disclosed in Patent Document 1 also includes a valve that can open and close the circulation path and an air pump, an example of a pressurizing unit. With the valve open, the air pump pressurizes the ink tank, thereby sending ink to the circulation path. Some of the ink sent to the circulation path is discharged from the nozzles. The remaining ink passes through the circulation path and is recovered in the sub-tank. In this manner, ink circulates from the ink tank to the sub-tank. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-349843 Summary of the Invention [Problem to be solved by the invention]

[0004] It is conceivable to perform multiple processes for circulating the liquid between the first reservoir, the liquid ejection head, and the second reservoir. In this case, if the liquid flow path differs for each process, the path may become complicated. Furthermore, as in the liquid ejection device described in Patent Document 1, if the second reservoir is pressurized by the pressurizing unit with the valve open, it may take a long time for the pressure in the second reservoir to increase to the pressure required to flow the liquid from the second reservoir to the liquid ejection head. [Means for solving the problem]

[0005] A liquid ejection device that solves the above problem includes a liquid ejection head capable of ejecting liquid from a nozzle, a first reservoir that stores the liquid, a second reservoir that communicates with the first reservoir via a communication passage and to which the liquid is supplied from the first reservoir, a supply flow path that supplies the liquid from the second reservoir to the liquid ejection head, a recovery flow path that recovers the liquid from the liquid ejection head to the first reservoir, a first valve that is provided in the communication passage and is capable of opening and closing the communication passage, a second valve that is provided in the supply flow path and is capable of opening and closing the supply flow path, a pressurizing unit that pressurizes the second reservoir, and a control unit, wherein the supply flow path, the liquid ejection head, and the recovery flow path form a circulation path that can circulate the liquid, and the control unit controls the supply flow path to It is possible to perform a discharge circulation in which the liquid is circulated in the circulation path while discharging the liquid from the nozzle by closing the communicating passage with the first valve and the supply flow path with the second valve, and the pressure inside the second storage section is pressurized to a first pressure by the pressurizing unit, and then the supply flow path is opened by the second valve; and a non-discharge circulation in which the liquid is circulated in the circulation path without discharging the liquid from the nozzle by closing the communicating passage with the first valve and the supply flow path with the second valve, and then the pressure inside the second storage section is pressurized to a second pressure lower than the first pressure by the pressurizing unit, and then the supply flow path is opened by the second valve.

[0006] A control method for a liquid ejection device that solves the above-mentioned problems includes a liquid ejection head capable of ejecting liquid from a nozzle, a first reservoir that stores the liquid, a second reservoir that communicates with the first reservoir via a communication path and to which the liquid is supplied from the first reservoir, a supply flow path that supplies the liquid from the second reservoir to the liquid ejection head, a recovery flow path that recovers the liquid from the liquid ejection head to the first reservoir, a first valve that is provided in the communication path and is capable of opening and closing the communication path, a second valve that is provided in the supply flow path and is capable of opening and closing the supply flow path, and a pressurizing unit that pressurizes the inside of the second reservoir, wherein the supply flow path, the liquid ejection head, and the recovery flow path constitute a circulation path that can circulate the liquid, When performing discharge circulation in which the liquid is circulated within the circulation path while being discharged, the first valve closes the connecting passage and the second valve closes the supply flow path, and the pressure unit pressurizes the second storage section to a first pressure that is greater than the meniscus breakdown pressure of the nozzle, and then the second valve opens the supply flow path.When performing non-discharge circulation in which the liquid is circulated within the circulation path without being discharged from the nozzle, the first valve closes the connecting passage and the second valve closes the supply flow path, and the pressure unit pressurizes the second storage section to a second pressure that is less than the meniscus breakdown pressure, and then the second valve opens the supply flow path. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view of an embodiment of a liquid ejection device. [Figure 2] FIG. 1 is a schematic diagram of a liquid ejection device. [Figure 3] FIG. 2 is a cross-sectional view showing a part of a planar flow channel. [Figure 4] FIG. 2 is a perspective view showing a supply unit and a recovery unit. [Figure 5] FIG. 2 is a perspective view showing a supply unit and a recovery unit. [Figure 6] FIG. 2 is an exploded perspective view showing a supply unit and a recovery unit. [Figure 7] FIG. 2 is an exploded perspective view showing a supply unit and a recovery unit. [Figure 8] 10 is a flowchart showing a discharge circulation routine. [Figure 9] 10 is a flowchart showing a slight pressurization and discharge routine. [Figure 10] 10 is a flowchart illustrating a non-drain circulation routine. [Figure 11] 10 is a flowchart showing a filling circulation routine. DETAILED DESCRIPTION OF THE INVENTION

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

[0009] In the drawings, the liquid ejection device is placed on a horizontal plane, and the direction of gravity is indicated by the Z axis, while directions along the horizontal plane are indicated by the X and Y axes. The X, Y, and Z axes are perpendicular to each other. <Liquid discharge device> 1 , liquid ejection device 11 may include a medium storage unit 13 capable of storing medium 12, a stacker 14 that receives printed medium 12, and an operation unit 15 such as a touch panel for operating liquid ejection device 11. Liquid ejection device 11 may also include an image reading unit 16 that reads an image of a document, and an automatic feed unit 17 that sends the document to image reading unit 16.

[0010] As shown in FIGS. 1 and 2, the liquid ejection device 11 includes a liquid ejection head 23, a first storage section 33, a second storage section 35, a supply flow path 37, a recovery flow path 39, a first valve 36, a second valve 38, a pressurizing section 47, and a control section 19. The supply flow path 37, the liquid ejection head 23, and the recovery flow path 39 form a circulation path 11a that can circulate the liquid. The liquid ejection device 11 may include a temperature detection section 80. The liquid ejection device 11 may include a third valve 40. The liquid ejection device 11 may include a planar flow path 75. The liquid ejection device 11 may include a supply section 81 and a recovery section 82. The liquid ejection device 11 may include a maintenance member 91.

[0011] 2, the liquid ejection device 11 may include a supply mechanism 25, a drive mechanism 26, and a switching mechanism 48. The supply mechanism 25 supplies the liquid contained in the liquid storage portion 24 to the liquid ejection head 23. The supply mechanism 25 includes a first reservoir 33, a second reservoir 35, a supply flow path 37, a recovery flow path 39, a first valve 36, a second valve 38, and a pressurizing portion 47. The drive mechanism 26 drives the supply mechanism 25.

[0012] The liquid ejection device 11 may include a plurality of supply mechanisms 25. The plurality of supply mechanisms 25 may each supply a different type of liquid to the liquid ejection head 23. For example, the liquid ejection device 11 may perform color printing by ejecting ink of a plurality of colors supplied by the plurality of supply mechanisms 25. One drive mechanism 26 may drive the plurality of supply mechanisms 25 collectively. The liquid ejection device 11 may include a plurality of drive mechanisms 26 that drive the plurality of supply mechanisms 25 individually.

[0013] Supply mechanism 25 may include an attachment part 28 to which liquid storage part 24 is detachably attached. Liquid storage part 24 may include a storage chamber 29 that stores liquid, an outlet part 30 for discharging the liquid stored in storage chamber 29, and a storage part-side valve 31 provided in outlet part 30. Storage chamber 29 in this embodiment is an enclosed space that is not in communication with the atmosphere. Before being attached to attachment part 28, liquid storage part 24 may store an amount of liquid greater than the amount of liquid that supply mechanism 25 can hold.

[0014] The driving mechanism 26 may include a switching mechanism 48 connected to the pressurizing unit 47 and a pressure sensor 49 that detects pressure. The driving mechanism 26 may include an atmosphere-open path 50 connected to the first storage unit 33, a pressurized flow path 51 connected to the second storage unit 35, and a connecting flow path 52 that connects the atmosphere-open path 50 and the pressurized flow path 51 to the pressurizing unit 47.

[0015] The driving mechanism 26 may have a first supply membrane 64. The first supply membrane 64 is a membrane that allows gas to pass through easily but does not allow liquid to pass through easily. The first supply membrane 64 is located in the atmosphere open path 50. The first supply membrane 64 reduces the risk of liquid flowing through the atmosphere open path 50. The first supply membrane 64 reduces the risk of liquid flowing from the first reservoir 33 to the driving mechanism 26.

[0016] The driving mechanism 26 may have a second supply membrane 69. The second supply membrane 69 is a membrane that allows gas to pass easily but does not allow liquid to pass easily. The second supply membrane 69 is located in the pressurized flow path 51. The second supply membrane 69 reduces the risk of liquid flowing through the pressurized flow path 51. The second supply membrane 69 reduces the risk of liquid flowing from the second reservoir 35 to the driving mechanism 26.

[0017] The drive mechanism 26 may include an air chamber 53 separated from the liquid chamber 41 by 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 presses the flexible member 42 to reduce pressure fluctuations in the liquid within the recovery flow path 39 and the liquid ejection head 23. The liquid chamber 41 is partially constituted by the flexible member 42, and its volume changes as the flexible member 42 deforms.

[0018] The switching mechanism 48 includes a thin tube section 72 provided in the connection flow path 52, and first selection valves 73a to eleventh selection valves 73k that can open and close the flow path. The thin tube section 72 is a meandering tube that is thin enough that the flow of liquid is significantly restricted compared to the flow of air.

[0019] When the first selection valve 73a is opened, it connects the air flow path 55 to the atmosphere. When the second selection valve 73b is opened, it connects the air flow path 55 to the pressure sensor 49. When the third selection valve 73c is opened, it opens the air flow path 55 and connects the pressurizing unit 47 to the air chamber 53.

[0020] The fourth selection valve 73d, when opened, connects the connecting flow path 52 between the pressurizing unit 47 and the eighth selection valve 73h to the atmosphere. The fifth selection valve 73e, when opened, connects the connecting flow path 52 to the pressure sensor 49. The sixth selection valve 73f and the seventh selection valve 73g, when opened, connect the connecting flow path 52 to the atmosphere. The eighth selection valve 73h, when opened, opens the connecting flow path 52. The ninth selection valve 73i, when opened, connects the thin tube unit 72 to the atmosphere. The tenth selection valve 73j, when opened, opens the atmosphere release path 50, connecting the first storage unit 33 to the connecting flow path 52. The eleventh selection valve 73k, when opened, opens the pressurizing flow path 51, connecting the second storage unit 35 to the connecting flow path 52.

[0021] When the pressure in air chamber 53 is changed, switching mechanism 48 opens second selection valve 73b to fourth selection valve 73d and closes the other selection valves. When pressurizing unit 47 is driven in the forward direction in this state, air in air chamber 53 is discharged through air flow path 55 and connecting flow path 52, and the pressure in air chamber 53 decreases. When pressurizing unit 47 is driven in the reverse direction in this state, air is sent into air chamber 53 through connecting flow path 52 and air flow path 55, and the pressure in air chamber 53 increases. At this time, pressure sensor 49 may detect the pressure in air flow path 55 and air chamber 53. Control unit 19 may control the driving of pressurizing unit 47 based on the detection result of pressure sensor 49.

[0022] When opening the first reservoir 33 to the atmosphere, the switching mechanism 48 opens the sixth selection valve 73f and the tenth selection valve 73j. The first reservoir 62 communicates with the atmosphere via the atmosphere open path 50 and the connecting path 52.

[0023] When the second reservoir 35 is opened to the atmosphere, the switching mechanism 48 opens the seventh selection valve 73g and the eleventh selection valve 73k. The second reservoir 68 is in communication with the atmosphere via the pressurizing flow path 51 and the connecting flow path 52.

[0024] When pressurizing the second reservoir 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 unit 47 is driven in the forward direction in this state, air flows into the second reservoir 68 via the air flow path 55, the connecting flow path 52, and the pressurized flow path 51, and the pressure in the second reservoir 68 increases. At this time, the pressure sensor 49 may detect the pressure in the connecting flow path 52, the pressurized flow path 51, and the second reservoir 68. The control unit 19 may control the driving of the pressurizing unit 47 based on the detection result of the pressure sensor 49.

[0025] In this embodiment, a pressurizing mechanism 57 is configured including the pressurizing unit 47, the air chamber 53, and an air flow path 55 that connects the pressurizing unit 47 and the air chamber 53, and a slight pressurizing unit 58 is configured by adding the liquid chamber 41 to the pressurizing mechanism 57. The slight pressurizing unit 58 has the liquid chamber 41 and the pressurizing mechanism 57 that can pressurize the flexible member 42 from outside the liquid chamber 41. The slight pressurizing unit 58 pressurizes the liquid in the recovery flow path 39.

[0026] <Liquid ejection head> The liquid ejection head 23 is capable of ejecting liquid from nozzles 22. The nozzles 22 are provided on the nozzle surface 21. The liquid ejection head 23 may be arranged so that the nozzle surface 21 is inclined relative to the horizontal. The liquid ejection head 23 may perform printing by ejecting liquid onto the medium 12 in an inclined position. The liquid ejection head 23 of this embodiment is a line type that is provided across the width direction of the medium 12. The liquid ejection head 23 may also be configured as a serial type that performs printing while moving in the width direction of the medium 12.

[0027] The liquid ejection head 23 may have a first connection portion 44 and a second connection portion 45. In the inclined posture, the first connection portion 44 may be disposed at a higher position than the second connection portion 45. <Maintenance parts> The maintenance member 91 performs various maintenance operations on the liquid ejection head 23. The maintenance operations performed by the maintenance member 91 may include wiping, flushing, and dry suction. Wiping may be performed by displacing the maintenance member 91 along the nozzle surface 21. In wiping, the maintenance member 91 wipes away liquid adhering to the nozzle surface 21. Flushing may be performed by ejecting liquid from the nozzles 22 toward the maintenance member 91 while the nozzle surface 21 is separated from the maintenance member 91. Dry suction may be performed by discharging liquid that has accumulated in the maintenance member 91 due to flushing from the maintenance member 91 to a drain tank (not shown).

[0028] <Supply Channel and Recovery Channel> The supply flow path 37 supplies the liquid from the second storage section 35 to the liquid ejection head 23. The supply flow path 37 may be connected to a second connection section 45 of the liquid ejection head 23. The upstream end of the supply flow path 37 may be connected to the second storage section 35, and the downstream end of the supply flow path 37 may be connected to the second connection section 45.

[0029] The recovery channel 39 recovers the liquid from the liquid ejection head 23 to the first reservoir 33. The recovery channel 39 may be connected to a first connection portion 44 of the liquid ejection head 23. The upstream end of the recovery channel 39 may be connected to the first connection portion 44, and the downstream end of the recovery channel 39 may be connected to the first reservoir 33.

[0030] <First storage section> First reservoir 33 stores liquid. An upstream end of communication passage 34 may be connected to first reservoir 33. Liquid is supplied from liquid storage section 24 to first reservoir 33. First reservoir 33 may have an introduction section 60 that can introduce liquid stored in liquid storage section 24 attached to attachment section 28. First reservoir 33 may have an apparatus-side valve 61 provided in introduction section 60, a first reservoir chamber 62 that stores liquid, and a liquid level sensor 63 that detects the amount of liquid stored in first reservoir chamber 62.

[0031] The device-side valve 61 opens together with the container-side valve 31 when the liquid container 24 is attached to the attachment portion 28. While the liquid container 24 is attached to the attachment portion 28, the device-side valve 61 remains open together with the container-side valve 31. By configuring the device-side valve 61 to open before the container-side valve 31 when the liquid container 24 is attached to the attachment portion 28, the risk of liquid leaking from the liquid container 24 can be reduced.

[0032] The introduction part 60 is provided so as to penetrate the ceiling 65a of the first storage chamber 62. The lower end of the introduction part 60 is located inside the first storage chamber 62 and below the ceiling 65a. The upper end of the introduction part 60 is located outside the first storage chamber 62 and above the ceiling 65a. The introduction part 60 is connected to the outlet part 30 provided in the liquid storage part 24 by attaching the liquid storage part 24 to the attachment part 28.

[0033] The lower end of the introduction portion 60 is positioned below the nozzle surface 21. As a result, a first liquid level 66 of the liquid stored in the first storage portion 33 fluctuates within a range lower than the nozzle surface 21. Specifically, the liquid in the liquid storage portion 24 is supplied to the first storage portion 33 via the outlet portion 30 and the introduction portion 60 by a hydraulic head. Air is introduced from the first storage portion 33 via the introduction portion 60 and the outlet portion 30 into the liquid storage portion 24 in an amount corresponding to the amount of liquid supplied to the first storage portion 33. The first liquid level 66 rises by the amount of the supplied liquid. When the first liquid level 66 reaches the lower end of the introduction portion 60, the inflow of air from the first storage portion 33 to the liquid storage portion 24 is restricted. Because the storage chamber 29 is sealed, restricting the inflow of air reduces the pressure within the storage chamber 29 by the amount of the supplied liquid. When the negative pressure in storage chamber 29 becomes greater than the head of the liquid in storage chamber 29, the supply of liquid from liquid storage portion 24 to first reservoir 33 is restricted.

[0034] The first liquid level 66 descends as liquid is supplied from the first storage section 33 to the second storage section 35. When the first liquid level 66 descends and air flows into the storage chamber 29 via the inlet section 60 and the outlet section 30, the negative pressure within the storage chamber 29 decreases. When the negative pressure within the storage chamber 29 becomes smaller than the head of the liquid within the storage chamber 29, liquid is supplied from the liquid storage section 24 to the first storage section 33. Therefore, while liquid is stored in the liquid storage section 24, the first liquid level 66 is maintained at a standard position, which is a position near the lower end of the inlet section 60. When the liquid stored in the liquid storage section 24 runs out, the first liquid level 66 is positioned below the standard position.

[0035] The liquid level sensor 63 may detect whether the first liquid level 66 is at a standard position, whether the first liquid level 66 is at a position below the standard position, or whether the first liquid level 66 is at a full position above the standard position. When the first liquid level 66 is at the full position, the first reservoir 33 stores the maximum amount of liquid.

[0036] An inlet 33a is formed in first reservoir 33, through which the liquid in recovery passage 39 flows in. Inlet 33a is located below the center of first reservoir 33. Inlet 33a may be a through-hole that penetrates first bottom 65b, which is the bottom of first reservoir chamber 62. Inlet 33a may be located in the center of first bottom 65b. First reservoir 62 and recovery passage 39 are in communication via inlet 33a.

[0037] The standard position of the first liquid level 66 is located above the position of the inlet 33a in the first storage chamber 62. Therefore, when the first liquid level 66 is at the standard position, the liquid in the first storage section 33 can be supplied to the liquid ejection head 23 via the recovery channel 39.

[0038] <Second storage section> Second reservoir 35 communicates with first reservoir 33 via a communication passage 34. The downstream end of communication passage 34 may be connected to second reservoir 35. Liquid is supplied to second reservoir 35 from first reservoir 33.

[0039] The second storage section 35 may be supplied with liquid from the first storage section 33 via the communication passage 34 due to a head difference. When the first storage chamber 62 and the second storage chamber 68 are at atmospheric pressure, a second liquid level 70 of the liquid in the second storage section 35 is at the same height as the first liquid level 66. In other words, the second liquid level 70 is maintained at a standard position that is approximately the same height as the lower end of the introduction section 60, and fluctuates within a range lower than the nozzle surface 21. The liquid in the liquid ejection head 23 is maintained at a negative pressure due to a head difference between the liquid in the first storage section 33 and the second storage section 35. When the liquid is consumed in the liquid ejection head 23, the liquid stored in the second storage section 35 is supplied to the liquid ejection head 23.

[0040] The second reservoir 35 may be formed with a supply port 35a that supplies liquid into the supply flow path 37. The supply port 35a may be located below the center of the second reservoir 35. The supply port 35a may be a through-hole that penetrates a second bottom 68b, which is the bottom of the second reservoir 68. The supply port 35a may be located at the center of the second bottom 68b. The second reservoir 68 and the supply flow path 37 are in communication with each other via the supply port 35a. The second reservoir 35 may be provided with a filter 35b. The filter 35b is located in the second reservoir 68. The filter 35b covers the supply port 35a.

[0041] <First valve> The first valve 36 is provided in the communication passage 34. The first valve 36 can open and close the communication passage 34. The first valve 36 is a one-way valve. The first valve 36 allows the flow of liquid from the first reservoir 33 to the second reservoir 35. The first valve 36 restricts the flow of liquid from the second reservoir 35 to the first reservoir 33. The first valve 36 closes the communication passage 34 when the pressure in the second reservoir 35 is greater than the pressure in the first reservoir 33.

[0042] <Second and third valves> The second valve 38 is provided in the supply flow path 37. The second valve 38 is capable of opening and closing the supply flow path 37. The third valve 40 is provided in the recovery flow path 39. A slight pressure applying unit 58 is provided in the recovery flow path 39 between the third valve 40 and the liquid ejection head 23. A liquid chamber 41 is located in the recovery flow path 39 between the third valve 40 and the liquid ejection head 23. The third valve 40 is capable of opening and closing the recovery flow path 39. The opening and closing of the second valve 38 and the third valve 40 is controlled by the control unit 19.

[0043] The second valve 38 and the third valve 40 may be closed when the power to the liquid ejection device 11 is turned off. By closing the supply flow path 37 and the recovery flow path 39, it is possible to reduce the risk of liquid leaking from the liquid ejection head 23, for example, even if the liquid ejection device 11 is subjected to vibration or impact.

[0044] The second valve 38 and the third valve 40 open when printing is performed by the liquid ejection device 11. As a result, during printing, liquid is supplied from the second storage section 35 to the supply flow path 37. Liquid is supplied from the first storage section 33 to the recovery flow path 39. Liquid is supplied from the supply flow path 37 and the recovery flow path 39 to the liquid ejection head 23.

[0045] <Planar flow channel> The planar flow path 75 is located below the first reservoir 33 and the second reservoir 35. The planar flow path 75 includes a portion of the supply flow path 37 and a portion of the recovery flow path 39. Furthermore, the planar flow path 75 may include at least one of the air flow path 55, the second valve 38, and the third valve 40.

[0046] 3, the planar flow path 75 has a first flow path 76, a second flow path 77, and a third flow path 78. The first flow path 76 and the second flow path 77 each extend perpendicular to the third flow path 78. The second flow path 77 is located above the first flow path 76. The third flow path 78 connects the downstream end of the first flow path 76 and the upstream end of the second flow path 77. The third flow path 78 extends upward from the downstream end of the first flow path 76 to the upstream end of the second flow path 77.

[0047] The planar flow path 75 has a blocking portion 79. The blocking portion 79 blocks a first corner 79a formed by the downstream end of the third flow path 78 and the upstream end of the second flow path 77. The blocking portion 79 may have a triangular cross section that blocks the first corner 79a. The blocking portion 79 is separate from the components that form the planar flow path 75. The blocking portion 79 may be molded integrally with the components that form the planar flow path 75.

[0048] As shown by the arrows in FIG. 3 , the liquid flowing through the planar flow path 75 flows from the first flow path 76 to the third flow path 78 and then to the second flow path 77. When the liquid flows from the first flow path 76 to the third flow path 78, the flow direction of the liquid changes upward. When the liquid flows from the third flow path 78 to the second flow path 77, the liquid flows along the surface of the blocking portion 79. Compared to when the first corner portion 79a is not blocked by the blocking portion 79, the flow of the liquid is less likely to stagnate at the upstream end of the second flow path 77. This makes it possible to prevent bubbles from accumulating in the liquid at the upstream end of the second flow path 77.

[0049] In the planar flow path 75, a second corner 79b opposite to the first corner 79a where the blocking portion 79 is provided may be chamfered. This allows the blocking portion 79 to be formed at the first corner 79a while preventing the flow paths of the third flow path 78 and the second flow path 77 from narrowing. The blocking portion 79 may close a third corner 79c formed by the downstream end of the first flow path 76 and the upstream end of the third flow path 78. In the planar flow path 75, a fourth corner 79d opposite to the third corner 79c where the blocking portion 79 is provided may be chamfered. This allows the blocking portion 79 to be formed at the third corner 79c while preventing the flow paths of the first flow path 76 and the third flow path 78 from narrowing.

[0050] <Pressure section> As shown in FIG. 2, the pressurizing unit 47 pressurizes the second storage unit 35. As the pressurizing unit 47 pressurizes the second storage unit 35, the first valve 36 closes the communication passage 34. The pressurizing unit 47 is, for example, a tube pump that sends out air by rotating a roller while squeezing a tube. One end of a tube (not shown) included in the pressurizing unit 47 is connected to an air flow path 55, and the other end is connected to a connection flow path 52. When the pressurizing unit 47 is driven in the forward direction, it sends out air taken in from the air flow path 55 to the connection flow path 52. When the pressurizing unit 47 is driven in the reverse direction, it sends out air taken in from the connection flow path 52 to the air flow path 55.

[0051] <Temperature detection section> The temperature detection unit 80 detects the environmental temperature, which is the temperature of the environment in which the liquid ejection device 11 is used. The temperature detection unit 80 detects the temperature at the location where the temperature detection unit 80 is installed as the environmental temperature. The environmental temperature detected by the temperature detection unit 80 may be in degrees Celsius. The control unit 19 may perform various controls based on the environmental temperature detected by the temperature detection unit 80. The temperature detection unit 80 may detect the temperature of the printed medium 12. The temperature detection unit 80 may be installed near the liquid ejection head 23.

[0052] <Supply section and recovery section> 4, the supply unit 81 and the recovery unit 82 may each include a tube 83. Each of the supply unit 81 and the recovery unit 82 may include a plurality of tubes 83. The plurality of tubes 83 in the supply unit 81 allow inks of different colors to flow through them. The plurality of tubes 83 in the recovery unit 82 allow inks of different colors to flow through them. Each of the supply unit 81 and the recovery unit 82 may include four tubes 83.

[0053] Each of the plurality of tubes 83 in the supply unit 81 constitutes a part of a different supply flow path 37. The tubes 83 in the supply unit 81 include ends of the supply flow paths 37. Each of the plurality of tubes 83 in the recovery unit 82 constitutes a part of a different recovery flow path 39. The tubes 83 in the recovery unit 82 include ends of the recovery flow path 39. In each of the supply unit 81 and the recovery unit 82, ends of the tubes 83 are connected to the liquid ejection head 23.

[0054] Each of the supply unit 81 and the recovery unit 82 may include a joint unit 84, an arm unit 86, and a clamp unit 87. The joint unit 84 is attached to the plurality of tubes 83 in each of the supply unit 81 and the recovery unit 82 by outsert molding. The joint unit 84 has a plurality of tube insertion holes 84a formed therein. The joint unit 84 of this embodiment has four tube insertion holes 84a formed therein. The four tube insertion holes 84a are aligned adjacent to one another in one direction. In the flow direction of liquid flowing from the tubes 83 to the liquid ejection head 23, the downstream ends of the plurality of tubes 83 may be inserted into different tube insertion holes 84a.

[0055] 5, a first screw insertion hole 84b is formed in the joint part 84. In this embodiment, two first screw insertion holes 84b are formed in the joint part 84. The two first screw insertion holes 84b are positioned in the joint part 84 so as to sandwich the four tube insertion holes 84a. A screw member 85 is inserted into each of the two first screw insertion holes 84b. The screw members 85 inserted into the first screw insertion holes 84b are fastened to screw insertion holes (not shown) of the liquid ejection head 23, thereby connecting the tube 83 and the joint part 84 to the liquid ejection head 23.

[0056] The arm portion 86 is integral with the joint portion 84. The arm portion 86 extends from each of one end and the other end of the joint portion 84. The supply portion 81 and the recovery portion 82 may each include a plurality of clamp portions 87. The plurality of clamp portions 87 are attached to different positions on the tubes 83. Each of the plurality of clamp portions 87 includes a first clamp portion 88 and a second clamp portion 89. Each of the plurality of clamp portions 87 clamps the plurality of tubes 83 from both sides using the first clamp portion 88 and the second clamp portion 89.

[0057] As shown in Figures 6 and 7, the supply unit 81 and the recovery unit 82 may include a protective unit 90. The protective unit 90 may be a long strip-shaped film. The protective unit 90 may be a polyester film. The protective unit 90 is positioned so as to cover the multiple tubes 83 from one side. An insertion hole 90a is formed at the end of the protective unit 90. A plurality of insertion holes 90a may be positioned at equal intervals from each other in the short direction of the protective unit 90.

[0058] The first clamping portion 88 includes a first main body 88a. A plurality of first recesses 88b are formed on the side surface of the first main body 88a. In the first clamping portion 88 that overlaps the plurality of tubes 83 from above, the plurality of first recesses 88b are located on the underside of the first main body 88a.

[0059] Each of the multiple first recesses 88b opens toward the second clamp portion 89. In this embodiment, four first recesses 88b are formed in the first main body 88a. The four first recesses 88b are adjacent to each other. A tube 83 is fitted into each of the four first recesses 88b. As a result, the first clamp portion 88 partially overlaps each of the multiple tubes 83.

[0060] The first clamp portion 88 has a plurality of protrusions 88g that protrude from the first body 88a toward the second clamp portion 89. Each of the plurality of protrusions 88g is inserted into an insertion hole 90a of the protector 90, thereby fixing the protector 90 to the first clamp portion 88. An end of the protector 90 is interposed between the first clamp portion 88 and the plurality of tubes 83.

[0061] The first clamp portion 88 includes two first protrusions 88c. The first protrusions 88c extend from both ends of the first main body 88a toward the second clamp portion 89. An engagement hole 88d is formed in the first protrusions 88c. The first protrusions 88c are positioned so as to sandwich the four tubes 83 from both sides. The connection portion of the arm portion 86 with the joint portion 84 may be the base end, and the tip end 86a of the arm portion 86 may be interposed between the tubes 83 and the first protrusions 88c.

[0062] The first clamp portion 88 has two second protrusions 88e. The second protrusions 88e extend from both ends of the first main body 88a. Second screw insertion holes 88f are formed in the second protrusions 88e. Screw members 85 can be inserted into the second screw insertion holes 88f. When it is necessary to fix the first clamp portion 88 to another member, the screw members 85 are inserted into the second screw insertion holes 88f, and the screw members 85 inserted into the second screw insertion holes 88f are fastened to screw insertion holes (not shown) of the other member.

[0063] The second clamping portion 89 includes a second main body 89a. A plurality of second recesses 89b are formed on the side surface of the second main body 89a. In the second clamping portion 89 that overlaps the plurality of tubes 83 from below the plurality of tubes 83, the plurality of second recesses 89b are located on the upper surface of the second main body 89a.

[0064] Each of the multiple second recesses 89b opens toward the first clamp portion 88. In this embodiment, four second recesses 89b are formed in the second main body 89a. The four second recesses 89b are adjacent to each other. A tube 83 is fitted into each of the four second recesses 89b. As a result, the second clamp portion 89 partially overlaps each of the multiple tubes 83.

[0065] The second clamp portion 89 has an engagement end portion 89d. The engagement end portion 89d is located at both ends of the second main body 89a. The second clamp portion 89 is located between first protrusions 88c located at both ends of the first main body 88a. The engagement end portion 89d is inserted into an engagement hole 88d located in the first protrusion 88c, thereby engaging with the first protrusion 88c. The first clamp portion 88 and the second clamp portion 89 are integrated. The four tubes 83 and the tip end portion 86a of the arm portion 86 may be sandwiched from both sides by the integrated first clamp portion 88 and second clamp portion 89.

[0066] <Control unit> As shown in FIG. 1, the control unit 19 controls various operations executed by the liquid ejection device 11. The control unit 19 may be configured as a circuit including: α: one or more processors that execute various processes according to a computer program; β: one or more dedicated hardware circuits that execute at least some of the various processes; or γ: a combination thereof. The hardware circuit is, for example, an application-specific integrated circuit. The processor includes a CPU and memory such as RAM and ROM, and the memory stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., computer-readable medium, includes any readable medium that can be accessed by a general-purpose or dedicated computer.

[0067] When the liquid level sensor 63 detects that the first liquid level 66 is located below the standard position, the control unit 19 may determine that the liquid storage section 24 is empty and instruct the user to replace the liquid storage section 24.

[0068] The control unit 19 can perform discharge circulation and non-discharge circulation. The control unit 19 can perform filling circulation. The control unit 19 can perform slight pressurization discharge. The control unit 19 can change the third valve 40 between closing and opening the recovery flow path 39.

[0069] Next, a method for controlling the liquid ejection device 11 will be described with reference to the flowcharts shown in Figures 8 to 11. Here, the order of steps in each control method can be arbitrarily changed within the scope that does not deviate from the purpose of each control method.

[0070] <Emission circulation> The discharge circulation routine will be described with reference to FIG. 8. The discharge circulation may be performed when the liquid storage unit 24 is first attached to the attachment unit 28. If the discharge circulation is performed when the liquid storage unit 24 is first attached to the attachment unit 28, the discharge circulation may be performed after the fill circulation. The discharge circulation may be performed during standby when no printing or the like is being performed. The discharge circulation may be performed periodically. The discharge circulation may be performed for some of the multiple supply flow paths 37 and some of the multiple recovery flow paths 39, and then for the remaining supply flow paths 37 and recovery flow paths 39.

[0071] 8, in step S101, the control unit 19 opens the third valve 40. In step S102, the control unit 19 closes the second valve 38. In step S103, the control unit 19 pressurizes the second storage unit 35 to a first pressure P1. The control unit 19 pressurizes the second storage unit 35 to the first pressure P1 by driving the pressurizing unit 47. The first pressure P1 is a pressure greater than the meniscus breakdown pressure of the nozzle 22.

[0072] In step S104, control unit 19 determines whether or not a first pressurization time T1 has elapsed since second storage unit 35 was pressurized in step S103. First pressurization time T1 is the time required for second storage unit 35 to be pressurized up to first pressure P1.

[0073] Step S104 remains NO until the first pressurization time T1 has elapsed. The control unit 19 waits until the first pressurization time T1 has elapsed. When the first pressurization time T1 has elapsed, step S104 remains YES. The control unit 19 proceeds to step S105. In step S105, the control unit 19 opens the second valve 38. In step S106, the control unit 19 pressurizes the second storage unit 35 to a first pressure P1. In step S107, the control unit 19 determines whether a first predetermined time Tp1 has elapsed since the second valve 38 was opened in step S105. The first predetermined time Tp1 is the time required for the second storage unit 35 to be pressurized to the first pressure P1 with the second valve 38 open.

[0074] The first pressurization time T1 and the first predetermined time Tp1 may be set in advance or may be changed each time discharge circulation is performed. The control unit 19 may lengthen the first pressurization time T1 and the first predetermined time Tp1 when the ambient temperature is a first temperature compared to when the ambient temperature is a second temperature higher than the first temperature. The control unit 19 may lengthen the first pressurization time T1 and the first predetermined time Tp1 the lower the ambient temperature. The control unit 19 may use different first pressurization times T1 and first predetermined times Tp1 for each of a plurality of preset temperature ranges. In this case, the same value is used as the first pressurization time T1 for different ambient temperatures within the same temperature range. The same value is used as the first predetermined time Tp1 for different ambient temperatures within the same temperature range. Different values ​​are used as the first pressurization time T1 for different ambient temperatures within different temperature ranges. Different values ​​are used as the first predetermined time Tp1 for different ambient temperatures within different temperature ranges.

[0075] The first pressurization time T1 is set so that the amount of liquid supplied from second storage unit 35 to supply flow path 37 during the first pressurization time T1 after second storage unit 35 is pressurized falls within a specified range. The first predetermined time Tp1 is set so that the amount of liquid supplied from second storage unit 35 to supply flow path 37 during the first predetermined time Tp1 after second storage unit 35 is pressurized falls within a specified range. The specified range of liquid amount is a range in which the amount of liquid required for discharge circulation can be supplied to supply flow path 37 and the amount of liquid stored in second storage unit 35 does not fall below a specified amount.

[0076] Step S107 remains NO until the first predetermined time Tp1 has elapsed. The control unit 19 waits until the first predetermined time Tp1 has elapsed. Once the first predetermined time Tp1 has elapsed, step S107 remains YES. The control unit 19 proceeds to step S108. In step S108, the control unit 19 stops pressurizing the second storage unit 35. In step S109, the control unit 19 opens the second storage unit 35 to the atmosphere. In step S110, the control unit 19 closes the second valve 38. In step S111, the control unit 19 closes the third valve 40. In step S112, the control unit 19 determines whether the liquid level recovery time has elapsed since the second valve 38 was closed in step S110. The liquid level recovery time is the time required for the second liquid level 70 of the liquid in the second storage unit 35 to reach the standard position.

[0077] Step S112 remains NO until the liquid level recovery time has elapsed. The control unit 19 waits until the liquid level recovery time has elapsed. When the liquid level recovery time has elapsed, step S112 remains YES. The control unit 19 proceeds to step S113. In step S113, the control unit 19 determines whether the processing of steps S101 to S112 has been executed for the nth time in the current discharge circulation routine.

[0078] If the current discharge and circulation routine is being executed when the liquid storage portion 24 is first attached to the attachment portion 28, in step S113 the control portion 19 makes a determination using the first predetermined number of times n1 as the nth time. The first predetermined number of times n1 may be less when the environmental temperature is below the predetermined temperature than when the environmental temperature is equal to or higher than the predetermined temperature. The first predetermined number of times n1 when the environmental temperature is below the predetermined temperature may be two times. The first predetermined number of times n1 when the environmental temperature is equal to or higher than the predetermined temperature may be three times.

[0079] If the current discharge circulation routine is being executed during standby when no printing or other operations are being performed, in step S113, the control unit 19 uses the second predetermined number of times n2 as the nth time. The second predetermined number of times n2 may be less than the first predetermined number of times n1. If the first predetermined number of times n1 is 2 or 3, the second predetermined number of times n2 may be 1.

[0080] Step S113 remains NO until the processing of steps S101 to S112 has been executed n times in the current discharge and circulation routine. The control unit 19 again executes the processing of steps S101 to S113. When the processing of steps S101 to S113 has been executed n times in the current discharge and circulation routine, step S113 remains YES. The control unit 19 proceeds to step S114. In step S114, the control unit 19 performs wiping using the maintenance member 91. In step S115, the control unit 19 executes a slight pressure discharge routine and then ends the discharge and circulation routine. At least two of steps S108, S109, S110, and S111 may be executed simultaneously.

[0081] 2, in the discharge circulation, the control unit 19 pressurizes the second storage unit 35 and opens the second valve 38 while the recovery passageway 39 is open. Therefore, the liquid flows from the second storage unit 35 into the supply passageway 37. The liquid is supplied to the liquid ejection head 23 through the supply passageway 37. A portion of the liquid supplied to the liquid ejection head 23 is discharged from the nozzle 22. The liquid is recovered from the liquid ejection head 23 into the recovery passageway 39. The liquid is returned to the first storage unit 33 through the recovery passageway 39.

[0082] In the discharge circulation, air bubbles accumulated in the liquid ejection head 23, the supply flow path 37, and the recovery flow path 39 flow together with the liquid into the first reservoir 33. This reduces the amount of air bubbles accumulated in the liquid ejection head 23, the supply flow path 37, and the recovery flow path 39.

[0083] <Minor pressure discharge> The routine for slight pressure discharge will be described with reference to Fig. 9. The slight pressure discharge may be executed when an instruction to execute slight pressure discharge is given.

[0084] 9, in step S201, the control unit 19 opens the second valve 38. In step S202, the control unit 19 opens the third valve 40. In step S203, the control unit 19 depressurizes the air chamber 53. In step S204, the control unit 19 determines whether a depressurization time has elapsed since the air chamber 53 was depressurized. The depressurization time is the time required to deform the flexible member 42 and maximize the volume of the liquid chamber 41.

[0085] Step S204 remains NO until the depressurization time has elapsed. The control unit 19 waits until the depressurization time has elapsed. Once the depressurization time has elapsed, step S204 remains YES. The control unit 19 transitions the process to step S205. In step S205, the control unit 19 closes the second valve 38. In step S206, the control unit 19 closes the third valve 40. In step S207, the control unit 19 opens the air chamber 53 to the atmosphere. In step S208, the control unit 19 performs wiping using the maintenance member 91. In step S209, the control unit 19 performs flushing using the maintenance member 91. In step S210, the control unit 19 performs dry suction using the maintenance member 91, and then ends the slight pressurization and discharge routine.

[0086] Here, steps S201 and S202 may be performed simultaneously with step S203 or after step S203. Furthermore, steps S205 and S206 may be performed during step S203, simultaneously with the completion of step S203, or after the completion of step S203.

[0087] 2, during slight pressurization and discharge, the control unit 19 opens the second valve 38 and the third valve 40 to open the supply flow path 37 and the recovery flow path 39. The control unit 19 reduces the pressure in the air chamber 53, thereby deforming the flexible member 42 and increasing the volume of the liquid chamber 41. Liquid flows into the liquid chamber 41 from the first reservoir 33 via the recovery flow path 39, and liquid also flows into the liquid chamber 41 from the second reservoir 35 via the supply flow path 37 and the recovery flow path 39.

[0088] When the volume of the liquid chamber 41 reaches its maximum, the control unit 19 closes the second valve 38 to close the supply flow path 37. The control unit 19 closes the third valve 40 to close the recovery flow path 39. The deformation of the flexible member 42 caused by the reduced pressure in the air chamber 53 is released, and the volume of the liquid chamber 41 decreases. This causes the liquid ejection device 11 to eject the liquid from the nozzle 22 using the pressurizing mechanism 57. The pressurizing mechanism 57 pressurizes the liquid chamber 41 with a pressure that breaks the meniscus formed in the nozzle 22. The amount of liquid ejected from the liquid ejection head 23 by the slight pressurized ejection is less than the amount of liquid ejected from the liquid ejection head 23 by the ejection circulation.

[0089] <Non-emission circulation> The non-discharge circulation routine will be described with reference to Fig. 10. The non-discharge circulation may be executed after the fill circulation and the discharge circulation have been executed, during standby when no printing or the like is being performed. The non-discharge circulation may also be executed periodically.

[0090] As shown in FIG. 10 , in step S301, the control unit 19 opens the third valve 40. In step S302, the control unit 19 closes the second valve 38. In step S303, the control unit 19 pressurizes the second storage unit 35 to a second pressure P2. The control unit 19 pressurizes the second storage unit 35 to the second pressure P2 by driving the pressurizing unit 47. The second pressure P2 is a pressure lower than the meniscus breakdown pressure of the nozzle 22. The second pressure P2 is a pressure lower than the first pressure P1 used in the discharge circulation.

[0091] In step S304, control unit 19 determines whether or not second pressurization time T2 has elapsed since second storage unit 35 was pressurized in step S303. Second pressurization time T2 is the time required for second storage unit 35 to be pressurized up to second pressure P2.

[0092] Step S304 remains NO until the second pressurization time T2 has elapsed. The control unit 19 waits until the second pressurization time T2 has elapsed. When the second pressurization time T2 has elapsed, step S304 remains YES. The control unit 19 proceeds to step S305. In step S305, the control unit 19 opens the second valve 38. In step S306, the control unit 19 pressurizes the second storage unit 35 to the second pressure P2. In step S307, the control unit 19 determines whether a second predetermined time Tp2 has elapsed since the second valve 38 was opened in step S305. The second predetermined time Tp2 is the time required for the second storage unit 35 to be pressurized to the second pressure P2 with the second valve 38 open.

[0093] The second pressurization time T2 and the second predetermined time Tp2 may be set in advance or may be changed each time non-discharge circulation is performed. The second pressurization time T2 may be shorter than the first pressurization time T1 used in discharge circulation. The second predetermined time Tp2 may be longer than the first predetermined time Tp1 used in discharge circulation.

[0094] The control unit 19 may set the second pressurization time T2 and the second predetermined time Tp2 longer when the ambient temperature is a first temperature than when the ambient temperature is a second temperature higher than the first temperature. The control unit 19 may set the second pressurization time T2 and the second predetermined time Tp2 longer the lower the ambient temperature. The control unit 19 may use the number of seconds obtained by multiplying the ambient temperature by 0.5 and adding 37.5 to the number as either the second pressurization time T2 or the second predetermined time Tp2. The control unit 19 may use different second pressurization times T2 and second predetermined times Tp2 for each of a plurality of preset temperature ranges. In this case, the same value is used for the second pressurization time T2 even if the ambient temperatures are different but within the same temperature range. The same value is used for the second predetermined time Tp2 even if the ambient temperatures are different but within the same temperature range. Different values ​​are used for the second pressurization time T2 if the ambient temperatures are different but within different temperature ranges. If the environmental temperatures are different and fall within different temperature ranges, different values ​​are adopted as the second predetermined time Tp2.

[0095] The second pressurization time T2 is set so that the amount of liquid supplied from second storage unit 35 to supply flow path 37 during the second pressurization time T2 after pressurization of second storage unit 35 falls within a specified range. The second predetermined time Tp2 is set so that the amount of liquid supplied from second storage unit 35 to supply flow path 37 during the second predetermined time Tp2 after pressurization of second storage unit 35 falls within a specified range. The specified range of liquid amount is a range in which the amount of liquid required for non-discharge circulation can be supplied to supply flow path 37 and the amount of liquid stored in second storage unit 35 does not fall below a specified amount.

[0096] Step S307 remains NO until the second predetermined time Tp2 has elapsed. The control unit 19 waits until the second predetermined time Tp2 has elapsed. Once the second predetermined time Tp2 has elapsed, step S307 remains YES. The control unit 19 proceeds to step S308. In step S308, the control unit 19 stops pressurizing the second storage unit 35. In step S309, the control unit 19 opens the second storage unit 35 to the atmosphere. In step S310, the control unit 19 closes the second valve 38. In step S311, the control unit 19 closes the third valve 40. In step S312, the control unit 19 performs wiping using the maintenance member 91. In step S313, the control unit 19 executes the slight pressurization discharge routine and then ends the non-discharge circulation routine. At least two of steps S308, S309, S310, and S311 may be performed simultaneously.

[0097] As shown in FIG. 2, in non-discharge circulation, the control unit 19 pressurizes the second storage unit 35 and opens the second valve 38 while the recovery passageway 39 is open. As a result, the liquid flows from the second storage unit 35 into the supply passageway 37. The liquid is supplied to the liquid ejection head 23 through the supply passageway 37. The ejection of the liquid from the nozzle 22 is suppressed. The liquid is recovered from the liquid ejection head 23 into the recovery passageway 39. The liquid is returned to the first storage unit 33 through the recovery passageway 39.

[0098] In non-discharge circulation, the liquid stored in second reservoir 35 is agitated by flowing into supply flow path 37 from second reservoir 35. In non-discharge circulation, the liquid stored in first reservoir 33 is agitated by flowing into first reservoir 33 from recovery flow path 39.

[0099] <Filling circulation> The filling circulation routine will be described with reference to Figure 11. The filling circulation may be executed when first liquid level 66 in first reservoir 33 and second liquid level 70 in second reservoir 35 reach their standard positions after liquid storage portion 24 is initially attached to mounting portion 28.

[0100] 11, in step S401, the control unit 19 opens the third valve 40. In step S402, the control unit 19 closes the second valve 38. In step S403, the control unit 19 pressurizes the second storage unit 35 to a third pressure P3. The control unit 19 pressurizes the second storage unit 35 to the third pressure P3 by driving the pressurizing unit 47. The third pressure P3 is a pressure that is lower than the first pressure P1 used in the discharge circulation and higher than the second pressure P2 used in the non-discharge circulation.

[0101] In step S404, control unit 19 determines whether or not a third pressurization time T3 has elapsed since second storage unit 35 was pressurized in step S403. Third pressurization time T3 is the time required for second storage unit 35 to be pressurized up to third pressure P3.

[0102] Step S404 remains NO until the third pressurization time T3 has elapsed. The control unit 19 waits until the third pressurization time T3 has elapsed. When the third pressurization time T3 has elapsed, step S404 remains YES. The control unit 19 proceeds to step S405. In step S405, the control unit 19 opens the second valve 38. In step S406, the control unit 19 pressurizes the second storage unit 35 to a third pressure P3. In step S407, the control unit 19 determines whether a third predetermined time Tp3 has elapsed since the second valve 38 was opened in step S405. The third predetermined time Tp3 is the time required for the second storage unit 35 to be pressurized to the third pressure P3 with the second valve 38 open.

[0103] The third pressurization time T3 and the third predetermined time Tp3 may be preset or may be variable. The third pressurization time T3 may be shorter than the first pressurization time T1 used in the discharge circulation. The third pressurization time T3 may be the same as or different from the second pressurization time T2 used in the non-discharge circulation. The third predetermined time Tp3 may be longer than the first predetermined time Tp1 used in the discharge circulation. The third predetermined time Tp3 may be the same as or different from the second predetermined time Tp2 used in the non-discharge circulation.

[0104] The control unit 19 may set the third pressurization time T3 and the third predetermined time Tp3 longer when the ambient temperature is a first temperature than when the ambient temperature is a second temperature higher than the first temperature. The control unit 19 may set the third pressurization time T3 and the third predetermined time Tp3 longer the lower the ambient temperature. The control unit 19 may use different third pressurization times T3 and third predetermined times Tp3 for each of a plurality of preset temperature ranges. In this case, the same value is used for the third pressurization time T3 if the ambient temperatures are different but within the same temperature range. The same value is used for the third predetermined time Tp3 if the ambient temperatures are different but within the same temperature range. Different values ​​are used for the third pressurization time T3 if the ambient temperatures are different but within different temperature ranges. Different values ​​are used for the third predetermined time Tp3 if the ambient temperatures are different but within different temperature ranges.

[0105] The third pressurization time T3 is set so that the amount of liquid supplied from second storage portion 35 to supply flow path 37 during the period from when second storage portion 35 is pressurized until the third pressurization time T3 has elapsed falls within a specified range. The third predetermined time Tp3 is set so that the amount of liquid supplied from second storage portion 35 to supply flow path 37 during the period from when second storage portion 35 is pressurized until the third predetermined time Tp3 has elapsed falls within a specified range. The specified range of liquid amount is a range in which the amount of liquid required for filling and circulation can be supplied to supply flow path 37 and the amount of liquid stored in second storage portion 35 does not fall below a specified amount.

[0106] Step S407 remains NO until the third predetermined time Tp3 has elapsed. The control unit 19 waits until the third predetermined time Tp3 has elapsed. Once the third predetermined time Tp3 has elapsed, step S407 remains YES. The control unit 19 proceeds to step S408. In step S408, the control unit 19 stops pressurizing the second storage unit 35. In step S409, the control unit 19 opens the second storage unit 35 to the atmosphere. In step S410, the control unit 19 closes the second valve 38. In step S411, the control unit 19 closes the third valve 40. In step S412, the control unit 19 determines whether the liquid level recovery time has elapsed since the second valve 38 was closed in step S110. The liquid level recovery time is the time required for the second liquid level 70 of the liquid in the second storage unit 35 to reach the standard position.

[0107] Step S412 remains NO until the liquid level recovery time has elapsed. The control unit 19 waits until the liquid level recovery time has elapsed. Once the liquid level recovery time has elapsed, step S412 remains YES. The control unit 19 proceeds to step S413. In step S413, the control unit 19 determines whether the processing of steps S401 to S412 has been executed for the Nth time in this filling and circulation routine. The control unit 19 makes this determination using a preset third predetermined number of times n3 as the Nth time. The third predetermined number of times n3 may be 2.

[0108] Step S413 remains "NO" until the processing of steps S401 to S412 in the current circulation routine reaches the Nth time. The control unit 19 again performs the processing of steps S401 to S413. When the processing of steps S401 to S413 in the current filling circulation routine reaches the Nth time, step S413 remains "YES." The control unit 19 proceeds to step S414. In step S414, the control unit 19 performs wiping using the maintenance member 91. In step S415, the control unit 19 executes a slight pressure discharge routine and then ends the discharge circulation routine. Note that at least two of steps S408, S409, S410, and S411 may be performed simultaneously.

[0109] As shown in Fig. 2, during filling and circulation, the control unit 19 pressurizes the second storage unit 35 and opens the second valve 38 while the recovery passageway 39 is open. As a result, the liquid flows from the second storage unit 35 into the supply passageway 37. The liquid passes through the supply passageway 37 and is supplied to the liquid ejection head 23. A portion of the liquid supplied to the liquid ejection head 23 is discharged from the nozzle 22. The liquid is recovered from the liquid ejection head 23 into the recovery passageway 39. The liquid passes through the recovery passageway 39 and is returned to the first storage unit 33.

[0110] In the filling and circulation, the liquid flows into the supply flow path 37, the liquid ejection head 23, and the recovery flow path 39. As a result, the liquid is discharged from the nozzles 22 while the liquid is filled into the circulation path 11a.

[0111] <Operation of the embodiment> The operation of this embodiment will be described. In the discharge circulation, the control unit 19 closes the communication passage 34 using the first valve 36 and closes the supply flow path 37 using the second valve 38. The control unit 19 pressurizes the inside of the second storage unit 35 to a first pressure P1 using the pressurizing unit 47. The control unit 19 closes the communication passage 34 and the supply flow path 37, and after pressurizing the inside of the second storage unit 35 to the first pressure P1, opens the supply flow path 37 using the second valve 38. This allows the control unit 19 to perform discharge circulation in which the liquid is circulated in the circulation path 11a while the liquid is discharged from the nozzle 22.

[0112] In non-discharge circulation, the control unit 19 closes the communication passage 34 using the first valve 36 and closes the supply flow path 37 using the second valve 38. The control unit 19 pressurizes the inside of the second storage unit 35 to a second pressure P2 that is lower than the first pressure P1 using the pressurizing unit 47. The control unit 19 closes the communication passage 34 and the supply flow path 37, and after pressurizing the inside of the second storage unit 35 to the second pressure P2, opens the supply flow path 37 using the second valve 38. This allows the control unit 19 to perform non-discharge circulation in which the liquid is circulated inside the circulation path 11a without discharging the liquid from the nozzle 22.

[0113] In the filling circulation, the control unit 19 closes the communication passage 34 using the first valve 36 and closes the supply flow path 37 using the second valve 38. The control unit 19 pressurizes the inside of the second storage unit 35 to a third pressure P3, which is lower than the first pressure P1 and higher than the second pressure P2, using the pressurizing unit 47. The control unit 19 closes the communication passage 34 and the supply flow path 37, and after pressurizing the inside of the second storage unit 35 to the third pressure P3, opens the supply flow path 37 using the second valve 38. This allows the control unit 19 to perform filling circulation, in which the liquid is filled into the circulation path 11a while the liquid is discharged from the nozzle 22.

[0114] In the discharge circulation, non-discharge circulation, and fill circulation, as the pressurizing unit 47 pressurizes the second storage unit 35, the pressure in the second storage unit 35 becomes greater than the pressure in the first storage unit 33. This causes the first valve 36 to close the communication passage 34.

[0115] In the discharge circulation, non-discharge circulation, and fill circulation modes, the control unit 19 closes the supply flow path 37 using the second valve 38. The control unit 19 closes the communication passage 34 and the supply flow path 37, and pressurizes the inside of the second storage unit 35, and then opens the supply flow path 37 using the second valve 38. The control unit 19 pressurizes the inside of the second storage unit 35 with the second valve 38 closed. This allows the second storage unit 35 to be pressurized more quickly than when the second storage unit 35 is pressurized with the second valve 38 open.

[0116] In the discharge circulation, non-discharge circulation, and fill circulation modes, the control unit 19 pressurizes the inside of the second storage unit 35 using the pressurizing unit 47 after opening the supply flow path 37 using the second valve 38. This reduces the drop in pressure in the second storage unit 35 that occurs when the supply flow path 37 is opened by the second valve 38. In other words, the control unit 19 pressurizes the inside of the second storage unit 35 using the pressurizing unit 47 after opening the supply flow path 37 using the second valve 38 so as to reduce the drop in pressure in the second storage unit 35 that occurs when the supply flow path 37 is opened by the second valve 38.

[0117] In the discharge circulation, non-discharge circulation, and fill circulation modes, control unit 19 pressurizes second reservoir 35 and opens second valve 38 while recovery passageway 39 is open. As a result, the liquid flowing through recovery passageway 39 flows into first reservoir 33 via inlet 33a. The inflow of liquid from inlet 33a agitates the liquid stored in first reservoir 33.

[0118] In the discharge circulation, non-discharge circulation, and fill circulation modes, the control unit 19 closes the supply flow path 37 after a predetermined time has elapsed with the supply flow path 37 being opened by the second valve 38. The lower the ambient temperature, the higher the viscosity of the liquid. Therefore, the flow rate of the liquid flowing through the supply flow path 37 following the opening of the supply flow path 37 by the second valve 38 may vary depending on the ambient temperature. The control unit 19 lengthens the predetermined time when the ambient temperature detected by the temperature detection unit 80 is a first temperature compared to when the ambient temperature is a second temperature higher than the first temperature. Therefore, it is possible to prevent the flow rate of the liquid flowing through the circulation path 11a from increasing or decreasing due to changes in the ambient temperature.

[0119] <Effects of the embodiment> The effects of this embodiment will be described. (1) The control unit 19 can execute discharge circulation and non-discharge circulation. Multiple processes, such as discharge circulation and non-discharge circulation, can be performed using a common circulation path 11a. Therefore, compared to performing multiple processes using different paths, the complexity of the liquid flow path can be reduced. Furthermore, in discharge circulation and non-discharge circulation, the first valve 36 closes the communication path 34, the second valve 38 closes the supply flow path 37, and the pressurization unit 47 pressurizes the second reservoir 35 before the second valve 38 opens the supply flow path 37. Therefore, in discharge circulation and non-discharge circulation, the liquid can be circulated through the circulation path 11a earlier than when the second valve 38 opens the supply flow path 37 and then pressurizes the second reservoir 35. Therefore, the time required for multiple processes, such as discharge circulation and non-discharge circulation, can be reduced.

[0120] (2) The control unit 19 can execute the filling circulation. The discharge circulation and non-discharge circulation, as well as the filling circulation, which is a different process, can be performed using a common circulation path 11a. This further reduces the complexity of the path through which the liquid flows. Furthermore, in the filling circulation, the first valve 36 closes the communication path 34, the second valve 38 closes the supply flow path 37, and the pressurization unit 47 pressurizes the second storage unit 35 before the second valve 38 opens the supply flow path 37. Therefore, the liquid can be circulated through the circulation path 11a earlier in the filling circulation than when the second valve 38 opens the supply flow path 37 and then pressurizes the second storage unit 35. This reduces the time required for the filling circulation.

[0121] (3) After the second valve 38 opens the supply flow path 37, the control unit 19 causes the pressurizing unit 47 to pressurize the second storage unit 35 so as to reduce a pressure drop in the second storage unit 35 that accompanies the opening of the supply flow path 37 by the second valve 38. Therefore, compared to when the pressurizing unit 47 does not pressurize the second storage unit 35 after the second valve 38 opens the supply flow path 37, the pressure drop in the second storage unit 35 that accompanies the opening of the supply flow path 37 by the second valve 38 can be reduced. Therefore, the pressure in the second storage unit 35 that is necessary for circulating the liquid in the circulation path 11a and discharging the liquid from the nozzle 22 can be maintained.

[0122] (4) The first valve 36 is a one-way valve that closes the communication passage 34 when the pressurizing unit 47 pressurizes the second reservoir 35. This eliminates the need for a drive mechanism for driving the first valve 36. This makes it possible to prevent an increase in the number of parts mounted on the liquid ejection device 11.

[0123] (5) The lower the ambient temperature, the higher the viscosity of the liquid. Therefore, when the second valve 38 opens the supply flow path 37, the flow rate of the liquid flowing through the supply flow path 37 may vary depending on the ambient temperature. The control unit 19 closes the supply flow path 37 after a predetermined time has elapsed with the second valve 38 keeping the supply flow path 37 open. The control unit 19 sets the predetermined time to be longer when the ambient temperature detected by the temperature detection unit 80 is a first temperature than when the ambient temperature is a second temperature higher than the first temperature. Therefore, it is possible to prevent the flow rate of the liquid flowing through the circulation path 11a from increasing or decreasing with changes in the ambient temperature.

[0124] (6) First reservoir 33 is formed with inlet 33a through which the liquid in recovery passage 39 flows. Inlet 33a is located below the center of first reservoir 33. Therefore, the liquid flowing through recovery passage 39 flows into first reservoir 33 via inlet 33a. Because inlet 33a is located below the center of first reservoir 33, the inflow of liquid from inlet 33a agitates the liquid stored in first reservoir 33. Therefore, sedimentation in first reservoir 33 can be recovered.

[0125] (7) Control unit 19 can switch between closing and opening recovery passageway 39 using third valve 40. This makes it possible to switch between allowing and disallowing liquid to flow from recovery passageway 39 into first reservoir 33.

[0126] [Example of change] This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0127] The position where the supply port 35a in the second storage section 35 is formed is not limited to the second bottom 68b. For example, the supply port 35a may be formed in a side wall connecting the ceiling of the second storage section 35 and the second bottom 68b. The position where the supply port 35a in the second storage section 35 is formed is not limited to below the center of the second storage section 35. For example, the supply port 35a may be formed in the ceiling of the second storage section 35.

[0128] The position where inlet 33a is formed in first storage section 33 is not limited to first bottom 65b. For example, inlet 33a may be formed in a side wall connecting ceiling 65a and first bottom 65b of first storage section 33. The position where inlet 33a is formed in first storage section 33 is not limited to below the center of first storage section 33. For example, inlet 33a may be formed in ceiling 65a.

[0129] The slight pressurization and discharge may be achieved by using the spring 54 to pressurize the liquid in the liquid chamber 41 by pushing the flexible member 42. In this case, the control unit 19 depressurizes the air chamber 53 to increase the volume of the liquid chamber 41, and then opens the air chamber 53 to the atmosphere. When the air chamber 53 reaches atmospheric pressure, the spring 54 presses the liquid in the liquid chamber 41, causing the liquid to be discharged from the liquid ejection head 23.

[0130] The control unit 19 may omit the wiping process in at least some of the discharge circulation, non-discharge circulation, and filling circulation. The control unit 19 may omit the slight pressurization discharge process in at least some of the discharge circulation, non-discharge circulation, and filling circulation.

[0131] In the discharge circulation, the control unit 19 may omit at least one of step S112 and step S113. In the filling circulation, the control unit 19 may omit at least one of step S412 and step S413.

[0132] The control unit 19 may use a preset value for at least one of the first pressurization time T1 in the discharge circulation, the second pressurization time T2 in the non-discharge circulation, and the third pressurization time T3 in the fill circulation.

[0133] The control unit 19 may use a preset value for at least one of the first predetermined time Tp1 in the discharge circulation mode, the second predetermined time Tp2 in the non-discharge circulation mode, and the third predetermined time Tp3 in the fill circulation mode. The temperature detection unit 80 may be omitted from the liquid discharger 11.

[0134] The third valve 40 may be omitted from the liquid ejection device 11. In the discharge circulation, non-discharge circulation, and filling circulation modes, the control unit 19 may omit processing related to the third valve 40. The recovery flow path 39 may be always open.

[0135] The control unit 19 may omit the processes of steps S106 and S107 in the discharge circulation mode. The control unit 19 may omit the processes of steps S306 and S307 in the non-discharge circulation mode. The control unit 19 may omit the processes of steps S406 and S407 in the fill circulation mode.

[0136] Instead of the filling circulation routine shown in FIG. 11, the control unit 19 may perform filling circulation in which the liquid is filled into the supply flow path 37 using a path different from the circulation path 11a. The first valve 36 may be a control valve whose opening and closing can be controlled by the control unit 19. The control unit 19 may close the first valve 36 before pressurizing the inside of the second reservoir 35, thereby blocking the communication passage 34.

[0137] The liquid ejection head 23 may have a plurality of pressure chambers that individually communicate with the plurality of nozzles 22, a common liquid chamber that communicates with the plurality of pressure chambers, and a filter chamber that houses a filter. The first connection portion 44 and the second connection portion 45 are connected to at least one of the pressure chambers, the common liquid chamber, and the filter chamber. For example, when the first connection portion 44 and the second connection portion 45 are connected to the filter chamber, the liquid ejection device 11 can perform exhaust circulation to collect air bubbles captured by the filter together with the liquid into the first reservoir 33.

[0138] Control unit 19 may reduce the pressure inside first storage unit 33 when causing liquid to flow from recovery flow path 39 into first storage unit 33. For example, atmosphere open path 50 may be connected to air flow path 55. By driving pressurizer 47 in the forward direction, the pressure inside second storage unit 35 may be increased and the pressure inside first storage unit 33 may be reduced via air flow path 55 and atmosphere open path 50.

[0139] The first reservoir 33 and the second reservoir 35 may be integrally formed. The flexible member 42 may be formed of a rubber membrane, an elastomer membrane, a film, or the like. The liquid chamber 41 may be provided in the supply flow path 37. The pressurizing mechanism 57 may pressurize the liquid chamber 41 provided in the supply flow path 37.

[0140] The pressurizing unit 47 may be a diaphragm pump, a piston pump, a gear pump, or the like. The inlet portion 60 and the outlet portion 30 may have multiple flow paths. For example, one flow path may allow liquid to flow from the liquid storage portion 24 to the first reservoir 33, and another flow path may allow air to flow from the first reservoir 33 to the liquid storage portion 24.

[0141] The liquid ejection head 23 may eject liquid in a horizontal position with the nozzle surface 21 horizontal to print on the medium 12. The liquid ejection head 23 may be provided so that its position can be changed between a horizontal position and an inclined position.

[0142] The liquid discharger 11 may be provided with an air release path that opens the second reservoir 35 to the atmosphere, separate from the pressurized flow path 51 . The liquid ejection device 11 may be a liquid ejection device that ejects or discharges liquids other than ink. The liquid ejected as minute droplets from the liquid ejection device may be in the form of granules, tears, or strings. The liquid referred to here may be any material that can be ejected from the liquid ejection device. For example, the liquid may be in any liquid phase, including fluids such as high or low viscosity liquids, sols, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals, and metal melts. The liquid may refer not only to a single state of matter, but also to solid functional material particles, such as pigments and metal particles, dissolved, dispersed, or mixed in a solvent. Typical examples of liquids include inks and liquid crystals, as described in the above embodiments. Here, ink encompasses various liquid compositions, such as general water-based inks and oil-based inks, as well as gel inks and hot-melt inks. Specific examples of liquid ejection devices include devices that eject liquids containing dispersed or dissolved materials such as electrode materials and color materials used in the manufacture of liquid crystal displays, electroluminescent displays, surface-emitting displays, and color filters. The liquid ejection device may be a device that ejects bioorganic materials used in biochip manufacture, a device used as a precision pipette to eject sample liquids, a textile printing device, a microdispenser, or the like. The liquid ejection device may be a device that ejects lubricating oil with pinpoint accuracy onto precision machinery such as watches and cameras, or a device that ejects transparent resin liquids such as ultraviolet-curing resins onto substrates to form micro-hemispherical lenses, optical lenses, and the like used in optical communication elements. The liquid ejection device may also be a device that ejects etching liquids such as acids or alkalis to etch substrates, etc.

[0143] [Note] The technical concepts and effects that can be understood from the above-described embodiment and modified examples will be described below.

[0144] (A) A liquid ejection device comprising: a liquid ejection head capable of ejecting liquid from a nozzle; a first reservoir for storing the liquid; a second reservoir communicating with the first reservoir via a communication passage and receiving the liquid from the first reservoir; a supply flow path for supplying the liquid from the second reservoir to the liquid ejection head; a recovery flow path for recovering the liquid from the liquid ejection head to the first reservoir; a first valve provided in the communication passage and capable of opening and closing the communication passage; a second valve provided in the supply flow path and capable of opening and closing the supply flow path; a pressurizing unit for pressurizing the second reservoir; and a control unit, wherein the supply flow path, the liquid ejection head, and the recovery flow path constitute a circulation path for circulating the liquid, and the control unit controls the It is possible to perform a discharge circulation in which the liquid is circulated in the circulation path while discharging the liquid from the nozzle by closing the communicating passage with the first valve and the supply flow path with the second valve, and the pressure inside the second storage section is pressurized to a first pressure by the pressurizing unit, and then the supply flow path is opened by the second valve; and a non-discharge circulation in which the liquid is circulated in the circulation path without discharging the liquid from the nozzle by closing the communicating passage with the first valve and the supply flow path with the second valve, and then the pressure inside the second storage section is pressurized to a second pressure lower than the first pressure by the pressurizing unit, and then the supply flow path is opened by the second valve.

[0145] According to this configuration, multiple processes, such as discharge circulation and non-discharge circulation, can be performed using a common circulation path. Therefore, compared to performing multiple processes using different paths, the complexity of the paths through which the liquid flows can be suppressed. Furthermore, according to this configuration, in discharge circulation and non-discharge circulation, the first valve closes the communication path, the second valve closes the supply flow path, and the pressurization unit pressurizes the second reservoir before the second valve opens the supply flow path. Therefore, in discharge circulation and non-discharge circulation, the liquid can be circulated through the circulation path earlier than when the second valve opens the supply flow path and then pressurizes the second reservoir. Therefore, the time required for multiple processes, such as discharge circulation and non-discharge circulation, can be shortened.

[0146] (B) In the liquid ejection device, the control unit closes the connecting passage with the first valve and closes the supply flow path with the second valve, and pressurizes the second storage section to a third pressure that is smaller than the first pressure and larger than the second pressure with the pressurizing unit, and then opens the supply flow path with the second valve, thereby performing a filling circulation in which the liquid is filled into the circulation path while the liquid is discharged from the nozzle.

[0147] According to this configuration, discharge circulation, non-discharge circulation, and filling circulation, which is a different process, can be performed using a common circulation path. Therefore, the complexity of the path through which the liquid flows can be further reduced. Furthermore, according to this configuration, in filling circulation, the first valve closes the communication passage, the second valve closes the supply passage, and the pressurization unit pressurizes the second reservoir before the second valve opens the supply passage. Therefore, compared to when the second valve opens the supply passage and then pressurizes the second reservoir, the liquid can be circulated through the circulation path earlier in filling circulation. Therefore, the time required for filling circulation can be shortened.

[0148] (C) In the liquid ejection device, the control unit pressurizes the second storage section using the pressurizing unit after opening the supply flow path using the second valve so that a decrease in pressure in the second storage section due to the opening of the supply flow path by the second valve is reduced.

[0149] With this configuration, the pressure drop in the second reservoir due to the opening of the supply flow path by the second valve can be reduced compared to when the pressurizing unit does not pressurize the second reservoir after the opening of the supply flow path by the second valve, and therefore the pressure in the second reservoir necessary for circulating the liquid in the circulation path and discharging the liquid from the nozzle can be maintained.

[0150] (D) In ​​the liquid ejection device, the first valve is a one-way valve that closes the communication passage as the pressurizing unit pressurizes the second storage unit. According to this configuration, a drive mechanism for driving the first valve is not required, and therefore an increase in the number of parts mounted on the liquid ejection device can be suppressed.

[0151] (E) The liquid ejection device further includes a temperature detection unit that detects an environmental temperature, which is the temperature of the environment in which the liquid ejection device is used, and the control unit closes the supply flow path after a predetermined time has elapsed while the supply flow path is opened by the second valve, and makes the predetermined time longer when the environmental temperature detected by the temperature detection unit is a first temperature than when it is a second temperature higher than the first temperature.

[0152] The lower the ambient temperature, the higher the viscosity of the liquid. Therefore, when the second valve opens the supply flow path, the flow rate of the liquid flowing through the supply flow path may vary depending on the ambient temperature. With this configuration, the predetermined time is longer when the ambient temperature is the first temperature than when the ambient temperature is the second temperature, which is higher than the first temperature. Therefore, it is possible to prevent the flow rate of the liquid flowing through the circulation path from increasing or decreasing due to changes in the ambient temperature.

[0153] (F) In the liquid ejection device, an inlet through which the liquid in the recovery channel flows is formed in the first reservoir, and the inlet is located below the center of the first reservoir. With this configuration, the liquid flowing through the recovery channel flows into the first reservoir through the inlet. Because the inlet is located below the center of the first reservoir, the liquid flowing in from the inlet agitates the liquid stored in the first reservoir. This allows the sedimentation in the first reservoir to be recovered.

[0154] (G) The liquid ejection device further comprises a third valve provided in the recovery passageway and capable of opening and closing the recovery passageway, and the control unit is capable of switching between closing and opening the recovery passageway using the third valve.

[0155] With this configuration, it is possible to switch between allowing and not allowing the liquid to flow from the recovery channel into the first reservoir. (H) A method for controlling a liquid ejection device, the method comprising: a liquid ejection head capable of ejecting liquid from a nozzle; a first reservoir for storing the liquid; a second reservoir communicating with the first reservoir via a communication path and receiving the liquid from the first reservoir; a supply flow path for supplying the liquid from the second reservoir to the liquid ejection head; a recovery flow path for recovering the liquid from the liquid ejection head to the first reservoir; a first valve provided in the communication path and capable of opening and closing the communication path; a second valve provided in the supply flow path and capable of opening and closing the supply flow path; and a pressurizing unit for pressurizing the second reservoir, wherein the supply flow path, the liquid ejection head, and the recovery flow path constitute a circulation path for circulating the liquid, When performing discharge circulation in which the liquid is circulated within the circulation path while being discharged, the first valve closes the connecting passage and the second valve closes the supply flow path, and the pressure unit pressurizes the second storage section to a first pressure that is greater than the meniscus breakdown pressure of the nozzle, and then the second valve opens the supply flow path; when performing non-discharge circulation in which the liquid is circulated within the circulation path without being discharged from the nozzle, the first valve closes the connecting passage and the second valve closes the supply flow path, and the pressure unit pressurizes the second storage section to a second pressure that is less than the meniscus breakdown pressure, and then the second valve opens the supply flow path.

[0156] According to this method, multiple processes, such as discharge circulation and non-discharge circulation, can be performed using a common circulation path. Therefore, compared to performing multiple processes using different paths, the complexity of the paths through which the liquid flows can be reduced. Furthermore, according to this method, in the discharge circulation and non-discharge circulation, the first valve closes the communication path, the second valve closes the supply flow path, and the pressurization unit pressurizes the second reservoir before the second valve opens the supply flow path. Therefore, in the discharge circulation and non-discharge circulation, the liquid can be circulated through the circulation path earlier than when the second valve opens the supply flow path and then pressurizes the second reservoir. Therefore, the time required for multiple processes, such as the discharge circulation and non-discharge circulation, can be shortened.

[0157] (I) In a method for controlling a liquid ejection device, the liquid ejection device further includes a temperature detection unit that detects an environmental temperature, which is the temperature of the environment in which the liquid ejection device is used, and closes the supply flow path after a predetermined time has elapsed with the supply flow path being opened by the second valve, and the predetermined time is longer when the environmental temperature detected by the temperature detection unit is a first temperature than when it is a second temperature higher than the first temperature.

[0158] The lower the ambient temperature, the higher the viscosity of the liquid. Therefore, when the second valve opens the supply flow path, the flow rate of the liquid flowing through the supply flow path may vary depending on the ambient temperature. According to this method, the predetermined time is set longer when the ambient temperature is a first temperature than when the ambient temperature is a second temperature higher than the first temperature. Therefore, it is possible to prevent the flow rate of the liquid flowing through the circulation path from increasing or decreasing due to changes in the ambient temperature. [Explanation of symbols]

[0159] P1...first pressure, P2...second pressure, P3...third pressure, 11...liquid ejection device, 11a...circulation path, 19...control unit, 22...nozzle, 23...liquid ejection head, 33...first storage section, 33a...inlet, 34...communicating passage, 35...second storage section, 36...first valve, 37...supply flow path, 38...second valve, 39...recovery flow path, 40...third valve, 47...pressurizing section, 80...temperature detection section.

Claims

1. a liquid ejection head capable of ejecting liquid from a nozzle; a first reservoir that stores the liquid; a second reservoir communicating with the first reservoir via a communication passage and receiving the liquid from the first reservoir; a supply flow path that supplies the liquid from the second reservoir to the liquid ejection head; a recovery flow path that recovers the liquid from the liquid ejection head to the first reservoir; a first valve provided in the communication passage and capable of opening and closing the communication passage; a second valve provided in the supply flow path and capable of opening and closing the supply flow path; a pressurizing unit that pressurizes the second storage unit; a control unit, the supply flow path, the liquid ejection head, and the recovery flow path form a circulation path that can circulate the liquid; The control unit a discharge circulation in which the liquid is circulated in the circulation path while being discharged from the nozzle by closing the communication passage with the first valve and closing the supply flow path with the second valve, and the pressure inside the second storage section is increased to a first pressure by the pressurizing section, and then the supply flow path is opened with the second valve; a non-discharge circulation in which the liquid is circulated in the circulation path without being discharged from the nozzle by closing the communication passage with the first valve and closing the supply flow path with the second valve, and pressurizing the inside of the second storage section to a second pressure lower than the first pressure with the pressurizing unit, and then opening the supply flow path with the second valve; A liquid ejection device characterized by being capable of executing the above.

2. The liquid ejection device described in claim 1, characterized in that the control unit is capable of performing a filling circulation in which the liquid is filled into the circulation path while the liquid is discharged from the nozzle by closing the connecting passage with the first valve and closing the supply flow path with the second valve, and by pressurizing the second storage unit to a third pressure that is smaller than the first pressure and larger than the second pressure with the pressurizing unit, and then opening the supply flow path with the second valve.

3. The liquid ejection device described in claim 1 or claim 2, characterized in that the control unit pressurizes the second storage section using the pressurizing unit after opening the supply flow path by the second valve so as to reduce the decrease in pressure in the second storage section due to the opening of the supply flow path by the second valve.

4. 4. The liquid ejection device according to claim 1, wherein the first valve is a one-way valve that closes the communication passage in response to pressurization of the second reservoir by the pressurizing unit.

5. a temperature detection unit for detecting an environmental temperature in which the liquid ejection device is used; A liquid ejection device described in any one of claims 1 to 4, characterized in that the control unit closes the supply flow path after a predetermined time has elapsed while the second valve has opened the supply flow path, and the predetermined time is longer when the environmental temperature detected by the temperature detection unit is a first temperature than when the environmental temperature is a second temperature higher than the first temperature.

6. an inlet through which the liquid in the recovery channel flows is formed in the first reservoir; 6. The liquid ejection device according to claim 1, wherein the inlet is located below the center of the first reservoir.

7. a third valve provided in the recovery passage and capable of opening and closing the recovery passage; 7. The liquid ejection device according to claim 1, wherein the control unit is capable of switching between closing and opening the recovery passageway by the third valve.

8. a liquid ejection head capable of ejecting liquid from a nozzle; a first reservoir that stores the liquid; a second reservoir communicating with the first reservoir via a communication passage and receiving the liquid from the first reservoir; a supply flow path that supplies the liquid from the second reservoir to the liquid ejection head; a recovery flow path that recovers the liquid from the liquid ejection head to the first reservoir; a first valve provided in the communication passage and capable of opening and closing the communication passage; a second valve provided in the supply flow path and capable of opening and closing the supply flow path; a pressurizing unit that pressurizes the second storage unit, a control method for a liquid ejection device, wherein the supply flow path, the liquid ejection head, and the recovery flow path constitute a circulation path that can circulate the liquid, When performing discharge circulation in which the liquid is circulated in the circulation path while being discharged from the nozzle, the first valve closes the communication passage and the second valve closes the supply flow path, and the pressure in the second reservoir is pressurized by the pressurizing unit to a first pressure higher than the meniscus breakdown pressure of the nozzle, and then the second valve opens the supply flow path, A control method for a liquid ejection device, characterized in that when performing non-discharge circulation in which the liquid is circulated within the circulation path without being discharged from the nozzle, the first valve closes the connecting passage and the second valve closes the supply flow path, and the pressure unit pressurizes the second storage unit to a second pressure that is smaller than the meniscus breakdown pressure, and then the second valve opens the supply flow path.

9. the liquid ejection device further includes a temperature detection unit that detects an environmental temperature, which is the temperature of an environment in which the liquid ejection device is used; A control method for a liquid ejection device as described in claim 8, characterized in that the supply flow path is closed after a predetermined time has elapsed while the supply flow path is opened by the second valve, and the predetermined time is longer when the environmental temperature detected by the temperature detection unit is a first temperature than when it is a second temperature higher than the first temperature.

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