JP7501188B2 - LIQUID EJECTION APPARATUS AND METHOD FOR CONTROLLING LIQUID EJECTION APPARATUS - Google Patents

Description

The present invention relates to a liquid ejection device such as a printer, and a method for controlling a liquid ejection device.

For example, as disclosed in Patent Document 1, there is a recording device that is an example of a liquid ejection device that prints by ejecting ink, which is an example of a liquid, from nozzles formed in a recording head, which is an example of a liquid ejection head. The recording device sucks ink from the nozzles by operating a suction pump with a cap placed on the recording head.

JP 2014-024189 A

Suction cleaning, which uses suction to drain liquid, creates a negative pressure inside the liquid ejection head even after the suction cleaning is complete. As a result, the recording head draws in liquid that has adhered to the nozzle surface where the nozzles are located through the nozzles as a result of suction, and there is a risk that the liquids will mix together inside the recording head.

A liquid ejection device that solves the above problem includes a liquid ejection head that ejects liquid from a nozzle provided on a nozzle surface, a first storage section that communicates with a liquid storage section that stores the liquid and whose liquid level fluctuates within a range lower than the nozzle surface, a second storage section that communicates with the first storage section via a communication passage and to which the liquid is supplied from the first storage section due to a head difference, a supply flow passage that supplies the liquid from the second storage section to the liquid ejection head, a pressure variable mechanism that reduces pressure in the first storage section and pressurizes the second storage section, and a first valve that can close the communication passage when the pressure variable mechanism pressurizes the second storage section.

A method for controlling a liquid ejection device that solves the above problem is a method for controlling a liquid ejection device that includes a liquid ejection head that ejects liquid from a nozzle provided on a nozzle surface, a first storage section that communicates with a liquid storage section that stores the liquid, a second storage section that communicates with the first storage section via a communication passage, a supply flow path that supplies the liquid from the second storage section to the liquid ejection head, a first valve that can open and close the communication passage, and a pressure variable mechanism that reduces pressure in the first storage section and increases pressure in the second storage section, and the first valve closes the communication passage. the pressure in the first storage unit is reduced by the pressure variable mechanism to supply the liquid from the liquid storage unit to the first storage unit; the first valve opens the communication passage and releases the reduced pressure in the first storage unit by the pressure variable mechanism to supply the liquid from the first storage unit to the second storage unit at a head difference; the first valve closes the communication passage again; and the pressure variable mechanism pressurizes the second storage unit to discharge the liquid from the nozzle.

FIG. 1 is a perspective view of an embodiment of a liquid ejection device. 2 is a schematic diagram of a supply mechanism and a drive mechanism included in the liquid ejection device. 13 is a flow chart showing a full filling routine. 11 is a flow chart showing a liquid circulation routine. 4 is a flowchart showing a printing routine. 4 is a flowchart showing a pressurization and discharge routine. 4 is a flowchart showing an accumulated pressure discharge routine. 5 is a flowchart showing a slight pressurization and discharge routine. 11 is a flowchart showing a head replacement routine.

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

In the drawings, the liquid ejection device 11 is placed on a horizontal plane, with the direction of gravity indicated by the Z axis, and the directions along the horizontal plane indicated by the X and Y axes. The X, Y, and Z axes are mutually perpendicular.

As shown in FIG. 1, the liquid ejection device 11 may include a medium storage unit 13 capable of storing a medium 12, a stacker 14 for receiving the printed medium 12, and an operation unit 15, such as a touch panel, for operating the liquid ejection device 11. The liquid ejection device 11 may also include an image reading unit 16 for reading an image of a document, and an automatic feed unit 17 for feeding the document to the image reading unit 16.

The liquid ejection device 11 includes a control unit 19 that controls various operations executed by the liquid ejection device 11. The control unit 19 is composed of, for example, a processing circuit including a computer and a memory, and performs control according to a program stored in the memory.

As shown in FIG. 2, the liquid ejection device 11 includes a liquid ejection head 23 that ejects liquid from nozzles 22 provided on the nozzle surface 21, a supply mechanism 25 that supplies the liquid contained in the liquid storage section 24 to the liquid ejection head 23, and a drive mechanism 26 that drives the supply mechanism 25. The liquid ejection device 11 may include multiple supply mechanisms 25. The multiple 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 multiple colors of ink supplied by the multiple supply mechanisms 25. One drive mechanism 26 may drive the multiple supply mechanisms 25 collectively. The liquid ejection device 11 may include multiple drive mechanisms 26 that drive the multiple supply mechanisms 25 individually.

The liquid ejection head 23 may be detachably attached to the main body of the liquid ejection device 11. The liquid ejection head 23 is 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 in this embodiment is a line type that is installed across the width of the medium 12. The liquid ejection head 23 may also be configured as a serial type that prints while moving in the width direction of the medium 12.

The supply mechanism 25 may include an attachment portion 28 to which the liquid storage portion 24 is detachably attached, an introduction flow path 29 capable of introducing liquid from the liquid storage portion 24 attached to the attachment portion 28, and an introduction valve 30 capable of opening and closing the introduction flow path 29. The liquid storage portion 24 before being attached to the attachment portion 28 may contain an amount of liquid greater than the amount of liquid that the supply mechanism 25 can hold. The liquid storage portion 24 is connected to the upstream end of the introduction flow path 29 by being attached to the attachment portion 28. The introduction valve 30 is configured with a check valve that allows the flow of liquid from the liquid storage portion 24 to the first storage portion 33 and limits the flow of liquid from the first storage portion 33 to the liquid storage portion 24.

The supply mechanism 25 includes a first storage section 33 that stores liquid supplied from a liquid storage section 24 that stores liquid, a communication passage 34 whose upstream end is connected to the first storage section 33, and a second storage section 35 whose downstream end is connected to the communication passage 34. The first storage section 33 in this embodiment is connected to the downstream end of the introduction flow path 29 and communicates with the liquid storage section 24 via the introduction flow path 29. The second storage section 35 communicates with the first storage section 33 via the communication passage 34. The supply mechanism 25 includes a first valve 36 that can open and close the communication passage 34, and a supply flow path 37 that supplies liquid from the second storage section 35 to the liquid ejection head 23. The supply mechanism 25 may include a second valve 38 provided in a supply flow path 37 between the second storage section 35 and the liquid ejection head 23, a recovery flow path 39 that recovers liquid from the liquid ejection head 23 to the first storage section 33, a third valve 40 that can open and close the recovery flow path 39, and a liquid chamber 41 provided in the recovery flow path 39.

The liquid chamber 41 is provided in the recovery flow path 39 between the liquid ejection head 23 and the third valve 40. A portion of the liquid chamber 41 is made of a flexible member 42, and the volume of the liquid chamber 41 changes when the flexible member 42 deforms.

The liquid ejection head 23 may have a first connection part 44 to which the recovery flow passage 39 is connected, and a second connection part 45 to which the supply flow passage 37 is connected. The recovery flow passage 39 has an upstream end connected to the first connection part 44 and a downstream end connected to the first storage part 33. The supply flow passage 37 has an upstream end connected to the second storage part 35 and a downstream end connected to the second connection part 45. In the inclined position, the first connection part 44 between the liquid ejection head 23 and the recovery flow passage 39 may be positioned higher than the second connection part 45 between the liquid ejection head 23 and the supply flow passage 37.

The drive mechanism 26 includes a pressure variable mechanism 47 that reduces the pressure inside the first storage section 33 and pressurizes the second storage section 35. The drive mechanism 26 may include a pressure reduction flow path 48 that connects the first storage section 33 to the pressure variable mechanism 47, and a pressure sensor 49 that can detect the pressure inside the pressure reduction flow path 48. The drive mechanism 26 may include an atmosphere release path 50 that is connected to the first storage section 33, and a pressurized flow path 51 that connects the second storage section 35 to the pressure variable mechanism 47.

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 of the liquid in the recovery flow path 39 and the liquid ejection head 23.

The pressure variable mechanism 47 is, for example, a tube pump that pumps air by rotating a roller while squeezing a tube. The pressure variable mechanism 47 has a tube (not shown) connected to the reduced pressure flow path 48 and the air flow path 55 at one end and to the pressurized flow path 51 at the other end. When the pressure variable mechanism 47 is driven in the forward direction, it sends air taken in from the reduced pressure flow path 48 and the air flow path 55 to the pressurized flow path 51. When the pressure variable mechanism 47 is driven in the reverse direction, it sends air taken in from the pressurized flow path 51 to the reduced pressure flow path 48 and the air flow path 55.

In this embodiment, the pressure variable mechanism 47, the air chamber 53, and the air flow path 55 that connects the pressure variable mechanism 47 and the air chamber 53 constitute the pressurizing mechanism 57, and the liquid chamber 41 is added to the pressurizing mechanism 57 to constitute the micro-pressurizing unit 58. The micro-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 micro-pressurizing unit 58 is provided in the recovery flow path 39 between the liquid ejection head 23 and the third valve 40, and pressurizes the liquid in the recovery flow path 39.

Next, the first storage section 33 will be described.
The first storage section 33 may have a pressure reduction chamber 60 to which the pressure reduction flow path 48 is connected, and a float valve 61 capable of opening and closing the pressure reduction flow path 48. The first storage section 33 may have a first storage chamber 62 for storing liquid, a liquid amount sensor 63 for detecting the amount of liquid stored in the first storage chamber 62, and a first gas-liquid separation membrane 64 for separating the first storage chamber 62 from the drive mechanism 26. The first gas-liquid separation membrane 64 is a membrane having a property of passing gas but not passing liquid. For example, the first gas-liquid separation membrane 64 may be provided in the first storage chamber 62 so as to separate the first storage chamber 62 from the atmospheric open path 50. The first gas-liquid separation membrane 64 may be provided in the pressure reduction chamber 60 so as to separate the first storage chamber 62 from the pressure reduction flow path 48. The first storage section 33 may be provided with a seal member 65 capable of sealing between the pressure reduction chamber 60 and the float valve 61.

The float valve 61 moves in accordance with the movement of the first liquid level 66 in the first storage section 33. When the height of the first liquid level 66 reaches a predetermined height, the float valve 61 comes into contact with the seal member 65 and closes the reduced pressure chamber 60. In other words, the float valve 61 of this embodiment closes the reduced pressure flow path 48 by separating the reduced pressure chamber 60 from the first storage chamber 62.

In this embodiment, the position of the first liquid level 66 when the float valve 61 closes the pressure reduction passage 48 is called the standard position. The standard position is a position lower than the nozzle surface 21. The first liquid level 66 fluctuates within a range lower than the nozzle surface 21.

Specifically, when the first liquid level 66 is located below the standard position, the float valve 61 moves away from the seal member 65, and the first storage chamber 62 communicates with the reduced pressure chamber 60. When the pressure variable mechanism 47 reduces the pressure inside the reduced pressure chamber 60, the first storage section 33 is also reduced in pressure, and liquid is supplied from the liquid storage section 24 to the first storage section 33. The first liquid level 66 rises by the amount of the supplied liquid. When the first liquid level 66 reaches the standard position, the float valve 61 closes the reduced pressure flow path 48. This stops the reduction in pressure inside the first storage chamber 62, and stops the flow of liquid from the liquid storage section 24 to the first storage section 33.

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 the float valve 61 connects the reduced pressure chamber 60 to the first storage section 62, liquid is supplied from the liquid storage section 24 to the first storage section 33. Therefore, the first liquid level 66 moves below the standard position.

When the liquid contained in the liquid storage section 24 runs out, the first liquid level 66 cannot rise to the standard position. The liquid level sensor 63 may detect that the first liquid level 66 is at the standard position, that the first liquid level 66 is at a refill position below the standard position, or that 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 storage section 33 stores the maximum amount of liquid. The refill position is a position that serves as a guide for refilling the first storage section 33 with liquid from the liquid storage section 24. When the first liquid level 66 does not rise to the standard position even when the pressure inside the first storage section 33 is reduced, the control section 19 may determine that the liquid storage section 24 has run out and instruct the user to replace the liquid storage section 24 or refill the liquid storage section 24 with liquid.

In this embodiment, the standard position is located in the first storage chamber 62 above the position where the downstream end of the recovery passage 39 is connected. Therefore, when the first liquid level 66 is in the standard position, the liquid in the first storage section 33 can be supplied to the liquid ejection head 23 via the recovery passage 39.

Next, the second storage section 35 will be described.
The second storage section 35 may have a second storage chamber 68 that stores a liquid, and a second gas-liquid separation membrane 69 that separates the second storage chamber 68 from the pressurized flow path 51. Like the first gas-liquid separation membrane 64, the second gas-liquid separation membrane 69 is a membrane that has the property of passing gas but not liquid.

The second storage section 35 is supplied with liquid from the first storage section 33 by the head difference. The first valve 36 may be configured with a check valve that allows the flow of liquid from the first storage section 33 to the second storage section 35 and limits the flow of liquid from the second storage section 35 to the first storage section 33. When the first storage chamber 62 and the second storage chamber 68 are at atmospheric pressure, the 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 fluctuates in a range lower than the nozzle surface 21. The liquid in the liquid ejection head 23 is maintained at negative pressure by the head difference with 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.

The first valve 36 closes the communication passage 34 when the pressure in the second storage section 35 is greater than the pressure in the first storage section 33. Therefore, the first valve 36 closes the communication passage 34 when the second storage section 35 is pressurized by the pressure variable mechanism 47. The first valve 36 closes the communication passage 34 when the first storage section 33 is depressurized by the pressure variable mechanism 47. The second valve 38 and the third valve 40 are controlled to open and close by the control section 19. The second valve 38 is provided so as to be able to open and close the supply flow path 37 when pressurized by the pressure variable mechanism 47.

The drive mechanism 26 includes a thin tube section 72 that branches off from the pressurized flow path 51, and a first selection valve 73a to a ninth selection valve 73i 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 relative to the flow of air.

When the first selection valve 73a is opened, it connects the reduced pressure flow path 48 and the air flow path 55 to the atmosphere. When the second selection valve 73b is opened, it connects the reduced pressure flow path 48 and 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 pressure variable mechanism 47 to the air chamber 53.

The fourth selection valve 73d opens the decompression flow path 48 by opening, and connects the pressure variable mechanism 47 to the decompression chamber 60. The fifth selection valve 73e connects the pressurized flow path 51 to the pressure sensor 49 by opening. The sixth selection valve 73f connects the pressurized flow path 51 to the atmosphere by opening. The seventh selection valve 73g opens the atmosphere release path 50 by opening, and connects the first storage chamber 62 to the atmosphere. The eighth selection valve 73h opens the pressurized flow path 51 by opening, and connects the pressure variable mechanism 47 to the second storage chamber 68. The ninth selection valve 73i connects the pressurized flow path 51 to the thin tube section 72 by opening, and connects the pressurized flow path 51 to the atmosphere via the thin tube section 72.

When changing the pressure in the air chamber 53, the drive mechanism 26 opens the second selection valve 73b, the third selection valve 73c, and the sixth selection valve 73f, and closes the other selection valves. When the pressure variable mechanism 47 is driven in the forward direction in this state, the air in the air chamber 53 is discharged through the air flow path 55 and the pressurized flow path 51, and the pressure in the air chamber 53 decreases. When the pressure variable mechanism 47 is driven in the reverse direction in this state, air is sent into the air chamber 53 through the pressurized flow path 51 and the air flow path 55, and the pressure in the air chamber 53 increases. At this time, the pressure sensor 49 may detect the pressure in the air flow path 55 and the air chamber 53. The control unit 19 may control the drive of the pressure variable mechanism 47 based on the detection result of the pressure sensor 49.

When the first storage section 33 is opened to the atmosphere, the drive mechanism 26 opens the seventh selection valve 73g and stops driving the pressure variable mechanism 47. The first storage chamber 62 is connected to the atmosphere via the atmosphere release path 50 and becomes at atmospheric pressure.

When reducing the pressure inside the first reservoir 33, the drive mechanism 26 opens the second selection valve 73b, the fourth selection valve 73d, and the sixth selection valve 73f, and closes the other selection valves. When the pressure variable mechanism 47 is driven in the normal direction in this state, the air inside the reduced pressure chamber 60 is discharged through the reduced pressure flow path 48 and the pressurized flow path 51, and the pressure inside the reduced pressure chamber 60 decreases. At this time, the pressure sensor 49 may detect the pressure inside the reduced pressure flow path 48 and the reduced pressure chamber 60. The control unit 19 may control the drive of the pressure variable mechanism 47 based on the detection result of the pressure sensor 49.

When the second storage section 35 is opened to the atmosphere, the drive mechanism 26 opens the ninth selection valve 73i and stops driving the pressure variable mechanism 47. The second storage chamber 68 is connected to the atmosphere via the pressurized flow path 51 and the narrow tube section 72, and is at atmospheric pressure.

When pressurizing the second storage section 35, the drive mechanism 26 opens the first selection valve 73a, the fifth selection valve 73e, and the eighth selection valve 73h, and closes the other selection valves. When the pressure variable mechanism 47 is driven in the forward direction in this state, air flows into the second storage chamber 68 through the pressurized flow path 51, and the pressure in the second storage chamber 68 increases. At this time, the pressure sensor 49 may detect the pressure in the pressurized flow path 51 and the second storage chamber 68. The control unit 19 may control the drive of the pressure variable mechanism 47 based on the detection result of the pressure sensor 49.

Next, the control method of the liquid ejection device 11 will be described with reference to the flowcharts shown in Figures 3 to 9. Here, the order of the steps of each control method can be arbitrarily changed as long as it does not deviate from the purpose of each control method.

The full filling routine shown in FIG. 3 may be executed when the liquid storage unit 24 is first attached to the attachment unit 28. The full filling routine may be executed when the liquid storage unit 24 is attached to the attachment unit 28 after the liquid ejection head 23 has been replaced. In the initial state, the second valve 38, the third valve 40, and all the selection valves are closed.

In step S101, the control unit 19 reduces the pressure inside the first storage unit 33. In step S102, the control unit 19 determines whether the pressure detected by the pressure sensor 49 has fallen below a predetermined pressure. The predetermined pressure is a negative pressure that causes liquid to flow from the liquid storage unit 24 into the first storage unit 33 and raises the first liquid level 66. If the detected pressure detected by the pressure sensor 49 is equal to or greater than the predetermined pressure, step S102 becomes NO and the control unit 19 waits until the detected pressure falls below the predetermined pressure. If the detected pressure falls below the predetermined pressure, step S102 becomes YES and the control unit 19 transitions to step S103.

In step S103, the control unit 19 opens the first storage unit 33 to the atmosphere. In step S104, the control unit 19 opens the second storage unit 35 to the atmosphere. In step S105, the control unit 19 determines whether or not the supply time has elapsed since the first storage unit 33 and the second storage unit 35 were opened to the atmosphere. The supply time is the time required for liquid to be supplied from the first storage unit 33 to the second storage unit 35 and for the heights of the first liquid level 66 and the second liquid level 70 to be the same. If the supply time has not elapsed, step S105 becomes NO, and the control unit 19 waits until the supply time has elapsed. If the supply time has elapsed, step S105 becomes YES, and the control unit 19 transitions the process to step S106. Here, steps S103 and S104 may be performed simultaneously, or step S103 may be performed after step S104.

In step S106, the control unit 19 opens the second valve 38. In step S107, the control unit 19 opens the third valve 40. In step S108, the control unit 19 pressurizes the second storage unit 35. Here, steps S106 and S107 may each be performed simultaneously with step S108 or after step S108.

In step S109, the control unit 19 determines whether the first filling time has elapsed since pressurizing the second storage unit 35. The first filling time is the time required to fill the liquid in the second storage unit 35 into the supply flow path 37 and the recovery flow path 39. If the first filling time has not elapsed, step S109 becomes NO, and the control unit 19 waits until the first filling time has elapsed. If the first filling time has elapsed, step S109 becomes YES, and the control unit 19 transitions to step S110.

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 opens the second storage unit 35 to the atmosphere. In step S113, the control unit 19 reduces the pressure inside the first storage unit 33. In step S114, the control unit 19 determines whether the pressure detected by the pressure sensor 49 has fallen below a predetermined pressure. If the detected pressure detected by the pressure sensor 49 is equal to or greater than the predetermined pressure, step S114 becomes NO, and the control unit 19 waits until the detected pressure falls below the predetermined pressure. If the detected pressure falls below the predetermined pressure, step S114 becomes YES, and the control unit 19 transitions the process to step S115. Here, steps S110 and S111 may each be performed simultaneously with step S112 or after step S112.

In step S115, the control unit 19 opens the first storage unit 33 to the atmosphere. In step S116, the control unit 19 determines whether the supply time has elapsed since the first storage unit 33 was opened to the atmosphere. If the supply time has not elapsed, step S116 becomes NO, and the control unit 19 waits until the supply time has elapsed. If the supply time has elapsed, step S116 becomes YES, and the control unit 19 transitions to step S117.

In step S117, the control unit 19 closes the second valve 38. In step S118, the control unit 19 pressurizes the second storage unit 35. In step S119, the control unit 19 determines whether or not the second filling time has elapsed since the second storage unit 35 was pressurized. The second filling time is the time required to fill the liquid from the supply flow path 37 to the nozzle 22. If the second filling time has not elapsed, step S119 becomes NO, and the control unit 19 waits until the second filling time has elapsed. When the second filling time has elapsed, step S119 becomes YES, and the control unit 19 transitions to the process at step S120. Here, step S117 may be performed simultaneously with step S118 or after step S118.

In step S120, the control unit 19 stops driving the pressure variable mechanism 47. In step S121, the control unit 19 opens the second storage unit 35 to the atmosphere and ends the full filling routine. Here, step S120 may be performed simultaneously with step S121 or after step S121.

Next, the operation when performing full filling will be described.
2, the liquid ejection device 11 reduces the pressure inside the first storage portion 33 using the pressure variable mechanism 47, and supplies liquid from the liquid containing portion 24 to the first storage portion 33. At this time, the pressure in the first storage portion 33 becomes lower than the pressure in the second storage portion 35. Therefore, the first valve 36 is closed. In other words, the liquid ejection device 11 reduces the pressure inside the first storage portion 33, thereby closing the communication passage 34 with the first valve 36.

When the pressure inside the first storage section 33 is reduced, liquid is supplied from the liquid storage section 24 to the first storage section 33, and the first liquid level 66 rises. Because the communication passage 34 is closed, no liquid is supplied to the second storage section 35.

When the first liquid level 66 rises to the standard position, the float valve 61 separates the reduced pressure chamber 60 from the first storage chamber 62. The first storage chamber 62 stops being depressurized, and liquid stops flowing into the first storage section 33. The reduced pressure chamber 60, which is closed by the float valve 61, further reduces pressure. When the pressure detected by the pressure sensor 49 falls below a predetermined pressure, the control section 19 stops driving the pressure variable mechanism 47 and opens the first storage section 33 and the second storage section 35 to the atmosphere.

When the first storage section 33 and the second storage section 35 are opened to the atmosphere, the first valve 36 opens and the communication passage 34 is opened. Specifically, the liquid ejection device 11 opens the communication passage 34 by the first valve 36 and releases the reduced pressure in the first storage section 33 by the pressure variable mechanism 47, and supplies liquid from the first storage section 33 to the second storage section 35 by a head difference. The first liquid level 66 descends by the amount of liquid supplied to the second storage section 35. The second liquid level 70 rises by the amount of liquid supplied from the first storage section 33. When the first liquid level 66 and the second liquid level 70 are at the same height, the flow of liquid from the first storage section 33 to the second storage section 35 stops.

The liquid ejection device 11 opens the second valve 38 and opens the supply flow path 37 through the second valve 38. The liquid ejection device 11 opens the third valve 40 and opens the recovery flow path 39 through the third valve 40. The liquid ejection device 11 pressurizes the second storage section 35 through the pressure variable mechanism 47. At this time, the pressure in the second storage section 35 becomes higher than the pressure in the first storage section 33, so the first valve 36 closes. That is, the liquid ejection device 11 pressurizes the second storage section 35 and closes the communication path 34 through the first valve 36. The liquid in the second storage section 35 flows into the first storage section 33 through the supply flow path 37, the liquid ejection head 23, and the recovery flow path 39. In other words, the liquid ejection device 11 fills the supply flow path 37 and the recovery flow path 39 with the liquid in the second storage section 35.

The liquid ejection device 11 then closes the second valve 38, which then closes the supply flow path 37. The liquid ejection device 11 then closes the third valve 40, which then closes the recovery flow path 39. The liquid ejection device 11 then opens the second storage section 35 to the atmosphere.

The liquid ejection device 11 reduces the pressure inside the first storage section 33 using the pressure variable mechanism 47, and supplies liquid from the liquid storage section 24 to the first storage section 33. At this time, the pressure in the first storage section 33 becomes lower than the pressure in the second storage section 35, and the first valve 36 closes. In other words, the liquid ejection device 11 reduces the pressure inside the first storage section 33, thereby closing the communication passage 34 with the first valve 36.

When the pressure inside the first storage section 33 is reduced, liquid is supplied from the liquid storage section 24 to the first storage section 33, and the first liquid level 66 rises. Because the communication passage 34 is closed, no liquid is supplied to the second storage section 35. When the first liquid level 66 rises to the standard position and the pressure detected by the pressure sensor 49 falls below the predetermined pressure, the control section 19 stops driving the pressure variable mechanism 47 and opens the first storage section 33 to the atmosphere.

Since the second storage section 35 is first opened to the atmosphere, when the first storage section 33 is opened to the atmosphere, the first valve 36 opens and opens the communication passage 34. The liquid ejection device 11 opens the communication passage 34 with the first valve 36 and releases the reduced pressure in the first storage section 33 by the pressure variable mechanism 47, and supplies liquid from the first storage section 33 to the second storage section 35 by a head difference. When the first liquid level 66 and the second liquid level 70 are at the same height, the liquid ejection device 11 opens the second valve 38 and opens the supply flow path 37. At this time, the third valve 40 is closed and closes the recovery flow path 39.

With the recovery passage 39 closed by the third valve 40, the liquid ejection device 11 pressurizes the second storage section 35 by the pressure variable mechanism 47. The liquid ejection device 11 makes the pressure in the second storage section 35 higher than the pressure in the first storage section 33, and closes the communication passage 34 again by the first valve 36. Because the recovery passage 39 is closed, the liquid in the second storage section 35 is supplied to the liquid ejection head 23 through the supply passage 37 and discharged from the nozzle 22. The liquid ejection device 11 fills the second storage section 35 up to the nozzle 22 of the liquid ejection head 23.

When the liquid ejection head 23 is filled with liquid, the liquid ejection device 11 may stop driving the pressure variable mechanism 47 and open the second storage section 35 to the atmosphere. This opens the first valve 36 and opens the communication passage 34. The liquid in the first storage section 33 is supplied to the second storage section 35 via the communication passage 34. The liquid ejection device 11 may close the second valve 38.

The liquid circulation routine shown in FIG. 4 may be executed when liquid circulation is instructed to be executed. Liquid circulation is instructed to be executed, for example, after a full fill has been executed and during standby when no printing or the like is being performed. The control unit 19 may execute the liquid circulation routine periodically.

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 opens the first storage unit 33 to the atmosphere. In step S204, the control unit 19 pressurizes the second storage unit 35. Here, steps S201 to S204 may be performed simultaneously, or the order may be reversed.

In step S205, the control unit 19 determines whether the first liquid level 66 is located at the full position. If the first liquid level 66 is not located at the full position, step S205 becomes NO, and the control unit 19 waits until the first liquid level 66 is located at the full position. If the first liquid level 66 is located at the full position, step S205 becomes YES, and the control unit 19 transitions the process to step S206. In step S206, the control unit 19 closes the second valve 38. In step S207, the control unit 19 opens the second storage unit 35 to the atmosphere, and ends the liquid circulation routine. Here, step S206 may be performed simultaneously with step S207, or may be performed after step S207.

Next, the operation when liquid circulation is performed will be described.
2, the control unit 19 opens the second valve 38, which opens the supply passage 37. The control unit 19 opens the third valve 40, which opens the recovery passage 39.

The liquid ejection device 11 pressurizes the second storage section 35 using the pressure variable mechanism 47, causing the liquid to flow from the second storage section 35 to the first storage section 33 via the liquid ejection head 23. At this time, the pressure in the second storage section 35 becomes higher than the pressure in the first storage section 33. Therefore, the first valve 36 closes. In other words, the liquid ejection device 11 pressurizes the second storage section 35, causing the first valve 36 to close the communication passage 34.

The print routine shown in FIG. 5 may be executed when a print instruction is issued.
In step S301, the control unit 19 opens the first storage unit 33 to the atmosphere. In step S302, the control unit 19 opens the second storage unit 35 to the atmosphere. In step S303, the control unit 19 opens the second valve 38.

In step S304, the control unit 19 determines whether the liquid ejection flow rate generated by ejecting liquid from the nozzle 22 during printing is equal to or greater than a threshold value. The control unit 19 may calculate the ejection flow rate from the print data. If the ejection flow rate is equal to or greater than the threshold value, step S304 becomes YES, and the control unit 19 transitions the process to step S305. In step S305, the control unit 19 opens the third valve 40.

If the discharge flow rate is less than the threshold in step S304, step S304 becomes NO, and the control unit 19 transitions the process to step S306. In step S306, the control unit 19 closes the third valve 40. In step S307, the control unit 19 executes printing and ends the print routine.

Here, steps S301 and S302 may be performed simultaneously with or after step S303, simultaneously with or after step S305, or simultaneously with or after step S306.

Next, the operation when the print routine is executed will be described.
2, when the discharge flow rate when the liquid discharge head 23 discharges liquid onto the medium 12 is less than a threshold value, the control unit 19 opens the second valve 38 and closes the third valve 40. That is, the control unit 19 executes printing in a state in which the supply flow path 37 is opened by the second valve 38 and the recovery flow path 39 is closed by the third valve 40. Therefore, liquid is supplied to the liquid discharge head 23 from the second reservoir 35 via the supply flow path 37.

When the discharge flow rate when the liquid discharge head 23 discharges liquid onto the medium 12 is equal to or greater than the threshold value, the control unit 19 opens the second valve 38 and the third valve 40. That is, the control unit 19 executes printing with the supply flow path 37 opened by the second valve 38 and the recovery flow path 39 opened by the third valve 40. Therefore, the liquid discharge head 23 is supplied with liquid from the second storage unit 35 via the supply flow path 37, and also from the first storage unit 33 via the recovery flow path 39.

The pressurization and discharge routine shown in FIG. 6 is executed when an instruction to execute pressurization and discharge is issued, or when a discharge failure occurs in which liquid cannot be normally discharged from the nozzles 22, or the like.
In step S401, the control unit 19 reduces the pressure inside the first reservoir 33. In step S402, the control unit 19 determines whether the pressure detected by the pressure sensor 49 has fallen below a predetermined pressure. If the detected pressure detected by the pressure sensor 49 is equal to or greater than the predetermined pressure, step S402 becomes NO, and the control unit 19 waits until the detected pressure falls below the predetermined pressure. If the detected pressure falls below the predetermined pressure, step S402 becomes YES, and the control unit 19 transitions to step S403.

In step S403, the control unit 19 opens the first storage unit 33 to the atmosphere. In step S404, the control unit 19 opens the second storage unit 35 to the atmosphere. In step S405, the control unit 19 determines whether the supply time has elapsed since the first storage unit 33 and the second storage unit 35 were opened to the atmosphere. If the supply time has not elapsed, step S405 becomes NO, and the control unit 19 waits until the supply time has elapsed. If the supply time has elapsed, step S405 becomes YES, and the control unit 19 transitions to the process at step S406. Here, steps S403 and S404 may be performed simultaneously, or step S403 may be performed after step S404.

In step S406, the control unit 19 opens the second valve 38. In step S407, the control unit 19 closes the third valve 40. In step S408, the control unit 19 pressurizes the second storage unit 35. In step S409, the control unit 19 determines whether or not a pressurization discharge time has elapsed since the second storage unit 35 was pressurized. The pressurization discharge time is the time required for the pressure pressurizing the second storage unit 35 to be transmitted to the nozzle 22 via the supply flow path 37, and for the liquid to be discharged from the nozzle 22 to restore the state of the nozzle 22. Here, steps S406 and S407 may each be performed simultaneously with step S408 or after step S408.

Until the pressurization and discharge time has elapsed, step S409 remains NO, and the control unit 19 waits until the pressurization and discharge time has elapsed. When the pressurization and discharge time has elapsed, step S409 remains YES, and the control unit 19 transitions the process to step S410. In step S410, the control unit 19 closes the second valve 38. In step S411, the control unit 19 opens the second storage unit 35 to the atmosphere, and ends the pressurization and discharge routine. Here, step S410 may be performed simultaneously with step S411, or may be performed after step S411.

Next, the operation when pressure discharge is performed will be described.
2, the liquid ejection device 11 reduces the pressure inside the first storage portion 33 by the pressure variable mechanism 47. The liquid ejection device 11 closes the first valve 36 by making the pressure inside the first storage portion 33 lower than the pressure inside the second storage portion 35, and the first valve 36 closes the communication passage 34. The liquid ejection device 11 reduces the pressure inside the first storage portion 33 and supplies liquid from the liquid containing portion 24 to the first storage portion 33. Because the communication passage 34 is closed, liquid is supplied to the first storage portion 33 and the first liquid level 66 rises, whereas no liquid is supplied to the second storage portion 35.

When the first liquid level 66 rises to the standard position and the float valve 61 separates the reduced pressure chamber 60 and the first storage chamber 62, the detected pressure detected by the pressure sensor 49 falls below the predetermined pressure. If the pressure detected by the pressure sensor 49 falls below the predetermined pressure while the first storage section 33 is being reduced in pressure by the pressure variable mechanism 47, the liquid ejection device 11 may release the reduced pressure in the first storage section 33 by the pressure variable mechanism 47. The liquid ejection device 11 stops driving the pressure variable mechanism 47 and opens the first storage section 33 and the second storage section 35 to the atmosphere.

When the first storage section 33 and the second storage section 35 are open to the atmosphere, the first valve 36 opens and opens the communication passage 34. Therefore, the liquid ejection device 11 opens the communication passage 34 by the first valve 36 and releases the reduced pressure in the first storage section 33 by the pressure variable mechanism 47, and supplies liquid from the first storage section 33 to the second storage section 35 by a head difference. When the first liquid level 66 and the second liquid level 70 are at the same height, the liquid ejection device 11 opens the second valve 38 and opens the supply flow path 37. At this time, the third valve 40 is closed and closes the recovery flow path 39.

The liquid ejection device 11 pressurizes the second storage section 35 using the pressure variable mechanism 47 to eject the liquid from the nozzle 22. That is, the liquid ejection device 11 makes the pressure in the second storage section 35 higher than the pressure in the first storage section 33, and closes the communication passage 34 again using the first valve 36. The liquid in the second storage section 35 is supplied to the liquid ejection head 23 through the supply flow path 37, and is ejected from the nozzle 22 because the recovery flow path 39 is closed.

The accumulated pressure discharge routine shown in FIG. 7 may be executed when execution of accumulated pressure discharge is instructed, or when the discharge defect is not improved even after execution of pressurized discharge.
In step S501, the control unit 19 reduces the pressure inside the first reservoir 33. In step S502, the control unit 19 determines whether the pressure detected by the pressure sensor 49 has fallen below a predetermined pressure. If the detected pressure detected by the pressure sensor 49 is equal to or greater than the predetermined pressure, step S502 becomes NO, and the control unit 19 waits until the detected pressure falls below the predetermined pressure. If the detected pressure falls below the predetermined pressure, step S502 becomes YES, and the control unit 19 transitions to step S503.

In step S503, the control unit 19 opens the first storage unit 33 to the atmosphere. In step S504, the control unit 19 opens the second storage unit 35 to the atmosphere. In step S506, the control unit 19 closes the second valve 38. In step S507, the control unit 19 closes the third valve 40. In step S508, the control unit 19 determines whether the execution of the first accumulated pressure discharge has been instructed, or whether the execution of the second accumulated pressure discharge, which accumulates a smaller pressure than the first accumulated pressure discharge, has been instructed. If the first accumulated pressure discharge is to be executed, step S508 becomes YES, and the control unit 19 transitions the process to step S509. In step S509, the control unit 19 sets the accumulated pressure time to the first time.

If the second accumulated pressure discharge is to be performed in step S508, step S508 becomes NO, and the control unit 19 transitions the process to step S510. In step S510, the control unit 19 sets the accumulated pressure time to a second time that is shorter than the first time.

In step S511, the control unit 19 pressurizes the second storage unit 35. In step S512, the control unit 19 determines whether a pressure accumulation time, which is an example of a predetermined time, has elapsed since the start of pressurization in the second storage unit 35. If the pressure accumulation time has not elapsed, step S512 becomes NO, and the control unit 19 waits until the pressure accumulation time has elapsed. If the pressure accumulation time has elapsed, step S512 becomes YES, and the control unit 19 transitions to step S513.

In step S513, the control unit 19 opens the second valve 38. In step S514, the control unit 19 determines whether or not the accumulated pressure discharge time has elapsed since the second valve 38 was opened. The accumulated pressure discharge time is the time required for the pressure accumulated in the second storage unit 35 to be transmitted to the nozzle 22 via the supply flow path 37 and for the liquid to be discharged from the nozzle 22.

Until the accumulated pressure discharge time has elapsed, step S514 becomes NO, and the control unit 19 waits until the accumulated pressure discharge time has elapsed. When the accumulated pressure discharge time has elapsed, step S514 becomes YES, and the control unit 19 transitions the process to step S515. In step S515, the control unit 19 closes the second valve 38. In step S516, the control unit 19 opens the second storage unit 35 to the atmosphere, and ends the accumulated pressure discharge routine.

Here, steps S506 and S507 may be performed simultaneously with the start of pressurization in step S511 or immediately after the start of pressurization in step S511. Also, step S515 may be performed simultaneously with step S516 or after step S516. Also, step S515 does not have to be performed.

Next, the operation when discharging the accumulated pressure will be described.
2, the liquid ejection device 11 reduces the pressure inside the first storage portion 33 by the pressure variable mechanism 47. The liquid ejection device 11 closes the first valve 36 by making the pressure inside the first storage portion 33 lower than the pressure inside the second storage portion 35, and the first valve 36 closes the communication passage 34. The liquid ejection device 11 reduces the pressure inside the first storage portion 33 and supplies liquid from the liquid containing portion 24 to the first storage portion 33. Because the communication passage 34 is closed, liquid is supplied to the first storage portion 33 and the first liquid level 66 rises, whereas no liquid is supplied to the second storage portion 35.

When the first liquid level 66 rises to the standard position and the float valve 61 separates the reduced pressure chamber 60 and the first storage chamber 62, the detected pressure detected by the pressure sensor 49 falls below the predetermined pressure. If the pressure detected by the pressure sensor 49 falls below the predetermined pressure while the first storage section 33 is being reduced in pressure by the pressure variable mechanism 47, the liquid ejection device 11 may release the reduced pressure in the first storage section 33 by the pressure variable mechanism 47. The liquid ejection device 11 stops driving the pressure variable mechanism 47 and opens the first storage section 33 and the second storage section 35 to the atmosphere.

When the first storage section 33 and the second storage section 35 are open to the atmosphere, the first valve 36 opens and opens the communication passage 34. The liquid ejection device 11 opens the communication passage 34 with the first valve 36 and releases the reduced pressure in the first storage section 33 caused by the pressure variable mechanism 47, and supplies liquid from the first storage section 33 to the second storage section 35 by a head difference.

The liquid ejection device 11 closes the second valve 38 and closes the supply flow path 37 with the second valve 38. The liquid ejection device 11 closes the third valve 40 and closes the recovery flow path 39 with the third valve 40. The liquid ejection device 11 pressurizes the second storage section 35 with the pressure variable mechanism 47. The liquid ejection device 11 makes the pressure in the second storage section 35 higher than the pressure in the first storage section 33, thereby closing the first valve 36 and closing the communication passage 34 again with the first valve 36. With the communication passage 34 and the supply flow path 37 closed, the liquid ejection device 11 pressurizes the second storage section 35 for a pressure accumulation time with the pressure variable mechanism 47.

The magnitude of the pressure accumulated in the second storage section 35 is proportional to the time for which the second storage section 35 is pressurized with the communication passage 34 and the supply flow path 37 closed. In the first accumulated pressure discharge, the time for which the second storage section 35 is pressurized by the pressure variable mechanism 47 is a first time. In the second accumulated pressure discharge, the time for which the second storage section 35 is pressurized by the pressure variable mechanism 47 is a second time that is shorter than the first time. The pressure accumulated in the first accumulated pressure discharge is greater than the pressure accumulated in the second accumulated pressure discharge. In other words, in the first accumulated pressure discharge, the second valve 38 opens the supply flow path 37 when the second storage section 35 is pressurized with the first pressure. In the second accumulated pressure discharge, the second valve 38 opens the supply flow path 37 when the second storage section 35 is pressurized with the second pressure that is lower than the first pressure.

When the accumulated pressure discharge time has elapsed since pressurizing the second storage section 35, the liquid ejection device 11 opens the second valve 38, which opens the supply flow path 37 to discharge the liquid from the nozzle 22.

The slight pressure discharge routine shown in FIG. 8 may be executed when execution of slight pressure discharge is instructed.
In step S601, the control unit 19 opens the second valve 38. In step S602, the control unit 19 opens the third valve 40. In step S603, the control unit 19 depressurizes the air chamber 53. In step S604, the control unit 19 determines whether or not 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.

Until the depressurization time has elapsed, step S604 remains NO, and the control unit 19 waits until the depressurization time has elapsed. When the depressurization time has elapsed, step S604 remains YES, and the control unit 19 transitions to step S605. In step S605, the control unit 19 closes the second valve 38. In step S606, the control unit 19 closes the third valve 40. In step S607, the control unit 19 pressurizes the air chamber 53.

In step S608, the control unit 19 determines whether or not the slight pressurization time has elapsed since the air chamber 53 was pressurized. The slight pressurization time is the time required for the pressure pressurizing the air chamber 53 to be transmitted to the nozzle 22 via the liquid chamber 41 and the recovery flow path 39.

Until the slight pressurization time has elapsed, step S608 remains NO, and the control unit 19 waits until the slight pressurization time has elapsed. When the slight pressurization time has elapsed, step S608 remains YES, and the control unit 19 transitions to step S609. In step S609, the control unit 19 opens the air chamber 53 to the atmosphere, and ends the slight pressurization exhaust routine.

Here, steps S601 and S602 may be performed simultaneously with step S603 or after step S603. Also, steps S605 and S606 may be performed during step S603, simultaneously with the end of step S603, or after the end of step S603. Also, steps S605 and S606 may be performed simultaneously with step S607 or after step S607.

Next, the operation when slight pressure discharge is performed will be described.
2, 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 and deforms the flexible member 42 to increase the volume of the liquid chamber 41. Liquid flows into the liquid chamber 41 from the first storage unit 33 via the recovery flow path 39, and liquid also flows into the liquid chamber 41 from the second storage unit 35 via the supply flow path 37 and the recovery flow path 39.

When the volume of the liquid chamber 41 reaches its maximum, the control unit 19 closes the second valve 38, which closes the supply flow path 37. The control unit 19 closes the third valve 40, which closes the recovery flow path 39. In this state, the liquid ejection device 11 pressurizes the flexible member 42 by sending pressurized air to the air chamber 53 using the pressure variable mechanism 47. That is, the liquid ejection device 11 pressurizes the flexible member 42 using the pressurizing mechanism 57 to eject liquid from the nozzle 22. 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 pressurized ejection.

The head replacement routine shown in FIG. 9 may be executed when replacing the liquid ejection head 23 .
In step S701, the control unit 19 determines whether or not the liquid storage unit 24 has been removed from the mounting unit 28. If the liquid storage unit 24 is attached to the mounting unit 28, step S701 becomes NO, and the control unit 19 waits until the liquid storage unit 24 is removed. If the liquid storage unit 24 is removed, step S701 becomes YES, and the control unit 19 transitions to step S702.

In step S702, the control unit 19 opens the second valve 38. In step S703, the control unit 19 closes the third valve 40. In step S704, the control unit 19 pressurizes the second storage unit 35. In step S705, the control unit 19 determines whether the first discharge time has elapsed since the second storage unit 35 was pressurized. The first discharge time is the time required to discharge the liquid stored in the second storage unit 35 through the supply flow path 37 and the liquid ejection head 23.

Until the first discharge time has elapsed, step S705 remains NO, and the control unit 19 waits until the first discharge time has elapsed. When the first discharge time has elapsed, step S705 remains YES, and the control unit 19 transitions the process to step S706. In step S706, the control unit 19 opens the third valve 40.

In step S707, the control unit 19 determines whether the second discharge time has elapsed since the third valve 40 was opened. The second discharge time is the time required to recover the liquid in the recovery passage 39 into the first storage unit 33.

Until the second discharge time has elapsed, step S707 remains NO, and the control unit 19 waits until the second discharge time has elapsed. When the second discharge time has elapsed, step S707 remains YES, and the control unit 19 transitions the process to step S708. In step S708, the control unit 19 closes the second valve 38. In step S709, the control unit 19 closes the third valve 40.

In step S710, the control unit 19 opens the second storage unit 35 to the atmosphere. In step S711, the control unit 19 determines whether the liquid ejection head 23 has been replaced. If the liquid ejection head 23 has not been replaced, step S711 becomes NO, and the control unit 19 waits until the liquid ejection head 23 is replaced. If the liquid ejection head 23 has been replaced, step S711 becomes YES, and the control unit 19 ends the head replacement routine.

Here, steps S702 and S703 may be performed simultaneously with the start of pressurization in step S704 or immediately after the start of pressurization in step S704. Also, steps S708 and S709 may be performed simultaneously with step S710 or after step S710.

Next, the head replacement routine will be described.
2, when replacing the liquid ejection head 23, the worker executes a head replacement routine and removes the liquid storage portion 24 from the mounting portion 28. Next, the control unit 19 opens the second valve 38, which opens the supply flow path 37. The control unit 19 closes the third valve 40, which closes the recovery flow path 39. In this state, the control unit 19 pressurizes the second reservoir 35.

Specifically, the liquid ejection device 11 pressurizes the second storage section 35 using the pressure variable mechanism 47, and ejects the liquid from the second storage section 35 to the liquid ejection head 23 from the nozzle 22. At this time, the pressure in the second storage section 35 becomes higher than the pressure in the first storage section 33, so the first valve 36 closes. In other words, by pressurizing the second storage section 35, the liquid ejection device 11 closes the communication passage 34 using the first valve 36.

When the liquid in the second reservoir 35, the supply flow path 37, and the liquid ejection head 23 is discharged, the control unit 19 opens the third valve 40, which opens the recovery flow path 39. That is, the liquid ejection device 11 pressurizes the second reservoir 35 using the pressure variable mechanism 47, and recovers the liquid in the recovery flow path 39 into the first reservoir 33. The operator replaces the liquid ejection head 23 with the liquid drained from the supply flow path 37, the liquid ejection head 23, and the recovery flow path 39.

The effects of this embodiment will be described.
(1) The second storage section 35 is connected to a communication passage 34 communicating with the first storage section 33 and a supply flow passage 37 communicating with the liquid ejection head 23. The communication passage 34 can be closed by the first valve 36 when the pressure variable mechanism 47 pressurizes the inside of the second storage section 35. Therefore, the pressurized liquid in the second storage section 35 is supplied to the liquid ejection head 23 via the supply flow passage 37. Therefore, by pressurizing the liquid in the liquid ejection head 23, the liquid can be discharged from the nozzle 22, and the risk of the liquid ejection head 23 drawing in the liquid from the nozzle 22 can be reduced.

(2) When the pressure in the first storage section 33 is reduced by the pressure variable mechanism 47, liquid is supplied from the liquid storage section 24. When the liquid level in the first storage section 33 reaches a predetermined height, the float valve 61 closes the pressure reduction flow path 48, stopping the reduction in pressure in the first storage section 33. This reduces the risk of liquid overflowing from the first storage section 33.

(3) When the pressure variable mechanism 47 pressurizes the second storage section 35 while the first valve 36 closes the communication passage 34 and the second valve 38 closes the supply flow path 37, a pressurized force is stored in the second storage section 35. Therefore, by opening the second valve 38 while the pressure in the second storage section 35 is high, the high pressure can be transmitted to the liquid ejection head 23, making it easier to eject, for example, a viscous liquid.

(4) When the pressure variable mechanism 47 pressurizes the second storage section 35 with the third valve 40 closed, the liquid is discharged from the liquid ejection head 23. When the pressure variable mechanism 47 pressurizes the second storage section 35 with the third valve 40 open, the liquid in the liquid ejection head 23 is recovered to the first storage section 33 through the recovery flow path 39. Therefore, maintenance can be selected and performed according to, for example, the state of the air bubbles in the supply flow path 37 and the state of the nozzle 22.

(5) For example, when driving the first valve 36 to close the communication passage 34, a drive source for driving the first valve 36 is required. In this regard, the first valve 36 has a check valve. Specifically, the first valve 36 allows the flow of liquid supplied from the first storage section 33 to the second storage section 35 due to the head difference, but restricts the flow of liquid from the second storage section 35 to the first storage section 33 when the second storage section 35 is pressurized. Therefore, the first valve 36 does not need to be driven, and the drive source can be reduced.

(6) Pressurized discharge supplies liquid from the liquid storage section 24 to the first storage section 33, from the first storage section 33 to the second storage section 35, and from the second storage section 35 to the liquid ejection head 23 in that order, and discharges the liquid from the nozzle 22 provided in the liquid ejection head 23. The liquid in the second storage section 35 is pressurized by the pressure variable mechanism 47 with the communication passage 34 closed, and is supplied to the liquid ejection head 23 via the supply flow path 37. Therefore, the liquid ejection device 11 can discharge the liquid from the nozzle 22 by pressurizing the liquid in the liquid ejection head 23, and can reduce the risk of the liquid ejection head 23 drawing in the liquid from the nozzle 22.

(7) The pressure variable mechanism 47 releases the reduced pressure in the first reservoir 33 when the pressure detected by the pressure sensor 49 falls below a predetermined pressure. Therefore, even if the float valve 61 cannot close the reduced pressure flow path 48, for example, when the float valve 61 becomes misaligned, the risk of liquid overflowing from the first reservoir 33 can be reduced.

(8) In the discharge of accumulated pressure, the first valve 36 closes the communication passage 34, and the second valve 38 closes the supply flow path 37, and the pressure variable mechanism 47 pressurizes the second storage section 35, thereby storing pressurized pressure in the second storage section 35. In the discharge of accumulated pressure, the second valve 38 opens the supply flow path 37 after pressurizing the second storage section 35, thereby transmitting the high accumulated pressure to the liquid ejection head 23, making it easier to discharge, for example, viscous liquid.

(9) Total filling is achieved by combining the opening and closing of the first valve 36, the second valve 38, and the third valve 40 with the driving of the pressure variable mechanism 47, thereby supplying liquid from the liquid storage section 24 to the first storage section 33 and filling the second storage section 35, the supply flow path 37, the liquid ejection head 23, and the recovery flow path 39 with liquid. Therefore, total filling can fill the entire flow path with liquid.

This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.
The liquid ejection device 11 may include a wiping member (not shown) that wipes the nozzle surface 21. The liquid ejection device 11 may cause the wiping member to wipe the nozzle surface 21 after discharging the liquid from the nozzles 22. The liquid ejection device 11 may cause the operator to wipe the nozzle surface 21 before removing the liquid ejection head 23.

The control unit 19 may control the opening and closing of the first valve 36. The control unit 19 may close the communication passage 34 using the first valve 36 before depressurizing the first storage unit 33 and before pressurizing the second storage unit 35.

- The second accumulated pressure discharge may be performed by pressurizing the second storage section 35 for a first time with the first valve 36 and the second valve 38 closed to bring the pressure in the second storage section 35 to a first pressure, then opening the first valve 36 to reduce the pressure in the second storage section 35 to a second pressure, and then opening the second valve 38.

- For slight pressurization and discharge, the liquid in the liquid chamber 41 may be pressurized by the spring 54 pressing the flexible member 42. In this case, the control unit 19 reduces the pressure in 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. In the case of a configuration in which the spring 54 presses the flexible member 42, the spring 54 is included in the pressurization mechanism 57.

The liquid ejection device 11 may perform printing in a state where the recovery passageway 39 is opened by the third valve 40 regardless of the ejection flow rate.
The liquid ejection head 23 may have a plurality of pressure chambers individually communicating with the plurality of nozzles 22, a common liquid chamber to which the plurality of pressure chambers communicate, and a filter chamber in which a filter is housed. The first connection part 44 and the second connection part 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 part 44 and the second connection part 45 are connected to the filter chamber, the liquid ejection device 11 can collect air bubbles captured by the filter together with the liquid in the first storage part 33 by performing liquid circulation. The liquid ejection device 11 may perform liquid circulation when air bubbles are generated in the liquid ejection head 23.

- When the liquid ejection device 11 is in standby mode or is turned off, the second valve 38 and the third valve 40 may be closed, and the supply flow path 37 and the recovery flow path 39 may be closed. By closing the supply flow path 37 and the recovery flow path 39, the risk of liquid leaking from the liquid ejection head 23 can be reduced, for example, even if the liquid ejection device 11 is subjected to vibration or impact.

The amount of liquid that the second storage section 35 can store may be less than the amount of liquid required for pressurized discharge. In this case, the control section 19 may alternately pressurize the second storage section 35 to supply liquid from the second storage section 35 to the liquid ejection head 23, and open the second storage section 35 to the atmosphere to supply liquid from the first storage section 33 to the second storage section 35.

- The amount of liquid stored in the second storage section 35 when the first liquid level 66 and the second liquid level 70 are located at the refill position may be greater than the amount required for printing while liquid is being supplied from the liquid storage section 24 to the first storage section 33. This allows printing to continue while liquid is being supplied from the liquid storage section 24 to the first storage section 33.

The amount of liquid contained in the liquid storage unit 24 may be less than the amount of liquid that the supply mechanism 25 can hold. In this case, the liquid storage unit 24 may be replaced midway through full filling, which fills the supply mechanism 25 with liquid.

- The accumulated pressure discharge may be performed by closing the communication passage 34 with the first valve 36 and closing the supply flow path 37 with the second valve 38, pressurizing the second storage section 35, and then opening the supply flow path 37 with the second valve 38 when the pressure sensor 49 detects that a predetermined pressure has been reached. At this time, the control section 19 may perform a first accumulated pressure discharge in which the supply flow path 37 is opened when the pressure sensor 49 detects that a first pressure has been reached, and a second accumulated pressure discharge in which the supply flow path 37 is opened when the pressure sensor 49 detects that a second pressure lower than the first pressure has been reached. The first pressure and the second pressure are greater than the pressure applied to the second storage section 35 during pressurization and discharge.

The control unit 19 may reduce the pressure inside the first storage unit 33 when causing the liquid to flow from the recovery passageway 39 into the first storage unit 33 .
The control unit 19 may remove air bubbles from the liquid by reducing the pressure inside the first storage unit 33 and expanding the air bubbles contained in the liquid stored in the first storage unit 33.

- The liquid ejection device 11 may simultaneously reduce the pressure in the first storage section 33 and increase the pressure in the second storage section 35. Specifically, the liquid ejection device 11 may open the fourth selection valve 73d and the eighth selection valve 73h, close the other selection valves, and drive the pressure variable mechanism 47 in the forward direction. At this time, the liquid ejection device 11 may open the second selection valve 73b and cause the pressure sensor 49 to detect the pressure in the reduced pressure flow path 48. The liquid ejection device 11 may open the fifth selection valve 73e and cause the pressure sensor 49 to detect the pressure in the pressurized flow path 51.

- The flow path resistance when liquid moves in the reduced pressure chamber 60 and the reduced pressure flow path 48 may be greater than the flow path resistance when the first liquid level 66 rises in the first storage chamber 62. The specified pressure that serves as a guide for releasing the reduced pressure in the first storage section 33 when the pressure in the first storage section 33 is being reduced may be a negative pressure that is greater than the negative pressure that raises the first liquid level 66 in the first storage chamber 62 and less than the negative pressure that moves the liquid in the reduced pressure chamber 60 or the reduced pressure flow path 48.

When the liquid volume sensor 63 detects that the first liquid level 66 is at the standard position, the liquid ejection device 11 may release the reduced pressure in the first storage section 33 .
The liquid ejection device 11 may release the reduced pressure in the first reservoir 33 by opening the first selection valve 73a to connect the reduced pressure passage 48 to the atmosphere. In this case, the pressure variable mechanism 47 may continue to be driven.

- Full filling, pressurized discharge, slightly pressurized discharge, and liquid circulation may be performed multiple times or in combination. If the amount of liquid that can be stored in the first storage section 33 is less than the amount of liquid filled in the supply flow path 37, the recovery flow path 39, and the liquid ejection head 23, full filling may be performed multiple times to fill the supply flow path 37, the recovery flow path 39, and the liquid ejection head 23 with liquid. For example, slight pressurized discharge may be performed after full filling. By combining full filling and slight pressurized discharge, the occurrence of ejection defects can be reduced compared to when only full filling is performed.

The first storage section 33 and the second storage section 35 may be integrally configured.
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 passage 37. The pressurizing mechanism 57 may pressurize the liquid chamber provided in the supply flow passage 37.

The pressure varying mechanism 47 may be a diaphragm pump, a piston pump, a gear pump, or the like.
The liquid ejection head 23 may be in a horizontal position with the nozzle surface 21 horizontal, and may eject liquid 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.

The liquid ejection device 11 may include an atmosphere release path that opens the second storage portion 35 to the atmosphere, separate from the pressurized flow path 51 .
9, the control unit 19 may execute steps S702 to S705 again after executing step S710. This allows the liquid collected in the first reservoir 33 to be discharged from the liquid ejection head 23.

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

The technical ideas and effects obtained from the above-described embodiment and modified examples will be described below.
(A) A liquid ejection device includes a liquid ejection head which ejects liquid from a nozzle provided on a nozzle surface, a first storage section which communicates with a liquid storage section which stores the liquid and in which the liquid level fluctuates within a range lower than the nozzle surface, a second storage section which communicates with the first storage section via a communication passage and in which the liquid is supplied from the first storage section by a head difference, a supply flow path which supplies the liquid from the second storage section to the liquid ejection head, a pressure variable mechanism which reduces pressure in the first storage section and pressurizes the second storage section, and a first valve which can close the communication passage when the second storage section is pressurized by the pressure variable mechanism.

According to this configuration, the second storage section is connected to a communication passage that communicates with the first storage section and a supply flow passage that communicates with the liquid ejection head. The communication passage can be closed by the first valve when the pressure variable mechanism pressurizes the second storage section. Therefore, the pressurized liquid in the second storage section is supplied to the liquid ejection head via the supply flow passage. Therefore, by pressurizing the liquid in the liquid ejection head, the liquid can be discharged from the nozzle, reducing the risk of the liquid ejection head drawing in liquid from the nozzle.

(B) In the liquid ejection device, the first storage section may have a float valve that moves in response to the movement of the liquid level in the first storage section, and the float valve may close a pressure reduction flow path that connects the inside of the first storage section to the pressure variable mechanism when the height of the liquid level reaches a predetermined height.

According to this configuration, when the pressure in the first storage section is reduced by the pressure variable mechanism, liquid is supplied from the liquid storage section. When the liquid level in the first storage section reaches a predetermined height, the float valve closes the pressure reduction flow path, stopping the reduction in pressure in the first storage section. This reduces the risk of liquid overflowing from the first storage section.

(C) The liquid ejection device may further include a second valve provided in the supply flow path between the second storage section and the liquid ejection head, the second valve being capable of opening and closing the supply flow path when the second storage section is pressurized by the pressure variable mechanism.

With this configuration, when the pressure variable mechanism pressurizes the second storage section while the first valve closes the communication passage and the second valve closes the supply flow path, a pressurized force is stored in the second storage section. Therefore, by opening the second valve when the pressure in the second storage section is high, high pressure can be transmitted to the liquid ejection head, making it easier to eject, for example, viscous liquid.

(D) The liquid ejection device may further include a recovery passageway that recovers the liquid from the liquid ejection head to the first storage section, and a third valve that is capable of opening and closing the recovery passageway.
According to this configuration, when the pressure variable mechanism pressurizes the second reservoir with the third valve closed, the liquid is discharged from the liquid ejection head. When the pressure variable mechanism pressurizes the second reservoir with the third valve open, the liquid in the liquid ejection head is recovered to the first reservoir through the recovery flow path. Therefore, maintenance can be selected according to, for example, the state of air bubbles in the supply flow path and the state of the nozzle.

(E) In the liquid ejection device, the first valve may have a check valve that allows the liquid to flow from the first storage section to the second storage section and limits the liquid to flow from the second storage section to the first storage section.

For example, when driving the first valve to close the communication passage, a drive source for driving the first valve is required. In this regard, with this configuration, the first valve has a check valve. Specifically, the first valve allows the flow of liquid supplied from the first storage section to the second storage section due to the head difference, but restricts the flow of liquid from the second storage section to the first storage section when the second storage section is pressurized. Therefore, the first valve does not need to be driven, and the drive source can be reduced.

(F) A method for controlling a liquid ejection device, the method comprising: a liquid ejection head that ejects liquid from a nozzle provided on a nozzle face; a first storage section that communicates with a liquid storage section that stores the liquid; a second storage section that communicates with the first storage section via a communication passage; a supply flow path that supplies the liquid from the second storage section to the liquid ejection head; a first valve that can open and close the communication passage; and a pressure variable mechanism that reduces pressure in the first storage section and increases pressure in the second storage section, the method comprising the steps of: closing the communication passage with the first valve; The pressurization and discharge includes: reducing the pressure in the first storage section with the pressure variable mechanism and supplying the liquid from the liquid storage section to the first storage section; opening the communication passage with the first valve and releasing the reduced pressure in the first storage section with the pressure variable mechanism to supply the liquid from the first storage section to the second storage section with a head difference; closing the communication passage again with the first valve; and pressurizing the second storage section with the pressure variable mechanism to discharge the liquid from the nozzle.

According to this method, pressurized discharge sequentially supplies liquid from the liquid storage section to the first storage section, from the first storage section to the second storage section, and from the second storage section to the liquid ejection head, and discharges the liquid from a nozzle provided in the liquid ejection head. The liquid in the second storage section is pressurized by the pressure variable mechanism with the communication passage closed, and is supplied to the liquid ejection head via the supply flow path. Therefore, the liquid ejection device can discharge liquid from the nozzle by pressurizing the liquid in the liquid ejection head, reducing the risk of the liquid ejection head drawing liquid from the nozzle.

(G) In a method for controlling a liquid ejection device, the liquid ejection device further includes a pressure reduction flow path that connects the first storage section with the pressure variable mechanism, a float valve that moves in response to the movement of the liquid level in the first storage section to open and close the pressure reduction flow path, and a pressure sensor that can detect the pressure in the pressure reduction flow path, and when the pressure detected by the pressure sensor falls below a predetermined pressure while the first storage section is being reduced in pressure by the pressure variable mechanism, the pressure reduction in the first storage section by the pressure variable mechanism may be released.

According to this method, the pressure variable mechanism releases the reduced pressure in the first reservoir when the pressure detected by the pressure sensor falls below a predetermined pressure. Therefore, even if the float valve cannot close the reduced pressure flow path, for example, when the float valve becomes displaced, the risk of liquid overflowing from the first reservoir can be reduced.

(H) The method of controlling the liquid ejection device may further include a second valve provided in the supply flow path between the second storage section and the liquid ejection head and capable of opening and closing the supply flow path, and may include closing the communication path with the first valve, reducing the pressure inside the first storage section with the pressure variable mechanism and supplying the liquid from the liquid storage section to the first storage section, opening the communication path with the first valve and releasing the reduced pressure inside the first storage section with the pressure variable mechanism to supply the liquid from the first storage section to the second storage section with a head difference, closing the communication path again with the first valve, closing the supply flow path with the second valve, and pressurizing the second storage section for a predetermined time with the pressure variable mechanism, and then opening the supply flow path with the second valve to discharge the liquid from the nozzle.

According to this method, the accumulated pressure is discharged by pressurizing the second storage section with the pressure variable mechanism while the first valve closes the communication passage and the second valve closes the supply flow path, thereby storing pressure in the second storage section. After pressurizing the second storage section, the second valve opens the supply flow path, so that the accumulated high pressure can be transmitted to the liquid ejection head, making it easier to discharge, for example, thickened liquid.

(I) In a method for controlling a liquid ejection device, the liquid ejection device further comprises a second valve provided in the supply flow path between the second storage section and the liquid ejection head and capable of opening and closing the supply flow path, a recovery flow path that recovers the liquid from the liquid ejection head to the first storage section, and a third valve that can open and close the recovery flow path, and the liquid is supplied from the liquid storage section to the first storage section by closing the communication path with the first valve and reducing the pressure inside the first storage section with the pressure variable mechanism, opening the communication path with the first valve and releasing the reduced pressure inside the first storage section with the pressure variable mechanism, and supplying the liquid from the first storage section to the second storage section with a head difference, closing the communication path again with the first valve and opening the supply flow path with the second valve, The total filling may include pressurizing the second storage section with the pressure variable mechanism to fill the supply flow path and the recovery flow path with the liquid in the second storage section, closing the communication passage with the first valve and depressurizing the first storage section with the pressure variable mechanism to supply the liquid from the liquid storage section to the first storage section, opening the communication passage with the first valve and releasing the depressurization in the first storage section by the pressure variable mechanism to supply the liquid from the first storage section to the second storage section at a head difference, closing the communication passage again with the first valve and closing the recovery flow path with the third valve, pressurizing the second storage section with the pressure variable mechanism, and filling the liquid in the second storage section up to the nozzle of the liquid ejection head.

According to this method, full filling can be achieved by combining the opening and closing of the first valve, the second valve, and the third valve with the driving of the pressure variable mechanism, thereby supplying liquid from the liquid storage section to the first storage section, and filling the second storage section, the supply flow path, the liquid ejection head, and the recovery flow path with liquid. Therefore, full filling can fill the entire flow path with liquid.

11...Liquid ejection device, 12...Medium, 13...Medium storage section, 14...Stacker, 15...Operation section, 16...Image reading section, 17...Automatic feed section, 19...Control section, 21...Nozzle surface, 22...Nozzle, 23...Liquid ejection head, 24...Liquid storage section, 25...Supply mechanism, 26...Drive mechanism, 28...Mounting section, 29...Inlet flow path, 30...Inlet valve, 33...First storage section, 34...Communication passage, 35...Second storage section, 36...First valve, 37...Supply flow path, 38...Second valve, 39...Recovery flow path, 40...Third valve, 41...Liquid chamber, 42...Flexible member, 44...First connection section, 45...Second connection section, 47...Pressure variable mechanism, 48...Reducing Pressure flow path, 49...pressure sensor, 50...atmospheric release path, 51...pressurized flow path, 53...air chamber, 54...spring, 55...air flow path, 57...pressurizing mechanism, 58...micro-pressurizing section, 60...pressurized chamber, 61...float valve, 62...first storage chamber, 63...liquid level sensor, 64...first gas-liquid separation membrane, 65...sealing member, 66...first liquid level, 68...second storage chamber, 69...second gas-liquid separation membrane, 70...second liquid level, 72...thin tube section, 73a...first selection valve, 73b...second selection valve, 73c...third selection valve, 73d...fourth selection valve, 73e...fifth selection valve, 73f...sixth selection valve, 73g...seventh selection valve, 73h...eighth selection valve, 73i...ninth selection valve.

Claims (11)

a liquid ejection head that ejects liquid from nozzles provided on a nozzle surface;
a first reservoir communicating with a liquid storage portion that stores the liquid, the first reservoir having a liquid level fluctuating within a range lower than the nozzle surface;
a second storage portion that communicates with the first storage portion via a communication passage and to which the liquid is supplied from the first storage portion due to a head difference;
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 pressure varying mechanism that reduces pressure in the first storage portion and increases pressure in the second storage portion;
a first valve capable of closing the communication passage when the second storage portion is pressurized by the pressure variable mechanism;
a third valve capable of closing the recovery passage when the second reservoir is pressurized by the pressure variable mechanism;
A liquid ejection device comprising: a liquid ejection head that ejects liquid from nozzles provided on a nozzle surface;
a first reservoir communicating with a liquid storage portion that stores the liquid, the first reservoir having a liquid level fluctuating within a range lower than the nozzle surface;
a second storage portion that communicates with the first storage portion via a communication passage and to which the liquid is supplied from the first storage portion due to a head difference;
a supply flow path that supplies the liquid from the second reservoir to the liquid ejection head;
A pressure varying mechanism that reduces pressure in the first storage portion and increases pressure in the second storage portion;
a first valve capable of closing the communication passage when the second storage portion is pressurized by the pressure variable mechanism;
Equipped with
The first storage portion has a float valve that moves in accordance with the movement of the liquid level in the first storage portion,
The liquid ejection device, wherein the float valve closes a pressure reduction flow passage that connects the inside of the first reservoir with the pressure variable mechanism when the height of the liquid surface reaches a predetermined height . The first storage portion has a float valve that moves in accordance with the movement of the liquid level in the first storage portion,
The liquid ejection device according to claim 1 , wherein the float valve closes a pressure reduction flow path connecting the first storage portion with the pressure variable mechanism when the liquid level reaches a predetermined height. The liquid ejection device according to any one of claims 1 to 3, further comprising a second valve provided in the supply flow path between the second storage section and the liquid ejection head , the second valve being capable of opening and closing the supply flow path when the second storage section is pressurized by the pressure variable mechanism. a recovery flow path that recovers the liquid from the liquid ejection head to the first reservoir;
A third valve capable of opening and closing the recovery passage;
The liquid ejection device according to claim 2 or 4 , further comprising: A liquid ejection device according to any one of claims 1 to 5, characterized in that the first valve has a check valve that allows the flow of the liquid from the first storage section to the second storage section and limits the flow of the liquid from the second storage section to the first storage section. a first reservoir communicating with a liquid storage section that stores the liquid; a second reservoir communicating with the first reservoir via a communication passage; a supply flow path that supplies the liquid from the second reservoir to the liquid discharge head; a recovery flow path that recovers the liquid from the liquid discharge head to the first reservoir; a first valve that can open and close the communication passage; a third valve that can open and close the recovery flow path; and a pressure variable mechanism that reduces pressure in the first reservoir and increases pressure in the second reservoir,
closing the communication passage with the first valve;
reducing pressure in the first reservoir by the pressure variable mechanism and supplying the liquid from the liquid storage portion to the first reservoir;
opening the communication passage by the first valve and releasing the reduced pressure in the first storage portion by the pressure varying mechanism, thereby supplying the liquid from the first storage portion to the second storage portion by a head difference;
closing the communication passage again by the first valve;
closing the recovery passageway with the third valve;
pressurizing the second reservoir with the pressure variable mechanism to discharge the liquid from the nozzle;
A method for controlling a liquid ejection device, comprising the steps of: a pressure adjusting mechanism that reduces pressure in the first storage portion and increases pressure in the second storage portion; a pressure reducing flow path that connects the first storage portion to the pressure adjusting mechanism; a float valve that moves in response to movement of a liquid level in the first storage portion to open and close the pressure reducing flow path; and a pressure sensor that detects pressure in the pressure reducing flow path,
closing the communication passage with the first valve;
reducing pressure in the first reservoir by the pressure variable mechanism and supplying the liquid from the liquid storage portion to the first reservoir;
When the pressure detected by the pressure sensor falls below a predetermined pressure while the pressure in the first reservoir is being reduced by the pressure variable mechanism, the reduction in pressure in the first reservoir by the pressure variable mechanism is released.
opening the communication passage by the first valve and releasing the reduced pressure in the first storage portion by the pressure varying mechanism, thereby supplying the liquid from the first storage portion to the second storage portion by a head difference;
closing the communication passage again by the first valve;
pressurizing the second reservoir with the pressure variable mechanism to discharge the liquid from the nozzle;
A method for controlling a liquid ejection device, comprising the steps of: the liquid ejection device further includes a pressure reduction flow path that connects the inside of the first reservoir with the pressure variable mechanism, a float valve that moves in response to movement of a liquid level in the first reservoir to open and close the pressure reduction flow path, and a pressure sensor that detects pressure in the pressure reduction flow path;
A method for controlling a liquid ejection device as described in claim 7, characterized in that when the pressure detected by the pressure sensor falls below a predetermined pressure while the pressure in the first storage section is being reduced by the pressure variable mechanism, the reduction in pressure in the first storage section by the pressure variable mechanism is released. the liquid ejection device further includes a second valve provided in the supply flow path between the second storage section and the liquid ejection head and capable of opening and closing the supply flow path;
closing the communication passage with the first valve;
reducing pressure in the first reservoir by the pressure variable mechanism and supplying the liquid from the liquid storage portion to the first reservoir;
opening the communication passage by the first valve and releasing the reduced pressure in the first storage portion by the pressure varying mechanism, thereby supplying the liquid from the first storage portion to the second storage portion by a head difference;
closing the communication passage again by the first valve;
closing the supply flow path with the second valve;
pressurizing the second reservoir for a predetermined time by the pressure varying mechanism, and then opening the supply flow path by the second valve to discharge the liquid from the nozzle;
The method for controlling a liquid ejection device according to any one of claims 7 to 9, further comprising the step of: discharging accumulated pressure including the liquid ejection device further includes a second valve provided in the supply flow path between the second storage section and the liquid ejection head and capable of opening and closing the supply flow path, a recovery flow path that recovers the liquid from the liquid ejection head to the first storage section, and a third valve that is capable of opening and closing the recovery flow path,
closing the communication passage with the first valve and reducing pressure in the first reservoir with the pressure variable mechanism to supply the liquid from the liquid storage portion to the first reservoir;
opening the communication passage by the first valve and releasing the reduced pressure in the first storage portion by the pressure varying mechanism, thereby supplying the liquid from the first storage portion to the second storage portion by a head difference;
closing the communication passage again with the first valve and opening the supply flow path with the second valve, and pressurizing the second reservoir with the pressure varying mechanism to fill the liquid in the second reservoir into the supply flow path and the recovery flow path;
closing the communication passage with the first valve and reducing pressure in the first reservoir with the pressure variable mechanism to supply the liquid from the liquid storage portion to the first reservoir;
opening the communication passage by the first valve and releasing the reduced pressure in the first storage portion by the pressure varying mechanism, thereby supplying the liquid from the first storage portion to the second storage portion by a head difference;
The method for controlling a liquid ejection device according to any one of claims 7 to 10, further comprising the steps of: closing the communication passage again with the first valve and closing the recovery flow path with the third valve; pressurizing the second storage section with the pressure variable mechanism; and filling the liquid in the second storage section up to the nozzle of the liquid ejection head.